JP2013050139A - Ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball bearing inhibiting a grease bridge from being formed between a bearing ring and a retainer.SOLUTION: A width T of the retainer 6 in a bearing radial direction is set at 53-57% of a distance L in the bearing radial direction between the outer peripheral surface 2b of an inner ring 2 and the inner peripheral surface 3a of an outer ring 3, and grease of an amount which is 40-50% of a bearing space volume is filled in a bearing space. With this, a grease bridge is prevented from being formed between the bearing ring 4 and the retainer 6. As a result, rotational torque can be reduced and fluctuations of the rotational torque can be decreased.

Description

  The present invention relates to a ball bearing in which grease is sealed in a bearing.

  A ball bearing in which grease is sealed in a bearing is incorporated in, for example, a fan motor of a home air conditioner that requires high energy saving performance. The grease sealed in the bearing is composed of a thickener, a base oil, and an additive. Such greases are semi-solid due to the nature of the thickener. The semi-solid property of the grease becomes the rotational resistance of the ball bearing, which increases the rotational torque of the ball bearing. Therefore, in the ball bearing described in Patent Document 1, the amount of grease enclosed is 15% to 25% of the bearing space volume. Thereby, the stirring resistance of grease can be reduced and the rotational torque of the ball bearing can be reduced.

JP 2004-84771 A

By the way, in a ball bearing in which grease is sealed in the bearing, it is known that when a grease bridge is formed between the bearing ring (inner ring and outer ring) and the retainer, the stirring resistance of the grease increases and the rotational torque varies. ing. In other words, if the formation of the grease bridge can be suppressed, the performance of the ball bearing can be further improved.
Therefore, the present invention has been made in view of the above circumstances, and has been made as an object to provide a ball bearing capable of suppressing the formation of a grease bridge between a race ring and a retainer. is there.

  In order to solve the above-mentioned problems, a ball bearing according to the present invention includes a ring formed of an inner ring and an outer ring, and an annular retainer that is provided between the inner ring and the outer ring and holds a plurality of rolling elements. And a grease sealed between the inner ring and the outer ring, wherein the cage has a width T in the bearing radial direction, the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. It is characterized by being set to 53% to 57% of the distance L in the radial direction of the bearing.

  ADVANTAGE OF THE INVENTION According to this invention, the ball bearing which can suppress that a grease bridge is formed between a bearing ring and a retainer can be provided.

It is explanatory drawing for showing the width T of the retainer in the bearing radial direction and the distance L in the bearing radial direction between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. It is the table | surface which compared the rotational torque of the ball bearing of this invention, and the rotational torque of the ball bearing of a prior art. It is the perspective view which cut and showed the typical ball bearing partially. It is a perspective view which shows a typical retainer.

An embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 3, the ball bearing 1 includes a raceway ring 4 constituted by an inner ring 2 and an outer ring 3, and a plurality of balls 5 (rolling elements) provided between the inner ring 2 and the outer ring 3. And an annular retainer 6 (retainer). On the outer peripheral surface 2b of the inner ring 2 and the inner peripheral surface 3a of the outer ring 3, a raceway surface on which each ball 5 rolls is formed along the circumferential direction. Further, the ball bearing 1 is used for closing the openings on both sides in the bearing axial direction (left and right direction in FIG. 3) of the space 7 formed between the outer peripheral surface 2b of the inner ring 2 and the inner peripheral surface 3a of the outer ring 3. It has a pair of sealing plates 8 and 9.

  As shown in FIG. 4, the retainer 6 is a so-called crown-shaped cage, and is obtained by molding a resin material such as polyamide resin or POM (eg, polyacetal). The retainer 6 has a spherical ball pocket 10 that holds a plurality (ten in the form of FIG. 4) of the balls 5 at equal intervals in the circumferential direction. Note that the resin material is not limited to the above resin material, and for example, a glass material, a carbon fiber, or the like may be contained mainly with a moldable resin material. 3 and 4 merely show typical examples of the ball bearing 1 and the retainer 6, respectively, and these drawings are not intended to limit the shapes of the ball bearing 1 and the retainer 6.

  1, the width T of the retainer 6 in the bearing radial direction (also the radial direction of the inner ring 2 and the outer ring 3) is a bearing between the outer peripheral surface 2b of the inner ring 2 and the inner peripheral surface 3a of the outer ring 3. It is set to 53% to 57% of the distance L in the radial direction. In other words, the width T in the bearing radial direction of the retainer 6 is set to 53% to 57% of the width L in the bearing radial direction of each opening on both sides in the bearing axial direction of the space 7. The retainers 6 may be arranged so as to be evenly allocated to the inner ring 2 side and the outer ring 3 side with respect to the pitch circle diameter (PCD) of the ball bearing 1, and the pitch of the ball bearing 1 may be changed as necessary. It can be biased toward the inner ring 2 side or the outer ring 3 side with respect to the circular diameter.

  Then, the bearing space of the ball bearing 1 includes the volume of the bearing 5, that is, the volume of the space 7 formed between the inner ring 2, the outer ring 3, and the pair of sealing plates 8, 9. Grease (not shown) in an amount of 40% to 50% of the volume obtained by subtracting the total volume of the total volume and the volume of the retainer 6 is enclosed. The composition of the grease can be appropriately selected according to required characteristics (low torque property, high speed property, heat resistance, etc.).

Next, the operation of this embodiment will be described.
FIG. 2 shows the rotational torque of a conventional ball bearing (hereinafter referred to as a conventional product if necessary) and the improved ball bearing 1 of the present invention (hereinafter referred to as an improved product if necessary). It is the chart which compared rotational torque. Here, the conventional product and the improved product are small-diameter ball bearings having an outer diameter of 22 mm incorporated in the air conditioner motor, but are not intended to be limited to this.
In addition, each bearing space of the conventional product and the improved product is filled with grease in an amount of 40% to 50% of each bearing space volume. Further, the conventional product and the improved product are ball bearings having an outer diameter of 22 mm, an inner diameter of 8 mm, and a ball diameter of 3.9688 mm, respectively, and other dimensions are as shown in Table 1 below.

  As can be understood from Table 1, in the improved product, the width T of the retainer 6 (retainer) is 0.2 mm smaller (thinner) than the conventional product. Thereby, in the improved product, the distance from the outer diameter (outer peripheral surface 2b) of the inner ring 2 to the inner diameter (inner peripheral surface 6a) of the retainer 6 is increased by 23% compared to the conventional product. Further, in the improved product, the distance from the inner diameter (inner peripheral surface 3a) of the outer ring 3 to the outer diameter (outer peripheral surface 6b) of the retainer 6 is increased by 30% compared to the conventional product.

  As a result, as shown in FIG. 2, the average rotational torque of the conventional product is about 1500 μNm, whereas the average rotational torque of the improved product is about 1000 μNm. In comparison, the rotational torque is reduced by 30% or more. In addition, in the standard deviation (σ) of the rotational torque, the improved product is 1/2 or less of the conventional product, and the improved product has a greatly improved variation in rotational torque compared to the conventional product.

  Thus, in the improved product (the ball bearing 1 of the present invention), the distance between the race ring 4 and the retainer 6, in particular, the distance between the inner ring 2 and the retainer 6 is increased compared to the conventional product, and Even when grease having an amount of 40% to 50% of the bearing space volume is sealed in the bearing space, a grease bridge (applied between the inner ring 2 and the retainer 6, particularly between the inner ring 2 and the retainer 6) It is possible to prevent the formed grease from being partially or wholly connected between the retainer and the inner ring and between the retainer and the outer ring. As a result, in the improved product, the stirring resistance of the grease is reduced as compared with the conventional product. Thereby, the rotational torque is reduced and the variation of the rotational torque is reduced. In particular, the reason why it is effective to increase the distance between the inner ring 2 and the retainer 6 is that the relative speed between the retainer 6 and the inner ring 2 during the rotation of the ball bearing 1, particularly in the case of two rotations of the inner ring. This is because the relative speed between the retainer 6 and the outer ring 3 is about twice that of the retainer 6 and the stirring resistance is increased.

This embodiment has the following effects.
According to the present embodiment, the width T in the bearing radial direction of the retainer 6 is set to 53% to 57% of the distance L in the bearing radial direction between the outer peripheral surface 2b of the inner ring 2 and the inner peripheral surface 3a of the outer ring 3. Then, even if grease of an amount 40% to 50% of the bearing space volume is sealed in the bearing space by increasing the distance between the race ring 4 and the retainer 6, particularly the distance between the inner ring 2 and the retainer 6. The formation of a grease bridge between the race ring 4 and the retainer 6, particularly between the inner ring 2 and the retainer 6, is suppressed. As a result, the ball bearing 1 of the present invention can reduce the agitation resistance of the grease as compared with the conventional product, can reduce the rotational torque and can reduce the variation of the rotational torque.
Further, as in Patent Document 1, it is possible to reduce the torque and secure a long life of the operation time without reducing the amount of grease filled to 25% or less.
The present invention is more effective when applied to a small-diameter ball bearing having an outer diameter of the outer ring of 22 mm or less.

  And by adopting the ball bearing 1 of this invention for the motor for an air-conditioner, the energy-saving property of an air-conditioner and silence can be improved.

In addition, embodiment is not limited above, For example, it can comprise as follows.
In this embodiment, the ball bearing 1 is configured by providing a pair of sealing plates 8 and 9 on both sides in the bearing axial direction of the space 7 formed between the outer peripheral surface 2 b of the inner ring 2 and the inner peripheral surface 3 a of the outer ring 3. However, one or both of the pair of sealing plates 8 and 9 can be omitted as necessary.

1 ball bearing, 2 inner ring, 3 outer ring, 4 race ring, 5 ball (rolling element), 6 retainer (retainer)

Claims (6)

A raceway ring constituted by an inner ring and an outer ring, a ring-shaped cage provided between the inner ring and the outer ring and holding a plurality of rolling elements, and grease sealed between the inner ring and the outer ring A ball bearing including:
The cage is
A ball bearing characterized in that a width T in the bearing radial direction is set to 53% to 57% of a distance L in the bearing radial direction between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. The ball bearing according to claim 1, wherein the cage is a crown-shaped cage. The ball bearing according to claim 1, wherein the cage is made of a material mainly composed of a moldable resin. A pair of sealing plates for closing the openings on both sides in the bearing axial direction of the space formed between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring;
The grease is
40% of the bearing space volume obtained by subtracting the total volume of the plurality of rolling elements and the volume of the cage from the space volume formed between the inner ring, the outer ring, and the pair of sealing plates. The ball bearing according to any one of claims 1 to 3, wherein an amount of -50% is enclosed. The ball bearing according to claim 1, wherein an outer diameter of the outer ring is 22 mm or less. The ball bearing according to claim 1, wherein the ball bearing is incorporated in an air conditioner motor.