| 摘要 |
PURPOSE:To make it possible to absorb shock toward a propulsion unit without giving heavy stress to the propulsion unit by providing a means to throttle the area of a passage in a cylinder at the same timing as the lower part of the propulsion unit leaps up to attain the surface of the water. CONSTITUTION:When an under water obstacle collides against a lower part of a propulsion unit to compress a hydraulic oil in the first chamber 19 of a cylinder 18 above a fixed pressure, an absorber valve 35 opens to make the propulsion unit leap up. In this case, damping force based on the valve opening pressure of the absorber valve 35 and the passage resistance force of the first passage 101 provided with the valve 35 is strong at the time of collision occurring at the highest travelling speed of a piston rod 17 as shown by a broken line A, and then decreases as the travelling speed of the piston rod 17 slows down. When the lower part of the propulsion unit attains the surface of the water, a throttle valve 40 throttles the area of the first passage 101, and the damping force therefore rapidly grows larger according to throttle resisting force caused by the throttling of the valve 40 as shown by a broken line B, and then decreases again. |
