【作者】 孙铎；

【导师】 秦四成；

【作者基本信息】 吉林大学 ， 机械设计及理论， 2012， 硕士

【摘要】 轮式装载机作为一种土方机械，它的工作环境复杂多变，工作场地条件恶劣。装载机经常会遇到两侧轮胎路面附着条件不同的情况，路面附着条件的差异会产生不同程度的轮胎滑动。过度的轮胎滑动会造成装载机通过性、驱动性和燃油经济性变差，工作效率降低。同时，轮胎的滑动也是导致轮胎磨损，影响轮胎使用寿命的重要因素之一。现代装载机多采用在驱动桥装配限滑差速器来解决以上问题。较常见的是在前驱动桥装配摩擦片式限滑差速器，部分装载机在前、后驱动桥都有装配。在驱动桥上装配摩擦片式限滑差速器在不同程度上改善了由轮胎过度滑动带来的诸多问题。因此，本文主要内容是通过研究摩擦片式限滑差速器的工作原理和特性，分析不同驱动桥配置对装载机驱动性、燃油经济性、工作效率和轮胎滑转率等方面的影响。虽然摩擦片式限滑差速器在轮式装载机上的应用在一定程度上改善了装载机的实用性，但仍存在一定的局限性。比如在转向过程中，摩擦片式限滑差速器不能解锁，影响了装载机的转向能力，降低传动系统的效率，增加轮胎磨损。另外，其锁紧系数不能调节，影响到其对不同工况的适应性和传动系统的效率。所以，本文的另一部分内容是在前面研究的基础上探讨电控限滑差速器在轮式装载机上的应用性。本文主要做了以下的工作：1．通过对摩擦片式限滑差速器的结构特性和工作原理的分析，推导了摩擦片式限滑差速器的数学模型。在此基础上，从动力学及运动学角度入手，推导了主动式限滑差速器的数学模型，在MATLAB/SIMULINK环境中建立了二者的仿真模型；2．基于80型轮式装载机建立了铰接式车辆8自由度车辆动力学数学模型、动力传动系统数学模型，并在MATLAB/SIMULINK环境下建立了车辆动力学、动力传动系统和轮胎力学的仿真模型；3．分别设计了装载机直线行驶和转向行驶过程中主动式限滑差速器的控制策略。根据实际情况，设定了四种驱动桥配置（配置1：前、后桥装配主动式限滑差速器；配置2：前、后桥装配摩擦片式限滑差速器；配置3：前、后桥装配开式差速器；配置4：前桥装配摩擦片式限滑差速器，后桥装配开式差速器）。在几个典型工况和不同路面条件下，对以上四种驱动桥配置对装载机各项性能的影响进行对比分析。得到的主要结论有：1．直线行驶时，在极端路面条件下，配置1和配置2装载机能保证装载机的通过性，在行驶速度和牵引效率方面前者优于后者；在一般路面条件下，配置1、配置2和配置4装载机都能保证车辆较好的驱动性能。由于锁紧系数不能调节，摩擦片式限滑差速器相比于主动式限滑差速器在差速器传动效率方面略显不足，影响了传动系统效率；2．转向行驶时，配置1装载机转弯半径最小，有利于工作效率的提高，配置2和配置4装载机转弯半径较大。相对于配置2和配置4，配置1装载机能降低轮胎的磨损，提高装载机转向轻便性；3．在V型作业循环工况下，相对于配置3，配置1、配置2和配置4装载机完成一次作业循环的时间分别降低了6.2%、3.4%和2.7%；完成一次作业循环所消耗的燃油量分别降低了7.5%、4.7%和3.5%；铲入深度分别提高了13.9%、7.8%和3.5%。配置1和配置2装载机都能降低轮胎滑转量，相比之下前者能更大程度降低轮胎磨损。更多还原

【Abstract】 As a type of earth moving machinery, Wheel loaders are mainly operated on roughterrain with complex work environment. They are often encountered on the terrain withdifferent adhesion conditions between tires. The differences of the road-tire adhesioncoefficients will produce different levels of tire sliding. Excessive sliding of the tires canlower the drive performance, transmission efficiency, passing ability and fuel economy. Inaddition, the slip rate of the tires is one of main factors affecting the critical wear life ofwheel loader tires.At present, limited-slip differential is usually assembled in drive axle of modernwheel loaders to solve the above problems, most in front drive axle, others in both frontand rear drive axles. The series of problems caused by excessive tire sliding can beimproved at some level by the application of drive axle with limited-slip differential.Therefore, the main purpose of this paper is analyzing the impact on drive performance,transmission efficiency, passing ability and fuel economy of loaders produced by the aboveimprovements, based on the study of the working principle and characteristics oflimited-slip differential.The previously mentioned problems have been improved by the application oflimited-slip differential to a great extent, but limitations still exist. For example, in thesteering process, the limited-slip differential can not be unlocked which will affect theloader’s steering ability, reduce the transmission efficiency and decrease tire wear. Inaddition, the locking coefficient can not be adjusted, which will also affect its adaptabilityto different working conditions and transmission efficiency. So, another part of the purposeof this article is to explore utility of the electronically controlled differential on wheelloaders in the basis of previous studies. In this paper, the following work is completed:1. The derivation of the limited-slip differential mathematical model and establishmentof the simulation model is completed by the study of Structural characteristics and workingprinciples. mathematical model and simulation model of active differential are alsoobtained at dynamics and kinematics point of view.2. Mathematical model of8-DOF vehicle dynamics, powertrain system and tire dynamics are deduced based on80type wheel loader. And the simulation model is built inMATLAB/SIMULINK environment.3. The control strategy of active differential is designed separately based on thedriving and steering process. According to the actual situation, four types of driveaxles(type1:with active differentials in both front and rear drive axles; type2:withlimited-slip differentials in both front and rear drive axles; type3:with open differentials inboth front and rear drive axles; type4:with limited-slip differential in front drive axle, withopen differential in rear drive axle;) configuration are designed. in several typical workingconditions, the impact of the four types of drive axle on loaders has been analyzed.The main conclusions are:1. In extreme road conditions, loader with type1and type2drive axles can ensure itspassing ability, in consideration of adaptability to the extreme road conditions, former issuperior to the latter, mainly in the vehicle speed and traction efficiency. Under normalroad conditions, loader with type1, type2and type3drive axles can guarantee the driveperformance. The locking coefficient of limited-slip differential is un-adjustable, whichaffects its adaptability to different working conditions and transmission efficiency.2. In steering process, loader with type1axle can turning with a smaller radius, whichis beneficial to working efficiency. By contrast with type2and type3, loader with type1axle can enhance the tire wear, and improve the steering portability.3. In V type operation cycle condition, by contrast with type3, loader with type1,type2and type3reduce the time6.2%,3.4%and2.7%, respectively. And the fuelconsumption is reduced by7.5%,4.7%and3.5%, respectively. Depth of Shoveling isincreased by13.9%,7.8%and3.5%, respectively. Loader with both type1and type2driveaxles could lower the amount of sliding, the former is advantageous in reducing the tireattrition.更多还原