| 摘要 |
<p>A HOLLOW BODY FORMED OF A THERMOPLASTIC RESIN AND HAVING UNIFORM INNER DIAMETER AND THICKNESS AND AN EXCELLENT INNER SURFACE SMOOTHNESS, AND, IN PARTICULAR, A PIPE-SHAPED HOLLOW BODY HAVING A BENT PORTION IS MANUFACTURED BY INJECTION MOLDING. A METHOD OF MANUFACTURING A HOLLOW BODY INCLUDES INJECTING A MOLTEN RESIN 8 INTO A MOLD CAVITY 2 OF A MOLD 1, THE MOLD CAVITY 2 HAVING ON ITS ONE END A PRESSURE PORT 4 PROVIDED WITH A FLOATING CORE 6 AND ON ITS OTHER END AN OUTLET 5, PRESSURE-INJECTING A PRESSURIZED FLUID THROUGH THE PRESSURE PORT 4 AFTER THE INJECTION OF THE MOLTEN RESIN 8, AND MOVING THE FLOATING CORE 6 TOWARD THE OUTLET 5, AND, AT THE SAME TIME, EXTRUDING THE MOLTEN RESIN 8 FROM THE OUTLET 5. IN THE METHOD, THE FLOATING CORE 6 IS CONSTITUTED OF A COLUMNAR PORTION AND A TOP PORTION, WHICH IS CONTINUOUSLY CONNECTED TO ONE SURFACE OF THE COLUMNAR PORTION AND HAS A SHAPE THAT A CROSS-SECTIONAL AREA PERPENDICULAR TO A CENTRAL AXIS OF THE COLUMNAR PORTION GRADUALLY DECREASES FROM ONE SURFACE SIDE OF THE COLUMNAR PORTION. WHEN A DIAMETER OF THE COLUMNAR PORTION IS REPRESENTED BY A, THE HEIGHT OF THE COLUMNAR PORTION IS 0.1 A TO 1 A, AND THE HEIGHT OF THE TOP PORTION IS 0.3 A TO 1.6 A. (FIGURE 1)</p> |
