Evaluation of Length Prof R N Patil

EVALUATION

Mrs Archana
I Research

OF LENGTH

S.Chavan

Scholar

OF PROPELLER

Mr.Chavan

I

2

S. S2.

Research Scholar

SHAFT

Prof. Patil R N3.
3

Assistant Professor

Department Of Mechanical Engineering Bharati Yidyapeeth University, College of Engineering,
Dhankawadi, Pune-43. Ph. [0] (020) 24371378 exrn. 298 [M] 9226794076 Fax: (020) 24372998
E-mail: -sachin77887(aJ.rediffmail.com

Abstract
The power from Transmission shaft should be transmitted to the Rear axle of the vehicle. The axis
of the Transmission and the connecting member of Rear axle are at an angle, which changes with the
variation in load or the road condition. To facilitate the power transmission at a variable angle a Propeller
shaft is used. With respect to the geometrical construction the Propeller shafts are categorized into single
piece two-piece and three-piece propeller shafts.
In case of two or multi stage propeller shaft length of the rear propeller shaft is subjected to
variation while the remaining propeller shafts are rigid members; i.e. do not change in length. The variation
in the length of rear propeller shaft is allowed using a splined shaft. Generally length of the propeller shaft
is decided after freezing the remaining aggregates. It is assumed that the inclination of cross member
bracket (in case of multistage propeller shaft) is also decided based on the requirement criteria such as beta
equivalent angle. The maximum and minimum length of the propeller shaft required is found in this paper
there by finding the slip required for the particular vehicle. The main objective of the paper is to find the
length of the propeller sha ft.
A Microsoft Excel program is made which reveals the calculation. Hence, if a parameter is
changed, its effect in the other output values can be easily seen.

Keywords:

Propeller Shaft, Splined Shaft, Universal Joint,

1. INTRODUCTION
Where the engine and axles are separated
from each other, as on four-wheel-drive and rearwheel-drive vehicles, it is the propeller shaft that
serves to transmit the drive force generated by
the engine to the axles. For its usage, the optimal
shaft is a short, bar-like product. The longer the
bar, the more liable it is to sag and sagging is
further promoted when rotation is applied.
Sagging causes vibration and results in an
increase in noise, to such an extent that the shaft
is likely to break when the critical speed is
exceeded. The propeller
shaft is naturally
designed not to break when used within the
service limits expected of use. In addition. it is
is subjected to variation while the remaining
propeller shafts are rigid members; i.e. do not

designed to suppress vibrations arising from a
wide range of causes [I].
Defining the length of the propeller shaft
is an important task in the production of any
vehicle. The power is transmitted from Gearbox
to differential by means of propeller shaft.
Depending on the length of the vehicle there is a
necessity to make the propeller shaft in stages.
The orientation of the propeller shaft is a critical
factor defining the length of the propeller shaft.
In case of multistage propeller
shaft the
intermittent pieces are supported by center
bearings. which are mounted on the bracket of
cross member [2]. In case of two or multi stage
propeller shaft length of the rear propeller shaft
change in length. The variation in the length of
rear propeller shaft is allowed using a splined
shaft [I].

Where the engine and axles are separated
from each other, as on four-wheel-drive and rearwheel-drive vehicles, it is the propeller shaft that
serves to transmit the drive force generated by
the engine to the axles.
The basic function of a driveshaft is to
transmit power from one point to another in a
smooth and continuous action. In automobiles.
trucks and construction equipment the drive train
is designed to send torque through an angle from
the transmission
to the axle (or auxiliary
transmission).
The driveshaft
must
operate
through
constantly changing relative angJes between the
transmission and axle. It must also be capable of
changing length while transmitting torque. The
axle of a vehicle is not attached directly to the
frame, but rides suspended by springs in an
irregular, floating motion.
This means the driveshaft must be able to
contract. expand and change operating angles
when going over bumps or depressions. This is
accomplished through universal joints. which
permit the driveshaft to operate at different
angles, and slip joints which permit contraction
or expansion to take place [4]. Fig. 1 shows the
Schematic representation
of vehicle.

r>

Fig. 1 Schematic

Representation

2. TYPES OF PROPELLER

SHAFT 13)

2.1 Single piece propeller shaft
Vehicle models: - This type is used in
vehicles with a short distance between the
engine and axles, MR base four-wheel-drive
vehicles.
Characteristics:
- The friction welding
adopted at the junction has contributed to an
improvement in the strength, quality, and
durability
of
the
junction.
- A reduction in the number of component
parts and in the weight has been achieved.

_Fig. 2 Single piece type propeller shaft
(Courtesy)
2.2 Two piece Propeller shaft
Vehicle models: - This type is used in vehicles
with a long distance between the engine and
axles, Front engine front drive base four-wheeldrive
vehicles,
and
the
like.
Characteristics:
- The division of the propeller
shaft into two parts has allowed the critical speed
to be prevented from falling and the vibration
problem from occurring, which would otherwise
be the case when the overall length of the shaft is
increased.

of vehicle

To fmd the length of the propeller shaft
thereby finding the slip required
for the
particular vehicle in,
Bump condition ,Rebound condition. Flat
condition.
The inputs parameters of the program are as.
Engine block, Gear Box housing, Frame,
Rear axle Rear suspension, Propeller shaft.
The output parameters of the program are as,
Maximum length of the propeller shaft.
Minimum length of the propeller shaft.

Fig. 3 Two piece type propeller

shaft

(CourtesY)
- The dynamic damper inserted into the pipe
reduces
the
vibration
and
noise.

- A reduction in the number of component
parts and in the weight has been achieved.
-Two piece drive lines, with two propeller'
shafts and an intermediate
support bearing
Shown in fig. 3 are generally used on trucks
with wheel bases from 3.4 to 4.8m.
2.3 Three piece propeller
shaft
For vehicles more than 4.8m wheel bases, a
three piece drive line with two intermediate
support bearings may be necessary as shown
in fig. 4.

Fig. 4 Three

piece type propeller

3. EVALUATJON

shaft

METHOD

3.1 MECHANJSM
AFFECTJ
G
PROPELLER
SHAFT LE GTH
Different mechanisms
that affect the length of
the propeller shaft are found to be
I. Axle path of the rear suspension system
2. Static brake windup
I. Axle path of rear suspension
system
The length of the propeller shaft attains
the extreme conditions because of the motion of
the suspension system. The path traced by the
axle is identified and at each configuration
lenzth
of the propeller
shaft is foun-d. Differe;ce
between the maximum
and minimum
lengths
gives the slip that should be allowed.
As the spring leaves of constant cross
section
properly
stepped
to approach
the
condition of uniform strength is deflected, it will
assume the shape of circular arc at all loads
between zero and maximum load, provided it has
a circular arc shape or is flat at no load or at anv
given load.
•
It is observed that most of the springs
approximate these conditions closely enough so
that the circular arc shape can be used to
calculate their geometric
properties.
A set of
procedure is used to reproduce the path traced by
the bottom of the spring with an accuracy of 1%.

When flexibility or deflection in a
system is specifically desired. some
spring can be used. Otherwise
deformation of an engineering body
disadvantage.

mechanical
form of the
the elastic
is usually a

Spring:
Spring part made in a particular configuration to
provide a range of forces over a significant
deflection or to store potential energy.
Springs are employed to exert forces or
torques in a mechanism or to absorb the energy
of suddenl_ applied loads. Springs frequently
operate with high values of working stresses and
with loads which are continuously
varying.
Helical and leaf springs are in widest use. The
springs take care of two fundamental
vertical
actions: jounce & rebound. [ I I]
JOUNCE
(Bump) occurs when the wheel hits a
bump & moves up. It is upward displacement of
wheel relative to the car bodv. When this
happens. the suspension systems -acts to pull in
the top of the wheel, maintaining
an equal
distance
between
the two front wheels &
preventing a sideways scrubbing action as the
wheel moves up and down. Road bumps or
speed breakers function as speed reducing by
inducing jerks & vertical acceleration. The driver
knov s that higher the speed. the greater the
discomfort S: forces on the 'vehicle. The degree
of comfort varies with the bump profile, height
gradient, length & vehicle parameters. (12]
REBOUND
(Droop) occurs when the wheel hits
a dip or hole and moves downwards.
It is
downward displacement
of wheel relative to the
car body. In this case. the suspension system acts
to move the wheel in at both the top and bottom
equally, while maintaining
an equal distance
between the wheels.
The spring goes back & forth from jounce to
rebound. Each time, jounce & rebound become
smaller &smaller. This is caused by the systems
molecular
structure
and the suspension
pivot
joints.
A shock absorber
is added to each
suspension to dampen and stop the motion of
spring after each jounce.
Cantilever
Spring
For a spring of this type the center of
the eye of the Berlin type moves in a path with
radius of 0.751 central to the main leaf: I being
the front length minus the inactive length on
front spring. If a distance 'e from centers-of the
main leaf offsets the eye center. the center of arc
will be offset by 0.5e in the opposite direction.
This construction
reproduces the change of arc

height with an accuracy

of I% up deflection of

0.6\.

Two Point Deflecrion Method POJ
This method is used for construction of the axle
path of circular spring. It has the advantage that
all of the layout work can be done within the overall
length of the spring. In cases where the unsymmetry
factor is small and the 0 point is far from the axle
center, it is the only known procedure which
permits construction within the confmes of the
standard layout board and straight edge.
The principle of this method is based upon the
use of the two cantilever deflections corresponding
to a given deflection at the center of the spring seat.
These deflections may be computed for two vertical
positions of the spring seat, for example maximum
compression
(metal-to-metal)
and
maximum
rebound. When they are applied to the three-link
equivalent of the spring with the main leaf in the flat
position, the path of the axle and the angles of the
spring seat can be determined entirely by
construction.
4. METHODOLOGY

-. -.

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I

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I

I
I

;L1

I

L2

:P'

fo i .
----+.

; ; ; e2
--+;;

i

L3
I

I
Y

L4! L5
It

r

"""7

i
Y

~

el
Fig. 5 Ray Diagram

of propeller

shaft

The Location hole is taken as a reference
along the length of the vehicle. The top of the
frame is the reference for vertical axis. The
coordinates of the point is located using the
dimensions of different aggregates. The end of
prop2 connected to differential is the critical
point deciding the length of the propeller shaft.
To locate the point the input can be the
inclination of spring stack with the vertical and
the distance of bottom of spring from the top of

the long member. The other dimensions are
given with respect to the bottom of the spring.
Based on geometry "the position of end of prop2
can be found. In case of bump and rebound
condition the axle path curve is used to locate the
point. The distance between the two ends of the
prop2 is the length of the prop shaft
5. J PlJTS TO THE PROGRAM I) I
The basic components that affect the length of
the propeller shaft are identified to be:
I. Engine block
2. Gear Box housing
3. Frame
4. Rear axle
5. Rear suspension
6. Propeller shaft
The coordinate system:
The top of the frame, centerline of location hole
and vehicle centerline are considered as the three
coordinated of the body of the vehicle. In input.
the locations
of different
components
are
referred with respect to this coordinate system.
1. Engine Block
I. The inclination of the engine with
respect to the top of the frame in
clockwise direction.
2. The distance between the centerline of
the engine and the rear face of the
engine block
3. The distance of the crankshaft of the
engine from top of the engine at the
centerline of engine.
4. Distance between the centerline of
location hole and center line of engine
block
5. Length of flywheel housing
2. Transmission
I. The length of clutch housing between
the flywheel and gear box
2. The length of gear box housing from the
clutch face to the flange face
3. Frame
I. Distance between the centerline of front
axle and the centerline of location hole
2. Distance of Cross member from center
line of location hole along top of the
frame
3. Inclination of cross member on the
frame with respect to the vehicle
coordinates in anticlockwise direction
4. X coordinate of the Eye I of the rear
leaf spring
5. Y coordinate of the Eye
of the rear
leafspring

6.

X coordinate of pivot of shackle of rear
leaf spring on frame from center line of
location hole
7. Y coordinate of pivot of shackle of rear
leaf spring on frame from the top of the
frame
4. Rear axle
I. Distance between the axle of the crown
wheel and pinion in side view
2. Distance between the axle of the crown
wheel and pinion in plan
3. Distance of spring bottom to the axle
center
4. Distance of axle center to the flange
face on the pinion connected to the
propeller shaft
5. Inclination of mounting face of the rear
axle suspension
with X axis in
clockwise direction
5. Rear Suspension
I. Span of the spring III flat spring
condition
2. Length of the shackle of rear suspension
3. Stack height of the main spring in
suspension system
4. Diameter of eye of the spring
6. Propeller Shaft
../

Single piece propeller

6. PROGRAM FOR LENGTH
6.] Program Input

I.

Distance between
UJ cross center
../

I.
2.
3.
4.

5.

I.

flange face and the

Two piece propeller

shaft

Distance between flange face and the
UJ cross center
Inclination of cross member bracket on
the frame
Distance of axis of center bearing to the
mounting bracket face
Distance between center bearing and
flange face along the axis of propeller
shaft
Center bearing offset at the cross
member along x axis
../ Three piece propeller shaft
The corresponding inputs for second
cross member need to be given as input.

shaft

CALCULA TlON

Vehicle 1PROGRAM TO CALCULATE

THE LENGTH OF PROPELLER

SHAFT (2PIECE)

INPUT

FRAME

ENG.
MTG.

GEAR
BOX
PROP.SH.

X coordinate of CL of Location hole

XI

0

X Coordinate of CL of front axle from CL of location hole (abs value)

e2

25

X coordinate of Eye I of Lf spring from CL of location hole

Xl

Y coordinate of Eye Iof Lf spring from top of frame
X coordinate of shackle pivot of Lf spring on frame from CL of location
hole

YI

2410
]3].5

X2

Y coordinate of shackle pivot of Lf spring on frame from top of frame

Y2

Angle of inclination of Engine with the X axis(in degrees)

Tl

2

X Coordinate of CL of Engine from CL of location hole (abs value)

el

Y coordinate of CL of Engine from frame top face

L7

70
]85

Distance between CL of the Engine to the RFOB

Ll

375

Length of Flywheel Housing (RFOB TO RFOFH)

L2

134.1

Length of Clutch Housing (RFOFH TO RFOCH)

L3

]76

Length of Gear Box (RFOCH TO GB Flange face)

L4

596

Distance from Prop. Shaft Flange face to Center of Yoke

L5

83.3

3980
131.5

REAR
AXLE

SUSP.

r

Distance between the center of the rear axle and the flange face (in Z
direction)
Distance between the center line of rear axle and the flange face center
(in y direction)

zl

40

Distance of spring bottom to the axle center

ra

88.5

Distance from center of Rear axle to the flange face

zO

Inclination of mounting face of rear axle (along x axis)

T5

388
1.75

Lxz

45

Length of shackle of rear spring

P2

]00

Length of Main leaf of leaf spring

P3

]600

Stack height of rear spring ( Main spring)

Hs

196

Diameter of eye of spring

De

30

OUTPUT
Distance between the CL of Engine and the CL
of front axle
Angle of inclination of Engine with the X
axis(in radians)
Inclination of mounting face of rear axle( In
radians)
Total Length between CL of front axle (0) and
GB flange yoke center (B)
Coordinates of 0
Coordinates of B
Distance between two pivots of the spring
Inclination of spring with the line joining
pivotes on the frame
Angle between two pivotes on frame with
respect to top of the frame
Inclination of spring with the vertical axis ( Y
axis)
X coordinate of Center of main spring leaf (from
front axle)
Y coordinate of Center of main spring leaf (from
front axle)
X coordinate of bottom of spring/rear axle
center
Y coordinate of bottom of spring/rear ax Ie
center
Distance of rear axle center from top of the
frameiby program)
Length of differential housing from center of
axle to the yoke
Inclination of rear axle center with respect to x
axis
Distance between the bottom of spring and the
pinion connected to the propeller shaft

e

45

TI in radians

0.034906585

T5 r

0.030543262

OB

1319.372571

o (x, v. z)

0
1318.568844

B(x,y,z)
PI
P4

186.57143
232.61687

1570
32.84375

ALFAI

0.060197223

3.4490468

T3a

0

0

Ts

0.060197223

Xr

3233.550955

Yr

] 79.6286984

Xb

3220.8570 I I

Yb
Hsl

390.2465129
211

L8

438

z3

471.3

T3

1.699046791

z l+ra
z2

128.5
114.5199903
3.395473595
471.5072965

z4
z5

0.029654

Distance between rear axle and center of the
yoke along x axis
X coordinate of 0
Y coordinate of 0
Z coordinate of 0
X offset of bottom of spring and the center of
yoke of propeller shaft
Y offset of bottom of spring and the center of
yoke of propeller shaft
Coordinates of 0
Length of propeller shaft 2 (yoke to yoke)

DE-x

Dz

474.9027701
2745.954241
504.7161549
45

DBsx

474.9027701

Dbsy

114.469642

Ox
Dy

o (x, v, z)

2745.95424 I
1453.785435

504.71615

7. RESULT

RESULT
Length of propeller shaft 2 ( from flange end to
the flange end)-FLAT SPRING CONDITION

Minimum length of propeller shaft 2
Maximum length of propeller shaft 2
Slip required for propeller shaft spline shaft

Inclination of shackle with the s
Inclination of shackle with the s

Prop2

I 1620.385435

I

2403.42849 I
2500.387487
96.95899546

1.536835
88.05416

8. CONCLUSIO
The maximum and minimum length of
the propeller shaft required is found in this paper
there by finding the slip required for the
particular vehicle. A Microsoft Excel program is
made which reveals the calculation. Hence, if a
parameter is changed. its effect in the other
output values can be easily seen.
9. REFERE 'CES
I). H. I. F. Evernden, "The Propeller Shaft or
Hooke's Coupling and the
Cardan Joint, ..
Proceedings of the Institution of Mechanical
Engineers.
October, 1949. PP. 5-6.
2). Thomas. D. Gillespie. 1994. Fundamentals of
Vehicle Dynamics, PP. 24.

3).http://v,,\w.showa/
.com/enJProducts/4rs/Propeller.

S. html.

4). Wagner. E. R. "Driveline and Driveshaft
Arrangements and
Constructions, "Universal
Joint and Driveshaft Design Manual, Chapter
J, SAEAE-7. 1947,PP.440.
5). P. J. Mazziotti, "Universal Joint and Propeller
Shaft. "Dana Corporation
Bulletin J-1371,
October 15, 1954.
6). B. R. Reimer. Design and Application
Considerations for Agricultural PTO Drivelines,
SAE Paper 650680, 1965.
7).
http://w\vw.tpub.Com!Content!
constructionlI4273/
css / 14273
182. html.
8). Welded steel Tube Institute, Handbook of
Welded Steel Tubing, 1967.
9). L. J. DiFrancesco, Better Needle Bearings for
Universal Joints, SAE
Paper 660159, 1966.
10). Spring Design Manual. A E-21.
1I). John C Dixon. Tires, Suspension
&
handeling.
12). Gawde, Mukherjee. Mohan. Sept 2004 .
Wheel lift-off &ride comfort of three wheeled
vehicle over bump. IE (I) Journal-MC.PP 78-87.