JP2019138467A - Electric corrosion bearing - Google Patents

Abstract

To provide an electric corrosion bearing which inhibits electric corrosion of a bearing ring with an insulation material and makes the insulation material less likely to be peeled from the bearing ring.SOLUTION: An electric corrosion bearing 10 includes: an inner ring 11; an outer ring 12; multiple balls 13 provided between the inner ring 11 and the outer ring 12; and an annular electric corrosion prevention member 20 which is attached to the outer ring 12 and covers at least an outer peripheral surface 15 of the outer ring 12. The electric corrosion prevention member 20 has: an insulation material 22 which covers the outer peripheral surface 15, is fixed to the outer peripheral surface 15, and is made of rubber or resin; and a cover 21 which covers the insulation material 22 and is fixed to the insulation material 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric corrosion prevention bearing.

  For example, in a rolling bearing used in an electric device such as a motor, a potential difference may occur between the inner ring and the outer ring. When a potential difference is generated, current flows through the rolling bearing through the rolling elements, and thus there is a possibility that electrolytic corrosion occurs on the races of the inner ring and the outer ring. When electrolytic corrosion occurs on the raceway, abnormal noise is generated during rotation, or the location of the electrolytic corrosion occurs as a starting point, causing the raceway to peel off and reducing the bearing life.

  In order to prevent electrolytic corrosion, there is a means in which the rolling element is ceramic. However, in this case, the cost becomes high. Thus, a rolling bearing in which an insulating material is provided on the outer periphery of the outer ring has been proposed (see, for example, Patent Document 1).

JP 2008-39032 A

  In the case of the electric corrosion prevention bearing disclosed in Patent Document 1, it is preferable that the insulating material is thin in order not to lower the rigidity of the bearing. However, when the insulating material is thin, when the electric corrosion prevention bearing is attached to the housing of an electric device or the like, the insulating material may be caught on the housing, for example, and a part may be peeled off. Even if a part of the insulating material is peeled off, the insulation becomes insufficient, and there is a possibility that electrolytic corrosion occurs on the races of the inner ring and the outer ring.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrolytic corrosion prevention bearing that suppresses electric corrosion of a bearing ring with an insulating material and makes the insulating material difficult to peel off from the bearing ring.

  The electric corrosion prevention bearing of the present invention is attached to one of the inner ring, the outer ring, a plurality of rolling elements provided between the inner ring and the outer ring, and one of the inner ring and the outer ring. A rubber or resin insulating material that includes an annular electrolytic corrosion prevention member that covers at least the cylindrical circumferential surface of the raceway, and the electrolytic corrosion prevention member covers the circumferential surface and is fixed to the circumferential surface. And a cover that covers the insulating material and is fixed to the insulating material.

  In this electric corrosion prevention bearing, an insulating material made of rubber or resin is fixed to the bearing ring and the cover, and the insulating material and the cover are integrated with the bearing ring. Since the insulating material is covered with the cover, for example, when the electric corrosion prevention bearing is attached to the mating member, the insulating material can be prevented from being peeled off due to being caught by the mating member. The race is attached to the mating member via an insulating material and a cover. Since the insulating material is interposed between the mating member and the race, the electrolytic corrosion of the race can be suppressed.

  Preferably, a groove into which a part of the insulating material enters is formed on the peripheral surface. In this case, since a part of the insulating material enters a groove formed on the peripheral surface of the raceway ring, the insulation material is more difficult to peel off from the raceway ring.

Preferably, the groove is a knurled groove formed along the circumferential direction. In this case, a part of the insulating material enters the knurled groove, and the insulating material is more difficult to peel off from the raceway.
More preferably, the circumferential surface is formed with the knurled groove and a circumferential groove which is provided on both sides in the axial direction of the knurled groove and is recessed in the radial direction from the convex portion of the knurled groove, A part of the insulating material enters the knurled groove and the circumferential groove. In this case, when a part of the insulating material enters the circumferential groove, the fixing strength of the insulating material with respect to the raceway is increased. In particular, the fixing strength in the axial direction is increased.

  Except when the groove is a knurled groove, preferably, the groove is an annular groove formed along a circumferential direction, and the central axis of the annular groove is eccentric with respect to the central axis of the peripheral surface. Yes. In this case, a configuration is obtained in which the groove depth of the annular groove gradually changes along the circumferential direction. For this reason, even if the insulating material tries to rotate in the circumferential direction, this rotation is restricted by the portion of the insulating material that enters the annular groove.

  More preferably, on the peripheral surface, the first region where the groove is formed has a rougher surface than the second region other than the groove. In this case, in the first region, the adhesion strength between the groove and the insulating material entering the groove is increased. Therefore, the fixing strength of the insulating material with respect to the raceway is increased. On the other hand, in the second area, the dimensional accuracy is higher than in the first area. Therefore, the accuracy of attaching the insulating material and the cover to the raceway is increased by using the second region as a reference.

  Preferably, the cover includes a cylindrical first cover portion positioned on the axially central side, and a cylindrical second cover positioned on one side in the axial direction and closer to the circumferential surface than the first cover portion. Part. In this case, the cover has a stepped shape with different diameters between the first cover part and the second cover part. When installing the electric corrosion prevention bearing close to the mating member from one side in the axial direction, the gap formed between the second cover part on the one side in the axial direction and the mating member becomes large, so that mounting is easy. Become.

  Preferably, the groove is provided over the entire circumference in a central region in the axial direction of the raceway. In this case, the effect | action which prevents the peeling by the shear in an axial direction between the insulating material of an electrolytic corrosion prevention member and a bearing ring becomes high.

  Preferably, the insulating material is acrylic rubber. In this case, the friction coefficient between the insulating material and the race is relatively large. Therefore, the fixing strength of the insulating material with respect to the raceway is increased.

  In addition to acrylic rubber, the insulating material may be nitrile rubber. When the insulating material is made of rubber, the insulating material is fixed to the raceway ring and the cover by vulcanization molding with raw rubber (raw rubber) interposed between the raceway ring and the cover. However, if the vulcanization temperature is high, the race may be softened. Therefore, the insulating material is preferably nitrile rubber. In this case, the vulcanization temperature can be made relatively low and softening of the raceway can be prevented.

In order to increase the fixing strength between the bearing ring and the insulating material, it is preferable to interpose an adhesive layer between them. However, in order to provide an adhesive layer between the bearing ring and the insulating material, a coating treatment may be performed as a pretreatment on the entire bearing ring. In this case, the coating treatment is performed up to the track where the rolling elements are in rolling contact. For this reason, finally, it is necessary to perform a finishing process (polishing process, super-finishing process) on the raceway of the bearing ring to which the insulating material is fixed. However, since the reference for performing the finishing process is on the insulating material side having low rigidity, the processing accuracy may be reduced. Therefore, in order to eliminate the need for such finishing, the following configuration is preferable. That is, it is preferable that the cover covers the insulating material via an adhesive layer, and the insulating material directly covers the raceway. In this case, the insulating material may be fixed to the raceway after finishing the raceway of the raceway.
Moreover, according to the said structure, an adhesive bond layer exists between a cover and an insulating material, and the fixed strength between these can be raised. In contrast, no adhesive layer is interposed between the insulating material and the raceway, and the insulation material directly covers the raceway. The fixing strength cannot be increased by the adhesive layer between the insulating material and the raceway, but when the electrolytic corrosion preventing bearing has a configuration in which a part of the insulating material enters the groove as described above, or When the insulating material is a member having a large friction coefficient, such as acrylic rubber, the fixing strength between the insulating material and the race is ensured.

  According to the electric corrosion prevention bearing of the present invention, the electric corrosion of the bearing ring is suppressed by the insulating material, and the insulating material is hardly peeled off from the bearing ring. As a result, it is possible to prevent the electrolytic corrosion preventing member from falling off during conveyance of the electrolytic corrosion preventing bearing, and to simplify the work of attaching the electrolytic corrosion preventing member to the counterpart member (for example, the housing).

It is sectional drawing which shows an example of an electrolytic corrosion prevention bearing. It is sectional drawing for demonstrating mainly an outer ring | wheel and an electrolytic corrosion prevention member. It is sectional drawing which shows a part of modification of an electrolytic corrosion prevention bearing. It is explanatory drawing explaining another modification of an electric corrosion prevention bearing. It is a figure for demonstrating another modification, and is the explanatory view which looked at the outer ring from the axial direction. It is sectional drawing of an outer ring | wheel. It is a figure for demonstrating another modification, and is sectional drawing which mainly shows an outer ring | wheel and an electrolytic corrosion prevention member. It is a side view which shows a part of outer ring. It is explanatory drawing which looked at a part of knurled groove | channel from the axial direction. It is a figure for demonstrating another modification, and is sectional drawing which mainly shows an outer ring | wheel and an electrolytic corrosion prevention member.

[Entire structure of electric corrosion prevention bearing]
FIG. 1 is a cross-sectional view illustrating an example of an electrolytic corrosion preventing bearing. The electric corrosion prevention bearing 10 (hereinafter also simply referred to as “bearing 10”) includes an inner ring 11, an outer ring 12, and a plurality of rolling elements 13 provided between the inner ring 11 and the outer ring 12. . The bearing 10 shown in FIG. 1 is a ball bearing, and the rolling element is a ball 13. The bearing 10 includes an annular cage 14. The cage 14 holds a plurality of balls 13 at intervals along the circumferential direction.

  The bearing 10 is attached to a housing 9, and in the present embodiment, supports a shaft (rotary shaft) 6 provided in the housing 9 of the motor. The housing 9 and the shaft 6 are indicated by an imaginary line (two-dot chain line). The bearing 10 is attached to the housing 9 by bringing the bearing 10 close to the housing 9 in the axial direction (from the left side in FIG. 1) and pressing the bearing 10 in the axial direction.

  The bearing 10 includes an electrolytic corrosion preventing member 20. The electrolytic corrosion preventing member 20 is annular and attached to the outer ring 12. The electrolytic corrosion preventing member 20 has a rubber insulating material 22. The insulating material 22 prevents the outer ring 12 and the housing 9 from coming into metal contact, and prevents a potential difference from occurring between the outer ring 12 and the inner ring 11. The electrolytic corrosion preventing member 20 shown in FIG. 1 covers the outer peripheral surface 15 of the outer ring 12 as well as the side surface 16 that is an annular shape on one axial side of the outer ring 12. A specific configuration of the electrolytic corrosion preventing member 20 will be described later. The insulating material 22 may be made of resin in addition to rubber. In the embodiment described below, the insulating material 22 is made of rubber.

  The inner ring 11 is a cylindrical member that is externally fitted to the shaft 6, and a track (inner ring track) 31 is formed on the outer peripheral surface. The outer ring 12 is a cylindrical member attached to the housing 9 via the electrolytic corrosion preventing member 20, and a track (outer ring track) 32 is formed on the inner peripheral surface. The inner ring 11, the outer ring 12, and the ball 13 are made of steel such as bearing steel. The cage 14 may be made of metal, but is made of resin in the present embodiment.

[About the electric corrosion prevention member 20]
FIG. 2 is a cross-sectional view for mainly explaining the outer ring 12 and the electrolytic corrosion preventing member 20. The electrolytic corrosion preventing member 20 includes an insulating material 22 and a cover 21. The insulating material 22 is made of rubber. Insulating material 22 of this embodiment is nitrile rubber. The cover 21 is made of metal. The cover 21 of this embodiment is made of a steel plate. The insulating material 22 may be acrylic rubber as will be described later.

  The insulating material 22 has a cylindrical portion 23 that covers the outer peripheral surface 15 of the outer ring 12, an annular portion 24 that covers the side surface 16 of the outer ring 12, and a connecting portion 25 that connects the cylindrical portion 23 and the annular portion 24. doing. The connecting portion 25 covers the convex rounded surface 18 formed on the outer ring 12. The cover 21 includes a cylindrical first covering portion 26 that covers the cylindrical portion 23, an annular second covering portion 27 that covers the annular portion 24, and the first covering portion 26 and the second covering portion 27. It has the 3rd coating | coated part 28 to connect. The third covering portion 28 covers the connecting portion 25.

  The outer ring 12 and the insulating material 22 are bonded. In the case of this embodiment, the outer ring 12 and the insulating material 22 are vulcanized and bonded. The cover 21 and the insulating material 22 are bonded. In the present embodiment, the cover 21 and the insulating material 22 are vulcanized and bonded, and an adhesive layer 29 is interposed between the cover 21 and the insulating material 22. Since the adhesive layer 29 is formed, the cover 21 is subjected to surface cleaning, coating treatment, and adhesive application before vulcanization molding. As described above, the outer ring 12 and the insulating material 22 are fixed, and the cover 21 and the insulating material 22 are fixed. In order to obtain this configuration, in this embodiment, the raw rubber (raw rubber) of the insulating material 22 is interposed between the outer ring 12 and the cover 21 and vulcanized. Thereby, the insulating material 22 is fixed to the outer ring 12 and the cover 21. In the bearing 10 of the present embodiment, the cover 21 covers the insulating material 22 via the adhesive layer 29, whereas the insulating material 22 directly covers the outer ring 12 (without the adhesive layer 29). doing.

  The thickness t1 of the cover 21 is thin, for example, set in a range of 0.3 millimeters to 1.5 millimeters. The cover 21 is manufactured by press-molding a steel plate or the like, and the thickness t1 is (substantially) the same over the entire range. In the present embodiment, the insulating material 22 is thinner than the cover 21 (t2 <t1). The thickness t2 of the insulating material 22 (excluding the connecting portion 25) is set, for example, in the range of 0.15 millimeters to 0.5 millimeters. The thickness t2 of the insulating material 22 is (substantially) the same except for the connecting portion 25. The thickness t2 of the insulating material 22 is preferably a minimum thickness that allows the insulating material 22, the outer ring 12, and the cover 21 to be integrally formed (the vulcanization molding). That is, the thickness t2 of the insulating material 22 is made as thin as possible. Note that the insulating material 22 may have the same thickness as the cover 21 (t2 = t1). When the cover 21 is particularly thin, the insulating material 22 may be thicker than the cover 21 (t2> t1).

  In the present embodiment, a groove 17 is formed on the outer peripheral surface 15 of the outer ring 12. The groove 17 is provided in the central region in the axial direction of the outer ring 12 over the entire circumference. The cross-sectional shape of the groove 17 is a concave arc shape. The cross-sectional shape of the groove 17 may be other shapes, and may be a rectangle or a V shape. The depth of the groove 17 is set in a range of, for example, 0.3 millimeter to 1 millimeter. As described above, the insulating material 22 is sandwiched between the outer ring 12 and the cover 21 and vulcanized. At this time, a part 30 of the insulating material 22 enters the groove 17 and is molded. For this reason, in the completed electric corrosion prevention bearing 10, a part 30 of the insulating material 22 enters the groove 17. A part 30 of the insulating material 22 is also vulcanized and bonded to the groove 17. That is, a part 30 of the insulating material 22 enters the groove 17 and is fixed (vulcanized and bonded).

  The bearing 10 of this embodiment is attached to the inner peripheral surface 9b of the housing 9 in an interference fit state. That is, the outer ring 12 having the electrolytic corrosion preventing member 20 is press-fitted into the inner peripheral surface 9 b of the housing 9. Thereby, creep of the outer ring 12 (slip in the circumferential direction of the outer ring 12 with respect to the housing 9) is suppressed. For this purpose, the bearing 10 is attached to the housing 9 by bringing the bearing 10 close to the housing 9 (from the left side in FIG. 1) in the axial direction and pressing the bearing 10 in the axial direction as described above. Is called.

  Since the outer ring 12 having the electrolytic corrosion preventing member 20 is pressed into the inner peripheral surface 9b of the housing 9, it is preferable that the dimensional accuracy of the outer peripheral surface 21a of the cover 21 is high. Therefore, the outer peripheral surface 21 a of the cover 21 may be polished while the electrolytic corrosion preventing member 20 is fixed to the outer ring 12. That is, the outer peripheral surface 21a may be a polished surface. Since the outer peripheral surface 21a is a polished surface, the fastening allowance of the outer ring 12 with respect to the housing 9 via the electrolytic corrosion preventing member 20 tends to be constant.

  Thus, since the outer peripheral surface 21a of the cover 21 may be polished in a state where the electrolytic corrosion preventing member 20 is fixed to the outer ring 12, the insulating material 22 is preferably as thin as possible. The bearing 10 having the outer ring 12 attached to the housing 9 via the electrolytic corrosion preventing member 20 preferably has as high rigidity as possible in order to support the shaft 6. For this reason, the insulating material 22 is preferably as thin as possible. The thickness t2 of the insulating material 22 is preferably 0.5 millimeters or less.

  As described above, the electrolytic corrosion preventing bearing 10 includes the electrolytic corrosion preventing member 20 that covers the outer ring 12. The electrolytic corrosion preventing member 20 covers the outer peripheral surface 15 of the outer ring 12 and is fixed to the outer peripheral surface 15 with a rubber insulating material 22, and the cover 21 covers the insulating material 22 and is fixed to the insulating material 22. have. In the present embodiment, a groove 17 is formed on the outer peripheral surface 15 of the outer ring 12, and a part 30 of the insulating material 22 enters the groove 17.

  According to the electrolytic corrosion preventing bearing 10 having this configuration, the rubber insulating material 22 is fixed to the outer ring 12 and the cover 21, and the insulating material 22 and the cover 21 are integrated with the outer ring 12. Further, since a part 30 of the insulating material 22 enters the groove 17, the insulating material 22 is not easily peeled off from the outer ring 12. Furthermore, since the insulating material 22 is covered with the cover 21, when the bearing 10 is attached to the housing 9, it is possible to prevent the insulating material 22 from being peeled off by being caught on the housing 9. Further, according to the configuration, it is possible to prevent the electrolytic corrosion preventing member 20 from falling off the outer ring 12 even when the bearing 10 is conveyed. And the outer ring | wheel 12 will be in the state attached to the housing 9 via the insulating material 22 and the cover 21. FIG. Since the insulating material 22 is interposed between the housing 9 and the outer ring 12, electrolytic corrosion of the outer ring 12 (and the inner ring 11) can be suppressed.

  In order to increase the fixing strength between the outer ring 12 and the insulating material 22, it is preferable to interpose an adhesive layer between them. However, in order to provide an adhesive layer between the outer ring 12 and the insulating material 22, a film treatment may be performed as a pretreatment on the entire outer ring 12. In this case, since the coating process is performed up to the outer ring raceway 32, the insulating ring 22 and the cover 21 are finally fixed to the outer ring 12, and then the outer ring raceway 32 is finished (polished and superfinished). ) Is necessary. However, since the reference for performing this finishing process is on the insulating material 22 side having low rigidity, the processing accuracy may be reduced. Therefore, in order to eliminate the need for such finishing, in this embodiment, the cover 21 covers the insulating material 22 via the adhesive layer 29, but the insulating material 22 directly covers the outer ring 12. Yes. In this case, the insulating material 22 may be fixed to the outer ring 12 after finishing the outer ring raceway 32.

  According to this configuration, the adhesive layer 29 is interposed between the cover 21 and the insulating material 22, and the fixing strength between them can be increased. On the other hand, an adhesive layer is not interposed between the insulating material 22 and the outer ring 12, and the insulating material 22 directly covers the outer ring 12. The fixing strength cannot be increased between the insulating material 22 and the outer ring 12 by the adhesive layer. However, since a part 30 of the insulating material 22 enters the groove 17, the fixing strength between the insulating material 22 and the outer ring 12 is ensured.

  In this embodiment, the insulating material 22 is made of rubber. In this case, as described above, the insulating material 22 can be fixed to the outer ring 12 and the cover 21 by vulcanization molding with raw rubber (raw rubber) interposed between the outer ring 12 and the cover 21. However, if the vulcanization temperature is high and heating at a high temperature for a long time, the outer ring 12 may be softened. Therefore, the insulating material 22 is made of nitrile rubber. Thereby, it becomes possible to make a vulcanization temperature into comparatively low temperature, and softening of the outer ring | wheel 12 can be prevented.

  When the bearing 10 is pressed into the housing 9 and attached, an axial shearing force acts between the insulating material 22 of the electrolytic corrosion preventing member 20 and the outer ring 12. In the form shown in FIGS. 1 and 2, the groove 17 is provided over the entire circumference in the central region of the outer ring 12 in the axial direction. In this case, the effect | action which prevents the peeling by the shear in an axial direction between the insulating material 22 and the outer ring | wheel 12 becomes high. Therefore, when the bearing 10 is press-fitted into the housing 9 and attached, the outer ring 12 and the electrolytic corrosion preventing member 20 are kept integrated.

[Modification (Part 1)]
FIG. 3 is a cross-sectional view showing a part of a modified example of the bearing 10. In this bearing 10, the position of the groove 17 formed in the outer ring 12 is different from the bearing 10 shown in FIGS. As shown in FIG. 3, the groove 17 is formed on the outer peripheral surface 15 of the outer ring 12, not in the central region in the axial direction but in the side region in the axial direction. Although not shown, a plurality of grooves 17 may be formed. That is, the groove 17 may be formed in each of the center and side regions of the outer peripheral surface 15 of the outer ring 12. 1 to 3 are formed over the entire circumference of the outer peripheral surface 15, the grooves 17 may not be formed over the entire circumference. For example, the grooves 17 may be formed intermittently along the circumferential direction.

[Modification (Part 2)]
FIG. 4 is an explanatory view for explaining still another modified example. In FIG. 4, only the outer ring 12 is shown, and the electrolytic corrosion preventing member 20 is omitted. The grooves 17 of the respective forms shown in FIGS. 1 to 3 are formed along the circumferential direction. In the form shown in FIG. 4, a plurality of grooves 17 are formed on the outer peripheral surface 15 of the outer ring 12 along the axial direction (that is, the direction parallel to the central axis of the outer ring 12). And although not shown in figure, each insulating material 22 which the electrolytic corrosion prevention member 20 has enters in each groove | channel 17. As described above (see FIG. 2), when the outer peripheral surface 21 a of the cover 21 is polished, a circumferential shear force may act between the insulating material 22 of the electrolytic corrosion preventing member 20 and the outer ring 12. According to the groove | channel 17 shown in FIG. 4, the effect | action which prevents peeling by such a shearing force becomes high. The groove 17 shown in FIG. 4 has a groove wall surface 17a that is shorter than the axial length L1 of the flat surface portion 15a of the outer peripheral surface 15 and faces the axial direction on both sides of the groove longitudinal direction (axial direction). In this case, a part of the insulating material entering the groove 17 contacts the groove wall surface 17a. For this reason, it can also have the effect | action which prevents the peeling by the shear of an axial direction between the insulating material 22 of the electrolytic corrosion prevention member 20, and the outer ring | wheel 12.

  Although not shown, on the outer peripheral surface 15 of the outer ring 12, both a groove 17 along the axial direction as shown in FIG. 4 and a groove 17 along the circumferential direction as shown in FIG. 2 are formed. Also good. Further, not only the outer peripheral surface 15 of the outer ring 12 but also the side surface 16 of the outer ring 12 may be provided with a groove into which a part of the insulating material 22 of the electrolytic corrosion preventing member 20 enters.

[Modification (Part 3)]
FIG. 5 is a view for explaining still another modified example, and is an explanatory view of the outer ring 12 as viewed from the axial direction. In FIG. 5, the electrolytic corrosion preventing member 20 is indicated by an imaginary line (two-dot chain line). The form shown in FIG. 5 is the same as the form shown in FIGS. 2 and 3 except for the grooves 17. In the form shown in FIG. 5, a groove 17 into which a part of the insulating material 22 enters is formed in the outer ring 12 as in the form shown in FIGS. 1 and 2 and the form shown in FIG. 3. In FIG. 5, the groove 17 is shown deeper than actual in order to make the description of the groove 17 easier to understand. The groove 17 is an annular groove 17 c formed along the circumferential direction, and the annular groove 17 c is formed eccentrically with respect to the outer ring 12. That is, the central axis C1 of the outer peripheral surface 15 of the outer ring 12 and the central axis C2 of the annular groove 17c do not coincide with each other, and the central axis C2 of the annular groove 17c is aligned with the central axis C1 of the outer peripheral surface 15 of the outer ring 12. It is eccentric. In FIG. 5, the eccentricity of the central axes C1 and C2 is e. A specific example of the groove 17 (annular groove 17c) will be described. The depth (average value) of the groove 17 is 0.5 millimeter, and the eccentricity e is 0.3 millimeter. The eccentricity e is also shown larger than the actual amount for easy understanding.

  Since the annular groove 17c is formed eccentrically with respect to the outer ring 12, a structure in which the groove depth of the annular groove 17c gradually changes along the circumferential direction is obtained. For this reason, the thickness (thickness) of the part 30 of the insulating material 22 that has entered the annular groove 17c and continues in the circumferential direction changes along the circumferential direction. That is, there is a difference in the thickness (thickness) of the part 30 of the insulating material 22 that has entered the annular groove 17c and continues in the circumferential direction. Therefore, even if the insulating material 22 tries to rotate in the circumferential direction, the thickened portion of the part 30 of the insulating material 22 is clogged in the shallow portion of the annular groove 17c. Therefore, even if the insulating material 22 tries to rotate, the rotation is restricted by the part 30 that has entered the annular groove 17 c of the insulating material 22. According to the annular groove 17c that is eccentric with respect to the outer peripheral surface 15, the fixing strength in the axial direction of the insulating material 22 with respect to the outer ring 12 is increased, and the fixing strength in the circumferential direction is also increased.

  In the form shown in FIGS. 1 and 2 and the form shown in FIG. 3 in addition to the form shown in FIG. 5, the outer peripheral surface 15 of the outer ring 12 may be as follows. That is, on the outer peripheral surface 15 of the outer ring 12 (see FIG. 6), the first region K1 in which the groove 17 is formed has a rougher surface than the second region K2 other than the groove 17. The second region K2 is a region where the groove 17 is not formed. Specifically, in order to manufacture the outer ring 12, the outer peripheral surface 15 and the like are subjected to primary processing by turning, and then secondary processing is performed by polishing. The groove 17 is formed by primary processing. Although secondary processing is performed on the outer peripheral surface 15 in which the groove 17 is formed, the secondary processing is performed on a region other than the groove 17 (second region K2). For this reason, in the outer peripheral surface 15, the groove 17 (first region K1) is a turning surface, while the surface other than the groove 17 (second region K2) is a polished surface. Therefore, the surface of the first region K1 where the groove 17 is formed is rougher than the second region K2 other than the groove 17.

  With the configuration of the outer ring 12, in the first region K <b> 1, the adhesion strength between the groove 17 and the part 30 of the insulating material 22 entering the groove 17 is further increased. Therefore, the fixing strength of the insulating material 22 with respect to the outer ring 12 is increased. On the other hand, in the second region K2, the dimensional accuracy is higher than that of the first region K1. For forming the insulating material 22, vulcanization molding is performed as described above. At this time, it is necessary to position the cover 21 with respect to the outer ring 12. Therefore, the accuracy of attaching the insulating material 22 and the cover 21 to the outer ring 12 is increased by using the second region K2 with high dimensional accuracy as a reference.

[Modification (Part 4)]
FIG. 7 is a view for explaining still another modified example, and is a cross-sectional view mainly showing the outer ring 12 and the electrolytic corrosion preventing member 20. In the form shown in FIG. 7, the groove 17 formed in the outer peripheral surface 15 of the outer ring 12 is a knurled groove 17 b. FIG. 8 is a side view showing a part of the outer ring 12. FIG. 9 is an explanatory view of a part of the knurled groove 17b as seen from the axial direction. As shown in FIG. 9, the knurled groove 17b has a configuration in which convex portions 38 and concave portions 39 are alternately arranged along the circumferential direction. When the insulating material 22 enters the recess 39, the fixing strength of the insulating material 22 with respect to the outer ring 12 is increased. The knurled groove 17b increases the fixing strength in the axial direction, and particularly increases the fixing strength in the circumferential direction.

  The outer ring 12 is manufactured as follows. That is, the material is forged into an annular member having a predetermined shape, and the annular member is subjected to primary processing (grinding) and secondary processing (polishing) to obtain the outer ring 12. The knurled grooves 17b (and circumferential grooves 41 and 42 to be described later) are formed by knurling during the forging. The knurled grooves 17b (and the circumferential grooves 41 and 42) are not turned and polished after forming. For this reason, in the outer peripheral surface 15 of the outer ring 12, the area where the knurled grooves 17b (and the circumferential grooves 41 and 42) are formed is rougher than the area other than the knurled grooves 17b (and the circumferential grooves 41 and 42). .

  As shown in FIG. 8, the circumscribed circle diameter D1 of the convex portion 38 is smaller than the diameter D2 of the region (flat outer peripheral surface 37) in the outer peripheral surface 15 where the knurled grooves 17b are not formed (D1 <D2). ). In the case of knurling, the surface of the knurled groove 17b is rough, and, for example, there is a possibility that minute projections (deformed portions) that protrude further outward in the radial direction may be formed from the projections 38, although not shown. However, as described above, the knurled groove 17b is formed so as to satisfy the relationship of D1 <D2, so that even if the minute protrusion is formed, the knurled groove 17b and the cover 21 are too close to each other, It can prevent that the insulation by the insulating material 22 falls.

  As shown in FIGS. 7 and 8, the smooth outer surface is smaller in diameter than the flat outer peripheral surface 37 on the flat outer peripheral surface 37 side than the knurled groove 17 b and smaller in diameter than the circumscribed circle of the convex portion 38. One circumferential groove 41 is formed. Part of the insulating material 22 also enters the first circumferential groove 41. As shown in FIG. 7, a part 30 a of the insulating material 22 that has entered the first circumferential groove 41 is axially formed by a convex portion 38 of the knurled groove 17 b and a portion 40 having a flat outer circumferential surface 37 as an outer circumferential surface. Sandwiched. For this reason, the fixing strength about the axial direction of the insulating material 22 becomes still higher.

  Further, a smooth second circumferential groove 42 having a smaller diameter than the circumscribed circle of the convex portion 38 is formed on one axial side of the knurled groove 17b. A part 30 b of the insulating material 22 also enters the second circumferential groove 42. The portions 30a and 30b of the insulating material 22 that have entered the first circumferential groove 41 and the second circumferential groove 42 sandwich the knurled groove 17b from the axial direction. For this reason, the fixing strength about the axial direction of the insulating material 22 becomes still higher.

  The knurled groove 17b may be provided at the center in the axial direction on the outer peripheral surface 15, but as shown in FIG. 7, it is preferably provided on one side in the axial direction. This is because when the bearing 10 receives a radial load, the load is transmitted to and from the housing 9 not by the knurled groove 17b but by the portion 40 having the flat outer peripheral surface 37 as the outer peripheral surface. With this configuration, the bearing rigidity is increased, and a large radial load can be supported.

  Further, as described above, the outer circumferential surface 15 of the outer ring 12 is formed with the knurled groove 17b and the first circumferential groove 41 and the second circumferential groove 42 provided on both sides in the axial direction of the knurled groove 17b. Yes. Each of the first circumferential groove 41 and the second circumferential groove 42 is recessed inward in the radial direction from the tip of the convex portion 38 of the knurled groove 17b. A part of the insulating material 22 enters each of the knurled grooves 17b, the first circumferential grooves 41, and the second circumferential grooves 42. With this configuration, the fixing strength of the insulating material 22 in the axial direction is particularly increased.

[About the cover 21]
In the form shown in FIG. 7, the cover 21 has a stepped shape including portions having different outer diameters. That is, the cover 21 includes a cylindrical first cover part 46 and a cylindrical second cover part 47. The first cover part 46 is located on the axially central side. The second cover portion 47 is located on one side in the axial direction and closer to the outer peripheral surface 15 side than the first cover portion 46. That is, the second cover part 47 has a smaller outer diameter than the first cover part 46. According to this configuration, when the bearing 10 is attached to the housing 9 that is the counterpart member from one axial direction, the bearing 10 is disposed between the second cover portion 47 on the one axial side and the inner peripheral surface 9b of the housing 9. The gap formed in the is increased. For this reason, it becomes easy to press-fit the bearing 10 into the housing 9. About the point which the cover 21 has a stepped shape as mentioned above, it is applicable to the bearing 10 of each form shown in FIGS. 1-6, and the bearing 10 of the form of FIG. 10 mentioned later.

[Material of insulating material 22]
In each form of the bearing 10, the material of the insulating material 22 is made of rubber or resin. As described above, when the insulating material 22 is made of rubber, vulcanization molding is performed to fix the insulating material 22 to the outer ring 12 and the cover 21. In order to make the vulcanization temperature relatively low, the insulating material 22 is preferably nitrile rubber as described above. As another viewpoint, in order to improve the fixing strength between the insulating material 22 and the outer ring 12, the insulating material 22 is preferably acrylic rubber. When the insulating material 22 is acrylic rubber, the coefficient of friction against the metal surface of the outer ring 12 and the like is about 1.3 times higher than that of nitrile rubber. That is, when the insulating material 22 is acrylic rubber, the friction coefficient with respect to the outer ring 12 is relatively large. Therefore, the fixing strength of the insulating material 22 with respect to the outer ring 12 is increased.

[Modification (Part 5)]
In each of the embodiments, the groove 17 for allowing a part of the insulating material 22 to enter is formed on the outer peripheral surface 15 of the outer ring 12. However, the groove 17 may be omitted as shown in FIG. That is, the outer peripheral surface 15 may be a smooth outer peripheral surface. In this case, the insulating material 22 is preferably acrylic rubber. Thereby, even if the groove | channel 17 is abbreviate | omitted, the fixed intensity | strength of the insulating material 22 with respect to the outer ring | wheel 12 becomes high.

[Others]
In the bearing 10 of each of the above forms, the outer ring 12 contacts the stepped surface 9a of the housing 9 (see, for example, FIG. 1). For this reason, the insulating material 22 of the electrolytic corrosion preventing member 20 has an annular portion 24 that covers the side surface 16 of the outer ring 12, and the cover 21 has a second covering portion 27 that covers the annular portion 24. Although not shown, when the outer ring 12 contacts the inner peripheral surface 9b of the housing 9, but does not contact the stepped surface 9a of the housing 9, the annular portion 24 and the second covering portion 27 are omitted in the insulating material 22. Also good. That is, the electrolytic corrosion preventing member 20 may be an annular member that at least covers the cylindrical outer peripheral surface 15 of the outer ring 12.

  Although the case where the insulating material 22 is made of rubber has been described, it may be made of resin (thermoplastic resin). In this case, although not shown, the outer ring 12 and the cover 21 may be installed in the mold in a state where a gap is formed between the outer ring 12 and the cover 21, and the molten resin may be injection-molded into the gap. Thereby, the insulating material 22 made of resin covers the outer peripheral surface 15 of the outer ring 12 and is fixed to the outer peripheral surface 15. Moreover, the cover 21 covers the insulating material 22 and is fixed to the insulating material 22. In addition, a part of the insulating material 22 enters the groove 17 formed on the outer peripheral surface 15 of the outer ring 12.

  When the insulating material 22 is made of resin, if the gap formed between the outer ring 12 and the cover 21 is too narrow, the molten resin may not be sufficiently filled and injection molding may be difficult. On the other hand, if the insulating material 22 is made of rubber as in the above-described embodiment, vulcanization molding is possible even if the distance between the outer ring 12 and the cover 21 is narrow. In order to increase the rigidity of the bearing 10, it is preferable to make the insulating material 22 thinner. Moreover, the size of the bearing 10 can be made smaller if the insulating material 22 is made of rubber.

  In each of the above embodiments, the case where the electrolytic corrosion preventing member 20 is attached to the outer ring 12 has been described, but may be attached to the inner ring 11. That is, the electrolytic corrosion preventing member 20 is attached to one of the inner ring 11 and the outer ring 12 and has a configuration that covers at least the cylindrical peripheral surface of the ring. And when a groove | channel is formed in the surrounding surface of a bearing ring, a part of insulating material enters into a groove | channel.

The embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of rights of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope equivalent to the configurations described in the scope of claims.
In the embodiment, the case where the rolling element is the ball 13 (the bearing 10 is a ball bearing) has been described, but the rolling element may be a cylindrical roller, a tapered roller, or the like. The cage 14 can also be changed according to the rolling elements.

10: Electric corrosion prevention bearing 11: Inner ring 12: Outer ring 13: Ball (rolling element) 15: Outer peripheral surface (peripheral surface) 17: Groove 17b: Knurled groove 17c: Annular groove 20: Electric corrosion prevention member 21: Cover 22: Insulation Material 29: Adhesive layer 30: Part 38: Projection 41: Circumferential groove 42: Circumferential groove 46: First cover part 47: Second cover part C1: Central axis C2: Central axis K1: First region K2: First Two areas

Claims (11)

An inner ring, an outer ring, a plurality of rolling elements provided between the inner ring and the outer ring, and a circumferential surface that is attached to one of the inner ring and the outer ring and is cylindrical in the ring. Including an annular electric corrosion prevention member that covers at least
The electrolytic corrosion preventing member includes a rubber or resin insulating material that covers the peripheral surface and is fixed to the peripheral surface, and a cover that covers the insulating material and is fixed to the insulating material. , Anti-corrosion bearing.   The electrolytic corrosion-preventing bearing according to claim 1, wherein a groove into which a part of the insulating material enters is formed on the peripheral surface.   The electrolytic corrosion preventing bearing according to claim 2, wherein the groove is a knurled groove formed along a circumferential direction. The circumferential surface is formed with the knurled groove and a circumferential groove which is provided on both sides in the axial direction of the knurled groove and is recessed in the radial direction from the convex portion of the knurled groove,
The electrolytic corrosion-preventing bearing according to claim 3, wherein a part of the insulating material enters the knurled groove and the circumferential groove.   The electrolytic corrosion preventing bearing according to claim 2, wherein the groove is an annular groove formed along a circumferential direction, and a central axis of the annular groove is eccentric with respect to a central axis of the peripheral surface.   6. The electrolytic corrosion-preventing bearing according to claim 2, wherein a surface of the first region where the groove is formed is rougher than a second region other than the groove.   The cover has a cylindrical first cover portion located on the axially central side, a cylindrical second cover portion located on one side in the axial direction and closer to the circumferential surface than the first cover portion, The electrolytic corrosion-preventing bearing according to claim 1, comprising:   The said groove | channel is an electrolytic corrosion prevention bearing as described in any one of Claims 1-7 provided in the area | region of the center of the axial direction of the said bearing ring over the perimeter.   The electric corrosion prevention bearing according to any one of claims 1 to 8, wherein the insulating material is acrylic rubber.   The electric corrosion prevention bearing according to any one of claims 1 to 8, wherein the insulating material is nitrile rubber. The cover covers the insulating material via an adhesive layer,
11. The electrolytic corrosion-preventing bearing according to claim 1, wherein the insulating material directly covers the raceway ring.

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