Shock absorbers - what is it in a car? Principle of operation and features of shock absorbers

In the current information and automobile age, any person knows that the ergonomics of the machine is largely determined by shock absorbers. This is an indispensable part of the suspension of a modern car. How do different manufacturers of shock absorbers compete in the car market? Reviews of motorists to some extent reflect this phenomenon. After all, the picture of this competition for the consumer is very curious: American, German, Japanese companies set the tone for him. As a result, single-tube shock absorbers dominate the two-tube ones.

Briefly about the current market of shock absorbers

The annual Russian premium "Autocomponent of the Year" allows you to determine the most successful brands in each nomination. So, in 2016, from the Russian shock absorbers, the leading brand was "DEMFI", which presented racks and shock absorbers of the budget class "Comfort" series of improved quality "Premium" and "Drive". The company's products - front and rear shock absorbers VAZ, IZH, Lada, Ford Focus2, Renault Logan. Today, "DEMFI" is a small company (employing less than 60 people), but a high-tech and science-intensive one that can expand production provided that there is adequate demand.

The shock absorbers of UAZ "Hunter" from the Petersburg enterprise "Plaza" also deserve high praise. They are possible in three versions: "standard", "sport" and "extreme". Among foreign, the first-fourth places were won by the brands Monroe (USA / Belgium), TRW (Germany), KYB (Japan) and EGT (Lithuania), respectively.

How to understand an amateur novice, which shock absorbers are better? After all, the world's leading manufacturers are showing ever more sophisticated developments of the international class. For example, only Monroe today enters the market with various brands of shock absorbers: "reflex", "sensational track", "originals", "adventure", "van magnum". They are currently dominating the modern car market. A sign of the high reputation of the company Monroe is the complete set of its shock absorbers, recreated directly on the conveyor of Ford, Nissan, Renault, Mitsubishi, Volvo, Porsche.

German automotive industry uses mainly domestic shock absorbers. Reviews of motorists testify that Opel, Mercedes, Audi traditionally use the products of the concern ZF (which owns brands Sachs, Boge, TRW). The original shock absorber "Toyota", "Mitsubishi" is the products of the Japanese company KYB (brand KAYABA). However, this brand is becoming more popular both in the New and in the Old World. Currently, the following series A are imported: Premium oil, Excel-G gas oil, Gas-A-Just gas, Sport Ultra-SR, adjustable AGX, off-road Monomax.

What kind of shock absorbers "Hyundai" (Korean company) puts on their cars on the assembly line? It's logical that from another Korean company that produces auto components. And (this is a feature of Korea), relatives control both firms. The manufacturer of shock absorbers under the brand MANDO is called Halla Group. Its factories operate in Korea, India, Turkey, China, Poland, the USA. For a year tens of millions of dampers are manufactured. Install on their conveyors MANDO-shock absorbers "Ford", Peugeot, Nissan, BMW, Suzuki, Renault, GAZ. It is significant that the shock absorbers of the KIA (another Korean autocorporation) are also supplied from the company Halla Group.

The competition of brands

The competition of producers is so significant that the imported brands successfully oppose the local ones. In particular, some drivers prefer Japanese cars to European cars. So, according to the owners of vehicles, at present the gas-oil shock absorber "Renault" produced by the company Kayaba is in high demand.

It is preferred for most of the current models of this brand: Kengo, Megan, Traffic, Premium, Master, Clio, Laguna, Magnum, etc. Its price is 30% Above the cost of the oil device, but it is noticeably more effective when driving on a rough road. Therefore, the gas-oil shock absorber "Renault" drivers prefer oil, cheaper.

Note that the model "Renault", designed for extreme driving along high-quality tracks, are equipped with special shock absorbers - Kayaba Ultra SR. After all, speedy overcoming of turns determines a big load on such products, both compression and release. However, for everyday urban traffic, they are not optimal, because they have increased rigidity, and for imperfect roads, as is known, we need milder springs.

However, in this article we will not limit ourselves to the review of the shock absorber market. Our goal is to expand the secrets of their successful exploitation. As is known, shock absorbers are the providing elements of suspension, respectively, imagine an ideal suspension. As you know, this element performs two tasks:

• First, connects the car wheels to the body. Thanks to it, the clutch of wheels with the road is necessary for full-motion.
• Secondly, it neutralizes (amortizes) the fluctuations that have arisen during the movement.

Amortization is ...

With a closer look at the suspension elements, it becomes clear that the shock absorbers are dampening (damping vibrations) devices. At the dawn of the automotive industry (XIX - early XX century), the mentioned details did not exist at all. At low speeds of the first cars, the balance of the suspension was sufficient only for the springs. However, in the modern dynamic age of speeds in the suspension there are not only improved springs (springs), which nowadays are often called somewhat abstract - elastic element. This is not enough. To illustrate what has been said, let us consider a typical case of overcoming a road bump by a car.

In this case, the problem of the elastic element is obvious - when the wheels hit the unevenness of the road, it must soften this blow. However, the modern car with the movement has a huge kinetic energy, with the "freewheeling emissions" of which on the potholes of the road, the elastic element does not cope at all. Therefore, the inertia of the body causes the springs to oscillate after the collision. This is an extremely undesirable effect. After all, it can lead to a resonance that can lead to a car accident (remember the physics and vectors of force). This happens when the oscillation of the spring from the next unevenness of the road develops with its previous oscillation, which, alas, has not been extinguished. Engineers have responded to this phenomenon properly by inventing a special damping device.

At the beginning of the 20th century, a damper (shock absorber) was created to cancel the vibrations of the elastic element. The idea of his work was quite simple and elegant. After the unevenness of the road causes the spring to contract, its subsequent expansion and, accordingly, oscillation, will extinguish the special device - shock absorber. However, we will not consider it as the only detail that protects against vibrations, because for the ideal behavior of the machine on the road, only a shock absorber and an elastic element is not enough.

Not shock absorbers united

The aforementioned shock absorbers are special elements for maintaining the maximum possible horizontal and stable suspension position in space. But for a truly workable suspension this is not enough. For the maximum comfort of passengers and the driver, so that the car does not consider bumps, but smoothly hovered along the route, the coordinated work of shock absorbers and other devices, such as:

• Tires from excellent rubber, ensuring proper grip with the track;
• Non-sprung springs and suspension springs (except for the functions already mentioned) must maintain the clearance indicated in the technical specifications and keep the machine at the same level;
• Additional rubber-metal elements (hinges and compression buffers), suppressing vibrations from touching metal parts to each other;
• The guiding devices that determine the desired angle of rotation of the wheels.

However, anyway, the main damping device of the car are shock absorbers - the subject of the description of this article. With their help, the harmony of constant contact of the wheels with the roadway is achieved (the car goes, as if tied to the road), and, in principle, it becomes possible to really comfortable driving.

What is the shock absorber in appearance?

Outwardly it looks like a cylindrical device, attached to one side of the car frame, and on the other - to the suspension. The piston moves inside the shock absorber. It is a rod moving in a cavity filled with gas, oil or brake fluid. Due to the tightening of the oil, the piston reduces the speed of its movement. The suspension oscillations determine the vibration of the shock absorber piston. The more actively the suspension moves (which happens on an uneven road), the greater the resistance the shock absorber demonstrates. Various impacts, obtained when driving a car on an uneven road, as well as fluctuations during sudden braking or at the beginning of movement, are damped (softened) by a shock absorber. In this case, the kinetic energy of the oscillation becomes thermal, which is obtained when the piston compresses the oil. The resulting heat is dissipated.

The depreciation process

How does the shock absorber react when the wheel collides with a road pothole? He shrinks, kicking the blow, while his piston works in concert with the springs of the suspension. However, the cycle of operation of the device does not end there, since its expansion occurs, i.e., the piston is pulled out from the shock absorber. Without it, the suspension springs would throw the car's body upward with the same force as when they collided with a pothole. However, the movement of the piston of the shock absorber of the car, working on the expansion, is also inhibited by oil.

Design of shock absorbers

Technically, the device during its operation transforms the mechanical vibrations of the elastic element into thermal ones. Replacement of shock absorbers, exhausted their resource of effective use, is a responsible matter. After all, the installer "new thing" immediately notices changes in the behavior of the car. Therefore, for a knowledgeable driver, the proper selection of shock absorbers is critical. And to choose, believe me, is from what. The car market is saturated with the corresponding products of famous brands (brands) and not very much. We will return to this aspect of coverage. But at first it will be logical to digress from the principle of "who will be" and try to "see to the root", that is, to understand the fundamental differences between different types of shock absorbers (A).

Judging by the structural differences, A is subdivided into one- and two-tube. If, on the other hand, it is classified according to the type of working substance that dissipates the heat obtained after the conversion of the kinematic energy, the shock absorbers are oil, gas-oil and gas.

Two-pipe products

What kind of shock absorbers can I recommend for quiet, so-called family driving? Relatively inexpensive, simple in design, which does not withstand extreme. Two-tube A are more inert and have a greater mass. In addition, the double casing is worse cooled. In this case, the effectiveness of the damping of two-pipe devices depends on the correct installation. As you know, the shock absorber, which is fixed strictly perpendicular to the suspension, fulfills its functions 100%, but if this angle increases to 50 °, then its efficiency drops to 68%.

The design of such elements includes a working flask, inside which the piston is located, as well as an outer housing intended for storing excess oil. During its working cycle, the piston passes a part of the oil through its channels, and also squeezes it out through the compression valve located at the bottom of the bulb. When buying products, you should pay special attention to the oil, which should not boil at temperatures below 150 ° C. In this case, despite the favorable price, they should not be installed on cars of the latest generation.

Single-pipe shock absorbers

This design is the basis for modern A. This shock absorber consists of a single bulb, simultaneously acting as a working container for the piston, and the body. It can be hydraulic (oil) or hydropneumatic (gas oil). The last modification is also called combined. The principle of oil-A is quite simple. There is a working cylinder filled with oil (hydraulic fluid). It moves a piston with special calibrated valves, more precisely with their system, having characteristics specially selected for the suspension of a certain model of the car.

The dynamics of this shock absorber is as follows:

• With the valves closed, the hydraulic fluid passes only by the bypass channel of the piston. The hydraulic characteristic of the shock absorber becomes rigid at the same time.
• If the valves adjacent to the compensation chamber A open, then its hydraulic characteristic becomes softer.

And for the serviceability of the shock absorber, the valve, which acts on the compression, must pass more hydraulic fluid than the non-return valve that is activated at the end. Thus, with the piston valves open, the stiffness of the shock absorbers decreases.

Combined shock absorbers

In hydropneumatic (gas-oil) shock absorbers, instead of air, compressed gas is used at a pressure of 4-20 atmospheres. Its motorists are called in their own way - "gas support". And the gas pressure is not a whim, but a way to reduce aeration (mixing of air and oil), as well as an additional element of elasticity of the suspension. Single-tube A does not have a lower compression valve. The piston completely controls the resistance both during compression and during retreat. They can accommodate more oil than in the two-pipe of the same volume, and therefore, with their help achievable better damping.

Controlled and magnetic shock absorbers

The leading manufacturers of shock absorbers are trying to solve the technical problem of regulating such devices rather ingeniously. The American-Belgian company MONROE manufactured special adjustment grooves on the walls of the working cylinder of the single-tube A, used to adjust to quiet or active driving. Japanese company KYA in the lower part of the single-tube with a remote reservoir A around the piston mounted a separate control valve. German concern ZF has created the operated shock-absorber "Opel-Astra", using a two-pipe gas-oil design. Two solenoid valves at the bottom of the shock absorber and in the piston are controlled by a special processor that monitors the parameters of the wheels, steering, suspension.

Even more promising is the new, so-called magnetic shock absorber "Chevrolet", installed last year on the model Chevrolet Corvette. This is a joint future development of the auto concern and the Delphi corporation. Used in them instead of oil, the magnetorheological liquid is capable of changing its viscosity under the action of an electromagnetic field at a high frequency (up to 1000 times per second). In this case, the valve system is not used in principle: damping is performed solely due to the magnetorheological effect. Such a design is very promising: there is no need for transverse stabilizers, the device of A itself is simplified, and there are also impressive possibilities for controlling and controlling the rigidity of the suspension.

Correspondence of the hydraulic characteristic of the shock absorber to the relief of the road

The design of the shock absorber should take into account various aspects of its operation. After all, poor-quality road surface determines the different modes of its operation. On the one hand, repeated small irregularities do not allow A to straighten out. In this case, the soft hydraulic characteristic is relevant. Large potholes threaten full forced compression, which often causes damage to the shock absorber. At the same time, the rigid hydraulic characteristic of the device is in demand.

Therefore it makes no sense to ask: "Which shock absorbers are better - soft or hard?" After all, the actual in terms of long-term operation A is not only their softness, but also controllability.

Another characteristic - the heat dissipation of the shock absorber - is important for its correct operation. After all, under conditions of a hard heat regime, more is released, and it should be diverted. On the other hand, in winter the oil in the shock absorber thickens, and its hydraulic characteristics become more rigid. Thus for the motorist the correct choice of oil becomes important. It is undesirable to use liquids with a high content of additives, because the latter have the property of softening the rubber. Most experts recommend the use of proprietary oils GRZH-12, AFT. However, in a frost, a liquid with a viscosity of 75Wt should be chosen. For oils containing silicone, the viscosity is determined in other units - cPs, which are about 10 times larger than Wt.

Diagnosis of shock absorbers

Because there is nothing eternal, the shock absorbers are also subject to wear and tear. This phenomenon should be diagnosed by the driver in time. As is known, replacement of lost shock absorbers must be performed immediately to identify them. And the most effective is the complex replacement of A: pairwise on each axis - both on the front and on the back. It is naive to expect after an incomplete replacement of shock absorbers of ideal damping.

However, this alone is also not enough. It is necessary to diagnose the whole complex of car devices involved in damping. After all, normal operation of shock absorbers is possible with serviceable rubber-metal elements (hinges and compression buffers), non-matched springs and springs. Maintenance of all the above parts and mechanisms will reduce the load on the shock absorbers.

When to replace

For the driver there are first signs indicating the wear of shock absorbers. Let's call them:

• Increase in braking distance due to deterioration in handling;
• Decrease in comfort speed for entry into the turn;
• Reduction of the safe speed of aquaplaning (adhesion to the track, if there is water on top of the ice);
• Worn out A begin to make sounds when the car enters the turn or overcoming unevenness.

When the shock absorbers break

Modern autocorporations make more and more efficient A, maximally bringing comfort to the trip. However, if on concrete routes they serve 80 and more thousand kilometers of the way, poor-quality road surface with potholes leads to unpredictable breakage of the mentioned devices much earlier.

Breakdowns occur most often inside the shock absorber when the car's wheel hits the pothole. From them begins to leak oil. Stems deform the shock, and in soft shock absorbers the valve in the working chamber is knocked out. Such breakdowns mean A failure and require unconditional replacement. Therefore, motorists weigh everything "for" and "against", buying shock absorbers. Reviews of drivers in this case, posted in special forums, should also be taken into account.

Spoil A can also the dust and dirt that gets into them. Small particles, hitting the working chamber, leave scratches on the rod. As a result, the stuffing box is no longer sealed, and as a result, oil leakage occurs. Even more perfect single-tube is A with a remote compensation chamber. The improved design allows the use of a larger volume of compressed gas and oil. With an even more advanced improvement in the way of the oil flowing from the main cylinder to the remote chamber, a system of valves adjusting the stiffness of the shock absorber is installed. There are modifications A, where over the outer surface pass the tubes for oil flow.

Conclusion

Today's car enthusiast is quite easy to choose the right shock absorbers for his car. At the same time, you can use the services of both a specialized traditional and an online store. For the convenience of customers, the choice of the shock absorbers they need begins on the website of the online store with the model of the car. After this simple manipulation, the buyer sees which brands and brands shock absorbers fit him. If he further doubts the choice between alternative brands, then he will be helped to form opinions of numerous reviews of motorists at specialized forums and all sorts of ratings.