Design of Two Stage Gearbox for EV

The global shift toward electric mobility has intensified the demand for efficient and compact power transmission systems capable of bridging the speed gap between high speed electric motors and the low speed high torque requirements of drive wheels. This project presents the design, fabrication, and demonstration of a two stage spur gear reduction gearbox developed to illustrate and validate the fundamental principles of electric vehicle power transmission in a physically accessible and cost effective manner. The gearbox is constructed around three parallel shafts of 15 mm diameter, each supported by standard bearings mounted in laser cut steel side plates of 10 mm thickness, with the remaining faces of the housing enclosed by welded 5 mm steel panels to form a rigid and compact box type structure that eliminates the need for conventional casting or complex machining operations. The gear train is arranged across the three shafts to deliver two successive stages of spur gear speed reduction. The first stage consists of a 110 mm diameter driving gear on the input shaft meshing with a 44 mm diameter gear on the intermediate shaft. The second stage consists of a 60 mm diameter gear on the intermediate shaft meshing with a 40 mm diameter gear on the output shaft.