drive shaft and transfer case technology
DESCRIPTION
68. Chapter. Drive Shaft and Transfer Case Technology. Objectives. After studying this chapter, you will be able to: Identify and describe the parts of a modern drive shaft assembly. Explain the functions of a drive shaft. Describe the different types of universal joints. - PowerPoint PPT PresentationTRANSCRIPT
68Drive Shaft and Transfer
Case Technology
Chapter
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Objectives
After studying this chapter, you will be able to:• Identify and describe the parts of a modern drive
shaft assembly.• Explain the functions of a drive shaft.• Describe the different types of universal joints.• List the different types of drivelines.• Explain the basic operation of a transfer case.• Correctly answer ASE certification test questions
that require a knowledge of drive shafts and transfer cases.
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly
Drive shaft assembly components• Slip yoke
– Connects transmission output shaft to front universal joint
• Drive shaft– Hollow metal tube that transfers turning power from
front universal joint to rear universal joint
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly (Cont.)
• Rear universal joint– Flex joint connecting drive shaft to rear yoke
• Rear yoke– Holds rear universal joint and transfers torque to
gears in rear axle assembly and differential
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly (Cont.)
(Mazda)
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Functions of Drive Shaft Assembly
• Sends turning power from transmission to rear axle assembly
• Flexes and allows vertical movement of rear axle assembly
• Provides sliding action to adjust for changes in driveline length
• Provides smooth power transfer
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Drive Shaft Operation
• Transmission output shaft turns slip yoke• Slip yoke then turns front universal joint, drive
shaft, rear universal joint, and rear yoke on differential
• Differential contains gears that transfer power to rear drive axles
• Axles rotate wheels
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Driveline Flex
• When tires strike a bump in the road, rear suspension moves upward and springs are compressed
• Universal joints – Let driveline flex as rear axle moves up and down – Protects drive shaft from any damage caused by
movement
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Slip Yoke
• Slip yoke, or slip joint• Splined to transmission
output shaft • Allows for changes in
driveline length by sliding in and out of transmission
(Ford)
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Slip Yoke (Cont.)
• Extension housing bushing – Supports slip yoke as it spins in transmission
• Transmission rear seal – Rides on slip yoke and prevents fluid leakage from
rear of transmission
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Rear Yoke
• Rear yoke is yoke bolted to outer end of pinion gear on rear axle assembly
• It transfers torque to gears in rear axle assembly– Rear universal joint held by this yoke
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Drive Shaft
• Drive shaft or propeller shaft– Hollow steel tube with permanent yokes welded on
each end– Very strong and light
• Spins much faster than wheels and tires • It must be straight and perfectly balanced
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly
(Toyota)
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Drive Shaft Balance
• Drive shaft must be perfectly balanced, with its weight evenly distributed around its centerline
• Drive shaft balancing weights – Welded to shaft to reduce vibration
• Drive shaft vibration damper – Large, ring shaped weight mounted on rubber – Helps keep shaft spinning smoothly by absorbing
torsional vibration
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Universal Joints
• Universal joint or U-joint • Swivel connection capable
of transferring turning force between shafts at angle to one another
• Simple universal joint made of two Y-shaped yokes (knuckles) connected by cross (spider)
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Cross-and-Roller Universal Joint
• Cross-and-roller joint or cardan universal joint – Most common type of drive shaft universal joint
• Bearing caps are held stationary in drive shaft yokes
• Roller bearings fit between caps and cross to reduce friction
• Cross is free to rotate inside caps and yokes
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Cross-and-Roller Universal Joint(Cont.)
(Chrysler)
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Constant Velocity Universal Joint
• Constant velocity universal joint or double-cardan joint– Two cross-and-roller joints connected by centering
socket and center yoke
• Two joints operate together on one end of drive shaft– Output shaft speed fluctuations are counteracted
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Constant Velocity Universal Joint(Cont.)
(Ford)
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Ball-and-Trunnion Universal Joint
• Ball-and-trunnion joint – Another joint designed for constant velocity
• Eliminates shaft speed fluctuations• Allows for slight length changes in driveline• Ball-and-trunnion joint seldom used
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Center Support Bearing
• Center support bearing – Holds middle of two-piece drive shaft
• Center bearing bolts to vehicle’s frame or underbody
• Supports center of drive shaft where two shafts come together
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Center Support Bearing(Cont.)
(Fiat)
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Driveline Types
• Hotchkiss driveline – Exposed drive shaft that operates rear axle
assembly mounted on springs – Usually has cross-and-roller universal joints
• Torque tube driveline – Solid steel drive shaft enclosed in large hollow tube – With independent rear suspension, drive shaft can
be one piece without universal joint
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Hotchkiss Driveline
(Ford)
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Transfer Cases
• Transfer case – Sends power to both front and rear axle assemblies
in four-wheel-drive vehicle
• Mounts behind and is driven by transmission• Two drive shafts normally run from transfer case,
one to each drive axle
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Transfer Cases (Cont.)
(Ford)
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Two-Wheel-Drive, High Range (2H)
• 2H range provided for normal driving when four-wheel-drive traction not needed
• Sliding clutch remains in neutral position • Torque is not transferred to front axle assembly
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Four-Wheel-Drive, High Range (4H)
• Sliding clutch is shifted into main shaft clutch gear • Torque then flows through drive chain, front output
yoke, and front drive axle assembly• Both front and rear axles drive vehicle
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Four-Wheel-Drive, Low Range (4L)
• Torque transfer is almost same as in 4H• Ring gear is shifted forward into lock plate• This holds ring gear stationary• Planet gears walk inside ring gear, producing gear
reduction
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All-Wheel Drive
• All-wheel drive – Four-wheel-drive system that does not use
conventional transfer case
• Designed for front-wheel-drive transaxle or transmission
• Transmission or transaxle in all-wheel-drive system is modified to allow power flow to front and rear drive axles
Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.
Drive Systems