University: Mahatma Gandhi University
Course: B.Tech
Subject : Mechanical Engineering design of transmission elements
Year of Question Paper : 2014
B.TECH. DEGREE EXAMINATION, MAY 2014
Eighth Semester
Branch: Mechanical Engineering
DESIGN OF TRANSMISSION ELEMENTS (M)
(Regular/Supplementary)
Time: Three Hours Maximum Marks: 100
Answer one full question from each module
Use of Design Data Book is permitted. .
Missing Data may be assumed.
Module-1
1. A cone clutch has a cone angle of 300 and is used to transmit 10 kW at 1500rpm. The
width of the face is one-fourth of the mean diameter of friction lining. The normal intensity
of pressure between contact surfaces is 0.12 MPa and coefficient of friction is 0.2, assuming
uniform wear, design the clutch dimensions. (25 marks)
OR
2. A differential band brake has an operating lever 240mm long. The ends of the band are
attached at 40mm and 120mm on either side of the pivot. The drum diameter is 600mm.
Arc of contact is 3000
. Design the brake to absorb 15kWat 1200 rpm. (25 marks)
Module-2
3. (a)What is the difference between thick film and thin film lubrication?
(b)The following data is given for a 360° hydrodynamic bearing,
Radial load = 3.6 kN
Journal diameter = 55 mm
Bearing length = 27.5 mm
Radial clearance = 0.05 mm
Viscosity of lubricant = 25 CP.
Somerfield number of bearing is 0.0923.
Determine (i) Journal speed; (ii) Coefficient of friction; (iii) Power loss in friction; (iv) Flow
requirement; (v) Temperature rise. (20 marks)
OR
4. A journal bearing 160 mm long and 45 mm dia. supports a radial load of 8,000 N. The
shaft speed is 160 rpm; oil used is SAE 60 at 25° C inlet temperature. Using clearance ratio
600, find the rise in temperature, maximum films pressure and minimum film thickness.
(25 marks)
Module-3
5. (a) How do you specify the size of gear tooth? (5 marks)
(b) A pair of spur gear is to be designed. The pinion rotates at 800 rpm. and transmits 6 kW
to gear rotating at 200 rpm; Starting torque can be taken as 140% of rated torque for pinion
and gear allowable stress is 150 MPa. (20 marks)
.
OR
6. (a) Explain why helical gears are capable of transmitting, grater power at high speed as
compared to the spur gear. (5 marks)
(b) A pair of helical gears is to be designed to transmit 20 KW at a pinion speed of 1500
rpm. The velocity ratio is 2.5. Selecting suitable materials, determine the dimensions of the
gears. (20 marks)
Module-4
7. Design a flywheel for a single cylinder, four stroke vertical cylinder diesel engine
developing 4kW at 1500 rpm. Assume coefficient of speed fluctuation Cs=0.01. (25 marks)
OR
8. Design a piston for a four stroke diesel engine developing power at 1500 rpm. Other
related data are the following.
(1) Piston diameter= 87mm
(2) Length of the stroke = 96mm
(3) Mean effective pressure = 0.7 N/mm2
(4) bsfc = 0.26 kg/kWh
(5) L/r ratio= 4
(6) Heat conducted through the piston crown= 10% of heat generated during combustion.
(7) Calorific value of the fuel (CV) = 42 MJ/kg
Assume that the piston is made of aluminium alloy. (25 marks) ..
Course: B.Tech
Subject : Mechanical Engineering design of transmission elements
Year of Question Paper : 2014
B.TECH. DEGREE EXAMINATION, MAY 2014
Eighth Semester
Branch: Mechanical Engineering
DESIGN OF TRANSMISSION ELEMENTS (M)
(Regular/Supplementary)
Time: Three Hours Maximum Marks: 100
Answer one full question from each module
Use of Design Data Book is permitted. .
Missing Data may be assumed.
Module-1
1. A cone clutch has a cone angle of 300 and is used to transmit 10 kW at 1500rpm. The
width of the face is one-fourth of the mean diameter of friction lining. The normal intensity
of pressure between contact surfaces is 0.12 MPa and coefficient of friction is 0.2, assuming
uniform wear, design the clutch dimensions. (25 marks)
OR
2. A differential band brake has an operating lever 240mm long. The ends of the band are
attached at 40mm and 120mm on either side of the pivot. The drum diameter is 600mm.
Arc of contact is 3000
. Design the brake to absorb 15kWat 1200 rpm. (25 marks)
Module-2
3. (a)What is the difference between thick film and thin film lubrication?
(b)The following data is given for a 360° hydrodynamic bearing,
Radial load = 3.6 kN
Journal diameter = 55 mm
Bearing length = 27.5 mm
Radial clearance = 0.05 mm
Viscosity of lubricant = 25 CP.
Somerfield number of bearing is 0.0923.
Determine (i) Journal speed; (ii) Coefficient of friction; (iii) Power loss in friction; (iv) Flow
requirement; (v) Temperature rise. (20 marks)
OR
4. A journal bearing 160 mm long and 45 mm dia. supports a radial load of 8,000 N. The
shaft speed is 160 rpm; oil used is SAE 60 at 25° C inlet temperature. Using clearance ratio
600, find the rise in temperature, maximum films pressure and minimum film thickness.
(25 marks)
Module-3
5. (a) How do you specify the size of gear tooth? (5 marks)
(b) A pair of spur gear is to be designed. The pinion rotates at 800 rpm. and transmits 6 kW
to gear rotating at 200 rpm; Starting torque can be taken as 140% of rated torque for pinion
and gear allowable stress is 150 MPa. (20 marks)
.
OR
6. (a) Explain why helical gears are capable of transmitting, grater power at high speed as
compared to the spur gear. (5 marks)
(b) A pair of helical gears is to be designed to transmit 20 KW at a pinion speed of 1500
rpm. The velocity ratio is 2.5. Selecting suitable materials, determine the dimensions of the
gears. (20 marks)
Module-4
7. Design a flywheel for a single cylinder, four stroke vertical cylinder diesel engine
developing 4kW at 1500 rpm. Assume coefficient of speed fluctuation Cs=0.01. (25 marks)
OR
8. Design a piston for a four stroke diesel engine developing power at 1500 rpm. Other
related data are the following.
(1) Piston diameter= 87mm
(2) Length of the stroke = 96mm
(3) Mean effective pressure = 0.7 N/mm2
(4) bsfc = 0.26 kg/kWh
(5) L/r ratio= 4
(6) Heat conducted through the piston crown= 10% of heat generated during combustion.
(7) Calorific value of the fuel (CV) = 42 MJ/kg
Assume that the piston is made of aluminium alloy. (25 marks) ..
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