As an important part of the chassis, suspension may be more important than you think.
1. What is suspension? What does it do?
Suspension is a general term for all the force transmission connection devices between the frame (or load-bearing body) of the car and the axle (or wheel), and its role is to transmit the force and force twist between the wheel and the frame, and to buffer the impact force transmitted from the uneven road to the frame or body, and reduce the vibration caused by it to ensure that the car can drive smoothly. Suspension is actually a collective term for all the parts that connect the body and the wheels. It ensures that the body and wheels move in sync, while filtering the ground bumps that the wheels touch, so that they can be transmitted to the car as little as possible. So the suspension is the key part that determines the comfort and handling of the car. The suspension structure generally includes: springs, shock absorbers have been connected to the wheels and various connecting rods with guiding effects. Connecting rods are all kinds of things called swing arms that we commonly see.
The role of the spring is to absorb the impact from the ground, the role of shock absorption is to absorb the spring's rebound force, and all the connecting rods and swing arms are used to transmit the force received by the wheel, and can control the swing amplitude of the wheel up and down, left and right, so that the wheel moves according to the established trajectory without deviating from the direction.
What kind of suspension is a good suspension? On the one hand, the softer the springs and shock absorption, the better the absorption of bumps on the road surface, and the higher the comfort of the suspension, but the corresponding body stability will be worse, that is, the poorer the handling. On the other hand, when the vehicle changes the driving state (such as cornering or passing through bumpy roads), the smaller the spring deformation, the better the support of the body, the better the stability of the vehicle, and the better the corresponding handling, but this will affect the riding comfort. Therefore, in the vast majority of price ranges, comfort and handling are two characteristics that are forever opposed.
Second, what is the difference between independent suspension and non-independent suspension?
It is a suspension that makes each wheel independent of each other and is not affected by the run-off of the wheel on the other side. For the left and right wheels, the swing arms that connect the wheels and the body are independent and do not interfere with each other.
For example, when you can't dodge, you can only pass through a pit on one side of the wheel, if the car is four-wheel independent suspension, the roll on the side that does not go through the pit will be much lighter, and the feeling of the occupants on the car will not be very bad, of course, independent suspension also has disadvantages, because there are more parts, so the independent suspension generally occupies more space, and will increase the cost accordingly. Therefore, some complex independent suspension is more equipped on medium and large cars. The non-independent suspension is when the left and right wheels are connected to the body as a whole, and the left wheel is also passed to the right wheel when it runs. Therefore, it is often referred to as a scooter suspension.
In addition, some people renamed a semi-independent suspension. As the name suggests, it is to allow the wheels on the left and right sides to have a certain degree of free movement, but it is still not completely independent. This kind of semi-independent suspension is generally used on the rear wheel, and the wide application should be a torsion beam type (what torsion beam, towing arm are similar) semi-independent suspension.
Third, what are the advantages and disadvantages of common suspension types?
In all vehicle configuration tables, the front and rear suspension types of the car are indicated. When you look at these suspension types to get a rough idea of the car's performance orientation, you're already outstripped the vast majority of people.
1. McPherson-style independent suspension
When it comes to suspension, macpherson is bound to be bypassed. It consists mainly of a lower control arm with a triangular structure and a sliding column with a guiding effect. The lower control arm is used to control the lateral forces, while the slide column acts as cushioning, damping and guiding.
Maybe it's because it's so common, maybe it's hearsay, but in short, many friends associate McPherson with cheap.
Yes, what most people know is that even the front suspension of a common van is the McPherson suspension. But what most people don't know is that many luxury brand models have MacPhersons in the front and rear suspensions. The McPherson suspension is arguably one of the most important inventions in the automotive industry, and has been widely used since it was invented by the engineer at the time, McPherson, in the 1930s. The important thing is that the structure is simple, the space is small, and the reliability is high, so for small cars and compact cars, the front suspension will use a very cost-effective McPherson suspension. In addition, due to the small size and light weight, the "under-spring mass" that affects the handling of the car is small, so the handling is also guaranteed. Due to its structural reasons, in addition to the advantages mentioned above, it also has some congenital disadvantages.
In addition, due to the design structure of shock absorption and springs, McPherson is not suitable for wide tires, otherwise it is easy to interfere with the suspension and chew tires. In addition, the MacPherson suspension has limited lateral force. For example, you will often see that when the wheel part is hit, the car equipped with the McPherson suspension is prone to the suspension swing arm or suspension break in front. The McPherson suspension is a large branch, and many reinforced McPherson suspensions have been derived. But the basic structure is an A-arm slider structure.
2. Double wishbone independent suspension
The McPherson suspension can be seen as a single wishbones shock absorbing and spring structure, while the double wishbones, as the name suggests, have two wishbones, which are based on McPherson and have an additional upper wishbones.
Structurally, the lateral support is strengthened. And the height of the entire suspension is reduced. Therefore, it is more common in some vehicles with a focus on handling.
3. Multi-link independent suspension
The upper and lower wishbones of the double wishbones are disassembled into two connecting rods, and are not connected separately to the connecting rod and the subframe, which becomes a common multi-link independent suspension.
Because multiple connecting rods are controlled individually, this suspension is more "delicate" for road vibrations, and comfort is better, while also taking into account the handling.
The common four-link and five-link are not much different in composition, and the four-link does not include the steering link.
Multi-link structures take up a large amount of space, so they are almost only used on medium to large cars, or because most of the rear axle space is relatively rich, so it is more common on the rear wheels.
4. Double horizontal arm independent suspension
This suspension is actually a variant of the McPherson suspension — the MacPherson's A-shaped wishbones are split into two swing arms, and the springs and shocks are generally mounted on the hem arms.
Therefore, in general, the height of the double cross-arm suspension will be lower than the MacPherson suspension. And there is almost no phenomenon of tires interfering with the suspension