Duct, duct fitting structure, and duct manufacturing method

Abstract

To improve the strength of an opening part of a duct.SOLUTION: A duct 10 includes a bifurcated branch duct 12 at a rear end part. At the end part of the branch duct 12 that has openings 60, 69, a linear protrusion 70 extending along the opening edge and projecting to the inner side is formed on upper opposing walls 31A, 31B and on lower opposing walls 32A, 32B. The linear protrusion 70 is not formed on right-side opposing walls 33A, 33B and on the left-side opposing walls 34A, 34B.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a duct-to-duct fitting structure and a duct manufacturing method. [Background technology]

[0002] BACKGROUND ART Ducts with open ends are known in the art (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2954584 (Paragraph

[0010] ) Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of duct, it is required to improve the strength of the opening portion. [Means for solving the problem]

[0005] A first aspect of the present invention, which has been made to solve the above problems, is a duct that has a protrusion that extends along the edge of the opening and protrudes inward at the opposing end that has an opening and faces the duct wall. [Effects of the Invention]

[0006] According to the first aspect of the invention, the protrusion is provided along the edge of the opening, thereby improving the strength of the end portion having the opening. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a top view of a duct according to an embodiment; [Figure 2] Top view of the vehicle to which the duct will be installed [Figure 3] Perspective view of the duct [Figure 4] Side view of the duct [Figure 5] Enlarged view of the duct opening [Figure 6] Side cross section of duct [Figure 7] Side view of duct intermediate product [Figure 8] Top view of duct intermediate product [Figure 9] Cross-sectional view showing the manufacturing process of a duct intermediate product [Figure 10] Top view showing the manufacturing process of the duct intermediate product [Figure 11] Vertical cross-sectional view showing the manufacturing process of a duct intermediate product [Figure 12] Cross-sectional view showing the manufacturing process of a duct intermediate product [Figure 13] Vertical cross-sectional view showing the manufacturing process of a duct intermediate product [Figure 14] A perspective view of a duct with an elastic member disposed at the open end [Figure 15] Cross-sectional view of the connecting duct and the duct that is to be mated and connected [Figure 16] Vertical cross-sectional view showing the manufacturing process of a duct intermediate product DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] A duct 10 according to one embodiment of the present disclosure will be described with reference to FIGS. 1 to 16. As shown in FIG. 1, the duct 10 (corresponding to the "duct" in the claims) of this embodiment is a blow-molded product, has a substantially linear shape overall, and is bifurcated at one end. The bifurcated portions of the duct 10 are a first branch duct portion 12A and a second branch duct portion 12B (corresponding to the "pair of branch portions" in the claims), and the remaining portion is a main duct portion 11. An attachment portion 13 (corresponding to the "attachment portion" in the claims) for attaching the duct 10 to a vehicle is provided between the first branch duct portion 12A and the second branch duct portion 12B. When the first branch duct portion 12A and the second branch duct portion 12B are not distinguished from each other, they are simply referred to as the branch duct portion 12.

[0009] The duct 10 is used, for example, as an air conditioning duct for a vehicle 100. Specifically, as shown in Fig. 2, the front end of the duct 10 is connected to an air conditioning unit 102 in an engine room, the main duct portion 11 extends rearward along a center console 103, and the branch duct portion 12 is fitted into a pair of connecting ducts 90. The connecting ducts 90 are each connected to an air outlet device (not shown). The mounting portion 13 is fixed to a floor 101 of the vehicle 100.

[0010] Hereinafter, the left side of the duct 10 when viewed from behind (the left side in FIG. 1) will be referred to simply as the "left side," and the opposite side (the right side in FIG. 1) will be referred to simply as the "right side," and each part of the duct 10 will be described in detail.

[0011] The main duct portion 11 has a generally rectangular cross section that is flat in the vertical direction, extends longitudinally in the front-rear direction, and is provided at its front end with an opening 11K that opens obliquely upward.

[0012] As shown in FIGS. 1 and 3, the first branch duct portion 12A extends rearward from the left side of the rear end of the main duct portion 11 and has a vertically elongated rectangular cross section. Specifically, the first branch duct portion 12A includes an upper opposing wall 31A and a lower opposing wall 32A (corresponding to "opposing portions" and "second opposing walls" in the claims) that face each other in the vertical direction, and a left opposing wall 33A and a right opposing wall 34A (corresponding to "first opposing walls" in the claims) that face each other in the left-right direction. The upper and lower opposing walls 31A and 32A are narrower in width than the right and left opposing walls 33A and 34A. The corners between adjacent opposing walls 31A-34A are curved. The rear end of the first branch duct portion 12A is provided with a first opening 60 (corresponding to "opening" in the claims) that opens rearward. The first opening 60 is longer in the vertical direction and shorter in the left-right direction than the cross section of the rear end of the main duct portion 11.

[0013] The upper opposing wall 31A is provided with a first inclined wall 61 formed by gently inclining the upper wall 11A of the rear end of the main duct portion 11 upward, and a first flat upper wall 62 extending from the rear end of the first inclined wall 61 substantially parallel to the upper wall 11A of the main duct portion 11. The lower opposing wall 32A is parallel to the first flat upper wall 62 and extends generally flat from the lower wall 11B (see FIG. 4) of the main duct portion 11.

[0014] 1 and 3, the left facing wall 33A is formed by extending the left wall 11C of the main duct portion 11. The right facing wall 34A extends parallel to the left facing wall 33A, and a first curved wall 63 is provided in the front portion of the right facing wall 34A, the first curved wall 63 being curved so that the inside of the curved surface faces right rearward.

[0015] The second branch duct portion 12B has a second duct front portion 12B1 extending diagonally to the right from the right side of the rear end of the main duct portion 11, and a second duct rear portion 12B2 bending rearward from the front portion 12B1 and extending substantially parallel to the first branch duct portion 12A. The cross-sectional shape of the second branch duct portion 12B is a vertically long rectangle, similar to the first branch duct portion 12A.

[0016] The second branch duct portion 12B also has an upper opposing wall 31B and a lower opposing wall 32B (corresponding to "opposing portions" and "second opposing walls" in the claims) that face each other in the vertical direction, and a left opposing wall 33B and a right opposing wall 34B (corresponding to "first opposing walls" in the claims) that face each other in the left and right direction. The upper and lower opposing walls 31B, 32B are narrower in width than the right and left opposing walls 33B, 34B. The corners of adjacent opposing walls 31B-34B are curved. The rear end of the second branch duct portion 12B is provided with a second opening 69 (corresponding to "opening" in the claims) that opens rearward. This second opening 69 has substantially the same shape as the first opening 60 of the first branch duct portion 12A.

[0017] In the second branch duct portion 12B, the upper opposing wall 31B of the second duct front portion 12B1 is located lower than the upper opposing wall 31B of the second duct rear portion 12B2, and the upper opposing wall 31B is provided with a second inclined wall 64 that slopes upward toward the rear at the connecting portion between the second duct front portion 12B1 and the second duct rear portion 12B2. Furthermore, the upper opposing wall 31B of the second duct rear portion 12B2 is a second flat upper wall 65 that extends generally flat. The lower opposing wall 32B extends generally substantially flat from the bottom wall 11B of the main duct portion 11 (see FIG. 4).

[0018] The left facing wall 33B includes a second left extending wall 66 that continues from the first curved wall 63 of the first branch duct portion 12A and extends rearward to the right, and a second left flat wall 67 that curves rearward from there and extends parallel to the right facing wall 34A of the first branch duct portion 12A. The right facing wall 34B bends rightward from the rear end of the right wall 11D of the main duct portion 11 and has a shape that follows the left facing wall 33B, and includes a second right extending wall 34B1 and a second right flat wall 34B2.

[0019] 1 and 3, the mounting portion 13 is disposed below and between the first curved wall 63 and the second left extending wall 66. The mounting portion 13 has a mounting bulge 13A that bulges out laterally along the first curved wall 63 and the second left extending wall 66, a hanging mounting wall 13B that hangs down from the edge of the mounting bulge 13A, and a lower mounting wall 13C that extends rearward and to the right from the lower end of the hanging mounting wall 13B. A through hole 13D is formed in the lower mounting wall 13C for screwing the duct 10 to the floor 101 of the vehicle.

[0020] In this embodiment, a parting line 47 (see FIG. 4 ) formed during blow molding extends along the vertical center of the outer surface of the duct 10 (corresponding to the “parting line” in the claims). The parting line 47 in the branch duct portion 12 is located approximately in the vertical center of the branch duct portion 12, as shown in FIG. 5 (FIG. 5 shows the first branch duct portion 12A). The parting line 47 extends horizontally from the right edge of the first opening 60 of the first branch duct portion 12A, then slopes downward to connect with the lower left end of the mounting bulge 13A. Similarly, the parting line 47 extends horizontally from the left edge of the second opening 69 of the second branch duct portion 12B, then slopes downward to connect with the lower right end of the mounting bulge 13A.

[0021] In the duct 10 of this embodiment, a linear protrusion 70 (corresponding to the "protrusion" in the claims) is formed on the inside of the rear end of the branch duct portion 12. Hereinafter, the linear protrusion 70 will be described using the one provided in the first branch duct portion 12A as an example.

[0022] As shown in Figures 3 and 6, the linear protrusion 70 is disposed in the first branch duct portion 12A at a position near the first opening 60 between the upper opposing wall 31A and the lower opposing wall 32A. The linear protrusion 70 forms a protrusion that protrudes inward from the upper and lower opposing walls 31A, 32A and extends linearly along the opening edge of the first opening 60. The vertical cross section of the linear protrusion is semicircular. Furthermore, the linear protrusion 70 is not formed on the left opposing wall 33A or the right opposing wall 34A, and both longitudinal ends of a linear recess 71 (corresponding to a "groove" in the claims) formed on the back side of the linear protrusion 70 are open in the left-right direction.

[0023] The width of the linear protrusions 70 is preferably 1 / 10 to 2 / 5 of the equivalent diameter of the openings 60, 69, and the protrusion amount of the linear protrusions 70 is preferably 1 / 20 to 1 / 5 of the equivalent diameter of the openings 60, 69. The distance from the rear edge of the linear protrusions 70 to the opening edges of the openings 60, 69 is the width of the sealing material, and is therefore preferably 5 mm to 20 mm.

[0024] Next, a method for manufacturing the duct 10 will be described. The duct 10 is manufactured by blow-molding a duct intermediate 51 (see FIGS. 7 and 8), which corresponds to the "duct intermediate product" in the claims, and which has a disposal bag 50 (corresponding to the "bag portion" in the claims) attached to the rear end of the branch duct portion 12 of the duct 10, and then cutting off the disposal bag 50. This will be described in detail below.

[0025] First, the manufacture of the duct intermediate 51 will be described. The duct intermediate 51 is manufactured by blow molding using a mold 80. As shown in Fig. 9, the mold 80 is divided into a left mold part 80A and a right mold part 80B, and has a cavity 81 formed therein for forming the duct intermediate 51. As shown in Fig. 10, the cavity 81 has a main cavity portion 81A extending in a substantially straight line, and a pair of branch cavities 81B branching into two from the rear end of the main cavity portion 81A. The rear ends of the pair of branch cavities 81B form waste bag forming portions 84 (see Fig. 11) for forming the waste bags 50.

[0026] First, as shown in Figures 9 and 11, a cylindrical parison 82 made of molten resin is placed between a left mold 80A and a right mold 80B. Then, as shown in Figure 12, the mold 80 is closed, and the walls of the parison 82 are brought into close contact with each other outside the cavity 81, forming a parting line 47, and a void is created within the parison 82 inside the cavity 81. Air is blown into the parison 82 from the top or bottom end, causing the parison 82 to expand within the cavity 81.

[0027] The parison 82 into which air has been blown is cooled and solidified starting from the point where it contacts the mold 80. When the outer periphery of the expanded parison 82 contacts the mold 80 without any gaps, the duct intermediate 51 is formed (see FIG. 13).

[0028] Here, the left and right molds 80A, 80B are each provided with a mold protrusion 83 that protrudes into the branch cavity 81B and forms the linear protrusion 70. Furthermore, the left and right molds 80A, 80B are also provided with a mold protrusion 83 in the disposal bag forming section 84. The mold protrusion 83 in the disposal bag forming section 84 extends parallel to the mold protrusion 83 for the linear protrusion 70. As a result, as shown in Figures 7 and 8, the linear protrusion 70 of the duct 10 and the bag-side linear protrusion 72 of the disposal bag 50 are formed in parallel on the insides of the upper and lower opposing walls 31A, 32A of the duct intermediate product 51.

[0029] Next, a blade is applied to the cutting point 86 (corresponding to the "cutting point" in the claims) between the linear convex portion 70 and the bag side linear convex portion 72 of the duct intermediate product 51 to cut the disposal bag 50, thereby producing the duct 10.

[0030] The duct 10 is connected to the connecting duct 90 (corresponding to "another duct" in the claims) as follows: That is, as shown in Fig. 14, a strip-shaped elastic member 85 (e.g., a urethane foam seal) corresponding to the "elastic member" in the claims is wrapped around the branch duct portion 12 of the duct 10 on the opening 60, 69 side (corresponding to the "fixing portion" in the claims) relative to the linear convex portion 70 (see Fig. 14), and this elastic member 85 is inserted into the opening of the connecting duct 90 so as to be compressed, thereby fitting and connecting the branch duct portion 12 and the connecting duct 90 (see Fig. 15).

[0031] Next, the effects of the duct 10 will be described. As described above, in the duct 10, the connecting duct 90 is fitted and connected to the outside of the rear end portion (the end portion having the openings 60, 69) of the branch duct portion 12. At this time, there is a concern that the branch duct portion 12 will bend inward, reducing the airtightness between the branch duct portion 12 and the connecting duct 90. In particular, there is a concern that when the disposal bag 50 is cut from the duct intermediate product 51, a blade will be pressed against it from the outside, causing the branch duct portion 12 to bend inward in the vertical direction.

[0032] In contrast, in the duct 10 of this embodiment, a linear protrusion 70 extending along the opening edge is formed at the rear end of the branch duct portion 12, which increases the strength of the rear end of the branch duct portion 12 and prevents the branch duct portion 12 from bending inward. Moreover, since the linear protrusion 70 and the bag-side linear protrusion 72 are arranged on both sides of the cut portion in the duct intermediate product 51, the branch duct portion 12 is further prevented from bending inward when the disposal bag 50 is cut.

[0033] Additionally, in order to strengthen the end of the duct 10, it is possible to make the linear protrusions protrude outward, but in this case, there is a concern that the plate thickness around the linear protrusions will be reduced, weakening the rigidity. In contrast, in this embodiment, the linear protrusions 70 protrude inward, so a greater plate thickness can be ensured than if the linear protrusions protruded outward, preventing a decrease in rigidity.

[0034] Furthermore, it is believed that by providing the linear protrusions 70 that protrude inward, the plate thickness of the rear end portion of the branch duct portion 12 can be made larger than when the linear protrusions 70 are not provided.

[0035] More specifically, the portion of parison 82 into which air has been blown is first cooled and solidified at the portion sandwiched between left mold 80A and lower mold 80, forming parting line 47, and then, starting from the side closest to this, it comes into contact with the inside of mold 80 and is cooled. Therefore, the amount of resin in expanding parison 82 decreases as it moves away from parting line 47, and it may not be possible to ensure a sufficient plate thickness at locations away from parting line 47.

[0036] In contrast, by providing mold protrusions 83 at the forming portions of the opposing walls that face away from the parting surface of the mold 80 as in this embodiment, the resin of the expanding parison 82 first comes into contact with the mold protrusions 83 and solidifies (see FIG. 16 ), preventing the vicinity of the linear protrusions 70 (i.e., the rear end of the branch duct portion 12) from becoming thin. Moreover, since the mold protrusions 83 are also provided in the disposal bag forming portion 84, the portion of the duct intermediate product 51 sandwiched between the linear protrusions 70 and the bag-side linear protrusions 72 is less likely to become thin, thereby further increasing strength. Furthermore, the increased strength of the portion of the duct intermediate product 51 sandwiched between the linear protrusions 70 and the bag-side linear protrusions 72, i.e., the cut portion, also prevents deformation during cutting.

[0037] It is also conceivable to provide linear protrusions 70 continuously along all four sides of branch duct portion 12, but in that case, it is believed that it would be difficult for the resin to reach the corners adjacent to linear protrusions 70, resulting in an extreme decrease in strength of those portions. Therefore, in this embodiment, linear protrusions 70 are provided on the upper opposing walls 31A, 31B and the lower opposing walls 32B, 32B, which are far from parting line 47, while linear protrusions 70 are not provided on the left opposing walls 33A, 33B and right opposing walls 34A, 34B, which have parting line 47 (i.e., which have relatively high rigidity). This is believed to effectively strengthen the rear end portion of branch duct portion 12 without creating extremely weak rigidity portions.

[0038] Furthermore, by making the cross-sectional shape of the linear protrusion 70 arc-shaped, the thickness of the linear protrusion 70 is stabilized, and the rigidity of the linear protrusion 70 is maintained.

[0039] [Other embodiments] (1) In the above embodiment, the cross-sectional shape of the openings 60, 69 is rectangular, but it may be circular or square. Also, the cross-sectional shape of the main duct portion 11 may be circular or square.

[0040] (2) In the above embodiment, the linear protrusions 70 are provided on the branch duct portion 12, which is formed by bifurcating the rear end of the duct 10. However, the linear protrusions 70 may be provided on the end of a duct that extends linearly without branching. Also, the rear end of the duct 10 may be branched into three or more branch duct portions 12.

[0041] (3) In the above embodiment, the vertical step shape of the linear protrusion 70 is an arc shape, but it may be a substantially triangular or rectangular shape.

[0042] (4) In the above embodiment, both longitudinal ends of the linear recess 71 formed on the rear side of the linear protrusion 70 are open in the left-right direction, but they may be closed.

[0043] (5) In addition, in the above embodiment, the linear convex portion 70 is formed on both the disposal bag 50 and near the end of the branch duct portion 12, but it may be formed on only one of them.

[0044] (6) The linear protrusions 70 may be provided on only one of the upper opposing walls 31A, 31B and the lower opposing walls 31B, 32B. In this case, providing the linear protrusions 70 on the side against which the blade is pressed when cutting the disposal bag 50 can prevent deformation of the openings 60, 69.

[0045] (7) The linear protrusion 70 may extend over the entire circumferential direction.

[0046] (8) In the above embodiment, the mounting portion 13 is formed between the branch duct portions 12, but it may be formed anywhere, such as on the outer edge of the duct 10. Also, although the mounting portion 13 is configured to be integrally molded with the duct 10, it may be formed separately.

[0047] (9) In the above embodiment, the end of the branch duct portion 12 having the opening is configured to fit inside the connecting duct 90, but it may be configured to fit outside. In this case, it is thought that the linear protrusion 70 abuts against the outer surface of the connecting duct 90, thereby improving the sealing performance.

[0048] (10) In the above embodiment, the duct 10 is used as an air conditioning duct for a vehicle, but it may be used anywhere, such as for indoor air conditioning.

[0049] <Additional Notes> The following describes the features of the inventions extracted from the above embodiments, while indicating, as necessary, their effects, etc. Note that, for ease of understanding, the following will appropriately indicate corresponding configurations in the above embodiments in parentheses, etc. However, the present invention is not limited to the specific configurations indicated in parentheses, etc.

[0050] [Feature A1] In the duct, A duct having a protrusion that extends along the edge of the opening and protrudes inward at the end facing the duct wall, the protrusion having an opening.

[0051] According to feature A1, the protrusion is provided along the edge of the opening, thereby improving the strength of the end portion having the opening.

[0052] [Feature A2] The end portion having the opening has a rectangular cross section and includes a pair of first opposing walls and a pair of second opposing walls, The pair of first opposing walls each have a parting line, 2. The duct according to claim 1, wherein the protrusion is disposed on the pair of second opposing walls that serve as the opposing portions.

[0053] The cross-sectional shape of the end portion having the opening may be circular or rectangular as in Feature A2. In the latter case, by providing a protrusion on the second opposing wall away from the parting line as in Feature A2, it is possible to reinforce the area where rigidity is likely to be low.

[0054] [Feature A3] 3. The duct according to claim 2, wherein the pair of first opposing walls does not include a protrusion that extends along an edge of the opening and protrudes inward.

[0055] If protrusions are provided on both the first opposing wall and the second opposing wall, there is a concern that the resin near the protrusions at the corners between the first opposing wall and the second opposing wall will become thin, but this is prevented by feature A3.

[0056] [Features A4] A duct as claimed in any one of claims 1 to 3, wherein the outside of the duct corresponding to the protrusion is provided with a groove corresponding to the shape of the protrusion, and both ends of the groove are open in the longitudinal direction.

[0057] The grooves corresponding to the shape of the protrusions arranged on the outside of the duct may have closed ends in the longitudinal direction, or may be open as in feature A4.

[0058] [Feature A5] the end portion having the opening forms a fitting portion that is fitted into the inside of another duct, A duct as claimed in any one of claims 1 to 4, wherein the outer surface of the end portion having the opening is formed as a fixing portion on the opening side of the protrusion, to which an elastic member that seals the gap between the other duct is fixed.

[0059] When the end of a duct having an opening is fitted inside another duct, as in Feature A5, there is a concern that the strength of the end having the opening is low and it may bend inward, which could reduce the airtightness between the duct and the other duct, but by increasing the strength by providing a protrusion as described above, such a problem can be prevented. In other words, by applying a protrusion to a duct having the configuration of Feature A5, the effect of providing the protrusion can be further enjoyed.

[0060] [Feature A6] 6. The duct according to claim 1, wherein the cross section of the protrusion is arc-shaped.

[0061] The cross section of the protrusion may be angular or arc-shaped as in feature A6. In addition, if it is arc-shaped, the thickness of the protrusion is stable, and the rigidity of the protrusion is maintained.

[0062] [Feature A7] For vehicle air conditioning, a pair of branched portions in which the end portion is branched into two; a mounting portion provided between the pair of branch portions for fixing the duct; 7. The duct according to claim 1, wherein each of the branched portions is provided with the protrusion.

[0063] As in Feature A7, a duct for vehicle air conditioning having a pair of branch portions may be provided with a protrusion. In this case, by providing a protrusion on each of the pair of branch portions, the end of each branch duct can be strengthened.

[0064] [Feature A8] A manufacturing method in which a duct is manufactured by cutting off a bag portion at an end from a duct intermediate product molded by blow molding, a protruding portion that extends along a cutting portion for cutting off the bag portion and protrudes inward is molded in an opposing portion of the duct intermediate product that is spaced apart from and opposed to an imaginary dividing plane connecting a pair of parting lines.

[0065] As in feature A8, by providing a protrusion extending along the cutting portion, the strength in the vicinity of the cutting portion is increased, deformation of the duct intermediate product when cutting the bag portion is suppressed, and bending of the end of the duct is prevented.

[0066] [Feature A9] 9. The method for manufacturing a duct according to claim 8, wherein the protrusions are formed on both sides of the cut portion.

[0067] As in feature A9, by providing protrusions on both the duct and the bag portion, the strength of the area near the cutting portion sandwiched between the protrusions is improved, and deformation of the duct intermediate product when cutting the bag portion is further suppressed.

[0068] [Feature A10] A duct intermediate product is a blow molded product, and the bag portion at the end is cut off to form a duct, A duct intermediate product in which a protrusion extending along a cutting portion for cutting off the bag portion and protruding inward is molded in an opposing portion that faces away from an imaginary dividing plane connecting a pair of parting lines.

[0069] As in feature A10, by providing a protrusion extending along the cutting portion, the strength is increased, deformation of the duct intermediate product when cutting the bag portion is suppressed, and bending of the end of the duct is prevented.

[0070] [Feature A11] 11. The duct intermediate product according to claim 10, wherein the protrusions are formed on both sides of the cut portion.

[0071] As in feature A11, by providing protrusions on both the duct and the bag portion, the strength of the area near the cutting portion sandwiched between the protrusions is improved, and deformation of the duct intermediate product when cutting the bag portion is further suppressed.

[0072] [Feature A12] The end portion of the duct having the opening according to any one of claims 1 to 7 is fitted inside another duct, A duct fitting structure in which an elastic member that closes the gap between the duct and the other duct is fixed to the outer surface of the end of the duct having the opening, closer to the opening than the protrusion.

[0073] When the end of a duct having an opening is fitted inside another duct, there is a concern that if the end having the opening has low strength and bends inward, the sealing between the duct and the other duct will be reduced. However, by providing a protrusion on the end of the duct having the opening to increase its strength, as in feature A12, such a problem can be prevented. [Explanation of symbols]

[0074] 10 Duct 12 Branch duct (branch section) 13 Mounting part (mounting part) 31A, 31B Upper opposing wall (opposing part and second opposing wall) 32A, 32B Lower opposing wall (opposing part and second opposing wall) 33A, 33B Left side opposing wall (1st opposing wall) 34A, 34B Right facing wall (first facing wall) 47 Parting Line (Parting Line) 50 Disposal bag (bag part) 60,69 Second opening (opening) 70 Linear convex part (protrusion) 71 Linear recess (groove) 80 molds 85 Elastic member (elastic member)

Claims

1. In the duct, a protrusion extending along an edge of the opening and protruding inward at a portion of the end portion having the opening that faces the duct wall, the protrusion not engaging with any other component; the end portion having the opening forms a fitting portion that is fitted into the inside of another duct, A duct in which the outer surface of the end portion having the opening, on the opening side of the protrusion, is a fixing portion to which an elastic member that closes the gap between the other duct is fixed.

2. A duct formed by blow molding, a protrusion extending along an edge of the opening and protruding inward at a portion of the end portion having the opening that faces the duct wall; the end portion having the opening has a rectangular cross section and includes a pair of first opposing walls and a pair of second opposing walls; The pair of first opposing walls each have a parting line, The pair of second opposing walls are formed to have a smaller width than the pair of first opposing walls, The protrusion is disposed on the pair of second opposing walls as the opposing portions.

3. In a duct, a protrusion extending along an edge of the opening and protruding inward at a portion of the end portion having the opening that faces the duct wall; the end portion having the opening forms a fitting portion that is fitted into the inside of another duct, a fixing portion to which an elastic member that closes a gap between the end portion and the other duct is fixed, the fixing portion being a portion of the outer surface of the end portion having the opening closer to the opening than the protruding portion; The cross section of the protrusion is arc-shaped.

4. In a duct, a protrusion extending along an edge of the opening and protruding inward at a portion of the end portion having the opening that faces the duct wall; The end portion having the opening has a rectangular cross section and includes a pair of first opposing walls and a pair of second opposing walls, The pair of first opposing walls each have a parting line, the protruding portion is disposed on the pair of second opposing walls as the opposing portion, The pair of first opposing walls do not include a protrusion extending along an opening edge and protruding inward, The cross section of the protrusion is arc-shaped.

5. A duct described in any one of claims 1 to 4, wherein the outside of the duct corresponding to the protrusion is provided with a groove corresponding to the shape of the protrusion, and both ends of the groove are open in the longitudinal direction.

6. For vehicle air conditioning, a pair of branched portions in which the end portion is branched into two; a mounting portion provided between the pair of branch portions for fixing the duct; 6. The duct according to claim 1, wherein each of the branched portions is provided with a protrusion.

7. An end portion having the opening of the duct according to any one of claims 1 to 6 is fitted inside another duct, A duct fitting structure in which an elastic member that closes the gap between the duct and the other duct is fixed to the outer surface of the end of the duct having the opening, closer to the opening than the protrusion.

8. A duct fitting structure in which an end portion having an opening in a duct is fitted into the inside of another duct, The duct has a protrusion extending along an edge of the opening and protruding inward at a portion of the end portion having the opening that faces the duct wall, The cross section of the protrusion is arc-shaped, A duct fitting structure in which an elastic member that closes the gap between the duct and the other duct is fixed to the outer surface of the end of the duct having the opening, closer to the opening than the protrusion.

Images