JP2007205555A - Insulated bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed insulated bearing with increased insulation performance. <P>SOLUTION: This insulated ball bearing comprises an inner ring serving as a race and an outer ring 23 having an insulation film 23a, balls serving as rolling elements arranged between the inner ring and the outer ring 23, a retainer holding the balls at intervals, and sealing seals 26 disposed on both end surfaces of the inner ring and the outer ring 23. The outer ring 23 has chamfered parts 23c at corners facing the sealing seals 26. An insulation film 23a is formed on the outer ring to cover the outer diameter surface, both end surfaces, and chamfered parts 23c. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an insulated bearing, and more particularly to an insulated bearing used for a railway vehicle main motor.

  Conventionally, cylindrical roller bearings and deep groove ball bearings have been used as bearings used in railway vehicle main motors. For example, a ball bearing 1 as shown in FIG. 4 includes an inner ring 2, an outer ring 3, a ball 4 as a rolling element disposed between the inner ring 2 and the outer ring 3, and a cage 5 that holds a gap between the balls 4. And a hermetic seal 6 disposed between the inner ring 2 and the outer ring 3.

  Moreover, the ball bearing 1 used for a railway vehicle main motor is an insulating bearing in which an insulating coating 3a is formed on the outer diameter surface and both end surfaces of the outer ring 3 in order to prevent damage to the bearing due to electrolytic corrosion. The insulating coating 3a is formed by spraying an insulating material such as ceramics.

  In addition, since the railway vehicle main motor is used outdoors, there is a concern that grease may deteriorate due to dust contamination in an open type bearing in which a grease pocket is formed in the bearing peripheral structure. Therefore, it is preferable to use a sealed bearing in order to prevent the grease from being deteriorated due to dust and to extend the maintenance cycle.

  However, in the case of the ball bearing 1 configured as described above, since the bearing internal space volume is small, there is a problem that an appropriate amount of grease cannot be sealed to ensure the bearing life necessary for the railway vehicle main motor bearing. . This problem applies to roller bearings as well.

  As a means to solve the above problem, it is conceivable to increase the filling ratio of the grease with respect to the internal space volume. In this case, however, the agitation resistance of the grease increases at the time of rotation of the bearing, particularly at the start, and the temperature of the bearing rapidly increases. Is not appropriate.

  Therefore, in a sealed bearing, an insulated bearing capable of ensuring an appropriate amount of grease inside the bearing is described in, for example, Japanese Patent Application Laid-Open No. 2004-346972 (Patent Document 1).

As shown in FIG. 5, the cylindrical roller bearing 11 described in the publication has an inner ring 12, an outer ring 13, a cylindrical roller 14 disposed between the inner ring 12 and the outer ring 13, and the interval between the cylindrical rollers 14. A retainer 15 to be held and sealing seals 16 disposed at both axial ends of the inner ring 12 and the outer ring 13 are provided, and the outer diameter surface and both end surfaces of the outer ring 13 are covered with an insulating coating 13a. Further, the sealing seal 16 has a U-shape projecting from both end faces of the inner ring 12 and the outer ring 13, and is fixed to the outer ring 13 by a stopper 16a.
JP 2004-346972 A

  When the ball bearing 1 shown in FIG. 4 is fixed to the housing 7, a predetermined shoulder height h is required as shown in FIG. Therefore, when the ball bearing 1 is small, the lower end of the housing 7 and the outer ring 3 are separated from each other by the thickness of the insulating coating 3 a of the outer ring 3.

  At this time, the creeping distance between the outer ring 3 and the housing 7 becomes the thickness δ of the insulating coating 3a at the lower end of the insulating coating 3a, and is very small. Further, since the outer ring 3 and the housing 7 are conductors such as metal, if a potential difference of a certain level or more occurs between the housing 7 and the outer ring 3, creeping discharge is generated along the lower end of the insulating coating 3a, and the ball bearing 1 May be damaged by electric corrosion. In the present specification, “creeping discharge” refers to a phenomenon in which discharge occurs along the surface of the insulating coating when a certain potential difference or more occurs on both sides of the insulating coating.

  Accordingly, an object of the present invention is to provide a sealed insulation bearing having further improved insulation performance.

  The insulated bearing according to the present invention includes a bearing ring having an insulating coating and a resin sealing member held by the bearing ring. The bearing ring has a chamfered portion at a corner facing the sealing member, and the chamfered portion is covered with an insulating coating.

  In the insulated bearing having the above configuration, the creeping distance at the end face of the raceway ring is increased by the axial length of the chamfered portion, so that the insulation performance of the bearing is improved. At this time, by setting the axial length of the chamfered portion to 1 mm or more, the chamfered portion can be used as a bearing that supports the rotating shaft of the railway vehicle main motor.

  Preferably, the creepage distance defined by the axial length of the insulating coating located on the corner of the raceway is 1 mm or more. Thereby, even if it uses in the environment where a big electric potential difference arises between peripheral structures, such as a railway vehicle main motor, and a bearing, the insulated bearing which can avoid the damage by electrolytic corrosion can be obtained.

  Preferably, the sealing member protrudes from both end faces of the inner ring and outer ring as the races with a substantially U-shaped cross-sectional shape. In the sealing member configured as described above, the inside of the protruding portion functions as a grease pocket. Thereby, an insulated bearing capable of enclosing an appropriate amount of grease inside the bearing can be obtained.

  Preferably, the sealing member has a convex portion at an end abutting against the raceway, and the raceway has a concave portion that receives the convex portion. Thereby, a sealing member can be reliably fixed to a bearing ring. Further, the sealing member can be easily attached.

  According to the present invention, by providing a chamfered portion at a corner portion facing the sealing member of the bearing ring, a creepage distance necessary for avoiding electrolytic corrosion can be ensured, so that an insulating bearing having excellent insulating performance is obtained. be able to.

  With reference to FIGS. 1-3, the ball bearing 21 which concerns on one Embodiment of this invention is demonstrated.

  As shown in FIG. 2, the ball bearing 21 includes an outer ring 23 having an inner ring 22 and an insulating film 23 a as raceways, a ball 24 as a rolling element disposed between the inner ring 22 and the outer ring 23, It is an insulated bearing provided with a cage 25 for holding a gap, and a sealing seal 26 as a resin sealing member that protrudes from both axial ends of the inner ring 22 and the outer ring 23 in a U-shaped cross section.

  As shown in FIG. 1, the outer ring 23 has a chamfered portion 23 c at a corner portion facing the hermetic seal 26. Further, the insulating coating 23a is formed so as to cover the outer diameter surface, both end surfaces, and the chamfered portion 23c. The insulating coating 23a is formed by spraying an insulating material such as ceramics.

In the ball bearing 21 of the above-described configuration, the creepage distance on the corners of the outer ring 23, ₁ the thickness of the insulating coating 23a [delta], when the axial width of the chamfered portion 23c and _{w 1,} represented by [delta] ₁ + _{w 1} . The creepage distance is set to 1 mm or more. Thereby, even when used in an environment where a large potential difference occurs between a peripheral member such as a railway car main motor and the bearing, the ball bearing 21 capable of avoiding damage to the bearing due to electrolytic corrosion can be obtained.

  In the present specification, the “creeping distance” refers to the minimum distance along the surface of the insulating member sandwiched between two conductors, and is insulated on the corner of the outer ring 23 shown in FIG. It is defined by the axial length of the coating 23a.

  The hermetic seal 26 has a grease pocket inside the substantially U-shaped protrusion, and can seal an appropriate amount of grease inside the bearing. Moreover, since it is formed of a resin material having high insulation performance, there is less risk of lowering the insulation performance of the bearing compared to a hermetic seal containing a highly conductive metal.

  In this specification, the “substantially U-shaped” is not limited to the U-shaped shape such as the sealing seal 26 shown in FIG. Any shape that protrudes from this part shall be included.

  Further, the sealing seal 26 has a convex portion 26a at an end that contacts the outer ring 23, and the outer ring 23 has a concave portion 23b that receives the convex portion 26a on its inner diameter surface. Since the convex portion 26a and the concave portion 23b are fitted and fixed when the sealing seal 26 is assembled, the sealing seal 26 can be easily and securely attached as compared with the case where the sealing seal 26 is fixed using a stopper or the like. Is possible.

  Note that when an insulating material is sprayed onto the outer ring 23 having the above-described configuration, as shown in FIG. 3, the insulating coating 23a formed on the chamfered portion 23c is thicker than the other portions (shaded portion). This portion may be left as it is, or may be removed by machining or the like so that the thickness becomes uniform.

  Moreover, a standard product can be used for the inner ring 22 in the ball bearing 21 having the above-described configuration. Thereby, it becomes possible to suppress the cost increase of a product. Furthermore, since the labyrinth structure by the peripheral members can be simplified by using the sealed bearing, the motor can be reduced in size and weight.

  In the above embodiment, an example in which the chamfered portion 23c is c chamfered as shown in FIG. 1 has been shown. It suffices if the corner part is retracted in the axial direction from the end face.

  In the above embodiment, an example of a ball bearing having an insulating coating on the outer diameter surface and both end surfaces of the outer ring has been shown. However, the present invention is not limited thereto, and an insulating coating is formed on the inner diameter surface and both end surfaces of the inner ring. It is good as well. Since the inner ring inner surface has a smaller spray area than the outer ring outer surface, the thermal spraying cost can be reduced by spraying the insulating material onto the inner ring inner surface.

  In the above embodiment, an example of the inner ring rotating type bearing in which the seal seal 26 is fixed to the outer ring 23 is shown. However, the present invention is not limited to this, and the present invention is not limited to this. It can also be applied to type bearings.

  Further, in the above-described embodiment, an example in which the sealing seal 26 protrudes from the end surfaces of the inner ring 22 and the outer ring 23 is shown, but the present invention is not limited to this, and the present invention protrudes from the end surfaces of the inner ring 22 and the outer ring 23. It can also be applied to rolling bearings with standard seals that do not.

  Furthermore, although the example of the ball bearing 21 was shown in said embodiment, it is not restricted to this, A cylindrical roller bearing, a tapered roller bearing, a self-aligning roller bearing, a deep groove ball bearing, a 4-point contact ball bearing, an angular contact It can be applied to rolling bearings such as ball bearings and any other insulated bearings.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention is advantageously used for an insulating bearing used in a railway vehicle main motor or the like.

It is a figure which shows the principal part of this invention, Comprising: It is an enlarged view of the Q section of FIG. It is a figure showing a ball bearing concerning one embodiment of this invention. It is a figure which shows the state before the finishing process of the Q section of FIG. It is a figure which shows the conventional standard roller bearing. It is a figure which shows the example of the roller bearing which made the seal seal protrude from the end surface of an inner ring | wheel and an outer ring | wheel, and enlarged the bearing internal space. It is an enlarged view of the P section in FIG.

Explanation of symbols

  1,21 Ball bearing, 2,12,22 Inner ring, 3,13,23 Outer ring, 3a, 13a, 23a Insulating coating, 23b Recess, 23c Chamfered part, 4,24 Ball, 5,15,25 Cage, 6, 16, 26 Seal, 16a Stopper, 26a Convex, 7 Housing, 11 Cylindrical roller bearing, 14 Cylindrical roller.

Claims (4)

A bearing ring having an insulating coating;
In an insulating bearing provided with a resin sealing member held by the bearing ring,
The bearing ring has a chamfered portion at a corner facing the sealing member,
The insulating bearing, wherein the chamfered portion is covered with the insulating coating.   2. The insulated bearing according to claim 1, wherein a creepage distance defined by an axial length of an insulating coating located on a corner of the raceway is 1 mm or more.   3. The insulated bearing according to claim 1, wherein the sealing member protrudes from both end faces of an inner ring and an outer ring as the races with a substantially U-shaped cross-sectional shape. The sealing member has a convex portion at an end contacting the raceway,
The said bearing ring is an insulated bearing in any one of Claims 1-3 which has a recessed part which receives the said convex part.

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