| 摘要 |
The invention relates to a needle valve nozzle (10) for an injection mould, comprising a nozzle body (20) that contains at least one melt channel (30), the latter terminating against or in a nozzle mouthpiece (40) and having a fluidic connection to a mould cavity of the injection mould that is formed by at least one mould insert (50). A shut-off needle (60) penetrates the melt channel (30) and the nozzle mouthpiece (40) and can be displaced longitudinally through said parts, moving from an open position into a closed position. At least one infeed cone (46) is provided upstream of a seal seat (D), in order to centre the shut-off needle (60), the lower end of which forms a shut-off part (70). The aim of the invention is to guarantee a constantly precise guidance and sealing of the needle, whilst at the same time preventing an impairment of the temperature distribution in the vicinity of the nozzle tip. To achieve this, the nozzle mouthpiece (40) consists of a material with high thermal conductivity, whilst the or each infeed cone (46) for the shut-off needle (60) is configured in a centring body (80) consisting of wear-resistant material and running concentrically with the longitudinal axis (L) of the needle valve nozzle (10). The centring body is held against and/or in the nozzle mouthpiece (40) in a positive-fit and its end section (84), which forms an outlet opening (44) for the melt, can be engaged with the mould insert (50).
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