Browse Topic: Brake shoes

Items (132)

Air Brake Performance and Wear Test Code Commercial Vehicle Inertia Dynamometer

J2115_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

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

J3006_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

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

2017-01-25359/17/2017

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 temperature decreases by 69.9°C and reaches 193.1°C after the heavy truck goes down the chosen slope with the combined braking strategy. The brake thermal decay of the brake drum could be avoided and the brake safety could be ensured after using the combined hill descent braking strategy.

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

The Effect of Commercial Vehicle Head-Up Display Reminding System on Driving Safety in Mountainous Area

2017-01-25009/17/2017

Head-up Display (HUD) system can avoid drivers’ distraction on dashboard and effectively reduce collisions caused by emergency events, which is gradually being realized by researchers around the world. However, the current HUD only displays information like speed, fuel consumption, other information like acceleration and braking can’t be displayed yet. This research will use the indicator symbol‘s color and position change to remind drivers to brake or accelerate. Drivers can do driving operation timely and accurately. The system has the advantages of safety, intuition and real-time. The vehicle safe speed is calculated according to the road parameters, like adhesion coefficient and slope, and vehicle parameters, such as vehicle mass and centroid. Then, the appropriate braking operations are obtained by combining the vehicle driving state. The braking information is corresponded to the color and position change of the indicator symbol to prompt the drivers by the HUD interface. At the same time, under different driving conditions, experiments will be carried out to find out the difference of driver’s braking operations when there is braking information presentation or there is not. The effects of different braking operations on driving safety performance will be evaluated. Compared with the condition of no braking information presentation, braking information presentation can make the start braking time ahead of schedule. In addition, the emergency braking situation will be reduced appropriately. The results show that the braking information presentation based on the HUD system has significant effects on improving driving safety.

Huang, Bo, Xia, Wanyang, Tan, Gangfeng, Xiao, Longjie, Wang, Zongsong

Experimental Study of Howl Noise Phenomenon Related to Drum Brake Squeal

2017-36-00075/24/2017

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.

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

2016-01-19139/18/2016

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, a potential drop of the emitted pollutants coming from the high-temperature degradation of organic resins. In the present work the results of our investigation in the field are illustrated, our prototype inorganic material is indeed compared to the original resin-based OE and to another traditional phenolic alternative. Brake pads were tested on a full-scale automotive brake dynamometer, following SAE J2522 (AK Master) procedure. In order to prove the excellent performance of such inorganic materials even under high-demanding conditions, brake pads were also tested by means of an internal fading procedure. The results obtained so far are promising and pave the way to further developments toward a concrete industrialization of these unconventional class of friction materials.

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

Test Component Specifications

J1802/1_201607 (Current)7/27/2016

Truck and Bus Foundation Brake Committee

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

2015-01-26669/27/2015

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 over after the pad is assembled, compromising paint adhesion. Manufacturers using black steel shot blast the disc brake shoes after stamping, attempting to remove mill scale. Shot blasting can deform/compromise critical shoe dimensions causing fit, function, and safety issues in the caliper assembly. GBSC studied randomly selected leading aftermarket brands to further analyze the above mentioned disc brake pad failures and the effects of black steel. Parts were put through a 96 hour salt spray test in which the brake shoe must meet 5% red rust maximum. All painted brake shoes failed before the 20 hour interval. The only pad sets to meet the rust requirements had zinc coated shoes. Upon inspection, almost all pad sets showed out of tolerance measurements in critical areas. Sections of some brake pads, black steel samples, and suspected black steel pads, were prepared and examined using ASTM metallographic procedures. Scale was embedded in the black steel samples and in the bond layer of suspected black steel pads. No iron oxides found in pads with shoes made from pickled/oiled steel. GBSC recommends all disc brake shoes be manufactured using pickled and oiled steel.

Lambert, Scott

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

2014-01-25059/28/2014

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, which has met all the performance in competitive price. In Conventional disc brake system, brake rotor has hat type construction which is complicated considering design complexity and takes higher manufacturing lead time. Innovative concept of front disc brake (Patented by Tata Motors) with straight brake rotor was evolved and later on designed with respect to packaging constraint. Number of manufacturing steps for this brake disc rotor is drastically reduced, resulted in less manufacturing time with cost & weight reduction. Digital thermal performance evaluated in house, fine-tuned and verified by correlating with test data available for existing design and then applied for new design.

Shah, Ashesh, Patil, Sanjay, Abhyankar, Umesh

Hydraulic Wheel Cylinders for Automotive Drum Brakes

J101_201307 (Current)7/9/2013

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)4/9/2013

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

2013-01-04934/8/2013

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)2/13/2013

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

2012-01-18979/24/2012

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 the full nonlinear one is presented. Both the full nonlinear model and the reduced order model show that increasing in the brake pad wear level increases the pressure spikes dynamics at the contact surface between brake pad and rotor disc and hence could leads to brake squeal and shortens the braking pad service life.

Haggag, Salem A., Abidou, Diaa

Hot Powder Preform Forging Technique for Making Brake Pad

2011-28-007610/6/2011

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 pressing, and, wide variations in final characteristics due to large number of variables involved. Besides above, cost of raw material and consumables along with heavy capital equipments makes this technique costly and only large scale production is possible where these costs are distributed in the large volume of production. In contrast to these limitations, the present technique can offer brake pads of much simpler chemistry but with improved performance on account of simultaneous application of pressure and temperature and with better control of variables.

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

The Effect of Metal Pickup to the Friction Interfaces

2011-01-23489/18/2011

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. Observations on results of such experiments were described and several working hypotheses put forward with influences going back to the brake rotors metallurgy and surface finish as well as to the friction materials ingredients. This paper gives an overview to the actual situation of the research and developments about the effect of metal pickup generation. An investigation of a multitude of MPU cases from real car driving is used to cluster and structure the principal phenomena and discuss the various aspects. The discussion of the experimental results and the previous findings, lead to a new experimental set up which is proposed for further investigation and future works. This shall lead to a better way of investigating and understanding the influencing parameters within the brake system, rotor and brake lining for their effect to the phenomena.

Lange, Jürgen, Ostermeyer, Georg

Test Component Specifications

J1802/1_201105 (Historical)5/16/2011

Truck and Bus Foundation Brake Committee

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 shoe under braking. Test result showed that the SPL of the brake squeal was reduced at significant peak of SPL around 700Hz when the disc had large diameter holes on the frictional surface. The stability analysis also showed that the stable region was extended when large hole was opened on the disc. The excitation force estimated by FE and FDTD model of the shoe was reduced when the diameter holes was increased. These results indicated that the excitation force at brake squeal was prevented by the modification of strain distribution. Such discussion was experimentally confirmed by the bench test with modified shoes which had concentrated strain distribution. This paper proposed an effective concept to prevent the squeal of the brake disc for motorcycles.

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

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 structural characterization of brake friction material. Finally the results are discussed and correlated to the observed friction phenomenon. The coefficient of friction was found to be highest for Grade B and lowest for Grade A and wear of Grade A was lower than that of grades B and C. It was observed that the coefficient of friction increases with increase in speed from 8.34 m/s to 22.23 m/s and then it continuously decreases for speed up to 38.89 m/s. The maximum coefficient of friction was observed at a speed of 22.23 m/s for all the grades viz. A, B and C.

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

Complex Mode Analysis on Disc Brake Squeal and Design Improvement

2009-01-21015/19/2009

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 without shim shows that with the damping layer, both the noise occurrence and sound pressure level are much lower in the frequency range between 1000∼18000Hz.

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

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

2009-01-02164/20/2009

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 better performances than the parts made with the existing higher cost chemistry.

Huang, Yanjun

An Investigation of Container Chassis Brake Lining Maximum Wear Rates

2009-01-00914/20/2009

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

Effect of Thermo-Mechanical Behavior on Drum Brake Labyrinth Design

2008-32-00669/9/2008

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 brake drum to expand both in lateral and radial directions. Under extreme braking condition rubbing of brake drum with brake panel is observed in the case of low clearance between drum and panel. Hence it is important to design the drum braking system taking extreme thermal loading into consideration. At design stage it is essential to predict the proper clearances and dimensions of the drum brake for better thermal performance and safety. Numerical simulations are conducted to predict the thermal behavior of drum brakes under severe braking condition. Finite element analysis has been performed with commercially available software. Thermal expansion comparisons are made between spoke wheels and alloy wheels. The simulation method is useful for design validation of the drum brake system upfront of the product development.

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

Creating an Automated Brake Inspection System with Machine Vision

TBMG-135916/1/2008

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)

8/21/2007

Brake Linings Standards Committee

The Freight Train Emergency Brake System and a Method to Calculate Stop Distance and Time

2007-01-07214/16/2007

Determining the arrival time for a freight train at a railroad crossing and how the train engineer could affect the arrival is a common question. This paper discusses the freight train brake system, the freight train makeup variables and considerations, and a method to calculate the freight train brake to stop time and distance. The pneumatic brake system, AB brake valve, air propagation rate, braking ratios, braking efficiencies, wheel/shoe adhesions, and the brake system development times are addressed. With the ability to calculate the change in speed, the freight train change in arrival time at a crossing can be determined.

Bentley, John M., Bentley, John

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

2006-01-319110/8/2006

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 recommend incorporating normal force application for disc brake pads. This paper will present the results of the factorial DOE with resolution IV (8 trials, 4 two-level factors, 15 repetitions) and the proposed revisions to the standard.

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

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 the other end on the strut assembly. This lever touches the piston instead of the leading shoe web and receives input from the pressurized wheel cylinder. Upon actuating the wheel cylinder assembly, the lever rotates about its pivot point and pushes the strut assembly. The trailing shoe now receives two inputs viz., one from the wheel cylinder and the other from the strut assembly, which is mechanically actuated by the new lever. The reaction from the trailing shoe is passed via the strut assembly as an input to the leading shoe. The wheel cylinder input and the strut reaction force together acting on the pivot, results in almost twice the force acting on the leading shoe. Prototype samples incorporating the new design is developed and validated on inertia dynamometer.

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

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

2002-01-25981/6/2002

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

The Kinetic Brake Booster

2001-01-318910/1/2001

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

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

2001-01-332510/1/2001

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.

Advantages of Gasar-Materials for Brake Shoes and Plates

2000-01-275610/1/2000

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

An Analytical Method to Predict Thermal Distortion of a Brake Rotor

2000-01-04453/6/2000

The severe thermal distortion of a brake rotor can affect important brake system characteristics such as the system response and brake judder propensity. This paper will propose a technique to determine the thermal distortion under transient or steady state conditions. The technique involves utilizing a PC-based computer program to calculate the necessary thermal parameters and apply the results as input to a finite element-based thermal stress analysis. This unique approach provides a reliable methodology to determine the heat input and cooling characteristics of a given brake system in addition to resultant distortion and stress components within the brake rotor. Analysis results are also compared to measured temperature and distortion data.

Valvano, Thomas, Lee, Kwangjin

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 friction to generate more brake squeals.

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

1999-01-04743/1/1999

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 are checked with alarm control parameters. When either one of the temperatures exceed the preset value, the control unit will send an alarm signal to warn the driver who should then take precaution and/or prevention actions

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

8/11/1998

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 specification of the sensors installed on the tractors and includes examples of the data collected. The data validates automatic monitoring of brake OOS conditions with the IBEX system and demonstrates OOS information can be provided to the inspector without an under-vehicle visual inspection.

Wilson, Glenn, Pierowicz, John, Coughlin, Tom