JP2001289026A - Air duct with sound absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight air duct with a sound absorbing material having the simple structure and easily installable in the air duct. SOLUTION: In this air duct with the sound absorbing material with the structure that the sound absorbing material is inserted into an enlarged diameter part 30 provided over the predetermined length at a part close to a central part in the axial direction of the air duct 21, the air duct 21 is divided into plural members at least at the enlarged diameter part 30. This division can be performed in a plane surface including the axis, or in a plane surface at a right angle against the axis. The sound absorbing material 40 and 40a desirably have the inner diameter larger than the inner diameter of the air duct 21 at both ends thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind tube having a sound absorbing material provided with a sound absorbing material in a wind tube through which air or the like flows.

[0002]

2. Description of the Related Art Conventionally, air of a blower flowing in a cylindrical tube,
Alternatively, various arrangements in which a muffler is provided in the middle of a pipe in order to reduce noise such as engine exhaust are found. As an example, Japanese Patent No. 2967390 (U.S. Pat.
Pat. No. 5718045), JP-A-10-19000
No. 5,827,473, U.S. Pat. No. 5,821,473.
S. There is one disclosed in Pat. No. 4421202.

The first example disclosed in Japanese Patent No. 2967390 aims to reduce the exhaust noise of an internal combustion engine. As shown in FIG. 9, the silencer 50 is configured by interposing a sound absorbing material 53 such as glass wool in an annular gap formed between an inner perforated tube 51 and an outer tube 52 surrounding the perforated inner tube 51. I have. Front and rear end portions 51a, 51b of the porous inner tube 51
Has a larger diameter than the middle part. The outer circumferences of the caps 55 and 56 are welded to the front and rear ends of the outer tube 52, respectively. A plurality of separator plates 54 are provided inside the perforated inner tube 51.
a, 54b, 54c, and a plurality of exhaust expansion chambers C1,
C2, C3, and C4 are formed. At the time of assembling, a sound absorbing material 53 having a predetermined thickness coated with a binder is wound around the outer periphery of the porous inner tube 51 to which the separator plates 54a, 54b, 54c are attached, and roll forming is performed using an ironing roller (not shown). It is designed to be inserted into the outer tube 52.

A second example of Japanese Patent Application Laid-Open No. Hei 10-19000 discloses a silencer mounted on a blower pipe (corresponding to a wind tube according to the present invention) of a portable blower.
As shown in FIG. 10, the muffler 60 includes a blower pipe 6.
1 is an enlarged diameter portion 6 extending in the axial direction over a predetermined length L1.
2, an inner pipe 63 having a large number of sound deadening holes 64 is inserted into the enlarged diameter portion 62, and an annular gap formed between the inserted inner pipe 63 and the enlarged diameter portion 62 is made of urethane foam. The sound absorbing member 65 is interposed. The inner pipe 63 is composed of a pair of thin plate materials divided into two in the axial direction, and when assembling, a sound deadening material 65 is attached to each outer periphery, and the pair of thin plate materials are bent so that the end of the blower pipe 61 is bent. Insert the enlarged diameter part 6
2 for storage. As another method, as shown in FIG. 11, the inner pipe 63 is formed by a strip 66 formed into a spiral shape made of a flexible material having appropriate elasticity such as polypropylene. . The band 66 is provided with a large number of sound deadening holes 64. At the time of mounting, first, the silencer 65 is inserted from one end of the blower pipe 61, and the silencer 65 is placed in the enlarged diameter portion 62. Next, the strip 66 is pulled in the axial direction to have its outer diameter d2.
Is made smaller than the inner diameter d1 of the blower pipe 61 and inserted into the blower pipe 61.
6, the outer diameter d2 is increased, and the muffling material 65 is pressed and attached to the enlarged diameter portion 62.

The U.S. Pat. S. Pat.No. 4421
As shown in the perspective view of FIG. 12, a noise reduction device 70 disclosed in No. 202 has a pair of collars 72,
An inner tube 73 provided with the inner tube 72 is inserted, and a sound absorbing material 74 is interposed in an annular gap formed between the outer tube 71 and the inner tube 73. The pair of collars 72 are fastened to the outer cylinder 70 by screws 75. Inner cylinder 73
Is a braided braid made of resin and solidified with resin, and has many voids.

[0006]

However, the above configuration has the following problems. 1) The one disclosed in Japanese Patent No. 2967390 has a problem that the number of components is large, the size is large, the structure is complicated, the weight is heavy, and the cost is high. 2) In the device disclosed in Japanese Patent Application Laid-Open No. 10-19000, the operation of housing the sound deadening material 65 in the enlarged diameter portion 62 is very troublesome, and the inner pipe 63 is placed inside the sound deadening material 65. Need to be inserted. Therefore, there is a problem that assembly is complicated, man-hours are required, the number of parts is large, and the cost is high. 3) See also U.S.A. S. The system disclosed in Pat. No. 4421202 has a problem that the number of parts is large, the structure is complicated, a large number of steps are required for assembly, and the cost is high.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a wind tube with a sound absorbing material that can be easily mounted on a wind tube, is lightweight, has a simple structure, and has a small number of parts.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention relates to a method of manufacturing a wind pipe having a large diameter provided at a position near a center in an axial direction of a ventilating pipe. In a wind tube with a sound absorbing material fitted with a sound absorbing material, the wind tube is divided into a plurality of members at least at the enlarged diameter portion. According to the above configuration, since the wind pipe is divided into a plurality of members at least at the enlarged diameter portion, it is extremely easy to mount the sound absorbing material inside the enlarged diameter portion from the opening side of the enlarged diameter portion in the divided state. In addition, since the inner tube is unnecessary and the weight is reduced, the manufacturing cost can be reduced. In addition, since the sound absorbing material can be reliably and accurately attached to the enlarged diameter portion, good sound absorbing quality can be obtained.

In the present invention, the division may be a division on a plane including an axis. According to this configuration, the sound absorbing material can be easily and reliably mounted inside the enlarged diameter portion, and the members can be easily manufactured and the cost can be reduced.

In the present invention, the division may be a division on a plane perpendicular to the axis. According to this configuration, the sound absorbing material can be easily and reliably mounted inside the enlarged diameter portion, and the members can be easily manufactured and the cost can be reduced. In addition, it is easy to ensure the accuracy of the shape of both ends of the wind tube connected to the enlarged diameter portion, and it is possible to obtain a wind tube having excellent appearance quality and sound absorbing effect.

Further, it is preferable that the sound absorbing material has an inner diameter larger than the inner diameter of both ends of the wind tube. According to this, the flow of the wind flowing in the air duct becomes smooth, dust and the like do not accumulate in the enlarged diameter portion, and good performance can be maintained.

Further, in these configurations, it is preferable that the air tube is configured to be assembled and disassembled by the plurality of members. According to this configuration, since the air tube including the enlarged diameter portion is configured to be assembled and disassembled, the sound absorbing material provided inside the enlarged diameter portion can be replaced, and therefore, a good sound absorbing effect can be maintained for a long time. it can.

[0013] In the above structure, the plurality of members constituting the air duct may be fixed to each other. According to this configuration, the structure is simple, mounting holes such as joining bolts and nuts are unnecessary, the number of parts is small,
Cost can be reduced.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. A portable blower will be described as an example of a machine to which the present invention is applied.

First, referring to FIG. 1, a schematic configuration of a portable blower 1 having a wind tube with a sound absorbing material according to the present invention will be described. About L
A blower 4 driven by an engine 5 is mounted on the frame 3 of the mold. An elbow 10 is attached to the air discharge port 7 of the blower 4, and an upstream wind pipe 12, a wind pipe 20 with a sound absorbing material, and a downstream wind pipe 13 are sequentially provided at the tip of the elbow 10 via a flexible tube 11. Is connected. The operator carries the portable blower 1 and performs the cleaning operation while holding the air tubes 12 and 13.

FIG. 2 is a side sectional view of the air tube 20 with sound absorbing material of the first embodiment, and FIG. 3 is an exploded perspective view thereof. FIG.
As shown in FIG. 3, a large-diameter portion 30 having a predetermined length L is provided at a substantially central portion in the longitudinal direction of the resin air tube 21. The sound absorbing material 40 is fitted into the enlarged diameter portion 30, and the magnitude relationship between the inner diameter D 2 of the sound absorbing material 40 and the inner diameters D 1 at both ends of the wind tube 21 is “D 2 ≧ D 1”. An upstream wind tube portion 24 is provided upstream of the enlarged diameter portion 30, and a downstream wind tube portion 2 is provided downstream thereof.
5 are formed. The upstream wind pipe 12 is fitted inside the upstream wind pipe section 24, and the downstream wind pipe 13 is fitted outside the downstream wind pipe section 25. As shown in FIG. 3, the air tube 21 having the enlarged diameter portion 30 has a configuration in which the air tube 21 is divided into a one-side air tube 22 and a second-side air tube 23 by a plane including an axis. 22 and the other-side air tube 23 are provided with a one-side enlarged diameter portion 31 and another-side enlarged diameter portion 32, respectively. Inside the one-side enlarged diameter portion 31 and the other-side enlarged diameter portion 32, a sound absorbing material 4 having a shape obtained by dividing a cylinder into two parts by a plane including an axis is provided.
0, the one-side sound absorbing material 41 and the other-side sound absorbing material 42 are fitted respectively. Sound absorbing material 40 is open cell (porous)
(For example, urethane foam).

When assembling, the one-side sound absorbing material 41 and the other-side sound absorbing material 42 are provided inside the one-side enlarged diameter portion 31 of the one-side wind tube 22 and the other-side enlarged diameter portion 32 of the other side wind tube 23, respectively. Together, the upstream wind pipe section 24 and the downstream wind pipe section 2 are provided at both ends.
5 is formed. The upstream wind tube 24 is fastened and fixed from outside by a band 26, and the upstream wind tube 12 is inserted into the inside of the upstream wind tube 24. The downstream air tube 13 is inserted into the downstream air tube portion 25 from the outside, and the one air tube 22 and the other air tube 23 are fixed. At this time, the end surfaces 41a and 42a of the one-side sound absorbing material 41 and the other-side sound absorbing material 42 provided therein come into contact with each other and are compressed, and the outer diameter portions thereof are the one-side enlarged diameter portion 31 and the other-side enlarged diameter portion 32, respectively. Is pressed into contact with the inner diameter portion.

With the above configuration, the noise of the air discharged from the blower 4 is absorbed by the sound absorbing material 40 and reduced. Further, the structure is simple, the number of parts is small, and the weight is low. Then, since the sound absorbing material 40 is mounted through the opening of the large diameter portion 30 with the inside of the large diameter portion 30 open, the sound absorbing material 4
0 can be mounted very easily and reliably, disassembly and assembly are easy, and the cost can be reduced. Further, since the disassembling and assembling are easy, the sound absorbing material 40 can be easily replaced, and good sound absorbing performance can be maintained for a long time. Further, the inner diameter D of the sound absorbing material 40
2 is equal to or larger than the inner diameter D1 at both ends of the air tube 21, so that an excellent air tube with a sound-absorbing material having less resistance to wind flow and less accumulation of dust and the like can be obtained. Furthermore, the enlarged diameter portion 3 is formed by the reaction force against the compression of the sound absorbing material 40.
0 is pressed outward from inside and band 2 is applied from outside.
6 and the downstream air tube 13, so that the shape of the sound absorbing material-added air tube 20 can be maintained and firmly fixed even in a divided configuration.

In the first embodiment, the one-side air tube 22 and the other-side air tube 23, which are divided into two, are fastened and fixed by the band 26 and the downstream air tube 13. As another example, although not shown, the one-side air duct 2
2 and the other-side air tube 23 may be bonded with an adhesive or the like. This eliminates the need for the band 26 and bolts,
Further, the number of parts can be reduced, and the cost can be reduced.

The second embodiment will be described with reference to FIGS. FIG. 4 is a side sectional view of a wind tube 20a with a sound absorbing material of the second embodiment, and FIG. 5 is an exploded perspective view thereof. As shown in FIG. 4, an enlarged diameter portion 30 having a predetermined length L is provided substantially at the center of the wind tube 21 in the longitudinal direction. The inner diameter D2 of the sound absorbing material 40a is the inner diameter D of the upstream wind pipe 22a and the downstream wind pipe 23a.
It is set equal to or greater than 1. 4 and 5, the enlarged diameter portion 30 is divided into an upstream enlarged diameter portion 31a and a downstream enlarged diameter portion 32a at a plane perpendicular to the axis. , 34 are provided. Fastening flange 33,
A predetermined number of screw holes 35 are formed in 34. A cylindrical sound absorbing material 40a made of urethane foam is fitted into the upstream-side enlarged diameter portion 31a and the downstream-side enlarged diameter portion 32a.

The assembling is performed by installing the sound absorbing material 4 in the upstream enlarged diameter portion 31a.
0a, and the other end of the sound absorbing material 40a is inserted into the downstream enlarged diameter portion 32a.
34, and is fastened with a screw 36 and a nut 37.

As for the operation and effects, as in the first embodiment, the structure is simple, the number of parts is small, the weight is small, the mounting of the sound absorbing material 40a is very easy and reliable, and the disassembly and assembly are easy. In addition, the cost can be reduced. Further, since the both ends of the enlarged diameter portion 30 and the both ends of the wind tube are divided so as to be joined, it is easy to secure the shape accuracy of the both ends of the wind tube, so that a wind tube with good appearance quality and sound absorbing effect can be obtained. .

FIG. 6 is a cross-sectional side view of a sound-absorbing air tube 20b showing another joining method of the upstream enlarged diameter portion 31a and the downstream enlarged diameter portion 32a in the second embodiment. The same components as those of the second embodiment are denoted by the same reference numerals, description thereof will be omitted, and only different portions will be described. Upstream expanding part 3
Adhesion flanges 33a and 34a are provided on the open end surfaces of 1a and the downstream enlarged diameter portion 32a, respectively. When assembling, the bonding flange 33a of the upstream-side enlarged-diameter portion 31a is used.
And the flange 34a for adhesion of the downstream enlarged diameter portion 32a are brought into contact with each other and joined with an adhesive or the like. The operation and effects are the same as those of the second embodiment, the structure is simple, mounting holes such as bolts and nuts for joining are unnecessary, the number of parts is small, and the cost can be reduced.

FIG. 7 shows a wind tube 20c with a sound absorbing material according to the third embodiment.
FIG. Enlarged portion 3 at almost the center in the longitudinal direction
0 is formed by dividing both ends of the enlarged-diameter portion 30 by a plane perpendicular to the axis, and the upstream-side air tube 22b and the enlarged-diameter tube 3
0a and a downstream air tube 23b. Opposite ends of the upstream wind pipe 22b and the downstream wind pipe 23b have lids 22c, 23c, respectively, and the lids 22c, 23c are provided with fastening lid flanges 33b, 34b, respectively. Further, fastening flanges 3 facing the fastening lid flanges 33b and 34b are provided at both ends of the enlarged diameter cylinder 30a.
3, 34 are provided. A predetermined number of screw holes 3 are provided in each of the flanges 33, 33b, 34, 34b.
5 are provided. A sound absorbing material 40a is fitted in the enlarged diameter portion 30.

At the time of assembling, first, the sound absorbing material 40a is inserted into the enlarged-diameter cylinder 30a, and then the lid 22c of the upstream wind pipe 22b and the lid of the downstream air pipe 23b are placed from both sides of the enlarged cylinder 30a. 2
3c, the fastening flanges 33, 34 and the fastening lid flanges 33b, 34b are brought into contact with each other and fastened with the screw 36 and the nut 37. The operation and effect are the same as those of the second embodiment, and therefore the description is omitted.

In the third embodiment, the method of joining the flanges on both sides of the diameter-enlarging cylinder 30a to the lid 22c of the upstream wind pipe 22b and the lid 23c of the downstream wind pipe 23b is not limited to fastening. For example, as shown in FIG. 8, each of the bonding lid flanges 3 of the upstream wind pipe 22b and the downstream wind pipe 23b.
3c, 34c and the bonding flanges 33a, 34a at both ends of the enlarged diameter tube 30a may be brought into contact with each other and bonded with an adhesive or the like. The operation and effect are the same as those of the second embodiment, and therefore the description is omitted.

As described above, according to the present invention, since the air tube is constituted by a plurality of members divided at least by the enlarged diameter portion, the sound absorbing material can be easily inserted into the enlarged diameter portion from the opening of the enlarged diameter portion. And it can be attached securely. Therefore, with a simple structure,
In addition, the mounting of the sound absorbing material and the assembly of the wind tube with the sound absorbing material can be facilitated, the manufacturing cost can be reduced, and good sound absorbing quality can be obtained. Since the above-mentioned division is made on a plane including the axis, or on a plane perpendicular to the axis, the sound absorbing material can be easily and securely mounted in the enlarged diameter portion, and the members can be easily manufactured and the cost is reduced. Can be cheaper. In addition, since the plurality of divided members are configured to be assembled and disassembled, the sound absorbing material can be replaced, and a good sound absorbing effect can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a perspective view of a portable blower provided with an air tube with a sound absorbing material of the present invention.

FIG. 2 is a side sectional view of the air tube with a sound absorbing material of the first embodiment.

FIG. 3 is an exploded perspective view of the air tube with a sound absorbing material of the first embodiment.

FIG. 4 is a side sectional view of a wind tube with a sound absorbing material according to a second embodiment.

FIG. 5 is an exploded perspective view of a wind tube with a sound absorbing material according to a second embodiment.

FIG. 6 is a side sectional view of an air tube with a sound absorbing material showing another joining method according to the second embodiment.

FIG. 7 is a side sectional view of a wind tube with a sound absorbing material according to a third embodiment.

FIG. 8 is a side sectional view of an air tube with a sound absorbing material showing another joining method according to the third embodiment.

FIG. 9 is a side sectional view of a silencer with a sound absorbing material according to a first example of the prior art.

FIG. 10 is a side sectional view of a wind tube with a sound absorbing material according to a second example of the prior art.

FIG. 11 is a side view of an inner pipe of a wind tube with a sound absorbing material according to a second example of the related art.

FIG. 12 is an exploded perspective view of a wind tube with a sound absorbing material of a third example of the prior art.

[Explanation of symbols]

1: Portable blower, 4: Blower, 11: Flexible tube, 12: Upstream air tube, 13: Downstream air tube, 20, 20
a, 20b, 20c, 20d: wind tube with sound absorbing material, 21: wind tube, 22: one-side wind tube, 22a, 22b: upstream-side wind tube, 2
3: other side wind pipe, 23a, 23b: downstream wind pipe, 22c,
23c: lid portion, 24: upstream wind tube portion, 25: downstream wind tube portion, 26: band, 30: expanded portion, 30a: expanded tube, 3
1: One-side enlarged diameter part, 31a: Upstream enlarged diameter part, 32: Other-side enlarged diameter part, 32a: Downstream enlarged diameter part, 33, 34: Fastening flange, 33a, 34a: Adhesive flange, 33b, 34
b: fastening lid flange, 33c, 34c: bonding lid flange, 35: screw hole, 36: screw, 37: nut,
40, 40a: sound absorbing material, 41: one side sound absorbing material, 42: other side sound absorbing material, 41a, 42a: end face.

Claims (6)

[Claims] 1. A wind tube with a sound absorbing material in which a sound absorbing material is inserted into an enlarged diameter portion provided over a predetermined length at a position near a central portion in the axial direction of a ventilating wind tube, wherein the wind tube (21) has at least An air tube with a sound absorbing material, wherein the air tube is divided into a plurality of members at the enlarged diameter portion (30). 2. The air tube with a sound absorbing material according to claim 1, wherein the division is a division on a plane including an axis. 3. The air tube with a sound absorbing material according to claim 1, wherein the division is a division on a plane perpendicular to an axis. 4. The air tube with a sound absorbing material according to claim 1, 2 or 3, wherein the sound absorbing material (40, 40a) has an inner diameter larger than the inner diameter of both ends of the air tube (21). An air tube with sound absorbing material. 5. The air tube with a sound absorbing material according to claim 1, 2 or 3, wherein said air tube (21) is configured to be assembled and disassembled by said plurality of members. Wind tube. 6. The sound-absorbing air tube according to claim 1, wherein the plurality of members constituting the air tube are fixed to each other. Wind tube with lumber.