CVTs Archives - Transmission Digest
The New Jatco JF015E: When is a CVT not a CVT?

The CVT (continuously variable transmission) concept has been around forever, but CVTs have been on the road now for decades, in one form or another. Although there are several different models of CVT, they all have one thing in common: basic operation.

Over the years there have been variations in CVTs from vehicle model to model, starting with the original DAF European CVTs, up to the first Jatco CVT, Saturn VT20E, ZF VT1, Ford CFT30 and then on to later-model Jatcos. There are CVTs that use a torque converter and some that don’t. A CVT may have a push belt, while others use a drive chain. Electrical components also vary widely among models. In addition, certain models use a direct-drive pump while others use a chain-driven remote pump. The CFT30 uses a pump with oscillating pistons. A CVT will also have a planetary gear set, primarily for reverse.

Stepless Ratios in CVTs

Continuously variable transaxles use pulleys and a drive belt as the components needed to provide the vehicle with stepless gear ratios. The basic construction of a pulley is movable and stationary surfaces (see Figure 1). The drive belt Honda uses, constructed of about 280 elements held together by two 12-layer steel loops, is manufactured by Van Doorne Transmissie (VDT) of the Netherlands, with Honda giving it a little tweaking of its own (see Figure 2).

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CVT World

Technically Speaking

Author: Wayne Colonna, Technical Editor