JP2007085520A - Ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball bearing, improving the load capacity of a thin bearing, and further giving a sealing function. <P>SOLUTION: In this thin ball bearing, a bearing thickness/bearing outside diameter is set to 0.15 or less to increase the load capacity. The bearing thickness is set to (bearing outside diameter-bearing inside diameter)/2, the ball diameter/bearing thickness is set to 0.5 or more, the bearing thickness/bearing width is set to exceed 0.5, and (ball diameter × number of balls)/(3.14×PCD) is set to 0.5 or more. Further, the bottom of a cage 4 is formed at a folded part 6. Thus, the case bottom of a press iron cage is formed as a folded structure to increase the strength, whereby although it is thin, a small seal member 5 not taking space can be used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ball bearing with improved load bearing performance in a thin bearing.

  For thin ball bearings with a cross-sectional width / bearing outer diameter of 0.15 or less, the ratio of the ball diameter / bearing thickness is less than 0.5 and small balls are used. It was designed to reduce interference. In this case, the ratio of the bearing thickness / bearing width is generally 0.5 or less, and since the ball diameter is small, there is a problem that the load capacity is small.

  Further, when the ratio of the bearing thickness / bearing width exceeds 0.5, it is difficult to mount the cage and the bearing becomes an open type bearing, which causes a problem of grease sealing and dust-proofing of external foreign matter.

  5A and 5B are partial cross-sectional views of ball bearings according to conventional examples. In the conventional example of FIG. 5 (a), both seal types are used, and a ball 3 is interposed between an outer ring 1 and an inner ring 2 so as to be freely rotatable, and includes a cage 4 and seal members 5 and 5. ing. However, it is a thin cage 4 and the width direction is long in order to secure the strength. As a result, the diameter of the ball 3 is small and the bearing width is wide. In the conventional example of FIG. 5B, when the diameter of the ball 3 is increased and the bearing width is decreased, it is difficult to mount the seal member 5 and an open type bearing is obtained.

  However, thin ball bearings are often used for supporting fixing units of copying machines, printers, etc., and in such applications, a relatively large radial load is applied. Since the ball diameter is small, the rated capacity of the ball bearing is small, and the ball bearing is burned out in a short period of time, leading to a problem in life. In addition, bearing seal function is indispensable because it dislikes grease leakage and the external environment is not clean.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a ball bearing capable of improving the load capacity of a thin-walled bearing and further providing a sealing function.

In order to achieve the above object, a ball bearing according to the present invention is a thin ball bearing in which the bearing thickness / outer diameter is 0.15 or less.
The bearing thickness is (bearing outer diameter−bearing inner diameter) / 2.
The ball diameter / bearing thickness is 0.5 or more,
The bearing thickness / bearing width exceeds 0.5, and (ball diameter × number of balls) / (3.14 × PCD) is set to 0.5 or more.

  Preferably, a cage having a sealing function is set on the side opposite to the seal, and the bearing width is reduced.

  Preferably, the retaining ring is set as a seal.

  Further, preferably, a heat insulating bush to be mounted on the inner ring is set as a seal.

  According to the present invention, it is possible to improve the load capacity of the thin bearing, and to provide a sealing function.

  Hereinafter, ball bearings according to embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a partial cross-sectional view of a ball bearing according to a first embodiment of the present invention. The ball bearing is of a double seal type, a ball 3 is interposed between the outer ring 1 and the inner ring 2 so as to be freely rotatable, and includes a cage 4 and seal members 5 and 5.

  In a thin ball bearing in which the bearing thickness / bearing outer diameter is 0.15 or less to increase the load capacity, the bearing thickness is (bearing outer diameter−bearing inner diameter) / 2, The bearing thickness is 0.5 or more, the bearing thickness / bearing width is more than 0.5, and (ball diameter × number of balls) / (3.14 × PCD) is 0.5 or more. It is set. Thus, the ball diameter is large and has a large number of balls. Therefore, by maximizing the ball diameter and the number of balls, a high load capacity can be achieved, and in particular, a long life can be achieved at a heavy load portion such as an office machine fixing portion.

  Further, the bottom of the cage 4 is formed in the folded portion 6. By making the bottom of the pressed iron cage a folded structure and increasing the strength, it is possible to use a small seal member 5 that does not take up space even if it is thin. In addition, since the bottom portion of the cage 4 is the folded portion 6, sufficient strength can be obtained even with the cage 4 made of a thin iron plate.

  By forming the shape of the bottom portion of the cage 4 in the folded portion 6 and also serving as a sealing function, it is possible to omit a bearing space necessary for attaching the seal, to design a small width, and to reduce the cost.

(Second Embodiment)
FIG. 2A is a partial cross-sectional view of a ball bearing according to a second embodiment of the present invention, FIG. 2B is an enlarged cross-sectional view of a folded portion of a cage, and FIG. It is a fragmentary sectional view of the ball bearing which concerns on the modification of embodiment.

  In the present embodiment of FIG. 2A, the seal member on the back side of the seal is removed, and the back shape of the cage 4 is formed in the folded portion 6 so that it also serves as a seal function. A seal member 5 is mounted on the opposite side.

  With these shapes, the cage 4 and the seal member 5 do not interfere with each other even in a small bearing having a bearing thickness / bearing width ratio exceeding 0.5.

  In this case, the center of the ball 3 can be shifted in the axial direction to be asymmetric. By shifting the center of the ball 3 with respect to the axial direction (shifting the center of the ball 3 in the back direction of the cage 4 also serving as a sealing function), a ball bearing having a thinner width can be designed.

  In the modification of FIG. 2C, a retaining ring 7 is set on the outer diameter side of the outer ring 1.

(Third embodiment)
FIG. 3A is a partial cross-sectional view of a ball bearing according to a third embodiment of the present invention, and FIG. 3B is a side view of a seal and retaining ring.

  In the bearing with a retaining ring according to the present embodiment, the retaining ring 8 also serves as a sealing function.

  Thus, by using the collar surface of the retaining ring 8 also as a bearing seal, a space for attaching the seal becomes unnecessary, so that the bearing width can be reduced. Cost can be reduced by eliminating the need for a seal.

The retaining ring 8 also serving as a seal is provided with a notch 9 as shown in FIG.
(Fourth embodiment)
FIG. 4A is a partial cross-sectional view of a ball bearing according to a fourth embodiment of the present invention, and FIG. 4B is a side view of a heat-insulating bush for sealing.

  In the present embodiment, the heat insulating bush 10 also serves as a sealing function in the bearing with the heat insulating bush. As a result, a sealing function can be obtained even for a bearing having a small bearing width / bearing width ratio exceeding 0.5.

  By using the flange surface of the heat-insulating bush 10 also as a bearing seal, a space for attaching the seal becomes unnecessary, so that the bearing width can be reduced. Cost can be reduced by eliminating the need for a seal.

  Note that the heat insulating bush 10 also serving as a seal is provided with a notch 11 as shown in FIG.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.

  Table 1 shows a list of dimensions of Comparative Examples 1 to 3 and Examples 1 to 7. Note that the retaining ring 8 and the heat insulating bush 10 are applicable regardless of the form of the drawing.

It is a fragmentary sectional view of the ball bearing concerning a 1st embodiment of the present invention. (A) is a fragmentary sectional view of the ball bearing which concerns on 2nd Embodiment of this invention, (b) is an expanded sectional view of the folding | returning part of a holder | retainer, (c) is 2nd Embodiment. It is a fragmentary sectional view of the ball bearing which concerns on the modification of a form. (A) is a fragmentary sectional view of the ball bearing which concerns on 3rd Embodiment of this invention, (b) is a side view of a retaining ring for a seal. (A) is a fragmentary sectional view of the ball bearing concerning a 4th embodiment of the present invention, and (b) is a side view of a heat insulating bush for seal. (A) (b) is a fragmentary sectional view of the ball bearing which concerns on a prior art example, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Inner ring 3 Ball 4 Cage 5 Seal member 6 Folding part 7 Retaining ring 8 Retaining ring for sealing 9 Notch part 10 Insulating bush for sealing 11 Notch part

Claims (4)

In a thin ball bearing having a bearing thickness / outer diameter of 0.15 or less,
The bearing thickness is (bearing outer diameter−bearing inner diameter) / 2.
The ball diameter / bearing thickness is 0.5 or more,
A ball bearing characterized in that the bearing thickness / bearing width exceeds 0.5, and (ball diameter × number of balls) / (3.14 × PCD) is set to 0.5 or more.   The ball bearing according to claim 1, wherein a cage having a sealing function is set on the side opposite to the seal, and the bearing width is reduced.   The ball bearing according to claim 1, wherein the retaining ring is set as a seal.   The ball bearing according to any one of claims 1 to 3, wherein the heat insulating bush mounted on the inner ring is set as a seal.

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