Carbon brush with raw graphite particles

1. A carbon brush comprising graphite grains and metal particles, the graphite grains and metal particles being sintered in a dispersed state,

wherein the graphite grains are each formed of granulated substance of raw graphite particles, wherein a surface of each of the raw graphite particles in each graphite grain is in directly close contact with a surface of each of the adjacent raw graphite particles,

wherein a number of the raw graphite particles in each graphite grain are collectively coated with amorphous carbon, wherein such amorphous carbon exists only on the surface of the graphite grains,

wherein the particle diameter of each graphite grain is within a range of 60 to 280 μm, and

wherein the carbon brush has a plurality of holes, dimensions of the holes being distributed within a range of 4 to 14 μm.

2. The carbon brush according to claim 1 , wherein an average of the dimensions of the holes is 9 μm.

3. A carbon brush comprising graphite grains and metal particles, the graphite grains and metal particles being sintered in a dispersed state,

wherein the graphite, grains are each formed of granulated substance of raw graphite particles, wherein a surface of each of the raw graphite particles in each graphite grain is in directly close contact with a surface of each of the adjacent raw graphite particles,

wherein a number of the raw graphite particles in each graphite grain are collectively coated with amorphous carbon, wherein such amorphous carbon exists only on the surface of the graphite grains,

wherein the particle diameter of each graphite grain is less than or equal to ten times the average particle diameter of the raw graphite particles, and

wherein the carbon brush has a plurality of holes, dimensions of the holes being distributed within a range of 4 to 14 μm.

4. The carbon brush according to claim 3 , wherein an average of the dimensions of the holes is 9 μm.

5. A carbon brush comprising graphite grains and metal particles, the graphite grains and metal particles being sintered in a dispersed state,

wherein the graphite grains are each formed of granulated substance of raw graphite particles, wherein a surface of each of the raw graphite particles in each graphite grain is in directly close contact with a surface of each of the adjacent raw graphite particles,

wherein a number of the raw graphite particles in each graphite grain are collectively coated with amorphous carbon, wherein such amorphous carbon exists only on the surface of the graphite grains,

wherein the average particle diameter of the graphite grain is less than or equal to five times the average particle diameter of the raw graphite particles, and

wherein the carbon brush has a plurality of holes, dimensions of the holes being distributed within a range of 4 to 14 μm.

6. The carbon brush according to claim 5 , wherein an average of the dimensions of the holes is 9 μm.

7. A carbon brush comprising graphite grains and metal particles, the graphite grains and metal particles being sintered in a dispersed state,

wherein the graphite grains are each formed of granulated substance in which raw graphite particles are bound together, wherein a surface of each of the raw graphite particles in each graphite grain is in directly close contact with a surface of each of the adjacent raw graphite particles,

wherein a number of the raw graphite particles in each graphite grain are collectively coated with amorphous carbon, wherein such amorphous carbon exists only on the surface of the graphite grains,

wherein the carbon brush has holes, dimensions of the holes being distributed within a range of 4 to 14 μm.

8. The carbon brush according to claim 7 , wherein an average of the dimensions of the holes is 9 μm.

9. A rotating electrical machine comprising a carbon brush comprising graphite grains and metal particles, the graphite grains and metal particles being sintered in a dispersed state,

wherein the graphite grains are each formed of granulated substance of raw graphite particles, wherein a surface of each of the raw graphite particles in each graphite grain is in directly close contact with a surface of each of the adjacent raw graphite particles,

wherein a number of the raw graphite particles in each graphite grain are collectively coated with amorphous carbon, wherein such amorphous carbon exists only on the surface of the graphite grains,

wherein the particle diameter of each graphite grain is within a range of 60 to 280 μm and

wherein the carbon brush has a plurality of holes, dimensions of the holes being distributed within a range of 4 to 14 μm.

10. A rotating electrical machine comprising a carbon brush comprising graphite grains and metal particles, the graphite grains and metal particles being sintered in a dispersed state,

wherein the graphite grains are each formed of granulated substance of raw graphite particles, wherein a surface of each of the raw graphite particles in each graphite is in directly close contact with a surface of each of the adjacent raw graphite particles,

wherein a number of the raw graphite particles in each graphite grain are collectively coated with amorphous carbon, wherein such amorphous carbon exists only on the surface of the graphite grains,

wherein the particle diameter of each graphite grain is less than or equal to ten times the average particle diameter of the raw graphite particles, and

wherein the carbon brush has a plurality of holes, dimensions of the holes being distributed within a range of 4 to 14 μm.

11. The rotating electrical machine according to claim 10 , wherein an average of the dimensions of the holes is 9 μm.

12. A rotating electrical machine comprising a carbon brush comprising graphite grains and metal particles, the graphite grains and metal particles being sintered in a dispersed state,

wherein the graphite grains are each formed of granulated substance of raw graphite particles, wherein a surface of each of the raw graphite particles in each graphite is in directly close contact with a surface of each of the adjacent raw graphite particles,

wherein a number of the raw graphite particles in each graphite grain are collectively coated with amorphous carbon, wherein such amorphous carbon exists only on the surface of the graphite grains,

wherein the average particle diameter of the graphite grain is less than or equal to five times the average particle diameter of the raw graphite particles, and

wherein the carbon brush has a plurality of holes, dimensions of the holes being distributed within a range of 4 to 14 μm.

13. The rotating electrical machines according to claim 12 , wherein an average of the dimensions of the holes is 9 μm.

14. A rotating electrical machine comprising a carbon brush comprising graphite grains and metal particles, the graphite grains and metal particles being sintered in a dispersed state,

wherein the graphite grains are each formed of granulated substance in which raw graphite particles are bound together, wherein a surface of each of the raw graphite particles in each graphite grain is in directly close contact with the adjacent raw graphite particles,

wherein a number of the raw graphite particles in each graphite grain are collectively coated with amorphous carbon, wherein such amorphous carbon exists only on the surface of the graphite grains, and

wherein the carbon brush has a plurality of holes, dimensions of the holes being distributed within a range of 4 to 14 μm.

15. The rotating electrical machine according to claim 14 , wherein an average of the dimensions of the holes is 9 μm.