JP2019002460A - Multiple-row rolling bearing and method of manufacturing the same - Google Patents

Abstract

To make a high frequency induction heat treatment apparatus cope with a multiple-row rolling bearing having numerous rows or a larger diameter without enlarging the high frequency induction heat treatment apparatus.SOLUTION: A multiple-row rolling bearing is manufactured by individually high frequency heat treating each of multiple raceway surfaces with leaving a non-treated part in an area between adjacent raceway surfaces.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a double row rolling bearing in which at least one raceway ring has a plurality of raceway surfaces and is integrated, and a manufacturing method thereof.

  FIG. 3 is a cross-sectional view showing an example of the double row ball bearing 1. The double-row ball bearing 1 includes a plurality of ball bearing surfaces on both raceway surfaces between outer raceway surfaces 6 and 6 formed on the inner peripheral surface of the outer ring 2 and inner ring raceway surfaces 7 and 7 formed on the outer peripheral surface of the inner ring 3. The balls 4 and 4 are individually held by the cages 5 and 5 so as to roll freely.

  In bearings, heat treatment is generally performed in order to increase the hardness of each raceway surface of the inner and outer rings. However, in addition to a method in which the outer ring and the inner ring are entirely heat treated by placing them in a heating furnace (furnace heating), High frequency heat treatment is also performed on the inner peripheral surface and the outer peripheral surface of the inner ring. The high-frequency heat treatment is a method of supplying a high-frequency current to the surface to be processed while moving the heating coil, and a hardened layer having a predetermined depth can be formed only on the surface to be processed at a predetermined depth. Therefore, compared with furnace heating, the heat treatment equipment can be downsized and the processing time can be shortened. In addition, if the workpieces are of various types with different sizes and materials, the heat treatment conditions are different, so it cannot be processed at once in the furnace heating, but in the high frequency heat treatment, it becomes a countermeasure for each workpiece. Even a variety of products can be handled easily.

  Regarding high-frequency heat treatment, for example, in Patent Document 1, an outer ring or an inner ring is arranged in a plurality of horseshoe-shaped heating coils, and a high-frequency current is supplied to the heating coil while rotating the outer ring or the inner ring in the circumferential direction. A hardened layer is formed at a predetermined depth on the inner and outer peripheral surfaces and the inner and outer peripheral surfaces of the inner ring.

JP 2005-325409 A

  However, in the double row rolling bearing, since the outer ring and the inner ring are wider than the single row rolling bearing, the heating coil used for the high frequency heat treatment becomes larger and the amount of power supply increases. In FIG. 3, the outer ring raceway surfaces 6 and 6 and the inner ring raceway surfaces 7 and 7 are each in two rows. However, when the raceway surface becomes, for example, four rows or multiple rows, or the bearing has a large diameter, such a problem occurs. Become prominent.

  The present invention has been made in view of such a situation, and an object of the present invention is to be able to cope with a multi-row or large-diameter double row rolling bearing without increasing the size of the high-frequency heat treatment apparatus.

In order to solve the above-mentioned problems, the present invention provides the following double-row rolling bearing and a manufacturing method thereof.
(1) In the double-row rolling bearing in which at least one of the races has a plurality of raceways and is integrated,
A double-row rolling bearing, wherein a surface layer of the raceway surface is a hardened portion, and a region between the adjacent raceway surfaces is a non-hardened portion.
(2) The double row rolling bearing according to (1), wherein the non-hardened portion is a two-phase mixed structure of ferrite and cementite.
(3) The double row rolling bearing according to the above (1) or (2), wherein the inner diameter is 1000 mm or more.
(4) The double-row rolling bearing according to (3), wherein the double-row rolling bearing is used for a bearing that supports a blade of a wind turbine generator.
(5) In the method of manufacturing a double row rolling bearing, wherein at least one of the bearing rings has a plurality of raceway surfaces and is integrated,
A method of manufacturing a double-row rolling bearing, comprising a heat treatment step of individually subjecting each of the raceway surfaces to high-frequency heat treatment while leaving a region between adjacent raceway surfaces.

  According to the present invention, since each of the raceway surfaces is individually subjected to high-frequency heat treatment while leaving a region between adjacent raceway surfaces, the processing apparatus can be increased in size even for multi-row and large-diameter double-row rolling bearings. There is no invitation. Moreover, since the non-hardened part which does not heat-process between the adjacent track surfaces is left, even if it processes a track surface separately, a hardening part does not overlap between adjacent track surfaces, and generation | occurrence | production of a crack can be prevented.

It is a partially cutaway perspective view showing an inner ring of a double row ball bearing as an example of the double row rolling bearing of the present invention. It is a figure for demonstrating the method to manufacture the double row ball bearing of FIG. It is a cross section which shows an example of a double row ball bearing.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  In the present invention, the type of the double row ball bearing is not limited, and for example, the double row ball bearing 1 shown in FIG. 3 can be exemplified. The double-row ball bearing 1 shown in FIG. 3 has double-row outer ring raceway surfaces 6 and 6 and inner ring raceway surfaces 7 and 7 for both the outer ring 2 and the inner ring 3. A split type in which a pair of inner rings having one row of inner ring raceway surfaces 7 are in contact with each other may be used.

  In the present invention, as shown in FIG. 1, a hardened layer (hatched portion in the figure) is formed on the inner ring raceway surfaces 7 and 7 of the inner ring 3 at a predetermined depth by high frequency heat treatment. This hardened layer becomes hardened portions 10 and 10. In addition, a hardened layer is not formed in the region between the inner ring raceway surfaces 7 and 7, and the non-hardened portion 11 is formed. Although not shown, a similar hardened layer is formed on the outer ring raceway surfaces 6 and 6 of the outer ring 2 to form the hardened portion 10, and the region between the outer ring raceway surfaces 6 and 6 is a non-hardened portion 11. And

  In order to form the hardened portions 10 and 10 on the surface layer of the inner ring raceway surfaces 7 and 7 and to make the region between the inner ring raceway surfaces 7 and 7 as the non-hardened portion 11 as shown in FIG. First, on one inner ring raceway surface 7 (right side in the example in the figure), a heating coil 20 having substantially the same width as the inner ring raceway surface 7 is disposed oppositely, and the heating coil 20 or the inner ring 3 is placed around the circumference of the inner ring 3. Heat treatment is performed by supplying a high-frequency current from the high-frequency power source 21 while moving in the direction. By this heat treatment, as shown in FIG. 1, a hardened portion 10 is formed on the surface layer of one inner ring raceway surface 7 and part of the region between the inner ring raceway surfaces 7 and 7 on the inner ring raceway surface side.

  Next, as shown in FIG. 2 (B), the same heating coil 20 as described above is disposed opposite to the other inner ring raceway surface 7 (left side in the example in the figure), and while the heating coil 20 or the inner ring 3 is moved, Heat treatment is performed by supplying a high-frequency current from the high-frequency power source 21. By this heat treatment, as shown in FIG. 1, a hardened portion 10 is formed on the surface layer of the other inner ring raceway surface 7 and a part on the inner ring raceway surface side of the region between both inner ring raceway surfaces 7 and 7, A non-hardened portion 11 is formed between the inner raceway surfaces 7 and 7.

  In this way, by individually subjecting the inner ring raceway surfaces 7 and 7 to high-frequency heat treatment using the same heating coil 20, the number of rows increases or the heating coil 20 is enlarged even for the inner ring 3 having a large diameter. Without heat treatment. Further, when the inner ring raceway surfaces 7 and 7 are individually heat-treated, cracks are generated when the already formed hardened portion 10 is subjected to a heat treatment, but in the region between the inner ring raceway surfaces 7 and 7. By leaving the non-cured portion 11, the cured portion 10 does not overlap and does not crack.

  Note that the depth of the hardened layer can be adjusted by the amount of power supplied to the heating coil 20 and the moving speed of the inner ring 3 or the heating coil 20, and the width of the non-hardened portion 11 can be adjusted.

  As described above, the double row ball bearing has been described as an example of the present invention. However, the present invention can be applied to a double row tapered roller bearing, a self-aligning roller bearing, a double row cylindrical roller bearing, and the like.

  Further, as described above, according to the present invention, since the high-frequency heat treatment is not increased, it is particularly useful for a large double-row rolling bearing having an inner diameter of 1000 mm or more, for example, a blade bearing for wind power generation.

  Furthermore, although there is no restriction | limiting in the base material of a bearing, For example, if it is steel used for bearing uses including SUJ2 and SUJ3, the non-hardening part 11 will become a two-phase mixed structure of a ferrite and cementite. These can be used.

DESCRIPTION OF SYMBOLS 1 Double row ball bearing 2 Outer ring 3 Inner ring 4 Ball 6 Outer ring raceway surface 7 Inner ring raceway surface 10 Curing part 11 Non-hardening part 20 Heating coil 21 High frequency power supply

Claims (5)

In a double row rolling bearing in which at least one raceway ring has a plurality of raceway surfaces and is integrated,
A double-row rolling bearing, wherein a surface layer of the raceway surface is a hardened portion, and a region between the adjacent raceway surfaces is a non-hardened portion.   The double row rolling bearing according to claim 1, wherein the non-hardened portion is a two-phase mixed structure of ferrite and cementite.   The double row rolling bearing according to claim 1 or 2, wherein the inner diameter is 1000 mm or more.   4. The double row rolling bearing according to claim 3, wherein the double row rolling bearing is used for a bearing for supporting a blade of a wind power generator. In the method of manufacturing a double row rolling bearing, wherein at least one of the races has a plurality of raceways and is integrated,
A method of manufacturing a double-row rolling bearing, comprising a heat treatment step of individually subjecting each of the raceway surfaces to high-frequency heat treatment while leaving a region between adjacent raceway surfaces.

Images