Group One

Group One Elements
Elements providing the mechanical torque flow through the transmission. These elements are:

- Planetary gear set
- Multiplate clutches
- Primary pulley
- Steel drive belt
- Secondary pulley
- Pinion shaft
- Differential unit


Group One Components
Planetary Gear Set

The planetary gear set enables the transmission to provide a drive torque in two directions, forward and reverse, to the drive shafts. Engine torque always enters the transmission through the planet carrier via the input shaft. This carrier can be directly connected to the sun-wheel by the forward multi-plate clutches. When it does, the epicyclic gear set rotates as one unit, and engine torque is transmitted directly to the primary pulley. The planet gears do not transmit any torque, therefore no mechanical loss will occur in the planetary gear set and the primary pulley will rotate in the same direction as the engine. This is the forward drive mode.

In reverse mode, the annulus of the planetary gear set is held stationary by the reverse multi-plate clutches. Three pairs of planet gears are driven by the planet carrier, forcing the sun-wheel to rotate in the opposite direction.


Multiplate Clutches
There are two Multiplate wet clutch packs; one forward and one reverse. Each pack has three friction plates providing six friction surfaces. Hydraulic pressure controls the clutches to allow the vehicle to move away smoothly regardless of the degree of throttle opening and by controlling the slip, allow the vehicle to be held stationary after a drive gear is engaged. Oil from the oil cooler is directed to the clutch plates to prevent overheating of the friction surfaces.


Primary Pulley, Secondary Pulley, Steel Belt
The main design feature of the ECVT is a pair of steel "V " shaped pulleys connected by a steel drive belt. The distance between centers of the primary and secondary pulley is 155 mm. Each pulley consists of one fixed half and one movable half, both having an 11 degree sloping sides. A 24 mm wide "Van Doorne" push type drive belt is used to transfer torque between the pulleys. The belt is lubricated and cooled by an oil jet from a nozzle. Both moving halves are situated diagonally opposite to each other in order to reduce misalignment of the drive belt during shifting.

The steel drive belt has approximately 450 segments and is held together by 24 steel bands, 12 on each side. All the segments are of the same thickness.


Pinion Shaft
The pinion shaft creates a two-set helical gear reduction between the secondary pulley and the crown wheel. In this way, the rotational direction of the drive shafts will be correct. The reduction between the secondary pulley and the drive shafts can be made large enough to give good vehicle performance. The pinion shaft is supported by two conical bearings, one in the clutch housing and one in a separate bearing support.


Differential
Drive torque on the crown wheel is transmitted to the vehicle wheels via a bevel gear differential, just as in a manual transmission. The crown wheel is bolted to the differential case with 8 bolts. The drive shafts are fitted to the differential with conventional CV joints and seals. Conical bearings are used to support the differential.