Modal analysis of coupled vibration of belt drive systems

The modal method is applied to analyze coupled vibration of belt drive systems. A belt drive system is a hybrid system consisting of continuous belts modeled as strings as well as discrete pulleys and a tensioner arm. The characteristic equation of the system is derived from the governing equation. Numerical results demenstrate the effects of the transport speed and the initial tension on natural frequencies.

Tensioner Vibration and Belt Slipping Behavior Investigation for Damped Serpentine Belt Drive Systems

A nonlinear rotational motion model for n-pulley damped serpentine belt drive systems （SBDSs） was developed.The effects of the belt deflection along the contact arc of pulleys on the belt span tensions were considered.The methods for calculating the tensioner arm vibration and belt slipping on pulleys were introduced.The effects of belt damping on rotational vibration of tensioner arm and belt slipping on pulleys were studied.Numerical solutions for a 3-pulley SBDS indicate that the belt slipping at the steady states should be controlled to avoid belt slipping at transient states.The slip factors tend to decrease when the belt damping increases,and the possibility of the belt slipping can be controlled through adjusting the wrap angles of pulleys and the preload of the tensioner when the design parameters of SBDS remain constant.

Reliability and Availability Models of Belt Drive Systems Considering Failure Dependence

Conventional reliability models of belt drive systems in the failure mode of fatigue are mainly based on the static stress strength interference model and its extended models, which cannot consider dynamic factors in the operational duration and be used for further availability analysis. In this paper, time-dependent reliability models, failure rate models and availability models of belt drive systems are developed based on the system dynamic equations with the dynamic stress and the material property degradation taken into account. In the proposed models, dynamic failure dependence and imperfect maintenance are taken into consideration. Furthermore, the issue of time scale inconsistency between system failure rate and system availability is proposed and addressed in the proposed system availability models. Besides, Monte Carlo simulations are carried out to validate the established models. The results from the proposed models and those from the Monte Carlo simulations show a consistency. Furthermore, the case studies show that the failure dependence, imperfect maintenance and the time scale inconsistency have significant influences on system availability. The independence assumption about the belt drive systems results in underestimations of both reliability and availability. Moreover, the neglect of the time scale inconsistency causes the underestimate of the system availability. Meanwhile, these influences show obvious time-dependent characteristics.

Modeling of large scale solar cell handling robot with belt-driven flexible arms

To increase the competition of the solar energy collection system, the size of the solar panel module during the manufacturing process is being increased continuously. As the size of the solar panel increases, the size of the robot to handle the panel increased also. The change in scale of the robot inevitably results ill the amplification of the adverse effect of tile flexure. The main source of the flexure in the large scale solar cell panel handling system is the long and thin fork fingers of the [land and the solar cell panel. In addition, tile belt-driven actuator system used by most of the large scale panel handling robot is another significant source of the vibration. In this paper, the flexible multi body dynamic model of a large scale solar cell panel handling robot, which is being designed and constructed with the help of Kyung Hee University, is developed. The belt-driven system in the robot is also modeled as flexible system and included ill the robot to represent the actual vibration characteristics of the actuator system. C 2013 The Chinese Society of Theoretical and Applied Mechanics. [doi： 10.1063/2.1301310]

LOAD DISTRIBUTION ON DRUMS OF DOUBLE DRIVE BELT CONVEYOR

The double drum drive is widely used on the mine belt conveyor, which are divided the rigid connected double drums and separately driving double drums according to connected method of two drums. Because of the change of real work condition, the load distribution is changed on the two drive drums, which may produce a slippage between a drum and belt. Slippage may intensify the wear of the drum, and sometimes causing the fire of the belt. This restricts the development toward narrow belt, high velocity and large power of belt conveyor. In this paper, the factors affecting the load distribution of two drums of double drum belt conveyor are systematically analyzed and some computing formulas derived, by these formulas, the actual lcad distribution on the two drums of rigid connected or separately driving belt conveyor can be separately calculated.These formulas also can be as the theory base for adjusting the driving force of two drums.

Optimal Driving of Large Belt Conveyor with Multi-roller Variable-Frequency Drive

in this paper, an electromechanically coupled mathematic model of multi-roller driving system for belt conveyor is set up, and the computing equations for dynamic displacement and dynamic tension of the conveyor are also formulated when the hoister is used for straining. Based on the belt conveyor of main inclined shaft in Chengzhuang coal mine, the driving torque, driving power and starting-speed characteristic of each electric motor are studied and measured when multi-roller variable-frequency drive (power distribution 2∶1) is used. The optimal control and the optimal starting-acceleration of the multi-roller variable-frequency drive are determined by a large number of industrial experiments and theoretical calculations.

激光旁轴送气结构设计与分析

目的通过了解激光增材技术,设计一种送丝送气一体化机构,并建立相应模型。方法通过对不同送丝送气机构进行对比分析,设计出3种方案,并通过流体模型分析保护气体氩气的流动情况,最终得出最合理的安装位置。第1种方案是采用送丝机构与送气机构对冲的两轴送丝送气设计方案;第2种方案是采用送丝机构与送气机构同路的设计方案;第3种方案是选择两路送气机构与送丝机成夹角对冲的设计方案。结果在第1种方案中,送丝机构与送气机构的对冲会导致气流紊乱,产生气体流动扩散现象,可以明显看到有一个保护气体比较密集的区域。在第2种方案中,当送丝机构与送气机构同路时,在工作过程中有可能出现防氧化效果不够好的情况。在第3种方案中,两路送气机构与送丝机成夹角对冲可以有效控制氩气的流动,提高氩气的利用率,在这里进行丝材的激光熔覆将会起到最大的防氧化保护作用。结论通过对不同送丝送气机构进行对比分析,最终确定三路送气方案的保护效果最佳。

地理探测器方法下长江经济带(江苏段)土地城镇化时空演变及驱动因子分析

定量分析土地城镇化时空演变驱动力可为城市可持续发展提供科学依据。本文将对地观测数据与人口、经济数据相结合,以长江经济带(江苏段)沿江8市为例,基于2000—2020年5期Landsat影像、夜间灯光影像、年末人口总数和GDP,采用GeDetector对其近20年间空间、人口及经济维度的演化及多尺度分化的进程进行探讨,分析土地城镇化时空演变规律及驱动因子。研究结果表明:(1)城镇化过程直接驱动地表类型的变化,且人口数量和GDP总量能够作为城镇化过程强度的定量指标;(2)夜间灯光(NTL)数据耦合人口或经济统计数据能够较好解释区域城镇化过程中的时空差异;(3)长江经济带(江苏段)沿江8市城镇化过程经历了由数量向质量的转变。研究结果为引导城镇建设用地合理配置提供科学依据,为城市可持续发展提供决策参考。

发动机前端附件带传动系统动态特性研究

考虑各附件轮时变负载、时变激励、多楔带纵向刚度、径向刚度和弯曲刚度的作用,利用Simdrive软件建立了内层和外层发动机前端附件带传动系统动力学分析模型;对系统的静态特性进行评估,采用Galerkin法进行系统空间离散,利用隐式多步法求解加速工况下系统的动态特性,得出附件轮转速波动、张力波动、带-轮间滑移特性的影响因素;根据分析结果,提出了适当增加初始张力、曲轴轮包角和惰轮2处添加自动张紧器的改进方案。对比分析得知,添加自动张紧器时,发动机前端附件带传动系统的动态特性得到了有效改善。

产业结构高级化对区域用水强度时空差异的驱动效应

从时空维度将区域用水强度的影响效应分解为工业化效应、产业结构高级化效应、第三产业节水技术效应、生活用水承载力效应以及城镇人口用水规模效应,构造区域用水强度时空差异的LMDI分解拓展模型,以长江经济带为例,深入探究产业结构高级化对用水强度时空差异的驱动渠道以及内在影响机制。结果表明,产业结构高级化是2000—2020年抑制长江经济带用水强度增加的一个重要因素,但其抑制作用自2012年起逐年减弱,转为促进用水强度的增长,2020年又转为抑制作用。自2011年起,抑制或促进各省市相比于上海市用水强度增加的驱动力皆存在弱化趋势。服务化态势下的各省市产业结构调整可抑制其相比于上海市用水强度的增加,安徽省、江西省、湖南省、江苏省和四川省要加强水资源在产业间(尤其是一二产业间)的合理化配置并优化产业内部(尤其是第二产业)的耗水结构,贵州省、湖南省、云南省和湖北省服务化水平较低,仍需进一步发展第三产业。

经济型数控车床动力系统部分设计与研究

数控机床及由数控机床组成的柔性化制造系统是改造传统机械加工装备产业、构建数字化企业的重要基础。随着先进制造业的发展,对数控机床的设计,特别是经济型数控机床的设计已经成为迫切而艰巨的任务。本文通过对同类型车床的分析,提出了?360经济型数控车床动力系统部分的技术方案,提出一种新的方案,其传动过程更稳定,结构也相对比较简单。

DTⅡ(A)型带式运输机传动滚筒优化设计和分析

为进一步探究带式输送机传动滚筒可能的优化路径,以某煤矿企业常用的DTⅡ(A)型带式输送机为研究对象,对该带式输送机中的传动滚筒结构进行三维建模和有限元分析,结合应力与应变分布情况提出该传动滚筒的优化策略.在此基础上,结合ANSYS有限元分析软件中自带的优化功能,通过输入参数、生成优化文件和自动迭代计算等步骤,对该传动滚筒结构参数进行优化.优化结果显示,优化后的传动滚筒在应力和应变均未对结构产生过多影响的前提下,有效实现了减重目标,从而兼顾了运行性能和成本,表明此次研究发挥了一定的作用.

上运带式输送机轴功率计算方法的探讨

传动滚筒轴功率是带式输送机的重要设计参数。以中部张紧式带式输送机为研究对象,探讨其传动滚筒轴功率计算的阻力计算法、张力计算法和简易计算法三种方法。通过应用三种方法对工程算例的结果比较分析,验证了三种计算方法带式输送机轴功率的特点和适用性,为设计者对输送机的设备选型提供了参考。

矿用带式输送机传动滚筒的轻量化设计及其应用研究

以DTL160/330/3×1600型带式输送机为研究对象,在对输送机以及传动滚筒进行概述的基础上,利用UG和ANSYS软件建立了滚筒的有限元模型并分析其应力和变形情况。发现最大应力和变形分别为133.64 MPa和3.8237 mm,强度和刚度上均存在明显冗余问题。对支撑环、筒体和轮辐进行轻量化设计,去除了部分区域的体积,使得滚筒整体质量降低了11.18%。对新的滚筒结构进行有限元分析,发现最大应力和变形均有所增加,但是安全系数最小为1.79,在煤矿机械标准要求范围内,可以满足实际使用要求。将新的滚筒结构应用到带式输送机中,经过实践应用,达到了预期效果,产生了良好的经济效益。

某车型BSG轮系皮带脱落的分析及改善优化

随着汽车行业的不断创新发展,发动机新技术不断的应用、各种测油耗APP的使用,消费者对乘用车的油耗及加速性能都极为关注,也开始对车辆的舒适性、整体NVH性能、油耗要求不断提高。新技术BSG系统,替代传统的发电机及起动机,有启动、助力、能量回收、发电等4个功能,从而提高车辆的动力性、经济性及NVH性能。由于BSG系统工况复杂,并且采用楔型皮带进行驱动,BSG电机在工况切换时会使得皮带的松紧边进行切换,通常会使用双向BSG张紧器进行张紧。针对某车型BSG轮系皮带脱落问题,对皮带脱落的产生机理及影响因素进行分析,通过对轮系系统的优化,结合耐久试验,研究了BSG轮系驱动皮带在光轮两端的长短调整对轮系的影响及改善效果。最终通过优化轮系布局解决了皮带脱落问题。

带式输送机智能化联合驱动控制系统的应用研究

针对多电机驱动带式输送机系统在运行过程中所存在的重载启动稳定性差、功率平衡性差、张紧装置反应速度慢的问题,提出了一种新的带式输送机智能调速控制系统。该系统采用了闭环矢量控制、多电机柔性协调控制、多条件闭环张紧调节控制等提高了输送机系统运行的稳定性。根据实际应用表明,该系统能够保证输送机在不同负载情况下的启动平稳性、消除运行中的功率不平衡性,将张紧装置的响应时间缩短73.1%。

带式输送机驱动张紧组合装置设计

为满足较小巷道空间内煤流的运输需求,在常规设计方案上作出改进,设计研究一种将驱动部和张紧部组合为一体的装置,优化输送机结构,降低设备宽度,有效利用巷道已有空间,避免二次开辟驱动硐室,减少巷道改造成本和工作量.

机车空压机皮带张紧程度检测方案设计

铁路机车普遍采用空气制动方式,空气制动的风源来自空压机,空压机与动力源之间采用带传动。带传动设计中皮带松紧程度是必须考虑的问题,皮带安装过松或过紧均会产生不良影响。皮带安装过松会出现打滑现象,影响传动效果;皮带安装过紧会增加磨损,减少皮带使用寿命。带传动设计时对带传动松紧程度的判断是通过皮带受力与挠度大小来判断的,通过计算可以得出皮带应该施加力的大小与挠度。但是,在皮带实际安装过程中,由于无法准确测量皮带的受力和挠度,皮带松紧程度通常通过用手按压来判断,导致空压机皮带松紧程度不合理。为了确保空压机皮带安装张紧程度适中,文章设计了一种皮带张紧程度检测方案,该方案通过分别检测皮带安装的压力与挠度,进而判断皮带松紧程度是否符合安装要求。该方案操作方便、成本低廉,可实现空压机皮带张紧程度检测功能。