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:


• Transmission• Axle assembly • Transaxle (fwd)• Drive Shaft(s)• related components

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Components:


• 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:

Engine Torque

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= 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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• Used to apply torque to other rotating parts of the drivetrain• used to multiply torque in

automobiles

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Gears


• 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


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Spur gear


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Helical Gear


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Straight Bevel Gearset

Gears must be perpendicular to each other


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Spiral Bevel vs. Hypoid

Worm Gear

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Planetary Gear


• 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

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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Gears Continued:


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Gears continued:


As torque is multiplied power remains unchanged

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• 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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= a reduction in the driven gears speed

= an increase in the driven gears torque

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Gear Reduction


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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


• 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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• radial or journal bearing

• thrust bearing

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Bearing Usage


• Bearing preload - the amount of torque- load on a bearing–measured with a torque wrench

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Bearing Measurements


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?

automotive drivetrains connect/disconnect engines power to the drive wheel(s) allow for different...

Documents

driving gear

curveherringbone gear

gear ratios

gear measurements

engine torque

teeth of drive gear

teeth of driven gear

driven gears torque