| 摘要 |
PURPOSE: To provide a highly reliable steering device for a vehicle which makes use of an electric motor for controlling steering of, for example, rear wheels in the case of a four-wheel steering device. CONSTITUTION: A target steering angle for rear wheels is calculated based on a signal detected by a vehicle and steering is controlled by an electric motor 16. Either of a clockwise and a counterclockwise turn direction signals R, L for the motor 16 and also a PWM signal expressing motor currentare output from a controller 30 in accordance with the target steering direction and are given as directives to an FET drive circuit 31. The motor 16 is controlled by a bridge circuit 32 composed of switching elements FET1 to FET4 and these switching elements cause, based on gate signals G1 to G4 coming from the FET drive circuit 31, motor driving current to flow in such a way as indicated by the arrow for example. When a clockwise turn, for example, is directed, the direction signal R is set at an H-level and the signal L is set at an L-level, and a logic circuit incorporated in the FET drive circuit 31 causes one of the switching elements located on one and the same arm of the bridge circuit 32 not to be turned on simultaneously with the other. |
