Suspension scheme multilink with A-shaped upper arm

Multi-link suspension, or Multilink, is the result of an improvement in the double wishbone independent suspension of a passenger car. Unlike standard version, the guide elements are not single V-shaped levers, but separate parts independent of each other. Their number usually varies from three to five elements. In the manufacture, the design features of the remaining suspension elements and their interaction are taken into account. Thanks to the Multilink scheme, the hub assembly gains additional attachment points and increased mobility, which significantly improves driving performance and overall vehicle handling.

History of appearance

The first car with Multilink suspension was the 1979 Porshe 928

For the first time, a multi-link suspension design was applied on sports coupe Porsche 928 in 1979. In 1982, the upgraded scheme was used on Mercedes models 190. The feature of the multi-link suspension design provided the car with excellent cornering. This was achieved by creating the effect of steering the loaded rear wheel a few degrees into the turn. Later, other automakers began to use multi-link suspension.

Elements of a multi-link suspension

Front suspension device

The Multilink front suspension consists of the following elements:

• Wishbones: provide vertical movements wheels and changing the angle of inclination of the hub assembly in the horizontal plane. Depending on the layout, the wishbones can also limit longitudinal movements.
• jet thrust: limit the movement of the hub in the longitudinal direction. They are mainly used on the rear multi-link suspension, in the front they are used to strengthen the structure.
• Springs: provide elastic connection of the suspension with the car body.
• Dampers: Designed to dampen vibrations.
• Stabilizer roll stability: Compensates for body roll when cornering.

Front multi-link Audi suspension Q5

The presence of ball bearings in the mounts of the levers and the hub allows you to turn the wheel. upper arms are often made adjustable in length, which provides extended options for setting the parameters of the wheel alignment angles.

Rear suspension device

Rear multi-link suspension Honda Accord

The multi-link suspension for the rear axle has a similar design, except for the possibility of turning the hub (with the exception of the thruster rear suspension). The most simple circuit includes two transverse and one longitudinal lower arm. Role top support performs suspension strut connected to the wheel hub. This design Multilink suspensions are characterized by relative simplicity and availability of production.

Among the various options for rear multi-link suspensions, suspensions can be found that include up to five levers. One of the lower ones is the carrier, holding the spring and the weight of the body. The shock absorber and spring can be installed separately or as a . An anti-roll bar also takes part in the work of the independent rear suspension Multilink.

Principle of operation

Multi-link suspension can be installed both on the front and on rear axle car. The upper and lower arms, independent of each other, are fixed on the body on one side and on the wheel hub on the other. The peculiarity of this suspension is that the wheel hub is able to change its position in the horizontal plane, improving the smoothness of the ride on uneven surfaces and increasing the vehicle's stability when cornering.

Animation of the Multilink five-arm suspension (top view) Animation of the Multilink five-arm suspension (rear view)

Advantages

Compared with a double wishbone design, a multi-link suspension has the following advantages:

• better stability car;
• excellent smoothness of the course;
• excellent cornering;
• independent transverse and longitudinal adjustment of the hub position angles.

Flaws

Cons due to the design features of the Multilink front suspension:

• bulkiness;
• complexity and high cost of production;
• less reliability.

The use of multi-link suspension

Cons of application Multilink diagrams for the front suspension in the form of an increase in the cost of the car and expensive repairs justified in production expensive cars. Additional arms of complex design with ball joints increase the cost of the entire suspension scheme. It is also necessary to provide for a complex structure of interaction of elements with greater mobility, especially when turning the wheel. In this regard, the front suspension of the Multilink type is not used in the bulk of passenger cars, in the production of which the main criteria remain low price, reliability and maintainability.

Diagram of the back lot linkage suspension 2015 Lexus RC

Multi-link suspension for rear wheels received most widespread. Compared to the complicated design for the front axle, where it is necessary to rotate the hub assembly, the cost of manufacturing the Multilink rear suspension is significantly lower. The only expensive element is a massive load-bearing lower arm that takes the main load. The rest of the rods and levers serve only as guides.

Scheme of the rear multi-link suspension Honda Civic

Multi-link suspension can be installed on mono-drive and four-wheel drive vehicles. Currently, it is widely used in the production of both passenger cars and crossovers. The progressive design combines the advantages of a two-lever scheme - stability and smoothness, improving them thanks to the separate arrangement of the guide elements. Multilink suspension improves vehicle handling and provides the best possible grip pavement.

Named after an American engineer Ford Earl Steele MacPherson (Earle Steele MacPherson), who first applied it on stock car Ford models Vedette 1948. It was later used for Ford vehicles Zephyr (1950) and Ford Consul (1951). It is the most common type of independent suspension, which is used on the front axle of the car.

In design, MacPherson strut suspension is an evolution of the double wishbone suspension, in which the upper wishbone is replaced by a shock absorber strut. Due to its compact design, McPherson suspension is widely used on front-wheel drive cars, as it allows you to transversely place the engine, gearbox and more attachments in engine compartment. The main advantage of this type of suspension is the simplicity of design, as well as a large suspension travel that prevents breakdowns. At the same time, the design features of the suspension (hinged shock absorber strut, large stroke) lead to a significant change in the camber (the angle of the wheel to the vertical plane). In a turn, the camber goes into a plus, the wheel seems to be tucked under the car, in connection with which the ability of the car to turn on high speed. This is the main disadvantage of MacPherson suspension, which is why this type of suspension is not used on sports cars and luxury cars.

MacPherson suspension has the following device:

1. spring

2. shock absorber strut

3. roll bar

4. wishbone with ball joint

5. subframe

6. knuckle

The suspension is attached to the body through a subframe, which is the supporting structure. It is rigidly attached to the body or through silent blocks to reduce vibrations transmitted to the body. Two triangular transverse levers are attached to the side of the subframe, which are connected to the steering knuckle through a ball joint. The steering knuckle rotates the wheel due to the steering rod, which is attached to it from the side. Shock absorbers with springs mounted on them are attached directly to the steering knuckle. Two rods from the lateral stability shock absorber, which are responsible for lateral stability, are connected to the shock absorbers through ball joints. As you can see, the suspension device is simple enough to describe it in 3 lines.

Pros and cons

pros

+ low cost

+ easy to maintain

+ compactness

- Poor cornering handling

- Transmission of road noise to the body

MacPherson strut video:

http://www.youtube.com/watch?v=I7XJO3F476M

2. Double wishbone suspension( Double wishbone suspension)

Unfortunately, it is still not known for certain who first invented the double wishbone suspension, it first appeared in the early 30s on Packard cars. This company was based in the heart of the American automotive industry - Detroit. The first Packard car rolled off the production line in 1899, the last one was built in 1958. After the 1930s, many american cars began to be equipped with a double-lever suspension, which cannot be said about Europe, because. due to the size of the car, there was not enough space to accommodate such a suspension. A lot of time has passed since then, and now double wishbone suspension is considered the ideal type of independent suspension. Because of their design features it provides better control behind the position of the wheel relative to the road, because double levers always keep the wheel perpendicular to the road, for this reason the handling of such cars is much better.

Double wishbone suspension can be used on the front and rear axles of the car. The suspension is used as the front suspension on many sports cars, executive and business class sedans, as well as formula one cars.

Double wishbone suspension device:

1. upper wishbone
2. shock absorber
3. spring
4. drive shaft
5. tie rod
6. lower wishbone

The double wishbone suspension design includes two wishbones, a spring and a shock absorber.

Lever arm may be Y-shaped or U-shaped. Unlike MacPherson, there are two levers, each of the levers is attached to the body through silent blocks and to knuckle through a ball joint. The upper arm, as a rule, has a shorter length, which gives a negative camber angle of the wheel in compression and a positive one in tension (rebound). This property gives additional stability the car when cornering, leaving the wheel perpendicular to the road, regardless of the position of the body.

Pros and cons

pros

+ perpendicular position of the wheel relative to the road in turns

+ peck resistance

+ improved handling

Minuses

- big size

- price

- laborious maintenance

Video of the double wishbone suspension

3. Multi-link suspension (Multilink).

Further development of the double wishbone suspension. This is the most common suspension on the rear axle at the moment. This is due to the fact that when using a double wishbone suspension when braking or releasing gas (on rear wheel drive vehicles) there is a change in the angle of convergence of the rear wheels. Because the suspension is attached to the subframe through silent blocks, which are deformed during braking and rear wheels start looking out. It would seem that this phenomenon is nothing terrible, but imagine that you went over the speed in a turn and decided to resort to braking, braking in a turn in itself is not a good idea. And then the external loaded wheel begins to look out of the turn, the car very quickly acquires oversteer and the consequences can be the saddest. You can prevent this phenomenon by replacing silent blocks with swivel joints, but then comfort will suffer greatly, because no one wants to knock their teeth on bumps. So the engineers went the other way.

Now installed on cars different types pendants. There is dependent and independent. Lately on cars budget class install a semi-independent beam at the rear and a MacPherson strut at the front. Business and premium cars have always used independent multi-link suspension. What are the pros and cons of her? How is it organized? All this and more - further in our today's article.

Characteristic

Multi-link suspension is installed on cars with rear- and front-wheel drive layout. It has a more complex device, therefore it is used on cars expensive class. For the first time, a multi-link suspension was installed on the Jaguar E-Tour in the early 60s. Over time, it has been modernized and is now actively used on Mercedes, BMW, Audi and many others.

Device

What are the features of this design? Multi-link suspension requires the following elements:

• Subframe.
• Transverse and trailing arms.
• Hub supports.
• Shock absorbers and springs.

How is it all fixed?

The hub is attached to the wheel by means of four levers. This allows the wheel of the car to move freely in the transverse and longitudinal plane. The supporting element in the design of this suspension is the subframe.

A transverse lever is attached to it through special bushings with a metal base. To reduce vibration, they use rubber. The cross arms are connected to the hub support. This is how it works correct position wheels in the transverse plane. Often, a multi-link independent rear suspension includes three wishbones:

• Lower back.
• Front.
• Upper.

The latter transfers forces and connects the subframe to the wheel support housing. The bottom is responsible for convergence. Rear element perceives the forces that are transmitted from the body when the car is moving. The steering of the wheel in the longitudinal position is carried out thanks to the longitudinal lever. It is attached to the car body with a support. On the other hand, the element is connected to the hub.

A passenger car has four trailing arms - one for each wheel. The hub support itself is the base for the wheel and bearing. The latter is attached with a bolt. By the way, if you do not observe its tightening torque, you can disable the bearing. When making repairs, you should leave a small play in the hub. Otherwise, the bearing will crumble. Also, the multi-link front suspension has a coil spring in its design. It rests on the lower rear wishbone and receives forces from it. A shock absorber is located separately from the spring. It is usually connected to the hub support.

Stabilizer

Multi-link, unlike a semi-dependent beam, has an anti-roll bar in its design. The name itself speaks for the purpose of the element. This item reduces roll when cornering at speed. Also, this parameter is affected by the stiffness of shock absorbers and springs. The presence of a stabilizer significantly reduces the risk of skidding when cornering, as it ensures continuous contact of the wheels with the road surface. The element is a kind of metal bar. It looks like the photo below.

Mounted on the subframe of the multi-link suspension and secured with rubber mounts. Thanks to the rods, the rod is connected to the hub support. What are the pros and cons of multi-link suspension? Let's take a look at them below.

Advantages

Cars with this suspension are much more comfortable. The design uses several levers. All of them are mounted on subframes through silent blocks. Thanks to this, when passing through the pit, the suspension perfectly swallows all the bumps.

By the way, only the lever of the wheel that fell into the pit works. If it is a beam, all efforts will be transferred to the adjacent hub. In a car where a multi-link suspension is used, there is no excessive noise and vibration when passing through bumps in the road. Also this car more safe. This is explained by the use of an anti-roll bar. In terms of weight, the levers are much lighter than the beam. This reduces the curb sprung weight of the vehicle.

Thus, a multi-link suspension is:

• Comfort.
• Absence of strong impacts on the body.
• Increased road grip.
• Possibility of transverse and longitudinal adjustment.

Flaws

If the question is raised about which is better - a beam or a multi-link suspension - it is worth considering the cons of the latter. Most big disadvantage is the complexity of the design. Hence the high cost of maintenance and the expensive price of the car itself.

The cost of a multi-link suspension is 2-3 times higher than a conventional semi-independent beam. The next one is resource. Since the design uses a lot of hinges, levers and stilentblok, they all fail sooner or later. The service life of multi-link suspension parts is 100 thousand kilometers. As for the beam, it is practically eternal. The design is much more reliable and does not require expensive maintenance. The most that needs to be replaced is the shock absorbers. They "walk" on our roads for about 80 thousand kilometers. Multi-link suspension requires more attention when driving over bumps. If the car began to make knocks in the front or rear, it is worth examining the condition of the levers and silent blocks. In the presence of gaps and freewheel they should be replaced.

The cost of new levers on the "Mercedes" in the 124th body is $ 120 per wheel. Despite the great age and low cost car, spare parts for it did not become cheaper. The same applies to other machines that use given type pendants. When you need a lift or a viewing hole. Typically, these machines are repaired in service centers. And these are additional costs.

Can you identify the problem yourself?

If you notice characteristic knocks while driving, the suspension may need to be repaired. To find out exact reason, you need a viewing hole or overpass. If this is the front suspension, inspect the condition. It has an anther. If it cracked, you need urgent replacement. Otherwise, all the dirt will get inside and you will have to buy new CV joint assembled.

Check play in tie rods. Check shock absorbers. If there are streaks on them, most likely, the sound comes from them. This means that the valve inside the shock absorber is broken and the stem moves arbitrarily. The silent blocks of the levers and the anti-roll bar should also not have any backlash. Inspection of the rear suspension should begin with shock absorbers. Next, check the traction. Often the elements are damaged in the area of ​​​​contact with the exhaust pipe.

Give this place Special attention. If the muffler hits the body, there are characteristic traces of impacts, it is worth replacing its pillow. In most cases, the problem disappears. After examining the condition of the suspension, summarize which elements are out of order and need to be replaced. In the absence of experience, it is recommended to contact the service.

Conclusion

So, we found out the features of the multi-link suspension. As you can see, it has many disadvantages. But its main advantage is comfort. The way this car drives is incomparable. It is also more agile. If there is a choice - a beam or a multi-link - it is worth starting from the budget. The last suspension should be taken only if you are ready to spend at least $ 400 on its maintenance.

Suspension is a set of devices that provide an elastic connection between the sprung and unsprung masses The 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 driving axle; 2 - support bracket; 3 - axle shaft; 4 - stabilizer; 5 - elastic element; 6 - shock absorber; 7 - suspension guide lever; eight - support post bracket

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 dependent suspension wheels and performed the function of an elastic and guiding device.

On passenger cars and trucks or minibuses, springs without springs are used, on trucks- with suspension brackets.

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 required characteristics provided with additional elastic elements made of polyurethane elastomer and rubber rebound buffers.

On passenger cars Russian production in suspensions, cylindrical helical springs with a constant rod cross section and pitch are used 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 elastic element and 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

Multi-link suspension has been installed on cars since the mid-twentieth century. It is currently the most popular. The suspension of a car consists of components and parts. It is designed to create an elastic connection between the car frame and its wheels. With its help, the load on the wheels and the body is reduced, it dampens vibrations, and also helps to control the position of the car body on the road when driving, especially when cornering. Thus, the suspension makes the car more stable on the road with a smooth ride.

A multi-link suspension is most often installed on the rear axle, but it is quite possible to install it on the front axle as well. In addition, it is installed on all types of drives: front wheel drive vehicles, rear wheel drive and with all-wheel drive. Multi-link suspension is a combined concept, as indicated by the name "multi-link". It does not have a clear design, but it combines the advantages of a double wishbone suspension with longitudinal and transverse levers. Thus, it was possible to achieve optimal kinematics and control effect. The multi-link suspension makes the car's movements smoother, reduces the noise level, and makes it easy to control the car on the road.

The design of the suspension consists in the fact that the wheel hubs are attached thanks to four levers, which allows adjustment both in the longitudinal and in the transverse plane. For correct operation suspension, it is necessary to correctly calculate the rigidity of the hinges and the compliance of the levers. To make the dimensions optimal, the suspension is mounted on a subframe. The design is complex and is done by computer.

The design of the multi-link suspension includes the following components and parts:

• subframe used for attaching levers;
• hub support;
• longitudinal and transverse levers;
• springs;
• shock absorbers;
• anti-roll bar.

The basis of the design is the subframe. To it are attached transverse levers connected to the hub support. They provide the position of the hub in the transverse plane. Their number can be from three to five. In the simplest design, three are used: one upper and two lower - front and rear.

The upper arm is designed to connect the wheel support to the subframe and transmit transverse forces. The rear one experiences the main load from the weight of the car frame, which is transmitted through the spring. The front lower is responsible for the convergence of the wheel. trailing arm fastened to the body thanks to the support, its function is to hold the wheel in the direction of the longitudinal axis. The other side connects to the hub support. Each wheel is equipped with its own trailing arm.

On the hub are bearings and wheel mounts. The bearings are attached to the support with bolts. Designed for suspension loads helical spring. Its support is the rear lower wishbones. One of the components of a multi-link suspension is an anti-roll bar, which serves to reduce body roll of the car when it is cornering. In addition, the stabilizer ensures good grip of the rear wheels with the road. The anti-roll bar is secured with rubber mounts. The rods are connected to the hub supports with special rods. Shock absorbers are connected to the hub support and are most often not connected to the spring.

Pros and cons

When evaluating the suspension, its consumer properties are taken into account: the stability of the car on the road, ease of control and comfort. Most often, motorists are of little interest technical details car. These questions are dealt with by the engineers who create it. They choose the type of suspension, select the optimal dimensions and specifications individual nodes. The machine undergoes many tests during development, therefore it meets all the requirements of the consumer.

It is known that comfort and handling are properties that are often opposite, as they depend on the stiffness of the suspension. You can combine them only in complex multi-link suspensions. The smooth running of the car is ensured by silent blocks and ball joints, as well as well-calibrated kinematics. When hitting obstacles, shocks are well extinguished. All suspension elements are attached to the subframe thanks to powerful silent blocks, so the interior is isolated from the noise of the wheels. The main advantage is manageability.

This pendant is used for expensive cars, providing good grip of the wheels with the road surface and the ability to clearly control the car on the road.

The main advantages of multi-link suspension:

1. the wheels are independent of each other;
2. low suspension mass, thanks to aluminum parts;
3. good road grip;
4. good handling when cornering;
5. possibility of use in the scheme 4×4.

Multi-link suspension requires high-quality roads, so it wears out quickly on domestic roads. The complexity of the design makes the cost of the suspension very expensive. Many manufacturers use non-separable levers on their models. Because of this, their cost is quite high.

Suspension diagnostics and repair

Multi-link suspension requires permanent care and if necessary timely repair. Despite the complexity of the design, you can check the condition of the multi-link suspension yourself.

For diagnostics, the car must be driven to viewing hole or jack up. During the check, you should have a car maintenance manual on hand, which describes its main parts and gives the necessary recommendations.

First of all, shock absorbers are removed, which are checked for cracks. Then the integrity of ball bearings, rods, levers, silent blocks is checked. All mounting bolts are checked and rubber seals. All parts must not have any damage. If damaged parts are found, they must be replaced: either independently, using the diagrams in the manual, or at a service station.

On the rear suspension, in addition to shock absorbers, it is necessary to check the traction and seals. Near rear suspension located exhaust pipe, which may be the cause of extraneous sounds. The muffler should be carefully examined, shake it in different directions, check the fasteners. These actions can remove the resulting extraneous sound.

If you regularly diagnose the car and carry out its timely repair, this will extend its service life and improve driving safety.

Video “Repair of the front multi-link suspension”

The recording shows how to replace the rear silent blocks of the front levers on a Ford Focus.