5) Design ೩ spur gear oftwo shafts transmitting 30 kW power at 3000 rpm of the driver. "Ihe 1018
number of teeth on the driving gear is 30 and that of driven is 90. The tooth system is 20 ° involute
and the diameter is made of casi iron and pinion is made of C40 steel. (9 Marks)

6) a) Explain law of gearing. (2 Marks)

0) Design a helical gear to transmit 25 hp at 1440 rpm of the pinion. The gear ratio is I .*3, helix angle
25 9 and having full depth tooth system. Pinion is having 24 teeth and is made of steel and gear is
made of CI grade 25. (7 Marks)

Part C

7) A hardened worm rotates at 1440 rpm and transmits 1 2 kW to a phosphorous bronze gear. 11൨൦
speed of the worm wheel should be 60 + 3% rpm. Design the worm gear drive if an efficiency of at
least 82% is desired. (12 Marks)

8) A nine speed gear box used as a head stock gear box of a turret late is to provide a speed range of

180 rpm to 1800 rpm. Using standard step ratio draw the ray diagram and kinematic layout. Also
find the number of teeth on all gears. (12 Marks)

9) a) With a neat sketch explain the working of a constant mesh gear box. (6 Marks)

b) A sliding mesh gear box is to be used for 4 forward and I reverse speeds. First gear speed ratio is
5.5 and reverse gear speed ratio is 5.8. Clutch gear on clutch shaft and gear (in constant mesh) on
lay shaft has speed ratio of 2. Calculate the number of teeth on all gears. Assume that the minimum
number of teeth on any gear should not be less than 1 8. Calculate the actual gear ratios. (6
Marks)