You are required' to: ~1-1Findthe- power that could be transmitted safely by the gear unitj L_j~.m~er Wear Resistance ~onditions, as well as the V-belt drive. .~ I2 ! Estimate the actual workmg stresses on the gears and thus select i i I suitable materials for them. j L~J Fi~.~the reactions at bearings A and B . _ L~l_pr~sent a Free Hand Sketch for the gear unit at least two views. 1 j 1 1 .~ I J I Pulley diarneter= 500 mm Belt size: 17x11 'Number of belts= 6 Servicetactor= 1.25 I , I j l I V-belt: _ .. . I Modified form tactor ' - 0.54 -l3/ZJ I , . - Number of teeth 24 108 ...... . ... .t Module, mm .. - 3 3 3 3 Normal module, mm - 3- 3' 2.75 2.75 Ratio.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.71 i 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 80 I 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 spur gear and the second is helical gears. A V-belt pulley is attached to the output shaft and rotates at 100 rpm. The electric motor speed is 2250 rpm. The unit is designed under the following conditions: Machine Construction and Design of Machine. Equipment --- Time: 3 Hours 1St Semester, 2004.2005 AIN SHAMS UNIVERSITY 'FACUL TY OF ENGINEERING DESIGN & PRODUCTIONENGINEERINGDEPARTMENT Third YearMechanical, PowerSection
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
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 .
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