JPH0628596U - Dummy bar structure of induction heating device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a dummy bar structure of an induction heating device that has a large structural strength without being heated even if it passes through a heating part of the induction heating device. [Structure] Fitting holes 12a are provided on a line in the longitudinal direction at substantially the center of a side wall 12 having a substantially semi-arcuate shape in cross section at regular intervals. The fitting hole 12b is provided on a line inclined by about 60 degrees in one direction along the curved surface from the line connecting the fitting holes 12a, and the direction along the curved surface from the line connecting the fitting holes 12a to each other. The fitting hole 12c is provided on a line inclined by about 60 degrees in the opposite direction. The inner surfaces of the side walls 12 are opposed to each other, and the fitting holes 12 are opposed to each other.
Both ends of the connecting rods 14a, 14b, 14c are fitted into a, 12b, 12c to connect the side walls 12 to each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention, when stopping the operation of an induction heating device that causes electromagnetic induction to heat a workpiece that passes a magnetic field, inserts it into the heating part of the induction heating device, and heats the workpiece from the back. The structure of the dummy bar for pushing out.

[0002]

[Prior art]

 When manufacturing metal parts used in automobiles, etc., they are often manufactured by hot forging. That is, the material is heated and forged while maintaining a high temperature. At this time, an induction heating device is often used as a means for heating the material. In an induction heating device, a coil wound around a cylinder or the like is energized with a high-frequency alternating current to generate a magnetic field inside the cylinder or the like, and electromagnetic induction is generated in a work passing through the inside of the cylinder or the like. The object is being heated, and the cylinder and the like are used as the heating section.

By the way, when the production line is stopped in the factory, the operations of the induction heating device, the forging device, etc. must be terminated. Here, when the operation of the induction heating apparatus is ended, if the operation is ended in a state where the work piece exists inside the heating portion of the induction heating apparatus, the work piece is cooled to room temperature. If the work is heated again during the next operation of the induction heating device, the work may deteriorate and its strength may be reduced. In order to avoid this, it is supposed that the work already inserted into the inside of the heating section should be heated before the operation of the induction heating device is finished. Then, a dummy bar is inserted into the heating unit in order to push out the workpiece already inserted into the heating unit from the rear side.

However, the dummy bar is exposed to the magnetic field when passing through the inside of the heating unit. Therefore, when the dummy bar has a solid structure or has a wall having a large wall thickness even in a hollow structure, the dummy bar is heated by electromagnetic induction. In addition, this dummy bar is pushed out and used many times during the next operation, so it is repeatedly heated. For this reason, the dummy bar deteriorates in a short period of time and its strength becomes small. If the strength is reduced, the dummy bar may be damaged while pushing out the work piece. Therefore, the dummy bar, which has deteriorated to some extent, has been discarded and its life has become relatively short.

In order to prolong the life of the dummy bar, a tube-shaped dummy bar made of a member having a small wall thickness that hardly causes electromagnetic induction has been used. However, the dame bar was not suitable for extruding a work piece because its strength could not be increased due to its structure.

For this reason, as shown in FIG. 4, a cut is made along the generatrix direction in the side wall 1 made of stainless steel having a small wall thickness and in which electromagnetic induction does not easily occur, and a fire resistance is provided inside the side wall 1. A dummy bar 4 formed by packing the material 2 is used. Since the dummy bar 4 is made of stainless steel and has the refractory material 2, it has excellent heat resistance, and since the refractory material 2 is packed inside the side wall 1, the structural strength is sufficiently large.

Further, as shown in FIG. 5, a side wall 6 made of a stainless steel having a small wall thickness that hardly causes electromagnetic induction is provided with an appropriate cut along the generatrix direction, and the inside of the side wall 6 is cut. A dummy bar 8 formed by connecting ribs 7 having a small wall thickness is also used. Since the dummy bar 8 is made of stainless steel, it has excellent heat resistance, and since it has a hollow structure, it is light in quantity and convenient for transportation and the like.

[0008]

[Problems to be solved by the device]

 However, the dummy bars 4 and 8 described above have problems in the following points.

The dummy bar 4 shown in FIG. 4 may collapse due to the brittleness of the refractory material 2, and the life of the dummy bar 4 is not always long. Further, since the refractory material 2 is packed inside the side wall 1, the weight becomes large and the handling such as transportation becomes inconvenient.

Further, in the dummy bar 8 shown in FIG. 5, since the rib 7 has a small wall thickness, the structural strength cannot be increased, and sufficient durability may not be obtained.

Therefore, an object of the present invention is to provide a dummy bar structure of an induction heating device which is structurally large in strength and is not heated even if it passes through a heating part of the induction heating device.

[0012]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the dummy bar structure of the induction heating device according to the present invention pushes the workpiece heated by the heating part of the induction heating device that heats the workpiece by electromagnetic induction from the heating part. In the dummy bar to be inserted into the heating section, side walls having a thickness that does not cause the electromagnetic induction are connected by connecting rods having a thickness that does not cause the electromagnetic induction.

[0013]

[Action]

 When the work is heated by the induction heating device, the work is inserted into a heating part to heat it, and another work is inserted into the heating part from behind to push out the already heated work.

Then, when the operation of the induction heating device is finished, the dummy bar is inserted into the heating portion and the workpiece which has already been heated is pushed out. Since the dummy bar is composed of the side wall and the connecting rod where the electromagnetic induction does not occur, it passes through the inside of the heating unit without being heated to a high temperature. Further, since the side walls of the dame bar are connected to each other by the connecting rod, the dame bar has a structurally sufficient strength and the work piece can be reliably pushed out.

Then, after pushing out the workpiece, the operation of the induction heating device is terminated in a state where the dummy bar is inserted into the heating unit. When the induction heating device is activated again, a new workpiece is inserted into the heating section and the dummy bar is pushed out. The dummy bar is appropriately stored, and is used again when the operation of the induction heating apparatus is stopped, and will be used again and again.

[0016]

【Example】

 Hereinafter, the dummy bar structure of the induction heating device according to the present invention will be described in detail with reference to the illustrated embodiment.

As shown in FIG. 1, in the dummy bar 10, the inner side surfaces of a pair of side walls 12 each having a substantially half-arc shape in a section of a cylinder are opposed to each other, and the side walls 12 are connected to each other by connecting rods 14a, 14b, 14c. It is configured by being fastened with.

The side wall 12 is made of stainless steel having a thickness of about 3 mm, and is provided with fitting holes 12a, 12b, 12c for fitting the connecting rods 14a, 14b, 14c. As shown in FIGS. 1 and 2, the fitting holes 12a are provided at regular intervals on the line extending in the longitudinal direction at substantially the center of the side wall 12. Then, on a line inclined by about 60 degrees in one direction along the curved surface from the line connecting the fitting holes 12a, at a distance substantially equal to the distance between the fitting holes 12a and each fitting hole 12a. The fitting hole 12b is provided at a position that does not coincide with the above in the circumferential direction. In addition, on the line inclined from the line connecting the fitting holes 12a to each other by about 60 degrees in the opposite direction to the above direction along the curved surface, at an interval substantially equal to the interval between the fitting holes 12a and each fitting hole. The fitting holes 12c are provided at positions that do not match the 12a and the fitting holes 12b in the circumferential direction.

The connecting rods 14a, 14b, 14c are made of stainless steel having a diameter of about 3 mm, and the inner surfaces of the side walls 12 are opposed to each other so that the fitting holes 12a, 12b, 12c facing each other are connected to each other. Both ends of the rods 14a, 14b, 14c are fitted to connect the side walls 12 to each other. Therefore, the inclinations of the connecting rods 14a, 14b, 14c are substantially vertical from the end of the dummy bar 10 in the generatrix direction, as shown in FIG. The three kinds of inclinations of the inclined connecting rod 14b and the connecting rod 14c inclined about 60 degrees to the left are repeated in order.

Then, an induction heating apparatus using the above-mentioned dummy bar 10 will be described. In this embodiment, an induction heating device in a production line for hot forging a bar is described.

An induction heating device is arranged immediately before the forging device in the production line. As shown in FIG. 3, a rail 20 for carrying the workpiece 18 is provided above the induction heating device 16. It is set up. An end 20a on the upstream side of the production line of the rail 20 is connected to a work supply device (not shown), and an end 20b on the downstream side of the rail 20 is connected to a forging device (not shown).

Further, a heating part 22 having a heating hole 22a having a substantially circular cross section is continuously arranged above the induction heating device 16, and a lower part inside the heating hole 22a of the heating part 22 is provided. The rail 20 is laid on the rail. The heating part 22 is formed by winding an electric wire around a substantially cylindrical core material having the heating hole 22a to form a coil, and surrounding the coil with an outer wall.

On the rail 20 and on the upstream side of the heating unit 22, there is provided a roller unit 24 for pushing the workpiece 18 into the heating hole 22a of the heating unit 22.

Further, a power supply device for supplying a high-frequency alternating current to a coil inside the heating unit 22 is built in a lower portion of the induction heating device 16.

Here, a procedure for using the dummy bar 10 in the induction heating device 16 described above will be described with reference to FIG.

When each device on the production line is operating, the workpiece 18 is conveyed from the upstream side of the rail 20 of the induction heating device 16. When the workpiece 18 passes through the roller portion 24, it is pushed out to the downstream side. Then, the workpiece 18 is sent to the heating section 22 while being pushed by the workpiece 18 on the upstream side, and at the same time, the workpiece 18 is pushing the workpiece 18 on the downstream side. At this time, a high-frequency alternating current is applied to the coil inside the heating unit 22, a magnetic field is generated inside the heating hole 22a of the heating unit 22, and electromagnetic induction occurs in the workpiece 18. become. The work 18 is heated by the electromagnetic induction, the work 18 is heated to a predetermined temperature while passing through the plurality of heating parts 22, and is extruded from the heating part 22, and then is desired by the forging device. Is forged into the shape of.

By the way, when the production line is stopped, the operation of the induction heating device 16 is terminated. At this time, since the workpiece 18 inserted into the heating unit 22 needs to be completely heated, the dummy bar 10 is inserted from the upstream side of the roller unit 24 while an alternating current is being applied to the coil. The roller 18 is pushed out to the downstream side, and the workpiece 18 is pushed out from the heating portion 22 in a heated state.

Further, after all the workpieces 18 have been pushed out from the heating section 22, the operation of the induction heating apparatus 16 is terminated, and the dummy bar 10 is left inside the heating section 22. Then, when the induction heating device 16 is operated again, the dummy bar 10 is pushed out by the new workpiece 18 inserted into the heating section 22. The pushed-out dummy bar 10 can be appropriately stored and repeatedly used when the operation of the induction heating device 16 is finished.

As described above, according to the present embodiment, the side wall 12 of the dummy bar 10 has a thickness of about 3 mm, and the connecting rods 14a, 14b, 14c have a diameter of about 3 mm. No conduction occurs and no heating occurs. Further, since the side wall 12 and the connecting rods 14a, 14b, 14c are made of stainless steel, the material is excellent in heat resistance. Therefore, even if the dummy bar 10 is heated by heat transfer in contact with the heated workpiece 18, the dummy bar 10 is not deteriorated and a sufficient strength can be maintained. Note that any material other than stainless steel may be used as long as the material has excellent heat resistance and sufficient strength.

Further, as shown in FIG. 2, the inclination of the connecting rods 14a, 14b, 14c is substantially vertical from the end of the dummy bar 10 at a certain interval in the longitudinal direction, inclined by about 60 degrees to the right, and left. The three sidewalls 12 are connected to each other by a regular arrangement of the connecting rods 14a, 14b, 14c. Therefore, the sidewalls 12 are firmly connected to each other, and the strength of the dummy bar 10 can be sufficiently maintained.

In this embodiment, the dummy bar 10 is made of only a single material, but in order to prevent the front and rear end surfaces of the dummy bar 10 from contacting the workpiece 18 and being heated, the dummy bar 10 is not heated. The structure may be such that fire resistance is provided by attaching refractory materials to the front and rear ends of the. When the heated workpiece 18 comes into contact with the front and rear end surfaces of the dummy bar 10, the heat is transferred to the refractory material, but the heat is hardly transferred to the side wall 12 of the dummy bar 10, and the strength of the dummy bar 10 deteriorates. That's not it.

[0032]

[Effect of device]

 As described above, according to the dummy bar structure of the induction heating device of the present invention, the side wall having the thickness that does not cause the electromagnetic induction and the connecting rod having the thickness that does not cause the electromagnetic induction are configured. The dummy bar is never heated. Therefore, the dummy bar is not deteriorated, the life is extended, and the manufacturing cost of the workpiece is reduced.

Further, since the side walls can be connected to each other by an appropriate number of the connecting rods, the structure of the dummy bar becomes strong. For this reason, it is possible to maintain sufficient strength for pushing out the workpiece, and it is not easily damaged.

Further, since the side walls are connected to each other only by the connecting rod, the weight of the dummy bar itself is small. Therefore, the force applied to push out the workpiece is small and sufficient, and normal handling such as transportation and storage becomes easy.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall structure of a dummy bar.

FIG. 2 is a side view showing an end surface of a dummy bar.

FIG. 3 is a front view showing an outline of an induction heating device.

FIG. 4 is a perspective view showing a structure of a conventional dummy bar.

FIG. 5 is a perspective view showing the structure of another conventional dummy bar.

[Explanation of symbols]

 10 Dummy bar 12 Side wall 14a Connecting rod 14b Connecting rod 14c Connecting rod 16 Induction heating device 18 Workpiece 22 Heating part 22a Heating hole

Claims (1)

[Scope of utility model registration request] 1. A dummy bar which is inserted into a heating portion of an induction heating device for heating a workpiece by electromagnetic induction so as to push the workpiece heated from the heating portion, the electromagnetic induction does not occur. A dummy bar structure for an induction heating device, characterized in that side walls having a thickness are connected by connecting rods having a thickness that does not cause electromagnetic induction.