一种20kW行车自发电系统轮系及安装设计

传动轮系及发电机安装设计一直是自发电系统设计难点,本文结合工程实践,介绍了一种20kW行车自发电系统的轮系及支架设计,利用SIMDRIVESD软件计算验证轮系布局合理,轮系设计符合康明斯原车标准要求,通过CAT软件模态分析和样机验证测试,设计的发电机安装支架耐久可靠,满足使用要求.     

TJ376QE发动机多楔带轮系的开发

结合TJ376QE发动机前端轮系的开发，着重介绍了多楔带的结构及特点。对发动机多楔带轮系的设计问题进行了探讨．提出了在设计过程中应重点考虑的问题。经过300h发动机台架强化试验证明，TJ376QE发动机前端轮系的开发，其性能指标满足设计要求，通过了耐久可靠性的考核。     

CA488型发动机多楔带轮系的开发

结合ＣＡ４８８型发动机前端轮系设计的实际工作，着重介绍了多楔带设计的基本原则，并对设计中遇到的一些问题进行了探讨。４８０ｈ台架强化试验结果表明，ＣＡ４８８型发动机采用多楔带轮系后，其性能指标与采用三角带轮系时持平，且噪声（近场）略有降低。     

CA6110系列发动机前端多楔带附件传动系统设计与开发

结合CA6110系列发动机前端多楔带附件传动系统的设计与开发工作,介绍了多楔带传动系统的设计程序,即设计功率、带速和传动比、带的有效长度和包角、带的张紧及楔数的确定;介绍了CA6110发动机原轮系布置与参数,多楔带布置方案,多楔带的校核,多楔带轮系的共面要求及轮系台架试验结果。     

工程机械传动机构行星轮系的建模与仿真

进行工程机械车辆传动机构中行星轮系基于结构与机构设计以及运动仿真的研究。运用Pro/Engineer的实体建模、虚拟装配和机构仿真功能,对齿轮进行了参数化设计,与相关零件虚拟装配形成了行星轮系;并对轮系进行了运动仿真,有效提高了产品的设计、开发速度,可降低研制费用,为工程机械车辆零部件的CAD、各种技术分析和无纸自动化制造奠定基础。     

D20发动机多楔带的研究

结合D20发动机前端轮系的设计与开发工作,介绍D20发动机前端轮系的布置与参数,多楔带的布置方案,多楔带校核等相关设计内容,并对设计中出现的问题进行了讨论。经过450h发动机台架强化实验表明,D20发动机性能指标满足设计要求。     

发动机附件皮带传动系统设计

汽车发动机附件皮带传动系统的工作条件,与一般机械用轮系的使用工况有较大区别,因此不应按传统的机械带传动方式进行设计。根据汽车发动机附件皮带传动系统易出现的问题,提出了其设计的基本要求。对轮系张紧力等问题进行了分析计算,并给出了CA488型发动机轮系的计算结果。     

车用硬齿行星轮系各轮齿数的确定方法

车用行星轮系内中心轮齿数Z_1一旦被选定后,则其他各轮齿数皆可按照配齿公式一一确定。合理选择Z_1,是车用行星轮系设计计算成功的关键之一。本文提出以一组简单公式作为选择Z_1的依据。具体的计算及设计表明,以此公式为依据选择Z_1,可使车用硬齿行星轮系齿数确定方法进一步趋于合理。     

微型汽车发动机轮系仿真设计及其应用研究

简述了轮系仿真理论及设计方法.利用多体动力学仿真软件针对某款微型汽车车发动机轮系进行了建模和仿真.仿真结果表明,其曲轴带轮最高滑移率超过了7％,这样可能会引起皮带的过度磨损和噪声过大.在空调压缩动力转向泵系统增加一手动张紧轮对轮系进行了优化设计.结果表明,所设计的空调压缩动力转向泵系统皮带张力范围在250～780 N之间,各带轮滑移率均不超过3％,满足设计要求.     

大功率柴油发动机前端轮系自动张紧机构研究

针对大功率柴油发动机前端轮系自动张紧机构,分析了其在系统中的功能、设计指标、试验要求等,并以此开展了自动张紧机构涡簧关键件的设计,通过有限元分析计算、台架可靠性摸底试验和实际装机可靠性试验测试,自动张紧机构的各项指标满足大功率柴油发动机前端轮系设计要求,达到了设计目标。通过本次研究,形成的设计和实验方法为后期类似产品开发提供了依据。     

车轮螺母止推垫圈热挤压工艺试验及模具设计

车轮螺母止推垫圈热挤压工艺试验,关键是如何设计模具解决热挤压连皮超薄的问题     

Stochastic analysis of dynamic interaction between train and railway turnout

The performance of a railway turnout (switch and crossing) is influenced by a large number of input parameters of the complex train–turnout system. To reach a robust design that performs well for different traffic situations, random distributions (scatter) of these inputs need to be accounted for in the design process. Stochastic analysis methods are integrated with a simulation model of the dynamic interaction between train and turnout. For a given nominal layout of the turnout, using design of experiments methodology and a two-level fractional factorial screening design, four parameters (axle load, wheel–rail friction coefficient, and wheel and rail profiles) are identified to be the most significant. These parameters are further investigated using a three-level full factorial design and stochastic analysis. The random distributions of transverse wheel profile and set of transverse rail profiles along the switch panel are accounted for by the Karhunen–Loève expansion technique. The influence of the random distributions of the input parameters on the statistical outputs of wheel–rail contact forces, wear and rolling contact fatigue is assessed using Latin hypercube sampling to generate a number of stochastic load realizations.     

Simulation of dynamic interaction between train and railway turnout

Dynamic train–track interaction is more complex in railway turnouts (switches and crossings) than that in ordinary tangent or curved tracks. Multiple contacts between wheel and rail are common, and severe impact loads with broad frequency contents are induced, when nominal wheel–rail contact conditions are disturbed because of the continuous variation in rail profiles and the discontinuities in the crossing panel. The absence of transition curves at the entry and exit of the turnout, and the cant deficiency, leads to large wheel–rail contact forces and passenger discomfort when the train is switching into the turnout track. Two alternative multibody system (MBS) models of dynamic interaction between train and a standard turnout design are developed. The first model is derived using a commercial MBS software. The second model is based on a multibody dynamics formulation, which may account for the structural flexibility of train and track components (based on finite element models and coordinate reduction methods). The variation in rail profile is accounted for by sampling the cross-section of each rail at several positions along the turnout. Contact between the back of the wheel flange and the check rail, when the wheelset is steered through the crossing, is considered. Good agreement in results from the two models is observed when the track model is taken as rigid.     

On the overriding issue of train front end collision in rail vehicle dynamics

A three-dimensional dynamic model of crashed vehicles coupled with moving tracks is developed to research the dynamic behaviour of the train front end collision on tangent tracks. The three-dimensional dynamic model consists of a crashed vehicle model, moving track models, a simple wheel–rail contact model, a velocity-based coupler model and the model of energy absorption and anti-climbing devices. The vector method dealing with the nonlinear wheel–rail geometry is put forward in the paper. The developed model is applicable in the scope that central collisions occur on tangent tracks at low speeds. The examples of the vehicle impacting with a rigid wall and the train front end collision are carried out to obtain the dynamic responses of vehicles. The overriding issue is studied on the basis of the wheel rise in train collisions. The results show that the second bogie of the first colliding vehicle possesses the maximal wheel rise. The wheel rise increases with the increase of vehicles. However, the number of vehicles has tiny influence on the overriding in train collisions at low speeds. On the contrary, the impact speed has significant influence on the overriding in train collisions. The wheel rise increases rapidly if the impact speed is close to the critical speed of overriding. The large wheel rise is principally generated by the great coupler force related to the rigid impact in the axial direction.     

High-speed trains subject to abrupt braking

The dynamic response of high-speed train subject to braking is investigated using the moving element method. Possible sliding of wheels over the rails is accounted for. The train is modelled as a 15-DOF system comprising of a car body, two bogies and four wheels interconnected by spring-damping units. The rail is modelled as a Euler–Bernoulli beam resting on a two-parameter elastic damped foundation. The interaction between the moving train and track-foundation is accounted for through the normal and tangential wheel–rail contact forces. The effects of braking torque, wheel–rail contact condition, initial train speed and severity of railhead roughness on the dynamic response of the high-speed train are investigated. For a given initial train speed and track irregularity, the study revealed that there is an optimal braking torque that would result in the smallest braking distance with no occurrence of wheel sliding, representing a good compromise between train instability and safety.     

Energy Dissipation Due to Vehicle/Track Interaction

The effects of track irregularities and wheel profile on the amount of energy dissipated in railroad freight vehicles is examined. A nonlinear computational model is used to determine the average dissipation in the vehicle suspension and the wheel/rail contact patches. This dissipation is a component of the total resistance force acting on the vehicle. Parametric results are presented showing the effects of track geometry, wheel profile, suspension design, and hunting on train resistance. Track geometry studies consider the effects of track quality and curving. The AAR 1:20 wheel profile and the Heumann wheel profile are compared under various operating conditions. Compared with the Heumann profile, the AAR 1:20 profile is shown to have lower average resistance on good quality tangent track, but higher average resistance in steady curves. A trade-off exists between the two profiles when dynamic curve entry is considered.     

Energy Dissipation Due to Vehicle/Track Interaction

SUMMARY

The effects of track irregularities and wheel profile on the amount of energy dissipated in railroad freight vehicles is examined. A nonlinear computational model is used to determine the average dissipation in the vehicle suspension and the wheel/rail contact patches. This dissipation is a component of the total resistance force acting on the vehicle. Parametric results are presented showing the effects of track geometry, wheel profile, suspension design, and hunting on train resistance. Track geometry studies consider the effects of track quality and curving. The AAR 1:20 wheel profile and the Heumann wheel profile are compared under various operating conditions. Compared with the Heumann profile, the AAR 1:20 profile is shown to have lower average resistance on good quality tangent track, but higher average resistance in steady curves. A trade-off exists between the two profiles when dynamic curve entry is considered.     

Out-of-round railway wheels—a study of wheel polygonalization through simulation of three-dimensional wheel–rail interaction and wear

The objective of this study is to develop a tool for investigation of wheel tread polygonalization with radial irregularities including 1 to 20 wavelengths around the circumference of the wheel. Therefore, an existing multibody system model for simulation of general three-dimensional train–track interaction (accounting for frequencies up to several kHz) is extended with rolling contact mechanics according to FASTSIM. Furthermore, the model is also modified to allow for general wheel–rail profiles. The numerical model uses the concept of an iteration scheme including simulation of dynamic train–track interaction in the time domain coupled with a long-term wear model. A demonstration example including a bogie of a subway train travelling on a straight track is presented. In the example, an initial wheel out-of-roundness (OOR) is applied to the wheels. This irregularity is based on an amplitude spectrum derived from measurements on new wheels. Simulation results show that the most important wavelength-fixing mechanisms of the wheel OOR are (i) the vertical resonance of the coupled train–track system at approximately 40 Hz (the P2 resonance) and (ii) the frequency region including the lowest vertical track antiresonance at 165 Hz, where the dynamic track stiffness is high. Only a straight track is studied, but the model allows for asymmetric train motion on such a track.     

Establishment and verification of three-dimensional dynamic model for heavy-haul train–track coupled system

For the long heavy-haul train, the basic principles of the inter-vehicle interaction and train–track dynamic interaction are analysed firstly. Based on the theories of train longitudinal dynamics and vehicle–track coupled dynamics, a three-dimensional (3-D) dynamic model of the heavy-haul train–track coupled system is established through a modularised method. Specifically, this model includes the subsystems such as the train control, the vehicle, the wheel–rail relation and the line geometries. And for the calculation of the wheel–rail interaction force under the driving or braking conditions, the large creep phenomenon that may occur within the wheel–rail contact patch is considered. For the coupler and draft gear system, the coupler forces in three directions and the coupler lateral tilt angles in curves are calculated. Then, according to the characteristics of the long heavy-haul train, an efficient solving method is developed to improve the computational efficiency for such a large system. Some basic principles which should be followed in order to meet the requirement of calculation accuracy are determined. Finally, the 3-D train–track coupled model is verified by comparing the calculated results with the running test results. It is indicated that the proposed dynamic model could simulate the dynamic performance of the heavy-haul train well.