The Design And Theory Research Of62-Inch Defibrator Of Spindle Hydrostatic Axial Support

With the rapid development of industries in Chinese Medium Density Fiberboard (MDF) fields, the traditional small production line matching36-inch,38-inch defibrator cannot meet the market demand of fiber, the large production line matching50-inch,54-inch difibrator has become mainstream of development in Chinese MDF fields.However, as the defibrator disc diameter increases, the axial force generated by the spindle also increases, the traditional thrust bearing can not stand such a large axial force, in addition,current defibrators have problems such as large power consumption, unstable state of fiber, disc damage rapidly.Defibrator spindle axial support performance directly affects running accuracy of the spindle, spindle poor running accuracy inevitably appear problems mentioned above, therefore, rationally designing the defibrator spindle axial support was of particular importance.By studying and comparing the existing domestic and foreign large difibrator’s spindle axial support structure,finding out advantages and disadvantages,combined with actual production, finally proposed application of hydrostatic combined bearing to stand the62-inch difibrator spindle axial force.Preliminary designing the structure of hydrostatic bearing with twisted plate restiactor as the62-inch defibrator spindle front bearing,solving the performance parameters of the designed bearing, working out the defibrator spindle radial,axial displacement and oli film stiffness, compared with the dynamic and static disc gap control accuracy requirements, verifying the reasonableness of designed bearings. Preliminary theoretically analyzing the hydrostatic support mechanism by applying the basic principles of hydraulic transmission, and preliminary studying the dynamic characteristics of the feedback throttling hydrostatic support by using the transfer function method,by using the "Rolls criterion" to make a dynamic stability judgment of the hydrostatic radial and thrust bearing in62-inch defibrator, finding out the dynamic factors influencing the stability of the hydrostatic combined bearing, thereby reasonable design parameters of these factors to ensure that the system work in a stable area.In addition, preliminary designing spindle,sealing equipment, disc gap adjusting equipment, base and so on, making62-inch defibrator hosts moving model by using three-dimensional simulation software, using finite element analysis software to make static analysis and modal analysis on the important parts(including spindle, hydrostatic combined bearing and so on), respectively getting the various parts of the stress nephogram and maximum deformation nephogram,verifying the design requirement of strength and stiffness, modal analysis results providing a reference to reduce noise and to avoid generating machine resonance phenomenon. The design and theory research of62-inch defibrator of spindle hydrostatic axial suppor provide a new method for the existing domestic large defibrator spindle axial support, also provide an effective technical support for future large-scale development of domestic defibrator.