JPS60141827A - High-frequency induction heating method - Google Patents

Abstract

PURPOSE:To enable uniform and simultaneous heating of plural raceway grooves with good working efficiency by disposing torus high-frequency induction heating coils into the respective plural raceway grooves provided on the inside circumferential surface of a cylindrical member with the eccentricity from the respective raceway grooves. CONSTITUTION:Torus high-frequency induction heating coils 4a, 4b of the same diameter connected in series to each other are used so as to meet the two raceway grooves 2, 3 formed on the inside circumferential surface 1a of a cylindrical member 1 fixed on a jig 12 and the outside size L1 thereof is made slightly smaller than the bore size L2 in the small diameter part 7 of said member 1. The above-mentioned coils 4a, 4b are first inserted into the respective chain line positions and thereafter the coils are horizontally moved in an arrow B direction and are disposed in the positions of the solid lines eccentric from the grooves 2, 3. High-frequency large current is then supplied to the coils 4a, 4b from a high- frequency power source 11 via leads 10 while the member 1 is rotated relatively with the coils 4a, 4b by the jig 12. After the circumferential surface parts of the grooves 2, 3 are thereby heated to a prescribed temp., the grooves are hardened by ejection cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of high-frequency induction heating a plurality of raceway grooves provided on the inner peripheral surface of a cylindrical member, for example, in a quenching process.

Conventionally, when performing the hardening treatment of the raceway grooves,
First, as shown in FIGS. 1 and 2, one of the two raceway grooves 2 and 3 provided on the inner peripheral surface 1a of the cylindrical member 1,
For example, a single-turn high-frequency induction heating coil (hereinafter simply referred to as a high-frequency coil) 4 is arranged so as to correspond to the raceway groove 2, and the cylindrical member 1 is induction-heated while rotating around its axis. Next, when a predetermined quenching temperature is reached, a coolant is injected to perform a quenching process, and then the cylindrical member 1 is turned upside down and the other raceway groove 3 is quenched. was. As described above, conventionally, the raceway grooves 2.3 in the cylindrical member 1 having a plurality of raceway grooves 2.
The heating and quenching treatment in step 3 is performed separately in multiple steps for each location.

In this case, of the inner circumferential surface 1a of the cylindrical member 1, the portions on both end face sides are made into large diameter portions 6, and the portion between these is made into small diameter portions 7. This is to ensure that the high frequency coil 4 inserted into the inner circumferential surface la is brought as close as possible to the raceway groove 2.degree. 3 so that high frequency induction heating can be performed efficiently. Therefore, when such a configuration is adopted, even if a plurality of single-turn high-frequency coils 4 are arranged according to the number of grooves and a plurality of raceway grooves are heated and hardened at the same time, the external dimension r of the high-frequency coil 4 , is the inner diameter dimension 1. of the small diameter portion 7 of the cylindrical member 1. , it is impossible to insert a plurality of high-frequency coils 4 into the cylindrical member 1 from the same direction and arrange them facing the raceway groove to be heat-treated.

As shown in FIG. 3, the outer dimension 7!1 of the high frequency coil 4 is equal to the inner diameter dimension I!1 of the cylindrical portion 10 and the small diameter portion 7. , it is possible to insert a plurality of high-frequency coils 4 into the cylindrical member 1 from the same direction and arrange them facing the raceway grooves 2.3, but in this case, as shown in FIG. In this case, the heated area (and thus the cured layer pattern) indicated by the symbol A becomes non-uniform.

As a result, on the inner circumferential surface of the cylindrical member 1, the side of the small diameter portion 7 is most deeply hardened, and the hardening gradually becomes shallower toward the side of the large diameter portion 6, resulting in a uniform hardened layer pattern. I can't.

For the reasons mentioned above, the reality is that conventionally, a plurality of raceway grooves are not heated and hardened at the same time.

However, in the conventional high-frequency induction heating method used in the hardening process, the raceway grooves 2.3 were individually heated one by one, which had the problem of extremely low work efficiency. . Also, is it possible to harden one raceway groove 2 and then apply the hardening treatment to the other raceway? When heating and hardening R3, when the raceway groove 3 was heated, the heat moved to the raceway groove 2 after quenching, and the groove 2 tended to be tempered. In this case, the shorter the distance between the raceway grooves 2.3, the more remarkable the above tendency becomes. If the required quenching hardness cannot be maintained, the raceway groove 2 which was first hardened will not be tempered.
This has the disadvantage that the quenching process must be immersed under water, resulting in very poor workability and a very unstable quenching process.

When the track a2.3 is heated and hardened individually, the hardening causes a difference in the amount of shrinkage deformation of the raceway grooves 2 and 3 between the valley grooves 2.3. That is, one raceway groove shrinks and deforms more greatly than the other raceway groove, and the l! The lL channel does not shrink or deform as much as the passage channel. Therefore, there was a problem that the dimensional accuracy of the cylindrical member 1 as a product was poor.

The present invention has been made by paying attention to the various problems mentioned above, and an object of the present invention is to solve the problems described above.
It is an object of the present invention to provide a high-frequency induction heating method that can uniformly heat a passage groove at the same time with good working efficiency.

The present invention is characterized in that, in a method of high-frequency induction heating a plurality of raceway grooves provided on the inner circumferential surface of a cylindrical member, each of the plurality of raceway grooves is provided with an annular high-frequency induction heating coil. and then moving the high frequency induction heating coil to a position eccentric to the raceway groove in order to bring some of the plurality of high frequency induction heating coils close to the raceway groove, and under this condition, The present invention is characterized in that the plurality of raceway grooves are simultaneously subjected to high-frequency induction heating while the cylindrical member and the high-frequency induction heating coil are relatively rotated.

Hereinafter, the present invention will be described in detail based on an embodiment shown in FIGS. 4 and 5. Note that in FIGS. 4 and 5, the same parts as in FIG. 1 are designated by the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, annular high-frequency induction heating coils (
4a and 4b (hereinafter simply referred to as high-frequency coils) are used. The spacing between these high frequency coils 4a, 4b is equal to the spacing between the raceway grooves 2, 3, and the external dimension L1 of the high frequency coils 4a, 4b is equal to the small diameter portion (minimum inner diameter portion) 7 of the cylindrical member 1. Inner diameter dimensions.

It is constructed slightly smaller than the .

Although not shown, a hollow water-cooled high-frequency coil 4
A and 4b are connected at one end to a cooling pipe and at the other end to a drain pipe in order to allow cooling water to flow inside. Moreover, these high frequency coils 4a and 4b have leads 10
is connected to a high frequency power source 11 via the high frequency power source 11, and a high frequency large current is supplied from the high frequency power source 11 to the high frequency coils 4a, 41].

Further, the above-mentioned high frequency coils 4a and 4b are configured to be moved in the horizontal direction in FIG. 4 by a moving means not shown.

Next, the high frequency induction heating method of the present invention will be described.

First, the cylindrical member l is placed on a part of the mounting jig 12 and fixedly supported. Next, the cylindrical member 1 and the mounting jig 12 are fixedly arranged at a predetermined position by a vertical lifting device (not shown) to form a high-frequency coil 4a.

It is moved upward toward the side of 4b. As a result, the high frequency coils 4a and 4b are inserted into the hollow portion of the cylindrical member 1. At this time, the outer dimension L1 of the high-frequency coils 4a and 4b is the inner diameter dimension 1 of the small diameter portion 7 of the cylindrical member 1. ．． 7, one of the high frequency coils 4b relatively passes through the small diameter portion 7, and the high frequency coils 4a and 4b pass through the cylindrical member 1 as shown by the two-dot chain line in FIG. The raceway grooves 2.3 are arranged in correspondence with each other.

Thereafter, the high-frequency coils 4a and 4b are moved horizontally by a moving device not shown, for example in the direction of arrow B in FIG. Placed. As a result, a portion of the high frequency coils 4a, 4b is disposed close to the raceway grooves 2, 3 in a biased state.

Under such conditions, the cylindrical member 1 is rotationally driven by a rotational drive device (not shown). Then, a high frequency large current (
As a result, the raceway grooves 2 and 3 of the cylindrical member I are simultaneously heated by high-frequency induction heating, and the peripheral surface portions of these grooves 2 and 3 are brought to the required hardening temperature. After the quenching temperature is reached in this manner, quenching is performed by commonly used injection cooling or the like.

When the above-described heating and hardening method is adopted, the circular portions of the raceway grooves 2 and 3 are uniformly heated and thus uniformly hardened. That is, the high frequency coil 4a.

When high-frequency induction heating is performed with coils 4b located at the positions indicated by the two-dot chain lines in FIG. 4, the high-frequency coils 4a, 4b, ! :itdomizo 2. Since the spacing between the grooves is relatively wide, the heating efficiency is poor, and the hardened layer pattern A does not have a uniform depth along the circumferential surface of the raceway grooves 2 and 3 as shown in FIG.

Furthermore, when the high-frequency coils 4a and 4b are placed in a horizontally moved position (eccentric position) as shown by the solid line in FIG. 4, high-frequency induction heating and After the cooling process, the heated area and thus the hardened layer pattern A becomes as shown in FIG. In this case, as is clear from FIG. 6, the hardened layer pattern 8a in the part of the raceway grooves 2 and 3 where the high-frequency coils 4a and 4h are closest is the deepest in the central part of each raceway groove 2.3. It becomes shallower as it moves away from each center. On the other hand, among the 1iJt grooves 2 and 3, the high frequency coil 4a.

In the hardened layer pattern 8b in the part where 4b is the farthest away, the side of the small diameter part 7 of the cylindrical member 1 is most deeply hardened,
It gradually becomes shallower toward the large diameter portion 6 side.

However, as in the case of this embodiment, the high frequency coil 4a.

If 4b is horizontally moved to an eccentric position as shown in Figures 4 and 5 and heated by rotation, efficient heating can be achieved by the high-frequency coil portion where the raceway grooves 2゜3 are close to each other. At the same time, uniform heating is achieved mainly in the high frequency coil portion by rotational heating. Therefore, uniform heating is performed along the entire circumferential surface of the raceway groove 2.3 as shown in FIG. 4, and as a result, the hardening pattern A of hardening depth can be efficiently obtained.

In addition, although the above-mentioned embodiment shows the case where the raceway groove has an arcuate cross section of 2°3, the present invention is not limited to this and can also be applied to a rectangular raceway groove such as a U-shaped cross section. The method is applicable.

7- According to the high-frequency induction heating method of the present invention as described in 1- below, the high-frequency induction heating coils disposed facing each other in a plurality of raceway grooves of a cylindrical member are eccentrically arranged relative to the raceway grooves, and one of the high-frequency induction heating coils is A portion of the raceway groove is disposed close to the raceway groove, and under this condition, the cylindrical member and the high-frequency induction heating coil are rotated relative to each other, and the plurality of raceway grooves are simultaneously subjected to high-frequency induction heating. It is no longer necessary to heat each raceway groove individually as in the above, and work efficiency can be greatly improved, and each raceway groove can be heated uniformly. Therefore, when hardening is performed after heating, each raceway groove can be cooled and hardened at the same time, so that a tempering phenomenon due to heat transfer does not occur. Moreover, there is no difference in the amount of shrinkage deformation between the raceway grooves due to individual quenching, and it is possible to efficiently obtain a cylindrical member in which a uniform quench-hardened layer with a small amount of deformation is formed.

[Brief explanation of drawings]

Figures 1 and 2 are for explaining the conventional high-frequency induction heating method. Figure 1 is a schematic cross-sectional view of the cylindrical member and high-frequency coil during heating, and Figure 2 is a schematic plan view of the same as above. 3 is a schematic cross-sectional view similar to FIG. 1 showing a state in which high-frequency coils are arranged correspondingly to eight raceway grooves of a cylindrical member, and FIGS. 4 and 5 are schematic sectional views of the present invention. Figure 4 is a schematic sectional view similar to Figure 1, Figure 5 is a schematic plan view similar to Figure 2, and Figure 6 is a diagram showing a cylindrical member. FIG. 2 is a schematic cross-sectional view similar to FIG. 1 showing a case where the high-frequency coil is not rotated relative to the high-frequency coil. 1... Cylindrical member, 2.3... Raceway groove, 4a, 4b... High frequency induction heating coil,
8a, 8b...Cured layer pattern, A...
... Heating area (cured layer pattern), L, ...
External dimensions of the high frequency induction heating coil, L2... Inner diameter dimension of the small diameter portion of the cylindrical member. Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] In a method of high-frequency induction heating a plurality of raceway grooves provided on the inner circumferential surface of a cylindrical member, an annular high-frequency induction heating coil is arranged correspondingly to each of the plurality of raceway grooves, and then a plurality of the high-frequency induction heating coils are arranged correspondingly to each of the plurality of raceway grooves. In order to bring a part of the heating coil close to the raceway groove, the high-frequency induction heating coil is relatively moved to a position eccentric to the raceway groove, and under this state, the cylindrical member and the high-frequency induction A high-frequency induction heating method, characterized in that the plurality of raceway grooves are simultaneously subjected to high-frequency induction heating while rotating the heating coil relatively to the heating coil.