盘式制动器摩擦特性及其热力耦合分析

发布时间：2018-03-19 02:01

本文选题：盘式制动器　切入点：摩擦特性　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：带式输送机具有运行平稳、连续性以及抗干扰性强等特点,是颗粒及块状物料的理想运输设备。目前带式输送机已经朝着长距离、高速、重载方向发展,为了满足煤炭的安全运输,这就对其制动性能提出了更高的要求。盘式制动器具有散热性能好、稳定性高、制动力矩大及结构紧凑等优点,很好地满足了带式输送机的工作要求。在制动过程中,经常出现热衰退、热裂纹以及材料磨损等问题,严重制约着盘式制动器的工作性能。因此,有必要对摩擦副接触表面的摩擦特性以及热力耦合行为进行分析。本文首先在热分析理论的基础上,建立了有限元模型。通过摩擦磨损试验,选取不同制动压力和制动速度,在干摩擦和水润滑条件下分别对树脂基摩擦片和铜基摩擦片的摩擦磨损变化规律进行测试。结合表面微观形貌分析可知,铜基摩擦片的摩擦稳定性比较好,耐磨性强。利用ABAQUS计算出制动盘表面的温度、热变形和热应力特性曲线,从轴向、径向和周向对制动盘进行三维瞬态热力耦合分析。随着制动压力和制动速度的增加,热变形逐渐增加,温度特性曲线和应力特性曲线近似直线上升。而制动压力为35MPa对应的温度是环境温度的4.8倍,对应的热应力是制动压力的5.6倍。热变形是由摩擦热引起的,温升较低时,热变形变化不明显。而在2s—4s内,热变形近似直线增加。通过应力场和温度场的云图分布可知,接触处的温度和应力比较大,并向两侧非接触区域减小,结合最大温度和最大应力的动态特性曲线,发现温度和应力变化趋势基本一致,说明温度场和应力场是相互耦合的。根据不同运行工况下的系统试验,发现制动盘转速为3r/s时,在系统压力从6MPa减小过程中,所需的制动时间大约为16s。利用制动盘摩擦进出口的温度测试结果与仿真温度对比,发现两者之间的温差在5%以内,说明盘式制动器的简化模型在理论上是可行的。
[Abstract]:Belt conveyor has the characteristics of smooth operation, continuity and strong anti-interference. It is an ideal transportation equipment for grain and block material. At present, belt conveyor has been developed towards long distance, high speed and heavy load. In order to meet the safety of coal transportation, it puts forward higher requirements for its braking performance. Disc brake has the advantages of good heat dissipation, high stability, large braking torque and compact structure, etc. It meets the requirements of belt conveyer very well. During the braking process, there are many problems such as heat decay, hot crack and material wear, which seriously restrict the working performance of disc brake. It is necessary to analyze the friction characteristics and thermo-mechanical coupling behavior of the contact surface of the friction pair. Firstly, based on the thermal analysis theory, a finite element model is established. Through friction and wear tests, different braking pressures and braking speeds are selected. The friction and wear characteristics of resin based friction sheet and copper base friction sheet were tested under dry friction and water lubricating conditions respectively. The friction stability of copper based friction sheet was better than that of copper based friction sheet, according to the analysis of surface morphology. The characteristic curves of temperature, thermal deformation and thermal stress on the surface of brake disc are calculated by ABAQUS, and the three dimensional transient thermodynamic coupling analysis of brake disc is carried out from axial, radial and circumferential directions. With the increase of braking pressure and braking speed, The thermal deformation increases gradually, the temperature characteristic curve and the stress characteristic curve rise approximately straight line, and the temperature corresponding to 35 MPA is 4.8 times that of the ambient temperature, and the corresponding thermal stress is 5.6 times of the braking pressure. The thermal deformation is caused by friction heat. When the temperature rise is low, the change of thermal deformation is not obvious, but in 2s-4s, the thermal deformation increases approximately in a straight line. According to the distribution of the cloud diagram of stress field and temperature field, the temperature and stress at the contact point are relatively large and decrease to the non-contact region on both sides. Combined with the dynamic characteristic curve of maximum temperature and maximum stress, it is found that the variation trend of temperature and stress is basically the same, which shows that the temperature field and stress field are coupled with each other. According to the system test under different operating conditions, it is found that when the speed of brake disc is 3 r / s, When the pressure of the system decreases from 6 MPA to 6 MPA, the braking time is about 16 s. By comparing the temperature test results of friction inlet and outlet of brake disc with the simulation temperature, it is found that the temperature difference between the two is less than 5%. The simplified model of disc brake is feasible in theory.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD528.1

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