Rolling bearing and rotation device

Abstract

To provide a rolling bearing capable of suppressing generation of slippage of a bearing ring.SOLUTION: A rolling bearing 1 comprises an inner ring 10 and an outer ring 20 arranged coaxially with each other, and a rolling element 30 arranged between the inner ring 10 and the outer ring 20. The outer ring 20 is mounted on a base part 120. The outer ring 20 comprises a resin cover 60 having a fitting part 27 that is fitted into the base part 120 so as not to rotate relative to the base part.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a rolling bearing and a rotating device.

Background Art

[0002] Generally, a rolling bearing includes an outer ring and an inner ring arranged coaxially, a plurality of rolling elements disposed between the inner ring and the outer ring, and a cage that rotatably holds each rolling element in a state where the plurality of rolling elements are evenly arranged in the circumferential direction. This type of rolling bearing comes in a wide variety of forms depending on the type of load to be supported (radial load, axial load, etc.) and the application, and is incorporated into various rotating devices such as fan motors and used. In particular, a ball bearing that uses balls as rolling elements is suitably used for a rotating device having a shaft portion of a rotating body that rotates at high speed.

[0003] With the recent increase in the rotational speed of rotating devices, due to the rotation of the raceway ring, a phenomenon of slippage occurring between the mounted member on which the raceway ring is mounted and the mounting surface of the raceway ring has become a problem. When slippage of the raceway ring occurs, noise, wear powder may be generated, or the sliding portion may heat up. In this case, problems such as damage to the transfer surface of the raceway ring and the balls due to the intrusion of wear powder, or problems such as deterioration of the grease inside the rolling bearing due to the heat generation of the sliding portion and a decrease in the life of the rolling bearing may occur. The same problems may occur when creep or fretting occurs.

[0004] In order to suppress the occurrence of the above problems, there is a technique of applying grease to the mounting surface of the rolling bearing (see, for example, Patent Document 1). It is said that this can reduce the friction coefficient on the mounting surface and suppress creep.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, even if grease is applied to the mounting surface of the raceway ring, it is insufficient to suppress the slipping of the raceway ring itself. Further, when the grease applied to the mounting surface of the raceway ring dries up, there is a problem that the above-mentioned defect may occur. Therefore, in a rotating device provided with a rolling bearing, there is still a problem of suppressing the occurrence of slipping of the raceway ring of the rolling bearing.

[0007] Therefore, the present invention provides a rolling bearing capable of suppressing the occurrence of slipping of a raceway ring, and a rotating device provided with the rolling bearing.

Means for Solving the Problems

[0008] The rolling bearing according to the first aspect of the present invention includes an inner ring and an outer ring arranged coaxially with each other, and rolling elements arranged between the inner ring and the outer ring, and is a rolling bearing in which one of the inner ring and the outer ring is mounted on a member to be mounted, and the one raceway ring includes a resin portion having a fitting portion that fits non-rotatably with respect to the member to be mounted.

[0009] According to the first aspect, rotation of one raceway ring with respect to the member to be mounted can be restricted. Further, since the fitting portion is provided in the resin portion of one raceway ring, the workability of one raceway ring is improved as compared with the case where the fitting portion is provided in the metal member of one raceway ring, and a decrease in the roundness of one raceway ring due to formation in a complicated shape can be suppressed. Therefore, it is possible to suppress the occurrence of slipping of the raceway ring while suppressing a decrease in the accuracy of the rolling bearing.

[0010] The rolling bearing according to the second aspect of the present invention is the rolling bearing according to the first aspect, wherein the one raceway ring has an end face facing outward in the axial direction, and the fitting portion may be provided on the end face.

[0011] If one of the raceway rings is an outer ring, providing a fitting portion on the outer peripheral surface, which is the mounting surface of the outer ring, may reduce the workability when forming the outer peripheral surface and deteriorate the dimensional accuracy of the outer peripheral surface. The same applies when one of the raceway rings is an inner ring. According to the second aspect, it is possible to suppress deterioration of the dimensional accuracy of the mounting surface of one of the raceway rings. Therefore, it is possible to suppress a decrease in the accuracy of the rolling bearing.

[0012] The rolling bearing according to the third aspect of the present invention is the rolling bearing according to the first aspect, wherein the one raceway ring has a circumferential surface facing the mounted member side in the radial direction, and the fitting portion may be provided on the circumferential surface.

[0013] According to the third aspect, in the process of mounting the rolling bearing on the mounted member, the fitting state between the fitting portion and the fitted portion of the mounted member can be visually confirmed. Therefore, a rolling bearing having excellent workability when mounted on the mounted member can be obtained.

[0014] The rolling bearing according to the fourth aspect of the present invention is the rolling bearing according to any one of the first to third aspects, wherein the one raceway ring includes a metal raceway ring body on which a raceway surface for the rolling elements to roll is formed, and the resin portion may be a resin cover covering the raceway ring body.

[0015] According to the fourth aspect, since the contact portion of one of the raceway rings with the rolling elements is formed of a metal material, it is possible to suppress a decrease in the durability of the rolling bearing due to the provision of the resin portion. In addition, since the resin portion can be integrally insert-molded with the raceway ring body, it is possible to suppress displacement of the resin portion with respect to the raceway ring body and accurately mold one of the raceway rings. Furthermore, since the raceway ring body is covered with the resin cover, it is possible to prevent electric corrosion.

[0016] The rolling bearing according to the fifth aspect of the present invention is the rolling bearing according to the fourth aspect, wherein the resin cover may be disposed only at one position in the axial direction rather than the central position in the axial direction on the raceway surface of the one raceway ring.

[0017] According to the fifth aspect, as compared with the configuration in which the resin cover is arranged over the entire axial length of one of the track wheels, it is possible to reduce the amount of resin used for the resin cover, and the manufacturing cost can be reduced.

[0018] The rolling bearing according to the sixth aspect of the present invention may be a rolling bearing according to any one of the first to third aspects, in which the entire one of the track wheels is the resin part.

[0019] According to the sixth aspect, as compared with the case where a part of one of the track wheels is made of metal, the forming of one of the track wheels becomes easy, and the productivity of one of the track wheels can be improved. Further, it is possible to suppress the occurrence of electric corrosion in the rolling bearing due to an electric current flowing inside the rolling bearing.

[0020] The rolling bearing according to the seventh aspect of the present invention may be a rolling bearing according to the sixth aspect, in which the other track wheel of the inner ring and the outer ring may be made of resin.

[0021] According to the seventh aspect, as compared with the case where a part of the other track wheel is made of metal, the forming of the other track wheel becomes easy, and the productivity of the other track wheel can be improved. Further, by forming the inner ring and the outer ring with a resin material having less moisture absorption, dimensional changes due to moisture absorption of the inner ring and the outer ring are suppressed. Therefore, a rolling bearing suitable for use in water can be obtained.

[0022] The rolling bearing according to the eighth aspect of the present invention may be a rolling bearing according to any one of the first to seventh aspects, in which the resin part may contain potassium titanate whiskers.

[0023] According to the eighth aspect, the resin part can be made into a member excellent in wear resistance and surface smoothness. Further, as compared with the case where the resin part contains glass fiber or carbon fiber as a reinforcing material, the workability when forming the resin part by cutting, grinding, or the like can be improved.

[0024] The rolling bearing according to the ninth aspect of the present invention is the rolling bearing according to any one of the first to eighth aspects, wherein the resin material forming the resin portion may be formed of one or more of polybutylene terephthalate, polyphenylene sulfide, and polyether ether ketone.

[0025] According to the ninth aspect, moisture absorption of the resin portion and dimensional changes of one of the raceway rings due to moisture absorption can be suppressed. Therefore, a rolling bearing suitable for use in water can be obtained.

[0026] The rotating device according to the tenth aspect of the present invention includes the rolling bearing according to any one of the first to ninth aspects, the mounted member having a fitted portion that fits into the fitting portion, and a rotating body that is supported by the mounted member via the rolling bearing and is rotatably disposed with respect to the mounted member.

[0027] According to the tenth aspect, a rotating device in which slippage of the raceway ring of the rolling bearing is suppressed can be provided.

[0028] The rotating device according to the eleventh aspect of the present invention includes the rolling bearing according to the fourth or fifth aspect, the mounted member having a fitted portion that fits into the fitting portion, a rotating body that is supported by the mounted member via the rolling bearing and is rotatably disposed with respect to the mounted member, and a biasing member that biases the other raceway ring of the inner ring and the outer ring in one axial direction, and the resin cover has a contact portion with the mounted member only at a position in the other axial direction from the central position in the axial direction on the raceway surface.

[0029] In the eleventh aspect, the rolling elements receive the biasing force of the biasing member and contact one axial position of the raceway surface rather than the central position in the axial direction thereof. Here, if the resin cover is radially sandwiched between the contact point with the rolling elements on the raceway surface and the member to be mounted, when distortion occurs in the resin cover and the distortion spreads to the raceway ring body, the contact point with the rolling elements on the raceway surface may change, possibly causing malfunction of the rolling bearing. According to the tenth aspect, since the resin cover does not contact the member to be mounted at one axial position of the raceway surface rather than the central position in the axial direction, even if distortion occurs in the resin cover near the contact point between the outer ring and the rolling elements, it is possible to avoid the spread of the distortion to the raceway ring body. Therefore, it is possible to suppress the change in the contact point with the rolling elements on the raceway surface and the occurrence of malfunction of the rolling bearing.

Advantages of the Invention

[0030] According to the present invention, the occurrence of slippage of the raceway ring can be suppressed.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0032] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to components having the same or similar functions. And the redundant description of these components may be omitted.

[0033] FIG. 1 is a longitudinal sectional view showing the fan motor of the embodiment. The fan motor 100 shown in FIG. 1 is an example of a rotating device. The fan motor 100 includes a rotating body 110 having a shaft portion 111, a base portion 120 that supports the rotating body 110, a drive portion 130 that rotates the rotating body 110 with respect to the base portion 120, and a pair of rolling bearings 1 that are attached to the base portion 120 and rotatably support the shaft portion 111. In the following description, the rolling bearing 1 may be simply referred to as the bearing 1. Also, in the present embodiment, the direction in which the central axis O of the shaft portion 111 of the rotating body 110 extends is referred to as the axial direction, the direction that is orthogonal to the central axis O and extends radially from the central axis O is referred to as the radial direction, and the direction that circulates around the central axis O is referred to as the circumferential direction. Further, one of the directions that are parallel to the axial direction and point in opposite directions to each other is defined as the upward direction, and the other is defined as the downward direction.

[0034] The base portion 120 has a cylindrical portion 121 that extends in the axial direction. The shaft portion 111 of the rotating body 110 is inserted into the cylindrical portion 121. The rotating body 110 is disposed above the base 120. The rotating body 110 includes a shaft portion 111 and a fan 112 connected to the shaft portion 111 outside the cylindrical portion 121. The fan 112 is fixed to the upper end portion of the shaft portion 111. The fan 112 includes a flange 113 that projects radially outward from the upper end portion of the shaft portion 111 and extends over the entire circumferential direction, a peripheral wall 114 that extends downward from the entire outer peripheral edge of the flange 113, and a plurality of blades 115 that are arranged at intervals in the circumferential direction on the radially outer side of the peripheral wall 114. The peripheral wall 114 surrounds the cylindrical portion 121 over the entire circumference at a radially spaced distance from the cylindrical portion 121.

[0035] The drive unit 130 is a motor. The drive unit 130 includes a stator 131 having a coil and a rotor 132 having a magnet. The stator 131 is fixed to the base 120 outside the shaft portion 111. The rotor 132 is fixed to the peripheral wall 114 of the fan 112 on the radially outer side of the stator 131.

[0036] A pair of bearings 1 are respectively interposed between the inner peripheral surface of the cylindrical portion 121 and the outer peripheral surface of the shaft portion 111. Each bearing 1 is a ball bearing. The pair of bearings 1 are arranged coaxially with each other. The pair of bearings 1 are arranged side by side at an axial interval.

[0037] The pair of bearings 1 are a first bearing 1A and a second bearing 1B. The first bearing 1A is inserted into the cylindrical portion 121 from the rotating body 110 side. The end surface facing downward of the outer ring 20 of the first bearing 1A is in contact with the stepped surface 122 of the inner peripheral surface of the cylindrical portion 121. The first bearing 1A is in contact with a biasing member 101. The biasing member 101 is a coil spring. The biasing member 101 is arranged on the opposite side of the stepped surface 122 with the first bearing 1A interposed therebetween. The biasing member 101 is externally inserted into the shaft portion 111 of the rotating body 110 and is arranged coaxially with the central axis O. The biasing member 101 is interposed between the inner ring 10 of the first bearing 1A and the flange 113 of the fan 112. The biasing member 101 biases the first bearing 1A downward with respect to the rotating body 110.

[0038] The second bearing 1B is inserted into the cylindrical portion 121 from the opposite side of the rotating body 110. The end face of the outer ring 20 of the second bearing 1B facing upward is in contact with the stepped surface 123 of the inner peripheral surface of the cylindrical portion 121. The displacement of the outer ring 20 of the second bearing 1B toward the rotating body 110 side is restricted by the stepped surface 123 of the inner peripheral surface of the cylindrical portion 121. The end face of the inner ring 10 of the second bearing 1B facing downward is in contact with the C-ring 103 attached to the shaft portion 111. The displacement of the inner ring 10 of the second bearing 1B in the direction away from the rotating body 110 with respect to the shaft portion 111 is restricted by the C-ring 103.

[0039] [First Embodiment] FIG. 2 is a plan view of the rolling bearing according to the first embodiment. FIG. 3 is a longitudinal sectional view of the rolling bearing according to the first embodiment, showing a cross section taken along line III-III in FIG. 2. In FIG. 2, a part of the resin cover 60 described later is shown broken. As shown in FIGS. 2 and 3, each bearing 1 includes 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 inner ring 10 and the outer ring 20 have the central axis O as a common axis.

[0040] The inner ring 10 is provided as a rotating ring. The inner ring 10 is externally inserted into the shaft portion 111. The outer ring 20 is provided as a fixed ring. The outer ring 20 surrounds the inner ring 10 from the outside in the radial direction with an annular space provided between the outer ring 20 and the inner ring 10. The plurality of rolling elements 30 are arranged between the inner ring 10 and the outer ring 20 and are rotatably held by the cage 40. The cage 40 rotatably holds each rolling element 30 in a state where the plurality of rolling elements 30 are evenly arranged in the circumferential direction. The seal member 50 covers the annular space between the inner ring 10 and the outer ring 20 from the outside in the axial direction.

[0041] The outer ring 20 includes an outer ring body 21 (raceway ring body) and a resin cover 60 (resin part) attached to the outer ring body 21. The outer ring body 21 is formed in an annular shape from a metal material such as stainless steel or bearing steel. The width of the outer ring body 21 along the axial direction is made equal to the width of the inner ring 10 along the axial direction. The outer ring body 21 includes an inner peripheral surface 22 and an outer peripheral surface 25. The inner peripheral surface 22 faces the inner ring 10 side. The outer peripheral surface 25 faces the side opposite to the inner ring 10.

[0042] On the inner peripheral surface 22 of the outer ring body 21, an outer ring raceway surface 23 on which the rolling elements 30 roll and a fitting groove 24 for holding the seal member 50 are formed. The outer ring raceway surface 23 is recessed outward in the radial direction. The outer ring raceway surface 23 is formed in a hemispherical shape in cross-section along the outer surface of the rolling element 30 and is formed in an annular shape extending in the circumferential direction over the entire circumference of the inner peripheral surface 22 of the outer ring body 21. The outer ring raceway surface 23 is formed in a portion located at the center in the axial direction of the inner peripheral surface 22 of the outer ring body 21. The pair of fitting grooves 24 are formed at the axial ends of the inner peripheral surface 22. The fitting groove 24 is recessed inward in the radial direction. The fitting groove 24 opens across the inner peripheral surface 22 and the axial end surface of the outer ring body 21. The fitting groove 24 is formed in an annular shape extending in the circumferential direction over the entire circumference of the inner peripheral surface 22 of the outer ring body 21. The portion between the outer ring raceway surface 23 and the fitting groove 24 of the inner peripheral surface 22 of the outer ring body 21 extends in the axial direction with a constant inner diameter.

[0043] FIG. 4 is a plan view of the outer ring of the first embodiment. As shown in FIGS. 3 and 4, the resin cover 60 is mounted on the outer ring body 21 so as not to be relatively displaced. The resin cover 60 is formed of a resin material having insulating properties. As the type of resin forming the resin cover 60, it is preferably formed of one or more of polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK), which have little moisture absorption, are easy to achieve molding accuracy, and are excellent in chemical resistance. Further, it is preferable that potassium titanate whiskers are added to the resin as a reinforcing material. Potassium titanate whiskers are preferably blended in an amount of 5% to 40%, and more preferably 10% to 30%. It is desirable not to add glass fibers or carbon fibers to the resin as a reinforcing material. If hard glass fibers or carbon fibers are added to the resin, it is difficult to perform finishing processing on the resin cover after insert molding by machining such as centerless grinding, and it is easy to damage the grinding wheel and cutting tool. On the other hand, potassium titanate whiskers are softer than glass fibers and carbon fibers, and are small in both thickness and length, making machining easy. The resin to which potassium titanate whiskers are added is easier to machine than the resin alone.

[0044] The resin cover 60 is formed in a cylindrical shape. The outer peripheral surface of the resin cover 60 is the outer peripheral surface of the outer ring 20, and when the bearing 1 is inserted into the cylindrical portion 121, it is in sliding contact with the inner peripheral surface of the cylindrical portion 121. The resin cover 60 is arranged over the entire axial length of the outer ring 20. The resin cover 60 includes a peripheral wall portion 61 that covers the outer peripheral surface 25 of the outer ring body 21, and a pair of flange portions 62 that are connected to the peripheral wall portion 61 and cover the axial end surfaces of the outer ring body 21. The peripheral wall portion 61 covers the entire outer peripheral surface 25 of the outer ring body 21 from the outside in the radial direction. The peripheral wall portion 61 extends in the axial direction with a constant outer diameter. The flange portion 62 projects radially inward from the axial end of the peripheral wall portion 61. The flange portion 62 extends over the entire circumference around the central axis O. The resin cover 60 is integrally insert-molded with the outer ring body 21.

[0045] The outer ring 20 further includes a fitting portion 27 that is non-rotatably fitted to the base 120 of the rotating device. The fitting portion 27 is formed on an end face facing the outer side in the axial direction of the outer ring 20. The fitting portion 27 is provided on the resin cover 60. The fitting portion 27 is a convex portion that protrudes axially outward from the flange portion 62. The fitting portion 27 protrudes only in one axial direction. That is, the fitting portion 27 is coupled to only one of the pair of flange portions 62. A plurality (four in the illustrated example) of the fitting portions 27 are provided at equal intervals in the circumferential direction. The fitting portion 27 is formed in a columnar shape. However, the shape of the fitting portion 27 is not particularly limited as long as it can be inserted into the fitted portion 125 described later. All the fitting portions 27 are formed in the same shape as each other. All the fitting portions 27 have rotational symmetry with respect to each other about the axis O. The fitting portion 27 has a gap in the radial direction with respect to the outer peripheral edge and the inner peripheral edge of the flange portion 62 when viewed from the axial direction. However, the fitting portion may be connected to at least one of the outer peripheral edge and the inner peripheral edge of the flange portion 62 when viewed from the axial direction. Note that the fitting portion 27 overlaps the outer peripheral surface 25 of the outer ring body 21 when viewed from the axial direction, but the entire fitting portion may or may not overlap the outer ring body 21 when viewed from the axial direction.

[0046] The inner ring 10 is formed in an annular shape from a metal material such as stainless steel or bearing steel. An inner ring raceway surface 11 that is recessed radially inward is formed on the outer peripheral surface of the inner ring 10. The inner ring raceway surface 11 is formed in a hemispherical shape in a cross-sectional view so as to follow the outer surface of the rolling element 30 and is formed in an annular shape that extends in the circumferential direction over the entire circumference of the outer peripheral surface. The inner ring raceway surface 11 is formed in a portion located at the center in the axial direction of the outer peripheral surface of the inner ring 10 and is arranged to face the outer ring raceway surface 23 in the radial direction. The portion of the outer peripheral surface of the inner ring 10 excluding the inner ring raceway surface 11 extends axially with a constant outer diameter.

[0047] The plurality of rolling elements 30 are formed into spherical shapes from metallic materials such as stainless steel and bearing steel. The plurality of rolling elements 30 are arranged between the outer ring raceway surface 23 and the inner ring raceway surface 11, and are supported so as to be rollable by the outer ring raceway surface 23 and the inner ring raceway surface 11. The plurality of rolling elements 30 are kept at intervals in the circumferential direction by a cage 40.

[0048] As shown in FIG. 3, the cage 40 is integrally formed in an annular shape from a synthetic resin or a metallic material. The cage 40 is arranged coaxially with the central axis O. The cage 40 includes an annular portion 41 formed in an annular shape and disposed below the plurality of rolling elements 30, and a plurality of column portions 42 projecting upward from the annular portion 41 and provided at intervals in the circumferential direction. The column portions 42 are arranged evenly in the circumferential direction. A pair of adjacent column portions 42 in the circumferential direction form 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 corresponding to the number of the rolling elements 30, and hold the rolling elements 30 separately so as to be rollable. Thereby, the cage 40 arranges the rolling elements 30 at equal intervals with spaces therebetween in the circumferential direction.

[0049] As shown in FIGS. 2 and 3, the seal member 50 is formed in an annular plate shape. The seal member 50 is arranged coaxially with the central axis O. The seal member 50 is attached to the outer ring 20. The seal members 50 are arranged one on each of the axial both sides with respect to the plurality of rolling elements 30. The seal member 50 includes a seal fitting portion 51 that fits into the fitting groove 24 of the outer ring body 21, and a cover portion 53 that projects radially inward from the seal fitting portion 51. The seal member 50 extends radially so as to straddle at least the center of the rolling elements 30 in plan view. The inner peripheral edge of the cover portion 53 is arranged with a gap from the outer peripheral surface of the inner ring 10. The seal member 50 is fixed to the outer ring body 21 by the seal fitting portion 51 being locked to the wall surface of the fitting groove 24.

[0050] FIG. 5 is a cross-sectional view of the fan motor according to the first embodiment, and shows an enlarged portion corresponding to the V portion of FIG. 1. As shown in FIG. 5, the bearing 1 is arranged on the fan motor 100 such that the fitting portion 27 contacts the base portion 120. The base portion 120 is formed with a fitted portion 125 that fits into the fitting portion 27 of the bearing 1. The fitted portion 125 is a recess formed in the stepped surface 122 on the inner peripheral surface of the cylindrical portion 121 of the base portion 120. The fitted portion 125 is formed in advance on the stepped surface 122 before the bearing 1 is mounted on the cylindrical portion 121. The fitting portions 27 are inserted into the fitted portions 125 one by one. By inserting the fitting portion 27 into the fitted portion 125, the end face of the outer ring 20 (the flange portion 62 of the resin cover 60) makes surface contact with the periphery of the fitted portion 125 on the stepped surface 122. On the stepped surface 122, the same number of fitted portions 125 as the fitting portions 27 may be provided, or more (for example, an integral multiple of the fitting portions 27) may be provided than the fitting portions 27. It is desirable that each fitted portion 125 is formed so that there is substantially no gap in the circumferential direction and the radial direction with respect to the fitting portion 27 inserted into the fitted portion 125. Since there is no gap in the circumferential direction between the fitted portion 125 and the fitting portion 27, the fitting portion 27 is fitted to the cylindrical portion 121 so as not to be relatively rotatable. However, the fitted portion 125 may have a slight gap in the circumferential direction with respect to the fitting portion 27, and even in this configuration, the fitting portion 27 is fitted to the cylindrical portion 121 so as not to be relatively rotatable by a predetermined angle or more. In FIG. 5, the relationship between the first bearing 1A and the stepped surface 122 is shown, but the relationship between the second bearing 1B and the stepped surface 123 is the same.

[0051] As described above, the bearing 1 of the present embodiment is configured such that the outer ring 20 is mounted on the base portion 120 of the fan motor 100, and includes a resin cover 60 having a fitting portion 27 that fits the outer ring 20 to the base portion 120 so as not to be relatively rotatable. According to this configuration, rotation of the outer ring 20 with respect to the base portion 120 can be restricted. Further, since the fitting portion 27 is provided on the resin cover 60 of the outer ring 20, the workability of the outer ring 20 is improved as compared with the case where the fitting portion is provided on the metal member of the outer ring, and a decrease in the roundness of the outer ring 20 due to formation in a complex shape can be suppressed. Therefore, it is possible to suppress the occurrence of slippage of the outer ring 20 while suppressing a decrease in the accuracy of the bearing 1.

[0052] If a fitting portion is provided on the outer peripheral surface which is the mounting surface of the outer ring, the workability in forming the outer peripheral surface may be reduced and the dimensional accuracy of the outer peripheral surface may deteriorate. According to the present embodiment, since the fitting portion 27 is provided on the end surface facing the outer side in the axial direction of the outer ring 20, it is possible to suppress deterioration of the dimensional accuracy of the outer peripheral surface which is the mounting surface of the outer ring 20. Therefore, a decrease in the accuracy of the bearing 1 can be suppressed.

[0053] A plurality of fitting portions 27 are provided at equal intervals in the circumferential direction. With this configuration, the shape of the resin cover 60 can have rotational symmetry, and deformation after molding of the resin cover 60 can be suppressed. Also, the force applied from the cylindrical portion 121 to the outer ring 20 can be evenly dispersed, and deformation of the outer ring 20 can be suppressed.

[0054] The outer ring 20 includes a metal outer ring body 21 on which an outer ring raceway surface 23 is formed. The resin cover 60 covers the outer ring body 21. According to this configuration, since the contact portion of the outer ring 20 with the rolling elements 30 is formed of a metal material, it is possible to suppress a decrease in the durability of the bearing 1 due to the provision of the resin cover 60. Also, since the resin cover 60 can be insert-molded integrally with the outer ring body 21, it is possible to suppress displacement of the resin cover 60 with respect to the outer ring body 21 and to accurately mold the outer ring 20. Further, since the outer ring body 21 is covered with the resin cover 60, electric corrosion can be prevented.

[0055] The resin cover 60 contains potassium titanate whiskers. According to this configuration, the resin cover 60 can be made into a member excellent in wear resistance and surface smoothness. Also, compared with the case where the resin cover contains glass fiber or carbon fiber as a reinforcing material, the workability in molding the resin cover 60 by cutting, grinding, etc. can be improved.

[0056] The resin material forming the resin cover 60 is formed of one or more of polybutylene terephthalate, polyphenylene sulfide, and polyether ether ketone. According to this configuration, moisture absorption of the resin cover 60 and dimensional changes of the outer ring 20 due to moisture absorption can be suppressed. Therefore, the outer ring 20 suitable for use in water can be obtained.

[0057] The fitting portion 27 is provided only on one of the pair of end faces of the outer ring 20. According to this configuration, even if the internal structure of the bearing 1 is asymmetric in the axial direction, such as the shape of the cage 40 or the arrangement of the grease, by determining in advance the orientation of the internal structure of the bearing 1 and the arrangement of the fitting portion 27, it becomes possible to grasp the orientation of the internal structure of the bearing 1 from the appearance of the bearing 1.

[0058] The fan motor 100 includes a bearing 1, a base 120 having a fitted portion 125 that fits into the fitting portion 27, and a rotating body 110 that is supported by the base 120 via the bearing 1 and is rotatably arranged with respect to the base 120. According to this configuration, the fan motor 100 with suppressed slippage of the outer ring 20 of the bearing 1 can be obtained.

[0059] [Second Embodiment] The second embodiment will be described. The second embodiment is different from the first embodiment in that the entire outer ring is made of resin. The configuration other than that described below is the same as that of the first embodiment.

[0060] FIG. 6 is a longitudinal sectional view of the rolling bearing according to the second embodiment, which corresponds to FIG. 3. FIG. 7 is a plan view of the outer ring according to the second embodiment. As shown in FIGS. 6 and 7, the bearing 201 includes an inner ring 210, an outer ring 220, a plurality of rolling elements 230, and a cage 240. Note that the bearing 201 does not include the seal member 50 of the first embodiment.

[0061] The entire outer ring 220 is formed of a resin material. The outer ring 220 is formed of one or more of polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK). Potassium titanate whiskers are added to the resin forming the outer ring 220 as a reinforcing material. The potassium titanate whiskers are preferably blended in an amount of 10% to 40%.

[0062] The outer ring 220 includes an inner peripheral surface 222 and an outer peripheral surface 225. The inner peripheral surface 222 faces the inner ring 210 side. The outer peripheral surface 225 faces the side opposite to the inner ring 210. An outer ring raceway surface 223 on which the rolling elements 230 roll is formed on the inner peripheral surface 222. The portion of the inner peripheral surface 222 of the outer ring 220 excluding the outer ring raceway surface 223 extends in the axial direction with a constant outer diameter.

[0063] The outer ring 220 further includes a fitting portion 227 that is non-rotatably fitted to the base portion 120 of the fan motor 100. That is, in the present embodiment, the outer ring 220 is a resin portion having the fitting portion 227. The fitting portion 227 is formed on an end surface facing the outer side in the axial direction of the outer ring 220. The fitting portion 227 is a recess formed in the end surface of the outer ring 220. The fitting portion 227 is provided only on one end surface of the outer ring 220. A plurality (four in the illustrated example) of the fitting portions 227 are provided at equal intervals in the circumferential direction. The fitting portion 227 extends along the radial direction. The fitting portion 227 opens across the end surface of the outer ring 220 and the inner peripheral surface 222 and the outer peripheral surface 225 of the outer ring 220. However, the shape of the fitting portion 227 is not particularly limited. For example, the fitting portion 227 may not open to at least one of the inner peripheral surface 222 and the outer peripheral surface 225 of the outer ring 220. All the fitting portions 227 are formed in the same shape as each other. All the fitting portions 227 have rotational symmetry with respect to the axis O. A gate 228 is formed on the bottom surface of the fitting portion 227. The gate 228 is formed in one fitting portion 227. However, the gate 228 may be formed in a plurality of fitting portions 227. Also, the gate 228 itself may not be formed.

[0064] The inner ring 210 is formed of a resin material. The inner ring 210 is formed of one or more of polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK). Note that reference numeral 211 in the figure indicates the inner ring raceway surface.

[0065] The rolling elements 230 are formed of a non-metallic material such as ceramics, glass, or resin material. The cage 240 is formed of a resin material. For example, the cage 240 is formed of one or more of polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK).

[0066] The bearing 201 is arranged on the fan motor 100 so that the fitting portion 227 contacts the base portion 120, similar to the first embodiment. In this embodiment, on the base portion 120, convex portions are formed on the stepped surfaces 122 and 123 (see FIG. 1) of the inner peripheral surface of the cylindrical portion 121 as fitting portions that fit into the fitting portion 227 of the bearing 201. The fitting portions are formed in advance on the stepped surfaces 122 and 123 in a state before the bearing 201 is mounted on the cylindrical portion 121. The fitting portions are inserted into the fitting portion 227 one by one. When the fitting portions are inserted into the fitting portion 227, the end surface of the outer ring 220 comes into surface contact with the periphery of the fitting portions on the stepped surfaces 122 and 123. On each of the stepped surfaces 122 and 123, the number of fitting portions provided is equal to or less than the number of fitting portions 227. It is desirable that each fitting portion is formed so that there is substantially no gap in the circumferential direction and the radial direction with respect to the fitting portion 227 into which the fitting portion is inserted.

[0067] In this embodiment, the same effects as those of the first embodiment are achieved. In addition, in this embodiment, the entire outer ring 220 is a resin portion having the fitting portion 227. According to this configuration, compared with the case where a part of the outer ring is made of metal, the molding of the outer ring 220 becomes easy, and the productivity of the outer ring 220 can be improved. Furthermore, it is possible to suppress the occurrence of electrolytic corrosion in the bearing 201 due to an electric current flowing through the inside of the bearing 201.

[0068] In addition, since potassium titanate whiskers are added to the resin forming the outer ring raceway surface 223, excellent wear resistance and surface smoothness are imparted to the outer ring raceway surface 223, and a highly durable resin bearing 201 can be obtained.

[0069] The inner ring 210, the outer ring 220, and the cage 240 are formed of the above-described resin material with low moisture absorption, and the rolling elements 230 are formed of a non-metallic material. With this configuration, dimensional changes due to moisture absorption of each member of the bearing 201 are suppressed, and the bearing 201 suitable for use in water can be obtained.

[0070] A gate 228 is formed inside the fitting portion 227. According to this configuration, it is possible to suppress the gate 228 from protruding axially from the outer ring 220. Therefore, the bearing 201 can be accurately mounted on the base 120.

[0071] In the second embodiment, although the inner ring 210 and the outer ring 220 are formed of a resin material, if at least the raceway ring (the outer ring in the second embodiment) provided with the fitting portion among the inner ring and the outer ring is formed of a resin material, the above-described effects can be obtained. Also, the rolling elements do not have to be formed of a resin material and may be formed of a metal material.

[0072] [Third Embodiment] The third embodiment will be described. The third embodiment is different from the first embodiment in that the fitting portion is formed on the outer peripheral surface of the outer ring. The configuration other than that described below is the same as that of the first embodiment.

[0073] FIG. 8 is a plan view of the outer ring of the third embodiment. FIG. 9 is a cross-sectional view of the fan motor of the third embodiment and corresponds to FIG. 5. As shown in FIGS. 8 and 9, the bearing 301 includes an outer ring 320 instead of the outer ring 20 of the first embodiment. The outer ring 320 further includes a fitting portion 327 that is non-rotatably fitted to the base 120 of the rotating device. The fitting portion 327 is formed on the outer peripheral surface of the outer ring 320. The fitting portion 327 is provided on the resin cover 60. The fitting portion 327 is a convex portion that protrudes radially outward from the peripheral wall portion 61. A plurality (four in the illustrated example) of fitting portions 327 are provided at equal intervals in the circumferential direction. The fitting portion 327 has a constant width in the circumferential direction and extends in the axial direction. The fitting portion 327 extends over substantially the entire axial length of the resin cover 60. However, the shape of the fitting portion 327 is not particularly limited as long as it can be inserted into the fitted portion 126 described later. All the fitting portions 327 are formed in the same shape as each other. All the fitting portions 327 have rotational symmetry with respect to each other about the axis O.

[0074] The base 120 is formed with a fitted portion 126 that fits into the fitting portion 327 of the bearing 301. The fitted portion 126 is a recess formed on the inner peripheral surface of the cylindrical portion 121 of the base 120. The fitted portion 126 opens to the axially outer end surface of the cylindrical portion 121 and extends along the axial direction. A fitting portion 327 is inserted into the fitted portion 126 on a one-to-one basis. The number of fitted portions 126 may be the same as the number of fitting portions 327, or may be more (for example, an integer multiple of the fitting portion 327) than the fitting portion 327. It is desirable that each fitted portion 126 be formed so that there is substantially no gap in the circumferential and radial directions with respect to the fitting portion 327 inserted into the fitted portion 126. Since the fitted portion 126 has no gap in the circumferential direction with respect to the fitting portion 327, the fitting portion 327 is non-rotatably fitted to the cylindrical portion 121. However, the fitted portion 126 may have a slight gap in the circumferential direction with respect to the fitting portion 327, and even in this configuration, the fitting portion 327 is non-rotatably fitted to the cylindrical portion 121 by a predetermined angle or more.

[0075] In this embodiment, the same effects as those of the first embodiment are achieved. In addition, in this embodiment, during the process of mounting the bearing 301 on the cylindrical portion 121, the fitting state between the fitting portion 327 and the fitted portion 126 of the cylindrical portion 121 can be visually recognized. Therefore, a bearing 301 having excellent workability when mounted on the cylindrical portion 121 can be obtained.

[0076] Also, since a plurality of fitting portions 327 are provided at equal intervals in the circumferential direction, the shape of the resin cover 60 can have rotational symmetry, and deformation after molding of the resin cover 60 can be suppressed. Further, the force applied from the cylindrical portion 121 to the outer ring 320 can be evenly dispersed, and deformation of the outer ring 320 can be suppressed.

[0077] [Fourth Embodiment] The fourth embodiment will be described. In the third embodiment, the resin cover 60 is arranged over the entire axial length of the outer ring 320. In contrast, in the fourth embodiment, the resin cover 460 is arranged only on a part of the axial direction of the outer ring 420, which is different from the third embodiment. The configuration other than that described below is the same as that of the third embodiment.

[0078] FIG. 10 is a cross-sectional view of the fan motor according to the fourth embodiment, which corresponds to FIG. 5. As shown in FIG. 10, the bearing 401 includes an outer ring 420 instead of the outer ring 320 of the third embodiment. The outer ring 420 includes an outer ring body 21 and a resin cover 460 (resin part) attached to the outer ring body 21. For example, the resin cover 460 is integrally insert-molded with the outer ring body 21. However, the molding method of the resin cover 460 is not limited to this. For example, the resin cover 460 may be formed separately from the outer ring body 21 and attached to the outer peripheral surface of the outer ring body 21 by press-fitting. The resin cover 460 is disposed only at one axial position of the outer ring 420, which is axially closer to one side than the axial center position on the outer ring raceway surface 23. The axial center position on the outer ring raceway surface 23 is a location where the normal direction is parallel to the radial direction on the outer ring raceway surface 23. The resin cover 460 includes a peripheral wall portion 461 that covers the outer peripheral surface 25 of the outer ring body 21, and a flange portion 62 that is connected to the peripheral wall portion 461 and covers one axial end surface of the outer ring body 21. The peripheral wall portion 461 extends axially with a constant outer diameter. The other axial end of the peripheral wall portion 461 is located at one axial position closer to one side than the axial center position on the outer ring raceway surface 23. The peripheral wall portion 461 covers the entire outer peripheral surface of the outer ring body 21. The flange portion 62 is connected to one axial end of the peripheral wall portion 461. A fitting portion 327 is provided on the peripheral wall portion 461.

[0079] The bearing 401 is incorporated into the fan motor 100 as the first bearing 401A such that the resin cover 460 is located on the side opposite to the direction of the biasing force of the biasing member 101 acting on the inner ring 10. Thereby, the resin cover 460 is disposed only at the position on the biasing member 101 side in the axial direction, which is axially closer to one side than the axial center position on the outer ring raceway surface 23. In other words, the resin cover 460 has a contact portion with the cylindrical portion 121 only at the position on the biasing member 101 side in the axial direction, which is axially closer to one side than the axial center position on the outer ring raceway surface 23. The displacement of the first bearing 401A axially inward with respect to the cylindrical portion 121 is restricted by the end of the outer ring body 21 abutting against the stepped surface 122 of the cylindrical portion 121.

[0080] In this embodiment, the same effects as those of the third embodiment are achieved. In addition to this, the following operational effects are achieved in this embodiment. The rolling element 30 receives the biasing force of the biasing member 101 and contacts a position on one side in the axial direction (downward in FIG. 10) of the outer ring raceway surface 23 rather than the central position in the axial direction thereof. Here, if the resin cover is radially sandwiched between the contact point with the rolling element 30 on the outer ring raceway surface 23 and the cylindrical portion 121, when distortion occurs in the resin cover and the distortion spreads to the outer ring body 21, the contact point between the rolling element 30 and the outer ring raceway surface 23 may change, resulting in a malfunction of the first bearing 401A. According to this embodiment, since the resin cover 460 does not contact the cylindrical portion 121 at a position on one side in the axial direction of the outer ring raceway surface 23, even if distortion occurs in the resin cover 460 in the vicinity of the contact point between the outer ring 420 and the rolling element 30, it is possible to avoid the spread of the distortion to the outer ring body 21. Therefore, it is possible to suppress a change in the contact point between the rolling element 30 and the outer ring raceway surface 23 and the occurrence of a malfunction of the first bearing 401A.

[0081] In this embodiment, the resin cover 460 is arranged only on a part in the axial direction of the outer ring 410 to limit the position of the contact portion between the resin cover 460 and the cylindrical portion 121, but the present invention is not limited to this configuration. For example, the outer peripheral surface may be reduced in diameter so as to avoid contact with the cylindrical portion at a part in the axial direction of the resin cover, thereby limiting the position of the contact portion between the resin cover and the cylindrical portion.

[0082] The present invention is not limited to the above-described embodiments described with reference to the drawings, and various modifications can be considered within the technical scope thereof. For example, in the above embodiment, a fan motor is exemplified as the rotating device, but the rotating device is not limited thereto. For example, the present invention may be applied to a dental handpiece, a spindle motor of a hard disk drive, or the like as the rotating device. Further, in the above embodiment, the inner ring is provided as a rotating ring and the outer ring is provided as a fixed ring. However, the inner ring may be provided as a fixed ring and the outer ring may be provided as a rotating ring.

[0083] In the above-described embodiment, the fitting portion is provided on the outer ring, but the fitting portion may be provided on the inner ring, and the fitted portion may be provided on the rotating body.

[0084] In the above-described embodiment, the fitting portions 27 and 227 are provided only at one axial end of the outer rings 20 and 220, but the present invention is not limited to this configuration. That is, the fitting portions may be provided at both axial ends of the outer ring.

[0085] In addition, within the scope not departing from the gist of the present invention, it is possible to appropriately replace the constituent elements in the above-described embodiments with well-known constituent elements, and the above-described embodiments may also be appropriately combined. For example, in the resin outer ring of the second embodiment, instead of the concave fitting portion, the convex fitting portion of the first embodiment may be provided. Further, in the resin cover of the outer ring of the first embodiment, instead of the convex fitting portion, the concave fitting portion of the second embodiment may be provided. In this case, by forming the fitting portion by penetrating the flange portion of the resin cover in the axial direction, the fitting portion can be used as a portion where the ejector sleeve of the mold used when insert molding the resin cover abuts against the end face of the outer ring body. Further, in the resin cover of the outer ring of the third embodiment or the fourth embodiment, instead of the convex fitting portion, a concave fitting portion may be provided. Further, the first embodiment or the second embodiment and the third embodiment may be combined to provide the fitting portion on both the end face and the outer peripheral surface of the resin portion.

Explanation of Reference Numerals

[0086] 1, 201, 301, 401... bearings 10, 210... inner rings 20, 220, 320, 420... outer rings (one of the raceways) 21... outer ring body (raceway body) 23... outer ring raceway surface (raceway surface) 27, 227, 327... fitting portions 30, 230... rolling elements 60, 460... resin covers (resin portions) 101... biasing members 110... rotating bodies 120... bases (mounted members) 125... fitted portions

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; Equipped with A rolling bearing in which one of the inner ring and the outer ring is mounted to a mounting member, The one raceway includes a resin portion having a fitting portion that fits into the mounted member so as not to rotate relative to the mounted member. Rolling bearing.

2. The one raceway has an end surface facing outward in the axial direction, The fitting portion is provided on the end surface.

2. The rolling bearing according to claim 1.

3. The one raceway has a peripheral surface facing the mounted member in the radial direction, The fitting portion is provided on the peripheral surface.

2. The rolling bearing according to claim 1.

4. the one raceway includes a metal raceway body having a raceway surface on which the rolling elements roll, The resin portion is a resin cover that covers the raceway body.

2. The rolling bearing according to claim 1.

5. the resin cover is disposed at only one position in the axial direction relative to a center position of the raceway surface of the one raceway, 5. The rolling bearing according to claim 4.

6. The entire one of the raceways is the resin portion.

2. The rolling bearing according to claim 1.

7. The other of the inner ring and the outer ring is made of resin.

7. A rolling bearing according to claim 6.

8. The resin portion contains potassium titanate whiskers.

2. The rolling bearing according to claim 1.

9. The resin material forming the resin portion is formed of one or more of polybutylene terephthalate, polyphenylene sulfide, and polyether ether ketone.

9. A rolling bearing according to claim 8.

10. A rolling bearing according to any one of claims 1 to 9; the mounting member having a fitted portion that fits into the fitting portion; A rotating body supported by the mounting member via the rolling bearing and arranged rotatably relative to the mounting member; A rotating device comprising:

11. A rolling bearing according to claim 4 or claim 5; the mounting member having a fitted portion that fits into the fitting portion; A rotating body supported by the workpiece via the rolling bearing and rotatably disposed relative to the workpiece; a biasing member that biases the other of the inner ring and the outer ring in one axial direction; Equipped with the resin cover has a contact portion with the mounted member only at a position on the raceway surface other than a center position in the axial direction, Rotating equipment.

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