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013 planetary gear sets
- 2. Planetary Gear Sets We know the following Turning Clutches Allow rotational torque to reach a portion of a planetary gear set Holding Clutches Stops the rotation of a portion of the planetary gear set Bands Stop the rotation of portion of a planetary gear set Puppies are cute!
- 3. Simpson Gear Set Simpson gear sets have 1 common sun 2 carriers 2 ring gears Allows for 3 or 4 speed transmissions when coupled with simple planetary gear set (compound gear set)
- 4. Simpson Gear Types Types 1-4 1 Bands are used for reaction member 2 multiple-disc clutch & band for reaction members 3 multi-disc clutch on one-way & band 4 uses multi-disc clutches, one-way clutch and band for reaction members Types 5-8 Same theory but now the trans will use a third planetary for a Overdrive unit
- 5. Toyota FWD B = Brake F = One-way clutch Note: When two planetary gears sets share a common sun gear (as above), that combination is called a Simpson planetary gear set. 5 C = Clutch
- 6. Ravigneaux Gear Set Ravigneaux gear sets have Two Sun gears of different sizes 1 carrier with two sets of planet gears 1 ring gear Ravigneaux gear sets when combined with simple planetary can have 6-8 gears (LePelletier) Account for types 9-12
- 7. Toyota FWD with Ravigneaux Counter Driven Gear Ravigneaux Planetary Gear Unit U/D Planetary Gear Unit Intermediate Shaft Counter Driven Gear Input Shaft 7
- 8. Toyota Dual Planetary Trans
- 9. Questions? End Planetary Gear Sets
Editor's Notes
- The A245E is a basic FWD transmission (transaxle) mounted in the engine compartment perpendicular to the vehicle's direction of travel. It has three planetary gear sets. The front and rear planetary gear sets operate in the same axis within the transmission. Because the front and rear planetary gear sets share a common sun gear, the combination is called a Simpson planetary gear set. The third planetary gear is the U/D planetary gear set which operates on a separate axis to achieve a compact design. Holding devices include three multi-plate clutches, three multi-plate brakes, and a single band type brake. Note the sun gears ride on (but are independent of) the intermediate shafts. The front carrier and rear ring gear are connected to the upper intermediate shaft which all rotate in unison with the counter drive gear. The speed and direction the upper intermediate shaft turns – and consequently the counter drive gear – depends on which holding devices are applied to the front and rear planetaries. As the counter drive gear turns the counter driven gear, the counter driven gear and the lower intermediate shaft turn at the same speed but in the opposite direction. The lower intermediate shaft is connected to the U/D ring gear so they turn together. The output gears of the transmission are the differential drive pinion and the ring gear it’s connected to. The differential drive pinion is connected to the U/D carrier, so the rotation speed and direction of the U/D carrier is directly related to final vehicle speed and direction. In all gears except fourth gear, the holding devices applied on the U/D planetary gear set result in a speed reduction between the counter driven gear and the output gears. In fourth gear, a different combination of holding devices result in the output gears turning at the same speed as the counter driven gear.
- The U660 is a modern FWD transaxle mounted perpendicular to the vehicle’s direction of travel. It has two planetary gear sets that operate on the same axis within the transaxle housing. The underdrive planetary gear set is a simple planetary gear set. It is mounted closer to the engine. Its sun gear is connected to the input shaft. Its pinion gears are connected to the Ravigneaux front sun gear. The second planetary gear set, mounted farther from the engine, is called a Ravigneaux planetary gear set (pronounced RAV-eh-no). It includes: Front and rear sun gears of different diameters Long and short pinion gears in a single carrier assembly The long pinion gears mesh with the rear sun gear and with the short pinion gears. The short pinion gears mesh with the long pinion gears and with the front sun gear. Both sets of pinion gears mesh with the ring gear and are connected to the counter drive gear. A single ring gear Counter drive gears and counter driven gears are installed in between the two planetary gear sets. These gears transfer torque from the axis of the planetary gear sets to the axis of the differential drive pinion.