| 摘要 |
A structure for closing a hole for a hydraulic circuit has, in order to prevent, for a long period of time, the leakage of oil from the hole: a flange section (22) located at the base end-side portion of a receiving groove (25), in which an O-ring (30) is mounted, and having a greater outer diameter than a shaft section (21); and a polygonal column-like head section (23) which is located at the base end-side portion of the flange section (22) and to which a fastening tool is mounted. A plug (20) is configured so that: the plate thickness (d) of the flange section (22) measured in the longitudinal direction of the shaft section (21) is less than the height (c) of the head section (23); and the outer diameter (a) of the head section (23) is less than the opening diameter (φ) of the hole (10) for a hydraulic circuit. When the plug (20) is engaged through threads with the opening end of the hole (10) for a hydraulic circuit, the plug (20) is in pressure contact with the outer surface of a body with the flange section (22) serving as the seating surface. |
