Insulation rolling bearing

Abstract

To provide an insulation rolling bearing which can prevent a mold resin from being lifted from an inner surface of a mold recessed part by molding shrinkage of a resin.SOLUTION: A mold resin 5 has: an outer periphery insulation part 5a which convers an outer periphery of an outer ring 1; an end surface insulation part 5b which covers an axial end surface 6 of the outer ring 1; and an end inner periphery insulation part 5c extending from a radial inner end of the end surface insulation part 5b to the axial inner side and entering a mold recessed part 8. A portion, which is covered with the end inner periphery insulation part 5c, of a recessed part side surface 13 of the mold recessed part 8 is formed as an inclined surface having an inclination which inclines in an axial outward direction toward the radial inner side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to an insulating rolling bearing.

Background Art

[0002] In rolling bearings that support the rotating shaft of an electric motor for driving an electric vehicle, or in rolling bearings that support the rotating shaft of an e-Axle in which an electric motor, an inverter, and a speed reducer for driving an electric vehicle are integrated, when an electric current flows inside the bearing, a spark may occur between the outer ring or the inner ring and the rolling elements, and due to this spark, a phenomenon (electrical erosion) may occur in which the surfaces of the outer ring, inner ring, and rolling elements are locally melted.

[0003] As a rolling bearing capable of preventing this electrical erosion, an insulating rolling bearing in which the surfaces of the outer ring and the inner ring are covered with a molded resin is known (for example, Patent Document 1).

[0004] The insulating rolling bearing of Patent Document 1 includes an outer ring, an inner ring disposed radially inward of the outer ring, a plurality of rolling elements incorporated between the outer ring and the inner ring, an outer ring side molded resin that covers the outer periphery of the outer ring and the axial end faces on both sides of the outer ring, and an inner ring side molded resin that covers the inner periphery of the inner ring and the axial end faces on both sides of the inner ring.

[0005] The outer ring side molded resin is formed by insert molding of the resin. That is, the outer ring is set in a mold, the mold is closed, and the resin is injection molded, so that the molded resin is formed on the surface of the outer ring. Similarly, the inner ring side molded resin is also formed by insert molding of the resin.

[0006] Here, the outer ring side molded resin is formed so as to cover not only the outer periphery and the axial end faces of the outer ring but also the inner periphery of the end portion of the outer ring. That is, annular mold recesses that open to the axial end faces of the outer ring and extend in the circumferential direction are formed at both axial ends of the inner periphery of the outer ring, and the molded resin on the surface of the outer ring is formed so that the resin enters the mold recesses.

[0007] Similarly, the molded resin on the inner ring side is formed so as to cover not only the inner circumference of the inner ring and the axial end faces of the inner ring but also the outer circumference of the end portion of the inner ring. That is, annular mold recesses that open to the axial end faces of the inner ring and extend in the circumferential direction are formed at both axial ends of the outer circumference of the inner ring, and the molded resin on the surface of the inner ring is formed so that resin enters into the mold recesses.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] By the way, when forming the molded resin on the surface of the outer ring, during cooling after insert molding, the molded resin shrinks due to molding shrinkage, and the outer ring also shrinks as the temperature decreases. At this time, since the amount of dimensional change due to the molding shrinkage of the molded resin is larger than the amount of dimensional change accompanying the temperature decrease of the outer ring, there is a possibility that the portion of the molded resin that has entered the mold recesses at both axial ends of the inner circumference of the outer ring may lift off from the inner surface of the mold recesses.

[0010] For example, assume a comparative example shown in FIG. 7. In this comparative example, the molded resin 31 on the surface of the outer ring 30 has an outer peripheral insulating portion 32 that covers the outer circumference of the outer ring 30, an end face insulating portion 34 that covers the axial end faces 33 on both sides of the outer ring 30, and an end portion inner peripheral insulating portion 36 that extends axially inward from the radially inner end of the end face insulating portion 34 and enters into the mold recess 35.

[0011] Here, as shown in FIGS. 8 and 9, the concave surface 37 of the mold recess 35 facing the outer side in the axial direction is usually, for ease of machining, an inclined surface having an inclination that displaces inward in the radial direction (downward in the figure) and inward in the axial direction (leftward in the figure), or a plane perpendicular to the axial direction. This is common (FIG. 8 shows an example of the former, and FIG. 9 shows an example of the latter). That is, it is common for the angle θ formed by the concave surface 37 of the mold recess 35 facing the outer side in the axial direction with respect to the axial direction to be 90° or more (the angle θ shown in FIG. 8 is greater than 90°, and the angle θ shown in FIG. 9 is 90°).

[0012] When this mold resin 31 is formed by insert molding, during cooling after insert molding, the mold resin 31 undergoes molding shrinkage, and the outer ring 30 also shrinks in response to the temperature drop. At this time, the amount of dimensional change due to the molding shrinkage of the mold resin 31 is larger than the amount of dimensional change accompanying the temperature drop of the outer ring 30. Also, as shown in FIGS. 8 and 9, since the corner 38 where the axial end surface 33 of the outer ring 30 intersects the inner surface of the mold recess 35 restricts the movement of the mold resin 31, at the connection portion between the inner peripheral insulating portion 36 and the end surface insulating portion 34 of the end portion of the mold resin 31, as shown by the arrows in FIGS. 8 and 9, resin movement occurs such that the amount of resin movement increases as it moves away from the corner 38. As a result, as shown by the chain line in the figure, the inner peripheral insulating portion 36 at the end of the mold resin 31 deforms so as to bend inward in the radial direction around the connection portion between the inner peripheral insulating portion 36 and the end surface insulating portion 34, and there is a risk of lifting off from the inner surface of the mold recess 35.

[0013] As shown by the chain line in FIGS. 8 and 9, when the inner peripheral insulating portion 36 at the end of the mold resin 31 lifts off from the inner surface of the mold recess 35, a gap is generated between the inner peripheral insulating portion 36 at the end of the mold resin 31 and the inner surface of the mold recess 35. Therefore, a lubricant intrudes into the gap, and creep of the mold resin 31 (circumferential movement of the mold resin 31 with respect to the outer ring 30) is likely to occur.

[0014] Similarly, with respect to the molded resin on the inner ring side, since the amount of dimensional change due to the molding shrinkage of the molded resin is larger than the amount of dimensional change associated with the temperature drop of the inner ring, there was a risk that the portions of the molded resin that entered the mold recesses at both axial ends of the outer periphery of the inner ring would lift off from the inner surface of the mold recesses.

[0015] The problem to be solved by this invention is to provide a rolling bearing with insulation that can prevent the molded resin from lifting off from the inner surface of the mold recess due to the molding shrinkage of the resin.

Means for Solving the Problem

[0016] To solve the above problems, this invention provides a rolling bearing with insulation having the following configuration. [Configuration 1] An outer ring, An inner ring disposed radially inward of the outer ring, A plurality of rolling elements incorporated between the outer ring and the inner ring, And an insulating molded resin that covers the outer periphery of the outer ring and the axial end faces on both sides of the outer ring, Annular mold recesses that open to the axial end faces of the outer ring and extend in the circumferential direction are formed at both axial ends of the inner periphery of the outer ring. In the rolling bearing with insulation, the molded resin has an outer peripheral insulating portion that covers the outer periphery of the outer ring, an end face insulating portion that covers the axial end faces of the outer ring, and an end portion inner peripheral insulating portion that extends axially inward from the radially inner end of the end face insulating portion and enters the mold recess. At least a part of the concave portion side face facing the axial outer side of the mold recess is covered by the end portion inner peripheral insulating portion. The rolling bearing with insulation is characterized in that the portion of the concave portion side face covered by the end portion inner peripheral insulating portion has an inclined surface with an inclination that is displaced axially inward toward the radially outer side.

[0017] When this configuration is adopted, the portion of the concave side surface of the mold recess covered by the inner peripheral insulating portion of the end of the mold resin has an inclination of displacing axially outward in the radially inward direction. Therefore, as the inner peripheral insulating portion of the end of the mold resin moves radially inward, an axial tightening margin will occur between the inner peripheral insulating portion of the end of the mold resin and the concave side surface of the mold recess. For this reason, the inner peripheral insulating portion of the end of the mold resin is less likely to deform so as to bend radially inward around the connection portion between the inner peripheral insulating portion of the end and the end face insulating portion, and it becomes possible to prevent the inner peripheral insulating portion of the end of the mold resin from lifting off from the inner surface of the mold recess due to the molding shrinkage of the resin.

[0018] [Configuration 2] The insulating rolling bearing according to Configuration 1, wherein the inclined surface is an annular conical table surface forming an angle of 87° or less with respect to the axial direction.

[0019] When this configuration is adopted, it becomes possible to surely prevent the inner peripheral insulating portion of the end of the mold resin from deforming so as to bend radially inward around the connection portion between the inner peripheral insulating portion of the end and the end face insulating portion.

[0020] [Configuration 3] The concave side surface has a molded portion covered by the inner peripheral insulating portion of the end and a non-molded portion where the surface of the outer ring is exposed without being covered by the inner peripheral insulating portion of the end. The insulating rolling bearing according to Configuration 1 or 2, wherein the radial height dimension of the non-molded portion is set to 1.0 mm or more.

[0021] When this configuration is adopted, since a non-molded portion having a radial height dimension of 1.0 mm or more is provided on the concave side surface facing the axially outer side of the mold recess, when the outer ring is fixed inside the mold and insert molding of the resin is performed, the outer ring can be fixed by bringing the non-molded portion into contact with the mold. Therefore, the fixing of the outer ring to the mold is stabilized, and it becomes possible to prevent burrs from occurring in the mold resin.

[0022] [Configuration 4] The insulating rolling bearing according to Configuration 3, wherein the non-molded portion is an annular plane perpendicular to the axial direction.

[0023] When this configuration is adopted, since the non-molded portion is an annular plane perpendicular to the axial direction, it becomes easier to manage the dimensional accuracy of the portion of the insert molding die that the non-molded portion contacts, and it is possible to particularly effectively stabilize the fixing of the outer ring to the die.

[0024] [Configuration 5] The insulating rolling bearing according to any one of Configurations 1 to 4, wherein the axial distance from the side surface of the concave portion to the surface of the end face insulating portion is set to 2.25 mm or more.

[0025] When this configuration is adopted, since the axial distance from the side surface of the concave portion of the mold concave portion of the outer ring to the surface of the end face insulating portion of the mold resin is 2.25 mm or more, when the bearing is assembled by bringing the mold resin on the outer ring side into contact with the axially abutting surface on the inner circumference of the housing, the creepage distance from the abutting surface to the outer ring can be ensured, and it is possible to effectively prevent electrolytic corrosion.

[0026] [Configuration 6] The insulating rolling bearing according to any one of Configurations 1 to 5, wherein a stealing groove extending in the circumferential direction with a cross-sectional shape recessed radially outward is formed on the bottom surface of the concave portion facing the radially inner side of the mold concave portion.

[0027] When this configuration is adopted, since a stealing groove extending in the circumferential direction with a cross-sectional shape recessed radially outward is formed on the bottom surface of the concave portion of the mold concave portion, the axial outward movement of the inner peripheral insulating portion at the end of the mold resin is restricted by the fitting between the inner peripheral insulating portion at the end of the mold resin and the stealing groove of the mold concave portion, and the inner peripheral insulating portion at the end of the mold resin is less likely to separate from the side surface of the concave portion of the mold concave portion. Therefore, it is possible to particularly effectively prevent the inner peripheral insulating portion at the end of the mold resin from lifting off from the inner surface of the mold concave portion due to the inclination of the side surface of the concave portion of the mold concave portion.

[0028] [Configuration 7] The outer ring, an inner ring disposed radially inward of the outer ring; a plurality of rolling elements incorporated between the outer ring and the inner ring; and an insulating molded resin covering the inner circumference of the inner ring and the axial end faces on both sides of the inner ring, annular mold recesses that are open to the axial end faces of the inner ring and extend in the circumferential direction are formed at both axial ends of the outer circumference of the inner ring, in the insulating rolling bearing, the molded resin has an inner circumferential insulating portion covering the inner circumference of the inner ring, an end face insulating portion covering the axial end faces of the inner ring, and an end portion outer circumferential insulating portion extending axially inward from the radially outer end of the end face insulating portion and entering the mold recess, and at least a part of the recess side face facing axially outward of the mold recess is covered by the end portion outer circumferential insulating portion, an insulating rolling bearing, wherein a portion of the recess side face covered by the end portion outer circumferential insulating portion of the molded resin is an inclined surface having an inclination that is displaced axially outward toward the radially outer side.

[0029] With this configuration, since a portion of the recess side face of the mold recess covered by the end portion outer circumferential insulating portion of the molded resin has an inclination that is displaced axially outward toward the radially outer side, an axial tightening margin is generated between the end portion outer circumferential insulating portion of the molded resin and the recess side face of the mold recess as the end portion outer circumferential insulating portion of the molded resin moves radially outward. Therefore, the end portion outer circumferential insulating portion of the molded resin is less likely to be deformed so as to bend radially outward around the connection portion between the end portion outer circumferential insulating portion and the end face insulating portion, and it is possible to prevent the end portion outer circumferential insulating portion of the molded resin from lifting off from the inner surface of the mold recess due to the molding shrinkage of the resin.

[0030] [Configuration 8] The insulating rolling bearing according to Configuration 7, wherein the inclined surface is an annular frustum surface having an angle of 87° or less with respect to the axial direction.

[0031] With this configuration, it is possible to reliably prevent the end portion outer circumferential insulating portion of the molded resin from being deformed so as to bend radially outward around the connection portion between the end portion outer circumferential insulating portion and the end face insulating portion.

[0032] [Configuration 9] The concave side surface has a molded portion covered by the end outer peripheral insulating portion and a non-molded portion where the surface of the inner ring is exposed without being covered by the end outer peripheral insulating portion. The insulating rolling bearing according to Configuration 7 or 8, wherein the radial height dimension of the non-molded portion is set to 1.0 mm or more.

[0033] When this configuration is adopted, since a non-molded portion having a radial height dimension of 1.0 mm or more is provided on the concave side surface facing the outer side in the axial direction of the molded recess, when the inner ring is fixed inside the mold and resin insert molding is performed, the inner ring can be fixed by bringing the non-molded portion into contact with the mold. Therefore, the fixing of the inner ring to the mold is stabilized, and it is possible to prevent burrs from occurring in the molded resin.

[0034] [Configuration 10] The insulating rolling bearing according to Configuration 9, wherein the non-molded portion is an annular plane perpendicular to the axial direction.

[0035] When this configuration is adopted, since the non-molded portion is an annular plane perpendicular to the axial direction, it becomes easier to manage the dimensional accuracy of the portion of the insert molding mold with which the non-molded portion comes into contact, and it is possible to stably fix the inner ring to the mold particularly effectively.

[0036] [Configuration 11] The insulating rolling bearing according to any one of Configurations 7 to 10, wherein the axial distance from the concave side surface to the surface of the end face insulating portion is set to 2.25 mm or more.

[0037] When this configuration is adopted, since the axial distance from the concave side surface of the molded recess of the inner ring to the surface of the end face insulating portion of the molded resin is 2.25 mm or more, when the bearing is assembled by bringing the molded resin on the inner ring side into contact with the axial abutting surface on the outer periphery of the shaft inserted into the inner ring, the creepage distance from the abutting surface to the inner ring can be ensured, and it is possible to effectively prevent electric erosion.

[0038] [Constitution 12] The insulating rolling bearing according to any one of Constitutions 7 to 11, wherein a stealing groove extending in the circumferential direction with a cross-sectional shape recessed radially inward is formed on the bottom surface of the recess facing the radially outer side of the mold recess.

[0039] When this constitution is adopted, since a stealing groove extending in the circumferential direction with a cross-sectional shape recessed radially inward is formed on the bottom surface of the mold recess, the movement of the outer peripheral insulating portion at the end of the mold resin axially outward is restricted by the fitting between the outer peripheral insulating portion at the end of the mold resin and the stealing groove of the mold recess, and the outer peripheral insulating portion at the end of the mold resin is difficult to separate from the side surface of the recess of the mold recess. Therefore, it is possible to particularly effectively prevent the outer peripheral insulating portion at the end of the mold resin from rising from the inner surface of the mold recess due to the inclination of the side surface of the recess of the mold recess. [Effect of the Invention]

[0040] The insulating rolling bearing of this invention can prevent the mold resin from rising from the inner surface of the mold recess due to the molding shrinkage of the resin. [Brief Description of the Drawings]

[0041]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0042] FIG. 1 shows a rolling bearing with insulation according to a first embodiment of the present invention. This rolling bearing with insulation has an outer ring 1, an inner ring 2 coaxially arranged radially inside the outer ring 1, a plurality of rolling elements 3 incorporated at intervals in the circumferential direction between the outer ring 1 and the inner ring 2, an annular cage 4 for holding the circumferential intervals of the plurality of rolling elements 3, and a mold resin 5 covering the surface of the outer ring 1. The outer ring 1, the inner ring 2, and the rolling elements 3 are each formed of a steel material.

[0043] The axial direction is the direction parallel to the central axis of the outer ring 1 (the central axis of the bearing), the radial direction is the direction perpendicular to the central axis of the outer ring 1, and the circumferential direction is the direction along the circumference that orbits around the central axis of the outer ring 1. The outer ring 1 and the inner ring 2 are formed symmetrically with respect to the axial center. Axially inward means the direction approaching the axial center of the outer ring 1 and the inner ring 2 along the axial direction, and axially outward means the direction moving away from the axial center of the outer ring 1 and the inner ring 2 along the axial direction.

[0044] The outer circumference of the outer ring 1 is formed in a cylindrical shape. The axial end faces 6 on both sides of the outer ring 1 are formed in an annular planar shape perpendicular to the axial direction. On the inner circumference of the outer ring 1, an outer ring raceway groove 7 in which the rolling elements 3 rollingly contact, a pair of mold recesses 8, and a cylindrical surface 9 with a constant inner diameter connecting between the outer ring raceway groove 7 and the mold recesses 8 are formed. The outer ring raceway groove 7 is formed at the axial center of the inner circumference of the outer ring 1, and the cylindrical surface 9 is formed adjacent to the outer side in the axial direction of the outer ring raceway groove 7. The pair of mold recesses 8 are formed at both axial ends of the inner circumference of the outer ring 1. The mold recess 8 is a recess recessed radially outward with respect to the cylindrical surface 9, and is open to the axial end face 6 of the outer ring 1 and extends in the circumferential direction.

[0045] The inner circumference of the inner ring 2 is formed in a cylindrical shape. The axial end faces 10 on both sides of the inner ring 2 are formed in an annular planar shape perpendicular to the axial direction. On the outer circumference of the inner ring 2, an inner ring raceway groove 11 in which the rolling elements 3 rollingly contact and a cylindrical surface 12 with a constant outer diameter connecting between the inner ring raceway groove 11 and the axial end face 10 of the inner ring 2 are formed. The inner ring raceway groove 11 is formed at the axial center of the outer circumference of the inner ring 2, and the cylindrical surface 12 is formed adjacent to the outside in the axial direction of the inner ring raceway groove 11.

[0046] The rolling elements 3 are radially sandwiched between the outer ring raceway groove 7 and the inner ring raceway groove 11. The rolling elements 3 are balls here. The outer ring raceway groove 7 is an arc groove whose cross-sectional shape perpendicular to the circumferential direction is symmetric with respect to the axial center of the outer ring 1, and the inner ring raceway groove 11 is also an arc groove whose cross-sectional shape perpendicular to the circumferential direction is symmetric with respect to the axial center of the inner ring 2.

[0047] The mold resin 5 is an insulating film that covers the outer circumference of the outer ring 1, the axial end faces 6 on both sides of the outer ring 1, and the inner circumferences of the end portions on both sides of the outer ring 1. The mold resin 5 is formed by insert molding. That is, the outer ring 1 is set inside a mold (not shown), and the molten resin is injected into the mold, so that the mold resin 5 is formed on the surface of the outer ring 1. The mold resin 5 has a radial thickness of 0.8 mm or more (preferably 1.0 mm or more) at the axial center of the outer circumference of the outer ring 1.

[0048] The mold resin 5 is formed of a resin having insulating properties. Specifically, the mold resin 5 is formed of a resin having a dielectric breakdown strength of 1 kV / mm or more. Also, a resin having a comparative surface leakage resistance index (CTI value) of 600 V or more is used for the resin forming the mold resin 5. Here, the comparative surface leakage resistance index means the comparative tracking index (CTI value) obtained by measuring by the method defined in the Japanese Industrial Standard JIS C2134:2007 "Method for Measuring the Assurance and Comparative Tracking Index of Solid Insulating Materials" (a standard corresponding to IEC60112).

[0049] As the resin forming the mold resin 5, a resin obtained by adding a fiber reinforcing material to a resin material is used. As the resin material, for example, polyphenylene sulfide resin (PPS), polyphthalamide resin (PPA), etc. can be used. As the fiber reinforcing material, those having insulating properties such as glass fiber and aramid fiber can be used.

[0050] The mold resin 5 has an outer peripheral insulating portion 5a that covers the outer periphery of the outer ring 1, an end face insulating portion 5b that covers the axial end face 6 of the outer ring 1, and an end inner peripheral insulating portion 5c that extends axially inward from the radially inner end of the end face insulating portion 5b and enters the mold recess 8. Here, the configuration of the end face insulating portion 5b on one axial side (right side in the figure), the mold recess 8, and its vicinity is the same configuration symmetric with respect to the axial center as the configuration of the end face insulating portion 5b on the other axial side (left side in the figure), the mold recess 8, and its vicinity. Therefore, hereinafter, the configuration of the end face insulating portion 5b on one axial side, the mold recess 8, and its vicinity will be described, and the description of the configuration on the other axial side will be omitted.

[0051] As shown in FIG. 2, the mold recess 8 has a recess side surface 13 that is continuous with the axial outer end (right end in the figure) of the cylindrical surface 9 on the inner periphery of the outer ring 1, and a recess bottom surface 14 that is continuous with the radially inner end (lower end in the figure) of the axial end face 6 of the outer ring 1. The recess side surface 13 is a surface facing axially outward (right side in the figure), and the recess bottom surface 14 is a surface facing radially inward (lower side in the figure).

[0052] The end inner peripheral insulating portion 5c of the mold resin 5 is formed so as to cover the radially outer portion of the recess side surface 13 and the entire recess bottom surface 14. The recess side surface 13 has a molded portion 15 covered by the end inner peripheral insulating portion 5c and a non-molded portion 16 where the surface of the steel material constituting the outer ring 1 is exposed without being covered by the end inner peripheral insulating portion 5c. The radial height dimension H of the non-molded portion 16 is set to 1.0 mm or more.

[0053] The concave side surface 13 (molded portion 15 and non-molded portion 16) is an inclined surface having an inclination that displaces radially inward (downward in the figure) and axially outward (right end in the figure). The inclined surface is an annular frustum surface forming an angle θ of 87° or less (preferably 85° or less) with respect to the axial direction. The axial distance W from the non-molded portion 16 of the concave side surface 13 to the surface of the end face insulating portion 5b is set to be 2.25 mm or more. The concave bottom surface 14 is a cylindrical surface having a constant inner diameter along the axial direction.

[0054] The surface (axially outer surface) of the end face insulating portion 5b of the molded resin 5 is formed in a planar shape perpendicular to the axial direction. The inner circumference of the end portion inner circumference insulating portion 5c of the molded resin 5 is formed in a cylindrical shape having a constant inner diameter along the axial direction from the boundary position between the molded portion 15 and the non-molded portion 16 of the concave side surface 13. The inner circumference of the end portion inner circumference insulating portion 5c of the molded resin 5 intersects at a right angle with the surface of the end face insulating portion 5b of the molded resin 5.

[0055] This insulated rolling bearing can be assembled and used in a housing 20 shown by the chain line in FIG. 1. The inner circumference of the housing 20 has a cylindrical inner circumference fitting surface 21 that fits onto the outer circumference insulating portion 5a of the molded resin 5, an axial abutting surface 22 that extends radially inward from the inner circumference fitting surface 21, and an inner circumference cylindrical surface 23 that extends from the radially inner end of the abutting surface 22 to the side opposite to the inner circumference fitting surface 21. The insulated rolling bearing is assembled by bringing the end face insulating portion 5b of the molded resin 5 into contact with the abutting surface 22 on the inner circumference of the housing 20. The inner diameter of the abutting surface 22 of the housing 20 is set to be smaller than the inner diameter of the end portion inner circumference insulating portion 5c of the molded resin 5.

[0056] By the way, when the molded resin 5 shown in Fig. 1 is formed by insert molding, the molded resin 5 shrinks during cooling after insert molding, and the outer ring 1 also shrinks as the temperature decreases. At this time, the amount of dimensional change due to the molding shrinkage of the molded resin 5 is larger than the amount of dimensional change associated with the temperature drop of the outer ring 1. Also, since the corner 17 where the axial end face 6 of the outer ring 1 and the bottom face 14 of the recess intersect as shown in Fig. 2 restricts the movement of the molded resin 5, resin movement occurs at the connection part between the inner peripheral insulating part 5c and the end face insulating part 5b of the end of the molded resin 5 such that the amount of resin movement increases as the distance from the corner 17 increases. As a result, the inner peripheral insulating part 5c at the end of the molded resin 5 may deform so as to bend radially inward around the connection part between the inner peripheral insulating part 5c and the end face insulating part 5b, and due to this deformation, there is a possibility that the inner peripheral insulating part 5c at the end will lift off from the bottom face 14 of the recess.

[0057] When the inner peripheral insulating part 5c at the end of the molded resin 5 lifts off from the bottom face 14 of the recess, a gap is formed between the inner peripheral insulating part 5c at the end of the molded resin 5 and the side face 13 and the bottom face 14 of the recess. As a result, a lubricant may enter this gap, and there is a problem that creep of the molded resin 5 (circumferential movement of the molded resin 5 relative to the outer ring 1) is likely to occur.

[0058] To address this problem, in this insulated rolling bearing, as shown in Fig. 2, the portion of the side face 13 of the recess covered by the inner peripheral insulating part 5c at the end of the molded resin 5 has an inclination to displace axially outward toward the radially inner side. Therefore, as the inner peripheral insulating part 5c at the end of the molded resin 5 moves radially inward, an axial tightening margin is generated between the inner peripheral insulating part 5c at the end of the molded resin 5 and the side face 13 of the recess. For this reason, it is difficult for the inner peripheral insulating part 5c at the end of the molded resin 5 to deform so as to bend radially inward around the connection part between the inner peripheral insulating part 5c and the end face insulating part 5b, and it is possible to prevent the inner peripheral insulating part 5c at the end of the molded resin 5 from lifting off from the inner surface of the mold recess 8 due to the molding shrinkage of the resin.

[0059] Further, in this insulated rolling bearing, the portion of the concave side surface 13 covered by the inner peripheral insulating portion 5c of the end of the mold resin 5 forms an angle θ of 87° or less (preferably 85° or less) with respect to the axial direction. Therefore, it is possible to surely prevent the inner peripheral insulating portion 5c of the end of the mold resin 5 from deforming so as to bend radially inward around the connection portion between the inner peripheral insulating portion 5c and the end face insulating portion 5b.

[0060] Further, in this insulated rolling bearing, a non-molded portion 16 having a radial height dimension H of 1.0 mm or more is provided on the concave side surface 13 facing the outer side in the axial direction of the mold recess 8. Therefore, when the outer ring 1 is fixed inside the mold and insert molding of the resin is performed, the non-molded portion 16 can be brought into contact with the mold to fix the outer ring 1. Therefore, the fixing of the outer ring 1 to the mold is stable, and it is possible to prevent burrs from occurring in the mold resin 5.

[0061] Further, in this insulated rolling bearing, the axial distance W from the concave side surface 13 of the mold recess 8 of the outer ring 1 to the surface of the end face insulating portion 5b of the mold resin 5 is set to 2.25 mm or more. Therefore, as shown by the dashed line in FIG. 1, when the bearing is assembled by bringing the end face insulating portion 5b of the mold resin 5 into contact with the axially abutting surface 22 on the inner periphery of the housing 20, the creepage distance from the abutting surface 22 to the outer ring 1 can be ensured, and it is possible to effectively prevent electric erosion.

[0062] That is, in recent years, the voltage applied to the electric motor for driving an electric vehicle is about 100V. According to the standard EN61984 of the International Electrotechnical Commission (IEC), when the contamination degree is 3 and the Comparative Tracking Index (CTI) value is 100 - 175V, the creepage distance required to ensure electrical insulation when this 100V voltage is applied is 2.25mm or more. Therefore, when this insulating rolling bearing of the present embodiment is used as a rolling bearing that supports the rotating shaft of the electric motor for driving an electric vehicle, or as a rolling bearing that supports the rotating shaft of an e - Axle in which the electric motor, inverter, and speed reducer for driving an electric vehicle are integrated, if the axial distance W from the concave surface 13 of the mold recess 8 of the outer ring 1 to the surface of the end - face insulating portion 5b shown in Fig. 2 is 2.25mm or more, it becomes possible to ensure a creepage distance of 2.25mm or more between the outer ring 1 and the housing 20 shown in Fig. 1, and it becomes possible to effectively prevent electrolytic corrosion.

[0063] Fig. 3 shows a second embodiment of the present invention. The second embodiment differs only in the configuration of the concave surface 13 compared with the first embodiment, and the other configurations are the same. Therefore, the parts corresponding to the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0064] The molded portion 15 of the concave surface 13 is an inclined surface having an inclination that displaces radially inward (downward in the figure) toward the outer side in the axial direction (the right end in the figure). The inclined surface is an annular conical - table surface that forms an angle θ of 87° or less (preferably 85° or less) with respect to the axial direction. On the other hand, the non - molded portion 16 of the concave surface 13 is an annular plane perpendicular to the axial direction. The axial distance W from the non - molded portion 16 of the concave surface 13 to the surface of the end - face insulating portion 5b is set to 2.25mm or more. The concave bottom surface 14 is a cylindrical surface with a constant inner diameter along the axial direction.

[0065] In the insulating rolling bearing of this embodiment, since the non-molded portion 16 of the concave portion side surface 13 is an annular plane perpendicular to the axial direction, the dimensional accuracy of the portion of the insert molding die that contacts the non-molded portion 16 is easy to manage. Therefore, it is possible to stably fix the outer ring 1 to the die particularly effectively. In addition, it has the same operational effects as the first embodiment.

[0066] Fig. 4 shows a third embodiment of the present invention. The third embodiment differs only in the configuration of the concave portion bottom surface 14 compared with the first embodiment, and the other configurations are the same. Therefore, the parts corresponding to the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

[0067] On the concave portion bottom surface 14 of the mold concave portion 8, a thievery groove 18 extending in the circumferential direction with a cross-sectional shape recessed radially outward is formed. That is, the concave portion bottom surface 14 is formed so as to have a portion (thievery groove 18) that is displaced radially outward toward the inner side in the axial direction (left side in the figure) in a cross-section perpendicular to the circumferential direction.

[0068] In the insulating rolling bearing of this embodiment, since a thievery groove 18 extending in the circumferential direction with a cross-sectional shape recessed radially outward is formed on the concave portion bottom surface 14 of the mold concave portion 8, the axial outward movement of the inner peripheral insulating portion 5c at the end of the mold resin 5 is restricted by the fitting between the inner peripheral insulating portion 5c at the end of the mold resin 5 and the thievery groove 18 of the mold concave portion 8, and the inner peripheral insulating portion 5c at the end of the mold resin 5 is unlikely to separate from the concave portion side surface 13 of the mold concave portion 8. Therefore, it is possible to particularly effectively prevent the inner peripheral insulating portion 5c at the end of the mold resin 5 from floating from the inner surface of the mold concave portion 8 due to the inclination of the concave portion side surface 13 of the mold concave portion 8.

[0069] Fig. 5 shows a fourth embodiment of the present invention. The fourth embodiment replaces the configuration of the concave portion side surface 13 of the first embodiment (see Fig. 2) with the configuration of the concave portion side surface 13 of the second embodiment (see Fig. 3), and replaces the configuration of the concave portion bottom surface 14 of the first embodiment (see Fig. 2) with the configuration of the concave portion bottom surface 14 of the third embodiment (see Fig. 4). Therefore, the parts corresponding to the above embodiments are denoted by the same reference numerals and the description thereof is omitted.

[0070] Figure 6 shows the fifth embodiment of the present invention. The fifth embodiment corresponds to reversing the relationship between the outer ring 1 and the inner ring 2 of the first embodiment. Parts corresponding to the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

[0071] On the outer periphery of the inner ring 2, an inner ring raceway groove 11 in which the rolling elements 3 rollingly contact, a pair of mold recesses 8, and a cylindrical surface 12 having a constant outer diameter connecting between the inner ring raceway groove 11 and the mold recesses 8 are formed. The inner ring raceway groove 11 is formed at the axial center of the outer periphery of the inner ring 2, and the cylindrical surface 12 is formed adjacent to the outer side in the axial direction of the inner ring raceway groove 11. The pair of mold recesses 8 are formed at both axial ends of the outer periphery of the inner ring 2. The mold recess 8 is a groove that opens to the axial end surface 10 of the inner ring 2 and extends in the circumferential direction.

[0072] The mold resin 5 is an insulating film that covers the inner periphery of the inner ring 2, the axial end surfaces 10 on both sides of the inner ring 2, and the outer periphery of the ends on both sides of the inner ring 2. The mold resin 5 is formed by insert molding. That is, the inner ring 2 is set inside a mold (not shown), and the molten resin is injected into the mold, so that the mold resin 5 is formed on the surface of the inner ring 2. The mold resin 5 has a radial thickness of 0.8 mm or more (preferably 1.0 mm or more) at the axial center of the inner periphery of the inner ring 2.

[0073] The mold resin 5 has an inner peripheral insulating portion 5d that covers the inner periphery of the inner ring 2, an end surface insulating portion 5e that covers the axial end surface 10 of the inner ring 2, and an end outer peripheral insulating portion 5f that extends inward in the axial direction from the outer radial end of the end surface insulating portion 5e and enters the mold recess 8.

[0074] Here, the mold recess 8, the inner peripheral insulating portion 5d, the end face insulating portion 5e, and the end portion outer peripheral insulating portion 5f respectively correspond to the mold recess 8, the outer peripheral insulating portion 5a, the end face insulating portion 5b, and the end portion inner peripheral insulating portion 5c of the first embodiment (see FIG. 1). That is, the configurations of the mold recess 8, the inner peripheral insulating portion 5d, the end face insulating portion 5e, and the end portion outer peripheral insulating portion 5f shown in FIG. 6 are the same configurations in which the radially outer side and the radially inner side of the mold recess 8, the outer peripheral insulating portion 5a, the end face insulating portion 5b, and the end portion inner peripheral insulating portion 5c of the first embodiment (see FIG. 1) are simply reversed. Further, the fifth embodiment exhibits the same operational effects as the first embodiment.

[0075] The configuration of the mold recess 8 of the second embodiment (see FIG. 3), the third embodiment (see FIG. 4), and the fourth embodiment (see FIG. 5) may be applied to the fifth embodiment (FIG. 6) with the radially outer side and the radially inner side reversed.

[0076] In each of the above embodiments, a ball has been adopted as the rolling element 3 for illustration, but rolling elements 3 having other shapes such as cylindrical rollers may also be adopted.

[0077] It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0078] 1 Outer ring 2 Inner ring 3 Rolling element 5 Mold resin 5a Outer peripheral insulating portion 5b End face insulating portion 5c End portion inner peripheral insulating portion 5d Inner peripheral insulating portion 5e End face insulating portion 5f End portion outer peripheral insulating portion 6 Axial end face 8 Mold recess 10 Axial end face 13 Recess side face 14 Bottom surface of the recess 15 Molded part 16 Non-molded part 18 Pilferage groove Height dimension in the H radial direction W Axial distance θ Angle

Claims

1. An outer ring (1), an inner ring (2) disposed radially inside the outer ring (1), a plurality of rolling elements (3) incorporated between the outer ring (1) and the inner ring (2), and an insulating mold resin (5) covering the outer periphery of the outer ring (1) and the axial end faces (6) on both sides of the outer ring (1), wherein annular mold recesses (8) are formed at both axial ends of the inner periphery of the outer ring (1), opening to the axial end face (6) of the outer ring (1) and extending in the circumferential direction, the mold resin (5) has an outer peripheral insulating portion (5a) covering the outer periphery of the outer ring (1), an end face insulating portion (5b) covering the axial end face (6) of the outer ring (1), and an end inner peripheral insulating portion (5c) extending axially inward from the radially inner end of the end face insulating portion (5b) and entering the mold recess (8), and at least a part of the recess side face (13) facing the axial outside of the mold recess (8) is covered by the end inner peripheral insulating portion (5c). In the insulating rolling bearing, the portion of the recess side face (13) covered by the end inner peripheral insulating portion (5c) is an inclined surface having an inclination that is displaced axially outward toward the radially inner side, and is characterized by the insulating rolling bearing.

2. The insulating rolling bearing according to claim 1, wherein the inclined surface is an annular frustum surface forming an angle (θ) of 87° or less with respect to the axial direction.

3. The recess side face (13) has a molded portion (15) covered by the end inner peripheral insulating portion (5c) and a non-molded portion (16) where the surface of the outer ring (1) is exposed without being covered by the end inner peripheral insulating portion (5c). The insulating rolling bearing according to claim 1 or 2, wherein the radial height dimension (H) of the non-molded portion (16) is set to 1.0 mm or more.

4. The insulating rolling bearing according to claim 3, wherein the non-molded portion (16) is an annular plane perpendicular to the axial direction.

5. The insulating rolling bearing according to claim 1 or 2, wherein the axial distance (W) from the recess side face (13) to the surface of the end face insulating portion (5b) is set to 2.25 mm or more.

6. The insulating rolling bearing according to claim 1 or 2, wherein a stealing groove (18) extending in the circumferential direction with a cross-sectional shape recessed radially outward is formed on the recess bottom face (14) facing the radially inner side of the mold recess (8).

7. An outer ring (1), an inner ring (2) disposed radially inside the outer ring (1), a plurality of rolling elements (3) incorporated between the outer ring (1) and the inner ring (2), It has an insulating mold resin (5) that covers the inner circumference of the inner ring (2) and the axial end faces (10) on both sides of the inner ring (2). An annular mold recess (8) that opens to the axial end face (10) of the inner ring (2) and extends in the circumferential direction is formed at both axial ends of the outer circumference of the inner ring (2). In the insulating rolling bearing, the mold resin (5) has an inner circumferential insulating portion (5d) that covers the inner circumference of the inner ring (2), an end face insulating portion (5e) that covers the axial end face (10) of the inner ring (2), and an end portion outer circumferential insulating portion (5f) that extends axially inward from the radially outer end of the end face insulating portion (5e) and enters the mold recess (8), and at least a part of the recess side face facing the outside in the axial direction of the mold recess (8) is covered by the end portion outer circumferential insulating portion (5f). The insulating rolling bearing is characterized in that a portion of the recess side face covered by the end portion outer circumferential insulating portion (5f) is an inclined surface having an inclination that is displaced axially outward toward the radially outer side.

8. The insulating rolling bearing according to claim 7, wherein the inclined surface is an annular frustum surface forming an angle of 87° or less with respect to the axial direction.

9. The recess side face has a molded portion covered by the end portion outer circumferential insulating portion (5f) and a non-molded portion where the surface of the inner ring (2) is exposed without being covered by the end portion outer circumferential insulating portion (5f). The insulating rolling bearing according to claim 7 or 8, wherein the radial height dimension of the non-molded portion is set to 1.0 mm or more.

10. The insulating rolling bearing according to claim 9, wherein the non-molded portion is an annular plane perpendicular to the axial direction.

11. The insulating rolling bearing according to claim 7 or 8, wherein the axial distance from the recess side face to the surface of the end face insulating portion (5e) is set to 2.25 mm or more.

12. The insulating rolling bearing according to claim 7 or 8, wherein a thieving groove that extends in the circumferential direction with a cross-sectional shape that is recessed radially inward is formed on the recess bottom face facing the outside in the radial direction of the mold recess (8).

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