Study On Vibration Characteristics Of ZNL-1 Type Pine Chipper

Pine wood nematode disease is a highly contagious and most devastating disease of pine trees.In order to prevent the further spread of pests,the diseased pine wood must be treated in time to destroy the growth environment of nematode.The eggs of the nematode could not survive in the winter if the diseased pine wood was broken into particles or wood chips with a thickness less than 10mm.However,due to the influence of road conditions in the forest region,the transportation of diseased wood is inconvenient.Therefore,it is necessary to develop a mechanical equipment that can slice diseased pine wood in situ.The existing wood chipping equipment is large in size,heavy in weight and difficult to move.Therefore,according to the characteristics of existing chip cutting equipment and the basic physical and mechanical characteristics of common diseased pine wood,this paper improved and designed a portable light disc type pine wood chipper suitable for the work in the forest region of China,which is used for in-situ treatment of diseased pine wood in the forest region.It is necessary to study the vibration characteristics of the main working parts and even the whole machine.This paper uses ANSYS Workbench to conduct modal analysis of the whole machine;The motion characteristics of the chipper under two typical working conditions are analyzed.The experimental study is conducted on the influence of cutting parameter on the vibration of the chipper,The conclusions are as follows:(1)The 3d model of the whole machine is established with Inventor,the modal analysis of the whole machine is conducted in ANSYS Workbench.The first six order modal analysis results of the whole machine are as follows:In the first and second order modes,the engine swings back and forth,left and right;in the third and fourth order modes,the cutting mechanism swings back and forth,right and left;in the fifth and sixth order,the engine and the cutting mechanism have torsional deformation respectively.(2)The vibration of the chipper mainly comes from the vibration of the cutting mechanism.When there is no load,the vibration of cutting mechanism is mainly caused by the unbalance of cutter head.When cutting pine wood,the vibration of cutting mechanism is caused by discontinuous cutting force.The vibration model of the cutter plate-spindle of the chipper under two typical working conditions was established,and its motion characteristic equation was obtained.The motion characteristic curve of the cutting parts under different factors was plotted by MATLAB.It is found that when the chipper is running without load,the vibration speed and acceleration increase with the increase of spindle speed.When cutting pine wood,the amplitude,vibration speed and acceleration of the cutting machine increase with the increase of cutting diameter and spindle speed.(3)According to the vibration test results of the sample machine,the vibration acceleration diagram and spectrum diagram of the chipper in no-load and under load.According to the figure,the vibration acceleration of the cutting mechanism in all directions is small under the condition of no load.With the increase of the spindle speed of the cutter head,the vibration acceleration of the cutting mechanism increases in all directions.The vibration acceleration of cutting mechanism increases greatly in all directions when it is under load.With the increase of spindle speed of cutter head,vibration acceleration of cutting mechanism increases in all directions.With the increase of wood diameter,the vibration acceleration of cutting mechanism increases in all directions.The experimental results agree with the theoretical analysis.