Browse Topic: Brake drums
This SAE Recommended Practice establishes a standard method to perform screening test sequences that identify a brake friction material’s effectiveness under various test conditions. The result is an evaluation of brake friction material effectiveness under a set of defined braking conditions considered most relevant to automobile braking system development
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
This SAE Recommended Practice is intended for qualification testing for brake drums used on highway commercial vehicles with air brakes using an inertia-dynamometer procedure. This document consists of two distinct tests: Part A, durability and speed maintenance test, and Part B, heat check drag sequence test. Each test can be considered to be an independent evaluation of the brake drum which tests different properties
This SAE Recommended Practice is intended for measuring the static brake torque performance of a pnuematically actuated brake assembly, friction material, and drum/disc combination on an inertia brake dynamometer
The SAE J2521 procedure applies to high-frequency squeal noise occurrences for on-road passenger cars and light trucks below 4540 kg of GVWR. The procedure incorporates high-temperature and low-temperature test matrixes but does not fully account for the effects of the environment on brake squeal. For this test procedure, squeal occurs when the peak noise level is at least 70 dB(A) between 1.25 kHz and 16 kHz for tests using full suspension corners or full axle assemblies or between 2 kHz and 16 kHz for brakes not using a full suspension corner. Before using this recommended practice for chassis dynamometer testing, review in detail the specifics related to at least (a) instrumentation, including in-cabin microphones, (b) threshold levels for noise detection, (c) temperature control priority between the front and rear axles, (d) vehicle loading and load distribution, (e) cooling air and environmental conditioning, and (f) detailed nomenclature and labeling of channels and sensors
In Brazil, 20% of the accidents involve commercial vehicles, the high load capacity and the big dimension of commercial vehicles, such bus and trucks, become this situation even more dangerous. To prevent crashes, robust parts and product validation methodologies are essential for a safer and cheaper transport. The drum brake is widely used in commercial transport, due to the cheaper cost of production. The disadvantage of the drum brake system it’s his low thermal dissipation, to decrease the vehicle velocity, the brake converts kinetic energy in thermal energy, causing loss of efficiency, degradation of material mechanical properties and life reduction, these thermal effects can be even more dangerous under extreme conditions, as overload, speeding, over adjustment (dragging), and bad system maintenance. Due the fact that the temperature affects significantly the vehicle performance, especially in drum brakes system, the friction pair is tested under the worst road scenarios
This SAE Recommended Practice establishes a method of testing the structural integrity of the brake system of all new trucks, buses, and combination vehicles designed for roadway use and falling in the following classifications: a Truck and bus: Over 4500 kg (10000 pounds) GVWR b Combination vehicle: Towing vehicle over 4500 kg (10000 pounds) GVWR The test consists of two distinct tests: a structural endurance test followed by a structural ultimate strength test. NOTE: These two tests originated from separate procedures, and were combined in this recommended practice. Each test can be considered to be an independent evaluation of the service brake’s structure. Based on time available, cost limitations, and the desired evaluation and historical data available, either of these tests could be considered as a complete evaluation of the brake’s structure
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
This SAE Standard applies to self-propelled, rider operated sweepers and scrubbers as defined in SAE J2130 with maximum machine level surface speeds up to 32 km/h. Machines capable of speeds equal to and greater than 32 km/h are not covered by this document
This SAE Recommended Practice (RP) specifies a dynamometer test procedure to characterize wear rates of automotive service brake linings (brake shoes) and disc brake pads
This SAE Recommended Practice provides uniform laboratory procedures for fatigue testing of wheels for demountable rims and hubs intended for normal highway use on trucks, buses, truck trailers, and multipurpose passenger vehicles. The hubs included have bolt circle diameters ranging from 165.1 to 335.0 mm (6.500 to 13.189 inches). It is up to each hub and/or wheel for demountable rims manufacturer to determine the appropriate test method, accelerated load factor and cycle life requirements applicable to obtain satisfactory service life for a given application. When deviations from the procedures recommended herein are made, it is the responsibility of the hub and/or wheel for demountable rims developer to modify other parameters as necessary to ensure satisfactory service life for the intended application. It should be noted that this test procedure focuses on fatigue resulting from vehicle loading and cornering forces. It does not consider loads imparted to the hub from braking
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
When driving in mountainous areas, vehicles often encounter long downhill sections. Due to the large mass of bus and the drum brake with poor heat dissipation effect, it is easy for bus to produce braking thermal decay in long downhill section, which makes the vehicle out of control and causes safety accidents. The braking methods of parallel hybrid electric bus include drum braking, engine braking and regenerative braking, whose torque models are established in this paper. The coasting test in Trucksim is used to verify the correctness of the engine braking torque model. Based on coupling braking torque curve with vehicle speed in different gradient, the stable speed is determined and the shift strategy is proposed. The temperature rise model of brake drum is established to analyze the temperature change of brake drum during long downhill. Then, according to the ramp data of G22 freeway, the above models are simulated. The results show that shift strategy can make full use of engine
To maintain the vehicle speed in a proper range, the commercial vehicle needs to brake frequently on a downhill path. The drum brake system of the medium- and heavy-duty commercial vehicles often faces the danger of brake fade, which reduces brake efficiency or even causes braking failure. They are critical potential risks on the road. The kinetic energy is transferred into thermal energy during the braking process. The temperature rises dramatically during the braking process due to the massive thermal energy caused by the huge mass of the commercial vehicle. The brake efficiency and the life of the brake drum will decrease with the rising temperature. A malfunction of the brake system may occur if the drum brake is overheated. To improve the cooling efficiency of the drum brake, a forced-air cooling system driven by the air compressor in the diesel is designed for the drum brake system after the analysis of its thermal model. A computational fluid dynamics (CFD) model is established
This SAE Recommended Practice is intended for testing of external automatic brake adjusters as they are used in service, emergency, or parking brake systems for on-highway vehicle applications
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
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
This Aerospace Information Report (AIR) is intended to be concerned with fleet programs rather than programs for individual units. Technical and administrative considerations in developing an approach to a program will be suggested. Organization of material possibly wanted in the form of a detailed specification for airline rebuilder communication is reviewed
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
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
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
This SAE Recommended Practice establishes dimensions and tolerances for the interface between inboard mounted disc brake rotors and disc wheel hubs. This document is intended for inboard mounted disc brake rotors and disc wheel hubs for Class 5, 6, 7, and 8 commercial vehicles. Special and less-common applications are not covered
This SAE Recommended Practice provides the test procedure and methods to calculate the effectiveness of brake blocks, using an inertia dynamometer. To minimize testing variability, and to optimize standardization and correlation, a single, high volume size of brake block is specified (FMSI No. 4515E) and evaluated in a reference S-cam brake assembly of 419 mm x 178 mm (16.5 in x 7.0 in) size, using a specified brake drum
This SAE Standard applies to machines as defined in Appendix A. Some of these machines can travel on-highway, but function primarily off-highway
Subject document is specifically intended for service brakes and service brakes when used for parking and/or emergency brakes (only) that are commonly used for automotive-type, ground-wheeled vehicles exceeding 4536 kg (10000 pounds) gross vehicle weight rating (GVWR). Subject specification provides the off-vehicle procedures, methods, and processes used to objectively determine suitability of tactical and combat ground-wheeled vehicle brake systems and selected secondary-item brake components (aka, aftermarket or spare parts), including brake “block” for commercial applications only, specifically identified within subject document. Subject specification is primarily based on known industry and military test standards utilizing brake inertia dynamometers. Targeted vehicles and components include, but may not be limited to, the following: a Civilian, commercial, military, and militarized-commercial ground-wheeled vehicles such cargo trucks, vocational vehicles, truck tractors, trailers
This Recommended Practice is derived from the FMVSS 105 vehicle test and applies to two-axle multipurpose passenger vehicles, trucks, and buses with a GVWR above 4540 kg (10000 pounds) equipped with hydraulic service brakes. There are two main test sequences: Development Test Sequence for generic test conditions when not all information is available or when an assessment of brake output at different inputs are required, and FMVSS Test Sequence when vehicle parameters for brake pressure as a function of brake pedal input force and vehicle-specific loading and brake distribution are available. The test sequences are derived from the Federal Motor Vehicle Safety Standard 105 (and 121 for optional sections) as single-ended inertia-dynamometer test procedures when using the appropriate brake hardware and test parameters. This recommended practice provides Original Equipment Manufacturers (OEMs), brake and component manufacturers, as well as aftermarket suppliers, results related to brake
Brake drum in commercial vehicles is very important aggregate contributing towards major weight in brake system module. The main function of brake drum is to dissipate kinetic energy of vehicle into thermal energy, as a results in braking operation major load comes on brake drum. Hence this is very critical component for vehicle safety and stability [1]. Objective of this paper is to increase the pay load, which is utmost important parameter for commercial vehicle end customers. To achieve the light weighing target, alternate materials such as Spheroidal graphite iron (SGI) has been evaluated for development of brake drum. Many critical parameters in terms of reliability, safety and durability, thickness of hub, wheel loading, heat generation on drum, manufacturing and assembly process are taken into consideration. The sensitivity of these parameters is studied for optimum design, could be chosen complying each other’s values. Digital thermal performance evaluated in house, fine-tuned
In developing countries, motorcycles have become the most economically efficient choice for commuting. A variety of braking systems in motorcycles like Brake drum and Disk brake have once again become the deciding criteria for wise economic selection of a motorcycle. Due to the low cost of a brake drum compared with a disk brake, a median income group customer segment commonly prefers to buy the brake drum versions rather than disk brake. However the performance of the brake drum is inferior to the disk brake. One major inferior performance feature is brake fade. For a target customer segment, it always becomes a challenge for OEMs to provide the desired braking at sufficiently low costs for customers of that segment, while with the drum braking system, usually the user ends up with loss of brake effectiveness due to overheating, which in turn is produced by repeated braking actions. In this paper, a methodology to minimize brake fade was devised. By redesigning the brake drum (BD) for
This SAE Standard covers the hardness, tensile strength, and microstructure and special requirements of gray iron sand molded castings used in the automotive and allied industries. Specific requirements are provided for hardness of castings. Test bar tensile strength/Brinell hardness (t/h) ratio requirements are provided to establish a consistent tensile strength-hardness relationship for each grade to facilitate prediction and control of tensile strength in castings. Provision is made for specification of special additional requirements of gray iron automotive castings where needed for particular applications and service conditions. NOTE—This document was revised in 1993 to provide grade specific t/h control. In 1999 the document was revised to make SI metric units primary. To better align the grading system with long established production methods and grades produced, the previous system of grading by fixed combinations of tensile strength and hardness was changed in 1999 to a system
This SAE Recommended Practice is intended for qualification testing for brake drums used on highway commercial vehicles with air brakes using an inertia-dynamometer procedure. This Recommended Practice consists of two distinct tests: Part A - durability and speed maintenance test, and Part B - heat check drag sequence test. Each test can be considered to be an independent evaluation of the brake drum which tests different properties
Brake system is the most important system in the vehicle considering the overall vehicle safety and speed control. Brake applications are repetitive during a city traffic and hilly terrain on downhill gradient. Frequent braking gives rise to an overheating of the brake drum and its components. Braking operations at high temperature gives rise to problems like reduced deceleration due to loss of brake pad friction characteristics, pad softening and sticking to drum, pad distortion and wear etc. All these factors collectively result in deterioration of the braking performance and reduction of brake pad durability with time. Till date most of the thermal analysis performed for brake drum heating are through physical testing using brake system prototypes and by means of CFD tools. These methods are time consuming and expensive. There is a need for an alternative method to reduce physical trials and prototype building and reduce dependency on CFD analysis. The present paper focuses on
Overheating in commercial vehicles, even though if it’s in LCV segment, is a problem of high significance. There could be various level of problems that may arise due to heat generation resulting from braking (oversized brake drums left the wheels with lesser packaging clearances for air flow and cooling) and some of them are: 1. Early tire wear /reduction in tire life, 2. Air valve heat damage /air leak issues, 3. Frequent puncture problems, 4. Failure of other mating components and other heat initiated failures. However optimum the vent hole shape in a wheel may be, the air flow in the vicinity of drum periphery and wheel rim ID wouldn’t be sufficient enough because of the lesser clearance and packaging space as mentioned earlier. The basic construction of a wheel with disc welded to rim base ID was apparently modified to integrate the disc and gutter and weld it to rim OD. This provides additional 8mm clearance with a normal brake drum and hence effective heat dissipation from the
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
This specification covers general design and performance requirements for the mobility of towed ground support equipment. The complete mobility requirements for an item of towed aerospace ground equipment not specified herein shall be specified in the individual equipment specification (see 6.4
This SAE Recommended Practice establishes a method of testing the structural integrity of the brake system of all new trucks, buses, and combination vehicles designed for roadway use and falling in the following classifications: a Truck and Bus—Over 4500 kg (10 000 lb) GVWR b Combination vehicle—Towing vehicle over 4500 kg (10 000 lb) GVWR The test consists of two distinct tests: a Structural Endurance Test followed by a Structural Ultimate Strength Test. NOTE—These two tests originated from separate procedures, and were combined in this Recommended Practice. Each test can be considered to be an independent evaluation of the service brake’s structure. Based on time available, cost limitations, and the desired evaluation and historical data available, either of these tests could be considered as a complete evaluation of the brake’s structure
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