| 摘要 |
The present invention concerns a hydraulic power-assisted steering gear for vehicles. A servo-cylinder is controlled by means of a control valve whose control spool can be deflected, independently of the position of the driven link, by actuation of the steering wheel from a neutral position corresponding to a steady driving condition. In addition, the control position of the control spool can also be adjusted automatically by means of a return device and under the action of a displacement force in such a way that when the steering wheel is released, the wheels of the vehicle are caused to return automatically from a deflected position into the straight position. A corresponding displacement of the control spool is achieved by subjecting its end surfaces to hydraulic pressure. The control of the corresponding pressure head is controlled as a function of the deflection angle by means of a further control valve. The return device is a particularly simple and robust device of small installation dimensions which also has the capability of achieving any given variation of return force with deflection angle. |
