圆筒式磁流变液离合器设计的理论研究

理论研究了一种圆筒式磁流变液离合器的结构设计.基于Bingham模型描述了磁流变液的本构方程,分析了磁流变液离合器的工作原理;建立了圆筒式磁流变液离合器传递转矩与输出转速的计算模型,并导出了其设计计算公式;利用导出的设计计算公式,选用两种磁流变液材料,设计计算了两种圆筒式磁流变液车用风扇离合器的结构参数.理论研究表明,磁流变液离合器的传递转矩和输出转速都可通过改变磁流变液工作间隙中的磁场强度加以调控;所选择的磁流变液的性能对离合器的结构参数起决定性作用.     

圆盘式磁流变离合器的设计计算

介绍了圆盘式磁流变离合器的基本结构,对与圆盘式磁流变离合器设计相关的材料选择、磁路、磁流变液最佳工作区、绕线线径、绕线匝数、功耗等进行了较深入分析,提出了一套设计计算方法.     

汽车磁流变液离合器的设计

为解决当前汽车自动变速器中多片摩擦式离合器存在的缺陷,提出并设计一种新型的汽车磁流变液离合器。介绍磁流变液离合器的工作原理;设计离合器的机械组合结构,详细说明档位结构和散热结构的设计;设计磁路结构,并利用ANSYS有限元分析软件对磁路进行优化。设计的磁流变液离合器可以避免因摩擦片间的滑磨带来的故障及功率损耗,使驱动系统更安全节能;磁流变液在固态和液态之间的毫秒级可逆转化,使得离合器响应速度更快,提高了汽车的变速响应性能。     

磁流变离合器的设计与分析

介绍磁流变离合器的工作原理 ,分析了磁流变离合器设计的几何参数 ,设计中应注意的技术问题。     

圆盘型磁流变离合器的设计与分析

磁流变液是一种新型智能材料，其屈服强度在外加磁场作用下可以在毫秒量级内发生变化，利用磁流变液剪切应力可以进行动力的传递。本文应用Bingham模型来描述磁流变液的本构方程，在理论上分析了盘式磁流变液离合器的工作机理，导出了设计计算公式，并探讨了离合器设计中应注意的若干技术问题，为盘式磁流变离合器的设计奠定了理论基础。     

一种多片式磁流变液离合器

提出一种多片式磁流变液离合器 ,阐述其结构组成和工作原理 ,给出离合器在脱离状态、接合过程和接合状态的力矩计算方法 ,指出其用作传动装置和控制执行件的结构特征     

多盘式磁流变离合器磁路设计与仿真

磁流变离合器是通过磁流变液的剪切应力进行传递转矩的器件。对多盘式磁流变离合器进行磁路的设计,首先应用磁路欧姆定律,结合考虑不产生磁路磁饱和效应,初步确定磁路结构参数并采用有限元分析的方法对磁路进行仿真,对不同磁导率的磁轭材料进行分析。仿真结果表明绝大多数磁感线都通过多盘式离合器的磁流变液工作面,并且在相同条件下,相对磁导率较高的磁轭材料可以提高工作间隙的磁感应强度。     

楔槽式磁流变液离合器探究

通过对影响磁流变液离合器传递转矩大小的因素进行分析,在盘式磁流变液离合器基础上提出一种楔槽式磁流变液离合器的新结构形式,并用有限元的方法推导两者的力矩传递数学模型,通过计算比较两者传递力矩的大小,得出楔槽式磁流变液离合器能传递较大转矩的结论.     

磁流变液离合器离心力特性研究

介绍了磁流变液离合器的工作原理,分析了离心力对转矩的影响,推出了磁流变液离合器传递力矩的方程,为磁流变液离合器的设计提供理论依据.     

磁流变离合器的磁路设计研究

磁流变离合器的磁路设计是离合器设计中的重要环节,系统地分析离合器磁路设计中材料选择、磁路结构以及线圈参数等应该注意的因素。在此基础上,建立一套基于磁饱和效应的磁路设计方法,应用磁路欧姆定律计算磁路所需磁通势,详细介绍其设计计算步骤,并对电磁线圈参数的设计计算方法进行详细介绍,最后应用研究结果完成一种圆盘式磁流变离合器的磁路设计。     

圆盘式磁流变传动机构的设计与研究

利用磁流变液体可控的特性,将磁流变技术应用于机电传动与控制系统,在阐述磁流变传动机构工作原理基础上建立了其力矩模型,并就结构参数对机构动态品质、功率损失、调速范围等性能的影响进行了理论分析.分析表明,合理设计机构的结构参数将有利于减小机构功率损失、提高调速范围,并改善机构的动态品质.     

摩擦片式电磁离合器的测试及选用

从摩擦片式电磁离合器存在的问题、工作特性、性能测试等方面进行论述,提出了安装及选用摩擦片式电磁离合器应注意的事项。     

Wet clutch transmission fluid for AWD differentials: base fluid influence on friction characteristics

During the past few years several electronically controllable automotive transmission systems, where wet clutches are used as intelligent differentials, have emerged in the market. In this type of application the anti‐shudder properties of the lubricants are of vital importance. This paper investigates the influence of base fluids on the anti‐shudder properties of transmission fluids for wet clutches in all‐wheel‐drive systems. The investigated all‐wheel‐drive system featuring a wet multi‐plate clutch with a sintered brass‐based friction material is described. The test equipment used to determine the frictional characteristics of the transmission fluid is described. The parameters studied include base fluid type and base fluid viscosity. It is shown that the choice of base fluid has no impact on torque capacity, but that the base fluid influences the temperature dependence of the dynamic friction and the anti‐shudder properties. It is also shown that the major effect on the friction characteristics is caused by additive effects rather than base fluid effects. Copyright © 2006 John Wiley & Sons, Ltd.     

磁性液体触觉传感器的设计及特性研究

磁性液体兼具液体材料的流动性和固体材料的磁性,能够在重力场和磁场的作用下长期稳定存在。磁性液体具有独特的一阶浮力特性,在磁场梯度的作用下能够悬浮起比自身密度大的非磁性物体。基于磁性液体的一阶浮力特性,设计了一种新型的磁性液体触觉传感器。当接触压力作用在悬浮触棒的非磁性触点时,悬浮触棒的移动将引起霍尔元件处的磁场变化,进而输出电压信号。该结构能够进行接触压力、表面轮廓和微小位移的同时测量。该触觉传感器体积小,相比于传统的硅片式触觉传感装置成本更低。磁性液体相比于固体材料来说,能够在系统中起到缓冲吸能的作用,进而提高了传感器系统的耐冲击性。在0～0.09 N的接触压力测量范围内,测量精度能够达到10^-2 N量级,灵敏度3.34 V/N,线性度误差3.4%,迟滞误差1.4%,分辨率1.1%F.S.。     

基于挤压-剪切模式的高转矩磁流变离合器设计与实验

本文设计了一种基于挤压-剪切混合模式磁流变离合器,建立了用于测试其传动性能的实验装置。首先,介绍了磁流变离合器的工作原理;接着,利用ANSYS有限元仿真分析软件分析了磁路的磁感应强度分布特性;最后,搭建了磁流变离合器的传动性能实验测试装置,测试了磁流变离合器的静态传动性能和动态响应特性。实验结果表明:转速对磁流变离合器的转矩影响不明显,而电流和挤压应力对磁流变离合器转矩的影响比较大,转矩随电流及挤压应力的增加而增加;在1.0A的电流和40r/min的转速下,挤压应力为150kPa时,挤剪式磁流变离合器的转矩可达到146Nm,比剪切模式下的磁流变离合器转矩提高了约6.6倍;响应时间常数先随电流(电流小于0.6A)的增加而减小,而后受电流影响不明显;响应时间随挤压应力和转速的增加而下降;总体接合响应时间在77ms以内。所研制的基于挤压-剪切混合模式的磁流变离合器传动性能良好,控制灵敏。     

基于TRIZ理论的新型超越离合器设计分析

为了解决双涡轮液力变矩器中超越离合器可靠性低、使用寿命短的问题,运用TRIZ理论S曲线分析得到超越离合器的改进方向,并据此设计了一种新型超越离合器.该新型超越离合器采用低副动力传递原理,依靠滚珠与滑槽之间的正压力来实现动力传递.对其在不同运行状态下的受力情况进行了理论分析,分析结果验证了该超越离合器的强度符合设计要求,为此超越离合器投入生产提供了理论依据.     

交流电机与行星磁粉离合器组合调速方案研究

通过对磁粉离合器工作特性的研究,设计了行星轮式专用磁粉离合器,提出了交流电机与专用磁粉离合器组合装置实现无级调速的新方案,经分析计算、调试及试验,新方案体现了较好的调速性能。     

Mathematical model and experiment validation of fluid torque by shear stress under influence of fluid temperature in hydro-viscous clutch

The current design of hydro-viscous clutch（HVC） in tracked vehicle fan transmission mainly focuses on high-speed and high power. However, the fluid torque under the influence of fluid temperature can not be predicted accurately by conventional mathematical model or experimental research. In order to validate the fluid torque of HVC by taking the viscosity-temperature characteristic of fluid into account, the test rig is designed. The outlet oil temperature is measured and fitted with different rotation speed, oil film thickness, oil flow rate, and inlet oil temperature. Meanwhile, the film torque can be obtained. Based on Navier-Stokes equations and the continuity equation, the mathematical model of fluid torque is proposed in cylindrical coordinate. Iterative method is employed to solve the equations. The radial and tangential speed distribution, radial pressure distribution and theoretical flow rate are determined and analyzed. The models of equivalent radius and fluid torque of friction pairs are introduced. The experimental and theoretical results indicate that tangential speed distribution is mainly determined by the relative rotating speed between the friction plate and the separator disc. However, the radial speed distribution and pressure distribution are dominated by pressure difference at the lower rotating speed. The oil film fills the clearance and the film torque increases with increasing rotating speed. However, when the speed reaches a certain value, the centrifugal force will play an important role on the fluid distribution. The pressure is negative at the outer radius when inlet flow rate is less than theoretical flow, so the film starts to shrink which decreases the film torque sharply. The theoretical fluid torque has good agreement with the experimental data. This research proposes a new fluid torque mathematical model which may predict the film torque under the influence of temperature more accurately.     

Experiments on magnetic fluid rotary seals operating under vacuum conditions

Magnetic fluid rotary vacuum seals have been shown to be effective in machinery operating in a vacuum chamber. Such seals have the advantages of simple design, zero leakage at almost any rotation speed, and low friction. They have no wear and require no maintenance. This paper presents results obtained from experimental investigations of the operation of magnetic fluid rotary seals under vacuum conditions. The paper discusses the test apparatus and the seals used, the test conditions, and the procedure. The experimental results show characteristic phenomena observed in magnetic fluid rotary vacuum seals, including changes in vacuum pressure, temperature, and frictional moment dependent on the rotation speed of the shaft, number of sealing stages, height of the sealing gap, and mean magnetic flux density in the sealing gap.     

Preparation of magnetic fluid having active-gas resistance and ultra-low vapor pressure for magnetic fluid vacuum seals

The magnetic fluid, having an ultra-low vapor pressure property of 7·0×10⁻¹⁰ Pa at 293 K, was prepared. Hexafluoropropylene oxide polymer oil having high molecular weight was used as base oil. Magnetic particles were dispersed by using two types of new designed and synthesized hexafluoropropylene oxide acid derivative surfactants. The obtained magnetic fluid had a saturation magnetization of 35·0 mT, its magnetite particles were dispersed stably and showed a superior resistance to active gasses. It was ascertained that the magnetic fluid vacuum seal using the prepared fluid had the ultra high vacuum performance.