JPWO2020121936A1 - Earplug - Google Patents

Abstract

Earplugs (51) have a first inner diameter (da1) air chamber (121) with one end open and a first inner diameter (da2) smaller than the first inner diameter (da1). A duct portion (122) having a through hole (122a) and protruding from the other end of the air chamber portion (121), a main body portion (1) having a through hole (122a) and being attachable to the ear canal (Ea), and a first. An adjustment that has a second through hole (23) with a third inner diameter (da3) smaller than the inner diameter (da1) and is movably mounted in the air chamber portion (121) of the main body portion (1). It has a part (2) and.

Description

The present disclosure relates to earplugs.

Patent Document 1 describes earplugs having a sound path. The sound path passage is provided with a plurality of expansion spaces for expanding the passage area.

Japanese Unexamined Patent Publication No. 6-343659

Earplugs have a variety of uses, and the frequency characteristics desired of earplugs with respect to sound pressure reduction vary depending on the use. For example, in a loud concert venue, frequency characteristics that reduce the volume of the entire frequency band of audible sound are required, and in a loud environment such as a construction site, sound in a band other than human voice is relatively required. Frequency characteristics that reduce pressure are desired. The earplugs described in Patent Document 1 are difficult to use for various purposes because the frequency characteristics after the sound pressure is reduced are fixed.

An embodiment is to provide earplugs that can be used in a variety of applications.

According to one aspect of the embodiment, the air chamber has a first inner diameter air chamber portion with one end open and a first through hole having a second inner diameter smaller than the first inner diameter. The main body has a duct portion protruding from the other end of the portion and can be attached to the ear canal, and has a second through hole having a third inner diameter smaller than the second inner diameter. Provided is an earplug provided with an adjusting portion that is attached to the air chamber portion so as to be movable in the axial direction from the side of the one end portion.

According to the embodiment, the effect that it can be used for various purposes can be obtained.

FIG. 1 is a perspective view showing the appearance of earplugs according to the embodiment. FIG. 2 is a cross-sectional view for explaining the configuration of earplugs. 3A and 3B are cross-sectional views for explaining a first adjusted state of earplugs, FIG. 3A is a view showing a state in which the earplugs in the first adjusted state are inserted into the ear canal Ea, and FIG. 3B is a first view. It is a model diagram of the ventilation path in the adjusted state. 4A and 4B are cross-sectional views for explaining a second adjusted state of the earplugs, FIG. 4A is a view showing a state in which the earplugs in the second adjusted state are inserted into the ear canal Ea, and FIG. 4B is a second view. It is a model diagram of the ventilation path in the adjusted state. FIG. 5 is a graph of frequency characteristics for explaining the sound pressure reducing action of earplugs. FIG. 6 is an enlarged view of part A in FIG. FIG. 7 is a cross-sectional view for explaining the earplugs according to the modified example.

The earplugs according to the embodiment of the present disclosure will be described. FIG. 1 is a perspective view showing the appearance of the earplugs 51 according to the present embodiment. The earplug 51 has a main body portion 1 and an adjusting portion 2 attached (inserted) to the main body portion 1. FIG. 2 is a cross-sectional view for explaining the configuration of the earplugs 51, and is an assembly view showing a state before the adjusting portion 2 is screwed into the main body portion 1.

As shown in FIGS. 1 and 2, the main body 1 has a base 12 and a cushion 11. The base portion 12 has a cylindrical air chamber portion 121 having one end open, and a tubular duct portion 122 extending from the other end of the air chamber portion 121 on its axis. The inner peripheral surface of the air chamber portion 121 has a female screw portion 121a on which a female screw is formed. The duct portion 122 has a through hole 122a in which one end side communicates with the internal space of the air chamber portion 121 and the other end portion communicates with the external space Vg. The inner diameter of the air chamber portion 121 is defined as the inner diameter (first inner diameter) da1. In this example, the inner diameter of the female screw portion 121a is the inner diameter da1. The inner diameter (second inner diameter) da2 of the through hole 122a is set smaller than the inner diameter da1 of the air chamber portion 121.

The base 12 is made of resin or metal. The resin is, for example, PC (polycarbonate). The metal is, for example, aluminum.

The cushion portion 11 has, for example, a substantially columnar outer shape extending in the axial direction. The cushion portion 11 is made of a flexible material. The material is, for example, a sponge made of chloroprene rubber or the like, or a thermoplastic elastomer. When the cushion portion 11 is formed of a sponge, the cushion portion 11 is fitted and integrated with the base portion 12. When the cushion portion 11 is formed of a thermoplastic elastomer, it is formed by integral molding with the base portion 12 as a resin.

As shown in FIGS. 1 and 2, the adjusting portion 2 has a disc-shaped knob portion 21 and a columnar screw portion 22 protruding from the knob portion 21 on its axis. The adjusting portion 2 is made of resin or metal. The resin is, for example, PC (polycarbonate). The metal is, for example, aluminum. The picking portion 21 is a portion to be picked by a finger, and a knurl 21a for preventing slip is formed on the outer peripheral surface. The threaded portion 22 has a male threaded portion 221. A thread forming a male screw is formed on the outer peripheral surface of the male screw portion 221. Therefore, the male screw portion 221 can be screwed into the female screw portion 121a of the base portion 12 in the main body portion 1. The adjusting unit 2 has through holes 23 penetrating both ends on the axis. In other words, the adjusting unit 2 has a through hole 23 that penetrates the adjusting unit 2 in the axial direction. The inner diameter (third inner diameter) da3 of the through hole 23 is set smaller than the inner diameter da1 of the air chamber portion 121. The inner diameter da3 of the through hole 23 is set to a value closer to the inner diameter da2 of the through hole 122a in the duct portion 122 than the inner diameter da1 of the air chamber portion 121. For example, the inner diameter da3 is the same as the inner diameter da2.

The adjusting portion 2 is screwed (mounted) to the air chamber portion 121 of the base portion 12 of the main body portion 1 in the direction indicated by the arrow DRa in FIG. FIG. 1 shows a state in which the male screw portion 221 of the adjusting portion 2 is screwed halfway with respect to the female screw portion 121a of the main body portion 1.

When the adjusting portion 2 screwed into the main body 1 is screwed, the tip surface 22a of the screwed portion 22 comes into contact with the bottom surface 121b of the air chamber 121 of the main body 1. This contact regulates the screwing of the adjusting unit 2.

The state of the earplugs 51 in which the front end surface 22a is in contact with the bottom surface 121b and the adjusting portion 2 has entered the deepest position is referred to as a first adjustment state. FIG. 3A shows a state in which the earplug 51 in the first adjusted state is inserted (mounted) into the ear canal Ea. In the first adjustment state, the cushion portion 11 comes into close contact with the inner wall of the ear canal Ea and seals (closes) the ear canal Ea. Further, the through hole 23 of the adjusting portion 2 and the through hole 122a in the duct portion 122 of the main body portion 1 are concentrically directly communicated (connected), and the air chamber R (see FIG. 4) is not formed. The ventilation path D that communicates the external space Vg and the internal space Ve of the ear canal Ea is substantially only one linear ventilation path DA.

FIG. 3B is a model diagram showing the ventilation path D in the first adjusted state as the ventilation path model MA. The through hole 122a is referred to as a duct D2, and the through hole 23 is referred to as a duct D3. In the first adjusted state, the air passage DA has a duct D1 that connects the duct D2 and the duct D3. That is, the earplugs 51 can be considered to have a ventilation path DA composed of one duct D1 in the first adjusted state. Here, the inner diameter da2 of the through hole 122a and the inner diameter da3 of the through hole 23 are both represented by the same inner diameter da. Further, the length of the through hole 122a is defined as the length L2, the length of the through hole 23 is defined as the length L3, the volume of the internal space of the through hole 122a is defined as the volume V2, and the volume of the internal space of the through hole 23 is defined as the volume V3. .. Further, the sum of the length L2 and the length L3 is defined as the length LA, and the sum of the volume V2 and the volume V3 is defined as the volume VA. Therefore, in the vent model MA, the vent D shown in FIG. 3 is represented as a vent DA having an inner diameter da, a length LA (L), and a volume VA.

The state of the earplug 51 in which the adjusting portion 2 is screwed back (retracted) from the first adjusting state to form the air chamber R inside the air chamber portion 121 is referred to as the second adjusting state. That is, in the second adjustment state, the tip surface 22a of the adjustment unit 2 does not abut on the bottom surface 121b of the air chamber portion 121. FIG. 4A shows a state in which the earplug 51 in the second adjusted state is inserted (attached) into the ear canal Ea. In the second adjustment state, an air chamber R as a columnar space is formed between the through hole 122a of the duct portion 122 and the through hole 23 of the adjustment portion 2. The inner diameter of the air chamber R is larger than the inner diameter of the through hole 23 and the through hole 122a. FIG. 4B is a model diagram showing the ventilation path D in the second adjusted state as a ventilation path model MB. As described above, the air passage D in the second adjusted state includes the air chamber R formed between the duct D2 and the duct D3. That is, in the second adjusted state, the earplugs 51 can be regarded as having an air passage DB formed by interposing the air chamber R in the intermediate portion of the air passage DA in the first adjusted state.

The vent DB has a length LB and a volume VB. Here, assuming that the axial length of the air chamber R is the length LR and the volume of the air chamber R is the volume VR, the length LB is the sum of the length LA and the length LR, and the volume VB is It is the sum of the volume VA and the volume VR.

The earplugs 51 may be provided with a movement restricting unit (not shown). The movement regulation unit regulates the maximum distance (movable distance) at which the adjustment unit 2 can be screwed (backward) from the first adjustment state to a predetermined value. In this case, the state in which the adjusting unit 2 is located at the position regulated by the movement restricting unit is referred to as the maximum adjusting state. The air passage DB including the air chamber R becomes the air passage Dmax having the maximum length L2max and the maximum volume VBmax in the maximum adjusted state.

That is, the earplugs 51 move the adjusting unit 2 forward and backward so that the ventilation path D has an arbitrary length from the ventilation path DA corresponding to the first adjustment state to the ventilation path Dmax corresponding to the maximum adjustment state ( And the volume corresponding to the length) can be adjusted as a ventilation path DB.

The through hole 122a of the main body 1 is one end of the ventilation path D, and the through hole 23 of the adjustment portion 2 is the other end of the ventilation path D. With the cushion portion 11 inserted into the external auditory canal Ea, the through hole 122a of the main body portion 1 communicates with the internal space Ve of the external auditory canal Ea, and the through hole 23 of the adjusting portion 2 communicates with the external space Vg. Therefore, the ventilation path D communicates between the external space Vg and the internal space Ve of the external auditory canal Ea, and functions as an acoustic filter of sound transmitted from the external space Vg into the external auditory canal Ea. On the other hand, the earplugs 51 can adjust the volume VR of the air chamber R of the air passage D as an acoustic filter and the length LR linked to the volume VR by adjusting the axial position of the adjusting unit 2 with respect to the main body 1. Therefore, the user wearing the earplugs 51 can hear the attenuated external sound based on the frequency characteristic according to the adjustment position of the adjustment unit 2.

In the ventilation passage D, the through hole 23 serves as an inlet for external sound, and the through hole 122a serves as an outlet for external sound. Since the inner diameter da2 of the through hole 122a is sufficiently smaller than the inner diameter of the ear canal Ea, the sound pressure is reduced in a wide range in the audible frequency band. Further, by adjusting the axial position of the adjusting unit 2 with respect to the main body portion 1, the volume VR and the length LR of the air chamber R corresponding to the position can be changed, and the characteristics of the reduced audible frequency band can be changed.

FIG. 5 is a graph showing the characteristics of the earplugs 51 as an acoustic filter. This property is obtained as follows. First, a model ear canal is created as a model corresponding to the ear canal Ea, and a microphone is installed in the model ear canal. Further, the speaker is arranged at a position outside the model ear canal and facing the model ear canal, and further, the speaker and the model ear canal are covered with a sound insulation box to acoustically shield the outside of the sound insulation box. In this state, the sound in the audible frequency band is sweeped out from the speaker and picked up by the microphone to obtain the frequency-sound pressure characteristic.

In the above-mentioned sound collection, the frequency-sound pressure characteristic obtained without the earplug 51 attached to the model ear canal is referred to as an open ear characteristic Cn. Further, the frequency-sound pressure characteristic collected with the earplug 51 attached to the model ear canal is referred to as earplug characteristic C. The earplug characteristic C was acquired each time the axial position of the adjusting portion 2 with respect to the main body portion 1 was changed stepwise.

As shown in FIG. 5, the bare ear characteristic Cn shown by the broken line and the earplug characteristic C shown by the solid line were obtained. The bare ear characteristic Cn and the earplug characteristic C show almost no difference between the two companies in the bass range of about 200 Hz or less, and are shown by a single solid line in FIG. On the other hand, in the band exceeding 200 Hz, the sound pressure exhibited by the earplug characteristic C is reduced with respect to the bare ear characteristic Cn.

Further, when the position of the adjusting portion 2 in the axial direction with respect to the main body portion 1 is changed, the degree of sound pressure attenuation of the earplug characteristic C changes at a frequency near a predetermined (specific) frequency. The predetermined frequency is 1 kHz in this example.

With reference to FIG. 6, the change in the earplug characteristic C according to the position of the adjusting unit 2 will be described in detail. FIG. 6 is an enlarged view of part A in FIG. In FIG. 6, the earplug characteristic C in the first adjusted state of the earplug 51 is represented by the characteristic CMA shown by the solid line, and the earplug characteristic C in the maximum adjusted state is represented by the characteristic CMM shown by the chain line.

In the first adjusted state, the air chamber R is not formed. That is, in this state, the length LR of the air chamber R and the volume VR of the air chamber are 0 (zero). The characteristic CMA in the first adjusted state has a maximum feature point PA at a frequency slightly higher than 1 kHz. As the length LR of the air chamber R and the volume VR of the air chamber R increase by regressing the adjustment unit 2 from the first adjustment state, the sound pressure of the feature point PA that exhibited the maximum decreases and turns to the minimum. , It is shown as a feature point PB in the characteristic CMM in the maximum adjusted state.

The sound pressure difference Ha between the maximum feature point PA and the minimum feature point PB is about 6 dB in the example of FIG. A sound pressure difference of 6 dB in the vicinity of 1 kHz, which is highly audible to the human ear, is sufficient for the user of the earplug 51 to recognize that the sound quality changes. That is, the earplugs 51 can change the sound quality heard by the user by adjusting the axial position of the adjusting unit 2.

The range around 1 kHz corresponds to the range of human voice. Therefore, when the earplug 51 has, for example, the earplug characteristic C, the adjustment unit 2 is advanced toward the back side of the ear canal Ea so that the human voice can be heard with relative emphasis while reducing the background sound. It can be made easier. Further, by retracting the adjusting unit 2 from the back side of the ear canal Ea, it is possible to reduce the sound pressure in a wide range including the listening sound pressure in the range corresponding to the human voice. That is, the earplugs 51 can be used for various purposes.

The embodiment is not limited to the above-described configuration, and can be modified without departing from the gist of the present disclosure.

The earplug 51 has a structure (mechanism) in which the adjusting portion 2 attached to the main body portion 1 is moved back and forth in the axial direction to change the volume of the air chamber R. This structure (mechanism) is not limited to the screwing of the main body portion 1 and the adjusting portion 2, and various structures (mechanisms) can be freely applied. For example, the adjusting portion 2 may be provided so as to be slidable in the axial direction with respect to the main body portion 1 by engaging the concave portion extending in the axial direction with the convex portion. The shape of the air chamber R is not limited to the one having a constant cross-sectional shape orthogonal to the axial direction. For example, in the earplug characteristic C, in order to make the characteristic change accompanying the movement of the adjusting unit 2 desired, the cross-sectional area of the air chamber R orthogonal to the axial direction changes with the movement of the adjusting unit 2. May be good.

The number of air chambers R (number of stages) is not limited to one stage, and may be provided in multiple stages in the axial direction. Markers that can visually determine the axial position of the adjusting unit 2 with respect to the main body 1 may be provided. For example, a notch extending in the axial direction may be provided on the outer peripheral surface of the screwed portion 22 of the adjusting portion 2, and a plurality of marks may be formed on the bottom surface of the notch at a predetermined pitch in the axial direction. As a result, the axial position of the adjusting unit 2 can be grasped depending on which of the plurality of marks is hidden by the base 12 of the main body 1.

FIG. 7 is a cross-sectional view for explaining the earplug 51 according to the modified example. As shown in FIG. 7, the adjusting portion 2 of the earplug 51 according to the modified example may have a tube 22b provided on the tip surface 22a. The tube 22b opens from the periphery of the through hole 23 with the same diameter as the through hole 23, and projects axially toward the air chamber R (in other words, the through hole 122a). Further, as shown by the dotted line in FIG. 7, the air chamber portion 121 of the earplug 51 according to the modified example may have a tube 122b provided on the bottom surface 121b. The tube 122b opens from the periphery of the through hole 122a with the same diameter as the through hole 122a, and projects axially toward the air chamber R (in other words, the through hole 23). Only one of the pipe 22b and the pipe 122b may be provided, or both may be provided. For example, FIG. 7 shows a state in which the earplug 51 having the tube 22b is inserted into the ear canal Ea in the second adjusted state. In FIG. 7, the pipe 22b protruding from the tip surface 22a of the adjusting portion 2 serves as an inner duct in the air chamber R and exerts a sound reducing effect of the silencer.

When the pipe 22b is provided on the tip surface 22a, the tip of the pipe 22b in the first adjustment state comes into contact with the bottom surface 121b of the air chamber portion 121, and the adjustment portion 2 is in a state of being deepest. In this first adjustment state, the through hole 23 of the adjustment portion 2 directly communicates with the through hole 122a of the duct portion 122 of the main body portion 1 concentrically, and the air chamber R is not formed. That is, the ventilation path D that communicates the external space Vg and the internal space Ve of the ear canal Ea is substantially only one linear ventilation path DA.

The disclosures of this application are related to the subject matter described in Japanese Patent Application No. 2018-232371 filed on December 12, 2018, all of which are incorporated herein by reference.

1 Main body 11 Cushion 12 Base 121 Air chamber 121a Female thread 121b Bottom surface 122 Duct 122a Through hole 122b Kan 2 Adjusting part 21 Picking part 21a Lauret 22 Screwing part 22a Tip surface 22b Pipe 221 Male thread part 23 Through hole 51 Plug C Earplug characteristics, CMA, CMM characteristics, Cn Bare ear characteristics da, da1, da2, da3 Inner diameter Ea Ear canal MA, MB Ventilation path model DA, D, DB, Dmax Ventilation path, D1, D2, D3 Duct Ha Sound pressure difference L, LA, L2, L3, LR, LB, L2max Length MA, MB Ventilation model, PA, PB Feature point R Air chamber Ve External auditory canal internal space, Vg External space V2, V3, VA, VR, VB, VBmax volume

Claims (4)

A duct having a first inner diameter air chamber portion with one end open and a first through hole having a second inner diameter smaller than the first inner diameter portion and projecting from the other end portion of the air chamber portion. A main body that has a part and can be attached to the ear canal,
An earplug having a second through hole having a third inner diameter smaller than the first inner diameter, and having an adjusting portion movably attached to the air chamber portion of the main body portion in the axial direction. A claim characterized in that a ventilation path is formed in which the first through hole and the second through hole directly communicate with each other in a state where the tip surface of the adjusting portion is in contact with the bottom surface of the air chamber portion. Item 1. The earplug according to item 1. The first through hole, the second through hole, the first through hole, and the second through hole in a state where the tip surface of the adjusting portion is not in contact with the bottom surface of the air chamber portion. The earplug according to claim 1 or 2, wherein an air chamber formed of a part of the air chamber portion interposed between the earplugs and a ventilation path formed of the air chamber is formed. The earplug according to any one of claims 1 to 3, wherein the adjusting portion is screwed with respect to the air chamber portion and is movable in the axial direction.

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