Abstract: A heat exchanger includes a tube expansion portion formed by expanding a heat transfer tube so that an outer peripheral surface of the heat transfer tube is pressed against an inner peripheral surface of a hole provided in a side wall portion of a case. The tube expansion portion includes first and second bulge portions positioned respectively on the inside and the outside of the side wall portion so as to sandwich the side wall portion in an axial length direction of the heat transfer tube and configured such that respective outer peripheral surfaces thereof partially bulge outward in a radial direction of the heat transfer tube, an end portion tip end of the heat transfer tube is positioned apart from the second bulge portion, and the end portion tip end and a part in the vicinity thereof are expanded so as to be included in a part of the tube expansion portion.

Abstract: A manufacturing method for a pipe structure includes a pipe bending step for implementing for a plurality of times a bending process of bending a part of a straight pipe by wrapping the part around a peripheral surface of a rolling block to form a plurality of bend portions in intermediate locations along a longitudinal direction of the pipe. When a final bending process is implemented during the pipe bending step, a position of a rear end portion of the pipe is determined, and relative positions of the pipe and the rolling block in a predetermined y direction are controlled on the basis of the position of the rear end portion so that after the bending process, a y-direction position of the rear end portion is aligned with a y-direction position of the front end portion.

Abstract: A heat exchanger includes a tube expansion portion formed by expanding a heat transfer tube so that an outer peripheral surface of the heat transfer tube is pressed against an inner peripheral surface of a hole provided in a side wall portion of a case. The tube expansion portion includes first and second bulge portions positioned respectively on the inside and the outside of the side wall portion so as to sandwich the side wall portion in an axial length direction of the heat transfer tube and configured such that respective outer peripheral surfaces thereof partially bulge outward in a radial direction of the heat transfer tube, an end portion tip end of the heat transfer tube is positioned apart from the second bulge portion, and the end portion tip end and a part in the vicinity thereof are expanded so as to be included in a part of the tube expansion portion.

Abstract: A burner case and a burner device provided with the burner case are disclosed. A cover for closing an opening of a case body of the burner case is attached to the case body by a first caulking portion and a second caulking portion. A first caulking direction and a second caulking direction intersect with each other, the first caulking direction is a direction in which a first attachment piece and a first facing portion, those constituting the first caulking portion, face each other and are caulked, the second caulking direction is a direction in which a second attachment piece and a second facing portion, those constituting the second caulking portion, face each other and are caulked. Thus, the case body and the cover are not required to be screwed or the number of the screws is reduced, and leakage of gas from the burner case to outside is prevented.

Abstract: The burner case has a first member having a caulking portion and a second member having a facing portion facing the caulking portion and an extending portion for caulking, the extending portion extending from the facing portion, the caulking portion being held between the facing portion and the extending portion by bending the extending portion. A part of the extending portion in longitudinal direction constitutes a claw portion. Thus, the first member and the second member are not required to be screwed or the number of screws is reduced, thereby improving productivity of the burner case and reducing the production cost of the burner case.

Abstract: A gas supply manifold has a nozzle forming member having a plurality of gas injection nozzles, a cover member configured to be overlapped on the nozzle forming member, and a caulking-fastening portion configured to fasten the nozzle forming member and the cover member. The caulking-fastening portion is configured such that a convex portion provided for one of the nozzle forming member and the cover member penetrates a hole provided for the other member, and a tip end portion of the convex portion has an engagement portion, the engagement portion having a larger diameter or a larger width than the hole and being engaged with a peripheral edge portion of the hole. A tip end face of the convex portion has a dent portion formed by pressing the tip end face into a base portion side of the convex portion and an area around the dent portion constitutes the engagement portion. Thus, the nozzle forming member and the cover member are appropriately caulked and fastened.

Abstract: The burner case has a first member having a caulking portion and a second member having a facing portion facing the caulking portion and an extending portion for caulking, the extending portion extending from the facing portion, the caulking portion being held between the facing portion and the extending portion by bending the extending portion. A part of the extending portion in longitudinal direction constitutes a claw portion. Thus, the first member and the second member are not required to be screwed or the number of screws is reduced, thereby improving productivity of the burner case and reducing the production cost of the burner case.

Abstract: A burner case and a burner device provided with the burner case are disclosed. A cover for closing an opening of a case body of the burner case is attached to the case body by a first caulking portion and a second caulking portion. A first caulking direction and a second caulking direction intersect with each other, the first caulking direction is a direction in which a first attachment piece and a first facing portion, those constituting the first caulking portion, face each other and are caulked, the second caulking direction is a direction in which a second attachment piece and a second facing portion, those constituting the second caulking portion, face each other and are caulked. Thus, the case body and the cover are not required to be screwed or the number of the screws is reduced, and leakage of gas from the burner case to outside is prevented.

Abstract: A gas supply manifold has a nozzle forming member having a plurality of gas injection nozzles, a cover member configured to be overlapped on the nozzle forming member, and a caulking-fastening portion configured to fasten the nozzle forming member and the cover member. The caulking-fastening portion is configured such that a convex portion provided for one of the nozzle forming member and the cover member penetrates a hole provided for the other member, and a tip end portion of the convex portion has an engagement portion, the engagement portion having a larger diameter or a larger width than the hole and being engaged with a peripheral edge portion of the hole. A tip end face of the convex portion has a dent portion formed by pressing the tip end face into a base portion side of the convex portion and an area around the dent portion constitutes the engagement portion. Thus, the nozzle forming member and the cover member are appropriately caulked and fastened.