9_ch 07 Mechanical Design budynas_SM_ch07

9_ch 07 Mechanical Design budynas_SM_ch07 - can be lightly...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
186 Solutions Manual • Instructor’s Solution Manual to Accompany Mechanical Engineering Design k b = ± 1 0 . 3 ² 0 . 107 = 0 . 879 k c = k d = k e = k f = 1 S e = 0 . 869(0 . 879)(36) = 27 . 5 kpsi From Fig. A-15-8 with D / d = 1 . 25 and r / d = 0 . 03, K ts = 1 . 8 . From Fig. A-15-9 with D / d = 1 . 25 and r / d = 0 . 03, K t = 2 . 3 From Fig. 6-20 with r = 0 . 03 in, q = 0 . 65 . From Fig. 6-21 with r = 0 . 03 in, q s = 0 . 83 Eq. (6-31): K f = 1 + 0 . 65(2 . 3 1) = 1 . 85 K fs = 1 + 0 . 83(1 . 8 1) = 1 . 66 Using DE-elliptic, Eq. (7-11) with M m = T a = 0, 1 n = 16 π (1 3 ) ³ 4 ´ 1 . 85(360) 27 500 µ 2 + 3 ´ 1 . 66(192) 39 500 µ 2 1 / 2 n = 3 . 89 Perform a similar analysis at the profile keyway under the gear. The main problem with the design is the undersized shaft overhang with excessive slope at the gear. The use of crowned-teeth in the gears will eliminate this problem. 7-7 (a) One possible shaft layout is shown. Both bearings and the gear will be located against shoulders. The gear and the motor will transmit the torque through keys. The bearings
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: can be lightly pressed onto the shaft. The left bearing will locate the shaft in the housing, while the right bearing will oat in the housing. (b) From summing moments around the shaft axis, the tangential transmitted load through the gear will be W t = T / ( d / 2) = 2500 / (4 / 2) = 1250 lbf The radial component of gear force is related by the pressure angle. W r = W t tan = 1250 tan 20 = 455 lbf W = [ W 2 r + W 2 t ] 1 / 2 = (455 2 + 1250 2 ) 1 / 2 = 1330 lbf Reactions R A and R B , and the load W are all in the same plane. From force and moment balance, R A = 1330(2 / 11) = 242 lbf R B = 1330(9 / 11) = 1088 lbf M max = R A (9) = (242)(9) = 2178 lbf in...
View Full Document

This note was uploaded on 12/13/2011 for the course EML 3013 taught by Professor Shingley during the Fall '11 term at UNF.

Ask a homework question - tutors are online