ZF cPower – Hydrostatic-Mechanical Powersplit Transmission for Construction and Forest Machinery

• Main Authors: Legner, Jürgen, Rebholz, Wolfgang, Morrison, Robert
• Other Authors: Dresdner Verein zur Förderung der Fluidtechnik e. V. ,
• Format: Others
• Language: English
• Published: Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden 2016
• Subjects: ddc:620; rvk:ZQ 5460
• Online Access: http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200376; http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200376; http://www.qucosa.de/fileadmin/data/qucosa/documents/20037/8-1_PDF_A_ZF%20cPower%20-%20hydrostatic-mechanical%20powersplit%20Transmission.pdf

Until recently, hydrostatic-mechanical power split CVT drivelines have not found a place in construction machinery. The majority of these vehicles still use hydrodynamic powershift transmissions, full-hydrostatic transmissions or mechanical direct-shift transmissions. Hydrostatic drive lines are widely used in construction machinery possessing lower engine power. The upper power range is dominated by hydrodynamic powershift transmissions. Decisions made by vehicle manufacturers about which driveline technology to be used, have been based mainly on reliability, durability, and cost. Fuel economy has also been a growing trend over the past years; however the additional cost of higher technologies must be compensated by the savings in fuel cost over a time period of 2-3 years. The transmission’s efficiency highly contributes to the vehicle’s fuel consumption. ZF has thoroughly studied the possible concepts of hydrostatic-mechanical power split transmissions. The most important requirements of reliability, durability and efficiency were taken into consideration during the concept study. An examination the most typical working cycles showed that a construction machinery transmission needs to be fully power split in all ranges and obtain equal performance in both driving directions. It was also observed that up to 60% of productive time for construction and forestry equipment was spent at a speed below 12 km/h. For this speed range, achieving the highest possible efficiency is vital. The result of this research is the ZF cPower, which is an output-coupled, fully power split transmission.