Browse Topic: Brake calipers

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A Novel Approach for the Frequency Shift of a Single Component Eigenmode through Mass Addition in the Context of Brake Squeal Reduction15-16-01-000409/23/2022
Abstract Brake squeal reduces comfort for the vehicle occupants, damages the reputation of the respective manufacturer, and can lead to financial losses due to cost-intensive repair measures. Mode coupling is mainly held responsible for brake squeal today. Two adjacent eigenfrequencies converge and coalesce due to a changing bifurcation parameter. Several approaches have been developed to suppress brake squeal through structural changes. The main objective is to increase the distance of coupling eigenfrequencies. This work proposes a novel approach to structural modifications and sizing optimization aiming for a start at shifting a single component eigenfrequency. Locations suitable for structural changes are derived such that surrounding modes do not significantly change under the modifications. The positions of modifications are determined through a novel sensitivity calculation of the eigenmode to be shifted in frequency. In the present work, the structural changes are carried out
Deutzer, Marcel, Stender, Merten, Tüpker, Nicolas, Hoffmann, Norbert
Methodology and application on load monitoring using strain-gauged bolts in brake calipers2022-01-112103/29/2022
As technology evolves, the number of sensors and available data on vehicles grow exponentially. In this context, it is essential to use sensors for monitoring key components, increasing safety and reliability, and gathering data useful for mechanical dimensioning and control systems. This paper presents an application of strain-gauged bolts brake calipers fixation of two electric vehicles. With this approach it was possible to obtain the loads applied to the brake pads and correlate them with braking behavior, therefore gaining insights on braking conditions and system state. The goal of the study is analyzing the strengths and limitations of the method and proposing developments to deploy it in real applications. This topic is particularly important and novel for electric vehicles, where powertrains can create positive and negative torques and generate complex interactions with braking system. Strain-gauges are a long-known technology applied in many fields, and its usage in bolts and
de Carvalho Pinheiro, Henrique, Sisca, Lorenzo, Carello, Massimiliana, Ferraris, Alessandro, Airale, Andrea Giancarlo, Falossi, Marco, Carlevaris, Alberto
Development of a Modeling Approach to Numerically Predict Filtration Efficiencies of Brake Dust Particle Filters2021-01-128510/11/2021
According to the European Environment Agency, air pollution is the biggest environmental health risk in Europe. Since traffic is one of the main contributors of fine dust, technical solutions are necessary to reduce the particulate emission footprint of vehicles. Also the Health Effects Institute hosted recently an international workshop on non-tailpipe emissions. Brake dust filtration concepts have proven to be a promising solution to significantly reduce fine dust emissions from brakes directly at the source. While CFD simulations for inner-ventilated brakes have become state-of-the-art, a holistic models from particle generation and emission to particle dynamics in the vicinity of the brake is not yet available. However, a good modeling approach of particle tracks is essential to predict filtration efficiencies of brake dust particle filters. It will be shown that based on current literature data and models, and independent of the turbulence model, filtration efficiencies cannot be
Keller, Florian, Krupa, Lukas, Beck, Andreas, Wörz, Tobias, Weller, Benedikt, Kohn, Kevin, Pfannkuch, Steffen, Jessberger, Thomas, Lehmann, Martin, Ashish, S
Analysis of the effect of the wedged type brake caliper piston on brake drag2021-01-129310/11/2021
Reducing brake drag has always been one of the most important goals among brake system engineers and its importance has never been higher due to the historic rise in global fuel economy and carbon emission standards. Although many studies have been done with regard to the improvement of brake drag, previous papers have focused mainly on studying the optimization of traditionally well-known factors such as geometry of the piston seal groove where the piston seal is to be located, piston materials, properties of the piston seal, and so forth. In contrast, only few papers deal with the entire mechanism of the piston roll-back. The present work tries to change the shape of the piston(wedged type) to differentiate the mechanism of the piston roll-back from the conventional method and attempts to illuminate the interaction between wedged type brake caliper piston and piston seal. Data from multi sources including several different dynamic drag tests and CAE analysis are presented and
Kim, Yooho, Kwon, Taiksang, Lee, Soonwook
Service Maintenance of SAE J1703 and SAE J1704 Brake Fluids in Motor Vehicle Brake SystemsJ1707_202106 (Current)06/10/2021
This SAE Recommended Practice provides basic recommendations for dispensing and handling of SAE J1703 and SAE J1704 Brake Fluids by Service Maintenance Personnel to assure their safe and effective performance when installed in or added to motor vehicle hydraulic brake actuating systems. This document is concerned only with brake fluid and those system parts in contact with it. It describes general maintenance procedures that constitute good practice and that should be employed to help assure a properly functioning brake system. Recommendations that promote safety are emphasized. Specific step-by-step service instructions for brake maintenance on individual makes or models are neither intended nor implied. For these, one should consult the vehicle manufacturer’s service brake maintenance procedures for the particular vehicle. Vehicle manufacturer’s recommendations should always be followed.
Brake Fluids Standards Committee
BMW reveals its first “M” performance-badged two-wheeler20AUTP11_1111/01/2020
BMW has revealed its first-ever M-badged motorcycle, the M 1000 RR superbike. A heavily reworked version of the already-capable S 1000 RR sportbike, the new machine is riding the trend of track-focused machines, as the motorcycle industry watches sportbike sales follow the same path as sedans in the automotive world. BMW's highly regarded Motorsports division produced its first racecar (the 3.0 CSL) in 1972 and its first road-going car with the mid-engine M1 in 1978. Since then, the Munich-based auto- and motorrad-maker has since produced an M version of nearly every car it has manufactured, the 7 Series being a notable exception.
Seredynski, Paul
Comparison of Particulate Matter and Number Emissions from a Floating and a Fixed Caliper Brake System of the Same Lining Formulation2020-01-163310/05/2020
The particulate emissions of two brake systems were characterized in a dilution tunnel optimized for PM10 measurements. The larger of them employed a fixed caliper (FXC) and the smaller one a floating caliper (FLC). Both used ECE brake pads of the same lining formulation. Measured properties included gravimetric PM2.5 and PM10, Particle Number (PN) concentrations of both untreated and thermally treated (according to exhaust PN regulation) particles using Condensation Particle Counters (CPCs) having 23 and 10 nm cut-off sizes, and an Optical Particle Sizer (OPS). The brakes were tested over a section (trip-10) novel test cycle developed from the database of the Worldwide harmonized Light-Duty vehicles Test Procedure (WLTP). A series of trip-10 tests were performed starting from unconditioned pads, to characterize the evolution of emissions until their stabilization. Selected tests were also performed over a short version of the Los Angeles City Cycle. PM2.5 emissions of burnished pads
Mamakos, Athanasios, Arndt, Michael, Hesse, David, Hamatschek, Christopher, Augsburg, Klaus
Topology Optimisation of Brake Caliper2020-01-162010/05/2020
The objective of the research is to develop a lightweight yet stiff, 2 piston fixed brake caliper which can be used in formula student race car. To make a race car, its components need to be lighter. To stop a car with minimum stopping distance, it needs to have a sophisticated braking system with well-designed components. The designing of the caliper is carried out on the Altair Inspire software. The topology optimisation algorithm is used to minimise the weight of the caliper without compromising the stiffness. The structural analysis is also carried out on the Altair Inspire. The caliper is also tested for fatigue failure using Ansys.
Ugemuge, Mosam, Das, Sreethul
Dimension Compatibility for Commercial Vehicle Wheels to Air Disc Brake Calipers - Truck and BusJ2803_202006 (Current)06/05/2020
This SAE Recommended Practice defines the boundary line for establishing dimensional compatibility between air disc brake calipers and 22.5 x 8.25 inch disc wheels, including bent valve stems on steel wheels and manufacturer recommended valve stems on aluminum wheels. The line establishes the minimum wheel with valve stem envelope to allow interchangeability. The line does not accommodate customer-specific wheels (such as OEM-specific stylized wheels) or customer-specific brakes. This document addresses dimensional characteristics only and makes no reference to the performance, operational dynamic deflections or heat dissipation of the system. It is up to the system integrator to ensure sufficient clearance exists between the caliper, wheel and valve stem to provide safe operating conditions. Mounting systems as noted are referenced in SAE J694.
Truck and Bus Wheel Committee
Influence of Pads and Brake Disc wear on Brake Squeal Noise2019-36-000501/13/2020
The present work aims to investigate the influence of wear of the pads and brake disc on the brake squeal behavior with the help of the Finite Element tool. Brake discs basically work by the pressure of the brake pads against a rotating disc. The friction between the pads and the disc causes the latter to decelerate, but it can also cause dynamic instabilities of the system giving rise to noises. Among the main noise in vehicle brake systems, there is the squeal noise, which is usually associated with the coupling of two neighboring natural modes. One possible way to identify unstable modes is by extracting complex eigenvalues from the system. An unstable mode can be identified when, in the result of the extraction of the complex eigenvalues, the real part of the eigenvalue is positive. In the present work, a brake system (disc and positioned pads and their respective materials and friction coefficients) was duly modeled and validated. The validation was done by means of a correlation
dos Anjos, Marco Túlio Batista, Gutiérrez, Juan Carlos Horta, Ferreto, Cláudio Junior, Silva, Felipe Dornellas, Donadon, Lázaro Valentin
Performance Gains of Load Sensing Brake Force Distribution in Motorcycles2019-28-242611/21/2019
Commercial motorcycles and scooters incorporate independent circuits for front and rear brake actuation, thus precluding load-dependent brake force distribution. In all cases of manual brake force modulation between the front and rear wheels, there is poor compensation for the changes in wheel loads on the account of longitudinal weight transfer, thus making it challenging to provide an adequate braking force to each wheel. The ratio in which the braking force should be distributed between the front and the rear wheels is dependent on the motorcycle’s geometry, weight distribution, mechanical sizing of braking system components, and is a variable based on the instantaneous deceleration. This connotes that a fixed bias of front and rear braking forces can be optimized only for a narrow range of motorcycle’s deceleration. Maximum braking performance occurs just prior to wheel lock-up, as a sliding tire provides less grip than a rolling tire. This is also the scenario when both the tires
Chakraborty, Apurva
Design and Testing of Custom Brake Caliper of a Formula Student Race Car2019-28-000710/11/2019
A Formula Student race car is a car designed and manufactured for speed, performance, and competition. For a car to have high speed and performance, their parts also need to be lighter with being able to sustain the dynamically occurring stresses. Effective braking is a crucial factor which determines the performance of the car. This paper focuses on designing a brake caliper on the basis of calculations done with respect to a Formula Student race car, selecting a material which is of low density but with higher strength which can be easily manufactured with low cost and analyzing the design. Further, the manufactured part is also tested statically to ensure proper working before being tested on an actual formula student race car. The caliper is again tested dynamically, where the caliper is mounted on rear wheels of the car. To ensure proper working, brake pressure sensors are being mounted which also helps to validate the calculations. The computer-aided design model is created in
Ugemuge, Mosam, Das, Sreethul
Squeal Noise Improvement by High Damping & High Stiffness under Layer Material2019-01-211109/15/2019
The purpose of this research is to clarify how damping characteristics of Under Layer (hereafter “UL”) material in the brake pads (hereafter “PAD”) influences brake squeal noise performance. In this study, UL material structure and dynamic viscoelasticity, for two different types of UL formulations are investigated. In addition, PAD damping ratio and squeal noise performance for multiple UL formulations are verified. As a result, the raw material orientation is determined based on manufacturing method, and it causes the UL material’s anisotropic properties. Dynamic viscoelasticity are dependent on the direction in which they are measured. In particular, the loss modulus, which is the damping element of dynamic viscoelasticity, is higher in the direction of the raw material orientation for the high damping and high stiffness UL formulation. In addition, it was confirmed that this loss modulus in the direction of the raw material orientation is effective for bending vibration. In the
Nishioka, Masato, Johnson, Leanne, Rosalez, Sean, Suzuki, Shusuke
Development of Parametrically Integrated Software Platform for Passenger Car Brake System2019-01-123104/02/2019
The hydraulic servo brake system for passenger car plays a central role in occupant protection, which directly affects the automotive active safety and road handling. In this paper, an integrated parameterized software platform of hydraulic servo brake systems is proposed to realize fast and efficient braking system development. At first, according to the structure and working principle of the hydraulic servo brake system, the relationship among amount of fluid required for brake caliper, pedal feel and performance of the brake system is analyzed. Then, based on kinematics and dynamics of the hydraulic servo brake system, a simulation model for analyze pedal feel and amount of fluid required for brake caliper is built in AMESim, which is composed of brake pedal, vacuum booster, brake master cylinder, brake hoses and brake calipers, etc. In addition, the accuracy of the simulation model is verified by bench tests, and the significantly influential factors on the amount of fluid required
Pan, Jin, Guo, Xuexun, Zhou, Wei, Pei, Xiaofei, Pan, Hao, Zhang, Jie
Effects of As-Cast Surface Conditions and Local Geometry on Plating Deposition2018-01-504511/14/2018
The inhomogeneity of casting microstructure can present many challenges to subsequent processing of castings such as electroplating. Specifically the surface microstructure and local topographic features have significant impact on the electroplating deposition thus the continuity of the plating films. The authors attempt to categorize the common casting surface microstructure features and correlate them to the electroplating characteristics such as conductivity and current density distribution, which in turn affect the plating deposition. Forming mechanisms of some of the most common casting surface microstructures that affect electroplating are discussed. Desirable casting surface microstructure for electroplating and the casting design and process practices to achieve it are proposed.
Huang, Yanjun, Ohta, Makoto, Pederson, Tara, Milligan, Orit (Baron)
Compressible Brake Fluid Turbulent Flow Simulation and Experimental Verification on Brake Bleeding Performance Improvements of an EPB Caliper2018-01-187610/05/2018
Brake bleeding is the process of removing air bubbles present on hydraulic brake systems from the master cylinder to the calipers of a vehicle, including the brake pipes and hoses. This is very important procedure affecting on brake performance, but still has been a key issue in automobile industry for last decades because reaching best bleeding performance has a limit that there is always remaining air in brake system. In this paper, it is reported on numerical and experimental investigations into the topic of bleeding performance improvements. Compressible brake fluid turbulent flow simulation with two-phase mixture model was performed to investigate the details of the bleeding performance drop during its cycles. The rig test of the hollow cylinder was carried out in order to secure the brake consumption amount curve whose results were used for the criterion of the parametric simulations using Tait equation to estimate the property of the brake fluid with the bulk modulus of 19,535
Mo, Jang-Oh
Experimental Investigation of Low-Frequency Vibration Patterns in Automotive Disk Brake Systems: Utilization Study for Modal Simulation Methods2018-01-151306/13/2018
Increasing demands on automotive comfort as well as diminishing vehicle noise levels draw new attention towards low-frequency vibration and noise issues of disk brake systems such as creep groan and moan. In view of this problem, the experimental investigation of relevant phenomena is within the scope of this article. The related experiments concerning two different setups have been performed at a drum driven suspension and brake test rig. Both assemblies consisted of a front axle corner including all parts of the integrated brake system. In order to gain understanding of characteristic triggering mechanisms and fundamental subsystem interactions, and moreover, to verify the suitability of modal methods for simulative evaluations of creep groan or moan, specifically elaborated Operating Deflection Shape (ODS) techniques have been applied. Via analyses of four different creep groan emergences, global stick-slip cycles between disk and pads are revealed. For two dissimilar vibrations in
Pürscher, Manuel, Huemer-Kals, Severin, Fischer, Peter
Q&A18AUTP01_1601/01/2018
Influences of Initial DTV on Thermomechnical Coupling in Disc Brake System2017-01-249209/17/2017
In this paper, the initial disc thickness variation (DTV) of a ventilated disc in automotive brake system is modeled as sinusoidal function of the second order. The transient thermomechanical coupling properties of the brake system is simulated using finite element (FE) modeling. The system models and results were verified by a thermomechanical coupling test of a disc brake conducted on a brake dynamometer. By using varied evaluation indexes such as the temperature distribution, the normal stress and the elastic deformation of disc surfaces, the influences of the initial DTV and its direction as well as its amplitude on the thermomechanical coupling characteristics were analyzed. The simulation results show that the distribution of temperature and the normal stress in circumferential direction exhibit the same sinusoidal function of the second order as the modeled initial DTV property, which is different from the thermomechanical coupling characteristics caused by disc surface initial
Meng, Dejian, Wang, Ziyi, Zhang, Lijun, Yu, Zhuoping
In-Plane and Out-of-Plane Vibrations of Brake Linings on the Rotor2017-01-253009/17/2017
The dynamics and, in particular, the NVH phenomena in brakes are still in the focus of research. Recent investigations of for example Rhee et al. show two principal vibrational forms of the linings on the rotor [1]. The first form is characterized by vibrations where both linings are in-phase (minimal differential torque between the inner pad and the outer pad). This produces in-plane vibrations of the rotor and results in high-frequency squealing events in the brake. The second form is an antiphase vibration of the brake linings with respect to each other (increased differential torque between the inner pad and the outer pad). This produce directly out-of-plane vibrational modes of the disc, which results in lower-frequency caliper and rotor oscillations. One hypothesis is that different wear densities of the linings essentially characterize the two vibrational modes. The wear behavior is not taken into consideration of this paper as it will be discussed in further publications. This
Ostermeyer, Georg Peter, Otto, Johannes, Rhee, Seong Kwan
Faster, Better, Economic - Newest Acid Zinc-Nickel Technology for Brake Caliper Plating2017-01-250709/17/2017
The demand for zinc-nickel coatings continuously increases in the automotive industry due to their high corrosion protection as well as superior wear and heat resistance compared to pure zinc platings. The state-of-the-art plating systems in the brake caliper industry are acid zinc-nickel electrolytes, as only they allow for direct plating on cast iron. Cast iron is the most common base material for the production of automotive brake components due to excellent mechanical and thermal properties. Well suited coatings will preserve the functional properties and provide additional advantages like improved corrosion protection and homogeneous and long lasting appearance. Consistently increasing quality demands, extended warranty periods and cost pressure lead to further developments and force the industry to look for new solutions. Therefore improvement of throwing power (thickness distribution) of acid zinc-nickel electrolytes would allow for a reduction in plating time and thus an
Hoch, Matthias, Kaczmarek, Michal, Ahr, Markus
Wear, Friction and NVH Characterization Using a Laboratory-Scale Tribometer2017-36-000305/24/2017
The current study presents some testing procedures which have been designed for friction and noise measurements of brake friction materials using a laboratory-scale tribometer. The uncertainties (errors) and precision of the measurements are also described in this paper. Some case studies related to friction, wear and noise related issues in brake friction materials were chosen to show the respective testing procedures. Through the error study, it was shown that the uncertainties of the lab. test bench are mainly associated with 3 variables: torque, force and sliding radius. The combined uncertainty of the friction measurements is less than or equal to ±1%, considering the typical operating range of the machine. The possibility of using two samples from a single brake pad also contributes to the reliability of the machine test and procedures. Finally, the laboratory-scale tribometer and testing procedures discussed in the present paper proved to be adequate to characterize friction
Pavlak, Rafael Paini, Neis, Patric Daniel, Poletto, Jean Carlos, de Barros, Liu Yesukai, Ferreira, Ney Francisco
Improved Impact Toughness and Heat Treatment for Cast AluminumTBMG-2570711/01/2016
NASA’s Marshall Space Flight Center researchers have developed a new, stronger aluminum alloy, ideal for cast aluminum products that have powder or paint-baked thermal coatings. With advanced mechanical properties, the NASA-427 alloy shows greater tensile strength and increased ductility, providing substantial improvement in impact toughness. In addition, this alloy improves the thermal coating process by decreasing the time required for heat treatment. With improvements in both strength and processing time, use of the alloy provides reduced materials and production costs, lower product weight, and better product performance. The superior properties of NASA-427 can benefit many industries, including automotive, where it is particularly well suited for use in aluminum wheels.
Vehicle Level Brake Drag Target Setting for EPA Fuel Economy Certification2016-01-192509/18/2016
The strong focus on reducing brake drag, driven by a historic ramp-up in global fuel economy and carbon emissions standards, has led to renewed research on brake caliper drag behaviors and how to measure them. However, with the increased knowledge of the range of drag behaviors that a caliper can exhibit comes a particularly vexing problem - how should this complex range of behaviors be represented in the overall road load of the vehicle? What conditions are encountered during coastdown and fuel economy testing, and how should brake drag be measured and represented in these conditions? With the Environmental Protection Agency (amongst other regulating agencies around the world) conducting audit testing, and the requirement that published road load values be repeatable within a specified range during these audits, the importance of answering these questions accurately is elevated. This paper studies these questions, and even offers methodology for addressing them. It includes a review
Antanaitis, David B.
Development of Advanced Braking System for Hybrid Sports Cars2016-01-192309/18/2016
An advanced braking system had to be developed for a next-generation hybrid sports car with Sport Hybrid Super Handling All-Wheel Drive to achieve an intuitive brake feeling in a variety of driving conditions, ultimate track performance and reduction of CO2 emissions per vehicle. This paper outlines the integration of brake-by-wire with traditional high-performance braking hardware and describes the technology needed to achieve these goals. Key focus areas to generate these results were: brake feeling control, corner hardware specification considerations and brake cooling.
Dyar, Lorne R., Akita, Yuichiro, Paul, Scott, Lepito, Joseph, Ishikawa, Yoshio, Watanabe, Tomohiro
Interactive Effects of Thermal Deformation and Wear on Lateral Runout and Thickness Variation of Brake Disc Rotors2016-01-193909/18/2016
Brake judder is one of the most serious problems in automotive-brake systems. It is basically a forced vibration caused by the friction-surface geometry of a brake disc, and therefore, disc rotors play a significant role in judder. There are two types of judder: cold and hot. Hot judder is caused by the thermo-mechanical deformation of a brake disc due to high-speed braking. There are several shapes of deformation, e.g., coning and circumferential waviness. Circumferential waviness is caused by thermo-mechanical buckling and typically found as a butterfly shape in a 2nd rotational-order and hot-spotting. In a previous paper, two groups of disc castings with different material homogeneity were machined intentionally to have two kinds of dimensional variations. From repetitive high-speed braking tests of these discs, both the material and dimensional homogeneity were found to affect the wave-like deformation of discs in the 1st and 2nd rotational-orders with different significance
Okamura, Toshikazu
Advanced Finishes for Brake Components and Other Castings2016-01-195109/18/2016
Caused by a number of beneficial properties inherently from the zinc-nickel material, this electrodeposited alloy is used more and more for cathodically protecting layers on ferrous components like cast iron brake calipers. Direct plating from acidic solutions is the state-of-the-art solution for zinc-nickel surface finishing of these components. To contribute to the continuous improvement of the final component and reduce the finishing cost, areas for improvement have been scrutinized in a current finishing system. Areas for improvement have been identified in the uniformity of the nickel distribution within different current densities and in the handling and economy of the metallic zinc anodes used for zinc metal replenishment. While today’s acidic zinc-nickel electrolytes suit and usually exceed the requirements for an alloy containing 10-15% nickel, nickel incorporation may drop just below 12% incorporation rate in areas which are plated at high current densities. Formation of
Dingwerth, Björn
Service Maintenance of SAE J1703 and J1704 Brake Fluids in Motor Vehicle Brake SystemsJ1707_201609 (Historical)09/13/2016
This SAE Recommended Practice provides basic recommendations for dispensing and handling of SAE J1703 and SAE J1704 Brake Fluids by Service Maintenance Personnel to assure their safe and effective performance when installed in or added to motor vehicle hydraulic brake actuating systems. This document is concerned only with brake fluid and those system parts in contact with it. It describes general maintenance procedures that constitute good practice and that should be employed to help assure a properly functioning brake system. Recommendations that promote safety are emphasized. Specific step-by-step service instructions for brake maintenance on individual makes or models are neither intended nor implied. For these, one should consult the vehicle manufacturer’s service brake maintenance procedures for the particular vehicle. Vehicle manufacturer’s recommendations should always be followed.
Brake Fluids Standards Committee
Configuration of Brake Components2015-01-266809/27/2015
The hydraulic brake products like brake calipers, master cylinders and boosters are the foundation of today complex vehicle brake systems. The state of the art application leads very often to an individual design, due to the fulfillment of customer requirements within the available installation space. Also the enormous pressure on cost and time require optimized design processes. Therefore Continental developed the product configuration software CoBra. Within this software tool, the engineering is able to react very fast on demands. Starting with the brake sizing parameters and the customer interface definition, CoBra supports the design engineer to select the necessary components and positioning them accordingly, considering the actual design standards. The data based configuration software collects all necessary design parameters and provides an export to parametric CAD start up models. Therefore a high level of data quality can be achieved which allows to couple further design and
Ungethuem, Ulrich, Simon, Dirk
A Study on the Bench Test of Friction-Induced Hot Spots in Disc Brake2015-01-269409/27/2015
During light to moderate braking at high speed, the local high temperature phenomenon can be observed on the brake disc surfaces, known as hot spots. The occurrence of hot spots will lead to negative effects such as brake performance fade, thermal judder and local wear, which seriously affect the performance of vehicle NVH. In this paper, based on the bench test of a ventilated disc brake, the basic characteristics of hot spots is obtained and the evolution process of temperature field and disc deformation is analyzed in detail. In temperature field, hot bands appear first and grow, migrate from inner and outer radius to the middle, with the growing temperature fluctuation and finally hot spots appear in the middle radius of the brake disc. The stable SRO waviness forms much earlier than the temperature fluctuation. In the stop brake studied in this paper, the SRO waviness stabilizes in main 7 order state which is lower than the final hot spot order. As the braking continuing, other
Ruan, Cheng, Zhang, Lijun, Meng, Dejian
Effect of Material and Dimensional Homogeneity on Thermo-mechanical Deformation of Brake Discs during High-speed Braking2015-01-267309/27/2015
Brake judder is one of the most serious problems in automotive-brake systems, and brake discs play a significant role in judder. There are two types of brake judder: cold and hot. Hot judder is caused by the thermo-mechanical deformation of a disc rotor due to high-speed braking. There are several causes and shapes of the deformation, e.g., coning and circumferential waviness. Circumferential waviness of brake discs is typically found as a butterfly shape in a 2nd rotational-order and corrugation (or hot-spotting) around a 10th order, which are caused by thermo-mechanical buckling. The author focused on the effects of material and dimensional homogeneity on the transient and permanent wave-like deformation of ventilated discs in low rotational-orders during repetitive high-speed braking. The tested discs were in two groups that had the same design and gray-cast-iron class but were cast in two foundries by using horizontal- and vertical-molding machines, respectively. Consequently the
Okamura, Toshikazu
Study of Development Technology of Brake Caliper Which Balances Preventing Squeal with Weight Reduction2015-01-268809/27/2015
It is well known that improving NV performance and weight saving are reciprocity. Brake squeal free is one of the top priority issues during development of brake system. To date, complex eigenvalue analysis has been utilized for prediction of brake squeal. It solves the structural instability problems by modal coupling which is the phenomenon that natural frequencies of normal modes are quite consistent. The positive real parts of complex eigenvalues are identified as instable vibration which causes brake squeal. On the other hand, the needs for light-weight brake system are higher than before due to recent trends of economizing fuel consumption and high driving performance. In order to obtain coexistence of brake squeal free with weight saving, shape optimization technique has been proposed for complex eigenvalue analysis. In this study, the real parts of eigenvalues are shifted to stable side analytically by optimization algorithm using response curved surface with minimizing mass of
Inoue, Hayuru, Hashimoto, Kumi, Kumemura, Yoichi
Brake Noise Prediction Using Altair Multi-Body Simulation2015-36-000205/13/2015
The level of noise transmitted to the passengers of a vehicle can drastically impact a passenger's comfort. Brake noise will give the customer an impression of poor product quality and can thus damage the quality image of the company. Within the automotive industry, the study of mode coupling instability by the use of FEM and modal complex analysis is widespread to reduce this phenomenon. In this paper an alternative method is presented, where potential brake noise issues are predicted by the use of a time transient integration using multi-body system analysis. The simulation model contains a nonlinear contact description, bushing, flexible bodies and the axis kinematics of the vehicle. Transient results are transformed by Fourier for a frequency domain study. The parameters that can be varied for the prediction analysis are brake pressure, vehicle speed, friction laws, system damping and bushing properties. The advantages of the multi-body system analysis approach are in the direct
Sundaresh, Keshav, Leila, Felipe Moretti
Proposed Metrological Method for Identifying Automotive Brake Discs2015-01-069104/14/2015
The main aim of this work is to develop an identification method to demonstrate the crucial surfaces of automotive braking system. Two brand new brake discs manufactured by two different manufacturers are tested. A typical disc to the one of them was put under working condition in actual braking system. Dimensional and geometrical deviations are investigated using advanced engineering metrological technique. Mechanical properties, tribological characteristics and chemical analyses are investigated. A coordinate measuring machine, universal hardness tester, mass comparator and XRF spectrometer are used in these diagnoses. Measurements of dimensional and geometrical deviations such as disc thickness variations, thickness deviations, straightness, parallelism, runout of disc surfaces are conducted. A comparison between form deviations in disc surfaces have been carried out and analyzed. The effect of material properties of the influencing surfaces on the wear rate and hardening of
Ali, Salah H. R., Zahwi, Sarwat Z. A., Dadoura, Hassan H.
Methodology for Sizing and Validating Life of Brake Pads Analytically2014-01-249509/28/2014
An area of brake system design that has remained continually resistant to objective, computer model based predictive design and has instead continued to rely on empirical methods and prior history, is that of sizing the brake pads to insure satisfactory service life of the friction material. Despite advances in CAE tools and methods, the ever-intensifying pressures of shortened vehicle development cycles, and the loss of prototype vehicle properties, there is still considerable effort devoted to vehicle-level testing on public roads using “customer-based” driving cycles to validate brake pad service life. Furthermore, there does not appear to be a firm, objective means of designing the required pad volume into the calipers early on - there is still much reliance on prior experience. This paper builds upon previous work by GM [1], where short duration, objective vehicle and dyno tests were combined with a computer model to allow for accurate pad service life prediction without vehicle
Antanaitis, David B., Lee, Heewook
Novel Mechanism Using Differential Gears for the Electromechanical Brake2014-01-038404/01/2014
As is well known, the brake systems of vehicles are used in order to decelerate or stop the vehicle while the driving. The operational principle of the brake is the conversion of kinetic energy into thermal energy. In this case, the thermal energy is released to the atmosphere. Recently, electromechanical brakes (EMB) were developed in order to replace hydraulic brake calipers. Such brake-by- wire systems are composed of an electronic pedal, electronic control unit (ECU), wire, and an electromechanical caliper. A typical electromechanical brake is similar to existing floating brakes. In other words, an inner pad pushes out one side of a disc driven by the energy of a motor; by means of a screw-thread gear. Then, the caliper slides in the opposite direction by reaction force and moves the outer pad toward the other side of the disc. Then pads clamp both sides of the rotating disc and stop the wheel. While effective, this design has the problem that there is a difference in the wear of
Park, Tae-Sang, Jin, Sungho, Moon, Jeon IL, Yang, Seung-Han
Characterization of Caliper Piston Material Stiffness and Damping2013-01-205009/30/2013
The brake caliper piston plays a key role in caliper function, taking significant responsibility for qualities such as fluid consumption, insulation of the brake fluid from heat, seal rollback function, and brake torque variation sensitivity to disc thickness variation. It operates in a strenuous environment, being routinely subjected to high stresses and elevated temperatures. Given all of the demands on this safety-critical component (strength, stiffness, wear resistance, stable friction against rubber, thermal stability, machinability, manageable thermal conductivity, and more), there are actually relatively few engineering materials suitable for use as a caliper piston, and designs tend to be limited to steel, aluminum, and engineered plastics (phenolic composites). The lattermost - phenolic composites - has been of especial interest recently due to mass savings and possible reduction in brake corner judder sensitivity to disc thickness variation. This paper focuses on
Antanaitis, David B., Riefe, Mark, Ciechoski, Chris, Flaim, Thomas, Greening, C
Regenerative Braking Control Enhancement for the Power Split Hybrid Architecture with the Utilization of Hardware-in-the-loop Simulations2013-01-146604/08/2013
This study presents the utilization of the hardware-in-the-loop (HIL) approach for regenerative braking (regen) control enhancement efforts for the power split hybrid vehicle architecture. The HIL stand used in this study includes a production brake control module along with the hydraulic brake system, constituted of an accelerator/brake pedal assembly, electric vacuum booster and pump, brake hydraulic circuit and four brake calipers. This work presents the validation of this HIL simulator with real vehicle data, during mild and heavy braking. Then by using the HIL approach, regen control is enhanced, specifically for two cases. The first case is the jerk in deceleration caused by the brake booster delay, during transitions from regen to friction braking. As an example, the case where the regen is ramped out at a low speed threshold, and the hydraulic braking ramped in, can be considered. During this transition, due to the communication delay and the delay associated with booster
Bayar, Kerem, McGee, Ryan, Yu, Hai, Crombez, Dale
Multi-Disciplinary Analyses for Brake Fluid Temperature Evaluation2013-01-063504/08/2013
During braking events, a brake corner sustains high brake torque, generating a large amount of heat in the process. This is most significant during mountain descent events and vehicle race track events. The brake thermal events not only reduce brake friction coefficient and lining life, but also produce elevated brake fluid temperature. Traditionally, brake hardware testing is warranted to evaluate brake fluid temperature for high speed flat track and mountain descent. These tests are costly and time-consuming. A CAE process to predict brake fluid temperature early in the vehicle development process before hardware exists, and to reduce and to replace testing will greatly benefit the vehicle development process. To this end, multiple analyses can be run. The heat transfer coefficients and cooling coefficients were evaluated from relevant CFD analyses. Then BrakePro and CarSim were run to evaluate appropriate brake flat track temperature profiles and simulated mountain schedule
Shi, Tinghui, Nisonger, Robert
Vehicle Integration Factors Affecting Brake Caliper Drag2012-01-183009/17/2012
Disc brakes operate with very close proximity of the brake pads and the brake rotor, with as little as a tenth of a millimeter of movement of the pads required to bring them into full contact with the rotor to generate braking torque. It is usual for a disc brake to operate with some amount of residual drag in the fully released state, signifying constant contact between the pads and the rotor. With this contact, every miniscule movement of the rotor pushes against the brake pads and changes the forces between them. Sustained loads on the brake corner, and maneuvers such as cornering, can both produce rotor movement relative to the caliper, which can push it steadily against one or both of the brake pads. This can greatly increase the residual force in the caliper, and increase drag. This dependence of drag behavior on the movement of the brake rotor creates some vehicle-dependent behavior. Major factors affecting rotor movement include wheel bearing stiffness, wheel radius, vehicle
Antanaitis, David B.
High Performance Corrosion Protection for Brake Components: Direct Zinc-Nickel Application and Post-Treatment2012-01-183109/17/2012
Cast-iron is a well suited material for manufacturing automotive brake components due to excellent mechanical and thermic properties. The application of a well chosen cathodically protecting coating adds durable appearance and preservation of the functional properties of the components. The selection of the right coating is driven by multiple factors of which economic considerations will always rank within the highest priorities next to protection performance and the appearance of the coating. Aiming for the highest possible performance in cathodic corrosion protection coatings leads directly to zinc-nickel coatings. Zinc-nickel coatings are already state-of-the-art in the finishing of mild steel and carburized steel materials in the automotive industry, mostly being plated from alkaline plating solutions. The application of alkaline solutions to cast iron material is not feasible under industrial conditions at an acceptable reject rate due the electrochemical properties of the cast
Dingwerth, Bjoern O.
Automotive Hydraulic Brake System - Metric Tube ConnectionsJ1290_201207 (Current)07/05/2012
This SAE Standard documents dimensional metric specifications for hydraulic brake system tubing with flared ends, threaded ports, and male tube nuts for the interconnection of major components in automotive hydraulic brake systems. The purpose of this document is to recommend preferred metrically dimensioned components (including alternative choices), that are intended to be functionally compatible with International Organization for Standardization Specification, ISO 4038. Some applications may require sizes of forms other than those shown herein, and this document does not preclude such other details when they are required.
Automotive Brake and Steering Hose Standards Comm
Materials for Plastic Pistons for Hydraulic Disc Brake CylindersJ1568_201204 (Current)04/30/2012
The materials defined by this SAE Standard are glass-fiber-reinforced, mineral-filled phenolic molding compounds suitable for compression molding. Preforms may be radio frequency preheated or screw preheated slugs. Compound for use in hydraulic disc brake caliper pistons.
Hydraulic Brake Components Standards Committee
Shelf Storage of Hydraulic Brake ComponentsJ1825_201204 (Current)04/30/2012
This SAE Information Report is the listing of recommendations for shelf storage for hydraulic brake components. Included in brake components are wheel cylinders, master cylinders, combination valves, and disc brake caliper assemblies. This document is not a specification. This document embodies the analyses and experiences of many users and manufacturers. Where specific manufacturers' recommendations are made, those recommendations shall supersede the recommendations of this document. This document lists the successful procedures and practices associated with brake components based on long experience of a wide cross section of manufacturers and users. The practices are expected to be applied to all brake components where SAE standards are applicable.
Hydraulic Brake Components Standards Committee
Simulative Investigation of Wheel Brakes in Terms of the Anchor Load and Pad Movement2011-01-238309/18/2011
In the research project between the Institute of Automotive Engineering (FZD) of the Technische Universität Darmstadt (TUD) and Continental Teves AG & Co. oHG a new modeling concept has been developed. With the aim to enhance the current development process, the brake caliper is modeled based on coupled rigid bodies integrated into a nonlinear system model. Using an explicit interface definition, the number of degrees of freedom is minimized and the calculation of caliper performance is possible over a wide range of parameters. Compared to models based on the Finite Element Method (FEM), fully parameterized geometry from CAD is not necessary, thus the caliper can be optimized for a variation of its geometrical and physical parameters. With this modeling approach, typical performance criteria such as caliper fluid displacement, hysteresis, uneven pad wear and residual torque can be calculated in a virtual bench test. Additionally, the pull-push-characteristic and the tendency towards
Haag, Mathias, Fan, Junli, Winner, Hermann, Ungethuem, Ulrich, Simon, Dirk
Evaluation of AL 2 O 3 , Graphite and Sulphide Effects on MU Behavior in Different Humidity Environments Through Combined Mixture-Environmental DOE2011-01-234909/18/2011
The friction performance of a Disc Brake Pad is even more required to present stable mu behavior in various environmental conditions such as different temperature and humidity. Interaction between compositional variables (raw materials) and environmental conditions cannot be revealed by a simplistic approach without taking into account their mutual interactions. Thereby is necessary a "crossed" design able to combine mixture components with environmental factors. This paper reports the mu behavior of a commercial Brake Pad Formulation in two different environmental conditions (winter condition, e.g., low humidity, and summer condition, e.g., high humidity) through a Combined Design of Experiment. The design was defined by the variation of three mixture components (Al₂O₃, Graphite and Sulfides) of the Brake Pad Formula according to a Response Surface Method (RSM). The μ behavior has been evaluated on a full-scale dynamometric bench test (AK-Master) with climatic control. The DoE output
Merlo, Fabrizio, Passarelli, Umberto, Buonfico, Pietro
Measuring System Approach to Analyze Brake Squeal Triggering Mechanism2011-01-235909/18/2011
There are several different possibilities to analyze a squealing brake system. The present paper introduces a complex measuring system which is mounted on a complete vehicle axle at a test rig. This system was developed because the previously performed state-of-the-art tests did not allow any insights in the squeal triggering mechanisms. First of all, a frequency analysis was performed. Thereby the main vibrating parts and the directions of the oscillation could be determined during a squeal event. The second was a modal analysis of the vehicle axle, which was necessary to get further insights into the system as well as to verify an existing Finite Element Method model. Through these tests, however, it was not possible to get any insight into the contact area, and therefore it was impossible to determine the squeal triggering mechanism. Because of this limitation, special guide pins were developed, which are able to measure the vibrating friction force. Strain gauges allow this
Wallner, Daniel, Bernsteiner, Stefan
Brake Drag Fundamentals2011-01-237709/18/2011
Control of brake drag is an important disc brake corner OEM requirement to minimize brake judder, friction material temperatures and fuel consumption. Brake calipers usually include clearances between the pads and rotor during brakes-off running conditions, allowing the pads to be knocked clear of the rotor; therefore minimizing drag. The present paper describes test methods to validate caliper designs, data analysis techniques to diagnose drag problems and data sets with worked examples. The present study summarizes the results of over 300 dynamic drag tests incorporating 60 separate test samples. The test samples share the same vehicle platform design; however three variations of Standard production design, Standard production design plus a pad spreader shim and a design with increased retraction are included. The effect of these design variations on drag is presented, whilst the effect of adding an adhesive to a pad back plate is also indicated. A most significant observation was
Backstrom, Alan
Diagnosis of Off-Brake Performance Issues with Low Range Pressure Distribution Sensors2010-01-007304/12/2010
Brake caliper and corner behavior in the off-brake condition can lead, at times, to brake system performance issues such as residual drag (and related issues such as pulsation, judder, and loss of fuel economy), and caliper pryback during aggressive driving maneuvers. The dynamics in the brake corner can be strikingly complex, with numerous friction interfaces, rubber component and grease dynamics, deflections of multiple components, and significant dependence on usage conditions. Displacements of moving parts are usually small, and the residual forces in the caliper interfaces involved are also small in comparison with other forces acting on the same components, making direct observation very difficult. The present work attempts to illuminate off-brake behavior in two different conditions - residual drag and pryback - through the use of low-range pressure distribution sensors placed in between the caliper (pistons and fingers) and the brake pad pressure plates. Data from multiple
Antanaitis, David B.
Phenomenological Approach to the Automotive Disc-Scoring Phenomena Related to Metal Pick Up Generation on Brake Pad Surface2009-01-302110/11/2009
This study investigates two evidences we observe from the field about metal pick up (MPU) generation on passenger car disc brake pads. The first evidence is that Low-steel (LS) materials usually present MPU issues in wet conditions whereas NAO materials mainly give MPU in dry conditions. A deep energy dispersive X- ray fluorescence (XRF) analysis is performed on LS brake pad surface after wet and dry MPU car testing, while a DoE on NAO material is carried out in order to investigate the effects of some compound on dry MPU generation. On the basis of our results, and according to previous literature works, dry and wet MPUs generation mechanisms are proposed. The second evidence is that some rotors are more prone to MPU generation than others. Vehicle and dyno MPU generation tests have been performed on different rotors using the same brake pad material: a first microstructural analysis of the rotors is reported.
Passarelli, Umberto Paolo, Durando, Pietro, Buonfico, Pietro
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