Abstract
A vacuum bellows assembly that can follow a twisted displacement around the axis is newly developed. It consists of 36 convolutions with a core whose inner circle is eccentric to the outer one. The deformation of the bellows is analyzed by means of a finite element method (FEM), while a torsional moment is applied to the bellows. From the analytical result, it is explained that the new bellows can be twisted much easier than a traditional bellows. Besides, it is experimentally shown that the newly developed bellows with a total length of 86 mm, an inner diameter of 40 mm and an outer diameter of 70 mm is able to be twisted quite smoothly up to about 5°.
