Manufacturing method of water heater

Abstract

To provide a water heater and a manufacturing method for the water heater, enabling appropriate attachment of an exhaust hood to a primary heat exchanger even when the exhaust hood is divided into a plurality of members.SOLUTION: A water heater includes an exhaust hood 10 communicating a primary heat exchanger 5 with a secondary heat exchanger 6. The exhaust hood 10 includes a first hood 110 and a second hood 120. A second extension part 112 of the first hood 110 is superposed from the upper side on a front part, a left part and a right part of a first extension part 55 extending outwardly from an opening 515 of an upper end of a peripheral wall 51 of the primary heat exchanger 5. A fourth extension part 123 of the second hood 120 is superposed on the upper side of an extension part 552 so as to cover the whole in the right and left direction of the rear part of the first extension part 55. A first caulking piece part 115 of the first hood 110 and a second caulking piece part 126 of the second hood 120 are disposed over a whole periphery of the first extension part 55 of the peripheral wall 51 of the primary heat exchanger 5.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to salary This relates to a manufacturing method for hot water heaters. [Background technology]

[0002] Conventionally, a latent heat recovery type water heater equipped with a primary heat exchanger and a secondary heat exchanger is known. Patent Document 1 discloses a water heater equipped with an exhaust hood whose lower end is connected to the primary heat exchanger and whose upper end is connected to the secondary heat exchanger. The combustion exhaust gas generated in the combustion device is led from the primary heat exchanger through the exhaust hood to the secondary heat exchanger. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-55929 Summary of the Invention [Problem to be solved by the invention]

[0004] The hood may be divided into a first hood connected to the primary heat exchanger and a second hood connecting the first hood and the secondary heat exchanger. Even in this case, each of the first hood and the second hood needs to be attached to the primary heat exchanger while maintaining airtightness.

[0005] The present invention has been made to solve such problems, and provides a method for properly attaching the exhaust hood to the primary heat exchanger even if the exhaust hood is constructed by dividing it into a plurality of members. Salary The objective is to provide a method for manufacturing a water heater. [Means for solving the problem]

[0006]

[0007] Claim 1The water heater manufacturing method according to the present invention includes a primary heat exchanger having a rectangular cylindrical peripheral wall that communicates exhaust gas from combustion generated in a combustion device from below to above, a secondary heat exchanger having a box-shaped housing and disposed above the primary heat exchanger, and an exhaust hood that communicates the primary heat exchanger and the secondary heat exchanger, the primary heat exchanger having a first extension extending outward from an opening at an upper end of the peripheral wall, the secondary heat exchanger having an inlet in a rear wall of the housing through which the exhaust gas from combustion flows, the exhaust hood having a first hood and a second hood, the first hood being disposed above the first hood, a first main body portion covering the opening of the secondary heat exchanger and bulging upward; a second extending portion extending outward from a front end and left and right ends of the first main body portion and overlapping the front, left and right portions of the first extending portion from above; first crimping piece portions which are a plurality of crimping pieces provided on an outer edge of the second extending portion to crimp the first extending portion; and an abutment portion extending upward, left and right from a rear end of the first main body portion to form an outlet through which the combustion exhaust gas that has passed through the peripheral wall flows out and abutting against the rear wall of the secondary heat exchanger from behind. The second hood covers the outlet and the inlet. a second main body portion having a shape that bulges rearward and has a lower end that is narrowed forward; a third extension portion extending outward from upper and lower ends and left and right ends of the second main body portion and overlapping the rear wall and the abutment portion of the housing from the rear; a fourth extension portion extending rearward from a lower end of the third extension portion and overlapping the entire rear portion of the first extension portion in the left and right direction from above; and second crimping piece portions which are a plurality of crimping pieces provided on an outer edge of the fourth extension portion to crimp the first extension portion, A first direction is a direction corresponding to a front-rear direction when the plate is attached to the primary heat exchanger and the secondary heat exchanger, and a second direction is a direction perpendicular to the first direction. In this case, a first step is to apply a force along the first direction to a metal plate to mold the second main body portion and the third extension portion, and provide a portion corresponding to the second crimping piece portion in a manner extending from an end portion on one side of the second direction to one side of the first direction; and a second step is to apply a force along the first direction to a portion of the third extension portion molded in the first step that is continuous with the portion corresponding to the second crimping piece portion.and a second step of bending a position of the third extension portion that is spaced a predetermined length from a portion of the third extension portion that corresponds to the second crimping piece portion toward the other side of the second direction to form the fourth extension portion and the second crimping piece portion, wherein the second crimping piece portion molded at the end portion of the second hood on one side in the second direction by the first step and the second step extends downward and the second main body portion bulges rearward, and the first hood and the second hood are assembled to the primary heat exchanger and the secondary heat exchanger, and the first crimping piece portion and the second crimping piece portion are disposed around the entire circumference of the first extension portion. Effect of the Invention

[0008] salary The hot water heater is constructed by dividing the exhaust hood into a first hood and a second hood. The second extension of the first hood overlaps from above with the front, left and right parts of the first extension extending outward from the opening at the upper end of the peripheral wall of the primary heat exchanger. The lower end of the second main body of the second hood has a shape that is narrowed toward the front, so that the combustion exhaust that flows out from the outlet into the inside of the second hood is easily guided upward along the shape of the lower end of the second main body to the inlet. Therefore, the efficiency of the heat exchange in the secondary heat exchange is improved. The fourth extension of the second hood overlaps from above with the entire rear part of the first extension in the left-right direction. The first crimping piece provided on the second extension and the second crimping piece provided on the fourth extension are arranged around the entire circumference of the first extension. The first crimping piece and the second crimping piece are crimped to the first extension, thereby ensuring airtightness of the joint between the first hood, the second hood and the first heat exchanger. Therefore, , salary Even if the water heater is configured with a separate exhaust hood, the exhaust hood can be properly attached to the primary heat exchanger.

[0009] If the process of molding the second hood includes a process of applying a force to the metal plate along a first direction and a process of applying a force along a second direction, a process of changing the orientation of the metal plate as the process progresses may become necessary, or the press die may become complicated, which may increase manufacturing costs. In the manufacturing method for a water heater according to the second aspect of the present invention, in both the first and second processes of molding the second hood, a force is applied to the metal plate along a first direction corresponding to the front-to-rear direction in a state in which the first hood, the second hood, the primary heat exchanger, and the secondary heat exchanger are assembled, thereby molding each of the second main body portion, the third extension portion, the fourth extension portion, and the second crimping piece portion. Therefore, the present invention salary The method for manufacturing a water heater can improve the productivity of second hoods having a shape that can be properly attached to a primary heat exchanger. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of the configuration of a water heater 1. FIG. [Diagram 2] 1 is a perspective view of the primary heat exchanger 5, the secondary heat exchanger 6, and the exhaust hood 10 as viewed from the right front. [Diagram 3] 2 is an exploded perspective view of the primary heat exchanger 5, the secondary heat exchanger 6, and the exhaust hood 10 as viewed from the upper right. FIG. [Figure 4] 2 is an exploded perspective view of the primary heat exchanger 5, the secondary heat exchanger 6, and the exhaust hood 10 as viewed from the right rear. FIG. [Diagram 5] 2 is an exploded perspective view of the primary heat exchanger 5, the secondary heat exchanger 6, and the exhaust hood 10 as viewed from the lower right. FIG. [Figure 6] 2 is a right side view of the primary heat exchanger 5, the secondary heat exchanger 6, and the exhaust hood 10. FIG. [Figure 7] 10A to 10C are explanatory views illustrating a molding process of the second hood 120. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described. Unless otherwise specified, the structure of the device described below is not intended to be limited to that, but is merely an explanatory example. The drawings are used to explain technical features that the present invention can employ. In the following description, left and right, front and back, and up and down are indicated by arrows in the drawings.

[0012] The configuration of water heater 1 will be described with reference to Fig. 1. Water heater 1 is a latent heat recovery type gas water heater that heats water taken in from a water pipe and supplies it to the outside, and also circulates and heats hot water in bathtub B. Water heater 1 mainly comprises a fan 3, a combustion device 4, a primary heat exchanger 5, and a secondary heat exchanger 6 inside an inner body 2 housed in a housing not shown. Fan 3 is provided at the bottom of the inner body 2. Fan 3 supplies air into the inside of the inner body 2.

[0013] Combustion device 4 is provided above fan 3 in inner body 2. The inside of combustion device 4 is divided into two chambers by partition member 40. One chamber is provided with hot water supply burner group 41 consisting of a plurality of gas burners, ignition plug 411, and flame rod 412. The other chamber is provided with bath burner group 42 consisting of a plurality of gas burners, ignition plug 421, and flame rod 422. Water heater 1 is provided with gas inlet 11 to which an external gas pipe is connected. Gas inlet 11 is connected to gas distribution unit 12. Gas distribution unit 12 is provided with a gas pipe through which gas supplied from gas inlet 11 flows, and various solenoid valves and distribution pipes for distributing and supplying the gas flowing through the gas pipe to hot water supply burner group 41 and bath burner group 42. Hot water supply burner group 41 ejects a mixture of gas supplied from gas distribution unit 12 and air supplied from fan 3. The mixture is burned in response to ignition of the mixture by ignition plug 411. The bath burner group 42 ejects a mixture of gas supplied from the gas distribution unit 12 and air supplied from the fan 3. When the spark plug 421 ignites the mixture, the mixture burns.

[0014] The primary heat exchanger 5 is provided above the combustion device 4 in the inner body 2. The primary heat exchanger 5 communicates the combustion exhaust gas generated by the combustion of the air-fuel mixture in the combustion device 4 from below to above. The inside of the primary heat exchanger 5 is divided into two chambers by a partition member 50. A first hot water heat transfer pipe 53 is disposed inside one of the chambers. A first bath heat transfer pipe 54 is disposed inside the other chamber. The first hot water heat transfer pipe 53 and the first bath heat transfer pipe 54 are water pipes for recovering sensible heat from the combustion exhaust gas that communicates with the primary heat exchanger 5. In the primary heat exchanger 5, heat exchange is performed in which the thermal energy of the sensible heat contained in the combustion exhaust gas is transferred to the water flowing through the first hot water heat transfer pipe 53 and the first bath heat transfer pipe 54.

[0015] The secondary heat exchanger 6 is provided above the primary heat exchanger 5 and is connected to the primary heat exchanger 5 via the exhaust hood 10. The combustion exhaust gas that has passed through the primary heat exchanger 5 enters the secondary heat exchanger 6 via the exhaust hood 10. The inside of the secondary heat exchanger 6 is divided into two chambers. The second heat transfer pipe 63 for hot water supply is disposed inside one of the chambers. The second heat transfer pipe 64 for bath is disposed inside the other chamber. The second heat transfer pipe 63 for hot water supply and the second heat transfer pipe 64 for bath are water pipes for recovering latent heat from the combustion exhaust gas that communicates with the secondary heat exchanger 6. In the secondary heat exchanger 6, heat exchange is performed in which the thermal energy of the latent heat of the combustion exhaust gas is transferred to the water flowing through the second heat transfer pipe 63 for hot water supply and the second heat transfer pipe 64 for bath. The combustion exhaust gas after the latent heat is recovered is exhausted from the exhaust pipe 69 that communicates with the exhaust port 68.

[0016] The water heater 1 includes a water inlet 13, a water supply section 14, a water supply pipe 71, a relay pipe 81, a water outlet pipe 91, a bypass pipe 101, a water outlet section 15, and a water outlet 16. An external water pipe is connected to the water inlet 13. The water inlet 13 is connected to the water supply section 14. The water supply section 14 includes a motor for flow control, a water flow sensor, an inlet water temperature sensor, and the like. The water supply pipe 71 is a water pipe that connects the water supply section 14 and the second hot water heat transfer pipe 63. The relay pipe 81 is a water pipe that connects the second hot water heat transfer pipe 63 and the first hot water heat transfer pipe 53. The water outlet pipe 91 is a water pipe that connects the first hot water heat transfer pipe 53 and the water outlet section 15. The bypass pipe 101 is a water pipe that connects the water supply section 14 and the water outlet pipe 91 without passing through the primary heat exchanger 5 and the secondary heat exchanger 6. The water outlet 15 is equipped with a hot water temperature sensor, etc. The water outlet 16 is connected to the water outlet 15, and supplies hot water at an appropriate temperature, which is a mixture of hot water flowing through the water outlet pipe 91 and water supplied from the bypass pipe 101, to the outside.

[0017] The water heater 1 includes a hot water inlet 721, a pump 72, a water supply pipe 722, a relay pipe 82, a hot water outlet pipe 92, and a hot water outlet 921. The hot water inlet 721 is connected to an external bathtub B, and draws in hot water from inside the bathtub B in response to the operation of the pump 72. The water supply pipe 722 is a water pipe that connects the pump 72 and the second bath heat transfer pipe 64. The relay pipe 82 is a water pipe that connects the second bath heat transfer pipe 64 and the first bath heat transfer pipe 54. The hot water outlet pipe 92 is a water pipe that connects the first bath heat transfer pipe 54 and the hot water outlet 921. The hot water outlet 921 is connected to the bathtub B, and discharges hot water that is heated in the primary heat exchanger 5 and the secondary heat exchanger 6 and flows through the hot water outlet pipe 92 into the bathtub B.

[0018] The water heater 1 also includes drain pipes 661, 662 and a neutralizer 66. The drain pipe 6661 connects a drain outlet 663 provided at the bottom of the secondary heat exchanger 6 to the neutralizer 66. Drain generated by recovery of latent heat in the secondary heat exchanger 6 is discharged from the drain outlet 663 to the outside of the secondary heat exchanger 6 and sent to the neutralizer 66 via the drain pipe 661. The drain sent to the neutralizer 66 is neutralized in the neutralizer 66 and discharged to the outside of the water heater 1 via the drain pipe 662.

[0019] The configurations of the primary heat exchanger 5, the secondary heat exchanger 6, and the exhaust hood 10 will be described with reference to Figs. 2 to 4. The primary heat exchanger 5 includes a rectangular cylindrical peripheral wall 51 extending in the vertical direction. The peripheral wall 51 is made of a metal having excellent heat transfer properties, and constitutes a part of the inner body 2. The peripheral wall 51 includes a front wall 511, a rear wall 512, a left wall 513, and a right wall 514. The lower ends of the front wall 511, the rear wall 512, the left wall 513, and the right wall 514 each form a rectangular opening 517 at the lower part of the peripheral wall 51. The peripheral wall 51 is connected to an opening at the upper part of the square box-shaped combustion device 4 at an edge part 518 extending outward from the opening 517. The peripheral wall 51 communicates the combustion exhaust gas generated by the combustion of the air-fuel mixture in the combustion device 4 from below to above. Inside the peripheral wall 51, the first hot water heat transfer pipe 53 and the first bath heat transfer pipe 54 shown in Fig. 1 are arranged so as to reciprocate multiple times in the front-to-rear direction. Of the multiple through holes provided in the front wall 511 and the rear wall 512, the first hot water heat transfer pipe 53 is arranged in the seven through holes on the right side, and the first bath heat transfer pipe 54 is arranged in the three through holes on the left side. In order to clearly show the configuration of the peripheral wall 51, the first hot water heat transfer pipe 53 and the first bath heat transfer pipe 54 are not shown in Figs. 2 to 5.

[0020] As shown in FIG. 3 and FIG. 4, the upper ends of the front wall 511, the rear wall 512, the left wall 513, and the right wall 514 each form a rectangular opening 515 in the upper part of the peripheral wall 51. The combustion exhaust gas after the sensible heat is recovered in the primary heat exchanger 5 flows upward from the opening 515. A first extension portion 55 extending outward from the opening 515 is provided on the periphery of the opening 515. The first extension portion 55 includes extension portions 551, 552, 553, and 554. The extension portion 551 extends substantially horizontally forward from the upper end of the front wall 511. The extension portion 552 extends substantially horizontally rearward from the upper end of the rear wall 512. The extension portion 553 extends substantially horizontally from the upper end of the left wall 513 toward the left. The extension portion 554 extends substantially horizontally from the upper end of the right wall 514 toward the right.

[0021] The secondary heat exchanger 6 includes a housing 61 made of a metal having excellent heat conductivity, and constitutes a part of the inner body 2. The housing 61 includes an upper wall 611, a lower wall 612, a left wall 613, a right wall 614, a front wall 615, and a rear wall 616 shown in FIG. 4. The widths of the upper wall 611, the lower wall 612, the front wall 615, and the rear wall 616 in the left-right direction are approximately the same as the width of the primary heat exchanger 5 in the left-right direction. The widths of the upper wall 611, the lower wall 612, the left wall 613, and the right wall 614 in the front-rear direction are longer than the width of the primary heat exchanger 5 in the front-rear direction. The rear wall 616 is disposed at approximately the same position as the rear of the combustion device 4, and the front of the housing 61 is disposed to protrude forward from the front of the primary heat exchanger 5.

[0022] As shown in Fig. 4, the inside of the housing 61 is divided into two chambers, and in the right chamber, the second hot water heat transfer pipe 63 is arranged so as to reciprocate multiple times in the left-right direction. In the left chamber, the second bath heat transfer pipe 64 is arranged so as to reciprocate multiple times in the left-right direction. A connection part 631 where the upstream end of the second hot water heat transfer pipe 63 is arranged is provided in the front lower part of the right wall 614. A connection part 632 where the downstream end of the second hot water heat transfer pipe 63 is arranged is provided in the rear upper part of the right wall 614. Although not shown, the left wall 613 is provided with connection parts where the upstream end and downstream end of the second bath heat transfer pipe 64 are respectively arranged.

[0023] Inlets 617, 618, which are rectangular openings for allowing the combustion exhaust gas to flow into the housing 61, are provided side by side in the center of the rear wall 616. The right inlet 617 is provided corresponding to the room on the side where the second hot water heat transfer pipe 63 is arranged. The left inlet 618 is provided corresponding to the room on the side where the second bath heat transfer pipe 64 is arranged. Above the inlets 617, 618, screw holes 11D, 11E, 11F, and 11G are provided side by side from the left.

[0024] 2, a rectangular exhaust port 68 extending in the left-right direction is provided in the center of front wall 615. The exhaust gas from combustion after latent heat recovery in secondary heat exchanger 6 is exhausted from exhaust port 68. An exhaust pipe 69 is fixed to front wall 615 from the front side so as to communicate with exhaust port 68. Exhaust pipe 69 exhausts the exhaust gas from combustion flowing out from exhaust port 68 to the outside of water heater 1.

[0025] The exhaust hood 10 is a member that covers the opening 515 in the peripheral wall 51 of the primary heat exchanger 5 from above and connects the primary heat exchanger 5 and the secondary heat exchanger 6, and constitutes a part of the inner body 2. The exhaust hood 10 includes a first hood 110 and a second hood 120. The first hood 110 is made of a metal with excellent heat conductivity, and constitutes the front portion of the exhaust hood 10. The second hood 120 constitutes the rear portion of the exhaust hood 10.

[0026] 3 and 4, the first hood 110 includes a first main body portion 111, a second extending portion 112, a first crimping piece portion 115, a contact portion 116, and a contact frame 117. The first main body portion 111 has a shape that bulges upward. The first main body portion 111 covers the opening 515 of the peripheral wall 51 of the primary heat exchanger 5 from above. The second extending portion 112 is a portion that extends outwardly from the front end, left end, and right end of the first main body portion 111 approximately horizontally.

[0027] A plurality of crimping pieces 113 are provided at a predetermined interval on the outer edge of the second extending portion 112. Each of the crimping pieces 113 extends downward and has a through hole in the center thereof into which a crimping pin (not shown) is inserted. Hereinafter, a set of the plurality of crimping pieces 113 provided on the outer edge of the second extending portion 112 is referred to as a first crimping piece portion 115.

[0028] As shown in Figs. 3 and 4, the abutment portion 116 is a portion extending from the rear end of the first main body portion 111 toward the upper, left, and right in a substantially vertical direction. As shown in Fig. 4, the abutment portion 116 extends at a position forward of the rear wall 512 of the peripheral wall 51 of the primary heat exchanger 5. As shown in Fig. 4, the portion where the abutment portion 116 and the first main body portion 111 are continuous forms an outlet 114 which is an opening that opens in an arch shape toward the rear. The outlet 114 causes the combustion exhaust gas guided into the second extension portion 112 and the inside of the first main body portion 111 to flow out to the rear of the first hood 110. The front surface of the abutment portion 116 abuts against the rear wall 616 of the secondary heat exchanger 6 from the rear. On the left part of the abutment portion 116, screw holes 11A, 11B, and 11C are provided in a line from the bottom. On the right side of the abutting portion 116, screw holes 11H, 11I, and 11J are provided in line from the top.

[0029] A partition member 50 is attached to a position slightly to the left of the center of the abutment portion 116. The partition member 50 is a plate-shaped member that divides the inside of the exhaust hood 10 into two chambers. The chamber on the left side of the partition member 50 corresponds to the chamber located above the area in the primary heat exchanger 5 where the first bath heat transfer pipe 54 is located, and the chamber on the right side of the partition member 50 corresponds to the chamber located above the area in the primary heat exchanger 5 where the first hot water heat transfer pipe 53 is located.

[0030] The contact frame 117 is a portion that extends approximately horizontally rearward at the same position in the up-down direction as the second extending portion 112, rearward of the contact portion 116. The shape of the contact frame 117 corresponds to the shape of the extending portion 552 of the first extending portion 55.

[0031] As shown in Figs. 3 and 4, the second hood 120 has a rectangular shape that is long in the left-right direction in a rear view. The second hood 120 includes a second main body portion 121, a third extending portion 122, a fourth extending portion 123, and a second crimping piece portion 126. The second main body portion 121 has a shape that bulges rearward and constitutes the main body portion of the second hood 120. The second main body portion 121 has a shape that bulges rearward most at its center and is narrowed forward as it moves outward from the center. The third extending portion 122 is a surface portion that extends substantially vertically outward from the upper end, lower end, left end, and right end of the second main body portion 121 and constitutes the periphery of the second main body portion 121. The upper end portion of the third extending portion 122 is slightly folded back rearward to reinforce the upper portion of the third extending portion 122. Screw holes 12A, 12B, and 12C are provided in a row from bottom to top on the left side of the third extending portion 122. Screw holes 12D, 12E, 12F, and 12G are provided in a row from left to top on the top of the third extending portion 122. Screw holes 12H, 12I, and 12J are provided in a row from top to bottom on the right side of the third extending portion 122.

[0032] As shown in FIG. 4, the fourth extending portion 123 is a portion that extends rearward from the lower end of the third extending portion 122 in a substantially horizontal manner. The fourth extending portion 123 extends across the entire lower portion of the second hood 120 in the left-right direction. A plurality of crimping pieces 125 are provided at a predetermined interval on the outer edge of the fourth extending portion 123. Each of the crimping pieces 125 extends downward and has a through hole in its center into which a crimping pin (not shown) is inserted. Hereinafter, a set of the plurality of crimping pieces 125 provided on the outer edge of the fourth extending portion 123 will be referred to as a second crimping piece 126.

[0033] An example of a method for assembling the primary heat exchanger 5, the exhaust hood 10, and the secondary heat exchanger 6 will be described with reference to Figs. 3 to 5. As shown in Figs. 3 and 4, the first hood 110 of the exhaust hood 10 is assembled to the primary heat exchanger 5. The second extension portion 112 of the first hood 110 is assembled so as to overlap from above with the first extension portion 55 provided on the periphery of the opening 515 of the peripheral wall 51 of the primary heat exchanger 5. The front portion 13A of the second extension portion 112 extending forward from the front end of the first main body portion 111 overlaps from above with the extension portion 551 of the first extension portion 55. The left portion 13B of the second extension portion 112 extending leftward from the left end of the first main body portion 111 overlaps from above with the extension portion 552 of the first extension portion 55. A right portion 13C of the second extending portion 112 extending rightward from the right end of the first main body portion 111 overlaps with the extending portion 553 of the first extending portion 55 from above. Moreover, the abutment frame 117 overlaps with the extending portion 553 of the first extending portion 55 of the peripheral wall 51 of the primary heat exchanger 5 from above. This positions the second extending portion 112 and the abutment frame 117 of the first hood 110 with respect to the first extending portion 55 of the peripheral wall 51. Moreover, a state is formed in which the first main body portion 111 of the first hood 110 covers the opening 515 of the peripheral wall 51 from above.

[0034] At the center of the front portion 13A, fixing portions 118, 119 are provided for screwing and fixing a support member 67 for supporting the front portion of the secondary heat exchanger 6 relative to the first hood 110. The support member 67 is a plate-like member that is L-shaped in a side view, and includes a first portion 671 extending in the vertical direction and a second portion 672 extending forward from an upper end of the first portion 671.

[0035] The first portion 671 of the support member 67 abuts against the front portion of the bottom wall 612 of the housing 61 from below. A screw hole 673 on the left side of the first portion 671 is screwed into the fixing portion 118. A screw hole 674 on the right side of the first portion 671 is screwed into the fixing portion 119. This supports the front portion of the secondary heat exchanger 6 against the first hood 110. In addition, the front surface of the abutment portion 116 of the first hood 110 abuts against the rear wall 616 of the secondary heat exchanger 6 from behind, so that the abutment portion 116 and the rear wall 616 of the secondary heat exchanger 6 are arranged side by side at approximately the same position in the front-to-rear direction.

[0036] In this state, the second hood 120 is assembled to the rear of the first hood 110 and the secondary heat exchanger 6. The fourth extending portion 123 of the second hood 120 is overlapped from above with the extending portion 552 of the first extending portion 55 of the primary heat exchanger 5 via the abutment frame 117 of the first hood 110. The fourth extending portion 123 is overlapped with the extending portion 552 so as to cover the entire extending portion 552 in the left-right direction. A plurality of crimping pieces 125 provided on the outer edge of the fourth extending portion 123 are arranged along the outer edge of the extending portion 552.

[0037] An upper portion of the third extending portion 122 overlaps with the rear wall 616 of the housing 61 of the secondary heat exchanger 6 from the rear side via a packing (not shown). A lower portion of the third extending portion 122 overlaps with the abutting portion 116 of the first hood 110 from the rear side via a packing (not shown). Screw holes 12A, 12B, 12C on the left side of the third extending portion 122 are respectively overlapped with screw holes 11A, 11B, 11C on the left side of the abutting portion 116 and are screwed together. Screw holes 12D, 12E, 12F, 12G on the upper portion of the third extending portion 122 are respectively overlapped with screw holes 11D, 11E, 11F, 11G on the upper portion of the rear wall 616 of the housing 61 and are screwed together. The screw holes 12H, 12I, 12J on the right side of the third extending portion 122 are respectively overlapped with the screw holes 11H, 11I, 11J on the right side of the abutting portion 116, and are screwed together. This results in a state in which the second main body portion 121 of the second hood 120 covers the outlet 114 of the first hood 110 and the inlets 617, 618 of the rear wall 616 of the housing 61 from the rear.

[0038] In this state, as shown in FIG. 5, the multiple crimping pieces 113 provided on the outer edge of the front portion 13A of the second extending portion 112 of the first hood 110 are arranged along the outer edge of the extending portion 551 of the first extending portion 55 of the peripheral wall 51 of the primary heat exchanger 5. The multiple crimping pieces 113 provided on the outer edge of the left portion 13B shown in FIG. 3 are arranged along the outer edge of the extending portion 553 of the first extending portion 55 shown in FIGS. 3 and 4. The multiple crimping pieces 113 provided on the outer edge of the right portion 13C are arranged along the outer edge of the extending portion 554 of the first extending portion 55. That is, the first crimping piece portion 115 is arranged around the extending portions 551, 553, and 554 of the first extending portion 55 of the peripheral wall 51 of the primary heat exchanger 5. 3 and 4 of the first extending portion 55. In other words, in a state in which the first hood 110 and the second hood 120 are assembled to the primary heat exchanger 5 and the secondary heat exchanger 6, the first crimping piece 115 and the second crimping piece 126 are arranged around the entire circumference of the first extending portion 55 of the peripheral wall 51 of the primary heat exchanger 5.

[0039] Each of the multiple crimping pieces 113 constituting the first crimping piece portion 115 is bent inward along the extending portions 551, 553, and 554, respectively, and is crimped to each of the extending portions 551, 553, and 554. In addition, each of the multiple crimping pieces 125 constituting the second crimping piece portion 126 is also bent inward along the outer edge of the extending portion 552, and is crimped to the extending portion 552. As a result, the second extending portion 112 of the first hood 110 and the fourth extending portion 123 of the second hood 120 are firmly joined to the first extending portion 55 of the peripheral wall 51 of the primary heat exchanger 5, and airtightness between the first hood 110, the second hood 120, and the primary heat exchanger 5 is ensured. In other words, even if the exhaust hood 10 of the water heater 1 is constructed by dividing it into two components, the first hood 110 and the second hood 120, the first hood 110 and the second hood 120 can be appropriately attached to the primary heat exchanger 5.

[0040] With reference to FIG. 6, the manner in which the combustion exhaust gas passes through the primary heat exchanger 5 and the exhaust hood 10 and is guided to the secondary heat exchanger 6 will be described. As indicated by the arrow Y1, the combustion exhaust gas generated in the combustion device 4 flows from the bottom to the top inside the peripheral wall 51 of the primary heat exchanger 5, and flows out from the opening 515 shown in FIG. 3 and FIG. 5 into the inside of the first hood 110. The combustion exhaust gas that flows into the inside of the first hood 110 flows out from the outlet 114 shown in FIG. 4 and FIG. 5, and flows into the inside of the second hood 120. The lower part of the second main body part 121 of the second hood 120 has a shape that is narrowed forward. Therefore, the combustion exhaust gas that flows into the inside of the second hood 120 flows upward along the shape of the lower part of the second main body part 121. The combustion exhaust gas that flows toward the upper part of the second main body part 121 flows into the inside of the secondary heat exchanger 6 from the inlets 617, 618 of the rear wall 616 shown in FIG. 4 of the housing 61 of the secondary heat exchanger 6. That is, the exhaust combustion air that flows from first hood 110 into second hood 120 flows smoothly upward inside second main body portion 121 of second hood 120 along the narrowed shape of the lower part of second main body portion 121, so that pressure loss is unlikely to occur in the exhaust combustion air inside second hood 120. Therefore, the exhaust combustion air can move inside second hood 120 while retaining sufficient thermal energy, and flow into secondary heat exchanger 6. Therefore, the water heater 1 can improve the efficiency of heat exchange in secondary heat exchanger 6.

[0041] The molding process of the second hood 120 will be described with reference to FIG. 7. The second hood 120 is molded by pressing the metal plate 100 using a press machine to which a die is fixed. The die used in this molding process includes an upper die 210 and a lower die 220. The upper die 210 is fixed to a slide that moves up and down in the press machine. The lower die 220 is fixed to a bolster whose position in the first direction is fixed in the press machine. The upper die 210 includes a split die 21A that can move independently from one side to the other in the first direction relative to the upper die 210. The lower die 220 includes a split die 22A that can move independently from one side to the other in the first direction relative to the lower die 220. The first direction in this molding process is the up-down direction, and one side of the first direction corresponds to the upper side, and the other side of the first direction corresponds to the lower side. The first direction corresponds to the front-rear direction in a state in which the second hood 120, which is a finished product obtained by the molding process, is attached to the primary heat exchanger 5 and the secondary heat exchanger 6. One side of the first direction corresponds to the front side in a state in which the second hood 120 is attached to the primary heat exchanger 5 and the secondary heat exchanger 6, and the other side of the first direction corresponds to the rear side in a state in which the second hood 120 is attached to the primary heat exchanger 5 and the secondary heat exchanger 6.

[0042] The direction perpendicular to the first direction is the second direction. The second direction in this molding process is the left-right direction, with one side of the second direction corresponding to the left side and the other side of the first direction corresponding to the right side. The second direction corresponds to the up-down direction in the state in which the second hood 120, which is a finished product by the molding process, is assembled to the primary heat exchanger 5 and the secondary heat exchanger 6. One side of the second direction corresponds to the lower side in the state in which the second hood 120 is assembled to the primary heat exchanger 5 and the secondary heat exchanger 6, and the other side of the first direction corresponds to the upper side in the state in which the second hood 120 is assembled to the primary heat exchanger 5 and the secondary heat exchanger 6. In order to explain the shape molded in this molding process, the sheet metal 100, the intermediate product 109 being molded, the finished second hood 120, the upper mold 210, and the lower mold 220 are each shown in a cross-sectional view in FIG. 7.

[0043] When the molding process of the second hood 120 is started, an operator prepares the metal sheet 100 shown in FIG. 7(1) and inserts the metal sheet 100 between the upper die 210 and the lower die 220 as shown in FIG. 7(2). The upper die 210 has parts 21B, 21C, 21D, 21E, and 21F as parts of the other side surface in the first direction. The part 21B is a substantially horizontal surface part that is disposed at the other position in the first direction of the upper die 210. The part 21B is provided to mold the folded-back part of the upper part of the third extension part 122 of the second hood 120 by the step with the part 21C. The part 21C is a substantially horizontal surface part that is adjacent to the part 21B on one side in the second direction and disposed on one side in the first direction than the part 21B. The part 21C is a part that corresponds to the upper shape of the third extension part 122 of the second hood 120. The portion 21D is adjacent to the portion 21C on one side in the second direction. The portion 21D is a portion that protrudes toward the other side in the first direction in response to the bulging shape of the second main body portion 121 of the second hood 120. The portion 21E is adjacent to the portion 21D on one side in the second direction and is a surface portion that extends substantially horizontally continuous with the upper end portion of the portion 21D. The split mold 21A is disposed in a portion of the portion 21E that is slightly spaced from the portion 21D on one side in the second direction. When the molding process of the second hood 120 is started, the lower surface of the split mold 21A is disposed side by side with the portion 21E at the same position in the first direction. The portion 21C and the portion 21E are disposed at the same position in the first direction. The portion 21F is adjacent to the portion 21E on one side in the second direction and is a substantially horizontal surface portion that is disposed on one side in the first direction from the portion 21E. The portion 21F is a portion provided for molding a portion 128 that corresponds to a second crimping piece portion of the intermediate product 109 described later.

[0044] The lower mold 220 includes the parts 22B, 22C, 22D, 22E, and 22F as parts of one side surface in the first direction. The part 22B faces the part 21B of the upper mold 210. The part 22B is a substantially horizontal surface part disposed at the other position of the lower mold 220 in the first direction. The part 22C faces the part 21C of the upper mold 210. The part 22C is a substantially horizontal surface part adjacent to one side of the part 22B in the second direction and disposed on one side of the part 22B in the first direction. The part 22D faces the part 21D of the upper mold 210. The part 22D is adjacent to one side of the part 22C in the second direction. The part 22D is a part that is recessed to the other side of the first direction in response to the bulging shape of the second main body part 121 of the second hood 120. Part 22E is a part facing part 21E of upper mold 210. Part 22E is adjacent to one side of part 22D in the second direction, and is a surface portion extending substantially horizontally continuous with the upper end of part 22D. Split mold 22A is placed in part 22E. When the molding process of second hood 120 is started, the upper surface of split mold 22A constitutes part 22E. When the molding process of second hood 120 is started, part 22C and part 22E are placed at the same position in the first direction. Part 22F is a part facing part 21F of upper mold 210. Part 22F is adjacent to one side of part 22E in the second direction, and extends substantially horizontally in one side of the first direction further than part 22E.

[0045] In the next step, as shown in FIG. 7(3), the worker moves the upper die 210 from one side to the other in the first direction to bring it close to the lower die 220, and applies a force F from one side to the other in the first direction to the metal sheet 100. As a result, the metal sheet 100 is shaped to match the shapes of the upper die 210 and the lower die 220, and an intermediate product 109 is obtained. The intermediate product 109 includes a third extension portion 122, a second main body portion 121, a middle portion 127, and a portion 128. The third extension portion 122 in the intermediate product 109 is formed by pressing the metal sheet 100 between the portion 22C of the lower die 220 and the portion 21C of the upper die 210. The third extension portion 122 in the intermediate product 109 corresponds to the portion of the third extension portion 122 in the second hood 120 of the completed product, which extends outward from the upper end, left end, and right end of the second main body portion 121. The second main body portion 121 is formed by pressing the metal plate 100 between the portion 22D of the lower mold 220 and the portion 21D of the upper mold 210.

[0046] The intermediate portion 127 is formed by pressing the metal plate 100 between the portion 22E of the lower die 220 and the portion 21E of the upper die 210. The intermediate portion 127 is a portion including a portion of the third extension portion 122 in the second hood 120 of the completed product that extends outward from the lower end of the second main body portion 121 and a portion corresponding to the fourth extension portion 123. In the process shown in FIG. 7(3), the intermediate portion 127 extends substantially horizontally at the same position in the first direction as the third extension portion 122. The portion 128 is formed by pressing the end of the metal plate 100 arranged across the portion 22E and the portion 22F of the lower die 220 by the portion 21E and the portion 22F of the upper die 210. The portion 128 is formed in a state where the end of the intermediate portion 127 opposite to the second main body portion 121 is bent perpendicularly to the intermediate portion 127. The portion 128 is a portion that constitutes the second crimping piece 126 in the completed second hood 120 .

[0047] In the next step, as shown in FIG. 7(4), the worker moves the split mold 21A built in the upper mold 210 from one side to the other in the first direction to project it from the portion 21E. The worker also moves the split mold 22A built in the lower mold 220 from one side to the other in the first direction to collapse the portion 22E. A force F from one side to the other in the first direction is applied to a portion of the intermediate portion 127 adjacent to the portion 128. As a result, at a position of the intermediate portion 127 spaced a predetermined length from the portion 128 on the other side in the second direction, the portion of the intermediate portion 127 continuing to the portion 128 is bent perpendicularly to the portion of the intermediate portion 127 continuing to the second main body portion 121. The portion of the intermediate portion 127 adjacent to the second main body portion 121 forms a portion of the third extension portion 122 in the second hood 120 of the finished product, which extends outward from the lower end of the second main body portion 121. A portion of intermediate portion 127 adjacent to portion 128 forms fourth extending portion 123. Portion 128 extends perpendicular to fourth extending portion 123 at the outer edge of the formed fourth extending portion 123, forming second crimping piece portion 126. Thus, second hood 120 is completed as shown in FIG. 7(5).

[0048] If the process of molding a press-formed product includes a process of applying a force along a first direction to the metal sheet and a process of applying a force along a second direction, a process of changing the orientation of the metal sheet relative to the die is required as the process progresses. The molding process of the second hood 120 can mold the finished second hood 120 via the intermediate product 109 by applying a force F along the first direction to the metal sheet 100 using the upper die 210 and the lower die 220 without applying a force along the second direction to the metal sheet 100. That is, the molding process of the second hood 120 can improve the productivity of the second hood 120.

[0049] As described above, the water heater 1 includes the exhaust hood 10 that communicates the primary heat exchanger 5 and the secondary heat exchanger 6. The exhaust hood 10 is divided into the first hood 110 and the second hood 120. The second extension portion 112 of the first hood 110 overlaps from above with the extension portions 551, 553, and 554 that constitute the front, left, and right portions of the first extension portion 55 that extends outward from the opening 515 at the upper end of the peripheral wall 51 of the primary heat exchanger 5. Since the lower end of the second main body portion 121 of the second hood 120 has a shape that is narrowed toward the front, the combustion exhaust gas that flows out from the outlet 114 of the first hood 110 to the inside of the second hood 120 moves upward inside the second main body portion 121 along the shape of the lower end of the second main body portion 121. Therefore, the combustion exhaust gas inside the second main body portion 121 is efficiently guided to the inlets 617 and 618 of the secondary heat exchanger 6. The fourth extending portion 123 of the second hood 120 is overlapped above the extending portion 552 so as to cover the entire extending portion 552 constituting the rear portion of the first extending portion 55 in the left-right direction. As a result, the first crimping piece 115 of the first hood 110 and the second crimping piece 126 of the second hood 120 are arranged around the entire circumference of the first extending portion 55 of the peripheral wall 51 of the primary heat exchanger 5. Each of the multiple crimping pieces 113 constituting the first crimping piece 115 is crimped to the extending portions 551, 552, and 553. The multiple crimping pieces 125 constituting the second crimping piece 126 is crimped to the extending portion 551. This firmly bonds the second extension portion 112 of the first hood 110 and the fourth extension portion 123 of the second hood 120 to the first extension portion 55 of the peripheral wall 51 of the primary heat exchanger 5, ensuring airtightness between the first hood 110 and the second hood 120 and the primary heat exchanger 5. In this way, even if the exhaust hood 10 of the water heater 1 is configured to be separated into the first hood 110 and the second hood 120, the exhaust hood 10 can be appropriately attached to the primary heat exchanger 5.

[0050] When the molding process of the parts of the water heater 1 such as the second hood 120 includes a process of applying a force to the sheet metal along a first direction and a process of applying a force along a second direction perpendicular to the first direction, it becomes necessary to change the orientation of the sheet metal as the process progresses. In addition, the manufacturing cost of the parts may increase due to the complicated shape of the mold. The molding process of the second hood 120 of the water heater 1 includes a first process of applying a force F from one side to the other side in the first direction to the sheet metal 100 to mold an intermediate product 109 including a third extension portion 122, a second main body portion 121, an intermediate portion 127, and a portion 128. In addition, in the second process, a force F from one side to the other side in the first direction is applied to the intermediate portion 127 to bend the intermediate portion 127 vertically at a position spaced a predetermined length from the portion 128 to the other side in the second direction. In response to this, a portion of the third extension portion 122 extending outward from the lower end of the second main body portion 121 and a fourth extension portion 123 are formed. As a result, portion 128 extends perpendicularly to fourth extending portion 123 at the outer edge of the formed fourth extending portion 123, forming second crimping piece 126. In either process, force F is applied to sheet metal 100 and intermediate product 109 in the direction from one side to the other side in the first direction, thereby improving the productivity of second extending portion 120.

[0051] In this embodiment, the water heater 1 corresponds to the "water heater" of the present invention. The combustion device 4 corresponds to the "combustion device" of the present invention. The primary heat exchanger 5 corresponds to the "primary heat exchanger" of the present invention. The peripheral wall 51 corresponds to the "peripheral wall" of the present invention. The opening 515 corresponds to the "opening" of the present invention. The first extension portion 55 corresponds to the "first extension portion" of the present invention. The secondary heat exchanger 6 corresponds to the "secondary heat exchanger" of the present invention. The housing 61 corresponds to the "housing" of the present invention. The inlets 617, 618 correspond to the "inlet" of the present invention. The exhaust hood 10 corresponds to the "exhaust hood" of the present invention. The first hood 110 corresponds to the "first hood" of the present invention. The first main body portion 111 corresponds to the "first main body portion" of the present invention. The second extension portion 112 corresponds to the "second extension portion" of the present invention. The first crimping piece portion 115 corresponds to the "first crimping piece portion" of the present invention. The abutting portion 116 corresponds to the "abutting portion" of the present invention. The outlet 114 corresponds to the "outlet" of the present invention. The second hood 120 corresponds to the "second hood" of the present invention. The second main body portion 121 corresponds to the "second main body portion" of the present invention. The third extension portion 122 corresponds to the "third extension portion" of the present invention. The fourth extension portion 123 corresponds to the "fourth extension portion" of the present invention. The second crimping piece portion 126 corresponds to the "second crimping piece" of the present invention. The process shown in Figure 7 (3) corresponds to the "first process" of the present invention. The process shown in Figure 7 (4) corresponds to the "second process" of the present invention.

[0052] The present invention is not limited to the above embodiment, and various modifications are possible. For example, the water heater 1 is not limited to a gas water heater, and may be an oil water heater, etc. In addition, the water heater 1 includes both a water pipe circuit for hot water supply and a water pipe circuit for a bath, but may include only one of the circuits. In addition, the water heater 1 may include another water pipe circuit for heating, etc.

[0053] The number of the multiple crimping pieces 113 constituting the first crimping piece portion 115 and the number of the multiple crimping pieces 125 constituting the second crimping piece portion 126 may be changed arbitrarily in order to ensure airtightness between the primary heat exchanger 5 and the exhaust hood 10. The intervals between the multiple crimping pieces 113 constituting the first crimping piece portion 115 may be equal or may not be equal. The intervals between the multiple crimping pieces 125 constituting the second crimping piece portion 126 may be equal or may not be equal. In addition, the intervals between the multiple crimping pieces 113 and the intervals between the multiple crimping pieces 125 may be the same or different.

[0054] In the molding process of the second hood 120, the upper die 210 and the lower die 220 may be inverted in the up-down relationship. That is, the upper die 210 may be fixed to a bolster of a press machine, the lower die 220 may be fixed to a slide of the press machine, and the lower die 220 may be brought closer to the upper die 210 from above to below, thereby pressing the metal plate 100 to mold the second hood 120. In addition, the direction in which the upper die 210 and the lower die 220 approach each other, i.e., the first direction, is not limited to the up-down direction. Therefore, the first direction may be the left-right direction, and the force F applied to the metal plate 100 and the intermediate product 109 in the molding process of the second hood 120 may be a force along the left-right direction. [Explanation of symbols]

[0055] 1. Water heater 4 Combustion equipment 5 Primary heat exchanger 6 Secondary heat exchanger 10 Exhaust hood 51 Peripheral wall 55 First extension 61 Case 110 First Food 111 First body part 112 Second extension part 114 Outlet 115 First crimping piece 116 Contact part 120 Second Food 121 Second body part 122 The third extension 123 Fourth extension 515 Opening 617,618 Inlet

Claims

[Claim 1] a primary heat exchanger having a rectangular cylindrical peripheral wall that communicates the combustion exhaust gas generated in the combustion device from below to above; A secondary heat exchanger having a box-shaped housing and disposed above the primary heat exchanger; an exhaust hood that communicates the primary heat exchanger and the secondary heat exchanger; Equipped with The primary heat exchanger includes a first extension portion extending outward from an opening at an upper end of the peripheral wall, The secondary heat exchanger includes an inlet for allowing combustion exhaust gas to flow in the rear wall of the housing, The exhaust hood comprises a first hood and a second hood, The first hood is A first main body portion that covers the opening of the primary heat exchanger and bulges upward; a second extension portion extending outward from a front end and left and right ends of the first main body portion and overlapping a front portion, a left portion, and a right portion of the first extension portion from above; a first crimping piece portion which is a plurality of crimping pieces provided on an outer edge of the second extending portion in order to crimp the first extending portion; an abutment portion extending upward, leftward, and rightward from a rear end of the first main body portion to form an outlet through which the combustion exhaust gas that has passed through the peripheral wall flows out, and abutting against the rear wall of the secondary heat exchanger from behind; The second hood is A second main body portion that covers the outlet and the inlet, bulges rearward, and has a lower end that is narrowed forward; a third extension portion extending outward from upper and lower ends and left and right ends of the second main body portion and overlapping the rear wall and the abutment portion of the housing from the rear; A fourth extension portion that extends rearward from a lower end of the third extension portion and overlaps the entire rear portion of the first extension portion in the left-right direction from above; A method for manufacturing a water heater comprising: a second crimping piece portion which is a plurality of crimping pieces provided on an outer edge of the fourth extension portion in order to crimp the first extension portion; In molding the second hood, When the second hood is attached to the primary heat exchanger and the secondary heat exchanger, a direction corresponding to a front-rear direction is defined as a first direction, and a direction perpendicular to the first direction is defined as a second direction. a first step of applying a force along the first direction to a metal plate to form the second main body portion and the third extension portion, and providing a portion corresponding to the second crimping piece portion in a manner extending from an end portion on one side in the second direction to one side in the first direction; a second step of applying a force along the first direction to a portion of the third extending portion molded in the first step that is continuous with a portion corresponding to the second crimping piece, thereby bending a position of the third extending portion that is spaced a predetermined length from the portion corresponding to the second crimping piece on the other side of the second direction toward the other side of the first direction, to mold the fourth extending portion and the second crimping piece; Equipped with The second crimping piece molded at one end of the second hood in the second direction by the first step and the second step is extended downward, and the second main body is bulged rearward, and the first hood and the second hood are assembled to the primary heat exchanger and the secondary heat exchanger, and the first crimping piece and the second crimping piece are disposed around the entire circumference of the first extension portion. A method for manufacturing a water heater.

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