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Chapter 12. Chapter 1. Drive Shaft Assembly Construction and Operation. Objectives. Explain the purpose of a drive shaft assembly. List the major parts of a typical drive shaft assembly. Explain the function and operation of a slip yoke. - PowerPoint PPT Presentation
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Permission granted to reproduce for educational use only.1© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.2© Goodheart-Willcox Co., Inc.
Chapter 1Drive Shaft Assembly
Construction and Operation
Chapter 12
Permission granted to reproduce for educational use only.3© Goodheart-Willcox Co., Inc.
Objectives
Explain the purpose of a drive shaft assembly.
List the major parts of a typical drive shaft assembly.
Explain the function and operation of a slip yoke.
Explain the function and operation of a universal joint.
Permission granted to reproduce for educational use only.4© Goodheart-Willcox Co., Inc.
Objectives
Name and describe different types of universal joints.Discuss Hotchkiss drive and torque-tube drive.Describe the function of a center support bearing in a two-piece drive shaft.Briefly explain the concept of drive shaft assembly angles.
Permission granted to reproduce for educational use only.5© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly
Drive shaft assembly (driveline) transfers power between transmission and rear axle assembly
Drive shaft assembly consists of:Slip yoke
Front universal joint
Drive shaft
Rear universal joint
Permission granted to reproduce for educational use only.6© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly (Cont.)
(General Motors)
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Drive Shaft Assembly (Cont.)
Slip yoke connects to transmission output shaft
Rear universal joint connects to differential through differential pinion yoke or flange
Balance weights reduce vibration
Permission granted to reproduce for educational use only.8© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly (Cont.)
(Ford)
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Drive Shaft Assembly (Cont.)
Drive shafts come in many sizes
Length is measured from center of each yoke hole on drive shaft ends
(General Motors)
Permission granted to reproduce for educational use only.10© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly (Cont.)
On late-model vehicles, front and rear axles move to keep chassis level
On rear-wheel drives, rear axle housing and both rear wheels move up and down in relation to chassis
Suspension system connects rear axle assembly to chassis
Permission granted to reproduce for educational use only.11© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly (Cont.)
Drive shaft angle and length must change to compensate for rear axle assembly movement
Flexible joints allow drive shaft assembly to flex or bend as rear axle assembly moves
Permission granted to reproduce for educational use only.12© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly Power Flow
Transmission to slip yoke
Slip yoke to front universal joint and into drive shaft
Drive shaft into rear universal joint
Rear universal joint into rear axle assembly
Permission granted to reproduce for educational use only.13© Goodheart-Willcox Co., Inc.
Drive Shaft
Drive shaft, or propeller shaft, is central part of drive shaft assembly
Universal joints and other parts are attached to it
Drive shaft consists of steel tube with yokes welded or pressed on each end
Shaft is balanced when manufactured
Permission granted to reproduce for educational use only.14© Goodheart-Willcox Co., Inc.
Slip Yoke
Slip yokeUsed where drive shaft assembly enters rear of transmission
Slides on transmission output shaft whenever rear axle assembly moves
(Ford)
Permission granted to reproduce for educational use only.15© Goodheart-Willcox Co., Inc.
Slip Yoke (Cont.)
Steel tube with yoke at one end
Yoke attaches to front universal joint
Internal part of tube is splined
May have damper (weight) to absorb vibration (Ford)
Permission granted to reproduce for educational use only.16© Goodheart-Willcox Co., Inc.
Universal Joints
Universal joints (U-joints) are swivel connections, or couplings, that allow drive shaft assembly to transmit power smoothly and constantly
Two basic types:Cross-and-roller
Constant-velocity
Permission granted to reproduce for educational use only.17© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints
Cross-and-roller U-jointUsed on most rear-wheel drives
Sometimes called Cardan U-joint or conventional U-joint
Permission granted to reproduce for educational use only.18© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints (Cont.)
Center cross (spider)
Four cups containing needle bearings
Cups are machined to fit into:
Drive shaft yokes
Slip yoke
Differential pinion yoke
Cup seals keep grease in cup and prevent entry of dirt and water
(General Motors)
Permission granted to reproduce for educational use only.19© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints (Cont.)
(General Motors)
Permission granted to reproduce for educational use only.20© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints (Cont.)
Some U-joints can be greased
Some U-joints are sealed at factory and cannot be greased unless disassembled
(Chrysler)
Permission granted to reproduce for educational use only.21© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints (Cont.)
Cups may be held in yokes in different ways
(Dana)
Permission granted to reproduce for educational use only.22© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints (Cont.)
Some vehicles use injected plastic to hold cups in place
(Dana)
Permission granted to reproduce for educational use only.23© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints (Cont.)
Larger vehicles may use more complex U-joints
(ArvinMeritor)
Permission granted to reproduce for educational use only.24© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints (Cont.)
Conventional U-joint is almost always driving at an angle, causing drive shaft speed to rise and fall twice for every revolution
Range of speed fluctuation increases as joint angle increases
Permission granted to reproduce for educational use only.25© Goodheart-Willcox Co., Inc.
Cross-and-Roller U-Joints (Cont.)
Fluctuation in drive shaft speedCreated at front U-jointCanceled at differential pinion yoke by rear U-joint
When equal angles are formed by U-joint at transmission and drive shaft and U-joint at drive shaft and rear axle
Canceled if U-joints are aligned in phase
Permission granted to reproduce for educational use only.26© Goodheart-Willcox Co., Inc.
CV Joints
Constant-velocity U-joints (CV joints)Provide extremely smooth power transfer
Are more complicated than conventional U-joints
Are used by larger rear-wheel drive vehicles to further reduce vibration
Permission granted to reproduce for educational use only.27© Goodheart-Willcox Co., Inc.
CV Joints (Cont.)
Double Cardan U-joint
Vibration forces are cancelled within center yoke
(General Motors)
Permission granted to reproduce for educational use only.28© Goodheart-Willcox Co., Inc.
CV Joints (Cont.)
Ball-and-trunnion U-jointNot used on modern vehicles
Separate slip yoke not needed
Permission granted to reproduce for educational use only.29© Goodheart-Willcox Co., Inc.
CV Joints (Cont.)
Rzeppa jointBall bearings held by slotted cross assemblyBall bearings move up and down on cross as torque is transmitted through themTransmits power through changing angles
(Dana)
Permission granted to reproduce for educational use only.30© Goodheart-Willcox Co., Inc.
CV Joints (Cont.)
Tripod jointResembles ball-and-trunnion U-joint, but uses three-pointed cross pin
Often used as inner bearing on front-wheel drives
Sometimes used on drive axles of rear-wheel drives with independent rear suspension
Permission granted to reproduce for educational use only.31© Goodheart-Willcox Co., Inc.
Differential Pinion Yoke
Differential pinion yokeConnects to drive pinion gear in rear axle assembly
Has internal splines that fit external splines on drive pinion gear shaft
Held to shaft by large locknut
Permission granted to reproduce for educational use only.32© Goodheart-Willcox Co., Inc.
Differential Pinion Yoke (Cont.)
Differential pinion flange, or companion flange
Two-piece yoke joined by mating flanges
One flange holds rear U-joint, other connects to pinion gear
(Ford)
Permission granted to reproduce for educational use only.33© Goodheart-Willcox Co., Inc.
Classes of Drive Shaft Assemblies
Hotchkiss driveUsed almost exclusively in late-model, rear-wheel vehicles
Torque-tube driveUsed on some makes of vehicles for many years, but now uncommon
Permission granted to reproduce for educational use only.34© Goodheart-Willcox Co., Inc.
Hotchkiss Drive
Hotchkiss driveUsed with rear leaf springs
Salsbury driveUsed with coil springs
(Fiat)
Permission granted to reproduce for educational use only.35© Goodheart-Willcox Co., Inc.
Hotchkiss Drive (Cont.)
Variation of Hotchkiss drive:Constant-velocity U-joint is usedSlip yoke is at rear of shaftOne spline is larger than others
(Ford)
Permission granted to reproduce for educational use only.36© Goodheart-Willcox Co., Inc.
Torque-Tube Drive
Torque-tube drive is designed to control rear-end torque
Drive shaft connects to transmission output shaft through U-joint
Other end of shaft connects to drive pinion gear through coupling or splined connection
U-joint at only one end
Permission granted to reproduce for educational use only.37© Goodheart-Willcox Co., Inc.
Torque-Tube Drive (Cont.)
Drive shaft assembly can flex only at U-joint between transmission and drive shaft
Rear axle assembly moves up and down in arc as it pivots about U-joint
Distance between transmission and rear axle assembly is always the same, so no slip yoke is needed
Permission granted to reproduce for educational use only.38© Goodheart-Willcox Co., Inc.
Two-Piece Drive Shaft
Two-piece drive shaft Two drive shafts• Steel tubes with yokes on all four ends
Three universal joints• Identical to those on one-piece drive shaft
Drive shaft assembly angles are reduced at each U-joint, reducing vibration
Permission granted to reproduce for educational use only.39© Goodheart-Willcox Co., Inc.
Two-Piece Drive Shaft (Cont.)
Permission granted to reproduce for educational use only.40© Goodheart-Willcox Co., Inc.
Two-Piece Drive Shaft (Cont.)
Center support bearing keeps drive shafts aligned
Slip yoke usually installed behind support bearing
Some designs have two slip yokes
(Fiat)
Permission granted to reproduce for educational use only.41© Goodheart-Willcox Co., Inc.
Two-Piece Drive Shaft (Cont.)
Two-piece drive shafts:Were used when vehicle frame design prevented use of single drive shaft
Were discontinued during 60s and 70s except on large trucks and some long-bed pickups
Became common again with increased popularity of large SUVs
Permission granted to reproduce for educational use only.42© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly Angles
All rotating parts have axial centerline, or rotational axis
When rotating parts are coupled together, centerlines must be closely matched
Permission granted to reproduce for educational use only.43© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly Angles (Cont.)
Perfect alignment is seldom achieved
Permission granted to reproduce for educational use only.44© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly Angles (Cont.)
Drive shaft assembly angle (also called operating angle or U-joint angle)
Permission granted to reproduce for educational use only.45© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly Angles (Cont.)
On front-engine, rear-wheel drive vehicles, drive shaft assembly angle exists between centerlines of:
Transmission output shaft and drive shaft
Drive shaft and drive pinion gear shaft
Permission granted to reproduce for educational use only.46© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly Angles (Cont.)
Angles are measured at front and rear U-joints
Manufacturer’s specification is usually about 1° or 2°
If angle is greater than specified:Speed fluctuations of shaft tube increase
Shaft may have objectionable vibration
Joint can break
Permission granted to reproduce for educational use only.47© Goodheart-Willcox Co., Inc.
Drive Shaft Assembly Angles (Cont.)
Angles are affected by:Added weight to vehicle
Road surface condition
Vehicle acceleration or deceleration
Suspension system wear or alterations
Original angles must be kept as close as possible to specifications
Permission granted to reproduce for educational use only.48© Goodheart-Willcox Co., Inc.
Review Questions
To compensate for rear axle movement, the driveshaft ___ and ___ must change.
Answer: angle, length
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Review Questions
The ___ slides on the transmission output shaft whenever the rear assembly moves.
Answer: slip yoke
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Review Questions
True or False? A slip yoke has external splines.
Answer: False. A slip yoke has internal splines.
Permission granted to reproduce for educational use only.51© Goodheart-Willcox Co., Inc.
Review Questions
A swivel connection, or coupling, that allows the drive shaft assembly to transmit power smoothly is called a(n) ___.
Answer: universal joint
Permission granted to reproduce for educational use only.52© Goodheart-Willcox Co., Inc.
Review Questions
From the slip yoke, power flows into the ___ and then into the drive shaft.
Answer: front universal joint
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Review Questions
A double Cardan U-joint is composed of two cross-and-roller U-joints connected by a(n) ___.
Answer: center yoke
Permission granted to reproduce for educational use only.54© Goodheart-Willcox Co., Inc.
Review Questions
A cross-and-roller U-joint is sometimes called a ___.
A. Cardan U-joint
B. conventional U-joint
C. double Cardan U-joint
D. Both A and B.
Answer: D. Both A and B.
Permission granted to reproduce for educational use only.55© Goodheart-Willcox Co., Inc.
Review Questions
True or False? The Hotchkiss drive is the most common type of drive shaft assembly.
Answer: True
Permission granted to reproduce for educational use only.56© Goodheart-Willcox Co., Inc.
Review Questions
In a two-piece drive shaft, the ___ keeps the drive shafts aligned.
Answer: center support bearing
Permission granted to reproduce for educational use only.57© Goodheart-Willcox Co., Inc.
Review Questions
Driveshaft assembly angles are measured at the front and rear ___.
Answer: U-joints