A New Generation of Powershift Transmissions for Machines in the Construction Industry 810515
Modern construction machinery requires high quality and high reliability transmissions. There is demand for extended life time and low noise level at full power shifts in all speeds and at reversing in 1st and 2nd speed.
Economy - maintaining a wide range of application - will be a determining factor.
A transmission design has been chosen which offers 3-, 4-, and 6-speed versions with alternate ratios. Only few parts are to be exchanged.
One of the features is the cost-minimizing one-piece housing with spindles.
The control system has to guarantee the transmission of the power by the clutch packages and has to provide soft shift in all speeds.
The praxis shows that today 70% of the control systems are electro-hydraulically operated. A safety coding ensures best operating comfort and highest safety. Remote control, semi-automatic control and twin control stands can easily be realized. Features like start-up lock, reversing lock, pressure cut-off or converter lock-up are quite common.
Hydrodynamic torque converters are a standard element in transmissions for construction machinery. Torque multiplication and automatic adaptation to working conditions provide for easy machine operation also in rough terrain. Naturally, the torque converters equalize forced oscillations and protect for overload. The drive train efficiency can be increased by additional installation of stator freewheel and brake freewheel.
In certain applications the torque converter may be replaced by pressure-oil lubricated and cooled multi-disc clutches. Wet clutch resp. modulating clutch.
Another important element incorporated in the drive line is the wearfree, hydraulically operated retarder with its low idling loss.
The new transmission range offers up to three P.T.O. drives. Each permits full engine power take-off. One P.T.O. optional converter or reversing transmission connected.
Due to an extensive transmission component program, the various drive train requirements for construction machinery can be met.
The application of this transmission range also includes crawler tractors, loaders, highspeed dumpers, or RT cranes.