1. Select the most appropriate answer

When a shaft transmits power through gears, the shaft experiences

torsional stress alone

bending stress alone

constant bending and varying torsional stresses

constant torsional and varying bending stresses

Thickness of tooth is measured along:

root circle

pitch circle

addendum circle

dedendum circle

The range of pressure angle for spur gears is:

5 -15 degree

15 -20 degree

20 -30 degree

30 -40 degree

A worm has a lead angle of 22.5°. This corresponds to a helix angle of:

22.5 degree

45 degree

67.5 degree

90 degree

For buckling in a plane perpendicular to the plane of motion (about the the connecting rod is treated as a strut with:

both ends hinged

both ends fixed

one end fixed and the other end hinged

one end fixed and the other end free

Which tooth profile is preferred for very heavy load and to withstand wear resistance?

14.5 degree stub involute

14.5 degree full depth involute

20 degree sub involute

20 degree full depth involute

In the Lewis equation, the working stress depends upon:

material of the tooth only

pitch line velocity only

load conditions as well as material of the tooth

pitch line velocity, load conditions and material of the tooth

2. Determine the proper pitch, module, face, number of teeth and outside diameters of a pair of 200 involute full depth spur gears to transmit 120 kW, from a pinion running at 750 rev/min to a gear running at 140 rev/min. The service is intermittent with light shocks.

3. Design a pair of equal diameter, 20 degree stub tooth helical gears to transmit 38 kW with moderate shock at 1200 rev/min. The two shafts are parallel and 0·45 m apart. Each gear is to be of steel. Find the module and face width of the teeth.

4. Design a bearing and journal to support a load of 4500 N at 600 rev/min using a hardened steel journal and a bronze backed babbitt bearing. The bearing is lubricated by oil rings. Take room temperature as 21°C and the oil temperature as 80°C.

5. The spindle of a wood working machine revolves at 1000 rev/min and it is to be mounted on two single row radial ball bearings. The bearing is subjected to a radial load of 2250 N and a thrust load of 1900 N. Bearing is subjected to a radial load of 2250 N only. The machine is to be used approximately 8 hrs per day and an average service life of 10 years is desired. If the diameter of the spindle is not to exceed 300 mm, select the suitable bearings.

6. Design a worm gear set to transmit 15 kW from a shaft rotating at 1600 rpm to another shaft rotating at 80 rpm.

Discuss the various design considerations for an I.C. Engine.

List the various materials used for pistons. What are the functions of piston rings?