Common problems, solutions, and cause analysis of reducers

Date:2022-01-18 15:18:59

1) Reducer overheating and oil leakage
The reducer is experiencing overheating and oil leakage. To enhance efficiency, worm gear reducers typically utilize non-ferrous metals for the worm wheel and harder steel for the worm. Due to its sliding friction transmission, high heat is generated during operation, leading to differential thermal expansion between various components and seals of the reducer, resulting in gaps on the mating surfaces. Additionally, as the temperature rises, the oil becomes thinner, making it prone to leakage. There are four primary reasons for this: firstly, whether the material combination is reasonable; secondly, the surface quality of the meshing friction surfaces; thirdly, the selection of lubricating oil and whether the addition amount is correct; and fourthly, the assembly quality and usage environment.
Solution: Ensure assembly quality. To ensure assembly quality, the factory purchased and made some specialized tools. When disassembling and assembling components such as reducer worm gears, worms, bearings, and gears, direct hammering or the use of other tools should be avoided as much as possible. When replacing gears, worm gears, and worms, it is recommended to use original factory parts and replace them in pairs. When assembling the output shaft, attention should be paid to tolerance and fit. For D ≤ 50mm, H7/k6 is used, and for D > 50mm, H7/m6 is used. At the same time, anti-adhesive agents or red lead oil should be used to protect the hollow shaft, prevent wear and rust, and prevent dirt from accumulating on the mating surface, which would make it difficult to disassemble during maintenance.
2) Worm gear wear
The worm gear is worn. The worm gear is generally made of tin bronze, and the mating worm material is usually 45 steel quenched to HRC45-55, or 40C quenched to HRC50-55. After being ground by a worm grinding machine to a roughness of Ra0.8 fcm, the worm acts like a hardened "file" during the normal operation of the reducer, continuously filing and wearing down the worm gear. Generally speaking, this kind of wear is slow, and some reducers from a certain factory can be used for more than 10 years. If the wear rate is faster, it is necessary to consider whether the selection of the reducer is correct, whether it is operating at overload, and whether the material, assembly quality, or usage environment of the worm gear and worm are the reasons.
Solution: Selection of lubricating oil and additives. Generally, 220# gear oil is used for worm gear reducers. For some reducers with heavy loads, frequent starts, and poor operating environments, the factory also selects some lubricating oil additives. When the reducer stops running, the gear oil still adheres to the gear surface, forming a protective film to prevent metal-to-metal contact during heavy loads, low speeds, high torques, and starts. The additives also contain seal ring conditioners and anti-leakage agents, which keep the seal rings soft and elastic, effectively reducing lubricating oil leakage.
3) Wear of the transmission bevel gear
The transmission bevel gear is worn. This typically occurs on vertically installed reducers and is mainly related to the amount of lubricating oil added and the choice of lubricating oil. When installed vertically, it is easy to cause insufficient lubricating oil. When the reducer stops running, the transmission gear oil between the motor and the reducer is lost, and the gear does not receive the proper lubrication protection. During startup or operation, effective lubrication is not obtained, leading to mechanical wear and even damage.
Solution: Selection of the installation location for the reducer. When the location permits, vertical installation should be avoided as much as possible. When installed vertically, the amount of lubricating oil added needs to be much larger than that for horizontal installation, which can easily cause the reducer to heat up and leak oil. Some of the 40,000 bottles/hour pure draft beer production lines introduced by the factory were installed vertically. After a period of operation, the drive pinions suffered significant wear and even damage. After adjustments, the situation improved greatly.
4) Damage to the bearing (at the worm gear)
The worm gear bearing is damaged. When the reducer malfunctions, even if the reducer housing is well sealed, the factory often finds that the gear oil inside the reducer has been emulsified, and the bearing has rusted, corroded, and become damaged. This is due to the condensation of moisture generated when the gear oil changes from hot to cold during the operation and shutdown of the reducer; of course, it is also closely related to the quality of the bearing and the assembly process method.
Solution: Establish a corresponding lubrication maintenance system. The factory maintains the reducers according to the "five fixations" principle of lubrication work, ensuring that each reducer is regularly inspected by a responsible person. When phenomena such as a significant increase in oil temperature, a temperature rise exceeding 40°C or an oil temperature exceeding 80°C, a decline in oil quality, or the discovery of a large amount of copper powder in the oil, as well as abnormal noise, are observed during operation, the equipment should be immediately stopped for timely maintenance, troubleshooting, and lubricant replacement before use. When refueling, it is important to ensure that the oil quantity and installation position are consistent to ensure that the reducer is properly lubricated.
Analysis of common problems and causes of worm gear reducers:
The gear-worm gear reducer is a transmission mechanism characterized by its compact structure, large transmission ratio, and self-locking function under certain conditions. Additionally, it is easy to install and has a reasonable structure, making it increasingly widely used. It is a multistage reducer formed by adding a helical gear reducer to the input end of the worm gear reducer, which can achieve a very low output speed. Compared to single-stage worm gear reducers, it has higher efficiency, lower vibration, noise, and energy consumption.