1 / 36

Manual Drivetrains and Axles Fourth Edition

Manual Drivetrains and Axles Fourth Edition. Tom Birch and Chuck Rockwood. Chapter 3 Introduction to Drivetrains. The vehicle’s drivetrain transfers power from the engine to the drive wheels. The front wheels are driven in a front-wheel drive (FWD) vehicle.

wray
Download Presentation

Manual Drivetrains and Axles Fourth Edition

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Manual Drivetrains and AxlesFourth Edition Tom BirchandChuck Rockwood Chapter 3 Introduction to Drivetrains

  2. The vehicle’s drivetrain transfers power from the engine to the drive wheels. The front wheels are driven in a front-wheel drive (FWD) vehicle.

  3. Vehicles that drive the rear wheels are called rear-wheel drive (RWD).

  4. Some vehicles drive all four wheels and they are called four-wheel drive (4WD). If all four wheels are driven all of the time, they are called all-wheel drive (AWD).

  5. The drivetrain consists of a clutch, manual transmission, final drive, and differential or an automatic transmission with torque converter, final drive, and differential.

  6. Transaxles combine the transmission, final drive, and differential into one unit.

  7. The drivetrain: • Allows the driver to control the power flow • Multiplies engine torque • Controls engine speed

  8. Torque is a rotating force that is produced by an engine, but the engine does not produce enough torque at low speeds to move a vehicle. But, the speed will be reduced

  9. Torque is increased using a gearset; if the driven gear is twice as big as the driving gear, torque will be doubled, twice as much. This is called a 2:1 ratio.

  10. Animation: External Gears PCMAC

  11. As power travels through an external gearset, the driven gear will revolve in the opposite direction as the driving gear.

  12. If same-direction rotation is desired, an idler gear can be used with an external gear train or an internal gear can be used.

  13. Animation: External Gears with Idler PCMAC

  14. Helical gears are used in most transmissions because they run quieter than spur gears.

  15. But, the driving force on helical gears produces a side thrust that must be absorbed by thrust washers.

  16. Bevel gears are used when the input and output shafts are not parallel like the four gears in this differential.

  17. A hypoid gearset is commonly used in the final drive of RWD vehicles. Note how the hypoid drive pinion shaft is below the center of the ring gear.

  18. Most automatic transmissions use planetary gearsets. They have three major portions:

  19. Animation: Planetary Gear Systems in Overdrive PCMAC

  20. Animation: Planetary Gear Systems in Reduction PCMAC

  21. Different gearsets provide the ratios for the various gear ranges in a transmission.

  22. Engine torque is multiplied by the transmission’s gear ratio. This torque is multiplied by the final drive ratio and divided by tire diameter to get the tractive force that moves the vehicle.

  23. The gearset of this 5-speed transmission provides 6 power flow paths, one for reverse. The 3-4 synchronizer has been shifted to lock 3rd gear to the output shaft. Power flow through the two gear reductions will give a ratio of about 1.3:1.

  24. The clutch connects the engine’s power flow to the transmission smoothly for easy startups and interrupts the power flow so the driver can shift gears.

  25. Automatic transmissions use hydraulic controlled, multiplate clutches and bands along wiyh one-way clutches to route the power flow through planetary gearsets.

  26. Some automatic transmissions are like manual units with multiplate clutches in place of the synchronizer assemblies.

  27. Continuously variable transmissions, CVTs, change gear ratios by changing the width and diameter of the driving and driven pulleys.

  28. Animation: CVT PCMAC

  29. This 4-speed transaxle has an input shaft (E), mainshaft (D), and differential (J) that has the final drive ring gear (G) mounted on it.

  30. The differential allows the axle shafts to rotate at different speeds so vehicles can turn corners.

  31. The driveshaft in RWD vehicles transfers power from the transmission to the rear, drive axle. Universal joints let the shaft change angle and length as the axle moves over bumps.

  32. Animation: RWD Driveshaft PCMAC

  33. Two driveshafts in a FWD vehicles transfer power from the transaxle to the front tires. Constant velocity, CV, joints provide sharp, vibration-free turning angles.

  34. Animation: FWD Driveshafts PCMAC

  35. RWD drive axles have the final drive gears that turn the power flow, the differential, and two axle shafts that transfer power to the wheels.

  36. 4wd and AWD vehicles use a variety of drivetrains.

More Related