What are the early signs of damage in the B3SH8 gearbox
1、 Signs of vibration and abnormal noise
Abnormal noise associated with rotational speed: High frequency whistling occurs when the rotational speed suddenly increases, accompanied by periodic knocking sound caused by axial movement of the shaft system, which is an early signal of bearing preload failure and shaft alignment deviation.
Vibration spectrum variation: The gear meshing frequency and its harmonic amplitude increase by 30% -80%, and the sideband significantly expands; During moderate wear, the amplitude of radial vibration increases by 50% -80% compared to the normal value, and the frequency spectrum shows a significant increase in "burrs" around the meshing frequency, with a disordered morphology.
The vibration value gradually exceeds the standard: the effective value of the vibration velocity at the bearing seat position gradually exceeds the industrial safety limit of 2.8mm/s and continues to approach the overhaul threshold of 4.5mm/s.
2、 Abnormal signs of temperature and temperature rise
Abnormal acceleration of temperature rise rate: Under rated operating conditions, the oil temperature rises by 5-10 ℃ per hour, accompanied by dry friction noise from "rustling" to "creaking", indicating insufficient oil supply to the lubrication system and imminent rupture of the oil film.
Excessive temperature difference: If the temperature difference between each bearing seat is greater than 8 ℃, or if the oil temperature suddenly rises by 10 ℃ in a short period of time, it indicates uneven internal load and abnormal contact of local friction pairs.
Continuous high temperature: After excluding external factors such as cooler blockage and incorrect selection of lubricating oil, the lubricating oil temperature continues to exceed 90 ℃ and the shell temperature exceeds 85 ℃, which is a typical warning before tooth surface bonding and bearing burnout.
3、 Signs of abnormal oil condition
Abnormal increase in metal abrasive particles: Metal wear particles larger than 15 μ m appeared for the first time in oil ferrography analysis, and the iron content gradually increased towards the overhaul threshold of 500ppm, indicating that the tooth surface or bearing has entered the accelerated wear stage.
Rapid deterioration of oil performance: The viscosity change rate of lubricating oil exceeds 20%, the moisture content exceeds 500ppm, and even after changing the oil, it quickly turns black and dirty in a short period of time, indicating that the wear debris generated by internal wear continues to contaminate the oil.
Seal leakage gradually appears: the slight oil leakage at the shaft end seal develops into obvious oil droplets. After adding new oil, the oil level drops below the standard mark again in a short period of time, indicating that the sealing structure has been damaged and the lubricant continues to flow out.
4、 Signs of parameter deviation during operation
Abnormal fluctuation of motor current: In the absence of sudden external load changes, the motor's operating current shows irregular small jumps, and the transmission efficiency slowly decreases, which is an implicit signal of deteriorating tooth meshing accuracy and abnormal increase in transmission resistance.
Sudden change in operating status: Irregular impact noise occurs during the start stop phase, and there are small periodic fluctuations in the output speed. After eliminating the coupling fault, the early damage caused by internal backlash and shaft positioning failure of the gearbox can be locked.
