Study On Pressure Resistance And Starting Torque Of Magnetic Fluid Rotary Seal

Due to the limitation of power and torque of driving motor,some dynamic sealing occasions have clear requirements on starting torque requirements,such as airborne photoelectric pod seal and radar waveguide seal and so on.Compared with the traditional seal forms,the magnetic liquid seal not only has excellent sealing performance,but also has significant advantages in starting torque because the magnetic liquid seal is a non-contact seal,which can play a sealing role without relying on the contact between solids.However,in different environments,the starting torque of magnetic liquid seal fluctuates greatly,which cannot meet the dual requirements of pressure and torque for some extreme sealing occasions,thus limiting the application of magnetic liquid seal in such sealing occasions.This subject takes temperature as the entry point,has carried on the theory and the experiment research on the magnetic liquid sealing pressure resistance ability and the starting torque,obtained the temperature and the magnetic liquid sealing pressure resistance ability and the starting torque relations.Meanwhile,the pressure transfer mechanism of magnetic liquid seal and the movement state of magnetic liquid are analyzed,and based on this,the influence of pressure on the starting torque of magnetic liquid seal is explored.The following research has been completed around this goal:(1)The test bench was designed and built to directly observe the magnetic liquid in the seal gap,the clarity of the magnetic fluid sealing pressure transmission is a step by step process.At the same time,the movement state and boundary shape of magnetic liquid in the sealing gap under different pressure were observed,which laid a foundation for the follow-up research on the influence of pressure on starting torque.(2)In order to carry out the test of withstand pressure and starting torque,a magnetic liquid rotary seal device was designed.Combined with the finite element software,the seal gap,polar tooth profile and permanent magnet thickness were simulated,and the relevant parameters were finally determined.The whole sealing structure is simulated by magnetic field,and its rationality is confirmed,and the theoretical pressure limit of the seal structure is calculated.(3)Through the pressure resistance test,it can be found that the pressure resistance ability of magnetic liquid seal has a linear positive correlation with the amount of magnetic liquid injection in a certain range.The larger the seal gap,the smaller the pressure tolerance,and the smaller the gap,the greater the impact of its change on the pressure tolerance.By changing the experimental temperature,it can be concluded that the pressure resistance capacity of magnetic liquid seal is greatly affected by the temperature.The lower the temperature is,the greater the maximum pressure resistance value is.(4)Through the starting torque experiment,it can be known that with the increasing pressure,the starting torque will gradually decrease,and the overall trend is linear.The starting torque is greatly affected by temperature,and the lower the temperature is,the greater the starting torque will be.Moreover,the influence of the amount of magnetic fluid on the starting torque is particularly prominent at low temperature,while it significantly decreases at high temperature.(5)The relationship between the pressure-resisting ability and the starting torque is fitted out,and the changing trend of the starting torque with the pressure-resisting ability is analyzed,which provides a reference for the balance between the pressure bearing capacity and the torque.Figure 64,table 14,58 references.