行星传动可控启动与无级变速装置研究

可控启动与无级变速是机械传动的发展方向,通过行星传动可控启动与无级变速装置的机械传动原理和控制原理,分析了该装置在软启动、软停车及无级调速与过载保护等方面具有较好的性能。     

啮合式准无级变速机构

本准无级变速机构为一变直径式链传动近似的无级变速装置,是一啮合式无级变速装置,可克服摩擦式无级变速机构的缺点,其优点是比摩擦式无级变速机构效率高、重量轻、寿命长、传动功率大;但它仍具有瞬时传动比变化等一般链传动的缺点。可用于对传动比精度要求不高的起重、运输、车辆等方面的传动,对某些生产自动线的传动也是合适的,是较简单、轻便的理想啮合式的近似无级变速机构。     

一种新型非圆锥齿轮无级变速装置

提出一种新型非圆锥齿轮无级变速装置,简述其无级变速的原理,并给出传动比函数的详细推导。同时,阐述位于其传动核心的一对非圆锥齿轮的设计方法,确定该装置的布局。基于ADAMS建立装置虚拟样机进行相应动力学仿真分析,以刚体动力学的方法导出其速度响应。结果表明,速度响应是在理论曲线的基础上上下波动,符合设计要求。     

新型机械式无级变速器的设计及优化

基于传动原理与变速原理,利用双曲柄机构的特性,结合棘轮机构传动的特点,提出一种新型机械式无级变速装置。运用解析几何及机构综合的方法,对该无级变速器的运动学规律进行研究,推导了传动比与机构参数的函数关系。为获得最优的机构设计参数,以实现无级变速器的传动比最大为优化目标,以双曲柄机构的形成条件、机构尺寸限制、传动角限制等为约束条件,编写优化设计程序并获得各个构件的优化长度。     

行星离心式新型机械无级传动基本工作特性研究

无级变速技术通过传动比的连续变化可以改善车辆的动力性和经济性,目前以金属带式无级变速器为主流形式。对无级变速传动装置进行创新设计,提出了一种新型的行星离心式机械无级传动方案,介绍了该传动方案的结构和工作原理,建立了动力学模型,获得了行星离心式新型无级传动机构的基本工作特性,同时对比分析了不同轨道曲线对工作特性的影响。研究结果为行星离心式机械传动的结构设计提供了依据,验证了行星离心式机械传动机构具有无级调速以及自适应输出转矩的特性。     

液压机械无级变速器设计方案分析

液压机械无级变速器是一种功率分流无级变速装置,通过液压调速机构实现无级调速,机械变速机构实现高效传动。自主设计了5种简单可靠的无级变速装置,通过液压调速机构和机械变速机构的不同组合方式,使变速器在液压传动、液压机械传动和机械传动间进行切换,分别满足平稳起步、田间作业和运输的要求,充分发挥了发动机的动力性和燃油经济性,并大大提升了变速器的传动性能和效率。为达到节能减排的目的,对变速器的蓄能装置和控制策略作了简单的介绍。     

《摩擦式行星传动无级变速器传动方案的探讨》

摩擦式行星传动无级变速器可以实现无级调速,简化传动方案。与其它型式的无级变速设备相比较,其主要优点是结构简单,维修操作方便,恒功率特性好,噪音低。其变速范围很广,理论上趋于无穷大。如果结构合理,可以从零转速起动,能适应变工况工作,在工业界受到越来越多的重视和应用。一、传动方案及结构参数分析 XZW型无级变速器传动方案如图1所示,此机构由输入轴1,输入圆盘2,行星锥轮3,调速环4,支承环5,输出圆盘6,加压盘7,加压弹簧8及输出轴9等构成。     

工业用变速宽V带(无级变速带)

宁波同步带总厂生产的无级变速带,是无级变速装置中的橡胶传动带,借助胶带在变速轮上的不同位置,达到任意调整传动比的目的,结构紧凑,传动平稳,效率高,能耗低,已成为发展迅速的一种新颖传动形式,可广泛应用于各     

销齿啮合式机械无级变速器设计

设计了一种销齿啮合式机械无级变速器,该无级变速器利用周转轮系的传动原理,实现了不依靠摩擦力传动的机械式无级变速。采用对称式的机构布局,通过调节无级变速器中调速机构的输入转速,实现输出机构的无级变速。     

一种结构新颖的摩擦式无级变速装置——自由滚珠式无级变速器

近年来,摩擦式无级变速器在国外获得了较快的发展。其传动功率从几十到几十千瓦,并可在接近于零到10000转/分的输出速度下工作;效率约为75％到95％。与传统的齿轮传动、链传动及皮带传动相比,不仅可实现无级变速,而且传动零件的形状比较简单,无需很高的精度,因此,加工费用较低。现已获得人们普遍地重视。目前国内使用的摩擦式无级变速装置大多属于图1所示的几种类型。其速比的变换是通过改变主动轮、从动轮和中间构件三者的相对位置来获得的。这些摩擦式无级变速器有如下一些共同的缺点:     

Rotational swashplate pulse continuously variable transmission based on helical gear axial meshing transmission

The current research on pulse continuously variable transmission(CVT) is mainly focused on reducing the pulse degree and making pulse degrees a constant value. Current research mainly confined to find out new design parameters by using the method of optimization, and reduce the pulse degree of pulse CVT and its range of variation. But the fact is that the reduction of the pulse degree is not significant. This article presents a new structure of mechanical pulse CVT-the rotational swashplate pulse CVT with driven by helical gear axial meshing. This transmission is simple and compact in structure and low in pulsatile rate (it adopts 6 guide rods), and the pulsatile degree is irrelevant to the transmission ratio. Theoretically, pulsatile rate could be reduced to zero if appropriate curved surface of the swashplate is used. Compared with the connecting rod pulse CVT, the present structure uses helical gear mechanism as transmission part and it avoids unbalanced inertial force in the former model. This paper analyzes the principle of driving of this transmission, presents its mechanical structure, and discusses its motion characteristics. Experimental prototype of this type of CVT has been manufactured. Tests for the transmission efficiency(when the rotational speed of the output shaft is the maximum) and the angular velocity of the output shaft have been carried out, and data have been analyzed. The experimental results show that the speed of the output shaft for the experimental prototype is slightly lower than the theoretical value, and the transmission efficiency of the experimental prototype is about 70%. The pulse degree of the CVT discussed in this paper is less than the existing pulse CVT of other types, and it is irrelevant to the transmission ratio of the CVT. The research provides the new idea to the CVT study.     

滚轮球面弧盘无级变速器的结构设计与运动学分析

滚轮球面弧盘无级变速器是一种新型牵引传动机械无级变速器,与半环型锥盘滚轮无级变速器相比,其本身具有正、反转输出,而且具有较高的使用寿命。本文介绍了该无级变速器的传动原理和结构设计特点,并对其进行了运动学分析。     

The influence of lubricating oil on the performance of a metal V‐belt‐type continuously variable transmission

The influence of lubricating oil on the torque capacity and the efficiency of a continuously variable transmission (CVT) of metal V‐belt type were experimentally investigated using a commercial CVT unit with a belt assembly and pulley. In order to analyse the friction characteristics of each of the contacting parts in the CVT, a block‐on‐disc type friction testing machine was used. The maximum torque capacity between the belt and pulley in the actual CVT correlated with the friction coefficient under high contact pressure (200 MPa) and relatively high sliding velocity (0.1 m/s) on the friction testing machine. The transmission efficiency decreased as the load decreased. The maximum difference in the efficiency between all the commercial automotive transmission and CVT fluids tested reached 6%. It was found that the requirements for the efficiency of transmission at a lower load were in contradiction with the maximum torque capacity.     

橡胶V带式无级变速器性能的测试与试验研究

首先给出了橡胶V带式无级变速器(CVT)的性能评价与试验方法;然后测试了一传递扭矩达120 N·m的橡胶V带式CVT的性能,给出了该CVT在不同输入转速与不同负载转矩下的传递效率、转矩损失、转速损失和速比的变化特性,并进行了分析;最后研究了橡胶V带式CVT主动轮限位弹簧的刚度、离心飞锤的质量以及从动轮的压扭弹簧的刚度对橡胶V带式CVT性能的影响,揭示了橡胶V带式CVT的结构参数对其性能的影响规律.     

Experimental investigation of temperature rise in elliptical EHL contacts

A toroidal traction drive continuously variable transmission (CVT) transmits power by the shearing action of lubricant film under heavy loads at contact points on the CVT rollers. In other words, rolling and sliding motions produce traction force. Furthermore, due to the geometry of the toroidal CVT, spin motion is produced at the contact points. These contact points, which are elliptical in shape, are where shear stress of the lubricant generates frictional heat. Temperature rise at the contact point has never been measured under the conditions of high rolling speed (velocity) and minute amounts of sliding (slippage), nor has the influence of spin motion on temperature rise been examined thus far. The authors et al. measured temperature distribution at contact points under conditions of high rolling speed and minute amounts of sliding, such as what is found in a toroidal CVT, using an FZG twin-disk test machine and thin-film sensors. The influence of spin motion on temperature rise was also experimentally investigated.     

车用无级变速器性能研究

本文作出了装配无级变速器(CVT)汽车动力特性图,同时通过一系列试验结果,对CVT汽车与配备其它变速器汽车在动力性、燃油经济性、传动效率、寿命、排放、可靠性、传递扭矩、成本、操纵性和舒适性等方面进行了详细的对比研究,详述了CVT与AT和MT之间的优缺点.     

TORQUE CAPACITY AND CONTACT EFFICIENCY OF A HALF TOROIDAL CONTINUOUSLY VARIABLE TRANSMISSIONS

The automotive industry is seeking new concepts for a continuously variable transmission (CVT) in the driveline. One possible solution for a CVT design is half toroidal traction drive, providing a high torque capacity with quick ratio change. An analytical study on the contact points of the half toroidal CVT has been detailed. The shapes of the contact areas among the input disk, power roller and output disk are considered ellipses. Mathematical equations for estimating the torque capacity, power loss due to spin action, and contact efficiency of the elliptical contacts of the half toroidal CVT are formulated and expressed in the form of integrals which can be readily evaluated by numerical scheme. The contact efficiency calculations of the half toroidal CVT have been developed for the proper spin point locations under the effect of system parameters. Numerical results are presented in graphical forms for considered parameters, which can help the designer to select the proper system parameters to minimi     

Car Fuel Economy Simulation Forecast Method Based on CVT Efficiencies Measured from Bench Test

Researchers face difficulties in studying the effects of driveline efficiency on car fuel economy via bench and road tests because of long working periods, high costs, and heavy workloads. To simplify the study process and shorten test cycles, a car fuel economy simulation forecast method for combining computer simulation forecasting with bench tests is proposed. Taking a continuously variable transmission (CVT) as the research object, a transmission efficiency model based on a bench test is constructed. An optimal economic variogram based on the original CVT variogram, the boundary conditions of vehicle performance, the road conditions and the driving behavior of the driver is generated in the Gear Shift Program (GSP)-Generation module in AVL Cruise. And on this basis a driveline simulation model that can calculate the fuel consumption based on the driveline data of a test car is built. The model is used to forecast fuel consumption and calculate real-time CVT efficiency under different conditions. Contrastive analyses on simulation results and real car drum test results are made. The largest error between simulation results and drum test results in driving cycles is 4.099%, which is 5.449% under constant velocity condition in driver control mode and 4.2% under constant velocity condition in automatic cruise mode. The results confirm the feasibility of the method and the good performance of the driveline simulation model in accurately forecasting fuel consumption. The method can efficiently investigate the effects of driveline efficiency on car fuel economy. Moreover, this research provides instruction for accurately forecasting fuel economy as well as references for studies on the effects of drivelines on car fuel economy.     

Steering control algorithm for efficient drive of a mobile robot with steerable omni-directional wheels

Omnidirectional mobile robots are capable of arbitrary motion in an arbitrary direction without changing the direction of wheels because they can perform 3-DOF motions on a plane. This paper presents a novel mobile robot design with steerable omnidirectional wheels. This robot can operate in either omnidirectional or differential drive modes, depending on the drive conditions. In the omnidirectional mode, the robot has 3 DOF in motion and 1 DOF in steering, which can function as a continuously variable transmission (CVT). The CVT function can be used to enhance the efficiency of the robot operation by increasing the range of the velocity ratio of the robot velocity to wheel velocity. The structure and kinematics of this robot are presented in detail. In the proposed steering control algorithm, the steering angle is controlled such that the motors may operate in the region of high velocity and low torque, thus operating with maximum efficiency. Various tests demonstrate that the motion control of the proposed robot works satisfactorily and the proposed steering control algorithm for CVT can provide a higher efficiency than the algorithm using a fixed steering angle. In addition, it is shown that the differential drive mode can give better efficiency than the omnidirectionaldrive mode.     

基于参数统计特征的无级变速车辆智能控制策略

装备无级变速器(Continuously variable transmission,CVT)的车辆采用经济性控制时,发动机后备功率小,急加速工况下只能通过提高转速来增加功率输出,而发动机转速提高要消耗相应功率,导致车辆动力不足。基于实时参数的控制策略只能在加速过程开始后再控制发动机工作点向动力性线偏移,这一过程仍需要通过提高发动机转速来实现,对提高CVT车辆的动力性作用有限。车辆行驶参数的统计值包含车辆行驶的历史信息,且能随行驶工况的变化而变化,这是制定控制策略的重要依据。针对已有控制策略的不足,在对各参数统计特征进行分析的基础上,提出根据行驶参数的统计值来调整发动机稳态工作线的控制策略。仿真及试验表明,新的控制策略能根据统计参数的变化合理调整发动机稳态工作点,对车辆工况变化具有自适应能力;同时,该控制策略避免了对实时参数的依赖,可以在某一动态过程开始前就使发动机工作在后备功率较大的稳态工作线上,有利于提高动态过程的动力性。