Suspension and Steering Flashcards
Ride
Isolate translation and rotation from external influences to maintain comfortable ride for passengers
Handling
Maintain tyre contact with road surface
Coil Spring
High strength steel (>1000MPa)
Leaf Spring
Typically high strength steel, composite in some modern applications (glass fibre and epoxy)
Torsion Bar
High strength steel splined at the ends
Air Spring
Two cylinders filled with air that provide cushion
Koni Shock absorbers
Mono-tube with high pressure gas or twin tube with low pressure gas
Ball joints
Steel/steel contact gives the closest displacement transfer but also transmits vibrations.
Rubber Bushings give the best Noise vibration and harshness level but also have the best compliance
Constant Velocity Joint
Uses balls to transfer torque and provide articulation up to 47 deg. higher installation angles reduce efficiency
McPherson Strut
Most widely used front suspension system. Can also be used in the rear eg Porsche Boxter
Double wishbone/ Short Long Arm
Common in high performance applications. Lower wishbone arm is longer than top arm
uses coil spring
Hotchkiss
Used on Driven rear axle systems.
Leaf spring
Dead axle
Differential fixed to the chassis
Twistbeam
Low cost
Lightweight
for small FWD cars only
Solid bar between two coil springs at either wheel
McPheason Strut
Can be used on any drive configuration
Gives more independence than a twist beam.
Consists of coil spring and 3 bars
SLA Double wishbone
Can be used on any drive configuration
Gives more precise wheel control over strut
Multi link
Ultimate Suspension layout - has optimum wheel control
Steering Mechanism
Rack and pinion for most cars however some luxury vehicles use a recirculating ball method
Power Steering
Provided by an electric motor in new vehicles due to the need for lane assist
Used to be hydraulic
Steering Column Design
Required to fold/compress in a crash so that it doesn’t become a spear into driver or passengers
Electric Power Steering
Rack is driven by an electric motor.
Based on a computer controlled feedback circuit which supplies power to the motor depending on the torque and speed sensed.
