Patent ID: 7649297
Filing Date: 2010-01-19
Classification: H01R,H02K,Y10T

Abstract:
1. A commutator comprising: a plurality of segments arranged in a circumferential direction, each segment having a slidable contact surface that a feeder brush slidably contacts; a substantially disk-like short-circuit member assembly having a first end surface and a second end surface that face in opposite directions, the short-circuit member assembly including a group of short-circuit pieces, the group including a plurality of short-circuit pieces that are arranged in a circumferential direction to form a disk-like shape as a whole, each short-circuit piece having an outer terminal, an inner terminal arranged radially inward from the outer terminal and circumferentially offset from the outer terminal at a predetermined offset angle, and a connecting portion connecting the inner terminal to the outer terminal, each of the segments being connected to at least one of the outer terminal and the inner terminal so that each pair of the segments that are to have equal potentials are short-circuited; a holding portion that covers the segments and at least a portion of the short-circuit member assembly to hold the segments and the short-circuit member assembly, the holding portion being formed of an insulating resin material; and a plurality of spacing members each having an insulated support portion and a plurality of insulated spacing projections formed integrally with the support portion, each support portion extending along the first end surface or the second end surface in a radial direction of the short-circuit member assembly, the spacing projections being arranged in the direction in which the corresponding support portions extend in such a manner that the spacing projections are each provided between the corresponding circumferentially adjacent pair of the connecting portions; wherein, if the offset angle is represented by θ, the number of the spacing members is at least (360°/θ), the spacing members being spaced at equal angular intervals in the circumferential direction of the short-circuit member assembly, wherein the length of each support portion in the radial direction of the short-circuit member assembly is equal to the radial width of an annular range corresponding to the connecting portions, and wherein each support portion includes the spacing projections located at both sides of the corresponding connecting portion extending across the support portion.