JP2008281017A - Anti-electrolytic corrosion rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost anti-electrolytic corrosion rolling bearing easily securing dimensional accuracy, and high in heat radiation efficiency. <P>SOLUTION: A structure having an inner ring 1, an outer ring 2, a roller 3 incorporated between the inner ring 1 and the outer ring 2, and a cage 4 holding the roller 3, and formed by applying blasting to an outer peripheral surface 5 of the outer ring 2 and an axial end surface 6 thereof, and further applying electrostatic coating of an epoxy resin thereto is used for this anti-electrolytic corrosion rolling bearing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric corrosion-preventing rolling bearing in which an insulating coating is formed on the surface of a raceway to prevent electrical corrosion of the raceway.

  In general, bearings that support the axles of railway vehicles and bearings incorporated in rotating machines such as motors and generators are used to prevent electric corrosion of the race rings. A bearing is used. This electric corrosion-preventing rolling bearing prevents the current from flowing from the periphery of the bearing into the bearing with the insulating coating of the raceway ring, so that no spark is generated between the raceway and the rolling element, and electroerosion occurs on the raceway ring. Absent.

As such an electric corrosion prevention rolling bearing, there are known ones in which an insulating coating on the surface of the race is formed by thermal spraying of ceramics (Patent Documents 1 and 2) and those formed by injection molding of PPS resin.
JP 2002-48145 A Japanese Utility Model Publication No. 2-46119

  However, when an insulating coating is formed by spraying ceramics on the surface of the raceway, the raceway may be deformed by the heat of spraying. In particular, when the bearing is small, since the race is thin, the race is easily deformed by the heat of spraying, and it is difficult to ensure the dimensional accuracy of the bearing.

  Further, when an insulating film is formed by injection molding of PPS resin on the surface of the race, it is necessary to manufacture an injection molding mold, which is expensive. In addition, it is difficult to form a thin insulating film by injection molding, and the film thickness of the insulating film is generally 0.5 mm or more. Therefore, when an insulating film is formed by injection molding PPS resin on the surface of the raceway, The heat dissipation efficiency from the bearing was low.

  The problem to be solved by the present invention is to provide an electric corrosion prevention rolling bearing which is easy to ensure dimensional accuracy, is low in cost and has high heat dissipation efficiency.

  In order to solve the above-mentioned problem, an inner ring, an outer ring, a rolling element incorporated between the inner ring and the outer ring, and a cage for holding the rolling element, the outer circumferential surface of the outer ring and the axial direction A structure in which the end surface is blasted and electrostatic coating of epoxy resin is applied to the electric corrosion prevention rolling bearing.

  In addition, the electric corrosion-preventing rolling bearing can be subjected to blast treatment on the inner peripheral surface and the axial end surface of the inner ring, and can further be subjected to electrostatic coating of epoxy resin.

  In the electric corrosion-preventing rolling bearing according to the present invention, since the insulating coating of the outer ring is formed by electrostatic coating, the outer ring is hardly thermally deformed when the insulating coating is formed, and the dimensional accuracy of the bearing is easily secured. In addition, the electric corrosion prevention rolling bearing is low in cost because it does not require a molding die for forming an insulating film. Furthermore, since this electric corrosion prevention rolling bearing forms an insulating film by electrostatic coating, it can form a thin insulating film and has high heat dissipation efficiency.

  In addition, since the erosion-preventing rolling bearing of the present invention is blasted before the electrostatic coating is applied, the adhesion of the insulating coating to the outer ring is large, and the insulating coating is unlikely to peel off.

  In addition, the inner peripheral surface and the axial end surface of the inner ring are subjected to a blasting process, and an epoxy resin electrostatic coating is applied to one of the inner ring insulating film and the outer ring insulating film. Even if peeling occurs, the other insulating coating prevents intrusion of current into the bearing, so that it is excellent in reliability of preventing electrolytic corrosion.

  FIG. 1 shows an electric corrosion prevention rolling bearing according to an embodiment of the present invention. This electric corrosion prevention rolling bearing includes an inner ring 1, an outer ring 2, a roller 3 incorporated between the inner ring 1 and the outer ring 2, and a cage 4 that holds the roller 3.

  As for the outer ring | wheel 2, the insulating film 7 is formed in the outer peripheral surface 5 and the axial direction end surface 6 by the electrostatic coating of the epoxy resin. Further, the outer peripheral surface 5 and the axial end surface 6 of the outer ring 2 are roughened by subjecting the substrate before electrostatic coating to blasting, whereby the outer peripheral surface 5 and the axial end surface 6 of the outer ring 2 are roughened. This improves the adhesion of the insulating coating 7 to the surface and prevents the insulating coating 7 from peeling off.

  In the electric corrosion prevention rolling bearing configured as described above, the insulating coating 7 of the outer ring 2 prevents current from flowing from the periphery of the bearing into the bearing. Therefore, no spark is generated between the outer ring 2 and the roller 3 and between the inner ring 1 and the roller 3, and no electrolytic corrosion occurs on the outer ring 2 and the inner ring 1.

  Further, in this electric corrosion prevention rolling bearing, since the insulating coating 7 of the outer ring 2 is formed by electrostatic coating, the outer ring 2 is not easily thermally deformed when the insulating coating 7 is formed even when the outer ring 2 is thin. Therefore, it is easy to ensure the dimensional accuracy of the bearing even when the bearing is small.

  In addition, this electric corrosion prevention rolling bearing does not require a molding die for forming the insulating coating 7, so that the cost is low.

  Furthermore, since this electric corrosion prevention rolling bearing forms the insulating coating 7 by electrostatic coating, it is possible to form a thinner insulating coating 7 as compared with the case where the insulating coating 7 is formed by injection molding. By setting the film thickness of the coating 7 to 0.5 mm or less, the heat dissipation efficiency of the bearing can be ensured. The insulating coating 7 is preferably formed so as to have a thickness of 0.2 mm or more. Thereby, the breakdown voltage of the insulating coating 7 can be ensured.

  In the above embodiment, only the outer ring 2 out of the outer ring 2 and the inner ring 1 is electrostatically coated with epoxy resin, but the electrostatic coating of epoxy resin may be performed on both the outer ring 2 and the inner ring 1. For example, the inner peripheral surface 8 and the axial end surface 9 of the inner ring 1 can also be subjected to blasting, and further, electrostatic coating of epoxy resin can be performed. In this way, even if one of the insulating coatings of the inner ring 1 and the outer coating of the outer ring 2 is peeled off, the other insulating coating prevents the current from entering the bearing. The reliability of prevention is improved.

  In the above embodiment, a cylindrical roller bearing is exemplified. However, the present invention is applicable to other types of rolling bearings such as a deep groove ball bearing, an angular ball bearing, a self-aligning ball bearing, and a tapered roller bearing. Can be applied.

  The relationship between the film thickness of the insulating coating and the breakdown voltage was examined for the product of the present invention and the conventional product. FIG. 2 shows the relationship. The actual product is obtained by applying an electrostatic coating of epoxy resin to the outer peripheral surface of the outer ring (inner diameter 35 mm, outer diameter 40 mm, width 12 mm) to form an insulating coating. Further, the conventional product is obtained by spraying ceramic on the outer peripheral surface of an outer ring (inner diameter 35 mm, outer diameter 40 mm, width 12 mm) to form an insulating coating.

  As a result, the breakdown voltage when the film thickness was 0.2 mm was 4 kV or more, and it was confirmed that the implemented product had an insulation performance equivalent to that of the conventional product (breakdown voltage 3 kV).

The partially expanded sectional view which shows the electric corrosion prevention rolling bearing of embodiment of this invention The figure which shows the relationship between the film thickness of an insulation film, and a breakdown voltage about the implementation product of this invention, and a conventional product

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Roller 4 Cage 5 Outer peripheral surface 6 Axial end surface 7 Insulating coating 8 Inner peripheral surface 9 Axial end surface

Claims (2)

  Inner ring (1), outer ring (2), rolling element (3) incorporated between inner ring (1) and outer ring (2), and cage (4) for holding the rolling element (3) And an outer surface (5) and an axial end surface (6) of the outer ring (2) are subjected to blasting, and further subjected to electrostatic coating of epoxy resin to prevent galvanic corrosion.   2. The electrolytic corrosion-preventing rolling bearing according to claim 1, wherein the inner peripheral surface (8) and the axial end surface (9) of the inner ring (1) are subjected to blasting and further electrostatically coated with epoxy resin.

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