Browse Topic: Brake components

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Verifying large alternate product code for an Joint Aerospace/Ground Vehicle Document document - JAGV01JAGV00000000000000000000000000001_202511 (Current)11/24/2025
Verifying large alternate product code for an Joint Aerospace/Ground Vehicle Document document - JAGV01
Active Safety Systems Standards Committee
Motor Vehicle Brake FluidJ1703_202511 (Historical)11/21/2025
This SAE Standard covers motor vehicle brake fluids of the nonpetroleum type, based upon glycols, glycolethers, and appropriate inhibitors, for use in the braking system of any motor vehicle such as a passenger car, truck, bus, or trailer. These fluids are not intended for use under arctic conditions. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM).
Brake Fluids Standards Committee
Hot Impulse Test for Hydraulic Brake Hose AssembliesJ1833_202510 (Current)10/13/2025
test
Automotive Brake and Steering Hose Standards Comm
A Novel Approach for the Frequency Shift of a Single Component Eigenmode through Mass Addition in the Context of Brake Squeal Reduction15-16-01-00049/23/2022
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 on a beam and a brake caliper. Selected eigenfrequencies are shifted while the frequencies of the other eigenmodes are simultaneously fixed. Experimental investigations for the brake caliper validate the numerical findings and the applicability as well as efficiency of the proposed methods.
Deutzer, Marcel, Stender, Merten, Tüpker, Nicolas, Hoffmann, Norbert
External Automatic Slack Adjuster Performance RequirementsJ1513_202111 (Current)11/3/2021
The performance requirements have been established for external automatic slack adjusters when tested to SAE J1462.
Truck and Bus Foundation Brake Committee
Driveline Parking Brake Test Procedure for Medium Duty VehiclesJ2690_202110 (Current)10/28/2021
This SAE Recommended Practice establishes uniform test procedures for friction based parking brake components used in conjunction with hydraulic service braked vehicles with a gross vehicle weight rating greater than 4500 kg (10 000 lb). The components covered in this document are the primary actuation and the foundation park brake. Various peripheral devices such as application dashboard switches or indicators are not included. These test procedures include the following: a Brake Related Tests 1 Brake Functional Performance 2 Brake Dynamic Torque Performance 3 Brake Corrosion Resistance 4 Brake Endurance with Torque 5 Brake Endurance without Torque 6 Vibration Resistance 7 Brake Ultimate Static Load 8 Brake Lining Wear Adjuster Function b Actuation Related Tests 1 Mechanical Actuator Functional Performance 2 Mechanical Actuator Endurance 3 Mechanical Actuator Quick Release 4 Mechanical Actuator Ultimate Load 5 Spring Apply Actuator Functional Performance 6 Spring Apply Actuator Operating Temperature Range 7 Spring Apply Actuator Endurance 8 Spring Apply Actuator Corrosion Resistance 9 Spring Apply Actuator On-Off Switch 10 Spring Apply Actuator Vibration
Truck and Bus Hydraulic Brake Committee
Brake Lining Quality Test ProcedureJ661_202110 (Current)10/26/2021
The purpose of this SAE Recommended Practice is to establish a uniform laboratory procedure for securing and reporting the friction and wear characteristics of brake linings. The performance data obtained can be used for in-plant quality control by brake lining manufacturers and for the quality assessment of incoming shipments by the purchasers of brake linings.
Brake Linings Standards Committee
Service Maintenance of SAE J1703 and SAE J1704 Brake Fluids in Motor Vehicle Brake SystemsJ1707_202106 (Current)6/10/2021
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
Automotive Air Brake Line Couplers (Gladhands)J318_202106 (Current)6/10/2021
This SAE Recommended Practice is intended to provide design, interchangeable dimensions, testing procedures, performance requirements, and minimum identification for gladhand-type air line couplers used to connect the brake systems of trucks, truck-tractors, trailers, and dollies when these vehicles are joined to operate as a combination unit.
Truck and Bus Brake Supply and Control Components Committee
Low Water Tolerant Brake FluidsJ1705_202105 (Current)5/28/2021
This SAE Recommended Practice was prepared to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance requirements in order to assess the suitability of silicone and other low water tolerant type brake fluids (LWTFs) for use in motor vehicle brake systems. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM). In the development of the recommended requirements and test procedures contained herein, it is concluded that the LWTFs must be functionally compatible with braking systems designed for SAE J1703 and SAE J1704 fluids. To utilize LWTFs to the fullest advantage, they should not be mixed with other brake fluids. Inadvertent mixtures of LWTFs with fluids meeting SAE J1703 are not known to have any adverse effects on performance, but not all combinations have been tested. Vehicle manufacturer’s recommendations should be followed where indicated. These fluids are not necessarily suitable for use in central hydraulic or pumped systems and are not intended for use below temperatures of -50 °C (-58 °F). Brake fluids covered under this document are not required to tolerate water and extreme caution should be exercised to prevent accidental entry of water which might lead to brake failure. Other performance characteristics of these LWTFs not covered in this document are discussed in Appendix A.
Brake Fluids Standards Committee
Disc Wheel and Hub or Drum Interface Dimensions - Truck and BusJ694_202104 (Current)4/30/2021
This SAE Recommended Practice contains dimensions and their tolerances concerning disc wheel to hub or drum interface areas for truck and bus applications. Disc wheels designed only for single wheel applications (not dual wheels) for light trucks and special or less common applications are not covered in this document.
Truck and Bus Wheel Committee
Test Procedures for Non-SAE Hydraulic HosesJ2545_202104 (Current)4/14/2021
This SAE Recommended Practice identifies test procedures and parameters which may be used to evaluate, qualify and inspect non-SAE hydraulic hoses or other hose constructions which do not conform to any established ISO or national standards defining hydraulic hoses. (Non-SAE hydraulic hoses are defined as those which do not conform to the categories listed in SAE J517.) It is not intended for evaluating fluoropolymer lined hose constructions or hose constructions with working pressures above 86 MPa.
Hydraulic Hose and Hose Fittings Committee
Snowmobile Service Brake SystemJ44_202103 (Current)3/16/2021
This SAE Standard establishes a uniform testing procedure and performance requirements for the level surface testing of hand-operated service brake systems on snowmobiles.
Snowmobile Technical Committee
Graphic Symbols for Aircraft Hydraulic and Pneumatic SystemsAS1290C (Current)2/12/2021
This SAE Aerospace Standard (AS) provides a system of graphic symbols and line codings that are intended primarily for usage in hydraulic and pneumatic system schematic diagrams for all types of aircraft.
A-6 Aerospace Actuation, Control and Fluid Power Systems
Validation of Compressibility Test Systems for Friction MaterialsJ3079/1_202101 (Current)1/13/2021
This SAE Recommended Practice (RP) applies to the validation process for test systems used to measure deflection (compressibility, creep, or swell and growth) of friction materials and friction material assemblies. The materials or assemblies can fit passenger cars, light trucks, and commercial vehicles equipped with hydraulic or air brake systems, using disc or drum brakes.
Brake Linings Standards Committee
Dimensional Compatibility for Commercial Vehicles Fitment of Complete Wheels in Drum Brake Applications - Truck and BusJ1865_202011 (Current)11/4/2020
This SAE Recommended Practice defines a clearance line for establishing dimensional compatibility between drum brakes and wheels with 19.5 inch, 22.5 inch, and 24.5 inch diameter rims. Wheels designed for use with drum brakes may not be suitable for disc brake applications. The lines provided establish the maximum envelope for brakes, including all clearances, and minimum envelope for complete wheels to allow for interchangeability. This document addresses the dimensional characteristics only, and makes no reference to the performance, operational dynamic deflections, or heat dissipation of the system. Valve clearances have not been included in the fitment lines. Bent valves may be required to clear brake drums. Disc brake applications may require additional running clearances beyond those provided by the minimum contour lines. Mounting systems as noted are referenced in SAE J694.
Truck and Bus Wheel Committee
Air Brake Performance and Wear Test Code Commercial Vehicle Inertia DynamometerJ2115_202008 (Current)8/20/2020
This SAE Standard provides test procedures for air and air-over-hydraulic disc or drum brakes used for on-highway commercial vehicles over 4536 kg (10000 pounds) GVWR. This recommended practice includes the pass/fail criteria of Federal Motor Vehicle Safety Standard No. TP-121D-01.
Truck and Bus Foundation Brake Committee
Truck and Bus Grade Parking Performance Test ProcedureJ360_202008 (Historical)8/19/2020
This SAE Recommended Practice establishes methods to determine grade parking performance with respect to: a. Ability of the parking brake system to lock the braked wheels. b. The vehicle holding or sliding on the grade, fully loaded or unloaded. c. Applied manual effort. d. Unburnished or burnished brake lining friction conditions. e. Down and up grade directions.
Truck and Bus Brake Systems Committee
Measurement of Copper and Other Elements in Brake Friction MaterialsJ2975_202007 (Current)7/23/2020
This procedure describes a method for generating, preparing and analyzing samples of new and unused brake friction materials for their chemical constituents.
Brake Linings Standards Committee
Dimension Compatibility for Commercial Vehicle Wheels to Air Disc Brake Calipers - Truck and BusJ2803_202006 (Current)6/5/2020
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
Low-Duty Inertia Dynamometer Hydraulic Brake Wear Test Procedures for Vehicles Above 4536 kg (10000 pounds) of GVWRJ3006_202005 (Current)5/26/2020
This Recommended Practice is derived from OEM and tier-1 laboratory tests and applies to two-axle multipurpose passenger vehicles, or trucks with a GVWR above 4536 kg (10 000 pounds) equipped with hydraulic disc or drum service brakes. Before conducting testing for a specific brake sizes or under specific test conditions, review, agree upon, and document with the test requestor any deviations from the test procedure. Also, the applicable criteria for the final test results and wear rates deemed as significantly different require definition, assessment, and proper documentation; especially as this will determine whether or not Method B testing is needed. This Recommended Practice does not evaluate or quantify other brake system characteristics such as performance, noise, judder, ABS performance, or braking under extreme temperatures or speeds. Minimum performance requirements are not part of this recommended practice. Consistency and margin of pass/fail of the minimum requirements related to wear rates and wear behavior can be assessed as part of the project in coordination with the test requestor. NOTE: This Recommended Practice uses the unit conversion and rounding techniques from the NIST Special Publication 811. This to ensure the use of standard conversion factors and to determine the appropriate number of significant digits to ensure the Rounding Error (RE) of the converted unit is smaller than or similar to the RE of the original English or Imperial unit.
Truck and Bus Hydraulic Brake Committee
Research on Compensation Redundancy Control for Basic Force Boosting Failure of Electro-Booster Brake System2020-01-02164/14/2020
As a new brake-by-wire solution, the electro-booster (Ebooster) brake system can work with the electronic stability program (ESP) equipped in the real vehicle to realize various excellent functions such as basic force boosting (BFB), active braking and energy recovery, which is promoting the development of smart vehicles. Among them, the BFB is the function of Ebooster's servo force to assist the driver's brake pedal force establishing high-intensity braking pressure. After the BFB function failure of the Ebooster, it was not possible to provide sufficient brake pressure for the driver's normal braking, and eventually led to traffic accidents. In this paper, a compensation redundancy control strategy based on ESP is proposed for the BFB failure of the self-designed Ebooster. Firstly, introduced the working principle of Ebooster and ESP, and a suitable pressure-building circuit was selected for the dual brake actuator system; Secondly, after the BFB failure of Ebooster, the rule-based strategy of braking awareness recognition was designed. Thirdly, a layered closed-loop compensation control strategy is designed based on the ESP to restore the pressure building capacity of the hydraulic system. Finally, based on dSPACE products, a hardware-in-the-loop (HiL) experimental bench with dual brake actuators including ESP and Ebooster was built for algorithm verification. The HiL experiment results show that after the BFB failure of Ebooster, the designed compensation redundancy control algorithm can restore the Pressure-Volume (P-V) characteristics of the brake system just like Ebooster's conventional BFB mode, and improve vehicle driving safety.
Zhao, Jian, Chen, Zhicheng, Zhu, Bing, Wu, Jian
Model-Based Brake Disc Temperature Prediction on High Speed Testing Mode and Circuit2020-01-02144/14/2020
A brake is a mechanical device that inhibits the motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by friction energy. Commonly, most brakes use friction between two surfaces pressed together to convert the kinetic energy of the moving object into heat, though other methods of energy conversion may be employed. If braking is repeated or sustained in high load or high-speed conditions, the motion will be unstable and can lead to a loss of stopping power because the disc capability for braking is not enough. These phenomena are generally defined as brake fading. Brake fade is caused by an overheating brake system. This paper describes the thermal modeling and process to predict the disk temperature under a condition which causes the fade characteristics. Also, the model of disc temperature prediction developed with consideration of acceleration and deceleration from the vehicle specification by combining the full vehicle modeling with thermal disc model. The disc temperature model is a highly reliable model because it is correlated with measurement data and based on this correlated thermal model, it can be predicted the brake disc geometrical parameters according to the specification change of the vehicles in the concept stage before the prototype development.
Jeong, PilYoung, Lee, Jaekil, Oswald, Mario, Kellner, Stefan
Simulation of Curved Road Collision Prevention Warning System of Automobile Based on V2X2020-01-07074/14/2020
The high popularity of automobiles has led to frequent collisions. According to the latest statistics of the United Nations, about 1.25 million people worldwide die from road traffic accidents each year. In order to improve the safety of vehicles in driving, the active safety system has become a research hotspot of various car companies and research institutions around the world. Among them, the more mature and popular active security system are Forward Collision Warning(FCW) and Autonomous Emergency Braking(AEB). However, the current active safety system is based on traditional sensors such as radar and camera. Therefore, the system itself has many limitations due to the shortage of traditional sensors. Compared to traditional sensors, Vehicle to Everything (V2X) technology has the advantages of richer vehicle parameter information, no perceived blind spots, dynamic prediction of dangerous vehicle status, and no occlusion restriction. In order to overcome the many shortcomings of the existing anti-collision warning system and strategy, this paper proposes a curved road collision prevention warning strategy based on V2X technology. Through V2X technology, the state information released by the neighboring car and the road environment information issued by the roadside unit are obtained. Using the above information and the state information of the vehicle, the relative positional relationship between the car and the neighboring car is dynamically predicted in real time, and then a two-degree-of-freedom dynamic collision time model and a two-degree-of-freedom collision time threshold model are proposed and designed. Finally, based on the output parameters of the above model, a two-degree-of-freedom curved road collision prevention warning system of automobile based on V2X technology is proposed, and a layered early warning mechanism is established. Through the PreScan environment, the typical working conditions and early warning strategy models are built by Matlab & Simulink, and the simulation of the early warning strategy is completed.
Li, Xuanhe, Wu, Jian, He, Rui, Zhu, Bing, Zhao, Jian, Zhou, Hang
Flow Field Experimental Study in Brake Discs with Aerodynamic Ventilation Columns06-13-01-00042/27/2020
This work presents a new design of ventilation pillars in ventilated brake discs. The use of National Advisory Committee for Aeronautics (NACA) aerodynamic profiles is proposed. Of the references consulted, there is no standard or procedure that indicates how the pillars should be installed in the ventilated discs. Therefore, it is proposed using the Kaplan’s error triangles theory of turbo hydraulic machinery to have a geometrically orderly way of placing the NACA 66-209 profiles from the suction diameter to the discharge diameter. To validate this new design, a 1:1 scale acrylic disc model was constructed, and tests were conducted in water using the particle tracking velocimetry technique to characterize the water model. The water experiment was performed at test speeds of 35, 41, 48, and 54 rpm. From the experiment in water, it is possible to visualize the flow field from the suction diameter to the model discharge diameter and scale the results to the prototype in air. Being 54 rpm in water equivalent to N = 1020 rpm in air, the radial velocity is 15.4% higher than a straight vanes disc. In addition, comparing the mass flow at the point of maximum speed, it is observed that the results obtained in this work are 40.21%, 65.49%, and 98.11% higher than those obtained by other works. Finally, the error of the accumulated experimental bias is extremely low, where the maximum error did not reach 1.17%. For this reason, it can be ensured that both the measurements made as well as the results obtained are highly reliable.
Rivera López, Jesús Eduardo, Gutiérrez Paredes, Guadalupe Juliana, Quintero Orozco, Abner, Tamayo Meza, Pedro Alejandro, Orozco Durán, Gabriela Esmeralda, Arciniega Martínez, José Luis
Regressions of brake pads compressibility from experimental data2019-36-00141/13/2020
One of the critical characteristics in a brake pad is its deformation when subjected to compressive loads. This deformation is called compressibility, which can be obtained quantitatively through compression cycles performed by a specific test bench. However, such testing is costly and long enough not to meet the demand of manufacturers of friction materials. To overcome this difficulty, this work presents regressions for the estimation of compressibility through the natural frequencies of the pads, since they can be obtained quickly and at low cost through a simple modal analysis. The theoretical basis for the correlation between compressibility and natural frequencies includes the theory of elasticity - which defines an inverse relationship between strain and stiffness - and the theory of vibrations, which defines the natural frequencies of a mechanical system as a function of its mass matrices and stiffness. Since the dependent variable (compressibility) and explanatory variable (natural frequency) are linked to stiffness, it is theoretically plausible to direct estimative. As additional explanatory variables, in addition to the experimental data of natural frequencies, the work uses the mass values and the temperature during the natural frequency measurement to improve the regression models.
Suetti, André Garcia Lima
Influence of Pads and Brake Disc wear on Brake Squeal Noise2019-36-00051/13/2020
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 between the frequency of the noises found experimentally and the frequency of the unstable modes found in the virtual model. A parametric analysis was performed simulating the wear of the disks and pads to understand the effect of the mass variations and stiffness on the instability of the system. According to the results found in the analyzes that simulate the wear, with the decrease, mainly the thickness of the brake pads, there was an increase of numbers of unstable modes, that is, the brake system is more prone to squeal generation.
dos Anjos, Marco Túlio Batista, Gutiérrez, Juan Carlos Horta, Ferreto, Cláudio Junior, Silva, Felipe Dornellas, Donadon, Lázaro Valentin
Brake noise analysis on tractive axle of 6x2 tractor vehicle2019-36-00081/13/2020
This study aims at analyzing the causes of noise in a heavy vehicle brake system (6x2 tractor) and proposing solutions to improve comfort during braking as it is known that, during the activation of the automotive brakes, noise can be generated in different frequency bands that can cause discomfort to the user and the study of how to reduce it is considerably important to bring more comfort in its use. As a working methodology, firstly, comparative analysis of dimension and material were performed between the axle assembly that presented noise and another axle assembly of a vehicle with no noise adopted as reference. This information was used as the basis for the frequency and acceleration virtual analysis that were validated with vehicle instrumentation and data acquisition. In parallel, vehicle tests with different brake friction materials were conducted. The answers of the dimension and material analysis from the axles assemblies highlighted the specificities of each of them but did not show great influence in the observed noise incidence. The vehicle instrumentation and data acquisition besides validate the virtual data, also showed the system amplitude of vibration which, through comparative tests with the same vehicle with the reference axle and similar vehicles, showed high variation in the acceleration and amplitude of vibration. The vehicle tests with different brake friction material varied the stiffness of the brake system, however, showing no evolution in its integrality but causing the noise at different braking pressure of the presented in those conditions. It is concluded that the difference between the axles assemblies is the assembly of the brake system “S” cam axle which, when actuated, has the rotation contrary to the wheel rotation, which can originate the variations in the acceleration and amplitude of vibration verified in the data acquisition and, therefore, may influence in the noise appearance.
Fortuna Pizzi, Rafael, Soares Júnior, Getúlio, Tonetti Anselmo, Pablo, Do Nascimento, Vagner, dos Santos, Roger Lusa, Severo Antunes, Diego, Masotti, Diego, Horta Gutierrez, Juan Carlos
Commercial vehicle pedal feeling comfort ranges definition2019-36-00161/13/2020
The brake pedal is the brake system component that the driver fundamentally has contact and through its action wait the response of the whole system. Each OEM defines during vehicle conceptualization the behavior of brake pedal that characterizes the pedal feel that in general reflects not only the characteristic from that vehicle but also from the entire brand. Technically, the term known as Pedal Feel means the relation between the force applied on the pedal, the pedal travel and the deceleration achieved by the vehicle. Such relation curves are also analyzed in conjunction with objective analysis sheets where the vehicle brake behavior is analyzed in test track considering different deceleration conditions, force and pedal travel. On technical literature, it is possible to find some data and studies considering the hydraulic brakes behavior. However, for pneumatic brake systems, the pedal feel theoretical study is not usual, where is normally used for these developments, exclusively the subjective evaluation which become necessary to have more specialists to define the brake pedal behavior. Throughout this article will be revised the characteristics concepts of brake pedal and what impact in pedal feel in pneumatic brake systems. Vehicular measurements will be also presented which provided important information on comfort curve definition of commercial vehicles pedal feel, correlating these measurements with subjective analysis and also considering technologies like ABS and EBS. Such study creates a methodology with objective parameters for the future vehicles to be developed by the brand.
Bolognesi Prado, Wesley, Faria Iombriller, Silvia, Rodrigues da Silva, Marco André, Renato Oliveira, Lázaro
Development challenges of hydraulic brakes for commercial vehicles2019-36-00131/13/2020
The automotive research and development environment is increasingly challenging and complex, full of new technologies, regulations and customized customer needs. In addition, the cargo transportation market is very dynamic and competitive, becoming complex the strategies for companies in this segment. According to Anfavea (2018), this trend, especially in large urban centers, has driven the intention to use light commercial vehicles to capillize deliveries in destinations with a high demographic concentration and traffic limited to medium and heavy vehicles. In this scenario, the demand for diversified products is increasing in order to overcome the main tradeoff: “minimizing the size of the trucks and maximize the load capacity”. It brings the number of complex projects. The brake system is greatly impacted in these developments mainly because light commercial vehicles are situated in a weight range that we can call "identity crisis" if on the one hand they need an upgrade compared to a conventional car and use the hydraulic brake on the other one need a downgrade of a medium or heavy truck that brings robustness and pneumatic brakes. The definition of the type of assistance is a determining factor, hydraulic brake; pneumatic brake or a hybrid brake (air over hydraulic). Each type has its advantages and disadvantages, which are directly related to the vehicle's application such as installation package, serviceability, service brake costs and performance and especially parking brake. This work shows the study and development of the brake system including the detailed presentation of a dry caliper, implemented as disruptive innovation technology. It also has a new concept applied to a commercial vehicle, developed in Brasil and used as footprint own knowledge for the specific needs of the market and provides a very cost-benefit commitment for the customer, yet brings the wished confidence of the parking brake function for drivers.
Vetter, Narã Vieira, Carlos de Oliveira, Antonio, Fontes, Eduardo Henrique Souza, Nogueira, Felipe, Fonseca, Guilherme Henrique, Nuss de Souza, Luis Fernando, Oliveira dos Reis, Rodrigo de, Manenti, Vangelo Cardoso
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 are doing the maximum work in decelerating the motorcycle. Therefore an optimal brake force distribution is one that locks both the wheels at the same instant. In practice, however, a rider would avoid a front wheel lock-up as it would make the motorcycle challenging to steer. In theory, an apt distribution of the braking forces between the front and rear wheels maximizes the overall braking efficiency of the motorcycle whilst reducing its stopping distance. This paper examines the plausible performance gains of load sensing brake force distribution in a motorcycle.
Chakraborty, Apurva
A New Appraisal of the Thermomechanical Behaviour of a Hybrid Composite Brake Disc in a Formula Vehicle2019-28-257211/21/2019
The present work promotes a hybrid composite brake disc for thermal and structural analysis of a formula vehicle. In order to reduce the un-sprung weight without compromising the strength, hybrid composite materials were incorporated in the disc plates of the braking system. In the disk brake system, the disc is a major part of a device used for slowing or stopping the rotation of a wheel. Repetitive braking of the vehicle leads to heat generation during each braking condition. Based on the practical understanding the brake disc was remodeled with unique slotting patterns and grooves, using the selected aluminium alloy of (AA8081) with reinforcement particle of 15wt% Silicon carbide (SiC) and 3wt% Graphite (Gr) as a hybrid composite material for this proposed work. By varying slotting pattern and groove angles the transient thermal and structural analysis using ANSYS workbench on the hybrid composite disc plate of disk brake is done. The main purpose of this study is to analyse the thermomechanical behavior of composite brake disc for a formula vehicle under severe braking conditions. To ensure the braking conditions, the coupled field analysis is done on the disk brake to determine the deformation and the Von Mises stress developed in the disc for both solid disk and disk provided with multiple ventilations (slotting patterns and grooves angles) using the hybrid composite material to improve the performance of the brake disc. Hence the best suitable design of disc plate with the hybrid composite material is recommended based on the performance, strength and rigidity criteria. Also, it will be recommended for fabrication and real-time usage in formula vehicles.
Ranganathan, Soundararajan, Kuppuraj, Sathishkumar, Gopal, Shanthosh, Chandrasakaran, Pradeep
Automotive Air Brake Line Couplers (Gladhands)J318_201911 (Historical)11/20/2019
This SAE Recommended Practice is intended to provide design, interchangeable dimensions, testing procedures, performance requirements, and minimum identification for gladhand-type air line couplers used to connect the brake systems of trucks, truck-tractors, trailers, and dollies when these vehicles are joined to operate as a combination unit.
Truck and Bus Brake Supply and Control Components Committee
Road Vehicles - Friction Materials - Finished Brake Pad Normalized Elastic Constant of Friction MaterialJ3175_201911 (Current)11/20/2019
This SAE standard specifies a method for testing and measuring a normalized elastic constant of brake pad assemblies using ultrasound. This document applies to disc brake pad assemblies and its coupons or segments used in road vehicles.
Brake Linings Standards Committee
Analysis of Metal Pick-Up Formation Process within Automotive Brake Pad05-13-01-000311/19/2019
Metal Pick-Up (MPU) is a problematic phenomenon in automotive disc brakes. MPU generally forms as some metal lumps on the surface of the brake pad. If brake pads have MPU, during braking they would cause grooving of the disc rotor, generating brake noise and deteriorating the performance of the brake. The previous literature has so far reported that the source of the MPU is an Fe component from a disc rotor or brake pads. However, only a few of the generation mechanisms of MPU have been proven. We investigate MPU to completely elucidate the mechanism of MPU generation by using different analyses than the previous literature. First, to find out the source of MPU generation, we focus on the chemical reaction of a certain component with wear debris during braking, and some of the verification experiments are conducted under the conditions of simulated friction interface. Second, to clarify the change in the form of the MPU growth process, the crystal structure of MPU is analyzed in detail by using the world’s largest synchrotron radiation facility (SPring-8). The results in this study reveal new facts about the source of MPU generation and the MPU growth process that have so far only been supposed.
Noda, Hirokazu, Takei, Takahiro
Autopilot Strategy Based on Improved DDPG Algorithm2019-01-507211/4/2019
Deep Deterministic Policy Gradient (DDPG) is one of the Deep Reinforcement Learning algorithms. Because of the well perform in continuous motion control, DDPG algorithm is applied in the field of self-driving. Regarding the problems of the instability of DDPG algorithm during training and low training efficiency and slow convergence rate. An improved DDPG algorithm based on segmented experience replay is presented. On the basis of the DDPG algorithm, the segmented experience replay select the training experience by the importance according to the training progress to improve the training efficiency and stability of the training model. The algorithm was tested in an open source 3D car racing simulator called TORCS. The simulation results demonstrate the training stability is significantly improved compared with the DDPG algorithm and the DQN algorithm, and the average return is about 46% higher than the DDPG algorithm and about 55% higher than the DQN algorithm.
Tian, Zhewen, Zuo, Xiaochao, Li, Xiaoning
Parking Brake Structural Integrity Test Procedure Vehicles Over 4500 kg (10 000 lb) GVWR—Truck and BusJ1476_201910 (Current)10/21/2019
This SAE Recommended Practice establishes a method of evaluating the structural integrity of the parking brake system of all new trucks, buses, and combination vehicles designed for roadway use in the following classifications: TRACTOR, TRAILER, TRUCK, AND BUS: over 4500 kg (10 000 lb) GVWR.
Truck and Bus Foundation Brake Committee
Outboard Mounted Brake Drum/Disc Wheel Hub Interface Dimensions - Truck and BusJ1671_201910 (Historical)10/17/2019
This recommended practice contains dimensions and tolerances for outboard mounted brake drums and disc wheel hubs in the interface areas. This recommended practice is intended for outboard mounted brake drums and disc wheel hubs commonly used on class 7 and 8 commercial vehicles. Included are SAE J694 mounting systems II, III, IV, XIV, and X. Special and less common applications are not covered.
Truck and Bus Wheel Committee
Nondestructive Measurement of Residual Strain in Connecting Rods Using Neutrons05-12-03-001810/15/2019
Abstract Increasing the strength of materials is effective in reducing weight and boosting structural part performance, but there are cases where the residual strain generated during the process of manufacturing of high-strength materials results in a decline of durability. It is therefore important to understand how the residual strain in a manufactured component changes due to processing conditions. In the case of a connecting rod, because the strain load on the connecting rod rib sections is high, it is necessary to clearly understand the distribution of strain in the ribs. However, because residual strain is generally measured by using X-ray diffractometers or strain gauges, measurements are limited to the surface layer of the parts. Neutron beams, however, have a higher penetration depth than X-rays, allowing for strain measurement in the bulk material. The research discussed within this article consists of nondestructive residual strain measurements in the interior of connecting rods using the Second Generation Neutron Residual Stress Mapping Facility (NRSF2) at Oak Ridge National Laboratory (ORNL), measuring the Fe (211) diffraction peak position of the ferrite phase. The interior strain distribution of the connecting rod, which was prepared under different manufacturing processes, was revealed. By the visualization of interior strains, clear understandings of differences in various processing conditions were obtained. In addition, it is known that the peak width, which is also obtained during measurement, is suggestive of the size of crystallites in the structure; however, the peak width can additionally be caused by microstresses and material dislocations.
Ikeda, Tomohiro, Jeffery, Bunn R., Fancher, Christopher M., Motani, Ryuta, Matsuda, Hideki, Okayama, Tatsuya
Fatigue Life Prediction of Heavy Duty Automobile’s Brake Drum through Coupled Thermo-Mechanical Analysis2019-28-003110/11/2019
The aim of this paper is to demonstrate the methodology to simulate the induced stresses/strains due to thermo-mechanical loading of automobile brake drum.. The brake drum undergoes mechanical load due to applied brake pressure and thermal load due to friction generated between brake pad and brake drum while brake is applied. This coupled thermo-mechanical loading affects the life of the brake drum as the stiffness of the brake drum is reduced. The conventional method of simulating this problem is done using Lagrangian discretization in which the load is applied and inertia effect due to angular velocity is applied to a drum at static condition. In contrast, in this paper Eulerian discretization is adopted for finite element analysis, in which drum brake model is discretized as spatially dependent that facilitates actual rotation of brake drum with simultaneous application of brake load resulting more precise simulation. A sequentially coupled transient thermo-mechanical analysis is carried out using ABAQUS 6.12 simulation tool to predict the induced stresses/strains and fatigue life of the brake drum.
Annamalai, Krishnamoorthy, Naiju, Chooriyaparambil Damodaran
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 Solidworks 2017 and is analyzed for the factor of safety, stress, and deformation is ANSYS workbench 16.2.
Ugemuge, Mosam, Das, Sreethul
Setting Preload in Heavy-Duty Wheel BearingsJ2535_201910 (Current)10/7/2019
This SAE Recommended Practice applies to the four primary, large volume applications in the class 7-8 heavy-duty market place, as specified in SAE J1842: a “N” trailer axle b “R” powered rear axle c “FF / FG” nonpowered front axle d “P” trailer axle This document applies to on-highway applications. It is not applicable to those applications that exceed the GAWR ratings or the load line restrictions listed in columns “A,” “B,” and “C” of Table 1. Load lines are measured from the inboard bearing cup backface as shown in 3.4. This document establishes preload force values only. The methodology to obtain these force values must be determined by the fastener supplier and/or axle assembler. This document reviews the bearing system. It is NOT intended to prescribe (new or existing) axle and/or hub manufacturers’ ratings and/or specifications.
Truck and Bus Wheel Committee
The Improvement Brake’s Qualities of Vehicle by Developing the Method of the Choosing Frictional Pairs of the Brakes Mechanisms2019-01-21459/15/2019
One of the reasons for the large number of road accidents on highways in Ukraine [1] is the instability of the braking properties due to the unstable characteristics of the brake mechanisms’ friction pairs. The manufacturer produces new automobiles with installed brake pairs (brake pads and their counter bodies), which have passed long-term tests for the stability of the friction coefficient and braking forces distribution of between the axles. This ensures the compatibility of the friction pairs characteristics for front and rear brake mechanisms according to the criteria of heat resistance. During operation, instead of worn-out brake pads, brake discs and drums, drivers can purchase new ones, manufactured as spare parts. However, in the well-known literature there are no methods that allow to check the compatibility of the friction pairs characteristics for front and rear brake mechanisms according to the criteria of heat resistance. In the article a method for choosing a set of friction pairs of brake mechanisms for passenger car during operation is proposed. Assessment of the compatibility of the friction pairs characteristics for front and rear brake mechanisms was carried out according to the criteria of heat resistance.
Podrigalo, Mikhail, Klets, Dmytro, Kholodov, Mykhailo, Bogomolov, Viktor, Turenko, Anatoliy, Molodan, Andrii, Rudzinskyi, Volodymyr, Tarasov, Yurii, Mykolai, Aloksa, Hatsko, Vasyl
Objective Method for Crack Detection in Brake Friction Material2019-01-21139/15/2019
Friction material manufacturing is a complex process where numerous raw materials are mixed, pressed, and cured to make brake pads. It is important to have a consistent manufacturing process that can produce a brake pad that satisfies the vehicle braking requirements. A basic and critical requirement for any brake pad is structural integrity with no internal cracks. In this work a series of processing changes were made to intentionally produce internal cracks in the friction material. Various pad crack detection methods were studied, and their advantages and disadvantages are discussed in detail. One of the crack detection methods used an ultrasonic measuring instrument which gives objective data in the form of calculated modulus of elasticity and signal loss. The details of the machine and how the measurements are obtained are discussed. The modulus calculation is also described. Additionally, random pads with and without cracks were selected and checked using subjective and objective crack detection methods. The comparison analysis is discussed, and authors were able to show the difference between cracked and non-cracked pads using several methods. Conclusions and recommendations are made based on the data from these studies.
Divakaruni, Saikiran, Yuhas, Donald, Vorres, Carol, Kaatz, Richard
Brake Pedal Feeling Comfort Analysis for Trucks with Pneumatic Brake System2019-01-21409/15/2019
The brake pedal is the brake system component that the driver fundamentally has contact and through its action wait the response of the whole system. Each OEM defines during vehicle conceptualization the behavior of brake pedal that characterizes the pedal feel that in general reflects not only the characteristic from that vehicle but also from the entire brand. Technically, the term known as Pedal Feel means the relation between the force applied on the pedal, the pedal travel and the deceleration achieved by the vehicle. Such relation curves are also analyzed in conjunction with objective analysis sheets where the vehicle brake behavior is analyzed in test track considering different deceleration conditions, force and pedal travel. On technical literature, it is possible to find some data and studies considering the hydraulic brakes behavior. However, for pneumatic brake systems, the pedal feel theoretical study is not usual, where is normally used for these developments, exclusively the subjective evaluation which become necessary to have more specialists to define the brake pedal behavior. Throughout this article will be revised the characteristics concepts of brake pedal and what impact in pedal feel in pneumatic brake systems. Vehicular measurements will be also presented which provided important information on comfort curve definition of commercial vehicles pedal feel, correlating these measurements with subjective analysis and also considering technologies like ABS and EBS. Such study creates a methodology with objective parameters for the future vehicles to be developed by the brand.
Bolognesi Prado, Wesley, Iombriller, Silvia Faria, Silva, Marco Andre, Oliveira, Lázaro Renato
Squeal Noise Improvement by High Damping & High Stiffness under Layer Material2019-01-21119/15/2019
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 verification, the study focuses on the PAD damping ratio and squeal noise performance in the 1st bending vibration of the PAD. It is clarified that the PAD damping ratio increased as the loss modulus increases, which leads to improve squeal noise. In conclusion, this research proves that the high damping and high stiffness UL material is effective for squeal noise improvement.
Nishioka, Masato, Johnson, Leanne, Rosalez, Sean, Suzuki, Shusuke
Frequency Inspection of Brake System Components2019-01-21179/15/2019
Frequency inspection has long been a tool utilized by manufacturers of brake system components as a means of quality control. This is important to combat perceived defectiveness of a system that experiences issues, such as brake squeal, as well as to identify actual defects in the parts going out to customers. Every component has its own resonance frequencies based on the dynamics of that component. Knowledge of the resonance frequencies of each component provides insight that can prevent manufacturers from sending out defective units, whether they be perceived defects or actual defects. NVH engineers who understand these phenomena perform theoretical analysis and acquire experimental data in the lab to gain insight into their parts that will eventually be produced on the assembly line. Unfortunately, the frequency requirements, and the consequences thereof, defined by the NVH engineers can still remain somewhat of a mystery to the manufacturing engineers who are tasked with applying them. Oversights in specifications can lead to avoidable scares that lead to delays and downtime. For example, differences in accelerometer placement on a brake rotor from the lab to the assembly line can lead to issues such as variable frequency reporting. This leads to inaccurate data reporting, which leads to poor Gage R&R. A basic understanding of vibration and how to analyze data would allow the manufacturing engineer to troubleshoot such an issue and prevent unnecessary delays. This paper will attempt to take these concepts beyond the specification sheet and into the science and mathematics behind the dynamics of the different components of the total brake system. The knowledge gleaned from this analysis allows for intelligent decision making for go/no-go on the production line, as well as root cause analysis in the lab.
Cagle, Robert
Brake Rotor Corrosion and Friction Cleaning Effect on Vehicle Judder Performance2019-01-21159/15/2019
Brake disc corrosion has emerged as an important field of study within the automotive industry due to the wide range of lining materials that are currently used worldwide, and their inherent rust-cleaning properties. The presence of oxide layers irregularly deposited on the cast iron disc surfaces usually leads to a forced, braking-induced vibration that can reach the driver’s position as a pronounced annoyance. Hence, the friction material composition directly impacts on the judder performance during the early corrosion-removal stage. This study incorporates both dynamometer and vehicle tests into the definition of a predictive methodology that allows corrosion-induced vibrations to be investigated at both system and vehicle levels. The oxide film is artificially generated by means of a salt spray chamber under steady-state climate conditions in order to guarantee a repetitive and robust procedure. The vibration response of the system is objectively evaluated in the form of caliper accelerations and pressure (BPV) / torque (BTV) oscillations throughout a reduced rust-removal test sequence composed of 30 snubs; basic spectral and order analyses are conducted with the gathered data. Furthermore, vehicle-based results are correlated with the subjective ratings that an expert driver gives to the different vibrations perceived at chassis level. The in-service roughness of the oxide layer, on the other hand, is indirectly monitored by using a couple of non-contacting capacitive sensors that measure the variation in disc thickness (DTV). Ultimately, this paper is intended to characterize the inherent corrosion-cleaning capability of different friction materials -paying special attention to the presence of copper-, as well as revealing their impact on the vehicle judder subsequently induced during the actual removal of the oxide layers.
Molina Montasell, Narcís, Ferrer, Bernat
Divergence of Thickness Loss vs. Weight Loss, Friction and Wear Behavior of Heavy Truck Brake Blocks: Development of a New Test Procedure for the Chase Tester2019-01-21079/15/2019
Heavy truck brake blocks are found to swell (or expand) permanently during testing or usage, especially so at high temperatures, thus leading to longer durability as measured by thickness loss, similar to light vehicle disc pads. This swelling phenomenon occurs continuously in the layer adjacent to the friction surface during testing or usage; not a one time event. The thickness loss estimated from the weight loss is always greater than measured thickness loss. Brake block wear does not increase linearly with increasing normal load, and the load-sensitivity of block wear is very much dependent on the products. A new test procedure has been developed for generating friction-vs.-temperature and wear-vs.-temperature data at a constant temperature employing intermittent braking on the Chase Brake Lining Quality Tester (SAE J661) and friction material wear can be compared on equivalent-work basis.
Rathee, Aman, Sharma, Devendra Kumar, Singh, Shivraj, Rhee, Seong Kwan
The Normal-Load and Sliding-Speed Dependence of the Coefficient of Friction, and Wear Particle Generation Contributing to Friction: High-Copper and Copper-Free Formulations2019-01-21319/15/2019
Automotive brakes operate under varying conditions of speed and deceleration. In other words, the friction material is subjected to a wide range of normal loads and sliding speeds. One widely accepted test procedure to evaluate, compare and screen friction materials is the SAE J2522 Brake Effectiveness test, which requires full-size production brakes to be tested on an inertia brake dynamometer. For the current investigation, disc pads of two types of 10 different formulations (5 high-copper and 5 copper-free formulations) were prepared for testing on a front disc brake suitable for a pickup truck of GVW 3,200 kg. Each pad had 2 vertical slots, and one chamfer on the leading edge and also on the trailing edge of the pad. One segment of the test procedure looks at the coefficient of friction (Mu) under different brake line pressures and different sliding speeds to determine its stability or variability. In all cases, the Mu is found to be dependent on the normal load and sliding speed, contrary to the commonly called “Amontons-Coulomb’s Laws of Friction”. According to Wikipedia, Guillaume Amontons (1663 - 1705) observed that the force of friction was directly proportional to the applied load, meaning constant coefficient of friction and that the force of friction was independent of the apparent area of contact, while Charles-Augustin de Coulomb (1736 - 1806) observed that when a piece of metal was slid against wood, the coefficient of friction became very dependent on the normal load and the sliding speed and warned about the limitations of Amontons’ findings. Now one wonders how and when the expression of the so-called “Amontons-Coulomb’s Laws of Friction” surfaced as universal laws. According to analysis of the test data generated in this investigation, the average Mu is found to increase linearly with the increasing total wear rates of the disc and the 2 pads (the inboard and the outboard pads) in the case of copper-containing formulations and also in the case of copper-free formulations: each type of formulation has its own linear relationship. The average Mu is found to consist of 2 parts. One part is dependent on the total wear rates of the disc and the 2 pads while the other part, which is the Mu at zero wear, is independent of the wear rates. Also in this investigation, the disc wear rate is found to be directly proportional to the total wear rate of the 2 pads (the inboard and the outboard). As the pad wear is reported to be best described by a power function of the normal load and the sliding speed, a power function becomes applicable to the disc wear rate as the disc wear rate is proportional to the pad wear rate. So the wear dependent part of the Mu becomes a power function of the normal load and the sliding speed.
Rhee, Seong K., Sriwiboon, Meechai, Tiempan, Nipon, Kaewlob, Kritsana
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