【作者】 霍光青；

【导师】 王乃康； 李文彬；

【作者基本信息】 北京林业大学 ， 机械设计及理论， 2008， 博士

【摘要】 立木整枝是优质工业用材林定向抚育的重要环节。传统的整枝方法效率低、易引起工人的疲劳和作业事故、作业高度也受到限制,因此,自动、半自动化的立木整枝机是实现高效、高质量和安全可靠整枝的有效途径。本文是在分析树木对整枝作业要求的情况下,进行了以下研究;1、通过对常见树木的调查、分析和统计,研究树干上树枝的形态,如树枝的直径、角度等,确定整枝机械的最佳参数。如整枝机可以工作的树干直径,可以切削的树枝直径与角度。研究表明立木整枝机可以整枝的立木树干直径应在8-22cm之间,树枝的直径在0-6cm之间,树枝与树干的角度应在30度以上。2、分析整枝机的工作方式,研究立木整枝机最佳的工作方式与切削机构。研究表明;遥控机械式半自动整枝机是比较适合的一种整枝机械,螺旋式上升、锯切、下降是一种较好的工作方式。链式锯切机构是整枝机上较合理的切削机构。整枝机的锯切机构应当设计相应的避让机构,避开不利的切削状态。3、研究整枝机支架类零件的设计,利用三维曲面、曲线设计方法、设计思想,研究该类零件的设计。利用投影曲线(如曲线的两个投影)方法建立空间的曲线,然后再建立空间物体的三维模型是空间支架类零件较好的三维设计方法。4、研究树木的树皮与轮胎的相互作用,测定轮胎与树木间的滚动阻力系数,计算整枝机在树木上运动所需要的功率,为发动机的选择提供必要的基础数据。实验中采用了传感器技术,测定测试系统中受到的力,最后计算出滚动阻力系数及在一定运动速度下所消耗的功率。5、研究整枝机上升、下降、锯切需要的运动,设计合理的传动、操作机构。试验和研究表明矩形截面弹簧是小型动力机械中一种较好的传动元件,通过合理的组合与控制,可以利用矩型截面弹簧实现变速与传动扭矩的目的。6、研究树枝的形态与避让机构的结构、运动关系,运用三维动力学分析的方法,分析了碰撞式机械避让机构的各零件在工作中的运动关系和参数,提出避让机构中零件最佳的结构和参数以及结构优化的方法。更多还原

【Abstract】 Pruning is one of the most important and necessary step of cultivating plantation forest.The traditional pruning machine has low working efficiency,high casualty,limited prunning height and is difficult to meet the need of fostering the large area of commercial plantation in China.So the key method is to develop an automatic pruning technology,which should be safe,high quality and efficient.Based on analying and studying of the request of tree to the pruning processes,this paper carried on a research at following several problom;1.By the inquisition,analysis and statistics of familiar trees,study the shape of tree branch,make sure the best parameter of the pruning machine,such as the diameter,angle...etc,of the tree branch that it can cut.The research shows;diameter of trunk that tree’s pruning machine can cut is 8-22cm,the diameter of the tree branch is between the 0-6 cm,the angle of the tree branch and tree trunk should be in more than 30 degrees.2.Analyze the work method of the pruning machine,study best work method and cutting mechanism of pruning machine.Study shows;the pruning machine with remote controling, semiautomatic and rose,fall and cut with helical is a better work method.The chain type’s sawing mechanism is most reasonable cutting mechanism.Avoid reasonless cut mechanism shoud be designed, evade reasonless cutting status.3.It studies design of pruning machine’s backstop; make use of 3D surface and curve design method and thought to research design thought of the kind of parts.Make use of projection of curve (such as two projections of the curve)to establish space curve,and then make the digital model of space subject space is better 3D design method of the kind of parts.4.It studies the bark of the tree and the interaction of the tire of pruning machine,measures roll friction coefficient of tire and the tree roll over and calculates requisite power when pruning machine rose on tree,provides important basis for the choice of power.The sensor technique is adopted in experimentation,the forces of test system is measured,then calculate roll friction coefficient and requisite power at specifically speed.5.It studes motion of pruing machine when it rise,descend and saw,then design reasonable mechanism of transmission and operation.Experiment and reserach shows spring with rectangle’s section is a kind of better parts in the transmission of small machine; it can be extensively used for delivering to torque and motion.The purpose of change transmission velocity can be achieved by reasonable design and combine.6.It studies relation between the status of the branchof tree and structure of avoid mechanism and motion,bring forward best structure and parameters in avoid mechanism.In a word,the textual research is some design methods of the quest in the pruning machine design. The result and method of this research provid a new method and thought for design and research of pruning machine.更多还原