Valve needle sealing assembly and hot runner system

Abstract

The invention relates to the technical field of hot runners, and discloses a valve needle sealing assembly and a hot runner system. The valve needle sealing assembly includes a sprue sleeve, a hot nozzle, a valve needle and a guide block. There is a gate on the sprue sleeve; the hot nozzle is set on the sprue sleeve, and the hot nozzle is connected to the gate; the valve needle can move along its own axis direction and is installed in the hot nozzle, and the end of the valve needle that passes through the hot nozzle A sealing head in the shape of an inverted truncated cone is provided, and the angle α between the busbar of the sealing head and the axis of the sealing head is 1-6 degrees, and the side wall of the sealing head can be attached to the inner wall of the gate , for blocking the gate; the guide block is arranged in the hot nozzle, and the valve needle passes through the guide block, and the guide block is used to limit the movement of the valve needle along its own axis. Compared with the existing straight body sealing and inclined surface sealing structures, the valve needle sealing assembly of the present invention reduces the manufacturing difficulty, improves the service life, and solves the problems of gate flash and gate protrusion.

Description

technical field [0001] The invention relates to the technical field of hot runners, in particular to a valve needle sealing assembly and a hot runner system. Background technique [0002] The existing valve pin type hot runner system mainly includes two types of sealing methods for sprue sleeves: straight sealing and inclined surface sealing. Wherein, the gap between the straight body sealant, that is, the cylindrical sealant head of the valve needle and the sealant hole of the sprue sleeve is small enough to allow the plastic to solidify at a certain temperature to seal the sealant. Inclined surface sealing means that the sealing head of the valve needle is an inverted circular table body, and the sealing hole of the sprue sleeve is a circular table hole. The sealing principle is that the side wall of the sealing head of the valve needle and the inner wall of the gate of the sprue sleeve interact Press to seal. [0003] However, there are different problems in the two sea...

AI Technical Summary

Problems solved by technology

The sealing head of the existing inclined valve needle 400 is in the shape of an inverted circular platform. The angle α between the busbar and the axis of the sealing head of the inclined valve needle 400 is relatively large, and the standard angle is 20 degrees. The large angle α is due to the If the angle α is too small, it will not be able to compensate for the yaw error of the inclined valve needle 400 when it is closed, which will cause the sealing head of the inclined valve needle 400 to touch the gate of the inclined gate sleeve 500 when closing the gate of the inclined gate sleeve 500. damage to the inner wall of the mouth

However, when the slope valve needle 400 closes the slope sprue sleeve 500, relying on the contact pressure S of the sealing head of the slope valve needle 400 to the inner wall of the gate of the slope sprue sleeve 500 to extrude plastic, if the contact pressure S is insufficient, the plastic cannot be processed. If it is completely extruded, there will be a problem of gate flash

However, the angle α between the busbar and the axis of the sealing head of the existing slope valve needle 400 is relatively large. In order to completely seal the gate of the slope sprue bushing 500, under the condition that the required contact pressure S is constant, The larger the included angle α, the greater the sealing force F required, which will cause the gate of the inclined sprue sleeve 500 to protrude due to the excessive sealing force F received (gate protruding That is, under the extrusion of the sealing force F along the axial direction, the gate of the inclined sprue bushing 500 protrudes along the axial direction)

Therefore, the existing bevel sealant has the problems of gate flash and gate protrusion

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