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| Illustration 1 | g00786477 |
(1) Housing (2) Turbine (3) Stator (4) Output shaft (5) One-way clutch (6) Impeller (7) Lockup clutch (8) Hub | |
The torque converter is driven by the engine through a flexible drive coupling. The torque converter consists of an impeller (6), a turbine (2), a lockup clutch (7), and a stator (3) with a one-way clutch (5). The lockup clutch permits the machine to operate in direct drive in order to keep the power loss at a minimum. The one-way clutch holds the stator when the torque converter drive is used. The one-way clutch allows the stator to turn freely when direct drive is used.
The torque converter housing is fastened to the flywheel housing for the engine. Output shaft (4) connects the torque converter to the transmission planetary group.
The flexible drive coupling turns rotating housing (1) and impeller (6). The impeller directs oil onto the blades of turbine (2). This causes the turbine to turn. The turbine directs the oil onto stator (3).
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| Illustration 2 | g01016156 |
(9) Race (10) Cam (11) Spring (12) Slot (13) Cam Surface (14) Roller | |
Stator (3) is connected to cam (10) by the spline. When the hydraulic oil tries to move the stator in the opposite direction to the turbine, rollers (14) are forced into the narrow end of the slot (12). This prevents the cam and stator assembly from rotating around the carrier. Since the cam is held stationary, the stator cannot turn and the one-way clutch is locked up.
The stator now directs most of the oil back to the impeller. The remainder of the oil goes out of the torque converter. The oil, that goes back to the impeller from the stator, moves in the same direction as the rotation of the impeller. Since this oil is moving in the same direction as the impeller, the torque output from the torque converter is multiplied.
Turbine (2) turns hub (8). The hub turns output shaft (4). Power is sent through the output shaft to the transmission planetary group.
Lockup clutch (7) is part of the torque converter. The lockup clutch is located between the flexible drive coupling and the turbine. The lockup clutch is engaged under the following conditions: sufficient input speed to the transmission and output speed from the transmission, sufficient transmission oil pressure, sufficient engine rpm and engagement of retarder. When the lockup clutch is engaged, the impeller and the turbine turn at the same speed as the engine and there is no loss of power in the torque converter. The connection between the engine and the transmission is now direct.
Torque converter drive is available in first gear, second gear and reverse gear. The lockup clutch provides direct drive once the transmission speed and the engine speed are matched.
Direct drive is provided in all the higher gears. The lockup clutch is disengaged during transmission shifts in order to allow a smooth transition between gears.
The input speed of the torque converter is measured at the engine flywheel. This speed is the same speed as the engine output speed. The output speed of the torque converter is measured at the planetary transmission. This speed is the same speed as the transmission input speed.