JPH08277843A - Crown type cage for ball bearing - Google Patents

Abstract

PURPOSE: To fill a sufficient quantity of grease in a cage from the anti-pocket side without sticking the grease to extra parts such as an outer ring raceway. CONSTITUTION: First recessed parts 13, 13 long in the circumferential direction are formed at the anti-pocket side end face of the main part 8a of a cage 7a. Second recessed parts 15, 15 over the axial direction are formed at parts between the adjacent pocket. Grease discharged from a filling nozzle is led to the pocket formed side through the first recessed parts 13, 13 and the second recessed parts 15, 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The crown type cage for ball bearings according to the present invention is
For example, hard disk drive (HDD), laser beam printer (LBP), video tape recorder (V
(TR) and the like, such as a spindle motor incorporated in a ball bearing for supporting various rotating parts such as a spindle motor.

[0002]

2. Description of the Related Art A ball bearing as shown in FIG. 14, for example, is widely used for supporting various rotating parts such as a bearing part of a spindle motor for HDD, LBP and VTR. In this ball bearing, an inner ring 2 having an inner ring raceway 1 on the outer peripheral surface and an outer ring 4 having an outer ring raceway 3 on the inner peripheral surface are concentrically arranged, and a plurality of inner ring raceways 1 and 3 are provided between the inner ring raceway 1 and the outer ring raceway 3. It is configured by rolling balls 5 and 5. The outer peripheral edges of circular ring-shaped shield plates 6 and 6 are locked to the inner peripheral surfaces of both ends of the outer ring 4, respectively, so that the grease existing in the balls 5 and 5 installation portions is exposed to the outside by both shield plates 6 and 6. It prevents leakage or dust that floats outside from entering this installation area. The plurality of balls 5, 5 are rotatably held by a cage 7. As a sealing device,
A contact type seal plate may be used in place of the non-contact type shield plates 6, 6.

In addition, like a spindle motor for HDD,
As the cage 7 incorporated in a small ball bearing (miniature bearing), generally, a crown type cage as shown in FIGS. 15 to 17 is used. In addition, FIG. 17 shows FF of FIG.
Although it is a cross-sectional view corresponding to a cross-section, parts other than cut portions are omitted for simplicity (the same applies to FIGS. 3 and 13 described later). This cage 7 has an annular main part 8 and this main part 8
A plurality of pockets 9 provided at equal intervals on one side in the axial direction of
9 and 9. Each pocket 9, 9 has a pair of elastic pieces 10, 10 arranged at a distance from each other, and a pair of elastic pieces 10, 1 on one surface of the main portion 8 (upper surface of FIG. 17).
And a concave surface portion 21 provided in a portion between 0.
Then, one ball 5 is held in each pocket 9 one by one so as to be rollable. The inner peripheral surfaces of the pockets 9, 9 thus configured are spherical concave surfaces or cylindrical surfaces as a whole. Such a cage 7 is integrally formed by, for example, injection molding synthetic resin.

Each of the balls 5 and 5 elastically pushes apart the distance between the tip edges of the pair of elastic pieces 10 and 10 that form the pockets 9 and 9, while the pair of elastic pieces 10 and 10 extends. 1
It is held between the pockets 9 and 9 by being pushed in between 0s. This work is performed after inserting the balls 5, 5 between the inner ring raceway 1 and the outer ring raceway 3 and arranging the balls 5, 5 at equal intervals in the circumferential direction. That is, the cage 7 is pressed against the balls 5, 5 provided between the inner ring raceway 1 and the outer ring raceway 3, and the balls 5, 5 are held in the pockets 9, 9 of the cage 7. The cage 7 holds the balls 5 and 5 in the pockets 9 and 9 in this manner, thereby placing the balls 5 and 5 between the inner ring raceway 1 and the outer ring raceway 3, respectively.
Holds rolling freely.

The ball bearing constructed and assembled as described above is filled with grease after the cage 7 is mounted. This grease filling operation is performed on the cage 7 with respect to the pockets 9 and 9
It is preferable to carry out from the side where the is provided (the upper side in FIG. 14).
The reason for this is that the grease adheres to the pockets 9 and 9 forming side having a relatively complicated shape (particularly the portions 22 and 22 between the adjacent pockets 9 and 9) in a relatively large amount and is stable for a long period of time. This is because the lubricating performance can be exhibited. Immediately after the start of use, only the low-viscosity lubricating oil component exuded from the grease adheres to the rolling surfaces of the inner and outer races 1, 3 and balls 5, 5 (the high-viscosity component Operation of the ball bearing is stable (immediately after the ball bearing is started to be used (immediately after the relative rotation between the inner ring 2 and the outer ring 4 is started), the torque required for the relative rotation between the inner ring 2 and the outer ring 4 is reduced. This is because of this.

However, depending on the structure of the ball bearing, the grease cannot be filled from the side where the pockets 9, 9 are provided,
The side where the pockets 9 and 9 are not provided (non-pocket side, FIG. 1)
It may be necessary to start from the bottom (4). For example, FIG. 18 described in Japanese Utility Model Publication No. 7-6523.
In the case of a double-row ball bearing having the structure shown in Fig. 19,
As shown in FIG.
Must be opposed to each other, and the grease 12 must be sent from the filling nozzle 11 over the main portion 8 to the pocket 9 side. In such a case, conventionally, the grease 12 is discharged from the filling nozzle 11 toward the outer ring raceway 3, and the grease 12 is attached to the outer ring raceway 3. The grease 12 adhering to the outer ring raceway 3 has a high viscosity except for components necessary for lubrication after adhering to the rolling surfaces of the balls 5 and 5 and the inner ring raceway 1 as the balls 5 and 5 roll. The component is the part 2 between
2, 22, etc. are collected in the concave portion of the retainer 7.

In this way, when the grease 12 once attached to the outer ring raceway 3 is collected in the concave portion on the surface of the cage 7 with the operation of the ball bearing, the operation is started after the ball bearing is started to be used. It takes a relatively long time to stabilize. More specifically, the inner ring and outer ring raceways 1, 3 immediately after the ball bearing is started.
Since the grease 12 including the high-viscosity component adheres to the rolling surfaces of the balls 5 and the balls 5, (excessive grease may cause
Portions 22, 2 between two adjacent pockets 9, 9
The torque required to rotate the inner ring 2 and the outer ring 4 relative to each other increases until the inner ring 2 and the outer ring 4 are caught in a recessed portion such as 2 and settles down. For example, the rotation speed of the spindle motor does not reach the regulation and becomes unstable. Power consumption increases.

In view of such circumstances, conventionally, the following structure is used to make it easier for the grease filled from the non-pocket side to reach the pocket side. In the structure described in this publication, in the portion between the pockets that are circumferentially adjacent to each other on the outer peripheral surface of the pocket, one end edge of the outer peripheral surface in the axial direction to the other end edge. It forms a concave groove reaching to. The grease discharged from the filling nozzle located on the side opposite to the pocket is held in these concave grooves, and the lubricating oil component is retained by the use and the inner ring, both outer ring raceways 1, 3 and balls 5, 5
Oozes on the rolling surface of. In the structure described in this publication, the outer diameter of the pocket is set to be slightly larger than the pitch edge of the ball, and the outer peripheral surface of the cage and the inner peripheral surface of the outer ring are separated. In addition, a sufficient gap is formed to allow grease to flow. The grease discharged from the filling nozzle located on the side opposite to the pocket is retained in this gap portion, and the lubricating oil component seeps out to the rolling surfaces of the inner ring, outer ring raceways 1, 3 and balls 5, 5 with use. .

[0009]

In the case of the above structure, there is no problem in holding the grease discharged from the filling nozzle located on the side opposite to the pocket side in a necessary place, but there is a new problem as follows. Occurs. First, in the case of the structure of (1), it is necessary to align the discharge port of the filling nozzle with the end opening of the concave groove. However, it is unavoidable that the grease filling operation becomes troublesome because positioning of the cage in the circumferential direction is required for alignment. If the filling operation is started without aligning the grease, only a small amount of grease discharged from the discharge port adheres to the end face of the cage on the side opposite to the pocket, so that sufficient lubrication performance cannot be maintained for a long period of time.

Further, in the case of the above structure, since the grease adheres not only to the cage but also to the outer ring raceway, there remains a cause of unstable operation immediately after the start of use. In addition, since the engagement between the pocket and the ball is reduced, the retainer in the radial direction must be positioned by the inner ring guide, which makes it difficult to reduce the rotational torque of the ball bearing. That is, when the ball bearing is operated at a high speed, it is necessary to position the retainer in the radial direction in order to prevent the retainer from oscillating due to displacement in the radial direction. As a structure for positioning the retainer in the radial direction, the outer ring guide that brings the outer peripheral surface of the cage and the inner peripheral surface of the outer ring into close proximity, and the inner ring guide that brings the inner peripheral surface of the retainer and the outer peripheral surface of the inner ring into close proximity to each other And a ball guide for engaging the rolling surface of the ball with the inner surface of the pocket. Among them, a ball guide is a structure in which friction is small when the ball bearing is rotated at high speed and power loss in the ball bearing portion is small (rotational resistance of the ball bearing is small).

For example, in the case of a miniature bearing for an HDD incorporated in a portable computer, it is preferable to employ the above ball guide in order to reduce power loss and power consumption as much as possible. However, if the outer diameter of the retainer is small, such as in a miniature bearing, which is originally small, the thickness of the retainer in the radial direction is considerably reduced. As a result, when materials, molding methods, etc. are compared under the same conditions, when a ball guide is adopted with the above structure, compared with a cage having a sufficient thickness dimension in the radial direction, It is disadvantageous in terms of durability.

In addition to this, as a crown type retainer, one having a structure in which a recess is provided in a part to form a grease reservoir is known. However, the structure that does not use the uneven shape of the pocket formation part cannot secure a sufficient volume of the recess, and the amount of grease attached to the cage is small, so sufficient durability is secured over a long period of time. It's difficult to do. The crown type cage for ball bearings according to the present invention has been made in view of the above circumstances in order to eliminate any of the above inconveniences.

[0013]

A crown retainer for ball bearings according to the present invention has an annular main portion and this main portion, similar to the conventional ball guide crown retainer for ball bearings described above. And a plurality of pockets provided on one side in the axial direction. Each pocket has a pair of elastic pieces spaced apart from each other,
The main portion is formed of an axial surface on one side and a concave surface portion provided between the pair of elastic pieces, and holds one ball in each pocket rotatably.

In particular, in the crown-type cage for ball bearings of the present invention, the first concave portion formed in the other axial surface of the main portion in the circumferential direction and the outer peripheral surface of the main portion are circular. A plurality of second recesses provided in the axial direction are provided between the pockets adjacent to each other in the circumferential direction. One end of each of the second recesses in the axial direction is opened in a part of the first recess, and the other end of the second recess in the axial direction is opened on one side of the main part in the axial direction.

[0015]

The function of the crown retainer for ball bearings according to the present invention, which is constructed as described above, for holding a plurality of balls in a rollable manner is the same as that of the above-described conventional crown retainer for ball bearings. It is similar to the case. Particularly, in the case of the crown-type cage for ball bearings of the present invention, the grease filling from the non-pocket side to the pocket side can be easily performed without excessively adhering it to an extra portion such as the outer ring raceway. Therefore, immediately after the start of use, the relative rotation between the inner ring and the outer ring can be smoothly performed (with an extremely small rotational resistance) without being hindered by the stirring resistance of the grease.

In other words, the presence of the first concave portion that is long in the circumferential direction facilitates the alignment of the discharge port of the filling nozzle and the holder. Therefore, the grease discharged from the discharge port of the filling nozzle can be guided from the first concave portion to the pocket side through the second concave portion without troublesome filling work. Since the grease is sent from the side opposite the pocket to the side of the pocket through the second concave portion, the grease is unlikely to adhere to extra portions such as the outer ring raceway. Therefore, a sufficient amount of grease can be adhered to the cage without adhering grease to the outer ring raceway, the initial characteristics can be improved, and stable lubrication performance can be obtained over a long period of time.

Further, the thickness dimension of the pocket forming portion of the cage in the radial direction can be made sufficiently large if necessary. Therefore, if necessary, a sufficient margin for engagement between the inner surface of each pocket and the rolling surface of the ball can be secured, and the engagement between these inner surface and rolling surface enables positioning of the cage in the radial direction. . As a result, it becomes possible to reduce the rotational resistance of the ball bearing by using the cage as a ball guide and to sufficiently secure the durability of the ball guide state, if necessary.

[0018]

1 to 10 show a first embodiment of the present invention. In addition, the feature of the crown type cage for ball bearings of the present invention is that even when performing the grease filling work from the opposite side of the pocket,
This grease has a structure that ensures that it reaches the side of the pocket, and the other structures and operations are the same as those of the conventional structure described above. Therefore, the same parts are designated by the same reference numerals to omit or simplify the overlapping description, and the characteristic parts of the present invention will be mainly described below.

The cage 7a of the present invention is integrally formed by injection molding a synthetic resin. In order to configure the cage 7a, one side in the axial direction of the main portion 8a formed in an annular shape (front side in FIG. 1, lower side in FIG. 3, upper side in FIG. 4, FIG. 6, 7,
On the left side of 10), each pair of elastic pieces 10,
A plurality of pockets 9, 10 are formed.
Further, on the other surface in the axial direction of the main portion 8a (the front surface in FIG. 2, the upper surface in FIG. 3, the lower surface in FIG. 4, the right surface in FIGS. 6, 7 and 10), each has an arc shape long in the circumferential direction. The first recesses 13, 13 of
It is formed intermittently. In the case of the illustrated embodiment, the inclined surfaces 14, 14 are provided at both circumferential end portions of each first recess 13, 13.
By forming the above, the first concave portions 13 and 13 are gradually shallowed at both ends thereof.

On the other hand, second recesses 15 and 15 are respectively formed in the axial direction (FIGS. In the front and back direction, the vertical direction in FIGS. 3 and 4, and the horizontal direction in FIGS. 6, 7, and 10). One end of each of these second recesses 15 and 15 in the axial direction (the front end of FIGS. 2, 5 and 9, the upper end of FIG.
(The lower end of FIG. 6, the right end of FIGS. 7, 7 and 10) is the first concave portion 1 described above.
An opening is made in the intermediate portion in the circumferential direction of Nos. 3 and 13. Therefore,
The inside of each of these first recesses 13 and 13 and each of the above second recesses 1
5 and 15 communicate with each other at the circumferential intermediate portions of the second recesses 15 and 15. Also, each of the second recesses 1
The other axial ends of 5 and 15 (the front end in FIG. 1, the lower end in FIG. 3, the upper end in FIG. 4, the left end in FIGS. 6, 7 and 10) are arranged on one side in the axial direction of the main portion 8a in the circumferential direction. An opening is made at a portion 22, 22 between the adjacent pockets 9, 9.

The retainer 7a constructed as described above is shown in FIG.
6 to 6, an inner ring 2, an outer ring 4, and a plurality of balls 5 and 5 are combined to form a ball bearing. In this way, the other member 2,
When the cage 7a rotatably holds the plurality of balls 5 and 5 in a state where the ball bearing is configured by being combined with the ball bearings 4 and 5, the operation itself is the same as that of the prior art shown in FIGS. This is similar to the case of the retainer 7 of. In particular, the cage 7a of the present invention
In this case, from the non-pocket side to the pocket side (from the back surface side to the front surface side of FIG. 1, the front surface side to the back surface side of FIGS. 2, 5, and 9, the top to bottom of FIG. 4, the bottom to top of FIG. (From 10 right to left)
Can be easily filled with grease.

That is, when the ball bearing in which the constituent members 2, 4 and 5 are combined as shown in FIGS. 5 to 6 is filled with grease, the filling having the discharge ports 16 and 16 as shown in FIG. 8 is performed. The nozzle 11a is opposed to the other axial surface (the back surface side in FIG. 1, the front surface side in FIG. 2) of the main portion 8a constituting the retainer 7a. The discharge ports 16 and 16 are formed at equal intervals in the circumferential direction so as to have the same pitch as the balls 5 and 5 and the first recesses 13 and 13. Further, an eaves portion 17 is provided on the end face of the filling nozzle 11a and around the discharge ports 16 and 16.
Is formed over the entire circumference.

When performing the filling operation, as shown in FIG. 7, when the positioning step portion 18 formed around the eaves portion 17 is abutted against the end surface of the outer ring 4, the above-mentioned discharge ports 16, 16 are formed.
Faces the first recesses 13 and 13, and the eaves 17 covers the periphery of the discharge ports 16 and 16 and the first recesses 13 and 13. These first recesses 13, 13 are long in the circumferential direction, and the length dimension of the discontinuous portion between the adjacent first recesses 13, 13 is limited. Therefore, the discharge port 1 of the filling nozzle 11a is
The positioning work for facing the first and second recesses 13 and 13 of the holder 7a to each other can be easily performed. Further, as will be described later, even if the discharge ports 16 and 16 and the first recesses 13 and 13 are slightly displaced from each other in the circumferential direction, the grease filling work can be practically performed without any problem.

In this way, the discharge ports 16, 16 and the first recess 1
In the state where the nozzles 3 and 13 are opposed to each other, the discharge ports 16 and 1
If grease 19 is discharged from 6,
Is the first recess 1 that is long in the circumferential direction, as shown in FIGS.
3 and 13, and further each of these first recesses 13,
13 is guided to the pocket side of the retainer 7a through the second recesses 15 and 15. Therefore, the discharge ports 16, 16 of the filling nozzle 11a can be filled without troublesome filling work.
The grease 19 discharged from the first concave portion 13,
It can be guided to the pocket side from 13 through the second concave portions 15 and 15. At this time, the excess grease 19 hardly adheres to the outer ring raceway 3.

In this way, as a result of the grease 19 being guided to the pocket side during the filling operation without adhering to the outer ring raceway 3, only the lubricating oil component exuded from the grease 19 immediately after the start of use of the ball bearing is the inner ring. , Adhere to the rolling surfaces of the outer ring raceways 1, 3 and balls 5, 5. Therefore, immediately after the ball bearing is started to be used, excess grease including a highly viscous component does not remain attached to the rolling surfaces of the balls 5 and 5 and both the inner ring and the outer ring raceways 1 and 3, so that the ball bearing is operated. Is stable. As a result,
The torque required to rotate the inner ring 2 and the outer ring 4 relatively decreases from the beginning, and for example, the rotation speed of the spindle motor is stabilized as specified, and power consumption can be reduced.

The surroundings of the discharge ports 16 and 16 are provided with the eaves portion 1.
Since it is covered with 7, the alignment between the retainer 7a and the filling nozzle 11a is incomplete, and the discharge ports 1
Even if the first and second concave portions 6 and 16 are slightly displaced from each other in the circumferential direction, most of the grease discharged from the respective discharge ports 16 and 16 is blocked by the eaves portion 17 to surround it. Without being scattered, the ink is received in the first recesses 13, 13 existing in the immediate vicinity of the discharge ports 16, 16. Therefore, the grease filling work can be carried out practically without any problems without strict alignment of the cage 7a and the filling nozzle 11a.

Further, the thickness dimension of the cage 7a in the radial direction is determined by the portion 2 between the pockets 9 which are adjacent to each other in the circumferential direction.
2, 22 becomes smaller in the portions where the second recesses 15 and 15 are formed, but the thickness of the portions where the pockets 9 and 9 are formed in the radial direction is sufficiently large. Therefore, the engagement margin between the inner surface (spherical concave surface) of each of the pockets 9 and 9 and the rolling surface of the balls 5 and 5 is sufficiently secured, and the engagement between the inner surface and the rolling surface causes the cage 7a to move. Positioning can be achieved in the radial direction. As a result, the rotation resistance of the ball bearing can be reduced by using the cage 7a as a ball guide. Moreover, since the engagement allowance can be sufficiently ensured, the engagement between the inner surface and the rolling surface is less likely to be disengaged even when worn, and the durability in the ball guide state can be sufficiently ensured.

Even if the retainer 7a and the filling nozzle 11a are not properly aligned with each other, and the discharge ports 16 and 16 and the first recesses 13 and 13 are slightly displaced from each other in the circumferential direction, In order to completely guide the grease discharged from the discharge ports 16 and 16 to the first recesses 13 and 13, FIG.
As shown in FIG.
It is also possible to form a groove 20 extending in the circumferential direction in the portion where 6 is formed. The concave groove 20 may be formed over the entire circumference, or in the vicinity of the discharge ports 16 and 16 (the discharge port 1).
6 and 16 and the first recesses 13 and 13 may be formed only in a sufficient length). If such a concave groove 20 is formed, the discharge ports 16 and 1 can be formed without considering the alignment between the retainer 7a and the filling nozzle 11a.
The grease discharged from 6 is completely removed from the first concave portion 13,
You can lead to 13.

Next, FIGS. 12 to 13 show a second embodiment of the present invention. In the case of the present embodiment, the first concave portion 13a is formed over the entire circumference on the other surface in the axial direction of the main portion 8b constituting the cage 7b (the front surface in FIG. 12, the upper surface in FIG. 13). There is. Since the first concave portion 13a is formed over the entire circumference in this manner, it goes without saying that when the filling nozzle 11b having the concave groove 20 as shown in FIG. 11 is used, the concave groove shown in FIG. Even when using the filling nozzle 11a without
Grease discharged from each of the discharge ports 16 and 16 can be completely guided to the first recess 13a without considering the alignment between the b and the filling nozzle 11a. Other configurations and operations are similar to those of the first embodiment described above.

[0030]

Since the crown type cage for ball bearings according to the present invention is constructed and operates as described above, the initial performance of the ball bearing incorporating the cage and further various equipments incorporating this ball bearing can be obtained. It is possible to stabilize and save energy and ensure durability.

[Brief description of drawings]

FIG. 1 is a front view of a cage according to a first embodiment of the present invention viewed from a pocket forming side.

FIG. 2 is a rear view of the same.

3 is a sectional view taken along line AA of FIG.

FIG. 4 is a view on arrow B of FIG.

FIG. 5 is a view showing a state in which a ball bearing is configured, viewed from the same direction as FIG. 2.

6 is a cross-sectional view taken along line CC of FIG.

FIG. 7 is a view similar to FIG. 6, showing a state in which a filling nozzle for filling grease is abutted.

8 is a view of the filling nozzle as viewed from the left side of FIG. 7.

FIG. 9 is a view similar to FIG. 5, showing a state of being filled with grease.

FIG. 10 is a sectional view taken along line DD of FIG. 9;

FIG. 11 is a view similar to FIG. 7, showing another example of the filling nozzle.

FIG. 12 is a rear view of the cage according to the second embodiment of the present invention viewed from the side opposite to the pocket.

13 is a sectional view taken along line EE of FIG.

FIG. 14 is a sectional view showing a first example of a ball bearing in which a crown type cage is incorporated.

FIG. 15 is a half plan view showing an example of a conventional cage.

FIG. 16 is a perspective view of the same.

FIG. 17 is a cross-sectional view showing the FF cross section of FIG. 16 except for the cut portion.

FIG. 18 is a sectional view showing a second example of a ball bearing incorporating a crown type cage.

FIG. 19 is a sectional view showing a state where the ball bearing of the second example is filled with grease.

[Explanation of symbols]

 1 Inner ring track 2 Inner ring 3 Outer ring track 4 Outer ring 5 Ball 6 Shield plate 7, 7a, 7b Retainer 8, 8a, 8b Main part 9 Pocket 10 Elastic piece 11, 11a, 11b Filling nozzle 12 Grease 13, 13a First recess 14 Inclined surface 15 Second concave portion 16 Discharge port 17 Eaves portion 18 Positioning step portion 19 Grease 20 Concave groove 21 Concave surface portion 22 Part between

Claims (1)

[Claims] 1. A ring-shaped main portion, and a plurality of pockets provided on one surface in the axial direction of the main portion, each pocket comprising:
It is composed of a pair of elastic pieces spaced apart from each other, and a concave surface portion provided on the axially one side of the main portion between the pair of elastic pieces. In a crown-type cage for ball bearings, which are rotatably held one by one, in a circumferentially long first concave portion formed on the other axial surface of the main portion, and the main portion of the main portion. A plurality of second recesses provided in the axial direction are provided between the pockets that are circumferentially adjacent to each other on the outer peripheral surface, and one axial end of each second recess is formed in a part of the first recess. A crown type cage for a ball bearing, wherein the other axial end of each second recess is opened on one axial side of the main portion.