A seal cover for closing an annular opening portion having locking projections provided on an outer peripheral surface includes a fitting portion having a seal ring (example of a sealing member) fit on an outer peripheral surface and locking portions configured to be pushed and resiliently deformed by the locking projections and move over the locking projections to be locked to the locking projections when the fitting portion is fit into the opening portion. Tapered surfaces for delaying a time point when the locking portions are maximally resiliently deformed from a time point when the seal ring is maximally compressed when the fitting portion is fit and inserted into the opening portion are formed on front end parts of the locking portions in a connecting direction.

A seal cover for closing an annular opening portion having locking projections provided on an outer peripheral surface includes a fitting portion having a seal ring (example of a sealing member) fit on an outer peripheral surface and locking portions configured to be pushed and resiliently deformed by the locking projections and move over the locking projections to be locked to the locking projections when the fitting portion is fit into the opening portion. Tapered surfaces for delaying a time point when the locking portions are maximally resiliently deformed from a time point when the seal ring is maximally compressed when the fitting portion is fit and inserted into the opening portion are formed on front end parts of the locking portions in a connecting direction.

A sealing plug for sealing a hole in a plate to be sealed comprising: an operating part; a base body comprising a neck ring and a tapered ring, the neck ring comprises an annular sealing surface on an outer circumferential surface thereof, and the base body is configured to be movable towards or away from the operating part around a bottom part of the tapered ring; an upper support lip; and a lower support lip; the sealing plug is configured to seal the hole in the plate to be sealed through the annular sealing surface. The sealing plug forms a sealing structure by means of press fitting between a hole edge of the plate to be sealed and the annular sealing surface on the outer circumferential surface of the neck ring. The sealing structure of the sealing plug is irrelevant with the deformation of the upper support lip, and therefore does not affect an insertion force required to insert the sealing plug into the hole. The amount of interference between the hole edge of the plate to be sealed and the annular sealing surface of the sealing plug may be adjusted according to the requirement for a waterproof pressure.

A sufficient sealing property of a through hole is ensured. A sealing structure includes a cylindrically-shaped body part inserted into the through hole, formed of a thin plate of a first thickness, one end of the body part being open and another end of the body part being closed, a tapered part connected to the opened one end of the body part and including a diameter gradually expanding outward as a distance from the body part increases, and a first bent part connected to the tapered part, formed of a thin plate thinner than the first thickness, and bent inward so that a protruding part protruding outward elastically abuts against an inner peripheral surface of the through hole.

A hole plug attachment structure includes: a first attachment-target member is formed with a first attachment hole; a second attachment-target member is formed with a second attachment hole; and a hole plug that includes a tube-shaped outer peripheral wall, a blocking portion, a ring shaped flange jutting out toward a radial direction outer side of the outer peripheral wall from an end portion of the outer peripheral wall on an opposite side from an insertion direction so as to cover a location surrounding the second attachment hole, and a hook portion, a location of the flange that abuts an edge of the second attachment hole being thicker than a location of the flange that abuts the edge of the first attachment hole, in a state in which a back face of the flange abuts both the edge of the first attachment hole and the edge of the second attachment hole.

A hole plug attachment structure includes: a first attachment-target member is formed with a first attachment hole; a second attachment-target member is formed with a second attachment hole; and a hole plug that includes a tube-shaped outer peripheral wall, a blocking portion, a ring shaped flange jutting out toward a radial direction outer side of the outer peripheral wall from an end portion of the outer peripheral wall on an opposite side from an insertion direction so as to cover a location surrounding the second attachment hole, and a hook portion, a location of the flange that abuts an edge of the second attachment hole being thicker than a location of the flange that abuts the edge of the first attachment hole, in a state in which a back face of the flange abuts both the edge of the first attachment hole and the edge of the second attachment hole.

A hole plug includes: a tube-shaped outer peripheral wall configured to be inserted into an attachment hole formed in an attachment-target member; a blocking portion-close off the inside of the outer peripheral wall; a ring-shaped flange that juts out toward a radial direction outer side of the outer peripheral wall from an end portion of the outer peripheral wall on an opposite side from an insertion direction so as to cover a location surrounding the attachment hole; a hook portion engage with an edge of the attachment hole; and a plurality of recess portions that are formed at a front face of a base end portion of the flange at intervals around a circumferential direction of the flange, each of the recess portions including a bottom portion with a planar face profile or a curved face profile.

A hole plug includes: a tube-shaped outer peripheral wall configured to be inserted into an attachment hole formed in an attachment-target member; a blocking portion-close off the inside of the outer peripheral wall; a ring-shaped flange that juts out toward a radial direction outer side of the outer peripheral wall from an end portion of the outer peripheral wall on an opposite side from an insertion direction so as to cover a location surrounding the attachment hole; a hook portion engage with an edge of the attachment hole; and a plurality of recess portions that are formed at a front face of a base end portion of the flange at intervals around a circumferential direction of the flange, each of the recess portions including a bottom portion with a planar face profile or a curved face profile.

A hole plug includes a main body having an inner surface, a perimeter, and which further includes a center axis that is substantially perpendicular to the inner surface and defines an axial direction. Additionally, a securing member extends axially from the inner surface and includes a base directly secured to the inner surface of the main body and a cantilevered protuberance at least partially axially spaced from the inner surface. Furthermore, the protuberance at least partially extends along a circumferential path that is a parallel curve of the perimeter positioned inward from the perimeter.

A hole plug includes a main body having an inner surface, a perimeter, and which further includes a center axis that is substantially perpendicular to the inner surface and defines an axial direction. Additionally, a securing member extends axially from the inner surface and includes a base directly secured to the inner surface of the main body and a cantilevered protuberance at least partially axially spaced from the inner surface. Furthermore, the protuberance at least partially extends along a circumferential path that is a parallel curve of the perimeter positioned inward from the perimeter.