Abstract: The disclosure discloses a novel arched commutator structure of a brush direct current motor, which comprises a round nut or a bolt, a pressing ring, a reinforcing ring, a sleeve, a commutator segment group and a mica ring. The effective part of the arched commutator is the commutator segment group consisting of commutator segments with V-shaped gaps at two ends and mica sheets; and the V-shaped groove of the commutator segment group is clamped by the V-shaped cone part of the pressing ring at one end and the V-shaped cone part of the sleeve at the other end. The advantages are: the deformation of the commutator caused by various acting forces generated in the operation process of the motor can be reduced and even prevented; the economic benefit generated every year cannot be estimated by taking a hundred million as a unit; materials are saved; the production cost is reduced.