How the vacuum amplifier works. The principle of operation of a vacuum brake amplifier and how to check it. Principle of operation of a vacuum brake amplifier

It is difficult to imagine the work of the brakes without a vacuum brake amplifier. It is difficult to overestimate this device, however, it, like all other "not insured" from breakage. Today I suggest to talk about the main problems of the vacuum amplifier of the brakes and how to eliminate them.

On the one hand, the repair of a vacuum brake amplifier does not represent anything particularly difficult, if you decide to repair this device with your own hands. The most important thing to take into account all constructive features The concrete brand of the car, the principle of repairing the repair is not particularly different.

A little about the device of a vacuum brake amplifier.

A constructive vacuum brake amplifier is one block combined with GTC. For an advanced motorist, the device of this unit will not seem complex. The housing is divided into two parts: the vacuum part is located on the side of the main brake cylinder, atmospheric - from the side of the brake pedal.

The vacuum chamber is connected to the intake manifold using the check valve, which is the source of the discharge. Most often, the vacuum electric pump is used in diesel engines with the goal so that the operation of the vacuum amplifier is constant. In the case of stopping the engine, the vacuum amplifier is disconnected with the collector by means of the check valve, which is why the vacuum brake amplifier is very dependent on the motor operation and is able to function only when the engine is operated.

After activating the brake pedal by means of the tracking valve, the atmospheric chamber is connected to the vacuum chamber and the atmosphere. The brake pedal is associated with the pusher, at the expense of which the tracking valve is moved. The diaphragm is connected to the gtz stem from the vacuum chamber, due to it, the brake fluid is injected with a piston to the working cylinders.

Returning spring Returns a diaphragm in initial position After the end of braking. The design of the amplifier may also contain a stem electromagnetic drive. IN eSP system An active brake amplifier is used, its main purpose is to prevent overturning.

Possible malfunctions of a vacuum brake amplifier.

First of all, attention should be focused on ineffective work. brake systemthat is, the deterioration of management vehicle (TC), the need to make more efforts to produce braking. The following faults are considered classic:

1. Malfunctions within the vacuum amplifier itself (discrepance of the diaphragm or aging of the valve rubber). In this case, the valve will focus air.

2. Depressurization or complete hose breaking, which connects the engine collector with a vacuum brake amplifier. As a rule, such a fault is accompanied by the hiss of this device. IN obligatory Check the tightness of the clamps, as well as the hose for cracks and breaks.

How to independently check the vacuum brake amplifier?

1. If the motor began to work unevenly (with interruptions or troit), it is necessary to diagnose the health of the vacuum amplifier. Often, the depressurization is accompanied by sucking air into the air intake manifold nozzle, as a result, the air-fuel mixture entering the cylinders sharply departs.

2. As an option, you can try to diagnose a malfunction and such a macar: produce 5-6 swing brake pedal with a "dangled" engine. After that, in the middle of the course, make the pedal fixation, then run the motor. If the pedal failed during the start - the vacuum amplifier can be considered a worker. If the pedal remained fixed - repair or complete replacement of a vacuum brake amplifier is necessary.

3. Spend visual inspection, and carefully look care if there is no inclusion on the housing of the vacuum amplifier.

Repair of a vacuum brake amplifier.

In order to repair or replace, you need to have some skills and knowledge, it will not be superfluous to look into the manual for repair and maintenance of your car. In addition, you will need tools, as a rule, a fairly standard set.

Below you give you phased instructions Procedures for repairing a vacuum brake amplifier:

1. Read the leadership (manual) for the repair and operation of the car, determine the key nuances for yourself.

2. Disconnect the thrust of the amplifier drive from the brake pedal, which is located under the steering shaft.

3. Remove the GTC in the sub-compartment.

4. Depending on the breakdown, make repairs or full replacement This device.

3.7 (73.33%) 3 Voice [A]

Vacuum amplifier is one of the inalienable elements of the car brake system. His main purpose is an increase in the effort transmitted from the pedal to the main brake cylinder. Due to this, the car management becomes easier and comfortable, and the braking is effective. In the article we will analyze how the amplifier works, we learn from which items it consists, and also find out if it is possible to do without it.

Functions of a vacuum amplifier

The main functions of the vacuum (common designation of the device) are:

• an increase in efforts with which the driver presses on the brake pedal;
• ensuring more efficient operation of the brake system during emergency braking.

Additional effort vacuum amplifier creates due to the resulting discharge. And it is this strengthening in the event of emergency braking of the car, moving at high speed, allows the entire brake system to work out with high efficiency.

Device of the vacuum brake amplifier

A constructive vacuum amplifier is a sealed case of a rounded form. It is installed in front of the brake pedal in motor compartment. The main brake cylinder is located on its enclosure. There is another type of device - the hydraulic amplifier of the brakes, which is included in the hydraulic part of the drive.

The brake vacuum amplifier consists of the following elements:

1. housing;
2. diaphragm (for two cameras);
3. track valve;
4. pusher pedal brakes;
5. rod piston brake hydraulic cylinder;
6. return spring.

The body of the device is divided into two cameras: vacuum and atmospheric. The first is located on the part of the main brake cylinder, the second - on the side of the brake pedal. Through the reverse valve of the amplifier, the vacuum chamber is connected to the source of the discharge (vacuum), which on vehicles with a gasoline engine, use the intake manifold before fuel supply to cylinders.

In the diesel, the source of the discharge serves an electric vacuum pump. Here, the discharge in the intake manifold is minor, so the pump is a mandatory element. The reverse valve of the vacuum brake amplifier discovers it with a source of discharge when the engine is stopped, as well as in the case where the electrovacuum pump has failed.

The diaphragm is connected to the piston rod of the main brake cylinder side of the vacuum chamber. Its movement provides the movement of the piston and discharge the brake fluid to the wheel cylinders.

The atmospheric chamber is connected to the vacuum chamber, and when the brake pedal is pressed - with an atmosphere. The message with the atmosphere provides a tracking valve, the movement of which occurs with the pusher.

In the design of the vacuuman in order to increase braking efficiency in emergency situation It can be included in the form of an additional stem electromagnetic drive.

Principle of operation of a vacuum brake amplifier

Works a vacuum brake amplifier due to different pressure in cameras. At the same time, in the initial position, the pressure in both chambers will be the same and equal pressure generated by the source of the discharge.

When you press the brake pedal, the pusher transmits the effort to the tracking valve, which overlaps the channel connecting both chambers. Further valve movement helps to connect the atmospheric chamber through the connecting channel with an atmosphere. As a result, the discharge in the chamber decreases. The pressure difference in the chambers moves the piston rod of the main brake cylinder. When braking ends, the chambers are again connected and the pressure in them is aligned. The diaphragm under the influence of the return spring occupies its original position. Vacuum works proportional to the strength of pressing the brake pedal, i.e. The stronger the driver will press the brake pedal, the more effective the device will work.

Vacuum amplifier sensors

Efficient operation of the vacuum amplifier with the highest coefficient useful action Provides a pneumatic emergency braking system. The latter includes a sensor, measuring the speed of moving the rod of the amplifier. It is located directly in the amplifier.

Also in the vacuumnik there is a sensor that determines the degree of discharge. It is intended for signaling about a lack of vacuum in the amplifier.

Conclusion

The brake vacuum amplifier is an indispensable element of the brake system. Without it, it is not necessary to do without it. First, you will have to spend more efforts in braking, you may even have to harm the brake pedal with two legs. And secondly, riding without amplifier is unsafe. In case of emergency braking, it may simply do not have enough braking path.

Principle of operation of a vacuum brake amplifier

How does a vacuum brake amplifier work? The solution is elegant enough and uses the resource that we have "under your feet", and even more precisely - "above your head." Remember, Ostap Bender spoke of a big air column, which gives each person? So, he presses and seriously enough for everything around. We do not notice this, due to the fact that we have internal pressure. Tires have to be punished to create pressure more atmospheric. And remember that it will be with a tin can if you pump out from it? That's right - the atmospheric pressure will make a "bun". Or Magdeburg Hemispheres, who could not break two horses harms? Atmospheric pressure power is very large. Let's try to apply it for peaceful purposes - to enhance the brake. You have already understood that in order to use it, and she began to act, from a certain camera should be removed the pressure of the air or easier - it should be daddy. Or on the one side of the body, you need to create a pressure of less atmospheric (aircraft fly so much, by the way, and therefore the principle of a twisted ball flies on a curved trajectory). Otherwise, according to the third law of Newton, the force of action will be equal to the strength of opposition, and nothing will happen. We now take a hermetic chamber and supply it to the membrane, dividing the camera into 2 parts. We put in one half a "smart valve" that will open when we need, connecting this half camera with the atmosphere. Close this valve. And in the membrane, we will also make a valve that will initially be opened. Those. Both halves will be freely reported.

Source Source in Vacuum Amplifier - Engine

Now turn out air chamber. There will create a vacation, in both halves the same, thanks to the open valve. Nothing will not happen. Now let's close the valve between the camera halves and launch the atmosphere in one of the halves. It is not difficult to guess that all the strength of the atmosphere will go to the membrane and starts to put pressure from it inherent in 10 with a small ton (!) On a square meter. The membrane will move and carry out the work we need due to the force of atmospheric pressure, and not our own. What are we cunning with you. Now it remains to attach the rod to the membrane and combine it with the main brake cylinder, which serves brake fluid In working cylinders, which, in turn, move brake pads. And from the second side of the membrane, connect the rod to the pedal and our atmospheric valve. And on the opening of the valves, we need a very small effort. It will even have to strengthen it, to feel the effort of braking.

Now that braking is performed, we stay with the back movement of the pedal to close the atmospheric valve and open connecting our halves, the valve. From the cameras again pumps air? And recovery will be restored in the entire chamber. The system is again ready for braking! It remains to come up with how to support the vacuum. Engine internal combustion Consumes or even "sucks" air for combustion of fuel with great voraciousness. Accordingly, in the intake manifold (this is a pipe for which the engine sucks air) will be a decent vacuum. Now simply connect it, again, through the "smart" valves, with the camera amplifier. And when we need it, we will open the valve, and the engine itself will suck all the air from the amplifier chamber. Elegantly? Of course. But sometimes they still put a special vacuum electric pump to eliminate the uneven air intake collector, especially for diesel engines, where negative pressure is very small. What will happen if we turn off the engine or turn off the vacuum pump? Recall that the membrane is connected and with the main brake cylinder and with the pedal. Mechanical (kinematic) Sound is not lost! Our pedal will move directly the main cylinder, as before, at the same time causing an already useless discovery / closing of the corresponding valves. The gain will not be. On both sides of the membrane will be the same pressure, thanks to the special reverse valve, which will turn off the vacuum line when the engine is turned off or the electric pump. Yes, the effort will be significantly higher, but you can reach the service.

Scheme of vacuum brake amplifier

And now, when you all know, look at the real amplifier scheme

1 - flange of tip mount; 2 - rod; 3 - Return spring diaphragm; 4 - sealing ring of the flange of the main cylinder; 5 - main brake cylinder; 6 - hairpin an amplifier; 7 - the amplifier housing; 8 - diaphragm; 9 - the lid of the amplifier housing; 10 - piston; 11 - Protective Case Case Valve; 12 - pusher; 13 - Return spring pusher; 14 - Spring valve; 15 - tracking valve; 16 - stock buffer; 17 - valve body; BUT - vacuum chamber; IN - atmospheric chamber; C, D. - Channels.

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The vacuum brake amplifier provides better dynamics of the car slowdown and significantly increases the level of control of the controls. In practice, work is recorded with efficient braking with a minimal effort to press the pedal. Application active systems Assistance in emergency braking significantly improves road safety.

Device VUT.

Vacuum brake force amplifier in most cars is located near the engine shield and is a monolithic block with GTC and a brake fluid tank.

To enhance brake efforts in the design of the VUT are used:

• metal case;
• separation diaphragm made of plastic material;
• check valve;
• pusher pedal node;
• track valve;
• hydraulic cylinder rod;
• return Spring.

Principle of operation

Putting force brake shoes In cars, the design of which does not involve the installation of the VUT, injected with force, created by the driver When you click on the pedal. The brake vacuum amplifier uses atmospheric pressure difference to create a discharge, thereby helping the pressure in the brake line.

Let's start with the fact that the working diaphragm separates the housing to the atmospheric and vacuum (located on the side of the GTC) of the chamber. It is connected through the pusher with the pedal. When the brakes are not involved, the tracking valve supports equal pressure in two chambers. Pressing the brake pedal causes the tracking valve "cuts" the connection. Bypass valve equalizes the pressure of the atmospheric part of the housing with the subcontrol space. The vacuum that all this time was supported in the VUT housing, now attracts a diaphragm. As soon as the driver releases the brake pedal, the return spring returns the elastic partition into its original position.

Low pressure in the housing, which drives the vacuum amplifier, is created through a hose connecting the vacuum part with the intake manifold. It occurs due to the discharge, created by the piston descending into NMT, during the intake of the fuel and air mixture. If Vakuuma gasoline engine enough for normal work wat, then diesel engines necessarily equipped with vacuum pump, designed to push the discharge. Depending on the design (petal, membrane), in motion, such a device leads: TNVD, the generator either camshaft.

Breakdowns VUT.

The malfunction of the vacuum amplifier can affect not only the efficiency of the brake system, but also to the operation of the gasoline engine. The main types of breakdowns include:

• disorder of system tightness, hose damage to ensure discharge;
• tensile a diaphragm;
• damage to working valves or related parts (springs, valves).

The pretext of the brake pressure amplifier does not deprive the brake car, but it can significantly make it difficult to control the vehicle.

If you notice changes in the work of the amplifier, do not rush to change the hose or repair the brake amplifier. On some cars, the air recycling valve in the cabin is directly related to the work of the amplifier. The symptoms of the depressurization of this system are similar to those that manifest themselves during the breakdowns of the VUT.

Independent diagnosis

The simple principle of work allows you to perform diagnostics with your own hands. Repair of a vacuum amplifier should be entrusted to specialists. Several simple methods will help you to identify the serviceability of the system:

• after the engine's short work, stop the car and press the brake pedal several times. With a good amplifier, the first press will be easily, and all subsequent will require effort. Each subsequent pedal move will be shorter;
• mustle the engine and wait a few minutes. You can check the wout on tightness by pulling the hose that goes to it from the intake manifold. In the presence of discharge you will hear the cotton of emerging air;
• on the plugged engine several times in a row vigorously press the brake pedal. Get the engine while continuing to hold the pedal. As soon as the engine starts, a serviceable vacuum amplifier brake system will make a "soft" pedal, and it fails;
• one of the most common problems is the "SUPPLC" air. Check the discharge supply hose for mechanical damage, as well as the tightness of the location of its connection with the case. In this case, urine repair may be required. Such "supply" air is quite enough to petrol motor started troit;
• the engine is muffled. When you first click on the pedal, the sound of the air case is included in the atmospheric part. If there is no such, the membrane is torn or the bypass valve is defective.

The listed features of the brake force amplifier malfunction will help you diagnose and eliminate the breakdown in the shortest possible time.

The main factor in the malfunction of the vacuum brake amplifier is its complete or partial inability to create a vacuum in the working chamber. The potential source of the problem is the breakdown or depressurization of the hose connection, connecting the inlet engine manifold and amplifier.

Interference in the work of the unit is caused by defects inside the amplifier - due to disruption of the integrity of the working surface of the diaphragm or loss of the valve elasticity. In order to detect the malfunction of the vacuum brake amplifier, certain tests are carried out.

Methods and signs of malfunctions of a vacuum brake amplifier

1. For example. Start the engine, and after a few minutes to drown it. Then no time with the usual effort to press the brake pedal. With a good amplifier at the time of the first press, the pedal will discourage, as it should be left. The system will work, and the vacuum created will attract a diaphragm that helps to push through the rod piston of the main brake cylinder.

   Then the valve compares the pressure in the chamber with atmospheric. During the second and subsequent pressures of the pedal, the discharge will be resting will be nowhere, why the pedal move will become less and less. If there is no difference between the initial and further presses on the pedal, it is clear: this appliance additional force in the main brake cylinder does not provide.

2. Following the experience done, it is necessary to fulish one more. The engine is turned off. Pedal brakes have been pressed any other time. Her point of something witnessed. Either the results of the experiment seemed inconclusive, or a desire to produce a test approbation. The following actions are manufactured. The brake pedal squeezes, and the engine starts when the pedal is started.

   With a working vacuum amplifier, a discharge is formed in its vacuum chamber, because of which the membrane presses on the rod, the rod pulls the pusher connected to the pedal, and the latter is slightly lowered.

   In the case when the pedal remains on the spot, the output is made: the expected chain of events did not take place due to the malfunction of the vacuum brake amplifier. Such checks are detected by essential versions of the part.

3. Another test makes it possible to determine the presence of small air leaks. When the car's motor is running, you should click on the brake pedal, after which, without releasing it, drown out the engine. Hold the pedal in the same position for half a minute.

   Due to the disruption of the tightness of the amplifier, the pressure in the vacuum chamber will increase. The diaphragm under the influence of the return spring, having lost the support of the force that balancing her position will put pressure on the pusher, and raise the brake pedal.

If this is not observed, it means that there are no malfunctions, and the vacuum brake amplifier works fine. In any case, in the event of the need to repair, any brake knot occur, it is taken into account that the second chance of the repair may not be introduced, therefore, for assistance in diagnosing and repair, they turn to professional professionals. They can produce.