The paper will describe the enhancements in the overall efficiency of a construction machine that can be obtained by using a dual displacement crankshaft design radial piston hydraulic motor capable of running at very high speeds. Different products have been examined in order to cover a wide range of applications and working conditions. Most of the results are the outcome of significant application studies, which led to the development of prototypes. The common essential feature of all the prototypes was a dual displacement system applied to a crankshaft design radial piston hydraulic motor suitable for very high speeds. Some of the prototypes are currently used by major world-wide construction industries. A typical system to be developed was a dual speed hydraulic transmission. Most of the construction machines in fact, are being designed for having two operational modes: the slow mode, when the machine is under heavy loads and moves with a relatively low speed, and the fast mode, when the machine is virtually unloaded and moves faster on the work ground. The variation of the motor displacement is obtained by a variation of the eccentricity of the crank of the shaft. Hence, the motor can shift in a continuous manner from the maximum to the minimum displacement, with a smooth variation in terms of torque and speed. The wide operational range coupled with very high efficiency both in minimum and in maximum displacement, allows the hydraulic system to adjust the engine working conditions in a smaller range closer to that of the maximum efficiency. The major consequences being less exhaust emissions, less thermal losses, longer machine life, without forgoing the performances of the equipment, rather improving them. The objectives of the analysis were to capture the essential benefits of the application of these hydraulic components referring in particular to the overall efficiency in order to determine the enhancements with respect to the traditional hydraulic motors. The ultimate aim was to identify candidates for optimal application in terms of performance and design. The results obtained show that with the use of such a component, thanks to its high starting torque, even in minimum displacement, and its very high maximum speed, the system gains elasticity, performance and overall efficiency.


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    Title :

    Latest development of crankshaft design radial piston hydraulic motors: High torque highspeed variable displacement motors for hydrostatic transmissions


    Contributors:


    Publication date :

    2007


    Size :

    12 Seiten, 10 Bilder, 3 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English





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