| 摘要 |
A power steering mechanism for a vehicle which comprises a rotary steering control member and a driving piston connected to a member in the steering gear of the vehicle. The piston separates two pressure chambers in the housing. The mechanism also comprises a shaft of which the first end defines a screw cooperating with a nut attached to the piston. A pressure fluid distribution valve is adapted to control fluid communication between the pressure source formed by a pump, and the two pressure chambers. The distribution valve is of the rotary type and comprises a sleeve moving as a whole with the rotary control member and a rotor moving in unison with the shaft. The shaft and the rotor are connected to opposite ends of a torsion bar. The second end of the shaft is broadened and contains a bore. This other end is provided with orifices and defines the sleeve of the rotary valve, in which the rotor is mounted for rotation. The second end of the shaft is rotatably mounted in the housing by means of a single ball thrust bearing which is constructed as follows: the inner ball race is a groove in the outer periphery of said second end. The outer ball race is formed on two complementary rings held axially and radially in the valve cover of the housing.
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