Constant velocity joint

A constant-velocity rotary joint for torque transmission, comprising:

• an outer joint portion with several outer ball tracks,
• an inner joint portion with several inner ball tracks, torque-transmitting balls, which are each guided in track pairs of outer ball tracks and inner ball tracks, and
• a cage, which accommodates the torque-transmitting balls in circumferentially distributed cage windows and retains them in a common joint center plane when the constant-velocity rotary joint is straight,
• wherein the outer joint portion has a longitudinal axis and, situated axially opposite each other, an opening side and a connecting part, and paths of the centers of the torque-transmitting balls is in each case defined as a center line of the respective ball track, and
• a first type of track pairs of ball tracks is configured so that the centers of curvature of the center lines of the ball tracks are situated in the joint center plane when the joint is straight,
• while a second type of track pairs of ball tracks is configured so that their center lines have at least two portions, and the respective center line of the outer ball tracks of the second type of track pairs has at least one inner portion and one outer portion, wherein the inner portion is situated on a connection side of the outer joint portion, while the outer portion is situated on an opening side of the outer joint portion, and the inner portion is curved and a center of curvature of the inner portion, when the joint is straight, is situated within a hollow volume of the outer joint portion, offset from the joint center plane towards the opening side, while the center line of the outer ball tracks of the second type of track pairs widens through the outer portion towards the opening side.