| 摘要 |
<p>PROBLEM TO BE SOLVED: To quicken pressure increase on a primary side in a vacuum force feeding time so as to eliminate unstable behavior of a secondary piston and so as to prevent damage in a ring type seal member. SOLUTION: A primary pressure chamber 26 is formed between a freely slidable primary piston 24, which is inserted into a cylinder hole 23 formed in a cylinder housing 20, and a secondary piston 25, while a secondary pressure chamber 27 is formed on the outer end side of the secondary piston 25, in which a ring type seal member 28 is arranged in the outer circumference. In the ring type seal member 28, a lip 29 cutting off communication between the primary pressure chamber 24 and a reservoir 17 during usage is arranged, and when fluid is introduced from the reservoir 17 to the primary pressure chamber 24 and to the secondary pressure chamber 25, the lip 29 is deformed because of a differential pressure longitudinally working on the seal member 28, so that inflow of the fluid from the reservoir 17 to the primary pressure chamber is allowed.</p> |
