A method for assembling a constant velocity joint includes a first step of inserting a unit in which balls are housed in windows of a cage from one side in a direction of a central axis of an outer joint member toward another side in the direction of the central axis of the outer joint member to allow the balls to roll along outer ball grooves; and a second step of mounting an inner joint member while moving the inner joint member in the outer joint member along the direction of the central axis of the outer joint member.

A method for assembling a constant velocity joint includes a first step of inserting a unit in which balls are housed in windows of a cage from one side in a direction of a central axis of an outer joint member toward another side in the direction of the central axis of the outer joint member to allow the balls to roll along outer ball grooves; and a second step of mounting an inner joint member while moving the inner joint member in the outer joint member along the direction of the central axis of the outer joint member.

In a constant velocity joint, each of outer ball grooves includes a finished portion, and a finishing relief portion adjoining the finished portion in a direction of a central axis of an outer joint member. An inner ball groove and the finishing relief portion have a relationship in which an action direction of an inner ball groove-side pressing force with which a ball is pressed by the inner ball groove at an inner ball groove-side contact point where the inner ball groove contacts the ball along with movement of the inner joint member is offset toward the finished portion from an action direction of an outer ball groove-side pressing force with which the ball is pressed by the finishing relief portion at an outer ball groove-side contact point where the finishing relief portion contacts the ball along with the movement of the inner joint member.

In a fixed type constant velocity universal joint, an axial offset amount of a curvature center of each of track grooves of outer and inner joint members is set to 0. The track grooves of the outer and inner joint members are each inclined with respect to an axis line. The track grooves adjacent to each other in a circumferential direction are inclined in opposite directions. The track grooves of the outer and inner joint members that are opposed to each other are inclined with respect to the axis line in opposite directions. A chamfered portion is formed on a track inlet end of each of the track grooves of the outer joint member. When the cage and the inner joint member are inclined with respect to the outer joint member, balls are incorporated into two cage windows at the same time through the chamfered portions.

In a fixed type constant velocity universal joint, an axial offset amount of a curvature center of each of track grooves of outer and inner joint members is set to 0. The track grooves of the outer and inner joint members are each inclined with respect to an axis line. The track grooves adjacent to each other in a circumferential direction are inclined in opposite directions. The track grooves of the outer and inner joint members that are opposed to each other are inclined with respect to the axis line in opposite directions. A chamfered portion is formed on a track inlet end of each of the track grooves of the outer joint member. When the cage and the inner joint member are inclined with respect to the outer joint member, balls are incorporated into two cage windows at the same time through the chamfered portions.

A method is provided for manufacturing an outer ring of a constant velocity joint including an outer ring, an inner rotational member, a torque-transmitting rolling element, and a defining member. The outer ring includes: a first inner peripheral surface to which the defining member is attached; a second inner peripheral surface; and protrusions protruding radially inward of the first inner surface and the second inner peripheral surface so as to restrict axial movement of the inner rotational member and the rolling element. The manufacturing method includes: a plastic working step involving providing a base member; and a bottom removing step involving partially removing a bottom of the base member so as to form a through hole. The plastic working step further involves providing the second inner peripheral surface. The bottom removing step further involves providing the protrusions.

A method is provided for manufacturing an outer ring of a constant velocity joint including an outer ring, an inner rotational member, a torque-transmitting rolling element, and a defining member. The outer ring includes: a first inner peripheral surface to which the defining member is attached; a second inner peripheral surface; and protrusions protruding radially inward of the first inner surface and the second inner peripheral surface so as to restrict axial movement of the inner rotational member and the rolling element. The manufacturing method includes: a plastic working step involving providing a base member; and a bottom removing step involving partially removing a bottom of the base member so as to form a through hole. The plastic working step further involves providing the second inner peripheral surface. The bottom removing step further involves providing the protrusions.

A plunging type constant velocity universal joint 1 for a propeller shaft includes an outer joint member 2, an inner joint member 3, eight torque transmitting balls 4, and a cage 5. A center of curvature O1 of a spherical outer surface 12 and a center of curvature O2 of a spherical inner surface 13 of the cage 5 each have an equal and axially opposite offset (f) with respect to a center O3 of pockets 5a. A ratio f/PCD.sub.BALL between the offset (f) of the cage 5 and a pitch circle diameter (PCD.sub.BALL) of the torque transmitting balls 4 is 0.07 or more and 0.09 or less.

A plunging type constant velocity universal joint 1 for a propeller shaft includes an outer joint member 2, an inner joint member 3, eight torque transmitting balls 4, and a cage 5. A center of curvature O1 of a spherical outer surface 12 and a center of curvature O2 of a spherical inner surface 13 of the cage 5 each have an equal and axially opposite offset (f) with respect to a center O3 of pockets 5a. A ratio f/PCD.sub.BALL between the offset (f) of the cage 5 and a pitch circle diameter (PCD.sub.BALL) of the torque transmitting balls 4 is 0.07 or more and 0.09 or less.

A ball cage for universal use both in a cross-groove type plunging constant velocity joint and in a cross-groove type fixed constant velocity joint has an external contour with sections of different curvature. Axial edge sections of the external contour are designed as spherical sections located on the circumference of an imaginary sphere, whereas a center section of the external contour located axially between the edge sections runs radially inside the diameter of the imaginary sphere.