PTU B.Tech Mechanical Engineering 6th Semester May 2019 71185 DESIGN OF MACHINE ELEMENTS II Question Papers

PTU Punjab Technical University B-Tech May 2019 Question Papers 6th Semester Mechanical Engineering (MECH)

Roll No.
Total No. of Pages : 02
Total No. of Questions : 07
B.Tech (ME) (2011 Onwards) (Sem.?6)
DESIGN OF MACHINE ELEMENTS-II
Subject Code : BTME-601
M.Code : 71185
Time : 3 Hrs. Max. Marks : 60
INSTRUCTIONS TO CANDIDATES :
1.
SECTION-A is COMPULSORY consisting of TEN questions carrying T WO marks
each.
2.
SECTION-B contains SIX questions carrying TEN marks each and students have
to attempt any FOUR questions.
3. Use of a standard design data book is permitted.

SECTION-A

a) Differentiate between open belt and crossed belt drives.

b) Give any four advantages of V-belt over flat belt drive.

c) What is the main function of a flywheel in an engine?

d) Define coefficient of fluctuation of energy.

e) What is nipping in a leaf spring?

f) Name any two materials that are used for the lining of friction surfaces in clutches.

g) What is a self-energizing brake?

h) What are the advantages of involute gears over cycloidal gears?

i) Describe the 20? stub involute system of gear teeth.

j) What are journal bearings?

1 | M - 7 1 1 8 5

( S 1 7 ) - 1 0 2

SECTION-B
Q2. A centrifugal clutch is to be designed to transmit 15kW at 900 rpm. The shoes are four in
number and the speed at which the engagement begins is 3/4th of the running speed. The
inside radius of the pulley rim is 150 mm. Taking coefficient of friction as 0.25, find out
the mass and size of the shoes.
Q3. Discuss the different types of brakes giving at least one practical application for each
type.
Q4. An open belt 100 mm wide connects two pulleys mounted on parallel shafts with their
centres 2.4 m apart. The diameter of the larger pulley is 450 mm and that of smaller
pulley is 300 mm. Coefficient of friction is 0.3 and the maximum stress in the belt is
limited to 14 N/mm width. If the larger pulley rotates at 120 rpm, find the maximum
power that can be transmitted.
Q5. Design a helical compression spring for a maximum load of 1000 N and deflection of
25mm taking Wahl's factor into consideration. Assume spring index as 5, maximum
permissible shear stress for spring wire as 420 MPa and modulus of rigidity as
84 kN/mm2.
Q6. a) Mention four important types of gears and discuss their applications.

b) Explain the phenomenon of interference in involute gears. What are the conditions to
be satisfied in order to avoid interference?
Q7. Select a single row deep groove ball bearing for a radial load of 4000 N and an axial load
of 5000 N, operating at a speed of 1600 rpm for an average life of 5 years at 10 hours per