| 摘要 |
An hydraulic steering system for a ground-engaging, self-powered vehicle, the system including an engine driven primary pump for pumping hydraulic fluid to the steering system when the vehicle engine is operating and a wheel-driven secondary pump for pumping hydraulic fluid to the steering system when the vehicle is in motion, even if the engine or the engine driven primary pump is inoperable, or if the output of the engine driven primary pump is inadequate. The wheel-driven secondary pump is an over-center, axial piston pump which is controlled so that it is unidirectional in its output regardless of any change in direction of its input power source and which, thus, avoids the need for check valves in the hydraulic lines of the secondary pumping system, regardless of whether the vehicle is moving forward or in reverse when the engine becomes inoperable. |
