Belt & Pulley

STRUCTURE AND OPERATION

TRANSAXLE : Belt & Pulley


STRUCTURE







MECHANISM

It is composed of a pair of pulleys (the groove width is changed freely in the axial direction) and the steel belt (the steel plates are placed continuously and the belt is guided with the multilayer steel rings on both sides).
The groove width changes according to wrapping radius of steel belt and pulley from low status to overdrive status continuously with non-step. It is controlled with the oil pressures of primary pulley and secondary pulley.

STEEL BELT






It is composed of multiple steel plates (A) and two steel rings (B)
stacked to a several number. The feature of this steel belt transmits power with compression of the steel plate in contrast with transmission of power in pulling with a rubber belt. Friction force is required with the pulley slope to transmit power from the steel plate. The force is generated with the following mechanism:
Oil pressure applies to the secondary pulley to nip the plate. ==> The plate is pushed and extended outward. ==> The steel ring shows withstands. ==> Pulling force is generated on the steel ring. ==> The plate of the primary pulley is nipped between the pulley. ==> Friction force is generated between the steel belt and the pulley.
Therefore, responsibilities are divided by the steel plate that transmits the power with compression and the steel ring that maintains necessary friction force. In this way, the tension of the steel ring is distributed on the entire surface and stress variation is limited, resulting in good durability.

PULLEY

The primary pulley (input shaft side) and the secondary pulley (output shaft side) have the shaft with slope (fixed cone surface), movable sheave (movable cone surface that can move in the axial direction) and oil pressure chamber at the back of the movable sheave.
The movable sheave slides on the shaft to change the groove width of the pulley. Input signals of engine load (accelerator pedal opening), primary pulley speed and secondary pulley speed change the operation pressures of the primary pulley and the secondary pulley, and controls the pulley groove width.