CVT has a large number of users in China, and its working principle is very simple, which can be said to be the simplest structure and principle among various automatic gearboxes.
The CVT gearbox used in passenger car field is reformed, and the speed change is realized by changing the contact radius between two groups (four groups) of bevel gears and steel belt. Among them, these two groups (four wheels), each group is two trapezoidal cone wheels, and a small part of the trapezoidal section is on both sides. Automobile gearbox has experienced the evolution from manual transmission to automatic transmission, and AT gearbox and dual clutch gearbox are more common in automatic transmission vehicles. CVT gearbox is also called continuously variable gearbox. Its appearance is mainly to solve the problems of relatively high cost and low power efficiency of AT gearbox. In order to reduce the manufacturing cost of gearbox, reduce the price of automobile market and occupy the market of low-end models conveniently and quickly, Japanese cars make every effort to build and use CVT gearbox.
There are many kinds of CVT gearboxes. The mainstream models in the market generally adopt steel wheel structure, and the transmission structure is the same as that of ordinary gearbox. Some CVT uses hydraulic torque converter, and some CVT also uses wet multi-disc clutch, so the power loss will be greater during the first transmission, but don't worry about wear, the shift will be smoother and the loss will be smaller. Therefore, few vehicles equipped with CVT are still running. The disadvantage is that the torque is low, generally around 180-250 N/m, and the CVT with the largest power can only bear 450n/m due to the limited clamping force/static friction between the steel belt and the cone. With low temperature protection, the car can't be cold started in cold environment, and it needs a thermal gearbox.
Because when the engine water temperature is low, the oil temperature of the engine gearbox is also low, which will cause abnormal wear and short life, and because the steel belt is long, you can't help but maintain it. After years of friction, the physical structure of the cone will change and wear is inevitable. Special gearbox oil needs to be replaced, and the requirements for gearbox oil are strict. Because CVT needs special transmission oil, it is inconvenient to maintain. Once it is damaged, it can only be replaced, because the common fault of CVT gearbox is that the steel belt breaks, resulting in slipping and abnormal sound. It can't be repaired, so we can only replace it with a new one.
Therefore, it is necessary to treat the durability of CVT rationally. The life of CVT gearbox is generally not as long as AT, and the failure rate is higher than AT.
This is a fact. It still takes some luck to buy a CVT gearbox.