2.1.1 TORQUE CONVERTER

2.1.1 TORQUE CONVERTER

The torque converter consists of a pump wheel, a turbine wheel and a stator wheel as shown in Figure 2.2.

As the engine is started, the pump wheel is driven and the fluid inside the pump wheel begins to be ejected along with the row of pump wheel vanes under centrifugal force, flowing into the row of turbine wheel vanes to transmit the torque to the output shaft. The direction of fluid leaving the turbine wheel is changed by the stator wheel so that it may flow into the pump wheel at a proper angle. At this time, reaction torque pushing the stator is created so that the output torque exceeds the input torque by this reaction torque.

As the rotational speed of the turbine wheel increases enough to get closer to the input rotational speed, the angle change in the fluid will become smaller and the output shaft torque will decrease, finally letting the fluid flow into the row of stator vanes in the reverse direction, causing reverse reaction torque. As a result of this, the output shaft torque will become smaller than the input shaft torque. To prevent this from happening, the stator wheel is designed to rotate freely when reaction torque acts in the reverse direction. The output torque is kept equal to the input torque so that highly effective operation is ensured.

Since the phase of torque transmission is converted by the mechanical means, this type of torque conversion is called 2-phase type, which ensures smooth and effective operation.

The pump wheel of the torque converter is connected through the input plate to the engine flywheel, with the pump wheel boss gear engaged with the idle gear for driving the charging pump.

INPUT PLATE TURBINE WHEEL

PUMP WHEEL

STATOR WHEEL STATOR SUPPORT

ONE-WAY CLUTCH

Fig. 2.2 Torque Converter