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| Illustration 1 | g02789605 |
(1) Housing (2) Turbine (3) Impeller (4) Stator (5) Hub (Impeller) (6) Lockup clutch (7) Hub | |
The torque converter is driven by the engine crankshaft. The torque converter consists of an impeller (3), a turbine (2), a lockup clutch (6), and a stator (4). The lockup clutch (6) permits the machine to operate in direct drive in order to keep the power loss at a minimum.
The torque converter housing and impeller are fastened to the flexplate and crankshaft for the engine. The torque converter impeller connects to the transmission pump.
The engine crankshaft turns the rotating housing (1) and impeller (3). The impeller directs oil onto the blades of turbine (2). The oil to the blades causes the turbine to turn. The turbine directs the oil onto stator (4).
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| Illustration 2 | g01261275 |
(10) Cam (11) Race (12) Spring (13) Slot (14) Cam Surface (15) Roller | |
Stator (4) 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 (15) are forced into the narrow end of the slot (13). This prevents the cam and stator assembly from rotating around the carrier. Since the cam is held stationary, the stator cannot turn and the 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.
The output torque requirement can be less than or equal to the input torque. This can occur when ground speed is high and the resistance is low. Then, the turbine will be turning quickly. The oil that flows through the turbine strikes the back of the stator blades so that the stator starts turning in the same direction as the turbine. The cam (10) then rotates so that rollers (15) occupy the wide end of opening (13). The stator (4) is then free to rotate around the carrier. The oil then flows through the turbine and out of the converter.
Turbine (2) turns hub (7). The hub turns the output shaft. Power is sent through the output shaft to the transmission planetary group.
Lockup clutch (6) is part of the torque converter. The lockup clutch is located between the torque converter housing (1) and the turbine (2). The lockup clutch is engaged under all of the following conditions: sufficient input speed to the transmission, sufficient transmission oil pressure and sufficient engine rpm. 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 operating conditions area appropriate. Torque converter and direct drive are provided in second gear, and only direct drive is provided in all the higher gears.
The engine output speed, or the input speed of the torque converter is measured at the torque converter impeller. The output speed of the torque converter is measured at the input to the transmission planetary. This speed is the same speed as the transmission input speed.