Rolling bearing, rotary device and method for manufacturing rolling bearing

Abstract

To provide a rolling bearing capable of both ensuring durability and reducing rotational resistance.SOLUTION: A rolling bearing 1 comprises an inner ring 10 and an outer ring 20 arranged coaxially with each other, a rolling element 30 arranged between the inner ring 10 and the outer ring 20, a seal member 50 attached to the outer ring 20 and covering a space between the inner ring 10 and the outer ring 20 from the outside in an axial direction, and grease 60 placed between the rolling element 30 and the seal member 50. The outer ring 20 has an inner peripheral surface 22b facing the inner ring 10. The inner peripheral surface 22b is provided with an outer ring raceway surface 23 that supports the rolling element 30 so that it can roll, and a recess part 24 that is provided at a location extending axially from an axial end edge of the outer ring raceway surface 23 and is recessed in a radial direction. The grease 60 is in contact with the recess part 24. An unworked penetration of the grease 60 is larger than 178 and less than 287.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rolling bearing, a rotating device, and a method for manufacturing a rolling bearing. [Background technology]

[0002] Conventionally, there are rolling bearings that hold grease between a pair of raceways (inner and outer rings). In this type of rolling bearing, the resistance of the grease can be a factor that increases the rotational resistance. However, in rolling bearings, it is desirable to reduce the rotational resistance in order to reduce the power consumption of the rotating equipment in which they are mounted. In particular, there is a strong demand for reduced rotational resistance in small rolling bearings used in various motors such as fan motors.

[0003] In order to reduce the rotational resistance of a rolling bearing, it is effective to reduce the amount of grease that comes into contact with both of the components that rotate relative to each other. Therefore, by applying grease to the axial end of the fixed ring (in most cases, the outer ring) of the rolling bearing or to the seal member arranged on this end side, the amount of grease that comes into contact with the rolling elements (balls) and the cage that holds the rolling elements is reduced (see, for example, Patent Document 1). In the rolling bearing described in Patent Document 1, the grease adheres to the inner peripheral surface of the outer ring, avoiding the raceway surface that comes into contact with the rolling elements, and is enclosed in an annular shape biased toward the inner peripheral surface side of the outer ring so as not to come into contact with the outer peripheral surface of the inner ring.

[0004] Furthermore, there is a rolling bearing in which a recess is provided on the peripheral surface of the raceway ring, and grease is placed in the recess so that the grease does not easily come into contact with the rolling elements (see, for example, Patent Document 2). Patent Document 2 discloses a rolling bearing in which an outer ring has recesses formed on both axial sides of a raceway surface and a ridge formed between the recesses and the raceway surface, and the recesses have a mounting surface on which the grease is placed, and an inclined portion formed between the mounting surface and the ridge and approaching the outer peripheral surface of the outer ring toward the outside in the axial direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-150615 A [Patent Document 2] Patent No. 7209902 Summary of the Invention [Problem to be solved by the invention]

[0006] However, if the amount of grease is reduced to reduce the rotational resistance, the life of the rolling bearing may be shortened due to grease shortage. In addition, as in the configuration disclosed in Patent Document 2, if the grease is placed on the mounting surface on the opposite side of the ridge of the recess across the inclined portion, the base oil that seeps out of the grease must travel along the inclined portion and then overcome the ridge before reaching the raceway surface, which may result in insufficient supply of the base oil of the grease to the rolling elements. In particular, as the base oil seeps out of the grease, the ratio of the thickener in the grease increases, so that the supply capacity of the base oil may gradually decrease if the rolling bearing is operated for a long time. Therefore, in conventional rolling bearings, there is a problem of ensuring durability and reducing rotational resistance at the same time.

[0007] Therefore, the present invention provides a rolling bearing, a rotating device, and a method for manufacturing a rolling bearing, which can ensure durability while reducing rotational resistance. [Means for solving the problem]

[0008] A rolling bearing according to a first aspect of the present invention comprises an inner ring and an outer ring arranged coaxially with each other, rolling elements arranged between the inner ring and the outer ring, a sealing member attached to the inner ring or the outer ring and covering the space between the inner ring and the outer ring from the outside in the axial direction, and grease arranged between the rolling elements and the sealing member, wherein one of the inner ring and the outer ring has a circumferential surface facing the other of the inner ring and the outer ring, and the circumferential surface is formed with a raceway surface that rollably supports the rolling elements, and a radially recessed portion provided at a location extending in the axial direction from the axial end edge of the raceway surface, the grease is in contact with the recessed portion, and the unmixed penetration of the grease is greater than 178 and less than 287.

[0009] According to the first aspect, the recess can restrict the grease from being displaced in the axial direction. This can prevent the grease from being displaced and coming into contact with the rolling elements or the like in an amount greater than the desired amount. This can reduce the rotational resistance of the rolling bearing. Furthermore, since the grease can be disposed inside the recess, the total amount of grease can be increased compared to a configuration in which no recess is formed. Furthermore, the portion of the grease that is not in contact with the rolling elements and the cage is relatively soft and is easily separated from the outside. Therefore, even if the base oil in the portion of the grease that is in contact with the rolling elements or the cage becomes insufficient, the base oil seeps out from the inside of the grease that is not in contact with the rolling elements and the cage, and the base oil can be continuously supplied to the sliding part. Even if the grease is applied so as not to come into contact with the rolling elements and the cage, the base oil can be supplied to the sliding part from the surface of the grease, and the base oil can be supplied to the sliding part from the inside of the grease to the surface of the grease. Therefore, even if the grease is placed at a position away from the rolling elements and the cage in order to reduce the rotational resistance of the rolling bearing, the base oil can be supplied to the sliding part for a long period of time, and the durability of the rolling bearing can be improved. In addition, by having an unmixed penetration of less than 287, excessive deformation due to sagging or dragging caused by gravity of the grease can be suppressed, and the shape of the parts of the grease that are not in contact with the rolling elements and cage can be maintained in their original shape. This makes it possible to suppress variations in rotational resistance caused by differences in the shape of the grease for each rolling bearing. As a result, it is possible to provide a rolling bearing that can ensure durability and reduce rotational resistance at the same time.

[0010] A rolling bearing according to a second aspect of the present invention is the rolling bearing according to the first aspect, wherein the grease may be in contact with a portion of the recess that faces in a direction inclined outward in the axial direction with respect to the radial direction.

[0011] According to the second aspect, the recessed portion that faces a direction inclined axially outward with respect to the radial direction restricts the grease from displacing axially inward from the initial state. This makes it difficult for the grease to displace axially inward from its initial position as the rolling bearing is used repeatedly, so that the amount of grease to be enclosed can be increased and the above-mentioned effects can be obtained more reliably.

[0012] A rolling bearing according to a third aspect of the present invention is the rolling bearing according to the first or second aspect above, wherein the recess may have a portion that faces in a direction that is inclined inward in the axial direction with respect to the radial direction.

[0013] According to the third aspect, the recessed portion that faces in a direction inclined axially inward with respect to the radial direction restricts the grease from displacing axially outward, thereby preventing the grease or its base oil from flowing out toward the seal member and leaking from the gap between the seal member and one of the raceways.

[0014] A rolling bearing according to a fourth aspect of the present invention is the rolling bearing according to any one of the first to third aspects, wherein the grease may be in contact with the seal member.

[0015] According to the fourth aspect, when the seal member is attached with grease applied to one of the raceways, even if the grease in contact with the seal member is pushed inward in the axial direction by the seal member, the recess prevents the grease from displacing inward in the axial direction, so that it is possible to prevent more than a desired amount of grease from contacting the rolling elements, etc., and therefore it is possible to reduce the rotational resistance of the rolling bearing.

[0016] A rolling bearing according to a fifth aspect of the present invention is a rolling bearing according to any one of the first to fourth aspects described above, wherein the grease may be in contact with a ridge portion formed on an edge of the recess facing the raceway surface.

[0017] According to the fifth aspect, the base oil seeping out of the grease does not need to climb over ridges on the way to the raceway surfaces, so that it is possible to prevent the supply of the base oil of the grease to the rolling elements from being insufficient.

[0018] A rolling bearing according to a sixth aspect of the present invention is a rolling bearing according to any one of the first to fifth aspects above, wherein the one raceway has a protruding portion protruding toward the other raceway and having the circumferential surface formed thereon, the protruding portion having an end face facing outward in the axial direction and connecting to the circumferential surface at the periphery on the other raceway side, the circumferential surface having a connection surface formed between the recess and the end face, and the connection surface may be farther from the other raceway in the radial direction than the axial end edge of the raceway surface.

[0019] According to the sixth aspect, when the tip of the nozzle is inserted from the outside of the rolling bearing into the inside of the outer ring and the inner ring in order to discharge grease from the nozzle and apply it to a predetermined location, it is possible to make it difficult for the connection surface to come into contact with the nozzle. Therefore, it is easier to bring the nozzle close to the recess when applying grease, so that the productivity of small-diameter rolling bearings can be improved. In addition, since it is easier to bring the nozzle close to the recess, grease can be applied with high precision, and it is possible to prevent the grease from coming into contact with the rolling elements, etc., in an amount greater than the desired amount. Therefore, it is possible to reduce the rotational resistance of the rolling bearing.

[0020] A rolling bearing according to a seventh aspect of the present invention is a rolling bearing according to any one of the first to sixth aspects described above, wherein the circumferential surface may have an inclined portion extending from an edge of the recess on the raceway surface side toward the raceway surface at an incline with respect to the radial and axial directions.

[0021] According to the seventh aspect, even if the end of the recess on the raceway side extends along the radial direction, the circumferential surface gradually slopes from the recess toward the raceway surface, so that the base oil exuded from the grease can be encouraged to flow from the recess toward the raceway surface along the slope. Therefore, even if the grease is not disposed close to the raceway surface, it is possible to prevent the supply of the base oil of the grease to the rolling elements from being insufficient.

[0022] A rolling bearing according to an eighth aspect of the present invention is the rolling bearing according to the seventh aspect, wherein the grease is arranged so as not to protrude in the radial direction from the inside of the recess toward the inclined portion.

[0023] According to the eighth aspect, it is possible to prevent the grease from coming into contact with the rolling elements, and at the same time, since the amount of grease applied is reduced, it is possible to preferably obtain the effect of preventing the supply of the grease base oil to the rolling elements from becoming insufficient as described above.

[0024] A rolling bearing according to a ninth aspect of the present invention is the rolling bearing according to any one of the first to eighth aspects above, wherein the difference between worked penetration and unworked penetration of the grease is less than 50.

[0025] According to the ninth aspect, the softness of the grease in the portion not in contact with the rolling elements and the cage is close to the softness of the portion in contact with the rolling elements and the cage. This reduces the difference in the degree of base oil seepage between the portion of the grease in contact with the rolling elements or the cage and the portion not in contact with the rolling elements or the cage. This makes it possible to stabilize the rotational resistance of the rolling bearing for a long period of time.

[0026] A rolling bearing according to a tenth aspect of the present invention may be a rolling bearing according to any one of the first to ninth aspects above, wherein the ratio of the difference between the worked penetration and the unworked penetration to the worked penetration of the grease is less than 22.7%.

[0027] According to the tenth aspect, the softness of the grease portion not in contact with the rolling elements and the cage is close to the softness of the grease portion in contact with the rolling elements or the cage. This reduces the difference in the degree of base oil seepage between the portion of the grease in contact with the rolling elements or the cage and the portion not in contact with the rolling elements or the cage. This makes it possible to stabilize the rotational resistance of the rolling bearing for a long period of time.

[0028] A rolling bearing according to an eleventh aspect of the present invention is the rolling bearing according to any one of the first to tenth aspects above, wherein the unmixed penetration of the grease after being left at 85°C for 18 hours may be greater than 158.

[0029] According to the eleventh aspect, the degree of hardening of the grease can be set to such an extent that the base oil can smoothly seep out even if the grease is exposed to high temperatures or left for a long period of time, and therefore a rolling bearing with high durability can be formed.

[0030] A rotating device according to a twelfth aspect of the present invention comprises a rotatably arranged rotating body, a support body that rotatably supports the rotating body, and a rolling bearing according to any one of the first to eleventh aspects interposed between the rotating body and the support body.

[0031] According to the twelfth aspect, the rotating equipment is provided with a rolling bearing that ensures durability while reducing rotational resistance, thereby achieving a longer life for the rotating equipment and reduced power consumption by reducing the rotational resistance of the rotating body relative to the support.

[0032] A thirteenth aspect of the present invention relates to a method for manufacturing a rolling bearing comprising an inner ring and an outer ring arranged coaxially with each other, rolling elements arranged between the inner ring and the outer ring, a sealing member attached to the inner ring or the outer ring and covering the space between the inner ring and the outer ring from the outside in the axial direction, and grease arranged between the rolling elements and the sealing member, wherein one of the inner ring and the outer ring has a peripheral surface facing the other of the inner ring and the outer ring, and the peripheral surface is formed with a raceway surface that rollably supports the rolling elements, and a radially recessed portion provided at a location extending in the axial direction from an axial end edge of the raceway surface, the method comprising the step of applying the grease in contact with the recessed portion, and the unmixed penetration of the grease is greater than 178 and less than 287.

[0033] According to the thirteenth aspect, the grease can be applied to one of the races so that the axial displacement is restricted by the recess. This makes it possible to suppress the grease from displacing and contacting the rolling elements and the like in an amount greater than the desired amount. This makes it possible to reduce the rotational resistance of the rolling bearing. Furthermore, since the grease can be disposed inside the recess, the total amount of grease can be increased compared to the case where the grease is not applied to the recess. Furthermore, since the immiscible penetration of the grease is relatively small, the grease can be easily deformed in the radial direction when it is pushed axially inward by the sealing member. This makes it possible to suppress the grease from moving axially inward and to suppress the grease from contacting the rolling elements or the cage more than necessary. As a result, it is possible to manufacture a rolling bearing that can ensure durability and reduce rotational resistance at the same time.

[0034] A method of manufacturing a rolling bearing according to a fourteenth aspect of the present invention is the method of manufacturing a rolling bearing according to the thirteenth aspect above, wherein the seal member has an annular seat portion contacting the one raceway from the outside in the axial direction, an extension portion extending outward in the axial direction from a peripheral edge of the seat portion facing the other raceway of the inner ring and the outer ring, and a flat portion extending radially from an outer edge in the axial direction of the extension portion towards the other raceway, the flat portion being brought into contact with an outer edge of the grease in the axial direction; and after the contacting step, the sealing member is brought into contact with the one of the raceways so that the base portion comes into contact with the one of the raceways from the outside in the axial direction, and the flat portion is used to press the grease inward in the axial direction.

[0035] According to the fourteenth aspect, since the flat surface of the seal member contacts the axially outer edge of the grease in the contact step, the grease can be provided with room to spread radially toward the extension and seat of the seal member in the process of pushing the flat surface toward the axially inner side in the installation step. This makes it possible to prevent the grease from spreading too much toward the other raceway and the rolling body. This makes it easy to prevent the grease from directly contacting the rolling body and the other raceway. Moreover, because an extension is provided between the flat portion and the base, the grease is less likely to be pushed toward the rolling elements compared to a configuration in which the flat portion extends from the base toward the other raceway ring. This makes it possible to place the grease closer to the rolling elements in advance, thereby increasing the amount of grease. Effect of the Invention

[0036] According to the present invention, it is possible to provide a rolling bearing, a rotating device, and a method for manufacturing a rolling bearing, which can ensure durability and reduce rotational resistance at the same time. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a plan view of a rolling bearing according to a first embodiment. [Diagram 2] FIG. 2 is a vertical cross-sectional view taken along line II-II in FIG. [Diagram 3] 1 is a vertical sectional view of a rolling bearing illustrating a grease application method according to a first embodiment. FIG. [Figure 4] 1 is a vertical sectional view of a rolling bearing illustrating a grease application method according to a first embodiment. FIG. [Diagram 5] FIG. 4 is a vertical sectional view of a rolling bearing according to a first modified example of the first embodiment. [Figure 6] FIG. 4 is a vertical sectional view of a rolling bearing according to a second modified example of the first embodiment. [Figure 7] FIG. 11 is a vertical sectional view of a rolling bearing according to a third modified example of the first embodiment. [Figure 8] FIG. 11 is a vertical sectional view of a rolling bearing according to a fourth modified example of the first embodiment. [Figure 9] FIG. 6 is a vertical sectional view of a rolling bearing according to a second embodiment. [Figure 10] FIG. 11 is a vertical sectional view of a rolling bearing according to a third embodiment. [Figure 11] FIG. 11 is a vertical sectional view of a rolling bearing according to a fifth embodiment. [Figure 12] FIG. 13 is a vertical sectional view of a rolling bearing according to a modified example of the fifth embodiment. [Figure 13] FIG. 13 is a vertical sectional view of a rolling bearing according to a sixth embodiment. [Figure 14] FIG. 23 is a vertical sectional view of a rolling bearing according to a first modified example of the sixth embodiment. [Figure 15] FIG. 23 is a vertical sectional view of a rolling bearing according to a second modified example of the sixth embodiment. [Figure 16] FIG. 13 is a vertical sectional view of a rolling bearing according to a seventh embodiment. [Figure 17] FIG. 23 is a vertical sectional view of a rolling bearing according to a first modified example of the seventh embodiment. [Figure 18] FIG. 23 is a vertical sectional view of a rolling bearing according to a second modified example of the seventh embodiment. [Figure 19] FIG. 13 is a vertical sectional view of a rolling bearing according to an eighth embodiment. [Figure 20] FIG. 13 is a vertical sectional view of a rolling bearing according to a ninth embodiment. [Figure 21] FIG. 23 is a vertical sectional view of a rolling bearing according to a first modified example of the ninth embodiment. [Figure 22] FIG. 23 is a vertical sectional view of a rolling bearing according to a second modified example of the ninth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. In addition, duplicate descriptions of those components may be omitted.

[0039] [First embodiment] A first embodiment of the present invention will be described with reference to FIGS. Fig. 1 is a plan view of the rolling bearing according to the first embodiment. Fig. 2 is a vertical cross-sectional view taken along line II-II in Fig. 1. In Fig. 2, a rotating device 2 on which the rolling bearing 1 is mounted is shown by a virtual line.

[0040] 1 and 2, the rolling bearing 1 is a radial ball bearing including an inner ring 10 and an outer ring 20 which are raceways, a plurality of rolling elements 30, a cage 40, and a pair of seal members 50. The rolling bearing 1 is provided in a rotating device 2 such as a fan motor. The rotating device 2 includes a shaft 3 (rotating element) formed to be rotatable about a common axis O, and a housing 4 (support) which is fixedly installed and rotatably supports the shaft 3. The rolling bearing 1 is interposed between the shaft 3 and the housing 4.

[0041] The inner ring 10 and the outer ring 20 are arranged coaxially with each other such that their respective central axes coincide with the common axis O. In this embodiment, the direction in which the common axis O extends is referred to as the axial direction, the direction extending radially from the common axis O perpendicular to the common axis O is referred to as the radial direction, and the direction rotating around the common axis O is referred to as the circumferential direction. In addition, of the directions parallel to the axial direction and pointing in opposite directions, one is defined as the upward direction, and the other is defined as the downward direction.

[0042] The inner ring 10 is provided as a rotating ring. The inner ring 10 is fitted onto the shaft 3 and fixed to the shaft 3. The outer ring 20 is provided as a fixed ring. The outer ring 20 is fitted into a recess (or a through hole) of the housing 4 and fixed to the housing 4. The outer ring 20 surrounds the inner ring 10 from the outside in the radial direction with an annular space provided between the inner ring 10 and the outer ring 20. The multiple rolling elements 30 are disposed between the inner ring 10 and the outer ring 20 and are held by the retainer 40 so as to be rollable. The retainer 40 rotatably holds each of the rolling elements 30 with the multiple rolling elements 30 evenly arranged in the circumferential direction. The seal member 50 is attached to the outer ring 20 and covers the annular space between the inner ring 10 and the outer ring 20 from the outside in the axial direction.

[0043] The outer ring 20 is formed in an annular shape from a metal material such as stainless steel or bearing steel. However, the outer ring 20 is not limited to being made of metal, and may be formed from other materials. The outer ring 20 has an outer ring body 21 whose width in the axial direction is equal to the width of the inner ring 10 in the axial direction, and a protruding portion 22 that protrudes radially inward from the outer ring body 21 and extends over the entire circumferential direction. The protruding portion 22 is formed in a portion of the outer ring body 21 that is located at the center in the axial direction. The width of the protruding portion 22 in the axial direction is shorter than the width of the outer ring body 21 in the axial direction and is larger than the outer diameter of the rolling element 30.

[0044] The protruding portion 22 has a pair of end faces 22a facing outward in the axial direction, and an inner peripheral surface 22b (peripheral surface) connecting the inner peripheral edges of the pair of end faces 22a. Each end face 22a extends parallel to both the radial and circumferential directions. An outer ring raceway surface 23 is formed on the inner peripheral surface 22b, which is recessed toward the radially outward direction. The outer ring raceway surface 23 is formed in a hemispherical shape in cross section so as to follow the outer surface of the rolling element 30, and is formed in an annular shape extending in the circumferential direction around the entire circumference of the inner peripheral surface 22b. The outer ring raceway surface 23 is formed on a portion of the inner peripheral surface 22b that is located at the center in the axial direction.

[0045] Furthermore, the inner peripheral surface 22b is formed with a recess 24 recessed radially outward. The recess 24 is provided at a location on the inner peripheral surface 22b that extends axially from the axial end edge of the outer ring raceway surface 23. The recess 24 is provided above the outer ring raceway surface 23. The recess 24 is provided at an axial distance from the outer ring raceway surface 23. The recess 24 is provided at an axial distance from the upwardly facing end face 22a. The recess 24 extends continuously over the entire circumferential direction. The recess 24 extends in an arc shape on the longitudinal section of the rolling bearing 1. For example, on the longitudinal section of the rolling bearing 1, the radius of curvature of the recess 24 may be the same as the radius of curvature of the outer ring raceway surface 23, or may be different from the radius of curvature of the outer ring raceway surface 23. The recess 24 does not have to extend with a constant curvature on the longitudinal section of the rolling bearing 1. The recess 24 has an outward surface 24a that faces in a direction inclined outward in the axial direction with respect to the radial direction (radially inward and upward, or upward), and an inward surface 24b that faces in a direction inclined inward in the axial direction with respect to the radial direction (radially inward and downward, or downward). A portion of the inner circumferential surface 22b excluding the outer ring raceway surface 23 and the recess 24 extends in the axial direction with a constant inner diameter.

[0046] The inner peripheral surface 22b has a ridge portion 25 formed on the edge of the recess 24 on the outer ring raceway surface 23 side (axially inner side). The ridge portion 25 may be rounded or sharp on the vertical cross section of the rolling bearing 1.

[0047] The outer ring body 21 has a pair of inner circumferential surfaces 21a extending from the outer peripheral edge of each end face 22a of the protrusion 22 to the opening edge of the outer ring 20. The portion of each inner circumferential surface 21a located on the inside in the axial direction is located radially outward from the portion located on the outside in the axial direction.

[0048] The inner ring 10 is formed in an annular shape from a metal material such as stainless steel or bearing steel. However, the inner ring 10 is not limited to being made of metal, and may be formed from other materials. An inner ring raceway surface 11 is formed on the outer peripheral surface of the inner ring 10, recessed radially inward. The inner ring raceway surface 11 is formed in a hemispherical shape in cross section so as to follow the outer surface of the rolling element 30, and is formed in an annular shape extending in the circumferential direction around the entire circumference of the outer peripheral surface. The inner ring raceway surface 11 is formed on a portion of the outer peripheral surface of the inner ring 10 that is located at the center in the axial direction, and is disposed so as to face the outer ring raceway surface 23 in the radial direction. The portion of the outer peripheral surface of the inner ring 10 other than the inner ring raceway surface 11 extends in the axial direction with a constant outer diameter.

[0049] 2, the multiple rolling elements 30 are formed into a spherical shape from a metal material such as stainless steel or bearing steel. The multiple rolling elements 30 are disposed between the outer ring raceway surface 23 and the inner ring raceway surface 11, and are supported by the outer ring raceway surface 23 and the inner ring raceway surface 11 so as to be able to roll. The multiple rolling elements 30 are spaced apart in the circumferential direction by a cage 40.

[0050] The cage 40 is made of synthetic resin or metal material and is generally annular. The cage 40 is disposed about a common axis O. The cage 40 includes an annular portion 41 that is annular and disposed below the rolling elements 30, and a plurality of column portions 42 that protrude upward from the annular portion 41 and are disposed at intervals in the circumferential direction. The column portions 42 are uniformly arranged in the circumferential direction. A pair of column portions 42 adjacent to each other in the circumferential direction forms a ball pocket between them. The ball pocket penetrates the cage 40 in the radial direction and opens upward at the upper end surface of the cage 40. The ball pockets are provided in correspondence with the number of the rolling elements 30 and hold the rolling elements 30 so that they can roll individually. As a result, the cage 40 uniformly arranges the rolling elements 30 at intervals in the circumferential direction. The cage 40 is disposed with a gap from the inner ring 10 and the outer ring 20 so as not to interfere with the inner ring 10 and the outer ring 20. In this embodiment, the entire cage 40 is located axially inward of the pair of end faces 22 a of the protruding portion 22 of the outer ring 20 .

[0051] As shown in FIG. 1 and FIG. 2, the seal member 50 is formed in a circular plate shape. The seal member 50 is disposed around the common axis O. The seal member 50 is formed uniformly around the entire circumference. The seal member 50 is fitted into the outer ring 20 from the outside in the axial direction. The seal members 50 are disposed on both sides of the rolling elements 30 in the axial direction, one on each side. The seal member 50 has an annular seat portion 51 that contacts the outer ring 20 from the outside in the axial direction, an extension portion 52 that extends outward in the axial direction from the inner peripheral edge of the seat portion 51, a flat portion 53 that extends radially from the outer edge of the extension portion 52 in the axial direction toward the inner ring 10, and an engagement portion 54 that extends radially outward and axially outward from the outer peripheral edge of the seat portion 51.

[0052] As shown in FIG. 2, the seat portion 51 overlaps the end face 22a of the protruding portion 22 of the outer ring 20 from the outside in the axial direction. The seat portion 51 extends substantially parallel to the end face 22a of the protruding portion 22 of the outer ring 20. The seat portion 51 protrudes radially inward from the end face 22a of the protruding portion 22 in a plan view seen from the axial direction. The distance by which the seat portion 51 protrudes radially inward from the end face 22a of the protruding portion 22 is 10% or less, and preferably 5% or less, of the radial distance between the inner ring 10 and the outer ring 20. The extension portion 52 extends from the inner peripheral edge of the seat portion 51 outward in the axial direction and inward in the radial direction. The flat portion 53 overlaps the center of the rolling element 30 in a plan view. The inner peripheral edge of the flat portion 53 is disposed on the outer peripheral surface of the inner ring 10 with a gap therebetween. The surface of the flat portion 53 facing inward in the axial direction is a flat surface extending in the circumferential and radial directions. The outer peripheral edge of the locking portion 54 is locked to the inner peripheral surface 21a of the outer ring body 21 from the inside in the axial direction. As a result, the seal member 50 is fixed to the outer ring 20 and rotates integrally with the outer ring 20 relative to the inner ring 10.

[0053] Grease 60 is sealed in the rolling bearing 1. The grease 60 is disposed between the rolling element 30 and the seal member 50. The grease 60 is disposed on the same side of the annular space between the inner ring 10 and the outer ring 20 as the recess 24 with respect to the rolling element 30 in the axial direction. In this embodiment, the grease 60 is disposed on the opposite side of the rolling element 30 from the annular portion 41 of the cage 40 in the axial direction. The grease 60 is disposed above the rolling element 30. The grease 60 is disposed along the circumferential direction. The grease 60 extends in an annular or arc-like shape and is disposed coaxially with the common axis O.

[0054] The grease 60 includes an outer ring contact portion 61 in contact with the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20, and a seal member contact portion 62 in contact with the flat portion 53 of the seal member 50, axially outward and radially inward from the outer ring contact portion 61. The outer ring contact portion 61 and the seal member contact portion 62 extend in the circumferential direction over the entire length of the grease 60. The outer ring contact portion 61 has a width in the axial direction over the entire circumferential direction. The outer ring contact portion 61 contacts the recess 24 of the inner peripheral surface 22b of the protruding portion 22. The outer ring contact portion 61 contacts the recess 24 over the entire circumference. The outer ring contact portion 61 contacts the outward surface 24a of the recess 24. In this case, it is desirable that the outer ring contact portion 61 also contacts at least a part of the ridge portion 25. In this embodiment, the outer ring contact portion 61 contacts the ridge portion 25 over the entire circumference. Furthermore, the outer ring contact portion 61 contacts the inward surface 24b of the recess 24 and a portion of the recess 24 facing inward in the radial direction. In this embodiment, the outer ring contact portion 61 contacts the entire recess 24. It is desirable that the grease 60 does not contact any portion of the outer ring 20 other than the recess 24. That is, the outer ring contact portion 61 is provided at a distance in the axial direction from the contact portion between the outer ring 20 and the seat portion 51 of the seal member 50. The seal member contact portion 62 has a width in the radial direction over the entire circumferential direction. The seal member contact portion 62 contacts the flat portion 53 at a location that is spaced in the radial direction from the connection portion between the extension portion 52 and the flat portion 53 of the seal member 50.

[0055] The grease 60 extends axially outward and radially inward from the outer ring contact portion 61 toward the seal member contact portion 62. The grease 60 has an inner surface 63 and an outer surface 64. The inner surface 63 connects the axially inner edge of the outer ring contact portion 61 and the radially inner edge of the seal member contact portion 62. The inner surface 63 faces the outer peripheral surface of the inner ring 10 and the rolling elements 30. The upper half of the inner surface 63 extends axially inward and radially inward from the radially inner edge of the seal member contact portion 62. The lower half of the inner surface 63 extends axially outward and radially inward from the axially inner edge of the outer ring contact portion 61 and connects to the lower edge of the upper half. The boundary between the upper and lower halves of the inner surface 63 forms the inner peripheral edge of the grease 60 located at the innermost radial position. The inner surface 63 is separated from the inner ring 10, the rolling elements 30, and the cage 40. This prevents the grease 60 from contacting the inner ring 10, the rolling elements 30, and the cage 40.

[0056] The outer surface 64 connects the axially outer edge of the outer ring contact portion 61 and the radially outer edge of the seal member contact portion 62. The outer surface 64 faces the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20 and the seal member 50. The outer surface 64 extends axially inward and radially outward from the radially outer edge of the seal member contact portion 62 and connects to the axially outer edge of the outer ring contact portion 61. The outer surface 64 is separated from the seat portion 51 and the extension portion 52 of the seal member 50. As a result, the grease 60 is not in contact with the seat portion 51 and the extension portion 52 of the seal member 50, which are located closer to the outer ring 20 than the flat portion 53.

[0057] The grease 60 is formed so that the cross-sectional area of ​​the cross section along a plane perpendicular to the common axis O gradually increases from the axially outer end toward the axially inner side. In this embodiment, the grease 60 is formed in a portion corresponding to the upper half of the inner surface 63 so that the cross-sectional area of ​​the cross section along a plane perpendicular to the common axis O gradually increases from the axially outer end toward the axially inner side.

[0058] The grease 60 may come into contact with at least one of the rolling elements 30 and the cage 40. For example, the grease 60 may come into contact with at least one of the rolling elements 30 and the cage 40 due to changes over time, starting from an initial state in which the grease 60 is not in contact with the rolling elements 30 and the cage 40.

[0059] The following describes the composition of the grease 60. Note that the grease 60 may contain other components in addition to the base oil and the thickener, if necessary.

[0060] The base oil is not particularly limited, and examples thereof include mineral oil and synthetic oil. As the mineral oil, known mineral oils used as base oils can be used, and examples thereof include naphthenic mineral oil, paraffinic mineral oil, hydrogenated mineral oil, solvent refined mineral oil, and highly refined mineral oil. The mineral oil may be used alone or in combination of two or more. For example, a plurality of types of mineral oils may be mixed to adjust the desired properties.

[0061] As the synthetic oil, known synthetic oils used as base oils can be used, for example, poly-α-olefins (PAO), aliphatic hydrocarbon oils such as polybutene, aromatic hydrocarbon oils such as alkylbenzene and alkylnaphthalene, ester oils such as polyol ester and phosphate ester, ether oils such as polyphenyl ether, polyalkylene glycol oil, silicone oil, fluorine oil, etc. These synthetic oils may be used alone or in combination of two or more. For example, multiple types of synthetic oils may be mixed to adjust the desired properties.

[0062] The thickener plays a role in keeping the grease 60 in a semi-solid state. As the thickener, any known thickener that is normally used in greases for rolling bearings can be used without any restrictions. As the thickener, for example, a urea compound, lithium soap, calcium soap, composite lithium soap, composite calcium soap, silica gel, polytetrafluoroethylene, organo-bentonite, etc. can be mentioned. As the thickener, a urea compound is preferable in terms of excellent heat resistance. As the thickener, one type may be used alone, or two or more types may be used in combination. For example, a plurality of types of thickeners may be mixed to adjust the desired properties.

[0063] The unmixed penetration of the grease 60 of this embodiment is greater than 178 and less than 287. The difference between the worked penetration of the grease 60 and the unmixed penetration is preferably less than 50. The ratio of the difference between the worked penetration and the unmixed penetration to the worked penetration of the grease 60 is preferably less than 22.7%. The unmixed penetration of the grease 60 after being left at 85°C for 18 hours is preferably greater than 158. In the following description, leaving at 85°C for 18 hours is referred to as leaving at high temperature.

[0064] Next, a method for manufacturing the rolling bearing 1 of this embodiment will be described. The method for manufacturing the rolling bearing 1 of this embodiment includes a coating step and a sealing step.

[0065] 3 and 4 are vertical sectional views of a rolling bearing illustrating a grease application method according to the first embodiment. As shown in FIG. 3, the application process is performed in a state where the seal member 50 is not attached to the outer ring 20. That is, the grease 60 is applied in a state where the annular space between the inner ring 10 and the outer ring 20 is opened in the axial direction and the rolling elements 30 and the cage 40 are exposed. In the application process, the grease 60 is discharged from the nozzle A while rotating the nozzle A about the common axis O with respect to the outer ring 20. At this time, the direction of the nozzle A is adjusted so that the grease 60 is discharged from the nozzle A radially outward and axially inward. Furthermore, the position of the nozzle A is adjusted so that the discharged grease 60 contacts the recessed portion 24 of the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20 and the grease 60 does not contact the rolling elements 30 and the cage 40. Since the grease 60 is discharged while rotating the nozzle A relative to the outer ring 20, the grease 60 applied to the outer ring 20 extends in a circumferential or arc-like shape. The grease 60 is applied in a direction along which the grease 60 is discharged from the nozzle A so as to protrude axially outward and radially inward from the contact portion with the outer ring 20. The axially outer end face of the applied grease 60 is formed into a convex shape that bulges outward in the axial direction.

[0066] Next, the sealing process is performed. As shown in FIG. 4, in the sealing process, the seal member 50 is brought close to the outer ring 20 from the outside in the axial direction, and the seal member 50 is attached to the outer ring 20. In the process of displacing the seal member 50 inward in the axial direction, before the seat portion 51 comes into contact with the end face 22a of the protruding portion 22 of the outer ring 20, the flat portion 53 of the seal member 50 is first brought into contact with the axially outer end edge of the entire grease 60 (contact process). At this time, the grease 60 is brought into contact with the radially intermediate portion of the flat portion 53. Note that it is sufficient that the radially intermediate portion is located radially inward from the outer peripheral edge of the flat portion 53 and radially outward from the inner peripheral edge. Thereafter, the seal member 50 is brought even closer to the outer ring 20, and the seat portion 51 is brought into contact with the end face 22a of the protruding portion 22 of the outer ring 20 from the outside in the axial direction (attachment process). At this time, the flat portion 53 of the seal member 50 pushes the grease 60 inward in the axial direction. As a result, the grease 60 is pushed against the flat surface portion 53 and spreads in the radial direction, so that a seal member contact portion 62 of the grease 60 is formed.

[0067] In this manner, the rolling bearing 1 is formed. In the application step of this embodiment, the grease 60 is applied while the nozzle A is rotated relative to the outer ring 20, but the grease may be discharged from a nozzle having a discharge hole extending in the circumferential direction and applied all at once in a circumferential or arc-shaped manner.

[0068] As described above, in this embodiment, the rolling bearing 1 has the following configuration. The inner peripheral surface 22b of the protruding portion 22 of the outer ring 20 is provided with an outer ring raceway surface 23 that supports the rolling element 30 so as to be able to roll, and a recess 24 that is provided at a location extending in the axial direction from the axial end edge of the outer ring raceway surface 23 and recessed in the radial direction. The grease 60 is in contact with the recess 24. According to this configuration, the recess 24 can restrict the grease 60 from being displaced in the axial direction. This can prevent the grease 60 from being displaced and coming into contact with the rolling element 30 or the cage 40 in an amount greater than the desired amount. This can reduce the rotational resistance of the rolling bearing 1. Furthermore, since the grease 60 can be arranged inside the recess 24, the total amount of grease 60 can be increased compared to a configuration in which no recess is formed.

[0069] Here, the grease 60 is disposed between the rolling elements 30 and the seal member 50, and most (or the entirety) of the grease 60 is not in contact with the rolling elements 30 and the cage 40. In other words, the portion of the grease 60 that is in contact with the rolling elements 30 or the cage 40 and is subjected to shear stress when the rolling bearing 1 is in operation is small, and there are cases in which the grease 60 is not in contact with the rolling elements 30 and the cage 40.

[0070] The hardness of the grease differs between a state where it is not subjected to shear (a state where it is not mixed) and a state where it is subjected to shear (a state where it is mixed). Generally, grease becomes soft when it is subjected to shear. For this reason, the portion of the grease 60 that contacts the inner ring 10, the rolling element 30, or the cage 40 continues to receive shear from the rolling element 30 or the cage 40 and becomes soft, promoting the seepage of the base oil. On the other hand, the portion of the grease 60 that does not contact the rolling element 30 or the cage 40 remains hard. When only a small portion of the grease 60 contacts the rolling element 30 or the cage 40, if there is insufficient base oil seeping out from the portion that is subjected to shear by the rolling element 30 or the cage 40, most of the grease 60 is not stirred and remains hard, resulting in an insufficient supply of base oil, which leads to the end of the life of the rolling bearing 1. The same applies when the entire grease 60 is not in contact with the rolling element 30 or the cage 40.

[0071] Incidentally, there are worked penetration and unworked penetration as indicators of properties related to the hardness of a grease. Worked penetration is an indicator of the hardness of a grease immediately after it has been subjected to shear. Therefore, the state of the grease when the worked penetration is measured is close to the state of the portion of the grease that is in contact with the rolling elements or the cage in a rolling bearing and is subjected to shear. On the other hand, unworked penetration is an indicator of the hardness of the grease in a state that is not subjected to shear. Therefore, the state of the grease when the unworked penetration is measured is close to the state of the portion of the grease that is not in contact with the rolling elements or the cage in a rolling bearing.

[0072] In this embodiment, the unmixed penetration of the grease 60 is greater than 178 and less than 287. According to this configuration, the portion of the grease 60 that is not in contact with the rolling body 30 and the cage 40 is relatively soft and is in a state where the oil is easily separated to the outside. Therefore, even if the base oil in the portion of the grease 60 that is in contact with the rolling body 30 or the cage 40 is about to run short, the base oil seeps out from the inside of the grease 60 that is not in contact with the rolling body 30 and the cage 40, and the base oil can be continuously supplied to the sliding part. In addition, even if the grease 60 is applied in a state where it does not come into contact with the rolling body 30 and the cage 40, the base oil can be supplied to the sliding part from the surface of the grease 60, and the base oil can be supplied to the sliding part from the inside of the grease 60 by seeping out to the surface of the grease 60. Therefore, even if the grease 60 is placed away from the rolling elements 30 and the retainer 40 in order to reduce the rotational resistance of the rolling bearing 1, the base oil can be supplied to the sliding parts for a long period of time, thereby improving the durability of the rolling bearing 1.

[0073] Furthermore, by having an unmixed penetration of less than 287, excessive deformation of the grease 60 due to sagging or dragging caused by gravity can be suppressed, and the shape of the portions of the grease 60 that are not in contact with the rolling elements 30 and the cage 40 can be maintained in their initial shape. This makes it possible to suppress variations in the shape of the grease 60 for each rolling bearing 1, which would otherwise cause variations in the rotational resistance. As a result, it is possible to provide a rolling bearing 1 that can ensure durability and reduce rotational resistance at the same time.

[0074] Furthermore, in this embodiment, the grease 60 contacts both the inner peripheral surface of the outer ring 20 and the seal member 50. In this configuration, when the grease 60 is filled between the outer ring 20 and the inner ring 10, the grease 60 is applied to the outer ring 20, and then when the seal member 50 is attached to the outer ring 20, the grease 60 is pushed axially inward by the seal member 50. Here, in the case of a grease having a relatively small (hard) immiscible penetration as in the past, when the grease is pushed axially inward by the seal member, although there is a slight deformation, the entire grease may move axially inward and contact the rolling element 30 or the cage 40 more than desired. In this embodiment, since the immiscible penetration of the grease 60 is relatively large (soft), the grease 60 is easily deformed in the radial direction when it is pushed axially inward by the seal member 50, and the movement of the grease 60 in the axial direction inward is suppressed, and the grease 60 can be suppressed from contacting the rolling element 30 or the cage 40 more than necessary. Therefore, an increase in the rotational resistance of the rolling bearing 1 can be suppressed.

[0075] The grease 60 is in contact with the outward surface 24a of the recess 24, which faces in a direction inclined axially outward with respect to the radial direction. With this configuration, the outward surface 24a of the recess 24 restricts the grease 60 from displacing axially inward from the initial state. As a result, the grease 60 is less likely to displace axially inward from its initial position as the rolling bearing 1 is used over time, so that the amount of grease 60 enclosed can be increased, and the above-mentioned effects can be obtained more reliably.

[0076] Furthermore, because the grease 60 contacts the outward surface 24a of the recess 24, the shape and position of the grease 60 are unlikely to change due to vibration during transportation or long-term storage (particularly storage in a high-temperature environment). Therefore, it is possible to provide a rolling bearing 1 in which fluctuations in rotational resistance from the initial manufacturing stage are suppressed.

[0077] The recess 24 has an inward surface 24b that faces in a direction inclined axially inward with respect to the radial direction. With this configuration, the inward surface 24b of the recess 24 restricts the grease 60 from displacing axially outward. This makes it possible to prevent the grease 60 or its base oil from flowing out toward the seal member 50 and leaking from the gap between the seal member 50 and the outer ring 20.

[0078] Particularly in this embodiment, since the grease 60 contacts the outward surface 24a of the recess 24, the grease 60 is supported not only by the recess 24 but also by the seal member 50. For this reason, the shape and position of the grease 60 are less likely to change due to vibration during transportation or long-term storage (particularly storage in a high-temperature environment). Therefore, it is possible to provide a rolling bearing 1 in which fluctuations in rotational resistance from the initial manufacturing stage are suppressed.

[0079] Moreover, since the grease 60 contacts the extension portion 52 and the flat portion 53 of the seal member 50, it is easy to achieve the effect of suppressing changes in the shape and position of the grease 60. Also, since it is possible to increase the amount of grease 60, it is possible to impart higher durability to the rolling bearing 1. Note that the above effect is achieved when the grease 60 contacts at least one of the extension portion 52 and the flat portion 53 of the seal member 50. However, it is more preferable that the grease 60 contacts the flat portion 53.

[0080] The grease 60 is in contact with the seal member 50. According to this configuration, even if the grease 60 in contact with the seal member 50 is pushed axially inward by the seal member 50 when the seal member 50 is attached to the outer ring 20 with the grease 60 applied to the outer ring 20, the recesses 24 restrict the grease 60 from displacing axially inward as described above, and therefore the grease 60 can be prevented from contacting the rolling elements 30 or the cage 40 by more than a desired amount. Therefore, the rotational resistance of the rolling bearing 1 can be reduced.

[0081] The grease 60 also contacts the ridge portion 25 formed on the edge of the recess 24 on the outer ring raceway surface 23 side. With this configuration, the base oil that seeps out of the grease 60 does not need to climb over the ridge portion 25 on the way to the outer ring raceway surface 23, so that a shortage of the base oil of the grease 60 supplied to the rolling elements 30 can be suppressed.

[0082] The grease 60 has an outer ring contact portion 61 that contacts the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20, and a seal member contact portion 62 that contacts the flat portion 53 of the seal member 50 on the axially outer side and the radially inner side of the outer ring contact portion 61. The area of ​​the seal member contact portion 62 is larger than the contact area between the grease 60 and the extension portion 52 and the base portion 51 of the seal member 50. According to this configuration, when the seal member 50 is attached after the grease 60 is applied to a predetermined location, a space can be provided for the grease 60 pushed axially inward by the flat portion 53 of the seal member 50 to spread radially toward the extension portion 52 and the base portion 51. Therefore, it is possible to prevent the grease 60 from spreading significantly toward the inner ring 10 side and the rolling element 30 side. Therefore, it is possible to easily prevent the grease 60 from directly contacting the rolling element 30 and the cage 40. Moreover, since the sealing member 50 has the extension portion 52 between the flat portion 53 and the base portion 51, the grease 60 can be disposed at a position farther away from the rolling element 30 than in a configuration in which the flat portion extends radially inward from the base portion. Therefore, the amount of grease 60 can be increased. As a result, it is possible to provide a rolling bearing 1 that can ensure durability and reduce rotational resistance at the same time.

[0083] The grease 60 is not in contact with the extension portion 52. With this configuration, when the seal member 50 is attached, it is possible to provide a larger space for the grease 60, which is pushed axially inward by the flat portion 53 of the seal member 50, to spread radially toward the extension portion 52. This makes it possible to prevent the grease 60 from spreading significantly toward the inner ring 10 and the rolling elements 30. This makes it possible to easily prevent the grease 60 from coming into contact with the rolling elements 30, the cage 40, and the inner ring 10 more than necessary.

[0084] In addition, because the difference between the worked and unworked penetration of the grease 60 is less than 50, the softness of the portions of the grease 60 that are not in contact with the rolling elements 30 and the cage 40 becomes close to the softness of the portions of the grease 60 that are in contact with the rolling elements 30 and the cage 40. This reduces the difference in the degree of seepage of the base oil between the portions of the grease 60 that are in contact with the rolling elements 30 or the cage 40 and the portions that are not in contact with the rolling elements 30 and the cage 40. Therefore, the rotational resistance of the rolling bearing 1 can be stabilized over a long period of time.

[0085] In addition, since the ratio of the difference between the worked penetration and the unworked penetration to the worked penetration of the grease 60 is less than 22.7%, the softness of the portions of the grease 60 that are not in contact with the rolling elements 30 and the cage 40 becomes close to the softness of the portions of the grease 60 that are in contact with the rolling elements 30 or the cage 40. This reduces the difference in the degree of seepage of the base oil between the portions of the grease 60 that are in contact with the rolling elements 30 or the cage 40 and the portions that are not in contact with the rolling elements 30 and the cage 40. Therefore, the rotational resistance of the rolling bearing 1 can be stabilized over a long period of time.

[0086] The thickener of the grease 60 contains urea. With this configuration, a grease with high heat resistance can be obtained, making it possible to form a rolling bearing 1 with low rotation resistance and high durability. Generally, in greases using urea as a thickener, the difference between the mixed and unmixed penetrations tends to be large, but by selecting the type of urea, mixing multiple types of urea, adjusting the urea production conditions, additives, etc., it is possible to obtain a grease that satisfies the above-mentioned penetration conditions.

[0087] Since the unmixed penetration of the grease 60 after being left at 85°C for 18 hours is greater than 158, the degree of hardening of the grease 60 can be set to such an extent that the base oil can smoothly seep out even if the grease 60 is exposed to high temperatures or left for a long period of time. Therefore, a rolling bearing 1 with high durability can be formed.

[0088] Furthermore, the rotating device 2 of this embodiment is equipped with the rolling bearing 1 that ensures durability and reduces rotational resistance, so that it is possible to achieve a longer life for the rotating device 2 and to achieve power savings for the rotating device 2 by reducing the rotational resistance of the shaft 3 relative to the housing 4.

[0089] In the first embodiment, the recess 24 extends in a curved shape on the longitudinal section of the rolling bearing 1, but is not limited to this configuration. As shown in FIG. 5, the recess 24A may be formed to define a rectangular space on the longitudinal section of the rolling bearing 1. That is, the recess 24A includes a bottom surface 24Aa extending in the axial direction, a first step surface 24Ab extending radially inward from the axially inner edge of the bottom surface 24Aa and facing upward, and a second step surface 24Ac extending radially inward from the axially outer edge of the bottom surface 24Aa and facing downward. In this case, the grease 60 is restricted from displacing axially inward from the initial state by contacting the first step surface 24Ab, so that the same effect as the first embodiment is achieved. Also, the grease 60 is restricted from displacing axially outward by contacting the second step surface 24Ac, so that the same effect as the first embodiment is achieved. In this modified example, it is also preferable that the grease 60 contacts the ridge portion 25A formed on the edge of the recess 24A on the outer ring raceway surface 23 side (axially inner side).

[0090] In the first embodiment, the recess 24 is open only to the inner circumferential surface 22b, but the present invention is not limited to this configuration. As shown in FIG. 6, the recess 24B may be provided without an axial gap from the end face 22a facing upward, and may be open to the inner circumferential surface 22b and the end face 22a facing upward. In the illustrated example, the recess 24B has an outward surface 24Ba facing in a direction inclined axially outward with respect to the radial direction (inward in the radial direction and upward, or upward), and a cylindrical surface 24Bc facing inward in the radial direction. The grease 60 is in contact with the outward surface 24Ba and the cylindrical surface 24Bc. Note that, in this modified example, it is also desirable that the grease 60 is in contact with the ridge portion 25B formed on the end edge of the recess 24B on the outer ring raceway surface 23 side (inward in the axial direction).

[0091] Furthermore, as shown in FIG. 7, the grease 60 may be in contact with the seal member 50 through an opening on the end face 22a of the recess 24B. In the illustrated example, the grease 60 is in contact with the base portion 51 of the seal member 50 arranged so as to close the opening on the end face 22a of the recess 24B. However, the grease 60 may be in contact with the extension portion 52 and the flat portion 53 in addition to the base portion 51. In this case, the grease 60 may not be in contact with the ridge portion 25B, or may be in contact with the ridge portion 25B. Also, the grease 60 is in contact with only the cylindrical surface 24Bc of the recess 24B. However, the grease 60 may be in contact with the outward surface 24Ba in addition to the cylindrical surface 24Bc.

[0092] Also, as shown in FIG. 8, the recess 124 may be formed so that the entire recess 124 faces a direction inclined toward the outside in the axial direction with respect to the radial direction (inward in the radial direction and upward, or upward). That is, the recess 124 may not have a portion extending in the axial direction. In the illustrated example, the recess 124 has an inclined surface 124a extending from a ridge portion 25C formed on the end edge on the outer ring raceway surface 23 side (inner in the axial direction) to an opening edge on the end face 22a. The inclined surface 124a extends from the ridge portion 25C toward the outside in the radial direction and the axial direction. In the illustrated example, the inclined surface 124a is a concave curved surface that is continuous over the entirety. However, the inclined surface may be formed of a plurality of discontinuous surfaces as long as it extends in a direction inclined toward the axial direction from the ridge portion 25C, and may be a conical surface extending at a constant inclination angle with respect to the axial direction. Furthermore, a part of the inclined surface may extend along the radial direction.

[0093] In the modified example shown in FIG. 8, the grease 60 contacts from the inclined surface 124a to the ridge 25C. Furthermore, in this modified example, the grease 60 also contacts the inner circumferential surface of the protruding portion 22 of the outer ring 20 at a location between the ridge 25C and the outer ring raceway surface 23. That is, the grease 60 contacts from a location between the ridge 25C and the outer ring raceway surface 23 to the inclined surface 124a so as to axially overcome the ridge 25C. With this configuration, the base oil exuded from the grease 60 does not need to overcome the ridge 25C in the process of reaching the outer ring raceway surface 23, so that the supply of the base oil of the grease 60 to the rolling element 30 can be suppressed from being insufficient. Note that in this modified example, as in the third modified example shown in FIG. 7, the grease 60 contacts the seal member 50 through the opening on the end face 22a of the recess 124. However, in this modified example, the grease 60 may not contact the seal member 50.

[0094] In the first embodiment, the recess 24 extends continuously in the entire circumferential direction, but is not limited to this configuration. The recess may be discontinuous in the circumferential direction so that an intermittent portion is formed in at least a part of the circumferential direction.

[0095] In the first embodiment, the seat 51 of the seal member 50 protrudes radially inward from the end face 22a of the protruding portion 22 of the outer ring 20 in plan view, but it is preferable that the seat is arranged so as not to protrude radially inward from the end face 22a of the protruding portion 22 in plan view. With this configuration, even if the outer ring contact portion 61 of the grease 60 spreads outward in the axial direction and overcomes the inner peripheral edge of the end face 22a, the grease 60 can be prevented from adhering to the seat. Therefore, the grease 60 can be prevented from contacting the contact portion between the outer ring 20 and the seat. This can prevent the grease 60 from leaking out of the seal member due to capillary action through the contact portion between the outer ring 20 and the seat.

[0096] In the first embodiment, the grease 60 is not in contact with the base portion 51 and the extension portion 52 of the seal member 50, but this is not limiting. The grease may be in contact with at least one of the base portion 51 and the extension portion 52 of the seal member 50, and the above-mentioned effects are achieved as long as the area of ​​the seal member contact portion is larger than the area of ​​contact between the grease and the extension portion 52 and the base portion 51.

[0097] As a method of fixing the seal member 50, in addition to the method of press-fitting and fixing it to the raceway (outer ring 20) as in this embodiment, there is also a method of fixing the raceway from the outside in the axial direction with a retaining ring such as a C-ring, but this is not preferable because the position of the seal member 50 is closer to the inside in the axial direction. By press-fitting and fixing the seal member 50, the seal member 50 can be positioned further outward in the axial direction, and the amount of grease 60 can be increased. In addition, since the recesses 24 can be provided further outward in the axial direction, even if the grease 60 is applied to the recesses 24, the grease 60 is less likely to get caught in the rolling elements 30 and the raceway surface, and the rotational resistance of the rolling bearing can be reduced.

[0098] [Second embodiment] Next, a second embodiment will be described with reference to Fig. 9. The second embodiment differs from the first embodiment in that the rolling bearing 1A includes grease 160 instead of the grease 60 of the first embodiment. Note that the configuration other than that described below is the same as that of the first embodiment.

[0099] FIG. 9 is a vertical sectional view of the rolling bearing according to the second embodiment. As shown in FIG. 9, the grease 160 is disposed along the circumferential direction. The grease 160 extends in an annular shape and is disposed coaxially with the common axis O. The grease 160 has an outer ring contact portion 161 that contacts the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20, and is not in contact with the inner ring 10, the seal member 50, the rolling element 30, and the cage 40. The outer ring contact portion 161 extends in the circumferential direction over the entire length of the grease 160. The outer ring contact portion 161 has a width in the axial direction over the entire circumferential direction. The outer ring contact portion 161 contacts the recessed portion 24 of the inner peripheral surface 22b of the protruding portion 22. It is desirable that the grease 160 also contacts at least a part of the ridge portion 25. In this embodiment, the outer ring contact portion 61 contacts the ridge portion 25 over the entire circumference. The outer ring contact portion 161 is provided axially spaced from the contact portion between the outer ring 20 and the seat portion 51 of the seal member 50 .

[0100] This embodiment provides the same effects as the first embodiment. In addition, in this embodiment, since the grease 160 does not contact the seal member 50, the grease 160 is not pressed by the seal member 50 when the seal member 50 is attached to the outer ring 20. This makes it possible to suppress the grease 160 from moving axially inward and to suppress the grease 160 from coming into contact with the rolling elements 30 or the cage 40 more than necessary. Therefore, it is possible to suppress an increase in the rotational resistance of the rolling bearing 1A.

[0101] In the second embodiment, the grease 160 extends in an annular shape, but is not limited to this configuration. The grease may extend in an arc shape to form intermittent portions, or may have a plurality of granules arranged in dots around the entire circumference. When the grease has a plurality of granules, the granules aligned in the circumferential direction may be integrated or may be spaced apart from each other.

[0102] [Third embodiment] Next, a third embodiment will be described with reference to Fig. 10. The rolling bearing 1B of the third embodiment differs from the rolling bearing 1A of the second embodiment in that the grease 160A is in contact with the seal member 50 and the rolling elements 30. Note that the configuration other than that described below is the same as that of the second embodiment.

[0103] FIG. 10 is a vertical sectional view of a rolling bearing according to the third embodiment. As shown in FIG. 10, the grease 160A further includes a seal member contact portion 162 that contacts the flat portion 53 of the seal member 50 axially outward and radially inward from the outer ring contact portion 161, and is not in contact with the inner ring 10. The seal member contact portion 162 contacts only the flat portion 53 of the seal member 50. As a result, the grease 160A is not in contact with the seat portion 51 and the extension portion 52 that are located on the outer ring 20 side of the flat portion 53 of the seal member 50. The grease 160A contacts the rolling element 30. The volume of the portion of the grease 160A that contacts the rolling element 30 is half or less of the entire volume of the grease 160A. The grease 160A may be in contact with the cage 40.

[0104] This embodiment provides the same effects as those of the second embodiment. In addition, in this embodiment, since the grease 160A contacts the rolling elements 30, the base oil of the grease 160A can be directly supplied to the rolling elements 30. Therefore, an increase in the rotational resistance of the rolling bearing 1B can be suppressed.

[0105] In the third embodiment, similarly to the first embodiment, the grease 160A is prevented from spreading significantly toward the inner ring 10 and the rolling elements 30 when the seal member 50 is attached. Therefore, even if the grease 160A contacts the rolling elements 30, the contact area can be made sufficiently smaller than in the conventional structure, and the effect of reducing the rotational resistance can be obtained.

[0106] In the third embodiment, the grease 160A extends in an annular shape, but is not limited to this configuration. The grease may extend in an arc shape to form intermittent portions, or may have a plurality of granules arranged in dots around the entire circumference. When the grease has a plurality of granules, the granules aligned in the circumferential direction may be integrated or may be spaced apart from each other.

[0107] [Fourth embodiment] Next, a fourth embodiment will be described. The grease contacts only a portion of the recess, which faces in a direction inclined axially outward from the radial direction (radially inward and upward, or upward), and which is continuous with the ridge. For example, if the recess has a bottom surface extending in the axial direction, the grease contacts only a portion of the recess between the ridge and the bottom surface. It is preferable that the grease contacts the seal member. This allows the grease to be sandwiched between the seal member and the recess from both sides in the axial direction, and allows the initial shape to be maintained for a long period of time.

[0108] [Fifth embodiment] Next, a fourth embodiment will be described with reference to Fig. 11. The rolling bearing 1C of the fourth embodiment differs from the rolling bearing 1 of the first embodiment in that the grease 260 is in contact only with the outward surface 24Ca of the recess 24C. Note that the configuration other than that described below is the same as that of the first embodiment.

[0109] FIG. 11 is a vertical sectional view of a rolling bearing according to a fifth embodiment. As shown in FIG. 11, a recess 24C recessed radially outward is formed on the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20. The recess 24C is provided without any space in the axial direction from the end surface 22a of the protruding portion 22 facing upward, and opens to the inner peripheral surface 22b and the end surface 22a facing upward. The recess 24C has an outward surface 24Ca facing in a direction inclined axially outward with respect to the radial direction (radially inward and upward, or upward), and a cylindrical surface 24Cc facing radially inward. The outward surface 24Ca is a concave curved surface. The cylindrical surface 24Cc extends in the axial direction, and is smoothly connected to the outward surface 24Ca at the axially inner end edge so that the tangent is continuous.

[0110] The grease 260 includes an outer ring contact portion 261 (raceway contact portion) in contact with the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20, and a seal member contact portion 262 in contact with the seal member 50 on the axially outer side and radially inner side of the outer ring contact portion 261. The outer ring contact portion 261 is in contact with the recessed portion 24C of the inner peripheral surface 22b of the protruding portion 22. The outer ring contact portion 261 is in contact with the recessed portion 24C over the entire circumference. The outer ring contact portion 261 is in contact only with the outward surface 24Ca of the recessed portion 24C. In this case, it is desirable that the outer ring contact portion 261 is also in contact with at least a part of the ridge portion 25 of the inner peripheral surface 22b. However, the outer ring contact portion 261 does not have to be in contact with the ridge portion 25 of the inner peripheral surface 22b. In this embodiment, the seal member contact portion 262 is a portion of the grease 260 that is in contact with the flat portion 53 of the seal member 50. In this embodiment, the grease 260 also contacts the base portion 51 and the extension portion 52 of the seal member 50. However, when the grease 260 contacts at least one of the base portion 51 and the extension portion 52 of the seal member 50, it is desirable that the area of ​​the seal member contact portion 262 is larger than the contact area of ​​the grease 260 with the extension portion 52 and the base portion 51. Note that the grease 260 may not contact at least one of the base portion 51 and the extension portion 52. The grease 260 is formed so that the cross-sectional area of ​​the cross section along the perpendicular plane of the common axis O gradually increases from the end portion on the outer side in the axial direction toward the inner side in the axial direction.

[0111] The grease 260 includes a first annular portion 260a in contact with the outer ring 20, and a second annular portion 260b that is continuous with the first annular portion 260a and is in contact with the seal member 50. The first annular portion 260a and the second annular portion 260b are formed by applying the grease twice. The first annular portion 260a and the second annular portion 260b each extend circumferentially about a common axis O. However, at least one of the first annular portion 260a and the second annular portion 260b may extend less than 360° about the common axis O. The first annular portion 260a includes an outer ring contact portion 261. The second annular portion 260b is disposed on the opposite side of the first annular portion 260a from the outer ring 20 in the radial direction (i.e., on the inside in the radial direction). The second annular portion 260b is connected to and integrated with the first annular portion 260a on the outer side in the axial direction.

[0112] This embodiment has the same effects as the first embodiment. In addition, in this embodiment, the recess 24C opens to the end face 22a of the protrusion 22 facing upward, and the grease 260 contacts only the outward surface 24Ca of the recess 24C. This configuration makes it possible to prevent the grease 260 or its base oil from flowing out from the recess 24C to the end face 22a side and leaking from the gap between the end face 22a and the seat portion 51 of the seal member 50.

[0113] In the fifth embodiment, the first annular portion 260a and the second annular portion 260b extend circumferentially, but are not limited to this configuration. At least one of the first annular portion and the second annular portion may have granules arranged in a dot pattern around the entire circumference. In this case, the granules aligned in the circumferential direction may be integrated or may be spaced apart from each other.

[0114] In the fifth embodiment, the grease 260 has the first annular portion 260a and the second annular portion 260b, but is not limited to this configuration. As shown in Fig. 12, the grease 260A may be formed of a single annular portion having the outer ring contact portion 261 and the seal member contact portion 262.

[0115] [Sixth embodiment] Next, a sixth embodiment will be described with reference to Fig. 13. A rolling bearing 1D of the sixth embodiment differs from the rolling bearing 1 of the first embodiment in that grease 360 ​​is arranged in the axial direction along the recess 24D. Note that the configuration other than that described below is the same as that of the first embodiment.

[0116] FIG. 13 is a vertical sectional view of a rolling bearing according to the sixth embodiment. As shown in FIG. 13, a recess 24D recessed radially outward is formed on the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20. The recess 24D is provided without any space in the axial direction from the end surface 22a of the protruding portion 22 facing upward, and opens to the inner peripheral surface 22b and the end surface 22a facing upward. The recess 24D has an outward surface 24Da facing in a direction inclined axially outward with respect to the radial direction (radially inward and upward, or upward), and a cylindrical surface 24Dc facing radially inward. The outward surface 24Da is a concave curved surface. The cylindrical surface 24Dc extends in the axial direction, and is smoothly connected to the outward surface 24Da at the axially inner end edge so that the tangent is continuous. The recess 24D extends in the axial direction so that the axial width is larger than the radial depth on the longitudinal section of the rolling bearing 1D. The outward surface may be a flat surface facing axially outward, or a conical surface facing axially outward and radially inward.

[0117] The grease 360 ​​has an outer ring contact portion 361 that contacts the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20. The outer ring contact portion 361 contacts the recessed portion 24D of the inner peripheral surface 22b of the protruding portion 22. The outer ring contact portion 361 contacts the recessed portion 24D over the entire circumference. The outer ring contact portion 361 contacts the outward surface 24Da and the cylindrical surface 24Dc of the recessed portion 24D. The outer ring contact portion 361 also contacts at least a portion of the ridge portion 25 of the inner peripheral surface 22b. The grease 360 ​​contacts the seal member 50. In this embodiment, the grease 360 ​​contacts the seat portion 51 and the extension portion 52 of the seal member 50.

[0118] The grease 360 ​​is disposed in the axial direction along the recess 24D on the longitudinal section of the rolling bearing 1D. The grease 360 ​​includes a first annular portion 360a, a second annular portion 360b, and a third annular portion 360c aligned in the axial direction. The first annular portion 360a, the second annular portion 360b, and the third annular portion 360c are formed by applying the grease three times. The first annular portion 360a, the second annular portion 360b, and the third annular portion 360c each extend circumferentially around the common axis O. However, at least one of the first annular portion 360a, the second annular portion 360b, and the third annular portion 360c may extend less than 360° around the common axis O. The first annular portion 360a is in contact with the outward surface 24Da and the cylindrical surface 24Dc of the recess 24D. The second annular portion 360b is connected to the first annular portion 360a on the outside in the axial direction. The second annular portion 360b is in contact with the cylindrical surface 24Dc of the recess 24D. The third annular portion 360c is connected to the second annular portion 360b on the outside in the axial direction. The third annular portion 360c is in contact with the cylindrical surface 24Dc of the recess 24D and the seal member 50.

[0119] This embodiment achieves the same effects as the first embodiment. In addition, in this embodiment, since the grease 360 ​​is arranged in the axial direction along the recess 24D, the recess 24D can effectively restrict the grease 360 ​​from being displaced in the axial direction, and the grease 360 ​​can be prevented from being displaced and coming into contact with the rolling elements 30 or the cage 40 in an amount greater than the desired amount. Furthermore, the shape and position of the grease 360 ​​are unlikely to change due to vibration during transportation or long-term storage (especially storage in a high-temperature environment). Therefore, it is possible to provide a rolling bearing 1D in which fluctuations in rotational resistance from the initial manufacturing stage are suppressed.

[0120] In the sixth embodiment, the first annular portion 360a, the second annular portion 360b, and the third annular portion 360c extend circumferentially, but are not limited to this configuration. At least one of the first annular portion, the second annular portion, and the third annular portion may have granules arranged in a dot pattern around the entire circumference. In this case, the granules aligned in the circumferential direction may be integrated or may be spaced apart from each other.

[0121] In the sixth embodiment, the grease 360 ​​has the first annular portion 360a, the second annular portion 360b, and the third annular portion 360c, but is not limited to this configuration. As shown in Fig. 14, the grease 360A may extend in the axial direction along the recess 24D on the vertical cross section of the rolling bearing 1D.

[0122] In the sixth embodiment, the grease 360 ​​contacts the ridge portion 25 of the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20, but the present invention is not limited to this configuration. As shown in FIG. 15, the grease 360B may not contact the ridge portion 25. In this case, the first annular portion 360a may be formed smaller than the second annular portion 360b and the third annular portion 360c on the vertical cross section of the rolling bearing 1D so as not to contact the ridge portion 25. According to this configuration, the supply of the base oil of the grease 360B to the rolling element 30 may be insufficient, but the total amount of the grease 360B can be increased to impart higher durability to the rolling bearing 1D.

[0123] [Seventh embodiment] Next, a seventh embodiment will be described with reference to Fig. 16. The rolling bearing 1E of the seventh embodiment differs from the rolling bearing 1 of the first embodiment in that the deepest portion in the radial direction of the recess 24E is formed axially inward of the axial middle position of the recess 24E. Note that the configuration other than that described below is the same as that of the first embodiment.

[0124] FIG. 16 is a vertical sectional view of a rolling bearing according to the seventh embodiment. As shown in FIG. 16, the recess 24E is provided with an axial gap from the outer ring raceway surface 23. The recess 24E is provided with an axial gap from the end face 22a facing upward. The recess 24E is formed so that its axial width is greater than its radial depth on the longitudinal section of the rolling bearing 1E. The recess 24E includes an outward surface 24Ea facing in a direction inclined outward in the axial direction with respect to the radial direction (radially inward and upward, or upward), an inward surface 24Eb facing in a direction inclined inward in the axial direction with respect to the radial direction (radially inward and downward, or downward), and a cylindrical surface 24Ec facing inward in the radial direction. In this embodiment, the outward surface 24Ea and the inward surface 24Eb face in the axial direction. As a result, the recess 24E is formed in a rectangular shape on the longitudinal section of the rolling bearing 1E. The cylindrical surface 24Ec is located at the deepest position in the radial direction of the recess 24E and axially straddles the axial middle position of the recess 24E. As a result, the deepest part in the radial direction of the recess 24E is formed axially inward of the axial middle position of the recess 24E.

[0125] The grease 460 includes an outer ring contact portion 461 (raceway contact portion) in contact with the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20, and a seal member contact portion 462 in contact with the flat portion 53 of the seal member 50 on the axially outer side and radially inner side of the outer ring contact portion 461. The outer ring contact portion 461 is in contact with the recess 24E of the inner circumferential surface 22b of the protruding portion 22. The outer ring contact portion 461 is in contact with the recess 24E over the entire circumference. The outer ring contact portion 461 is in contact with the outward surface 24Ea and the cylindrical surface 24Ec of the recess 24E. The outer ring contact portion 461 is also in contact with at least a part of the ridge portion 25 of the inner circumferential surface 22b. The grease 460 is not in contact with the inward surface 24Eb of the recess 24E. However, the grease 460 may be in contact with the inward surface 24Eb of the recess 24E. In this embodiment, the seal member contact portion 462 is a portion of the grease 460 that contacts the flat portion 53 of the seal member 50. In this embodiment, the grease 460 is not in contact with the base portion 51 and the extension portion 52 of the seal member 50. However, the grease 460 may be in contact with at least one of the base portion 51 and the extension portion 52 of the seal member 50. In this case, it is desirable that the area of ​​the seal member contact portion 462 is larger than the area of ​​contact between the grease 260 and the extension portion 52 and the base portion 51. The grease 460 extends from the outer ring contact portion 461 toward the seal member contact portion 462, axially outward and radially inward.

[0126] In this embodiment, the same effect as in the first embodiment is achieved. In addition, in this embodiment, the deepest part of the recess 24E in the radial direction is formed axially inward from the axial middle position of the recess 24E. According to this configuration, when the grease 460 is discharged from the nozzle and applied to a predetermined location, the tip of the nozzle can be easily inserted from the outside of the rolling bearing 1E to the inside of the outer ring 20 and the inner ring 10 to approach the recess 24E. Therefore, the productivity of the small-diameter rolling bearing 1E can be improved. In addition, since the nozzle can be easily brought close to the recess 24E, the grease 460 can be applied with high precision, and the grease 460 can be prevented from contacting the rolling element 30 or the like in an amount greater than the desired amount. Therefore, the rotational resistance of the rolling bearing 1E can be reduced.

[0127] In the seventh embodiment, the recesses 24E are formed symmetrically in the vertical direction on the vertical cross section of the rolling bearing 1E, but are not limited to this configuration. As shown in Figures 17 and 18, the recesses 124E, 224E may be formed asymmetrically in the vertical direction on the vertical cross section of the rolling bearing 1E. Below, the modified examples shown in Figures 17 and 18 will be described.

[0128] In the first modified example shown in FIG. 17, the recess 124E is formed so that the axial width is larger than the radial depth on the longitudinal section of the rolling bearing 1E. The recess 124E has an outward surface 124Ea that faces in a direction inclined axially outward with respect to the radial direction (radially inward and upward, or upward), and an inward surface 124Eb that faces in a direction inclined axially inward with respect to the radial direction (radially inward and downward, or downward). The outward surface 124Ea is a curved surface recessed axially inward and radially outward. The inward surface 124Eb is a conical surface that extends axially outward and radially inward from the axially outer end edge of the outward surface 124Ea. The connection portion of the outward surface 124Ea and the inward surface 124Eb is located axially inward from the axially outer middle position of the recess 124E. As a result, the deepest portion of the recess 124E in the radial direction is formed axially inward of the axial middle position of the recess 124E.

[0129] The grease 460A includes an outer ring contact portion 461A (raceway contact portion) in contact with the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20, and a seal member contact portion 462A in contact with the flat portion 53 of the seal member 50, axially outward and radially inward from the outer ring contact portion 461A. The outer ring contact portion 461A is in contact with the recess 124E of the inner circumferential surface 22b of the protruding portion 22. The outer ring contact portion 461A is in contact with the recess 124E over the entire circumference. The outer ring contact portion 461A is in contact with the outward surface 124Ea of the recess 124E. The outer ring contact portion 461A is in contact with the inward surface 124Eb of the recess 124E. The outer ring contact portion 461A is in contact with the connecting portion of the outward surface 124Ea and the inward surface 124Eb of the recess 124E. Grease 460A is not in contact with ridges 25 of inner circumferential surface 22b. However, grease 460A may be in contact with ridges 25 of inner circumferential surface 22b.

[0130] In this modification, the seal member contact portion 462A is a portion of the grease 460A that contacts the flat portion 53 of the seal member 50. In this modification, the grease 460A is not in contact with the seat portion 51 and the extension portion 52 of the seal member 50. However, the grease 460A may be in contact with at least one of the seat portion 51 and the extension portion 52 of the seal member 50. In this case, it is preferable that the area of ​​the seal member contact portion 462A is larger than the contact area of ​​the grease 460A with the extension portion 52 and the seat portion 51. The grease 460A may be formed such that the cross-sectional area of ​​the cross section along the perpendicular plane of the common axis O gradually increases from the axially outer end toward the axially inner side. The grease 460A extends from the outer ring contact portion 461A toward the seal member contact portion 462A, axially outward and radially inward. The grease 460A extends from the outer ring contact portion 461A along the inward surface 124Eb of the recess 124E.

[0131] In the second modified example shown in FIG. 18, the recess 224E is formed so that the axial width is larger than the radial depth on the longitudinal section of the rolling bearing 1E. The recess 224E includes an outward surface 224Ea facing in a direction inclined axially outward with respect to the radial direction (radially inward and upward, or upward), and an inward surface 224Eb facing in a direction inclined axially inward with respect to the radial direction (radially inward and downward, or downward). The outward surface 224Ea is a flat surface facing axially outward. The inward surface 224Eb is a conical surface extending axially outward and radially inward from the radially outer edge of the outward surface 224Ea. The connection portion of the outward surface 224Ea and the inward surface 224Eb is located axially inward of the axial middle position of the recess 224E. As a result, the deepest portion of the recess 224E in the radial direction is formed axially inward of the axial middle position of the recess 224E.

[0132] Grease 460B includes an outer ring contact portion 461B (raceway contact portion) in contact with inner circumferential surface 22b of protruding portion 22 of outer ring 20, and a seal member contact portion 462B in contact with flat portion 53 of seal member 50, axially outward and radially inward from outer ring contact portion 461B. Outer ring contact portion 461B is in contact with recess 224E of inner circumferential surface 22b of protruding portion 22. Outer ring contact portion 461B is in contact with recess 224E over the entire circumference. Outer ring contact portion 461B is in contact with outward surface 224Ea of recess 224E. Outer ring contact portion 461B is in contact with inward surface 224Eb of recess 224E. Outer ring contact portion 461B is not in contact with the connecting portion of outward surface 224Ea and inward surface 224Eb of recess 224E. Grease 460B is not in contact with edge portion 25 of inner circumferential surface 22b. However, grease 460B may be in contact with edge portion 25 of inner circumferential surface 22b.

[0133] In this modification, the seal member contact portion 462B is a portion of the grease 460B that contacts the flat portion 53 of the seal member 50. In this modification, the grease 460B is not in contact with the seat portion 51 and the extension portion 52 of the seal member 50. However, the grease 460B may be in contact with at least one of the seat portion 51 and the extension portion 52 of the seal member 50. In this case, it is preferable that the area of ​​the seal member contact portion 462B is larger than the contact area of ​​the grease 460B with the extension portion 52 and the seat portion 51. The grease 460B may be formed so that the cross-sectional area of ​​the cross section along the perpendicular plane of the common axis O gradually increases from the axially outer end toward the axially inner side. The grease 460B extends from the outer ring contact portion 461B toward the seal member contact portion 462B, axially outward and radially inward. The grease 460B extends from the outer ring contact portion 461B along the inward surface 224Eb of the recess 224E.

[0134] These modified rolling bearings 1E also provide the same effects as the seventh embodiment.

[0135] [Eighth embodiment] Next, an eighth embodiment will be described with reference to Fig. 19. A rolling bearing 1F of the eighth embodiment differs from the rolling bearing 1 of the first embodiment in the shape of the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20. Note that the configuration other than that described below is the same as that of the first embodiment.

[0136] FIG. 19 is a vertical sectional view of a rolling bearing according to the eighth embodiment. As shown in Fig. 19, the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20 has a recess 24 and a connection surface 26. The recess 24 is provided at an axial distance from the upwardly facing end face 22a of the protruding portion 22. The connection surface 26 is formed between the recess 24 and the upwardly facing end face 22a of the protruding portion 22. The connection surface 26 extends in the axial direction and faces inward in the radial direction. The connection surface 26 is located radially outward from the axial end edge of the outer ring raceway surface 23 so as to be separated from the inner ring 10 in the radial direction.

[0137] In this embodiment, the same effect as in the first embodiment is achieved. In addition, in this embodiment, the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20 has a connection surface 26 formed between the recess 24 and the end surface 22a. The connection surface 26 is located radially outward from the axial end edge of the outer ring raceway surface 23 in the radial direction. According to this configuration, when the tip of the nozzle is inserted from the outside of the rolling bearing 1F to the inside of the outer ring 20 and the inner ring 10 in order to discharge the grease 60 from the nozzle and apply it to a predetermined location, it is possible to make it difficult for the connection surface 26 to come into contact with the nozzle. Therefore, it is easy to bring the nozzle close to the recess 24 when applying the grease 60, so that the productivity of the small-diameter rolling bearing 1F can be improved. In addition, since it is easy to bring the nozzle close to the recess 24, the grease 60 can be applied with high precision, and it is possible to suppress the grease 60 from coming into contact with the rolling element 30 or the like in an amount greater than the desired amount. Therefore, it is possible to reduce the rotational resistance of the rolling bearing 1F.

[0138] [Ninth embodiment] Next, a ninth embodiment will be described with reference to Fig. 20. A rolling bearing 1G of the ninth embodiment differs from the rolling bearing 1 of the first embodiment in the shape of the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20. Note that the configuration other than that described below is the same as that of the first embodiment.

[0139] FIG. 20 is a vertical sectional view of a rolling bearing according to a ninth embodiment. As shown in FIG. 20, the inner peripheral surface 22b of the protruding portion 22 of the outer ring 20 has a recess 224 and an inclined portion 227. The recess 224 is provided without any space in the axial direction from the end face 22a of the protruding portion 22 facing upward, and opens to the inner peripheral surface 22b and the end face 22a facing upward. The recess 224 has an outward surface 224a facing in a direction inclined axially outward with respect to the radial direction (radially inward and upward, or upward), and a cylindrical surface 224c facing radially inward. The outward surface 224a is a concave curved surface. The radially inner edge of the outward surface 224a is located radially outward from the axial edge of the outer ring raceway surface 23 in the radial direction. The cylindrical surface 224c extends in the axial direction and is connected to the axially outer edge of the outward surface 224a. The inclined portion 227 extends from the edge of the recess 224 on the outer ring raceway surface 23 side (the radially inner edge of the outward surface 224a) at an incline in the radial direction and the axial direction toward the outer ring raceway surface 23 side. That is, the inclined portion 227 extends from the ridge portion 25 of the inner circumferential surface 22b inward in the radial direction and inward in the axial direction. In this embodiment, the inclined portion 227 extends linearly from the edge of the recess 224 on the vertical cross section of the rolling bearing 1G. However, it is sufficient that the inclined portion extends at a steeper radial inclination than the recess 224 from the connection portion between the inclined portion and the recess 224 on the vertical cross section of the rolling bearing 1G. The inclined portion 227 is provided at an interval in the axial direction with respect to the outer ring raceway surface 23.

[0140] Grease 560 has an outer ring contact portion 561 in contact with inner circumferential surface 22b of protruding portion 22 of outer ring 20. Outer ring contact portion 561 is in contact with recess 224 of inner circumferential surface 22b of protruding portion 22. Outer ring contact portion 561 is in contact with recess 224 over the entire circumference. Outer ring contact portion 561 is in contact with outward surface 224a and cylindrical surface 224c of recess 224. Outer ring contact portion 561 is also in contact with at least a portion of ridge portion 25 of inner circumferential surface 22b. It is preferable that outer ring contact portion 561 is not in contact with inclined portion 227. Grease 560 may also be in contact with seal member 50.

[0141] In this embodiment, the same effect as in the first embodiment is achieved. In addition, in this embodiment, the inner circumferential surface 22b of the protruding portion 22 of the outer ring 20 has an inclined portion 227 that extends toward the outer ring raceway surface 23 from the end edge of the recess 224 on the outer ring raceway surface 23 side, inclining in the radial and axial directions. According to this configuration, even if the end of the recess 224 on the outer ring raceway surface 23 side extends along the radial direction, the inner circumferential surface 22b gradually inclines from the recess 224 toward the outer ring raceway surface 23, so that it is possible to encourage the base oil exuding from the grease 560 to flow from the recess 224 along the inclined portion 227 toward the outer ring raceway surface 23. Therefore, even if the grease 560 is not arranged close to the outer ring raceway surface 23, it is possible to suppress a shortage of the base oil of the grease 560 to the rolling element 30.

[0142] 21, the grease 560A may be arranged so as not to protrude from the inside of the recess 224 toward the inclined portion 227 (inside) in the radial direction. That is, the grease 560A may be arranged so as not to be located within the formation range of the inclined portion 227 in the radial direction. This configuration can prevent the grease 560A from contacting the rolling element 30. On the other hand, since the application amount of the grease 560A is reduced, it is possible to preferably obtain the effect of preventing the supply of the base oil of the grease 560A to the rolling element 30 from becoming insufficient as described above.

[0143] In the ninth embodiment, the recess 224 is provided without a gap in the axial direction from the upward end face 22a of the protrusion 22, but the present invention is not limited to this configuration. That is, as shown in Fig. 22, the recess 224A may be provided with a gap in the axial direction from the upward end face 22a. In the illustrated example, the recess 224A has an outward surface 224Aa that faces in a direction inclined outward in the axial direction with respect to the radial direction, and an inward surface 224Ab that faces in a direction inclined inward in the axial direction with respect to the radial direction, but the shape of the recess is not particularly limited. EXAMPLES

[0144] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description.

[0145] The viscosity of the grease in this example was measured at 40° C. in accordance with JIS K2283. The consistency of the grease in this example was measured by the method specified in JIS K2220.

[0146] The greases of Examples 1 to 5 and Comparative Examples 1 to 4 were prepared as follows.

[0147] <Example 1> Ester oil and PAO were mixed at a mass ratio (ester oil / PAO) > 1, and the kinematic viscosity was 44 mm 2 Alicyclic urea was synthesized in this base oil as a thickener to obtain a grease with a worked penetration of 228, an unworked penetration of 227, and an unworked penetration of 188 after exposure to high temperatures.

[0148] <Example 2> Using the same base oil and thickener as in Example 1, and adjusting the ratio of thickener to base oil, a grease was obtained with a worked penetration of 261, an unworked penetration of 255, and an unworked penetration of 210 after exposure to high temperatures.

[0149] <Example 3> Ether oil and ester oil were mixed at a mass ratio (ether oil / ester oil) of >1, and the kinematic viscosity was 80 mm 2 Alicyclic urea was synthesized in this base oil to obtain a grease with a worked penetration of 290, an unworked penetration of 274, and an unworked penetration of 282 after exposure to high temperatures.

[0150] <Example 4> PAO alone has a kinetic viscosity of 48 mm 2 Alicyclic urea and aliphatic urea were synthesized in this base oil to obtain a grease with a worked penetration of 199, an unworked penetration of 197, and an unworked penetration of 200 after exposure to high temperatures.

[0151] <Example 5> Ester oil alone has a kinetic viscosity of 100mm 2Alicyclic urea and aliphatic urea were synthesized in this base oil to obtain a grease with a worked penetration of 265, an unworked penetration of 245, and an unworked penetration of 244 after exposure to high temperatures.

[0152] <Comparative Example 1> PAO alone has a kinetic viscosity of 48 mm 2 Alicyclic urea and aliphatic urea were synthesized in this base oil as thickeners to obtain a grease with a worked penetration of 220, an unworked penetration of 170, and an unworked penetration of 158 after exposure to high temperatures.

[0153] <Comparative Example 2> PAO and ester oil were mixed at a mass ratio (PAO / ester oil) > 1, and the kinematic viscosity was 22 mm 2 Alicyclic urea and aliphatic urea were synthesized in this base oil as thickeners to obtain a grease with a worked penetration of 232, an unworked penetration of 178, and an unworked penetration of 149 after exposure to high temperatures.

[0154] <Comparative Example 3> Using the same base oil and thickener as in Example 1 and adjusting the ratio of thickener to base oil, a grease was obtained with a worked penetration of 295, an unworked penetration of 287, and an unworked penetration of 236 after exposure to high temperatures.

[0155] <Comparative Example 4> Mineral oil and PAO were mixed at a mass ratio (mineral oil / PAO) of ≒ 1, and the kinematic viscosity was 52 mm 2 Alicyclic urea and aliphatic urea were synthesized in this base oil as thickeners to obtain a grease with a worked penetration of 248, an unworked penetration of 164, and an unworked penetration of 155 after exposure to high temperatures.

[0156] A durability test of rolling bearings was carried out under the following conditions for each of the greases of Examples 1 to 5 and Comparative Examples 1, 2, and 4. Note that when the grease of Comparative Example 3 was used in the following rolling bearings, the variation in the individual rolling resistance of the rolling bearings was greater than the specified required value, and the rolling resistance varied with the operating time. Therefore, it was determined to be unsuitable as a grease for rolling bearings, and was excluded from the durability test.

[0157] (Roller bearing shape) A rolling bearing with an outer diameter of the outer ring of 8 mm, an inner diameter of the inner ring of 3 mm, and a height (axial thickness) of 4 mm was used.

[0158] (Grease placement) 12 mg of grease was applied in the shape of the grease 60 of the first embodiment.

[0159] (Durability evaluation method) Two rolling bearings using the same grease were installed in one fan motor (rated speed 25,000 rpm). Five fan motors were prepared for each grease of Examples 1 to 5 and Comparative Examples 1 and 2, and were continuously operated in a high-temperature chamber at 85°C to check the operating conditions and the occurrence of abnormal noise every 500 hours. The evaluation results are shown in Table 1.

[0160] [Table 1]

[0161] When the grease of Comparative Example 1 was used, it was confirmed that three of the five fan motors generated abnormal noises after 3000 hours of operation. When the grease of Comparative Example 2 was used, one of the five fan motors stopped after 2000 hours of operation, and two more stopped after 2500 hours of operation. On the other hand, when each of the greases of Examples 1 to 5 was used, the five fan motors operated stably without generating abnormal noises even after 5000 hours of operation. From the above, it is clear that if the unmixed penetration of the grease is greater than 178 and less than 287, the durability of the rolling bearing can be improved while suppressing the occurrence of variations in the rotation resistance of each rolling bearing. Furthermore, it is clear that if the unmixed penetration of the grease satisfies the above conditions and the difference between the mixed penetration and the unmixed penetration is less than 50, the durability of the rolling bearing can be reliably improved. Furthermore, it is clear that if the unmixed penetration of the grease satisfies the above conditions and the ratio of the difference between the worked penetration and the unmixed penetration to the worked penetration is less than 22.7%, the durability of the rolling bearing can be reliably improved.

[0162] The present invention is not limited to the above-described embodiment explained with reference to the drawings, and various modifications are possible within the technical scope of the present invention. For example, in the above embodiment, the inner ring 10 is provided as a rotating ring, and the outer ring 20 is provided as a fixed ring. And, the grease 60, 160, 160A, 260, 260A, 360, 360A, 360B, 460, 460A, 460B, 560, 560A is in contact with the outer ring 20 which is a fixed ring. However, the raceway ring with which the grease is in contact does not have to be a fixed ring. That is, the inner ring may be provided as a fixed ring, the outer ring may be provided as a rotating ring, and the grease may be in contact with the inner ring which is a fixed ring. Also, the inner ring may be provided as a fixed ring, the outer ring may be provided as a rotating ring, and the grease may be in contact with the outer ring which is a rotating ring.

[0163] In addition, in each of the above-described embodiments, the grease 60, 160, 160A, 260, 260A, 360, 360A, 360B, 460, 460A, 460B, 560, 560A is in contact with the entire circumference of the recess, but this is not limited to the configuration. The grease may be in contact with only a portion of the recess in the circumferential direction.

[0164] In addition, the shape of the seal member and the mode of the contact portion between the seal member and the grease are not limited to the above embodiment. For example, the seal member may not have an extension portion, and the flat portion may be formed so as to extend radially inward from the pedestal portion. For example, the grease may be in contact with both the flat portion and the extension portion of the seal member, or may be in contact with the extension portion without contacting the flat portion. Since the grease has the properties of the above embodiment, as long as the grease is in contact with at least one of the flat portion and the extension portion, the shape of the portion of the grease 60 that is not in contact with the rolling element 30 and the cage 40 is easily maintained in its initial shape. Therefore, it is possible to suppress the shape of the grease 60 being different for each rolling bearing 1 and causing variations in rotational resistance.

[0165] In addition, in the above embodiment, the grease 60, 160, 160A, 260, 260A, 360, 360A, 360B, 460, 460A, 460B, 560, 560A is not in contact with the inner ring 10 and the cage 40, but the present invention is not limited to this configuration. As described above, in the above embodiment, it is possible to prevent the grease from spreading significantly toward the inner ring 10 and the rolling elements 30 when the seal member 50 is attached. Therefore, even if the grease contacts at least one of the inner ring 10 and the cage 40, the contact area can be made sufficiently small compared to the conventional structure, and therefore the effect of reducing the rotational resistance can be obtained.

[0166] In addition, in the above embodiment, the grease is arranged on the opposite side of the annular portion 41 of the retainer 40 across the rolling body 30 in the axial direction, but the grease may also be arranged on the annular portion 41 side of the retainer 40 relative to the rolling body 30 in the axial direction.

[0167] Further, the rolling bearing may be provided with grease other than grease 60, 160, 160A, 260, 260A, 360, 360A, 360B, 460, 460A, 460B, 560, 560A. In the above embodiment, the grease is provided on the opposite side of the rolling element 30 from the annular portion 41 of the cage 40 in the axial direction, but the grease may also be provided on the annular portion 41 side of the cage 40 with respect to the rolling element 30 in the axial direction. For example, the rolling bearing may further include grease applied to a grease pocket, a lower end surface, etc. of the cage.

[0168] In the above embodiment, a fan motor is used as an example of a rotating device, but the rotating device is not limited to this. For example, the present invention may be applied to a dental handpiece, a spindle motor of a hard disk drive, or the like as a rotating device.

[0169] In addition, in the above-mentioned embodiment, all the greases are thickened only by urea synthesized in the base oil, and no gelling agent is used.

[0170] In addition, within the scope of the spirit of the present invention, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate. [Explanation of symbols]

[0171] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G...Bearing 2...Rotating device 10...Inner ring (other raceway ring) 20...Outer ring (one raceway ring) 22...Protrusion 22a...End face 22b...Inner peripheral surface (circumferential surface) 23...Outer ring raceway surface (raceway surface) 24, 24A, 24B, 24C, 24C, 24D, 24E, 124, 124E, 224, 224A, 224E...Recess 25, 25A, 25B, 25C...Ridge 30...Rolling element 50...Sealing member 51...Pedestal portion 52...Extending portion 53...Flat portion 60,160,160A,260,260A,360,360A,360B,460,460A,460B,560,560A...Grease 61,161,261,361,461,461A,461B,561...Outer ring contact part (raceway contact part) 62,162,262,462,462A,462B...Seal member contact part 227...Inclined part

Claims

1. An inner ring and an outer ring arranged coaxially with each other; A rolling element disposed between the inner ring and the outer ring; a seal member attached to the inner ring or the outer ring and covering a gap between the inner ring and the outer ring from an outside in the axial direction; grease disposed between the rolling element and the seal member; Equipped with one of the inner ring and the outer ring has a circumferential surface facing the other of the inner ring and the outer ring; The peripheral surface has a raceway surface that supports the rolling elements so that they can roll; a recess provided at a location extending in the axial direction from an end edge of the raceway surface, the recess being recessed in a radial direction; is formed, The grease is in contact with the recess, The unmixed penetration of the grease is greater than 178 and less than 287. Rolling bearing.

2. The grease is in contact with a portion of the recess that faces a direction inclined outward in the axial direction with respect to a radial direction.

2. The rolling bearing according to claim 1.

3. The recess has a portion that faces a direction inclined inwardly in the axial direction with respect to a radial direction.

3. The rolling bearing according to claim 1 or 2.

4. The grease is in contact with the seal member.

3. The rolling bearing according to claim 1 or 2.

5. The grease is in contact with a ridge portion formed on an edge of the recess on the raceway surface side.

3. The rolling bearing according to claim 1 or 2.

6. the one raceway has a protruding portion that protrudes toward the other raceway and has the circumferential surface formed thereon, the protruding portion has an end surface facing outward in the axial direction and connected to the circumferential surface at a circumferential edge on the other raceway ring side, the peripheral surface has a connection surface formed between the recess and the end surface, the connection surface is farther from the other raceway ring in the radial direction than the axial end edge of the raceway surface; 3. The rolling bearing according to claim 1 or 2.

7. the peripheral surface has an inclined portion extending from an edge of the recess on the raceway surface side toward the raceway surface while being inclined with respect to the radial direction and the axial direction, 3. The rolling bearing according to claim 1 or 2.

8. The grease is arranged so as not to protrude from the inside of the recess toward the inclined portion in the radial direction.

8. A rolling bearing according to claim 7.

9. The difference between the worked and unworked penetration of the grease is less than 50; 2. The rolling bearing according to claim 1.

10. The ratio of the difference between the worked penetration and the unworked penetration to the worked penetration of the grease is less than 22.7%; 2. The rolling bearing according to claim 1.

11. The unmixed penetration of the grease after standing for 18 hours at 85°C is greater than 158. A rolling bearing according to claim 1, claim 9 or claim 10.

12. A rotating body that is rotatably arranged; A support that rotatably supports the rotating body; The rolling bearing according to claim 1 interposed between the rotating body and the support body; A rotating device comprising:

13. An inner ring and an outer ring arranged coaxially with each other; A rolling element disposed between the inner ring and the outer ring; a seal member attached to the inner ring or the outer ring and covering a gap between the inner ring and the outer ring from an outside in the axial direction; grease disposed between the rolling element and the seal member; Equipped with one of the inner ring and the outer ring has a circumferential surface facing the other of the inner ring and the outer ring; The peripheral surface has a raceway surface that supports the rolling elements so that they can roll; a recess provided at a location extending in the axial direction from an axial end edge of the raceway surface and recessed in a radial direction; A method for manufacturing a rolling bearing having a a coating step of applying the grease to the recess by contacting the grease with the recess, The unmixed penetration of the grease is greater than 178 and less than 287. A method for manufacturing rolling bearings.

14. The sealing member is an annular seat portion that contacts the one of the raceways from an outside in the axial direction; an extension portion extending outward in the axial direction from a peripheral edge of the seat portion on a bearing ring side of the other of the inner ring and the outer ring; a flat surface portion extending radially from an axially outer end edge of the extension portion toward the other raceway; having In the application step, the grease is applied so as to protrude from a contact portion with the one raceway ring toward an outer side in the axial direction and toward the other raceway ring, a contacting step of bringing the seal member close to the one race from the outside in the axial direction to bring the flat portion into contact with an outer edge of the grease in the axial direction; an installation step of, after the contact step, bringing the seal member close to the one of the raceways to bring the base portion into contact with the one of the raceways from the outside in the axial direction and pressing the grease inward in the axial direction with the flat portion; The method for manufacturing a rolling bearing according to claim 13, further comprising:

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