| 摘要 |
PROBLEM TO BE SOLVED: To detect an abnormality with expedition in a power steering gear employed to generate steering assist force inside a vehicular steering gear having a transmission ratio varying means to vary the transmission ratio of the steering transmission system, and change over the steering gear to its manual steering mode. SOLUTION: In dependence upon a transmission ratio set by a transmission ratio setting circuit 40 in accordance with an input signal from a vehicle speed sensor 32 and upon an output from a steering angle sensor 26, a target steering- angle arithmetic circuit 42 sets a target steering angle. If an abnormality detecting circuit 46 decides that the deviation of an actual steering angle detected by an output angle sensor 28 from the target steering angle equals or exceeds a preset value or that an abnormality is caused in a power steering gear for generating steering assist force, this abnormality detecting circuit 46 directs a driving circuit 38 not to output a control signal to a gear ratio varying unit 14 to cancel the transmission ratio varying control. |
