WO2013008831A1 - Heat processing system and heat processing method - Google Patents

Abstract

The purpose of the present invention is to provide a heat processing system and a heat processing method that are capable of cooling the inner peripheral surface side of a workpiece, in addition to heating the outer peripheral surface side of the workpiece and cooling the outer peripheral surface side of the workpiece, and are also capable of uniformly and continuously cooling the inner peripheral surface side of the workpiece. Said system has: a conveyance device that conveys a hollow cylindrical workpiece (11); an induction heating device (16) that heats the hollow cylindrical workpiece (11) from the outer peripheral surface side; a cooling device (17) that cools the hollow cylindrical workpiece (11) from the outer peripheral surface side; a discharge-side injection device (22N) and an intake-side injection device (21N) that inject a cooling medium towards a cooling range on the inside peripheral surface of the hollow cylindrical workpiece (11), from tip sections; a movement device (22) for the discharge-side injection device that causes the discharge-side injection device (22N) to move; and a movement device (21) for the intake-side injection device that causes the intake-side injection device (21N) to move.

Description

Heat treatment system and heat treatment method

The present invention relates to a technique for continuously cooling the inner peripheral surface side of a plurality of hollow cylindrical workpieces (for example, crawler belt bushes). More specifically, the present invention relates to a technique for continuously cooling the inner peripheral surface side of a plurality of heated workpieces when heat-treating (quenching) the plurality of hollow cylindrical workpieces.

The hollow cylindrical workpiece includes, for example, a bush that is one of the crawler parts of a construction vehicle. However, it is not limited to the bush.
In a hollow cylindrical workpiece such as a crawler belt bush, hardness is required to ensure wear resistance on the inner peripheral surface, the inner peripheral portion that is the vicinity region thereof, the outer peripheral surface, and the outer peripheral portion that is the vicinity region. The At the same time, the thick core portion, which is the portion between the inner peripheral portion and the outer peripheral portion, requires toughness to prevent cracking.
In order to heat-treat a hollow cylindrical workpiece such as a crawler belt bush uniformly and with good productivity, it is desirable to heat-treat the workpiece continuously.

In response to the requirement of continuously heat-treating the hollow cylindrical workpiece, the present applicant is divided into quenching in the first step and quenching in the second step,
In the quenching of the first step, the hollow cylindrical workpiece is continuously fed laterally without any interval, and only from the outer peripheral surface side of the workpiece to Ac ₃ points or more over the entire thickness of the workpiece and Ac ₃ Induction heating to a temperature below the point + 200 ° C,
Using the time until the work reaches the cooling part separated from the heating part, the temperature of the work is made uniform in the longitudinal direction and the thickness direction,
Before the temperature of the workpiece falls to the Ar ₃ point, cooling is started and the workpiece is cooled only from the outer peripheral surface side, and is hardened and cured over the entire thickness of the workpiece,
In the quenching of the second step, the workpiece that has been hardened by hardening over the entire thickness is laterally fed continuously without a gap, and only from the outer peripheral surface side of the workpiece, the outer peripheral surface of the workpiece and the outer peripheral surface. The outer peripheral portion of the work, which is a portion between the outer peripheral surface and a position that is separated from the outer wall by a distance deeper than 1/4 and shallower than 1/2, is guided to a temperature of Ac ₃ points or higher and Ac ₃ points + 200 ° C. or lower. Heated,
After the induction heating is completed and immediately after the induction heating, the workpiece is cooled only from the outer peripheral surface side while continuously feeding the workpiece in a transverse direction without a gap, thereby reducing the workpiece thickness of the workpiece. The effective hardness is set at a position separated from the outer peripheral surface of the workpiece by a distance of / 4 to 1/2, and the hardness on the outer peripheral surface side and the outer peripheral surface is more than the effective hardness at the outer peripheral effective hardness position. In addition, the portion closer to the thick core portion than the outer peripheral effective hardness position is set to a hardness less than the effective hardness, and from the inner peripheral surface of the workpiece by a distance less than ½ of the workpiece thickness. The separated position is made effective hardness, and the inner peripheral portion and the inner peripheral surface of the work, which is the inner peripheral surface side of the inner peripheral portion effective hardness position, are made harder than the effective hardness. Hollow cylindrical shape with a hardness less than the effective hardness in the thick core part side from the effective hardness position We propose a method for heat treating a chromatography click (see Patent Document 1). Here, the thick core portion refers to a portion which exists between the outer peripheral portion and the inner peripheral portion and whose hardness is less than the effective hardness after quenching in the second step described later.

Although the related art (Patent Document 1) is useful, in the quenching in the second step, from the end of induction heating (from only the outer peripheral surface side) to the start of cooling (from only the outer peripheral surface side), the dimensions of the workpiece Depending on the elapsed time, the hardness of the inner peripheral portion may not be ensured, and in the worst case, the inner peripheral surface of the workpiece may be softened.
On the other hand, an inner peripheral surface cooling nozzle is arranged in a hollow area of a hollow cylindrical workpiece, and in addition to heating on the outer peripheral surface side of the work and cooling on the outer peripheral surface side of the work, the work by the inner peripheral surface cooling nozzle is performed. There is also a technique for cooling the inner peripheral surface side of the film (see Patent Document 2).

However, when the inner peripheral surface cooling nozzle is disposed in the hollow region of the work, the work cannot be carried out unless the heat-treated (quenched) work is removed from the inner peripheral surface cooling nozzle. Therefore, in the related art (Patent Document 2), in addition to the step of cooling the inner peripheral surface side of the workpiece by the inner peripheral surface cooling nozzle, the step of removing the inner peripheral surface cooling nozzle from the workpiece that has been subjected to heat treatment (quenching); The step of taking out the workpiece from the heat treatment line, the step of putting a new workpiece into the heat treatment line, and the step of arranging the inner peripheral surface cooling nozzle in the hollow region of the new workpiece are required.
In order to apply the above-described conventional technique (Patent Document 2), these steps (inserting / removing the inner peripheral surface cooling nozzle into and out of the inner peripheral hollow region of the workpiece and inserting / removing the workpiece into / from the heat treatment line) must be performed. Must be a so-called “batch type”. Therefore, in the said prior art (patent document 2), the internal peripheral surface side of a workpiece | work cannot be cooled continuously and uniformly, In the heat processing line which is performing the continuous process, the said prior art (patent document 2). ) Is difficult to apply.

Japanese Patent No. 4187334 Japanese Patent No. 3856545

The present invention has been proposed in view of the problems of the prior art described above, and in addition to heating the outer peripheral surface of the workpiece and cooling the outer peripheral surface of the workpiece, cooling the inner peripheral surface of the workpiece. In addition, an object of the present invention is to provide a heat treatment system and a heat treatment method capable of cooling the inner peripheral surface side of the workpiece uniformly and continuously.

The heat treatment system of the present invention is a heat treatment system (200) for a hollow cylindrical workpiece (11) continuously conveyed,
A transport device (work transport rollers 18 and 19) for transporting the hollow cylindrical workpiece (11);
A heating device (heating coil 16) for heating the hollow cylindrical workpiece (11) from the outer peripheral surface side;
A cooling device (cooling jacket 17) for cooling the hollow cylindrical workpiece (11) from the outer peripheral surface side;
A carry-out side injection device (22N: for example, a carry-out side nozzle) and a carry-in side injection device (21N: for example, a carry-in side nozzle) that injects a cooling medium from the injection port toward the cooling range of the inner peripheral surface of the hollow cylindrical workpiece (11). And
During operation of the heat treatment system (200), at least one of the carry-in side injection device (21N) or the carry-out side injection device (22N) is within the cooling range of the inner peripheral surface of the hollow cylindrical workpiece (11) in the cooling region. It is characterized in that the cooling medium is jetted in the direction.

The heat treatment system of the present invention comprises:
A carry-out side injecting device (22N) that moves between a carry-out side retreat position that does not interfere with the hollow cylindrical workpiece (11) being conveyed and a cooling region;
The carry-in side injection device (21N) includes a carry-in side retreat position that does not interfere with the hollow cylindrical workpiece (11) being transferred, and a moving device of the carry-in side injection device (21N) that moves between the cooling regions,
When carrying out the hollow cylindrical workpiece (11), the carry-in side injection device (21N) is moved to the cooling region, the cooling medium is injected from the carry-in side injection device (21N), and the carry-out side injection device (22N). Are moved to the carry-out side retracted position where they do not interfere with the hollow cylindrical workpiece (11) being conveyed (simultaneous injection of the cooling medium from the carry-in side injection device 21N and movement of the carry-out side injection device 22N to the carry-out side retracted position are performed simultaneously. Including the first function),
When carrying in a new hollow cylindrical workpiece (11), the carry-out side injection device (22N) is moved to the cooling region, the cooling medium is injected from the carry-out side injection device (22N), and the carry-in side injection device (21N). ) To the carry-in side retracted position that does not interfere with the hollow cylindrical workpiece (11) being conveyed (the cooling medium injection from the carry-out side injection device 22N and the movement of the carry-in side injection device 21N to the carry-in side retracted position). It is preferable that the second function is included (including the case where it is performed simultaneously).
In this case, when one of the control related to the first function and the control related to the second function is executed, the third function can be configured so as not to execute the other control.

The heat treatment method of the present invention is a heat treatment method of a hollow cylindrical workpiece (11) conveyed continuously,
Heating the hollow cylindrical workpiece (11) conveyed by the conveying device (18, 19) from the outer peripheral surface side by the heating device (16);
Cooling the hollow cylindrical workpiece (11) conveyed by the conveying device (18, 19) from the outer peripheral surface side by the cooling device (17);
In the cooling region, injecting a cooling medium from the carry-out side injection device (22N) and / or the carry-in side injection device (21N) to the cooling range of the inner peripheral surface of the hollow cylindrical workpiece (11),
In the step of injecting, in the cooling region, at least one of the carry-in side injection device (21) or the carry-out side injection device (22) moves the cooling medium toward the cooling range of the inner peripheral surface of the hollow cylindrical workpiece (11). It is characterized by spraying.

The heat treatment method of the present invention comprises:
By the moving device (22) of the unloading side injection device (22N), the unloading side injection device (22N) is moved between the unloading side retreat position that does not interfere with the hollow cylindrical workpiece (11) being conveyed and the cooling region. Process,
By the moving device (21) of the carry-in side injection device (21N), the carry-in side injection device (21N) is moved between the carry-in side retreat position that does not interfere with the hollow cylindrical workpiece (11) being conveyed and the cooling region. A process,
When cooling the cooling range of the inner peripheral surface of the hollow cylindrical workpiece (11),
When carrying out the hollow cylindrical workpiece (11), the step of injecting the cooling medium from the carry-in side injection device (21N) by placing the carry-in side injection device (21N) in the cooling region, and the carry-out side injection device ( 22N) is positioned at the unloading side retracting position so as not to interfere with the hollow cylindrical workpiece (11) being conveyed,
When carrying in a new hollow cylindrical workpiece (11), the step of injecting the cooling medium from the carry-out side injection device (22N) by placing the carry-out side injection device (22N) in the cooling region, and the carry-in side injection It is preferable to have a step of positioning the device (21N) at the carry-in side retracted position that does not interfere with the hollow cylindrical workpiece (11) being conveyed.
In this case, when either one of the retracting process of the carry-out side injection device (22N) or the retracting process of the carry-in side injection device (21N) is performed, the other process is not performed. be able to.

In the heat treatment method of the present invention, induction heating of quenching in the first step and quenching in the second step is performed,
In the quenching of the first step, the hollow cylindrical workpiece is continuously fed laterally without any interval, and only from the outer peripheral surface side of the workpiece to Ac ₃ points or more over the entire thickness of the workpiece and Ac ₃ Using the time until the workpiece reaches the cooling section separated from the heating section by induction heating to a temperature below the point + 200 ° C, the workpiece temperature is made uniform in the longitudinal direction and the thickness direction, and the workpiece temperature is Ar ₃ points Before cooling down to cool the workpiece from the outer peripheral side, quench hardening over the entire thickness of the workpiece,
In induction heating for quenching in the second step, the outer peripheral surface and the outer peripheral portion of the workpiece are moved at Ac ₃ points or more from only the outer peripheral surface side of the workpiece while laterally feeding the workpiece that has been quenched and hardened over the entire thickness. And it is preferable to heat to a temperature of Ac ₃ points + 200 ° C. or lower.

Moreover, in the heat treatment method of the present invention, induction heating of the first step quenching and the second step quenching is performed,
In the quenching of the first step, the hollow cylindrical workpiece is induction-heated to a temperature of Ac ₃ points or more and Ac ₃ points + 200 ° C. or less over the entire thickness of the workpiece only from the outer peripheral surface side of the workpiece, Immediately after induction heating, cooling is started and the workpiece is cooled only from the outer peripheral surface side, and it is hardened and cured over the entire thickness of the workpiece,
In induction heating for quenching in the second step, the outer peripheral surface and the outer peripheral portion of the workpiece are moved at Ac ₃ points or more from only the outer peripheral surface side of the workpiece while laterally feeding the workpiece that has been quenched and hardened over the entire thickness. And it is preferable to heat to a temperature of Ac ₃ points + 200 ° C. or lower.

In the present invention described above, the cooling range of the inner peripheral surface of the hollow cylindrical workpiece (11) is determined by the effect of heating (induction heating) from the outer peripheral surface side by the heating device (16). A position (P2: see FIG. 6) at which the temperature of the inner peripheral surface of the workpiece (11) starts to rise (when cooling medium is not sprayed on the inner peripheral surface of the workpiece 11) (P2: see FIG. 6), and (cooling) When the medium is not sprayed on the inner peripheral surface of the work 11), the temperature of the inner peripheral surface of the work (11) once exceeded the low-temperature tempering temperature by the cooling on the outer peripheral surface side by the cooling device (17). A range including a region between positions (P3: see FIG. 6) where the temperature is equal to or lower than the tempering temperature is desirable.
Then, the cooling medium from the carry-out side injection device (22N) and / or the carry-in side injection device (21N) is injected into the cooling range.
In carrying out the present invention, the hollow cylindrical workpiece (11) is preferably a crawler belt bush. However, the hollow cylindrical workpiece is not limited to the bush of the crawler belt.

According to the present invention having the above-described configuration, in the system in which the hollow cylindrical workpiece (11) is continuously conveyed and heat-treated, the inner peripheral surface and the inner peripheral portion of the hollow cylindrical workpiece (11) are cooled in the cooling range. , Even if the work (11) is heated from the outer peripheral surface side, before the inner peripheral surface of the work (11) is heated to a temperature exceeding the low-temperature tempering temperature, And before the temperature rises to a temperature at which the inner peripheral part of the work (11) is tempered to a hardness less than the effective hardness, the inner peripheral surface and the inner peripheral part of the work (11) are reliably cooled, The hardness of a peripheral surface and an inner peripheral part can be ensured. Therefore, it can prevent that the internal peripheral surface and internal peripheral part of a workpiece | work (11) soften.

Here, according to the present invention, even when the hollow cylindrical workpiece (11) is carried out and carried in, the workpiece (11) is respectively connected to the carry-out side injection device (22N) and / or the carry-in side injection device (21N). Since the cooling medium can be injected into the cooling range of the inner peripheral surface of the workpiece 11 without interference, the cooling range can be continuously cooled.

According to the present invention, without heating the hollow cylindrical workpiece (11) from the inner peripheral surface side, the outer peripheral surface and the outer peripheral portion and the inner peripheral surface and the inner peripheral portion are made harder than the effective hardness, Heat treatment for making the thick core portion harder than the effective hardness can be continuously performed.
Here, the effective hardness refers to a hardness level that can be regarded as “hardened” when the steel material is hardened to be hardened, and the level of wear resistance required for the hollow cylindrical workpiece (11) and the hollowness. It varies depending on the carbon content of the steel material of the cylindrical workpiece (11).

It is a top view which shows the heat processing line suitable for applying this invention. It is a front view of the apparatus which performs hardening of a 1st process in the apparatus of FIG. It is a front view of the apparatus which performs hardening of a 2nd process in the apparatus of FIG. It is sectional drawing of the cooling part in the hardening of a 2nd process. It is an example of the block diagram which shows embodiment of this invention. It is the A section enlarged view of FIG. In embodiment, it is an example of the flowchart which shows the procedure which cools continuously the internal peripheral surface side of a workpiece | work. In embodiment, it is an example of the flowchart which shows the procedure which carries in a workpiece | work. It is explanatory drawing which shows the state which only the carrying-out side injection device is arrange | positioned in a workpiece | work, cools the internal peripheral surface side of a workpiece | work, and the carrying-in side injection device has evacuated from the workpiece | work. It is explanatory drawing which shows the state which cools the internal peripheral surface side of a workpiece | work with a carrying-out side injection device and a carrying-in side injection device, and exists in the position where the workpiece | work located in the most carrying-out side is detected. It is explanatory drawing which shows the state which only the carrying-in side injection device is arrange | positioned in a workpiece | work, the work inner peripheral surface side was cooled, and the carrying-out side injection device was evacuated from the workpiece | work. It is explanatory drawing which shows the state in which the workpiece | work located in the most carrying out side is carried out. It is explanatory drawing which shows the state which has arrange | positioned the carrying-out side injection device and the carrying-in side injection device in a workpiece | work. It is explanatory drawing which shows the state which only the carrying-out side injection device is arrange | positioned in a workpiece | work, the work inner peripheral surface side was cooled, and the carrying-in side injection device was evacuated from the inside of a workpiece | work. It is explanatory drawing which shows the state in which the workpiece | work was conveyed and the new workpiece | work was carried in.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Prior to the description of the embodiment of the present invention, a heat treatment apparatus for performing a heat treatment suitable for applying the present invention will be described with reference to FIGS.

The heat treatment performed in FIGS. 1 to 4 (heat treatment suitable for applying the present invention) is configured to perform quenching in the first step and quenching in the second step.
In the quenching in the first step, quenching is performed over the entire thickness of the hollow cylindrical workpiece 11 in the region indicated as “Q1” in FIG.
In the quenching in the first step, a hollow cylindrical workpiece (workpiece: for example, a crawler belt bush) 11 is rotated around the workpiece axis and continuously in the horizontal direction without a gap between the workpieces 11. (From right to left as shown by the white arrow in Fig. 1).
By continuously transporting the workpieces 11 without leaving an interval, the jig becomes unnecessary and it is possible to prevent the heat input from being taken away by the jig. Further, it is not necessary to perform temporary heating at the end of the work 11 in the longitudinal direction. Furthermore, by continuously heating, each workpiece 11 can be heated uniformly in the longitudinal direction, and the temperature difference in the longitudinal direction of the workpiece 11 can be reduced.
Here, if the workpiece 11 is continuously conveyed in the vertical direction (vertical direction), the height direction dimension of the heat treatment apparatus becomes too large, which is inconvenient for various operations in the heat treatment, and the ceiling of the building where the apparatus is installed. This will cause interference problems. Therefore, in the heat treatment shown in FIGS. 1 to 4, the workpiece 11 is fed in the horizontal direction (horizontal direction).

In the heating coil (electromagnetic induction heating device) 12, the work 11 is induction-heated from the outer peripheral surface side. Then, induction heating is performed over the entire thickness of the workpiece 11 to a temperature of Ac ₃ points or higher and Ac ₃ points + 200 ° C. (preferably Ac ₃ points + 50 ° C.) or lower.
In induction heating, the heating depth can be accurately set by selecting the frequency of the induction power source. When induction heating is performed by the heating coil 12, the frequency of the induction power source is selected so that the entire thickness of the hollow cylindrical workpiece 11 is heated to the above temperature.

In the quenching in the first step described above, as shown in FIG. 2, the work 11 is transported while being placed on a pair of rotating work transport rollers 14 and 15. The workpiece 11 is conveyed by rotating the workpiece 11 by rotating the workpiece conveying rollers 14 and 15, and slightly tilting one of the pair of workpiece conveying rollers 14 and 15 in the traveling direction of the workpiece 11. Done.
As shown in FIG. 1, the work conveying roller 14 is divided into a plurality of portions 14a, 14b, and 14c in the longitudinal direction, and is connected to rotate integrally with a shaft 14d. Similarly, the work conveying roller 15 is also divided into a plurality of portions 15a, 15b, and 15c in the longitudinal direction, and is connected to rotate integrally with a shaft 15d.

In FIG. 1, the heating coil 12 and the cooling jacket 13 are provided at a certain interval, and the work 11 induction-heated by the heating coil 12 is cooled by the cooling jacket 13 after a predetermined time has passed. . The temperature of the work 11 is substantially uniform in the longitudinal direction and the thickness direction due to heat dissipation and heat conduction of the work 11 after the induction coil is heated by the heating coil 12 until it is cooled by the cooling jacket 13. Become.
After induction heating by the heating coil 12, the temperature of the work 11 gradually decreases due to heat radiation as time elapses. Before the temperature of the workpiece decreases to the Ar ₃ point, the workpiece 11 is cooled only from the outer peripheral surface side by the cooling medium from the cooling jacket 13, and is hardened and cured over the entire thickness of the workpiece 11. Since the entire thickness of the workpiece 11 is rapidly cooled from the Ar ₃ point or more, the entire thickness of the workpiece 11 is hardened by hardening. Thereby, the whole wall thickness of the workpiece | work 11 becomes substantially the same hardness, and a metal structure becomes a martensitic structure.

Although not shown, in the quenching in the first step, the hollow cylindrical workpiece 11 is moved by the heating coil 12 from the outer peripheral surface side of the workpiece 11 to Ac ₃ points or more over the entire thickness of the workpiece 11 and Ac. After induction heating to a temperature of ₃ points + 200 ° C. or lower, the workpiece 11 may be cooled only by the cooling jacket 13 from the outer peripheral surface side.
Here, the heating in the quenching in the first step is not limited to the heating coil 12 as long as a heat treatment for full thickness hardening is performed, and a heating furnace or other heating means can be used.

Next, quenching in the second step will be described. In the quenching in the second step, the outer peripheral surface and the outer peripheral portion of the work 11 are re-quenched.
The quenching in the second step is performed on the workpiece 11 that has been quenched and hardened over the entire thickness after the quenching in the first step, that is, in the region indicated as “Q2” in FIG. Done.
In quenching in the second step, the workpiece 11 is continuously conveyed in the horizontal direction (transversely fed) without any gap between the workpieces while rotating around the workpiece axis. Then, by the heating coil 16, the outer peripheral surface and the outer peripheral portion of the work 11 are induction-heated from the outer peripheral surface side to a temperature of Ac ₃ points or higher and Ac ₃ points + 200 ° C. (preferably Ac ₃ points + 50 ° C.) or lower. .
The upper limit of the induction heating temperature is set to Ac ₃ points + 200 ° C. (preferably Ac ₃ points + 50 ° C.) because the martensite structure grains generated on the outer peripheral surface and the outer peripheral portion of the work 11 by quenching in the second step This prevents the cracking during use from occurring and makes it difficult to progress even if a crack occurs.

Here, the outer peripheral portion that is induction-heated by quenching in the second step is an outer peripheral surface of the hollow cylindrical workpiece 11 and a position separated from the outer peripheral surface by a depth of 1/4 to 1/2 of the thickness of the workpiece. Means the part between.
However, depending on the size (thickness) of the workpiece, the range of the outer peripheral portion is a position separated from the outer peripheral surface of the hollow cylindrical workpiece 11 by a depth of 1/4 to 1/2 of the thickness of the workpiece from the outer peripheral surface. It does not have to be between. For example, it may be between the outer peripheral surface and a position separated from the outer peripheral surface by a depth of 1/5 to 1/3 of the thickness of the workpiece.

As shown in FIG. 3, the rotation of the workpiece 11 and the conveyance in the horizontal direction are performed on a pair of rotating workpiece conveyance rollers 18 and 19 (one roller is slightly inclined with respect to the feeding direction of the workpiece 11). This is done by placing the workpiece 11 on the surface.
The work conveying roller 18 is divided into a plurality of portions 18a and 18b in the longitudinal direction, and is connected so as to rotate integrally with a shaft 18c. The work conveying roller 19 is also divided into a plurality of portions 19a and 19b in the longitudinal direction, and is connected so as to rotate integrally with a shaft 19c.

The workpiece 11 heated from the outer peripheral surface side by the heating coil 16 is immediately after heating (within 3 seconds or less, desirably 2 seconds or less, more desirably 1 second or less from the end of heating), and therefore the temperature of the workpiece 11 is increased. Ac ₃ points or more on the outer peripheral surface and the outer peripheral portion (the portion between the outer peripheral surface of the workpiece and the position separated from the outer peripheral surface of the workpiece by a distance deeper than 1/4 of the workpiece thickness and less than 1/2) 400-700 ° C (high temperature tempering temperature) at the thick core part (the part that exists between the outer peripheral part and the inner peripheral part and the hardness becomes less than the effective hardness after quenching in the second step), the inner peripheral part (The part between the inner peripheral surface of the workpiece and a position separated from the inner peripheral surface of the workpiece by a distance smaller than 1/2 of the workpiece thickness) is less than the high temperature tempering temperature, and low temperature baking is performed on the inner peripheral surface. While the temperature is below the return temperature (the heat input from the outer As shown in FIG. 4, before the inner peripheral surface reaches the high temperature tempering temperature and before the inner peripheral surface exceeds the low temperature tempering temperature), as shown in FIG. By injecting a cooling medium onto the outer peripheral surface, the workpiece 11 is cooled from the outer peripheral surface side. In FIG. 4, the workpiece feeding direction is indicated by a symbol F. Reference Jc indicates a jet of the cooling medium.
By cooling from the outer peripheral surface side, the position separated from the outer peripheral surface of the work by the depth of 1/4 to 1/2 of the wall thickness of the work 11 is made effective hardness, and the outer peripheral portion is more effective than the outer peripheral effective hardness position. The surface side portion and the outer peripheral surface are made harder than the effective hardness, and the portion closer to the thick core portion than the outer peripheral portion effective hardness position is made harder than the effective hardness, and the thickness of the workpiece 11 is increased. The position separated from the inner peripheral surface of the work 11 by a depth less than ½ is made effective hardness, and the part on the inner peripheral surface side and the inner peripheral surface of the work 11 from the inner peripheral effective hardness position are effectively hardened. The thickness of the thick core portion side from the inner peripheral effective hardness position of the work 11 is less than the effective hardness.

However, only with the heat treatment described with reference to FIGS. 1 to 4 (heat treatment suitable for applying the present invention), the dimensions of the workpiece 11 and only the outer peripheral surface side of the workpiece from the end of induction heating in quenching in the second step. Depending on the elapsed time from the start of cooling to the start of cooling, the hardness of the inner peripheral surface and the inner peripheral portion may not be ensured, and in the worst case, the inner peripheral surface of the workpiece 11 is softened.
Therefore, according to the illustrated embodiment of the present invention, in addition to injecting a cooling medium from the cooling jacket 17 and cooling the work 11 from the outer peripheral surface side, the heating coil 16 is induction-heated from the outer peripheral surface side. A cooling medium is directly injected into the cooling range (described later) of the inner peripheral surface of the work 11 to cool it.
Thereby, the hardness of an inner peripheral surface and an inner peripheral part is ensured, and the inner peripheral surface of the workpiece | work 11 is prevented from softening.
In addition, in the illustrated embodiment of the present invention, the inner peripheral surface side of the workpiece 11 that is continuously conveyed and induction-heated by the heating coil 16 is continuously transferred without performing so-called batch processing. Can be cooled to.

Hereinafter, with reference to FIGS. 5 to 16, an embodiment of the present invention in which a cooling medium is continuously injected directly into a cooling range (described later) on the inner peripheral surface of the workpiece 11 that is continuously conveyed will be described.
First, the heat treatment system of the present invention will be described with reference to FIG.
The entire heat treatment system shown in FIG. 5 is denoted by reference numeral 200, and constitutes an area labeled “Q2” in FIG.
In order to clearly express the configuration, the work conveying rollers 18 and 19 (FIG. 3) are omitted in FIG. Further, the workpiece 11 (11-1 to 11-3) is shown in a cross section in the longitudinal direction.
5, 6, and 9 to 15, the left side in the figure is the “carry-out side”, and the right side in the figure is the “carry-in side”. 5, 6, and 9 to 15, the conveyance direction of the workpiece 11 is indicated by an arrow F.

In FIG. 5, the heat treatment system 200 includes a heating coil 16, a cooling jacket 17, a carry-in side air cylinder 21, a carry-out side air cylinder 22, a pressure source (for example, a high-pressure air tank) 23, and a carry-in side flow path switching valve. 24, a carry-out side flow path switching valve 25, and a carry-in device 30. The carry-in side air cylinder 21 and the carry-out side air cylinder 22 may be actuators of other types such as a hydraulic type and an electric type.
For clarity of illustration, in FIGS. 5, 6, and 9 to 15, the pair of rotating workpiece transport rollers 18 and 19 (see FIG. 3) are omitted.
FIG. 5 shows a state where the piston rods 21r and 22r of the air cylinder are extended.

The piston rod 21r of the carry-in side air cylinder 21 constitutes a coolant injection device (hereinafter referred to as “carry-in side injection device”) 21N. Although not explicitly shown in FIG. 5, a line for supplying a cooling medium is provided in the carry-in side injection device 21N, and the line communicates with the cooling medium pumping device 26 via the line Lw6.
On the other hand, the piston rod 22r of the carry-out side air cylinder 22 also constitutes a coolant injection device (hereinafter referred to as “carry-out side injection device”) 22N. A line for supplying a cooling medium is also provided in the carry-out side injection device 22N, and the line communicates with the cooling medium pumping device 27 via a line Lw7.
Although the cooling medium pumping devices 26 and 27 are shown as separate bodies in FIG. 5, they can be configured by the same device.

Although not shown, the sensor LS1 for confirming the unloading of the workpiece 11 and the sensor LS2 for confirming the loading of the workpiece 11 are not used, and the workpiece unloading and loading of the workpiece are performed based on the conveying speed of the workpiece 11, the total length of the workpiece 11, and the like. It is also possible to calculate the expected time and control the operation of various devices according to the calculated time. It is also possible to control the operation of various devices by visual observation of the operator.
In the illustrated embodiment, in order to increase the reliability of automatic control, control using a sensor is illustrated and described, and the technical scope of the present invention is not limited.

Here, although not clearly shown, in the boundary portion between the region indicated as “Q1” and the region indicated as “Q2” in FIG. 1, the workpiece 11 that has been quenched in the first step described above. Is waiting at the carry-in device 30 (see FIG. 5).
In the quenching in the first step, the entire thickness of the workpiece 11 is heated to a temperature of Ac ₃ points or higher and Ac ₃ points + 200 ° C., preferably Ac ₃ points + 50 ° C. or lower. Then, the workpiece 11 is cooled by the cooling medium from the cooling jacket 13 and is hardened and cured over the entire thickness of the workpiece 11. The heating in the quenching in the first step is not limited to induction heating, but may be another heating method such as heating in a heating furnace. Further, the cooling in the quenching in the first step is not limited to cooling from the outer peripheral surface side as long as it can be cured over the entire thickness, but cooling from the inner peripheral surface side may be performed. Cooling from both sides on the peripheral surface side may also be used.
The workpiece 11 waiting in the carry-in device 30 is carried into the heat treatment system 200 of FIG. Details of the delivery will also be described later.

The workpiece 11 (11-1 to 11-3) waiting in the carry-in device 30 is transferred from the right side (load-in side) to the left side (unload-side) in FIG. 5 by transfer rollers 18 and 19 (not shown in FIG. 5). ).
The cooling range (described later with reference to FIG. 6) on the inner peripheral surface of the work 11 that is being induction-heated by the heating coil 16 or induction-heated is the carry-out side injection device 22N and / or the carry-in side injection device. It is cooled by the cooling medium sprayed from 21N.

In the carry-out side injection device 22N and / or the carry-in side injection device 21N, an injection hole for cooling medium injection is formed in the vicinity of the tip on the opposite side. In FIG. 6, the injection hole of the carry-out side injection device 22N is indicated by reference numeral 22n, and the injection hole of the carry-in side injection device 21N is indicated by reference numeral 21n.
In FIG. 6, the arrows coming out of the injection holes 21n and 22n indicate the cooling medium being injected. However, the position and number of the injection holes and the direction of the cooling medium being injected are only examples, and are limited to the illustrated examples as long as the cooling range of the inner peripheral surface and the inner peripheral portion of the work 11 can be reliably cooled. Not.
5 and 6, the injection hole 22n (FIG. 6) of the carry-out side injection device 22N is provided with a cooling medium via a cooling medium supply line (not shown) and a line Lw7 (FIG. 5) of the carry-out side injection device 22N. It communicates with the pressure feeding device 27 (FIG. 5). The injection hole 21n (FIG. 6) of the carry-in side injection device 21N is connected to the cooling medium pumping device 26 (FIG. 5) via the cooling medium supply line (not shown) and the line Lw6 (FIG. 5) of the carry-in side injection device 21N. It communicates with 5).

In FIG. 5, the carry-out side injection device 22 </ b> N extends to the carry-in side (right side in FIG. 5) in parallel with the movement direction of the workpiece 11 (conveyance direction: left-right direction in FIG. 5) as the carry-out side air cylinder 22 extends. Stretch toward. And when the carrying-out side air cylinder 22 contracts, it contracts to the carrying-out side (left side in FIG. 5).
The carry-in side injection device 21 </ b> N extends toward the carry-out side (left side in FIG. 5) in parallel with the moving direction of the workpiece 11 when the carry-in side air cylinder 21 extends. And when the carrying-in side air cylinder 21 contracts, it shrinks to the loading side (right side in FIG. 5).

In the heat treatment system 200 shown in FIG. 5, the “second step hardening” in the heat treatment described with reference to FIGS. 1 to 3 is performed on the workpiece 11. As described above, the conveying direction of the workpiece 11 is indicated by the arrow F in FIGS. 5, 6, and 9 to 15.
That is, by the heating coil 16, the outer peripheral surface and the outer peripheral portion of the work 11 are moved from the outer peripheral surface side of the work 11 to a temperature of Ac ₃ points or higher and Ac ₃ points + 200 ° C. or lower, preferably Ac ₃ points + 50 ° C. or lower. Immediately after that, the work 11 is cooled from the outer peripheral surface side by the cooling jacket 17.
At the same time, in the heat treatment system 200 shown in FIG. 5, the outer peripheral surface and the outer peripheral portion are being induction-heated by the heating coil 16, or the carry-out side injection device 22 </ b> N and / or the inner peripheral surface of the work 11 that has been induction-heated. The cooling medium is directly injected from the carry-in side injection device 21N to cool the cooling range on the inner peripheral surface of the work 11.

The cooling range on the inner peripheral surface side of the work 11 to which the cooling medium is injected from the carry-out side injection device 22N and / or the carry-in side injection device 21N is shown in detail in FIG.
In FIG. 6, symbol P <b> 1 schematically shows a position where the influence of induction heating from the outer peripheral surface side by the heating coil 16 starts on the outer peripheral surface of the workpiece 11. And the code | symbol P2 has the influence of the induction heating from the outer peripheral surface side by the heating coil 16 to the inner peripheral part and inner peripheral surface of the workpiece | work 11 (when the cooling medium is not injected to the inner peripheral surface of the workpiece | work 11). The position where the temperature of the inner peripheral surface of the workpiece 11 starts to rise is shown. Further, the symbol P3 indicates that the temperature of the inner peripheral surface of the work 11 once exceeded the low-temperature tempering temperature (when the cooling medium is not sprayed on the inner peripheral surface of the work 11) from the outer peripheral surface side by the cooling jacket 17. The position where the temperature is lower than the low-temperature tempering temperature by cooling is shown. When the cooling medium is not sprayed on the inner peripheral surface of the work 11 and the inner peripheral surface and the inner peripheral portion of the work 11 are not cooled, the temperature of the inner peripheral surface of the work 11 rises and exceeds the low-temperature tempering temperature. In some cases, the inner periphery of the work 11 reaches the high-temperature tempering temperature.

At least a position P2 at which the temperature of the inner peripheral surface of the work 11 starts to rise unless the inner peripheral surface and the inner peripheral portion of the work 11 are cooled by injecting a cooling medium onto the inner peripheral surface of the work 11, When the inner peripheral surface and the inner peripheral portion of the workpiece 11 are not cooled by injecting the cooling medium onto the inner peripheral surface of the workpiece 11, the temperature of the inner peripheral surface of the workpiece 11 that has once exceeded the low-temperature tempering temperature is cooled. The region between the positions P3 where the temperature is again lower than the low-temperature tempering temperature due to cooling from the outer peripheral surface side by the jacket 17 is the inner peripheral surface and inner peripheral surface of the work 11 without spraying the cooling medium onto the inner peripheral surface of the work 11. If the part is not cooled, it may be softened. On the other hand, if the cooling medium is sprayed in a range (cooling range) including the position between the positions P2 to P3 on the inner peripheral surface, the temperature rise on the inner peripheral surface and the inner peripheral portion can be prevented, and softening can be prevented.
In other words, a range (cooling range) in which the cooling medium is injected and cooled from the carry-out side injection device 22N and / or the carry-in side injection device 21N to the inner peripheral surface of the work 11 is in the longitudinal direction of the work 11. It is necessary to include the region between P2 and P3 described above.
The cooling range is a range from the vicinity of the inlet of the heating coil 16 to the vicinity of the center of the cooling jacket 17 in the traveling direction of the workpiece 11.

Here, the positions P1 to P3 in FIG. 6 are merely examples. The positions P1 to P3 differ from case to case depending on the thickness of the workpiece 11, the conveyance speed of the workpiece 11, the heating capacity of the heating coil 16, _three points Ac, and the like.
In FIG. 6, the position P <b> 1 is shown as a point on the outer peripheral surface of the work 11, and the positions P <b> 2 and P <b> 3 are shown as points on the inner peripheral surface of the work 11. However, the position P1 extends over the entire circumferential direction on the outer peripheral surface of the workpiece 11, and the positions P2 and P3 extend over the entire circumferential direction on the inner peripheral surface of the workpiece 11, respectively.

In FIG. 6, for the sake of simplification, the cooling medium injected from the carry-out side injection device 22 </ b> N is shown as being injected only in the upper region of FIG. 6 on the inner peripheral surface of the work 11. It is shown that the cooling medium injected from the injection device 21N is injected only into the area below the inner peripheral surface of the workpiece 11 in FIG.
However, both the cooling medium injected from the carry-out side injection device 22N and the cooling medium injected from the carry-in side injection device 21N are all in the circumferential direction of the inner peripheral surface of the work 11 with respect to the cooling range on the inner peripheral surface of the work 11. Has been injected.

Although not clearly shown in FIGS. 5 and 9 to 15, the range in which the cooling medium from the carry-out side injection device 22N is injected onto the inner peripheral surface of the work 11 and the carry-in / out side injection device 21N are also shown. The cooling medium is injected into the inner peripheral surface of the work 11 in the same range, and is injected into a region (cooling range) including the interval between P2 and P3 on the inner peripheral surface of the work 11.
In FIG. 6, the cooling medium from the carry-out side injection device 22N is injected radially outward of the work 11, and the cooling medium from the carry-in / out side injection device 21N is in the radial direction of the work 11 (of the work 11). Although it is injected in an inclined direction (in the axial direction or the longitudinal direction), the cooling medium injection direction is not limited to the illustrated direction. There is no particular limitation as long as the cooling medium is injected over the entire inner peripheral surface of the cooling range on the inner peripheral surface of the workpiece 11.

The hollow cylindrical workpiece 11 is induction-heated by the heating coil 16 from the outer peripheral surface side to a temperature of Ac ₃ points or higher and Ac ₃ points + 200 ° C. or lower, preferably Ac ₃ points + 50 ° C. or lower. In the case of not cooling from the inner peripheral surface side during or after induction heating, the inner peripheral surface and inner peripheral portion of the work 11 are softened by being heated to the inner peripheral surface side of the work 11 by heat transfer. There is a possibility.
On the other hand, in the illustrated embodiment of the present invention, as shown in FIG. 6, the cooling medium is injected onto the inner peripheral surface of the work 11 by the carry-out side injection device 22N and / or the carry-in side injection device 21N. (In the case where the influence of induction heating from the outer peripheral surface side by the heating coil 16 starts to reach the inner peripheral portion and the inner peripheral surface of the work 11 and the cooling medium is not sprayed to the inner peripheral surface of the work 11, When the temperature of the surface P2 starts to rise and when the cooling medium is not sprayed on the inner peripheral surface of the workpiece 11, the temperature of the inner peripheral surface of the workpiece 11 is low due to cooling from the outer peripheral surface side by the cooling jacket 17. The range including between the positions P3 where the temperature is equal to or lower than the tempering temperature is cooled. Therefore, it can prevent that the internal peripheral surface and internal peripheral part of the workpiece | work 11 soften.

Next, a procedure for cooling the inner peripheral surface side of the work 11 by the heat treatment system 200 will be described with reference mainly to FIG. 7 and also with reference to FIGS.
In step S <b> 1 of FIG. 7, the control unit 50 determines whether or not the operation start condition of the system 200 is satisfied. Then, the system 200 waits for operation until the operation start condition is satisfied (step S1 is NO loop).
If the operation start condition of the system 200 is satisfied (step S1 is YES), the process proceeds to step S2.

In the illustrated embodiment, the main operation start conditions determined in step S1 are as follows.
(1) The carry-out side injection device 22N is in a state capable of injecting the cooling medium.
(2) The cooling medium can be ejected from the cooling jacket 17.
Here, if both or only one of the conditions (1) and (2) is satisfied, it can be set to determine that the operation start condition of the system 200 is satisfied. Moreover, conditions different from the above (1) and (2) can be set as the operation start conditions.

In step S2 of FIG. 7, the operation of the heat treatment system 200 is started. First, as shown in FIG. 9, the carry-out side injection device 22N extends, and the injection holes 22n can inject the cooling medium into the cooling range. The cooling medium is jetted from the carry-out side injection device 22N to the cooling range of the inner peripheral surface of the workpiece 11 in the cooling zone.
FIG. 9 shows a state in which the cooling medium is injected into the cooling range of the inner peripheral surfaces of the workpieces 11-2 and 11-3. Then, the process proceeds to step S3. The carry-in side end of the carry-out side injection device 22N is a position at which the cooling medium jetted from the injection hole 22n when the carry-out side injection device 22N expands is injected into the cooling range including the positions P2 and P3. I mean.
The carry-in side injection device 21N not shown in FIG. 9 is retracted and retracted to the carry-in side (right side in FIG. 9) end (the carry-in side injection device 21N is a newly loaded workpiece 11-4 (see FIG. 9). 15), and has moved to the carry-in side retreat position that does not interfere with the above.

In step S3 of FIG. 7, the control unit 50 determines whether or not the work 11 (11-1) located closest to the carry-out side has reached the position (the carry-out position) to be carried out by the carry-out confirmation sensor LS1. Judging.
If the carry-out confirmation sensor LS1 does not detect that the work 11-1 located closest to the carry-out side has reached the position to be carried out (NO in step S3), the cooling medium is injected from the carry-out side injection device 22N. Thus, the state of cooling the cooling range on the inner peripheral surface side of the workpiece 11 is maintained.
If the carry-out confirmation sensor LS1 detects that the work 11-1 located closest to the carry-out side has reached the position to be carried out (YES in Step S3), the process proceeds to Step S4, and the carry-in side injection device 21N Give a forward command. In that case, for example, the carry-in side air cylinder 21 is extended. Then, the process proceeds to step S5.

In step S5 of FIG. 7, a position or region (cooling region, unloading side end portion) where the carry-in side injection device 21N extends and the cooling medium can be injected from the injection hole 21n to the cooling range of the inner peripheral surface of the work 11. ) Is determined. The carry-out side end of the carry-in side injection device 21N is a position where the cooling medium injected from the injection hole 21n when the carry-in side injection device 21N is extended is injected into a cooling range including the positions P2 and P3. I mean.
If the carry-in side injection device 21N has reached the carry-out side end (step S5 is YES), the process proceeds to step S6. In step S6, the cooling medium is injected from the carry-in side injection device 21N to the cooling position on the inner peripheral surface of the workpiece 11 (FIG. 10).

As shown in FIG. 10, even when the carry-in side injection device 21N is at the carry-out side end portion and the carry-out side injection device 22N is at the carry-in side end portion, the carry-in side injection device 21N and the carry-out side injection device 22N are It is comprised so that it may not interfere with each other.

Here, in the illustrated embodiment, the carry-in side injection device 21N jets the cooling medium after reaching the carry-out side end (see FIG. 10), but the timing of starting the cooling medium injection is limited to this. It is not a thing.
The “cooling medium injection start position” is not limited to the “carry-out side end” in the carry-in side injection device 21N, and any position that can inject the cooling medium into the cooling range on the inner peripheral surface of the workpiece 11 It can be set on a case-by-case basis in response to various conditions.
The carry-in side injection device 21 </ b> N is in the cooling region except when the work 11 is carried in, and may inject the cooling medium into the cooling range of the work 11.

In step S6 of FIG. 7, after the cooling medium is injected from the carry-in side injection device 21N into the cooling range of the inner peripheral surface of the workpiece 11 (FIG. 10), the process proceeds to step S7, and the control unit 50 moves the carry-out side injection device 22N to A retraction command is given, and the carry-out side air cylinder 22 is contracted. Then, the process proceeds to step S8.
In step S8, the control unit 50 transmits a control signal to the cooling medium pumping device 27 to cut off the supply of the cooling medium, thereby stopping the injection of the cooling medium from the carry-out side injection device 22N. Then, the process proceeds to step S9. Instead of transmitting a control signal to the cooling medium pumping device 27, an electromagnetic valve can be provided on the cooling medium supply line to control the opening and closing of the electromagnetic valve.

In step S9, the carry-out side air cylinder 22 is contracted, and as shown in FIG. 11, the carry-out side injection device 22N is retreated to a position where it does not interfere with the workpiece 11 being carried (a carry-out side retreat position). FIG. 11 shows a state where the carry-out side air cylinder 22 has already been retracted (a state where the carry-out side injection device 22N has been moved to the carry-out side retracted position and is waiting for the work 11 to be unloaded). Then, the process proceeds to step S10.
Even if the ejection of the cooling medium from the carry-out side injection device 22N is not stopped, the carry-out side injection device 22N can be moved to the carry-out side retracted position, and there is no problem in carrying out the workpiece 11. However, in the illustrated embodiment, in consideration of scattering of the cooling medium, the ejection of the cooling medium is stopped, and then the carry-out side injection device 22N is moved to the carry-out side retracted position. And in the state of FIG. 11, injection of the cooling medium from the carrying-out side injection device 22N is stopped.
In FIG. 11, the cooling medium from the carry-in side injection device 21 </ b> N is injected into the cooling range of the inner peripheral surface of the work 11.

In step S10 of FIG. 7, if the unloading confirmation sensor LS1 detects the workpiece 11 (YES in step S10), as shown in FIGS. 9 to 11, the workpiece 11-1 located closest to the unloading side is shown. Has not been carried out yet, the state shown in FIG. 11 is continued (a loop in which step S10 is YES).

On the other hand, if the unloading confirmation sensor LS1 does not detect the workpiece 11 (NO in step S10), as shown in FIG. 12, the workpiece 11 located on the most unloading side or on the leftmost side in FIGS. It is determined that -1 has been carried out. Then, the process proceeds to step S11, a forward command is given to the carry-out side injection device 22N, and the carry-out side air cylinder 22 is extended. Then, the process proceeds to step S12.
In FIG. 12, the workpiece 11-1 is shown in a state where the workpiece 11-1 is dropped, but the workpiece unloading according to the present invention is not limited to dropping. For example, the work 11-1 may be carried out by taking out the work 11-1 with a carry-out device (not shown) (for example, an industrial robot hand).
Also in FIG. 12, the cooling medium from the carry-in side injection device 21N is injected into the cooling range of the inner peripheral surface of the workpiece 11.

In step S12, it is determined whether or not the carry-out side injection device 22N has reached the carry-in side end. If the carry-out side injection device 22N has not reached the carry-in side end (NO in step S12), the process waits until the carry-out side injection device 22N reaches the carry-in side end (NO loop in step S12).
If the carry-out side injection device 22N has reached the carry-in side end (step S12 is YES), the process proceeds to step S13. In step S13, the supply of the cooling medium from the cooling medium pumping device 27 is restarted, and the cooling medium is injected from the carry-out side injection device 22N to cool the cooling range of the inner peripheral surface of the workpiece 11 (FIG. 13). Then, the process proceeds to step S14.
In FIG. 13, although not clearly shown, both the cooling medium injected from the carry-in side injection device 21N and the cooling medium injected from the carry-out side injection device 22N are within the cooling range of the inner peripheral surface of the workpiece 11. Being jetted.

The “cooling medium injection start position” is not limited to the “carry-in side end” in the carry-out side injection device 22N, and the cooling medium is supplied from the carry-out side injection device 22N to the cooling range of the inner peripheral surface of the workpiece 11. Any position or region where injection can be performed can be set on a case-by-case basis corresponding to various conditions.
The carry-out side injection device 22 </ b> N is in the cooling region except when the work 11 is carried out, and the cooling medium may be injected into the cooling range of the work 11.

In step S14, the control unit 50 gives a retract command to the carry-in side injection device 21N and contracts the carry-in side air cylinder 21 (see FIG. 14).
In step S15, the control unit 50 cuts off the supply of the cooling medium from the cooling medium pumping device 26, and stops the injection of the cooling medium in the carry-in side injection device 21N. Even if the injection of the cooling medium from the carry-in side injection device 21N is not stopped, the carry-in side injection device 21N can be moved to the carry-in side retracted position. After stopping the injection, it is preferable to move the carry-in side injection device 21N to the carry-in side retracted position.
If the injection of the cooling medium in the carry-in side injection device 21N is stopped, the process proceeds to step S16, a retraction command is given to the carry-in side injection device 21N, and the carry-in side air cylinder 21 is contracted.
FIG. 14 shows a state where the carry-in air cylinder 21 has already been retracted.

If the carry-in side air cylinder 21 has been withdrawn in step S16 in FIG. If the work of the heat treatment system 200 is to be finished (step S17 is YES), the control is finished as it is. If the operation of the heat treatment system 200 is to be continued, the process returns to step S3, and the processes after step S3 are repeated.

Next, based on the flowchart of FIG. 8, the new workpiece 11-4 is heat-treated with reference also to FIG. 14 showing the state before the new workpiece is carried in and FIG. 15 showing the state where the new workpiece is loaded. A procedure for carrying in the system 200 will be described.
In step S <b> 21 of FIG. 8, the control unit 50 determines whether or not the loading device 30 is ready for operation. If the operation preparation of the carrying-in apparatus 30 is ready (step S21 is YES), it will progress to step S22.
If the operation preparation of the carrying-in apparatus 30 is not ready (step S21 is NO), it will progress to step S25.

In step S22, the control unit 50 determines whether or not the loading confirmation sensor LS2 detects a workpiece, that is, whether or not a new workpiece 11 can be loaded.
If the workpiece 11 (11-3) located on the most carry-in side (the rightmost side in FIG. 14) exists at a position immediately below the carry-in confirmation sensor LS2 (YES in step S22: In the state shown in FIG. 14) No), it is determined that it is difficult to carry the new workpiece 11-4 onto the pair of workpiece conveying rollers 18 and 19 (see FIG. 3; not shown in FIG. 5), and the process proceeds to step S25.
On the other hand, if the loading confirmation sensor LS2 does not detect the workpiece 11 and the workpiece 11 (11-3) does not exist (step S22 is NO: the state shown in FIG. 14), a new workpiece 11-4 is loaded. It is determined that a part of the condition that can be satisfied is satisfied, and the process proceeds to step S23.
14 and 15, the carry-out side injection device 22 </ b> N injects a cooling medium into the cooling range of the inner peripheral surface of the work 11.

In step S23, it is determined whether or not the carry-in side injection device 21N has returned to a position where it does not interfere with the workpiece 11 being carried (load-in side retracted position). If the carry-in side injection device 21N has returned to the carry-in side retracted position (YES in step S23), even if a new workpiece 11-4 is carried in, it does not interfere with the carry-in side injection device 21N. It is determined that the conditions for carrying in are satisfied, and the process proceeds to step S24.

In step S24, a new workpiece 11-4 is carried into the heat treatment system 200 (state shown in FIGS. 14 and 15). Then, the process proceeds to step S26. The mode of carrying in the workpiece 11-4 is not explicitly shown in FIGS. 14 and 15, but can be performed by, for example, an industrial robot hand (not shown) or other general-purpose devices. In particular, the carry-in device is not limited.
On the other hand, if the carry-in side injection device 21N has not returned to the carry-in side retracted position (step S23 in FIG. 8 is NO), it will interfere with the carry-in side injection device 21N when a new workpiece 11-4 is loaded. It is determined that it is difficult to carry in a new workpiece 11-4. Then, the process proceeds to step S25.
In step S25, the new workpiece 11-4 is not carried into the heat treatment system 200 (the carry-in device 30 is in a standby state), and the process proceeds to step S26.

In step S <b> 26, the control unit 50 determines whether or not to end the work 11 loading work. If the loading work of the workpiece 11 is to be terminated (YES in step S26), the control is terminated as it is.
If the work loading operation is still continued (NO in step S26), the process returns to step S21, and the control from step S21 onward is repeated again.

According to the illustrated embodiment of the present invention, the carry-out confirmation sensor LS1 detects that the hollow cylindrical workpiece 11-1 located closest to the carry-out side has reached the position (the carry-out position) to be carried out. Unless otherwise, the carry-out side air cylinder 22 is extended to move the carry-out side injection device 22N to the position or region where the cooling medium can be injected into the cooling range of the inner peripheral surface of the work 11, and from the carry-out side injection device 22N into the work 11 A cooling medium is injected into the cooling range of the peripheral surface.
In this state, the outer peripheral surface and the outer peripheral portion of the hollow cylindrical workpiece 11 heated by the heating coil 16 at a temperature of, for example, Ac ₃ points or higher and Ac ₃ points + 200 ° C. or lower are Cooling is performed by injecting a cooling medium (including cooling water, cooling oil, air, spray, etc.) from the carry-out side injection device 22N into the cooling range of the inner peripheral surface.

On the other hand, when the carry-out confirmation sensor LS1 detects that the work 11-1 located closest to the carry-out side has reached the position (the carry-out position) to be carried out, the carry-out side injection device 22N enters the retracted state. Before the carry-out side injection device 22N retracts, the cooling medium is injected from the carry-in side injection device 21N into the cooling range of the inner peripheral surface of the work 11, and the inner peripheral surface and the inner peripheral portion of the work 11 are cooled. .
That is, according to the illustrated embodiment of the present invention, the cooling range on the inner peripheral surface of the hollow cylindrical workpiece 11 whose outer peripheral surface and outer peripheral portion are heated (the range including the positions P2 to P3 in FIG. 6). Is always cooled by the cooling medium injected from the carry-out side injection device 22N and / or the carry-in side injection device 21N. Therefore, the inner peripheral surface of the workpiece 11 (the portion between the inner peripheral surface of the workpiece 11 and a position separated from the inner peripheral surface of the workpiece 11 by a distance smaller than 1/2 of the workpiece thickness) and the inner peripheral surface are In the stage before the inner circumference reaches the high temperature tempering temperature due to heat transfer, and before the inner circumference exceeds the low temperature tempering temperature due to heat transfer, the inner circumference and the inner circumference hard Can be secured. Accordingly, the inner peripheral portion and the inner peripheral surface of the work 11 can be prevented from being softened.

Further, according to the illustrated embodiment of the present invention, if the unloading confirmation sensor LS1 detects that the work 11-1 positioned closest to the unloading side has reached the position (unloading position) to be unloaded, The carry-out side air cylinder 22 is contracted, and the tip end portion (load-in side end portion) of the carry-out side injection device 22N is moved to a position (contracted position) that is disengaged from the hollow cylindrical workpiece 11 being conveyed. Therefore, the work 11-1 to be carried out is carried out of the heat treatment system without interfering with the carry-out side injection device 22N.
While the tip end portion (carrying side end portion) of the carry-out side injection device 22N is moved to a position (contracted position) that is disengaged from the hollow cylindrical workpiece 11 being conveyed, the carry-in side air cylinder 21 is extended and loaded. A cooling medium is injected from the side injection device 21N into the cooling range of the inner peripheral surface of the work 11. Therefore, according to the illustrated embodiment, the cooling medium from the carry-out side injection device 22N and / or the carry-in side injection device 21N is always injected in the cooling range of the inner peripheral surface of the workpiece 11. And the hollow cylindrical workpiece | work 11 by which the cooling range of the internal peripheral surface was cooled can be carried out, without interfering with the carrying-out side injection apparatus 22N.
Further, the induction heating from the outer peripheral surface side of the hollow cylindrical workpiece 11 by the heating device 16 and the cooling from the inner peripheral surface side of the hollow cylindrical workpiece 11 are not interrupted each time the cooled workpiece 11 is carried out. Can be done continuously. In other words, according to the illustrated embodiment of the present invention, the cooling from the inner peripheral surface side of the workpiece 11 does not need to be performed in a so-called “batch type”. Therefore, the illustrated embodiment of the present invention can be easily applied to a line that is continuously heat-treated.

In the illustrated embodiment of the present invention, the carry-in confirmation sensor LS2 does not detect the work 11-3 positioned closest to the carry-in side, and the carry-in side air cylinder 21 contracts to bring in the carry-in side injection device 21N. When the tip end portion (unloading end portion) is moved to a position (contracted position) deviated from the hollow cylindrical workpiece 11 being transferred, the new hollow cylindrical workpiece 11-4 is transferred by the loading device 30. It is carried into devices (conveying rollers) 18 and 19. Therefore, when the new work 11-4 is carried into the transport devices (transport rollers) 18 and 19, the new work 11-4 does not interfere with the work 11-3 that is already being transported, and the carry-in side There is no interference with the injection device 21N.
Therefore, not only the unloading but also the loading of a new workpiece 11-4 is guaranteed to continuously operate without stopping the heat treatment system 200.

The illustrated embodiments of the present invention are merely examples, and are not intended to limit the technical scope of the present invention.
In the illustrated embodiment of the present invention, the carry-in side injection device 21N jets the cooling medium after reaching the carry-out side end (see FIG. 10). 11 can be set as the “cooling medium injection start position” as long as the position or region can be injected into the cooling range of the inner peripheral surface.
Similarly, the “cooling medium injection start position” of the carry-out side injection device 22N is not the “carry-in side end”, but the position at which the cooling medium can be injected from the carry-out side injection device 22N to the cooling range of the inner peripheral surface of the workpiece 11 If it is an area, it may be set on a case-by-case basis corresponding to various conditions.

Here, in the illustrated embodiment, the injection devices 21N and 22N are controlled to retreat after stopping the injection of the cooling medium. However, a preferable embodiment for preventing the cooling medium from being scattered around the end. Only. The injection start position of the cooling medium and the injection stop position of the cooling medium are not particularly limited.
In the present invention, induction heating is suitable as the “heating means”, but lasers, ion beams, and the like are also applicable, and the present invention includes these. Furthermore, a heating furnace can be used as a heating means for quenching in the quenching in the first step.

DESCRIPTION OF SYMBOLS 11 ... Work 12, 16 ... Heating coil 13, 17 ... Cooling jacket 14, 15, 18, 19 ... Work conveyance roller 21 ... Carry-in side air cylinder 21N ... Carry-in side injection Device 22 ... Carrying side air cylinder 22N ... Carrying side injection device 23 ... High-pressure air tank 24 ... Carrying side flow path switching valve 25 ... Carrying side flow path switching valve 26, 27 ... Cooling Medium pumping device 30 ... carry-in device 50 ... control means / control unit 200 ... heat treatment system

Claims (6)

In the heat treatment system for hollow cylindrical workpieces that are continuously conveyed,
A transfer device for transferring a hollow cylindrical workpiece;
A heating device for heating the hollow cylindrical workpiece from the outer peripheral surface side;
A cooling device for cooling the hollow cylindrical workpiece from the outer peripheral surface side;
A carry-out side injection device and a carry-in side injection device that inject a cooling medium from the injection port toward the cooling range of the inner peripheral surface of the hollow cylindrical workpiece,
During operation of the heat treatment system, at least one of the carry-in side injection device or the carry-out side injection device is configured to inject the cooling medium toward the cooling range of the inner peripheral surface of the hollow cylindrical workpiece in the cooling region. Characteristic heat treatment system. The heat treatment system includes:
A carry-out side injecting device, a carry-out side injecting device that moves between a carry-out side retreat position that does not interfere with the hollow cylindrical workpiece being conveyed, and a cooling region; and
The carry-in side injection device is provided with a carry-in side retreat position that does not interfere with the hollow cylindrical workpiece being transferred, and a moving device of the carry-in side injection device that moves between the cooling regions,
When carrying out the hollow cylindrical workpiece, the carry-in side injection device is moved to the cooling region, the cooling medium is injected from the carry-in side injection device, and the carry-out side injection device does not interfere with the hollow cylindrical workpiece being transferred. A first function of moving to the side retraction position;
When carrying in a new hollow cylindrical workpiece, the carry-out side injection device is moved to the cooling region, the cooling medium is injected from the carry-out side injection device, and the carry-in side injection device does not interfere with the hollow cylindrical workpiece being transferred. The heat treatment system according to claim 1, wherein the heat treatment system has a second function of moving to a carry-in side retreat position. In the heat treatment method for hollow cylindrical workpieces that are continuously conveyed,
A step of heating the hollow cylindrical workpiece conveyed by the conveying device from the outer peripheral surface side by a heating device;
A step of cooling the hollow cylindrical workpiece conveyed by the conveying device from the outer peripheral surface side by the cooling device;
In the cooling region, injecting the cooling medium from the carry-out side injection device and / or the carry-in side injection device to the cooling range of the inner peripheral surface of the hollow cylindrical workpiece,
In the step of injecting, in the cooling region, at least one of the carry-in side injection device or the carry-out side injection device injects the cooling medium toward the cooling range of the inner peripheral surface of the hollow cylindrical workpiece. . The heat treatment method includes:
A step of moving the unloading-side injection device between the unloading-side retraction position that does not interfere with the hollow cylindrical workpiece being conveyed and the cooling region by the moving device of the unloading-side injection device;
The moving device of the carry-in side injection device has a step of moving the carry-in side injection device between the cooling side and the carry-in side retreat position that does not interfere with the hollow cylindrical workpiece being transferred,
When cooling the cooling range of the inner peripheral surface of the hollow cylindrical workpiece,
When carrying out the hollow cylindrical workpiece, the step of injecting the cooling medium from the carry-in side injection device by positioning the carry-in side injection device in the cooling region, and the interference with the hollow cylindrical shape workpiece being transferred. And having a step of positioning at the unloading side retracted position,
When carrying in a new hollow cylindrical workpiece, the step of injecting the cooling medium from the carry-out side injection device by positioning the carry-out side injection device in the cooling region, and the hollow cylindrical workpiece being conveyed through the carry-in side injection device The heat treatment method according to claim 3, further comprising a step of positioning at a carry-in side retreat position that does not interfere with the load. Perform induction heating of quenching in the first step and quenching in the second step,
In the quenching of the first step, the hollow cylindrical workpiece is continuously fed laterally without any interval, and only from the outer peripheral surface side of the workpiece to Ac ₃ points or more over the entire thickness of the workpiece and Ac ₃ Using the time until the workpiece reaches the cooling section separated from the heating section by induction heating to a temperature below the point + 200 ° C, the workpiece temperature is made uniform in the longitudinal direction and the thickness direction, and the workpiece temperature is Ar ₃ points Before cooling down to cool the workpiece from the outer peripheral side, quench hardening over the entire thickness of the workpiece,
In induction heating for quenching in the second step, the outer peripheral surface and the outer peripheral portion of the workpiece are moved at Ac ₃ points or more from only the outer peripheral surface side of the workpiece while laterally feeding the workpiece that has been quenched and hardened over the entire thickness. And it heats to the temperature below Ac ₃ point +200 degreeC, The heat processing method in any one of Claim 3 and 4 characterized by the above-mentioned. Perform induction heating of quenching in the first step and quenching in the second step,
In the quenching of the first step, the hollow cylindrical workpiece is induction-heated to a temperature of Ac ₃ points or more and Ac ₃ points + 200 ° C. or less over the entire thickness of the workpiece only from the outer peripheral surface side of the workpiece, Immediately after induction heating, cooling is started and the workpiece is cooled only from the outer peripheral surface side, and it is hardened and cured over the entire thickness of the workpiece,
In induction heating for quenching in the second step, the outer peripheral surface and the outer peripheral portion of the workpiece are moved at Ac ₃ points or more from only the outer peripheral surface side of the workpiece while laterally feeding the workpiece that has been quenched and hardened over the entire thickness. And it heats to the temperature below Ac ₃ point +200 degreeC, The heat processing method in any one of Claim 3 and 4 characterized by the above-mentioned.

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