Described is a rotary coupling that includes a pair of coupling bodies having parallel (preferably coincident) rotation axes, two cylindrical elements and a preload mechanism. A gap is provided between surfaces on the first and second coupling bodies. The first cylindrical element is disposed on the first coupling body and has a first cylinder axis, and the second cylindrical element is disposed on the second coupling body adjacent to the first cylindrical element and has a second cylinder axis that is perpendicular to the first cylinder axis. The preload mechanism imparts a force to each of the first and second coupling bodies and thereby preloads the first and second cylindrical elements against each other at a point of contact. One example of the preload mechanism includes a pair of magnets disposed opposite each other across the gap and another example of the preload mechanism includes an air bearing.

A balancing element for balancing a friction clutch, including a balancing head for providing a balancing mass, and a shaft that is connected to the balancing head, is to be inserted into an opening in the friction clutch, and has a shaft end which points away from the balancing head and which includes a face pointing away from the balancing head substantially in the axial direction of the shaft. The shaft end has a weakening in the material in a subsection between the face and the balancing head in order for the shaft end to plastically deform radially outward in relation to the longitudinal axis of the shaft when a compressive force is applied to the balancing head in the axial direction. This especially allows the face of the shaft end to about a part of the friction clutch once the shaft has been introduced into a receiving opening in the friction clutch, and makes it possible to apply a compressive force to the balancing head in the direction of insertion, said compressive force being so great that the shaft end is plastically deformed in a particularly easy manner in the region of the weakening in the material such that a secure form-fitting connection is established, thereby preventing the balancing element from coming loose again even when the assembly space is tight and keeping the risk of the friction clutch becoming unbalanced low during the entire service life of the friction clutch.

A half-shaft assembly includes a first constant velocity (CV) joint, a second CV joint and an axial movement joint connected between the first CV joint and the second CV joint. The axial movement joint includes a first shaft coupled to the first CV joint and a second shaft coupled to the second CV joint, wherein mechanical input received on the first shaft is communicated to the second shaft, and wherein the second shaft slides axially within the first shaft. The axial movement joint further includes an axial boot cover coupled on a first end to the first shaft and on a second end to the second shaft that accommodates axial movement of the first shaft relative to the second shaft. The first constant velocity (CV) joint is coupled to provide torsional input received at an input to the first shaft, the first CV joint having a first CV boot cover. The second CV joint coupled to provide torsional output received from the second shaft to an output, the second CV joint having a second CV boot cover.

A half-shaft assembly includes a first constant velocity (CV) joint, a second CV joint and an axial movement joint connected between the first CV joint and the second CV joint. The axial movement joint includes a first shaft coupled to the first CV joint and a second shaft coupled to the second CV joint, wherein mechanical input received on the first shaft is communicated to the second shaft, and wherein the second shaft slides axially within the first shaft. The axial movement joint further includes an axial boot cover coupled on a first end to the first shaft and on a second end to the second shaft that accommodates axial movement of the first shaft relative to the second shaft.

A speed change device that includes a first clutch that has a first piston, a first engagement oil chamber, and a first centrifugal hydraulic pressure cancellation chamber configured to cancel a centrifugal hydraulic pressure generated in the first engagement oil chamber; a second clutch that has a second piston, a second engagement oil chamber, and a second centrifugal hydraulic pressure cancellation chamber configured to cancel a centrifugal hydraulic pressure generated in the second engagement oil chamber and that is disposed around the first clutch; and a drum member that defines the first engagement oil chamber together with the first piston and that defines the second engagement oil chamber together with the second piston.