Patent ID: 6157108
Filing Date: 2000-12-05
Classification: H01R

Abstract:
A commutator (10, 110, 210) having an axis of rotation (14, 114, 214) comprising a plurality of copper segments (26, 126, 226) embedded in a plastic element (12, 112, 212), each of the copper segments forming an armature retainer (28, 128, 228); and at least one reinforcing ring (16, 116, 216) arranged coaxially to the axis of rotation (14, 114, 214) of the commutator being received within a corresponding receptacle (15, 115, 215) of said copper segments, said at least one reinforcing ring comprising a single metal ring (18, 118, 218) and an insulating ring (20, 120, 220) assembled with the metal ring (18, 118, 218), wherein the insulating ring (20, 120, 220) is step-like formed and comprises:a support piece (22, 122, 222); anda flange piece (24, 124, 224) attached to the support piece radially outward and axially displaced, both the support piece and the flange piece being formed from a single unit, and wherein the metal ring (18, 118, 218) is fitted into the step-like insulating ring (20, 120, 220) so that a portion of the radial outer surface of the metal ring (18, 118, 218) is adjacent to the radial inner surface of the flange piece (24, 124, 224), and a flat face of the metal ring (18, 118, 218) abuts a flat face of the support piece (22, 112, 222);whereby the reinforcing ring (16, 116, 216) forms a redundant reinforcing system so that the metal ring (18, 118, 218) and the support piece (22, 122, 222) are spatially separated and independent of each other, each bearing along its respective axial position the load from the armature retainers (28, 128, 228) of the copper segments which results from the effects of the centrifugal force of the copper segments (26, 126, 226); andwherein a first part (a) of the radial outer surface of the armature retainers (28, 128, 228) presses against the metal ring (18, 188, 218) in the radial direction across a high temperature, compression-resistant intermediate layer (30, 130, 230) of the plastic element (12, 112, 212), whereas a second part (b) of the radial outer surface of the of the armature retainers arranged in the axial direction adjacent to said first part (a) presses against said support piece (22, 122, 222), said support piece immediately adjacent to the metal ring having a smaller inside diameter than the metal ring, there being no part of the plastic element between the radially inner surface of the support piece and the adjacent portion of the armature retainers, and further there being exclusively plastic material of the plastic element present between the radially inner surface of the metal ring and the adjacent portion of the armature retainers.