| 摘要 |
PURPOSE: A cylinder assembly for PET(Polyethylene Terephthalate) bottle production is provided to reduce the cost for maintenance by restraining wear of a piston reciprocating in a cylinder block. CONSTITUTION: A cylinder assembly(1) includes a cylinder block(2), sleeves(4,4a)) and a stack casing(5) interferingly fitted in the cylinder block, and a piston(3) reciprocating in the cylinder block and in contact with the sleeve and the stack casing with its outer face. When the piston reciprocates in the cylinder block for compressed air distribution, the outer face of the piston is in contact with sealing bodies(9,9a) placed on the inner face of the sleeve and the stack casing. Since the sealing bodies have hardness lower than that of the piston, wear of the outer face of the piston is restrained. Vicariously, the sealing bodies are worn out. If airtightness between the sleeve and the stack casing is degraded by the wearing out of the sealing bodies, airtightness is kept by changing the sealing bodies.
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