Zahnradfabrik Friedrichshafen, Ag.

Heinrich Holub

Dieter Elser

Rudolf Schurr

Auxiliary power steering system, especially for motor vehicles

Servo-assisted steering system for motor vechicles

A power steering gear assembly having a single control valve suitable for use in a single circuit type of power steering system, may be simply converted to use in a two-circuit type of power steering system by replacement of the steering spindle and the addition of a housing extension enclosing a second control valve formed on the replaced steering spindle. Both control valves include portions of the common steering spindle and control sleeves rotatable thereon, with one of the control sleeves being formed in one piece with the worm shaft of the steering gear assembly.

Auxiliary power steering for motor vehicles

A rotary plug steering valve of the worm gear type for auxiliary power steering of motor vehicles is provided with a rotary plug valve and a coacting valve sleeve including means for flow passage of return hydraulic fluid to a servomotor via an inner ported sleeve disposed within the valve plug, which sleeve also serves as an alignment and bearing member for the valve plug. The advantage achieved by thus providing additional serial flow control edges between the rotary plug and a return connection via the inner sleeve is the reduction of hissing flow noises in steering operations, by a throttling of return oil flow during the relative rotation of the valve plug and the inner sleeve. This reduces the cross section of return oil flow passage, but causes no throttling in neutral position of the valve for straight ahead steering when respective passages of the valve plug and inner sleeve are in full register.

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Schwabsich, Germany

Heinrich Holub