Zf Friedrichshafen Ag

Markus Maurer

Ruben Cueppers

Dominik Steinhauser

Torsten Buechner

Max Trautwein

Andreas Schmidt

Martina Jehle

Christian Villing

Tobias Brand

A method for operating a vehicle drive train () comprising a prime mover (), transmission (), and comprising a driven end () may include limiting, during a demand for engaging a form-locking shift element (A, F) of the transmission () when a rotational speed of the driven end () is close to zero, a rate of change of a transmission input torque present at the form-locking shift element (A, F) to a value. Below the value, forces present at the form-locking shift element (A, F) during an engagement process are less than a load limit. Above the value, irreversible damage to the form-locking shift element (A, F) occurs.

Method and control apparatus for operating a vehicle drive train

A method for operating an automatic transmission includes determining at least one of an elapsed time from adjusting a first one of at least one positive-locking shift element towards a closed configuration or a differential speed rotation of the first one of the at least one positive-locking shift element and shifting the automatic transmission to a substitute gear if the elapsed time from adjusting the first one of the at least one positive-locking shift element towards the closed configuration reaches or exceeds a time limit and/or the differential speed rotation of the first one of the at least one positive-locking shift element reaches or exceeds a rotational speed limit. A related transmission control device for an automatic transmission is also provided.

Method and control device for operating an automatic transmission

A method for operating an automatic transmission is provided. The method includes initiating a synchronization of a positive shifting element of the automatic transmission. The method also includes closing a first non-positive shifting element of the automatic transmission and positioning a second non-positive shifting element of the automatic transmission at an engaged configuration of the second non-positive shifting element during the synchronization of the first positive shifting element in order to synchronize the first positive shifting element.

Method for operating an automatic transmission

A method is provided for executing a gearshift in an automatic transmission with several shifting elements. Upon the execution of the gearshift, a first frictional-locking shifting element is opened and a second positive-locking shifting element is closed. If, upon the execution of the gearshift, an input torque of the automatic transmission is less than a threshold value, after at least partially opening the frictional-locking shifting element and after releasing the positive-locking shifting element, there is a monitoring of whether the positive-locking shifting element is transferred into its end position. If it is then determined that the positive-locking shifting element is not in its end position, a torque transferred by the partially open frictional-locking shifting element initially increases. If, despite the increase in torque transferred by the frictional-locking shifting element, the positive-locking shifting element is not in its end position, the operating pressure of the positive-locking shifting element is then increased.

Method for executing a gearshift in an automatic transmission

A method for operating an automatic transmission is provided. The method includes synchronizing a positive shifting element of the automatic transmission, braking the automatic transmission with a first non-positive shifting element of the automatic transmission, establishing a position of the positive shifting element, and increasing a pressure of fluid supplied to a second non-positive shifting element of the automatic transmission if the position of the positive shifting element is an intermediate position.

A method of shifting at least one of a speed increasing stage (H) and/or a speed reductions stage (L) in a claw shifted transfer gear box (VG) in a drive train of a vehicle having a drive engine and a load shiftable shift transmission (SG). The transfer gearbox (VG) is shifted into the neutral position (N) and, after the synchronization, is shifted into the speed increasing stage (H) or the speed reductions stage (L). During synchronization, the shift transmission (SG) is decelerated or accelerated, by activating at least an additional shift element, so that the output rotational speed (n_SG) of the shift transmission (SG) is matched to the output rotational speed (n_VG) of the transfer gearbox (VG), multiplied by the target gear ratio in the transfer gear box (VG).

Method for engaging at least one speed-increasing or speed reduction stage in a transfer box

A transmission comprising a transmission () and a reduction stage. Sun of set (P) is connected to the input (), which can be releasably connected, via clutch (A), to shaft () connected to sun of set (P) and sun of set (P), and, via clutch (B), is connectable to shaft () connected to carrier of set (P) and ring of set (P). Shaft () is coupled to housing (G) via brake (F). Carrier of set (P) is connected to shaft () connected with ring of set (P) and is couplable, via brake (E), to housing (G). Ring of set (P) is connected to shaft () which is couplable, via brake (D), to housing (G). Output () is connected to carrier of set (P). Carrier of set (P) is connected to output (), ring of set (P) is couplable, via brake (H), to housing (G), and sun of set (P) is connected to the shaft ().

Multistage transmission

A transmission having basic and reversing transmissions. The basic transmission has planetary gearsets, shafts and shift elements. A sun of gearset (P) couples the drive shaft, which can couple shaft () and the suns of gearsets (P, P), and shaft () and the carrier and ring of gearsets (P, P) respectively. Carrier of gearset (P) couples shaft (), which couples the ring of gearset (P). The ring of gearset (P) couples shaft (). Shafts () can couple the housing. The output shaft couples the carrier of gearset (P). The reversing transmission has a minus planetary gearset with a sun which couples and is driven by the basic transmission output, and a carrier that can couple the housing via a locking element, and a ring that couples the reversing transmission output which can couple, via another locking element, the basic transmission output.

A multistage transmission in planetary design is proposed, comprising a basic transmission () and a group transmission () downstream of the basic transmission (), wherein the basic transmission () comprises three planetary gear set (P, P, P), at least six rotatable shafts () and at least five shift elements (A, B, D, E, F), the selected engagement of which results in different transmission ratios between the input drive and the output drive, wherein the group transmission () has a minus planetary gear set (P), the sun gear of which is connected to the output shaft () of the basic transmission (), the ring gear of which can be coupled to the housing (G) via a first shift element (K), and the carrier of which is connected to the output shaft () of the multistage transmission, which can be releasably connected to the ring gear via a second shift element (K), and wherein the basic transmission () and the group transmission () are disposed in a common housing (G).

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Lindau, Germany

Markus Maurer