About spring properties

Spring properties are one of the features of bellows. Spring properties determine a good part of product shape. Terminology related to the spring properties are shown.

About spring properties

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Name	Description
Axial direction spring constant	Load required for 1mm displacement in an axial direction, showing an almost constant value load elasticity regions, while changing when the pulling force tends toward plastic deformation with a large displacement or where corrugations interfere near adhesion; mostly used in an almost constant range, while being used under interference depending on specification conditions. (On bellows, the axial direction spring constant decreases in the following cases: small thickness, large span, many threads, etc.)
Perpendicular-to-an-axis direction spring constant	Load required for 1mm displacement in a perpendicular-to-an-axis direction, decreasing with increasing face-to-face dimension in proportion to the axial direction spring constant.
Meandering and buckling	Flexion of bellows by application of a contraction side force from internal pressure or unrestricted length. The pressure at which buckling occurs varies according to the spring constant, bellows length, etc. Meandering --- The deformation, which is apparent curvedness, is restored by removing the load. Buckling --- The deformation, which is advanced meandering, is not restored even when the load is removed. Normally, a design is made in a buckling-free range, but if it cannot be absorbed by one block, support is provided by intermediate fittings as another multiblock structure.
Natural frequency	Bellows also have a natural frequency that is detected when subjected to free vibration. If a resonance phenomenon occurs, an unpredictable load is applied to the bellows, which can cause premature damage.