研齿的修形机理与试验研究

研究了螺旋锥齿轮齿面综合研磨率、动态互研与研齿修形机理。动态研磨力在螺旋锥齿轮研磨中起着微切削与均化误差的作用，使齿面尖点、高点与齿对转换点首先得到研磨。研齿的修形作用趋于使二次抛物线形传动误差曲线高阶化，传动误差曲线上部平坦，转换点平滑过渡。通过引入相对螺旋角误差与相对压力角误差的概念，对齿形与齿距误差进行了测量，从而评价了轮齿研齿前后的实际啮合精度。对啮合振动、噪声进行了对比试验，结果表明，研齿能明显改善齿轮副的啮合精度与动态性能。     

超声激励下弧齿锥齿轮研齿系统动态研磨力分析

在综合考虑超声激励和齿面几何传动误差激励的情况下，建立了有间隙的两自由度周向振动的弧齿锥齿轮研齿动力学模型，得到了齿面间动态研磨力的计算公式。通过算例分析表明，与普通研齿效果对比，超声激励增大了齿面间的动态研磨力，使齿面在啮合过程中出现了碰撞，当超声激励振幅值为16．5N·m时，超声研齿系统由周期运动进入到混沌状态。     

超声研齿不灵敏性振动切削机理与实验

提出了超声研磨螺旋锥齿轮的理论与方法。分析了超声研齿不灵敏性振动切削机理。超声振动使研磨切削抗力减小,动态啮合精度提高,因此,使研磨效率与齿面质量得到相应提高。进行了普通与超声研齿对比试验表明,超声研齿材料去除率可达到普通研磨的三倍,齿面微切削与塑性流动纹理明显,点蚀深度、划痕长短均匀,齿面质量明显优于普通研磨齿面,即粗糙度低至0.2μm,轮廓支承长度率Rmr(c)=100%,水平截距c=1.2μm。     

齿面研磨边界的确定与研齿性能试验

通过对研齿过程的轮齿接触仿真,传动误差与重合度的分析,确定了齿面研磨区域的边界:距齿面中点±0.25～0.3个齿宽,±0.1～0.25个齿高.通过研齿试验,研究了研磨对齿面接触印痕、齿形精度与动态啮合性能的影响.结果表明,研齿能一定程度上消除齿形误差,改善轮齿接触区位置与形状,使热处理后变形的接触区一定程度上得到恢复;研齿对齿轮副动态性能改善明显,振动噪声在转速、载荷较宽的范围内均有明显下降.     

动态力研齿新工艺

研究了一种硬齿面以研代磨新工艺，应用动态研磨和误差均化理论，并经大量实验，取得了阶段性成果。     

齿面综合研磨率分析与研齿性能试验

首次通过对研齿过程的轮齿接触仿真,齿面瞬时接触应力、齿面滑动系数与齿面研磨概率的研究分析,建立了齿面综合研磨率的评价指标,并进行了研齿性能试验。结果表明,准双曲面齿轮齿面中部研磨要严重一些,靠齿根稍重些,靠齿顶稍轻些,这与传动误差变化规律一致。研齿能一定程度上降低齿形、齿距误差,尤其对轮齿的实际啮合精度改善明显,振动噪声均有较大下降。     

齿轮动力互研法的工艺研究

齿轮动力互研法是利用齿面动态力达到齿轮精加工目的的方法。为了避免出现齿面“中凸”及齿根部研磨较严重的现象,采用了变中心距研齿工艺。通过对齿面诱导法曲率和齿面滑动系数的分析,说明采用变中心距研齿比定中心距研齿,其齿面研磨的一致性有很大的改善,这对提高研齿精度是非常有利的。     

基于多体系统理论的螺旋锥齿轮误差齿面建立与分析

根据六轴五联动螺旋锥齿轮磨床结构,应用多体系统理论、齿轮啮合理论建立了含几何误差、热误差的螺旋锥齿轮误差齿面模型,并仿真了砂轮主轴分别沿X、Y轴平移和绕C轴旋转时,螺旋锥齿轮理论与误差齿面.仿真结果表明,砂轮主轴绕C轴旋转对齿面误差影响较大.文章研究对提高螺旋锥齿轮的加工精度和误差补偿提供了理论依据.     

螺旋锥齿轮振动研磨的运动模型研究与分析

首次提出螺旋锥齿轮振动复合研齿法 ,建立了V/H与齿面啮合关系的数学模型与振动研齿法的运动学模型。利用TCA方法 ,通过对齿面的接触路径与印痕、齿面相对运动速度与研磨轨迹、切削速度数值仿真 ,证明该模型能对齿面研磨中接触路径与印痕进行准确的控制 ,振动研磨加工的质量效率明显优于传统方法     

螺旋锥齿轮误差齿面及差曲面的建立与分析

针对六轴五联动螺旋锥齿轮磨床结构,应用多体系统理论、齿轮啮合理论,建立了含几何误差、热误差的螺旋锥齿轮误差齿面与差曲面模型并进行了实验验证,仿真分析了砂轮分别沿X轴、Y轴平移时和绕C轴旋转时,螺旋锥齿轮理论齿面与误差齿面以及它们的差曲面。结果表明,砂轮绕C轴旋转所产生的运动副误差对齿面误差影响较大。研究结果对提高螺旋锥齿轮的加工精度和进行误差补偿提供了理论依据。        

齿轮光整加工新工艺--动态力互研法

对渐开线齿轮动态力研齿进行了理论分析和实验研究。基于以研代磨的设想,齿轮动态力研齿将研磨工艺用于硬齿面粉加工,其加工原理为,两被研齿轮在空载下以确定的速比,大转动惯量下高速稳态运转,研齿时保持速比不变,并周期性改变两齿轮的中心距,利用齿轮啮合时齿轮本身误差产生的齿面动态力,在研磨剂的作用下,修整齿轮误差达到两齿轮提高精度的目的。     

Elastodynamic analysis of a gear pump. Part I: Pressure distribution and gear eccentricity

A non-linear lumped kineto-elastodynamic model for the prediction of the dynamic behaviour of external gear pumps is presented. It takes into account the most important phenomena involved in the operation of this kind of machines. Two main sources of noise and vibration can be considered: pressure and gear meshing. Fluid pressure distribution on gears, which is time-varying, is computed and included as a resultant external force and torque acting on the gears. Parametric excitations due to time-varying meshing stiffness, the tooth profile errors (obtained by a metrological analysis), the backlash effects between meshing teeth, the lubricant squeeze and the possibility of tooth contact on both lines of action were also included. Finally, the torsional stiffness and damping of the driving shaft and the non-linear behaviour of the hydrodynamic journal bearings were also taken into account. Model validation was carried out on the basis of experimental data concerning case accelerations and force reactions. The model can be used in order to analyse the pump dynamic behaviour and to identify the effects of modifications in design and operation parameters, in terms of vibration and dynamic forces.Part I is devoted to the calculation of the gear eccentricity in the steady-state condition as a result of the balancing between mean pressure loads, mean meshing force and bearing reactions, while in Part II the meshing phenomena are fully explained and the main simulation results are presented.     

Elastodynamic analysis of a gear pump. Part II: Meshing phenomena and simulation results

A non-linear lumped kineto-elastodynamic model for the prediction of the dynamic behaviour of external gear pumps is presented. It takes into account the most important phenomena involved in the operation of this kind of machines. Two main sources of noise and vibration can be considered: pressure and gear meshing. Fluid pressure distribution on gears, which is time-varying, is computed and included as a resultant external force and torque acting on the gears. Parametric excitations due to time-varying meshing stiffness, the tooth profile errors (obtained by a metrological analysis), the backlash effects between meshing teeth, the lubricant squeeze and the possibility of tooth contact on both lines of action were also included. Finally, the torsional stiffness and damping of the driving shaft and the non-linear behaviour of the hydrodynamic journal bearings were also taken into account. Model validation was carried out on the basis of experimental data concerning case accelerations and force reactions. The model can be used in order to analyse the pump dynamic behaviour and to identify the effects of modifications in design and operation parameters, in terms of vibration and dynamic forces.Part I is devoted to the calculation of the gear eccentricity in the steady-state condition as result of the balancing between mean pressure loads, mean meshing force and bearing reactions, while in Part II the meshing phenomena are fully explained and the main simulation results are presented.     

齿轮动态力互研法工艺研究*

对渐开线齿轮动态力研齿进行了理论分析和试验研究。基于以研代磨的设想，齿轮动态力研齿将研磨工艺用于硬齿面精加工，其加工原理为：两工件齿轮（两被研齿轮）在空载下以确定的速比（两齿轮的齿数比），在大转动惯量下高速稳态运转，研齿时保持两齿轮的速比不变，并周期性改变两齿轮的中心距，利用齿轮啮合时，齿轮本身误差产生的齿面动态力在研磨剂的作用下，修整齿轮误差达到两齿轮提高精度的目的。     

含侧隙齿轮副的动载荷分析

以振动理论为基础，提出一种考虑齿轮拍击振动的齿轮动载荷的数值计算方法。建立计算动载荷的齿轮冲击模型，在模型中考虑了齿轮正、反冲击时实际的啮合刚度，并给出啮合柔度的计算方法。分析在考虑静态传递误差、啮合刚度、侧隙、摩擦力及外部扭矩变化等多种激励时，作用在轮齿上的动态载荷以及整个齿轮上的综合动态载荷的计算公式。最后通过实例分析作用在轮齿上的动态载荷、综合动态载荷变化规律以及相关激励参数对动态载荷的影响。     

Performance improvement method for Nylon 6 spur gears

Plastic gears made of Nylon 6 are especially susceptible to failure due to extreme heat accumulation in the single tooth mesh area, which results in damage that consequently shortens gear teeth life and causes transmission errors. In this experimental study, the teeth width of plastic spur gears made of Nylon 6 were modified and investigated. The values of load sharing, F/b, in single and double tooth meshing areas were leveled by widening the single tooth zone along the meshing area, and the performances of both modified and unmodified gears were studied experimentally under three different loadings. It was observed that modified Nylon 6 gears exhibit lower tooth temperatures, which results in a decrease in wear rate as compared to unmodified gears. Consequently, teeth width modification helps to increase Nylon 6 gear performance.     

Simulation of wear in gears with flank interference—a mixed FE and analytical approach

Gears in precision mechanisms, such as industrial robots, are often designed to have no backlash. Deviations from the ideal gear geometries and unfavourable deformations during operation may cause interference between interacting tooth flanks, resulting in high and strongly varying friction. Mild wear of the tooth flanks may improve such conditions. Therefore, this theoretical study has been conducted of wear in spur gears with interference. A mixed finite element (FE) and analytical approach is used. The FE method is used to determine contact loads between the interacting gear teeth. The main drawback with FE analyses of this type of problem is normally the computation time needed. Therefore, a novel FE meshing method is used, giving a dense FE mesh in the contact regions and a coarse mesh in the rest of the teeth. Based on the FE determined loads between the interacting teeth, the contact pressures and the contact widths are then easily determined using analytical expressions based on Hertz theory. The wear of a point on a tooth flank is determined by integrating the product of sliding distance and contact pressure during the time it is in contact with its mating flank.The results show that the wear of the gear tooth flanks may eliminate the interference and consequently the high and strongly varying friction will decrease dramatically. However, the transmission error will change, since the gears will not preserve their accurate involute profiles.