A constant velocity joint is provided with at least a pair of tracks whose geometry is defined based on ball path that follows a parametric equation and the parametric function is in the form of a polynomial displacement function of a fourth order or larger.

A constant velocity joint is provided with at least a pair of tracks whose geometry is defined based on ball path that follows a parametric equation and the parametric function is in the form of a polynomial displacement function of a fourth order or larger.

A constant velocity universal joint includes a body which encloses the constant velocity joint components and provides a smooth outer surface. A semi-rigid plastic boot has a spherical surface sized to generally match the outer surface of the body. The material of the boot is sufficiently elastic to allow the boot to fit over the body, yet sufficiently resilient to snap the open end closed after the boot is placed over the body to provide a substantial seal preventing entry of debris under the seal. A retaining ring is positioned on the boot near the truncated end, the ring establishing the location of an elastic seal that contacts the outer surface of the body.

A constant velocity universal joint includes a body which encloses the constant velocity joint components and provides a smooth outer surface. A semi-rigid plastic boot has a spherical surface sized to generally match the outer surface of the body. The material of the boot is sufficiently elastic to allow the boot to fit over the body, yet sufficiently resilient to snap the open end closed after the boot is placed over the body to provide a substantial seal preventing entry of debris under the seal. A retaining ring is positioned on the boot near the truncated end, the ring establishing the location of an elastic seal that contacts the outer surface of the body.

A constant-velocity rotary joint includes an outer joint portion with outer ball tracks, an inner joint portion with inner ball tracks, balls guided in a track pair formed by one outer ball track and one inner ball track, and a cage with windows to accommodate and retain the balls. Each outer ball track has an outer ball track center line. Each inner ball track has an inner ball track center line. When the constant-velocity rotary joint is straight, the inner ball track center line and the outer ball track center line of the track pair intersect in an intersection point and are not mirror-symmetrical with respect to a mirror plane through the intersection point, and the inner portion of the inner ball track center line widens more, with respect to a longitudinal axis of the outer joint portion, than the outer portion of the outer ball track center line.

A constant velocity universal joint includes outer and inner joint members that transmit torque while allowing angular displacement via balls, a power transmission shaft connected to the inner joint member in a torque transmittable manner, and a detachable mechanism between the inner joint member and the power transmission shaft to detach the power transmission shaft from the inner joint member. The detachable mechanism includes a cylindrical member externally fit onto the power transmission shaft, spheres movable in a radial direction in the cylindrical member, and an annular member movable in an axial direction on an outer periphery of the cylindrical member. Locking claws are provided at an end of an inner joint member side of the annular member, and a locking groove is provided at an end of an annular member side of the inner joint member. The locking claws are fitted into the locking groove.

A constant velocity universal joint includes an inner ring and an outer ring. A cage is disposed between an outer spherical surface of the inner ring and an inner spherical surface of the outer ring, and has windows in which respective balls are received. The cage has ball contact surface areas with which the balls come into contact, and includes soft portions that are lower in hardness than the ball contact surface areas. The soft portions are formed by local heat treatment at portions of the windows that are kept out of contact with the balls or surface portions around the windows.

A constant velocity universal joint includes outer and inner joint members configured to transmit torque therebetween through intermediation of balls while allowing angular displacement. A power transmission shaft is coupled to the inner joint member. A mounting and dismounting mechanism configured to mount and dismount the power transmission shaft to and from the inner joint member is provided between the inner joint member and the power transmission shaft. The mounting and dismounting mechanism includes a tubular member inserted externally on the power transmission shaft so as to extend from the inner joint member, a fixing member received in the tubular member, and an annular member arranged on an outer periphery of the tubular member. The fixing member is moved in the radial direction along with movement of the annular member in the axial direction so that the fixing member is mountable to and dismountable from the power transmission shaft.

A constant velocity universal joint includes outer and inner joint members configured to transmit torque therebetween through intermediation of balls while allowing angular displacement. A power transmission shaft is coupled to the inner joint member. A mounting and dismounting mechanism configured to mount and dismount the power transmission shaft to and from the inner joint member is provided between the inner joint member and the power transmission shaft. The mounting and dismounting mechanism includes a tubular member inserted externally on the power transmission shaft so as to extend from the inner joint member, a fixing member received in the tubular member, and an annular member arranged on an outer periphery of the tubular member. The fixing member is moved in the radial direction along with movement of the annular member in the axial direction so that the fixing member is mountable to and dismountable from the power transmission shaft.

A speed-reducing or -increasing apparatus, with first and second crown gears facing one another, with a cam unit that causes the first crown gear to incline with respect to the second crown gear so that the first crown gear meshes with the second crown gear, that causes the first crown gear to precess in such a manner as to move the meshing position, and couples to an input or output shaft. A rolling element is between the cam unit and the first crown gear, and the cam unit includes a first member that couples to the input or output shaft and a second member made of steel and including a rolling element rolling portion where the rolling element rolls, the second member configured to be incapable of rotating relatively to the first member, and at least part of the first member having a lower specific gravity than the second member.