BRAKE ACTUATOR FOR A BRAKE OF A RAIL VEHICLE, BRAKE SYSTEM COMPRISING THE BRAKE ACTUATOR, RAIL VEHICLE, AND METHOD FOR ESTIMATING A BRAKE FORCE OF THE BRAKE ACTUATOR

A brake actuator (3) comprises: a housing (6), a rotating motor (7), a rotating body (8), a spindle (9), a rotational sensor (10), and a motor brake (11). The rotating body (8) is supported in the housing (6), a rotation of the rotating body (8) with respect to the spindle (9) generates a motion of the spindle (9), wherein the brake actuator (3) generates a brake force (F) by the motion of the spindle (9), the rotating motor (7) generates a motor torque for the rotation of the rotating body (8), the rotational sensor (10) detects an angular position of the rotating body (8), and the motor brake (11) locks the rotation of the rotating body (8) with respect to the housing (6) such that, in a locked state, the rotating body (8) can freely rotate around the rotational axis (4) about a predefined angle (α).