High frequency induction heating device and heating coil change mechanism

Abstract

To provide a stage-changing mechanism of a heating coil capable of performing high-frequency induction heating of a plurality of kinds of axial workpieces having a part of the same shape by using a common heating coil, and to provide a high-frequency induction heating device having the stage-changing mechanism of the heating coil.SOLUTION: At least one of heating coils 5a-5e disposed close to a plurality of positions in the axial direction of the axial workpiece W1 can be retracted to a retracted position away from an induction heating performance position where the induction heating of the axial workpiece W1 can be performed in a direction crossing the axial direction of the axial workpiece W1. The retracted position is a position away from the induction heating performance position in a horizontal direction and a vertical direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a heating coil changing mechanism of a high-frequency induction heating device used when heat treating multiple types of axial workpieces using a common high-frequency induction heating device, and to a high-frequency induction heating device having a heating coil changing mechanism. [Background technology]

[0002] A high-frequency induction heating device (high-frequency hardening device) is a device that consists of a high-frequency power source (high-frequency oscillator) and a tube member made of a good conductor to which high-frequency power is supplied from the high-frequency power source. Consists of The heating coil is equipped with an external electric wiring for passing high-frequency power and an external pipe for circulating and supplying a cooling liquid that suppresses the temperature rise of the heating coil itself by high-frequency induction heating.

[0003] When the heating coil through which high-frequency current is passed is placed close to the surface of the workpiece, a high-frequency induction current is excited on the surface of the workpiece, and the workpiece is high-frequency induction heated. That is, in order to induction heat the workpiece, the heating coil must be close to the surface of the workpiece. Meanwhile, there are various shapes of workpieces, and in order to excite a high-frequency induction current on the surface of the workpiece, it is necessary to prepare a heating coil corresponding to each shape of the workpiece. Then, multiple types of heating coils (heating coil groups) are prepared, and when the workpiece to be heat-treated is determined, the heating coil (heating coil group) corresponding to this workpiece is selected.

[0004] In other words, if the heating coil (heating coil group) used last time is attached to the high-frequency induction heating device, and the heating coil (heating coil group) attached to this high-frequency induction heating device is different from the heating coil (heating coil group) corresponding to the workpiece to be heat-treated this time, it is necessary to first remove the heating coil (heating coil group) currently attached to the high-frequency induction heating device, and then attach to the high-frequency induction heating device the heating coil (heating coil group) corresponding to the workpiece to be heat-treated this time (change of stage or change of setup).

[0005] Patent Document 1 discloses a plurality of replacement units. Each replacement unit is provided with a different type of heating coil. The high-frequency hardening device disclosed in Patent Document 1 is configured such that a replacement unit equipped with a heating coil corresponding to a workpiece to be induction heated (hardened) is disposed in a hardening station, thereby enabling the workpiece to be induction hardened. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-87140 A Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, although the axial workpieces have different lengths, the overall shape of a short axial workpiece may coincide with the shape of a portion of a long axial workpiece. Specifically, the axial workpiece may be a crankshaft, and the overall shape of a three-cylinder crankshaft may correspond to the shape of three of the four cylinders of a four-cylinder crankshaft. That is, three of the four pins (or journals) of a four-cylinder crankshaft may have the same size and shape as the three (all) pins (or journals) of a three-cylinder crankshaft.

[0008] In this case, even if the high-frequency induction heating device has four heating coils (heating coil groups) corresponding to the four pin portions (or journal portions) of a four-cylinder crankshaft, it is not possible to actually use three of the four heating coils to high-frequency induction heat the three pin portions (or journal portions) of a three-cylinder crankshaft.

[0009] The reason for this is that when high-frequency induction heating a short shaft-shaped workpiece, the heating coil, which is not necessary for heat treating the short shaft-shaped workpiece, interferes with the chuck equipped with a center pin and rotational drive mechanism that support both ends of the shaft-shaped workpiece.

[0010] Therefore, in a conventional high-frequency induction heating device (high-frequency hardening device) such as that disclosed in Patent Document 1, it was necessary to provide an exchange unit for each type of axial workpiece, even if the axial workpieces had partially identical external shapes. That is, in the above example, it was necessary to prepare separate heating coil groups for a three-cylinder crankshaft and a four-cylinder crankshaft, and to change the heating coil group corresponding to each axial workpiece of different length (in this case, four heating coils and three heating coils were replaced). As a result, there was a problem that the equipment became large in size.

[0011] Here, in order to prevent the equipment from becoming large, it is conceivable to remove one of the heating coils for the four-cylinder crankshaft from the high-frequency induction heating device when induction heating the three-cylinder crankshaft in the above example. In this case, complicated work is required to attach and detach the heating coil, which takes a considerable amount of time and effort.

[0012] In addition, in the above-mentioned example, when there are three locations to be induction heated, the inventors considered retracting one of the four heating coils that is not being used so as not to interfere with the workpiece or surrounding equipment.

[0013] However, the heating coil is connected to external electric wiring for passing high-frequency current and external piping for circulating and supplying a cooling liquid for cooling the heating coil itself. In order to move an unused heating coil, the heating coil must be moved while the external electric wiring and external piping connected to the heating coil are kept connected. On the other hand, the length of the external electric wiring and external piping cannot be left with much slack. In other words, if the external electric wiring and external piping are left with too much slack, it is necessary to secure a space to accommodate the loose electric wiring and piping. However, in reality, it is difficult to secure such a space. Therefore, the length of the external electric wiring and external piping must be set to a length that can be accommodated in a limited space.

[0014] Furthermore, because the heating coil is connected to external electrical wiring and external piping that are long enough to fit in this limited space, the range of movement of the heating coil is limited, making it difficult to move the heating coil away when not in use.

[0015] Therefore, an object of the present invention is to provide a heating coil change mechanism for a high-frequency induction heating device that can use a common heating coil to perform high-frequency induction heating on multiple types of axial workpieces that have the same partial shape, and also to provide a high-frequency induction heating device having such a heating coil change mechanism.

[0016] The invention described in claim 1 for solving the above problem is a heating coil changing mechanism for a high frequency induction heating device, which has a plurality of heating coils that can approach an upper portion of a shaft-shaped workpiece that is suspended by a suspension mechanism and rotatably supported in a horizontal position by a support mechanism, and can high frequency induction heat a plurality of axial locations of the shaft-shaped workpiece by each of the heating coils, a support mechanism for rotating a pair of rotary support pieces of the axial workpiece downward about a horizontal axis and moving the axial workpiece from the induction heating position to a lower retreat position; a horizontal movement mechanism for moving the heating coil closest to the support mechanism in the induction heating position in a horizontal direction away from a fixed structure; a rotation mechanism for rotating the rotary support pieces by a predetermined angle and lifting the axial workpiece; and a contact member provided at a position higher than a chuck constituting the support mechanism and engaging with a closely facing portion of each of the heating coils that closely faces a heat treatment portion of the axial workpiece, The retreat position is a position separated from the induction heating execution position in the horizontal and vertical directions. The heating coil in the retracted position is a heating coil change mechanism that does not collide with or come into contact with the chuck.

[0017] Generally, changing the stage of a heating coil refers to the operation of replacing a heating coil group arranged at an induction heating position with another heating coil group in a high-frequency induction heating device having multiple heating coil groups, but in the present invention, moving a specific heating coil from an induction heating position to a retracted position, or moving it from a retracted position to an induction heating position, is referred to as "changing the stage."

[0018] In the invention described in claim 1, at least one of the multiple heating coils can be retracted from an induction heating position where the axial workpiece can be induction heated to a retracted position spaced apart in a direction intersecting the axial direction of the axial workpiece. The retracted position of the heating coil is a position spaced apart in the horizontal and vertical directions from the induction heating position. In other words, it is a position spaced apart in an oblique direction from the induction heating position. Therefore, the external electrical wiring and external piping connected to the heating coil are pulled and extended in an oblique direction. On the other hand, the outer shape of the support mechanism that supports the axial workpiece is often curved and has no corners, and there is often a space formed in the support mechanism diagonally to the axial direction of the axial workpiece. Therefore, the heating coil that is retracted to the diagonal retraction position that is separated horizontally and vertically from the induction heating position can easily avoid the support mechanism that supports the axial workpiece. In other words, when high-frequency induction heating shaft-shaped workpieces of different lengths is performed, only the necessary heating coils are used, and the changeover is completed simply by retracting the unnecessary heating coils from the induction heating position to the retracted position. Therefore, there is no need to provide a large-scale changeover device in order to induction heat shaft-shaped workpieces of different lengths. Furthermore, the heating coil, the axial workpiece, the external electric wiring and external piping connected to the heating coil, and the support mechanism for the axial workpiece are not damaged. Since only some of the heating coils are moved from the induction heating position to the retreated position, the heating coils can be changed over extremely quickly. In other words, when a relatively short shaft-shaped workpiece is heat-treated using a high-frequency induction heating device capable of heat-treating a relatively long shaft-shaped workpiece, the changeover can be completed simply by retracting the unnecessary heating coils to the retracted position. In addition, there is no need to attach or detach a specific heating coil to or from the high frequency induction heating device, so no manual labor is required and the changeover does not require time or effort. In other words, the changeover can be performed quickly.

[0019] The invention described in claim 2 is the heating coil stage changing mechanism described in claim 1, characterized in that it has a horizontal movement mechanism that moves at least one heating coil located at the induction heating execution position in a direction in which the horizontal component is greater than the vertical component, and a vertical movement mechanism that relatively moves the heating coil moved by the horizontal movement mechanism in a direction in which the vertical component is greater than the horizontal component.

[0020] The invention described in claim 2 is Since this is a heating coil stage changing mechanism having a vertical movement mechanism that relatively moves the heating coil moved by the horizontal movement mechanism in a direction in which the vertical component is greater than the horizontal component, the heating coil moved by the horizontal movement mechanism can be relatively moved by the vertical movement mechanism in a direction in which the vertical component is greater than the horizontal component. That is, the heating coil can be moved to a retracted position diagonally separated from the induction heating position by the horizontal movement mechanism and the vertical movement mechanism.

[0021] The invention described in claim 3 is a heating coil change mechanism in which the heating coil has a close opposing portion in which the central core of the cross section of the induction heating portion of the axial workpiece closely faces the circumferential surface within a specified angular range of 180 degrees or less, and the abutting portion fits into the close opposing portion of the heating coil to be retracted.

[0022] In the invention described in claim 3, the heating coil has a close facing part that closely faces the circumferential surface of the central core of the cross section of the induction heating part of the axial workpiece within a predetermined angle range of 180 degrees or less, and since the abutting part fits into the close facing part of the heating coil to be retracted, the abutting member fits into the close facing part of the heating coil to be retracted. In other words, the abutting member engages with the heating coil. Therefore, the heating coil is reliably fixed in the retracted position, and the retracted heating coil does not move and collide with surrounding members during high-frequency induction heating, resulting in high safety.

[0023] The invention described in claim 4 is a high-frequency dielectric heating device having the heating coil stage changing mechanism described in any one of claims 1 to 3.

[0024] In the invention described in claim 4, since the heating coil stage changing mechanism described in any one of claims 1 to 3 is provided, stage changing is easy, and the high-frequency induction heating device equipped with the stage changing mechanism can be made smaller. Effect of the Invention

[0025] According to the present invention, the heating coil can be quickly changed over, and the high-frequency induction heating device equipped with the changeover mechanism can be made compact. [Brief description of the drawings]

[0026] [Figure 1]1 is a schematic system diagram of a high-frequency induction heating device according to an embodiment of the present invention. [Diagram 2] 1 is a perspective view of a main part of a high-frequency induction heating device according to an embodiment of the present invention, showing a state in which a coil unit to be retracted for changing is arranged at an induction heating position. FIG. [Diagram 3] 1 is a perspective view of a main part of a high-frequency induction heating device according to an embodiment of the present invention, showing a state in which a coil unit is retracted for changing stages. [Figure 4] FIG. 1 is a front view of the high-frequency induction heating device according to the present embodiment with some parts omitted, in which (a) shows the state in which the coil unit to be retracted for stage change is arranged in the induction heating position, (b) shows the state in which the coil unit to be retracted for stage change has been moved horizontally by the horizontal movement mechanism, and (c) shows the state in which the abutment member has risen from the state in (b) and pushed up the coil unit. [Diagram 5] This is a schematic oblique view of a high-frequency induction heating device according to this embodiment, showing multiple heating coils with integrated disk-type transformers waiting at the induction heating position, and a relatively long axial workpiece being positioned below each heating coil. [Figure 6] 6 is a schematic perspective view of the high-frequency induction heating device according to the present embodiment, showing a state in which a relatively long shaft-shaped workpiece has been moved from below to the induction heating position from the state shown in FIG. 5, and each heating coil is closely opposed to the shaft-shaped workpiece. [Figure 7] This is a schematic oblique view of a high-frequency induction heating device according to this embodiment, showing multiple heating coils with integrated disk-type transformers waiting at the induction heating position, and a relatively short shaft-shaped workpiece being positioned below each heating coil. [Figure 8] 8 is a schematic perspective view of the high-frequency induction heating device according to the present embodiment, showing a state in which one heating coil has been moved horizontally by a horizontal movement mechanism from the state in FIG. 7. [Figure 9]This is a schematic oblique view of the high-frequency induction heating device of this embodiment, showing the state in which the axial workpiece has risen from the state in Figure 8, the heating coils and the axial workpiece are closely opposed to each other, and the heating coils that have moved horizontally engage with the support members and are retreated vertically upward. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The following description will be given with reference to the drawings. As shown in Fig. 1, the high-frequency induction heating device 1 has a high-frequency oscillator 3 that generates high-frequency power from a commercial power source 2, a transformer 4 (4a to 4e) (disk-type transformer), and a heating coil 5 (5a to 5e). Of these, the transformer 4 (4a to 4e) and the heating coil 5 (5a to 5e) comprise a coil unit 6 (6a to 6e). The high-frequency induction heating device 1 performs high-frequency induction heating (high-frequency hardening) on ​​an axial workpiece W1 or W2, which will be described later.

[0028] As shown in FIG. 5, the high-frequency induction heating device 1 actually has a plurality of similar coil units 6a to 6e, and the configuration of the coil unit 6a will be described below, and redundant descriptions of the other coil units 6b to 6e will be omitted.

[0029] As shown in Fig. 1, the high-frequency oscillator 3 has a function of converting AC power supplied from a commercial power source 2 through electrical wiring 17a, 17b into a high-frequency power. The high-frequency oscillator 3 includes output wiring 15a, 15b (external wiring), and contacts 7a, 7b are provided at the tips of the output wiring 15a, 15b. The contacts 7a, 7b are For example, busbars. It constitutes the output terminal of the high-frequency oscillator 3.

[0030] The transformer 4a has a primary side 34a (primary winding) and a secondary side 34b (secondary winding). Contacts 8a, 8b are provided at both ends of the primary side 34a. The contacts 8a, 8b form input terminals of the coil unit 6. Meanwhile, contacts 9a, 9b are provided at both ends of the secondary side 34b. The secondary side 34b is composed of a hollow tubular member made of a good conductor such as copper or a copper alloy. The secondary side 34b is provided with a flexible supply pipe 13a and a discharge pipe 13b, which are external piping.

[0031] The heating coil 5a is a hollow tubular member made of a good conductor such as copper or a copper alloy, and has a bent and / or curved structure. Contacts 10a and 10b are provided at both ends of the heating coil 5a. The heating coil 5a also has a close facing portion 18a. The close facing portion 18a has an arc shape that can be close to and face the heat treatment target portion of the axial workpieces W1 and W2. In this embodiment, the close facing portion 18a has an arc shape (semicircular shape) with a central angle of approximately 180 degrees. Therefore, the close facing portion 18a can be close to and face the circumferential surface of the induction heating target portion (heat treatment target portion) of the axial workpiece W1 (W2) within a predetermined angle range with a central angle of 180 degrees or less in cross section. The heating coil 5a is also connected to a flexible supply pipe 14a and a discharge pipe 14b, which are external piping.

[0032] The contacts of these pipes (wiring) of the high-frequency induction heating device 1 are connected to each other as follows.

[0033] As shown in FIG. 1, contacts 7a, 7b of output wires 15a, 15b of high-frequency oscillator 3 and contacts 8a, 8b (input terminals of coil unit 6) on primary side 34a of transformer 4a are electrically connected.

[0034] Contacts 9a, 9b on the secondary side 34b of the transformer 4a are electrically connected to contacts 10a, 10b of the heating coil 5. Normally, the transformer 4a and the heating coil 5a are integrated as a coil unit 6, and the contacts 9a, 9b and the contacts 10a, 10b are not removed except during maintenance.

[0035] In the high-frequency induction heating device 1 having such a configuration, AC power supplied from a commercial power source 2 is converted into high-frequency power by the high-frequency oscillator 3, and the high-frequency power is output to the primary side 34a of the transformer 4a. In the transformer 4a, the output power is transformed to a predetermined high frequency, and the high-frequency current is passed through the heating coil 5a via the secondary side 34b.

[0036] In reality, the high-frequency induction heating device 1 has a plurality of coil units 6a to 6e of similar configuration, and these coil units 6a to 6e are connected to the high-frequency oscillator 3 in parallel.

[0037] Furthermore, while current is flowing, coolant is supplied from a coolant supply source (not shown) to the secondary side 34b of the transformer 4a of the high-frequency oscillator 3 and the heating coil 5a via supply pipes 13a and 14a, respectively, and the coolant inside each pipe is discharged via discharge pipes 13b and 14b.

[0038] In a state in which the supply pipes 13a, 14a, the discharge pipes 13b, 14b, and the electric wiring 17a, 17b are connected to the high-frequency induction heating device 1, the shaft-shaped workpiece W1 (W2) is high-frequency induction heated.

[0039] As shown in Fig. 4(a), the coil unit 6a is connected to the fixed structure 35 by an electrical wiring group 36 and a piping group 37. The high-frequency oscillator 3 is installed on the fixed structure 35 side. The electrical wiring group 36 includes the output wiring 15a, 15b and contacts 7a, 7b (terminals made of bus bars, for example) shown in Fig. 1. The piping group 37 includes the supply pipes 13a, 14a and the discharge pipes 13b, 14b shown in Fig. 1. In FIG. 4(a), the high-frequency induction heating device 1 is viewed from the front, but a rotation support piece 28b, a center pin 22, and coil units 6b to 6e, which will be described later, are omitted.

[0040] Moreover, the high-frequency induction heating device 1 (high-frequency hardening device) according to this embodiment is provided with cooling jackets 50a-50e (FIG. 5) for each of the coil units 6a-6e. The cooling jackets 50a-50e are provided with a number of nozzles that receive a supply of cooling liquid from the cooling liquid supply source 38 and spray the cooling liquid toward the shaft-shaped workpiece W1 (W2). That is, the cooling jacket 50 is connected to a flexible external pipe that guides the cooling liquid from the cooling liquid supply source 38.

[0041] Furthermore, the high frequency induction heating device 1 has a support mechanism 20 (FIGS. 2 and 5) that supports the shaft-shaped workpiece W1 (W2). The support mechanism 20 includes a base side member 28, a rotation support member 21, and a center pin 22.

[0042] The base side member 28 has a pair of rotation support pieces 28a, 28b. The rotation support pieces 28a, 28b have the same length, and the rotation support pieces 28a, 28b face each other with a distance between them. One end side of the rotation support pieces 28a, 28b is supported by a fixed structure 35 via a bearing, and is rotatable within a predetermined angle range around a horizontal axis 33. The rotation support member 21 is attached to the other end side (free end side) of the rotation support piece 28a. The center pin 22 is attached to the other end side of the rotation support piece 28b.

[0043] The rotation support pieces 28a, 28b rotate synchronously around the horizontal axis 33 by a rotation mechanism (not shown). That is, the rotation support member 21 and the center pin 22 rotate around the horizontal axis 33 while maintaining a state in which they face each other. The rotation support member 21 and the center pin 22 move along a portion of a circular orbit around the horizontal axis 33, but can reciprocate within a predetermined angle range in which the vertical component is larger than the horizontal component.

[0044] The rotation support member 21 has a chuck 23 and a rotation drive unit 24. The rotation drive unit 24 is equipped with a motor and is capable of rotating the chuck 23. The rotation support member 21 is fixed to the other end (free end) side of the rotation support piece 28a.

[0045] The center pin 22 is fixed to the other end (free end) of the rotation support piece 28b. The pivot support pieces 28a, 28b are capable of pivoting within a predetermined angle range around a horizontal axis 33 by a pivot mechanism (not shown).

[0046] The center pin 22 is supported in a cantilever manner by the rotating support piece 28b, and the center of the opposing chuck 23 is disposed on the axis (axial direction) of the center pin 22. An engagement hole for engaging the center pin 22 is provided at one end of the shaft-shaped workpiece W1 (W2), and the center pin 22 engages with this engagement hole. The other end of the shaft-shaped workpiece W1 (W2) is gripped by the chuck 23. That is, the rotation support member 21 and the center pin 22 of the support mechanism 20 are configured so that both ends of the shaft-shaped workpiece W1 (W2) in a horizontal position are supported by the center pin 22 and the chuck 23. The shaft-shaped workpiece W1 (W2) is rotated (spinned) together with the chuck 23 by the rotation drive unit 24.

[0047] The distance between the rotary support member 21 (chuck 23) and the center pin 22 can be adjusted according to the length of the shaft-shaped workpiece W1 (W2). That is, the distance between the two is set by a positioning mechanism (not shown). Alternatively, the shaft-shaped workpiece W1 (W2) held by the chuck 23 is moved so as to approach the center pin 22, the position of which is fixed, and an engagement hole (not shown) of the shaft-shaped workpiece W1 (W2) is engaged with the center pin 22.

[0048] 5, the rotation support member 21 is provided with a protruding portion 26 equipped with a contact member 25. The contact member 25 is a cylindrical member with a diameter slightly smaller than that of the closely facing portion 18a of the heating coil 5a, has rigidity, and protrudes toward the side where the center pin 22 is disposed. The contact member 25 is parallel to the axis of the rotation support member 21. The contact member 25 is disposed above the center line of the center pin 22 and the chuck 23 when the axes (center lines) of the chuck 23 and the center pin 22 reach the induction heating execution position.

[0049] Furthermore, the high frequency induction heating device 1 has a hanging mechanism 30 that suspends and supports the coil units 6a to 6e. The hanging mechanism 30 has a plurality of hanging members 31a to 31e. Each of the hanging members 31a to 31e is equipped with a spring 19 that supports the weight of the coil units 6a to 6e. Each of the hanging members 31a to 31e can suspend each of the coil units 6a to 6e independently so that the coil units 6a to 6e can swing up, down, left, and right.

[0050] In this embodiment, the hanging mechanism 30 includes five hanging members 31a to 31e. A horizontal movement mechanism 32 is provided on the endmost hanging member 31a of the five hanging members 31a to 31e.

[0051] The horizontal movement mechanism 32 has a function of moving the hanging member 31a in a horizontal direction perpendicular to the center line (axis) of the center pin 22 and the chuck 23. In other words, the horizontal movement mechanism 32 can move the hanging member 31a in a direction in which the horizontal component is larger than the vertical component.

[0052] The support mechanism 20 and the horizontal movement mechanism 32 described above constitute a retracting means 45 (FIG. 5) for retracting the coil unit 6a. The retracting means 45 can retract the coil unit 6a to a retracted position that is spaced diagonally upward from the induction heating position. The retracting means 45 can also move the coil unit 6a that has been retracted to the retracted position back to the induction heating position. That is, the retracting means 45 functions as a stage changing mechanism.

[0053] Generally, changing the stage of a heating coil refers to an operation of replacing a heating coil group arranged at an induction heating position with another heating coil group in a high-frequency induction heating device having multiple heating coil groups, but in this embodiment, moving the coil unit 6a from the induction heating position to a retracted position, or moving it from the retracted position to the induction heating position, is referred to as "changing the stage."

[0054] In the following, the induction heating position refers to the position where each of the coil units 6a-6e (heating coils 5a-5e) and the axial workpiece W1 or W2 are disposed when the axial workpiece W1 or W2 is high-frequency induction heated (high-frequency hardened) by each of the coil units 6a-6e (heating coils 5a-5e). That is, the induction heating position of each of the coil units 6a-6e (heating coils 5a-5e) refers to the position where the coil units 6a-6e (heating coils 5a-5e) are disposed to inductively heat the axial workpiece W1 or W2, and is the position closely facing the axial workpiece W1 or W2. Also, the induction heating position of the axial workpiece W1 or W2 refers to the position where the axial workpiece W1 or W2 is induction heated.

[0055] Next, a method for changing the coil unit 6 of the high-frequency induction heating device 1 will be described with reference to FIGS.

[0056] First, when a relatively long shaft-shaped workpiece W1 is heat-treated, both ends of the shaft-shaped workpiece W1 are supported by a rotation support member 21 (chuck 23) and a center pin 22 of a support mechanism 20 located below the induction heating position, as shown in Fig. 5. On the other hand, each of the coil units 6a to 6e is disposed at the induction heating position.

[0057] 4(a), both the electrical wiring group 36 and the piping group 37 hang down. In particular, the piping group 37 hangs down to the point where it almost touches equipment (not shown) on the fixed structure 35 side.

[0058] Next, as shown in Fig. 6, the rotary support pieces 28a, 28b of the base side member 28 of the support mechanism 20 are rotated by a predetermined angle to raise the shaft-shaped workpiece W1 and move the shaft-shaped workpiece W1 to the induction heating position. As a result, the closely facing portions 18a-18e of the heating coils 5a-5e of each coil unit 6a-6e closely face each other at multiple induction heating positions (heat treatment positions) in the axial direction of the shaft-shaped workpiece W1. At this time, the shaft-shaped workpiece W1 pushes up each coil unit 6a-6e slightly, and part of the weight of each coil unit 6a-6e acts on the shaft-shaped workpiece W1.

[0059] Then, in this state, the rotation drive unit 24 is driven, Chuck 23 and the While rotating the shaft-shaped workpiece W1, the coil units 6a-6e are energized (FIG. 1) and high-frequency current is applied to the heating coils 5a-5e (closely facing portions 18a-18e). As a result, each portion of the shaft-shaped workpiece W1 to be heat-treated is heated by high-frequency induction heating and reaches the hardening temperature. Then, the coil units 6a-6e are stopped and a cooling liquid is sprayed from the cooling jacket 50a toward the heated portion of the shaft-shaped workpiece W1 to complete the induction hardening.

[0060] Next, a case will be described in which a relatively long shaft-shaped workpiece W1 that has been subjected to high-frequency induction heating (high-frequency hardening) is replaced with a relatively short shaft-shaped workpiece W2.

[0061] First, the rotating support pieces 28a, 28b of the support mechanism 20 are rotated downward around the horizontal axis 33, and the shaft-shaped workpiece W1 is moved from the induction heating position to a downward retreat position, and then the shaft-shaped workpiece W1 is removed from between the rotating support member 21 and the center pin 22.

[0062] The distance (spacing) between the rotation support member 21 and the center pin 22 immediately after the shaft-shaped workpiece W1 is removed from the support mechanism 20 is longer than the length of the relatively short shaft-shaped workpiece W2. Therefore, the axial position of the center pin 22 is fixed, and the rotation support member 21 is moved in the axial direction (toward the center pin 22), narrowing the gap between the center pin 22 and the rotation support member 21, and supporting both ends of the shaft-shaped workpiece W2 (FIG. 7).

[0063] At this time, if the rotary support piece 28a is rotated about the horizontal axis 33, the chuck 23 will collide with the heating coil 5a. Therefore, as shown in Fig. 8, the horizontal movement mechanism 32 moves the coil unit 6a (heating coil 5a) at the induction heating position in the horizontal direction away from the fixed structure 35. The movement direction of the coil unit 6a (heating coil 5a) at this time is the horizontal direction perpendicular to the axis connecting the rotation support member 21 and the center pin 22, and the horizontal component is larger than the vertical component. Therefore, the horizontal movement mechanism 32 does not substantially lift the coil unit 6a, and the force required to lift the coil unit 6a is not applied to the horizontal movement mechanism 32.

[0064] At this time, the gap between the fixed structure 35 and the coil unit 6a is widened, so that the slackened pipe group 37 is stretched (FIG. 4(b)).

[0065] After the coil unit 6a moves horizontally, the rotating support pieces 28a, 28b are rotated by a predetermined angle by a rotating mechanism (not shown) to raise the shaft-shaped workpiece W2, and as shown in Fig. 9, the contact member 25 engages with the closely facing portion 18a of the heating coil 5a of the coil unit 6a, and further pushes up the coil unit 6a, while the heating coils 5b to 5e of the coil units 6b to 6e closely face each heat treatment target portion of the shaft-shaped workpiece W2. That is, the contact member 25 first contacts the coil unit 6a and pushes up the coil unit 6a, and then the shaft-shaped workpiece W2 is placed at the induction heating position. Therefore, when the chuck 23 moves to the induction heating position, the coil unit 6a has already retreated to the retreat position.

[0066] That is, the rotation support member 21 (chuck 23) and the abutment member 25 are integrated, and when the rotation support piece 28a rotates about the horizontal shaft 33, the two rise together without moving relative to each other. Also, the abutment member 25 is provided at a higher height than the chuck 23. Therefore, when the abutment member 25 engages with the coil unit 6a (the closely facing portion 18a of the heating coil 5a), the chuck 23 has not yet reached a height position where it contacts the coil unit 6a, and the chuck 23 does not collide with or contact the coil unit 6a.

[0067] Since the contact member 25 pushes up the coil unit 6a, even if the chuck 23 rises to the induction heating position, the coil unit 6a has moved further upward, so that the chuck 23 does not come into contact with the coil unit 6a.

[0068] Furthermore, since the coil unit 6a is pushed up by the contact member 25 and moves (rises) in the vertical direction, no load is applied to the horizontal movement mechanism 32.

[0069] The support mechanism 20 rotates the contact member 25 within a predetermined angular range around the horizontal axis 33, and moves the contact member 25 substantially upward or substantially downward. In other words, the support mechanism 20 functions as a vertical movement mechanism that moves the contact member 25 in a direction in which the vertical component is larger than the horizontal component.

[0070] The coil unit 6a is restrained by the engagement (fitting) of the abutment member 25, and is deprived of freedom of movement, and its position is fixed. In other words, the coil unit 6a is prevented from moving during high-frequency induction heating.

[0071] At this time, the gap between the fixed structure 35 and the coil unit 6a has further increased, so that the slackened pipe group 37 is further extended (FIG. 4(c)). In the state shown in FIG. 4(c), the pipe group 37 is slackened by its own weight, but if the coil unit 6a moves any further away from the fixed structure 35, a load will be placed on the pipe group 37 and the coil unit 6a themselves. Therefore, in this embodiment, the state shown in FIG. 4(c) is the state in which the pipe group 37 is maximally extended. In the state shown in FIG. 4(c), there is no contact between the chuck 23 and the coil unit 6a.

[0072] As described above, the high-frequency induction heating device 1 can quickly retract the coil unit 6a from the induction heating position to the retracted position, and move it from the retracted position to the induction heating position. That is, the high-frequency induction heating device 1 can quickly change the coil units 6a to 6e (heating coils 5a to 5e). Therefore, high-frequency induction heating (high-frequency hardening) of the shaft-shaped workpieces W1 and W2 having different lengths can be quickly performed.

[0073] Furthermore, by simply providing the abutment member 25 integrally provided on the rotation drive unit 24 of the support mechanism 20 and the horizontal movement mechanism 32 that moves the coil unit 6a horizontally, it is possible to switch between using and not using the coil unit 6a in response to axial workpieces W1, W2 of different lengths, and the high-frequency induction heating device 1 of this embodiment can achieve significant space savings.

[0074] In this embodiment, an example has been shown in which the horizontal movement mechanism 32 is provided on the hanging member 31a that suspends the coil unit 6a, but the horizontal movement mechanism 32 can also be provided on the hanging member 31e that suspends the coil unit 6e. Specifically, the abutting member 25 is provided integrally with the center pin 22. That is, it is also possible to simultaneously retract the coil units 6a, 6e (heating coils 5a, 5e) on both sides of the multiple coil units 6a to 6e (heating coils 5a to 5e) arranged along the axis of the axial workpiece W1 (W2) from the induction heating implementation position to the retracted position.

[0075] In the present embodiment, the vertical movement mechanism (support mechanism 20) has been described as raising and lowering the retracted heating coil 5a (coil unit 6a) in a predetermined angle range in which the vertical component is greater than the horizontal component in a circular orbit centered on the horizontal axis 33. Alternatively, the vertical movement mechanism may be a mechanism configured with a vertically oriented cylinder that raises and lowers the heating coil 5a. [Explanation of symbols]

[0076] 1 High frequency induction heating device 5a~5e Heating coil 18a Closely facing part of the heating coil to be retracted 20 Support mechanism (vertical movement mechanism) 25 Contact member 30 Suspension mechanism 32 Horizontal movement mechanism 45 Evacuation means (step change mechanism)

Claims

1. A heating coil change mechanism for a high frequency induction heating device, comprising: a plurality of heating coils that can approach an upper portion of a shaft-shaped workpiece that is suspended by a suspension mechanism and rotatably supported in a horizontal position by a support mechanism; and the heating coils can high frequency induction heat a plurality of axial locations of the shaft-shaped workpiece, the heating coils being arranged to a support mechanism that supports the shaft-shaped workpiece, rotates a pair of pivot support pieces that are supported on a fixed structure via bearings downward about a horizontal axis, and moves the pair of pivot support pieces from an induction heating position to a lower retreat position; a horizontal movement mechanism that moves at least one heating coil from the side closest to the chuck constituting the support mechanism in a horizontal direction away from the fixed structure when a shaft-shaped workpiece is present at the induction heating position; A rotation mechanism that rotates the rotation support piece by a predetermined angle to lift the shaft-shaped workpiece; a contact member provided at a position higher than the chuck and engaging with a closely facing portion of each of the heating coils that closely faces a heat treatment portion of the shaft-shaped workpiece; Equipped with A heating coil stage changing mechanism characterized in that the retracted position is a position horizontally and vertically spaced from the induction heating position, and the heating coil in the retracted position does not collide with or come into contact with the chuck.

2. 2. The heating coil stage changing mechanism according to claim 1, further comprising a vertical movement mechanism that relatively moves the heating coil moved by the horizontal movement mechanism in a direction in which the vertical component is greater than the horizontal component.

3. The heating coil has a closely facing portion in which a central core of a cross section of the induction heating portion of the shaft-shaped workpiece closely faces a peripheral surface within a predetermined angle range of 180 degrees or less, 3. The heating coil stage changing mechanism according to claim 2, wherein the contact portion fits into a closely facing portion of the heating coil to be retracted.

4. 4. A high frequency induction heating device comprising the heating coil stage changing mechanism according to claim 1.

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