A method for determining the operating temperature of a direct current motor, in particular for actuating an electric parking brake, and for reversing the polarity of the motor current

摘要

In order, in the case of an electromotive parking brake (11) is always the same actuators moment (mmax) to be activated, the cut-off value (imax) of the motor current (i) as a function of the operating temperature (t) of the dc motor (13) varies.In order in the case of the determination of the operating temperature (t) of a direct current motor (13) via a close to its rotor (12) arranged sensor does not require any additional lines for the actuators are to be, the commutator (25) for the rotor coils (24) a thermistor (26) is connected in series with a diode (27), connected in parallel and during rotor at a standstill state of the thermistor current as a current difference (di) of varying measuring current - polarities (i +, i -) is determined.In order, for a polarity inversion of the motor - and - the measuring currents (i, i) by means of the commutator (25) of a direct current motor (13) to require no transistor bridge, is used a two-pole switching relays (28) as a reversing circuit (20), which only switches in the de-energized state, in that a in series with it a switching transistor (31) at the latest simultaneously with the relay - excitation coil (29) is controlled.