Carbon Product

• US 20150284251A1
• Filed: 04/02/2015
• Published: 10/08/2015
• Est. Priority Date: 04/02/2014
• Status: Abandoned Application

• Current Assignee: Johnson Electric International AG (Johnson Electric Holdings Limited)
• Original Assignee: Johnson Electric SA (Johnson Electric Holdings Limited)
• Inventors: WU, Yiu Chung, ZHENG, Jing Chao, LAW, Chi Man, WANG, Xiu Xian
• Application Number:
  US14/677,306
• Publication Number:
  US 20150284251A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C01B 32/00 Carbon; Compounds thereof C01B21/00, C01B23/00 take precedence; percarbonates C01B15/10; carbon black C09C1/48
• CPC Class Codes: C01B 32/05 Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
• CPC Class Codes: C01P 2006/10 Solid density
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C04B 2235/422 Carbon
• CPC Class Codes: C04B 2235/425 Graphite
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 35/528 obtained from carbonaceous particles with or without other non-organic components
• CPC Class Codes: C04B 35/6267 Pyrolysis, carbonisation or auto-combustion reactions
• CPC Class Codes: C09C 1/44 Carbon
• CPC Class Codes: C09C 1/46 Graphite C09C1/0015 takes precedence
• CPC Class Codes: H01R 39/045 the commutators being made of carbon
• CPC Class Codes: H01R 43/06 Manufacture of commutators

Abstract

A carbon product is made of mesocarbon microbeads and graphite. Preferably, the weight percent of mesocarbon microbeads is 50-99% and the weight percent of graphite is 1-50%. Preferably, when the graphite is carbon-graphite, the carbon product has a density in the range of 1.6-1.8 g/cm³ and a resistivity in the range of 2000-8000 μΩ·cm. Preferably, when the graphite is electro-graphite, the carbon product has a density in the range of 1.85-1.95 g/cm³ and a resistivity in the range of 500-2000 μΩ·cm. The carbon product may be a carbon brush, a carbon bearing, a carbon seal or a brush contact member for a commutator of an electric motor.

Claims

1. A commutator for an electric motor, comprising:

a base made of insulation material;

an electrically conductive member fixed to the base, the electrically conductive member comprising a plurality of bars each with a tang for connection of a lead wire of the motor; and

a contact member forming a brush contact surface, the contact member comprising a plurality of segments each electrically connected with a corresponding bar, the contact member comprising mesocarbon microbeads and graphite.

2. The commutator of claim 1, wherein in the contact member the weight percent of mesocarbon microbeads is 1-99% and the weight percent of graphite is 1-99%.

3. The commutator of claim 1, wherein in the contact member the weight percent of mesocarbon microbeads is 50-99% and the weight percent of graphite is 1-50%.

4. The commutator of claim 1, wherein in the contact member the weight percent of mesocarbon microbeads is 70-80% and the weight percent of graphite is 20-30%.

5. The commutator of claim 1, wherein the graphite is natural graphite.

6. The commutator of claim 1, wherein the graphite is artificial graphite.

7. The commutator of claim 1, wherein the diameter of the mesocarbon microbeads is less than 150 μ

m.

8. A method of making a carbon product, comprising:

mixing mesocarbon microbeads and electrographite;

iso-static pressing the mixed mesocarbon microbeads and electrographite to form a blank;

sintering the blank;

graphitizing the sintered blank; and

machining the graphitized blank to form a predetermined shape of the carbon product.

9. The method of claim 8, further comprising sieving the mesocarbon microbeads to choose the mesocarbon microbeads with size less than predetermined size before the mixing step.

10. The method of claim 8, wherein the step of sintering the blank comprises sintering the blank such that the sintered blank has a density in the range of 1.85-1.95 g/cm³ and a resistivity in the range of 500-2000 μ

Ω

·

cm.

11. A method of making a carbon product, comprising the steps of:

mixing together powdered mesocarbon microbeads and powdered carbon-graphite;

kneading the mixed mesocarbon microbead and graphite powder;

compressing the mixed powder to form a blank;

sintering the blank; and

machining the sintered blank to form the carbon product.

12. The method of claim 11, wherein the method further comprises a step of sieving the powder after the kneading step and before the compressing step.

13. The method of claim 12, wherein the method further comprises a step of mixing the powder after the sieving step and before the compressing step.

14. The method of claim 11, wherein the step of sintering the blank comprises sintering the blank such that the sintered blank has a density in the range of 1.6-1.8 g/cm³ and a resistivity in the range of 2000-8000 μ

Ω

·

cm.

15. A carbon product made of mesocarbon microbeads and graphite, wherein the weight percent of mesocarbon microbeads is 50-99% and the weight percent of graphite is 1-50%.

16. The carbon product of claim 15, wherein the weight percent of mesocarbon microbeads is 70-80% and the weight percent of graphite is 20-30%.

17. The carbon product of claim 15, wherein the carbon product is a product selected from the group consisting of:

a carbon bearing;

a carbon brush;

a carbon seal; and

a brush contact surface of a commutator.

18. The carbon product of claim 15, wherein the carbon product has a density in the range of 1.6-1.8 g/cm³ and a resistivity in the range of 2000-8000 μ

Ω

·

cm.

19. The carbon product of claim 15, wherein the carbon product has a density in the range of 1.85-1.95 g/cm³ and a resistivity in the range of 500-2000 μ

Ω

·

cm.