| 摘要 |
PROBLEM TO BE SOLVED: To provide a power steering device for a vehicle, the device capable of always actuating each hydraulic pump in a region with good efficiency by properly switching a driving state of two hydraulic pumps, and thereby suppressing deterioration in fuel economy by reducing electric power consumption of a pump driving motor.SOLUTION: When a required discharge rate set in accordance with steering operation is within a range with good discharge efficiency of a first hydraulic pump, the first hydraulic pump is driven by a first motor to achieve the required discharge rate. When the required discharge rate is increased and enters a region with bad discharge efficiency of the first hydraulic pump, at the time point when the rotation speed of the first motor immediately before the entrance reaches a switching determination value N0, the driving of a second hydraulic pump is started by a second motor, and the required discharge rate is established by the cooperation of the first and second hydraulic pumps. Accordingly, the first and second hydraulic pumps are always actuated in regions with good discharge efficiency. |
