JP2017183097A - Heat treatment apparatus and heat treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment apparatus capable of uniform induction heating of a work, while setting an optimum coil pitch easily and accurately according to the work.SOLUTION: A heating section 2 for induction heating a work W to a target temperature includes multiple coil members 11 each having a ring-shaped coil 11a arranged coaxially with the work W, a frame 21 for supporting each coil member 11 movably in the axial direction, while maintaining the coaxiality of the coils 11a, and a regulation member 23 for regulating relative approaching and receding movements of two adjoining coil members 11.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a heat treatment apparatus and a heat treatment method, and more particularly to a heat treatment apparatus and a heat treatment method in which a process of induction heating a workpiece to a target temperature is performed.

  As is well known, in the manufacturing process of a metal member that requires high mechanical strength, such as a bearing ring of a rolling bearing, a heat treatment (firing) for imparting the mechanical strength required for the metal member. (Hardening treatment) is performed. This heat treatment includes a heating step for heating the workpiece to be heat-treated to a target temperature, a cooling step for cooling the heated workpiece, and the like. The heating step can be carried out using, for example, an atmosphere heating furnace such as a mesh belt type continuous furnace. However, since the atmosphere heating furnace needs to be heated together with the atmosphere, the heat treatment apparatus has low energy efficiency. There is a problem that it becomes a big deal.

  Therefore, as described in Patent Document 1 below, in the heating process, the workpiece may be heated by high-frequency induction heating. If induction heating is used, the workpiece can be directly heated, so that high energy efficiency can be achieved, and a compact heat treatment apparatus can be realized. Further, when the workpiece to be heat-treated is a ring-shaped member such as a bearing ring of a rolling bearing, as described in Patent Document 1, a plurality of workpieces held coaxially are A so-called continuous heating method in which a plurality of ring-shaped members are sequentially heated by relative movement in the axial direction with respect to the energized heating coil arranged coaxially can be employed. Such a continuous heating method has an advantage that each of a plurality of workpieces can be efficiently induction-heated to a target temperature.

Japanese Patent Laying-Open No. 2015-67881

  By the way, in the case where a load is applied to the entire member (members in the circumferential direction of the member) as in the above-described raceway ring, if there is a difference in the strength of each member in the circumferential direction, a portion having low strength is likely to become a starting point of breakage. Such a problem may occur, for example, when the temperature of the workpiece after completion of heating varies in the circumferential direction. Therefore, the inventors of the present application hold the workpiece at a constant temperature for a predetermined time (hold the workpiece soaked) at the final stage (second half) of the heating process in which the continuous heating method is performed, thereby An attempt was made to equalize the temperature of each part in the circumferential direction.

  Here, as the heating coil for induction heating, a coil material made of a conductive metal and spirally wound (hereinafter referred to as “spiral coil”) is usually used. In general, the helical coil has a characteristic that the output becomes stronger as the coil pitch (interval between adjacent coils in the axial direction at an arbitrary circumferential position) becomes denser, and the output becomes weaker as the coil pitch becomes sparse. Therefore, the inventors of the present application, when performing the heat treatment in the above-described aspect, the helical coil 100 whose coil pitch is adjusted in the aspect shown in FIG. 15, more specifically, the coil pitch on the heating start side is relatively dense. An attempt was made to use the helical coil 100 that was set and the coil pitch on the heating end side was set relatively sparse. In this case, as the workpiece 101 moves relative to the spiral coil 100 in the axial direction, the workpiece 101 is first positively heated to a predetermined temperature and then kept soaked.

  However, even when the spiral coil 100 with the coil pitch adjusted in the above-described mode is used, the temperature of each part in the circumferential direction of the workpiece 101 after heating is nonuniform. The reason is that in the helical coil 100, the coil pitch is non-uniform in each circumferential portion of the workpiece 101 (the coil pitch gradually changes in the circumferential direction of the workpiece 101), and the coil pitch is changed by changing the coil pitch. It is inferred that the shape of 100 changes in an undesired manner.

  Further, in the case where the workpiece 101 is induction-heated in the mode shown in FIG. 15, for example, when the workpiece 101 to be heat-treated is changed to one having a different axial dimension, the coil pitch of the spiral coil 100 is changed (adjusted). It is necessary to take such measures. However, since it takes a lot of time and effort to accurately adjust the coil pitch of the helical coil 100, there is a problem that heat treatment cannot be efficiently performed on the workpiece.

  In view of the above circumstances, the object of the present invention is to allow induction heating of a workpiece to a target temperature without causing the temperature of the workpiece to be heat-treated to vary in each part in the circumferential direction. An object of the present invention is to provide technical means capable of easily and accurately setting a simple coil pitch (heating condition).

  The present invention, which was created to achieve the above-mentioned object, has a heating unit that induction-heats a workpiece to a target temperature and a plurality of coaxially held workpieces relative to the energized heating unit in the axial direction. In the heat treatment apparatus including the moving mechanism, the heating unit includes a coil unit disposed coaxially with the workpiece so as to surround the workpiece, and the portions in the extending direction of the coil unit are located on the same plane. With respect to one and the other of two coil members adjacent to each other in the axial direction and a frame body that supports each of the plurality of coil members and the plurality of coil members so as to be axially movable while maintaining the coaxiality of the coil portions. And a restricting member that removably attaches and restricts relative approach and separation of two coil members adjacent in the axial direction.

  If it is the heat processing apparatus which has the said structure, since the several coil member which each has a coil part is supported so that an axial direction movement is possible with respect to a frame, coil pitch is the position of the coil member with respect to a frame, It can be adjusted and set by adjusting and managing the posture. Therefore, even if the coil pitch is adjusted, the posture of each coil member (coil portion) can be maintained in an appropriate state (a posture parallel to the workpiece to be heat treated), and the coil of the spiral coil 100 shown in FIG. As in the case of adjusting the pitch, the coil pitch does not gradually change in the circumferential direction of the workpiece and the coil shape does not change. Therefore, by adjusting the coil pitch, if a temperature rising zone in which the coil pitch is set relatively dense and a soaking zone in which the coil pitch is set relatively sparse are provided, heat treatment can be performed. Even when the target workpiece is a ring-shaped workpiece such as a bearing ring of a rolling bearing, each workpiece can be appropriately induction-heated to the target temperature without causing the workpiece temperature to vary in the circumferential direction.

  Moreover, according to said structure, the separation distance (coil pitch) of the axial direction of two coil members adjacent in an axial direction can be adjusted and set based on the axial direction dimension of a control member. Therefore, when adjusting and setting the coil pitch, if a regulating member having a predetermined axial dimension is attached and fixed to one and the other of two adjacent coil members in which at least one is axially movable. The coil pitch can be adjusted and set easily and accurately to the optimum coil pitch according to the workpiece.

  The coil member may be provided with a first protrusion and a second protrusion that engage with the restricting member in the axial direction and the extending direction thereof. In this way, a desired coil pitch can be realized easily and accurately (coil pitch reproducibility is improved).

  Two coil members adjacent in the axial direction can be electrically connected via a restricting member. In this way, since a plurality of coil members can be handled electrically as one multi-turn coil, the power feeding circuit can be made simple.

  The coil member can be formed in an end shape with a tubular body made of a conductive metal. In this case, if the heating unit further includes a communication member that communicates the internal spaces of the two coil members adjacent in the axial direction, a series of fluid passages can be formed by the coil member and the communication member. . This fluid passage can be utilized as a part of a cooling circuit for circulating cooling water, for example. If such a cooling circuit is provided, temperature control of the heating unit can be performed appropriately and efficiently. Further, if the communication member is formed of a flexible material, the communication member can be deformed in such a manner as to follow this even when the coil pitch is changed. Therefore, even when the above cooling circuit is necessary, it is possible to reduce the trouble of reconfiguring the cooling circuit every time the coil pitch is changed.

  Each coil member is preferably detachable from the frame. In this way, it is possible to easily cope with an increase / decrease in the number of coil members installed, replacement of coil members, and the like.

  In order to achieve the above object, in the present invention, the plurality of workpieces held coaxially are moved relative to each other in the axial direction with respect to the energized heating section, so that the plurality of workpieces are sequentially brought to the target temperature. A heat treatment method including a heating step of induction heating, wherein the heating step has a coil portion arranged coaxially with the workpiece so as to surround the workpiece, and each portion in the extending direction of the coil portion is on the same plane A plurality of coil members positioned in the frame, a frame holding each of the plurality of coil members so as to be axially movable while maintaining the coaxiality of the coil portions, and one of the two coil members adjacent in the axial direction and Heating is performed by a heating unit that is detachably attached to each of the other, and that includes a regulating member that regulates relative approach and separation of adjacent coil members in the axial direction. To provide a processing method.

  With such a heat treatment method, it is possible to receive the same effects as when the heat treatment apparatus according to the present invention is employed.

  As described above, according to the present invention, the workpiece can be induction-heated to the target temperature without causing the temperature of the workpiece to be heat-treated to vary at each portion in the circumferential direction, and the optimum coil pitch according to the workpiece can be obtained. (Heating conditions) can be set easily and accurately.

It is a figure which shows notionally the whole structure of the heat processing apparatus which concerns on embodiment of this invention. It is a flowchart of the process implemented with the heat processing apparatus shown in FIG. It is a top view (top view) of the heating part which comprises the heat processing apparatus shown in FIG. FIG. 5 is a cross-sectional view taken along line C-D-E-F in FIG. 3. FIG. 5 is a cross-sectional view taken along line GG in FIG. 4. It is a top view of the one coil member which comprises the heating part shown in FIG. It is a top view of the other coil member which comprises the heating part shown in FIG. FIG. 6 is a partially enlarged perspective view of FIG. 5. It is a figure for demonstrating the change aspect of the coil pitch in the heating part shown in FIG. It is a schematic diagram for demonstrating the flow of the cooling water in a heating part. It is a longitudinal cross-sectional view of the workpiece | work used by the confirmation test. It is a figure which shows the temperature change of the workpiece | work at the time of carrying out induction heating of the workpiece | work shown in FIG. 11 with the heat processing apparatus conceptually shown in FIG. It is a figure which shows the temperature change of the workpiece | work when the workpiece | work shown in FIG. 11 is induction-heated with the heat processing apparatus shown in FIG. It is a figure which shows the test result implemented in order to confirm the reproducibility of a coil pitch. It is a schematic front view of the heating part in the heat processing apparatus used in the examination process of this invention.

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

  FIG. 1 is a diagram conceptually showing the overall structure of a heat treatment apparatus 1 according to an embodiment of the present invention. The heat treatment apparatus 1 shown in FIG. 1 is a steel workpiece W, more specifically, for example, a steel material having a carbon content of less than 0.8% by mass (S45C classified as carbon steel for mechanical structure defined in JIS G4051 S53C or the like) is used for subjecting a ring-shaped workpiece W (for example, an outer ring of a rolling bearing) to a quench hardening treatment as a heat treatment. As shown in FIG. The transport process S2 and the cooling process S3 are sequentially performed.

  As shown in FIG. 1, the heat treatment apparatus 1 mainly includes a heating unit 2, a holding unit 3, and a high frequency power source 4 used in the heating step S <b> 1, a transfer device 5 used in the transfer step S <b> 2, and a cooling step S <b> 3. And a cooling unit 6 used in the above. The cooling unit 6 includes a cooling liquid tank 61 in which a cooling liquid (for example, quenching oil) 62 held at an appropriate temperature is stored, and the transport device 5 includes, for example, a belt conveyor.

  The holding unit 3 holds a plurality of workpieces W to be heat-processed coaxially, and in this embodiment, holds the plurality of workpieces W coaxially in a stacked state. Therefore, in the present embodiment, the “axial direction” referred to in the present invention is the vertical direction (vertical direction). In the present embodiment, the plurality of workpieces W held by the holding unit 3 receive the output of a drive mechanism (not shown) and are sent upward, so that the workpieces W are sequentially introduced into the inner periphery of the heating unit 2. .

  Hereinafter, the heating unit 2 having the characteristic configuration of the present invention will be described in detail with reference to FIGS.

  As shown in FIGS. 3 to 5, the heating unit 2 includes a plurality of (10 in the illustrated example) coil members 11 arranged in multiple stages along the vertical direction, and a frame that supports the coil members 11 so as to be movable up and down. A body 21 and a relay component 7 for energizing the coil member 11 by bringing the electrode provided on the coil member 11 and the electrode of the high-frequency power source 4 (see FIG. 1) into contact with each other are provided.

  As shown in FIG. 3, each coil member 11 is arranged coaxially with the workpiece W held by the holding portion 3 (see FIG. 1), and is formed in a ring shape that is endless in the circumferential direction so as to be able to surround the workpiece W. A coil portion 11a. Moreover, each coil member 11 has the 1st and 2nd extension parts 11b and 11c extended from the circumferential direction one end part and other end part of the coil part 11a. In this embodiment, between the uppermost coil member 11 and the lowermost coil member 11, two types of coil members 11 having different shapes of the extension portions 11b and 11c are alternately arranged. As shown in FIG. 6, one of the two types of coil members 11 has extension portions 11b and 11c whose free ends are relatively spaced from the coil portion 11a, and the two types of coil members. As shown in FIG. 7, the other of 11 has the extension parts 11b and 11c arrange | positioned in the position where the free end relatively approached the coil part 11a. This is for avoiding interference between the extension portions 11b and 11c of the two coil members 11 adjacent in the vertical direction.

  Each coil member 11 is formed in an end shape by bending a tubular body (for example, a copper tube) made of a conductive metal, and at least the coil portion 11a has the same plane in the extending direction (circumferential direction). Above, here it lies on a horizontal plane. As shown in FIGS. 3 to 5, each coil member 11 has the center axis of the coil portion 11 a coincided with the center axis of the coil portion 11 a of the other coil member 11 and the circumferential end portion of the coil portion 11 a. Is matched with the phase of the circumferential end of the coil portion 11a of the other coil member 11 in a horizontal posture on the frame body 21.

  A receiving member 12 made of a conductive metal is welded to each coil member 11, and one end or the other end of a regulating member 23 described later is attached and fixed (bolted) to the receiving member 12. In the uppermost coil member 11, the receiving member 12 is welded only to the first extension portion 11b, and in the lowermost coil member 11, the receiving member 12 is welded only to the second extension portion 11c. Each of the eight coil members 11 arranged between the coil member 11 and the lowermost coil member 11 has a receiving member 12 welded to both the first and second extension portions 11b and 11c. .

  As shown in FIG. 3 to FIG. 5, the frame body 21 includes a pedestal 21 a disposed on the lower side of the lowermost coil member 11 and a plurality of frames (three in this embodiment) erected on the pedestal 21 a. The coil members 11 are supported by the frame body 21 via support parts 22 provided at three locations spaced in the circumferential direction of the coil portion 11a. Each support column 21b is provided with a guide portion 21c for guiding the up-and-down movement of the coil member 11, and the guide portion 21c is formed by a long hole-like through hole extending in the vertical direction. Both the base 21a and the column 21b are made of an insulating material.

  Each support component 22 is fastened to a nut 11d whose inner end in the radial direction is fixed to the outer periphery of the coil member 11, and the vicinity of the outer end in the radial direction is inserted into the guide portion 21c of the corresponding column 21b. The bolt member 22a includes first and second nuts 22b and 22c that are disposed on the radially inner side and the outer side of the support column 21b and screwed to the bolt member 22a so as to be relatively close to and away from each other.

  With the above-described configuration, each coil member 11 has a predetermined position in the vertical direction when the nuts 22b and 22c are moved relatively close to each other to support the pillars 21b in each of the support parts 22 provided at three locations in the circumferential direction. It is supported in a fixed manner. On the other hand, when the nuts 22b and 22c are relatively moved away from each other in each support component 22 to release the clamping force of the support column 21b, the coil member 11 can be moved up and down. It is possible to adjust the arrangement position and posture in the vertical direction. Furthermore, from the above configuration, the coil member 11 can be removed from the frame body 21 by removing the bolt member 22a from the nut 11d in all the support components 22 provided in each coil member 11. Therefore, each coil member 11 can be moved up and down with respect to the frame body 21 and is detachable.

  As shown in FIGS. 3 to 5, the heating unit 2 includes (a plurality of) regulating members 23 that regulate the relative approach and separation of the two coil members 11 that are adjacent in the vertical direction. In the following description, when the two coil members 11 that are adjacent to each other are described, the coil member 11 that is disposed on the upper side is referred to as “coil member 11A” and is disposed on the lower side for convenience. The coil member 11 to be used is also referred to as “coil member 11B”. However, in each figure which shows embodiment of this invention, the code | symbol 11A, 11B is not shown.

  Each restricting member 23 is formed of a conductive metal material, and has a first head 24 bolted to the coil member 11A (the receiving member 12 welded to the first extension portion 11b). The second head 25 bolted to the coil member 11B (the receiving member 12 welded to the second extension portion 11c thereof), and a predetermined angle with respect to the vertical direction between the heads 24, 25 And a connecting portion 26 interposed therebetween. As described above, since the regulating member 23 made of a conductive metal is bolted to the coil member 11, the coil members 11A and 11B are electrically connected to each other via the regulating member 23, the receiving member 12, and the bolt. Connected to. Therefore, in this embodiment, among the plurality of coil members 11 arranged in multiple stages, the uppermost and lowermost coil members 11 are electrically connected to the high-frequency power supply 4 (FIG. 1) via the relay component 7. Yes.

  As shown in an enlarged view in FIG. 8, the receiving member 12 welded to the first extension portion 11b of each coil member 11 is associated with the upper end surface 24a and the peripheral end surface 24b of the first head 24 of the regulating member 23, respectively. First and second projections 13 and 14 that can be combined are provided, and the receiving member 12 welded to the second extension portion 11c of each coil member 11 has a lower end surface 25a of the second head 25 of the restricting member 23 and First and second protrusions 13 and 14 that can engage with the peripheral end face 25b are provided. In short, each coil member 11 is provided with a first protrusion 13 that engages with the restriction member 23 in the axial direction and a second protrusion 14 that engages with the restriction member 23 in the extending direction (circumferential direction). Yes.

  In this embodiment, two types of restricting members 23 having different axial dimensions are used. More specifically, as shown in FIG. 4-5, in the sixth to sixth coil members 11 from the bottom to the bottom, the restricting member 23 having a relatively small axial dimension is in comparison with the coil members 11A and 11B. In the sixth to uppermost coil member 11 from the bottom, a restricting member 23 having a relatively large axial dimension is attached to the coil members 11A and 11B. With such a configuration, in the lower region of the heating unit 2, that is, on the start side of the heating step S2, the coil pitch is relatively dense, and the temperature raising zone in which the workpiece W can be actively heated to a predetermined temperature. Z1 is formed, and in the upper region of the heating unit 2, that is, the end of the heating step S2, the coil pitch is relatively sparse and the soaking temperature holding zone Z2 capable of keeping the workpiece W soaked is formed. The

  The heating unit 2 can be provided with a cooling circuit for cooling the coil member 11. If such a cooling circuit is provided, temperature control of the coil member 11 can be performed appropriately and efficiently. The cooling circuit of the present embodiment is a single system, and as shown in FIGS. 3 and 4, the water supply pipe 28a is connected to the free end of the first extension portion 11b of the lowermost coil member 11, and the uppermost coil. The drain pipe 28b is connected to the free end of the second extension portion 11c of the member 11, and the internal spaces of the coil members 11A and 11B adjacent in the vertical direction are connected via the communication member 29. The communication member 29 is formed of a tubular body formed of a flexible material, here, a rubber material, and one end and the other end thereof are connected to the free ends of the coil members 11A and 11B, respectively. If the communication member 29 is formed of a flexible material, the coil pitch can be adjusted without eliminating the connection state between the communication member 29 and the coil members 11A and 11B. In addition, in order to avoid complication of drawing, the communication member 29 is shown only in FIG.

  Here, the flow of the cooling water in the heating unit 2 of the present embodiment will be briefly described with reference to FIG. Cooling water supplied from a water storage tank (not shown) flows into the inner space of the lowermost coil member 11 through the water supply pipe 28a as shown by the white arrow in FIG. 10 is omitted) and the internal space of the coil member 11 is alternately circulated and directed upward. And the cooling water which distribute | circulated the internal space of the uppermost coil member 11 is discharged | emitted outside through the water distribution pipe 28b connected to the free end of the 2nd extension part 11c of the uppermost coil member 11 (FIG. (See also 3).

  Hereinafter, the embodiment of the hardening hardening process of the workpiece | work W using the heat processing apparatus 1 which has the above structure is demonstrated.

  As shown in FIG. 2, the quench hardening process includes a heating step S1 for induction heating the workpiece W to a target temperature, a transport step S2 for transporting the workpiece W heated to the target temperature to the cooling unit 6, and a workpiece And a cooling step S3 for cooling and quenching W.

(A) Heating step S1
In the heating step S1, the plurality of workpieces W held coaxially by the holding unit 3 (see FIG. 1) are sequentially heated to the target temperature. Specifically, first, a plurality of workpieces W are stacked on the holding unit 3 so that the respective central axes coincide with each other. When the workpiece W is, for example, an outer ring of a rolling bearing, the workpiece W has a smaller axial dimension than a radial dimension. Therefore, stacking the workpieces W has an advantage that the posture of the workpieces W during the heating step S1 is stabilized. Although detailed illustration is omitted, the work of stacking the workpieces W can be automatically performed.

  When an upward feed force is applied from a driving mechanism (not shown) to the plurality of workpieces W held coaxially in a stacked state, the workpiece W is heated in an energized state through the lower end opening of the heating unit 2. It is introduced into the inner periphery of the part 2 (coil part 11a). Then, by continuously operating the drive mechanism, the workpiece W is sent upward and finally discharged to the outside of the heating unit 2 through the upper end opening of the heating unit 2. Since the temperature rising zone Z1 and the soaking zone Z2 are provided in the lower region and the upper region of the heating unit 2, respectively, the workpiece W introduced into the inner periphery of the heating unit 2 is lifted. Induction heating is performed to a predetermined temperature while passing through the temperature zone Z1, and thereafter, the temperature is maintained at a constant temperature while passing through the soaking zone Z2. As a result, the workpiece W is induction-heated to a target temperature, and the entire workpiece W can be heated to a substantially uniform temperature without causing the temperature of the workpiece W to vary at each portion in the circumferential direction.

(B) Conveyance process S2
In this conveyance process S2, the workpiece | work W heated to target temperature is sequentially conveyed by the conveying apparatus 5 to the cooling part 6 (cooling liquid tank 61) (refer FIG. 1).

(C) Cooling step S3
In this cooling step S3, the workpiece W transferred to the cooling liquid tank 61 by the transfer device 5 is cooled to a predetermined temperature range by being immersed in the cooling liquid 62 stored in the cooling liquid tank 61, It is quenched and hardened (see FIG. 1).

  By the above procedure, the quench hardening processing of the workpiece W using the heat treatment apparatus 1 is completed. The workpiece W that has been subjected to the quench hardening process is then subjected to predetermined processes such as a tempering process and various finishing processes. Thereby, the work W becomes a finished product.

  According to the heat treatment apparatus 1 according to the present invention described above, since each of the coil members 11 having the coil portions 11a is supported so as to be movable up and down with respect to the frame body 21, the coil pitch is relative to the frame body 21. It can be adjusted and set by adjusting and managing the position and orientation of each coil member 11. Therefore, even when the coil pitch is adjusted, the posture of each coil member 11 (coil portion 11a) can be maintained in an appropriate state, that is, in a posture parallel to the workpiece W to be heat-treated, in addition to the spiral shown in FIG. As in the case of adjusting the coil pitch of the coil 100, the coil pitch does not gradually change in the circumferential direction of the workpiece W, and the shape of the coil portion 11a does not change. Therefore, by adjusting the coil pitch, the temperature rising zone Z1 is provided in the lower region of the heating unit 2, and the temperature equalizing holding zone Z2 for holding the workpiece W in the upper region of the heating unit 2 is provided. Then, as the workpiece W passes through the opposing regions of the coil portions 11a, the workpiece W is appropriately induction-heated to the target temperature without causing the temperature of the workpiece W to vary in the circumferential direction. be able to.

  Moreover, according to the heat processing apparatus 1 which concerns on this invention, a coil pitch can be set based on the axial direction (vertical direction) dimension of the control member 23. FIG. Therefore, for example, even when the workpiece W to be heat-treated is changed to one having a different axial dimension (this is referred to as “work W ′”), at least one of the workpieces can be moved up and down after the regulating member 23 is removed. If the other regulating member 23 (the regulating member 23 having a different axial dimension from the regulating member 23 removed from the coil member 11) is bolted to one and the other of the two adjacent coil members 11, the coil It is possible to easily and accurately set the pitch to the optimum coil pitch according to the work W ′, that is, the heating unit 2 can be easily changed to a form in which the work W ′ can be appropriately induction-heated (as described above. (See FIG. 9). In particular, in the present embodiment, each coil member 11 (the receiving member 12 welded to the coil member 11) is provided with the first and second protrusions 13 and 14 that respectively engage with the regulating member 23 in the axial direction and the circumferential direction thereof. In addition to further facilitating the adjustment / setting operation of the coil pitch, the relative movement of the two adjacent coil members 11 can be reliably regulated after the adjustment of the coil pitch.

  In short, if the configuration of the present invention is adopted, the coil pitch can be adjusted and set easily and accurately according to the size of the workpiece W, the temperature history of the workpiece to be acquired when passing through the heating unit 2, and the like. it can. Therefore, the heating unit 2 has a temperature rising zone Z1 and a soaking / holding zone Z2 from the form in which the heating zone Z1 and the soaking / holding zone Z2 are provided one by one as in the embodiment described above. Are alternately provided (two first heating zones, first soaking zone, second heating zone, and second soaking zone). It can also be done easily and accurately.

  As mentioned above, although an example of embodiment of this invention was demonstrated, embodiment of this invention is not limited to this.

  For example, in the above embodiment, only one system of cooling circuit is provided in the heating unit 2, but two or more cooling circuits may be provided. In particular, when there is a concern that the required coil cooling capacity is insufficient with only one system of cooling circuit, such as when a large number of coil members 11 are used, it is effective to provide a plurality of cooling circuits. is there. In this way, even when a plurality of cooling circuits are provided, a plurality of cooling circuits can be easily constructed because the heating unit 2 is provided with a plurality of coil members 11 separated from each other.

  Further, the configurations of the support component 22 and the regulating member 23 used in the above embodiment are merely examples, and can be appropriately changed as long as they can perform the same function. In the above embodiment, the receiving member 12 is welded to the coil member 11, and the regulating member 23 is bolted to the receiving member 12. However, the regulating member 23 is bolted directly to the coil member 11. It doesn't matter.

  In the above embodiment, the plurality of workpieces W are sequentially heated to the target temperature by induction heating, and the workpiece W heated to the target temperature by induction is sequentially sent to the conveying step S2 and further to the cooling step S3. The transport process S2 and the cooling process S3 may be performed collectively on the plurality of workpieces W that have been heated.

  Further, in the above-described embodiment, the relative movement direction of the plurality of workpieces W held coaxially by the heating unit 2 and the holding unit 3 is the vertical direction, but the present invention is configured to relatively move both in the horizontal direction. The present invention can also be applied to the heat treatment apparatus 1 configured as described above.

  In addition to the outer ring of the rolling bearing, the heat treatment apparatus 1 according to the present invention includes, for example, an inner ring of a rolling bearing, a sliding bearing, an outer joint member constituting a constant velocity universal joint, an inner joint member, a rolling bearing, and a constant velocity universal. This can be preferably applied when heat-treating a steel ring-shaped member such as a cage incorporated in a joint.

  In addition, the heat treatment apparatus 1 according to the present invention can be preferably applied not only to a ring-shaped workpiece W but also to a heat treatment for a disk-shaped or columnar workpiece.

  In order to demonstrate the usefulness of the present invention, (1) when the workpiece is induction-heated by a heat treatment apparatus using the helical coil 100 shown in FIG. 15 as the heating unit, and (2) the present invention shown in FIG. In each of the cases where the workpiece is induction-heated with the heat treatment apparatus to which the above is applied, whether or not there is a difference in the temperature history (temperature increase mode) of the workpiece when the workpiece is heated to about 900 ° C. was confirmed. In any of the above (1) and (2), by adjusting the coil pitch, a heating zone for positively heating the workpiece is provided in the first half of the heating section, and the workpiece is placed in the second half of the heating section. A soaking zone that can keep soaking is provided.

  As shown in FIG. 11, the workpiece used in this confirmation test is a rolling bearing (conical roller bearing) formed with a small-diameter inner diameter d1: 146 mm, an outer diameter d2: 170 mm, and an axial dimension d3: 29 mm. It is an outer ring. Moreover, in this confirmation test, as shown in FIG. 11, the temperature of the two points (A part and B part) which made the phase different 180 degree | times in the circumferential direction among the said works was measured.

  The workpiece temperature measurement result in the case (1) is shown in FIG. 12, and the workpiece temperature measurement result in the case (2) is shown in FIG. As is apparent from FIG. 12, when the helical coil 100 is used for induction heating of the workpiece, the temperature of the workpiece becomes non-uniform in each part in the circumferential direction. On the other hand, when the product of the present invention is used for induction heating of the workpiece, the temperature of the workpiece is substantially uniform in each part in the circumferential direction as shown in FIG. Refer to “temperature of part A (after pitch adjustment)” and “temperature of part B (after pitch adjustment)” respectively shown].

  In order to confirm the influence of the coil pitch of the induction heating coil on the temperature rise mode of the workpiece, the workpiece was heated with a constant coil pitch in a heat treatment apparatus to which the present invention was applied to the heating section. The temperature measurement result in the A part of the workpiece in this case is also shown in FIG. 13 [see “temperature of A part (before pitch adjustment)” indicated by a one-dot chain line in FIG. 13]. As can be seen from FIG. 13, in this case, the temperature of the work continues to rise, so that it is substantially impossible to keep the work soaked.

  Furthermore, the heat treatment apparatus according to the present invention can easily and accurately realize a predetermined coil pitch, that is, increase the reproducibility of the coil pitch, because the heating unit has the above-described regulating member. In order to demonstrate that such an effect can be obtained, when the workpiece is induction-heated in the first state set to a predetermined coil pitch, the first state is changed to a second state in which the coil pitch is different. The temperature history of the workpiece was observed in both cases where the pitch was returned to the first state and the workpiece was induction-heated. The result is shown in FIG. In FIG. 14, the temperature history of the workpiece when the workpiece is induction-heated in the first state of the first time is shown by a solid line, and the temperature history of the workpiece when the workpiece is induction-heated in the second time of the first state is shown. It is indicated by a dotted line (broken line). As is clear from the results shown in the figure, the heat treatment apparatus according to the present invention has extremely high reproducibility of the coil pitch, and therefore can heat the work to be heat-treated with high accuracy with a desired temperature history.

  From the above test results, the usefulness of the present invention was demonstrated.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 2 Heating part 3 Holding part 11 Coil member 11a Coil part 13 1st protrusion 14 2nd protrusion 21 Frame 23 Restriction member 29 Communication member S1 Heating process S3 Cooling process W Work Z1 Temperature rising zone Z2 Soaking | uniform-heating holding zone

Claims (9)

In a heat treatment apparatus comprising: a heating unit that induction-heats a workpiece to a target temperature; and a drive mechanism that moves a plurality of coaxially held workpieces relative to the energized heating unit in an axial direction.
The heating unit includes a coil unit arranged coaxially with the workpiece so as to surround the workpiece, and a plurality of coil members in which each part in the extending direction of the coil unit is located on the same plane; Each of the coil members is removably attached to one and the other of the two coil members adjacent to each other in the axial direction and a frame body that is supported so as to be axially movable while maintaining the coaxiality of the coil portions. And a restricting member for restricting relative approach and separation of two coil members adjacent in the axial direction.   The heat treatment apparatus according to claim 1, wherein the coil member has a first protrusion and a second protrusion that engage with the restriction member in an axial direction and an extending direction thereof, respectively.   The heat treatment apparatus according to claim 1 or 2, wherein two coil members adjacent in the axial direction are electrically connected via the restricting member.   The heat processing apparatus as described in any one of Claims 1-3 in which the said coil member is formed in the end shape with the tubular body which consists of an electroconductive metal.   The heat treatment apparatus according to claim 4, wherein the heating unit further includes a communication member that communicates the internal spaces of the two coil members adjacent in the axial direction, and the communication member is formed of a flexible material.   The heat treatment apparatus according to any one of claims 1 to 5, wherein the coil member is detachable from the frame.   The heat treatment apparatus according to any one of claims 1 to 6, wherein the workpiece is a bearing ring of a rolling bearing. A heat treatment method including a heating step of inductively heating the plurality of workpieces sequentially to a target temperature by relatively moving the plurality of workpieces held coaxially in an axial direction with respect to the energized heating unit,
In the heating step, the workpiece has a coil portion arranged coaxially with the workpiece so as to surround the workpiece, and a plurality of coil members in which each portion in the extending direction of the coil portion is located on the same plane; A frame that supports each of the plurality of coil members so as to be axially movable while maintaining the coaxiality of the coil portions, and one of the two coil members that are adjacent in the axial direction at one end and the other. A heating member provided with a regulating member that is detachably attached to each of the other and regulates the relative approaching and separating movement of the two coil members adjacent in the axial direction. Heat treatment method. The heat treatment method according to claim 8, wherein the workpiece is a bearing ring of a rolling bearing.

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