| 摘要 |
PROBLEM TO BE SOLVED: To provide a steering device for a vehicle capable of improving steering performance of the vehicle.SOLUTION: In a steering device for a vehicle, a transmission ratio variable mechanism 30, that varies a transmission ratio between a first shaft 4a and a second shaft 4b by adding the rotation of a rotary shaft of a motor to the rotation of the first shaft 4a on a steering wheel side, and transmitting it to the second shaft 4b on a steered wheel 8 side, is arranged in the middle of a steering shaft of the vehicle. Moreover, the transmission ratio variable mechanism 30 includes a lock mechanism regulating the operation. Herein, when it is detected that a rate of change of torque that acts on the steering shaft exceeds a prescribed rate, the time required for the torque that acts on the steering shaft to reach a torque determination value is estimated, and on the condition that the estimated time falls within a prescribed time, the lock mechanism of the transmission ratio variable mechanism 30 is activated. |
