Ain Sbams UniversityFaculty of EngineeringDesign & Prod. Ene. De

Third Year Mechanical powd23 - June -2002

Time allowed:3 hours

-Students may assume any missing dataconstructional drawings shourd be fu[y cinacnsioncd withTrachining symb_orq and crasses of fits crearrylndicated.

A speed Reduction unit which_feeds a packaging conveying system in afr:!,y, is designed so as to allow for the foliowin!:l-The speed reducer is.to be coupled to an electrii motor rotating at 1500 rpm.2-The speed of the packaging conveying belt is 0.1 m/s.

The Speed Reduction Unit consists of two gear reductions (a Worm Driveand a Straight lpul Gear Drive) in addition ti a third reduction in the form ofV-BeltDrive.Thesketchsho*sihelayoutorttrisunit'

You are asked to:' Find the Maximr* Hor..power that could be transmitted by the speed

Reducer unit, allowing foi no overroad conditions

o Present a Frec Hand sketch .for the speed Reducer unit addin* ,n.necessary suitable Rolling Bearing.

t In your calculations consider the followig:Worm Gear Drivg.

Modr-rlc, rnnr t4l5702s020.05406010

3550

Preasure an11le. degWorm pitch ditrmeter, mrnWorm lei:gth, mnrWorm starlsCoefficient of friction betweenNumber of gear teeth

Allowable ture rise for the uint, Co

Effective gear tooth width, mm .

Gear rim material phBr, All. Bend. Shess, kg/mm2Worm matrial NiSt, All. Bend. Stress, kg/mm2 ....

113

23-June-20t

2- Straisht $pur Gear Drive:. Consider Static Stength Conditions OnlyModule, mm .

Numbehof teethIrlumber of teethPinion diameter,

for pinionfor gear

Tooth width, mmPressure angle, a.g. . . .. .... ..........Pinion material C45, Ultimate stress, kg/mmz

Qear material St 70 , Uttimate stress, kglmm2

rnm

3

46184

t3850209070

3- V- Belt Drive;

Belt size I qoxzsNumber of belts .. .... . . I ZSmaller pulley diamet€r, mm 300

Some useful data.

Pr :Ob*b*m-K K=KrrKy/K,

dified form factor

o q=tan1"/tan(I+p)t 632 ( 1- n ) HP = 330. A.4t

o For V-belts sfzc 40x25

tanp=p/coso(A.. in m2)

0 = 180- 2 sin-' (lt - d) I 2 cN=HP/(HP/b).1(r1

Velocify factor for gear - 3 / (3+v)

o:zTu: cfactor 0.4610.47

V, m/s I 2 3 4 6 8 l0 l2HPib 4 4.5 6 .7,5 1l t4 l7 20

ontact angle lactor'

0 r80 170 i60 r50 140 130 120 u0rq i.l 1.07 1.03 1.00 0.94 0.88 0.8 0.74

213

- Machine Construction el _ 3 - June -2002

Worm-wheel

Spur Gear D.rive

0 300

3/3

Spur Gear Drive

.ConveyorConveyor

tIIIIII

Examiner : Asso. Proft Hesham Aly Se.nbet

. ", /:""

V{or,n Drive

d,r=lo *...o16=-Er'1:-l<1114-44*;.

L* = zso -*DU = ro^rZ = tlq x tao = 56o

",,.

) = toi' zx 44 = zt.i = 6''_x xJ o ..-:

rL= ,f"1 2 S=hi'/_/-"n zt.8

= 6.86fan(zt.B+ z.q6)

tlf = 33o. 7-2. 6f' 6s2 (t_ a)

2ooZ

de

Hr =,I

l,Grn €eirVod - -?(bN

J _ -._=-___--:_ llt x-55o X-ISda orc

l, 1

tstvKy = o,39

6o 6oo

mn= /4 Cos ?1.8 = 13 m"n

= 2.7 r,'ls

?t : 1'2 xz = 7.8so,s1

Hf=4 = uL#L =Vq Hpl

= 7o - z.zxl\ = 3?.2------:3

T1 31.2 xo.6 x 35 = 248 b,*

-xr- Fi,,Z5o

= toi' oos = z.q6

Qrs lS

6J2(l_o.86)

y/r, ^ shoftJ.' = 70 - 2.2 vn

174| - :lsd L. ___72_

l1P = a.-Y;- =7s

/6

Op= 3*\6 ='l3g rn$^

TS = 5S2. 'nyn

Vp = :t xr.r8 xi5 = o.s4 *,lsI 6o ooo

v3B1 o .S4

ky = o.ls kv =o.lgJP- t?

o .8 ltT xo..A5-- t. 2s

i's tz x o.54

Pr 9o''r= €HP=

Pto = f "r3

HP =

Betf D rive

75

o.8 ttl t, o .48

x Sox 3 = l37Z k1

x 5o2<3 = llla kg

b- tg HP

xI '2s

tt 38 a a .5 47s

15T = t6:75 rf*

,tIJ

t'be(t =

-x*Voox 18.75 = o.Z?4 _lS€o ooo

NGnv.= n"==t : 5oooo xo.lfD T :( Boo

speel r.^t.o = tA.]?- = 2.q4€.2 6

T= 3oox z.qli = fla=.G m'

e= l8o-Zsii' 883'6-:oo = 15l"z 1 \2ooke = I

HblA = 3.7s

l7P= Zx 3.75xI =

6.ze e r.D.ur\

eoO

-fr" *^A, Po a er =