Valve needle guiding sleeve assembly and hot channel system therewith

Abstract

The invention discloses a valve needle guiding sleeve assembly. The valve needle guiding sleeve assembly comprises a valve needle and a guiding sleeve, wherein the guiding sleeve includes a lengthwaysthrough hole and an inner wall, and the through hole is defined by the inner wall; the valve needle is movably penetrates through the through hole in the longitudinal direction; the guiding sleeve isalso includes a flashing groove which is concavely formed in the inner wall; the flashing groove encircles the through hole and is in a closing ring structure; and the flashing groove includes an opening end which communicates with the through hole and a closing end is relatively away from the through hole. According to the valve needle guiding sleeve assembly, the flashing groove is concavely formed in the inner wall of the through of the guiding sleeve, the molten plastic cement can be stored in the flashing groove, and a plastic cement sealing layer can be formed after the cooling and curing of the plastic cement, so that the requirement of fitting accuracy between the valve needle and the guiding sleeve an be reduced, the problem of plastic cement leaking in the fitting clearance between the valve needle and the guiding sleeve can be solved, the tightness of the fitting clearance can be enhanced, and meanwhile the risk of the valve needle seized by the thermal expansion is reduced.

Description

technical field [0001] The invention relates to the technical field of hot runners, in particular to a valve needle guide sleeve assembly and a hot runner system with the valve needle guide sleeve assembly. Background technique [0002] Guide sleeves are widely used in hot runners. [0003] The guide sleeve and the valve needle are precisely matched, and the matching gap is between 0.003 and 0.009mm. If the precision is not enough, the fit gap will be large, and the molten plastic will overflow from the gap between the guide sleeve and the valve needle, resulting in glue leakage in the hot runner system. If it is serious, the production must be stopped to deal with the abnormality. The hot runner system needs to operate under high temperature conditions, and the device will generate a certain amount of thermal expansion. If the matching gap between the guide sleeve and the valve needle is too small, the up and down movement of the valve needle will be affected, and the valv...

AI Technical Summary

Problems solved by technology

If the precision is not enough, the fit gap will be large, and the molten plastic will overflow from the gap between the guide sleeve and the valve needle, resulting in glue leakage in the hot runner system. If it is serious, the production must be stopped to deal with the abnormality.

The hot runner system needs to operate under high temperature conditions, and the device will generate a certain thermal expansion. If the gap between the guide sleeve and the valve needle is too small, the up and down movement of the valve needle will be affected, and the valve needle may be stuck.

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