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Automotive Drivetrains. Automotive Drivetrains. Purpose:. Connect/disconnect engines power to the drive wheel(s) allow for different speed ratios provide for reverse power control for safe turning torque multiplication. Automotive Drivetrains. Components:. Transmission Axle assembly
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Automotive Drivetrains Purpose: • Connect/disconnect engines power to the drive wheel(s) • allow for different speed ratios • provide for reverse • power control for safe turning • torque multiplication
Automotive Drivetrains Components: • Transmission • Axle assembly • Transaxle (fwd) • Drive Shaft(s) • related components
Automotive Drivetrains Engine torque: • The turning effort of the crankshaft • measured in foot-pounds • maximum torque is produced within a narrow RPM range (torque curve)
Automotive Drivetrains Horsepower = work performed at the rate at which it is being done = torque X RPM / 5252
Automotive Drivetrains Gears • Used to apply torque to other rotating parts of the drivetrain • used to multiply torque in automobiles
Automotive Drivetrains Gear Types • 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)
Automotive Drivetrains Spur gear
Automotive Drivetrains Helical Gear
Automotive Drivetrains Straight Bevel Gearset Gears must be perpendicular to each other
Automotive Drivetrains Spiral Bevel vs. Hypoid
Automotive Drivetrains Planetary Gear
Automotive Drivetrains Gear Measurements • 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
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
Automotive Drivetrains Gears Continued:
Automotive Drivetrains Gears continued:
Automotive Drivetrains As torque is multiplied power remains unchanged
Automotive Drivetrains Gear Ratios: • 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
Automotive Drivetrains Gear Reduction = a reduction in the driven gears speed = an increase in the driven gears torque
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
Automotive Drivetrains Bearings • Used to attach a shaft to a common component AND allow for movement or rotation • friction reduction
Automotive Drivetrains Bearing Types • Bushing (simplest type) also called a plain type bearing • ball bearing - balls used for friction reduction • roller bearing • tapered roller
Automotive Drivetrains Bearing Usage • radial or journal bearing • thrust bearing
Automotive Drivetrains Bearing Measurements • Bearing preload - the amount of torque- load on a bearing • measured with a torque wrench
CLUTCH Automotive Drivetrains 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?