Ball joint structure and manufacturing method thereof

A manufacturing method of a ball joint, comprising:

• 1) mounting a first bearing on a ball formed at one end of a ball stud so as to cover a portion of the ball, comprising:
• mounting said first bearing with a first stepped part formed at an upper end thereof on a lower portion of the ball of the ball stud;
• and
• coupling the first stepped part with a second stepped part of a second bearing by placing the second bearing with the second stepped part corresponding to the first stepped part at a lower end thereof onto the ball;
• 2) disposing the ball in a mold, said ball space from the mold by a preset distance;
• 3) insert-molding a ball housing and a socket, or a socket in the space, between the bearing and the mold;
• 4) disposing a metal reinforcement between the bearing and the mold;
• and
• 5) insert-molding the ball housing between the bearing and the metal reinforcement;
• wherein an interior surface of the metal reinforcement is knurled, and the first bearing and the second bearing have protrusions and depressions formed at an outer circumferential surface thereof so as to strengthen adhesive force when insert-molding the ball housing.

A ball joint structure comprising:

• a ball stud having a ball formed at one end thereof;
• a bearing comprising a first bearing coupled to the ball for an interior surface thereof to slide on an exterior surface of the ball and covering an exterior surface of one side of the ball, and a second bearing coupled to the ball for an interior surface thereof to slide on the exterior surface of the ball and covering an exterior surface of the other side of the ball;
• a ball housing integrally insert-molded with the bearing so as to cover the outside of the bearing;
• a metal reinforcement provided at an exterior surface of the ball housing or in the ball housing and covering the bearing;
• a flowing hole formed at the metal reinforcement;
• a knurling portion formed at an interior circumference or an exterior surface of the metal reinforcement;
• a bushing housing distanced from the ball housing and connected to a vehicle body;
• and
• an arm connecting the ball housing with the bushing housing,
• wherein the flowing hole and the knurling portion strengthen adhesive force when inset-molding the ball housing.