Motion Transformation Systems CH 13 Mechanical Engineering Motion

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

Cam and Follower Systems (Eccentrics) � Rotation � Not � Cam Translation reversible 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 offcenter

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

Examples � Combustion � Steam train engine