JPH06200326A - Method for hardening bearing ring - Google Patents

Abstract

PURPOSE:To form a homogeneous hardened layer around the all periphery of a raceway surface in induction moving hardening at the time of subjecting moving hardening to a raceway surface of a large-diameter bearing ring of a bearing for a rotary seat or the like by compact induction heating coils. CONSTITUTION:Closely to a raceway surface 22, induction heating coils 51 and 52 with a pair of coolers 61 and 62 rotating in a relatively opposite direction around a bearing ring are arranged. Heating and rapid cooling are started from a position 92 at which both coils are approached, moving hardening is executed in a relatively opposite direction and the hardening is completed at a position at which both coils are again abutted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an induction surface hardening method for carrying out uniform surface hardening without forming a soft zone on the raceway surface of a large diameter bearing ring such as a bearing for a swivel seat.

[0002]

2. Description of the Related Art A conventional quenching method for a large-diameter bearing ring is such that a high-frequency induction heating coil is brought close to the inner or outer raceway of the bearing ring so that the coil and the bearing ring are relatively moved. Rotate and move continuously, induction heating of orbital groove by coil and water injection quenching from nozzle that follows coil,
The entire circumference of the bearing ring is hardened.

In this induction hardening, the hardening start portion of the raceway surface of the raceway groove is reheated and hardened by annealing at the end of quenching after one-turn quenching, so that the wear resistance is deteriorated. However, it sometimes causes quench cracks. Therefore, taking a bearing for a slewing seat having a sectional shape as shown in FIG. 4 as an example, in FIG. 5, when induction hardening is performed on the raceway surface 12 of the outer ring 1, induction heating quenching on the raceway surface is started. An unquenched portion 96 is left between the portion 91 and the end portion 92, and this portion becomes the soft zone 96, which causes a reduction in the life of the bearing, and therefore the bearing use is limited to low load applications. There was such a problem.

In the induction hardening method for a large diameter raceway ring without forming a soft zone on the raceway surface, large-capacity heating coils are arranged at a plurality of places in the raceway groove, and the raceway ring is rotated.
There is a method in which the entire circumference of the orbital surface is heated to a predetermined temperature at the same time, water is simultaneously poured onto the entire circumference, and quenching is performed. In this method, the entire circumference of the raceway surface is heated at once and cooled, so that the soft zone is not formed.

However, in this method, since the entire circumference of the raceway is heated at once, the supplied high frequency power becomes extremely large in a large raceway, which requires a high-frequency power oscillator with a large output. Not realistic.

The present invention is an induction hardening method in which a relatively small induction heating coil is relatively rotated along the circumferential surface of an orbital ring, and there is no soft zone on the orbital surface due to reheating of a soft zone or a quench hardening layer. It is an object of the present invention to provide a quenching method for forming a surface hardening layer that is substantially homogeneous.

[0007]

A method for quenching an orbital ring according to the present invention, in which a bearing ring of a large diameter bearing is attached to a support and a pair of induction heating coils with cooling means near the orbital surface of the orbital ring is provided around the orbital ring. The induction heating coils are placed so that they can move relative to each other, and heating and quenching are started from the positions of the orbital surfaces where the induction heating coils are brought close to each other. In this method, quenching is performed, and the heating and quenching of the raceway surface is terminated again at a raceway surface position where the pair of induction heating coils abut against each other.

According to the present invention, the above-mentioned pair of induction heating coils constitutes one set, and a plurality of sets of induction heating coils are arranged in the opposite directions to the other induction heating coils which are adjacent to each other around the orbital ring. Included is a quenching method arranged to rotate.

[0009]

Embodiments of the present invention will be described with reference to the drawings.

1 and 2 show the positional relationship between the inner ring 2 and the induction heating coils 51, 52 when the outer peripheral raceway surface 22 of the inner ring 2 of the ring is induction hardened.

A pair of induction heating coils 51 and 52 are arranged outside the inner ring 2 fixed to a support (not shown) so as to rotate in opposite directions to each other. Two
The two are closely spaced with a narrow gap. Each induction heating coil 51, 52 is provided with a cooler 61, 62 such as a water injection nozzle (not shown), and each induction heating coil 5
It follows the rotation of 1,52.

As shown in FIG. 1 (A), the hardening process is started by supplying high-frequency power with the pair of induction heating coils 51, 52 in close proximity to each other.
The surface area 91 of the orbital surface 22 approaching is heated and reaches a predetermined quenching temperature, and then a cooling agent such as water injection is injected onto the orbital surface 22 from the coolers 61 and 62 connected to the coils 51 and 52, respectively. Then quench. This first quenching site becomes the quenching start position 91.

Then, as shown in FIG. 1 (B), the induction heating coils 51, 52 are separated from each other and rotated in opposite directions to each other so as to rotate the induction heating coils 51, 52.
Heating and quenching by coolers 61 and 62 which are respectively connected to the coils 51 and 52 and follow each other,
The hardened layer 9 is successively formed.

After the induction heating coils 51 and 52, which are inverted with respect to each other, are brought close to each other again and abutted against each other, the surface region 92 on the guide surface 22 is heated and then provided separately as shown in FIG. A cooling agent such as water injection is sprayed from the cooler 63 to quench it and the quenching work is completed. At the final stage of quenching, as shown in FIG. 2 (B), when both coils collide and come close to each other, the high frequency power is stopped and the coils are immediately separated from each other to the left and right. 63 may be brought close to the heating region 92, water may be injected, and quenching may be performed. In this way, the surface region 92 of the raceway surface 22 that is finally quenched becomes the quenching end position 92.

As described above, the substantially uniform quenching layer 9 is formed on the entire circumference of the raceway surface 22 from the quenching start position 91 to the quenching end position 92. Further, in the method of the present invention, since the entire circumference of the raceway surface is quenched without reheating the already formed hardened layer 9, a soft portion due to reheating or unquenching is not formed on the raceway surface.

In the description of the above example, the quenching method of the inner ring 2 of the bearing ring was shown, but in the same manner, a pair of induction heating coils are provided around the inner periphery of the outer ring having the raceway surface 11 of the outer ring 1 (FIG. 4). By arranging, the outer ring 1 can be induction hardened.

In FIG. 3, two pairs of induction heating coils 51a, 52a and 51b, 52b are provided around the outer circumference of the inner ring 2.
An example in which the induction heating coils 51a, 52a and 51b, 52b are separated from each other with the quenching start positions 91, 91 shown in FIG. Then, when it is rotated only 1/4 turn, the quenching end positions 92, 9 that come into close proximity with the induction heating coils of the other set
At 2, the quenching process ends. In this way, when two sets of induction heating coils are used, the quenching treatment speed is about 4 times as compared with the conventional method using a single induction heating coil.
Doubled. Furthermore, by arranging several pairs of induction heating coils,
It is also possible to speed up the quenching process.

The above embodiment shows an example in which the bearing races are fixed and a pair of induction heating coils are rotated around the races in opposite directions to quench the raceway surface. Also included is a quenching method in which a bearing ring is rotatably mounted on a support and a pair of induction heating coils are rotated in opposite directions relative to the rotating bearing ring and relative to the bearing ring.

That is, the bearing ring may be attached to a rotatable support, one of the pair of induction heating coils may be fixed, and the other induction heating coil may be rotatably arranged around the bearing ring.
In this case, the bearing ring is rotated immediately after quenching at the quenching start position, and at the same time, the other induction heating coil is rotated in the direction of rotation of the bearing ring at a rotation speed of about twice its rotation speed. Quenching is continued, and finally, after the other moving induction heating coil on the other side makes one revolution, the quenching is finished at a position abutting close to the one stationary induction heating coil on the other side. In this case as well, each induction heating coil heats and quenches half the circumference of the raceway surface.

In this way, by relatively moving the pair of induction heating coils with respect to the raceway surface of the rotating raceway ring, a homogeneous hardened layer without a soft zone can be similarly formed on the raceway surface. .

[0021]

According to the method of quenching an orbital ring of the present invention, a pair of induction heating coils and a cooler that rotate in opposite directions on the circumferential surface of the orbital ring heat and rapidly cool the orbital surface, so that the entire circumference of the orbital surface is reheated. Without leaving a heating softening part and an unquenched soft zone,
A substantially homogeneous quench layer can be formed.

By arranging one pair or a plurality of pairs of induction heating coils, it is possible to easily realize high speed and high efficiency of the quenching treatment.

[Brief description of drawings]

FIG. 1 is a layout view in which a pair of induction heating coils according to an embodiment of the present invention are arranged around the outer circumference of a guide wheel inner ring. FIG. The rotation states are shown respectively.

FIG. 2 is a layout diagram (A, B) of the pair of induction heating coils at the quenching end position with respect to the inner ring.

FIG. 3 is a layout view in which two pairs of induction heating coils are arranged around the inner ring.

FIG. 4 is a partial sectional view of a bearing for swivel seat.

FIG. 5 is a partial perspective view of the inner peripheral surface of the outer ring when quenched by a single moving induction heating coil of a conventional example.

[Simple explanation of symbols]

 1 outer ring 2 inner ring 22 inner ring raceway surface 3 ball 51,52 induction heating coil 61,62 cooler 9 quenching layer 91 quenching start position 92 quenching end position

Claims (2)

[Claims] 1. A bearing ring of a large diameter bearing is attached to a support base,
A pair of induction heating coils with cooling means, which are close to the raceway surface of the raceway ring, are arranged so as to be relatively movable around the raceway ring, and heating and quenching is started from the raceway surface position where the pair of induction heating coils are brought close to each other. Then, the pair of induction heating coils are separated from each other and relatively rotated with respect to the bearing ring in opposite directions to perform heating and quenching, and the heating and quenching of the raceway surface is finished again at the raceway surface position where the pair of induction heating coils approach each other. A method for quenching a bearing ring, comprising: 2. The pair of induction heating coils constitutes one set, and a plurality of sets of induction heating coils are arranged so that each induction heating coil rotates in the opposite direction to another adjacent induction heating coil around the orbit ring. The method of quenching a bearing guide wheel according to claim 1, wherein the bearing guide wheel is provided.