Method for manufacturing a corrugated retainer, corrugated retainer, and rolling bearing

Abstract

This invention provides a corrugated bearing holder that can be applied to small-diameter rolling bearings and suppresses deformation and distortion. [Solution] A method for manufacturing a waveform holder 300, wherein each of the first waveform holder member 100 and the second waveform holder member 200 has a structure in which curved holding parts 101, 102, 201, 202 for holding rolling elements 401, 402 and connecting parts 103, 203 for connecting these holding parts are arranged adjacent to each other in the circumferential direction, and a through hole 104 is formed in the connecting part 103 of the first waveform holder member 100, and the second waveform holder A method for manufacturing a waveform holder 300, comprising the steps of: inserting the protrusion 204 into the through hole 104; and pressing the tip of the protrusion 204 to generate pressure that expands the protrusion 204 in a direction perpendicular to the axial direction, thereby pressing the side surface of the protrusion 204 against the inner surface of the through hole 104 to connect the first waveform holder 100 and the second waveform holder 200.

Description

Technical Field

[0001] The present invention relates to a technique for holding rolling elements in a rolling bearing.

Background Art

[0002] A rolling bearing includes an inner ring, an outer ring, rolling elements held between the inner ring and the outer ring, and a cage (retainer) for holding the rolling elements. There is a wave-shaped cage as the cage. The wave-shaped cage has a structure in which two wave-shaped cage members divided in the axial direction of the ball bearing are integrated while sandwiching the rolling elements. As the wave-shaped cage, those described in Patent Document 1 and Patent Document 2 are known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 and Patent Document 2 disclose a structure in which two wave-shaped cage members are joined with rolling elements sandwiched therebetween.

[0005] Patent Document 1 describes a configuration in which two corrugated retaining members are joined by inserting a through-hole formed in one corrugated retaining member into a through-hole formed in the other corrugated retaining member and expanding the diameter of the tip. This structure requires the formation of a through-tube projection and is not suitable for small-diameter rolling bearings. The through-tube projection needs to have a certain diameter. However, small-diameter rolling bearings have a small area at the joint. Therefore, when the structure of Patent Document 1 is applied to a small-diameter rolling bearing, securing the joint area becomes a problem. If the above-mentioned through-tube projection is formed at the small area of ​​the joint, the area occupied by the projection becomes relatively large, leading to problems of insufficient strength at the joint and distortion and deformation at the joint and its surroundings.

[0006] Patent Document 2 describes a structure in which two corrugated retaining members are joined by passing a projection formed on one corrugated retaining member through a through hole formed on one corrugated retaining member and crimping the tip of the projection to flatten it. In this structure, the length of the projection is necessary, so if the projection is created by plastic deformation, deformation and distortion of the corrugated retaining member around the projection will occur. Although a structure in which the projection is provided as a separate component can be considered, it would increase the number of parts and the assembly process, making it undesirable from a cost perspective.

[0007] Against this backdrop, the present invention aims to provide a corrugated retainer that can be applied to small-diameter rolling bearings and that suppresses deformation and distortion. [Means for solving the problem]

[0008] The present invention relates to a method for manufacturing a corrugated retainer having a structure in which a first member and a second member are joined together, wherein each of the first member and the second member has a structure in which a curved holding portion for holding rolling elements and a connecting portion for connecting the holding portions are arranged adjacent to each other in the circumferential direction, a through hole is formed in the connecting portion of the first member, and a convex portion and a concave portion are formed in the connecting portion of the second member, the axial length of which is shorter than the axial length of the through hole, and the method for manufacturing a corrugated retainer includes the steps of inserting the convex portion into the through hole, and pressing the tip of the convex portion to generate pressure that expands the convex portion in a direction perpendicular to the axial direction, pressing the side surface of the convex portion against the inner surface of the through hole to join the first member and the second member.

[0009] The present invention relates to a corrugated retainer comprising a curved retaining portion for holding rolling elements and a connecting portion for connecting the retaining portions, provided so as to be adjacent to each other in the circumferential direction, wherein the connecting portion of the first member is provided with a through hole, and the connecting portion of the second member is provided with a protrusion and a recess whose axial length is shorter than the axial length of the through hole, the protrusion being inserted into the through hole, and a pressure acting on the protrusion inserted into the through hole causing the side surface of the protrusion to press against the inner surface of the through hole, thereby connecting the first member and the second member. [Effects of the Invention]

[0010] According to the present invention, a corrugated retainer can be obtained that can be applied to small-diameter rolling bearings and in which deformation and distortion are suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] This is an external view of the waveform holder of the embodiment. [Figure 2] This is a diagram showing the manufacturing process of a waveform holder. [Figure 3] This diagram shows the process of forming the protrusion. [Figure 4] This diagram shows the process of joining the two components that make up the waveform holder. [Figure 5]This is a cross-sectional view of a rolling bearing. [Modes for carrying out the invention]

[0012] (1) Definition of terms In this specification, the axial direction is defined as the direction of the axis of rotation of the rolling bearing. The radial direction is defined as the direction perpendicular to the axial direction. The radially inward direction is defined as the direction approaching the axis of rotation of the rolling bearing in the radial direction. The radially outward direction is defined as the direction away from the axis of rotation of the rolling bearing in the radial direction. The circumferential direction is defined as the direction along the circle centered on the axis of rotation.

[0013] (2) Structure of the corrugator Figure 1 is an external view of the corrugated retainer of the embodiment, viewed from a direction perpendicular to the axis of rotation. Figure 2 is a diagram showing the manufacturing process of the corrugated retainer of the embodiment. Figure 2 is also a cross-sectional view of a part of Figure 1 cut along the circumferential direction, viewed from a direction perpendicular to the axis of rotation. Note that the rolling elements are omitted from the illustration in Figure 1.

[0014] Figures 1 and 2 show a corrugated retainer 300. The corrugated retainer 300 functions as a retainer for holding rolling elements. The corrugated retainer 300 has an annular structure. The corrugated retainer 300 has a structure in which a first corrugated retaining member 100, which is a first member, and a second corrugated retaining member 200, which is a second member, are connected in the axial direction. The rolling elements are held in a rotatable state between the first corrugated retaining member 100 and the second corrugated retaining member 200. In the case of Figure 1, the rolling elements are held in a rotatable state in the space indicated by reference numerals 301 and 302.

[0015] The first wave-holding member 100 and the second wave-holding member 200 have an annular structure formed by processing a plate-shaped member, and have a structure in which a plurality of holding parts for holding rolling elements and a plurality of connecting parts for connecting adjacent holding parts are repeatedly provided along the circumferential direction.

[0016] As shown in FIG. 2, the first waveform holding member 100 includes a curved holding portion 101 that holds the rolling element 401, a curved holding portion 102 that holds the rolling element 402, and a plate-like connecting portion 103 that connects the holding portions 101 and 102. As shown in FIG. 1, the holding portions 101 and 102 have a curved shape that can hold the spherical rolling elements so as to enclose them. This is the same for the holding portions of other first waveform holding members and the holding portions of the second waveform holding members.

[0017] Also, as shown in FIG. 2, the second waveform holding member 200 includes a curved holding portion 201 that holds the rolling element 401, a curved holding portion 202 that holds the rolling element 402, and a plate-like connecting portion 203 that connects the holding portions 201 and 202.

[0018] In the first waveform holding member 100, the structure of the holding portion 101 and the connecting portion 103 continuous thereto is repeatedly provided adjacent to each other in the circumferential direction. Also, in the second waveform holding member 200, the structure of the holding portion 201 and the connecting portion 20

[0019] The first waveform holding member 100 and the second waveform holding member 200 are made of a metal plate capable of plastic working with the same thickness. Examples of the metal plate capable of plastic working include cold-rolled steel sheets. The repeated dimensions of the holding portion and the connecting portion are the same in the first waveform holding member 100 and the second waveform holding member 200.

[0020] The rolling element 401 is held between the holding portion 101 and the holding portion 201. The rolling element 402 is held between the holding portion 102 and the holding portion 202. A through hole 104 penetrating in the axial direction is provided in the connecting portion 103 of the first waveform holding member 100. Through holes similar to the through hole 104 are also formed in other connecting portions of the first waveform holding member 100. In the present embodiment, the shape of the through hole 104 as viewed from the axial direction is circular.

[0021] The connecting portion 203 is provided with a protrusion 204, which is a means for connecting with the first wave-holding member 100. The protrusion 204 has a circular cross-section when viewed from the axial direction and protrudes axially toward the first wave-holding member 100. On the back side of the protrusion 204, there is a recess 205 formed during the process of forming the protrusion 204. Similar structures to the protrusion 204 and recess 205 are similarly formed in other connecting portions of the second wave-holding member 200.

[0022] The through holes (one of which is through hole 104) formed in each connecting portion of the first waveform holding member 100 and the protrusions (one of which is protrusion 204) formed in each connecting portion of the second waveform holding member 200 are set so that their positions align in the axial direction.

[0023] The protrusion 204 and the through hole 104 are set to be in a clearance fit relationship. Alternatively, the relationship between them could be set to an interference fit relationship.

[0024] (3) Protrusion formation process Figure 3 shows the process of forming the protrusion 204. First, the connecting portion 203, which is the workpiece, is placed on the die 501, which has a recess 502. Then, the side of the connecting portion 203 opposite to the side that contacts the die 501 is pressed down by the stopper 503, which has a through hole 504. At this time, the center position of the through hole 504 and the recess of the recess 502 are aligned. This state is shown in Figure 3(A). Note that the recess 502 of the die 501 is not limited to a recess, and may have a shape such as a hole.

[0025] Next, the punch 505 is inserted into the through hole 504 of the stopper 503, and the connecting portion 203 is plastically deformed by the punch 505 at the position of the through hole 504. At this time, the portion of the connecting portion 203 that is pressed by the punch 505 is plastically deformed so that it protrudes in the direction of the recess 502 of the die 501. This forms the convex portion 204. This state is shown in Figure 3(B).

[0026] After forming the protrusion 204, the die 501, punch 505, and stopper 503 are removed, and the front and back sides of the connecting portion 203 are reversed (turned inside out) to obtain the state shown in Figure 3(C). Figure 3(C) shows the recess 205 formed by being pressed by the punch 505, and the protrusion 204 that protrudes from the back side of the recess 205 as a result of the recess 205 being formed.

[0027] In the process of forming the protrusion 204, the amount of movement of the punch 505 is adjusted so that the protrusion length b of the protrusion 204 relative to the thickness c of the connecting portion 203 is b / c = 0.5 to 0.8, preferably b / c = 0.6 to 0.7. The depth dimension a of the recess 205 is approximately the same as the protrusion length b of the protrusion 204.

[0028] (4) Assembly process of the waveform holding section Figure 2 shows a method for manufacturing a corrugated retainer 300 having a structure in which a first corrugated retaining member 100, which is a first member, and a second corrugated retaining member 200, which is a second member, are joined together, wherein each of the first corrugated retaining member 100 and the second corrugated retaining member 200 has a structure in which curved retaining parts 101, 102, 201, 202 for holding rolling elements 401, 402 and connecting parts 103, 203 for connecting these retaining parts are arranged adjacent to each other in the circumferential direction, and a through hole 104 is formed in the connecting part 103 of the first corrugated retaining member 100. The connecting portion 203 of the second waveform holding member 200 has a protrusion 204 and a recess 205 formed thereon, the axial length of which is shorter than the axial length of the through hole 104. The invention provides a method for manufacturing a waveform holder 300, which includes the steps of inserting the protrusion 204 into the through hole 104, and pressing the tip of the protrusion 204 to generate pressure that expands the protrusion 204 in a direction perpendicular to the axial direction, thereby pressing the side surface of the protrusion 204 against the inner surface of the through hole 104 to connect the first waveform holding member 100 and the second waveform holding member 200.

[0029] The following describes the details of the manufacturing process for the corrugated retainer 300 that holds the rolling elements. First, a first corrugated retaining member 100 without through holes and a second corrugated retaining member 200 without protrusions are formed by press working. Next, through holes 104 are formed in the first corrugated retaining member 100. Also, protrusions 204 are formed in the second corrugated retaining member 200 by the process shown in Figure 3. The process of forming the through holes 104 and the process of forming the protrusions 204 and recesses 205 can be performed in either order. It is also possible to form the through holes 104 first and then obtain the shape of the first corrugated retaining member 100. Furthermore, it is also possible to form the protrusions 204 and recesses 205 first and then obtain the shape of the second corrugated retaining member 200.

[0030] Next, the rolling elements are held in each holding portion of one of the waveform holding members. This state is shown in Figure 2(A). Figure 2(A) shows the state in which the rolling element 401 is held in the holding portion 201 of the second waveform holding member 200, and the rolling element 402 is held in the holding portion 202.

[0031] Next, the first wave-holding member 100 is temporarily connected to the second wave-holding member 200, which holds the rolling elements. This state is shown in Figure 2(B). In this temporary connection, the protrusion 204 provided on the connecting portion 203 of the second wave-holding member 200 is inserted into the through hole 104 provided on the connecting portion 103 of the first wave-holding member 100. The process of this step is shown in Figures 4(A) and 4(B). The same procedure is performed at other connecting portions between the first wave-holding member 100 and the second wave-holding member 200.

[0032] Next, crimping is performed on the top of the protrusion 204. Details of this process are shown in Figures 4(C) and 4(D). First, a crimping die 511 having a protrusion is inserted into a recess 205 formed in the connecting portion 203 of the second corrugated retaining member 200. In this state, a crimping punch 512 with a pointed tip is pressed against the center of the top of the protrusion 204, causing the crimping punch 512 to be embedded in the top of the protrusion 204. This forms a recess on the top of the protrusion 204. This state is shown in Figure 4(D). The same process is performed at other connecting portions of the first corrugated retaining member 100 and the second corrugated retaining member 200.

[0033] When the caulking punch 512 sinks into the top (tip) of the convex portion 204, the convex portion 204 attempts to expand in diameter, and the side surface of the convex portion 204 is pressed against the inner peripheral surface of the through hole 104 with pressure. That is, when the caulking punch 512 is pushed into the top (tip) of the convex portion 204, the upper part of the convex portion 204 attempts to expand in a direction perpendicular to the axial direction of the convex portion 204, and the side surface of the convex portion 204 is pressed against the inner peripheral surface of the through hole 104 with pressure. As a result, the convex portion 204 is fixed inside the through hole 504. The same thing is also done at other connecting portions of the first waveform holding member 100 and the second waveform holding member 200.

[0034] When the convex portion 204 and the through hole 104 are in a clearance fit relationship, in the process of FIG. 4(D), the convex portion 204 expands in diameter by the set clearance.

[0035] Thus, the state shown in FIG. 2(C), that is, the state in which the first waveform holding member 100 and the second waveform holding member 200 are connected by caulking at the connecting portions 103 and 203 with the rolling elements 401 and 402 sandwiched therebetween, is obtained. Here, an example in which the top of the caulking punch 512 is pointed has been given, but it is not limited thereto, and the shape of the caulking punch may be a cylinder, a quadrangle, a hemispherical shape, or the like.

[0036] The thickness (axial dimension) of the connecting portion 103 and the connecting portion 203 is the same. Also, the dimensional relationship shown in FIG. 3(C) is b < c. Therefore, the axial length (projection length) of the convex portion 204 is shorter than the axial length (hole length) of the through hole 104. For this reason, in the state of FIG. 2(C), the tip of the convex portion 204 does not protrude from the through hole 104 and is located inside thereof.

[0037] (Regarding the numerical limitation of the convex portion) Figure 3(C) shows the dimensional relationship of the protrusion 204. The protruding length b of the protrusion 204 is adjusted so that b / c = 0.5 to 0.8, preferably b / c = 0.6 to 0.7, relative to the thickness c of the connecting portion 203. If b / c < 0.5, the contact area between the outer peripheral surface of the side of the protrusion 204 and the inner peripheral surface of the through hole 504 in the state shown in Figures 4(C) and (D) will be insufficient, resulting in insufficient bonding strength of the protrusion 204 to the through hole 504. Therefore, from the viewpoint of ensuring the bonding strength of the protrusion 204 to the through hole 504, it is preferable to set 0.5 ≤ b / c. If 0.6 ≤ b / c is set, the contact area between the outer peripheral surface of the side of the protrusion 204 and the inner peripheral surface of the through hole 504 will be larger, resulting in higher bonding strength. For the reasons above, the lower limit of b / c is set to 0.5 ≤ b / c, preferably 0.6 ≤ b / c.

[0038] On the other hand, if b / c > 0.8, the following problem arises. As shown in Figure 3(B), the convex portion 204 is formed by pressing the punch 505 into the connecting portion 203 and deforming the connecting portion 203 into a concave shape. In this process, the convex portion of the connecting portion 203 undergoes plastic deformation while dragging the surrounding members along with it. Alternatively, the portion of the connecting portion 203 surrounding the convex portion 204 is pulled toward the convex portion 204 as the convex portion 204 is formed. This tendency becomes greater the longer the protruding length of the convex portion 204.

[0039] When the above phenomenon becomes apparent, strain and deformation occur in the connecting portion 203 and the retaining portions 201 and 202 (see Figure 2) that are continuous with the connecting portion 203. This strain and deformation adversely affects the performance of the rolling bearing. This problem can be suppressed by setting the upper limit of b / c to around 0.8. For greater safety, it is safer to set the upper limit of b / c to around 0.7. For these reasons, the upper limit of b / c should be set to b / c ≤ 0.8, preferably b / c ≤ 0.7.

[0040] (5) Superiority The coupling structure of the first corrugation holding member 100 and the second corrugation holding member 200 shown in Figure 2 is simpler than coupling using claws or rivets, and also reduces the number of materials and parts.

[0041] In the case of small-diameter rolling bearings with a diameter of 30 mm or less, conventional technology has the problem of easily inducing deformation and distortion of the corrugated support portion. The protrusion 204 can be formed even in the small area of ​​the connecting portion of the small-diameter rolling bearing. Furthermore, by optimizing the protrusion length of the protrusion 204, it is possible to suppress the occurrence of the above-mentioned deformation and distortion while ensuring the joint strength.

[0042] (6) Examples of bearing devices Figure 5 is a cross-sectional view of a rolling bearing utilizing the present invention, cut across a section including the rotating shaft. Figure 5 shows a rolling bearing 600 utilizing the present invention. The rolling bearing 600 comprises an outer ring 601, an inner ring 602, and a plurality of rolling elements 603 held between the outer ring 601 and the inner ring 602. The plurality of rolling elements 603 are held in a corrugated retainer 300 shown in Figure 2. On the axially outer side of the corrugated retainer 300, a sealing member 604 is arranged to suppress leakage of grease filled between the outer ring 601 and the inner ring 602 and the intrusion of dust and other particles from the outside into the space between the outer ring 601 and the inner ring 602.

[0043] (7) Others Figure 2 shows an example of a straight hole with a constant inner diameter as the through hole 104. The through hole 104 may also have a shape in which the inner diameter gradually or in steps expands outward in the axial direction. In this case, the upper part of the protrusion 204 expands in diameter in the process shown in Figure 4(D). This structure can make the connection between the first corrugated member 100 and the second corrugated member 200 stronger.

[0044] It is also possible to make the shape of one or both of the through-hole 104 and the protrusion 204, when viewed from the axial direction, a shape other than circular. [Explanation of Symbols]

[0045] 100...First corrugation holding member, 101...Holding part, 102...Holding part, 103...Connecting part, 104...Through hole, 200...Second corrugation holding member, 201...Holding part, 202...Holding part, 203...Connecting part, 204...Convex part, 205...Concave part, 300...Corrugation holder, 301...Space where rolling elements are held, 302...Space where rolling elements are held, 401...Rolling element, 402...Rolling element, 501...Die, 502...Concave part, 503...Stopper, 504...Through hole, 505...Punch, 511...Crimping die, 512...Crimping punch, 600...Rolling bearing, 601...Outer ring, 602...Inner ring, 603...Rolling element, 604...Sealing member.

Claims

1. A method for manufacturing a corrugated retainer having a structure in which a first member and a second member are joined together, Each of the first member and the second member is, The structure has a curved holding portion that holds the rolling element and a connecting portion that connects the holding portion, which are arranged adjacent to each other in the circumferential direction. A through hole is formed in the connecting portion of the first member. The connecting portion of the second member is formed with a protrusion and a recess whose axial length is shorter than the axial length of the through hole. The steps include inserting the protrusion into the through hole, The process involves pressing the tip of the protrusion to generate pressure that expands the protrusion in a direction perpendicular to the axial direction, and pressing the side surface of the protrusion against the inner surface of the through hole to join the first member and the second member. A method for manufacturing a waveform holder, including the following:

2. The connecting portion of the second member is a plate-shaped member, The recess is formed by pressing the punch against the connecting portion. The method for manufacturing a corrugated retainer according to claim 1, wherein the recess is formed so that the protrusion is formed on the side opposite to the side to which the punch is pressed, in a portion corresponding to the portion to which the punch is pressed.

3. The method for manufacturing a waveform holder according to claim 2, wherein the value of the protruding length of the convex portion is 50% to 80% of the thickness of the connecting portion.

4. The device comprises a curved holding portion for holding the rolling element and a connecting portion for connecting the holding portion, and an annular first member and a second member provided adjacent to each other in the circumferential direction. A through hole is provided in the connecting portion of the first member. The connecting portion of the second member is provided with a protrusion and a recess whose axial length is shorter than the axial length of the through hole. The protrusion is inserted into the through hole, A pressure is applied to the protrusion inserted into the through hole, causing the side surface of the protrusion to press against the inner surface of the through hole. A corrugated retainer in which the first member and the second member are coupled by the aforementioned pressure.

5. The aforementioned connecting portion is a plate-shaped member, The waveform holder according to claim 4, wherein the protruding length of the convex portion is 50% to 80% of the thickness of the connecting portion.

6. A recess is formed at the top of the aforementioned protrusion. The waveform holder according to claim 5, wherein a pressure is applied around the recess to press the side surface of the protrusion against the inner surface of the through hole.

7. Rolling elements held in the waveform holder according to any one of claims 4 to 6, The outer ring and inner ring with the rolling elements sandwiched in between A rolling bearing having [a certain feature].

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