Wheel bearings play a crucial role in ensuring the smooth and reliable rotation of wheels in automotive applications. Grease is commonly used as a lubricant in wheel bearings. The physical properties of grease, such as viscosity, base oil type, and thickener composition, significantly influence the overall performance and longevity of wheel bearings. This study investigates the impact of grease's physical properties on wheel bearing friction torque and service life. To evaluate the effects of different grease formulations, a series of experiments were conducted using a four-ball tester, rheometer, and a custom-built test rig to measure bearing frictional torque and service life. Multiple greases with varying viscosity grades, base oil types (mineral oil, synthetic oil), and thickener compositions (lithium, diurea, and polyurea) were tested under controlled operating conditions. Friction torque measurements were obtained using a high-accuracy torque sensor, while service life was determined by monitoring the bearing life in actual endurance testing. The results indicated that grease physical properties directly affected wheel bearing friction torque and service life. Low to Medium-viscosity greases generally exhibited 35–40% lower friction torque due to enhanced lubrication film formation and reduced metal-to-metal contact however, excessively high viscosity resulted in 50–60% higher frictional torque and thereby increased energy consumption. Different base oil types showed varying friction reduction and service life level, with mineral oil in some cases showed lower frictional torque around 30–40% particularly at high temperature but with significant reduction in the service life. Furthermore, the thickener composition significantly influenced grease performance. Based on these findings, selecting the appropriate grease with optimal physical properties is crucial for minimizing friction torque and extending the service life of wheel bearings.

中文翻译：

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润滑脂物理性能对车轮轴承摩擦力矩和使用寿命的影响

车轮轴承在确保汽车应用中车轮平稳可靠的旋转方面发挥着至关重要的作用。润滑脂通常用作车轮轴承的润滑剂。润滑脂的物理特性，例如粘度、基础油类型和稠化剂成分，显着影响车轮轴承的整体性能和寿命。本研究调查了润滑脂的物理特性对车轮轴承摩擦扭矩和使用寿命的影响。为了评估不同润滑脂配方的效果，使用四球测试仪、流变仪和定制测试装置进行了一系列实验，以测量轴承摩擦扭矩和使用寿命。在受控操作条件下测试了具有不同粘度等级、基础油类型（矿物油、合成油）和增稠剂成分（锂、双脲和聚脲）的多种润滑脂。摩擦扭矩测量是使用高精度扭矩传感器获得的，而使用寿命是通过监测实际耐久性测试中的轴承寿命来确定的。结果表明，润滑脂的物理性能直接影响车轮轴承的摩擦扭矩和使用寿命。由于润滑膜形成增强和金属与金属接触减少，低至中粘度润滑脂通常表现出 35-40% 的低摩擦扭矩，然而，过高的粘度导致摩擦扭矩高 50-60%，从而增加能耗。不同的基础油类型表现出不同的摩擦减少和使用寿命水平，在某些情况下，矿物油表现出较低的摩擦扭矩约 30-40%，特别是在高温下，但使用寿命显着缩短。此外，增稠剂组合物显着影响润滑脂性能。基于这些发现，选择具有最佳物理性能的合适润滑脂对于最大限度地减少摩擦扭矩和延长车轮轴承的使用寿命至关重要。