Duct connection device

Abstract

To provide a duct connection structure capable of easily connecting an end of a flexible duct with an air conditioning apparatus in an air conditioning facility of a building in a short time.SOLUTION: An outer periphery of a cylindrical connection cylinder body 10 of a duct connection device 5 is covered with a soft heat insulation material 3a of an end 3e of a flexible duct 3. A first lock portion 13 is formed on the connection cylinder body 10, and a first lock receiving portion 44 formed on a connection port member 40 of an air conditioning apparatus 2 and the first lock portion 13 are fitted with each other. A spiral strip 15 is formed on the connection cylinder body 10, and a coil-like core material 3c of the flexible duct 3 and the spiral strip 15 are engaged with each other.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a connection structure in a building air conditioning facility, and more particularly to a duct connection device for connecting the end of a flexible duct to an air conditioning device.

Background Art

[0002] Generally, buildings such as houses, commercial buildings, and factories are provided with air conditioning facilities for ventilation and heating and cooling. For example, ducts forming an air flow path are piped in the ceiling space. The end of the duct is connected to an air conditioning device for ventilation and heating and cooling (see Patent Document 1, etc.). As the duct, a flexible duct having a structure in which a flexible heat insulating material such as glass wool is kept in a cylindrical shape with a coil-shaped core material is known (see Patent Document 2, etc.). A short connection pipe protrudes from the air conditioning device side. The end of the flexible duct is fitted around the outer periphery of the connection pipe, and an adhesive tape or a band is wound around the outer peripheral side of the end of the flexible duct. Further, the flexible duct is prevented from coming off by pins, nails, staples, etc.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional duct connection part, the operations of winding an adhesive tape or a band, and further driving pins or the like are complicated, time-consuming, and require a certain degree of skill. In view of such circumstances, an object of the present invention is to provide a duct connection structure that can easily connect the end of a flexible duct to an air conditioning device in a building air conditioning facility in a short time.

Means for Solving the Problem

[0005] In order to solve the above problems, the present invention provides a duct connection device for connecting a flexible duct and air conditioning equipment, which includes a cylindrical connection cylinder body covering the soft heat insulating material at the end of the flexible duct on the outer periphery, wherein the connection cylinder body includes a first locking portion fitted with a first locking receiving portion formed on the connection port member of the air conditioning equipment, and a spiral strip formed on the connection cylinder body and engaged with the coiled core material of the flexible duct. At the construction site, the flexible duct and the air conditioning equipment can be connected with one touch only by fitting the first locking portion of the connection cylinder body with the first locking receiving portion of the connection port member. Since the heat insulating material of the flexible duct covers the connection cylinder body, the heat insulation property at the duct connection portion is ensured. By engaging the core material with the spiral strip, the flexible duct and the connection cylinder body can be firmly connected, and it can be surely prevented that the connection cylinder body falls off from the flexible duct. The spiral strip may include a spiral groove formed on the inner peripheral surface of the connection cylinder body, or may be a spiral rib protruding from the outer peripheral surface of the connection cylinder body.

[0006] A second locking receiving portion is formed on the connection cylinder body, and it is preferable that an annular band is fitted on the outer periphery of the end of the flexible duct, and a second locking portion locked with the second locking receiving portion is formed on the annular band. By sandwiching the flexible duct between the annular band material and the connection cylinder body, the flexible duct and the connection cylinder body can be joined more surely.

[0007] The duct connection device may further include an annular locking receiving member having the first locking receiving portion and fitted on the outer periphery of the connection port member. As a result, the connection cylinder body is connected to the connection port member via the locking receiving member. Even if the connection port member itself has no first locking receiving portion, the flexible duct can be connected to the air conditioning equipment.

[0008] It is preferable that a notch portion is formed in a part of the circumferential direction of the first locking receiving portion or the first locking portion. When separating the air conditioning equipment and the flexible duct, insert a tool into the notch portion to release the engagement between the first locking portion and the first locking receiving portion. As a result, the duct connection device can be separated from the connection port member.

[0009] It is preferable that a strip piece (knob piece) extending outward from between the first locking receiving portion and the first locking portion is provided on the connection port member or the connection cylinder body. When separating the air conditioning equipment and the flexible duct, deform the first locking portion or the first locking receiving portion by pinching and pulling the strip piece. As a result, the engagement between the first locking portion and the first locking receiving portion can be released and it can be easily separated.

Advantages of the Invention

[0010] According to the present invention, the end of the flexible duct and the air conditioning equipment can be easily connected in a short time.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. <First Embodiment (FIGS. 1 to 5)> FIG. 1 shows the air conditioning facility 1 of a building. The air conditioning facility 1 includes an air conditioning device 2 and a flexible duct 3. The air conditioning device 2 is, for example, a ventilation chamber installed in the ceiling space of the building, but is not limited thereto, and may be an air conditioning module, a heating and cooling module, or a blowout unit. The installation location of the air conditioning device 2 is not limited to the ceiling space, and may be below the ceiling, indoors, or in the wall space. A cylindrical connection port member 40 constituting a connection port 4 is provided on the housing 2a of the air conditioning device 2. The connection port member 40 includes a mouth cylinder portion 41, a tapered flange 42, and a fixed cylinder portion 43. The mouth cylinder portion 41 protrudes outward from the housing 2a of the air conditioning device 2. The flange 42 is applied to the outer surface of the housing 2a. A male screw 43a on the outer periphery of the fixed cylinder portion 43 is screwed with a female screw on the inner periphery of the opening of the housing 2a.

[0013] As shown in Fig. 2, on the side of the outer end portion 42c of the flange 42 facing the housing 2a, a first locking receiving portion 44 that is annular and recessed in a stepped shape is formed. As shown in Fig. 1, at one or a plurality of circumferential positions of the outer end portion 42c of the flange including the first locking receiving portion 44, concave notch portions 45 are formed. The bottom surface of the notch portion 45 is flush with the bottom surface of the first locking receiving portion 44 or is recessed radially inward of the bottom surface of the first locking receiving portion 44. Preferably, a plurality of notch portions 45 are provided at intervals in the circumferential direction of the outer end portion 42c of the flange. Preferably, markings (not shown) are provided at the arrangement positions of the notch portions 45 in the circumferential direction of the connection port member 40.

[0014] As shown in Fig. 1, the flexible duct 3 includes a soft cylindrical heat insulating material 3a made of glass wool or the like, an inner layer 3b and a coiled core material 3c along the inner circumference of the heat insulating material 3a, and an outer layer 3d covering the outer peripheral surface of the heat insulating material 3a. An end portion 3e of the flexible duct 3 is connected to the connection port 4 of the air conditioner 2 via a duct connection device 5.

[0015] As shown in Fig. 3, the duct connection device 5 includes a connection cylinder body 10 (socket) and an annular belt material 20 (ring). The connection cylinder body 10 includes a cylinder main body portion 11, a flange portion 12, a first locking portion 13, and a second locking receiving portion 14. A spiral strip 15 is formed on the cylinder main body portion 11. The spiral strip 15 extends spirally along the circumferential surface of the cylinder main body portion 11 and bulges from the cylinder main body portion 11 toward the outer peripheral side so that the cross section is substantially U-shaped, whereby a spiral groove 15a is formed inside the spiral strip 15. The spiral groove 15a is opened to the inner peripheral surface of the cylinder main body portion 11. The spiral diameter of the spiral strip 15 is substantially equal to the spiral diameter of the core material 3c. The spiral pitch of the spiral strip 15 and thus the spiral groove 15a is substantially equal to the designed spiral pitch (the spiral pitch at neutral without stretching or shrinking) of the core material 3c.

[0016] At the end of the cylinder main body 11 on the duct side (the left side in FIG. 3), the diameter is expanded over the entire circumference to form an annular large-diameter portion 16. The large-diameter portion 16 has substantially the same diameter as the outer peripheral portion of the spiral strip 15. The end of the spiral strip 15 on the duct side (the left side in FIG. 3) is continuously connected to the large-diameter portion 16. A spiral groove 16a communicates with the internal space of the large-diameter portion 16.

[0017] As shown in FIGS. 1 and 3, a flange portion 12 is continuously connected to the end of the cylinder main body 11 on the air-conditioning equipment side (the right end in FIG. 1). The flange portion 12 is tapered and expanded as it moves away from the cylinder main body 11. The taper angle of the flange portion 12 is steeper than the taper angle of the flange 42. The outer end of the flange portion 12 (the end on the large-diameter side) extends annularly toward the air-conditioning equipment side (the right side in FIG. 1), and a first locking portion 13 and a second locking receiving portion 14 are provided on the extended portion.

[0018] The first locking portion 13 has a cylindrical portion 13a and a claw portion 13f, and is formed in an L-shaped cross section. The cylindrical portion 13a has a larger diameter than the outer end portion 42c of the flange 42. A claw portion 13f is provided at the end of the cylindrical portion 13a on the air-conditioning equipment side (the right end in FIG. 2). The claw portion 13f protrudes radially inward from the cylindrical portion 13a and is annular over the entire circumference of the cylindrical portion 13a. The inner diameter of the inner peripheral edge of the claw portion 13f is smaller than the outer diameter of the outer end portion 42c of the flange 42 and larger than the annular bottom surface of the first locking receiving portion 44.

[0019] A second locking receiving portion 14 is provided between the tapered portion 12a of the flange portion 12 and the cylindrical portion 13a of the first locking portion 13. The second locking receiving portion 14 is in the shape of an annular concave groove that opens to the outer peripheral side of the connecting cylinder 10. The outer diameter of the groove wall portion 14a of the second locking receiving portion 14 on the tapered portion 12a side is smaller than the outer diameter of the groove wall portion 14b on the first locking portion 13 side. In short, the outer diameter of the cylindrical portion 13a is larger than the outer diameter of the large-diameter side end of the tapered portion 12a.

[0020] The material of the connecting cylinder 10 is preferably a hard resin, but is not limited thereto and may be a metal.

[0021] As shown in FIGS. 1 and 2, in the connection state of the air-conditioning equipment 2 and the flexible duct 3 by the duct connection device 5, the connection cylinder body 10 covers the outer peripheral side of the connection port member 40. The cylinder main body portion 11 surrounds the mouth cylinder portion 41. The flange portion 12 is overlapped on the outside of the flange 42. The cylindrical portion 13a of the first locking portion 13 surrounds the outer end portion 42c of the flange 42. The claw portion 13f is fitted and locked to the first locking receiving portion 44. Thus, the connection cylinder body 10 is prevented from coming off with respect to the connection port member 40.

[0022] As shown in FIG. 2, in the above connection state, the claw portion 13f abuts or is close to the outer surface of the housing 2a. In a state where the claw portion 13f abuts against the outer surface of the housing 2a, the back corner portion 14c of the second locking receiving portion 14 abuts against the tapered portion near the outer end portion of the flange 42. The rounded corner portion 12c connecting the inner end portion of the flange portion 12 and the cylinder main body portion 11 is close to or abuts against the middle portion of the tapered portion of the flange 42.

[0023] The connection cylinder body 10 in the above connection state is interposed between the heat insulating material 3a and the core material 3c and the inner layer 3b at the end portion 3e of the flexible duct 3. The cylinder main body portion 11 of the connection cylinder body 10 is disposed inside the heat insulating material 3a. In other words, the heat insulating material 3a covers the outer periphery of the cylinder main body portion 11. The end surface of the heat insulating material 3a is applied to the outer surface of the flange portion 12.

[0024] In the above connection state, the core material 3c and the inner layer 3b are inserted between the connection cylinder body 10 and the mouth cylinder portion 41. And the core material 3c is fitted into the spiral groove 15a of the spiral strip 15. The inner layer 3b covers the outer periphery of the mouth cylinder portion 41.

[0025] As shown in Fig. 2, the annular belt member 20 includes a cylindrical portion 21, a second locking portion 22, and a duct pressing portion 23. The cylindrical portion 21 has substantially the same diameter as the cylindrical portion 13a of the first locking portion 13 and is longer in the axial direction than the cylindrical portion 13a. A second locking portion 22 is provided at the end portion on the air-conditioning equipment side (the right end portion in Fig. 2) of the cylindrical portion 21. The second locking portion 22 protrudes radially inward (downward in Fig. 2) from the cylindrical portion 21 and is formed in an annular claw shape that extends over the entire circumference of the cylindrical portion 13a. The inner diameter of the inner peripheral edge of the second locking portion 22 is smaller than the outer diameter of the outer peripheral portion of the annular groove wall portion 14a of the second locking receiving portion 14 and larger than the diameter of the annular groove bottom 14d.

[0026] A duct pressing portion 23 is provided on the side of the annular belt member 20 opposite to the second locking portion 22 (the left side in Fig. 2) with the cylindrical portion 21 interposed therebetween. The duct pressing portion 23 is formed in a cylindrical shape with a smaller diameter than the cylindrical portion 21. A stepped portion 24 is formed between the duct pressing portion 23 and the cylindrical portion 21. The inner diameter of the duct pressing portion 23 is smaller than the outer diameter of the heat insulating material 3a of the flexible duct 3 in the non-compressed state. The annular belt member 20 is preferably made of a resin that is softer than the connecting cylindrical body 10 and is elastically deformable, but is not limited thereto, and may be made of a thin plate-like metal as long as it is preferably soft.

[0027] As shown in Figs. 1 and 2, in the connection state of the air-conditioning equipment 2 and the flexible duct 3 by the duct connection device 5, the annular belt member 20 is fitted on the outer periphery of the end portion 3e of the flexible duct 3. The heat insulating material 3a and the outer layer 3d of the end portion 3e of the flexible duct 3 are sandwiched between the annular belt member 20 and the connecting cylindrical body 10. The duct pressing portion 23 compresses the heat insulating material 3a by pressing the end portion 3e of the flexible duct 3 from the outer peripheral side.

[0028] In the connection state, the second locking portion 22 is fitted and locked to the second locking receiving portion 14 from the outer peripheral side. An outer layer 3d is sandwiched between the second locking portion 22 and the second locking receiving portion 14. The end portion of the outer layer 3d extends outward from between the second locking portion 22 and the second locking receiving portion 14 and is folded back onto the outer peripheral surface of the annular strip 20.

[0029] The flexible duct 3 and the air conditioning equipment 2 are connected by the duct connection device 5 as follows. The duct connection device 5 is previously attached to the end portion 3e of the flexible duct 3. First, as shown by the white arrow in FIG. 3, the annular strip 20 is fitted onto the outer periphery of the end portion 3e of the flexible duct 3. When fitting, if necessary, the soft annular strip 20 is elastically deformed and the soft heat insulating material 3a of the flexible duct 3 is compressed and deformed. As a result, as shown in FIG. 4, the annular strip 20 is disposed slightly deeper inside the end portion 3e of the flexible duct 3. Preferably, the distance from the end face of the heat insulating material 3a to the annular strip 20 on the flexible duct 3 is made larger than the axial length of the cylindrical main body portion 11.

[0030] Subsequently, as shown in FIG. 4, the connection cylindrical body 10 is fitted onto the outer periphery of the end portion 3e of the flexible duct 3. That is, the cylindrical main body portion 11 is inserted between the heat insulating material 3a and the core material 3c and the inner layer 3b. At this time, the end portion of the core material 3c is guided from the inside of the large diameter portion 16 to the end portion of the spiral groove 15a. Further, by inserting the connection cylindrical body 10 while rotating it with respect to the flexible duct 3, the core material 3c is fitted into the spiral groove 15a. As a result, the core material 3c and the spiral strip 15 are engaged. Consequently, the connection cylindrical body 10 can be firmly connected to the end portion 3e of the flexible duct 3, and it is possible to reliably prevent the connection cylindrical body 10 from falling off from the flexible duct 3. At this stage, since the annular strip 20 is retracted deeper inside the end portion 3e of the flexible duct 3, the fitting operation of the connection cylindrical body 10 can be easily performed.

[0031] Next, as shown in FIG. 5, the annular strip 20 is slid toward the end 3e of the flexible duct 3. Then, the second locking portion 22 hits against the tapered surface of the flange portion 12 while being elastically deformed with the outer layer 3d interposed therebetween, gets over the groove wall portion 14a, and fits into and is locked to the second locking receiving portion 14 (FIG. 2). The heat insulating material 3a is sandwiched and compressed between the duct pressing portion 23 and the cylindrical main body portion 11. Thereby, the duct connection device 5 is firmly attached to the end 3e of the flexible duct 3. The end of the outer layer 3d is folded back onto the outer peripheral surface of the annular strip 20.

[0032] As shown in FIG. 1, when connecting the air conditioning equipment 2 and the flexible duct 3 at the construction site of the building air conditioning equipment 1, the duct connection device 5 at the end 3e of the flexible duct 3 is axially aligned with the connection port member 40 and then pushed straight toward the air conditioning equipment 2. Thereby, as shown in FIG. 2, the connection cylindrical body 10 is fitted onto the outer periphery of the mouth cylindrical portion 41, and the first locking portion 13 hits against the tapered surface of the flange 42 and is elastically deformed, gets over the outer end portion 42c, and fits into and is locked to the first locking receiving portion 44. In this way, the air conditioning equipment 2 and the flexible duct 3 can be easily connected via the duct connection device 5 in an extremely short time with almost no requirement for work proficiency. According to the duct connection structure by the duct connection device 5, the heat insulating material 3a of the flexible duct 3 covers the outer periphery of the connection cylindrical body 10, so that the heat insulation property at the connection portion can be ensured.

[0033] When separating the air conditioning equipment 2 and the flexible duct 3, a tool is inserted into the notch portion 45 to elastically deform the first locking portion 13 and release the engagement between the first locking portion 13 and the first locking receiving portion 44. Thereby, the connection cylindrical body 10 is separated from the connection port 4. Consequently, the flexible duct 3 can be separated from the air conditioning equipment 2.

[0034] Next, another embodiment of the present invention will be described. Regarding the configurations overlapping with those in the above-described embodiments in the following embodiments, the same reference numerals are given in the drawings and the description thereof is omitted. <Second Embodiment (Figs. 6 to 7)> As shown in Fig. 6, in the second embodiment of the present invention, the first locking receiving portion 44 (see Fig. 1) is not provided on the connecting port member 40B constituting the connecting port 4 of the air conditioner 2.

[0035] As shown in Figs. 6 and 7, the duct connection device 5B according to the second embodiment includes, in addition to the connection cylinder 10 and the annular belt material 20, a locking receiving member 30 separate from the connecting port member 40B. The locking receiving member 30 is formed in an annular shape with an outer peripheral surface 31 that expands in diameter in a tapered shape toward the air conditioner side. A first locking receiving portion 33 formed of a stepped annular recess is formed on the outer peripheral portion of the expanded diameter side end surface 32 of the locking receiving member 30.

[0036] As shown in Fig. 7, in the duct connection structure of the second embodiment, the cylindrical mouth cylinder portion 41 of the connecting port member 40B is inserted into the central hole 34 of the locking receiving member 30, whereby the locking receiving member 30 is fitted on the outer periphery of the connecting port member 40. The expanded diameter side end surface 32 of the locking receiving member 30 abuts against the flat flange 46 of the connecting port member 40B. The flange portion 12 of the connection cylinder 10 covers the outside of the locking receiving member 30. The first locking portion 13 is locked to the first locking receiving portion 33. Thereby, the connection cylinder 10 is connected to the connecting port member 40B via the locking receiving member 30. Therefore, even if the first locking receiving portion is not provided on the connecting port member 40B itself, the flexible duct 3 can be connected to the connecting port 4 of the air conditioner 2.

[0037] <Third Embodiment (Figs. 8 to 10)> As shown in Fig. 9(a), in the duct connection device 5C of the third embodiment of the present invention, a spiral rib 17 is formed on the outer peripheral surface of the cylindrical main body portion 11 of the connection cylinder 10. As shown in Fig. 9(b), a spiral groove 17b is formed in a portion of the inner peripheral surface of the cylindrical main body portion 11 corresponding to the spiral rib 17. However, the spiral groove 17b may be eliminated, and the entire inner peripheral surface of the cylindrical main body portion 11 may be formed into a smooth cylindrical surface without irregularities. A large-diameter portion 16 (see Fig. 1) is not formed at the duct-side end portion (the left end portion in Fig. 9(a)) of the connection cylinder 10, and the entire cylindrical main body portion 11 is in a straight cylindrical shape.

[0038] As shown in Fig. 8, the inner layer 3b at the end portion 3e of the flexible duct 3 covers the outer peripheral surface of the cylindrical main body portion 11. Further, the core material 3c is wound around the outer peripheral surface of the cylindrical main body portion 11 and engaged with the spiral rib 17. Preferably, the core material 3c is hooked from the air conditioner 2 side (the right side in Fig. 8) with respect to the spiral rib 17. Note that the core material 3c may partially ride on the spiral rib 17 and intersect the spiral rib 17.

[0039] The heat insulating material 3a directly covers the outer periphery of the inner layer 3b and the core material 3c at the end portion 3e of the flexible duct 3. Therefore, the entire end portion 3e of the flexible duct 3 is disposed on the outer peripheral side of the cylindrical main body portion 11. The inner peripheral surface of the cylindrical main body portion 11 directly faces the air passage of the air conditioning equipment 1. According to the third embodiment, when the connection cylinder 10 is incorporated into the end portion 3e of the flexible duct 3, it is possible to prevent the heat insulating material 3a at the end portion 3e from being turned up. Further, it is possible to avoid the end portion of the inner layer 3b hanging down into the air passage of the air conditioning equipment 1 and vibrating due to the air flow. Therefore, the end portion treatment of the inner layer 3b for preventing the vibration is unnecessary.

[0040] As shown in Fig. 10, a strip 50 (grip strip) is provided on the outer surface of the flange 42 of the connection port member 40. The strip 50 is constituted by, for example, a resin tape having a constant width. The fixing end portion 51 of the strip 50 is attached via an adhesive (not shown). The intermediate portion 52 of the strip 50 is sandwiched between the first locking receiving portion 44 and the first locking portion 13 and is bent. The working end portion 53 of the strip 50 extends outward from between the first locking receiving portion 44 and the first locking portion 13.

[0041] When separating the flexible duct 3 from the air conditioning equipment 2, by grasping and pulling the working end portion 53 of the strip 50, the first locking portion 13 is deformed to release the engagement between the first locking portion 13 and the first locking receiving portion 44. Thereby, the connection cylinder portion 10 can be easily separated from the connection port 4. Therefore, there is no need to provide the notch portion 45 (see Fig. 1) in the connection port member 40.

[0042] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit thereof. For example, the annular band 20 may be omitted. Instead of the annular band 20, an adhesive tape, a clamping band, or the like may be wound around the outer periphery of the end portion 3e of the flexible duct 3 to fix the connection cylinder body 10 and the flexible duct 3. In this case, the second locking receiving portion 14 of the connection cylinder body 10 is unnecessary. Instead of providing the notch portion 45 in the connection port member 40 for inserting a separation tool when separating the flexible duct 3 and the air conditioning equipment 2, a notch portion for inserting the separation tool may be provided in a part of the circumferential direction of the first locking portion 13. In the first and second embodiments (Figs. 1 to 7), a separation strip 50 may also be provided. The strip 50 may be attached to the connection cylinder body 10. In the third embodiment (Figs. 8 to 10), similar to the second embodiment, a locking receiving member 30 separate from the connection port member 40 of the air conditioning equipment 2 may be provided, and instead of the strip 59, a notch portion 45 similar to that of the first embodiment may be provided. A packing may be provided on the connecting cylinder 10 to ensure airtightness.

Industrial Applicability

[0043] The present invention is applicable to air conditioning equipment for buildings such as single-family houses, apartment houses, commercial buildings, factories, and other buildings.

Explanation of Signs

[0044] 2 Air conditioner 3 Flexible duct 3a Heat insulating material 3b Inner layer 3c Core material 3d Outer layer 3e End part 4 Connection port 40 Connection port member 41 Mouth cylinder part 42 Flange 44 First locking receiving part 45 Notch part 5 Duct connection device 10 Connecting cylinder 13 First locking part 14 Second locking receiving part 15 Spiral strip 15a Spiral groove 20 Annular strip 22 Second locking part 23 Duct pressing part 40B Connection port member 30 Locking receiving member 33 First locking receiving part 5B Duct connection device 17 Spiral rib (spiral strip) 17b Spiral groove 50 Strip piece

Claims

1. A duct connection device for connecting a flexible duct and an air conditioning device, comprising: a cylindrical connection cylinder body in which a soft heat insulating material at an end of the flexible duct covers an outer periphery; the connection cylinder body includes a first locking portion that is fitted with a first locking receiving portion formed in a connection port member of the air conditioning device, and a spiral strip formed in the connection cylinder body and engaged with a coiled core material of the flexible duct; a second locking receiving portion is formed in the connection cylinder body; a duct connection device, characterized in that an annular band is fitted on an outer periphery of an end of the flexible duct, and a second locking portion that is locked with the second locking receiving portion is formed in the annular band.

2. The duct connection device according to claim 1, further comprising an annular locking receiving member that has the first locking receiving portion and is fitted on an outer periphery of the connection port member.

3. The duct connection device according to claim 1 or 2, characterized in that a notch portion is formed in a part of a circumferential direction of the first locking receiving portion or the first locking portion.

4. The duct connection device according to any one of claims 1 to 3, characterized in that a strip piece extending outward from between the first locking receiving portion and the first locking portion is provided in the connection port member or the connection cylinder body.

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