Electric corrosion prevention bearing structure

Abstract

To provide an electric corrosion prevention bearing structure having high productivity and capable of maintaining an excellent electric corrosion suppression effect over a long period of time, compared to a case where an insulating film is formed on an outer ring or inner ring.SOLUTION: An electric corrosion prevention bearing structure (bearing structure 100) of the present invention comprises a housing 110, a bearing 120 attached to the housing 110, and a cylindrical insulation ring 130 arranged between the housing 110 and the bearing 120. The insulation ring 130 is made of aluminum or an aluminum alloy, and has an alumite coating formed on its surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an anti-galvanic corrosion bearing structure comprising a housing and a bearing mounted therein. [Background technology]

[0002] In recent years, with the progress of development of electric vehicles (EVs) and hybrid electric vehicles (HVs), the number of high-voltage parts installed in each automobile is increasing. When current from these high-voltage parts is passed through a bearing, electrolytic corrosion occurs on the surfaces of the rolling elements of the bearing and on the raceway surfaces of the outer and inner rings, which is one of the causes of damage. To address this issue, resin coatings are formed on the surfaces of the outer and inner rings by insert molding, or ceramic coatings are sintered, as in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-72101 Summary of the Invention [Problem to be solved by the invention]

[0004] When forming a ceramic coating on the surface of the outer ring as in Patent Document 1, a paste-like material must be sprayed onto the outer peripheral surface of the outer ring etc. and then fired, making the processing process complicated. This makes it difficult to control the film thickness and improve productivity. In addition, although ceramic coatings are hard, they tend to peel off, and because the insulating coating is hard and difficult to grind and finish after it is formed, there is the issue of variations in the mating surfaces.

[0005] In view of these problems, the present invention aims to provide an electrolytic corrosion-preventing bearing structure that is more productive and can maintain good electrolytic corrosion inhibition effects over a long period of time compared to a case in which an insulating coating is formed on the outer ring or the inner ring. [Means for solving the problem]

[0006] In order to solve the above problems, a typical configuration of an electrolytic corrosion-resistant bearing structure according to the present invention comprises a housing, a bearing attached to the housing, and a cylindrical insulating ring arranged between the housing and the bearing, the insulating ring being made of aluminum or an aluminum alloy and having an anodized coating formed on its surface.

[0007] The housing may have a fitting hole into which the insulating ring is fitted and a chamfer formed on the edge of the fitting hole, the radial width of the chamfer being non-uniform in the circumferential direction, and a crimped portion bent toward the chamfer by crimping at the end of the insulating ring. This makes it possible to integrate the insulating ring with the housing and prevent the insulating ring from rotating relative to the housing. As another method for integrating the insulating ring with the housing, an adhesive or the like may be interposed between the housing and the insulating ring. Effect of the Invention

[0008] According to the present invention, it is possible to provide an electrolytic corrosion prevention bearing structure which is more productive and capable of maintaining a good electrolytic corrosion inhibition effect for a long period of time compared to a case in which an insulating coating is formed on the outer ring or the inner ring. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an electrolytic corrosion prevention bearing structure according to an embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view and a front view of the housing of FIG. 1. [Diagram 3] 5A to 5C are diagrams illustrating another example of the bearing structure of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, shapes, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown or explained.

[0011] 1 is a diagram illustrating an electrolytic corrosion prevention bearing structure according to this embodiment (hereinafter referred to as a bearing structure 100). As shown in FIG.

[0012] A disc spring 140 is disposed between the bearing 120 and annular portion 134 (described later) of the insulating ring 130. The disc spring 140 biases an outer ring 122 of the bearing 120 in the axial direction, so that a preload is applied. An O-ring 150 is fitted on the bearing 120 (strictly speaking, the outer ring 122 described later). This prevents rotation between the outer ring 122 and the insulating ring 130, suppresses creep between the bearing 120 and the insulating ring 130, and also provides an anti-vibration effect against axial vibration.

[0013] Bearing 120 is a device attached to housing 110 and rotatably supports shaft 102. Bearing 120 includes an outer ring 122, an inner ring 124, and rolling elements 126. Rolling elements 126 are disposed between outer ring 122 and inner ring 124 and roll between them. Note that, although balls are exemplified as rolling elements 126 in this embodiment, the present invention is not limited thereto, and it is also possible to apply the present invention to the use of rollers (not shown) as rolling elements 126.

[0014] The insulating ring 130 is a cylindrical member disposed between the housing 110 and the bearing 120 (the outer ring 122 of the bearing 120 in this embodiment). The insulating ring 130 has a cylindrical portion 132, an annular portion 134, and a crimped portion 136 described below. The cylindrical portion 132 is a portion disposed between the housing 110 and the bearing 120. The annular portion 134 is a portion that bends from one end 132a of the cylindrical portion 132 and extends axially inward.

[0015] The insulating ring 130 of this embodiment is made of aluminum or an aluminum alloy, and has an anodized aluminum coating formed on its surface. That is, in the insulating ring 130, the surface of a base material made of aluminum or an aluminum alloy is anodized to form an anodized aluminum coating on the surface of the base material. The anodized aluminum coating may be formed on at least one of the outer peripheral surface 130a and the inner peripheral surface 130b of the insulating ring 130, or may be formed on both surfaces. More preferably, the insulating performance can be further improved by forming an anodized aluminum coating on the ends 130c and 130d of the insulating ring as well.

[0016] The aluminum and aluminum alloys used as the base material have the advantage of being soft and easy to press mold. Anodized coatings have high insulation properties and high hardness. For example, hard anodizing can achieve a thickness of about 0.05 mm and a hardness of about HV400 (about half that of bearing steel). This allows the formation of a coating with high wear resistance. When the anodized coating is set to about 0.05 mm thick, it is also possible to perform grinding finishing while leaving the required thickness.

[0017] By using the metal insulating ring 130 with the anodized aluminum coating formed thereon as in the above configuration, it is possible to obtain higher rigidity than a resin insulating coating, and it is possible to prevent peeling compared to a ceramic coating. In addition, the process of forming the anodized aluminum coating by anodizing is easier than the firing process. Therefore, the processing process can be simplified, and the film thickness can be easily controlled. Therefore, according to the bearing structure 100 of this embodiment, it is possible to achieve higher productivity and maintain a good electrolytic corrosion suppression effect for a long period of time, compared to the case where a resin insulating coating is formed on the outer ring or the inner ring.

[0018] In particular, when an anodized aluminum coating is formed on both the outer peripheral surface 130a and the inner peripheral surface 130b of the insulating ring 130, it can be considered that two layers of anodized aluminum coating are formed on the insulating ring 130. Therefore, even if the anodized aluminum coating on either the outer peripheral surface 130a or the inner peripheral surface 130b wears away, it is possible for the insulating performance to be sufficiently maintained by the other anodized aluminum coating.

[0019] For example, assume that the bearing outer ring 122 slides axially on the inner peripheral surface 130b of the insulating ring 130 due to the disc spring 140, and as a result, the anodized aluminum coating on the inner peripheral surface 130b is worn away. Even in such a case, if the insulating ring 130 is fixed to the housing 110, at least the anodized aluminum coating on the outer peripheral surface 130a will not be worn away, and the insulating performance will be maintained.

[0020] Furthermore, since the housing 110 is often made of aluminum or an aluminum alloy, like the insulating ring 130, the difference in linear expansion coefficient between them is extremely small. This makes it possible to effectively prevent the occurrence of a gap between the housing 110 and the insulating ring 130 and the occurrence of relative misalignment.

[0021] Figure 2 is a cross-sectional view and a front view of the housing 110 of Figure 1. Figure 2(a) is a cross-sectional view of the housing 110 of Figure 1, and Figure 2(b) is a front view of the housing 110 of Figure 1. As shown in Figure 2, the housing 110 has a fitting hole 112 into which an insulating ring 130 is fitted, and a chamfer 114 is formed on the edge 112a of the fitting hole 112.

[0022] The radial width of the chamfer 114 is non-uniform in the circumferential direction. Specifically, in this embodiment, the center of rotation of the tool for chamfering the edge of the fitting hole 112 is eccentrically processed with respect to the center of the fitting hole 112. Then, since the cutting amount changes in the circumferential direction, the width of the chamfer 114 (the radial width between the outer circumferential circle 114a and the inner circumferential circle 114b) changes from width W1 to width W2 (W1 < W2), becoming non-uniform in the circumferential direction.

[0023] In addition, as a configuration for making the radial width of the chamfer 114 non-uniform in the circumferential direction, not only eccentric chamfering is performed, but also recesses and notches are formed in a part of the chamfer 114 by cutting or pressing, and corresponding shapes are also provided on the insulating ring, and they are fixed at the same location, so as to prevent the insulating ring 130 from rotating.

[0024] Also, as described above, in the bearing structure 100 of this embodiment, the caulking portion 136 is provided at the end 130c of the insulating ring. The caulking portion 136 is formed by inserting the insulating ring 130 into the fitting hole 112 of the housing 110 and then caulking (bending and crimping) the end of the insulating ring 130 along the chamfer 114 of the fitting hole 112 using a roller or the like (not shown).

[0025] According to the above configuration, the rotation of the insulating ring 130 with respect to the housing 110 can be suitably prevented. Thereby, even if the outer ring 122 rotates due to creep, the insulating ring 130 does not rotate. That is, even if the alumite film on the inner peripheral surface 130b wears due to creep, the alumite film on the outer peripheral surface 130a does not wear. Therefore, it is possible to maintain good insulation performance for a long time.

[0026] FIG. 3 is a diagram for explaining another example of the bearing structure of the present embodiment, and shows a rotation prevention structure for preventing the rotation of the insulating ring with respect to the housing. For ease of understanding, in other examples of the bearing structure shown in FIGS. 3(a), 3(b), and 3(c), parts other than the housing and the insulating ring are not shown, and members and parts common to the bearing structure 100 of FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

[0027] In the rotation prevention structure illustrated in FIG. 3(a), the housing 210a of the bearing structure 200a has a step portion 214 formed at the edge 212a of the fitting hole 212. The radial width of the step portion 214 changes from width W3 to width W4 in the circumferential direction (W3 < W4) and is non-uniform. In other words, in the bearing structure 200a, an eccentric hole that forms the step portion 214 is provided around the fitting hole 212.

[0028] The insulating ring 230a of the bearing structure 200a has a flange 232 standing from the end of the cylindrical portion 132. Also in this flange 232, the radial width is non-uniform and substantially the same width as the step portion 214 in the circumferential direction. By fitting the flange 232 with the step portion 214, rotation of the insulating ring 230a with respect to the housing 210a can be suitably prevented.

[0029] In the rotation prevention structure illustrated in FIG. 3(b), the housing 210b of the bearing structure 200b is provided with a convex portion 216 at the edge 212a of the fitting hole 212. The insulating ring 230b of the bearing structure 200b has a flange 234 extending along the edge 212a from the end of the cylindrical portion 132, and a fitting hole 234a is formed at a position corresponding to the convex portion 216 of the housing 210b in the flange 234. By fitting the convex portion 216 into the fitting hole 234a, rotation of the insulating ring 230b with respect to the housing 210b can be prevented.

[0030] 3(c), a bearing structure 200c illustrates a case where the thickness of the insulating ring 230c is thicker than that of the insulating ring 230c. In such a case, a D-cut 236 is formed in the insulating ring 230c.

[0031] Meanwhile, a fitting hole 238 is formed in the housing 210c of the bearing structure 200c. Then, with the fixing plate 240 abutting against the fitting hole 212a and the D-cut 236, a pin 242 is fitted into the fitting hole 238 via the fixing plate 240, thereby fixing the insulating ring 230c to the housing 210c. At this time, the fixing plate 240 abuts against the D-cut 236 to restrict the rotation of the insulating ring 230c, so that the rotation of the insulating ring 230c relative to the housing 210c is prevented.

[0032] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Industrial Applicability]

[0033] The present invention can be utilized as an anti-electrolytic corrosion bearing structure including a housing and a bearing attached thereto. [Explanation of symbols]

[0034] 100...bearing structure, 102...shaft, 110...housing, 112...fitting hole, 112a...edge, 114...chamfer, 114a...outer circumference circle, 114b...inner circumference circle, 120...bearing, 122...outer ring, 124...inner ring, 126...rolling element, 130...insulating ring, 130a...outer circumference surface, 130b...inner circumference surface, 130c...end, 130d...end, 132...cylindrical portion, 132a...one end, 134...annular portion, 136...crimping part, 140... disc spring, 150... O-ring, 200a, 200b, 200c... bearing structure, 210a, 210b, 210c... housing, 212... fitting hole, 212a... edge, 214... step part, 216... protrusion, 230a, 230b, 230c... insulating ring, 232... flange, 234... flange, 234a... fitting hole, 236... D-cut, 238... fitting hole, 240... fixing plate, 242... pin

Claims

1. Housing and a bearing mounted to the housing; a cylindrical insulating ring disposed between the housing and the bearing; The insulating ring is made of aluminum or an aluminum alloy and has an anodized aluminum coating formed on its surface.

2. the housing has a fitting hole into which the insulating ring is fitted and a chamfer formed on an edge of the fitting hole, The radial width of the chamfer is non-uniform in the circumferential direction, 2. The bearing structure according to claim 1, wherein the insulating ring has an end formed with a crimped portion that is bent toward the chamfer by crimping.

3. the housing has a fitting hole into which the insulating ring is fitted and a step portion formed on an edge of the fitting hole, The radial width of the step portion is non-uniform in the circumferential direction, 2. The bearing structure according to claim 1, wherein a flange having approximately the same width as the step portion is provided on an end of the insulating ring.

4. A protrusion is provided on the edge of the fitting hole of the housing, A flange is provided on an end of the insulating ring and extends along an edge of the housing, 2. The bearing structure according to claim 1, wherein the flange is formed with a fitting hole into which the protrusion of the housing fits.

5. A D-cut formed in the insulating ring; 2. The electrolytic corrosion prevention bearing structure according to claim 1, further comprising: a fixed plate fixed to the housing and abutting against the D-cut to prevent rotation.

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