Modular Design of Hydromechanical Transmissions for Mobile Working Machines

Abstract

This paper demonstrates an optimisation-based method of designing modular gearboxes scal- able for a range of applications. The design is adapted to the typical operating behaviours of the reference vehicles and considers the manufacturing costs of the gearboxes. Hydromech- anical continuously variable transmissions (CVTs) are today strong candidates to replace drive line transmissions based on fuel-thirsty torque converters in many mobile working ma- chines. The advantages include a wide range of torque/speed ratios, high energy efficiency throughout the speed range and decoupling of engine speed and vehicle speed. Advanced multiple mode CVTs, however, are difficult to evaluate early in the product development pro- cess due to their complex architectures and the great variety of possible concepts. There is consequently an increased need for methods to design, compare and evaluate the transmis- sion concepts. To decrease the development and manufacturing costs, there is also a need for scalable transmission concepts that can be used in several applications of different classes. The results show the proficiency of the methodology compared to a manual design process and