JP2000074074A - Ball bearing - Google Patents

Abstract

(57) [Problem] To provide a ball bearing capable of suppressing torque such as starting torque and dynamic friction torque and suppressing a rise in cost. A deep groove ball bearing as a ball bearing includes an inner ring, an outer ring, and a ball. The inner ring 2 is formed in an annular shape so that the rotating shaft 5 is fixed to the inner peripheral surface. Outer ring 3
Is formed in an annular shape having an inner diameter larger than the outer diameter of the inner ring 2. The ball 4 has an outer peripheral surface 6 of the inner ring 2 and an inner peripheral surface 7 of the outer ring 3.
And is rotatably provided between the inner ring 2 and the outer ring 3. A groove 8 having an arc-shaped cross section is formed in the outer peripheral surface 6 of the inner ring 2 along the circumferential direction. An inner peripheral surface 7 of the outer race 3 is formed with a groove 9 having an arc-shaped cross section along the circumferential direction. The groove 9 has a radius of curvature exceeding 53% of the diameter da of the ball 4 and 65
% Or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball bearing used for a storage device of an electronic / information device.

[0002]

2. Description of the Related Art A relatively small-diameter and small-sized deep groove ball bearing or angular ball bearing is used for a spindle motor or the like used in a storage device such as a porcelain disk device of an electronic / information device.

[0003] In the above-mentioned deep groove ball bearings and angular ball bearings, grease used as a lubricant has been improved in order to reduce torque such as starting torque and dynamic friction torque. 6-1
The torque reduction method disclosed in 8730 and the like has been applied.

In the method for reducing torque disclosed in Japanese Patent Application Laid-Open No. 9-79266, grease is sealed on each of the inner and outer peripheral surfaces of a cage. The torque described above is reduced by suppressing the resistance when the grease flows into the rolling element rolling grooves of the inner and outer races and the rolling element rolls.

On the other hand, in the method of reducing torque disclosed in Japanese Utility Model Laid-Open No. 6-18730, a solid lubricating member made of resin or the like and impregnated with oil is provided inside a bearing. Oil is leached from the lubricating member to reduce the above-mentioned torque.

In general, in the above-described ball bearings such as the deep groove ball bearing and the angular ball bearing, when an assembling error in assembling the inner and outer rings and the ball increases, the inner and outer rings and the ball come into contact with each other. The resulting elliptical contact surface may deviate from the predetermined positions of the grooves of the inner and outer rings. Further, in some cases, the elliptical contact surface may protrude from the groove.

If the elliptical contact surface protrudes from the groove, a portion where the surface pressure on the contact surface between the inner and outer rings and the ball is locally increased occurs, thereby shortening the life of the ball bearing and reducing wear. Is caused. For this reason, the ball bearing defines an assembly error such that the contact surface does not protrude from the groove, and defines a tolerance at the time of manufacturing the inner and outer rings and the ball.

[0008]

The above-described deep groove ball bearings and angular ball bearings used for storage devices of electronic and information devices and the like are provided with the above-mentioned torque in order to suppress the power consumed by the storage devices and the like. In recent years, the demand for reduction of the amount has been increasing.

In the improvement of grease used as a lubricant,
It is difficult to satisfy such a demand for torque reduction. On the other hand, as in the bearings disclosed in JP-A-9-79266 and JP-A-6-18730, torque is further reduced by minimizing lubricant entering the raceway surface. Is becoming difficult because of poor lubrication.

The above-described deep groove ball bearings and angular ball bearings are relatively small in diameter and small in size, so that the contact surfaces between the inner and outer rings and the balls do not protrude from the grooves. It is necessary to keep the tolerances small. For this reason, the cost of deep groove ball bearings, angular ball bearings, and the like used in storage devices of electronic and information devices has tended to rise.

Accordingly, it is an object of the present invention to provide a ball bearing which can suppress torque such as starting torque and dynamic friction torque and can suppress a rise in cost.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve the object, a ball bearing according to the first aspect of the present invention comprises an inner ring, an outer ring, and rolling between the inner ring and the outer ring. A ball provided on the contact surface of each of the inner ring and the outer ring with the ball, wherein the arc-shaped groove of the outer ring is formed in the arc-shaped groove along the circumferential direction. The ball is formed so that the radius is in the range of more than 53% and not more than 65% of the diameter of the ball.

The ball bearing according to the present invention described in claim 2 is:
An inner ring, an outer ring, and a ball rotatably provided between the inner ring and the outer ring. A groove having an arc-shaped cross section is formed along a circumferential direction on each of the contact surfaces of the inner ring and the outer ring with the ball. A ball bearing is characterized in that the arc-shaped groove of the inner ring is formed so that its radius of curvature is in the range of more than 52% and not more than 65% of the diameter of the ball.

The ball bearing of the present invention described in claim 3 is:
An inner ring, an outer ring, and a ball rotatably provided between the inner ring and the outer ring. A groove having an arc-shaped cross section is formed along a circumferential direction on each of the contact surfaces of the inner ring and the outer ring with the ball. In the ball bearing, each of the arc-shaped groove of the outer ring and the arc-shaped groove of the inner ring has a radius of curvature of 52 of the diameter of the ball.
% And in the range of 65% or less.

As described above, according to the ball bearing of the present invention, at least one of the inner ring groove and the outer ring groove has a curvature radius of JI.
The torque is reduced by making the radius of curvature larger than that defined by S (Japanese Industrial Standard). Furthermore, the ball bearing reduces the area of the contact surface between each of the inner and outer rings and the ball by increasing the radius of curvature of at least one groove of the inner and outer rings, and suppresses these contact surfaces from protruding from the grooves. are doing.

In general, it is known that the above-mentioned torque such as the starting torque and the dynamic friction torque is proportional to the area of an elliptical contact surface generated by the contact between the inner and outer rings and the ball. It is known that the area of the contact surface is reduced by increasing the radius of curvature of the grooves of the inner and outer rings. On the other hand, according to JIS (Japanese Industrial Standard), the radius of curvature of the groove of the inner ring is set to 52% or less of the diameter of the ball, and the radius of curvature of the groove of the outer ring is set to 53% or less of the diameter of the ball.

For this reason, in the ball bearing of the present invention, the radius of curvature of at least one of the grooves of the inner and outer rings is made larger than the radius of curvature specified by JIS (Japanese Industrial Standard), so that the contact between the inner and outer rings and the ball is made. Since the surface area is suppressed, the torque can be reduced.

In the ball bearing of the present invention, the area of the contact surface between each of the inner and outer rings and the ball is suppressed by increasing the radius of curvature of the groove. For this reason, it is difficult for these contact surfaces to protrude from the groove. Further, since the area of the above-mentioned contact surface is suppressed, the contact surface is unlikely to protrude from the groove even when the tolerance in manufacturing the inner and outer rings and the balls is increased. Therefore, it is possible to increase the tolerance of the inner and outer races and the balls, thereby suppressing a rise in cost.

Further, in the above-mentioned claim 3, the arc-shaped groove of the outer ring and the arc-shaped groove of the inner ring are respectively
It is desirable that the radius of curvature be in the range of 54% or more and 56% or less of the diameter of the ball. in this case,
It is possible to more reliably suppress the torque and to suppress a rise in cost.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. A deep groove ball bearing 1 as a ball bearing is a rolling bearing used for a spindle motor or the like of a storage device such as a porcelain disk device of an electronic / information device, and as shown in FIG. The ball 4 as a moving body is provided.

The inner ring 2 is formed in an annular shape, and a rotating shaft 5 indicated by a two-dot chain line Q in the figure is fixed to the inner peripheral surface thereof. 5 and is rotatable with respect to the outer ring 3.

The outer ring 3 is formed in an annular shape having an inner diameter larger than the outer diameter of the inner ring 2. The ball 4 is formed in a spherical shape, is in contact with the outer peripheral surface 6 of the inner ring 2 and the inner peripheral surface 7 of the outer ring 3, and is provided so as to roll freely between the inner ring 2 and the outer ring 3. The balls 4 do not transmit relative rotation between the inner ring 2 and the outer ring 3 to the outer ring 3 and the inner ring 2. Note that the outer peripheral surface 6 of the inner ring 2 and the inner peripheral surface 7 of the outer ring 3 form a contact surface described in this specification.

On the outer peripheral surface 6 and the inner peripheral surface 7 of the inner ring 2 and the outer ring 3, grooves 8 and 9 having an arc-shaped cross section are formed along the circumferential direction of the inner ring 2 and the outer ring 3, respectively. . Each of the grooves 8 and 9 is formed so as to have a groove shape along the ball 4.

A groove 8 formed on the outer peripheral surface 6 of the inner ring 2
And at least one of the grooves 9 formed on the inner peripheral surface 7 of the outer ring 3, the radius of curvature is formed larger than the radius of curvature specified by JIS (Japanese Industrial Standard).

The groove 9 of the outer ring 3 is JIS (Japanese Industrial Standard)
If the radius of curvature is larger than the radius of curvature defined by
It is formed in a range of more than 3% and 65% or less.

The groove 8 of the inner ring 2 is JIS (Japanese Industrial Standard)
If the radius of curvature is larger than the radius of curvature defined by
It is formed in a range of more than 2% and 65% or less.

When the grooves 8 and 9 of the inner and outer rings 2 and 3 are formed with a radius of curvature larger than the radius of curvature specified by JIS (Japanese Industrial Standard), each radius of curvature is a ball. More than 52% and 65% of the diameter da of 4
It is formed to have the following range. Further, in this case, it is desirable that the grooves 8, 9 of the inner and outer rings 2, 3 are formed so that the respective radii of curvature are in the range of 54% or more and 56% or less of the diameter da of the ball 4.

According to the above-described structure, at least one of the radii of curvature of the grooves 8, 9 of the inner and outer rings 2, 3 is defined by JIS or the like, and the radius of curvature of the groove of a ball bearing which is conventionally and generally used. It is formed larger. For this reason, the groove 8,
9, the area of the contact surface between the inner and outer rings 2, 3 and the ball 4 becomes smaller. Therefore, the torque such as the starting torque and the dynamic friction torque of the ball bearing 1 can be suppressed.

Further, since the radius of curvature of at least one of the grooves 8, 9 is formed larger than the radius of curvature of the conventional ball bearing, the area of the contact surface between the inner and outer rings 2, 3 and the ball 4 is reduced. In addition, the contact surfaces between the inner and outer rings 2 and 3 and the balls 4 hardly protrude from the grooves 8 and 9. For this reason, a reduction in the life of the ball bearing 1 can be suppressed, and the respective tolerances in manufacturing the inner and outer rings 2 and 3 and the ball 4 can be increased. Therefore, it is possible to suppress an increase in the cost of the ball bearing 1.

In the following, the balls 4 and the inner and outer races in the grooves 8 and 9 when the radius of curvature of the grooves 8 and 9 of the inner and outer rings 2 and 3 of the deep groove ball bearing 1 are examined to confirm the operation of the present invention. FIGS. 2 to 7 show changes in the area of the elliptical contact surface with the rings 2 and 3 and the contact pressure on the contact surface.

In this study, the deep groove ball bearing 1 is J
A deep groove ball bearing 695 specified by IS (Japanese Industrial Standard) B1513 is used, and the case where the assembly error of the deep groove ball bearing 1 is 0.1 degree is used. The assembling error is caused by a line segment L orthogonal to the axis P and passing through the groove bottom 8a of the groove 8 and a point O at which the line segment L intersects with the axis P as shown in FIG. 9 shows an angle θ formed by a line segment M passing through the groove bottom 9a of FIG.

FIG. 2 shows that the radius of curvature of the groove 8 of the inner race 2 is made constant at 52% of the diameter da of the ball 4 and the radius of curvature of the groove 9 of the outer race 3 is from 52% to 70% of the diameter da of the ball 4. The case where it changed is shown. FIG. 3 shows that the radius of curvature of the groove 9 of the outer ring 3 is fixed at 53% of the diameter da of the ball 4 and the radius of curvature of the groove 8 of the inner ring 2 is changed from 52% to 70% of the diameter da of the ball 4. Shows the case. FIG. 4 shows a case where the radii of curvature of the grooves 8 and 9 of the inner and outer rings 2 and 3 are changed from 52% to 70% of the diameter da of the ball 4.

The diamonds in FIGS. 2 to 4 indicate the surface pressure at the contact surface of the inner ring 2 with the ball 4, and the squares in FIGS. 2 to 4 indicate the surface pressure at the contact surface of the outer ring 3 with the ball 4. ing. The triangles in FIGS. 2 to 4 indicate the area of the contact surface of the inner ring 2 with the ball 4, and the crosses in FIGS. 2 to 4 indicate the area of the contact surface of the outer ring 3 with the ball 4. .

According to FIGS. 2 and 3, when the radius of curvature of the groove 8 of the inner ring 2 or the groove 9 of the outer ring 3 is constant, if the radius of curvature of the groove 9 of the outer ring 3 or the groove 9 of the inner ring 2 is increased, It became clear that the area of the elliptical contact surface with the ball 4 in the groove 9 of the outer ring 3 or the groove 8 of the inner ring 2 became smaller.

According to FIG. 4, when the radius of curvature of the grooves 8, 9 of the inner and outer rings 2, 3 is increased, the area of the contact surface between the inner and outer rings 2, 3 and the ball 4 in the grooves 8, 9 is reduced. It became clear that it went. Since the torque decreases as the area of the contact surface decreases, it is apparent that increasing the radius of curvature of at least one of the grooves 8, 9 of the inner and outer rings 2, 3 reduces the torque such as the starting torque and the dynamic friction torque. It became.

On the other hand, when the radius of curvature of the grooves 8 and 9 is increased in this way, the area of the contact surface with the ball 4 is reduced, and the surface pressure on these contact surfaces is increased, and the life of the bearing 1 itself is increased. The effect such as lowering is caused. For this reason, it is not preferable to make the curvature radii of the grooves 8, 9 extremely large.

The difference between the decrease in the area of the contact surface (decrease ratio) corresponding to the decrease in the torque and the increase in the surface pressure (increase ratio) on the contact surface corresponding to the decrease in the life is shown in FIG.
7 to FIG.

In FIGS. 5 to 7, the amount of decrease in the area of the contact surface (reduction ratio) means that the radius of curvature of the grooves 8 and 9 of the inner and outer rings 2 and 3 is 52% of the diameter da of the ball 4. Based on the area, the ratio of the area of the contact surface at each radius of curvature to this reference is shown. 5 to 7, the amount of increase in the contact pressure on the contact surface is based on the contact pressure when the radius of curvature of the grooves 8 and 9 of the inner and outer rings 2 and 3 is 52% of the diameter da of the ball 4. And the ratio of the surface pressure at each radius of curvature to this reference is shown.

That is, in FIG. 5 to FIG. 7, when the difference between the above-described decrease in the area of the contact surface (decrease ratio) and the increase in the surface pressure on the contact surface (increase ratio) is positive, This shows that the merit such as a decrease in the torque due to the decrease in the area of the contact surface is greater than the disadvantage such as a decrease in the life due to an increase in the pressure.

FIG. 5 shows the groove 8 of the inner race 2 shown in FIG.
Is constant at 52% of the diameter da of the ball 4 and the radius of curvature of the groove 9 of the outer race 3 is changed from 52% of the diameter da of the ball 4 to 7%.
The graph shows the difference between the above-described decrease in the area of the contact surface (decrease ratio) and the increase in the surface pressure at the contact surface (increase ratio) when the contact surface is changed to 0%.

FIG. 6 shows that the radius of curvature of the groove 9 of the outer ring 3 shown in FIG. 3 is made constant at 53% of the diameter da of the ball 4, and the radius of curvature of the groove 8 of the inner ring 2 is 52% of the diameter da of the ball 4. 5 shows the difference between the above-described decrease in the area of the contact surface (decrease ratio) and the increase in the surface pressure on the contact surface (increase ratio) when the ratio is changed from% to 70%.

FIG. 7 shows the above-mentioned contact surface when the radius of curvature of the grooves 8, 9 of the inner and outer rings 2, 3 shown in FIG. 4 is changed from 52% to 70% of the diameter da of the ball 4. It shows the difference between the amount of decrease in area (decrease ratio) and the amount of increase in surface pressure on the contact surface (increase ratio).

The diamonds in FIGS. 5 to 7 indicate the inner ring 2.
3 shows the difference between the amount of decrease in the area of the contact surface with the ball 4 (decrease ratio) and the amount of increase in the surface pressure on the contact surface (increase ratio). The squares in FIGS. 5 to 7 indicate the difference between the amount of decrease in the area of the contact surface of the outer ring 3 with the ball 4 (decrease ratio) and the increase in the surface pressure on the contact surface (increase ratio).

According to FIG. 5, if the radius of curvature of the groove 9 of the outer ring 3 is in the range of more than 53% and 65% or less of the diameter da of the ball 4, the balls 4 of the inner and outer rings 2, 3 will The difference between the decrease in the area of the contact surface (decrease ratio) and the increase in the contact pressure at the contact surface (increase ratio) is positive. It became clear that the merit such as a decrease in torque due to the reduction of the surface area was great.

According to FIG. 6, if the radius of curvature of the groove 8 of the inner ring 2 is more than 52% and not more than 65% of the diameter da of the ball 4, the balls 4 of the inner and outer rings 2 and 3 will be Since the difference between the decrease in the area of the contact surface (decrease ratio) and the increase in the surface pressure at the contact surface (increase ratio) is positive or close to zero, the life decreases due to the increase in the contact surface pressure, etc. It has become clear that the disadvantages such as a decrease in the torque due to the decrease in the area of the contact surface are greater than the disadvantages of the above, or the disadvantages such as a reduction in the life are very small.

According to FIG. 7, if the radii of curvature of the grooves 8, 9 of the inner and outer rings 2, 3 exceed 52% and 65% or less of the diameter da of the ball 4, respectively, the aforementioned inner and outer rings 2 , 3 because the difference between the decrease in the area of the contact surface with the ball 4 (decrease ratio) and the increase in the contact pressure at the contact surface (increase ratio) is positive or close to zero, the contact surface pressure increases. It became clear that the merit such as a decrease in the torque due to the decrease in the area of the contact surface was greater than the disadvantage such as a decrease in the life due to the amount, or the disadvantage such as a decrease in the life was very small.

Further, according to FIGS. 5 to 7, the radius of curvature of each of the grooves 8 and 9 of the inner and outer rings 2 and 3 is determined by the diameter d of the ball 4.
If it is not less than 54% and not more than 56% of a, there are disadvantages such as a reduction in life due to an increase in the contact surface pressure.
It has been clarified that the merits such as a decrease in torque due to a decrease in the area of the contact surface are particularly large.

As described above, the groove 9 of the outer ring 2 of the deep groove ball bearing 1
Is more than 53% of the diameter da of the ball 4 and 65%
By forming so as to fall within the range, the torque can be suppressed. Further, it is possible to suppress the contact surface from protruding from the groove 9, and the angle θ described above is set to 0.1.
The inner and outer rings 2 and 3
In addition, the manufacturing tolerance of the balls 4 can be increased, and the cost can be prevented from rising.

Further, by forming the radius of curvature of the groove 8 of the inner ring 3 of the deep groove ball bearing 1 so as to be more than 52% and 65% of the diameter da of the ball 4, torque can be suppressed. . Furthermore, since the contact surface can be prevented from protruding from the groove 8 and the above-mentioned angle θ may be a relatively large angle such as 0.1 °, the manufacturing tolerance of the inner and outer rings 2 and 3 and the ball 4 should be increased. Can be suppressed, and a rise in cost can be suppressed.

Further, by forming the radii of curvature of the grooves 8 and 9 of the inner and outer rings 2 and 3 of the deep groove ball bearing 1 so as to be more than 52% and 65% of the diameter da of the balls 4, torque can be reduced. Can be suppressed. Further, the contact surfaces are formed by grooves 8, 9
As a result, since the angle θ described above may be a relatively large angle such as 0.1 °, the manufacturing tolerance of the inner and outer rings 2 and 3 and the balls 4 can be increased, and the cost increases. Can be suppressed.

Although the present invention has been described with reference to the case where the present invention is applied to the deep groove ball bearing 1, the present invention is not limited to the deep groove ball bearing 1, but may be applied to other types of ball bearings such as angular ball bearings. By combining the curvature radii of the grooves of the inner and outer rings within the range of the present invention, it is possible to suppress the torque such as the starting torque and the dynamic friction torque and provide a low-cost bearing.

[0052]

According to the ball bearing of the present invention, since the radius of curvature of at least one of the grooves of the inner and outer rings is formed larger than the radius of curvature specified by JIS (Japanese Industrial Standard), torque can be reduced. It becomes possible.

Further, since the ball bearing of the present invention has a large radius of curvature, the contact surfaces between the inner and outer rings and the ball are suppressed. For this reason, it becomes difficult for these contact surfaces to protrude from the groove, and it is possible to increase the tolerance when manufacturing the inner and outer rings and balls. Therefore, it is possible to suppress a rise in cost.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a part of a deep groove ball bearing as a ball bearing according to an embodiment of the present invention.

FIG. 2 is a graph showing the change in the area and surface pressure of the contact surface between the inner and outer rings and the ball with respect to the change in the radius of curvature of the groove of the outer ring when the radius of curvature of the groove of the inner ring is constant in the deep groove ball bearing shown in FIG. FIG.

FIG. 3 is a graph showing the change in the area and surface pressure of the contact surface between the inner and outer rings and the ball with respect to the change in the radius of curvature of the inner ring groove when the radius of curvature of the groove of the outer ring is constant in the deep groove ball bearing shown in FIG. FIG.

FIG. 4 is a diagram showing changes in the area and surface pressure of the contact surface between the inner and outer rings and the ball due to changes in the radius of curvature of the grooves of the inner and outer rings in the deep groove ball bearing shown in FIG. 1;

FIG. 5 is a diagram showing a difference between an amount of decrease in the area of the contact surface of each of the inner and outer rings (reduction ratio) and an increase in the surface pressure on the contact surface (increase ratio) in the case shown in FIG. 2; .

FIG. 6 is a diagram showing a difference between an amount of decrease in the area of the contact surface of each of the inner and outer rings (reduction ratio) and an amount of increase in the surface pressure on the contact surface (increase ratio) in the case shown in FIG. 3; .

FIG. 7 is a diagram showing a difference between an amount of decrease in the area of the contact surface of each of the inner and outer rings (reduction ratio) and an amount of increase in the surface pressure on the contact surface (increase ratio) in the case shown in FIG. 4; .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Deep groove ball bearing (ball bearing) 2 ... Inner ring 3 ... Outer ring 4 ... Ball 6 ... Outer surface of inner ring (contact surface) 7 ... Inner surface of outer ring (contact surface) 8 ... Groove 9 ... Groove

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor, Nobori, Nobori 5-5-1, Kugenuma Shinmei, Fujisawa-shi, Kanagawa Japan Seiko Co., Ltd. F-term (reference) 3J101 AA02 AA42 AA54 AA62 BA53 BA54 BA55 FA41 FA44 GA53

Claims (3)

[Claims] 1. An inner ring, an outer ring, and a ball rotatably provided between the inner ring and the outer ring, and a contact surface of the inner ring and the outer ring with the ball has an arc-shaped cross section along a circumferential direction. Wherein the arc-shaped groove of the outer race is formed so that its radius of curvature is in the range of more than 53% and not more than 65% of the diameter of the ball. . 2. An inner race, an outer race, and a ball rotatably provided between the inner race and the outer race, and a contact surface of the inner race and the outer race with the ball is arc-shaped in cross section along a circumferential direction. Wherein the arc-shaped groove of the inner ring is formed such that its radius of curvature is in the range of more than 52% and not more than 65% of the diameter of the ball. . 3. An inner ring, an outer ring, and a ball rotatably provided between the inner ring and the outer ring, wherein each of the contact surfaces of the inner ring and the outer ring with the ball has an arc-shaped cross section along a circumferential direction. In the ball bearing having a groove formed as described above, the arc-shaped groove of the outer ring and the arc-shaped groove of the inner ring each have a radius of curvature exceeding 52% and 65% of the diameter of the ball.
A ball bearing characterized by being formed in the following range.