JP2021025613A - Deep groove ball bearing - Google Patents

Abstract

To provide a deep groove ball bearing that can reduce slide friction between a ball and a retainer even when the ball has a contact angle by being applied with pre-load.SOLUTION: A deep groove ball bearing includes: an outer ring; an inner ring; multiple balls disposed between raceway surfaces of the outer ring and the inner ring; and a retainer including multiple cylindrical or oblong cylindrical pockets for respectively storing the multiple balls and guided by the outer ring or inner ring. The pocket has an inner surface that is formed while being inclined in an axial direction of the deep groove ball bearing relative to a flat surface that is perpendicular to a bearing center axis.SELECTED DRAWING: Figure 1

Description

The present invention relates to deep groove ball bearings, and can be used, for example, in applications such as dental air turbines, vacuum cleaners, turbochargers, etc., which rotate at a high speed ^{of 10000 min-1 or more.}

As a conventional deep groove ball bearing, one using a cage guided by an inner ring or an outer ring and having a cylindrical pocket having a cylindrical inner surface is known (see, for example, Patent Document 1). In such a cylindrical pocket, an extension of the central axis of the pocket extends along the radial direction of the cage (ie, parallel to the plane perpendicular to the bearing central axis and passes through the bearing central axis). It is generally formed as follows.

Jitsukaisho 56-49315

By the way, in a deep groove ball bearing, when a preload in the axial direction is applied to the bearing, the ball comes into contact with the raceway surface with a contact angle. Therefore, when the ball rotates, the traveling portion of the ball has a cylindrical shape. It contacts the inner surface of the pocket while having an inclination of the contact angle with respect to the pocket. Therefore, the position of the ball in contact with the cylindrical pocket is separated from the rotation axis, the ball comes into contact with the inner surface of the pocket at a place where the rotation peripheral speed is high, and the sliding friction between the ball and the cage increases. For this reason, the rotational torque increases, and heat generation between the ball and the cage causes a concern that the grease life is shortened and the cage is worn.

The present invention has been made in view of the above circumstances, and provides a deep groove ball bearing capable of reducing sliding friction between a ball and a cage even when the ball has a contact angle by applying a preload. The purpose is.

The above object of the present invention is achieved by the following configuration.
(1) With the outer ring
Inner ring and
A plurality of balls arranged between the raceway surfaces of the outer ring and the inner ring, and
A cage having a plurality of cylindrical or long-cylindrical pockets, each of which accommodates the plurality of balls, and guided by the outer ring or the inner ring.
It is a deep groove ball bearing equipped with
A deep groove ball bearing in which the inner surface of the pocket is formed so as to be inclined in the axial direction of the deep groove ball bearing with respect to a plane perpendicular to the bearing center axis.
(2) The deep groove ball bearing according to (1), wherein the predetermined tilt angle at which the pocket is tilted in the axial direction is the same as the contact angle of the ball in a state where a preload is applied.
(3) The deep groove ball bearing according to (1) or (2), wherein the cage is a crown type cage.

According to the deep groove ball bearing of the present invention, even when the ball has a contact angle by applying a preload, the contact angle of the ball with respect to the plane perpendicular to the bearing center axis in the direction in which the pocket is tilted in the axial direction. By making the direction equal to the tilting direction, the sliding friction between the ball and the cage can be reduced. As a result, it is possible to reduce the rotational torque, reduce the heat generation between the ball and the cage, extend the grease life associated therewith, reduce the cage wear, and reduce the cage vibration.

It is sectional drawing of the deep groove ball bearing which concerns on 1st Embodiment of this invention. (A) is a perspective view of the cage of FIG. 1, and (b) is a cross-sectional view of the cage of (a). (A) is a schematic view showing a state in which a ball contacts the pocket in a general cage in which the central axis of the pocket extends along the radial direction, and (b) is a schematic view showing a state in which the central axis of the pocket is axially oriented. It is a schematic diagram which shows the state which a ball comes into contact with a pocket in the cage of this embodiment which extends tilted. 3A is a diagram showing a ball and a general cage for explaining a running portion of the ball when the ball has a contact angle in the cage of FIG. 3A, and FIG. 3B is a diagram of FIG. 3A. It is a figure which shows the pocket of a ball and a cage as seen from the arrow VI. It is sectional drawing of the deep groove ball bearing which concerns on the modification of 1st Embodiment of this invention. (A) is a perspective view of the cage of FIG. 5, and (b) is a cross-sectional view of the cage of (a). It is sectional drawing which shows the cage of the deep groove ball bearing which concerns on 2nd Embodiment of this invention.

Hereinafter, deep groove ball bearings according to each embodiment of the present invention will be described with reference to the drawings.

(First Embodiment)
As shown in FIG. 1, the deep groove ball bearing 10 of the present embodiment has an outer ring 11 having a raceway surface 11a on the inner peripheral surface, an inner ring 12 having a raceway surface 12a on the outer peripheral surface, and raceway surfaces of the outer ring 11 and the inner ring 12. A plurality of balls 13 arranged between 11a and 12a, and a crown-shaped cage 20 for rotatably holding the balls 13 are provided.

The outer ring 11 includes a pair of shoulder portions 11b and 11c on both sides of the raceway surface 11a in the axial direction, and the inner ring 12 also includes a pair of shoulder portions 12b and 12c on both sides of the raceway surface 12a in the axial direction. Further, the raceway surface 11a of the outer ring 11 and the raceway surface 12a of the inner ring 12 are both formed symmetrically with respect to the plane P perpendicular to the bearing center axis X passing through the center O of the ball 13.

The crown-shaped cage 20 is formed with a plurality of cylindrical pockets 30 in which a part 31 is open in the axial direction, which accommodates the plurality of balls 13, at predetermined intervals in the circumferential direction. Further, the cage 20 is provided on the inner peripheral surface of the shoulder portions 11b and 11c of the outer ring 11 and on any one or more surfaces of the shoulder portions 12b and 12c of the inner ring 12 (in the present embodiment, the shoulder portion 12c of the inner ring 12). You are being guided.

Further, in the deep groove ball bearing 10, a mounting groove 11d is formed on the shoulder portion 11b of the outer ring 11 on the side opposite to the side where the annular portion 22 of the cage 20 is located with respect to the center O of the ball 13. The shield member 40 is fixed to the mounting groove 11d by using an elastic ring 41.

The material of the cage 20 is arbitrary, and may be made of metal or resin. The resin cage 20 is made of a synthetic resin material such as a polyamide resin, a polyacetal resin, a polyphenylene sulfide, a polyetheretherketone, or a polyimide, and is manufactured by injection molding or cutting. In addition, glass fiber, carbon fiber, aramid fiber and the like may be added to the resin material as a reinforcing material.

Here, each pocket 30 of the cage 20 of the present embodiment is tilted in the axial direction of the deep groove ball bearing 10 at a predetermined tilt angle θ with respect to the plane P perpendicular to the bearing central axis X.
That is, as shown in FIG. 2B, the deep groove ball bearing has an extension line L of the central axis of the cylindrical pocket 30 at a predetermined inclination angle θ with respect to a plane P perpendicular to the bearing central axis X. It is tilted in the axial direction of 10 and passes through the bearing central axis X. It is assumed that the central axis of the cage 20 coincides with the bearing central axis X.

As shown in FIG. 1, the deep groove ball bearing 10 of the present embodiment is subjected to an axial load as shown by an arrow F to apply a preload, so that the ball 13 has a contact angle α and the raceway surface 11a. , 12a. The contact angle α is defined as an angle formed by a plane P perpendicular to the bearing central axis X and an action line connecting two contact points where the ball 13 contacts the outer ring 11 and the inner ring 12, respectively.

Therefore, as described below, the direction in which the cylindrical pocket 30 is tilted in the axial direction with respect to the plane P perpendicular to the bearing central axis X is equal to the direction in which the contact angle α of the ball 13 is tilted. By installing the deep groove ball bearing 10, the sliding friction between the ball 13 and the cage 20 caused by the contact angle α is reduced. Further, in the present embodiment, preferably, the predetermined inclination angle θ of the pocket 30 is set to be the same as the contact angle α of the ball 13 in the state where the preload is applied.

As shown in FIG. 3A, in the case of a general cage 100 in which the extension line L of the central axis of the pocket 30 extends along the radial direction of the cage 20, the ball 13 is at a point P1 away from the rotation axis. And the inner surface of the pocket 30 come into contact with each other, so that the ball 13 and the inner surface of the pocket 30 come into contact with each other at a place where the rotation peripheral speed is high.

On the other hand, as shown in FIG. 3B, in the case of the cage 20 of the present embodiment in which the predetermined inclination angle θ of the pocket 30 and the contact angle α of the ball 13 are the same, the point P2 on the rotation axis. The ball 13 and the inner surface of the pocket 30 come into contact with each other, and the ball 13 and the inner surface of the pocket 30 can be brought into contact with each other at a position where the rotation peripheral speed is relatively smaller than that of the cage 100 in FIG. 3 (a). it can.

As a result, the sliding friction between the ball 13 and the pocket 30 of the cage 20 can be reduced, the rotational torque is reduced, the heat generation between the ball 13 and the cage 20 is reduced, the grease life is extended, and the cage is worn. Reduction and reduction of cage vibration can be realized.

Depending on the usage conditions, if the ball behaves differently from the rotation axis, the rotation axis may not always be orthogonal to the contact angle α. Therefore, the rotation peripheral speed as shown in FIG. 3 (b). In the sense that the ball 13 and the inner surface of the pocket 30 are brought into contact with each other at a small location, the predetermined inclination angle θ of the pocket 30 and the contact angle α of the ball 13 do not necessarily have to be the same.

Further, in the case of the cage 100 of a general cylindrical pocket instead of the spherical pocket, as shown in FIG. 4, the contact between the ball 13 and the cylindrical pocket 30 when viewed from the running portion of the ball 13. The gap between the parts will be different on the left and right. Therefore, the lubrication of the inner surfaces of the ball 13 and the pocket 30 becomes unstable, and there is a possibility that the cage 100 may vibrate or the rotation balance may be lost.
In the present embodiment, by tilting the extension line L of the central axis of the pocket 30 in the axial direction, the balance between the left and right clearances becomes uniform, so that a good lubrication state in the pocket 30 of the cage 20 can be maintained. You can expect it.

The radial clearance (radius) between the inner peripheral surface of the outer ring 11 and the guide portion of the cage 20 is 1 to 4% of the ball diameter, and the inner diameter of the pocket 30 is 1.03 to 1.2 times the ball diameter. By doing so, even in the cage 20 of the present embodiment, vibration is less likely to occur in the cage 20, so that the high-speed rotation performance can be more reliably satisfied.

As described above, according to the deep groove ball bearing 10 of the present embodiment, the pocket 30 of the cage 20 is the deep groove ball bearing at a predetermined inclination angle θ with respect to the plane P perpendicular to the bearing central axis X. Since it is tilted in the axial direction of 10, even if the ball 13 has a contact angle α by applying a preload, the direction in which the pocket 30 is tilted in the axial direction is directed with respect to the plane P perpendicular to the bearing central axis X. By making the contact angle α of the ball 13 equal to the tilting direction, the sliding friction between the ball 13 and the cage 20 can be reduced. As a result, it is possible to reduce the rotational torque, reduce the heat generation between the ball 13 and the cage 20, extend the grease life associated therewith, reduce the cage wear, and reduce the cage vibration.

When the direction in which the axial load is applied is opposite to that in the above embodiment as in the modified examples shown in FIGS. 5 and 6, the contact angle α of the cage 20a is the bearing central axis X. The inner surface of the pocket 30a may be tilted in the axial direction in the same direction as the plane P perpendicular to the plane P.

(Second Embodiment)
In the deep groove ball bearing of the second embodiment, as shown in FIG. 7, the pocket 30b has an elongated cylindrical shape (that is, the cross section is composed of a combination of a semicircle and a straight line) having a part opened in the axial direction. It is applied to the crown type cage 20b having. The cage 20b may also be an outer ring guide, an inner ring guide, or an inner / outer ring guide.

Again, the pocket 30 b of the retainer 20b, to the perpendicular plane P to the bearing central axis X, at a predetermined inclination angle theta, since inclined in the axial direction of the deep groove ball bearing, applying a preload As a result, even when the ball 13 has a contact angle, the sliding friction between the ball 13 and the cage 20b can be reduced.
Further, by forming the pocket 30b having a long cylindrical shape, it is possible to prevent the force of the ball 13 from being applied in the circumferential direction of the cage 20b.

The present invention is not limited to the above-described embodiment, and can be appropriately modified or improved.
For example, the number of pockets in the cage and the number of balls do not necessarily have to match.
Further, the cage of the present invention is not limited to the crown-type cage of the present embodiment, and may be applied to any type of cage.
Further, the deep groove ball bearing of the present invention is not limited in bearing size and internal specifications.

10, 10a Deep groove ball bearing 11 Outer ring 11a Race surface 12 Inner ring 12a Race surface 13 Ball 20, 20a, 20b Crown type cage 30, 30a Cylindrical pocket 30b Long cylindrical pocket α Contact angle θ Tilt angle

Claims (3)

With the outer ring
Inner ring and
A plurality of balls arranged between the raceway surfaces of the outer ring and the inner ring, and
A cage having a plurality of cylindrical or long-cylindrical pockets, each of which accommodates the plurality of balls, and guided by the outer ring or the inner ring.
It is a deep groove ball bearing equipped with
A deep groove ball bearing in which the inner surface of the pocket is formed so as to be inclined in the axial direction of the deep groove ball bearing with respect to a plane perpendicular to the bearing center axis. The deep groove ball bearing according to claim 1, wherein the predetermined tilt angle at which the pocket tilts in the axial direction is the same as the contact angle of the ball in a state where a preload is applied. The deep groove ball bearing according to claim 1 or 2, wherein the cage is a crown type cage.

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