Insulated rolling bearing

Abstract

The present invention relates to an insulated rolling bearing in which a molded resin (5) has: an outer peripheral insulating part (5a) that covers the outer periphery of an outer ring (1); an end surface insulating portion (5b) covering an axial end surface (6) of the outer ring (1); and an end portion inner peripheral insulating portion (5c) extending axially inward from the radially inner end of the end surface insulating portion (5b) and entering the molded recess (8), the portion of the recess side surface (13) of the molded recess (8) covered by the end portion inner peripheral insulating portion (5c) being formed as an inclined surface having an inclination that is displaced axially outward toward the radially inner side.

Description

Technical Field

[0001] The present invention relates to an insulated rolling bearing. Background Art

[0002] [Background of the First Invention]

[0003] In rolling bearings that support the rotating shaft of an electric motor for driving an electric vehicle, rolling bearings for supporting the rotating shaft of an e-Axle in which an electric motor, an inverter, and a transmission for driving an electric vehicle are integrated, etc., for devices that use electricity, current flows inside the bearing, and as a result, sparks are generated between the outer ring or the inner ring and the rolling elements. Sometimes, local melting (electrical erosion) of the surfaces of the outer ring, inner ring, and rolling elements occurs due to these sparks.

[0004] As a rolling bearing capable of preventing such electrical erosion, an insulated 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).

[0005] The insulated rolling bearing of Patent Document 1 has: an outer ring; an inner ring disposed radially inside the outer ring; a plurality of rolling elements assembled between the outer ring and the inner ring; a molded resin on the outer ring side that covers the outer periphery of the outer ring and the axial end faces on both sides of the outer ring; and a molded resin on the inner ring side that covers the inner periphery of the inner ring and the axial end faces on both sides of the inner ring.

[0006] The molded resin on the outer ring side is formed by insert molding of the resin. That is, the outer ring is placed in a mold, and the mold is closed to inject-mold the resin, whereby a molded resin is formed on the surface of the outer ring. Similarly, the molded resin on the inner ring side is also formed by insert molding of the resin.

[0007] Here, the molded resin on the outer ring side is formed so as to cover not only the outer periphery of the outer ring and the axial end face of the outer ring, but also the inner periphery of the end portion of the outer ring. That is, annular molded recesses that open to the axial end face 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 in such a way that the resin enters into these molded recesses.

[0008] Similarly, the molded resin on the inner ring side is formed so as to cover not only the inner periphery of the inner ring and the axial end face of the inner ring, but also the outer periphery of the end portion of the inner ring. That is, annular molded recesses that open to the axial end face of the inner ring and extend in the circumferential direction are formed at both axial ends of the outer periphery of the inner ring, and the molded resin on the surface of the inner ring is formed in such a way that the resin enters into these molded recesses.

[0009] [Background of the Second Invention]

[0010] In addition, in order to prevent the above-described electrical erosion, an insulated rolling bearing 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 is used (for example, Patent Documents 1 and 2).

[0011] The insulated rolling bearing of Patent Document 1 has: an outer ring; an inner ring disposed radially inside the outer ring; a plurality of balls assembled between the outer ring and the inner ring; an insulating resin layer on the outer ring side, continuously formed on the entire outer peripheral surface of the outer ring, the entire outer ring width surfaces on both axial sides of the outer ring, and a part of the inner peripheral surface of the outer ring; and an insulating resin layer on the inner ring side, continuously formed on the entire inner peripheral surface of the inner ring, the entire inner ring width surfaces on both axial sides of the inner ring, and a part of the outer peripheral surface of the inner ring.

[0012] In the above-mentioned insulated rolling bearing, the insulating resin layer on the outer ring side is formed by insert molding. That is, the outer ring is placed in a mold, and the mold is closed to inject-mold the resin, whereby an insulating resin layer is formed on the outer peripheral surface, the outer ring width surface, and the inner peripheral surface of the outer ring. Similarly, the insulating resin layer on the inner ring side is also formed by insert molding.

[0013] In the insulated rolling bearing of Patent Document 2, an insulating resin layer continuous on a part of the entire outer peripheral surface of the outer ring and the outer ring width surfaces on both axial sides of the outer ring is also formed by insert molding.

[0014] However, when forming the insulating resin layer of the outer ring by injection molding, during cooling after injection molding, the insulating resin layer shrinks during molding, and the outer ring also shrinks due to temperature change. Here, depending on 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 amount of dimensional change caused by the molding shrinkage of the insulating resin layer is greater than the amount of dimensional change of the outer ring accompanying the temperature decrease. Therefore, an axial offset occurs between the insulating resin layer on the outer peripheral surface of the outer ring and the outer peripheral surface of the outer ring, and a radial offset also occurs between the insulating resin layer on the outer ring width surface and the outer ring width surface. As a result, there is a concern that the insulating resin layer may peel off from the outer ring width surface.

[0015] In addition, if the adhesion force of the insulating resin layer to the outer ring is insufficient, during the operation of the insulated rolling bearing, a phenomenon (creep) occurs in which the insulating resin layer moves circumferentially relative to the outer ring, and there is a concern that the insulating resin layer may be worn, cracked, etc.

[0016] Therefore, in order to prevent the insulating resin layer from peeling off from the outer ring width surface or the insulating resin layer from creeping relative to the outer ring, in Patent Documents 1 and 2, two square grooves with a rectangular cross-section extending in the circumferential direction are formed on the outer peripheral surface of the outer ring, and the resin of the insulating resin layer enters into these square grooves, thereby preventing the insulating resin layer from peeling off from the outer peripheral surface of the outer ring. Similarly, in Patent Document 1, two square grooves with a rectangular cross-section extending in the circumferential direction are also formed on the inner peripheral surface of the inner ring, and the resin of the insulating resin layer enters into these square grooves.

[0017] In addition, in Patent Document 2, a rectangular groove in cross-section extending circumferentially is also formed in the outer peripheral surface area, and the resin of the insulating resin layer enters this groove, thereby preventing the insulating resin layer from peeling off from the outer peripheral surface area.

[0018] Patent Document 1: Japanese Patent No. 3068311 Gazette

[0019] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2004 - 308735

[0020] [Problems of the First Invention]

[0021] However, when molding resin for forming the surface of the outer ring, during cooling after insert molding, the molding resin shrinks during molding, and the outer ring also shrinks in response to the temperature decrease. At this time, the amount of dimensional change due to the molding shrinkage of the molding resin is greater than the amount of dimensional change of the outer ring accompanying the temperature decrease. Therefore, there is a concern that the portion of the molding resin that enters the axially both ends of the inner circumference of the outer ring may float up from the inner surface of the molding recess.

[0022] For example, consider Figure 7 the comparative example shown. In this comparative example, the molding resin 31 on the surface of the outer ring 30 has: an outer peripheral insulating portion 32 that covers the outer periphery of the outer ring 30; an end face insulating portion 34 that covers the axially both end faces 33 on both sides of the outer ring 30; and an end inner peripheral insulating portion 36 that extends axially inward from the radially inner end of the end face insulating portion 34 and enters the molding recess 35.

[0023] Here, as Figure 8 , Figure 9 shown, the concave side 37 of the molding recess 35 facing axially outward is generally formed, for ease of machining, as an inclined surface having a displacement inclined toward the radially inner side (downward in the figure) and axially inward (leftward in the figure), or a plane perpendicular to the axis ( Figure 8 shows an example of the former, Figure 9 shows an example of the latter). That is, generally, the angle θ formed by the concave side 37 of the molding recess 35 facing axially outward with respect to the axis is 90° or more ( Figure 8 the angle θ shown is greater than 90°, Figure 9 the angle θ shown is 90°).

[0024] If this molding resin 31 is formed by insert molding, during cooling after insert molding, the molding resin 31 shrinks during molding, and the outer ring 30 also shrinks in response to the temperature decrease. At this time, the amount of dimensional change due to the molding shrinkage of the molding resin 31 is greater than the amount of dimensional change of the outer ring 30 accompanying the temperature decrease. In addition, as Figure 8 , Figure 9As shown, the corner 38 where the axial end face 33 of the outer ring 30 intersects the inner surface of the molding recess 35 restricts the movement of the molding resin 31. Therefore, in the connecting portion between the inner peripheral insulating portion 36 and the end face insulating portion 34 at the end of the molding resin 31, as Figure 8 , Figure 9 the arrows indicate, the resin moves in such a way that the amount of resin movement increases as it gets farther from the corner 38. As a result, as shown by the dashed line in the figure, there is a concern that the inner peripheral insulating portion 36 at the end of the molding resin 31 deforms in a manner that it flexes radially inward with the connecting portion between the inner peripheral insulating portion 36 and the end face insulating portion 34 as the center and floats from the inner surface of the molding recess 35.

[0025] As Figure 8 , Figure 9 the dashed line shows, if the inner peripheral insulating portion 36 at the end of the molding resin 31 floats from the inner surface of the molding recess 35, a gap is generated between the inner peripheral insulating portion 36 at the end of the molding resin 31 and the inner surface of the molding recess 35. Therefore, lubricant intrudes into this gap, and creep of the molding resin 31 (circumferential movement of the molding resin 31 relative to the outer ring 30) is likely to occur.

[0026] Similarly, regarding the molding resin on the inner ring side, since the amount of dimensional change due to the molding shrinkage of the molding resin is greater than the dimensional change of the inner ring accompanying the temperature decrease, there is also a concern that the portions of the molding resin that enter the molding recesses at the axial both ends of the outer periphery of the inner ring float from the inner surface of the molding recess.

[0027] The problem to be solved by the first invention is to provide an insulating rolling bearing that can prevent the molding resin from floating from the inner surface of the molding recess due to the molding shrinkage of the resin.

[0028] [Problem of the second invention]

[0029] In order to prevent the peeling of the insulating resin layer, the insulating rolling bearings of Patent Documents 1 and 2 are provided with two rectangular-section square grooves on the outer ring, and the resin of the insulating resin layer enters into these square grooves. However, since the square grooves with a rectangular section are usually formed by cutting, a high processing cost is required. Therefore, an insulating rolling bearing with a lower price and excellent adhesion of the insulating resin layer is desired. The same problem also exists for the insulating resin layer on the inner ring side of Patent Document 1.

[0030] The insulating rolling bearing of Patent Document 2 forms square grooves with a rectangular section extending in the circumferential direction not only on the outer peripheral surface of the outer ring but also on the outer ring width surface, thereby achieving an improvement in the adhesion force of the insulating resin layer to the outer ring. However, not only the processing of the outer peripheral surface of the outer ring but also the processing of the outer ring width surface is the main cause of the increase in processing cost.

[0031] The problem to be solved by the second invention is to provide an insulating rolling bearing that can prevent peeling and creep of the insulating resin layer and is low-cost. Summary of the Invention

[0032] To solve the above problems, in the first invention, an insulating rolling bearing having the following structure is provided.

[0033] [Structure 1]

[0034] An insulating rolling bearing having:

[0035] An outer ring;

[0036] An inner ring disposed radially inside the outer ring;

[0037] A plurality of rolling elements assembled between the outer ring and the inner ring; and

[0038] An insulating molded resin covering the outer periphery of the outer ring and the axial end faces on both sides of the outer ring,

[0039] Annular molded recesses are formed at both axial ends of the inner periphery of the outer ring, and the molded recesses open to the axial end faces of the outer ring and extend in the circumferential direction,

[0040] The molded resin has: an outer peripheral insulating portion covering the outer periphery of the outer ring; an end face insulating portion covering the axial end faces of the outer ring; and an end inner peripheral insulating portion extending axially inward from the radially inner end of the end face insulating portion and entering the molded recess, and at least a part of the recess side face of the molded recess facing axially outward is covered by the end inner peripheral insulating portion,

[0041] The insulating rolling bearing is characterized in that

[0042] The portion of the recess side face covered by the end inner peripheral insulating portion of the molded resin is formed with an inclined surface that is inclined toward the radially outer side and displaced axially inward.

[0043] If this structure is adopted, the portion of the recess side face of the molded recess covered by the end inner peripheral insulating portion of the molded resin has an inclination that is displaced axially outward toward the radially inner side. Therefore, as the end inner peripheral insulating portion of the molded resin moves radially inward, an axial interference amount is generated between the end inner peripheral insulating portion of the molded resin and the recess side face of the molded recess. Therefore, the end inner peripheral insulating portion of the molded resin is not likely to be deformed such that it deflects radially inward with the connection portion between the end inner peripheral insulating portion and the end face insulating portion as the center, and it is possible to prevent the end inner peripheral insulating portion of the molded resin from floating from the inner surface of the molded recess due to the molding shrinkage of the resin.

[0044] [Structure 2]

[0045] The insulated rolling bearing according to Structure 1, wherein,

[0046] The above inclined surface is an annular conical table surface at an angle of 87° or less with respect to the axial direction.

[0047] If this structure is adopted, it is possible to reliably prevent the inner peripheral insulating portion at the end of the molded resin from deforming in such a way that it deflects radially inward with the connection portion between the inner peripheral insulating portion at the end and the end face insulating portion as the center.

[0048] [Structure 3]

[0049] The insulated rolling bearing according to Structure 1 or 2, wherein,

[0050] The side surface of the recess has: a molded portion covered by the above-mentioned inner peripheral insulating portion at the end; and a non-molded portion that is not covered by the above-mentioned inner peripheral insulating portion at the end and exposes the surface of the outer ring,

[0051] The radial height dimension of the above non-molded portion is set to 1.0 mm or more.

[0052] If this structure is adopted, a non-molded portion with a radial height dimension of 1.0 mm or more is provided on the side surface of the recess facing the axial outside. Therefore, when the outer ring is fixed inside the mold for insert molding of the resin, the non-molded portion can be brought into contact with the mold to fix the outer ring. Therefore, the fixing of the outer ring relative to the mold is stable, and burrs of the molded resin can be prevented.

[0053] [Structure 4]

[0054] The insulated rolling bearing according to Structure 3, wherein,

[0055] The above non-molded portion is formed into an annular plane perpendicular to the axial direction.

[0056] If this structure is adopted, the non-molded portion is formed into an annular plane perpendicular to the axial direction. Therefore, it is easy to manage the dimensional accuracy of the portion of the insert molding die that the non-molded portion contacts, and the fixing of the outer ring relative to the mold can be made particularly stable effectively.

[0057] [Structure 5]

[0058] The insulated rolling bearing according to any one of Structures 1 to 4, wherein,

[0059] The axial distance from the side surface of the above recess to the surface of the end face insulating portion is set to 2.25 mm or more.

[0060] If this structure is adopted, the axial distance from the concave side of the molded recess on the outer ring to the surface of the end face insulating portion of the molded resin is 2.25 mm or more. Therefore, when assembling the bearing by bringing the molded resin on the outer ring side into contact with the axial contact surface on the inner circumference of the housing, the creepage distance from this contact surface to the outer ring can be ensured, and electric erosion can be effectively prevented.

[0061] [Structure 6]

[0062] Regarding the insulated rolling bearing described in any one of Structures 1 to 5,

[0063] A relief groove is formed on the concave bottom surface of the molded recess facing radially inward, and the relief groove extends in the circumferential direction with a cross-sectional shape that is recessed radially outward.

[0064] If this structure is adopted, a relief groove that extends in the circumferential direction with a cross-sectional shape that is recessed radially outward is formed on the concave bottom surface of the molded recess. Therefore, by the fitting of the inner peripheral insulating portion at the end of the molded resin and the relief groove of the molded recess, the movement of the inner peripheral insulating portion at the end of the molded resin in the axial outward direction is restricted, and the inner peripheral insulating portion at the end of the molded resin is not easily separated from the concave side of the molded recess. Therefore, by the inclination of the concave side of the molded recess, it is possible to particularly effectively prevent the inner peripheral insulating portion at the end of the molded resin from floating up from the inner surface of the molded recess.

[0065] [Structure 7]

[0066] An insulated rolling bearing having:

[0067] An outer ring;

[0068] An inner ring disposed radially inward of the outer ring;

[0069] A plurality of rolling elements assembled between the outer ring and the inner ring; and

[0070] An insulating molded resin covering the inner circumference of the inner ring and the axial end faces on both sides of the inner ring,

[0071] Annular molded recesses are formed at both axial ends of the outer circumference of the inner ring, and the molded recesses open to the axial end faces of the inner ring and extend in the circumferential direction,

[0072] The molded resin has: an inner peripheral 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 outer peripheral insulating portion extending from the radially outer end of the end face insulating portion axially inward and entering the molded recess, and at least a part of the concave side of the molded recess facing axially outward is covered by the end outer peripheral insulating portion,

[0073] The characteristic of the above insulated rolling bearing is that,

[0074] The portion of the side surface of the concave portion covered by the end peripheral insulating portion is formed with an inclined surface that is inclined and displaced axially outward toward the radially outer side.

[0075] If this structure is adopted, the portion of the side surface of the molded concave portion covered by the end peripheral insulating portion of the molded resin has an inclination that is displaced axially outward toward the radially outer side. Therefore, as the end peripheral insulating portion of the molded resin moves radially outward, an axial interference amount is generated between the end peripheral insulating portion of the molded resin and the side surface of the molded concave portion. Therefore, it is difficult for the end peripheral insulating portion of the molded resin to be deformed such that it deflects radially outward with the connection portion between the end peripheral insulating portion and the end face insulating portion as the center, and it is possible to prevent the end peripheral insulating portion of the molded resin from floating from the inner surface of the molded concave portion due to the molding shrinkage of the resin.

[0076] [Structure 8]

[0077] According to the insulated rolling bearing described in Structure 7, wherein,

[0078] The inclined surface is an annular conical table surface at an angle of 87° or less with respect to the axial direction.

[0079] If this structure is adopted, it is possible to reliably prevent the end peripheral insulating portion of the molded resin from being deformed such that it deflects radially outward with the connection portion between the end peripheral insulating portion and the end face insulating portion as the center.

[0080] [Structure 9]

[0081] According to the insulated rolling bearing described in Structure 7 or 8, wherein,

[0082] The side surface of the concave portion has:

[0083] A molded portion covered by the end peripheral insulating portion; and a non-molded portion that is not covered by the end peripheral insulating portion and exposes the surface of the inner ring,

[0084] The radial height dimension of the non-molded portion is set to 1.0 mm or more.

[0085] If this structure is adopted, a non-molded portion having a radial height dimension of 1.0 mm or more is provided on the side surface of the molded concave portion facing axially outward. Therefore, when the inner ring is fixed inside the mold for insert molding of the resin, the non-molded portion can be brought into contact with the mold to fix the inner ring. Therefore, the inner ring is stably fixed with respect to the mold, and it is possible to prevent burrs from being generated in the molded resin.

[0086] [Structure 10]

[0087] According to the insulated rolling bearing described in Structure 9, wherein,

[0088] The above non-molded portion is formed into an annular plane perpendicular to the axis.

[0089] If this structure is adopted, the non-molded portion is formed into an annular plane perpendicular to the axis. Therefore, it is easy to manage the dimensional accuracy of the portion of the insert molding die that comes into contact with the non-molded portion, and the fixation of the inner ring relative to the die can be made particularly stable effectively.

[0090] [Structure 11]

[0091] Regarding the insulated rolling bearing according to any one of Structures 7 to 10, wherein

[0092] The axial distance from the side surface of the above-mentioned recess to the surface of the end face insulating portion is set to be 2.25 mm or more.

[0093] If this structure is adopted, the axial distance from the side surface of the molding recess of the inner ring to the surface of the end face insulating portion of the molding resin is 2.25 mm or more. Therefore, when assembling the bearing by bringing the molding 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 this abutting surface to the inner ring can be ensured, and electric erosion can be effectively prevented.

[0094] [Structure 12]

[0095] Regarding the insulated rolling bearing according to any one of Structures 7 to 11, wherein

[0096] A relief groove is formed on the bottom surface of the molding recess facing the radially outer side, and the relief groove extends in the circumferential direction with a cross-sectional shape recessed toward the radially inner side.

[0097] If this structure is adopted, a relief groove extending in the circumferential direction with a cross-sectional shape recessed toward the radially inner side is formed on the bottom surface of the molding recess. Therefore, by the fitting of the outer peripheral insulating portion at the end of the molding resin with the relief groove of the molding recess, the movement of the outer peripheral insulating portion at the end of the molding resin toward the axially outer side is restricted, and the outer peripheral insulating portion at the end of the molding resin is not easily separated from the side surface of the molding recess. Therefore, by the inclination of the side surface of the molding recess, it is possible to particularly effectively prevent the outer peripheral insulating portion at the end of the molding resin from floating up from the inner surface of the molding recess.

[0098] In addition, in order to solve the above problems, in the second invention, an insulated rolling bearing having the following structure is provided.

[0099] [Structure 13]

[0100] An insulated rolling bearing having:

[0101] An outer ring;

[0102] An inner ring disposed radially inside the above-mentioned outer ring;

[0103] A plurality of rolling elements, assembled between the outer ring and the inner ring; and

[0104] At least one of an insulating resin layer continuously formed on the entire outer peripheral surface of the outer ring and on the outer ring side of the outer ring web surfaces on both axial sides of the outer ring and an insulating resin layer continuously formed on the entire inner peripheral surface of the inner ring and on the inner ring side of the inner ring web surfaces on both axial sides of the inner ring,

[0105] The insulating rolling bearing is characterized in that,

[0106] A knurling portion is provided on the surface of the outer peripheral surface of the outer ring and the inner peripheral surface of the inner ring where the insulating resin layer is formed. The knurling portion allows the resin for forming the insulating resin layer to enter and is composed of a plurality of V-shaped grooves arranged in parallel at a constant pitch.

[0107] If this structure is adopted, when an insulating resin layer is formed on the outer peripheral surface of the outer ring, a knurling portion composed of a plurality of V-shaped grooves is provided on the outer peripheral surface of the outer ring, and the resin for forming the insulating resin layer enters into these V-shaped grooves. Therefore, the contact area between the insulating resin layer and the outer ring is large. As a result, the adhesion force between the insulating resin layer and the outer ring is large, and thus it is possible to prevent the offset between the insulating resin layer and the outer ring caused by the difference between the molding shrinkage rate of the insulating resin layer after forming the insulating resin layer by insert molding and the shrinkage rate accompanying the temperature reduction of the outer ring. Therefore, it is possible to prevent the insulating resin layer from peeling off from the outer ring web surface or creeping relative to the outer ring. In addition, when an axial weld line is generated in the insulating resin layer, due to the circumferential tensile force generated by the shrinkage after injection molding, cracks may occur in the insulating resin layer starting from the weld line, but this situation can also be prevented.

[0108] Similarly, when an insulating resin layer is formed on the inner peripheral surface of the inner ring, it is possible to prevent the insulating resin layer from peeling off from the inner ring web surface or creeping relative to the inner ring.

[0109] In addition, the plurality of V-shaped grooves arranged in parallel at a constant pitch of the knurling portion can be formed by roll-type knurling, so the processing cost is low.

[0110] [Structure 14]

[0111] According to the insulating rolling bearing described in Structure 13, wherein,

[0112] The knurling portion is a diamond knurling portion having a plurality of V-shaped grooves extending obliquely with respect to the axial direction in a first direction and a plurality of V-shaped grooves extending in a direction different from the extending direction of the V-shaped grooves in the first direction and the V-shaped grooves in the first direction and the V-shaped grooves in the second direction intersecting each other.

[0113] If this structure is adopted, the knurled portion through which the resin for forming the insulating resin layer enters is composed of V-grooves extending in a first direction and V-grooves extending in a second direction, which are different from each other. Therefore, when forming the insulating resin layer on the outer peripheral surface of the outer ring, it is possible to effectively prevent the axial displacement and the circumferential displacement between the insulating resin layer and the outer ring in both directions. Similarly, when forming the insulating resin layer on the inner peripheral surface of the inner ring, it is possible to effectively prevent the axial displacement and the circumferential displacement between the insulating resin layer and the inner ring in both directions.

[0114] [Structure 15]

[0115] In the insulating rolling bearing described in Structure 13,

[0116] The above-mentioned knurled portion is an axial straight-knurled portion composed of a plurality of V-grooves extending in the axial direction.

[0117] If this structure is adopted, the knurled portion through which the resin for forming the insulating resin layer enters is composed of a plurality of V-grooves extending in the axial direction. The extending direction of the V-grooves constituting the knurled portion is the axial direction, that is, a direction perpendicular to the circumferential direction. Therefore, when forming the insulating resin layer on the outer peripheral surface of the outer ring, it is possible to reliably prevent the circumferential displacement between the insulating resin layer and the outer ring, and particularly effectively prevent the creeping of the insulating resin layer on the outer ring side. Similarly, when forming the insulating resin layer on the inner peripheral surface of the inner ring, it is possible to reliably prevent the circumferential displacement between the insulating resin layer and the inner ring, and particularly effectively prevent the creeping of the insulating resin layer on the inner ring side.

[0118] [Structure 16]

[0119] In the insulating rolling bearing described in Structure 13,

[0120] The above-mentioned knurled portion is a circumferential straight-knurled portion composed of a plurality of V-grooves extending in the circumferential direction.

[0121] If this structure is adopted, the knurled portion through which the resin for forming the insulating resin layer enters is composed of a plurality of V-grooves extending in the circumferential direction. The extending direction of the V-grooves constituting the knurled portion is the circumferential direction, that is, a direction perpendicular to the axial direction. Therefore, when forming the insulating resin layer on the outer peripheral surface of the outer ring, it is possible to reliably prevent the axial displacement between the insulating resin layer and the outer ring, and particularly effectively prevent the peeling of the insulating resin layer on the outer ring side from the outer ring width surface. Similarly, when forming the insulating resin layer on the inner peripheral surface of the inner ring, it is possible to reliably prevent the axial displacement between the insulating resin layer and the inner ring, and particularly effectively prevent the peeling of the insulating resin layer on the inner ring side from the inner ring width surface.

[0122] [Structure 17]

[0123] The insulated rolling bearing according to any one of Structures 13 to 16, wherein,

[0124] The above knurled portion is provided on the entire surface where the insulating resin layer is formed on the outer peripheral surface of the outer ring and the inner peripheral surface of the inner ring.

[0125] If this structure is adopted, when an insulating resin layer is formed on the outer peripheral surface of the outer ring, the knurled portion is provided on the entire outer peripheral surface of the outer ring. Therefore, the total surface area of the knurled portion for the resin to enter for forming the insulating resin layer is large. Therefore, the contact area between the insulating resin layer and the outer ring is large, and thus the offset between the insulating resin layer and the outer ring can be effectively prevented. Similarly, when an insulating resin layer is formed on the inner peripheral surface of the inner ring, the offset between the insulating resin layer and the inner ring can be effectively prevented.

[0126] [Structure 18]

[0127] The insulated rolling bearing according to any one of Structures 13 to 16, wherein,

[0128] The above knurled portion is provided only on an axial part of the surface where the insulating resin layer is formed on the outer peripheral surface of the outer ring and the inner peripheral surface of the inner ring, and the other part of the surface is formed as a cylindrical surface without the knurled portion.

[0129] If this structure is adopted, when an insulating resin layer is formed on the outer peripheral surface of the outer ring, a part of the outer peripheral surface in the axial direction is formed as a cylindrical surface. Therefore, grinding processing of the outer raceway groove, outer ring width surface, etc. of the outer ring can be carried out with high precision based on this cylindrical surface. In addition, the boundary between the knurled portion and the cylindrical surface becomes a step extending in the circumferential direction, so that the axial offset between the insulating resin layer and the outer ring can be prevented. Similarly, when an insulating resin layer is formed on the inner peripheral surface of the inner ring, grinding processing of the inner raceway groove, inner ring width surface, etc. of the inner ring can be carried out with high precision, and in addition, the axial offset between the insulating resin layer and the inner ring can be prevented.

[0130] [Structure 19]

[0131] The insulated rolling bearing according to any one of Structures 13 to 18, wherein,

[0132] The above outer ring width surface and the above inner ring width surface are flat surfaces without grooves.

[0133] If this structure is adopted, since no grooves are provided on the outer ring width surface and the inner ring width surface, the surfaces to be processed are only the outer peripheral surface of the outer ring and the inner peripheral surface of the inner ring. The surfaces to be processed are few, and the cost is low.

[0134] [Structure 20]

[0135] The insulated rolling bearing according to any one of the structures 13 to 19, wherein,

[0136] The pitch of the V-shaped grooves of the knurled portion is 0.628 to 1.571 mm, and the depth of the V-shaped grooves of the knurled portion is 0.264 to 0.652 mm.

[0137] If this structure is adopted, the V-shaped grooves of the knurled portion are formed according to the dimensions of the knurled pattern specified in Japanese Industrial Standard (JIS B0951 "Knurled Pattern"), so that it can be processed with a general-purpose knurling tool and the cost is low.

[0138] [Structure 21]

[0139] The insulated rolling bearing according to any one of the structures 13 to 20, wherein,

[0140] A mountain portion having a triangular cross-section that separates the V-shaped grooves from each other is formed between adjacent V-shaped grooves.

[0141] The thickness of the insulating resin layer at the position of the top of the mountain portion is set to be 0.8 mm or more and 2.0 mm or less.

[0142] If this structure is adopted, the thickness of the insulating resin layer is 0.8 mm or more, so that the fluidity of the resin during injection molding is good and the insulation performance is high.

[0143] [Structure 22]

[0144] The insulated rolling bearing according to any one of the structures 13 to 21, wherein,

[0145] The insulating resin layer is formed of a resin having a molding shrinkage rate of 0.2% or more.

[0146] [Structure 23]

[0147] The insulated rolling bearing according to any one of the structures 13 to 22, wherein,

[0148] The insulating resin layer has a linear expansion coefficient of 1.0×10 -5 / °C or more in the axial direction and a linear expansion coefficient of 2.0×10 -5 / °C or more in the circumferential direction.

[0149] [Structure 24]

[0150] The insulated rolling bearing according to any one of the structures 13 to 23, wherein,

[0151] The insulating resin layer is formed of a resin having an insulation breakdown strength of 1 kV / mm or more.

[0152] If this structure is adopted, the dielectric breakdown strength of the resin forming the insulating resin layer is 1 kV / mm or more, so the insulation performance is high.

[0153] The insulating rolling bearing of the first invention can prevent the molded resin from floating up from the inner surface of the molded recess due to the molding shrinkage of the resin.

[0154] The insulating rolling bearing of the second invention can prevent peeling and creep of the insulating resin layer and has a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0155] Figure 1 is a cross-sectional view showing an insulating rolling bearing according to a first embodiment of the first invention.

[0156] Figure 2 is Figure 1 an enlarged view of the vicinity of the molded recess on the inner circumference of the end portion of the outer ring of

[0157] Figure 3 is Figure 2 a view showing a second embodiment of the first invention corresponding to

[0158] Figure 4 is Figure 2 a view showing a third embodiment of the first invention corresponding to

[0159] Figure 5 is Figure 2 a view showing a fourth embodiment of the first invention corresponding to

[0160] Figure 6 is Figure 1 a view showing a fifth embodiment of the first invention corresponding to

[0161] Figure 7 is a cross-sectional view of the outer ring of an insulating rolling bearing of a comparative example.

[0162] Figure 8 is Figure 7 an enlarged view of the vicinity of the molded recess on the inner circumference of the end portion of the outer ring of

[0163] Figure 9 is Figure 8 a view showing another comparative example of the molded recess shown in

[0164] Figure 10 is a partial cross-sectional view of an insulating rolling bearing according to a first embodiment of the second invention.

[0165] Figure 11 is Figure 10 an enlarged view showing the vicinity of the outer ring of

[0166] Figure 12 is a perspective view showing the outer peripheral surface of the outer ring by cutting away a part of the insulating resin layer of Figure 10 .

[0167] Figure 13 is a partial cross-sectional view of an insulating rolling bearing according to a second embodiment of the second invention.

[0168] Figure 14 is a view showing an enlarged view of the vicinity of the outer ring of Figure 13 .

[0169] Figure 15 is a perspective view showing the outer peripheral surface of the outer ring by cutting away a part of the insulating resin layer of Figure 13 .

[0170] Figure 16 is a partial cross-sectional view of an insulating rolling bearing according to a third embodiment of the second invention.

[0171] Figure 17 is a view showing an enlarged view of the vicinity of the outer ring of Figure 16 .

[0172] Figure 18 is a perspective view showing the outer peripheral surface of the outer ring by cutting away a part of the insulating resin layer of Figure 16 .

[0173] Figure 19 is a partial cross-sectional view of an insulating rolling bearing according to a fourth embodiment of the second invention.

[0174] Figure 20 is a view showing an enlarged view of the vicinity of the outer ring of Figure 19 .

[0175] Figure 21 is a perspective view showing the outer peripheral surface of the outer ring by cutting away a part of the insulating resin layer of Figure 19 .

[0176] Explanation of reference numerals

[0177] 1... Outer ring; 2... Inner ring; 3... Rolling elements; 5... Molded resin; 5a... Outer peripheral insulating portion; 5b... End face insulating portion; 5c... Inner peripheral insulating portion at the end; 5d... Inner peripheral insulating portion; 5e... End face insulating portion; 5f... Outer peripheral insulating portion at the end; 6... Axial end face; 8... Molded recess; 10... Axial end face; 13... Side surface of the recess; 14... Bottom surface of the recess; 15... Molded portion; 16... Non-molded portion; 18... Relief groove; H... Radial height dimension; W... Axial distance; θ... Angle; 41... Outer ring; 42... Inner ring; 43... Rolling elements; 44... Insulating resin layer; 46... Width of the outer ring; 50... Width of the inner ring; 57... V-shaped groove; 57a... V-shaped groove in the first direction; 57b... V-shaped groove in the second direction; 58... Knurled portion; 60... Crest portion; 62... Cylindrical surface; p... Pitch; h... Depth; t... Thickness. Detailed implementation

[0178] Figure 1 An insulating rolling bearing according to a first embodiment of the first invention is shown. The insulating rolling bearing has: an outer ring 1; an inner ring 2 coaxially disposed radially inside the outer ring 1; a plurality of rolling elements 3 assembled at intervals in the circumferential direction between the outer ring 1 and the inner ring 2; an annular retainer 4 for maintaining the circumferential interval of the plurality of rolling elements 3; and a molded 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 steel.

[0179] The axial direction refers to the direction parallel to the central axis of the outer ring 1 (the central axis of the bearing), the radial direction refers to the direction perpendicular to the central axis of the outer ring 1, and the circumferential direction refers to the direction along the circumference surrounding 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. The axial inner side refers to the direction along the axial direction approaching the axial center of the outer ring 1 and the inner ring 2, and the axial outer side refers to the direction along the axial direction away from the axial center of the outer ring 1 and the inner ring 2.

[0180] The outer periphery 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 periphery of the outer ring 1, an outer raceway groove 7 for the rolling elements 3 to roll and contact, a pair of molded recesses 8, and a cylindrical surface 9 with a constant inner diameter connecting between the outer raceway groove 7 and the molded recesses 8 are formed. The outer raceway groove 7 is formed at the axial center of the inner periphery of the outer ring 1, and the cylindrical surface 9 is formed adjacent to the axial outer side of the outer raceway groove 7. The pair of molded recesses 8 are formed at the axial ends of the inner periphery of the outer ring 1. The molded recesses 8 are recesses recessed radially outward with respect to the cylindrical surface 9, opening to the axial end face 6 of the outer ring 1 and extending in the circumferential direction.

[0181] 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 axis. On the outer circumference of the inner ring 2, an inner ring raceway groove 11 for the rolling elements 3 to rollingly contact and a cylindrical surface 12 with a constant outer diameter connecting 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 outer side in the axial direction of the inner ring raceway groove 11.

[0182] The rolling elements 3 are radially sandwiched between the outer ring raceway groove 7 and the inner ring raceway groove 11. Here, the rolling elements 3 are balls. The outer ring raceway groove 7 is an arc groove whose cross-sectional shape orthogonal 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 orthogonal to the circumferential direction is symmetric with respect to the axial center of the inner ring 2.

[0183] The molded 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 molded resin 5 is formed by insert molding. That is, the outer ring 1 is placed inside a mold (not shown), and molten resin is injected into the inside of the mold, whereby the molded resin 5 is formed on the surface of the outer ring 1. The molded 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.

[0184] The molded resin 5 is formed of a resin having insulating properties. Specifically, the molded resin 5 is formed of a resin having a dielectric breakdown strength of 1 kV / mm or more. In addition, a resin having a comparative tracking index (CTI value) of 600 V or more is used as the resin for forming the molded resin 5. Here, the comparative tracking index refers to the comparative tracking index (CTI value) obtained by measuring according to the method specified in Japanese Industrial Standard JIS C2134:2007 "Methods for the determination of proof and comparative tracking indices of solid insulating materials" (standard corresponding to IEC60112).

[0185] As the resin for forming the molded resin 5, a resin in which a fiber reinforcing material is added 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, insulating materials such as glass fiber and aramid fiber can be used.

[0186] The molded 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 into the molding recess 8. Here, the end face insulating portion 5b, the molding recess 8, and the structures in the vicinity thereof on the axial one side (the right side in the figure) are the same structures that are axially centrally symmetric compared to the end face insulating portion 5b, the molding recess 8, and the structures in the vicinity thereof on the axial other side (the left side in the figure). Therefore, hereinafter, the end face insulating portion 5b, the molding recess 8, and the structures in the vicinity thereof on the axial one side will be described, and the description of the structures on the axial other side will be omitted.

[0187] As Figure 2 shown, the molding recess 8 has: a recess side face 13 that is connected to the axially outer end (the right end in the figure) of the cylindrical surface 9 of the inner periphery of the outer ring 1; and a recess bottom face 14 that is connected to the radially inner end (the lower end in the figure) of the axial end face 6 of the outer ring 1. The recess side face 13 is a face that faces axially outward (the right side in the figure), and the recess bottom face 14 is a face that faces radially inward (the lower side in the figure).

[0188] The end inner peripheral insulating portion 5c of the molded resin 5 is formed to cover the radially outer portion of the recess side face 13 and the entire recess bottom face 14. The recess side face 13 has: a molded portion 15 that is covered by the end inner peripheral insulating portion 5c; and an unmolded portion 16 that is not covered by the end inner peripheral insulating portion 5c and exposes the surface of the steel material constituting the outer ring 1. The radially height dimension H of the unmolded portion 16 is set to be 1.0 mm or more.

[0189] The recess side face 13 (the molded portion 15 and the unmolded portion 16) is formed to have an inclined surface that is inclined toward the radially inner side (the lower side in the figure) and is displaced axially outward (the right end in the figure). The inclined surface is an annular conical table surface with an angle θ of 87° or less (preferably 85° or less) with respect to the axis. The axial distance W from the unmolded portion 16 of the recess side face 13 to the surface of the end face insulating portion 5b is set to be 2.25 mm or more. The recess bottom face 14 is formed as a cylindrical surface with a constant inner diameter along the axis.

[0190] The surface (the axially outer surface) of the end face insulating portion 5b of the molded resin 5 is formed as a planar shape perpendicular to the axis. The inner periphery of the end inner peripheral insulating portion 5c of the molded resin 5 is formed as a cylindrical shape with a constant inner diameter along the axis starting from the boundary position between the molded portion 15 and the unmolded portion 16 of the recess side face 13. The inner periphery of the end inner peripheral insulating portion 5c of the molded resin 5 intersects the surface of the end face insulating portion 5b of the molded resin 5 at a right angle.

[0191] This insulated rolling bearing can be assembled into Figure 1It is used with the housing 20 shown by the dashed line. On the inner periphery of the housing 20, there are: a cylindrical inner peripheral fitting surface 21 that fits with the outer peripheral insulating portion 5a of the molded resin 5; an axial abutting surface 22 that extends radially inward from the inner peripheral fitting surface 21; and an inner peripheral cylindrical surface 23 that extends from the radially inner end of the abutting surface 22 to the side opposite to the inner peripheral fitting surface 21 side. The insulating 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 periphery 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 inner peripheral insulating portion 5c of the molded resin 5.

[0192] However, if the molded resin 5 shown in Figure 1 is formed by insert molding, when the molded resin 5 shrinks during cooling after insert molding, 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 greater than the amount of dimensional change of the outer ring 1 accompanying the temperature decrease. In addition, Figure 2 at the corner portion 17 where the axial end face 6 of the outer ring 1 shown in

[0193] crosses the bottom surface 14 of the recess, the movement of the molded resin 5 is restricted. Therefore, in the connecting portion between the end inner peripheral insulating portion 5c and the end face insulating portion 5b of the molded resin 5, the resin moves more as it is farther from the corner portion 17. As a result, there is a concern that the end inner peripheral insulating portion 5c of the molded resin 5 deforms in a manner of deflecting radially inward with the connecting portion between the end inner peripheral insulating portion 5c and the end face insulating portion 5b as the center. Due to this deformation, there is a concern that the end inner peripheral insulating portion 5c floats from the bottom surface 14 of the recess.

[0194] Regarding this problem, for this insulating rolling bearing, as shown in Figure 2 the portion of the recess side surface 13 covered by the end inner peripheral insulating portion 5c of the molded resin 5 has an inclination that displaces axially outward toward the radially inner side. Therefore, along with the movement of the end inner peripheral insulating portion 5c of the molded resin 5 radially inward, an axial interference amount is generated between the end inner peripheral insulating portion 5c of the molded resin 5 and the recess side surface 13. Therefore, the end inner peripheral insulating portion 5c of the molded resin 5 is not likely to deform in a manner of deflecting radially inward with the connecting portion between the end inner peripheral insulating portion 5c and the end face insulating portion 5b as the center, and it is possible to prevent the end inner peripheral insulating portion 5c of the molded resin 5 from floating from the inner surface of the molding recess 8 due to the molding shrinkage of the resin.

[0195] In addition, for this insulated rolling bearing, the portion of the concave side surface 13 covered by the end inner peripheral insulating portion 5c of the molded 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 reliably prevent the end inner peripheral insulating portion 5c of the molded resin 5 from deforming such that it deflects radially inward with the connection portion between the end inner peripheral insulating portion 5c and the end face insulating portion 5b as the center.

[0196] In addition, for 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 of the molding recess 8 facing the axial outer side. Therefore, when the outer ring 1 is fixed inside the mold for insert molding of the resin, 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 relative to the mold is stable, and burrs of the molded resin 5 can be prevented.

[0197] In addition, for this insulated rolling bearing, the axial distance W from the concave side surface 13 of the molding recess 8 of the outer ring 1 to the surface of the end face insulating portion 5b of the molded resin 5 is 2.25 mm or more. Therefore, as Figure 1 shown by the dashed line, when the end face insulating portion 5b of the molded resin 5 is brought into contact with the axial abutting surface 22 on the inner periphery of the housing 20 for assembling the bearing, the creepage distance from the abutting surface 22 to the outer ring 1 can be ensured, and electric erosion can be effectively prevented.

[0198] That is, in recent years, the voltage applied to the electric motor for driving an electric vehicle is about 100 V. According to the standard EN61984 of the International Electrotechnical Commission IEC, when the pollution degree is 3 and the CTI value is 100 - 175 V, in order to ensure the creepage distance required for electrical insulation when applying this 100 V voltage, it is 2.25 mm or more. Therefore, when using this insulated rolling bearing of the embodiment as a rolling bearing for supporting the rotating shaft of the electric motor for driving an electric vehicle, or as a rolling bearing for supporting the rotating shaft of an e-Axle in which the electric motor, inverter, and transmission for driving an electric vehicle are integrated, if the axial distance W from the concave side surface 13 of the molding recess 8 of the outer ring 1 as Figure 2 shown to the surface of the end face insulating portion 5b is 2.25 mm or more, then the creepage distance between the outer ring 1 and the housing 20 as Figure 1 shown can be ensured to be 2.25 mm or more, and electric erosion can be effectively prevented.

[0199] Figure 3 This represents the second embodiment of the first invention. Compared with the first embodiment, only the structure of the concave side surface 13 is different, and the other structures are the same. Therefore, parts corresponding to the first embodiment are labeled with the same reference numerals and the description is omitted.

[0200] The molded portion 15 of the concave portion side surface 13 is formed to have an inclined surface that is inclined and displaced toward the radially inner side (downward in the figure) and axially outward (right end in the figure). The inclined surface is an annular conical table surface with 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 portion side surface 13 is formed as an annular flat surface perpendicular to the axial direction. The axial distance W from the non-molded portion 16 of the concave portion side surface 13 to the surface of the end face insulating portion 5b is set to be 2.25 mm or more. The concave portion bottom surface 14 is formed as a cylindrical surface with a constant inner diameter along the axial direction.

[0201] For the insulated rolling bearing of this embodiment, since the non-molded portion 16 of the concave portion side surface 13 is formed as an annular flat surface perpendicular to the axial direction, it is easy to manage the dimensional accuracy of the portion of the insert molding die that contacts the non-molded portion 16. Therefore, the fixing of the outer ring 1 relative to the die can be made particularly stable. In addition, it has the same effects as the first embodiment.

[0202] Figure 4 This represents the third embodiment of the first invention. Compared with the first embodiment, only the structure of the concave portion bottom surface 14 is different, and the other structures are the same. Therefore, the parts corresponding to the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

[0203] A relief groove 18 is formed in the concave portion bottom surface 14 of the molded concave portion 8, and the relief groove 18 extends in the circumferential direction with a cross-sectional shape that is recessed toward the radially outer side. That is, the concave portion bottom surface 14 is formed to have a portion (relief groove 18) that is displaced toward the radially outer side and axially inward (left side in the figure) in a cross-section orthogonal to the circumferential direction.

[0204] For the insulated rolling bearing of this embodiment, since a relief groove 18 that extends in the circumferential direction with a cross-sectional shape that is recessed toward the radially outer side is formed in the concave portion bottom surface 14 of the molded concave portion 8, the movement of the inner peripheral insulating portion 5c at the end of the molded resin 5 toward the axially outer side is restricted by the engagement of the inner peripheral insulating portion 5c at the end of the molded resin 5 with the relief groove 18 of the molded concave portion 8, and the inner peripheral insulating portion 5c at the end of the molded resin 5 is not easily separated from the concave portion side surface 13 of the molded concave portion 8. Therefore, by the inclination of the concave portion side surface 13 of the molded concave portion 8, it is possible to particularly effectively prevent the inner peripheral insulating portion 5c at the end of the molded resin 5 from floating up from the inner surface of the molded concave portion 8.

[0205] Figure 5 This represents the fourth embodiment of the first invention. The fourth embodiment replaces the structure of the concave portion side surface 13 of the first embodiment (refer to Figure 2 ) with the structure of the concave portion side surface 13 of the second embodiment (refer to Figure 3 ), and replaces the structure of the concave portion side surface 13 of the first embodiment (refer to Figure 2)The structure of the bottom surface 14 of the recess is replaced with the structure of the bottom surface 14 of the third embodiment (see Figure 4 ). Therefore, the same reference numerals are assigned to the corresponding parts of the above-described embodiments and the description thereof is omitted.

[0206] Figure 6 This shows a fifth embodiment of the first invention. The fifth embodiment is equivalent to reversing the relationship between the outer ring 1 and the inner ring 2 of the first embodiment. The same reference numerals are assigned to the corresponding parts of the first embodiment and the description thereof is omitted.

[0207] An inner ring raceway groove 11 for the rolling elements 3 to rollingly contact, a pair of molded recesses 8, and a cylindrical surface 12 having a constant outer diameter connecting the inner ring raceway groove 11 and the molded recess 8 are formed on the outer periphery of the inner ring 2. 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 axially outer side of the inner ring raceway groove 11. A pair of molded recesses 8 are formed at the axial ends of the outer periphery of the inner ring 2. The molded recess 8 is a groove that opens to the axial end surface 10 of the inner ring 2 and extends in the circumferential direction.

[0208] The molded 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 molded resin 5 is formed by insert molding. That is, the inner ring 2 is placed inside a mold (not shown), and molten resin is injected into the inside of the mold, whereby the molded resin 5 is formed on the surface of the inner ring 2. The molded 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.

[0209] The molded 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 peripheral insulating portion 5f that extends from the radially outer end of the end surface insulating portion 5e toward the axial inside and enters the molded recess 8.

[0210] Here, the molded recess 8, the inner peripheral insulating portion 5d, the end surface insulating portion 5e, and the end peripheral insulating portion 5f respectively correspond to the molded recess 8, the outer peripheral insulating portion 5a, the end surface insulating portion 5b, and the end inner peripheral insulating portion 5c of the first embodiment (see Figure 1 ). That is, Figure 6 The structures of the shown molded recess 8, inner peripheral insulating portion 5d, end surface insulating portion 5e, and end peripheral insulating portion 5f are the same structures in which only the radially outer side and the radially inner side of the molded recess 8, outer peripheral insulating portion 5a, end surface insulating portion 5b, and end inner peripheral insulating portion 5c of the first embodiment (see Figure 1 ) are reversed. In addition, the fifth embodiment has the same effects as the first embodiment.

[0211] The second embodiment (seeFigure 3 ) The third embodiment (refer to Figure 4 ) and the fourth embodiment (refer to Figure 5 ) are applied to the fifth embodiment ( Figure 6 ) in such a way that the radial outer side and the radial inner side are reversed in the structure of the molding recess 8.

[0212] In each of the above embodiments of the first invention, the case where balls are used as the rolling elements 3 has been described as an example, but other shaped rolling elements 3 such as cylindrical rollers can also be used.

[0213] Figures 10 to 12 An insulating rolling bearing according to the first embodiment of the second invention is shown. This insulating rolling bearing is a bearing used for supporting the rotating shaft of an electric motor for driving an electric vehicle, or for supporting the rotating shaft of an e-Axle in which an electric motor, an inverter, and a transmission for driving an electric vehicle are integrated.

[0214] This insulating rolling bearing has: an outer ring 41; an inner ring 42 disposed radially inside the outer ring 41; a plurality of rolling elements 43 assembled between the outer ring 41 and the inner ring 42; an insulating resin layer 44 on the outer ring side; and a retainer 45. Here, the rolling elements 43 are balls.

[0215] As Figure 11 shown, outer ring flanges 46 are formed on both axial sides of the outer ring 41. The outer ring flanges 46 are planes perpendicular to the axial direction. An outer ring raceway groove 47 for the rolling elements 43 to roll, a cylindrical surface 48 with a constant inner diameter adjacent to the outer ring raceway groove 47, and a chamfer portion 49 connecting the cylindrical surface 48 and the outer ring flange 46 are formed on the inner circumference of the outer ring 41. The outer ring raceway groove 47 is an arc groove having a concave arc-shaped cross section along the surface of the rolling element 43, and is formed to extend circumferentially at the axial center of the inner circumferential surface of the outer ring 41.

[0216] As Figure 10 shown, inner ring flanges 50 are formed on both axial sides of the inner ring 42. The inner ring flanges 50 are planes perpendicular to the axial direction. An inner ring raceway groove 51 for the rolling elements 43 to roll, a cylindrical surface 52 with a constant outer diameter adjacent to the inner ring raceway groove 51, and a chamfer portion 53 connecting the cylindrical surface 52 and the inner ring flange 50 are formed on the outer circumference of the inner ring 42. The inner ring raceway groove 51 is an arc groove having a concave arc-shaped cross section along the surface of the rolling element 43, and is formed to extend circumferentially at the axial center of the outer circumferential surface of the inner ring 42.

[0217] The outer ring 41, the inner ring 42, and the rolling elements 43 are all formed of metal (for example, high and medium carbon alloy steels, carburized steels, bearing steels, etc.).

[0218] As Figure 11As shown, the insulating resin layer 44 has: an outer peripheral insulating portion 54 that covers the outer peripheral surface of the outer ring 41; a width insulating portion 55 that covers the outer ring widths 46 on both sides; and a connecting portion 56 that connects the outer peripheral insulating portion 54 and the width insulating portion 55. The outer peripheral surface of the outer peripheral insulating portion 54 is formed as a cylindrical surface with a constant outer diameter, covering the entire outer peripheral surface of the outer ring 41. The width insulating portion 55 is formed as an annular plate shape that extends from the radially outer end of the outer ring width 46 to the center in the radial direction of the outer ring width 46. The width insulating portion 55 is not formed on the radially inner side of the center of the outer ring width 46, and the portion on the radially inner side of the center of the outer ring width 46 exposes the outer ring width 46. The outer periphery of the connecting portion 56 is formed in an R chamfer shape that smoothly connects with the outer peripheral insulating portion 54. Here, the outer peripheral insulating portion 54, the connecting portion 56, and the width insulating portion 55 are formed integrally. That is, the insulating resin layer 44 is continuously formed on the entire outer peripheral surface of the outer ring 41 and the outer ring widths 46 on both axial sides of the outer ring 41.

[0219] The insulating resin layer 44 is formed of a resin having insulating properties. Specifically, the insulating resin layer 44 is formed of a resin having a dielectric breakdown strength of 1 kV / mm or more (the measurement method is based on International Electrotechnical Commission IEC60243-1.). As the resin, polyphenylene sulfide resin (PPS), polyphthalamide resin (PPA), etc. can be used. By providing this insulating resin layer 44, the current path to the inside of the bearing is cut off, preventing the generation of sparks between the inner surface of the outer raceway groove 47 and the surface of the rolling element 43, or as Figure 10 shown, preventing the generation of sparks between the inner surface of the inner raceway groove 51 and the surface of the rolling element 43.

[0220] In addition, the resin forming the insulating resin layer 44 uses a resin added with a fiber reinforcing material. As the fiber reinforcing material, insulating materials such as glass fiber and aramid fiber are used. The resin has a molding shrinkage rate of 0.2% or more.

[0221] The insulating resin layer 44 is formed by insert molding. That is, the outer ring 41 is placed inside the mold, and molten resin is injected into the inside of the mold, thereby forming the insulating resin layer 44 on the surface of the outer ring 41. Here, the mold used for insert molding uses a mold having a disk-shaped gate instead of a needle-shaped gate as the gate for injecting molten resin into the inside of the mold. In addition, the disk-shaped gate is provided on one axial side of the mold. The insulating resin layer 44 is formed by injecting molten resin from the disk-shaped gate located on one axial side toward the other axial side. The linear expansion coefficient of a known injection molded part has anisotropy, and the direction perpendicular to the injection direction is larger than the direction parallel to the injection direction. Therefore, the circumferential linear expansion coefficient of the insulating resin layer 44 is higher than the axial linear expansion coefficient. The insulating resin layer 44 of the embodiment of the second invention has 1.0×10 in the axial direction -5The linear expansion coefficient above / ℃ has 2.0×10 -5 / ℃ or more in the circumferential direction. In addition, when the materials of the outer ring 41 and the inner ring 42 are steel, the linear expansion coefficients of the outer ring 41 and the inner ring 42 are about 1.1×10 -5 / ℃. The linear expansion coefficient is a value obtained by measuring according to the international standard ISO11359-2.

[0222] The axial width dimension of the outer ring 41 (the width dimension not including the insulating resin layer 44. The width dimension from one outer ring width surface 46 to the other outer ring width surface 46 on both sides) is smaller than the axial width dimension of the inner ring 42 (the width dimension from one inner ring width surface 50 to the other inner ring width surface 50 on both sides). Moreover, the width dimension of the insulating resin layer 44 and the outer ring 41 combined is equal to the width dimension of the inner ring 42.

[0223] A knurling portion 58 is provided on the entire outer peripheral surface of the outer ring 41. The knurling portion 58 is composed of a plurality of V-shaped grooves 57 arranged in parallel at a constant pitch, and the resin forming the insulating resin layer 44 enters into each V-shaped groove 57 constituting the knurling portion 58. The knurling portion 58 is a diamond knurling portion 58 having a plurality of V-shaped grooves 57a in a first direction extending obliquely with respect to the axial direction and a plurality of V-shaped grooves 57b in a second direction extending in a direction different from the extending direction of the V-shaped grooves 57a in the first direction, and the V-shaped grooves 57a in the first direction and the V-shaped grooves 57b in the second direction intersect each other. Chamfering is performed on the entire circumference at both axial ends of the outer peripheral surface of the outer ring 41.

[0224] The V-shaped grooves 57a in the first direction are formed to be inclined with respect to the axial direction toward one side in the circumferential direction at a specified inclination angle a. The V-shaped grooves 57b in the second direction are formed to be inclined with respect to the axial direction toward the other side in the circumferential direction at the same angle (inclination angle b) as the inclination angle a of the V-shaped grooves 57a in the first direction. The inclination angle a of the V-shaped grooves 57a in the first direction (and the inclination angle b of the V-shaped grooves 57b in the second direction) is set to 30° or 45° according to the Japanese Industrial Standard (JIS B0951 "Knurling Patterns"). That is, the inclination angle a of the V-shaped grooves 57a in the first direction (and the inclination angle b of the V-shaped grooves 57b in the second direction) is set to be 29° or more and 31° or less (30° in the figure) or 44° or more and 46° or less.

[0225] The outer ring width surface 46 is a flat surface without groove processing. That is, only the outer peripheral surface of the outer ring 41 among the outer peripheral surface of the outer ring 41 and the outer ring width surface 46 is processed with grooves (V-shaped grooves 57), and the outer ring width surface 46 is formed as a flat surface without being processed with grooves.

[0226] The retainer 45 is a crown-shaped retainer formed by a ring portion 59 and claw portions (not shown) protruding axially from the ring portion 59. Hemispherical pocket holes for receiving the balls are formed between the claw portions adjacent in the circumferential direction. The retainer 45 holds the rolling elements 43 at constant intervals in the circumferential direction by holding the balls in the respective pocket holes. The retainer 45 is formed of resin.

[0227] The pitch p of the V-shaped grooves 57a in the first direction and the V-shaped grooves 57b in the second direction constituting the knurling portion 58 is 0.628 to 1.571 mm, and the depth h of the V-shaped grooves 57a in the first direction and the V-shaped grooves 57b in the second direction (refer to Figure 11 ) is 0.264 to 0.652 mm. The V-shaped groove 57 having the depth h is obtained by knurling the mesh pattern of any one of the modules of m0.2, m0.3, and m0.5 described in the regulations in accordance with Japanese Industrial Standard (JIS B0951 “Knurling”).

[0228] As Figure 11 shown, between the adjacent V-shaped grooves 57a in the first direction, there are formed mountain portions 60 having a triangular cross-section that separate the V-shaped grooves 57a in the first direction from each other, and between the adjacent V-shaped grooves 57b in the second direction, there are also formed mountain portions 60 having a triangular cross-section that separate the V-shaped grooves 57b in the second direction from each other. As a result, as Figure 12 shown, the portion surrounded by the adjacent V-shaped grooves 57a in the first direction and the adjacent V-shaped grooves 57b in the second direction forms a pyramidal protrusion 61. The protrusions 61 are formed at constant intervals on the entire outer peripheral surface of the outer ring 41.

[0229] As Figure 11 shown, the insulating resin layer 44 is formed to have a thickness t of 0.8 mm or more (preferably 1.0 mm or more) and 2.0 mm or less at the top of the mountain portion 60. That is, the insulating resin layer 44 is formed such that the minimum thickness of the insulating resin layer 44 on the outer peripheral surface of the outer ring 41 is 0.8 mm or more (preferably 1.0 mm or more). In a cross-section orthogonal to the extending direction of the V-shaped groove 57a in the first direction, the angle formed by the two inclined surfaces forming the V-shaped groove 57a in the first direction is set to be 88° or more and 92° or less (for example, 90°). Similarly, in a cross-section orthogonal to the extending direction of the V-shaped groove 57b in the second direction, the angle formed by the two inclined surfaces forming the V-shaped groove 57b in the second direction is also set to be 88° or more and 92° or less (for example, 90°).

[0230] Both the V-shaped groove 57a in the first direction and the V-shaped groove 57b in the second direction are rolling grooves formed by the following roll-type knurling process, and have a shape along the V-shaped groove 57 (refer to Figure 10)Continuous metal structure of a bent shape. The metal structure of the V-groove 57 can be observed by cutting the outer ring 41 and corroding the cut surface with a corrosive solution containing nitric acid (such as nital).

[0231] The outer ring 41 is manufactured as follows. First, a circular outer ring blank is formed by forging a metal blank. Next, an outer ring raceway groove 47 extending in the circumferential direction is formed by turning at the axial center of the inner circumferential surface of the outer ring blank. Then, a knurling portion 58 (refer to Figure 12 ) of the V-groove 57 (refer to Figure 10 ) is formed on the outer circumferential surface of the outer ring blank by roll-type knurling. That is, by pressing a knurling tool having a concavo-convex shape with a reticulated pattern on the outer circumferential surface of the outer ring blank, the outer circumferential surface of the outer ring blank is plastically deformed into a concavo-convex shape of the reticulated pattern to form the V-groove 57 of the knurling portion 58 on the outer circumferential surface of the outer ring blank. Then, the outer ring blank is heat-treated. Then, grinding is performed on the outer ring width surface 46, the outer circumference, and the outer ring raceway groove 47 of the outer ring blank, respectively, and further superfinishing is performed on the outer ring raceway groove 47, thereby obtaining the outer ring 41.

[0232] Then, an insulating resin layer 44 is formed by insert molding. That is, the above-mentioned outer ring 41 after superfinishing is placed in a mold, and the mold is closed to perform injection molding (resin molding) of the resin, thereby forming the insulating resin layer 44 on the outer circumferential surface and the outer ring width surface 46 of the outer ring 41.

[0233] In the insulating rolling bearing of this embodiment, as Figure 10 shown, a knurling portion 58 composed of a plurality of V-grooves 57 is provided on the outer circumferential surface of the outer ring 41, and the resin for forming the insulating resin layer 44 enters into these V-grooves 57, so that the contact area between the insulating resin layer 44 and the outer ring 41 is large. Thus, the bonding force between the insulating resin layer 44 and the outer ring 41 is large, and therefore it is possible to prevent the shift between the insulating resin layer 44 and the outer ring 41 caused by the difference between the molding shrinkage rate of the insulating resin layer 44 after forming the insulating resin layer 44 by insert molding and the shrinkage rate accompanying the temperature decrease of the outer ring 41. Therefore, it is possible to prevent the insulating resin layer 44 from peeling off from the outer ring width surface 46 or creeping relative to the outer ring 41.

[0234] In addition, in the case where a weld line extending in the axial direction is generated in the insulating resin layer 44, cracks may be generated in the insulating resin layer 44 starting from the weld line due to the circumferential tensile force generated by the shrinkage after injection molding, but this can also be prevented.

[0235] In addition, the plurality of V-grooves 57 arranged in parallel at a constant pitch of the knurling portion 58 can be formed by roll-type knurling, so the processing cost is low.

[0236] In addition, for this insulated rolling bearing, the knurled portion 58 into which the resin for forming the insulating resin layer 44 enters is composed of a V-shaped groove 57a in the first direction and a V-shaped groove 57b in the second direction that extend in mutually different directions. Therefore, it is possible to effectively prevent displacement in two directions, namely, axial displacement between the insulating resin layer 44 and the outer ring 41 and circumferential displacement between the insulating resin layer 44 and the outer ring 41.

[0237] In addition, for this insulated rolling bearing, as Figure 12 shown, the knurled portion 58 is provided on the entire outer peripheral surface of the outer ring 41. Therefore, the total surface area of the knurled portion 58 into which the resin for forming the insulating resin layer 44 enters is large. As a result, the contact area between the insulating resin layer 44 and the outer ring 41 is large, and thus it is possible to effectively prevent displacement between the insulating resin layer 44 and the outer ring 41.

[0238] In addition, for the outer ring 41 of this insulated rolling bearing, as Figure 11 shown, no groove is provided in the outer ring width surface 46, and the surface for machining the groove is only the outer peripheral surface of the outer ring 41. The surface to be machined is small, and the cost is low.

[0239] In addition, for this insulated rolling bearing, as Figure 10 shown, the V-shaped grooves 57 of the knurled portion 58 are formed in accordance with the dimensions of the knurling pattern specified in Japanese Industrial Standard (JIS B0951 "Knurling Pattern"). Therefore, it is possible to machine with a general-purpose knurling tool, and the cost is low.

[0240] In addition, for this insulated rolling bearing, as Figure 11 shown, the thickness t of the insulating resin layer 44 is 0.8 mm or more. Therefore, the fluidity of the resin during injection molding is good, and the insulation performance is high.

[0241] In addition, for this insulated rolling bearing, the dielectric breakdown strength of the resin forming the insulating resin layer 44 is 1 kV / mm or more. Therefore, the insulation performance is high. In this case, for example, assuming a situation where the system voltage of an electric motor of an electric vehicle or an e-Axle is about 800 V, if the dielectric breakdown strength of the resin forming the insulating resin layer 44 is set to 1 kV / mm or more, by setting the thickness t of the insulating resin layer 44 to 0.8 mm or more, sufficient insulation performance can be ensured.

[0242] In addition, the pair of width insulating portions 55 of the insulating resin layer 44 sandwich the outer ring 41 from both axial sides. Therefore, it is possible to reliably prevent the insulating resin layer 44 from moving axially relative to the outer ring 41. Therefore, it is possible to reliably prevent axial displacement between the insulating resin layer 44 and the outer ring 41.

[0243] Figures 13 to 15An insulating rolling bearing according to a second embodiment of a second invention. The difference between the second embodiment and the first embodiment lies only in that an axially straight knurling portion 58 is provided on the outer peripheral surface of the outer ring 41 instead of a diamond knurling portion 58. That is, the difference is that the knurling portion 58 on the outer peripheral surface of the outer ring 41 is a diamond knurling portion 58 in which a plurality of V-shaped grooves 57a in a first direction extending obliquely with respect to the axis and a plurality of V-shaped grooves 57b in a second direction extending in a direction different from the extending direction of the V-shaped grooves 57a in the first direction intersect each other in the first embodiment. In contrast, in the second embodiment, it is an axially straight knurling portion 58 composed of a plurality of V-shaped grooves 57 extending in the axial direction, and the structures other than this are the same. Therefore, the parts corresponding to the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

[0244] As Figure 13 , Figure 15 shown, the V-shaped grooves 57 of the axially straight knurling portion 58 are formed to be arranged in parallel in the axial direction at a constant pitch. Chamfering is performed on the entire circumference at both axial ends of the outer peripheral surface of the outer ring 41. The pitch p (refer to Figure 13 ) of the V-shaped grooves 57 is all 0.628 to 1.571 mm, and the depth h (refer to Figure 14 ) of the V-shaped grooves 57 is all 0.264 to 0.652 mm. The V-shaped grooves 57 having this depth h are obtained by machining a straight knurling pattern of any one of the modules of m0.2, m0.3, and m0.5 described in Japanese Industrial Standards. A mountain portion 60 having a triangular cross-section that separates the V-shaped grooves 57 from each other is formed between adjacent V-shaped grooves 57.

[0245] As Figure 14 shown, the insulating resin layer 44 is formed to have a thickness t of 0.8 mm or more (preferably 1.0 mm or more) and 2.0 mm or less at the top of the mountain portion 60. That is, the insulating resin layer 44 is formed such that the minimum thickness of the insulating resin layer 44 on the outer peripheral surface of the outer ring 41 is 0.8 mm or more (preferably 1.0 mm or more). The angle formed by the two inclined surfaces of the V-shaped groove 57 is set to be 88° or more and 92° or less (for example, 90°).

[0246] As Figure 15 shown, for the insulating rolling bearing of this second embodiment, the knurling portion 58 into which the resin for forming the insulating resin layer 44 enters is composed of a plurality of V-shaped grooves 57 extending in the axial direction. The extending direction of the V-shaped grooves 57 constituting the knurling portion 58 is the axial direction, that is, a direction perpendicular to the circumferential direction. Therefore, the circumferential offset between the insulating resin layer 44 and the outer ring 41 can be reliably prevented, and the creep of the insulating resin layer 44 on the outer ring side can be particularly effectively prevented. In addition, it has the same effects as the first embodiment.

[0247] Figures 16 to 18 An insulating rolling bearing according to a third embodiment of the second invention. The difference between the third embodiment and the first embodiment is only that a circumferential straight knurl processing portion 58 is provided on the outer peripheral surface of the outer ring 41 instead of the diamond knurl processing portion 58. That is, the difference is that the knurl processing portion 58 on the outer peripheral surface of the outer ring 41 is a diamond knurl processing portion 58 in which a plurality of V-shaped grooves 57a in a first direction extending obliquely with respect to the axial direction and a plurality of V-shaped grooves 57b in a second direction extending in a direction different from the extending direction of the V-shaped grooves 57a in the first direction intersect each other in the first embodiment. In contrast, in the third embodiment, it is a circumferential straight knurl processing portion 58 composed of a plurality of V-shaped grooves 57 extending in the circumferential direction, and the other structures are the same. Therefore, the parts corresponding to the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

[0248] As Figure 16 , Figure 18 shown, the V-shaped grooves 57 of the circumferential straight knurl processing portion 58 are formed to be arranged in parallel in the circumferential direction at a constant pitch. Chamfering is performed on the entire circumference at both axial ends of the outer peripheral surface of the outer ring 41. The pitch p (refer to Figure 16 ) of the V-shaped grooves 57 is 0.628 to 1.571 mm, and the depth h (refer to Figure 17 ) of the V-shaped grooves 57 is 0.264 to 0.652 mm. The V-shaped grooves 57 having the depth h are obtained by processing a straight knurl of any one of the modules of m0.2, m0.3, and m0.5 described in Japanese Industrial Standards. A mountain portion 60 having a triangular cross section for separating the V-shaped grooves 57 from each other is formed between adjacent V-shaped grooves 57.

[0249] As Figure 17 shown, the insulating resin layer 44 is formed to have a thickness t of 0.8 mm or more (preferably 1.0 mm or more) and 2.0 mm or less at the position of the top of the mountain portion 60. That is, the insulating resin layer 44 is formed such that the minimum thickness of the insulating resin layer 44 on the outer peripheral surface of the outer ring 41 is 0.8 mm or more (preferably 1.0 mm or more). The angle formed by the two inclined surfaces of the V-shaped groove 57 is set to be 88° or more and 92° or less (90° in the figure).

[0250] As Figure 18As shown, for the insulated rolling bearing of this third embodiment, the knurled portion 58 for the resin forming the insulating resin layer 44 is composed of a plurality of V-shaped grooves 57 extending in the circumferential direction. The extending direction of the V-shaped grooves 57 constituting the knurled portion 58 is the circumferential direction, that is, the direction perpendicular to the axial direction. Therefore, axial displacement between the insulating resin layer 44 and the outer ring 41 can be reliably prevented, and particularly effectively prevent the peeling of the insulating resin layer 44 on the outer ring side from the outer ring width surface 46. In addition, it has the same effects as the first embodiment.

[0251] Figures 19 to 21 The figure shows an insulated rolling bearing according to the fourth embodiment of the second invention. Compared with the first embodiment, the difference in the fourth embodiment is that the knurled portion 58 is provided only on a part of the axial direction of the outer peripheral surface of the outer ring 41 instead of the entire outer peripheral surface of the outer ring 41, and the other part of the outer peripheral surface of the outer ring 41 is a cylindrical surface 62. The structures other than this are the same. Therefore, parts corresponding to the first embodiment are marked with the same reference numerals and the description is omitted.

[0252] As Figure 19 、 Figure 21 shown, the knurled portion 58 is an axial straight knurled portion 58 composed of a plurality of V-shaped grooves 57 extending in the axial direction. The V-shaped grooves 57 of the axial straight knurled portion 58 are formed to be arranged in parallel in the axial direction at a constant pitch. Chamfering is performed on the entire circumference at both axial ends of the outer peripheral surface of the outer ring 41. The pitch p (refer to Figure 19 ) of the V-shaped grooves 57 of the axial straight knurled portion 58 is all 0.628 - 1.571 mm, and the depth h (refer to Figure 20 ) of the V-shaped grooves 57 is all set to 0.264 - 0.652 mm. The V-shaped grooves 57 having this depth h are obtained by machining a straight knurled pattern of any one of the modules of m0.2, m0.3, and m0.5 described in Japanese Industrial Standards. As Figure 21 shown, a mountain portion 60 having a triangular cross-section for separating the V-shaped grooves 57 from each other is formed between adjacent V-shaped grooves 57.

[0253] As Figure 20 shown, the insulating resin layer 44 is formed to have a thickness t of 0.8 mm or more (preferably 1.0 mm or more) and 2.0 mm or less at the position of the top of the mountain portion 60. That is, the insulating resin layer 44 is formed such that the minimum thickness of the insulating resin layer 44 on the outer peripheral surface of the outer ring 41 is 0.8 mm or more (preferably 1.0 mm or more). The angle formed by the two inclined surfaces of the V-shaped groove 57 is set to be 88° or more and 92° or less (90° in the figure).

[0254] As Figure 21As shown, the outer circumferential surface of the outer ring 41 is provided with a knurled portion 58 only in a part in the axial direction, and the other parts are not provided with the knurled portion 58 and are formed as a cylindrical surface 62. That is, on the outer circumferential surface of the outer ring 41, a cylindrical surface 62 on one side in the axial direction, a knurled portion 58, and a cylindrical surface 62 on the other side in the axial direction are formed adjacent to each other in the axial direction. A step 63 extending in the circumferential direction is formed between the knurled portion 58 and the cylindrical surface 62 on one side in the axial direction, and a step 64 extending in the circumferential direction is also formed between the knurled portion 58 and the cylindrical surface 62 on the other side in the axial direction. The step 63 and the step 64 are formed to face each other in the axial direction with the knurled portion 58 interposed therebetween. The step 63 is a portion that stands radially outward from the V-shaped groove 57 side toward the cylindrical surface 62 side, and connects the inner surface of the V-shaped groove 57 and the cylindrical surface 62. Similarly, the step 64 is also a portion that stands radially outward from the V-shaped groove 57 side toward the cylindrical surface 62 side, and connects the inner surface of the V-shaped groove 57 and the cylindrical surface 62.

[0255] For the insulating rolling bearing of the fourth embodiment, a part in the axial direction of the outer circumferential surface of the outer ring 41 is formed as the cylindrical surface 62, so that grinding processing of the outer ring raceway groove 47 (refer to Figure 20 ) and the outer ring width surface 46 and the like can be carried out with high precision based on the cylindrical surface 62.

[0256] In addition, for the insulating rolling bearing of the fourth embodiment, steps 63 and 64 extending in the circumferential direction are formed to face each other on both sides in the axial direction of the knurled portion 58, so that the offset between the insulating resin layer 44 and the outer ring 41 toward both sides in the axial direction can be reliably prevented. This is because a part of the resin forming the insulating resin layer 44 is clamped by the steps 63 and 64 extending in the circumferential direction of the knurled portion 58, and thus the movement of the insulating resin layer 44 toward both sides in the axial direction is restricted. In addition, it has the same effects as the first embodiment.

[0257] Here, it may also be that on the outer circumferential surface of the outer ring 41, only the knurled portion 58 and the cylindrical surface 62 on one side in the axial direction are formed adjacent to each other in the axial direction, and the cylindrical surface 62 on the other side in the axial direction is not formed. In this case, a step 63 extending in the circumferential direction is formed between the knurled portion 58 and the cylindrical surface 62 on one side in the axial direction. Even for the insulating rolling bearing of this embodiment, grinding processing of the outer ring raceway groove 47 (refer to Figure 20 ) and the outer ring width surface 46 and the like can be carried out with high precision based on the cylindrical surface 62. In addition, the offset between the insulating resin layer 44 and the outer ring 41 toward one side in the axial direction can be reliably prevented.

[0258] In each of the embodiments of the second invention described above, the case where the insulating resin layer 44 is formed on the outer ring 41 and the outer ring width surface 46 has been described, but it may also be formed on the inner ring 42 and the inner ring width surface 50. That is, a knurling portion 58 for allowing the resin for forming the insulating resin layer 44 to enter may be provided on the inner circumferential surface of the inner ring 42, and the insulating resin layer 44 may be continuously formed on the entire inner circumferential surface of the inner ring 42 and the inner ring width surface 50. Further, the insulating resin layer 44 may be formed on the inner ring 42 and the inner ring width surface 50 while being formed on the outer ring 41 and the outer ring width surface 46. In addition, the knurling portion 58 in the fourth embodiment may be diamond knurling or circumferential straight knurling. Further, in each of the above embodiments, a ball bearing in which the rolling elements 43 are balls has been described, but the second invention can also be applied to a roller bearing in which the rolling elements 43 are rollers.

[0259] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is shown by the scope of claims of this application rather than by the above description, and is intended to include the meanings equivalent to the scope of claims of this application and all modifications within the scope.

Claims

1. An insulating rolling bearing, comprising: Outer ring (1); An inner ring (2) is arranged radially inward of the outer ring (1); A plurality of rolling elements (3) are assembled between the outer ring (1) and the inner ring (2); and An insulating molded resin (5) covers the outer periphery of the outer ring (1) and the axial end faces (6) on both sides of the outer ring (1). Annular molded recesses (8) are formed at both axial ends of the inner circumference of the outer ring (1), and the molded recesses (8) are open to the axial end surface (6) of the outer ring (1) and extend in the circumferential direction. The molded resin (5) comprises: 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 radial inner end of the end face insulating portion (5b) and entering into the molded recess (8), wherein at least a portion of the recess side surface (13) of the molded recess (8) facing the axial outer side is covered by the end inner peripheral insulating portion (5c). The insulating rolling bearing is characterized in that A portion of the recessed portion side surface (13) covered by the end inner peripheral insulating portion (5c) is formed as an inclined surface that is inclined toward the radial inner side and displaced toward the axial outer side.

2. The insulating rolling bearing according to claim 1, characterized in that: The inclined surface is an annular truncated cone surface that forms an angle (θ) of 87° or less with respect to the axial direction.

3. The insulating rolling bearing according to claim 1 or 2, characterized in that: The recessed side surface (13) comprises: a molded portion (15) covered by the end inner peripheral insulating portion (5c); and a non-molded portion (16) not covered by the end inner peripheral insulating portion (5c) and exposing the surface of the outer ring (1). The radial height dimension (H) of the non-molded portion (16) is set to be greater than 1.0 mm.

4. The insulating rolling bearing according to claim 3, characterized in that: The non-molded portion (16) is formed as an annular plane perpendicular to the axial direction.

5. The insulating rolling bearing according to any one of claims 1 to 4, characterized in that: An axial distance (W) from the side surface (13) of the recess to the surface of the end face insulating portion (5b) is set to be greater than 2.25 mm.

6. The insulating rolling bearing according to any one of claims 1 to 5, characterized in that: A relief groove (18) is formed on a recessed bottom surface (14) of the mold recessed portion (8) facing radially inward, and the relief groove (18) extends in the circumferential direction in a cross-sectional shape recessed radially outward.

7. An insulating rolling bearing, comprising: Outer ring (1); An inner ring (2) is arranged radially inward of the outer ring (1); A plurality of rolling elements (3) are assembled between the outer ring (1) and the inner ring (2); and An insulating molded resin (5) covers the inner circumference of the inner ring (2) and the axial end faces (10) on both sides of the inner ring (2). Annular molded recesses (8) are formed at both axial ends of the outer circumference of the inner ring (2). The molded recesses (8) are open to the axial end faces (10) of the inner ring (2) and extend in the circumferential direction. The molded resin (5) comprises: an inner peripheral insulating portion (5d) covering the inner periphery of the inner ring (2); an end face insulating portion (5e) covering the axial end face (10) of the inner ring (2); and an end peripheral insulating portion (5f) extending axially inward from the radial outer end of the end face insulating portion (5e) and entering into the molded recess (8), wherein at least a portion of the recess side surface of the molded recess (8) facing the axial outer side is covered by the end peripheral insulating portion (5f). The insulating rolling bearing is characterized in that A portion of the recessed portion side surface covered by the end peripheral insulating portion (5f) is formed as 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, characterized in that: The inclined surface is an annular truncated cone surface that forms an angle of 87° or less with respect to the axial direction.

9. The insulating rolling bearing according to claim 7 or 8, characterized in that: The side surface of the recess has: a molded portion, which is covered by the end peripheral insulating portion (5f); and a non-molded portion, which is not covered by the end peripheral insulating portion (5f) and exposes the surface of the inner ring (2). The height dimension of the non-mold portion in the radial direction is set to be 1.0 mm or more.

10. The insulating rolling bearing according to claim 9, characterized in that: The non-molded portion is formed as an annular plane perpendicular to the axial direction.

11. The insulating rolling bearing according to any one of claims 7 to 10, characterized in that: The axial distance from the side surface of the recess to the surface of the end face insulating portion (5e) is set to be greater than 2.25 mm.

12. The insulating rolling bearing according to any one of claims 7 to 11, characterized in that: A relief groove is formed on the bottom surface of the molded recess (8) facing radially outward, and the relief groove extends in the circumferential direction in a cross-sectional shape recessed radially inward.

13. An insulating rolling bearing, comprising: Outer ring (41); An inner ring (42) is arranged radially inward of the outer ring (41); A plurality of rolling elements (43) are assembled between the outer ring (41) and the inner ring (42); and at least one of an insulating resin layer (44) continuously formed on the entire outer circumference of the outer ring (41) and the outer ring width (46) on both axial sides of the outer ring (41) and an insulating resin layer (44) continuously formed on the entire inner circumference of the inner ring (42) and the inner ring width (50) on both axial sides of the inner ring (42), The insulating rolling bearing is characterized in that A knurled portion (58) is provided on the surface forming the insulating resin layer (44) in the outer circumferential surface of the outer ring (41) and the inner circumferential surface of the inner ring (42). The knurled portion (58) allows the resin forming the insulating resin layer (44) to enter and is composed of a plurality of V-shaped grooves (57) arranged in parallel at a constant interval.

14. The insulating rolling bearing according to claim 13, characterized in that: The knurled portion (58) is a reticulated knurled portion (58) having a plurality of V-grooves (57a) extending in a first direction obliquely relative to an axial direction and a plurality of V-grooves (57b) extending in a second direction in a direction different from the direction in which the V-grooves (57a) in the first direction extend, and the V-grooves (57a) in the first direction and the V-grooves (57b) in the second direction intersect with each other.

15. The insulating rolling bearing according to claim 13, characterized in that: The knurled portion (58) is an axial straight knurled portion (58) composed of a plurality of V-shaped grooves (57) extending in the axial direction.

16. The insulating rolling bearing according to claim 13, characterized in that: The knurled portion (58) is a circumferential straight knurled portion (58) composed of a plurality of V-shaped grooves (57) extending in the circumferential direction.

17. The insulating rolling bearing according to any one of claims 13 to 16, characterized in that: The knurled portion (58) is provided on the entire surface of the outer peripheral surface of the outer ring (41) and the inner peripheral surface of the inner ring (42) where the insulating resin layer (44) is formed.

18. The insulating rolling bearing according to any one of claims 13 to 16, characterized in that: The knurled portion (58) is only provided on an axial portion of the surface forming the insulating resin layer (44) in the outer circumferential surface of the outer ring (41) and the inner circumferential surface of the inner ring (42), and the other portions of the surface are not provided with the knurled portion (58) and are formed as a cylindrical surface (62).

19. The insulating rolling bearing according to any one of claims 13 to 18, characterized in that: The outer ring surface (46) and the inner ring surface (50) are flat surfaces without grooves.

20. The insulating rolling bearing according to any one of claims 13 to 19, characterized in that: The pitch (p) of the V-shaped groove (57) of the knurled portion (58) is 0.628 to 1.571 mm, and the depth (h) of the V-shaped groove (57) of the knurled portion (58) is 0.264 to 0.652 mm.

21. The insulating rolling bearing according to any one of claims 13 to 20, characterized in that: A mountain portion (60) having a triangular cross-section is formed between adjacent V-shaped grooves (57) to separate the V-shaped grooves (57) from each other. The thickness (t) of the insulating resin layer (44) at the top of the mountain portion (60) is greater than or equal to 0.8 mm and less than or equal to 2.0 mm.

22. The insulating rolling bearing according to any one of claims 13 to 21, characterized in that: The insulating resin layer (44) is formed of a resin having a molding shrinkage rate of 0.2% or more.

23. The insulating rolling bearing according to any one of claims 13 to 22, characterized in that: The insulating resin layer (44) has a 1.0×10 -5 / ℃ or above, and has a linear expansion coefficient of 2.0×10 -5 / ℃ or above linear expansion coefficient.

24. The insulating rolling bearing according to any one of claims 13 to 23, characterized in that: The insulating resin layer (44) is formed of a resin having a dielectric breakdown strength of 1 kV / mm or more.

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