V型带传动的传递功率损失 第Ⅱ部分:小带轮半径的影响(二)

采用运转的缠绕、毛边和齿形的V型带传递51,36和21mm半径带轮间的功率。分开测量该带轮间的转矩和角速度损失表明它们分别近似与I/R和I/R2成比例,同时还大于根据现有理论的预测值。带轮半径由51减小至21mm时,最大有效拉力比由21降至5。根据转矩损失的简化分析出现一无因次带变形参量(gEI/R4)1/2,已经验求得与超出根据带拉长和径向屈服预测的转矩损失和速度损失两者有关。采用厚平带和圆柱带轮的辅助试验表明它的功率损失与相同截面积的V型带意外的接近,建议这些V型带损失归因于一般原始楔入带轮槽的情况,必须研究推测带体变斜或剪切变形说明小半径带轮与损失的关系。     

V型带传动的传递功率损失第Ⅱ部分:小带轮半径的影响(一)

采用运转的缠绕、毛边和齿形的V型带传递51,36和21 mm半径带轮间的功率.分开测量该带轮间的转矩和角速度损失表明它们分别近似与I/R和I/R2成比例,同时还大于根据现有理论的预测值.带轮半径由51减小至21 mm时,最大有效拉力比由21降至5.根据转矩损失的简化分析出现一无因次带变形参量（gEI/R4）^1/2,已经验求得与超出根据带拉长和径向屈服预测的转矩损失和速度损失两者有关.采用厚平带和圆柱带轮的辅助试验表明它的功率损失与相同截面积的V型带意外的接近,建议这些V型带损失归因于一般原始楔入带轮槽的情况,必须研究推测带体变斜或剪切变形说明小半径带轮与损失的关系.     

V型带传动的传递功率损失第Ⅰ部分:V型带和带轮楔角失配的影响

AV10原始毛边的V型带分别切成由32°到42°楔角,和36°楔角的带轮在51 mm的节圆半径上啮合运转,实验表明,37°到38.5°楔角的带与槽配合最好,啮合运转的效率最高.而其他楔角的带由于不能与带轮槽较好配合的径向失配造成超速和转矩损耗的功率损失.故现有失配带的径向配合的理论模型是不适当的.本结论已经推广并开发了带弯曲变形理论,详细介绍了按照带轮半径、带的结构和带的长度,带轮槽与带啮合运转的角度切成40°,运转效率最高.     

金属带式无级变速器带轮变形损失研究

为了减少金属带式无级变速器变速机构的传动损失,分析了带轮变形损失机理,推导出带轮变形损失计算模型。基于某国产无级变速器的实际参数,引入由有限元方法建立的带轮轴向变形模型,定量分析了带轮变形所导致的楔入损失及进出口损失,获得了金属带速比、输入转矩对带轮变形损失的影响规律。分析结果表明:带轮变形损失随输入转矩的增大而增大,在最小速比和最大速比位置的损失大于中间速比位置的损失,其中楔入损失是构成带轮变形损失的主要部分;可通过提升带轮在最大工作半径处的等效轴向刚度来减小变形损失。最后通过台架试验验证了变形损失计算模型的可信性。     

金属推型V带无级变速箱损耗机理仿真部分2:带轮变形损失和总转矩损失的论证

以推型金属带为基体的无级变速箱(CVT)的动力传动效率低于有级变速箱,大家已经认识到采用CVT改进发动机负荷匹配所取得的燃料经济性的好处有被取消的趋势.本组三篇论文详细阐述了发生在作为第一级用来取得效率改进的带传动中损耗机理的研究.本第二篇文章是接上第一篇论文,其中进行了分析由于带轮和带的推块之间相对运动产生的损失.进行附加的实验研究表明在变速器的带轮上产生较大的变形,除第一篇文章讨论之外进一步推荐转矩损失模拟表明转矩损耗较小,但与带有关联的转矩损失仍较大.本研究考虑到其他研究中的新发现并改变金属V带的设计.本组中第三篇论文开发了许多模型,依据于第一篇论文中开发的力分布模型来预测变速器装置中带滑动的损失.     

金属V-带推块型CVT的研究(Ⅰ)——传递转矩和带轮推力间关系

本文在金属Ｖ－带推块型ＣＶＴ上,测出了主、从动带轮的传递转矩和推力以及峡谷带轮间的轴向力。绘出了不同速比下主,从动带轮间相对于转矩比的比线图并作相互比较。发现推力比与速比几乎和带轮转速及正常转矩下的最大可传递的转矩无关,该推力比是速比的函数,它和转矩比及推块与带轮间的摩擦系数有关,还导出了带轮推力经验平衡方程式,该式以显函数形式表示。它可以简化并可适用于电控ＣＶＴ。     

金属带式无级变速器带轮变形摩擦损失分析

金属带式无级变速器(CVT)的带轮变形会导致金属带沿着带轮锥面发生径向偏移,从而使得系统产生摩擦损失,严重影响变速机构的传动效率.以某国产CVT为研究对象,建立了带轮变形摩擦损失模型并利用ANSYS软件对金属带式无级变速器传动部分进行有限元仿真分析.分析结果表明:速比是影响带轮变形的主要因素,带轮锥面最大变形量随着工作半径减小而逐渐减小.同时,从摩擦损失模型可以看出发生在带轮工作半径上的最大变形量是影响摩擦损失的主要因素,带轮摩擦损失在传动比较大或较小时达到最大值,并且随着输入转矩的增加摩擦损失也随之而增加.     

金属推型V带无级变速箱损耗机理仿真部分3:带的滑动损失

大家已经知道,以推型金属带为基件的无级变速箱(CVTs)的传动效率低于速比间断变化的变速器,这种倾向是用CVT由于发动机/负荷匹配得到的燃油经济性的好处有被抵消的趋势.本论文组三篇论文详细地阐述了作为第一级得到的改进效率的带传动中损耗机理的研究.接上述两篇论文本文对由于带组和带的推块之间的相对运动以及带轮和带由于带轮变形的影响发生转矩损失进行模拟分析.本文还描述了附加的实验研究,测出了变速器内两带轮的切向滑动速度.推荐了附加的损耗模型,基于目前其他推荐的理论外,阐述了除论文1和论文2的讨论外的带滑动现象.通过转矩损耗和论文1和论文2中推荐的转矩一力分布的相互作用对比实验范围证实了本文进行的有关分析.本文考虑到其他研究中的新发现,改变目前金属V带的设计.     

V带传动带楔入、退出带轮轮槽摩擦损失分析

带传动中带在楔入和退出轮槽时 ,由于带与轮槽之间存在摩擦 ,会产生效率损失 ,本文对带进入和退出轮槽所产生的摩擦损失进行了详细的研究分析 ,推导了带进入和退出轮槽所产生的功率损失的计算方法 ,分析了它对带传动的效率的影响程度 ,并研究了其与轮槽角的关系。     

离散式变径带轮无级变速器设计与分析

提出一种新型面接触式摩擦传动结构的无级变速器——离散式变径带轮无级变速器。分析了离散式变径带轮传动结构的尺寸参数与传动比的关系,推导出离散式变径带轮传动临界摩擦力的计算公式,验证了离散式变径带轮理论上具有大转矩传动能力。另外,进行了基于ADAMS的转速波动性分析,并搭建离散式变径带轮无级变速器实验装置进行测试验证,结果表明,其转速波动满足大部分设备的传动要求。新型离散式变径带轮无级变速器结构紧凑、设计合理,具有很大的开发价值。     

Modeling and experimental evaluation of torque loss in turbine test rig for accurate turbine performance evaluation

The performance of a turbine is evaluated through a turbine rig test by measuring the torque or power generated from the test turbine using a dynamometer or torque sensor installed in the test rig. Highly precise assessment requires accurate measurement of the torque or power. However, an intrinsic difficulty exists such that not all power generated by the turbine is measured by the dynamometer or torque sensor. A small portion of power generated from the test turbine is dissipated between the test turbine and torque sensor as bearing and windage losses. The dissipated energy is called mechanical loss of test rig. Therefore, measuring the mechanical loss of the test rig is necessary for the accurate evaluation of the turbine performance. The present paper classifies mechanical loss into bearing, disk windage, and extra windage losses. Spin-down tests are performed in a 1-stage axial turbine test rig to evaluate each loss. The total mechanical loss amounts to 0.78% to 1.4% of energy generated at the turbine. Bearing loss is dominant. Mechanical loss is dependent on and increases with decreasing bearing temperature.     

Load speed regulation in compliant mechanical transmission systems using feedback and feedforward control actions

The problem of controlling the load speed of a mechanical transmission system consisting of a belt-pulley and gear-pair is considered. The system is modeled as two inertia (motor and load) connected by a compliant transmission. If the transmission is assumed to be rigid, then using either the motor or load speed feedback provides the same result. However, with transmission compliance, due to belts or long shafts, the stability characteristics and performance of the closed-loop system are quite different when either motor or load speed feedback is employed. We investigate motor and load speed feedback schemes by utilizing the singular perturbation method. We propose and discuss a control scheme that utilizes both motor and load speed feedback, and design an adaptive feedforward action to reject load torque disturbances. The control algorithms are implemented on an experimental platform that is typically used in roll-to-roll manufacturing and results are shown and discussed.     

聚合物齿轮泵功率特性研究

对斜齿齿轮泵的功率特性进行了理论研究和数值计算，建立了泵轴的机械摩擦扭矩、液压扭矩、流体粘性摩擦扭矩和流体碰撞损失扭矩的数学计算模型，并且对泵的输入功率进行了理论研究，分别建立了适用于牛顿流体和幂律流体的功率特性数学计算模型，通过数值计算仿真得到泵的特性曲线，为研究齿轮泵的输入特性提供了理论依据。     

Development and Validation of an Automotive Axle Power Loss Model

This study proposes a methodology to predict power losses of automotive axle units, including both load-dependent (mechanical) and load-independent (spin) loss components. This methodology combines a mechanical hypoid gear mesh power loss model, a new tapered roller bearing mechanical power loss model, a gear drag loss model, and empirical viscous bearing power loss formulae to determine the total power loss of an axle unit. The proposed methodology captures the effects of operating conditions (speed and torque and oil temperature and level), contact surface roughness amplitudes, as well as bearing preload on power loss. The model is employed to simulate published axle efficiency experiments. Direct comparisons between measured and predicted power losses are presented to demonstrate the accuracy of the proposed modeling methodology.     

液力变矩器的效率模型研究

在液力变矩器中，由于流体流动的复杂性，尚无效率的数学模型。从流体的流动损失、机械损失和泄漏损失出发，得到了系统的流动效率、机械效率和泄漏效率的数学模型，进而得到了液力变矩器的效率模型。     

The effect of torque scheduling on the performance and mechanical loads of a wind turbine

The generator torque control loop of a multi-MW wind turbine consists of three operational regions, i.e. a max Cp region, a transient region around the rated rotor speed, and a power regulation region. The performance and mechanical stress on the wind turbine structure are closely related with how the torque schedule is mechanized in the transient and above-rated regions. Using a drive train model, the closed loop dynamic characteristics for different torque schedules were analyzed. It is found that the slope of the torque for the rotor speed in the transient region is the major factor which determines the performance and mechanical loading of the wind turbine. The effect of using a variable torque instead of the fixed rated torque in the above-rated region is also analyzed.     

磁流体密封的阻力矩分析

本文分析了磁流体密封中的阻力和损耗。指出磁流体密封中存在基本粘滞损耗和附加损耗,分析了两种损耗的产生原因,特性及影响因素,提出了减小损耗的方法。     

Cutting torque and tangential cutting force coefficient identification from spindle motor current

This article presents an enhanced methodology for cutting torque prediction from the spindle motor current, readily available in modern machine tool controllers. This methodology includes the development of the spindle power model which takes into account all mechanical and electrical power losses in a spindle motor for high-speed milling. The predicted cutting torque is further used to identify tangential cutting force coefficients in order to predict accurately the cutting forces and chatter-free regions for milling process planning purposes. The developed model is compared with other studies available in the literature, and it demonstrates significant improvements in terms of the completeness and accuracy achieved. The developed model is also validated experimentally, and the obtained results show good compliance between the predicted and the measured cutting torque. The developed enhanced procedure is very appealing for industrial implementation for cutting torque/force monitoring and tangential cutting force coefficient identification.     

带轮旋压成形原理及工艺分析

通过对钣制皮带轮旋压成形过程的运动及应力应变分析 ,指出预成形槽的形状、顶压座的轴向送进速度及旋轮的径向进给速度等是带轮正确成形的主要影响因素。     

齿轮啮合过程摩擦功耗研究

A novel method for frictional power losses of a gear meshing was presented according to the basic theory of power and energy of the system. It was provided that the relative sliding of two disks existed during the disks rotating, frictional power losses will be caused by the frictional torque for each disk. Based on the above principle, the model for the friction power loss of the gears meshing was built. The frictional coefficient plays important role to the frictional power loss of gears and the time-varying coefficient was analyzed. Based on the system frictional power loss of the gears, the time-varying frictional power loss was calculated. The results indicate that the power loss in the double tooth meshing plays significantly role in the whole power losses. Finally, the results obtained from the new method were compared to the test results by Velex and it is shown that the model of frictional power loss is feasible.