Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2017 Winter 7th Sem New 2171909 Machine Design Previous Question Paper
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2017
Subject Code: 2171909 Date:18/11/2017
Subject Name: Machine Design
Time: 10.30 AM to 01.30 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of design data book is permitted.
MARKS
Q.1 (a) Why dissimilar materials are used for worm and worm wheel?.
And explain the designation 4/29/10.6/2.5/50 used for the pair
of worm and worm gear.
03
(b) Explain the followings:
i) Interference and undercutting of gears
ii) Static and Dynamic load carrying capacity of
rolling contact bearings
04
(c) What are the major advantages of using geometric progression
of for speed regulation in a gear box?. And explain the design
procedure of 8-speed gear box for machine tool application
with the assumption of suitable and necessary data.
07
Q.2 (a) How are the gears classified?. Explain the role of pressure
angle in the gears.
03
(b) Explain different types of gear tooth failures 04
(c)
(c)
Design a spur gear drive to transmit 30 HP at 900 r.p.m. Speed
reduction ratio is 2.5 . Material for pinion and wheel are C.I
steel and Cast Iron respectively. Take pressure angle of 20
0
.
Design bending stress for pinion material is 85 N/mm
2
and
surface endurance limit for pinion material is 620 N/mm
2
.
Take the following data for the given gears:
Quality of the gears to be - Grade 12
Service factor,
OR
Design the bevel gear pair for the following specification using
Carl Barth velocity factor and wear consideration:
Power transmitted : 40 kW
Input speed : 360 rpm
Reduction ratio : 3
07
07
FirstRanker.com - FirstRanker's Choice
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2017
Subject Code: 2171909 Date:18/11/2017
Subject Name: Machine Design
Time: 10.30 AM to 01.30 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of design data book is permitted.
MARKS
Q.1 (a) Why dissimilar materials are used for worm and worm wheel?.
And explain the designation 4/29/10.6/2.5/50 used for the pair
of worm and worm gear.
03
(b) Explain the followings:
i) Interference and undercutting of gears
ii) Static and Dynamic load carrying capacity of
rolling contact bearings
04
(c) What are the major advantages of using geometric progression
of for speed regulation in a gear box?. And explain the design
procedure of 8-speed gear box for machine tool application
with the assumption of suitable and necessary data.
07
Q.2 (a) How are the gears classified?. Explain the role of pressure
angle in the gears.
03
(b) Explain different types of gear tooth failures 04
(c)
(c)
Design a spur gear drive to transmit 30 HP at 900 r.p.m. Speed
reduction ratio is 2.5 . Material for pinion and wheel are C.I
steel and Cast Iron respectively. Take pressure angle of 20
0
.
Design bending stress for pinion material is 85 N/mm
2
and
surface endurance limit for pinion material is 620 N/mm
2
.
Take the following data for the given gears:
Quality of the gears to be - Grade 12
Service factor,
OR
Design the bevel gear pair for the following specification using
Carl Barth velocity factor and wear consideration:
Power transmitted : 40 kW
Input speed : 360 rpm
Reduction ratio : 3
07
07
Shaft angle : 90
0
Application : Agitator
Q.3 (a) Give the classification of hydrodynamic bearings based on
lubrication.
03
(b) Explain the significance of L/D ratio and minimum oil-film
thickness in hydrodynamic bearings.
04
(c) The following data is given for a 360
0
hydrodynamic bearings:
Radial load : 3.1 kN
Journal diameter : 50 mm
Bearing length : 50 mm
Journal speed : 1440 rpm
Radial clearance : 50 microns
Viscosity of lubricant : 25 cP
Density of lubricant : 860 kg / m
3
Sp. Heat of lubricant : 1.76 kJ / kg
0
C
Assuming that the total heat generated in the bearing is carried
by the total oil flow in the bearing. Calculate:
i) Sommerfeld Number
ii) Minimum oil-film thickness
iii) The coefficient of friction
iv) The power lost in friction
v) The total flow rate of lubricant in liter /minute
vi) Side leakage
07
OR
Q.3 (a) What are the difference between Hydrodynamic and
Hydrostatic bearings.
03
(b) Derive the ? Petroff?s equation with assumptions made there
in.
04
(c) A Petroff?s sleeve bearing consists of a sleeve having a bore
diameter of 100.1 mm and a length of 100 mm. A shaft having
100 mm diameter supports a load of 4000 N. A shaft runs at
2880 r.p.m in the sleeve. If the frictional torque on the shaft is
10 N-m, find
i) The absolute viscosity of lubrication
ii) The bearing pressure
iii) The coefficient of friction and
iv) The power lost in bearing.
07
Q.4 (a) Define static and dynamic load carrying capacities of the
rolling contact bearings.
03
(b) Derive the equation for equivalent dynamic load for bearing
under cyclic loads.
04
FirstRanker.com - FirstRanker's Choice
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2017
Subject Code: 2171909 Date:18/11/2017
Subject Name: Machine Design
Time: 10.30 AM to 01.30 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of design data book is permitted.
MARKS
Q.1 (a) Why dissimilar materials are used for worm and worm wheel?.
And explain the designation 4/29/10.6/2.5/50 used for the pair
of worm and worm gear.
03
(b) Explain the followings:
i) Interference and undercutting of gears
ii) Static and Dynamic load carrying capacity of
rolling contact bearings
04
(c) What are the major advantages of using geometric progression
of for speed regulation in a gear box?. And explain the design
procedure of 8-speed gear box for machine tool application
with the assumption of suitable and necessary data.
07
Q.2 (a) How are the gears classified?. Explain the role of pressure
angle in the gears.
03
(b) Explain different types of gear tooth failures 04
(c)
(c)
Design a spur gear drive to transmit 30 HP at 900 r.p.m. Speed
reduction ratio is 2.5 . Material for pinion and wheel are C.I
steel and Cast Iron respectively. Take pressure angle of 20
0
.
Design bending stress for pinion material is 85 N/mm
2
and
surface endurance limit for pinion material is 620 N/mm
2
.
Take the following data for the given gears:
Quality of the gears to be - Grade 12
Service factor,
OR
Design the bevel gear pair for the following specification using
Carl Barth velocity factor and wear consideration:
Power transmitted : 40 kW
Input speed : 360 rpm
Reduction ratio : 3
07
07
Shaft angle : 90
0
Application : Agitator
Q.3 (a) Give the classification of hydrodynamic bearings based on
lubrication.
03
(b) Explain the significance of L/D ratio and minimum oil-film
thickness in hydrodynamic bearings.
04
(c) The following data is given for a 360
0
hydrodynamic bearings:
Radial load : 3.1 kN
Journal diameter : 50 mm
Bearing length : 50 mm
Journal speed : 1440 rpm
Radial clearance : 50 microns
Viscosity of lubricant : 25 cP
Density of lubricant : 860 kg / m
3
Sp. Heat of lubricant : 1.76 kJ / kg
0
C
Assuming that the total heat generated in the bearing is carried
by the total oil flow in the bearing. Calculate:
i) Sommerfeld Number
ii) Minimum oil-film thickness
iii) The coefficient of friction
iv) The power lost in friction
v) The total flow rate of lubricant in liter /minute
vi) Side leakage
07
OR
Q.3 (a) What are the difference between Hydrodynamic and
Hydrostatic bearings.
03
(b) Derive the ? Petroff?s equation with assumptions made there
in.
04
(c) A Petroff?s sleeve bearing consists of a sleeve having a bore
diameter of 100.1 mm and a length of 100 mm. A shaft having
100 mm diameter supports a load of 4000 N. A shaft runs at
2880 r.p.m in the sleeve. If the frictional torque on the shaft is
10 N-m, find
i) The absolute viscosity of lubrication
ii) The bearing pressure
iii) The coefficient of friction and
iv) The power lost in bearing.
07
Q.4 (a) Define static and dynamic load carrying capacities of the
rolling contact bearings.
03
(b) Derive the equation for equivalent dynamic load for bearing
under cyclic loads.
04
(c) A single-row deep groove ball bearing operated with the
following work cycle. If the expected life of the bearing is
13000 hours with reliability of 90%. Calculate the dynamic
load rating of the bearing and determine reliability of a system
consisting of four such bearings. The work cycle is as follows:
Gear Axial
load
(KN)
Radial
load
(KN)
Radial
Factor
Thrust
factor
Race
rotation
Cs N
rpm
% time
engage
d
I 1.5 5 0.56 1.1 Inner 1.25 960 30 %
II 0.73 3.7 0.56 1.3 Outer 1.4 1440 40 %
III - - - - Outer - 720 30 %
07
OR
Q.4 (a) Classify the rolling contact bearings. And explain how they are
designated according to ISI code of practice.
03
(b) Define the following terms:
(i) Rating life of rolling contact bearings
(ii) Median life
(iii) Equivalent dynamic load
(iv) Reliability of bearing
04
(c) Establish the following relationship between the life and
reliability of the rolling contact bearing;
07
Q.5 (a) Why the cylinder liners are being used in I.C.Engine?. What
are the desirable properties of the materials for the cylinder
liners.
03
(b) What are the functions of I.C.Engine piston ?. List the
elements involved in the I.C.Engine piston.
04
(c) The following data is given for the piston of a four-stroke
diesel engine:
Cylinder bore : 250 mm
Material of piston rings : Gray C.I.
Allowable tensile stress : 100 N / mm
2
Allowable radial pressure on
cylinder wall : 0.03 MPa
Thickness of piston head : 42 mm
No. of piston rings : 4
Calculate:
i) Radial width of the piston rings
ii) Axial thickness of the piston rings
iii) Gap between the free ends of the piston rings
before and after the assembly
iv) Width of the top land
07
FirstRanker.com - FirstRanker's Choice
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2017
Subject Code: 2171909 Date:18/11/2017
Subject Name: Machine Design
Time: 10.30 AM to 01.30 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of design data book is permitted.
MARKS
Q.1 (a) Why dissimilar materials are used for worm and worm wheel?.
And explain the designation 4/29/10.6/2.5/50 used for the pair
of worm and worm gear.
03
(b) Explain the followings:
i) Interference and undercutting of gears
ii) Static and Dynamic load carrying capacity of
rolling contact bearings
04
(c) What are the major advantages of using geometric progression
of for speed regulation in a gear box?. And explain the design
procedure of 8-speed gear box for machine tool application
with the assumption of suitable and necessary data.
07
Q.2 (a) How are the gears classified?. Explain the role of pressure
angle in the gears.
03
(b) Explain different types of gear tooth failures 04
(c)
(c)
Design a spur gear drive to transmit 30 HP at 900 r.p.m. Speed
reduction ratio is 2.5 . Material for pinion and wheel are C.I
steel and Cast Iron respectively. Take pressure angle of 20
0
.
Design bending stress for pinion material is 85 N/mm
2
and
surface endurance limit for pinion material is 620 N/mm
2
.
Take the following data for the given gears:
Quality of the gears to be - Grade 12
Service factor,
OR
Design the bevel gear pair for the following specification using
Carl Barth velocity factor and wear consideration:
Power transmitted : 40 kW
Input speed : 360 rpm
Reduction ratio : 3
07
07
Shaft angle : 90
0
Application : Agitator
Q.3 (a) Give the classification of hydrodynamic bearings based on
lubrication.
03
(b) Explain the significance of L/D ratio and minimum oil-film
thickness in hydrodynamic bearings.
04
(c) The following data is given for a 360
0
hydrodynamic bearings:
Radial load : 3.1 kN
Journal diameter : 50 mm
Bearing length : 50 mm
Journal speed : 1440 rpm
Radial clearance : 50 microns
Viscosity of lubricant : 25 cP
Density of lubricant : 860 kg / m
3
Sp. Heat of lubricant : 1.76 kJ / kg
0
C
Assuming that the total heat generated in the bearing is carried
by the total oil flow in the bearing. Calculate:
i) Sommerfeld Number
ii) Minimum oil-film thickness
iii) The coefficient of friction
iv) The power lost in friction
v) The total flow rate of lubricant in liter /minute
vi) Side leakage
07
OR
Q.3 (a) What are the difference between Hydrodynamic and
Hydrostatic bearings.
03
(b) Derive the ? Petroff?s equation with assumptions made there
in.
04
(c) A Petroff?s sleeve bearing consists of a sleeve having a bore
diameter of 100.1 mm and a length of 100 mm. A shaft having
100 mm diameter supports a load of 4000 N. A shaft runs at
2880 r.p.m in the sleeve. If the frictional torque on the shaft is
10 N-m, find
i) The absolute viscosity of lubrication
ii) The bearing pressure
iii) The coefficient of friction and
iv) The power lost in bearing.
07
Q.4 (a) Define static and dynamic load carrying capacities of the
rolling contact bearings.
03
(b) Derive the equation for equivalent dynamic load for bearing
under cyclic loads.
04
(c) A single-row deep groove ball bearing operated with the
following work cycle. If the expected life of the bearing is
13000 hours with reliability of 90%. Calculate the dynamic
load rating of the bearing and determine reliability of a system
consisting of four such bearings. The work cycle is as follows:
Gear Axial
load
(KN)
Radial
load
(KN)
Radial
Factor
Thrust
factor
Race
rotation
Cs N
rpm
% time
engage
d
I 1.5 5 0.56 1.1 Inner 1.25 960 30 %
II 0.73 3.7 0.56 1.3 Outer 1.4 1440 40 %
III - - - - Outer - 720 30 %
07
OR
Q.4 (a) Classify the rolling contact bearings. And explain how they are
designated according to ISI code of practice.
03
(b) Define the following terms:
(i) Rating life of rolling contact bearings
(ii) Median life
(iii) Equivalent dynamic load
(iv) Reliability of bearing
04
(c) Establish the following relationship between the life and
reliability of the rolling contact bearing;
07
Q.5 (a) Why the cylinder liners are being used in I.C.Engine?. What
are the desirable properties of the materials for the cylinder
liners.
03
(b) What are the functions of I.C.Engine piston ?. List the
elements involved in the I.C.Engine piston.
04
(c) The following data is given for the piston of a four-stroke
diesel engine:
Cylinder bore : 250 mm
Material of piston rings : Gray C.I.
Allowable tensile stress : 100 N / mm
2
Allowable radial pressure on
cylinder wall : 0.03 MPa
Thickness of piston head : 42 mm
No. of piston rings : 4
Calculate:
i) Radial width of the piston rings
ii) Axial thickness of the piston rings
iii) Gap between the free ends of the piston rings
before and after the assembly
iv) Width of the top land
07
v) Width of the ring grooves
vi) Thickness of the piston barrel
OR
Q.5 (a) What are the basic objectives of material handling systems?. 03
(b) What are the different types of ropes used in EOT cranes ?.
How they are designated and selected in the hoisting
mechanism.
04
(c) Design the following components of EOT cranes for the
following requirements:
Application : class ? II
Load to be lifted : 8 tones
Hoisting speed : 4 m / min
Maximum lift of the load : 12 m
(i) Select through design procedure a suitable wire rope
(ii) Sheave in a snatch block assembly of crane.
07
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This post was last modified on 20 February 2020