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Design of Agricultural Tractor Transmission Elements

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Design of Agricultural Tractor Transmission Elements. ASAE Distinguished Lecture No. 4, pp. 1-32. Winter Meeting of the American Society of Agricultural Engineers, 18 December 1978, Chicago, Illinois  903C0578.(doi:)
Authors:   E. Paul Browning
Keywords:   Engine Input, Transmission Output, PTO Output, Operator Input, Computer Calculations, Clutch Design, Transmission Shafting, Gear Design, Bearings, Bearing Types, Bearing Life, Bearing Design, Synchronizers, Ratio Calculations, Torque, Power and Efficiency, Planetary Assembly, Infinitely Variable Transmission Elements, Conventional Hydrodynamic (Torque Converter), Hydrostatic Infinitely Variable Transmissions, Conventional Mechanical, Hydrostatic Power-Splitting (Hydromechanical Transmissions), Three Shaft System-Input Coupled, Three Shaft System-Output Coupled, Four Shaft System, Internal-External Rotor Pump, Lubrication, Power-Splitting Mechanical Transmissions, Hydraulic Pumps for Transmissions, Spur Gear Pump, Internal-External Gear Pump, Hydraulic Control Valves, Check Valves, Relief Valves, Pressure Regulating Valves, Directional Valves, Servo Valves (Pilot Valves), Pressure Modulation Valves, Valve Stability, Valve Leakage, Design Trends for the Future

Designing effectively entails disciplined methodology in the treatment and analysis of information. Being knowledgeable and inquisitive of product background and requirements and applying sound design techniques till help assure success in the design of transmission elements.

The text to follow is intended to supplement the machine design background of the reader with the hope that he will benefit from the references given and further his interest in deeper exploration of agricultural transmission design parameters. Texts such as Heldt(1)*, Barger(2), and Looman(3), and others will be useful in the establishing design details.

The scope of this paper covers the design of the components or elements that collectively constitute the working parts of a transmission. The selection of the proper transmission for a given application is a subject in itself and will have only brief comment. Customer and manufacturing requirements are involved.

Basic transmission function can be depicted in a flow diagram as shown in Fig. 1. Speed ratio is selected by the operator through manipulation of gear shift and clutch controls. The operator's satisfaction with the transmission function depends on design and execution detail.

A design criteria satisfying requirements established through evaluation, test, and simulation techniques has greater chances for success than one of unique design concept created prior to the establishment of objectives or design specification. Or in other words, transmission functional and operational characteristics needed to enhance in-field and transport vehicle performance should be identified early in a transmission engineering program with several of the more important considerations being:

Engine Input

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