Answer Happy

Fig 11.17 Exercises 11.1 A full journal bearing of 100 mm in diameter and 150 mm in length supports a radial load of 5 000 N. The shaft speed is 500 r/min. The room temperature is 30°C and the bearing surface temperature is limited to 60°C. The bearing is of heavy construction and is well venti- lated. Assume the diametral clearance ratio to be 1 000 and select a suitable oil. [ISO VG 150] 11.2 A design for a full journal bearing calls for a dia- meter of 75 mm and a length of 130 mm to support a load of 20 kN. The bearing is to operate at a temperature not exceeding 65°C in an ambient temperature of 27°C. The oil viscosity grade is ISO VG 100 and has a density of 886 kg/m at a temperature of 20°C. The journal speed is 1 000 r/min. Determine the amount of artificial cooling required; this is to be supplied by an external cooler. Take D/C = 1 000. [221 W] =
11.3 A shaft running at 900 r/min is supported in a bear- ing of heavy construction which is 50 mm in diameter and 75 mm long. The bearing surface temperature is to be limited to 55°C, whilst the ambient temperature is 25°C. The oil has a kinematic viscosity of 12 mm'ls at the ope- rating temperature. The diametral clearance is 0,055 mm and the bearing is to operate without artificial cooling. Determine the permissible load and the power loss for the bearing. [3 996 N;43 W]