| 摘要 |
PURPOSE:To prevent occurrence of fluid noise by providing a variable throttle mechanism for increasing the back pressure of working oil in a power steering unit while interlocking with a hydraulic control valve. CONSTITUTION:Upon rotary operation of a steering wheel to rotate a stab shaft 2 in predetermined direction, to the left for example, a hydraulic control valve 6A will move to the left thus to move a throttle valve 23 synchronously in a valve containing hole 12. Consequently, predetermined differential hydraulic pressure is produced between two operating chambers 9, 10 to move the piston to the left thus to assist motion of a steering member 11 and to control steering of wheel. The throttle valve 23 will gradually choke the exhaust control orifices 26a, 26b thus to gradually increase the back pressure of working oil to be discharged selectively from said chambers 9, 10 through hydraulic exhaust sections 6b, 6b. Consequently, the differential pressure across said sections 6b, 6b can be reduced to prevent occurrence of fluid noise. |
