Contents: Front suspension ↧ Frame ↧
Front suspension
The front suspension performs 2 main tasks:
- Insulates the driver from uneven road surfaces.
- Determines the driving performance and controllability of the vehicle.
The front suspension absorbs the impact of the tires when driving over rough road surfaces and dissipates this energy by transmitting it to the suspension system. This process isolates the occupants of the vehicle from the road surface. The speed at which the suspension dissipates energy and the amount of energy absorbed are indicators of how the suspension determines the ride quality of the vehicle. Ride quality is built into the design of the suspension system and is not adjustable. Ride quality is discussed in this description to help understand the function of the suspension system. The suspension system must allow vertical movement of the tire and wheel assembly as the vehicle travels over rough road surfaces while maintaining horizontal contact between the tire and the road.
This requires that the steering knuckle be suspended between the lower control arm and the strut assembly. The lower control arm is attached to the steering knuckle at the outermost point of the control arm. The attachment is made by means of a ball joint. The outermost inner end of the control arm is attached at 2 points to the vehicle frame by means of semi-rigid bushings. The upper part of the steering knuckle is attached to the strut assembly. The strut assembly is then attached to the vehicle body by means of the upper bearing. The steering knuckle can move up and down, regardless of the design of the vehicle body and frame.
This up and down movement of the steering knuckle as the car goes over bumps is absorbed primarily by a coil spring. This spring is held taut by a telescopic strut assembly. The strut is used in conjunction with this system to dampen the oscillations of the coil spring. The strut is a rudimentary hydraulic cylinder. The strut is filled with oil and has a movable rod that is connected to a piston inside the strut. Valves inside the shock absorber resist the flow of oil and as a result slow down the rapid movement of the piston and rod. Each end of the shock absorber is connected in such a way as to use this return action of a single spring. Each end of the strut is designed as a connection point of the suspension system to the car and acts as a support cup for the coil spring. This allows the strut to use a damping action to reduce the recoil of the spring itself. The lower control arm is capable of vertically rotating on the frame of the car. A ball joint allows the steering knuckle to maintain a perpendicular connection to the road surface. In front suspension systems, a stabilizer bar is used. The stabilizer bar connects the left and right strut assemblies via the stabilizer link and stabilizer bar insulators. This bar controls the amount of independent movement of the suspension when the vehicle turns. The limitation of independent movement determines the vehicle's handling in turns.
Frame
The front frame is a full perimeter frame assembly with four corner insulated mounts to the body, providing isolation of the vehicle occupants from road impacts and noise and vibration from the powertrain (in combination with various supports).
The front frame, using a 4-post system, distributes and supports the weight of the powertrain, front suspension and steering components so that they can be correctly configured, assembled and operated.
The front frame also contributes to the overall structural stability and strength of the vehicle/front section/rear section, acts as a structural member in a collision, and is responsible for energy management and minimizing energy transfer to the body structure during impacts with obstacles.