JP2005133817A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing 1 in which seal grooves provided in an outer ring 2 or an inner ring 3 made of ceramics have a shape that can be easily and quickly processed for reducing production cost. <P>SOLUTION: The cross sectional shape in the width direction of the seal grooves 2b, 2c in the outer ring 2 made of ceramics is a shallow partial circular arc. Seal members 6 are engaged with the seal grooves 2b, 2c. If the seal grooves 2b, 2c are like that, the shape of a grinding tool is made to have the same shape as the seal grooves 2b, 2c so that processing can be performed with only grinding processing by pushing the grinding tool on the outer ring 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rolling bearing having a ceramic ring.

When mounting a seal member on a ceramic raceway ring, for example, the seal member is fitted into a flat shoulder on the raceway side peripheral surface of the raceway, or fitted into a seal groove formed on the shoulder. (For example, refer to Patent Document 1). In this case, the seal groove has the same shape as a seal groove provided on a general metal raceway ring, that is, the diameter is gradually increased from the end edge in the axial direction toward the raceway side, and the groove depth is deep and a relatively acute angle. It is a perfect corner shape.
JP-A-11-247864 (FIG. 8)

  In the above conventional example, the shape of the seal groove of the ceramic raceway is the same as the shape of the seal groove of a general metal raceway. Connected.

  The present invention provides a rolling bearing in which a plurality of rolling elements are interposed between an outer ring and an inner ring, and at least one of the two rings is made of ceramics. A seal groove having a partial arc shape in cross section is provided, and a peripheral portion of a resin seal member is fitted into the seal groove.

  The rolling elements include balls and various types of rollers. The sealing member includes any type of non-contact and contact. The sealing member also includes a composite body having a resin member, such as a member formed of resin alone, a body made of resin, and a lip attached to the body made of an elastic body such as rubber.

  According to the present invention, since the cross-sectional shape of the seal groove is a partial arc, the seal groove can be easily and quickly formed only by a polishing process that presses a polishing grindstone, for example. When the seal groove is a substantially arc, since there are no corners such as sharp corners, polishing is easier, shape accuracy is improved, and processing costs can be reduced. However, the shape of this grinding wheel is preferably the same as the shape of the seal groove. Since the seal member is attached to the seal groove in a state of being slightly compressed in the radial direction, it is difficult to come out of the seal groove, and the fitting portion with the seal groove has a partially arc, so that the posture standing upright in the radial direction Thus, the wearing state is stabilized and the sealing performance is improved.

  It is preferable that the rolling elements are balls, each raceway portion of the outer ring and the inner ring is formed in a groove shape, and the maximum depth of the seal groove is set smaller than the maximum depth of the raceway portion. This is because grooving is easy.

  The seal member is opposed to one shoulder portion of the raceway portion of the other wheel through a minute gap, and the axial width t2 of the fitting portion to the seal groove is set to 1 of the axial width t1 of the portion facing the other wheel. It is preferable that the minimum thickness of the seal member is set to be larger than the axial width t1. Since the deformation of the seal member is suppressed and the posture is stabilized, the sealing performance can be further improved.

  According to the present invention, since the seal groove can be easily formed on the one wheel by polishing using a polishing grindstone or the like instead of cutting, the manufacturing cost of the rolling bearing can be reduced. Further, since the seal member can be attached in a stable posture, the sealing performance of the rolling bearing can be improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a cross section of the upper half of a rolling bearing, and FIG. FIG.

  The illustrated rolling bearing 1 is a deep groove ball bearing type, and includes an outer ring 2, an inner ring 3, a plurality of rolling elements (balls) 4, and a cage 5. At both ends in the axial direction between the outer ring 2 and the inner ring 3, annular seal members 6 and 6 are incorporated. The bearing internal space is sealed by both seal members 6 and 6, and a lubricant such as grease or oil is sealed in the bearing internal space.

  The outer ring 2 is provided with a groove-like raceway portion 2a in the middle of the inner peripheral surface in the axial direction, and seal grooves 2b and 2c are provided on both shoulder portions in the axial direction of the raceway portion 2a. The inner ring 3 is provided with a groove-like track portion 3a in the middle of the outer peripheral surface in the axial direction, and both shoulder portions in the axial direction of the track portion 3a are formed flat. The rolling elements 4 are disposed between the track portions 2a and 3a and are held by the cage 5 at substantially equal intervals in the circumferential direction. The cage 5 may be a crown type or any other type.

  The outer peripheral edge portions of the seal members 6 and 6 are fitted in the seal grooves 2 b and 2 c of the outer ring 2. The inner peripheral edge portions of the seal members 6 and 6 are opposed to the shoulder portions at both ends in the axial direction on the outer peripheral surface of the inner ring 3 via a minute gap.

  Both the outer ring 2 and the inner ring 3 of the present invention are made of ceramics. In this case, only the outer ring 2 may be made of ceramics. The rolling element 4 is optional such as made of ceramics or bearing steel. Examples of the ceramic include silicon nitride ceramics, silicon carbide ceramics, alumina ceramics, and zirconia ceramics. The seal member 6 is made of a resin such as a fluorine-based resin or engineering plastics. The rolling bearing 1 having such a configuration is suitable for use in an environment where a corrosive gas exists or in an environment where a nonmagnetic material is required.

  The shape of the seal grooves 2b and 2c of the outer ring 2 and the seal member 6 will be specifically described.

  The seal grooves 2b and 2c of the outer ring 2 have a partial arc in the cross-sectional shape along the width direction. The magnitude | size of this partial arc should just be below a semicircular arc. Further, a single arc or a combination of arcs having different diameters may be used as long as the curve approximates an arc, that is, a substantially arc. With the seal grooves 2b and 2c having such a shape, the shape of the polishing grindstone is the same as the shape of the seal grooves 2b and 2c, and the seal grooves 2b and 2c are formed only by the polishing process of pressing the polishing grindstone against the ceramic outer ring 2. Processing can be done easily and quickly.

  The seal member 6 is preferably a body portion 6a having a uniform width from the inner peripheral edge to the middle of the outer diameter side, and a fitting portion 6b having an outer diameter side wider than the body portion 6a. ing. The fitting portion 6b protrudes only inward of the bearing as a form in which the inside of the body portion 6a is recessed in the width direction along the radial direction. Due to the protruding shape of the fitting portion 6b, mutual interference between the seal member 6 and the cage 5 is suppressed, and the amount of lubricant enclosed in the bearing internal space can be increased as much as possible. The cross-sectional shape in the width direction of the fitting portion 6b is the partial arc so that the fitting portion 6b fits into the groove inner surfaces of the seal grooves 2b and 2c without any gap and fits into the seal grooves 2b and 2c.

The dimensions of the seal grooves 2b, 2c and each part of the seal member 6 will be described.
In the seal grooves 2b and 2c, the maximum depth a is set to be smaller than the maximum depth of the raceway portion 2a of the outer ring 2, and the axial direction (width) dimension b is ¼ or less of the axial total length B of the outer ring 2. The curvature radius R1 is set to be not less than 5 times and not more than 30 times the depth a.

  In the sealing member 6, the width t2 of the fitting portion 6b is set to 0.025 times or more of the diameter D of the sealing member 6 and 1.2 times or more of the width t1 of the body portion 6a. The minimum thickness is set larger than the width dimension t1, and the curvature radius R2 is set to be the same as the curvature radius R1 of the seal grooves 2b and 2c. In this case, the axial width b of the seal grooves 2b and 2c is preferably set in consideration of the widths of both shoulder portions of the track portion 2a.

  As described above, the sealing grooves 2b and 2c of the ceramic outer ring 2 have a simple shape of a cross-section arc, and the depth thereof is shallower than the depth of the track portion 2a. Can contribute to reducing manufacturing costs. In addition, since the seal member 6 is mounted in the seal grooves 2b and 2c in a state of being slightly compressed in the radial direction, the seal member 6 is not easily pulled out of the seal grooves 2b and 2c, and the seal grooves 2b and 2c and the seal member 6 are fitted. Due to the relationship that the joint portion 6b is a partial arc, the sealing member 6 is stabilized in an upright posture in the radial direction, and the clearance between the sealing member 6 and the inner ring 3 can be accurately managed. Can contribute.

  As shown in FIG. 3, each outer end side of the seal grooves 2b, 2c (only one seal groove 2b is shown) of the outer ring 2 is made smaller than the diameter dimension at the maximum depth position of the seal grooves 2b, 2c. The diameter may be expanded by. In this case, it becomes easy to attach the seal member 6 to the seal grooves 2b and 2c.

  Furthermore, as shown in FIG. 4, the seal member 6 can have a shape such that the body portion 6 a is gradually narrowed from the fitting portion 6 b side toward the inner peripheral edge and the inner side surface is a tapered slope. . In this case, the rigidity of the sealing member 6 itself is improved as compared with that shown in FIG. 1, deformation such as warpage is less likely to occur, and the sealing performance is improved.

  The rolling bearing of the present invention can also be applied to double-row ball bearings and single-row or double-row roller bearings.

The figure which shows the cross section of the upper half of the rolling bearing which concerns on the best form of this invention The figure which expands and shows the principal part of FIG. Sectional drawing which shows the other form of the seal groove of an outer ring | wheel The figure which shows the other form of a sealing member

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rolling bearing 2 Outer ring 2a Track part 2b, 2c Seal groove 3 Inner ring 3a Track part 4 Rolling body 6 Seal member 6a Body part 6b Fitting part

Claims (3)

In a rolling bearing in which a plurality of rolling elements are interposed between an outer ring and an inner ring, and at least one of the two rings is made of ceramics,
A seal groove having a substantially arc-shaped cross-section in the width direction is provided on the shoulder portion of the raceway portion of the one wheel, and a peripheral portion of a resin seal member is fitted in the seal groove. Rolling bearing.   The rolling element is a ball, and each raceway portion of both wheels is formed in a groove shape, and the maximum depth of the seal groove is set smaller than the maximum depth of the raceway portion. The rolling bearing according to 1.   The seal member is opposed to one shoulder portion of the raceway portion of the other of the two wheels via a minute gap, and the axial width t2 of the fitting portion to the seal groove is that of the portion facing the other wheel. The rolling bearing according to claim 1 or 2, wherein the rolling bearing is set to 1.2 times or more of the axial width t1 and the minimum thickness of the seal member is set to be larger than the axial width t1. .

Images