Piston-cylinder unit particularly for shock absorber or compression strut

Claim 1

A piston-cylinder unit, particularly adapted for use as a shock absorber or compression strut comprising: a cylinder assembly having an axis, two axial ends and an outer circumferential surface; at least one hollow space defined within said cylinder assembly; a guide and seal assembly on one end of said cylinder assembly; a piston assembly which is axially moveable between an inner and an outer end position relative to said cylinder assembly, said piston assembly including a piston rod having an inner portion projecting into said hollow space through said guide and seal assembly and an outer portion arranged outside of said cylinder assembly; a cap assembly including a cap comprising an annular bottom which is essentially normal to said axis and a jacket, with said piston rod extending through said annular bottom and with said annular bottom being located adjacent that side of said guide and seal assembly which is remote from said hollow space, said jacket bearing against said outer circumferential surface of said cylinder assembly; a tubular body arranged on said outer portion of said piston rod, said tubular body being elastically compressible in the axial direction and being fastened in the axial direction on a fastening point of said piston rod with a part which faces away from said cap assembly, said tubular body together with said piston rod defining in the axial section between said fastening point and its end facing toward said guide and seal assembly an annular chamber which is open toward said cap assembly; closing means on said cap assembly for closing the annular chamber when said piston rod approaches said inner end position; and passage means on said cap assembly connecting said annular chamber to the atmosphere when an end of said tubular body facing toward said cap assembly bears against said closing means; said cylinder assembly including a tube forming the outer circumferential surface of said cylinder assembly and bent radially inwardly at its end facing toward said cap assembly in partial regions of its circumference, with axial projections of said cylinder being formed on said tube between said bent circumferential regions, said axial projections supporting said annular bottom of said cap assembly in the axial direction, said guide and seal assembly comprising a sealing member, said sealing member being axially coextensive with at least part of the axial length of said axial projections.