Suspension- a set of devices that provide an elastic connection between the sprung and unsprung masses Suspension reduces the dynamic loads acting on the sprung mass. It consists of three devices:
- elastic
- guiding
- damping
elastic device 5, vertical forces acting from the road are transferred to the sprung mass, dynamic loads are reduced and ride smoothness is improved.
Rice. Rear suspension on oblique levers of BMW cars:
1 - cardan shaft of the drive axle; 2 - support bracket; 3 - axle shaft; 4 - stabilizer; 5 - elastic element; 6 - shock absorber; 7 - suspension guide lever; 8 - bracket support
Guide device 7 - a mechanism that perceives the longitudinal and lateral forces acting on the wheel and their moments. The kinematics of the guide device determines the nature of the movement of the wheel relative to the carrier system.
damping device() 6 is designed to dampen vibrations of the body and wheels by converting vibration energy into heat and dissipating it into the environment.
The design of the suspension must provide the required smoothness of movement, have kinematic characteristics that meet the requirements of vehicle stability and controllability.
dependent suspension
Dependent suspension is characterized by the dependence of the movement of one wheel of the axle on the movement of the other wheel.
Rice. Scheme of dependent wheel suspension
The transfer of forces and moments from the wheels to the body with such a suspension can be carried out directly by metal elastic elements - springs, springs or with the help of rods - a rod suspension.
Metal elastic elements have a linear elastic characteristic and are made of special steels with high strength at large deformations. Such elastic elements include leaf springs, torsion bars and springs.
Leaf springs are practically not used on modern passenger cars, with the exception of some models of multi-purpose vehicles. It can be noted the models of passenger cars that were previously produced with leaf springs in the suspension, which continue to be used at the present time. Longitudinal leaf springs were installed mainly in the dependent wheel suspension and served as an elastic and guiding device.
On cars and trucks or minibuses, springs are used without springs, on trucks - with springs.
Rice. Springs:
a) - without a sprung; b) - with a sprung
Springs as elastic elements are used in the suspension of many cars. In the front and rear suspensions manufactured by various companies in most passenger cars, helical coil springs with a constant bar section and winding pitch are used. Such a spring has a linear elastic characteristic, and the necessary characteristics are provided by additional elastic elements made of polyurethane elastomer and rubber rebound buffers.
On Russian-made passenger cars, the suspensions use cylindrical helical springs with a constant bar section and pitch, in combination with rubber impact buffers. On cars from manufacturers in other countries, for example, the BMW 3 Series, a barrel-shaped (shaped) spring with a progressive characteristic is installed in the rear suspension, achieved due to the shape of the spring and the use of a variable section bar.
Rice. Spiral springs:
a) a cylindrical spring; b) barrel spring
On a number of vehicles, a combination of coil and shaped springs with variable bar thickness is used to provide progressive performance. The shaped springs have a progressive elastic characteristic and are called "mini-blocks" for their small height. Such shaped springs are used, for example, in the rear suspension of Volkswagen, Audi, Opel, etc. Shaped springs have different diameters in the middle part of the spring and along the edges, and miniblock springs also have a different winding pitch.
Torsion bars, as a rule, of round section are used on cars as an elastic element and a stabilizer.
The elastic torque is transmitted by the torsion bar through splined or square heads located at its ends. Torsion bars on a car can be installed in the longitudinal or transverse direction. The disadvantages of torsion bars include their large length necessary to create the required stiffness and suspension travel, as well as the high alignment of the splines at the ends of the torsion bar. However, it should be noted that torsion bars have a small mass and good compactness, which allows them to be successfully used on passenger cars of medium and high classes.
Independent suspension
Independent suspension ensures that the movement of one wheel of the axle is independent of the movement of the other wheel. According to the type of guiding device, independent suspensions are divided into lever and MacPherson suspensions.
Rice. Scheme of independent linkage wheel suspension
Rice. MacPherson independent suspension scheme
Link suspension- suspension, the guiding device of which is a lever mechanism. Depending on the number of levers, there can be double-lever and single-lever suspensions, and depending on the swing plane of the levers - cross-lever, diagonal-lever and longitudinal-lever.
List of types of car suspensions
This article discusses only the main types of car suspensions, while there are actually many more types and subspecies of them, and besides, engineers are constantly developing new models and refining old ones. For convenience, here is a list of the most common. In the following, each of the suspensions will be considered in more detail.
- Dependent suspensions
- On a transverse spring
- On longitudinal springs
- With guide levers
- With support pipe or drawbar
- "De Dion"
- Torsion-lever (with connected or mated levers)
- Independent suspensions
- With swing axles
- On trailing arms
- spring
- Torsion
- hydropneumatic
- Pendant "Dubonnet"
- On double trailing arms
- On slanting levers
- On double wishbones
- spring
- Torsion
- Spring
- On rubber elastic elements
- Hydropneumatic and pneumatic
- Multi-link suspensions
- candle pendant
- Pendant "MacPherson" (swinging candle)
- On longitudinal and transverse levers
- Active suspensions
- Pneumatic suspensions
Suspension - how much in this sound ... In every sense. What is it, but she knows how to sound. Depending on the design, the suspension can be simple, or it can have the most complex design. In the same way, it can be reliable, and vice versa, “crumble” after every thousand kilometers.
During its existence, the car suspension has gone through a huge evolutionary path. Once upon a time, the spring system was considered the height of progress, and today the design of modern suspensions can be compared to a work of art - they are so perfect, complex and expensive devices.
Purpose and vehicle suspension device
So, what is the purpose of a car suspension? She, like her distant predecessors, installed in horse-drawn carriages, is designed to make movement more comfortable and safe. Resilient suspension elements dampen the shocks, jolts and vibrations that accompany any ride on any road.
However, suspension tasks are not limited to comfort alone. Its second function is to assist in maneuvers. The complexity of the suspension design is often due to this very reason: engineers are still trying to add stability, controllability, and safety to the car.
And finally, the modern suspension helps to slow down a lot, absorbing forward momentum. By the quality of braking, you can sometimes determine how the suspension is configured and how functional.
What is included in the suspension device? Simply put, everything that is between the wheels and the power frame of the car. These are well-known shock absorbers (where without them), springs, levers, traction, stabilizers, ball bearings, silent blocks and other elements. Conventionally, they can be divided into the following categories:
- All types of springs, springs and torsion bars are elastic suspension elements. Their task is to take on and bounce off shocks from driving over bumps.
- All types of shock absorbers (conventional oil and gas-oil, pneumatic, magnetic) are suspension damping elements. They must absorb shocks and shaking, not letting them go further on the car body.
- Levers, steering knuckles, transverse rods with these are guide elements. Their task is to form the correct position of the wheel when turning and driving in a straight line. Steering gear is enough to turn the wheels, but in order for the wheel to take the correct position during maneuvers, suspension elements are needed.
- Silent blocks, ball bearings and other small rubber-metal parts are needed not only to fasten all suspension elements together, but also to partially mitigate vibration and shock.
- The anti-roll bar, as the name implies, is designed to align the body in turns so that the car does not fall sideways during sharp maneuvers.
The principle of operation of car suspensions
Whether it is the suspension of KamAZ, Mercedes or an old Oka, the principle of its operation does not change. And it is unlikely to change in the near future, despite the abundance of new engineering ideas.
The basic principle of operation of any suspension is as follows: the impact energy (this is a wheel that has fallen into pits or hit a stone) is converted into the energy of movement of individual parts of the suspension. How does it manifest itself?
- The wheel hit a rock. It rose above the plane on which it was rolling, and with it the levers, the steering knuckle, and the traction changed their position.
- Further, the shock absorber is included in the matter: it is compressed, using for this the kinetic energy of the push of the wheel from the bottom up. At the same time, the spring is also compressed, which until then was in a relatively calm position.
- The elastic compression of the shock absorber and spring, the movement of the rod, the partial absorption of the impact by rubber-metal bushings - all this dampens the impact and prevents it from passing further onto the power frame of the machine.
- And then there should be a “recoil”, and again the springs play its role. As the spring expands, it returns the damper to its original position - this is the last step that the suspension takes when it encounters difficulties.
Of course, there are alternative types of construction, but if you look, their principle of operation is exactly the same.
Pendant classification
Improving the design of the automobile suspension, the engineers indulged in all serious. Here you have a multi-link, and an ordinary dependent beam, and a Bose jumping suspension ... And they all found their fans and haters. The classification of suspensions is already quite complex, since different design features and solutions can be combined in one car.
What, you haven't seen the jumping suspension yet?
dependent
Dependent suspension work The oldest design that came to the automotive industry from the era of horse-drawn carriages. Its main element is a rigid inextricable axle that connects two wheels, as a result of which they cannot move relative to each other. That is, if one wheel hits a stone, the second will deviate to the side along with it. The easiest option to understand is the wheels in children's cars, this is how they are mounted on one axle.
True, our cars have gone far ahead of toy cars, so the beam (axle) connecting the two wheels is equipped with shock absorbers, springs, and transverse rods. However, of all the varieties, this is the simplest, most indestructible and cheap suspension, in which malfunctions rarely occur.
Independent
Operation of the independent suspension The creation of a gloomy German genius. Independent - because each wheel moves independently of the second in a pair. That is, if one wheel hits a stone, it will rise along with the levers and springs on its side, while the second one does not react to this and does not change its position. Independent suspension is very comfortable for passengers, but it can have many separate elements, each of which fails sooner or later.
semi-independent
Semi-independent suspension work This is a special type of suspension with a torsion beam. A U-shaped torsion (twisting) beam is installed as a common axis for two wheels. The layout of its design gives the wheels a small degree of freedom, since the preloaded beam “plays” slightly, partially damping the rolls in corners.
Pneumatic
Air suspension operation She migrated to cars from heavy transport. Instead of metal springs, it uses compressed air cylinders that are inflated to a certain pressure. The pressure in the cylinders can be different, as a result, the characteristics of the suspension also change. They put it on luxury cars as an additional option.
Torsion
Torsion suspension work This type of suspension in passenger cars is rare. More suitable for large vehicles. A characteristic feature in this suspension is the use of longitudinal torsion bars, which works on twisting, trying to level the car when it hits bumps.
Spring
Spring suspension work Such a suspension is rarely used in passenger cars, except perhaps on some SUVs. But it is very common on trucks and buses. A feature of the suspension is the use of springs as a damping component to absorb shocks.
hydraulic
Hydraulic suspension of the car - general view It differs in the design of shock absorbers, on which an additional reservoir with hydraulic fluid is installed. If in other suspension options, shock absorbers are just a boring utilitarian element, in a hydraulic suspension, new prospects open up for them. First of all, it is the ability to control the height of the clearance and the stiffness of the suspension response. It can also adapt to driving style and road conditions.
McPherson
MacPherson suspension device The same independent suspension, extremely successful - with a MacPherson strut (aka MacPherson, aka a swinging candle), thanks to which we managed to get rid of one of the levers. MacPherson strut is attached to the wheel hub and body of the car, so it successfully replaces one of the suspension arms. In most cases, this is how the front suspension is done.
The peculiarity of the rack is not only at the attachment points. It combines a shock absorber and a spring in one design, which seriously saves space. In addition, many manufacturers produce a rack, which consists of a separate cushioning block and a “glass” holder, which seriously reduces the cost of maintenance.
Multi-link
Operation of the electromagnetic shock absorber The most progressive type of suspension to date. Instead of liquid or air, it uses transducers with powerful magnets. On command from the control unit, electricity is supplied to the magnets, due to which the electromagnetic shock absorbers change the stiffness, vehicle clearance, and handling. If you have ever seen dancing or jumping cars, they will definitely have an electromagnetic suspension.
Conclusion
This is just a brief description of the main types of car suspensions. If you understand more deeply, there are other, rather unusual design solutions. Yes, and the conclusions can be drawn ambiguous, because each automaker brings some of its "chips" to the suspension design. But consumers are provided with any type of pendants to choose from: soft, sports, standard and exclusive. And that's great.
With the continuous development of technology, modern cars are becoming more complex every year. This statement applies to all systems and mechanisms without exception, including the vehicle suspension. The suspension brackets of cars produced today are quite a complex device that combines hundreds of parts.
The elements of many car suspensions are controlled by a computer (electronic method), which captures all sensor readings and, if necessary, is able to instantly change the characteristics of the car. The evolution of the suspension, to a large extent, has contributed to the fact that you and I can drive more comfortable and safer cars, however, the main tasks that the automobile suspension has performed and continue to perform have remained unchanged since the days of carriages and horse-drawn carriages. Let's find out exactly what the merit of these mechanisms is, and what role the rear suspension plays in the life of the vehicle.
1. Purpose of the rear suspension
An automobile suspension is a device that provides elastic adhesion of the wheels of a car to the supporting structure of the body. In addition, the suspension regulates the position of the vehicle body during movement and helps to reduce the load on the wheels. In the modern automotive world, there is a large selection of different types of automotive suspensions, the most popular of which are spring, pneumatic, spring and
This element takes part in all processes that occur between the road surface and the car. Therefore, all design changes and improvements in the suspension device were aimed at improving certain performance qualities, which primarily include:
Comfortable conditions of movement. Imagine that you are driving to a neighboring town in a carriage with wooden wheels, how does it feel? It is clear that it is much more pleasant to overcome several hundred kilometers in a modern car, even despite the quality of the current roads, which in some places seem to have not changed since the time of those same horse-drawn carriages. It was thanks to the functioning of the suspension that it became possible to achieve optimal smoothness of movement, eliminating unnecessary body vibrations and shocks from road irregularities.
The level of controllability of the car, characterized by the correct reaction of the wheels to the "commands" of the steering wheel. But the ability to change direction (turn) also appeared thanks to the suspension (to be more specific, the front one). Of particular relevance, accuracy and ease of maneuvering, acquired with the beginning of the growth of speeds: the higher the speed becomes, the more the behavior of the vehicle changes when the steering wheel is turned.
Safety of vehicle passengers. The design includes some of the most actively moving parts of the machine, which means that the safety of movement directly depends on its characteristics.
Basically, the suspension of front-wheel drive cars is semi-independent and is located on the rear wheels, located on an elastic "P" shaped beam. That is, it consists of two trailing arms, one of the ends of which is fixed to the body, and the wheels are placed on the second. The trailing arms are interconnected by a transverse beam, which gives the suspension the appearance of the letter "P". This type of rear suspension has the most optimal wheel kinematics, while being compact and simple, however, its design does not allow the transmission of torque to the rear wheels, so a semi-independent rear suspension is used on most front-wheel drive vehicles.
It has the following advantages:
- simple design;
High level of rigidity in the transverse direction;
small mass;
Possibility of changing characteristics due to changes in the cross section of the beam.
However, like any system, a semi-independent suspension also has some disadvantages, expressed in a non-optimal change in the camber and special requirements for the geometric parameters of the bottom of the body at the attachment points.
As a rule, the rear suspension device is always simpler than the front one. On the bulk of cars, the rear wheels are not able to change the angle of rotation, which means that the constructive side of the rear suspension should provide only vertical movement of the wheel.
However, the condition of the rear suspension directly affects the safety of the vehicle and the comfort of driving it. Therefore, it is worth remembering that it depends on regular rear suspension diagnostics and timely repair of its parts whether you can avoid more serious problems in the future. Sometimes, this even applies to the safety of the lives of the driver and passengers.
In addition to semi-independent suspension, low-cost car models often use dependent rear suspension. In this version, the wheels are interconnected by means of a rear axle beam, which, in turn, is attached to the car body by trailing arms. If the rear of a car with this type of suspension is subjected to an increased load, then slight disturbances in ride and slight vibrations may appear. This is considered the main disadvantage of dependent rear suspension.
2. Types of rear suspension and how they work
The rear suspension of cars has a fairly wide range of variations, but now we will consider only the most common and well-known types of it. Pendant "De Dion". This type of rear suspension was invented over a century ago, however, it is successfully used in our time. In those cases where, due to financial issues or layout considerations, engineers have to abandon independent suspensions, the old De Dion system comes in handy. Its design is as follows: the main gear housing is attached to the cross beam of the frame or to the body, and the wheel drive is carried out using semi-axes placed on hinges. The wheels are connected to each other by means of a beam.
Technically, the suspension is considered dependent, but thanks to the massive final drive mounting (attached separately from the axle), the unsprung mass is significantly reduced. Over time, the continuous desire of engineers to rid the rear axle of excess load has led to an improvement in the design, and in our time we can observe both its dependent and independent variants. So, for example, in a Mercedes R-class car, engineers were able to successfully combine the advantages of various schemes: the final drive housing turned out to be fixed on a subframe; wheels - suspended on five levers and driven by swinging axle shafts; and the role of elastic elements, in such a design, is performed by pneumatic racks.
Dependent suspension is the same age as the entire automotive industry, which, together with it, has gone through various stages of improvement and has successfully reached our days. However, in the world of rapid development of modern technologies, every year it becomes more and more just a part of history. The fact is that bridges that rigidly connect the wheels are used today only on classic SUVs, which include cars such as UAZ, Jeep or Nissan Patrol. Even less often, they can be found on domestic-made passenger cars developed more than half a century ago (Volga or Zhiguli).
The main disadvantage of using this type of suspension is obvious: based on the design, the movement of one wheel is transmitted to the other, resulting in resonant oscillations of the wheels in the transverse plane (the so-called "Shimmy" effect), which not only harms comfort, but also significantly affects the vehicle's handling.
Hydropneumatic suspension. The rear version of such a device is similar to the front one and indicates the type of automobile suspension, which uses hydropneumatic elastic elements. The ancestor of such a system was the Citroen company, which first applied it on its cars back in 1954. The result of its further developments are Hydractive active suspensions, which are used by the French company to this day. The first generation (Hydractive 1) appeared in 1989. The principle of operation and design of such devices is as follows: when hydropneumatic cylinders pump liquid into elastic elements (spheres), the hydroelectronic unit controls its quantity and pressure.
Between the cylinders and the elastic elements there is a shock-absorbing valve, through which, in the event of body vibrations, a liquid passes, contributing to their attenuation. In soft mode, all hydropneumatic elastic elements are combined with each other, and the gas volume is at the maximum level. The pressure in the spheres is maintained within the required parameters and the rolls of the car (its deviations from the vertical position when driving, most often caused by road irregularities) are compensated.
When it becomes necessary to activate the hard suspension mode, the voltage is applied automatically by the control system, after which the front suspension struts, cylinders and additional elastic elements (located on the stiffness regulators), in relation to each other, are in an isolated position. When the vehicle turns, the stiffness of a single sphere can change, while when driving in a straight line, the changes apply to the entire system.
Multi-link suspension. The first mass-produced car with multi-link suspension saw the world in 1961 and it was the Jaguar E-type. Over time, it was decided to consolidate the success obtained by using this type on the front axle of the car (for example, certain Audi models). The use of a multi-link suspension provides the car with incredible smoothness of movement, excellent handling, and at the same time helps to reduce noise.
Starting in the 1980s, Mercedes Benz engineers, instead of a pair of double ones, began to use five separate levers on their cars: two of them hold the wheel, and the remaining three provide it with the necessary position in the vertical and horizontal planes. Compared to a simpler double wishbone suspension, the multi-link version is just a godsend for the most successful layout of components and assemblies. Moreover, having the ability to change the size and shape of the levers, you can much more accurately set the necessary characteristics of the suspension, and thanks to the elasto-kinematics (the laws of the kinematics of any suspension that incorporates elastic elements), the rear suspension also has a steering effect when cornering.
As a rule, evaluating the suspension of a vehicle, most motorists, first of all, turn their attention to such properties as the level of controllability, comfort, and stability (depending on the priorities, the sequence may be different). Therefore, they absolutely do not care what type of suspension is installed on their car and what design it has, the main thing is that it simply meets all the necessary requirements.
In principle, it is correct, because the choice of the type of suspension, the calculation of its geometric parameters and the technical capabilities of individual components is the task of engineers. During the development and design, the vehicle goes through a lot of various calculations, tests and trials, which means that the suspension of a standard car already has optimal consumer characteristics that meet the requirements of most customers.
3. Torsion type stabilizer
Modern passenger cars can be equipped with one of two main types of stabilizers - lever or torsion bar. Lever Stabilizers(often called "jet rods") have the form of a hollow pipe, at the ends of which there are fasteners with silent blocks (they are rubber-metal hinges). They are installed between the fist mounts on one side and the seat on the body on the other. Due to the rigid fixation and springs, the installation of the stabilizer allows you to create a kind of triangle, the sides of which are a shock absorber (spring), a bridge (beam) and, accordingly, the stabilizer itself.
The torsion stabilizer is the main part of the car suspension, connecting the wheels with the help of a torsion element. Today, many car owners consider the torsion stabilizer to be an almost indispensable element of various types of car suspensions. Its fastening can be performed both on the front and rear axles of vehicles, however, on vehicles where the beam acts as a rear suspension, the stabilizer is not used, and the suspension itself performs its functions.
On the technical side of the issue, the stabilizer is a rod with a circular cross section, shaped like the letter "P". Usually, it is made of well-machined spring steel and is placed under the body in a horizontal direction (across). To the body, the part is attached in two places, and rubber bushings are used to fix it, which contribute to its rotation.
As a rule, the shape of the torsion stabilizer takes into account the placement of all automotive components located under the bottom of the body . When the distance between the bottom of the body and the lower part of the suspension changes on one side of the car, the placement of the stabilizer mounts shifts slightly, which causes the torsion bar to bend. The greater the height difference, the stronger the resistance of the torsion bar, due to which the stabilizing effect is more smooth (compared to a lever stabilizer). Therefore, most often, it is installed on the front suspension.
Any car consists of a number of components, each of which performs its own functions. The engine converts energy into mechanical motion, the transmission allows you to change the traction and torque, as well as transfer it further, the chassis ensures the movement of the car. The last component consists of several components, including the suspension.
Purpose, main components
The suspension in the car performs a number of important functions:
- Provides elastic fastening of the wheels to the body (which allows them to move relative to the bearing part);
- It dampens the vibrations received by the wheels from the road (thus, the smoothness of the car is achieved);
- Provides constant contact of the wheel with the roadway (affects handling and stability);
Since the advent of the first car and to our time, several types of this component of the chassis have been developed. But at the same time, it was not possible to create an ideal solution that would suit all parameters and indicators. Therefore, it is impossible to single out any one of all existing types of car suspensions. After all, each of them has its own positive and negative sides, which predetermine their use.
In general, any suspension includes three main components, each of which performs its own functions:
- elastic elements.
- Damping.
- Guiding systems.
The task of the elastic elements is the perception of all shock loads and their smooth transfer to the body. Additionally, they ensure constant contact of the wheel with the road. These elements include springs, torsion bars, springs. Due to the fact that the last type - springs, is practically not used now, we will not further consider the suspension in which they were used.
Twisted springs are the most widely used as elastic elements. On trucks, another type is often used - air bags.
Coiled suspension springs
Damping elements are used in the design to dampen vibrations of elastic elements by absorbing and dissipating them, which prevents body swaying during suspension operation. This task is performed by shock absorbers.
Front and rear shock absorbers
Guide systems connect the wheel with the bearing part, provide the ability to move along the required trajectory, while keeping it in a given position relative to the body. These elements include all kinds of levers, rods, beams, and all other components involved in the creation of movable joints (silent blocks, ball bearings, bushings, etc.).
Kinds
Although all of the listed components are typical for all existing types of vehicle suspensions, the design of this chassis component is different. Moreover, the difference in the device affects the operational, technical parameters and characteristics.
In general, all types of car suspensions currently in use are divided into two categories - dependent and independent. There is also an intermediate option - semi-dependent.
dependent suspension
Dependent suspension began to be used on cars from the moment they appeared and it “migrated” to cars from horse-drawn carts. And although this type has improved significantly during its existence, the essence of the work has remained unchanged.
The peculiarity of this sum lies in the fact that the wheels are interconnected by an axle, and do not have the ability to move separately relative to each other. As a result, the movement of one wheel (for example, when falling into a pit) is accompanied by a displacement of the second.
In rear-wheel drive vehicles, the connecting axle is the rear axle, which is also an element of the transmission (its design includes the main gear with differential and half shafts). In front-wheel drive cars, a special beam is used.
2009 Dodge Ram dependent suspension
Initially, springs were used as elastic elements, but now they have been completely replaced by springs. The damping element in this type of suspension is shock absorbers, which can be installed separately from the elastic elements or coaxially with them (the shock absorber is installed inside the spring)
In the upper part, the shock absorber is attached to the body, and in the lower part - to the bridge or beam, that is, in addition to damping oscillatory movements, it also acts as a fastener.
As for the guide system, in the dependent suspension design, it consists of trailing arms and a transverse link.
4 trailing arms (2 upper and 2 lower) provide a completely predictable movement of the axle with wheels in all existing directions. In some cases, the number of these levers is reduced to two (the upper ones are not used). The task of the transverse thrust (the so-called Panhard thrust) is to reduce body roll and hold the trajectory.
The main advantages of the dependent suspension of this design are the simplicity of the design, which affects the reliability. It also provides excellent traction with the roadway of the wheels, but only when driving on a flat surface.
The big disadvantage of this type is the possibility of losing grip when cornering. At the same time, due to the alignment of the axle with the transmission elements, the rear axle has a massive and overall structure, for which it is necessary to provide a lot of space. Due to these features, the use of such a suspension for the front axle is almost impossible, so it is used only at the rear.
The use of this type of suspension on passenger cars has now been minimized, although it is still found on trucks and full-size frame SUVs.
Independent suspension
Independent suspension is different in that the wheels of one axle are not connected to each other and the movement of one of them does not have any effect on the other. In fact, in this type, each wheel has its own set of component parts - elastic, damping, guide. Between themselves, these two sets practically do not interact.
MacPherson struts
Several types of independent suspension have been developed. One of the most popular types is the MacPherson strut (aka “swinging candle”).
The peculiarity of this type lies in the use of the so-called suspension strut, which performs three functions simultaneously. The strut includes both a shock absorber and a spring. In the lower part, this component of the suspension is attached to the wheel hub, and in the upper part, by means of supports, to the body, therefore, in addition to accepting and damping vibrations, it also provides wheel mounting.
MacPherson gas oil strut device
Also in the design there are one more components of the guiding system - transverse levers, the task of which, in addition to ensuring the movable connection of the wheel with the body, is also to prevent its longitudinal movement.
To combat body roll while driving, another element is used in the suspension design - an anti-roll bar, which is the only link between the suspensions of two wheels of the same axle. In fact, this element is a torsion bar and the principle of its operation is based on the occurrence of an opposing force during twisting.
MacPherson strut suspension is one of the most common and can be used on both front and rear axles.
It is characterized by relatively compact dimensions, simple design and reliability, for which it has gained popularity. Its disadvantage is the change in the camber angle with a significant wheel travel relative to the body.
lever type
Lever independent suspensions are also a fairly common option used on cars. This type is divided into two types - double-lever and multi-link suspension.
The design of the double-lever suspension is made in such a way that the suspension strut performs only its direct tasks - it dampens vibrations. The wheel mount lies entirely on the control system, consisting of two transverse levers (upper and lower).
The levers used are A-shaped, which provides a reliable hold on the wheel from longitudinal movement. In addition, they are of different lengths (the upper one is shorter), so that even with significant movements of the wheel relative to the body, the camber angle does not change.
Unlike the MacPherson strut, the double wishbone suspension is larger and more metal-intensive, although a slightly larger number of components does not affect reliability, but it is somewhat more difficult to maintain.
The multi-link type, in fact, is a modified double-lever suspension. Instead of two A-shaped in its design, up to 10 transverse and trailing arms are used.
Multi-link suspension
Such a constructive solution has a positive effect on the smoothness of the ride and handling of the car, the safety of the wheel position angles during suspension operation, but at the same time it is more expensive and difficult to maintain. Because of this, in terms of applicability, it is inferior to MacPherson struts and a two-lever type. It can be found on more expensive cars.
Semi-independent suspension
A kind of middle ground between dependent and independent suspension is semi-dependent.
Outwardly, this view is very similar to a dependent suspension - there is a beam (which does not include transmission elements) made integral with the trailing arms to which the wheel hubs are attached. That is, there is an axle connecting the two wheels. The beam is also attached to the body using the same levers. Springs and shock absorbers act as elastic and damping elements.
Semi-independent suspension with Watt mechanism
But unlike a dependent suspension, the beam is torsion bar and can work in twisting. This allows the wheels to move independently of each other in a vertical direction within a certain range.
Due to the simplicity of design and high reliability, the torsion beam is often used on the rear axles of front-wheel drive vehicles.
Other types
The main types of suspensions used on cars are discussed above. But there are several more types, although the rest are not used now. Such, for example, is the DeDion pendant.
In general, DeDion differed not only in the design of the suspension, but in the transmission of rear-wheel drive vehicles. The essence of the development was that the main gear was removed from the design of the rear axle (it was rigidly attached to the body, and the rotation was transmitted by half shafts with CV joints). The rear axle itself could have both independent and dependent suspension. But due to a number of negative qualities, this type of car has not received wide distribution.
De Dion pendant
It is also worth mentioning the active (it is also adaptive) suspension. It is not a separate type, but is, in fact, an independent suspension, and differs from those described above in some design nuances.
This suspension uses shock absorbers (hydraulic, pneumatic or combined) with electronic control, which allows you to somehow change the operation parameters of this unit - increase and decrease stiffness, increase ground clearance.
But due to the complexity of the design, it is very rare and only on premium segment cars.
Every driver should know and understand what a suspension is and what functions it performs. And it doesn't matter if you have been driving a car for 10 years or just about to get a license. However, many have gaps in this matter, and do not even know what exactly the car suspension affects. But the comfort and convenience that we feel when driving our own car directly depends on it. But, at the same time, when driving over rough terrain, it is the suspension that can cause discomfort. So what is this node responsible for? What parts does it consist of?
It is to all these questions that you can get detailed answers in the article below. However, we will pay attention not only to the structural and functional features that a car suspension has, but also get acquainted with its most common types.
1. Car suspension: all the most important about the design features and functions performed
First of all, it is worth understanding the question, what is a car suspension? At its core, it is a knot or a structure of a specific number of parts that are fastened together in a certain way. What is the suspension for? Thanks to a certain design, it connects the machines with its wheels, thus providing the possibility of movement. Depending on the elements and parts that make up the suspension, as well as the features of their installation, the connection between the body and the wheels can be either rigid or elastic.
Generally Suspension is an element of the chassis of the car and plays a very important role in its functioning. Consider the most common list of parts that make up the integral suspension design of modern cars:
1. Guide elements. It is thanks to them that the wheels are connected to the body and transmit the force of movement to it. Also, thanks to them, the nature of the movement of the wheels relative to the body of the car is determined. Under the guide elements it is necessary to understand all kinds of levers for fastening and connecting parts. They can be longitudinal, transverse and double.
2. Elastic element. It is a kind of "adapter" between the wheels and the car body. It is he who perceives the load from the bumps in the road, accumulates it and transfers it to the body. Elastic elements can be made both from metal and from other affordable and durable materials. Metal - these are springs, springs (cast springs are used mainly on trucks) and torsion bars (in torsion suspension types). As for non-metallic elastic elements, they can be made of rubber (buffers and bumpers, but they are mainly used as an addition to metal devices), pneumatic (the properties of compressed air are used) and hydropneumatic (az and working fluid are used) elements.
3. Extinguishing device. In other words, this is car shock absorber. It is needed in order to reduce the amplitude of body vibrations, which are exactly what the work of the elastic element causes. The operation of this device is based on the hydraulic resistance that occurs during the flow of fluid through the calibration valves from one cylinder cavity to another. Although, in general, a shock absorber can consist of both two cylinders (double-tube) and one (single-tube).
4. Thanks to him, it is possible to counteract the rapidly growing roll that is formed during the implementation of the turn. It works by distributing weight across all wheels of the car. At its core, the stabilizer is an elastic rod, which is connected to the rest of the suspension elements through the racks. It can be installed both on the front and on the rear axle of the car.
5. Wheel support. It is located on the rear axle and takes the entire load from the wheel, distributing it to the levers and shock absorber. The same device is on the front axle, only it is called "swivel clack".
6. Fastening elements. Thanks to them, all elements and parts of the suspension are connected both to each other and attached to the car body. The main types of fasteners, which are most often used in the suspension, include: rigid connection with bolts; connection using elastic elements, which are rubber-metal bushings or silent blocks); ball joint.
In general, there are a fairly large number of types and types of pendants that can perform different functions and have different purposes and placement. Take for example the rear dependent suspension. Its design is simple and easy to understand for ordinary people: it is held on the car with the help of two sufficiently strong coil springs, and also has an additional mount on four levers that are in a longitudinal position. In general, this design has a rather small weight, so it has a rather strong effect on the smoothness of the car. But let's still not get ahead of ourselves so fast, and first consider a number of signs behind which car suspension is divided into the following several types:
- double-lever and multi-lever;
active;
Torsion;
Dependent and independent;
Front and back.
Let's go in order and take a closer look at the two- and multi-link suspensions of the car.
What features are hidden behind two- and multi-link automotive units?
In general, their name comes from the type of attachment, and to be more precise, from the design features of the levers with which these suspensions are attached to the car body. In the first case, they are attached to two transverse levers, one of which is the upper one (it is short), and the second is the lower one (it is longer). Also, specifically to reduce the sensitivity of the car and this unit to shocks that may occur when driving on an uneven surface, there is also an elastic element of a cylindrical shape between these fasteners.
However, such a double wishbone suspension design has a significant drawback, which is associated with extremely rapid tire wear. This happens because the lateral movements of the wheels are very small and this is reflected in the lateral stability of the wheel. But if we talk about the advantages of a double-lever suspension, then one cannot fail to mention the independence that each wheel of a car receives. This feature contributes to the stability of the car when driving over bumps, and also makes it possible to create high-quality and long-term adhesion of the wheels to the road surface.
Now let's try to understand in more detail what a multi-link car suspension scheme is, and how it differs from the one described above. All the main differences can be revealed by the following three points:
- Firstly, it is a more complicated version of the double wishbone suspension;
- Secondly- its design includes ball joints, due to which the softness of the car increases;
- third distinction- these are special silent blocks or swivel supports that are mounted on the frame. Thanks to these blocks, reliable sound insulation of the car body from the wheels in motion is ensured.
On such a suspension, you can also add longitudinal and transverse adjustments, which, by the way, can be installed separately on each independent element. But, despite all the advantages that the multi-link suspension provides and the possible ways to upgrade it, it has a serious cost. To give you an idea of the price, let's just say that this type of units are installed only on executive cars. The truth and value of such a suspension is obvious, since it allows you to control the movement of the car on the road as accurately as possible and ensures excellent contact of the wheel tires with the road surface.
2. We get acquainted with active and torsion types of automotive components: their main advantages and disadvantages
If you want to find out which types of car suspensions are the most modern and most often installed on supercars, you should definitely familiarize yourself with the active and torsion types of nodes. Let's start in order.
The special attention of car owners deserves Its name comes from the French word "torsion" and is translated into Russian as "twisting", which is the main visiting property of this type of automotive assembly. What is the secret and benefits? The most interesting thing about the design of such a suspension is the presence of a special elastic element, which is made of alloy steel. But what is so special about this steel, you ask?
The fact is that before being installed on a car, this steel undergoes a number of treatments, thanks to which it acquires the ability to twist around the longitudinal axis of the rod. At the same time, the elastic element itself can have the most diverse cross-sectional shape (square or round), consist of one continuous plate, or be assembled from several separate ones. The most important thing is that in its essence it is a prototype of a straightened spring, but with better characteristics and resistance to mechanical stress. How exactly the torsion bar suspension will be installed depends on the type of car. If this is an ordinary passenger car, then the installation is done longitudinally. If we are talking about trucks, then the torsion assembly will be mounted transversely. As you understand, this type of suspension is very convenient when operating a car. In particular, the following advantages should be highlighted:
- the elastic element is extremely light, especially when compared with conventional springs;
Compact design.
If you try to explain the meaning and role of elastic parts, then the following example should be given. If you suddenly need to go to a country road with a lot of deep potholes, having a torsion bar suspension on your car, you can lift the body without much effort. To do this, you will only need to pull the torsion bars with a special motor, which will allow you to adjust the required height of the road clearance.
But this is not all the advantages of such a suspension. If you need to change the wheel and at that moment you do not have a jack at hand, with the help of this device you can easily raise the body of the car on three wheels. Probably for this reason, the most widely used torsion bar type of automobile suspension is used on military armored vehicles.
Now let's pay a little attention to the active type of car suspension. When starting to get acquainted with its design, get ready right away: everything here is radically different from the classical design, there are no rods, no helical springs, or any other elastic elements that are mandatory for other types of suspensions. In order to mitigate and completely level out shocks and other unpleasant “consequences” of road surface irregularities, a special pneumatic or hydraulic strut, or a combination of both, is installed on such a suspension. Surprised? Let's try to understand in more detail.
At its core, this design is nothing more than a conventional cylinder, inside which is either a liquid or a compressed gas. The contents of the cylinder are distributed to the aforementioned racks due to the operation of the compressors. The convenience of this type of suspension is directly related to the fact that its use can be fully computerized. So, with the help of electronics, you can completely control the stiffness of the car's depreciation, and compensate for body distortions while driving on slopes and uneven roads.
Thus, we can sum up the following. The types of suspensions described in this section of the article give the driver a huge number of advantages that start in the comfort of movement and end in the ability to control the suspension directly from the car. However, they are not suitable for everyone. What is the reason for this is not only the old model of the car or its deterioration, but also the price inaccessibility.
3. Dependent and independent suspension - which is more rational to choose?
What's happened dependent suspension probably know those who bought their first car at the end of the last century or even before the collapse of the USSR. We think this gave a hint to everyone - today the dependent suspension is considered an outdated option and cannot be found on modern cars. The only thing is that it is installed on those makes and models of cars, the design of which has not changed for several decades. Of course, we can talk about cars that we have always considered the "children" of the domestic auto industry - the Volga and Zhiguli. Also, dependent suspension today can be found on UAZ vehicles, as well as on older and classic Jeep models.
Why is the suspension called "dependent"? Let's try to explain using a very simple example: when, being in such a car, you accidentally hit a bump with only one wheel, the angle of the entire suspension axis changes. It is not difficult to guess that there is very little comfort from such a ride. However, do not think that manufacturers have reached insanity, since they still install this kind of suspension. Their most important advantage is the simplicity of design, as well as its low cost, which allows you to drop the price from the cost of the entire vehicle.
There is another version of the dependent suspension of a car, which today can already be considered "ancient". We are talking about the de Dion dependent scheme, the first copies of which were installed on the very first cars. The peculiarity of such a suspension is that its final drive housing is attached to the car body, regardless of the bridge. Well, now let's move on to the most modern type of suspension, which is independent. In fact, it can be considered the complete opposite of the dependent suspension scheme, since in this embodiment we get the ability to move all four wheels absolutely independently of each other. That is, if one wheel hits a bump, this does not mean at all that all four wheels will bounce. By the way, we have already mentioned one of the options for such an independent suspension, and it is a two-lever system.
However, independent suspension can also be performed in other versions, among which it is necessary to draw your attention to the MacPherson strut, which is a very interesting example. For the first time they began to use it back in 1965, and the first car on which it was installed was the legendary Peugeot 204. How does such a suspension function and what elements does it consist of? In fact, there is nothing complicated here:
- one single lever;
A block that provides the suspension with anti-roll bars;
The second block, which consists of a telescopic shock absorber and a coil spring.
Of course, this option is far from a double wishbone suspension. The main disadvantages of the MacPherson circuit are that when driving in a car, a change in camber is felt quite strongly, especially if the car is driving on a high suspension. Also, road vibrations are practically not isolated.
We hope that our article has helped you to understand in more detail what types of suspensions exist and how they differ from each other. Such information will be useful to you not only in a situation where the car needs repairs, but also when purchasing a new “iron horse”. It remains only to recommend that you be more careful when driving a car and always listen to what it “tells” you. Happy travels!
