WO2019084941A1 - Induction coil, apparatus and method for eliminating engine valve residual stress - Google Patents

Abstract

An induction coil (6) for eliminating residual stress of an engine valve is disclosed. The induction coil (6) is V-shaped, U-shaped or wave-shaped. The apparatus for eliminating residual stress of an engine valve comprises a frame, a worktable, a heating device and a fixture. The worktable comprises a fixed worktable (1) and a movable worktable (2). The fixed worktable (1) is fixed on the frame, and the movable worktable (2) is mounted on the frame via a feeding device, a feature thereof being that the heating device is mounted on the fixed worktable (1) and comprises an induction heating power supply (4) and the induction coil (6). The induction coil (6) is mounted at an output end of the induction heating power source (4) and is located at the front of a fixing tool of the fixture. The fixture is used to clamp the engine valve and is located on the movable worktable (2) near the induction coil (6). The apparatus has the advantages of uniform heating, a low stress relief temperature, stable elimination of valve residual stress caused by surfacing, and a high rate of product qualification.

Description

Induction coil, device and method for eliminating engine valve residual stress Technical field

The invention relates to the field of valve processing, and in particular to an induction coil, a device and a method for eliminating residual stress of an engine valve.

Background technique

Surfacing technology is a maintenance technique that uses the welding method to strengthen the surface of mechanical parts. It can change the chemical composition and structure of the surface of the part, improve its performance, and extend the service life of the parts. It has important economic value. In order to improve the life of the engine valve sealing surface (ie, the taper surface or the taper surface), it is necessary to weld the hard alloy at the engine valve disc end, but the surfacing technology inevitably brings the residual stress of the surfacing, surfacing welding. The superposition of the residual stress and the stress generated by the external load tends to cause excessive stress in the local region, thereby degrading the structural load bearing capacity. Excessive local stress causes cracks and deformations, which can lead to structural failure when the deformation is too large.

There are many methods for eliminating the residual stress of surfacing, and electromagnetic induction tempering is one of the methods to eliminate the residual stress of surfacing. In the prior art, a ring-like planar coil similar to a mosquito-like scent is often used as an induction coil to heat the valve bottom surface to eliminate the residual stress of the valve surfacing, and the induction coil is located on the same center line as the engine valve, but according to Lenz's law, the ring shape is known. The magnetic induction line of the planar coil is distributed in an annular shape, which overlaps with the direction of the bottom surface of the engine valve. This causes uneven temperature on the bottom surface of the valve head, which is likely to cause local overheating, which leads to overburning of the bottom surface of the valve. Reduced the pass rate of the product. In addition, when the annular planar coil is used, since the annular planar coil blocks the bottom surface of the valve during operation, the temperature measurement of the bottom surface of the valve cannot be realized by infrared temperature measurement, and the bottom surface of the valve is the portion with the highest temperature during heating, thus easily causing Infrared temperature measurement is not accurate, it is difficult to achieve accurate mastery of tempering temperature, and it is easy to cause the metallographic phase of the valve bottom to be unqualified, resulting in low product qualification rate.

Summary of the invention

In order to overcome the existing technical deficiencies, the present invention provides an induction coil for eliminating engine valve residual stress and more uniform electromagnetic induction heating.

The present invention also provides an apparatus and method for eliminating engine valve residual stress using the above-described induction coil.

In order to achieve the object of the present invention, the following technical solutions are implemented:

An induction coil for eliminating residual stress of an engine valve, the induction coil is V-shaped, U Font or wave type.

In the prior art, an annular planar coil similar to a mosquito-like scent is used as an induction coil to heat the bottom surface of the engine valve for tempering, which may cause local overheating of the engine valve, thereby causing over-burning of the valve bottom surface, and the product qualification rate is low; The magnetic induction line of the induction coil is almost in the shape of a line, and the moving direction of the bottom surface of the valve rotates continuously when the valve rotates, so that the bottom surface of the valve is more evenly heated, and the local overheating of the valve is largely avoided. . In addition, the present invention saves coil manufacturing materials and reduces cost compared to conventionally used mosquito-like annular circular coils.

Preferably, the induction coil is W-shaped. Compared with V-shaped and U-shaped induction coils, W-shaped induction coils have higher heating efficiency; while compared with wavy induction coils larger than one W-shaped, heating efficiency is often higher, and control difficulty is relatively large. .

An apparatus for eliminating residual stress of an engine valve, comprising a frame, a workbench, a heating device and a fixture, the workbench comprising a fixed workbench and a movable workbench, the fixed workbench being fixedly mounted on the frame, the activity The workbench is mounted on the frame by the feeding device, and the heating device is mounted on the fixed workbench, including an induction heating power source and the induction coil, and the induction coil is mounted on the output end of the induction heating power source. Located in front of the fixture fixing tool; the clamp is used to clamp the engine valve and is disposed on the movable table near the induction coil.

Further, when heated, the induction coil faces a recessed portion (i.e., a pit) of the underside of the engine valve. When heating, the coil should face the pit of the engine valve, which can make the heating of the pit on the bottom surface of the valve more effective, avoiding the situation that the temperature is not uniform due to insufficient heating of the pit and the tempering effect is not good.

Further, the above apparatus further comprises a temperature measuring device disposed on the fixed working table, the temperature measuring device is close to the bottom surface and the tapered surface of the engine valve for measuring the temperature of the bottom surface and the tapered surface of the engine valve.

Compared with the annular planar coil, the induction coil used in the invention has a small covering area on the bottom surface of the engine valve, and does not affect the temperature of the valve bottom surface of the temperature measuring device. Therefore, the present invention simultaneously measures the temperature on the tapered surface and the bottom surface of the valve, so that It can better monitor the maximum temperature of valve tempering, so as to adjust the heating parameters, effectively eliminate the residual stress of the valve, and will not cause the metallographic phase of the valve bottom to be unqualified, reduce the control difficulty of tempering, and improve the product qualification rate.

A method of using the above-described induction coil to eliminate residual stress of an engine valve includes the following steps:

S1: After the induction heating power supply is stable, use the induction coil to heat the engine valve, so that the valve is quickly added. Heat to stress temperature;

S2: When the engine valve is heated to the stress-removing temperature, the induction coil stops working immediately;

S3: Allow the engine valve to cool naturally.

Further, the frequency range of the induction coil during heating is 10 to 100 KHz, and the power range is 5 to 20 KW.

Further, the destressing temperature ranges from 900 to 1000 °C. In the prior art (using an annular planar coil as an induction coil), stress relief is unstable when the stress-relieving temperature is lower than 1020 °C. However, when the stress-relieving temperature is 1020 ° C, although the residual tensile stress can be eliminated, due to uneven heating, a high-temperature region of the shape of the "thumb nail" appears on the bottom surface of the valve, resulting in quality problems of the product. The present invention effectively reduces the stress-relieving temperature and stabilizes residual stress relief. Preferably, the destressing temperature ranges from 920 to 980 °C. Since the bottom surface is heated uniformly, there is no abnormal precipitation of the "thumb nail" over-burning area and the valve R-position surface.

Further, the distance between the thermal induction coil and the bottom surface of the engine valve is 1 to 5 mm.

Compared with the prior art, the present invention has the following beneficial effects:

(1) According to the valve characteristics and Lenz's law, the invention designs an induction coil for eliminating the residual stress of the engine valve. The coil structure is simple, the heating is uniform, and the manufacturing process of the coil is simple, saving a large amount of manufacturing materials and reducing the number of manufacturing materials. manufacturing cost.

(2) The present invention also provides an apparatus and method for eliminating residual stress of an engine valve by using the above-mentioned induction coil, which can stably eliminate residual stress after valve surfacing and realize optimization of metallographic structure; The heating is more uniform, no over-burning occurs, and the stress-relieving temperature is lowered, and no precipitation occurs on the surface of the R-position.

DRAWINGS

Figure 1 is a schematic view of a W-shaped coil;

2 is a schematic structural view of an apparatus for eliminating residual stress of an engine valve.

Detailed ways

The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

Example

The embodiment provides an induction coil for eliminating residual stress of an engine valve, and the induction coil is V-shaped, U-shaped or wave-shaped. It is preferably W-shaped as shown in FIG.

As shown in FIG. 2, the embodiment further provides an apparatus using the above induction coil, comprising a frame, a worktable, a heating device, a fixture and a control device, and the worktable comprises a fixed worktable 1 and a movable worktable 2 The fixed workbench 1 is fixedly mounted on the frame, and the movable workbench 2 is mounted on the frame by the feeding device. The heating device is mounted on the fixed worktable 1, and includes an induction heating power source 4 and an induction coil 6. The induction coil 6 is mounted at an output end of the induction heating power source 4 and located in front of the fixture fixing tool; the fixture is used for clamping an engine valve and is disposed on the movable table 2 at a position close to the induction coil. The control device is a control box 17.

Among them, the induction coil is V-shaped, U-shaped or wave-shaped. It is preferably W-shaped.

The stationary workbench 1 is provided with a water-cooling circulation system 3 and an infrared temperature measuring device 7, and the water-cooling circulation system 3 extends into the induction heating power source 4 through the circulating water pipe 15 to water-cool the induction heating power source 4; the infrared temperature measuring device 7 is fixedly mounted on the The stationary table 1 is connected to the control box 17, and the thermal sensor is located near the coil 6 for measuring the temperature of the engine valve bottom surface and the tapered surface.

The movable table 2 is located side by side with the stationary table 1, and has a guide rail 22 matched with it and having a dovetail groove. The movable table 2 is connected with a feeding device including a feeding cylinder 21 connected to the movable table 2 and an electrically controlled directional control valve connected to the feeding cylinder 21 for controlling the feeding and retracting of the feeding cylinder 20. The control box 17 is connected to the electronically controlled directional control valve 20.

The clamp for clamping the engine valve port includes a support clamp 12, a pressure roller 8, a fork bracket 18, a pneumatic cylinder 9, a transmission mechanism, and a power source. Wherein, the support fixture 12 is disposed on the movable workbench 2 adjacent to the induction coil 6 and facing the induction coil 6, the upper end of which is a notch groove for placing the middle shaft of the valve, the lower end is a mounting seat; the "fork" of the fork bracket 18 Connected to the pinch roller 8 through a central shaft, the "fork handle" of the fork bracket 18 is connected to the cylinder 9; the notch of the notch groove is opposite to the pinch wheel 8, and the central axis of the pinch wheel 8 is placed in the notch groove The central axis of the valve is parallel. The transmission mechanism is composed of a universal joint 13 and a reduction gear box 14. The power source thereof is an electric motor 10, and the electric motor 10 is connected to the input end of the reduction gear box 14, and the output end of the reduction gear box 14 is connected to one end of the universal joint 13 The other end is connected to the central axis.

A method of using the above-described induction coil to eliminate residual stress of an engine valve includes the following steps:

S1: After the induction heating power supply is stable, the engine valve is heated by the induction coil to quickly heat the valve to the stress-free temperature;

S2: When the engine valve is heated to the stress-removing temperature, the induction coil stops working immediately;

S3: Allow the engine valve to cool naturally.

Among them, the frequency range of the induction coil during heating is 10 to 100 KHz, and the power range is 5 to 20 KW. The stress-relieving temperature ranges from 900 to 1000 °C. Preferably, the destressing temperature ranges from 920 to 980 °C.

Specifically, during operation, the machine-operated reversing valve 19 controls the cylinder 9 to feed, the control cylinder 9 and the pinch roller 8 pressurize the engine valve 11 when propelling, and releases the engine valve 11 when evacuating: the electronically controlled reversing valve 20 controls The cylinder 21 is advanced or evacuated according to a signal from the control box 17, even if the movable table 2 moves along the guide rail 16; the specific working process is as follows:

(1) starting the water cooling circulation system 3, and conveying the cold water to the induction heating power source 4;

(2) starting the induction, such as the thermal power source 4, and causing the induction coil 6 to generate magnetic induction through the power output device 5; the cold water takes away the heat generated by the power supply module and the induction coil 6 by sensing the internal conduit of the thermal power source 4;

(3) The motor 10 is started by the control box 17, and the motor 10 drives the universal joint 13 through the reduction gear box 14, and the universal coupling 13 drives the compression wheel 8 to rotate: the engine valve 11 is placed on the support fixture 12. The starting cylinder 9 is longitudinally inserted into the pressing wheel 8, so that the pressing wheel 8 and the bearing clamp 12 press the rod portion of the engine valve 11 and drive the engine valve 11 to rotate;

(4) After the above steps are completed, the control box 17 automatically controls the lateral movement of the movable table 2, advances the rotating engine valve 11 toward the induction coil 6, and directly inductively heats the proximity induction coil 6, and the engine valve portion begins to heat up. Red, the rotation is to ensure the uniformity of heat: when the engine valve 11 is heated to a prescribed temperature, the infrared temperature measuring device 7 issues a command to the control box 17 when the set temperature is detected, and the control box 17 receives After the signal, the instruction of the movable table 2 is retracted, and then the movable table 2 is withdrawn, the cylinder 9 is retracted to drive the pressing wheel 8 to be released; the engine valve 11 is placed in the cooling basket for natural cooling, and one working cycle is completed.

Wherein, in the step (4), when the induction heating is performed, the distance between the heat induction coil and the bottom surface of the engine valve is preferably 1 to 5 mm.

Preferably, in order to ensure heating uniformity, the copper tube of the induction coil 6 faces the pit on the bottom surface of the valve.

The above embodiments are merely illustrative of the invention and are not intended to limit the embodiments of the invention. Other variations or modifications of the various forms may be made by those skilled in the art in light of the above description. There is no need and no way to exhaust all of the implementations. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in Within the scope of the claims of the present invention.

Claims (10)

An induction coil for eliminating residual stress of an engine valve, characterized in that the induction coil is V-shaped, U-shaped or wave-shaped. The induction coil for eliminating residual stress of an engine valve according to claim 1, wherein the induction coil has a W shape. An apparatus for eliminating residual stress of an engine valve, comprising a frame, a workbench, a heating device and a fixture, the workbench comprising a fixed workbench and a movable workbench, the fixed workbench being fixedly mounted on the frame, the activity The workbench is mounted on the frame by the feeding device, wherein the heating device is mounted on the fixed workbench, including an induction heating power source and the induction coil according to any one of claims 1 to 2, The induction coil is mounted at an output end of the induction heating power source and located in front of the fixture fixing tool; the clamp is used for clamping an engine valve and is disposed on a movable table near a position of the induction coil. The apparatus for eliminating residual stress of an engine valve according to claim 3, wherein said induction coil faces a recessed portion of a bottom surface of the engine valve when heated. The apparatus for eliminating engine valve residual stress according to claim 3 or 4, further comprising a temperature measuring device disposed on the fixed table, the temperature measuring device being close to the bottom surface and the tapered surface of the engine valve for measuring the engine The temperature of the bottom and tapered surfaces of the valve. A method for eliminating engine residual stress by using the induction coil of any one of claims 1 to 2, comprising the steps of: S1: After the induction heating power supply is stable, the engine valve is heated by the induction coil to heat the engine valve to the destressing temperature; S2: When the engine valve is heated to the stress-removing temperature, the induction coil stops working immediately; S3: Allow the engine valve to cool naturally. The method for eliminating residual stress of an engine valve according to claim 6, wherein the frequency range of the induction coil during heating is 10 to 100 kHz, and the power range is 5 to 20 KW. A method of eliminating engine valve residual stress according to claim 6 or claim 7, wherein said stress relief temperature ranges from 900 to 1000 °C. A method of eliminating residual stress of an engine valve according to claim 8, wherein said stress relief temperature ranges from 920 to 980 °C. A method of eliminating residual stress of an engine valve according to claim 6 or 7 or 9, wherein Therefore, the distance between the thermal induction coil and the bottom surface of the engine valve is 1 to 5 mm.

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