lecture #9 pulley recitation course name : design of machine elements course number: met 214
TRANSCRIPT
The shaft is driven at a uniform speed by pulley C. The shaft in turn drives pulley B & D. The diameter of pulleys B, C,D are 10 in, 12 in, 14 in respectively.Belt tensions are shown. The diameter of the shaft is 1 1/2inches.a) Calculate Belt tension F3.b) draw torque diagram starting from A and preceding to E. c) calculate max shear stress due to torsion
d) determine total bearing reactions at A & Ee) draw shear and moment diagrams in horizontal & vertical lanes.f) sketch composite moment diagramg) determine due to bending.h) Calculate using the 1927 shaft standard
max
Problem #2Given the information below and/or the information provided on problem #2 shown in the preceding diagram which includes pulley diameters, etc, find the quantities requested. Assume pulley D, when viewed from the end of shaft 2 looking toward load A, is rotating clockwise. HP of load A=5 HPSpeed of shaft 2, n2=150 rpma) Find torque associated with pulley D, i.e. TD=
b) Find torque associated with pulley B, i.e. TB=
c) Find speed of rotation of motor shaft, (rpm) i.e. find n1=
d) Find speed of rotation of shaft #3, i.e. n3=
Problem #2 continued:Assuming Tc=2000 in-lbe) Find torque associated with pulley A i.e. TA=
f) Find motor torque TM=
g) Find motor horse power HPm=
h) Identify on drawing of problem #2 the direction of rotation of each pulley in the system.
i) Given the FBD for the motor shaft and the axes for a torque diagram provided below, show all torques applied to the shaft and draw a torque diagram for the shaft on the axes provided
Example 2-8 : The carbon – steel countershaft shown in Fig. 2-25 is 25 mm in diameter and supports two V-belt pulleys. The countershaft runs at 1100 rpm. The belt tension on the slack side of pulley A is 15 percent of the tension on the tight side. Assume the shaft has a uniform diameter of 25mm.Assume pulley labeled with letters C & D is a driven pulley transferring power to the shaft. a) What amount of torque is transferred by the shaft between the pulleys?b) draw a torque diagramc) Compute the angle of twist of the shaft between the two pulleys as a function of G. d) Find the maximum torsional shear stress in the shaft e) additional questions appear on next page