JP2012233218A - Method and apparatus for induction heating profiled cylindrical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for induction heating a profiled cylindrical member by which the profiled cylindrical member can be uniformly heated by using an induction heating coil having simple shape.SOLUTION: A workpiece 10 is a profiled cylindrical member having a first thick part 11, a second thick part 12 and a thin part 13. The induction heating coil includes a coil body 20 having a width size L1 which is set according to the width size W1 of the workpiece 10. The method for induction heating the profiled cylindrical member comprises: a first heating step of stopping the coil body 20 at a first heating position and heating the first thick part 11; a first moving step of relatively moving the coil body 20 from the first heating position to a second heating position; a second heating step of stopping the coil body 20 at the second heating position and heating second thick part 12; and a second moving step of relatively moving the coil body 20 from the second heating position to the first heating position. The above series of the steps are repeatedly performed. and every time the one series of the steps is performed, electrical power supplied to the induction heating coil is reduced step by step to uniformly heat the workpiece 10.

Description

  The present invention relates to an induction heating method and an induction heating apparatus for a deformed cylindrical member that uniformly heats a cylindrical member having a deformed cross section, such as an inner ring and an outer ring of a bearing.

  A bearing ring, such as a deep groove ball bearing, has a groove formed in order to hold a rolling element such as a ball. For this reason, the cross-sectional shape of the raceway ring is a deformed shape with a small thickness on the center side in the width direction (axial direction) of the raceway ring and a large end portion side.

  In order to uniformly heat the entire mass-produced machine part (workpiece) such as the bearing ring of this bearing, it has been conventionally performed by so-called “submerged quenching” using an atmospheric furnace (see paragraph 0002 of Patent Document 1). .

JP-A-5-202414

  However, in case of quenching using an atmospheric furnace, the production efficiency is poor because the in-process inventory must be processed after waiting for the in-process inventory. There is also a problem that the heating temperature varies depending on the position of the workpiece placed in the furnace, and the workpiece cannot be uniformly heated.

  Therefore, a method of heating the bearing ring by using a high frequency induction heating coil capable of heating the workpieces one by one can be considered. However, such induction heating is conventionally performed for quenching the workpiece surface, and does not heat the entire workpiece. In particular, when an irregularly shaped cylindrical member having a portion with a different thickness, such as the race, is induction heated using a heating coil, it is difficult to uniformly heat the entire workpiece because the thickness is different.

The present inventor has also devised a method for uniformly heating the entire deformed cylindrical part by creating a heating coil having a shape that matches the cross-sectional shape of the workpiece.
However, in this case, the heating coil must be created in accordance with the workpiece shape. For this reason, there existed a problem that a work shape became complicated and man-hours and labor were required for manufacture of a coil. Furthermore, when changing the type of workpiece to be heated, a heating coil that matches the workpiece must be manufactured and replaced. Therefore, there is a problem that the burden of coil manufacturing work is large, and the man-hours and costs increase.

  An object of the present invention is to provide an induction heating method and an induction heating apparatus for a deformed cylindrical member capable of uniformly heating a deformed cylindrical part using an induction heating coil having a simple shape.

  The present invention is a method of induction heating a deformed cylindrical member with an induction heating coil, wherein the deformed cylindrical member is provided at a first thick portion provided at one end in the axial direction and at the other end. And the induction heating coil has an axial direction of the deformed cylindrical member. The second thick portion is formed between the thick portion and a thin portion having a thickness smaller than that of the thick portion. A ring-shaped coil main body having a width dimension set according to the width dimension along the line, and the coil main body is stopped at a first heating position for heating the first thick part. A first heating step of supplying and heating the first thick part; and the coil body is moved from the first heating position to a second heating position for heating the second thick part with respect to the deformed cylindrical member. A first moving step that moves relatively, and a state in which the coil body is stopped at the second heating position. A second heating step of supplying electric power to heat the second thick part, and moving the coil body relative to the deformed cylindrical member from the second heating position to the first heating position. A second moving step, and repeatedly executing a series of steps of the first heating step, the first moving step, the second heating step, the second moving step, and each time the series of steps is executed, The deformed cylindrical member is uniformly heated by gradually reducing the power supplied to the induction heating coil.

According to the present invention, in the first heating step and the second heating step of heating the first thick part and the second thick part of the deformed cylindrical member, the ring-shaped coil body is heated in a stopped state. Therefore, a thick part with a large thickness dimension can be heated sufficiently.
Moreover, since the width dimension of the coil main body is set according to the width dimension of the deformed cylindrical member, it is possible to prevent the thin portion from overheating. That is, when the width dimension of the coil body is increased, the intermediate portion between the first thick portion and the second thick portion is heated during any stop heating, and may be overheated. Therefore, in the present invention, the overheating of the thin portion can be prevented by setting the width dimension of the coil main body so that there is no portion that is heated during both stop heatings.
Furthermore, every time a series of steps of the first heating step, the first moving step, the second heating step, and the second moving step is performed, the power supplied to the induction heating coil is gradually reduced, so that the target temperature is reached. The temperature control when approaching can be performed with high accuracy.

  In the present invention, in the first heating step and the second heating step, the temperature of the thick portion to be heated is measured, and when the measured temperature reaches the target temperature, the heating step is terminated and the moving step is executed. In the first moving step and the second moving step, it is preferable to measure the temperature of the thin wall portion and stop the power supply to the induction heating coil when the measured temperature reaches the target temperature.

According to the present invention, since the temperature of the thick part to be heated is measured in each heating step, the thick part can be accurately heated to the target temperature. Moreover, since the temperature of a thin part is measured also in each moving process, it can grasp | ascertain correctly whether the thin part reached | attained target temperature.
For this reason, since each temperature is measured directly compared with the case where each heating process is controlled by time using a timer, the heating can be controlled accurately.

  In the present invention, when the first heating step and the second heating step are performed for the first time, it is preferable that when the first set temperature lower than the target temperature is reached, the heating step is terminated and the moving step is performed. .

  According to the present invention, each of the first heating step and the second heating step becomes a moving step when heated to the first set temperature lower than the target temperature, and thus is heated in the deformed cylindrical member. The temperature difference between the portion and the other portions can be prevented from becoming extremely large, and the deformed cylindrical member can be heated in a balanced manner.

  In this invention, it is preferable that the width dimension of the coil main body of the said induction heating coil is 1/4 or more and 1/2 or less of the width dimension of the said deformed cylindrical member.

  According to the present invention, since the coil body can be set to an appropriate size, it is possible to sufficiently raise the temperature of the deformed cylindrical member and to prevent overheating of the intermediate portion in the width direction of the deformed cylindrical member.

  The induction heating device for a deformed cylindrical member according to the present invention includes a first thick part provided at one end in the axial direction, a second thick part provided at the other end, and between each thick part. An induction heating device for induction heating of a deformed cylindrical member having a thin wall portion having a thickness smaller than that of the thick wall portion, and supplying power to the induction heating coil and the induction heating coil A power supply means for changing the power supply stepwise, and a moving means for relatively moving at least one of the deformed cylindrical member and the induction heating coil in the axial direction, the induction heating coil Has a ring-shaped coil body having a width dimension set according to the width dimension along the axial direction of the deformed cylindrical member.

  Also, in the induction heating apparatus for a deformed cylindrical member according to the present invention, the moving means is configured to perform second heating for heating the second thick part from the first heating position for heating the coil main body. A first moving step of moving relative to the deformed cylindrical member to a position, and moving the coil body from the second heating position to the first heating position relative to the deformed cylindrical member. A second moving step, wherein the power supply means supplies power in a state where the coil body is stopped at the first heating position to heat the first thick portion. And a second heating step of heating the second thick part by supplying electric power in a state where the coil body is stopped at the second heating position, the first heating step, A series of steps of a 1 movement process, a 2nd heating process, and a 2nd movement process is performed. DOO, it is preferable to reduce the power supplied stepwise to the induction heating coil.

  Furthermore, in the induction heating apparatus for the irregular cylindrical member of the present invention, it is preferable that the width dimension of the coil body of the induction heating coil is not less than 1/4 and not more than 1/2 of the width dimension of the irregular cylindrical member.

  In these irregular cylindrical member induction heating apparatuses, the same effects as those of the irregular cylindrical member induction heating method can be obtained.

The side view which shows the induction heating apparatus in 1st Embodiment of this invention. The top view which shows the induction hardening apparatus in 1st Embodiment. Sectional drawing which shows the workpiece | work and coil main body in 1st Embodiment. (A) is sectional drawing which shows the 1st heating process in 1st Embodiment, (B) is sectional drawing which shows a 2nd heating process. (A) is a graph which shows the temperature change of the workpiece | work in 1st Embodiment, (B) is a graph which shows the movement position of a workpiece | work, (C) is a graph which shows the electric power supply supplied to a coil. (A) is sectional drawing which shows the 1st heating process in the comparative example 1, (B) is sectional drawing which shows a 2nd heating process. (A) is sectional drawing which shows the 1st heating process in the comparative example 2, (B) is sectional drawing which shows a 2nd heating process. (A) is sectional drawing which shows the 1st heating process in 2nd Embodiment, (B) is sectional drawing which shows a 2nd heating process. The top view which shows the induction heating coil and workpiece | work in 3rd Embodiment. (A) is sectional drawing which shows the 1st heating process in 3rd Embodiment, (B) is sectional drawing which shows a 2nd heating process.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[Overall configuration of induction heating device]
FIG. 1 is a side view showing a schematic configuration of an induction heating apparatus 1 in the present embodiment, and FIG. 2 is a plan view thereof.
As will be described later, the induction heating device 1 of the present embodiment heats a bearing race (inner ring, outer ring) as a work 10.

  The induction heating device 1 includes an induction heating coil 2, a control box 3, a workpiece holding device 4 that holds the workpiece 10, a workpiece moving device 5 that moves the workpiece 10 after heat treatment, and a workpiece 10 after heat treatment. An oil tank 6 in which cooling oil to be cooled is placed and a table 7 are provided.

[Work configuration]
FIG. 3 is a cross-sectional view of an inner ring of a bearing that is an example of the workpiece 10. As shown in FIG. 3, the workpiece 10 includes a first thick portion 11 and a second thick portion 12 at both ends in the width direction (axial direction) of the workpiece 10. For this reason, between each thick part 11 and 12, it is set as the thin part 13 with a small thickness dimension compared with the thick parts 11 and 12. FIG.
For this reason, the workpiece 10 is a cylindrical member having an irregular cross-sectional shape.

[Configuration of induction heating coil]
The induction heating coil 2 is a single winding coil (ring coil). Specifically, as shown in FIGS. 1 and 2, the induction heating coil 2 includes a coil body 20 having a substantially cylindrical shape and a pair of lead portions 21 provided in a divided portion of the coil body 20. Yes.
As shown in FIG. 3, the width dimension L <b> 1 of the coil body 20 (the dimension in the axial direction of the workpiece 10) is set corresponding to the width dimension W <b> 1 of the workpiece 10.
That is, in this embodiment, the width dimension L1 is set to 1/4 to 1/2 (1/4 or more and 1/2 or less) of the width dimension W1. In FIG. 3, L1 = W1 × 2/5. That is, when the width dimension W1 of the workpiece 10 is 50 mm, the width dimension L1 of the induction heating coil 2 is set to 20 mm. The ratio between the width dimension and the diameter of the workpiece 10 is not limited to the ratio shown in FIG.

  A through-hole 23 is formed in the coil body 20 of the induction heating coil 2 in at least one place in the circumferential direction, and a radiation thermometer 24 is provided outside the through-hole 23. The radiation thermometer 24 is a non-contact thermometer that measures the surface temperature of the workpiece 10 exposed through the through hole 23. The radiation thermometer 24 is connected to the control box 3, and measured temperature data is sent to the control box 3.

[Control box configuration]
The control box 3 includes a computer that controls the operation of the induction heating apparatus 1. As shown in FIG. 1, the control box 3 is placed on a table 7 and provided so as to be movable in the left-right direction in FIG.
The control box 3 is connected to the lead portion 21 of the induction heating coil 2 and an AC commercial power source (not shown). The control box 3 converts the current obtained from the AC commercial power source into a high frequency of a predetermined frequency and supplies it to the induction heating coil 2. At this time, the control box 3 can change the value of the power supplied to the induction heating coil 2 step by step. Therefore, the control box 3 constitutes power supply means.
As will be described later, the control box 3 also controls the operations of the work holding device 4 and the work moving device 5.

[Work holding device configuration]
As shown in FIGS. 1 and 2, the workpiece holding device 4 supports a workpiece support member 41 that supports the workpiece 10, a movable table 42 that rotatably supports the workpiece support member 41, and a movable table 42 that can move up and down. And a base table 43 to be used.
The work support member 41 includes a shaft portion 411 that is pivotally supported by the moving base 42 and a support arm 412 that extends from the shaft portion 411 in three directions. The distal end side of the support arm 412 is bent upward, and a flange for supporting the workpiece 10 is formed on the distal end side.

  The moving table 42 incorporates a motor (not shown) that rotates the work support member 41. This motor is controlled by the control box 3 and can rotate the work support member 41. When the work support member 41 rotates, the work 10 supported by the work support member 41 also rotates together.

The base 43 has a built-in motor 44 that moves the moving table 42 in the vertical direction. This motor 44 is also controlled by the control box 3 and can move the moving table 42 up and down.
When the moving table 42 moves up and down, the workpiece 10 moves in the axial direction with respect to the coil body 20 of the induction heating coil 2.
Therefore, the workpiece holding device 4 constitutes a moving means for moving the deformed cylindrical member as the workpiece 10 relative to the induction heating coil 2 in the axial direction.

The workpiece moving device 5 includes a feed screw 51 that is rotated by a motor 50 and a pusher 52 that is moved by the feed screw 51.
The workpiece moving device 5 moves the workpiece 10 placed on the table 7 to the oil tank 6 by the pusher 52 when the moving table 42 of the workpiece holding device 4 moves below the surface of the table 7. .
For this reason, the table 7 is formed with a groove portion 71 in which the movable table 42 and the work support member 41 can be buried.

[Heating operation by induction heating device]
Next, the heating operation of the induction heating apparatus 1 will be described.
First, the workpiece 10 to be heated is placed on the workpiece support member 41 and the heating operation is started.
Then, the control box 3 moves the moving table 42 up and down, and the coil body 20 of the induction heating coil 2 heats the first thick part 11 of the workpiece 10 as shown in FIG. The workpiece 10 is moved so as to be located at the heating position.
The first heating position is set such that the center in the width direction (axial direction) of the coil body 20 coincides with the center in the width direction (axial direction of the workpiece 10) of the first thick portion 11. For example, when the width dimension W1 of the workpiece 10 is 50 mm, the width dimension S1 of each of the thick portions 11 and 12 is 10 mm, and the width dimension L1 of the coil body 20 is 20 mm, the upper surface of the coil body 20 is 5 mm from the upper end of the workpiece 10. It arrange | positions so that it may become upper.

[First heating step: First cycle]
Then, the control box 3 performs the first heating step, while rotating the work 10 by the work support member 41, as shown in FIG. 5C, the control box 3 has a first set power P1 (for example, 250 kW) high-frequency power. Is supplied to the induction heating coil 2. When a high-frequency current flows through the induction heating coil 2, an alternating magnetic flux is generated around the coil body 20 as shown in FIG. 4A, and the workpiece 10 is induction-heated. At this time, since the coil body 20 is in the first heating position, in particular, the upper end side of the workpiece 10 provided with the first thick portion 11 is heated.
And the temperature of the 1st thick part 11 is measured with the radiation thermometer 24, and this measured value rises rapidly as shown to the continuous line 100 of FIG. 5 (A).

[First moving step: First cycle]
When the measured temperature of the first thick portion 11 reaches a set temperature T1 (for example, 700 degrees), the control box 3 moves the moving table 42 upward while continuing to supply the first set power P1 to the induction heating coil 2. The moving first moving step is executed. During this movement, the thin-walled portion 13 is also heated, so that the temperature rises as shown by a one-dot chain line 101 in FIG. However, the first thick portion 11 is heated while the coil body 20 is stopped at the first heating position, whereas the thin portion 13 is heated while moving with respect to the coil body 20 and the heating time is increased. Therefore, the temperature of the thin portion 13 does not rise to the set temperature T1.

[Second heating step: First cycle]
Then, as shown in FIG. 4B, when the coil body 20 reaches the second heating position for heating the second thick part 12, the control box 3 moves the moving base 42 (first moving step). Stop and perform the second heating step.
The second heating position is also the same as the first heating position. In the specific example, the lower end of the coil body 20 protrudes 5 mm below the lower end of the workpiece 10. Further, the moving speed of the moving table 42 in the moving process is, for example, 10 mm / sec. In the first movement step, as shown in FIG. 5B, the coil body 20 needs to be moved 40 mm from the first heating position to the second heating position, and therefore the movement time is 4 seconds.

In the second heating step, when the coil main body 20 is heating the second thick portion 12 portion, the temperature of the second thick portion 12 is measured by the radiation thermometer 24. As indicated by a two-dot chain line 102 in FIG.
On the other hand, since the first thick portion 11 is not heated away from the coil body 20, the temperature decreases as indicated by the solid line 100.

[Second movement step: First cycle]
When the measured temperature of the second thick portion 12 reaches the set temperature T1 (for example, 700 degrees), the control box 3 moves the moving base 42 downward while continuing to supply the first set power P1 to the induction heating coil 2. Moving. Even during this movement, the thin-walled portion 13 is heated, and the temperature rises as indicated by the alternate long and short dash line 101 in FIG.
Then, when the induction heating coil 2 reaches the first heating position in FIG. 4A, the movement of the moving table 42 is stopped.

[First heating step: Second cycle]
Next, the control box 3 stops the coil body 20 at the first heating position, and supplies the induction heating coil 2 with the high frequency power of the second set power P2 while rotating the work 10 by the work support member 41, The 11th thick part 11 part is heated. The second set power P2 is smaller than the first set power P1, and is, for example, 140 KW. For this reason, as for the 1st thick part 11, as shown to the continuous line 100 of FIG. 5 (A), temperature rises again. At this time, the supply power P2 to the induction heating coil 2 is lower than the first set power P1 in the previous first heating step, so that the rate of temperature rise is slow.
Moreover, since the 2nd thick part 12 part leaves | separates from the induction heating coil 2, as shown to the dashed-two dotted line 102 of FIG. 5 (A), temperature falls.

[First movement step: second cycle]
Then, when the measured temperature of the first thick portion 11 reaches the target temperature T2 (for example, 900 degrees), the control box 3 moves the moving table 42 while continuing to supply the second set power P2 to the induction heating coil 2. Move upward. During this movement, the thin portion 13 is heated and the temperature rises.

[Second heating step: Second cycle]
And the control box 3 will stop the movement of the moving stand 42, and will perform a 2nd heating process, if the coil main body 20 will be in a 2nd heating position. Then, the temperature of the second thick portion 12 rises again as indicated by a two-dot chain line 102 in FIG. Also in this case, since the power P2 supplied to the induction heating coil 2 is lower than the first set power P1 in the previous second heating step, the rate of temperature rise is slow.

[Second moving step: Second cycle]
When the measured temperature of the second thick part 12 reaches the target temperature T2, the control box 3 moves the moving base 42 downward while continuing to supply the second set power to the induction heating coil 2.
Then, when the induction heating coil 2 reaches the first heating position, the movement of the moving table 42 is stopped.
In addition, the control box 3 also measures the temperature of the thin part 13 during a movement process, and determines whether it has reached target temperature T2.

[First heating step to second moving step: third cycle]
When the temperature of the thin portion 13 does not reach the target temperature T2 during the moving process, the control box 3 switches the power supplied to the induction heating coil 2 to the third set power P3, The 1 movement process, the 2nd heating process, and the 2nd movement process are performed one by one.
The third set power P3 is smaller than the second set power P2, and is 95 KW, for example. For this reason, the temperature rise in each heating process is moderate as compared with the second cycle.
Further, as in the second cycle, the control box 3 continues each heating process until the measured temperatures of the first thick part 11 and the second thick part 12 reach the target temperature T2, and moves to the target temperature T2. Execute.
Furthermore, the control box 3 also measures the temperature of the thin portion 13 during the moving process, and determines whether the target temperature T2 has been reached.

[First heating step to second moving step: fourth cycle]
When the temperature of the thin portion 13 does not reach the target temperature T2 during the moving process, the control box 3 switches the power supplied to the induction heating coil 2 to the fourth set power P4, The 1 movement process, the 2nd heating process, and the 2nd movement process are performed one by one.
The fourth set power P4 is smaller than the third set power P3, and is 60 KW, for example. For this reason, the temperature rise in each heating step is moderate as compared with the third cycle.
Further, as in the third cycle, the control box 3 continues each heating process until the measured temperature of the first thick part 11 and the second thick part 12 reaches the target temperature T2, and moves to the target temperature T2. Execute.
Furthermore, the control box 3 also measures the temperature of the thin portion 13 during the moving process, and determines whether the target temperature T2 has been reached.

In the example of FIG. 5A, the temperature of the thin portion 13 has reached the target temperature T2 in the second moving step of the fourth cycle. As a result, the entire workpiece 10 is also uniformly heated to the target temperature T2.
Therefore, the control box 3 stops the power supply to the induction heating coil 2.
In the fourth cycle, when the thin wall portion 13 does not reach the target temperature T2, the power to the induction heating coil 2 is further reduced by one step, and the first heating step, the first moving step, the second step What is necessary is just to repeat a heating process and a 2nd movement process.

[Cooling process]
When the control box 3 stops supplying power to the induction heating coil 2, the support arm 412 of the work support member 41 is aligned with the groove 71 of the table 7, and the moving table 42 is moved below the surface of the table 7. Then, the work 10 is placed on the surface of the table 7.
Next, the control box 3 operates the motor 50 of the workpiece moving device 5 to move the pusher 52 and conveys the workpiece 10 to the oil tank 6. Then, the workpiece | work 10 is immersed in the cooling oil of the oil tank 6, and is cooled. Thereby, the whole workpiece | work 10 is hardened.

According to the present embodiment as described above, the following effects can be obtained.
(1) In the present embodiment, since the width dimension L1 of the coil body 20 is set to an appropriate dimension according to the width dimension W1 of the workpiece 10, the width dimension of the coil body 20 is too long or too short. Compared to the case, the thin part 13 is not overheated, and the entire workpiece 10 can be uniformly heated without causing the temperature rise to be insufficient.
That is, in the present embodiment, the width dimension L1 of the coil body 20 is set to an appropriate dimension with respect to the width dimension W1 of the workpiece 10, specifically, 1/4 or more and 1/2 or less. As a comparative example of this embodiment, a coil body having a width as shown in FIGS.
FIG. 6 is a comparative example 1 in which the width L2 of the coil body 20A is larger than ½ of the width W1 of the workpiece 10. Specifically, when the width dimension W1 = 50 mm, the width dimension L2 = 30 mm.
FIG. 7 is a comparative example 2 in which the width L3 of the coil body 20B is smaller than ¼ of the width W1 of the workpiece 10. Specifically, when the width dimension W1 = 50 mm, the width dimension L3 = 10 mm.

In these comparative examples 1 and 2, the same heat treatment as in the above embodiment was performed.
In Comparative Example 1, since the width dimension L2 of the coil body 20A is relatively larger than the width dimension W1 of the workpiece 10, the workpiece 10 can be obtained even when the coil body 20A is disposed at the first heating position or the second heating position. An eddy current was generated by applying a magnetic flux to the intermediate portion of the axis. In addition, as for the 1st heating position and the 2nd heating position, the axial center position of coil main part 20A corresponds to the axial center position of the 1st thick part 11 and the 2nd thick part 12 like the above-mentioned embodiment. It is a position to do.
For this reason, the thin part 13 in the intermediate part of the workpiece 10 is heated and overheated in both the first heating step and the second heating step, and the entire workpiece 10 cannot be heated uniformly.
In order to prevent overheating of the thin portion 13, the position of the coil main body 20 </ b> A at the first heating position or the second heating position may be further away from the center portion of the workpiece 10. In this case, most of the magnetic flux generated by the coil main body 20A is in a no-load state, and is not used for induction heating of the workpiece 10, so that power is wasted.

  On the other hand, in Comparative Example 2, since the width dimension L3 of the coil body 20B is relatively small compared to the width dimension W1 of the workpiece 10, it is not possible to sufficiently supply electric power, and the workpiece 10 can be sufficiently heated. could not.

  In contrast to these comparative examples 1 and 2, in this embodiment, as shown in FIG. 4, the width L1 of the coil body 20 is set to a range of 1/4 to 1/2 of the width W1 of the workpiece 10. In addition, the thin portion 13 does not overheat, and the power supplied to the induction heating coil 2 can be set to an appropriate level to save power, and the life of the induction heating coil 2 can be extended.

(2) In addition, the workpiece 10 is heated in a stopped state without moving the coil body 20 in the axial direction at the first heating position and the second heating position. For this reason, even when heating the workpiece 10 of a deformed cylindrical member having the first thick part 11 and the second thick part 12, the coil body 20 can use a ring coil having a simple shape. Therefore, compared with the case where the coil of the shape according to the workpiece | work 10 is manufactured, manufacture of a coil becomes easy. Furthermore, a plurality of types of workpieces 10 having different cross-sectional shapes can be subjected to heat treatment using the same induction heating coil 2, and the cost can be reduced in this respect as well.

(3) Furthermore, the electric power supplied to the induction heating coil 2 is reduced step by step every time the first heating step and the second heating step are repeated. For this reason, the whole workpiece | work 10 can be easily adjusted to final target temperature T2. That is, by gradually reducing the power supplied to the induction heating coil 2, the temperature is rapidly increased in the initial stage, but when the temperature approaches the target temperature T2, the temperature increase can be moderated. For this reason, when the temperature approaches the target temperature T2, the entire temperature of the workpiece 10 can be accurately heated to the target temperature T2 without increasing the temperature at a stretch by the heat treatment and exceeding the target temperature T2.

(4) Moreover, even if the electric power supplied to the induction heating coil 2 is reduced stepwise, the heat applied in each heating process moves in the workpiece 10, and not only the surface of the workpiece 10 but also the entire workpiece 10. Can be heated. Therefore, the same effect as when the frequency in the high frequency induction heating process is changed can be obtained, and not only the surface of the workpiece 10 but also the entire workpiece 10 can be heated uniformly.

(5) In the present embodiment, the first (first cycle) heat treatment of the thick portions 11 and 12 is completed when the set temperature T1 lower than the target temperature T2 is reached. For this reason, each part of the workpiece | work 10 can be heated uniformly compared with the case where it heat-processes until it reaches target temperature T2 from the 1st time. That is, when only the first thick part 11 is heated to the target temperature T2 (about 900 degrees) in a state where the second thick part 12 is not heated, the temperature difference between the thick parts 11 and 12 becomes too large. Thus, it takes time to heat the entire workpiece 10 to a uniform temperature. On the other hand, in this embodiment, since it heats to setting temperature T1 in a 1st cycle and it heats to target temperature T2 after the 2nd cycle, the whole workpiece | work 10 can be heated uniformly.

(6) In this embodiment, since the workpiece 10 is heated by induction heating using the induction heating coil 2, it is not necessary to perform a predetermined number of heat treatments as in the case of heating in an atmosphere furnace. For this reason, in the present embodiment, a necessary number of heat treatments can be performed one by one, and in-line processing can be performed instead of batch processing when the workpiece 10 is manufactured.
Furthermore, in the atmosphere furnace, the heating state may vary depending on the arrangement position of the components. However, in this embodiment, since the heat treatment is performed one by one, uniform heating with little variation is possible.

(7) Since the through-hole 23 is formed in the induction heating coil 2 and the temperature can be measured with the radiation thermometer 24 from the through-hole 23, the temperature of the thick portions 11 and 12 facing the induction heating coil 2 is directly adjusted. And it can measure with high accuracy. For this reason, the precision of heating control can be improved and the whole workpiece | work 10 can be heated uniformly to target temperature T2.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
In the second embodiment, a workpiece 10B as shown in FIG. 8 is heated. The workpiece 10B is formed in an inverted R shape so that the opposing surfaces of the thick portions 11B and 12B are recessed inward.
In the workpiece 10B, the thick portions 11B and 12B are thinner than the workpiece 10, so the first heating position and the second heating position for heating the first thick portion 11B and the second thick portion 12B. Is the position shown in FIG. These heating positions are such that the end in the width direction of the coil body 20C is located inside the thick portions 11B and 12B and close to the thick portions 11B and 12B.

Specifically, in the example of FIG. 8, the width dimension W2 of the workpiece 10B = 50 mm, the width dimension S3 of each thick part 11B, 12B = 5 mm, the dimension W3 = 40 mm between the thick parts 11B, 12B, the coil body 20C. Width dimension L4 = 12.5 mm, and the relative movement amount of the coil body 20C and the workpiece 10B is 27.5 mm.
That is, the coil body 20C has a width dimension L4 of 12.5 mm and is a quarter of the width dimension W2 of the workpiece 10B.
And the coil main body 20C and the workpiece | work 10B are shown in FIG.8 (B) from the position (1st heating position) where the upper surface of the coil main body 20C shown to FIG. 8 (A) is a lower end of 1st thick part 11B. The lower surface of the coil main body 20C relatively moves to the position of the upper end of the second thick part 12B (second heating position).

In such a second embodiment, the same operational effects as the first embodiment can be obtained.
That is, stop heating is performed at the first heating position and the second heating position for heating the thick portions 11B and 12B, and the coil main body 20C is relatively moved when the thick portions 11B and 12B reach a predetermined temperature. In addition, the power supplied to the coil body 20C is reduced stepwise. For this reason, the coil main body 20C can use a single-turn coil having a rectangular cross-sectional shape. For example, the coil main body 20C has a shape as compared with the case where the coil is manufactured in accordance with the shape of the workpiece 10B having the reverse R portion. Since this is simple, the number of steps for coil production can be reduced, and the production cost can be reduced.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 9 and 10, the third embodiment heats a workpiece 10 </ b> C having a smaller diameter than the inner diameter of the coil body 20 </ b> D of the induction heating coil 2.
When the size (diameter) of the work 10C is small with respect to the induction heating coil 2, if the centers of the coil body 20D and the work 10C are aligned and arranged concentrically, the distance between the coil body 20D and the work 10C is increased. The magnetic flux generated by the induction heating coil 2 does not sufficiently flow to the workpiece 10C, and induction heating may not be possible.
For this reason, in the third embodiment, the center of the workpiece 10C is arranged in an eccentric position with respect to the center of the coil body 20D, and a part of the workpiece 10C is close to the coil body 20D.
In this case, only a portion of the workpiece 10C adjacent to the coil body 20D is heated, but the entire circumference of the workpiece 10C is uniformly heated by rotating the workpiece 10C at a predetermined speed.
In order to arrange the workpiece 10C in an eccentric position with respect to the induction heating coil 2, the control box 3 to which the induction heating coil 2 is attached may be moved back and forth for adjustment. At this time, in particular, in the coil main body 20 </ b> D of the induction heating coil 2, it is preferable that the portion on the side opposite to the lead portion 21 is disposed so as to be close to the workpiece 10 </ b> C.

  Also in the third embodiment, the axial movement of the workpiece 10C with respect to the coil body 20D can be performed in the same manner as in the first embodiment. For example, the process of moving the coil body 20D to the first heating position while heating the workpiece 10C at a predetermined speed and the process of heating the coil body 20D to the second heating position may be repeated.

  In the third embodiment, since the coil main body 20D is arranged at an eccentric position with respect to the workpiece 10C, the portion heated in the workpiece 10C is only the portion close to the coil main body 20D. For this reason, coil body 20D of 3rd Embodiment enlarges width dimension L5 so that the whole workpiece | work 10C can be heated uniformly. For example, in the example shown in FIG. 10, the coil body 20D has a width dimension L5 of 25 mm, which is as large as 1/2 of the width dimension W2 (= 50 mm) of the workpiece 10C. The relative movement amount of the coil body 20D in the axial direction with respect to the workpiece 10C may be set so that the coil body 20D moves within the range between the thick portions 11B and 12B (range of dimension W3 = 40 mm). It is. In this case, the width-direction intermediate portion of the workpiece 10C in both cases where the coil body 20D is in the first heating position shown in FIG. 10A and in the second heating position shown in FIG. 10B. The entire workpiece 10C disposed at an eccentric position with respect to the coil body 20D can be heated uniformly.

In the third embodiment, the same operational effects as those of the first embodiment can be obtained.
Furthermore, since the work 10C can be decentered with respect to the coil main body 20D by moving the control box 3, even when the size of the work 10C is small with respect to the coil main body 20D, heating can be performed uniformly.
For this reason, for example, if the diameter of the coil body 20D is 320 mm, the workpiece 10C having a diameter of about 200 to 300 mm can be heated. Thus, even when there are a plurality of types of workpieces 10C, a single coil can be used. That is, by moving the control box 3, the induction heating coil 2 can be disposed at an appropriate position with respect to the workpiece 10C having different sizes, and the entire workpiece can be heated uniformly.

[Modification of the present invention]
In addition, this invention is not restricted to the structure of the said embodiment.
For example, in each of the embodiments described above, the coil body 20 of the induction heating coil 2 is disposed on the outer peripheral side of the workpiece 10, but may be disposed on the inner peripheral side. Also in this case, induction heating is performed in a state where the coil main body is disposed and stopped at a heating position for heating one thick portion, and when the temperature reaches a predetermined temperature, the work and the coil main body are relatively moved. Then, the process of performing induction heating by stopping the coil body at the heating position for heating the other thick part may be repeated.

Moreover, as an induction heating coil, you may provide a coil main body in the outer peripheral side and inner peripheral side of the workpiece | work 10, respectively.
Furthermore, although the said workpiece | work was the inner ring | wheel of the bearing which has the projection part which protrudes to the outer peripheral side, the outer ring | wheel of a bearing which has the protrusion part which protrudes to the inner peripheral side may be sufficient.

  Moreover, you may set final target temperature T2 from a 1st cycle as target temperature which complete | finishes each heating process. However, there is an advantage that the workpiece 10 can be uniformly heated more easily when the set temperature T1 and the target temperature T2 are set stepwise as in the embodiment.

  Further, although the width dimension of the coil body is set based on the width dimension of the workpiece, it may be set in consideration of the width dimension of the thick portion. For example, the width dimension L of the coil main body may be set in a range of 1/4 to 1/2 of the width dimension W of the workpiece and 2 to 3 times the width dimension S of the thick part. Thus, if the width dimension of the thick part is taken into account, the width dimension of the coil body can be set more appropriately.

  In each of the above embodiments, the heating process is controlled while measuring the temperature of the workpiece 10 using the radiation thermometer 24. However, a preset heating time is measured with a timer without measuring the temperature of the workpiece. You may control by measuring. That is, the time until the temperature of the workpiece reaches a predetermined temperature is measured in advance using a prototype, etc., and the time of the heating process corresponding to each supply power value is set based on the measured value. When the heat treatment is performed, it may be performed by measuring the time of a timer. In this case, the radiation thermometer 24 can be dispensed with, but heating accuracy can be improved by measuring the temperature as in the above embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Induction heating apparatus, 2 ... Induction heating coil, 3 ... Control box, 4 ... Work holding | maintenance apparatus, 5 ... Work moving apparatus, 6 ... Oil tank, 7 ... Table 10, 10, 10A, 10B, 10C ... Work, 11, 11B ... 1st thick part, 12, 12B ... 2nd thick part, 13 ... Thin part, 20, 20A, 20B, 20C, 20D ... Coil body, 21 ... Lead part, 23 ... Through hole, 24 ... Radiation thermometer , 41 ... Work support member, 42 ... Moving base, 43 ... Base base, 44 ... Motor, 50 ... Motor, 51 ... Feed screw, 52 ... Pusher, 71 ... Groove, 411 ... Shaft, 412 ... Support arm.

Claims (7)

A method of induction heating a deformed cylindrical member with an induction heating coil,
The deformed cylindrical member is provided between the first thick part provided at one end in the axial direction, the second thick part provided at the other end, and the thick part. It has a thin part with a smaller thickness than the meat part,
The induction heating coil has a ring-shaped coil body having a width dimension set according to a width dimension along the axial direction of the deformed cylindrical member;
A first heating step of heating the first thick part by supplying electric power in a state where the coil body is stopped at a first heating position for heating the first thick part;
A first moving step of moving the coil body relative to the deformed cylindrical member from the first heating position to a second heating position for heating the second thick part;
A second heating step of heating the second thick part by supplying power in a state where the coil body is stopped at the second heating position;
A second moving step of moving the coil body relative to the deformed cylindrical member from the second heating position to the first heating position;
A series of steps of the first heating step, the first moving step, the second heating step, and the second moving step are repeatedly executed, and each time the series of steps is executed, electric power supplied to the induction heating coil is stepped. The method for induction heating of the irregularly shaped cylindrical member is characterized in that the irregularly shaped cylindrical member is uniformly heated to uniformly heat the deformed cylindrical member. In the induction heating method of the deformed cylindrical member according to claim 1,
In the first heating step and the second heating step, the temperature of the thick portion to be heated is measured, and when the measured temperature reaches the target temperature, the heating step is terminated and the moving step is executed.
In the first moving step and the second moving step, the temperature of the thin portion is measured, and when the measured temperature reaches the target temperature, the power supply to the induction heating coil is stopped. . In the induction heating method of the irregular cylindrical member according to claim 2,
When the first heating step and the second heating step are executed for the first time, the heating step is terminated and the moving step is executed when the first set temperature lower than the target temperature is reached. Induction heating method for members. In the induction heating method of the deformed cylindrical member according to any one of claims 1 to 3,
An induction heating method for an irregular cylindrical member, wherein a width dimension of a coil body of the induction heating coil is ¼ or more and ½ or less of a width dimension of the irregular cylindrical member. A first thick part provided at one end in the axial direction, a second thick part provided at the other end, and a thickness provided between each thick part compared to the thick part. An induction heating device for induction heating a deformed cylindrical member having a thin portion with a small thickness,
An induction heating coil;
Power supply means for supplying power to the induction heating coil and changing the supply power in stages;
Moving means for relatively moving at least one of the deformed cylindrical member and the induction heating coil in the axial direction;
The induction heating coil includes a ring-shaped coil body having a width dimension set in accordance with a width dimension along the axial direction of the irregular cylindrical member. In the induction heating device for a deformed cylindrical member according to claim 5,
The moving means is
A first moving step of moving the coil body relative to the deformed cylindrical member from a first heating position for heating the first thick part to a second heating position for heating the second thick part. When,
Performing a second movement step of moving the coil body relative to the deformed cylindrical member from the second heating position to the first heating position;
The power supply means
A first heating step of heating the first thick part by supplying power in a state where the coil body is stopped at the first heating position;
Performing a second heating step of heating the second thick part by supplying electric power in a state where the coil body is stopped at the second heating position;
Each time the series of steps of the first heating step, the first moving step, the second heating step, and the second moving step is executed, the power supplied to the induction heating coil is reduced stepwise. Induction heating device for cylindrical members. In the induction heating apparatus for a deformed cylindrical member according to claim 5 or 6,
The induction heating device for an irregular cylindrical member, wherein a width dimension of a coil body of the induction heating coil is ¼ or more and ½ or less of a width dimension of the irregular cylindrical member.

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