Yu Liang, Zheng Changsong, Wang Liyong, Wu Jianpeng, Jia Ran
Ministry of Education Key Laboratory of Modern Measurement and Control Technology, Beijing Information Science and Technology University, Beijing 100192, China.
School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Materials (Basel). 2022 Nov 3;15(21):7758. doi: 10.3390/ma15217758.
The relationship between clutch thermodynamic characteristics and contact states of friction components is explored numerically and experimentally. The clutch thermodynamic numerical model is developed with consideration of the contact state and oil film between friction pairs. The clutch bench test is conducted to verify the variation of the clutch thermodynamic characteristics from the uniform contact (UCS) to the intermittent contact (ICS). The results show that the oil film decreases gradually with increasing temperature; the lubrication state finally changes from hydrodynamic lubrication to dry friction, where the friction coefficient shows an increasing trend before a decrease. Thus, the friction torque in UCS gradually increases after the applied pressure stabilizes. When the contact state changes to ICS, the contact pressure increases suddenly and the oil film decreases rapidly in the local contact area, bringing about a sharp increase in friction torque; subsequently, the circumferential and radial temperature differences of friction components expand dramatically. However, if the contact zone is already in the dry friction state, friction torque declines directly, resulting in clutch failure. The conclusions can potentially be used for online monitoring and fault diagnosis of the clutch.
通过数值模拟和实验研究了离合器热力学特性与摩擦副接触状态之间的关系。考虑摩擦副之间的接触状态和油膜，建立了离合器热力学数值模型。进行了离合器台架试验，以验证离合器热力学特性从均匀接触（UCS）到间歇接触（ICS）的变化。结果表明，油膜随着温度升高而逐渐减小；润滑状态最终从流体动力润滑转变为干摩擦，在此过程中摩擦系数先呈上升趋势后下降。因此，在施加压力稳定后，UCS中的摩擦扭矩逐渐增加。当接触状态变为ICS时，接触压力突然增大，局部接触区域的油膜迅速减小，导致摩擦扭矩急剧增加；随后，摩擦副的周向和径向温差急剧扩大。然而，如果接触区域已经处于干摩擦状态，摩擦扭矩将直接下降，导致离合器失效。这些结论可潜在地用于离合器的在线监测和故障诊断。
