An enclosed system of assembled gears that transmits mechanical energy from a prime mover to an output device. A gearbox can also change the speed, direction, or torque of mechanical energy. A thrust bearing is a particular type of rotary bearing. Like other bearings they permit rotation between parts, but they are designed to support a high axial load while doingthis. Generally, they are composed of two washers (raceways) in which those for ball bearings may be grooved, and the rollingelements. Thrust bearings are designed to manage thrust (axial) loads and provide high-shock-load resistance in a variety of applications. After a product is designed, usually by an industrial designer or an engineer, moulds are made by a mould maker (or toolmaker) from metal, usually either steel or aluminium, and precision-machined to form the features of the desired part. Injection molding is widely used for manufacturing a variety of parts, from the smallest component to entire bodypanels of cars
The model of gear box of plastic injection moulding machine was analized. There are some problems occur in plastic injection moulding machine like , wearing of gears, failure of bearing, misalignment of shaft, lack of lubrication, etc. But the major problem occur from the above is failure of bearing. This problem is occur due to excessive axial thrustload.