直齿行星齿轮动力学建模与分析研究

建立了直齿行星齿轮的动力学模型.其中,齿与齿之间的啮合非线性由弹簧-阻尼器-间隙-啮合误差环节模拟.提出了一种以行星轮转角为变量的时变啮合刚度与时变啮合误差表达形式,解决了变转速下行星齿轮动力学模型的描述和求解问题.通过对动力学模型进行求解,分别研究了转速、齿侧间隙、啮合误差和负载等重要参数对行星齿轮动力学特性的影响.     

基于微分进化算法的非对称弧齿锥齿轮约束多目标优化

根据齿轮啮合原理和现代摩擦学理论,建立了以弧齿锥齿轮传动齿面上瞬时接触线方向与相对滑动速度之间夹角的余切值最小、传动总体积最小和齿面诱导法曲率主值最小为目标函数的约束多目标优化设计数学模型。对当前的微分进化多目标优化算法进行了改进,给出了适用于工程领域的微分进化约束多目标优化算法。借助于改进的微分进化多目标优化算法,通过范例对弧齿锥齿轮传动进行两目标和三目标优化设计。分析了齿面上瞬时接触线方向与相对滑动速度之间的夹角及齿面诱导法曲率主值对齿面接触强度和胶合强度的影响。     

基于传动误差数据的齿轮误差检测方法与系统

齿轮传动误差影响齿轮传动精度和平稳性,传动误差与齿距和齿廓偏差等齿轮误差数据有直接关系.利用单面啮合测试和虚拟仪器原理,构建了传动误差检测系统,研究了传动误差与齿距与齿廓偏差数据的关系,找到一种将齿距与齿廓偏差计算出来的方法.经过试验分析,验证了本方法和系统的准确性.     

考虑摩擦剥落故障的直齿轮副啮合刚度研究

针对直齿轮副从动轮轮齿由于受到交变与热应力载荷而发生点蚀剥落故障时齿轮副时变啮合刚度变化问题,本文选取矩形剥落区域简化计算,建立齿轮副齿面剥落的物理模型,以势能法推导当发生非对称剥落故障时齿轮副传动任意时刻的啮合刚度;同时通过建立齿面摩擦模型,研究了基于定摩擦因数下和时变摩擦因数下齿面摩擦和点蚀剥落故障对齿轮副啮合刚度的综合影响,推导考虑齿面摩擦的剥落故障齿轮副啮合刚度计算解析式。研究结果表明,当齿轮发生非对称齿面剥落故障时,轮齿因发生扭转变形而产生扭转刚度,齿轮副啮合刚度减小;齿面摩擦对啮合刚度影响较为复杂,其会增加直齿轮副双齿啮合区间和单齿啮合区间啮入阶段的啮合刚度,减小单齿啮合区间啮出阶段的啮合刚度。     

某电动机构齿轮副静态接触与动力学仿真

某电动机构在工作过程中发现齿轮传动中心距超差并发生齿轮副传动失效故障,需要分析中心距超差对齿轮传动失效的影响.传统赫兹理论的推导存在许多假设,存在一定局限性.为了获得更加准确的结果,对故障齿轮副进行了有限元静态接触分析和动力学仿真分析.通过有限元静态接触分析获得了某电动机构故障齿轮副啮合过程中的齿面接触力与等效应力情况,通过动力学仿真获得了不同中心距条件下齿轮副传动过程中的角速度、角加速度及接触力的动态过程.结果表明,中心距的超差使输出转速的波动明显增大,使角加速度的峰值增大并引起了高频振动,同时使最大齿面接触应力增大,进而导致了某电动机构齿轮副的失效.     

双不确定参数作用下双稳态能量采集系统的随机响应分析

为改善纯电动汽车齿轮传动在整个工况范围内的工作性能,提出一种计及负载扭矩和转速工况影响的齿面修形方法.考虑时变啮合刚度、啮合冲击、齿面摩擦激励,建立了系统动力学分析模型.结合轮齿几何接触分析和承载接触分析,采用遗传算法优化获得全工况最优的齿廓、齿向抛物线修形系数,并对比分析了不同修形方案的抑振效果.结果表明：计及工况影响的齿面修形在全工况下的振动加速度均方根都保持在较低水平,说明这一齿面修形策略具有更好的全局抑振效果.     

纯电动汽车高速齿轮传动全工况抑振修形方法

为改善纯电动汽车齿轮传动在整个工况范围内的工作性能,提出一种计及负载扭矩和转速工况影响的齿面修形方法.考虑时变啮合刚度、啮合冲击、齿面摩擦激励,建立了系统动力学分析模型.结合轮齿几何接触分析和承载接触分析,采用遗传算法优化获得全工况最优的齿廓、齿向抛物线修形系数,并对比分析了不同修形方案的抑振效果.结果表明：计及工况影响的齿面修形在全工况下的振动加速度均方根都保持在较低水平,说明这一齿面修形策略具有更好的全局抑振效果.     

等变位节点外啮合齿轮传动性能分析

从轮齿的接触强度、弯曲强度、磨损、振动、润滑等方面对等变位节点外啮合齿轮传动性能进行了分析,指出这类齿轮传动在特定工况下的一些优点.     

弧齿锥齿轮动态啮合质量的优化设计

在齿轮的啮合质量优化问题的研究中,针对弧齿锥齿轮动态啮合参数人为设定问题,需设计者具有足够的先验知识,造成花费时间多次反复.为进一步提高优化质量,根据改进粒子群优化算法提出了一种全局优化思路.利用TCA与LTCA技术,以局部综合法中的预设啮合参数为优化设计变量,以无载传动误差曲线的对称度、承载传动误差的下限与无载传动误差下限之间的距离及承载传动误差的均方差为优化目标函数,从设计和加工角度对弧齿锥齿轮的动态啮合质量进行了全局优化设计.仿真结果表明,方法简单有效,真实可靠,对提高弧齿锥齿轮的动态啮合质量优化提供了有效依据.     

齿轮误差快速测量系统的设计

介绍了齿轮误差快速测量系统的软、硬件设计。该系统采用啮合滚动式综合测量方法,将被测齿轮作为一个回转运动的传动元件,在理论安装中心距下与标准齿轮作啮合转动,在此过程中来测量齿轮误差。试验测试结果验证了该系统的精度。     

Application of modified geometry of face gear drive

An enhanced approach for the application of longitudinal plunging in the manufacturing of a double crowned pinion of a face gear drive has been investigated, with the purpose of reducing the sensitivity of the gear drive to misalignments. The process of manufacturing is based on a modification of the movements applied to the grinding disk during the generation of the surfaces of the pinion, consisting in the introduction of a tilt of the plane that contains the planar trajectory performed by the center of the disk. Tooth contact analysis and stress analysis have been considered to simulate the contact and meshing of the gear tooth surfaces and to calculate the evolution of contact and bending stresses of the gear drive along the cycle of meshing. The performed research proves that an appropriate choice of the machine tool settings permits the avoidance of edge contact, in presence of misalignment as well, without a high reduction of the contact ratio. The results are illustrated with numerical examples.     

An innovative approach to NC programming for accurate five-axis flank milling of spiral bevel or hypoid gears

To transfer power, a pair of spiral bevel or hypoid gears engages. From beginning to end of two tooth surfaces engaging with each other: for their rigid property, they contact at different points; and for their plastic property, they contact at small ellipses around the points. On each surface, the contact line (or called as contact path) by connecting these points and the contact area by joining these ellipses are critical to driving performance. Therefore, to machine these surfaces, it is important to machine the contact line and area with higher accuracy than other areas. Five-axis flank milling is efficient and is widely used in industry. However, tool paths for flank milling the gears, which are generated with the existing methods, can cause overcuts on the contact area with large machining errors. To overcome this problem, an innovative approach to NC programming for accurate and efficient five-axis flank milling of spiral bevel or hypoid gears is proposed. First, the necessary conditions of the cutter envelope surface tangent with the designed surface along a designed line are derived to address the overcut problem of five-axis milling. Second, the tooth surface including the contact line and area are represented using their machining and meshing models. Third, according to the tooth surface model, an optimization method based on the necessary conditions is proposed to plan the cutter location and orientation for flank milling the tooth surface. By using these planned tool paths, the overcut problem is eliminated and the machining errors of contact area are reduced. The proposed approach can significantly promote flank milling in the gear manufacturing industry.     

Precise Design and Stress Analysis of Straight Conical Gear

1 Introduction Straight conical gears are widely used in power transmission between perpendicular shafts. In the last few decades, there has been a growing interest in conical involute gears. Apart from being frequently used in anti-backlash schemes, they are, according to Mitome, also used as reduction gears[1], miter gears, trimming gears and differential gears. The conical involute gear, which is also called beveloid gear by some authors, is an involute gear with tapered tooth thickness, t…     

Tooth flank modification theory of dual-torus double-enveloping hourglass worm drives

In this paper, the theory of tooth flank modification is enriched and developed for a double-enveloping toroidal worm drive. The goal and significance of the modification are expounded from the point of view of changing the tooth flank configuration for the worm gear pair. It is pointed out that the constant center distance modification, the constant transmission ratio modification, and the combination of the previous two are the convenient and reasonable modification strategies. All the corrected hourglass worm pairs, attained by employing the preceding modification methodology, can be divided into two fundamental types: the type I worm pair and the type II worm pair, from the perspective of the meshing behavior. The division criterion of the worm drive type is moreover provided on the basis of the value range of the modification parameters in this study. The meshing characteristics of the two types of the modified globoidal worm drive are summarized in detail. The results indicate that the type II worm gearing with slight modification should be the preferred style for the double-enveloping toroidal worm drive.     

Face-gear drive with spur involute pinion: geometry,generation by a worm,stress analysis

A face-gear drive with a spur involute pinion is considered. The generation of the face gear is based on application of a grinding or cutting worm whereas the conventional method of generation is based on application of an involute shaper. The authors have developed an analytical approach for determination of: (i) the worm thread surface, (ii) avoidance of singularities of the worm thread surface, (iii) dressing of the worm, and (iv) determination of stresses of the face-gear drive. A computer program is developed for simulation of meshing and contact of the pinion and face gear. Correction of machine-tool settings is proposed for reduction of the shift of the bearing contact caused by misalignment. An automatic development of the model of five contacting teeth has been proposed for stress analysis. Numerical examples for illustration of the developed theory are provided.     

Rigid-elastic modeling of meshing gear wheels in multibody systems

In many applications in mechanical engineering, gear wheels are used to transmit power between rotating shafts and, therefore, the ability to incorporate them into multibody systems and to simulate contact between them has become an essential topic in multibody dynamics.However, in some applications gear wheels may not be considered as being perfectly rigid. Due to the effect of contact forces there occur relevant deformations in meshing teeth and it is required for a high quality of the analysis to introduce some elasticities in the model of meshing gear wheels. Therefore, in this work elastic elements between the teeth and the body of each gear wheel are considered. This approach is especially well suited for multibody systems since it is a compromise between a totally rigid model and a fully elastic model allowing the simulation of large motions with many revolutions while still important elasticities are considered. The teeth and the body of each gear wheel are still modelled as being rigid but they are connected to each other by elastic elements. In doing so, an efficient and physically motivated algorithm is described and implemented in order to find the effects of multi-tooth contact as well as backlash and left and right hand side contact of the meshing teeth. Some examples compare the simulation results of rigid, partially elastic and fully elastic models.     

Generalized concept of meshing and contact of involute crossed helical gears and its application

A general approach for generation and design of standard and non-standard involute crossed helical gears is proposed. The conjugation of gear tooth surfaces is based on application of two generating rack-cutters with a common normal section. The investigation of the geometry is based on a new approach for presentation of the line of action A (the line of points of contact of tooth surfaces). Line A is represented in a plane Π that is tangent to the pinion base cylinder and position of A is determined analytically. Edge contact of tooth surfaces is avoided by limitation of shift of line of action caused by errors Δγ and ΔE of the crossing angle and the shortest distance, respectively. Simulation of meshing and contact is computerized by developed computer program. Enhanced stress analysis approach is proposed. The developed theory is illustrated with numerical examples.