JP4349472B2 - Manufacturing method of heat insulation box - Google Patents

Description

  The present invention relates to a method for producing a heat insulating box by injecting a foam stock solution between an outer box and an inner box.

The heat insulation box is composed of an outer box (outer plate), an inner box, and a heat insulating material that satisfies them. When manufacturing such a heat insulating box, in order to spread the heat insulating material over the entire surface, it is common to use a liquid heat insulating material that is solidified by a chemical reaction over time.
In this case, in order to prevent the liquid heat insulator from leaking out from the gap generated at the abutting portion between the outer box and the inner box, it is necessary to apply a sealing material so as to close the gap after the assembly. For example, as shown in Japanese Patent Application Laid-Open No. 61-120973, it is conceivable to apply using a long and narrow needle gun. However, such a gap is located at a position where the nozzle easily interferes with the material to be applied. Cannot be applied, so usually done manually to be cautious of the work. However, in manual work, quality variation due to individual differences is large, work is time consuming and inefficient, and seal material is applied from one side, so the gap between the inner and outer boxes of different materials is particularly important. There was a problem that it was difficult to seal securely. As a method for solving such a problem, there is, for example, Japanese Patent Application Laid-Open No. 58-95179.

  In Japanese Patent Laid-Open No. 58-95179, when a steel sheet wound in a coil shape is pulled out, a synthetic resin for sealing with an extrusion molding machine is applied to a portion that is abutted against an inner box or the like when the steel sheet is bent. A method is shown in which a soft vinyl chloride resin material is attached, and then a steel sheet is cut and formed.

  However, in the method disclosed in Japanese Patent Application Laid-Open No. 58-95179, an excess of the sealing material adhering to the steel plate by the extruder is removed by a notch die in the next process. Since the range in which the gap is generated is narrow, most of the sealing material is discarded. In addition, although vinyl chloride resin is soft, it is difficult to be deformed. Therefore, the inner box may be pressed and deformed when the inner box is inserted, and a sufficient sealing effect may not be obtained.

  The present invention has been made in order to solve these problems, and is capable of automation, and in particular, the foam stock solution from the gap between the inner box and the outer box while reducing the cost by using the sealing material as a minimum requirement The purpose is to ensure the prevention of leakage.

  The first step to form an outer plate with notches in two opposing long sides by cut-pressing a rectangular metal sheet, and the flange and lower flange are formed by roll forming the long sides The second step, the third step of applying foamed rubber to the upper surface of the bottom of the flange located at a distance of 300 mm or less from the notch part, and forming the outer box by bending the outer plate into a gate shape at the notch part The fourth step, the fifth step of inserting the inner box into the outer box, the sixth step of attaching the bottom plate and the back plate, and leaving in the air in the space consisting of the outer box, the inner box and the back plate. And a seventh step of injecting a foam stock solution that reaches a viscosity of 300 cps in 3 to 6 seconds from the point of time.

  The first step to form an outer plate with notches in two opposing long sides by cut-pressing a rectangular metal sheet, and the flange and lower flange are formed by roll forming the long sides The second step, the third step of applying foamed rubber to the upper surface of the bottom of the flange located at a distance of 300 mm or less from the notch part, and forming the outer box by bending the outer plate into a gate shape at the notch part The fourth step, the fifth step of inserting the inner box into the outer box, the sixth step of attaching the bottom plate and the back plate, and leaving in the air in the space consisting of the outer box, the inner box and the back plate. And a seventh step of injecting a foam stock solution that reaches a viscosity of 300 cps in 3 to 6 seconds from the point of time, so that it is not necessary to apply a sealant to the corner after molding into a gate shape, The coating material interferes Nor. In addition, when the inner box is inserted into the outer box, the tip of the inner box is sealed from both sides with a sealing material, so the sealing effect is high and the amount of sealing material used can be reduced because it is selectively applied only to the notch. In addition, the foam is pre-applied with foamed rubber and the tip of the inner case is sealed from both sides, so it is sealed securely, and because it is elastic, it is distorted due to the difference in material between the inner box and the outer plate. Follow up with certainty.

Embodiment 1 FIG.
An embodiment of the present invention will be described with reference to FIGS. 1 is a flowchart showing the flow of a method for manufacturing a heat insulating box, FIG. 2 is an explanatory view of the manufacturing process, FIG. 3 is a sectional view of the heat insulating box, FIG. 4 is a block diagram showing the structure of the outer plate, and FIG. FIG. 6 is a configuration diagram showing the configuration of the front flange and inner box of the corner portion, FIG. 7 is a configuration diagram showing the configuration of the outer plate after applying the sealing material, and FIG. 9 is a graph showing the relationship between the foam stock solution and the application distance of the sealing material, FIG. 9 is a configuration diagram showing the appearance of the seal part in a state of bending and inserting the inner box, and FIG. 10 is a cross-sectional view showing the seal state after application of foam rubber FIG.

First, the manufacturing method of this invention is demonstrated based on FIG.1 and FIG.2. In the first step, a rectangular cut plate made by cutting a steel plate is cut-pressed to form the outer plate 1 (S1). Next, in the second step, the long side of the outer plate 1 (parallel to the surface forming the side surface of the heat insulation box when bent) is formed by roll forming to form a single flange portion and a double flange portion. An outer plate 1 having a front flange 2 is created (S2). Next, in the third step, foam rubber is applied to a predetermined portion of the front flange 2 with the application nozzle 3 (S3). Next, in a fourth step, bending into a gate shape is performed (S4). Next, in the fifth step, the inner box 4 is inserted (S5). Next, in the sixth step, the bottom plate 5 made of steel plate is assembled (S6). Next, in the seventh step, the back plate 6 is attached (S7). Next, in an eighth step, a urethane foam stock solution is injected as a foaming stock solution into the space composed of the outer plate 1, the inner box 4 and the back plate 6 by the injection nozzle 7 (S8). This foams by a chemical reaction and solidifies, thereby increasing the heat insulation of the box.
Thus, a heat insulation box is manufactured. In addition, sectional drawing of the heat insulation box after the last process in FIG. 1 or FIG. 2 is as FIG.

  As described above, the present invention includes a step of applying foamed rubber in the third step after roll forming and before gate-shaped bending. This process will be described with reference to FIGS.

First, the leakage location that occurs when the foam stock solution is injected if no foam rubber is applied will be described.
The outer plate 1 shown in FIG. 4 is formed by a cut press or roll forming, and is provided with a front flange portion 2. The front flange portion 2 is provided with a screw hole 8 and a notch portion 9, which corresponds to the initial state of the outer plate 1 in the third step. As indicated by a two-dot chain line in the figure, the notch 9 corresponds to a corner portion of the heat insulating box after bending.

Next, FIG. 5 shows a structure in which the inner box 4 is incorporated in the outer box 1, that is, the state of S6. In the figure, as shown in the X-X cross-sectional view, the inner box 4 to which the partition plate 10 is attached in advance is composed of a single flange portion 11 and a double flange of the front flange 2 of the outer plate 1 made by the roll forming of S2. It is sandwiched between the parts 12 and fixed with screws 13. A gap 15 is formed in the flange lower portion 14 which is a steel plate portion connecting the single flange portion 11 and the double flange portion 12 of the front flange 2 due to the bending process. Furthermore, a gap 16 is also formed in the double flange portion 12. Therefore, the foam undiluted solution may leak outside through the screw holes 8 through these gaps, and it is necessary to reliably close the gaps 15 at the part where the partition plate 10 is attached (around the screw holes 8).
In the drawing, the YY sectional view shows a contact portion between the front flange 2 and the inner box 4 in a portion without the screw hole 8 for comparison.

Next, FIG. 6 shows a structure of a corner portion (corresponding to the notch portion 9 in FIG. 4) when the outer plate 1 is bent into a gate shape. The cutout portion 9 in FIG. 4 is provided with a cutout 17 on one side of the cutout in order to reduce a gap when the cutout portion 9 is folded and overlapped. However, even with this consideration, the gap 18 is generated. Accordingly, the foam stock solution entering from the gap 15 passes through the gap 16 inside the double flange portion 12 and leaks out from the gap 18 to the outside. For this reason, it is also necessary to reliably close the gap 15 at the notch 9.
For reference, FIG. 6 also shows a state of a ZZ cross section as an example of a cross sectional state in the vicinity of a corner portion.

  Further, as shown in FIGS. 4 and 6, the notch portion 9 has the single flange portion 11 removed so as not to interfere during bending, so the inner box is sandwiched and fixed between the single flange portion 11 and the double flange portion 12. Can not do it. Accordingly, a gap 20 is generated between the front end portion 19 of the inner box 4 and the front flange portion 2, and a gap is also generated between the double flange portion 12 and the inner box 4. The stock solution leaks to the outside. For this reason, it is necessary to block the gap 20 reliably.

  In this way, the foam stock solution leaks are caused by the gap 15 between the front flange portion 2 and the outer plate 1 near the screw hole 8 and the inner box 4 and the front flange portion 2 near the notch 9. The gap 20 is. However, if all of the foam rubber (seal material) is applied along the front flange 2 of the outer plate 1 from the end to the end in order to close these gaps, a large amount of foam rubber is required, which increases the material cost. It will end up.

  Thus, when each part is examined, it can be readily understood that the foam 20 should be applied to the gap 20 only in the portion corresponding to the notch 9. On the other hand, the foam stock solution that has entered from the gap 15 flows through the gap 16 of the double flange portion 12 and leaks from the portion that opens to the outside. However, since this gap 16 is narrow, it flows depending on the characteristics of the foam stock solution. The distance that can be changed. That is, when a foam stock solution having high fluidity is used, the distance to be taken into consideration is long, and when a foam stock solution having low fluidity is used, the distance may be short.

Therefore, as shown in FIG. 7, it is only necessary to apply foamed rubber to each leakage location by an appropriate distance (A in FIG. 7). In addition, since this distance changes with the characteristics (curing time) of a foam stock solution, in order to obtain | require distance, the following experiment was conducted.
First, the foam stock solution is divided into 12 types from the time required to reach a viscosity of 300 cps in the air (hereinafter, the viscosity reaches 300 cps). Subsequently, each of the classified foam stock solutions is poured into a heat insulating box, and the distance of the leaked portion is measured to obtain an appropriate application distance of the sealing material. At this time, in order for the foam stock solution to sufficiently exhibit the heat insulation ability, it is necessary to fill all the predetermined spaces in the heat insulation box after foaming. As the quality is affected. Therefore, this point is also confirmed.
FIG. 8 shows a graph of the relationship between the type of foam stock solution and the application distance of the sealing material and the quality of the experiment. The horizontal axis of the graph represents the viscosity reaching time of 300 cps, and the vertical axis represents the coating distance necessary for preventing leakage of the foam stock solution. Moreover, the gray area | region shows the state in which a void exists in a heat insulation box in a graph. Furthermore, since the foam stock solution with a viscosity of 300 cps reaching time of 11 seconds or more continues to have a good fluidity for a long time, it is necessary to apply a sealing material along the flange accordingly. The experiment was conducted at 20 ° C.

As a result of this experiment, it is found that if a foam stock solution having a viscosity of 300 cps reaching time of 3 to 10 seconds is selected after being taken out into the atmosphere, it is not necessary to apply the whole surface along the flange. Further, when the viscosity reaches 300 cps from 1 second to 5 seconds, the increase in the coating distance of the sealing material is about 80 mm at maximum even if the time is increased by 1 second, but from 7 seconds to 10 seconds, The increase in distance is at least 120 mm and tends to increase in a quadratic curve.
From this, when considering the change in the viscosity reaching time of 300 cps due to the difference between the experimental environment and the manufacturing process environment while shortening the coating distance of the sealing material and suppressing the generation of voids, the foam stock solution has a viscosity reaching time of 300 cps. In this case, a coating distance of about 300 mm is sufficient.

When assembled after actual application, the appearance is as shown in FIG. B in the figure shows the state of the ceiling corner immediately after bending the outer plate 1. C shows the state of the ceiling corner after the inner box 4 is inserted. This is shown in more detail in FIG. 10, in which (a) shows a sealed state with foamed rubber at the notch. Compared to FIG. 6, it can be seen that the gap 15 and the gap 20 are closed. In particular, the gap 20 between the outer plate 1 and the inner box 4 is different in material from the gap between the flanges formed by bending a single plate (the outer plate 1 is a steel plate and the inner box 4 is a synthetic resin). Deformation due to installation environment is difficult to predict due to differences in physical properties. Therefore, since it is considered that the gap changes during use, as shown in the figure, when the sealing material (foam rubber) 21 is attached to the upper surface of the flange lower portion 14, the inner box 4 is inserted into the outer box. Sometimes, the tip 19 of the inner box 4 bites into the applied foamed rubber. As a result, the tip 19 is reliably sealed from both sides. Further, since the sealing material 21 is a rubber body, it has good followability to deformation of a plate or the like.
On the other hand, in the figure, (b) shows a sealed state around the screw hole 8, but in this case, since there is the single flange portion 11, it is sufficient that the seal portion 21 exists so as to close the gap 15. .

The third process, which is such a process, allows the sealing material to be applied in a substantially flat state before bending, so that the injection nozzle 7 does not interfere and is automated using a robot or the like. Can be easily done.
Further, by eliminating the interference factor, the injection nozzle 7 can be controlled to change the injection angle and the application speed after approaching the front flange 2 of the outer plate 1 in the immediate vicinity. Will improve.

  Furthermore, since the portion that must be applied can be within the necessary and sufficient range, it is not necessary to apply a wide area, and the consumption of the sealing material is reduced.

  Further, the outer plate and the inner box, which are different materials, can be reliably sealed, and since foamed rubber is used, the followability to deformation is improved, and long-term reliability is improved. Moreover, also in prevention of the clearance gap between the outer plate and the flange which are the same kind of materials, it is effective in preventing leakage of the foam stock solution by improving followability.

It is a flowchart which shows the flow of manufacture of a heat insulation box. It is explanatory drawing of the manufacturing process of a heat insulation box. It is sectional drawing of a heat insulation box. It is a block diagram which shows the structure of an outer plate | board. It is a block diagram which shows the structure of the part which connects a partition plate. It is a block diagram which shows the structure of the front flange and inner box of a corner part. It is a block diagram which shows the structure of the outer plate | board after sealing material application | coating. It is a graph which shows the relationship between the foam stock solution and the application distance of a sealing material. It is a block diagram which shows the external appearance of the seal | sticker part in the state which inserted the inner box. It is sectional drawing which shows the sealing state after foaming rubber application.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Outer plate, 2 Front flange, 3 Coating nozzle, 4 Inner box, 5 Bottom plate, 6 Back plate, 7 Injection nozzle, 8 Screw hole, 9 Notch part, 10 Partition plate, 11 Single flange part, 12 Double flange part, 13 screw, 14 flange lower part, 15 gap, 16 gap, 17 uncut, 18 gap, 19 tip, 20 gap, 21 seal part.

Claims (1)

A first step of forming an outer plate having a notch in two opposite long sides by cut-pressing a rectangular metal thin plate;
A second step of forming a flange portion and a flange lower portion by roll forming the long side;
A third step of applying foamed rubber to the upper surface of the lower portion of the flange located at a distance of 300 mm or less from the notch portion;
A fourth step of forming the outer box by bending the outer plate into a gate shape at the cutout portion;
A fifth step of inserting an inner box into the outer box;
A sixth step of attaching the bottom plate and the back plate;
And a seventh step of injecting a foam stock solution that reaches a viscosity of 300 cps in 3 to 6 seconds after being left in the air in the space consisting of the outer box, the inner box, and the back plate. A method for producing a heat-insulated box body.

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