| 摘要 |
<p>A pump-drive device of a power-assisted vehicle steering system, comprising a motor (8) operative to drive a steering pressure pump (6), a first sensor (14) for detecting vehicle speed and producing an output signal (Sv) representative of the detected vehicle speed, a second sensor (15) for detecting the motor output speed and producing an output signal (Sn) representative of the detected motor output speed, a current control circuit (12) responsive to the output signals (Sv,Sn) from the first and second sensors (14,15), a main current supply line (27) connected between a power source (9) and the motor (8) through the current control circuit (12), a bypass current supply line (28) bypassing the current control circuit (12) between the power source (9) and the motor (8), the current control circuit (12) being operative to produce an output signal (Sd) to vary the current to be passed through the main current supply line (27) on the basis of the output signals (Sv,Sn) from the first and second sensors (14,15), a detecting unit (30) responsive to a predetermined operative condition of the steering system and operative to produce an output signal when the steering system is in the predetermined operative condition, and a line shifting switch unit (24) to provide electrical connection selectively between the power source (9) and the motor (8) selectively through the main and bypass current supply lines (27,28) in the absence and presence, respectively, of the output signal from the detecting unit (30).</p> |
