Abstract:

Aimed at the requirement for the automatic injection molding production of complex plastic parts for a scroll compressor air valve，a type of three-plate mold with two cavities was designed. In this mold， according to the structural characteristics of four local features of the plastic parts， four kinds of demolding mechanisms were optimized to implement automatic demolding， which included a four-time demolding composite mechanism， a two-time demolding composite mechanism， an inclined guide pillar slider mechanism and a fixed mold bending pin core pulling mechanism. In the four-time demolding composite mechanism， the first core demolding of central inner hole was completed by using an external cylinder mechanism， then the second and third core demolding of mouth and end face were completed by using a delay slider mechanism， and finally the forth rotation core demolding of internal thread was completed by using the cylinder rack mechanism. In the second demolding composite mechanism， the first core demolding of central inner hole was completed by the inclined guide pillar slider mechanism， and the second core demolding of internal thread was completed by a cylinder rack mechanism. A universal mechanism was adopted to design the slider mechanism and fixed mold bent pin core pulling mechanism. Through the optimization design of the cylinder rack driving mechanisms in the four-time and two-time compound mechanisms， the overall structure size of the mold was optimized， and the operation cost of injection-molding machine was reduced effectively.

Key words: scroll compressor, air valve, injection molding, mold structure, mechanism design, optimization