1. Motion Transformation Systems
CH 13 Mechanical Engineering

2. 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.

3. 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

4. Examples

5. 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

6. 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

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

8. Examples
Combustion engine
Steam train