Car suspension is an important component to ensure ride comfort. At the same time, the automobile suspension is used as a force transmission mechanism for connecting the frame (or body) and the axle (or wheel), and it is also an important part to ensure the safety of the car. Therefore, the automobile suspension is often listed as an important component in the technical specifications of the car, as one of the indicators to measure the quality of the car.
Wishbone independent suspension 1. Single wishbone independent suspension Its characteristic is that when the suspension deforms, the wheel plane will be inclined to change the distance between the wheels on both sides and the road contact point—the wheelbase, causing the tire to slide laterally with respect to the ground and destroy the adhesion of the tire to the ground. In addition, when this kind of suspension is used for steering wheels, the camber angle of the king pin and the camber angle of the wheel will change greatly, which will have a certain impact on the steering operation, so it is rarely used in the front suspension.
2. Double wishbone independent suspension The upper and lower swing arms are not equal in length, and the proper length ratio is selected to make the angle of the wheel and the king pin and the track distance change little. This independent suspension is widely used on the front wheels of cars. The arms of the double wishbone are made into A-shape or V-shape. The upper and lower V-shaped swing arms of the V-shaped arm are respectively mounted on the wheels 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 wheels move up and down, the arc of the upper arm is smaller than that of the lower arm. This will cause the upper part of the tire to move slightly inside and out, while the bottom effect will be minimal. This structure is conducive to reducing tire wear and improving automobile ride comfort and directional stability. As shown in Figure 3.
Trailing arm independent suspension 1. Single trailing arm independent suspension If the steering wheel adopts a single trailing arm independent suspension, the wheel bouncing up and down will cause a large change in the caster angle of the kingpin. Therefore, the single trailing arm independent suspension is generally used for non-steering rear wheels.
2. Double trailing arm independent suspension The two trailing arms of a double trailing arm independent suspension are generally made equal in length to form a parallel four-link mechanism. When the wheels bounce up and down, the caster angle of the king pin remains unchanged. This type of suspension is suitable for steering wheels. 1. Candle suspension The advantage is that when the suspension is deformed, the positioning angle of the king pin will not change, only the wheelbase and wheelbase will be slightly changed; it is beneficial to the steering maneuverability and driving stability of the car. The disadvantage is that the lateral force is all borne by the sleeve and the king pin, the frictional resistance between the two is large, and the wear is serious. Therefore, this structure is rarely used at present.
2. Macpherson type suspension (slider type or arm type) The Macpherson suspension is a suspension structure that is more common in front-drive cars and some light passenger cars. The cylindrical shock absorber is a sliding column. The inner end of the swing 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 shock absorber is connected to the vehicle body, and the lower end of the shock absorber is connected to the steering knuckle. Most of the lateral forces received by the wheel are borne by the swing arm, and the rest are borne by the shock absorber piston and 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 swing arm is the main pin axis. This structure is also a no-pin structure.
The structure of a single inclined arm independent suspension is located between a single cross arm and a single trailing arm, and is mostly used on the rear suspension of a rear wheel drive vehicle.
Coil springs are mostly used in independent suspensions, so for lateral forces, vertical forces and longitudinal forces, a guide device is required, that is, rods are used to bear and transmit these forces. Therefore, some cars use multi-rod suspensions to reduce vehicle weight and simplify structure. The multi-rod suspension system has good handling stability and can reduce tire wear. This suspension shock absorber and coil spring do not turn around the knuckle like the Macpherson suspension.
Each wheel is individually mounted on the body or axle through a set of suspensions. The axle is disconnected and the middle section is fixed to the frame or body. The wheels on both sides of this suspension do not affect each other when impacted, and because of the suspension quality Lighter; strong cushioning and shock absorption, comfortable ride. All indicators are better than non-independent suspension, but the suspension structure is complicated and it will also complicate the drive axle and steering system. The following two types of vehicles use this suspension. 1) The wheels on both sides can move independently without affecting each other; 2) The unsprung mass is reduced, which is good for the ride comfort of the car; 3) The use of disconnected axles can lower the position of the engine and the center of gravity of the entire vehicle; 4) Large wheel movement space can reduce suspension stiffness and improve ride comfort.