| 摘要 |
<p>A power steering mechanism for a vehicle which comprises a housing defining a cavity in which is rotatably mounted a rotary steering control member, with a driving piston connected to a member in the steering gear of the vehicle, the piston separating two pressure chambers of the housing. The driving piston also comprises a bore having an open end through which axially extends a screw-threaded spindle of the rotary steering control member. A disc-shaped distributing chamber is defined in said driving piston, and is coaxial with the spindle. The piston supports a nut element in screw-threaded engagement with said screwthreaded spindle, said nut element being prevented to move axially with respect to the piston, and allowed to rotate within a limited angular range. A star-shaped rotor comprising a central portion from which extends a plurality of radial arms is rotatably mounted in the disc-shaped chamber and separates the latter into a first set and a second set of distributing chambers respectively connected to the first and second pressure chambers of the housing. The disc-shaped rotor is connected in rotation with the nut element, fluid inlet and outlet passages respectively connectible to the high pressure side and the low pressure side of a pressure source being provided in said driving piston to communicate with the disc-shaped chamber through respective openings. The openings cooperate with the arms of the rotor to control distribution of the fluid pressure to the first and second pressure chambers as a function of the relative angular position of the piston and rotor.</p> |
