JP2002333028A - Crowned holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably maintain the high lubricating performance of a ball bearing for a long period in spite of a less amount of grease by returning the grease scraped off by pockets to a raceway groove in the ball bearing. SOLUTION: Cutout portions 13 are provided between the pockets 12 of a crowned holder 11 where they are open to the other side face 17 of the holder in opposition to the opening sides of the pockets and overlapped with the bearing raceway groove 21, while one side face 11 of the holder with the open pockets is formed as a plane extending to the inside of the bearing raceway groove. The cutout portions 13 function as return passages for the grease during operation of the ball bearing to permit the return of the grease scraped off the surfaces of balls 20 of the ball bearing by the pockets 12 to the raceway groove 21 in the ball bearing with centrifugal force following the rotation of the crowned holder 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball bearing which is incorporated in a ball bearing in which grease is sealed, and which is rollably held in a bearing raceway groove from above and below along the raceway groove. The present invention relates to a crown type retainer in which semicircular pockets are opened at predetermined intervals on one side surface for holding at equal intervals, and more particularly, to each of the crown type retainers from the surface of a ball of a ball bearing. The present invention relates to a structure of a crown type cage for returning grease scraped by a pocket to a raceway groove of a ball bearing.

[0002]

2. Description of the Related Art In general, ball bearings are widely used as rolling bearings for supporting various rotating parts such as bearings of various rotating machines. The ball bearing is used by fitting a shield plate made of metal, rubber, resin, or the like to both side surfaces or one side surface in order to prevent leakage and scattering of grease sealed therein.

As a cage incorporated in such a ball bearing, a crown type cage as shown in FIGS. 4 and 5 is known. Conventionally, as the crown-shaped retainer 40, there is known a crown-shaped retainer 40 having a plurality of substantially semicircular pockets 42 provided with openings on one side surface at predetermined intervals in a circumferential direction of a retainer base 41 formed in an annular shape. Have been.

In general, a ball bearing provided with a retainer of the above-described type guides a ball (ball) from an up-down direction in an orbital groove having an arc-shaped cross section by an inner ring and an outer ring, respectively. In order to keep the circumferential interval of each ball constant at all times, and to facilitate the insertion of the balls into the raceways of the inner and outer races during the assembly of the bearing, the crown shape is set between the upper and lower raceways from the lateral direction. The configuration in which the ball is held by the holder 40 is adopted. In this type of cage, the claw 4
3 are provided to project laterally so as to define the open end of each pocket 42. The inner peripheral surface of each claw portion 43 is formed as a spherical surface that is continuous with the inner peripheral surface of each corresponding pocket 42.

In the above-described conventional crown type cage 40, the edge of each pocket 42 of the cage base 41 scrapes off the grease adhering to the surface of each ball during operation of the assembled ball bearing. The scraped grease 44 moves radially outward from the pocket on the inner or outer diameter surface of the retainer base 41 as indicated by the arrow in FIG. The grease 44 thus moved is applied to both sides of the cage 40 by centrifugal force due to rotation of the cage itself, or by relative rotation between the inner and outer rings 51 and 52 of the ball bearing 50 and the crown type cage 40. By shearing, inner and outer rings 51, 5
It is scattered outside the second track groove 53 and is carried away. The grease 44 that has leaked or been removed from the bearing loses an opportunity to be returned to the raceway groove 53 of the ball bearing 50 again.

As a result, the amount of grease contributing to the lubrication of the ball bearing 50 decreases in direct proportion to the operation time of the ball bearing, and the inner peripheral surface of the pocket 42 of the crown type cage 40 and the ball 5 of the ball bearing 50 are reduced.
4 deteriorates the lubrication state. Then, with the deterioration of the lubrication state between them, a large frictional force is generated, particularly at the claw portion 43, and the crown-shaped retainer 40 generates self-excited vibration, which easily causes abnormal noise. Eventually, abnormal wear and seizure of the ball 54 of the ball bearing 50 and the raceway groove 53 of the inner and outer rings 51 and 52 due to the lack of lubrication by the grease 44 occur, which hinders the operation of the rotary machine. There was a problem.

[0007]

In recent years, ball bearings used for spindle motors of hard disk drives for computers, ball bearings used for swing arms, ball bearings used for various rotary machines in a clean room, and rotary machines for manufacturing foods and pharmaceuticals have been developed. In order to satisfy requirements such as low torque and low dust generation, the amount of grease sealed inside is reduced.

For this reason, the above-mentioned conventional crown type retainer 40
In such a case, abnormal wear and seizure of the balls 54 of the ball bearing 50 and the raceway grooves 53 of the inner and outer rings 51 and 52 due to the lack of lubrication by the grease 44 are more likely to occur due to the reduced amount of grease. Had become.

The claw portions 43 of the pockets 42 of the retainer base 41 are respectively connected to the ball bearings 50 during operation of the ball bearings 50.
Is brought into a state of being caught in the rotation direction of the balls 54 due to the sliding contact with the balls 54. For this reason, a force along the rotation direction of the ball 54 acts on each claw 43, and the claw 4
No. 3 has a problem that self-excited vibration is generated and cage sound is generated. This problem is more likely to occur as the amount of grease is reduced.

According to the present invention, the grease scraped off by each pocket can be returned to the raceway of the ball bearing, so that even if the amount of grease is small, the high lubrication performance of the ball bearing is stably secured for a long time. It is an object of the present invention to provide a crown-shaped retainer that can be used.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is to provide a notch between the adjacent pockets, the notch being open on the other side opposite to the side where the pocket opens. Is achieved by forming the one side surface, which is positioned so as to at least partially overlap the bearing raceway groove and at the same time the pocket is open, to extend along the inside of the raceway groove.

[0012]

According to this structure, when the ball bearing is operated,
The grease scraped off from the surface of the ball by the peripheral edge of the pocket and moved along the inner peripheral surface or the outer peripheral surface of the retainer while accumulating is formed on one side by centrifugal force or the like accompanying rotation of the retainer. Is stored directly in the notch on the other side without passing through the notch. The notch is positioned so as to at least partially overlap the raceway groove, and one side surface is formed as a plane extending along the inside of the raceway groove, whereby centrifugal force generated by rotation of the retainer is reduced. Then, the grease flowing into the notch is returned into the raceway groove again. At this time, at the same time, since the claw portion does not exist at the pocket opening end, the problem that self-excited vibration is generated and a retainer sound is generated is also solved.

In one embodiment of the crown type cage according to the present invention, the notch has a substantially trapezoidal shape, and both side surfaces thereof are in contact with a tangential surface of a semicircular pocket adjacent to each other. It is preferable that the trajectory is formed of a linear plane inclined in parallel and facing each other, and the short side surface thereof is positioned in the track. In such a configuration, since this type of retainer is generally manufactured by injection molding using a material in which glass fiber or the like is blended with resin, it is not necessary to form a cutout portion with a linear flat concave portion by designing a molding die. And the manufacturing is easy, and at the same time, the molding operation is easy.

In another embodiment of the crown type cage according to the present invention, the notch has a substantially trapezoidal shape in a plane, and both side surfaces are concentric with the semicircular pockets adjacent to each other. And the short side thereof is preferably positioned in the raceway groove.
With this configuration, although the mold production takes some time, the periphery of the pocket is surrounded by the inner and outer peripheral surfaces of the same width, so that the grease scraped out of the pocket is evenly distributed over the entire circumference of the pocket. It can be fed into the notch and returned stably into the bearing raceway groove.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a schematic perspective view showing a crown type cage according to a first embodiment of the present invention, and FIG. 2 is a side view of a main part of the crown type cage of FIG. FIG. 3 is a main part side view showing a crown type cage according to a second embodiment of the present invention.

In FIG. 1 and FIG. 2, a crown-shaped retainer 11 formed in an annular shape has a plurality of pockets 12 and notches 13, and is formed by injection molding using a resin containing glass fiber or the like as a material. Ball bearings (not shown) that are integrally molded and grease is applied to the raceway surfaces of the inner ring and the outer ring
Incorporated in The plurality of semicircular pockets 12 are respectively opened at predetermined intervals in the circumferential direction on one side surface 15 of the retainer 11, and the inner peripheral surface of each pocket 12 is formed of a corresponding one of the balls 20 of the ball bearing. It is formed into a spherical shape having a radius of curvature slightly larger than the radius of curvature. The crown type cage 11 holds the ball 20
Each ball is held in the pocket 12 from the lateral direction within the circumferential gap between the raceway surfaces of the inner ring and the outer ring contacting the upper and lower portions of the pocket.

The notch 13 is cut into a substantially trapezoidal shape between the pockets 12 so as to open on the other side 17 located opposite to the side 15 on which the pocket 12 opens. As shown in FIG. 2, the notch 13 has a straight plane that is inclined on both sides in parallel with the tangential planes T ₁ and T _{2 of} the semicircular pocket 12 adjacent to each other and facing each other. And the short side surface 16 is positioned so as to bite into the track 21 greatly. When the ball bearing is operated, the notch 13 removes grease (not shown) scraped from the surface of each ball 20 by the peripheral edge of each pocket 12 by centrifugal force accompanying rotation of the crown type retainer 11. It functions as a grease return flow path for returning to the raceway grooves 21 of the inner and outer rings of the ball bearing.

One side surface 15 of the retainer 11 is located on the same plane (indicated by a two-dot chain line A in FIG. 2) except for the opening of the opening of the pocket 12. That is, FIG.
As shown in a conventional crown type retainer 40 shown in FIG.
The claw portions 43 do not protrude from the open end portions on both sides of each pocket 42. Therefore, generation of cage noise due to self-excited vibration caused by stress in the direction in which the claw portion is caught in the ball during operation of the bearing is also avoided.

As shown by a two-dot chain line A in FIG. 2, one side surface 15 of the pocket of the cage 11 is a view of the raceway grooves 21 of the inner ring and the outer ring when the ball bearing is assembled. 2 and extends in the circumferential direction at a position closer to the center than the boundary line indicated by the two-dot chain line B.
Positioning the one side surface 15 flat and in the raceway groove in this way produces the same function as the above-described notch 13 as a grease return flow path.

Hereinafter, the operation of the crown type cage having the above-described configuration according to the present invention will be described. When operating ball bearings,
The ball 20 rotates in the pocket 12 so that the cage 11
Of each ball 12 of the ball bearing is
Grease adhering to the surface of No. 0 is scraped off. The scraped-off grease flows into these notches 13 along these surfaces while accumulating on the inner peripheral surface or the outer peripheral surface of the cage 11.
The grease that has flowed into each notch 13 has the notch 13 as a return flow path, and the centrifugal force and the shearing force accompanying the rotation of the crown type retainer 11 cause the raceway grooves 21 of the inner and outer races of the ball bearing.
And contributes to the lubrication of the ball bearing again.

Apart from this flow path, the pocket 1 of the cage 10
The grease deposited on the inner circumferential surface or the outer circumferential surface in the portion near the one side surface 15 where the opening 2 is opened, a part of the grease flows into the notch 13 due to the centrifugal force generated by the rotation of the retainer 10, and the remaining portion Is returned directly into the raceway groove 21 along one side surface 15 of the retainer 10. The grease deposited on any part is returned to the raceway groove. As mentioned above,
Since this type of cage is generally manufactured by injection molding using a material in which glass fiber or the like is blended with resin, the crown type cage 11 having the above-described configuration is formed by a recess formed by a linear plane. Since the notch 13 is formed, the design and manufacture of the molding die are easy, and at the same time, the molding operation is also easy.

Each of the notches 32 of the crown-shaped retainer 31 shown in FIG. 3 has an arc-shaped curved surface concentric with the semicircular pocket 12 adjacent to each other on both sides 33 and a short side surface thereof. 16 are located in the raceway groove 21. And
One side surface 15 of the retainer 31 extends in the circumferential direction inside the raceway groove 21 as in the above-described embodiment.
Therefore, these notches 32 and one side 15
The function of the grease as the return flow path is also
This is exactly the same as the embodiment.

By replacing both side surfaces of the cutout portion 32 with two opposing arcuate curved surfaces, the mold manufacturing takes some time, but the periphery of the pocket 12 is formed by the inner and outer peripheral surfaces having the same width. Since the grease is surrounded, the grease scraped out of the pocket can be evenly fed into the notch 32 over the entire circumference of the pocket, and as a result, the grease can be stably returned into the bearing raceway groove.

Further, unlike the conventional crown-type cage 40 shown in FIG. 4, the claw portions 43 do not protrude from the pockets 42 of the cage base 41. Therefore, for example, the claw portion 43 is
It is not possible for the ball 54 to get caught in the rotation direction of the ball 54 due to the sliding contact with each ball 54, and the self-excited vibration of the claw 43 does not occur. Thus, it is possible to reliably prevent the retainer sound from being generated due to the self-excited vibration of the claw portion 43.

In each of the above embodiments, the cage 1
The size and shape of each of the notches 13 and 32, the dimensional ratio of each side, the angle, the chamfered shape of the corners, and the like depend on the required performance of the ball bearings in which the crowned retainers 11 and 30 are incorporated. It should just be set suitably and it is not limited at all. Further, focusing on the effect that the ball bearing using the crown type cage according to the present invention can stably secure high lubrication performance even for a small amount of grease over a long period of time, a computer hard disk Drive spindle motor,
It is possible to suitably incorporate the ball bearing into a ball bearing used for a swing arm, or various rotary machines in a clean room, or a rotary machine that manufactures food or medicine.

[0026]

As described above, the crown type retainer according to the present invention is provided with a notch between the adjacent pockets, the cutout being opened on the other side opposite to the side where the pocket is opened. The notch portion is positioned so as to at least partially overlap the bearing raceway groove, and at the same time, the one side surface on which the pocket opens is a flat surface extending along the inside of the raceway groove. The grease scraped off by the peripheral portion of the ball bearing can be returned to the raceway groove of the ball bearing through each cutout portion or directly.
As a result, even if the amount of grease is small, the lubricating performance of the ball bearing can be stably secured over a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a crown type cage according to a first embodiment of the present invention.

FIG. 2 is a side view of a main part of the crown type cage of FIG.

FIG. 3 is a main part side view showing a crown type cage according to a second embodiment of the present invention.

FIG. 4 is a schematic perspective view showing a conventional crown type cage.

5 is a perspective view of a main part showing a flow of grease scraped off by a pocket in the crown-type cage of FIG. 4;

FIG. 6 is a sectional view showing a ball bearing incorporating the crown type retainer of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Crown type retainer 12 Pocket 13 Notch part 15 One side 17 The other side 20 Ball 21 Bearing raceway groove

Claims (1)

[Claims] 1. A ball bearing which is incorporated in a ball bearing in which grease is sealed and which is rollably held in a bearing raceway groove from above and below at equal intervals from the side along the raceway groove. A semicircular pocket having an opening at a predetermined interval on one side surface of the crown-shaped retainer, wherein the other side surface between the adjacent pockets is opposite to the opening side of the pocket. The notch is positioned so as to at least partially overlap the bearing raceway groove, and at the same time, extends along the inside of the raceway groove on one side where the pocket opens. Crown-type cage characterized by being flat.