at 2352 chassis components design university qp

7/25/2019 AT 2352 Chassis components design University QP

1/14

.

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ll'Il"rD.Tech'

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tor:robile

Engin+ering

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I

3 S

1

_*

hUTO

IvIOTIVE

Ct{"AriSIS

D

i1:$

if.t

},1

(Regulat.iou

2004)

Tirne

:

Three

hours

fi'lttximur;:

: 100

:narlis

Answctr

ALL

guestions.

PART

r\'

(10

x

2

=

2A

rnarlis)

1.

.

$/[r:rt.

hsppens

if.ii:e

cillrnrete,

of

thc

driven plate

is

i,cr.ee.scd'l

Z.

Why

is

'

cone

cltrtch

,r,oro

ofto.ti.rc than

piate

clulch

?

;r.

3.

lVhat

is the

conditiori

for

maximunr

tracLiorr.l

z'

t

4.

Ho.r

are

intermcdiate

gears

decidcd?

6.

Wh.st

ure

thc loadg

and strcsscs

ihe

franrc,

hns

to

rvithsfand?

6.

,

what

is

the

eliect

ola

camber

ect

give'

to

cnch

rcaf-springl

7

.

Wrut,

a.ra

the

type

of strcsses

encountod by

fronl

*rJci.

B.

lYJrat

are

nra-in

causcrccd

r1{rrltion

o.

r"un*u.

?op

5.1

,r,

ir*t*r=1ll]':f",r-ii

to

pro'iclr

t}re

ill

f

i,l"'-1;i;

i,

Xll,:

ff

i'

i'J'

*

rc

d

uc

ri

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;;

fi

ilf

LI;

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-

lli,:

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lY i",,,,,J.,il:

ffi

:illH

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{1,)

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i

sl.

-s

$

t,l

lc

ci

es

iilrr

grrrrce,

l

r-r:.+

r'a""n,

a,,,

r.,-,,,,,.,,,

rr:ru'

lrrlarinl;r;

of

rr

4

rspeccl

gcnr

l;ox,

r,rbcn

2iiri

1?

(a)

calctrlatc

lhq

maxmum

be'ding

*roraent,

&i:d

rnorimu::i

section

rnodulus

ssuming

thc

follorving

particrrllr:.

\\tcel

base

=

lBC

cm

:

Ovcrall

length

=

860.

cm

[:,1ual

ovcr.liang

on

aither

nide.

2',l00

N

acti,g

ar

c'G'

of

load

45

cr'in

froul

or.front

r*ci.

1BC,

N.

^cLinJ;

at

C..G

of

load

46

cnr

U",,,,,,

,.ru,;;;;;;

I800

N

acling

ie

c.'c

of

lo*d

45 crn

in front

c,f

rc&r

*vJs,

6?5

I{

ncting

;,,"'i.-:.(}

ol.loacl

45 cm

Lrehilri

tlc

rerrr

ax,lc.

::;f

i::?f:l;;:i:jl:'J,,,

die,-ribured

road

or

1.75

Nlnrin

r,,

ov*

rhc

Anrrrnrrr

rjynanric

o[rcss

ie

l,u,ice

l,irc

st-a.Lic

sLrcas

inclur:ed.

i"acl.,

ori

flr-ont.

rlnrl

g;eni'

is

in

cngrrgenieat.

Or'

C

BOOB


10/14

"

r$

B

E

,:

':,

11,

.1;

'l

h)

,z{tnrsion

-

bar suspension

is to be

dcsigued

to

support

a

rnaximum

static

/

Ioad

of

B4S3.S

N

at

the

end

of

a

lever

arm

250

nlm

long.

'Ihe

deflection

of

the

lever

above

the

horizontal

is

to

be

30'rvith

a

total

angle

ofdeflection

of

90o.

Assuming

a

safe

nllowable

stress

of

?84800

liPa,

cillculate

(r)

The

diameter

of

torsion

bar

(ii)

1'he

effective

iength

and

(iii)

Thc load rate.

The

load

distribution

between

the

front

and

the

near

a-de

of a

moi'or

vehicle

rveighing

1450

kgs

is

tbat

46?o of

thc

total load is

taken

by

the

front

axle.

The

viidth

of the

track

is

140

cm

and

the

distance

betrveen

the

ccntres of

the

spring

pads

is

66

cm.

Design

a suitable

I-Seqgion

for

[ re

froni

axle

assuming

that

the

rvidth of the

flange

and

its thiclcness

are

Q.6

and

0.2

of the

o'rerall

depth

of

the

section

respcctivcly

and

thc

tirickness

of

the

rveb

0.25

of

width

of the

{lange

. Assume

a

worldng

strcss

of 915

kgflcm2.

t:

.

l,'

.

ir:

,i.

f.

r.;

;r

i?--

axlc

'ot

\.,

r

ehaft

ie Lo be deeigned

for

a full floating

ncsr

o'xlc.

Givcn:

Maximum

cngine

Lorque

=

Rear

axlc

ratio =

190

Nrrr

5:l

4:1,2,5;L,1.4:1

ear

ratios

Pcrnriasible

ahoar

stregs for

axlo

ghafL

mstcrial

is

Calculal.e

the

dismetsr

of

tlro

uxle shaft.

and

1:1

13734 N/rn2.

XloT

/,

.,/

t

li

l"

r4?).d

,/

Or

,/G

f6

'

X cary

has

pivot.

pins

f

.Ia

m

apart,

l.he

lcngth;pf

euch

trtrclc

itrttrs

'is

O.f6IO

m

and

the

trick

rod

behind the

axlo

is

1.64

ru long.

I)ctc::mi:ic

'

the

whcelbgso

for

true

rolling

of all

wheels

when

the inner

rvhecl stu[r

axle

is

at 55"

to

thc

bcrrlrs

tirao

of

tb.e car.

15.

(a)

An

automobilc

cnginc

devclops

30

krv

at

1500.r.p.m

and

its

bottom

gear

,

n

.

ratio

is 3,06.

It

a

propeller

shaft

pf

40

mnr.outside

dianrctcr

is

to be

uscd,

.

deLermine

thc

inside diameter

of

mild

B-tecl

tube

to

be

uscd,

assurning

n

safe

shear strcss

of

55

x

1C3

l


11/14

Reg.

No.:

J

8053

B.E./B.Tech.

DEGREE

DGMINATION,

I\,IAY/JUNE

2009.

Sixth

Semestr

Automobile

Engineering

AT

1351

-

AUTOMOTTTru

CIIASSIS

DESIGN

r

(Regulation 2004)

Time

:

Three

hours

Maximum

:

100

marks

Answer

ALL

questions.

PARTA-(10 xZ=2}marks)

1.

why

is

a clutch

needed

in

an

automotive

transmission

system?

2.

What

are

overrruuring

clutehes?

List out

the

variouscesistances

that

a

vehicle

in

motion

has

to encounter

and

briefly

explain

them

Why

is

geometric

progression

preferred

in

gear

ratios?

Give the reason

for

the wide

use

of channel

section

with its web

in

vertical

orientation,

for

the

side members

of

eornrnercial

vehicles.

Why

are

ghackles

used

along with

leaf

springs?

What

are

the

different

sections

used

in

a rigid

type

front

a:rle

of

a

commercial

vehicle.

Justi$

the

usage

of

these

sections.

Iflat

is

meant

by steering

etror cunre?

What is its

use

in

the

design

of

steering

linkagee?

Why

is

hollow

shaft

uaed as

propeller

ahafts?

/

Hon,

are the various

reaction. forrces

and

torques

takeu care in

a Hotch

kise

drive?

3.

4.

5.

6.

7.

8.

9.

10.


12/14

PARTB-(5x16=80marks)

11.

(a)

Calculate

the inner radius

and outer

radius

of

the friction

lining

of a

single

plate

two

sided

dry

B?e

clutch

and

the axial

spring

thrust

exerted

by

the

cluteh

springs

to keep

it

engaged

from the

following

data

:

Maximum

torque transmitted

=

13.56

Nm

Co-bfficient

offrictionsurface

=

0.8

Ma:cimum

axial

pressure

=

8.2g

x10a

Pa

External

radius

of

friction

surface

=

L.25 times

internal

radius.

L2.

(a)

Or

A

cone

clutch

with

cone

angle 20"

is

to

transmit

?.80

kw at

7b0

rpm.

The

normal

intensity

of

pressure

between

the

contact faces

is

not

to

exceied 11.8 x10a

N/m2.

The co-efficient

of

frietion

is

0.2.

If

the

face

width

is

U5 of

the mean

diameter

find out

the main

dimensions

of the clutch

and

the

axial force

required

while

running.

The

co-efficient

of

rolling

resistance

for

a

truck

weighing

OZ2gB.b N

is

0.018

and the

co-efficient

of air resistanee

is

0.02?6

in

the formula

R= kW

x

IG

A\P Neutons

where

A is

the

projected

frontal area in m2

and

V the

speed

in

km/hr,

and Y

is

the

weight

of

the

vehicle. The

transmission

efficiency

in

top

gear

of

6:2:1

is

90vo and

that in

the

second

gear

of

15:1

is 80Vo.T\e

projected

frontal

area of

the

truck is b.b?4 m2. If

the truck

has a

maximum

speed

of 88

km/hr

in top

ga,

calculate :

(i)

The

engine

brake

power

requires.

(ii)

The

engine

speed

if the driving

wheels

got

an

effective diameter

of

0.8125

m.

(iii)

The

maximr:m

grade

the truck

can

negotiate

at the above engine

speed in

second

gear.

Or

(b)

Determine

the

gear

ratios

for

a

four

speed.

gear

box for a vehicle of

weight

13341.6

Newtons

powered

by

an engine

giving

20.6

kW at 1800

rpm.

The

vehicle

has

a projected

frontal

area

of

2.23m2

and has an

effective wheel

disrneter

0.71m.

the

maximum

gradient

that the

vehicle can negotiate is

1 in

4. The

tractive

effort

may

be

taken

as 50

Newtons

per

224A Newton

weight

of

the

vehicle.

The

wind

resistance

is

given

by 0.036?9

A\P,

where

A

is

the

projected

frontal

area

in m2

and

%

the vehicle

speed

in ka/hr.

Assume

a transmission

efficiency

of 0.75 and at

top

gear

the

vehicle is

expected to

climb a

gradient

of

1

in 40.

(b)

\r

.:

1

t-.

2

J

8068


13/14

13.

(a)

A

vehicle

having

an

overall

length

of

360

cm

is having

a wheel

base

of

180

cm

and

the

overhang

at

front and

""*

are equar.

The following

is the

loading

pattern

of

the

side

member

of the frame.

(i)

A2lA kgf

aeting

at

4b

cm

in

front

of

front

axle.

(ii)

A

180

kgf

acting

at 45

cm

behind

the

front

ude.

(iii)

A

180

kgf

acting at

45 cm

in front

of

rear

a:rle.

(iv)

67.5

kgf

acting

at

45 cm

behind

the

rear

a:de.

(v)

A uniformly

distributed

load

of

1.?5

kgflcm

run

over

the

entire

length

of

the

frame.

14'

(a)

Aggrrrning

a dynamic

stress

equal

to

twice

the

static

stress

and

the

allowable

bending

stress is

O00kgflcm2.

Find

out

the

rnaximum

bending

moment

and

section

modulus

for

the

channel

section.

Or

A

semi

elliptic

leaf

spring

of a vehicle

has

its leaves

?Emm

wide

and

10mm

thick

and

its effective

length

is

g00mm.If

the

stress is

not

to

exceed

220725

k

Pa when

the

spring

is

loaded

to

4g0b

N, find

out the

number

of leaves

required

and

the

deflection

under

this

condition.

If

the

spring

is

just

flat

uhder

the

load

what

is

its initial

radius

of

curvature.

TakeE=196.2x106kPa.

T'he

load

distribution

between the

front

and the

rear a:


14/14

1\J

\1.

v.

1*,-l

\/

g'

}\

\,

.{

i

7

(b)

sketeh

a

seni'Iloating

t5rpe

rear axle

coastrrrction

and name

its

co_mponents.

Further

uJ

o"f

tu"

loads

and

stres";;thg

";

th;."-ty;

of

axleg.

Design

a

fult

lloating

rear

axle

from

the

foilowing

data :

Ivlaoirnrrrn

engine

torque

=196

N-m

Gear

ratios

=

4:1,

2.6:1,1.4:1

&

L:l

.:

the

diameter

of

the

ulun

"fo".ic

to

be founj

out.

4

J

8068

at 2352 chassis components design university qp

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