提高耐磨与破碎性的仿生凹坑形磨辊设计与试验

为了提高水泥辊压机磨辊的耐磨性与破碎性,以仿生非光滑理论为指导,在磨辊表面设计并加工出具有不同直径、不同深度、不同轴向间距及周向个数的仿生凹坑形结构,根据正交表编制试验方案并对磨辊进行磨损及破碎性试验。试验结果表明,仿生凹坑形结构可以有效提高磨辊的耐磨性与破碎性。相对于标准磨辊,其耐磨性最大提高29.06%,破碎性最大提高18.7%。当仿生磨辊的凹坑直径为8 mm、凹坑深度为2 mm、轴向凹坑间距为16 mm、周向凹坑个数为12时,是兼具耐磨性及破碎性的最优辊。通过有限元方法对磨辊所受应力进行分析时发现,合理的仿生凹坑形结构可以优化磨辊表层受力,减少磨辊磨损;磨辊挤压石英砂破碎时受到的最大挤压力是影响其破碎性的重要因素。通过单颗粒石英砂破碎试验可知,仿生凹坑形结构减少了石英砂对其表面的刻划,分散了石英砂对其表面的挤压力,提高了磨辊的耐磨性及破碎性。

Design and experiment of bionics pit shape grinding roller for improving wear resistance and crushability

Abstract: Cement is a basic material, which plays an important role in ensuring national economic construction. Cement grinding roller press plays an important role in cement production and grinding process. The grinding roller is the key component on the grinding roller press and the abrasion loss is quite large. Therefore, increasing the wear resistance and reducing abrasion loss of the grinding roller press will bring huge economic benefits to cement production. Organisms have evolved a large number of non-smooth surface structures in the process of natural selection. Such as the scale structure on the surface of the pangolin, the fringe structure on the shell surface, the blocky protuberance structure on the surface of the lizard, etc. These non-smooth structures play an important role in improving wear resistance and reducing abrasion of biological surfaces. In order to improve the wear resistance and fragmentation of cement grinding roller press. Based on the excellent wear resistance and drag reduction characteristics of the non-surface structure. Guided by bionics non-smooth theory. According to the working principle and actual size of the grinding roller press. The bionic pit shape structure with different depth, different diameter, different axial spacing and different circumferential angle designed on the surface of grinding roll. Each factor selected at two levels. The factors of the pits arranged according to the orthogonal experimental design method. The grinding roller machined according to orthogonal experimental design. To do the wear test of the grinding roller after processing carried out. The composition and structure of the test bench are basic the same as the actual roller press. Two relatively rotating grinding rollers driven by an electric motor. The grinding rollers extruded the abrasive quartz sand in the middle of them. The wear condition judged by measuring the quality loss. The test results showed that the reasonable bionic pit structure could significantly improve the wear resistance of the grinding roller. The wear resistance of the grinding roller improved by 29.06% compared with the standard grinding roller. In order to explore the wear mechanism of bionic grinding roller, the force analysis of the grinding roller analyzed by finite element software. The reasonable bionic pit shape structure could effectively reduce the stress in the inner surface and the stress distribution of grinding roller surface. It can also reduce the stress gradient and optimize the force on the grinding roller surface, reduce abrasion and improve wear resistance. The crushing test of the grinding roller carried out according to the orthogonal experimental design. The fragmentation rate of quartz sand used as a criterion for evaluating crushability. The bionic pit structure can effectively improve the crushability of the grinding roller according to the test results. Its crushability increased by 18.7% compared with the standard grinding roll. Combined with the explicit dynamic finite element method to explore the crushing process of grinding roller. It found that the maximum extrusion pressure was an important factor affecting the crushability of grinding roller. It found that the maximum extrusion pressure was an important factor affecting the crushability of grinding roller. It was the best grinding roller with both wear resistance and breakage when the diameter of the pit is 8 mm, the depth of the pit is 2 mm, the distance of the axial pit is 16 mm and the number of circumferential pit is 12. The single particle crush test of the bionic grinding roller carried out and the whole process of quartz sand breakage recorded by high-speed camera. Compared with the standard grinding roll, the bionic pit shape grinding roller can seize quartz sand quickly, form transient stability structure, reduce the sliding probability of quartz sand on the grinding roller surface. Reduced the probability of scratch on the grinding roll surface by the quartz sand. The bionic pit shape structure makes the single point support become multi-point support in the process of extruding quartz sand by grinding roller. The extrusion force dispersed which was the important reason to improve the abrasion resistance and crushability of the grinding roller press.