ZBL-08 "Snow Leopard" - Suspension
The first two axles of the VNl wheeled infantry fighting vehicle abandoned the WZ551 double wishbone independent suspension design and adopted the MacPherson suspension (also called the sliding column swing arm independent suspension). This suspension usually consists of two basic parts: strut-type shock absorber and A-shaped lower arm. The reason why it is called a strut-type shock absorber is that in addition to damping, it also supports the entire body, but its structure is extremely compact.
The shock absorber and the damping spring are integrated to form a sliding column that can move up and down. The lower arm is usually an A-shaped design, which is used to provide partial lateral support to the wheel and to withstand all the front and rear stress.
The weight of the entire car body and all the impacts of the wheels during movement are borne by these two components. Compared with the WZ551 double wishbone independent suspension, the Macpherson independent suspension has reduced an A-shaped upper arm; and the WZ523 unequal-length double wishbone independent suspension shock absorber and torsion bar split, the Macpherson independent suspension shock absorber and suspension elastic element are integrated.
The advantage of MacPherson independent suspension is that the structure is simple and compact, so that the suspension is light in weight and small in space. As is well known, vehicle suspension systems are moving parts. The lighter the moving parts, the faster the response speed and rebound speed of the suspension, and the stronger the shock absorption effect, which can further increase the vehicle ride under the condition of a certain body weight. This improves the comfort of personnel. The direct benefit of the small footprint is that the designer can arrange a larger engine in the engine compartment, and the placement method can also be arbitrary. Based on this effect, the German "Boxer" wheeled vehicle simply adopted a more compact engine horizontal layout to increase the requirements for the vehicle's modular design and load space.
In addition, the Macpherson type is a suspension form composed of a hinged strut and a lower cross arm. The shock absorber can double as the steering kingpin, and the steering knuckle can rotate around it. The characteristic is that the position of the kingpin and the positioning angle of the front wheel change with the up and down movement of the wheel, which is the opposite of the candle suspension. This kind of suspension has simple structure, compact layout, small changes in front wheel positioning, and good driving stability. It is selected as the front axle suspension by most wheeled combat vehicles. The earliest ground weapon using this suspension device is the "Piranha" wheel. Type armored car family.
The disadvantage of this suspension is: because the shock absorber and the shock absorber spring act as the kingpin, and at the same time bear the lateral force of the ground acting on the wheel, the resistance is greater when moving up and down, and the wear increases; when When making a sharp turn, due to the side tilt of the body, the left and right wheels also tilt to the outside, resulting in understeer. The softer the spring, the greater the tendency. Therefore, this suspension has higher requirements on the manufacturing process of the A-shaped lower support arm and the shock-absorbing spring. However, it is trustworthy that the suspension spring of the VNl wheeled infantry fighting vehicle is an adjustable oil-air spring.
As for the oil-gas spring suspension, the Japanese TK-X new main battle tank, which was exposed earlier this year, became famous because of the oil-gas spring suspension. So what are the advantages of oil-air spring suspension? As we all know, there are generally five types of suspension used in ground vehicles: torsion bar springs, leaf springs, coil springs, air springs and oil-air springs. Among them, torsion bar springs and leaf springs are known for their sturdiness and reliability, but their disadvantage is that they take up a lot of space in the vehicle. The main advantages of the coil spring are small size, strong variable stiffness, and large suspension stroke. The disadvantage is that the coil spring only has a buffering effect.
When used as a suspension element, additional guiding devices and shock absorption devices are required. The main features of the air spring are similar to the spiral spring, except that the suspension stroke is larger and the system consists of an oil-air spring and a flow distribution system. The oil-air spring uses gas as an elastic element and introduces oil between the gas and the piston as an intermediate medium; while the distribution system uses the flow of oil to balance axle load, damping vibration, and adjust vehicle height.
The biggest advantage of the hydro-pneumatic suspension system is that it can play the role of multi-axis balance, and can increase the vehicle's roll stiffness, overcome the braking forward tilt (especially important for vehicles with MacPherson suspension), adjust the height of the frame and lock Dead suspension. Therefore, the cross-country maneuverability and driving comfort of the vehicle using the hydro-pneumatic suspension system are optimal, but its disadvantage is that the reliability of the hydro-pneumatic spring element is heavily dependent on the precision of the manufacturing process.
In addition, the fatal flaw of the oil-air spring is that any suspension terminal is damaged, which will cause the suspension system of the vehicle to lose function. Therefore, even if the Germans have the best machining technology in the world, their conservative and demanding nature made them give up the excellent oil-gas spring suspension when designing the "Boxer" wheeled armored vehicle. However, in view of the many advantages of hydro-pneumatic springs, the new generation of wheeled vehicles such as the French VBCI, the Swiss "Piranha" IV and the Finnish AMV all use the hydro-pneumatic suspension.
Of course, in order to overcome the shortcomings of the oil-air spring, designers often use the air-air hybrid suspension, or install a spiral spring suspension outside the oil-air spring suspension as an occasional need. China's PLZ89 122mm self-propelled howitzer uses the former. Most wheeled combat vehicles usually choose the latter. Presumably the VNl wheeled infantry fighting vehicle is no exception. It can be seen that the suspension device of China's VNl wheeled infantry fighting vehicle has a world-class standard.
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