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Design and Fabrication of Progressive Gearbox Report Download

ABSTRACT

This project mainly deals about design and fabrication of self progressing gear box. A gear box is an assembly of gears which is used for controlling the speed and has many applications widely, even in automobiles gear box is implemented and various improvements are done day by day. One of the improvements done in gear box is auto changing. In our project a prototype of this gearbox for auto changing for gears is done with the help of a governor mechanism. The assembly consists of a set of gears connected to the motor through the governor. The governor is attached to the driver shaft. At initial position there will be no engagement of gears for power transmission. When the speed begins to increase in the driver shaft due to presence of the governor the initial height reduces and the shaft moves and engages with the first gear and power is transmitted to the driven shaft. As the speed further increase in speed will cause the second gear to engage. And vice versa when the speed reduces and the driver shaft will return to the initial position with the help of the spring. The design procedures, drawings for the above mentioned project is given below.

INTRODUCTION

A progressive gearbox is a gearbox which changes the gear according to speed variation. This movement for the gears based on speed is done with the help of governor. Its main function is to shift the gears in forward as speed increases and vice versa when the speed decreases. The governor plays vital role in changing of gears. By using a prime mover (Motor) and governor mechanism the forward and reverse motion of driving shaft is achieved.

WORKING PRINCIPLE

The working of this gearbox is same as ordinary gearbox except for the gear shifting automatically as the speed increases. As initial in rest position no gears will be engaged and hence no power transmission for the driving to the driven wheel is obtained.
Then when the driving shaft begins to rotate due to the centrifugal force the governor begins to expand. Since the governor is attached to the driving shaft the sliding shaft also slides towards the governor.
As the driving shaft attains a particular speed the first set of gears will begin to engage and power is transmitted to the driven shaft.
Even further improvement in speed ill cause the 2nd set of gears to engage. Then as the speed reduces due to the spring force the sliding shaft will move away from the governor. And it finally disengages from all gears and comes to neutral position.