JP7175621B2 - induction heating device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating apparatus, and more particularly, to an induction heating apparatus that can be suitably used for induction heating a short cylindrical workpiece having a relatively large axial dimension among annular workpieces.

For example, in the manufacturing process of a machine part made of steel such as SUJ2, such as a bearing ring of a rolling bearing, heat treatment is applied to the base material (work) of the machine part. This heat treatment usually consists of quench hardening treatment to impart mechanical strength and hardness to the workpiece, and tempering treatment for the purpose of relieving residual stress and reducing retained austenite (improving toughness) in the quenched workpiece. including. Both the quench hardening treatment and the tempering treatment include a heating step of heating the workpiece to a target temperature and a cooling step of cooling the heated workpiece. Work is heated. Although it depends on the type of steel (application), the target temperature in quench hardening treatment is set, for example, to _a temperature exceeding the A1 transformation point, and the target temperature in tempering treatment is mainly set according to the operating temperature of the machine part. be.

Atmospheric heating furnaces have advantages such as easy temperature control and the ability to heat multiple workpieces at the same time. There are disadvantages such as the need for space. For this reason, as a method for heating the work in the above heating process, induction heating, which has high energy efficiency and can efficiently heat the work, and is advantageous for downsizing (saving space) of heat treatment equipment, is increasingly being used. be.

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 a gap therebetween, and the first and second heating coils A technical means is disclosed in which a high-frequency current is passed in the same direction.

JP-A-8-180967

According to the technical means of Patent Document 1, it is possible to uniformly heat the inner and outer diameters and the thickness direction of the work, so that it is possible to obtain a work with less distortion. However, the technical means disclosed in Patent Literature 1 is mainly intended to be applied to the induction heating of thin-plate annular workpieces. Therefore, even if the same technical means are applied to the induction heating of short cylindrical workpieces that are relatively thick in the axial direction (and radial direction) among annular workpieces, the same effects can be obtained. Not exclusively.

Therefore, when a short cylindrical work is induction-heated, for example, a method of arranging a coil radially outside the work so as to surround the work and energizing the coil is often adopted. In this case, the workpiece is first heated in the outer diameter side area, and the inner diameter side area is heated by the accompanying heat transfer within the workpiece. A difference occurs in the temperature speed (it takes time for the inner diameter side region of the work 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 area of the workpiece to reach the target temperature can be shortened by that amount, but the temperature rise of the outer diameter side area of the workpiece can be shortened by that amount. Since there is a large difference in the dissolution rate of carbides (increasing rate of retained austenite) between the inner diameter side region and the inner diameter side region, it becomes impossible to obtain a high-quality heat-treated product. Therefore, when a short cylindrical work is induction-heated in the above manner, the amount of power supplied to the coil is reduced so that the difference in heat treatment quality between the outer diameter side region and the inner diameter side region of the work becomes as small as possible. I have no choice but to set it. In this case, the workpiece is heated for a long time, so that the heat treatment efficiency and the productivity of the machine parts are lowered.

In addition, considering the productivity and quality (heat treatment quality) of machine parts, if the workpiece to be heated by the induction heating device is changed to a different size, the coil provided in the induction heating device will be replaced with the changed workpiece. It is desirable to be able to easily change the specifications (axial dimension, radial dimension, coil pitch, etc.) that allow efficient and accurate heating.

In view of the above circumstances, it is an object of the present invention to provide an induction heating apparatus capable of efficiently and accurately induction-heating the entire area of a short cylindrical workpiece to a target temperature, and capable of easily changing coil specifications. aim.

An induction heating apparatus according to the present invention, which has been devised to achieve the above object, includes a heating section for induction heating a short cylindrical workpiece to a target temperature, and a power supply for supplying high-frequency power to the heating section. In the induction heating device, the heating portion includes a first coil unit having an outer diameter side coil portion arranged coaxially with the work radially outwardly of the work and capable of simultaneously heating each part in the circumferential direction of the work; A second coil unit which is arranged coaxially with the work inside and has an inner diameter side coil portion capable of simultaneously heating each part in the circumferential direction of the inner diameter surface of the work, and a frame supporting 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 value (current amount) flowing through the outer diameter side coil portion and the inner diameter side coil portion coaxially arranged on the radially outer side and the radially inner side of the short cylindrical work, respectively, is made equal. can be done. Therefore, it is possible to simultaneously heat the outer diameter side area and the inner diameter side area of the work under substantially the same conditions, and the heating temperature (heating rate) of the outer diameter side area of the work and the heating temperature (heating rate) of the inner diameter side area of the work ( temperature rise rate). Therefore, the entire area of the short cylindrical work can be efficiently and accurately induction-heated to the target temperature.

In addition, since the first coil unit having the outer coil portion and the second coil unit having the inner coil portion are detachable from the frame, the outer coil portion and/or the inner coil portion Specifications can be easily changed. Therefore, even when the work to be heated is changed, the specifications of each coil can be easily changed to the optimum one for induction heating the changed work.

In the above configuration, the first coil unit has an annular portion forming an outer diameter side coil portion, and is supported by the frame in a manner that it can move in the axial direction and be attached to and detached from the frame. and a conductive member that electrically connects two adjacent first coil members and is detachable from the first coil member. In this way, the support position and the number of the first coil members supported by the frame, that is, the coil pitch and the axial dimension of the outer diameter side coil portion can be arbitrarily changed. Therefore, even when the work to be heated is changed, the specification of the outer diameter side coil portion can be easily changed to the optimum one for induction heating the changed work.

If the conducting member is made of a rigid body, it is possible to restrict the movement of the two adjacent first coil members toward and away from each other. Therefore, it is advantageous in keeping the coil pitch of the outer diameter side coil portion at a predetermined value.

The second coil unit may include a second coil member having a spiral portion forming the inner diameter side coil portion.

The induction heating apparatus according to the present invention having the above configuration is a short cylindrical workpiece, such as a bearing ring of a rolling bearing, for which the entire workpiece is desired to be quench hardened (so-called through quenching). can be particularly preferably applied when performing induction heating to a target temperature.

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

As described above, according to the present invention, it is possible to efficiently and accurately induction-heat the entire area of a short cylindrical workpiece to a target temperature, and to realize an induction heating apparatus capable of easily changing the coil specifications. can do. Therefore, it is possible to efficiently and accurately heat various short cylindrical workpieces to a target temperature, thereby efficiently manufacturing high-quality machine parts.

FIG. 2 is an overall flow chart of a heat treatment process; 1 is a partial schematic diagram of an induction heating device according to an embodiment of the present invention; FIG. It is a block diagram which shows the electric circuit of an induction heating apparatus typically. It is a top view when a 1st coil unit is seen from an upper side. FIG. 5 is a cross-sectional view taken along line CDEF in FIG. 4; 4 is a partially exploded perspective view of the first coil unit; FIG. It is a partial front view of a 1st coil unit. It is a figure for demonstrating the example of specification change of an outer diameter side coil part. (a) is a schematic plan view when the second coil unit is viewed from above, and (b) is a right side view of (a). (a) shows the temperature rise of the work when the work is induction-heated by a conventional method, and (b) shows the work when the work is induction-heated using the induction heating apparatus according to the present invention. It is a figure which shows a temperature rise aspect.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a flow diagram of a heat treatment process employing an induction heating apparatus according to an embodiment of the present invention. The heat treatment process includes, for example, a quenching step S1 in which a short cylindrical work 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 the quenched work W is tempered. and a tempering step S2 for applying a treatment. Although not shown, the quenching step S1 and the tempering step S2 each include a heating step of heating the workpiece W to a target temperature and a cooling step of cooling the workpiece W heated to the target temperature. Examples of the steel materials include SUJ2 and SUJ3, which are classified as high carbon chromium bearing steels defined in JIS G4805.

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

An induction heating device according to an embodiment of the present invention will be described in detail below.

FIG. 2 is a partial schematic diagram of the induction heating device 1 used to perform 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. is. This induction heating apparatus 1 includes a coil unit 2 as a heating unit for induction heating a work W to a target temperature, and a work 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 power distribution members 8a and 8b. there is

As shown in FIG. 2, the coil unit 2 includes a first coil unit 2A, a second coil unit 2B, and a frame 30 (see FIG. 4) that supports the coil units 2A and 2B. Illustration of the unit 2B is omitted.). The first coil unit 2A is arranged radially outward of the work W (the work W supported by the work support member 3; the same shall apply hereinafter) coaxially with the work W, and simultaneously It has a heatable outer diameter side coil portion 5 . In addition, the second coil unit 2B has an inner diameter side coil portion 6 which is arranged coaxially with the work W inside the work W in the radial direction, and which can simultaneously heat each part of the inner diameter surface of the work W in the circumferential direction.

As shown in FIGS. 4 to 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 work W, and a conducting member 15 . As shown in FIG. 4 , the first coil member 11 has a ring-like shape with ends in the circumferential direction. It integrally has a first extension portion 13 and a second extension portion 14 extending from the portion. The first coil member is formed by curving a tubular body (for example, a copper tube) made of a conductive metal, and at least the annular portion 12 has its circumferential portions positioned on the same plane (on the horizontal plane). there is As shown in FIG. 5, each first coil member 11 is placed horizontally on the frame 30 with the central axis of the annular portion 12 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 cooperation of the annular portions 12 arranged at two vertically spaced locations.

As shown in FIGS. 4 and 5, the frame 30 that supports (the first coil member 11 that constitutes) the first coil unit 2A includes a circular base 31 arranged below the first coil unit 2A, Supports 32 are erected at a plurality of locations (three locations in this embodiment) spaced apart in the circumferential direction of the circular pedestal 31, and the first coil member 11 is provided at three locations spaced apart in the circumferential direction of the annular portion 12. It is supported by the frame 30 (fixed to the struts 32) via the attached support parts 33. As shown in FIG. Each post 32 is provided with a guide portion 32 a for guiding the vertical movement of the first coil member 11 . The guide portion 32a is composed of an elongated through hole extending in the vertical direction. Both the circular pedestal 31 and the pillars 32 that constitute the frame 30 are made of an insulating material.

As shown in FIG. 4 , each support member 33 has a bolt member 33 a fastened to a nut 11 a provided on the outer peripheral portion of the annular portion 12 at its radially inner end while being inserted into the guide portion 32 a of the column 32 . , and first and second nuts 33b and 33c that are disposed radially inside and outside the strut 32, respectively, and are screwed onto the bolt member 33a so as to move toward and away from each other.

With the above configuration, each of the first coil members 11 can be vertically moved when the nuts 33b and 33c are relatively moved closer to each other to clamp the column 32 in each of the support parts 33 provided at three locations in the circumferential direction. Fixed in place. Conversely, when the nuts 33b and 33c of the supporting parts 33 are relatively moved away from each other to release the clamping force of the column 32, the first coil member 11 can be vertically moved. It is possible to adjust the arrangement position and attitude of the coil member 11 in the vertical direction. Furthermore, the first coil member 11 can be removed from the frame 30 by removing the bolt member 33a from the nut 11a in all the support parts 33 provided on each first coil member 11 . Therefore, the first coil member 11 can be moved up and down with respect to the frame 30 and can be attached and detached. Also, the first coil unit 2</b>A supported by the frame 30 by fixing the first coil member 11 to the frame 30 is detachable from the frame 30 .

The conductive member 15 shown in FIGS. 4 to 7 connects the vertically adjacent first coil members 11, 11 so as to be conductive, and is made of a conductive metal tubular body ( copper tube). The conducting member 15 has a first head portion 15a provided at one end in the longitudinal direction, a second head portion 15b provided at the other end in the longitudinal direction, and a connecting portion 15c connecting the two heads 15a and 15b. The first head portion 15a is fixed by a bolt member 17 to the receiving portion 16 provided on the first extension portion 13 of the upper coil member 11, and the second head portion 15b is attached to the lower coil member. It is fixed by a bolt member 17 to a receiving portion 16 provided on the second extension portion 14 of 11 . As a result, two vertically adjacent coil members 11 , 11 can be electrically connected via the receiving portion 16 , the bolt member 17 and the conducting member 15 .

The conductive member 15 can be composed of a flexible electric wire (cable wire) or the like. Therefore, there is an advantage that the distance between the adjacent coil members 11, 11 (coil pitch of the outer diameter side coil portion 5) can be easily kept 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 ) while the induction heating device 1 is energized. By providing such a cooling circuit, the temperature of the first coil member 11 can be appropriately and efficiently controlled, 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 the vertically adjacent coil members 11, 11 via a tubular communication member 18A. and the free end of the uppermost (upper) coil member 11 are connected to a water supply pipe 18B and a drain pipe 18C, respectively.

When the cooling circuit described above is employed, cooling water supplied from a water storage tank (not shown) flows into the inner space of the lower coil member 11 via the water supply pipe 18B, as indicated by the white arrow in FIG. It flows in and then flows through the internal space of the communicating member 18A and the internal space of the upper coil member 11 . The cooling water that has flowed through the internal space of the upper coil member 11 is discharged to the outside through a drain pipe 18C connected to the upper coil member 11 . Each coil member 11 is cooled by repeatedly circulating the cooling water as described above.

As shown in FIGS. 2 and 9 (a) and (b), 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). It is composed of the second coil member 21 . The second coil member 21 has a helical shape and includes a helical portion 22 functioning as the inner diameter side coil portion 6 and a first extension portion 23 and a second extension portion 24 extending from one end and the other end of the helical portion 22 . have.

Although not shown, the second coil unit 2B is provided with a cooling circuit for cooling the second coil member 21 while the induction heating device 1 is being energized. 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 . By providing such a cooling circuit, the temperature of the second coil member 21 can be appropriately and efficiently controlled, and the durability of the second coil member 21 can be improved.

The second coil unit 2B (second coil member 21) is detachably supported on the frame 30. As shown in FIG. In this embodiment, one end of a pair of horizontally extending support members 25, 25 [see FIGS. 9A and 9B] is fixed to the second coil member 21, and the other end of the support members The second coil unit 2</b>B is supported by the frame 30 by fixing it to the struts 32 of the frame 30 with nuts. In this case, the second coil unit 2B can be removed from the frame 30 by removing the nut fixing the other end of the support member 25 to the support 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 vertically movable along the central axis of both coil portions 5 and 6, and includes a lowered position at which the workpiece W to be heated is received and the heated workpiece W is delivered, and a workpiece W is reciprocatingly moved between the raised position where W is disposed between the outer diameter side coil portion 5 and the inner diameter side coil portion 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 first coil unit 2A having) the outer diameter side coil portion 5 via the power distribution member 8a, and the outlet side electrode 7b is electrically connected to the inner diameter side coil portion via the power distribution member 8b. 6 (second coil unit 2B having). In this embodiment, as shown in FIGS. 2 and 7, the power distribution member 8a is attached to the receiving portion 16 provided on the first extension portion 13 of the lower first coil member 11 constituting the first coil unit 2A. The power distribution member 8b is connected to the second extension 24 of the second coil member 21 as shown in FIGS. 2 and 9(a) and (b).

2 and 3, the first coil unit 2A having the outer coil portion 5 and the second coil unit 2B having the inner 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 on the second extension portion 14 of the upper first coil member 11 of the first coil unit 2A. 2 and 9(a) and (b), the other end of the power distribution member 8c is connected to (the first extension 23 of) the second coil member 21 constituting the second coil unit 2B. there is

Although detailed illustration is omitted, the power distribution members 8a to 8c can be configured by tubular bodies (rigid bodies) made of a conductive metal like the coil members 11 and 21 and the conduction member 15, and have flexibility. It can also be configured with an electric wire (cable wire). No matter what power distribution members 8a to 8c are used, the power distribution members 8a to 8c are detachably connected to connection objects (first coil member 11, second coil member 21, etc.).

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→power distribution member 8a→first coil unit 2A having outer coil portion 5→power distribution member 8c→second coil unit 2B (second coil member 21) having inner coil portion 6→power distribution member 8b→exit side A current 9 flows along the path from the electrode 7 b to the power source 4 . In the first coil unit 2A, the current 9 flows in the order of the first coil member 11 on the lower side→the conducting member 15→the first coil member 11 on the upper side.

Therefore, as shown in FIGS. 2 and 3, the annular outer ring electrically connected in series to the radially outer side and the radially inner side of the work W horizontally supported from below by the work support member 3, respectively. The diameter side coil portion 5 and the spiral inner diameter side coil portion 6 are arranged coaxially with the workpiece W, and in that state, the outer diameter side coil portion 5 is energized (high frequency power is supplied from the power supply 4 to the coil unit 2). ), substantially the same amount of current 9 flows through the outer diameter side coil portion 5 and the inner diameter side coil portion 6 . As a result, the outer diameter surface and the inner diameter surface of the work W are simultaneously induction-heated in the circumferential direction (entire area), and the heat of the outer diameter surface and the inner diameter surface that have been raised in temperature is transmitted toward the core part of the work W. As a result, the entire area is heated.

In short, if the work W is induction-heated using the induction heating apparatus 1 according to the present invention, it becomes possible to simultaneously heat the outer diameter side region and the inner diameter side region of the work W under substantially the same conditions. It becomes difficult for a difference to occur between the heating temperature (heating rate) of the outer diameter side region of the workpiece W and the heating temperature (heating 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 temperature of 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 rise rate at point A and the temperature rise rate at point B, and as shown in FIG. The point B could be efficiently heated compared to the case where the work W was induction-heated. Therefore, with the induction heating apparatus 1 according to the present invention, it is possible to efficiently and accurately induction-heat the entire short cylindrical workpiece W to a target temperature.

Further, in the induction heating device 1 according to the present invention, the first coil unit 2A having the outer diameter side coil portion 5 is attachable to and detachable from the frame 30 . Further, the first coil unit 2A has an annular portion 12 that constitutes the outer diameter side coil portion 5, and a plurality of first coil units supported by the frame 30 so as to be movable in the axial direction and detachable from the frame 30. 1 coil member 11 and a conductive member 15 that connects two vertically adjacent first coil members 11 so as to be conductive and that is attachable to and detachable from the first coil member 11 . Therefore, the specification of the outer diameter side coil portion 5 can be arbitrarily changed by changing the support positions and the number of the first coil members 11 supported by the frame 30 .

A specific example of 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. In this case, the distance between the coil members 11 is increased, the coil members 11 are fixed to the frame 30 (see FIG. 5), and the coil members 11 are electrically connected using the conductive member 15. good. At this time, as the conducting member 15, the connecting portion 15c whose length and the inclination angle with respect to the vertical direction are changed is used.

8 (a specification in which the axial dimension of the outer diameter side coil portion 5 is expanded without changing the coil pitch of the outer diameter side coil portion 5) from the specification shown in the upper portion of FIG. In the case of changing to . Also, from the specification shown in the upper part of FIG. 8 to the specification shown in the lower right part of FIG. When changing, the first coil member 11 supported by the frame 30 is removed, the first coil member 11 having the annular portion 12 with a large diameter is attached and fixed to the frame 30, and both coil members 11 are attached and fixed. can be electrically connected using the conducting member 15 .

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 changed arbitrarily. can.

From the above configuration, in the induction heating device 1 of the present embodiment, the specification of the outer diameter side coil portion 5 and/or the inner diameter side coil portion 6 can be easily changed. Therefore, even when the work W to be heated is changed, the specifications of the coil portions 5 and 6 can be easily changed to the optimum one for induction heating the work W after the change.

Therefore, the induction heating apparatus 1 according to the present invention can efficiently and accurately induction-heat the entire area of the short cylindrical work W to a target temperature, and furthermore, the outer diameter side coil portion 5 and the inner diameter side coil portion 5 for heating the work W can be heated by induction heating. It has the feature that the specification of the coil part 6 can be easily changed. Therefore, with the induction heating apparatus 1 according to the present invention, various short cylindrical workpieces W can be efficiently and accurately heated to a target temperature. is advantageous.

Although the induction heating device 1 according to one embodiment of the present invention has been described above, the induction heating device 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 was adopted, but the outer diameter side coil portion 5 is spiral and has a spiral shape. Alternatively, the inner diameter side coil portion 6 may be annular. In short, when the coil unit 2 is energized, 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 which are arranged coaxially with the both coil portions 5 and 6. Any device can be used as long as each part can be heated (induction heating) at the same time.

Further, the work W may be rotationally driven around its central axis during the induction heating of the work W. Although illustration is omitted, such a configuration can be realized by connecting the work support member 3 shown in FIG. . By doing so, it is advantageous in avoiding variations in the heating temperature at each part in the circumferential direction of the workpiece W, that is, in heating the entire workpiece W uniformly.

Further, 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

In the above description, the technical means of the present invention is applied to the heat treatment of (the base material of) the outer ring of the rolling bearing. It can also be preferably applied when heat-treating a retainer incorporated in a sliding 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 by no means limited to the above-described embodiments, and can be embodied in various forms without departing from the gist of the present invention. That is, the scope of the present invention is indicated by the claims, and includes equivalent meanings and all changes within the scope of the claims.

1 induction heating device 2 coil unit (heating part)
2A 1st coil unit 2B 2nd coil unit 4 power supply 5 outer diameter side coil portion 6 inner diameter side coil portion 7 electrode members 8a, 8b, 8c power distribution member 9 current 11 first coil member 12 annular portion 15 conduction member 17 bolt member 21 Second coil member 22 Spiral portion 30 Frame 32 Strut 33 Support component W Work (short cylindrical work)

Claims (5)

An induction heating device comprising a heating unit for heating a short cylindrical workpiece to a target temperature and a power supply for supplying high-frequency power to the heating unit,
The heating unit includes a first coil unit arranged coaxially with the work radially outwardly of the work and having an outer diameter side coil part capable of simultaneously heating each circumferential portion of the outer diameter surface of the work; a second coil unit having an inner diameter side coil portion arranged coaxially with the work on the radially inner side of the work and capable of simultaneously heating each circumferential portion of the inner diameter surface of the work; the first coil unit and the second coil unit and a frame that detachably supports the
The outer diameter side coil portion and the inner diameter side coil portion are electrically connected in series,
The first coil unit includes a first coil member having a portion forming the outer diameter side coil portion, and the second coil unit includes a second coil member having a portion forming the inner diameter side coil portion. prepared,
A member for supplying an electric current to a portion constituting an outer diameter side coil portion of the first coil member is connected to a longitudinal middle portion of the first coil member made of a tubular body made of a conductive metal. , a member for supplying or discharging cooling water flowing through the internal space of the first coil member is connected to both ends of the first coil member in the longitudinal direction,
A member for supplying an electric current to a portion constituting an inner diameter side coil portion of the second coil member is connected to a middle portion in the longitudinal direction of the second coil member made of a tubular body made of a conductive metal, and An induction heating device , wherein a member for supplying or discharging cooling water flowing through an internal space of the second coil member is connected to both longitudinal ends of the second coil member . The first coil member has an annular portion as a portion constituting the outer diameter side coil portion, and is supported by the frame in a state that it can move in the axial direction and is detachable from the frame,
The first coil unit is a member for supplying current to a portion forming an outer diameter side coil portion of the first coil member, and electrically connects two adjacent first coil members, 2. The induction heating device according to claim 1, further comprising a conducting member that can be attached to and detached from the one coil member. 3. The induction heating device according to claim 2, wherein said 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 member has a spiral portion as a 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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