JP2002018524A - Deformation straightening apparatus of annular member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deformation straightening apparatus capable of precisely straightening a deformation in a short time while suppressing a hardness variance due to a heating fluctuation in straightening a deformation. SOLUTION: In the state an outer diameter face of an annular member 1 is restricted by a setting die 2, the annular member 1 is heated to a desired tempering temperature and subjected to deformation straightening. A heating means consists of a magnetic body ring 10 forming an endless magnetic path piercing the space in a center part of the annular member 1 in the axial direction, a coil 3 coiled to part of the magnetic body ring 10 and an electric current supply apparatus 11 supplying AC to the coil 3. Further, the annular member 1 is induction-heated by eddy current caused by induction change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for correcting deformation of an annular member such as a raceway or a gear of a rolling bearing due to heat treatment using a correction mold.

[0002]

2. Description of the Related Art As a technique for correcting deformation of an annular member while performing tempering in a short time, there is a technique described in, for example, International Publication No. WO96 / 06194.
This technique uses an annular member 1 to be corrected, as shown in FIG.
Is restrained by a donut-shaped straightening mold 2, and the restrained annular member 1 (hereinafter, also referred to as a workpiece) is directly induction-heated through a coil 3 arranged near an end face of the annular member 1. By using the increase in the restraining force by the correction mold 2 due to the thermal expansion of the annular member 1 due to the heating and the transformation plasticity appearing in the tempering process, the circular member 1 is corrected for roundness deformation, inclination deformation, and the like. Is what you do.

[0003]

However, in the above-described conventional deformation correction technique, induction heating is employed as a heating means. In the induction heating, heating is performed by a distance from the coil 3 (mainly a distance in the axial direction S). There may be a difference in temperature. For this reason, there has been a problem that even with the annular member 1 having a large thickness and a large width, it is difficult to obtain uniform hardness due to uneven heating even if the deformation is corrected. In particular, when heating a plurality of annular members 1 at a time,
There is a problem that it is difficult to correct a plurality of annular members 1 at a time because the hardness tends to vary greatly between the annular members 1.

[0004] The high-frequency induction coil 3 used for the induction heating generally has an electromagnetic design point of view.
As shown in FIG. 6 which is a plan view, in many cases, the C-shape is set to one turn (the number of turns is less than one turn), and the one-turn high-frequency induction coil 3 serves as a power supply unit due to its structure. It is inevitable that a gap 4 exists between the two bent portions 3a.

[0005] When induction heating is performed using the one-turn high-frequency coil 3 as described above, considering the heating state of the work 1 along the circumferential direction, the bent portion 3a of the coil 3 is considered.
Unlike other work parts, the work part located in the periphery (in the vicinity of the range of the angle θ in FIG. 6) is not heated by induction because a uniform eddy current is not generated. That is, since the magnetic flux density applied to the work 1 is different between the periphery of the bent portion 3a of the coil 3 and the other portions, uneven heating occurs in the circumferential direction of the work 1. Also from this result, there is a possibility that unevenness in the circumferential direction is formed on the corrected annular member 1, that is, the product.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a deformation correcting apparatus capable of correcting deformation with high accuracy in a short time while suppressing unevenness in hardness due to uneven heating during deformation correction. The challenge is to provide

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a state in which at least one of an outer diameter surface and an end surface of a cylindrical member or an annular member after quenching and hardening is restrained by a straightening mold. In a deformation correcting apparatus for correcting the deformation by heating the annular member to a desired temper temperature by a heating means, the heating means may extend through a space in a central portion of the annular member in the axial direction and have an endless magnetic shape. An annular magnetic body capable of forming a path, a primary coil wound around a part of the magnetic body, and a current supply device for supplying a primary alternating current to the primary coil, and the annular member is formed by induced electromotive force. To provide a deformation correcting apparatus characterized by induction heating. [Action] Regarding the work heating principle in the present invention,
This will be described with reference to FIG.

When a current I1 flows through the primary coil 10,
A magnetic flux φ penetrating through the coil 10 is generated in the annular magnetic body 11. The magnetic flux φ also penetrates the secondary coil 12 to generate a current I2 in the secondary coil 12 and generate an induced electromotive force ε2. That is, when a current flows through the primary coil 12, an induced electromotive force ε2 is generated in the secondary coil 12. The inventor has conducted intensive studies to apply this principle to the field of heat treatment, and has come up with the present invention.

That is, if the secondary coil 12 in FIG. 4 is replaced by an annular member, and the annular member is restrained by the correction mold, and an alternating current is passed through the primary coil 10, the secondary coil 12 is induced into the annular magnetic body 11. Simultaneously with the generation of the magnetic field, a secondary eddy current is generated in the annular member, and the annular member is induction-heated. Thus, tempering is performed in a state in which the outer diameter surface of the annular member that is about to undergo thermal expansion is constrained by the correction mold, and the circular member has a roundness and a tilt deformation without generating uneven heating. Be corrected.

[0010] Since the main heating is performed by induction heating through a magnetic path (annular magnetic body) penetrating the center of the annular member in the axial direction, uneven heating due to the axial thickness of the annular member is prevented. In addition, the induction heating can be performed uniformly even when viewed along the circumferential direction of the annular member. . Here, the present applicant has previously addressed the above-mentioned problem of causing uneven heating, as disclosed in Japanese Patent Application Nos. 11-242004 and 2000-43.
No. 12 discloses a heating means.

The invention disclosed in Japanese Patent Application No. 11-242004 suppresses uneven heating in the circumferential direction by devising a correction mold while adopting the above-described conventional apparatus configuration (see FIGS. 5 and 6). Things. In addition, as shown in FIG. 7, the invention of Japanese Patent Application No. 2000-4312 sandwiches the annular member 1 in the width direction S between a pair of heating cores 7 and 8 and heats the annular member 1 using heat generated by magnetic hysteresis loss. Is performed to suppress uneven heating in the circumferential direction and the axial direction. This heating device is capable of ascending and descending with respect to the lower core portion 8a and the upper core portion 7a (the lower core portion 8a) which are opposite ends of the C-shaped core formed by laminating silicon steel plates and which face each other with the annular member 1 interposed therebetween. And the cores 7a and 8a are provided with coils 3 surrounding each other, and the work 1 is heated by supplying an alternating current to the coils 3 to generate a high-density alternating magnetic flux in the core. The heat is generated by utilizing the heat generated by the magnetic hysteresis loss caused by the high-speed reversal of the direction of the magnetic flux in the work 1 held between the core portions 7a and 8a.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a deformation correction device according to the present embodiment. The deformation correction device of the present embodiment includes a correction mold 2 that restrains a work 1 and a heating unit that heats the work 1 by magnetic induction heating.

The heating means includes an annular magnetic body (hereinafter, referred to as a magnetic ring 10), an electromagnetic induction coil 3 wound around a part of the magnetic ring 10, and a primary alternating current applied to the electromagnetic induction coil 3. And an AC current supply device 11 for supplying the current. The magnetic ring 10 includes a U-shaped core (hereinafter referred to as a main core 12) having an open upper side, and a rod-shaped upper core connecting between both ends of the left and right feet 12 a and 12 b of the main core 12. The main core 12 and the upper core 13 are both formed by bundling silicon steel plates. As a result, the magnetic ring 10 of the present embodiment forms a square magnetic path. The upper core 13 is detachable from the main core 12.

In the present embodiment, the cross-sectional shape of the magnetic ring 10 may be a dimension as close as possible so as not to contact the inner diameter surface of the work 1, for example, a square of 40 mm × 40 mm. However, the cross-sectional shape of the core can be changed as appropriate, such as a cross shape or a circle. An electromagnetic induction coil 3 constituting a primary coil is wound around one of the left and right feet 12a and 12b of the main core 12. However, the electromagnetic induction coil 3 is installed such that the magnetic flux generated from the coil does not directly affect the work 1. In addition, the coil 3 which is feeding
The coil 3 is provided with a cooling device (not shown) for cooling with a refrigerant such as water or air in order to suppress heat generation of the coil 3.

The electromagnetic induction coil 3 is connected to the AC current supply device 11 so that AC current can be supplied from the AC current supply device 11 to the electromagnetic induction coil 3. The work 1 and the correction mold 2 can be inserted from above into the other 12b of the left and right feet 12a and 12b of the main core 12, and the main core 1
The two feet 12b are arranged so as to pass through the center of the work 1 in the axial direction S. In addition, a support base 14 for mounting (supporting) the work 1 and the correction mold 2 loaded on the foot 12b is provided in the vicinity of the foot 12b. The mold 2 is positioned.

Thus, by supplying an alternating current to the electromagnetic induction coil 3, the magnetic ring 1 made of a laminated steel plate is supplied.
0, a high-density alternating magnetic flux is generated, and then the other foot 12b of the main core 12 is placed in the center of the work 1
A secondary current (eddy current) is generated therein, and the work 1 is induction-heated. The correction mold 2 has an annular shape, and the inner diameter is set slightly larger than the outer diameter of the work 1. The correction mold 2 is made of a non-magnetic material,
It is not heated together with the work 1. Examples of the non-magnetic material forming the correction mold 2 include a non-magnetic metal such as a titanium alloy and austenitic stainless steel, and a ceramic such as alumina and zirconia.
In particular, from the viewpoint of accurately constraining the work 1, ceramics having high hardness, such as silicon nitride, are preferable. The correction mold 2 is positioned so as to surround a part of the main core 12, and the central axis of the inner diameter is the same as that of the core.

The upper and lower corners of the inner diameter surface of the straightening die 2 (the surface that restricts the outer diameter surface of the work 1) are chamfered along the entire circumference as shown in FIG.
The work 1 can be easily charged and discharged into the correction mold 2. This means that when the work 1 is completely loaded into the straightening die 2, the width of the inner diameter surface of the straightening die 2 that is in contact with the outer diameter surface of the work 1
(Inner diameter surface width W2) becomes smaller than correction mold width W1.
However, the inner diameter surface width W2 is designed so that most of the outer diameter surface of the work 1 is in contact with the inner diameter surface of the correction mold 2 during the heating of the work 1. Further, as shown in FIG. 2, the width W1 of the correction mold 2 is designed to be smaller than the width W3 of the work 1. This prevents the correction mold 2 from hindering the operation when the work 1 is sandwiched between the upper and lower heating core portions.

As described above, the dimension of the correction mold 2 is such that the correction mold width W1 is smaller than the width W3 of the work 1 and the work 1
Is preferably smaller than the inner surface width W2 of the correction mold 2. By doing so, the end face and the chamfer portion of the work 1 are removed from the correction mold 2, so that the temperature of the work 1 can be easily monitored by the radiation thermometer. When a plurality of works 1 are to be processed simultaneously, it is sufficient to determine the inner surface width so that the outer surfaces of all the works 1 are in contact with the inner surface of the correction mold 2. It is preferable that the end face and the chamfer portion of the work 1 be seen from the correction mold 2.

Next, the operation of the straightening device will be described. First, the upper core 13 is separated from the main core 12 so that the work 1 can be loaded into the foot 12b. Next, the correction mold 2 and the work 1 are inserted into the foot 12b from above, and the correction mold 2 and the work 1 are placed on the support base 14. At this time, the support 14
The center of the work 1 is centered on the foot 12b, that is, the magnetic path is in the axial direction S.
The correction mold 2 is supported in a state where it is positioned in the lateral direction so as to penetrate (vertically). In addition, main core 1
It is good also as a structure which raises and lowers two sides.

At this time, the maximum outer diameter of the work 1 is
When the work 1 can be fitted into the correction mold 2 such that the work 1 is larger than the inner diameter of the correction mold 2, the work 1 is placed on the support 14 in a state of being integrated with the correction mold 2. Also, the work 1 has a maximum outer diameter smaller than the inner diameter of the straightening mold 2.
If the correction mold 2 is not fitted to the correction mold 2, the work 1 is loaded into the correction mold 2 after the correction mold 2 is first placed on the support base 14 and positioned.

Here, the inner diameter of the correction mold 2 is designed to be slightly larger than the outer diameter of the work 1 such as [the outer diameter of the work 1 × 1.001]. Correction mold 2 smaller than inner diameter. However, the work 1 has a slightly elliptical shape due to the deformation during the heat treatment in the previous process, and the large-diameter side is the correction mold 2.
It may be larger than the inner diameter.
Can be fitted into the correction mold 2.

Next, the upper core 13 is connected to both legs 12a, 12b of the main core 12 by the upper core 13.
Is installed, and the upper core 13 and the main core 12 constitute a magnetic closed circuit. When an alternating current is applied to the electromagnetic induction coil 3 in this state, a high-density alternating magnetic flux is generated in the laminated steel sheet constituting the magnetic ring 10, and then coaxially surrounds the feet 12 a and 12 b of the main core 12. A secondary current is generated in the work 1 placed in the work 1, and the work 1 is induction-heated by the secondary current.

Although the work 1 tends to thermally expand by heating, the work 1 is constrained by the correction mold 2 and the roundness deformation and the inclination deformation are corrected by the transformation plasticity appearing in the tempering process.
At this time, since the correction mold 2 is formed of a non-magnetic material, the correction mold 2 is not affected by magnetic heating, that is, expansion due to magnetic heating is suppressed, and a desired correction effect is secured.

Further, the alternating magnetic flux penetrates the center of the work 1 in the axial direction and is heated by the eddy current due to the periodic reversal of the induced electromotive force, so that the work 1 is uniformly heated over the entire circumference. Not only that, the workpiece 1 is also uniformly heated in the axial direction S irrespective of the thickness of the work 1, thereby suppressing the occurrence of uneven heating. As a result, unevenness in hardness of the work 1 after the correction is reduced.

This means that the width of the correction mold 2 is increased,
Even if a plurality of works 1 can be loaded in the straightening mold 2 in a stacked state, and a plurality of works 1 are corrected at one time,
When the magnetic flux penetrates all the works 1 in the correction mold 2, all the works 1 are heated by the eddy current due to the periodic reversal of the same amount of the induced electromotive force. In other words, a plurality of works 1 are processed by a single deformation correction process.
It is also possible to correct the roundness deformation and the inclination deformation at the same time while suppressing the unevenness in hardness between them to a low level.

Here, the magnetic path formed by the magnetic ring 10 is:
It is not necessary to be rectangular, and any shape may be used as long as the portion penetrating the center of the work 1 extends along the axial direction S. Here, even in the apparatus according to the present invention, as described above, similarly to the related art, an increase in the restraining force with the correction mold 2 due to the thermal expansion of the heated work 1;
Due to the tempering effect, the roundness deformation and the tilt deformation are corrected.

However, the above conventional example or Japanese Patent Application No.
In the invention described in Japanese Patent No. 242004 (see FIG. 5), heating is performed based on the simple induction heating principle, and in the invention described in Japanese Patent Application No. 2000-4312 (see FIG. 7), heating is performed based on the hysteresis loss principle. , Completely different from these. Therefore, the operation of the apparatus, the hardness distribution (product quality) inside the processed work 1 and the heating rate are also different.

For this reason, by devising the gap between the foot portion 12b of the main core 12 and the work 1, and the sectional shape of the foot portion 12b, it is possible to perform the correction more accurately.

[0029]

Next, Table 1 shows the results of the deformation correction of the examples based on the above embodiment. For comparison, the above-described deformation correcting device of the conventional example (however, Japanese Patent Application No. Hei 11-242).
No. 004 is not adopted) (see FIG. 5), and correction is performed by a deformation correction device having a heating unevenness countermeasure based on the invention described in Japanese Patent Application No. 2000-4312 (see FIG. 5). 7) are also shown as Comparative Example A and Comparative Example B, respectively.

Here, the maximum outer diameter of the work 1 is 60.0 mm
φ, and the thickness and width of each are as shown in Table 1.
Hardened and tempered. In addition, even if any work 1 is to be straightened, the outer diameter of the straightening mold 2 should be 150 mmφ.
The inner diameter was set to [the outer diameter of the work 1 × 1.001]. The heating pattern of the work 1 is simple heating in which the work temperature shows a linear increase with respect to the heating time, and the work temperature at the end point is referred to as the highest attained temperature. The maximum attained temperature in the straightening process is 35
0 ° C. The power supplied to the coil 3 of each device is set to be the same.

The hardness unevenness in Table 1 refers to a variation in hardness in a cross section of the same work 1.

[0032]

[Table 1]

As can be seen from Table 1, the effect of correcting the roundness and the inclination by the deformation correcting apparatus according to the present invention is comparable to or slightly improved from the results of Comparative Examples A and B, and is equal to the conventional one. It can be seen that the correction effect can be obtained. Conversely, the effect of correcting the roundness and the inclination is slightly worse in Comparative Example A as the thickness increases, but in this example,
Even if the wall thickness is increased, the correction effect is equal or slightly better (see c of the work), and the same correction effect is ensured even if the width is increased.

Focusing on the unevenness in hardness, in Comparative Example A, the hardness unevenness was as large as about 30 Hv in any of the works 1, whereas the hardness unevenness in the example was 9 Hv, as in Comparative Example B. It can be seen that the hardness is significantly smaller before and after, and that unevenness in hardness can be significantly reduced. That is, by using the device according to the present invention, it is possible to suppress unevenness in hardness to a level sufficient for practical use.

Further, focusing on the heating time required for the correction, the heating time of the comparative example B is significantly longer than that of the comparative example A, but in the example, the unevenness of the hardness is as low as the comparative example B. Comparative example A
It can be as close as possible. Here, FIG. 3 shows the relationship between the heating time and the work temperature in each device. The difference in the heating rate is such that the apparatus used in Comparative Example A heats at a high frequency with a high frequency, so that the heating rate is fast.
This is because the heating speed is slow due to heating due to magnetic hysteresis loss. On the other hand, in the device of the embodiment according to the present invention, the temperature rising speed can be increased by adjusting the frequency and voltage of the electromagnetic induction.

As described above, by using the present invention, even when correcting the deformation of the work 1 having a large thickness or a large width, the heating time close to the conventional example, that is, the time required for the correction is reduced by the conventional apparatus. , Deformation correction can be performed with high accuracy, and unevenness in hardness after deformation can be significantly reduced. In particular, it can be seen that the present invention has a special effect as a deformation correcting means for correcting the annular member 1 having a large thickness or a large width or a plurality of annular members 1 at a time.

The apparatus used in the comparative examples A and B and the apparatus according to the present invention may be properly used depending on the size of the work 1. For example, if the work 1 is thin and has a small width, the unevenness of hardness can be reduced and the heating time can be shortened. Therefore, the apparatus of Comparative Example A may be used. But it is good.

[0038]

As described above, by adopting the present invention, deformation such as roundness or inclination generated after heat treatment can be suppressed while minimizing unevenness in hardness caused by uneven heating of the annular member. There is an effect that correction can be performed in a short time and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram (when a work is loaded) illustrating a deformation correction device according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view showing an inner diameter side of a correction mold according to a third embodiment based on the present invention.

FIG. 3 is a diagram showing a relationship between a heating rate and a work temperature in an example.

FIG. 4 is a principle diagram of a magnetic circuit showing a heating principle of the present invention.

FIG. 5 is a schematic view illustrating a conventional deformation correction device.

FIG. 6 is a plan view for explaining a conventional problem.

FIG. 7 is a schematic diagram illustrating an example of magnetic heating.

[Explanation of symbols]

 Reference Signs List 1 annular member (work) 1a outer diameter surface 2 correction mold 2a inner diameter surface 2b corner 3 coil (primary coil) 3a bent portion 4 gap 7 upper heating core 8 lower heating core 10 magnetic ring (annular) Magnetic material) 11 AC current supply device 12 Main core 13 Upper core 14 Support base S Axial direction

Claims (1)

[Claims] 1. Heating the annular member to a desired temper temperature by a heating means in a state where at least one of the outer diameter surface and the end surface of the annular member such as a cylindrical shape or an annular shape after quenching and hardening is restrained by a straightening mold. A deformation correcting device for correcting deformation by heating, wherein the heating means includes an annular magnetic body capable of axially penetrating a space in a central portion of the annular member and forming an endless magnetic path; An apparatus for correcting deformation of an annular member, comprising: a primary coil wound around a portion; and a current supply device for supplying a primary alternating current to the primary coil, wherein the annular member is induction-heated by an induced electromotive force.