STUPIDSID
1 (a)
Write a detailed note on selection of gear materials in detail.
5 M
1 (b)
Design (draw only structural diagram and speed chart ) a speed gearbox for the
following specifications for a head stock of a lathe machine:
Motor Power = 10 Kw;
Gearbox input shaft speed = 500 r.p.m.
Maximum speed = 630 r.p.m.;
Minimum speed = 100 r.p.m.
No. of step = 9
Motor Power = 10 Kw;
Gearbox input shaft speed = 500 r.p.m.
Maximum speed = 630 r.p.m.;
Minimum speed = 100 r.p.m.
No. of step = 9
9 M
2 (a)
Explain the effect of helix angle on power transmission capacity of helical gear. Also suggest the values of helix angle for helical gear.
5 M
Solve any one question from Q2(b) & Q2(c)
2 (b)
A pair of helical gears is used in a speed reducer, driven by an I.C. engine.
Pinion transmits 50 kW at 1000 r.p.m. The speed reduction is 4:1. Design the
gear pair assuming service load factor of 1.875 for medium shock condition and
continuous operation. Lewis's form factor Y=∏[0.154 ' 0.912/Z] and σen=
384 MPa. The other details are as below:
| Material | σb MPa | BHN |
| Pinion C30 forged steel | 175 | 150 |
| Gear cast steel | 140 | 180 |
9 M
2 (c)
The following data refers to a spur gear pair:
Service factor = 1.5
Dynamic load factor = 230 N/mm
Lewis's form factor Y=∏[0.154 ' 0.912/Z]
Velocity factor = 3/3+v
Wear factor = 0.156 [ BHN/100]2 MPa
Specify the kW capacity of the gear unit.
Service factor = 1.5
Dynamic load factor = 230 N/mm
Lewis's form factor Y=∏[0.154 ' 0.912/Z]
Velocity factor = 3/3+v
Wear factor = 0.156 [ BHN/100]2 MPa
Specify the kW capacity of the gear unit.
| Pinion | Gear | |
| Material | C-50 steel | C35 Mn 75 steel |
| Ultimate strength | 700 MPa | 600 MPa |
| BHN | 240 | 225 |
| Pitch diameter | 48 mm | 144 mm |
| No of teeth | 24 | 72 (20° full depth) |
| RPM | 1440 | 480 |
7 M
Solve any two question from Q3(a), Q3(b) & Q3(c), Q3(d)
3 (a)
Explain the thermal consideration in worm and worm gears in detail.
5 M
3 (b)
Design the pair of 90° straight bevel gear is used to transmit 7.5 kW from the
motor running at 1440 r.p.m. from the given data:
Speed reduction = 4:1
No of teeth on pinion = 18
Pressure angle = 20° full depth
Design stress for C.I. gears = 55 MPa
Stress concentration factor = 1.1
service load factor = 1.5
σes=550 MPa and take Ep=ES=2.0×105 N/mm2.
Speed reduction = 4:1
No of teeth on pinion = 18
Pressure angle = 20° full depth
Design stress for C.I. gears = 55 MPa
Stress concentration factor = 1.1
service load factor = 1.5
σes=550 MPa and take Ep=ES=2.0×105 N/mm2.
9 M
3 (c)
Explain the various gear tooth failures alongwith stating reasons and its remedies
in detail.
5 M
3 (d)
The following data refers to a worm gear:
Power = 15 kw
Speed of worm = 1200 rpm
Teeth on worm gear = 36 (20° full depth)
Tripple threaded worm
Axial pitch of the worm = 30 mm
Pitch diameter of worm = 60 mm
Coefficient of friction = 0.03
Find 1) helix angle of worm 2) speed ratio 3) center distance between two shafts 4) apparent stress in the worm gear 5) efficiency of drive.
Power = 15 kw
Speed of worm = 1200 rpm
Teeth on worm gear = 36 (20° full depth)
Tripple threaded worm
Axial pitch of the worm = 30 mm
Pitch diameter of worm = 60 mm
Coefficient of friction = 0.03
Find 1) helix angle of worm 2) speed ratio 3) center distance between two shafts 4) apparent stress in the worm gear 5) efficiency of drive.
9 M
Solve any two question from Q4(a), Q4(b) & Q4(c), Q4(d)
4 (a)
Explain the design of cylinder of an I.C. engine.
5 M
4 (b)
Design a connecting rod for a single cylinder I.C. engine from the following data:
Diameter of piston = 100 mm
Mass of reciprocating parts = 2.25 kg
Length of connecting rod = 300 mm;
Stroke = 125 mm
Speed = 1500 rpm
Compression ratio = 6
Factor of safety = 7
Maximum explosion pressure = 3.5 Mpa
For connecting rod material, yield stress in compression = 330 MPa.
Density of connecting rod material = 8000 kg/m3
Permissible whipping stress for connecting rod material = 20 Mpa.
Take size of connecting rod as 5t×4t×t.
Diameter of piston = 100 mm
Mass of reciprocating parts = 2.25 kg
Length of connecting rod = 300 mm;
Stroke = 125 mm
Speed = 1500 rpm
Compression ratio = 6
Factor of safety = 7
Maximum explosion pressure = 3.5 Mpa
For connecting rod material, yield stress in compression = 330 MPa.
Density of connecting rod material = 8000 kg/m3
Permissible whipping stress for connecting rod material = 20 Mpa.
Take size of connecting rod as 5t×4t×t.
9 M
4 (c)
Explain the valves gears mechanism used in an I.C. engine with neat sketch.
5 M
4 (d)
Design a cast iron piston for a four stroke I.C. engine from the following specification:
Cylinder Bore=110 mm
Stroke=120 mm
Maximum gas pressure=5N/mm2
Speed=2000 rev/min.
Indicated mean effective pressure=0.75 N/mm2
Fuel consumption=0.15 kg/BHP/hr,
Mechanical efficiency=80%
For C.I. piston, permissible tensile stress=35 N/mm2
HCV=42000 KJ/kg
K for C.I.=46.6 W/m °C.
Take Tc-Te=220°c
Permissible tensile stress for piston ring = 80 N/mm2
Permissible bending stress for pin = 85 N/mm2
Permissible bearing stress for pin = 20 N/mm2
Cylinder Bore=110 mm
Stroke=120 mm
Maximum gas pressure=5N/mm2
Speed=2000 rev/min.
Indicated mean effective pressure=0.75 N/mm2
Fuel consumption=0.15 kg/BHP/hr,
Mechanical efficiency=80%
For C.I. piston, permissible tensile stress=35 N/mm2
HCV=42000 KJ/kg
K for C.I.=46.6 W/m °C.
Take Tc-Te=220°c
Permissible tensile stress for piston ring = 80 N/mm2
Permissible bending stress for pin = 85 N/mm2
Permissible bearing stress for pin = 20 N/mm2
9 M
Solve any two question from Q5(a), Q5(b) & Q5(c), Q5(d)
5 (a)
Explain the design of belt conveyors / screw conveyors with a neat sketch.
5 M
5 (b)
Design the crane hook for a maximum load lifting capacity of 100 kN. The
material for hook is forged steel with permissible tensile stress 120 N/mm2.
Select the most suitable cross section for the hook.
9 M
5 (c)
Explain the basic Concepts of material handling system design in detail.
5 M
5 (d)
State the main parts commonly used in materials handling equipments alongwith neat sketch. Explain the design of drum and selection of suitable wire rope in detail.
9 M
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