01-10-2012, 12:40 PM
Suspension Design Case Study
Suspension Design.ppt (Size: 866 KB / Downloads: 249)
Purpose
Suspension to be used on a small (lightweight) formula style racecar.
Car is intended to navigate tight road courses
Surface conditions are expected to be relatively smooth
Performance Design Parameters
For this case the main objective is to optimize mechanical grip from the tire.
This is achieved by considering as much tire information as possible while designing the suspension
Specific vehicle characteristics will be considered.
Considerations
Initially the amount of suspension travel that will be necessary for this application must be considered.
One thing that is often overlooked in a four wheeled vehicle suspension design is droop travel.
Depending on the expected body roll the designer must allow adequate droop travel.
Components
Upper A-arm
The upper A-arm serves to carry some of the load generated on the suspension by the tire.
This force is considerably less then the load carried by the lower A-arm in a push rod set-up
The arm only has to provide a restoring force to the moment generated by the tire on the lower ball joint
Live Vs. Fixed Spindle Advantages and Disadvantages
Live Spindle :
Less parts
Lighter weight if designed correctly
More wheel offset
Bearing concerns
Retention inside of the upright assembly
Fixed spindle
Simple construction
Hub sub-assembly
Spindle put in considerable bending
More components, and heavier
Defining Camber
Once we set our static camber we must adjust our dynamic camber curves
This is done by adjusting the lengths of the upper and lower A-arms and the position of the inboard and out board pivots
These lengths and locations are often driven by packaging constraints