A shock absorber includes an outer tube, an inner tube fitted to the outer tube so as to be able to move forward and backward, a cylinder provided inside the outer tube and extending inside the inner tube, a rod extending from an end portion of the inner tube exposed from the outer tube to an inside of the cylinder, and a piston which is provided on the rod and divides the inside of the cylinder to form a gas chamber. On an outer peripheral surface of the piston, a first lubricating member, a first seal member, and a second seal member are provided in this order from a side closest to the gas chamber to a side away from the gas chamber. The members are in sliding contact with an inner peripheral surface of the cylinder.

A gas cushion device includes a cylinder, a piston slidably fitted in the cylinder, a gas enclosed in the cylinder to energize the piston, and an oil feeding mechanism configured to feed a lubricating oil to a fitting portion between the cylinder and the piston. The cylinder and the piston are fitted in an interference fit state. The piston is reduced in diameter from an inside of the cylinder toward the outside of the cylinder.

Provided are a lubricant composition for shock absorbers, a lubricant additive, and a method of adjusting frictional property of a lubricant composition for shock absorbers, each capable of satisfying both the steering stability and ride comfort. The lubricant composition for shock absorbers contains a base oil and pentaerythritol esters and having frictional property represented by the following formula (1):

[00001]$\begin{array}{cc}\text{RI}\text{>}\text{1}\text{.75}\times {\text{F}}_{\text{ave}}\text{-}\text{0}\text{.05}& \text{­­­(1)}\end{array}$

supposing that a ratio ({F.sub.sa - F.sub.ave} / F.sub.ave) of a difference, at the time of minute amplitude, between a peak frictional force F.sub.sa in transition from a stationary state to a sliding state and an average frictional force F.sub.ave to the average frictional force F.sub.ave at the time of minute amplitude is responsiveness RI.

A shock absorber arrangement for a vehicle suspension contains a shock absorber having a damper cap and a piston rod, and a supplementary spring which is arranged on the piston rod opposite the shock absorber and has an outer surface facing the damper cap and an inner surface facing the piston rod, and is configured for damping the movement of the shock absorber in the direction of the piston rod on contact with the damper cap. The outer surface and/or the inner surface is at least partially coated with a lubricant.

A sealing device for hydraulic equipment according to the invention includes an outer member having an annular shape, an inner member inserted into the outer member, and a seal ring housed in an annular groove disposed in the outer circumference of the inner member and abutting on the outer member to prevent a liquid from passing through a gap between the outer member and the inner member. The annular groove of the inner member has a bottom portion including a recess for restraining axial displacement of the seal ring relative to the annular groove.

The present invention relates to a lubricating oil composition for drive system apparatus having excellent wear resistance and oxidation stability and a method for producing the same, a lubrication method of a drive system apparatus using the foregoing lubricating oil composition, and a drive system apparatus.

A suspension array includes a support rod, an elastic member wound around the support rod, a housing supported by the elastic member and including a compartment surrounding the support rod, the support rod being coupled to the housing while penetrating the housing in the longitudinal direction, a friction member installed inside the housing to cause friction with the support rod when the friction member in the compartment is displaced, and a cap penetrated in the longitudinal direction by the support rod and coupled with the housing to cover the compartment, wherein the support rod penetrates the cap along the longitudinal direction and wherein the housing includes one or more first holes configured to discharge, to the outside, condensate generated in an inner space defined by the coupling between the cap and the housing.

There is provided a damper assembly for a helicopter rotor. The damper assembly comprises a piston movable along an axis, a piston shaft connected to and axially movable with the piston along the axis, and a bushing configured to surround the piston shaft and guide the piston shaft for movement along the axis. The bushing comprises a surface configured to oppose the piston shaft and guide the piston shaft for movement along the axis. The piston shaft comprises a surface configured to oppose the surface of the bushing. A clearance is provided between the surface of the piston shaft and the surface of the bushing so as to provide a passage for fluid to flow between the bushing and the piston shaft in use.

A shock absorber includes an outer tube, an inner tube fitted to the outer tube so as to be able to move forward and backward, a cylinder provided inside the outer tube and extending inside the inner tube, a rod extending from an end portion of the inner tube exposed from the outer tube to an inside of the cylinder, and a piston which is provided on the rod and divides the inside of the cylinder to form a gas chamber. On an outer peripheral surface of the piston, a first lubricating member, a first seal member, and a second seal member are provided in this order from a side closest to the gas chamber to a side away from the gas chamber. The members are in sliding contact with an inner peripheral surface of the cylinder.

A fluid damping structure is provided that includes an inner and outer annular elements, first and second ring seals, first and second outer annular seals. The inner annular element has an outer radial surface and a plurality of annular grooves disposed in the outer radial surface. The outer annular element has an inner radial surface. A damping chamber is defined by the inner and outer annular elements, and the first and second inner ring seal. A first lateral chamber is disposed on a first axial side of the damping chamber. A second lateral chamber is disposed on a second axial side of the damping chamber. A plurality of fluid passages are disposed in at least one of the inner annular element or the inner ring seals. The fluid damping structure is configurable in an open configuration and a closed configuration.