WORM GEAR ANALYSIS IN TERMS OF NUMERICAL MODELLING

A worm gear mechanism, widely used in numerous mechanical applications, is the essential component in energy ef­ficiency considerations. Compared to traditional gearboxes, worm gear is characterized by lower value of efficiency, provided by the manufacturers as 70-90%. However, the efficiency level can differ depending on the specific conditions of operation such as output torque, input rotational velocity, ambient temperature and type of lubrication. In order to analyse and simulate the worm gear mechanism in mechanical systems, it is essential to establish the actual efficiency value for specific conditions. The following article contains the description of efficiency test performed for the worm gear as a part of tram pantograph system studied in frame of ESTOMAD project. The aim of the experiment was to deter­mine the actual efficiency value of the transmission tested. The worm gear has been tested in an open loop configuration, therefore the efficiency has been determined basing on input and output torque and rotational velocity measurements. The tests have been performed for various output torques and input velocities to obtain view on losses in worm gear under different operational conditions, paying special attention to the velocity that drives the pantograph mechanism. The efficiency changes with the output torque variation, while the impact of rotational velocity level on the mentioned value is minimal. The results of measurements are used in modelling phase of worm gear component in 1D simulation environment, particularly creating new model and its correlation and validation.