| 摘要 |
A valve pin bushing for a valve gated injection molding apparatus having, a back plate, a valve pin bushing, and a manifold, with axially aligned respective valve pin bores. The valve pin bushing includes a back plate contacting surface and an opposite manifold contacting surface for bearing against the back plate and manifold, respectively. The back plate contacting surface has a surface area larger than a surface area of the manifold contacting surface to draw heat from the valve pin bushing to the cooler back plate. An air gap, which may be sealed by an optional sealing portion, is formed where the flange is spaced away from a central portion of the valve pin bushing near the manifold. The valve pin bushing also includes a tubular member for positioning within the manifold valve pin bore, which defines a portion of the manifold melt passageway.
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