JPS61190276A - Manufacture of heat-insulating door - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a heat insulating door applied to refrigerators and the like.

[Technical Background of the Invention] Conventionally, a heat insulating door for a refrigerator or the like has a structure in which a urethane resin is foamed and filled as a heat insulating material into an outer shell consisting of an outer panel and an inner panel.

[Problems with the Background Art] However, with this conventional configuration, carbon dioxide gas with high thermal conductivity is trapped in the urethane resin bubbles when the urethane resin is foam-filled, so the insulation performance cannot be said to be sufficient. there were. In addition, because the outer panel, inner panel, and foamed urethane resin are required to construct the heat-insulating door, not only does the number of parts increase, but the number of manufacturing and assembly steps for each of these components also increases, which increases costs accordingly. There was a problem.

[Object of the Invention] The present invention has been made in view of the following two circumstances, and its purpose is to improve the heat insulation performance and to form an outer shell without using an outer panel or an inner panel. It is an object of the present invention to provide a method for manufacturing a heat insulating door, which can reduce the number of valve parts and the manufacturing man-hours and assembly man-hours associated therewith, thereby reducing costs.

[Summary of the Invention] In order to achieve the above object, the present invention provides a mold having a cavity shaped to correspond to the external shape of the heat insulating door, and when heated to a predetermined temperature or higher, melts into the mold. After carrying out the step of storing the filler made of powder or granules and the step of evacuating the inside of the mold, the portion of the filler that comes into contact with the mold is heated and melted, and the molten portion is removed. It consists of an outer shell that maintains the internal vacuum state by cooling and solidifying.

Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, reference numeral 1 denotes a heat insulating door for a refrigerator, for example, which has door ridges 1 to 2, 2 which are oriented vertically on both the left and right sides of the rear surface and are spaced apart from each other by a predetermined distance. is formed, and sashes 3, 3 as door parts are installed at both left and right ends, and inside the outer shell 4 is a filling 5, which will be described later.
is accommodated.

Further, the heat insulating door 1 is configured such that the inside of the outer shell 4 is maintained in a vacuum state through the steps described below, thereby exhibiting a sufficient heat insulating effect.

The heat insulating door 1 is manufactured through the steps shown in FIG. 2, and the manufacturing method will be described below.

That is, in the case of filling the material shown in FIG.
A resin powder A consisting of a powder or granular material, such as a thermoplastic resin, which melts when heated on a nozzle at a predetermined temperature and solidifies after being heated, and a door component. Satsushi 3 and 3 are stored and covered. Incidentally, in this step, if the lower die 6 is given a slight movement, the resin powder A can be housed more densely. In the pressurizing and vacuuming process (see Fig. 2(b)) that follows the monthly charge filling process, [U, lower mold 6
A lower mold 9 is placed on top of the fixed upper mold 7 and a movable mold 8, and the sash 3.3 in the lower mold 6 is fixed by the second mold 7. The resin powder A in the cavity is pressed together by the movable upper mold 8, and the air in the cavity is pumped through the lower mold 6 through a plurality of small ventilation holes 6a (only two are shown in the figure).・C is discharged to the outside, thereby evacuating the inside of the cavity.Cylinder, in this case, the lower mold 6 and the lower mold 9
By evacuating the entire space containing the , the efficiency of evacuating can be increased. In addition, Fig. 2 (b
) The middle 6b is a filter provided in the small hole 6a of the lower mold 6.

After this, the heating step shown in FIG. 2(C) and the heating step shown in FIG.
The cooling steps shown in d) are performed in sequence. In the heating step, the lower mold 6 and the upper mold 9 are heated to melt the surface of the resin powder A inside (the contact area with the lower mold 6 and the upper mold 9), and subsequently (in the cooling step, The lower mold 6 and the upper mold 9 are cooled to solidify the surface of the resin powder A.The surface of the resin powder A, that is, the part that is once melted and then solidified, forms the surface of the resin powder A after each of these steps. The shell 4 is formed, and the unmelted portion of the resin powder A is constituted as the filling 5, thereby forming the heat insulating door 1.
In the heating step, pressure may be continuously applied to the internal resin powder Δ by the movable upper mold 8.

After the cooling process is completed, the mold opening process shown in FIG. 2(e) is performed to take out the heat insulating door 1.
After this step 5, paint is applied to the outer shell 4, etc., if necessary.

According to this embodiment with such a configuration, the following effect can be achieved. That is, the outer shell 4 with a heat insulation of 15'i:1 is placed between the lower mold 6 and the upper mold 9. Since it is formed by melting and solidifying the surface of resin powder A that has been filled and pressed into a predetermined shape, there is no need to use an outer plate or a molded inner plate, reducing the number of parts. At the same time, it is possible to reduce manufacturing and assembly man-hours.
Since a vacuum insulation layer is formed inside the outer shell 4, the insulation performance is improved compared to conventional foam filling with urethane resin.
to Furthermore, since the sash 3 is embedded during molding of the heat insulating door 1, the heat insulating door 1 can be obtained as a structural body, and the number of assembly steps can be reduced. In the above embodiments, metal such as aluminum may be vapor-deposited on the surface of the outer shell 4 as necessary, or the surface of the vapor-deposited film may be further coated with another material to further improve its heat insulating properties. You can also do it. In addition, although the sash 3 is embedded in the heat insulating door 1, resin powders A and Jζ such as the handle fixing tool, the bracket 1 to the fixing tool, the handle, and the door face plate also have a high softening point and cannot be heated easily. It is also possible to embed parts that can withstand it.

However, the present invention is not limited to the embodiments described above and shown in the drawings; for example, the powder or granular material constituting the filling material is not limited to thermoplastic resin, but may include hollow bodies of glass, Other materials such as powder or ceramics may also be used (
, the present invention deviates from the gist of J.
- When manufacturing an insulated door with improved insulation performance by forming a vacuum insulation layer inside the outer shell, an outer M7SfI can be formed without using an outer panel or an inner panel, and its valve parts It is possible to reduce the number of points and the number of manufacturing man-hours and assembly man-hours associated with this, thereby achieving an excellent effect of reducing costs.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the present invention, with Figure 1 being a perspective view showing a partially sectional view of a heat-insulating door, and Figure 2 being a cross-sectional view showing the manufacturing process of the heat-insulating door. It is. In the drawings, 1 is a heat insulating door, 4 is an outer shell, 5 is a filling, 6 is a lower mold, and 9 is a second mold.

Claims (1)

[Claims] 1. Providing a mold having a cavity shaped to correspond to the external shape of the heat insulating door, and storing a filling made of powder or granules that melts when heated to a predetermined temperature or higher in the mold; a step of evacuating the inside of the mold; and a step of heating and melting the contact surface of the filling material with the mold, and forming an outer shell portion on the contact surface by cooling and solidifying the melted portion. A method of manufacturing an insulated door that involves the following steps.