Patent ID: 6234928
Filing Date: 2001-05-22
Classification: F01L,F16H

Abstract:
A ratchet tensioner, comprising:a tensioner housing having a plunger accommodation bore formed therein;a plunger having an outer circumferential surface slidably fitted into said plunger accommodation bore of said tensioner housing and urged by a spring such that a tip portion of said plunger is projected to the exterior of said plunger accommodation bore; anda ratchet pivotally supported on a ratchet pin provided on said tensioner housing;said tensioner being configured such that a ratchet pawl formed on said ratchet is in mesh with rack teeth formed on an outer surface of said plunger so as to prevent said plunger from receding into said plunger accommodation bore; whereinsaid plunger accommodation bore of said tensioner housing has an inner circumferential surface formed of an aluminum containing metallic material for direct sliding contact with said outer circumferential surface;a hard alumite layer having a thickness of 5 to 50 .mu.m is formed on said inner surface of said plunger accommodation bore; anda lubricant is held within said alumite layer, and is adapted to lubricate said sliding contact.