The development of pivot bearing with multiple degrees of freedom: 1st report: Prototype of pivot bearing with two degrees of freedom

This paper deals with the prototype of a new pivot bearing having two degrees of freedom. The idea of the pivot bearing is based on a continuous velocity joint (CVJ). The experimental axial stiffness and contact pressure are compared with those determined by theoretical analysis. Then, it is confirmed that the pivot bearing swings smoothly with a range of ±25°. Furthermore, the stiffness of the bearing increases as the swinging angle becomes larger. Therefore, this newly developed pivot bearing may be applied to a parallel mechanism, a joint of robot and so on.     

The development of pivot bearing with multiple degrees of freedom: 2nd Report: Prototype of pivot bearing with three degrees of freedom

In this paper, we report a prototype of a new pivot bearing having three degrees of freedom. The idea of the pivot bearing is based on a constant velocity joint (CVJ). In the first report, two types of pivot bearing were designed and produced. Then, the static performance was examined. In this second paper, we have achieved three degrees of freedom by adding a ball bearing mechanism. However, this bearing with three degrees of freedom was larger than the bearing with two degrees of freedom. Then, in order to improve the internal structure, a full complement ball bearing was applied. Thus, the size of the bearing with three degrees of freedom was conformed to the bearing with two degrees of freedom. Furthermore, process accuracy was evaluated.