Auxiliary power steering

An auxiliary power steering usable in motor vehicles for providing power steering which requires a substantially constant force on the steering wheel for activation, the auxiliary power steering having a steering valve assembly with a housing for providing fluid to a servomotor, said steering valve assembly comprising:

• a pinion arranged in an axial direction in the housing;
• first and second plungers located in said housing and mounted for movement in the axial direction from a neutral position to an activated position;
• first and second axially movable discs positioned axially concentric with said first and second plungers, respectively,
• first and second pressure springs each fixed at a first end in said housing with a second end positioned to exert pressure in the axial direction on said first and second plungers, respectively, to cause movement of said plungers from the neutral position to the activated positions responsive to rotation of said pinion;
• a third pressure spring fixed at a first end in said housing and having a second end attached to the first axially movable disc for exerting pressure thereon in the axial direction opposite the direction of the pressure exerted by the first pressure spring;
• first and second inlet-seat valves located in said housing and provided with inlet valve seats and first and second outlet-seat valves located in said housing, said first inlet-seat valve and said first outlet-seat valve having a first closing body associated therewith, and said second inlet-seat valve and said second outlet-seat valve having a second closing body associated therewith;
• each of said first and second closing bodies having a first end which forms an outlet valve seat and a second end positioned in abutment with said first and second axially movable discs, respectively, when said first and second plungers are in the neutral position, each of said closing bodies being provided with a feed chamber in fluid communication with said inlet-seat valve, each of said feed chambers including a protruding contact surface at the end thereof closest to the second end of each closing body which is adapted to rest on each of said inlet valve seats, respectively, when said plungers are in the neutral position, and said closing bodies being mounted for axial movement in said housing;
• and
• said first and second plungers each including an activation surface and a closing surface, each of said activation surfaces being positioned to engage the axially movable discs upon axial movement of said plungers, and each of said closing surfaces being positioned to abut said outlet valve seats of said closing bodies upon axial movement of said plungers beyond the point where said first and second activation surfaces engage respective axially moveable discs, to thereby close said outlet-seat valves and cause axial movement of said closing bodies whereby said first inlet-seat valve is opened when the first plunger is in the activated position and the second inlet-seat valve is opened when the second plunger is in the activated position.