Types of suspensions in cars
This is on the one hand, and on the other hand, the suspension must provide, firstly, controllability, that is, be stiff enough so that the driver can control the situation, and secondly, load capacity, that is, prevent a critical decrease in ground clearance, breakdowns, increased loads on the body and frame.
The manufacturer's choice of a specific suspension design depends not only on automotive industry trends, but also on the specific purpose of the car model, its dimensions, weight, and drive type. Of considerable importance are experience, technical developments and established traditions in the layout of machines. All this led to the emergence of a fairly large number of varieties of car suspensions.
ESSENTIAL ELEMENTS
As you know, the suspension is called all the parts and assemblies that connect the body or frame with the wheels. Suspension components can be divided into three main groups:
elastic elements. Spring, spring, torsion bar, airbag. They are responsible for the vertical forces that occur when driving over bumps.
Guide elements. Lever, rod, rod, beam. The nature of the movement of the wheels is determined, the moments of longitudinal and lateral forces are transmitted.
damping elements. Shock absorbers that dampen vibrations.
At the same time, the suspension contains several elements that can be attributed to several groups. For example, an anti-roll bar that connects the roles of both a guide and an elastic element, or a semi-dependent suspension beam, with similar functions.
DEPENDENT AND INDEPENDENT
Although these terms are familiar to most motorists, not everyone understands their meaning. Meanwhile, “independence” is understood not as the autonomy of the suspension as a unit (this simply cannot be), but the free movement of each of the wheels relative to the other on the same axle. Exists:
1. Independent suspension, where the wheel moves independently during compression or rebound, without affecting the others;
2. Dependent suspension, where both wheels in a pair are connected by a rigid structural element, more often by a continuous beam of the drive axle;
3. Semi-independent suspension, where the wheels, although connected by longitudinal elements, their vertical movement is relatively free.
MAIN TYPES OF MODERN PENDANTS
McPherson. It consists of a lower transverse arm, a stabilizer and a rotating shock absorber strut attached to the body through a thrust bearing. The shock absorber is often (but not necessarily) located inside the coil spring. Despite the fact that the invention is more than 50 years old, MacPherson is still the most commonly used type of independent suspension for the front axle of a car, regardless of the drive. The reason is the simplicity of design and ease of maintenance.
Double wishbone suspension - the "ancestor" of MacPherson, the second most popular independent front suspension. The design of two trailing arms of different lengths is more complex and more demanding on the size and quality of the hinges, but it provides more opportunities for adjusting the wheel alignment angles (camber), which has a positive effect on handling.
Multi-link suspension, a further development of the double wishbone, is the most difficult, but effective way to ensure maximum wheel traction. The multi-link consists of at least three side arms and one longitudinal or vertical element. The goal is to limit the movement of the axle to six degrees of freedom, while ensuring maximum comfort of movement. The most popular, although expensive, independent suspension for the rear axle of a passenger car.
Torsion beam, the main type of rear suspension for small or budget front-wheel drive cars. Two trailing arms and a cross beam are connected into one H-shaped elastic element. Sometimes, for additional elasticity, a metal rod is placed inside the beam. The design has a very low torsional rigidity, but a large bending stiffness, which ensures independent wheel travel in a vertical plane.
THE PAST AND FUTURE OF PENDANTS
Cases where the automotive industry permanently abandons the inventions of the past are infrequent. A vivid example of this is the De Dion pendant, named, like MacPherson, in honor of its inventor, and invented in the 19th century for steam engines. This suspension (which can be both dependent and semi-dependent) was designed to reduce unsprung mass - the wheels were connected by a system of transverse pipes, and the axle gearbox (often the rear) was attached to the car chassis, lightening the weight of the suspension. For a long time, "De Dion" was not used by manufacturers, but relatively recently, smart cars were equipped with this type of suspension - as the only one capable of coping with the task.
Spring suspension, also developed before the advent of the car, although it has practically disappeared from the design of modern passenger cars, is currently actively used in commercial vehicles, where reliability and simplicity of design are important - after all, it consists only of springs on which a continuous axle is attached, and shock absorbers.
Front leaf spring suspension - Drawings, 3D Models, Projects, Trucks
The trailing arm suspension, which was previously actively used on rear and all-wheel drive vehicles, mainly with a continuous axle beam, is now also little used. The reason is its complexity (the suspension consists of 4 trailing arms and an oblique jet thrust) does not correspond to handling, while using quite a lot of the car's interior space.
Trailing arm suspension - Encyclopedia of the magazine "Behind the wheel"
Suspension on diagonal levers, front dependent suspension with a continuous beam axle and other similar ones are also used less and less, most often for specific purposes, for example, on off-road vehicles or tractors, as a “candle” suspension popular at the dawn of the automotive industry.
Axle with diagonal levers | AL-KO
The approach to elastic elements has recently also become different. In addition to springs, which were used not only in purely spring, but also in other types of suspension, automakers practically abandoned torsion bars - longitudinal metal rods.
Air suspension is becoming more and more widely used, other innovative technologies are being used: such as adaptive suspension or a fundamentally innovative electromagnetic suspension, which is a set of devices in the form of a rack for each wheel, replacing the spring and shock absorber and controlled by an electronic unit. One of our future materials will be devoted to these technologies.
WHICH SUSPENSION IS BETTER
In the meantime, let's return to the good old "iron" pendants, compare them in terms of maintainability. It should be noted that problems with the chassis most often depend not on the type of suspension, but on a number of reasons: the operating mode, the quality of the components, and, last but not least, the appropriateness of the application. A vivid example is the suspension of rear-wheel drive VAZ cars, where the front two-lever, which works great on other cars, is prone to breaking ball joints due to their overload, and the rear trailing arms do not provide the necessary directional stability.
However, if we take this kind of miscalculation, different types of pendants have their pros and cons. Easy to service
anii and good road holding MacPherson is quite hard and short-stroke. A semi-independent beam, with all its reliability, does not provide comfort (including acoustic), therefore it is used mostly on cars not higher than class C. A multi-link suspension, with all its positive qualities, is difficult and expensive to maintain.
CARE AND MAINTENANCE
In any case, no matter what suspension the car has, its owner should not forget about timely diagnostics and repairs. Increased rolls, a knock in the suspension, yaw from side to side, pecks during acceleration and braking - all at least a reason to consult with car service specialists.
At every opportunity, check the condition of rubber products: anthers, stabilizer bushings, silent blocks. At the service station, they will help to assess the play of ball joints, tie rod ends, levers - it is quite difficult to do this on your own. A fault diagnosed in time will save you from additional expenses and positively affect the safety of the car.
