Suspension Systems Flashcards
What are the two types of frames that are used in vehicle construction today
Conventional Frame Construction
Unibody Construction
What is the basic function of the Springs?
absorbs shock forces while maintaining correct riding height
What is spring rate?
The amount of deflection exhibited under a specific load.
The amount of load necessary to deflect the spring 25.4 mm or 1 inch
What is jounce?
occurs when a wheel hits a bump and moves up.
What is rebound?
Occurs when a wheel hits a dip or hole and moves downward
What is the role of the shock absorber?
to dampen and stop the motion of the spring after jounce
What is sprung weight?
the vehicle’s weight supported by the suspension system. Ex. body, frame, engine, transmission, etc…
What is unsprung weight?
the weight of the components not supported by the springs. Ex. steering knuckles, rear axle assemblies, etc…
What are linear rate coil springs?
coil springs that have one basic shape and a consistent wire diameter.
What are variable rate coil springs?
Coil springs that are characterized by a combination of wire sizes and shapes.
What are cargo coils?
variable rate springs with a consistent wire diameter and unequally spaced coils.
How do consistent wire diameter progressive rate coils work?
At stationary loads, the inactive coils are supporting all the vehicle’s weight. As the load increases, the transitional coils take over until they reach maximum capacity. Finally the active coils carry the remaining overload. - Allows for automatic load adjustment while maintaining vehicle height.
How do variable wire diameter progressive rate coils work?
The active coils have a large wire diameter and the inactive coils have a small wire diameter.
What are the three types of leaf springs?
multiple leaf
monoleaf
fibre composite
What are the characteristics of multiple leaf springs?
- Flat steel leaves that are bundled together and held together with clips or a bolt.
- The farther the spring deflects, the stiffer it gets.
- The more leaves, the stronger the spring
- The thicker and shorter the leaves, the stronger the spring
- The ends of the leaves slide over one another as the spring flexes creating friction and noise.
What are the characteristics of Monoleaf springs?
- Usually have a heavy or thick centre section that tapers off at both ends.
- Provides a variable spring rate and a smooth ride
- Does not produce noise or friction
What are the characteristics of Fibre Composite springs?
- Incredibly lightweight
- Smoother riding, better handling and faster responding suspension
- Reduces the sprung mass of the suspension which reduces the spring effort and amount of shock control required to keep the wheels in contact with the road.
What are the characteristics of Air Springs?
- Uses air to provide a comfortable street ride with automatic front and rear load levelling.
- Consists of a reinforced rubber bag pressurized with air
What are torsion bars?
A straight spring that twists and straightens out to absorb up and down movement. They are directional and are usually marked left and right.
How do torsion bars work?
One end is attached to the frame and the other end is attached to the lower control arm. As the lower control arm moves up and down, the torsion bars twists.
What are shock absorbers?
Hydraulic cartridges that dampen spring movement. They prevent uncontrollable bounce. The faster they move, the more resistance they have.
What types of shocks are there?
Conventional (double-tube) Monoshock (single tube) Gas-charged monoshock Manual fill air shock Automatic load levelling air shock
How does a shock work?
Under compression, the piston rod moves downward in the shock. The piston pushes on the oil in the chamber which presses on the dividing piston and compresses the gas chamber. When the shock rebounds, the gas pressure returns the dividing piston back to it’s original location. The valves in the shock control the rate of compression (jounce) and rebound
What is shock absorber ratio?
The proportion of a shocks ability to resist jounce (compression) and rebound.
Indicated by percent jounce / percent rebound
