【作者】 卢磊；

【导师】 王家序；

【作者基本信息】 重庆大学 ， 机械设计及理论， 2010， 硕士

【摘要】 对于水润滑橡胶合金轴承,低粘度的润滑介质和橡胶衬层特殊的材料性质,使得其润滑机理较一般油润滑金属滑动轴承产生了很大的差异。多沟槽的几何结构,加上水的粘性小,水润滑橡胶合金轴承中水膜的压力普遍较低。但由于橡胶材料的弹性模量较小,在较低的水膜压力下会产生明显的变形,从而对润滑水膜的厚度和形状将产生显著的影响,并进一步影响水膜中的压力分布。因此,对水润滑橡胶合金轴承润滑机理的研究上,既要考虑多曲面、多沟槽的几何结构,也要充分考虑衬层材料性能对润滑性能的影响。为了了解水润滑橡胶合金轴承在重载、干摩擦状态下的润滑特性,论文利用有限元方法对不同载荷、不同摩擦系数条件下的水润滑橡胶合金轴承进行了动态接触分析。计算的结果表明,由于摩擦力的存在,最大接触应力、最大接触位移和最大接触应变一般出现在轴承两端或底部板块沿旋转方向下游的区域。之后,采用直接流固耦合求解方法从全周向尺度对水润滑橡胶合金轴承进行了润滑性能分析。首先从水润滑橡胶合金轴承的特殊性出发,结合Navier-Stokes方程和弹性变形等理论,建立了水润滑橡胶合金轴承的润滑求解模型,对不同偏心率、不同转速下的水润滑橡胶合金轴承进行了数值仿真,得到了不同状态下的水膜压力分布、橡胶变形分布规律,并在此基础上计算了相应的水膜厚度分布、承载能力和摩擦系数。接着,从过渡圆弧尺寸、橡胶衬层厚度和衬层材料性能几个方面出发,研究了不同因素对水润滑橡胶合金轴承润滑性能的影响。流固耦合的求解结果表明,在偏心率小于等于1的情况下,水润滑橡胶合金轴承的承载能力普遍较低(计算范围内的最大比压约为0.08MPa);采用较小的过渡圆弧尺寸会增加收敛楔形的长度,从而有利于承载能力的提高;在偏心率较大的情况下,较小的衬层厚度有助于水膜压力的提高,其承载能力也相应增大;在轴承刚性间隙相同的条件下,衬层材料弹性模量越低,对应的水膜厚度越厚,但承载能力也会相应降低。本文内容是国家自然科学基金面上项目“大尺寸高比压水润滑轴承的创新设计理论与方法”(项目编号:50775230)的一部分,拟通过上述研究对水润滑轴承的润滑机理及相关研究方法提供新的借鉴。更多还原

【Abstract】 Owing to the low viscosity of water and special material properties of rubber bushing, the water lubricated rubber alloy bearings have performances different from those of traditional oil lubricated metal bearings in the lubrication mechanism. For the water lubricated rubber alloy bearings with multi-groove structure, the lower film pressure can occur. Meanwhile, owing to the low elasticity of rubber materials, serious deformation can appear on the bushing of the bearings, even on the relatively lower film pressure, thus changing the water film thickness and its shape, and further affecting the film pressure distribution. Therefore, in the case of the lubrication mechanism of water lubricated rubber alloy bearings, what should be considered not only including their structure like multi-surface and multi-groove ones, but also including their material properties of rubber bushing.A finite element method (FEM) was employed in order to gain an insight into the lubrication characteristics of a water lubricated rubber alloy bearing under the conditions of heavy load and dry friction, where dynamic contact analysis of the bearing was carried out with different loads and different friction coefficients. The study shows that the maximum contact stress, maximum contact displacement and the maximum strain usually exist at both ends in bearing length direction or the downstream along the rotation direction of the bearing.The lubrication performance of the water lubricated rubber alloy bearings were analyzed at a full circumferential scale using fluid-structure interaction technique. A governing equation suitable for this kind of bearings is first established based on Navier-Stokes equation and associated elastic theories, combining the particularity of the water lubricated rubber alloy bearings with a fluid-structure interaction technique. The film pressure and the deformation distributions of the rubber bushing are separately investigated on the condition of different eccentricities and different speeds using numerical simulation method, further the corresponding water film thickness distribution, load-carrying capacity and friction coefficient achieved. Afterward, influences of some factors, including the radius of corner, the thickness of rubber and material properties of bushing, on lubrication performances of the bearings are studied.The numerical results reveal that the load-carrying capacity of a water lubricated rubber alloy bearing is lower in the case of eccentricity ratio less than and equal to unit (the maximum pressure of 0.08Mpa can be found in the present study). It is also found that a decreasing radius of corner for the bearing increases the convergent wedge length, which is helpful to the improvement of load-carrying capacity, while in the case of large eccentricity ratio, the film pressure for the bearing will decrease with increasing rubber bushing thickness. In the same rigid clearance, the lower elasticity modulus of bushing material, the thicker water film, but the smaller load-carrying capacity.This research is funded by the State Natural Sciences Foundation General Projects:“Innovative design theory and method of water lubricated bearing system with large size and high specific pressure”(Number:50775230). The paper will provide a reference for the study of lubrication mechanism and research methods.更多还原