Differential Dissection: Gears and Spline Shafts J. MacCaull To impart a basic understanding of differentials and a knowledge of gears and spline shafts in differentials

What are differentials? Mechanical devices Used commonly in wheeled vehicles Provide power to the wheels Allow wheels to rotate at different speeds

Why are differentials useful? When a car turns, the inside wheels spin more slowly than the outside wheels The driven wheels are linked Without a differential the wheels must spin at the same speed Turning is HARD without differentials

How do differentials work? They use GEARS to split the engine torque GEARS are mounted on SPLINE SHAFTS

Differential Gears Differential gears have two coaxial gears – PINIONS and the TURNTABLE Pinions are mounted on shafts Shafts are connected to turntable

Gear Types Spiral Pinion gears contact ring gear at its centreline Teeth are curved and oblique Transmit power to perpendicular shafts Hypoid Pinion gears contact ring gear below its centreline They operate on non-intersecting axes

THERE ARE MANY OTHER TYPES OF GEARS!

Hypoid Gear

SPLINES Unlike gears, they only apply transmission of power on the same axes Most splines are used for mounting gears Ends of shafts have teeth for the gears to fit between

Summing Up Differentials allow driven wheels to rotate at different speeds This is done by using gears There are many gear types Splines are used to mount gears

Conclusion Now you know what a differential is and what it does Now you know what gears do in a differential Now you know what spline shafts do in a differential

More Information http://auto.howstuffworks.com/differential.htm http://en.wikipedia.org/wiki/Differential_gear http://www.gears-manufacturers.com/differential-gears.html http://www.arrowgear.com/products/custom_gearing.htm