基于虚拟样机的往复牵引传动试验机设计与仿真研究

为了解决目前国内大部分试验机不能研究非稳态条件下油膜牵引传动特性的问题,设计了一台可用于研究非稳态条件下油膜牵引传动特性的试验机。利用Pro/E软件建立了往复牵引传动试验机虚拟样机模型,并对其运动学特性和动态特性进行了研究,得到了相应参数的特性曲线。研究结果验证了设计结果的正确性,得到了往复牵引传动的各项运动特性参数和运动轨迹随时间的变化规律。为后续牵引传动试验机非稳态条件下动态特性的研究提供了一定的参考依据。     

非稳态下牵引传动试验机的特性研究

对非稳态下牵引传动试验机的牵引传动特性进行了研究,并利用PRO/E、MATLAB等计算机软件对它进行了动态静力分析;同时利用质量动代换平衡的结果对机构平衡进行研究,进而预测出实际摆动力完全平衡后的动态特性.     

牵引传动设计方法的研究及实践

牵引传动是一种性能优越的新型传动,由于目前其传动的机理尚未被完全了解,因此还没有十分成熟的牵引传动设计准则及设计方法.本文针对此特点对牵引传动装置的设计方法进行了研究,并通过实验对其进行了验证.     

斜楔型牵引传动研究与应用

在常规牵引传动的基础上提出一种依赖反复微小振动进行动力传递的斜楔型牵引传动。首先通过在混合润滑状态下楔形振动片形成油膜的实验,得出在接触区施以微小振动更易形成油膜的结论;又通过斜楔型牵引传动实验,对牵引传动和摩擦传动的输出情况进行对比,以及耐久性试验,结果表明,斜楔型牵引传动相对于摩擦传动具有磨损小的优点。斜楔型牵引传动可广泛应用于驻波型超声马达等领域。     

行星牵引传动在冷却塔中的应用

光滑圆柱体组成的行星牵引传动具所有超低噪音、超低振动的优良特性，非常适合对噪音要求较高的场所。本文研究了行星牵引传动的原理，实现牵引传动的技术关键及加载机构的设计。给出了一种应用牵引传动原理设计低噪音冷却塔行星牵引传动减速器的依据和要点。     

振子驱动型牵引传动研究

在常规牵引传动和往复牵引传动的基础提出了一种依赖反复微小振动进行动力传动的振子型牵引传动。先通过振子振动形成油膜实验得出在接触区施以微小振动更易形成油膜的结论,又通过圆周运动型牵引传动实验得出了其相对于摩擦传动磨损小的优点。利用微小振动形成润滑油膜的方法引起的磨损小,可广泛应用于光学聚焦等精密运动领域。     

氧化锆在往复牵引传动中的耐磨性研究

对氧化锆的机械性能进行了详细分析,尝试将工程陶瓷氧化锆、氮化硅应用于往复牵引传动实验,并与钢材进行了对比.实验对往复牵引传动的跟踪频率响应进行了测试,验证了极限频率公式,并对1×106次往复运动后平板试件表面的损伤情况进行了研究.     

定速比牵引传动——高速传动的新选择

本文总结了用于高速、超高速场合的定速比牵引传动的研究结果，分析了高速牵引传动的特点和机构设计方法，提出了两种比较完善的行星牵引机构，对机构的设计和实验研究表明，定速比牵引机构完全能够胜任高速、超高速传动。     

汽车自动传动液电性能研究

简要介绍了新能源汽车的发展趋势及对汽车自动传动液用油情况的影响,对自动传动液电性能进行详细分析,通过试验研究了不同基础油、添加剂以及氧化程度与电导率的关系。结果表明,自动传动液中基础油和添加剂的组成对油品电导率会产生一定的影响,并且油品的电导率会随着氧化老化的程度不断增加。     

内燃机车电传动控制系统的应用研究

针对某型内燃机车的电传动控制系统的结构及应用情况进行详细分析,阐述内燃机车电传动系统的工作原理及特性,分析机车电传动控制系统结构及工作原理,对电传动控制作用下机车的牵引制动特性进行了模拟验证,为后续提升电传动控制系统效率以及提高运行经济性和使用寿命奠定基础。     

Experimental and computational investigation of the traction coefficient of a ball traction drive device

Traction drive is a new kind of drive manner in which the power is transmitted by a thin oil film between transmission elements. This paper describes a ball traction drive device. The quasi-dynamics analysis was carried out for the transmission components of the ball traction drive device. The traction coefficients of oils Ub2 and HH-20 were calculated respectively with different rheological models. The elastohydrodynamic lubrication (EHL) film thickness and the traction coefficient between traction drive elements were measured. The results of the calculations are consistent with experiments.     

牵引传动中乏油问题的研究

从弹流润滑到干摩擦状态将润滑条件分为 8个阶段对润滑油油量对牵引传动的影响进行了研究 ,试验中采用Daphne70 74牵引油。在低压情况下 ,牵引曲线上升斜率随着牵引油数量的减少而增大 ,并且在高压情况下其值接近于干摩擦状态下的值。在低压情况下 ,最大牵引系数也随着牵引油数量的减少而增大 ,并且在高压情况下其值接近于干摩擦状态下的值。即使在乏油的情况下 (拧干油布润滑 ) ,也能满足牵引传动的要求。     

粘性牵引传动--行星滚子变速器

牵引传动最早开始用于汽车工业,用它有助于解决把汽车发动机动力传递到汽车后轮.现代牵引传动是利用金属滚动体之间的粘性液体油膜把动力源的动力作有效传递.该金属滚动体可以是锥形体、圆柱形、圆盘和环节.因此所谓牵引传动必须包含三个元件:即(1)输入滚动体(2)粘性牵引液(3)输出滚动体.行星滚子牵引传动采用行星环和滚子,最早由Walter Chery为农用设备变速传动开发设计的.本文将对这种传动的几何字、运动学和力学等传动机理作比较详细的分析.     

弹性圈高速行星牵引传动机构

在总结浙大化机所超高速传动机构的设计与应用的基础上，提出了一种新的弹性圈高速行星牵引传动机构。该机构利用计算机控制高压油路系统，可任意调节与中空滚子接触处的弹性圈的变形量，以确保任意转速下传动机构的传动能力。利用有限元方法分析弹性圈的有效变形及应力的大小与分布状况，证明此机构完全能达到设计要求，能够胜任高速、超高速机械运动。     

Increase of Traction Coefficient due to Surface Microtexture

Increasing the traction coefficient of a traction drive system is a key factor in obtaining a smaller, lighter unit and also greater torque capacity. This study focused on the microtexture of the rolling elements, and effect of microtexture was examined with the aim of improving the traction coefficient in the viscous region. Three textures—dimple, transverse, and longitudinal—were examined using a 4-roller tester that enabled tests to be conducted under high pressure and high rolling speed. As a result, it was found that the longitudinal surface texture is the best for improving the traction coefficient. The results obtained with EHL analysis showed that only the surface texture with longitudinal grooves increased the traction coefficient, just as in the tests conducted with the 4-roller tester. The longitudinal surface texture was optimized using the 4-roller tester. The test results made it clear that the groove depth, groove pitch, and also the radius of curvature of the convex portion of the rolling elements are important parameters of the longitudinal grooves for improving the traction coefficient while assuring high durability at the same time. An attempt was then made to increase the traction coefficient of an actual CVT variator by applying the optimized longitudinally grooved microtexture to the traction surfaces. The test results show that the traction coefficient can be increased without sacrificing durability by optimizing the surface microtexture.     

牵引传动试验方法的归纳和对比研究

介绍了牵引传动两种以往常见的试验方法:四球机法和双圆盘法,并在此基础上运用往复牵引传动试验机进行了滚盘式试验.通过归纳和分析,得出了的结论有利于今后牵引传动研究的补充和完善.     

PERFORMANCE SIMULATION OF VEHICLES EQUIPPED WITH TRACTION DRIVE CVTS

0 INTRODUCTIONVehicles equipped with continuously variable transmission(CVT) have the potential of better fuel economy than vehicleswith conventional stepped ratio transmissions. Although the mar-ket penetration of CVT vehicles today is still insignifican…     

Effect of EHL Contact Conditions on the Behavior of Traction Fluids

New infinitely variable transmission (IVT) systems are under development for the automotive industry as a means to achieving significant fuel economy benefits. These systems rely on the lubricating fluid to transmit the drive train loads across the interface of the transmission components. This requires the development of new fluids that exhibit high traction properties under elastohydrodynamic lubrication (EHL) conditions. However, it has been reported recently that the traction performance of some fluids can reduce dramatically as temperature is reduced. This may place severe operational limits on IVT systems and suggests that the low-temperature traction properties of fluids for these systems should be studied in order to understand the mechanism for the observed reduction in traction.

The work reported here is an experimental study aimed at identifying whether low temperature traction reduction is related to a fundamental change in rheological behavior specific to the fluids tested or to more generic changes in the EHL contact conditions. A series of model experiments were performed using a mini traction machine (MTM) on three high-viscosity polybutene samples. The results have been mapped against previously reported non-dimensional parameters used to identify different EHL regimes. The results show that dramatic reductions in traction occur when the contact transitions from the rigid piezo-viscous (RP) toward the rigid iso-viscous (RI) region. Similar results were also found for two other high-viscosity fluids of different molecular structure and lower traction properties. The results support the hypothesis that the reduction in traction observed at low temperature is due to a change in EHL contact conditions rather than being solely due to a change in the rheological performance of the test fluids.     

Bulk Modulus of Lubricating Oils as Predominant Factor Affecting Tractional Behavior in High-Pressure Elastohydrodynamic Contacts

The phase diagrams corresponding to transition from liquid to viscoelastic solid and that from viscoelastic solid to elastic-plastic solid of Santotrac100 (SN100), mineral oil, synthetic naphthenic oil, polybutene, and tetradecane were first made up by high-pressure density measurements and others. The bulk modulus of lubricating oils under a quasi-static condition was evaluated using a phase diagram. The results indicated that the bulk modulus of lubricating oils is closely related to the oil molecular packing parameter T _VE ?T (where T _VE is the viscoelastic solid transition temperature at pressure p, and T is the oil temperature). The constant values of the bulk modulus in the elastic-plastic range are different depending on the molecular structures of the oils. It has also been shown that SN100, mineral oil, synthetic naphthenic oil, and polybutene converted to amorphous solids at high pressures and tetradecane converted to molecular crystal. Next, the elastohydrodynamic lubrication tractions were measured by a ball-on-disk machine. The results indicated that the maximum traction coefficient is closely related to T _VE ?T. As a result, the importance of the bulk modulus as a predominant factor for traction characteristics of lubricating oil was pointed out.