Prediction of the cooling factors of a vehicle brake disc and its influence on the results of a thermal numerical simulation

In the process of developing the brake disc, it is necessary that we predict the suitability of the design. In this manner, we can affirm that even the first prototype will satisfy all of the customer homologation requests. Usually those comprise different sequential braking tests in which the maximal achieved temperature is the criterion that governs brake disc suitability. The knowledge of how to predict the behavior of a brake disc in the early pretesting phase has a significant impact on development costs and time. The common method that is used for predicting the temperatures in the brake disc during braking is numerical simulation analysis. With the help of Computational Fluid Dynamics, the flow through a vehicle ventilated brake disc of known geometry was determined, and the wall heat transfer coefficients for all vehicle speeds and brake disc temperatures were calculated. The results were then imported into a thermal numerical simulation of a sequential-braking vehicle test. The results showed that the consideration of cooling factors has a significant impact on temperature courses. To obtain accurate results from the numerical simulation and to simulate the vehicle test precisely, the proper wall heat transfer coefficients must be considered. The proposed method produces more accurate numerical results and enables the development engineer to develop suitable brake disc geometry in the early pretesting phase.     

BIR制动器驻车力矩计算方法

盘式制动器以其制动性能好等优点被广泛应用于各种汽车上,文章对BIR制动器的驻车原理进行了详细分析,介绍了2种盘式制动器驻车力矩的计算方法,并通过某车型进行了实际验证,其结果是驻车制动力的总和大于该车在测试状态下整车质量的20％,满足法规要求,表明了算法的有效性。     

Measurement of the disc-pad friction coefficient for mechanical brakes using direct and indirect methods

It is necessary to guarantee the proper brake force to stop a train safely in a limited distance and o adjust its speed. Currently, most trains are run by electrical power and have a combined electrical and mechanical (friction) braking system. The mechanical brake force is determined by many parameters, such as the friction coefficient of the brake disc and pad, the pressure in the brake cylinder, the brake cylinder’s cross sectional area and the brake linkage ratio. In general, the friction coefficient data of the brake disc and pad have been taken through a dynamo-test in a laboratory, but these data might not be well matched with real data under operating conditions because of the difference in data acquisition conditions. The present study examined two methodologies that can measure the friction coefficient of the brake pad and disc based on a train’s real operating conditions. The first method was the direct method, which measured the brake force and clamping force applied on the mechanical brake by using strain gauges installed on the brake to calculate the friction coefficient. The second was an indirect method that obtained the friction coefficient by using the weight of the train and the equivalent brake force. Those variables were calculated from the longitudinal dynamic characteristics, such as resistance to motion, gradient resistance and curved resistance. These two methodologies were used to obtain the disc-pad friction coefficient for the mechanical brakes of a Korean high-speed train (HSR350x).     

摩擦材料摩擦特性对轿车前,后制动力之比的影响

本研究了摩擦材料摩擦特性对轿车（盘式），后（鼓式）制动器制动力之比的影响。根据对前，后制动器部总成大量的测功器试结果，计算并绘出前，后制动之比值随制动管路压力，车速，制动温度的变化关系曲线，并与设计作了对比分析，讨论了它对轿车制动稳定性的影响，为制动性能计算，制动器设计和制动衬片摩擦材料的选配提供依据和参考，从而保证了轿车的制动稳定性。     

汽车气压盘式制动器的结构特点与性能分析

介绍了几种国内外重型汽车气压盘式制动器的结构及其特点,从左右轮制动力差异,制动器的效能因数与摩擦系数的关系及迟滞量等方面对盘式制动器与鼓式制动器进行性能对比分析,说明盘式制动器在制动效能、制动效能的稳定性以及制动时汽车的方向稳定性上比鼓式制动器具有明显的优势,理论和试验表明盘式制动器与ABS、ASR、EBS等系统匹配时可简化系统结构、优化系统性能,并对重型汽车装用盘式制动器带来的制动系统的相关问题进行了探讨.     

Estimation of the adhesion force for a disc brake in a skid control condition

The performance of brakes has become important due to increased train speeds. The brake system of a train must possess a large brake force to stop the train safely within a limited stopping distance. However, an excessive brake force deteriorates the ride comfort and causes the train to skid. Therefore, it is necessary to control the brake force within the adhesion force limit. This paper presents an analytical method to estimate the relationship between the brake and adhesion forces of a disc brake system. This method has been applied to the actual disc braking control system of the Korea High-Speed Train (HSR350x), and the adhesion force is estimated in an actual skid condition.     

FSC赛车制动系统设计

本文提出了一套适用于FSC赛车制动系统的设计方法。选用简单液压盘式制动系统，并且加装平衡杆以调节制动器制动力分配系数。计算和分析表明，该制动系统能够满足比赛时动态测试的要求。     

某型轿车盘式制动器制动噪声的控制

对某型轿车盘式制动器进行了台架试验,发现该制动器主要制动噪声频率在3kHz附近。采用有限元FEA分析手段对制动盘、制动钳壳体、制动钳支架和摩擦片进行了振动特性分析。结果表明,制动钳支架的7阶振动模态是导致制动噪声产生的原因之一。对制动钳支架结构设计进行了改进,并对装有改进后制动钳支架的盘式制动器进行了台架试验。结果表明,制动器冷态制动噪声从100.5 dB下降为73.4 dB,达到了该车型对制动器噪声的限值要求。     

Heat transfer enhancement on ventilated brake disk with blade inclination angle variation

Ventilated brake disk is the state of the art technology in automobile braking system. It is well known that the braking capability of brake disk is affected by the rate at which heat is dissipated through forced convection. The rapid increase and decrease of the brake disk temperature could lead to catastrophic failure of the brake disk due to high thermal stress. The objective of the current study is to investigate the potential heat transfer enhancements in ventilated brake disk by varying the geometrical parameters of the blades inside the flow passage. This is done through comparisons of non-dimensional properties for flow and heat transfer in different blade configurations of the ventilated brake disk. The straight blade configuration is used as a baseline reference against the angled blades. The investigations are performed by using both experimental and computational means and the results are compared and discussed. Analysis shows that significant increase in braking performance can be achieved with relatively simple alteration of the ventilated blade angle. The results show a tremendous increase in the heat transfer rate with blade inclination angle configurations as compared to conventional straight blade. The Nusselt number is found to be in a power-law relationship with the Reynolds number. Distinct relationship between laminar and turbulent condition is predicted. An improvement in total convective heat transfer coefficient of 51% was achieved with blade inclination angle of 45° tilting towards clockwise direction.     

电磁制动与摩擦制动集成系统测试台架设计及试验研究

根据电磁制动与摩擦制动集成系统的工作原理,设计了一种电磁制动与摩擦制动集成系统测试台架.为检验该测试台架的性能.以某型轿车为对象.选择电磁制动器的磁极与制动盘间间隙、线圈匝数和磁极中心到制动盘中心距离为因素.进行3因素3水平正交试验.试验结果表明,采用所设计的测试台架对不同车型进行试验,可得到电磁制动与摩擦制动集成系统的最佳结构参数和安装参数.     

Improvement of Vehicle Dynamics by Rear Braking Force Control

A study on effective use of rear braking force to improve a brake performance and vehicle dynamics are carried out. On a ordinary condition, the rear braking force could be more increased to a conventional braking force distribution. Based on this thought, the brake performances are estimated. The results show the effects not only improve the brake performance but also reduce a pitching at braking and moderate a vehicle OS behavior in a turn during braking. These are verified by experimental test vehicle equipped with a rear braking force control system.     

用试验方法修正摩托车惯性试验台转动惯量

摩托车液动盘式制动器具有制动力矩大、制动灵敏性高、制动间隙自动调节、散热性好等优点,是现代新型摩托车普遍采用的制动器,同时也是重要的安全性能部件。台架试验是产品研制阶段的基础,也是摩托车制动器制劝性能必不可少的检测手段。摩托车制劝器惯性试验台是动态进行制动器性能测试的关键设备,对于这种精密试验检测设备,日常工作中一定要对其精度进行监控,各计量器具也要定期检查,尽可能降低检测设备的系统误差,这样才能保证试验工作的科学严谨性和检测数据的真实有效。     

Improvement of Vehicle Dynamics by Rear Braking Force Control

SUMMARY

A study on effective use of rear braking force to improve a brake performance and vehicle dynamics are carried out. On a ordinary condition, the rear braking force could be more increased to a conventional braking force distribution. Based on this thought, the brake performances are estimated. The results show the effects not only improve the brake performance but also reduce a pitching at braking and moderate a vehicle OS behavior in a turn during braking. These are verified by experimental test vehicle equipped with a rear braking force control system.     

某微型客车制动力分配优化设计

提出了M1类车辆空、满载制动力分配系数的计算公式.以理想制动力分配曲线与实际应用的两段不同斜率制动力分配线之间面积最小为优化目标,同时保证满载状况时的制动效率不小于75%,优化设计了某微型客车变比值的制动力分配曲线.考虑制动器推出压耗,建立了各轴制动力与管路液压的转化公式,由优化后的变比值制动力分配线确定了液压比例阀的特性曲线.对制动力分配曲线优化前、后的微型客车制动距离进行的对比计算表明,优化后的微型客车制动距离明显减小.     

多轴分布式电驱动车辆电液复合制动控制研究

针对多轴分布式电机驱动车辆电液复合制动中易出现的车辆制动抖动问题,提出了一种建压阶段电机制动力修正策略和一种基于前馈-反馈的协调控制策略,分别在建压阶段和其他阶段通过协调复合制动力来解决制动抖动的问题。针对防抱死控制系统与电机制动系统共同作用时的制动矛盾,提出了一种基于PID 控制的ABS控制策略,主要通过改变电机制动力来解决制动矛盾的问题。通过TruckSim、Matlab/Simulink及AMESim联合仿真验证,制动冲击度在建压阶段下降了 20.66%,在电机退出阶段下降了 92.59%,驾驶感觉得到明显改善。而 ABS控制策略也可在保证理想滑移率的同时完成制动能量回收;结合整车制动试验,表明协调控制策略在保证制动效果良好的同时实现了制动能量回收,效果显著。     

Co-operative control for regenerative braking and friction braking to increase energy recovery without wheel lock

This paper presents a regenerative braking co-operative control algorithm to increase energy recovery without wheel lock. Considering the magnitude of the braking force available between the tire and road surface, the control algorithm was designed for the regenerative braking force at the front wheel and friction braking force at the rear wheel to be increased following the friction coefficient line. The performance of the proposed regenerative braking co-operative control algorithm was evaluated by the hardware in the loop simulation (HILS) with an electronic wedge brake on its front wheels and an electronic mechanical brake on its rear wheels. The HILS results showed that a proper braking force on the front and rear wheels on a low μ road prevented the lock of the front wheels that was connected to the motor, and maintained the regenerative braking and increased energy recovery.     

面向制动噪声的盘式制动器零部件实模态分析

基于实模态分析理论和有限元法，研究了某盘式制动器的制动噪声问题，分别建立了制动盘、制动块、制动钳钳体和制动钳支架的有限元模型，计算了它们固有频率在20kHz以下的各阶实模态，并对与制动噪声有关的各阶模态进行了分析。     

一种制动试验台制动力检测系统的标定方法

FZD-9010B制动试验台为滚筒反力式制动试验台,是目前用于车辆制动性能检测的常规设备。基于虚拟仪器的FZD-9010B制动试验台检测系统可以实现制动力的动态、实时检测并可得制动过程的制动力曲线。针对于制动力检测系统的标定问题,笔者阐述一种有效的标定方法,通过设计一个杠杆机构,并借助标准砝码来实现的。该方法具有结构简单、有效、易于操作和实施的特点。     

制动衬片摩擦性能对轻型货车前后制动力之比的影响

本文研究了制动衬片摩擦性能——热衰退性能、速度和压力相关性对轻型货车鼓式制动器前后制动力之比的影响及其规律。研究表明,前后制动力之比不足一固定值,而是在很大范围内变化的一个区,从而影响同步附着系数,导致前后轮抱死区的变动;研究表明,摩擦特性受热不稳定而出现的逆衰退和过恢复是影响β的主要原因。本文还讨论了前后制动力之比β的简易计算法与台试实测结果间的差异,提出由制动器台架试验确定β之方法。     

Development of the brake system design program for a vehicle

It is quite challenging to estimate the braking performance of a vehicle because the brake system is comprised of many parts, including a booster, master cylinder, and caliper. Calculation of characteristics such as braking force through vehicle tests requires much time and money. Therefore, the development of a method to estimate the braking performance of a vehicle using qualitative methods is beneficial. In this study, a program that can analyze the braking capabilities of a vehicle such as pressure, efficiency, and pedal travel is presented. The increase in disc temperature during braking as well as the properties of various boosters can be calculated using the proposed program. Dynamic characteristics of a vehicle equipped with a Load Sensing Proportional Valve (LSPV) were computed more precisely by obtaining the change in valve pressure according to the displacement of a suspension system. Since all input and output files are composed in the Microsoft Excel format, both design data management and database construction can easily completed.