| 摘要 |
<p>PURPOSE:To facilitate braking controls without need of large tread force by providing a valve which opens at a settled value and the other valve which opens at a larger settled value than its value on one side of pistons in a cylinder euqipped with large and small diametral bores. CONSTITUTION:The first and second pistons 9, 10 equipped with lands 5-7, 11 respectively engaged with its large and small diametral bores 3, 4 are housed in a cylinder member 1. Here, the piston 9 provides a rod member 37 in which fluid pressure in a chamber 13 moves to the right against a spring 45 when its arrives at the first settled value by left movement at the time of its braking and provides a valve 46 which closes a hole 40 by being moved by a spring 48 at the same time. Then fluid pressure in the chamber 13 is supplied into a hole 39 and a cylinder chamber 36. Besides, the piston 9 provides a valve 50 to open when fluid pressure becomes the second settled value which is higher than said pressure, and part of the fluid pressure is returned through a hole 38, a port 21 to a reservoir 24 by opening the valve 50.</p> |
