DrumThermal capacity and stiffness

Drum
Thermal capacity and stiffness are key parameters. Significant improvement in AMS performance has been achieved
by increasing thickness of the drum barrel. This has the dual benefits of increasing thermal capacity and increasing
drum stiffness. Some competitors (eg VW Lupo) specify deep stiffening rings to achieve the same objectives.
Cooling
Thermal capacity is important because of the short duration of the AMS test cycle, but good cooling can help keep
temperatures under control and also provides significant benefit in terms of pad and disc wear and brake fluid
temperature. Consider the following strategies:-
- Alloy wheels with good airflow can reduce disc temperatures compared to steel wheels with covers.
- Larger cooling holes, aligned with holes in the wheel, for plastic wheel covers.
- Air ducting from the front bumper to the wheel arch.
- Air vent slots in the wheel arch liner.
- Removal of front disc splash shield.
Caliper
High bridge stiffness and controlled seal roll back are important for good AMS performance. Pad area should be
large enough to withstand high clamp loads and maintain power absorption within recommended levels (see RVT
Brake Specification Sheet).
Rear Drum Brake
Rear disc brakes are required on all but the smallest vehicles for best-in-class stopping distance and AMS
performance. However, drum braked B/C class cars can achieve 40m stopping distances cold and hot with optimised
brake design. Auto-adjusters must be tuned to avoid excessive shoe centre clearances, which lead to high fluid
consumption and master cylinder bottoming out, without causing the brakes to bind when the drums cool.
Incremental adjusters must have a thermal cut-out feature to prevent over adjustment. Drum expansion should be
minimised for both ‘one-shot’ and incremental adjusters, to prevent binding in the former and excessive clearance
when hot in the latter.
Tyres
To achieve 40m stopping distance requires a fully developed deceleration of 1g – assuming an ABS efficiency of
95% (a good system) this requires a tyre to road friction level of at least 1.05. Testing has shown differences of 4 to
5m in stopping distance for different make and size of tyre. Comparative tyre testing should be part of the brake signoff
program if B-I-C stopping distance and AMS performance are objectives. Tyres benefit from ‘scrubbing in’ to
develop maximum performance.
ABS
To achieve below 40m stopping distance consistently throughout the AMS test requires near perfect front to rear
brake distribution. Even for a system well balanced at ambient temperatures, differential front-to-rear fade will mean
that balance is not perfect during the later stops. In addition, the driver must achieve peak deceleration right from the
beginning of each stop – this is difficult without ABS.
This means that to meet the 40m objective the vehicle must be fitted with 4 wheel ABS with electronic brake force
distribution (EBD) and no mechanical pressure control valves. This will allow the driver to apply high pedal efforts
and ensure maximum braking (ABS operation) from both axles from the beginning of stop. Both axles must be in
ABS control throughout each stop.
The ABS should achieve above 90% efficiency on both axles.

結果 (中文) 1:

滚筒热容量和刚度是关键参数。取得了 AMS 性能显著改善通过增加厚度的鼓桶。这已增加热容量和增加的双重优点滚筒刚度。一些竞争对手 (如大众 Lupo) 指定深加劲环来达到相同的目的。冷却热容量是重要的因为短期限的 AMS 的测试周期，但良好的冷却效果可以帮助保持温度控制下的还提供了显著的经济效益和垫和盘磨损和制动液温度。考虑以下策略:-合金车轮与良好的空气流通可减少盘温度相比钢车轮盖。-大冷却孔，与对齐孔在轮，胶轮首日封。-风从前保险杠到车轮拱。-空气通风槽轮拱衬砌结构。-去除前盘挡泥板。卡尺高桥梁刚度和控制的密封回滚是重要的 AMS 性能良好。焊盘面积应该是大到足以承受高钳负荷和维护推荐级别 (见 RVT 内的功率吸收制动规格表)。后轮鼓式制动器后轮盘式制动器被要求所有但同类最佳停车距离和 AMS 的小工具性能。但是，鼓式刹车 B/C 类汽车可以达到 40 米停止距离冷和热与优化制动器设计。必须调整自动调节器，以避免过度鞋中心间隙，导致高流体消费与主缸见底，而不会造成刹车要绑定时鼓冷却。增量调节器必须有热的裁剪功能，以防止在调整。应鼓扩大最小化的一次性和增量调节器，以防止前和过度的间隙中的绑定当热在后者。轮胎为实现 40 m 刹车距离需要 1 g — — 假设的 ABS 效率充分发展的减速95%(一个好的系统) 这就要求至少 1.05 路摩擦程度的轮胎。测试表明，差异为 45 米的刹车距离为不同生产日期和大小的轮胎。比较轮胎测试应该是制动签收的一部分如果 B-C 停车距离和 AMS 性能目标的程序。轮胎受益 '洗涤' 到发挥最大性能。ABS要实现刹车距离自始至终 AMS 的 40 米以下测试需要近完美从前到后制动分布。即使在环境温度下平衡系统，微分前端到后方淡入淡出会表示在以后停止过程中，这种平衡并不完美。此外，驱动程序必须实现从峰值减速从开始的每一站 — — 这是困难没有 ABS。这意味着，以满足 40 万目标车辆必须配备有 4 轮 ABS 电子制动力分配 (EBD) 和没有机械压力控制阀门。这将允许驱动程序适用高踏板努力并确保最大制动 (ABS 操作) 从两轴从站开始。这两个轴必须在在每一站的 ABS 控制。ABS 应达到对这两个车轴效率 90%以上。

結果 (中文) 3:

鼓的热容量和刚度是关键参数。在AMS性能得到显着的改善，通过增加鼓筒厚度达到
。这具有增加的热容量和增加的鼓刚度的双重好处。一些竞争对手（如大众Lupo）指定深度的加强圈来达到同样的目标。
冷却
热容量是重要的因为对AMS试验周期短，但良好的冷却可以帮助保持
温度下控制并提供显著的好处在垫盘磨损和制动液
温度。考虑以下策略：-有良好的气流的合金车轮可以减少盘的温度相比，钢轮与盖，在轮孔对齐，塑料轮罩。
-前保险杠的轮拱风。
-排气槽的轮拱。
-盘前挡泥板的去除。
卡尺
高桥梁刚度和控制密封滚回来好AMS性能很重要。垫面积应为大到足以承受高负荷和保持功率吸收夹在所推荐的水平（见RVT
制动规格表）。
后轮鼓式制动器
后盘刹都需要除了最小的车辆最好的停车距离和AMS
性能。然而，鼓式刹车B / C级车可以达到40m的制动距离，冷和热
制动器的设计与优化。自动调节器，必须避免过度的制鞋中心间隙，导致高液
消费和主缸见底，没有造成刹车鼓冷却时捆绑。
增量调节器必须具有热保护功能来防止过度调整。膨胀应
最小化为“一次性”的增量调节，为了防止在前和间隙过大时
热在后者的结合。
轮胎
达到40m距离需要成熟的1G–假设95%
ABS效率减速（一个好的系统）需要一个轮胎至少1.05路摩擦的水平。测试显示差异4
5m距离和大小不同的轮胎。比较轮胎的测试应该是制动签收
计划的一部分，如果b-i-c停车距离和AMS性能目标。轮胎受益于'洗涤'
发展最大的性能。
ABS
达到40m以下的停车距离整个AMS测试需要近乎完美的前后
制动分配。即使在环境温度下平衡系统，差前到后褪色将意味着，平衡是不完美的，在以后的站。此外，司机必须实现从
开始每一站–这困难没有ABS峰减速吧。
这意味着达到40m目的车辆必须装有4轮ABS和电子制动力分配（EBD）和
没有机械压力控制阀。这将允许司机应用高踏板的努力，并确保从两个轴的最大制动（ABS操作）从两个轴的停止。这两个轴必须在每一站都有一定的控制，在这两个轴上，ABS应达到90%以上的效率。