Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 8th Sem New 2182004 Design Of Mechanisms Ii Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VIII (New) EXAMINATION ? WINTER 2019
Subject Code: 2182004 Date: 02/12/2019
Subject Name: Design of Mechanisms - II
Time: 02:30 PM TO 05:00 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 PSG design data book is permitted
Q:1 (a) Answer the following questions
1. Which of the following stresses are associated with the design of pins in
bushed pin type flexible coupling
(a) Torsional shear and
bending stress
(b) Crushing and bending stress
(c) Bending, bearing stress
and transverse shear
(d) Shear and crushing stress
2. The design calculations for members subjected to fluctuate loading with
the same factor of safety yield the most conservative estimate when
using
(a) Gerber relation (b) Soderberg relation
(c) Goodman relation (d) Modified Goodman relation
3. A wire rope is designated as 6 ? 19 standard hoisting. The number 6 ?
19 represent
(a) Number of strands ?
number of wires in each
strands
(b) Diameter in millimeter ?
length in meter
(c) Number of wires in each
strands ? number of
strands
(d) Wire diameter ? sheave
diameter
03
(b) Answer the following questions 04
1 For safe design of spur gear
(a) Wear strength < Dynamic
load
(b) Wear strength > Dynamic
load
(c) Beam strength >
Dynamic load
(d) Both (b) and (c)
2 In the assembly design of shaft, pulley and key, the weakest member is:
(a) Shaft (b) Pulley
(c) Key (d) None
3 The bearing characteristic number in hydrodynamic bearing depends on
(a) Length, width and load (b) Length, width and speed
(c) Viscosity, speed and load (d) Viscosity, speed and bearing
pressure
4 The life of a ball bearing is inversely proportional to
(a) (Load)
1/3
(b) (Load)
3
(c) (Load)
1/2
(d) None of the above
(c) Design a rigid flange coupling to transmit a torque of 250 N-m between two
coaxial shafts. The shaft is made of alloy steel, flanges out of cast iron and bolts
out of steel. Four bolts are used to couple the flanges. The shafts are keyed to the
flange hub. The permissible stresses are given below:
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Page 1 of 5
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VIII (New) EXAMINATION ? WINTER 2019
Subject Code: 2182004 Date: 02/12/2019
Subject Name: Design of Mechanisms - II
Time: 02:30 PM TO 05:00 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 PSG design data book is permitted
Q:1 (a) Answer the following questions
1. Which of the following stresses are associated with the design of pins in
bushed pin type flexible coupling
(a) Torsional shear and
bending stress
(b) Crushing and bending stress
(c) Bending, bearing stress
and transverse shear
(d) Shear and crushing stress
2. The design calculations for members subjected to fluctuate loading with
the same factor of safety yield the most conservative estimate when
using
(a) Gerber relation (b) Soderberg relation
(c) Goodman relation (d) Modified Goodman relation
3. A wire rope is designated as 6 ? 19 standard hoisting. The number 6 ?
19 represent
(a) Number of strands ?
number of wires in each
strands
(b) Diameter in millimeter ?
length in meter
(c) Number of wires in each
strands ? number of
strands
(d) Wire diameter ? sheave
diameter
03
(b) Answer the following questions 04
1 For safe design of spur gear
(a) Wear strength < Dynamic
load
(b) Wear strength > Dynamic
load
(c) Beam strength >
Dynamic load
(d) Both (b) and (c)
2 In the assembly design of shaft, pulley and key, the weakest member is:
(a) Shaft (b) Pulley
(c) Key (d) None
3 The bearing characteristic number in hydrodynamic bearing depends on
(a) Length, width and load (b) Length, width and speed
(c) Viscosity, speed and load (d) Viscosity, speed and bearing
pressure
4 The life of a ball bearing is inversely proportional to
(a) (Load)
1/3
(b) (Load)
3
(c) (Load)
1/2
(d) None of the above
(c) Design a rigid flange coupling to transmit a torque of 250 N-m between two
coaxial shafts. The shaft is made of alloy steel, flanges out of cast iron and bolts
out of steel. Four bolts are used to couple the flanges. The shafts are keyed to the
flange hub. The permissible stresses are given below:
Page 2 of 5
Shear stress on shaft =100 MPa
Bearing or crushing stress on shaft =250 MPa
Shear stress on keys =100 MPa
Crushing stress on keys =250 MPa
Shearing stress on cast iron =15 MPa
Shear stress on bolts =100 MPa
After designing the various elements, make a neat sketch of the assembly
indicating the important dimensions.
Q.2 (a) What do you understand by self locking of brake? Explain self locking condition
of block brake with suitable diagrams.
03
(b) How do you determine life of mechanical component which is subjected to
different stress levels for different parts of work cycle?
04
(c) A double shoe brake is shown in following figure. The brake drum rotates in
anticlockwise sense at 720 rpm, when the actuating force of 2.4 kN is applied.
The coefficient of friction between the blocks and drum is 0.25. Determine the
braking torque and the amount of heat generated.
07
OR
(c) A differential band brake is shown in following figure. The angle of contact is
280 deg. The brake is sustain a torque of 400 Nm. The band has compressed
woven lining and presses against cast iron drum of 0.375 m diameter. Assuming
coefficient of friction as 0.3:
1. Determine the necessary operating force P.
2. Find the width of steel band for thickness of 2 mm, assuming safe stress
in tension as 55 N/mm
2
.
3. Find the section of the brake lever.
07
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Page 1 of 5
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VIII (New) EXAMINATION ? WINTER 2019
Subject Code: 2182004 Date: 02/12/2019
Subject Name: Design of Mechanisms - II
Time: 02:30 PM TO 05:00 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 PSG design data book is permitted
Q:1 (a) Answer the following questions
1. Which of the following stresses are associated with the design of pins in
bushed pin type flexible coupling
(a) Torsional shear and
bending stress
(b) Crushing and bending stress
(c) Bending, bearing stress
and transverse shear
(d) Shear and crushing stress
2. The design calculations for members subjected to fluctuate loading with
the same factor of safety yield the most conservative estimate when
using
(a) Gerber relation (b) Soderberg relation
(c) Goodman relation (d) Modified Goodman relation
3. A wire rope is designated as 6 ? 19 standard hoisting. The number 6 ?
19 represent
(a) Number of strands ?
number of wires in each
strands
(b) Diameter in millimeter ?
length in meter
(c) Number of wires in each
strands ? number of
strands
(d) Wire diameter ? sheave
diameter
03
(b) Answer the following questions 04
1 For safe design of spur gear
(a) Wear strength < Dynamic
load
(b) Wear strength > Dynamic
load
(c) Beam strength >
Dynamic load
(d) Both (b) and (c)
2 In the assembly design of shaft, pulley and key, the weakest member is:
(a) Shaft (b) Pulley
(c) Key (d) None
3 The bearing characteristic number in hydrodynamic bearing depends on
(a) Length, width and load (b) Length, width and speed
(c) Viscosity, speed and load (d) Viscosity, speed and bearing
pressure
4 The life of a ball bearing is inversely proportional to
(a) (Load)
1/3
(b) (Load)
3
(c) (Load)
1/2
(d) None of the above
(c) Design a rigid flange coupling to transmit a torque of 250 N-m between two
coaxial shafts. The shaft is made of alloy steel, flanges out of cast iron and bolts
out of steel. Four bolts are used to couple the flanges. The shafts are keyed to the
flange hub. The permissible stresses are given below:
Page 2 of 5
Shear stress on shaft =100 MPa
Bearing or crushing stress on shaft =250 MPa
Shear stress on keys =100 MPa
Crushing stress on keys =250 MPa
Shearing stress on cast iron =15 MPa
Shear stress on bolts =100 MPa
After designing the various elements, make a neat sketch of the assembly
indicating the important dimensions.
Q.2 (a) What do you understand by self locking of brake? Explain self locking condition
of block brake with suitable diagrams.
03
(b) How do you determine life of mechanical component which is subjected to
different stress levels for different parts of work cycle?
04
(c) A double shoe brake is shown in following figure. The brake drum rotates in
anticlockwise sense at 720 rpm, when the actuating force of 2.4 kN is applied.
The coefficient of friction between the blocks and drum is 0.25. Determine the
braking torque and the amount of heat generated.
07
OR
(c) A differential band brake is shown in following figure. The angle of contact is
280 deg. The brake is sustain a torque of 400 Nm. The band has compressed
woven lining and presses against cast iron drum of 0.375 m diameter. Assuming
coefficient of friction as 0.3:
1. Determine the necessary operating force P.
2. Find the width of steel band for thickness of 2 mm, assuming safe stress
in tension as 55 N/mm
2
.
3. Find the section of the brake lever.
07
Page 3 of 5
Q.3 (a) Explain Goodman and modified Goodman diagrams for bending stresses. 03
(b) A mine hoist employs 6 ? 37 wire rope and has 6 falls of the rope. The maximum
lifting capacity is 25 kN. The maximum velocity of 2 m/s is attained by the hoist
trolley within 1.5 seconds. The dead weight accounts for 10% of the service load.
Overall efficiency of mine hoist is 95%. Design the rope for above application
using following data:
Breaking load = 470d
2
N, wire diameter = 0.045d mm, effective area of rope
=0.4d
2
mm
2
, minimum shaeve diameter = 25d mm, factor of safety = 5 and E =
8 ? 10
4
MPa. Where, d = diameter of rope in mm.
04
(c) 1. A section of C clamp is shown in following figure. Determine force P
which can be exerted by the screw if the maximum tensile stress in clamp
is not to exceed 140 N/mm
2
. Dimensions in figure are in mm.
? ?
? ?
i
o
i
i
n
R
R
e a
R
t R
e a B
h a t a B
R
log log ? ?
?
? ?
? ? ? ?
?
2. Differentiate straight beam and curved beam.
05
02
OR
Q:3 (a) Explain different loads and stresses induce in wire rope of hoisting mechanism. 03
(b) Explain different design steps to design hook for crane. 04
(c) Discuss various design steps for cross bar, pins and side links (hook supports) of
hoisting mechanism.
07
Q:4 (a) 1. What is hydrodynamic lubrication?
2. What is hydrostatic lubrication?
02
01
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Page 1 of 5
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VIII (New) EXAMINATION ? WINTER 2019
Subject Code: 2182004 Date: 02/12/2019
Subject Name: Design of Mechanisms - II
Time: 02:30 PM TO 05:00 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 PSG design data book is permitted
Q:1 (a) Answer the following questions
1. Which of the following stresses are associated with the design of pins in
bushed pin type flexible coupling
(a) Torsional shear and
bending stress
(b) Crushing and bending stress
(c) Bending, bearing stress
and transverse shear
(d) Shear and crushing stress
2. The design calculations for members subjected to fluctuate loading with
the same factor of safety yield the most conservative estimate when
using
(a) Gerber relation (b) Soderberg relation
(c) Goodman relation (d) Modified Goodman relation
3. A wire rope is designated as 6 ? 19 standard hoisting. The number 6 ?
19 represent
(a) Number of strands ?
number of wires in each
strands
(b) Diameter in millimeter ?
length in meter
(c) Number of wires in each
strands ? number of
strands
(d) Wire diameter ? sheave
diameter
03
(b) Answer the following questions 04
1 For safe design of spur gear
(a) Wear strength < Dynamic
load
(b) Wear strength > Dynamic
load
(c) Beam strength >
Dynamic load
(d) Both (b) and (c)
2 In the assembly design of shaft, pulley and key, the weakest member is:
(a) Shaft (b) Pulley
(c) Key (d) None
3 The bearing characteristic number in hydrodynamic bearing depends on
(a) Length, width and load (b) Length, width and speed
(c) Viscosity, speed and load (d) Viscosity, speed and bearing
pressure
4 The life of a ball bearing is inversely proportional to
(a) (Load)
1/3
(b) (Load)
3
(c) (Load)
1/2
(d) None of the above
(c) Design a rigid flange coupling to transmit a torque of 250 N-m between two
coaxial shafts. The shaft is made of alloy steel, flanges out of cast iron and bolts
out of steel. Four bolts are used to couple the flanges. The shafts are keyed to the
flange hub. The permissible stresses are given below:
Page 2 of 5
Shear stress on shaft =100 MPa
Bearing or crushing stress on shaft =250 MPa
Shear stress on keys =100 MPa
Crushing stress on keys =250 MPa
Shearing stress on cast iron =15 MPa
Shear stress on bolts =100 MPa
After designing the various elements, make a neat sketch of the assembly
indicating the important dimensions.
Q.2 (a) What do you understand by self locking of brake? Explain self locking condition
of block brake with suitable diagrams.
03
(b) How do you determine life of mechanical component which is subjected to
different stress levels for different parts of work cycle?
04
(c) A double shoe brake is shown in following figure. The brake drum rotates in
anticlockwise sense at 720 rpm, when the actuating force of 2.4 kN is applied.
The coefficient of friction between the blocks and drum is 0.25. Determine the
braking torque and the amount of heat generated.
07
OR
(c) A differential band brake is shown in following figure. The angle of contact is
280 deg. The brake is sustain a torque of 400 Nm. The band has compressed
woven lining and presses against cast iron drum of 0.375 m diameter. Assuming
coefficient of friction as 0.3:
1. Determine the necessary operating force P.
2. Find the width of steel band for thickness of 2 mm, assuming safe stress
in tension as 55 N/mm
2
.
3. Find the section of the brake lever.
07
Page 3 of 5
Q.3 (a) Explain Goodman and modified Goodman diagrams for bending stresses. 03
(b) A mine hoist employs 6 ? 37 wire rope and has 6 falls of the rope. The maximum
lifting capacity is 25 kN. The maximum velocity of 2 m/s is attained by the hoist
trolley within 1.5 seconds. The dead weight accounts for 10% of the service load.
Overall efficiency of mine hoist is 95%. Design the rope for above application
using following data:
Breaking load = 470d
2
N, wire diameter = 0.045d mm, effective area of rope
=0.4d
2
mm
2
, minimum shaeve diameter = 25d mm, factor of safety = 5 and E =
8 ? 10
4
MPa. Where, d = diameter of rope in mm.
04
(c) 1. A section of C clamp is shown in following figure. Determine force P
which can be exerted by the screw if the maximum tensile stress in clamp
is not to exceed 140 N/mm
2
. Dimensions in figure are in mm.
? ?
? ?
i
o
i
i
n
R
R
e a
R
t R
e a B
h a t a B
R
log log ? ?
?
? ?
? ? ? ?
?
2. Differentiate straight beam and curved beam.
05
02
OR
Q:3 (a) Explain different loads and stresses induce in wire rope of hoisting mechanism. 03
(b) Explain different design steps to design hook for crane. 04
(c) Discuss various design steps for cross bar, pins and side links (hook supports) of
hoisting mechanism.
07
Q:4 (a) 1. What is hydrodynamic lubrication?
2. What is hydrostatic lubrication?
02
01
Page 4 of 5
(b) Discuss the procedure used in designing cast iron pulley. 04
(c) A cantilever beam of circular cross section, made of cold drawn steel having an
ultimate tensile strength of 500 N/mm
2
and yield strength of 350 N/mm
2
is fixed
on one end as shown in following figure. The theoretical stress concentration
factor may be assumed as 1.42 and the notch sensitivity is 0.8. Assume surface
factor as 0.85 and size factor as 0.855. Determine life of the cantilever beam, if
factor of safety is 1.5 and reliability is 50%.
07
OR
Q:4 (a) What are four objectives of lubricants? 03
(b) Explain design for finite and infinite life of mechanical component under
complete reverse stress.
04
(c) Following data are relate to full hydrodynamic bearing:
Radial load = 3.2 kN
Journal speed = 1490 rpm
Journal diameter = 50 mm
Bearing length = 50 mm
Radial clearance = 0.05 mm
Viscosity of lubricant = 25 cP
Assuming that the total heat generated in the bearing is carried by the total oil
flow in the bearing, calculate:
1. Coefficient of friction
2. Power lost in friction
3. Minimum oil film thickness
4. Flow requirement in liters/min
5. Temperature rise
07
Q:5 (a) Derive the expression for beam strength of gear tooth. 03
(b) Discuss various gear tooth failure modes. 04
(c) A 60 mm diameter shaft of a machine operates continuously for 8 hrs daily. The
shaft bearing will be subjected to a varying load and speed cycle as follows:
Fraction of
cycle
Type of load Radial load
(kN)
Thrust load
(kN)
Speed (rpm)
0.1 Steady 4 2 1000
0.1 Light Shocks 2 2 1500
0.5 Light Shocks 5 2 1200
0.3 Steady 2.5 2 1500
The shock factors for ball bearing : Steady load = 1, Light shock = 1.5.
The details of ball bearing are : Bearing number 6412, C0 = 69500 N, C = 83000
N. Determine life of bearing.
07
Fa/C0 Fa/Fr > e e Fa/Fr ?e
X Y X Y
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Page 1 of 5
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VIII (New) EXAMINATION ? WINTER 2019
Subject Code: 2182004 Date: 02/12/2019
Subject Name: Design of Mechanisms - II
Time: 02:30 PM TO 05:00 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 PSG design data book is permitted
Q:1 (a) Answer the following questions
1. Which of the following stresses are associated with the design of pins in
bushed pin type flexible coupling
(a) Torsional shear and
bending stress
(b) Crushing and bending stress
(c) Bending, bearing stress
and transverse shear
(d) Shear and crushing stress
2. The design calculations for members subjected to fluctuate loading with
the same factor of safety yield the most conservative estimate when
using
(a) Gerber relation (b) Soderberg relation
(c) Goodman relation (d) Modified Goodman relation
3. A wire rope is designated as 6 ? 19 standard hoisting. The number 6 ?
19 represent
(a) Number of strands ?
number of wires in each
strands
(b) Diameter in millimeter ?
length in meter
(c) Number of wires in each
strands ? number of
strands
(d) Wire diameter ? sheave
diameter
03
(b) Answer the following questions 04
1 For safe design of spur gear
(a) Wear strength < Dynamic
load
(b) Wear strength > Dynamic
load
(c) Beam strength >
Dynamic load
(d) Both (b) and (c)
2 In the assembly design of shaft, pulley and key, the weakest member is:
(a) Shaft (b) Pulley
(c) Key (d) None
3 The bearing characteristic number in hydrodynamic bearing depends on
(a) Length, width and load (b) Length, width and speed
(c) Viscosity, speed and load (d) Viscosity, speed and bearing
pressure
4 The life of a ball bearing is inversely proportional to
(a) (Load)
1/3
(b) (Load)
3
(c) (Load)
1/2
(d) None of the above
(c) Design a rigid flange coupling to transmit a torque of 250 N-m between two
coaxial shafts. The shaft is made of alloy steel, flanges out of cast iron and bolts
out of steel. Four bolts are used to couple the flanges. The shafts are keyed to the
flange hub. The permissible stresses are given below:
Page 2 of 5
Shear stress on shaft =100 MPa
Bearing or crushing stress on shaft =250 MPa
Shear stress on keys =100 MPa
Crushing stress on keys =250 MPa
Shearing stress on cast iron =15 MPa
Shear stress on bolts =100 MPa
After designing the various elements, make a neat sketch of the assembly
indicating the important dimensions.
Q.2 (a) What do you understand by self locking of brake? Explain self locking condition
of block brake with suitable diagrams.
03
(b) How do you determine life of mechanical component which is subjected to
different stress levels for different parts of work cycle?
04
(c) A double shoe brake is shown in following figure. The brake drum rotates in
anticlockwise sense at 720 rpm, when the actuating force of 2.4 kN is applied.
The coefficient of friction between the blocks and drum is 0.25. Determine the
braking torque and the amount of heat generated.
07
OR
(c) A differential band brake is shown in following figure. The angle of contact is
280 deg. The brake is sustain a torque of 400 Nm. The band has compressed
woven lining and presses against cast iron drum of 0.375 m diameter. Assuming
coefficient of friction as 0.3:
1. Determine the necessary operating force P.
2. Find the width of steel band for thickness of 2 mm, assuming safe stress
in tension as 55 N/mm
2
.
3. Find the section of the brake lever.
07
Page 3 of 5
Q.3 (a) Explain Goodman and modified Goodman diagrams for bending stresses. 03
(b) A mine hoist employs 6 ? 37 wire rope and has 6 falls of the rope. The maximum
lifting capacity is 25 kN. The maximum velocity of 2 m/s is attained by the hoist
trolley within 1.5 seconds. The dead weight accounts for 10% of the service load.
Overall efficiency of mine hoist is 95%. Design the rope for above application
using following data:
Breaking load = 470d
2
N, wire diameter = 0.045d mm, effective area of rope
=0.4d
2
mm
2
, minimum shaeve diameter = 25d mm, factor of safety = 5 and E =
8 ? 10
4
MPa. Where, d = diameter of rope in mm.
04
(c) 1. A section of C clamp is shown in following figure. Determine force P
which can be exerted by the screw if the maximum tensile stress in clamp
is not to exceed 140 N/mm
2
. Dimensions in figure are in mm.
? ?
? ?
i
o
i
i
n
R
R
e a
R
t R
e a B
h a t a B
R
log log ? ?
?
? ?
? ? ? ?
?
2. Differentiate straight beam and curved beam.
05
02
OR
Q:3 (a) Explain different loads and stresses induce in wire rope of hoisting mechanism. 03
(b) Explain different design steps to design hook for crane. 04
(c) Discuss various design steps for cross bar, pins and side links (hook supports) of
hoisting mechanism.
07
Q:4 (a) 1. What is hydrodynamic lubrication?
2. What is hydrostatic lubrication?
02
01
Page 4 of 5
(b) Discuss the procedure used in designing cast iron pulley. 04
(c) A cantilever beam of circular cross section, made of cold drawn steel having an
ultimate tensile strength of 500 N/mm
2
and yield strength of 350 N/mm
2
is fixed
on one end as shown in following figure. The theoretical stress concentration
factor may be assumed as 1.42 and the notch sensitivity is 0.8. Assume surface
factor as 0.85 and size factor as 0.855. Determine life of the cantilever beam, if
factor of safety is 1.5 and reliability is 50%.
07
OR
Q:4 (a) What are four objectives of lubricants? 03
(b) Explain design for finite and infinite life of mechanical component under
complete reverse stress.
04
(c) Following data are relate to full hydrodynamic bearing:
Radial load = 3.2 kN
Journal speed = 1490 rpm
Journal diameter = 50 mm
Bearing length = 50 mm
Radial clearance = 0.05 mm
Viscosity of lubricant = 25 cP
Assuming that the total heat generated in the bearing is carried by the total oil
flow in the bearing, calculate:
1. Coefficient of friction
2. Power lost in friction
3. Minimum oil film thickness
4. Flow requirement in liters/min
5. Temperature rise
07
Q:5 (a) Derive the expression for beam strength of gear tooth. 03
(b) Discuss various gear tooth failure modes. 04
(c) A 60 mm diameter shaft of a machine operates continuously for 8 hrs daily. The
shaft bearing will be subjected to a varying load and speed cycle as follows:
Fraction of
cycle
Type of load Radial load
(kN)
Thrust load
(kN)
Speed (rpm)
0.1 Steady 4 2 1000
0.1 Light Shocks 2 2 1500
0.5 Light Shocks 5 2 1200
0.3 Steady 2.5 2 1500
The shock factors for ball bearing : Steady load = 1, Light shock = 1.5.
The details of ball bearing are : Bearing number 6412, C0 = 69500 N, C = 83000
N. Determine life of bearing.
07
Fa/C0 Fa/Fr > e e Fa/Fr ?e
X Y X Y
Page 5 of 5
0.014 0.56 2.3 0.19 1 2.3
0.028 0.56 1.99 0.22 1 1.99
0.056 0.56 1.71 0.26 1 1.71
OR
Q.5 (a) What do you understand by static load carrying and dynamic load carrying
capacity of ball bearing? Explain the criterion for static load carrying capacity
and dynamic load carrying capacity of ball bearing.
03
(b) Following data is given for a steel spur gear transmitting 7.5 kW power running
at 1440 rpm to a machine running at 480 rpm. Approximate center distance = 240
mm, Allowable bending stress for pinion and gear are 200 MPa and 160MPa
respectively. Surface hardness is 450 BHN. Tooth system is 20 ? full depths
involutes. Suggest size of the pinion and gear for this application.
04
(c) Design gear pair for above application. 07
? ?
? ?
p
p
s b p
t
dt 1/2
t
g
gp
2
es
pg
es
wp
0.912
Yp=0.154- (full depth)
Z
0.841
Yp=0.175- (stub gear)
Z
F f b Y m
C 11860 e
e 0.025
21v cb F
FF
21v cb F
2Z
Q
ZZ
f sin 11
k
1.4 E E
f 2.7459 BHN 68.65 MPa
F D Q k b
? ? ? ? ? ?
??
?
?
??
??
?
?
??
?
??
??
??
??
? ? ?
? ? ? ?
********
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This post was last modified on 20 February 2020