自动脱螺纹注塑模液压马达脱螺纹与推板推出动作关系的工程分析

Engineering Analysis for Relations between Actions of Hydraulic Motor Unscrewing and Ejector Plate Ejecting in Automatic Unscrewing Injection Mould

针对自动脱螺纹注塑模具中液压马达脱螺纹速度与弹簧驱动的推板推出速度可能存在不同步的问题,对液压马达脱螺纹动作规律进行了论述,对弹簧驱动的推板推出动作规律进行了运动学分析,通过对这两种动作规律的比较得出了一个结论,即在实际工程应用中选用的液压马达多为低速马达的情况下,液压马达轴向脱螺纹速度总是制约弹簧驱动的推板推出速度,从而实现了一种制约同步。根据这个结论,为避免出现塑件螺纹损坏的情况,在模具结构允许的情况下,应尽量选择劲度系数较低的推板弹簧。

Aiming at the problems of that the hydraulic motor unscrewing speed may not match the ejecting speed of the spring-driven ejector plate in automatic unscrewing injection mould, thus the rules of the hydraulic motor unscrewing actions were discussed, and the rules of the spring-driven ejector plate ejecting actions were also analyzed through kinematics. Through the comparison of these two kinds of rules, it comes to the conclusion that under the conditions that the low speed hydraulic motor type is mainly selected in the practical engineering application, the axial unscrewing speed of the hydraulic motor always restricts the ejecting speed of the spring-driven ejector plate, so they realize restricting synchronization. According to the conclusion, in order to avoid damage to the plastic parts thread, under the mould structure allowing conditions, low stiffness coefficient springs should be chosen in the mould for the ejector plate.