Transmission CVT - what is it? Car transmission - CVT

Just having a car is not enough, it's also important to understand what's in it and how it works. Naturally, no one requires a thorough knowledge of the principles of the internal combustion engine from an ordinary driver, but at least simple things need to be understood in order to repair the machine if necessary. Unfortunately, there are failures. And now we are talking about one important element. Transmission CVT - what is it? It is on this topic that we'll talk further.

Transmission

It is with these principles that we should begin. First of all, you need to understand what this device represents as a whole. And then think about how the CVT gearbox is arranged, what it is, and so on.

So, the transmission is an obligatory element of the car. The fact is that without it all the work of a complex internal combustion engine will go wrong. The operation of the transmission is to transmit the torque from the engine to the wheels. Actually, this leads the car into motion. So, as you can see, the importance of it is rather difficult to overestimate.

In addition, there are other functions, for example, changing the tractive effort, speed, as well as the general direction of motion. The transmission consists of a whole galaxy of various parts. In this case, we are interested only in the gearbox. But it will be discussed a little lower.

In addition, you also need to know that cars usually use electromechanical, and sometimes just a mechanical transmission. At least, this is the situation for today.

Gearbox - what is it

What you need to understand is that this system is typical only for cars with ICE. In other cases, for example, for electric vehicles, there will be no levers. Simply because there is no such need.

The operation of the gearbox as such is as follows: the engine that is used in cars has a very wide range of torque. The wheels, in turn, can not rotate at the same speed. Using the transmission allows you to level the difference in speed. KP also helps the driver to control the speed of rotation, accelerating and slowing down at the right time.

From what still needs to be said: to date, mechanical manual transmissions, automatic, and variators are used. It is for them to dwell in more detail.

Manual Transmission

It is not necessary to stay very long, but some things should be clarified. For example, the principle of work. So, it consists in a complex mechanism of shafts and gears. It is they who are controlled by the driver, shifting the transmission lever, simply adjusting the mechanism for the desired mode of operation. All combinations of the mechanism differ from each other in the gear ratio, which will depend on the speed that the whole car collects.

In general, almost all cars that can be seen in the city, if installed and mechanical, rather than an automatic transmission CVT, then only three-way. This means that there will be five or six operating modes. That is, four, and possibly five speeds for the ride ahead, as well as a rear speed to change the direction of motion. This is how the 5-speed gearbox is created.

Sometimes there are specimens with a four-way box, and this means having a sixth or even a seventh gear.

This can be called a certain excess for the city machine. If we talk about more complex designs, then in cars they are not used at all.

Automatic transmission

Technically, any gearbox that is able to work independently, without the participation of the driver, that is, reaching the required speed, simply changing the combination of shafts, is considered automatic. But in practice, this is usually the name only of planetary hydromechanical systems. They are most common, and speech almost always comes about them. Therefore, it is not necessary to consider other options.

Is that worth mentioning about electropneumatic and electromechanical devices. The fact is that everything works on electronics, that is, a certain algorithm of actions is "sewn" into the KP itself.

Nevertheless, the driver is not completely excluded from the process - this is necessary to ensure safety. So, a person at the wheel can choose the mode of operation of his car. Actually, it depends on this aspect, how fast the gears change and what is the speed limit.

To regulate such parts, the usual lever is most often used. True, his appointment has changed over time, but many drivers are so simply accustomed. However, there are also such models of machines where buttons are used. On modern cars in general, you can find a full-fledged numeric keypad, which, in fact, controls the system.

Variable speed drive

Transmission, transmission is all, of course, very important information. But now we need to approach the main topic of the conversation. That is to the Variable Transmission. Actually, this will concentrate all attention.

CVT, or Continuously Variable Transmission, - this is the meaning of this abbreviation. The peculiarity of this gearbox is that it is able to smoothly change the speed range. Thus, you can avoid sharp jerks, which are typical for mechanical, and even soft tapping - for automatic transmission.

Advantages of such a system is quite a lot. But it is necessary to note the main of them - the ability to use the engine's twisting speed with the maximum possible efficiency. Everything happens thanks to the well-coordinated work of the engine elements. In addition, fuel economy when using such a device is quite high, and it's a pleasure to drive in this way.

Today they are used exclusively for cars. The fact is that technically they are rather complicated, therefore to produce them sufficiently large and powerful for the same tractors or tanks - a difficult task. In addition, their main goal is to facilitate the existence of ordinary people, and they, as you know, drive mainly on sedans and hatchbacks.

The device and operation of the variator

Transmission CVT - what is it? To understand, you need to first understand its device. In general, this is a rather complex mechanism, as mentioned earlier. But the general structure can be explained.

So, the main place is occupied by the device, which provides simultaneous transmission of revolutions from the engine and its disconnection with the box. Used to work in a neutral position. The variator as such is used for driving at any speed. The reverse mechanism is controlled by a separate mechanism - the fact is that the CVT is simply not capable of providing movement in this direction. Therefore, we have to borrow workings from automatic transmissions.

Devices that are used can be different. This is now the first in the list, that is, the transfer of torque. For example, the most common is a torque converter. Further, there is still centrifugal and electromagnetic coupling, and in addition - multi-disk "wet".

Variants of variator

Such a tautology is quite appropriate. The fact is that to create the very mechanism of CVT can use slightly different parts from each other, which affect the work.

For example, the cheapest and most common are the V-belt variators. It uses an ordinary belt drive, formed with the help of two conical disks. The movement of the latter affects the overall diameter and is controlled by a hydraulic mechanism.

Rubber belts have long since sunk into oblivion, mainly because of their fragility. With a working resource of only fifty thousand kilometers and a rather poor flexibility, there is nothing surprising in this. They were replaced with metal belts made of several steel strips. All the problems of past options have been resolved.

There is one more possible method of working - a metal chain. Flexibility here exceeds all expectations. For the transfer of momentum, all the same high-grade and very strong steel cones are used. All this is necessary to increase the service life. Since this is quite a modern development, it is not surprising that it replaces all analogues from the market. The efficiency is the greatest, and the losses inevitable in the transmission of torque are minimized.

CVT (gearbox). Minuses

Like any other device, this is not immune to shortcomings. They simply compensate for the benefit of bringing such a mechanism.

Firstly, if you transfer to a car with a similar KP instead of the usual one, you will feel some discomfort for a long time. The fact is that the revolutions can fluctuate in a wide range. Especially often this happens when the car accelerates. But such a disadvantage is compensated by the fact that the work itself is more smooth. As it was said before, there are no jerks and other "joys of life" on bad roads.

You can also give a practical example of one of the famous automobile manufacturers. For example, CVT transmission Nissan. One of the models, "Altima" 2013 release, is equipped with just such a system. So, the drivers complain about a fairly palpable lack of sensitivity. True, not all of this is noticed, which is worth mentioning separately. Also, the head of the company specified that such devices are a good alternative to automation, moreover, in addition to low fuel consumption and minimized emissions.

It is worth considering and the fact that not every CVT is able to cope with towing. In addition, the general unreliability of the old models has strongly impaired the reputation of the system as a whole. But to date, such problems are mostly solved. At least in terms of longevity.

Acquisition of

Another interesting question is the price of the gearbox. The point here is that the variator must be purchased in its entirety - immediately together with the transmission. Otherwise, there will be no sense from such a purchase. And here the very difficulties arise, because the price of the matter is very, very high. Transmission is an important part of the car, and so you can not save on it.

Only the purchase itself can result in the amount of more than 200 thousand rubles. Often even much more. And this is without taking into account the installation, the passing of the inspection, and so on.

Nevertheless, it is possible to find such details. There are two main ways for this. The first is to contact a service center or a branch of the manufacturer in your city (they can advise a place to buy parts for their car), a supermarket of spare parts, or try to do everything yourself. That is, buy with hands. However, in the latter case, no one can guarantee you the safety of your investments.

As for the installation, it is much better if it is made by specialists. Not having enough experience in handling such mechanisms, it's easy to screw up. And given the amount spent, this is not entirely reasonable.

Repair of automatic transmission

The next important point of the plan is to learn how to take care of your own "swallow". In fact, call the variator an automatic box is not entirely correct, because the gear itself is simply not there. But in general this is not so important.

The most vulnerable part of the design is a belt. Actually, most often the repair of the automatic transmission is in its replacement. The problem here is that the now popular steel chain is quite capable of damaging even the cone-holders, despite their strength. But this can lead to very serious consequences.

You also need to monitor the speed sensor. The pre-installed is not particularly reliable, it can often fail. For example, when a belt breaks, it simply freezes, although it turns the transmission into an emergency mode. The latter, however, is far from omnipotent, and still can not save from the consequences. By the way, oil is replaced in such boxes only on specialized service stations. And there are very few qualified mechanics who know the service of a continuously variable variator. Therefore, even such a simple procedure, like oil change, becomes very problematic for the car owner.

Conclusion

Actually, that's all you need to know about the variator. So now you do not have to ask such a difficult question: "CVT transmission - what is it?" Note that this device is whimsical. It is this word that can be characterized. Uncertainty on uneven roads, especially on unpaved roads, some problems with a guarantee and general reliability - all this does not inspire much confidence. Therefore, it is unlikely that it will cope with competition in the Russian market.

Nevertheless, the transmission CVT transmission (variator) is quite suitable for use. In some ways, it even surpasses its counterparts. While this gearbox has not yet been brought to absolute perfection, it is still worthy of attention.

So, we have found out the device of such transmission, as a stepless variator.