英文资料及其翻译.doc

无级变速传动 金属带 主 从动锥盘Along with the development of economics, the increment of population, and the improvement of traffic conditions automotives have been used widely, its number increasing year after year. Then developing perfect vehicles transmission system is becoming more and more urgent. Compared with conventional multiratio gearbox, the metal V-belt continuously Variable Transmissions have attracted a great deal of interest because of their economy, drive performance and comfort. Now many big motor corporations all over the world are investing huge money to investigate them. In this thesis, its history, current status, and the dimension parameters and function of principal structures are described. Through the analysis of its working progress, the author explained the superiority and advantage of this device. For the metal V-belt CVT, the belt transmission device is the hardcore, and one of its key parts is the pulley. It affects the transmissionquality, the efficiency and the life and cost of the CVT. To straight generatrix pulleys, while the transmission ratio isnt one to one, the matal belt will retort, resulting in the declining of the belts life. In this thesis, the reason of retorting and the relation between the deflection and transmission ratio are analyzed. The author tesified that the pulleys genetrix shouldnt be straight if there is no deflection happening. The object of this thesis is to design the curve genetrix to meet requirements. Defining the mesh point between metal block and pulley as the initial point, the surface within the initial point as the inner prick, the surface outside the initial point as the outer one. Analyzing the relative movement between pulleys and metal blocks separately to acquire their onnection formula. Only when the numerical values meet this formula wont the metal V-belt deflect. From the connection formula between pulleys and metal blocks, we know the genetrix which meet the formula is not one and only. Considering the contact stress between pulleys and metal blocks affect carrying capacity of the CVT, the author tried to choose one genetrix which can reduce the stress to the minimum. So the contact stress is considered as the target function of optimized designing, and many other factors are considered such as equation restriction and inequality restrictions. In the optimized designing the two-dimension variables are the tangent slope of the mesh points. In this thesis serial nonrestrict minimum method is applied to seek the best mesh points. It begins from the initial point and gets a pair of mesh points per step. After the movable pulleys reach the maximum position, this alternative ends and then the numerical values of the pulley genetrix are obtained. Compared with other genertrix the contact stress ont his optimized one has reduced 10 percent appromixedly. In this thesis the author also analyzed the effect of important parameters. By changing the initial parameters she got other numerical values of the genetrixs and calculated the contact stress. After analyzing and comparing the different results the author get the reasonable initial parameters and more perfect numerical values of the pulleys genetrix. Based on the numerical values the author drew the pulleys genetrix, which is the improvement on the straight one. It not only meets the requirement that the offset of the belt is zero in the timing, but also reduces the contact stress to the minimum, and then helps to enhance the carrying capacity of the CVT, taking on certain practical meaning. . Kinematic characteristics include principle of shifting ratio, ratio range, slipping principle between MVB and pulleys, steel ring and pushing blocks, steel rings each other. kinetic characteristics include driving principle, forces acting in MVB, pushing blocks compressive force distribution and rings tension force distribution in different ratio and the transmitted torque, changing condition of each force during steady state and transitional states. In addition, calculation formula is established between pushing force of driven pulley and transmitted maximum torque.Mechanics of steel ring group that is one of CVTs key part is emphasized in this thesis, numerical models of static state and driving state are proposed respectively. Excess fitness is adopted to bring about the present state in the steel ring group. As a result, load distribution in steel rings is even. The computational formula between excess quantity and transmitted torque is derived. The theoretical base for assembling ring group is provided. In addition, the computational formulas on tension force of each ring in driving state, stress changing pattern, position of maximum stress and minimum stress are derived. Invalidation , design criterion and design method on steel ring is given with a simple. Factors that influence steel ring load capability are analyzed and corresponding measures are provided. At last, stress tests of single ring and outermost ring of steel ring group at static state and driving state are done on the special experiment devices, and quite good agreement between experimental results and calculated results can be found. It confirms that the present models are useful and valid. We have not found that any figurable design method for steel ring is given in the existing paper. Thereby, calculation is simple and rough in the previous design. The approach in this thesis is more overall and rigorous, valid design method is derived. The works has fairly good reference value and practice meaning for metal V-belt 无效 CVTs research and design.中文翻译： 随着经济的发展、人口的增加、交通路况的改善，汽车的应用日益普遍，其数量逐年增加。而研制理想的汽车传动系便成了日益迫切的问题。由于金属带式无级变速器与传统的多档齿轮箱相比，具有更高的经济性、动力性、及安全舒适性，因而引起了广泛的注意力，世界各大汽车公司纷纷投巨资研制。介绍了金属带式无级变速器的发展历史、研究现状及发展趋势。对其组成部分及基本结构做了深入剖析，给出了关键部件的尺寸设计参数，并简略地说明了各部分的功能及作用。通过对其工作过程的分析，进一步说明了金属带式无级变速的变速原理决定了该变速装置的先进性和优越性。 从运动学和动力学两方面详细介绍了金属带式无级变速器的传动原理，作出了基本假设，建立了传动系统的简化的数学模型。通过扩展传统的平带传动理论，分析了复合金属带特有的传动特点。详细分析了在恒速及调速两种状态下，钢片与钢带随传动比和输入扭矩的变化而变化的力学性能及运动趋势，介绍了金属带传动中的滑差理论及滑差率的定义。并且单独分析了金属带环组每一层薄带的受力情况以及单元摩擦片所受的各个力，分别建立了钢带拉应力及摩擦片挤压力的数学表达式，直观地表达了这些力与金属带的结构参数、材料参数等相互间的关系。由于在无级变速器中，带传动装置是核心部分，而工作带轮又是带传动装置的关键部件，它直接影响着传动质量、传动效率及变速器的寿命和成本。现有的直母线锥盘在传动比不为1时，由于两个可动锥盘的轴向移动量不同，导致了金属带的偏移和扭转，使带的寿命急剧下降。本文取摩擦片为圆弧形，在控制主从动锥盘的轴向移动量相同的条件下，对原有的锥盘廓线进行改进。 对锥盘和摩擦片的变速运动进行解析，求得内外啮合点处的摩擦片与锥盘的啮合运动关系式。由于钢片与锥盘间的接触应力直接影响着变速器的承载能力，因而把接触应力作为优化设计的目标函数，利用降维原则将锥盘母线的优化设计问题转化为以内外锥面上啮合点处的半楔角为设计变量的二维问题。根据已分析的带拉力及摩擦片挤压力的数学表达式，将与锥盘形状相关的挤压力作为强度约束条件；对于与之无关的环带，单独探讨了环带拉应力最小时环带组的设计方法。本文以可动锥盘的轴向移动量作为步长迭代，从初始啮合点开始，应用序列无约束极小化方法下一个啮合点处的接触应力最小时半楔角的大小，并根据啮合关系式求出该啮合点的坐标值。根据求出的数值解作出的锥盘廓线，是