Inner cover for flexible duct and manufacturing method thereof

Abstract

To provide an inner cover for a flexible duct capable of reducing a diameter without using another member such as a chamber, and a manufacturing method thereof.SOLUTION: The present invention is a cylindrical inner cover 1 for a flexible duct, which has a retaining part 4 in which edge parts 5, 5 of strips 3 stacked in a spiral manner are caulked and fastened. The inner cover 1 forms a reduced diameter part 6 formed so that the retaining part 4 protrudes in an axial direction of the spiral. The reduced diameter part 6 can reduce a diameter without using another member such as a chamber.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inner covering for a flexible duct, in which a spiral body made of nonwoven fabric or the like is crimped with a fastener to fix it into a cylindrical shape. [Background technology]

[0002] Conventionally, flexible ducts made of nonwoven fabric have been used as air conditioning ducts. One such flexible duct is manufactured by overlapping the edges of the duct, spirally winding the nonwoven fabric, and fixing it into a cylindrical shape with a crimped part at a fastening part, according to the manufacturing method shown in Patent Document 1. In a flexible duct manufactured by this manufacturing method, both overlapping edges are located on the outer surface side of the duct, and do not form internal fins, thereby reducing the resistance of the air flowing inside the duct. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-049401 A Summary of the Invention [Problem to be solved by the invention]

[0004] Air conditioning ducts made of flexible ducts are used by connecting them to air outlets, ducts, chambers, etc. When connecting to existing air outlets, the inner diameter of the existing object and the inner diameter of the air conditioning duct (diameter of the flexible duct) may differ, and in order to connect them, it is necessary to use a joint with an end that corresponds to both diameters. If the difference between the two diameters is large, the diameter will fluctuate greatly over a short distance in the flow direction (axial direction of the joint), which will increase the pressure loss at the connection part (joint), requiring a large, high-power blower. In addition, if a joint with a large difference in diameter (diameter fluctuation) is used, it is more likely to cause vibration and noise due to increased air resistance, which is one of the causes of pressure loss.

[0005] Therefore, an object of the present invention is to provide an inner casing for a flexible duct that can be reduced in diameter without using a separate component such as a chamber, and a method for manufacturing the same. [Means for solving the problem]

[0006] The present invention Inner casing for flexible duct In view of the above problem, a spirally stacked strip is overlap The edge of the casing is crimped to have a fastening portion, Has a longitudinal direction Cylindrical Within of the subject In the inner covering used for a flexible duct, the outer surface of which is wrapped with glass wool and then wrapped with an outer covering, The inner cover has the retaining portion. The bent shape is formed so as to protrude from the helical direction toward the longitudinal direction of the inner cover, which is the axial direction of the helix. It is characterized by the formation of a reduced diameter portion.

[0007] In addition, it is preferable that the reduced diameter portion formed to protrude toward the longitudinal direction of the inner jacket has a convex shape consisting of two protruding sides in the protruding direction and a tip side connecting the two protruding sides and having a predetermined length toward the spiral direction of the reduced diameter portion.

[0008] Furthermore, it is preferable that the two protruding sides have two first bent portions that bend around a spiral circle on one side and two second bent portions that form a tip side from the protruding side on the other side, and that the two protruding sides each consist of an inclined side that inclines toward the center so that the distance between the second bent portions is shorter than the length between the first bent portions.

[0009] Also, The present invention A method for manufacturing an inner cover for a flexible duct teeth, The inner covering is used for a flexible duct, which is formed by winding glass wool around the outer surface of a cylindrical inner covering having a longitudinal direction, and further winding an outer covering around the inner covering, and has a fastening portion formed by crimping the overlapping edges of a spirally overlapping strip, A method for reducing the diameter of a cylindrical inner jacket for a flexible duct, comprising the steps of: A wire and a steel material are arranged on the edge of the spirally overlapped strip, and the wire and the steel material are crimped together to form a fastening portion. Before wrapping the glass wool and outer shell to complete the flexible duct an inner casing manufacturing process for forming an inner casing for a cylindrical flexible duct; The inner shell manufactured in the inner shell manufacturing process outer surface From this, while supporting the circular periphery of the fastener , place A constant width pressing surface At the tipand a reduced diameter portion forming step of forming a convex reduced diameter portion by pressing a pressing tool having a convex shape. Effect of the Invention

[0010] According to the invention described in claim 1, it is possible to provide an inner casing for a flexible duct in which the diameter is gradually and gently changed and pressure loss is suppressed by forming a narrow diameter portion by protruding and deforming the retaining portion. Furthermore, it is possible to form the narrow diameter portion after completing the inner casing, and it is possible to provide an inner casing for a flexible duct that can be individually adapted according to the installation situation.

[0011] According to the invention described in claim 2, by making the shape of the reduced diameter portion a convex body, the tip edge is in the same direction as the spirally formed circular periphery, thereby reducing pressure loss during air blowing and providing an inner covering for a flexible duct that is unlikely to affect the ventilation inside the duct even if the reduced diameter portion is present.

[0012] According to the invention described in claim 3, it is possible to provide an inner casing for a flexible duct that is less prone to damage by reducing the load applied to the band-shaped body through the formation of a reduced diameter portion.

[0013] According to the invention described in claim 4, it is possible to easily form a reduced diameter portion that can reduce the diameter of the inner covering for flexible duct of the present invention. That is, while it was extremely difficult to reduce the diameter of the duct itself in the past, it is now possible to form the reduced diameter portion from the outside after the inner covering is once completed, making it possible to provide a duct with a reduced diameter easily and in a mass-produced manner. [Brief description of the drawings]

[0014] [Figure 1] 1 is a side view of an inner cover for a flexible duct according to an embodiment of the present invention. [Diagram 2] 2 is a partially enlarged side view of the periphery of a reduced diameter portion, in which a region A in FIG. 1 is enlarged. [Diagram 3] FIG. 2 is a perspective view of a processing device for manufacturing the reduced diameter portion of the present invention. [Figure 4]FIG. 2 is a front view of a processing device for manufacturing a reduced diameter portion of the present invention. [Diagram 5] FIG. 2 is a perspective view showing a state in which an inner housing is set in the processing device. [Figure 6] 5A and 5B are partially enlarged front views showing a state in which a reduced diameter portion is manufactured by a processing device, in which (a) shows the state before processing and (b) shows the state after processing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment, and various modifications, additions, etc. are possible within the scope of the gist of the present invention. In this embodiment, the longitudinal direction of the inner jacket 1 (the axial direction of the spiral) is defined as the longitudinal direction of the inner jacket, and the direction in which the retaining portion 4 spirals around the surface of the inner jacket 1 is defined as the spiral direction. In particular, the spiral direction of the reduced diameter portion 6 is defined as the direction in which the retaining portion 4 was originally spiraling at the position of the reduced diameter portion 6.

[0016] The inner covering 1 for flexible duct of the present invention is used as the inner core of a flexible duct used as an air conditioning duct. Although not shown, the completed flexible duct is molded by wrapping glass wool around the outer surface of the inner covering 1 for flexible duct and further wrapping an outer covering made of an olefin resin around it. As shown in Fig. 1, the inner covering 1 of this embodiment is basically composed of a band 3 wound in a hollow spiral shape and a fastener 4 for fixing the edges 5, 5 where the bands 3, 3 overlap.

[0017] The strip 3 forms the wall surface of the cylindrical inner cover 1 and is made of a strip of a specified width with a base material of nonwoven fabric, cloth, or paper coated with a synthetic resin. The strip 3 is wound spirally with the edges 5, 5 overlapping each other to form a cylindrical shape. The strip 3 is made of a film or sheet so that the cross section of the wound cylinder is circular.

[0018] The overlapping edge portions 5, 5 of the strip 3 are held by the fastening portion 4 and fixed into a cylindrical shape. The fastening portion 4 is made of a thin metal sheet and a steel wire-like core material (not shown) that abuts against the outer periphery of the strip 3 and is wound spirally along the edge portions 5, 5. The wire (core material) is placed along the edge portions 5, 5, and the thin metal sheet is overlapped on the inside. Both edge portions 5, 5 are clamped and fixed in place by a crimping process in which the core material prevents them from slipping out and the core material is used to bend them inward to form a C-shape.

[0019] In the crimping process of the fastening portion 4, the edges 5, 5 of the band 3 are folded back to the outer surface side of the duct and overlapped with the outer (outer surface) edge 5 of the inner covering 1, so that both edges 5, 5 are disposed on the outer surface side of the inner covering 1. The part where the two edges 5, 5 are overlapped and protrude slightly to the outer surface side is called a fin. In another embodiment, the crimping process may be performed so that the edges 5, 5 (fins) protrude to the inside of the inner covering 1.

[0020] As shown in FIG. 1, the retaining portion 4 has one or more reduced diameter portions 6, 6 formed on the outer periphery at a predetermined interval in the spiral direction. The reduced diameter portion 6 is formed by bending the retaining portion 4 that has been crimped (subjected to a crimping process) so as to protrude convexly toward the inner jacket longitudinal direction, which is the longitudinal direction of the inner jacket 1. In this embodiment, the direction in which the reduced diameter portion protrudes toward the inner jacket longitudinal direction to be convex is made to coincide with the protruding direction of the edge portions 5, 5 (fins) located outward from the retaining portion 4. This coincidence reduces pressure loss and makes the inner jacket less likely to break. Being convex in the axial direction of this spiral means that the protruding direction of the inner jacket 1, which has a circular shape having a longitudinal direction, is made to coincide with the longitudinal direction.

[0021] By forming a portion of the spiral fastening portion 4 with a reduced diameter portion 6 so that it is convex in one direction, the band-shaped body 3 that is crimped and held by the fastening portion 4 is also deformed. In this deformation, the circumference of the inner jacket 1 shrinks, reducing its diameter. By arranging multiple identical reduced diameter portions 6 in the spiral direction, the inner jacket 1 is reduced in diameter according to the number of arranged portions, so that by gradually narrowing the spacing (number) between the arranged portions, it becomes a spiral shape with a gradually reduced diameter. By arranging the reduced diameter portions 6 at equal intervals, it becomes a spiral shape that maintains the reduced diameter dimension.

[0022] In this embodiment, the convex protruding direction of the reduced diameter portion 6 is the same as the outward protruding direction of the edge portions 5, 5 (fins), and the convex tip portion of the reduced diameter portion 6 is straight (tip edge 8 described below) so as to follow the spiral direction of the reduced diameter portion.

[0023] In order to explain the specific form of the reduced diameter portion 6, FIG. 2 shows a partially enlarged view of only the reduced diameter portion 6. The retaining portion 4 has a circular periphery 4a that forms a spiral circumference of the duct, a pair of first bent portions 9, 9 that bend this circular periphery 4a, a pair of protruding sides 7, 7 that extend from the first bent portions 9, 9 in the longitudinal direction of the inner casing, a pair of second bent portions 10, 10 that are bent from the tip portions of the protruding sides 7, 7 to face each other, and a tip side 8 that extends in a straight line shape along the spiral from both second bent portions 10, 10 and connects both protruding sides 7, 7. The tip side 8 has a predetermined length that extends in the spiral direction of the reduced diameter portion. Note that the protruding direction of the reduced diameter portion 6 is formed in the longitudinal direction of the inner casing, and the tip side 8 is formed in the spiral direction of the reduced diameter portion 6, and these directions are not strictly the same, but include a certain error, etc.

[0024] The protruding sides 7, 7 are straight lines extending at a slight inward incline from the longitudinal direction of the inner jacket, and each of the protruding sides 6, 6 on both sides constituting one reduced diameter section 6 is formed as an inclined side inclined toward the center. The protruding sides 7, 7 have a length dimension of about 20 mm toward the tip side 8. The length dimension of the tip side 8 is about 10 mm. The protruding length of the protruding sides 7, 7 is about one-quarter of the pitch of the spiral (see Figure 1).

[0025] The protruding sides 7, 7 are inclined toward each other toward the center so that the distance X2 between the two second bent portions 10, 10 is shorter than the distance X1 between the two first bent portions 9, 9. In this manner, the reduced diameter portion 6 of this embodiment is formed in a trapezoidal shape. Note that, in other embodiments, the protruding sides 7, 7 may have a shape in which the tip side 8 is curved from the tip side of the protruding sides 7, 7, or the first bent portions 9, 9 and the second bent portions 10, 10 may be curved relatively greatly.

[0026] By having the protruding sides 7, 7 inclined toward each other toward the center, the fins formed on the edges 5, 5 by molding the reduced diameter portion 6 are prevented from being pulled in or coming off the crimped fastening portion. Also, when ventilation is passed through the duct, the bent portion is not bent at a right angle to prevent pressure from concentrating in one area.

[0027] Next, the processing device 20 for forming the reduced diameter portion 6 in the inner housing 1 will be described with reference to the drawings.

[0028] 3, the processing device 20 comprises a holder 21 that holds the retaining portion 4, a pressing tool 22 made of a long rod plate that rotates by the principle of a lever to appear and disappear from the holder 21, and a drive unit 23 that rotates the pressing tool 22. The processing device 20 presses a part of the retaining portion 4 held on the holder 21 with the pressing tool 22 to perform bending processing to form the reduced diameter portion 6, thereby reducing the diameter of the inner jacket 1. The drive unit 23 is a well-known drive means, and in this embodiment comprises an air piston, but is not particularly limited and may be a hydraulic piston, a motor-driven crank, or the like.

[0029] The pressing tool 22 has one end in the longitudinal direction connected to the driving part 23, a pressing part 24 protruding downward at the other end, and a support part 26 supported by a support shaft 25 that protrudes downward at the middle part in the longitudinal direction and serves as a fulcrum of the lever, forming an F-shape. The pressing part 24 has a pressing surface with a predetermined length in the width direction at its tip, and can be moved up and down by the driving part 23 at the other end.

[0030] The holding table 21 is made up of an upper plate 27 and a lower plate 28 that are parallel to each other, and the plate surface of the upper plate 27 is disposed perpendicular to the moving direction of the pressing part 24. As shown in Fig. 4, the holding table 21 has a guide slit 30 formed between the upper and lower plates 27, 28 and opening to the front and in the width direction of the lower plate 28, and a processed groove 31 formed in the center of the width direction of the lower plate 28 and opening to the front and above and below perpendicular to the plate surface.

[0031] 5 and 6, the guide slit 30 has a vertical dimension that is approximately the same as the length of the fastening portion 4 plus the thickness of the strip 3. The guide slit 30 supports the fastening portion 4 in the processing position from above and below by inserting the fastening portion 4 from the front side.

[0032] The processed groove 31 is formed perpendicular to the guide slit 30, penetrating the upper plate 27 and the lower plate 28, allowing the pressing part 24 to move up and down. The processed groove 31 consists of an upper part 33 formed on the upper plate 27 side and a lower part 34 formed on the lower plate 28 side. The width dimension of the upper part 33 is approximately the same as or slightly longer than the width dimension of the pressing part 24, allowing the pressing part 24 to move freely without contacting the upper part 33.

[0033] The lower part 34 has a width dimension greater than that of the upper part 33, and has wide gaps S between it and both plate surfaces (on both the left and right sides) of the moving pressing part 24 (see FIG. 6). The width dimensions of the left and right gaps S are approximately the same as the vertical dimensions of the guide slit 30, making it possible to accommodate the fastening part 4 and the strip 3 (reduced diameter part 6) during processing.

[0034] The pressing portion 24 is located at the upper portion 33 of the machining groove 31 in an unloaded state, and when the pressing tool 22 is rotated by the driving portion 23, it crosses the guide slit 30, and when it rotates further, it descends to a position at the lower portion 34. When the pressing portion 24 is in a fully loaded state after rotating the farthest, its lower end portion is located lower than the upper surface of the lower plate 28.

[0035] Next, a method for manufacturing the inner jacket 1 of this embodiment will be described. First, a general inner jacket 1 is manufactured. The inner jacket 1 is manufactured by spirally winding the strips 3, 3 while overlapping the edge portions 5, 5, using a dedicated manufacturing machine called a mandrel. At this time, a wire is placed along one surface of the overlapped edge portions 5, 5, and a metal sheet that will become the outer surface of the fastening portion 4 is placed along the other surface. The metal sheet is then bent to narrow the width, and is shaped and crimped to embrace the edge portions 5, 5 and the wire. In this manner, a general cylindrical inner jacket 1 is completed.

[0036] The processing device 20 described above is used to form the reduced diameter portion 6 of the inner covering 1. First, as shown in Fig. 5, the fastening portion 4 (circular periphery 4a) is inserted into the guide slit 30 of the processing device 20. In this manner, the fastening portion 4 of the inner covering 1 protrudes slightly from the outer surface of the wrapped strips 3, 3, and the strip 3 is made of a relatively soft material, so that it is possible to insert it into the guide slit 30.

[0037] 6(a) and 6(b), by inserting the fastening portion 4 into the guide slit 30, a reduced diameter portion 6 is formed in the portion crossing the machined groove 31, and the guide slit inserted portion other than the machined groove 31 (circular periphery 4a) is held by the upper plate 27 and the lower plate 28. In this state, by rotating the pressing tool 22 with the driving portion 23 to lower the pressing portion 24, the circular periphery 4a is bent so that first bent portions 9, 9 and second bent portions 10, 10 are formed, and a trapezoidal reduced diameter portion 6 having protruding sides 7, 7 and a tip side 8 can be formed.

[0038] A flexible duct with a reduced diameter can be manufactured by wrapping glass wool and an outer skin around the reduced-diameter inner casing 1 manufactured in this manner. Note that the above manufacturing method allows the reduced-diameter portions 6, 6 to be manufactured from the outside of the inner casing 1 as appropriate, so it is also possible to manufacture an inner casing 1 that is first reduced in diameter and then expanded in diameter. In this case, it is also possible to manufacture an inner casing with a maximum diameter, and then form a number of gradually reduced-diameter portions in multiple places, making it possible to manufacture a flexible duct with a complexly changing diameter.

[0039] In addition, each of the reduced diameter portions 6, 6 in this embodiment reduces the inner jacket 1 by approximately 19.5 mm in the circumferential direction. The diameter (center diameter) of the inner jacket 1 is often manufactured in increments of 50 mm, and there are types of 150, 200, 250, 300, and 350. For example, the spiral length (inner diameter circumference) of the retaining portion 4 with a center diameter of 150 mm is 502.4 mm, and the spiral length (target circumference) of one turn when the center diameter after the diameter reduction is to be 100 mm is 345.4 mm. The difference is 157 mm, and if eight reduced diameter portions 6, 6 that reduce 19.5 mm are formed, the diameter can be reduced by 50 mm. When the other types were calculated, as shown in Table 1 below, if eight reduced diameter portions 6, 6 that reduce 19.5 mm are formed, the diameter can be reduced by 50 mm. Therefore, it is possible to provide an inner jacket 1 for flexible ducts that can reduce the predetermined diameter with a simple configuration and method.

[0040] [Table 1] [Explanation of symbols]

[0041] 1...inner covering for flexible duct, 3...belt-shaped body, 4...fastening portion, 4a...circular periphery, 5...edge portion, 6...reduced diameter portion, 7...protruding edge, 8...tip edge, 9...first bent portion, 10...second bent portion.

Claims

1. The inner covering is used for a flexible duct, which is formed by winding glass wool around the outer surface of a cylindrical inner covering having a longitudinal direction, and further winding an outer covering around the inner covering, and has a fastening portion formed by crimping the overlapping edges of a spirally overlapping strip, The inner casing for a flexible duct is characterized in that the inner casing has a reduced diameter portion formed by bending the fastening portion so as to protrude from the spiral direction toward the longitudinal direction of the inner casing, which is the axial direction of the spiral.

2. The inner duct for flexible duct as described in claim 1, characterized in that the reduced diameter portion formed to protrude toward the longitudinal direction of the inner duct has a convex shape consisting of two protruding sides in the protruding direction and a tip side connecting the two protruding sides and having a predetermined length toward the spiral direction of the reduced diameter portion.

3. The two protruding sides have two first bending portions that bend around a spiral circle on one side, and two second bending portions that form a tip side from the protruding side on the other side, The inner covering for a flexible duct as described in claim 2, characterized in that the two protruding sides each consist of an inclined side that inclines toward the center so that the distance between the second bent portions is shorter than the length between the first bent portions.

4. In a flexible duct formed by winding glass wool around the outer surface of a cylindrical inner covering having a longitudinal direction and further winding an outer covering around the inner covering, the inner covering is used for a flexible duct, the inner covering having a fastening portion formed by crimping the overlapping edges of overlapping strips overlapped in a spiral shape, A method for reducing the diameter of a cylindrical inner jacket for a flexible duct, comprising the steps of: an inner cover manufacturing process in which a wire and a steel material are arranged on the edge of the spirally overlapped strip, and the wire and the steel material are crimped together to form a fastening portion, and then a glass wool and an outer cover are wound around the wire and the steel material to form a cylindrical inner cover for a flexible duct before the flexible duct is completed; a reduced diameter portion forming process for forming a convex reduced diameter portion by pressing a pressing tool having a pressing surface of a predetermined width at its tip against the outer surface of the inner covering manufactured in the inner covering manufacturing process while supporting the circular periphery of the fastening portion.

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