Ques

Q1. Below figure shows a two-stage gear reducer. Identical pairs of gears are used. (This enables input shaft a and output shaft c to be collinear, which facilitates machining of the housing.) Shaft b, called the countershaft, turns freely in bearings A and B, except for the gear-tooth forces. Select an appropriate bearing for A and B.

Q2. The rotating solid steel shaft is simply supported by bearings at points B and C and is driven by a gear (not shown) which meshes with the spur gear at D, which has a 150- mm pitch diameter. The force F from the drive gear acts at a pressure angle of 20°. The shaft transmits a torque to point A of TA = 340 Nm. Select an appropriate bearing for B and C.

Q3. Select an angular contact ball bearing for a radial load of 8000 N and an axial load of 9000 N, operating at a speed of 1200 rpm. For an average life of 4 years at 10 hours per day. Assume uniform and steady load. Suitable value of angle for angular may be assumed from design data handbook. Q4. Design a journal bearing for a centrifugal pump from the following data: Load on the journal = 20 000 N, Speed of the journal = 900 rpm. Type of oil is SAE 20. Ambient temperature of oil = 15.5°C. Assume the operating temperature in range of 550 C to 750C. Make the conclusion about the cooling of bearing based upon the calculation.

Q5. Select an appropriate bearing for A and B in the transmission shaft as shown in the figure below

Q6. Gears 3 and 4 act on the shaft shown in sketch b. The resultant gear force, PA = 2500 N, acts at an angle of 20° from the y-axis. Select appropriate bearings for O and B.

Q7. The gear train given below is used to drive a conveyor. Motor connected to input shaft is transmitting 20 KW at 1200 rpm. The gear ratio of gear A and B is 3.5 and gear ratio of C and D is 3. Design the pair of gears C and D by considering appropriate materials.

Q8. Devise a three stage reduction gear train for a recorder for a precision measuring instrument. The input is a shaft that rotates at exactly 1620 rpm. The output speed must be exactly 11.25 rpm. Gear ratio of gear A and B is 6, gear ratio of C and D is 6 and gear ratio of gear E and F is