| 摘要 |
PURPOSE:To securely separate both left and right cylinder chambers from each other and generate an appropriate auxiliary steering force, by providing a controlling valve in a bypass passage connecting both of the cylinder chambers to each other. CONSTITUTION:When a pump 10 is stopped, no pressure difference is generated between hydraulic pressure signal passages 30 and 32, so that a valve body 26 is located at a position on the upper end side of a value hole 23 by the force of a spring 27, thereby forming the bypass passage 20 which short-circuits the left and right cylinder chambers 15a, 15b of a power cylinder 15 to each other. When the pump 10 is operated to start feeding a hydraulic oil, the resultant hydraulic pressure is introduced into a high-pressure chamber 29 through the signal passage 30, whereby the valve body 26 is moved to the side of a low-pressure chamber 31 against the force of the spring 27. With the valve body 26 thus moved, an annular groove 25 is disconnected from passage holes 28a, 28b constituting the bypass passage 20, so that the passage 20 is cut off. |
