| 摘要 |
<p>PURPOSE:To prevent reduction of steering stability when tire pneumatic pressure is reduced via a gear ratio variable device of a steering system so as to ensure steering performance. CONSTITUTION:A steering force transmission device 60 is provided with a differential gear device 67 consisting of a planetary gear device and a gear ratio variable device consisting of a pinion carrier 72, a sector gear 73, a pinion 74, a stepping motor 75, and a motor controller 76. When tire pneumatic pressure is normal, a motor 75 is controlled at a predetermined steering gain characteristic which uses car speed and steering angle as parameters. When reduction of tire pneumatic pressure is detected by a control unit 50 which performs tire pneumatic pressure judgement control, the motor controller 76 obtains steering gain at a characteristic by which steering gain characteristic is changed to control the motor.</p> |
