Ball type constant velocity joint

A ball-type constant velocity joint comprising:

• an inner race comprising a plurality of first outer circumferential grooves formed therein;
• an inner cage race comprising a plurality of second outer circumferential grooves and a plurality of first slots formed therein, the inner cage race surrounding the inner race;
• a middle cage race comprising a plurality of first inner circumferential grooves, a plurality of third outer circumferential grooves, and a plurality of second slots formed therein, the middle cage race surrounding the inner cage race;
• an outer cage race comprising a plurality of second inner circumferential grooves and a plurality of third slots formed therein, the outer cage race surrounding the middle cage race;
• an outer race comprising a plurality of third inner circumferential grooves formed therein, the outer race surrounding the outer cage race;
• a plurality of first balls respectively interposed between the plurality of first outer circumferential grooves and the plurality of first inner circumferential grooves to be constrained by the plurality of first slots;
• a plurality of second balls respectively interposed between the plurality of second outer circumferential grooves and the plurality of second inner circumferential grooves to be constrained by the plurality of second slots;
• and
• a plurality of third balls respectively interposed between the plurality of third outer circumferential grooves and the plurality of third inner circumferential grooves to be constrained by the plurality of third slots,
• wherein each of the plurality of grooves is formed to have an arc-shaped bottom surface when viewed in longitudinal-section of the constant velocity joint.

A ball-type constant velocity joint comprising:

• an inner race comprising a plurality of first outer circumferential grooves formed therein;
• an inner cage race comprising a plurality of second outer circumferential grooves and a plurality of first slots formed therein, the inner cage race surrounding the inner race;
• a middle cage race comprising a plurality of first inner circumferential grooves, a plurality of third outer circumferential grooves, and a plurality of second slots formed therein, the middle cage race surrounding the inner cage race;
• an outer cage race comprising a plurality of second inner circumferential grooves and a plurality of third slots formed therein, the outer cage race surrounding the middle cage race;
• an outer race comprising a plurality of third inner circumferential grooves formed therein, the outer race surrounding the outer cage race;
• a plurality of first balls respectively interposed between the plurality of first outer circumferential grooves and the plurality of first inner circumferential grooves to be constrained by the plurality of first slots;
• a plurality of second balls respectively interposed between the plurality of second outer circumferential grooves and the plurality of second inner circumferential grooves to be constrained by the plurality of second slots;
• and
• a plurality of third balls respectively interposed between the plurality of third outer circumferential grooves and the plurality of third inner circumferential grooves to be constrained by the plurality of third slots,
• wherein each pair of grooves among the plurality of grooves forming a track for a respective one of the plurality of balls is inclined in opposite directions by a predetermined angle with respect to a central axis of the constant velocity joint so as to be skewed with respect to each other.

A ball-type constant velocity joint comprising:

• an inner race comprising a plurality of first outer circumferential grooves formed therein;
• an inner cage race comprising a plurality of second outer circumferential grooves and a plurality of first slots formed therein, the inner cage race surrounding the inner race;
• a middle cage race comprising a plurality of first inner circumferential grooves, a plurality of third outer circumferential grooves, and a plurality of second slots formed therein, the middle cage race surrounding the inner cage race;
• an outer cage race comprising a plurality of second inner circumferential grooves and a plurality of third slots formed therein, the outer cage race surrounding the middle cage race;
• an outer race comprising a plurality of third inner circumferential grooves formed therein, the outer race surrounding the outer cage race;
• a plurality of first balls respectively interposed between the plurality of first outer circumferential grooves and the plurality of first inner circumferential grooves to be constrained by the plurality of first slots;
• a plurality of second balls respectively interposed between the plurality of second outer circumferential grooves and the plurality of second inner circumferential grooves to be constrained by the plurality of second slots;
• and
• a plurality of third balls respectively interposed between the plurality of third outer circumferential grooves and the plurality of third inner circumferential grooves to be constrained by the plurality of third slots,
• wherein, among the plurality of grooves formed in the inner race and the middle cage race, each pair of grooves forming a track for a respective one of the plurality of first balls is inclined in opposite directions by a predetermined angle with respect to a central axis of the constant velocity joint,
• wherein, among the plurality of grooves formed in the middle cage race and the outer race, each pair of grooves forming a track for a respective one of the plurality of third balls is inclined in opposite directions by a predetermined angle with respect to the central axis of the constant velocity joint, and
• wherein, among the plurality of grooves formed in the inner cage race and the outer cage race, each pair of grooves forming a track for a respective one of the plurality of second balls is formed parallel to each other.