JP2017020616A - Four-point ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a four-point ball bearing which can elongate a life by preventing multi-point contact between an outer ring raceway groove and balls at a high-speed operation.SOLUTION: An outside rest angle αo which is formed of a linear line A for connecting a contact point between a ball 3 and an outer ring raceway groove 1a when the ball 3 is pressed against the outer ring raceway groove 1a and a ball center O, and a bearing center line C is smaller than an inside rest angle αi which is formed of a linear line B for connecting a contact point between the ball 3 and an inside raceway groove 2a, and the ball center O when the ball 3 is pressed against the inside raceway groove 2a. In addition to this, a contact angle α1 at a load side is smaller than a contact angle α2 at a non-load side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a four-point contact ball bearing, and more particularly to a four-point contact ball bearing used for a pump, a compressor, and the like.

  Conventionally, a four-point contact ball bearing is known as a single row ball bearing that receives an axial load and a radial load from both sides in the axial direction. As shown in FIG. 6, in the four-point contact ball bearing 100, generally, a plurality of balls 103 are predetermined in the circumferential direction by a cage 104 between an outer ring 101 and two inner rings 102 divided in the axial direction. It is held so as to roll freely at intervals of. On the inner peripheral surface of the outer ring 101 and the outer peripheral surface of the inner ring 102, an outer ring raceway groove 101a and an inner ring raceway groove 102a are formed by two circular arc surfaces 101a1, 101a2, 102a1, and 102a2 having different centers of curvature, respectively.

  As the conventional four-point contact ball bearing 100, the four-point contact ball bearing 100 having the same contact angles β1 and β2 on both the load side and the anti-load side is used. As a result, the same bearing performance is exhibited regardless of whether the axial load is supported on the load side or the anti-load side.

  Further, as a conventional four-point contact ball bearing, the inner ring raceway surface and the outer ring raceway surface are different on both sides in the axial direction by making the curvature radii different from each other in the axial direction with respect to the bearing center or making the contact angles different from each other. One having an arc surface is known (for example, see Patent Document 1). In Patent Document 1, the inner ring raceway surface and the outer ring raceway surface are designed to have different circular arc surfaces on both sides in the axial direction, so that even when a pure radial load is applied, the ball always causes a spin motion and prevents poor lubrication. ing.

JP 2002-21855 A

  By the way, when the four-point contact ball bearing 100 is used for a pump or a compressor, the direction in which the load is mainly received is constant, and the load is supported on the anti-load side only when an anti-thrust load is generated when the device is stopped. Is required.

  Here, when rotating at a high speed with an axial load applied, the ball 103 is pressed against the outer diameter side of the outer ring by receiving a centrifugal force from a state in which contact is made only at two points on the load side. Therefore, the ball 103 moves along the outer ring raceway groove 101a in the ball moving direction (upper right direction in the figure) in FIG. 6 and approaches the outer ring opposite load side, and a change occurs such that the contact angle β1 on the inner ring load side increases. . When the ball 103 approaches the anti-load side of the outer ring 101, contact between the anti-load side arcuate surface 101a2 and the ball 103 occurs. The angle at which the outer ring 101 and the ball 103 contact at this time corresponds to a rest angle (outer ring side rest angle).

  In this state, since the rotation direction of the ball 103 and the rotation direction of the outer ring 101 on the opposite load side are different, the contact of the ball 103 at both contact points between the two circular arc surfaces 101 a 1 and 101 a 2 of the outer ring raceway groove 101 a and the ball 103. Since the peripheral speeds at the parts are different, slipping occurs, wear and heat generation increase, and bearing damage may occur at an early stage.

  The four-point contact ball bearing described in Patent Document 1 is premised on the use by contact at four points, and there is no description about the relationship between the contact angle and the load condition in the axial direction. In some cases, slipping occurs and wear and heat generation increase, leading to bearing damage early.

  The present invention has been made in view of the above-described problems, and its purpose is to suppress contact between the ball and the outer ring raceway groove on the anti-load side in high speed operation, and can be stably operated over a long period of time. The object is to provide a contact ball bearing.

The above object of the present invention can be achieved by the following constitution.
(1) an outer ring having an outer ring raceway groove formed on the inner peripheral surface;
An inner ring having an inner ring raceway groove formed on the outer peripheral surface;
A plurality of balls arranged to roll freely between the outer ring raceway groove and the inner ring raceway groove;
A cage for holding the plurality of balls in a circumferential direction at a predetermined interval;
Have
In a stationary state, when the ball is pressed in the radial direction, the ball is a four-point contact ball bearing that contacts the outer ring raceway groove and the inner ring raceway groove at two points,
A four-point contact ball bearing characterized in that the outer ring side rest angle is smaller than the inner ring side rest angle.
(2) an outer ring having an outer ring raceway groove formed on the inner peripheral surface;
An inner ring having an inner ring raceway groove formed on the outer peripheral surface;
A plurality of balls arranged to roll freely between the outer ring raceway groove and the inner ring raceway groove;
A cage for holding the plurality of balls in a circumferential direction at a predetermined interval;
Have
In a stationary state, when the inner and outer rings are pressed in the thrust direction, the ball is a four-point contact ball bearing that contacts the outer ring raceway groove and the inner ring raceway groove with a contact angle,
A four-point contact ball bearing characterized in that the contact angle on the non-load side is larger than the contact angle on the load side.
(3) The four-point contact ball bearing according to (1), wherein the outer ring raceway groove diameter on the anti-load side is larger than the outer ring raceway groove diameter on the load side.

  The outer ring side rest angle and the inner ring side rest angle are angles at which the ball contacts the outer ring raceway groove or the inner ring raceway groove when the ball is pressed in the radial direction in a stationary state. The contact angle is an angle at which the outer ring raceway groove and the inner ring raceway contact when the outer ring and the inner ring are pressed in the axial direction.

  According to the four-point contact ball bearing of the present invention, the outer ring side rest angle is smaller than the inner ring side rest angle. Therefore, even if the outer ring raceway groove and the ball are By preventing multi-point contact, premature bearing damage due to sliding can be prevented, and a long life can be achieved.

  Also, the contact angle on the anti-load side is larger than the contact angle on the load side, so even if it is used at high speed rotation with an axial load applied, it prevents multiple contact between the outer ring raceway groove and the ball. As a result, early bearing damage due to sliding can be prevented, and a long life can be achieved.

It is sectional drawing of the 4-point contact ball bearing which concerns on 1st Embodiment of this invention. It is sectional drawing of the four-point contact ball bearing shown in FIG. 1 with which the axial load was loaded. It is sectional drawing of the 4-point contact ball bearing which concerns on 2nd Embodiment of this invention. It is a principal part enlarged view which shows the outer ring raceway groove | channel and outer ring side rest angle of the 4-point contact ball bearing shown in FIG. FIG. 4 is a cross-sectional view of the four-point contact ball bearing shown in FIG. 3 in which an axial load is applied. It is sectional drawing of the conventional 4-point contact ball bearing.

  Hereinafter, each embodiment of the four-point contact ball bearing according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIGS. 1 and 2, the four-point contact ball bearing 10 of this embodiment has a single outer ring 1 having an outer ring raceway groove 1a on the inner peripheral surface and an inner ring raceway groove 2a on the outer peripheral surface. A plurality of balls 3 that are arranged between the outer ring 1 and the inner ring 2 so as to be freely rollable at a predetermined interval between the inner ring 2 that is divided into two in the axial direction at an axially intermediate portion, And an outer ring guide type retainer 4 for retaining the balls 3 at predetermined intervals in the circumferential direction. The outer ring raceway groove 1a and the inner ring raceway groove 2a are respectively formed by two arcuate surfaces 1a1, 1a2, 2a1, 2a2 having different centers of curvature.

Here, in the four-point contact ball bearing 10 of the present embodiment, the ball 3 and the outer ring when the ball 3 and the outer ring raceway groove 1a are relatively moved in the radial direction and the ball 3 is pressed against the outer ring raceway groove 1a. An angle formed by a straight line A connecting the contact point with the raceway groove 1a and the ball center O and a bearing centerline C extending radially through the ball center O is an outer ring side rest angle αo, and the ball 3 and the inner ring raceway groove 2a. Between the contact point between the ball 3 and the inner ring raceway groove 2a and the center of the ball when the ball 3 is pressed against the inner ring raceway groove 2a. If the angle formed is the inner ring side rest angle αi, the outer ring side rest angle αo is set smaller than the inner ring side rest angle αi. Specifically, the circular arc surfaces 1a1 and 1a2 of the outer ring raceway groove 1a are bilaterally symmetrical without changing the groove curvature and the groove diameter, and the groove center shift amount on the outer ring 1 side (the axial shift amount of the curvature center). ) Is small.
The circular arc surfaces 2a1, 2a2 of the inner ring raceway groove 2a are also formed symmetrically with respect to the bearing center line C extending in the radial direction through the center of the ball.

  As a result, as shown in FIG. 2, even when the axial load Fa is applied and used at high speed rotation, the clearance S between the circular arc surface 1a2 on the side opposite to the outer ring and the ball 3 is increased, and centrifugal force This prevents the ball 3 from coming into contact with the outer ring raceway groove 1a (arc surface 1a2) on the anti-load side. Therefore, it is possible to prevent the outer ring raceway groove 1a and the balls 3 from hitting multiple points, prevent early bearing damage due to slipping, and achieve a long life.

  In the four-point contact ball bearing 10 of the first embodiment, when the outer ring side rest angle αo is smaller than the inner ring side rest angle αi, the axial backlash becomes large. In applications such as pumps, it is necessary to set the inner ring side rest angle αi to be large and adjust the axial clearance to an optimum value. For example, αi−αo = 0.1 ° to 3 ° is preferable.

(Second Embodiment)
As shown in FIGS. 3 to 5, the four-point contact ball bearing 10 of the present embodiment has an outer ring raceway on the anti-load side in addition to making the outer ring side rest angle αo smaller than the inner ring side rest angle αi. By increasing the groove diameter of the groove 1a (arc surface 1a2), the contact angle α2 on the anti-load side is made larger than the contact angle α1 on the load side. As a result, the clearance on the load side is reduced as much as possible, and the clearance S between the arcuate surface 1a2 on the outer ring opposite load side and the ball 3 is increased. Therefore, the increase in play in the axial direction is minimized, and two hits between the ball 3 and the outer ring 1 (outer ring raceway groove 1a) when the centrifugal force acts on the ball 3 during high-speed rotation are suppressed.
In the present embodiment, the circular arc surfaces 2a1 and 2a2 of the inner ring raceway groove 2a are formed symmetrically with respect to the bearing center line C extending in the radial direction through the ball center.

  Here, the internal design of the four-point contact ball bearing 10 is represented by Expression (1).

但し、αは、接触角、Ｄａは、玉３の直径、ｒｉは、内輪軌道溝の溝径（円弧面の曲率半径）、ｒｅは、外輪軌道溝の溝径（円弧面の曲率半径）、Δｒは、ラジアルすきまとする。

Where α is the contact angle, Da is the diameter of the ball 3, ri is the groove diameter of the inner ring raceway groove (the radius of curvature of the arc surface), re is the groove diameter of the outer ring raceway groove (the radius of curvature of the arc surface), Δr is a radial clearance.

  As can be seen from the equation (1), when the groove diameter of the outer ring raceway groove 1a on the anti-load side is increased, the internal radial clearance is also increased, and the contact angle α2 on the anti-load side is increased. As a result, the load side contact angle α1 <the anti-load side contact angle α2.

Generally, α2−α1 is preferably set to 5 ° or more in order to suppress the two points of the outer ring 1.
On the other hand, the load side contact angle α1 is usually set to 20 ° to 40 ° in order to appropriately support the axial load Fa. Furthermore, in high-speed rotation applications to which the present invention is applied, the load-side contact angle α1 is preferably small because it is generally used with a light load in order to suppress a reduction in peeling life under high-speed conditions. Usually, it is set to 20 ° to 30 °.

  If the anti-load side contact angle α2 is too large, the contact point between the ball 3 and the groove reaches the groove shoulder (for example, the end on the inner ring outer diameter side), so the anti-load side contact angle α2 is 50 °. The following is preferable. That is, α2-α1 is preferably set at 5 ° to 30 °.

  Therefore, according to the four-point contact ball bearing 10 of the present embodiment, the contact angle α2 on the anti-load side is larger than the contact angle α1 on the load side, so that it was used at high speed rotation with an axial load applied. However, by preventing the outer ring raceway groove 1a and the balls 3 from hitting multiple points, early bearing damage due to slipping can be prevented, and a long life can be achieved.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
For example, in the above embodiment, the cage 4 has an outer ring guide type because it has a single outer ring 1 and an inner ring 2 composed of two divided rings divided in the axial direction. However, in the case of using the outer ring 1 composed of two divided wheels divided into two in the axial direction and the single inner ring 2, the cage 4 may be an inner ring guide system.

DESCRIPTION OF SYMBOLS 1 Outer ring 1a Outer ring raceway groove 1a1, 1a2 Circular arc surface 2 Inner ring 2a Inner ring raceway groove 3 Ball 4 Cage 10 Four-point contact ball bearing A, B Straight line C Bearing center line O Ball center αo Outer ring side rest angle αi Inner ring side rest angle α1 Load side contact angle α2 Anti-load side contact angle

Claims (3)

An outer ring having an outer ring raceway groove formed on the inner peripheral surface;
An inner ring having an inner ring raceway groove formed on the outer peripheral surface;
A plurality of balls arranged to roll freely between the outer ring raceway groove and the inner ring raceway groove;
A cage for holding the plurality of balls in a circumferential direction at a predetermined interval;
Have
In a stationary state, when the ball is pressed in the radial direction, the ball is a four-point contact ball bearing that contacts the outer ring raceway groove and the inner ring raceway groove at two points,
A four-point contact ball bearing characterized in that the outer ring side rest angle is smaller than the inner ring side rest angle. An outer ring having an outer ring raceway groove formed on the inner peripheral surface;
An inner ring having an inner ring raceway groove formed on the outer peripheral surface;
A plurality of balls arranged to roll freely between the outer ring raceway groove and the inner ring raceway groove;
A cage for holding the plurality of balls in a circumferential direction at a predetermined interval;
Have
In a stationary state, when the inner and outer rings are pressed in the thrust direction, the ball is a four-point contact ball bearing that contacts the outer ring raceway groove and the inner ring raceway groove with a contact angle,
A four-point contact ball bearing characterized in that the contact angle on the non-load side is larger than the contact angle on the load side.   The four-point contact ball bearing according to claim 2, wherein a groove diameter of the outer ring raceway groove on the non-load side is larger than a groove diameter of the outer ring raceway groove on the load side.

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