Electric motor arrangement adapted for use in an actuator and an actuator including the motor arrangement

Abstract

This invention relates to a linear type actuator unit, said actuator unit (), including an electric motor () driving a linear actuator () of, said motor () having a casing (), a stator () fixed to the casing, a rotor () fixed to a rotary part (), preferably a rotary motor shaft (), wherein said rotary part () is arranged to be operatively connected to a reduction gear () which drives the mechanical output of the actuator (), a separate magnetic brake unit (), said magnetic brake () including a rotating brake member () connected to the motor shaft (), directly or indirectly, and a plurality of fixed brake members (), wherein said magnetic brake () is arranged to produce a torque that will strive to position a rotary member () with said rotating brake member () into one or more specific angular positions in relation to the fixed brake members (), and wherein said rotating brake member () is in the form of a separate annulus () attached to said rotary member () arranged to brake the motor at low rotational speeds and in that the actuator unit () is arranged with a circuitry () including a short circuiting arrangement () arranged to enable braking of the motor () at rotational speeds above low rotational speeds.