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
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.
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.
Oil from the hydraulic controls of the 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 cooler.