JP2019185881A - Induction heating apparatus - Google Patents

Abstract

To provide an induction heating apparatus capable of performing induction heating of the whole region of a short cylinder-shaped workpiece to a target temperature with efficiency and with accuracy, and of changing specifications of a coil with ease.SOLUTION: Provided is an induction heating apparatus 1 that comprises: a coil unit 2 as a heating unit for performing induction heating of a short cylinder-shaped workpiece W to a target temperature; and a power supply 4 that supplies a high-frequency power to the coil unit 2. In the induction heating apparatus 1, the coil unit 2 comprises: a first coil unit 2A that has an outer diameter side coil part 5 arranged at the radial outside of the workpiece W; a second coil unit 2B that has an inner diameter side coil part 6 arranged at the radial inside of the workpiece W; and a frame body 30 that supports both coil units 2A and 2B. The outer diameter side coil part 5 and the inner diameter side coil part 6 are electrically connected in series, and both coil units 2A and 2B are attachable/detachable to/from the frame body 30.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an induction heating device, and more particularly, to an induction heating device that can be suitably used for induction heating of a short cylindrical workpiece having a relatively large axial dimension among annular workpieces.

For example, in a manufacturing process of a machine part made of a steel material such as SUJ2 like a rolling bearing race, heat treatment is performed on a base material (work) of the machine part. This heat treatment is usually performed by quenching and hardening for imparting mechanical strength and hardness to the workpiece, and tempering for the purpose of alleviating residual stress and reducing retained austenite (improving toughness) in the quenched workpiece. Including. The quench hardening treatment and the tempering treatment both include a heating step for heating the workpiece to a target temperature and a cooling step for cooling the heated workpiece. In the heating step, an atmosphere heating furnace or an induction heating device is used. The workpiece is heated. Depending on the steel type (application), mark temperatures in quench-hardening process, for example, it is set to a temperature above the A ₁ transformation point, mark temperatures in tempering treatment is mainly set according to the operating temperature of the machine parts The

  Atmospheric heating furnaces have the advantages of easy temperature control and the ability to heat multiple workpieces at the same time, but they have low energy efficiency and require a lot of time and cost to heat the workpiece to the target temperature. There are disadvantages such as the need for space. For this reason, as a method of heating the workpiece in the heating step, in addition to being able to efficiently heat the workpiece with high energy efficiency, cases of employing induction heating advantageous for downsizing of heat treatment equipment (space saving) are increasing. is there.

  For example, in Patent Document 1 below, when induction heating an annular workpiece, first and second heating coils are coaxially arranged on both sides in the axial direction of the workpiece with an interval therebetween, and the first and second heating coils are arranged. Discloses a technical means for flowing a high-frequency current in the same direction.

JP-A-8-180967

  According to the technical means of Patent Document 1, since the inner and outer diameters and the thickness direction of the workpiece can be heated uniformly, a workpiece with less distortion can be obtained. However, it is assumed that the technical means disclosed in Patent Document 1 is mainly applied when induction heating a thin plate-shaped annular workpiece. Therefore, even if the same technical means is applied when induction heating a short cylindrical workpiece having a relatively large thickness in the axial direction (and radial direction) among annular workpieces, the same effect can be obtained. Not exclusively.

  Thus, when induction heating a short cylindrical workpiece, for example, a method is often employed in which a coil is arranged on the outer side in the radial direction of the workpiece so as to surround the workpiece and the coil is energized. In this case, since the outer diameter side region of the work is first heated, and the inner diameter side region is heated by the heat transfer in the work, the temperature rises in the outer diameter side region and the inner diameter side region of the work. There is a difference in temperature speed (it takes time for the inner diameter area of the workpiece to reach the target temperature). For example, if the amount of power supplied to the coil is increased, the time required for the inner diameter side region of the workpiece to reach the target temperature can be shortened by that amount. Since there is a large difference in the rate of carbide penetration (increase rate of retained austenite) between the inner diameter side region and the inner diameter side region, a high-quality heat-treated product cannot be obtained. For this reason, when the short cylindrical workpiece is induction-heated in the above mode, the power supply amount to the coil is made small so that the difference in heat treatment quality between the outer diameter side region and the inner diameter side region of the workpiece is minimized. I have to set it. In this case, since the heating time of the workpiece becomes long, the heat treatment efficiency and, consequently, the productivity of machine parts are lowered.

  Also, considering the productivity and quality (heat treatment quality) of machine parts, when the workpiece to be heated by the induction heating device is changed to one with a different size, the coil provided in the induction heating device is replaced with the new workpiece. It is desirable that it can be easily changed to specifications (axial dimension, radial dimension, coil pitch, etc.) that allow efficient and accurate heating.

  In view of the above circumstances, the present invention provides an induction heating apparatus that can efficiently and accurately heat the entire short cylindrical workpiece to a target temperature and that can easily change the coil specifications. Objective.

  An induction heating apparatus according to the present invention, which was created to achieve the above object, includes a heating unit for induction heating a short cylindrical workpiece to a target temperature, and a power source for supplying high-frequency power to the heating unit. In the induction heating apparatus, the heating unit is disposed coaxially with the workpiece on the outer side in the radial direction of the workpiece, and includes a first coil unit having an outer-diameter side coil portion that can simultaneously heat each circumferential portion of the workpiece, and the radial direction of the workpiece. A second coil unit that is disposed coaxially with the workpiece on the inside and has an inner diameter side coil portion that can simultaneously heat each circumferential portion of the inner diameter surface of the workpiece, and a frame that supports the first coil unit and the second coil unit. The outer diameter side coil portion and the inner diameter side coil portion are electrically connected in series, and the first coil unit and the second coil unit are detachable from the frame.

  According to the above heating device, the current values (current amounts) flowing through the outer diameter side coil portion and the inner diameter side coil portion that are coaxially disposed on the radially outer side and the radially inner side of the short cylindrical workpiece are made equal. Can do. Therefore, it is possible to simultaneously heat the outer diameter side region and the inner diameter side region of the workpiece under substantially the same conditions, and the heating temperature (heating rate) of the outer diameter side region of the workpiece and the heating temperature of the inner diameter side region of the workpiece ( The difference between the temperature rise rate and the temperature rise rate is less likely to occur. Therefore, the entire area of the short cylindrical workpiece can be induction-heated to the target temperature efficiently and accurately.

  In addition, since the first coil unit having the outer diameter side coil portion and the second coil unit having the inner diameter side coil portion can be attached to and detached from the frame body, the outer diameter side coil portion and / or the inner diameter side coil portion can be removed. Specifications can be easily changed. For this reason, even when the workpiece to be heated is changed, the specification of each coil part can be easily changed to an optimum one for induction heating of the changed workpiece.

  In the above configuration, the first coil unit has an annular portion that constitutes the outer diameter side coil portion, and is a plurality of first coil members that are supported by the frame body so as to be axially movable and detachable with respect to the frame body. And two adjacent first coil members are connected so as to be conductive, and a conductive member detachable from the first coil member can be provided. If it does in this way, the support position and the number of support of the 1st coil member by a frame, ie, the coil pitch and axial direction size of an outside diameter side coil part, can be changed arbitrarily. For this reason, even when the workpiece to be heated is changed, the specification of the outer diameter side coil portion can be easily changed to an optimum one for induction heating of the changed workpiece.

  If the conducting member is formed of a rigid body, the approach and separation movement of the two adjacent first coil members can be restricted. Therefore, it is advantageous in keeping the coil pitch of the outer diameter side coil portion at a predetermined value.

  The 2nd coil unit shall be provided with the 2nd coil member which has the spiral part which constitutes the inner diameter side coil part.

  The induction heating apparatus according to the present invention having the above-described configuration is a short cylindrical workpiece in which it is desired that the entire workpiece is subjected to quench hardening (so-called quenching), such as a bearing ring of a rolling bearing. This can be particularly preferably applied when induction heating to a target temperature.

  The induction heating apparatus according to the present invention can be preferably used not only when the heating process included in the quenching hardening process is performed but also when the heating process included in the tempering process is performed.

  As described above, according to the present invention, an induction heating apparatus that can efficiently and accurately inductively heat the entire short cylindrical workpiece to a target temperature and can easily change the coil specifications is realized. can do. For this reason, it is possible to efficiently and accurately heat various short cylinder-shaped workpieces to a target temperature, thereby efficiently manufacturing high-quality mechanical parts.

It is a whole flowchart of a heat treatment process. It is a partial schematic diagram of an induction heating device concerning one embodiment of the present invention. It is a block diagram which shows typically the electric circuit of an induction heating apparatus. It is a top view when a 1st coil unit is seen from the upper side. FIG. 5 is a cross-sectional view taken along line C-D-E-F in FIG. 4. It is a partial exploded perspective view of the 1st coil unit. It is a partial front view of a 1st coil unit. It is a figure for demonstrating the example of a specification change of an outer diameter side coil part. (A) is a schematic plan view of the second coil unit as viewed from above, and (b) is a right side view of FIG. (A). (A) The figure shows the temperature rise mode of the work when the work is induction-heated by the conventional method, (b) The figure of the work when the work is induction-heated using the induction heating device according to the present invention. It is a figure which shows a temperature rise aspect.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a flowchart of a heat treatment process in which an induction heating apparatus according to an embodiment of the present invention is employed. The heat treatment process includes, for example, a quenching process S1 in which a short cylindrical workpiece W (see FIG. 2) made of steel, such as a base material of an outer ring of a rolling bearing, is quenched and hardened, and a tempered workpiece W is tempered. And a tempering step S2 for performing the treatment. Although illustration is omitted, each of the quenching step S1 and the tempering step S2 includes a heating step for heating the workpiece W to a target temperature and a cooling step for cooling the workpiece W heated to the target temperature. Examples of the steel material include SUJ2 and SUJ3 classified as high carbon chrome bearing steel defined in JIS G4805.

  In FIG. 1, between the quenching step S1 and the tempering step S2, a cleaning step S3 for cleaning the quenched workpiece W, and an inspection whether the cleaned and quenched workpiece W is a non-defective product that satisfies the quality standards. An inspection step S4 to be performed, a cleaning step S5 for cleaning the tempered workpiece W after the tempering step S2, and an inspection for inspecting whether the cleaned tempered workpiece W is a non-defective product satisfying the quality standard. Although step S6 is provided, all of these steps S3 to S6 are not necessarily executed, and some or all of them may be omitted. Although illustration is omitted, after the quenching step S1 and / or tempering step S2, a finishing step for performing a finishing process such as polishing on the workpiece W may be additionally executed.

  Hereinafter, an induction heating apparatus according to an embodiment of the present invention will be described in detail.

  FIG. 2 is a partial schematic view of the induction heating device 1 used for performing the heating step included in the quenching step S1, and FIG. 3 is a block diagram schematically showing an electric circuit of the induction heating device 1. It is. This induction heating apparatus 1 is a coil unit 2 as a heating unit for induction heating the workpiece W to a target temperature, and the workpiece W to be heated in a horizontal posture (a posture in which the central axis is vertically aligned) on the lower side. And a power supply 4 for supplying high-frequency power to the coil unit 2. The coil unit 2 is electrically connected to the power supply 4 via the electrode member 7 and the power distribution members 8a and 8b. Yes.

  As shown in FIG. 2, the coil unit 2 includes a first coil unit 2A and a second coil unit 2B, and a frame body 30 (see FIG. 4; however, in FIG. 4, the second coil is supported by both the coil units 2A and 2B). The unit 2B is not shown). The first coil unit 2A is disposed coaxially with the workpiece W on the outer side in the radial direction of the workpiece W (the workpiece W supported by the workpiece supporting member 3; the same applies hereinafter). It has a heatable outer diameter side coil portion 5. The second coil unit 2 </ b> B has an inner diameter side coil portion 6 that is disposed coaxially with the workpiece W on the inner side in the radial direction of the workpiece W and can simultaneously heat each circumferential portion of the inner diameter surface of the workpiece W.

  4-7, the first coil unit 2A includes a plurality of (two in the illustrated example) first coil members 11 arranged in multiple stages along the axial direction (vertical direction) of the workpiece W; And a conducting member 15. As shown in FIG. 4, the first coil member 11 is formed in a ring shape having an end in the circumferential direction, and includes an annular portion 12 constituting the outer diameter side coil portion 5, and one circumferential end and the other end of the annular portion 12. The first extension portion 13 and the second extension portion 14 extending from the portion are integrally provided. The first coil member is formed by bending or the like of a conductive metal tubular body (for example, a copper tube), and at least the annular portion 12 is located on the same plane (on the horizontal plane) in the circumferential direction. Yes. Then, as shown in FIG. 5, each first coil member 11 is in a horizontal position on the frame body 30 in a state where the central axis of the annular portion 12 is aligned with the central axis of the annular portion 12 of the other first coil member 11. In this embodiment, as shown in FIGS. 2 and 5, the outer-diameter side coil portion 5 is formed by the cooperation of the annular portions 12 arranged at two locations spaced apart from each other in the vertical direction.

  As shown in FIGS. 4 and 5, the frame 30 that supports the first coil unit 2 </ b> A (the first coil member 11 constituting the first coil unit 2 </ b> A) includes a circular pedestal 31 disposed on the lower side of the first coil unit 2 </ b> A, The first coil member 11 is provided at three locations spaced apart in the circumferential direction of the annular portion 12. The first coil member 11 is provided at three locations spaced apart in the circumferential direction of the circular portion 31. It is supported on the frame body 30 (fixed to the support column 32) via the attached support component 33. Each support column 32 is provided with a guide portion 32 a for guiding the first coil member 11 to move up and down. This guide part 32a is comprised by the elongate hole-shaped through-hole extended in the up-down direction. Both the circular pedestal 31 and the support column 32 constituting the frame body 30 are made of an insulating material.

  As shown in FIG. 4, each support component 33 is inserted into the guide portion 32 a of the support column 32, and a bolt member 33 a fastened to a nut 11 a provided at the radially inner end portion on the outer peripheral portion of the annular portion 12. And first and second nuts 33b and 33c that are respectively disposed on the radially inner side and the outer side of the support column 32 and screwed to the bolt member 33a so as to be relatively close to and away from each other.

  With the above configuration, when each of the first coil members 11 moves the nuts 33b and 33c relatively close to each other and clamps the support column 32 in each of the support parts 33 provided at three locations in the circumferential direction, Fixed in place. On the other hand, when the nuts 33b and 33c are relatively moved away from each other in each support component 33 to release the clamping force of the support column 32, the first coil member 11 can be moved up and down. It is possible to adjust the arrangement position and posture of the coil member 11 in the vertical direction. Furthermore, the first coil member 11 can be removed from the frame body 30 by removing the bolt member 33a from the nut 11a in all the support components 33 provided in each first coil member 11. For this reason, the first coil member 11 can be moved up and down with respect to the frame body 30 and is detachable. Further, the first coil unit 2 </ b> A supported by the frame body 30 by fixing the first coil member 11 to the frame body 30 can be attached to and detached from the frame body 30.

  The conductive member 15 shown in FIG. 4 to FIG. 7 connects the first coil members 11 and 11 adjacent to each other so as to be conductive, and similarly to the first coil member 11, a conductive metal tubular body ( For example, a copper tube). The conducting member 15 includes a first head 15a provided at one end in the longitudinal direction, a second head 15b provided at the other end in the longitudinal direction, and a connection portion 15c that connects both the heads 15a and 15b. The first head portion 15a is fixed to the receiving portion 16 provided on the first extension portion 13 of the upper coil member 11 by the bolt member 17, and the second head portion 15b is the lower coil member. 11 is fixed to the receiving portion 16 provided in the second extension portion 14 by a bolt member 17. Thereby, the two coil members 11, 11 adjacent in the vertical direction can be conducted through the receiving portion 16, the bolt member 17, and the conducting member 15.

  The conducting member 15 can be constituted by a flexible electric wire (cable wire) or the like, but if the conducting member 15 made of copper tube is employed as in the present embodiment, the conducting member 15 made of a rigid body. Therefore, there is an advantage that the distance between the adjacent coil members 11 and 11 (the coil pitch of the outer diameter side coil portion 5) can be easily maintained at a predetermined value.

  The coil unit 2 is provided with a cooling circuit for cooling the first coil member 11 (outer diameter side coil portion 5) during energization of the induction heating device 1. If such a cooling circuit is provided, the temperature of the first coil member 11 can be controlled appropriately and efficiently, and the durability of the first coil member 11 can be improved. As shown in FIG. 7, the cooling circuit of the present embodiment communicates the internal spaces of upper and lower adjacent coil members 11 and 11 via a tubular communication member 18 </ b> A and the lowermost (lower) coil member 11. These are formed by connecting a water supply pipe 18B and a drain pipe 18C to the free end and the free end of the uppermost (upper) coil member 11, respectively.

  When the above cooling circuit is adopted, the cooling water supplied from a water storage tank (not shown) is supplied to the internal space of the lower coil member 11 via the water supply pipe 18B as shown by the white arrow in FIG. Then, it flows through the internal space of the communication member 18 </ b> A and the internal space of the upper coil member 11. The cooling water flowing through the inner space of the upper coil member 11 is discharged to the outside through the drain pipe 18 </ b> C connected to the upper coil member 11. As described above, each coil member 11 is cooled by repeatedly circulating the cooling water.

  As shown in FIGS. 2 and 9A and 9B, the second coil unit 2B having the inner diameter side coil portion 6 is formed by bending a conductive metal tubular body (for example, a copper tube). The second coil member 21 is configured. The second coil member 21 includes a spiral portion 22 that has a spiral shape and functions as the inner diameter side coil portion 6, and a first extension portion 23 and a second extension portion 24 that extend from one end and the other end of the spiral portion 22. Have.

  Although not shown, the second coil unit 2B is provided with a cooling circuit for cooling the second coil member 21 during energization of the induction heating device 1. The cooling circuit is formed, for example, by connecting a water supply pipe to the free end of the first extension 23 and connecting a drain pipe to the free end of the second extension 24. If such a cooling circuit is provided, the temperature of the second coil member 21 can be controlled appropriately and efficiently, and the durability of the second coil member 21 can be improved.

  The second coil unit 2 </ b> B (second coil member 21) is detachably supported with respect to the frame body 30. In the present embodiment, one end of a pair of support members 25 and 25 [see FIGS. 9A and 9B] extending in the horizontal direction is fixed to the second coil member 21 and the other ends of the support members 25 and 25 are fixed. The second coil unit 2 </ b> B is supported by the frame body 30 by fixing the nut to the support column 32 of the frame body 30. In this case, the second coil unit 2 </ b> B can be removed from the frame body 30 by removing the nut that fixes the other end of the support member 25 to the column 32.

  As shown in FIG. 2, the outer diameter side coil portion 5 and the inner diameter side coil portion 6 described above are arranged coaxially with the workpiece W to be heated. The work support member 3 is provided so as to be movable up and down along the central axes of the coil portions 5 and 6, a lowered position where the workpiece W to be heated is received and the heated workpiece W is delivered, and the workpiece It reciprocates between the rising position which arrange | positions W between the outer diameter side coil part 5 and the inner diameter side coil part 6.

  The electrode member 7 shown in FIG. 3 has an entrance side electrode 7a and an exit side electrode 7b fixed via an insulating layer. The inlet side electrode 7a is electrically connected to the outer diameter side coil portion 5 (having the first coil unit 2A) via the power distribution member 8a, and the outlet side electrode 7b is connected to the inner diameter side coil portion via the power distribution member 8b. 6 (having the second coil unit 2B). In the present embodiment, as shown in FIGS. 2 and 7, the power distribution member 8a is provided to the receiving portion 16 provided in the first extension portion 13 of the lower first coil member 11 constituting the first coil unit 2A. As shown in FIGS. 2 and 9A and 9B, the power distribution member 8 b is connected to the second extension 24 of the second coil member 21.

  As shown in FIGS. 2 and 3, the first coil unit 2A having the outer diameter side coil portion 5 and the second coil unit 2B having the inner diameter side coil portion 6 are electrically connected in series via the power distribution member 8c. It is connected. In this embodiment, as shown in FIGS. 2 and 7, one end of the power distribution member 8c is connected to the receiving portion 16 provided in the second extension portion 14 of the upper first coil member 11 in the first coil unit 2A. As shown in FIGS. 2 and 9 (a) and 9 (b), the other end of the power distribution member 8c is connected to the second coil member 21 (the first extension 23 thereof) constituting the second coil unit 2B. Yes.

  Although detailed illustration is omitted, the power distribution members 8a to 8c can be formed of a tubular body (rigid body) made of a conductive metal like the coil members 11 and 21 and the conduction member 15, and have flexibility. An electric wire (cable wire) can also be used. Whatever the power distribution members 8a to 8c are used, the power distribution members 8a to 8c are connected to a connection target (the first coil member 11, the second coil member 21, etc.) in a detachable manner.

  From the above, when the induction heating device 1 of the present embodiment is energized (when high frequency power is supplied from the power source 4 to the induction heating device 1), as shown in FIGS. 7a → distribution member 8a → first coil unit 2A having outer coil portion 5 → distribution member 8c → second coil unit 2B having inner coil portion 6 (second coil member 21) → distribution member 8b → exit side A current 9 flows so as to follow the path from the electrode 7b to the power source 4. In the first coil unit 2 </ b> A, the current 9 flows in the order of the lower first coil member 11 → the conductive member 15 → the upper first coil member 11.

  Therefore, as shown in FIG. 2 and FIG. 3, an annular outer ring electrically connected in series to each of the radially outer side and the radially inner side of the workpiece W supported from the lower side in a horizontal posture by the workpiece support member 3. The diameter side coil part 5 and the spiral inner diameter side coil part 6 are arranged coaxially with the workpiece W, and the outer diameter side coil part 5 is energized in that state (high-frequency power is supplied from the power source 4 to the coil unit 2). ) And substantially the same amount of current 9 flows through the outer diameter side coil portion 5 and the inner diameter side coil portion 6. Thus, in the work W, first, the respective circumferential portions (entire area) of the outer diameter surface and the inner diameter surface are induction heated at the same time, and the heated heat of the outer diameter surface and the inner diameter surface is transmitted toward the core portion of the work W. As a result, the entire region is heated.

  In short, if the work W is induction-heated using the induction heating apparatus 1 according to the present invention, the outer diameter side region and the inner diameter side region of the work W can be simultaneously heated under substantially the same conditions. The difference is less likely to occur between the heating temperature (temperature increase rate) of the outer diameter side region and the heating temperature (temperature increase rate) of the inner diameter side region of the workpiece W. Actually, as shown in FIG. 2, the workpiece W was induction-heated while measuring the axial central portion (point A) of the outer diameter surface of the workpiece W and the axial central portion (point B) of the inner diameter surface of the workpiece W. However, as shown in FIG. 10 (b), there is almost no difference between the temperature rising rate at point A and the temperature rising rate at point B, and only the outer diameter side coil portion 5 is used as shown in FIG. 10 (a). Compared with the case where the workpiece W was heated by induction, the point B could be heated efficiently. Therefore, with the induction heating device 1 according to the present invention, the entire area of the short cylindrical workpiece W can be induction-heated to the target temperature efficiently and accurately.

  In addition, in the induction heating device 1 according to the present invention, the first coil unit 2 </ b> A having the outer diameter side coil portion 5 can be attached to and detached from the frame body 30. Further, the first coil unit 2 </ b> A has an annular portion 12 that constitutes the outer diameter side coil portion 5, and a plurality of second coils supported by the frame body 30 in an axially movable and removable state with respect to the frame body 30. One coil member 11 and two first coil members 11 that are vertically adjacent to each other are connected so as to be conductive, and a conductive member 15 that can be attached to and detached from the first coil member 11 is provided. Therefore, the specification of the outer diameter side coil part 5 can be arbitrarily changed by changing the support position and the number of support of the first coil member 11 by the frame body 30.

  A specific example of the specification change will be described with reference to FIG. 8. When the specification shown in the upper part of FIG. 8 is changed to the specification shown in the lower left part of FIG. 8 (a specification in which the coil pitch of the outer diameter side coil portion 5 is expanded). If both the coil members 11 are fixed to the frame body 30 (see FIG. 5) and the two coil members 11 are connected to each other using the conducting member 15 while enlarging the separation distance between the two coil members 11. good. At this time, the conductive member 15 is used in which the length of the connecting portion 15c and the inclination angle with respect to the vertical direction are changed.

  Moreover, the specification shown in the lower center of FIG. 8 from the specification shown in the upper part of FIG. 8 (specification in which the axial dimension of the outer diameter side coil part 5 is expanded without changing the coil pitch of the outer diameter side coil part 5). When the number of the first coil members 11 supported by the frame 30 is increased, the added first coil member 11 and the existing first coil member 11 may be connected using the conductive member 15. . Further, the specification shown in the upper part of FIG. 8 is changed to the specification shown in the lower right part of FIG. 8 (specification in which the coil diameter of the outer diameter side coil part 5 is expanded without changing the coil pitch of the outer diameter side coil part 5). In the case of changing, the first coil member 11 supported by the frame body 30 is removed, and the first coil member 11 having the annular portion 12 having a large diameter dimension is attached and fixed to the frame body 30, and both the coil members 11 are fixed. May be connected using the conductive member 15 so as to be conductive.

  Furthermore, since the second coil unit 2B (second coil member 21) having the inner diameter side coil portion 6 is also detachable from the frame 30, the specification of the inner diameter side coil portion 6 can be arbitrarily changed. it can.

  From the above configuration, in the induction heating device 1 of the present embodiment, the specifications of the outer diameter side coil portion 5 and / or the inner diameter side coil portion 6 can be easily changed. For this reason, even when the workpiece W to be heated is changed, the specifications of the coil portions 5 and 6 can be easily changed to those optimal for induction heating of the changed workpiece W.

  Therefore, the induction heating apparatus 1 according to the present invention can efficiently and accurately inductively heat the entire short cylindrical workpiece W to the target temperature, and the outer diameter side coil section 5 and the inner diameter side for heating the workpiece W. It has the characteristic that the specification of the coil part 6 can be changed easily. For this reason, with the induction heating device 1 according to the present invention, various short cylindrical workpieces W can be efficiently and accurately heated to a target temperature, so that high-quality mechanical parts can be efficiently manufactured. Is advantageous.

  The induction heating apparatus 1 according to the embodiment of the present invention has been described above. However, the induction heating apparatus 1 can be appropriately modified without departing from the gist of the present invention.

  For example, in the embodiment described above, the coil unit 2 having the annular outer diameter side coil portion 5 and the spiral inner diameter side coil portion 6 is employed, but the outer diameter side coil portion 5 is helical. Moreover, the inner diameter side coil portion 6 may be annular. In short, the outer diameter side coil portion 5 and the inner diameter side coil portion 6 are arranged in the circumferential direction of the outer diameter surface and the inner diameter surface of the work W arranged coaxially with the coil portions 5 and 6 when the coil unit 2 is energized. What is necessary is just to be able to heat each part simultaneously (induction heating).

  Further, during the induction heating of the workpiece W, the workpiece W may be rotated around its central axis. Although illustration is omitted, such a configuration can be realized by connecting the work support member 3 shown in FIG. 2 to a rotation drive unit (for example, an electric motor or the like) that rotates around the central axis thereof. . This is advantageous in avoiding variations in the heating temperature at each part in the circumferential direction of the workpiece W, that is, in uniformly heating the entire workpiece W.

  In the above, the induction heating apparatus 1 according to the present invention is used when performing the heating process included in the quenching process S1, but the induction heating apparatus 1 according to the present invention performs the heating process included in the tempering process S2. It can also be used when

  Further, in the above, the technical means according to the present invention is applied to heat-treat the outer ring (base material) of the rolling bearing. The present invention can also be preferably applied to heat treatment of a cage incorporated in a slide bearing, an outer joint member or an inner joint member constituting a constant velocity universal joint, a rolling bearing or a constant velocity universal joint.

  The present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the gist of the present invention. That is, the scope of the present invention is defined by the terms of the claims, and includes the equivalent meanings recited in the claims and all modifications within the scope.

1 Induction heating device 2 Coil unit (heating unit)
2A 1st coil unit 2B 2nd coil unit 4 Power supply 5 Outer diameter side coil part 6 Inner diameter side coil part 7 Electrode member 8a, 8b, 8c Distribution member 9 Current 11 First coil member 12 Annular part 15 Conductive member 17 Bolt member 21 2nd coil member 22 Spiral part 30 Frame 32 Strut 33 Supporting part W Work (short cylindrical work)

Claims (5)

In an induction heating apparatus including a heating unit for induction heating a short cylindrical workpiece to a target temperature, and a power source that supplies high-frequency power to the heating unit,
The heating part is arranged coaxially with the work on the outer side in the radial direction of the work, and includes a first coil unit having an outer diameter side coil part that can simultaneously heat each part in the circumferential direction of the outer diameter surface of the work, and the work A second coil unit that is disposed coaxially with the workpiece on the radially inner side of the workpiece and has an inner diameter side coil portion that can simultaneously heat each circumferential portion of the inner diameter surface of the workpiece, and the first coil unit and the second coil unit. And a frame that supports
The outer diameter side coil part and the inner diameter side coil part are electrically connected in series,
The induction heating apparatus, wherein the first coil unit and the second coil unit are detachable from the frame.   The first coil unit includes a plurality of first coil members that have an annular portion that constitutes the outer diameter side coil portion and are supported by the frame in a state of being axially movable and detachable with respect to the frame. An induction heating device according to claim 1, further comprising: a conductive member that connects the two adjacent first coil members so as to be conductive, and is detachable from the first coil member.   The induction heating device according to claim 2, wherein the conducting member is formed of a rigid body.   The induction heating device according to any one of claims 1 to 3, wherein the second coil unit includes a second coil member having a spiral portion constituting the inner diameter side coil portion.   The induction heating device according to any one of claims 1 to 4, wherein the workpiece is a bearing ring of a rolling bearing.

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