Torque effect on vibration behavior of high-speed train gearbox under internal and external excitations

The high-speed train transmission system,experiencing both the internal excitation originating from gear meshing and the external excitation originating from the wheel-rail interaction,exhibits complex dynamic behavior in the actual service environment.This paper focuses on the gearbox in the high-speed train to carry out the bench test,in which various operat-ing conditions(torques and rotation speeds)were set up and the excitation condition covering both internal and external was created.Acceleration responses on multiple positions of the gearbox were acquired in the test and the vibration behavior of the gearbox was studied.Meanwhile,a stochastic excitation modal test was also carried out on the test bench under different torques,and the modal parameter of the gearbox was identified.Finally,the sweep frequency response of the gearbox under gear meshing excitation was analyzed through dynamic modeling.The results showed that the torque has an attenuating effect on the amplitude of gear meshing frequency on the gearbox,and the effect of external excitation on the gearbox vibration cannot be ignored,especially under the rated operating condition.It was also found that the torque affects the modal param-eter of the gearbox significantly.The torque has a great effect on both the gear meshing stiffness and the bearing stiffness in the transmission system,which is the inherent reason for the changed modal characteristics observed in the modal test and affects the vibration behavior of the gearbox consequently.

Advancing high-speed train gearbox durability:enhanced bearing load and contact stress through transition from helical to herringbone gears

High-speed trains typically utilize helical gear transmissions,which significantly impact the bearing load capacity and fatigue service performance of the gearbox bearings.This paper focuses on the gearbox bearings,establishing dynamic models for both helical gear and herringbone gear transmissions in high-speed trains.The modeling particularly emphasizes the precision of the bearings at the gearbox's pinion and gear wheels.Using this model,a comparative analysis is conducted on the bearing loads and contact stresses of the gearbox bearings under uniform-speed operation between the two gear transmissions.The findings reveal that the helical gear transmission generates axial forces leading to severe load imbalance on the bearings at both sides of the large gear,and this imbalance intensifies with the increase in train speed.Consequently,this results in a significant increase in contact stress on the bearings on one side.The adoption of herringbone gear transmission effectively suppresses axial forces,resolving the load imbalance issue and substantially reducing the contact stress on the originally biased side of the bearings.The study demonstrates that employing herringbone gear transmission can significantly enhance the service performance of high-speed train gearbox bearings,thereby extending their service life.

Investigation on influencing factors of wheel polygonization of a plateau high-speed EMU train

Purpose–This study aims to investigate the cause of high-order wheel polygonization in a plateau high-speed electric multiple unit(EMU)train.Design/methodology/approach–A series of field tests were conducted to measure the vibration accelerations of the axle box and bogie when the wheels of the EMU train passed through tracks with normal rail roughness after re-profiling.Additionally,the dynamic characteristics of the track,wheelset and bogie were also measured.These measurements provided insights into the mechanisms that lead to wheel polygonization.Findings–The results of the field tests indicate that wheel polygonal wear in theEMUtrain primarily exhibits 14–16 and 25–27 harmonic orders.The passing frequencies of wheel polygonization were approximately 283–323 Hz and 505–545 Hz,which closely match the dominated frequencies of axle box and bogie vibrations.These findings suggest that the fixed-frequency vibrations originate from the natural modes of the wheelset and bogie,which can be excited by wheel/rail irregularities.Originality/value–The study provides novel insights into the mechanisms of high-order wheel polygonization in plateau high-speed EMU trains.Futher,the results indicate that operating the EMU train on mixed lines at variable speeds could potentially mitigate high-order polygonal wear,providing practical value for improving the safety,performance and maintenance efficiency of high-speed EMU trains.

Measured load spectra of the bearing in high-speed train gearbox under different gear meshing conditions

The load spectrum is a crucial factor for assess-ing the fatigue reliability of in-service rolling element bear-ings in transmission systems.For a bearing in a high-speed train gearbox,a measurement technique based on strain detection of bearing outer ring was used to instrument the bearing and determine the time histories of the distributed load in the bearing under different gear meshing conditions.Accordingly,the load spectrum of the total radial load car-ried by the bearing was compiled.The mean value and class interval of the obtained load spectrum were found to vary non-monotonously with the speed and torque of gear mesh-ing,which was considered to be caused by the vibration of the shaft and the bearing cage.As the realistic service load input of bearing life assessment,the measured load spectrum under different gear meshing conditions can be used to pre-dict gearbox bearing life realistically based on the damage-equivalent principle and actual operating conditions.

Dynamic Response Analysis of High-Speed Train Gearbox Housing Based on Equivalent Acceleration Amplitude Method

Gearbox, as the crucial transmission equipment of high-speed train drive system, bears mainly the impact of wheel-rail excitation during its application, resulting in fatigue failure of the housing structure. In order to analyze the vibration characteristics of the high-speed train gearbox housing, a test had been performed under operating condition on Wuhan-Guangzhou High-Speed Railway, where a host of vibration characteristics of different parts of housing had been obtained, and vibration signals had also been comparatively analyzed using acceleration amplitude spectrum and equivalent acceleration amplitude method. The result showed that the vibration level of the measuring point A on the joint part of the gearbox housing and axle bearing block was higher than that of the measuring point B on the upper part of the gearbox housing, both horizontally and vertically. And there existed attenuation during the transmission process of vibration from point A to Point B. Further, when a train was moving at a high speed, the gearbox vibration at the head carriage was better than that at the tail carriage. In addition, when a train slowed down from 300 km/h to 200 km/h, the horizontal equivalent acceleration amplitude dropped by 58% while the vertical one declined by 62%. Equivalent acceleration amplitude method was used to identify the vibration relations among different parts of housing, and the validity and applicability of this method were verified by data analysis. The study provided reference to ensure the operating safety of high-speed train drive system and design of new housing structure.

Analysis of vibration and frequency transmission of high speed EMU with flexible model

When the operation speed of the high-speed train increases and the weight of the carbody becomes lighter,not only does the sensitivity of the wheel/rail contact get higher,but also the vibration frequency range of the vehicle system gets enlarged and more frequencies are transmitted from the wheelset to the carbody.It is important to investigate the vibration characteristics and the dynamic frequency transmission from the wheel/rail interface to the carbody of the high-speed electric multi-uint（EMU）.An elastic highspeed vehicle dynamics model is established in which the carbody,bogieframes,and wheelsets are all dealt with as flexible body.A rigid high-speed vehicle dynamics model is set up to compare with the simulation results of the elastic model.In the rigid vehicle model,the carbody,bogieframes and wheelsets are treated as rigid component while the suspension and structure parameters are the same as used in the elastic model.The dynamic characteristic of the elastic high speed vehicle is investigated in time and frequency domains and the di ff erence of the acceleration,frequency distribution and transmission of the two types of models are presented.The results show that the spectrum power density of the vehicle decreases from the wheelset to the carbody and the acceleration transmission ratio is approximately from 1%to 10%for each suspension system.The frequency of the wheelset rotation is evident in the vibration of the flexible model and is transmitted from the wheelset to the bogieframe and to thecarbody.The results of the flexible model are more reasonable than that of the rigid model.A field test data of the high speed train are presented to verify the simulation results.It shows that the simulation results are coincident with the field test data.

Improved fault location method for AT traction power network based on EMU load test

The autotransformer(AT)neutral current ratio method is widely used for fault location in the AT traction power network.With the development of high-speed electrified railways,a large number of data show that the relation between the AT neutral current ratio and the distance from the beginning of the fault AT section to the fault point(Q-L relation)is mostly nonlinear.Therefore,the linear Q-L relation in the traditional fault location method always leads to large errors.To solve this problem,a large number of load-related current data that can be used to describe the Q-L relation are obtained through the load test of the electric multiple unit(EMU).Thus,an improved fault location method based on the back propagation(BP)neural network is proposed in this paper.On this basis,a comparison between the improved method and the traditional method shows that the maximum absolute error and the average absolute error of the improved method are 0.651 km and 0.334 km lower than those of the traditional method,respectively,which demonstrates that the improved method can effectively eliminate the influence of nonlinear factors and greatly improve the accuracy of fault location for the AT traction power network.Finally,combined with a shortcircuit test,the accuracy of the improved method is verified.

Variation in contact load at the most loaded position of the outer raceway of a bearing in high-speed train gearbox

For the fatigue failure and tribological property of a rolling element bearing,the contact load variation plays a significant role while the most loaded position of the bearing outer raceway takes the greatest risk of failure.This paper focuses on the variation in contact load on the most loaded position of the outer raceway of a gearbox bearing in high-speed train.Under operation conditions of different input speeds and torques,the dynamic contact load distribution in a gearbox bearing of high-speed train was measured by instrumenting the bearing with strain gauges.The most loaded position was identified accordingly and the features and reasons of the variation in contact load on this position were suggested.Three factors were found to have varying degrees of impact on the contact load variation under different gear meshing conditions:modal vibration of the cage or shaft,radial geometrical differences among the rollers and vibration of the gearbox housing.

基于随机森林算法的动车组传动齿轮修形研究

动车组齿轮传动过程中存在齿轮啮合冲击,加剧了齿轮箱的振动,影响齿轮箱服役安全。为此,文章在SIMPACK中建立了含有齿轮传动系统的某动车刚柔耦合动力学模型,搭建了SIMPACK-ISIGHT仿真平台,计算了传动齿轮最佳修形参数,研究了其对齿轮箱振动的优化效果。以齿轮箱在动车速度为200 km/h、250 km/h、300 km/h和350 km/h时的振动加速度均方根值为响应进行了试验设计,试验结果表明,齿轮修形参数的变化对齿轮箱垂向振动加速度影响较大,而对横向振动加速度影响较小。基于随机森林算法建立代理模型,采用NSGA-Ⅱ算法调用代理模型进行了齿轮修形参数的寻优计算,将齿轮箱垂向振动加速度均方根值减小量作为优化率,以各速度下优化率的加权平均值为优化目标。优化结果表明:齿轮修形对各速度时的齿轮箱垂向振动加速度均方根值均有所优化,随着速度增加齿轮修形对齿轮箱垂向振动的优化效果逐渐变差。最后,以平均分配权重所得的齿轮修形参数为例,对比齿轮修形前后齿轮箱垂向振动加速度的变化。计算结果表明:在时域上,齿轮修形后各速度时的齿轮箱垂向振动加速度的幅值有所减小;在频域上,齿轮箱各速度时的垂向振动加速度在齿轮啮合频率处的幅值大幅减小,平均减小量为65.01%。

Investigations on lubrication characteristics of high-speed electric multiple unit gearbox by oil volume adjusting device

In this paper,a numerical simulation model of the flow field in a gearbox with an oil volume adjusting device is established for the first time to study its influence on the lubrication characteristics of a high-speed electric multiple unit(EMU)gearbox.The moving particle semi-implicit(MPS)method is used to numerically simulate the internal flow field of the gearbox of the high-speed EMU under working conditions.The effects of the velocity of the high-speed EMU,the immersion depth,and the oil sump temperature on the power loss of the gears and the lubricant quantity of each bearing are studied and provide an effective tool for the quantitative evaluation of the lubrication characteristics of the gearbox.The lubrication characteristics of the gearbox under different working conditions are studied when the oil volume adjusting device is closed and opened.The results show that the oil volume adjusting device mainly changes the amount of lubricant stirred by the output gear by changing the flow rate of lubricant from the cavity pinion(Cavity P)to the cavity gear(Cavity G),and thus affects the power loss of gears and the lubricant quantity of each bearing.

市域动车组齿轮箱关键技术研究

为满足市域动车组齿轮箱的性能需求,文章分析了市域动车组齿轮箱的主要技术参数和结构特点,对齿轮设计、箱体设计、轴承选型、润滑密封等关键技术开展研究,并对润滑油路和密封结构进行合理优化。计算验证结果表明,该型齿轮箱设计满足市域动车组的使用要求。

CR-Fuxing high-speed EMU series

1Overview of the CR Fuxing high-speed EMUseries The independently developed CR(China Railways)Fuxing high-speed EMU(electric multiple unit)series by China currently comprises three speed-level product series:CR400,CR300,and CR200,as shown in Fig.1.The EMUs demonstrate adaptability to various geographical and climatic conditions,including high plateaus,extremely cold regions,strong wind and sandy environmental conditions,with a designed service life of 30 years.The 350 km/h speed level of the CR-Fuxing series primarily consists of two platforms,namely CR400AF and CR400BF,both of them are electric multiple units with distributed power.Each 8-car formation is configured with a 4M4T arrangement,divided into two traction units(Tc+M+Tp+M).

高速动车组齿轮箱异常振动试验分析

在分析齿轮箱振动特性的基础上，对其进行了振动模态试验和线路跟踪测试分析，找出齿轮箱箱体异常振动的根本原因。模态试验结果表明：齿轮箱的箱体模态最低为551Hz，其模态振型为扭转和弯曲的复合模态并以弯曲模态为主。通过线路振动测试结果可以看出，轴箱垂向振动加速度小于横向振动加速度，而齿轮箱振动正好与轴箱相反；从均方根的幅值大小来看，从轴箱到齿轮箱横向振动加速度的变化不是很大，但垂向振动加速度变化明显。齿轮箱上的垂向振动加速度均方根幅值是轴箱的2倍左右，这说明从轴箱到齿轮箱的振动传递存在放大现象。当运营速度接近300km／h时齿轮箱的振动加速度会急剧上升。通过相应的频谱分析发现齿轮箱的振动主频介于500-600Hz之间，非常接近齿轮箱的最低固有频率。这表明齿轮箱异常振动的根本原因在于轮轨上的高频激扰传递到齿轮箱上从而引起了结构共振。

高速动车齿轮箱故障诊断技术研究综述

齿轮箱是高速动车驱动系统的重要组成部分,由于长期处于高速重载的工作环境,易受到损伤和出现故障。因此,快速准确地对高速动车齿轮箱的故障进行诊断具有重要意义。从分析动车齿轮箱的结构型式和常见故障入手,阐述了国内外用于动车齿轮箱故障诊断的振动分析、噪声分析、温度场分析、油液分析及声发射等典型技术的应用现状,对这些技术作了适用性分析并提出了重点研究方向建议。分析结果表明,当前应用于高速动车齿轮箱的多种故障诊断技术均有其各自不同的优缺点和应用场合,单种诊断技术受限于其局限性,均不能较好地精确诊断出动车齿轮箱的多类故障;应用基于先进智能算法的多种技术融合,有望是今后该领域故障诊断的研究重点之一。

外部激励下齿轮箱振动分析与动应力评估

针对高速动车齿轮箱箱体应力集中问题,从轨道不平顺激励的角度对其箱体的振动特性与动应力分布进行评估。首先建立了高速动车的齿轮箱、转向架及整车的刚柔耦合动力学模型,其次利用转向架滚振实验台测量了动车齿轮箱在轨道不平顺激励下的振动加速度,其中工况选取了100km/h、200km/h及300km/h匀速运行工况。依据实验结果对动车系统的铰接类型、力元类型与参数进行了匹配性调整。最后仿真计算了齿轮箱箱体仅在轨道不平顺激励下的动应力,发现箱体整体等效应力主要集中于小齿轮端箱体处、小齿轮与大齿轮端箱体过渡联接处,其中在100km/h、200km/h和300km/h工况下,箱体平均等效应力范围依次为(2.03~2.30)MPa、(3.87~4.29)MPa、(6.81~7.25)MPa。发现轨道不平顺激励对箱体的振动特性产生一定影响,且箱体易出现应力集中现象。

高速动车组齿轮箱迷宫密封系统设计与试验验证

密封系统设计是高速动车组齿轮箱设计中的难点,良好的密封系统既要保证列车高速运行工况下对齿轮箱内部润滑油有较好的密封性能,又要防止外界风沙雨雪等杂物进入到齿轮箱内部对齿轮箱造成污染,同时还要满足使用维护方便的要求。应用迷宫密封设计原理,完成了某动车组齿轮箱密封设计,并通过了试验验证。试验结果表明,该密封设计可靠,满足双向密封及使用维护方便要求。

CRH2型动车组齿轮箱跑合试验振动数据分析与研究

介绍了振动分析的基本理论和齿轮箱的典型故障,并对CRH2型动车组转向架齿轮箱跑合试验台振动数据进行了分析。通过对不同转速下频谱特征的对比,剖析了齿轮箱的运行状态;为进一步分析和制定动车组齿轮箱跑合试验振动分析标准作了有益的探索。

基于刚柔耦合模型的动车组齿轮箱箱体振动特性研究

以国内某型动车组齿轮箱为研究对象,着重研究箱体的振动特性。首先在SolidWorks软件中建立齿轮箱整体结构的三维模型,然后利用ANSYS软件将箱体柔性化,最后在ADAMS软件中建立齿轮系统刚性且箱体柔性的刚柔耦合模型,分析箱体在内部激励下的振动特性。研究结果表明,箱体不同部位的振动特性不同,振动位移较为明显的区域在上箱体顶端和上箱体大齿轮轴承座处,振动速度较为显著的区域在小齿轮轴承座和下箱体大齿轮轴承座处,振动加速度较为突出的区域在小齿轮轴承座和上箱体观察口处。以上研究方法与结论,能够为动车组齿轮箱箱体的结构优化和健康监测提供相应参考。

高速动车组齿轮箱设计研究现状及趋势

齿轮箱是高速动车组动力转向架的核心部件,其性能直接影响运行的安全可靠性。介绍了目前国内高速动车组齿轮箱结构及安装方式。根据齿轮箱的结构,分别从齿轮、支架、箱体、润滑密封等方面描述了国内外高速动车组齿轮箱设计方法的研究现状及存在的问题。提出了后期应重点针对齿轮箱的造型设计、故障诊断与健康管理和极端环境下的产品性能等方面开展相关研究,为深入研究高速动车组齿轮箱提供了参考。

服役工况下高速动车组齿轮箱箱体振动特性分析

为探究某高速动车组齿轮箱箱体在服役工况下的振动特性,对齿轮箱开展线路跟踪服役试验,通过分析测试系统在齿轮箱箱体多路线工况下采集的数据,研究其所真实反映的齿轮箱箱体及轴箱在实际运营线路中的振动特性。结果表明:齿轮箱箱体的振动比轴箱的振动更易受到列车速度变化的影响,且箱体的振动加速度与列车运行速度变化趋势基本一致;试验动车组在镟轮后运营15万至20万公里时踏面形成23阶车轮多边形,且23阶车轮多边形的激扰主频655 Hz与齿轮箱箱体局部固有频率相近,发生共振现象。此外,列车运行过程中轮轴转频、枕跨冲击频率等调制频率也会加剧箱体振动。有关结论能为高速列车齿轮箱性能评价及优化提供参考。