APT - C2.pdf file for auto mechanics and

vehicle power train

1. Automotive Powertrain

Chapter Two
E. Drive Line

2. (cent) o

Front wheel drive : Rear wheel drive : Four wheel drive :

+ Flywheel + Flywheel + Flywheel

* Clutch + Clutch + Clutch

+ Gear box + Gear box + Gear box

+ Transaxle + Universal joint / slip joint + Transfer case

+ Drive shaft + Propeller shaft + Universal joint & Slip joint

+ Wheel + Final drive + Propeller shaft to front & rear
+ Differential + Final drive
+ Rear axle + Differential
+ Wheel + Front & Rear drive shaft

Tr: eae —__ "Wheel =
Differential E =

Transmission

Transfer Case

Rear
Drive Shatt

Front
Differential

Differential

3. ASE nes)
Forces and torques on the rear axle:

+ Side thrust

+ Weight of the Body
+ Braking Torque

+ Torque Reaction
+ Driving thrust

Weight of The Body:

+ Rear axle behaves like a beam supported at the ends
and loaded at two points.

+ The load coming on the axle is due to the weight of the
body being transmitted through the suspension springs.

+ Weight causes shear force and bending on the wheels.

4. Torque reaction:

+ From the Figure, it can be seen that the propeller shaft
applies the torque to the shaft D which is transmitted
through the bevel gearing E, is increased in the same ratio
as the speed is reduced.

The propeller shaft applies a torque to the differential crown
pinion shaft.

This torque is increased in the same ratio as the speed is
reduced by the final drive (within the differential assembly)
and is transmitted to the axle shafts which are connected
to the road wheels.

Now if the road wheels are fixed, the non turning the crown
pinion shaft, the pinion will have to roll round the bevel
wheel taking with it the axle casing. y M

pinion

smal gea

crown wheel 22

(=;

inner half

rotating cage

hice

3 shaft

outer half shaft

Automotive Engineering, FMIE, BIT

5. Cres vee ee)
+ There is a tendency for the same action to occur when the road wheels are being driven by the
pinion shaft.
+ This phenomenon shown in figure is called torque reaction.
+ The torque producing this action is the equal and opposite reaction to the driving torque which is
applied to the road wheels.
+ Some means must be introduced to prevent the axle casing from rotating in the opposite direction.

+ This may be simply the leaf springs themselves, or additional links — torque-reaction (Panhard
rods) or radius rods.

Nominal length

N = — Change in length
al Y Em =
Y

\ -Aceaeration and braking reaction force acting onthe spring haies
Change in propeller-shaft length
due to acceleration-torque reaction Fa- Driving force, F,- Reaction force, F»- Braking force,

Reaction Torque, Ts - Braking torque,

cceleration Torque

FMIE, BIT

6. Driving thrust:

The driving thrust, or tractive effort, of the road wheels is reacted by the
vehicle structure, the reaction being the inertia of the mass of the vehicle if it is
accelerating, or rolling resistance of the other axle plus the wind resistance if it
is not-the rolling resistance of the tires of the driving axle involves of course
purely local action and reaction.

In effect, therefore, the driving axle has to push the carriage unit along, so it
must be connected to the structure of the vehicle in such a way that this
forward thrust can be transmitted from one to the other.
This connection can be either the leaf springs or some other linkage for
locating the axle relative to the carriage unit. The relevant members of this
linkage are known as thrust members, or radius rods.
The driving torque produced in the engine is primarily responsible for
producing driving thrust in the rear road wheels. It has to be transferred from
the rear axle housing to the chassis frame which can be accomplished
through, either

+ Astrong rear springs,

+ Athrust-taking member such as radial rod.
When springs are used to serve this purpose, they are made strong enough in

FMIE, BIT

7. ee eee ees) o
Side Thrust: a

+ The rear axle is invariably subjected to side thrust(or pull), when the
rear wheels experience any side load. Such situation arises due to
cornering force when the vehicle is negotiating a curve, or when the
vehicle is moving over uneven ground.

+ To combat the side thrust and to hold the axle in its desired position,
the following provisions are generally made.

+ Taper roller or ball-thrust bearings are used for rear wheel, and
+ ‘Panhard rod’ is used between the axle casing and the frame.

Automotive Engineering, FMIE, BIT

8. Braking Torque:

The axle casing experiences the ‘brake torque’ when the brakes are
applied to the vehicle. The brake torque is produced in a direction

opposite to the torque-reaction, since the braking effect is reverse of
the driving effect.

Nominal length

2
Change in propeller-shaft ¿8 :
length due to brake-to a oe
reaction 33 -

FMIE, BIT

É

9. CEERERED Te)

The parts of Hotchkiss Drive are as follows:

The Hotchkiss drive is a well-established rear-wheel-drive drivetrain system utilized in the
automotive industry (commonly used in cars and trucks). It comprises a solid rear axle and leaf
spring suspension, offering a straightforward and cost-effective solution for many vehicles, from
passenger cars to trucks.

This configuration provides stability and durability, making it suitable for various applications.
The solid rear axle ensures that both rear wheels move together, enhancing traction and load-
bearing capacity. Leaf springs offer a flexible yet robust suspension system capable of handling
diverse road conditions.

Universal Joints — 2 No's etc
Propeller Shaft

Sliding Joint of Propeller shaft
Bevel Pinion Shaft

Rear Axle Casing

Wheel of the Vehicle

Leaf Spring

Frame Propeller Shaft — /
Shackle - 1 No's Universal Joint
Bracket - 1 No's

Sliding Joint ~ Spring

Wheel

10. (PUBIS reine of cerns)

joint Gear box Spring

shaft

joint

Bevel pinion shaft

The applications are:

Trucks and SUVs .
Off-road Vehicles

Vintage and Classic Cars
Heavy-duty Commercial Vehicles
Utility and Work Vehicles

Military Vehicles (Some Models)
Industrial Machinery (Limited Use)
Agricultural Equipment (Limited Use).

Power generated by the engine is transmitted through the gearbox
to the rear axle casing via a propeller shaft.

This shaft is positioned between two universal joints and a sliding
joint. In the case of the Hotchkiss drive system, the leaf springs bear
the entire vehicle load, including the body weight, driving thrust,
torque reaction, and side thrust.

The front half of the springs manages driving thrust and torque
reaction, causing deflection in response to these forces. The springs
also deflect in the opposite direction to accommodate braking
torque. This deflection impacts the position of the bevel pinion.

To prevent the propeller shaft from bending due to these reactions,
an additional universal joint is added to the end of the shaft.

The propeller shaft's length must vary accordingly as the rear axle
moves up and down in a circular motion centered on the front spring
support.

A sliding joint is incorporated into the propeller shaft to facilitate this
adjustment on uneven roads.

FMIE, BIT

11. | Advantages

Hotchkiss Drive is a straightforward and cost-
effective drivetrain system.

It is well-suited for off-road and heavy-duty vehicles

due to its robust design.

Easier maintenance and repair compared to more
complex drivetrains.

Can handle heavy loads and towing applications
effectively.

Suitable for various vehicle types, including trucks
and SUVs.

Often preferred in classic and vintage automobiles.
Generally more affordable to manufacture and
maintain.

Known for its longevity and reliability in demanding
conditions.

Disadvantage 2

Tends to exhibit more body roll and less precise
handling.

May provide a rougher ride on uneven terrain
compared to other systems.

Potentially lower traction in extreme off-road
conditions.

Can lead to a less balanced weight distribution
in some vehicles.

Typically not the choice for high-performance or
sports cars.

Less flexibility for advanced suspension setups.
May consume more interior space due to rear
axle placement.

Automotive Engineeı

, FMIE, BIT

12. (peta) -

+ Torque tube drive, also known as torque tube suspension, is a mechanical system utilized in the automotive
and aerospace industries to transmit torque or rotational force from the engine or power source to the
driven wheels or components.

+ This system uses a rigid, enclosed tube that houses and protects the driveshaft, providing a more stable
and efficient power transmission. Torque tube drive enhances vehicle performance and improves handling
and stability, making it a fundamental element in modern vehicle design and engineering.

+ It consists of a tubular member known as the torque tube that encases the propeller shaft and attaches to
the rear axle casing. The front end of this tube has a spherical shape, fitting into a cup secured to a cross
member of the vehicle's frame. The torque tube incorporates bearings to support the propeller shaft,
typically constructed from lightweight and torsional strong hollow steel tubing.

+ Suspension leaf springs connect to spring seats on the axle casing and are shackled at both ends to the
vehicle frame. This tubular member not only transmits thrust from the axle to the frame but also handles the
torque reaction, often assisted by radius rods to manage the twists and thrust generated by the vehicle's
drive. Gearbox

Shaft Cup Shackle Frame Shackle

Parts of Torque Tube Drive /

+ Torque Tube + Bevel Pinion Shaft

+ Shackle - 2 No's + Rear Axle Casing

+ Universal Joints — 1 No's « Wheel of the Vehicle

* Sliding Joint + Leaf Spring

Propeller Shaft Frame

~ Spring
Wheel

Automotive Engi

13. The various uses of Torque Tube Drive are:

Conventional passenger cars.

Light-duty trucks and vans.

Delivery vehicles.

Recreational vehicles (RVs).

Some classic and vintage automobiles.
Racing cars for improved drivetrain rigidity
and alignment.

Custom-built or speciality vehicles.

Light-duty commercial and industrial vehicles.

ON

A spherical cup is fixed to the vehicle's frame. One end of the
torque tube, featuring a spherical shape, is secured within the
cup. The other end of the torque tube is connected to the axle
casing.

The propeller shaft is enclosed within the torque tube.

The torque tube effectively absorbs the torque reaction.

This design ensures that the centerline of the bevel pinion shaft
remains constant and aligned with the center of the spherical
cup.

Suppose the propeller shaft is connected to the gearbox shaft
using a universal joint positioned at the center of the spherical
cup. In that case, there is no need for an additional universal
joint at the rear end of the propeller shaft.

Similarly, the absence of a sliding joint is possible because both
the propeller shaft and the pinion shaft pivot around the same
center, specifically the center of the spherical cup.

The torque tube efficiently manages both the torque reaction
and the driving thrust.

Automotive Engineeı FMIE, BIT W

14. ia Advantages

« Efficient torque transmission.

+ Improved alignment of drivetrain components.

+ Reduced need for additional universal joints.
« Enhanced stability and control.

+ Effective handling of torque reactions.

+ Suitable for light and medium-duty vehicles.
+ Simplicity in design and maintenance.

+ Minimized power loss during transmission

Automotive Engineeı

Disadvantage 2

Limited suitability for heavy-duty vehicles.
Reduced flexibility in suspension design.
Potentially complex repair and maintenance.
May transmit road vibrations and noise.
Limited adaptability to varying vehicle loads.
Higher manufacturing and installation
complexity.

Not ideal for off-road or rugged terrain use.

, FMIE, BIT

15. ESE) o

+ The propeller shaft transfers the power drive from the output shaft of the front body
mounted gearbox to the un-sprung rear axle final drive, so providing the means of
propelling the vehicle forward or in reverse.

+ The propeller shaft consists of a low carbon steel tube, either formed from rolled steel
sheet which is then butt welded along its seam or made from seamless drawn tubing.

* The hollow shaft ends are made a force fit over solid cylindrical recesses turned down on
both universal joint yoke bosses supporting the shaft, or alternatively between one
universal joint yoke boss and a sliding joint splined stub shaft.

+ The ends of the tube are then butt welded to the irrespective yoke boss or stub shaft
shoulder to make a rigid drive structure which is concentric to the input and output
support shafts.

+ The shaft is made hollow to apply its mass in the most effective position to resist twisting,

longitudinal sagging and rotational whirl. _
===

16. Midship Shaft

and Nut AF Snap Ring Style
Br [Axial Transmission
Case Slip Yoka

‘Companion Flange

or End Yoka 9 Standard or Self
Alighning
£ PEA Center Bearing À
Bearing Plate Style a
Universal Join E
ap Ring Style Iniversal
Joint and Quick Disconnect
AY Flange Yoka A Tube Shaft) Searing
¢ with Glidecode

Bearing Plate Slip
Yoka with Dust Cap

neering, FMIE, BIT By:T.W

17. There are two primary types of propeller shafts used in various
applications:

+ Single-Piece Type Propeller Shaft
+ Two-Piece Type Propeller Shaft

Single-Piece Type Propeller Shaft:

+ The single-piece type propeller shaft comprises two
universal joints, one slip spline joint, and one tubular shaft.
It is primarily employed for short-distance transmissions,
commonly found in cars and widely used in front-wheel
and four-wheel drive setups. This design offers superior
strength and durability, thanks to friction welding at the
junctions, ensuring a sturdy and long-lasting connection.

Automotive Engineering, FMIE, BIT

18. Neel cele)
Two-Piece Type Propeller Shaft:

+ The two-piece type propeller shaft features three universal
joints, one slip joint, and two tubular shafts.

+ This configuration is specifically suited for long-distance
transmissions, making it suitable for applications that
require power transmission over extended distances.

+ The strength factor is less due to the increased number of
joints. It is less durable as friction welding is not done. The
torque transmission is less than that of a single piece.

Automotive Engineering, FMIE, BIT

19. MIE o
+» Lightweight: The propeller shaft should be lightweight to contribute to the overall weight balance of the
vehicle, enhancing its efficiency and maneuverability.

+ Thermal Resistance: The selected material must exhibit excellent thermal resistance, maintaining
consistent physical properties even when exposed to elevated temperatures, ensuring long-term
reliability.

+ High Torsional Strength: The propeller shaft must possess high torsional strength to withstand and
endure demanding torque conditions without structural failure, ensuring a smooth power transmission.

+ Damping Quality: Considering the various dynamic variations and vibrations encountered during
operation, the propeller shaft should possess effective damping qualities to absorb and dampen
vibrations, promoting stability and reducing wear on the components.

+ Toughened and Hardened: Made from high-quality steel and induction hardened to ensure toughness
and rigidity.

+ Efficiently Combined: It should be firmly connected using a submerged carbon dioxide welding process
during operation.

20. + In vehicles, the engine position influences whether the front or rear wheels drive the vehicle. In
some vehicles, the engine is at the front, which results in front-wheel drive. On the contrary, in
some vehicles, the engine is at the rear, leading to the rear-wheel drive. For achieving rear-
wheel drive, every wheel is driven by a small propeller shaft.

« For ensuring proper functioning, the engine and transmission units are affixed to frame of the
vehicle frame with the use of flexible bearings. On the other hand, the rear axle, along with the
differential and wheels, connects to the vehicle frame through a suspension spring.

+ In this arrangement, the transmission output and input shaft within the rear axle housing lie in
different planes, necessitating the propeller shaft that links them to be inclined. As the rear
wheels encounter road unevenness, the rear axle moves up and down, causing the
suspension springs to compress and expand. Consequently, the angle between the
transmission output shaft and the propeller shaft changes.

+ Moreover, the length occupied by the propeller shaft also varies due to the rotational arcs of
both the propeller shaft and rear axle around the points of their axes of rotation. These
dynamic adjustments ensure the seamless transmission of power and enable the vehicle to
adapt to changing road conditions, providing a smooth and responsive driving experience.

W

Automotive Engineering, FMIE, BIT

21. Propeller shaft 0 Advantages

Low or No Power Losses: Propeller shafts facilitate efficient power transmission, resulting in
minimal or negligible power losses during the process, optimizing overall performance.
Lightweight Tubular Structure: The tubular design of the propeller shaft contributes to its
reduced weight, positively impacting the vehicle's overall weight distribution and fuel
efficiency.

Simple Construction: The propeller shaft's design is relatively straightforward, making it
easier to manufacture and maintain, ensuring cost-effectiveness.

Safe Power Transmission: With its sturdy construction and reliable materials, the propeller
shaft ensures secure and safe power transfer from the engine to the wheels, enhancing
driving stability.

Low Noise at High Torques: The well-engineered propeller shaft minimises noise
generation, even under high torque conditions, providing a smoother and quieter driving
experience.

Durability: Built from robust materials like high-quality steel, the propeller shaft exhibits
exceptional durability and resilience, withstanding challenging operating conditions.

Minimal Maintenance: Due to its sturdy construction and efficient power transmission, the
propeller shaft generally requires minimal maintenance, reducing downtime and associated
costs.

Automotive Engineering, FMIE, BIT w

22. ED) rn

Susceptible to High RPM Damage: Propeller shafts may be prone to damage if subjected to
excessively high RPM, leading to potential wear and tear.

Costly Hollow Propeller Shafts: The production of hollow propeller shafts can be costly,
adding to manufacturing expenses.

Limited Strength: Compared to other components, propeller shafts may have lower
strength, making them more susceptible to deformation or failure under certain conditions.
Vulnerability to Bending Forces: Propeller shafts may not be well-suited to handle significant
bending forces, which could result in structural issues over time.

Potential Oil Leakage at Spline: There could be a risk of oil leakage at the spline
connections, leading to lubrication problems and requiring maintenance.

Applications of Propeller Shafts

Constructional Motor Vehicles

Heavy-Duty Machines

Marine Vessels

Military Vehicles

Off-Highway Vehicles

Rail Vehicles

Industrial Machinery

, FMIE, BIT

23. + SM45C steel is a low-carbon, high-quality structural steel renowned for its excellent wear resistance, a
critical attribute for propeller shafts. This quenched and tempered steel exhibits a tensile strength greater
than 600MPa, ensuring robustness and durability.

+ Epoxy composite materials, particularly carbon epoxy composites, are also employed in crafting propeller
shafts. These composites boast a high tensile strength ranging from 800-1300 MPa, making them ideal
for manufacturing high-precision tubes.

+ Alloys of Aluminium and Stainless Steel: Propeller shafts can be crafted from various alloys of aluminium
and stainless steel due to their strength and ability to withstand torsional vibrations. Aluminium alloys, in
particular, exhibit high tensile strength, adding to their suitability for this application.

+ SAE1045 steel is another high-quality option with a tensile strength varying from 570-700MPa. Noted for
its excellent machinability and weldability, it finds widespread use in creating propeller shafts for diverse
automobiles.

+ Kevlar epoxy is an additional material choice for crafting propeller shafts, offering unique properties that
can contribute to the overall performance and strength of the shaft.

FMIE, BIT

24. + A universal joint is a connection between two objects, typically shafts,
that allows relative rotation in two axes. It is made up of two revolute
joints with perpendicular and intersecting axes.

+ Itis a joint or coupling connecting rigid rods whose axes are inclined to
each other and is commonly used in shafts that transmit rotary motion.
It consists of a pair of hinges located close together, oriented at 90° to
each other, and connected by a cross shaft. The universal joint is not a
constant-velocity joint.

+ When shafts are connected using a universal joint, each shaft
terminates in a revolute joint with its axis perpendicular to the shaft's
rotational axis. This allows rotary motion to be transferred between the
shafts while allowing misalignment in both remaining rotational
degrees of freedom.

+ Asingle rotational degree of freedom is constrained (the shaft rotation)
as well as all relative translations, giving a universal joint two degrees
of freedom (2-DOF).

+ The universal joint is not a constant-velocity joint. If the input shaft is
rotating at a constant velocity, the output shaft's velocity will oscillate.
They will have the same average velocity but the output shaft's velocity

will be somewhat higher or lower than this average at any given time.
Automotive Engineeı FMIE, BIT B W

25. ON

Universal joints allow drive shafts to move up and down with the
suspension while the shaft is moving so power can be transmitted
when the drive shaft isn’t in a straight line between the transmission
and drive wheels.

Rear-wheel-drive vehicles have universal joints (or U-joints) at both
ends of the drive shaft. U-joints connect to yokes that also allow drive
shafts to move fore and aft as vehicles go over bumps or dips in the
road, which effectively shortens or lengthens the shaft.

Front-drive vehicles also use two joints, called constant velocity (or
CV) joints, but they are a different kind that also compensates for
steering changes. On rear-drive vehicles, one sign of a worn U-join is a
“clank” sound when a drive gear is engaged.

On front-drive vehicles, CV joints often make a clicking noise when
they're worn. CV joints are covered by protective rubber boots, and if
the boots crack or are otherwise damaged, the CV joints will lose their
lubrication and be damaged by dirt and moisture.

FMIE, BIT

26. There are two types of universal joints, defined by their number of bending joints: Single joint D

+ Single joint: has only one bending aspect and is capable of operating at up to a 45-
degree angle.

+ Double joint: utilizes two bending joints, the double u-joint can operate at angles up
to 90 degrees. Additionally, it also accommodates parallel offset between 2 shafts
with an operating angle of the central section from 0 to 45 degrees.

+ Universal joints vary based on their material composition, hub type, and the applications
for which they are designed.
+ U-joints are available with two hub styles:

+ Solid: solid hub universal joints are solid and have not been machined, and as a
result, do not have a hole.

+ Bored: bored styles of u-joints generally derive their name from the shape of the
hole in their hub, as with round, hex or square styles.

+ Steel is the most common material used, either in stainless form; or alloyed with other
metals to handle greater torque and temperature.

+ Plastics and thermoplastics are often used in constructing universal joints, as this lends

ion resistance, as well as electrical and magnetic insulation in

Double joint

FMIE, BIT

27. WE) JA
15 Advantages Disadvantage

+ Universal coupling is more flexible than knuckle + Wear may occur if the joint is not properly

joint. lubricated.

* It facilitates torque transmission between shafts + Maintenance is often necessary to avoid wear.
which have angular misalignment. + Universal joint produces fluctuating motion

+ Itis cheap and cost-effective. + It does not support axial misalignment.

+ Itis simple to be assembled and dismantled.

+ Torque transmission efficiency is high. so SEELE OS

+ The joint permits angular displacements. 330

ao

Why two universal joints at the ends of a propeller shaft?

+ The out put shaft of a universal joint does not rotate with

uniform speed with in one revolution of the shaft when the
input speed is uniform.

+ The fluctuation in speed increases with increase in the
angle between the shafts. This effect can be cancelled out © |
by attaching one more u-joint whose input speed is ° „
fluctuating and output shat rotates with uniform speed. all

30 60, 90 120 150 180 210 240 270 300 330 360
, Input shaft angle (1 complete rotation)

W

FMIE, BIT

28. Inner CV Joint

Tis type of CU joint is used os the outer joint on most FL cars & minivans

ON

All modern cars with Front-wheel drive and all-wheel drive
with independent suspension have a special drive shaft that
connects the differential and wheel through Contact Velocity
Joint. This CV joint helps the driveshaft to transmit the
torque at an angle when a car takes turns or a sudden
bump comes on the road.

They provide the same output velocity in relation to the input
velocity that is independent of the angle at which the input
and output shafts operate. This contrasts with most other
joints such as Universal Joint, which may provide a different
output velocity at sharper angles even with the same input
velocity.

In this way, these side drive shafts help in transmitting
torque through an angle maintaining the same rotation
speed, and hence, ensuring a smooth ride of the vehicle.

Vehicles with front wheel drive require a special universal
joint to maintain torque at the wheel whilst turning a corner.
The joint is called a constant velocity joint.

FMIE, BIT W

29. al -

+ The constant velocity universal joint does not suffer from the
variation in the speed of the driven shaft. The speeds of the
shafts connected by this joint are absolutely equal.

+ Aconstant velocity universal joint consists of two yokes with
oval races, four driving balls, a center ball, a center ball pin

and retainer pin. The driving balls are freely mounted in the Thea
grooves. The center ball is secured on the pin in one of the (Ex) EA
yokes. In this unit, the balls are the driving contact. They En

move laterally as the joint rotates.

+ The movement of the balls permits the point of the driving
contact between the two halves of the coupling to remain in
a place which bisects the angle between the two shafts. =

+ By this arrangement, the fluctuation in speed of the driven
shaft is avoided.

193

FMIE, BIT

30. EEES on

+ The most common type of outboard CV joint is the "Rzeppa"
style. This type of joint was invented way back in 1920 by a
Dana engineer named Alfred H. Rzeppa. His design allowed
power to be transmitted through six spherical balls located mis type of cv joint is used as the outer joint on most FIJO cars & minivans
between an inner and outer race.

+ In this design, the balls are held in position by small
windows in a cage assembly that fits between the inner and
outer races. The design of the joint is such that the position
of the balls always bisects (cuts in half) the operating angle
of the joint. It is a slick design that works something like a
bevel gear. But instead of gear teeth transmitting the torque
across the joint, the balls push against their respective
tracks in the inner and outer housings.

Rzeppa tyle Constant Velocity Joint

31. A couple of variations on this design are the "double offset"
(DOJ) and "Plunging Disk Type Cross Groove" CV joints.
Both designs also have the six ball arrangement, but the
joints are used only on the inboard end of the shaft. Both
designs allow the inner race (which is mounted on the end
of the shaft) to "plunge" in and out so the shaft can change
length.

Why is this necessary? Because the shaft is usually longer
than the control arms on the suspension. The difference in
length would create interference problems every time the
suspension moved up or down.

So the plunging action of these joints allows the shaft to
slide in and out slightly to compensate for the difference.

Housing

Used as the inner joint on many import FWD cars & some GM cars

FMIE, BIT

32. ee) o

Cutaway view of Tripod “plunge” style CV joint

+ The other type of CV joint you will see is the "tripod" style Splined shaft “Spider”
joint. Tripod joints do not have balls but instead use needle totransmission
bearing rollers mounted on a three-legged spider. The ee =
rollers are mounted at 120 degrees to one another and slide — wheel

back and forth in tracks in an outer "tulip" housing.

+ Tripod style joints are used for the inner joints on most _4 LS
domestic and Asian FWD models from 1983 to present. This
type of joint is less expensive to manufacture than a ball
type joint, and is well-suited to the limited operating angles
of the inner joint location. The joint is designed to plunge in
and out the same as other inboard joints to allow changes in >
shaft length as the suspension moves.

FMIE, BIT

33. Front-wheel drive is the most commonly used drive principle
on passenger car models up to the mid-size class. Power is
transmitted via the front wheels.

The engine, transmission, axle drive and differential are
grouped together to form a compact unit. With front-wheel
drive, the car is pulled along, so that the drive forces and the
inertial force of the car are balanced.

The front wheels have to absorb drive, brake and cornering
forces. Influences on the steering are counteracted by
appropriate front suspension configurations.

This type of vehicle has a different setup compared to a
rear-wheel drive vehicle. The drivetrain components are
located at the front of the vehicle, so there is no need for a
long driveshaft. Instead, this type of vehicle uses special
joints called constant velocity (CV) joints to connect the
components.

Differential __—

Final Drive
Engine

Torque
Converter

A transaxle combines the transmission and
differential into one single.

FMIE, BIT

34. FWD vehicles are used for a few good reason, even though
it may seem that RWD vehicles are better overall. The main
reason is that they are cheaper for manufactures to
produce, thus offering a lower purchasing price for
consumers.

The engine, gearbox, steering, and other components are
all kept together at the front of the vehicle, which means it
can be created and fitted in the factory as a single unit. Less
work involved in manufacturing, and fewer parts needed in
its creation result in lower costs for everyone.

Another benefit to FWD vehicles is that they generally
handle better in adverse weather conditions. The reason for
this being that in the event you start to lose control in
rain/snow/ice, your vehicle will not violently swing to one
side or another. Rather, you will generally just go straight.
Also, when many people lose control they either tend to
push the brake or try to speed up.

Differential -

@Engine Final Drive

Min

O Front Wheel Drive Layout
Torque Converter

FMIE, BIT