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Silver Oak College of Engineering & Technology Aditya Silver Oak Institute of Technology

1. The document appears to be a midterm exam for a Machine Design course, consisting of 3 questions with multiple parts each. 2. Question 1 asks the student to (a) differentiate between structure and speed diagrams, and (b) calculate various parameters like Sommerfeld number and power lost for a hydrodynamic journal bearing given its specifications. 3. Question 2 gives two options - (a) design a crane hook with given material properties and load capacity, and explain hydrodynamic lubrication regimes and friction curves; or (b) sketch an EOT crane components and design a multi-speed gearbox for a machine tool with given motor speed. 4. Question 3 gives a similar

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191 views2 pages

Silver Oak College of Engineering & Technology Aditya Silver Oak Institute of Technology

1. The document appears to be a midterm exam for a Machine Design course, consisting of 3 questions with multiple parts each. 2. Question 1 asks the student to (a) differentiate between structure and speed diagrams, and (b) calculate various parameters like Sommerfeld number and power lost for a hydrodynamic journal bearing given its specifications. 3. Question 2 gives two options - (a) design a crane hook with given material properties and load capacity, and explain hydrodynamic lubrication regimes and friction curves; or (b) sketch an EOT crane components and design a multi-speed gearbox for a machine tool with given motor speed. 4. Question 3 gives a similar

Uploaded by

Shree Prajapati
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Enroll. No.

_____________

SILVER OAK COLLEGE OF ENGINEERING & TECHNOLOGY


ADITYA SILVER OAK INSTITUTE OF TECHNOLOGY
BE - SEMESTER–VII • MID SEMESTER-II EXAMINATION – WINTER 2018

SUBJECT: MACHINE DESIGN (2171909) (ME)

DATE: 03-10-2018 TIME: 10:00 am to 11:30 am TOTAL MARKS: 40


Instructions:
1. All the questions are compulsory.
2. Figures to the right indicate full marks.
3. Assume suitable data if required.
4. Use of PSG design data book or Bhandari Design data book is permitted. No other design
data books are permitted.

Q.1 (a) Differentiate between Structure Diagram and Speed Diagram. [03]
(b) A 360 degree hydrodynamic journal bearing has following characteristics [07]
Radial load = 3.2 kN
Diameter of Journal = 50 mm
Bearing length = 50 mm
Journal Speed = 1490 rpm
Radial Clearance = 50 microns
Viscosity of Lubricant = 25cP
Density of Lubricant = 860 kg/cubic metre
Specific heat of Lubricant = 1.75 KJ/kg0C
Assume the total heat generated in bearing is carried away by total oil flow in
bearing and calculate (a) Sommerfeld Number (b) Minimum oil film thickness
(c) Coefficient of friction (d) Power lost in friction (e) Total flow in lubricant.

Q.2 (a) Design the crane hook of a hoisting block for maximum load lifting capacity of [10]
10 tonnes. The material for hook is forged steel with permissible tensile stress of
120 N/mm2. Choose suitable cross section for the hook.
(b) Explain regimes of hydrodynamic lubrication. Explain performance of [05]
hydrodynamic bearings with curve of Coefficient of friction (f) V/s Bearing
characteristic Number (µ.ns/p).
OR
Q.2 (a) Draw a neat sketch of an EOT crane and list out its components. [05]
(b) A multispeed gearbox is to be designed for a small size general purpose machine [10]
tool for spindle speeds varying from 200 rpm to 2000 rpm. If the recommended
geometric progression ratio is as per R5. It is driven by a motor running at 2800
rpm. Draw (a) Candidate structure diagrams (b) Optimum structure diagram
(c) Optimum Speed Diagram and Ray Diagram (d) Kinematic diagram of
gearbox layout.
Q.3 (a) A 12 speed gear box is to be designed based on R10 series with a minimum [10]
spindle speed of 125 rpm. There are 3 stages and the second stage consists of
three speed steps. The electric motor connected to the gear box through a belt
drive runs at 1450 rpm. Using standard spindle speeds; and draw (i) the
structure diagram for the arrangement (ii) the optimum speed diagram and ray
diagram for the arrangement (iii) the gear box layout.
(b) Explain the following terms related to the Journal Bearing: (a) Viscosity Index [05]
(b) Bearing characteristic number (c) Sommerfeld Number (d) Bearing Modulus.
OR
Q.3 (a) Explain the designation of steel wire rope. [05]
(b) A Journal bearing has following characteristics: [10]
Radial load = 20 kN
Diameter of Journal = 100 mm
Speed of Journal = 900 rpm
Oil SAE10 with viscosity at 55 degree = 0.017 kg/msec
Ambient Temperature = 15.5 degrees
Maximum bearing pressure = 1.5 MPa
Permissible rise in oil temperature = 10 oC
Heat dissipation Coefficient = 1232 W/m2/oC
L/D ratio = 1.6
Design Parameter ZN/p = 28
Clearance ratio = 0.0013
Specific heat of oil = 1900 J/kg/ oC
Design the journal bearing for the above data.

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