Abstract: The present invention is directed to an opening structure of a fuel tank having a fuel tank wall made of plastic layers including at least an outer layer, an inner layer and an intermediate layer, with an opening portion formed to be integral with the fuel tank wall. The opening structure includes a cylindrical portion extended from the fuel tank wall outward thereof to form the opening portion, an overlapping portion extended from an end of the cylindrical portion to enlarge the diameter of the opening portion and bent at a bent portion to form an outer surface parallel with an opening end surface of the opening portion, and a compressed portion with at least a portion of the overlapping portion compressed in a direction perpendicular to the opening end surface of the opening portion.

Abstract: The present invention is directed to an opening structure of a fuel tank having a fuel tank wall made of plastic layers including at least an outer layer, an inner layer and an intermediate layer, with an opening portion formed to be integral with the fuel tank wall. The opening structure includes a cylindrical portion extended from the fuel tank wall outward thereof to form the opening portion, an overlapping portion extended from an end of the cylindrical portion to enlarge the diameter of the opening portion and bent at a bent portion to form an outer surface parallel with an opening end surface of the opening portion, and a compressed portion with at least a portion of the overlapping portion compressed in a direction perpendicular to the opening end surface of the opening portion.

Abstract: A lower wall partially defining a fuel storing chamber of a fuel tank curves upward in accordance a decrease in an amount of fuel stored in the fuel storing chamber. The volume of a gaseous space in the fuel storing chamber is reduced, in comparison with a fuel tank in which a lower wall does not deform, by an amount corresponding to a reduction of the volume of the fuel storing chamber achieved by the curvature of the lower wall. An amount of fuel not discharged from the fuel storing chamber via a fuel passage but remaining near a peripheral end portion of the lower wall of the fuel storing chamber due to the upward curvature of the lower wall is discharged via a residual fuel discharging pipe, so that the residual fuel amount of the fuel storing chamber is minimized.

Abstract: According to the invention, a fuel tank for storing a fuel therein is provided. The fuel tank comprises a pair of spaced deformable thin walls and a deformable connecting wall extending between peripheral edges of the thin walls. The connecting wall and the thin walls define a fuel chamber therein. The thin walls and the connecting wall are connected with each other to cause the connecting wall to expand inwardly when the thin walls expand outwardly.

Abstract: The present invention is directed to a plastic part (1) connected to an opening portion (24) of a plastic fuel tank (20). The plastic part (1) includes a body member (30) made of barrier plastic material for preventing the fuel from permeating through the body member (30), and a connecting member (40) made of adhesive plastic material for covering at least a portion of the body member (30) and surrounding the opening portion (24) of the fuel tank (20). The connecting member (40) is formed integrally with the body member (30). The connecting member (40) is connected to the fuel tank (20), with the body member (30) pressed to contact the fuel tank (20) around the opening portion (24). The connecting member (40) has a protrusion (46) formed on a surface of the connecting member (40) connected to the body member (30). As for the protrusion, a step may be formed on an inner side surface of the connecting member (40).

Abstract: According to the invention, a fuel tank for storing a fuel therein is provided. The fuel tank comprises a pair of spaced deformable thin walls and a deformable connecting wall extending between peripheral edges of the thin walls. The connecting wall and the thin walls define a fuel chamber therein. The thin walls and the connecting wall are connected with each other to cause the connecting wall to expand inwardly when the thin walls expand outwardly.

Abstract: The present invention is directed to an opening structure of a fuel tank having a fuel tank wall made of a plurality of plastic layers with an opening portion formed to be integral with the fuel tank wall. The opening structure includes a cylindrical portion extended from the opening portion outward of the fuel tank wall, an overlapping portion extended from an end of the cylindrical portion to enlarge the diameter of the opening portion and bent at a bent portion to form an outer surface parallel with an opening end surface of the opening portion, and a compressed portion with at least a portion of the overlapping portion compressed in a direction perpendicular to the opening end surface of the opening portion. The opening structure may further include an annular member which is disposed around the opening portion to be in contact with the overlapping portion and the cylindrical portion.