液性塑料定心夹具的结构优化设计

Structure optimization design of hydraulic plastic centering clamp

对液性塑料定心夹具进行有限元建模和分析,发现了传统设计中的一些误区,得出工件长度、液体摩擦和套筒材料是影响夹具精度的主要因素。提出将套筒内部长度分为两段的优化设计,由自锁"阀门"控制,调节保持"阀门"两侧始终压力相等,避免了因套筒过长造成的液体摩擦压力损失。优化后,在不增加外压力和材料强度许可下,使套筒平均工作应力达到460.18MPa,提高了套筒的夹紧力,套筒薄壁位移由4.46μm增加到5.20μm,定位精度达到了IT5～IT6。为精加工提供了保障。

Major factors of influencing accuracy of clamp,such as work piece length,liquid friction and sleeve material,are obtained through Finite Element Analysis of hydraulic plastic centering clamp in which some misunderstanding are found in traditional design.Then an optimal design for dividing the internal sleeve into two parts is proposed,which process shall be controlled by a self-lock＂valve＂and adjusted to maintain even pressure of two sides in order to avoid losing of liquid friction pressure occurred by overlong sleeves.After optimization the average working stress could reach to 460.18MPa without increasing external pressure,increasing material strength.Thus,clamping force of the sleeve is increased with the displacement of sleeve being increased from 4.46μm to 5.20μm and position accuracy reaching IT5 to IT6 which shall guarantee the fine processing.