JP2012045577A - Method for manufacturing outer ring of conical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for picking two outer rings from one base stock to allow a raceway surface to be parallel with a metal flow of the base stock in manufacturing the outer ring of a conical roller bearing.SOLUTION: The outer ring of the conical roller bearing is made through: a step of making a disk-like base stock 110 by upsetting a columnar rod material 100; a step of making an annular base stock 150 by expanding an inner circumferential surface outward while an outer circumferential surface is fixed after drilling the center of the disk-like base stock 110; and a step of picking the two outer rings from the annular base stock 150 so that mutual end surfaces at a roller large diameter side are faced with each other with a flat surface for dividing the width of the annular base stock 150 into two as a center and the raceway surface is directed to an inner circumferential side to allow an angle formed by the mutual raceway surfaces to be <180°.

Description

  The present invention relates to a method for manufacturing an outer ring of a tapered roller bearing, and is particularly suitable for manufacturing an outer ring of a tapered roller bearing for a work roll of a steel rolling mill.

  Since the tapered roller bearing for work rolls of a steel rolling mill is used in a water environment, it is known that the bearing life is short and most of the damaged portion is an outer ring (see Non-Patent Document 1). Conventionally, the relationship between the raceway surface of the raceway and the metal flow (forging line) formed during processing has been studied. In order to suppress damage to the raceway surface of the raceway, Are more preferably parallel.

  For example, in Patent Document 1, the rigidity of the housing is weak, such as a tapered roller bearing for work rolls, and bending stress is generated during use, the outer ring is deformed, or the lubricating oil film is cut off due to the ingress of rolling water, resulting in the raceway surface. For bearings used in harsh environments such as tangential forces, at least one of the inner and outer rings should be within ± 15 ° of the rolling direction of the rolling element in order to extend the life. Propose to do. In Patent Document 2, the angle formed between the tangent at the contact point of the raceway groove in the cross section including the axis and the straight line indicating the direction of the metal flow on the most surface side of the raceway groove in the cross section is 0 ° or more. It describes that the forging conditions are set so as to be 60 ° or less.

Japanese Patent No. 3610598 JP 2006-250317 A

Matsumoto, Y, Murakami, Y, Oohori, M “Rolling Contact Fatigue Under Water-Infiltrated Lubrication”, Bearing Steel Technology, ASTM STP 1419, JM Beswick, Ed., American Society for Testing and Materials International, West Conshohoken, PA, 2002 P231 L18-19

  However, in each of the above methods, an optimal metal flow must be generated by changing the forging conditions for each design of the inner and outer rings. In particular, since the raceway surface of the outer ring of a tapered roller bearing is inclined, it is difficult to cut out from the material so that the raceway surface is parallel to the metal flow, and it is more difficult to cut out multiple outer rings from one material. become.

  Accordingly, an object of the present invention is to provide a method of cutting two outer rings from one material so that the raceway surface is parallel to the metal flow of the material in the manufacture of the outer ring of the tapered roller bearing.

In order to achieve the above-described reduction, the present invention provides the following method for manufacturing the outer ring of a tapered roller bearing.
(1) A method of manufacturing an outer ring of a tapered roller bearing,
A process of making a disk-shaped material by upsetting a cylindrical bar; and
After drilling the center of the disc-shaped material, a step of creating an annular material by spreading the inner peripheral surface outward with the outer peripheral surface fixed,
Two outer rings from the annular material, the roller large-diameter side end surfaces face each other around the plane that bisects the width of the annular material, and the raceway surfaces face the inner peripheral side, and the raceway surfaces A step of cutting out so that the angle formed by is less than 180 °,
A method for manufacturing an outer ring of a tapered roller bearing, comprising:
(2) The method for manufacturing a tapered roller bearing according to (1), wherein the method is for manufacturing an outer ring of a tapered roller bearing for a work roll of a steel rolling mill.

  According to the present invention, the metal flow of the material and the raceway surface of the outer ring to be obtained are nearly parallel, and two high-strength outer rings can be obtained simultaneously from one material.

FIG. 1 is a cross-sectional view showing an example of a tapered roller bearing for a work roll of a steel rolling mill. It is process drawing for demonstrating the manufacturing method of this invention. It is a figure which shows the other example of upsetting according to FIG.2 (b). It is a figure which shows the cutting modes other than this invention at the time of cutting out an outer ring | wheel from a raw material according to FIG.2 (e). It is a figure which shows the cutting modes other than this invention at the time of cutting out an outer ring | wheel from a raw material according to FIG.2 (e). It is a figure which shows the cutting modes other than this invention at the time of cutting out an outer ring | wheel from a raw material according to FIG.2 (e). It is a figure which shows the cutting modes other than this invention at the time of cutting out an outer ring | wheel from a raw material according to FIG.2 (e). It is a figure which shows the cutting modes other than this invention at the time of cutting out an outer ring | wheel from a raw material according to FIG.2 (e).

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

  FIG. 1 is a cross-sectional view showing an example of a tapered roller bearing 1 for work rolls (hereinafter simply referred to as a “conical roller bearing”) of a steel rolling mill. Outer rings 10, 10, inner rings 11, 11, tapered rollers 12, 12 disposed between the outer rings 10, 10 and the inner rings 11, 11, and cages 13, 13 that support these tapered rollers 12, 12. Outer ring spacers 14a and 14b disposed between the outer rings, seal holders 15 and 15 disposed at the ends of the outermost outer rings 10 and 10, and a seal 16 supported by the seal holders 15 and 15, 16 and an intermediate seal 17 held in a recess formed in an inner diameter surface of a portion where the pair of inner rings 11 and 11 are in contact with each other. The roll shaft 20 is fitted to the inner rings 11, 11.

  In the present invention, the outer ring 10 is manufactured according to the following steps.

  First, as shown in FIG. 2A, a columnar material 100 is prepared. For convenience, the metal flow is indicated by a symbol Mf. Since such a columnar material 100 is formed by extrusion, it is parallel to the axis as shown. The material is not limited as long as it can be plastically processed and can be quenched, and may be any material conventionally used for outer ring materials such as medium carbon steel, bearing steel, and carburized steel.

  Next, the columnar material 100 is hot upset. As shown in FIG. 2 (b), the upsetting process compresses in the vertical direction in the figure and expands the diameter in the radial direction to obtain a disk-shaped material 110. As shown in the figure, the disk-shaped material 110 usually has a maximum diameter at the center in the thickness direction and is almost barrel-shaped. Accordingly, the metal flow Mf in the disk-shaped material 110 is greatly curved at the center in the thickness direction.

  Next, as shown in FIG. 2C, in a state where the annular fixing frame 120 is arranged on the outer peripheral surface of the disk-shaped material 110, the cylindrical pressing member 130 is pushed in along the axis. As a result, the curvature of the curvature of the metal flow Mf increases as shown in the drawing, and the metal flow Mf approaches the axis line parallel to the outer peripheral side.

  Next, the bottom portion 111 is removed by punching, and as shown in FIG. 2D, the inner diameter is expanded with heat in a state where an annular fixing frame 140 is disposed on the outer peripheral surface. As a result, the raised portion 112 formed on the upper surface on the outer periphery side in FIG. 2C is pushed outward and shaped so as to have a substantially rectangular cross section, and the annular material 150 is obtained. Accordingly, the curvature radius of the curvature of the metal flow Mf becomes larger as shown in the figure, and the metal flow Mf approaches the parallel to the axis on the outer peripheral side.

  Next, the annular material 150 is cut out according to the outer ring shape. In FIG. 2 (e) (enlarged view of portion A in FIG. 2 (d)), the cutout shape is indicated by the symbol K, and K1 is a portion corresponding to the roller large-diameter side end surface (10b in FIG. 1) of the outer ring, K2 is a portion corresponding to the raceway surface (10a in FIG. 1) of the outer ring, and K3 is a portion corresponding to the outer circumferential surface (10c in FIG. 1). In the present invention, in order to cut out two outer rings, two roller large-diameter side end surface equivalent portions K1 face each other around a plane H that divides the width of the annular material 150 into two, and two track surface equivalent portions Cutting is performed so that K2 faces the inner peripheral side and the angle α formed between the portions corresponding to the raceway surfaces is less than 180 °. In the annular material 150, the curvature of the metal flow Mf is larger toward the inner peripheral side and closer to the axis line toward the outer peripheral side. Therefore, when such cutting is performed, the raceway surface equivalent portion K2 is cut out so as to face the curved metal flow Mf1 on the inner peripheral side, and the resulting raceway surface 10a of the outer ring 10 is made of a metal flow ( Mf1) is close to parallel. As a result, the mechanical strength of the raceway surface 10a is increased, and resistance to wear and the like associated with the rolling of the tapered roller is improved. Moreover, the outer peripheral surface 10c of the outer ring obtained is also substantially parallel to the material metal flow (Mf2).

  Thus, according to the manufacturing method of the present invention, the raceway surface 10a and the outer peripheral surface 10c are nearly parallel to the metal flow of the material, and a high-strength outer ring 10 is obtained. Further, two outer rings 10 can be obtained from one material.

  In the above, the degree of curvature (the radius of curvature) of the metal flow Mf can be controlled by adjusting the compression rate during upsetting shown in FIG. For example, as shown in FIG. 3, the metal flow Mf is greatly curved by increasing the compression rate, and the angle α formed by the track surface equivalent portion K2 is reduced at the time of the cutting process in FIG. By cutting out the two outer rings, the outer ring 10 having a large inclination angle of the raceway surface 10a can be manufactured. Also in this case, the raceway surface 10a becomes nearly parallel to the material metal flow Mf, and a high-strength outer ring 10 is obtained.

  On the other hand, for example, as shown in FIG. 4, even if the two outer rings are cut out from the cylindrical material 100 with the cutout shape K in FIG. 2E without upsetting, the metal flow Mf is parallel to the axis. Therefore, the inclined track surface equivalent portion K2 and the metal flow Mf intersect each other.

  Further, as shown in FIG. 5, when one outer ring is cut out from the annular material 150, the metal flow Mf and the track surface equivalent portion K2 intersect.

  FIG. 6 is a diagram showing a case where three outer rings are cut out. In the cutout shape K, the middle stage and the lower stage are set to a cutout shape K in which the roller large-diameter end face equivalent portion K1 is opposed, and the upper stage is the large-diameter side In the style of the cutout shape K with the end surface equivalent portion K1 directed to the opposite side, the track surface equivalent portion K2 and the metal flow Mf intersect at the upper stage and the middle stage.

  In addition, as shown in FIG. 7, when the two outer rings are cut out, the portion K4 corresponding to the roller small-diameter side end face (10d in FIG. 1) is opposed so that the angle α exceeds 180 °. The surface equivalent portion K2 and the metal flow Mf intersect each other.

  Also, as shown in FIG. 8, when the two outer rings are cut out in the radial direction of the material, the track surface equivalent portion K2 and the metal flow Mf intersect each other.

  Thus, even if it cuts out with the cutting shape K other than this invention, the outer ring | wheel 10 which has the track surface 10a parallel to the metal flow Mf of a raw material is not obtained.

  Then, the cut outer ring is chamfered and finished to obtain the final product.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and demonstrated further regarding this invention, this invention is not restrict | limited at all by this.

Example 1
According to the process shown in FIG. 2, an outer ring of Nippon Seiko Co., Ltd. tapered roller bearing “343KVS4551 (outer ring outer diameter φ457.098 mm, inner ring inner diameter φ343.052 mm, assembly width 254 mm, basic dynamic load rating 1530000 N)” was manufactured.

  That is, first, a columnar material made of SUJ2 and having a total length of 260 mm and a diameter of 140 mm was hot processed to obtain a barrel-shaped material (see FIG. 2B). Next, in a state where an annular fixing frame is disposed on the outer peripheral surface, a cylindrical pressing member is pushed in along the axis line in the hot state, and the bottom portion is punched (see FIG. 2 (c)). The inner diameter was expanded to obtain an annular material having an inner diameter of 416 mm, an outer diameter of 470 mm, and a thickness of 105 mm (see FIG. 2D). Next, as shown in FIG. 2 (e), the roller large diameter side end surface corresponding portion is cut from the annular material so that the angle α formed by the two track surface corresponding portions is 145 °. It was. Then, chamfering and finishing were performed to obtain a test outer ring A.

(Comparative Example 1)
After obtaining an annular material in the same manner as in Example 1, as shown in FIG. 7, two outer rings were cut out with the roller small-diameter side end face portions facing each other. Then, chamfering and finishing were performed to obtain a test outer ring B.

Using the test outer rings A and B, a four-row tapered roller bearing as shown in FIG. ^-1 Rotating under the condition that the amount of water injected into the bearing was 720 mL / h, the rotation was stopped when the detected vibration became twice the initial value, and flaking of the outer ring raceway surface was confirmed. The time until the rotation was stopped was measured as the life. The results are shown in Table 1. The rated fatigue life of this bearing is 505 hours, but when the test outer ring A of Example 1 is used, the life is extended more than twice compared with the case of using the test outer ring B of Comparative Example 1. The service life was longer than the rated fatigue life.

  As described above, the production of the outer ring of the tapered roller bearing for a work roll of a steel rolling mill has been described as an example mainly for the present invention, but it is effective in the production of the outer ring of a general tapered roller bearing, and has high strength and durability. It is clear that an outer ring excellent in the above can be obtained.

1 Tapered roller bearing for work roll 10 Outer ring 11 Inner ring 12 Tapered roller 13 Cage 16 Seal 20 Roll shaft Mf Metal flow

Claims (2)

A method of manufacturing an outer ring of a tapered roller bearing,
A process of making a disk-shaped material by upsetting a cylindrical bar; and
After drilling the center of the disc-shaped material, a step of creating an annular material by spreading the inner peripheral surface outward with the outer peripheral surface fixed,
Two outer rings from the annular material, the roller large-diameter side end surfaces face each other around the plane that bisects the width of the annular material, and the raceway surfaces face the inner peripheral side, and the raceway surfaces A step of cutting out so that the angle formed by is less than 180 °,
A method for manufacturing an outer ring of a tapered roller bearing, comprising:   2. The method for manufacturing a tapered roller bearing according to claim 1, wherein the method is for manufacturing an outer ring of a tapered roller bearing for a work roll of a steel rolling mill.

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