Bearing Identification
The identification of bearings is an important process in maintaining and troubleshooting rotating machinery. Bearing identification is used to determine manufacturer and bearing type, size and other important specifications.
Visual Inspection
The first step in bearing identification is visual inspection. Bearing type or manufacturer can sometimes be identified just by sight. OEM label or markings, if present, can greatly simplify the identification process by providing clear type or size information. When looking at a bearing, it can helpful to note the following features:
· Geometry or general shape of the bearing
· Dimensions or size
· Brand or company logo
· Metric or imperial markings denoting size or dimensions
· OEM markings or part number
· Rolling element type and material
Dimensions
Dimensions are essential to help identify a bearing correctly. Sizes are typically inscribed or marked with either ISO/IEC or other metric designations, or imperial measurements. Additionally, many bearings have a bore size stamped directly into them.
In cases where measurements must be taken, it is important to measure accurately so that the correct part can be ordered. Bore and shaft diameter should be measured with a micrometer or caliper, while outer diameter and overall width should be measured with a ruler or set of feeler gauges.
By noting these measurements, either an OEM part number, NSK/NTN/SKF bearing number or other recognised bearing supplier part number should be ascertainable.
Material
Material is another important aspect to consider when identifying bearings, as it often helps in determining application and estimated fatigue life. Bearing cages are most commonly made of brass or polyamide, or a steel such as carbon steel, stainless steel or a variation of chromium steel. Rolling elements are nearly always going to be made of either steel or ceramic.
Seal or Casing
The seal or casing surrounding a bearing can also provide a clue about what type or application the bearing could be used for. Seals can be single lip or a double lip constructed from polyacrylate, nitrile, polyurethane, fluorocarbon or other synthetic rubbers. Open and shielded bearings are also possible.
Call a Bearing Supplier
If identification is not possible after visual inspection and measurement, then the best course of action is to contact a bearing supplier or manufacturer. OEM or bearing type numbers are always useful and make the process simpler. Without this information, a supplier may be able to identify bearings using dimensions or other criteria such as dynamic load rating, radial load, thrust load, operating temperature and speed.
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In conclusion, bearing identification is a critical task in the maintenance and troubleshooting of rotating machinery. It is necessary to identify bearings in order to replace them with a suitable type and size, and to order the required number of spares in case of a future failure. Visual inspection, measurement, and calling a bearing supplier are the main methods of bearing identification. It is important to note any OEM or related markings on the bearing, as well as dimensions and other features that allow for accurate identification.
