Automotive Drivetrains Connect/disconnect engines power to the drive wheel(s) allow for different...
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Transcript of Automotive Drivetrains Connect/disconnect engines power to the drive wheel(s) allow for different...
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
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Purpose:
Automotive Drivetrains
• Transmission• Axle assembly • Transaxle (fwd)• Drive Shaft(s)• related components
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Components:
Automotive Drivetrains
• The turning effort of the crankshaft• measured in pounds per foot• maximum torque is produced
within a narrow RPM range (torque curve)
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Engine torque:
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Engine Torque
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Automotive Drivetrains
= work performed at the rate at which it is being done
= torque X RPM / 5252
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Horsepower
Engine Horsepower
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Automotive Drivetrains
• Used to apply torque to other rotating parts of the drivetrain• used to multiply torque in
automobiles
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Gears
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)
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Gear Types
Automotive Drivetrains
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Spur gear
Automotive Drivetrains
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Helical Gear
Automotive Drivetrains
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Straight Bevel Gearset
Gears must be perpendicular to each other
Automotive Drivetrains
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Spiral Bevel vs. Hypoid
Worm Gear
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Automotive Drivetrains
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Planetary Gear
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
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Gear Measurements
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Torque MultiplicationTorque is calculated by
multiplying force X distanceOR
the center of the shaft times (X)
the point where the force is exerted
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Automotive Drivetrains
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Gears Continued:
Automotive Drivetrains
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Gears continued:
Automotive Drivetrains
As torque is multiplied power remains unchanged
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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
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Gear Ratios:
Gear Ratio
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Automotive Drivetrains
= a reduction in the driven gears speed
= an increase in the driven gears torque
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Gear Reduction
Automotive Drivetrains
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Automotive DrivetrainsIf the DRIVING gear in the previous example is producing 250 ft.-lb. of
torque how much torque is the DRIVEN gear producing?
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4 X 250 = 1000 ft.-lb. torque
Automotive DrivetrainsBearings
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•Used to attach a shaft to a common component AND allow for movement or rotation
•friction reduction
Automotive Drivetrains
• Bushing (simplest type) also called a plain type bearing
• ball bearing - balls used for friction reduction
• roller bearing
• tapered roller
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Bearing Types
Bushing (simplest type) also called a plain type
bearing
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Ball Bearing
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Roller Bearing
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Needle Roller Bearing
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Tapered Roller Bearing
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Automotive Drivetrains
• radial or journal bearing
• thrust bearing
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Bearing Usage
Automotive Drivetrains
• Bearing preload - the amount of torque- load on a bearing–measured with a torque wrench
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Bearing Measurements
Automotive Drivetrains
CLUTCH38
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?