Patent ID: 6863931

Claim:
A method of manufacturing a product having a sprayed coating film, the method comprising: preparing a component having a cylindrical inner surface; preparing a gas spray type spraying gun with a central axis in opposed relationship with the cylindrical inner surface of the component to be aligned with a central axis of the cylindrical inner surface; supplying spraying material to the spraying gun; melting the spraying material with a combustion flame; and traveling the spraying gun for translational movement in a traveling direction, corresponding to one of directions of the central axis of the cylindrical inner surface, and forming a sprayed coating film over the cylindrical inner surface while spraying the spraying material, molten with the combustion flame, onto the cylindrical inner surface in a spraying direction oriented in a rearward area of the traveling direction for thereby obtaining a product having the sprayed coating film on the cylindrical inner surface, wherein the spraying gun includes a first gas flow passage in which a first gas flows to deliver the spraying material, molten with the combustion flame, in one of directions of the central axis and a second gas flow passage in which a second gas flows to deliver the spraying material, delivered in the one of directions, toward a direction intersecting the one of directions, the first and second gas flow passages being comprised of mutually separate systems and a pressure of the second gas being higher than a pressure of the first gas, and wherein the spraying gun is rotated about the central axis during the movement in the cylindrical inner surface.