JP2508181B2 - Ball bearing cage - Google Patents

Description

The present invention relates to a ball guide type cage of a ball bearing used in a large motor or the like, and more particularly, to improve cage shape and squeak noise by improving the pocket shape. This suppresses the generation of abnormal noise.

[Problems to be Solved by Conventional Techniques and Inventions]

For example, for ball bearings for large motors that cannot be mass-produced,
A machined cage is used. Usually, in this type of cage, there are two types of guides for the cage when the bearing is rotating, that is, an outer ring or inner ring guide ring type and a ball guide type. As shown in FIG. 5, the normal ball guide type cage is a cage 4 for retaining balls 3 arranged between an outer ring 1 and an inner ring 2.
Pocket surface 4a of the ball 3 has the same shape as the curved surface (spherical surface) of the ball 3 and has a radius R _{1 and} the center of curvature O ₁ is on the pitch circle PC of the ball 3 and the [pitch circle and cage outer diameter range] The dimension] T ₁ and the dimension between the pitch circle and the cage inner diameter T ₂ are equal to each other.

The cage 4 configured in this manner has a large radial movement amount Δr, and rotates while vibrating greatly in the radial direction as the bearing rotates (whirl). Therefore balls 3 and cage 4
There is a problem that a so-called cage sound is likely to be generated due to the collision with.

Since the bearing for an electric motor is particularly required to have low noise, it is necessary to reduce the above-mentioned cage noise. As a countermeasure, it is conceivable to reduce the radius of curvature R ₁ of the pocket surface 4a to reduce the clearance with the ball 3 to reduce the radial movement amount Δr of the cage 4, but in that case, it is inevitable. In addition, the clearance between the cage and the balls 3 in the circumferential direction also becomes small.

Normally, in a ball bearing having a ball guide type retainer, when a radial load is applied to the bearing, the retainer 4 has the entire circumference of the pocket surface 4a as shown by the hatched portion A in FIG. It is supported by contacting the upper surface of the ball 3 in an annular shape. Therefore, if the radius of curvature R ₁ of the pocket surface 4a is reduced to close the gap with the ball 3, not only the radial movement of the cage 4 but also the smooth rolling movement of the ball 3 in the circumferential direction is restricted. Will end up. If the movement of the balls 3 in the circumferential direction of the cage 4 is excessively restricted in this way, the cage 4 will be overloaded, and in the worst case, the cage will be damaged. The reason is that, when a radial load and an axial load are applied to the radial ball bearing, the load distribution of each ball 3 in the load zone differs due to the difference in the position of each ball with respect to the load direction. The contact angle changes according to the load distribution. Then, the revolution speed of each ball 3 differs from the revolution speed of the cage 4 according to the change in the contact angle, and the balls 3 interfere with the cage 4.

Also, if the circumferential clearance of the cage becomes smaller, the balls 3
Since it is difficult for grease to enter the gap between the pocket surface 4a and the pocket surface 4a, there is a problem that abnormal noise is likely to occur due to poor lubrication.

As a means for preventing the above-mentioned cage from being damaged, conventionally, for example, the pocket shape of a press cage made of steel plate has a long hole shape, and the major axis of the pocket is arranged in the circumferential direction of the cage, thereby There has been proposed a device (described in Japanese Utility Model Publication No. 54-36991) in which interference with the cage is prevented.

However, in that case, the radial pocket gap is not changed from that of the conventional one, and only the circumferential pocket gap is set to a predetermined size (a size equal to or larger than the advance / delay amount of the ball based on the revolution speed difference between the ball and the cage). ), The circumferential clearance is too large. As a result, when the ball moves from the unloaded zone to the loaded zone, the ball moves freely in the circumferential direction and collides with the cage vigorously, resulting in an increase in cage noise.

The present invention has been made in view of such conventional problems. The thickness of the cage is unequal above and below the pitch circle of the ball, and the pocket shape is long in the circumferential direction. By shortening the direction, the amount of movement of the cage and the ball in the radial direction is regulated, and the cage in which the movement of the ball in the circumferential direction is appropriately free is provided, and the above-mentioned conventional problems are solved. The purpose is to do.

[Means for Solving the Problems] The present invention to achieve the above object, in a ring-shaped ball guide type cage for holding and guiding balls of a ball bearing, at least a part of a pocket surface of the cage, The curved surface of the ball is approximately the same as the curved surface of the ball, the center of curvature of the curved surface is placed on the pitch circle of the ball, and the dimension between the pitch circle and the cage outer diameter is different from the dimension between the pitch circle and the cage inner diameter. , And the pocket cross-sectional shape in the direction along the circumference of the cage is long in the circumferential direction,
The spindle shape is short in the axial direction.

[Action]

When the bearing is used on a horizontal rotary shaft, the retainer lowers by its own weight in a direction parallel to a line connecting the center of the retainer pocket and the center of the retainer (hereinafter, referred to as a gravity direction). In the present invention, when the thickness T of the cage is T = T ₁ + T ₂ ,
Since the dimension between the cage outer diameter] T ₁ and the dimension between the pitch circle and the cage inner diameter T ₂ are not equal to each other, the movement of the cage in the gravitational direction is greater than that in the conventional case of T ₁ = T _2. The quantity Δr ₁ becomes smaller. For example, if T ₁ > T ₂ , then the cage will only drop a small amount,
At the center of the upper unloaded zone, a point on the ridgeline on the outer diameter side of the pocket moves in the direction of gravity and contacts the ball surface. vice versa
If T ₁ <T ₂ , the point on the ridgeline on the inner diameter side of the pocket moves in the direction of gravity and contacts the ball surface at the center of the load zone below the cage.

That is, the radial amplitude of the cage becomes extremely small and the cage noise is reduced. In addition, radial play of the balls is suppressed by the cage. This reduces the squeaking noise.

The contact surface between the ball surface and the outer diameter side or the inner diameter side of the pocket is not annular as in the conventional case. That is, the contact between the balls and the cage is performed along the pocket ridgeline represented by the arcs facing each other in the axial direction, and a moderate space is kept tapering in the circumferential direction. Therefore, it is also possible to prevent the conventional phenomenon that the balls move too much in the circumferential direction and collide with the cage vigorously to generate cage noise.

Further, the circumferential pocket space also has a grease retaining function, sufficient lubrication is ensured during movement of the balls and the cage, and the occurrence of abnormal noise such as squeaking noise is effectively reduced.

〔Example〕

An embodiment of a ball guide type cage according to the present invention will be described below with reference to the drawings.

1 to 4 show one embodiment of the present invention. The same or corresponding parts as in the conventional case are designated by the same reference numerals.

Reference numeral 10 denotes a split type machined cage that guides the balls 3 of the ball bearing, and has a large number of pockets provided at equal intervals in the circumferential direction.
Balls 3 made of steel balls each having a radius R are inserted into the inside 11, two symmetrically formed rings are joined at a dividing surface B, and they are fastened together by a rivet 5.

Pocket surface in each pocket 11 of the cage 10 having the wall thickness T
The shape of 11a is formed as follows. That is, the vertical cross-sectional shape of the pocket 11 is such that the ball 3 having a radius R is at least near the center as shown in FIGS.
And a radius of curvature R ₁ = ball radius R +
The gap is C ₁ . The center of curvature O ₁ is on the ball pitch circle PC.
Regarding the thickness T of the cage 10, the thickness T ₁ on the outer diameter side and the thickness T ₂ on the inner diameter side of the pitch circle PC are different, and in this embodiment, T ₁ > T _2. .

By forming in this way, the cage shown in FIG.
The amount of movement Δr _{1 in the} direction of gravity of 10 is smaller than the amount of movement Δr in the direction of gravity in the conventional cage indicated by the chain line in FIG.

Also, the sharp ridgeline on the inner diameter side of the pocket 11 is cut off,
A gentle corner portion 11b is formed.

The applicant of the present invention has previously proposed another means for suppressing the amount of movement of the cage in the direction of gravitational force (Shokaisho 58-195118).
This is different from that of the present invention in that the center of curvature of the pocket surface in the radial direction of the cage is unevenly distributed by a predetermined amount δ with respect to the pitch circle of the ball.

As for the circumferential direction, the above-mentioned radial pocket surface 11
The radius of curvature R ₂ is larger than the radius of curvature R _{1 of a} , and the center of curvature O ₂ has a dimension t in the radial direction with respect to the center of curvature O ₁ .
Only shifted. The size of the radius of curvature R ₂ is appropriately determined in consideration of the contradictory conditions such as the suppression of the play amount of the ball 3 in the radial direction and the freedom of movement in the circumferential direction.

Thus, the pocket cross-sectional shape in the direction along the circumference of the cage 10 is synthesized by symmetrically abutting two arcs of the same diameter that curve in opposite directions, and is generally long in the circumferential direction and short in the axial direction. It has a spindle shape.

 Next, the operation will be described.

When the bearing having the retainer 10 thus formed is attached to the rotary shaft of the horizontal rotary machine, the retainer 10 is slightly lowered by its weight. When the amount of movement Δr _{1 in the} direction of gravity from the ridgeline on the outer diameter side of the cage pocket surface 11a to the surface of the ball 3 becomes zero in the upper no-load zone, the cage 10 causes the ball 3 to move.
Abutting against, it can no longer be lowered. The cage movement amount Δr ₁ in this embodiment is extremely small. Therefore,
Although the retainer 10 revolves with the rotation of the shaft, the vertical vibration is suppressed, and the retainer noise is effectively reduced.

Further, in the load zone on the lower side of the cage, the cage pocket surface 11a and the balls 3 do not come into contact with each other and a gap is maintained. Therefore, the weight of the retainer 10 is applied to the balls 3 in the upper unloaded area and becomes an opposing force against the centrifugal force acting on the rotating balls 3. As a result, the contact pressure between the ball 3 and the outer ring 1 of the bearing in the unloaded area is reduced, and the illegal movement of the ball 3 is restricted by the contact of the cage 10.
The generation of squeak noise can also be prevented.

The contact point between the cage 10 and the ball 3 is a crescent-shaped hatched portion A ₁ shown in FIG. 2 unlike the conventional annular shape. That is, the contact is performed along the pocket ridgeline represented by the arcs facing each other in the axial direction, and in the circumferential direction, a proper space is tapered toward the dividing surface B. An opening 13 is formed at the end of the pocket 11 in the circumferential direction between the pocket 11 and the ball 3.

Therefore, the ball 3 and the cage 10 do not interfere in the circumferential direction. Like conventional slotted pockets, the gap is too large and the balls move too much in the circumferential direction, colliding with the cage vigorously and producing a so-called ball drop sound (a kind of cage sound). Is also prevented.

Further, since the pocket gap at the end portion in the circumferential direction is large, a large amount of grease is retained therein. This grease easily enters the pocket gap from the gentle corner portion 11b on the inner diameter side of the pocket 11 and smoothly circulates through the opening 13 at the pocket end in the circumferential direction, and the grease between the ball 3 and the cage 10 is Provide sufficient lubrication. This also effectively reduces the generation of squeaking noises and the like.

In the above embodiment, the relationship between the thickness T ₁ on the outer diameter side of the pitch circle PC and the thickness T ₂ on the inner diameter side is T ₁ > T ₂ , but the invention is not limited to this. It may be T ₁ <T ₂ .

〔The invention's effect〕

As described above, according to the present invention, the pocket surface of the cage is spherical in the axial direction and its center of curvature is placed on the pitch circle of the ball, and the cage thickness is changed by the inner diameter of the pitch circle. Furthermore, the cage is formed into a substantially spindle shape that is long in the circumferential direction and short in the axial direction. Therefore, the following effects were obtained.

The vibration of the cage in the radial direction can be suppressed, and the movement of the balls in the circumferential direction can be appropriately adjusted. As a result, the cage noise is greatly reduced.

The radial play of the ball in the no-load zone can be suppressed, sufficient lubrication is possible, and the generation of squeaking noise is almost suppressed.

Low noise has been realized, and the bearing life has been extended based on the conventional acoustic failure.

[Brief description of drawings]

FIGS. 1 to 4 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part of a bearing, FIG. 2 is a partial side view of the outer shape of a cage, and FIG. Fig. 4 is a partially enlarged view, and Fig. 4 is the third.
Fig. 5 is a sectional view taken along the line IV-IV in Fig. 5, Fig. 5 is a longitudinal sectional view of a bearing main part having a conventional cage, and Fig. 6 is a partial side view of the outer shape of the conventional cage. In the figure, 3 is a ball, 10 is a cage, 11 is a pocket, 11
a is the pocket surface, O ₁ is the center of curvature, PC is the pitch circle, T ₁ is the pitch circle to cage outer diameter dimension, and T ₂ is the pitch circle to cage inner diameter dimension.

Claims (1)

(57) [Claims] 1. A ring-shaped ball guide type cage for holding and guiding balls of a ball bearing, wherein at least a part of a pocket surface of the cage is a curved surface having substantially the same shape as the curved surface of the ball.
The center of curvature of the curved surface is set on the pitch circle of the ball, the dimension between the pitch circle and the cage outer diameter is made different from the dimension between the pitch circle and the cage inner diameter, and a pocket along the circumference of the cage. A cage for ball bearings having a substantially spindle-shaped cross-sectional shape that is long in the circumferential direction and short in the axial direction.