Patent ID: 12209614

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described with reference toFIGS.1to31. The reference numerals in parentheses correspond to the reference numerals shown in the description of the examples described later.

In an embodiment, a bearing element manufacturing method includes a first step of preparing a first piece (13,25,30,32,39) having a predetermined shape, a second step of obtaining a second piece (16,27,32,33,38,40) by processing the first piece (13,25,30,32,39), and a third step of obtaining a first ring element (11) and a second ring clement (12) which are separated from each other. The predetermined shape includes a first ring portion (13b,25a,30a,32a,39h) serving as a large diameter portion and a second ring portion (13c,25b,30b,32b,39c) serving as a small diameter portion and these ring portions are arranged side by side in the axial direction. In the predetermined shape, the inner diameter and the outer diameter of the first ring portion (13b,25a,30a,32a,39b) are larger than the inner diameter and the outer diameter of the second ring portion (13c,25b,30b,32b,39c). In the second step, the second piece (16,27,32,33,38,40) includes a third ring portion (16a,27a,32a,33a,38a,40a) corresponding to the first ring portion (13b,25a,30a,32a,39b) in the first step and a fourth ring portion (16b,27b,32b,33b,38b,40b) corresponding to the second ring portion (13c,25b,30b,32b,39c) in the first step. In the third step, the first ring element (11) serving as a large diameter ring element corresponds to the third ring portion (16a,27a,32a,33a,38a,40a) in the second step. In the third step, the second ring element (12) serving as a small diameter ring element corresponds to the fourth ring portion (16b,27b,32b,33b,38b,40b) in the second step. The second step includes preparing a first set (TS1) as a processing tool set, preparing a second set (TS2) as a processing tool set, and deforming the first piece (13,25,30,32,39) by using the first set (TS1) and the second set (TS2). The first set (TS1) includes a first member (17c,28c,34d) and a second member (17b,28b,34e) disposed inside or outside the first member (17c,28c,34d). The second set (TS2) includes a third member (17f,28f,34c) and a fourth member (17e,28e,34b) disposed inside or outside the third member (17f,28f,34c). At least temporarily in the second step, (a) the first piece (13,25,30,32,39) is disposed between the first set (TS1) and the second set (TS2) in the axial direction, (b) the first set (TS1) contacts a first axial surface (AF1) of the first piece (13,25,30,32,39), and (c) the second set (TS2) contacts a second axial surface (AF2) of the first piece (13,25,30,32,39). Due to the contact, the first piece (13,25,30,32,39) is held between the first set (TS1) and the second set (TS2) in the axial direction so that the axial movement is regulated. The first piece (13,25,30,32,39) is deformed by relatively moving the second member (17b,28b,34e) in the first axial direction with respect to the first member (17c,28c,34d) while maintaining the above (a), (b), and (c). Further, the first piece (13,25,30,32,39) is deformed by relatively moving the fourth member (17e,28e,34b) in the second axial direction with respect to the third member (17f,28f,34c) while maintaining the above (a), (b), and (c). The first axial direction and the second axial direction are parallel to each other. The second axial direction is opposite to the first axial direction. The first axial surface (AF1) and the second axial surface (AF2) face the opposite directions. The first axial surface (AF1) is disposed toward the first axial direction and the second axial surface (AF2) is disposed toward the second axial direction. The direction of the second axial surface (AF2) is opposite to the direction of the first axial surface (AF1).

In the manufacturing method including the first step, the second step, and the third step, the number of steps is smaller than that of the related art and two bearing elements (first ring element (11), second ring element (12)) independent from each other and having different diameters can be obtained from one material. In the second step, the axial dimension of the first ring portion (13b,25a,30a,32a,39b) serving as the large diameter portion and the axial dimension of the second ring portion (13c,25b,30b,32b,39c) serving as the small diameter portion are regulated by the first tool (TS1) and the second tool (TS2). This regulation is advantageous in reducing the amount of cutting and/or grinding in the post-treatment. Further, it is possible to realize multiple plastic workings (pressing) in the same step (so-called one chuck) without separating a workpiece (first piece) from a processing device by using the first set (TS1) and the second set (TS2) at the same time.

In an example, the movement of the second member (17b,28b,34e) and the movement of the fourth member (17e,28e,34b) are performed sequentially or performed at least temporarily simultaneously while the first piece (13,25,30,32,39) is disposed between the first set (TS1) and the second set (TS2) in the axial direction, that is, the above (a), (b), and (c) are maintained.

For example, in the first set (TS1), the second member (17b,28b,34e) is disposed inside the first member (17c,28c,34d) and the fourth member (17e,28e,34b) is disposed inside the third member (17f,28f,34c). For example, the outer diameter of the second member (17b,28b,34e) is substantially equal to the outer diameter of the fourth member (17e,28e,34b). For example, the second member (17b,28b,34e) and the fourth member (17e,28e,34b) which are disposed on both axial sides of the first piece (13,25,30,32,39) move toward the axial inside. For example, the second member (17b,28b,34e) and the fourth member (17e,28e,34b) move along the axial direction to be closer to each other. In accordance with the axial movement of the second member (17b,28b,34e) and the fourth member (17e,28e,34b), the first piece (13,25,30,32,39) is processed so that at least a part of the inner peripheral surface of the fourth ring portion (16b,27b,32b,33b,38b,40b) is defined.

In an example, the outer peripheral surface or the inner peripheral surface of the second member (17b,28b,34e) slides with respect to the inner peripheral surface or the outer peripheral surface of the first member (17c,28c,34d). For example, the inner peripheral surface or the outer peripheral surface of the first member (17c,28c,34d) faces the outer peripheral surface or the inner peripheral surface of the second member (17b,28b,34e).

In an example, at least one of the first member (17c,28c,34d) and the second member (17b,28b,34e) includes an inclined surface (17b1,17e1,28b1,28e1,34b3) which is inclined with respect to the axial direction and comes into press-contact with the first piece (13,25,30,32,39). For example, the inclined surface (17b1,17e1,28b1,28e1,34b3) is disposed to come into contact with the corner of the first piece (13,25,30,32,39). For example, when at least one of the second member (17b,28b,34e) and the fourth member (17e,28e,34b) moves, the corner of the first piece (13,25,30,32,39) is subjected to plastic working (pressing process) to be a chamfered portion by the inclined surface (17b1,17e1,28b1,28e1,34b3).

In an example, in the second step, the axial dimension of the first ring portion (13b,25a,30a,32a,39b) and the axial dimension of the second ring portion (13c,25b,30b,32b,39c) are regulated by the first tool (TS1) and the second tool (TS2) and the chamfered portion is formed by press forming. This regulation is advantageous in reducing the amount of cutting and/or grinding in the post-treatment step while suppressing the press load or the number of steps.

In an example, the deformation of the first piece (13,25,30,32,39) includes (a) forming a hole (axial hole) in the first piece (13,25,30,32,39), (b) shaving the inner peripheral surface or the outer peripheral surface of the first piece (13,25,30,32,39) in the axial direction, (c) processing the inner peripheral surface or the outer peripheral surface of the first piece (13,25,30,32,39) to gather an extra thickness in at least one position in the axial direction, and (d) forming a chamfered portion in the first piece (13,25,30,32,39). Two or more of the above-described processes are performed while the first piece (13,25,30,32,39) is sandwiched between the first set (TS1) and the second set (TS2) in the second step (one chuck). That is, multiple processes are performed in the same step without separating the workpiece (first piece) from the processing device.

In an embodiment, a bearing manufacturing method includes a step of manufacturing a bearing element according to the manufacturing method and this is advantageous in reducing the cost of the bearing.

In an embodiment, a machine manufacturing method includes a step of manufacturing a bearing element according to the manufacturing method and this is advantageous in reducing the cost of the machine having the bearing.

In an embodiment, a vehicle manufacturing method includes a step of manufacturing a bearing element according to the manufacturing method and this is advantageous in reducing the cost of the vehicle having the bearing.

In an embodiment, a bearing element has traces produced according to the bearing element manufacturing method. In an example, the trace is a metal flow (metal fiber flow, fibrous metal structure) observed in the cross-section of the bearing element.FIGS.29and30show an example of the metal flow in the axial cross-section of the bearing element.

In an embodiment, as shown inFIGS.29and30, the bearing element includes a body (2,11) having a ring shape. The body (2,11) includes a first chamfered portion (2b1) which is formed between an outer peripheral surface (2c,11c) and a first axial surface (2f1,11a1) and a second chamfered portion (2b2) which is formed between an outer peripheral surface (2c,11c) and a second axial surface (2f2,11a2). The metal flow of the body (2,11) includes a first pattern (MFP1) which is continuous along the first chamfered portion (2b1) in the vicinity of the surface of the first chamfered portion (2b1), a second pattern (MFP2) which is continuous along the second chamfered portion (2b2) in the vicinity of the surface of the second chamfered portion (2b2), and a third pattern (MFP3) which is continuous along the outer peripheral surface (2c,11c) in the vicinity of the outer peripheral surface (2c,11c). The third pattern (MFP3) is asymmetric (non-axisymmetric) with respect to a line (virtual line, ACL) passing through the axial center of the body (2,11) and along the radial direction. For example, in the third pattern (MFP3), the distance between the plurality of line elements is relatively wide in the region between the first axial surface (11a1) and the line (ACL) and is relatively narrow in the region between the first axial surface (11a1) and the line (ACL). Such a bearing element is advantageous in reducing the manufacturing cost.

In an example, the distance between the plurality of line elements in the third pattern (MFP3) changes to be gradually narrowed from the first axial surface (11a1) toward the second axial surface (11a2). For example, the first axial surface (11a1) is an axial end surface. The second axial surface (11a2) is an axial end surface. The second axial surface (11a1) is an opposite surface of a first axial surface (11a2).

In an example, the distance between the plurality of line elements in the first pattern (MFP1) is wider than the distance between the plurality of line elements in the second pattern (MFP2). An average value (first average value) of the distance between the plurality of lines in the first pattern (MFP1) is larger than an average value (second average value) of the distance of the plurality of lines in the second pattern (MFP2). For example, the first average value/the second average value can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, or 3.0 times or more.

In an example, the metal flow further includes a fourth pattern (MFP4) which is continuous along the first axial surface (11a1) in the vicinity of the first axial surface (11a1) and a fifth pattern (MFP5) which is continuous along the second axial surface (11a2) in the vicinity of the second axial surface (11a2).

In an example, the distance between the plurality of line elements in the fourth pattern (MFP4) is wider than the distance between the plurality of line elements in the fifth pattern (MFP5). An average value (fourth average value) of the distance between the plurality of lines in the fourth pattern (MFP4) is larger than an average value (fifth average value) of the distance between the plurality of lines in the fifth pattern (MFP5). For example, the fourth average value/the fifth average value can be 1.1, 1.2, 1.3, 1.4, 1.5. 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, or 3.0 times or more.

In an example, the line elements are continuous in at least three patterns of the first pattern (MFP1), the second pattern (MFP2), the third pattern (MFP3), the fourth pattern (MFP4), and the fifth pattern (MFP5). The line element having a continuous metal flow is advantageous in increasing the strength of the body (2,11).

In an example, each of the fourth pattern (MFP4) and the fifth pattern (MFP4) includes a plurality of line elements intersecting the inner peripheral surface (2a,2g,11b) of the body (2,11).

In an embodiment, a bearing includes the bearing element and this is advantageous in reducing the cost of the bearing.

In an embodiment, a machine includes the bearing and this is advantageous in reducing the cost of the bearing.

In an embodiment, a vehicle includes the bearing and this is advantageous in reducing the cost of the bearing.

The above-described bearing element or bearing can be applied to, for example, bearings900A and900B supporting a rotation shaft963of a motor961shown inFIG.31.

InFIG.31, the motor961is a brushless motor and includes a cylindrical center housing965and a substantially disc-shaped front housing967which closes one opening end portion of the center housing965. The rotatable rotation shaft963is supported along the axis inside the center housing965through the bearings900A and900B disposed on the bottom portions of the front housing967and the center housing965. A motor driving rotor969is provided around the rotation shaft963and a stator971is fixed to the inner peripheral surface of the center housing965.

The motor961is generally mounted on a machine or a vehicle and rotationally drives the rotation shaft963supported by the bearings900A and900B.

The bearing element or bearing can he applied to machines and various manufacturing devices having a rotation portion, for example, a rotation support portion of a screw device such as a ball screw device and a linear motion device such as an actuator (a combination of a linear motion guide bearing and a ball screw, an XY table, or the like). Further, the bearing element or bearing can be applied to a steering device such as a wiper, a power window, an electric door, an electric seat, a steering column (for example, an electric tilt telcsco steering column), a universal joint, an intermediate gear, a rack and pinion, an electric power steering device, and a worm reducer. Furthermore, the bearing element or bearing can be applied to various vehicles such as automobiles, motorcycles, and railways. The bearing having this configuration can be suitably applied to a portion that rotates relative to each other, which can lead to improvement in product quality and cost reduction.

As the bearing provided with the bearing element, various types such as a rolling bearing and a sliding bearing can be suitably applied. For example, the bearing element. can be applied to outer and inner races of a radial rolling bearing, outer and inner races of a radial cylindrical roller bearing using a cylindrical roller (including needle), and outer and inner races of a radial tapered roller bearing using a tapered roller.

First Example

A first example of the present invention will be described with reference toFIGS.1to11. This example is an example in which the present invention is applied to a method of manufacturing an outer race2and an inner race3constituting a radial rolling bearing1. The radial rolling bearing1includes, as shown inFIG.1, the outer race2having an outer race track2aformed on an inner peripheral surface, the inner race3having an inner race track3aformed on an outer peripheral surface, and a plurality of rolling elements4arranged between the outer race track2aand the inner race track3ain a rollable manner.

Additionally, the radial rolling bearing1of this example is composed of a single row deep groove type ball bearing using a ball as the rolling element4.

The outer race2includes radially outer chamfered portions2b1and2b2which are formed at the connection portions between the outer peripheral surface and both axial end surfaces to be inclined in a direction in which the outer diameter dimension decreases as it goes toward the axial outside. In this example, the radially outer chamfered portions2b1and2b2are formed as conical surfaces each having a linear generatrix shape. However, the radially outer chamfered portion may be formed as a convex curved surface having an arcuate generatrix shape.

Additionally, in the radial rolling bearing1, the axial outside means the outside (both sides) of the radial rolling bearing1in the width direction and the axial inside means the center side of the radial rolling bearing1in the width direction.

The entire outer peripheral surface of the outer race2including the radially outer chamfered portions2b1and2b2is formed as a forged surface that has not been finished by a grinding process or the like.

The inner race3includes radially inner chamfered portions3b1and3b2which are formed at the connection portions between the inner peripheral surface and both axial end surfaces to be inclined in a direction in which the inner diameter dimension increases as it goes toward the axial outside. In this example, the radially inner chamfered portions3b1and3b2are formed as conical surfaces each having a linear generatrix shape. However, the radially inner chamfered portion can be formed as a convex curved surface having an arcuate generatrix shape.

At least a portion provided with the radially inner chamfered portions3b1and3b2in the inner peripheral surface of the inner race3is formed as a forged surface that has not been finished by a grinding process or the like.

The outer race2and the inner race3of this example are manufactured by performing cold plastic working on a single columnar material (billet)10to obtain a large diameter cylindrical member (first ring element, bearing element)11and a small diameter cylindrical member (second ring element, bearing element)12having different diameter dimensions and performing a necessary post-treatment (finishing) such as a cold rolling (CRF) process, a cutting process, a grinding process, and a heat treatment on the large diameter cylindrical member11and the small diameter cylindrical member12. A method of manufacturing the large diameter cylindrical member11and the small diameter cylindrical member12will be described with reference toFIGS.4to10.

In this example, the columnar material (billet)10shown inFIG.4(A)is sequentially subjected to an upsetting process and a front-rear extruding process to obtain a preliminary intermediate material (first piece)13shown inFIG.4(C)and the preliminary intermediate material13is subjected to plastic working to obtain the large diameter cylindrical member11and the small diameter cylindrical member12. In this example, the total number of steps of manufacturing the large diameter cylindrical member11and the small diameter cylindrical member12from the single columnar material10is eight steps by including a step of cutting a long wire to a predetermined length to obtain the columnar material10, a step of performing an upsetting process on the columnar material10to obtain a preliminary material14shown inFIG.4(B), and a step of extruding the preliminary material14in the front and rear direction to obtain the preliminary intermediate material13.

Hereinafter, each step will be described in order.

Additionally, in the example shown in the drawings, the axial direction of the workpiece (the columnar material10, the large diameter cylindrical member11, and the small diameter cylindrical member12) is disposed in the vertical direction (the up and down direction), but the axial direction of the workpiece can be disposed in an arbitrary direction. That is, for example, the axial direction of the workpiece can be disposed in the horizontal direction or a direction inclined with respect to the vertical direction and the horizontal direction.

Further, unless otherwise specified, the axial direction means the axial direction of the workpiece, one axial side means the side of the large diameter cylindrical portion13bof the preliminary intermediate material13, and the other axial side means the side of the small diameter cylindrical portion13cof the preliminary intermediate material13.

First, in a first step (cutting step), a long wire drawn from an uncoiler is cut to a predetermined length to obtain the columnar material10as shown inFIG.4(A).

In a second step (upsetting step), the outer diameter dimension of the columnar material10is expanded while the columnar material is crushed in the axial direction to obtain the thick disc-shaped or beer barrel-shaped preliminary material14shown inFIG.4(B)in which the outer diameter dimension of the axial intermediate portion is larger than the outer diameter dimensions of both axial portions.

In a third step (front-rear extruding step), the preliminary material14is subjected to a front-rear extruding process of axially extruding a thick portion (metal material) existing on both axial sides and the radial outside while the center portions of both axial end surfaces of the preliminary material14are crushed to approach each other in the axial direction to obtain the preliminary intermediate material13shown inFIG.4(C). The preliminary intermediate material13(first piece) includes a disc-shaped side plate portion13a, a large diameter cylindrical portion (first ring portion)13bwhich protrudes from the radially outer portion of one axial surface (the upper surface ofFIG.4(C)) of the side plate portion13atoward one axial side, and a small diameter cylindrical portion (second ring portion)13cwhich protrudes from the radial intermediate portion of the other axial surface (the lower surface ofFIG.4(C)) of the side plate portion13atoward the other axial side.

The large diameter cylindrical portion13bhas an outer diameter dimension equal to the outer diameter dimension of the large diameter cylindrical member11to be obtained. Additionally, the inner diameter dimension of the large diameter cylindrical portion13bdoes not need to be equal to the inner diameter dimension of the large diameter cylindrical member11to he obtained and is preferably smaller than the inner diameter dimension of the large diameter cylindrical member11.

The small diameter cylindrical portion13chas an outer diameter dimension equal to the outer diameter dimension of the small diameter cylindrical member12to be obtained. Additionally, the inner diameter dimension of the small diameter cylindrical portion13cdoes not need to be equal to the inner diameter dimension of the small diameter cylindrical member12to be obtained and is preferably smaller than the inner diameter dimension of the small diameter cylindrical member12.

The third step is performed by using a press working device15shown inFIG.5. The press working device15includes a die15a, a mandrel15b, and a punch15c.

The die15aincludes an inner peripheral surface having a shape along the outer peripheral surface shape of the preliminary intermediate material13to be obtained. That is, the die15aincludes a stepped cylindrical inner peripheral surface formed by connecting a large diameter portion15a1on one axial side (the upper side ofFIG.5) to a small diameter portion15a2on the other axial side (the lower side ofFIG.5) with a stepped surface15a3facing one axial side.

The mandrel15bis disposed at the center portion of the small diameter portion15a2of the die15a.

The punch15cis supported by the support table (not shown) of the press working device15to be axially displaceable.

In order to obtain the preliminary intermediate material13by performing a front-rear extruding process on the preliminary material14using the press working device15, first, the preliminary material14is placed on the stepped surface15a3of the die15aand the tip surface (one axial end surface) of the mandrel15b. Next, the punch15cis displaced toward the other axial side so that the tip surface (the other axial end surface) of the punch15cpresses the center portion of the preliminary material14. Accordingly, the thick portion on the radially outer portion of the preliminary material14is moved to a portion between the outer peripheral surface of the mandrel15band the small diameter portion15a2and the thick portion at the radial intermediate portion of the preliminary material14is moved to a portion between the outer peripheral surface of the punch15cand the large diameter portion15a1to obtain the preliminary intermediate material13while the center portion of the preliminary material14is crushed between the tip surface of the punch15cand the tip surface of the mandrel15b.

In a next fourth step, the preliminary intermediate material13is subjected to a small diameter side dimension regulating process of regulating the axial dimension of the small diameter cylindrical portion13cto a predetermined dimension Ls (seeFIG.6) and forming the radially inner chamfered portions3b1and3b2at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion13cto obtain a first intermediate material16shown inFIG.4(D). The first intermediate material (second piece)16includes a large diameter cylindrical portion (third ring portion)16aon one axial side, a small diameter cylindrical portion (fourth ring portion)16bon the other axial side, a connection plate portion16cconnecting the other axial end portion of the large diameter cylindrical portion16aand the other axial end portion of the small diameter cylindrical portion16b, and a partition wall portion16ddividing one axial portion on the radial inside of the small diameter cylindrical portion16b. The small diameter cylindrical portion16bincludes the radially inner chamfered portions3b1and3b2which are formed at the connection portion between the inner peripheral surface and both axial end surfaces.

Additionally, in this example, in the fourth step, the large diameter cylindrical portion13bof the preliminary intermediate material13is not subjected to plastic working. However, in the example shown in the drawings, for convenience of description, the large diameter cylindrical portion13bof the preliminary intermediate material13and the large diameter cylindrical portion16aof the first intermediate material16are indicated by different reference numerals.

The fourth step is performed by using a press working device17shown inFIG.6. The press working device17includes a die17a, an inner pressing punch (second member)17b, an outer pressing punch (first member)17c, a presser punch17d, an inner counter punch (fourth member)17e, and an outer counter punch (third member)17f.

The die17aincludes an inner peripheral surface having a shape along the outer peripheral surface shape of the first intermediate material16to be obtained. In this example, the inner peripheral surface shape of the die17ais the same as the inner peripheral surface shape of the die15aused in the front-rear extruding process (third step). That is, the die17aincludes a stepped cylindrical inner peripheral surface formed by connecting a large diameter portion17a1on one axial side to a small diameter portion17a2on the other axial side with a stepped surface17a3facing one axial side. However, the inner peripheral surface shape of the die used in the small diameter side dimension regulating process can be different from the inner peripheral surface shape of the die used in the front-rear extruding process.

The inner pressing punch17bhas a columnar shape and is supported at the center portion of the large diameter portion17a1of the die17ato be axially displaceable with respect to the support table (not shown) of the press working device17. The inner pressing punch17bincludes a chamfer forming portion (inclined surface)17b1formed at the tip portion (the other axial end portion, the lower end portion ofFIG.6) to have a shape along one axial radially inner chamfered portion3b1of the pair of radially inner chamfered portions3b1and3b2formed at the small diameter cylindrical portion16bof the first intermediate material16. That is, in this example, the chamfer forming portion17b1has a linear generatrix shape.

The outer pressing punch17chas a cylindrical shape and is supported around the inner pressing punch17bto be axially displaceable with respect to the support table.

The presser punch17dhas a cylindrical shape and is supported around the outer pressing punch17cto be axially displaceable with respect to the support table.

The inner counter punch17ehas a columnar shape and is supported at the center portion of the small diameter portion17a2of the die17ato be axially displaceable with respect to the support table (not shown) of the press working device17. The inner counter punch17eincludes a chamfer forming portion (inclined surface)17e1formed at the tip portion (one axial end portion, the upper end portion ofFIG.6) to have a shape along the other axial radially inner chamfered portion3b2of the pair of radially inner chamfered portions3b1and3b2formed at the small diameter cylindrical portion161) of the first intermediate material16. That is, in this example, the chamfer forming portion17e1has a linear generatrix shape.

The outer counter punch17fhas a cylindrical shape and is supported to be axially displaceable with respect to the support table. The outer counter punch17fis inserted between the small diameter portion17a2of the die17aand the outer peripheral surface of the inner counter punch17esubstantially without a gap (without a gap into which a thick portion forming the preliminary intermediate material13intrudes when the preliminary intermediate material13is processed into the first intermediate material16).

In order to obtain the first intermediate material16by performing a small diameter side dimension regulating process on the preliminary intermediate material13using the press working device17, first, the radially outer portion of the other axial surface of the side plate portion13aof the preliminary intermediate material13is placed on the stepped surface17a3of the die17a. Then, the presser punch17dis displaced toward the other axial side so that the presser punch17dpresses one axial end surface of the large diameter cylindrical portion13bof the preliminary intermediate material13(the large diameter cylindrical portion13bis sandwiched between the stepped surface17a3of the die17aand the presser punch17din the axial direction).

In this state, the inner pressing punch17band the outer pressing punch17care displaced toward the other axial side and the inner counter punch17eand the outer counter punch17fare displaced toward one axial side. Then, the small diameter cylindrical portion13cof the preliminary intermediate material13is axially crushed between the group of the inner pressing punch17band the outer pressing punch17cand the group of the inner counter punch17eand the outer counter punch17f. Accordingly, the axial dimension of the small diameter cylindrical portion13cis regulated to a predetermined dimension Ls and the radially inner chamfered portions3b1and3b2are formed at the same time at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion13cby the chamfer forming portion17e1of the inner counter punch17eand the chamfer forming portion17b1of the inner pressing punch17b.

Additionally, at this time, the tip surface of the inner pressing punch17bpresses a portion located on the radial inside in relation to the small diameter cylindrical portion13cin the side plate portion13aof the preliminary intermediate material13so to be offset toward the other axial side with respect to the radially outer portion of the side plate portion13a. Accordingly, the radially inner portion of the side plate portion13ais the partition wall portion16dand the radially outer portion of the side plate portion13ais the connection plate portion16c. In other words, in this example, the partition wall portion16dcorresponds to a portion which is punched out and removed by a punching process to be described later and is located on the radial inside in relation to the inner peripheral surface of the small diameter cylindrical portion13cin the side plate portion13a. As described above, the first intermediate material16is obtained.

In a next fifth step, the first intermediate material16is subjected to a large diameter side dimension regulating process of regulating the axial dimension of the large diameter cylindrical portion16ato a predetermined dimension Lb (seeFIG.7) and a first large diameter side chamfering process of forming the other axial radially outer chamfered portion2b2at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion16ato obtain a second intermediate material18shown inFIG.4(E). The second intermediate material18includes one axial large diameter cylindrical portion18a, the other axial small diameter cylindrical portion18b, a connection plate portion18cconnecting the other axial end portion of the large diameter cylindrical portion18ato one axial end portion of the small diameter cylindrical portion18b, and a partition wall portion18ddividing one axial portion on the radial inside of the small diameter cylindrical portion18b. The small diameter cylindrical portion18bincludes the radially inner chamfered portions3b1and3b2which are formed at the connection portion between the inner peripheral surface and both axial end surfaces and the large diameter cylindrical portion18aincludes the other axial radially outer chamfered portion2b2which is formed at the connection portion between the outer peripheral surface and the other axial end surface.

Additionally, in this example, in the fifth step, a portion other than the large diameter cylindrical portion16a, that is, the small diameter cylindrical portion16b, the connection plate portion16c, and the partition wall portion16dof the first intermediate material16are not subjected to plastic working. However, in the example shown in the drawings, for convenience of description, the small diameter cylindrical portion16b, the connection plate portion16c, and the partition wall portion16dof the first intermediate material16and the small diameter cylindrical portion18b, the connection plate portion18c, and the partition wall portion18dof the second intermediate material18are indicated by different reference numerals.

The fifth step is performed by using a press working device19shown inFIG.7. The press working device19includes a die19a, a pressing punch19b, a mandrel19c, and a sleeve19d.

The die19aincludes a stepped cylindrical inner peripheral surface which includes one axial large diameter portion19a1, the other axial small diameter portion19a2, and a stepped surface19a3bent from one axial end portion of the small diameter portion19a2toward the radial outside to face one axial side. The stepped surface19a3includes a flat surface portion19a3awhich is disposed on the radial inside and is orthogonal to the center axis of the die19aand a conical chamfer forming portion19a3bwhich is disposed on the radial outside and is inclined toward one axial side as it goes toward the radial outside.

The pressing punch19bhas a cylindrical shape and is supported to be axially displaceable with respect to the support table (not shown) of the press working device19. The pressing punch19bis fitted into the large diameter portion19a1of the die19asubstantially without a gap.

The mandrel19chas a columnar shape and is supported inside the large diameter portion19a1of the die19ato be axially displaceable with respect to the support table.

The sleeve19dhas a cylindrical shape and is supported inside the small diameter portion19a2of the die19ato be axially displaceable with respect to the support table.

In order to obtain the second intermediate material18by performing a large diameter side dimension regulating process and a first large diameter chamfering process on the first intermediate material16using the press working device19, first, the connection plate portion16cof the first intermediate material16is placed on the stepped surface19a3of the die19a. Then, the mandrel19cis displaced toward the other axial side (the lower side ofFIG.7) so that the tip surface (the other axial end surface) of the mandrel19cpresses the end surface on one axial side (the upper side ofFIG.7) of the small diameter cylindrical portion16bof the first intermediate material16. Further, the sleeve19dis displaced toward one axial side so that the tip surface (one axial end surface) of the sleeve19dis allowed to contact or closely face the other axial end surface of the small diameter cylindrical portion16bof the first intermediate material16.

In this state, the pressing punch19bis displaced toward the other axial side so that the large diameter cylindrical portion16aof the first intermediate material16is axially crushed between the stepped surface19a3of the die19aand the tip surface (the other axial end surface) of the pressing punch19b. Accordingly, the axial dimension of the large diameter cylindrical portion16ais regulated to a predetermined dimension Lb and the radially outer chamfered portion2b2is formed at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion16aby the chamfer forming portion19a3b. As described above, the second intermediate material18is obtained.

In the next sixth step, the second intermediate material18is subjected to a punching process of punching out and removing the partition wall portion18dand a small diameter side shaving process of shaving the small diameter cylindrical portion18bto obtain a third intermediate material20shown inFIG.4(F). The third intermediate material20includes one axial large diameter cylindrical portion20a, the other axial small diameter cylindrical portion20b, and a connection plate portion20cconnecting the other axial end portion of the large diameter cylindrical portion20ato one axial end portion of the small diameter cylindrical portion20b. The small diameter cylindrical portion20bincludes the radially inner chamfered portions3b1and3b2formed at the connection portion between the inner peripheral surface and both axial end surfaces and the large diameter cylindrical portion20aincludes the other axial radially outer chamfered portion2b2formed at the connection portion between the outer peripheral surface and the other axial end surface.

Additionally, in this example, in a sixth step, the outer peripheral surfaces of the large diameter cylindrical portion18a, the connection plate portion18c, and the small diameter cylindrical portion18bof the second intermediate material18are not subjected to plastic working. However, in the example shown in the drawings, for convenience of description, the large diameter cylindrical portion18aand the connection plate portion18cof the second intermediate material18and the large diameter cylindrical portion20aand the connection plate portion20cof the third intermediate material20are indicated by different reference numerals.

The sixth step is performed by using a press working device21shown inFIG.8. The press working device21includes a die21a, a shaving cutter21b, and a presser punch21c.

The die21aincludes a cylindrical inner peripheral surface.

The shaving cutter21bhas a columnar shape and is supported at the center portion of the axially outer portion (the lower portion ofFIG.8) of the die21ato be axially displaceable with respect to the support table (not shown) of the press working device21. The shaving cutter21bhas an outer diameter dimension which is substantially equal to the inner diameter dimension of the small diameter cylindrical portion20bof the third intermediate material20to be obtained and includes a blade portion21b1which is formed at the radially outer edge of the tip portion (one axial end portion, the upper end portion ofFIG.8) to perform a shaving process of slightly scraping the surface of the inner peripheral surface of the small diameter cylindrical portion18bof the second intermediate material18to be smooth on the inner peripheral surface and to punch out the partition wall portion18d.

The presser punch21chas a substantially cylindrical shape and is supported at the center portion of one axial portion (the upper portion ofFIG.8) of the die21ato be axially displaceable with respect to the support table.

In order to obtain the third intermediate material20by performing a punching process and a small diameter side shaving process on the second intermediate material18using the press working device21, the second intermediate material18is disposed inside the die21ato regulate the displacement toward one axial side by the presser punch21c. In this state, the shaving cutter21bis displaced toward one axial side so that the blade portion21b1slightly scrapes (shaves) the inner peripheral surface of the small diameter cylindrical portion18bto be smooth and punches out the partition wall portion18dand the partition wall portion18dis simultaneously removed (taken out) from one axial opening of the small diameter cylindrical portion18b. More specifically, the shaving cutter21bis inserted from the other axial opening of the small diameter cylindrical portion18band is displaced toward one axial side so that the surface of the inner peripheral surface of the axially outer portion of the small diameter cylindrical portion18bis slightly scraped to be smooth. Then, the tip portion of the shaving cutter21bis brought into contact with the other axial surface of the partition wall portion18d. When the shaving cutter21bis further displaced toward one axial side from this state, the partition wall portion18dis punched out and the surface of the portion provided with the partition wall portion18d(the portion connected to the radially outer end portion of the partition wall portion18d) in the inner peripheral surface of the small diameter cylindrical portion18bis slightly scraped to be smooth. As described above, the third intermediate material20is obtained.

In a next seventh step, the third intermediate material20is subjected to a separating process of separating the large diameter cylindrical portion20a(and the connection plate portion20c) and the small diameter cylindrical portion20bfrom each other to obtain a preliminary large diameter cylindrical member22and a small diameter cylindrical member12shown inFIG.4(6). The preliminary large diameter cylindrical member22includes a large diameter cylindrical portion22aand an inward flange portion22bbent from the other axial end portion of the large diameter cylindrical portion22atoward the radial inside. The small diameter cylindrical member12has an outer diameter dimension smaller than the inner diameter dimension of the large diameter cylindrical portion22aof the preliminary large diameter cylindrical member22and includes the radially inner chamfered portions3b1and3b2formed at the connection portion between both axial end surfaces and the inner peripheral surface by the fourth step.

Additionally, in this example, in the seventh step, the third intermediate material20is just divided into the large diameter cylindrical portion20a, the connection plate portion20c, and the small diameter cylindrical portion20b, but is not subjected to plastic working that changes each shape. However, in the example shown in the drawings, for convenience of description, the large diameter cylindrical portion20aof the third intermediate material20and the large diameter cylindrical portion22aof the preliminary large diameter cylindrical member22are indicated by different reference numerals.

Further, in the example shown in the drawings, the seventh step is performed while the direction with respect to the axial direction of the third intermediate material20to be processed in the seventh step is inverted (to rotate by 180°) from the direction with respect to the axial direction of the third intermediate material20processed in the sixth step. However, the seventh step can be also performed while the direction with respect to the axial direction of the third intermediate material20to be processed in the seventh step is the same as the direction with respect to the axial direction of the third intermediate material20in the sixth step.

The seventh step is performed by using a press working device23shown inFIG.9. The press working device23includes a die23a, a sleeve23b, a presser punch23c, and a punching punch23d.

The die23aincludes a cylindrical inner peripheral surface.

The sleeve23bis supported by one axial portion (the lower portion ofFIG.9) of the die23a.

The presser punch23chas a cylindrical shape and is supported at the center portion of the axially outer portion (the upper portion ofFIG.9) of the die23ato be axially displaceable with respect to the support table (not shown) of the press working device23.

The punching punch23dhas a columnar shape and is supported at the center portion of the die23ato be axially displaceable with respect to the support table.

In order to obtain the preliminary large diameter cylindrical member22and the small diameter cylindrical member12by performing a separating process on the third intermediate material20using the press working device23, first, one axial end surface of the large diameter cylindrical portion20aof the third intermediate material20is disposed on the other axial end surface of the sleeve23bdisposed inside the die23a. Then, the presser punch23cis displaced (moved downward) toward one axial side so that the tip surface (one axial end surface) of the presser punch23cpresses the other axial end surface of the large diameter cylindrical portion20aof the third intermediate material20and the other axial surface of the connection plate portion20c. In this state, the punching punch23dis displaced toward the other axial side so that the small diameter cylindrical portion20bof the third intermediate material20is punched out and is separated from the large diameter cylindrical portion20aand the connection plate portion20c. Accordingly, the preliminary large diameter cylindrical member22and the small diameter cylindrical member12are obtained. Additionally, the small diameter cylindrical member12of them is taken out from the press working device23and is set to the post-treatment step.

In a next eighth step (final press step), a large diameter side shaving process of shaving the inner peripheral surface of the preliminary large diameter cylindrical member22and a second large diameter side chamfering process of forming one axial radially outer chamfered portion2b1at the connection portion between one axial end surface and the inner peripheral surface of the large diameter cylindrical portion22aare performed to obtain the large diameter cylindrical member11shown inFIG.4(H). The large diameter cylindrical member11has a cylindrical shape and includes the radially outer chamfered portions2b1and2b2formed at the connection portion between both axial end surfaces and the outer peripheral surface.

Additionally, in the eighth step, the outer peripheral surface of the preliminary large diameter cylindrical member22is not subjected to plastic working.

The eighth step is performed by using a press working device24shown inFIG.10. The press working device24includes a die24a, a sleeve24b, and a shaving cutter24c.

The die24aincludes a cylindrical inner peripheral surface.

The sleeve24bincludes a conical chamfer forming portion24b1which is formed at the radially outer portion of the other axial end surface to be inclined toward the other axial side as it goes toward the radial outside and is supported by one axial portion (the lower portion ofFIG.10) of the die24a.

The shaving cutter24chas a columnar shape and is supported at the center portion of the axially outer portion (the upper portion ofFIG.10) of the die21ato be axially displaceable with respect to the support table (not shown) of the press working device24. The shaving cutter24chas an outer diameter dimension substantially equal to the inner diameter dimension of the large diameter cylindrical member11to be obtained and includes a blade portion24c1which is formed at the radially outer edge of the tip portion (one axial end portion) to perform a shaving process of slightly scraping the surface of the inner peripheral surface to be smooth on the inner peripheral surface of the large diameter cylindrical portion22aof the preliminary large diameter cylindrical member22.

In order to obtain the large diameter cylindrical member11by performing a large diameter side shaving process on the preliminary large diameter cylindrical member22using the press working device24, first, one axial end surface of the preliminary large diameter cylindrical member22is placed on the other axial end surface of the sleeve24bdisposed inside the die24a. Next, the shaving cutter24cis displaced toward one axial side. Accordingly, the inner peripheral surface of the large diameter cylindrical portion22aof the preliminary large diameter cylindrical member22is slightly scraped to be smooth, the inward flange portion22bis punched out to be removed, and the connection portion between the outer peripheral surface and one axial end surface of the large diameter cylindrical portion22ais simultaneously pressed against the chamfer forming portion24b1of the sleeve24bto form one axial radially outer chamfered portion2b1. As described above, the large diameter cylindrical member11is obtained.

In the post-treatment step, the inner peripheral surface of the large diameter cylindrical member11is subjected to a cold rolling process or a cutting process to form the outer race track2a. If necessary, a locking groove for locking a seal member is formed. If necessary, a heat treatment such as quenching is performed to obtain the outer race2. However, in this example, the outer peripheral surface of the large diameter cylindrical member11is not subjected to a machining process such as a cutting process or a grinding process in the post-treatment step. Thus, the entire outer peripheral surface of the outer race2including the radially outer chamfered portions2b1and2b2is formed as a forged surface that has not been finished by a grinding process or the like.

In the post-treatment step, the outer peripheral surface of the small diameter cylindrical member12is subjected to a cold rolling process or a cutting process to form the inner race track3a. If necessary, a groove to contact the tip portion of the seal member is formed. If necessary, a heat treatment such as quenching is performed to obtain the inner race3. However, in this example, at least the radially inner chamfered portions3b1and3b2formed at end portion at both axial sides in the inner peripheral surface of the small diameter cylindrical member12are not machined by a cutting process or a grinding process in the post-treatment step. Thus, at least a portion provided with the radially inner chamfered portions3b1and3b2in the inner peripheral surface of the inner race3is formed as a forged surface that has not been finished by a grinding process or the like.

In the manufacturing method of this example, in the process in which one columnar material10is subjected to press working into the large diameter cylindrical member11and the small diameter cylindrical member12, the axial dimension of the large diameter cylindrical portion16ais regulated to a predetermined dimension Lb so that the axial dimension of the completed large diameter cylindrical member11is regulated and the axial dimension of the small diameter cylindrical portion13cis regulated to a predetermined dimension Ls so that the axial dimension of the completed small diameter cylindrical member12is regulated. Therefore, it is not necessary to cut or grind the axial surface of the large diameter cylindrical member11or it is possible to suppress the amount of cutting or grinding to a small amount in order to regulate the axial dimension of the large diameter cylindrical member11to a desired dimension when processing the large diameter cylindrical member11into the outer race2. Further, it is not necessary to cut or grind the axial surface of the small diameter cylindrical member12or it is possible to suppress the amount of cutting or grinding to a small amount in order to regulate the axial dimension of the small diameter cylindrical member12to a desired dimension when processing the small diameter cylindrical member12into the inner race3. Thus, it is possible to reduce the manufacturing cost of the outer race2and the inner race3.

In the manufacturing method of this example, in the process of processing the columnar material10into the large diameter cylindrical member11and the small diameter cylindrical member12, the pair of radially outer chamfered portions2b1and2b2is formed in the large diameter cylindrical member11by press working and the pair of radially inner chamfered portions3b1and3b2are formed in the small diameter cylindrical member12by press working. Thus, it is not necessary to form the chamfered portion at the connection portion between the outer peripheral surface and both axial end surfaces of the large diameter cylindrical member and the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical member by a cutting process or the like after obtaining the large diameter cylindrical member and the small diameter cylindrical member which are the materials of the outer race and the inner race. From this aspect as well, it is possible to reduce the manufacturing cost of the outer race2and the inner race3.

In the manufacturing method of this example, in the sixth step, a punching process of punching out and removing the partition wall portion18dand a small diameter side shaving process of shaving the small diameter cylindrical portion18bare performed. Accordingly, a portion provided with the partition wall portion18din the inner peripheral surface of the small diameter cylindrical portion18bis also subjected to a shaving process after the partition wall portion18dis punched out. In short, the shear and fracture surfaces formed on the inner peripheral surface of the small diameter cylindrical portion18bby punching out the partition wall portion18dcan be shaved to be smooth. Therefore, it is possible to satisfactorily ensure the dimension accuracy of the inner peripheral surface of the small diameter cylindrical portion20bof the third intermediate material20(the inner peripheral surface of the small diameter cylindrical member12).

In the manufacturing method of this example, a separating process of separating the large diameter cylindrical portion20a(and the connection plate portion20c) and the small diameter cylindrical portion20bfrom each other is performed in the seventh step and then a large diameter side shaving process of shaving the inner peripheral surface of the preliminary large diameter cylindrical member22is performed in the eighth step. Thus, the shear and fracture surfaces formed on the inner peripheral surface of the connection plate portion20ccan be shaved to be smooth by separating the small diameter cylindrical portion20bfrom the large diameter cylindrical portion20a(and the connection plate portion20c). Therefore, it is possible to satisfactorily ensure the dimension accuracy of the inner peripheral surface of the large diameter cylindrical member11.

In the manufacturing method of this example, the axial dimension of the small diameter cylindrical portion13cis regulated to a predetermined dimension Ls and the radially inner chamfered portions3b1and3b2are simultaneously formed at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion13c. Therefore, it is possible to reduce the number of steps of manufacturing the large diameter cylindrical member11and the small diameter cylindrical member12from the columnar material10. As a result, it is possible to reduce the manufacturing cost of the large diameter cylindrical member11and the small diameter cylindrical member12and further the manufacturing cost of the outer race2and the inner race3. Specifically, the manufacturing method of this example can be easily performed by, for example, a former (multi-stage forging machine).

Further, in the manufacturing method of this example, in the fifth step, a large diameter side dimension regulating process of regulating the axial dimension of the large diameter cylindrical portion16ato a predetermined dimension and a first large diameter side chamfering process of forming the other axial radially outer chamfered portion2b2in the large diameter cylindrical portion16aare performed at the same time. Further, in the eighth step, a large diameter side shaving process of shaving the inner peripheral surface of the preliminary large diameter cylindrical member22and a second large diameter side chamfering process of forming one axial radially outer chamfered portion2b1in the large diameter cylindrical portion22aof the preliminary large diameter cylindrical member22are performed at the same time. From this aspect as well, it is possible to reduce the number of steps of manufacturing the large diameter cylindrical member11and the small diameter cylindrical member12from the columnar material10and to reduce the manufacturing cost of the large diameter cylindrical member11and the small diameter cylindrical member12and further the manufacturing cost of the outer race2and the inner race3.

In the outer race2obtained by performing post-treatment on the large diameter cylindrical member11obtained by the manufacturing method of this example, the entire outer peripheral surface of the outer race2including the radially outer chamfered portions2b1and2b2is formed as a forged surface that has not been finished by a grinding process or the like. Thus, as shown in parts (A) and (B) ofFIG.2, a metal flow Foutin the outer race2is continuous (extends) along the radially outer chamfered portions2b1and2b2in the vicinity of the surfaces of the radially outer chamfered portions2b1and2b2(a portion from the surfaces of the radially outer chamfered portions2b1and2b2to the depth of about 20% to 30% of the outer diameter dimension of the outer race2).

Further, a portion deviated from the outer race track2atoward one axial side in the axial direction of the metal flow Foutin the outer race2is provided with a curved portion T which is curved toward the radial outside as it goes from the axial inside toward the axial outside and is changed in the direction of folding back about 180° toward the radial inside. This reason will be described with reference to parts (A) and (B) ofFIG.11.

When a thick disc-shaped or beer barrel-shaped preliminary material14is obtained by axially crushing the columnar material10obtained by cutting a long wire to a predetermined length, a metal flow F14in the preliminary material14is curved so that the axially intermediate portion bulges most toward the radial outside as shown inFIG.11(A). In other words, the metal flow F14extends toward the radial outside as it goes from one axial end portion toward the axially intermediate portion, folds back about 180° toward the radial inside at the axially intermediate portion, and extends toward the radial inside as it goes from the axially intermediate portion toward the other axial end portion.

Next, when the preliminary material14is subjected to a front-rear extruding process to obtain the preliminary intermediate material13, a metal flow F13in the preliminary intermediate material13is a flow shown inFIG.11(B). That is, the metal flow is substantially parallel to the center axis of the preliminary intermediate material13along the large diameter cylindrical portion13bfrom one axial end portion to the axially intermediate portion of the large diameter cylindrical portion13b. At the other axial end portion of the large diameter cylindrical portion13b. the metal flow is curved toward the radial outside and is changed (curved) in the direction of folding back about 180° (in a substantially U shape or V shape) toward the radial inside. That is, the metal flow F13has the curved portion T at the other axial end portion of the large diameter cylindrical portion13b.

Additionally, the metal flow F13at the side plate portion13a(excluding the connection portion between the large diameter cylindrical portion13band the small diameter cylindrical portion13c) is a flow in a direction substantially orthogonal to the center axis of the preliminary intermediate material13along the side plate portion13aand the metal flow at the small diameter cylindrical portion13c(excluding the connection portion with the side plate portion13a) is a flow substantially parallel to the center axis of the preliminary intermediate material13along the small diameter cylindrical portion13c.

In the manufacturing method of this example, the metal flow in the large diameter cylindrical member11may have the curved portion T in order to separate the large diameter cylindrical portion and the small diameter cylindrical portion from each other by performing a predetermined process on the preliminary intermediate material13and use the large diameter cylindrical portion as the large diameter cylindrical member11. Then, the curved portion T may remain as a trace also on the metal flow in the outer race2obtained by performing the post-treatment on the large diameter cylindrical member11. In other words, when the curved portion T exists in the metal flow in the outer race2, it can be estimated that the outer race2is manufactured from the large diameter cylindrical member obtained by the manufacturing method of this example.

Further, in the inner race3obtained by performing post-treatment on the small diameter cylindrical member12obtained by the manufacturing method of this example, at least a portion provided with the radially inner chamfered portions3b1and3b2in the inner peripheral surface is formed as a forged surface that has not been finished by a grinding process or the like. Thus, as shown inFIG.3, a metal flow Finin the inner race3is continuous (extends) along the radially inner chamfered portions3b1and3b2in the vicinity of the surfaces of the radially inner chamfered portions3b1and3b2(from the surfaces of the radially inner chamfered portions3b1and3b2to the depth of about 10% to 20% of the inner diameter dimension of the inner race3).

Additionally, when the large diameter cylindrical member and the small diameter cylindrical member obtained by the manufacturing method of this example are processed into the outer race and the inner race to form the radial rolling bearing, the outer race and the inner race constituting the radial rolling bearing may not be essentially obtained by processing the large diameter cylindrical member and the small diameter cylindrical member obtained from the same columnar material. That is, the rolling bearing can be obtained by combining the large diameter cylindrical member and the small diameter cylindrical member obtained from different columnar materials. Further, one of the large diameter cylindrical member and the small diameter cylindrical member is obtained by the manufacturing method of this example to be processed into the outer race or the inner race, the other of the large diameter cylindrical member and the small diameter cylindrical member is obtained by a different method to be processed into the inner race or the outer race, and the rolling bearing is obtained by combining them. That is, when there is a difference between the number of the large diameter cylindrical members and the number of the small diameter cylindrical members due to the occurrence of defective products during mass production, the outer race or the inner race manufactured from the large diameter cylindrical member or the small diameter cylindrical member obtained by different methods can be combined with each other.

Further, a pair of sliding bearings having different diameter dimensions can be manufactured from the large diameter cylindrical member and the small diameter cylindrical member obtained by the manufacturing method of this example. Specifically, a pair of sliding bearings is manufactured by performing a finishing process such as a grinding process on the surfaces (at least one of the outer peripheral surface, the inner peripheral surface, and both axial end surfaces) of the large diameter cylindrical member and the small diameter cylindrical member if necessary after the large diameter cylindrical member and the small diameter cylindrical member are obtained.

Additionally, the radial rolling bearings or sliding bearings manufactured from the large diameter cylindrical member and the small diameter cylindrical member obtained by the cylindrical member of this example are used by incorporating them into various rotating mechanical devices and vehicles.

Further, the press working devices15,17,19,21,23, and24used in the respective steps are not limited to the above-described configurations and may have any configuration as long as the workings in the respective steps can be performed.

Second Example

A second example of the present invention will be described with reference toFIGS.12to15. A first step to a third step, a seventh step, and an eighth step in a manufacturing method of this example are the same as the first step to the third step, the seventh step, and the eighth step of the first example. Hereinafter, a fourth step to a sixth step in the manufacturing method of this example will be described.

In the fourth step, the preliminary intermediate material13shown inFIG.12(C)is simultaneously subjected to three processes of a large diameter side dimension regulating process of regulating the axial dimension of the large diameter cylindrical portion13bto a predetermined dimension Lb (seeFIG.13), a first large diameter side chamfering process of forming the other axial radially outer chamfered portion2b2at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion13b, and a punching process of punching out and removing a portion located on the radial inside in relation to the small diameter cylindrical portion13cin the side plate portion13a. Accordingly, a first intermediate material25shown inFIG.12(D)is obtained.

The first intermediate material (first piece)25includes a large diameter cylindrical portion (first ring portion)25aon one axial side (the upper side ofFIG.12(D)), a small diameter cylindrical portion (second ring portion)25bon the other axial side (the lower side ofFIG.12(D)), and a connection plate portion25cconnecting the other axial end portion of the large diameter cylindrical portion25ato one axial end portion of the small diameter cylindrical portion25b. The large diameter cylindrical portion25aincludes the other axial radially outer chamfered portion2b2formed at the connection portion between the outer peripheral surface and the other axial end surface.

The fourth step is performed by using a press working device26shown inFIG.13. The press working device26includes a die26a, a pressing punch26b, and a punching punch26c.

The die26aincludes a stepped cylindrical inner peripheral surface which includes a large diameter portion26a1on one axial side (the upper side ofFIG.13), a small diameter portion26a2on the other axial side (the lower side ofFIG.13), and a stepped surface26a3bent from one axial end portion of the small diameter portion26a2toward the radial outside and facing one axial side. The stepped surface26a3includes a flat surface portion26a3adisposed on the radial inside and orthogonal to the center axis of the die26aand a conical chamfer forming portion26a3bdisposed on the radial outside and inclined toward one axial side as it goes toward the radial outside.

The pressing punch26bhas a cylindrical shape and is supported on the inside of the large diameter portion26a1of the die26ato be axially displaceable with respect to the support table (not shown) of the press working device26.

The punching punch26chas a columnar shape and is supported at the center portion of the die26ato be axially displaceable with respect to the support table.

In order to obtain the first intermediate material25by performing a large diameter side dimension regulating process, a first large diameter side chamfering process, and a punching process on the preliminary intermediate material13using the press working device26, first, the other axial surface of the side plate portion13aof the preliminary intermediate material13is placed on the stepped surface26a3of the die26a.

In this state, the pressing punch26bis displaced toward the other axial side so that the large diameter cylindrical portion13bof the preliminary intermediate material13is axially crushed between the stepped surface26a3of the die26aand the tip surface of the pressing punch261). Accordingly, the axial dimension of the large diameter cylindrical portion13bis regulated to a predetermined dimension Lb and the other axial radially outer chamfered portion2b2is simultaneously formed at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion13bby the chamfer forming portion26a3b. Further, the punching punch26cis displaced toward one axial side so that a portion located on the radial inside in relation to the inner peripheral surface of the small diameter cylindrical portion13cin the side plate portion13ais punched out and removed. Accordingly, the first intermediate material25is obtained.

In the next fifth step, the first intermediate material25is subjected to a small diameter side dimension regulating process of regulating the axial dimension of the small diameter cylindrical portion25bto a predetermined dimension Ls (seeFIG.14) and forming the radially inner chamfered portions3b1and3b2at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion25bto obtain a second intermediate material27shown inFIG.12(E). The second intermediate material (second piece)27includes a large diameter cylindrical portion (third ring portion)27aon one axial side, a small diameter cylindrical portion (fourth ring portion)27bon the other axial side, and a connection plate portion27cconnecting the other axial end portion of the large diameter cylindrical portion27ato the other axial end portion of the small diameter cylindrical portion27b. The small diameter cylindrical portion27bincludes the radially inner chamfered portions3b1and3b2formed at the connection portion between the inner peripheral surface and both axial end surfaces and the large diameter cylindrical portion27aincludes the other axial radially outer chamfered portion2b2formed at the connection portion between the outer peripheral surface and the other axial end surface.

Additionally, in this example, in the fifth step, the large diameter cylindrical portion25aand the connection plate portion25cof the first intermediate material25are not subjected to plastic working.

The fifth step is performed by using a press working device28shown inFIG.14. The press working device28includes a die28a, an inner pressing punch (second member)28b, an outer pressing punch (first member)28c, a presser punch28d, an inner counter punch (fourth member)28e, and an outer counter punch (third member)28f.

The die28ahas a stepped cylindrical inner peripheral surface formed by connecting a large diameter portion28a1on one axial side (the upper side ofFIG.14) to a small diameter portion28a2on the other axial side (the lower side ofFIG.14) with a stepped surface28a3facing one axial side.

The inner pressing punch28bhas a cylindrical shape and is supported at the center portion of the large diameter portion28a1of the die28ato be axially displaceable with respect to the support table (not shown) of the press working device28. The inner pressing punch28bincludes a chamfer forming portion (inclined surface)28b1formed at the tip portion (the other axial end portion) to have a linear generatrix shape.

The outer pressing punch28chas a cylindrical shape and is supported around the inner pressing punch28bto be axially displaceable with respect to the support table.

The presser punch28dhas a cylindrical shape and is supported around the outer pressing punch28cto be axially displaceable with respect to the support table.

The inner counter punch28ehas a columnar shape and is supported at the center portion of the small diameter portion28a2of the die28ato be axially displaceable with respect to the support table (not shown) of the press working device28. The inner counter punch28eincludes a chamfer forming portion (inclined surface)28e1formed on the outer peripheral surface of the tip portion (one axial end portion). The chamfer forming portion28e1is formed as a conical surface which is inclined toward the other axial side as it goes toward the radial outside.

The outer counter punch28fhas a cylindrical shape and is supported to be axially displaceable with respect to the support table. The outer counter punch28fis inserted between the small diameter portion28a2of the die28aand the outer peripheral surface of the inner counter punch28esubstantially without a gap.

In order to obtain the second intermediate material27by performing a small diameter side dimension regulating process on the first intermediate material25using the press working device28, first, the other axial surface of the connection plate portion25cof the first intermediate material25is placed on the stepped surface28a3of the die28a. Then, the presser punch28dis displaced toward the other axial side so that the presser punch28dpresses one axial end surface of the large diameter cylindrical portion25aof the first intermediate material25(the large diameter cylindrical portion25ais sandwiched between the stepped surface28a3of the die28aand the presser punch28din the axial direction).

In this state, the inner pressing punch28band the outer pressing punch28care displaced toward the other axial side and the inner counter punch28eand the outer counter punch28fare displaced toward one axial side. Then, the small diameter cylindrical portion25bof the first intermediate material25is axially crushed between the group of the inner pressing punch28band the outer pressing punch28cand the group of the inner counter punch28eand the outer counter punch28f. Accordingly, the axial dimension of the small diameter cylindrical portion25bis regulated to a predetermined dimension Ls and the radially inner chamfered portions3b1and3b2are simultaneously formed at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion25bby the chamfer forming portion28e1of the inner counter punch28eand the chamfer forming portion28b1of the inner pressing punch28b. As described above, the second intermediate material27is obtained.

In the next sixth step, the second intermediate material27is subjected to a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion27bto obtain the third intermediate material20shown inFIG.12(F). The third intermediate material20has the same shape as the shape of the third intermediate material20after the sixth step of the first example is completed.

Additionally, in this example, in the sixth step, a portion other than the inner peripheral surface of the small diameter cylindrical portion27b, that is, the outer peripheral surfaces of the large diameter cylindrical portion27a, the connection plate portion27c, and the small diameter cylindrical portion27bof the second intermediate material27are not subjected to plastic working.

The sixth step is performed by using a press working device29shown inFIG.15. The press working device29includes a die29a, a sleeve29b, and a shaving cutter29c.

The die29aincludes a cylindrical inner peripheral surface.

The sleeve29bis fitted into the axially outer portion (the lower portion ofFIG.15) of the die29asubstantially without a gap.

The shaving cutter29chas a columnar shape and is supported at the center portion of the die29ato be axially displaceable with respect to the support table (not shown) of the press working device29. The shaving cutter29cincludes a blade portion29c1which is formed at the radially outer edge of the tip portion (the other axial end portion) to perform a shaving process of slightly scraping the surface of the inner peripheral surface of the small diameter cylindrical portion27bof the second intermediate material27to be smooth on the inner peripheral surface.

In order to obtain the third intermediate material20by performing a punching process on the second intermediate material27using the press working device29, the other axial end surface of the large diameter cylindrical portion27aof the second intermediate material27and the other axial surface of the connection plate portion27care first placed on the end surface of the sleeve29bon one axial side (the upper side ofFIG.15). In this state, the shaving cutter29cis displaced toward the other axial side so that the blade portion29c1slightly scrapes (shaves) the inner peripheral surface of the small diameter cylindrical portion27bto be smooth. Accordingly, the third intermediate material20is obtained.

In the seventh step, the third intermediate material20obtained as described above is subjected to a separating process of separating the large diameter cylindrical portion20a(and the connection plate portion20c) and the small diameter cylindrical portion20bfrom each other to obtain the preliminary large diameter cylindrical member22and the small diameter cylindrical member (second ring element)12shown inFIG.12(G). Further, in the eighth step, a large diameter side shaving process of shaving the inner peripheral surface of the preliminary large diameter cylindrical member22to remove an extra thickness and a second large diameter side chamfering process of forming one axial radially outer chamfered portion2b1at the connection portion between the inner peripheral surface and one axial end surface of the large diameter cylindrical portion22aare performed to obtain the large diameter cylindrical member (first ring element)11shown inFIG.12(H). The configurations, operations, and effects of the other parts are the same as those of the first example.

Third Example

A third example of the present invention will be described with reference toFIGS.16to19. A first step to a third step and an eighth step in a manufacturing method of this example are the same as the first step to the third step and the eighth step of the first example. Hereinafter, a fourth step to a seventh step in the manufacturing method of this example will be described.

In the fourth step, the preliminary intermediate material13shown inFIG.16(C)is subjected to a punching process of punching out and removing a portion located on the radial inside in relation to the inner peripheral surface of the small diameter cylindrical portion13cin the side plate portion13ato obtain a first intermediate material30shown inFIG.16(D). The first intermediate material (first piece)30includes a large diameter cylindrical portion (first ring portion)30aon one axial side (the upper side ofFIG.16(D)), a small diameter cylindrical portion (second ring portion)30bon the other axial side (the lower side ofFIG.16(D)), and a connection plate portion30cconnecting the other axial end portion of the large diameter cylindrical portion30ato one axial end portion of the small diameter cylindrical portion30b.

The fourth step is performed by using a press working device31shown inFIG.17. The press working device31includes a die31a, a presser punch31b, and a punching punch31c.

The die31aincludes a cylindrical inner peripheral surface.

The presser punch31bhas a stepped cylindrical shape. That is, the presser punch31bincludes a stepped cylindrical outer peripheral surface formed by connecting a small diameter portion31b1on the other axial side (the lower side ofFIG.17) and a large diameter portion31b2on one axial side (the upper side ofFIG.17) with a stepped surface31b3facing the other axial side.

The punching punch31chas a columnar shape.

In order to obtain the first intermediate material30by performing a punching process on the preliminary intermediate material13using the press working device31, first, the large diameter cylindrical portion13bof the preliminary intermediate material13is fitted and held in the die31awithout rattling and the other axial end surface of the small diameter portion31b1of the presser punch31bis allowed to contact or face one axial surface of the side plate portion13ato regulate the displacement of the preliminary intermediate material13toward one axial side. In this state, the punching punch31cis displaced toward one axial side so that a portion located on the radial inside in relation to the inner peripheral surface of the small diameter cylindrical portion13cin the side plate portion13ais punched out and removed. Accordingly, the first intermediate material30is obtained.

The next fifth step is the same as the fifth step of the second example. That is, in the fifth step, the first intermediate material30is subjected to a small diameter side dimension regulating process of regulating the axial dimension of the small diameter cylindrical portion30bto a predetermined dimension Ls and forming the radially inner chamfered portions3b1and3b2at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion30bto obtain a second intermediate material32shown inFIG.16(E). The second intermediate material (first piece, second piece)32includes a large diameter cylindrical portion (first ring portion, third ring portion)32aon one axial side, a small diameter cylindrical portion (second ring portion, fourth ring portion)32bon the other axial side, and a connection plate portion32cconnecting the other axial end portion of the large diameter cylindrical portion32ato the other axial end portion of the small diameter cylindrical portion32b. The small diameter cylindrical portion32bincludes the radially inner chamfered portions3b1and3b2formed at the connection portion between the inner peripheral surface and both axial end surfaces and includes an extra thick portion32b1protruding from the radially intermediate portion toward the radial inside.

The press working device used in the fifth step of this example has substantially the same structure as that of the press working device28(seeFIG.14) used in the fifth step of the second example. Further, since the procedure of processing the first intermediate material30into the second intermediate material32by the press working device is basically the same as the procedure of processing the first intermediate material25into the second intermediate material27in the fifth step of the second example, the detailed description will be omitted.

In the next sixth step, the second intermediate material32is subjected to a large diameter side dimension regulating process of regulating the axial dimension of the large diameter cylindrical portion32ato a predetermined dimension Lb (seeFIG.18) and a first large diameter side chamfering process of forming the other axial radially outer chamfered portion2b2at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion32a. Further, in this example, an ironing process of gathering an extra thickness by ironing the inner peripheral surface of the small diameter cylindrical portion32bis performed at the same time. Accordingly, a third intermediate material33shown inFIG.16(F)is obtained.

The third intermediate material (second piece)33includes a large diameter cylindrical portion (third ring portion)33aon one axial side (the upper side ofFIG.16(F)), a small diameter cylindrical portion (fourth ring portion)33bon the other axial side (the lower side ofFIG.16(F)), a connection plate portion33cconnecting the other axial end portion of the large diameter cylindrical portion33ato the other axial end portion of the small diameter cylindrical portion33b, and an inward flange-shaped extra thick portion33dprotruding radially inward from the axially intermediate portion of the small diameter cylindrical portion33b. The large diameter cylindrical portion33aincludes the other axial radially outer chamfered portion2b2formed at the connection portion between the outer peripheral surface and the other axial end surface and the small diameter cylindrical portion33bincludes the radially inner chamfered portions3b1and3b2formed at the connection portion between the inner peripheral surface and both axial end surfaces.

The sixth step is performed by using a press working device34shown inFIG.18. The press working device34includes a die34a, a mandrel (fourth member)34b, a sleeve (third member)34c, a pressing punch (first member)34d, and an ironing punch (second member)34e.

The die34aincludes a stepped cylindrical inner peripheral surface which includes a large diameter portion34a1on one axial side (the upper side ofFIG.18), a small diameter portion34a2on the other axial side (the lower side ofFIG.18), and a conical chamfer forming portion (inclined surface)34a3connecting the other axial end portion of the large diameter portion34a1to one axial end portion of the small diameter portion34a2.

The mandrel34bincludes a stepped cylindrical outer peripheral surface which includes a small diameter portion34b1on one axial side, a large diameter portion34b2on the other axial side, and a stepped surface (inclined surface)34b3connecting the other axial end portion of the small diameter portion34b1to one axial end portion of the large diameter portion34b2. The stepped surface34b3is formed as a conical surface inclined toward the other axial side as it goes toward the radial outside.

The sleeve34cis inserted between the small diameter portion34a2of the die34aand the large diameter portion34b2of the mandrel34bsubstantially without a gap.

The pressing punch34dhas a cylindrical shape and is supported to be axially displaceable with respect to the support table (not shown) of the press working device34.

The ironing punch34ehas an outer diameter dimension substantially equal to the inner diameter dimension of the small diameter cylindrical portion33bof the third intermediate material33to be obtained and is disposed inside the pressing punch34dto be axially displaceable with respect to the pressing punch34d.

In order to obtain the third intermediate material33by performing a large diameter side dimension regulating process, a first large diameter side chamfering process, and an ironing process on the second intermediate material32using the press working device34, first, the radially outer portion of the other axial surface of the connection plate portion32cof the second intermediate material32is placed on the chamfer forming portion34a3of the die34aand one axial end surface of the sleeve34cand the small diameter cylindrical portion32bis inserted between the inner peripheral surface of the sleeve34cand the small diameter portion34b1of the mandrel34b.

In this state, the pressing punch34dand the ironing punch34eare displaced toward the other axial side. Accordingly, the tip portion of the ironing punch34eis pressed from one axial side toward the radial inside of the one axial portion of the small diameter cylindrical portion32bof the second intermediate material32so that the one axial portion of the inner peripheral surface of the small diameter cylindrical portion32bis ironed by the ironing punch34e. At the same time, the small diameter portion34b1of the mandrel34bis pressed from the other axial side toward the radial inside of the axially outer portion of the small diameter cylindrical portion32b(the axially outer portion of the small diameter cylindrical portion32bis pressed between the inner peripheral surface of the sleeve34cand the small diameter portion34b1of the mandrel34b) so that the axially outer portion of the inner peripheral surface of the small diameter cylindrical portion32bis ironed by the mandrel34b. Accordingly, the inward flange-shaped extra thick portion33dis formed to protrude from the axially intermediate portion of the small diameter cylindrical portion33btoward the radial inside.

Further, the large diameter cylindrical portion32aof the second intermediate material32is axially crushed between the tip surface of the pressing punch34dand the group of the chamfer forming portion34a3of the die34aand one axial end surface of the sleeve34c. Accordingly, the axial dimension of the large diameter cylindrical portion32ais regulated to a predetermined dimension Lb and the radially outer chamfered portion2b2is simultaneously formed at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion32aby the chamfer forming portion34a3. As described above, a third intermediate material33is obtained.

In the next seventh step, the third intermediate material33is subjected to a separating process of separating the large diameter cylindrical portion33a(and the connection plate portion33c) and the small diameter cylindrical portion33bfrom each other and a small diameter side shaving process of removing the extra thick portion33dexisting on the radial inside of the small diameter cylindrical portion33bto obtain the preliminary large diameter cylindrical member22and the small diameter cylindrical member12shown inFIG.16(G). Additionally, in the example shown in the drawings, the seventh step is performed while the direction with respect to the axial direction of the third intermediate material33before processing in the seventh step is reversed (rotated by 180°) from the direction with respect to the axial direction of the third intermediate material33after processing in the sixth step.

The seventh step is performed by using a press working device35shown inFIG.19. The press working device35includes a die35a, a cylindrical presser punch35b, a cylindrical punching punch35c, and a columnar shaving cutter35d. The die35aincludes a stepped cylindrical inner peripheral surface formed by connecting a small diameter portion35a1on one axial side (the lower side ofFIG.19) to a large diameter portion35a2on the other axial side (the upper side ofFIG.19) with a stepped surface35a3facing the other axial side.

In order to obtain the preliminary large diameter cylindrical member22and the small diameter cylindrical member12by performing a separating process and a small diameter side shaving process on the third intermediate material33using the press working device35, first, one axial end surface of the large diameter cylindrical portion33aof the third intermediate material33is placed on the stepped surface35a3of the die35a. Next, the presser punch35bis displaced toward one axial side so that the tip surface (one axial end surface) of the presser punch35bpresses the other axial surface of the connection plate portion33cof the third intermediate material33.

In this state, the punching punch35cis displaced toward the other axial side so that the small diameter cylindrical portion33bof the third intermediate material33is punched out and is separated from the large diameter cylindrical portion33aand the connection plate portion33c. The shaving cutter35dis displaced toward one axial side at the same time when the small diameter cylindrical portion33bis punched by the punching punch35cor before and after the small diameter cylindrical portion33bis punched, the shaving cutter35dscrapes and removes the inward flange-shaped extra thick portion33dprotruding from the axially intermediate portion of the small diameter cylindrical portion33btoward the radial inside. As described above, the preliminary large diameter cylindrical member22and the small diameter cylindrical member (second ring element)12are obtained and the small diameter cylindrical member12among them is sent to the post-treatment step. On the other hand, in the subsequent eighth step, the preliminary large diameter cylindrical member22is subjected to a large diameter side shaving process and a second large diameter side chamfering process to obtain the large diameter cylindrical member (first ring element)11shown inFIG.16(H). The configurations, operations, and effects of the other parts are the same as those of the first example.

Fourth Example

A fourth example of the present invention will be described with reference toFIGS.20and21. A first step to a fifth step in a manufacturing method of this example are the same as the first step to the fifth step of the third example. Further, a seventh step and an eighth step in the manufacturing method of this example are the same as the seventh step and the eighth step of the first example. Here, a sixth step in the manufacturing method of this example will be described below.

In the sixth step of this example, the second intermediate material32shown inFIG.20(E)is simultaneously subjected to three processes of a large diameter side dimension regulating process of regulating the axial dimension of the large diameter cylindrical portion32ato a predetermined dimension Lb (seeFIG.21), a first large diameter side chamfering process of forming the other axial radially outer chamfered portion2b2at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion32a, and a small diameter side shaving process of removing an extra thickness existing on the radial inside of the small diameter cylindrical portion33b. Accordingly, the third intermediate material20shown inFIG.20(F)is obtained.

The sixth step is performed by using a press working device36shown inFIG.21. The press working device36includes a die36a, a cylindrical presser punch36b, a cylindrical pressing punch36cdisposed around the presser punch36b, a columnar shaving cutter36ddisposed in the presser punch36b, and a cylindrical counter punch36e.

The die36aincludes a stepped cylindrical inner peripheral surface formed by connecting a large diameter portion36a1on one axial side (the upper side ofFIG.21) to a small diameter portion36a2on the other axial side (the lower side ofFIG.21) with a stepped surface36a3facing one axial side. The stepped surface36a3includes a conical chamfer forming portion36a3aformed at the radially outer portion to be inclined toward one axial side as it goes toward the radial outside.

In order to obtain the third intermediate material20by performing a large diameter side dimension regulating process, a first large diameter side chamfering process, and a small diameter side shaving process on the second intermediate material32using the press working device36, first, the other axial surface of the connection plate portion32cof the second intermediate material32is placed on the stepped surface36a3of the die36a. Next, the presser punch36bis displaced toward the other axial side so that the tip surface (the other axial end surface) of the presser punch36bpresses the other axial surface of the connection plate portion32cof the second intermediate material32.

In this state, one axial end surface of the large diameter cylindrical portion32aof the second intermediate material32is pressed toward the other axial side by the pressing punch36cso that the large diameter cylindrical portion32ais axially crushed between the tip surface of the pressing punch36cand the stepped surface36a3of the die36a. Accordingly, the axial dimension of the large diameter cylindrical portion32ais regulated to a predetermined dimension Lb and the radially outer chamfered portion2b2is formed at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion32aby the chamfer forming portion36a3a.

The inner peripheral surface of the small diameter cylindrical portion32bof the second intermediate material32is shaved by the shaving cutter36dat the same time as pressing one axial end surface of the large diameter cylindrical portion32aor before and after pressing one axial end surface of the large diameter cylindrical portion32aby the pressing punch36c. As described above, the third intermediate material20is obtained. The configurations, operations, and effects of the other parts are the same as those of the first example and the third example.

Fifth Example

A fifth example of the present invention will be described with reference to parts (A) to (H) ofFIG.22. A first step to a fourth step, a seventh step, and an eighth step in a manufacturing method of this example are the same as the first step to the fourth step, the seventh step, and the eighth step of the first example. In other words, a fifth step and a sixth step of the manufacturing method of this example are different from those of the manufacturing method of the first example.

In the fifth step of this example, the first intermediate material16is subjected to a punching process of punching out and removing the partition wall portion16dand a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion16b. Accordingly, a second intermediate material37shown inFIG.22(E)is obtained. The second intermediate material37includes a large diameter cylindrical portion37aon one axial side, a small diameter cylindrical portion37bon the other axial side, and a connection plate portion37cconnecting the other axial end portion of the large diameter cylindrical portion37ato one axial end portion of the small diameter cylindrical portion37b.

In the next sixth step, the second intermediate material37is simultaneously subjected to a large diameter side dimension regulating process of regulating the axial dimension of the large diameter cylindrical portion37ato a predetermined dimension Lb and a first large diameter side chamfering process of forming the radially outer chamfered portion2b2at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion37a. Accordingly, the third intermediate material20shown inFIG.22(F)is obtained. The configurations, operations, and effects of the other parts are the same as those of the first example.

Sixth Example

A sixth example of the present invention will be described with reference to parts (A) to (G) ofFIG.23. In this example, the total number of steps of manufacturing the single columnar material10into the large diameter cylindrical member (first ring element)11and the small diameter cylindrical member (second ring element)12are seven steps. A first step to a fifth step and a seventh step in a manufacturing method of this example are the same as the first step to the fifth step and the eighth step of the first example. That is, in the manufacturing method of this example, the sixth step and the seventh step of the first example are performed as one step in the sixth step.

Specifically, in the sixth step of this example, the second intermediate material18is simultaneously subjected to three processes of a separating process of separating the large diameter cylindrical portion18aand the small diameter cylindrical portion18bfrom each other, a punching process of punching out and removing the partition wall portion18d, and a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion18bto remove an extra thickness to obtain the preliminary large diameter cylindrical member22and the small diameter cylindrical member12shown inFIG.23(F). The configurations, operations, and effects of the other parts are the same as those of the first example.

Seventh Example

A seventh example of the present invention will be described with reference to parts (A) to (H) ofFIG.24. A first step to a third step, a seventh step, and an eighth step in a manufacturing method of this example are the same as the first step to the third step, the seventh step, and the eighth step of the first example. Further, a sixth step in the manufacturing method of this example is the same as the sixth step of the fifth example.

In the fourth step of this example, the preliminary intermediate material13is subjected to a punching process of punching out and removing a portion located on the radial inside in relation to the inner peripheral surface of the small diameter cylindrical portion13cof the side plate portion13aand a small diameter side dimension regulating process of regulating the axial dimension of the small diameter cylindrical portion13cto a predetermined dimension Ls and forming the radially inner chamfered portions3b1and3b2at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion13c. Accordingly, a first intermediate material38shown inFIG.24(D)is obtained.

The first intermediate material (second piece)38includes a large diameter cylindrical portion (third ring portion)38aon one axial side, a small diameter cylindrical portion (fourth ring portion)38bon the other axial side, and a connection plate portion38cconnecting the other axial end portion of the large diameter cylindrical portion38ato one axial end portion of the small diameter cylindrical portion38b. The small diameter cylindrical portion38bincludes the radially inner chamfered portions3b1and3b2formed at the connection portion between the inner peripheral surface and both axial end surfaces.

In the next fifth step, the first intermediate material38is subjected to a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion38bto obtain the second intermediate material37shown inFIG.24(E). The configurations, operations, and effects of the other parts are the same as those of the first example and the fifth example.

Eighth Example

An eighth example of the present invention will be described with reference to parts (A) to (H) ofFIG.25. A first step to a third step, a seventh step, and an eighth step in a manufacturing method of this example are the same as the first step to the third step, the seventh step, and the eighth step of the first example.

In the fourth step of this example, the preliminary intermediate material13is subjected to a large diameter side dimension regulating process of regulating the axial dimension of the large diameter cylindrical portion13bto a predetermined dimension Lb and a first large diameter side chamfering process of forming the radially outer chamfered portion2b2at the connection portion between the outer peripheral surface and the other axial end surface of the large diameter cylindrical portion13b. Accordingly, a first intermediate material39shown inFIG.25(D)is obtained.

The first intermediate material (first piece)39includes a disc-shaped side plate portion39a, a large diameter cylindrical portion (first ring portion)39bprotruding from the radially outer portion of one axial surface (the upper surface ofFIG.25(D)) of the side plate portion39atoward one axial side, and a small diameter cylindrical portion (second ring portion)39cprotruding from the radially intermediate portion of the other axial surface (the lower surface ofFIG.25(D)) of the side plate portion39atoward the other axial side. The large diameter cylindrical portion39bincludes the radially outer chamfered portion2b2formed at the connection portion between the outer peripheral surface and the other axial end surface.

In the next fifth step, the first intermediate material39is subjected to a small diameter side dimension regulating process of regulating the axial dimension of the small diameter cylindrical portion39cto a predetermined dimension Ls and forming the radially inner chamfered portions3b1and3b2at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion39cto obtain a second intermediate material40shown inFIG.25(E).

The second intermediate material (second piece)40includes a large diameter cylindrical portion (third ring portion)40aon one axial side, a small diameter cylindrical portion (fourth ring portion)40bon the other axial side, a connection plate portion40cconnecting the other axial end portion of the large diameter cylindrical portion40ato the other axial end portion of the small diameter cylindrical portion40b, and a partition wall portion40dformed at a portion located on one axial side and the radial inside of the small diameter cylindrical portion40b. The small diameter cylindrical portion40bincludes the radially inner chamfered portions3b1and3b2formed at the connection portion between the inner peripheral surface and both axial end surfaces.

In the next sixth step, the second intermediate material40is subjected to a punching process of punching out and removing the partition wall portion40dand a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion40b. Accordingly, the third intermediate material20shown inFIG.25(F)is obtained. The configurations, operations, and effects of the other parts are the same as those of the first example.

Ninth Example

A ninth example of the present invention will be described with reference to parts (A) to (G) ofFIG.26. In this example, the total number of steps of manufacturing the large diameter cylindrical member (first ring element)11and the small diameter cylindrical member (second ring element)12from the single columnar material10are seven steps. A first step to a fifth step and a seventh step in a manufacturing method of this example are the same as the first step to the fifth step and the eighth step of the eighth example. That is, in the manufacturing method of this example, the sixth step and the seventh step of the eighth example are performed as one step in the sixth step.

Specifically, in the sixth step of this example, the second intermediate material40is simultaneously subjected to three processes of a separating process of separating the large diameter cylindrical portion40aand the small diameter cylindrical portion40bfrom each other, a punching process of punching out and removing the partition wall portion40d, and a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion40bto remove an extra thickness. Accordingly, the preliminary large diameter cylindrical member22and the small diameter cylindrical member12shown inFIG.26(F)are obtained. The configurations, operations, and effects of the other parts are the same as those of the first example and the eighth example.

Tenth Example

A tenth example of the present invention will be described with reference to parts (A) to (I) ofFIG.27. In this example, the total number of steps of manufacturing the large diameter cylindrical member (first ring element)11and the small diameter cylindrical member (second ring element)12from the single columnar material10are nine steps. A first step to a fifth step, an eighth step, and a ninth step in a manufacturing method of this example are the same as the first step to the fifth step, the seventh step, and the eighth step of the first example. That is, in this example, the punching process and the small diameter side shaving process which are performed at the same time in the sixth step of the first example are respectively performed in different steps.

Specifically, in the sixth step of this example, the second intermediate material18is subjected to a punching process of punching out and removing the partition wall portion18dto obtain a third preliminary intermediate material41shown inFIG.27(F). The third preliminary intermediate material41includes a large diameter cylindrical portion41aon one axial side, a small diameter cylindrical portion41bon the other axial side, and a connection plate portion41cconnecting the other axial end portion of the large diameter cylindrical portion41ato one axial end portion of the small diameter cylindrical portion41b.

In the next seventh step, the third preliminary intermediate material41is subjected to a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion41bto remove an extra thickness. Accordingly, the third intermediate material20shown inFIG.27(G)is obtained. The configurations, operations, and effects of the other parts are the same as those of the first example.

Eleventh Example

An eleventh example of the present invention will be described with reference to parts (A) to (J) ofFIG.28. In this example, the total number of steps of manufacturing the large diameter cylindrical member (first ring element)11and the small diameter cylindrical member (second ring element)12from the single columnar material10are ten steps. A first step to a fourth step in a manufacturing method of this example are the same as the first step to the fourth step of the first example.

In the fifth step of this example, the first intermediate material16is subjected to a punching process of punching out and removing the partition wall portion16dto obtain a second intermediate material42shown inFIG.28(E). The second intermediate material42includes a large diameter cylindrical portion42aon one axial side, a small diameter cylindrical portion42bon the other axial side, and a connection plate portion42cconnecting the other axial end portion of the large diameter cylindrical portion42ato one axial end portion of the small diameter cylindrical portion42b.

In the next sixth step, the second intermediate material42is subjected to a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion42bto obtain a third intermediate material43shown inFIG.28(F). The third intermediate material43includes a large diameter cylindrical portion43aon one axial side, a small diameter cylindrical portion43bon the other axial side, and a connection plate portion43cconnecting the other axial end portion of the large diameter cylindrical portion43ato one axial end portion of the small diameter cylindrical portion42b.

In the next seventh step, the third intermediate material43is subjected to a separating process of separating the large diameter cylindrical portion43a(and the connection plate portion43c) and the small diameter cylindrical portion43bfrom each other to obtain a first preliminary large diameter cylindrical member44and the small diameter cylindrical member12shown inFIG.28(G). The first preliminary large diameter cylindrical member44includes a large diameter cylindrical portion44aand an inward flange portion44bbent from the other axial end portion of the large diameter cylindrical portion44atoward the radial inside.

In the next eighth step, the first preliminary large diameter cylindrical member44is simultaneously subjected to a large diameter side dimension regulating process of regulating the axial dimension to a predetermined dimension Lb, a first large diameter side chamfering process of forming the radially outer chamfered portion at the connection portion between the outer peripheral surface and the other axial end surface, and a second large diameter side chamfering process of forming the radially outer chamfered portion at the connection portion between the outer peripheral surface and one axial end surface. Accordingly, as shown inFIG.28(H), a second preliminary large diameter cylindrical member45including a large diameter cylindrical portion45aand an inward flange portion45bbent from the other axial end portion of the large diameter cylindrical portion45atoward the radial inside is obtained. The large diameter cylindrical portion45aincludes the radially outer chamfered portions2b1and2b2which are formed at the connection portion between the outer peripheral surface and both axial end surfaces.

In the next ninth step, the second preliminary large diameter cylindrical member45is subjected to a punching process to remove the inward flange portion45bfrom the second preliminary large diameter cylindrical member45. Accordingly, a cylindrical third preliminary large diameter cylindrical member46shown inFIG.28(I)is obtained.

Finally, in the tenth step, the third preliminary large diameter cylindrical member46is subjected to a large diameter side shaving process to obtain a large diameter cylindrical member (first ring element)11shown inFIG.28(J). The configurations, operations, and effects of the other parts are the same as those of the first example.

Here, in the conventional method described in Japanese Patent Application, Publication No. 2009-269082, since the end portion on one axial side (the upper side of parts (A) and (B) ofFIG.31) of the cavity8dof the second press working device8is opened, it is difficult to regulate the axial dimension of the large diameter cylindrical portion9bof the second intermediate material9with high accuracy. Thus, since the axial dimension of the large diameter cylindrical member having a large diameter dimension in the pair of cylindrical members becomes largely uneven, the amount of cutting or grinding in the post-treatment increases. As a result, there is a possibility that the cost increases.

In the cylindrical member manufacturing method, it is possible to reduce the amount of cutting and/or grinding in the post-treatment by providing the step of regulating the axial dimensions of the large diameter cylindrical member and the small diameter cylindrical member in the process of manufacturing the large diameter cylindrical member and the small diameter cylindrical member from the columnar material (billet) by press working. Further, it is possible to reduce the amount of cutting and/or grinding in the post-treatment step while suppressing an increase in press load or the number of steps by regulating the axial dimension of the small diameter cylindrical member and simultaneously forming the chamfered portion at the connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical member by press working.

In an embodiment, a cylindrical member manufacturing method manufactures a large diameter cylindrical member including a pair of radially outer chamfered portions formed at a connection portion between an outer peripheral surface and both axial end surfaces and a small diameter cylindrical member including a pair of radially inner chamfered portions at a connection portion between an inner peripheral surface and both axial end surfaces from a single columnar material (billet) by press working.

First, the columnar material is sequentially subjected to an upsetting process and a front-rear extruding process to form a circular flat side plate portion, a large diameter cylindrical portion protruding from a radially outer portion of one axial surface of the side plate portion toward one axial side, and a small diameter cylindrical portion protruding from a radially intermediate portion of the other axial surface of the side plate portion toward the other axial side.

Then, the large diameter cylindrical member and the small diameter cylindrical member are obtained by performing a punching process of punching out and removing a portion located on the radial inside in relation to an inner peripheral surface of the small diameter cylindrical portion in the side plate portion, a small diameter side dimension regulating process of regulating an axial dimension of the small diameter cylindrical portion to a predetermined dimension and forming a pair of radially inner chamfered portions at a connection portion between the inner peripheral surface and both axial end surfaces of the small diameter cylindrical portion, a small diameter side shaving process of shaving the inner peripheral surface of the small diameter cylindrical portion, a separating process of separating the large diameter cylindrical portion and the small diameter cylindrical portion from each other to obtain a preliminary large diameter cylindrical member including the large diameter cylindrical portion and an inward flange portion bent from the other axial end portion of the large diameter cylindrical portion toward the radial inside and the small diameter cylindrical member, a large diameter side dimension regulating process of regulating an axial dimension of the large diameter cylindrical portion or the preliminary large diameter cylindrical member to a predetermined dimension, a first large diameter side chamfering process of forming the other axial radially outer chamfered portion of the pair of radially outer chamfered portions at a connection portion between an outer peripheral surface and the other axial end surface of the large diameter cylindrical portion or the preliminary large diameter cylindrical member, a second large diameter side chamfering process of forming one axial radially outer chamfered portion of the pair of radially outer chamfered portions at a connection portion between the outer peripheral surface and one axial end surface of the large diameter cylindrical portion or the preliminary large diameter cylindrical member, and a large diameter side shaving process of shaving an inner peripheral surface of the preliminary large diameter cylindrical member.

The punching process, the small diameter side dimension regulating process, the small diameter side shaving process, the separating process, the large diameter side dimension regulating process, the first large diameter side chamfering process, the second large diameter side chamfering process, and the large diameter side shaving process can be performed in any order or in the same step as long as there is no contradiction. These processes can be performed in any order or in combination of two or more processes at the same time as long as there is no contradiction.

Specifically, the appropriate order and combination are determined by experiments and simulations depending on the material of the columnar material, the shape and size of the large diameter cylindrical member and the small diameter cylindrical member, the pressurizing capacity of the press working device to be used, the durability of the die and the tool, and the like.

However, the punching process needs to be performed at the same time as the separating process or before the separating process. Further, the small diameter side dimension regulating process needs to be performed before the separating process and needs to be performed at the same time as the punching process or before the punching process.

Further, the small diameter side shaving process is preferably performed at the same time as the punching process or after the punching process.

However, when the small diameter side shaving process and the punching process are performed at the same time, a portion located on the radial inside in relation to the inner peripheral surface of the small diameter cylindrical portion in the side plate portion is punched out by the punching process and the inner peripheral surface of the punched portion is subjected to the shaving process.

The large diameter side shaving process can be performed after the separating process.

The small diameter side shaving process can be performed at the same time as the punching process or after the punching process.

The large diameter side dimension regulating process and the first large diameter side chamfering process can be performed in the same step.

The second large diameter side chamfering process and the large diameter side shaving process can be performed in the same step.

The punching process and the small diameter side shaving process can be performed in the same step.

The small diameter side shaving process and the large diameter side dimension regulating process can be performed in the same step.

The punching process and the separating process can be performed in the same step.

The punching process and the small diameter side dimension regulating process can be performed in the same step.

The punching process and the large diameter side dimension regulating process can be performed in the same step.

Before the small diameter side shaving process, the inner peripheral surface of the small diameter cylindrical portion is subjected to an ironing process to gather an extra thickness.

Additionally, in the present specification, performing a plurality of processes at the same time means that a plurality of processes do not have to be performed completely at the same time in terms of time and a plurality of processes are performed in the same step (so-called one chuck) without separating a workpiece from the press working device.

In the cylindrical member manufacturing method of an embodiment, the total number of steps including a step of cutting a long wire to a predetermined length to obtain the columnar material, a step of performing an upsetting process on the columnar material to obtain a thick disc-shaped or beer barrel-shaped preliminary material, and a step of performing the front-rear extruding process on the preliminary material to obtain the preliminary intermediate material is preferably10steps or less and more preferably8steps or less.

In an embodiment, a radial rolling bearing manufacturing method is used for a radial rolling hearing including an outer race which has an outer race track formed on an inner peripheral surface and includes a pair of radially outer chamfered portions formed at a connection portion between an outer peripheral surface and both axial end surfaces, an inner race which has an inner race track formed on an outer peripheral surface and includes a pair of radially inner chamfered portions formed at a connection portion between an inner peripheral surface and both axial end surfaces, and a plurality of rolling elements which are arranged between the outer race track and the inner race track in a rollable manner.

In the manufacturing method, after the large diameter cylindrical member and the small diameter cylindrical member are manufactured by the cylindrical member manufacturing method, the outer race track is formed on the inner peripheral surface of the large diameter cylindrical member to obtain the outer race and the inner race track is formed on the outer peripheral surface of the small diameter cylindrical member to obtain the inner race.

In an embodiment, a sliding bearing manufacturing method manufactures a pair of sliding bearings having different diameter dimensions from a single columnar material.

The manufacturing method includes a step of obtaining the large diameter cylindrical member and the small diameter cylindrical member by the cylindrical member manufacturing method. Additionally, in the manufacturing method, a pair of sliding bearings having different diameter dimensions is manufactured by performing a finishing process such as a grinding process on the surfaces of the large diameter cylindrical members and the small diameter cylindrical member if necessary after the large diameter cylindrical member and the small diameter cylindrical member are obtained.

In an embodiment, an outer race has an outer race track formed on an inner peripheral surface and includes a pair of radially outer chamfered portions formed at a connection portion between an outer peripheral surface and both axial end surfaces.

In this outer race, the entire outer peripheral surface including the pair of radially outer chamfered portions is formed as a forged surface that has not been finished by a grinding process or the like. In this case, the metal flow (fiber flow, forging streamline) is continuous along each of the pair of radially outer chamfered portions in the vicinity of each surface of the pair of radially outer chamfered portions.

In an embodiment, an outer race can include a radially outer chamfered portion formed at a connection portion between an outer peripheral surface and both axial end surfaces. In this case, the metal flow inside the outer race is continuous along the radially outer chamfered portion in the vicinity of the surface of the radially outer chamfered portion.

The metal flow can have a curved portion which is formed at a portion axially deviated from the outer race track in the axial direction to be curved toward the radial outside and to be changed (curved) in the direction of folding back toward the radial inside.

In an embodiment, the inner race has an inner race track formed on an outer peripheral surface and includes a radially inner chamfered portion formed at a connection portion between an inner peripheral surface and both axial end surfaces.

In the inner race, the metal flow inside the inner race is continuous along the radially inner chamfered portion in the vicinity of the surface of the radially inner chamfered portion.

In an embodiment, a radial rolling bearing includes: an outer race which has an outer race track formed on an inner peripheral surface and includes a pair of radially outer chamfered portions formed at a connection portion between an outer peripheral surface and both axial end surfaces; an inner race which has an inner race track formed on an outer peripheral surface and includes a pair of radially inner chamfered portions formed at a connection portion between an inner peripheral surface and both axial end surfaces; and a plurality of rolling elements which are arranged between the outer race track and the inner race track in a rollable manner.

Particularly, in the radial rolling bearing of the present invention, the outer race is composed of the outer race of the present invention and the inner race is composed of the inner race of the present invention.

In an embodiment, a sliding bearing includes a pair of chamfered portions formed at a connection portion between an outer peripheral surface and both axial end surfaces or a connection portion between an inner peripheral surface and both axial end surfaces.

In the sliding bearing, the metal flow is continuous along each chamfered portion in the vicinity of the surface of each of the pair of chamfered portions.

In an embodiment, the rotating mechanical device includes a bearing.

In the rotating mechanical device, the bearing is composed of the radial rolling bearing or the sliding bearing.

In an embodiment, the vehicle includes a bearing.

Particularly, in the vehicle, the bearing is composed of the radial rolling bearing or the sliding bearing.

REFERENCE SIGNS LIST

1Radial rolling bearing2Outer race2aOuter race track2b1,2b2Radially outer chamfered portion3Inner race3aInner race track3b1,3b2Radially inner chamfered portion4Rolling element5Billet6First press working device6aPunch6bCounter punch6cFloating die6dElastic member7First intermediate material7aDisc-shaped portion7bSmall diameter cylindrical portion8Second press working device8aDie8a1Large diameter portion8a2Small diameter portion8a3Stepped surface8bPunch8cMandrel8dCavity9Second intermediate material9aSide plate portion9bLarge diameter cylindrical portion9cSmall diameter cylindrical portion9dBottom portion10Columnar material (billet)11Large diameter cylindrical member (first ring element)12Small diameter cylindrical member (second ring element)13Preliminary intermediate material (first piece)13aSide plate portion13bLarge diameter cylindrical portion (first ring portion)13cSmall diameter cylindrical portion (second ring portion)14Preliminary material (first piece)15Press working device15aDie15a1Large diameter portion15a2Small diameter portion15a3Stepped surface15bMandrel15cPunch16First intermediate material (second piece)16aLarge diameter cylindrical portion (third ring portion)16bSmall diameter cylindrical portion (fourth ring portion)16cConnection plate portion16dPartition wall portion17Press working device17aDie17a1Large diameter portion17a2Small diameter portion17a3Stepped surface17bInner pressing punch (second member)17b1Chamfer forming portion17cOuter pressing punch (first member)17dPresser punch17eInner counter punch (fourth member)17e1Chamfer forming portion17fOuter counter punch (third member)18Second intermediate material18aLarge diameter cylindrical portion18bSmall diameter cylindrical portion18cConnection plate portion18dPartition wall portion19Press working device19aDie19a1Large diameter portion19a2Small diameter portion19a3Stepped surface19a3aFlat surface portion19a3bChamfer forming portion19bPressing punch19cMandrel19dSleeve20Third intermediate material20aLarge diameter cylindrical portion20bSmall diameter cylindrical portion20cConnection plate portion21Press working device21aDie21bShaving cutter21b1Blade portion21cPresser punch22Preliminary large diameter cylindrical member22aLarge diameter cylindrical portion22bInward flange portion23Press working device23aDie23bSleeve23cPresser punch23c1Punching punch24Press working device24aDie24bSleeve24b1Chamfer forming portion24cShaving cutter24c1Blade portion25First intermediate material (first piece)25aLarge diameter cylindrical portion (first ring portion)25bSmall diameter cylindrical portion (second ring portion)25cConnection plate portion26Press working device26aDie26a1Large diameter portion26a2Small diameter portion26a3Stepped surface26a3aFlat surface portion26a3bChamfer forming portion26bPressing punch26cPunching punch27Second intermediate material (second piece)27aLarge diameter cylindrical portion (third ring portion)27bSmall diameter cylindrical portion (fourth ring portion)27cConnection plate portion28Press working device28aDie28a1Large diameter portion28a2Small diameter portion28a3Stepped surface28bInner pressing punch (second member)28b1Chamfer forming portion28cOuter pressing punch (first member)28dPresser punch28eInner counter punch (fourth member)28e1Chamfer forming portion28fOuter counter punch (third member)29Press working device29aDie29hSleeve29cShaving cutter29c1Blade portion30First intermediate material (first piece)30aLarge diameter cylindrical portion (first ring portion)30bSmall diameter cylindrical portion (second ring portion)30cConnection plate portion31Press working device31aDie31bPresser punch31b1Small diameter portion31b2Large diameter portion31b3Stepped surface31cPunching punch32Second intermediate material (first piece, second piece)32aLarge diameter cylindrical portion (first ring portion, third ring portion)32bSmall diameter cylindrical portion (second ring portion, fourth ring portion)32b1Extra thick portion32cConnection plate portion33Third intermediate material (second piece)33aLarge diameter cylindrical portion (third ring portion)33bSmall diameter cylindrical portion (fourth ring portion)33cConnection plate portion33dExtra thick portion34Press-working device34aDie34a1Large diameter portion34a2Small diameter portion34a3Chamfer forming portion34bMandrel (fourth member)34b1Small diameter portion34b2Large diameter portion34b3Stepped surface34cSleeve (third member)34dPressing punch (first member)34eIroning punch (second member)35Press working device35aDie35a1Small diameter portion35a2Large diameter portion35a3Stepped surface35bPresser punch35cPunching punch35dShaving cutter36Press working device36aDie36a1Large diameter portion36a2Small diameter portion36a3Stepped surface36a3aChamfer forming portion36bPresser punch36cPressing punch36dShaving cutter36eCounter punch37Second intermediate material37aLarge diameter cylindrical portion37bSmall diameter cylindrical portion37cConnection plate portion38First intermediate material (second piece)38aLarge diameter cylindrical portion (third ring portion)38bSmall diameter cylindrical portion (fourth ring portion)38cConnection plate portion39First intermediate material (first piece)39aSide plate portion39bLarge diameter cylindrical portion (first ring portion)39cSmall diameter cylindrical portion (second ring portion)40Second intermediate material (second piece)40aLarge diameter cylindrical portion (third ring portion)40bSmall diameter cylindrical portion (fourth ring portion)40cConnection plate portion40dPartition wall portion41Third preliminary intermediate material41aLarge diameter cylindrical portion41bSmall diameter cylindrical portion41cConnection plate portion42Second intermediate material42aLarge diameter cylindrical portion42bSmall diameter cylindrical portion42cConnection plate portion43Third intermediate material43aLarge diameter cylindrical portion43bSmall diameter cylindrical portion43cConnection plate portion44First preliminary large diameter cylindrical member44aLarge diameter cylindrical portion44bInward flange portion45Second preliminary large diameter cylindrical member45aLarge diameter cylindrical portion45bInward flange portion