Zf Friedrichshafen Ag

Markus Renninger

Johannes Kaltenbach

Michael Wechs

Thomas Rosemeier

Ralf Dreibholz

Juergen Wafzig

Rudolf Kauffeldt

Jürgen Wafzig

Christian Michel

A countershaft-type dual clutch transmission for a vehicle has two clutches having input sides connected to a driveshaft (AN) and output sides connected respectively to one of two transmission input shafts arranged coaxial to a mainshaft axis. A sub-transmission is associated in each instance with the transmission input shafts, at least two countershafts, a plurality of gear planes to which are assigned gear ratio steps, and at least one output shaft which can be connected to the sub-transmissions via an output gear plane. Only six gear planes with at least nine assigned gear ratio steps can be realized via only four double shift elements and at least one single shift element. Each countershaft can be coupled with four gear ratio steps via double shift elements, and one of the transmission input shafts can be coupled with a gear ratio step via a single shift element.

Dual-clutch transmission

A dual clutch transmission designed as a reduction gearing which has concentric central and hollow transmission shafts, exactly one layshaft, and two power shift elements. A hollow shaft is provided coaxially on the layshaft, which can be rotatably fixed to the layshaft, via one shift device, and to which at least two gears of the gear stages are rotatably fixed. A further hollow shaft is provided coaxially on either the central or the hollow transmission shaft, which can be connected, via one of the shift devices, with the central or the hollow transmission shaft and to which at least two further gears of the gear stages are rotatably fixed. At least three transmission ratios are obtainable as a result of engaging the shift element into the power flow in three of the gear stages, by which one transmission ratio results from engaging only one shift element into the power flow.

Dual clutch transmission designed as reduction gearing

A double clutch transmission of countershaft design having a central shaft and a concentric hollow transmission shaft, one countershaft, and two power-shift elements. Two hollow shafts are disposed on the countershaft coaxially to the countershaft, each of which can be fixed, via one shift device, to the countershaft, and to which at least two gearwheels are fixed. A further hollow shaft is coaxially provided on either the central or hollow transmission shafts and can be connected, via a shift device, to the central or hollow transmission shaft, and to which at least two further gearwheels of the gear stages are fixed. At least three transmission ratios are possible by engaging three of the gear stages on the shift-element side into the power flow, thereby enabling one transmission ratio to be at least partially implemented by a respective sole engagement on the shift-element side into the power flow.

Double clutch transmission having a layshaft design

A self-pumping suspension strut with internal level regulation, for example for motor vehicles having a fluid-filled working cylinder pressurized with the pressure of the fluid acting as a spring. A hollow piston rod is guided, in a sealed manner, within the working space, into which projects a pump piston attached to the working cylinder. During relative movements between the working cylinder and the piston rod, fluid is delivered from the working space into a pressure chamber in which a pressure is higher than the pressure of the working space. Flow connections between the pressure chamber and the working space selective set a specifiable dynamic level, determined by the extension length of the piston rod, such that the piston rod can be rotated, by a rotating device, for selective cooperation of the axially and the circumferentially spaced flow connections to control flow.

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Oerlenbach, Germany

Markus Renninger