Rolling bearing, rotary device, and manufacturing method of rolling bearing

Abstract

The present application relates to a rolling bearing, a rotary device, and a manufacturing method of a rolling bearing, and provides a rolling bearing capable of achieving low torque. A rolling bearing (1) includes an inner ring (10) and an outer ring (20) arranged coaxially, a rolling element (30) arranged between the inner ring (10) and the outer ring (20), and a grease filler (60) arranged between the inner ring (10) and the outer ring (20). The grease filler (60) has a single arc-shaped portion (61) extending in an arc shape in a circumferential direction around a common axis (O) of the inner ring (10) and the outer ring (20) at a prescribed position in an axial direction of the common axis (O) and in a radial direction centered on the common axis (O), and is in contact with one of the inner ring (10) and the outer ring (20). A first end portion (61a) of the arc-shaped portion (61) is arranged apart in the circumferential direction from a second end portion (61b) of the arc-shaped portion (61).

Description

Technical Field

[0001] This invention relates to rolling bearings, rotating equipment, and methods for manufacturing rolling bearings. Background Technology

[0002] Traditionally, rolling bearings have been those that retain grease between a pair of raceways (inner and outer rings). In these bearings, the resistance of the grease can sometimes be a major cause of increased torque. Furthermore, in rolling bearings, low torque is desired to reduce the power consumption of the rotating equipment they are mounted on. This requirement for low torque is particularly strong in small rolling bearings used in various electric motors, such as fan motors.

[0003] Therefore, in order to reduce the torque of the rolling bearing, grease is applied to the sealing member disposed at the axial end of the fixed ring (in most cases the outer ring) of the rolling bearing. This reduces the amount of grease that contacts the rolling elements (balls) and the retainer holding the rolling elements (for example, see Patent Document 1). In the rolling bearing described in Patent Document 1, grease is attached to the inner circumferential surface of the outer ring that avoids contact with the track surface of the rolling elements, and is filled in an annular shape on the inner circumferential surface of the outer ring in a manner that does not contact the outer circumferential surface of the inner ring.

[0004] Existing technical documents Patent documents Patent document 1: Japanese Patent Application Publication No. 2013-204679. Summary of the Invention

[0005] The problem that the invention aims to solve Furthermore, one method for applying grease in a circular pattern to the raceway ring involves dispensing grease from a nozzle while simultaneously rotating the nozzle relative to the raceway ring. However, if the grease is applied in a circular pattern throughout the ring, overlapping portions form between the start and end points. These overlapping portions of the grease sometimes slowly collapse under their own weight, exceeding necessary contact with the rolling elements and retainer, potentially causing the torque of the rolling bearing to become greater than desired.

[0006] Therefore, the present invention provides a rolling bearing, a rotating device, and a method for manufacturing a rolling bearing that can achieve low torque.

[0007] Solution for solving the problem The rolling bearing of the present invention is characterized by comprising: an inner ring and an outer ring arranged coaxially with each other; a rolling element disposed between the inner ring and the outer ring; and a grease disposed between the inner ring and the outer ring, the grease having a single arcuate portion that extends in an arcuate shape in the circumferential direction about the common axis of the inner ring and the outer ring at a predetermined position in the axial direction and in the radial direction centered on the common axis, and contacts one of the inner ring and the outer ring, the first end of the arcuate portion being spaced apart from the second end of the arcuate portion in the circumferential direction.

[0008] According to the present invention, since a gap is provided between the first end and the second end of the arc-shaped portion, overlapping portions in the arc-shaped portion can be suppressed. This makes it difficult for the grease to collapse due to its own weight. Therefore, it is possible to prevent the grease from making excessive contact with the rolling elements and the retainer. Thus, low torque in the rolling bearing can be achieved. Furthermore, since the arc-shaped portion is singular at predetermined positions in the axial and radial directions, the only portion in the circumferential direction where the arc-shaped portion is not provided is the gap between the first and second ends. Therefore, compared to a configuration where grease is intermittently arranged along the circumferential direction, the portion where grease is not arranged in the circumferential direction is reduced, allowing for finer grease arrangement when filling the desired amount. Therefore, it is possible to prevent the grease from making excessive contact with the rolling elements and the retainer. Thus, low torque in the rolling bearing can be achieved.

[0009] In the aforementioned rolling bearing, one of the aforementioned inner ring and the aforementioned outer ring can also be configured as a fixed ring.

[0010] According to the present invention, since the grease is in contact with the retaining ring, centrifugal force acting on the grease can be suppressed during the rotation of the rolling bearing, and the collapse of the grease from its freshly applied shape can be prevented. Therefore, low torque in the rolling bearing can be achieved.

[0011] In the aforementioned rolling bearing, one of the aforementioned inner ring and the aforementioned outer ring can also be the aforementioned outer ring.

[0012] According to the present invention, even when the grease rotates and centrifugal force acts on the grease during the rotation of the rolling bearing, the radially outward displacement of the grease is restricted by the outer ring, thus maintaining the grease in its freshly applied shape. Therefore, low torque in the rolling bearing can be achieved.

[0013] In the aforementioned rolling bearing, the grease may also have a drawing portion extending from one of the aforementioned first end and the aforementioned second end of the aforementioned arc-shaped portion, the drawing portion crossing the gap between the aforementioned first end and the aforementioned second end of the aforementioned arc-shaped portion, and connected to the aforementioned first end and the aforementioned second end of the aforementioned arc-shaped portion.

[0014] When forming the arc-shaped portion of the grease, and when the nozzle that has finished dispensing the grease separates from the rolling bearing, sometimes a stringy portion extends from the arc-shaped portion due to the viscosity of the grease. According to the present invention, the stringy portion is elongated from one of the first and second ends of the arc-shaped portion, so that the stringy portion crosses the gap between the first and second ends of the arc-shaped portion and connects to the other of the first and second ends of the arc-shaped portion, thereby preventing the stringy portion from drooping and falling from the gap between the first and second ends of the arc-shaped portion. This prevents the grease from being positioned closer to the rolling elements and retainer than desired. Therefore, it prevents the grease from making unnecessary contact with the rolling elements and retainer. Consequently, low torque in the rolling bearing can be achieved.

[0015] In the aforementioned rolling bearing, a sealing member may also be provided that covers the space between the inner ring and the outer ring from the outer side of the axial direction. The grease has a single other arc-shaped portion that extends in an arc shape in the circumferential direction at a position different from the arc-shaped portion in the axial and radial directions. It is connected to the arc-shaped portion and contacts the sealing member. The first end of the other arc-shaped portion is spaced apart from the second end of the other arc-shaped portion in the circumferential direction.

[0016] According to the present invention, when filling the desired amount of grease, compared with the case where only an arc-shaped portion is provided, the volume of the arc-shaped portion can be reduced corresponding to the provision of both the arc-shaped portion and the other arc-shaped portion. Therefore, by forming the arc-shaped portion earlier than the other arc-shaped portion during grease application, it is possible to prevent the arc-shaped portion from collapsing due to its own weight. In addition, by providing the other arc-shaped portion, the other arc-shaped portion is supported by the sealing member, and the arc-shaped portion is supported not only by one of the inner and outer rings, but also by the sealing member via the other arc-shaped portion. Therefore, the grease as a whole becomes less likely to collapse from its freshly applied shape due to its own weight. Furthermore, the other arc-shaped portion, like the arc-shaped portion, is formed with a gap between the first end and the second end, thus preventing the formation of overlapping portions in the other arc-shaped portion. As a result, the grease becomes less likely to collapse due to its own weight. Based on the above, it is possible to prevent the grease from making excessive contact with the rolling elements and the retainer. Therefore, it is possible to achieve low torque in the rolling bearing.

[0017] In the aforementioned rolling bearing, the other arc-shaped portion may also span the gap between the first end and the second end of the aforementioned arc-shaped portion.

[0018] According to the present invention, the grease is disposed throughout the circumferential area, thus enabling the grease to be uniformly disposed throughout the circumferential area of ​​the rolling bearing. Furthermore, the first and second ends of the arc-shaped portion are connected to and supported by another arc-shaped portion, thereby suppressing grease collapse due to external interference.

[0019] In the aforementioned rolling bearing, the aforementioned sealing component may also be assembled into one of the aforementioned inner ring and the aforementioned outer ring.

[0020] According to the present invention, one of the inner and outer rings, as well as the sealing member, is configured to not rotate relative to each other, thereby suppressing the agitation of the grease in contact with both sides. Therefore, the grease can be maintained in its freshly applied shape. Consequently, low torque in the rolling bearing can be achieved.

[0021] In the aforementioned rolling bearing, the other arc-shaped portion may also be arranged radially on the opposite side of one of the aforementioned inner ring and outer ring, relative to the aforementioned arc-shaped portion.

[0022] According to the present invention, compared with a configuration in which the arcuate portion and another arcuate portion are arranged side by side in the axial direction, a space for arranging the arcuate portion can be provided on one side of the inner and outer rings in the radial direction relative to the other arcuate portion, thus positioning the arcuate portion further outward in the axial direction. This prevents grease from making excessive contact with the rolling elements and the retainer. Consequently, low torque in the rolling bearing can be achieved.

[0023] In the aforementioned rolling bearing, another grease may also be provided, which is disposed on the opposite side of the aforementioned grease in the aforementioned axial direction relative to the aforementioned rolling element.

[0024] According to the present invention, the total amount of grease disposed in the bearing can be increased by using another type of grease. This, in turn, enables the provision of bearings with extended service life.

[0025] The rotating device of the present invention is characterized by comprising: a rotating body rotatably configured; a support body rotatably supporting the aforementioned rotating body; and a rolling bearing, as described in any one of technical solutions 1 to 6, located between the aforementioned rotating body and the aforementioned support body.

[0026] According to the present invention, a rolling bearing with reduced torque is provided, thereby reducing the rotational resistance of the rotating body relative to the support body and achieving energy saving of the rotating equipment.

[0027] The method for manufacturing a rolling bearing according to the present invention is the same as the method for manufacturing a rolling bearing described above, characterized by comprising: a first coating step in which grease is dispensed from a first nozzle at a first coating position to form the aforementioned arc-shaped portion; and a second coating step in which grease is dispensed from a second nozzle at a second coating position different from the aforementioned first nozzle to form the aforementioned other arc-shaped portion.

[0028] According to the present invention, the cycle time at each coating position can be shortened. Therefore, the manufacturing efficiency of bearings can be improved. In addition, in the manufacturing method of rotating the bearing while applying grease in a ring shape, a mechanism for driving the nozzle radially relative to the bearing is not required, thus simplifying the structure of the grease coating apparatus.

[0029] Invention Effects According to the present invention, a rolling bearing, a rotating device, and a method for manufacturing a rolling bearing that can achieve low torque can be provided. Attached Figure Description

[0030] Figure 1 This is a top view of the rolling bearing according to the first embodiment.

[0031] Figure 2 yes Figure 1 A cross-sectional view along line II-II.

[0032] Figure 3 This is a top view illustrating the application method of grease.

[0033] Figure 4 This is a top view illustrating the application method of grease.

[0034] Figure 5 This is a top view of the rolling bearing according to the second embodiment.

[0035] Figure 6 This is a top view of the rolling bearing according to the third embodiment.

[0036] Figure 7 yes Figure 6 A cross-sectional view along line VII-VII.

[0037] Figure 8 This is a cross-sectional view of the rolling bearing according to the fourth embodiment.

[0038] Figure 9 This is a cross-sectional view of the rolling bearing according to the fifth embodiment. Detailed Implementation

[0039] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. Furthermore, in the following description, configurations having the same or similar functions will be given the same reference numerals. Also, repeated descriptions of these configurations will sometimes be omitted.

[0040] [First Implementation Method] Reference from Figures 1 to 8 The first embodiment of the present invention will be described below. Figure 1 This is a top view of the rolling bearing according to the first embodiment. Figure 2 yes Figure 1 A cross-sectional view along line II-II. Furthermore, in Figure 1 In order to facilitate observation of the internal structure of the rolling bearing 1, the illustrations of portions of the sealing member 50 and the filling grease 60, which will be described later, are omitted. Additionally, in Figure 2 In the image, the components for assembling the rolling bearing 1 are shown with imaginary lines.

[0041] like Figure 1 and Figure 2 As shown, the rolling bearing 1 is a ball bearing comprising an inner ring 10 and an outer ring 20 (which are raceways), a plurality of rolling elements 30, a retainer 40, a pair of sealing members 50, and a grease 60 filling. The rolling bearing 1 is installed in a rotating device 2 such as a fan motor. The rotating device 2 includes a shaft 3 (rotating body) rotatably formed around a common axis O, and a frame 4 (support body) fixedly set and rotatably supporting the shaft 3. The rolling bearing 1 is located between the shaft 3 and the frame 4. Furthermore, the rolling bearing will sometimes be simply referred to as a bearing in the following description. Additionally, in this embodiment, the grease in the state before filling the bearing 1 is simply referred to as grease, and the grease in the state after being filled into the bearing 1 by applying grease is referred to as grease 60.

[0042] The inner ring 10 and the outer ring 20 are coaxially arranged so that their respective central axes are aligned with a common axis O. In this embodiment, the direction of extension of the common axis O is referred to as the axial direction, the direction that is orthogonal to the common axis O and extends radially from the common axis O is referred to as the radial direction, and the direction of rotation around the common axis O is referred to as the circumferential direction.

[0043] The inner ring 10 is configured as a rotating ring. The inner ring 10 is inserted into and fixed to the shaft 3. The outer ring 20 is configured as a fixed ring. The outer ring 20 is embedded in a recess (or through hole) of the frame 4 and fixed to the frame 4. With an annular space between the outer ring 20 and the inner ring 10, the outer ring 20 surrounds the inner ring 10 from the radially outer side. A plurality of rolling elements 30 are disposed between the inner ring 10 and the outer ring 20 and are rotatably held by a retainer 40. The retainer 40 rotatably holds each rolling element 30 with the plurality of rolling elements 30 evenly arranged in the circumferential direction. A sealing member 50 covers the annular space between the inner ring 10 and the outer ring 20 from the axially outer side.

[0044] The outer ring 20 is formed into a circular shape from a metal material such as stainless steel or bearing steel. However, the outer ring 20 is not limited to metal and can also be formed from other materials. The outer ring 20 has: an outer ring body 21, the width of which along the axial direction is equal to the width of the inner ring 10 along the axial direction; and a protrusion 22, which protrudes radially inward from the outer ring body 21. The protrusion 22 is formed in the axially central portion of the outer ring body 21. The width of the protrusion 22 along the axial direction is shorter than the width of the outer ring body 21 along the axial direction, but larger than the outer diameter of the rolling element 30.

[0045] On the inner circumferential surface of the protrusion 22, an outer ring rolling surface 23 is formed that is recessed outward toward the radial direction. The outer ring rolling surface 23 is formed as a hemispherical shape in cross-section along the outer surface of the rolling element 30, and is formed as an annular shape extending circumferentially over the entire circumference of the inner circumferential surface of the protrusion 22. The outer ring rolling surface 23 is formed in the portion of the inner circumferential surface of the protrusion 22 located at the axial center. The portion of the inner circumferential surface of the protrusion 22 other than the outer ring rolling surface 23 extends axially with a fixed inner diameter. The protrusion 22 has a pair of end faces 22a facing axially. Each end face 22a extends parallel to both the radial and circumferential directions.

[0046] The outer ring body 21 has a pair of inner circumferential surfaces 21a extending from the outer periphery 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 axially inner is located radially outer than the portion located axially outer.

[0047] The inner ring 10 is formed into a circular shape from a metal material such as stainless steel or bearing steel. However, the inner ring 10 is not limited to metal and can also be formed from other materials. An inner ring rolling surface 11, radially recessed inward, is formed on the outer circumferential surface of the inner ring 10. The inner ring rolling surface 11 is formed as a hemispherical shape in cross-section along the outer surface of the rolling element 30, and is formed as a ring extending circumferentially over the entire outer circumference. The inner ring rolling surface 11 is formed in the axially central portion of the outer circumferential surface of the inner ring 10 and is arranged radially opposite to the outer ring rolling surface 23. The portion of the inner circumferential surface of the inner ring 10, excluding the inner ring rolling surface 11, extends axially with a fixed outer diameter.

[0048] Multiple rolling elements 30 are formed into spherical shapes from metal materials such as stainless steel and bearing steel. The multiple rolling elements 30 are disposed between the outer ring rolling surface 23 and the inner ring rolling surface 11, and are rotatably supported by the outer ring rolling surface 23 and the inner ring rolling surface 11.

[0049] The retainer 40 is integrally formed into a ring shape from synthetic resin or metal. The retainer 40 is arranged centered on a common axis O. The retainer 40 includes a main body 41 formed into a ring shape and disposed on the opposite side of the axial direction relative to the plurality of rolling elements 30, and a plurality of pairs of claw portions 42 erected from the main body 41 toward one side of the axial direction. The pair of claw portions 42 rotatably retain one rolling element 30. The pair of claw portions 42 are erected in an arc shape from the main body 41 toward the front end, approaching each other at a relatively close distance. The retainer 40 is arranged with a gap relative to the inner ring 10 and the outer ring 20 so as not to interfere with them. In this embodiment, the retainer 40 as a whole is located further axially inside than the pair of end faces 22a of the protrusions 22 of the outer ring 20.

[0050] The sealing member 50 is formed as an annular plate. The sealing member 50 is arranged centered on a common axis O. The sealing member 50 is fitted onto the outer ring 20. One sealing member 50 is arranged on each side axially relative to the plurality of rolling elements 30. The sealing member 50 includes: a base 51 that overlaps axially outward at the end face 22a of the protrusion 22 of the outer ring 20; a stepped portion 52 that extends axially outward from the inner periphery of the base 51; a cover portion 53 that extends radially inward from the axially outward end edge of the stepped portion 52; and a locking portion 54 that extends radially outward and axially outward from the outer periphery of the base 51. The sealing member 50 extends radially at least across the center of the rolling element 30 when viewed from above. In this embodiment, the cover portion 53 overlaps with the center of the rolling element 30 when viewed from above. However, it is also possible that the stepped portion 52 extends axially outward and radially inward from the inner periphery of the base 51, overlapping with the center of the rolling element 30 when viewed from above. The inner periphery of the cover portion 53 is configured with a clearance from the outer periphery of the inner ring 10. The outer periphery of the locking portion 54 engages axially from the inner side with the inner periphery 21a of the outer ring body 21. Thus, the sealing member 50 is fixed to the outer ring 20.

[0051] A filler grease 60 is disposed between the rolling element 30 and the sealing member 50. The filler grease 60 is disposed only on one side of the annular space between the inner ring 10 and the outer ring 20, relative to the axial direction of the rolling element 30. In this embodiment, the filler grease 60 is disposed on one side relative to the axial direction of the rolling element 30. That is, the filler grease 60 clamps the rolling element 30 in the axial direction and is disposed on the side opposite to the main body 41 of the retainer 40. The filler grease 60 is arranged in a ring shape in plan view and is arranged coaxially with the common axis O. The filler grease 60 contacts the outer ring 20, which is provided as a fixed ring, and separates from the inner ring 10, which is provided as a rotating ring. Furthermore, the filler grease 60 contacts the inner surface of the cover portion 53 of the sealing member 50 and is supported by the sealing member 50.

[0052] The filling grease 60 includes a single arc-shaped portion 61 extending in a circumferential arc at predetermined positions in the axial and radial directions. That is, the arc-shaped portion 61 extends without interruption, without changing its axial and radial positions. The arc-shaped portion 61 extends 180° to less than 360° from a first end 61a, which is one circumferential end, to a second end 61b, which is the other circumferential end. Thus, the first end 61a of the arc-shaped portion 61 is spaced apart from the second end 61b in the circumferential direction. It is desirable that the circumferential distance between the first end 61a and the second end 61b of the arc-shaped portion 61 is sufficiently small within the range where the first end 61a does not contact the second end 61b. For example, the circumferential distance between the first end 61a and the second end 61b of the arc-shaped portion 61 is set to be smaller than the width of the arc-shaped portion 61 when viewed from above. Additionally, for example, the circumferential distance between the first end 61a and the second end 61b of the arc-shaped portion 61 is set to be smaller than the axial thickness of the arc-shaped portion 61. The arc-shaped portion 61 contacts the outer ring 20. Specifically, the arc-shaped portion 61 contacts a portion of the inner circumferential surface of the protrusion 22 of the outer ring 20 that is axially outer than the rolling surface 23 of the outer ring. In the illustrated example, the arc-shaped portion 61 is separated from the sealing member 50. However, the arc-shaped portion 61 may also contact the sealing member 50.

[0053] Next, as a method for manufacturing the bearing 1 in this embodiment, the method for applying grease will be described. Figure 3 and Figure 4 This is a top view illustrating the application method of grease. For example... Figure 3 As shown, grease is applied with the sealing component 50 not installed on the outer ring 20. That is, the annular space between the inner ring 10 and the outer ring 20 is open in the axial direction, and grease is applied with the rolling element 30 and the retainer 40 exposed.

[0054] like Figure 4 As shown, a nozzle (not shown) is rotated relative to the outer ring 20 about a common axis O, while grease G is ejected from the nozzle. At this time, the position of the nozzle is adjusted so that the ejected grease G contacts the axial end of the inner circumferential surface of the protrusion 22 of the outer ring 20. Because the nozzle is rotated relative to the outer ring 20 while ejecting grease G, the grease extends into an arc shape. The grease adhering to the outer ring 20 extends less than 360° from the starting end 71 corresponding to the ejection start point to the terminal end 72 corresponding to the ejection end point. Thus, an arc-shaped portion 61 with a gap between the first end 61a and the second end 61b is formed.

[0055] Based on the above, the grease application is complete. Subsequently, the sealing component 50 is inserted from the outer side of the axial direction into the annular space between the inner ring 10 and the outer ring 20, and the sealing component 50 is assembled onto the outer ring 20.

[0056] As explained above, the bearing 1 of this embodiment includes a grease 60, which has a single arc-shaped portion 61 extending circumferentially into an arc shape at predetermined positions in the axial and radial directions and contacting the outer ring 20. The first end portion 61a of the arc-shaped portion 61 is spaced apart circumferentially from the second end portion 61b of the arc-shaped portion 61. With this configuration, since a gap is provided between the first end portion 61a and the second end portion 61b of the arc-shaped portion 61, overlapping portions of the arc-shaped portion 61 can be suppressed. Therefore, the grease 60 becomes less prone to collapse due to its own weight. Thus, it is possible to prevent the grease 60 from making necessary contact with the rolling element 30 and the retainer 40. Therefore, low torque in the bearing 1 can be achieved.

[0057] Furthermore, since the arcuate portion 61 is singular at the specified positions in both the axial and radial directions, the only portion in the circumferential direction where the arcuate portion 61 is not provided is the interval between the first end 61a and the second end 61b. Therefore, compared to a configuration where grease is intermittently arranged along the circumferential direction, the number of portions where grease is not provided in the circumferential direction is reduced, allowing for a finer arrangement of the filling grease 60 when the desired amount of grease is filled. Consequently, it is possible to prevent the filling grease 60 from making excessive contact with the rolling element 30 and the retainer 40. Therefore, a lower torque in the bearing 1 can be achieved.

[0058] Furthermore, the outer ring 20 of the track ring that the filler grease 60 contacts is provided as a retaining ring. With this configuration, the filler grease 60 contacts the retaining ring, thus suppressing centrifugal force acting on the filler grease 60 during bearing 1 rotation and preventing the filler grease 60 from collapsing from its initial shape after application. Therefore, low torque in the bearing 1 can be achieved.

[0059] [Second Implementation] Reference Figure 5 The second embodiment of the present invention will now be described. Furthermore, the configuration, except as described below, is the same as that of the first embodiment.

[0060] Figure 5 This is a top view of the rolling bearing according to the second embodiment. Furthermore, in Figure 5 In order to facilitate observation of the internal structure of bearing 1A, the illustration of sealing component 50 is omitted. Figure 5As shown, the filling grease 60A of the second embodiment has a stringing portion 63 in addition to the arc-shaped portion 61. The stringing portion 63 spans the gap between the first end 61a and the second end 61b of the arc-shaped portion 61. The stringing portion 63 is connected to the first end 61a and the second end 61b of the arc-shaped portion 61. The stringing portion 63 extends axially outward relative to the circumferential direction from the second end 61b of the arc-shaped portion 61, which corresponds to the end point of grease ejection when the arc-shaped portion 61 is formed, until it overlaps with the first end 61a in plan view. Thus, the stringing portion 63 is distinguished from the extending arc-shaped portion 61 at predetermined positions in the axial and radial directions because it is inclined circumferentially and extends simultaneously. The cross-sectional area of ​​the stringing portion 63 (the section orthogonal to the circumferential direction) is smaller than the cross-sectional area of ​​the arc-shaped portion 61. The cross-sectional area of ​​the stringing portion 63 gradually decreases from the connection portion with the second end 61b of the arc-shaped portion 61 while extending simultaneously. The drawing portion 63 contacts the inner circumferential surface of the protrusion 22 of the outer ring 20. However, the drawing portion 63 can also be separated from the outer ring 20.

[0061] Thus, when the arc-shaped portion 61 of the filled grease 60A is formed, when the nozzle that has finished dispensing the grease separates from the bearing 1A, a wire-drawing portion 63, due to the high viscosity of the grease and having a smaller cross-sectional area than the arc-shaped portion 61, extends from the second end 61b of the arc-shaped portion 61. According to this embodiment, by elongating the wire-drawing portion 63 from the second end 61b of the arc-shaped portion 61, and allowing the wire-drawing portion 63 to cross the gap between the first end 61a and the second end 61b of the arc-shaped portion 61 and connect to the first end 61a of the arc-shaped portion 61, it is possible to prevent the wire-drawing portion 63 from drooping and falling from the gap between the first end 61a and the second end 61b of the arc-shaped portion 61. This prevents the filled grease 60A from being positioned closer to the rolling element 30 and the retainer 40 than desired. Therefore, it is possible to prevent the filled grease 60A from making excessive contact with the rolling element 30 and the retainer 40. Consequently, a low torque on the bearing 1A can be achieved.

[0062] [Third Implementation Method] Reference Figure 6 and Figure 7 The third embodiment of the present invention will now be described. Furthermore, the configuration, except as described below, is the same as that of the first embodiment.

[0063] Figure 6 This is a top view of the rolling bearing according to the third embodiment. Figure 7 yes Figure 6 A cross-sectional view along line VII-VII. Furthermore, in Figure 6 In order to facilitate observation of the internal structure of bearing 1B, the illustration of sealing component 50 is omitted. Figure 6 and Figure 7As shown, the filling grease 160 of the third embodiment includes a single first arcuate portion 161 (arc portion) extending in an arcuate shape in the circumferential direction at predetermined positions in the axial and radial directions, and a single second arcuate portion 162 (another arcuate portion) extending in an arcuate shape in the circumferential direction at positions different from the first arcuate portion 161 in the axial and radial directions. The first arcuate portion 161 and the second arcuate portion 162 are formed by applying grease separately in two separate applications. The first arcuate portion 161 is formed in the same manner as the arcuate portion 61, except that its cross-sectional area is smaller than that of the arcuate portion 61 in the first embodiment. That is, the first end portion 161a of the first arcuate portion 161 is spaced apart from the second end portion 161b in the circumferential direction.

[0064] The second arcuate portion 162 extends without interruption, without changing its axial and radial positions. The second arcuate portion 162 extends 180° to less than 360° from the first end portion 162a, which is one circumferential end portion, to the second end portion 162b, which is the other circumferential end portion. Thus, the first end portion 162a of the second arcuate portion 162 is spaced apart from the second end portion 162b in the circumferential direction. It is desirable that the circumferential distance between the first end portion 162a and the second end portion 162b of the second arcuate portion 162 is set to be smaller than the width of the second arcuate portion 162 when viewed from above. It is also desirable that the circumferential distance between the first end portion 162a and the second end portion 162b of the second arcuate portion 162 is set to be smaller than the axial thickness of the second arcuate portion 162. The distance between the first end portion 162a and the second end portion 162b of the second arcuate portion 162 is positioned circumferentially offset from the distance between the first end portion 161a and the second end portion 161b of the first arcuate portion 161. Thus, the second arc-shaped portion 162 spans the gap between the first end portion 161a and the second end portion 161b of the first arc-shaped portion 161, and is connected to the first end portion 161a and the second end portion 161b of the first arc-shaped portion 161.

[0065] The second arcuate portion 162 separates from the outer ring 20, which is contacted by the first arcuate portion 161 in the track ring. The second arcuate portion 162 is radially disposed on the side opposite to the outer ring 20 (i.e., radially inner) relative to the first arcuate portion 161. Specifically, in plan view, the outer periphery of the second arcuate portion 162 is radially inner than the outer periphery of the first arcuate portion 161, and the inner periphery of the second arcuate portion 162 is also radially inner than the inner periphery of the first arcuate portion 161. The second arcuate portion 162 is integrally connected to the first arcuate portion 161 on its axially outer side. The second arcuate portion 162 contacts the axially inner surface of the sealing member 50, thereby being supported by the sealing member 50. In this embodiment, the second arcuate portion 162 contacts the inner surface of the cover portion 53 of the sealing member 50.

[0066] Next, as a method for manufacturing bearing 1B according to this embodiment, a grease coating method will be described. The grease coating method of this embodiment includes a first coating step, a transport step, and a second coating step.

[0067] The first coating process is performed with the sealing component 50 not installed on the outer ring 20. That is, grease is applied with the annular space between the inner ring 10 and the outer ring 20 open in the axial direction and the rolling element 30 and the retainer 40 exposed.

[0068] In the first coating process, at the first coating position in the grease-coating manufacturing apparatus, the outer ring 20 is rotated around a common axis O, while grease is ejected from the first nozzle. At this time, the position of the first nozzle is adjusted so that the ejected grease contacts the axial end of the protrusion 22 on the inner circumferential surface of the outer ring 20. Because the outer ring 20 is rotated relative to the first nozzle while the grease is ejected, the grease ejected from the first nozzle extends into an arc shape. This forms the first arc-shaped portion 161.

[0069] In the transport process, the bearing that has completed the first coating process is transported to a second coating position in the manufacturing device, which is different from the first coating position.

[0070] In the second coating process, the outer ring 20 is rotated around a common axis O at the second coating position, while grease is ejected from a second nozzle, which is different from the first nozzle. At this time, the position of the second nozzle is adjusted so that the ejected grease contacts the first arc-shaped portion 161 from the outer side in the axial direction and the inner side in the radial direction. Since the outer ring 20 is rotated relative to the second nozzle while the grease is ejected, the grease ejected from the second nozzle extends into an arc shape. Thus, the second arc-shaped portion 162 is formed.

[0071] Based on the above, the grease application is completed. Subsequently, the sealing member 50 is inserted axially from the outside into the annular space between the inner ring 10 and the outer ring 20, and the sealing member 50 is assembled onto the outer ring 20, thus completing bearing 1B. Furthermore, it is desirable that, during the second coating process, the first coating process is performed on the next bearing at the first coating location.

[0072] As explained above, the bearing 1B of this embodiment includes a grease-filled grease 160, which has a single arc-shaped portion 161 extending circumferentially in an arc shape at predetermined positions in the axial and radial directions and contacting the outer ring 20, and a single second arc-shaped portion 162 extending circumferentially in an arc shape at a position different in the axial and radial directions from the first arc-shaped portion 161. The first end portion 161a of the first arc-shaped portion 161 is spaced apart from the second end portion 161b in the circumferential direction. The first end portion 162a of the second arc-shaped portion 162 is also spaced apart from the second end portion 162b in the circumferential direction. With this configuration, it is possible to prevent the formation of overlapping portions in the first arc-shaped portion 161 and the second arc-shaped portion 162. Thus, the same effect as in the first embodiment is achieved.

[0073] Furthermore, when filling with the desired amount of grease, compared to the case where only the first arc-shaped portion is provided, the volume of the first arc-shaped portion 161 can be reduced accordingly to include both the first arc-shaped portion 161 and the second arc-shaped portion 162. Therefore, by forming the first arc-shaped portion 161 earlier than the second arc-shaped portion 162 during grease application, it is difficult for the first arc-shaped portion 161 to collapse due to its own weight. Additionally, by providing the second arc-shaped portion 162, it is supported by the sealing member 50, and the first arc-shaped portion 161 is supported not only by the outer ring 20 but also by the sealing member 50 via the second arc-shaped portion 162. Therefore, the filled grease 160 as a whole becomes less likely to collapse from its immediately applied shape due to its own weight. Therefore, it is possible to prevent the filled grease 160 from making excessive contact with the rolling element 30 and the retainer 40. Thus, a lower torque in the bearing 1B can be achieved.

[0074] The second arc-shaped portion 162 spans the gap between the first end portion 161a and the second end portion 161b of the first arc-shaped portion 161. According to this configuration, since the filling grease 160 is disposed throughout the circumferential direction, compared to a configuration where the filling grease is not disposed in a portion of the circumferential direction, the filling grease 160 can be uniformly disposed throughout the circumferential direction of the bearing 1B. Furthermore, since the first end portion 161a and the second end portion 161b of the first arc-shaped portion 161 are connected to and supported by the second arc-shaped portion 162, the collapse of the filling grease 160 due to external interference or the like can be suppressed.

[0075] The sealing member 50 is fitted onto the outer ring 20 of the raceway ring that is in contact with the filling grease 160. With this configuration, the outer ring 20 and the sealing member 50 are arranged so as not to rotate relative to each other, thus preventing the filling grease 160 in contact with both sides from being agitated. Therefore, the filling grease 160 can be maintained in its freshly applied shape. Consequently, low torque in the bearing 1B can be achieved.

[0076] The second arc-shaped portion 162 is radially positioned on the side opposite to the outer ring 20 relative to the first arc-shaped portion 161. According to this configuration, compared to a configuration where the first and second arc-shaped portions are axially side-by-side, a space for the first arc-shaped portion 161 can be provided radially outward of the second arc-shaped portion 162, placing the first arc-shaped portion 161 further outward axially. This prevents the filled grease 160 from making excessive contact with the rolling element 30 and the retainer 40. Consequently, a lower torque is achieved in the bearing 1B.

[0077] According to the manufacturing method of bearing 1B of this embodiment, the cycle time at each coating position can be shortened. Therefore, the manufacturing efficiency of bearing 1B can be improved. In addition, in the manufacturing method in which the bearing is rotated while the grease is applied in an arc shape, there is no need for equipment that drives the nozzle radially relative to the bearing, thus simplifying the structure of the grease coating apparatus.

[0078] [Fourth Implementation Method] Reference Figure 8 The fourth embodiment of the present invention will now be described. Furthermore, the configuration, except as described below, is the same as that of the first embodiment.

[0079] Figure 8 This is a cross-sectional view of the rolling bearing according to the fourth embodiment. Figure 8 In the fourth embodiment shown, bearing 1C includes a second grease 65 in addition to the filler grease 60. This second grease 65 is disposed on the side opposite to the filler grease 60 in the axial direction relative to the rolling element 30. That is, the second grease 65 is disposed on the same side in the axial direction as the main body 41 of the retainer 40 relative to the rolling element 30. The second grease 65 is disposed between the rolling element 30 and the sealing member 50. The second grease 65 is disposed in the annular space between the inner ring 10 and the outer ring 20. The second grease 65 contacts the contact object of the filler grease 60 in the inner ring 10 and the outer ring 20 (the outer ring 20 in this embodiment). Like the filler grease 60, the second grease 65 contacts one of the inner ring 10 and the outer ring 20, and separates from the other. The second grease 65 separates from the rolling element 30 and the retainer 40. The second grease 65 extends circumferentially around a common axis O. Another grease 65 contacts the portion of the inner circumferential surface of the protrusion 22 of the outer ring 20 that is further outward than the rolling surface 23 of the outer ring.

[0080] However, the composition of the other grease is not limited to the above-described composition. The other grease may also contact the inner ring 10 and separate from the outer ring 20. Furthermore, the other grease may also contact at least one of the rolling elements 30 and the retainer 40. Moreover, the other grease may not be circumferentially oriented. For example, the other grease may be circumferentially oriented or may be arranged in a dotted pattern along the circumferential direction.

[0081] According to this embodiment, the total amount of grease disposed in the bearing 1C can be increased by using another grease 65. Therefore, a bearing 1C with a long service life can be provided.

[0082] [Fifth Implementation Method] Reference Figure 9 The fifth embodiment of the present invention will now be described. Furthermore, the configuration, except as described below, is the same as that of the first embodiment.

[0083] Figure 9 This is a cross-sectional view of the rolling bearing according to the fifth embodiment. Figure 9 In the fifth embodiment shown, the bearing 1D includes a second grease 66 in addition to the filler grease 60. This second grease 66 is supported by a retainer 40. The second grease 66 is disposed in a recess between a pair of claws 42 on the side of the retainer 40 opposite to the rolling element 30. In the illustrated example, the second grease 66 contacts the main body 41 of the retainer 40, but it may also contact the claws 42. The second grease 66 is separate from the rolling element 30 and the filler grease 60. Furthermore, the second grease 66 may be disposed in all or only a portion of the recesses of the retainer 40.

[0084] According to this embodiment, the total amount of grease disposed in the bearing 1D can be increased by using another grease 66. Therefore, a bearing 1D with a long service life can be provided.

[0085] Furthermore, the present invention is not limited to the embodiments described above with reference to the accompanying drawings, and various modifications can be considered within its technical scope. 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. Moreover, the filling grease 60, 60A, 160 contacts the outer ring 20, which is a fixed ring. However, the track ring contacted by the filling grease may not be a fixed ring. That is, the inner ring may be provided as a fixed ring, the outer ring as a rotating ring, and the filling grease contacts the inner ring, which is a fixed ring. Alternatively, the inner ring may be provided as a fixed ring, the outer ring as a rotating ring, and the filling grease contacts the outer ring, which is a rotating ring. In this case, the filling grease rotates together with the outer ring, but even if centrifugal force acts on the filling grease, the radially outward displacement of the grease is limited by the outer ring, thus maintaining the filling grease in its freshly applied shape. However, it is desirable that the filling grease contacts the track ring in which sealing components are installed in the inner and outer rings.

[0086] Furthermore, in the third embodiment described above, the volume ratio of the first arc-shaped portion 161 and the second arc-shaped portion 162 of the grease filling 160 is not particularly limited. For example, the cross-sectional areas of the first arc-shaped portion 161 and the second arc-shaped portion 162 may be equal or different from each other.

[0087] Furthermore, in the third embodiment described above, the filling grease 160 has two arc-shaped portions 161 and 162, but the grease can also be applied in three or more applications, thereby having three or more arc-shaped portions. However, when the grease is applied in multiple applications, it is desirable that each arc-shaped portion is formed in the same manner as the arc-shaped portions 161 and 162 described above, with a gap between its two ends.

[0088] Furthermore, in the above embodiments, a fan motor is exemplified as a rotating device, but the rotating device is not limited to this. For example, the present invention can also be applied to at least one of the spindle motor and the swing arm of a hard disk drive as a rotating device.

[0089] Furthermore, without departing from the spirit of the present invention, the constituent elements in the above embodiments can be appropriately replaced with well-known constituent elements, and the above embodiments can also be appropriately combined. For example, the wire-drawing portion 63 of the second embodiment may be connected to at least one of the first arc-shaped portion 161 and the second arc-shaped portion 162 of the second embodiment. For example, the bearing 1A of the second embodiment or the bearing 1B of the third embodiment may be provided with another grease 65 of the fourth embodiment or another grease 66 of the fifth embodiment.

[0090] Symbol Explanation 1, 1A, 1B, 1C, 1D Rolling Bearings 2 Rotating equipment 3-axis (rotational body) 4. Frame (Support) 10 Inner Circle 20 Outer ring 30 Rolling element 50 Sealing components 60, 60A, 160 Filler Grease (Grease) 61. Arc-shaped part 61a The first end of the arc-shaped portion 61b The second end of the arc-shaped portion 63. Wire drawing section 65 Another type of grease 161 First arc-shaped portion (arc-shaped portion) 161a The first end of the first arc-shaped portion (the first end of the arc-shaped portion) 161b The second end of the first arc-shaped portion (the second end of the arc-shaped portion) 162 Second arc-shaped portion (another arc-shaped portion) 162a The first end of the second arc-shaped portion (the first end of the other arc-shaped portion) 162b The second end of the second arc-shaped portion (the second end of the other arc-shaped portion) O Common axis.

Claims

1. A rolling bearing, comprising: The inner and outer rings are arranged coaxially with each other; Rolling elements disposed between the inner ring and the outer ring; and Grease disposed between the inner and outer rings. The grease has a single arc-shaped portion that extends in an arc shape about the common axis at a predetermined position in the axial direction and radial direction centered on the common axis of the inner and outer rings, and contacts one of the inner and outer rings. The first end of the arc-shaped portion is spaced apart from the second end of the arc-shaped portion in the circumferential direction, and the arc-shaped portion extends from the first end by more than 180° but less than 360° to reach the second end.

2. The rolling bearing according to claim 1, wherein, One of the inner ring and the outer ring is set as a fixed ring.

3. The rolling bearing according to claim 1 or claim 2, wherein, The outer ring is one of the inner ring and the outer ring.

4. The rolling bearing according to any one of claims 1 to 3, wherein, The grease also includes a stringing portion extending from one of the first end and the second end of the arc-shaped portion. The wire drawing section crosses the gap between the first end and the second end of the arc-shaped section and is connected to the first end and the second end of the arc-shaped section.

5. The rolling bearing according to any one of claims 1 to 4, wherein, It also includes a sealing component that covers the space between the inner and outer rings from the outside in the axial direction. The grease also includes a single, additional arc-shaped portion that extends in an arc shape in the circumferential direction at a position different from the arc-shaped portion in the axial and radial directions, connects to the arc-shaped portion, and contacts the sealing member. The first end of the other arc-shaped portion is positioned at a circumferential gap relative to the second end of the other arc-shaped portion.

6. The rolling bearing according to claim 5, wherein, The other arc-shaped portion spans the gap between the first end of the arc-shaped portion and the second end of the arc-shaped portion.

7. The rolling bearing according to claim 5 or claim 6, wherein, The sealing component is assembled on one of the inner ring and the outer ring.

8. The rolling bearing according to any one of claims 5 to 7, wherein, The other arcuate portion is positioned radially opposite to one of the inner and outer rings, relative to the arcuate portion.

9. The rolling bearing according to any one of claims 1 to 8, wherein, It also has another grease, which is disposed on the opposite side of the rolling element in the axial direction.

10. A rotating device, comprising: A rotatable rotating body; A support that rotatably supports the rotating body; and A rolling bearing according to any one of claims 1 to 9, located between the rotating body and the supporting body.

11. A method for manufacturing a rolling bearing, comprising the method for manufacturing a rolling bearing according to any one of claims 5 to 8, and including: In the first coating process, at the first coating position, grease is expelled from the first nozzle to form the arc-shaped portion, and In the second coating process, at a second coating position different from the first coating position, grease is expelled from a second nozzle different from the first nozzle to form the other arc-shaped portion.

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