JPS5934831Y2 - Connection structure of resin duct - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a connection structure for resin ducts, and particularly to a connection structure for resin ducts by blow molding and having flanges for connection ends.

As for the connection structure of conventional resin ducts,
For example, as disclosed in Japanese Patent No. 77849, there is one shown in FIGS. 1 and 2.

The resin ducts 1a and Ib in Fig. 1 have the same shape and structure, and flanges 3a and 3b for the connecting ends, which are butted against each other and a sealing material 2 is interposed between them, are made to protrude outside of the ducts 1a and 1b. prepared in good condition.

Moreover, the resin ducts 4a and 4b shown in FIG. I intervene.

However, in such a conventional resin duct connection structure, although the ventilation resistance and noise can be reduced in the case of the ducts 1a and 1b in Fig. 1, the wall thickness of the flanges 3a and 3b during blow molding is larger than that of other ducts. Part 6 a t 5 b
It tends to be thinner and the necessary rigidity cannot be obtained, and in the case of the ducts 4a and 4b shown in Fig. 2, although the necessary and sufficient rigidity can be obtained at the joint between the flanges 5a and 5b, the ventilation resistance is large and noise is likely to be generated. It was something.

The present invention was developed by focusing on the conventional resin duct connection structure, particularly the blow molded resin duct connection structure with an inner flange. The flange of the duct having the same shape and structure is made to bulge outward and the opening cross-sectional area of the seven flange is formed to be approximately equal to the opening cross-sectional area of the duct part, and a sealing material is placed inside the duct part in the bulged part. By butting and joining them, the necessary and sufficient rigidity of the flange joint part can be obtained, similar to a duct with flanges on the inside, and the generation of small ventilation resistance and noise can be achieved as with a duct with 7 flanges on the outside. This provides a connection structure for resin ducts made by small blow molding.

The details of the present invention will be explained below based on FIGS. 3 and 4.

First, to explain the structure, the ducts 8a and 8b of the same shape and structure by blow molding are butted together and have a flange 10a t 1 for the connection end with a sealing material 9 interposed between them.
0b is the duct portion 11a.

The duct 8a is integrally bent in a direction perpendicular to the center line A of the duct 11b, and the duct 8a is provided in the vicinity of the flange bent portion 12at12b of the duct portions 11a and 11b.

8b is rapidly expanded to the outside, and 1
In addition, the opening cross-sectional area SF of the flanges 10a, 10b is approximately equal to the opening cross-sectional area SO of the duct portions 11a, 11b.

The distance t over which the opening cross-sectional area changes within the range where the wall thickness near the flange bent portion 12at12b does not become thin.
This is to make it as short as possible.

Then, the blow molded ducts 8a, 8 with the above contents are made.
b are abutted on the inside of the duct portion 11a>11b of the bulged part of the inner flanges 10a and 10b, and this is also abutted with the sealing material 9 in between,
8a.

8b.

Next, to explain the operation, the center of the fluid flowing from the direction of arrow B, such as air, is located at the duct portion 11a and the flange 10.
Since the cross-sectional areas of the openings of the flange 10b1 and the duct portion 11b are equal, the air flows through the air with almost no ventilation resistance.

On the other hand, the fluid portion near the inner surface of the duct portion 11a is a flange bent portion 12a that bulges outward rapidly.

12b enters the inside and generates a vortex, but of course the degree of vortex is much smaller than that of the conventional inner flange type duct (see Figure 2), and the distance t over which the opening cross-sectional area changes should be kept as short as possible. Therefore, the fluid immediately flows away toward the duct portion 11b along with the central flow of the fluid.

Further, the grooves in which the inner flanges 10atlOb butt each other are joined via the sealing material 9, and the flange 10a is joined at the time of joining.

Since no particular change in shape is caused in the vicinity of 10b1 and the flange bent portions 12a and 12b, the fluid flow is as described above, and therefore, the generation of noise due to vortex flow is slight.

FIG. 4 shows an inner flange type duct) 4a, 4bs, an outer flange type duct lla, 1b, and a duct 8a according to the present invention.

The graph shows the measured values of the ventilation resistance of each of the ducts 8b in comparison, and the ventilation resistance of the ducts 8a and 8b according to the present invention is that of the outer flange type duct Ha.

It can be seen that it is almost the same as 1b.

As explained above, according to the present invention, the structure is such that the vicinity of the flange bent portion of the duct portion bulges outward, and the opening cross-sectional area of the flange is formed to be approximately equal to the opening cross-sectional area of the duct portion, The flanges of ducts of the same shape and structure are joined by butting each other with a sealing material inside the duct part of the bulged part, so even though it has a flange for the connecting end on the inside, ,
There are many advantages such as lower ventilation resistance, less noise generation, and the ability to obtain necessary and sufficient rigidity at the flange joint portion.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional blow-molded duct, FIG. 2 is a cross-sectional view of another conventional blow-molded duct, and FIG. 3 is a cross-sectional view showing a connection structure of a blow-molded duct according to the present invention.
FIG. 4 is a graph showing the ventilation resistance of the conventional blow molded duct and the blow molded duct according to the present invention. 8a, 8b...Blow molded duct, 10a. 10b...flange, 11a, 11b...
...Duct part, 12a, 12b... Flange bent part, SF... Flange opening cross-sectional area, SO.
...Opening cross-sectional area of the duct.

Claims (1)

[Claims for Utility Model Registration] In a resin duct connection structure in which a flange for a connecting end is integrally bent in a direction perpendicular to the center line of the duct part, the flange bent part of the duct part The vicinity of the bulge is made to bulge outward, and the opening cross-sectional area of the seven flange is formed to be approximately equal to the opening cross-sectional area of the duct part, and a sealing material of the same shape and structure is formed inside the duct part in the bulged part. A resin duct connection structure characterized by joining by butting the flanges of the ducts together.