- Pls Help With Q2 4 Shaft Show Working This Was The Answer Given 2 4 D 50 Mm 1 (88.64 KiB) Viewed 24 times
- Pls Help With Q2 4 Shaft Show Working This Was The Answer Given 2 4 D 50 Mm 2 (65.8 KiB) Viewed 24 times
2.4) d = 50 mm
SECTION B (70 marks) Question 2 A conveyor belt is driven by a motor, via a compound gearbox and a belt drive. The gearbox has an efficiency of 90% and the speed reduction ratio 25:1. The belt drive has an efficiency of 96% and the speed reduction ratio 2:1. The conveyor drum requires a torque of 550 Nm at approximately 58 rpm. The belt conveyor operates for 12 hours per day and assume the load is gradually applied. Motor Coupling Input shaft T™ T 2.4 1 2 030 mm Gearbox 1₁ = 90%, VR₁ = 25:1 3 Belt Drive 12 = 96%, VR₂ = 2:1 Fig.2A Layout of two-stage gearbox Bearing A Figure 2.1 | | 1000N Tension due Output shaft XX to conveyor Belt 1500 N D ->> Conveyor Drum Drum Shaft Bearing B 1000 N ↓e 50mm 150mm 150mm Fig.28 Layout of Dum Shaft Shaft Assume forces acting on drum shaft is shown in the free body diagram Fig 2B. Given that the torque transmitted by the gear shaft is 581 Nm and the load is applied gradually, determine the shaft diameter (1st choice) assume commercial steel shaft and all components are keyed to the shaft.
1.1.4 Shaft Fall gall > o omax N d d = Mb = Mx + My 3 16k T It all 3 16 and and Itt all Or Tall = Tall > T d = Tmax N 3 32k+M no all (k₂M)² + (k₂T)²
Table 5-1 Allowable Shear Stress and Bending Stress values for commercial steel shafts With Keyway Tall = 40 MN/m² Gall = 80 MN/m² Allowable shear stress Allowable bending stress For other shafts, Tall = 1st 10 12 16 20 25 30 40 50 60 80 Preference 2nd Stationary Shafts Gradually applied loads Suddenly applied loads 15 35 45 55 70 90 Rotating shafts Gradually applied or steady loads 1.0 1.5 Suddenly applied loads with minor shock 1.5-2.0 1.0-1.5 Suddenly applied loads with heavy shock 1.5-3.0 1.5-3.0 Table 5-3 Preferred shaft diameters 25EGSD_Designtablev01.Dock Tmax N Table 5-2 Shock and fatigue factors and all = 3rd (14) (17) (18) (22) (28) (32) Without Keyway Tall = 55 MN/m² Oall = 100 MN/m² (42) (48) (65) (75) Omax N (85) Kb 1.0 1.5-2.0 1st 180 200 220 250 280 320 360 400 450 500 560 K₂ 630 1.0 1.5-2.0 Preference 2nd 240 260 300 340 380 420 480 530 600 3rd (170) (190) (210) (230) (440) (460) 24
Engineering System Design - Design Tables 100 120 140 d 10 12 14 16 18 20 22 25 28 30 (32) 35 38 40 (42) 45 (48) 50 55 60 (65) 70 (75) 110 12 0.5 130 150 16 1.0 (125) 1.0 0.5 160 1000 Note: a) Most bearing bore diameter comes in step of 5 mm; b) Shaft diameter smaller than 10 mm is also possible if suitable bearing is available. Table 5-4 Fillet radii for stepped shafts in Torsion Radii 20 1.5 1.0 1.0 bbin 25 1.5 | 1.5 1.5 1.0 D 30 2.0 1.5 710 1.5 1.0 800 900 40 2.0 2.0 2.0 1.5 1.5 1.0 50 2.5 2.5 670 2.5 2.5 2.0 1.5 1.0 750 850 950 60 3.0 3.0 3.0 2.5 5-Shaft 2.5 1.5 80 4.0 4.0 3.5 2.5 1.5