微凹坑织构表面对脂润滑关节轴承摩擦特性的影响

为研究脂润滑下表面织构对关节轴承摩擦特性的影响,设计和制造了4组表面高度算术平均值相同、表面微凹坑面积占有率分别为7%、10%、15%和21%的关节轴承内圈表面形貌.使用Talysurf CCI Lite非接触式三维轮廓仪对试件表面进行测量,采用ISO25178定义的表面参数对试件表面形貌进行表征.在改造的HDM-20端面摩擦磨损试验机上,采用2#锂基脂润滑在不同载荷、转速条件下进行了一系列摩擦磨损试验,研究了表面形貌参数与摩擦系数的关系.在本试验中,选取表面高度算术平均值Sa和表面峰态Sku等表面高度参数、表面峰区平均材料体积Vmp、表面中心区平均空体体积Vvc和表面谷区平均空体体积Vvv等表面功能参数以及平均谷体积Sdv等表面特征参数对关节轴承表面形貌进行表征.结果表明:各表面参数对摩擦系数的影响不同,将表面高度参数、功能参数和特征参数这几种表面形貌参数结合对关节轴承表面形貌进行表征,更有利于脂润滑下关节轴承表面形貌的摩擦学设计.

Influence of Micro-cavity Textured Surface on Tribological Property of Grease Lubricated Spherical Bearing

In order to study the influence of surface texture on tribological properties of grease lubricated spherical bearing, four kinds of specimens were designed and manufactured which have the same surface arithmetic average height and their area densities of micro-cavity were 7%, 10%, 15% and 21% respectively. The surfaces of specimens were measured by Talysurf CCI Lite 3D non-contact surface profiler and characterized with surface parameters defined in ISO25178. With the lubrication of lithium grease, a series of frictional experiments under operating conditions of different loads and velocities were conducted on a modified HDM-20 end-face tribo-tester. The correlations between surface parameters and friction coefficient were studied. Height parameters of arithmetical mean height and kurtosis, functional parameters of material volume in peak zone, void volume in core zone and void volume in valley zone of surface, feature parameter of mean dale volume were chosen to characterize surface topography. The results show that these surface parameters had different effects on friction factor. It is beneficial for the tribological design of surface topography of grease lubricated spherical bearing to characterize surface by the combination of height parameters, functional parameters and feature parameter.