JP2005188526A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press-formed rolling bearing having improved fittability to a shaft while maintaining the advantage of lower manufacturing cost. <P>SOLUTION: The rolling bearing comprises an inner ring 1, an outer ring 2, a plurality of balls 3 arranged therebetween, and a cage 4 for holding the balls 3. The inner ring 1 and the outer ring 2 are both press-formed. A circumferential uneven pattern 11 is formed on the inner diameter of the inner ring 1 by press punching work. The degree of unevenness is 1%-20% of a raceway bottom plate thickness which is determined by ((the raceway bottom diameter of the inner ring)-(the inner diameter))/2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rolling bearing, and more particularly to a rolling bearing in which an inner ring and an outer ring (or only an inner ring) are formed by press molding.

A rolling bearing in which an inner ring and an outer ring are formed by press molding is described in, for example, Patent Document 1, but a conventional bearing has a cylindrical surface with a smooth inner ring inner diameter.
JP-A-7-248018

  The rolling bearing has an advantage that the manufacturing cost is low. However, when the rolling bearing is used for inner ring rotation, it is necessary to fit completely tight in order to prevent creep between the inner ring and the shaft. On the other hand, the inner ring formed by press molding has a problem that the tolerance of the inner diameter is large in manufacturing, so that it does not fit completely tight or the interference is too large and breaks. It was.

  An object of the present invention is to provide a press-molded rolling bearing that maintains the advantage of low manufacturing cost and has improved fitting with a shaft.

  A rolling bearing according to the present invention has an inner ring, an outer ring, and rolling elements, and in a rolling bearing in which at least the inner ring is formed by press molding, the inner ring inner diameter is formed with unevenness in the circumferential direction by press punching. It is characterized by this.

  The unevenness of the inner ring is formed simultaneously with the press molding. The concavo-convex shape is not particularly limited, but it is preferable that the cross-sectional shape is corrugated or formed by knurling for ease of processing. The center diameter of the inner ring inner diameter is set so that the inner ring inner diameter becomes the tightest fit with the shaft even when the inner ring inner diameter is the largest, considering the tolerance range of press molding, and the inner ring inner diameter is a smooth cylindrical surface. Same or slightly smaller than

  The inner ring is fixed to a rotating shaft such as a motor shaft, and the outer ring is fixed to a motor case or the like. Usually, the inner ring is subjected to heat treatment, and the shaft (rotary shaft) is not subjected to heat treatment.

  In the above-mentioned rolling bearing, it is preferable that the concavo-convex shape is corrugated from the viewpoint of achieving both ease of press forming and ease of press-fitting.

  Moreover, it is preferable that the amount of unevenness (the difference between the distance from the center of the inner ring to the top surface of the convex part and the distance from the center of the inner ring to the bottom surface of the concave part) is 1% or more and 20% or less of the track bottom plate thickness. Here, the track bottom plate thickness is determined by the track bottom plate thickness = (track bottom diameter of inner ring−inner diameter) / 2. If the track bottom plate thickness is less than 1%, the effect of stress relaxation at the time of press-fitting is small, and if it exceeds 20%, there is a risk of unevenness on the track surface of the inner ring. The unevenness is more preferably 1% or more and 10% or less of the track bottom plate thickness.

  According to the rolling bearing of the present invention, since the inner ring inner diameter is formed with unevenness in the circumferential direction, even when the inner ring inner diameter is the largest within the tolerance range of press molding, the inner ring and the shaft are fitted tightly, Even when the inner ring inner diameter is the smallest within the tolerance range of press molding, the stress applied to the entire inner ring is relieved, and damage to the inner ring during press-fitting is prevented. Moreover, since the convex part of the inner ring is engaged with the shaft, it is advantageous for preventing creep.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 show an embodiment of a rolling bearing according to the present invention. In the following description, the left and right refer to the left and right in FIG.

  The rolling bearing includes an inner ring (1), an outer ring (2), a ball (3) that is a plurality of rolling elements arranged therebetween, and a cage (4) that holds the ball (3).

  For example, the inner ring (1) is fixed to a rotating shaft such as a motor shaft, and the outer ring (2) is fixed to a motor case.

  Both the inner ring (1) and the outer ring (2) are formed by press molding, and the inner ring (1) includes a spherical part (1a) including the raceway surface of the ball (3) and a right side of the spherical part (1a). And the outward flange portion (1c) provided on the left side of the spherical surface portion (1a). The outer ring (2) is provided on the left side of the spherical part (2b), the spherical part (2a) including the raceway surface of the ball (3), the cylindrical part (2b) provided on the left side of the spherical part (2a). Inward flange portion (2c).

  FIG. 2 is a view as seen from the direction A in FIG. 1. As shown in FIG. 2, the inner ring (1) has an inner diameter (11) formed by press punching to form circumferential irregularities (11). Yes. The shape of the unevenness (11) is corrugated, and this processing is performed simultaneously with the press processing for forming the inner ring (1) into the above shape.

  The amount of unevenness (11), that is, the difference between the distance from the center of the inner ring (1) to the tip of the convex part (11a) and the distance from the center of the inner ring (1) to the bottom of the concave part (11b) is 1% or more and 20% or less of the track bottom plate thickness obtained by (track bottom diameter−inner diameter) / 2, more preferably 1% or more and 10% or less of the track bottom plate thickness. Further, the amount of the unevenness (11) is 0.02% or more and 4% or less of the inner ring (1) inner diameter as a reference.

FIG. 1 is a longitudinal sectional view showing an embodiment of a rolling bearing according to the present invention. FIG. 2 is a view as seen from the direction A in FIG.

Explanation of symbols

(1) Outer ring
(2) Inner ring
(3) Ball (rolling element)
(11) Unevenness
(11a) Convex
(11b) Recess

Claims (3)

A rolling bearing having an inner ring, an outer ring and a rolling element, wherein at least the inner ring is formed by press molding, the inner ring inner diameter is formed with unevenness in the circumferential direction by press punching. . The rolling bearing according to claim 1, wherein the uneven shape is corrugated. The rolling bearing according to claim 1 or 2, wherein the unevenness is 1% or more and 20% or less of the track bottom plate thickness.

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