JP2002080911A - Method for eliminating strain and work hardening of blank for clutch rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly and economically eliminate any strain and work hardening generated in an inner circumferential edge of a concentric blank for manufacturing a clutch rotor without losing any required strength. SOLUTION: The blank 1 for the clutch rotor is alternately transferred immediately below and above six induction coils 5, 5, etc., successively by a feeding mechanism 6, and the high frequency magnetic field of 25 kHz is applied to the circumferential edge 3 of a center hole 2 from an upper surface side or a lower surface side thereof alternately by three seconds. The upper surface side or the lower surface side is alternately head-generated by the eddy current loss attributable thereto, and the temperature of the circumferential edge 3 of the center hole 2 finally rises to 700-730 deg.C. Then, the heat-treated blank 1 for the clutch rotor is placed in a heat insulation box, and left therein for about four hours and slowly cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch for forging and forming an inner cylindrical portion and an outer cylindrical portion on a blank for a clutch / rotor, that is, a concentric blank obtained by performing concentric outer punching and punching. -Stress distortion occurring in the inner peripheral edge of the concentric blank in the press working step prior to the rotor forging forming step, particularly in order to prevent cracks that may occur in the inner cylindrical portion formed in the step. The present invention also relates to a method for eliminating stress strain and work hardening of a clutch / rotor blank for eliminating work hardening.

[0002]

2. Description of the Related Art A clutch / rotor blank, that is, a concentric blank having a central hole as shown in FIG.
As shown in FIG. 4B, the inner cylindrical portion is first forged, and then, as shown in FIG. 4C, the outer cylindrical portion is forged. Further, as shown in FIG. 4 (a), the blank for the clutch / rotor is formed from a sheet material of a predetermined metal material into a concentric blank having a central hole in a concentric manner by punching and drilling an outer shape by a press machine. is there.

In the process of forming such a clutch / rotor blank into a concentric blank from the above-described metal material plate in a pressing step of punching and drilling, the outer peripheral edge and the inner peripheral edge of the blank are subjected to stress distortion and the like. Work hardening occurs, which adversely affects the subsequent forging process for forming the clutch and rotor, and particularly causes cracking during the forging process of the inner cylindrical portion.

[0004] Therefore, as a pretreatment prior to the forging step, a step of implementing a method for eliminating stress distortion and work hardening of the inner peripheral edge of the clutch / rotor blank processed by a press machine is required. Until now, as a method, the blank is placed in a non-oxidizing annealing furnace and subjected to annealing to eliminate the work hardening of the inner peripheral edge, and the stress distortion by shaving the inner peripheral edge of the blank with a press machine. And the method of removing the part where the work hardening occurs, the method of removing the part where the stress distortion and the work hardening occur by cutting the inner peripheral edge of the blank with a lathe, etc., and the shape and other properties of the target blank respectively Is appropriately selected and executed according to

[0005] However, the above-mentioned annealing in a non-oxidizing annealing furnace involves annealing the blank for the clutch / rotor entirely, which is a measure for eliminating the cause of cracks, but the strength of the blank material is reduced. When a large number of belt-hanging grooves are formed in the outer cylindrical portion of the clutch rotor formed by this, there is a possibility that the rotor may be damaged particularly at high speed rotation. In addition, this method involves annealing not only the inner peripheral edge and the outer peripheral edge of the blank where stress distortion or work hardening occurs, but also wastes energy and increases the processing cost more than necessary.

Further, a method of shaving the inner peripheral edge of a blank where stress distortion or work hardening has occurred by a press machine is capable of adjusting the shaving allowance to the stress distortion or the work hardened layer of the inner peripheral edge of each blank. Since it is practically impossible and it is impossible to match the shape of the formed work hardened layer, the possibility that the work hardened layer or the like remains on the inner peripheral edge after the work is extremely high. Also, because of the change in the degree of wear due to the use of the shaving punch, it is difficult to control the edge finishing accuracy by removing the stress strain and the work hardened layer. For example, if the degree of wear of the shaving punch is increased and the cutting degree is deteriorated, shaving processing by this may cause new stress distortion and work hardening.

Further, in the method of cutting the inner peripheral edge of the blank using a lathe, it is difficult to make the cutting allowance correspond to the work hardened layer of each blank as in the case of the method of shaving. There is a high possibility that a work hardened layer or the like remains on the periphery. In addition, this method requires a relatively long processing time, and is not suitable for mass production.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional pretreatment method, and ensures that the stress distortion or the strain generated on the inner peripheral edge of the concentric blank for manufacturing the clutch / rotor is ensured. It is an object of the present invention to provide a method for eliminating stress distortion and work hardening of a blank for a clutch / rotor, which can eliminate work hardening and can speedily and economically perform the work without losing necessary strength. Things.

[0009]

Means for Solving the Problems 1) (claim 1) of the present invention
Is a clutch / rotor blank which is formed on a concentric blank in a pressing process of punching and drilling a hole from a predetermined metal plate material to eliminate stress distortion and surface work hardening occurring at a peripheral edge of a central hole. Wherein only the periphery of the center hole of the clutch / rotor blank is induction-heated by high-frequency induction heating, and then gradually cooled to reduce the stress-strain and processing of the clutch / rotor blank. This is a method for eliminating curing.

[0010] A second aspect of the present invention (claim 2) is the method for eliminating stress distortion and work hardening of the clutch / rotor blank according to the first aspect of the present invention, wherein heating of only the periphery of the center hole by high-frequency induction heating is performed. A plurality of inductor coils for heating the upper part of the periphery of the hole receiving the supply of the high-frequency current from the high-frequency power supply device, and the same number of inductor coils for heating the lower part of the periphery of the hole are alternately arranged. In the meantime, the clutch / rotor blank is sequentially aligned with the center hole of the inductor coil for heating the upper portion of the hole periphery above the center of the inductor, while the center hole of the blank is vertically aligned with each inductor coil.
The above-described inductor coil for heating the lower part of the periphery of the hole is moved immediately above it while being temporarily stopped, and the center of the blank for the clutch / rotor is heated by the inductor coil for heating the upper part of the hole periphery during each pause. High-frequency induction heating of the upper portion of the hole periphery is performed, and high-frequency induction heating of the lower portion of the center hole periphery of the clutch / rotor blank is performed by an inductor coil for heating the lower portion of the hole periphery. When the high-frequency induction heating by the inductor coil at the last end of the inductor coil row is completed, uniform heating of the periphery of the center hole of the clutch / rotor blank to the required temperature is performed. It is intended to be completed.

[0013] A third aspect of the present invention (claim 3) is the method for eliminating stress distortion and work hardening of the clutch / rotor blank according to the first or second aspect of the present invention, wherein the gradual cooling is performed on the clutch / heater whose heating has been completed. This is performed by storing the rotor blank in a heat insulation box and leaving it to stand.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention basically relates to a clutch
The stress distortion of the clutch / rotor blank, which eliminates the stress distortion and work hardening occurring at the periphery of the center hole by induction heating only the periphery of the center hole of the rotor blank by high-frequency induction heating, and then gradually cooling the same. And a method for eliminating work hardening.

The clutch / rotor blank is formed from a predetermined metal plate material suitable for the clutch / rotor to be manufactured into a concentric blank in an outer shape punching and drilling press process, and has an outer peripheral edge and a central hole peripheral edge. Are subjected to stress distortion and work hardening due to the pressing process. In particular, the latter stress distortion and work hardening at the periphery of the central hole adversely affect the subsequent cold forging process for forming the clutch rotor.

The above-mentioned clutch / rotor blank is formed by a cold forging process to form an inner cylindrical portion in the center portion and an outer cylindrical portion in the peripheral side portion to form a clutch / rotor overhang. When the stress distortion and the work hardening occur in the peripheral edge of the central hole, there is a very high possibility that a crack will occur in the formation of the inner cylindrical portion.

The present invention, as described above, is a method for eliminating such stress distortion and work hardening at the periphery of the center hole of the clutch / rotor blank, so as not to reduce the energy efficiency and the overall strength. In view of the above, annealing is performed only on the peripheral edge of the central hole, which is a problem in the forging process.

The high-frequency induction heating only at the periphery of the center hole is as follows.
Means for performing an annealing treatment only on the peripheral edge of the center hole, which is to position the target clutch / rotor blank such that the center hole is close to the inductor coil, and then to the inductor coil. A high-frequency current of a predetermined frequency is supplied, thereby applying a high-frequency magnetic field to the periphery of the center hole of the clutch / rotor blank to generate an eddy current and generate heat due to the eddy current loss. Thus, heat is generated only at the peripheral edge of the center hole of the clutch / rotor blank, and only that portion is heated. Needless to say, the heating temperature is a temperature at which stress distortion and work hardening determined according to the material and the like can be eliminated.

The high-frequency magnetic field needs to be applied uniformly within a necessary range around the center hole of the clutch / rotor blank. It is necessary to generate a magnetic field that can be provided, and it is practically difficult to produce an inductor coil that can generate such a magnetic field.

Therefore, the inductor coil is configured so that a high-frequency magnetic field generated by the inductor coil can be applied to the periphery of the center hole of the clutch rotor blank from one side thereof. A high-frequency magnetic field is alternately applied from one side and the other side to the periphery of the center hole of the blank, and a uniform high-frequency magnetic field is applied as a whole to a necessary range of the periphery of the center hole, thereby generating heat due to eddy current loss. It can be made to occur uniformly within the required range. The high-frequency magnetic fields from one surface side and the other surface side are preferably applied alternately as described above and each time in a plurality of times. Of course, since the heating is performed uniformly, the number of times is the same for both sides.

For example, the heating by high-frequency induction heating of only the periphery of the center hole of the clutch / rotor blank having such a configuration can be realized in the following manner. That is, a plurality of inductor coils for heating the upper portion of the hole periphery and a plurality of inductor coils for heating the lower portion of the hole periphery which are supplied with the high-frequency current from the high-frequency power supply device are alternately provided. The clutch / rotor blanks are arranged, and the center holes of the clutch rotor blanks are vertically aligned with the respective inductor coils. Immediately above the inductor coil for heating the lower edge,
Each of them is moved while being temporarily stopped, and during the respective pauses, high-frequency induction heating is performed on the upper part of the center hole periphery of the blank for the clutch / rotor by the inductor coil for heating the upper part of the hole periphery, thereby heating the lower part of the hole periphery. The inductor coil performs high-frequency induction heating of the lower portion of the center hole periphery of the clutch / rotor blank, thereby gradually raising the temperature of the upper and lower portions of the center hole periphery of the clutch / rotor blank. When the high frequency induction heating by the inductor coil is completed, uniform heating of the periphery of the center hole of the clutch / rotor blank to a required temperature is completed.

In this way, the high-frequency magnetic field can be applied to the peripheral edge of the center hole of the clutch / rotor blank from the upper surface (one surface side) and the lower surface (the other surface side) a plurality of times. The uniform heating to the required temperature in the required range of the hole periphery can be satisfactorily performed. The high-frequency magnetic field with respect to the peripheral edge of the center hole of the clutch / rotor blank was uniformly applied even once each from the one side and the other side, but this was divided into a plurality of times and the temperature was increased stepwise. By doing so, it is possible to minimize the occurrence of distortion due to thermal stress.

As described above, the clutch / rotor blank should be gradually cooled as described above after appropriately heating only the peripheral edge of the center hole. This is performed by various conventional methods. be able to. For example, it can be carried out by storing it in a heat insulation box and leaving it to stand.

Therefore, according to the method for eliminating stress distortion and work hardening of the clutch / rotor blank of the present invention, only the periphery of the center hole of the target clutch / rotor blank is induction-heated by high-frequency induction heating, and then gradually cooled. By doing so, only the necessary parts are annealed. Naturally, this makes it possible to eliminate stress distortion and work hardening at the peripheral edge of the central hole. is there. Further, since the entirety of the clutch / rotor blank is not annealed, its strength is not lost. Further, since heating can be performed in a short time, it is suitable for mass production.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment to which the present invention is applied. FIG. 1 is an explanatory plan view showing a state where a clutch / rotor blank is set in a high-frequency induction heating apparatus. FIG. FIG. 3 (a) is a partial cross-sectional explanatory view of a clutch / rotor blank showing a portion requiring annealing, and FIG.
(b) is an explanatory plan view of the clutch / rotor blank showing a portion to be annealed. FIG. 4 (a) is a schematic perspective view of a clutch / rotor blank, FIG. 4 (b) is a schematic perspective view showing a member in a state where only an inner cylindrical portion is formed from the clutch / rotor blank, and FIG. 4 (c). FIG. 3 is a schematic perspective view of a clutch rotor formed by molding both an inner cylindrical portion and an outer cylindrical portion.

FIGS. 3 (a) and 3 (b) show a method for eliminating stress distortion and work hardening of the clutch / rotor blank of this embodiment.
As shown in (1), only the peripheral edge 3 of the central hole 2 of the clutch / rotor blank 1 is induction-heated by high-frequency induction heating, and then gradually cooled, so that the stress distortion generated in the peripheral edge 3 of the central hole 2 is reduced. This eliminates surface work hardening.

The clutch / rotor blank 1 of this embodiment has an outer diameter of 90 to 200 mm and a thickness of 8 to 1 mm.
It is 4 mm and formed from a steel plate. Fig. 3 (a) and (b)
As shown in the figure, in the peripheral edge 3 of the central hole 2 of the clutch / rotor blank 1, the area to be favorably annealed is about 10 mm in dimension L1 from the inner circumference near the center of the wall thickness, and near both sides. It is appropriate that the dimension L2 from the inner circumference is about 15 mm, which is the target in this embodiment. The heating temperature in the range to be annealed is set to 700 to 730 ° C. in relation to the material and the purpose of annealing.

First, the high-frequency induction heating apparatus used in this embodiment will be described. This high frequency induction heating device
As shown in FIGS. 1 and 2, two slide rails 4, 4 for linearly sliding the clutch / rotor blank 1 thereon, and a central upper part thereof along its length. .., And six clutch / rotor blanks 1, 1 along the length direction of the slide rails 4, 4.
Are simultaneously transferred at regular intervals, and a feed mechanism 6 for accurately positioning each of them directly below or directly above the inductor coils 5, 5,... And supporting the inductor coils 5, 5,. , And a device main body 8 having a power supply device for generating a high-frequency current flowing through the inductor coils 5, 5,.

The inductor coils 5, 5,...
As shown in FIGS. 1 and 2, six of them are arranged at regular intervals along the length direction of the slide rails 4, 4. As described above, the inductor coil 5 located at the upper center of the slide rails 4 and the inductor coil 5 located at the lower center
And are arranged alternately. If the first inductor coil 5 is arranged upward, it is as if the second one is arranged below and the third one is arranged above. In FIG. 1, the head is the right end, and each component is indicated as the first or second from the right end.

As shown in FIG. 2, the upper inductor coils 5, 5, 5 are respectively provided on the slide rails 4, 4 by a pair of clutches 6a, 6a of the feed mechanism 6 which are positioned by the clutches. Rotor blank 1,
1, 1 and 1 are arranged. The inductor coils 5, 5, 5 are mutually centered with the clutch rotor blanks 1, 1, 1;
The distance between the upper surface of the rotor blanks 1, 1, 1 is 1.5 mm
It is positioned so that The smaller the interval, the better the efficiency. However, in order to avoid unnecessary short circuit accidents, the interval is set in this embodiment.

As shown in FIG. 2, the lower inductor coils 5, 5, 5 are respectively provided on the slide rails 4, 4 by a pair of clutches 6a, 6a of the feed mechanism 6 which are respectively positioned by the clutches. Rotor blank 1,
1 and 1 are disposed immediately below. The inductor coils 5, 5, 5 are mutually centered with the clutch rotor blanks 1, 1, 1;
The distance between the lower surfaces of the rotor blanks 1, 1, 1 is 1.5 mm
It is positioned so that

Each of the arm members 7, 7,... Fixes the inductor coil 5 at each of the above-mentioned positions, and includes a conductor for flowing a high-frequency current from the power supply device to each inductor coil 5 therein. It is a thing.

The power supply unit includes the inductor coils 5, 5
This embodiment generates a high-frequency current to be passed through... 25 KHz in this embodiment in consideration of the above-mentioned material, dimensions and heating depth of the target clutch / rotor blank 1, and the heating time and the number of times of heating. It is configured to generate a high-frequency current having a frequency of For the same purpose, the above-mentioned required range of the clutch rotor blank 1 is finally changed to the above-described 7 range.
In order to heat to about 00 to 730 ° C., the output is
20KW for the inductor coil 5 at the middle right end) and the second inductor coil 5, and the other inductor coils 5,
For 5 ..., it is 15 KW.

As shown in FIGS. 1 and 2, the feed mechanism 6 includes six pairs, one pair of which faces the clutch / rotor blank 1 mounted on the slide rails 4, 4 in a state where the pair can face each other. Are arranged at regular intervals along the slide rails 4, 4, and the distance between the pair of opposing sandwiching pieces 6a, 6a, and the slide rails 4, 4 are increased and decreased. The forward operation and the backward operation at a constant interval in the along direction are performed in conjunction with each other.

As shown in FIG. 1, the pair of holding pieces 6a, 6a are formed to have a V-shaped or inverted V-shaped recessed face when viewed from a plane.
The clutch / rotor blank 1 located on the slide rails 4 and 4 is interposed therebetween. At this time, the clamped rotor / blank 1 is positioned at the center of the slide rails 4 in the width direction.

Each of the pair of holding pieces 6a, 6a can be positioned so that the clutch / rotor blank 1 to be held therebetween is positioned directly above or below each of the inductor coils 5 so that their mutual centers are vertically aligned. The positional relationship as follows.
As described above, the pair of holding pieces 6a, 6a are configured to perform the forward operation and the backward operation at a constant interval along the slide rails 4, 4, in conjunction with each other. Accurately match the spacing between the adjacent inductor coils 5,5.

Therefore, the clutch / rotor blank 1 placed on the slide rails 4, 4 and transferred by the parts feeder, the pusher or the like up to the predetermined interval before the pair of leading holding pieces 6a, 6a is fed. 6, the pair of holding pieces 6a, 6a move back together in the expanded state in conjunction with each other, so that the leading pair of holding pieces 6a, 6a move to that position, and then the space reduction operation is performed in conjunction with it. And the first pair of holding pieces 6a, 6a. Thereafter, the first holding pieces 6a, 6a move forward in conjunction with the other ones, and when the predetermined interval has passed, the first holding pieces 6a, 6a, The clutch / rotor blank 1 sandwiched between 6a is moved directly below the leading inductor coil 5 and is reliably positioned there.

After a predetermined time (3 seconds in this embodiment as will be described later), each of the holding pieces 6a, 6a expands in conjunction with each other, thereby being held by the pair of leading holding pieces 6a, 6a. The clutch / rotor blank 1 is left on the slide rails 4 and 4 immediately below the leading inductor coil 5. In this state, each of the holding pieces 6a, 6a performs a return operation in conjunction with each other, and a pair of leading holding pieces 6a, 6a
In the meantime, after the first clutch / rotor blank 1, the clutch / rotor blank 1 transferred by a parts feeder, a pusher or the like is located, and the interval is also reduced by the interlocking interval reducing operation. It is sandwiched between the pair of leading holding pieces 6a, 6a, and is transported immediately below the leading inductor coil 5 following the above-described process, and is reliably positioned there.

The first clutch / rotor blank 1 which has been conveyed immediately below the leading inductor coil 5 again has a pair of leading clamping pieces 6a, 6a again, as described above, with a new clutch rotor. When the rotor blank 1 is clamped, the rotor blank 1 is simultaneously clamped by the second pair of clamping pieces 6a, 6a. It is transferred directly above the second inductor coil 5 by the holding pieces 6a, 6a, and is reliably positioned there.

In the same manner, the first clutch / rotor blank 1 is sequentially replaced with a pair of adjacent holding pieces 6a, 6a.
a, immediately below the third inductor coil 5, immediately above the fourth inductor coil 5, directly below the fifth inductor coil 5,
It is transported directly above the sixth inductor coil 5 and is further pushed backward. When starting operation, one clutch
Although only the rotor blanks 1 are transferred, the number that can be transferred simultaneously increases sequentially, and after the sixth one is received, the transfer of six simultaneously is always performed. In this feed mechanism 6, one section (between adjacent inductor coils 5, 5)
Is less than 0.5 seconds. However, since the pair of holding pieces 6a, 6a of the feed mechanism 6 reciprocate,
After the stop time of 3 seconds, it takes 1 second to transfer to the next position of the inductor coil 5.

In this embodiment, as described above,
On the entrance side of the feed mechanism 6, that is, on the slide rails 4 on the right side in FIG. 1, the clutch to be heated is moved from the leading inductor coil 5 to a position in front of the adjacent inductor coil 5 by a distance. -The rotor blank 1 is fed by a parts feeder and a pusher (not shown).
A chute 9 for sliding down the heated clutch / rotor blank 1 is connected to the outlet side of the feed mechanism 6, that is, the end of the left slide rails 4 and 4 in FIG. A container for receiving the heat-treated clutch / rotor blank 1 is provided.

This embodiment is carried out as follows using the above-described high-frequency induction heating apparatus and some other appliances. First, the clutch / rotor blank 1 to be processed is
As shown in FIG. 1, the leading inductor coil 5 is supplied by the parts feeder and the pusher to a position one section before the leading inductor coil 5 and stands by. When the clutch / rotor blank 1 is sequentially transferred from here to the high-frequency induction heating device by the feed mechanism 6, the blank 1 is subsequently supplied to the same position and stands by.

As described above, the clutch / rotor blank 1 waiting at the above-mentioned position is first transported immediately below the leading inductor coil 5 by the pair of leading holding pieces 6a, 6a of the feed mechanism 6, as described above. It is accurately positioned at this position. That is, the clutch / rotor blank 1 is positioned in a state where the center of the center hole 2 is exactly vertically aligned with the center of the inductor coil 5.

At the same time as the positioning, a high-frequency current of 25 KHz is supplied from the power supply to the leading inductor coil 5, and the peripheral edge 3 of the central hole 2 of the clutch rotor blank 1 positioned immediately below the inductor coil 5. A high-frequency magnetic field is applied from the upper surface side to generate heat mainly due to eddy current loss on the upper surface side. The output from the power supply at this time is 20 kW as described above. The high-frequency current flows through the inductor coil 5 for 3 seconds, and the high-frequency magnetic field generated by the high-frequency current is naturally applied to the peripheral edge 3 of the center hole 2 of the blank 1 for 3 seconds from above.

After the lapse of 3 seconds, the clutch / rotor blank 1 is transferred to the position immediately above the second inductor coil 5 by the second pair of holding pieces 6a, 6a as described above. Is accurately positioned. At the same time, a new clutch / rotor blank 1 is carried directly below the leading inductor coil 5 by the pair of leading holding pieces 6a, 6a, and is accurately positioned at that position. In this embodiment, since the transfer operation is a simple short-range reciprocating operation, the transfer operation is performed in about one second by the feed mechanism 6.

As described above, when the clutch / rotor blank 1 is positioned exactly immediately below the first inductor coil 5 and immediately above the second inductor coil 5, respectively, the first and second blanks are respectively obtained. Inductor coil 5,5
In the same manner, a high-frequency current of 25 KHz is applied,
Lasts for seconds. Its output is 20 kW.

Accordingly, a high frequency induction magnetic field is applied to the peripheral edge 3 of the center hole 2 from the lower surface side of the clutch / rotor blank 1 disposed immediately above the second inductor coil 5, and the lower surface side is mainly caused by eddy current loss. This produces an exotherm. Thus, the clutch / rotor blank 1 located immediately above the second inductor coil 5 is heated to substantially the same temperature on both sides at the peripheral edge 3 of the central hole 2.

On the other hand, at the same time, the high-frequency magnetic field is applied to the upper surface of the clutch / rotor blank 1 positioned immediately below the leading (first) inductor coil 5 as described above. Heat is generated by the generated eddy current loss.

After the lapse of three seconds, the clutch / rotor blank 1 located immediately above the second inductor coil 5 is moved by the third pair of holding pieces 6a, 6a as described above. It is transferred directly below the third inductor coil 5 and is accurately positioned at that position. First and second
The pair of holding pieces 6a, 6a,... Operate as described above.

When the clutch / rotor blank 1 positioned immediately below the third inductor coil 5 is positioned as described above, a high-frequency current of 25 KHz flows through the inductor coil 5 and this is also applied. Similarly, it is continued for 3 seconds.
However, its output is 15KW. Of course, a high-frequency current of 25 KHz is simultaneously supplied to the first and second inductor coils 5 and 5 and, of course, continues for 3 seconds. Its output is 20 kW, as described above.

Thereafter, the clutch / rotor blank 1 to which a high-frequency magnetic field is applied for 3 seconds immediately below the third inductor coil 5 is subsequently moved by a fourth pair of holding pieces 6a, 6a. It is transferred and positioned just above the fifth inductor coil 5, where a high-frequency magnetic field is applied for 3 seconds, and further moved by a fifth pair of holding pieces 6 a, 6 a.
It is transferred and positioned immediately below the second inductor coil 5,
Here, a high-frequency magnetic field for 3 seconds is applied, and furthermore, it is transferred and positioned just above the sixth inductor coil 5 by the sixth pair of holding pieces 6a, 6a, where a high-frequency magnetic field for 3 seconds is applied. .

The frequency, output power, and duration of the high-frequency current flowing through the third and subsequent inductor coils 5 are the same, that is, 25 KHz, 15 KW, and 3 seconds. Because of the positional relationship between the third to sixth inductor coils 5, 5,..., The high-frequency magnetic field is alternately applied from the upper surface side and the lower surface side, and the temperature gradually and averagely increases, and finally, The blank 1 for the clutch / rotor can realize heating of approximately 700 to 730 ° C. in the peripheral edge 3 of the center hole 2. One side and the other side are alternately heated. However, one side is three times and the other side is three times, and the temperature is gradually increased in small increments. Etc. can be almost suppressed.

Following the above-described first clutch / rotor blank 1, a pair of holding pieces 6a, 6a of the feed mechanism 6 are provided.
.. And the clutch / rotor blank 1 which is fed and positioned immediately below or directly above the corresponding inductor coil 5 in sequence.
It is needless to say that the heat treatment is also performed through the same process as that of the first clutch / rotor blank 1.

A high frequency magnetic field is applied by the sixth inductor coil 5 and the heated clutch / rotor blank 1 is heated as follows:
When the next clutch / rotor blank 1 is carried just above the sixth inductor coil 5, it is pushed backward at the rear ends of the sixth pair of holding pieces 6a, 6a, and slides down the chute 9. The heat-treated clutch / rotor blank 1 is collected in a container for receiving the blank.

The heat-treated clutch / rotor blanks 1, 1,... Accumulated in the container are periodically taken out together with the container, placed in a heat-insulating box, left for about 4 hours, and gradually cooled.

In this manner, only the peripheral edge 3 of the central hole 2 of the clutch / rotor blank 1 has a high-frequency magnetic field from the upper surface (one surface side) and the lower surface (the other surface side) each of which has a strong magnetic field at first and then a strong magnetic field, respectively. Each time is given a weaker magnetic field,
Within a short time, the temperature is gradually and averagely increased,
As described above, heating to a temperature of 700 to 730 ° C. is performed satisfactorily in the above-described necessary range of the peripheral edge 3 of the central hole 2, and thereafter, slow cooling is performed in a simple form. Good annealing of only the peripheral edge 3 has been completed.

[0055]

According to the method of eliminating stress distortion and work hardening of the clutch / rotor blank according to the first aspect of the present invention, induction heating is performed by applying a high-frequency magnetic field only to the periphery of the center hole of the target clutch / rotor blank. Thereafter, only the necessary portions are annealed by slow cooling, whereby stress distortion and work hardening at the periphery of the central hole can be eliminated. In addition, since the whole is not heated in this way, there is no waste of energy and it is economical. Further, since the entire structure is not annealed, the necessary strength is not lost. In addition, since heating can be performed in a short time, it is suitable for mass production.

According to the method for eliminating stress distortion and work hardening of the clutch / rotor blank according to the second aspect of the present invention, the upper surface side (one surface side) and the lower surface side (other side) of the center hole periphery of the clutch / rotor blank. The high-frequency magnetic field can be applied from the same side a plurality of times, and uniform heating to the required temperature in the required range of the periphery of the central hole can be satisfactorily performed as described above. Also, by applying a high-frequency magnetic field to the periphery of the center hole of the clutch / rotor blank from the one side and the other side several times, and increasing the temperature in stages, the occurrence of distortion due to thermal stress is minimized. Can be suppressed.

According to the method for eliminating the stress distortion and the work hardening of the clutch / rotor blank according to the third aspect of the present invention, it is possible to satisfactorily perform slow cooling with a simple tool.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view showing a state where a clutch / rotor blank is set in a high-frequency induction heating device.

FIG. 2 is an explanatory sectional view taken along line AA of FIG. 1;

FIG. 3 (a) is a partially sectional explanatory view of a clutch / rotor blank showing a portion requiring annealing. (b) is a plane explanatory view of a clutch / rotor blank showing an annealing required portion.

FIG. 4A is a schematic perspective view of a clutch / rotor blank. (b) is a schematic perspective view showing a member at a stage where only an inner cylindrical portion is formed from a clutch / rotor blank. (c) is a schematic perspective view of a clutch rotor formed by molding both an inner cylindrical portion and an outer cylindrical portion.

[Description of References] 1 Blank for clutch / rotor 2 Center hole 3 Peripheral edge 4 Slide rail 5 Inductor coil 6 Feed mechanism 6a Nipping piece 7 Arm member 8 Device body 9 Chute

Claims (3)

[Claims] A clutch and a concentric blank formed in a pressing process of punching and punching an outer shape from a predetermined metal plate material.
A method for eliminating stress distortion and work hardening of a clutch / rotor blank which eliminates stress distortion and surface work hardening occurring at a peripheral edge of a center hole of the rotor blank, comprising: A method for eliminating stress distortion and work hardening of a clutch / rotor blank by induction heating only high frequency induction heating and then gradually cooling. 2. An inductor coil for heating a plurality of upper portions of the periphery of a hole receiving a supply of a high-frequency current from a high-frequency power supply device, and an inductor for heating the upper portion of the periphery of the hole. Inductor coils for heating the lower part of the periphery of the same number of coils are alternately arranged. The blanks for the clutch / rotor are sequentially aligned with the above-described holes in the above arrangement while aligning the center holes thereof with the respective inductor coils. The inductor coil for heating the upper part of the peripheral edge is moved immediately below the inductor coil for heating the lower part of the peripheral edge of the hole. Induction heating of the upper part of the center hole periphery of the clutch / rotor blank is performed by the inductor coil for heating, and the induction coil is heated by the inductor coil for heating the lower part of the hole periphery. High-frequency induction heating of the lower portion of the center hole periphery of the rotor blank, thereby gradually increasing the temperature of the upper and lower portions of the center hole periphery of the clutch / rotor blank. The stress distortion and work hardening of the clutch / rotor blank according to claim 1, wherein the heating is completed so that uniform heating of the peripheral edge of the center hole of the clutch / rotor blank to a required temperature is completed. How to resolve. 3. The clutch / rotor blank according to claim 1 or 2, wherein the cooling is performed by storing the heated clutch / rotor blank in a heat insulation box and leaving the blank. How to eliminate hardening.