Study On The Dynamic Stability Of Rotor System Of Wood-working Circular Saw

Through analyzing the structure of wood-working circular saw machine,the features of its bearing axletree and the working process and taking the homemade MJ-90 panel saw rotor system(saw, clamping device,step pulley,saw spindle,and the bearing system)as the research object,this paper, for the first time,take the wood-working circular saw as the rotor system and use XLROTOR,which is a business software package of big rotor system dynamics developed Rotating Machinery Analysis Ltd, to set up a dynamics model of wood-working circular saw rotor system.This model includes not only the effects on the dynamic capability of wood-working circular saw machine by the structure and installing position of each rotary components(such as saw,flange, fastening nut,principle axis,pulley,and so on)of wood-working circular saw machine,but also the effects by the structural parameter,working parameter,and the installing position of the bearing axletree. For the aforesaid model of which the wood-working circular saw machine could include the above-mentioned factors,we haven't seen it in any relevant published works so far.Based on it and with a number of analysis and calculations,this paper makes a relative detailed research and makes the main conclusions as following;1.The gyroscopic effect exists in the rotor system of wood-working circular saw machine,and seriously influences the critical speed of the rotor system.And there also is a close relation between the gyroscopic effect of the main parts of rotor system and the critical speed of the rotor system.For example,the diameter size of circular saw has a greater effect on the critical speed.When design the wood-working circular saw machine,it is especially important to considerate the effect of the dynamic capability of the wood-working circular saw machine by the bigger-size saw parts..2.Through a number of calculations,this paper comes into a result that the rotor system can reach the top-degree critical speed when the ratio of the cantilever of wood-working circular saw machine and the bearing span is between 0.349 and 0.52.Therefore,to improve the critical speed of rotor system, when we design the bearing span and the cantilever length we should conform to the best dynamic relation between them.3.This paper sets up a curve for the relation between the imbalance size of the main parts of rotor system and the imbalance response of the circular saw center.The conclusions for the research on the imbalance influence of the imbalance amounts of rotor system main parts to the imbalance response of the circular saw center are;among the imbalance response of the circular saw center by respective imbalance amounts and their integrated imbalance amounts(symmetrical phase)of external flange, circular saw,step pulley,and saw axis,the one of extemal flange and circular saw is the main factor.In addition,we should control the imbalance amounts caused by the difference of materials which is also one of the main factors for the loss of saw kerfs.4.According to the phenomenon of the saw axis vortex motion,this paper establishes a calculation formula for the loss of saw kerf(ΔB)of cantilever wood-working circular saw machine to provide a reference for design;5.According to the calculation result of the imbalance response amplitude by XLROTOR,this paper analyzes and calculates the loss of saw kerf caused by the imbalanced amounts of main parts and makes this conclusion;To reduce the loss of saw kerf,it is more efficient to generally control the imbalance amounts cause by the different materials of main parts than to improve their tolerance.