A shock absorber for a wheel suspension of a vehicle may include an outer cylinder, an outer piston that is axially displaceably guided in the outer cylinder, an inner piston that is axially displaceably guided in the outer piston, and a piston rod that is connected to the inner piston and that is guided out of the outer piston. A surface, which is located remote from the piston rod, of a piston portion of the outer piston, which is axially displaceably guided on an inner lateral surface of the outer cylinder, is connected so as to communicate partially with surroundings of the shock absorber.

A shock absorber for a wheel suspension of a vehicle may include an outer cylinder, an outer piston that is axially displaceably guided in the outer cylinder, an inner piston that is axially displaceably guided in the outer piston, and a piston rod that is connected to the inner piston and that is guided out of the outer piston. A surface, which is located remote from the piston rod, of a piston portion of the outer piston, which is axially displaceably guided on an inner lateral surface of the outer cylinder, is connected so as to communicate partially with surroundings of the shock absorber.

Methods and systems for hydraulic vehicle suspension are provided. A hydraulic suspension system, in one example, includes a first manifold including a piston-side interface and a rod-side interface fluidically coupled to a piston chamber and a rod chamber, respectively, for each of a first hydraulic cylinder and a second hydraulic cylinder. In the system, the first manifold includes a first electrically activated valve fluidically coupled to the piston-side interfaces, a first damping device, and a second damping device, the first electrically activated valve is configured to lock and unlock vertical motion of the first and second hydraulic cylinders and, while vertical motion of the first and second hydraulic cylinders is locked, the first electrically activated valve permits fluidic communication between the first and second hydraulic cylinders to permit free roll motion in the hydraulic suspension system.

A control system includes: a target volume module configured to determine a target volume of hydraulic fluid within a suspension system of a vehicle based on a target pressure of the hydraulic fluid within the suspension system; a volume command module configured to generate a volume command based on the target volume and a present volume of the hydraulic fluid within first and second circuits; a command module configured to, based on the volume command, generate: a pump command for an electric hydraulic fluid pump; and first and second valve commands for first and second seat valves that regulate hydraulic fluid flow to and from the first and second circuits, respectively; a valve control module that actuates the first and second seat valves based on the first and second valve commands, respectively; and a pump control module that controls operation of the pump based on the pump command.

A suspension system for a vehicle is provided. The system utilizes pistons, one on each side of the vehicle, engaged with a vehicle body at a distal end and having a fluid chamber at the proximal end. The system further has a central chamber having a rod freely laterally moving therein. A fluid communicates between the central chamber and each piston fluid chamber. Upon nonlinear forces applied to the vehicle, the rod is urged in one direction or another. This urging applies force to the fluid in the central chamber, and in turn, to the piston in the corresponding side of the vehicle, urging the piston up and in turn urging the vehicle body up.

An apparatus for actively controlling stability of a vehicle is provided. The apparatus includes a strut tower brace bar that is disposed in a lateral direction of a vehicle body and opposite ends of the strut tower brace bar are individually connected to upper portions of left and right shock absorbers. Additionally, an actuator is disposed at a predetermined position in a longitudinal direction of the strut tower brace bar. When torsional deformation of the strut tower brace bar occurs due to rolling of the vehicle body, the actuator is configured to restore the strut tower brace bar by receiving gas from the left and right shock absorbers.

A damping force change mechanism includes an on-off valve located in a through hole of a piston rod. The on-off valve opens/closes a third hydraulic oil passage that allows a first oil chamber on a free piston side and a second oil chamber between a first piston and a second piston to communicate with each other. The on-off valve includes an expanded diameter portion in the first oil chamber extending outward in the radial direction. The expanded diameter portion faces the entire opening edge of the through hole and tightly contacts an end surface of the piston rod. The magnitude of a damping force is easily changed, and a damping force characteristic in a case in which the damping force is large is stabilized.

A damping force change mechanism includes an on-off valve located in a through hole of a piston rod. The on-off valve opens/closes a third hydraulic oil passage that allows a first oil chamber on a free piston side and a second oil chamber between a first piston and a second piston to communicate with each other. The on-off valve includes an expanded diameter portion in the first oil chamber extending outward in the radial direction. The expanded diameter portion faces the entire opening edge of the through hole and tightly contacts an end surface of the piston rod. The magnitude of a damping force is easily changed, and a damping force characteristic in a case in which the damping force is large is stabilized.

A damper assembly includes an outer cylinder, an inner cylinder positioned at least partially within the outer cylinder, a cap coupled to the inner cylinder, and a plunger positioned radially inward from the inner cylinder and coupled to a rod. The plunger, the cap, and an interior of the inner cylinder at least partially define a first chamber. The suspension system further includes a passage extending through the rod and fluidly coupled with the first chamber, a piston coupled to the inner cylinder and extending radially outward toward the outer cylinder, a first port in fluid communication with the plunger, the cap, and the inner cylinder through the passage, and a second port in fluid communication with the piston, the inner cylinder, and the outer cylinder. The piston, an exterior surface of the inner cylinder, and the outer cylinder at least partially define a second chamber.

A damper assembly includes an outer cylinder, an inner cylinder positioned at least partially within the outer cylinder, a cap coupled to the inner cylinder, and a plunger positioned radially inward from the inner cylinder and coupled to a rod. The plunger, the cap, and an interior of the inner cylinder at least partially define a first chamber. The suspension system further includes a passage extending through the rod and fluidly coupled with the first chamber, a piston coupled to the inner cylinder and extending radially outward toward the outer cylinder, a first port in fluid communication with the plunger, the cap, and the inner cylinder through the passage, and a second port in fluid communication with the piston, the inner cylinder, and the outer cylinder. The piston, an exterior surface of the inner cylinder, and the outer cylinder at least partially define a second chamber.