仿生通孔形活塞裙部耐磨性能研究

目的为了减少发动机活塞裙部磨损,提高裙部耐磨性。方法基于仿生非光滑理论,以蚯蚓体表形态为仿生原形,在LX-2V型发动机活塞裙部设计出以孔的直径、每行孔间距、孔沿圆周角度为参数的仿生通孔形结构。采用正交设计方案对不同参数的仿生通孔形活塞进行有限元热结构耦合分析。以裙部最大变形量、裙部变形范围、裙部对称中心线上点与一侧点的应力差值作为评价活塞裙部耐磨性的标准,优选出模拟分析中耐磨性能良好的三个仿生活塞,并与标准活塞同时进行发动机台架磨损试验。结果合理的仿生通孔形结构可以有效减少活塞裙部磨损,提高裙部耐磨性。相对于标准活塞,当仿生活塞孔的直径为5 mm、每行孔的间距为6.5 mm、孔沿圆周角度为16°时,其耐磨性最大提高49%。结论过小的裙部最大变形量、过大的裙部变形范围,均不利于活塞裙部与缸套之间油膜的形成与保持,从而使活塞裙部磨损加剧。结合活塞裙部粗糙度值分析可知,合理的仿生通孔形结构可以优化裙部表面所受摩擦力,是进一步降低活塞裙部所受磨损的重要原因。

Wear Resistance of Piston Skirt with Bionic Through Hole

The paper aims to reduce wear of piston skirt and improve its wear resistance. The surface morphology of earthworm was taken as the bionic prototype based on the bionic non-smooth theory. A bionic through-hole structure with diameter of the hole, the distance between the holes per row and the angle of the hole along the circumference as parameters was designed in the piston skirt of LX-2V engine. Orthogonal design was applied to analyze the bionic piston with different parameters through finite element thermal structural coupling method. The maximum deformation amount of skirt, the deformation range of skirt, the stress difference between the symmetrical center line and the side point of skirt were taken as the wear resistant evaluation standards of piston skirt. Three bionic pistons and standard pistons with good wear resistance were selected through imitating method to carry outwear test of engine bench. The test results showed that the bionic through hole of reasonable structure can effectively reduce wear of the piston skirt and improve its wear resistance. Compared with the standard piston, the wear resistance of the bionic piston hole was improved by 49% when the diameter of the bionic piston hole was 5 mm, the spacing of each row hole was 6.5 mm, and the hole was 16° along the circumference angle. The maximum deformation of the skirt is too small and the deformation range of the skirt is too large. Both are not conducive to formation and maintenance of the oil film between the piston skirt and the cylinder liner, which will aggravate the wear of the skirt. Based on roughness value analysis of the piston skirt, reasonable bionic through-hole structure can optimize the surface friction of skirt. It is an important reason to further reduce the wear of piston skirt.