Auxiliary pump arrangement and a power steering system comprising such auxiliary pump arrangement

An auxiliary pump arrangement for providing a flow of hydraulic fluid to a power steering system of a vehicle, the auxiliary pump arrangement comprising:

• an auxiliary pump having a pump inlet configured to receive a flow of hydraulic fluid from a primary power steering pump via a hydraulic supply conduit, and a pump outlet;
• an actuator connected to the auxiliary pump, the actuator comprising a clutch connectable to a driveline of the vehicle;
• a biasing member operable to exert a first pressure on the clutch for urging the clutch towards the driveline;
• a chamber accommodating a piston member of the actuator, the piston member dividing the chamber into a first compartment and a second compartment, wherein the first compartment is configured to receive at least a portion of the flow of hydraulic fluid from the hydraulic supply conduit for exerting a second pressure on the piston member to urge the clutch away from the driveline, the first compartment comprising a first outlet, the first outlet being arranged in fluid communication with the pump outlet of the auxiliary pump;
• and
• a first one-way valve in fluid communication between the first outlet and the pump outlet, the first one-way valve being configured to prevent hydraulic fluid from the pump outlet to reach the first outlet;
• wherein the auxiliary pump arrangement is configured to assume an engaged state in which the clutch connects the auxiliary pump to the driveline when the first pressure exceeds the second pressure, and a disengaged state in which the clutch disconnects the auxiliary pump from the driveline when the second pressure exceeds the first pressure.