Valve for hydraulic vibration damper - includes ring made of shape memory alloy, so width of choke bore in valve alters when temp. changes occur

摘要

Valve includes an annular gap possessing a cross-section controlled by a ring made of a shape memory alloy, e.g. contg. 55% Ni, 45% Ti. The ring is flat at normal temps., but when it is heated it bulges inwards due to the "memorised deformation", and thus reduces the width of the annular gap through which the hydraulic fluid flows. Redn. in gap width compensates for the redn. in the viscosity of the fluid at elevated temps., so the same damping effect is achieved. When the valve cools, the ring reverts to its initial, flat shape, so the cross-section of the annular gap, i.e. the choke bore, is restored to its initial size.