53Y D8L TRACK-TYPE TRACTOR Operacin de SistemasNmero de publicacin SENR2336-00 Fecha de publicacin 1981/09/01 Fecha de actualizacin 1997/10/23 Torque Divider TORQUE DIVIDER1. Flywheel.2. Ring gear.3. Housing.4. Impeller.5. Inlet passage.6. Carrier.7. Yoke.8. Sun gear.9. Planet gears.10. Planet carrier.11. Turbine.Page 1 of 5 Copyright 1991, 2011 Caterpillar Inc. All Rights Reserved.17/08/2011 file://C:\SIS\TMP\sis521prt.html12. Stator.13. Outlet passage.14. Output shaft.The torque divider connects the engine to the planetary transmission. This connection is both a hydraulic connection and a mechanical connection. The hydraulic connection is through a torque converter. The mechanical connection is through a planetary gear set.The torque converter uses oil from the transmission charging pump 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 making an increase in the mechanical advantage through its gears. This torque multiplication also makes an increase as the load on the machine becomes higher. During no load conditions, neither the torque converter or the planetary gear set can multiply the torque from the engine.The torque divider is installed into the engine flywheel (1). The torque divider housing is installed on the engine flywheel housing. Output shaft (14) is connected to yoke (7). Yoke (7) is connected to the planetary transmission through a drive shaft.The components of the planetary gear set are: sun gear (8), planet carrier (10), planet gears (9) and ring gear (2). Sun gear (8) is connected to the flywheel by splines. Planet carrier (10) is connected to output shaft (14) by splines. Planet gears (9) are held by planet carrier (10) and are engaged with the sun gear (8) and ring gear (2).The components of the torque converter are: housing (3), impeller (4), turbine (11) and stator (12). Housing (3) is connected to flywheel (1) by splines. Impeller (4) is connected to housing (3). Turbine(11) is connectd to ring gear (2) by splines. Stator (12) is connected to carrier (6) and can not turn.

TORQUE CONVERTERPage 2 of 5 Copyright 1991, 2011 Caterpillar Inc. All Rights Reserved.17/08/2011 file://C:\SIS\TMP\sis521prt.html1. Flywheel.2. Ring gear.3. Housing.4. Impeller.5. Inlet passage.6. Carrier.7. Yoke.8. Sun gear.9. Planet gears.10. Planet carrier.11. Turbine.12. Stator.13. Outlet passage.14. Output shaft.Torque Converter OperationOil for the operation of the torque converter goes 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) to turbine (11). The force of the oil hitting the blades of the turbine causes the turbine to turn. Since the turbine is connected to ring gear (2), torque is sent to planet gears (9). At this point in time, the torque given to the turbine by the force of the oil from the impeller can not be more than the torque output of the engine to the impeller.As the oil goes from the turbine, it moves in a direction opposite to the direction of impeller (4) rotation. Stator (12) causes the oil to change direction. Since the stator is connected to carrier (6) and can not turn, most of the oil is sent back to impeller (4). The remainder of the oil goes from the stator through outlet passage (13) 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. This extra force can give an increase to the torque output of the engine to the turbine. The larger the difference between the speeds of the impeller and the turbine, the larger the amount of force of the oil from the stator. Since it is the load on the machine that changes the speed of the turbine, the higher the load, the larger the difference in the speeds of the impeller and the turbine. It is the different loads on the machine that control the amount of torque multiplication that the force of the oil from the stator can add.Torque Divider OperationThe torque converter is driven by the engine through housing (3). The planetary gear set is driven by the engine through sun gear (8). These connections let the torque output of the engine go in two Page 3 of 5 Copyright 1991, 2011 Caterpillar Inc. All Rights Reserved.17/08/2011 file://C:\SIS\TMP\sis521prt.htmlseparate directions. Because of the larger radius of ring gear (2), most of this torque is sent by the torque converter through the ring gear to planet gears (9). The remainder of the torque is sent by sun gear (8) to planet gears (9). If planet carrier (10) has no resistance to rotation (no load), sun gear (8), planet gears (9), planet carrier (10) and ring gear (2) will turn atthe same speed. The torque from the converter and from the planetary gear set is now through the planet carrier to output shaft (14) and the planetary transmission. Neither the torque converter or the planetary gear set can multiply the torque from the engine when they turn at the same speed.When the machine has a load, planet carrier (10) has a resistance to rotation. Since sun gear (8) is turning at the rpm of the engine, this resistance to rotation causes planet gears (9) to turn on their shafts. Their rotation is opposite the rotation of ring gear (2). This causes a decrease in the speed of the ring gear. Since turbine (11) is connected to the ring gear, a decrease in speed will cause the torque converter to multiply the torque of the engine from housing (3). The torque multiplication is sent to planet carrier (10) and the output shaft through the ring gear.With the decrease in the speed of the ring gear, the torque of the engine through sun gear (8) and the planetary gear set also multiplies. This torque multiplication is also sent to planet carrier (10) and the output shaft.If the resistance to rotation of planet carrier (10) becomes higher (more load on the machine), the speed of the ring gear will decrease more. The slower speed will let the torque multiplication through both the torque converter and the sun gear become higher. If the resistance to rotation of the planet carrier becomes high enough, the ring gear will stop. During some very high load conditions, the rotation of the planet carrier and the output shaft will also stop. This will cause the ring gear to turn slowly in the opposite direction. At this time the torque multiplication of the torque converter and the sun gear is at its maximum.Torque Divider LubricationOil for the lubrication of the torque divider bearings and the planetary gear set comes from the supply used for the operation of the torque converter. The bearings constantly run in oil. Bearings and gears in planetary gear set and the pilot bearing get lubrication through passages in the output shaft.Outlet Relief Valve For The Torque ConverterThe outlet relief valve for the torque converter is fastened to the right hand side of the torque converter case.

LOCATION OF OUTLET RELIEF VALVEPage 4 of 5 Copyright 1991, 2011 Caterpillar Inc. All Rights Reserved.17/08/2011 file://C:\SIS\TMP\sis521prt.html

COMPONENTS OF THE RELIEF VALVE1.Body. 2. Inlet passage. 3. Outlet passage. 4. Poppet valve. 5. Valve spool. 6. Shims. 7.Spring.The outlet relief valve controls the maximum pressure in the torque converter. The setting of the outlet relief valve is about 550 kPa (80 psi). From the outlet relief valve, the oil goes through outlet passage (3) to the power train oil cooler.Oil goes into body (1) through inlet passage (2). The oil goes through a hole in valve spool (5) into the chamber between poppet valve (4) and valve spool (5). The oil moves valve spool (5) against the force of spring (7) when the pressure of the oil becomes greater than the force of the spring. The movement of valve spool (5) permits the oil to flow through outlet passage (3).Copyright 1991, 2011 Caterpillar Inc. All Rights Reserved. Page 5 of 5 Copyright 1991, 2011 Caterpillar Inc. All Rights Reserved.17/08/2011 file://C:\SIS\TMP\sis521prt.html