US Patent 7510344 Joint structure of ball joint and arm

The invention is a joint structure of a ball joint and an arm, which includes: a ball stud having a spherical ball part and a shank part extending from the spherical ball part; a bearing cupping the spherical ball part of the ball stud; a housing holding the bearing therein; and an arm having a hole into which the housing is inserted. The housing has a circumferential groove in an outer-circumference surface thereof. The housing is adapted to be pressed into the hole of the arm. The groove functions to weaken a load by the arm after the housing is pressed into the hole of the arm. Thus, a pressure to the spherical ball part of the ball stud is inhibited so that a sliding characteristic of the ball stud is improved.