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

    1/14

    .

    ,','-'

    ll'Il"rD.Tech'

    I)BCIRttli

    IIX./LMII\lATlO.htr.

    N0vtilv{iiIilli.ri.)i:liti.ti,iitiiii

    3(}1-}"r.

    Sixlli

    Serncstcr.

    Au

    tor:robile

    Engin+ering

    ,.T

    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;

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    lli,:

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    ffi

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    i

    sl.

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    iilrr

    grrrrce,

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    r-r:.+

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    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

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

    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

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

    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.

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

    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

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

    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:

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

    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