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In this paper an effective technology of virtual thermal test of disc brake with several advanced analytic techniques was presented. With the virtual thermal test process, thermal performance of brake system could be easily evaluated without any possibility of great errors that used to happen in the past. In addition to the classical result of CFD, this virtual thermal test produced several valuable applications such as thermal deformation of rotor, optimization of thermal performance and estimation of braking distance.

In spite of many squeal noise studies, it is still hard to predict squeal noise these days. Squeal analysis is a useful technique in reducing or removing squeal noise. As a result, several papers that contain reasonable finite element model with correlation, squeal mode analysis, and design proposals that can reduce the squeal noise have been released. In this paper, Generalized Frictional Stiffness Matrix was extracted using Generalized Coordinate in ABAQUS. GFSM(Generalized Frictional Stiffness Matrix) is an unsymmetrical matrix which creates a real-eigen-value (unstable mode) in complex eigenvalue problem. Then, sensitivity of each term in GFSM is calculated. The least modification was proposed from the sensitivities to reduce the squeal noise. To verify this proposal, a reasonable finite element model was generated by correlating component and assembly modal tests.

There have been many kinds of simplifications and limitations in evaluating the thermal performance of disc brake when using the analytic technologies which were established before. But now new technology of virtual test with several advanced analytic techniques was developed to evaluate the thermal performance without any possibility of great errors that used to happen for the earlier time-consuming analyses. As a result, it was estimated that the new virtual test technology could afford to replace the physical dynamo test since the reliability of virtual test technology was reasonably verified with the existing data measured in dynamo test.

ABS assembly is supported by the mounting bracket which is installed at the body inside engine room. Such feature of the mounting bracket requires consideration of durability performance under the dynamic random loads imposed by engine excitation. So, modal parameters, such as natural frequencies and mode shapes, of ABS assembly and its bracket should be considered when evaluating the fatigue life. Therefore, fatigue analyses and experiments of ABS assembly and its bracket were performed in the frequency domain rather than the time domain. After that, analysis results were compared and correlated with experimental results, and the analysis method was updated to improve analysis accuracy.

An Electrical Parking Brake (EPB) system is a device that operates to park the vehicle automatically with the push of a button instead of using conventional hand or foot levers which in some ways makes it the first by wire type of brake system. As such, it is being considered in some vehicle architectures as an automatic redundant backup for vacuum-less brake systems or autonomous cars. The EPB system is generally divided into cable puller and motor on caliper (MOC) types. Recently, the MOC type EPB is being more widely applied in the global market due to product competitiveness and cost effectiveness. The MOC type EPB is composed of the caliper body, torque member, pad assembly, nut assembly and actuator. Among them, the caliper body and torque member play a main role in the robustness of the EPB system and occupy more than 80% of the total weight.

It is widely believed or speculated that higher pad compressibility leads to reduced brake squeal and that caliper design can affect brake squeal. After encountering anecdotal contradictory cases, this investigation was undertaken to systematically generate basic data and clarify the beliefs or speculations. In order to adjust pad compressibility, it is common to modify pad molding temperatures, pressures and times, which in addition to changing the compressibility, changes friction coefficient and physical properties of the pad at the same time. In order to separate these two effects, NAO disc pads were prepared under the same molding conditions while using different thicknesses of the underlayer to achieve different compressibilities, thus changing the compressibility only without changing the friction coefficient and physical properties of the pad.

Nowadays, brake squeal noise is one of the most difficult problems and is a big issue in the automobile industry. Finite element analysis is a useful tool in predicting the noise occurrence of a conventional brake system during the design stage. This paper explains the technical procedure and method to resolve the squeal noise with commercial software programs. Friction coefficient under the operating conditions of the brake system was considered as a variable with respect to disc velocity and there was a dynamic behavior within the pad assembly during brake action. First of all, our Finite Element (FE) model was verified using the results of the parts and assembly's FRF measurements and an inertia noise dynamometer, followed by complex eingen value analysis to detect unstable frequencies. Subsequently, mode analysis was conducted for each part of the brake system through the MAC values.

The effects of pad properties and thermal coning of discs on high speed judder were investigated using dynamometer and vehicle tests. The friction materials of different thermal conductivities were manufactured and the discs were design-modified to control the thermal coning during braking under high speed conditions. Brake Torque Variation(BTV) was measured to evaluate the judder propensity in the dynamometer tests and the vibration on steering wheel and brake pedal was measured in the vehicle tests. The results showed that the increase of thermal conductivity of pad could not affect the judder propensity during high speed braking below 350°C of disc temperature, however better disc design reduced judder propensity due to the lower thermal deformation. Moreover, the increase of pad compressibility can reduce judder propensity due to the increase of damping capacity.

The history of the brake system for the passenger vehicles is no shorter than that of the automobile itself. With the long history, its performance, efficiency and reliability have been dramatically improved and as a result, even leading brake system suppliers now find it very difficult to come up with breakthrough ideas for further optimization of the current brake systems. In addition, as the powertrain of the vehicles has also been improved, the requirements of the brake system have become much more severe than before, leading to a trend of increasing the system size and weight especially for the parts belong to unsprung mass. In the case of high-end vehicles, the system was further optimized using expensive materials such as ceramic, carbon-fiber, etc. However, most normal vehicles have been developed without any significant changes in the existing systems. This decade-long trend of developing braking parts has seen a big change “electrification of the vehicle”.

Corrosion stiction at the contact interface between a brake friction material and a gray iron disc under the parking brake condition was investigated by evaluating the possible parameters that affect the shear force to detach the corroded interface. Using production brake friction materials, comprising non-steel and low-steel types, corrosion tests were carried out by pressing the brake pad onto the gray iron disc using a clamp at various conditions. Results showed that the shear force to detach the corroded interface tended to increase with applied pressure and corrosion time. On the other hand, porosity, acidity, and hydrophobicity of the friction material did not show a reliable correlation to the stiction force. The poor correlation of the stiction force with the friction material properties indicated that the stiction force was not determined by a single factor but governed by multiple parameters including surface contact areas and inhomogeneity of the ingredients.

EMB (Electro-Mechanical Brake) which converts electrical motor power to brake clamping force at each wheel is a system that has been investigated and developed by various automotive part suppliers through the years. In particular, as the number of electrically powered vehicles, such as hybrid electric vehicles, electric vehicles and fuel cell electric vehicles, has expanded, the EMB has received increased interest due to its fast response that is much suited for effective cooperative control with regenerative braking. However, issues such as cost competitiveness, reliability and regulations need to be solved for commercialization [1-2]. A new concept, the hybrid Electro-Mechanical Brake (hEMB) is characterized by a dual piston structure linked by hydraulics inside of the caliper. It is possible to reduce the required motor power and increase the level of emergency back-up braking through the amplification effect of the dual piston mechanism [3].

Recently, there’s a massive flow of change in the automotive industry with the coming era of electric vehicles and self-driving (autonomous) vehicles. The automotive braking system field is not an exception for the change and there are not only lots of new systems being developed but also demands for researches for optimizations of conventional brake systems fitting to the newly appeared systems such as E-Booster and Electric Motor Brake (EMB) Caliper. Taking the Electric Motor Brake Caliper for example, it is considered as a very important and useful system for autonomous vehicles because the motor actuator of the caliper is much easier to control with ECUs compared to the conventional hydraulic pressure system. However, easy of control is not the only thing that excites brake system engineers.

The development trend of new vehicles is to shorten the development period, diversify the models, and produce small amounts compared to the past. The current development process of braking systems is difficult to meet recent development trends, and it is more difficult to shorten the development period in the verification process that requires actual products. In this paper, we developed a 1-D Simulation of AMESim, MATLAB/Simulink Co-Simulation model of Hyundai Mobis iMEB(Integrated Mobis Electronic Brake) system for eco-friendly vehicles. If hydraulic braking is applied more than the tire grip force during braking, tire slip occurs, and if the rear wheel is locked before the front wheel, stability is lost, so it is advantageous to decide design parameter of brake system to make the front wheel first locked in consideration of design parameters of each vehicle.

The current braking system of a vehicle includes a parking braking system, which consists of a Motor on Caliper (MOC) that generates hydraulic main braking and electric parking braking through a caliper structure. When designing the MOC braking system, it is important to consider an analytical model that can predict the performance of the parking clamping force and the torque generated between the disk and caliper interactions. However, in previous designs, system predictions were often based on simplified structural calculations or incomplete Finite Element Method (FEM) analysis. In this paper, a study was conducted to predict the system performance using Multi-flexible Body Dynamics (MFBD) analysis. Firstly, a kinematic model (MBD) was developed for the Electric Parking Brake (EPB) system currently used in mass-produced vehicles. And the MBD model which based on kinematics was the initial model for this study.

When two identical brakes are simultaneously tested on a vehicle chassis dynamometer, very often the left hand brake is found to squeal more or less than the right hand brake, all at different frequencies. This study was performed to develop some understanding of this puzzling phenomenon. It is found that as the wear rate difference between the inner pad and the outer pad increases, low frequency (caliper and knuckle) squeals occur more and more, and as the differential wear becomes larger and larger, high frequency (disc) squeals occur less and less, finally disappearing all together. Discs and calipers are found to affect the differential pad wear, in turn affecting brake squeal generation.