Preheating operation has a significant positive impact on the service life of the NGW83-1-180 planetary reducer. Scientific and standardized preheating can significantly reduce component damage under low-temperature conditions and extend the service life of the entire machine. On the contrary, non-standard preheating or starting without preheating will increase wear, induce embrittlement failure, and shorten the life of the equipment. Specifically, it can be analyzed from the following 4 core dimensions:
NGW83-1-180 is a medium- and heavy-duty planetary reducer. The core gear is made of alloy steel. In low temperature environments (especially below - 10°C), the material toughness will significantly decrease and the elastic modulus will increase. At this time, it will be started directly at full load. The meshing of the planetary gear with the sun gear and the internal ring gear will produce impact stress 2-3 times the rated load. Standard preheating can raise the temperature of the box and core components to 10-20°C, restore the impact toughness of the material, and at the same time allow the lubricating oil to fully flow and form an effective oil film to buffer the impact force during the meshing process and avoid initial damage such as micropitting and chipping on the tooth surface. If these initial damages are not avoided in time, they will quickly expand into cracks in subsequent operations, eventually leading to brittle fracture of the gear. Scientific preheating can reduce the incidence of such failures by more than 80% and directly extend the design life of the gear by 30%-50%.
2. Optimize the lubrication state to avoid dry friction and boundary friction and wear
In a low-temperature environment, the viscosity of the reducer's lubricating oil will rise sharply and even partially solidify. When starting without preheating, it is difficult to form a complete oil film on the gear meshing surface and the bearing raceway, and dry friction or boundary friction will easily occur, causing adhesive wear and abrasive wear on the metal surface. The preheating operation can increase the oil temperature to a reasonable range (recommended 15-25°C), restore good fluidity of the lubricating oil, ensure that the lubrication points are fully lubricated, form an oil film with a uniform thickness, effectively isolate the metal friction surface, and reduce the wear rate. For NGW83-1-180 heavy-duty bearings, preheating can avoid rolling element slippage during low-temperature startup, reduce fatigue damage to the inner and outer raceways of the bearing, and extend the service life of the bearing. According to industry statistics, standardized preheating can extend the service life of the bearing by 40%-60% and reduce the number of machine shutdowns for maintenance due to bearing failure.
3. Alleviate low-temperature stress concentration and prevent deformation and cracking of boxes and structural parts.
The box body of NGW83-1-180 is mostly made of ductile iron or cast steel. The shrinkage rate of the material will increase at low temperatures. If it is started directly, the torque transmitted by the motor will cause the box body, planet carrier and other structural parts to bear the superposition of uneven thermal stress and mechanical stress. It is easy to produce micro-cracks in stress-concentrated parts (such as the box bearing seat and planet carrier welds). The preheating operation can evenly increase the temperature of the box, reduce the temperature difference between the inside and outside of the components, and avoid structural stress caused by uneven thermal expansion and contraction. At the same time, the temperature of the fasteners (bolts, nuts) can be increased simultaneously, alleviating the attenuation of bolt pretightening force at low temperatures, and preventing increased vibration caused by loosening of the connection parts. In the long run, standardized preheating can effectively avoid structural failures such as box cracks and planetary carrier deformation, allowing the entire machine to fully utilize its designed service life. Especially in deep low-temperature environments below -20°C, preheating plays a more prominent role in protecting the life of structural parts.
4. Avoid the risk of reverse damage caused by improper preheating
It should be noted that irregular preheating operations will have a negative impact on the life of the reducer and will in turn aggravate the damage. For example, if the preheating temperature is too high (exceeding 40°C), the viscosity of the lubricating oil will be excessively reduced, the load-bearing capacity of the oil film will be reduced, and the oil film will easily rupture during gear meshing; if the preheating time is too long (more than 2 hours) without cranking, the local oil temperature will be too high, causing oxidation and deterioration of the lubricating oil, and sludge will be generated to block the oil circuit; no-load cranking will be performed during preheating, and the lubricating oil will not be circulated to all lubrication points, which will still lead to insufficient local lubrication. In addition, if the 'low-speed gradual loading' principle is not followed after preheating and the load is instantaneously loaded to the rated load, a large impact load will also be generated and damage the components. Therefore, only by following the scientific preheating process of 'accurate temperature control, reasonable time, cooperation with turning, and graded loading' can the positive protective effect of preheating on lifespan be maximized.
