What is a viscous coupling. What is the Vussft: the device and the principle of work

Viscounts, or, as it is also called, a viscous clutch, being part of a car transmission, is a mechanism for transmitting and equalizing the torque of the wheels. Its mainly difference from such aggregates as hydromefta and the hydrotransformer is that the torque is transmitted due to the use of unique viscous properties of special fluids, which is fill in the Viscounts.

Used as an auxiliary mechanism for automatic blocking of the wheel differential.

Viscounts - far from a new invention. The prototype was created back in 1917 in the United States. Inventor - Melvin Severn. The invention was ahead of its time, since it was not found to be applied, and only in 1964 the Viscounts were used for the first time - it was established for direct purpose - as a block inter-axis differential on the english car Interceptor FF. Since then, the Viscounts have been widely used in self-locking differentials on passenger cars with constant fully drive All wheels.

The Viscouft consists of several sets of discs, which are inside the metal case. A set of disks includes host drives (connected to the drive shaft), and slave discs (connected to the slave shaft).

On the surface of the discs there are special protrusions and recesses. The slave and drives are located apart on a very small distance. Inside the coupling is filled with a special dilatant liquid on a silicone basis, which has a unique feature - strongly thicken and expand with intense stirring.

How the Viscounts works

In the process of uniform motion, both shaft - the presenter and driven rotate at the same speed. In this case, the fluid inside the viscous coupling is not mixed, and it does not have any impact on the disk package. If the speed of rotation of one of the shafts changes, the discs begin to rotate. Liquid inside the Viscouft begins to mix, its viscosity is growing rapidly. If the difference between the speed of rotation of both shafts is sufficiently high, the liquid inside the coupling becomes so viscous that resembles a solid. As a result of the Viscounts, it is blocked, as a result of which the transmission of torque from the drive wheel to the slave reaches a maximum.

What fluid is poured into the Viscuft. What role does the viscosity of fluid play when the Viscounts

The body of the Viscounts has a cylindrical shape, it is completely sealed, and about 80-90% is filled with a special silicone-based liquid, which plays the role of a binder element between the discs. Silicone fluid (scientific name - siloxane, silicon organic polymer) has the highest kinematic viscosity. In this case, there are no lubricating properties, which allows this substance to tight discovers with each other, provided that they rotate with different angular velocities.
As a result of painstaking work, scientists managed to create a silicone liquid with truly unique properties. In most liquids in the heating process, the viscosity begins to decrease, and Siloxane, on the contrary, becomes more dense, until it becomes the properties of the solid. Due to this feature of the Viscounts, the torque can transmit the torque at different speeds of the rotation of the parts due to the viscosity of the silicon fluid.

So, if corner speeds The parts moving inside the parts do not coincide, the silicone fluid is stirred intensively, which leads to a sharp expansion of its volume and an increase in viscosity (with a coefficient of 2 for every 450 bar).

Viscous food and the system of the full drive, as the Vussochet works, and where is installed

This unit is applied in automatic all-wheel drive systems. Under normal driving conditions, the effort from the engine operation is transmitted only by one axis The second axis is connected directly through the viscous coupling, but it works in free progress mode, that is, disabled from the engine. If the host axis starts to slip, the Viscounts are blocked, and the motor force extends to the slave axis.

One of the main flaws of the Viscouft is relatively for a long time Triggering - the unit allows slipping of the wheels before they are locked, and the engine will transfer to the second axis. Especially good it is felt when operating automatic full drive systems. So, if you add gas sharply, passing, for example, a slippery rotation, the main axis will begin to demolish, and only then, with some delay, the second bridge is turned on. The behavior of the car changes dramatically. When starting from the place on the sand, the wheels of the driving axis can thoroughly burst before working the axis will work.

To reduce blocking time, manufacturers use different gear ratios in gearboxes, which causes the slave and leading shafts to rotate at different speeds, stirring the binder liquid. Thus, it is possible to create a preload of the Viscounts. However, too much preload creates a lot of transmission voltage, as a result of which the car becomes too sensitive to different generation of wheels on the leading and slave axes.

How to check the work of the Viscounts in the transmission system

The most reliable results can be obtained using a test produced on a roller stand, or, as it is also called, "on the drums". In the process of testing ahead and behind the car there should be no extraneous subjects. Standing in front and behind the car is also categorically prohibited.

The algorithm of action is as follows:

The first transmission turns on, engine speed is adjusted to 1500 rpm. In this mode, the operation of the Viscounts should not be blocked.

With an increase in the engine speed, over 1500 Viscounts should be blocked, while the car should move from the stand.

If the Viscounts are not blocked when the engine revolutions from 1500 to 2500 rpm, it means it is unfamiliar and needs to be replaced.

Control of free stroke is checked as follows:

A lift and one helper are needed.

The car is applied to a height of about 1 meter from the floor.
Together with the assistant at the same time begin to turn forward rear wheels. The front wheels should remain fixed.
Next together with the assistant turn the rear wheels to the side rear stroke. In this case, the front wheels must be turned synchronously with the rear.

To check the system of the interstole blocking, you will need two assistants. Procedure Next:

Since a vacuum is needed to trigger the lock system, you need to start the engine for about 30-40 seconds on idling, after which the engine can be drowning.

One man sits in the cabin behind the wheel.
The car is lifted by about 1 meter from the floor.
The assistant includes the ignition (you do not need to start the engine), turns on the rear speed, the clutch squeezes the stop.
Two people begin to simultaneously turn the rear wheels in different directions.
If you cannot turn the wheels, the problem may not only be in a faulty Viscounts, and in electrical wiring, pneumatics, or rear differential mechanics.

The cooling radiator wedge, as it works, where installed

The work of the Okhljadia Radiator Viskors directly depends on its device, thanks to which the fan does not work constantly, but depending on the temperature of the coolant.
Due to this, the cooling system works as efficiently as possible.
The cooling radiator viscouft consists of a solid body having an oval shape.
Inside the case there are two disks. One drive is rigidly attached to the coolant impeller shaft. The other is attached directly to the shaft, which is connected to the drive from the engine. Disks "float" in a special silicone fluid. The design of the Viscouft also includes a special bimetallic plate.

The whole system works as follows:

If the air temperature is normal, both disks are either at a minimum distance from each other, or slightly engage. However, in any case, discs slip relative to each other. This means that in this case the fan does not work. When the temperature increases, the bimetallic platinum begins to shrink to fuse, squeezing the silicone fluid from the tank. The pressure on one of the disks begins to gradually increase, the discs begin to press to each other - the fan begins to rotate.
When the temperature drops, the bimetallic plate is gradually returning to initial positionThe pressure inside the coupling drops, discs are separated, and the fan stops.

The radiator's viscous food is installed on the pump shaft along with the fan. Sometimes the design is mounted on crankshaft shaft - everything depends on specific model car. It should be noted that the fan with the Viscounts - a much more efficient system than the usual impeller installed on the shaft. The Viscouft is triggered as needed, while not cooling the engine without need, for example, in winter.
Most often, the fan with a coupling is installed on cars designed for heavy loads:

Trucks.
Crossovers.
SUV.
Sports, I.T.D.

How to check the operation of the cooling radiator fan

If the car is not exploited for a long time, then the cooling radiator wedge may need to be replaced by oil and verification for faults. Of course, the exit of the Viscounts failure is due to wear or mechanical damage. Define the presence of a malfunction of the Viscounts is quite difficult, but maybe even at home.
One of the most simple ways Checks - Compare the frequency of the clutch circuits with a cold and hot engine. With a cold engine should not be observed outsided sounds, Fan turnover, as a rule, correspond to the norm. When driving the engine can "pop up" foreign noises, and the number of revolutions may not match the norm.
Noise inside the coupling may indicate faulty bearings. In addition, one of the most common malfunctions, the cooling radiator wedge is sealing the seals and leakage of silicone fluid.

Council Pro: Faulty Viscounts are not subject to repair

Almost everyone modern cars Uncovered visuals are established, to repair which, especially in conditions of a homemade garage, is absolutely impossible. But still there are several models, mainly produced by Germany, the design of which allows you to replace bearings and silicone fluid.

When the Bearing of the Viscounts fails, this can be determined by the characteristic SHO from under the hood. If there is a leakage of silicone fluid from the case, the efficiency of the coupling is significantly reduced - the fan begins to rotate slowly, it can even stop completely. The same "symptoms" can be observed at the failure of the disks.

So, if your car installed a collapsible model, you can try to repair yourself:

First you need to remove the fan. As a rule, it is enough to unscrew 3 and 4 bolts. After removing the fan, you can more accurately assess the state of the Viscumpta. If the bearing is damaged, then before removal, it is necessary to drain all the silicone fluid through the hole specifically designed for this. After that, the screwdriver is carefully soaked with a screwdriver, which covers the bearing itself. Next, with the help of the puller, the bearing is removed and installed new. Bearing in the nest is pressed by a special mandrel. At the same time, it is strictly forbidden to beat the bearing with a hammer and in general to put any blows.

If inside the Viscuft is not enough liquid, it can be quite easily determined by a sharp stop of the fan after the engine is muffled. In addition, the engine begins to overheat due to the fall of the fan rotation frequency. Silicone fluid is attached to the coupling using a special syringe for this. However, it is possible to use the usual medical, the largest "caliber" that will be able to find.

As for damage to the discs, it can be accurately determined, only completely disassembled by the Viscuft. Repair discs can not be renovated.

Fully replace the cooling fan uniform. The node that came into disrepair is removed from the engine, unscrew the impeller. Install new detail. When installing, it is necessary to pay attention to the fact that the bolts are tightly tight. Next, the fan is installed in its place. It should be noted that in the overwhelming majority of cases, the Viscuft is much easier and faster than bother with its repair and recovery.

As to Aliexpress to find and order Viscounts at a reasonable price and free shipping

Today is one of the largest and most popular trading platforms in the world. You can buy here in a literal sense, everything that is not prohibited by law, and at the most attractive prices. Auto parts - no exception, almost any details for any car brands are available.

In order to take advantage of all the advantages of the service, it is necessary to go through the registration process. IMPORTANT: All data is filled in Latin:

After that, you can start searching for the desired goods. To find goods with free shipping, mark the checkbox checkbox specified by the arrow:

By selecting the right product, you need to click on the "Add to Cart" button, or "buy now", after which it is possible to calculate in any suitable way presented on the site.

That's all. It remains only to wait for the delivery of goods, which takes from a month to two.

The work of many products is based on the use, sometimes unexpectedly, a variety of properties of substances familiar to us. An example of this can serve as a Viscounts - a special device intended for electoral transmission, depending on external conditions, torque. In such products, the principle of operation is based on the change in the viscosity of the liquid filled into it. It cannot be said that they are applied extremely wide, for example, as MCPP, but also bypass their use would be wrong.

Viscounts - viscous coupling, part of the car transmission, mechanism of transmission and leveling of torque. In contrast to the hydromule and the hydrotransformer in the Viscuft used a different principle of operation. In this device, the torque is transmitted not through the dynamic properties of the fluid flow, but using the viscous properties of the fluid filling inner space Viscounts. It is used as a mechanism for automatic blocking of differential.

HISTORY OF THE INVENTION

The Viscouft was invented in 1917 in the US Melvin North, but did not find applications at that time. In 1964, the Viscounts was first established as a mechanism for automatic blocking of the inter-axis differential by car Interceptor FF English company Jensen. From the mid-60s, the Viscounts have found wide use in self-locking inter-track differentials on passenger cars with permanent drive on all wheels.

Principle of operation of the Viscounts

What is the cooling fan viscous fan? This is a special mechanism that performs the function of selective transmission, which depends on external conditions, torque. The viscous clutch looks like a housing that is fully sealed, with a two-row drives located inside. One of them binds to the slave shaft, the second with the lead. These disks are moving with each other. Each of them has both holes and protrusions, and the distance between the planes of the disks is minimal. The body of the Viscounts inside is filled with a viscous fluid, which is often manufactured on silicone basis. The fluid for the viscous coupling is characterized by specific features that allow it to be effectively used.

This is: an increase in viscosity with an increase in the mixing intensity. High expansion coefficient during heating. When the car moves at a constant speed, the disks of the Viscuft rotate uniformly and the oil between them is not mixed. When the speed of the slave and the driving shaft varies, the speed of rotation of the disks is also varied. As a result, the viscosity of the fluid increases, and it affects the transmission of torque to the slave shaft. When the difference in the rotational speeds of the disks is very large, the oil for the Viscouft becomes so viscous that it is blocked. The liquid goes into a state close to solid.

Viscouft species.

Currently, 2 types of devices are used in cars:

• with a constant volume of dilatant liquid;
• in which the working volume of the substance depends on external conditions.

The first are used in the so-called. self-locking differentials in car transmissions, including for automatic connection full drive.

Scope of the second - engine cooling systems, here they are used to control the fan.

Work details in the transmission.

When moving in normal mode on a normal coating, the angular velocities of the wheels of both axes are the same. The viscous clutch discs rotate with equal speeds, the transmission of the moment from the engine to the slave is minimal. In fact, the car becomes completely front or rear-wheel drive.

When driving on ice, snow, dirt, irregular wheels, the synchronism of rotation of the wheels is broken, the viscosity of the fluid in the device increases, increasing the transmission of the torque on the second axis. Theoretically, such power transmission in some emergency modes can be up to 100%, although, as a rule, even partial connection of the second axis is sufficient to safely overcome the problem area.

Important! It should be understood that the viscous coupling in no way is not a full-fledged inter-axis differential, which ensures the redistribution of the engine torque on both leading axes.

The use of parts is justified on uneven coatings, with ice in the city or humid route. When driving in conditions full off-road The retardation of the response of such self-locking differential is invalid. In addition, permanent loads can lead to fluid overheating in the device, loss of working properties and complete self-blocking, which is fraught with breakdowns of other car systems.

Currently, on vehicles with automatically connected full-wheel drive, the Viscounts are operated in the "sample mode". It is characterized by a constant transmission from 5% to 15% engine power to the slave axis, which significantly reduces the time of the reaction of the mechanism.

Where are the Viscounts apply?

Actually basic applications are only two, but now only one thing remains:

• Applied to cool the engine. The viscous fan was fixed on the rod. It was driven from the crankshaft of the car by belt transmission. The faster the engine rotates, the more thick liquid and the connection with the fan became tougher. If the revisions fell, it did not occur such strong mixing, which means there were slipping, that is, the fan turned, not so much cooled the radiator. Such a system is effective for a cold (winter) period when the engine is not strongly heated, and it is also cooled. Now the use of such systems on new cars has not yet to meet, electron fans (with fluid sensors) are replaced, which are powered by electricity and are not related to crankshaft Engine.

• Automatic connection of the full drive. It is in this direction that the Viscounts remained very much in demand. Almost 70 - 80% of crossovers or parcktails, such systems are now used. True, they are gradually starting to force out completely electromechanical options, but for now they are more expensive and not so practical.

On the one hand of the Viscounts, this is a very simple, cheap, practical and universal mechanical device, with another there are quite a few minuses.

DIY repair of Viscouft

If you notice the engine overheating, do not rush to make the replacement of the Viscounts. You may be able to repair the detail's broken item on your own. The most common cause of a malfunction is silicone leak from the base of the part. To pour a new liquid, you need: to remove the viscous coupling from the water nanos, then disassemble it. On the device's disk itself, there is a plate with a spring, under which there is a hole for silicone fluid.

You need to remove the pin with maximum caution, and then pour lubricant with a syringe. Consider, during such a repair, the detail is put horizontally. The syringe is enough to score fifteen milliliters of oily liquid. Do not rush to pour silicone in inside. Wait a few minutes, not removing the syringe from the hole so that the liquid will have a deeply check in the Viscuft. Wipe the surface of the device from the excess fluid if necessary. Put the pin to the place and then install the item.

If you are poorly dealt in cars and do not know the principle of operation of certain parts, it is better not to start repairing yourself. The point here is not in the possible breakdown of parts vehicleand in difficulty collect everything back.

Also frequent cause breakdowns Viscounts are bearings. Sign of such a malfunction is one single: various kinds of noise in the field of cooling radiator. To repair the device, it first needs to be removed. To do this, unscrew three bolts that fasten the item. After that, the Viscuft is easy to remove from the motor compartment. After feeding the device, you can proceed to replacing the bearing. Provide them only when disassembled the node and merged the oil fluid. Use a special tool for removing the bearing - puller. If you use undergraduate tools, you can damage completely node. By installing a new bearing, you can start installing the device.

Do not forget to pour a new silicone fluid that the viscous coupling has merged before repairing. When you notice the "wrong behavior" of the coupling, you do not need to immediately change the entire item, because it can often be repaired. Special skills and skills for this case will not need. The only difficulty that may occur is the search for the puller to extract the old bearing. The tool is sold not in every automotive store, which makes it difficult to repair the Viscounts. If you have visited all the auto shops you know, and did not find the puller, ask friends drivers. The rest of the items find it unemployment.

Features of repair Viscounts

Not all such devices have a hole for pouring the oily liquid. If you are "novice", do not attempt to repair the device yourself. Experienced masters make holes independently. Of course, you can also try to drill holes at your own risk. Do not apply gross physical strength when manipulating disk. If aluminum on the currency is imagined, the Viscuft will not be repaired - only full replacement Devices.

How does the cooling fan (W) work?

While the engine does not warm, the thermostat directs the flow of coolant for a small circle. In this mode, the substance in the Viscounts is squeezed with a rotating disk to a backup capacity. There is no gearing between the disk and the housing, the fan does not rotate.

The flow of coolant into the radiator causes the deformation of the bimetallic plate, the triggering of the valves and the accumulation of the liquid of the viscous clutch is not in the backup capacity, but in the space between the disk and the case. Due to the viscosity, the unit is blocked, which transmits power from the shaft. The fan comes in rotation, directing the air flow to the radiator, providing a decrease in the temperature of the coolant.

When cooled it up to the level of the threshold of the temperature-dependent node, paths for overflow of a liquid are opened, a viscous friction force between the disk and the body decreases, the fan stops.

Viscounts check.

Any suspicions of emergency work details require immediate check, since its malfunction can lead to serious breakdowns of the main systems.

How to check in transmissions?

The most accurate results gives checking removed from dispensing box Viscounts.

For this, enough:

• Remove the item;
• Turn the differential gear with a key with a dynamometer (or measure the force with a spring dynamometer).

The effort should not exceed the limits set by the manufacturer (you can find in technical writings on the device and reference books).

You can check the item and without removing it. This follows:

• post the wheel of the slave axis;
• try to turn it out by measuring with a dynamometer;
• moment Calculate on the well-known wheel diameter

If the resulting value does not exceed the limits specified by the manufacturer - the part is working. If the wheel could not be checked at all - the device must be urgently changed.

Video manual.

How to check the Viscuft in?

The test of the viscous clutch is not difficult:

• Start the engine "on the cold";
• After 30-60, the fan noise will decrease - it will switch to idle mode (at this point it can be stopped by any obstacle, for example, a rolled newspaper, but it does not recommend this safety);
• After some time, when driving the engine (monitored by temperature sensor), the viscous clutch will increase the speed of the aggregate;
• In this case, there must be a unambiguous reaction to an increase in engine speed - the engine rotates faster - fan rotates faster.

You can check the device in motion (more precisely, in the parking lot among the day). With increasing temperature on idling - Unambiguously we can talk about problems with viscous clutch.

Using the wicked for the wheels of one axis.

Another use of the coupling is possible - for the wheels of one axis. With this application, the device is installed between the axial differential and semi-axis. In this case, when passing the turns or slip of one of the wheels, the device contributes to the redistribution of the moment between them, ensuring the safe execution of the maneuver or the passage of the problem area.

There are decisions in which a pair of details are put on the wheels of one axis. This design allows you to refuse from axial (inter-track) differential. At the same time, the use of a pair of Vicility allows you to provide all modes - both differential rotation and locking wheels of the axis.

Pros and cons of the wicious drive.

Like any device, vz in all-wheel drive cars Have merits and disadvantages.

Advantages:

• Automatic connection of a full drive or mutual blocking of axis wheels, which significantly increases the permeability and safety of motion on complex coatings;
• Simplicity of technical solution and, accordingly, its cheapness and reliability - manufacturers, most often perform devices maintained, counting on the service life equal to the life of the car.

In practice, the mileage of 90-100 thousand km (in severe conditions and less) becomes the limit due to the fluid loss of its properties and faults in other car systems. With this mileage, it is recommended to replace the device.

Disadvantages:

• The delay and nonlinearity of the operation do not allow absolute control over the full drive;
• In most cases, on vehicles equipped with vessels, manual inclusion / shutdown of the second leading axis is not provided;
• Limited dimensions make limit on the transmission of torque, as well as the possibility of long-term operation in a loaded state (overheating and failure is possible);
• Joint work vz and electronic systems Type ABS, ESP and similar difficult, as they solve opposite tasks.

Each car owner should thoroughly know the design of his car. Perhaps most people only abstractly understand what the Vussft is, and the ways to repair it. This tool is greater importance for the car, so it is important to understand its technology.

Principle of operation of the device

It was invented in the United States in 1917 by an engineer Melvin North. This product did not immediately find their application, so for a long time was not recognized. In 1964, the Viscuft was installed in the Interceptor FF car, where it served as an automatic blocker for differential. Only in 1965 this mechanism took his place.

Viscounts is a device that is responsible for rotating a special fan, which cools the system due to special fluid. It has the form of a circular mechanism made of silicone base and filled with a lubricant. The Viscuft provides smooth fan adjustment.

Flat discs are located inside the body. Some of them are connected to the leading shaft, and others with the slave. There are various protrusions and holes on their surface. Features of the design have these items in close proximity to each other. Silicone fluid, located inside, has the property to thicken with strong stirring. It also expands when heated, so it creates a large pressure on the discs when the engine is running and compresses them together.

Features of the mechanism

At first glance, the principle of operation Viskorsfit fan cooling seems difficult, but it is not. Movable is driven into rotation and transfers its energy clutch. From this, its silicone base becomes softer and viscous. The coupling begins to blocked, which is due to the rotation of the second disk with the fan.

In almost every engine there is a Viscounts. This is due to the importance of its functions and quality of the device, because it is enough high level. In the Viscounts, the safety mechanism is perfectly implemented: when a person on his own carelessness shoves his hand to a moving element, he will stop to prevent injury.

Checking the cooling fan

It is not always possible to regularly use the car, so it turns out to be in idle state. Viscouft at this time requires checking its performance. It will help prevent breakdown from wear.

It is not easy in regular conditions, but there are methods how to check the fan viscous coupling. To inspect the mechanism, you need to check the condition of the turnover of the product when the heated and cold engine is enabled. With a cooled motor, no extraneous sounds should not occur, and the turns must match the norm. The hot engine can often provoke various noises and failures in the frequency of revolutions.

Such problems may arise due to faults in bearings or undime replacement Oil. Also, the sealing glands and the leakage of silicone fluid can cause breakage.

Solving the problem with your own hands

If defects were found in the work, the viscous fees should not be conducted. These problems can often be solved with their own hands. One of the most frequent problemsarising in this device is the leakage of silicone fluid. To fill the lack, you need to perform the following actions:

1. Disassemble VcKamuft by removing it from the water pump.
2. It is necessary to look at the product disk. On its surface there is a special plate with a spring under which there is a silicone hole. It is necessary to remove the pin with extreme caution and pour into the lubricant with a special syringe. During this process, the part itself should be put in a horizontal position.
3. It will be enough to fill in a syringe of 15 milliliters of fluid.
4. It is necessary to wait a few minutes until the substance checks the viscous coupling inside without removing the syringe.
5. After checking the correctness of the procedure performed and there is no silicone surplus, the item can be installed back.

Those who do not consider themselves experienced motorist, it is better not to engage in such works, because it can cause complete breakdown of the device. As a rule, the greatest difficulty consists in the reverse assembly of all elements.

Other problems

Often the bearings can cause the failure of the Union. This is evidenced by the emergence of unusual noise in the cooling zone. But it can also be repaired independently:

1. To fix the product, it needs to be removed from the main engine design. For this, 3 bolts are unscrewed on which bearings are attached.
2. Replacing these elements should be carried out only after it was merged oil fluid And disassembled a node. To simplify the process, you can use a special tool - a removal. It is not necessary to use fir-handed appliances, as they can finally damage the details.
3. After installing the bearing can be carried out in the mechanisms of the motor. Before that, you need to pour fresh silicone, which was merged before replacing parts.

Note: Not always the wrong behavior of parts requires their ambulance. Often you can do and simple repairwhich does not require special skills.

A frequent problem when checking the Viscuft or replacing bearing is to search for a suitable tool. Such a removator is not always easy to find in the car shop, so the repair can be difficult.

Features of repair work

As some motorists could notice, not always on the Viscounts there is a hole for filling the silicone fluid. In this case, it is done independently, but you should not make it novice to not harm the product. It is better to refer to the masters that make a neat drilling.

Repair of the Viskors Fan should be carried out without a thoughts underworse. The main material of the device is aluminum, which is easy enough to bend and finally deal with the Viscuft.

The work of the car depends on many mechanisms that should work as a whole. At the failure of at least one element, the serviceability of the entire vehicle is disturbed. Viscounts are necessary for normal operation of the cooling fan. This depends on the safety of the trip, so you need to monitor its performance.

Repair of the cooling fan uniform should be carried out only by specialists. Of course, you can do it yourself, but any error can derive a device. You need to take care of the service work in advance.

Every motorist was interested in the question: What is Viscounts? Let's try to answer it. Viscomer - this is a mechanism for transmission and leveling of torque in the transmission of a Renault car, Volkswagen, etc. Other its name is a viscous coupling. The principle of operation in it is completely different than in a hydrotransformer or hydromeflu. The torque is transmitted due to the viscous properties of the fluid, which fills the inner cavity of the Viscounts. It is used to automatically lock differential.

History

In the United States of America in 1917, Melvin Severn invented the Viscounts. But its invention has not been applied. On the Interceptor FF car of the English company Jensen, it was applied as the mechanism of automatic blocking of the mid-scene differential in 1964. On vehicles with constant full-wheel drive, Viscounts took its niche since 1965.

Viscounts: device, principle of operation

Inside the sealed housing there are several round flat discs. A certain number of drives are connected to the leading shaft, and some number of slave disks with a slave shaft. Their surface has holes and protrusions. All discs are mounted so that rotating, they are located at a very small distance from each other. Inside the coupling case is a dilatant liquid based on silicone, which is thicken with strong stirring. Also, it has a large expansion coefficient when it is heated. With stirring, pressure appears on the discs, and they pressed to each other by expanding this fluid.

How the Viscounts are arranged - video

If the movements of the shafts are uniform, the discs rotate at the same speed. When the fluid is not mixed, there is no pressure on the discs. With a different rotation of one shaft relative to the other, the discs begin to rotate relative to each other. The liquid is mixed, the viscosity is growing, the angular velocities of the disks are trying to level due to friction force. And with a huge speed difference, this liquid has a solid properties. At this moment, the viscous food is blocked, its maximum acquires a torque from the leading shaft to the slave.

Disadvantages and advantages

The viscosity of the fluid depends on the speed of its mixing. To guess the braking coefficient of disks is impossible, because there is no linear dependence of the properties. Therefore, such differentials are not high in such differentials. Viscufts without free six-time differentials are not used due to a large design and low efficiency. Since the coefficient useful action Viscounts are directly proportional to the volume of fluid and the diameter of the disks, then such a device increases the size of the leading bridges, which leads to a decrease in clearance.

The advantage is the simplicity of design. The body of the Viscounts can withstand the pressure of fifteen atmospheres. It does not require attention at the time of the whole life. If she failed, it simply change it.

Where are the Viscounts apply?

On Lancia Thema and Lancia Dedra 2000 Turbo Lancia Dedra 2000, the Viscuft was used as a mechanism for automatic blocking of a free six-grade differential. But the main use is to use on cars increased passibility as an inter-seed self-locking differential. For example, on jeeps and Range Rover HSE Viscounts was used as a self-locking differential. It can also perform the function of the interlocking mechanism, which works with a gear free differential.

Video

Synchronize the torque between the bridges can be simple and inexpensive, this applying the Viscounts. Under normal conditions, the difference between the torque moments, the work of the Viscouft is enough, so as not to allow to slip the front wheels relative to the rear wheels. So, when moving along the dirt road, one pair of wheels makes a piece of obstacle, the second pair rides directly, and the viscous clutch at that moment aligns their speeds.

Video

But, as it is a problematic to apply the Viscuft with an anti-blocking system of wheels, almost all world autocontracers stop using them and install forced Haldex forced clutches on their cars.

In modern passenger cars in the engine cooling system, electrical drives of the radiator fan are used. On Russian roads, you can meet machines equipped with an ussociate, as a means of actuator of the radiator cooling fan.

Such couplings due to constructive featurescan only be installed on cars with a longitudinal engine installation, that is, with rear wheel drive. Most cars now have front-wheel drive, Therefore, the Viscuft in the engine cooling system can not be seen often.

Not every one hundred there are specialists who know how to check the cooling fan uniform for performance, execute it maintenance and repair.

Operation Principle Viskors Fan Cooling

This device is sometimes referred to as the "viscous coupling". Its rotor using a belt transmission is connected to the crankshaft pulley of the engine. On some cars it is installed directly on the shaft of the crankshaft or camshaft.

The design of the Viscouft has two disks located close to each other, but mechanically unnecessary. They are located in a closed cavity. One of the disks is mechanically connected to the drive rotor and crankshaft (camshaft). Another disk leads to rotation of the impeller of the fan cooling radiator. Since the disks are mechanically not connected, then theoretically, the engine rotation is not transmitted to the fan, it will be fixed.

Video - What is the viscommosphea and its principle of work:

When heated viscosity coupling change geometrical dimensions Bimetallic plate that is installed in it. It opens the channel for admission to the cavity, where there are disks, viscous gels or oils, which, as the cavity fills, viscobles binds the discs. For greater engagement on the disks there are additional edges or ridges that increase the degree of engagement. Thus, the "viscous" gearing between the disks is provided, respectively, the engine rotational moment is transmitted to the radiator fan, it is cooling.

Video - How Wussoft Cooling Fan Works:

As cool, the gel is pumped out of the chamber under the action centrifugal forces, and viscous connection stops.

Typical design of the viscoseuft shown in the figure, it makes it easier to understand the principle of its operation:

1 - spring;

2 - bimetallic plate;

3.4 - intake channels B and A;

5 - camera;

6.7 - return channels;

8 - rear spring;

9 - front tank;

10,16 - Rotors;

11 - case;

12 - Rotor shaft;

13 - Bearing hull;

14 - rear reservoir;

15 - rear plate;

17 - front plate;

18 - cover.

In general, the design is quite complicated, therefore the cost of the new Viscumpta is high.

In some cases, when a viscous clutch malfunction, which does not allow it to be recovered, in the absence of analogs, car owners are forced to convert the car to the system with an electric fan.

The main causes of malfunction

If you produce timely regulatory service Viscounts, its resource is at least 200,000 mileage kilometers. Given that the majority of cars on which such drives are installed, have a solid mileage, the owners of these cars faced the problems of the Viscouft more than once.

To the main reasons for malfunctions can be attributed:

• natural wear;
• change in the parameters of bimetallic plates;
• bearing wear;
• batings of the impeller of the fans (partial destruction of the impeller);
• exhausting gel, late refueling, change of gel structure;
• mechanical damage.

Also, a premature refusal of work can be sought against the clogging zone of the radiator cells, contamination of the coupling structure.

Signs of malfunction

The main sign of the malfunction of the Viscounts - engine overheating. This happens, mainly if the gel is either, or does not work in time a bimetallic plate. In this case, the fan is not starting to rotate or rotates on small circulation, without providing normal cooling Radiator.

Reverse malfunction when the fan begins to rotate impact engineIt often occurs when the physical parameters of the gel, the failure of numerous units of the Viscounts, frozen lubrication.

Advantages and disadvantages

The cooling system malfunction is a critical car malfunction at which it is impossible to continue further independent movement. Therefore, the main consumer characteristics of the Viscounts - reliability. With this position, it is higher than in the case of the electric drive of the radiator fan.

Many car owners are familiar to the problem when after the winter season has to repair the electric drives of the radiator fans, electronic circuit Controlling the engine cooling system. In the system of viscous coupling, electricians and electronics are not, it is a big plus.

Another advantage of the Viscounts is a high power it can provide a fan on the shaft. Theoretically, this power can be equal to the entire power on the engine shaft internal combustion, that is, a few kilowatt. Electric motors of radiator fans passenger cars have the power of about a few dozen watts. Therefore, in a powerful agricultural, construction, military equipment Until now, the Viscouft has not yet abandoned.

Disadvantages of Viscounts:

• the complexity of technical execution, the difficulty of repair, is easier and cheaper to replace it with an aggregate (entirely);
• has a large mass, has a mechanical load on the shaft;
• the temperature control of its inclusion does not have sufficient accuracy;
• increased noise by high revolutions engine;
• when conducting regulations It is necessary to make a refueling (refueling) of the viscous food with gel or butter of certain viscosity, such specifications In reference books find it difficult;
• additional engine power selection.

These and other disadvantages have practically displaced the viscous coupling from the cooling systems of the internal combustion of passenger cars.

Restoring engine cooling system

In case of refusal to work, the Viscounts should first make it refueling with oil or gel. There is no accurate recommendations on this score, usually you have to experiment.

You can try to find narrow specialists, but it's easier and cheaper to find b / e-sins on disassembly. If the search for a serviceable viscous coupling is unsuccessful, you can think about replacing the cooling system to the usual, with an electrically driven.

Video - Replacement Viscounts on an electric fan on BMW:

Can be installed electrical system Cooling on a simplified scenario. For this, you will need the following components:

• cooling fan with an electric drive that can be adapted to your radiator;
• wire set with a cross section of at least 6 sq.m.;
• fuse at 40 amp;
• automotive relay on current of at least 30 amps;
• thermalleere, you can Zhigulevskoe on the response temperature of 87 degrees Celsius.

The thermorel can be installed on the radiator or on the metal surface near the thermostat by gluing. Next need to collect electrical circuit The inclusion of the fan is similar to VAZ. Such. simple scheme Without refusal, there may be five seasons.