| 摘要 |
PURPOSE:To equalize set loads applied on control springs even when a pressure difference exists between two pressure systems at the time of reducing the pressure in a tandem cylinder by a method wherein a second spring adopted to push a free piston located between the liquid pressure control valves toward one side is provided. CONSTITUTION:Each of the liquid pressure control valves belongint to two pressure systems comprises a piston 4a (or 4b), a poppet valve 6a (or 6b) and the control spring 5a (or 5b) and the free piston 9 is provided between the two valves. Further, a spring seat 11 is provided between the control spring 5b belonging to one of the pressure system relating to primary liquid pressure and the free piston 9 and the second spring 12 is attached to the spring seat 11. Consequently, even when a secondary liquid pressure becomes higher than the primary liquid pressure at the time of reducing a braking pressure, the useless movement of the free piston 9 does not occur because the piston 9 is thrusted by the second spring 12 and accordingly, it is possible to keep uniform the set loads applied on the control springs 5a and 5b. |
