Abstract
A kind of constant velocity joints of automobile is put into practice by using the symmetry of relative motion of elements in spite that the degree of freedom for a spatial mechanism is zero or negative. The static analysis of these constant velocity joints can not be performed by means of the conventional procedure. In the paper, the degree of freedom of the pair between adjacent elements of the constant velocity joint with driving balls or spherical rollers is made clear. The degree of freedom of the constant velocity joint is calculated for the spatial mechanism obtained by connected the input and output shafts to the frame by lower pairs.
