| 摘要 |
PURPOSE:To control damping force in multistage according to the running conditions by incorporating switch means capable of controlling the connection of passages connecting chambers on both sides of a piston in multistage in the internal end portion of a piston rod of a hydraulic draft gear. CONSTITUTION:A twin-tube hydraulic draft gear has a piston rod 14 movably inserted in an inside cylinder 12. A piston not shown is mounted on the end portion 15 of the piston rod 14. In this case, a hole for a coil is formed on the internal end portion of the piston rod 14, and the first and second passages 32, 34 are formed as a by-path. A core 44 is disposed in the hole 24, and the core 44 is provided with an axial through hole 46 and with the third and fourth passages 48, 50 connecting the first and second passages 32, 34. A plunger 56 deviated to a neutral position by springs 78, 80 is fitted in the above through hole 46, and slid to displace by controlling the electricity applied to coils 70, 72 wound round both ends of the core 44. |
