Electrolytic corrosion-resistant bearing

Abstract

When attaching the anti-corrosion component to the raceway, the core metal prevents the covering component from getting caught between it and the raceway. [Solution] The corrosion-resistant bearing 10 includes an inner ring 11, an outer ring 12, a plurality of rolling elements, and an annular corrosion-resistant member 15 attached to one of the raceway rings, the inner ring 11 or the outer ring 12, and covering at least the cylindrical circumferential surface of the raceway ring. The corrosion-resistant member 15 includes a core metal 20 fitted into the raceway ring and an insulating covering member 30 that covers the first surface 21 of the core metal 20 on the mating member side. The core metal 20 has a second surface 22 opposite to the first surface 21, which has a press-fit surface 23 that is in close contact with the axial center of the circumferential surface of the raceway ring, and a non-press-fit surface 24 that is located axially first to the press-fit surface 23 and does not contact the circumferential surface of the raceway ring. At least the press-fit surface 23 is an exposed surface and is not covered by the covering member 30.

Description

Technical Field

[0001] The present invention relates to an anti-electric corrosion bearing.

Background Art

[0002] For example, in a rolling bearing used in an electric device such as a motor, a potential difference may occur between an inner ring and an outer ring. When a potential difference occurs, an electric current flows through the rolling elements inside the rolling bearing, and there is a risk of electric corrosion occurring on the raceways of the inner ring and the outer ring. When electric corrosion occurs on the raceway, abnormal noise may occur during rotation, peeling of the raceway may occur starting from the location where electric corrosion occurs, and the bearing life may be reduced.

[0003] In order to prevent electric corrosion, a bearing having an anti-electric corrosion member that covers the outer peripheral surface of the outer ring has been proposed (see, for example, Patent Document 1). The anti-electric corrosion member has a core metal attached to the outer ring and an insulating covering member that covers the core metal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] FIG. 7 is a cross-sectional view of a conventional anti-electric corrosion bearing. The anti-electric corrosion bearing 90 has an inner ring 91, an outer ring 92, a plurality of rolling elements 93, and an anti-electric corrosion member 94 attached to the outer ring 92 and covering the outer peripheral surface of the outer ring 92. The anti-electric corrosion member 94 has a core metal 95 fitted and attached to the outer ring 92 and an insulating covering member 96 that covers the core metal 95. In order to attach the anti-electric corrosion member 94 to the outer ring 92, they are brought closer to each other in the axial direction and fitted by press-fitting. Furthermore, in order to mount the completed corrosion-resistant bearing 90 onto the inner circumferential surface 991 of the housing 99, the corrosion-resistant bearing 90 is brought axially close to the housing 99 and press-fitted.

[0006] Figure 8 is a cross-sectional view showing a part of a conventional galvanic corrosion prevention member 94. In the manufacture of the galvanic corrosion prevention member 94, a rubber covering member 96 is molded using a core metal 95 as an insert in the mold. At that time, some of the rubber (rubber 97) that makes up the covering member 96 may flow out onto the inner circumferential surface of the core metal 95. Consequently, when attaching the corrosion prevention member 94 shown in Figure 8 to the outer ring 92, the flowing rubber 97 may tear and get caught between the core metal 95 and the outer ring 92, potentially increasing the pressing force. Furthermore, the aforementioned entanglement of rubber 97 may increase the outer diameter D (see Figure 7) of the corrosion prevention member 94. This increases the interference fit with the housing 99, resulting in increased resistance when pressing the corrosion prevention bearing 90 into the housing 99.

[0007] Therefore, the present invention aims to provide an electrocorrosion-resistant bearing that prevents the core metal from getting caught between the covering member and the raceway when the electrocorrosion-resistant member is mounted on the raceway. [Means for solving the problem]

[0008] The corrosion-resistant bearing of the present invention comprises an inner ring, an outer ring, a plurality of rolling elements, and an annular corrosion-resistant member attached to one of the raceways of the inner ring and the outer ring, covering at least the cylindrical circumferential surface of the raceway, wherein the corrosion-resistant member is in contact with a mating member, The electrolytic corrosion prevention member comprises a core metal that is fitted and attached to the raceway ring, and an insulating covering member that covers the first surface of the core metal that faces the mating member. The core metal has, on the second surface opposite to the first surface, a press-fit surface that is in close contact with the axial center of the circumferential surface of the raceway ring, and a non-press-fit surface that is located axially to the first side of the press-fit surface and does not contact the circumferential surface of the raceway ring. At least the press-fit surface is an exposed surface and is not covered by the covering member. [Effects of the Invention]

[0009] According to the corrosion-resistant bearing of the present invention, when the corrosion-resistant member is mounted on the raceway, it is possible to prevent the core metal from getting caught between the covering member and the raceway ring. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional view showing one embodiment of the corrosion-resistant bearing of the present invention. [Figure 2] Figure 2 is a cross-sectional view showing a part of the corrosion-resistant bearing shown in Figure 1. [Figure 3] Figure 3 is an explanatory diagram of the manufacturing method for the electrolytic corrosion prevention member. [Figure 4] Figure 4 is a cross-sectional view showing a part of the electrolytic corrosion prevention member. [Figure 5] Figure 5 is a cross-sectional view showing a portion of a corrosion-resistant bearing with different outer surface shapes of the covering material. [Figure 6] Figure 6 is a cross-sectional view showing a second embodiment of the corrosion-resistant bearing. [Figure 7] Figure 7 is a cross-sectional view of a conventional corrosion-resistant bearing. [Figure 8] Figure 8 is a cross-sectional view showing a part of a conventional electrolytic corrosion prevention member. [Modes for carrying out the invention]

[0011] <Summary of Embodiments of the Invention> The embodiments of the present invention are outlined below. (1) An embodiment of the present invention provides a corrosion-resistant bearing comprising an inner ring, an outer ring, a plurality of rolling elements, and an annular corrosion-resistant member attached to one of the raceways of the inner ring and the outer ring, which covers at least the cylindrical circumferential surface of the raceway, wherein the corrosion-resistant member is in contact with a mating member. The electrolytic corrosion prevention member comprises a core metal that is fitted and attached to the raceway ring, and an insulating covering member that covers the first surface of the core metal that faces the mating member. The core metal has, on a second surface opposite to the first surface, a press-fitting surface that adheres to the axially central portion of the circumferential surface of the raceway ring, and a non-press-fitting surface that is located on the first side in the axial direction from the press-fitting surface and is non-contact with the circumferential surface of the raceway ring. At least the press-fitting surface is an exposed surface not covered by the covering member.

[0012] The anti-electric corrosion member is mounted on the raceway ring by press-fitting between the raceway ring and the core metal. Even if the covering member covers a part of the non-press-fitting surface, since the press-fitting surface is not covered by the covering member, when mounting, the core metal is prevented from winding the covering member between it and the raceway ring.

[0013] (2) In the anti-electric corrosion bearing of (1) above, the raceway ring has a raceway surface on which the rolling elements rollingly contact, and the core metal has, on the second surface, a stepped surface that is located on the first side in the axial direction of the press-fitting surface and connects the press-fitting surface and the non-press-fitting surface, and the boundary between the stepped surface and the press-fitting surface is located on the first side in the axial direction from the portion of the raceway surface where the rolling elements can contact. When a radial load acts on the inner ring, the rolling elements, and the outer ring, the load is transmitted to the mating member through the press-fitting portion of the core metal having the press-fitting surface and the portion of the covering member that covers the press-fitting portion. Although the core metal has a non-press-fitting surface that is non-contact with the raceway ring, according to the above configuration, since the radial load is transmitted to the mating member through the press-fitting portion, a decrease in bearing rigidity in the radial direction is suppressed.

[0014] (3) In the anti-electric corrosion bearing of (1) or (2) above, the covering member has a plurality of protruding portions that protrude toward the mating member side and are in close contact with the mating member. The spaces between the plurality of protruding portions form recesses. When a lubricant such as oil is applied to the circumferential surface of the anti-electric corrosion bearing for mounting it on the mating member, the lubricant is stored in the recesses, and the lubricant in the recesses is utilized, making it easier to mount the anti-electric corrosion bearing.

[0015] (4) In any one of the anti-electric corrosion bearings according to (1) to (3) above, the thickness of the press-fitting portion having the press-fitting surface among the mandrels is not less than the thickness of the portion of the covering member that covers the press-fitting portion. Among the covering members, the thickness of the portion that covers the press-fitting portion of the mandrel is small, and it is possible to reduce the amount of elastic deformation when a radial load acts.

[0016] (5) In any one of the anti-electric corrosion bearings according to (1) to (4) above, the covering member has an end portion that covers the portion having the non-press-fitting surface from the first side in the axial direction, and the circumferential surface on the raceway ring side among the end portions and the non-press-fitting surface are located along the same virtual cylindrical surface. When manufacturing the anti-electric corrosion member, the mandrel is used as an insert part of the mold, and the covering member is molded. According to the above configuration, the mold shape is simplified.

[0017] (6) In the anti-electric corrosion bearing according to (2) above, the rolling element is a ball, the raceway surface is a circumferential groove having a concave arc shape in cross section, and when an axial component load acts on the inner ring, the ball, and the outer ring, the ball contacts the circumferential groove at a position on the second side in the axial direction from the bottom point of the circumferential groove. Even when an axial component load acts on the anti-electric corrosion bearing in addition to the radial component load, according to the above configuration, the radial component load is transmitted to the mating member through the press-fitting portion.

[0018] <Details of Embodiments of the Present Invention> [Overall Configuration of Anti-Electric Corrosion Bearing] FIG. 1 is a cross-sectional view showing an embodiment of the anti-electric corrosion bearing of the present invention. The anti-electric corrosion bearing 10 shown in FIG. 1 is a rolling bearing, and includes an inner ring 11, an outer ring 12, a plurality of rolling elements, and an annular cage 14 that holds the plurality of rolling elements. The rolling elements in the present embodiment are balls 13. The anti-electric corrosion bearing 10 has an annular anti-electric corrosion member 15. The anti-electric corrosion member 15 is attached to the outer ring 12, which is a raceway ring. In the state where the anti-electric corrosion member 15 is attached to the outer ring 12, it covers the outer peripheral surface 16, which is cylindrical, of the outer ring 12 and also covers the side surface 17 of the outer ring 12.

[0019] The corrosion-resistant bearing 10 is attached to the housing 7 by press-fitting the outer ring 12, to which the corrosion-resistant member 15 is attached, into the inner circumferential surface 71 of the housing 7. The corrosion-resistant member 15 is in contact with the housing 7. The housing 7 is the mating member to which the corrosion-resistant bearing 10 is attached. The corrosion-resistant bearing 10 rotatably supports the shaft 8 relative to the housing 7.

[0020] Multiple balls 13 are arranged between a cylindrical inner ring 11 and a cylindrical outer ring 12, and the central axis of the inner ring 11 and the central axis of the outer ring 12 coincide. This central axis becomes the central axis C of the corrosion-resistant bearing 10. The direction along the central axis C and the direction parallel to the central axis C are defined as the axial direction of the corrosion-resistant bearing 10. The direction perpendicular to the central axis C is defined as the radial direction of the corrosion-resistant bearing 10. The direction along the circle centered on the central axis C is defined as the circumferential direction of the corrosion-resistant bearing 10. In each figure, including Figure 1, the right side is the "first axial side," and the left side is the "second axial side."

[0021] The inner ring 11 has a raceway surface on which the ball 13 rolls and makes contact. The raceway surface of the inner ring 11 is a circumferential groove 41 with a concave arc cross-section. The outer ring 12 has a raceway surface on which the ball 13 rolls and makes contact. The raceway surface of the outer ring 12 is a circumferential groove 42 with a concave arc cross-section. The outer circumferential surface 16 of the outer ring 12 has a first outer circumferential surface 161 with a larger outer diameter, a second outer circumferential surface 162 with a smaller outer diameter than the first outer circumferential surface 161, and a third outer circumferential surface 163 located between the first outer circumferential surface 161 and the second outer circumferential surface 162. The third outer circumferential surface 163 is an inclined surface that widens in diameter toward the first axial direction.

[0022] [Electrolytic corrosion prevention member 15] The electrolytic corrosion prevention member 15 has a core metal 20 and a covering member 30. Figure 2 is a cross-sectional view showing a part of the electrolytic corrosion prevention bearing 10. The mandrel 20 is fitted and attached to the outer ring 12. The mandrel 20 has a cylindrical portion 201 located radially outward from the outer ring 12 and an annular portion 202 located on the second axial side of the outer ring 12. The cylindrical portion 201 has a first surface 21 facing the housing 7 and a second surface 22 opposite to the first surface 21 and facing the outer ring 12. The annular portion 202 has a third surface 28 facing the housing 7 and a fourth surface 29 facing the outer ring 12.

[0023] The covering member 30 covers the first surface 21 and the third surface 28 of the core metal 20. The covering member 30 is made of rubber and is elastic and electrically insulating. The covering member 30 is formed by vulcanization molding. Figure 3 is an explanatory diagram of the manufacturing method of the electrolytic corrosion prevention member 15. When manufacturing the electrolytic corrosion prevention member 15, the core metal 20 is used as an insert in the mold 70 to form the covering member 30. The mold 70 has, for example, a first mold 71 and a second mold 72, and the core metal 20 is fixed in the first mold 71. The covering member 30 is formed in the cavity 73 formed between the first mold 71 and the second mold 72. The core metal 20 is vulcanized and bonded to the covering member 30.

[0024] Figure 4 is a cross-sectional view showing a part of the galvanic corrosion prevention member 15. The core metal 20 has a press-fit surface 23 and a first non-press-fit surface 24 located axially first to the press-fit surface 23 on the second surface 22 which is the inner circumference side. In this embodiment, the core metal 20 has a second non-press-fit surface 52 on the second surface 22 which is located axially second to the press-fit surface 23.

[0025] The press-fit surface 23, the first non-press-fit surface 24, and the second non-press-fit surface 52 have shapes that follow cylindrical surfaces with different diameters centered on the central axis C (see Figure 1). The inner diameter D24 of the first non-press-fit surface 24 is larger than the inner diameter D23 of the press-fit surface 23 (D24 > D23). The inner diameter D52 of the second non-press-fit surface 52 is smaller than the inner diameter D23 of the press-fit surface 23 (D52 <D23)。

[0026] The core metal 20 has, on the second surface 22, a first step surface 25 located on the first axial side of the press-fitting surface 23. The first step surface 25 is a surface connecting the press-fitting surface 23 and the first non-press-fitting surface 24. The first step surface 25 is a short portion in the axial direction and is an inclined surface that expands in diameter toward the first axial side. The core metal 20 has, on the second surface 22, a second step surface 55 located on the second axial side of the press-fitting surface 23. The second step surface 55 is a surface connecting the press-fitting surface 23 and the second non-press-fitting surface 52. The second step surface 55 is a short portion in the axial direction and is an inclined surface that expands in diameter toward the first axial side.

[0027] The cylindrical portion 201 of the core metal 20 includes a press-fitting portion 26 having the press-fitting surface 23 on its inner circumference, a first non-press-fitting portion 27 having the first non-press-fitting surface 24 on its inner circumference, and a second non-press-fitting portion 53 having the second non-press-fitting surface 52 on its inner circumference. In the case of this embodiment, the thicknesses (dimensions in the radial direction) of the press-fitting portion 26, the first non-press-fitting portion 27, and the second non-press-fitting portion 53 are all the same "t1".

[0028] As shown in FIGS. 2 and 4, the inner diameter D23 of the press-fitting surface 23 is smaller than the outer diameter D161 of the first outer peripheral surface 161 of the outer ring 12 (D23 < D161). Therefore, by press-fitting the outer ring 12 onto the core metal 20, the electric corrosion prevention member 15 is attached to the outer ring 12. The press-fitting surface 23 adheres to the axial center portion of the outer peripheral surface 16 of the outer ring 12.

[0029] The inner diameter D24 of the first non-press-fitting surface 24 is larger than the outer diameter D161 of the first outer peripheral surface 161 of the outer ring 12 (D24 > D161). The first non-press-fitting surface 24 is non-contact with the outer peripheral surface 16 (first outer peripheral surface 161) of the outer ring 12. A gap e is provided between the first non-press-fitting surface 24 and the outer peripheral surface 16 (first outer peripheral surface 161) of the outer ring 12. The inner diameter D52 of the second non-press-fitting surface 52 is larger than the outer diameter D162 of the second outer peripheral surface 162 of the outer ring 12 (D52 > D162). The second non-press-fitting surface 52 is non-contact with the outer peripheral surface 16 (second outer peripheral surface 162) of the outer ring 12.

[0030] As shown in Figure 4, the covering member 30 has a first covering portion 36 which covers the press-fit portion 26 of the core metal 20, a second covering portion 37 which covers the first non-press-fit portion 27, and a third covering portion 54 which covers the second non-press-fit portion 53. The covering member 30 has an end portion 34 that covers the first non-press-fit portion 27 from the first axial side. The inner circumferential surface 341 of the end portion 34 on the outer ring 12 side and the first non-press-fit surface 24 of the core metal 20 are located along the same virtual cylindrical surface K1 centered on the central axis C (see Figure 1). In other words, the inner circumferential surface 341 of the end portion 34 and the first non-press-fit surface 24 are flush. Therefore, the mold 70 (first mold 71) in the boundary region between the inner circumferential surface 341 of the end portion 34 of the covering member 30 and the first non-press-fit surface 24 of the core metal 20 is also flush, and the shape of the mold 70 is simplified.

[0031] As shown in Figure 3, when the covering member 30 is molded by the mold 70, some of the rubber constituting the covering member 30 may flow out to the inner circumference of the core metal 20 through the gap between the first non-press-fit portion 27 of the core metal 20 and the first mold 71. Figure 2 shows the portion that has flowed out between the core metal 20 and the first mold 71 as "rubber 35". In other words, the first non-press-fit surface 24 may be partially covered by the rubber 35, which is part of the covering member 30, at its first axial end.

[0032] The first non-press-fit portion 27 of the core metal 20 has an axial dimension L1 that is larger than its thickness t1 (radial dimension). In the illustrated example, the axial dimension L1 of the first non-press-fit portion 27 is more than three times the thickness t1 of the core metal 20. In other words, the first non-press-fit portion 27 is long in the axial direction. As shown in Figure 3, the first non-press-fit surface 24 is in contact with the first mold 71. Therefore, the rubber 35 that flows out is only a part of the first axial side of the first non-press-fit surface 24 and cannot reach the press-fit surface 23.

[0033] Thus, although some of the rubber constituting the covering member 30 (rubber 35) may leak out on the inner circumference side of the non-press-fit surface 24, almost the entire non-press-fit surface 24 is exposed and not covered by the rubber of the covering member 30. The press-fit surface 23 is located axially second to the non-press-fit surface 24 and is in contact with the second mold 72. For this reason, the entire press-fit surface 23 is exposed and not covered by the covering member 30.

[0034] As described above, even if the first non-press-fit surface 24 is covered by the covering member 30 (rubber 35) in a portion of the first axial side, the press-fit surface 23 is not covered by the covering member 30. In other words, in the cylindrical portion 201 of the core metal 20, at least the press-fit surface 23 is not covered by the covering member 30 and is an exposed surface. Furthermore, the second non-press-fit surface 52, which is located on the second axial side of the press-fit surface 23, is also not covered by the covering member 30 and is an exposed surface.

[0035] As described above (see Figure 2), the anti-corrosion member 15 is attached to the outer ring 12 by press-fitting the outer ring 12 onto the core metal 20. In other words, the anti-corrosion member 15 is attached to the outer ring 12 by bringing the axial first side portion (end 34) of the anti-corrosion member 15 closer to the outer ring 12 in the axial direction and fitting the core metal 20 onto the outer ring 12.

[0036] As described above, a gap e is provided between the first non-press-fit surface 24 of the core metal 20 and the first outer peripheral surface 161 of the outer ring 12. Furthermore, the press-fit surface 23 of the core metal 20 is not covered by the covering member 30. Therefore, even if the covering member 30 (the rubber that has flowed out 35) covers a part of the first non-press-fit surface 24, when the electrolytic corrosion prevention member 15 is attached to the outer ring 12, the core metal 20 does not wrap the covering member 30 (rubber 35) between itself and the outer ring 12.

[0037] In this embodiment (see Figure 2), in the core metal 20, the boundary Q1 between the stepped surface 25 and the press-fit surface 23 is located axially first (to the right in the case of Figure 2) of the portion 421 of the circumferential groove (raceway surface) 42 of the outer ring 12 that the ball 13 can contact. When a radial load is applied to the bearing portion 18, which includes the inner ring 11, the balls 13, and the outer ring 12, the load is transmitted to the housing 7 via the press-fit portion 26 of the mandrel 20 and the first covering portion 36 of the covering member 30 that covers the press-fit portion 26. The radial load acting on the bearing portion 18 is transmitted to the housing 7 through the press-fit portion 26, which is in contact with the outer ring 12, rather than through the non-press-fit portion 27, which is not in contact with the outer ring 12. With this configuration, the mandrel 20 has a first non-press-fit surface 24 that is not in contact with the outer ring 12, but the reduction in bearing rigidity in the radial direction is suppressed.

[0038] In particular, in this embodiment, the inner ring 11, which rotates integrally with the shaft 8 (see Figure 1), may be subjected to an axial load acting on the outer ring 12 attached to the housing 7, with the axial component moving from the first axial side to the second axial side. When an axial load as described above is applied to the bearing portion 18, including the inner ring 11 and the outer ring 12, the ball 13 contacts the circumferential groove 42 at a position P1 that is second axially to the bottom point 422 of the circumferential groove 42 (to the left in the case of Figure 1). The bottom point 422 is the point of the circumferential groove 42 that is radially outermost. Thus, even when an axial load acts on the corrosion-resistant bearing 10 in addition to a radial load, according to the configuration of this embodiment, the radial load is transmitted to the housing 7 through the press-fit portion 26.

[0039] As described above, the covering member 30 has a first covering portion 36 that covers the press-fit portion 26 of the core metal 20 and a second covering portion 37 that covers the first non-press-fit portion 27 of the core metal 20. The thickness t1 of the press-fit portion 26 (see Figure 4) is greater than or equal to the thickness t2 of the first covering portion 36 of the covering member 30 (t1≧t2). In other words, the thickness t2 of the first covering portion 36 of the covering member 30 is smaller than that of the press-fit portion 26 of the core metal 20. Therefore, when a radial load is applied to the bearing portion 18, it is possible to reduce the amount of elastic deformation in the covering member 30. As a result, although the corrosion-resistant bearing 10 has a covering member 30 that can be elastically deformed, it is possible to suppress the amount of radial displacement of the shaft 8 supported by the corrosion-resistant bearing 10.

[0040] The thickness t3 of the second covering portion 37 is smaller than the thickness t2 of the first covering portion 36 (t3 < t2). The thickness t3 of the second covering portion 37 is smaller than the thickness t1 of the core metal 20 (t3 < t1). The second covering portion 37 has a small thickness (minimum thickness) sufficient to surely form a rubber film on the core metal 20.

[0041] In the case of the form shown in FIG. 2, the outer peripheral surface 301 of the covering member 30 has a cross-sectional straight shape along a single cylindrical surface centered on the central axis C (see FIG. 1) from the end portion 34 located on the first side in the axial direction to the third covering portion 54 through the second covering portion 37 and the first covering portion 36.

[0042] FIG. 5 is a cross-sectional view showing a part of the anti-electric corrosion bearing 10 in which the shape of the outer peripheral surface 301 of the covering member 30 is different. The modified example shown in FIG. 5 has a different shape of the outer peripheral surface 301 of the covering member 30 compared to the form shown in FIG. 2, but is otherwise the same. The same components are denoted by the same reference numerals, and the description of the same components is omitted. [[ID=A]]

[0043] [[ID=B]] In the case of the modified example shown in FIG. 5, the covering member 30 has a plurality of protruding portions 31 that protrude toward the housing 7 side and are in close contact with the housing 7. In the example shown in FIG. 4, the covering member 30 has two protruding portions 31 on its outer peripheral side. A concave portion 33 is formed between the two protruding portions 31. The concave portion 33 is located between the first step surface 25 and the second step surface 55 of the core metal 20 with respect to the axial position. The protruding portions 31 are in close contact with the inner peripheral surface 71 of the housing 7. The concave portion 33 may be in contact with or non-contact with the inner peripheral surface 7

[0044] 1 of the housing 7.

[0044] In order to press-fit the anti-electric corrosion bearing 10 into the housing 7, a lubricant such as oil is applied to the outer peripheral surface 301 of the covering member 30. In this case, the lubricant is stored in the concave portion 33. The lubricant in the concave portion 33 is utilized, and the installation of the anti-electric corrosion bearing 10 becomes easy.

[0045] 〔Second form of the anti-electric corrosion bearing 10〕 In the first embodiment shown in Figure 1, the anti-corrosion member 15 is attached to the outer ring 12. Figure 6 is a cross-sectional view showing the second embodiment of the anti-corrosion bearing 10. In the second embodiment, the anti-corrosion member 15 is attached to the inner ring 11.

[0046] The corrosion-resistant bearing 10 shown in Figure 6 is a rolling bearing and has an inner ring 11, an outer ring 12, a plurality of rolling elements, and an annular cage 14 that holds the plurality of rolling elements. The rolling elements are balls 13. The above points are the same as in the first embodiment. The corrosion-resistant bearing 10 has an annular corrosion-resistant member 15, which is attached to the inner ring 11, which is a raceway ring, and covers the cylindrical inner circumferential surface 19 of the inner ring 11.

[0047] The corrosion-resistant bearing 10 is attached to the shaft 8 by press-fitting the shaft 8 into the inner circumference of the corrosion-resistant member 15 mounted on the inner ring 11. The corrosion-resistant member 15 is in contact with the shaft 8. The shaft 8 is the mating member to which the corrosion-resistant bearing 10 is attached. The corrosion-resistant bearing 10 rotatably supports the shaft 8 with respect to the housing 7.

[0048] The corrosion prevention member 15 shown in Figure 6 has a similar configuration to the corrosion prevention member 15 shown in Figure 1, although it is reversed in the radial direction. Each component is reversed on the inner and outer circumference sides, but similar components are given the same reference numerals in both the first and second embodiments.

[0049] The second form of the electrolytic corrosion prevention member 15 has a core metal 20 that is fitted and attached to the inner ring 11, and a covering member 30 that covers the first surface 21 of the core metal 20 on the shaft 8 side. The covering member 30 is made of rubber and is elastic and electrically insulating. Similar to the first form, the second form of the galvanic corrosion prevention member 15 is manufactured by molding a covering member 30 using a core metal 20 as an insert in a mold.

[0050] The core metal 20 has a second surface 22 opposite to the first surface 21, which has a press-fit surface 23 that is in close contact with the axial center of the inner circumferential surface 111 of the inner ring 11, and a first non-press-fit surface 24 that is located axially to the first side of the press-fit surface 23 and does not contact the inner circumferential surface 111 of the inner ring 11. As explained in Figure 3 regarding the first embodiment, when the covering member is molded using a mold, some of the rubber constituting the covering member may flow out to the outer circumference of the core metal 20 through the gap between the first non-press-fit surface 24 (first non-press-fit portion 27) of the core metal 20 and the first mold. However, similar to the first embodiment, almost the entire first non-press-fit surface 24 is not covered by the covering member 30 and is an exposed surface. Furthermore, the press-fit surface 23 is not covered by the covering member 30 and is an exposed surface throughout its entirety. In other words, at least the press-fit surface 23 is not covered by the covering member 30 and is an exposed surface.

[0051] The anti-corrosion member 15 is attached to the inner ring 11 by press-fitting the inner ring 11 with the core metal 20. Even if a portion of the first non-press-fit surface 24 is covered by the rubber of the covering material 30 that flows out during molding with a mold, the press-fit surface 23 is not covered by the covering material 30. Therefore, when attaching the anti-corrosion member 15 to the inner ring 11, the core metal 20 does not get the covering material 30 (the flowed-out rubber) caught between itself and the inner ring 11.

[0052] The inner ring 11 has a raceway surface on which the ball 13 rolls and makes contact. The raceway surface of the inner ring 11 is a circumferential groove 41 with a concave circular arc cross-section. The core metal 20 has a first stepped surface 25 on the second surface 22 on the inner ring 11 side, which is located on the first axial side of the press-fit surface 23 and connects the press-fit surface 23 and the first non-press-fit surface 24. The boundary Q1 between the first stepped surface 25 and the press-fit surface 23 is located on the first axial side of the portion 411 of the circumferential groove 41 that the ball 13 can contact.

[0053] Therefore, when a radial load is applied to the bearing portion 18, which includes the inner ring 11, the balls 13, and the outer ring 12, the load is transmitted to the shaft 8 via the press-fit portion 26 of the core metal 20, which has a press-fit surface 23, and the first covering portion 36 of the covering member 30, which covers the press-fit portion 26. In other words, the corrosion-resistant bearing 10 can support the radial component load from the shaft 8 through the press-fit portion 26. Thus, the radial load is transmitted from the shaft 8 to the bearing portion 18 through the press-fit portion 26. For this reason, although the core metal 20 has a non-press-fit surface 24 that does not contact the inner ring 11, the reduction in bearing rigidity in the radial direction is suppressed.

[0054] In particular, in the configuration shown in Figure 6, when an axial load is applied to the bearing portion 18, the ball 13 contacts the circumferential groove 41 at a position P1 that is second axially to the bottom point 412 of the circumferential groove 41. Even when an axial load acts on the corrosion-resistant bearing 10 in addition to a radial load, according to the above configuration, the radial load from the shaft 8 is transmitted to the bearing portion 18 through the press-fit portion 26.

[0055] The covering member 30 has an end portion 34 that covers the first non-press-fit portion 27, which is the part of the core metal 20 that has a non-press-fit surface 24, from the first axial side. The outer circumferential surface of the end portion 34 on the inner ring 11 side and the first non-press-fit surface 24 are located along the same virtual cylindrical surface K2. In other words, the outer circumferential surface 342 of the end portion 34 and the first non-press-fit surface 24 are flush.

[0056] The thickness t1 of the press-fit portion 26 having the press-fit surface 23 of the core metal 20 is greater than or equal to the thickness t2 of the first covering portion 36 of the covering member 30 that covers the press-fit portion 26 (t1≧t2). In other words, the thickness t2 of the first covering portion 36 is small. Therefore, it is possible to reduce the amount of elastic deformation of the covering member 30 when a radial load is applied to the bearing portion 18. This makes it possible to suppress the amount of radial displacement of the shaft 8 supported by the corrosion-resistant bearing 10.

[0057] In the configuration shown in Figure 6, the inner circumferential surface 302 of the covering member 30 has a shape that follows a single cylindrical surface centered on the central axis C, from the end portion 34 located on the first axial side, through the second covering portion 37 and the first covering portion 36, to the third covering portion 54. Similar to the first embodiment, which illustrates the shape of the outer periphery of the covering member 30 with reference to Figure 5, the covering member 30 of the second embodiment shown in Figure 6 may also have multiple (two) protrusions, although these are not shown. The protrusions extend toward the shaft 8 and are in close contact with the shaft 8.

[0058] In this case, the space between the multiple (two) protrusions becomes a recess. When a lubricant such as oil is applied to the inner circumferential surface 302 of the covering member 30 in order to mount the anti-corrosion bearing 10 onto the shaft 8, the lubricant accumulates in the recess, and the lubricant in the recess is utilized, making it easier to mount the anti-corrosion bearing 10.

[0059] In both the first and second embodiments described above, when attaching the anti-corrosion member 15 to the raceway ring (outer ring 12 or inner ring 11), the axial first side portion (end 34) of the anti-corrosion member 15 is the starting point for attachment to the raceway ring (outer ring 12 or inner ring 11). In other words, the axial first side portion (end 34) of the anti-corrosion member 15 is brought axially close to the raceway ring (outer ring 12 or inner ring 11) and the core metal 20 is fitted into the raceway ring (outer ring 12 or inner ring 11). This attaches the anti-corrosion member 15 to the raceway ring (outer ring 12 or inner ring 11).

[0060] In the first and second embodiments described above, the rolling element is a ball 13, but the rolling element of the corrosion-preventing bearing 10 of the present invention may be something other than a ball 13, and may be a roller.

[0061] 〔others〕 The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the embodiments described above and includes all modifications within the scope equivalent to the configurations described in the claims. [Explanation of Symbols]

[0062] 7 Housing (Mating component) 8 axes (for mating member) 10. Corrosion-resistant bearings 11 Inner circle 12 Outer ring 13 Balls (rolling bodies) 15. Electrolytic corrosion prevention material 16. Outer surface (circumferential surface of a cylindrical shape) 19. Inner circumferential surface (circumferential surface of a cylindrical shape) 20 Mandrel 21 Front page 22 Second side 23 Press-fit surface 24. First non-press-fit surface (non-press-fit surface) 25 First step surface (step surface) 26 Press-fit section 30 Covering member 31 Protrusion 34 End 36 First covering portion (part that covers the press-fit portion) 41 Circumferential groove (raceway surface) 42 Circumferential groove (raceway surface) 341 Inner peripheral surface (peripheral surface) 411 The part that the ball (rolling element) can make contact with 412 Bottom point 421 The part that the ball (rolling element) can make contact with 422 Bottom point K1 Virtual cylindrical surface K2 virtual cylindrical surface Q1 boundary

Claims

1. A corrosion-resistant bearing comprising an inner ring, an outer ring, a plurality of rolling elements, and an annular corrosion-resistant member attached to one of the raceways of the inner ring and the outer ring, which covers at least the cylindrical circumferential surface of the raceway, wherein the corrosion-resistant member is in contact with a mating member, The aforementioned electrolytic corrosion prevention member is A core metal that is fitted and attached to the aforementioned raceway, It comprises an insulating covering member that covers the first surface of the core metal that is on the mating member side, The aforementioned core metal is The second surface, which is opposite to the first surface, has a press-fit surface that is in close contact with the axial center of the circumferential surface of the raceway ring, and a non-press-fit surface that is located axially to the first side of the press-fit surface and does not contact the circumferential surface of the raceway ring. At least the press-fit surface is an exposed surface not covered by the covering member. Electrolytic corrosion-resistant bearing.

2. The aforementioned raceway wheel has a raceway surface on which the rolling body rolls and makes contact. The core metal has a stepped surface on the second surface that is located on the first axial side of the press-fit surface and connects the press-fit surface and the non-press-fit surface. The boundary between the stepped surface and the press-fit surface is located on the first axial side of the portion of the raceway surface that the rolling element can contact. The corrosion-resistant bearing according to claim 1.

3. The anti-corrosion bearing according to claim 1 or claim 2, wherein the covering member has a plurality of protrusions that protrude toward the mating member and are in close contact with the mating member.

4. The corrosion-resistant bearing according to claim 1 or claim 2, wherein the thickness of the press-fit portion of the core metal having the press-fit surface is equal to or greater than the thickness of the portion of the covering member that covers the press-fit portion.

5. The covering member has an end portion that covers the portion having the non-press-fit surface from the first axial side, The corrosion-resistant bearing according to claim 1 or claim 2, wherein the circumferential surface of the end portion on the raceway side and the non-press-fit surface are located along the same virtual cylindrical surface.

6. The rolling element is a ball, and the raceway surface is a circumferential groove with a concave circular arc cross-section. The corrosion-resistant bearing according to claim 2, wherein when an axial load is applied to the inner ring, the balls, and the outer ring, the balls contact the circumferential groove at a position second axially from the bottom of the circumferential groove.

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