Tel:400-021-2232
Phone:+86-15900888686
Email:1002145733@qq.com
Address:Building 1, No. 377, Nanqiao Road, Nanqiao Town, Fengxian District, Shanghai
Failure cause and improvement scheme of fag imported bearing seat seal
2021-10-16Fag imported bearing seat sealing improvement scheme "multi-stage pressure relief sealing technology" experimental bearing seat sealing ring, which can reduce lubricating oil leakage by reducing the pressure difference at both ends of the seal without shaft extraction and other large-scale disassembly working environment, and return the residual leaked lubricating oil to the oil tank to achieve the purpose of shaft seal leakage prevention. Specific main technical indicators: the experimental bearing seat sealing ring of "multi-stage pressure relief sealing technology" can be replaced without disassembly in the original position of the main shaft, and there is no abnormal lubricating oil leakage accident within the two-year cycle of normal operation. The specific research contents are as follows.
Study on selection of sealing materials and optimization of sealing ring performance
In view of the existing shortcomings of ship working conditions, external environment and zero diameter sealing rubber ring, a new sealing rubber ring more suitable for ship stern shaft intermediate bearing seat is selected or developed. The selection of sealing materials mainly adopts the method of experimental research. Several groups of materials with good elasticity, aging resistance and wear resistance are selected to make a sealing apron with wear and self compensation function and reasonable contact surface. The wear resistance and sealing performance tests are carried out, and the sealing aprons of the middle FAG imported bearing block of ship stern shaft are selected. On this basis, it can be improved as needed to meet the requirements. This is mainly because this technology is a special technology and requires a long time of special research. The research on the structure, stress and deformation of the seal mainly adopts the finite element analysis method to provide the basis for the structural design. Design analysis and experimental methods are used to reduce the pressure on the friction surface and reduce friction and wear. The anti-wear performance and service life of seals are also mainly studied by experimental research methods. Through the experimental comparison of various sealing materials, the appropriate bearing seat sealing rubber ring is selected by step-by-step optimization method. The selection of sealing sequence, material and additional equipment depends on different parameters. The pressure and temperature of the medium to be sealed and the diameter and revolution of the shaft to be sealed are important parameters to consider the functional safety in the design. For evaluation, the pressure of the product and the roughness of the sealing surface are often taken as the evaluation values. Other edge conditions include the installation environment, product characteristics such as chemical attack, caking tendency and solid parts. This needle plays a fundamental role in sealing design for products or slurries with high solid content.
Development of fag imported bearing seat sealing structure
The sealing effect of single-stage seal is not ideal, and the lubricating oil leakage of bearing seat is serious. On the premise of meeting the structural dimensions of the shaft system, it is proposed to newly develop the sealing system of the intermediate bearing seat of the stern shaft. The new system adopts the structure of two-stage sealing and oil retaining ring. The new oil retaining ring can partially prevent the leakage of lubricating oil in the oil tank along the shaft surface. If the first stage seal leaks, the lubricating oil will enter the cavity between the two seals. Due to the oil drain circuit at the bottom of the cavity, the leaked lubricating oil will not form pressure in the cavity, and the second stage seal will basically not leak. It can be seen that the multi-stage pressure relief seal reduces the damage degree of vulnerable parts and prolongs the service life. Its seal adopts one positive pressure rubber ring and one negative pressure rubber ring. When the medium is sealed, the first level rubber seal seals the medium. Even if a little medium passes through the first level rubber ring, the second level rubber ring plays a role, and the external pressure is greater than the pressure in the shaft seal. Under the action of the internal and external pressure difference, the two-level sealing rings play a role at the same time, firmly pressing the rubber ring on the main shaft to play a sealing effect; When the fag inlet bearing is running, the pressure in the shaft seal is greater than the atmospheric pressure, and the primary seal ring plays a role. The leakage pressure generated by the lubricating oil entering the seal ring oil seal 1 is converted into kinetic energy to work on the rubber ring, and the seal ring oil seal 2 is firmly pressed on the main shaft, which plays a sealing effect. Therefore, the multi-stage seal is realized through the secondary sealing element by using the effect of liquid pressure difference, rather than the sealing requirements by packing extrusion or spring. According to the pressure and structural requirements, rubber rings can also be added to realize multi-stage seal cooperation, so as to greatly prolong the service life of the seal, avoid frequent replacement of the seal and play a better sealing effect.