变导程螺旋副传动机理分析与相关技术研究

发布时间：2018-05-28 20:53

本文选题：变导程 + 螺旋传动　；参考：《南京理工大学》2015年博士论文

【摘要】：随着机械制造行业的快速发展,变导程螺旋传动作为新兴的传动方式被提出。实现变导程的机构有多种形式,如圆柱凸轮,变导程蜗轮蜗杆等。对于圆柱凸轮,传动件在凸轮槽内做圆周循环运动,而对于变导程蜗轮蜗杆,蜗杆只能相对于蜗轮短距离的位移变化。本文对变导程传动机构进行结构分析,提出变导程螺旋传动机构模型。利用TRIZ技术创新理论中的分割理论,将滚珠丝杆和圆柱槽凸轮的旋向与导程属性提炼出来并加以组合,得到变导程螺旋传动机构。经过机构创新,变导程螺旋传动机构比传统螺旋传动机构具有自适应性、自锁性、可变导程性、流体动力润滑等新特性。这些功能在实际应用场合具有重要意义。考虑参数和特性两方面因素,建立螺旋传动机构的理想度模型,并计算了滑动丝杆、滚动丝杆、变导程丝杆的理想度,量化结构创新的比较方法。建立了变导程变半径丝杆螺旋槽曲面和通用滚子轮廓曲面的数学模型。分析其啮合特性,建立间隙函数。在半径不变条件下,对圆柱面上的变导程螺旋线的几何特征进行了研究,得到了曲率和挠率的表达式。利用圆弧过渡和多项式过渡方式,对圆柱面上螺旋线进行优化设计。按照极值条件建立过渡曲线泛函,通过变分原理进行求解。针对变导程螺旋传动机构运动学进行建模,利用坐标变换理论,螺旋理论计算了滚子和螺旋槽传动过程中二者的相对滑动速度以及实现纯滚动的条件。通过多目标优化和模糊理论对广义滚子运动参数进行了优化设计,与优化前传动特性进行了比较,并验证结果。根据Hertz弹性接触理论,提出变导程螺旋副滚动接触简化模型,计算三维滚动接触的应力分布。考虑实际情况和加工条件影响,给出了滚子与螺旋槽之间点接触和线接触的几何条件,并得到了点接触的结论。根据最小油膜厚度与粗糙度的关系,以及接触区域椭圆率,综合判断各接触点处的润滑状态。通过Maple数学软件对接触过程中最小膜厚进行了仿真,得到最小膜厚在不同导程变化下,随滚子沿丝杆轴线位移的变化规律。研究了变导程螺旋副的摩擦磨损机理,分别对滚子和螺旋槽接触的具体工况进行分析,采用雨流计数法进行载荷谱的编制。然后利用强大的]HyperMesh前处理软件和FE-Fatigue疲劳寿命分析软件联合对变导程螺旋副疲劳寿命进行分析。最后研究了各种变导程函数对螺旋副疲劳寿命的影响。
[Abstract]:With the rapid development of machinery manufacturing industry, variable lead spiral drive is proposed as a new type of transmission. There are many kinds of mechanisms to realize variable lead, such as cylindrical cam, worm gear with variable lead and so on. For cylindrical cam, the transmission moves around the cam groove, but for the variable lead worm gear worm, the worm can only change relative to the short distance displacement of the worm gear. In this paper, the structure of variable lead drive mechanism is analyzed, and the model of variable lead spiral transmission mechanism is proposed. By using the segmentation theory of TRIZ technology innovation theory, the rotation and lead properties of ball wire rod and cylindrical grooved cam are extracted and combined, and the variable lead spiral transmission mechanism is obtained. Through the mechanism innovation, the variable lead spiral transmission mechanism has some new characteristics, such as self-adaptability, self-locking, variable lead, hydrodynamic lubrication and so on. These functions are of great significance in practical applications. Considering the parameters and characteristics, the ideal degree model of helical transmission mechanism is established, and the ideal degree of sliding wire rod, rolling wire rod and variable guide wire rod are calculated, and the comparison method of quantitative structure innovation is also given. The mathematical models of the helical groove surface and the general roller profile surface of the wire rod with variable lead and radius are established. The meshing characteristic is analyzed and the gap function is established. Under the condition of invariant radius, the geometric characteristics of the helix with variable lead on the cylinder surface are studied, and the expressions of curvature and torsion are obtained. The helix on the cylindrical surface is optimized by using the arc transition and polynomial transition. According to the extremum condition, the transition curve functional is established and solved by variational principle. Based on the kinematics model of variable lead spiral transmission mechanism, the relative sliding velocity of roller and spiral groove transmission and the conditions for pure rolling are calculated by using coordinate transformation theory and spiral theory. The generalized roller motion parameters are optimized by multi-objective optimization and fuzzy theory. The results are compared with those before optimization and the results are verified. According to Hertz's elastic contact theory, a simplified model of rolling contact of variable lead spiral pair is proposed, and the stress distribution of 3D rolling contact is calculated. The geometric conditions of point contact and line contact between roller and spiral groove are given considering the actual situation and the influence of machining conditions, and the conclusion of point contact is obtained. According to the relationship between the minimum oil film thickness and the roughness and the ellipticity of the contact region, the lubrication state at each contact point is comprehensively judged. The minimum film thickness in the contact process was simulated by Maple software. The variation of the minimum film thickness along the axis of the wire rod was obtained with the change of the minimum film thickness under different leads. The friction and wear mechanism of variable lead screw pair was studied. The specific working conditions of roller and spiral groove contact were analyzed and the load spectrum was compiled by rain flow counting method. Then the fatigue life of the variable lead screw pair is analyzed by using the powerful HyperMesh pre-processing software and the FE-Fatigue fatigue life analysis software. Finally, the influence of various variable lead functions on the fatigue life of screw pair is studied.
【学位授予单位】：南京理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TH132

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