JPH0583797A - External sound introducing device - Google Patents

Abstract

PURPOSE:To remove the resonance to occur between an external sound introducing device tip such as the ear molding and a eardrum and to prevent a user from being annoyed by unpleasantness due to an unnecessary peak by providing a sound adsorbing hole, etc., to adsorb or cancel the sound component of the prescribed frequency at the tip of an ear hole inserting part such as the ear molding. CONSTITUTION:Communication is performed between closed space and back room space 16 by a sound adsorbing hole 14, thus, when discharging is performed through a sound introducing tube 13 into the closed space, the hearing sound reflected by the eardrum is pulled through the sound adsorbing hole 14 into the back room space 16. In this way the sound adsorbing hole 14 or an acoustic damper 17 is drilled or fitted to the ear molding tip, or the ear molding is extended in a drum direction, or two sound paths having the length in which a channel to reach from the earphone to the ear molding tip is dislocated for each half wavelength to the resonance frequency are provided. Thus, the resonance to occur between the ear molding tip and the eardrum is adsorbed, or generated outside the audible range, or can be cancelled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external sound introducing device,
Particularly, when the earphone output is guided to the ear canal of the wearer, the present invention is intended to suppress deterioration of the hearing of the wearer due to a resonance phenomenon generated between the front surface of the ear canal insertion portion and the eardrum of the wearer.

[0002]

2. Description of the Related Art Conventionally, for example, a fitting earplug attached to the tip of the sound path of a hearing aid earphone by a wearer of a hearing aid (formed so as to seal the ear canal in order to guide the sound of the earphone to the ear canal so as not to leak outside). The average distance from the tip of the insertion part of the ear mold inserted into the ear canal to the eardrum of the wearer is about 12.5 [mm] according to JIS C-5512. Therefore, according to the measurement using the JIS standard closed-type artificial ear, the resonance sound component SOX generated in the hearing aid sound based on the resonance generated between the distal end surface of the insertion portion and the eardrum.
Is heard by the wearer (in practice, for example, 20 [Hz] to 8 [kHz]
It is thought that it would be good if the audible range of the above can be heard) has a frequency of around 14 [kHz] that does not seriously affect the audible range. As a result, in the conventional hearing aid, no specific countermeasure was taken against the resonance generated between the distal end surface of the insertion portion and the eardrum.

[0003]

However, according to various experiments, the eardrum is not vertical to the ear canal,
By being inclined with an angle of about 22 °, the average distance from the tip of the insertion portion inserted into the ear canal to the eardrum of the wearer is not always constant depending on the wearer, It has been found that there are cases in which the length may become substantially 20 to 26 mm.

In the case of such a wearer, the conventional 14 [k
The frequency of the resonance sound component generated in the hearing aid sound, which was thought to appear before and after [Hz], is actually generated at a frequency around 7 to 9 [kHz].

The frequencies around 8 [kHz] are values sufficiently included in the audible range of human beings. Therefore, when the hearing aid wearer hears the high-frequency hearing aid, the frequencies around 8 [kHz] are around. It was unavoidable that unpleasant sound (so-called squeaky sound) based on a resonance sound component having a peak at the frequency position was also heard, and the hearing loss was deteriorated.

The present invention has been made in consideration of the above points. With a relatively simple structure, the listening sound generated by the resonance phenomenon between the front surface of the ear hole insertion portion of the external sound introducing device and the eardrum is unnecessary. It is an object of the present invention to propose an external sound introducing device which avoids the occurrence of a peak of a resonance sound component, thereby further improving the hearing of the wearer.

[0007]

In order to solve such a problem, in the first invention, the insertion portion 1 is inserted from the tip of the insertion portion 11 inserted into the ear canal external auditory meatus through the sound passage 13B.
In an external sound introducing device configured to send a listening sound into a closed space 15 sandwiched by 1 and the eardrum 2, a tip portion 11A of the insertion portion 11 facing the eardrum 2 and a position behind the tip portion 11A. And the sound absorbing hole formed so as to penetrate the front end portion 11A.
A back room space 16 communicating with the above is provided.

In the fourth invention, the closed space 4 sandwiched by the insertion portion 40 and the eardrum 2 from the tip of the insertion portion 40 inserted into the ear canal external auditory meatus through the sound passage 43B.
In the external sound introducing device adapted to send the listening sound to 5, the insertion portion 40 is formed so that the distal end portion thereof extends into the external auditory meatus of the bone and does not contact the external auditory meatus wall 8A of the bone.

Further, in the sixth invention, the sound guide tube 63
In the external sound introducing device configured to send the listening sound from the distal end of the insertion portion 60 inserted into the ear canal to the closed space sandwiched by the insertion portion 60 and the eardrum 2, the sound guiding tube 63 Is a plurality of different path lengths L8, L9
Sound paths 63A, 63B, and a plurality of sound paths 63
A and 63B have a path length difference L9-L8 that does not cause unpleasant resonance in the closed space 65.

[0010]

[Function] The back chamber space 1 is provided at the tip of the ear hole insertion portion of the external sound introducing device.
By providing the passage 14 communicating with the valve 6, the resonance sound generated in the closed space 15 can be absorbed. Further, the ear canal insertion portion of the external sound introducing device is extended in the eardrum 2 direction, or a plurality of sound paths 6 having a predetermined path difference L9-L8.
By providing the 3A and 63B, it is possible to prevent the resonance sound which gives the wearer an unpleasant feeling in the closed spaces 45 and 65. As a result, the wearer can obtain an audible sound with less transient and good temporal resolution without being bothered by discomfort due to unnecessary peaks.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings.

(1) First Embodiment In FIG. 1, 11 indicates an ear mold as a whole,
It has a surface adapted to the external auditory meatus of the ear canal, and is composed of a tip portion 11A facing the eardrum 2 and a back portion 11B arranged on the outlet side of the ear canal.
A and the rear portion 11B are spaced apart from each other by the sound guide tube 13
Are connected to each other by. 6 on tip 11A
Individual sound absorbing holes 14 are provided, and the sound absorbing holes 14 are formed so as to penetrate the thickness of the tip portion 11A.

As shown in FIG. 3, the outer shape of the back portion 11B is formed so that the tip end surface when the ear mold 11 is inserted into the ear hole of the wearer is located at a position approximately 20 mm from the eardrum 2. In this wearing state, when the eardrum 2 is viewed from the ear mold 11, the closed space 15 sandwiched between the eardrum 2 and the tip portion 11A, the tip portion 11A, and the tip portion 11A.
And the back chamber spaces 16 sandwiched between the back portions 11B are sequentially arranged, and the sound absorbing hole 1 is provided between the closed space 15 and the back chamber space 16.
4 so that they can communicate with each other.
The hearing aid sound reflected by the eardrum 2 when released through the sound space 3 into the closed space 15 is drawn into the back chamber space 16 through the sound absorbing hole 14.

Here, the acoustic impedance Z _N of the sound absorbing hole 14 when viewed from the closed space 15 toward the back chamber space 16 is given by the following equation:

[Equation 1] Can be represented by

Here, R is the characteristic impedance peculiar to the space, W is the angular frequency of the hearing aid, and B0 is the tip portion 11A.
Thickness, D0 is the diameter of the sound absorbing hole 14, C is the speed of the sound emitted to the closed space 15, that is, the hearing aid sound, and S is the tip portion 11A.
Of the sound absorption holes 14 except the sound path 13B on the wall surface in the eardrum 2 direction
, K is the phase constant of the hearing aid, and L0 is the length of the back room space 16.

Therefore, the acoustic impedance Z _N is expressed by the following equation:

[Equation 2] When the condition that can be expressed as
In particular, when the wavelength of the hearing aid sound is λ, the equation (2) can be transformed by focusing on the frequency f of the hearing aid sound under the condition of L0 <λ / 16.

[Equation 3] The relationship is established. Here, P0 is the opening ratio of the wall surface of the tip of the ear mold 11 facing the eardrum 2, that is, the area of the sound absorbing hole 14 on the wall of the tip of the ear mold 11 is the sound absorbing hole 14 excluding the sound path 13B. The value is divided by the total area included.

The frequency f in the equation (3) is the closed space 1
5 is the frequency at which the acoustic impedance Z _N of the sound absorbing hole 14 becomes the minimum when viewed in the direction of the back room space 16, whereby the sound wave in the closed space 15 that satisfies the frequency of formula (3) absorbs sound. It becomes easy to pass through the hole 14 and enter the back chamber space 16. By the way, in the formula (3), f = 8000 [Hz]
And substituting the sound velocity C = 345000 [mm / sec],

[Equation 4] The relationship is established.

Here, the wavelength λ in the hearing aid sound of frequency 8000 [Hz] is λ = 345000/8000 = 43.25 [mm], and the length L0 of the back chamber space 16 is L0 <λ / 16.
It is necessary to satisfy L0 <43.25 / 16≈2.7 [mm]. However, in the case of this embodiment, L0 = 3 in order to simplify the calculation.
[Mm], and the thickness B0 of the tip portion 11A of the ear mold 11 and the diameter D0 of the sound absorbing hole 14 are B0 = D0 = 1.
The formula (4) is calculated as [mm], and as a result, the porosity P0 becomes P0 = 0.115.

Based on the porosity P0 = 0.115, the diameter of the wall surface of the tip of the ear mold 11 is usually 8 mm, and the diameter of the sound path 13B is 3.2 mm. When the calculation is performed in consideration of the above, a hole having a diameter of 1 [mm] is formed in the tip portion 11A of the ear mold 11 by 6 mm.
It suffices to make individual holes. Therefore, in this embodiment, the thickness B0 of the tip portion 11A of the ear mold 11 is 1
[Mm], the length L0 of the back chamber space 16 is set to a value of 3 [mm], and the tip portion 11A of the ear mold 11 is selected.
There are 6 sound absorbing holes 14 having a diameter of 1 mm.

In the above structure, the hearing aid sound output from the earphone (not shown) passes through the sound path 13B and the acoustic damper 17 inserted at the tip of the sound path 13B.
At this time, the acoustic damper 17 absorbs the resonance sound generated in the sound path 13B. Thus, the hearing aid is emitted into the closed space 15 after passing through the acoustic damper 17. The hearing aid sound emitted into the closed space 15 vibrates the eardrum 2 located in the forward direction of the traveling wave, whereby the hearing aid wearer obtains the hearing aid sound.

At this time, the sound wave reflected by the eardrum 2 travels toward the ear mold 11 and is further reflected by the tip surface of the ear mold 11. As a result, in the closed space 15, resonance occurs at a certain frequency (in this case, 9 [kHz]) as shown by the characteristic curve S0 in FIG. Of this resonance sound, the resonance component whose frequency is around 8000 [Hz] is 80
Closed space 15 and back room space 16 at a frequency of 00 [Hz]
The tip 11 so that the acoustic impedance of the
Since the dimension values of A and the back chamber space 16 and the dimension values of the six sound absorbing holes 14 that connect the closed space 15 and the back chamber space 16 are selected, the back chamber space passes through the sound absorbing holes 14. Absorbed in 16.

Therefore, the frequency from the inside of the closed space 15 is 8000 [Hz].
The front and rear resonance sound components can be removed, thereby eliminating the resonance phenomenon occurring near this frequency. According to the above configuration, the sound absorbing hole 14 is formed in the tip portion 11A of the ear mold 11, and the back chamber space 16 is provided behind the sound absorbing hole 14, so that the characteristic curve S1 shown in FIG. , It is possible to suppress the peak of the resonance sound around the frequency of 8000 [Hz] generated in the closed space 15, and thereby the time resolution with a small transient can be obtained without being bothered by the undesired peaks over the entire frequency range. It may provide a good hearing aid to the hearing aid wearer.

(2) Second Embodiment FIGS. 5, 6 and 7 show a second embodiment in which the ear mold 20 has a sound guide tube 23 similar to that shown in FIG.
The end surface of the ear mold 20 on the eardrum 2 side is almost 20 from the eardrum 2.
It is inserted to a position of [mm], and thus a closed space 25 is formed between the eardrum 2 and the ear mold 20.

In addition to this structure, the ear mold 20 is provided with six sound absorbing holes 21. The sound absorbing hole 21 is formed from the tip of the ear mold 20 on the eardrum 2 side toward the outside of the ear canal, so that the sound absorbing hole 21 communicates with the closed space 25 and is a hole having a circular cross section whose tip is closed. I am configuring. Here, the acoustic impedance Z _M seen from the open end side of the sound absorbing hole 21, that is, the closed end direction of the sound absorbing hole 21 from the direction of the eardrum 2 is as follows:

[Equation 5] It is expressed as.

Here, C is the speed of the hearing aid, λ is the wavelength of the hearing aid, and L1 is the length of the sound absorbing hole 21. Therefore, in the formula (5), the length L1 of the sound absorbing hole 21 is

[Equation 6] When the condition of is satisfied, that is, the length L1 of the sound absorbing hole 21
, L1 = (C / 4f) · N (N is an integer), the acoustic impedance Z _M near the open end of the sound absorbing hole 21 becomes substantially zero.

As a result, among the sound components propagating in the closed space 25, only the sound components satisfying the condition enter the sound absorbing hole 21 and are absorbed. In this example, a frequency of 8000
Considering that the wavelength λ at [Hz] is about 40 mm, the length L1 of the sound absorbing hole 21 is 10 mm when N = 1 in the equation (6). Therefore, the tip of the ear mold 20 has a diameter of 1.2 [mm] and a length L1 = 10 [m.
Six sound absorbing holes 21 of m] are formed.

In the above structure, the hearing aid sound emitted from the earphone (not shown) passes through the acoustic damper 27 fitted in the tip of the sound guide tube 23, and the resonance component generated in the sound guide tube 23 is generated. After being suppressed, it is fed into the closed space 25.
The hearing aid sent into the closed space 25 travels in the closed space 25 in the eardrum 2 direction, vibrates the eardrum 2, and then becomes a reflected wave to travel in the ear mold 20 direction.

Of the waves reflected by the eardrum 2, the frequency 8000
Sound components around [Hz] are absorbed by the sound absorption holes 21 having a length L1 selected to absorb sound waves of 8000 [Hz]. Therefore, the frequency is 8000 [Hz] from within the closed space 25.
Surrounding sound components can be removed, thereby eliminating resonances that occur near this frequency.

According to the above construction, the sound absorbing hole 21 formed at the tip of the ear mold 20 removes only the reflected wave around the frequency of 8000 [Hz], so that the characteristic curve S of FIG.
As shown in FIG. 2, it is possible to reduce the peak of the sound component around the frequency 8000 [Hz] among the sound components propagating in the closed space 25, and thus it is possible to effectively suppress the resonance of the sound component. As a result, it is possible to provide a hearing aid wearer with a hearing aid sound with less transient and good time resolution without being bothered by discomfort due to unnecessary peaks over the entire frequency range.

(3) Third Embodiment FIGS. 8 and 9 show a third embodiment. The ear mold 30 has a sound guide tube 33 similar to that shown in FIG. 1, and the ear mold 30 is inserted into the ear hole. In this state, a closed space 35 is formed between the eardrum 2 and the ear mold 30. Here, the length L2 of the closed space 35, that is, the eardrum 2 and the ear mold 3
0 The distance between the tip surfaces is inevitably different because the length of the ear canal is different for each wearer.

In addition to the above-mentioned structure, a sound absorbing hole 31 having a diameter larger than that of the sound guiding tube 33 is formed at the tip of the ear mold 30 so as to surround the sound guiding tube 33. The sound absorbing hole 31 is formed so as to be substantially parallel to the sound guide tube 33, and the depth from the tip of the ear mold 30 is L3. A spacer 32 made of, for example, a plastic material is fitted into the closed end of the sound absorbing hole 31, and the spacer 3
The length L4 of 2 is, for each hearing aid wearer, the structure of the wearer's ear,
It can be selected to fit the size.

In the case of this embodiment, the length L3 of the sound absorbing hole 31 into which the spacer 32 is not inserted is selected to be 13.5 [mm], and the length L2 of the spacer 32 is 0 [mm] to 4.5.
It is designed to be adjustable in the range of [mm]. Therefore, the substantial depth L5 of the sound absorbing hole 31 with the spacer 32 inserted in the sound absorbing hole 31 is 9 [mm].
It becomes a range of up to 13.5 [mm], and when this value is substituted into the equation (6) and calculation is performed with N = 1, the sound absorbing hole 31 is adjusted by adjusting the length L4 of the spacer 32 within the above range. It can absorb sound waves in the frequency range of 6400 [Hz] to 9600 [Hz].

In the above structure, the hearing aid sound sent into the closed space 35 through the sound guiding tube 33 has different lengths L2 of the closed space 35 for each wearer, so that each wearer in the closed space 35 has a different length L2. It causes resonance of different frequencies. Here, for example, in the closed space 35, a frequency of 9000 [Hz]
When the resonance occurs, the length L4 of the spacer 32 is set to about 4 [mm] in consideration of the expression (6), and the substantial depth L5 of the sound absorbing hole 31 is set to about 9.5 [mm]. Further, when resonance of a frequency of 7000 [Hz] occurs, the length of the spacer L4 is set to about 1.2 [mm] in the same manner so that the substantial depth L5 of the sound absorbing hole 31 is 12.3 [mm].
Set to.

At this time, the acoustic impedance in the direction of the sound absorbing hole 31 for 9000 [Hz] and 7000 [Hz] becomes almost zero, and thus the frequency 9000 [Hz] and the frequency generated in the closed space 35
The sound component of 7000 [Hz] is absorbed by the sound absorbing hole 31. According to the above structure, the spacer 32 having a variable length is provided in the sound absorbing hole 31 formed at the tip of the ear mold 30.
By inserting the sound absorbing hole 31, the substantial length L
5 can be made variable.

As a result, the depth L5 of the sound absorption hole 31 can be selected so as to be tuned to a predetermined resonance frequency for each hearing aid wearer, and the adaptability to the ear hole structure of the wearer can be further enhanced. .. In this way, it is possible to eliminate the unpleasant sound due to resonance that is felt at different frequencies for each hearing aid user, and there is no transient discomfort over the entire frequency range. Can be provided to the hearing aid wearer.

(4) Fourth Embodiment FIG. 10 shows the fourth embodiment and shows the relationship between the ear mold 40 inserted into the ear hole and the ear hole around the ear mold 40. The ear mold 40 is the cartilage external auditory meatus wall 8B.
The ear mold 40 is located at the back of the cartilage external auditory meatus so as to reach the bone external auditory canal formed by the bone external auditory canal wall 8A. Has been done. Further, the tip part of the ear mold 40 is formed so as to become thinner from the end point of the cartilage outer ear canal toward the eardrum 2 side so as to be separated from the inner wall of the cartilage ear canal. Is designed not to cause pain caused by touching the external auditory meatus wall 8A of the bone part.

In the case of this embodiment, the ear mold 40 extended so as to project into the external auditory meatus of the bone part is projected from the wall surface of the external auditory meatus as compared with the conventional ear mold 1 as shown in FIG. The length of the tip part to be used is selected to be about 7.5 [mm], and thus the distance L6 from the tip of the ear mold 40 to the eardrum 2 is the same as that of the standard closed type pseudo ear defined by JIS C-5512. It will be about 12.5 [mm]. Earphone (not shown) having the above configuration
The hearing aid emitted from the sound guiding tube 43 is sent into the closed space 45 after suppressing the resonance generated in the sound guiding tube 43 by the acoustic damper 47 fitted in the tip end portion of the sound guiding tube 43, and the eardrum 2 direction. Proceed to.

Here, from the tip of the ear mold 40 to the eardrum 2
The distance L6 to the ear mold 40 and the eardrum 2 is set to about 12.5 [mm], which is the same as that of the standard closed type pseudo ear defined by JIS C-5512.
In the meantime, a resonance around a frequency of 14 [kHz], which is significantly higher than that of a sound component around a frequency of 8 [kHz] generated between the ear mold 1 and the eardrum 2 as shown in FIG. 18, is generated. The resonance around the frequency of 14 [kHz] has almost no effect on the hearing of the wearer. Therefore, the wearer can hear the hearing aid sound without the uncomfortable region due to the resonance.

According to the above configuration, the ear canal 40 is formed in the closed space 45 by extending the ear canal insertion portion so as to reach the inside of the bone ear canal as compared with the conventional case. In practice, the peak of the resonance sound component can be generated at a frequency higher than the audible frequency of the wearer, and as a result, a hearing aid that can improve the hearing so that the resonance sound generated in the closed space 45 cannot be heard can be realized.

(5) Fifth Embodiment FIGS. 11 to 13 show a fifth embodiment. The ear mold 50 has the same sound guide tube 53 as in FIG. 1, and the sound guide tube 53 side of the eardrum 2 is located. The tip is inserted from the eardrum 2 to a position of about 20 [mm], and a closed space 55 is formed between the eardrum 2 and the ear mold 50.

In addition to these constitutions, the ear mold 50
The acoustic damper 51 is attached to the tip of the eardrum 2 in the direction toward the eardrum 2.
Is installed. The acoustic damper 51 has a truncated cone shape and is made of a porous sound-absorbing material having a sponge shape of closed cells, and thus has an acoustic impedance capable of absorbing a sound component particularly in a high frequency range, and also has an ear canal wall. It is designed to become thinner as it goes to the tip so that it does not come into contact with 8.

This embodiment is constructed on the basis of the preliminary experiment of FIG. 12, and the sound pressure distribution data obtained as shown in FIG. 12 (B) from the experimental apparatus shown as a sectional view in FIG. 12 (A). Based on the above, the particle velocity distribution as shown in FIG. 12 (C) was predicted. The experimental apparatus shown in FIG. 12 (A) is configured to imitate a state in which an ear mold is inserted into the ear canal and has a closed space 55 surrounded by wall surfaces.
The sound pressure distribution in the closed space 55A can be examined by sending a sound wave from A to the sound path 53C provided at the right side wall position.

In the case of this experiment, the length L8 of the closed space 55A
Is selected as 34.5 [mm], and the sound pressure distribution generated in the closed space 55A when a sound wave having a frequency of 10 [kHz] is sent into the closed space 55A from the sound path 53C on the right side wall toward the left side wall is investigated. I did it. According to the particle velocity distribution (FIG. 12 (C)) expected from the sound pressure distribution data (FIG. 12 (B)) obtained by the above device, the peak of the particle velocity due to the sound wave having the frequency of 10 [kHz] is obtained. 8.6 each from the left side wall
It can be seen that it occurs near [mm] and 25.8 [mm].

As a result, the experimental apparatus (FIG. 12 (A))
In the closed space 55A, by providing a truncated cone-shaped acoustic damper 51A whose bottom surface is in close contact with the right side wall and whose top surface is located 25.8 [mm] away from the left side wall,
A sound wave having a frequency of 10 [kHz] generated in the closed space 55A can be efficiently absorbed.

Accordingly, in FIGS. 13 (A) and 13 (B) showing the structure and the particle velocity distribution in the closed space 55 when the ear mold 50 is inserted into the actual ear hole, the eardrum 2 is seen from the tip of the ear mold 50. As shown in FIG. 13 (B), the particle velocities of the resonance sound components around the frequency 8 [kHz] generated in the closed space 55 having a distance of 20 [mm] are as shown in FIG. At zero, and becomes maximum at a position near 10 [mm] from the eardrum 2 corresponding to the midpoint of the closed space 55. As a result, the length L7 of the acoustic damper 51 provided so that the bottom surface of the truncated cone shape is in close contact with the tip surface of the ear mold 50 and the top surface extends in the eardrum 2 direction is selected to be L7 = 10 [mm]. This allows the maximum particle velocity to be canceled out, which also maximizes the absorption efficiency.

However, in the case of this embodiment, the length L7 of the acoustic damper 51 is 7 [mm] in consideration of the contact between the acoustic damper 51 and the external auditory meatus wall 8A of the bone which is a very sensitive portion.
Has been done to a degree. With the above structure, the hearing aid sound emitted from the earphone (not shown) of the hearing aid is guided by the sound guide tube 53.
Is fed into the closed space 55 through.

Of the hearing aid sound sent into the closed space 55, the resonance component around the frequency 8 [kHz] generated in the closed space 55 has a structure for absorbing the sound component around the frequency 8 [kHz]. , Can be suppressed by the acoustic damper 51 having the length L7 that effectively cancels the particle velocity of the sound wave having the frequency of 8 [kHz].

According to the above configuration, the characteristic curve S of FIG.
As shown in Fig. 3, the frequency 8 [kHz generated in the closed space 55
z) It is possible to suppress the peaks of the sound components before and after, thereby providing the hearing aid wearer with a hearing aid sound with little transient and good time resolution without being bothered by discomfort due to unnecessary peaks over the entire frequency range. obtain.

(6) Sixth Embodiment FIG. 15 shows a sixth embodiment, in which two sound guide tubes 63 are provided for sending the hearing aid sound emitted from the earphone (not shown) of the hearing aid into the ear canal. It is composed of 63A and 63B. The sound path 63A and the sound path 63B have paths of different lengths, respectively, whereby the hearing aid sent from the earphone (not shown) into the sound guide tube 63 passes through the sound path 63A and the sound path 63B. At this time, at a tip position of the ear mold 60, it is sent out into the closed space 65 from different outlets with a predetermined time difference corresponding to the difference in length.

Here, the sound path 63B has a longer path length than the sound path 63A, so that the time difference T1 when the hearing aid is sent from the sound paths 63A and 63B to the closed space 65 at the tip position of the ear mold 60 is reduced. , The following equation,

[Equation 7] It is expressed as. Here, L8 represents the path length of the sound path 63A, L9 represents the path length of the sound path 63B, and C represents the speed of sound.

The path length L8 of the sound path 63A and the sound path 63
The path length L9 of B is

[Equation 8] Are selected so that Here, λ represents the wavelength of the hearing aid. In the case of this embodiment, the frequency 8000 (H
z], that is, eq. (8) is applied to a sound wave of λ = 345000 / 8000≈43 [mm], and n = 0 is selected in consideration of making the sound guide tube 63 portion as small as possible. ..

At this time, according to the equation (8), the path length difference L9-L8 between the sound path 63B and the sound path 63A is set to about 20 [mm], whereby the sound wave of about 8 [kHz] of the hearing aid sound is generated. When emitted from the sound paths 63A and 63B into the closed space 65, they are shifted by a half wavelength. In the above configuration, the hearing aid sound emitted from the earphone (not shown) of the hearing aid passes through the different sound paths 63A and 63B when propagating in the sound guide tube 63, and then from different outlets in the closed space 65. Sent to.

Here, due to the difference in the length of the sound path 63A and the sound path 63B, the hearing aid sound propagating in the sound path 63B is the sound path 6.
It is sent into the closed space 65 with a delay of half a wavelength as compared with the hearing aid sound propagating through 3A. As a result, the frequency of the hearing aid sound that has passed through the sound paths 63A and 63B is 8 [kHz
The main components before and after z] cancel each other out in the closed space 65. As a result, as shown by the characteristic curve S4 in FIG. 16, the resonance of the sound component can be suppressed.

According to the above-mentioned configuration, the hearing aid sound component in the sound guiding tube 63 before entering the closed space 65 composed of the distal end surface of the ear mold 60, the eardrum 2 and the ear canal wall 8 is related to the sound component of the frequency to be removed. By providing a path length difference of half a wavelength, unnecessary resonance sound can be suppressed from within the closed space 65, whereby the hearing aid wearer does not suffer from discomfort due to unnecessary peaks and has a short transient time. A hearing aid with good resolution can be obtained.

(7) Other Embodiments In the first embodiment described above with reference to FIGS. 1 to 4, six cylindrical sound absorbing holes 14 are formed so as to surround the sound guide tube 13. The present invention is not limited to this, and as a sound absorbing hole, for example, as shown in FIG. 17, a notch 74 for communicating the closed space and the back chamber space 76 may be provided in the peripheral portion of the tip portion 71A of the ear mold 70. The point is that various shapes and numbers of sound absorbing holes having the aperture ratio P0 satisfying the relationship of the expression (3) may be provided.

In the second embodiment described above with reference to FIGS. 5 to 7, six sound absorbing holes 21 having a diameter of 1.2 [mm] are provided, but the shape and the number thereof are not limited to this. Even if the sound absorbing holes of various shapes and numbers are changed, the same effect as the above case can be obtained.

Further, the third described above with reference to FIGS. 8 and 9.
In the embodiment, the sound guiding tube 33 is wrapped around the sound absorbing hole 31 and the spacer 32 is fitted therein. However, the present invention is not limited to this, and a plurality of sound absorbing holes are provided. At the same time, a spacer may be fitted into each of them. Further, in the above-described third embodiment, the case where the spacer 32 is fitted and inserted up to the closed end side of the sound absorbing hole 31 has been described, but the present invention is not limited to this, and a spacer movable in the sound absorbing hole 31 is used. By applying it, even if the substantial depth L5 of the sound absorbing hole 31 can be adjusted, the same effect as the above case can be obtained.

Furthermore, in the fifth embodiment described above with reference to FIGS. 11, 13 and 14, the acoustic damper 51 protruding toward the eardrum 2 is attached to the tip of the ear mold 50, but the present invention is not limited to this. No, the ear mold 50
Even if the material itself is made of a sound absorbing material, the same effect as the above case can be obtained. Furthermore, in the above-described first to sixth embodiments, the ear mold having the sound generation source outside the ear hole insertion portion has been described, but the present invention is not limited to this, and the sound generation is performed, for example, as in an ear type hearing aid. It can also be applied to an ear mold that is integrated with the source and inserted into the ear hole.

Furthermore, in the above-mentioned first to sixth embodiments, the ear mold of the hearing aid is described in particular, but the present invention is not limited to this, and an external sound introducing device may be used to transmit sound waves emitted by various other audio equipment. It can also be widely applied to those adapted to be fed into the ear canal.

[0060]

As described above, according to the present invention, a sound absorbing hole or a sound absorbing hole for absorbing or canceling a sound component of a predetermined frequency at the tip of the ear hole insertion portion of the ear mold, or an acoustic damper or a plurality of sound absorbing holes. By providing a sound path, etc., it is possible to suppress the resonance sound that occurs in the high frequency range, and this allows the wearer to hear with less transient and good temporal resolution, without the discomfort of unnecessary peaks. Can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of a first embodiment of an ear mold according to the present invention.

FIG. 2 is a front view showing the ear mold tip portions of the first and second embodiments.

FIG. 3 is a cross-sectional view showing a state in which the ear mold is inserted in the ear mold of the first embodiment as a cross section taken along the line AA in FIG.

FIG. 4 is a graph showing sound pressure levels with respect to frequency in the first example and the conventional example.

FIG. 5 is a perspective view showing the overall structure of an ear mold according to a second embodiment.

FIG. 6 is a cross-sectional view showing a state in which the ear mold is inserted in the ear mold of the second embodiment as a cross section taken along the line AA in FIG.

FIG. 7 is a graph showing sound pressure levels with respect to frequency in the second example and the conventional example.

FIG. 8 is a perspective view showing the overall structure of an ear mold of a third embodiment.

FIG. 9 is a cross-sectional view showing an ear hole insertion state of an ear mold of a third embodiment as a cross section including a center axis of the ear mold.

FIG. 10 is a cross-sectional view showing the ear mold insertion state of the ear mold of the fourth embodiment as a cross section including the center axes of the ear mold and the ear canal external auditory meatus.

FIG. 11 is a perspective view showing the overall structure of an ear mold according to a fifth embodiment.

FIG. 12 is a graph showing a preliminary experimental device and experimental results relating to the fifth example.

FIG. 13 is a correlation diagram showing the relationship between the position occupied by the acoustic damper in the ear canal and the particle velocity in the fifth embodiment.

FIG. 14 is a graph showing the sound pressure level with respect to frequency in the fifth example and the conventional example.

FIG. 15 is a schematic cross-sectional view showing a sound guide tube and an ear mold of a sixth embodiment.

FIG. 16 is a graph showing the sound pressure level with respect to frequency in the sixth example and the conventional example.

FIG. 17 is a perspective view showing the overall configuration of another embodiment.

FIG. 18 is a cross-sectional view of a conventional ear mold when an ear hole is inserted.

FIG. 19 is a graph showing the sound pressure level with respect to frequency by the conventional standard closed type artificial ear.

[Explanation of symbols]

1, 10, 20, 30, 40, 50, 60, 70 ... Ear mold, 11A ... Ear mold tip portion, 11B
The rear part of the ear mold, 3, 13, 23, 33, 4
3, 53, 63, 73 ... Sound guide tube, 3B, 13B, 23
B, 33B, 43B, 53B, 63A, 63B ... sound path, 14 ... sound absorbing hole, 16 ... back room space, 7, 17,
27, 37, 47, 57, 67, 77 ... Acoustic damper,
21, 31 ... Sound absorption holes, 32 ... Spacers, 51 ...
Acoustic damper, S0 ... Conventional characteristic curve, S1-S4 ...
The characteristic curve in an Example.

Claims (6)

[Claims] 1. An external sound introducing device adapted to send a listening sound from a tip of an insertion portion inserted into an ear canal external auditory meatus into a closed space sandwiched by the insertion portion and an eardrum through a sound passage, A back chamber space that communicates with the closed space through a tip portion of the insertion portion that faces the eardrum and a sound absorbing hole that is formed at a position behind the tip portion and that penetrates the tip portion. An external sound introducing device characterized by comprising: 2. An external sound introducing device adapted to send a listening sound from the tip of an insertion portion inserted into the external auditory meatus of the ear canal into a closed space sandwiched by the insertion portion and the eardrum through the sound passage. The external sound introducing device, wherein the insertion portion is provided with a sound absorbing hole having a predetermined depth from the closed space toward the ear hole exit direction. 3. The depth of the sound absorbing hole is made variable by inserting a spacer having a shape that fills a predetermined section of the sound absorbing hole into the sound absorbing hole. The external sound introducing device according to claim 2, which is characterized in that. 4. An external sound introducing device configured to send a listening sound from a tip of an insertion portion inserted into an ear canal external auditory meatus to a closed space sandwiched by the insertion portion and the eardrum through the sound passage. The external sound introducing device according to claim 1, wherein a tip portion of the insertion portion is formed so as to extend into the external auditory meatus of the bone and not contact the external auditory meatus wall of the bone. 5. An external sound introducing device adapted to send a listening sound from a tip of an insertion portion inserted into an ear canal external auditory meatus into a closed space sandwiched by the insertion portion and an eardrum through a sound passage. An external sound introducing device, wherein a sound absorbing material capable of absorbing a sound component of a resonance frequency is attached to a tip of the insertion portion on the eardrum side. 6. An external sound introducing device adapted to send a listening sound from a tip of an insertion portion inserted into an ear canal external auditory meatus into a closed space sandwiched by the insertion portion and the eardrum through a sound guide tube. The sound guide tube has a sound path having a plurality of different path lengths, and the plurality of sound paths have a path length difference such that unpleasant resonance does not occur in the closed space. An external sound introducing device characterized in that