本SAE推荐规程旨在作为标准试验的定义，该标准试验可能会频繁变化，以跟上经验和技术进步的步伐。在考虑其用途时，应牢记这一点。 SAE 2号摩擦测试监测µ-v曲线的负斜率，可用于评估湿式离合器系统（WCS）的抗抖动性能，并可用于任何湿式传动系统机构。WCS抖动被认为是离合器故障情况。抖动的原因与玻璃作为主要故障模式一致。已经表明，湿摩擦材料表面孔隙率的显著损失导致摩擦材料表面上形成釉。 该过程通常会导致SAE 2020-01-0560中所述的随时间推移的负dµ/dv斜率。 该程序包括评估湿式离合器系统（WCS）在各种特定压力、速度和温度下的摩擦特性，以及延长耐久性占空比测试，以评估WCS，在该测试过程中，监测µ-v曲线的负斜率，这表明存在抖动的可能性。 该程序可用于比较摩擦材料和润滑剂的各种WCS组合的抖动可能性。建议在SAE 2号或类似机器上进行测试。 在比较结果时，所有测试也使用同一台机器。老化量与车辆行驶里程或车辆抖动无关，只能作为µ-v测试中出现严重负斜率的测试示例。 本程序适用于具有一个摩擦片和两个钢板的标准SAE盘式离合器组件，但可针对任何WCS配置进行修改。 本程序以SAE J2964为基础，修改了测试参数和测试程序，以评估WCS老化稳定性并预测抗抖动性能。 本程序旨在作为供应商和最终用户的推荐做法。 摩擦系统供应商或用户选择的唯一变量是: •带摩擦材料的摩擦片（内衬）:指定摩擦材料、批号或批号、凹槽图案和内衬厚度。•流体:指定流体和批号。•反应（分离器）板:使用SAE标准，如下所示。指定板材材料、厚度和批号。 在报告测试结果时，必须明确确定这三个变量。如果本文件中所述的任何测试参数或系统硬件发生了变化，而非摩擦材料、测试流体或反应（分离器）板，则可能不会报告使用本文件获得的数据，但应显示为程序的修改版本。 摩擦测试有多种模式，包括短时连续滑移（C）、斜坡上升和下降速度扫描（S）以及静态或分离滑移（BA）。摩擦测试在磨合前（BBI）、磨合后（ABI）和每个老化试块（A）之后进行。该测试程序的总体概述如图1所示。 参考表1所示的试验离合器几何参数。 在不同模式下，使用不同的测试速度、流体温度、装置表面压力和滑移正时来模拟离合器操作条件。 选择老化模式测试参数以在120小时的总时间内加速WCS退化响应。 获得的摩擦扭矩值和产生的摩擦系数、摩擦系数斜率（梯度）、流体和反应板温度允许比较WCS的耐磨性和抗老化性。这些参数用于评估离合器防抖性能。 第5节详细介绍了测试模式操作条件。

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. This SAE No. 2 friction test monitors the µ-v curve for a negative slope which can be used to evaluate a wet clutch system (WCS) anti-shudder performance and can be used for any wet driveline mechanism. WCS shudder is considered a clutch failure condition. The cause of shudder is consistent with glazing as the primary failure mode. It has been shown that a substantial loss of the wet friction material surface porosity leads to a glaze forming on the friction material surface. This process typically leading to a negative dµ/dv slope over time as addressed in SAE 2020-01-0560. This procedure includes evaluation friction characteristics of wet clutch system (WCS) at various specific pressures, speeds, and temperatures, and an extended durability duty cycle test to evaluate the WCS during which the µ-v curve is monitored for a negative slope—a condition indicating the potential for shudder. This procedure can be used to compare the shudder potential of various WCS combinations of friction material and lubricant. It is recommended that testing be conducted on an SAE No. 2 or similar machine. Also use the same machine for all tests when comparing results. The amount of aging has not been correlated to vehicle mileage or vehicle shudder and should only be used as an example of a test that results in a severe negative slope on the µ-v test. This procedure is designed for a standard SAE plate clutch pack with one friction plate and two steel plates, but can be modified for any WCS configuration. This procedure is built on the basis of SAE J2964, with modified test parameters and test procedure to evaluate a WCS aging stability and predict anti-shudder performance. This procedure is intended as a recommended practice for both suppliers and end users. The only variables selected by the supplier or user of the friction system are: • Friction plate with friction material (lining): Specify friction material, lot or batch number, groove pattern, and lining thickness.• Fluid: Specify fluid and lot or batch number.• Reaction (separator) plates: Use SAE standard as indicated below. Specify plates material, thickness, and lot or batch number. These three variables must be clearly identified when reporting the results of this test. If any of the test parameters or system hardware as described in this document are changed—other than the friction material, test fluid, or reaction (separator) plates—the data may not be reported as being obtained using this document, but should be shown as a modified version of the procedure. The friction testing has a combination of modes, including short time continuous slip (C), ramp up and down speed sweeps (S), and static or breakaway slip (BA). The friction testing is done before break-in (BBI), after break-in (ABI), and after each aging test block (A). The general overview this test procedure is presented schematically in Figure 1. Reference the testing clutch geometric parameters are shown in Table 1. Various testing speeds, fluid temperatures, unit surface pressures, and slip timings are used during the different modes to simulate clutch operating conditions. The aging mode test parameters are selected to accelerate the WCS degradation response within the 120 hours total time. The obtained values of friction torque and resulting friction coefficient, friction coefficient slopes (gradients), fluid, and reaction plate temperatures allow comparison of the WCS wear resistance and resistance to aging. These parameters are utilized for evaluating the clutch anti-shudder performance. Details of the test modes operating conditions are presented in Section 5.