Due to the harsh operating environment of the reducer, failures such as wear and leakage often occur. The most important ones are:
1. Wear of the bearing chamber of the reducer, including the wear of the housing bearing box, the inner bore bearing chamber of the box, and the gearbox bearing chamber;
2. The shaft diameter of the gear shaft of the reducer is worn, and the main wear parts are on the shaft head, keyway, etc.;
3. The bearing position of the drive shaft of the reducer is worn;
4. Leakage on the joint surface of the reducer.
For the wear problem, the traditional solution is to repair welding or brush plating, but both have certain drawbacks: the thermal stress generated by the high temperature of repair welding cannot be completely eliminated, which is easy to cause material damage, resulting in bending or breaking of parts; Brush plating is limited by the thickness of the coating, which is easy to peel off, and the above two methods use metal to repair the metal, which cannot change the "hard-to-hard" matching relationship, and will still cause re-wear under the combined effect of various forces.For some large bearing companies, it is impossible to solve on-site, and more rely on external repair.Contemporary western countries mostly use the repair method of polymer composite materials to solve the above problems, which has comprehensive properties such as super adhesion and excellent compressive strength.It is repaired by polymer materials, which can be disassembled and free of machining. It is not affected by the thermal stress of repair welding, and the repair thickness is not limited. At the same time, the metal material of the product does not have the concessional property, which can absorb the shock and vibration of the equipment and avoid re-wear. It is possible to greatly extend the service life of equipment components, save a lot of downtime for enterprises, and create huge economic value.
For the leakage problem, the traditional method needs to disassemble and open the reducer, then replace the sealing gasket or apply sealant, which is not only time-consuming and laborious, but also difficult to ensure the sealing effect, and leakage will occur again during operation.The polymer material can control leakage on site. The material has superior adhesion, oil resistance and 350% elongation, which overcomes the influence of the vibration of the reducer and solves the leakage problem of the reducer for the enterprise.
Reason analysis of oil leakage of reducer
1. Pressure difference between the inside and outside of the reducer: During the operation of the reducer, the friction and heat of the motion pair and the influence of the ambient temperature increase the temperature of the reducer. If there is no vent or clogged vent, the pressure inside the machine will gradually increase. The higher the internal temperature, the greater the pressure difference with the outside, and the lubricating oil will leak from the gap under the action of the pressure difference.
2. The structure design of the reducer is unreasonable
1) The inspection hole cover is too thin, and it is easy to deform after tightening the bolts, making the joint surface uneven and leaking oil from the contact gap;
2) During the manufacturing process of the reducer, the castings are not subjected to annealing or aging treatment, and the internal stress is not eliminated, and deformation will inevitably occur, resulting in gaps and leakage;
3) There is no oil return groove on the box body, and the lubricating oil accumulates in the shaft seal, end cover, joint surface, etc., and leaks from the gap under the action of the pressure difference;
4) The shaft seal structure design is unreasonable.Early reducers mostly used oil groove and felt ring type shaft seal structure, which caused the felt to be compressed and deformed during assembly, and the joint surface gap was sealed.If the contact between the journal and the seal is not ideal, the seal will fail in a short time due to the extremely poor compensation performance of the felt.Although there are oil return holes on the oil ditch, it is very easy to be blocked and the oil return effect is difficult to play.
3. Too much lubricating oil: During the operation of the reducer, the oil pool is greatly agitated, and the lubricating oil splashes everywhere in the machine. If the lubricating amount is too much, a large amount of lubricating oil will accumulate on the shaft seal, joint surface, etc. Cause a leak.
4. Improper maintenance process: During equipment maintenance, oil leakage will also occur due to incomplete removal of dirt on the joint surface, improper selection of sealant, reverse installation of seals, and failure to replace seals in time.
Countermeasures to control the oil leakage of the reducer
1. Improve the vent cap and inspection hole cover: the internal pressure of the reducer is greater than the external atmospheric pressure is one of the main reasons for oil leakage. If you try to balance the pressure inside and outside the machine, oil leakage can be prevented.Although the reducer has a vent cap, the vent hole is too small, which is easy to be blocked by coal dust and oil pollution, and the inspection hole cover must be opened every time when refueling. There are also leaks in places.To this end, an oil cup type air cap was made, and the original thin inspection hole cover was changed to 6 mm thick, and the oil cup air cap was welded on the cover plate. The diameter of the air hole was 6 mm, which was convenient for ventilation. The pressure is equalized, and the oil is added from the oil cup when refueling, so there is no need to open the inspection hole cover, which reduces the chance of oil leakage.
2. Smooth flow: To prevent the excess lubricating oil thrown on the bearing by the gear from accumulating at the shaft seal, the excess lubricating oil must flow back to the oil pool in a certain direction, that is, to achieve smooth flow.The specific method is to open an oil return groove in the center of the lower shell of the bearing seat, which is inclined to the inside of the machine, and also open a gap at the straight mouth of the end cover. Return to the oil tank.
3. Improve the shaft seal structure
1) Improvement of the shaft seal of the reducer whose output shaft is a half shaft: the output shaft of the reducer for most equipment such as belt conveyors, screw unloaders, and impeller coal feeders is a half shaft, which is more convenient to transform.Disassemble the reducer, remove the coupling, take out the shaft seal end cover of the reducer, machine a groove on the outside of the original end cover according to the size of the matching skeleton oil seal, and install the skeleton oil seal with the side with the spring facing inward.When reassembling, if the end cover is more than 35 mm away from the inner end face of the coupling, a spare oil seal can be installed on the shaft outside the end cover. Once the oil seal fails, the damaged oil seal can be taken out and the spare oil seal can be pushed into the end cover, thereby It saves time-consuming and laborious processes such as disassembling the reducer and disassembling the coupling.
2) Improvement of the shaft seal of the reducer whose output shaft is the whole shaft: the output shaft of the reducer with the whole shaft transmission has no coupling.In order to reduce the workload and simplify the installation procedure, a split end cover is designed, and an open oil seal is tried.The outer side of the split end cover is machined with grooves. When installing the oil seal, take out the spring first, cut the oil seal to form an opening, put the oil seal on the shaft from the opening, connect the opening with adhesive, and then install the opening upward. On the spring, push in the end cap.
4. Adopt new sealing material: For the leakage of the static sealing point of the reducer, a new polymer repair material can be used for blocking.If the oil leaks at the static sealing point during the operation of the reducer, the oil surface emergency repair agent of surface engineering technology can be used to block the oil surface emergency repair agent - polymer 25551 and 90T composite repair material, so as to achieve the purpose of eliminating oil leakage.
5. Conscientiously implement the maintenance process: when the reducer is overhauled, the process regulations must be carefully implemented. The oil seal should not be installed backwards, the lip should not be damaged, the outer edge should not be deformed, the spring should not fall off, the joint surface should be cleaned, the sealant should be applied evenly, and oil should be added. The amount should not exceed the scale of the oil dipstick.
6. Wipe: The static sealing points of the reducer can generally be prevented from leaking and leaking through treatment. However, due to the aging of the seals, poor quality, improper assembly, and high surface roughness of the shaft, the dynamic sealing points of the individual dynamic sealing points still remain. There is a small leakage. Due to the poor working environment, the coal dust sticks to the shaft and looks oily, so it is necessary to wipe the oil on the shaft after the equipment stops running.
The noise of the reducer is mainly due to the friction, vibration and collision of the transmission gear. How to effectively reduce and reduce the noise and make it more in line with the environmental protection requirements is also a key research topic at home and abroad.Reducing the gear transmission noise during the operation of the reducer has become an important research topic in the industry. Many scholars at home and abroad regard the change of gear tooth mesh stiffness in gear transmission as the main factor of gear dynamic load, vibration and noise.Use the method of modification to minimize the dynamic load and speed fluctuation to achieve the purpose of reducing noise.This method has proved to be a more effective method in practice.However, with this method, it is necessary to have reshaping equipment in the process, which is often impossible for the majority of medium and small factories to implement.
After years of research, it is proposed to optimize gear parameters, such as displacement coefficient, tooth height coefficient, pressure angle, and center distance, to minimize the impact velocity of the engagement, and the ratio of the impact velocity to the engagement velocity is at a certain value. The gear design method that reduces or avoids the impact of the meshing pitch circle can also significantly reduce the gear noise of the reducer.For reducer noise issues, there is also Miteray Super Sealant or Lubricant, an excellent gearbox additive that forms a film of inert material on the components, reducing friction, gear noise and leakage.