KR20090103620A - Method and Apparatus for Manufacturing Track Bush - Google Patents

Abstract

The present invention relates to a method for producing a track bush and an apparatus thereof. According to the present invention, a first step of charging a track bushing material into a heating furnace, heating it, transferring the cooling bush through a transfer chute branched into a plurality of paths, and then cooling and heat-treating it; A second step of carrying out the high frequency heat treatment only on the outer diameter by transferring the track bushing material to the transporting tray provided with the high frequency heat treatment apparatus after the first step; It includes; step. According to the high frequency heat treatment improvement method of the present invention, while improving the wear resistance and impact resistance compared to the conventional, the trouble of the equipment trouble is solved, there is an advantage that the productivity of the track bush is improved.

Description

Method for manufacturing track bush and apparatus therefor {Method and Apparatus for Manufacturing Track Bush}

The present invention relates to a method and apparatus for manufacturing a track bush, and more particularly, to improve the mechanical properties such as abrasion resistance, strength, toughness and fatigue strength through heat treatment in manufacturing a track bush for use in a tracked vehicle. A method of manufacturing a track bush and an apparatus thereof are provided.

A caterpillar vehicle refers to heavy equipment such as construction heavy equipment, tanks, or tractors. The tracked track chain, which is the driving device of the tracked vehicle, is designed to support the entire equipment by connecting several track shoes continuously connected to each other.

The track shoes are interconnected by track links, which are mounted on the left and right track shoes respectively to interconnect the track shoes. The left track link and the right track link are interconnected by connecting pins.

At this time, the connecting pin is wrapped by the track bush (Bush) in order to prevent wear of the connecting pin. The track bush has a hollow cylindrical shape since a connecting pin must be inserted therein. In other words, a hollow cylindrical track bush is disposed between the track links, and the connecting pin is located at the left. It is mounted through the inside of the hole and the track bush formed in the right track link.

As such, the track bush assembled to the crawler vehicle requires abrasion resistance, impact resistance, toughness, and the like to sufficiently endure various fatigue, impact, tension, and abrasion loads according to the driving environment.

In order to cope with the required quality, the conventional bush is cut and quenched a medium carbon low alloy steel (e.g., medium carbon chromium boron steel) to quench and release the bushing material in the form of a circular pipe, and then again the outer diameter of the bushing material. And a high frequency heat treatment to the inner diameter.

High frequency heat treatment is a method of hardening the surface of a material by rapidly heating and quenching the surface of the material using a high frequency. That is, both the outer diameter and the inner diameter are for obtaining a hardened layer while forming a soft soft zone in the center of the material.

However, in the conventional high frequency heat treatment, as shown in FIG. 1, there is a problem that only a relatively shallow hardened layer can be obtained even when a material having a good degree of quenching is used. Thus, while forming a soft zone in the center portion, the surface heating area is deepened to obtain a deeper hardened layer on the inner and outer diameters of the material, but the heating time becomes longer, and as a result, the temperature becomes too high and the grain size becomes rough. have.

In addition, in the conventional high frequency heat treatment method, in the case of inner diameter heat treatment in which the coil is inserted into the inside of the bush material, the inside of the bush material is narrow, and the coil is frequently touched during the heat treatment of the inner diameter due to the fact that it is difficult to check with the naked eye. Often a failure occurs. In this case, the equipment is stopped and restarted after replacing the coil, which delays the high frequency heat treatment process and leads to a decrease in production.

The present invention is to solve the conventional problems as described above, the object of the present invention is to improve the high-frequency heat treatment method of the bushing material to form a soft zone in the center of the bushing material while the outer diameter and the inner diameter are both deep hardened layer It is to provide a method and apparatus for manufacturing a track bush to obtain a.

Another object of the present invention is to provide a method and apparatus for manufacturing a track bush to prevent equipment trouble by preventing coil defects that may occur in the high frequency heat treatment process.

According to a feature of the present invention for achieving the object as described above, the present invention is charged by heating the material for the track bush to the heating furnace, and transferred to the cooling station through a transfer chute branched in multiple paths to cool the heat treatment A first step; A second step of carrying out the high frequency heat treatment only on the outer diameter by transferring the track bushing material to the transfer tray provided with the high frequency heat treatment apparatus after the first step; And a third step of naturally air-cooling the track bush material subjected to the high frequency heat treatment in the transfer table.

In the second step, the high-frequency heat treatment is a high-frequency heating only on the outer diameter of the track bush material, and at the same time spraying coolant to the inner diameter.

A transfer table for transporting the track bush material; An outer diameter heat treatment device provided on an upper portion of the transfer table so as to be movable upward and downward, and having a ring-shaped heating coil for heating the outer diameter of the track bushing material at a front end thereof with a high frequency; And a coolant injection nozzle provided at a lower portion of the transfer table corresponding to the outer diameter heat processor to move up and down and spraying coolant to the inner diameter of the track bush material.

The heating coil has an inner diameter larger than the outer diameter of the track bush material, and the cooling water injection nozzle has an outer diameter smaller than the inner diameter of the track bush material.

In manufacturing the track bush, high frequency heating is performed only at the outer diameter of the bush material, and at the same time, a high frequency heat treatment is performed to spray cooling water to the outer diameter and the inner diameter of the bush material. As a result, a deep hardened layer is formed on the outer diameter and the inner diameter of the track bush, and a soft zone having a low hardness is formed at the center of the track bush. Thus, impact resistance and toughness can be secured while improving wear life.

 In addition, the present invention omits the conventional inner diameter high frequency heat treatment process. Accordingly, since the internal diameter high frequency device does not need to be provided, production costs are reduced, as well as equipment troubles are solved, and the process is continuously performed, thereby increasing productivity.

1 is a graph showing a curing pattern after the heat treatment of the track bush according to the prior art.

Figure 2 is a block diagram showing a method and apparatus for manufacturing a track bush according to the present invention.

Figure 3 is a cross-sectional view showing a high frequency heat treatment to the outer diameter of the track bush according to an embodiment of the present invention.

Figure 4 is a graph showing a curing pattern after the heat treatment of the track bush according to the present invention.

Explanation of symbols on the main parts of the drawings

10: By heating 20: Transfer suit

30: cooling part 40: carrier

50: high frequency heat treatment device 51: outer diameter heat treatment device

53: heating coil 55: coolant jet nozzle

Hereinafter, a method and a device for manufacturing a track bush according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a configuration diagram showing a method and apparatus for manufacturing a track bush according to the present invention, Figure 3 is a cross-sectional view showing a high-frequency heat treatment to the outer diameter of the track bush according to an embodiment of the present invention, Figure 4 is a present invention Is a graph showing a curing pattern after heat treatment of the track bush.

The method for manufacturing a track bush according to the present invention includes a heat treatment step of performing quenching and annealing of the entire track bush material m (hereinafter referred to as "bush material") after induction heating. After the heat treatment step, the high frequency heat treatment is performed only to the outer diameter of the bushing material (m), characterized in that the annealing treatment.

The bushing material (m) may be a medium carbon chromium boron steel (for example, SCr440B) manufactured in the form of a circular pipe.

As shown in FIG. 2, the track bush loads the track bush-shaped material m cut and plasticized into the heating furnace 10, inductively heats the loaded bushing material m, and induction-heated. A heat treatment step of transferring the material for bushing (m) to the cooling unit 30 through the transfer chute 20 to be quenched and loosened is first performed.

The furnace 10 is an induction furnace 10 for induction heating the material for the bush (m) with electricity, a billet heater (Billet heater) may be employed as the induction furnace (10).

The transfer chute 20 is formed of a steel structure in the form of a pipe or net in the form of a plurality of branches, and the outlet material (m) by sliding the slide energy by the falling energy by placing the outlet at a position lower than the inlet Have it.

The cooling unit 30 allows the entire bushing material m to be uniformly cooled by the cooling water spray. This heat treatment process is carried out for the strength improvement and homogenization of the entire bushing material (m).

The high frequency heat treatment of the present invention is performed on the bushing material m subjected to such a heat treatment step. The high frequency heat treatment is to secure a high strength hardened layer in the inner and outer diameters of the track bush, and is carried out by passing the bushing material m through the feed table 40 provided with the high frequency heat treatment apparatus 50.

The transfer table 40 is disposed in the longitudinal direction on the exit side of the cooling unit 30 and includes a high frequency heat treatment device 50 above and below the transfer table 40. The high frequency heat treatment apparatus 50 includes an outer diameter heat processor 51 and a coolant spray nozzle 55, and the outer diameter heat processor 51 and the coolant spray nozzle 55 face each other or move away from each other based on the feed table 40. It is installed to be movable up and down in the direction.

The outer diameter heat processor 51 has an annular heating coil 53 at its tip. The heating coil 53 is for heating the outer diameter of the bushing material m locally using high frequency and is positioned to surround the outer diameter of the bushing material m by the lowering of the outer diameter heat processor 51. Of course, the heating coil 53 has a larger inner diameter than the outer diameter of the bushing material (m). In this case, the high frequency can be mainly used the frequency of 100-400KHz.

The cooling water injection nozzle 55 is for injecting cooling water to the inner diameter of the bushing material m, and ascends simultaneously with the falling of the outer diameter heat processor 51, and is inserted into the inner diameter of the bushing material m. To this end, the coolant injection nozzles 55 are positioned to form a pair corresponding to the outer diameter heat processor 51. Although not shown, a coolant injection nozzle for injecting coolant to the outer diameter of the bushing material (m) is further provided, and the coolant injection nozzles 55 are a coolant supply pipe (not shown) and a cooling bank (not shown) for supplying coolant. )

When the material m for the bush in the transfer table 40 reaches a predetermined position in the process of being transferred from the inlet side to the outlet side, the outer diameter high frequency heating by the heating coil 53 and the quenching treatment by spraying the coolant are simultaneously performed. do.

That is, as shown in Figure 3, the high frequency heating by the heating coil 53 is made to the outer diameter of the bushing material (m), and at the same time the cooling water is injected to the outer diameter and the inner diameter of the bushing material. This ensures precise martensitic structure by heating for a short time to the outer and inner diameters of the bushing material (m), to have a uniform hardness, as well as to reduce the hardness as it goes to the center.

And, the high-frequency heat treatment is completed for the bushing material (m) while being transferred to the feed table 40, is transferred to a predetermined position through a transfer facility or the like.

Hereinafter, a method of manufacturing a track bush according to the present invention will be described in detail with reference to Examples.

1 and 2, a process of manufacturing the track bush will be described. To this end, first, the material (m) plastically processed in a track bush shape is transferred to the heating furnace 10 and heated, and then transferred to the cooling unit 30 through the transfer chute 20 to be quenched and annealed.

Next, the heat-treated bush material m is transferred to the feed table 40 provided with the high frequency heat treatment apparatus 50. When the bushing material m is transferred and positioned at a position corresponding to the high frequency heat treatment apparatus 50, the outer diameter heat processor 51 and the coolant injection nozzle 55 move in a direction facing each other. In this case, the heating coil 53 is positioned to surround the outer diameter of the bush material m with a predetermined gap, and the cooling water injection nozzle 55 has a predetermined gap with respect to the inner diameter of the bush material m. Is inserted into the state.

And the heating coil 53 and the cooling water injection nozzle 55 is moved up and down with respect to the outer diameter and the inner diameter of the bushing material (m) while heating the high frequency to the outer diameter, and at the same time to spray the coolant to the outer diameter and the inner diameter.

At this time, although not shown, the movement of the outer diameter heat processor 51 and the coolant injection nozzle 55 may be made by the control of the sensor and the controller for detecting the transfer position of the bushing material (m).

In addition, the high frequency heat treatment apparatus 50 performs high frequency heating only on the outer diameter of the bushing material m for a predetermined time, and performs a high frequency heat treatment for spraying cooling water on the outer diameter and the inner diameter at the same time. This process is repeated in the next bushing material (m), the bushing material (m) after the high-frequency heat treatment is natural air-cooled in the process of passing through the feed table 40, and is transferred to a predetermined position by a transfer facility or the like. .

According to such a track bush manufacturing method, as shown in Figure 4, while forming a soft zone in the center, both the outer diameter and the inner diameter can manufacture a track bush obtained a deep hardened layer. This forms a softer soft zone in the center while forming a deeper hardened layer than the conventional hardened layer shown in FIG. 1, thereby improving wear resistance and impact resistance.

Within the scope of the basic technical idea of the present invention, many other modifications are possible to those skilled in the art, and the scope of the present invention should be interpreted based on the appended claims. will be.

Claims (4)

A first step of charging a track bush material by heating it, transferring it to a cooling zone through a transfer chute branched into a plurality of paths, and then cooling and heat-treating it; A second step of carrying out the high frequency heat treatment only on the outer diameter by transferring the track bushing material to the transfer tray provided with the high frequency heat treatment apparatus after the first step; And a third step of naturally air-cooling the track bush material subjected to the high frequency heat treatment in the transfer table. The method of claim 1, In the second step The high frequency heat treatment is a method of manufacturing a track bush, characterized in that the high-frequency heating only the outer diameter of the track bush material, and at the same time to spray the cooling water to the inner diameter. A transfer table for transporting the track bush material; An outer diameter heat treatment device provided on an upper portion of the transfer table so as to be movable upward and downward, and having a ring-shaped heating coil for heating the outer diameter of the track bushing material at a front end thereof with a high frequency; And a coolant injection nozzle provided at a lower portion of the transfer table corresponding to the outer diameter heat processor and configured to move upward and downward, and spraying coolant to the inner diameter of the track bush material. The method of claim 3, wherein The heating coil has an inner diameter larger than the outer diameter of the track bush material, the cooling water injection nozzle has a smaller outer diameter than the inner diameter of the track bush material manufacturing apparatus of the track bush.