Mechanical Engineering Design: Comparing Belt and Chain Drives, Designing Hybrid System, Exams of Computer Aided Design (CAD)

Download Mechanical Engineering Design: Comparing Belt and Chain Drives, Designing Hybrid System and more Exams Computer Aided Design (CAD) in PDF only on Docsity! CORK INSTITUTE OF TECHNOLOGY Higher Certificate in Engineering in Mechanical Engineering – Award (NFQ Level 6) Summer 2007 CAD & DESIGN (Paper 2 – Design Written) Time: 2 Hours Answer Question 1 (40 marks) and two other questions (30 marks each) Examiners: Dr. R.K. McMullan Mr. J. Connolly Dr. P. Delassus (1) Compare and contrast belt and chain drives under the following topics: • complexity • ease of installation • life • lubrication • mode of failure • maintenance (6 marks) Give an example of a machine drive system that might use both belt and chain drives. Explain clearly why a designer would choose such a hybrid drive. (6 marks) It is necessary to transmit 27HP from a steam-engine turning at 1000rpm to a large circular saw-blade that cuts wood; the blade must turn at 394rpm to run at its optimum speed. The output-shaft of the steam-engine is spaced 142.2cm from that of the blade. The saw could be in operation for up to six hours per day. Design a belt-drive AND chain-drive to fulfill the above requirements, within the following constraints: • The overall dimension must be less than 2m • No drive should use more than three strands • For the chain-drive, only chain with ¾” pitch is available For the belt-drive specify: • Belt section • Sheave sizes • Belt length and number • Number of belts For the chain-drive specify: • Simplex/Duplex/Triplex • Sprockets • Number of links (28 marks) (2) Regarding the design process: • State the reasons for adopting a prescriptive approach • With the aid of a flow-chart describe the main phases of this approach, and the activities that occur within each phase • Explain the importance of making a correct Functional Analysis of a product to be designed (12 marks) Make a Functional Analysis of a Climate-Control for an executive vehicle. Note: • a Climate Control maintains a user-selectable preset temperature in the cabin of the vehicle, regardless of the external temperature. • when cooled humid air produces condensation (8 marks) Make a full Black-Box analysis of the machine. Sketch its proposed functional flowchart. (10 marks) (3) Discuss the use of Setscrews as a means of attaching a hub to a shaft under the following headings: • complexity • point configuration • load capacity • typical applications (8 marks) When more than one setscrew is required, sketch possible configurations and placement of the second setscrew to improve the load-carrying capacity. Give any rules of thumb that are relevant. (6 marks) An engine turning at 4200rpm and producing 5.5kW at its φ15mm output-shaft is coupled to a generator via a hub that is secured with setscrews. Assuming a safety-factor of 35% is required, design the coupling using data in the table provided. If, instead of setscrews, a transverse pin is chosen as the method of attachment, what pin diameter is required if the same safety- factor is to be used. Note working shear- stress for pin material τ = 100MN/m2. (16 marks) (4) Give the definition of a Threaded Fastener. Explain how it can be manufactured. Make an annotated sketch of a standard ISO metric thread. (5 marks) Discuss the importance of selecting the correct fastener material for any application. (4 marks) Explain the term Property Class as applied to threaded fasteners. Using a property class of 8.8 as an example, clearly explain the meaning of each number. What does the last number tell us about the type of material; use graphs to aid your answer. (6 marks) From the tables provided calculate the maximum external load for an M14×2 10.9 fastener, using a 45% margin of safety. On the supplied nomograph calculate the required assembly torque, if the fastener is lubricated with molybdenum disulphide grease. (15 marks) kKW-RATINGS (PN) CROSS SECTION Cc (2212.5 mm) kW per belt at 180° arc of contact Pitch diam. RPM OF SMALLER SHEAVE of smaller Speed sheave ratio mm 50 100 200-300 400-500 600720 800 $50 1000 1100 1200 1300 1450 1600 1800 2000 036 082 1.05 141 174 202 229 258 975 B04 312 328 342 353 387 376 3.80 375 037 083 1.08 1.45 17 209 237 262 284 214 Ard 399 384 966 330 369 393 388 038 086 1.12 1.50 1.85 216 245 271 294 325 B34 351 366 378 392 402 407 400 039 088 (1.16 1.55 191 224 253 279 30¢ 325 945 362 S77 391 48 416 420 414 040 070 1.19 1.60 1.97 230 261 288 319 346 355 374 490 403 418 498 494 427 100045 («O79 187 188 292 2/6 374 351 386 431 445° 4.71 1.05 046 082 «141 194 241 285 3.26 3.64 299 446 4.60 4.88 199 120 049 0.82 1.46 2.00 250 295 337 376 412 461 4.76 5.04 150 049 0.07 161 208 25€ 305 347 389 425 476 492 5.20 223.00 051 039 155 219 266 344 359 400 499 492 5.08 5.37 516 542 662 577 581 534 5.60 5€1 5.98 601 551 579 601 618 621 570 5.99 620 638 642 587 618 640 6.59 662 1.00 054 0.96 168 233 293 349 4.00 449 493 556 575 610 643 672 799 758 768 773 105 055 099 174 241 303 360 4.14 4.64 512 575 595 632 665 696 734 765 788 795 200 1.200 «057 1.02 180 250 314 372 428 4.80 528 595 615 5854 688 718 7.58 768 8.17 824 150 060 1.05 186 258 324 385 442 4.95 645 614 635 675. 7.10 743 7.80 8.17 846 854 2300 062 1.09 192 265 334 397 456 512 £63 634 655 596 733 765 810 899 868 876 06¢ 116 207 288 364 434 5.00 563 621 7.01 7.26 7.73 817 854 905 942 9.64 Ys2 O67 120 213 299 276 450 518 583 643 7.26 7.51 802 846 883 927 9.64 10.01 1008 069 124 221 3.08 989 464 535 602 665 7.51 7.80 624 868 9.13 964 10.01 10.38 10.45 G71 120 220 310 402 400 553 622 687 773 802 8£4 9.05 942 994 10.38 10.67 1075 G74 192 235 328 414 495 5.71 642 7.09 802 824 8£3 927 972 1030 1067 10.97 11.11 100 0.76 1938 247 347 499 526 698 664 758 854 883 942 994 1038 1089 11.33 11.63 11.63 1.05 0.79142 255 3.88 455 5.45 7.09 780 889 913 9.72 10.30 1075 1133 11.70 1207 1207 260 120 082 «147 264 3.71 4.70 563 7.52 810 919 949 1008 1067 11.11 11.70 1214 1244 1244 150 0.84 «152-272 3.83 485 581 G71 748 839 949 972 10.38 10.97 11.41 1207 12.51 1288 1288 2300 087 157 282 395 5.00 600 693 7.60 861 972 10.08 10.75 11.93 1178 1244 1295 1325 1325 1.00 089 162 293 413 5.25 630 729 8.24 3.13 1630 1067 1126 1192 1236 1295 1340 13.62 1332 105 0.92 1.68 9.04 4.28 5.43 652 758 8.54 942 10.67 1097 11.63 12.22 1281 1340 13.84 14.05 13.84 200 120 «0.93 174 S14 442 562 G74 780 876 972 10.97 1193 12.07 1265 1325 1364 14.28 14.50 14.28 150 0.99 180 925 457 5.09 696 802 9.19 1901 1195 1170 1244 18.17 1369 1428 1472 15.01 1472 S300 102 tes 304 471 S09 718 992 942 10.09 1170 1207 1208 1947 1419 1472 1551-15-46 1816 1.00 1.05 191 347 489 624 751 868 9.72 10.82 12.14 1251 13.91 1450 1509 15.98 15.38 |1465 1.05 1.08 «197 359 5.08 645 7.75 891 1008 11.19 125¢ 1295 14.43 1501 1558 15.90 15.90 |15 16 B15 1.20 1.12 205 3.71 5.25 663 802 927 1045 11.58 1296 1340 14.20 14.94 1546 1612 1641 16.41 11575 _ 180 116 211 383 542 689 824 957 1082 11.92 1340 1384 1465 15.38 1597 1683 17.00 17.00 |1627 300 119 218 396 569 7.12 854 994 11.19 1295 1984 1428 15.16 1590 1656 1715 17.62 17.52 |1671 1901.21 224 408 5.76 7.95 £89 1016 11.41 1265 14.20 1465 1646 16.12 1663 17.08 17.15 | 16.63 1.05 1.08 2.92 422 5.07 7.68 €.13 1052 11.92 1303 1466 16.16 15.07 1663 17.16 1786 17.81] 17.15 365 1.201.980 236 136 6.17 7.88 6.40 1080 12.22 1347 16.16 1568 1666 17.22 1781 1833 18.40| 17.81 150 1.35 247 450 637 810 €72 1126 1266 1301 1868 1619 1708 1781 1833 1884 18.02| 19.08 22300 1.38 255 464 658 3.99 1008 1163 1303 14.43 1619 16.71 1769 1833 1892 1950 1958 | 18.92 ‘area indicates min. recommended pitch diam. Dynamically oalanced sheeves are recommended. LENGTH CORRECTION FACTOR (C2) BELT NO. S168 8 90 105 112 120 198 158 162 180 210 240 270 900 990 960 420 Enomiength 19360 1792 2097 2351 2732 2910 3113 3519 4078 4780 4637 53°90 6161 6923, 7685 8447 9209 10733, Ce 0.80 085 0.89 0.91 0.94 095 0.97 0.99 102 103 1.05 1.08 1.11 1.44 146 149 1.21 1.24 kW-RATINGS (PN) kW per belt at 180° arc of contact CROSS SECTION D (32x19 mm) Fitch diam. of srralier Speed PM OF SMALLER SHEAVE sheave ralio mn sc 100 «150 «200-750 AD 44D BON 50. BO 770 « £00 aD fond 1100 1200 1.00134 «232 317 396 487 534 5.97 656 7.12 7.65 810 861 942 10.08 10.82 1097 11.25 11.33 195 «198 P41 39 4.09 4.84 $52 818 679 798 788 839 891 972 10.38 11.19 7133 11.63 11.71 120 148 249 330 4.24 5.00 $72 899 7.02 7.58 B17 BEB 9.20 10.01 10,75 11.66 11.78 1207 12.14 150 147 257 351 4.07 517 591 860 726 788 846 891 949 10.38 11.41 12.00 1214 1244 12.51 300 153 264 362 451 633 609 581 751 819 868 927 9.72 1075 1141 1296 1251 1288 12.95 100 1.67 2.95 408 5.13 610 699 7.88 876 9.49 10.30 1097 11.63 12.81 13.84 106 1.74 «3.05 422 631 692 7.27 817 905 986 10.87 11.33 1200 13.25 1428 1631 18.82 15.97 1882 16.34 18.63 S15 1200-179 «316 437 549 654 751 846 942 1016 1097 11.70 1244 12869 1479 1612 1834 1693 1715 16C 185 3.25 451 S67 675 7.80 8.76 96¢ 10.52 11.33 1207 12.88 14.13 15.31 1663 16.93 17.44 17.66 22300 1.91 336 466 5£4 696 602 905 99¢ 10.62 1170 1251 1325 1457 1875 17.15 1744 17.93 18.25 400-205-386 5.10 645 773 B91 1008 1119 1214 13.17 1413 105-212 878 528 668 802 9.20 1045 1156 1259 1369 14.57 385 120-749 BAT 54h BIO APA G57 10.82 1200 1308 1413 15.09 150 2.06 4.04 561 7.°3 884 996 11.19 1226 13.47 1457 15.53 300 293 «417 562 7.35 88S 10.16 11.41 1268 13.91 15.01 16.12 16.83 17.96 19.58 *995 20.53 20.90 1745 1862 20.17 2068 21.27 21.64 17.81 1921 2060 21.34 22.01 22.47 18.33 1987 21.64 22.08 2267 23.04 18.92 20.46 22.28 2282 23.40 23.77 IV WU «247 445 624 7.95 949 10.97 12.51 1384 15.16 16.34 17.99 18€9 2068 2237 24.29 2472 26.47 25.69 105-285-459 6.43 8.24 986 11.41 1288 14.28 15.68 17.00 18.18 19.28 21.34 23.18 25.10 2569 26.35 25.64 400 1.20 «264 475 668 846 1016 1°78 1332 1487 1619 1752 1877 20.02 22.98 23.92 25.98 2657 27.18 27.53 150 2.72 491 689 B76 1062 12.14 1376 153° 1871 1818 1943 206A 9989 7472 DA7O 9731 PAOA DRAt 300 262 S07 7.12 9.05 1082 1259 14.90 1582 17.22 18.89 2002 21.27 23.83 26.47 27.67 28.26 28.02 29.20 IV 1.00 «293-531 7.51 9.57 11.41 1892 16.09 1678 18.93 1987 21.27 22.60 2502 27.01 29.15 2959 30.10 90.10 1053.03 SU 7.73 9.86 1192 13./6 19.68 1/3! 19.06 2U5E 2203 23.40 2583 27.89 30.10 305¢ 31.21 3121 480 1.20 3.14 567 8.02 10.16 1222 14.28 1619 17.74 1965 2127 2282 2421 2672 28.85 31.13 3165 32.24 32.16 15) 324 SAT APA IDKP 1988 1477 1871 1A47 PAL 29N1 PA4A 2507 760 7973 AP18 3PBA BA27 33.27 2500 3.34 G05 8.54 10.80 1303 15.16 17.18 19.14 20.60 22.60 24.29 25.76 2848 30.78 3319 3371 34.20 34.30 4.00 3.99 647 876 1119 1340 15.63 17.86 1965 2142 23.26 2488 2655 20.07 31.21 33.34 3871 93.93] 93.49 1053.50 GSE 9.05 11.56 1384 16.12 18.25 2031 22.23 24.07 25.76 27.08 90.10 3298 34.52 34.96 36.11 | 34.67 BOD 1.20 «362 BSE 9.27 11.92 1443 16.71 18.84 2098 Z2G6 24.38 2664 2826 31.13 3941 39.70 36.14 36.38 | 39.84 150 375 681 964 1236 1487 17.22 19.50 21.71 23.77 25.59 27.45 29.15 3209 34.52 38.80 3724 37.54] 37.02 300 386 7.02 984 12866 153° 1781 20.09 2237 2481 2642 2834 30.10 33.19 3555 37.09 38.42 398.71 | 33.20 IV 1.00 3.98 7.18 10.16 19.93 1575 18.26 20.88 2296 25.10 27.08 28.92 30.60 9364 36.84 37.61 37.83) 37.39 1.05 4.07 «7.43 10.52 13.47 1627 18.84 21.34 2377 25.98 2804 90.03 31.72 9474 97.09 38.93 99.16] 36.71 peo 1.20 «4.21 7.65 1089 13.91 1678 190 22.08 24.98 25.94 2907 30.99 3283 3598 3835 4933 40.48] 40.04 180 4.34 7.95 11.26 1443 17.37 20.17 2289 2539 27.67 2996 3202 3393 3717 3960 41.58 4173] 41.29 22300 447 B17 11.63 1437 17.88 2083 2383 26.20 23.63 3091 33.05 35.03 3835 40.85 4291 43.06] 42.61 1.00 4.36 839 1162 1546 1898 21.27 2407 2672 29-5 3145 35.49 25.40 3842 40.48] 41.44 1.05 472 B61 12.22 76.75 18.92 22.01 24.96 27.60 90.°8 325G 94.67 26.65 99.74 41.95] 42.91 630 1.20 4.88 «891 1266 “627 19.58 22.82 2576 26.63 31.21 33.64 35.84 97.83 41.1¢ 49.95] 44.31 460 6.03 9.20 13.17 “678 20.17 2348 2664 26.51 32.24 3474 37.02 39.08 4247 44.68] 45.85 3.00 §.20 957 1347 7.37 20.90 24.21 2745 36.47 33.27 3584 36.20 40.33 43.79 46.15) 47.25 IV ‘area indicates mn. recommended pitch diam. T dynamizaily batanced sheaves are recommended. LENGTH CORRECTION FACTOR (C2) BELT NO 420 198 «144 «458 «178-180 «195-210 240-2770. «BON BBO 360-890 420. 480 540 600 PihTenaih G19" GG40 G747 4102 4480 4061 GAD 6420 8105 DA? 7700 e471 G200 GODS 10767 1a001 vaHOE 15800 Ge 0.86 0.87 0.90 092 093 0.94 096 088 1.00 103 1.05 1.07 1.09 1.11 1.42 1.43 1.18 1.20 Triple Double” Single strand strand kW 1000 700 500. 300 200 100 70 50 30 2q 07 05 03 02 0.4 0.07 0.05 0.03 SERVICE FACTOR Type ot Impact Machines Source of Power ‘Smooth Belt Conveyors with small load fluctuation, chain conveyors, centrifugal blowers, ordinary text machines, ordinary machines with small load fluctuation. Some impact Large impact (Centritugal compressors, marine engines, conveyors ‘with some load fluctuation, lautomatic furnaces, dryers, pulverizers, general machine too's, compressors, general |work machines, general paper mils Press, construction or mining machines, vibration machines, [oil well rigs rubber mixers, rolls, rll gangs, general machines with reverse or large impact loads, 15| 14 | 17 ROLLER CHAIN PROVISIONAL SELECTION TABLE kW 700 500: 300. 200. 100. 70 50 304 204 07 05 0.3 0.2: ot 0.07: 0.03: 0.02: strand kW 400 300 o7 05 03 02 0.4 0.07) 0.05 0.01 3 5 7 10 20 30 5070 100 200 500 1000 2000 5000 1000C 3 10 301 700 100 ©~=—- 7000