Sintered bearing and method of manufacturing same

Patent metadata

Field	Value
Publication number	US-9989092-B2
Application number	US-201414899896-A
Country	US
Kind code	B2
Filing date	Jun 25, 2014
Priority date	Jul 22, 2013
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A sintered bearing includes a sintered metal formed by using a metal powder mixture containing copper powder and iron powder. The metal powder mixture contains 80 wt % or more of particles having an average particle diameter of less than 45 μm. The copper powder contains electrolytic copper powder. The electrolytic copper powder contains 40 number % or more of particles having a circularity of 0.64 or more.

First claim

The invention claimed is:

1. A sintered bearing, comprising a sintered metal formed by using a metal powder mixture containing copper powder and iron powder,
the metal powder mixture containing 80 wt % or more of particles having an average particle diameter of less than 45 μm,
the copper powder containing electrolytic copper powder containing 40 number % or more of particles having a circularity of 0.64 or more.

2. The sintered bearing according to claim 1 , wherein the copper powder contains 85 wt % or more of particles having an average particle diameter of less than 45 μm.

3. The sintered bearing according to claim 1 , wherein the copper powder contains less than 10 wt % of particles having an average particle diameter of less than 10 μm.

4. The sintered bearing according to claim 1 , wherein the electrolytic copper powder has an apparent density of from 1.4 g/cm 3 to 1.7 g/cm 3 .

5. The sintered bearing according to claim 1 , wherein the metal powder mixture contains 50 wt % to 60 wt % of the electrolytic copper powder.

6. The sintered bearing according to claim 1 , wherein the iron powder contains 80 wt % or more of particles having an average particle diameter of less than 45 μm.

7. The sintered bearing according to claim 1 , wherein the iron powder comprises reduced iron powder.

8. The sintered bearing according to claim 1 , comprising a sintered metal containing 38 wt % to 42 wt % of iron and 1 wt % to 3 wt % of tin, with the balance being copper and unavoidable impurities.

9. A fluid dynamic bearing device, comprising:
the sintered bearing of claim 1 ;
a shaft member inserted into an inner periphery of the sintered bearing; and
a lubricating oil filled into a radial bearing gap formed between an inner peripheral surface of the sintered bearing and an outer peripheral surface of the shaft member.

10. A motor, comprising:
the fluid dynamic bearing device of claim 9 ;
a stator coil; and
a rotor magnet.

11. A method of manufacturing a sintered bearing, comprising:
subjecting a metal powder mixture containing copper powder and iron powder to compression molding to form a compact; and
sintering the compact at a predetermined sintering temperature,
the metal powder mixture containing 80 wt % or more of particles having an average particle diameter of less than 45 μm,
the copper powder containing electrolytic copper powder containing 40 number % or more of particles having a circularity of 0.64 or more.

12. The method of manufacturing the sintered bearing according to claim 11 , wherein the copper powder contains 85 wt % or more of particles having an average particle diameter of less than 45 μm.

13. The method of manufacturing the sintered bearing according to claim 11 , wherein the copper powder contains less than 10 wt % of particles having an average particle diameter of less than 10 μm.

14. The method of manufacturing the sintered bearing according to claim 11 , wherein the electrolytic copper powder has an apparent density of from 1.4 g/cm 3 to 1.7 g/cm 3 .

15. The method of manufacturing the sintered bearing according to claim 11 , wherein the metal powder mixture contains 50 wt % to 60 wt % of the electrolytic copper powder.

16. The method of manufacturing the sintered bearing according to claim 11 , wherein the iron powder contains 80 wt % or more of particles having an average particle diameter of less than 45 μm.

17. The method of manufacturing the sintered bearing according to claim 11 , wherein the iron powder comprises reduced iron powder.

18. The method of manufacturing the sintered bearing according to claim 11 , comprising a sintered metal containing 38 wt % to 42 wt % of iron and 1 wt % to 3 wt % of tin, with the balance being copper and unavoidable impurities.

Assignees

• Ntn Toyo Bearing Co Ltd

Inventors

• Kurimura Tetsuya
• Ito Fuyuki
• Komatsubara Shinji
• Uchiyama Tadahiro

Classifications

• B22F1/052

  characterised by a mixture of particles of different sizes or by the particle size distribution · CPC title

• B22F1/09

  Mixtures of metallic powders · CPC title

• F16C17/08

  for supporting the end face of a shaft or other member, e.g. footstep bearings · CPC title

• B22F5/00

  Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product · CPC title

• H02K7/08

  Structural association with bearings · CPC title