冠型气压砂轮的接触应力分析

Contact stress analysis of new crown-type pneumatic wheel

摘要:

为解决半球型气压砂轮光整加工过程中接触应力分布不均匀问题，设计一种新型的冠型气压砂轮，对气压砂轮动态接触过程中柔性变形进行分析，建立砂轮旋转变化下的应力应变关系式；对冠型与半球型气压砂轮的接触应力进行仿真对比分析，研究压缩量对不同尺寸结构冠型气压砂轮应力分布的影响，仿真结果表明：冠型气压砂轮与工件接触区域应力分布近似呈圆形，且数值均匀呈高斯型分布，有效克服了半球型气压砂轮接触中心区域应力缺陷的现象. 激光强化Cr12模具的光整加工试验结果表明：D=40、80和120 mm的冠型气压砂轮，最佳压缩量分别为3、4和5 mm，平均表面粗糙度分别能达到150～160、60～65和30～33 nm. 冠型气压砂轮有效地提高了光整效率与面形精度，可以针对不同加工对象，优选最佳光整工具.

Abstract:

To solve the problem of uneven distribution characteristic of contact stress with dome pneumatic wheel finishing for large laser hardening mold, a new crown-type pneumatic wheel is designed, and the stress-strain relationship is obtained by the analysis of flexible reformation during the dynamic contact process. By comparing the different stress distribution of dome and crown-type models via finite element analysis and the effect of different compression to different sizes of crown-type models, it comes to the conclusion that the contact area of the crown-type pneumatic wheel is an approximate circular and the stress value performances Gaussian type distribution, which effectively overcomes the contact stress defects of central region with dome pneumatic wheel. The pneumatic wheel finishing experiment with the laser hardening Cr12 mold shows that the optimum amount of compression is 3, 4 and 5mm with diameter 40, 80 and 120mm respectively, and the average surface roughness is 150~160, 65~60 and 30~33 nm. The crown-type pneumatic wheel can effectively improve the finishing efficiency and surface accuracy, and different sizes fit different processing objects.