The inspection methods for bearings

Inspection Methods for CARB Bearings

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1. Visual Inspection: Check the surface of the bearing for cracks, scratches, indentations, rust, peeling and folding. Examine the cage for deformation, wear, loose rivets or poor welding. Confirm that the bearing markings, including the model, specification, production batch and other information, are clear and complete.
2. Dimensional Accuracy Inspection: Use measuring tools such as vernier calipers and micrometers to measure the main dimensions of the bearing, such as the inner diameter, outer diameter and width, to ensure that the dimensional deviations are within the allowable range. Measure the relevant dimensions of the shaft and bearing housing that cooperate with the bearing to check whether the fit accuracy meets the requirements.
3. Clearance Inspection: The feel method can be used. Rotate the bearing by hand to feel whether it is stable and flexible, and whether there is any jamming. You can also shake the outer ring of the bearing by hand to roughly judge whether the radial clearance is within a reasonable range. Precise measurement can also be carried out with a feeler gauge or dial indicator. When using a feeler gauge, find the part of the bearing with the maximum load and insert the feeler gauge between the rolling element and the outer (inner) ring at 180° to it. The thickness of the feeler gauge that fits properly is the radial clearance of the bearing. When using a dial indicator, first set the dial indicator to zero, and then lift the outer ring of the bearing. The reading of the dial indicator is the radial clearance of the bearing.
4. Material Inspection: Analyze the chemical composition of the bearing material by using a spectrometer to ensure that the material meets the standard requirements. Use a hardness tester to detect the hardness of each part of the bearing to check whether it reaches the specified hardness range. Observe the metallographic structure of the bearing material through metallographic analysis equipment to judge whether it is uniform and whether there is any abnormal structure.
5. Dynamic Balance Inspection: Use a dynamic balance testing machine to detect the dynamic balance of the bearing and measure the unbalance of the bearing during rotation. According to the test results, adjust or correct the bearing, such as adding or removing counterweights, to reduce the unbalance of the bearing to within the allowable range.

Inspection Methods for Spherical Thrust Bearings

1. Visual Inspection: Check whether the raceway surface is smooth and free of wear, spalling, scratches, cracks and other damages. Examine the roller surface for wear, abrasion, cracks, spalling and other defects, and check whether the cylindricity and roundness of the roller meet the requirements. Check the cage for deformation, wear, fracture, loose rivets and other problems.
2. Dimensional Accuracy Inspection: Measure the dimensional parameters of the bearing, such as the inner diameter, outer diameter and height, and compare them with the standard values to ensure that the dimensional deviations are within the tolerance range. Check the dimensional accuracy of the shaft washer and housing washer, such as thickness, flatness and perpendicularity, to ensure their fit accuracy with the shaft and bearing housing.
3. Clearance Inspection: For the axial clearance inspection, the feel method can be used. When the shaft end is exposed, check the axial clearance of the bearing by hand, or indirectly judge by checking whether the shaft rotates flexibly. The measurement method can also be used. When using a feeler gauge, calculate the axial clearance according to the cone angle of the bearing and the thickness of the feeler gauge inserted. When using a dial indicator, move the shaft with a crowbar. The difference between the readings of the dial indicator when the shaft is in two extreme positions is the axial clearance of the bearing.
4. Installation Status Inspection: After installation, check whether the shaft washer and housing washer are installed correctly and whether there is any reversal or skew. Check the installation perpendicularity and concentricity of the bearing by fixing a dial indicator on the bearing housing or shaft, rotating the shaft or bearing, and observing the swing of the dial indicator pointer.