GTU 2171909 Machine Design Summer 2025 Question Paper & PDF

A spur gear drive is required to transmit a maximum power of 22.5 kW. The velocity ratio is 1:2 and r.p.m. of the pinion is 200. The approximate center distance between the shafts may be taken as 600 mm. The teeth has 20° stub involute profiles. The static stress for the gear material (which is cast iron) may be taken as 60 MPa and face width as 10 times the module. Find the module, face width and number of teeth on each gear. Check the design for dynamic and wear loads. The deformation or dynamic factor in the Buckingham equation may be taken as 80 and the material combination factor for the wear as 1.4.

Derive the equation for equivalent dynamic load for rolling contact bearing which are subjected to cyclic loads and speeds.

Design a machine tool gear box with the output speeds are 1000 r.p.m. maximum and 160 r.p.m. minimum. The gear box is a six speed gear box having structural formula (a) 2(3) 3(1) (b) 2(1) 3(2). Draw speed diagram and layout for above gear box.

Enumerate the steps for selection of rolling contact bearings for a particular application.

Load on the journal = 20 000 N; Speed of the journal = 900 r.p.m.; Type of oil is SAE 10 for which the absolute viscosity at 55°C = 0.017 kg/m-s; Ambient temperature of oil = 15.5°C; Maximum bearing pressure for the pump = 1.5 N/mm². Calculate also mass of the lubricating oil required for artificial cooling, if rise of temperature of oil be limited to 10°C. Heat dissipation coefficient = 1232 W/m²/°C.

Design a web (I-section), small and big end of the connecting rod for an I.C. engine running at 1800 r.p.m. and developing a maximum pressure of 3.15 N/mm². The diameter of the piston is 100 mm; mass of the reciprocating parts per cylinder 2.25 kg; length of connecting rod 380 mm; stroke of piston 190 mm and compression ratio 6: 1. Take a factor of safety of 6 for the design. Take length to diameter ratio for big end bearing as 1.3 and small end bearing as 2 and the corresponding bearing pressures as 10 N/mm² and 15 N/mm². The density of material of the rod may be taken as 8000 kg/m³ and the allowable stress in the bolts as 60 N/mm² and in cap as 80 N/mm².

Differentiate between thin and thick film lubrication in relation to journal bearing.

Determine a crane hook thickness and crane shank width to lift a load of 75000 N. Take factor of safety as 4 for a high alloy steel of yield strength as 342 N/mm². Assume the hook inner radius as 380 mm.