| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that when a rear end of a screw of an injection unit is sealed by a cornice, a structure is complicated, and hence a simpler sealing structure is required. SOLUTION: A first intermediate cylinder 41 is engaged with a cylindrical part 36 of a rotary cylinder 35, a second intermediate cylinder 42 having a slightly larger diameter is engaged with the cylinder 41 via a second seal ring 43, a third intermediate cylinder 44 having a slightly larger diameter is engaged with the cylinder 42 via a third seal ring 45, a fixed cylinder 45 having a slightly larger diameter is engaged with the cylinder 44 via a fourth seal ring 47, and the cylinder 46 is fixed to a bearing base 12. That is, the seal structure 30 has the above-mentioned cylinder 35, the first to third cylinders 41, 42 and 44, the cylinder 46 and first to fourth seal rings 38, 43, 45 and 47. The sealing structure is formed in a telescopic expansion cylinder. As a result, a guide member such as a guide rod or the like can be unneeded, and hence the sealing structure can be simplified. COPYRIGHT: (C)2003,JPO
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