In multi-stage gear transmission system, the accident is often not caused by a single fault, but by coupling fault. The decoupling and identification of coupling faults has always been a hot topic. Through the analysis of frequency characteristics and transmission characteristics, this paper explored the correlation of coupling faults in multistage gear transmission system, and analyzed the coupling mechanism of faults. According to the fault test-bed, a 3D model was built to analyze the contact force and vibration characteristics of gears at all stages. STFT and waterfall diagram were used to analyze the coupling correlation characteristics of experimental signals under two single faults and coupling faults: fixed-axis gear crack and planetary gear wear. The contact force transfer function of all stages of gears to the box was built by using the system identification theory. The source of the fault characteristic frequency component was found through the transfer function, and the transmission characteristic of the fault was revealed. It can be seen from the results that the fault coupling is not the superposition of frequency characteristics. In the coupled signal, the frequency characteristic with the largest amplitude increase is not the fault gear itself, but the intermediate gear connected with them and affected by them. This phenomenon is often misled and misjudged in the analysis.

RV减速器是工业机器人的核心零部件,国产减速器在总体性能上有待提高.对一种新型可替代RV减速器的SG减速器开展测试与分析研究,利用机器人减速器综合测试系统,测试对比SG减速器与RV减速器在空载升速过程中振动、温度、噪声及传动效率等参数的差异,分析SG型减速器的优点与不足,并提出改进方案.研究发现SG减速器在温度、噪声及负载方面更有优势,但在振动及传动效率方面尚待改进.研究结果可为国内新型SG减速器的设计与优化提供参考.

In a multi-stage gear transmission system, the motion state of the system will change with the excitation frequency, and the frequency characteristics will also change accordingly. If this change is not taken into account, there is often a great deviation in identifying and judging system faults according to unified standards, especially when the system has such early undetectable fault as crack. In this paper, the dimensionless differential equations of motion of multistage gear transmission system are established. The stiffness model of gear tooth crack is established by potential energy method. The changes of the motion state of the system with the increase of excitation frequency are obtained by calculating the displacement bifurcation diagram of cracked gear tooth. The influences of crack fault on each motion state are studied by using time domain, frequency domain, phase diagram and Poincaré cross section, and the fault frequency characteristics are summarized. By comparing the theoretical and experimental data of the vibration response characteristics of the system, the motion state of the system can be effectively determined and the crack fault can be identified.

按照GB/Z 18620.2—2008对齿轮副法向侧隙的定义和计算方法,在给定工作中心距的情况下,计算出齿轮副法向侧隙常数c.固定齿轮副中的一个齿轮,利用最大转角测量设备对另一个可转动齿轮的最大转角θ进行测量.齿轮副法向侧隙值由法向侧隙常数c与最大转角θ的乘积计算得出.以测量和计算某发动机用平衡轴总成齿轮副的法向侧隙为例,介绍测量设备,说明该设备可以用于测量封闭空间内齿轮副法向侧隙,并介绍了测量和计算的实现方法.说明测量误差来源并计算出测量误差大小.与塞尺直接测量法的测量结果进行对比,检验基于该方法测量结果的准确性.多次测量同一啮合齿的法向侧隙,确认基于该方法测量结果的一致性.

In order to solve the single machine scheduling problem, and improve the reliability and stability of the equipment, a single machine scheduling model considering piecewise linear deterioration and maintenance unavailability time was established according to the characteristics of continuous fault detection and discrete fault detection. Based on the system reliability theory, the single machine scheduling problem considering machine reliability was studied, and the advantages and disadvantages of maintenance strategy were compared by unified processing of decision conditions. The influence of related parameter changes on production scheduling optimization was determined by single factor and two factor adjustment analysis. The results show that the solution time of the model increases exponentially with the decreasing direction of unit delay cost, and the greater the unit delay cost, the faster the solution speed. The change of delay cost per unit time will not cause a significant change in maintenance cost, and the cost function does not have jumping nodes in flexible periodic maintenance, so it can not be adjusted adaptively. Ratio of preventive maintenance time to fault minor maintenance time has great influence on maintenance decision under discrete detection. The unified processing method of decision conditions can reduce the calculation time and detection cost, and better solve the problems of excessive maintenance or insufficient maintenance in discrete fault detection. These will help to reduce operating costs and improve economic benefits.

In the multistage gear transmission system, when multiple faults are coupled, the faults with weak signals are often hidden and hard to identify. Multi-fault coupling may also cause new coupling fault characteristics, such as new peaks or side bands in the spectrum. These characteristics are likely to contain fault information. Studying the sources of frequency components in coupled fault signals will help to decouple the signals and dig out the correlation characteristics between faults. The coupling fault of fixed-axis gear crack and planetary gear tooth broken was studied in this paper. The nonlinear dynamic model of the multi-stage gear transmission system was used for simulation, and the fault frequency characteristics of the system varying with the excitation frequency were obtained. The short-time Fourier transform (STFT) and waterfall plot analysis were applied to the experimental signals to separate the fault features. By comparing the theoretical and experimental signals, we found the natural frequency of the system, the side frequency characteristics of single fault and coupling fault, and the cause of new peaks. This study has a guiding significance for the separation and identification of coupling faults of the multi-stage gear transmission system.

Nowadays, the demand of “personalization” and “multiple varieties and small batch production” in machining is increasing dramatically. The great challenges of scheduling are brought about by the high flexibility of production and the necessity of equipment maintenance, and the scheduling problems are more complex due to the deteriorating effect of the production process. In order to solve the single machine scheduling problem with step-deteriorating jobs and fixed periodic maintenance strategy, the processing time was described by the piecewise linear function. Based on the properties of the periodic maintenance and the flexible periodic maintenance, two scheduling models were established respectively to minimize the tardiness penalties and maintenance cost. According to the numerical experiments and parameter analysis, the key factors and non-key factors of maintenance decision were determined. The result shows that flexible periodic maintenance has no idle time between adjacent batches. The objective function value increases step by step with the increase of ratio, which can realize “adaptive” adjustment of cost and has significant advantages over fixed cycle maintenance. The construction of a joint scheduling model of production and maintenance can realize the comparison of the advantages and disadvantages of maintenance strategies and the joint decision of production and maintenance, and reduce the operating cost of enterprise production and maintenance.

The test signal of multistage gear transmission system is complex. When coupling faults occur in the system, it is often difficult to accurately extract all kinds of fault features. In the past studies, we found that the fault signals have modulation and coupling effects. The failure of a gear is often reflected in the power spectrum in the form of associated changes in the meshing frequency of other stages. The separation of these features will facilitate the analysis of the coupling effects of multiple faults. The transfer characteristic method provides an effective method for decomposing such signal features. In this paper, through the analysis of transfer characteristics, the coupling fault transfer characteristics and the associated influence relationship of fixed-axis gear crack and planetary gear missing tooth are revealed. The contact force signals of each pair of gears with the coupling fault are obtained by dynamic simulation. The test signals of the fixed-axis gearbox and planetary gearbox are obtained under normal and coupling fault states. According to the method of system identification, the corresponding transfer function model of each path is established. The transfer process is revealed by the analysis of transfer characteristics. The association between two kinds of faults is found, which does not exist in a single fault and is difficult to obtain by signal analysis. This study reveals the association and vibration mechanism of the coupled fault, which provides a theoretical basis for fault diagnosis of multistage gears.

为了降低换挡过程中的二次冲击,提升用户体验,以降低换挡过程中输出端当量转动惯量为思路,文章设计了一款单向离合器式手动变速器.新型变速器将输出轴设计成两段,并以单向离合器相连,全部前进挡齿轮安装在输出轴的前段,与中间轴上各齿轮啮合传动完成变速变扭功能.运用ADAMS仿真软件,对其换挡过程进行动态仿真分析,获得新型手动变速器换挡二次冲击曲线,通过与传统手动变速器换挡二次冲击曲线的对比,揭示了新型手动变速器在提高换挡平顺性方面的优势,并通过仿真分析探究花键齿锁止角及棱线角与换挡二次冲击的关系,通过合理选择锁止角与棱线角数值,进一步降低换挡二次冲击.

With the increasing service life of a gear transmission system, the gear teeth become constantly worn and the gear clearance increases. The increase in the clearance will produce a series of nonlinear changes that change the stability of the system and can even cause the loss of stability. In this paper, dimensionless dynamic equations of a multistage gear transmission system that contains a two-stage fixed-axis gear and a one-stage planetary gear were derived. The wear fault was simulated by changes in the gear clearance. System bifurcation diagrams with an increase in the clearance were studied. The motion state and transition process of the multistage gear transmission system with a wear fault were studied using the Poincaré section. The change in the spectrum characteristics with an increase in the clearance was analyzed. The frequency spectrum characteristics of the wear fault were discovered. The vibration mechanism and a fault wear diagnosis method in a multistage gear transmission system were obtained.

With the increasing service life of a gear transmission system, the gear teeth become constantly worn, and the gear clearance increases. The increase in the clearance will produce a series of nonlinear changes that change the stability of the system and can even result in loss of stability. In this paper, dimensionless dynamic equations of a multistage gear transmission system that contains a two-stage fixed-axis gear and a one-stage planetary gear were established. Planetary wear fault was simulated by changes in the gear clearance. System bifurcation diagrams with an increase in the clearance were studied. The frequency characteristics of planetary gears under different excitation frequencies and different degrees of wear were studied. The influence of planetary gear wear on the fixed-axis was discovered. The vibration mechanism and a fault diagnostic method in a multistage gear transmission system were obtained.

The characteristics of the dislocation axis line contact gear space transmission was analyzed in order to study the new precision gear honing machine prototype which could be clamped and formed at one time, and a pair of dislocation axis involute helical gears in space was designed from the most basic principle of involute gear meshing. The vertical dislocation axis line contact the worm and worm gear (helical gear) transmission mechanism were formed, when two gears had equalent normal base diameter and the sum of their base-circle spiral angles was equal to 90°. According to worm drive relationship of the vertical dislocation axis line contact, the helical gear tooth surface was honed through the worm could be used as a grinding wheel of the honing machine. Grinding wheels with different parameters could be used to machine bevel gears with different modulus, different numbers of teeth and different tooth widths. The finite element analysis and optimization showed that the prototype of the machine tool was reasonable, and the first-order natural frequency is 341.8Hz, which was much higher than the working frequency of 30Hz to avoid resonance.

针对传统油淬工艺不能满足大型齿轮轴畸变要求的情况,运用有限元分析手段找到畸变原因.然后通过改进加热方法和使用盐浴分级淬火工艺,使齿轮轴的畸变大大减小,轮齿中部凹陷量减小至1.41 mm,翘曲减至0.9 mm,能够满足齿轮轴渗碳淬火畸变的技术要求,改善了后期精加工的齿面渗层不均匀现象,大大减少了精加工成本.

Gear tooth surface wear is a common failure mode. It takes a long time and can cause other major faults. The wear fault signal is weak and hard to identify. This paper reveals the transmission characteristics of the planetary gear wear and the relationship between multistage gear meshing through the transmission characteristic analysis. Taking the multistage gear transmission system fault simulation test rig as the research object, a three-dimensional solid rigid-flexible coupling model of the system was established. The contact force signals from each pair of gears in the state of planetary gear wear were obtained by dynamic simulation. The test signals of the fixed-axis gearbox and planetary gearbox were obtained under normal and planetary gear wear states. Comparing the transmission characteristics of the system under normal and planetary gear wear states, the vibration mechanism of the wear fault and the correlative characteristic between gearboxes were revealed.

变齿厚内齿轮鼓形蜗杆传动是一种新型蜗杆传动,它由变齿厚内齿轮和利用包络形成的鼓形蜗杆两部分组成.它具有体积小、重量轻、结构紧凑以及大传动比等特点,在机器人智能关节领域有着广阔的应用前景.蜗杆传动在工作时会产生大量的热,同时电机置于蜗杆内部也会产生大量的热,使蜗轮蜗杆发生变形,产生热应力.为了掌握内齿轮包络鼓形蜗杆传动副的热应力分布及其热变形情况,探讨温度对最大应力的影响,做了以下研究.首先,利用微分几何与啮合理论通过Creo建立齿面数学模型;其次,将模型导入AnsysWorkbench中对其进行热分析和热力学分析;最后,利用参数化设计的方法,分析出在特定结构载荷的作用下,温度对蜗轮蜗杆的最大等效应力的影响,并得出最大应力与温度变化的关系曲线.

渗碳淬火是高参数硬齿面齿轮表面强化热处理的主要工艺方法.该工艺过程复杂,影响因素较多,尤其是该过程中齿轮畸变的控制是其突出的技术难点之一.鉴于传统方法的缺陷和计算机模拟技术的发展,对齿轮渗碳淬火过程及其畸变的数值模拟成为当前行业的发展前沿.本文阐述了齿轮渗碳淬火及其畸变数值模拟的数学模型、操作平台和研究现状,并展望了今后的发展方向.

针对风电机组齿轮箱系统的故障预测问题,利用了齿轮箱异常时的动态特性将会偏离正常工作状态的现象,提出了同时使用温度和压力信号对齿轮箱进行故障预测,并据此建立了一种齿轮箱的温度和压力模型.采用了滑动窗口法计算残差的分布特性,以天为单位,定义了残差超限比例,根据预测值残差分布特性的改变,对齿轮箱故障做出及时的预测;设计了以残差超限比例为依据,向风电场发起报警信息的系统流程,提示运维人员有针对性地对设备进行检查;通过对现场实际机组进行模型部署试验,实现了对齿轮箱温控阀故障的提前预警.研究结果表明:该模型对齿轮箱异常状态的判断能力可以起到提前预警的目的.

变齿厚内齿轮包络鼓形蜗杆传动是一种新型蜗杆传动,由变齿厚内齿轮及其包络形成的鼓形蜗杆所组成.运用零间隙法分析计算在误差情况下该传动副接触点的偏移量和误差影响矩阵,得到了误差对该传动副接触点的影响规律.结果表明:单因子误差下,母平面倾角与轴间角误差、喉径系数与基圆半径误差、中心距与蜗杆轴向位移误差、蜗轮轴向位移误差的影响对接触线的影响依次减小.

To identify the fault frequency characteristics of the gear transmission system under coupling fault of fixed-axis gear crack and planetary gear wear, dimensionless dynamical equations of gear transmission system were established. Bifurcations in normal condition and coupling fault condition were contrasted. The affected excitation frequency range was found. Fault frequency characteristics in sensitive interval caused by the coupling fault of fixed-axis gear crack and planetary gear wear were analyzed. Simulation analysis shows that the crack fault in fixed-axis gear brings up peaks in doubling of 1~10 for fault frequency, the wear fault in planetary gear increases the amplitude of meshing frequency and its double and triple, and the coupling of both shows two kinds of fault features around the planetary gear meshing frequency.

The sub-harmonic resonance phenomenon exists in multistage gear transmission system. Collision motion leads the sub-harmonic resonance instability, which brings harm to system stability. So investigating instability conditions of sub-harmonic resonance and effects of fault on stability have important significance on controlling system stability. From the point of view of nonlinear dynamics, dimensionless dynamical equations of multistage gear transmission system which contains a two-stage fixed-axis gear and a one-stage planetary gear are established. The bifurcation diagrams of system are obtained. By the changing of Poincaré section analyze the evolution process of sub-harmonic resonance and instability conditions. The changes of sub-harmonic resonance and system stability are studied under fixed-axis gear tooth crack fault state in different clearance. The study has important significance for operational prediction of system.