JPH08176651A - High-frequency heating coil - Google Patents

Abstract

PURPOSE: To prevent a range to be heated from reaching the inside of each end part of a work, and simplify the heating work when the inner side of a cylindrical work is heated. CONSTITUTION: A heating conductive body 41a of a coil body 41 is inserted in a work 10. Concentric rings 42, 42 are provided on each end side in the axial direction of the heating conductive body 41. The concentric rings 42, 42 are connected and fixed to the coil body 41 by a supporting means 43. Magnetic flux is prevented from spreading on the each end side of the heating conductive body by the concentric rings 42, 42. The concentric rings 42, 42 are inserted in each end part of the work 10 as the coil body 41 is inserted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency heating coil for heating the inner surface of a cylindrical work such as a bearing case by induction heating.

[0002]

2. Description of the Related Art A bearing case of a ball bearing is generally subjected to a quenching treatment in order to suppress abrasion of the inner surface with which the ball comes into contact. In the quenching, high frequency induction heating is usually used for heating the inner surface. FIG.
The conventional heating coil used for heating the inner surface of the bearing case and the heating method using the coil are shown in FIG.

The work 10 is a cylindrical bearing case used in a steering system of an automobile. Work 1
On the inner surface of 0, a U groove 11 into which a large number of balls are fitted is provided in two stages. Further, notches 12 having a larger inner diameter than the other portions are continuously provided in the circumferential direction on the inner surfaces of both ends of the work 10. The heating coil 20 for heating the inner surface of the work 10 includes a circular heating conductor 21 that is concentrically inserted into the work 10 and a pair of lead conductors 22 that extend from the heating conductor 21 in the axial direction. Here, the heating conductors 21 are provided in two stages corresponding to the U groove 11.

When heating the work 10, the work 1
The work 10 is placed on the lower outlet ring 30 which also serves as the pedestal of 0, and the upper outlet ring 30 is placed on the work 10. Top and bottom outlet ring 30
In each case, the inner peripheral portion is fitted into the cutout portion 12 of the work 10. When the setting of the work 10 is completed in this way, the heating conductor 21 of the heating coil 20 is inserted inside the work 10, and a high frequency current is passed through the heating conductor 21 via the lead conductor 22 while rotating the work 10 in the circumferential direction. The current-carrying path includes one lead conductor 22, one heating conductor 21, the other heating conductor 21, and the other lead conductor 2.
The order is 2.

Due to this energization, a high frequency induction current is generated on the inner surface of the work 10 and the work 10 including the inner surface of the U groove 11 is generated.
The inner surface is heated. The heating range is shown by cross-hatching in the figure. If heating is performed without using the upper and lower concentrator rings 30, the magnetic flux generated from the heating conductor 21 spreads to both ends in the axial direction of the work 10, and as a result, the heating range is reduced as shown by the broken line in the figure. , Stepped notch 1
Reach the boundary with 2. In that case, a hardness difference occurs at the boundary where stress is concentrated, and cracks are likely to occur at this part. That is, the upper and lower concentrator rings 30 prevent the magnetic flux from spreading to both ends of the heating conductor 21 and prevent the heating range from reaching the boundary with the notch 12. The outlet ring 30 is made of a conductor and is insulated from the work 10 by a ceramic chip or the like (not shown).

[0006]

In the conventional heating coil 20 as described above, by using the outlet ring 30 together, it is possible to prevent the heating range from reaching the step portion formed on the inner surface of both end portions of the work 10. it can. Here, of the upper and lower outlet rings 30, the lower outlet ring 30
Since it also serves as a stand for the work 10, it does not adversely affect workability. However, the upper outlet ring 30 needs to be placed on the work 10 or removed from the work 10 each time the work 10 is heated, which is a major cause of deterioration in workability of the heating work. Further, since the position of the outlet ring 30 is affected by the end shape of the work 10, the outlet ring 30 may be far away from the heating conductor 21 depending on the end shape, and the magnetic flux suppressing effect may not be sufficient. .

The present invention was devised in view of the above circumstances, and effectively prevents the heating range from expanding to the inner surfaces of both ends of the work by using the outlet ring, and is the same as when the outlet ring is not used. An object of the present invention is to provide a high frequency heating coil that can perform heating with workability.

[0008]

A high-frequency heating coil of the present invention is a high-frequency heating coil for heating the inner surface of a cylindrical work by induction heating, and is inserted concentrically on the inner surface of the work. A coil main body having a circular heating conductor facing the inner surface thereof, and a lead conductor extending in the axial direction from the heating conductor for energizing the heating conductor, and both ends in the axial direction of the heating conductor. To prevent the magnetic flux from spreading to the side thereof, a pair of outlet rings arranged at both ends in the axial direction thereof and a pair of support members respectively supporting the pair of outlet rings from inside are connected by a connecting member to form a pair of support members. And a ring supporting means for connecting at least one of the connecting members to the coil body.

Preferably, a concentrating means for adjusting the pair of supporting members to be movable in the axial direction with respect to the connecting member is provided. Specifically, the connecting member of the ring supporting means is a bolt located at the axial center portion of the heating conductor, the bolt is rotatably connected to the lead conductor of the coil body, and the pair of supporting members is connected to the bolt. It is not a nut member that is screwed into the above, and the lead conductor is made to penetrate through one support member.

[0010]

In the high-frequency heating coil of the present invention, since the pair of outlet rings are connected and integrated with the coil body, when the coil body is inserted into the work, the outlet rings are also inserted inside both ends of the work as the coil body is inserted. To be done. Further, the insertion position of the concentrator ring is not affected by the shape of the end portion of the work. Then, during heating, it is possible to effectively prevent the heating range from expanding to the inner surfaces of both ends of the work due to the concentrating. When the concentrator position adjusting means is provided, the concentrator position can be adjusted in the axial direction.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a longitudinal sectional view of a high frequency heating coil showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG.

The main coil 40 is a cylindrical work 10.
It is used to heat the inner surface of. The work 10 is the same bearing case for an automobile as shown in FIG. 3, and has a two-step U-groove 11 on the inner surface of the central portion and notches 12 on the inner surfaces of both ends.

The main constituent members of the coil 40 are a coil body 41, a pair of outlet rings 42, and a support means 43 for the outlet rings 42.

The coil body 41 has the same structure as the conventional heating coil 20 shown in FIG. 3, and has two upper and lower heating conductors 41a corresponding to the heating conductor 21 and a pair of lead conductors corresponding to the lead conductor 22. 41b.

The upper and lower heating conductors 41a are concentrically inserted into the work 10 and face the U-grooves 11 formed on the inner surface of the work 10 in the upper and lower stages. Pair of lead conductors 41b
Is located inside the heating conductor 41a, extends upward along the axis of the heating conductor 41a, and is connected to a high-frequency power source (not shown).

Here, the coil body 41 is made of a copper circular tube, and the high frequency current supplied from the power source is one lead conductor 41b, one heating conductor 41a, and the other heating conductor 41.
a, the other lead conductor 41b flows in this order, and the cooling water flows inside.

The pair of outlet rings 42 are made of a conductor having the same inner and outer diameters as the heating conductor 41a.
The heating conductor 41a is concentrically supported above and below the heating conductor 41a by the supporting means 43 so that when the 1a is inserted into the work 10, it is positioned inside both ends of the work 10.

The support means 43 includes two upper and lower support members 43a for supporting the upper and lower outlet rings 42 from the inside.
Upper and lower support members 43a located at the axial center of the heating conductor 41a
And a connecting member 43b that connects them by penetrating the central part of the. Each of these is made of an insulating material such as glass laminate or bake.

The connecting member 43b is a bolt having an external thread on its outer surface. The upper end portion is rotatably connected to the lead conductor 41b by a support member 43c.
The upper and lower support members 43a are nut members that are screwed into the bolts, and the pair of lead conductors 41b penetrates the upper support member 43a.

The above-mentioned structure of the bolt and the nut member corresponds to the concentrating position adjusting means. As a concentrating position adjusting means, a structure comprising a rack and a pawl lever may be adopted.

To heat the inner surface of the work 10 using the main coil 40, first, the work 10 is placed on the pedestal 50 and positioned and fixed. At this time, the coil 40 is above the work 10. When the setting of the work 10 is completed, the pedestal 50 is raised and the heating conductor 41a of the coil body 41 is inserted at a predetermined position inside the work 10. Then,
The outlet ring 42 is inserted inside both ends of the work 10. Then, a high frequency current is passed through the coil body 41. As a result, the inner surface layer of the work 10 is heated by high frequency.

At this time, since the outlet rings 42 are present above and below the heating conductor 41a, it is possible to prevent the magnetic flux from being generated vertically from the heating conductor 41a. Therefore, the heating range is prevented from reaching the boundary with the cutout portion 12.

When the connecting member 43b of the supporting means 43 is rotated, the upper supporting member 43a which does not rotate moves in the axial direction. The connecting member 43b is fixed, and the lower support member 43
When a is rotated, the support member 43a moves in the axial direction. As a result, the upper and lower outlet rings 42 independently move in the axial direction, and the heating range on the inner surfaces of both ends of the work 10 is finely adjusted.

[0024]

As described above, since the high frequency heating coil of the present invention is equipped with a pair of outlet rings,
It is possible to prevent the heating range from expanding to the inner surfaces of both ends of the work. Since the outlet ring is connected to the coil body, it is not necessary to attach or detach the outlet ring to or from the work, and the heating work can be efficiently performed with the same labor as when the outlet ring is not used. Since the insertion position of the outlet ring can be set regardless of the end shape of the work, the effect of suppressing the heating range is also high. Moreover, in the case where the concentrating position adjusting means is provided, the interval between the concentrating rings can be changed, so that the heating range of the inner surface of the work can be finely adjusted.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a high frequency heating coil showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a vertical sectional view showing a conventional high-frequency heating coil and a method of using the same.

[Explanation of symbols]

 10 Work 11 U Groove 12 Notch 40, 20 High Frequency Heating Coil 41 Coil Main Body 41a Heating Conductor 41b Lead Conductor 42, 30 Outlet Ring 43 Support Means 43a Supporting Member 43b Connecting Shaft 50 Cradle

Claims (3)

[Claims] 1. A high frequency heating coil for high frequency heating an inner surface of a cylindrical work for quenching the inner surface, the circular heating conductor being concentrically inserted on the inner surface of the work and facing the inner surface. A coil body having lead conductors extending from the heating conductor in the axial direction of the heating conductor to energize the heating conductor, and an axis of the heating conductor to prevent magnetic flux from spreading to both ends in the axial direction of the heating conductor. A pair of concentrator rings arranged on both ends in the direction and a pair of support members that respectively support the pair of concentrator rings from inside are coupled by a coupling member, and at least one of the pair of support members and the coupling member is coupled to the coil body. High-frequency heating coil, comprising: 2. The high frequency heating coil according to claim 1, further comprising a concentrating position adjusting means for moving the pair of supporting members in the axial direction with respect to the connecting member. 3. The concentrating means for adjusting the position of the outlet ring, wherein the connecting member of the ring supporting means is a bolt located at the axial center of the heating conductor, and the bolt is rotatably connected to the lead conductor of the coil body. The high frequency heating coil according to claim 2, wherein the pair of support members are nut members screwed to the bolts, and the lead conductor is passed through one of the support members.