Other Bachelor Degree- DESIGN OF TRANSMISSION SYSTEMS (Karunya University, Coimbatore-2012)
Saturday, 24 August 2013 10:36anudouglas
Karunya University
(Karunya Institute of Technology and Sciences)
(Declared as Deemed to be University under Sec.3 of the UGC Act, 1956)
Supplementary Examination – June 2012
Subject Title: DESIGN OF TRANSMISSION SYSTEMS Time : 3 hours
Subject Code: 09ME208 Maximum Marks: 100
Answer ALL questions
(Use of approved data books permitted)PART – A (10 x 1 = 10 MARKS)
1. The antifriction bearing are ________.
2. If the percentage slip is same on both the driving and driven pulley, then the speed ratio will be ________.
3. Factor of safety for fiber depends on velocity of rope that varies from ________.
4. Backlash in spur gear is ________.
5. A circle from which the tooth profile curve is generated is known as the ________.
6. When power is to be transmitted between two intersecting shafts, ________ are used.
7. A Geneva wheel has 6 slots. Driving crank radius is 100 mm. The distance between centres is ________.
8. A large number slots in a Geneva wheel ________.
9. The brake commonly used in automobiles is________.
10. Heat generated in a brake depends on ________.
PART – B (5 x 3 = 15 MARKS)
11. State the advantages and disadvantages of sliding contact bearings.
12. Specify the types of gear-failures.
13. What is law of gearing?
14. What is step ratio?
15. Why are V-threads not used in power screws?
PART – C (5 x 15 = 75 MARKS)
16. A 100 mm diameter full journal bearing supports a radial load of 5000 N. The bearing is 100 mm long and the shaft operates at 400 rpm. Assume permissible minimum film thickness of 0.025 mm and diametral clearance of 0.152 mm. Using Raimondi and Boyd curves determine (a) Viscosity of a suitable oil, (b) Coefficient of friction, (c) heat generated, (d) amount of oil pumped through the bearing, (e) amount of end leakage (amount of oil to be supplied to the bearing), (f) temperature rise of the oil flowing through the bearing.
(OR)
17. Design a V-belt drive and calculate the actual belt tensions and average stress for the following data. D= 500 mm, d = 150 mm, C = 925 mm, n1= 1000 rpm, n2 = 300 rpm and P = 7.5 kW.
18. Calculate a straight spur gear drive. Transmitted power 8 kW. Pinion speed 764 rpm. Speed ratio = 2. The Gars are to be made of C45. Life is to be 10,000 hours.
(OR)
19. A pair of helical gear subjected to moderate shock loading is to transmit 37.5 kW at 1750 rpm of the pinion. The speed reduction ratio is 4.25 and the helix angle is 150. The service is continuous and the teeth are 200 FD in the normal plane. Design the gears, assuming a life of 10,000 hours.
[P.T.O]
20. Design a bevel gear drive to transmit 3.5 kW. Speed ratio = 4. Driving shaft speed = 200 rpm. The drive is non-reversible. Pinion is of steel and wheel of CI. Assume a life of 25000 hours.
(OR)
21. Design a worm gear drive to transmit 22.5 kW at a worm speed of 1440 rpm. Velocity ratio is 24:1. An efficiency of atleast 85% is desired. The temperature rise should be restricted to
40°C.
22. Draw the kinematic arrangement and ray diagram of a six speed gear box having output speeds ranging from 460 – 1400 rpm.
(OR)
23. A machine tool gear box powered by 11 kW, 970 rpm motor is to give 14 spindle speeds ranging from 20 to 400 rpm. Draw the kinematic arrangement and the speed chart.
24. Design a ratchet wheel for a winch. Data given: Braking torque = 160 Nm: Brake drum diameter = 400 mm.
(OR)
25. A differential band brake is to be designed for a winch lifting a load of 45 kN through a rope wound round a barrel of 500 mm diameter. The brake drum to be keyed to the same shaft is to be 600 mm in diameter and the angle of lap of the brake band over the drum is 250o approximately. Determine the width and thickness of the band. Operating arms of the brake are 40 mm and 200 mm. Operating lever is 1.5 m long.
| Earning: ₹ 4.25/- |
