Casing and water heater

Abstract

A casing (10A) comprises a lower panel (14) disposed below a heavy object, and side panels disposed on the sides of the heavy object, the casing accommodating the heavy object therein. The side panels each have a lower end portion extending from the side of the heavy object to the lower panel (14) and located on the side of the lower panel (14). The lower end portion is not fixed to the lower panel (14), and if subjected to an impact load, is displaced relative to the lower panel (14).

Description

Casing and Water Heater

[0001] The present disclosure relates to a casing and a water heater.

[0002] Some casings house heavy objects, such as a hot water storage tank for storing hot and cold water, and cover the heavy objects. In such a casing, when an impact is applied during operations such as transportation or installation, the casing and the heavy object may move separately, resulting in deformation of the casing, which has a lower strength than the heavy object, due to the impact. In particular, the vertical impact load caused by the heavy object tends to increase, and deformation of the casing is likely to occur due to the impact load. Therefore, casings have been developed to prevent such deformation.

[0003] For example, Patent Document 1 discloses a casing including a side panel disposed on the side of a heavy object, a lower panel disposed under the heavy object, and a bent portion disposed in the vicinity of a fixing portion provided on the lower panel and fixing the lower panel and the side panel. In this casing, the bent portion relieves the stress acting on the fixing portion when an impact is applied. Thereby, deformation of the casing is prevented.

[0004] Japanese Patent Application Laid-Open No. 2012-32106

[0005] In the casing described in Patent Document 1, if the stress generated by an impact exceeds the strength of the side panel, the lower panel, or the bent portion, the casing may be deformed or damaged. Therefore, in order to relieve a greater stress, measures such as increasing the size of the bent portion or increasing the number of bends may be considered. However, there is a risk that the casing itself may become larger or more complex.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to provide a casing and a water heater in which deformation and damage due to impact are prevented and enlargement or complication is suppressed.

[0007] To achieve the above objective, the casing according to this disclosure comprises a lower panel positioned below the heavy object and a side panel positioned to the side of the heavy object, and is a casing for housing the heavy object inside. The side panel extends from the side of the heavy object to the lower panel and has a lower end located to the side of the lower panel, the lower end not being fixed to the lower panel but displacing relative to the lower panel when an impact load is applied.

[0008] According to the configuration of this disclosure, the lower end of the side panel is not fixed to the lower panel and is displaced relative to the lower panel when an impact load is applied. Therefore, deformation and damage due to impact are prevented in the casing. In addition, the side panel has a lower end that extends from the side of the heavy object to the lower panel and is located on the side of the lower panel, and since this lower end is not fixed to the lower panel, the size and complexity of the casing are suppressed.

[0009] A perspective view of the casing of the water heater according to Embodiment 1 of this disclosure, viewed from diagonally above the front. A perspective view of the casing of the water heater according to Embodiment 1, viewed from diagonally below the rear. A front view showing the internal structure of the water heater according to Embodiment 1. A block diagram showing the overall configuration of the water heater according to Embodiment 1. A cross-sectional view of the hot water storage tank and insulation member of the water heater according to Embodiment 1. An enlarged perspective view of the lower part of the hot water storage tank of the water heater according to Embodiment 1. An enlarged cross-sectional view of the lower part of the hot water storage tank of the water heater according to Embodiment 1. A perspective view of the upper part of the hot water storage unit of the water heater according to Embodiment 1 and the frame structure provided in that upper part. A perspective view of the heat exchanger of the heating unit supported by the frame structure of the water heater according to Embodiment 1. An assembly diagram showing the mounting method of the front panel and left side panel of the water heater according to Embodiment 1. An assembly diagram showing the mounting method of the rear panel of the water heater according to Embodiment 1. An enlarged cross-sectional view of the lower part of the right side panel of the water heater according to Embodiment 1. An enlarged cross-sectional view of the lower part of the rear panel of the water heater according to Embodiment 1. Enlarged cross-sectional view of the lower part of the front panel of the water heater according to Embodiment 1 Perspective view of the casing of the water heater according to Embodiment 2 of this disclosure, viewed from the rear at an oblique angle from above Perspective view of the casing of the water heater according to Embodiment 2, viewed from the front at an oblique angle from below Side view showing the state of the water heater when a worker is transporting the water heater according to Embodiment 2 Enlarged cross-sectional view of the boundary between the front panel and the right side panel of the casing of the water heater according to Embodiment 2 Perspective view of the casing of the water heater according to Embodiment 3, viewed from the front at an oblique angle from above Perspective view of the casing of the water heater according to Embodiment 3, viewed from the rear at an oblique angle from below Top view of the casing of the water heater according to Embodiment 3 Enlarged cross-sectional view of the lower part of the right side panel of the water heater according to Embodiment 3 Enlarged cross-sectional view of the lower part of the rear panel of the water heater according to Embodiment 3 Enlarged cross-sectional view of the lower part of the front panel of the water heater according to Embodiment 3 Enlarged top view showing the XXV region shown in Figure 21 Enlarged cross-sectional view of the lower part of a modified example of the right side panel of the water heater according to Embodiment 1 Enlarged cross-sectional view of the lower part of a modified example of the rear panel of the water heater according to Embodiment 1

[0010] Hereinafter, the casing and water heater according to the embodiments of this disclosure will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals. In the Cartesian coordinate system XYZ shown in the drawings, when the cylindrical axis of the cylindrical hot water storage tank of the water heater is oriented vertically, the vertical direction is the Z-axis, and the horizontal plane perpendicular to the vertical direction is the XY plane. Hereafter, this coordinate system will be referenced as appropriate in the explanation.

[0011] (Embodiment 1) The casing according to Embodiment 1 is a casing for housing components of a water heater, which is an example of a heavy object. Hereinafter, the configuration of the casing will be described using as an example a case in which a heating unit equipped with a heating device is arranged on top of a hot water storage unit equipped with a hot water storage tank and an insulating member. First, the overall configuration of the water heater will be described with reference to Figures 1 to 4.

[0012] Figure 1 is a perspective view of the casing 10A of the water heater 1A according to Embodiment 1, viewed from diagonally above the front. Figure 2 is a perspective view of the casing 10A viewed from diagonally below the rear. Figure 3 is a front view showing the internal structure of the water heater 1A. Figure 4 is a block diagram showing the overall configuration of the water heater 1A. Note that Figure 3 shows the casing 10A with the front panel 11, right side panel 12, and left side panel 13 shown in Figures 1 and 2 removed.

[0013] As shown in Figures 1 and 2, the water heater 1A includes a rectangular parallelepiped casing 10A. Also, as shown in Figure 3, the water heater 1A includes a heating unit 20 and a hot water storage unit 50. The heating unit 20 is housed in the upper region of the internal space of the casing 10A, and the hot water storage unit 50 is housed in the lower region of the internal space of the casing 10A.

[0014] The heating unit 20 is a unit having a circuit for heating hot water supplied to heating devices (not shown), such as radiators and floor heating pipes, and hot water stored in the hot water storage unit 50. More specifically, as shown in Figure 4, the heating unit 20 includes a heating circuit 30 that circulates hot water with heating devices (not shown) and a hot water supply circuit 40 that circulates hot water with the hot water storage unit 50.

[0015] The heating circuit 30 includes an expansion tank 31, a multifunction device 32, a pump 33, a heat exchanger 34, a booster heater 35, and a three-way valve 36 for supplying heated water to the heating device. Hereafter, the explanation will assume that the pump 33 is supplying the hot water within the heating circuit 30.

[0016] The expansion tank 31 is a tank that absorbs the expansion of the hot water in the heating circuit 30. When the temperature of the hot water in the heating circuit 30 rises and thermal expansion occurs, the expansion tank 31 temporarily stores the hot water to suppress the pressure rise in the heating circuit 30. The expansion tank 31 is connected to a heating device (not shown) and suppresses the pressure rise of the hot water supplied from that heating device. The expansion tank 31 discharges the hot water supplied from the heating device to the multifunction device 32.

[0017] The multifunction device 32 is a device that has multiple functions. For example, the multifunction device 32 includes a filter that removes scale, such as rust particles, contained in the hot water; a relief valve that releases the hot water to the outside when the pressure of the hot water in the heating circuit 30 exceeds the allowable pressure; and an air vent valve that discharges air accumulated in the heating circuit 30 to prevent a pressure drop in the pump 33. The multifunction device 32 passes the hot water supplied from the expansion tank 31 through these components and then sends it to the pump 33.

[0018] Pump 33 is a device that applies pressure to the hot water in the heating circuit 30 and circulates the hot water between the heating circuit 30 and the heating device. Pump 33 applies pressure to the hot water that has passed through the multifunction device 32 and sends the hot water to the heat exchanger 34.

[0019] The heat exchanger 34 is a device that exchanges heat between the refrigerant heated by the outdoor unit 60 and the hot water flowing through the heating circuit 30. The heat exchanger 34 heats the hot water sent from the pump 33 through heat exchange and discharges it to the booster heater 35.

[0020] The booster heater 35 is an auxiliary device that heats hot water when the heating capacity of the outdoor unit 60 is insufficient. When the booster heater 35 heats the hot water, it discharges the hot water to the three-way valve 36.

[0021] The three-way valve 36 is a device that switches the flow of hot and cold water within the heating circuit 30. The three-way valve 36 switches whether the hot and cold water supplied from the booster heater 35 flows to a heating device (not shown) or to a heat exchanger 41 in the hot water supply circuit 40, which will be described later.

[0022] In the heating circuit 30, the expansion tank 31, multifunction device 32, pump 33, heat exchanger 34, booster heater 35, and three-way valve 36 are connected via piping in this order. The heating circuit 30 receives hot water supplied from the heating device through piping connected to the expansion tank 31, and heats the hot water using the heat exchanger 34 and booster heater 35. When the three-way valve 36 is switched to a state that allows the water to flow to a heating device (not shown), the heating circuit 30 discharges the heated hot water to the heating device. In this way, the heating circuit 30 causes the heating device to use the heated hot water to provide heating.

[0023] On the other hand, when the three-way valve 36 of the heating circuit 30 is switched to a state where it flows to the heat exchanger 41 of the hot water supply circuit 40 (described later), the heated hot water is discharged to the heat exchanger 41 of the hot water supply circuit 40. Next, the configuration of the hot water supply circuit 40 will be explained.

[0024] The hot water supply circuit 40 includes a heat exchanger 41, a scale trap 42, and a pump 43.

[0025] The heat exchanger 41 is a device that exchanges heat between the hot water heated by the heating circuit 30 described above and the hot water in the hot water storage tank 51 of the hot water storage unit 50, which will be described later. More specifically, the heat exchanger 41 is connected to a pipe 44 that extends into the inside of the hot water storage tank 51. The heat exchanger 41 then exchanges heat between the hot water in the hot water storage tank 51 supplied through the pipe and the heated hot water supplied from the heating circuit 30 by switching the three-way valve 36 described above. In this way, the heat exchanger 41 heats the hot water from the hot water storage tank 51. After heating the hot water, the heat exchanger 41 discharges the hot water into the scale trap 42.

[0026] The scale trap 42 is a device that captures scale particles contained in hot water. The scale trap 42 is equipped with an adsorbent, and the heated hot water discharged from the heat exchanger 41 is passed through the adsorbent, thereby capturing scale particles contained in the hot water.

[0027] Pump 43 has a suction port and a discharge port (not shown). A scale trap 42 is connected to the suction port of pump 43 via piping. As a result, pump 43 draws hot water from the scale trap 42. Consequently, pump 43 draws hot water from the hot water storage tank 51 and flows it to the heat exchanger 41 and the scale trap 42.

[0028] Meanwhile, the discharge port of the pump 43 is connected to a pipe 45 that extends into the hot water storage tank 51. As a result, the pump 43 draws hot water from the scale trap 42 and sends it to the hot water storage tank 51. Consequently, the hot water heated by the heat exchanger 41 is sent through the scale trap 42 and the pump 43 to the hot water storage tank 51, i.e., the hot water storage unit 50.

[0029] The hot water storage unit 50 includes a hot water storage tank 51 formed in the shape of a cylinder with convex bulges at both ends. A water supply pipe 52 equipped with a water tap is connected to the hot water storage tank 51, and tap water, i.e., low-temperature water, is supplied from the water supply pipe 52. On the other hand, the pipes 44 and 45 of the hot water supply circuit 40 described above are connected to the hot water storage tank 51, and the water or hot water in the hot water storage tank 51 is converted to hot water at a higher temperature by circulating through the hot water supply circuit 40 via these pipes 44 and 45. Furthermore, a hot water supply pipe 53 equipped with a hot water tap is connected to the hot water storage tank 51. This hot water supply pipe 53 supplies hot water from the hot water storage tank 51 to external equipment.

[0030] Thus, the hot water storage tank 51 stores hot water heated by the hot water supply circuit 40. To keep the hot water warm, the hot water storage unit 50 is equipped with an insulating member that covers the outer surface of the hot water storage tank 51. Next, the configuration of the insulating member will be described in detail with reference to Figures 5-7.

[0031] Figure 5 is a cross-sectional view of the hot water storage tank 51 and the heat insulating member 54 of the hot water heater 1A. Figure 6 is an enlarged perspective view of the lower part of the hot water storage tank 51. Figure 7 is an enlarged cross-sectional view of the lower part of the hot water storage tank 51. Note that hatching has been omitted in Figures 5 and 7.

[0032] The thermal insulation member 54 is made of foamed plastic, such as expanded polystyrene. The thermal insulation member 54 is formed by combining the thermal insulation materials of the top surface 541, right side surface 542, left side surface 543, and bottom surface 544 shown in Figure 5, which are made of the same material.

[0033] The top surface 541 is formed in the shape of an inverted bowl. The shape of the upper surface of the top surface 541 will be described later, but the lower surface of the top surface 541 is concave in a parabolic shape. As a result, the top surface 541 fits onto the upper surface of the hot water storage tank 51. In addition, the top surface 541 covers the upper surface of the hot water storage tank 51, suppressing heat dissipation from the upper surface of the hot water storage tank 51.

[0034] Furthermore, the right side portion 542 and the left side portion 543 are formed in a semi-cylindrical shape. The right side portion 542 and the left side portion 543 are fitted into the right and left walls of the hot water storage tank 51, respectively. As a result, the right side portion 542 and the left side portion 543 cover the outer circumferential surface of the hot water storage tank 51. Consequently, the right side portion 542 and the left side portion 543 suppress heat dissipation from the outer circumferential surface of the hot water storage tank 51.

[0035] The hot water storage tank 51 has a parabolic projection at its bottom, and a cylindrical base 511 is welded to this bottom portion. The bottom portion 544 of the heat insulating member 54 is formed in the shape of a bowl with a cylindrical cutout in the center, so that it fits into the bottom of the hot water storage tank 51 and the base 511.

[0036] Furthermore, as shown in Figures 6 and 7, L-shaped brackets 512 are connected to the base 511 by bolts 513 and nuts 514 for fixing to the lower panel 14 of the casing 10A. These L-shaped brackets 512 are then fixed to the lower panel 14 by bolts 515 and nuts 516, with a cushioning material 517 sandwiched between them. Three such L-shaped brackets 512 are provided on the outer circumference of the base 511.

[0037] The bottom portion 544 of the heat insulating member 54 has through holes 545 formed on its side to prevent interference with the L-shaped bracket 512. Although not shown in the figure, the through holes 545 are also formed in three locations on the side of the bottom portion 544. The bottom portion 544 has this configuration and covers the bottom surface of the hot water storage tank 51. As a result, the bottom portion 544 suppresses heat dissipation from the bottom surface of the hot water storage tank 51.

[0038] Returning to Figure 3, the hot water storage unit 50, which is equipped with such an insulating member 54, is provided with a frame structure that supports the components of the heating unit 20. Next, the frame structure will be described with reference to Figures 8 and 9.

[0039] Figure 8 is a perspective view of the upper part of the hot water storage unit 50 of the hot water heater 1A and the frame structure 70 provided on that upper part. Figure 9 is a perspective view of the heat exchangers 34 and 41 of the heating unit 20 supported by the frame structure 70. In Figure 9, for ease of understanding, only the heat exchangers 34 and 41 are shown, and the heating unit 20 is shown with the top surface 541 of the heat insulating member 54 resting on it.

[0040] As shown in Figure 8, the frame structure 70 is formed in the shape of a rectangular parallelepiped frame that is installed on the top surface 541 of the heat insulating member 54.

[0041] In detail, the top surface 541 is rectangular in shape when viewed from above. The top surface 541 has each side of its rectangular shape oriented in the left-right direction and the front-back direction, i.e., the X direction and Y direction. The frame structure 70 has a U-shaped lower frame section 71 arranged along the +X, -X, and -Y sides of its rectangular shape, a rectangular frame-shaped upper frame section 72 provided on top of the lower frame section 71, i.e., on the +Z side, support columns 73-76 connecting the upper frame section 72 to the lower frame section 71, and a beam section 77 provided between the support columns 74 and 75.

[0042] The lower frame portion 71 is formed by connecting three elongated steel plates having an L-shaped cross section, that is, three angle steels called angles. Specifically, the lower frame portion 71 is formed by combining three angle steels having the same length as each side of the rectangle, which is the top surface view shape of the heat insulating member 54, in a U shape. And each angle steel has the inner corner portion of the L-shaped cross section facing the corner portion formed by the +Z plane and the +X plane, -Y plane or -X plane of the top surface portion 541, and covering the corner portion respectively. And each angle steel is placed on the top surface portion 541 in that state. Thereby, the lower frame portion 71 is supported by the top surface portion 541.

[0043] On the other hand, the upper frame portion 72 is formed by combining a steel material having the same length as the +Y side and -Y side of the rectangle, which is the top surface view shape of the heat insulating member 54, and a steel material shorter than the +X side and -X side of the rectangle in the top surface view shape of the heat insulating member 54. Here, the steel material means the above-mentioned angle steel or the groove steel having a U-shaped cross section. The upper frame portion 72 is formed by combining such steel materials to form a rectangular frame.

[0044] The support portions 73 - 76 are formed by steel materials extending the same length in the +Z direction from the lower frame portion 71. And the support portions 73 - 76 support each corner portion of the rectangular frame having the shape of the upper frame portion 72. On the other hand, between the support portions 74 and 75, a beam portion 77 is provided to support the heat exchangers 34 and 41 of the heating unit 20.

[0045] The beam portion 77 is formed of the above-mentioned steel materials, for example, angle steel or groove steel. The length in its extending direction is the same as the distance from the support portion 74 to the support portion 75. And the beam portion 77 is fitted between the support portions 74 and 75 with its extending direction being horizontal. Its position in the Z direction is lower than the +Z ends of the heat exchangers 34 and 41 in the state where the heat exchangers 34 and 41 of the heating unit 20 are assembled to the top surface portion 541 shown in FIG. 9. Thereby, the beam portion 77 crosses the middle portion of the heat exchangers 34 and 41 in the Y direction view.

[0046] Also, as shown in FIG. 8, both ends of the beam portion 77 are fixed to the column portions 74 and 75, respectively, at the positions described above. As a result, the beam portion 77 is supported by the lower frame portion 71 via the column portions 74 and 75.

[0047] In the frame structure 70 having such a configuration, as shown in FIG. 9, metal fittings 771 - 773 for holding the heat exchangers 34 and 41 of the heating unit 20 are fixed in a state where the heating unit 20 is assembled to the top surface portion 541 of the heat insulating member 54.

[0048] Specifically, the metal fitting 771 is formed by bending a strip-shaped metal plate into a U shape. Then, the heat exchanger 34 is fitted inside the U shape of the metal fitting 771, thereby holding the heat exchanger 34. Further, one end of the strip of the metal fitting 771 is fixed to the beam portion 77, and the other end of the strip of the metal fitting 771 is fixed to the column portion 75. As a result, the beam portion 77 and the column portion 75 support the heat exchanger 34 via the metal fitting 771.

[0049] Also, the metal fitting 772 is formed by bending a strip-shaped metal plate into an L shape. Then, the metal fitting 772 covers the corner portion of the outer shape of the heat exchanger 34 at the inner corner portion of the L shape, and is fixed to the column portion 75 and the upper frame portion 72 in a state where the plate surface of the L shape is abutted against the -Y plane and the -X plane of the heat exchanger 34. As a result, the column portion 75 and the upper frame portion 72 support the heat exchanger 34 via the metal fitting 772.

[0050] Further, although not shown, the metal fitting 773 is formed in the same manner as the metal fitting 771 by bending a strip-shaped metal plate into a U shape. Then, the heat exchanger 41 is fitted inside the U shape of the metal fitting 773, thereby holding the heat exchanger 41. Further, one end of the strip of the metal fitting 773 is fixed to the beam portion 77, and the other end of the strip of the metal fitting 773 is fixed to the column portion 74. As a result, the beam portion 77 and the column portion 74 support the heat exchanger 41 via the metal fitting 773.

[0051] Returning to Figures 1 and 2, the heating unit 20 and hot water storage unit 50 with this configuration are housed within the casing 10A. More specifically, the casing 10A comprises a front panel 11, a right-side panel 12, a left-side panel 13, a lower panel 14, a rear panel 15, and an upper panel 16, all of which are formed in a plate shape. The heating unit 20 and the hot water storage unit 50 are housed in the internal space enclosed by these panels.

[0052] However, in the water heater 1A, the heating unit 20 has many parts, and these parts of the heating unit 20 are supported by the frame structure 70. In addition, the hot water storage unit 50 has a large hot water storage tank 51. As a result, the heating unit 20 and the hot water storage unit 50 are heavier than the casing 10A, and are so-called heavy objects. Here, a heavy object refers to something that is heavy, for example, something that is heavier than each panel of the casing 10A. As a result, if the water heater 1A is subjected to impact during work such as transportation or installation, the casing 10A, the heating unit 20, and the hot water storage unit 50 may move separately, and the casing 10A, which is weaker than the heating unit 20 and the hot water storage unit 50, may deform. The impact load applied to the water heater 1A tends to be particularly large in the vertical direction, i.e., in the Z direction, and such an impact load is likely to cause deformation of the casing 10A.

[0053] Therefore, in casing 10A, the front panel 11, right side panel 12, left side panel 13, and rear panel 15 are not fixed to the lower panel 14, and are displaced relative to the lower panel 14 when an impact load is applied. Next, with reference to Figures 10-14, the mounting structure of the front panel 11, right side panel 12, left side panel 13, lower panel 14, and rear panel 15 of casing 10A to the heating unit 20 and the hot water storage unit 50 will be described.

[0054] Figure 10 is an assembly diagram showing the mounting method for the front panel 11 and the left side panel 13. Figure 11 is an assembly diagram showing the mounting method for the rear panel 15. Figures 12-14 are enlarged cross-sectional views of the lower parts of the right side panel 12, the rear panel 15, and the front panel 11, respectively.

[0055] As shown in Figure 10, the front panel 11 is fixed to the upper surface of the frame structure 70 by multiple screws 90. The left side panel 13 is fixed to the upper surface and left side of the frame structure 70 by multiple screws 90. Although not shown, the right side panel 12 is also fixed to the upper surface and right side of the frame structure 70 by multiple screws 90. Furthermore, as shown in Figure 11, the rear panel 15 is fixed to the back surface of the frame structure 70 and the right side panel 12 by multiple screws 90. Although not shown, the rear panel 15 is also fixed to the left side panel 13 by multiple screws 90. In this way, the front panel 11, the right side panel 12, the left side panel 13, and the rear panel 15 are fixed to the frame structure 70.

[0056] In contrast, the lower panel 14 is fixed to a base 511 provided on the hot water storage tank 51 by bolts 513 and nuts 514, as explained with reference to Figures 6 and 7. The front panel 11, right side panel 12, left side panel 13, and rear panel 15, having the structure described above, are not fixed to the lower panel 14, but are displaceable relative to the lower panel 14, and form the casing 10A while maintaining this displaceable state. As a result, even if the heavy hot water storage tank 51 moves due to impacts during work such as transportation or installation, the lower panel 14 will displace relative to the front panel 11, right side panel 12, left side panel 13, and rear panel 15, and will not affect the positions of those panels.

[0057] Furthermore, the front panel 11, right side panel 12, left side panel 13, and rear panel 15 are not fixed to the lower panel 14, so even if the heavy heating unit 20, which is supported by the frame structure 70, moves due to an impact during operation and moves together with the frame structure 70, the front panel 11, right side panel 12, left side panel 13, and rear panel 15 can be displaced relative to the lower panel 14. As a result, the movement of the heating unit 20 and the frame structure 70 due to impact does not affect the lower panel 14.

[0058] Thus, the front panel 11, right side panel 12, left side panel 13, and rear panel 15 are displaceable relative to the lower panel 14 when an impact is applied. However, if the front panel 11, right side panel 12, left side panel 13, and rear panel 15 are freely displaced relative to the lower panel 14, the function of the casing 10A will be impaired. Therefore, the front panel 11, right side panel 12, left side panel 13, and rear panel 15 are provided with a structure that allows them to be displaced within a certain range relative to the lower panel 14 when displaced by an impact.

[0059] More specifically, as shown in Figure 12, the lower end portion of the right-side panel 12 is bent in a cross-sectional view in the shape of a sideways Z. More specifically, the lower end portion of the right-side panel 12 has a first bent portion 121 that extends downward and then bends sharply to the left and inward, a second bent portion 122 that extends upward to the left and inward from the first bent portion 121 and then bends downward, and a lowest end portion 123 that extends downward from the second bent portion 122, specifically parallel to the direction in which the flat panel surface 127 of the right-side panel 12 extends.

[0060] In contrast, the lower panel 14 has an upright wall 141 on its outer edge, specifically on its right edge. Figure 12 shows only the right edge of the lower panel 14, but the upright wall 141 is also provided on the left edge, front edge, and rear edge of the lower panel 14, and as a result surrounds the outer periphery of the lower panel 14.

[0061] The lowest end portion 123 of the right-side panel 12 extends downward until it is located to the left of the upright wall 141. Furthermore, the lowest end portion 123 is located inside the hot water storage unit 50, relative to the upright wall 141. In detail, the lowest end portion 123 is inserted into the gap G1 between the upright wall 141 and the bottom portion 544 of the insulation member 54. Since the lowest end portion 123 is not fixed to the upright wall 141, if the heating unit 20 moves due to an impact, the impact load will not be transmitted to the upright wall 141. Similarly, if the hot water storage tank 51 moves due to an impact, the impact load will not be transmitted from the upright wall 141. The lowest end portion 123 is also capable of displacing from the upright wall 141 in the left-right direction by the size of the gap G1.

[0062] Furthermore, the lowest portion 123 is inserted into the gap G1 between the upright wall 141 and the bottom portion 544 of the insulation member 54, so that it faces the upright wall 141 on the inside. As a result, the lowest portion 123 prevents the right side panel 12 from moving outward beyond the upright wall 141 when the heating unit 20 or the hot water storage tank 51 moves due to an impact and the right side panel 12 is displaced relative to the lower panel 14. This prevents the right side panel 12 from coming off the lower panel 14. It also prevents deformation and breakage of the right side panel 12.

[0063] Furthermore, the second bend 122 of the right-side panel 12 has its lowest end portion 123 bent in a hook shape relative to the extended portion 124 that extends from the first bend 121 to the second bend 122 in cross-sectional view. This extended portion 124 is located a distance D1 above the upright wall 141. In addition, the lowest end portion 123 of the right-side panel 12 extends downward to a position where it overlaps with the upright wall 141. With this configuration, the lowest end portion 123 of the right-side panel 12 can be displaced relative to the upright wall 141 by a distance D1 in the vertical direction if the heating unit 20 or the hot water storage tank 51 is moved by an impact.

[0064] Furthermore, the second bent portion 122 of the right-side panel 12 is bent in a hook shape at its lowest end portion 123 relative to the extended portion 124 in cross-sectional view, so that the hook-shaped portion of the right-side panel 12 in cross-sectional view can be hooked onto the upright wall 141. As a result, even if the heating unit 20 or the hot water storage tank 51 moves due to impact and the right-side panel 12 is displaced in the left-right or up-down direction relative to the lower panel 14, the right-side panel 12 is less likely to detach from the lower panel 14.

[0065] Furthermore, the second bend 122 of the right-side panel 12 is located above the first bend 121. This makes the part where the lowest end portion 123 of the right-side panel 12 is inserted less visible, thereby enhancing the design aesthetics.

[0066] Thus, the right-side panel 12 is displaceable relative to the lower panel 14, and is prevented from detaching from the lower panel 14 and displacing outward when the lower panel 14 is displaced, or when the right-side panel 12 is displaced relative to the lower panel 14. Furthermore, the right-side panel 12 is protected from deformation and destruction of itself.

[0067] Although not shown in the diagram, the left-side panel 13 is formed symmetrically with the right-side panel 12. As a result, the left-side panel 13 has the same configuration as the right-side panel 12. Therefore, although a detailed explanation is omitted, the left-side panel 13, like the right-side panel 12, is displaceable relative to the lower panel 14, and is prevented from detaching from the lower panel 14 and displacing outward when the lower panel 14 is displaced, or when the left-side panel 13 is displaced relative to the lower panel 14. In addition, the left-side panel 13 is protected from deformation and breakage of its own.

[0068] As shown in Figure 13, the lower end portion of the rear panel 15 is bent in a crank shape in cross-section. More specifically, the lower end portion of the rear panel 15 has a first bent portion 151 that extends downward and then bends forward and inward at a right angle, a second bent portion 152 that extends forward and inward from the first bent portion 151 and then bends downward at a right angle, and the lowest end portion 153 that extends downward from the second bent portion 152.

[0069] The first bent portion 151 and the second bent portion 152 of the rear panel 15 are located a distance D2 above the upright wall 141. The lowest end portion 153 of the rear panel 15 extends downward to a position in front of the upright wall 141, similar to the lowest end portion 123 of the right side panel 12, and is further inserted into the gap G2 between the upright wall 141 and the bottom surface portion 544 of the heat insulating member 54, so that it is located inside the upright wall 141. As a result of this configuration, the lowest end portion 153 of the rear panel 15, similar to the lowest end portion 123 of the right side panel 12, can be displaced vertically by a distance D2 relative to the upright wall 141 if the heating unit 20 or the hot water storage tank 51 is moved by an impact. It can also be displaced longitudinally relative to the upright wall 141 by the size of the gap G2.

[0070] Furthermore, as a result of this configuration, the lowest portion 153 of the rear panel 15, similar to the lowest portion 123 of the right side panel 12, prevents the rear panel 15 from detaching from the lower panel 14 if the heating unit 20 or the hot water storage tank 51 moves due to impact and the rear panel 15 is displaced relative to the lower panel 14 in the front-to-back or up-to-down direction. In addition, the rear panel 15 itself is protected from deformation and breakage.

[0071] Furthermore, as shown in Figure 14, the lower end portion of the front panel 11 is bent in an L-shape in cross-section. More specifically, the lower end portion of the front panel 11 has a first bent portion 111 that extends downward and then bends at a right angle to the rear and inward, and a lowest end portion 113 that extends rear and inward from the first bent portion 111. The lowest end portion 113 extends in a direction perpendicular to the wall surface of the upright wall 141, and the end face of the lowest end portion 113 faces the upright wall 141. The end face of the lowest end portion 113 is located outside and away from the upright wall 141. Therefore, if the heating unit 20 or the hot water storage tank 51 is moved by an impact, the lowest end portion 113 of the front panel 11 can be displaced relative to the upright wall 141 in the vertical or front-to-back direction. In this way, the lowest end portion 113 prevents the front panel 11 from being destroyed.

[0072] As described above, the lowest portions 113, 123, and 153 of the front panel 11, right side panel 12, left side panel 13, and rear panel 15 of the casing 10A are not fixed to the lower panel 14 and are displaced relative to the lower panel 14 when an impact load is applied. Therefore, the casing 10A can be prevented from deforming and breaking due to impact.

[0073] Furthermore, the front panel 11 and the rear panel 15 extend to the upright wall 141 of the lower panel 14 and have their lowest end portions 113 and 153 located to the sides of the upright wall 141, i.e., in the front-rear direction. Similarly, the right side panel 12 and the left side panel 13 extend to the upright wall 141 of the lower panel 14 and have their lowest end portions 123 located to the sides of the upright wall 141, i.e., in the left-right direction. These lowest end portions 113, 123, and 153 are simply not fixed to the lower panel 14. As a result, the size and complexity of the casing 10A are suppressed.

[0074] The right-side panel 12, the left-side panel 13, and the rear panel 15 each have their lowest end portions 123 and 153 that are inserted inward from the upright wall 141 of the lower panel 14. Therefore, the right-side panel 12, the left-side panel 13, and the rear panel 15 are less likely to be displaced outward and detached from the lower panel 14. As a result, the right-side panel 12, the left-side panel 13, and the rear panel 15 can prevent deformation and damage to the casing 10A due to impact.

[0075] The lower end portion of the right-side panel 12 has a first bent portion 121 that extends downward and then bends laterally and inward, a second bent portion 122 that extends laterally and inward from the first bent portion 121 and then bends downward, and a lowest end portion 123 that extends downward from the second bent portion 122. The lowest end portion 123 extends inward beyond the upright wall 141 of the lower panel 14 and faces the upright wall 141. Therefore, the lower end portion of the right-side panel 12 is displaceable relative to the lower panel 14 when an impact load is applied. In addition, the lower end portion of the right-side panel 12 is less likely to detach from the upright wall 141, which prevents deformation and damage to the casing 10A due to impact.

[0076] The lower end portion of the left panel 13 has the same configuration as the lower end portion of the right panel 12. As a result, the lower end portion of the left panel 13 can also be displaced relative to the lower panel 14 when an impact load is applied, and deformation and damage to the casing 10A due to impact can be prevented.

[0077] Furthermore, the lower end portion of the rear panel 15 has the same configuration as the lower end portion of the right side panel 12. Specifically, the lower end portion of the rear panel 15 has a first bent portion 151 that extends downward and then bends forward and inward, a second bent portion 152 that extends forward and inward from the first bent portion 121 and then bends downward, and a lowest end portion 153 that extends downward from the second bent portion 152. The lowest end portion 153 extends inward beyond the upright wall 141 of the lower panel 14 and faces the upright wall 141. Therefore, the lower end portion of the rear panel 15, like the lower end portion of the right side panel 12, can be displaced relative to the lower panel 14 when an impact load is applied, and deformation and damage to the casing 10A due to impact can be prevented.

[0078] The front panel 11, right side panel 12, left side panel 13, and rear panel 15 described in Embodiment 1 are examples of side panels as defined in this disclosure. Also, the lowest end portion 113 of the front panel 11, the lowest end portion 123 of the right side panel 12, and the lowest end portion 153 of the rear panel 15 are examples of the lower end portions of side panels as defined in this disclosure.

[0079] (Embodiment 2) In order to ensure that the casing 10A has sufficient rigidity to withstand rotational force when a rotational force is applied to the heating unit 20 or the hot water storage tank 51, the side panels, i.e., the front panel 11, the right side panel 12, the left side panel 13, and the rear panel 15, may have contact portions that come into contact with the heating unit 20 or the hot water storage unit 50 to suppress deformation.

[0080] The casing 10B according to Embodiment 2 has a contact portion at the boundary between the front panel 11 and the right-side panel 12.

[0081] The casing 10B according to Embodiment 2 will be described below with reference to Figures 15-18. Embodiment 2 will be described primarily for its configuration, which differs from that of Embodiment 1.

[0082] Figure 15 is a perspective view of the casing 10B of the water heater 1B according to Embodiment 2, viewed from the rear at an oblique angle from above. Figure 16 is a perspective view of the casing 10B, viewed from the front at an oblique angle from below. Figure 17 is a side view showing the water heater 1B being transported by worker 2. Figure 18 is an enlarged cross-sectional view of the boundary between the front panel 11 and the right side panel 12 of the casing 10B.

[0083] The water heater 1B is large and heavy because it is equipped with a hot water storage tank 51. Furthermore, it is common for the worker 2 to transport the water heater 1B to the installation site. Therefore, to facilitate the transport of the water heater 1B, as shown in Figure 15, the rear panel 15 of the casing 10B is provided with two handle portions 17, arranged horizontally and recessed to allow the worker 2's hands to enter. These handle portions 17 are made by plastic molding and are located on the upper part of the rear panel 15.

[0084] Furthermore, as shown in Figure 16, the front panel 11 of the casing 10B is provided with a handle portion 18 having a shape formed by bending a long, narrow strip of metal into a U-shape. This handle portion 18 is manufactured by sheet metal processing and is located at the bottom of the front panel 11.

[0085] In the water heater 1B, in order to support the gravitational force G acting on the center of gravity CG, as shown in Figure 17, one worker 2 holds the handle 17 and another worker 2 holds the handle 18. The water heater 1B is transported by this means. At this time, a rotational force F1 acts on the handle 17 held by the worker 2 who is in front of the center of gravity CG D3 of the water heater 1B, around the axis from the right side panel 12 to the left side panel 13, that is, around the left-right axis. Also, a rotational force F2 acts on the handle 18 held by the worker 2 who is behind the center of gravity CG D4 of the water heater 1B, around the left-right axis. Here, since the rotational forces F1 and F2 are forces that rotate around the left-right axis, they act as rotational forces in the direction from the upper panel 16 to the lower panel 14 of the casing 10B, or in the opposite direction. As a result of these rotational forces F1 and F2 acting on it, the casing 10B may deform in the direction of the rotational forces F1 and F2.

[0086] Therefore, in order to increase the rigidity of the casing 10B, the end of the front panel 11 is bent into an L-shape, as shown in Figure 18. More specifically, the front panel 11 has a bent portion 115 parallel to the XZ plane, by bending the end of the plate surface parallel to the YZ plane at a right angle.

[0087] Furthermore, the end of the right-side panel 12 is bent in a crank shape, and this bent portion is superimposed on the bent portion 115 of the front panel 11. More specifically, the end of the plate surface of the right-side panel 12 parallel to the YZ plane is first bent parallel to the XZ plane, and then bent parallel to the YZ plane again. As a result, the right-side panel 12 has a first bent portion 125 parallel to the XZ plane and a second bent portion 126 parallel to the YZ plane, which is located closer to the front panel 11 than the first bent portion 125. The first bent portion 125 is then superimposed on the bent portion 115 of the front panel 11.

[0088] In contrast, the heat insulating member 54 has a recess 546 formed in the shape of a groove that is L-shaped in cross-section and extends in the vertical direction. More specifically, the recess 546 is formed in a shape that combines a wall portion 547 that is parallel to the XZ plane and extends in the Z direction and a wall portion 548 that is parallel to the YZ plane and extends in the Z direction.

[0089] The portion where the bent portion 115 of the front panel 11 and the first bent portion 125 of the right side panel 12 meet faces the wall portion 547 of the recess 546 of the heat insulating member 54. As a result, when the rotational forces F1 and F2 during transport, as explained with reference to Figure 17, act on the water heater 1B, the portion where the bent portion 115 of the front panel 11 and the first bent portion 125 of the right side panel 12 meet comes into contact with the wall portion 547 of the recess 546 of the heat insulating member 54. This causes the portion where the bent portion 115 of the front panel 11 and the first bent portion 125 of the right side panel 12 meet supports the heat insulating member 54, increasing the rigidity of the water heater 1B itself and the casing 10B. This suppresses deformation of the water heater 1B and the casing 10B.

[0090] Furthermore, the second bent portion 126 of the right-side panel 12 faces the wall portion 548 of the recess 546 of the heat insulating member 54. As a result, when a force is applied in the left-right direction during the transport of the water heater 1B, the second bent portion 126 of the right-side panel 12 comes into contact with the wall portion 548 of the recess 546 of the heat insulating member 54. This causes the second bent portion 126 of the right-side panel 12 to support the wall portion 548 of the recess 546 of the heat insulating member 54, thereby increasing the rigidity of the water heater 1B itself and the casing 10B. This suppresses deformation of the water heater 1B and the casing 10B.

[0091] Furthermore, the bent portion 115 of the front panel 11 and the first bent portion 125 of the right side panel 12 described in Embodiment 2 are examples of flat surfaces that come into contact with a heavy object when a rotational force in the vertical direction is applied to the heavy object, causing the heavy object to be displaced relative to the side panel. In addition, although the rotational forces F1 and F2 were described as rotational forces in the direction from the upper panel 16 of the casing 10B toward the lower panel 14, or vice versa, the rotational forces F1 and F2 are examples of rotational forces in the vertical direction as described in this disclosure.

[0092] As described above, in the casing 10B of the water heater 1B according to Embodiment 1, the front panel 11 has a bent portion 115 formed on the inner wall surface and parallel to the XZ plane. That is, the front panel 11 has a bent portion 115 that extends in the left-right and up-down directions. When rotational forces F1 and F2 are applied around the left-right axis, the bent portion 115 comes into contact with the wall portion 548 of the recess 546 of the heat insulating member 54. In other words, the bent portion 115 functions as a contact portion that comes into contact with the heavy hot water storage unit 50. By coming into contact with the hot water storage unit 50, the bent portion 115 increases the rigidity of the casing 10B including the front panel 11 and suppresses deformation of the casing 10B.

[0093] Furthermore, the right-side panel 12 has a first bent portion 125 formed on its inner wall surface and parallel to the XZ plane. This first bent portion 125 contacts the wall portion 548 of the recess 546 of the heat insulating member 54 when rotational forces F1 and F2 are applied around the left-right axis. In other words, the first bent portion 125 functions as a contact portion that contacts the heavy hot water storage unit 50. Similar to the bent portion 115 of the front panel 11, the first bent portion 125 contacts the hot water storage unit 50, thereby increasing the rigidity of the casing 10B and suppressing deformation of the casing 10B.

[0094] (Embodiment 3) In embodiments 1 and 2, the lowest portions 123 and 153 of the right side panel 12, left side panel 13, and rear panel 15 of the casing 10A are located inside the upright wall 141 of the lower panel 14. However, the right side panel 12, left side panel 13, and rear panel 15 are not limited to these. The right side panel 12, left side panel 13, and rear panel 15, i.e., the side panels, have lower ends that extend from the side of the heavy object to the lower panel 14 and are located on the side of the lower panel 14, and these lower ends are not fixed to the lower panel 14 but are displaced relative to the lower panel 14 when an impact load is applied. Therefore, it is optional whether or not the lowest portions 123 and 153 of the right side panel 12, left side panel 13, and rear panel 15 are inside the upright wall 141 of the lower panel 14.

[0095] In the casing 10C of the water heater 1C according to Embodiment 3, the lowest portions 123 and 153 of the right side panel 12, the left side panel 13, and the rear panel 15 are located outside the upright wall 141 of the lower panel 14. Also, the lower end portion of the front panel 11 is located outside the upright wall 141 of the lower panel 14.

[0096] The casing 10C according to Embodiment 3 will be described below with reference to Figures 19-25. Embodiment 3 will be described primarily for its configuration, which differs from that of Embodiments 1 and 2.

[0097] Figure 19 is a perspective view of the casing 10C of the water heater 1C according to Embodiment 3, viewed from diagonally above the front. Figure 20 is a perspective view of the casing 10C viewed from diagonally below the rear. Figure 21 is a top view of the casing 10C.

[0098] As shown in Figures 19-21, the casing 10C is formed in a rectangular parallelepiped shape, similar to the casings 10A and 10B of Embodiments 1 and 2. Furthermore, the casing 10C, similar to the casing 10B of Embodiment 2, has two handle portions 17 at the upper end of the rear panel 15, as shown in Figure 20. In addition, unlike the casing 10B of Embodiment 2, the casing 10C has two handle portions 19 at the front of the lower panel 14, which are recessed inward from the lower panel 14 and into which the hands of the operator 2 can be inserted.

[0099] Even with a casing 10C of this shape, as with embodiments 1 and 2, it is necessary to prevent deformation and damage when an impact load is applied. Therefore, in casing 10C, the lowest portions 113, 123, and 153 of the front panel 11, right side panel 12, left side panel 13, and rear panel 15 are not fixed to the lower panel 14. Furthermore, the lowest portions 113, 123, and 153 of the front panel 11, right side panel 12, left side panel 13, and rear panel 15 are located outside the upright wall 141 of the lower panel 14. The configurations of the right side panel 12, left side panel 13, and rear panel 15 will be described in detail with reference to Figures 22-24.

[0100] Figure 22 is an enlarged cross-sectional view of the lower part of the right-side panel 12 of the water heater 1C according to Embodiment 3. Figure 23 is an enlarged cross-sectional view of the lower part of the rear panel 15 of the water heater 1C. Figure 24 is an enlarged cross-sectional view of the lower part of the front panel 11 of the water heater 1C.

[0101] As shown in Figure 22, the upright wall 141 of the lower panel 14 extends straight upward in a cross-sectional view. In contrast, the lowest end portion 123 of the right side panel 12 extends straight downward in a cross-sectional view. The lowest end portion 123 of the right side panel 12 is located to the right of the upright wall 141 of the lower panel 14 and overlaps the upright wall 141 from the right. That is, the lowest end portion 123 of the right side panel 12 is in contact with the upright wall 141 from the outside. And, as in the first embodiment, the lowest end portion 123 of the right side panel 12 is not fixed to the upright wall 141, but is only in contact with it.

[0102] The lowest end portion 123 of the right-side panel 12, with this configuration, can be displaced relative to the lower panel 14 in the vertical direction when a force acts on the right-side panel 12 that displaces it relative to the lower panel 14 as a result of the heating unit 20 or the hot water storage tank 51 moving due to an impact. Furthermore, since the lowest end portion 123 of the right-side panel 12 is in contact with the upright wall 141 of the lower panel 14 from the outside, it is prevented from detaching from the lower panel 14 even if it is displaced relative to the lower panel 14 in the vertical direction. As a result, deformation or breakage of the right-side panel 12 due to impact load is suppressed.

[0103] Although not shown in the diagram, the left-side panel 13 is formed symmetrically with the right-side panel 12. As a result, the left-side panel 13 has the same configuration as the right-side panel 12. Therefore, although a detailed explanation is omitted, the left-side panel 13, like the right-side panel 12, can be displaced relative to the lower panel 14 in the vertical direction even when a force acts on the left-side panel 13 that displaces it relative to the lower panel 14 due to an impact from the heating unit 20 or the hot water storage tank 51. In addition, the lowest part of the left-side panel 13 is in contact with the upright wall 141 of the lower panel 14 from the outside, so even if it is displaced relative to the lower panel 14 in the vertical direction, it is prevented from coming off the lower panel 14. As a result, deformation or breakage of the left-side panel 13 due to impact loads is suppressed.

[0104] As shown in Figure 23, even at the lower rear of the casing 10C, the upright wall 141 of the lower panel 14 extends straight upward in cross-sectional view. In contrast, the lower end portion of the rear panel 15 is bent in a crank shape in cross-sectional view, similar to Embodiment 1. As a result, the lower end portion of the rear panel 15 has, similar to Embodiment 1, a first bent portion 151 that extends downward and then bends forward and inward at a right angle, a second bent portion 152 that extends forward and inward from the first bent portion 151 and then bends downward at a right angle, and a lowest end portion 153 that extends downward from the second bent portion 152. In this lower end portion of the rear panel 15, unlike in Embodiment 1, the lowest end portion 153 is located outside the upright wall 141 of the lower panel 14 and is in contact with the upright wall 141 from the outside. Furthermore, the lowest portion 153 is not fixed to the upright wall 141, but merely touches it, similar to the first embodiment.

[0105] The lowest end portion 153 of the rear panel 15, having this configuration, can be displaced relatively vertically with respect to the lower panel 14 even when a force that displaces the rear panel 15 relative to the lower panel 14 is applied due to an impact from the heating unit 20 or the hot water storage tank 51, similar to the case of the right side panel 12 and left side panel 13 described above. Furthermore, since the lowest end portion 153 of the rear panel 15 is in contact with the upright wall 141 of the lower panel 14 from the outside, it is prevented from detaching from the lower panel 14 even if it is displaced relatively vertically with respect to the lower panel 14. Specifically, the lowest end portion 153 of the rear panel 15 is prevented from detaching from the lower panel 14 even though the panel surface 157 of the rear panel 15 is at a distance D5 from the upright wall 141 of the lower panel 14 as a result of the rear panel 15 bending in a crank shape. As a result, deformation or breakage of the rear panel 15 due to impact load is suppressed.

[0106] Furthermore, as shown in Figure 24, at the front lower part of the casing 10C, the upright wall 141 of the lower panel 14 extends straight upward in cross-sectional view. In contrast, the lower end portion of the front panel 11 is bent into a U-shape with a pointed corner in cross-sectional view. As a result, the lower end portion of the front panel 11 has a first bend 111 that extends downward and then bends at a right angle to the rear and inward, a second bend 112 that extends rearward and inward from the first bend 111 and then bends at a right angle upward, and a folded-back portion 114 that extends upward from the second bend 112. The folded-back portion 114 extends parallel to the upright wall 141 of the lower panel 14 and faces the upright wall 141 from the front, i.e., from the outside. Furthermore, the folded-back portion 114 is positioned at a distance D6 from the upright wall 141.

[0107] The lower end portion of the front panel 11, with this configuration, can, similar to the right side panel 12, left side panel 13, and rear panel 15 described above, be displaced relative to the lower panel 14 by a force acting on it that displaces the front panel 11 relative to the lower panel 14 due to impact from the heating unit 20 or the hot water storage tank 51. This displacement is limited to vertical movement relative to the lower panel 14, or forward movement by a distance D6. Furthermore, at the lower end portion of the front panel 11, the folded portion 114 extends upward and faces the upright wall 141 of the lower panel 14, preventing it from detaching from the lower panel 14 even when displaced relative to it. As a result, deformation and breakage of the front panel 11 due to impact loads are suppressed. Moreover, since the lower end portion of the front panel 11 is bent into a U-shape in cross-section, the upright wall 141 of the lower panel 14 is less likely to be damaged even when displaced relative to it. Furthermore, the lower end portion of the front panel 11 provides stability when placed on the floor during work, and also improves workability when assembling the casing 10C.

[0108] The right-side panel 12 and the left-side panel 13 are fixed to the rear panel 15. Figure 25 shows the connection between the right-side panel 12 and the rear panel 15. Figure 25 is an enlarged top view showing the XXV region shown in Figure 21.

[0109] As shown in Figure 25, the rear end of the right-side panel 12 is fixed to the rear panel 15 by a screw 90. Although not shown, the rear end of the left-side panel 13 is also fixed to the rear panel 15 by a screw 90. In this way, the right-side panel 12 and the left-side panel 13 are connected via the rear panel 15. As a result, even if an impact is applied, the rigidity of the right-side panel 12 and the left-side panel 13 is increased by being connected via the rear panel 15, making them less prone to deformation and breakage. For example, even if an impact is applied from the inside of the casing 10C, the right-side panel 12 and the left-side panel 13 are less likely to deform outwards because they are connected via the rear panel 15. Also, since the upright wall 141 of the lower panel 14 is located on the inside of the right-side panel 12 and the left-side panel 13, even if an impact is applied from the outside of the casing 10C, they are less likely to deform inwards. In this way, the right-side panel 12 and the left-side panel 13 are protected from deformation and damage due to impact.

[0110] As described above, in the casing 10C of the water heater 1C according to Embodiment 3, the lowest ends 123 and 153 of the right side panel 12, the left side panel 13, and the rear panel 15 are located outside the upright wall 141 of the lower panel 14, and are in contact with the upright wall 141 without being fixed to it. Therefore, when an impact load is applied, the lowest ends 123 and 153 of the right side panel 12, the left side panel 13, and the rear panel 15 can be displaced relative to the lower panel 14 in the direction along the upright wall 141, specifically in the vertical direction. In addition, the lowest ends 123 and 153 of the right side panel 12, the left side panel 13, and the rear panel 15 are less likely to come off the upright wall 141. As a result, the right side panel 12, the left side panel 13, and the rear panel 15 can prevent deformation and damage to the casing 10C due to impact.

[0111] Furthermore, in the casing 10C, the lower end portion of the front panel 11 has a folded portion 114 that faces the upright wall 141 of the lower panel 14 from the outside. The folded portion 114 is separated from the upright wall 141 and is not fixed to the upright wall 141. Therefore, the lower end portion of the front panel 11 can be displaced relative to the lower panel 14 when an impact load is applied. Also, because the folded portion 114 of the lower end portion of the front panel 11 faces the upright wall 141 of the lower panel 14 from the outside, it is difficult for it to come off the upright wall 141. As a result, the front panel 11 can prevent deformation and damage to the casing 10C due to impact.

[0112] Although the casing 10A-10C and water heater 1A-1C according to Embodiments 1-3 of this disclosure have been described above, the casing 10A-10C and water heater 1A-1C are not limited thereto.

[0113] For example, in Embodiments 1-3, the lower end portion of the right-side panel 12 is hook-shaped in cross-section by bending the right-side panel 12 itself into a Z-shape, for example, by sheet metal processing. However, the right-side panel 12 is not limited to this. As described in Embodiment 3, the right-side panel 12 has a lower end portion that extends from the side of the heavy object to the lower panel 14 and is located on the side of the lower panel 14, and this lower end portion is not fixed to the lower panel 14 but is displaced relative to the lower panel 14 when an impact load is applied. This is also true for the left-side panel 13 and the rear panel 15, as described in Embodiment 3. Therefore, the lower end portion of the right-side panel 12 may be hook-shaped by attaching a specific part. Similarly, the lower end portion of the rear panel 15 may also be hook-shaped by attaching other parts. Figures 26 and 27 show modified examples of the lower end portions of the right-side panel 12 and the rear panel 15.

[0114] Figure 26 is an enlarged cross-sectional view of the lower part of a modified right-side panel 12 of the water heater 1A according to Embodiment 1. Figure 27 is an enlarged cross-sectional view of the lower part of a modified rear panel 15.

[0115] As shown in Figure 26, the lower end portion of the right side panel 12 may have a hook-shaped member 80 that is inverted L-shaped in cross-section. In this case, the hook-shaped member 80 is provided on the inner wall surface of the lower end portion of the right side panel 12, and the hook-shaped member 80 has a base portion 801 fixed to the inner wall surface of the lower end portion of the right side panel 12 and a hook tip portion 802 extending downward from the base portion 801, and the distance D7 from the inner wall surface of the lower end portion of the right side panel 12 to the hook tip portion 802 may be greater than or equal to the thickness of the upright wall 141 of the lower panel 14. Furthermore, the upright wall 141 of the lower panel 14 may be sandwiched between the hook tip portion 802 and the right side panel 12. In this configuration, the lower end portion of the right side panel 12 can be displaced relative to the lower panel 14 when an impact load is applied to the casing 1A. Furthermore, it is preferable that the hook tip 802 of the hook-shaped member 80 has a chamfered portion 803 on the side with the base 801. This configuration facilitates the insertion of the upright wall 141 of the lower panel 14 between the hook tip 802 and the right-side panel 12 of the casing 1A, thereby improving the ease of assembly of the casing 1A.

[0116] Furthermore, as shown in Figure 27, the lower end portion of the rear panel 15 may have a hook-shaped member 81 that is inverted U-shaped in cross-section. In this case, the hook-shaped member 81 may be provided on the inner wall surface of the lower end portion of the rear panel 15. The hook-shaped member 81 has a base portion 811 that extends vertically and is fixed to its inner wall surface, a connecting portion 815 that extends inward from the upper end of the base portion 811, and a hook tip portion 812 that extends downward from the inner end of the connecting portion 815 parallel to the base portion 811, and the distance D8 from the base portion 811 to the hook tip portion 812 may be greater than or equal to the thickness of the upright wall 141 of the lower panel 14. The upright wall 141 of the lower panel 14 may be sandwiched between the base portion 811 and the hook tip portion 812. In this configuration, the lower end portion of the rear panel 15 can be displaced relative to the lower panel 14 when an impact load is applied to the casing 1A. Furthermore, the hook tip portion 812 of the hook-shaped member 81 may have a chamfered portion 813 on the side with the base portion 811, similar to the hook-shaped member 80 described above. Also, the base portion 811 of the hook-shaped member 81 may have a chamfered portion 814 on the side with the hook tip portion 812. In this configuration, the casing 1A facilitates the insertion of the upright wall 141 of the lower panel 14 between the hook tip portion 812 and the base portion 811, thereby improving the ease of assembly of the casing 1A.

[0117] Furthermore, the lower end portion of the right-side panel 12 may have a hook-shaped member 81 instead of a hook-shaped member 80. Similarly, the lower end portion of the rear panel 15 may have a hook-shaped member 80 instead of a hook-shaped member 81. In addition, although not shown, at least one of the lower end portions of the left-side panel 13 and the front panel 11 may have a hook-shaped member 80 or a hook-shaped member 81. Moreover, the hook-shaped members 80 and 81 are just examples of other parts as described in this disclosure.

[0118] Furthermore, in Embodiments 1-3, the lowest end portion 113 of the front panel 11 is located outside the upright wall 141 of the lower panel 14. However, the front panel 11 is not limited to this. The front panel 11, like the right side panel 12, the left side panel 13, and the rear panel 15, has a lower end portion that extends from the side of the heavy object to the lower panel 14 and is located on the side of the lower panel 14, as described in Embodiment 3. This lower end portion is not fixed to the lower panel 14, but is displaced relative to the lower panel 14 when an impact load is applied. For this reason, the lowest end portion 113 of the front panel 11 may be located inside the upright wall 141 of the lower panel 14, or it may be located outside the upright wall 141.

[0119] Furthermore, the presence or absence of an upright wall 141 on the lower panel 14 is optional. The lower panel 14 does not need to have an upright wall 141.

[0120] In Embodiment 1-3, the heat insulating member 54 is made of expanded polystyrene. However, it is optional whether or not the water heaters 1A-1C have the heat insulating member 54. Therefore, if the water heaters 1A and 1B have the heat insulating member 54, the heat insulating member 54 may be made of expanded polyurethane or glass wool.

[0121] Furthermore, in Embodiments 1-3, the casing 10A-10C has a front panel 11, a right-side panel 12, a left-side panel 13, and a rear panel 15. However, the casing 10A-10C is not limited to this. As described in Embodiment 3, in this disclosure, the front panel 11, the right-side panel 12, the left-side panel 13, and the rear panel 15, i.e., the side panels, have a lower end that extends from the side of the heavy object to the lower panel 14 and is located on the side of the lower panel 14, and the lower end is not fixed to the lower panel 14 but is displaced relative to the lower panel 14 when an impact load is applied. Therefore, the casing 10A-10C does not need to have all of the front panel 11, the right-side panel 12, the left-side panel 13, and the rear panel 15; for example, it is sufficient to have at least one of the side panels of the front panel 11, the right-side panel 12, the left-side panel 13, and the rear panel 15.

[0122] In this specification, a side panel refers to a panel positioned on the side of a heavy object, and examples of side panels include the front panel 11, the right side panel 12, the left side panel 13, and the rear panel 15. Furthermore, "side" refers to the part located on the side of a heavy object, for example, the part in the front, back, left, or right direction.

[0123] Furthermore, in Embodiment 1-3, the water heater 1A-1C is equipped with a heating unit 20 and a hot water storage unit 50 as heavy components. However, the water heater 1A-1C is not limited to this. The water heater 1A-1C only needs to be a heavy component; for example, it may not have a heating unit 20 but may have a hot water storage unit 50.

[0124] The hot water storage unit 50 has an insulating member 54, but the presence or absence of the insulating member 54 is optional. Furthermore, if the insulating member 54 is present, it is also optional whether or not it is formed from the top surface 541, the right side surface 542, the left side surface 543, and the bottom surface 544. Therefore, the hot water storage unit 50 may have an insulating member 54 formed only from the right side surface 542 and the left side surface 543, for example.

[0125] Furthermore, in Embodiments 1-3, a cushioning material 517 is sandwiched between the L-shaped bracket 512 and the lower panel 14. However, the water heaters 1A and 1B are not limited to this. The water heaters 1A and 1B only need to be heavy, so the presence or absence of the L-shaped bracket 512 and cushioning material 517 is optional. For example, the water heaters 1A and 1B may not have the cushioning material 517, and the L-shaped bracket 512 may be directly fixed to the lower panel 14.

[0126] This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of this disclosure. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of this disclosure. In other words, the scope of this disclosure is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent significance of the disclosure are considered to be within the scope of this disclosure.

[0127] This application is based on Japanese Patent Application No. 2024-169815, filed on 30 September 2024. The entire specification, claims, and drawings of Japanese Patent Application No. 2024-169815 are incorporated herein by reference.

[0128] 1A-1C Water heater, 2 Operator, 10A-10C Casing, 11 Front panel, 12 Right side panel, 13 Left side panel, 14 Lower panel, 15 Rear panel, 16 Upper panel, 17-19 Handle section, 20 Heating unit, 30 Heating circuit, 31 Expansion tank, 32 Multifunction device, 33 Pump, 34 Heat exchanger, 35 Booster heater, 36 Three-way valve, 40 Hot water supply circuit, 41 Heat exchanger, 42 Scale trap, 43 Pump, 44, 45 Piping, 50 Hot water storage unit, 51 Hot water storage tank, 52 Water supply piping, 53 Hot water supply piping, 54 Insulation material, 60 Outdoor unit, 70 Frame structure, 71 Lower frame section, 72 Upper frame section, 73-76 Support column section, 77 Beam section, 80, 81 Hook-shaped member, 90 Screw, 111 First bend, 112 Second bend, 113 Bottom end, 114 Folded back, 115 Bent section, 121 First bend, 122 Second bend, 123 Bottom end, 124 Extended section, 125 First bend, 126 Second bend, 127 Panel surface, 141 Upright wall, 151 First bend, 152 Second bend, 153 Bottom end, 511 Base, 512 L-shaped bracket, 513 Bolt, 514 Nut, 515 Bolt, 516 Nut, 517 Cushioning material, 541 Top surface, 542 Right side surface, 543 Left side surface, 544 Bottom surface, 545 Through hole, 546 Recess, 547, 548 Wall section, 771-773 Metal fitting, 801 Base section, 802 Hook tip section, 803 Chamfered section, 811 Base section, 812 Hook tip section, 813, 814 Chamfered section, 815 Connection section, CG Center of gravity, D1, D2, D5-D8 Distance, D3 Forward, D4 Backward, F1, F2 Rotational force, G Gravity, G1, G2 Gap.

Claims

A lower panel placed beneath the heavy object, At least one side panel positioned to the side of the aforementioned heavy object, A casing comprising, which houses the aforementioned heavy object inside, The side panel extends from the side of the heavy object to the lower panel and has a lower end located on the side of the lower panel, and this lower end is not fixed to the lower panel and is displaced relative to the lower panel when an impact load is applied. Casing. 　 The lower end of the side panel is located outside the casing, The casing according to claim 1. 　 The lower panel is provided on the outer edge and has an upright wall facing the lower end of the side panel. The casing according to claim 1 or 2. 　 The lower end of the side panel has a first bent portion that extends downward and then bends laterally, a second bent portion that extends laterally from the first bent portion and then bends downward, and a lowest end portion that extends downward from the second bent portion. The lowest end portion is opposite to the upright wall, The casing according to claim 3. 　 The lowermost portion is located above the first bent portion and is parallel to the panel surface extending downward. The casing according to claim 4. 　 The portion extending laterally from the first bent portion is located on the upright wall, The lowermost portion is located inside the casing, The casing according to claim 4 or 5. 　 The portion extending laterally from the first bend increases in direction as it moves laterally from the first bend. The second bent portion is located above the first bent portion. The casing according to any one of claims 4 to 6. 　 The first and second bent portions are bent at an acute angle. The casing according to any one of claims 4 to 7. 　 The side panel has a flat portion formed on its inner wall surface that extends in the vertical direction, The flat portion comes into contact with the heavy object when a rotational force is applied to the heavy object in the vertical direction, causing the heavy object to be displaced relative to the side panel. The casing according to any one of claims 1 to 8. 　 The aforementioned heavy object is a hot water storage tank for storing hot water. The casing according to any one of claims 1 to 9. 　 The lower end portion is formed by a component separate from the side panel. The casing according to any one of claims 1 to 10. 　 The lower panel is provided on the outer edge and has an upright wall facing the lower end of the side panel, The aforementioned other component includes a hook-shaped member that is hooked onto the upright wall and is displaceable relative to the upright wall. The casing according to claim 11. 　 At least one of the side panels is opposite to each other and includes two connected side panels, The casing according to any one of claims 1 to 12. 　 A casing according to any one of claims 1 to 13, The aforementioned heavy object has a hot water storage tank for storing hot water, A water heater equipped with the following features.

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