Properties and sizing methods of 2-motor transmissions

Authors

  • Roberto Paoluzzi C.N.R.-IMAMOTER Institute for Agricultural and Earthmoving Machines, National Research Council of Italy, Ferrara, Italy http://orcid.org/0000-0001-5857-5972
  • Luca G. Zarotti C.N.R.-IMAMOTER Institute for Agricultural and Earthmoving Machines, National Research Council of Italy, Ferrara, Italy

DOI:

https://doi.org/10.1080/14399776.2016.1234873

Keywords:

Fluid power, transmissions, off-road machines, volumetric machines

Abstract

The hydrostatic transmissions are often used to operate the drive train of off-road machines (wheeled or tracked) due to their advantages, e.g. compact size, little inertia, wide speed range, dynamic braking. Since the typical transmission with one pump and one motor (named Type A for convenience) features a rather limited application range – i.e. compatibility of specifications in terms of engine power, maximum traction and top speed – the paper reviews three improvementes to expand it without introducing too much complexity: the addition of a gearbox in series (Type B), and two alternative schemes with two motors: fixed and variable (Type C), or both variable (Type D). The constraints on size, setting and speed of the main hydraulic units dictated by each of the configurations are disclosed and their consistent design rules are discussed in detail on the basis of discrete series of heavy duty pumps and motors taken from the technical literature. To highlight the realistic implementation of the transmissions with two motors, the conventional traction vs. speed curves of three Type C and D transmissions are compared by interpolating 2-D and 3-D efficiency tables.

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Author Biographies

Roberto Paoluzzi, C.N.R.-IMAMOTER Institute for Agricultural and Earthmoving Machines, National Research Council of Italy, Ferrara, Italy

Roberto Paoluzzi, born in Ferrara in 1961, received the degree in Nuclear Engineering from the University of Bologna in 1986. Since 1988 he joined the Institute for Agricultural and Earthmoving Machines of the National Research Council of Italy (CNR). From 2009 until his sudden death on September 13th 2016, he was the director of the same Institute from 2002 to 2009. Main interests in the field of fluid power transmission, computational fluid dynamics and functional analysis of the safety of machinery. He is the author or co-author of over 200 scientific

Luca G. Zarotti, C.N.R.-IMAMOTER Institute for Agricultural and Earthmoving Machines, National Research Council of Italy, Ferrara, Italy

Luca G. Zarotti, born on November 20th 1945 in Parma, he received the Degree in Aeronautical Engineering at the Polytechnic Institute of Torino (1970). In 1971, he joined the Institute for Agricultural and Earthmoving Machines of the National Research Council of Italy (CNR), where he is still working. He was the director of the same Institute from 2002 to 2009. He had in charge the fluid power course at the Polytechnic Institute of Torino (from 1979 to 1982) and the University of Modena & Reggio E. (from 1996 to 1999), and the University of Ferrara (from 2002 to 2012). His research interests cover various aspects of hydrostatic locomotion, displacement control of pumps and motors, load sensing and flow sharing systems for mobile applications. Besides a number of papers and articles, he is the author of Monographs on fluid power fluids (2006), Fluid power circuits (2006 and 2010) and Hydrostatic transmissions (2010). Retired at the end of 2012, he still works on fluid power projects with the Institute as an associate researcher.

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Published

2017-03-01

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