| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic auto tensioner that can suppress drastic reduction in a contact area of a close contact part to a collar due to heat shrinkage of a spring seat after molding and can ensure good sealing performance in the close contact part.SOLUTION: A sleeve 5 is installed within a cylinder 1 in which working fluid is stored, and a spring seat 8 comprising a synthetic resin molded product is installed in an upper part of a rod 6 having a lower end slidably inserted into the sleeve 5. A seal member 14 incorporated into an opening of the cylinder 1 is brought into elastic contact with an outer diameter surface of a metallic collar 13 having an upper part insert-molded to the spring seat 8, so as to form a reservoir chamber 15 within the cylinder 1. An inverted part 13a folded back downwards at approximately 180° is installed at an upper end of the collar 13, so as to increase a contact area to the resin-molded spring seat 8. When the molded spring seat 8 is thermally shrunk, the shrunk resin is brought into close contact with the inverted part 13a to suppress drastic reduction in the contact area of the close contact part, so as to secure airtightness. |
