JP6561539B2 - Single row ball bearing - Google Patents

Description

  The present invention relates to a single-row ball bearing, and more particularly to a single-row ball bearing that is used in a screw compressor or the like and can receive an axial load and a radial load from both sides in an axial direction in a single row.

  Conventionally, a four-point contact ball bearing is known as a bearing that receives an axial load and a slight radial load from both sides in the axial direction in a single row. As shown in FIGS. 5 and 6, in the four-point contact ball bearing 100, generally, a plurality of balls 3 are circumferentially arranged by the cage 4 between the outer ring 1 and the two inner rings 2 divided in the axial direction. It is held so as to roll freely at a predetermined interval in the direction. On the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the inner ring 2, an outer ring raceway groove 1a and an inner ring raceway groove 2a are formed by two circular arc surfaces 1a1, 1a2, 2a1, 2a2 having different centers of curvature.

  Specifically, as shown in FIG. 6, the two arcuate surfaces 1a1 and 1a2 of the outer ring raceway groove 1a have the same curvature radii re1 and re2, and the axes of the respective curvature centers of the two arcuate surfaces 1a1 and 1a2 from the ball center O. The azimuth displacement amounts te1 and te2 are equal, and the contact angles αe1 and αe2 formed on both sides in the axial direction are designed to be equal at two points where the two arcuate surfaces 1a1, 1a2 and the ball 3 are in contact with each other (ie, re1 = re2, te1 = te2, αe1 = αe2).

Similarly, the two arc surfaces 2a1 and 2a2 of the inner ring raceway groove 2a have the same curvature radii ri1 and ri2, and the axial displacements ti1 and ti2 of the respective curvature centers of the two arc surfaces 2a1 and 2a2 from the ball center O are the same. Equally, the contact angles αi1 and αi2 formed on both sides in the axial direction are designed to be equal at two points where the two arcuate surfaces 2a1 and 2a2 and the ball 3 contact each other (ie, ri1 = ri2, ti1 = ti2, αi1 = αi2).
That is, the outer ring raceway groove 1a and the inner ring raceway groove 2a are formed symmetrically with respect to the axial center.

In the state where the four-point contact ball bearing is assembled to the mechanical device, an axial load is applied to the four-point contact ball bearing as shown in FIG. In this state, the ball 3 contacts the arc surface 1a1 of the outer ring raceway groove 1a and the arc surface 2a1 of the inner ring raceway groove 2a at one point, the contact angle between the outer ring 1 and the ball 3 is θe, and the inner ring 2 and the ball 3 The contact angle with is θi.
In FIGS. 7A to 7C, the arc shapes of the outer ring raceway groove 1a and the inner ring raceway groove 2a are represented by linear shapes for simplification.

  When rotated from the state of FIG. 7A, as shown in FIG. 7B, the ball 3 is pressed against the outer ring 1 by the centrifugal force acting on the ball 3, and the contact point with the outer ring raceway groove 1a is: The outer ring raceway groove 1a moves to the center, and the contact angle βe formed between the outer ring 1 and the ball 3 is smaller than θe (θe> βe). On the contrary, the contact point with the inner ring raceway groove 2a is the inner ring raceway groove 2a. Moving to the outside, the contact angle βi between the inner ring 2 and the ball 3 becomes larger than θi (θi <βi).

  When the rotation speed is further increased in the state of FIG. 7B or the axial load is reduced, as shown in FIG. 7C, the contact angle βe1 formed by the outer ring 1 and the ball 3 becomes smaller than βe ( βe> βe1), conversely, the contact angle βi1 formed by the inner ring 2 and the ball 3 is further larger than βi (βi <βi1). Finally, the outer ring 1 and the ball 3 are in two-point contact. The contact angle between the outer ring 1 and the ball 3 is βe1> βe2 where βe1 is the contact angle in the axial load direction and βe2 is the contact angle in the anti-axial load direction.

  Thus, the movement of the ball 3 is controlled by the contact angle that varies with the rotational speed of the shaft. When the four-point contact ball bearing receives the axial load Fa, the ball 3 is controlled by the magnitude of the spin friction in the outer ring 1 and the inner ring 2.

  That is, as shown in FIG. 7B, of the outer ring 1 and the inner ring 2, pure rolling is performed on the side of the race ring where the spin friction is large, and spin motion and rolling motion coexist on the other race ring side. Generally, when the speed is increased, the outer ring control is performed around the rotation axis O-Oe of the outer ring control. O-Oi represents the rotation axis of the inner ring control.

Further, as shown in FIG. 7 (c), at high speed rotation, the outer ring 1 is purely rolled on the arc surface side where the contact surface pressure is high and the spin friction is large, while the contact surface pressure is low and the spin friction is small. Spin motion and rolling motion coexist on the arc surface side. That is, on the side of the arc surface 1a1 where the spin friction is large, pure rolling motion is performed around the rotation axis O-Oe1 of the outer ring 1, but on the side of the arc surface 1a2 where the spin friction is small, the rotation axis O-Oe2 of the outer ring 1 is performed. Spin motion and rolling motion coexisting around
FIG. 8 shows the state of high-speed rotation in FIG. 7C as an arc-shaped outer ring raceway groove 1a and inner ring raceway groove 2a.

  Although the two-point contact itself is not a particularly abnormal phenomenon, the radial contact positions of the two arcuate surfaces 1a1, 1a2 of the outer ring raceway groove 1a, which are the respective contact points, and the ball 3 are different. The peripheral speed at the contact part is different and slipping occurs. Even if slippage occurs, it is considered that the bearing is not damaged if the lubrication between the raceway grooves and the balls is good and the oil film is sufficiently formed. However, it is conceivable that the occurrence of slip increases heat generation, causing an oil film breakage between the raceway groove and the ball, leading to bearing damage early.

  As a conventional 4-point contact ball bearing, the ball contacts the inner ring raceway surface at two points, the ball contacts the outer ring raceway surface at two points, and the inner ring raceway surface and the outer ring raceway surface are related to the bearing center. What consists of a circular arc surface which differs on both axial directions is known (for example, refer patent document 1). Specifically, in each arc surface, the radius of curvature is different from each other at the contact point with the ball, or the design is such that the contact angle between the raceway surface on both sides in the axial direction and the ball is different from each other. Even when is working, the ball always causes a spin motion to prevent poor lubrication.

JP 2002-21855 A

  However, according to Patent Document 1, it is premised on the use by contact at four points. In some cases, as in the above, the load condition in the axial direction and the lubrication state are not good. It is considered that the oil film is cut between the raceway groove and the ball, and the bearing is damaged early.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a single row ball that can achieve a long life by preventing multiple hits between the raceway groove and the ball in high-speed operation. It is to provide a 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
The outer ring raceway groove and the inner ring raceway groove have two arc surfaces with different curvature centers on both sides with respect to the center in the width direction, respectively.
In a stationary state, when the ball is pressed against the outer ring raceway groove, the ball contacts the outer ring raceway groove at two points, and when the ball is pressed against the inner ring raceway groove, the ball is A single row ball bearing that contacts the inner ring raceway groove at two points,
The outer ring or the inner ring is composed of two divided wheels divided in the axial direction,
In the outer ring raceway groove, the curvature radii of the two arc surfaces are equal to each other, and when the ball is pressed against the outer ring raceway groove at two points, the single row ball bearing passes through the center of the ball. Contact formed on both sides in the axial direction formed by respective lines connecting the points where the balls contact the outer ring raceway groove at two points and the centers of the balls with respect to a line extending in the radial direction of The single row ball bearing characterized in that the angle is an angle different from each other between 20 ° and 35 ° .
(2) The single-row ball bearing according to (1), wherein in the outer ring raceway groove, axial displacement amounts of the respective curvature centers of the two arcuate surfaces from the ball center are different from each other.

  According to the single row ball bearing of the present invention, the outer ring raceway grooves are designed such that the curvature radii of the two arc surfaces are equal to each other and the contact angles formed on both sides in the axial direction are different from each other. Even when a load and a radial load are applied and used at a high speed, by preventing multiple contact between the raceway groove and the ball, early bearing damage due to sliding can be prevented, and a long life can be achieved.

It is sectional drawing of the single row ball bearing which concerns on one Embodiment of this invention. (A) is a figure for demonstrating the design dimension of two circular arc surfaces of the outer ring raceway groove | channel of FIG. 1, (b) is a figure for demonstrating the design dimension of two circular arc surfaces of an inner ring raceway groove | channel. It is. It is sectional drawing which simplified the raceway groove | channel which shows the state which assembled the single row ball bearing of FIG. (A)-(c) is a figure for demonstrating the contact state of a raceway groove | channel and a ball | bowl in the state where the axial load acted on the single row ball bearing of FIG. It is sectional drawing of the conventional 4-point contact ball bearing. (A) is a figure for demonstrating the design dimension of two circular arc surfaces of the outer ring raceway groove | channel of FIG. 5, (b) demonstrates the design dimension of two circular arc surfaces of the inner ring | wheel raceway groove | channel of FIG. FIG. (A)-(c) is a figure for demonstrating the contact state of a raceway groove | channel and a ball in the state in which the axial load acted on the conventional ball bearing. It is a figure for demonstrating the state of FIG.7 (c) using sectional drawing of the 4-point contact ball bearing of FIG.

  Hereinafter, one embodiment of a single row ball bearing concerning the present invention is described in detail based on a drawing. In addition, the same code | symbol is attached | subjected about the same or equivalent part as the conventional rolling bearing shown in FIG. 5, and description is abbreviate | omitted or simplified.

  As shown in FIG. 1, a single row ball bearing 10 of the present 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, respectively. A plurality of balls 3, which are arranged between the outer ring 1 and the inner ring 2 so as to roll freely at a predetermined interval, and a plurality of balls 3. And an outer ring guide type retainer 4 that is retained 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.

  The material of the cage 4 may be brass, a synthetic resin material to which glass fiber or carbon fiber is added. For example, the synthetic resin cage may be manufactured by injection molding.

  Here, in the present embodiment, the inner ring raceway groove 2a is formed symmetrically with respect to the axial center as in the case of the conventional inner ring raceway groove, while the outer ring raceway groove 1a is left and right with respect to the axial center. It is formed asymmetrically.

  Specifically, as shown in FIG. 2, the two arc surfaces 1a1, 1a2 of the outer ring raceway groove 1a have the same radius of curvature re1, re2, while the center of curvature of each of the two arc surfaces 1a1, 1a2 from the ball center O. When the ball 3 is pressed in the radial direction toward the outer ring raceway groove 1a in the stationary state, the two arcuate surfaces 1a1, 1a2 and the ball 3 are in contact with each other in the axial direction displacement amount te1, te2, respectively. The contact angles αe1 and αe2 formed on both sides in the axial direction are designed to be different (that is, re1 = re2, te1 ≠ te2, αe1 ≠ αe2).

  The two arc surfaces 2a1 and 2a2 of the inner ring raceway groove 2a have the same radius of curvature ri1 and ri2, the axial displacements ti1 and ti2 of the respective centers of curvature of the two arc surfaces 2a1 and 2a2 from the ball center O are equal, and In a stationary state, when the ball 3 is pressed in the radial direction toward the inner ring raceway groove 2a, the contact angles αi1 formed on both sides in the axial direction at two points where the two arcuate surfaces 2a1, 2a2 and the ball 3 come into contact with each other. , Αi2 are designed to be equal (ie, ri1 = ri2, ti1 = ti2, αi1 = αi2).

In this embodiment, the curvature radii re1 and re2 of the two arcuate surfaces 1a1 and 1a2 of the outer ring raceway groove 1a are:
re1 = re2 and 0.52Dw ≦ re1, re2 ≦ 0.56Dw
Set to
The contact angles αe1 and αe2 between the two arcuate surfaces 1a1 and 1a2 of the outer ring raceway groove 1a and the ball 3 are:
αe1 ≠ αe2 and 20 ° ≦ αe1, αe2 ≦ 35 °
Set to
Further, axial displacements te1 and te2 of the respective curvature centers of the two arcuate surfaces 1a1 and 1a2 of the outer ring raceway groove 1a from the ball center O are as follows:
te1 ≠ te2 and 0.006Dw ≦ te1, te2 ≦ 0.04Dw
Set to

  Here, with reference to FIG.3 and FIG.4, the contact state of a raceway groove | channel and a ball in the state which the axial load acted on the single row ball bearing 10 of this embodiment is demonstrated. 3 and 4, the arc shapes of the outer ring raceway groove 1 a and the inner ring raceway groove 2 a are represented by linear shapes for simplification. Here, the radius of curvature of each arc surface is set to re1 = re2 = ri1 = ri2, the amount of axial displacement of the center of curvature of each arc surface is set to te2 <te1 = ti1 = ti2, and each contact angle is set to αe2 <αe1. = Αi1 = αi2.

  As shown in FIG. 3, in a state where the single row ball bearing is assembled, if the radial clearances between the arc surface 1a1 and the arc surface 1a2 of the outer ring raceway groove 1a and the ball 3 are Δre1 and Δre2, respectively, Δre2> Δre1 Become. For this reason, in a state where the ball 3 is pressed against the outer ring raceway groove 1a in the radial direction, the outer ring 1 comes into contact with the ball 3 on the side having a small radial clearance (Δre1) and does not hit two points.

  As shown in FIG. 4 (a), when an axial load Fa is applied to the single row ball bearing 10, the ball 3 is 1 each of the arc surface 1a1 of the outer ring raceway groove 1a and the arc surface 2a1 of the inner ring raceway groove 2a. Contact is made at a point, and the contact angle between the outer ring 1 and the ball 3 is θe, and the contact angle between the inner ring 2 and the ball 3 is θi. At this time, a clearance of Δθ is provided between the circular arc surface 1a2 of the outer ring raceway groove 1a and the ball 3.

When rotated from the state of FIG. 4A, as shown in FIG. 4B, the ball 3 is pressed against the outer ring 1 by the centrifugal force acting on the ball 3, and the contact point with the outer ring raceway groove 1a is: It moves to the center of the circular arc surface 1a1, and the contact angle βe formed by the outer ring 1 and the ball 3 is smaller than θe (θe> βe). Further, the arc surface 1a2 of the outer ring raceway groove 1a and the ball 3 are not in contact with each other, but the clearance Δβ between the arc surface 1a2 of the outer ring raceway groove 1a and the ball 3 is reduced as the contact angle βe is reduced. (Δθ> Δβ).
The contact point with the inner ring raceway groove 2a moves to the outside of the circular arc surface 2a1, and the contact angle βi between the inner ring 2 and the ball 3 becomes larger than θi (θi <βi).
Thus, the movement of the ball 3 is controlled by the contact angle that changes with the rotational speed of the shaft.

When the rotating speed is further increased in the state of FIG. 4B or the axial load Fa is reduced, the contact angle βe1 formed by the outer ring 1 and the ball 3 becomes smaller than βe as shown in FIG. 4C. (Βe> βe1), the clearance Δβ1 between the circular arc surface 1a2 of the outer ring raceway groove 1a and the ball 3 is further reduced (Δβ> Δβ1).
However, since the axial displacement amount of each curvature center is te2 <te1 = ti1 = ti2 and each contact angle is αe2 <αe1 = αi1 = αi2, the outer ring 1 and the ball 3 do not reach two points. The contact angle βi1 formed by the inner ring 2 and the ball 3 is further larger than βi (βi <βi1).

  By designing the outer ring raceway groove 1a and the inner ring raceway groove 2a in this way, it is possible to avoid contact between the outer ring 1 and the ball 3 even at high speed rotation, and prevent early bearing damage due to slipping. Lifespan can be achieved.

  Hereinafter, the present invention will be described with reference to the following test conditions and internal specifications, taking as an example the single-row ball bearing shown in FIG. 1 having an inner ring inner diameter of 35 mm, an outer ring outer diameter of 62 mm, and a width of 17 mm, and the four-point contact ball bearing shown in FIG. The effect of was confirmed. That is, in the embodiment of the present invention, in a stationary state, the contact angle αe1 between the outer ring 1 and the ball 3 in the axial load direction is larger than the contact angle αe2 between the outer ring 1 and the ball 3 in the anti-axial load direction (αe1> αe2).

* Test conditions Rotation speed: 22300min ^-1
Axial load 130kgf

* Internal specifications of the 4-point contact ball bearing in Fig. 5 (Dw: ball diameter)
ri1 = ri2 = re1 = re2 = 0.52Dw
αi1 = αi2 = 31.5 °, αe1 = αe2 = 31.5 °
ti1 = ti2 = 0.01Dw, te1 = te2 = 0.01Dw

* Internal specifications of the ball bearing in FIG. 1 ri1 = ri2 = re1 = re2 = 0.52Dw (Dw: ball diameter)
αi1 = αi2 = 31.5 °, αe1 = 31.5, αe2 = 20 °
ti1 = ti2 = 0.01Dw, te1 = 0.01Dw, te2 = 0.007Dw

  As a result of the analysis using the above-described ball bearing, in the ball bearing shown in FIG. 5, the outer ring 1 showed two points, but in the ball bearing shown in FIG. There wasn't.

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.

  In the present embodiment, the outer ring raceway groove 1a has an asymmetrical shape. However, in the present invention, at least the outer ring raceway groove may be an asymmetrical shape, and the inner ring raceway groove also has an asymmetrical shape, that is, a radius of curvature of two arcuate surfaces. May be equal to each other and contact angles formed on both sides in the axial direction may be different from each other.

DESCRIPTION OF SYMBOLS 10 Ball bearing 1 Outer ring 1a Outer ring raceway groove 1a1, 1a2 Arc surface 2 Inner ring 2a Inner ring raceway groove 2a1, 2a2 Arc surface 3 Ball 4 Cage

Claims (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
The outer ring raceway groove and the inner ring raceway groove have two arc surfaces with different curvature centers on both sides with respect to the center in the width direction, respectively.
In a stationary state, when the ball is pressed against the outer ring raceway groove, the ball contacts the outer ring raceway groove at two points, and when the ball is pressed against the inner ring raceway groove, the ball is A single row ball bearing that contacts the inner ring raceway groove at two points,
The outer ring or the inner ring is composed of two divided wheels divided in the axial direction,
In the outer ring raceway groove, the curvature radii of the two arc surfaces are equal to each other, and when the ball is pressed against the outer ring raceway groove at two points, the single row ball bearing passes through the center of the ball. Contact formed on both sides in the axial direction formed by respective lines connecting the points where the balls contact the outer ring raceway groove at two points and the centers of the balls with respect to a line extending in the radial direction of The single row ball bearing characterized in that the angle is an angle different from each other between 20 ° and 35 ° .   2. The single row ball bearing according to claim 1, wherein in the outer ring raceway groove, axial displacement amounts of the respective curvature centers of the two arcuate surfaces differ from each other from the center of the ball.

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