| 摘要 |
PURPOSE:To aim at miniaturizing a power steering device, by controlling the distance between the fulcrum point and acting point of a control lever in accordance with the running conditions including the speed and steered angle of a vehicle, etc. to change its lever ratio, thereby it is possible to eliminate the necessity of a hydraulic reaction mechanism. CONSTITUTION:When a steering wheel (not shown) is rotated so that a pinion shaft 13 rotates associatingly, the pinon shaft 13 swings due to the change-over resistance obtained at this time. This swing causes a control level (a) having its acting section 11 inserted in a communication hole 10 in a spool 2 in a change-over valve C to swing between the acting section 11 and a circular force point section 12 about a rod-like fulcrum section 14, as a center point, which is positioned on the opposite side, thereby the spool 2 is changed over in the swinging direction. In this arrangement, when controller 25 changes the rotational speed of a motor 24 in accordance with the running conditions of the vehicle to change the discharge amount of a pump 21, a piston 15 in a control chamber (b) is displaced, and the contact point between the annular bead 19 of the piston 15 and the fulcrum section 14, that is, the lever ratio, is changed, thereby it is possible to adjust the operating force of the steering wheel. |
