JP2006179359A - Induction heating coil and induction heating method for heating annular member from inner and outer periphery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating coil and an induction heating method capable of heating an annular member from inner and outer peripheries thereof to a deep part thereof. <P>SOLUTION: This induction heating coil is so structured that leg parts of two U-shaped conductors 1 and 2 are arranged by straddling a heating part at predetermined distances from the inner and outer peripheral surfaces of an annular member W to be heated; one-side leg ends of the two U-shaped conductors 1 and 2 are connected to each other; and a power source is connected to the other-side ends thereof to form a coil. The heating speed is increased and heat is equalized by heating the workpiece W from the inner and outer peripheries while turning it by arranging the two inducting heating coils 10 and 10' in the circumference of the workpiece W. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an induction heating coil and an induction heating method for heating an annular member from the inner and outer circumferences by heating the annular member simultaneously from the inner and outer circumferences by induction heating. It is used for quenching bearing steel of bearing race material.

The heating of the annular member by induction heating is widely used. However, induction heating is preferable for surface heating such as surface quenching or heating quenching of thin members, but it has been difficult to heat the entire thick member to a deep portion.
Therefore, conventionally, when an annular member such as quenching of bearing steel of a race material of a large bearing is heated to a deep portion, atmospheric furnace heating or the like has been mainly used.

  However, large-scale equipment such as an atmospheric furnace has a problem that the equipment cost is high, the heat treatment time is long, and it is difficult to produce a small variety of products.

  Therefore, an object of the present invention is to solve the above problems and provide an induction heating coil and an induction heating method capable of heating to a deep portion of an annular member by induction heating.

  In order to achieve the above object, the induction heating coil for heating the annular member of the present invention from the inner and outer periphery has a predetermined interval between the foot portions of the two U-shaped conductors and the inner and outer peripheral surfaces of the heated annular member. The coil is formed by arranging the two U-shaped conductors so that the one leg ends are connected to each other and a power source is connected to the other leg ends. It is what.

  The connecting end of the foot portions of the two U-shaped conductors and the connecting end of the power source may be on the inner or outer periphery of the annular member to be heated, but it is easier to place the power connecting end on the outer peripheral side. It is.

  As described above, the induction heating coil of the present invention has two U-shaped conductors arranged across the inner and outer circumferences of the heated annular member, and the inner and outer two U-shaped conductors are used to connect the annular member to the inside and outside. Since it heats simultaneously, it can heat to the deep part of an annular member efficiently and rapidly.

It is desirable that at least the U-shaped conductor of the induction heating coil is formed by cutting out the conductive material of the integral block. Conventional induction heating coils are formed by bending a metal tube or welding or brazing a metal plate. However, in the case of a coil having a complicated shape, the coil manufactured by such a method has a problem in durability. Therefore, the present invention has been able to increase the coil life by more than three times as compared with the conventional one by cutting out from a single block material.

An induction heating method for heating an annular member of the present invention from the inner and outer circumferences is provided by arranging two or more induction heating coils according to claim 1 or 2 on the circumference of the annular member to be heated. The member is heated while rotating.
By doing so, two or more portions of the annular member are heated at the same time, so that more rapid soaking is possible. Although two or more induction heating coils may be arranged at an angle to the circumference, two heating coils should be arranged symmetrically on the diagonal of the circumference for efficiency and simplicity of structure. Is desirable.

  The induction heating method for heating the annular member of the present invention from the inner and outer circumferences includes arranging two coils of the induction heating coil according to claim 1 or 2 on the circumference of the heated annular member, The distance between the inner peripheral side foot conductor and the inner peripheral surface is made larger than the distance between the outer peripheral foot conductor and the outer peripheral surface, and the other inner side foot conductor and inner peripheral surface of the heating coil Is set to be smaller than the distance between the outer leg conductor and the outer peripheral surface, and the heated annular member is heated while rotating.

  If it carries out like this, the heating amount of an outer periphery will increase more than an inner periphery in one coil, and the heating amount of an inner periphery will increase from an outer periphery in the other coil, and both will supplement and it will be easy to heat to uniform temperature. In addition, since the heating area of the inner circumference is smaller than the heating area of the outer circumference, as a whole, it is uniform that the distance between the axial conductor and the inner circumferential surface is wider than that between the outer circumferential face and the heating amount of the outer circumferential face is increased. Desirable to increase temperature.

  The induction heating coil and the heating method are highly effective when used for heating an annular member such as quenching of bearing steel of a race material for a large bearing.

  The two coils or two or more induction heating coils can be connected in series or in parallel to a single power source or a plurality of power sources.

  According to the induction heating coil and the induction heating method of the annular member of the present invention, heating up to the deep part of the annular member, which was difficult without conventional furnace heating, is possible by induction heating, so a large facility is unnecessary, The heat treatment time is shortened and the heat treatment cost is reduced. Further, even if the diameter of the annular member changes, the heating coil can be used for both large and small diameters as long as there is no large variation in the wall thickness. In addition, the factory environment is improved over heat treatment by furnace heating. Further, by cutting the coil from the block material and making it, the life of the coil is increased and the heat treatment cost is reduced. The induction heating coil and induction heating method for the annular member of the present invention are particularly effective for quenching the bearing steel of the race material of the large bearing.

  Hereinafter, the induction heating coil and the heating method of the annular member of the present invention will be specifically described with reference to the illustrated embodiments. FIG. 1 is a diagram showing a configuration in which two induction heating coils of an annular member of the present invention are arranged, and FIG. 2 is a diagram showing an example of a coil formed by shaving from a block.

  First, the induction heating coil will be described with reference to FIG. In the induction heating coil 10, two U-shaped conductors 1 and 2 have foot conductors 1b, 1d and 2b, 2d in parallel, respectively, one end 1e of one foot conductor 1d and one end 2e of a foot conductor 2d. Are connected by a conductor 3, and leads 4 and 5 are connected to one end 1a of the other foot conductor 1b and one end 2a of the foot conductor 2b to form a coil. Thereby, the electric current added to the heating coil 10 flows with the lead part 4-U-shaped conductor 1-conductor 3-U-shaped conductor 2-lead part 5, and forms a coil current. An induction heating coil 10 is disposed across the U-shaped conductors 1 and 2 across a heating portion of a to-be-quenched annular member (hereinafter referred to as a workpiece) W. In FIG. 1, the lead portions 4 and 5 are set on the outer periphery, but the lead portions may be disposed on the inner periphery.

  The distance between the insides of the foot conductors 1b and 1d and the insides of 2b and 2d of the U-shaped conductors 1 and 2 is that the U-shaped conductors 1 and 2 are heated by an annular member (hereinafter referred to as a workpiece) W to be hardened. When it is arranged across the part, it is dimensioned to have a predetermined gap between the inner and outer peripheral surfaces of the workpiece W. The lengths of the foot conductors 1b, 1d and 2b, 2d are set to correspond to the length of the heating surface in the axial direction of the workpiece W.

  An example of the induction heating coil 10 is formed by cutting a rectangular conductive material block as shown in FIG. The lead portions 4 and 5 may be cut out from the integrated block, but the lead portions may be bonded together by brazing or welding. Although not shown in the figure, the conductor is internally cooled by water holes. Thus, by cutting out the coil conductor from the block, it was possible to extend the life by three times or more as compared with a coil formed from a conventional tube material or plate material.

  Next, an induction heating method for the annular member of the present invention having the above configuration will be described with reference to FIG. Two heating coils 10 and 10 ′ having the same shape are disposed at symmetrical positions on the diagonal line of the workpiece W. The heating coils 10 and 10 ′ on both sides are arranged so that the U-shaped conductors 1 and 2 straddle the heating surface of the workpiece W. At this time, for example, the distance between the legs 1b and 2b of the U-shaped conductors 1 and 2 of the left heating coil 10 in the drawing and the outer peripheral surface of the workpiece W is the distance between the feet 1d and 2d and the inner peripheral surface of the workpiece W. The distance between the foot portions 1b 'and 2b' of the U-shaped conductors' 1 and 2 'of the heating coil 10' on the right side of the drawing and the outer peripheral surface of the work W is made slightly larger. It is set to be slightly narrower than the distance from the inner peripheral surface of W. As a result, the heating amount on the inner periphery of the left heating coil 10 is larger than that on the outer periphery, and the heating amount on the outer periphery of the right heating coil 10 'is greater than that on the inner periphery. The temperature of the workpiece W can be increased.

  Here, the work W is rotated by a rotation driving means (not shown), and the work W is heated by turning on the heating coils 10 and 10 ′ while rotating the work W.

  The two coils of the heating coils 10, 10 ′ may be connected to a single power source, or may be connected in series or in parallel from one power source.

  As described above, according to the heating coil and induction heating method of the annular member of the present invention, the foot conductor of the U-shaped conductor is disposed across the inner and outer circumferences of the annular member, and can be heated simultaneously from inside and outside. Therefore, it can heat to the deep part of a ring to be heated efficiently and rapidly.

  In addition, since the induction heating coil of the present invention is formed by shaving at least the coil portion from the conductive material of the integral block, the life is improved by three times or more as compared with the conventional coil.

  In addition, two induction heating coils are arranged on the circumference of the annular member to be heated, and two portions of the annular member are simultaneously heated and hardened, so that it is difficult to use alloy steel, etc. It became possible to heat an annular member to a deep part by induction heating.

  As described above, the heating coil and induction heating method of the annular member of the present invention can significantly reduce the heating time as compared with the conventional furnace heating, so that the heat treatment cost can be greatly reduced. In addition, since the heating coil of the present invention can be used even if the diameter of the annular member changes, the production of a small quantity and a variety of products becomes easier than in the case of furnace heating, and the in-process can be reduced. At the same time, the factory environment has been improved, reducing the cost of heat treatment and contributing to industrial development.

It is a figure explaining the induction heating method of the annular member of the embodiment of the present invention. It is a figure which shows an example of the induction heating coil shape | molded by shaving from the block body of this invention embodiment.

Explanation of symbols

1, 2, U-shaped conductor, 3 conductor, 4, 5 Lead part, 10 Induction heating coil, W work (hardened annular member)

Claims (7)

In the induction heating of the annular member, the foot portions of the two U-shaped conductors are disposed across the heating portion with a predetermined interval between the inner and outer peripheral surfaces of the heated annular member, and the two An induction heating coil for an annular member for heating an annular member from the inner and outer circumferences, wherein a coil is formed by connecting one foot end portion of a U-shaped conductor and connecting a power source to the other foot end portion. 2. The induction heating coil for heating an annular member according to claim 1, wherein at least the U-shaped conductor of the induction heating coil is formed by cutting from a conductive material of an integral block. The induction heating coil for heating an annular member according to claim 1 or 2, wherein the annular member to be heated is a bearing race member, and the entire race member is heated uniformly. The induction heating coil according to claim 1 or 2, wherein two or more coils are arranged on the circumference of the heated annular member and heated while rotating the heated annular member. Induction heating method to heat. Two coils of the induction heating coil according to claim 1 or 2 are arranged on the circumference of the annular member to be heated, and an interval between the foot conductor on the inner peripheral side of the one heating coil and the inner peripheral surface is set on the outer peripheral side. The distance between the foot conductor and the outer peripheral surface is larger than the distance between the foot conductor on the inner peripheral side of the other heating coil and the inner peripheral surface, and smaller than the distance between the foot conductor on the outer peripheral side and the outer peripheral surface. An induction heating method for heating the annular member from the inner and outer periphery, wherein the annular member to be heated is heated while rotating. 6. The induction heating method for heating an annular member according to claim 4 or 5, wherein the annular member to be heated is a bearing race member, and the entire race member is uniformly heated. 6. The annular member according to claim 4 or 5, wherein the two or more induction heating coils are connected in series or in parallel to a single power source or a plurality of power sources. Induction heating method.

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