Patent ID: 7294166

Claim:
A metal-graphite brush comprising a copper-graphite brush body into which a metal sulfide solid lubricant is mixed and a lead embedded in the copper-graphite brush body characterized in that a concentration of the metal sulfide solid lubricant in the copper-graphite brush body is made different between in a neighborhood of the lead in the copper-graphite brush body and a portion of the copper-graphite brush body with which a commutator of a rotational electric armature is to be in contact and a concentration of the metal sulfide solid lubricant in the neighborhood of the lead in the copper-graphite brush body is lower than a concentration of the metal sulfide solid lubricant in the portion of the copper-graphite brush body in contact with the commutator, wherein the concentration of the metal sulfide solid lubricant in the neighborhood of the lead in the copper-graphite brush body is less than 1 wt. %.