A hydraulic damper for a vehicle including a main tube. A first piston assembly is slideably disposed in the main tube and axially divides the main tube into a rebound chamber and a primary compression chamber. A hydraulic compression stop assembly is disposed in the primary compression chamber and includes a narrowed section extending between an open end and a closed end. A second piston assembly is slideably disposed in the narrowed section and is coupled with the first piston assembly. The second piston assembly has a piston tube that extends between an opened end and a shut end. A displaceable partition is slideably disposed in the piston tube. A first auxiliary compression chamber is defined between the partition and the closed end of the narrowed section. A second auxiliary compression chamber is defined between the partition and the shut end of the piston tube.

Disclosed are a compound impact-resistant device and an application thereof. The compound impact-resistant device includes an inner cylinder, a first pressure sensor and an outer cylinder; an inner cavity of the inner cylinder is connected to a magnetorheological damper, a spiral valve element, a floating piston and a spring from bottom to top; and the outer cylinder is connected to a piston rod, a bottom end of the piston rod penetrates a top of the inner cylinder, the spring and the floating piston to be connected to the spiral valve element, and a portion below the spiral valve element is filled with hydraulic oil. The compound impact-resistant device can provide specific initial support force and achieve active self-adaptation to dynamic impact, thus solving the problems that traditional hydraulic buffers cannot provide initial support force and traditional mechanical crushing members have difficulty in providing large support force.

Housing has first and second parallel tubular chambers. The first chamber contains a gas spring whose output shaft connects to a first piston of area A.sub.1. The second chamber contains a second piston of area A.sub.2<A.sub.1. Piston A.sub.2 connects to the device's output shaft. The housing has a valve block with an internal port in fluid communication with the two chambers between the first and second pistons. The valve block contains an incompressible fluid. A poppet valve is in the internal port. The poppet includes a flow restricting bore therethrough. A force on the output shaft causes the fluid to force open the poppet and displace the piston, A.sub.1, storing energy in the gas spring. Upon removal of the force on the device's output shaft, the gas spring pushes the fluid to close the poppet. Hence, only a low volume flow through the bore in the poppet is permitted.

An apparatus and system for attaining maximum unidirectional response to vibration damping of a printed circuit board (PCB) or other planar surface utilizing a defined travel displacement of a single tungsten (or other material) cylindrical rod in a single or plurality of sealed cylindrical chambers in a particle impact damper (PID). The single tungsten (or other material) cylindrical rod is not weighed down, constrained, encumbered within the chamber; accordingly, providing unrestricted freedom for the cylinder to quickly respond in a unidirectional direction at the first occurrence of excessive vibrational acceleration over 1G. The structure of a single cylindrical particle within a sealed cylindrical chamber also provides a path of minimum distance for the cylinder to travel before colliding with the ceiling or floor of the PID chamber. A plurality of cylindrical chambers can be arranged in a variety of patterns within the PID housing such as desired. The PID housing can be any shape such as a cube, a rectangular cuboid, a cylinder, sphere, triangular tetrahedron, triangular prism, polygon, toroid or any combination of shapes.

A hydraulic damper includes a hydraulic compression stop arrangement having an insert including a bottom and a fixing member including a body. The bottom is attached to the body through a locking connection preventing axial movement of the insert and transferring pressure exerted on the insert to the fixing member and allowing the cavity of the insert to receive the additional piston during the compression stroke to provide an additional damping force. The body includes a locking plate and the bottom includes a locking yoke with the locking yoke being secured to the locking plate to define the locking connection. The fixing member includes a head and the locking plate extends radially outwardly from the head defining a recess extending about the center axis. The locking yoke, having an arcuate shape and an L-shaped cross section, extends axially outwardly from the bottom to engage the recess forming the locking connection.

Provided are a volume change compensation device capable of reducing a manufacturing burden with a simple configuration and a damper device including the volume change compensation device. A damper device 100 includes a rotary damper, and includes a volume change compensation device 140 in a shaft 121 of a rotor 120. The volume change compensation device 140 includes an inner cylinder piston 142 pressed by an inner cylinder piston pressing elastic body 145 in a body tube 141 communicating with a hydraulic fluid housing portion 103 of the damper device 100 through a connection path 141a. The inner cylinder piston 142 is formed in a bottomed cylindrical shape opening on a connection path 141a side. In the inner cylinder piston 142, an inner cylinder inner small piston 143 is pressed against a bottom portion 142b by a small piston pressing elastic body 144. An air hole 142c is formed at the bottom portion 142b of the inner cylinder piston 142. The inner cylinder inner small piston 143 slides in the inner cylinder piston 142 according to the amount of hydraulic fluid 150 in the inner cylinder piston 142.

A vibration damper includes an end-stop control valve that progressively adds end-of-stroke damping force to complement the damping force provided by a main piston. The end-stop control valve may include a valve piston assembly that has a valve piston insert, a piston that is disposed radially outside the valve piston insert, and a valve disc stack-up that is supported on a hub of the valve piston insert and a valve seat of the piston. The valve piston insert and the piston may be arranged so as to be longitudinally movable relative to one another. Consequently, the preload of the valve disc stack-up increases as the valve piston assembly contacts a catch piston and begins end-of-stroke damping. Transitioning from an initial preload to a maximum preload during the end-of-stroke damping event progressively increases damping resistance and thereby improves NVH characteristics.

A device for controlling fluid flow in a shock assembly is disclosed. The device includes a single adjustable fluid circuit configured for controlling a damping force associated with multiple compression forces. The single adjustable fluid circuit comprises a fluid passageway through a base valve and a positionally adjustable piston assembly with a floating shim stack positioned at one end of the fluid passageway, the positionally adjustable piston assembly with the floating shim stack configured for selectively blocking a flow of fluid through the fluid passageway.

A shock absorber has a main piston and a compression piston, connected by a compression piston housing. In stage 1, the shock absorber operates as a conventional monotube, with the damping force being generated only by the main piston. In stage 2, the compression piston travels into the compression housing, as the shock absorber still operates as a monotube damper. In stage 3, the compression piston is now significantly increasing its compression damping force by supplementing the main piston. The oil volume in the compression piston housing passes through the compression piston, causing an increase in compression damping force.

An end-stop control valve can progressively add end-of-stroke damping resistance to complement the damping force provided by a main piston in a damper tube. The end-stop control valve may include a piston that is secured on a piston rod and selectively engages a catch piston, both of which are longitudinally movable within the damper tube. As the piston approaches the catch piston, an annular pocket of hydraulic fluid is created longitudinally and radially between the piston and the catch piston. As the piston continues to approach the catch piston, a cross-sectional area through which hydraulic fluid exits the pocket decreases, thereby gradually increasing the resistance of the end-stop control valve. In addition, a spring disc secured on the piston rod may contact a valve seat on the catch piston and provide resistance by elastically deforming in a longitudinal direction before the contact surfaces of the piston and catch piston engage.