Patent attributes
A high pressure tank includes: a resin liner for containing a fluid; and a cap including a supply/discharge hole. A cylindrical portion formed with the liner in a protruding manner is inserted in the supply/discharge hole. In a seal groove formed in an inner circumferential surface of the supply/discharge hole, a seal member and a back-up member disposed on an upstream side of the seal member in the supply direction are provided. A tapered groove surface of the seal groove facing toward the back-up member is apart from the outer circumferential surface of the cylindrical portion along the supply direction. A tapered member surface of the back-up member facing toward the tapered groove surface has a diameter expanding along the supply direction.
