Many people worry that CVT is not durable. For example, some people say that CVT is prone to various protections when it is opened fiercely. The owner who bought CVT said that it was broken after driving for tens of thousands of kilometers, and the steel belt was directly broken. I am afraid that one day I will be recruited!
To clarify the durability of CVT, we must first start with the types of CVT, that's right! CVT is also classified. How to distinguish CVT types? It all started with the drive belt. When it comes to drive belts, Bosch must be mentioned first!
Monopoly is cool for a while?
The most common transmission belt of CVT is belt drive type (known as push type in the industry), which looks very complicated. In fact, the pusher is fixed from both sides with steel belts.
This steel belt with drive is Dutch (Hub? A van? Doorne), the patent belongs to the company founded by the inventor (VDT), and the company holding the patent of belt drive was acquired by Bosch in 1995. Although the gearbox company was sold to Bosch, Dutch DAF company was the first to use this CVT gearbox. Bosch has been improving this technology since it acquired VDT.
Bosch not only owns the patent of belt drive, but also has a wide selection of products. Bosch's drive has a regularity, with large transmitted torque, large number of steel belts and wide pusher.
Bosch's current drive belt can withstand up to 400N? M torque, so many supercharged engines dare to be equipped with CVT, Nissan Teana, and the 2.0T engine equipped with QX50 in finidi, England, with a maximum torque of 380N? M, even so, matches CVT. Bosch's drive belt requires high steel belts on both sides. Once the steel belt breaks, it will jump into the street! Often said that CVT has a flat tire, that is, the steel belt is broken.
Of course, the explosion of CVT is an example, and neither Toyota nor Honda's CVT has ever heard of it. Another problem with belt drive is slippage. Toyota has an idea. It adds a gear (1 gear) to the CVT gearbox, which is directly driven by the gear when starting at low speed, and switches to the CVT gearbox once it reaches the middle and high speed, so that the steel belt avoids the working condition of starting at high torque.
Moreover, because 1 gear itself reduces the task of CVT steel belt, the diameter of steel belt does not need to be particularly large, and the taper of steel belt can also be reduced, so there is no need for pulley to exert great force to squeeze steel belt, so the transmission efficiency is improved! What I want to say here is that belt drive is the most widely used CVT at present, and some cars have had problems, but it is not the structural problem of belt drive itself, but the performance of steel belt is not up to standard, and most CVT quality is up to standard!
Always exclusive, always cool?
Schaeffler holds the patent of chain drive belt. According to the data published by Schaeffler, 6.5438+0.2 million sets of chain drive belts have been produced, which looks impressive, but it is insignificant compared with the type of belt drive!
The chain drive belt looks very complicated, but it is actually similar to the chain of a bicycle, except that this chain is composed of more than 1000 flat chain.
Schaeffler's chain drive belt is not only different from Bosch's belt drive in structure, but also different in working characteristics. It contacts the pulley through the locking pin. The advantage is that it can exert great extrusion force on the lock pin, so that the CVT gearbox will not slip and the chain itself is very strong. For example, many four-wheel drive transfer gears are chain drives, and many engines also use timing chains, so don't worry about its durability and strength. But the winding radius of chain is large, and the transmission ratio is not as high as that of belt drive.
Chain CVT costs more. Out of curiosity, the professor went online to check, and the original price of the chain was about 7000 yuan. There are very few cars using chain CVT, so Audi will go there, because the previous A4 and A6 were discontinued, and now Subaru still insists on using this CVT. It seems that few Subaru owners have responded that the gearbox is not working. In addition, GM has also developed a chain continuously variable transmission, including Angola GX? 1.3T？ All CVT models of GM are chain drive belts.
Professor summary?
Worrying about the reliability of CVT is completely worrying! First of all, CVT is not a new technology, its history can be traced back to more than 70 years ago, and now CVT technology is very mature, except taming high-powered cars, other aspects can fully meet household needs.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.