Example 4.10. A shaft is supported on bearings A and B, 800 mm between
centres. A 20° straight tooth spur gear having 600 mm pitch diameter, is
located 200 mm to the right of the left hand bearing A, and a 700 mm diameter
pulley is mounted 250 mm towards the left of bearing B. The gear is driven by
a pinion with a downward tangential force while the pulley drives a horizontal
belt having 180° angle of wrap. The pulley also serves as a flywheel and
weighs 2000 N. The maximum belt tension is 3000 N and the tension ratio is 3:
1. Determine the maximum bending moment and the necessary shaft diameter
if the allowable shear stress of the material is 40 MPa.
The space diagram of the shaft is shown in Fig. 4.2 (a).
The torque diagram is shown in Fig. 4.2 (b).
Assuming that the torque at D is equal to the torque at C, therefore the
tangential force acting on the gear C,
017
centres. A 20° straight tooth spur gear having 600 mm pitch diameter, is
located 200 mm to the right of the left hand bearing A, and a 700 mm diameter
pulley is mounted 250 mm towards the left of bearing B. The gear is driven by
a pinion with a downward tangential force while the pulley drives a horizontal
belt having 180° angle of wrap. The pulley also serves as a flywheel and
weighs 2000 N. The maximum belt tension is 3000 N and the tension ratio is 3:
1. Determine the maximum bending moment and the necessary shaft diameter
if the allowable shear stress of the material is 40 MPa.
The space diagram of the shaft is shown in Fig. 4.2 (a).
The torque diagram is shown in Fig. 4.2 (b).
Assuming that the torque at D is equal to the torque at C, therefore the
tangential force acting on the gear C,
017
