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OBJECTIVES

OBJECTIVES. After studying Chapter 5, the reader should be able to: Explain how power can be transferred through a planetary gearset to produce the various ratios. Identify the major components of simple, compound, and complex planetary gearsets.

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OBJECTIVES

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  1. OBJECTIVES After studying Chapter 5, the reader should be able to: • Explain how power can be transferred through a planetary gearset to produce the various ratios. • Identify the major components of simple, compound, and complex planetary gearsets. • Explain the role of the driving and reaction members in producing the different power flows. • Identify the basic gear train arrangements used in automatic transmissions. • Trace the power flow through various planetary gear trains.

  2. FIGURE 5-1 A simple planetary gearset consists of a sun gear, ring gear, planet carrier, plus a group of planet pinion gears. To produce a power flow, one part is the input, one part is held in reaction, and one part becomes the output. RULES OF POWER TRANSFER • The gearset in an automatic transmission must provide a neutral, one or more gear reductions, a 1:1 or directdrive ratio, a reverse, and an overdrive. • Some manufacturers are currently using five-, six-, seven, and even eight-speed transmissions.

  3. FIGURE 5-2 A Simpson gear train transmission. Note that the two gearsets (front and rear) use the same sun gear. Also note that one carrier and the sun gear can be the reaction members. The sun gear and one ring gear can be input members, and the other carrier and ring gear can be output members. (Courtesy of Chrysler Corporation) RULES OF POWER TRANSFER

  4. FIGURE 5-3 A Ravigneaux gearset has two sun gears (one small [sun gear 1] and one large [sun gear 2]), one carrier with a set of short pinions (planet pinions 1) and a set of long pinions (planet pinions 2), and a single ring gear. (Courtesy of Chrysler Corporation) RULES OF POWER TRANSFER

  5. TABLE 5-1 Planetary rules RULES OF POWER TRANSFER

  6. FIGURE 5-4 The gear ratio through a planetary gearset depends on which part is driven, which part is held, and which part is the output. The formula used to calculate the ratio is included with each illustration. Each gear set uses a 40-tooth sun gear and a 76-tooth ring gear. RULES OF POWER TRANSFER • Planetary Gear Ratios • A simple planetary gearset can produce seven different gear ratios, plus neutral. • Changing the gear ratios is done by changing the input (driving) and the reaction (held) member.

  7. FIGURE 5-5 When a transmission or transaxle is viewed from the engine end, the rotation of the torque converter and input shaft is in a clockwise direction. If the gearset is driven by a chain and sprockets, the rotation is counterclockwise. RULES OF POWER TRANSFER

  8. TRANSAXLES • The following descriptions of transmission power flows also apply to transaxles. • Most features of a transaxle are the same as those of a transmission; in the following discussions, we will treat them as the same and only refer specifically to a transmission or a transaxle when necessary. • With the exception of CVTs that use an electromagnetic clutch, all automatic transmissions have the torque converter mounted on the input shaft at the front of the transmission. • RWD transmissions have a single output shaft that connects to either the drive shaft of 2WD vehicles or transfer case for 4WD vehicles.

  9. FIGURE 5-6 This transaxle has a drive shaft for each front wheel. To reduce torque steer, the top unit has equal-length shafts; note the two-part right drive shaft. The lower unit uses a larger tubular shaft on the right side. (Courtesy of Chrysler Corporation) TRANSAXLES

  10. FIGURE 5-7 This transaxle uses a drive chain and two sprockets to transfer torque from the torque converter at the left to the gear train. (Courtesy of BorgWarner, Morse TEC) TRANSAXLES

  11. FIGURE 5-8 This transaxle uses a pair of transfer gears to transfer torque to the transfer shaft and final drive gears. (Courtesy of Chrysler Corporation) TRANSAXLES

  12. FIGURE 5-9 A CD4E transaxle uses a chain (3201) to transfer torque from the planetary gearset (3562) to the final drive (4031) and differential (4541). (Courtesy of Aceomatic Recon) TRANSAXLES

  13. FIGURE 5-10 The park gear can be built into one of the planetary output members like this output ring gear (a) or as a separate member attached to the transmission output shaft (b). Note that B also supports the governor. (a is courtesy of Slauson Transmission Parts, www.slauson.com; b is courtesy of Chrysler Corporation) PARK • Every automatic transmission and transaxle includes a park range. • A shift into park prevents the transmission’s output shaft from turning, holding the vehicle stationary. • The parking gear has gearlike teeth and is mounted on the output member of the transmission.

  14. FIGURE 5-11 When the control rod is moved, the locking cam pushes the pawl into engagement with the parking gear. (Courtesy of Chrysler Corporation) PARK

  15. TRANSMISSION SCHEMATICS • Transmission parts and operation are often illustrated using pictures and cutaway drawings. • They show the bare essentials of the transmission gear train in the simplest way possible. • When you look at the typical cutaway view of a gear train, the transmission is usually split lengthwise through the middle. • This shows the relationship of the parts, but in many cases, it is difficult to tell where one part stops and another begins, making it difficult to trace the path of the power flow.

  16. FIGURE 5-12 The Type 1 gearset is a three-speed Simpson gear train that uses bands to hold the sun gear and reaction carrier. Note that the reaction carrier can also be held by a one-way clutch. TRANSMISSION SCHEMATICS • An easier way to view transmission operation is by using schematics. • Transmission schematics resemble stick drawings.

  17. FIGURE 5-13 Common symbols used in the transmission schematics to illustrate the various parts. TRANSMISSION SCHEMATICS

  18. SIMPSON GEAR TRAIN TRANSMISSIONS • The Simpson gear train is a compound gearset commonly used in many three-speed transmission/transaxles. • Most of the automatic transmissions used in domestic vehicles during the 1960s and 1970s used this gear train. • The better known Simpson gear train transmissions are: • Aisin-Warner: • Chrysler Corporation: • Ford Motor Company: • General Motors: • JATCO: • Toyota

  19. FIGURE 5-14 These gear train types are all Simpson three-speed units that use different apply devices or, in the Type 4,a different gearset arrangement. SIMPSON GEAR TRAIN TRANSMISSIONS

  20. FIGURE 5-15 The one-way clutch of this Type 1 gearset serves as the reaction member in Drive 1.The low-reverse band is applied in manual 1 to allow compression braking. SIMPSON GEAR TRAIN TRANSMISSIONS

  21. FIGURE 5-16 If both the high-reverse and forward clutches are released, then the transmission is in neutral. Note that the sun gear can be of two different sizes. SIMPSON GEAR TRAIN TRANSMISSIONS

  22. TABLE 5-3 Simpson gear train summary TABLE 5-2 Planetary gear actions SIMPSON GEAR TRAIN TRANSMISSIONS

  23. SIMPSON GEAR TRAIN TRANSMISSIONS • Neutral • First Gear • Second Gear • Third Gear • Reverse

  24. FIGURE 5-17 In drive-1, the front ring gear is driven while the rear carrier is held by the one-way clutch (a). A reverse reduction occurs in both the front unit (b) and the rear unit (c). SIMPSON GEAR TRAIN TRANSMISSIONS

  25. FIGURE 5-17 (CONTINUED) In drive-1, the front ring gear is driven while the rear carrier is held by the one-way clutch (a). A reverse reduction occurs in both the front unit (b) and the rear unit (c). SIMPSON GEAR TRAIN TRANSMISSIONS

  26. FIGURE 5-18 The intermediate clutch and intermediate roller clutch hold the sun gear from rotating in second gear in the THM 350, Type 3 gearset. The intermediate overrun band is used in manual-2 for compression braking. (Reprinted with permission of General Motors) SIMPSON GEAR TRAIN TRANSMISSIONS

  27. FIGURE 5-19 In second gear, the ring gear is driven while the sun gear is held, the planet gears walk around the sun gear and force the carrier to revolve at a reduced speed. SIMPSON GEAR TRAIN TRANSMISSIONS

  28. FIGURE 5-20 In third gear, both driving clutches are applied so two members (the ring and sun gears) of the same gearset are driven. This locks the gears and produces a 1:1 gear ratio. SIMPSON GEAR TRAIN TRANSMISSIONS

  29. FIGURE 5-21 In reverse, the sun gear is driven while the carrier is held. The planet gears act as idlers and cause the ring gear to revolve in a reverse direction at a reduced speed. SIMPSON GEAR TRAIN TRANSMISSIONS

  30. TABLE 5-4 Simpson gear train band and clutch application, type 1 SIMPSON GEAR TRAIN TRANSMISSIONS

  31. TABLE 5-5 Simpson gear train band and clutch application, type 3 SIMPSON GEAR TRAIN TRANSMISSIONS

  32. FIGURE 5-22 The full-throttle shift sequence for a Type 1 transmission showing the apply devices and the output shaft speed at the 1–2 and 2–3 upshifts. Reverse is also shown. SHIFT TIMING • As a vehicle accelerates from a stop to cruising speed, the driving and reaction members have to apply and release in an exact operating sequence. • When they apply, they must come on at a precise rate.

  33. SIMPSON GEAR TRAIN PLUS AN ADDITIONAL GEARSET • The Simpson gear train with an additional simple planetary gearset is used to produce a four-speed overdrive transmission or transaxle. • Overdrive

  34. FIGURE 5-23 This A340E transmission sectional view shows the overdrive section between the pump and three-speed planetary gear section. (Courtesy of Toyota Motor Sales USA, Inc.) SIMPSON GEAR TRAIN PLUS AN ADDITIONAL GEARSET

  35. FIGURE 5-24 This Chrysler 42RH transmission cutaway view shows a three-speed, Simpson Type 1 gearset with an overdrive unit at the output end of the transmission. (Courtesy of Chrysler Corporation) SIMPSON GEAR TRAIN PLUS AN ADDITIONAL GEARSET

  36. FIGURE 5-25 An exploded view of the A340E overdrive unit. The O/D one-way clutch provides a 1:1 ratio in D1, D2, and D3.The O/D direct clutch is used in manual gear ranges.The O/D brake pack is applied in D4. (Courtesy of Toyota Motor Sales USA, Inc.) SIMPSON GEAR TRAIN PLUS AN ADDITIONAL GEARSET

  37. FIGURE 5-26 The Type 5, 6, 7, and 8 gearsets illustrate the different four-speed gear train arrangements that combine a Simpson three-speed gearset with an overdrive unit. SIMPSON GEAR TRAIN PLUS AN ADDITIONAL GEARSET

  38. FIGURE 5-27 The full-throttle shift sequence for a Type 6 transmission showing the apply devices and the output shaft speed at the 1–2,2–3,and 3–4 upshifts. Reverse is also shown. SIMPSON GEAR TRAIN PLUS AN ADDITIONAL GEARSET

  39. TABLE 5-6 Simpson gear train plus overdrive band and clutch application, type 6 SIMPSON GEAR TRAIN PLUS AN ADDITIONAL GEARSET

  40. TABLE 5-7 Shift strategy: four speed TABLE 5-8 Shift strategy: five speed SIMPSON GEAR TRAIN PLUS AN ADDITIONAL GEARSET

  41. RAVIGNEAUX GEARSETS • The Ravigneaux gearset uses a single carrier that has two sets of intermeshed planet gears, two sun gears, and a single ring gear. • The planet gears are different lengths. • The two sun gears have different diameters and are independent of each other. • The long pinion gears mesh with the large sun gear, short pinions, and ring gear

  42. FIGURE 5-28 The Type 9,10,11,and 12 gearsets illustrate the different three- and four-speed gear train arrangements that use a single Ravigneaux gearset. RAVIGNEAUX GEARSETS • Two-Speed Ravigneaux Arrangement and Operation • Three-Speed Ravigneaux Arrangement and Operation: First Version • Three-Speed Ravigneaux Arrangement and Operation: Second Version • Four-Speed Ravigneaux Arrangement and Operation

  43. FIGURE 5-29 When a Powerglide is in low gear, the low band is applied to hold the low sun gear stationary; at this time, the long pinions will be driven by the input sun gear and walk around the low sun gear to drive the carrier. (Reprinted with permission of General Motors) HOW WAS THE POWERGLIDE DIFFERENT?

  44. RAVIGNEAUX GEARSETS • Four-Speed Ravigneaux Arrangement and Operation: Second Version • LePelletier Gear Train

  45. FIGURE 5-30 Exploded views of a Ford ATX (a) transaxle and a GM 3L30 (b) transmission gearset. Note the difference in the carriers (27). (Courtesy of Slauson Transmission Parts,www.slauson.com) RAVIGNEAUX GEARSETS

  46. FIGURE 5-31 A stub shaft (not shown) is used to connect the turbine shaft and forward drum (3315) of the Ford 4R70W transmission to the direct clutch housing (3331).The direct clutch is used in third and fourth gears. (Courtesy of Aceomatic Recon) RAVIGNEAUX GEARSETS

  47. FIGURE 5-32 The full-throttle shift sequence for a Type 12 transmission showing the apply devices and the output shaft speed at the 1–2,2–3,and 3–4 upshifts and reverse. RAVIGNEAUX GEARSETS

  48. FIGURE 5-33 This cutaway view of a GM 4L30 transmission shows an overdrive unit as the input of a Type 11, three-speed Ravigneaux gearset. (Reprinted with permission of General Motors) RAVIGNEAUX GEARSETS

  49. FIGURE 5-34 A schematic view of a Type 13, LePelletier six-speed gearset (a) and a clutch application chart (b). RAVIGNEAUX GEARSETS

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