| 摘要 |
PROBLEM TO BE SOLVED: To prevent drift of a steering wheel in the neutral condition in which steering is not carried out so as to accomplish improvement in a sense of stability of the steering wheel, a steering wheel holding feeling based on a constant assist force necessary for holding the steering wheel in its operation, and reduction in a load of a capacity variable pump in the steering end when the steering wheel is turned fully in a servo valveless power steering device. SOLUTION: A power steering device is provided with a capacity variable pump provided with a cam ring 40 eccentrically moving at the tip of a steering column, and according to the eccentric movement of the cam ring 40 due to steering, capacities of the pump chambers 42, 44 are changed so that capacity of pressure fluid to be fed to cylinder chambers 30, 32 in a power cylinder 26 and its feeding direction are changed, and as a result, an assist force is applied to a steering rod 14. Between one pump chamber 42 and the other pump chamber 44, a variable throttle whose opening area is varied according to a steering force is communicatingly arranged, and between two paths connecting the capacity variable pump to the cylinder chambers 30, 32 in the power cylinder 26, a shuttle valve 83, which introduces pressure fluid on the high pressure side to a back pressure groove of a vane of the capacity variable pump, and a capacity fluctuation absorption member 84, which allows capacity fluctuation of the pressure fluid due to the oil temperature, are arranged. |
