Power steering apparatus

A power steering apparatus for power steering the steerable wheels of a vehicle comprising:

• a steering wheel;
• a steering column having one end connected with said steering wheel and the other end operatively connected with the steerable wheels;
• a housing means for surrounding said steering column, wherein said housing means comprises a cylindrical housing having a threaded hole radially formed through the cylindrical side wall thereof;
• a torque sensor disposed in said housing means for detecting a steering torque exerted on said steering wheel by a driver;
• a lead line wound around said steering column and accommodated in said housing means, said lead line having one end electrically connected to said torque sensor and the other end to terminal means which is disposed outside said steering column;
• a motor installed on said housing means and operatively connected with said steering column for power assisting the steering column for power assisting the steering effort exerted on the steering wheel by the driver, said motor being driven to run in accordance with the steering torque detected by said torque sensor;
• rotation limiting means disposed between said steering column and said housing means for limiting the rotation of said steering column within a predetermined range, said rotation limiting means comprising:
• a cylindrical movable member disposed in said housing means for axial movement relative thereto, said movable member being fitted over said steering column and threadedly engaged at its inside surface with an outer peripheral surface of said steering column, said movable member having an axial elongated groove formed in its outer peripheral surface and over an entire axial length thereof;
• a restriction member disposed between said housing means and said movable member for restricting the rotation of said movable member relative to said housing mean while permitting the axial movement of said moveable member relative to said housing means, said restriction member comprising a screw threaded into the threaded radial hole in the cylindrical side wall of said housing, said screw having a tip projected into a slidably engaged with the elongated groove in said movable member;
• and
• stop means for limiting the range of axial movement of said movable member with respect to said steering column;
• and
• an O ring which is fitted on the tip of said screw and which is in sliding contact at its outer periphery with the surface of the elongated groove in said movable member for preventing the screw tip from directly contacting the groove surface.