Claims
- 1. A linear motion device comprising:an outer member; an inner member facing said outer member via a gap; a multiplicity of balls disposed between said outer member and said inner member; and a plurality of spacers; said outer member being linearly moveable relative to said inner member; wherein each spacer is disposed between two adjacent balls and has two concave surfaces facing respectively to said two balls; and each concave surface of at least one spacer includes a frusto-conical surface portion which, as viewed in an axial direction of the spacer, makes line contact with the adjacent ball.
- 2. A linear motion device according to claim 1,wherein said at least one spacer is an integrally formed member.
- 3. A linear motion device according to claim 2,wherein said at least one spacer is made of plastic.
- 4. A linear motion device according to claim 2,wherein said at least one spacer is made of metallic material.
- 5. A linear motion device according to claim 2,wherein a sectional shape of each concave surface of said at least one spacer includes a central portion substantially perpendicular to a line joining respective centers of the adjacent balls, and a pair of inclined portions extending from opposite ends of the central portion to an axial end portion of the spacer.
- 6. A linear motion device according to claim 1, wherein said frusto-conical surface portion is part of a conical surface of said at least one spacer.
- 7. A linear motion device comprising:an outer member; an inner member facing said outer member via a gap; a multiplicity of balls disposed between said outer member and said inner member; and a plurality of spacers; said outer member being linearly movable relative to said inner member; wherein each spacer is disposed between two adjacent balls and has two concave surfaces facing respectively to said two balls; and a shape of each concave surface of at least one spacer is such that, as viewed in an axial direction of the spacer, the concave surface makes substantially circular line contact with the adjacent ball.
- 8. A linear motion device according to claim 7,wherein said at least one spacer is an integrally formed member.
- 9. A linear motion device according to claim 8,wherein said at least one spacer is made of plastic.
- 10. A linear motion device according to claim 8,wherein said at least one spacer is made of metallic material.
Priority Claims (3)
Number |
Date |
Country |
Kind |
10-167813 |
Jun 1998 |
JP |
|
10-239458 |
Aug 1998 |
JP |
|
11-026544 |
Feb 1999 |
JP |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 09/317,978 filed May 25, 1999, now U.S. Pat. No. 6,347,558.
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Entry |
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Continuations (1)
|
Number |
Date |
Country |
Parent |
09/317978 |
May 1999 |
US |
Child |
10/038660 |
|
US |