Patent ID: 7517284

Claim:
A joint section between a shaft and universal-joint yoke comprising: a shaft that rotates when in operation; a pair of supported surfaces that are formed on opposite side surfaces on a tip end of the shaft; a yoke constituting a universal joint that has a base end section with an opening on one side; a pair of support-plate sections of the base end section that are located on opposite sides of a center axis of the yoke so that they are separated from one another, inside surfaces of the support-plate sections functioning as support surfaces and facing the supported surfaces; a connecting section of the base end section that connects the support-plate sections at a location opposite to the opening; holes that are concentric with one another and are formed in the support-plate sections, respectively, adjacent to the opening; and a support bolt that extends between the support-plate sections in the holes and is adapted to be connected to threads at a tip end of the support bolt to draw the support-plate sections toward one another; and wherein the joint section is constructed so that before the support bolt is connected to the threads, a clearance is formed between the support surfaces and the supported surfaces, and after the support bolt is connected to the threads, a tip surface on the tip end of the shaft located between the supported surfaces faces an inside surface of the connecting section and comes into contact with the inside surface of the connecting section of the yoke at two contact locations, and a clearance between the tip surface and the inside surface is formed between the two contact locations, whereby the tip surface on the tip end of the shaft is made to fit with the inside surface of the connecting section such that it is not possible for the tip end of the shaft to move in opposite directions with respect to the support-plate sections, and such that a center axis of the shaft does not move in a direction orthogonal to this center axis, and the tip end of the shaft does not rotate around the center axis.