| 摘要 |
PURPOSE:To enable required functions to be secured even in unusual conditions wherein no pressure is supplied from outside by constituting a switchover valve which switches the telescopic motion of a piston sliding within a cylinder wherein an upper and a lower hydraulic chamber are formed, to be a normally closed type one which is closed when pressure supply from outside is released. CONSTITUTION:An upper and a lower hydraulic chambers A and B partitioned by a piston 20 is provided for a cylinder 20, and an oil passage L communicating the upper and the lower hydranlic chambers A and B with each other is concurrently provided as well. And then, a switchover valve 30 and a damping force build-up section 40 are provided for a base valve section 11 located underneath a cylinder 1. In addition, an outer cylinder 12 and an inner cylinder 13 are provided for the outside of the cylinder 1, and a reservoir C is concurrently provided between the outer cylinder 12 and the inner cylinder 13. In the constitution as described above, the switchover valve 30 is so constituted as to be a normally closed type one which is returned to an interrupting position so as to be closed when pressure supplied from outside is released. This constitution allows required functions to be secured even when no pressure is supplied from outside if a trouble has occurred in the hydraulic system. |
