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US 9,004,542 B2Granted
Pipe fastening structure
AssigneeSanoh Kogyo Kabushiki Kaisha
InventorsHideki Toyoshima, Kazumi Miura, Masakazu Nomura
Life of this patent
Estimating the term…
Abstract
A pipe fastening structure includes an end member attached to an end part of a metal pipe, and a nut for fastening the end member attached to the metal pipe to a counterpart. In the pipe fastening structure, the end member has a first spherical part to be brought into contact with a sealing surface of the counterpart, a second spherical part formed integrally with the first spherical part so as to be in contact with a sliding surface formed in the nut, and a neck continuous with the second spherical part and having the shape of a straight pipe.
Claims14
A pipe fastening structure used in high-pressure fuel lines comprising:
- an end member attached to an end part of a metal pipe;
- a nut for fastening the end part of the metal pipe;
- and
- a counterpart to which the end part of the metal pipe is fastened by the nut;
- wherein the end member has a first spherical part to be brought into contact with a sealing surface formed in the counterpart, a second spherical part formed integrally with the first spherical part so as to be in contact with a sliding surface formed in the nut, and a neck continuous with the second spherical part and having the shape of the metal pipe, an outside diameter D1 of the neck is approximately equal to an outside diameter D of the metal pipe, respective centers of spheres respectively defining the first and the second spherical parts are on an axis of the neck, and the ratio α/β, where α=D2/D, β=D3/D, D is the outside diameter of the metal pipe, D2 is a diameter of a contact circle on the first spherical part in contact with the sealing surface and D3 is a diameter of a contact circle on the second spherical part in contact with the sliding surface of the nut, meets an expression:
- 1.0≧α/β≧0.80,
- such that the end member and the nut do not turn together relative to the counterpart when torque is applied to the nut so that damage to the sealing surface and the sliding surface is prevented;
- and
- a step portion is formed in an inside portion of the nut near a tail end of the nut where the neck is located, wherein the step portion makes a portion of an inner diameter of the nut smaller, and wherein the step portion is adjacent to the neck.
6 more elements
A pipe fastening structure used in high-pressure fuel lines comprising:
- an end member attached to an end part of a metal pipe;
- a nut for fastening the end part of the metal pipe;
- and
- a counterpart to which the end part of the metal pipe is fastened by the nut;
- wherein the end member has a first spherical part to be brought into contact with a sealing surface formed in the counterpart, a second spherical part formed integrally with the first spherical part so as to be in contact with a sliding surface formed in the nut, and a neck continuous with the second spherical part and having the shape of the metal pipe, an outside diameter D1 of the neck is approximately equal to an outside diameter D of the metal pipe, respective centers of spheres respectively defining the first and the second spherical parts are on an axis of the neck, and the ratio α/β, where α=D2/D, β=D3/D, D is the outside diameter of the metal pipe, D2 is a diameter of a contact circle on the first, spherical part in contact with the sealing surface and D3 is a diameter of a contact circle on the second spherical part in contact with the sliding surface of the nut, meets an expression:
- 1.0≧α/β≧0.80,
- such that the end member and the nut do not turn together relative to the counterpart when torque is applied to the nut so that damage to the sealing surface and the sliding surface is prevented;
- and
- wherein the boundary between the first spherical part and the second spherical part is a flat shoulder that is flush with an end surface of the counterpart, the end surface of the counterpart being continuous with the sealing surface of the counterpart.
6 more elements
A pipe fastening structure used in high-pressure fuel lines comprising:
- an end member attached to an end part of a metal pipe;
- a nut for fastening the end part of the metal pipe;
- and
- a counterpart to which the end part of the metal pipe is fastened by the nut;
- wherein the end member has a first spherical part to be brought into contact with a sealing surface formed in the counterpart, a second spherical part formed integrally with the first spherical part so as to be in contact with a sliding surface formed in the nut, and a neck continuous with the second spherical part and having the shape of the metal pipe, an outside diameter D1 of the neck is approximately equal to an outside diameter D of the metal pipe, respective centers of spheres respectively defining the first and the second spherical parts are on an axis of the neck, and the ratio α/β, where α=D2/D, β=D3/D, D is the outside diameter of the metal pipe, D2 is a diameter of a contact circle on the first spherical part in contact with the sealing surface and D3 is a diameter of a contact circle on the second spherical part in contact with the sliding surface of the nut, meets an expression:
- 1.0≧α/β≧0.80,
- such that the end member and the nut do not turn together relative to the counterpart when torque is applied to the nut so that damage to the sealing surface and the sliding surface is prevented;
- and
- wherein an inside surface of an end part of the first spherical part has a thick end part that extends towards the center of a bore formed inside the first spherical part, the thick end part is continuous with a surface of the first spherical part that contacts the sealing surface of the counterpart and creates a flange perpendicular to the inside diameter of the end member.
6 more elements
Dependencies are inferred from the claim text.