Silverado Classic SS V8-6.0L (2007)
Torsion Bar: Description and Operation
General Description (Torsion Bar)
The front suspension has 2 primary purposes:
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Isolate the driver from irregularities in the road surface.
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Define the ride and handling characteristics of the vehicle.
The front suspension absorbs the impact of the tires travelling over irregular road surfaces and dissipates this energy throughout the suspension
system. This process isolates the vehicle occupants from the road surface. The rate at which the suspension dissipates the energy and the amount of
energy that is absorbed is how the suspension defines the vehicle's ride characteristics. Ride characteristics are designed into the suspension system
and are not adjustable. The ride characteristics are mentioned in this description in order to aid in the understanding of the functions of the suspension
system. The suspension system must allow for the vertical movement of the tire and wheel assembly as the vehicle travels over irregular road surfaces
while maintaining the tire's horizontal relationship to the road.
This requires that the steering knuckle be suspended between an upper and a lower control arm. The lower control arm attaches from the steering
knuckle at the outermost point of the control arm. The attachment is through a ball and socket type joint. The innermost end of the control arm is
attached at 2 points to the vehicle frame through semi-rigid bushings. The upper control arm attaches to the frame in the same fashion. Attached to the
lower control arm is a torsion bar. Torsion bars are steel or steel composite shaft that connects from the lower control arm an adjustable mount at the
torsion bar crossmember. The torsion bar functions as a spring in this suspension system. The torsion bar absorbs energy from irregular road surfaces
by twisting force along the center axis. The torsion bar has a resistance to this twisting motion and will return to the original, at-rest position similar to
that of a spring.
A shock absorber is used in conjunction with this system in order to dampen out the oscillations of the torsion bar. A shock absorber is a basic
hydraulic cylinder. The shock is filled with oil and has a moveable shaft that connects to a piston inside the shock absorber. Valves inside the shock
absorber offer resistance to oil flow and consequently offer resistance to rapid movement of the piston and shaft. Each end of the shock absorber is
connected in such a fashion in order to utilize this recoil action of a torsion bar alone.
Front suspension systems utilize a stabilizer shaft. The stabilizer bar connects between the left and right lower control arm assemblies through the
stabilizer link and stabilizer shaft insulators. This bar controls the amount of independent movement of the suspension when the vehicle turns.
Limiting the independent movement defines the vehicle's handling characteristics on turns.
