| 摘要 |
<p>PURPOSE:To improve the yield of a material, by composing a piston of a first portion, at one end of which a small-diameter part to be fitted in a small cylinder bore is provided, and a second portion, which has a good sliding property and is fitted in a large cylinder bore and on the other end of the first portion. CONSTITUTION:A stepped piston 10, which extends to a pneumatic section 3, is slidably inserted into a cylinder hole 4 having a large and a small parts 6, 7. The stepped piston 10 comprises a rodlike first portion 11 having a small-diameter part 70 at the left-hand end, and an annular second portion 12 liquid-tightly fitted on the thickness-decreased part 13 of the first portion. The small-diameter part 70 is slidably fitted in the small part 7 of the cylinder hole 4. The second portion 12 is slidably fitted in the large part 6 of the cylinder hole 4. The second portion 12 is made up of an annular member 14 integrally molded from a synthetic resin of good sliding property.</p> |
