ME2352 Design of Transmission System Question paper

ME2352 Design of transmission system Anna University Question paper

B.E/B.TECH. DEGREE EXAMINATION ,NOV/DEC 2006
Sixth semester, Mechanical engineering
Design of transmission system


Time:3 Hrs
Maximum: 100 marks

PART A (10 X 2 =20)

1. What are the factors upon which the coefficient of friction between the belt and the pulleys depend?
2. In what ay the timming belt is suprior to ordinary V-belt.
3. What do you understand by simplex ,duplex and triplex chain?
4. State the law of gearing.
5. How does the function of a brake differ from that of a clutch?
6. Mention the important types of gears and discuss their applications.
7. State the advantage of herringbone gear.
8. What is a pressure angle? What is the effect of increasing in pressure angle ?
9. Name the different types of clutch.Why positive clutch is used?
10. Draw the ray diagram for a six speed gear box.

PART B ( 5 X 16 =80)
11. (a) A leather belt 9mm X 250 mm is used to drive a cast iron pulley 900 mm in diameter at 336 rpm.If the active arc on the smaller pulley is 20 degrees and stress in tight side is 2 MPa ,find the power capacity of the belt.The density of leathr may be taken as 980 Kg/m ^3 and coefficient of friction of leathre on cast iron is 0.35

OR

(b) Design a V belt drive and clculate the actual belt tension and average stress for the following data .Driven pulley diameter,D = 500 mm,Driver pulley diameter ,d = 150 mm ,center distance , C = 925 mm, speed n1 = 1000 rpm,n2 = 300 rpm and power ,P =7.5 kW.


12 (a) Design a chain drive to actuate a compressor from 15 kW eletric motor running at 100 rpm, hte compressor speed being 350 rpm.The minimum center distance is 500 mm.The compressor operates 16 hours per day.The chain tension may be adjusted by shifting the motor sides.

OR

(b) Design a straigth spur gear drive to transmit 8 kW.The pinion speed is 720 rpm and the speed ratio is 2.Both the gears are made of the same surface hardened carbon steel with 55 RC and core hardness less than 350 BHN .Ultimate strength is 720 N/mm ^2 and yield strength is 360 N/mm ^2

13 (a) Design a nine speed gearbox for a c machine to provide speeds ranging from 100 to 1500 rpm .The input is from a motor of 5 kW at 1440 rpm.Assume any alloy steel for the gear.

OR

(b) Design a pair bevel gear for two shafts whose axis are at rigth angles .Thepower transmitted is 25 Kw .The spedd of the pinion is 300 rpm and of the gear is 120 rpm.

14 (a) A single plate clutch ,effective on both sides ,is required to transmit 25 kW at 3000 rpm.Determine the outer and inner diameter of frictional surface if the coefficient of friction is 0.255,ratio of diameters is 1.25 and he maximum pressure is not exceeded 0.1 N/mm ^2 .Also determine the axial thrust to be provided by springs.Assume theory of uniform wear.

Or

(b) An engine developing 45kW at 1000 rpm id fitted with a cone clutch built inside the fly wheel.The cone has a face angle of 12.5 degree and a maximum mean diameter of 500 mm.The coefficient of friction is 0.2 .The normal pressure on the clutch face is not exceeded 0.1N/mm ^2 .Dtermine (i) The face width required (ii) the axial spring force necessary to engage the clutch.

15 (a) In a single block brake ,the diameter of the drum is 250 mm and th angle of contact is 90 degrees .If the operating force is 700 N is applied at the end of lever which is at 250 mm from the center of he brake block,The coefficient of friction between the drum and the lining is 0.35. Dtermine the torque that may be transmitted.Fulcrum is at 200 mm from the center of brake block with an offset 50 mm from the surface of contact.

OR

(b) Design a worm gear drive to transmit 22.5 kW at a worm speed of 1440 rpm.Velocity ratio 24:1 .An efficient of atleast 85% is desired .The temperature rise shoul be restricte to 40 degree C.Dtermine the required cooling area.

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