JP2015004755A - Silencer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silencer that allows a sufficient blowing feeling and produces a high silence effect.SOLUTION: A silencer 1 includes: a housing including a barrel part 11 having a substantially conical pipe shape and a dish-shaped bottom 12 bonded to a large-diameter-side end 11a of the barrel part 11; and an exhaustion pipe 20. The exhaustion pipe 20 includes an upstream part 21, expansion part 22, and downstream part 23, and the inner diameter of the expansion part 22 is larger than the inner diameters of the upstream part 21 and downstream part 23. The expansion part 22 serves as a silence chamber. The exhaustion pipe 20 is accommodated in the barrel part 11, and is fixed to an edge of a through hole 33 disposed in the center of the bottom 12. When the silencer 1 is mounted to a bell 3, the axis of the exhaustion pipe 20 is parallel with that of the bell 3.

Description

  The present invention relates to a silencer.

  A silencer used for the purpose of reducing the volume of a wind instrument such as a trumpet is disclosed in Patent Document 1, for example.

  FIG. 9 is a longitudinal sectional view showing the structure of the silencer of Patent Document 1. The silencer A1 of Patent Document 1 includes a cylindrical container A2 having one bottom surface opened and the other bottom surface closed, and a conical partition body A10 having a bottom portion opened. The partition wall A10 is housed inside the container A2, and the peripheral edge A10b of the partition wall A10 is fixed to the inner wall near the opening end A7 of the container A2 so that the top part A10a of the partition wall A10 does not contact the inner wall A2a of the container A2. Has been. A salan A6 that protects the inside of the container A2 is stretched at the opening end A7 of the container A2, and a cavity A11 that functions as a first silencing chamber is formed by the inner wall of the partition wall A10 and the salan A6. . Further, a cavity A13 that functions as a second silencing chamber is formed between the inner wall of the container A2 and the outer wall of the partition wall A10. In the silencer A1, the opening end A7 of the container A2 is fixed to the end A8a of the bell A8 of the wind instrument by the fixing tool A9. The exhaled breath that has entered the cavity A11 (first silencer chamber) of the silencer A1 from the bell A8 is guided to the cavity A13 (second silencer chamber) through the vent hole A14 provided near the top A10a of the partition wall A10. The exhaled air introduced into the cavity A13 (second silencing chamber) is discharged to the space outside the silencer A1 through the vent hole A15 provided in the vicinity of the opening end A7 of the container A2. The silencer A1 has a large silencing effect by providing first and second silencing chambers.

JP-A-57-53792

  However, since the silencer A1 of Patent Document 1 has a complicated exhalation path until it is discharged to the space outside the silencer A1, the exhalation is not smoothly discharged to the space outside the silencer, and the silencer A1. There is a problem that there is a feeling of suffocation when the instrument is mounted on a wind instrument and played (ie, the feeling of blowing is not good).

  The present invention has been made in view of the circumstances as described above, and an object thereof is to provide a silencer which has a good feeling of wind and has a great silencing effect.

  The present invention has a casing having a through hole, which is fixed to the bell of the wind instrument, and both ends open, one end of which is fixed to the through hole of the casing, and the space inside the bell and the bell A hollow exhaust pipe that communicates with an outer space, and a muffler chamber that is formed by enlarging a cross-sectional area in the exhaust pipe in the middle of the exhaust pipe and communicates with the space in the exhaust pipe And a muffler characterized by comprising:

  According to the present invention, exhaled air in the space inside the bell passes through the hollow exhaust pipe and is discharged to the space outside the bell. Further, since the space inside the bell communicates with the inside space of the silencer chamber formed in the middle of the exhaust pipe, the sound wave generated in the space inside the bell is guided to the inside space of the silencer chamber. Since the sound deadening chamber has an enlarged cross-sectional area in the exhaust pipe, a part of the sound wave is reflected at the boundary between the space in the exhaust pipe and the inner space of the sound deadening chamber, and in the inner space of the sound deadening chamber. The traveling wave and the reflected wave interfere with each other, reducing the energy of the sound wave. Therefore, it is possible to realize a silencer that has a good feeling of blowing and has a large silencing effect.

  The present invention also includes a housing having a through hole, which is fixed to the bell of the wind instrument, both ends open, one end of which is fixed to the through hole of the housing, and the space inside the bell and the A hollow exhaust pipe that communicates with a space outside the bell; and a silencing chamber that is a partitioned space surrounding the exhaust pipe, and the space in the exhaust pipe communicates with the inner space of the silencing chamber A silencer having a through hole on a side surface of the exhaust pipe is provided.

  According to the present invention, exhaled air in the space inside the bell passes through the hollow exhaust pipe and is discharged to the space outside the bell. In addition, since the space in the exhaust pipe and the inner space of the silencer chamber, which is a partitioned space surrounding the exhaust pipe, communicate with each other through the through hole provided on the side surface of the exhaust pipe, the diameter of the through hole and the volume of the silencer chamber Helmholtz resonance based on That is, the sound pressure level of sound waves that pass through the exhaust pipe from the space inside the bell and radiate to the space outside the bell attenuates in the vicinity of the Helmholtz resonance frequency. Therefore, it is possible to realize a silencer that has a good feeling of blowing and has a large silencing effect.

It is the longitudinal cross-sectional view and front view which show the structure of the silencer 1 by 1st Embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the silencer 1A by 2nd Embodiment of this invention. It is a see-through | perspective perspective view which shows the structure of the silencer 1B by 3rd Embodiment of this invention. It is a see-through | perspective perspective view which shows the structure of the silencer 1C by 4th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the silencer 1D by the modification (2) of this invention. It is a longitudinal cross-sectional view which shows the structure of the silencer 1E by the modification (3) of this invention. It is a longitudinal cross-sectional view which shows the structure of the silencer 1F by the modification (4) of this invention. It is a longitudinal cross-sectional view which shows the structure of the silencer 1G by the modification (5) of this invention. It is a longitudinal cross-sectional view which shows the structure of the silencer of patent document 1.

Embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
FIG. 1 (A) is a longitudinal sectional view showing the configuration of the silencer 1 according to the first embodiment of the present invention, and FIG. 1 (B) is a front view thereof. The silencer 1 according to the present embodiment is a silencer 1 for a trumpet, and FIG. 1 shows a state in which the silencer 1 is attached to the trumpet. The silencer 1 according to the present embodiment is provided with an exhaust pipe 20 having an inflating portion 22 inside a casing composed of a trunk portion 11 and a bottom portion 12, thereby increasing the silencing effect while improving the feeling of blowing. The housing and the exhaust pipe 20 are formed by molding plastic, for example.

  The body 11 is a conical tubular body having a cavity 13 therein. The body 11 has an outer diameter and an inner diameter that are reduced along the inner wall of the bell 3 of the trumpet from the large-diameter end 11a that is the front end toward the small-diameter end 11b that is the rear end. A certain small diameter side end 11b is open. A mounting portion 14 made of a flexible material is provided on the outer surface of the body portion 11 near the small-diameter side end 11b. The silencer 1 is inserted into the bell 3 of the trumpet from the small diameter end 11b side which is the rear end. The body 11 is fixed to the inner wall of the bell 3 by the contact of the mounting portion 14 with the inner wall of the bell 3.

  The bottom part 12 is dish-shaped, and the bottom part of the dish is located near the axis of the body part 11. Further, the bottom 12 is joined to the large-diameter side end 11a of the body 11 by an adhesive or the like at the edge of the dish. That is, the bottom portion 12 serves as a closing portion that closes the large-diameter side end 11a that is the front end. The bottom 12 is positioned near the end face of the bell 3 when the body 11 is fixed to the inner wall of the bell 3 of the trumpet. More specifically, the vicinity of the joint between the bottom 12 and the body 11 is located on the end surface of the bell 3, and the bottom 12 is more outward (front side) than the end surface of the bell 3 because the bottom 12 is curved. Protruding.

  The exhaust pipe 20 includes an upstream portion 21, a downstream portion 23, and an expansion portion 22 between the upstream portion 21 and the downstream portion 23. The upstream part 21, the expansion part 22 and the downstream part 23 each have a hollow cylindrical shape, and the axes of the upstream part 21, the expansion part 22 and the downstream part 23 are on the same straight line. The axial length of the upstream portion 21 is longer than the axial length of the downstream portion 23. The inner diameter of the upstream portion 21 and the inner diameter of the downstream portion 23 are the same, and are equal to or larger than the minimum inner diameter of the mouthpiece of the trumpet. The inner diameter of the inflating part 22 is larger than the inner diameters of the upstream part 21 and the downstream part 23. Further, the length of the inflating portion 22 in the axial direction is larger than the inner diameter of the inflating portion 22. Both ends of the upstream portion 21 and the downstream portion 23 are open. That is, both ends of the exhaust pipe 20 are open. The upstream end 22 a of the inflating part 22 is closed except for the through hole 31 having the same diameter as the inner diameter of the upstream part 21, and the edge of the through hole 31 is continuous with the downstream end 21 b of the upstream part 21. The downstream end 22 b of the expansion portion 22 is closed except for the through hole 32 having the same diameter as the inner diameter of the downstream portion 23, and the edge of the through hole 32 is continuous with the upstream end 23 a of the downstream portion 23. Therefore, the inner space of each of the upstream portion 21, the expansion portion 22, and the downstream portion 23 communicates with each other through the through holes 31 and 32, and the cross-sectional area surrounded by the inner wall of the exhaust pipe 20 is from the upstream portion 21. It expands rapidly toward the expansion part 22 and contracts rapidly from the expansion part 22 toward the downstream part 23.

  The exhaust pipe 20 is accommodated in the body 11 so that the axis of the exhaust pipe 20 and the axis of the body 11 are parallel and the outer wall of the exhaust pipe 20 does not contact the inner wall of the body 11. Is done. A through hole 33 having the same diameter as the inner diameter of the downstream portion 23 of the exhaust pipe 20 is provided at the center of the bottom portion 12, and the downstream end 23 b of the downstream portion 23 of the exhaust pipe 20 is connected to the through hole 33 of the bottom portion 12. 11 is fixed from the inner side. For this reason, when the trunk portion 11 is fixed to the bell 3, the exhaust pipe 20 communicates the space inside the bell 3 and the space outside the bell 3 through the space inside the exhaust pipe 20. It plays the role which guides the exhalation in 3 to the space outside the silencer 1 (outside the trumpet). Further, the upstream end 21 a of the upstream portion 21 of the exhaust pipe 20 is located in the vicinity of the end surface of the small diameter side end 11 b of the trunk portion 11. Further, when the trunk portion 11 is fixed to the inner wall of the bell 3 of the trumpet, the axis of the exhaust pipe 20 is substantially parallel to the axis of the bell 3.

In the silencer 1 according to the present embodiment, the cavity 13 formed by the inner wall of the trunk portion 11, the inner wall of the bottom portion 12, and the outer wall of the exhaust pipe 20 functions as a first silencer chamber, and the expansion portion 22 in the exhaust pipe 20 It functions as a second silencing chamber. That is, the silencer 1 according to the present embodiment is characterized in that the exhaust pipe 20 is provided with a silencer chamber (second silencer chamber) communicating with the space inside the exhaust pipe 20. The sound deadening chamber (second sound deadening chamber) provided in the exhaust pipe 20 is formed by enlarging the cross-sectional area in the exhaust pipe 20 in the middle of the exhaust pipe 20. In other words, the noise reduction chamber provided in the exhaust pipe 20 is a space where a part of the outer wall of the exhaust pipe 20 is a side surface of the noise reduction chamber and other than the through holes 31 and 32 are closed.
The above is the configuration of the silencer 1.

  Next, a flow of exhalation and a silencing operation when the silencer 1 according to the present embodiment is attached to a trumpet and played. When the trunk portion 11 is fixed to the bell 3, the silencer 1 closes the bell 3 while leaving the through hole 33 to which the exhaust pipe 20 is fixed. The exhaled air blown from the mouthpiece of the trumpet is introduced into the cavity 13 from the small-diameter side end 11b of the body 11 of the silencer 1 after passing through the trumpet, and the upstream end 21a of the upstream portion 21 of the exhaust pipe 20 Is introduced into the exhaust pipe 20, passes through the exhaust pipe 20, and is discharged into the space outside the silencer 1. At this time, since the axis of the exhaust pipe 20 and the axis of the bell 3 are substantially parallel, the exhaled gas passing through the exhaust pipe 20 and the inner wall of the exhaust pipe 20 (particularly, the upstream portion 21 and the downstream portion 23 having a small inner diameter). There is little resistance to the inner wall), and the exhaled air introduced into the exhaust pipe 20 passes through the exhaust pipe 20 smoothly. Therefore, when the silencer 1 is attached to the trumpet and played, there is no feeling of suffocation and a good feeling of blowing is obtained.

  The sound wave generated by playing the trumpet enters the cavity 13 formed by the inner wall of the trunk portion 11, the inner wall of the bottom portion 12, and the outer wall of the exhaust pipe 20, and from the upstream end 21 a of the upstream portion 21 of the exhaust pipe 20. The exhaust pipe 20 is entered. Here, the cross-sectional area of the cavity 13 gradually increases from the small diameter side end 11b of the body portion 11 toward the large diameter side end 11a. For this reason, the acoustic impedance in the cavity 13 gradually changes along the axis of the trunk portion 11. Thereby, a part of the sound wave traveling from the small diameter side end 11b toward the large diameter side end 11a in the cavity 13 is reflected at each position between the small diameter side end 11b and the large diameter side end 11a. Then, the sound wave traveling from the small diameter side end 11b toward the large diameter side end 11a interferes with the sound wave traveling from the large diameter side end 11a toward the small diameter side end 11b, so that the energy of the sound wave is reduced. Accordingly, the volume is reduced in the cavity 13.

  The sound wave that has entered the exhaust pipe 20 travels in the order in the upstream portion 21, the expansion portion 22, and the downstream portion 23, and is radiated from the through hole 33 in the bottom portion 12 to the space outside the silencer 1. Here, at the boundary between the upstream portion 21 and the expansion portion 22 and the boundary between the expansion portion 22 and the downstream portion 23, the cross-sectional area surrounded by the inner wall of the exhaust pipe 20 changes rapidly, so that the acoustic impedance changes. To do. Therefore, a part of the sound wave traveling from the upstream portion 21 toward the expansion portion 22 is reflected at the boundary between the upstream portion 21 and the expansion portion 22, and downstream from the expansion portion 22 at the boundary between the expansion portion 22 and the downstream portion 23. A part of the sound wave traveling toward the portion 23 is reflected. Further, a part of the sound wave reflected at the boundary between the inflating part 22 and the downstream part 23 is further reflected at the boundary between the upstream part 21 and the inflating part 22. And in the expansion part 22, the sound wave which advances from the upstream end 22a of the said expansion part 22 to the downstream end 22b and the sound wave which advances from the downstream end 22b to the upstream end 22a interfere, and the energy of a sound wave reduces. Therefore, the volume of the sound emitted to the space outside the silencer 1 is reduced.

  As described above, the silencer 1 according to the present embodiment has a housing including the body portion 11 and the bottom portion 12 provided with the through hole 33, and both ends opened, and one end thereof is provided in the bottom portion 12. The exhaust pipe 20 has a hollow exhaust pipe 20 that communicates with the space inside the bell 3 and the space outside the bell 3, and a sound deadening chamber that communicates with the space inside the exhaust pipe 20 is provided in the exhaust pipe. . In addition, the expansion portion 22 that functions as a muffler chamber provided in the exhaust pipe 20 is formed by enlarging the cross-sectional area in the exhaust pipe 20. When the silencer 1 is mounted on the trumpet, the axis of the exhaust pipe 20 is substantially parallel to the axis of the bell 3. Therefore, exhaled air can be discharged smoothly into the space outside the silencer 1, and the exhaust pipe 20 is added to the cavity 13 formed by the inner wall of the trunk portion 11, the inner wall of the bottom portion 12, and the outer wall of the exhaust pipe 20. The energy of the sound wave can be reduced in the inflatable portion 22. Therefore, the volume of the sound emitted to the space outside the silencer 1 can be further reduced and the silencing effect can be further increased while obtaining a good feeling of blowing with little feeling of suffocation.

Second Embodiment
FIG. 2 is a longitudinal sectional view showing the configuration of the silencer 1A according to the second embodiment of the present invention. The silencer 1A according to the present embodiment is different from the silencer 1 according to the first embodiment in that a sound absorbing material 40 such as glass wool is provided on the inner wall of the expansion portion 22 of the exhaust pipe 20.

  In the silencer 1A, a part of the energy of the sound wave that travels from the upstream end 22a to the downstream end 22b in the expansion portion 22 of the exhaust pipe 20 or the downstream end 22b of the expansion portion 22 is reflected and travels from the downstream end 22b to the upstream end 22a. A part of the energy of the sound wave to be absorbed is absorbed by the sound absorbing material 40 provided on the inner wall of the expanding portion 22. For this reason, in addition to the interference between the sound wave traveling from the upstream end 22a to the downstream end 22b and the sound wave traveling from the downstream end 22b to the upstream end 22a, the sound absorbing material 40 can absorb sound wave energy. The volume of the sound emitted to the space outside the silencer 1 can be further reduced, and the silencing effect can be further increased.

  The sound absorbing material 40 is preferably not provided on the inner wall of the upstream portion 21 and the inner wall of the downstream portion 23 of the exhaust pipe 20. This is because if the sound absorbing material 40 is provided on the inner wall of the upstream portion 21 and the inner wall of the downstream portion 23, the flow path of the exhalation becomes narrower and the feeling of suffocation increases.

  In addition, the sound absorbing material 40 is not limited to the aspect in which the sound absorbing material 40 is provided on the inner wall of the expanding portion 22, and the sound absorbing material 40 may be provided on the inner wall of the trunk portion 11, the inner wall of the bottom portion 12 and the outer wall of the exhaust pipe 20. The sound absorbing material 40 may be provided on any of the inner wall of the expanding portion 22, the inner wall of the trunk portion 11, the inner wall of the bottom portion 12, and the outer wall of the exhaust pipe 20.

<Third Embodiment>
FIG. 3 is a perspective view showing the configuration of a silencer 1B according to a third embodiment of the present invention. FIG. 3 shows a state in which the silencer 1B is attached to the trumpet. In the silencer 1 according to the first embodiment, the expansion portion 22 of the exhaust pipe 20 that functions as the second silencer chamber is disposed in the cavity 13 that functions as the first silencer chamber. On the other hand, the silencer 1B according to the present embodiment has a second silencer disposed outside the first silencer.

  The housing of the silencer 1 </ b> B includes a trunk portion 51 and a bottom portion 52. The trunk portion 51 has a conical tubular shape, and its outer diameter and inner diameter decrease linearly from the large-diameter side end 51a that is the rear end toward the small-diameter side end 51b that is the front end. The small-diameter side end 51 b of the body 51 is disc-shaped and is joined and closed to the edge of the bottom 52 that is parallel to a plane perpendicular to the axis of the body 51. That is, the bottom 52 serves as a closing portion that closes the small-diameter side end 51b that is the front end. The large-diameter side end 51 a of the trunk portion 51 is open, and the diameter of the large-diameter side end 51 a is smaller than the diameter of the end face of the bell 3. A mounting portion 58 made of a flexible material is provided on the outer edge of the large-diameter side end 51a of the body portion 51. The silencer 1B is inserted into the bell 3 from the large-diameter side end 51a side which is the rear end. Then, when the attachment portion 58 provided on the outer edge of the large-diameter side end 51 a comes into contact with the inner wall of the bell 3, the trunk portion 51 is fixed to the inner wall of the bell 3.

  A through hole 73 is provided at the center of the bottom 52. A cylindrical pipe 63 having an inner diameter that is the same as that of the through hole 73 is fixed to the edge of the through hole 73 in the direction of the large diameter side end 51 a of the body portion 51. In addition, disk-shaped partition walls 53 and 54 are arranged perpendicular to the axis of the body portion 51 in the vicinity of the position where the axial length of the body portion 51 is equally divided into three in the body portion 51, and these partition walls 53 and Each edge of 54 is fixed to the inner wall of the body 51. Further, through holes 71 and 72 are provided at the centers of the partition walls 53 and 54, respectively. A cylindrical pipe 61 having the same inner diameter as the pipe 63 is inserted and fixed in the through hole 71 of the partition wall 53, and a cylindrical pipe having the same inner diameter as the pipe 63 is inserted in the through hole 72 of the partition wall 54. 62 is inserted and fixed. There are gaps between the pipe 61 and the pipe 62 and between the pipe 62 and the pipe 63, respectively. Further, the upstream end 61 a of the pipe 61 protrudes outward (in the direction of the trumpet) from the end surface of the large-diameter side end 51 a of the body portion 51. The axes of the pipes 61 to 63 are on the same straight line, and when the silencer 1B is mounted on the trumpet, the axes of the pipes 61 to 63 are substantially parallel to the axis of the bell 3. Further, when the silencer 1B is mounted on the trumpet, the partition wall 53 is positioned near the end surface of the bell 3, and each component positioned in the direction of the bottom 52 of the partition wall 53 is located outside (front side) the end surface of the bell 3. Protruding.

In the silencer 1B according to the present embodiment, the cavity 55 formed by the inner wall of the trunk portion 51, the partition wall 53, and the outer wall of the pipe 61 functions as a first silencer chamber, and the inner wall of the trunk portion 51, the partition wall 53, and the partition wall 54. A cavity 56 formed by the outer wall of the pipe 61 and the outer wall of the pipe 62; and a cavity 57 formed by the inner wall of the trunk portion 51, the inner wall of the bottom 52, the partition wall 54, the outer wall of the pipe 62, and the outer wall of the pipe 63. It functions as a second silencing chamber. Therefore, in the silencer 1B, the second silencer is disposed outside the first silencer. The pipes 61 to 63 and the cavities 56 and 57 function as a series of exhaust pipes 60 that guide the exhaled gas in the trumpet to the space outside the silencer 1B and exhaust it. In the exhaust pipe 60, the cross-sectional area surrounded by the inner wall of the exhaust pipe 60 suddenly changes from the cross-sectional area surrounded by the inner wall of the pipe 61 from the pipe 61 to the cavity 56 to the cross-sectional area surrounded by the inner wall of the trunk portion 51. From the cavity 56 to the pipe 62, the cross-sectional area surrounded by the inner wall of the body portion 51 is rapidly reduced from the cross-sectional area surrounded by the inner wall of the pipe 62. In addition, the cross-sectional area surrounded by the inner wall of the exhaust pipe 60 has suddenly expanded from the cross-sectional area surrounded by the inner wall of the pipe 62 from the pipe 62 to the cavity 57 to the cross-sectional area surrounded by the inner wall of the body portion 51. The cross-sectional area surrounded by the inner wall of the body portion 51 from the cavity 57 to the pipe 63 is rapidly reduced from the cross-sectional area surrounded by the inner wall of the pipe 63. That is, the silencer 1B is silenced by enlarging the cross-sectional area in the exhaust pipe 60 in the middle of the exhaust pipe 60 (expanding to the cross-sectional area in the trunk portion 51 with respect to the cross-sectional area in the pipes 61 to 63). The chambers (cavities 56 and 57) are formed. The acoustic impedance changes at the boundary where these cross-sectional areas rapidly expand and contract. The cavity 55 has a cross-sectional area that gradually decreases from the large-diameter end 51 a toward the partition wall 53. For this reason, the acoustic impedance in the cavity 55 gradually changes along the axis of the body portion 51. Moreover, the exhaust pipe 60 is accommodated in the trunk | drum 51 which comprises a housing | casing.
The above is the configuration of the silencer 1B.

  Next, the flow of exhalation and the silencing operation when the silencer 1B according to this embodiment is attached to a trumpet and played will be described. When the body 51 is fixed to the bell 3, the silencer 1B closes the bell 3 while leaving the through hole 73 to which the exhaust pipe 60 is fixed. The exhaled air blown from the mouthpiece of the trumpet passes through the trumpet and is then introduced into the cavity 55 from the large-diameter side end 51a of the body 51 of the silencer 1 and from the upstream end 61a of the pipe 61 to the inside of the pipe 61. To be introduced. The exhaled air introduced into the pipe 61 passes through the pipe 61, the cavity 56, the pipe 62, the cavity 57, and the pipe 63 in this order, and is discharged to the space outside the silencer 1B. At this time, since the axes of the pipes 61 to 63 are substantially parallel to the axis of the bell 3, the resistance between the breath passing through each of the pipes 61 to 63 and the inner wall of each of the pipes 61 to 63 The exhaled air introduced into the pipes 61 to 63 passes smoothly through the pipes 61 to 63. Therefore, when the silencer 1B is attached to the trumpet and played, there is no feeling of suffocation and a good feeling of blowing is obtained.

  Among the sound waves generated by playing the trumpet, some of the sound waves that enter the cavity 55 are reflected at each position between the large-diameter side end 51a and the partition wall 53 where the acoustic impedance gradually changes. Then, the sound wave traveling from the large diameter side end 51a toward the partition wall 53 interferes with the sound wave traveling from the partition wall 53 toward the large diameter side end 51a, and the energy of the sound wave is reduced. Accordingly, the volume is reduced in the cavity 55.

  Of the sound waves generated by playing the trumpet, the sound waves that enter the pipe 61 proceed in the order of the pipe 61, the cavity 56, the pipe 62, the cavity 57, and the pipe 63, and from the through hole 73 of the bottom 52. Radiated to the space outside the silencer 1B. At this time, the boundary between the downstream end 61b of the pipe 61 and the cavity 56, the boundary between the cavity 56 and the upstream end 62a of the pipe 62, the boundary between the downstream end 62b of the pipe 62 and the cavity 57, and the boundary between the cavity 57 and the upstream end 63a of the pipe 63 Since the acoustic impedance changes, a part of the sound wave traveling at these boundaries is reflected. Therefore, in the cavity 56, the sound wave traveling from the downstream end 61b side of the pipe 61 to the upstream end 62a side of the pipe 62 interferes with the sound wave traveling from the upstream end 62a side of the pipe 62 to the downstream end 61b side of the pipe 61. The sound wave that travels from the downstream end 61 b side of the pipe 62 to the upstream end 63 a side of the pipe 63 and the sound wave that travels from the upstream end 63 a side of the pipe 63 to the downstream end 62 b side of the pipe 62 in the cavity 57. The energy of sound waves decreases due to interference. Therefore, the volume of the sound emitted to the space outside the silencer 1B is reduced.

  In this embodiment, the same effect as that of the first embodiment is obtained.

  Moreover, the silencer 1B according to the present embodiment can sufficiently secure the volume of the cavity 55 that functions as the first silencer chamber. For this reason, it is possible to reduce the deviation of the pitch when the silencer 1B is attached to the trumpet and played without attaching the silencer 1B to the trumpet.

<Fourth embodiment>
FIG. 4 is a perspective view showing the structure of a silencer 1C according to the fourth embodiment of the present invention. FIG. 4 shows a state in which the silencer 1C is attached to the trumpet. The silencer 1C according to the present embodiment is different from the silencer 1B according to the third embodiment in that an exhaust pipe 80 is used instead of the pipes 61 to 63 (see FIG. 3).

  The exhaust pipe 80 of the silencer 1 </ b> C is a cylindrical pipe that is inserted and fixed in both the through hole 71 of the partition wall 53 and the through hole 72 of the partition wall 54. Further, the downstream end 80 b of the exhaust pipe 80 is fixed to the edge of the through hole 73 of the bottom 52. A cavity 91 is formed by the inner wall of the body portion 51, the partition walls 53 and 54, and the outer wall of the exhaust pipe 80 so as to surround the exhaust pipe 80, and the inner wall of the body portion 51, the inner wall of the bottom 52, the partition wall 54, and the exhaust pipe 80. A cavity 92 is formed by the outer wall. On the side surface of the exhaust pipe 80 facing the cavity 91, a plurality of circular through holes 81 are provided to communicate the space in the exhaust pipe 80 and the space in the cavity 91, and face the cavity 92. A plurality of circular through holes 82 are provided on the side surface of the exhaust pipe 80 to communicate the space in the exhaust pipe 80 and the space in the cavity 92. In the exhaust pipe 80 according to the present embodiment, each of the through holes 81 has the same diameter and each of the through holes 82 has the same diameter, but the diameters of these through holes 81 and 82 are limited to the same diameter. Absent.

  In the silencer 1C according to the present embodiment, cavities 91 and 92 that are partitioned spaces surrounding the exhaust pipe 80 function as a second silencer chamber. That is, the space in the exhaust pipe 80 and the space in the sound deadening chamber (second sound deadening chamber) communicate with each other through the through holes 81 and 82. For this reason, the exhaust pipe 80, the through holes 81 and 82, and the cavities 91 and 92 function as a series of exhaust pipes that guide and discharge the exhaled gas in the trumpet to the space outside the silencer 1C.

  Of the sound waves generated by playing the trumpet, the sound waves entering the exhaust pipe 80 of the silencer 1C pass through the exhaust pipe 80 and are radiated to the space outside the silencer 1C. At this time, the through hole 81 and the cavity 91 function as a Helmholtz resonator that resonates at a frequency determined by the diameter of the through hole 81 and the volume of the cavity 91, and the through hole 82 and the cavity 92 have the diameter of the through hole 82. It functions as a Helmholtz resonator that resonates at a frequency determined by the volume of the cavity 92. For this reason, the sound pressure level of the sound wave passing through the exhaust pipe 80 is attenuated in the vicinity of the Helmholtz resonance frequency due to the through hole 81 and the cavity 91 and the Helmholtz resonance frequency due to the through hole 82 and the cavity 92. Therefore, the volume of the sound emitted to the space outside the silencer 1C is reduced.

  In this embodiment, the same effect as that of the third embodiment is obtained.

<Other embodiments>
Although the first to fourth embodiments of the present invention have been described above, other embodiments are conceivable for the present invention. For example:

(1) In the above embodiments, the trumpet silencers 1 to 1C have been described as examples, but it is needless to say that a similar silencer can be designed for a silencer used for a wind instrument other than the trumpet.

(2) In the first embodiment, one inflatable portion 22 is provided in the exhaust pipe 20. However, the number of expansion portions 22 provided in the exhaust pipe 20 is not limited to one, and a plurality of expansion portions 22 may be provided in the exhaust pipe 20. For example, as in the silencer 1D shown in FIG. 5, the first expansion portion 220 is provided between the upstream portion 210 and the midstream portion 230 of the exhaust pipe 200, and the second between the midstream portion 230 and the downstream portion 250. The inflatable portion 240 may be provided. At this time, the inflating parts 220 and 240 only need to have an inner diameter larger than the inner diameters of the upstream part 210, the midstream part 230, and the downstream part 250, and the inflating part 220 and the inflating part 240 may not have the same dimensions. good. By providing the plurality of expansion parts 220 and 240 in the axial direction of the exhaust pipe 200, the sound is silenced in both of the expansion parts 220 and 240, so that the noise reduction effect is further increased.

(3) In the said 1st Embodiment, the axis | shaft of the exhaust pipe 20 which has the expansion part 22 was linear. However, the exhaust pipe 20 may be bent in the middle of its axis. In the silencer 1E shown in FIG. 6, the axis of the upstream portion 310 of the exhaust pipe 300 is curved by 180 degrees. The curved portion 340 of the exhaust pipe 300 is bent so much that resistance between the exhaled air passing through the upstream portion 310 and the inner wall of the upstream portion 310 does not increase. Then, the exhaled air introduced into the upstream portion 310 from the upstream end 310a of the upstream portion 310 disposed in the vicinity of the inner wall of the bottom portion 12 smoothly passes through the bending portion 340 and is discharged to the space outside the silencer 1E. . Since the breath is guided so as to pass smoothly, the silencing effect can be increased while reducing the feeling of suffocation.

(4) The silencer 1C according to the fourth embodiment is obtained by replacing the silencer 1B according to the third embodiment with a silencer based on Helmholtz resonance. Similarly, the silencer 1 according to the first embodiment may be a silencer based on Helmholtz resonance. FIG. 7 is a longitudinal sectional view showing a configuration of a silencer 1F in which the exhaust pipe 20 of the silencer 1 according to the first embodiment is replaced with an exhaust pipe 400. A cavity 420 is formed by the cylindrical body 430 so as to surround the exhaust pipe in the middle of the exhaust pipe 400 of the silencer 1F. On the side surface of the exhaust pipe 400, a plurality of circular through-holes 410 communicating the space in the exhaust pipe 400 and the space in the cavity 420 are provided. The sound pressure level of the sound wave passing through the exhaust pipe 400 is attenuated in the vicinity of the Helmholtz resonance frequency due to the diameter of the through hole 410 and the volume of the cavity 420. Therefore, the same effects as those of the first embodiment are obtained.

(5) The silencer 1 according to the first embodiment has a hollow casing including the hollow body 11 and the bottom 12 that closes one end of the body 11. However, the silencer housing need not be hollow. This is because the sound is silenced in the muffler chamber if at least the exhaust pipe 20 provided with the muffler chamber is provided. FIG. 8 is a longitudinal sectional view showing the configuration of a silencer 1G according to this modification. The silencer 1G includes an exhaust pipe 20 and a bottom portion 500 that serves as a housing. The exhaust pipe 20 is the same as the exhaust pipe 20 of the silencer 1 according to the first embodiment. The bottom portion 500 has a disk shape, and a mounting portion 520 made of a flexible material is provided on the outer edge of the bottom portion 500. A through hole 510 having the same diameter as the inner diameter of the downstream portion 23 of the exhaust pipe 20 is provided at the center of the bottom portion 500, and the downstream end 23 b of the downstream portion 23 of the exhaust pipe 20 is fixed to the through hole 510 of the bottom portion 500. Has been. The silencer 1G is inserted into the bell 3 from the exhaust pipe 20 side. Then, the attachment portion 520 provided on the outer edge of the bottom portion 500 abuts against the inner wall of the bell 3, whereby the bottom portion 500 is fixed to the inner wall of the bell 3. When the bottom portion 500 is fixed to the bell 3, the silencer 1G closes the bell 3 while leaving the through hole 510 to which the exhaust pipe 20 is fixed. That is, the space inside the bell 3 and the space outside the bell 3 communicate with each other through the exhaust pipe 20 provided with the expansion portion 22 functioning as a sound deadening chamber. For this reason, the energy of the sound wave generated in the bell 3 and entering the expansion portion 22 decreases in the expansion portion 22. Further, in the silencer 1G, when the bottom portion 500 is fixed to the inner wall of the bell 3, a cavity 540 including the inner wall of the bell 3, the inner wall of the bottom portion 500, and the outer wall of the exhaust pipe 20 is formed. This cavity 540 functions as a first silencing chamber. Therefore, the same effect as the silencer 1 according to the first embodiment is obtained.

(6) In the silencers 1B and 1C according to the third and fourth embodiments, as in the silencer 1A according to the second embodiment, the trunk portion 51, the bottom portion 52, and the partition walls that form the cavities 56, 57, 91, and 92 The sound absorbing effect may be increased by providing the sound absorbing material 40 on each of the inner walls 53 and 54.

(7) In the second embodiment, the sound absorbing effect is increased by providing the sound absorbing material 40 on the inner wall of the expanding portion 22. On the other hand, the noise reduction effect may be increased by providing a vibration isolating material on the inner wall or outer wall of the sound deadening chamber such as the expansion portion 22 to suppress vibration or resonance of the sound deadening chamber.

(8) In the third embodiment and the fourth embodiment, two second silencing chambers are arranged outside the first silencing chamber. However, the number of the second silencing chambers is not limited to this, and may be one or a plurality larger than two.

(9) The number of through holes 81 and 82 provided in the exhaust pipe 80 in the fourth embodiment may be one or more.

(10) The minimum inner diameter of the exhaust pipes 20, 60 and 80 in each of the above embodiments is equal to or greater than the minimum inner diameter of the mouthpiece. In order to further improve the feeling of blowing, the minimum inner diameters of these exhaust pipes 20, 60 and 80 may be further increased. At this time, it may be possible to suppress a decrease in the silencing effect by increasing the cross-sectional area and volume of the second silencing chamber.

(11) In the silencers 1 to 1 </ b> C of the above embodiments, the exhaust pipes 20, 60, and 80 are disposed inside the bottom portions 12 and 52. However, the exhaust pipes 20, 60 and 80 may protrude through the through holes 33 and 73 of the bottom portions 12 and 52 to the outside.

(12) In the silencers 1B and 1C of the third and fourth embodiments, the inner wall of the trunk portion 51 is further along the inner wall of the bell 3 in the rear end side direction (inward direction) of the bell 3 than the large-diameter end 51a. The barrel portion 51 may be extended so that the cross-sectional area surrounded by is reduced, and the attachment portion 58 may be provided on the outer wall of the extended barrel portion 51.

  1, 1A, 1B, 1C ... silencer, 3 ... bell, 11, 51 ... trunk, 11a, 51a ... large diameter side end, 11b, 51b ... small diameter side end, 12, 52, 500 ... bottom, 13, 55 , 56, 57, 91, 92, 540 ... cavity, 14, 58, 520 ... mounting part, 20, 60, 80 ... exhaust pipe, 21 ... upstream part, 22 ... expansion part, 23 ... downstream part, 21a, 22a, 23a, 61a, 62a, 63a, 80a ... upstream end, 21b, 22b, 23b, 61b, 62b, 63b, 80b ... downstream end, 31, 32, 33, 71, 72, 73, 81, 82, 510 ... through hole 40, sound absorbing material, 53, 54, partition wall, 61, 62, 63, pipe.

Claims (5)

A housing having a through hole and fixed to the bell of the wind instrument;
Both ends open, one end of which is fixed to the through hole of the housing, and a hollow exhaust pipe that communicates the space inside the bell and the space outside the bell;
It is formed by enlarging the cross-sectional area in the exhaust pipe in the middle of the exhaust pipe, and a muffler chamber communicating with the space in the exhaust pipe;
A muffler characterized by comprising: A housing having a through hole and fixed to the bell of the wind instrument;
Both ends open, one end of which is fixed to the through hole of the housing, and a hollow exhaust pipe that communicates the space inside the bell and the space outside the bell;
A silencing chamber that is a partitioned space surrounding the exhaust pipe,
A silencer having a through hole in a side surface of the exhaust pipe for communicating a space in the exhaust pipe with an inner space of the silencer chamber. The housing is a hollow tube having a front end closed, a rear end opened, and inserted into the bell from the rear end side,
The through hole of the housing is provided in a closing portion that closes the front end of the housing,
The silencer according to claim 1 or 2, wherein the exhaust pipe is accommodated in the casing.   The silencer according to any one of claims 1 to 3, wherein a sound absorbing material is provided on an inner wall of the silencer chamber. The silencer according to any one of claims 1 to 4, wherein an axis of the exhaust pipe is substantially parallel to an axis of the bell when the casing is fixed to the bell.

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