Patent ID: 6152254
Filing Date: 2000-11-28
Classification: B62D

Abstract:
A power steering system (10) for a vehicle having dirigible wheels (13), a power cylinder (18) having left and right ports (56 and 58) and adapted to supply a powered assist to steering the dirigible wheels (13) of the vehicle upon the supply of a pressurized fluid to one of the left and right ports (56 and 58), a reversible fluid pump (24) having first and second ports (78 and 80), an electric motor (26) operatively connected to and capable of reversibly driving the fluid pump (24), a first fluid line (20) connecting the first port (78) of the fluid pump (24) to the left port (56) of the power cylinder (18), a second fluid line (22) connecting the second port (80) of the fluid pump (24) to the right port (58) of the power cylinder (18), a pair of check valves (52) disposed in a suction line (49) connected to a fluid reservoir (50) and connected one each to the first and second fluid lines (20 and 22), and a primary applied steering torque sensor (14) which generates a signal (V.sub.TT) in response to at least an applied steering torque (T.sub.s); the improvement wherein the system (10) further comprises:a first pressure transducer (54) sensing a left fluid pressure (LP.sub.p) in the first fluid line (20);a second pressure transducer (55) sensing a right fluid pressure (RP.sub.p) in the second fluid line (22); andan electronic control means (32) to which the first and second pressure transducers (54 and 55) and the primary applied steering torque sensor (14) are operatively connected, and which controls actuation of the electric motor (26);wherein the electronic control means (32) establishes servo control (322, 342) over the powered assist to steering supplied by the power cylinder (18) in dependence upon the fluid pressure (LP.sub.p or RP.sub.p) sensed by one of the first and second pressure transducers (54 or 55).