Patent ID: 8013485

Claim:
A motor with an electromagnetic brake comprising: a motor stator; a motor rotor including a shaft and a rotor portion fixed to the shaft, the shaft being formed of a ferromagnetic material and having a load-side end portion and a non-load-side end portion; a first bearing that rotatably supports the shaft at a position in the vicinity of the load-side end portion; a first bearing holder that is fixed to the motor stator and holds the first bearing; a second bearing that rotatably supports the shaft at a position in the vicinity of the non-load-side end portion; a second bearing holder that is ferromagnetic and includes a bearing fitting portion into which the second bearing is fitted; a bearing stopper member that is ferromagnetic and is fixed to the second bearing holder to prevent the second bearing fitted into the second bearing holder from getting out of the bearing fitting portion; an electromagnetic brake including: a brake friction plate fixed to a portion of the shaft that is located between the rotor portion and the second bearing; a brake plate; and an electromagnetic coil disposed on a brake core, the electromagnetic brake bringing the brake plate into contact with the brake friction plate, thereby preventing the shaft from rotating when braking is applied, and keeping the brake plate and the brake friction plate apart from each other by means of an electromagnetic force generated by the electromagnetic coil, thereby allowing the shaft to rotate when braking is not applied; and a magnetic sensor disposed outside an end of the non-load-side end portion of the shaft projecting from the second bearing; wherein the bearing stopper member is of an annular structure having a through-hole through which the shaft passes, and has an inner circumferential surface that faces an outer circumferential surface of the shaft and is located in proximity to the outer circumferential surface of the shaft.