HYDROSTATIC TRANSMISSION AS AN ALTERNATIVE TO CONVENTIONAL GEARBOX

Sumair Sunny, Sunny Pawar, Siddhesh Ozarkar, Sandeepan Biswas

Abstract: This project involves the replacement of a conventional gearbox transmission system by a Hydrostatic Transmission (HST) system. The applications being considered are those of typical off-road vehicles such as forestry, construction site or mining & quarry vehicles. In these applications speed is of less importance as compared to torque and load carrying capacity. To create a small scale simulation of the performance comparison between the two transmission systems, we are selecting a buggy as our test vehicle. The same engine (Briggs & Stratton Model 20, 10H.P.), as well as wheel base and wheel track being used for both simulations. Geometrically, both vehicles will remain exactly the same and under running conditions the weight required to be hauled is being considered as 350 kg. The only variation will be in the mountings of the two different transmission systems. The above criteria enables a fair simulation as well as comparison of the two transmission systems. The vehicle will be single seated with a curb weight of around 260 kg. The governor setting of the engine will remain unchanged for both simulations. 25” kings tire will be used with the tread pattern being KT168. The gearbox being considered is a ‘Mahindra Alpha Champion’ 4 speed gearbox. The purpose of choosing this as the transmission of our baseline vehicle is that it can operate its four gears in reverse as well. This is important as a HST system shows symmetrically opposite characteristics for both forward and reverse, hence making it a fair comparison. The hydrostatics pump and motor will be selected from Eaton product catalogues as this project has been offered to us, and is being guided by Eaton. The performance analysis is done on basis of Velocity, Acceleration and Grade-ability. The aim is to design a HST circuit which can closely match up to the performance offered by a gearbox transmission so as to verify whether a HST system can be a suitable replacement to a gearbox transmission for the above mentioned applications. This project involves valid database, data flow, algorithm and out reports. The actual fabrication would be too expensive and hence unfeasible. All self-designed parts will undergo Finite Element Analysis (FEA) using Altair Hypermesh. This will validate the design calculations. All the calculations have been done using Microsoft Excel and the final simulation has been done on MATLAB SIMULINK. All the modelling has been done using SolidWorks.

Keywords: HST, gearbox, engine, pump, motor, alternative, SIMULINK, hydrostatic, hydraulic, differential, worm

DOI: https://doi.org/10.15623/ijret.2014.0305028