Gears & Spline Shafts Sharif Ali What are they? What are they used for?

Gears A Brief History Began as wood with pegs and used animal fat grease as lubrication Used in wind and water wheel machinery and to power textile machinery

Gears Uses  Three main uses: To change the rate of rotation of a machinery shaft To change the direction of the axis of rotation To change between rotary and linear motion

Gears Example 1 Spur Gears Rate of Rotation Most common type of gear Straight teeth, parallel shafts Can be used to create large gear reductions Used in oscillating sprinkler, wind up alarm clock, washing machine and clothes dryer Loud due to teeth collision

Spur gears

Gears Example 2 Helical Gears Much more quiet and smooth than spur gears due to the angled cut of the teeth Can be mounted on perpendicular shafts to adjust angle of rotation by 90 o Used in most car transmissions

Helical Gears

Gears Example 3 Worm Gears Used when large gear reductions are needed Worm can turn gear but gear cannot turn worm Useful in conveyor systems

Gears Example 4 Rack & Pinion Gears Rotation into Linear Used in the steering system on automobiles Also used on same scales

Spline Shafts Grooves or tongues are machined along the length of the shaft This allows for both the shaft and another corresponding shaft or component to rotate together

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