| 摘要 |
Provided is a reciprocating sealing device shaped so that volume absorbing performance is improved, preventing full-surface contact of the packing from readily occurring even when there is an increase in internal pressure, and thereby making it possible to obtain an excellent sealing performance. In order to achieve this purpose, this invention is a sealing device in which a packing is mounted on a mounting groove provided to one of two members that perform a reciprocating motion relative to each other and the packing is brought into intimate contact with the other member to obtain a seal between the two members, the packing being provided with an annular base part, a stationary-side lip, and a sliding-side lip, and a pack ring having a lower hardness than that of the packing being interposed between the annular base part and the groove side surface of the mounting groove. A pack ring forms a space region between the pack ring and the other member. The annular base part is shaped so that the heel part has an arc-shaped or tapered cross-section and the annular base part does not protrude beyond an extension line of a peripheral surface of the sliding-side lip in a free state. The edge surface of the annular base part is provided with a flat part within the range at which contact is made with the pack ring. |
