There are many reasons why the TP series worm gear reducer produces abnormal noise, and bearing damage is a common cause. If you want to accurately determine whether the abnormal noise comes from a bearing failure, you can make a comprehensive judgment from five aspects: listening to sound, measuring temperature, observing vibration, checking oil, and doing tests. You cannot make a conclusion based on one phenomenon alone.
1. Listen to the sound (acoustic judgment)
The reducer is operating normally, and the worm gear meshing sound is a uniform and low rustling sound. To check the abnormal noise of the bearing, you can use a listening stick or screwdriver to press it on the bearing end cover to isolate the environmental noise.
High-frequency squealing and hissing: the higher the speed, the greater the noise. Most of them are caused by excessive bearing clearance or insufficient lubrication, metal dry friction, and are early damage to the bearing.
Periodic metal knocking sound: The rhythm is synchronized with the rotation speed of the rotating shaft, and the "dang-dang" regular sound is usually caused by pitting corrosion of the bearing raceway and peeling of the inner ring.
Messy clicking sounds: no fixed period, irregular clicks and clatters, mostly caused by deformation and damage of the bearing cage and abnormal movement of the rolling elements.
Continuous harsh friction sound: Continuous metal friction noise and dull operation indicate large-scale damage to the bearing raceway and stuck rolling elements, which is a serious failure.
2. Measure temperature (temperature assists judgment)
If the bearing is damaged and the friction increases, abnormal heating will occur. Use an infrared thermometer to detect the surface of the bearing end cover.
Normal conditions: The temperature rise of the bearing end cover does not exceed the ambient temperature + 40°C.
Abnormality: The surface temperature exceeds 70°C, and it is too hot to touch for 3 seconds, indicating that the bearing lubrication fails, the rolling elements are damaged, or there is a sticking problem.
3. Look at vibration (vibration detection)
Bearing damage will destroy the rotation accuracy and cause vibration. You can use a vibration measuring pen to detect it.
Normal: vibration amplitude ≤0.1mm, no shaking visible to the naked eye.
Abnormality: The vibration amplitude exceeds 0.3mm, and the spectrum will have an obvious peak corresponding to the worm speed. As the speed and load increase, the vibration becomes larger.
4. Check the oil (physical evidence of wear)
Signs of bearing wear will be reflected in the lubricating oil. Take a small amount of oil and drop it on white paper or glass for observation.
Magnetic metal particles: The presence of silver-black debris in the oil that can be attracted by magnets means that the rolling elements and raceways are worn and peeled off; the presence of strips of metal debris larger than 1mm is basically a fracture of the cage.
The oil emulsifies and turns white: the oil turns milky white, which means the water inlet seal is damaged and the inside of the bearing has been corroded.
5. Do tests (working condition verification to exclude external factors)
Manual turning: Disengage the motor coupling and turn the worm input shaft manually. The rotation is not smooth, and the fixed position is stuck every time it rotates; the shaft is pushed and pulled axially, and the movement gap is greater than 0.5mm, indicating that the bearing raceway is damaged or the fit is loose.
No-load test: remove the load and run without load. If there is still abnormal noise and vibration under no load, the fault is in the internal bearing of the reducer; if it is normal under no load, there is a problem when there is a load, and the fault point is in the external load.
Current observation: Under rated load, the motor current increases by more than 20% compared to normal, and the speed decreases at the same time, which means the bearing friction resistance increases.
