Rolling bearings

Abstract

To provide a rolling bearing that can reliably prevent peeling and creep of the insulating resin layer. [Solution] In a rolling bearing, anti-rotation grooves 13 are formed on the width surfaces 6 and 8 on which the insulating resin layer 5 is formed. These grooves extend in a circular shape that is not concentric with the outer circumference circle that forms the outline of the outer circumference of the outer ring 1 in an axial view, and the resin forming the insulating resin layer 5 enters the anti-rotation grooves 13, thereby preventing relative rotation of the insulating resin layer 5 with respect to the outer ring 1 or the inner ring 2.

Description

Technical Field

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

Background Art

[0002] In rolling bearings for electrically powered devices, such as rolling bearings that support the rotating shaft of a travel electric motor for electric vehicles, and rolling bearings that support the rotating shaft of an e-Axle in which the travel electric motor, inverter and speed reducer of an electric vehicle are integrated, electric current passes through the interior of the bearing, which generates sparks between the outer or inner ring and the rolling elements, causing the surfaces of the outer ring, inner ring and rolling elements to locally reach high temperatures and melt, which may result in electric corrosion, a phenomenon where irregularities form on the surfaces.

[0003] To prevent this electric corrosion, rolling bearings in which the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring of the rolling bearing is covered with an insulating resin layer are used (for example, Patent Document 1).

[0004] The rolling bearing of Patent Document 1 has an outer ring, an inner ring arranged radially inward of the outer ring, a plurality of balls incorporated between the outer ring and the inner ring, and an insulating resin layer formed on the outer peripheral surface of the outer ring and the width faces on both axial sides thereof. This insulating resin layer is formed by insert molding. That is, the insulating resin layer is formed on the outer peripheral surface of the outer ring and the width faces of the outer ring by setting the outer ring in a mold, closing the mold, and performing injection molding of resin.

[0005] Incidentally, when the insulating resin layer is formed on the outer ring by injection molding, the insulating resin layer undergoes molding shrinkage during cooling after injection molding, and the outer ring also shrinks due to temperature change. Here, due to the relationship between the molding shrinkage rate of the resin forming the insulating resin layer and the linear expansion coefficient of the steel material forming the outer ring, the dimensional change amount due to the molding shrinkage of the insulating resin layer is larger than the dimensional change amount accompanying the temperature drop of the outer ring. For this reason, radial misalignment occurs between the insulating resin layer on the width face of the outer ring and the width face of the outer ring, and as a result, the insulating resin layer may peel off from the width face of the outer ring.

[0006] Furthermore, if the adhesion of the insulating resin layer to the outer ring is insufficient, a phenomenon called creep may occur during the operation of the rolling bearing, where the insulating resin layer moves circumferentially relative to the outer ring, potentially causing wear or cracking of the insulating resin layer.

[0007] Therefore, in Patent Document 1, a circumferential groove extending in the circumferential direction is formed on the outer ring width surface, and the resin of the insulating resin layer is filled into the circumferential groove to prevent the insulating resin layer from peeling off from the outer ring width surface. In addition to the outer ring width surface, two circumferential grooves extending in the circumferential direction are also formed on the outer circumference surface of the outer ring, and the resin of the insulating resin layer is filled into these circumferential grooves to improve the adhesion of the insulating resin layer to the outer ring and prevent creep of the insulating resin layer. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2004-308735 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] Although the rolling bearing described in Patent Document 1 improves adhesion by allowing the resin of the insulating resin layer to fill the circumferential grooves, the manufacturing cost is high because multiple circumferential grooves are formed to improve the adhesion force. Furthermore, even if multiple circumferential grooves are formed, creep may occur if a rotational force exceeding the adhesion force is applied to the insulating resin layer.

[0010] The problem that this invention aims to solve is to provide a rolling bearing that can reliably prevent peeling and creep of the insulating resin layer. [Means for solving the problem]

[0011] To solve the above problems, this invention provides a rolling bearing with the following configuration. [Configuration 1] Outer ring and, An inner ring positioned radially inward of the outer ring, A plurality of rolling elements are incorporated between the outer ring and the inner ring, A rolling bearing having an insulating resin layer formed on the outer circumferential surface of the outer ring and the width surfaces on both sides in the axial direction, or on the inner circumferential surface of the inner ring and the width surfaces on both sides in the axial direction, On the width surface on which the insulating resin layer is formed, an anti-rotation groove is formed that extends in a circular shape, non-concentric with the outer circle that forms the outline of the outer circumference of the outer ring in an axial view. The rolling bearing is characterized in that the insulating resin layer prevents relative rotation with respect to the outer ring or the inner ring by having the resin forming the insulating resin layer enter the anti-rotation groove.

[0012] In this configuration, anti-rotation grooves are formed on the width surface where the insulating resin layer is formed. The resin forming the insulating resin layer enters these anti-rotation grooves, preventing the insulating resin layer from peeling off the width surface. Furthermore, since the anti-rotation grooves extend in a circular shape that is not concentric with the outer circumference of the outer ring, the relative rotation of the insulating resin layer with respect to the outer or inner ring can be restricted, thereby reliably preventing creep of the insulating resin layer.

[0013] [Configuration 2] The rolling bearing according to configuration 1, wherein the anti-rotation groove is an eccentric groove that extends in a circular shape, and the center line of the anti-rotation groove is located at a position radially offset from the center line of the outer circumference of the outer ring.

[0014] In this configuration, the anti-rotation groove is circular in shape, making it easy to manufacture.

[0015] [Configuration 3] The rolling bearing according to configuration 2, wherein the eccentric groove is formed to fit within the width surface.

[0016] For example, if the center line of the eccentric groove is largely offset from the center line of the outer periphery of the outer ring, the eccentric groove on the width surface will have a circular shape that is interrupted midway. In this case, when machining the eccentric groove, the cutting tool may chatter at the interrupted portion that spans the end of the outer ring width surface, making the machining difficult. In this configuration, since the entire circumference of the eccentric groove is formed on the width surface, machining is easy.

[0017] [Configuration 4] The rolling bearing according to Configuration 2 or 3, wherein the eccentric groove is formed on the width surfaces on both axial sides.

[0018] In this configuration, since the eccentric grooves are formed on the width surfaces on both axial sides, the rotational force applied to the portion of the insulating resin layer that enters the eccentric groove can be dispersed on both axial sides, and the insulating resin layer is less likely to be damaged.

[0019] [Configuration 5] The rolling bearing according to any one of Configurations 2 to 4, wherein the offset distance of the center line of the eccentric groove is 0.1 mm or more.

[0020] In this configuration, since the offset distance of the eccentric groove is sufficiently large, the rotation prevention effect is high, and creep of the insulating resin layer can be more reliably prevented.

[0021] [Configuration 6] The rolling bearing according to Configuration 1, wherein the rotation prevention groove is an elliptical groove.

[0022] In this configuration, the rotation prevention groove has an elliptical shape, and the relative rotation of the insulating resin layer with respect to the outer ring or the inner ring is restricted by the pair of arc portions corresponding to the major axis portion of the ellipse, so the rotation prevention effect is high, and creep of the insulating resin layer can be reliably prevented.

[0023] [Configuration 7] The rolling bearing according to Configuration 6, wherein the elliptical groove is formed so as to be contained within the width surface.

[0024] For example, if the length of the major axis of the elliptical groove is greater than the outer diameter of the outer ring, the elliptical groove will appear to be interrupted on the width surface. In this case, machining the elliptical groove can be difficult because the cutting tool may vibrate at the interrupted portion at the end of the width surface. In this configuration, the entire circumference of the elliptical groove is formed on the width surface, making machining easier.

[0025] [Structure 8] The rolling bearing according to configuration 6 or 7, wherein the elliptical groove is formed on the width surfaces on both sides in the axial direction.

[0026] In this configuration, since elliptical grooves are formed on the width surfaces on both axial sides, the rotational force applied to the portion of the insulating resin layer that enters the elliptical grooves can be distributed on both axial sides.

[0027] [Composition 9] A rolling bearing according to configuration 8, wherein, of the width surfaces on both sides in the axial direction where the elliptical groove is formed, the angle between the longitudinal axis direction of the elliptical groove on one width surface and the longitudinal axis direction of the elliptical groove on the other width surface is 85° or more and 95° or less.

[0028] In this configuration, the elliptical groove formed on one width surface and the elliptical groove formed on the other width surface are arranged to be perpendicular to each other, so that the rotational force applied to the insulating resin layer can be evenly distributed in the circumferential direction.

[0029] [Configuration 10] The anti-rotation groove is formed in a rectangular cross-section, as described in any of configurations 1 to 9 of the rolling bearing.

[0030] In this configuration, since the side surface of the anti-rotation groove is perpendicular to the direction of rotation, it is possible to particularly effectively prevent the insulating resin layer from lifting and peeling off axially along the tapered shape due to rotational force, compared to, for example, the case where the anti-rotation groove is formed in a tapered shape so that the opening widens.

[0031] [Composition 11] A rolling bearing according to any one of configurations 1 to 10, wherein the depth of the anti-rotation groove is 0.5 mm or more.

[0032] In this configuration, the anti-rotation groove is sufficiently deep, so there is a large area where the resin adheres closely to the anti-rotation groove, making it particularly effective in preventing the insulating resin layer from peeling off.

[0033] [Composition 12] Outer ring and, An inner ring positioned radially inward of the outer ring, A plurality of rolling elements are incorporated between the outer ring and the inner ring, The outer ring has an insulating resin layer formed on its outer circumferential surface and the width surfaces on both sides in the axial direction, or the inner ring has an insulating resin layer formed on its inner circumferential surface and the width surfaces on both sides in the axial direction. On the width surface on which the insulating resin layer is formed, an anti-rotation groove is formed that extends in a circular shape, non-concentric with the outer circle that forms the outline of the outer circumference of the outer ring in an axial view. The insulating resin layer prevents relative rotation with respect to the outer ring or the inner ring by the resin forming the insulating resin layer entering the anti-rotation groove. The anti-rotation groove is an eccentric groove that extends in a circular shape and whose center line is radially offset from the center line of the outer circumference of the outer ring, in the manufacturing method of a rolling bearing, An eccentric chuck step is performed in which the circumferential surface of the outer ring or the circumferential surface of the inner ring, on which the insulating resin layer is formed, is chucked to the lathe while being eccentric from the rotation center of the spindle of the lathe. A method for manufacturing a rolling bearing, comprising: a turning step, after the eccentric chuck step, a turning step, in which a circumferential groove is machined on the width surface using the lathe to form the eccentric groove.

[0034] In this configuration, the outer or inner ring is chucked in an eccentric position, and then the circumferential groove is machined on a lathe to form the eccentric groove, making the machining of the eccentric groove easy. [Effects of the Invention]

[0035] In this rolling bearing, an anti-rotation groove is formed on the width surface on which the insulating resin layer is formed. The resin forming the insulating resin layer enters the anti-rotation groove, preventing the insulating resin layer from peeling off the width surface. Furthermore, since the anti-rotation groove extends in a circular shape that is not concentric with the outer circumference of the outer ring, the relative rotation of the insulating resin layer with respect to the outer or inner ring can be restricted, thereby reliably preventing creep of the insulating resin layer. [Brief explanation of the drawing]

[0036] [Figure 1] Partial cross-sectional view of a rolling bearing according to the first embodiment of this invention, viewed from the axial direction. [Figure 2] Cross-sectional view along line II-II in Figure 1 [Figure 3] Figure 1 shows the outer ring, in its standalone state before the insulating resin layer is formed, viewed from the axial direction. [Figure 4] Cross-sectional view along line IV-IV in Figure 3 [Figure 5] Figure 4 shows a modified example of the outer ring of Figure 3, in which the offset direction of the eccentric groove formed on one side of the width face is misaligned with the offset direction of the eccentric groove formed on the other side of the width face. [Figure 6] This diagram shows an eccentric groove formed by chucking the outer ring on a lathe with its outer circumference offset from the rotation center of the lathe's spindle, and then machining a circumferential groove on the width surface. [Figure 7] Figure 3 shows the outer ring of a rolling bearing in the second embodiment of this invention. [Figure 8] Cross-sectional view along line VIII-VIII in Figure 7 [Modes for carrying out the invention]

[0037] [First Embodiment] Figure 1 shows a rolling bearing according to a first embodiment of the present invention. This rolling bearing is used to support the rotating shaft of an electric motor for driving an electric vehicle, etc. This rolling bearing is a so-called insulated rolling bearing. This rolling bearing has an outer ring 1, an inner ring 2 arranged radially inward of the outer ring 1, a plurality of rolling elements 3 incorporated between the outer ring 1 and the inner ring 2, a cage 4, and an insulating resin layer 5 formed on the outer ring 1. In this case, the rolling elements 3 are balls.

[0038] Here, the direction along the bearing's central axis is called the axial direction, the direction perpendicular to the bearing's central axis is called the radial direction, and the direction along the circumference around the bearing's central axis is called the circumferential direction.

[0039] As shown in Figure 2, outer ring width surfaces 6 are formed on both axial sides of the outer ring 1. The outer ring width surfaces 6 are surfaces perpendicular to the axial direction. An outer ring raceway groove 7 is formed on the inner circumference of the outer ring 1 on which the balls 3 roll. The outer ring raceway groove 7 is an arc groove with a concave arc cross-section along the surface of the balls 3, and is formed extending circumferentially from the axial center of the inner surface of the outer ring 1. The outer surface of the outer ring 1 is a cylindrical surface that has not been machined with grooves.

[0040] Inner ring width surfaces 8 are formed on both axial sides of the inner ring 2. The inner ring width surfaces 8 are surfaces perpendicular to the axial direction. An inner ring raceway groove 9 is formed on the outer circumference of the inner ring 2, on which the balls 3 roll. The inner ring raceway groove 9 is an arc groove with a concave arc cross-section along the surface of the balls 3, and is formed extending circumferentially from the axial center of the outer circumference surface of the inner ring 2. The outer ring 1, inner ring 2, and balls 3 are all made of metal (for example, high- and medium-carbon alloy steel, carburized steel, bearing steel, etc.).

[0041] As shown in Figure 1, the retainer 4 is a crown-shaped retainer formed of an annular portion 10 and claw portions 11 that protrude axially from the annular portion 10. Between adjacent claw portions 11 in the circumferential direction, hemispherical pockets 12 (see Figure 2) for accommodating the balls 3 are formed. The retainer 4 holds the balls 3 at regular intervals in the circumferential direction. The retainer 4 is made of resin.

[0042] As shown in Figures 2 and 3, the outer ring width surface 6 is provided with an anti-rotation groove 13 into which the resin forming the insulating resin layer 5 enters. As shown in Figure 3, the anti-rotation groove 13 in this embodiment is formed to extend in a circular shape that is not concentric with the outer circumference circle that forms the outline of the outer circumference of the outer ring 1 in an axial view. The center line of this anti-rotation groove 13 is located at a position radially offset from the center line of the outer circumference of the outer ring 1, and extends in a perfect circle. Hereinafter, the anti-rotation groove 13 in this embodiment will be referred to as the eccentric groove 13a. The eccentric groove 13a is formed to fit within the outer ring width surface 6. In other words, the entire circumference of the eccentric groove 13a is formed on the outer ring width surface 6 without interruption. The distance s radially offset from the center line of the outer circumference of the outer ring 1 by the center line of the eccentric groove 13a is set to 0.1 mm or more (preferably 0.3 mm or more).

[0043] As shown in Figure 2, the eccentric groove 13a is formed in a rectangular cross-section. The depth h of the eccentric groove 13a is set to 0.5 mm or more (preferably 0.7 mm or more). The eccentric groove 13a is formed on both axial outer ring width surfaces 6. As shown in Figure 4, the offset direction of the eccentric groove 13a formed on one side (left in the figure) of the outer ring width surfaces 6 and the offset direction of the eccentric groove 13a formed on the other side (right in the figure) of the outer ring width surface 6 may coincide, or they may not coincide, as shown in Figure 5. In this case, when machining the eccentric groove 13a on the other side (right in the figure) of the outer ring width surface 6 after machining the eccentric groove 13a on one side (left in the figure), it is not necessary to perform circumferential alignment, and the chucking work during machining is not time-consuming.

[0044] Here, as shown in Figure 5, the offset direction of the eccentric groove 13a formed on one side (left in the figure) of the outer ring width surface 6 on both sides of the outer ring width surface 6 in the axial direction may be shifted by 175 to 185° from the offset direction of the eccentric groove 13a formed on the other side (right in the figure). In this case, the rotational force applied to the insulating resin layer 5 (see Figure 2) can be evenly distributed in the circumferential direction.

[0045] As shown in Figure 2, the insulating resin layer 5 has an outer peripheral insulating portion 14 that covers the outer peripheral surface of the outer ring 1 and a width surface insulating portion 15 that covers the width surfaces 6 of the outer ring on both sides. The outer peripheral insulating portion 14 covers the entire outer peripheral surface of the outer ring 1. The outer peripheral surface of the outer peripheral insulating portion 14 is a cylindrical surface with a constant outer diameter. The width surface insulating portion 15 is formed extending radially inward from the radial outer end of the width surface 6 of the outer ring. The width surface insulating portion 15 extends to the radial inner end of the width surface 6 of the outer ring, covering the entire width surface 6 of the outer ring. Here, the outer peripheral insulating portion 14 and the width surface insulating portion 15 are formed integrally. The connection between the outer peripheral insulating portion 14 and the width surface insulating portion 15 has a smoothly connected R-chamfered shape.

[0046] The width surface insulating portion 15 has a protrusion 16 that fits into the eccentric groove 13a. The protrusion 16 is formed when the resin that forms the insulating resin layer 5 enters the eccentric groove 13a. The shape of the protrusion 16 corresponds to the shape of the eccentric groove 13a.

[0047] The insulating resin layer 5 is formed of an insulating resin. The resin can be polyphenylene sulfide resin (PPS), polyphthalamide resin (PPA), or other similar resins. Furthermore, the insulating resin layer 5 can be made with added fiber reinforcement (such as glass fibers or aramid fibers, which have insulating properties).

[0048] The outer ring 1 is manufactured as follows. First, an annular outer ring material is formed by forging metal. Next, an outer ring raceway groove 7 extending in the circumferential direction is formed in the axial center of the inner circumferential surface of the outer ring material by turning. After that, as shown in Figure 6, an eccentric chucking process is performed in which the outer circumferential surface of the outer ring 1 is chucked in an eccentric state from the rotation center of the lathe 17. After the eccentric chucking process, a turning process is performed in which an eccentric groove 13a is formed by turning a circumferential groove on the outer ring width surface 6 using the lathe 17.

[0049] Subsequently, in order to perform the same machining on the opposite outer ring width surface 6, the outer ring 1 is removed from the lathe 17, the outer ring 1 is turned to the opposite side, and the above-described eccentric chuck process is performed. At this time, the eccentric direction of the first machined eccentric groove 13a and the eccentric direction of the next machined eccentric groove 13a on the opposite side do not necessarily have to match, and there is no need to be concerned with the direction when chucking. After the eccentric chuck process, the above-described lathe machining process is performed. As a result, as shown in Figure 5, an outer ring 1 is obtained with eccentric grooves 13a formed on both outer ring width surfaces 6.

[0050] As described above, when manufacturing the outer ring 1, as shown in Figure 6, the outer ring 1 is chucked in the lathe 17 in an eccentric state, and the eccentric groove 13a can then be formed by machining the circumferential groove with the lathe 17, making the machining of the eccentric groove 13a easy.

[0051] Furthermore, as shown in Figure 2, the insulating resin layer 5 is formed by insert molding. That is, an outer ring 1 with an eccentric groove 13a is set inside a mold, and molten resin is injected into the inside of the mold to form the insulating resin layer 5 on the surface of the outer ring 1. By providing this insulating resin layer 5, the current path to the inside of the bearing is blocked, preventing sparks from occurring between the inner surface of the outer ring raceway groove 7 and the surface of the ball 3, and between the inner surface of the inner ring raceway groove 9 and the surface of the ball 3.

[0052] In this embodiment of the rolling bearing, as shown in Figure 2, an anti-rotation groove 13 is formed on the outer ring width surface 6 on which the insulating resin layer 5 is formed. The resin forming the insulating resin layer 5 enters the anti-rotation groove 13, preventing the insulating resin layer 5 from peeling off the outer ring width surface 6. Furthermore, since the anti-rotation groove 13 extends in a circular shape that is not concentric with the outer circumference of the outer ring 1, the relative rotation of the insulating resin layer 5 with respect to the outer ring 1 can be restricted, and creep of the insulating resin layer 5 can be reliably prevented. In addition, by providing this anti-rotation groove 13, there is no need to add another groove (for example, a groove on the outer circumference of the outer ring 1) to increase the adhesion force of the insulating resin layer 5, thus reducing processing costs.

[0053] Furthermore, this rolling bearing employs an eccentric groove 13a as an anti-rotation groove 13. Since the eccentric groove 13a has a perfectly circular shape, it is easy to machine.

[0054] Furthermore, in this rolling bearing, if, for example, the center line of the eccentric groove 13a is significantly offset from the center line of the outer circumference of the outer ring 1, the eccentric groove 13a becomes a circular shape that is interrupted midway on the outer ring width surface 6. In this case, when machining the eccentric groove 13a, the cutting tool may vibrate at the interrupted portion that is at the end of the outer ring width surface 6, making machining difficult. In this configuration, as shown in Figure 3, the entire circumference of the eccentric groove 13a is formed on the outer ring width surface 6, making machining easy.

[0055] Furthermore, as shown in Figure 2, since the eccentric grooves 13a are formed on the outer ring width surface 6 on both axial sides of this rolling bearing, the rotational force applied to the portion of the insulating resin layer 5 that enters the eccentric grooves 13a can be distributed on both axial sides, making the insulating resin layer 5 less susceptible to damage.

[0056] Furthermore, since the offset distance s (see Figure 3) of the eccentric groove 13a in this rolling bearing is sufficiently large, the anti-rotation effect is high, and creep of the insulating resin layer 5 can be prevented more reliably.

[0057] Furthermore, since the side surface of the anti-rotation groove 13 is perpendicular to the direction of rotation, this rolling bearing is particularly effective in preventing the insulating resin layer 5 from lifting and peeling off axially along the tapered shape due to rotational force, compared to, for example, the case where the anti-rotation groove 13 is formed in a tapered shape so that the opening widens.

[0058] Furthermore, because the anti-rotation groove 13 of this rolling bearing is sufficiently deep, there is a large area where the resin of the insulating resin layer 5 is in close contact with the anti-rotation groove 13, making it particularly effective in preventing the insulating resin layer 5 from peeling off.

[0059] Here, multiple eccentric grooves 13a with different offset directions and diameters may be formed on the outer ring width surface 6. For example, two eccentric grooves 13a may be formed on one side (the left side in the figure) of the outer ring width surface 6. When multiple eccentric grooves 13a are formed, the rotational force applied to the portion of the insulating resin layer 5 that has entered the eccentric grooves 13a can be dispersed, making those portions less susceptible to damage. In addition, grooves into which the resin of the insulating resin layer 5 can enter may be formed on the outer circumference of the outer ring 1. This can more effectively prevent the insulating resin layer 5 from peeling off.

[0060] [Second Embodiment] Figures 7 and 8 show a rolling bearing according to a second embodiment of the present invention. The second embodiment differs from the first embodiment only in that the anti-rotation groove 13 is an elliptical groove 13b, which will be described later, instead of an eccentric groove 13a; all other configurations are the same. Therefore, the parts corresponding to the first embodiment are given the same reference numerals and their description is omitted.

[0061] As shown in Figure 7, this anti-rotation groove 13 is an elliptical groove. Hereinafter, the anti-rotation groove 13 in this embodiment will be referred to as the elliptical groove 13b. The elliptical groove 13b is formed to fit within the outer ring width surface 6. In other words, the entire circumference of the elliptical groove 13b is formed on the outer ring width surface 6 without interruption. The length of the major axis of the elliptical groove 13b is set to be 1.01 to 1.20 times (preferably 1.01 to 1.10 times) the length of the minor axis.

[0062] As shown in Figure 8, the elliptical groove 13b is formed with a rectangular cross-section. The depth h of the elliptical groove 13b is 0.5 mm or more (preferably 0.7 mm or more). The elliptical groove 13b is formed on both axial sides of the outer ring width surface 6. Of the outer ring width surfaces 6 on both axial sides, the major axis direction of the elliptical groove 13b formed on one side (left in the figure) and the major axis direction of the elliptical groove 13b formed on the other side (right in the figure) are offset in the circumferential direction. In this embodiment, they are offset in the circumferential direction by a range of 85° to 95° from each other.

[0063] In this rolling bearing, the anti-rotation groove 13 is elliptical in shape, and the relative rotation of the insulating resin layer 5 (see Figure 2) with respect to the outer ring 1 (see Figure 2) is restricted by the pair of arc portions that overlap the major axis of the ellipse, thus providing a high anti-rotation effect and reliably preventing creep of the insulating resin layer 5 (see Figure 2).

[0064] Furthermore, in this rolling bearing, if, for example, the length of the major axis of the elliptical groove 13b is greater than the outer diameter of the outer ring 1, the elliptical groove 13b will be interrupted midway on the outer ring width surface 6. In this case, when machining the elliptical groove 13b, the cutting tool may vibrate at the interrupted portion that is on the end of the outer ring width surface 6, making machining difficult. In this configuration, the entire circumference of the elliptical groove 13b is formed on the outer ring width surface 6, making machining easy.

[0065] Furthermore, since the elliptical grooves 13b are formed on the outer ring width surface 6 on both axial sides of this rolling bearing, the rotational force applied to the portion of the insulating resin layer 5 (see Figure 2) that fits into the elliptical grooves 13b can be distributed to both axial sides.

[0066] Furthermore, since the elliptical groove 13b formed on the outer ring width surface 6 on one side (left in the figure) and the elliptical groove 13b formed on the outer ring width surface 6 on the other side (right in the figure) are arranged to be perpendicular to each other, the rotational force applied to the insulating resin layer 5 (see Figure 2) can be evenly distributed in the circumferential direction.

[0067] In the above embodiment, as shown in Figure 2, the case in which the insulating resin layer 5 is formed on the outer ring 1 and the outer ring width surface 6 was described, but it may also be formed on the inner ring 2 and the inner ring width surface 8. That is, a rotation-preventing groove 13 into which the resin forming the insulating resin layer 5 enters may be provided on the inner ring width surface 8, and the insulating resin layer 5 may be formed so as to cover the entire inner circumferential surface of the inner ring 2 and the inner ring width surface 8. Furthermore, the insulating resin layer 5 may be formed on the inner ring 2 and the inner ring width surface 8 at the same time as it is formed on the outer ring 1 and the outer ring width surface 6.

[0068] In the manufacturing method for providing an eccentric groove 13a on the inner ring width surface 8, the outer circumferential surface of the inner ring 2 is chucked in the lathe 17 (see Figure 6) with the outer circumferential surface offset from the rotation center of the spindle of the lathe 17, and the eccentric groove 13a is machined by machining a circumferential groove on the inner ring width surface 8 with the lathe 17 in that state. Furthermore, although the above embodiments have described ball bearings in which the rolling elements 3 are balls, this invention can also be applied to roller bearings in which the rolling elements 3 are rollers.

[0069] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0070] 1 Outer ring 2 Inner ring 3 Rolling element 5. Insulating resin layer 6,8 Width 13 Anti-rotation groove 13a Eccentric groove 13b Elliptical groove 17 Lathe h depth s offset distance

Claims

1. Outer ring (1) and, An inner ring (2) is positioned radially inward of the outer ring (1), A plurality of rolling elements (3) are incorporated between the outer ring (1) and the inner ring (2), A rolling bearing having an insulating resin layer (5) formed on the outer circumferential surface of the outer ring (1) and the width surfaces (6) on both sides in the axial direction, or on the inner circumferential surface of the inner ring (2) and the width surfaces (8) on both sides in the axial direction, On the width surfaces (6, 8) on which the insulating resin layer (5) is formed, anti-rotation grooves (13) are formed that extend in a circular shape, non-concentric with the outer circumference circle that forms the outline of the outer circumference of the outer ring (1) in an axial view. The rolling bearing is characterized in that the insulating resin layer (5) prevents relative rotation with respect to the outer ring (1) or the inner ring (2) by having the resin forming the insulating resin layer (5) enter the anti-rotation groove (13).

2. The rolling bearing according to claim 1, wherein the anti-rotation groove (13) is an eccentric groove (13a) that extends in a circular shape and whose center line is radially offset from the center line of the outer circumference of the outer ring (1).

3. The rolling bearing according to claim 2, wherein the eccentric groove (13a) is formed to fit within the width surface (6, 8).

4. The rolling bearing according to claim 2 or 3, wherein the eccentric groove (13a) is formed on the width surfaces (6, 8) on both axial sides.

5. The rolling bearing according to claim 2 or 3, wherein the offset distance (s) of the center line of the eccentric groove (13a) is 0.1 mm or more.

6. The rolling bearing according to claim 1, wherein the anti-rotation groove (13) is an elliptical groove (13b).

7. The rolling bearing according to claim 6, wherein the elliptical groove (13b) is formed to fit within the width surface (6, 8).

8. The rolling bearing according to claim 6 or 7, wherein the elliptical groove (13b) is formed on the width surfaces (6, 8) on both axial sides.

9. The rolling bearing according to claim 8, wherein, of the width surfaces (6, 8) on both sides in the axial direction in which the elliptical groove (13b) is formed, the angle between the major axis direction of the elliptical groove (13b) on one of the width surfaces (6, 8) and the major axis direction of the elliptical groove (13b) on the other width surface (6, 8) is 85° or more and 95° or less.

10. The rolling bearing according to claim 1, wherein the anti-rotation groove (13) is formed in a rectangular cross-section.

11. The rolling bearing according to claim 1, wherein the depth (h) of the anti-rotation groove (13) is 0.5 mm or more.

12. Outer ring (1) and, An inner ring (2) is positioned radially inward of the outer ring (1), A plurality of rolling elements (3) are incorporated between the outer ring (1) and the inner ring (2), The outer ring (1) has an insulating resin layer (5) formed on its outer circumferential surface and the width surfaces (6) on both sides in the axial direction, or on the inner circumferential surface and the width surfaces (8) on both sides in the axial direction. On the width surfaces (6, 8) on which the insulating resin layer (5) is formed, anti-rotation grooves (13) are formed that extend in a circular shape, non-concentric with the outer circumference circle that forms the outline of the outer circumference of the outer ring (1) in an axial view. The insulating resin layer (5) prevents relative rotation with respect to the outer ring (1) or the inner ring (2) by having the resin forming the insulating resin layer (5) enter the anti-rotation groove (13). The anti-rotation groove (13) is an eccentric groove (13a) that extends in a circular shape, and the center line of the anti-rotation groove (13) is offset radially from the center line of the outer circumference of the outer ring (1). An eccentric chuck step is performed in which the circumferential surface of the outer ring (1) or the circumferential surface of the inner ring (2), on which the insulating resin layer (5) is formed, is chucked to the lathe (17) while being eccentric from the rotation center of the spindle of the lathe (17), A method for manufacturing a rolling bearing, comprising: a turning step after the eccentric chuck step, a turning step in which a circumferential groove is machined on the width surface (6, 8) using the turning machine (17) to form the eccentric groove (13a).

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