CWU225-2F is a circular cylindrical worm reducer. The box body is mostly made of gray cast iron. Breakage is often caused by overload impact, improper installation, casting defects or long-term vibration. The inspection needs to be comprehensively determined through three dimensions: static inspection during shutdown, dynamic inspection during operation, and disassembly depth inspection. The specific steps are as follows:
1. Shutdown static comprehensive inspection
1. Preliminary inspection of the appearance : Clean the oil, dust, and rust on the surface of the box, and wipe the entire machine casing with a clean rag. Pay special attention to the stress concentration areas such as the bearing seat, the joint surface of the upper and lower machine bases, around the oil drain/filler port, the roots of the heat sink, and the installation of anchor bolts. Visually observe whether there are obvious cracks, gaps, or missing pieces on the surface of the box. The cracks are usually accompanied by traces of rust and oil leakage. When the cracks penetrate the box, oil will continue to seep out, and there will be irregular linear rust marks at the micro-cracks.
2. Detailed inspection of key parts : Insert a feeler gauge into the joint surface of the upper and lower machine bases, and slide evenly along the joint surface to measure. The normal gap is ≤0.03mm. If the gap at a certain position is >0.1mm or the joint surface is partially misaligned or bulged, it may be caused by box deformation and rupture. Use a magnifying glass to look around the bolt holes of the bearing end cover, the outside of the worm shaft/worm gear shaft bearing seat, and the edges of the anchor bolt holes to look for hairline micro-cracks. Follow the direction of the oil stains on the surface of the box. If there is a rough metal fracture surface where the oil stains gather, there is a high probability that the box is broken and leaking oil.
3. Auxiliary tool detection : For micro-cracks that are difficult to detect visually, use a colored penetrant flaw detector to detect. The steps are to polish the area to be detected to a metallic luster and remove oil and rust, spray the penetrant and let it sit for 10-15 minutes, wipe the surface penetrant with a cleaning agent, and spray a developer. If a red linear trace appears, it is a crack, and the length and direction can be determined. Gently tap different parts of the box with a copper rod. The sound of a normal cast iron box will be crisp and even. If the sound is dull, hoarse or hollow in a certain area, there may be internal cracks or the expansion of blisters.
2. Run dynamic auxiliary troubleshooting
1. No-load operation inspection : Cut off the load connection, connect the motor power, and run without load for 10-15 minutes. Observe whether new oil leakage points appear on the surface of the box. If the leakage increases significantly during operation and there are no oil seals, gaskets and other seals at the leakage location, it can be determined that the box is broken. Monitor the operating noise. If there are abnormal metal friction sounds or popping sounds and the noise location is fixed on a certain side of the box, combined with the suspicious areas during shutdown inspection, it can help determine whether the cracks are rubbing against internal components.
2. Load operation inspection : Gradually load to the rated load and run for 30 minutes. Touch the suspicious parts of the box with your hands to feel whether there is any local heating abnormality. Friction heat is easily generated at cracks due to stress concentration. Observe the ground on which the reducer is installed. If there are oil stains on the anchor bolts, it may be that the bottom of the box is cracked. Use a vibrometer to measure the vibration intensity at different positions of the cabinet. If the vibration value in one area is much higher than that of other positions and the value fluctuates greatly, it may be that cracks cause the rigidity of the cabinet to decrease and trigger local resonance.
