GEAR AND ITS CLASSIFICATION - PART 2

GEARS WITH INTERSECTING SHAFTS

•    BEVEL GEARS

·  Straight bevel gears

·  Spiral bevel gears

This is second classification of gears where the axis of driven gear and driver gear are not parallel; rather they are intersecting in nature. When the axis of both driver and driven gears are at 90 degrees then such gears are named as bevel gears. The teeth have angular cuts on their surface. Apart from their advantage of transfer of power at right angle and high speed, it can take up large loads with precision, their disadvantage lies in complicated shape fabrication and manufacturing and sometimes improper meshing.

STRAIGHT  AND SPIRAL BEVEL GEARS

In various applications like differential of automobiles, conveyor system etc straight bevel gears are employed. These can provide velocity ratio in ( 1:1 ) or higher ratio.\

The spiral bevel gears are another classification of intersecting shaft gear where the contact area of tooth is more due to spiral shape of tooth. These can carry larger load not has lesser efficiency then straight bevel gears. Mostly these are used in automobiles for transmitting power.

HYPOID GEARS

Such gears can be placed between straight cut and worm gear. One hypoid shaped gear slides over another; as such slipping phenomenon is predominant. Lubrication is necessary in order to avoid frictional wear. These gears can transmit large torque, hence used in heavy vehicles like trucks. Larger diameter of gears can transmit greater torque but at the same time it will require greater space.