What are the disadvantages of the splash lubrication system for K87-NA25-5.5KW-4P reducer
The K87-NA25-5.5KW-4P reducer belongs to the medium power hard tooth surface reducer. Although the splash lubrication system it is compatible with has the characteristics of simple structure and low maintenance cost, combined with the working condition characteristics of this model with a transmission ratio of 25 and a power of 5.5 kW, it has the following obvious disadvantages:
1. The lubrication effect is significantly affected by speed fluctuations
The oil supply of splash lubrication completely depends on the ability of the gear to rotate and carry oil, and the core depends on the speed of the low-speed large gear. The transmission ratio of this model of reducer is 25, and the low-speed output shaft speed is relatively low. If the equipment is in a low-speed operation state with no load and low load for a long time, the oil carrying capacity of the large gear will be greatly reduced, which cannot provide sufficient oil for the gear meshing area and bearings, and can easily cause problems such as dry friction on the tooth surface and increased wear on the bearing raceway; If the speed is temporarily increased due to working conditions, it will also cause excessive oil mist in the gearbox due to excessive gear stirring force, increasing the risk of seal leakage.
2. The precision requirements for oil level control are strict, and the operational fault tolerance is low
The oil level in the oil tank of this type of reducer should be strictly controlled within the range of 1/3 to 1/2 of the tooth height of the low-speed large gear. Low oil level can directly lead to insufficient oil carrying and lubrication failure; If the oil level is too high, it will increase the oil stirring resistance of the gear operation, causing additional power loss, while rapidly increasing the oil temperature, accelerating the oxidation and deterioration of the lubricating oil, and shortening the oil change cycle. Especially after equipment installation and maintenance, oil level calibration requires the use of a dedicated oil level gauge for repeated measurement, which is cumbersome to operate. Improper manual control can easily lead to subsequent lubrication failures.
3. Poor adaptability to installation posture and working conditions
The splash lubrication system is designed to adapt to horizontal installation conditions by default. If the gearbox of this model needs to be installed in a tilted or vertical position due to on-site layout, the oil distribution in the oil pool will be severely uneven, and some gears will not be able to immerse in the oil, directly losing their oil carrying capacity and causing lubrication interruption. In addition, the system is not suitable for heavy load and impact load conditions. When the gearbox is subjected to loads beyond the design parameters, the oil film strength in the gear meshing area is insufficient, making it difficult to buffer the impact and reduce friction, and prone to faults such as tooth surface adhesion and pitting corrosion.
4. Poor lubrication uniformity, key parts are prone to oil shortage
Splash lubrication belongs to the "indiscriminate oil distribution" mode, which cannot accurately supply oil to key parts such as high-speed gear meshing areas and high-precision bearings with concentrated loads like forced lubrication systems. The high-speed gear of this type of reducer has high rotational speed and high frictional heat, which requires higher demand for lubricating oil and heat dissipation capacity. However, the splashing oil is difficult to be directed to this area, which can easily lead to insufficient local lubrication; Meanwhile, the lubrication of the bearing seat relies on the oil flowing back from the inner wall of the housing. If the design of the inner wall oil guide groove is unreasonable, it will lead to insufficient lubrication of the bearing and shorten its service life.
