How to check whether the CWU225-2F reducer has a box rupture
CWU225-2F is a circular arc cylindrical worm gear reducer, with a housing mostly made of gray cast iron material. Cracks are often caused by overload impact, improper installation, casting defects, or long-term vibration. Inspection requires a comprehensive judgment from three dimensions: static inspection during shutdown, dynamic investigation during operation, and depth inspection during disassembly. The specific steps are as follows:
1、 Static comprehensive inspection during shutdown
1. Preliminary appearance inspection: Clean the oil stains, dust, and rust on the surface of the box, wipe the entire machine shell with a clean cloth, and pay attention to stress concentration areas such as near the bearing seat, the joint surface between the upper and lower machine bases, the periphery of the oil drain/filling port, the root of the heat sink, and the installation of the anchor bolts. Visually observe whether there are obvious cracks, gaps, or falling pieces on the surface of the box. The cracked area is usually accompanied by rust and oil leakage marks. When the crack penetrates the box, oil will continue to leak out, and irregular linear rust marks will appear at the micro crack location.
2. Key part detail inspection: Insert a feeler gauge into the joint surface of the upper and lower machine bases, slide evenly along the joint surface for measurement, with a normal gap of ≤ 0.03mm. If the gap at a certain position is greater than 0.1mm or the joint surface is partially misaligned or protruding, it may be due to deformation and rupture of the box body. Use a magnifying glass to observe the surroundings of the bearing end cap bolt hole, the outer side of the worm shaft/worm gear shaft bearing seat, and the edge of the anchor bolt hole, and search for hair like microcracks. Tracing the direction of the oil stains on the surface of the box, if there is a rough metal fracture surface at the location where the oil stains accumulate, it is highly likely that the box has ruptured and leaked oil.
3. Auxiliary tool detection: For micro cracks that are difficult to visually detect, dye penetrant inspection agent is used for detection. The steps are to polish the area to a metallic luster and remove oil and rust, spray penetrant and let it stand for 10-15 minutes, wipe the surface penetrant with cleaning agent, and spray imaging agent. If there are red linear marks, it is a crack, and the length and direction can be determined. Gently tap different parts of the box with a copper rod. A normal cast iron box produces a clear and even tapping sound. If the sound in a certain area is dull, hoarse, or hollow, there may be internal cracks or sand holes expanding.
2、 Run dynamic auxiliary troubleshooting
1. No load operation inspection: Cut off the load connection, connect the motor power supply, run without load for 10-15 minutes, and observe whether there are new oil leakage points on the surface of the box. If the leakage amount increases significantly during operation and there are no seals such as oil seals or gaskets at the leakage location, it can be determined that the box is broken. Monitor the running noise, and if there are abnormal metal friction or cracking sounds and the noise is fixed on one side of the box, combined with the suspicious area of the shutdown inspection, assist in determining whether the crack is rubbing against the internal components.
2. Load operation inspection: Gradually load to the rated load and run for 30 minutes. Touch the suspicious part of the box with your hand to feel if there is any local heating abnormality. Cracks are prone to frictional heat due to stress concentration. Observe the installation foundation ground of the gearbox. If there are oil stains on the anchor bolts, it may be a crack at the bottom of the box. Measure the vibration intensity at different positions of the box with a vibration meter. If the vibration value in a certain area far exceeds that of other positions and fluctuates greatly, it may be caused by cracks leading to a decrease in the stiffness of the box and causing local resonance.
