Multi-mode CVT

Abstract

A multi-mode continuously variable transmission is disclosed. The continuously variable transmission includes four shift elements to establish three forward travel gears and one reverse travel gear. Two of the forward travel gears use recirculating power flow paths in which much less power is transmitted through the variator than through the transmission. The pulleys of both variator mechanisms rotate about axes that are offset relative to the input axis such that neither pulley is partially submerged in the converter fluid.

Description

technical field [0001] This disclosure relates to the field of vehicle transmissions. More specifically, the present disclosure relates to gear transmissions for continuously variable transmissions having multiple operating modes. Background technique [0002] Many vehicles are used over a wide range of vehicle speeds including both forward and reverse motion. However, some types of engines can only operate efficiently within a narrow speed range. Therefore, transmissions capable of efficiently transmitting power at various gear ratios are generally employed. When the vehicle is at low speeds, the transmission typically operates at a high gear ratio, which multiplies the engine torque for improved acceleration. At high vehicle speeds, operating the transmission at low gear ratios allows engine speeds to be associated with quiet, fuel-efficient cruising. Typically, a transmission has a housing mounted to the vehicle's structure, an input shaft driven by the engine's crank...

AI Technical Summary

Problems solved by technology

The upper and lower ratio limits of the variator may not match the ratio requirements of the vehicle

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