1. Preliminary judgment of not disassembling under operating conditions
Without dismantling the reducer, you can initially judge whether there is abnormal wear on the bearings and bearing housing holes by observing the operating status of the equipment:
1. Listen to the sound: If there are abnormal metal friction sounds, high-frequency "squeaking" sounds or "buzzing" sounds during operation, it may indicate that the bearing is short of oil or has been worn.
2. Measure temperature and vibration: Use instruments to detect vibration and temperature. If the vibration temperature rises abnormally, or the temperature at the bearing seat hole and journal is too high after shutdown, it indicates that there may be increased friction caused by wear.
3. Check the oil pressure and displacement: Observe whether the oil pressure of the equipment increases significantly and whether the axial displacement increases. These are signs of bearing damage or wear.
2. Precise inspection of appearance and dimensions after disassembly
When the equipment is shut down and disassembled, strict physical inspection of the bearing seat hole is required:
1. Appearance inspection: Clean the oil dirt and impurities on the surface of the hole, and carefully observe whether there are obvious scratches, grooves, material peeling or corrosion in the bearing contact area.
2. Roundness and cylindricity inspection: For hole parts, their roundness and cylindricity need to be inspected. You can use measuring tools such as vernier calipers, inside micrometers or cylinder gauges to measure at multiple points around the circumference and length of the hole to determine whether there is uneven wear.
3. Coaxiality inspection: There are often multiple bearing housing holes inside the reducer, and the coaxiality of the holes at both ends needs to be strictly inspected. If it is not concentric, the gear axis will be tilted after installation, destroying the center distance, causing damage to the machine parts or jamming of the bearings.
4. Fitting clearance inspection: You can use the feeler gauge insertion method or the fused wire extrusion method (pressed lead wire method) to indirectly obtain the fitting clearance between the bearing outer ring and the bearing seat hole to determine the degree of wear.
3. Baseline verification during the repair process
If the bearing seat hole is confirmed to be worn and prepared for repair (such as applying polymer material to scrape and repair), the accuracy also needs to be verified through a specific method during the repair process:
1. Find a benchmark: Before repairing, you need to measure the unworn part and use it as a benchmark to confirm the amount of wear.
2. Knife-edge ruler and feeler gauge inspection: When applying repair materials and scraping, it is necessary to use a knife-edge ruler and a feeler gauge for inspection. Follow the "no two" principle (that is, the feeler gauge inspection of the reference surface and the repair surface shall not exceed the specified number of wires, such as 2 wires) to ensure accurate restoration of dimensions and reduce subsequent metal fatigue wear.
3. Final size measurement: After the repair material has cured, use the inside micrometer again to measure critical dimensions to ensure they are restored to within the original tolerance range.
4. Advanced non-destructive testing
For reducers with highly integrated structures and compact internal spaces, if traditional disassembly inspection will destroy the original assembly accuracy and transmission balance, high-resolution industrial CT can be used for non-destructive inspection. This technology can penetrate complex structures, accurately obtain the internal geometric information of the bearing seat hole, quantitatively analyze deviations and evaluate remaining life.
