Patent ID: 6122912
Filing Date: 2000-09-26
Classification: B62D

Abstract:
A regenerative power steering system (10) for a vehicle, alternatively operable in an unassisted, straight steering mode, a powered assist mode which provides a powered assist to entry of the vehicle into a turn and an energy regeneration mode which recovers energy while the vehicle exits a turn; wherein the system (10) employs a fluid, and wherein the system (10) comprises:a power cylinder (18);a valve assembly (38) fluidly connected to and controlling actuation of the power cylinder (18);a fluid delivery line (20) fluidly connected to the valve assembly (38);a reservoir structure (76) fluidly connected to the valve assembly (38);a motor pump (24) having an outlet port (78) and an inlet port (80);means (28) for switching the system (10) between the straight steering, powered assist and energy regeneration modes, comprising a four-way cross-over valve (30) operable between: (a) a first position associated with the powered assist mode of the system (10), in which the four-way cross-over valve (30) fluidly connects the motor pump outlet port (78) to the fluid delivery line (20) and fluidly connects the motor pump inlet port (80) to the reservoir structure (76); and (b) a second position associated with the energy regeneration mode of the system (10), in which the four-way cross-over valve (30) fluidly connects the motor pump outlet port (78) to the reservoir structure (76) and fluidly connects the motor pump inlet port (80) to the fluid delivery line (20); anda motor generator (26) operatively connected to the motor pump (24), the motor generator (26) driving the motor pump (24) so as to provide a flow of pressurized fluid to the valve assembly (38) and the power cylinder (18) during the powered assist mode of the system (10), and the motor generator (26) generating energy recovered through the motor pump (24) during the power regeneration mode of the system (10).