Hydraulic shock-absorbing device

Claim 1

In a hydraulic shock-absorbing device for use in vehicles having a hydraulic cylinder containing a damping fluid and receiving therein a piston which divides the interior of said hydraulic cylinder into upper and lower chambers, said piston being connected to a piston rod which transmits external axial forces to said piston, and an outer casing provided concentrically with and exteriorly of said hydraulic cylinder to thus form a damping fluid storage chamber having an upper and a lower end, between the outside surface of said hydraulic cylinder and the inner surface of said casing, said storage chamber communicating at its ends with respective outer extremities of said upper and lower chambers so that the damping fluid in said lower chamber flows into said upper chamber and into said lower end of said storage chamber during a retraction stroke of said piston, and the damping fluid in said upper chamber flows into said lower chamber and into the upper end of said storage chamber during an extension stroke of said piston; the improvement comprising: a damping fluid cooling means disposed on said outer casing adjacent the lower portion of said storage chamber, said outer casing having upper and lower through holes formed therein and spaced apart along the direction of the longitudinal axis of said hydraulic cylinder, said through holes communicatively connecting said damping fluid cooling means with said storage chamber; an annular member means disposed in said storage chamber so as to be interposed between said hydraulic cylinder and said outer casing at a position intermedIate between said two through holes, said member means partitioning said storage chamber into upper and lower parts; and a vehicle weight carrying suspension coil spring disposed around said outer casing substantially above said cooling means, said improvement operating whereby when said damping fluid is caused to flow into a respective one of said upper and lower parts of said storage chamber, it flows into the other part of said storage chamber through said lower through hole, said damping fluid cooling means and said upper throughhole, thus executing forced circulatory motion inside said shock absorber to cause continuous cooling of said damping fluid.