| Highway plant hedge play an important role in protecting ecological environment and driving safety and reducing traffic accidents.At the same time,Pruning and maintenance highway green fences have strict standard,in general the height of green fences should be held in height between 1.2 to 1.5 meter.With the constant increase of the highway mileage and there is great difference between the planted time and varieties of green fences result in the maintenance is difficult.Artificial pruning is the main method for highway plant hedge in china at present.In recent years,although there are some pruning machines is developed by Some Locality,it is low to machineries utilization efficiency and not very adaptable and bad at service property,cannot meet the basically demand for the requirement of pruning highway green fences.Therefore,nowadays the highway green fences trimmed by pruning mechanization in our country is quite low,it will seriously restrict the national highway development with speedily and high standard.Based on the consulted a lot of home and abroad documents of other people,this paper analyzes on the advantages and disadvantages of the pruning machine of the current for plant hedge.Renewal designing and improvement of our team's experiment bench based on lots of investigations on advanced punning machines at present in China.This paper mainly Study and design on the tool holder which is an important composition of the pruning machine by the method of theoretical analysis and experimental study with our new team's experiment bench.The main research work of this paper was illustrated as follows:(1)On the basis of research and theoretical analysis and combined with the method of experimental study,the circular saw is finally chose as the tool of this study which will aid in the design of tool holder.Tree main factors of influencing clip effect are analyzed such as branch diameter and traveling speed and cutter-head rotation speed with the help of three factors quadratic regression rotational combination design method.And reasonable choice of the cutter-head rotation speed under the preset traveling speed to different diameter.Secondly, vibration condition for the circular saw was studied.A study on the relationship between critical speed and cutting speed with the method of modal analysis.The range of the critical Speed of the circular saw in three clamp diameter is given.The reasonable of the circular saw rotation speed under current clamp diameter is verified.(2)This paper analyses the cause that the tool post of the pruning machine cannot satisfy the needs nowadays and the required functions of the tool post when during cutting process.Aim at such problems,base on the characteristics and criteria of.highway-plant hedge.in.china,.using the basic principle and methods of mechanical design combined with the Pro/e Software,the tool post with the functions of "Split waves",has been designed.Static analysis on tool holder,it verified that its strength and stiffness could meet the demands of practical work need.(3)This paper analyses the force situation of the circular saw during the cutting process,and the force has been measured by the experiments that designed based on the laboratory equipment.Base on the measurement results can obtained:? Cutting the same class of diameter under the different regions of the circular saw which are divided by fixed knife,the maximum value of Fx and Fy kept almost in the same value.? Both the cutting force of FX and Fy increase with the increasing of traveling speed.? Cutting branches in a transverse line,the relation between each other is basically mutually independent,the cutting process of multiple branch just acts as repetitive process of single branch.Cutting branches in a vertical line,the feed-direction force Fx increase faster than the vertical feed-direction force Fy,but when cut many branches that come alongside the cutting force not a increase times embodiment.The force of FY increased rapidly is slightly less than increased with times,Fy at a rate of slow growth.(4)Identification on the fatigue failure.A coupling analysis was used for the circular saw by ANSYS and the fatigue calculation of this Model was analyzed with the fatigue module of ANSYS.According to the result that in the current experiment and under working condition of the circular saw rotating at the speed of 3000r/min and tracking speed is kept at 9.3km/h fatigue failures occurred when cutting the branches of ficus which diameter were between 30mm-40mm,the coefficient of fatigue filature is 6.207×10-7.Tipping and fracture phenomenon of circular saw occurred at the cumulative value of the fatigue filature is equal to 1 when the number of branches reaches to 1.611084×106 cut by Individual Cutter head.It is normal wear of the circular saw when use them to cut the first and third classes of branches under tracking speed is kept at 9.3km/h and reasonable matching of cutter head rotation speed.Then the circular saw will not occur fatigue failure. |
PDF Full Text Request