Disclosed and claimed is a double-acting cylinder comprising a cylinder housing, a first floating piston, a second floating piston and a central piston which is movable to three stationary positions along an actuation direction of the cylinder. A movement of the floating pistons in the cylinder bore is delimited by end stop arrangements. A movement of the central piston in the cylinder bore is delimited by the first and the second floating piston. Each floating piston comprises a first section and a second section. A circumferential length of the floating pistons is greater in the first section than in the second section. In the first sections a first seal is arranged for a sealing engagement with an inner wall of the cylinder bore. In the second sections a second seal is arranged for a sealing engagement with the inner wall of the cylinder bore or an inner wall of the central piston.

A modular shifting system is provided. The modular shifting system comprises a transmission including an input shaft and an output shaft, a transmission housing, gear trains accommodated in the transmission housing and constituting at least two shiftable gear ratios for establishing a transmission ratio between the output shaft and the input shaft, and a shift device for shifting between the at least two gear ratios. The shift device is detachably attached to the transmission housing. The shift device is one of an electrically actuated shift device and a pneumatically actuated shift device. The modular shifting system is configured such that the electrically actuated shift device is interchangeable with the pneumatically actuated shift device and vice versa.

A hybrid drive device for a motor vehicle includes an internal combustion engine, an electric machine, and two planetary gear trains which are shiftable into different gear stages by shifting elements and which are connectable via input elements and output elements with a driven input shaft and an output shaft and have shiftable transmission elements that can be coupled or braked. The internal combustion engine is in driving relation to a first input shaft and the electric machine is in driving relation to a second coaxial input shaft. The two planetary gear trains are coupled to each other such that, when the shifting elements are activated, shifting of four forward gears can be implemented via the internal combustion engine and shifting of three forward gears or reverse gears can be implemented via the electric machine.