The car suspension is an important part of the ride comfort. At the same time, the car suspension is used as a force-transmitting mechanism for connecting the frame (or body) with the axle (or wheel), and it is also an important component to ensure the safety of the car. Therefore, car suspensions are often listed as important specifications for the car's technical specifications, as one of the indicators to measure the quality of cars.

Each wheel is individually mounted on the body or axle by a suspension. The axle is disconnected and the middle section is fixed to the frame or the body; the two sides of the suspension are not affected by the impact, and due to the suspension quality Lighter; cushioning and shock absorbing ability, comfortable ride. The indicators are superior to the non-independent suspension, but the suspension structure is complicated and the drive axle and steering system are complicated. There are two types of vehicles that use this type of suspension.

1) The wheels on both sides can move independently without affecting each other;

2) The non-sprung mass is reduced, which is beneficial to the smoothness of the car;

3) The use of the disconnected axle can reduce the engine position and reduce the center of gravity of the vehicle;

4) The wheel has a large space for movement, which can reduce the stiffness of the suspension and improve the ride comfort.

Cross arm suspension

1 . Single wishbone independent suspension

It is characterized in that when the suspension is deformed, the wheel plane will be inclined to change the distance between the wheels on both sides and the contact point of the road surface - the wheel track, causing the tire to slip laterally with respect to the ground, damaging the adhesion of the tire and the ground. In addition, when the suspension is used for the steering wheel, the main pin inclination angle and the wheel camber angle are greatly changed, which has a certain influence on the steering operation, and thus is rarely used in the front suspension. as the picture shows.

2 . Double wishbone independent suspension

The upper and lower swing arms are not equal in length, and the length ratio is appropriate, so that the angle and the track of the wheel and the king pin do not change much. This independent suspension is widely used on the front wheels of cars. The arms of the double cross arms are formed in an A-shape or a V-shape. The upper and lower V-shaped swing arms of the V-arm are mounted on the wheel at a certain distance and the other end is mounted on the frame.

The upper arms of the unequal arms are shorter than the lower arms. When the car wheel moves up and down, the upper arm moves less than the lower arm. This will cause the upper part of the tire to move slightly inside and outside, while the bottom has little effect. This structure helps to reduce tire wear and improve ride comfort and directional stability.

1 . Single trailing arm independent suspension

If the steering wheel uses a single trailing arm type independent suspension, the up and down of the wheel will cause a large change in the caster's caster angle. Therefore, the single trailing arm type independent suspension is generally used for the rear wheel that does not turn.

Classified by wheel movement, the rear suspension of the Fukang sedan is a single trailing arm torsion bar spring independent suspension. Figure 4 shows.

The rear suspension of Santana and Jetta has the same structure and is also a single trailing arm independent suspension. It has an integral V-shaped cross-section beam with welded cross-section tubular longitudinal arms at both ends to form an integral frame - the rear axle body. The front end of the trailing arm is hingedly connected to the body by a rubber-metal support. The rear end of the trailing arm is connected to the hub and the damper. When the car is running, the wheel and the rear axle body swing up and down with the rubber-metal support as the fulcrum, which is equivalent to the single trailing arm type independent suspension. When the deformation of the suspension on both sides is not equal, the V-shaped cross member of the rear axle body is torsionally deformed, and the transverse beam has a role as a lateral stabilizer due to the greater elasticity of the beam. Unlike conventional non-independent suspensions with integral shafts, the bounce of one side wheel directly affects the other side of the wheel. Therefore, the suspension is also called a longitudinal arm torsion beam type independent suspension.

2 . Double trailing arm independent suspension

The lengths of the two longitudinal arms of the double trailing arm type independent suspension are generally made equal to form a parallel four-bar linkage. When the wheel is bouncing up and down, the caster's caster angle remains the same, and this form of suspension is suitable for the steering wheel.

2.3 Suspension of the wheel moving along the kingpin

1 . Candle suspension

The advantage is that when the suspension is deformed, the positioning angle of the kingpin does not change, and only the wheelbase and the wheelbase are slightly changed; it is beneficial to the steering behavior and driving stability of the automobile. The disadvantage is that the lateral force is completely absorbed by the sleeve and the main pin, and the frictional resistance between the two is large and the wear is severe. Therefore, this type of structure is currently rarely used.

2 . McPherson suspension (sliding arm or strut type, etc.)

The MacPherson suspension is currently the most popular suspension structure for front-mounted front-drive cars and some light-duty passenger cars. The barrel damper is a sliding column, the inner end of the yaw arm is connected to the vehicle body through a hinge, and the outer end is connected to the steering knuckle through a ball hinge. The upper end of the damper is connected to the vehicle body, and the lower end of the damper is connected to the knuckle. The lateral force of the wheel is mostly received by the yaw arm, and the rest is received by the damper piston and the piston rod. The connection between the center of the hinge on the barrel damper and the center of the ball hinge at the outer end of the yaw arm is the main pin axis, and this structure is also a structure without a king pin.

2.4 Single inclined arm independent suspension

The structure of the single inclined arm type independent suspension is between the single cross arm and the single trailing arm, and is mostly used for the rear suspension of the rear wheel drive automobile.

2.5 multi-rod independent suspension

Coil springs are often used in the independent suspension, so that for the lateral force, the vertical force and the longitudinal force, a guide is required to receive and transmit these forces. Therefore, in some cars, a multi-rod suspension is used to reduce the weight and simplify the structure. As shown in Figure 10. The upper link bracket is connected to the vehicle body (or the frame), and the outer end of the upper link is connected to the third link. Rubber vibration isolating sleeves are attached to both ends of the upper rod. The lower end of the third link is connected to the steering knuckle by a heavy thrust bearing. The lower link 5 is the same as the ordinary hem arm, and the inner end of the lower link is connected to the front beam through a rubber vibration isolating sleeve. The ball joint connects the outer end of the lower link to the steering knuckle. The kingpin axis of the multi-barrel front suspension system extends from the lower ball joint to the upper bearing, which is independent of the upper link and the third link. The multi-rod suspension system has good steering stability and reduces tire wear. This suspension damper and coil spring do not rotate along the knuckle like the MacPherson suspension.