Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 6th Semester (Sixth Semester) 2015-2016 NME 602EME 602 Machine Design Ii Question Paper
(Following Paper ID and Roll No. to be ?lled in your
Answer Books)
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B. TECH.
Theory Examination (Semester-VI) 2015-16
MACHINE DESIGN?II
Time : 3 Hours Max. Marks : 100
Note : 1. Assume any missing data suitably.
2. Use of design data book is allowed.
Section-A
l. Attempt all question : (2 x 10 = 20)
(a) 20?tooth, 8 pitch, 2.54-mm?wide, 20? pinion transmits
5 kw at 1725 rpm to aGO?tooth gear. Determine driving
force, separating force, and resultant force that would
act on mounting shafts.
(b) Whatdoyoulmdelstandbybeamsueng?lofgwtoom?
(c) De?ne worm gearing with applications?
(d) Classify the slidingconlactbea?ngintenns of thicknass
of layer of the lubricant between the bearing and
journal?
(1) , P.T.O.
1 106/W665/16625
(e)
(f)
(g)
(h)
(i)
Attempt any ?ve questions.
(a)
0))
Why is piston made light weight?
What kind of contact occurs between wonn and worm
wheel? How does it differ ?'om other types of gears?
What is SAE ?
De?ne Llo and L50 life for bearings.
What is the purpose of valve spn'ng?
What is herringbone helical gear?
Section-B
(5X10=50)
A pair of stmight teeth spur guns is to transmit 25 kW
when pinion rotates at 300 rpm. The velocity ratio is
1 : 3. The allowable static stresses for the pinion and
gear materials are 120 Mpa and 100 Mpa respectively.
The pinion has 15 teeth and its face width is 15 times
the module. Determine the module, face width and pitch
circle diameters of both the pinion and the gear from
standpoint of strength only, taking into consideration the
e?'ect of dynamic loading. Assume 20? full depth
involute pairs with ordinary cutting.
A steel pinion with 20? full depth involute teeth is
transmitting 7.5 kW power at 1000 rpm from an electric
(2)
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(C)
(d)
(e)
(0
motor. The starting torque of the motor is twice the
rated torque. The number of teeth on the pinion is 25,
while the module is 4. The face width 45 mm.
Assuming that velocity factor accounts for the dynamic
load, calculate
(1) Effective load on the gear tooth
(1i) Bending stress in the gear tooth.
A pair of 20? stub teeth spur gears is to transmit
20 kW . The pinion rotates at 500 rpm and the V.R. is
1 : 4. The allowable static stress for gear and pinion are
100 Mpa and 120 Mpa respectively. The pinion has 20
teeth and face width is 10 times the module. Design the
gear for static strength
Give the teiminology of helical gears with suitable
diagram. Also explain the forces on a helical gear tooth.
A journal bearing has ajoumal diameter of 50 mm and
the diameter of bushing is 50.1 mm. The bushing is 50
mmlongandhastosupponaloadofl KNataspeed
of1200 1pm. Detenninethe minimum oil ?lm thickness
and power loss for SAE 10 oil, assuming the oil ?lm
temperature to be 70?C.
A pair of helical gears is used to transmit 15 kW at
3000 rpm of the pinion. The teeth are 20? stub in
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(g)
(h)
diametric plane and the helix angle is 45?. The gear
and pinion have a pitch diameter of 320 and 80 mm
respectively. Both the gears are made of cast steel with
an allowable stress of100 Mpa. '[hemodulusofelasticity
for cast steel is 2 X 105 Mpa and its surface endurance
shength is 618 MPa. Suggest a suitable module and
face width for geax pair and check the strength of the
gear pair in wear.
The bore of a cylinder of the four stroke diesel engine
is 150mm. Themaximumgaspiessmeinsidethecylinder
is limitedto 3.5 Mpa. The cylinderheadismadeofgrey
cast iron FG 200 (out = 200 N/mm2) and the F08 is
5 .Determine the thickness of the cylinder head .Studs
is made of steel FeE 250 (cryt = 250 N/mm2) and the
F08 is 5. Calculate :
(1) Number of studs
(i1) Nominal diameter of studs
(iii) Pitch of studs
Determine the dimensions of cross-sections of the
connecting rod (l-section), for a diesel engine with the
following data :
(i) Cylinder bore = 100 mm
(i1) Length of connecting rod = 320 mm
(4)
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Attempt two question.
(iii) Maximum gas pressure = 2.45 Mpa
(iv) FOS against buckling failure = 5
Sec?on-C
(2x15=30)
3. The following data is given for a pair of parallel helical gears
made of steel :
Power transmitted = 20 kW, 11], = 720 rpm, zP = 35, zg = 70,
centre distance = 285 mm, normal module = 5 mm, b =
50 mm, normal pressure angle = 20?, S m = 600 N/mmz,
surface hardness number = 300 BI-IN, grade of machining =
6, Service factor = 1.25 Calculate :
(i)
(ii)
Gil)
6V)
(V)
(VI)
The helix angle;
Beam strength,
Wear strength,
Static load
The dynamic load by Buckingham's equation.
E??ective factor of safety against bending failure.
4. Design a high ef?ciency worm gear speed reducer to transmit
continuously the rated power output of 15 kW motor running
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at 1750 rpm. The steel worm having hardness 250 BHN is
integral with the motor sha?. The speed ratio is 10, while the
phosphor bronze gear should not have less than 40 mm.
5. Answer following in breif.
(i) Vntual no. of teeth is in helical gear.
(i1) Hydmstatic versus hydmdynamic baring.
(m) Reliability of anti?iction bearings.
(61
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This post was last modified on 29 January 2020