Patent ID: 6622832
Filing Date: 2003-09-23
Classification: F16F

Abstract:
A hydraulic shock absorber comprising:an outer cylinder having one end and an opposite end, said one end being closed; an annular cover member provided at said opposite end of said outer cylinder; an inner cylinder having one end associated with said one end of said outer cylinder, said inner cylinder further having an opposite end associated with said opposite end of said outer cylinder, and said inner cylinder being provided in said outer cylinder so as to form an annular reservoir chamber between said inner cylinder and said outer cylinder; a piston rod having one end and an opposite end, said one end of said piston rod being inserted into said inner cylinder, said opposite end of said piston rod extending through said cover member and projecting to an exterior of said outer cylinder; a cylindrical rod guide provided at said opposite end of said inner cylinder to slidably guide said piston rod; a rod seal provided at an inner periphery of said cover member in sliding contact with an outer periphery of said piston rod to seal between said piston rod and said cover member; a hydraulic fluid reservoir chamber formed between said rod seal and said rod guide to accommodate hydraulic fluid leaking out of said inner cylinder through said rod guide; a communicating hole provided in said rod guide to provide communication between said hydraulic fluid reservoir chamber and said annular reservoir chamber; and a check valve provided between said communicating hole and said hydraulic fluid reservoir chamber, said check valve including (i) a base portion, (ii) a peripheral portion extending obliquely outwardly from said base portion and terminating in a terminal portion that rests on a valve seat surface of said rod guide to allow hydraulic fluid in said hydraulic fluid reservoir chamber to flow toward said annular reservoir chamber through said communicating hole and to block flow of hydraulic fluid from said annular reservoir chamber toward said hydraulic fluid reservoir chamber, and (iii) a hydraulic fluid groove for guiding hydraulic fluid from said hydraulic fluid reservoir chamber to said terminal portion, said hydraulic fluid groove extending along said peripheral portion from said base portion to said terminal portion.