Duct joint

Abstract

To provide a duct joint capable of more efficiently performing connected work for ducts compared to a case of using a flange joint.SOLUTION: A duct joint according to one aspect of the present disclosure comprises a concave-side joint including a frame-shaped receiving frame on an outer peripheral portion, and a convex-side joint including a frame-shaped insertion frame on the outer peripheral portion that is inserted into the receiving frame and that is combined with the concave-side joint. The inner peripheral surface of the receiving frame is parallel to an axial core of the receiving frame or is inclined away from the axial core of the receiving frame toward a tip. The outer peripheral surface of the insertion frame is inclined toward the axial core of the insertion frame toward the tip.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to duct fittings. [Background technology]

[0002] A duct joint is a joint that connects ducts. A flange joint such as that described in Patent Document 1 can be used as a duct joint. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2023-541686 Summary of the Invention [Problem to be solved by the invention]

[0004] When connecting ducts, the two ducts to be connected must be aligned so that their axes coincide. When using flange joints as duct joints, this alignment is time-consuming, making it difficult to efficiently connect the ducts.

[0005] Therefore, an object of the present disclosure is to provide a duct joint that allows duct connection work to be performed more efficiently than with a flange joint. [Means for solving the problem]

[0006] A duct fitting according to one aspect of the present disclosure comprises a concave side fitting including a frame-shaped receiving frame on its outer periphery, and a convex side fitting including a frame-shaped insertion frame on its outer periphery that is inserted into the receiving frame and that is combined with the concave side fitting, wherein the inner peripheral surface of the receiving frame is parallel to the axis of the receiving frame or is inclined so as to move away from the axis of the receiving frame as it approaches the tip, and the outer peripheral surface of the insertion frame is inclined so as to move closer to the axis of the insertion frame as it approaches the tip.

[0007] Furthermore, a duct fitting according to another aspect of the present disclosure comprises a concave side fitting including a frame-shaped receiving frame on its outer periphery, and a convex side fitting including a frame-shaped insertion frame on its outer periphery that is inserted into the receiving frame and that is combined with the concave side fitting, wherein the inner peripheral surface of the receiving frame is inclined so as to move away from the axis of the receiving frame as it approaches the tip, and the outer peripheral surface of the insertion frame is either parallel to the axis of the insertion frame or is inclined so as to move closer to the axis of the insertion frame as it approaches the tip. [Effects of the Invention]

[0008] According to the above duct joint, the duct connection work can be carried out more efficiently than with a flange joint. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a duct joint according to a first embodiment before assembly. [Figure 2] FIG. 2 is a cross-sectional view of the duct joint according to the first embodiment when assembled. [Figure 3] FIG. 3 is an enlarged view of the area in FIG. 1 including the receiving frame and the insert frame. [Figure 4] FIG. 4 is a cross-sectional view of a duct joint according to the second embodiment before assembly. [Figure 5] FIG. 5 is a cross-sectional view of the duct joint according to the second embodiment when assembled. [Figure 6] FIG. 6 is an enlarged view of the area including the receiving frame and the insert frame in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) Hereinafter, embodiments will be described. First, a duct fitting 100 according to a first embodiment will be described. Fig. 1 is a cross-sectional view of the duct fitting 100 according to the first embodiment before assembly. Fig. 2 is a cross-sectional view of the duct fitting 100 according to the first embodiment after assembly.

[0011] The duct joint 100 is a joint that connects the ducts 101 and 102. In this embodiment, the ducts 101 and 102 are cylindrical. However, the shape and size of the ducts 101 and 102 are not limited, and the ducts 101 and 102 may be rectangular tubular, for example. Furthermore, the duct joint 100 may be a part of the ducts 101 and 102, or may be a separate member from the ducts 101 and 102.

[0012] As shown in Figure 1, the duct joint 100 comprises a concave side joint 10, a convex side joint 20, and a fastener 30. These components will be described below in order.

[0013] <Concave side joint> The concave side joint 10 is a part located in one of the ducts 101, 102 to be connected. The concave side joint 10 is combined with the convex side joint 20 to connect the connecting ducts 101, 102. The concave side joint 10 has a frame-like shape. The concave side joint 10 of this embodiment is a circular frame-like shape. However, the concave side joint 10 may have a shape other than a circular frame-like shape, such as a rectangular frame-like shape. Furthermore, the concave side joint 10 of this embodiment is mainly made of metal. However, the material from which the concave side joint 10 is formed is not limited, and for example, the concave side joint 10 may be mainly made of resin.

[0014] As shown in FIG. 1, the concave side joint 10 of this embodiment includes a receiving frame 11 and an inner stepped portion 12.

[0015] The receiving frame 11 is a portion that receives an insertion frame 21 of the convex joint 20, which will be described later. The receiving frame 11 has a frame-like shape, similar to the concave joint 10. FIG. 3 is an enlarged view of the range in FIG. 1 that includes the receiving frame 11 and the insertion frame 21, which will be described later. In FIGS. 1 to 3, the dashed dotted line labeled 13 indicates the axis of the receiving frame 11.

[0016] 3, in this embodiment, the inner peripheral surface 14 of the receiving frame 11 is inclined so as to move away from the axis 13 of the receiving frame 11 toward the tip, i.e., toward the outer end in the axial direction of the receiving frame 11. In other words, the area of ​​the region surrounded by the inner peripheral surface 14 of the receiving frame 11 increases toward the tip. In other words, the inner peripheral surface 14 of the receiving frame 11 widens toward the tip.

[0017] In this embodiment, the inner peripheral surface 14 of the receiving frame 11 is linear in a cross section including the axis 13 of the receiving frame 11. In other words, when a cross section of the receiving frame 11 cut to include the axis 13 of the receiving frame 11 is viewed from a direction perpendicular to the cross section, the inner peripheral surface 14 of the receiving frame 11 is linear. However, the inner peripheral surface 14 of the receiving frame 11 is not limited to this shape, and may be, for example, arc-shaped in a cross section including the axis 13 of the receiving frame 11.

[0018] As described above, the inner peripheral surface 14 of the receiving frame 11 is inclined so as to move away from the axis 13 of the receiving frame 11 toward the tip. Therefore, as shown in FIG. 3, in a cross-sectional view including the axis 13 of the receiving frame 11, the angle α formed between the inner peripheral surface 14 of the receiving frame 11 and the axis 13 of the receiving frame 11 (hereinafter referred to as the "receiving frame inclination angle") is greater than 0 degrees. Note that in FIG. 3, the dashed line labeled 15 is a line parallel to the axis 13 of the receiving frame 11. Furthermore, in this embodiment, the inner peripheral surface 14 of the receiving frame 11 may be parallel to the axis 13 of the receiving frame 11. In this case, the receiving frame inclination angle α is 0 degrees.

[0019] The inner step portion 12 is a portion located on the inner peripheral side of the receiving frame 11. The inner step portion 12 in this embodiment is located near the base end of the receiving frame 11, that is, near the inner end of the receiving frame 11 in the axial direction. The inner step portion 12 in this embodiment has a frame-like shape and is formed continuously along the receiving frame 11. However, the inner step portion 12 may be formed intermittently along the receiving frame 11 rather than continuously.

[0020] The inner step portion 12 has an inner facing surface 16 that faces the convex joint 20. In this embodiment, the inner facing surface 16 is perpendicular to the axis 13 of the receiving frame 11. In this embodiment, the inner facing surface 16 is formed of an elastic material such as rubber. However, the inner facing surface 16 may be formed of the same material as the rest of the inner facing surface 16 of the concave joint 10.

[0021] <Convex side joint> As shown in FIG. 1 , the convex joint 20 is a part located in the other duct 102 of the ducts 101 and 102 to be connected. The convex joint 20 is combined with the concave joint 10 to connect the connecting ducts 101 and 102. The convex joint 20 has a frame-like shape. In this embodiment, the convex joint 20 is a circular frame-like shape. However, the convex joint 20 may have a shape other than a circular frame-like shape, such as a rectangular frame-like shape. Furthermore, the convex joint 20 in this embodiment is made of metal. However, the material from which the convex joint 20 is made is not limited, and for example, the convex joint 20 may be made of resin.

[0022] As shown in FIG. 1, the convex joint 20 of this embodiment includes an insertion frame 21 and an outer stepped portion 22.

[0023] The insertion frame 21 is a part that is inserted into the receiving frame 11 of the concave joint 10. The insertion frame 21 has a frame-like shape, similar to the convex joint 20. In Figures 1 to 3, the dashed line labeled 23 indicates the axis of the insertion frame 21. As shown in Figure 2, when the concave joint 10 and the convex joint 20 are combined, the inner peripheral surface 14 of the receiving frame 11 and the outer peripheral surface 24 of the insertion frame 21 are in contact. At this time, a portion of the inner peripheral surface 14 of the receiving frame 11 may be in contact with the outer peripheral surface 24 of the insertion frame 21, or the entire inner peripheral surface 14 of the receiving frame 11 may be in contact with the outer peripheral surface 24 of the insertion frame 21. In other words, at least a portion of the inner peripheral surface 14 of the receiving frame 11 is in contact with the outer peripheral surface 24 of the insertion frame 21. However, when the concave side joint 10 and the convex side joint 20 are combined, the inner peripheral surface 14 of the receiving frame 11 does not have to be in contact with the outer peripheral surface 24 of the insertion frame 21 .

[0024] 3, in this embodiment, the outer peripheral surface 24 of the insertion frame 21 is inclined so as to approach the axis 23 of the insertion frame 21 toward the tip, that is, toward the outer end in the axial direction of the insertion frame 21. In other words, the area of ​​the region surrounded by the outer peripheral surface 24 of the insertion frame 21 becomes smaller toward the tip. In other words, the insertion frame 21 becomes thinner toward the tip.

[0025] In this embodiment, the outer peripheral surface 24 of the insertion frame 21 is linear in a cross section including the axis 23 of the insertion frame 21. In other words, when a cross section of the insertion frame 21 cut to include the axis 23 of the insertion frame 21 is viewed from a direction perpendicular to the cross section, the outer peripheral surface 24 of the insertion frame 21 is linear. However, the outer peripheral surface 24 of the insertion frame 21 is not limited to this shape, and may be, for example, arc-shaped in a cross section including the axis 23 of the insertion frame 21.

[0026] As described above, the outer peripheral surface 24 of the insertion frame 21 is inclined so as to approach the axis 23 of the insertion frame 21 as it approaches the tip. Therefore, as shown in Fig. 3, in a cross-sectional view including the axis 23 of the insertion frame 21, the angle β formed between the outer peripheral surface 24 of the insertion frame 21 and the axis 23 of the insertion frame 21 (hereinafter referred to as the "insertion frame inclination angle") is greater than 0 degrees. Note that in Fig. 3, the dashed line designated by reference numeral 25 is a line parallel to the axis 23 of the insertion frame 21.

[0027] In this embodiment, the receiving frame inclination angle α is smaller than the insertion frame inclination angle β. Furthermore, the insertion frame inclination angle β is 1 degree or less. This allows the concave side joint 10 and the convex side joint 20 to be easily assembled and separated. As described above, the receiving frame inclination angle α is 0 degrees or greater. Furthermore, the insertion frame inclination angle β is greater than 0 degrees. In summary, in this embodiment, the receiving frame inclination angle α is greater than 0 degrees and smaller than the insertion frame inclination angle β, and the insertion frame inclination angle β is greater than 0 degrees and 1 degree or less. However, it is more preferable that the insertion frame inclination angle β be 0.8 degrees or less.

[0028] In this embodiment, the shape of the receiving frame 11 and the shape of the insertion frame 21 are the same. However, the tip portion of the inner peripheral surface 14 of the receiving frame 11, i.e., the entrance portion of the receiving frame 11, is wider than the tip portion of the outer peripheral surface 24 of the insertion frame 21. Furthermore, the tip portion of the inner peripheral surface 14 of the receiving frame 11, i.e., the entrance portion of the receiving frame 11, is narrower than the base end portion of the outer peripheral surface of the insertion frame 21. Furthermore, the base end portion of the inner peripheral surface 14 of the receiving frame 11, i.e., the innermost portion of the receiving frame 11, is narrower than the tip portion of the outer peripheral surface of the insertion frame 21.

[0029] The outer step portion 22 is a portion located on the outer peripheral side of the insertion frame 21. In this embodiment, the outer step portion 22 is located near the base end of the insertion frame 21, that is, near the inner end of the insertion frame 21 in the axial direction. In addition, the outer step portion 22 in this embodiment has a frame-like shape and is formed continuously along the receiving frame 11. Furthermore, the outer step portion 22 has an outer facing surface 26 that faces the concave-side joint 10. In addition, the outer facing surface 26 in this embodiment is perpendicular to the axis 23 of the insertion frame 21.

[0030] 2, when the concave side joint 10 and the convex side joint 20 are combined, the tip portion of the insertion frame 21 comes into contact with the inner opposing surface 16 of the inner step portion 12. As a result, when the concave side joint 10 and the convex side joint 20 are combined, the relative positions of the concave side joint 10 and the convex side joint 20 in the axial direction are determined to be constant. The axial direction here is the direction that coincides with the direction in which the axial center 13 of the receiving frame 11 extends and the direction in which the axial center 23 of the insertion frame 21 extends. Furthermore, because the inner opposing surface 16 is formed of an elastic material, the tip portion of the insertion frame 21 and the inner opposing surface 16 of the inner step portion 12 come into close contact with each other, which makes it possible to prevent fluid in the ducts 101, 102 from leaking out from between them.

[0031] On the other hand, as shown in Fig. 3, the axial dimension A from the inner opposing surface 16 of the concave side joint 10 to the tip of the receiving frame 11 is smaller than the axial dimension B from the outer opposing surface 26 of the convex side joint 20 to the tip of the insertion frame 21. Therefore, as shown in Fig. 2, in this embodiment, when the concave side joint 10 and the convex side joint 20 are combined, the tip portion of the receiving frame 11 does not contact the outer opposing surface 26 of the outer step portion 22. However, when the concave side joint 10 and the convex side joint 20 are combined, the tip portion of the receiving frame 11 may contact the outer opposing surface 26 of the outer step portion 22.

[0032] Furthermore, the shape and size of the inner peripheral edge of the concave side joint 10 when viewed from the axial direction of the receiving frame 11 match the shape and size of the inner peripheral edge of the convex side joint 20 when viewed from the axial direction of the insertion frame 21. Therefore, as shown in Figure 2, when the concave side joint 10 and the convex side joint 20 are combined, a step is unlikely to occur at the boundary between the concave side joint 10 and the convex side joint 20, and flow path resistance at the boundary between the concave side joint 10 and the convex side joint 20 can be suppressed.

[0033] <Fastener> The fastener 30 is a device that limits movement of the convex joint 20 relative to the concave joint 10. As shown in FIG.

[0034] The locking member 31 is a member that locks onto the locked member 32. The locking members 31 of this embodiment are located at multiple circumferential positions on the outer periphery of the concave side joint 10, and are attached to the concave side joint 10 via support parts 33. The support parts 33 have support shafts 34 that are perpendicular to the axial direction of the receiving frame 11, and the locking members 31 are rotatably supported on the support shafts 34.

[0035] The locked member 32 is a member to which the locking member 31 is locked. In this embodiment, the locked members 32 are located at multiple circumferential positions on the outer periphery of the convex joint 20 that correspond to the locking members 31. As shown in FIG. 2 , when the concave joint 10 and the convex joint 20 are combined, the locking member 31 is locked to the locked member 32. This allows the fastener 30 to restrict movement of the convex joint 20 in the axial direction relative to the concave joint 10. The axial direction here is the direction that coincides with the direction in which the axis 13 of the receiving frame 11 extends and the direction in which the axis 23 of the insertion frame 21 extends.

[0036] The fastener 30 is not limited to the configuration described above as long as it is configured so that the locking member 31 can be locked to the locked member 32 when the concave joint 10 and the convex joint 20 are combined. In addition, in this embodiment, the locking member 31 is located in the concave joint 10 and the locked member 32 is located in the convex joint 20, but the locking member 31 may be located in the convex joint 20 and the locked member 32 may be located in the concave joint 10. The fastener 30 may also include a locking mechanism that maintains the locking member 31 locked to the locked member 32.

[0037] <Duct connection method> Next, a description will be given of a method for connecting the ducts 101 and 102. In this embodiment, the ducts 101 and 102 are connected by combining the concave side joint 10 and the convex side joint 20 provided on the ducts 101 and 102, respectively.

[0038] To combine the concave side joint 10 and the convex side joint 20, first, the insertion frame 21 of the convex side joint 20 is inserted into the inlet portion of the receiving frame 11 of the concave side joint 10. As described above, the tip portion of the inner circumferential surface 14 of the receiving frame 11, which is the inlet portion of the receiving frame 11, is wider than the tip portion of the outer circumferential surface 24 of the insertion frame 21. Therefore, even if the axis 23 of the insertion frame 21 and the axis 13 of the receiving frame 11 are slightly misaligned, the insertion frame 21 of the convex side joint 20 can be inserted into the receiving frame 11 of the concave side joint 10.

[0039] Next, the insertion frame 21 is pushed into the receiving frame 11 until the tip portion of the insertion frame 21 contacts the inner stepped portion 12 of the concave-side joint 10. As described above, the outer peripheral surface 24 of the insertion frame 21 is inclined, so when the insertion frame 21 is pushed into the receiving frame 11, the outer peripheral surface 24 of the insertion frame 21 and the inner peripheral surface 14 of the receiving frame 11 come into contact. As a result, the axis 23 of the insertion frame 21 and the axis 13 of the receiving frame 11 coincide with each other, and therefore the axes of both ducts 101 and 102 also coincide with each other. Note that after the axes of both ducts 101 and 102 coincide with each other, the outer peripheral surface 24 of the insertion frame 21 and the inner peripheral surface 14 of the receiving frame 11 do not need to come into contact with each other.

[0040] 2, the locking member 31 of the fastener 30 is locked to the locked member 32. This restricts the axial movement of the convex side joint 20 relative to the concave side joint 10, completing the connection of the ducts 101 and 102.

[0041] As described above, according to this embodiment, the ducts 101 and 102 are aligned by pushing the insertion frame 21 into the receiving frame 11. Therefore, the alignment of the ducts 101 and 102 can be substantially omitted, and the work of connecting the ducts 101 and 102 can be carried out efficiently. Furthermore, in the work of removing the ducts 101 and 102, the insertion frame 21 is supported by the receiving frame 11 until it is completely removed from the receiving frame 11. Therefore, the work of removing the ducts 101 and 102 can also be carried out efficiently.

[0042] (Second embodiment) Next, a duct joint 200 according to a second embodiment will be described. Fig. 4 is a cross-sectional view of the duct joint 200 according to the second embodiment before assembly. Fig. 5 is a cross-sectional view of the duct joint 200 according to the second embodiment after assembly. Fig. 6 is an enlarged view of the range including the receiving frame 11 and the insertion frame 21 in Fig. 4.

[0043] The duct fitting 200 of the second embodiment differs from the duct fitting 100 of the first embodiment mainly in the relationship between the receiving frame inclination angle α and the insertion frame inclination angle β, and the relationship between the axial dimensions of the receiving frame 11 and the insertion frame 21.

[0044] Below, the duct fitting 200 according to the second embodiment will be described, focusing on the configuration that differs from the duct fitting 100 according to the first embodiment, and the configuration that is common to or corresponds to the duct fitting 100 according to the first embodiment will be given the same reference symbols and will not be described again.

[0045] As shown in Fig. 4, the duct joint 200 according to this embodiment, like the duct joint 100 according to the first embodiment, is provided with a concave side joint 10 including a receiving frame 11 and a convex side joint 20 including an insertion frame 21. In this embodiment, the inner peripheral surface 14 of the receiving frame 11 is inclined so as to move away from the axis 13 of the receiving frame 11 toward the tip, and the outer peripheral surface 24 of the insertion frame 21 is either parallel to the axis 23 of the insertion frame 21 or is inclined so as to move closer to the axis 23 of the insertion frame 21 toward the tip. In other words, in this embodiment, it is also permissible for the outer peripheral surface 24 of the insertion frame 21 to be parallel to the axis 23 of the insertion frame 21.

[0046] As shown in FIG. 6, in this embodiment, the frame inclination angle α is greater than the insertion frame inclination angle β. However, the frame inclination angle α is 1 degree or less. Therefore, in this embodiment, the frame inclination angle α is greater than 0 degrees and less than 1 degree, and the insertion frame inclination angle β is greater than 0 degrees and less than the frame inclination angle α. However, it is more preferable that the frame inclination angle α is 0.8 degrees or less. Meanwhile, as shown in FIG. 5, in this embodiment, when the concave joint 10 and the convex joint 20 are combined, at least a portion of the inner peripheral surface 14 of the frame 11 and the outer peripheral surface 24 of the insertion frame 21 come into contact. However, when the concave joint 10 and the convex joint 20 are combined, the inner peripheral surface 14 of the frame 11 and the outer peripheral surface 24 of the insertion frame 21 do not necessarily have to come into contact.

[0047] 6, the axial dimension A from the inner opposing surface 16 of the concave joint 10 to the tip of the receiving frame 11 is larger than the axial dimension B from the outer opposing surface 26 of the convex joint 20 to the tip of the insertion frame 21. Therefore, as shown in FIG. 5, in this embodiment, when the concave joint 10 and the convex joint 20 are combined, the tip portion of the insertion frame 21 does not contact the inner opposing surface 16 of the inner stepped portion 12, and the tip portion of the receiving frame 11 contacts the outer opposing surface 26 of the outer stepped portion 22. In this embodiment, the outer opposing surface 26 is made of an elastic material.

[0048] The above is a description of the duct joint 200 according to the second embodiment. The duct joint 200 according to the second embodiment is configured as described above, but for the same reasons as the duct joint 100 according to the first embodiment, the work of connecting and disconnecting the ducts 101, 102 can be carried out efficiently.

[0049] (summary) The first item disclosed in this specification is a duct fitting comprising: a concave-side fitting including a frame-shaped receiving frame on its outer periphery; and a convex-side fitting including a frame-shaped insertion frame on its outer periphery that is inserted into the receiving frame and that is combined with the concave-side fitting, wherein the inner periphery of the receiving frame is parallel to the axis of the receiving frame or is inclined so as to move away from the axis of the receiving frame toward the tip, and the outer periphery of the insertion frame is inclined so as to move closer to the axis of the insertion frame toward the tip.

[0050] According to this configuration, it is possible to substantially omit the need to align the ducts, and the duct connection work can be carried out efficiently.

[0051] The second item disclosed in this specification is a duct fitting comprising: a concave-side fitting including a frame-shaped receiving frame on its outer periphery; and a convex-side fitting including a frame-shaped insertion frame on its outer periphery that is inserted into the receiving frame and that is combined with the concave-side fitting, wherein the inner circumferential surface of the receiving frame is inclined so as to move away from the axis of the receiving frame as it approaches the tip, and the outer circumferential surface of the insertion frame is either parallel to the axis of the insertion frame or is inclined so as to move closer to the axis of the insertion frame as it approaches the tip.

[0052] Even with this configuration, it is possible to substantially omit the need to align the ducts, and the duct connection work can be carried out efficiently.

[0053] A third item disclosed in this specification is a duct fitting according to the first or second item, wherein the concave side fitting includes an inner step portion located more inward than the receiving frame, and when the concave side fitting and the convex side fitting are combined, the tip of the insertion frame contacts the inner step portion.

[0054] According to this configuration, when the concave side joint and the convex side joint are combined, the relative positions of the concave side joint and the convex side joint in the axial direction can be kept constant.

[0055] A fourth item disclosed in this specification is the duct joint according to the third item, wherein the inner stepped portion has an inner facing surface formed of an elastic material.

[0056] According to this configuration, the tip portion of the insertion frame and the inner opposing surface of the inner step portion are in close contact with each other, making it possible to prevent the fluid in the duct from leaking out from between them.

[0057] A fifth item disclosed in this specification is a duct fitting according to the first or second item, wherein the convex side fitting includes an outer step portion located on the outer peripheral side of the insertion frame, and when the concave side fitting and the convex side fitting are combined, a tip of the receiving frame contacts the outer step portion.

[0058] According to this configuration, when the concave side joint and the convex side joint are combined, the relative positions of the concave side joint and the convex side joint in the axial direction can be kept constant.

[0059] A sixth item disclosed in this specification is the duct joint according to the fifth item, wherein the outer stepped portion has an outer facing surface formed of an elastic material.

[0060] According to this configuration, the tip portion of the receiving frame and the outer facing surface of the outer step portion are in close contact with each other, making it possible to prevent fluid in the duct from leaking to the outside through the gap therebetween.

[0061] A seventh item disclosed in this specification is a duct fitting according to any one of the first to sixth items, which includes a locking member located on one of the concave side fitting and the convex side fitting, and a locked member located on the other of the concave side fitting and the convex side fitting, and which is provided with a fastener that limits axial movement of the convex side fitting relative to the concave side fitting when the concave side fitting and the convex side fitting are combined, by the locking member locking to the locked member.

[0062] According to this configuration, the movement of the convex side joint relative to the concave side joint in the axial direction is restricted, so that the concave side joint and the convex side joint can be maintained in an engaged state.

[0063] An eighth item disclosed in this specification is a duct fitting according to the first item, wherein the inner peripheral surface of the receiving frame is linear in a cross-sectional view including the axis of the receiving frame, and the outer peripheral surface of the insertion frame is linear in a cross-sectional view including the axis of the insertion frame.

[0064] According to this configuration, the receiving frame and the insertion frame can be easily processed.

[0065] A ninth item disclosed in this specification is the duct fitting according to the eighth item, wherein the angle of inclination of the receiving frame formed by the inner peripheral surface of the receiving frame and the axis of the receiving frame in a cross-sectional view including the axis of the receiving frame is smaller than the angle of inclination of the inserting frame formed by the outer peripheral surface of the inserting frame and the axis of the inserting frame in a cross-sectional view including the axis of the inserting frame.

[0066] According to this configuration, the concave side joint and the convex side joint can be easily combined and separated.

[0067] A tenth item disclosed in the present specification is the duct joint according to the ninth item, in which the insertion frame inclination angle is 1 degree or less.

[0068] According to this configuration, the concave side joint and the convex side joint can be easily combined and separated.

[0069] An eleventh item disclosed in this specification is a duct fitting according to the second item, wherein the inner peripheral surface of the receiving frame is linear in a cross-sectional view including the axis of the receiving frame, and the outer peripheral surface of the insertion frame is linear in a cross-sectional view including the axis of the insertion frame.

[0070] According to this configuration, the receiving frame and the insertion frame can be easily processed.

[0071] A twelfth item disclosed in this specification is a duct fitting according to the eleventh item, wherein the angle of inclination of the receiving frame formed by the inner peripheral surface of the receiving frame and the axis of the receiving frame in a cross-sectional view including the axis of the receiving frame is greater than the angle of inclination of the inserting frame formed by the outer peripheral surface of the inserting frame and the axis of the inserting frame in a cross-sectional view including the axis of the inserting frame.

[0072] According to this configuration, the concave side joint and the convex side joint can be easily combined and separated.

[0073] A thirteenth item disclosed in the present specification is the duct joint according to the twelfth item, in which the frame inclination angle is 1 degree or less.

[0074] According to this configuration, the concave side joint and the convex side joint can be easily combined and separated.

[0075] The fourteenth item disclosed in this specification is a duct fitting according to the first or second item, wherein the shape and size of the inner peripheral edge of the concave side fitting when viewed from the axial direction of the receiving frame are the same as the shape and size of the inner peripheral edge of the convex side fitting when viewed from the axial direction of the insertion frame.

[0076] According to this configuration, flow resistance at the boundary between the concave side joint and the convex side joint can be reduced. [Explanation of symbols]

[0077] 10 Concave side joint 11 Receiving slot 12 Inner step part 13 axis 14 Inner surface 16 Inner facing surface 20 Convex side joint 21 Insert frame 22 Outside step part 23 Axis center 24 Outer surface 26 Outward facing surface 30 Fasteners 31 Locking member 32 Locked member 100 Duct fittings 101 Duct 102 Duct

Claims

1. a concave-side joint including a frame-shaped receiving frame on an outer periphery thereof; A convex-side joint including a frame-shaped insertion frame that is inserted into the receiving frame at an outer periphery and that is combined with the concave-side joint, the inner peripheral surface of the receiving frame is parallel to the axis of the receiving frame or is inclined so as to move away from the axis of the receiving frame toward the tip, A duct joint, wherein the outer peripheral surface of the insertion frame is inclined so as to approach the axis of the insertion frame toward the tip.

2. a concave-side joint including a frame-shaped receiving frame on an outer periphery thereof; A convex-side joint including a frame-shaped insertion frame that is inserted into the receiving frame at an outer periphery and that is combined with the concave-side joint, The inner peripheral surface of the receiving frame is inclined so as to move away from the axis of the receiving frame toward the tip, A duct joint, wherein the outer peripheral surface of the insertion frame is parallel to the axis of the insertion frame or is inclined so as to approach the axis of the insertion frame toward the tip.

3. the concave-side joint includes an inner step portion located on the inner peripheral side of the receiving frame, The duct joint according to claim 1 or 2, wherein a tip of the insertion frame contacts the inner step portion when the concave side joint and the convex side joint are combined.

4. 4. The duct coupling according to claim 3, wherein said inner step portion has an inner facing surface formed of a resilient material.

5. the convex-side joint includes an outer step portion located on the outer peripheral side of the insertion frame, The duct joint according to claim 1 or 2, wherein a tip of the receiving frame contacts the outer stepped portion when the concave side joint and the convex side joint are combined.

6. 6. The duct coupling according to claim 5, wherein said outer step portion has an outer facing surface formed of a resilient material.

7. 3. A duct fitting according to claim 1 or 2, comprising: a locking member located on one of the concave side fitting and the convex side fitting; and a locked member located on the other of the concave side fitting and the convex side fitting, wherein, when the concave side fitting and the convex side fitting are combined, the locking member locks onto the locked member, thereby providing a fastener that limits axial movement of the convex side fitting relative to the concave side fitting.

8. an inner peripheral surface of the receiving frame is linear in a cross section including an axis of the receiving frame; The duct joint according to claim 1 , wherein an outer peripheral surface of the insertion frame is linear in a cross section including an axis of the insertion frame.

9. The duct joint according to claim 8, wherein the angle of inclination of the receiving frame formed by the inner surface of the receiving frame and the axis of the receiving frame in a cross-sectional view including the axis of the receiving frame is smaller than the angle of inclination of the receiving frame formed by the outer surface of the insertion frame and the axis of the insertion frame in a cross-sectional view including the axis of the insertion frame.

10. 10. The duct fitting of claim 9, wherein the insert frame tilt angle is 1 degree or less.

11. an inner peripheral surface of the receiving frame is linear in a cross section including an axis of the receiving frame; The duct joint according to claim 2 , wherein the outer peripheral surface of the insertion frame is linear in a cross section including an axis of the insertion frame.

12. The duct joint according to claim 11, wherein a receiving frame inclination angle formed by the inner surface of the receiving frame and the axis of the receiving frame in a cross-sectional view including the axis of the receiving frame is greater than a receiving frame inclination angle formed by the outer surface of the insertion frame and the axis of the insertion frame in a cross-sectional view including the axis of the insertion frame.

13. 13. The duct joint of claim 12, wherein the frame tilt angle is 1 degree or less.

14. The duct joint according to claim 1 or 2, wherein the shape and size of the inner peripheral edge of the concave side joint when viewed from the axial direction of the receiving frame are the same as the shape and size of the inner peripheral edge of the convex side joint when viewed from the axial direction of the insertion frame.

Images