JP2012092679A - Film type silencing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film type silencing mechanism comprising an oscillatable film member for noise reduction with an excellent endurance.SOLUTION: The film type silencing mechanism 20 has a structure provided outside the duct 10 linking between a pair of transmission and reception films 21A, 21B disposed on a pair of circular through holes 13, 13 formed in a duct 10 with a seesaw member 22. Inner side limiting members 34, 34 face with each other via a clearance 34S with respect to the inner surface of the pair of transmission and reception films 21A, 21B. According to the configuration, the pair of the transmission and reception films 21A, 21B in general oscillates in the clearance 34S for reducing noise. In the case a large negative pressure is applied in the duct 10, the pair of transmission and reception films 21A, 21B deformed inward by the negative pressure come in contact with the inner side limiting members 34 for preventing excessive deformation. Thereby, decline of the silencing performance of the film type silencing mechanism 20 is prevented so as to improve the endurance.

Description

  The present invention relates to a membrane type silencing mechanism including a membrane member that can vibrate for noise reduction.

  2. Description of the Related Art Conventionally, as this type of membrane-type silencer mechanism, there has been known one provided with a membrane member stretched on a wall hole formed in a duct wall of an intake duct (see, for example, Patent Documents 1 and 2).

JP 2008-25472 A (FIG. 1) Japanese Patent Laid-Open No. 10-281027 (paragraph [0011], FIG. 2)

  However, in the conventional membrane type silencing mechanism described above, when a large negative pressure is applied in the intake duct, the membrane member may be deformed excessively until it is plastically deformed, resulting in a situation where the silencing performance is lowered.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a membrane-type silencer mechanism having excellent durability.

  In order to achieve the above object, a membrane type silencing mechanism according to the invention of claim 1 is a membrane type silencing mechanism provided with a membrane member stretched in a wall hole penetrating a duct wall of an air intake duct. It is characterized in that it has a grid-like, net-like, cross-like or beam-like inner regulating member opposed to the inner surface of the inside with a gap.

  According to a second aspect of the present invention, in the membrane type silencing mechanism according to the first aspect, the inward surface of the inner regulating member facing the inner side of the intake duct is shifted to the same plane or the outer side with respect to the inner surface of the intake duct. It is characterized by being placed in a position.

  According to a third aspect of the present invention, in the membrane type sound deadening mechanism according to the first or second aspect, the wall holes are arranged in a circular shape and a pair, and the inner portions of the pair of wall holes are paired. In addition, an inner regulating member is provided for each of the transmission / reception film parts, and the center part of the pair of transmission / reception film parts communicates with each other at an intermediate point between the pair of transmission / reception film parts. It is characterized by having a seesaw member that is rotatably supported.

  According to a fourth aspect of the present invention, in the membrane type silencing mechanism according to the third aspect, the seesaw member is disposed outside the intake duct and is fixed in a state where the tip end portion penetrates the central portion of the wave transmitting / receiving film portion. The inner regulating member is characterized in that an escape hole is provided for avoiding interference with the distal end portion of the seesaw member penetrating the transmitting / receiving film portion.

  According to a fifth aspect of the present invention, in the membrane-type sound deadening mechanism according to any one of the first to fourth aspects, a lattice-like, net-like, cross-shaped, or beam-like structure facing the outer surface of the membrane member with a gap. It is characterized in that an outer regulating member is provided.

[Invention of Claim 1]
In the membrane type silencing mechanism of the first aspect, the inner regulating member faces the inner surface of the membrane member through a gap, and the membrane member vibrates due to the sound wave in the gap. When a large negative pressure is applied in the intake duct, the membrane member deformed inward by the negative pressure comes into contact with the inner regulating member, thereby preventing excessive deformation. The inner regulating member also regulates the contact of foreign matter with the film member. By these, the fall of the silencing performance of a membrane type silencing mechanism is prevented, and durability becomes high.

[Invention of claim 2]
According to the structure of the membrane type silencing mechanism of the second aspect, an increase in the intake resistance due to the inner regulating member is suppressed.

[Invention of claim 3]
In the membrane type silencing mechanism of the third aspect, since the pair of transmission / reception film portions are connected by the seesaw member, when one of the transmission / reception film portions vibrates in response to the sound wave of noise, it is driven. The other transmitting / receiving film part also vibrates, and the bulging direction of one transmitting / receiving film part and the bulging direction of the other transmitting / receiving film part are always opposite to each other. Thereby, a cancel wave having a phase opposite to that of the sound wave of noise received by one of the transmission / reception film parts is transmitted from the other transmission / reception film part, and noise can be reduced. In addition, when a large negative pressure is applied to the intake duct, both of the pair of transmission / reception film portions are greatly pulled inward. Excessive deformation of the transmission / reception film portion can be prevented, and a membrane-type sound deadening mechanism with excellent durability can be provided.

[Invention of claim 4]
In the membrane type sound deadening mechanism according to the fourth aspect, since the tip of the seesaw member is fixed in a state where the tip of the seesaw member penetrates through the center of the wave transmitting / receiving film portion, the seesaw member is firmly fixed to the wave transmitting / receiving film portion. Moreover, by providing the escape hole in the inner regulating member, it is possible to avoid interference between the inner regulating member and the tip of the seesaw member.

[Invention of claim 5]
According to the membrane type silencing mechanism of the fifth aspect, even if the inside of the intake duct is in a pressurized state and the membrane member expands outward, the outer regulating member prevents excessive deformation of the membrane member.

The perspective view of the membrane type sound deadening mechanism concerning a 1st embodiment of the present invention. Perspective view of the membrane silencer with the outer cover removed Disassembled perspective view of intake duct with membrane silencer A perspective view of the lower surface side of the second base plate member Perspective view of central groove and shaft support groove Partial sectional view of the first base plate member and the second base plate member Perspective view of seesaw member Perspective view of the bottom side of the membrane silencer Perspective view of the bottom side of the outer cover The perspective view of the membrane type sound deadening mechanism concerning a 2nd embodiment The perspective view of the implementation goods of this invention Graph of frequency and reduced volume showing results of comparative experiment

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a part of a vehicle intake duct 10 (hereinafter simply referred to as “duct 10”). One end of this duct 10 is connected to the engine 90 side of the vehicle, and guides the air outside the vehicle taken in from the other end to the engine 90. Here, since the duct 10 also serves as a transmission line for transmitting noise from the engine 90, the membrane type silencing mechanism 20 according to the present invention is provided in order to reduce the noise.

  Specifically, the duct 10 is, for example, divided into two upper and lower duct structures 10A and 10B by a horizontal dividing surface 10C including a central axis that has a cylindrical shape extending in the horizontal direction. The duct structural bodies 10A and 10B are formed by injection molding of resin, and are fixed to each other by, for example, vibration welding.

  A part of the duct wall 10 </ b> W that partitions the inside and the outside of the duct 10 bulges upward to form a box-shaped bulging portion 11. The box-shaped bulging portion 11 has a rectangular parallelepiped shape extending in the axial direction of the duct 10. As shown in FIG. 2, the base wall 12 provided at the upper end of the box-shaped bulging portion 11 has a pair of circular penetrations. Holes 13 and 13 (corresponding to “wall holes” of the present invention) are provided side by side in the axial direction of the duct 10. The membrane member 15 is stretched so as to close the pair of circular through holes 13 and 13 to form a pair of transmission / reception film portions 21A and 21B, and the pair of transmission / reception film portions 21A and 21B. A membrane type silencing mechanism 20 is configured by communicating between the central portions of the two through a seesaw member 22.

  Specifically, as shown in FIG. 3, the base wall 12 includes, for example, a rectangular flat plate-like first base plate member 31 integrally formed on the upper end of the side wall of the box-shaped bulging portion 11, and the first base plate. The second base plate member 32 has a rectangular shape smaller than the member 31 and is stacked on the upper surface of the first base plate member 31. The pair of circular through holes 13 and 13 have the same diameter, and the pair of circular through holes 13 and 13 penetrates the first and second base plate members 31 and 32 at the same pitch. Is formed.

  As shown in FIG. 4, a pair of rectangular membrane members 15, 15 are laid on the lower surface of the second base plate member 32 so as to close the pair of circular through holes 13, 13. In addition, a plurality of film fixing protrusions 32T protruding from the lower surface of the second base plate member 32 pass through the four corners of each film member 15, and the gap between each film member 15 and the lower surface of the second base plate member 32 is, for example, It is fixed with an adhesive. And the part exposed from a pair of circular through-holes 13 and 13 among the film | membrane members 15 becomes above-described pair transmission / reception film | membrane part 21A, 21B.

  The film member 15 is a rubber or resin sheet, and specific examples of the material thereof include EPDM, TPU, TPO, PVC, and PET. Moreover, the thickness of the membrane member 15 is, for example, about 0.1 to 1.0 [mm].

  As shown in FIG. 3, a central groove 19 is recessed and formed between the pair of circular through holes 13 on the upper surface of the second base plate member 32. Here, a center connecting line L10 (see FIG. 5) connecting the center points of the pair of circular through holes 13, 13, and a membrane member 15 (specifically, a membrane member) orthogonal to the center of the center connecting line L10. 15 and the rotation center line L11 (see FIGS. 5 and 6) included in the substantially same plane, the central groove 19 has the rotation center line L11 as the center axis as shown in FIG. The arc groove has a semicircular bottom surface 19A. Further, the groove inner side surfaces 19B, 19B facing each other in the direction of the center connecting line L10 (see FIG. 5) in the central groove 19 are inclined so that the distance between them increases as the distance from the semicircular bottom surface 19A increases. Further, as shown in FIG. 5, a circular foreign material exclusion hole 19 </ b> C is formed through the central groove 19 at the lowermost center of the semicircular bottom surface 19 </ b> A.

  Shaft support grooves 18 and 18 are recessed and formed on both sides of the central groove 19 on the upper surface of the second base plate member 32. The shaft support grooves 18, 18 are arc-shaped grooves having a width and depth smaller than that of the central groove 19, and have semicircular bottom surfaces 18 A centering on the rotation center line L 11. Communicate. Further, the groove inner side surfaces 18B, 18B facing each other in the direction of the center connecting line L10 in the shaft support groove 18 are opposed to each other in parallel as shown in FIG.

  As shown in FIG. 7, the seesaw member 22 has, for example, a substantially E-shape as a whole and extends from the center in the longitudinal direction of the connecting portion 24 extending along the center connecting line L <b> 10. And a pair of end leg portions 25, 25 hanging from both ends of the connecting portion 24.

  A circular flange 25F projects laterally from an intermediate portion in the vertical direction of each end leg 25, and a round bar-shaped through shaft 25T projects from the center of the lower end surface of the end leg 25. Further, as shown in FIG. 6, the lower end surface of the circular flange 25F is arranged to be included in the same plane as the above-described rotation center line L11. The through shafts 25T and 25T are inserted into center holes 21C and 21C (only one center hole 21C is shown in FIG. 6) formed at the center of the wave transmitting / receiving film portions 21A and 21B. . Further, as shown in FIG. 4, a membrane fixing washer 25W is inserted into the penetrating shaft 25T from below the transmitting / receiving membrane portions 21A and 21B and fixed with an adhesive, and these membrane fixing washer 25W and the circular flange portion 25F are fixed. Are sandwiched between the center portions of the wave transmitting / receiving film portions 21A and 21B.

  As shown in FIG. 7, the center leg 23 includes a pair of large-diameter shafts 23B and 23B projecting from both sides of the tip of the projecting piece 23A suspended from the center of the connecting portion 24 in the width direction. The rotation center shafts 23C and 23C are projected from the front end surfaces of the diameter shafts 23B and 23B. The large-diameter shaft 23B and the rotation center shaft 23C are concentric round bars with the rotation center line L11 as a central axis, and the rotation center shaft 23C is thinner than the large-diameter shaft 23B. The distal end portion of the leg main body 23H composed of the projecting piece portion 23A and the large diameter shafts 23B and 23B is received in the central groove 19, while the pair of rotation center shafts 23C and 23C are the shaft support grooves 18 and 18. Is accepted. As shown in FIG. 6, the rotation center shafts 23C, 23C are supported so as to be slidably contacted with the circular bottom surfaces 18A, 18A of the shaft support grooves 18, 18, and the leg main body 23H is supported by the central groove 19 It is in a state of floating from the inside. As a result, the seesaw member 22 rotates about the rotation center line L11.

  The diameter of the foreign matter exclusion hole 19 </ b> C is larger than the gap between the leg main body 23 </ b> H and the inner surface of the central groove 19.

  As shown in FIG. 3, a plurality of locking pieces 17 hang from the outer edge portions of the four sides of the second base plate member 32. In addition, a triangular locking projection 17A is provided on the outer surface side of the tip of each locking piece 17. Then, the locking piece 17 group is inserted into a plurality of first locking slits 35 </ b> A formed through the first base plate member 31, and each locking projection 17 </ b> A is formed in the first base plate member 31 as shown in FIG. 8. The second base plate member 32 is integrally fixed to the first base plate member 31 by being engaged with the inner surface of the first base plate member 31.

  As shown in FIG. 3, annular protrusions 33, 33 protrude from the upper surface of the first base plate member 31 toward the opening edges of the circular through holes 13, 13 of the second base plate member 32. The inner sides of the annular protrusions 33 and 33 are circular through holes 13 and 13 of the first base plate member 31. In addition, as shown in FIG. 6, in the state where the second base plate member 32 is fixed to the first base plate member 31, the tip surfaces of the annular projections 33, 33 are circular through holes in the second base plate member 32. Membrane members 15 and 15 are sandwiched between the opening edges of 13 and 13. Further, a central rectangular window 36 is formed between the annular protrusions 33, 33 of the first base plate member 31, and a bulging protrusion on the back side of the central groove 19 of the second base plate member 32. 19E enters the central rectangular window 36.

  As shown in FIG. 3, an inner regulating member 34 is provided inside the circular through holes 13, 13 in the first base plate member 31. Each inner regulating member 34 is, for example, a plurality of beam portions 34 </ b> C extending toward the center of the circular through hole 13 from a position where the inner peripheral surface of the circular through hole 13 is equally divided into eight, and a concentric circle with the circular through hole 13. The first annular portion 34A that communicates between the distal ends of the beam portions 34C group and the second annular portion 34B that communicates between the intermediate portions of the beam portion 34C group. Further, the inside of the first annular portion 34A corresponds to the “relief hole” according to the present invention, and the inner diameter of the first annular portion 34A is larger than the outer diameter of the membrane fixing washer 25W as shown in FIG. Yes. Thereby, interference with the membrane fixing washer 25W and the inner side regulating member 34 is avoided.

  Further, the inner regulating member 34 is located in the middle of the circular through hole 13 of the first base plate member 31 in the axial direction, and is opposed to the inner surfaces of the wave transmitting / receiving film portions 21A and 21B via a gap 34S. . The gap 34S has a size that allows vibrations of the transmission / reception film portions 21A and 21B due to sound. That is, the transmission / reception film portions 21A, 21B are not in contact with the inner regulating member 34 due to the vibration of the transmission / reception film portions 21A, 21B caused by sound. On the other hand, the gap 34 </ b> S is set so that the wave transmitting / receiving film portions 21 </ b> A, 21 </ b> B come into contact with the inner regulating member 34 when bulging and deforming inside the wave transmitting / receiving film portions 21 </ b> A, 21 </ b> B due to the negative pressure in the duct 10. ing.

  Furthermore, the inward surface 34 </ b> N facing the inside of the duct 10 in the inner regulating member 34 is shifted outward from the inner surface 10 </ b> N of the duct 10. That is, the inner regulating member 34 is prevented from projecting inward from the inner surface 10N of the duct 10, thereby suppressing an increase in intake resistance in the duct 10 by the inner regulating member 34.

  As shown in FIG. 1, the outer surface of the membrane silencer mechanism 20 is covered with an outer surface cover 27. As shown in FIG. 9, the outer surface cover 27 has a rectangular parallelepiped structure that is open at the entire bottom surface and is flat in the vertical direction, and its planar shape is slightly larger than the second base plate member 32, and the first base plate member 31. It is a slightly smaller rectangle. A plurality of locking pieces 28A are suspended from the opening edge on the short side of the rectangular opening 27A on the bottom surface of the outer cover 27, while a plurality of abutting pieces 28B are suspended from the opening edge on the long side. Yes. The abutting piece 28B has a projecting piece shape with a flat bottom surface, and the locking piece 28A extends downward from the abutting piece 28B and is latched in the same manner as the locking projection 17A of the locking piece 17. A protrusion 28T is provided on the outer surface. Then, as shown in FIG. 8, the tip end surface of the abutting piece 28 </ b> B is abutted against the upper surface of the first base plate member 31, and the locking pieces 28 </ b> A and 28 </ b> A are formed through the first base plate member 31. The locking projections 28 </ b> T are inserted into the locking slit 35 </ b> B and locked to the inner surface of the first base plate member 31, whereby the outer surface cover 27 is fixed to the first base plate member 31.

  Further, as shown in FIG. 9, a pair of ceiling ribs 29L and 29L extending in the same direction as the seesaw member 22 are provided on the inner upper surface of the outer surface cover 27, and one pair from the center of the ceiling ribs 29L and 29L. The non-sticking protruding pieces 29 and 29 are suspended. The retaining protrusions 29 and 29 are abutted against the upper surface of the second base plate member 32 (not shown) in a state of crossing the upper surface openings of the shaft support grooves 18 and 18 in the second base plate member 32. Thus, the rotation center shafts 23C, 23C are prevented from coming off in the shaft support grooves 18, 18.

  This completes the description of the configuration of the membrane silencer mechanism 20 of the present embodiment. Next, the function and effect of the membrane type silencing mechanism 20 will be described. The engine 90 operates by taking in air through the duct 10. Then, the intake sound from the engine 90 becomes noise and travels in the duct 10 in the direction opposite to the intake direction, and the noise can be reduced by the membrane-type silencer mechanism 20. The silencer mechanism is as follows.

  That is, since the sound wave is a wave whose pressure changes in a predetermined cycle, when one sound wave transmitting / receiving film portion 21A receives the sound wave of noise, the wave wave part 21A bulges inward and bulges outward at the frequency of the noise. It vibrates to repeat the state alternately. Here, since the transmission / reception film parts 21A and 21B are connected to each other by the seesaw member 22, when one of the transmission / reception film parts 21A receives a sound wave of noise and vibrates in a predetermined cycle, the other transmission / reception film part 21A follows the other. The transmitting / receiving film part 21B also vibrates at the same predetermined period, and the bulging direction of one transmitting / receiving film part 21A and the bulging direction of the other transmitting / receiving film part 21B are always opposite to each other. Accordingly, a cancel wave having a phase opposite to that of the sound wave of noise received by one of the transmission / reception film units 21A is transmitted from the other transmission / reception film unit 21B, and noise can be reduced. Moreover, since the membrane silencer mechanism 20 of this embodiment does not have an electrical circuit for generating a cancel wave, it does not require conventional dustproofing, waterproofing and wiring processing, and can be installed in a vehicle at low cost.

  Here, for example, when a foreign object such as a plastic bag sticks to the front surface of the traveling vehicle and the suction port of the duct 10 is covered, the negative pressure in the duct 10 rapidly increases, and the wave transmitting / receiving film portion 21A, 21B is pulled inward. However, in the membrane type silencing mechanism 20 of the present embodiment, since the inner regulating members 34 are opposed to the inner surfaces of the wave transmitting / receiving film portions 21A, 21B, the wave transmitting / receiving wave deflected by the negative pressure in the duct 10 is used. The membrane portions 21A and 21B abut against the inner regulating members 34 and 34, and excessive deformation of the wave transmitting and receiving membrane portions 21A and 21B is prevented. Then, when the plastic bag is removed and the inside of the duct 10 is returned to the normal negative pressure state, the wave transmitting / receiving film portions 21A and 21B are separated from the inner regulating members 34 and 34 so that they can vibrate against noise. Return. Thereby, the fall of the sound deadening performance of the membrane type sound deadening mechanism 20 is prevented, and durability is improved. Further, since the inner regulating members 34 and 34 prevent foreign matter (for example, tools during maintenance) from colliding with the wave transmitting / receiving film portions 21A and 21B, also in this respect, the silencing performance of the membrane silencing mechanism 20 is deteriorated. Is prevented and durability is improved.

  Furthermore, in the membrane type silencing mechanism 20 of the present embodiment, as shown in FIG. 6, the foreign body exclusion hole 19 </ b> C is provided at the bottom of the central groove 19 that receives the central leg portion 23 of the seesaw member 22. Even if dust or the like enters the gap between the center groove 19 and the central groove 19, the negative pressure in the duct 10 is received and the dust or the like is removed from the foreign matter exclusion hole 19C into the duct 10 to prevent dust from accumulating. Can be removed. Thereby, the seesaw member 22 is maintained in a state in which the seesaw member 22 can be smoothly rotated, and also in this respect, the deterioration of the silencing performance is prevented and the durability is improved.

[Second Embodiment]
As shown in FIG. 10, the membrane-type silencer mechanism 20 </ b> V of the present embodiment has an outer restriction member 34 </ b> V having the same shape as the inner restriction member 34 of the first base plate member 31, and the circular through hole 13 of the second base plate member 32. , 13 is provided so as to cover from above, and is fixed to the upper surface opening edge of each circular through hole 13 in the second base plate member 32. Similarly to the inner regulating member 34, each outer regulating member 34 </ b> V does not come into contact with the transmission / reception film portions 21 </ b> A and 21 </ b> B that are vibrated due to sound, and the outer regulating member 34 </ b> V It comes into contact with the wave-transmitting / receiving film portions 21A and 21B which have been deformed. The other configuration is the same as that of the first embodiment.

  According to the membrane type silencing mechanism 20V of the present embodiment, even if the inside of the duct 10 is in a pressurized state and the wave transmitting / receiving film parts 21A, 21B bulge outward, the outer restricting member 34V causes the wave transmitting / receiving film parts 21A, 21B to Excessive deformation is prevented.

[Example]
In the following, the effect product 1 of the present invention and the comparison product 1 excluding the “inner regulation member” according to the present invention from the implementation product 1, and the effect of the silencing effect due to the provision of the “inner regulation member” will be described. An experiment to investigate was conducted. As shown in FIG. 11, the implementation product 1 has a membrane-type noise reduction similar to that of the first embodiment at a position close to the end in the longitudinal direction in the duct 10 having an overall length L1 of 400 [mm] and an inner diameter D3 of φ56 [mm]. A structure including the mechanism 20 is formed. The diameters of the transmission / reception films 21A and 21B (that is, the diameters of the circular through-holes 13 and 13) D1 and D2 in the membrane type silencing mechanism 20 are both φ55 [mm], and between the center points of the transmission / reception films 21A and 21B. The distance L3 is 65 [mm], and the distance L2 from the end of the duct 10 to the center position between the center points of the transmission / reception films 21A and 21B is 100 [mm]. The wave transmitting / receiving films 21A and 21B are both made of TPO having a film thickness of 0.3 [mm]. Then, a metal mesh having an aperture ratio of 70% was used as the inner regulating members 34, 34, and the gap 34S between the transmission / reception films 21A, 21B and the inner regulating members 34, 34 was set to 1.5 [mm]. . On the other hand, as described above, the comparative product 1 has a structure in which the inner regulating members 34 and 34 are excluded from the film-type silencer mechanism 20 of the implementation product 1.

(experimental method)
The experimental method is as follows.
(1) As shown in FIG. 11, the speaker 92 is disposed opposite to the opening of the start end of the duct 10 in the embodiment product 1, and the start microphone 91 </ b> A and the end microphone 91 </ b> B are disposed at the start end and the end of the duct 10. If the frequency of the sound output from the speaker 92 is changed in the range of 50 to 800 [Hz], the sound is picked up by the start microphone 91A and the end microphone 91B. Then, a differential volume obtained by subtracting the picked-up sound volume by the start microphone 91A from the picked-up sound volume by the terminal microphone 91B is obtained for each frequency, and the graph g1 shown in FIG. 12 is created. Further, in the same procedure, the graph g2 of FIG. 12 is created using the comparative product 1 instead of the implementation product 1.

(2) A suction device is connected to the end opening of the duct 10 of the embodiment product 1 on the side away from the membrane-type silencing mechanism 20, and while suctioning 6.5 [m ³ / min], the other end side The opening is closed by hand for 10 seconds, and the transmission / reception films 21A, 21B are pressed against the inner regulating members 34, 34. Thereafter, it is visually confirmed whether the transmission / reception films 21A, 21B return to the original state.

(Experimental result)
Since the graphs g1 and g2 in FIG. 12 substantially coincided with each other, it was confirmed that there was almost no influence on the silencing effect due to the provision of the inner regulating members 34 and 34. Further, even if the wave transmitting / receiving films 21A, 21B are pressed against the inner regulating members 34, 34, they are returned to the original state without being plastically deformed, and therefore the wave receiving films 21A, 21B are excessively deformed by the inner regulating members 34, 34. It was confirmed that there was a preventive effect.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) In the said 1st and 2nd embodiment, the example which applied this invention to the membrane-type silencer mechanism 20 and 20V which connected between the pair of wave transmission / reception film | membrane parts 21A and 21B with the seesaw member 22 was shown. However, the present invention may be applied to any membrane type silencing mechanism as long as the membrane type silencing mechanism is provided with a membrane member stretched on the wall hole of the intake duct.

  (2) Although the inner regulating member 34 and the outer regulating member 34V in the film-type silencer mechanisms 20 and 20V of the first and second embodiments are lattice-shaped, they may be mesh-shaped. Further, the inner regulating member 34 and the outer regulating member 34V may be in the form of a cantilever beam that crosses the circular through hole 13 or a cantilever beam that projects inward from the edge of the circular through hole 13. There may be. Furthermore, when the inner regulating member and the outer regulating member are formed in a beam shape, the beam may be a single beam or a plurality of beams may be formed in a beam shape.

  (3) In the first embodiment, the seesaw member 22 that communicates between the transmission / reception film portions 21A and 21B is disposed outside the duct 10, but may be disposed inside the duct. However, since the seesaw member can be rotated by the wind pressure in the duct, it is preferable to dispose the seesaw member outside the duct.

  (4) In the first embodiment, the duct 10 is provided with only the membrane silencer mechanism 20 according to the present invention. However, a conventional known silencer mechanism and the silencer mechanism according to the present invention are combined to form an intake duct. May be provided.

DESCRIPTION OF SYMBOLS 10 Duct 10N Inner surface 10W Duct wall 15 Membrane member 20, 20V Membrane type silencer mechanism 21A, 21B Transceiving membrane portion 22 Seesaw member 34 Inner regulating member 34N Inward surface 34S Gap 34V Outer regulating member 36 Central rectangular window

Claims (5)

A membrane type silencing mechanism provided with a membrane member stretched in a wall hole penetrating the duct wall of the intake duct,
A film-type sound deadening mechanism comprising a lattice-shaped, net-shaped, cross-shaped, or beam-shaped inner regulating member facing the inner surface of the film member with a gap therebetween.   The inward surface of the inner regulating member facing the inner side of the intake duct is disposed at a position that is flush with or out of the inner surface of the intake duct. Membrane silencer. The wall holes are arranged in a circle and in a pair, and the inner portions of the pair of wall holes in the film member are used as a pair of wave transmitting / receiving film parts, and the inner regulation is performed for each wave transmitting / receiving film part. While providing members,
3. A seesaw member that communicates between the center portions of the pair of transmission / reception film portions and is rotatably supported at an intermediate point between the pair of transmission / reception film portions. The membrane-type silencer mechanism described in 1. The seesaw member is disposed outside the intake duct and is fixed in a state where a tip portion is passed through a central portion of the wave transmitting / receiving film portion,
4. The membrane-type silencer according to claim 3, wherein the inner regulating member is provided with an escape hole for avoiding interference with a tip portion of the seesaw member penetrating the wave transmitting / receiving film portion. mechanism.   The film according to any one of claims 1 to 4, further comprising a lattice-shaped, net-shaped, cross-shaped, or beam-shaped outer regulating member facing the outer surface of the film member via a gap. Expression silencer.