Fichtel & Sachs Ag

Hans Reimer

Manfred Grundei

Alfred Wirth

Klaus Mackert

Franz Diehl

Harald Holzapfel

Klaus Splett

A piston-cylinder aggregate comprising a cylinder in which an axially movable piston rod is arranged is provided. The piston rod has two pistons, which are separated from each other and which produce a damping force of a variable magnitude depending on the piston rod's stroke position. The piston-cylinder aggregate has a bypass area defined in its inner wall along a portion of the length of the cylinder, so that the damping force is at least reduced in the stroke area of the bypass, and the two pistons have a separation equal to or less than the length of the bypass, such that depending on the position of the piston rod, a damping force of variable magnitude is produced. For example, when both pistons are disposed within a section of the cylinder defined by the bypass area, the dampening force exerted by the piston rod is minimized, while when both pistons are outside the bypass area, the dampening force in both stroke directions is maximized.

Piston-cylinder aggregate with displacement-dependent dampening force

Vibration damper, the piston valve of which is fastened to a piston rod, and which comprises a piston body with fluid passage channels which are covered by valve discs on support bodies with valve support surfaces, whereby the piston divides a cylinder tube into two work chambers by way of at least one piston ring, characterized by the fact that the piston body is realized in a disc shape, in one piece, and by way of stamping.

Shock absorber for a motor vehicle, which shock absorber has a piston

According to an illustrative example of this invention, the piston of a hydraulic oscillation damper is provided with a traction valve, i.e. a valve which is intended to damp the outward movement of the piston rod. This traction valve includes two valve discs and a valve member. The valve member is biased towards a closed position and urges the valve discs against a valve face of the piston. In response to a predetermined pressure difference between the two working chambers on both sides of the piston, a flow passage is opened by lifting the valve discs and the valve member from the valve face. Below said predetermined pressure difference, a preliminary restricted flow passage exists. This preliminary restricted flow passage extends in series across the radially inner circumferential edge of a first valve disc adjacent to the piston and through radially inner edge recesses and through radially outer edge recesses of a second valve disc adjacent to the first valve disc. A first liquid flow resistance is established by the radially inner edge recesses, and a second liquid flow resistance is established by the radially outer edge recesses. The first liquid flow resistance is larger than the second flow resistance. Between respective radially inner edge recesses and respective radially outer edge recesses of the second valve disc, circumferential flow paths are established by a circumferential groove within the valve member. These circumferential flow paths act as tranquillizing paths.

Damping valve unit for a hydraulic oscillation damper

A pressure accumulator for a hydraulic system includes a rigid container whose cavity contains a partition of pliable, resilient material which seals one compartment adjacent the bottom wall of the container from another compartment containing a gas under a pressure sufficient for expanding the partition into abutting engagement with the bottom wall when the fluid pressure in the one compartment equals atmospheric pressure. A passage outward from the one compartment through the bottom wall is shielded against insertion therein of any portion of the partition, and the resulting risk of injury to the partition, by a shielding member projecting from the bottom wall into the one compartment and having a frontal surface directed toward the other compartment. Its annular rim portion has a surface contiguously adjacent an annular portion of the bottom wall, and the two annular surface portions and the partition bound therebetween an annular space at atmospheric pressure in the one compartment. The passage of the bottom wall communicates with an orifice in the annular space.

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Waigolshausen, Germany

Hans Reimer