| 摘要 |
The present invention pertains to a locking and unlocking mechanism, which is equipped with an electromagnet (1) and is used preferably to embody a key and/or shift lock function in motor vehicles. Its basic object is to design such a mechanism such that the generation of noise during the transition from one state into the other is reduced compared with prior-art solutions. To accomplish the object, a pulsating voltage in the form of a direct voltage-rated pulse width signal (PWM voltage) is sent to the electromagnet (1). The effective value of the PWM voltage is increased over at least three voltage pulses from an off-load voltage value to a preset final voltage value at the beginning of a phase of energization and it conversely drops, again over at least three voltage pulses, to the off-load voltage value at the end of the phase of energization, in a time-controlled manner by means of a circuit unit (2) associated with a pulse width modulator (3). |
