| 摘要 |
A power assist steering assembly for a vehicle comprises a power assist actuator, a pump for supplying pressurized fluid to the power assist actuator, and a steering control valve comprising a movable valve member for controlling flow of pressurized fluid to the power assist actuator. A conduit that communicates pressurized fluid from the pump to the steering control valve comprises a restriction orifice. A conduit device controls the flow of pressurized fluid through the restriction orifice in accordance with vehicle speed. A mechanism is provided to resist movement of the valve to increase flow of pressurized fluid to the power assist actuator with a force which increases as vehicle speed increases. The mechanism comprises a first fluid chamber, a spring located in the first fluid chamber for biasing the valve member to a neutral position thereof, and a second fluid chamber the pressure in which counteracts the action of the spring. First and second conduits communicate the first and second fluid chambers with the downstream and upstream sides of the restriction orifice, respectively. |
