You are required' to:~1-1Findthe- power that could be transmitted safely by the gear unitjL_j~.m~erWear Resistance ~onditions, as well as the V-belt drive. .~I 2 ! Estimate the actual workmg stresses on the gears and thus select ii I suitable materials for them. jL~JFi~.~the reactions at bearings A and B . _L~l_pr~sent a Free Hand Sketch for the gear unit at least two views. 1

j11.~

IJI

Pulley diarneter= 500 mmBelt size: 17x11'Number of belts= 6Servicetactor= 1.25

I,Ij

lI

V-belt: _

.. . IModified form tactor ' - 0.54 -l3/ZJ I, . -Number of teeth 24 108 ...... ....

.t Module, mm .. - 3 3 3 3Normal module, mm - 3- 3' 2.75 2.75Ratio.of.dynamic load/static load

--i ··3.1 ··3-..1- . 1.8 ._-_.. __ 1.R . .

Ratio of limiting load for wear/dynamic toad - 1'.3 1.3 .. 1..05 .1.05 .I

(_Vel_ocltyfactor I 0.48 I 0.48 I 0.71P.71i Service factor r 2 I 2 : ? . 2 .

rr-:·~~u.::.:e:;;..:.:._;:.~:...:::~rt":':':"'::~O~S~~f~f:~~~t-~~:-~'-.:.:.M~:..:...=-p~a~~:~~~ -+I 1~1....:.4_~I_·1':":"1q-~~-:~-+-I-~'~1

t.- Parameter First stage .Second stag_e..

h---·-- ------- Pinion .Gear Pinion I~Gear~-.---.--"I- 83 80I Tooth width, mm . - 32 30 .1-;--.-----.-- --

Gear Unit:

The sketch shows the outlines of a Concentric Double Stage Speed Reducer.which is directly coupled to an electric motor. The first stage is a straight spurgear and the second is helical gears. A V-belt pulley is attached to the outputshaft and rotates at 100 rpm. The electric motor speed is 2250 rpm.The unit is designed under the following conditions:

Machine Construction andDesign of Machine. Equipment

---

Time: 3 Hours1St Semester, 2004.2005

AIN SHAMS UNIVERSITY'FACUL TY OF ENGINEERING

DESIGN& PRODUCTIONENGINEERINGDEPARTMENTThird YearMechanical, Power Section

...

b 5 6 8 10 13 17 20 22 25 32 40 I SOh " 4 5 6 8 II 12.5 14 16 20 25 132.)

dOl ,22 32 45 63 90 125 180 212 250 355 500 17~~

Minimum Pulley diametcr (dill),mm:

o '9==180 ±2a= 1800 ± 2 sin" [D-d i 2C]'

• V-Belts Design Equations:

cmax: Permissible (maximum)<?rror,-l~lmr,

Module Commercial Accurate PrecisionUp to 4.5 50· 25 12

6 60 30 . is7 .. 70 .. 35 17

- 8 80 40 2012 100 50 1--. 25 __-'- I

._.-~25 120 60 30 ,.

• 1\ = PI tan a. sec r• P, = PI tan r

(,2'P _ P \Kd b cos y +P,1 cos Yd - t + 0 15 ~

1+-·-'-·Kd b cos2Y+PtV .

C : Probable error [um]

• Pen:: den. ky. b . m• pw = k., . kn • b . Dp / cos' Y r

(-.

• npf"........ation ..~~~~_- (\ 1 1 ~ I rl rr. • 'I'r ~~ -~"' •• ,. u....,.. ~...v •....,•. - V.11 C I tIl Cp T 11CgJ

• Speed factor = 2 u / [1 + u]• Esl:: (21 xl04 MPa) ECl=: (12 xl04 MPa)• Pen= 1.2 Pd

• Gears Design Equations:

"• PI ::;,(Jb . b .m , K

Useful Data

, ."'. Machine Design-January-2005- Third YenrMechanical, Power Section/Page: 2~.--"'-.+'

Material O'~ O'y

Cl0 420 250CI5 500 300GG 18 180 ---GG22 220GG26 260- I~---GG30' 300GGG40 400 250GTW40 400 220GTW 35 - '350 200

GS 38 380 - 180GS45· 450 220

- GS 52 520 250GS60 600 36015Cr 3 600 40016MnCr5 '800 60018CrNi8 11200 800

Material 0'. O'y

C22 550 300C35 - 600 370C4Y -660 !'4-00-C60 750 49J)'·SI.34· - 340 190S(37 370 200SI42 420 220SI 50 500 250SI60 600 ·300St70 700 340

30 Mn 5- 600 : 55037 Mn Si-5 900 800 -

42 Cr Mo 4 980 '-76036 Cr Ni Mo 4 ·1000 900

- 34 Cr-Ni Mo 6 1100 -90030.Cr Ni Mo.8 1250 1050

Strength of somematerials .(Ultimate and YIeld Stress, MPa)

:~Machine Design-January-Hltls- Third Year Mechanical, Power Section [Page: 3/4/'

Transmitted Power Qer Beltl IKw]

~ 5 6 8 10 1"3 17 20 22 25 32 40 502 0.018 0.037 0.074 0.140 0.272 0515 0.736 0.810 1.104 1.766 2.723 4,4164 0.035 " t'\ .... i1 (\ 111.1\ 0.277. 0.545 0.957 1.3'98 1.693 2.208 3,459 5.446 8.832L'.v,-, v.........

6 0.050 0.110 0.206 0,405 0.810 1.398 2.061 2.502 3.238 5.152 8.096 I" '}'\".-8 0.063 0.140 0.265 0.530 1.030 1.840 2.723 3.238 4.195 6.771 10.30 1G.93

~ 0.074 0.162 0.316 .0.640 1.251 2.282 3.312 3.901 5.078 8.170 12.51 20.6112 0.081 0.184 0.353 0.736 1.472 2.650 3.827 4.490 5.8.88 9.421 14.72 23.5514 0.081 0.191 0.383 0.810 1.619 2.944 4.269 5.152 6.624 10.60 16.19 26.5016 0.081 0.199 0.412 0.883 1.766 3.165 4.637 5.520 7.213 11.56 17.66 28.70

~

0.074 0.191 00412 0.883 1.914 3.386 4.931 5.888 7.654 12.22 19.14 30.910.059 0.177 0.397 0.957 1.987 3.533 5.078 6.035 7.875 12.59 19.87 31.650.037 0.155 0.361 0.883 1.987 3.533 5.152 6.109 8.022 12.73 19.87 32.38

0.110 0.309 0.810 1.914 3,459 5.005 6.035 7.581 12.51 19.14 32.3826 . 0.059 0.221 0.736" 1.840 3.312_ 4.784 5.741 1,434 11.85 18,40 30.18

( 28 - - 0.132 0.66 1.693 3.01~ 4.4JG 5.226 6.845 10.89 i6:93 27.23

130 .- - 1.472 3.650 3.754 4.563 .5.888 9.568 14.72 23.55' i- - - -

...._ .._ ..._-----,..

-A B~- ~,;~- ;?;?7

_J~~. 2a

ElevationSide View

- ·f

Bearing A

Straight GearHelical Gear

v: belts

Machine Design-January-2005- Third Year Mechanical, Power Section {Page: 414J

<l » 7..y..3~OXIOO -~.'27 1'Y\ls6'0 000 -

KN~wI?J -:= I·0 '5

P.1 (ft = ,·8

oJ

-== 23.55'2·753·

.-Ic,.s

\)== I\. 1:.12 )(2.'250 =- 8.~T Mis·be:> 0.00

?J ::: '3. "80 b \< N

_~_-P'~ 'ft ~ 1.228 KN

\< e ~ ::: 2)14·5 = {.63~" J+u S.~

(;( /Irs! Sk'le:or -

Pw: kpw. k". b ..df

-iil. sf~ge

ell z: "3 ~ 2. "" = 72 VnW\

d1. = '"3 x \04 == "324. """'"sf f!.(!d '('~C'o = 4.S -:Gnt" ~·$t~r.le C '"32t. + '12 s: {'1 '8 ""WI

2-

2'ld sfo..qe

d3+ J" = -:Y16 dlt :::5 d.s

,'. ~ d3 ::: 33 b

Id3~ 66 ~~J ld.= -:no~~2:3 ::: 2'2.. Z~ = I/O

sfeed ra-Cd == 5

--~ l~f'l:::587 Mfa I~~:4~o Mf~ I

.. 6b = 115. b Hfa3

-0.7.1 )( 0·4342 »; \·2-

\ .Z F - 1-/Q_ =: I I.2 .g

~-~ "'1

kyJ:: 0.52.

.. Fa( 2 rul Sf/).3 e. ~.

~Z\Fr.>::: . 2. '2. -::: 28. S 5i CO~., ~

---900 L6UF~410 ~f;]- . --- -~..

:: 410 ~ ~.';I\~ ~)E)~~ ~_3-3.3 -MP~1,.

It -== ~_!_!_I n~ = 6b.8.1(1

c : S'Pr '=L 1~7 HPa.

,.For til sfa.~ :v

kJf"" 0.s4_

k'j9 :: 0.5/2

z:0.62.S x.4 x (;/.2."5

0.....:::I 0.625._____., froM bll\e :"kz - Soo- ff~

ks:: 1·25

,...,/s:: 2.6[

--2 222.65 + i( 2.09_ ®

- ~

~ :: 360

i t@@tl F., _ r'"10 2 _.~:- .,. . \...:, .• 2. - f" -'._

_ _- ~ -

_!1:= 360. l-

r--- =___.,

-2... -~2.3:;'3 -t 584·

t1. == 2625 " b:== '8662 <5 ~-i. ""fro

- 262.5 N

1"20 ......

IS:60 M _

~ ~.r~1-:= ft \Q.f1'r5-:::60"2.'2. - "Th.n 23.ss

!~ICf

.. 6'0'" )

-= 602,'2. -\0.1'\ 2.0 S.ec. 2~ .s s

=:eo2."lN

Yower'ir

10·4\·121

~('l. -::: . ft "\"0.(\0( Se<a

= 1;41 N

Ft = 122.8 NI

fr ::: \ '2.28' t~f"I2.0\