Minor-caliber thick-wall heat shrinkable pipe expansion mold and expansion system thereof

Abstract

The invention discloses a minor-caliber thick-wall heat shrinkable pipe positive pressure expansion mold and an expansion system thereof. The expansion mold comprises a mold butt joint flange, an exhaust pipe core, an expansion pipe core and a sizing pipe core which are sequentially and fixedly communicated, wherein an exhaust pipe core outer sleeve is arranged outside the exhaust pipe core in a sleeving way; an exhaust through hole used for exhausting is formed in the exhaust pipe core outer sleeve; an expansion pipe core outer sleeve is arranged outside the expansion pipe core in a sleevingway; an inflation hole is formed in the expansion pipe core outer sleeve; a pressure maintaining cavity is defined between the expansion pipe core outer sleeve and the expansion pipe core; a pluralityof small exhaust holes are formed in a position, surrounded by the exhaust pipe core outer sleeve, of the exhaust pipe core; and a plurality of small pressure maintaining holes are formed in a position, surrounded by the expansion pipe core outer sleeve, of the expansion pipe core. The minor-caliber thick-wall heat shrinkable pipe positive pressure expansion mold and the expansion system have theadvantages that the contact friction on the pipe inner walls of the heat shrinkable pipe and the expansion pipe core is reduced, or even avoided, so that the heat shrinkable pipe can maintain the performance of lower eccentricity, stable longitudinal shrinkage rate and smoothness.

Description

【Technical field】 [0001] The invention relates to the technical field of mechanical manufacturing, in particular to an expansion die for a small-diameter thick-walled heat-shrinkable tube and an expansion system thereof. 【Background technique】 [0002] At present, the heat-shrinkable tube expansion system includes a conveying device, a heating furnace, an expansion device, a cooling device and a traction device. The small-diameter heat-shrinkable tube expansion device generally adopts a negative pressure method, that is, a vacuum is drawn in the expansion mold to cause a negative pressure, so that the Heat-shrinkable tube expansion; in negative pressure expansion, the expansion mold is usually set with a slight air leak to properly reduce the vacuum degree to prevent the problem of excessive longitudinal shrinkage of the heat-shrinkable tube caused by the tight fit between the heat-shrinkable tube and the inner wall of the expansion mold . However, for thick-walled heat-shr...

AI Technical Summary

Problems solved by technology

However, for thick-walled heat-shrinkable tubes with small diameters and high magnifications, the partial vacuum degree caused by negative pressure expansion due to air leakage will cause severe wall deviation of the expanded product. low level

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