Abstract: A ball joint is disclosed having a socket, a ball received by the socket and a stud extending outwardly from the ball. A ball seat member is received in the socket and has a soft portion with an inner spherical surface which covers the portion of the ball at the side opposite to the stud. The soft portion is axially compressed by a cap closing an opening in the socket opposite to the stud, while expanding radially outward to be penetrated by linear projections formed in a hard portion of the ball seat member. Further, a gap remains between the soft portion after it has expanded radially outwardly and the inner cylindrical surface of the hard portion of the ball seat member so that the soft portion of the ball seat member contacts the hard portion of the ball seat member only at the linear projections.

Abstract: A hydraulic valve lifter is held in the recess of the rocker arm swingably pivoted to the rocker shaft. An oil pressure chamber is formed between the lifter body and the plunger. An oil chamber to supply the oil to the oil pressure chamber is formed between the plunger and the recess. An oil supply path to supply the oil through the oil path of the rocker shaft communicates to the oil chamber. A return path is provided extending from the top of the oil chamber to a clearance between the inside of the rocker arm hole and the outside of the rocker shaft or to a clearance between the outside of the lifter body and the inside of the rocker arm recess. With this arrangement of the device, the air infiltrating the oil chamber can be discharged from the top of the oil chamber via the return path and the clearance, thereby preventing invasion of the air into the oil pressure chamber and ensuring normal functioning of the hydraulic valve lifter.