JP2013103260A - Method for manufacturing bearing raceway ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a bearing raceway ring which can improve production efficiency and material yield.SOLUTION: After a first disc-like material B1 is preformed, a forming blank B3 provided with a cylindrical outer cylinder 3 and a bottomed cylindrical inner cylinder 4 is formed by forging. The bottom 43 of the inner cylinder 4 of the forming blank B3 is punched out, and then the boundary between the center of the outer cylinder 3 of the blank and that of the inner cylinder 4 is shorn in the axial direction by forging to separate the both. The separated outer cylinder 3 and inner cylinder 4 are ground at a predetermined dimension, and their diameters are extended by cold rolling. Then, they are divided into two, respectively, at the center in the axial direction by grinding, to manufacture one set of material for outer ring and two sets of material for inner ring.

Description

  The present invention relates to a method for manufacturing a bearing race. In particular, the present invention relates to a method for manufacturing an outer ring shape material and an inner ring shape material of a rolling bearing in which one side in the axial direction of the bearing ring is thicker than the other side.

About race rings, such as a tapered roller bearing and an angular ball bearing, one side of an axial direction is formed thicker than the other side. An annular material for forming an outer ring of this type of rolling bearing (an outer ring shaped material) and an annular material for forming an inner ring (an inner ring shaped material) are usually manufactured through a forging process and a turning process (for example, Patent Document 1).
FIG. 6 is a process diagram showing a conventional example of a method for manufacturing a shaped member for an outer ring and a shaped member for an inner ring of a tapered roller bearing.
In this manufacturing method, first, as shown in FIGS. 6 a to 6 c, the columnar material A made of bearing steel or the like is crushed in the axial direction by, for example, hot forging, and the intermediate material 100 having an arc-shaped outer peripheral surface is obtained. Then, the intermediate material 100 is further crushed in the axial direction by hot forging to form a disk-shaped material 101 whose outer peripheral surface is parallel to the axial direction.

  Next, after the disk-shaped material 101 is preformed into a predetermined shape by hot forging (see FIG. 6d), the preform 102 is molded, and the inner periphery gradually becomes thicker toward the lower end. A blank 105 is obtained in which a cylindrical outer cylinder portion 103 and a bottomed cylindrical inner cylinder portion 104 having a flange 104a at the outer peripheral upper end are integrally formed (see FIG. 6e). Next, after punching out the bottom 104b of the inner cylindrical portion 104 of the blank 105 (see FIG. 6f), the boundary between the outer cylindrical portion 103 and the flange portion 104a of the inner cylindrical portion 104 is sheared to separate them ( See FIG. 6g). Thereafter, the outer cylinder part 103 and the inner cylinder part 104 separated from each other are respectively turned to form the outer ring shaped material and the inner ring shaped material having predetermined dimensions.

JP 11-244983 A ([0055] paragraph and FIG. 6)

Since the conventional method for manufacturing a bearing ring is a method in which the outer cylinder portion 103 and the inner cylinder portion 104 are integrally formed by forging and then separated from each other, the production efficiency is higher than when forging them separately. Can be increased. However, in recent years, there has been a demand for further improving the production efficiency of bearing races and reducing the cost.
Further, since the bottom 104b punched out of the inner cylinder 104 is discarded as a scrap, there is a problem that the material yield is poor.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a bearing race that can further improve the production efficiency and can secure a good material yield. .

  In order to achieve the above object, the bearing ring manufacturing method according to the present invention comprises a rolling bearing outer ring shape member and an inner ring shape member in which one side in the axial direction of the bearing ring is thicker than the other side. It is a method of manufacturing, forging a disk-shaped material made of steel, and the outer periphery is gradually expanded from the central portion in the axial direction toward the both ends, and the outer periphery is from the central portion in the axial direction. Obtained in the molding step, which obtains a blank having a bottomed cylindrical inner cylinder part that is gradually reduced in diameter toward both end parts and the central part is integrated with the central part of the outer cylinder part, and Punching the bottom of the inner cylindrical portion of the blank by forging, and the boundary between the central portion of the outer cylindrical portion and the central portion of the inner cylindrical portion of the blank punched out from the bottom of the inner ring in the axial direction by forging. A separation step of separating the outer tube portion and the inner tube portion by shearing; A machine finishing process for machining the inner cylinder part and the outer cylinder part separated in the separation process to finish them to a predetermined size, and dividing the outer cylinder part and the inner cylinder part into two in the center in the axial direction. A two-part dividing step of forming two sets of the outer ring shaped material and the inner ring shaped material in this order.

  According to the manufacturing method of the bearing race of the above-described configuration, the outer cylinder part and the inner cylinder part obtained by forging one disc-shaped material are each divided into two at the center in the axial direction. Since two sets of the base material for the inner ring and the base material for the inner ring are formed, the bearing race is compared with the conventional manufacturing method of manufacturing one set of the outer ring base material and the inner ring base material from one disk-shaped material. The production efficiency of the wheel can be increased. Also, since only one punched residue is generated for each two inner ring shaped members, the material yield is greatly increased compared to the conventional manufacturing method in which one removed residue is generated for each inner ring shaped member. Can do.

In the method for manufacturing the bearing race, a diameter increasing step for expanding the outer cylinder part and the inner cylinder part between the separation process and the machine finishing process or between the machine finishing process and the two-divided process. Further, it may be included.
In this case, since the outer inner diameter of the outer tube portion and the inner tube portion can be forged in a state smaller than the inner and outer diameters of the outer ring shaped material and the inner ring shaped material, which are the finished products, The outer diameter of the punched debris at the bottom of the cylindrical portion can be reduced. For this reason, the material yield can be further increased.

  The diameter increasing step for expanding the outer cylinder part and the inner cylinder part is preferably performed by cold rolling. In this case, the outer cylinder part and the inner cylinder part can be efficiently expanded with high accuracy.

The method for manufacturing the bearing ring further includes a pre-forming step of forming a disk-shaped material having a convex portion on the bottom side of the bottomed cylindrical inner cylinder portion by forging as a pre-step of the forming step. It is preferable.
In this case, in the subsequent molding step, the outer cylinder portion and the inner cylinder portion can be molded with high accuracy, and an excessive load can be suppressed from being applied to the molding die.

  According to the bearing race manufacturing method of the present invention, the production efficiency of the bearing race can be improved satisfactorily, and a good material yield can be secured.

It is process drawing which shows the forge process of the manufacturing method of the bearing race which concerns on this invention. It is process drawing which shows the turning process of an outer cylinder part. It is process drawing which shows the turning process of an inner cylinder part. It is sectional drawing which looked at the cold rolling process from the axial direction. It is sectional drawing which looked at the cold rolling process from the radial direction. It is process drawing which shows the manufacturing method of the conventional bearing race.

Hereinafter, a method for manufacturing a bearing race according to the present invention will be described in detail with reference to the drawings.
The bearing race ring manufacturing method according to the present invention is a method for manufacturing an outer ring shape material and an inner ring shape material of a rolling bearing in which one axial side of the bearing ring is thicker than the other side.
In the embodiment of the present invention shown in FIG. 1 to FIG. 5, a method for manufacturing a shaped member for an outer ring and a shaped member for an inner ring of a tapered roller bearing is illustrated.

<Upsetting process>
FIG. 1 is a cross-sectional view showing a forging process in the method for manufacturing a bearing race of the present invention.
In the method for manufacturing a bearing race according to the present invention, first, a columnar material 1 made of steel is subjected to upset forging to form a first disk-shaped material B1 (see FIGS. 1a to 1c). As the columnar material 1, bearing steel as bearing steel is used. The upsetting forging is performed by crushing the cylindrical material 1 in the axial direction by hot forging. This upsetting process is performed in two stages. That is, as the first stage, the columnar material 1 is crushed to about ½ of its entire length by free forging to form an intermediate material B0 having an arcuate outer peripheral surface, and as the second stage, the intermediate material B0 is further crushed by molding to obtain a first disc-shaped material B1 whose outer peripheral surface is parallel to the axial direction.

  The weight of the columnar material 1 is the weight necessary to obtain two sets of the outer ring shaped material B4 (see FIG. 2c) and the inner ring shaped material B5 (see FIG. 3c), It is set to a value obtained by adding a weight corresponding to a predetermined machining allowance (such as turning allowance and polishing allowance). Further, the outer diameter D1 of the first disc-shaped material B1 is set to a ratio of, for example, 80 to 95% with respect to the outer diameter of the outer ring shaped material B4 finally obtained. In addition, as said 1st disk shaped raw material B1, what shape | molded the outer peripheral surface in circular arc shape may be sufficient.

<Preliminary molding process>
Next, the first disk-shaped material B1 is die-forged to form a convex portion 2a on one surface (the lower surface in FIG. 1) of the first disk-shaped material B1 (preliminary molding step: FIG. 1d). reference). In this pre-molding step, the shallow concave portion 2b is compression-molded on the other surface (upper surface in FIG. 1) of the disk-shaped material B1, and at the same time, the convex portion 2a is formed by protruding. The outer diameter D2 and the thickness W2 of the part excluding the convex portion 2a of the preform (hereinafter referred to as “second disk-shaped material B2”) are the outer diameter D1 and the thickness W1 of the first disk-shaped material B1, respectively. Is almost the same.
In the preforming step, the annular groove 2c is recessed and formed at the base end of the convex portion 2a simultaneously with the formation of the convex portion 2a.

<Molding process>
When the preliminary molding step is completed, the second disk-shaped material B2 is die-forged to form a molding blank B3 in which the outer cylinder portion 3 and the inner cylinder portion 4 are integrally molded (molding step: see FIG. 1e). .
The outer periphery of the outer cylinder portion 3 extends in parallel with the axial direction, and the inner periphery thereof is gradually expanded from the axial central portion 31 having a predetermined width toward both ends. The outer diameter D3 of the outer cylindrical portion 3 is substantially the same as the outer diameter D2 of the second disc-shaped material B2, and the width W3 of the outer cylindrical portion 3 is the width of the second disc-shaped material B2. It is larger than W2.

The inner cylinder portion 4 has a bottomed cylindrical shape, and the outer periphery thereof is gradually reduced in diameter from the axial center portion 41 having a predetermined width toward both ends. The central portion 41 of the inner cylindrical portion 4 is continuous with the central portion 31 of the outer cylindrical portion 3 in a state of projecting annularly outwardly from the inclined surfaces 42 on both sides thereof. That is, the inner cylinder part 4 is integrated with the center part 31 of the outer cylinder part 3 through the annular center part 41. The inner cylinder portion 4 is formed concentrically with the outer cylinder portion 3.
The outer diameter D4 at both ends of the inner cylindrical portion 4 is substantially the same as the outer diameter D5 at the tip of the convex portion 2a of the second disc-shaped material B2, and the width W4 of the inner cylindrical portion 4 is 2 is larger than the full width W5 of the disc-shaped material B2.

  In the molding step, since the second disk-shaped material B2 in which the convex portions 2a are formed by preforming is used, compared to the case where the first disk-shaped material B1 in which the convex portions 2a are not formed is used. The outer cylinder part 3 and the inner cylinder part 4 can be formed with high accuracy. Further, since the load required for molding can be reduced, the load on the mold can be reduced. For this reason, durability of a shaping | molding die can be improved.

<Punching process>
When the molding step is completed, the bottom 43 of the inner cylinder portion 4 of the molding blank B3 is punched by forging (punching step: see FIG. 1f).
This punching step is performed by inserting a punch into the inner periphery of the inner cylinder part 4 and abutting against the bottom part 43 while holding the outer cylinder part 3 and the inner cylinder part 4.

When the punching process is completed, the boundary between the center portion 31 of the outer tube portion 3 and the center portion 41 of the inner tube portion 4 of the molding blank B3 is axially sheared by forging, so that the outer tube portion 3 and the inner tube portion. 4 is separated (separation step: see FIG. 1g). The separation between the outer cylinder part 3 and the inner cylinder part 4 is performed by inserting a punch into the outer cylinder part 3 and holding it against the upper end surface of the inner cylinder part 4 while holding the outer cylinder part 3. Do.
In addition, each above process can be performed continuously and efficiently by hot forging using a multistage former.

<Machine finishing process>
Next, the outer cylinder part 3 and the inner cylinder part 4 separated from each other are subjected to turning as machining to finish them to a predetermined dimension (see FIGS. 2a and 3a). This turning process is performed on the entire surface of the outer tube portion 3 and the inner tube portion 4. However, the width dimension of the outer cylinder part 3 and the inner cylinder part 4 may be finished to a predetermined dimension by grinding using a double-head grinding machine or the like instead of the turning process.

<Diameter expansion process>
When the machining of the outer cylinder part 3 and the inner cylinder part 4 is completed, these are expanded in diameter by plastic working. This diameter expansion is performed by performing a cold rolling process.
FIG. 4 is a schematic view showing the cold rolling process of the outer cylinder portion 3. In this cold rolling process, the outer cylinder portion 3 is sandwiched and rolled between the forming roll 51 and the mandrel 52, thereby reducing the wall thickness and expanding the inner and outer diameters to a predetermined dimension. The surface is formed into a predetermined shape. In this cold rolling process, the outer diameter of the outer cylinder portion 3 is detected by a sensor, and the rolling amount is controlled so that the outer diameter falls within a predetermined range. After this cold rolling process is completed, sizing is performed on the outer cylinder portion 3 as necessary to adjust the inner and outer diameter dimensions. Thereby, about the outer cylinder part 3, it can shape | mold into the shape which made the end surface of the thick side of two outer ring-shaped member B4 (refer FIG. 2c) face each other via the cutting margin 33 (FIG. 2b).

  The inner cylinder portion 4 that has been machined is also cold-rolled in the same manner as the outer cylinder portion 3 to expand the inner and outer diameters to a predetermined size and at the same time finish the outer peripheral surface to a predetermined shape. Thereby, the inner cylinder part 4 can be made into the shape which made the end surfaces by the side of the thick side of the two inner ring-shaped shape materials B5 (refer FIG. 3c) face each other via the cutting margin 44 (refer FIG. 3b). ). Note that the raceway side end face 45a of the large collar portion 45 (see FIG. 3c) of the inner ring-shaped member B5 has a so-called undercut shape, so this portion is subjected to turning after cold rolling and is undercut. Finish.

  Thus, since the process of expanding the diameters of the outer cylinder part 3 and the inner cylinder part 4 is performed by cold rolling, these can be efficiently expanded, and the outer cylinder part 3 and the inner cylinder part 4 Can be finished with a high precision into a predetermined shape.

<Bipart process>
When the diameter expansion process is completed, the outer cylindrical portion 3 and the inner cylindrical portion 4 are divided into two parts by machining the axially central cutting margins 33 and 44 of the outer cylindrical portion 3 and the inner cylindrical portion 4. (See FIGS. 2c and 3c). As this machining, turning using a stick tool or grinding using a thin disc-shaped grindstone can be employed.
As described above, two sets of the outer ring shaped material B4 and the inner ring shaped material B5 for the tapered roller bearing can be manufactured (see FIGS. 2c and 3c). These outer ring shaped material B4 and inner ring shaped material B5 are used as an outer ring and an inner ring of a tapered roller bearing by heat-treating and then polishing a predetermined portion.

According to the manufacturing method of the bearing race of the present invention, two sets of the outer ring shaped material 4 and the inner ring shaped material 5 can be formed from one disk-shaped material B1. The production efficiency of the bearing race can be increased as compared with a conventional manufacturing method for manufacturing a pair of outer ring shape material and inner ring shape material from a raw material. In addition, since only one punched residue is generated for each of the two inner ring shaped members B5, the material yield is greatly increased as compared with the conventional manufacturing method in which one punched residue is generated for each one of the inner ring shaped members. be able to.
Moreover, after forging the outer cylinder part 3 and the inner cylinder part 4 in a state where the diameter is smaller than the finished dimension, the diameter is expanded to a predetermined dimension by cold rolling, so that the bottom 43 of the inner cylinder part 4 is punched out. The outer diameter of the punched residue can be reduced. For this reason, a material yield can be raised more effectively.

In the above-described embodiment, the outer cylinder part 3 and the inner cylinder part 4 separated from each other are machined and finished to a desired dimension, and then subjected to cold rolling to increase the diameter. The outer cylinder part 3 and the inner cylinder part 4 may be finished to desired dimensions by performing a cold rolling process on the machined part and then performing a machining process in a subsequent process.
Further, as a method of expanding the diameters of the outer cylinder part 3 and the inner cylinder part 4 separated from each other, a method of expanding the diameter by forging process in which a punch is inserted in each inner periphery is adopted instead of the cold rolling process. can do.

  Furthermore, as the columnar material 1, other bearing steel such as carburized steel can be adopted in addition to the above-described bearing steel. In particular, when carburized steel is employed, cold forging and warm forging can be easily employed as forging in each step. Further, depending on the material of the columnar material 1, the preliminary forming step can be omitted.

In the said embodiment, although the diameter expansion process is included, this can be abbreviate | omitted and implemented. In this case, in the forging process, a forming blank B3 having a size obtained by adding a machining allowance to the outer diameter, the inner diameter, and the width of the outer ring shaped material B4 and the inner ring shaped material B5 is formed.
The bearing ring manufacturing method of the present invention includes a rolling ring bearing ring in which one side in the axial direction is thicker than the other side, such as a ring for an annular ball bearing, in addition to the above-described blank for a bearing ring of a tapered roller bearing. It can apply and implement as a manufacturing method of.

1: Cylindrical material 2a: Convex part 3: Outer cylinder part 4: Inner cylinder part 43: Bottom part of inner cylinder part B1: First disc material B2: Second disc material B3: Molding blank B4: For outer ring Shape material B5: Shape material for inner ring

Claims (4)

A method of manufacturing a shaped member for an outer ring and a shaped member for an inner ring of a rolling bearing in which one side in the axial direction of the bearing ring is thicker than the other side,
Forging a disk-shaped material made of steel, the outer circumference of the inner circumference gradually increases from the axial center to both ends, and the outer circumference gradually shrinks from the axial center to both ends. A molding step of obtaining a blank having a bottomed cylindrical inner cylinder portion having a diameter and the central portion integrated with the central portion of the outer cylinder portion;
A punching process in which the bottom of the inner cylinder part of the blank obtained in the molding process is punched by forging;
A separation step of separating the outer cylinder part and the inner cylinder part by forging the boundary between the center part of the outer cylinder part of the blank and the center part of the inner cylinder part in the axial direction by forging by punching the bottom part of the inner ring. When,
A machine finishing step of machining the inner cylinder portion and the outer cylinder portion separated in the separation step, and finishing to a predetermined dimension;
A two-part dividing step in which the outer cylinder part and the inner cylinder part are divided into two at the center in the axial direction, and a pair of outer ring shaped material and inner ring shaped material are formed;
In this order.   The bearing race according to claim 1, further comprising a diameter expanding step for expanding a diameter of the outer cylindrical portion and the inner cylindrical portion between the separation step and the mechanical finishing step or between the mechanical finishing step and the two-part dividing step. Manufacturing method.   The method for manufacturing a bearing race according to claim 2, wherein the diameter expansion step is performed by cold rolling.   The pre-forming step according to any one of claims 1 to 3, further comprising a pre-forming step of forming a disk-shaped material having a convex portion on the bottom side of the bottomed cylindrical inner cylinder portion by forging as a pre-step of the forming step. Manufacturing method of bearing race.

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