A center biased actuator having an outer cylinder, a slave cylinder linearly transposed within the outer cylinder, a rod assembly with a piston linearly transposed within the slave cylinder and a rod extending from the outer cylinder, one or more first dynamic seals arranged to act on a sidewall of the rod to inhibit hydraulic fluid leaking from the outer cylinder, one or more second dynamic seals arranged to act on a sidewall of the slave cylinder or an inner surface of the outer cylinder to inhibit hydraulic fluid leaking from the outer cylinder, and a gas chamber comprising a sealed expandable chamber containing gas. The expandable chamber is arranged to act on hydraulic fluid within the center biased actuator to bias the center biased actuator to assume an intermediate condition which lies between a compressed condition and an extended condition.

A rotary damper assembly comprises a housing extending along a center axis. The housing includes an upper portion and a lower portion. The lower portion defines a fluid chamber. The upper portion defines a compartment in communication with the fluid chamber. The magnetic field generator includes a magnetic core located between the upper portion and the lower portion. The magnetic core extends along the center axis between the upper portion and the lower portion. At least one coil extends about the magnetic core. A shaft extends along the center axis through the upper portion and the magnetic core and into the fluid chamber to facilitate magnetorheological fluid flow from the compartment to the fluid chamber. The magnetic field generator includes an insert, containing a permanent magnetic material, for generating a permanent magnetic field to change viscosity of the magnetorheological fluid.

Provided is a gas strut, including: an outer working space arranged radially to the stroke axis between the working cylinder and the equalizing cylinder, the outer working space being connected to the inner working space in a gas-conducting manner; an equalizing piston enclosing the working cylinder radially to the stroke axis, the equalizing piston) being mounted displaceably along the stroke axis, delimiting the outer working space on one side transversely to the stroke axis and being subjected to a pressure of the working medium and a pressure of the equalizing medium so as to increase the volume of the outer working space; and a restoring medium arranged in a restoring space radially to the stroke axis between the working cylinder and the equalizing cylinder, the equalizing piston being subjected to a pressure of the restoring medium so as to decrease the volume of the outer working space.

A gas pressure spring is provided including a working cylinder which, together with a slidably mounted compensating piston, encloses a working chamber filled with a working medium. A slidably mounted working piston is fastened to a working rod. In the event of a temperature increase, a compensating medium in a compensating chamber expands. The compensating piston is acted upon by the pressure of the working medium and the pressure of the compensating medium) such that the volume of the working chamber is increased. The temperature dependency of the gas spring force should be reduced by a design which is as simple as possible. For this purpose, the compensating chamber is at least partially surrounded by the working rod. Thus, the compensating medium can be compactly accommodated, and the assembly of the gas spring is simplified.

A temperature compensating valve assembly is provided that includes a bimetallic spring that deforms from a closed position to an open position in response to temperature, and a single-piece valve body having an aperture therethrough and having an open end for receiving the bimetallic spring. The single-piece valve body includes integral retainers for retaining the bimetallic spring in the open end in a location such that the aperture is blocked by the bimetallic spring when in the closed position and is not blocked by the bimetallic spring when in the open position.

Provided is a gas strut, including: an outer working space arranged radially to the stroke axis between the working cylinder and the equalizing cylinder, the outer working space being connected to the inner working space in a gas-conducting manner; an equalizing piston enclosing the working cylinder radially to the stroke axis, the equalizing piston) being mounted displaceably along the stroke axis, delimiting the outer working space on one side transversely to the stroke axis and being subjected to a pressure of the working medium and a pressure of the equalizing medium so as to increase the volume of the outer working space; and a restoring medium arranged in a restoring space radially to the stroke axis between the working cylinder and the equalizing cylinder, the equalizing piston being subjected to a pressure of the restoring medium so as to decrease the volume of the outer working space.

A center biased actuator having an outer cylinder, a slave cylinder linearly transposed within the outer cylinder, a rod assembly with a piston linearly transposed within the slave cylinder and a rod extending from the outer cylinder, one or more first dynamic seals arranged to act on a sidewall of the rod to inhibit hydraulic fluid leaking from the outer cylinder, one or more second dynamic seals arranged to act on a sidewall of the slave cylinder or an inner surface of the outer cylinder to inhibit hydraulic fluid leaking from the outer cylinder, and a gas chamber comprising a sealed expandable chamber containing gas. The expandable chamber is arranged to act on hydraulic fluid within the center biased actuator to bias the center biased actuator to assume an intermediate condition which lies between a compressed condition and an extended condition.

A center biased actuator having an outer cylinder, a slave cylinder linearly transposed within the outer cylinder, a rod assembly with a piston linearly transposed within the slave cylinder and a rod extending from the outer cylinder, one or more first dynamic seals arranged to act on a sidewall of the rod to inhibit hydraulic fluid leaking from the outer cylinder, one or more second dynamic seals arranged to act on a sidewall of the slave cylinder or an inner surface of the outer cylinder to inhibit hydraulic fluid leaking from the outer cylinder, and a gas chamber comprising a sealed expandable chamber containing gas. The expandable chamber is arranged to act on hydraulic fluid within the center biased actuator to bias the center biased actuator to assume an intermediate condition which lies between a compressed condition and an extended condition.

A rotary damper assembly comprises a housing extending along a center axis. The housing includes an upper portion and a lower portion. The lower portion defines a fluid chamber. The upper portion defines a compartment in communication with the fluid chamber. The magnetic field generator includes a magnetic core located between the upper portion and the lower portion. The magnetic core extends along the center axis between the upper portion and the lower portion. At least one coil extends about the magnetic core. A shaft extends along the center axis through the upper portion and the magnetic core and into the fluid chamber to facilitate magnetorheological fluid flow from the compartment to the fluid chamber. The magnetic field generator includes an insert, containing a permanent magnetic material, for generating a permanent magnetic field to change viscosity of the magnetorheological fluid.

A gas pressure spring is provided including an expanding wax as a compensating medium for reducing a temperature dependency of a spring force of the gas pressure spring in an operating temperature range of the gas pressure spring spanning a minimum temperature of 40 C. to +10 C. up to a maximum temperature of +40 C. to +100 C. The expanding wax includes at least one liquid phase and at least one solid phase in the entire operating temperature range, the expanding wax comprising a number of primary alcohols. Also provided is a drive system for a flap including a gas pressure spring for supporting the flap, and an electromechanical drive for driving the flap.