Abstract: During the assembly steps of a rotary valve, after an input shaft is attached onto a torsion bar, the input shaft is rotated clockwise and counterclockwise concentrically with the torsion bar. A central position is thus detected and determined such that a hydraulic pressure, which is generated when the input shaft is rotated by some angle clockwise from the central position relative to an output shaft, is symmetrical with a hydraulic pressure generated when the input shaft is rotated by the same angle counterclockwise from the central position. While the determined central position of the input shaft in a peripheral direction relative to the torsion bar is maintained, the input shaft is axially secured. By pulling the torsion bar further into the input shaft, an engaging portion of the torsion bar engages in a securing bore of the input shaft.

Abstract: A method of manufacturing a ball joint serves to reduce the cost for producing the joint. In the method, while a ball portion of a ball stud of the ball joint is being placed in a mold, a socket is cast-molded in such a manner that the socket will form an integral structure surrounding the ball portion. Thereafter, force is applied to the outer wall of the socket by means of a plurality of mill rolls in such a manner that the force causes deformation of the socket so as to allow the ball portion of the ball stud to be slidably rotated relative to the socket.