Air blower pipeline

Abstract

The utility model provides an air blower pipeline which simplifies the shape of a connecting part of the pipeline, can reliably connect two pipelines and can reduce manufacturing cost. In a blower duct (2), a circumferential restriction groove (20) and an axial restriction groove (30) are formed in an intermediate duct (2B). A first protrusion (60) and a second protrusion (70) are formed on the outer peripheral surface of the base pipe (2A). The base pipe (2A) and the intermediate pipe (2B) are connected in a state in which the base end opening of the intermediate pipe (2B) is inserted into the tip end of the base pipe (2A), the first protrusion (60) engages with the circumferential direction regulating groove (20) in the circumferential direction of the intermediate pipe (2B), and the second protrusion (70) engages with the axial direction regulating groove (30) in the axial direction of the intermediate pipe (2B).

Description

TECHNICAL FIELD

[0001] The utility model relates to the air blower pipeline. BACKGROUND

[0002] In a power blower (air blower) for performing a cleaning operation of fallen leaves and dust, an air blower pipeline is connected to a discharge port formed in a housing in order to discharge a high-speed air stream blown from the discharge port to a desired position. The air blower pipeline is configured to have a desired length by connecting a plurality of pipelines.

[0003] An example of a connection structure of a front end portion of the second pipeline to the first pipeline in the air blower pipeline is described.

[0004] A groove portion extending in the circumferential direction is formed in the inner peripheral surface of the second pipeline, and a concave-convex surface is formed in the inner surface of the groove portion. In addition, a protrusion portion is formed in the outer peripheral surface of the front end portion of the first pipeline.

[0005] When connecting the two pipelines, the front end portion of the first pipeline is inserted into the base end opening portion of the second pipeline, and the second pipeline is rotated with respect to the first pipeline in the circumferential direction. In this way, the protrusion portion of the first pipeline enters the groove portion of the second pipeline, and the front end portion of the first pipeline abuts against the reduced diameter portion of the inner peripheral surface of the second pipeline.

[0006] Furthermore, the front end portion of the first pipeline abuts against the reduced diameter portion of the second pipeline, and the protrusion portion of the first pipeline is engaged with the groove portion of the second pipeline, thereby restricting the movement of the two pipelines in the axial direction. In addition, the protrusion portion of the first pipeline is engaged with the concave-convex surface of the groove portion of the second pipeline, thereby restricting the movement of the two pipelines in the circumferential direction. In this way, the movement of the two pipelines in the axial direction and the circumferential direction is restricted, thereby connecting the two pipelines (for example, U.S. Patent No. 8210577).

[0007] In the above connection structure, a plurality of groove portions are arranged in the axial direction of the second pipeline. That is, a plurality of stages of groove portions are formed in the axial direction, and a plurality of concave-convex portions are formed in the circumferential direction of each groove portion. In this way, a plurality of groove portions and concave-convex portions are arranged in the axial direction and the circumferential direction of the pipeline, so that even if there is a dimensional error in the axial direction or the radial direction of the pipeline, the protrusion portion of the first pipeline can enter the groove portion of any one of the second pipelines, and the two pipelines can be connected.

[0008] On the other hand, in the above connection structure, in addition to the fact that the shape of the connection portion of the second pipeline becomes complex, the connection structure exists at a position spaced apart from the end portions of the pipelines, so it is difficult to select injection molding as the manufacturing method of the pipelines, and blow molding is selected instead. In this way, the structure of the mold for manufacturing the pipelines becomes complex, so not only does this directly affect the cost, but the selection options for the manufacturing method of the pipelines are narrowed, thereby limiting the reduction of manufacturing costs. Utility model content

[0009] The utility model discloses a blower pipe which can solve the above problems, reliably connect two pipes while simplifying the connection structure of the pipes, and reduce manufacturing cost.

[0010] In order to solve the above problems, the utility model discloses a blower pipe connected with the air outlet of the power blower, which comprises a first pipe and a second pipe connected with the front end of the first pipe. A circumferential limiting groove and an axial limiting groove are formed in the second pipe. A first protrusion is formed on the outer circumferential surface of the first pipe and inserted into the circumferential limiting groove. A second protrusion is formed on the outer circumferential surface of the first pipe and inserted into the axial limiting groove. The first pipe is connected with the second pipe in the state that the first protrusion is engaged with the circumferential limiting groove in the circumferential direction of the second pipe and the second protrusion is engaged with the axial limiting groove in the axial direction of the second pipe.

[0011] Compared with the prior art, the utility model can achieve at least one of the following beneficial effects:

[0012] In the blower pipe of the utility model, circumferential limiting portions and axial limiting portions are respectively arranged in the connection structure of the first pipe and the second pipe, so that the connection structure can be miniaturized and simplified. In the connected state of the first pipe and the second pipe, the second protrusion is engaged with the axial limiting groove, so that the movement of the two pipes in the axial direction is limited. In addition, the first protrusion is engaged with the circumferential limiting groove, so that the movement of the two pipes in the circumferential direction is limited.

[0013] In the blower pipe of the utility model, the movement of the two pipes in the axial direction is limited by the axial limiting groove, so that the structure of the circumferential limiting groove can be simplified. In addition, in the blower pipe of the utility model, multiple circumferential limiting grooves do not need to be arranged in the axial direction. By extending one circumferential limiting groove in the axial direction, the dimensional error of the pipe in the axial direction can be addressed. Therefore, the connection structure of the pipe can be simplified, and the manufacturing ease of the pipe is also ensured.

[0014] In the blower pipe of the utility model, the connection structure of the pipe is simplified while considering the dimensional error of the pipe, and the two pipes can be reliably connected. Therefore, in the utility model, the pipe is easy to form, so that the manufacturing cost of the blower pipe can be reduced.

[0015] For example, in the blower duct of the present application, the structure of the mold for injection molding the duct is simplified, and thus the duct can be manufactured by injection molding. In this way, the selection of the molding method of the duct is wider, and a lower cost manufacturing method can be selected. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 is a perspective view showing a power blower to which a blower duct according to an embodiment of the present application is attached.

[0017] Figure 2 FIG. 2 is a view showing a connection structure of the blower duct according to the embodiment of the present application, and is also a perspective view showing a state in which two ducts are connected from a front end side.

[0018] Figure 3 FIG. 3 is a view showing a connection structure of the blower duct according to the embodiment of the present application, and is also a perspective view showing a state before two ducts are connected from a front end side.

[0019] Figure 4 FIG. 4 is a view showing a connection structure of the blower duct according to the embodiment of the present application, and is also a perspective view showing a state before two ducts are connected from a base end side.

[0020] Figure 5 FIG. 5 is a view showing a connection structure of the blower duct according to the embodiment of the present application, and is also a side view showing a state before two ducts are connected.

[0021] Figure 6 FIG. 6 is a view showing a connection structure of the blower duct according to another embodiment of the present application, and is also a side view showing a state before two ducts are connected.

[0022] REFERENCE NUMERALS:

[0023] 1 - power blower; 1a - housing; 1b - air outlet; 2 - blower duct; 2A - base duct; 2B - intermediate duct; 2C - front end duct; 2D - air outlet; 2E - flexible portion; 10 - reduced diameter portion; 20 - circumferential restriction groove portion; 20a - first end portion; 20b - second end portion; 21 - concave-convex surface; 3 - connection portion; 30 - axial restriction groove portion; 30a - third end portion; 30b - fourth end portion; 31 - inclined edge portion; 40 - insertion groove portion; 50 - abutment portion; 51 - protrusion; 60 - first protrusion portion; 70 - second protrusion portion; S - slit. DETAILED DESCRIPTION

[0024] The embodiments of the present application are explained in detail with appropriate reference to the accompanying drawings.

[0025] As Figure 1As shown, in this embodiment, the blower pipe 2 is installed on the power blower 1 (blower).

[0026] The powered blower 1 generates an airflow within the housing 1a by rotating a fan (not shown) housed inside the housing 1a using a power source such as an engine or motor (not shown). An outlet 1b for discharging the airflow is formed within the housing 1a, and a blower duct 2 is connected to the outlet 1b. Furthermore, by blowing the airflow to the ground from the front end of the blower duct 2, fallen leaves or dust can be blown away.

[0027] In this embodiment, the blower duct 2 is formed to the desired length by connecting the three ducts: the base duct 2A, the intermediate duct 2B, and the front duct 2C.

[0028] Generally speaking, for Figure 1 As shown, the backpack-type powered blower 1 has a relatively large distance between its outer casing 1a (blower) and the ground, so three pipes are connected together. Conversely, for a handheld powered blower, the distance between the outer casing (blower) and the ground is shorter, so two pipes are connected together. However, even with the backpack-type powered blower 1, if it is desired to use the outlet 2D located at the front end of the blower pipe 2 separately from the ground, sometimes the third pipe is not used, and two pipes are connected together instead. The operator should choose appropriately based on the work site.

[0029] The base pipe 2A is a cylindrical resin component whose base end is detachably connected to the outlet 1b of the outer casing 1a. At the base of the base pipe 2A, a corrugated section that can be freely bent radially is connected. The operator utilizes the flexibility of the corrugated section to swing the blower pipe 2, which is closer to the front end of the corrugated section, in a direction suitable for operation. The base end of the intermediate pipe 2B is connected to the front end of the base pipe 2A.

[0030] The intermediate pipe 2B is a cylindrical component made of resin. The base end of the front pipe 2C is connected to the front end of the intermediate pipe 2B.

[0031] The front-end pipe 2C is a cylindrical component made of resin. An air outlet 2D is formed at the front end of the front-end pipe 2C.

[0032] The connection structure between the base pipe 2A and the intermediate pipe 2B is the same as the connection structure between the intermediate pipe 2B and the front pipe 2C.

[0033] In the connection structure between the base pipe 2A and the intermediate pipe 2B, the base pipe 2A is equivalent to the "first pipe" in the claims, and the intermediate pipe 2B is equivalent to the "second pipe" in the claims.

[0034] Furthermore, in the connection structure between the intermediate pipe 2B and the front pipe 2C, the intermediate pipe 2B is equivalent to the "first pipe" in the claims, and the front pipe 2C is equivalent to the "second pipe" in the claims.

[0035] The following description explains the connection structure between the base pipe 2A and the intermediate pipe 2B, while the connection structure between the intermediate pipe 2B and the front pipe 2C is omitted.

[0036] In addition, in the following explanation, "axial" refers to the direction of extension of each pipe, and "circumferential" refers to the circumferential direction of each pipe.

[0037] like Figure 3 As shown, a reduced diameter portion 10 is formed on the inner circumferential surface of the base of the intermediate pipe 2B (second pipe). In this embodiment, the reduced diameter portion 10 is a tapered surface in which a portion of the inner circumferential surface of the base of the intermediate pipe 2B is reduced in diameter as it approaches the front end.

[0038] like Figure 4 As shown, in the intermediate pipe 2B, two connecting parts 3 are formed at a position closer to the base end than the reduced diameter section 10. These connecting parts are composed of a circumferential limiting groove 20, an axial limiting groove 30, and an insertion groove 40. The two connecting parts 3 are formed in a point-symmetric position and shape with the center point of the base end opening of the intermediate pipe 2B as the symmetry point.

[0039] A circumferential limiting groove 20 is disposed at the base end of the intermediate pipe 2B. The circumferential limiting groove 20 extends in the circumferential direction of the intermediate pipe 2B for a predetermined length, and extends axially in a predetermined length from the base end edge of the intermediate pipe 2B toward the front end side.

[0040] The circumferentially restricting groove 20 is a groove that is recessed radially outward from the inner circumferential surface of the intermediate pipe 2B.

[0041] In the circumferential limiting groove 20, the base end of the intermediate pipe 2B has a side opening. That is, the base end of the circumferential limiting groove 20 is open in the axial direction.

[0042] In this embodiment, two circumferential limiting grooves 20 are disposed on each half of the circumference of the intermediate pipe 2B.

[0043] Furthermore, an axial length of approximately 29 mm to 71.5 mm is sufficient for the connecting structure; in this embodiment, it is set to 42.5 mm. In conventional connecting structures, the axial length is 105.5 mm, therefore the connecting structure in this embodiment is significantly shorter.

[0044] like Figure 5As shown, the circumferential restriction groove portion 20 has an axial width that increases as it approaches the second end portion 20b from the first end portion 20a in the circumferential direction.

[0045] In the present embodiment, the axial width increases as it approaches the second end portion 20b from the first end portion 20a. Figure 5 As shown, the axial width of the circumferential restriction groove portion 20 increases as it approaches the second end portion 20b from the first end portion 20a in the circumferential direction. Figure 5 As shown, the axial width of the circumferential restriction groove portion 20 increases as it approaches the second end portion 20b from the first end portion 20a in the circumferential direction.

[0046] In the circumferential restriction groove portion 20, the edge portion on the front end side in the axial direction is inclined with respect to the circumferential direction of the intermediate pipe 2B (the up-down direction of the intermediate pipe 2B) in a manner that shifts from the base end side to the front end side of the intermediate pipe 2B (from the right side to the left side of the intermediate pipe 2B) as the first end portion 20a approaches the second end portion 20b. Figure 5 Figure 5 In the circumferential restriction groove portion 20, the edge portion on the front end side in the axial direction is inclined with respect to the circumferential direction of the intermediate pipe 2B (the up-down direction of the intermediate pipe 2B) in a manner that shifts from the base end side to the front end side of the intermediate pipe 2B (from the right side to the left side of the intermediate pipe 2B) as the first end portion 20a approaches the second end portion 20b.

[0047] When joining the intermediate pipe 2B to the base pipe 2A, the inclination of the edge portion on the front end side of the circumferential restriction groove portion 20 can be used to cause the intermediate pipe 2B to rotate in the circumferential direction with respect to the base pipe 2A while also advancing in the axial direction.

[0048] As shown, the axial width of the circumferential restriction groove portion 20 increases as it approaches the second end portion 20b from the first end portion 20a in the circumferential direction. Figure 4 As shown, the bottom surface of the circumferential restriction groove portion 20 (the inner surface on the radially outer side of the intermediate pipe 2B) is formed with a concave-convex surface 21 in which concavities and convexities are continuously formed in the circumferential direction.

[0049] With the concave-convex surface 21, a plurality of concave portions that are recessed with respect to the inner circumferential surface of the intermediate pipe 2B are formed in a row in the circumferential direction, and convex portions are formed between adjacent concave portions, so that the concavities and convexities are continuously maintained.

[0050] Here, with the concave-convex surface 21, the thickness of the bottom portion of the circumferential restriction groove portion 20 can be varied so as to be provided only on the inner surface, but by matching the concave-convex surface 21 of the inner surface of the intermediate pipe 2B, a concave-convex surface can also be provided on the outer surface, so that the thickness of the bottom portion of the circumferential restriction groove portion 20 can be made constant. Furthermore, when a concave-convex surface is also provided on the outer surface of the intermediate pipe 2B, the intermediate pipe 2B can be gripped by the concave-convex surface to be rotated, and the workability when joining the base pipe 2A to the intermediate pipe 2B can be improved.

[0051] The insertion groove portion 40 extends in the axial direction from the base end edge portion of the intermediate pipe 2B toward the front end side. The insertion groove portion 40 is a groove portion that is recessed with respect to the inner circumferential surface of the intermediate pipe 2B to the radially outer side of the intermediate pipe 2B.

[0052] In the insertion groove portion 40, the side portion on the base end side in the axial direction is open. That is, the base end portion of the insertion groove portion 40 is open in the axial direction so that the second protrusion portion 70 of the base pipe 2A described later enters from the base end side of the insertion groove portion 40.

[0053] As shown, the axial width of the circumferential restriction groove portion 20 increases as it approaches the second end portion 20b from the first end portion 20a in the circumferential direction. Figure 3 ​As shown, the insertion groove 40 is arranged circumferentially spaced from the first end 20a of the circumferential limiting groove 20. The insertion groove 40 is longer than the axial length of the circumferential limiting groove 20, and at its front end opposite to the axial base end side, the insertion groove 40 is connected to the axial limiting groove 30 (described later). That is, the insertion groove 40 is the part that connects the opening of the base end of the intermediate pipe 2B to the circumferential end of the axial limiting groove 30.

[0054] like Figure 5 As shown, the axial limiting groove 30 extends circumferentially along the intermediate pipe 2B. The axial limiting groove 30 is arranged side by side with respect to the circumferential limiting groove 20 on the axial front end side. The axial limiting groove 30 is an opening that penetrates from the outer circumferential surface of the intermediate pipe 2B to the inner circumferential surface.

[0055] The third end 30a of the axial limiting groove 30 is connected to the front end of the insertion groove 40, and the interior of the axial limiting groove 30 is in communication with the interior of the insertion groove 40.

[0056] The axially restricting groove 30 extends from the base end side to the front end side of the intermediate pipe 2B as it moves from the third end 30a to the fourth end 30b on the insertion groove 40 side. Figure 5 The displacement is from right to left, relative to the circumferential direction of the middle pipe 2B. Figure 5 (in the vertical direction) tilted.

[0057] At the axial base edge of the axial limiting groove 30 ( Figure 5 An inclined edge 31 is formed on the right side of the intermediate pipe 2B. The inclined edge 31 moves from one side (third end 30a side) to the other (fourth end 30b side) in the circumferential direction of the intermediate pipe 2B, towards the front end side of the intermediate pipe 2B. Figure 5 (on the left side) Stepped displacement. That is, multiple stepped sections are formed on the inclined edge 31.

[0058] A radial portion of the intermediate conduit 2B is formed at the inclined edge 31. Figure 5 Multiple straight sections extending in the vertical direction; and inclined sections formed between adjacent straight sections that are inclined relative to the straight sections.

[0059] like Figure 3 As shown, an abutment portion 50 is formed on the outer peripheral surface of the front end of the base pipe 2A (first pipe). The abutment portion 50 is formed by alternating recesses that are recessed throughout the entire circumference and protrusions that are protruding throughout the entire circumference in the axial direction.

[0060] like Figure 2As shown, when the front end of the base pipe 2A is inserted into the base end opening of the intermediate pipe 2B, each of the protrusions 51 on the outer peripheral surface of the abutting part 50 of the base pipe 2A abuts against the peripheral surface of the reduced diameter part 10 of the intermediate pipe 2B.

[0061] The outer peripheral surface of the abutment portion 50 has irregularities, resulting in a smaller contact area between the abutment portion 50 and the peripheral surface of the reduced-diameter portion 10. Therefore, during the insertion of the base pipe 2A relative to the intermediate pipe 2B, the front end of the base pipe 2A can be smoothly inserted into the intermediate pipe 2B. Furthermore, when the base pipe 2A is finally fixed relative to the intermediate pipe 2B, the protrusion 51 is pushed into the inner peripheral surface of the intermediate pipe 2B, thus stably connecting the intermediate pipe 2B and the base pipe 2A.

[0062] like Figure 3 As shown, on the outer peripheral surface of the base pipe 2A, a first protrusion 60 and a second protrusion 70 are formed at a position closer to the base end than the abutment portion 50.

[0063] Furthermore, although not shown in the figure, other first protrusions 60 and second protrusions 70 are also formed on the outer peripheral surface of the base pipe 2A at a point symmetrical with respect to the first protrusion 60 and second protrusion 70 shown in the figure, with the center point of the front opening of the base pipe 2A as the symmetrical point. That is, the first protrusions 60 and second protrusions 70 are provided in each half-circumference of the blower pipe 2, corresponding to the positions of the circumferential limiting grooves 20 and axial limiting grooves 30 provided in each half-circumference of the blower pipe 2.

[0064] The first protrusion 60 is inserted into the first end portion 20a of the circumferential limiting groove 20 when the front end portion of the base pipe 2A is inserted into the base end opening of the intermediate pipe 2B. In this embodiment, the first protrusion 60 is formed into a generally cubic shape.

[0065] like Figure 5 As shown, the axial length of the first protrusion 60 is formed to be significantly smaller than the axial length of the first end portion 20a of the circumferential limiting groove 20, so that when the first protrusion 60 is inserted into the circumferential limiting groove 20, the first protrusion 60 can move axially within the circumferential limiting groove 20.

[0066] In addition, the top of the first protrusion 60 is configured to engage with the recess of the concave-convex surface 21 of the circumferential limiting groove 20 in the circumferential direction.

[0067] If the top of the first protrusion 60 is engaged with the recess of the concave-convex surface 21, and the intermediate pipe 2B is rotated in the circumferential direction relative to the base pipe 2A, then the first protrusion 60 will pass over the convex part of the concave-convex surface 21, move to the adjacent recess, and engage.

[0068] The first protruding portion 60 can be engaged with any one of the recesses of the convexo-concave surface 21 of the circumferential restriction groove portion 20, and the abutting portion 50 provided at the front end portion of the base pipe 2A is in close contact with the inner circumferential surface of the intermediate pipe 2B. In the state where the first protruding portion 60 is engaged with the prescribed recess, the intermediate pipe 2B and the base pipe 2A are most stably connected. Thus, even if a dimensional error occurs in the outer diameter of the abutting portion 50 of the base pipe 2A and the inner diameter of the intermediate pipe 2B due to manufacturing, the first protruding portion 60 is engaged with the recess of any one of the convexo-concave surface 21 of the circumferential restriction groove portion 20 of the intermediate pipe 2B, and the intermediate pipe 2B and the base pipe 2A are stably connected.

[0069] The second protruding portion 70 is disposed at a position closer to the front end side (left side in FIG. 1) of the base pipe 2A than the first protruding portion 60. Figure 5 The second protruding portion 70 is a portion that is inserted into the insertion groove portion 40 when the front end portion of the base pipe 2A is inserted into the base end opening portion of the intermediate pipe 2B.

[0070] As shown in FIG. 1, the second protruding portion 70 of the present embodiment is formed as a polyhedron having a large width in the circumferential direction. Figure 3

[0071] As shown in FIG. 1, in the state where the second protruding portion 70 is inserted into the front end portion of the insertion groove portion 40, if the intermediate pipe 2B is rotated in the rotation direction A with respect to the base pipe 2A, the second protruding portion 70 enters the axial restriction groove portion 30 from the insertion groove portion 40. Figure 5

[0072] Further, if the intermediate pipe 2B is rotated in the rotation direction A with respect to the base pipe 2A while the base pipe 2A is inserted into the front end side of the intermediate pipe 2B, the side surface of the base end side of the second protruding portion 70 comes into abutment with the inclined edge portion 31 of the axial restriction groove portion 30.

[0073] Further, an angular portion is formed on the side surface of the base end side of the second protruding portion 70 in a manner to fit with the straight portion and the curved portion of the inclined portion based on the inclined edge portion 31.

[0074] Next, a procedure for connecting the intermediate pipe 2B and the base pipe 2A will be described.

[0075] As shown in FIG. 1, the base end portion of the intermediate pipe 2B is disposed on the front end side of the base pipe 2A, and the front end portion of the base pipe 2A is inserted into the base end opening portion of the intermediate pipe 2B. Figure 4 At this time, the position in the circumferential direction of the intermediate pipe 2B is aligned with respect to the base pipe 2A in a manner that the first protruding portion 60 is inserted into the circumferential restriction groove portion 20 and the second protruding portion 70 is inserted into the insertion groove portion 40.

[0076] ​​​

[0077] The first protrusion portion 60 is inserted into the circumferential restriction groove portion 20, and the top of the first protrusion portion 60 is engaged with the recess of the concave-convex surface 21. In addition, the second protrusion portion 70 is inserted into the insertion groove portion 40.

[0078] As shown in Figure 5 , the intermediate pipe 2B is inserted relative to the base pipe 2A to a position where the second protrusion portion 70 is inserted into the front end portion of the insertion groove portion 40, and the intermediate pipe 2B is rotated relative to the base pipe 2A in the rotational direction A. Thus, the second protrusion portion 70 enters the axial restriction groove portion 30.

[0079] In addition, if the base pipe 2A is inserted to the front end side of the intermediate pipe 2B while the intermediate pipe 2B is rotated relative to the base pipe 2A in the rotational direction A, as shown in Figure 2 , the abutting portion 50 of the base pipe 2A abuts against the reduced diameter portion 10 of the intermediate pipe 2B. In addition, the second protrusion portion 70 abuts against the inclined edge portion 31 of the axial restriction groove portion 30. Thus, the movement of the intermediate pipe 2B relative to the base pipe 2A in the axial direction is restricted.

[0080] In addition, the movement of the intermediate pipe 2B relative to the base pipe 2A in the circumferential direction is restricted by the engagement of the first protrusion portion 60 with the concave-convex surface 21 of the circumferential restriction groove portion 20.

[0081] In this way, by fixing the intermediate pipe 2B relative to the base pipe 2A in the axial and circumferential directions, the base pipe 2A and the intermediate pipe 2B are coupled.

[0082] As shown in Figure 5 , in the blower pipe 2 as described above, the movement of the base pipe 2A and the intermediate pipe 2B in the axial direction is restricted by the axial restriction groove portion 30 of the intermediate pipe 2B. The circumferential restriction groove portion 20 only needs to restrict the movement of the base pipe 2A and the intermediate pipe 2B in the circumferential direction, and thus the circumferential restriction groove portion 20 can be formed as a separate groove portion in the intermediate pipe 2B. As a result, the concave-convex surface 21 that is long in the axial direction is formed in the intermediate pipe 2B, and thus the dimensional error of the base pipe 2A and the intermediate pipe 2B in the axial direction can be addressed.

[0083] Thus, for the blower pipe 2 of the present embodiment, the coupling structure of the pipes 2A, 2B, 2C can be simplified Figure 1 , and the pipes 2A, 2B, 2C can be reliably coupled.

[0084] Thus, for the blower pipe 2 of the present embodiment, the structure of the mold for injection molding the pipes 2A, 2B, 2C can be simplified, and thus the manufacturing cost of the blower pipe 2 can be reduced by manufacturing the blower pipe 2 by injection molding.

[0085] In addition, as shown in Figure 3 the axial restriction groove portion 30 of the blower duct 2 of the present embodiment is an opening portion that penetrates the cylindrical portion, and thus, when the blower duct 2 is injection molded, the mold can be demolded to the outside in the radial direction with respect to the outer peripheral surface of the cylindrical portion, which simplifies the movement of the mold and enables the manufacturing cost to be reduced.

[0086] In addition, as shown in Figure 4 the axial restriction groove portion 30 of the blower duct 2 of the present embodiment is an opening portion that penetrates the cylindrical portion, and thus, when the blower duct 2 is injection molded, the mold can be demolded to the outside in the radial direction with respect to the outer peripheral surface of the cylindrical portion, which simplifies the movement of the mold and enables the manufacturing cost to be reduced.

[0087] In this structure, when the blower duct 2 is injection molded, the mold can be moved in the axial direction with respect to the intermediate duct 2B, and thus, the circumferential restriction groove portion 20 can be formed with a simple structure of the mold. Thus, the blower duct 2 can be easily injection molded.

[0088] As shown in Figure 3 the axial restriction groove portion 30 of the blower duct 2 of the present embodiment is an opening portion that penetrates the cylindrical portion, and thus, when the blower duct 2 is injection molded, the mold can be demolded to the outside in the radial direction with respect to the outer peripheral surface of the cylindrical portion, which simplifies the movement of the mold and enables the manufacturing cost to be reduced.

[0089] In this structure, the space of the intermediate duct 2B can be effectively used to arrange the circumferential restriction groove portion 20 and the axial restriction groove portion 30. Thus, it is easy to provide a plurality of circumferential restriction groove portions 20 and axial restriction groove portions 30 in the intermediate duct 2B.

[0090] Furthermore, in a case where the axial restriction groove portion 30 is arranged on the base end side in the axial direction with respect to the circumferential restriction groove portion 20, if the axial restriction groove portion 30 is arranged at the base end portion of the intermediate duct 2B, the base duct 2A is separated from the intermediate duct 2B, and thus, it is necessary to arrange the axial restriction groove portion 30 at a predetermined distance from the base end portion of the intermediate duct 2B. Thus, the arrangement becomes the order of the cylindrical portion, the axial restriction groove portion 30, and the circumferential restriction groove portion 20 from the base end side of the intermediate duct 2B toward the front end side, and thus, the connection structure becomes long in the axial direction.

[0091] In contrast, in a case where the axial restriction groove portion 30 is arranged on the front end side in the axial direction with respect to the circumferential restriction groove portion 20 as in the present embodiment, the connection structure can be formed to be small. In addition, by bringing the connection structure closer to the base end side of the intermediate duct 2B, it is possible to shorten the length of the base duct 2A and the intermediate duct 2B that overlap in the axial direction, and thus, it is possible to reduce the manufacturing cost and the weight of each of the base duct 2A and the intermediate duct 2B.

[0092] As shown in Figure 5 the inclined edge portion 31 of the axial restriction groove portion 30 of the intermediate duct 2B of the present embodiment is displaced in a stepped manner.

[0093] In this structure, the second protrusion 70 engages with the stepped portion of the inclined edge 31, making it difficult for the second protrusion 70 to be misaligned relative to the inclined edge 31 in the circumferential direction. Therefore, the intermediate pipe 2B is difficult to rotate relative to the base pipe 2A in the disengagement direction (opposite to the rotation direction A).

[0094] Furthermore, in the above-described embodiments, for Figure 1 The connection structure between the base pipe 2A and the intermediate pipe 2B is described, but the connection structure between the intermediate pipe 2B and the front pipe 2C is also the same structure and has the same effect.

[0095] The embodiments of this utility model have been described above, but this utility model is not limited to the above embodiments and can be appropriately modified within the scope without departing from its spirit.

[0096] like Figure 3 As shown, in this embodiment, the circumferential limiting groove 20 and the axial limiting groove 30 of the intermediate pipe 2B are arranged axially, but they can also be arranged circumferentially. In this case, the circumferential limiting groove 20 and the axial limiting groove 30 can be respectively provided in each half-circumference of the intermediate pipe 2B, or they can be divided into each 1 / 3 circumference, each 1 / 4 circumference, etc. of the intermediate pipe 2B, and multiple connecting parts can be provided in the circumference of the intermediate pipe 2B.

[0097] In addition, in this embodiment, the axial limiting groove 30 is disposed on the front end side of the intermediate pipe 2B relative to the circumferential limiting groove 20, but the circumferential limiting groove 20 may also be disposed on the front end side of the intermediate pipe 2B relative to the axial limiting groove 30.

[0098] In the blower duct 2 of this embodiment, the axial limiting groove 30 is an open portion, but the axial limiting groove 30 can also be formed by recessing the inner circumferential surface of the intermediate duct 2B.

[0099] In addition, in the blower duct 2 of this embodiment, the inclined edge 31 of the axial limiting groove 30 is formed in a stepped shape, but the inclined edge 31 can also be formed in a straight line or an arc shape.

[0100] Furthermore, in the blower duct 2 of this embodiment, an abutment portion 50 with multiple annular protrusions 51 is formed on the outer peripheral surface of the front end of the base duct 2A, but the shape of the abutment portion 50 is not limited. For example, at least one protrusion 51 may be formed. Alternatively, spiral or multiple protrusions may be configured to closely contact the inner peripheral surface of the intermediate duct 2B. In addition, the outer peripheral surface of the front end of the base duct 2A may be formed flat.

[0101] As Figure 6 shown, as another embodiment of the blower duct 2 of the present embodiment, a flexible portion 2E can be formed on the outer peripheral surface of the base duct 2A, and the first protrusion portion 60 can be arranged on the outer surface of the flexible portion 2E. The slits S are formed on both edge portions of the flexible portion 2E and the base end edge portion.

[0102] In this way, a part of the edge portion of the flexible portion 2E is cut off from the outer peripheral surface by the slits S, so that the flexible portion 2E can be bent toward the radial inner side with respect to the outer peripheral surface of the intermediate duct 2B.

[0103] In this structure, when the intermediate duct 2B is rotated in the circumferential direction with respect to the base duct 2A, and the first protrusion portion 60 passes over the convex portion of the convex-concave surface 21 of the circumferential restriction groove portion 20, the first protrusion portion 60 is pushed into the radial inner side of the intermediate duct 2B together with the flexible portion 2E. Thus, the intermediate duct 2B can be smoothly rotated in the circumferential direction with respect to the base duct 2A.

Claims

1. An air blower duct which is connected to an air discharge port formed by a power blower, characterized by comprising: a first duct; and a second duct connected to a front end portion of the first duct, wherein a circumferential restriction groove portion and an axial restriction groove portion are formed in the second duct, wherein a first protrusion portion is formed on an outer peripheral surface of the first duct so as to be inserted into the circumferential restriction groove portion, and a second protrusion portion is formed on the outer peripheral surface of the first duct so as to be inserted into the axial restriction groove portion, wherein a base end opening portion of the second duct is formed so as to be inserted into the front end portion of the first duct, and wherein the first duct and the second duct are connected in a state in which the first protrusion portion is engaged to the circumferential restriction groove portion in a circumferential direction of the second duct and the second protrusion portion is engaged to the axial restriction groove portion in an axial direction of the second duct.

2. The air blower duct according to claim 1, characterized in that the circumferential restriction groove portion and the axial restriction groove portion extend in the circumferential direction of the second duct, in that the circumferential restriction groove portion is recessed to an outer side in a radial direction of the second duct with respect to an inner peripheral surface of the second duct, and a concave-convex surface in which concave-convex portions are continuously formed in the circumferential direction of the second duct is formed on an inner surface of the circumferential restriction groove portion, in that an inclined edge portion is formed in a rim portion on a base end side of the second duct in the axial restriction groove portion, the inclined edge portion being displaced to a front end side of the second duct as it approaches from one side to the other side in the circumferential direction of the second duct, in that the base end opening portion of the second duct is formed so as to be inserted into the front end portion of the first duct, in that the second protrusion portion abuts against the inclined edge portion of the axial restriction groove portion, and in that the first duct and the second duct are connected in a state in which the first protrusion portion is engaged to the concave-convex surface of the circumferential restriction groove portion.

3. The air blower duct according to claim 1, characterized in that the circumferential restriction groove portion and the axial restriction groove portion are arranged in the axial direction of the second duct.

4. The air blower duct according to claim 1, characterized in that the circumferential restriction groove portion is arranged at a base end portion of the second duct, and in that a portion on the base end side of the second duct is opened in the circumferential restriction groove portion.

5. The air blower duct according to claim 1, characterized in that the axial restriction groove portion is an opening portion which penetrates a cylindrical portion of the second duct.

6. The air blower duct according to claim 2, characterized in that the inclined edge portion is displaced to the front end side of the second duct in a stepped manner as it approaches from one side to the other side in the circumferential direction of the second duct.

7. The air blower duct according to claim 1, characterized in that the first protrusion portion is arranged on an outer surface of a flexible portion formed on an outer peripheral surface of the second duct, and in that the flexible portion has flexibility in the radial direction of the second duct.

8. The air blower duct according to claim 1, characterized in that a reduced diameter portion which reduces the inner peripheral surface of the second duct in a diameter is formed in the second duct, in that the base end opening portion of the second duct is formed so as to be inserted into the front end portion of the first duct, and in that the first protrusion portion is engaged to the concave-convex surface of the circumferential restriction groove portion in a state in which the second protrusion portion is engaged to the inclined edge portion of the axial restriction groove portion. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The first pipe is connected to the second pipe in a state in which the front end portion of the first pipe abuts against the reduced diameter portion of the second pipe.

9. The blower duct of claim 8, wherein At least one protrusion is provided on the outer peripheral surface of the front end portion of the first pipe, the protrusion abutting against the peripheral surface of the reduced diameter portion of the second pipe.

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