The types of suspension axles are mainly divided into independent suspension axles and non independent suspension axles. The following are the specific structures and characteristics of these two types of axles:
Independent suspension axle
The independent suspension axle is divided into two sections, and each wheel is independently installed under the frame with a coil spring. When one wheel bounces, the other wheel is not affected, and the vibration of the car body is greatly reduced, thereby improving the stability and comfort of the car, especially when driving on high-speed roads. However, this suspension structure is more complex and has a lower load-bearing capacity, which can also make the car’s drive and steering systems more complicated. Independent suspension axles can be divided into the following types:
Cross arm suspension axle:
Structure: The wheels swing in the transverse plane of the car, and are divided into double wishbone and single wishbone suspension systems according to the number of wishbones.
Characteristics: The single wishbone type has the advantages of simple structure, high roll center, and strong anti roll ability. However, with the increase of modern car speed, its disadvantages have gradually become apparent, such as large changes in wheelbase and increased tire wear when the wheels bounce. The double wishbone suspension system optimizes the length and arrangement of the upper and lower wishbones to ensure that the changes in wheelbase and front wheel alignment parameters are within acceptable limits, ensuring good driving stability of the vehicle. Among them, the double wishbone suspension is widely recognized as the most excellent in handling, and the vast majority of performance sports cars and even F1 racing cars use the double wishbone suspension structure.
Longitudinal arm suspension axle:
Structure: The wheels swing in the longitudinal plane of the car, divided into two forms: single longitudinal arm and double longitudinal arm.
Features: The longitudinal arm suspension axle is suitable for large cars and trucks and can withstand large loads.
Multi link suspension axle:
Structure: Multiple rods are combined to control the position changes of the wheels.
Features: The multi link suspension axle can make the changes in wheelbase and toe in very small when the wheels bounce, and the car can smoothly turn according to the driver’s intention regardless of whether it is in driving or braking state. However, there is a phenomenon of axle sway when the car is driving at high speeds.
Candlestick suspension axle:
Structure: Adopting a bracket shaped like a candle holder, the wheels move along the main axis direction.
Features: The characteristic of candle suspension axle is that the main pin position and front wheel alignment angle do not change with the up and down jumping of the wheels, which is beneficial for the handling and stability of the car.
MacPherson suspension axle:
Structure: Composed of spiral springs, shock absorbers, and triangular lower swing arms, most models also add a lateral stabilizer bar.
Features: The MacPherson suspension axle is one of the most widely used front suspensions for cars in the world today, with advantages such as compact structure, small changes in front wheel alignment parameters when the wheels bounce, and good handling stability. However, due to its straight tube structure, it lacks resistance to impacts in the left and right directions, resulting in poor resistance to braking and nodding.
Non independent suspension axle
The wheels of non independent suspension axles are installed at both ends of a single axle. When one wheel bounces, it affects the other wheel to also bounce, causing the entire vehicle to vibrate or tilt. This suspension system has poor stability and comfort for cars, but due to its simple structure and high load-bearing capacity, some sedans still use this type of rear suspension, which is widely used in the front and rear suspensions of trucks. Non independent suspension axles can be divided into the following types:
Torque beam axle:
Structure: A common non independent suspension system suitable for economical and commercial vehicles.
Features: The torsion beam axle has a simple structure, low cost, high strength, and easy maintenance, but its comfort and handling stability are relatively poor.
Torque beam suspension axle:
Structure: Install the wheels on the axle.
Features: The torsion beam suspension axle also has the characteristics of simple structure and high bearing capacity, suitable for large cars and trucks.
Parallel leaf spring suspension axle:
Structure: Parallel leaf springs are used to connect the wheels and frame.
Features: The parallel leaf spring suspension axle not only alleviates the impact from the road surface, but also maintains the axle in a certain position, so no special device is needed to support the axle, making the vehicle structure relatively simple. However, due to the fact that the driving force, braking force, and centrifugal force generated by the wheels during turning are all transmitted to the vehicle body through springs, softer springs cannot be used. This suspension system is suitable for off-road vehicles and SUVs.