Book Description

To assess the strength and durability for hydraulic brake components as a function of test conditions. These conditions may include: braking torque, hill-holding, braking forces, hydraulic pressure, brake temperatures, environmental and corrosion effects, vibration, and time. This RP includes a systematic reference to other test methods and provides new test methods for durability life prediction based on the VDA 311 for operating strength for brake calipers. When using AK load collectives from vehicle testing for life prediction, the nominal vehicle life corresponds to 300000 km. Braking torques and forces take into account inputs from non-ABS, ABS, EPB, and ESC systems. It also applies to gasoline, diesel, hybrid, and electric vehicles. This RP applies to vehicles below 4540 kg of GVWR. With the appropriate engineering review and assessment for a given test program, this RP can apply (or be used) to scale the duty cycle (or special collective) to reflect regional, on-road special applications, or vehicles up to 7 tons of GVWR.Except for the AK load collectives, which have proven correlation to customer usage, the damage content of other procedures requires (a) the quantification with actual laboratory testing to develop the corresponding S/N curves, and (b) the calculation of the equivalent damage at the test conditions for a given load collective.The hydraulic components covered by this RP include: aNon-vacuum apply system (brake booster and master cylinder) bABS modules cService, IPB, and EPB calipers dProportioning valves eWheel cylindersThis RP has an accompanying electronic appendix with the tabular presentation as a spreadsheet of different test procedures by type and by component. The globalization of vehicle architectures and platforms demands a global basis for testing methods and standards. The trend towards vehicles which meet performance requirements in different regions, benefits from a Recommended Practice (RP) which organizes multiple test methods for hydraulic components. This organization is critical to the success of the vehicle program, including the overall quality, reliability, cost-effectiveness, and safety of the vehicle.To remain competitive and relevant, the development of hydraulic brake components needs to relate to vehicle usage. This correspondence or correlation ensures product design, performance, and overall durability and reliability are a flow down from vehicle-level conditions and relate to an expected vehicle or component life or warranty period. To enable the translation of vehicle-level load collectives to component-level pressure and torque levels, a flowchart is provided as a guidance to conduct such conversion and calculations. To assist test programs without vehicle- or application-specific parameters, this RP provides vehicle weights, dimensions, and brake system parameters for several vehicles covering classes A-to-H from the U.S. Code of Federal Regulation (CFR), Part 565.The task force would like to give special recognition to the work conducted in Europe regarding load collectives and the corresponding statistical treatment. This work was made available as a direct contribution from several Original Equipment (OE) and tier-1 brake suppliers to this RP. In addition, the work and experience of task force members and their companies provides sufficient evidence to support the minimum cycles indicated as performance requirements. These requirements are already used by multiple vehicle manufacturers and brake suppliers as part of their test plans on multiple production programs. When testing in accordance to this RP, product service life is predicted to be 300000 km for regular street usage of a 99th percentile driver.