Problem-1

A section of commercial steel shafting 2.0 m long between bearings carries a 1000 N pulley at its midpoint, as shown in Figure. The pulley is keyed to the shaft and receives 30 kW at 150 rev/min, which is transmitted to a flexible coupling just outside the right bearing. The belt drive is horizontal and the sum of the belt tensions is 8000 N. Assume kt = kb =1.5. Calculate the necessary shaft diameter and determine the angle of twist between bearings. G = 80 GPa.

Problem 2:The figure shows the forces acting on a steel shaft carrying two gears. The gears are keyed to the shaft at B and D. A and C are journal bearing centers. 6 KW is transmitted at 650 rev/min of the shaft. The allowable stress for an unkeyed section is 80 MN/m2, and Kb = Kt = 1.5. a)- Sketch horizontal, vertical and resultant bending moment diagrams, shows values at change points. B)- Determine the necessary shaft diameter to the nearest mm. Indicate the critical section.

Problem-3

A 600 mm diameter pulley driven by a horizontal belt transmits power through a solid shaft to a 260 mm diameter pinion, which drives a mating gear. The pulley weighs 1200 N. The pinion has a pressure angle of 20o. The arrangement of elements, the belt tensions, and the components of the gear reactions on the pinion are indicated in the below Figure. Both pulley and pinion is keyed to the shaft. The shaft material is cold drawn AISI 1040. It is considered there is a minor shock during the operation when load applied. Design the necessary diameter along the shaft. Refer to the data given in the figure below.

Ft

Fr

Problem-4

The Figure below shows an arrangement for a motor and exciter with a pinion on the same shaft. The pinion drives a gear with the gear directly below the pinion. The motor develops 55 kW at 200 rpm. The exciter absorbs 5 kW, the remainder going to the pinion. The motor and the exciter are assembled to the shaft by means of a force fit while the pinion is keyed to the shaft. What is the required diameters of the shaft, if the shaft material is made of hot rolled AISI 1050 having an ultimate strength of 520 MPa and a yield point of 330 MPa. Use kb = kt = 1.5, the pressure angle of the gear is 20, and the desired reliability is 0.99.

Problem-5A machine shaft turning at 600 rev/min is supported on bearings 750 mm apart as shown in Figure below. A power of 15 kW is supplied to the shaft through a 450 mm pulley located 250 mm to the right of the right bearing. The power is transmitted from the shaft through a 200 mm spur gear located 250 mm to the right of the left bearing. The belt drive is at an angle of 60 ° above the horizontal. The pulley weighs 800 N to provide some flywheel effect. The ratio of the belt tensions is 3:1. The gear has a 20 tooth form and mates with another gear located directly above the shaft. If the shaft material selected has an ultimate strength of 500 MPa and a yield point of 310 MPa, determine the necessary shaft diameter using kb = kt = 1.0.