Suspension is a general term for all force-transmitting connection devices between the frame (or load-bearing body) of an automobile and the axle (or wheel), and its role is to transmit the force and torque between the wheel and the frame, and It cushions the impact force transmitted from the uneven road to the frame or body, and reduces the vibration caused by it to ensure that the car can run smoothly.
A typical suspension structure is composed of elastic elements, a guide mechanism, and a shock absorber. Some structures also include buffer blocks and lateral stabilizer bars. Elastic components come in the form of leaf springs, air springs, coil springs and torsion bar springs, while modern car suspensions mostly use helical springs and torsion bar springs, and some premium cars use air springs.
Dependent suspension
The structure of a non-independent suspension is that the wheels on both sides are connected by an integrated axle, and the wheels and the axle are suspended under the frame or the body through an elastic suspension. Non-independent suspensions have the advantages of simple structure, low cost, high strength, easy maintenance, and small changes in front wheel positioning during driving, but due to their poor comfort and handling stability, they are basically no longer used in modern cars. , Mostly used in trucks and buses.
Leaf spring type independent suspension The leaf spring is used as an elastic element of a non-independent suspension. Because it also serves as a guide mechanism, the suspension system is greatly simplified. A vertical leaf spring non-independent suspension adopts a leaf spring as an elastic element and is a suspension arranged on a car in parallel with a longitudinal axis of the car.
Classification: Vertical leaf spring non-independent suspension can be divided into asymmetric vertical leaf spring non-independent suspension, balanced suspension, and symmetrical vertical leaf spring non-independent suspension. The latter is the latter when not specified, and is referred to as the abbreviation. Non-independent suspension for vertical leaf springs.
Spiral spring type non-independent suspension Because the coil spring is an elastic element and can only support vertical loads, the suspension system needs to be equipped with a guide mechanism and a shock absorber.
Air spring type independent suspension Due to changes in load and road surface when the car is traveling, the stiffness of the suspension is required to change. Cars are required to reduce the height of the car on good roads and increase vehicle speed; to increase the height of car bodies on bad roads and increase capacity, so that the height of the car can be adjusted as required. Air spring-type non-independent suspensions can meet such requirements.
Oil and gas spring non-independent suspension Oil and gas spring non-independent suspension refers to the non-independent suspension when the elastic element adopts an oil and gas spring. Oil and gas springs are used in commercial trucks with large payloads, which are smaller in volume and mass than leaf springs and have variable stiffness characteristics, but they have high sealing requirements and are difficult to maintain. Hydro-pneumatic suspension is suitable for commercial trucks with high loading quality.
Independent suspension Independent suspension means that the wheels on each side are individually suspended under the frame or body by elastic suspension. Its advantages are: light weight, reducing the impact of the vehicle body and improving the ground adhesion of the wheel; softer springs with less stiffness can be used to improve the comfort of the car; the position of the engine can be lowered, and the center of gravity of the car can also be reduced, thereby Improve the driving stability of the car; the left and right wheels jump separately and are irrelevant, which can reduce the tilt and vibration of the car body. However, the independent suspension has the disadvantages of complicated structure, high cost and inconvenient maintenance. Most modern cars use independent suspensions. According to their different structural forms, independent suspensions can be divided into transverse arm, trailing arm, multi-link, candle, and Macpherson suspensions.
Cross arm Wishbone suspension refers to an independent suspension with wheels swinging in the transverse plane of the car. It is divided into double-wishbone and single-wishbone suspensions according to the number of arms.
Multi-link A multi-link suspension is a suspension in which the position of a wheel is controlled by the combination of 3-5 rods.
Trailing arm The trailing arm type independent suspension refers to a suspension structure in which a wheel swings in a longitudinal plane of a car, and is further divided into a single trailing arm type and a double trailing arm type. The single trailing arm suspension will cause a large change in the caster angle of the king pin when the wheel is jumping up and down, so the single trailing arm suspension is not used on the steering wheel. The two swing arms of a double trailing arm suspension are generally made of equal length to form a parallel four-bar structure. In this way, the caster angle of the king pin remains unchanged when the wheels bounce up and down. Double trailing arm suspensions are mostly used on steering wheels.
Candle The structural characteristics of the candle-type suspension are that the wheels move up and down along the axis of the kingpin rigidly fixed to the frame. The advantage of a candle-type suspension is that when the suspension is deformed, the positioning angle of the king pin will not change, only the wheelbase and wheelbase will change slightly, so it is particularly beneficial to the car’s steering stability and driving stability. However, the candle type suspension has a big disadvantage: that the lateral force of the car when traveling is all borne by the king pin sleeved on the king pin sleeve, which causes the frictional resistance between the sleeve and the king pin to increase, and the wear is more serious. Candlestick suspensions are not widely used.
Macphersonian The wheels of MacPherson suspension are also sliding suspensions along the king pin, but it is not exactly the same as the candle suspension. Its king pin can swing. The MacPherson suspension is swing arm and candle type. Combination of suspension. Compared with the double wishbone suspension, the advantages of the McPherson suspension are: compact structure, small changes in the front wheel positioning parameters when the wheels are bouncing, and good handling stability. The arrangement of the engine and steering system brings convenience; compared with the candle-type suspension, the lateral force on its spool has been greatly improved.
Trailing arm Towing arm suspension we call it semi-independent suspension. From the perspective of suspension classification, all suspensions can be divided into two categories, namely: independent suspension and non-independent suspension.
Active suspension The active suspension has the function of controlling the movement of the vehicle body. When the inertia of the car during braking or cornering causes the spring to deform, the active suspension will generate a force that is opposed to the inertial force, reducing the change in body position.
Suspension is an important assembly in a car. It elastically links the frame with the wheels, which is related to the various performances of the car. From the appearance, the car suspension is only composed of some rods, barrels and springs, but do not think it is simple. On the contrary, the car suspension is a car assembly that is difficult to achieve perfect requirements. This is because the suspension is not only To meet the comfort requirements of the car, and to meet the requirements of its handling stability, these two aspects are opposite to each other. For example, in order to achieve good comfort, the vibration of the car needs to be greatly buffered, so that the spring must be designed to be softer, but the softness of the spring is likely to cause the car to “nod” the brake, accelerate the “lift”, and severe left and right roll The tendency is not conducive to the steering of the car, and it is easy to cause the unstable operation of the car.