fe_01m_s - ME 466 - Machine Design fl SOLUTION z/ 1S:ummer...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ME 466 - Machine Design fl SOLUTION z/ 1S:ummer Term, 2001. . $72,“ inal Exam, 200 Pomts, Open Book D; p 7 It; 1. (20 Points) The pinion in a gear set is a spur gear with 20° full depth teeth and a diametral pitch of 14. It has 28 teeth and rotates at a speed of 8,000 rpm. The mating gear has 42 teeth. They both have a face width of 1.00 inch and are made of alloy steel with a core hardness of 340 Bhn. The tooth profiles are done with a precision that justifies the use of curve C of Fig 15.24 and the assumption that the teeth share the load. The loading involves mild shock, justifying the use of Ko = 1.25. Estimate the horsepower that can be transmitted with 99% reliability, based on tooth bending fatigue and a fac ; a . i of 1.80. HP. W 577* E 57501;)”; ’ Q2 1 f P“ 5“: WMfWGf/fl/f/M/m KV— , 0mg 5 I: ,6‘24 :; [(03 [elf/(«I14 ” mo ‘ ' P I " fl kV k0 kl» 53175, (665%. ILT’thf 0’. J, :WWX'ngg’V/WW : 5% guaomuflé/ I55 g . r : ‘7'“5/ (r: 307Fr 7; ’ “)8 M Mai} 77 _ ) Pay/p5" :9 “WNW/F7, Tfrrg'Q/M/j :W’é’ficg QfMU: f H , r- l/ ' /-L "fiJ—f 905/?“- Hflj 7/1 7 .1359ng m; W - A 7 5/3 2. (10 Points) The gears in the previous problem have been case hardened to 500 Bhn giving a high surface hardness. Estimate the horse power that can be transmitted for 2000 hours with 99% reliability and a 1.8 factor of safety, based on surface strength. HP: /3 A . . , , Al: gym/y 4% Wm : zéyf Mi~ W A" /I/ /y 9’ c é : ,Q/fi/yflj "/fl I z: 7f 5;, : 54, q], CR : Mm; (gem): on As; 9})”; : 60542” 7/57, : 859:???” : ,0747 AGE/362; :[f :c ,t : W :/M;),/‘F 0/; I’ 640; tug m [(QMWZW/ I j 7' W5" Pa/ @359 :; /5’flf§/E :lgogow TPJEP/fl/ 3&7/“2/7/ fire: /{/UJ/ :/fl&m// .~ Zia. -; Mum?) - W 690.2? mm; ' A)?!” p Summer Term, 2001 MAE 466 - Mac ' _ esign J L / G 2 3. (25 Points) A full journal bearing has a diameter of 0 , ian, and ports a load @\ n 7 W . . . . - . . a; newtons at an operating speed of 800 rpm. The bearing radial clearance 15 @md the desne minimum v ‘ film thickness should be twice that given by the Trumpler criterion. The average operating temperature of the ‘ / )2”? oil is to be 75°C. Determine the oil grade required, the power loss, the flow side loss, and the oil temperature a rise. Oil Grade Required: W35 1’ Side Flow Loss: ION” em? Tn”, VCflfpfl’; I ‘ .. fl: /¢ 7mg; Add: ,W5+10WD:IW57«W04’[}£/ 14W 5/ ,3'5@ 3% use fflg’ya 1040",,” 1:96am) = , 47/7»... Egg/e fi ; $29 figégj: ,Mfy Fl If]; W17“ %"/ lig’¢ '-%Z:.967 1—4 +, - ' ' 7W reevwfflmflf“ e ., 5“ ./7rel/ Pyr: “27/4/34 23': 3 v F .__ .. F“ 272752;?» ' 5m; 1323/1 eke.) ema=(¢,2,DZ/¥/B}W *3/14?” - 6/), /7 47:,55/Q :: /&40M«}/S - : fl 1 ,, fl ‘1’, S p 5 9" ,9) yer/m 473%.: 42:)th 3 )2 /3,70( 4. (25 Points) A shown shaft transmits 50 horsepower ata C? >7 lug—76¢ (lawn/"4 Fe :991/ speed of 2500 rpm. The bearing at B is designed to take all 517 of the axial load. Determine the following: Maximum Shear Force Maximum Bearing Radial Load Maximum Bearing Thrust Load ., 12L I 9‘” ' W - 54 a 5/73 IM/[Jj—UJJ 4W ,1 a g 4 ,9) ‘7 w J J ‘ 0 97’“ D = 3/“ JV” LL 92-1%(1’0) ’ y 6 Va 92; : 37g 5*} =0 = wwsy “5"” "5 Wm ‘ 52,1595» 8),: 4 __. icy/4 Hmmf M} M8 7 final/0i :Qfdol KM“, ig/Ol "/5 I40: /57.1+;o“7“:/fl4' . ‘WMH Summer Term, 2001 MAE 466 - Machine Design 3 5. (20 Points) An ordinary deep groove ball bearing is to be used on a shaft at a location where the radial load is 600 pounds and the thrust loading is 450 pounds. The shaft (machined from 1020 steel) runs at 1000 rpm and can be considered to operate with light to moderate impact. It is to operate 8 hours a day, 300 days per year for 4 years with no more than a 5% bearirgfailure rate. Select a radial ball bearing to use in this a lication. < ‘ V, 75 ./ "MA/J47 Bearing: L/f. al/J_))flg fag/«1W ,r .3 5.6611. 7; ’F=F(/+///f/ft—?57 L /' -’ ’1 'l C V I F“ I » y F (—1 I? M” : féf/é (iffé Lfl) Chi, flip/:4 SEX/9‘ M} — .53 x91)” 5) L = /(Wre// 94/ {024% {7/ M”! ’I/ W X’- I 57; X/fl‘ret/ ' #r $2,544!ng /< =43 7';sz Hi 0/1”?” firm are an 67/4/16” bfé/HIW/M/b k». v/f 4mm 4,” m? owl/0 : Mow; : Mékl/ 6. (25 Points) Thtate of stress at a critical point on the surface of a machine member is determined from strain gage analysis to be: O'x = 20 kpsi (tension), 0y = 10 kpsi (compression), and 15x), = 25 kpsi (clockwise). The geometric stress concentrations at this location are known to be ’50 for the normal stresses and 1.20 for the shear stress. Determine the factor of safety of this part if the material is: (a) 6061-T6 aluminum (Appendix c-10) _ FS = /. 67' (b) A390-T6 permanent mold cast aluminum (Appendix C-II) F S = /I (a) Q06/ 76 244mm», VZfi/dryl/M ~’ AWL/J ‘ /Q0,X} )5 . { uje narumz/ fi/egflf’l ? Q 333 5y 3 If \‘ /p$74 Sf/erfe/lm’f ’91? ‘ ,6 gm (as)iggwf-pwaéwfiow) = 4M ’ -5-(/00W up- 7’, w 57:, “WW/Jo 0} Magic 5434/ 97/2)”; C: BI} 1445)) R 7 my :23 vi a? (/0 J. F 7 Ana» :9 B:/ V : ii? {& 5 5y (“A/AM e12 ewe. .: W, 5L:4f/<n' ’ '57 R5 Q?!” 15/ f. 0; :Cf/l : / LLa .20 - ago/g : 19/)” .1; [r . . , 6: (HM k I _ 5“ __ g (ff, r - WIMP/49 4" —-§' “> 6' am— W 62) W- assum/ry file 75;] 45F'W’-—I/’.'// ‘57 39%-?)f ,6 PM ,2 Summer Term, 2001 MAE 466 - Machine Design 7. (25 Points) The force, F(t), varies from a low of 300 pounds to a high of 600 pounds. The stub shaft is made from 4140 steel, machined to shape and then heat treated by quenching and tempering at 900°F. Determine the factor 0 .: v u .- r bracket's stub shaft in this ap lication based on a life of 10 million cycle my 5 map/c (7’6 fan; F PhD—’g/J (I) 21/ V7!" / .. . ‘ All parts are machined n = A F 1/32" fillet radius F , 332.721”: 95—0 ‘2) 4; : w, m; 7; : arm m v ' Fa ‘ 6w : /r0 :5" y; : Mme; m = 4458/ V A A , - 4),): .133? _ I W - r = 1 if ,/ — ,5 @ 6 V/Vll/fé/aft’l?v It / fléyI§¢/,174/ _ aél (I a,” J I W l9] 44,7 ' . , > A & ‘ ;_ MW?” . agawfir‘a/M’ 0&4 7 /6fl’ y- ’3 a D f M s- f L9 57477 a” éaw/wwv 56—114, 0%: -l/ ? %4%7F5 F (iv?) Wf+/5,X I; S“ s” F; éMf'flEA/ Ff 9. (10 Points) Specify the proper tightening torque (in foot pounds) for a 3/8-24 SAE grade 8 bolt. Tightening Torque = 9 5’? E lb 724/, /y,/ Ar : ,0976/4“ Val/5&9 s,, = NO kn $1,475“ Ming/z. 2;; 7,95: 79!?2/5 7/; Gui/,5 1; pp?!) 7643,) = 7///n/; = f7fi/j Summer Term, 2001 MAE 466 - Machine Design 5 8. (25 Points) A helical compression spring is to be made from oil tempered wire (ASTM A229). The spring force will vary from a minimum of 20 pounds to a maximum of 40 pounds when it is compressed an additional V2 inch. It is to use a wire diameter of 0.10 inch and should just reach yield if compressed solid with a force 10% higher than the maximum force (i.e., 44 pounds). Complete the table on the right for the required . spring. [NOTE.' The number of load applications is sufiiciently small to justify the assumption of static loading. ] \\ Outside Diameter Inside Diameter Wire Diameter 0.100 in Spring Index \ m ya 32% \ Spring Rate Free Length Solid Height Total Number of Coils § \\ i? \l N . \1 § I ’e‘f‘rc 49— .20 I Will the spring buckle when fully ‘ f f K J 31%;: ’/ ’ yflj/j, compressed? YE N .L (J usti ; our answer!) circle one M ,/0 : 3'59"”! 1 ~ ' / E//l.7’?5uz‘l°)fkfl W x. 7; = ,4 éar): Mm L5 s/l/re/ : ’77 I: W eFD ’1": lg #7 dffuwc 4&M F,” L” i; 7%!" k5: /+"l-;:: [if I m/jj I F/‘MV XD: f6” 7> =€§§§$4 6/” Le= 15"“; [gr/’0‘ : (77;..4-4‘73” I t I, r/ é a 6”” 00:D+/( =,/flf,fé'-’,% M l 7 10:1»! : ,%~,Me .75 %‘ r fig; 5 M .. p C: 7’64 ' F u M 7 - 4 701/6 , . re _, [IN/wee W k7???” ’9 IV” ggféfqfl [/07 Wag/{e fl: 57/7 fl/rr/l/f’l 10 (5 Points) Specify the dimensions of a square key to be used with a 3/4 inch diameter shaft. / 47,6 x 3% >< /,5” I [Keys are, /9 07z Mame/ex ‘5: fa olfl 75mg; f4€é//4k{yf(é/ Cm/q/ég 7 / . /- 4 $9): L / Are/9): Mr” ‘7 (1,0679): /,5"’ ...
View Full Document

This note was uploaded on 07/19/2011 for the course MAE 466 taught by Professor Wallace during the Fall '09 term at University of Alabama - Huntsville.

Page1 / 5

fe_01m_s - ME 466 - Machine Design fl SOLUTION z/ 1S:ummer...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online