| 摘要 |
PROBLEM TO BE SOLVED: To move the outer surface of a ball part freely in a condition of slide engagement with the inner surface of a bearing member by selecting the first and second plastic materials so as to be incompatible with each other. SOLUTION: This manufacturing method of a ball joint 10 includes a process providing a stud 20 having a head part 24 and a shank part 26. The first polymer material is formed at the head part 24 of the stud 20, and a ball part 60 made of the first polymer material is formed on the stud. The ball part has a spherical outer surface 62. The second polymer material is formed on the spherical outer surface 62 of the ball part 60 to form a bearing 100 of the second polymer material. The bearing encloses the ball part of the stud. The second polymer material is incompatible with the first polymer material, therefore the second polymeric material is not combined with the first polymer material either during or after forming the second polymer material. The ball part 60 and the bearing 100 are positioned in a socket 90 in such a condition that the stud 20 protrudes from the socket, thus forming a ball joint. |
