Dust cover for ball joint

A dust cover configured for use with a ball joint that includes a ball stud having a spherical head portion and a shaft, a socket, and a knuckle, the spherical head portion of the ball stud being retained within the socket, and the shaft of the ball stud being fixed to the knuckle, the knuckle including a notch portion, and an annular step portion that is provided on an inner peripheral surface of the knuckle, the dust cover comprising:

• a first end large-diameter opening portion that is configured to be fixed and retained to an outer peripheral surface of the socket;
• a second end small-diameter opening portion that is configured to be retained to an outer peripheral surface of the shaft;
• and
• a plate member that is separate and apart from the second end small-diameter opening portion, and that is at least partially positioned between the inner peripheral surface of the knuckle located at a second end small-diameter opening portion side of the knuckle and the outer peripheral surface of the shaft,
• wherein the plate member includes an annular plate member that is made of a hard material, an annular seal portion that is integrally formed on an inner peripheral side of the annular plate member and is made of a rubber-like elastic material, and an engagement projection which is provided on the annular seal portion, engages with the notch portion of the knuckle, and is made of a rubber-like elastic material, and
• wherein the annular seal portion is configured to be compressed between the annular step portion of the knuckle and the outer peripheral surface of the shaft.