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| Illustration 1 | g00465167 |
(1) Flywheel (2) Ring gear (3) Housing (4) Impeller (5) Inlet passage (6) Carrier (7) Yoke (8) Output shaft (9) Outlet passage (10) Stator (11) Turbine (12) Sun gear (13) Planetary gears (14) Planetary carrier | |
The torque divider is a unit of a planetary gear set and of a torque converter.
The torque converter connects the engine to the planetary transmission. The connection is both a hydraulic connection and a mechanical connection. The hydraulic connection is through the torque converter turbine. The mechanical connection is through a planetary gear set.
The torque converter uses oil from the charge pump section in the torque converter in order to multiply the torque to the transmission. When the machine works against a low load, the torque multiplication is low. When the machine works against a high load, the torque multiplication is higher. A higher torque can then be sent to the transmission during high load conditions.
The planetary gear set also multiplies the torque from the engine by increasing the mechanical advantage through the gears. The torque multiplication increases as the load on the machine increases.
During no-load conditions, neither the torque converter nor the planetary gears can multiply the torque from the engine.
The torque converter is installed onto engine flywheel (1). The torque converter housing is installed on the engine flywheel housing. Output shaft (8) is connected to yoke (7). Yoke (7) is connected to the planetary transmission through a drive shaft.
These components are the main components of the planetary gear set: sun gear (12), planetary carrier (14), planetary gears (13) and ring gear (2) .
Sun gear (12) is connected to the flywheel by splines. Planetary gears (13) are mounted on planetary carrier (14). The planetary gears are engaged with sun gear (12) and with ring gear (2).
These components are the main components of the torque converter: housing (3), impeller (4), turbine (11) and stator (10) .
Housing (3) is connected to flywheel (1) by splines. Impeller (4) is connected to housing (3). Turbine (11) is connected to ring gear (2) by splines. Stator (10) is connected to carrier (6). The stator cannot turn.
Torque Converter Operation
Oil for the operation of the torque converter flows through inlet passage (5) in carrier (6) to impeller (4). The rotation of the impeller gives force to the oil. The impeller sends the oil toward the outside of the impeller, around the inside of housing (3), and to turbine (11).
The force of the oil against the blades of the turbine turns the turbine. Since the turbine is connected to ring gear (2), torque is sent to planetary gears (13). The torque that is sent to the turbine by the force of the oil from the impeller cannot be more than the torque output of the engine to the impeller.
The oil that is flowing from the turbine moves in a direction that is opposite to the rotation of impeller (4). Stator (10) changes the direction of the oil. The stator is connected to carrier (6) and the stator cannot turn. Therefore, most of the oil is sent back to impeller (4). The remainder of the oil flows from the stator, through outlet passage (9), and to the oil cooler.
The force of the oil from the stator can now add to the torque output from the engine to the impeller. The extra force adds to the torque output of the engine to the turbine. The force of the oil that is coming from the stator is determined by the difference in speed between the turbine and the impeller. The amount of force of the oil increases as the difference in the speed of the two components increases.
The load on the machine changes the speed of the turbine. When the load is higher, the difference in speed between the turbine and the impeller increases. The different loads on the machine control the amount of torque multiplication that can be added by the force of the oil from the stator.
Torque Divider Operation
The torque converter is driven by the engine through housing (3). The planetary gear set is driven by the engine through sun gear (12). These connections allow the torque output of the engine to go in two separate directions.
Because of the larger radius of ring gear (2), most of the torque is sent by the torque converter through the ring gear to planetary gears (13). The remainder of the torque is sent by sun gear (12) to planetary gears (13). Sun gear (12), planetary gears (13), planetary carrier (14) and ring gear (2) turn at the same speed when planetary carrier (14) has no resistance to rotation.
The torque from the torque converter turbine and from the planetary gear set is sent through the planetary carrier to output shaft (8) and to the planetary transmission. When the torque converter and the planetary gears turn at the same speed, torque from the engine cannot be multiplied.
When the machine operates under a load, planetary carrier (14) has a resistance to rotation. Since sun gear (12) turns at the speed of the engine, the resistance to rotation turns planetary gears (13). The rotation is opposite to the rotation of ring gear (2). The opposite rotation of planetary gears (13) decreases the speed of the ring gear.
Since turbine (11) is connected to the ring gear, a decrease in speed causes the torque converter to multiply the torque of the engine from housing (3). The torque multiplication is sent to planetary carrier (14) and to the output shaft through the ring gear.
As the speed of the ring gear decreases, the torque of the engine is multiplied through sun gear (12) and through the planetary gear set. The torque multiplication is sent to planetary carrier (14) and to the output shaft.
When the machine operates under higher load, the resistance to rotation of planetary carrier (14) increases. Then, the speed of the ring gear decreases. The slower speed allows higher torque multiplication through the torque converter turbine and through the sun gear.
If the resistance to rotation of the planetary carrier becomes high enough, the ring gear stops. During some very high load conditions, the rotation of the planetary carrier and the rotation of the output shaft also stop. The stopped output shaft causes the ring gear to turn slowly in the opposite direction. The torque multiplication of the torque converter turbine and of the sun gear is at the maximum.
Torque Divider Lubrication
Lubrication oil for the torque divider bearings and for the planetary gears comes from the supply to the torque converter. The bearings constantly run in oil. Bearings and gears in the planetary gear set and the pilot bearings receive lubrication through passages in the output shaft.