提升机盘式制动器闸瓦摩擦学特性试验与机理分析

发布时间：2018-05-03 20:08

本文选题：改性酚醛树脂 + 树脂基闸瓦　；参考：《太原理工大学》2017年博士论文

【摘要】：制动装置作为关键的安全保障设备,是机械系统的重要组成部分。在机械装备的工作过程中,制动装置可靠的运行对提高装备控制系统、操纵系统乃至整机的可靠性具有举足轻重的作用。伴随着生产运输装备的大型化、高速化、高载化发展趋势,产生了对大型装备实施可靠制动的严苛的需要,意味着制动摩擦产生热量更多,闸瓦摩擦表面温升更快、更高,要求闸瓦具有较高的摩擦系数稳定系数,及较低的磨损率。有机基摩擦材料由于高分子树脂基摩擦材料基体在高温下易发生热分解,导致摩擦系数大幅度下降,磨损率急剧增大,这就限制了有机摩擦材料在更广泛领域推广使用。制动闸瓦是制动系统工作执行部件,它的摩擦磨损性能与制动安全有直接关系,因此,开展制动闸瓦的摩擦学特性试验,分析其机理,具有重要的理论价值和实践意义。本文以提升机盘式制动器闸瓦材料为研究对象,以提升机实际制动工况参数为参考,开展摩擦学特性试验,对其在取不同制动压力、滑动速度及摩擦表面温度时的摩擦学特性进行系统全面的测试,获得大量的试验数据,并以试验数据为基础,分析其摩擦磨损机理,获得一些具有实践意义的理论成果。首先,实施闸瓦材料综合测试,对闸瓦材料在综合测试中的摩擦性能变化进行表征。在分析闸瓦在制动过程中制动摩擦力的组成及种类的基础上,对不同工况条件下瞬态摩擦系数随时间的变化规律研究,获得瞬态摩擦系数突变现象的判别式。分析了制动压力、滑动速度及摩擦表面温度变化过程中平均摩擦系数的变化特征。分析了定温变压变速、定压变温变速、定速变温变压等情况对平均摩擦系数、其稳定系数及其离散程度的变化规律,得出其变化机理。其次,建立了平均摩擦系数统计分析的理论基础。选择平均摩擦系数样本值的标准偏差考察平均摩擦系数的离散程度,以平均摩擦系数标准偏差的变化曲线为基础,并以提出的三个判据为依据,进行了闸瓦材料摩擦性能的机理分析。考虑到pv机理图在闸瓦材料摩擦学设计中的重要作用,提出以组合参量考察、表征及分析闸瓦材料平均摩擦系数的观点,系统的研究了多种组合参量,分析了组合变量-平均摩擦系数曲线的性质及内在的摩擦学机理。通过对组合参量-平均摩擦系数的关系曲线分析,得出了组合参量与单参量的优缺点,并获得不同曲线在总体趋势、震荡性、突变性等的不同表现。基于单参数、组合变量的平均摩擦系数变化曲线特性,建立了组合变量-平均摩擦系数的关系模型。提出了失效概率空间的获取方法,求出了失效概率空间,并就该模型的应用进行了例证。这些内容既是闸瓦制动系控制系统安全运行的必要条件,也是材料摩擦学设计的边界条件,对于摩擦学设计和摩擦学控制具有不可忽视的意义。同时工况参数-摩擦系统安全关系模型的研究思路和数据处理办法适用于其它摩阻材料性能研究,具有普遍意义,甚至增摩材料亦可应用。并且闸瓦材料试验获得的各种单参数、双参数、三参数及多参数摩擦系数变化特征曲线,不仅是摩阻材料设计理论的丰富,而且作为实测数据可以用来进行材料摩阻行为的安全校核及可靠性计算而服务于工业生产。再次,对闸瓦试样在测试中获得的磨损数据进行分析处理。对闸瓦试样磨损的系统特性及影响因素简单介绍,并针对闸瓦材料粘结剂热分解温度之前与之后磨损机理的不同,考察了闸瓦磨损量随时间的变化规律及机理、磨损率-时间曲线变化规律及机理和不同摩擦表面温度下闸瓦表面形貌的影响。分析闸瓦摩擦表面温度不同时,制动压力、滑动速度对闸瓦材料磨损率及磨损率稳定系数的影响机理,同时分析了制动压力、滑动速度对闸瓦材料磨损率离散程度的影响机理,获得非常丰富的规律性结论。提出了一种基于磨损面积扩散率的闸瓦寿命计算方法,经过例证,与实践基本相符。最后,对闸瓦试样在热分解阶段的混合摩擦机制进行了探讨。通过闸瓦材料在热解阶段的摩擦磨损实验,实验验证了在制动压力、制动速度变化时,闸瓦材料的平均摩擦系数的变化。从热分解阶段磨损后的闸瓦材料的微观形貌入手,分析其在热分解阶段的微观形貌变化,并分析了产生这种变化的机理。详细阐述了闸瓦材料在热分解阶段的产物,分别分析了氧化膜、气垫膜、转移膜等的成分和产生机理。从表面膜的结构上分析了不同工况参数对表面膜润滑的影响,重点分析力表面膜润滑中的薄膜润滑,并根据薄膜润滑机理提出了摩阻材料的2个设计准则。在推断表面膜润滑符合牛顿流体特性的基础上,给出了闸瓦材料热分解表面膜的摩擦系数近似计算方法。
[Abstract]:As the key safety equipment, the brake device is an important part of the mechanical system. In the working process of the mechanical equipment, the reliable operation of the brake device plays an important role in improving the reliability of the equipment control system, the control system and the whole machine. The development trend produces the stringent requirements for the reliable braking of large equipment, which means that the brake friction produces more heat, the friction surface temperature rises faster and higher, and the brake shoe has a higher coefficient of friction coefficient stability and lower wear rate. The organic rubbing material is at high temperature due to the polymer matrix friction material base at high temperature. It is easy to cause thermal decomposition, resulting in a large drop in friction coefficient and a sharp increase in wear rate. This restricts the spread of organic friction materials in a wider range of fields. Brake brake shoes are the executive components of the brake system. The friction and wear properties of the brake shoes are directly related to the safety of the brake. The mechanism is of great theoretical and practical significance. In this paper, the brake shoe material of the hoist disc brake is taken as the research object. The tribological characteristics test is carried out with the reference of the actual braking parameters of the hoist, and the tribological characteristics of the brake are tested in a systematic and comprehensive way when the brake pressure, the sliding speed and the friction surface temperature are taken. A lot of experimental data are obtained and the friction and wear mechanism is analyzed on the basis of the test data. Some practical theoretical results are obtained. First, the comprehensive test of the brake shoe material is carried out to characterize the change of the friction properties of the brake shoe material in the comprehensive test. The composition and the species of brake friction force during the brake process are analyzed. Based on the study of the variation of transient friction coefficient with time under different working conditions, the discriminant of transient friction coefficient mutation is obtained. The change characteristics of the average friction coefficient in the braking pressure, the sliding velocity and the friction surface temperature change are analyzed. The constant temperature variable pressure change, constant pressure variable temperature change and fixed speed change are analyzed. The change mechanism of the average friction coefficient, the stability coefficient and the variation of its discrete degree are obtained. Secondly, the theoretical basis of the statistical analysis of the average friction coefficient is established. The standard deviation of the average friction coefficient is selected to examine the discrete degree of the average friction coefficient and the standard deviation of the average friction coefficient. Based on the change curve and based on the three criteria proposed, the mechanism analysis of the friction properties of the brake shoe material is carried out. Considering the important role of the PV mechanism diagram in the tribological design of the brake shoe material, the viewpoint of the investigation, characterization and analysis of the average friction system number of the brake shoe material is put forward. The properties and internal Tribological Mechanism of the combined variable - average friction coefficient curve are analyzed. Through the analysis of the relation curve of the combined parameter - average friction coefficient, the advantages and disadvantages of the combination parameter and the single parameter are obtained, and the different curves in the general trend, the concussion and the mutagenicity are obtained. Based on the single parameter and the combination variable The relation model of the average friction coefficient change curve is set up. The method of obtaining the failure probability space is put forward, the failure probability space is obtained, and the application of the model is illustrated. These contents are not only the necessary condition for the safe operation of the brake system of brake system, but also the tribology of the material. The boundary conditions designed can not be ignored for tribological design and Tribological control. At the same time, the research ideas and data processing methods for the safety relationship model of the working condition parameter friction system are applicable to the performance study of other friction materials. It is of universal significance, and even the rubbing material can be applied. And the test of brake material is obtained. The variation characteristic curve of a variety of single parameters, double parameters, three parameters and multi parameter friction coefficient is not only rich in the design theory of friction material, but also used as the measured data for the safety checking and reliability calculation of material friction behavior and for industrial production. Thirdly, the wear data obtained in the test of the brake shoe specimen are entered. The system characteristics and influencing factors of the wear of the brake shoe specimen are briefly introduced. In view of the difference between the wear mechanism before and after the thermal decomposition temperature of the brake shoe material, the change law and mechanism of the wear amount of the brake shoe with time, the change law and mechanism of the wear rate time curve and the brake shoe under the different friction surface temperature are investigated. The influence of surface morphology is analyzed. The influence mechanism of the friction surface temperature, brake pressure, sliding speed on the material wear rate and wear rate stability coefficient of brake shoe is analyzed, and the influence mechanism of brake pressure and sliding speed on the dispersion of material wear rate of brake shoe is analyzed, and a very rich regular conclusion is obtained. A kind of basis is put forward. The calculation method of the life span of the brake shoe with the wear area diffusivity is exemplified, which is basically consistent with the practice. Finally, the mixed friction mechanism of the brake shoe specimen in the thermal decomposition stage is discussed. Through the friction and wear experiment of the brake shoe material at the pyrolysis stage, the experiment proves the average friction of the brake shoe material when the brake pressure is changed and the braking speed is changed. The change of the coefficient is analyzed from the microscopic morphology of the brake shoe material after the thermal decomposition stage. The microstructure changes in the thermal decomposition stage are analyzed, and the mechanism to produce this change is analyzed. The products of the brake shoe material in the phase of thermal decomposition are described in detail, and the composition and production mechanism of the oxide film, air cushion film and transfer film are analyzed. The influence of different working conditions on the surface film lubrication is analyzed in the structure of the surface film. The film lubrication in the force surface film lubrication is emphatically analyzed. According to the film lubrication mechanism, the 2 design criteria of the friction material are put forward. On the basis of inferred that the surface film lubrication is in conformity with the Newton fluid characteristics, the friction surface mask of the brake shoe material is given. Approximate calculation method of friction coefficient.

【学位授予单位】：太原理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TH134

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