JP6988313B2 - How to manufacture the outer case for the hot water unit - Google Patents

Description

The present invention relates to a manufacturing method for manufacturing an outer case for a hot water unit used for accommodating a hot water device for generating or storing hot water in a hot water unit such as a hot water supply device or a cogeneration system. ..

As a specific example of a hot water unit configured as a hot water supply device, for example, a hot water device that heats hot water using a combustion gas generated by a burner is housed in an outer case (for example, Patent Documents 1 to 1). See 3). The outer case for such a hot water unit is generally manufactured by pressing a colored steel plate having a single color on the surface.

In such a hot water unit, for example, characters and symbols indicating the manufacturer name, type, or ability of the hot water unit are displayed on the outer case, and a wide range of the surface of the outer case is defined as the ground color of the surface of the colored steel plate. It may be required to have different predetermined colors. In this case, conventionally, after forming the components (exterior case main body and cover body) of the outer case by press molding, the components are painted by the spray method. As the paint, a solvent paint or a powder paint is used.

However, in the above-mentioned prior art, there is room for improvement as described below.

That is, when the conventional spray method painting means is used, masking treatment to the unpainted part and color matching of the paint are troublesome, and spraying work of the paint using the spray gun (air gun) is also troublesome. Yes, and it requires skill. Therefore, workability and productivity are poor. In addition, since the paint is sprayed on the masking part and the like, there is a lot of waste of the paint. Therefore, the manufacturing cost of the outer case and the manufacturing cost of the hot water unit are high. Such defects become more complicated as the pattern to be painted becomes more complicated, and become more prominent as the number of colors increases, making it difficult to express detailed patterns. Furthermore, the use of solvent paint or powder paint in spray painting has a large environmental load, and it is difficult to maintain a good working environment and to properly dispose of the paint.
Further, in the past, since the outer case is press-molded and then painted, there is a problem that it is difficult to properly apply a predetermined paint to the uneven portion of the outer case.
In the past, a transfer method coating method was also appropriately adopted, but according to this method, a transfer plate is required, resulting in high cost. There is also a problem that it is not suitable for painting a large area.

Japanese Unexamined Patent Publication No. 2012-32029 Japanese Unexamined Patent Publication No. 11-294867 Japanese Unexamined Patent Publication No. 2014-40950

The present invention has been conceived under the above-mentioned circumstances, and even when the outer case for the hot water unit is provided with a complicated pattern or the like, the present invention does not cause environmental pollution. It is an object of the present invention to provide a method for manufacturing an outer case for a hot water unit, which can manufacture the outer case with high productivity and at low cost by a simple work process.

In order to solve the above problems, the following technical means are taken in the present invention.

The method for manufacturing an outer case for a hot water unit provided by the present invention is to press a flat metal plate to form an outer case used for accommodating hot water equipment for hot water generation or hot water storage inside. A method of manufacturing an exterior case for a hot water unit, which comprises a pressing process for forming components and a painting process for painting any of letters, symbols, figures, or patterns on the components of the exterior case. a is, the coating process, by subjecting the ink-jet printing on the flat metal plate includes an ink jet printing process for forming an ink jet printing layer, the pressing step is performed after the inkjet printing step, and In the inkjet printing step, the portion of the planned area for the drawing process in which the thickness of the metal plate is made thinner than other portions is included in the inkjet printing layer. It is characterized in that the thickness is made thinner than the thickness of the inkjet printing layer of the other portion.

With such a configuration, the following effects can be obtained.
That is, the step of painting the constituent parts of the outer case includes an inkjet printing step of forming an inkjet printing layer, and this inkjet printing step can be easily provided by using an inkjet printer. Unlike conventional painting by the spray method, masking treatment on the outer case and color matching of the paint are not required, and no skill is required. Further, unlike the conventional transfer method painting, a transfer plate is not required and it is easy to paint a large area. Therefore, the productivity of the outer case can be improved. Further, since the inkjet printing layer can be provided only in a desired place, waste of the ink paint can be eliminated or reduced. As a result, it is possible to reduce the manufacturing cost of the outer case and, by extension, the manufacturing cost of the hot water unit. Furthermore, according to inkjet printing, it is possible to express patterns with complicated shapes and patterns with many colors in detail, which is more preferable for improving the appearance of the hot water unit. Compared with the conventional technology, it is possible to easily realize a reduction in the environmental load and a good working environment.
In addition, since inkjet printing is performed before the press process, unlike the conventional technology, it is possible to appropriately eliminate problems such as difficulty in painting (printing) on uneven portions formed by the press process. Is.
Further, when the inkjet printing process is performed before the metal plate is drawn, if the thickness of the entire inkjet printing layer in the planned drawing area is large and uniform, when the drawing is performed, the thickness of the inkjet printing layer is large and uniform. There is a risk that the inkjet print layer will peel off at the portion of the metal plate where the drawing amount is large (the portion of the drawn portion where the plate thickness is thinner than the other portions). On the other hand, according to the above configuration, it is possible to appropriately avoid such a risk.

In the present invention, preferably, the exterior case includes an exterior case body having an opening on at least one surface thereof, and a cover body attached to the exterior case body so as to close the opening. As the means for manufacturing the cover body, the painting step and the pressing step are carried out.

According to such a configuration, the design of the outer case can be efficiently improved by the step of painting the cover body of the outer case.

In the present invention, preferably, the pressing step includes a step of providing the metal plate with a burring hole in which the burring portion protrudes from the peripheral edge of the opening, and the area to be the burring portion in the inkjet printing step is included. , An inkjet printing layer connected to the inkjet printing layer provided in the peripheral portion thereof is provided.

According to such a configuration, the peripheral portion of the burring hole and the burring portion can be painted in a state of forming a series of connected colors or patterns, and the appearance of this portion can be improved. Is. Unlike the above configuration, for example, when the inkjet printing layer is provided only on the peripheral portion of the burring hole and the inkjet printing layer is not provided on the burring portion, the burring portion may be seen as an unsightly portion from the outside. According to the above configuration, it is possible to eliminate such a risk.

In the present invention, preferably, in the inkjet printing process, a mark for positioning the metal plate at the time of performing the pressing process is printed.

According to such a configuration, when the pressing process is performed, the metal plate can be positioned with reference to the positioning mark represented by the inkjet printing layer. Therefore, it is possible to accurately align the characters and patterns represented by the inkjet printing layer with the stamped portion.

In the present invention, preferably, the inkjet printing uses an ink containing an ultraviolet curable resin, and the process of applying the ink to the metal plate while moving the print head for inkjet printing. At the same time, the process of irradiating the ink applied to the metal plate with ultraviolet rays is executed.

According to such a configuration, it is possible to cure the inkjet printing layer at an early stage by irradiating with ultraviolet rays during the inkjet printing. If a new inkjet printing layer having a different color or the like is provided adjacent to the uncured inkjet printing layer, bleeding may occur, but according to the above configuration, such a risk may occur. It is possible not to.

In the present invention, preferably, the inkjet printing uses a thermosetting resin as an ink, and after the inkjet printing is completed, the thermosetting resin is cured by heating the inkjet printing layer. And after this curing, the pressing step is carried out.

According to such a configuration, the strength of the inkjet printing layer can be increased by heating the inkjet printing layer and curing the thermosetting resin after the inkjet printing is completed. Therefore, the inkjet print layer can be made to have excellent weather resistance and can be sufficiently strong to withstand the subsequent pressing process.

Other features and advantages of the invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings.

(A) is a side view showing an example of a hot water unit provided with an outer case manufactured by the manufacturing method according to the present invention, and (b) is an exploded perspective view of the outer case shown in (a). .. (A) is a front view of the cover body of the exterior case shown in FIG. 1, and (b) is a front view of the cover body in a state where the inkjet printing layer is omitted. (A) is a cross-sectional view taken along the line IIIa-IIIa of FIG. 2 (a), FIG. 2 (b) is a cross-sectional view of a main part of IIIb-IIIb of FIG. It is the cross-sectional view of the main part of IIIc-IIIc of FIG. It is a rear view of the cover body shown in FIGS. 1 and 2 (a). (A) to (e) are explanatory views showing an example of the manufacturing method according to the present invention, and correspond to a series of work steps of the cover body manufacturing method shown in FIGS. 1 and 2 (a). It is sectional drawing of the main part which shows an example of the color steel plate used for manufacturing the cover body shown in FIG. 1 and FIG. 2 (a). (A) is a perspective view showing an example of a schematic configuration of a printer used for inkjet printing, (b) is a view of arrow VIIb of (a), and is a print head of the printer shown in (a). It is a figure which shows the schematic structure of. FIG. 3 is a cross-sectional view of a main part showing an example of a work process for obtaining the structure of FIG. 3 (c).

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

First, in order to facilitate understanding, the configuration of the outer case C for the hot water unit manufactured by the manufacturing method of the present embodiment and the hot water unit U provided with the outer case C will be described.

In FIG. 1, the hot water unit U is a hot water supply device, and has a configuration in which a hot water device 1 for generating hot water is housed in an outer case C. The hot water device 1 includes a heat exchanger 10 through which hot water flows, a burner 11 for heating the hot water in the heat exchanger 10, and a fan 12 for supplying combustion air to the burner 11.

The exterior case C includes a rectangular box-shaped exterior case main body 2 having an opening 20 on the front surface, and a cover body 3 (front cover body) that closes the opening 20. The cover body 3 is detachably attached to the front surface portion of the outer case body 2 by using, for example, a screw body 9 such as a screw and screw insertion holes 31 and 21 through which the cover body 3 is inserted.

In the present embodiment, the inkjet printing layer 4 (the portion having a halftone dot pattern or a wavy line pattern in the figure) is provided on the cover body 3. However, it is not provided on the outer case main body 2. Therefore, hereinafter, the configuration of the cover body 3 will be described in detail, and the description of the outer case main body 2 will be omitted. However, as will be described later, it goes without saying that the outer case main body 2 may be provided with an inkjet printing layer.

The cover body 3 has a structure in which an inkjet printing layer 4 (4a to 4g) is provided on a color steel plate 30 (an example of a metal plate) which will be described later and is press-molded. However, in the production of the cover body 3 in the present embodiment, as will be described later, the color steel plate 30 is provided with the inkjet printing layer 4, and then the press processing is performed.

The cover body 3 has a panel shape having a substantially rectangular front view, is surrounded by the outer peripheral flange portion 32 and the outer peripheral flange portion 32, and is in front of the outer peripheral flange portion 32 (on the front side of the outer case C). It is provided with a bulging portion 33. The outer peripheral flange portion 32 is a portion for abutting on the substantially rectangular frame-shaped flange portion 22 provided on the front surface portion of the outer case main body 2, and as shown in FIG. 3A, the outer peripheral flange portion 32 is on the outer edge portion thereof. Is connected with a folded portion 32a formed by hemming.

The bulging portion 33 of the cover body 3 occupies most of the cover body 3, and the bulging portion 33 has a bulge portion 33.
An air supply port 34 and an exhaust port 35 are provided (see also FIG. 2). The air supply port 34 is a portion that allows outside air to flow into the outer case C. The exhaust port 35 is a portion for discharging the exhaust gas after heat recovery by the heat exchanger 10 to the outside of the outer case C, and as shown in FIG. 3C, a cylindrical burring portion is provided on the peripheral portion thereof. 35a is formed as a series of burring holes. The air supply port 34 can also be a burring hole like the exhaust port 35.

The inkjet printing layer 4 is a coating film layer provided by using the inkjet printer 8 as described later. As the ink for inkjet printing, a water-based pigment ink or a solvent-based pigment ink can be used, but in the present embodiment, an ink containing an ultraviolet curable resin and a thermosetting resin is used.

The inkjet printing layer 4 includes the inkjet printing layers 4a to 4d representing a predetermined pattern D1 such as a penguin, and characters such as a manufacturer, model, or trademark of the hot water unit U, which are provided on the surface of the cover body 3. An inkjet print layer 4e representing D2 (in the drawing, "AABBCC" as an example) is provided. Further, an inkjet printing layer 4f representing a positioning mark D3 at the time of press working, which will be described later, is provided at the four corners of the cover body 3. The positioning mark D3 is shown in the + shape in the drawing, but is not limited thereto. Further, the positioning mark D3 may be provided on the back surface of the cover body 3 in place of or in addition to the front surface of the cover body 3.

As shown in FIG. 4, the back surface of the cover body 3 is further provided with an inkjet printing layer 4g showing the electrical wiring diagram D4 of the hot water device 1. Instead of or in addition to the electrical wiring diagram D4, it is also possible to have a configuration showing a piping diagram of the hot water device 1. Although the illustration is omitted, the back surface of the cover body 3 may be further provided with an inkjet printing layer showing specifications, cautionary notes, etc. of the hot water unit U, in addition to the electrical wiring diagram D4 and the piping diagram. It is possible.

As shown in FIG. 6, the color steel plate 30 as a raw material of the cover body 3 is a plated steel plate 30a, a white paint layer 30b laminated on the surface of the plated steel plate 30a, and a plated steel plate. It is a multi-layer structure having a coating layer 30c on the back side as a service coat laminated on the back surface of 30a. The inkjet printing layers 4a to 4e have colors different from those of the white-based front paint layer 30b, and represent the pattern D1 such as the appearance of the penguins and the characters D2. The white portion in FIG. 2A is a portion of the front paint layer 30b of the color steel plate 30 that has not been subjected to inkjet printing.

The entire area of the inkjet printing layer 4a is basically formed to have the same color and the same thickness, but as shown in FIG. 2D, the peripheral wall portion 33a (outer peripheral flange portion 32) of the bulging portion 33 is formed. The thickness ta of the corner portion 33a'of the wall portion erecting from the wall portion) is thinner than the thickness tb of the other portion of the peripheral wall portion 33a and the thickness of the portion other than the peripheral wall portion 33a. The bulging portion 33 is formed by drawing, and in this drawing, the amount of elongation at the corner 33a'of the peripheral wall portion 33a is the largest (the corner 33a'is the "drawing portion" in the present invention. Of these, it corresponds to an example of "a part where the plate thickness is formed thinner than other parts"). Corresponding to this, if the thickness ta of the inkjet printing layer 4a in that portion is reduced, the peeling prevention effect of the inkjet printing layer 4a can be obtained, as will be described later. When the drawing amount (elongation amount) of the peripheral wall portion 33a is increased in order to increase the bulging amount of the bulging portion 33, the thickness tb of the portion other than the corner portion 33a'of the peripheral wall portion 33 is printed by inkjet printing. It may be thinner than the thickness of other parts of the layer 4a.

The inkjet printing layer 4b is provided in the peripheral portion of the exhaust port 35, and as described with reference to FIG. 3C, the exhaust port 35 is formed as a burring hole having a burring portion 35a. .. On the other hand, a part of the inkjet printing layer 4b has a burring portion 35.
It is also provided on the inner surface of a. As a result, the peripheral portion of the exhaust port 35 and the inner surface of the burring portion 35a can be aligned in the same color or pattern, and the appearance of the exhaust port 35 and its peripheral portion can be improved.

The inkjet printing layer 4e is provided on the front surface of a stepped portion 36 (see also FIGS. 2 (b) and 3 (b)) that three-dimensionally represents the character D2. More specifically, the stepped portion 36 is a portion in which the character D2 is three-dimensionally formed by partially extruding a part of the color steel plate 30 by press working, and the inkjet printing layer 4e is a portion thereof. It is provided on the front surface portion of such a step push portion 36. The stepped portion 36 has a convex shape on the front side in which a part of the colored steel plate 30 is pushed out to the front side of the cover body 3 and a front surface in which a part of the colored steel plate 30 is pushed out to the rear side of the cover body 3. There is a laterally concave form, but any of them may be used.

Next, an example of the method for manufacturing the cover body 3 described above will be described.

First, as shown in FIG. 5A, a flat plate-shaped colored steel plate 30 described with reference to FIG. 6 is prepared as a raw material for the cover body 3. Next, the color steel plate 30 is subjected to inkjet printing. As a result, as shown in FIG. 3B, the inkjet printing layer 4 is provided. Specific examples of the inkjet printing layer 4 are as described above.

Inkjet printing is performed using, for example, an inkjet printer 8 as shown in FIG. 7A. In the inkjet printer 8, the print head 80 is movable in the x and y directions orthogonal to each other on the upper side of the mounting table 81 on which the color steel plate 30 is mounted and supported. As shown in FIG. 7B, the print head 80 includes a plurality of inkjet nozzles 82 that atomize an inkjet paint of a predetermined color and spray it toward the color steel plate 30, and this point is conventionally known. However, in the present embodiment, a pair of ultraviolet light sources 83 (83a, 83b) are further provided.

For example, when performing inkjet printing while moving the print head 80 in the x1 direction of the figure as the main scanning direction, the ultraviolet light source 83a on the rear side in the main scanning direction is made to emit light, and the area immediately after the inkjet printing is performed. Irradiate with ultraviolet rays. Since the inkjet printing layer 4 contains an ultraviolet curable resin, the inkjet printing layer 4 can be rapidly cured (cured to the extent that bleeding does not occur, which will be described later) by irradiation with the ultraviolet rays. Therefore, it is possible to prevent problems such as uncured inkjet printing layers 4 having different colors being mixed with each other and causing bleeding. When the inkjet printing is carried out in the direction opposite to the x1 direction described above, the same effect as described above can be obtained by causing the ultraviolet light source 83b to emit light instead of the ultraviolet light source 83a.

When the inkjet printing layer 4a is provided, the thickness ta of the color steel plate 30 is set to the thickness tb of the other portion at the planned portion of the peripheral wall portion 33a shown in FIG. 3D at the corner portion 33a'. Make it thinner than.

After the inkjet printing on both the front and back surfaces of the color steel plate 30 is completed, as shown in FIG. 5 (c), the color steel plate 30 is heated to dry the inkjet print layer 4, and the inkjet print layer 4 is printed. The contained thermosetting resin is cured. This heating is performed using, for example, a heating furnace. By such a treatment, it is possible to increase the strength of the inkjet printing layer 4 to improve the weather resistance, and it is also possible to improve the durability against the press working to be performed thereafter.

Next, the colored steel plate 30 is subjected to drawing as a press working to form the outer peripheral flange portion 32 and the bulging portion 33 as shown in FIG. 5 (d). After that, as shown in FIG. 5 (e), a press process for forming the air supply port 34, an exhaust port 35, a step push portion 36, and the like, a trimming process for removing an excess portion of the outer peripheral flange portion 32, and then a trimming process are performed. Hemming processing etc. is performed.

The cover body 3 described above can be appropriately manufactured by a series of work steps as described above.
In the above-mentioned pressing process, it is possible to accurately position the colored steel sheet 30 with reference to the positioning mark D3. Further, the work of forming the exhaust port 35 is performed by using the punch 7a and the die 7b, for example, as shown in FIG. 8, but not only the peripheral portion of the planned formation portion of the exhaust port 35 but also the formation target of the exhaust port 35. Since the inkjet printing layer 4b is also provided in a series at the locations, as shown in FIG. 3C, the inkjet printing layer 4b is provided in a series from the peripheral portion of the exhaust port 35 to the burring portion 35a. It can be realized properly.

Since the exterior case C provided with the cover body 3 has a pattern D1 such as a penguins on the front surface of the cover body 3, it is compared with, for example, a case in which the surface of the cover body 3 has a single color and no pattern. Then, the design becomes excellent. Further, since the inner surface of the burring portion 35a of the exhaust port 35 is continuously painted on the peripheral portion of the exhaust port 35, the inside of the burring portion 35a has a different color from the peripheral portion of the burring portion 35a. The appearance is better than in the case. Further, in the corner portion 33a'of the peripheral wall portion 33a, a part of the color steel plate 30 is greatly extended by drawing processing, but the thickness ta of the inkjet printing layer 4 in this portion is thinner than the thickness tb of the other portion. Therefore, it is possible to prevent the inkjet printing layer 4 from being easily peeled off by the above-mentioned drawing process.

Since the electrical wiring diagram D4 or the piping diagram is represented by the inkjet printed layer 4g on the back surface of the cover body 3, it is convenient for maintenance work and the like. For example, if a sheet on which an electrical wiring diagram is printed is attached to the back surface of the cover body 3, the sheet may be damaged or peeled off from the cover body 3 and lost. If so, there is no such risk.

Since the coating film layer representing the design D1, the character D2, the positioning mark D3, the electrical wiring diagram D4, and the like of the cover body 3 is the inkjet printing layer 4, the inkjet printer 8 as described above is used. It can be easily installed. For example, unlike painting by the spray method, masking treatment and color matching of paint are not required, and no skill is required. Therefore, it is possible to improve workability and productivity. In addition, it is easy to change the design of the design D1 and the like, and it is suitable for small-lot, high-mix production. Further, according to inkjet printing, there is no or little waste of ink paint, and the environmental load is small.
Further, since the pressing process is performed after the inkjet printing is completed, there is no problem that it becomes difficult to paint the uneven portion formed by the pressing process.

The present invention is not limited to the contents of the above-described embodiments. The specific configuration of each working process of the method for manufacturing the outer case for the hot water unit according to the present invention can be variously changed within the scope of the present invention.

In the above-described embodiment, an example in which inkjet printing is applied only to the cover body 3 is shown, but in the present invention, inkjet printing may be applied to the outer case main body 2 instead of or in addition to the case. Of course. The specific contents such as characters and patterns represented by the inkjet printing layer of the present invention are not limited, and at least one of characters, symbols, figures, or patterns may be represented.

The hot water unit referred to in the present invention is a hot water storage tank in which a hot water storage device such as a hot water storage tank is housed in the outer case instead of a hot water supply device or the like in which a hot water device for hot water generation is housed in the outer case. It is a concept that includes units and the like. Therefore, the exterior case is not limited to a combination of the front opening-shaped exterior case main body and the cover body that closes the front opening portion.
A flat metal plate is used as the material of the outer case, and a material other than the color steel plate can be used as the metal plate.

U Hot water unit C Exterior case D1 Design D2 Character D3 Positioning mark D4 Electrical wiring diagram 1 Hot water equipment 2 Exterior case body 20 Opening (of the exterior case body)
3 Cover body 30 Color steel plate 33a Peripheral wall 33a'Corner wall 35 Exhaust port (burring hole)
35a Burling part 4 (4a-4g) Inkjet printing layer

Claims (6)

A press process in which a flat metal plate is pressed to form components of an exterior case used to house hot water equipment for hot water generation or hot water storage inside.
A painting process in which characters, symbols, figures, or patterns are painted on the components of the exterior case.
It is a manufacturing method of the outer case for the hot water unit, which has
The coating step includes an inkjet printing step of forming an inkjet printing layer by applying inkjet printing to the flat metal plate.
The pressing step is performed after the inkjet printing step and includes a step of drawing the metal plate.
In the inkjet printing step, the thickness of the inkjet printing layer in the portion of the planned area to be drawn where the thickness of the metal plate is made thinner than the other portion is set to the thickness of the inkjet printing layer in the other portion. A method of manufacturing an outer case for a hot water unit, which is characterized by being thinner than the above. The method for manufacturing an outer case for a hot water unit according to claim 1.
The exterior case includes an exterior case body having an opening on at least one surface thereof, and a cover body attached to the exterior case body so as to close the opening.
A method for manufacturing an outer case for a hot water unit, which carries out the painting step and the pressing step as a means for manufacturing the cover body. The method for manufacturing an outer case for a hot water unit according to claim 1 or 2.
The pressing step includes a step of providing the metal plate with a burring hole in which the burring portion protrudes from the peripheral edge of the opening.
A method for manufacturing an exterior case for a hot water unit, in which an inkjet printing layer connected to an inkjet printing layer provided in a peripheral portion thereof is provided in a planned area to be a burring portion in the inkjet printing step. The method for manufacturing an outer case for a hot water unit according to any one of claims 1 to 3.
In the inkjet printing process, a method for manufacturing an outer case for a hot water unit, which prints a mark for positioning the metal plate at the time of performing the pressing process. The method for manufacturing an outer case for a hot water unit according to any one of claims 1 to 4.
In the inkjet printing, an ink containing an ultraviolet curable resin is used as the ink, and the ink is applied to the metal plate in the process of applying the ink to the metal plate while moving the print head for inkjet printing. A method for manufacturing an outer case for a hot water unit, which simultaneously executes a process of irradiating the printed ink with ultraviolet rays. The method for manufacturing an outer case for a hot water unit according to any one of claims 1 to 5.
The inkjet printing uses a thermosetting resin-containing ink as the ink.
A method for manufacturing an outer case for a hot water unit, in which the thermosetting resin is cured by heating the inkjet printing layer after the inkjet printing is completed, and the pressing step is performed after the curing.

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