ZF Sachs AG Ernst-Sachs-Straße 62 97424 Schweinfurt Germany phone: +49 9721 98-0 fax: +49 9721 98-2290 www.zf.com
Torque Converters
For Construction Machinery
Driveline and Chassis Technology
© ZF Sachs AG-Construction Machinery-Torque Converter-04/2010
and Lift Trucks
More Comfort and Less Fuel Consumption – Torque Converters by ZF Sachs
Torque for Every Construction Machinery Application With a hydrodynamic diameter of 280 up to 400 millimeters, torque converters by ZF Sachs can easily be used for engine torques up to 2,700 Nm. Thus, not only the entire torque converter range of construction machinery is covered, but also all individual requirements of manufacturers and operators can be fulfilled. The individual
What applies to commercial vehicles in general is also true for construction machinery in particular: Requirements for vehicles are on the rise. On the one hand, construction machines are supposed to be versatile, economically viable, and reliable, while on the other hand of course they should also be saving fuel. With its highly efficient and individually adaptable torque converters, ZF Sachs AG is masterfully bridging these two sets of requirements for its area of expertise. With millimeter-precise accuracy for maneuvering, swift loading and unloading, a high and even level of power transfer, quick and smooth shift processes – construction machinery has to be highly versatile and reliable. And all of this more so than ever! In order for lift trucks, telescopic handlers, backhoe loaders, wheel loaders and dump trucks to successfully complete the tasks assigned by their owners or drivers, all components of the driveline have to be optimally harmonized with one another. Today, no one can conceive of working without the valuable assistance of vehicles equipped with hydrodynamic torque converters. ZF Sachs offers a broad spectrum of torque converters here in different model versions. Due to its ongoing development work, ZF Sachs is able to provide production-ready solutions today that already meet the requirements of the future.
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matching of performance and model type to the respective application makes torque converters from ZF Sachs extraordinarily effective.
Application
Torque Converter
Backhoe Loader/ Lift Truck Telescopic Handler
W280
W300
W280
W300
Dump
Wheel Loader
W300
W340
Truck
W400
W400
Free-wheel Unit
Torsional Damper
Lock-up Clutch LUC
Standard
Optional
Future Trend
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Torque Converters for Every Torque Range
Torque for every construction machinery application
The task:
The technology:
Hydrodynamic torque converters are used
Torque converters from ZF Sachs are known for their robust design.
in construction machinery with automatic
Thanks to individual adaptation of engine and converter
transmissions. The engine torque is
characteristics, they are optimally designed for any given application
passed to the transmission via the torque
with respect to both function and service life. After the drive-off
converter using oil as a transfer medium.
process, the optional lock-up clutch enables torque flow to be
A high and even level of power transfer as
transferred directly and thus with no loss of power between the
well as quick and smooth shift processes
engine and the transmission. This contributes substantially
are a must. Because hydrodynamic
lowering fuel consumption levels and enhancing cost-effectiveness
power transfer is fuel-intensive, lock-up
for construction machinery. ZF Sachs torque converters are
clutch ensures direct torque flow between
featuring new free-wheel designs to cope with the highly dynamic
engine and transmission after the drive-off
gear-shifting processes which occur in transmissions these days. The
process. To protect the transmission,
vibrational problems that arise in the driveline when engines are
torsional vibrations have to be “filtered
optimized for fuel consumption and emissions are being addressed
out”.
by integrating torsional dampers into the torque converter.
Engine torque [Nm]
3,000
The required converter size depends on the engine torque to be transmitted.
2,500 2,000 1,500 1,000 500 0
W280
W300
W340
W400
Converter size Ø [mm]
Design of W340 LUC/TD for wheel loaders
Engine connection
Impeller Lock-up clutch with torsional damper Turbine
Stator
Free-wheel Oil pump drive
Power take-off
W300 LUC/TD 4
W400 LUC 5
Details of Lock-up Clutch Systems
Comparison of vibrational decoupling for converters with and without torsional damper (TD) Angular acceleration [1/s²]
Benefits ■■ Longer service life thanks to protection of driveline components ■■ Reduced fuel consumption because required rpm levels can be lowered ■■ Reduced noise emission
Converter with lock-up clutch with 1 friction facing in dual-line system Lock-up clutch disengaged
Lock-up clutch engaged Torque converters with lock-up clutch using a dual-line principle are used primarily in backhoe loaders and telescopic handlers. The lock-up clutch can transmit up to 500 Nm of torque.
Operational range Converter without TD Converter with TD 500
1,000
1,500
2,000
2,500 Speed [rpm]
Oil flow
Torque flow
Torque converter efficiency Like every other hydraulic machine, torque converters do not work without losses. The efficiency of a torque converter in hydrodynamic mode is about 90 %. A torque converter lock-up clutch enables torque flow to be transferred directly between engine and transmission. As soon as the lock-up clutch is engaged the efficiency of the torque converter is approximately 100 %.
5 approx. 100 %
Gear
4
3
Converter with lock-up clutch with 1 friction facing in open three-line system
Lock-up clutch disengaged
Lock-up clutch engaged Torque converters with lock-up clutch using an open three-line principle are also used primarily in backhoe loaders and telescopic handlers. The threeline system and the enhanced heat transfer mean that the lock-up clutch can be engaged earlier. This optimizes fuel consumption all the more.
2 approx. 100 % 1
max. 90 %
max. 90 % Without lock-up clutch
Lock-up clutch engaged in fourth gear Lock-up clutch disengaged
max. 90 % Lock-up clutch engaged as of second gear
Oil flow
Lock-up clutch engaged
Converter with lock-up clutch with 4 friction facing in closed three-line system
Reduced fuel consumption with lock-up clutch
Fuel consumption
+
0
6
refuel
refuel
Torque flow
without lock-up clutch Fuel savings of up to 15 % with lock-up clutch
Fuel consumption can be lowered by up to 15 %, depending on the load cycle and service conditions, as well as the gear in which lock-up clutch is engaged.
Lock-up clutch disengaged
Torque converters with lock-up clutch using a closed three-line principle are used primarily in dump trucks and wheel loaders. In addition to the advantages of the open three-line system, here there is a longer service life. This is because the lock-up clutch’s shift function can be better modulated thanks to the closed control line.
with lock-up clutch
Driving time/distance
Lock-up clutch engaged
Oil flow
Torque flow
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