Gears and Spline Shafts Francesca Ferzoco Objectives To introduce the main types of gears and spline shafts that might be seen on work terms To explain the functions of gears and spline shafts

Gears: Functions They provide a gear reduction in motorized equipment 1.To reverse the direction of rotation 2.To increase or decrease the speed of rotation 3.To move rotational motion to a different axis 4.To keep the rotation of two axes synchronized

Gears The gear ratio is determined by the distances from the center of the gear to the point of contact Many modern gears use a special tooth profile called an involute The pitch diameter is the effective contact diameter An involute profile gear tooth produces a constant ratio of rotational speed

Gears: Main Types Spur Gears Helical Gears Crossed Helical Gears

Gears: Main Types Bevel Gears Spiral Bevel Gears Hypoid Gears

Gears: Main Types Worm Gears Rack and Pinion Gears

Spline Shafts Have either grooves or tongues machined along its length The mating bearings run along either the groove or tongue, providing high rigidity Spline Bushing Bearing Ball Spline Bearing Spline Shafts: Main Types

Summary Gears: Functions 1.To reverse the direction of rotation 2.To increase or decrease the speed of rotation 3.To move rotational motion to a different axis 4.To keep the rotation of two axes synchronized Gears: Main Types  Spur Gears  Helical Gears  Bevel Gears  Hypoid Gears  Worm Gears  Rack and Pinion Gears Spline Shafts: Main Types  Spline Bushing Bearing  Ball Spline Bearing

References m/gear.htm Specifications/Mechanical_Co mponents/Bearings_Bushings/L inear_Guides_Rails