CARBON BRUSH AND ROTATING ELECTRICAL MACHINE

摘要

A rotating electrical machine, which is a direct current motor, includes carbon brushes. Each carbon brush contains graphite grains, metal particles, and solid lubricant, which are sintered in a dispersed state. The graphite grains are each formed of granulated substance of raw graphite particles, and the particle diameters of the graphite grains are within a range of 60 to 280 µm. The surface of the granulated substance is coated with amorphous carbon made of carbides of organic binder. A plurality of holes are formed in each carbon brush. The dimension (maximum dimension) of the holes is less than half the average particle diameter of the raw graphite particles.