Research On The Split-type Design Of Magnetic Fluid Seal With Large Axial Diameter

Shield machine is an advanced construction equipment which is currently used in tunneling of subways,railways,and highways,the sealing performance of key components such as main drive bearings will directly affect the normal work of the shield machine.When the traditional magnetic fluid seal is applied to large equipment,it is difficult to process,inconvenient to assemble and disassemble,and easy to generate stress concentration.In the complex working environment of shield machine,non-magnetic particles such as external sediment will enter into the shield machine,which will result in the damage of the main drive bearing and the failure of tunneling.This article intends to solve the problems of difficulty in processing,inconvenience in assembly and disassembly,and easy to generating stress concentration by designing a split-type magnetic fluid seal structure,block non-magnetic particles such as sediment,extend the life of magnetic fluid seal,and improve the seal stability.It is of great significance to solve engineering application problems such as the sealing of the main drive bearing of the shield machine.Focusing on these two problems,this article completes the following research:?1?The design scheme of the split-type magnetic fluid seal is proposed to solve the problems of the traditional magnetic fluid seal that is difficult to process,inconvenient to assembling and disassembling,and easy to generate stress concentration when it is applied to large-scale equipment.?2?Two qualitative and quantitative experimental schemes to study the rejection of magnetic fluids are proposed.Qualitative experiments were completed with Si O₂ as the main component of the rock,and the first-order buoyancy principle of the magnetic fluid is verified;a quantitative rejection experimental device is designed,the designing of quantitative experimental scheme to study the influencing factors of first-order buoyancy is completed.It is proved the problem that the magnetic fluid has rejection property,and the sealing device can block non-magnetic particles such as sediment.?3?Combining with the finite element software,the magnetic field simulation of different pole shoe thickness,sealing gap,pole shoe spacing,and pole shoe height are carried out,the relevant parameters of the pole shoe design are determined.The structural design of the main components of the split-type magnetic fluid seal is completed,and the assembly drawing of the seal structure is finally completed.?4?The static magnetic field simulation of the sealing structure is carried out by using ANSYS finite element simulation software,and the magnetic induction intensity distribution diagram of the sealing gap under the pole shoe is obtained.Combining with the formula of sealing pressure resistance,the theoretical pressure resistance value of the sealing structure is calculated,which indicates that the sealing structure has a good sealing pressure resistance capacity and further proves the feasibility of the sealing design scheme.