| 摘要 |
A hydraulic control system for, e.g., electrically driven vehicles, comprising a hydraulic, double-acting steering piston-cylinder device which co-acts with a control unit which is actuable by means of a steering member, and which is connected to a hydraulic pump, driven by an electric motor, and to a tank, and which includes a control signal outlet through which a control signal is delivered for maintaining and interrupting the supply of steering hydraulic fluid to the steering-piston cylinder device. In order to enable the vehicle to be steered directly, even when the pump is not activated, an accumulator (20) is provided in the hydraulic connection (12) between the pump (11) and the control unit (8), at a location between two counter-directional check valves (17, 19) which prevent the flow of hydraulic fluid from the accumulator (20) and of which valves the valve located upstream of the accumulator (20) is intended to open in response to the control signal delivered by the control unit (8), this control signal constituting a pressure increase, so as to permit hydraulic fluid to flow from the accumulator (20) to the steering piston-cylinder device (1). The system also includes means (39, 40) operative to start the pump motor (13) upon the occurrence of a pressure decrease in the hydraulic connection (12) between the two check valves (17, 19), therewith to provide the requisite flow of hydraulic steering fluid through the action of the pump (11). |
