Ball bearing

• US 20020118900A1
• Filed: 10/16/2001
• Published: 08/29/2002
• Est. Priority Date: 10/16/2000
• Status: Active Grant

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Miyagawa, Takayuki, Ishiwada, Hiroshi, Aoki, Mamoru, Aramaki, Hirotoshi, Takamizawa, Toru
• Granted Patent: US 6,474,872 B2
• Time in Patent Office: Days
• US Class Current: 384/516
• CPC Class Codes: F16C 19/06 with a single row or balls
• CPC Class Codes: F16C 19/54 Systems consisting of a plurality of bearings with rolling friction spindle bearings F16C35/08
• CPC Class Codes: F16C 2240/76 Osculation, i.e. relation between radii of balls and raceway groove
• CPC Class Codes: F16C 2370/12 Hard disk drives or the like
• CPC Class Codes: F16C 33/585 of raceways, e.g. ribs to guide the rollers

Abstract

In the ball bearing, the ratio of the radius of curvature of an inner race raceway 4 to the outside diameter of balls 8, 8 is set in the range of 0.51 to 0.54. Also, the ratio of the radius of curvature of an outer race raceway 6 to the outside diameter of balls 8, 8 is set in the range of 0.54 to 0.56. Further, an interior geometric clearance c is set at 13 μm or less. Thanks to these specifications, the balls 8, 8 can be prevented from running up onto the edge of the outer race raceway 6.

Claims

1. A ball bearing, comprising:

an inner race including on the outer peripheral surface thereof an inner race raceway having an arc-shaped section;

an outer race including on the inner peripheral surface thereof an outer race raceway having an arc-shaped section;

a plurality of balls rollably interposed between said inner race raceway and said outer race raceway; and

,

a retainer for rotatably holding said balls;

wherein the ratio r_i/D₈ of the radius of curvature r_i of said inner race raceway to the outside diameter D₈ of said balls is set in the range from 0.51 to 0.54,

the ratio r_e/D₈ of the radius of curvature r_e of said outer race raceway to the outside diameter D₈ of said balls is set in the range from 0.54 to 0.56, and

an interior geometric clearance c is set at 13 μ

m or less, said interior geometric clearance c being a value satisfying an equation of;

c=D₆−

D₄−

2D₈, where D₄ is the diameter of the inner race raceway, D₈ is the outside diameter of the balls, and D₆ is the diameter of the outer race raceway.

2. The ball bearing according to claim 1, wherein the inside diameter R₅ of the inner race is 2.6 mm or less, and the outside diameter D₈ of said balls is 2 mm or less.

3. A ball bearing, comprising:

an inner race including on the outer peripheral surface thereof an inner race raceway having an arc-shaped section;

an outer race including on the inner peripheral surface thereof an outer race raceway having an arc-shaped section;

a plurality of balls rollably interposed between said inner race raceway and said outer race raceway; and

,

a retainer for rotatably holding said balls;

wherein the ratio r_i/D₈ of the radius of curvature r_i of said inner race raceway to the outside diameter D₈ of said balls is set at 0.51 or more,

the ratio r_e/D₈ of the radius of curvature r_e of said outer race raceway to the outside diameter D₈ of said balls is set at 0.54 or more,

said ratios r_i/D₈ and r_e/D₈ are respectively set in the range that can satisfy an equation of;

0.647×

(r_e/D₈)^0.385≦

(r_i/D₈)≦

0.662×

(r_e/D₈)^0.385,

where r_i is the radius of curvature of said inner race raceway, r_e is the radius of curvature of said outer race raceway, and D₈ is the outside diameter of the balls, and

an interior geometric clearance c is set in the range that can satisfy the relationship 0.003 <

(c/D₈)<

0.01, said interior geometric clearance c being a value satisfying an equation of;

c=D₆−

D₄−

2D₈,

where D₆ is the diameter of the outer race raceway, D₄ is the diameter of the inner race raceway, and D₈ is the outside diameter of the balls.