Provided is a spring sleeve for a piston cylinder unit, wherein the spring sleeve is adapted to receive a spring, at least partially, and to guide it, wherein the spring sleeve has a cylindrical sleeve inner surface. The embodiment further relates to a cylinder for a piston cylinder unit, wherein the cylinder) is adapted to be arranged inside a spring of a piston cylinder unit. The embodiment also relates to a piston cylinder unit, including a cylinder, a spring arranged concentrically around the cylinder, and an inner spring sleeve and outer spring sleeve each arranged concentrically around the spring, wherein the cylinder and the spring are arranged inside the inner spring sleeve and the outer spring sleeve. Finally, the embodiment relates to a method of manufacturing such a piston cylinder unit.

An exemplary shock absorber includes a damper tube, a damper piston, a piston shaft, and at least two different surface treatments. The damper tube includes an interior surface. The damper piston includes a piston surface that engages the interior surface. The piston shaft couples with the damper piston and includes a shaft surface that engages a fourth surface. The at least two different surface treatments are disposed on at least one of the interior surface and the shaft surface and create a corresponding plurality of coefficients of friction with at least one of the piston surface and the fourth surface respectively.

According to the present invention, there is provided a slide member for a shock absorber of a vehicle including a back metal, a porous sintered metal layer containing a porous sintered metal formed on the back metal and a resin with which the porous sintered metal is impregnated and covered, and a resin slide layer formed on the porous sintered metal layer and having a smooth slide surface, and the slide member is formed in a cylindrical shape so that the resin slide layer is disposed on an inner peripheral side. The resin slide layer is composed of polytetrafluoroethylene and a plurality of granular elements dispersed in the polytetrafluoroethylene, and the granular element is composed of molybdenum disulfide and molybdenum trioxide, and/or tungsten disulfide and tungsten trioxide.

A shock strut for a landing gear assembly that includes a hollow cylinder having a first bearing surface and a piston having a second bearing surface. The piston is configured to move within the hollow cylinder such that the second bearing surface slides relative to the first bearing surface. One of the first and second bearing surfaces includes a non-metallic material and the other of the first and second bearing surfaces includes cold worked titanium.