Joint Clearances With Lubricated Long Bearings in Multibody Mechanical Systems
Joint Clearances With Lubricated Long Bearings in Multibody Mechanical Systems
复制标题
DOI：
10.1115/1.1314867
复制
发表时间：
2000-12
影响因子：
3.3
通讯作者：
P. Ravn;S. Shivaswamy;B. Alshaer;H. Lankarani
中科院分区：
文献类型：
--
作者：
P. Ravn;S. Shivaswamy;B. Alshaer;H. Lankarani
在多体机械系统的分析和设计中，关节间隙的正确建模是非常重要的。间隙可能是由于制造过程中的磨损或缺陷造成的。当间隙中没有润滑剂时，发生固体与固体的接触。由于链路之间的接触而产生的脉冲在整个系统中传输。润滑剂的存在避免了这种接触，因为由润滑剂膜产生的流体动力支撑作用在物体上的载荷并防止物体接触。本文对有润滑和无润滑的多体机械系统转动副间隙进行了分析。挤压以及粘性效应被认为是利用流体动力润滑理论在长轴承。与传统的机械设计方法不同，瞬时润滑力是未知的，并根据已知的轴颈和轴承的几何位置和速度进行评估。在分析没有润滑剂的接头间隙的情况下，使用修改的赫兹关系来模拟轴颈和轴承之间的冲击或接触，其包括滞后阻尼项以考虑冲击期间的能量耗散。该方法适用于分析的曲柄滑块机构有间隙的活塞销。仿真进行了有和没有润滑剂和结果进行了比较，它表明，润滑剂的结果在一个稳定的运动，在所需的曲柄力矩为系统的峰值较少。
Proper modeling of joint clearance is of great importance in the analysis and design of multibody mechanical systems. The clearance may be due to wear or imperfection in manufacturing. When there is no lubricant in the clearance solid-to-solid contact occurs. The impulse due to contact between the links is transmitted throughout the system. The presence of a lubricant avoids such contact, as the hydrodynamic forces developed by the lubricant film support the loads acting on the bodies and prevent the bodies from coming into contact. In this paper, an analysis of revolute joint clearances in multibody mechanical systems with and without lubricant is presented. Squeeze as well as viscous effects are considered utilizing the hydrodynamic theory of lubrication in long bearings. Unlike the traditional machine design approach, the instantaneous lubricant forces are the unknown and evaluated in terms of the known geometrical position and velocity of the journal and bearing. In the case of analysis of a joint clearance with no lubricant, a modified Hertzian relation is used to model the impact or contact between the journal and bearing, which includes a hysteresis damping term to account for the energy dissipation during impact. The methodology is applied for the analysis of a slider-crank mechanism having a clearance in the piston pin. The simulations are carried out with and without lubricant and the results are compared, It is shown that the lubricant results in a steady motion with fewer peaks in the required cranking moment for the system.