The present disclosure teaches an electric machine including a housing for receiving a rotor unit and a connecting unit. The rotor unit may rotate around an axis of rotation and have a rotor shaft and a first sliding surface. The connecting unit may include a carrier, a contact part, and a spring part. The carrier part may be made of an electrically conductive material and at least partially surround the rotor shaft and is firmly connected to the housing. The contact part may be made of an electrically conductive material, including a second sliding surface. The spring part may be made of an electrically conductive material, at least partially surrounding the rotor shaft. The spring part may be firmly connected to the carrier part and the contact part and press the contact part against the first sliding surface so the sliding surfaces form the electrically conductive sliding contact.

A brush assembly has a brush, a brush cage, and a spring. The spring is a constant force spring having two coil portions and a connecting portion. The connecting portion the brush are together received in the brush cage. The brush has a contact end arranged to make sliding contact with a commutator and a second end remote from the contact end against which the spring applies its force, to urge the brush out of the brush cage. A hook is formed at each of two opposite sides of the brush cage, at a first end portion of the brush cage adjacent the contact end of the brush. The coil portions respectively engage the hooks. The hooks extend at different angles to a corresponding outer surface of the brush cage.

Devices and methods of use for brush holder assemblies are disclosed. Brush holder assemblies including a mounting block and a brush holder are disclosed. Also illustrated is a brush holder assembly including a first portion in sliding engagement with a second portion. In some embodiments the brush holder includes a channel, such that at least a portion of the mounting block is disposed within the channel of the brush holder.

A brush holder device includes: a pair of brush holders placed on a base to slidably hold brushes, respectively, in directions orthogonal to an outer circumferential surface of a commutator; first and second supporting columns are erected next to each other in a region between the pair of brush holders; and first and second torsion springs including wound portions fit around the respective supporting columns, first ends extend from the wound portions serving as working ends to abut against the respective brushes, and second ends extend from the wound portions serving as reaction ends to be restrained by outer circumferential surfaces of the supporting columns on the respective opposite sides.

A carbon brush holder is provided, which includes an insulating base, a metal brush frame, and two carbon brushes, wherein the insulating base includes a first base and two second bases correspondingly engaging with two matching portions of the first base respectively; the first base has a first slot having a straight section and two winding sections respectively connected to two ends of the straight section and each of the second bases has a second slot, and a protrusion is formed on a slot wall thereon. The metal brush frame includes a main frame and two branch frames respectively connected to two ends of the main frame, wherein the main frame is embedded in the first slot; the two branch frames are embedded in the two second slots, and are connected to two carbon brushes respectively, to thereby provide an improved contact between the two carbon brushes and a slip ring assembly.

A brush holder apparatus for receiving a brush, includes a support member, and at least one box member affixed to the support member. The box member includes a slot extending through a side of the box member. At least one cam member is operably connected to the support member. The cam member includes a rounded surface partially extending through the slot. The rounded surface is configured to directly contact the brush while the cam member retains the brush. The cam member is configured to move within the slot, and the cam member is configured to retain the brush against an inner surface of the box member. The at least one cam member is configured for manual manipulation (e.g., by hand) so that the brush can be removed from the at least one box member without the use of any tools.

A motor assembly includes: a motor housing including: at least one brush receptacle having top and bottom ends; a locking element extending from the top end toward the bottom end; and a housing spring member; at least one brush holder apparatus including: a brush holder housing sized to be received within the brush receptacle, including: an upper surface and a lower surface; a receiving aperture; and an open end; a brush spring enclosed by the brush holder housing; and a brush located inside the brush holder housing; wherein the brush holder apparatus is inserted inside the brush receptacle; and wherein the housing spring member urges the brush holder apparatus toward the top end such that the locking element is received inside the receiving aperture.

A carbon brush holder is provided, which includes an insulating base, a metal brush frame, and two carbon brushes, wherein the insulating base includes a first base and two second bases correspondingly engaging with two matching portions of the first base respectively; the first base has a first slot having a straight section and two winding sections respectively connected to two ends of the straight section and each of the second bases has a second slot, and a protrusion is formed on a slot wall thereon. The metal brush frame includes a main frame and two branch frames respectively connected to two ends of the main frame, wherein the main frame is embedded in the first slot; the two branch frames are embedded in the two second slots, and are connected to two carbon brushes respectively, to thereby provide an improved contact between the two carbon brushes and a slip ring assembly.

A brush holder for an electric motor includes a brush magazine forming a receiving space with a wall surface. A carbon brush having an end face and a side face is arranged in the receiving space. The brush holder also includes a spring, which is in contact with the end face and is configured to press the carbon brush in an extension direction of the receiving space. The brush holder also includes a pressing mechanism arranged on a pivot arm and configured to contact the side face and press the carbon brush by the force of the spring in a pressing direction against the wall surface. The pivot arm has a pivot shaft, to which an inner end of the spring is fastened. The pressing mechanism has a rolling surface configured to roll over the side face of the carbon brush when the carbon brush slides in the extension direction.

A monitoring apparatus configured for monitoring a carbon brush of a brush holder assembly of an electrical machine. The monitoring apparatus may include a flexible sensor and a signal processing circuit for processing a signal received from the flexible sensor. The flexible sensor may have an electrical resistance that varies based on a radius of curvature of the flexible sensor, wherein the radius of curvature of the flexible sensor may be associated with a deflection of a spring providing a force to engage the carbon brush with a rotating component of the electrical machine. The signal processing circuit may be coupled to the sensor and may be configured to determine a measure of a wear state of the carbon brush using information about the variable resistance of the flexible sensor.