2 Automotive Drivetrains Connect/disconnect engines power to the drive wheel(s) allow for different speed ratios provide for reverse power control for safe turning torque multiplication Purpose:

3 Automotive Drivetrains Transmission Axle assembly Transaxle (fwd) Drive Shaft(s) related components Components:

4 Automotive Drivetrains The turning effort of the crankshaft measured in foot-pounds maximum torque is produced within a narrow RPM range (torque curve) Engine torque:

5 Engine Torque

6 Automotive Drivetrains = work performed at the rate at which it is being done = torque X RPM / 5252 Horsepower

7 Engine Horsepower

8 Automotive Drivetrains Used to apply torque to other rotating parts of the drivetrain used to multiply torque in automobiles Gears

9 Automotive Drivetrains Spur gear (most basic) Helical gear (helix = form a curve) Herringbone gear = 1 gear w/2 helical gears w/teeth angles reversed Bevel gear - cone w/top cutoff hypoid gear - similar to above planetary gear(set) Gear Types

10 Automotive Drivetrains Spur gear

11 Automotive Drivetrains Helical Gear

12 Automotive Drivetrains Straight Bevel Gearset Gears must be perpendicular to each other

13 Automotive Drivetrains Spiral Bevel vs. Hypoid

14 Automotive Drivetrains Planetary Gear

15 Automotive Drivetrains Backlash - the clearance between two meshed gears –measured with a dial indicator end play - axial or end-to-end movement of a gear –also measured with a dial indicator Gear Measurements

16 Torque Multiplication Torque is calculated by multiplying force X distance OR the center of the shaft times (X) the point where the force is exerted

17 Automotive Drivetrains Gears Continued:

18 Automotive Drivetrains Gears continued:

19 Automotive Drivetrains As torque is multiplied power remains unchanged

20 Automotive Drivetrains The mathematical relationship of one gear to another expresses the amount of torque multiplication between two gears ratio = # of teeth of DRIVEN gear / # of teeth of drive gear - OR - ratio = outside diameter of DRIVEN gear/ O.D. of drive gear Gear Ratios:

21 Automotive Drivetrains = a reduction in the driven gears speed = an increase in the driven gears torque Gear Reduction

22 Automotive Drivetrains

23 Automotive Drivetrains If the DRIVING gear in the previous example is producing 250 ft.-lb. of torque how much torque is the DRIVEN gear producing? 4 X 250 = 1000 ft.-lb. torque

24 Automotive Drivetrains Bearings Used to attach a shaft to a common component AND allow for movement or rotation friction reduction

25 Automotive Drivetrains Bushing (simplest type) also called a plain type bearing ball bearing - balls used for friction reduction roller bearing tapered roller Bearing Types

26 Bushing (simplest type) also called a plain type bearing

27 Ball Bearing

28 Roller Bearing

29 Needle Roller Bearing

30 Tapered Roller Bearing

31 Automotive Drivetrains radial or journal bearing thrust bearing Bearing Usage

32 Automotive Drivetrains Bearing preload - the amount of torque- load on a bearing –measured with a torque wrench Bearing Measurements

33 Automotive Drivetrains CLUTCH The engine produces torque Torque is transferred to the drive wheels through a series of gears and shafts How do we disconnect engine power from the drive wheels?