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, what is the Vussft

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 on direct purpose - as an inter-axis differential blocker into an English car Interceptor FF. Since then, the Viscounts have been widely used in self-locking differentials on passenger cars with a constant total drive of 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 the angular velocities of moving inside the viscous food 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 2-hour coefficient 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 deficiencies of the Viscuft is a relatively long time of operation - the unit allows slipping of the wheels before they are locked, and the engine will move 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 viscous foods 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 unfair and needs to be replaced.

Control of free stroke is checked as follows:

A lift and one helper are needed.

• The car is promoted to a height of about 1 meter from the floor.
• Together with the assistant, the rear wheels are simultaneously starting to turn forward. The front wheels should remain fixed.
• Next, along with the assistant, turn the rear wheels towards the rear. 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 there is a vacuum to trigger the blocking system, you need to start the engine for about 30-40 seconds at idle, after which the engine can be drown.

• One person 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 back speed, the clutch squeezes it until it stops.
• 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 its original position, the 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 the crankshaft shaft - everything depends on the specific car model. 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.
• SUVs.
• 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 easiest ways to check is to compare the frequency of the clutch speed with a cold and hot engine. With a cold engine, no extraneous sounds should be observed, the fan turns, 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 all modern cars are established unintellular viscous coupling, to repair which, especially in the 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. Set a new item. 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

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