PURPOSE: To stop an electric motor when steering power does not need to be supplemented, by driving the motor only for a prescribed period of time.
CONSTITUTION: When a transmission is not in the low and reverse positions, the first OR circuit 22 of a controller 17 does not supply an output signal S5 because a low signal S1 and a reverse signal S2 are not applied to the circuit 22. For that reason, an AND circuit 24 does not supply an output signal S6 regardless of the send-out and non-send-out of a steering signal S3 from a steering sensor 19 which detects the turning of a steering wheel 5 and a steering operation hold-on sensor 20 does not sends out a steering operation hold-on signal S4, so that the second OR circuit 23 does not supply a driving signal S7. As a result, an electric motor 2 is not driven, so that an oil pump 3 is not moved and no pressurized oil is supplied. Therefore, a power steering gear 1 is not operated.
KUNIKI YOSHIHIRO
ABE MASAO
MAEDA NAOYUKI
TOKAI TRW & CO