**ANNA UNIVERSITY, CHENNAI 25**

**MODEL QUESTION PAPER**

**B.E. MECHANICAL ENGINEERING, VI SEMESTER**

**ME 342 – DESIGN OF TRANSMISSION SYSTEM**

*( Use of approved data book is permitted )*

TIME – 3 Hours MAXIMUM : 100 Marks

PART – A (10 x 2 = 20 Marks)

ANSWER ALL QUESTIONS

- What are the effects of centrifugal tension on flat belt.
- State any four advantages of V-belt drive over chain drive.
- What is meant by dynamic load in gears?

How it is taken care in the gear design?

- With the help of a sketch, indicate the normal pitch and axial

pitch in helical gear.

- Name two important modes of failure in gear.
- When do we use worm gear? Write any two applications of

worm-gear drive.

- What is the importance of saw-tooth diagram in the selection

of standard step ratio, in gear box design?

- What are the required properties of clutch material?
- Sketch a shoe brake and show the forces acting on the shoe.
- Distinguish between cross-lay and long lay wire ropes.

PART – B (5 x 16 = 80 Marks)

- In a spur gear drive for a rock crusher, the gears are made

of case hardened alloy steel. The pinion is transmitting 20 kW

at 1000 rpm with a gear ratio of 3.5. The gear is to work

8 hrs / day for 3 years. Design the drive (16 Marks)

- a) Design a fabric belt to transmit 10 kW at 450 rpm from an

engine to a line shaft at 1200 rpm. The diameter of the

engine pulley is 600 mm and the distance of the shaft

from the engine is 2 m. (16 Marks)

( OR )

b) Design a chain drive for a blower which is to run at 600 rpm.

Power available from a 10 HP motor at 1450 rpm. The motor

can be located at a distance not less than 700 mm. (16 Marks)

- a) A pair of helical gears subjected to heavy shock loading

is to transmit 37.5 kW at 1500 rpm of the pinion . The

speed reduction ratio is 4.25 and the helix angle is 15^{o}.

The service is continuous and the teeth are 20^{o}^{ } full depth

in the normal plane. Select suitable material and design

the gears. Calculate the major dimensions and sketch the

arrangement (16 Marks)

( OR )

b) A hardened steel worm rotates at 1440 rpm and transmit

15 kW to a phosphor bronze gear with gear ratio of 15.

Design the worm gear drive and sketch the arrangement.

What is the heat generated and the power loss? (16 Marks)

- a) Draw the ray diagram and kinematic lay out of a gear box

for an all geared headstock of a lathe. The maximum and

minimum speeds are to be 600 and 23 rpm respectively.

number of steps is 12 and drive is from a 3 kW electric

motor running at 1440 rpm. (16 Marks)

( OR )

b) Design the headstock gear box of a lathe having nine spindle

speeds ranging from 25 to 1000 rpm. The power of the machine

may be taken as 6 kW and speed of the motor is 1450 rpm.

Minimum number of teeth on the gear is to be 25.

a) Draw the speed diagram

b) Sketch the layout of the gear box.

c) Calculate the number of teeth on all gears. (16 Marks)

- a) In a band brake the drum diameter is 800 mm and the band

thickness is 5 mm. The brake facing has a coefficient of

friction of 0.25. The arc of contact is 250^{o}.^{ } This brake drum

is attached to a hoisting drum that sustains a rope load of

8 kN. The operating force has a moment arm of 1.5 m and

the band is attached 150 mm from the pivot point. Determine

a) the force required to just support the load

b) the required force when the direction is reversed, and

c) the width of steel band, limiting its tensile strength to

50 N/mm^{2} (16 Marks)

( OR )

b) A cone clutch has a cone angle of 11.5^{o}, a mean frictional

diameter of 320 mm, and face width of 60 mm. The clutch is

to transmit a torque of 200 Nm. The coefficient of friction

is 0.26. Find the activating force and pressure using the

assumption of uniform pressure. (16 Marks)