What is the general specification for bearing clearance?
2 Answers
Generally, it is 3-5 thousandths of an inch. Each manufacturer has different specifications. During normal operation of a steam turbine, the bearing temperature is around 85°C, and the general design is: axial thrust bearing alarm at 95°C, shutdown at 105°C; radial bearing alarm at 90°C, shutdown at 100°C. Specific details are as follows: 1. Material: In steam turbines, the bearing is one of the important components of the bearing assembly, being the part of the sliding bearing that contacts the shaft. It is very smooth and is usually made of wear-resistant materials such as bronze or anti-friction alloys, also known as a "bearing liner," shaped like a semi-cylindrical tile. 2. Main functions: To bear the force applied by the shaft neck, maintain stable oil film, ensure smooth operation of the bearing, and reduce friction loss. Bearings are divided into axial thrust bearings and radial bearings. Radial bearings support the rotor and rotating parts, while thrust bearings handle axial positioning and axial thrust, serving as important stationary components.
I'm a seasoned mechanic with decades of experience in this field, and bearing clearance is something that requires precision. The standard range is usually between 0.025 mm and 0.076 mm, but it depends on the engine model—gasoline engines may have slightly narrower clearances, while diesel engines can be a bit wider. If it's too tight, the bearings can overheat and develop scratches; if it's too loose, the engine will produce excessive noise, suffer from low oil pressure, and experience accelerated wear. Every time I disassemble the crankshaft, I meticulously measure with a micrometer—no room for carelessness. Only with the correct clearance can the oil film form properly, ensuring optimal lubrication and extending engine life. If car owners neglect this, minor issues can escalate into major repairs, costing a fortune. That's why I recommend checking it during regular maintenance.
