Design Project: Mechanical Engineering - Chain-Drives and Belt-Drives, Exams of Computer Aided Design (CAD)

Download Design Project: Mechanical Engineering - Chain-Drives and Belt-Drives and more Exams Computer Aided Design (CAD) in PDF only on Docsity! CORK INSTITUTE OF TECHNOLOGY Higher Certificate in Engineering in Mechanical Engineering – Award (NFQ Level 6) Autumn 2007 CAD & DESIGN (Paper 2 – Design Written) Time: 2 Hours Answer Question 1 (40 marks) and two other questions (30 marks each) Examiners: Dr. R.K. McMullan Mr. J. Connolly Dr. P. Delassus (1) Regarding chain-drives: • Explain the term Roller Chain • Sketch the elements that make up this type of chain • Indicate how the lubrication regime is selected • Explain how chain-drives are designed to fail. Why is this so? (14 marks) A series-wound DC motor drives a screw-type compressor. The motor produces 23kW @700rpm, and the compressor rated-speed is 250rpm. The distance between the shafts is 220mm, and the overall size of the drive must be kept less than 500mm. Design a chain-drive for the above application, using the tables provided. Clearly specify: • Service Factor • Chain size and pitch • Driven sprocket • Design Power • Number of strands • Lubrication method • Speed Ratio • Drive sprocket • Chain length (20 marks) (2) What effect does the type of prime mover and load have on the design of a belt-drive system? Give examples. (4 marks) List 5 advantages that a belt-drive has over other drive systems. (5 marks) List 5 applications for which a belt-drive would not be suitable, and concisely explain why. (5 marks) A 2-cylinder piston-pump whose design speed is 252rpm is driven by a 3-cylinder 16HP diesel engine for periods of up to 12 hours per day. The diesel runs at 640rpm, and the input and output shafts are spaced by 1.19m. Design a belt-drive for this application, using the tables provided. Clearly specify: • Service Factor • Sheave diameters • Belt-length correction factor • Belt Cross-section • Belt length and number • Arc-of-contact correction factor • Speed Ratio • Basic kW rating • Number of belts required (20 marks)