Speed reducers are generally used in low-speed, high-torque transmission equipment. They reduce the speed of power from electric motors , internal combustion engines, or other high-speed operations by having a small gear on the input shaft mesh with a large gear on the output shaft. Speed reducers are relatively sophisticated machines used to reduce speed and increase torque.
1. The effect of gearbox lubricating oil
The primary function of lubricating oil in a speed reducer during gear transmission is to reduce friction and wear between different bearings, such as ball bearings, roller bearings, rolling bearings, and needle roller bearings, and between mechanical transmission components, thereby reducing friction resistance between component contact surfaces.
Lubricating oil reduces energy consumption, improves machine transmission efficiency, extends the service life of various components, and ensures normal equipment operation. At the same time, lubricating oil in the reducer also plays a role in vibration absorption, cooling, temperature reduction, heat dissipation, rust prevention, and noise reduction.
2. The primary form of gearbox malfunction due to lubricating oil
(1) The internal structure of the reducer is not designed properly: In the reducer structure, the cover plate above the inspection hole is designed to be too thin. After the screws are tightened, the part is easily deformed, resulting in contact gaps and oil leakage. The castings were not annealed during the manufacturing process.
Oil leakage can be caused by deformation and gaps in the gearbox housing. It may also be due to the lack of a return oil groove on the housing. When too much lubricating oil accumulates at the end cover and structural joint of the gearbox housing, the pressure difference causes the lubricating oil to leak out from the joint gap.
(2) Oil leakage from the gearbox causes environmental pollution: In the reducer, oil leakage from the gearbox may be caused by factors such as damaged oil seals, broken gaskets, loose oil plugs, or damaged oil level indicators. It may also be caused by excessive oil, excessively high oil level, or repeated cold starts, which may cause the lubricating oil to foam.
The phenomenon caused a large amount of oil to leak from the vent plug, resulting in severe environmental pollution.
(3) Overheating of oil causing equipment damage: During the operation of the reducer, due to insufficient lubricating oil or overload operation of the equipment, the temperature of the lubricating oil inside the reducer rises rapidly, causing partial damage to related components inside the reducer. Some equipment
Because internal stress is not eliminated, large deformation occurs upon heating, leading to a decrease in the precision of the speed reducer. Some components also experience a decrease in material strength at high temperatures, causing damage. Furthermore, some speed reducers that are sluggish in operation and suffer severe power loss may malfunction if foreign objects intrude during operation.
The transmission components may become stuck, resulting in uneven operation or abnormal vibration.
(4) Vibration and noise cause environmental pollution: After the reducer starts, the machine will vibrate significantly due to wear of gears and bearings or improper installation of the transmission device. Damaged bearings, worn gears, damaged gears, or foreign objects stuck in the gears will also cause the machine to emit noise.
Loud and prolonged harsh noises. These problems can all constitute serious noise pollution.
(5) Poor gear lubrication leads to tooth surface wear: Due to the harsh operating environment of the reducer, the lubricating oil film is not easily formed and stable between the meshing surfaces, resulting in pitting or friction wear on the gear surface, bearing housing, and gear shaft diameter surface.
Such phenomena lead to severe wear on the surface of the gears.
3. Causes of gearbox malfunctions due to lubricating oil
(1) Improper selection of lubricating oil: Different parts of the reducer have different requirements for the type, viscosity, and other properties of lubricating oil. Proper selection can reduce the frictional resistance between the contact surfaces inside the lubricating oil, thus reducing wear on the gear surface and transmission noise.
Vibration will also decrease. However, improper lubrication will greatly reduce the lubrication effect, easily cause the hydrodynamic oil film to break, and lead to pressure concentration on the contact surfaces of gears and other components, severely damaging the gear surfaces and even the equipment.
(2) Improper lubricating oil quantity: During high-speed operation of the reducer, the oil sump is violently agitated, and the lubricating oil splashes everywhere inside the reducer. If there is too much lubricating oil, it will cause oil leakage due to excessive accumulation at shaft seals, end covers, mating surfaces, etc., increasing the risk of oil leakage.
The increased operating resistance of rotating parts such as bearings and gears leads to increased power consumption and reduced heat dissipation space, resulting in higher oil temperature, decreased viscosity, and a thinner oil film. This disrupts the normal lubrication of the friction surfaces, causing severe wear on the equipment.
If the amount of lubricating oil is too low, the gears, bearings, and mating surfaces of the reducer will not receive enough lubricating oil to form an oil film, resulting in dry friction and severe wear of the equipment.
(3) Intrusion of contaminants such as air, mechanical impurities, and free water into the lubricating oil: During the operation of the reducer, the lubricating oil inside the machine is easily affected by contaminants such as mechanical impurities, water, and air. For example, free water can cause the lubricating oil to produce acidic substances, which can corrode metal.
As a component, it exacerbates wear. Air mixed in with the oil can cause the oil to oxidize and deteriorate, and even cause oxidation and corrosion of metal parts. Impurities reduce the cleanliness of the lubricating oil, deteriorate its quality, and decrease its viscosity grade, causing the speed control system to jam or malfunction, and even damage the equipment.
4. Preventive measures
(1) Selection of lubricating oil: Based on the different operating environment, load size, motion characteristics, and friction modes of the reducer, the appropriate type of lubricating oil should be selected. For example, gear oil with low viscosity and good fluidity should be selected for high-speed gears, while gear oil with low viscosity and good fluidity should be selected for low-speed gears.
For moving gears, choose lubricating oil with good anti-wear properties; for gears operating at low temperatures, choose low-pour-point gear oil.
(2) Use of lubricating oil: To ensure the normal operation of the reducer, it is necessary to use lubricating oil correctly. ① Ensure the oil filler is clean and strictly prevent impurities and other contaminants from entering the oil tank to prevent water leakage, oil leakage, and oil mixing. ② Adding lubricating oil
The amount of lubricating oil should be appropriate, and the oiling operation should be carried out strictly according to the instructions in the relevant manual. Furthermore, the lubricating oil in the reducer should be changed regularly. ③ The lubricating oil should be operated under stable and suitable environmental conditions as much as possible. The oil temperature during operation should generally be ≤80℃, and the risk of oil leakage should be minimized.
Minimal environmental impact on lubricating oils.
In addition, selecting appropriate lubricating oil based on different uses and operating conditions of different types of reducers can not only ensure the stable operation of the lubrication system, but also reduce lubrication costs.
(3) Preliminary maintenance and fault diagnosis: Strengthen theoretical learning on gearbox lubrication oil maintenance and fault diagnosis, grasp the working principle of the gearbox, and combine theory with practice; regularly check the gearbox lubrication oil, and immediately find out the cause of any abnormality.
Early diagnosis and treatment of problems; regular cleaning of components to ensure cleanliness of working parts; strengthening maintenance of each component to reduce wear caused by contamination and extend the service life of the reducer.
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