Zf Friedrichshafen Ag

Zahnradfabrik Friedrichshafen, Ag.

Erwin Baur

Herbert Simon

Franz Muller

Helmut Konrad

Jurgen Pohlenz

Hubert Lehle

Hubert Sailer

Walter Fischer

Jürgen Pohlenz

Christian Herrmann

Tobias Kreß

Franz M&uuml;ller

Frank Hirschmann

A transmission device with secondarily coupled power splitting, having hydrostatic and mechanical branches which can be summed by a summing gear system provided in the area of a central transmission shaft. At least two transmission ratio ranges, in the forward and reverse driving directions, can be obtained such that within the transmission ratio ranges the transmission ratio can, in each case, be varied continuously by a hydrostatic variator in the area of the hydrostatic branch. On the transmission input side, the central transmission shaft can directly couple a drive engine and functionally connect to both an auxiliary drive output shaft and a hydrostatic shaft of the variator, in the form of countershafts, and also to hydraulic pumps in the area of the transmission input. In the area of the transmission output, the central transmission shaft is coupled to a further hydrostatic shaft in the form of a countershaft.

Transmission device with secondarily coupled power split

Multi-disk clutch connected downstream of a power split transmission consisting of a double clutch whose individual clutches rotate in opposite directions, the rotational-speed dependent axial forces being compensated on the shift piston, and has a valve which releases or blocks the flow of coolant to the disks and a return spring with an increasing spring characteristic line for calibrating the clutch.

Multi-disk clutch in a power split transmission

The invention relates to a continuously variable transmission with two driving modes designed as split power transmission comprising a power branch in the form of a variator with a continuously adjustable rotational speed and a mechanical power branch. The mechanical power branch and the variator are coupled in the first driving mode with a compound gear. The mechanical power branch is opened in the second driving mode and the total power is directly transmitted by the variator. Both driving modes can be switched by clutches K,and K,and can be optionally connected to the transmission input shaft (,) by means of a clutch Kv for forward drive and via a clutch Kr for reverse drive. The clutches Kv and Kr are designed as a twin clutch which acts as a start clutch and as a reverse unit.

Continuously variable transmission

Gear change box with multiple steps

In a mechanism for driving motor vehicles having a synchromesh gearbox with a friction clutch for each of two power branches with at least four power shiftable speeds and consecutive speeds are alternatively present on each one of the two power branches. Each friction clutch is a wet disc clutch with its inner discs having continuous radial grooves for a cooling oil flow supplied from a bore in a shaft. A switch piston shuts off the flow of cooling oil when the friction clutch is disengaged or almost completely disengaged. A prestressed cup spring in a compensating cylinder serves as a strong return spring thereby accelerating disengagement or delaying engagement of the friction clutch. Corrugated spring rings, axially situated between the inner discs and radially within the outer discs, serve as additional return springs. The wet clutch operates as a dry clutch and only has a low torque when it is disengaged. A large flow of cooling oil flows to the friction clutch and cools it as it engages and when it is engaged. The wet friction clutch replaces a conventional dry friction clutch, especially when starting up the motor vehicle.

Vehicle driving mechanism having a synchromesh gearbox with an

Growing community of inventors

Oberteuringen, Germany

Erwin Baur