The torque converter connects the engine to the
planetary transmission. This connection between the
engine and the transmission is a hydraulic connection.
There is no direct mechanical connection between the
engine and the transmission.
The torque converter uses oil to send torque from the
engine to the transmission. When the machine is
working against a load, the torque converter can
multiply the torque from the engine and send a higher
torque to the transmission.
POWER FLOW THROUGH TORQUE CONVERTER
1. Torque converter housing. 2. Flywheel adapter
gear. 3. Gear for the transmission oil pump. 4.
Rotating housing. 5. Drive gear for the oil pumps. 6.
Stator. 7. Outlet passage. 8. Carrier. 9. Output
shaft. 10. Inlet passage. 11. Turbine. 12. Gears (two)
for the hydraulic pump. 13. Impeller.
The oil for the operation of the torque converter
comes from the oil pump for the transmission. The oil
pump is driven by gear (3) and gear (5). An inlet ratio
valve (part of the pressure control valve in the
transmission) controls the maximum oil pressure to the
torque converter. An orifice in the outlet passage
controls the minimum oil pressure in the torque
The rotating housing (4) is connected to the
engine flywheel with splines of gear (2). The impeller
(13) and the drive gear (5) for the oil pump are
connected to the rotating housing. These components
turn with the engine flywheel at engine speed.
The stator (6) is connected to the carrier (8)
which is connected to the torque converter cover. The
stator does not turn.
The turbine (11) is connected to the output shaft
(9). Drive gear (5) is fastened to the impeller and turns
the gears (3) and (12) for the oil pumps.
transmission goes into the torque converter through an
inlet passage (10) in the carrier (8).
The impeller (13) [which turns with the rotating
housing (4) at engine speed] makes the oil go toward
the outside of the impeller, around the inside of the
rotating housing (4), and against the blades of the
turbine (11). The oil that hits the turbine blades causes
the turbine (11) and the output shaft (9) to turn. This
sends torque through a drive shaft to transfer gears and
to the input shaft of the transmission.
4. Rotating housing. 6. Stator. 11. Turbine. 13.
After the oil hits the turbine blades, the oil goes
toward the inside of the turbine (11). As the oil goes
from the turbine, it moves in a direction opposite the
direction of impeller rotation. The stator (6) causes the
oil to change direction and go back into the impeller (13)
in the direction of rotation. This gives an increase to the
impeller oil output which gives an increase to the torque
output from the turbine (11).
The larger the difference between the speeds of
rotation of the impeller (13) and the turbine (11) the
larger the output torque becomes.
Oil from the outlet passage (7) goes to the oil