CVT [ AUTOMATIC TRANSMISSION -INFINITIVE GEAR RATIOS]

 There are various configuration of CVT  one is below

History of the CVT

Leonardo DaVinci sketched the first CVT in 1490. Dutch automaker DAF first started using CVTs in their cars in the late 1950s; however technology limitations made CVTs unsuitable for engines with more than around 100 horsepower. In the late 80s and early 90s, Subaru offered a CVT in their Justy mini-car, while Honda used one in the high-mileage Honda Civic HX of the late 90s.
Improved CVTs capable of handling more powerful engines were developed in the late 90s and2000s, and CVTs can now be found in cars from Nissan, Audi, Honda, Ford, GM, and other automakers.

COMPONENTS OF CVT

1.PRIMARY PULLEY
2.SECONDARY PULLEY
3. BELT

PRIMARY PULLEY

The main components of the primary pulley are fixed and movable sheaves, a set of two flyweights, and a compression spring. As the engine speed increases, the flyweights tend to swing open and push the movable sheave inward toward the fixed sheave. However, this movement is not possible until the force created by the flyweights is able to overcome the force caused by the primary spring. Once this is occurs, the flyweights must also overcome the resisting force caused by friction between the belt and
the sheaves as well as the spring forces in both the primary and secondary pulleys.

SECONDARY PULLEY 

The secondary pulley includes fixed and moveable sheaves and a spring loaded in compression. As the primary begins to shift, its two sheaves move closer together. This,in turn, narrows the width of the v-slot driving the belt to a larger diameter. The normal force caused by the wedging of the belt between the sheaves forces the secondary sheaves apart, which allows the belt to move to a smaller diameter on the secondary. This is the process that shifts the system to a higher gear ratio. In an ideal case, such a combination is capable of producing an overdrive gear a ratio of 0.75:1 in the CVT. The initial reduction provided by the CVT is 3.5:1 

To have better understanding follow the above x-section of  cvt