Continuously Variable Transmission

What is a CVT or a Continuously Variable Transmission? It is an Automatic transmission that can change gear ratios depending on vehicle speed, engine power or RPM and load. Engines have different RPM range where they deliver engine best power and engine efficiency. Its purpose is to allow the engine operate in an optimal power for varying driving conditions. It consist of three different components, a Primary Clutch, Secondary Clutch and a Belt. The primary clutch has two faces which are the stationary sheave that is connected at the engine crankshaft and a movable sheave that works in and out to engage the belt. The same with the secondary clutch is has also a stationary sheave and a movable sheave.

Lets start with the Secondary Clutch, this is where you can find the flyballs or rollers and ramp plate locations. As the throttle is depressed, the engine revs increase, centrifugal force pushes the flyball weights outward and up the ramp-plates surface. This will cause the sliding variator to move toward the outer fixed pulley half. As the variator slides closer to the Secondary Clutch it applies pressure to the drive belt that sits in between the angled faces of the front pulley half and the variator so that it forces the belt out to a higher gear ratio. This is the basic operation of the Secondary Clutch. Higher engine top speeds cause the belt to go outward changing the gear ratios.

Moving onto the Primary Clutch, has a center spring that holds together the halves of the Primary Clutch. Center spring is a large and powerful spring that make sure that the gearing is at correct level. Its has also three clutch springs that allows the clutch to bite. The front half of the Primary Clutch is placed under pressure by the center spring to make sure that the best gearing is at best tension. There are angled grooves that the pulley travels on, this is to ensure that the gearing ratio is not affected by the belt travelling at high speed.