精密难加工孔挤压液膜阻尼理论与技术研究

The precision holes are usually important or key units of machinery and generally produced by fine boring, fine grinding, honing and lapping. Because of boring and grinding working in cantilever condition, so toughness of cutter bar or grinding wheel spindle is low. It lead to dimensional accuracy, form and location tolerance accuracy of holes are low, surface roughness of holes and machining quality are not high. By analysis of forces and motions in grinding wheel spindle and cutter bar, the cause of squeeze fluid film formation was expatiated. It was analyzed that the excentricity of fluid film journal effect on squeeze fluid film pressure, stiffness coefficients and damping coefficients. It was studied that the steady-state performance and the translent performance of the fluid film damping machining system. A kinetic model of grinding wheel spindle and cutter bar with squeeze fluid film dampers was established. It was simulated that the damper radial clearance, damper length, kinetic viscosity and radius of damper effect on the center trace of grinding wheel spindle and cutter bar. The result of simulations shows that small damper radial clearance, long damper length, sticky fluid and large radius are benefit to reduce the area forming by the center trace of grinding wheel spindle or cutter bar. The result of experiments shows the amplitude of grinding wheel spindle or cutter bar was attenuated by 40%. Base on the theoretical and experimental research works, the preferential damping parameters were given. In order to examine the reliability of preferential damping parameters, a grinding wheel spindle with squeeze fluid film dampers for precision holes was designed with the provided preferential damping parameters and the field testes were done. The result of testes shows that the preferential damping parameters are reliability.

精密孔加工首次采用挤压液膜阻尼技术，形成液膜阻尼效应，显著提高加工质量和效率，为精密难加工孔探索一条可靠有效的新途径。研究加工系统挤压液膜阻尼机理、成因条件及相关参数影响规律等理论体系；提供阻尼工况参数、仿真模型及阻尼装置等，指导现场加工。结合科学前沿和制造业重要科技问题，具有较高科学水平、重要研究意义和广泛应用前景。.