JPH0560729B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing an inner lid packing for a rice cooker or a warmer, and more particularly, the present invention relates to a method for manufacturing an inner lid packing for a rice cooker or a warmer (for a rice cooker or a warmer). The present invention relates to a method of manufacturing an inner lid packing for a rice cooker or a heat insulator, which can be formed at low cost.

Recently, there is a tendency to improve the quality of rice cookers that only cook rice, rice cookers that have a heat insulator, and warmers that only keep warm, by adding microcomputer control, etc., but it is not possible to significantly increase the cost (increase in selling price). There is a tendency that There is a demand to reduce the cost of the various parts that make up these parts without degrading their quality, and among these demands, there is a demand to form the gasket used for the inner lid at low cost. The gasket used here is designed to prevent the steam generated from the inner pot from leaking out to the outside in heat insulators such as rice cookers and thermal jars, and to prevent the steam generated from the inner pot from entering the inner lid. It has the following two functions. The reason to prevent steam from entering the inner lid is that the inner lid has a built-in heater, temperature sensor, etc., and moisture can cause short circuits at the heater terminals, sensor malfunctions, etc. This is because there is a risk of causing It also serves as a heat insulator for pots, lunch jars, coolers, and other heat insulators.

(Prior art) Hereinafter, the prior art will be specifically explained using drawings.

Figures 6 to 10 are diagrams explaining a conventional method of manufacturing an inner lid packing for a rice cooker. Figure 6 is a schematic diagram showing the structure of a conventional rice cooker, and Figure 7 is a press metal plate of a conventional example. A diagram showing the state of the mold when pressed. Figure 8 is a schematic diagram showing the state in which the dispensed silicone rubber of the conventional example is set in the mold. Figure 9 is a diagram showing the inner lid packing of the conventional example taken out from the mold. FIG. 10 is a diagram illustrating a conventional process for removing burrs from an inner lid packing.

In these figures, 31 is an inner lid, 32 is an inner lid heater, 33 is a screw, 34 is an inner lid gasket made of silicone rubber, 35 is a steam hole for releasing steam, 36 is an inner pot, and 37 is a body heater. , 38 is a sheathed heater, 39 is an outer frame, 40 is an outer lid, 41 is an upper heating plate, 42 is a lower heating plate, 43 is an upper mold, 44
45 is a middle mold, 45 is a lower mold, 46 is a burr groove, 47 is silicone rubber, 48 is a mold consisting of an upper hot plate 41 and an upper mold 43, 49 is a middle mold 44 and a lower mold 45 The mold, 50, has burrs.

Note that the direction of the X mark shown in FIG. 6 indicates the opening/closing direction of the outer cover 40. The press mold is composed of an upper mold 43, a middle mold 44, and a lower mold 45.

Next, a method of manufacturing the inner lid packing 34 will be explained.

The manufacturing process consists of a rubber kneading process → a dispensing process,
→ Press molding (also called compression molding) process → Deburring process → Aging process (secondary vulcanization process). Specifically, as shown in FIG. 8, the silicone rubber 47, which has been kneaded and dispensed to a predetermined amount, is placed in molds 49 (middle mold 44 and lower mold 4).
5) Set it in the predetermined position. This dispensing is normally carried out according to the number of inner lid packings 34 of the press mold (here, four as shown in FIG. 8). Thereafter, the upper mold 43 attached to the upper hot plate 41 and the lower mold 45 and middle mold 44 attached to the lower hot plate 42 are pressed together by the force of the hydraulic cylinder of the press machine as shown in FIG. , compress firmly and press mold. At this time, the silicone rubber is vulcanized by heating and pressurizing for a predetermined period of time (usually 3 to 5 minutes). Then, as the cylinder descends, the mold 48 (upper mold 43 and upper hot plate 41) and mold 49 (middle mold 44 and lower mold 45) are separated.

Next, the inner lid packing 34 made of vulcanized silicone rubber is taken out from the middle mold 44 and the lower mold 45. At this time, the middle mold 44 and the lower mold 45 are separated, and this is to prevent the silicone rubber at part A shown in FIG. 9 from being torn when removed from the mold. This is because if the mold 44 and the lower mold 45 are not integrated, they are likely to be torn apart when removed from the mold. Note that after the molds 48 and 49 are separated, the molds may be configured to prevent the silicone rubber from being torn when the middle mold 44 moves slightly upward. .

Next, the removed inner lid packing 34 is deburred. In the case of press molding, if the filling amount of silicone rubber is small, the product will likely be defective due to lack of rubber, etc., so generally the weight of the product is reduced by 100%.
Then, it will divide from 105 to 110. Then, the excess silicone rubber becomes a burr 50 as shown in part B shown in FIG. Therefore, specifically, the burrs 50 are removed along the circumference of the inner cover gasket 34, so the burrs are removed.

Then, by aging, the inner lid packing 34 as a product is completed. This aging is done to eliminate the unique odor of silicone rubber.

In addition, although the above-mentioned prior art describes an inner lid packing for a rice cooker, it can also be applied to an inner lid packing for a heat insulator that only maintains heat.

(Problem to be Solved by the Invention) However, in the conventional manufacturing method of the inner lid packing for a rice cooker or a heat insulator, press molding usually requires about 5 to 10 minutes per cycle. However, there was a problem in that equipment costs and personnel costs increased as production volume increased. Specifically, each press molding machine usually has one worker working on it, and if you try to increase production volume, the mold costs and labor costs will increase, especially among the equipment costs. . Furthermore, as mold costs increase, depreciation costs also increase.
Moreover, when the cross-sectional shape of the inner lid packing 34 is the same,
Since the size of the circumference of the inner lid gasket 34 changes depending on the capacity of the rice cooker, a press mold appropriately matched to the size of the circumference is required each time.

Therefore, the present invention provides an inner lid packing for a rice cooker or a heat insulator that can reduce labor costs and mold costs, form an inner lid packing at low cost, and increase the degree of freedom in designing the inner lid packing. The purpose is to provide a manufacturing method.

(Means for Solving the Problems) In order to achieve the above-mentioned purpose, the method of manufacturing an inner lid packing for a rice cooker or a warmer according to the present invention uses an extrusion molding machine to form silicone rubber into a shape that functions as an inner lid packing for a rice cooker or a warmer. a step of extrusion molding into a predetermined shape, a step of cutting the extruded silicone rubber into a predetermined length, a step of jointing both ends of the cut silicone rubber, and a step of joining the jointed silicone rubber. The method includes an aging step.

(Function) The present invention is characterized in that silicone rubber is extruded into a predetermined shape using an extrusion molding machine so as to function as an inner lid packing for a rice cooker or a heat insulator, and the extruded silicone rubber is cut into a predetermined length. Thereafter, both ends of the cut silicone rubber are jointed, and the silicone rubber is further aged to form an inner lid packing for a rice cooker or a heat insulator.

Therefore, through final aging, the adhesive strength of the joint surface is increased, improving the reliability of the inner lid packing, and at the same time, it is possible to form the inner lid packing at a low cost by reducing labor and mold costs. In addition, the degree of freedom in designing the inner lid packing can be increased.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. It should be noted that, as a matter of course, the following example shows an example of the present invention, and the present invention is not limited only to this example.

1 to 5 are diagrams for explaining an embodiment of the method for manufacturing an inner lid packing for a rice cooker according to the present invention, and FIG. 1 is a schematic diagram showing the structure of a rice cooker according to an embodiment, and FIG. The figure is a cross-sectional view showing the structure of the joint mold of one example, Figure 3 is a diagram explaining the joint process of one example, and Figures 4 a and b are silicone immediately after extrusion and after aging of one example. FIGS. 5a and 5b are diagrams illustrating changes in the length of the rubber, and are diagrams illustrating the effects of one embodiment.

In these figures, the same reference numerals as in FIGS. 6 to 10 indicate the same or corresponding parts, 1 is an inner lid packing made of silicone rubber and corresponds to the inner lid packing according to the present invention, and 2 is a hollow part. be. 3 is silicone rubber, and 4 is a joint surface. The joint mold 7 is composed of an upper mold 5 and a lower mold 6.

Next, a method of manufacturing the inner lid packing 1 will be explained.

The manufacturing process is as follows: rubber kneading process → extrusion molding process → aging process → cutting process → jointing process → aging process. Specifically, a silicone rubber suitably compounded through a rubber kneading process is molded into a hollow 2 as shown in FIG. It is extruded into a long piece in the shape that it has. The extruded silicone rubber is then aged. The aging process is performed to improve the physical properties (tensile strength, elasticity, etc.) of the silicone rubber, to bring it into a completely contracted state, and to remove the odor characteristic of silicone rubber.
The reason why the inner lid packing 1 is completely contracted is to make the inner diameter of the inner lid packing 1 as a product uniform.

Next, the extruded and aged silicone rubber is cut to a predetermined length so that it can be set along the inner lid 31.

Next, an adhesive made of, for example, one-component thermosetting liquid silicone rubber is applied to both end surfaces, that is, joint surfaces 4, of the silicone rubber 3 cut to a predetermined length as shown in FIG. The joint portion M of the inner lid packing 1 shown in FIG. 3 is set in the joint mold 7 shown, and jointing is performed. Specifically, after setting the joint part M of the inner lid packing 1 into the lower mold 6 constituting the joint mold 7 and placing the upper mold 5 thereon, the lower mold 6 and the upper mold are separated using an air press machine or the like. Compress 5. At this time, the lower mold 6 and the upper mold 5 are heated to a predetermined temperature in advance,
The joint can be achieved by heating and curing the adhesive adhered to the joint surface 4 using the heat of the mold.

Then, in order to further increase the adhesive strength of the joint surface 4 of the inner lid packing 1, aging is finally performed again to complete the inner lid packing 1 as a product.

That is, in the above embodiment, the inner lid packing 1 is formed by using the manufacturing method of extrusion molding, jointing, and final aging, so that the adhesive strength of the joint surface 4 is increased and the reliability of the inner lid packing 1 is increased. In addition to improving sexual
The inner lid packing 1 can be formed at low cost by suppressing labor costs and mold costs, and the inner lid packing 1 can be formed at low cost.
The degree of freedom in designing can be increased. Specifically, the mold cost is about 1/10 of that of conventional molds, including the extrusion mold and joint mold 7, so it is easy to change the shape and design of the inner lid packing 1. If the cross-sectional shape of the inner lid gasket is the same, but the circumference size of the inner lid gasket changes depending on the capacity of the rice cooker, in the conventional method, a different press mold is required each time, but in the above example, extrusion molding is used. After that, it is cut to a predetermined length as appropriate, so there is no need to create a new mold, and mold costs can be saved.

In addition, when performing jointing, the joint can be performed by simply applying a small amount of adhesive to the joint surface 4, which has the advantage that almost no burrs are generated unlike conventional methods, and there is no need to remove burrs. There is. Furthermore, since the adhesive strength of the joint surface 4 is increased by finally aging again, the reliability of the inner lid packing 1 can be improved.

Furthermore, as shown in FIGS. 5a and 5b, in the conventional method, only the inner lid packing 34 having a shape without a hollow space as shown in FIG. 5a can be formed, but according to the above embodiment, The inner lid packing 34 shown in FIG. 5a, which has a shape without a hollow space, or the inner lid packing 1 shown in FIG. 5b, which has a hollow shape 2, can be formed, increasing the degree of freedom in designing the inner lid packing. be able to. The inner lid packing 1 having the hollow 2 has an advantage in that the sealing performance against the inner pot 36 is improved compared to the inner lid packing 34 without a hollow. The sealing performance is improved by changing the hollow 2 and by its repulsive force.

In addition, although the above-mentioned example explained the manufacturing method of the inner lid packing for a rice cooker, the present invention is not limited to this, but can also be applied to a manufacturing method for the inner lid packing for a heat insulating device such as a heating jar, a lunch jar, or an air conditioner. can also be applied.

In the above embodiment, the manufacturing process of the inner lid packing 1 is described as a preferable embodiment in which the process of manufacturing the inner lid packing 1 goes through the following steps: rubber kneading process → extrusion molding process → aging process → cutting process → jointing process → aging process. This is not limited to this, but if the dimensional tolerance of the inner diameter h of the inner lid packing 1 after jointing as shown in Fig. 3 is rough, the steps are as follows: rubber kneading process → extrusion molding process → cutting process → jointing process → aging process. It is also possible to go through a process like this. This is because the shrinkage of silicone rubber is not completely constant and varies, so as shown in Figure 4, the ratio of the length of silicone rubber immediately after extrusion l ₁ to the length of silicone rubber after aging l ₂ is This is because ₁ /l ₂ is not constant, which may cause variations in the inner diameter h of the inner lid packing 1 after jointing.

(Effects) According to the present invention, the reliability of the inner lid packing is improved by increasing the adhesive strength of the joint surface through final aging, and the inner lid packing is formed at low cost by suppressing labor costs and mold costs. This has the effect of increasing the degree of freedom in designing the inner lid packing.

[Brief explanation of the drawing]

1 to 5 are diagrams for explaining an embodiment of the method for manufacturing an inner lid packing for a rice cooker according to the present invention, and FIG. 1 is a schematic diagram showing the structure of a rice cooker according to an embodiment, and FIG. The figure is a sectional view showing the structure of the joint mold of one example, Figure 3 is a diagram explaining the joint process of one example, and Figure 4 is the length of the silicone rubber immediately after extrusion and after aging of one example. FIG. 5 is a diagram explaining the effect of one embodiment. FIGS. 6 to 10 are diagrams explaining a conventional method of manufacturing an inner lid packing for a rice cooker. A schematic diagram showing the configuration of a conventional rice cooker; FIG. 7 is a diagram showing the state of a conventional press mold when pressed;
Fig. 8 is a schematic diagram showing a conventional example in which dispensed silicone rubber is set in a mold, Fig. 9 is a diagram illustrating taking out the inner lid packing of a conventional example from the mold, and Fig. 10 is a conventional example. It is a figure explaining the burr removal of the inner lid packing of an example. 1...Inner lid packing, 2...Hollow, 3...Silicone rubber, 4...Joint surface, 5...Upper mold, 6...Lower mold, 7...Joint mold, 31
... Inner lid, 32 ... Inner lid heater, 33 ... Screw fastening, 35 ... Steam hole, 36 ... Inner pot, 37 ... Trunk heater, 38 ... Sheathed heater, 39 ... Outer frame,
40...Outer lid.

Claims (1)

[Claims] 1. Silicone rubber is made using an extrusion molding machine.
A step of extrusion molding into a predetermined shape so as to function as an inner lid gasket for a rice cooker or a warmer; a step of cutting the extruded silicone rubber into a predetermined length; and a step of cutting both ends of the cut silicone rubber into a predetermined length. A method for manufacturing an inner lid gasket for a rice cooker or a heat insulator, comprising: a step of jointing; and a step of aging the jointed silicone rubber.