JPH08114233A - Ball bearing - Google Patents

Abstract

PURPOSE: To provide a ball bearing capable of maintaining a proper amount of lubricant, stabilizing bearing friction torque at a fixed value and preventing a retainer from the generation of abnormal sounds. CONSTITUTION: In a ball bearing having a race guide type of a retainer 3 the side wall of a pocket 3P in the retainer 3 has a cylindrical central part 3a while at least one of the outside 3b and inside 3c of the central part is formed into a portion of a spherical or conical surface. When an eccentric clearance exists between the retainer 3 and the shoulder part of an inner ring or an outer ring, the side wall is formed such that still small clearance is produced between a ball 4 and the end of the pocket 3P in the retainer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball bearing equipped with a cage of a bearing ring guide type, and particularly to a ball bearing in a pocket by making lubricant (grease, oil) retained in the cage pocket appropriate. The present invention relates to a ball bearing having improved lubricity and lubricity of the contact portion between the ball and the inner / outer ring.

[0002]

2. Description of the Related Art A small diameter ball bearing is used for a driving motor shaft of a hard disk device or a floppy disk device for personal computers or word processors. There are two types of ball bearing guides for synthetic resin cages: rolling element guide type that guides with rolling elements (balls) and inner ring or outer ring guide type that guides with an inner ring or outer ring. The lubricant (grease) filled in the cage pocket over time
The friction torque of the bearing gradually decreases depending on the amount of oil and oil) and becomes almost constant. In the pocket shape for holding the balls of such a cage, balls arranged between the outer ring 11 and the inner ring 12 as shown in FIG. 7 and FIG. 8 which is a sectional view taken along the line BB of FIG. The inner wall of the pocket 13P of the retainer 13 that holds 14 is a flat cylindrical shape, and the outer ring 21 and the inner ring 22 are as shown in FIG. 9 and FIG. 10 which is a sectional view taken along the line CC of FIG. The pocket 23 of the cage 23 disposed between
The inner wall of P may be spherical. Many of the inner ring or outer ring guide type retainers have a cylindrical pocket, and many of the rolling element guide type retainers have a spherical pocket.

[0003]

As described above, in the ball bearing, the lubricant filled in the cage pocket with time is stable and the friction torque is constant when the lubricant gradually decreases from the beginning with time. Is desirable. However, in the cage of the inner ring 12 (or outer ring 11) guide type having the cylindrical pocket 13P shown in FIGS. 7 and 8, the ball surface-raceway surface-pocket surface-ball surface circulates and stays in the pocket. Since there is a large amount of the lubricant G as it is, the friction torque of the bearing poses a serious problem as compared with a rolling element guide type bearing having spherical pockets. That is, in the bearing of the cage of the orbital ring guide type having the cylindrical pocket, the balls come into contact with each other at the center of the pocket, and there is often no scraping action, and the torque does not decrease even after a lapse of time. on the other hand,
In the rolling element guide type cage 23 shown in FIGS. 9 and 10, the excess lubricant G adhering to the surface of the ball 24 is scraped off by the edge portion of the spherical pocket 23P and adhered to the inner peripheral surface or the outer peripheral surface of the cage. However, it does not affect the torque, and the viscous resistance of the lubricant on the ball or bearing contact portion decreases with the passage of rotation time, and the torque decreases as well. When the scraping action progresses excessively at high speed, an oil film is cut off at the pocket edge portion and the ball surface, resulting in abnormal noise due to poor lubrication. The present invention has been made in view of the above problems, and a ball bearing capable of maintaining an appropriate amount of lubricant to stabilize the bearing friction torque at a constant value and preventing occurrence of abnormal noise of a cage. The purpose is to provide.

[0004]

In order to solve the above-mentioned problems, the present invention provides a ball bearing having a cage of a guide ring type, wherein the side wall of the pocket of the cage has a cylindrical central portion. In addition, at least one of the outside and the inside of the central portion is formed so as to be a part of a spherical surface or a conical surface. Further, the spherical or conical surface portion formed on the side wall of the pocket of the cage does not come into contact with the ball when eccentric due to a gap existing between the cage and the shoulder portion of the inner ring or the shoulder portion of the outer ring. It is characterized in that it has a shape to keep it.

[0005]

When the ball bearing is used as the above and other means, the lubricant filled in the pocket of the cage is partially scraped off during rotation and the rest remains, but the conventional cage having a cylindrical pocket is used. By comparison, the amount of lubricant scraped is greater than that of the cylindrical pocket and less lubricant is left in the pocket. Also, compared to the cage with the conventional spherical pocket, the amount of lubricant scraped is less than that of the spherical pocket,
Therefore, the amount of lubricant remaining in the pocket increases. Initially, this ball bearing has a large friction torque due to the lubricant filled in the pocket of the cage, but eventually decreases and stabilizes at a constant friction torque. Further, according to the above means, it is possible to scrape off the excess lubricant (grease, oil) while leaving a slight clearance at the edge of the spherical surface or the conical surface of the cage pocket.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. 1 is a part of an axial sectional view of a ball bearing of the present invention, FIG. 2 (A) is a sectional view taken along the line AA of FIG. 1, and FIG. 2 (B) is a part of a pocket portion of a cage. FIG. This ball bearing is composed of an outer ring 1, an inner ring 2, a synthetic resin cage (in this case, a crown cage) 3, and a ball 4,
The cage 3 is of an inner ring guide type that is guided to the inner ring 2 by a guide portion 3d (however, it may be an outer ring guide type).
The side wall of the pocket 3P of the cage 3 of the ball bearing is a partially enlarged view of the pocket 3P portion of the cage 3 shown in FIG.
As shown in Fig. 3, the central portion 3a is cylindrical and the outer portion 3b is
And the inner portion 3c is formed of three spherical parts. Alternatively, the outer portion 3b or the inner portion 3c of the pocket 3P may be a part of a conical surface. Alternatively, one of the outer side portion 3b and the inner side portion 3c may be a spherical portion or a conical surface portion, and the other may be a cylindrical shape in which the central portion 3a is extended as it is.

FIG. 3 is a sectional view of the ball bearing of the present invention, showing a state in which a cage 3 holding balls 4 is arranged between an outer ring 1 and an inner ring 2. In the case of the bearing of the inner ring guide type, the cage 3 is rotated by the frictional force on the guide surface (shoulder portion) 2a of the inner ring 2, so that the balls 4 come into contact with each other on the side surface opposite to the rotation direction of the pocket 3P. Thus, even when the balls 4 come into contact with the wall surface of the pocket 3P of the cage 3, the balls 4 and the outer portion 3
b and the ends of the inner part 3c so that a certain "clearance" is formed between the outer part 3b and the inner part 3c.
Is formed into a spherical shape or a conical surface shape.

FIG. 4 (A) shows the bearing in a state where the cage 3 is eccentric by the clearance between the cage 3 and the inner ring 2, and FIG. 4 (B) is an enlarged view of part P of FIG. 4 (A). That is, as shown in these figures, even if the cage 3 is eccentric by the clearance existing between the retainer 3 and the shoulder 2a of the inner ring 2, the balls 4, the outer portion 3b, and the inner portion 3c are still formed.
The outer portion 3b and the inner portion 3c are formed into a spherical or conical surface having a diameter larger than that of the cylindrical portion of the pocket so that a certain "clearance" is formed between the outer portion 3b and the end portion of the pocket. Formed in part.

As described above, in the ball bearing according to the present invention, the inner wall of the pocket 3P of the cage 3 is formed by a cylindrical central portion 3a and a spherical portion or a conical portion, and an outer portion 3b and an inner portion. It is divided into three parts of the portion 3c, and even if the cage 3 is eccentric, a slight "clearance" is formed between the ball and the inner and outer peripheral ends of the pocket 3P. . As a result, the lubricant G filled in the pocket 3P
Although a part of (grease, oil) is scraped off during rotation and the rest remains, the amount of the lubricant G scraped off is larger than that of a cage having a conventional cylindrical pocket. More than one and less lubricant G remains in the pocket. Further, as compared with the conventional cage having spherical pockets, the lubricant G scraped off is used.
Is less than that of the spherical pocket, and thus the amount of lubricant G remaining in the pocket is greater. With this ball bearing, the surplus lubricant G can be scraped off while leaving a slight clearance at the edge portion of the spherical surface of the cage pocket. Thus, this ball bearing initially has a large friction torque due to the lubricant filled in the pocket 3P of the cage 3, but eventually decreases and stabilizes at a constant friction torque.

Next, using the ball bearing of the present invention, a conventional ball bearing having a retainer having a cylindrical pocket, and a ball bearing having a retainer having a spherical pocket, these are used. The test results of measuring the rotational torque (friction torque) generated in the ball bearing will be described. In this example,
The ball bearing of the present invention, that is, a ball provided with a cage 3 having a pocket 3P divided into three parts, that is, a cylindrical central part 3a, an outer part 3b having a spherical part, and an inner part 3c. The ball bearing (see FIGS. 1 and 2) is a “ball bearing 6”, and the ball bearing (see FIGS. 7 and 8) provided with the cage 13 having the cylindrical pocket 13P is a “ball bearing 7”. The ball bearing (see FIGS. 9 and 10) provided with the cage 23 having the pockets 23P formed therein is referred to as a “ball bearing 8”.

FIG. 5A is a plan view showing the structure of an apparatus for measuring the rotational torque (friction torque) of the ball bearing.
(B) is the front view. Reference numeral 30 is a rotary housing, and the outer rings of the ball bearing 6 (ball bearing 7 or ball bearing 8, hereinafter referred to as ball bearing 6 etc.) are fitted into the upper and lower two positions of the internal space 30a via spacers 31. . The ball bearings 6 and the like arranged on the lower side of the rotary housing 30 are supported by the step portion of the rotary housing 30, and the ball bearings 6 arranged on the upper side of the rotary housing 30 are fixed by a fixing ring 32. As a result, the upper and lower ball bearings 6 etc.
It is fixed within 0. A shaft 33 is fitted to the inner rings of the upper and lower ball bearings 6 and the like. A spring 35 is arranged above the shaft 33. The spring 35 is provided with a spring support 34 arranged on the inner ring end surface of the upper ball bearing 6 and the like, and a collar nut 36 screwed onto the shaft 33. It is held by the collar portion 36a. A steel wire 40 connected to a dynamic strain gauge 41 is fixed to the outer peripheral surface of the collar portion 36a of the collar nut 36. The distortion thus generated is amplified by the amplifier 42 and recorded by the recorder 43.

In the rotational torque measuring device having the above structure, the rotary housing 30 has an arrow P as shown in FIG. 5 (B).
5A, the shaft 33 is twisted along with the arrow Q, as shown in FIG. The power at that time
Fgf is attached to the outer peripheral surface of the collar nut 36 through a dynamic strain gauge 41.
Is generated in the tangential direction, the rotational torque T (gf · cm) can be measured as T = F · r, where r (cm) is the distance to the center of the shaft 33.

FIG. 6 shows the rotational torque (friction torque) described above.
It is a figure which shows the measurement result of the rotational torque of three types of ball bearings measured by the measuring device. The dimensions of common parts of these ball bearings are as follows: inner ring inner diameter: 5 mm, outer ring outer diameter: 13 mm, inner / outer ring width: 4 mm, ball diameter: 2 mm, number of balls・ ・ ・ ・ 8 pieces, pitch circle diameter ・ ・ ・ 9mm
Is. FIG. 6 (A) shows a test result when the "ball bearing 6" of the present invention is used. According to the test result of the ball bearing 6, the initial value was 6 (gf · cm) at the time of rising, but after 3 minutes, it was constant at about 3.5 (gf · cm). FIG. 6 (B) shows the test results when the "ball bearing 7" provided with the conventional cage having a cylindrical pocket is used. According to the test result of the ball bearing 7, the initial rise was 7.8 (gf · cm), but after 3 minutes, it was almost constant at 7 (gf · cm). FIG. 6 (C)
Shows the test results when the "ball bearing 8" provided with a conventional cage having a spherical pocket is used. According to the test result of the ball bearing 8, when the ball bearing 8 is initially raised,
It was 8 (gf · cm), but about 3 minutes later, it was about 2.8.
It became constant at (gf · cm). As is clear from these test results, in the ball bearing 7 provided with the retainer having the cylindrical pocket 13P formed therein, the rotational torque was not so much reduced even from the beginning of the rising, and the spherical pocket 23P was formed. In the ball bearing 8 equipped with a ball bearing, the reduction of the rotational torque at the time of stability is large as compared with the beginning. On the other hand, in the ball bearing of the present invention, the decrease in rotational torque at the time of stability is less than that of the ball bearing provided with the cage having the spherical pocket, compared to the beginning of the rising, but it is This shows that a certain amount is stably held in the pocket 3P.

[0014]

Since the ball bearing of the present invention is constructed as described above in detail, the lubricant retained in the pocket of the cage is the lubricant retained in the cylindrical pocket of the cage of the conventional ball bearing. Less and friction torque can be reduced. Further, the lubricant that stays in the pocket of the cage of the ball bearing can be retained more than the lubricant that stays in the spherical pocket of the cage of the conventional ball bearing, so that high speed rotation and high viscosity grease can be obtained. When using, it is possible to prevent abnormal noise of the cage caused by poor lubrication.

[Brief description of drawings]

FIG. 1 is a part of an axial sectional view of a ball bearing of the present invention.

2 (A) is a sectional view taken along the line AA of FIG.
FIG. 2B is a partially enlarged view of the pocket portion of the cage according to the present invention.

FIG. 3 is a sectional view of the ball bearing of the present invention, showing a state in which a cage holding balls is arranged between an outer ring and an inner ring.

4 (A) is a sectional view of the bearing in a state in which the cage is eccentric by the clearance existing between the cage and the inner ring, and FIG. 4 (B) is an enlarged view of part P of FIG. 4 (A). .

5 (A) is a plan view showing the configuration of an apparatus for measuring the rotational torque (friction torque) of a ball bearing, and FIG.
(B) is the front view.

FIG. 6 (A) is a diagram showing test results when the “ball bearing 6” of the present invention is used, and FIG. 6 (B) is a cage having a conventional cylindrical pocket. FIG. 6 is a diagram showing test results in the case of using the “ball bearing 7” provided with FIG.
(C) is a diagram showing a test result in the case of using a "ball bearing 8" including a conventional cage having a spherical pocket.

FIG. 7 is a part of an axial sectional view of a conventional ball bearing having a cage having a cylindrical pocket.

8 is a cross-sectional view taken along the line BB of FIG.

FIG. 9 is a part of an axial sectional view of a conventional ball bearing having a cage having spherical pockets formed therein.

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

[Explanation of symbols]

 1 Outer ring 2 Inner ring 3 Retainer 3P Retainer pocket 3a Central part of pocket side wall 3b Outer part of pocket side wall 3c Inner part of pocket side wall 4 Ball G Lubricant 6 Ball bearing 7, 8 Ball bearing

Claims (2)

[Claims] 1. A ball bearing having a cage of a bearing ring guide type, wherein a side wall of a pocket of the cage has a cylindrical central portion and at least one of an outer side and an inner side of the central portion is spherical or conical. A ball bearing characterized by being formed so as to be a part of a plane. 2. The spherical or conical surface portion formed on the side wall of the pocket of the cage is not eccentric to the ball when the cage is eccentric due to a gap existing between the cage and the shoulder portion of the inner ring or the shoulder portion of the outer ring. The ball bearing according to claim 1, wherein the ball bearing has a shape that maintains contact.