Assignmnet No III ---- Machine Design II

 

Assignment No III

Machine Design - II

Topic: Design of Belt, Rope, Chain, Clutch, Brakes, Bearing, lubrication system and CAD

Date of issue: 9^th March, 2012                                       Last date of Submission: 23^rd March, 2012

1.      It is required to select a flat-belt drive for a compressor running at 720 rpm, which is driven by a 25 kW, 1440 rpm motor. Space is available for a centre distance of 3m. The belt is open type.

2.      Design a dry single plate friction clutch for following data:

P = 25 kW, N = 1440 rpm, Mean radius = 5 x face.

3.      Select a suitable chain drive to transmit 30 kW from an electric motor running at 1200 rpm to a line shaft running at 250 rpm. Motor shaft diameter is 60 mm and the centre distance is approximately 600 mm. Service is l0 hr/day, 6 days a week. Good lubrication condition is expected.

4.      A band brake has to absorb 4.5 k W at 150 rpm. For long life, the maximum pressure between lining and drum is 0.7MPa. The width of band is 50 mm and μ = 0.12. Find the angle of wrap if the brake drum diameter is 300 mm.

5.      A tentative design of a journal bearing result in a diameter of 75 mm and a length of 125 mm for supporting a load of 20 kN. The shaft runs at 1000 r.p.m. The bearing surface temperature is not to exceed75°C in a room temperature of 35°C. The oil used has an absolute viscosity of 0.01kg/m-s at the operating temperature. Determine the amount of artificial cooling required in watts. Assume d/c = 1000.

6.      Discuss the design procedure of lubrication system in transmission system.

7.      Describe the detail design process for computer aided design. Discuss how use of computers assist a designer in each stage of the design process with respect to reducing the time and providing wider spectrum to design solutions.

******