Rolling bearing

Abstract

This rolling bearing comprises: an outer ring including an outer rolling surface included in an inner peripheral surface; an inner ring including an inner rolling surface included in an outer peripheral surface and facing the outer rolling surface; a plurality of rolling elements capable of rolling with respect to the inner rolling surface and the outer rolling surface; and a separator disposed between the adjacent rolling elements. The separator is provided with: a lubrication part including a first surface facing in a first direction in a circumferential direction which is a direction along a pitch circle of the rolling elements, a second surface facing in a second direction opposite to the first direction in the circumferential direction, an inner peripheral surface extending from the first surface to the second surface, and an outer peripheral surface contiguous with an outer peripheral edge of each of the first surface and the second surface; a rotating body that is rotatably held with respect to the inner peripheral surface of the lubrication part and that includes a main part positioned in a through-hole, a first protruding part protruding from the first surface, and a second protruding part protruding from the second surface, the rotating body having a higher hardness than the hardness of the lubrication part; and a protective part disposed on the outer peripheral surface of the lubrication part and having a higher hardness than the hardness of the lubrication part.

Description

Rolling bearings

[0001] This application claims priority to Japanese Patent Application No. 2024-018553, filed February 9, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] A rolling bearing is known that includes an outer ring, an inner ring, a plurality of rolling elements, and a plurality of separators (see, for example, Patent Document 1). The separator described in Patent Document 1 is disposed between adjacent rolling elements. The separator contains only a solid lubricant. When the separator comes into contact with the adjacent rolling elements, the solid lubricant is supplied to the rolling elements.

[0003] JP 2013-32838 A

[0004] It is necessary to suppress wear of the separator caused by contact with the rolling elements.

[0005] The present disclosure provides a rolling bearing in which a lubricant is supplied to the rolling elements while wear of the separator is suppressed.

[0006] A rolling bearing according to the present disclosure comprises an outer ring including an outer rolling surface included in its inner circumferential surface, an inner ring arranged on the inner circumferential side of the outer ring, the inner ring being included in its outer circumferential surface and including an inner rolling surface facing the outer rolling surface, the inner ring having a central axis coinciding with the central axis of the outer ring, a plurality of rolling elements arranged between the outer ring and the inner ring, the plurality of rolling elements being capable of rolling on the inner rolling surface and the outer rolling surface, and a separator arranged between the outer ring and the inner ring and arranged between adjacent rolling elements.

[0007] the separator comprises: a lubricated portion including a first surface facing a first direction in the circumferential direction, which is a direction along the pitch circle of the rolling element; a second surface facing a second direction in the circumferential direction opposite to the first direction; an inner peripheral surface extending from the first surface to the second surface; and an outer peripheral surface continuing to the outer peripheral edges of the first surface and the second surface, the lubricated portion containing a lubricant; a rotating body rotatably held relative to the inner peripheral surface of the lubricated portion, the rotating body including a main portion located within a through hole defined by the inner peripheral surface of the lubricated portion and in contact with the inner peripheral surface of the lubricated portion, a first protrusion continuing from the main portion, the first protrusion protruding from the first surface, and a second protrusion continuing from the main portion and protruding from the second surface, the rotating body having a hardness higher than that of the lubricated portion; and a protective portion arranged on the outer peripheral surface of the lubricated portion, the protective portion having a hardness higher than that of the lubricated portion.

[0008] In the rolling bearing of the present disclosure, lubricant is supplied to the rolling elements, while wear of the lubricated parts is suppressed.

[0009] FIG. 1 is a perspective view of a rolling bearing according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the rolling bearing shown in FIG. 1 cut along a plane including the center axis. FIG. 3 is a side view of the rolling bearing shown in FIG. 1 viewed in the radial direction. FIG. 4 is a perspective view of the rolling elements and separator shown in FIG. 1. FIG. 5 is a perspective view of the separator shown in FIG. 4. FIG. 6 is a cross-sectional view of the separator shown in FIG. 5. FIG. 6 is a cross-sectional view perpendicular to a plane along the pitch circle. FIG. 7 is a cross-sectional view of the separator shown in FIG. 5. FIG. 7 is a cross-sectional view along a plane along the pitch circle. FIG. 8 is an enlarged cross-sectional view of the protrusion shown in FIG. 7. FIG. 9 is an enlarged cross-sectional view of the protrusion of a first modified example. FIG. 10 is an enlarged cross-sectional view of the protrusion of a second modified example. FIG. 11 is an enlarged cross-sectional view of the protrusion of a third modified example. FIG. 12 is an enlarged cross-sectional view of the protrusion of a fourth modified example.

[0010] [Summary of embodiment] A rolling bearing according to the present disclosure comprises: an outer ring including an outer rolling surface included in its inner circumferential surface; an inner ring arranged on the inner circumferential side of the outer ring, the inner ring being included in its outer circumferential surface and including an inner rolling surface facing the outer rolling surface, the inner ring having a central axis coinciding with the central axis of the outer ring; a plurality of rolling elements arranged between the outer ring and the inner ring, the plurality of rolling elements being capable of rolling on the inner rolling surface and the outer rolling surface; and a separator arranged between the outer ring and the inner ring and arranged between adjacent rolling elements.

[0011] the separator comprises: a lubricated portion including a first surface facing a first direction in the circumferential direction, which is a direction along the pitch circle of the rolling element; a second surface facing a second direction in the circumferential direction opposite to the first direction; an inner peripheral surface extending from the first surface to the second surface; and an outer peripheral surface continuing to the outer peripheral edges of the first surface and the second surface, the lubricated portion containing a lubricant; a rotating body rotatably held relative to the inner peripheral surface of the lubricated portion, the rotating body including a main portion located within a through hole defined by the inner peripheral surface of the lubricated portion and in contact with the inner peripheral surface of the lubricated portion, a first protrusion continuing from the main portion, the first protrusion protruding from the first surface, and a second protrusion continuing from the main portion and protruding from the second surface, the rotating body having a hardness higher than that of the lubricated portion; and a protective portion arranged on the outer peripheral surface of the lubricated portion, the protective portion having a hardness higher than that of the lubricated portion.

[0012] In this rolling bearing, lubricant is supplied to the rolling elements via the rotating body. The first protrusion of the rotating body can contact the rolling elements positioned in a first orientation relative to the first protrusion. The second protrusion of the rotating body can contact the rolling elements positioned in a second orientation relative to the second protrusion. This prevents contact between the lubricating portion and the rolling elements positioned in the first orientation relative to the first protrusion and the rolling elements positioned in the second orientation relative to the second protrusion. This prevents wear on the first and second surfaces of the lubricating portion.

[0013] The protective portion can contact the inner and outer raceway surfaces. This reduces wear on the outer circumferential surface of the lubricated portion. As a result, in this rolling bearing, lubricant is supplied to the rolling elements while reducing wear on the lubricated portion.

[0014] In the above-described rolling bearing, the rolling elements may be balls. This rolling bearing is suitable as a cross roller bearing. In this rolling bearing, even if the rotation axes of adjacent rolling elements are not parallel, the rolling elements can be prevented from providing excessive resistance to the rolling of the rolling elements.

[0015] In the above-described rolling bearing, the lubricated portion may further include a porous material that holds a lubricant and is capable of supplying the lubricant to the rotating body. In this rolling bearing, the lubricant is supplied from the porous material to the rolling body over a long period of time. Compared to the rolling bearing described in Patent Document 1, which contains only a solid lubricant, wear of the lubricated portion containing the porous material is further suppressed.

[0016] In the above-described rolling bearing, the material of the rotating body may be metal, which can effectively suppress wear of the lubricated portion.

[0017] In the above-described rolling bearing, the protective portion may be made of a resin or a metal. Resin and metal are suitable materials for forming the protective portion.

[0018] In the rolling bearing described above, the lubrication portion may have an annular shape, which simplifies the configuration of the lubrication portion.

[0019] In the above-described rolling bearing, one of the lubricating portion and the protective portion may include a protrusion, and the other may include a recess into which the protrusion fits. In this rolling bearing, the protrusion fits into the recess, thereby preventing the protective portion from falling off the lubricating portion.

[0020] In the above-mentioned rolling bearing, one of the projections and the recesses may be continuous over the entire outer peripheral surface in the circumferential direction. This rolling bearing configuration is simple, yet can effectively prevent the rolling bearing from falling off.

[0021] In the above-described rolling bearing, the protective portion may include a base and a protrusion that protrudes from the base toward the main portion of the rotating body. When the rolling bearing is used for a long period of time, the main portion may move toward the protective portion while pressing against the lubricating portion. However, in the rolling bearing of the present disclosure, the protrusion is supported by the base and can suppress movement of the main portion toward the base.

[0022] In the rolling bearing described above, the protrusion may include a third portion extending from the base portion toward the main portion, and a fourth portion connected to a tip end of the third portion and extending in a direction intersecting the direction of extension of the third portion. In this rolling bearing, the fourth portion can increase the rigidity of the protective portion.

[0023] In the above-described rolling bearing, the fourth part may include a first part extending from the tip end portion toward the first surface, and a second part extending from the tip end portion toward the second surface. In this rolling bearing, the first part and the second part can further increase the rigidity of the protective part.

[0024] In the above-described rolling bearing, the fourth part may extend at a right angle or an obtuse angle relative to the direction in which the third part extends. In this rolling bearing, the fourth part can further prevent the protective part from falling off the lubricated part, while allowing the lubricated part between the base part and the fourth part to contain a sufficient amount of lubricant.

[0025] In the above-described rolling bearing, the fourth portion may extend perpendicularly to the direction in which the third portion extends. In this rolling bearing, the fourth portion is easy to form and the configuration is simple.

[0026] In the above-described rolling bearing, the fourth portion may extend so that the distance from the main portion is equal to or less than the distance between the tip and the main portion. In this rolling bearing, the fourth portion can suppress, by the first portion and the second portion, movement of the main portion toward the first portion and movement of the main portion toward the second portion, respectively.

[0027] The rolling bearing described above may include a plurality of separators, so that the lubricant is efficiently supplied to the plurality of rolling elements.

[0028] [Specific Example of Embodiment] A specific example of the rolling bearing of the present disclosure will be described with reference to FIGS. 1 to 7 .

[0029] FIG. 1 is a perspective view of a rolling bearing according to an embodiment of the present disclosure. A portion of the outer ring is omitted from FIG. 1 . FIG. 2 is a cross-sectional view of the rolling bearing shown in FIG. 1 , cut along a plane including the center axis. FIG. 3 is a side view of the rolling bearing shown in FIG. 1 , viewed in the radial direction. FIG. 4 is a perspective view of rolling elements and a separator. FIG. 5 is a perspective view of the separator shown in FIG. 4 . FIGS. 6 and 7 are cross-sectional views of the separator shown in FIG. 5 . FIG. 6 is a cross-sectional view perpendicular to a plane along the pitch circle. FIG. 6 is a cross-sectional view taken along line XX in FIG. 7 . FIG. 7 is a cross-sectional view taken along a plane along the pitch circle. FIG. 7 is a cross-sectional view taken along line YY in FIG. 6 .

[0030] [Basic configuration of rolling bearing 1] As shown in Figure 1 , the rolling bearing 1 has, for example, a circular ring shape. The rolling bearing 1 has a central axis A. The central axis A is the axis of rotation of the rolling bearing 1. The rolling bearing 1 includes an outer ring 2, an inner ring 3, a plurality of rolling elements 4, and a plurality of separators 5.

[0031] [Outer ring 2] The outer ring 2 is a raceway ring located on the outer side of the rolling bearing 1. The outer ring 2 has an annular shape. The outer ring 2 has a central axis that coincides with the central axis A of the rolling bearing 1. The outer ring 2 is made of metal, and preferably steel.

[0032] [Inner ring 3] The inner ring 3 is a raceway ring located on the inner side of the rolling bearing 1. The inner ring 3 is arranged on the inner peripheral side of the outer ring 2. The inner ring 3 has an annular shape. The inner ring 3 has a central axis that coincides with the central axis A of the rolling bearing 1. The inner ring 3 is made of metal, and preferably steel.

[0033] [Rolling elements 4] A plurality of rolling elements 4 are arranged between the outer ring 2 and the inner ring 3. The plurality of rolling elements 4 are arranged at intervals from one another. The plurality of rolling elements 4 are lined up in the circumferential direction. The circumferential direction is along the direction of rotation of the rolling bearing 1. When the inner ring 3 rotates relative to the outer ring 2 around the central axis A, the plurality of rolling elements 4 roll while coming into contact with the outer ring 2 and the inner ring 3. This allows the inner ring 3 to rotate relative to the outer ring 2. In other words, the outer ring 2 and the inner ring 3 are rotatable relative to one another.

[0034] [Separators 5] A plurality of separators 5 are arranged between the outer ring 2 and the inner ring 3. Each of the plurality of separators 5 is arranged between adjacent rolling elements 4. For example, the plurality of separators 5 are arranged in the circumferential direction. The rolling elements 4 and the separators 5 are arranged alternately in the circumferential direction.

[0035] 2 , the outer ring 2 includes an outer peripheral surface 21 and an inner peripheral surface 22. The outer ring 2 includes a main body 23, a lid 24, and a pin 25.

[0036] The outer peripheral surface 21 forms the outer peripheral surface of the rolling bearing 1. The inner peripheral surface 22 is disposed at a distance from the outer peripheral surface 21 in the radial direction of the rolling bearing 1. The inner peripheral surface 22 faces the inner ring 3. The inner peripheral surface 22 includes an outer raceway surface 221, a relief groove 222, and a seal groove 223.

[0037] Outer raceway surface 221 is located in the middle of inner circumferential surface 22 in a cross section taken along a plane including central axis A. Outer raceway surface 221 includes first raceway surface 2211 and second raceway surface 2212. First raceway surface 2211 and second raceway surface 2212 are aligned in a direction along central axis A.

[0038] First raceway surface 2211 is located on one side of outer raceway surface 221 in a cross section cut along a plane including central axis A.

[0039] Second raceway surface 2212 is located on the other side of outer raceway surface 221 in a cross section taken along a plane including central axis A. Second raceway surface 2212 is disposed at a distance from first raceway surface 2211 in a cross section taken along a plane including central axis A. A plane along first raceway surface 2211 and a plane along second raceway surface 2212 are orthogonal in a cross section taken along a plane including central axis A. First raceway surface 2211 and second raceway surface 2212 are symmetrical with respect to plane P which is orthogonal to central axis A. Plane P is located between (at the center of) first raceway surface 2211 and second raceway surface 2212. First raceway surface 2211 and second raceway surface 2212 form outer grooved raceway 224. Outer grooved raceway 224 has a V-shape (or L-shape) that opens radially inward in a cross section taken along a plane including central axis A. The bending point of the V (or L) is located on the plane P.

[0040] The relief groove 222 is located in the center of the inner circumferential surface 22 in a cross section taken along a plane including the central axis A. The relief groove 222 is disposed between the first raceway surface 2211 and the second raceway surface 2212. The relief groove 222 is not included in the outer raceway groove 224.

[0041] The seal grooves 223 are located at both ends of the inner circumferential surface 22 in a cross section cut along a plane including the central axis A. Each of the two seal grooves 223 is connected to the first raceway surface 2211 and the second raceway surface 2212. A seal member (not shown) is fitted (press-fit) into the seal groove 223. The seal member seals the raceway B, which will be described later.

[0042] The main body 23 includes the outer peripheral surface 21 and the inner peripheral surface 22. The main body 23 includes a first through hole 211, a second through hole 212, and a third through hole 213.

[0043] As shown in FIGS. 2 and 3, the first through-hole 211 penetrates the main body 23 in the radial direction.

[0044] The second through hole 212 penetrates the main body 23 in the axial direction (a direction parallel to the central axis A). The second through hole 212 communicates with the first through hole 211.

[0045] 3, the third through hole 213 is disposed circumferentially at an interval from the first through hole 211. The third through hole 213 penetrates the main body 23 in the radial direction of the outer ring 2.

[0046] The outer surface of the lid 24 forms a part of the outer peripheral surface 21. In other words, the outer surface of the lid 24 and the outer surface of the main body 23 are included in the outer peripheral surface 21. The lid 24 closes the first through hole 211. As shown in FIG. 2 , the lid 24 includes a fourth through hole 241. The fourth through hole 241 penetrates the lid 24 in the axial direction (a direction parallel to the central axis A). When the lid 24 closes the first through hole 211, the fourth through hole 241 communicates with the second through hole 212.

[0047] The pin 25 is press-fitted into the second through-hole 212 and the fourth through-hole 241 with the lid 24 closing the first through-hole 211. This fixes the lid 24 to the main body 23.

[0048] [Details of Inner Ring 3] The inner ring 3 includes an outer peripheral surface 31 and an inner peripheral surface 32. The outer peripheral surface 31 includes an inner raceway surface 311 and a relief groove 312.

[0049] Inner raceway surface 311 faces outer raceway surface 221 in the radial direction relative to central axis A. Inner raceway surface 311 includes third raceway surface 3111 and fourth raceway surface 3112. Third raceway surface 3111 and fourth raceway surface 3112 are aligned in the direction along central axis A.

[0050] Third raceway surface 3111 is located on one side of inner raceway surface 311 in a cross section taken along a plane including central axis A. Third raceway surface 3111 is aligned with second raceway surface 2212. Specifically, third raceway surface 3111 is parallel to second raceway surface 2212.

[0051] Fourth raceway surface 3112 is located on the other side of inner raceway surface 311 in a cross section cut by a plane including central axis A. Fourth raceway surface 3112 is arranged at a distance from third raceway surface 3111 in a cross section cut by a plane including central axis A. A plane along third raceway surface 3111 and a plane along fourth raceway surface 3112 are orthogonal in a cross section cut by a plane including central axis A. Third raceway surface 3111 and fourth raceway surface 3112 are plane-symmetrical with respect to plane P described above. Fourth raceway surface 3112 is aligned with first raceway surface 2211. Specifically, fourth raceway surface 3112 is parallel to first raceway surface 2211.

[0052] The third raceway surface 3111 and the fourth raceway surface 3112 form an inner raceway groove 313. The inner raceway groove 313 faces the outer raceway groove 224 in the radial direction. The outer raceway groove 224 and the inner raceway groove 313 form a raceway B. The raceway B is a space (passage) between the outer ring 2 and the inner ring 3. The raceway B has an annular shape.

[0053] The relief groove 312 is located in the center of the outer peripheral surface 31 in a cross section cut along a plane including the central axis A. The relief groove 312 is disposed between the third raceway surface 3111 and the fourth raceway surface 3112. The relief groove 312 is not included in the inner grooved raceway 313.

[0054] [Details of Rolling Elements 4] A plurality of rolling elements 4 are arranged in the raceway B. Each of the plurality of rolling elements 4 is capable of rolling on the outer rolling surface 221 and the inner rolling surface 311. As shown in FIGS. 1 and 4 , the plurality of rolling elements 4 includes a plurality of first rolling elements 41 and a plurality of second rolling elements 42. The first rolling elements 41 and the second rolling elements 42 have the same shape. For example, each of the first rolling elements 41 and the second rolling elements 42 has a cylindrical shape. The first rolling elements 41 and the second rolling elements 42 have the same size. Each of the first rolling elements 41 and the second rolling elements 42 is made of metal, preferably steel. Specifically, the first rolling elements 41 and the second rolling elements 42 are rollers.

[0055] The first rolling elements 41 and the second rolling elements 42 are arranged alternately in the circumferential direction of the rolling bearing 1. When projected in a direction along the pitch circle PC, the central axes of adjacent first rolling elements 41 and second rolling elements 42 are perpendicular to each other. The pitch circle PC is a circle that passes through the centers of both end faces of the first rolling elements 41 and the second rolling elements 42 in the radial direction of the rolling bearing 1 when the multiple first rolling elements 41 and the multiple second rolling elements 42 are arranged in the raceway B. The trajectory of movement of the central axis of the first rolling elements 41 and the trajectory of movement of the central axis of the second rolling elements 42 are perpendicular to each other in a cross section cut along a plane including the central axis A. Specifically, the rolling bearing 1 is a cross roller bearing.

[0056] [Details of Separator 5] As shown in Figures 1 and 4, the separator 5 is disposed between the first rolling element 41 and the second rolling element 42. Specifically, the first rolling element 41, the separator 5, the second rolling element 42, and the separator 5 are arranged in this order in the circumferential direction. In the rolling bearing 1, units each consisting of the first rolling element 41, the separator 5, the second rolling element 42, and the separator 5 are repeatedly disposed in the circumferential direction. As shown in Figures 5 and 6, each of the multiple separators 5 has a disk (disk) shape. The separator 5 has a central axis C. The central axis C is aligned with the pitch circle PC. Each of the multiple separators 5 includes a lubricating portion 51, a rotating body 52, and a protective portion 53.

[0057] <Lubricating portion 51> The lubricating portion 51 has an annular shape. The lubricating portion 51 has a disk (disk) shape. For example, the lubricating portion 51 has a central axis that coincides with the central axis C of the separator 5. As shown in FIG. 7 , the lubricating portion 51 includes a first surface 511, a second surface 512, an inner circumferential surface 513, and an outer circumferential surface 514.

[0058] The first surface 511 faces a first direction D1. The first direction D1 is one direction in the circumferential direction PD, which is a direction along the pitch circle PC (see FIG. 4) of the rolling element 4. For example, the first surface 511 faces the first rolling element 41 (see FIG. 4). The first surface 511 is flat.

[0059] The second surface 512 faces a second direction D2. The second direction D2 is opposite to the first direction D1 in the circumferential direction PD. In other words, the second direction D2 is the other direction in the circumferential direction PD, which is the direction along the pitch circle PC of the rolling element 4. The second surface 512 is disposed at a distance from the first surface 511 in the circumferential direction PD. For example, the second surface 512 faces the second rolling element 42 (see FIG. 4 ). The second surface 512 is flat.

[0060] The inner circumferential surface 513 of the lubricated portion 51 extends from the first surface 511 to the second surface 512. The inner circumferential surface 513 defines a through hole 515. The through hole 515 penetrates the lubricated portion 51 in the circumferential direction PD. The through hole 515 opens between the first surface 511 and the second surface 512. The through hole 515 penetrates the lubricated portion 51 in the thickness direction. The inner circumferential surface 513 has an arc shape in a cross section along a plane along the pitch circle PC. The center of the arc is located within the through hole 515.

[0061] The outer peripheral surface 514 is continuous with the outer peripheral edges 5111, 5121 of the first surface 511 and the second surface 512. That is, the outer peripheral surface 514 extends from the outer peripheral edge 5111 of the first surface 511 (see FIG. 8 ) to the outer peripheral edge 5121 of the second surface 512 (see FIG. 8 ). As shown in FIG. 6 , the outer peripheral surface 514 extends along the circumferential direction PD2 of the separator 5.

[0062] As shown in FIG. 7 , the outer peripheral surface 514 includes a recess 5141. The recess 5141 is located in the middle of the outer peripheral surface 514 in the circumferential direction PD along the pitch circle PC of the rolling element 4. Specifically, the recess 5141 is located in the center of the outer peripheral surface 514 in the circumferential direction PD along the pitch circle PC of the rolling element 4. The recess 5141 is recessed from the periphery of the recess 5141 toward the central axis C. The periphery of the recess 5141 is on both sides of the recess 5141 in the circumferential direction PD along the pitch circle PC of the rolling element 4. As shown in FIG. 6 , the recess 5141 is continuous over the entire outer peripheral surface 514 in the circumferential direction PD2 of the separator 5. Only one recess 5141 is included in one outer peripheral surface 514. As shown in FIG. 7 , the recess 5141 has a rectangular shape in a cross section along the pitch circle PC.

[0063] The lubricating portion 51 includes a lubricant and a porous material. For example, the lubricant flows at 25° C. The lubricant includes, for example, lubricating oil.

[0064] The porous material holds the lubricant described above. Specifically, the porous material maintains (retains) the outer shape of the lubricated portion 51 while holding the lubricant inside its pores. For example, the porous material does not flow at 25°C. The porous material can supply the lubricant to the rotating body 52 described below. The material of the porous material is, for example, a fluororesin or a polyolefin resin. The material of the porous material is preferably a polyolefin resin.

[0065] The Shore hardness of the lubricated portion 51 at 25° C. is not less than Shore A 50 and not more than Shore A 70. The Shore hardness of the lubricated portion 51 is measured in accordance with the “Durometer hardness testing method for plastics” specified in JIS K7215.

[0066] <Rotating body 52> The rotating body 52 is located in the center of the separator 5. A portion of the rotating body 52 is disposed within the through-hole 515. The rotating body 52 is rotatably held relative to the inner circumferential surface 513 of the lubricating portion 51. The rotating body 52 includes a main portion 521, a first protruding portion 522, and a second protruding portion 523.

[0067] The main portion 521 is located within the through hole 515 of the lubricated portion 51. A portion of the circumferential surface of the main portion 521 faces the inner circumferential surface 513 of the lubricated portion 51. A portion of the circumferential surface of the main portion 521 contacts the inner circumferential surface 513 of the lubricated portion 51. A portion of the circumferential surface of the main portion 521 contacts the porous material in the lubricated portion 51.

[0068] The first protrusion 522 is capable of contacting a rolling element 4 (see FIG. 4 ) positioned in a first direction D1 relative to the first protrusion 522. The first protrusion 522 protrudes from the first surface 511 of the lubricated portion 51. The first protrusion 522 is continuous with the main portion 521. The first protrusion 522 is connected to a first end E1 of the main portion 521 in the circumferential direction PD. The first protrusion 522 is integral with the main portion 521. The protrusion length of the first protrusion 522 from the first surface 511 is equal to or greater than 0.1 mm and less than 1 mm. The protrusion length of the first protrusion 522 is the distance from the first end E1 to the tip of the first protrusion 522.

[0069] The second protrusion 523 is capable of contacting a rolling element 4 (see FIG. 4 ) positioned in a second direction D2 relative to the second protrusion 523. The second protrusion 523 protrudes from the second surface 512 of the lubrication portion 51. The second protrusion 523 is positioned on the opposite side of the main portion 521 from the first protrusion 522. The second protrusion 523 is continuous with the main portion 521. The second protrusion 523 is connected to a second end E2 of the main portion 521 in the circumferential direction PD. The second protrusion 523 is integral with the main portion 521. The protrusion length of the second protrusion 523 from the second surface 512 is the same as the protrusion length of the first protrusion 522. Specifically, the protrusion length of the second protrusion 523 from the second surface 512 is equal to or greater than 0.1 mm and less than 1 mm. The protrusion length of the second protrusion 523 is the distance from the second end E2 to the tip of the second protrusion 523.

[0070] The rotor 52 is a sphere. As shown in Fig. 6, the center of the sphere is located on the central axis C. As shown in Fig. 7, the center of the rotor 52 is located in the center of the separator 5.

[0071] The rotor 52 has a higher hardness than the lubricated portion 51. The rotor 52 has a Vickers hardness of HV772 or more and HV900 or less at 25° C. The Vickers hardness of the rotor 52 is measured in accordance with the “Vickers hardness test” specified in JIS Z 2244.

[0072] The rotor 52 is made of a metal, preferably steel, and is non-porous (or dense).

[0073] <Protective portion 53> As shown in Figures 6 and 7, the protective portion 53 is disposed on the outer peripheral surface 514 of the lubricating portion 51. The protective portion 53 covers the outer peripheral surface 514 of the lubricating portion 51. Specifically, the protective portion 53 covers the entire outer peripheral surface 514 of the lubricating portion 51. More specifically, the protective portion 53 is not disposed on the first surface 511 or the second surface 512, but is disposed only on the outer peripheral surface 514. The protective portion 53 has an annular shape. The protective portion 53 has a central axis that coincides with the central axis C of the separator 5. The protective portion 53 includes a fifth surface 531, a sixth surface 532, an outer peripheral surface 533, and an inner peripheral surface 534.

[0074] The fifth surface 531 faces the first direction D1. The fifth surface 531 is continuous with the first surface 511 of the lubricating portion 51. The fifth surface 531 is flat. The fifth surface 531 is flush with the first surface 511.

[0075] The sixth surface 532 faces the second direction D2. The sixth surface 532 is disposed at a distance from the fifth surface 531 in the circumferential direction PD. The sixth surface 532 is continuous with the second surface 512 of the lubricating portion 51. The sixth surface 532 is flat. The sixth surface 532 is flush with the second surface 512.

[0076] An outer peripheral surface 533 of the protective portion 53 forms the outer peripheral surface of the separator 5. The outer peripheral surface 533 connects the outer peripheral edges of the fifth surface 531 and the sixth surface 532. The outer peripheral surface 533 can come into contact with at least one of the outer raceway surface 221 and the inner raceway surface 311 (see FIG. 2 ). Preferably, the outer peripheral surface 533 can come into contact with both the outer raceway surface 221 and the inner raceway surface 311.

[0077] An inner circumferential surface 534 of the protective portion 53 is disposed at a distance from the outer circumferential surface 533 in the radial direction of the separator 5. The inner circumferential surface 534 connects the inner circumferential edge of the fifth surface 531 and the inner circumferential edge of the sixth surface 532. The inner circumferential surface 534 faces the outer circumferential surface 514 of the lubricating portion 51 in the radial direction of the separator 5. Specifically, the inner circumferential surface 534 contacts the outer circumferential surface 514 of the lubricating portion 51.

[0078] The inner circumferential surface 534 includes a protrusion 535. That is, the protective portion 53 includes the protrusion 535. The protrusion 535 is continuous over the entire inner circumferential surface 534 in the circumferential direction PD2 (the rotational direction of the rolling bearing 1) about the central axis A. Only one protrusion 535 is included on one inner circumferential surface 534. The protrusion 535 has a rectangular shape in a cross section along the pitch circle PC. The protrusion 535 fits into the recess 5141. One protrusion 535 fits into one recess 5141.

[0079] The protective portion 53 has a higher hardness than the lubricated portion 51. Specifically, the Rockwell hardness of the protective portion 53 at 25°C is HRR 123 or more and HRC 27 or less. For example, the protective portion 53 has a higher hardness than the lubricated portion 51 and a lower hardness than the rotating body 52. ​​HRR represents the Rockwell hardness measured in accordance with the "Determination of Plastic Hardness" specified in JIS K 7202-2. HRC represents the Rockwell hardness measured in accordance with the "Rockwell Hardness Test" specified in JIS Z 2245.

[0080] The material of the protective portion 53 is, for example, resin or metal. The material of the protective portion 53 is preferably resin from the viewpoint of obtaining excellent moldability. Examples of resin include engineering plastics, and preferred examples include polyphenylene sulfide resin (PPS) and polyether ether ketone resin (PEEK). The protective portion 53 may be porous or non-porous, and is preferably non-porous. A non-porous protective portion is a dense portion that does not contain any pores inside.

[0081] [Details of the protrusion 535] Fig. 8 is an enlarged cross-sectional view of the protrusion shown in Fig. 7. Details of the protrusion will be described with reference to Fig. 8. As shown in Fig. 8, the protective portion 53 includes a base portion 536 and the above-described protrusion 535.

[0082] The base 536 extends from the outer peripheral edge 5111 to the outer peripheral edge 5121 of the lubricating portion 51. The base 536 has a cylindrical shape with a central axis C that is common to the lubricating portion 51. The base 536 includes a second outer peripheral surface 5361, a second inner peripheral surface 5362, and two end surfaces 5363 and 5364. The second outer peripheral surface 5361 corresponds to the outer peripheral surface of the separator 5, which has a disk (disk) shape. The second inner peripheral surface 5362 is parallel to the central axis C in a cross section including the central axis C. The second inner peripheral surface 5362 extends from the outer peripheral edge 5111 of the first surface 511 toward the outer peripheral edge 5121 of the second surface 512 in a cross section including the central axis C. Specifically, the second inner peripheral surface 5362 has a linear shape parallel to the central axis C in a cross section including the central axis C. The second inner circumferential surface 5362 is disposed in contact with the main outer circumferential surface 5142 (the region of the outer circumferential surface 514 excluding the recessed portion 5141). The main outer circumferential surface 5142 is an outer circumferential surface included in the lubrication portion 51. The main outer circumferential surface 5142 is positioned in both the first direction D1 and the second direction D2 when viewed from the recessed portion 5141. The end surface 5363 corresponds to the fifth surface 531. The end surface 5364 corresponds to the sixth surface 532.

[0083] The protrusion 535 is connected to a central portion 5365 on the second inner circumferential surface 5362. The protrusion 535 extends from the central portion 5365 toward the main portion 521. Specifically, the protrusion 535 extends from the central portion 5365 toward the region (proximal region) 5211 closest to the central portion 5365 on the circumferential surface of the main portion 521.

[0084] A first ratio (L1 / L2), which is the ratio of the length L1 of the protrusion 535 to the length L2 of the base 536 in the circumferential direction PD, is 0.01 or greater, and may be 0.1 or greater. If the first ratio is equal to or greater than the above-mentioned lower limit, the volume of the lubricated portion 51 is not excessively reduced, and the lubricated portion 51 can supply a sufficient amount of lubricant to the rotating body 52. ​​The first ratio is equal to or less than 0.9, and may be less than 0.5, or may be equal to or less than 0.3. If the first ratio is equal to or less than the above-mentioned upper limit, the strength of the protrusion 535 can be increased. Note that the length L2 of the base 536 in the circumferential direction PD is the distance from the end face 5363 to the end face 5364. The length L1 of the protrusion 535 in the circumferential direction PD corresponds to the width of the protrusion 535.

[0085] The second ratio (L3 / L4), which is the ratio of the length L3 of the protrusion 535 to the length L4 of the lubricated portion 51 in the radial direction, is 0.01 or greater, and may be 0.1 or greater. If the second ratio is equal to or greater than the above-mentioned lower limit, the protective portion 53 can be further prevented from falling off the lubricated portion 51. The second ratio is less than 0.5, and may be equal to or less than 0.4, or may be equal to or less than 0.3. The protrusion 535 having the second ratio equal to or less than the above-mentioned upper limit is suitable for the protective portion 53. The length L3 of the protrusion 535 in the radial direction is the length of the protrusion 535 in the direction D3 in which the protrusion 535 extends (the protruding direction D3). The length L4 of the lubricated portion 51 in the radial direction is the distance from the second inner circumferential surface 5362 to the circumferential surface of the main portion 521 (the proximal region 5211).

[0086] [Method of Assembling Rolling Bearing 1] To assemble the rolling bearing 1, the outer ring 2, the inner ring 3, the plurality of rolling elements 4, and the plurality of separators 5 are prepared.

[0087] <Preparation of Separator 5> To prepare the separator 5, for example, first, the rotating body 52 and the protective portion 53 molded into the above-mentioned shape are prepared, and then the rotating body 52 is arranged inside the protective portion 53 with a gap therebetween. Then, a resin composition is arranged between the protective portion 53 and the rotating body 52. ​​The resin composition includes, for example, a lubricant, a porous material, and a porosifying agent. The porous material has a particle shape at 25°C. The average particle diameter of the porous material is, for example, 0.01 μm or more and 100 μm or less. A mold may be used to arrange the protective portion 53, the rotating body 52, and the resin composition. The mold has cavities corresponding to the rotating body 52, the lubricating portion 51, and the protective portion 53.

[0088] The resin composition is then heated (sintered), which removes the porosifying agent and forms a porous material, retaining the lubricant within the pores of the porous material. That is, a lubricated portion 51 is formed, which includes the lubricant and the porous material that retains the lubricant.

[0089] Thereafter, the rotor 52 is rotated relative to the lubricating portion 51 to release the rotor 52 from its adhesion to the lubricating portion 51, thereby making the rotor 52 rotatable relative to the lubricating portion 51. In this way, the separator 5 is prepared.

[0090] A plurality of rolling elements 4 and a plurality of separators 5 are disposed between the outer ring 2 and the inner ring 3 .

[0091] [Modification] The rolling bearing 1 may include only the first rolling element 41, without including the second rolling element 42. In this modification, the rotation axis of the first rolling element 41 (roller) and the rotation axis of the rolling bearing 1 are both parallel to the central axis A of the rolling bearing 11. In this modification, the rolling bearing 1 is a single-row roller bearing.

[0092] The rolling elements 4 may be balls. In this modification, the rolling bearing 1 is a ball bearing.

[0093] The lubrication portion 51 may have a rectangular frame shape.

[0094] The lubricating portion 51 may be made of only a lubricant that is solid (has no fluidity) at room temperature (25° C.) In other words, in this modification, the lubricating portion 51 does not include a porous material and includes only a lubricant.

[0095] The lubricating portion 51 may include a protrusion 535 and the protective portion 53 may include a recess 5141 .

[0096] The plurality of protrusions 535 may be arranged at intervals in the circumferential direction PD. The plurality of recesses 5141 may be arranged at intervals in the circumferential direction PD.

[0097] The plurality of protrusions 535 may be arranged at intervals in the rotation direction (circumferential direction) PD2 of the rolling bearing 1. The plurality of recesses 5141 may be arranged at intervals in the rotation direction (circumferential direction) PD2 of the rolling bearing 1.

[0098] The lubricating portion 51 may include a first protrusion and a first recess, and the protective portion 53 may include a second protrusion and a second recess. The first protrusion fits into the second recess. The second protrusion fits into the first recess.

[0099] The lubricating portion 51 may not include the protrusion or recess 5141. The protective portion 53 may not include the protrusion 535 or recess.

[0100] The protective portion 53 may be arranged on the outer peripheral edge of the first surface 511 or the outer peripheral edge of the second surface 512 in addition to the outer peripheral surface 514 of the lubricating portion 51 .

[0101] The rolling bearing 1 may include the separator 5 of the present disclosure and a separate second separator. In this modification, the separator 5 and the second separator are aligned in the circumferential direction about the central axis A. The second separator does not include a rotating body. The second separator has a disk shape. For example, the second separator includes only a lubricating portion and a protective portion. For example, the second separator includes only a lubricating portion and a rotating body.

[0102] [First Modification] Fig. 9 is an enlarged cross-sectional view of a protrusion of a first modification. Details of the protrusion 535 of the first modification will be described with reference to Fig. 9. As shown in Fig. 9, the protector 53 includes a base 536 and the protrusion 535.

[0103] In this modification, the second ratio (L3 / L4) is 0.5 or greater, and may be 0.6 or greater, 0.7 or greater, or 0.8 or greater. If the second ratio is equal to or greater than the above-described lower limit, movement of the rotating body 552 caused by the protrusion 535 can be more reliably suppressed. The second ratio is equal to or less than 0.95, and may be equal to or less than 0.9. If the second ratio is equal to or less than the above-described upper limit, lubricant can be reliably supplied to the main portion 521 from the lubrication portion 51 between the protrusion 535 and the main portion 521.

[0104] [Second Modification] Fig. 10 is an enlarged cross-sectional view of a protrusion of a second modification. Details of the protrusion 535 of the second modification will be described with reference to Fig. 10. As shown in Fig. 10, the protrusion 535 includes a third portion 5356 and a fourth portion 5357.

[0105] The third portion 5356 extends from the base portion 536 toward the main portion 521. In a cross section including the central axis C, the third portion 5356 has a linear shape extending from the base portion 536 to the proximal region 5211 of the main portion 521.

[0106] The fourth portion 5357 is connected to the tip 5351 of the third portion 5356. The fourth portion 5357 extends in a fourth direction D4 and a fifth direction D5. The fourth direction D4 and the fifth direction D5 each intersect with the third direction D3. The third direction D3 is the direction in which the third portion 5356 extends. In this second modified example, the fourth direction D4 and the fifth direction D5 each intersect with the third direction D3 in a cross section including the central axis C1. The fifth direction D5 is the opposite direction to the fourth direction D4. The fourth portion 5357 includes a first portion 5358 and a second portion 5359.

[0107] The first portion 5358 extends in the fourth direction D4. The first portion 5358 extends from the tip 5351 to approach the first surface 511. The first portion 5358 extends at a right angle to the third direction D3. In other words, the angle α1 formed by the line segment S1 connecting the tip 5351 of the third portion 5356 and the tip end of the first portion 5358 and the line segment S2 connecting the tip 5351 of the third portion 5356 and the central portion 5365 is a right angle.

[0108] The second portion 5359 extends in the fifth direction D5. The second portion 5359 extends from the tip 5351 toward the second surface 512. The second portion 5359 extends perpendicular to the third direction D3. In other words, the angle α2 formed by the line segment S2 and the line segment S3 connecting the tip 5351 of the third portion 5356 and the tip of the second portion 5359 is a right angle. The fourth portion 5357 has a linear shape in a cross section including the central axis C.

[0109] [Third Modification] Fig. 11 is an enlarged cross-sectional view of a protrusion of a third modification. Details of the protrusion 535 of the third modification will be described with reference to Fig. 11. As shown in Fig. 11, the fourth portion 5357 extends so as to form an obtuse angle with respect to the third direction D3.

[0110] The first portion 5358 extends at an obtuse angle with respect to the third direction D3. In other words, the angle α1 between the line segment S1 and the line segment S2 is an obtuse angle. In this modification, the angle α1 is greater than or equal to 100 degrees and less than or equal to 160 degrees. The distance L6 between the first portion 5358 and the main portion 521 is less than or equal to the distance L5 between the main portion 521 and the tip 5351. The first portion 5358 has a first opposing surface 5358S. The first opposing surface 5358S is parallel to a tangent to a portion of the circumferential surface of the main portion 521 that faces the first portion 5358.

[0111] The second portion 5359 extends at an obtuse angle with respect to the third direction D3. In other words, the angle α2 between the line segment S1 and the line segment S3 is an obtuse angle. In this modification, the angle α2 is greater than or equal to 100 degrees and less than or equal to 160 degrees. The distance L7 between the second portion 5359 and the main portion 521 is less than or equal to the distance L5. The second portion 5359 has a second opposing surface 5359S. The second opposing surface 5359S is parallel to a tangent to a portion of the circumferential surface of the main portion 521 that faces the second portion 5359. In this third modification, the distances L6 and L7 between the fourth portion 5357 and the main portion 521 are less than or equal to the distance L5 between the main portion 521 and the tip 5351.

[0112] [Fourth Modification] Figure 12 is an enlarged cross-sectional view of a protrusion of a fourth modification. Referring to Figure 12, the details of the protrusion 535 of the fourth modification will be described. As shown in Figure 12, the fourth portion 5357 extends from the tip 5351 along the circumferential surface of the main portion 521. The fourth portion 5357 curves along the circumferential surface of the main portion 521. The distances L6 and L7 are the same as the distance L5. The distances L6 and L7 are the same as each other. The first opposing surface 5358S and the second opposing surface 5359S are each a curved surface.

[0113] [Further Modifications of the Second to Fourth Modifications] The fourth section 5357 may include only the first portion 5358 and may not include the second portion 5359 .

[0114] The embodiments of the present disclosure are illustrative in all respects and should not be construed as limiting in any respect. The scope of the present invention is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0115] REFERENCE SIGNS LIST 1 Rolling bearing, 2 Outer ring, 3 Inner ring, 4 Rolling element, 5 Separator, 11 Rolling bearing, 21 Outer peripheral surface, 22 Inner peripheral surface, 23 Main body, 24 Cover, 25 Pin, 31 Outer peripheral surface, 32 Inner peripheral surface, 41 First rolling element, 42 Second rolling element, 51 Lubrication portion, 52 Rotating element, 53 Protective portion, 211 First through hole, 212 Second through hole, 213 Third through hole, 221 Outer rolling surface, 222 Relief groove, 223 Seal groove, 224 Outer raceway groove, 241 Fourth through hole, 311 Inner rolling surface, 312 Relief groove, 313 Inner raceway groove, 511 First surface, 512 Second surface, 513 Inner peripheral surface, 514 Outer peripheral surface, 515 Through hole, 521 Main portion, 522 1st protrusion, 523 2nd protrusion, 531 5th surface, 532 6th surface, 533 outer peripheral surface, 534 inner peripheral surface, 535 protrusion, 536 base, 552 rotating body, 2211 1st rolling surface, 2212 2nd rolling surface, 3111 3rd rolling surface, 3112 4th rolling surface, 5111 Outer peripheral edge, 5121 Outer peripheral edge, 5141 Recess, 5142 Main outer peripheral surface, 5211 Proximity region, 5351 Tip, 5356 Third part, 5357 Fourth part, 5358 First part, 5358S First opposing surface, 5359 Second part, 5359S First opposing surface, 5361 Second outer peripheral surface, 5362 Second inner circumferential surface, 5363 End surface, 5364 End surface, 5365 Center part, A Central axis, B orbit, C central axis, C1 central axis, D1 first direction, D2 second direction, D3 third direction, D4 fourth direction, D5 fifth direction, E1 first end, E2 second end, L5 distance, L6 distance, L7 distance, P surface, PC pitch circle, PD circumferential direction, PD2 circumferential direction, S1 line segment, S2 line segment, S3 line segment, α1 angle, α2 angle.

Claims

1. An outer ring including an outer rolling surface included in its inner circumferential surface; an inner ring arranged on the inner circumferential side of said outer ring, said inner ring including an inner rolling surface included in its outer circumferential surface facing said outer rolling surface, said inner ring having a central axis coinciding with a central axis of said outer ring; a plurality of rolling elements arranged between said outer ring and said inner ring, said plurality of rolling elements being capable of rolling on said inner rolling surface and said outer rolling surface; and a separator arranged between said outer ring and said inner ring and between adjacent rolling elements, said separator comprising: a first surface facing in a first direction in the circumferential direction, which is a direction along the pitch circle of said rolling elements, a second surface facing in a second direction in the circumferential direction opposite to said first direction, an inner circumferential surface extending from said first surface to said second surface, and an outer circumferential surface continuous with the outer peripheral edges of each of said first surface and said second surface, said lubrication portion containing a lubricant; a rotating body that is rotatably held relative to the inner peripheral surface of the lubricated portion, the rotating body including: a main portion located within a through hole defined by the inner peripheral surface of the lubricated portion and in contact with the inner peripheral surface of the lubricated portion; a first protrusion that is continuous with the main portion and protrudes from the first surface; and a second protrusion that is continuous with the main portion and protrudes from the second surface, the rotating body having a hardness higher than that of the lubricated portion; and a protective portion that is arranged on the outer peripheral surface of the lubricated portion and has a hardness higher than that of the lubricated portion.

2. The rolling bearing according to claim 1, wherein the rotating body is a ball.

3. A rolling bearing according to claim 1 or claim 2, wherein the lubrication portion further includes a porous material that holds the lubricant and is capable of supplying the lubricant to the rotating body.

4. A rolling bearing according to claim 1 or 2, wherein the material of the rotating body is metal.

5. A rolling bearing according to claim 1 or 2, wherein the protective portion is made of a resin or metal.

6. A rolling bearing according to claim 1 or 2, wherein the lubricating portion has an annular shape.

7. A rolling bearing as set forth in claim 1 or claim 2, wherein one of the lubricating portion and the protective portion includes a protrusion, and the other includes a recess into which the protrusion fits.

8. A rolling bearing according to claim 7, wherein the projections or recesses are continuous over the entire outer circumferential surface of the lubrication portion in the circumferential direction about the central axis.

9. A rolling bearing according to claim 1, wherein the protective portion includes: a base; and a protrusion that protrudes from the base toward the main portion of the rotating body.

10. A rolling bearing as set forth in claim 9, wherein the projection includes: a third portion extending from the base portion toward the main portion; and a fourth portion connected to the tip end of the third portion and extending in a direction intersecting the direction in which the third portion extends.

11. A rolling bearing as set forth in claim 10, wherein the fourth portion includes a first portion extending from the tip portion toward the first surface, and a second portion extending from the tip portion toward the second surface.

12. A rolling bearing according to claim 10, wherein the fourth portion extends at a right angle or an obtuse angle to the direction in which the third portion extends.

13. A rolling bearing according to claim 10, wherein the fourth portion extends perpendicular to the direction in which the third portion extends.

14. A rolling bearing according to claim 11, wherein the fourth portion extends so that the distance from the main portion is equal to or less than the distance between the tip and the main portion.

15. A rolling bearing according to claim 1 or 2, comprising a plurality of said separators.

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