JP2008240693A - Intake duct with muffler and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake duct with a muffler of a simple joining structure not requiring a complicated assembly process and not leaking noise from a vicinity of the muffler. <P>SOLUTION: The intake duct with the muffler comprises a duct main body 1 having a muffler part 13 connected between a second end part 12 and a first end part 11 as a general part of the intake duct, and an inner duct 2 arranged inside of a large diameter pipe part 13c of the muffler part 13. The inner duct 2 is arranged inside of the large diameter pipe part 13c of the muffler part 13 to form a muffler chamber 3 between the inner duct 2 and the large diameter pipe part 13c, and a connection part 5 establishing communication between the muffler chamber 3 and a duct inside 4. Since no welding joining part exists on a wall part dividing the muffler chamber 3, there is no concern about leak of noise. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air intake duct with a silencer and a method of manufacturing the same, and more particularly, to an air intake duct connected to an internal combustion engine such as a vehicle, and for silencing noise generated or propagated in an air flow path in the air intake duct The present invention relates to a silencer-equipped intake duct and a method of manufacturing the same.

  2. Description of the Related Art As an intake duct connected to an internal combustion engine such as an automobile, there is known an intake duct having a silencer for eliminating noise generated or propagated in an air flow path in the intake duct.

  As such an air intake duct with a silencer, for example, as shown in FIG. 6, a first end 71 and a second end 72 as general portions at both ends, and a first silencer having a larger diameter than these general portions. There is one in which a first intermediate part 73 and a second intermediate part 74 having an instrument part 73a and a second silencer part 74a are integrally formed.

  In this air intake duct with a silencer, the first end 71 and the second end 72, which are fastening parts with an air cleaner and a throttle body, are made of soft resin (CR, TPO, etc.) in order to ensure assembly and airtightness. Become. On the other hand, since the first silencer portion 73a and the second silencer portion 74a need to suppress radiated sound from the wall surface, the first intermediate portion 73 and the second intermediate portion 74 are made of hard resin (PP, PA, etc.). It becomes more. And these four parts of the 1st end part 71, the 2nd end part 72, the 1st intermediate part 73, and the 2nd intermediate part 74 are joined integrally by welding, respectively.

  Further, as shown in FIG. 7, the first end portion 81 and the second end portion 82 as general portions made of synthetic rubber, and the first silencer portion 83a and the second silencer portion 84a made of hard resin are provided. Some include a first intermediate portion 83 and a second intermediate portion 84. In the intake duct with the sound absorber, the first intermediate portion 83 and the second intermediate portion 84 are integrally joined by welding, and the first end portion 81 and the first intermediate portion 83 are fastened by the first clamp 85. The second end portion 82 and the second intermediate portion 84 are fastened by the second clamp 86.

Further, as shown in FIG. 8, there are some composed of a first end portion 91 and a second end portion 92 as general portions, and an inner portion 94 and an outer portion 95 for forming a sound deadening chamber 93 (for example, , See Patent Document 1). In the intake duct with the sound absorber, the coupling portion 95a of the outer portion 95 is tightly bound to the outer peripheral surface of the inner portion 94, and the first end portion 91, the second end portion 92, and both end portions of the inner portion 94 are connected to each other. Are fastened by a first clamp 96 and a second clamp 97.
Japanese Patent No. 3487031

  However, in the conventional air intake duct with a silencer shown in FIGS. 6 and 7, since there are two welded joints on the wall part that defines the silencer chamber, the sound from the welded joints is present. In order to reliably prevent leakage, strict management is required to ensure sealing performance at the welded joint.

  Further, in the conventional air intake duct with a silencer shown in FIG. 8, since the coupling portion 95a of the outer portion 95 is only tightly bound to the outer peripheral surface of the inner portion 94, sound leakage occurs from the coupling portion 95a. I will. In order to prevent sound leakage from the coupling portion 95a, for example, a complicated shape must be applied to the coupling portion 95a to ensure the bonding strength and the sealing performance.

  The present invention has been made in view of the above circumstances, and it is intended to provide an intake duct with a silencer that has a simple coupling structure, does not require a complicated assembly process, and has a low risk of sound leakage from the vicinity of the silencer. Objective.

  The air intake duct with a silencer of the present invention that solves the above problems is a pair of small-diameter cylindrical parts connected to the general part of the air-intake duct, respectively, and an axially inner end of each small-diameter cylindrical part. A pair of medium-diameter cylindrical portions having a larger diameter than the small-diameter cylindrical portion, and an axial outer end connected to the axial inner end of each medium-diameter cylindrical portion. A silencer portion having a large diameter cylindrical portion larger than the cylindrical portion, and at least one of both axial end portions is held by the medium diameter cylindrical portion, and a silencer chamber is provided between the large diameter cylindrical portion. And an inner duct that forms a communication portion that communicates between the sound deadening chamber and the inside of the duct.

  In the intake duct with a silencer, a small diameter cylindrical portion of the silencer portion is connected to a general portion of the intake duct. And the inner duct is hold | maintained at the intermediate diameter cylinder part of this silencer part. That is, a silencer chamber is formed between the large-diameter cylindrical portion of the silencer part and the inner duct by arranging the inner duct inside the silencer part. For this reason, there is no welded joint in the wall that partitions the sound deadening chamber. Therefore, strict gap management for preventing sound leakage is unnecessary, and there is no concern about sound leakage from the welded joint. Therefore, it is not necessary to make the coupling structure complicated as a sound leakage prevention measure, and a complicated assembling process is unnecessary.

  In the intake duct with a silencer of the present invention, both axial end portions of the inner duct are held by the medium-diameter cylindrical portions, and the communication portion is formed by a slit portion formed in advance in the inner duct. preferable.

  If both of the both axial end portions of the inner duct are held by both middle diameter cylindrical portions, the inner duct can be more reliably held with respect to the silencer portion. Further, by forming the slit portion in the inner duct in advance, it is possible to easily form a communication portion that communicates the sound deadening chamber with the inside of the duct.

  Further, when both the axial end portions of the inner duct are held by the medium diameter cylindrical portions, both axial end surfaces of the inner duct are in contact with the axial inner end surfaces of the small diameter cylindrical portions. It is preferable. If both axial end faces of the inner duct are in contact with the axial inner end faces of both small-diameter cylindrical portions, the inner duct can be reliably held while being restricted in the axial direction with respect to the silencer portion.

  In the intake duct with a silencer of the present invention, one end portion in the axial direction of the inner duct is held by one of the medium-diameter cylindrical portions, and the communication portion is connected to an outer end in the axial direction at the other end portion in the axial direction of the inner duct. It is preferable that the gap portion is formed between the other inner diameter cylindrical portion and the inner end in the axial direction.

  As long as the communicating portion is formed by the gap between the outer end in the axial direction of the inner duct and the inner end in the axial direction of the medium-diameter cylindrical portion, it is predetermined with respect to the middle-diameter cylindrical portion of the silencer portion. By holding one end of the inner duct in the axial direction in the axial direction, a communication portion having a predetermined size can be easily formed.

  In the intake duct with a silencer of the present invention, it is preferable that an inner diameter of the inner duct and an inner diameter of the small-diameter cylindrical portion are substantially the same.

  If the inner diameter of the inner duct and the inner diameter of the small diameter cylindrical portion of the silencer portion are substantially the same, the air flow through the air flow path in the duct becomes smooth. For this reason, it becomes advantageous for suppressing the pressure loss resulting from the turbulent flow generated in the air flow path in the intake duct.

  In the intake duct with a silencer according to the present invention, it is preferable that the inner duct has a reinforcing wall portion that protrudes integrally from the outer surface of the inner duct in the centrifugal direction and contacts the inner surface of the large-diameter cylindrical portion.

  When the silencer part is formed by, for example, three-dimensional blow molding, the large-diameter cylindrical part in the silencer part tends to be thin. When the wall of the large-diameter cylindrical portion becomes thin, noise may be generated due to pulsation of the thin wall portion having low rigidity. In this regard, if there is a reinforcing wall portion that comes into contact with the inner surface of the large-diameter cylindrical portion, the rigidity of the large-diameter cylindrical portion increases, so that generation of noise due to pulsation can be suppressed.

  In the intake duct with a silencer of the present invention, it is preferable that the general part is made of a soft resin, and the silencer part is made of a hard resin harder than the soft resin.

  If the general part is made of a soft resin, it is easy to ensure assemblability and airtightness at the fastening site with the air cleaner and the throttle body. Moreover, if a silencer part consists of hard resin, the emitted sound from the wall surface of a silencer part can be suppressed more reliably.

  In the intake duct with a silencer of the present invention, it is preferable that the general portion and the silencer portion are provided with a duct body formed integrally by three-dimensional blow molding.

  By performing three-dimensional blow molding of the duct body, the general part of the intake duct and the silencer part can be easily integrally formed. Moreover, it becomes easy to make a material different in a general part and a silencer part.

  A method of manufacturing an air intake duct with a silencer according to the present invention that solves the above-described problems includes a general portion of an air intake duct, a large diameter cylindrical portion that is integrally formed with the general portion by three-dimensional blow molding, and has a larger diameter than the general portion. A silencer having a duct body, and a silencer chamber formed between the duct body and the large-diameter cylindrical portion disposed inside the large-diameter cylindrical portion, and communicating the silencer chamber with the duct interior An air intake duct with a silencer, comprising: an inner duct that forms a communicating portion, wherein the inner duct is disposed in a mold for three-dimensional blow molding, and between the inner duct and the mold An arrangement step of inserting and arranging a parison for forming the duct body, a mold clamping step of clamping the mold, and blowing the air into the parison to three-dimensionally blow the duct body, and the silencer section The inner duct And it is characterized in that it comprises a and a blowing step of.

  In the arrangement step in the method of manufacturing the intake duct with a silencer, an inner duct having a predetermined shape prepared in advance is arranged in a mold for three-dimensional blow molding. At this time, it is preferable to hold the inner duct with a mandrel or the like. Moreover, in this arrangement | positioning process, the parison for duct main body shaping | molding is inserted and arrange | positioned between an inner duct and a type | mold. Then, after the mold is clamped in the mold clamping process, the blow process is performed. In this blowing process, air is blown into the parison to form a three-dimensional blow molding of the duct body, and the silencer portion holds the inner duct. Thereby, the duct main body by which the silencer part and the general part were integrally molded can be formed by three-dimensional blow molding. In addition, an inner duct is disposed inside the silencer unit and is integrally held, and a silencer chamber is formed between the inner duct and the large-diameter portion of the silencer unit. An air intake duct with a silencer in which a communicating part is formed can be obtained.

  Therefore, according to the method of manufacturing an intake duct with a silencer of the present invention, an intake duct with a silencer in which an inner duct is disposed inside a duct body in which a general part of the intake duct and a silencer part are integrally formed is provided. Can be easily obtained. In this air intake duct with a silencer, there is no welded joint in the wall section that defines the sound deadening chamber, so there is no need for strict gap management to prevent sound leakage, and there is no fear of sound leakage from the welded joint. Therefore, it is not necessary to make the coupling structure complicated as a sound leakage prevention measure, and a complicated assembling process is unnecessary.

  Therefore, according to the present invention, it is possible to provide a silencer-equipped intake duct that has a simple coupling structure, does not require a complicated assembly process, and is less likely to leak sound from the vicinity of the silencer.

  Hereinafter, the embodiment about the air intake duct with a silencer of the present invention is described concretely.

(Embodiment 1)
The intake duct with a silencer of this embodiment shown in FIG. 1 is composed of two parts, a duct body 1 and an inner duct 2 that is integrally disposed inside the duct body 1.

  The duct body 1 includes a first end portion 11 and a second end portion 12 as general portions of the intake duct, and a silencer portion 13 having a diameter larger than those of the first end portion 11 and the second end portion 12. ing. And the 1st end part 11 and the 2nd end part 12 as a general part consist of soft resins, and the silencer part 13 consists of hard resin harder than this soft resin.

  Here, the material of the soft resin and the hard resin is not particularly limited. For example, TPO (thermoplastic polyolefin) or TEEE (polyester elastomer) can be used as the soft resin. Further, as the hard resin, for example, PP (polypropylene) or PBT (polybutylene terephthalate) can be employed.

  The duct body 1 is formed by integrally forming a first end portion 11 and a second end portion 12 as a general portion and a silencer portion 13 by multilayer three-dimensional blow molding.

  The first end portion 11 has a first fastening end portion 11a fastened to the air cleaner. The second end portion 12 has a second fastening end portion 12a fastened to the throttle body and a vibration-absorbing bellows portion 12b.

  The silencer unit 13 includes a pair of small-diameter tube portions 13a and 13a at both ends in the axial direction, a pair of medium-diameter tube portions 13b and 13b at the axially inner sides of the small-diameter tube portions 13a and 13a, and both medium-diameter tubes. And a large-diameter cylindrical portion 13c between the portions 13b and 13b.

  One end face of the small-diameter cylindrical portion 13a (left side in FIG. 1) and the inner end in the axial direction of the first end portion 11 on the left side in FIG. Similarly, the end surfaces of the other (the right side in FIG. 1) small-diameter cylindrical portion 13a and the inner end in the axial direction of the second end portion 12 on the right side in FIG. . The inner diameters of the small-diameter cylindrical portions 13a and 13a are equal to the inner diameters of the first end portion 11 and the second end portion 12 as general portions of the intake duct.

  And the axial direction inner end of each small diameter cylinder part 13a, 13a and the axial direction outer end of each medium diameter cylinder part 13b, 13b are provided by integral molding via the first annular vertical wall parts 13d, 13d. Has been. In addition, the inner end in the axial direction of each of the medium diameter cylindrical portions 13b and 13b and the outer end in the axial direction of the large diameter cylindrical portion 13c are continuously provided by integral molding via the second annular vertical wall portions 13e and 13e. Yes.

  The inner duct 2 has an inner diameter equivalent to the inner diameters of the small diameter cylindrical portions 13a and 13a, the first end portion 11 and the second end portion 12, and has an outer diameter equivalent to the inner diameter of the medium diameter cylindrical portions 13b and 13b. It has a cylindrical shape. In addition, a plurality of slit portions 21 extending in the circumferential direction are formed in the central portion of the inner duct 2 in the axial direction. Note that the number and size of the slit portions 21 can be set as appropriate.

  The inner duct 2 is made of a hard resin and is molded in advance into a predetermined shape by injection molding. The material of the hard resin is not particularly limited, and for example, PP (polypropylene) or PA (polyamide) can be employed. Moreover, the shaping | molding method of the inner duct 2 is not specifically limited, You may shape | mold by blow molding. A metal may be employed as the material for the inner duct 2.

  The inner duct 2 is disposed inside the silencer portion 13 of the duct body 1. Specifically, the outer peripheral surfaces of both end portions in the axial direction of the inner duct 2 are in contact with and held by the inner peripheral surfaces of both medium-diameter cylindrical portions 13b and 13b. Thereby, the inner peripheral surface of the inner duct 2 and the inner peripheral surfaces of the small diameter cylindrical portions 13a and 13a, the first end portion 11 and the second end portion 12 are flush with each other. Further, both end surfaces in the axial direction of the inner duct 2 are in contact with the inner end surfaces in the axial direction of both small diameter cylindrical portions 13a, 13a. Thereby, the inner duct 2 is restricted from moving in the axial direction with respect to the silencer portion 13. A silencer chamber 3 is formed between the inner duct 2 and the large-diameter cylindrical portion 13c of the silencer portion 13 of the duct body 1, and a communication portion 5 is formed to communicate the silencer chamber 13 and the duct interior 4. ing.

  This silencer-equipped intake duct can be manufactured, for example, as follows. First, the inner duct 2 having a predetermined shape is formed in advance by injection molding or blow molding. As shown in FIG. 2, the inner duct 2 is disposed between the split molds 32 and 33 for multilayer three-dimensional blow molding in a state where the inner duct 2 is held by the mandrel 31. In this state, a parison 34 for forming a duct main body made of a predetermined material is inserted and disposed between the divided dies 32 and 33 and the inner duct 2. Then, after the molds 32 and 33 are clamped, air is blown into the parison 34 to perform three-dimensional blow molding. As a result, the duct body 1 composed of the first end portion 11, the silencer portion 13 and the second end portion 12 is integrally formed into a predetermined shape, and at a predetermined position in the duct body 1 (both inner diameters of the silencer portion 13 The inner duct 2 is integrally held on the inner peripheral surfaces of the portions 13b and 13b. Thus, the intake duct with a silencer is completed.

  In the intake duct with a silencer, the inner duct 2 is arranged inside the silencer portion 13 of the duct body 1 in which the first end portion 11 and the second end portion 12 as a general portion and the silencer portion 13 are integrally formed. By being provided, the sound deadening chamber 3 is formed between the large diameter portion 13 c of the silencer portion 13 and the inner duct 2. For this reason, there is no welded joint in the wall that partitions the sound deadening chamber 3. Therefore, strict gap management for preventing sound leakage is not necessary, and there is no concern about sound leakage from the welded joint.

  Further, in this intake duct with a silencer, the outer peripheral surfaces of both end portions in the axial direction of the inner duct 2 are in contact with and held by the inner peripheral surfaces of the medium diameter cylindrical portions 13b, 13b. The inner duct 2 can be held more securely. In addition, since both end surfaces in the axial direction of the inner duct 2 are in contact with the inner end surfaces in the axial direction of both small-diameter cylindrical portions 13a, 13a, the axial movement of the inner duct 2 with respect to the silencer portion 13 is restricted. . For this reason, the play of the inner duct 2 in the silencer part 13 can be regulated reliably.

  Furthermore, in this intake duct with a silencer, since the slit portion 21 is formed in the inner duct 2 in advance, the communication portion 5 that allows the silencer chamber 3 and the duct interior 4 to communicate with each other can be easily formed.

  In addition, in this intake duct with a silencer, the inner diameter of the inner duct 2 is equal to the inner diameters of the small-diameter cylindrical portions 13a and 13a, the first end portion 11 and the second end portion 12, and the inner duct 2 and the small-diameter The inner peripheral surfaces of the cylinder portions 13a, 13a, the first end portion 11 and the second end portion 12 are flush with each other. For this reason, the flow of air flowing through the air flow path inside the duct 4 becomes smooth. Therefore, it is advantageous to suppress the pressure loss due to the turbulent flow generated in the air flow path inside the duct 4.

  Moreover, in this intake duct with a silencer, since the duct main body 1 is integrally formed by multilayer three-dimensional blow molding, the first end portion 11 and the second end portion 12 that constitute the duct main body 1 and the silencer are silenced. The vessel portion 13 can be easily integrally formed. And since the inner duct 2 is held by the medium-diameter cylindrical portion 13b of the duct body 1 at the same time as the duct body 1 is multilayered and three-dimensional blow-molded, the coupling structure is simple and no complicated assembly process is required. .

  Furthermore, since the first end portion 11 and the second end portion 12 as the general portion are made of a soft resin, it is easy to ensure assembly and airtightness in the first fastening portion 11a and the second fastening portion 12a. At the same time, the vibration-proof performance can be effectively ensured in the bellows portion 12b. On the other hand, since the silencer unit 13 is made of a hard resin, the sound emitted from the wall surface of the silencer unit 13 can be more reliably suppressed.

(Embodiment 2)
In the intake duct with a silencer of the present embodiment shown in FIG. 3, the communication portion 5 is formed by a gap portion instead of the slit 21.

  That is, the inner duct 2 in the silencer-equipped intake duct has a cylindrical shape whose axial length is shorter by a predetermined amount than the inner duct 2 in the first embodiment. Only one end portion in the axial direction of the inner duct 2 is held by one of the silencer portions 13 (on the left side in FIG. 3) at the middle diameter cylindrical portion 13 b. Specifically, the outer peripheral surface of one end portion in the axial direction of the inner duct 2 is in contact with and held by substantially the entire inner peripheral surface of the medium diameter cylindrical portion 13. Thus, the gap 22 is formed between the axial outer end on the other axial end side of the inner duct 2 and the axial inner end of the other middle diameter cylinder portion 13b of the silencer portion 13 (right side in FIG. 3). The gap portion 22 forms a communication portion 5 that allows the sound deadening chamber 3 and the duct interior 4 to communicate with each other.

  Therefore, in this intake duct with a silencer, the axial end portion of the inner duct 2 having a predetermined length is held with respect to the medium-diameter cylindrical portion 13b of the silencer portion 13 of the duct body 1 to have a predetermined size. The communication part 5 can be formed easily.

  Other configurations and operational effects are the same as those of the first embodiment.

(Embodiment 3)
The inner duct 2 in the intake duct with a silencer of the present embodiment shown in FIG. 4 has an annular reinforcing wall portion 23 that integrally projects in the centrifugal direction from the outer peripheral surface on one end side in the axial direction of the inner duct 2. .

  The reinforcing wall portion 23 has a vertically formed vertical wall portion 23a and a lateral wall portion 23b. The vertical wall portion 23 a of the reinforcing wall portion 23 abuts on the inner surface of the second annular vertical wall portion 13 e of the silencer portion 13, and the horizontal wall portion 23 b of the reinforcing wall portion 23 contacts the inner surface of the large diameter portion 13 c of the silencer portion 13. It touches.

  In this intake duct with a silencer, the large-diameter cylindrical portion 13c and the second annular vertical wall portion 13e that are likely to be thin when the duct body 1 is three-dimensionally blow-molded are reinforced by the reinforcing wall portion 23. Noise generated by the pulsation of the wall portion of the portion 13 can be suppressed.

  Other configurations and operational effects are the same as those of the first embodiment.

(Embodiment 4)
The intake duct with a silencer of the present embodiment shown in FIG. 5 includes a first end portion 11 and a second end portion 12 as general portions of the intake duct in the tact body 1 in the intake duct with a silencer of the first embodiment. And the silencer part 13 are formed separately.

  That is, the duct main body 1 in the intake duct with the silencer is made of a soft resin, and the first end portion 11 and the second end portion 12 and the silencer portion 13 made of a hard resin are separately molded, and then the first end. The part 11 and the second end part 12 and the silencer part 13 are fastened. The molding method of the first end portion 11, the second end portion 12, and the silencer portion 13 is not particularly limited, and injection molding, three-dimensional blow molding, or the like can be used.

  One (the left side in FIG. 5) first end portion 11 disposed on one end side in the axial direction of the duct body 1 has a large-diameter end portion 11c on the inner end side in the axial direction. The large-diameter end portion 11c is covered on substantially the entire outer peripheral surface of one of the silencer portions 13 (left side in FIG. 5) of the small-diameter cylindrical portion 13a. A fastener 14 such as a clamp or a band is fastened to the outer peripheral surface of the large diameter end portion 11c. Further, the other second end portion 12 (on the right side in FIG. 5) disposed on the other axial end side of the duct body 1 has a large-diameter end portion 12 c on the axial inner end side. The large-diameter end portion 12c is covered with substantially the entire outer peripheral surface of the other small diameter cylindrical portion 13a (right side in FIG. 5) of the silencer portion 13. A fastener 14 such as a clamp or a band is fastened to the outer peripheral surface of the large diameter end 12c.

  This silencer-equipped intake duct can be manufactured, for example, as follows. First, the inner duct 2 having a predetermined shape and the first end portion 11 and the second end portion 12 having a predetermined shape are formed in advance by injection molding or blow molding. And this inner duct 2 is arrange | positioned between the split molds for three-dimensional blow molding in the state which hold | maintained the inner duct 2 with the mandrel. In this state, a muffler part molding parison made of a predetermined material is inserted and arranged between the split mold and the inner duct 2. Then, after the mold is clamped, air is blown into the parison to perform three-dimensional blow molding. As a result, the silencer unit 13 is integrally formed in a predetermined shape, and the inner duct 2 is integrally formed at a predetermined position in the silencer unit 13 (inner peripheral surfaces of both the inner diameter portions 13b and 13b of the silencer unit 13). To hold. Thereafter, the small-diameter cylindrical portions 13a and 13a of the silencer portion 13 are covered with the large-diameter end portion 11c of the first end portion 11 and the large-diameter end portion 12c of the second end portion 12, and the outer peripheral surfaces of the large-diameter end portions 11c and 12c. Fastener 14 is fastened. Thus, the intake duct with a silencer is completed.

  Other configurations are the same as those of the first embodiment. Therefore, the intake duct with a silencer basically has the same effects as those of the first embodiment.

It is sectional drawing which shows the whole structure of the air intake duct with a silencer which concerns on Embodiment 1 of this invention. It is sectional drawing explaining the manufacturing method of the air intake duct with a silencer which concerns on Embodiment 1 of this invention. It is a fragmentary sectional view which shows the structure of the air intake duct with a silencer which concerns on Embodiment 2 of this invention. It is a fragmentary sectional view which shows the structure of the air intake duct with a silencer which concerns on Embodiment 3 of this invention. It is a fragmentary sectional view which shows the structure of the air intake duct with a silencer which concerns on Embodiment 4 of this invention. It is sectional drawing which shows the structure of the conventional intake duct with a silencer. It is sectional drawing which shows the structure of the other conventional intake duct with a silencer. It is sectional drawing which shows the structure of the other conventional air intake duct with a silencer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Duct main body 2 ... Inner duct 3 ... Noise reduction chamber 4 ... Duct inside 5 ... Communication part 11 ... 1st edge part (general part)
DESCRIPTION OF SYMBOLS 12 ... 2nd edge part (general part) 13 ... Silencer part 13a ... Small diameter cylinder part 13b ... Medium diameter cylinder part 13c ... Large diameter cylinder part 21 ... Slit 22 ... Gap part

Claims (9)

A pair of small-diameter cylindrical parts connected to the general part of the intake duct and the axially outer ends connected to the axially inner ends of the small-diameter cylindrical parts. A muffler having a pair of large-diameter cylindrical portions having a large diameter, and a large-diameter cylindrical portion having a larger diameter than the intermediate-diameter cylindrical portion, the axially outer ends being connected to the axially inner ends of the respective intermediate-diameter cylindrical portions. The vessel,
An inner member in which at least one of both end portions in the axial direction is held by the medium-diameter cylindrical portion to form a silencing chamber between the large-diameter cylindrical portion and a communication portion that communicates the silencing chamber and the inside of the duct. And an air intake duct with a silencer.   2. The intake duct with a silencer according to claim 1, wherein both end portions in the axial direction of the inner duct are held by both of the medium-diameter cylindrical portions, and the communication portion includes a slit portion formed in advance in the inner duct.   The intake duct with a silencer according to claim 2, wherein both axial end surfaces of the inner duct are in contact with axially inner end surfaces of the small-diameter cylindrical portions.   One end portion in the axial direction of the inner duct is held by one of the medium diameter cylindrical portions, and the communication portion includes an axial outer end of the other axial end portion of the inner duct and a shaft of the other medium diameter cylindrical portion. The intake duct with a muffler according to claim 1, comprising a gap formed between the inner end in the direction.   The intake duct with a silencer according to any one of claims 1 to 4, wherein an inner diameter of the inner duct and an inner diameter of the small-diameter cylindrical portion are substantially the same.   The air intake with a silencer according to any one of claims 1 to 5, wherein the inner duct has a reinforcing wall portion that protrudes integrally from an outer surface of the inner duct in a centrifugal direction and abuts against an inner surface of the large-diameter cylindrical portion. duct.   The intake duct with a silencer according to any one of claims 1 to 6, wherein the general part is made of a soft resin, and the silencer part is made of a hard resin harder than the soft resin.   The intake duct with a silencer according to any one of claims 1 to 7, further comprising a duct main body in which the general part and the silencer part are integrally formed by three-dimensional blow molding. A duct main body having a general part of the intake duct, a silencer part integrally formed with the general part by three-dimensional blow molding, and having a large diameter cylindrical part larger than the general part;
A muffler comprising: an inner duct that is disposed inside the large-diameter cylindrical portion, forms a noise-reducing chamber between the large-diameter cylindrical portion, and forms a communication portion that communicates the noise-reducing chamber and the inside of the duct. A method of manufacturing a suction duct with a vessel,
Arranging the inner duct in a mold for three-dimensional blow molding, and inserting and arranging a parison for molding the duct body between the inner duct and the mold, and
A mold clamping step of clamping the mold;
A blow process for blowing the air into the parison to three-dimensionally blow the duct body and holding the inner duct in the silencer section. Method.

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