Motion Transformation Systems CH 13 Mechanical Engineering

Motion transformation systems Motion transformation systems relay motion from one part to another while changing the type of motion Rotation  Translation or Translation  Rotation Reversibility= Translational or rotational movement can be driver or driven.

Rack and Pinion Rotation  Translation or Translation  Rotation Reversible Teeth on rack + pinion must be identical Needs lubrication to prevent wear Greater # of teeth on pinion = slower rotation

Examples

Screw Gear Systems Rotation  Translation Type 1: Type 2: Not Reversible Type 1: Screw is the driver Rotation of the screw makes the nut do a translation Nut cannot rotate Type 2: Nut is the driver Rotation of the nut causes the screw to translate Nut can rotate

Cam and Follower Systems (Eccentrics) Rotation  Translation Not reversible Cam rotates and the follower has translational motion Shape of cam determines how the follower moves An eccentric is a special cam where the rotational axis is off-center

Slider-Crank Mechanisms Rotation  Translation or Translation  Rotation Reversible Cylinder guides translation Requires frequent lubrication Crank Piston Connecting rod

Examples Combustion engine Steam train