(4) Stator (converter)
(5) Hub (Impeller)
(6) Lockup clutch (disk-friction) (plate) (piston-clutch)
(7) Hub (turbine)
The torque converter is driven by the engine crankshaft. 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). The lockup clutch (6) permits the machine to operate in direct drive in order to keep the power loss at a minimum.
(8) Cam (freewheel)
(9) Race (freewheel)
(10) Spring (freewheel)
(12) Cam Surface
Stator (4) is connected to cam (8) by the spline. The hydraulic oil tries to move the stator in the opposite direction to the turbine. Rollers (13) are forced into the narrow end of the slot (11). With the rollers in the narrow end of the slot, the cam and stator assemblies are restricted from rotating around the carrier. Since the cam is held stationary, the stator cannot turn.
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. Less than or equal torque 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 contacts the back of the stator blades. The stator will start turning in the same direction as the turbine. The cam (8) then rotates so that rollers (13) occupy the wide end of opening (11). 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.
(14) Torque convertor inlet relief valve
(15) Torque convertor lockup clutch solenoid
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 from engine and sufficient transmission oil pressure. The lockup clutch is engaged by the lockup solenoid (15). When the lockup clutch is engaged, the impeller and the turbine turn at the same speed as the engine. 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 all gears and directions. The lockup clutch provides direct drive once the transmission operating conditions area appropriate. The direct drive feature is automatically enabled in third forward, fourth forward, and reverse gears. If the operator chooses, direct drive can be enabled in second forward and reverse 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.
|(14) Torque convertor inlet relief valve|
The torque convertor relief valve (14) controls the pressure the transmission oil to the torque convertor. As the oil pressure to the torque convertor rises above the set point of the relief valve, the oil pressure will over come the spring and be diverted to the tank. The torque convertor relief valve is located in the torque convertor control valve on the left-hand side of the transmission.