Browse Topic: Brake shoes

Items (144)

INTEGRATED ACTIVE SAFETY SYSTEM FOR MOTOR GRADERS

2021-26-013709/22/2021

Safety of the operators in any equipment can be achieved by both passive and active systems. Passive safety system includes Seat belt, primary air bag, bumper, and other structural components which protects the operator from injuries during accidents. On the other side, Active safety systems like Braking, Steering, Collision avoidance system, operator fatigue monitoring systems minimise and eliminates the accidents among which the Brake system is primarily used to control and stop the equipment. Motor graders are work equipment which are designed to carry out many works like grading, spreading, levelling, metal mixing in road construction and many other infrastructure projects. Considering the field operating conditions of motor grader, it is very essential to provide excellent brake system to control and stop the equipment. In order to obtain maximum productivity the equipment speed is kept substantially high. Brake systems are operated using Air, Hydraulics, etc., among which the Air

KUMARAN, RAJASEKAR, hs, satish chandra

Design of Active Water-Cooled Drum Brake System for Heavy-Duty Truck

2020-01-163910/05/2020

On account of the traditional friction brake for heavy-duty truck (HDT), the massive quantity of heat accumulating constantly because of frequent using of friction brake system in the long and steep downhill road leads to brake temperature rising rapidly. Affected by structure frictional couple installed in the closed environment of the brake drum, it is difficult to dissipate the heat in time via heat conduction, heat radiation and heat convection, and the heat fade phenomenon of the brake emerges easily. The HDT would be in danger because of braking efficiency descending. This paper proposes an active water-cooled drum brake system (AWBS) to solve the problem. According to the principle of engineering thermodynamics, the structure and size of the back-stretching water jacket of brake shoe and the inner riveted the friction plate of brake drum are designed with restrained of GB 12676-2014 ‘Technical requirements and testing methods for commercial vehicle and trailer braking systems

Shi, Peilong, Yu, Qiang, Chang, Hong, Zhao, Xuan, Xu, Shuo

Air Brake Performance and Wear Test Code Commercial Vehicle Inertia Dynamometer

J2115_202008 (Current)

08/20/2020

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

Air Brake Performance and Wear Test Code Commercial Vehicle Inertia Dynamometer

J2115_202008-TEST-REC (Historical)08/20/2020

Truck and Bus Foundation Brake Committee

Low-Duty Inertia Dynamometer Hydraulic Brake Wear Test Procedures for Vehicles Above 4536 kg (10000 pounds) of GVWR

J3006_202005 (Current)

05/26/2020

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

Truck and Bus Hydraulic Brake Committee

High-Preload Deflection and Compressibility Test Procedures for Friction Materials

J2468_201811 (Current)11/12/2018

This standard specifies a method for testing and measuring the deflection of friction materials assemblies and compressibility of friction materials. This standard applies to disc brake pad assemblies and its coupons or segments, brake shoe lining and its coupons or segments, and brake blocks segments used in road vehicles. This SAE test method is consistent in intent with the ISO 6310 and the JIS 4413.

Brake Linings Standards Committee

Test Procedures for Shear Strength of Automotive Brake Pads and Brake Lining Assemblies

J840_201711 (Current)11/15/2017

Brake Linings Standards Committee

Combined Hill Descent Braking Strategy for Heavy Truck in the Featured-Slope

2017-01-253509/17/2017

The continuous braking for the brake drum will cause the brake thermal decay when the heavy truck is driving down the long slope in the mountain areas. It reduces the heavy truck’s braking performance and the braking safety. The engine braking and the hydraulic retarder braking both consume the kinetic energy of the heavy truck and can assist the truck driving in the mountain areas. This research proposes a combined hill descent braking strategy for heavy truck based on the recorded information of the slopes to ensure the braking safety of the heavy truck. The vehicle dynamic model and the brake drum temperature rising model are established to analyze the drum’s temperature variation during the downhill progress of the heavy truck. Then based on the slope information, the combined braking temperature variation is analyzed considering the characteristics of the engine braking, the drum braking and the hydraulic retarder braking. The research result shows that the brake drum’s

Xu, Yongbing, Mei, Binyu, Xiao, Longjie, XIA, Wanyang, Tan, Gangfeng

Studies on Axial and Tangential Properties of Brake Pads

2017-36-001005/24/2017

The knowledge of the elastic properties of friction materials is especially important in the development of brake systems. The stiffness of the system directly impacts on the consumption of the fluid during braking and the user interaction with the brake pedal, in addition to being strongly linked to the occurrence or not of certain types of noise. For the analysis of brake pad stiffness, is well known the compressibility equipment, which evaluates the deformation subject to a load in the axial direction. The first stage of the work proves that the compressive deformation of the pad has a non-linear behaviour as a function of the applied force. Based on this non-linearity, tests are carried out on 93 brake pads, where trends between the instantaneous deformation and the final compressibility result are sought. In the second step, we try to evaluate the stiffness of the friction material in the tangential direction, where a new method is proposed using the shear equipment, also well

Suetti, André G. L., Correia, Carlos Eduardo

Experimental Study of Howl Noise Phenomenon Related to Drum Brake Squeal

2017-36-000705/24/2017

The improvement of motor’s power requires consequently the improvement in brake system also. The kinetic energy of moving vehicles is transformed in a big part of heat, but there is a part that can be transformed in vibration and sound pressure. One of these vibration and sound pressure complain is known as howl noise. The howl noise complain is very intense and uncomfortable for passengers and pedestrians. Today, the customers spend a lot of money in his vehicles comfort and this disorder can’t occur. This paper presents a methodology which uses Experimental Modal Analysis (EMA) and Operational Modal Analysis (OMA) to survey the dynamic behavior of suspension and brake systems at the howl noise occurrence condition.

Guimarães, Luiz Roberto, Abreu, Robson Demétrius Araújo, Carvalho, Ademir, Ferreto, Claudio Jr.

Methodology of Automatic Slack Brake Adjuster Definition Considering Foundation Brake System Characteristics

2017-36-000405/24/2017

S-cam brakes concept are largely used by commercial vehicles around the world due to its low cost, easy maintenance and robustness. An important component of s-cam brakes is the slack adjuster, that is responsible for amplify brake chamber forces and assure correct lining and drum clearance. Therefore usually slack adjuster mechanism characteristics are defined only by empiric method considering trial and error tentative. This paper aims to demonstrate a methodology created to develop new air s-cam brakes slack adjuster definition taken in consideration its interface with other brake components. During this study was identified design specification for each component and its influence on adjustment process. It was verified the intrinsic characteristics of slack adjuster mechanism and developed a calculation tool to predict its actuation on the brake. The interface of slack adjuster with other foundation brake components and drum compliance were also studied. In order to validate the

Prado, Wesley Bolognesi, Iombriller, Silvia Faria, Chiu, Jonathan Orsi, Roman, Alexandre

Experimental Study of Bus Noise Phenomenon in a Suspension System Assembled with Drum Brakes Through Modal Analysis Techniques

2016-36-018910/25/2016

The automotive industry currently has a big concern with the vibro-acoustic comfort. The growth of concurrence and the clients requirement becomes necessary the researches in new techniques for analysis and improvement. Hence many vibro-acoustic phenomena causes uncomfortable noises in a vehicle. One of this noises is descendant of braking system and is known as Bus Noise. This paper presents a methodology which uses Experimental Modal Analysis (EMA) and Operational Modal Analysis (OMA) to survey the dynamic behavior of suspension and brake systems at the Bus Noise occurrence condition.

Guimarães, Luiz Roberto, Abreu, Robson Demétrius Araújo, Ferreto, Claudio Junior

Alkali-Activated Inorganic Based Brake Pads: Realization and Performances of Alternative Friction Materials for a Concrete Industrial Application

2016-01-191309/18/2016

Organic brake pads for automotive can be defined as brake linings with bonding matrix constituted of high-temperature thermosetting resins. Bonded together inside the polymeric binder are a mix of components (e.g. abrasives, lubricants, reinforcements, fillers, modifiers…), each playing a distinctive role in determining the tribology and friction activity of the final friction material. The herein reported work presents inorganic “alkali-activated”-based materials suitable for the production of alternative brake linings (i.e. brake pads), by means of an unconventional low-temperature wet process. Exploiting the hydraulic activity of specific components when exposed to an alkaline environment, such peculiar inorganic materials are capable of coming to a complete hardening without the need of traditional high-temperature energivorous procedures. The main advantages of these materials resides in: the decreased embodied energy of the employed raw materials, the reduction of process costs

Sanguineti, Alessandro, Tosi, Federico, Bonfanti, Andrea, Rampinelli, Flavio

Test Component Specifications

J1802/1_201607 (Current)07/27/2016

Truck and Bus Foundation Brake Committee

Effects of ‘Black Steel’ and its Contribution to Premature Brake Pad Replacement and Brake Pad Failure

2015-01-266609/27/2015

The Global Brake Safety Council sees an increase in disc brake pads that are prematurely replaced before the end of the friction lining life cycle, due to: 1 Rust related issues such as separation of friction lining from the disc brake shoe 2 Fluctuation in critical dimensions. A leading cause for both issues is the use of mill scale steel, or ‘black steel’ (non-pickled and oiled). In the North American aftermarket, as there are little or no steel specifications for disc brake shoes, black steel is increasingly used. GBSC conducted research of discarded disc brake pads from job-shops and engaged in discussions with metallurgists, major pad manufacturers and OE brake foundation engineers to identify root causes of premature pad replacement and the effects of black steel used for disc brake shoe manufacturing. Mill scale is embedded in and around the bond line of the friction lining and the disc brake shoe, causing a weaker bond, susceptible to rust jacking. These oxides are also painted

Lambert, Scott

Innovative Concept of Front Disc Brake Module with Weight Reduction and Cost Optimisation

2014-01-250509/28/2014

The customer satisfaction index is higher for disc brake systems because of the advantages like less reaction time, shorter stopping distance and improved pedal feel compared to drum brake system. In current competitive market scenario and as per customer requirements, front disc brake module is becoming necessary. The brake system design is challenging task due to stringent performance meeting criteria and packaging constraints with weight optimization. Brake disc is very important component in the brake system which is expected to withstand high braking torque and dissipate heat during braking event. In existing car to replace front drum brake with disc brake module, vehicle needs to undergo legislative verifications and certifications with respect to pedal effort, stopping distance and circuit failed conditions etc. This paper explains development of disc brake system with novel brake disc during transition to switch from drum to disc brake with respect to packaging constraints

Shah, Ashesh, Patil, Sanjay, Abhyankar, Umesh

Hydraulic Wheel Cylinders for Automotive Drum Brakes

J101_201307 (Current)07/09/2013

This document specifies minimum performance and durability requirements for satisfactory vehicle usage, and it is applicable to wheel cylinder assemblies from commercial production, after production shipment, shelf storage, and remanufacture (factory rebuild).

Hydraulic Brake Components Standards Committee

Determination of Brake Fluid Temperature

J291_201304 (Current)04/09/2013

This code provides a test procedure for obtaining and determining extremely high brake fluid temperature encountered in the brake system of a vehicle that is equipped with disc brakes. Vehicles in normal operation may or may not produce brake fluid temperatures that are obtained in this procedure.

Road Test Procedures Standards Committee

Avoiding False Positive Asbestos Analysis in Polymer Matrix Composite Brake Linings

2013-01-049304/08/2013

Asbestos has been banned in many countries as industrial material, however the utilization of those fibers in brake linings results in friction properties that are so convenient, that linings containing them are still commercially available. To replace asbestos a large number of mineral phases is utilized in the formulation of polymer based friction material, and it is sometimes difficult to establish if they are present or not in finished brake pads and linings. Several clay minerals have been mistaken for asbestos because they present X-ray diffraction peaks that overlap with the diagnostic asbestos peak. A method to distinguish between the presence of regulated fiber minerals and allowed clay minerals in brake linings is presented using X-ray diffraction in association with a thermal treatment.

Hinrichs, Ruth, Vasconcellos, Marcos A.Z.

Swell, Growth, and Dimensional Stability of Friction Materials and Noise Insulators when Exposed to Elevated Temperatures

J160_201302 (Current)02/13/2013

This performance standard specifies a universal method of measuring the dimensional change of friction materials to determine the effects of temperature. The test applies to both, disc and drum type linings commonly used in hydraulic and air brake systems for automotive or commercial vehicle applications. This standard describes two main test procedures. Method A, where the friction material is in contact with a heated surface to simulate the heat input to the pad that occurs during actual usage. Method B uses an oven to heat the freestanding material and is an approximate procedure requiring less instrumentation. Method A is recommended for disc brake pad assemblies, noise insulators, or flat coupons; while Method B is recommended for curved drum brake linings.

Brake Linings Standards Committee

Impact of Pad Wear on the Pressure Dynamics of a Vehicle Braking System

2012-01-189709/24/2012

A vehicle braking system is used to provide acceptable drivability of the vehicle and ensure safety in different emergency situations that the vehicle may encounter. The braking system is used also as an integrated sub-system in many other important vehicle driving systems such as traction control, adaptive cruise control, accident avoidance and other vehicle systems in which the braking system plays an important role. This paper is dedicated to provide an accurate and at the same time simple enough hydro-mechanical braking system mathematical model that takes brake pad wear impact on the system pressure dynamics into consideration. A wear simulation procedure based on the concept of Archard's wear law is used and integrated in the nonlinear braking system model with flow compressibility taken into consideration. The presented model simulation results and the experimental tests results show good agreement and validate the confidence in the proposed model. Also, a reduced order model of

Haggag, Salem A., Abidou, Diaa

Hot Powder Preform Forging Technique for Making Brake Pad

2011-28-007610/06/2011

The present study deals with development of iron based MMC employed for brake pads by ‘Hot Powder Preform Forging’ technique. The conventional technique i.e. Compacting and sintering for manufacturing metalloceramic brake pads was successfully and economically replaced by using above process. Higher density levels can be achieved by hot powder pre-form forging technique hitherto not possible by sintering route. The mechanical properties of these materials were characterized using ASTM standards. Compacting and sintering technology suffers from certain major limitations such as inadequate joining of friction element with backing plate, poor density levels achieved in friction element owing to limited application of pressure during compacting, poor thermal conductivity due to high levels of porosity in the product, poor strength due to segregation of the impurities along prior particle boundaries (PPB's), anisotropy in the strength of the product owing to preferred direction due of

Ghazi, A. A. S., Chandra, K., Misra, P. S.

The Effect of Metal Pickup to the Friction Interfaces

2011-01-234809/18/2011

Metal pickup is a phenomenon that can be observed during dynamic braking with automotive disc brakes. Hard metallic particle agglomerations embedded in the friction materials rubbing surface can lead to severe disc scoring, accelerated wear and deterioration of the friction surface of either brake disc or brake pad. Such kind of surface conditions are also suspected for generating brake squeal, even if a direct root cause effect had not been proven so far. Disc scoring effects have been reported for all kinds of applications, reaching from small passenger cars up to commercial vehicles as well as railroad brakes. Although such phenomena are known since long, they still appear causing problems in brake systems of today. Some recent papers have described the effect and mentioned preferable conditions for the appearance of metal pickup. Specific procedures have been proposed for provocation of the effect to allow a better and more systematic investigation of the influencing parameters

Lange, Jürgen, Ostermeyer, Georg

Experimental and Analytical Investigation of Countermeasure against Squeal in Floating Type of Car Disc Brake

2011-01-157905/17/2011

This paper deals with low-frequency squeal phenomena generated in floating type of car disc brake units. First, the vibration characteristics of low-frequency squeal (about 2 kHz) were investigated. Here, in order to reproduce the squeal, a bench-test apparatus consisting of an actual automotive disc brake unit was utilized, itself comprising a disc, pad, and caliper. With this, the associated frequency characteristics were experimentally determined. It was found that the squeal is caused by coupled out-of-plane vibration modes among the disc and caliper due to Coulomb friction. As an experimental countermeasure, a dynamic absorber was applied to the leading side or the trailing side of the inner caliper. It was found that squeal can be suppressed when the natural frequency of the dynamic absorber is tuned so as to be near the frequency of the squeal, and that squeal can be suppressed even without viscous damping of the dynamic absorber. Also, using linear characteristic value analysis

Nakae, Takashi, Ryu, Takahiro, Sueoka, Atsuo

Test Component Specifications

J1802/1_201105 (Historical)05/16/2011

Truck and Bus Foundation Brake Committee

Performance of Non Asbestos Disc Brake Friction Material for Automotive Application - An Experimental Case Study

2010-01-167810/10/2010

Friction stability and wear resistance are key factors in brake system design and performance. The paper deals with the experimental investigation of friction characteristics and wear of three commercially available NAO (non-asbestos organic) disc brake friction materials viz. Grade A, Grade B and Grade C for a sport utility vehicle. The composites were evaluated for various friction performance properties such as average coefficient of friction, performance at various speeds (8.34 m/s to 38.89 m/s) and pressures (2 MPa to 12 MPa), fade & recovery behavior. These friction and wear characteristics were determined using four wheeler inertia dynamometer. The physical properties such as density, hardness, heat swell, water swell, adhesive bond strength at room temperature and adhesive bond strength at 400°C were studied according to Indian Standards. In addition SEM-EDX (Scanning electron microscope with energy dispersive X-ray) analysis was carried out for finding ingredients and micro

Kosbe, Pradnya Eknath, Sahasrabudhe, Niteen, Khandagale, Rahul, Kulkarni, Rajendra

Modification of Strain Distribution on Contact Surface of Shoe to Reduce Low Frequency Squeals for Brake Disc with Small Holes

2010-01-171510/10/2010

The purpose of this study is to propose an effective model to estimate the excitation force accompanied with stick-slip between shoe and disc, considering the strain distribution on contact surface of the shoe, and then to propose an effective concept to design the brake which reduced the brake squeal under practical use. In order to investigate the influence of configuration of the hole, three types of discs were prepared in which the size of holes was different. The SPL (Sound Pressure Level) and the frequency of squeal for three types of discs were measured when the brake squeal was observed at conditions of low sliding speed. The change of stability of the brake shoe passing on hole was analyzed by 2-D simplified brake system model. In order to investigate how the strain distribution of the shoe affected on the excitation force caused by stick-slip, FE (Finite-element) and FDTD (Finite-difference time-domain) analysis were utilized to simulate the elastic wave propagation in the

Obunai, Kiyotaka, Hagiwara, Sho, Okubo, Kazuya, Fujii, Toru, Nakatsuji, Tsuyoshi

Complex Mode Analysis on Disc Brake Squeal and Design Improvement

2009-01-210105/19/2009

Squeal noise in vehicle disc brakes is perceived by comsumers as both annoying and warranty cost. The mechanism is considered a mode coupling phenomenon also referred to as coalescence. In this paper, the system eigenvalues have been computed using a technique based on the • nite element method in order to obtain the dynamical properties of the disc brake assembly. The simulated squeal results were compared with the brake noise test that was in accordance with SAE J2521 standard and showed good correlation for some squeal frequencies which indicated that the research on disc brake squeal using complex mode could predict squeal propensity of the disc brake. Among the methods that have been used to control squeal noise, increasing the system damping has been shown to be very effective. The most commonly used method to increase system damping consists of attaching multi-layer laminates on the back of the brake pads. The comparison squeal test between disc brake with damping shim and one

Jun, Hou, Xue-xun, Guo, Gang-feng, Tan

An Investigation of Container Chassis Brake Lining Maximum Wear Rates

2009-01-009104/20/2009

An experimental investigation of the minimum mileage between required brake adjustments is presented, for a particular vehicle configuration, fully loaded, on a defined route. To insure the results represented maximum brake lining wear, or minimum adjustment interval, for a container chassis, the operator followed a strict protocol requiring the use of chassis brakes only, except when safety dictated otherwise. The data collected during the investigation have been tested against a proposed procedure for predicting brake adjustment frequency. This procedure should allow brake adjustment intervals to be predicted for other vehicle configurations and other service conditions.

Blythe, William

A Low-Cost Material Design of Gray Iron for Heavy-Duty Brake Drums

2009-01-021604/20/2009

For heavy-duty brake drums and rotors, grade G3500 is commonly used per SAE J431. Numerous studies have shown that grade G3500 alloyed with molybdenum (Mo) and nickel (Ni) is necessary in many heavy-duty applications. Because of the recent rapid rise in raw material costs of Mo and Ni, and the manufacturers’ inability to pass the costs onto the customers, there is a real need to develop new chemistries that will provide a relief to the cost pressure while maintaining the performance of the parts. In this paper, a low cost chemistry is proposed based on a material design concept that is centered on the microstructure design, which in turn is based upon the performance requirements of the parts. The chemical composition and casting processes are subsequently constructed to achieve a set of pre-described microstructure characteristics. Dynometer tests of simulated road conditions and limited road tests have shown that the brake drums made with new low-cost chemistry exhibited equal or

Huang, Yanjun

Effect of Thermo-Mechanical Behavior on Drum Brake Labyrinth Design

2008-32-006609/09/2008

In low speed bikes drum brakes are used on large scale. In drum brake system, brake shoes are relatively more enclosed by neighboring parts compared to disc brakes. Hence, drum brake cooling is not efficient like disc brake. This results in higher steady state temperature, which may lead to brake noise, brake fading, glazing etc. in drum brakes. Further, the high temperature plays a key role for design of labyrinths too. Hence, designing of the drum brakes for extreme heating is critical. This paper elucidates the thermo-mechanical behavior in two-wheeler drum brakes under extreme braking and their consequence manifesting itself in permanent distortions resulting in the brake failure. Experiments as well numerical simulations are carried out to investigate the thermo-mechanical behavior of drum brakes. Experiments are conducted at extreme braking for maximum thermal loading on the drum brake. The rise in temperature of the drum is measured with sensor. The generated heat energy causes

Singh, Om Prakash, Mohan, S., Mangaraju, Venkata, Babu, R.

Creating an Automated Brake Inspection System with Machine Vision

TBMG-1359106/01/2008

A Tier 1 automotive supplier of brake drum assemblies with customers here and abroad has tried a number of different vision systems for brake drum assembly inspection, but have had very limited success. The main problem with the previous systems was their dependence on using pattern matching, which proved inadequate in handling the wide variations and complexities in the assemblies.

Test Procedures for Shear Strength of Automotive Brake Pads and Brake Lining Assemblies

J840_200708 (Historical)

08/21/2007

Brake Linings Standards Committee

Analysis of Lining Assembly for Brake System

2006-01-354610/31/2006

This paper describes an analytical process for the design of a brake shoe assembly that consists of the linings, shoe table, webs, and rivets. One fundamental performance requirement for the brake shoe assembly is that the linings will not lose clamp force within the desired service life. Key elements of the analytical process involved developing an FEA model with given loading conditions and developing a mathematical model to study the influence parameters of the forces acting on the lining.

Cheng, Wangquan (Winston), Kuan, Scott, Shih, Shan

Evaluation of SAE J840 Lining Shear Test Procedure

2006-01-319110/08/2006

The SAE Brake Linings Committee launched an evaluation of the current SAE standard J840 “Test Procedures for Brake Shoe and Lining Bonds,” specifically the bond plane shear test. The aim of the study was to identify what settings in the shear test lead to the most repeatable results for a variety of linings. An initial four factor two-level design of experiments (DOE) was conducted, with 15 pads sheared for each condition. The DOE looked at pad material type (NAO and semi-metallic), backing plate attachment type (integrally molded and mechanical retention system), ram offset position (1.0 mm and 4.0 mm) and normal pressure (0 and 0.5 N/mm2). The test measured shear force and percentage material retention for each pad tested. The objective of the DOE was to guide revision of the SAE J840 shear test procedure. For example, the application of a normal force raises the nominal value of the shear force by 30-50%, and reduces the variability of the test results. Hence, the Committee will

Basch, Rena, Agudelo, Carlos, Millsap, Tom, Carter, Dave

Brake Performance Testing and Truck Runaway Analysis

2003-01-339611/10/2003

Commercial vehicle air brake systems are associated with more heat problems than hydraulic brake systems on passenger vehicles. A typical commercial vehicle runaway involves a driver who has lost the ability to control the speed of his vehicle and runs off the road because of too much speed in a curve or collides with slower moving vehicles. In some cases the driver has the ability to control speed to some extent and is unaware that he has overused the brakes until faced with a situation requiring a heavy brake application. The loss of braking capacity on long steep downgrades is due to the combined effects of heating, brake system design, friction material properties, maintenance, and brake adjustment. Brake drums expand as temperatures increase causing the strokes of the pushrods to increase. Brakes that are out of adjustment or at the limit of adjustment before heating can lose effectiveness with less heating than properly adjusted brakes. As trucks have been improved to reduce

Scott, John, Fay, Richard, Hoover, Norris, Robinette, Ric, Deering, Darrell

High Performance Drum Brake Assembly for Automotive Braking Applications

2003-01-330610/19/2003

Different types and sizes of hydraulic drum brake designs viz., two leading sliding shoe, leading-trailing sliding shoe, floating abutment sliding shoe are in existence today catering to the increasing vehicle weight applications. On an end requirement basis and by the cost benefit ratio, either of the above designs with appropriate brake size (diameter) is selected for a given vehicle application. Increasing wheel cylinder size and brake size proportional to the requirement also needs bigger actuation systems and poses packaging constraints within the available wheel sizes. A High performance drum brake assembly is developed from the basic hydraulic, leading-trailing, sliding shoe brake design, which can substantially increase the brake output torque for a given hydraulic input pressure or reduce the required pipeline pressure to realize the current rated torque. The brake assembly has a new lever pivoted on the leading shoe web with one end resting on the wheel cylinder piston and

Raajha, M. P., Narayanan, V. Lakshmi

Harmonization Activities on ISO and JIS Standards (Assembly Shear Strength) for Brake Linings in Japan

2002-01-259801/06/2002

A joint taskforce between the Sub-committee (Brake Linings) of the J-SAE and the Technical Committee (Brake Linings) of the JAPIA from 1999 through 2002 has been conducting actual test runs regarding “Assembly Shear Strength” based on ISO 6312 and JIS D 4422. The studies on “Assembly Shear Strength” for these standards are discussed in this paper and some considerable improvements for these test procedures have been obtained through these test studies and actual test runs. This joint taskforce issued two papers on the harmonization studies of ISO and JIS Standards on “Internal Shear Strength of Brake Linings” and “Compressibility of Brake Linings” at the 18th and 19th Annual Brake Colloquiums respectively. The results of the two studies and the present study are summarized jointly and discussed in this paper.

Sasaki, Yosuke, Kaido, Masataka

A Comparative Study on the Performance of Ventilated Brake Discs Manufactured in Different Advanced Materials

2001-01-332510/01/2001

Two different aluminium alloy materials have been used to produce ventilated brake discs, on one hand, AS17G0.6 hypereutectic alloy and on the other hand, AS7G0.6 reinforced with 20% in wt. of SiC particles. The casting production technique used has been Low Pressure Casting (LPC) and some of the brake discs have been heat treated using a T6 treatment. Once the ventilated brake discs were produced and machined, they were tested in a dynamometer in order to compare the performance under service conditions of the aluminum alloy and grey cast iron (GCI) discs currently used in the market.

Goñi, J., Mitxelena, I., Rubio, A., Coleto, J., Terrón, A., García, A., Sánchez, J.

The Kinetic Brake Booster

2001-01-318910/01/2001

Main defect of traditional structure of the brake boosters is the necessity of an external energy source. The analysis of redistribution of power streams occurring during at braking of the automobile shows that it is possible to use the force component of the driving automobile kinetic energy for the drive of a booster (so-called kinetic booster). The power consumed by a booster is taken from power developed during brake action thereby it promotes vehicle slowing down. In the paper for the booster work the schemas of power take-off from an engine, onboard electric system, transmission, single wheel are considered. Especially for brake-by-wire systems the project of pilot management is probed. It allows applying the serial x-by-wire components both on small automobiles andon vehicle with the great load-carrying capacity and trailers.

Ivanov, Valentin, Lepeshko, Joseph, Boutylin, Vladimir

Advantages of Gasar-Materials for Brake Shoes and Plates

2000-01-275610/01/2000

The high thermal conductivity is one of the most important properties of materials used for brake shoes and plates manufacture. Besides these materials should have a high friction coefficient, toughness and endurance. The metalplastic compositions are widely represented among the materials used now, however they have low heat conductivity coursed in limitation of transport driving capabilities. For the solution of this problem, we offer to apply recently created porous materials - gasars with monolithic metal matrix and cylindrical (or ellipsoidal) pores charged with abrasive powder. The tests have shown, that Gasar brake components have higher thermal conductivity and combine properties of solid metal and frictional material.

Shapovalov, Vladimir, Boyko, Ludmila

The Effect of Cu2S Solid Lubricant Addition, and Varying Density, on the Occurrence of Brake Squeals for One Low-Metal, Organic Type Brake Pad

1999-01-339410/10/1999

Brake pads with an especially formulated, low-metal organic friction material were tested in a rig especially developed for brake squeal tests. The effect on squeal generation by the addition of 0, 2, 4, 8 and 12 vol% Cu2S to the friction material was investigated. All tests were performed at low speeds, moderate to low brake pressures and with disc temperatures in the range of 70-270 °C. It was found that the addition of Cu 2S consistently reduced the number of generated squeals, with an optimum around 4-8 vol% addition. Further, the addition of Cu2S also lowered the coefficient of friction for the present friction material formulation. A friction minimum was obtained at 8 vol% Cu2S. Included in this investigation were three sets of pads, all containing 8% Cu2S, but with different densities. It was found that the pads with the higher density generated fewer squeals than did the pads with the lower density. Within the limits of the test, there was a definite trend for pads with higher

Bergman, Filip, Eriksson, Mikael, Jacobson, Staffan

Prediction of Damping Treatment Dynamics as Bonded to a Brake Shoe and Lining

1999-01-340710/10/1999

In this paper, a brake damper is modeled with the finite element method to predict its response in a free-free impact modal test. A multi-layer representation of a brake shim is described which captures the dynamic characteristics of a damper, bonded to a brake shoe and lining. Calculations of damping values and natural frequencies are compared to impact modal test results over a wide temperature range. It was found that the finite element model accurately predicts the results from the experiment. A discussion is also given on how the model may be used to develop a material database and automation of the modeling process to analyze any layered brake damper.

Mignery, Lezza A., Nashif, Ahid D.

The Development of a Temperature Alarm Device for Failure Prevention of the Automobile Hydraulic Brake System

1999-01-047403/01/1999

The pursuit of safer and more reliable car is the trend of modern automobile engineering. The major protection against an automobile accident is the brake system. However, to date, there is no safety device, which is designed to prevent failure from high temperature of the hydraulic brake system. In general, the brake force is generated from the friction between brake shoes and brake drums or disks. As the vehicle slows down, the moment of inertia of the vehicle is transformed into heat to raise the temperature of the brake system. The rapid rising of temperature may result in serious safety concerns of the brake system and its failure could be expected. The main purpose of this research is to develop a device, which can detect high temperature in the hydraulic brake system and provide a safety alarm before it fails. The device utilizes temperature sensors to monitor temperatures of the brake shoe lining and hydraulic fluid of the brake wheel cylinders. Both of the current temperatures

Lee, Shuo-Jen, Lin, Ke-Feng, Tai, Chi-Fu, Wu, Shih-Hsiung, Gau, Chung-Yun

Electronic Monitoring of Commercial Vehicle Outboard Brakes to Determine Out-of-Service Conditions

981895

08/11/1998

The International Border Electronic Crossing System (IBEX) incorporates low cost sensors on commercial vehicle braking systems to evaluate out-of-service conditions (OOS). OOS conditions include dragging, worn and inoperable brakes. Present roadside brake inspections require manual inspection under the vehicle to verify the operation and condition of the brake system components. To minimize these under-vehicle inspections, on-board sensors can monitor brake component conditions while the vehicle is in operation. Signal Processing Systems (SPS), Calspan Corporation, and Radlinski and Associates, Inc. (RAI) equipped three commercial vehicle tractors with brake shoe thermocouples and instrumented brake chambers. Brake condition data, acquired by the SPS “SmartLog” system, was recorded to a PCMCIA card and down-loaded on a weekly basis. Also recorded with the brake condition data was vehicle location at time of brake operation. This paper describes the design process resulting in the

Wilson, Glenn, Pierowicz, John, Coughlin, Tom