| 摘要 |
<p>PURPOSE:To simplify the structure of a valve mechanism, by a method wherein a valve, which connects a main pressure chamber with an auxiliary pressure chamber and shuts off a communication between them, is provided to a small diameter part of a piston, as well as a groove to interconnect a reservoir with an auxiliary pressure chamber when a piston is in the returned position, is provided to a small diameter part of the piston. CONSTITUTION:The main pressure chamber 16 is formed in a small diameter hole 3 on the left side of a small diameter part 6 of a piston 5, while an auxiliary pressure chamber 17 is formed in a large diameter part 4 on the right side of a small diameter part 6. The long hole 8 is provided over a small diameter part 6 and a connecting part 9, while a groove 12, and an interconnecting groove 13 which interconnects the above-mentioned groove 12 and a hole 8, are provided to the external circumference of a small diameter part 6. The reservoir and an auxiliary pressure chamber are interconnected by these holes and grooves, when a piston is in the returned position. Further, a shaft 11, which forms a valve seat 10, is projected against an end of a small diameter part 6. The through hole 18 is provided to a small diameter part 6 from a shaft 11 to a long hole 8, and into above- mentioned hole 18, a valve part 20 equipped with a valve 19 is slidably inserted. Interconnection of a main pressure chamber 16 and an auxiliary pressure chamber 17, and shut-off of a communication between them are controlled by contacting and separating of a valve part 20 to and from a valve seat 10.</p> |
