Abstract: A manufacturing method for a brush that can reduce contact surface area between a commutator and the brush, thereby reducing frictional noise, is provided. Specifically, a method to manufacture a brush, which provides one surface with contact surfaces that make sliding contact with the commutator, involves a step to mold a molded body and a step to cut the molded body. In the molding process, carbon powder containing copper powder is sintered to form a molded body having a groove on the top surface along the direction of the axis of rotation of the commutator, and curved surface margins in the margins of the top surface in the direction of the axis of rotation. In the cutting step, the central part of the top surface of the molded body is cut by a grinding stone along the cutting direction to form contact surfaces between the margins of the top surface.

Abstract: A manufacturing method for a brush that can reduce contact surface area between a commutator and the brush, thereby reducing frictional noise, is provided. Specifically, a method to manufacture a brush, which provides one surface with contact surfaces that make sliding contact with the commutator, involves a step to mold a molded body and a step to cut the molded body. In the molding process, carbon powder containing copper powder is sintered to form a molded body having a groove on the top surface along the direction of the axis of rotation of the commutator, and curved surface margins in the margins of the top surface in the direction of the axis of rotation. In the cutting step, the central part of the top surface of the molded body is cut by a grinding stone along the cutting direction to form contact surfaces between the margins of the top surface.