Ball-hinged transmission shaft with straight shaft

A ball-hinged transmission shaft, comprising:

• a socket,
• a ball, and
• a straight shaft,
• wherein an outer spherical surface of the ball is positioned and limited in an inner positioning spherical surface of the socket to form a sliding fit pair;
• a transmission hole is formed in the ball;
• after passing through the transmission hole of the ball, the straight shaft is hinged into a bearing hole of the socket through a bearing;
• a rolling element is further coaxially provided on the straight shaft, the rolling element is a rotator with an axis of the straight shaft as a center of rotation, an outside of the rolling element is connected to the bearing;
• a mouth-shaped surface is further provided at two ends of the transmission hole of the ball, the mouth-shaped surface is a curved surface matching a shape of the rolling element, the rolling element is fit and provided in the mouth-shaped surface at the two ends of the transmission hole of the ball;
• and
• the ball is restricted by the inner positioning spherical surface of the socket, the straight shaft, and the rolling element at the same time.