JP6969208B2 - Ventilation path formation structure in earphones and earphones - Google Patents

Description

The present invention relates to a ventilation path forming structure and an earphone in an earphone, and more particularly to a ventilation path forming structure in an earphone forming a ventilation path having a small ventilation path cross-sectional area and an earphone having the same.

In the earphone, a ventilation path may be provided to allow ventilation between the internal space and the external space of the housing.
For example, in an earplug type (also referred to as a canal type) earphone, the earpiece is in close contact with the inner surface of the ear canal during use, and the degree of sealing between the anterior space and the inner space of the ear canal with respect to the diaphragm is high. Therefore, when the earphone is attached to or detached from the ear, the pressure in the front space may increase or decrease, and a load may be applied to the diaphragm.

Therefore, there is known a technique of providing a ventilation path communicating the front space and the external space in the housing to eliminate the pressure increase / decrease in the front space and reduce the load on the diaphragm.
Further, not limited to the earplug type, there is also known a technique of adjusting the reproduced acoustic characteristics by providing a ventilation path that allows ventilation between the front space or the rear space and the external space with respect to the diaphragm.
Patent Document 1 describes an earphone having these ventilation passages as holes.

Japanese Patent No. 5575435

The earphone housing is often formed by injection molding of resin with an emphasis on cost and mass productivity.
In the mold for injection molding the housing, the pin forming the hole has a predetermined diameter or more in order to have strength to prevent breakage or breakage in mass production molding. The predetermined diameter is generally about 0.8 mm in diameter. That is, it is desirable that the hole formed in the housing has a diameter of about 0.8 mm or more.

On the other hand, when the hole is used as a ventilation path, the difference in the cross-sectional area of the ventilation path determined according to the diameter of the hole is sensitively reflected in the reproduced acoustic characteristics. As a general tendency, as the cross-sectional area of the air passage of the air passage becomes smaller, the sound pressure in the low frequency range increases and a preferable reproduced sound can be obtained. Here, the cross-sectional area of the air passage is the area of the cross section orthogonal to the extending direction (direction in which the substrate flows) of the air passage.
Since the housing volume of the earphone is originally small, it is necessary to make the hole as a ventilation path as small as possible in order to obtain a preferable reproduced sound with improved sound pressure in the low frequency range.
However, as described above, for holes smaller than, for example, about 0.8 mm in diameter, the smaller the diameter of the hole, the higher the possibility that pin breakage will occur in mass production molding and the productivity will decrease.
Therefore, it has been desired to devise a method that can reduce the cross-sectional area of the air passage without reducing the productivity.

Therefore, the problem to be solved by the present invention is a ventilation path forming structure in earphones, which can form a ventilation path connecting the internal space and the external space of the housing with a smaller ventilation path cross-sectional area without reducing productivity. And to provide earphones.

In order to solve the above problems, the present invention has the following configuration.
1) A first through hole formed in the earphone housing and communicating the space on one side with respect to the housing and the space on the other side.
A guide that surrounds the first through hole, which is formed so as to project from the housing.
The inner region of the guide has a second through hole that is smaller than the first through hole so that the second through hole communicates with the first through hole and covers the first through hole. With the ventilation passage forming plate attached to
Equipped with
The first hole space, which is the internal space of the first through hole, and the second hole space, which is the internal space of the second through hole, allow the space on one side and the space on the other side. There is a ventilation path that communicates with
The first through hole, the second through hole, the guide, and the ventilation forming plate are circular.
The second through hole is a ventilation path forming structure in an earphone, characterized in that it is located in the center of the plate.
2) A speaker unit with a diaphragm and
A housing that houses the speaker unit inside and forms a first space on one side of the diaphragm and a second space on the other side.
A first through hole formed in the housing and communicating the external space with the first space or the second space of the housing.
A guide that surrounds the first through hole, which is formed so as to project from the housing.
The inner region of the guide has a second through hole that is smaller than the first through hole so that the second through hole communicates with the first through hole and covers the first through hole. With the ventilation passage forming plate attached to
Equipped with
The external space and the first space or the first space are formed by the first hole space which is the internal space of the first through hole and the second hole space which is the internal space of the second through hole. A ventilation path that communicates with the space of 2 is constructed,
The first through hole, the second through hole, the guide, and the ventilation forming plate are circular.
The second through hole is an earphone characterized in that it is located in the center of the plate.

According to the present invention, there is an effect that a ventilation path connecting the internal space and the external space of the housing can be formed with a smaller ventilation path cross-sectional area.

FIG. 1 is a cross-sectional view for explaining the earphone 51 which is the first embodiment of the earphone according to the embodiment of the present invention. FIG. 2 is a partial rear view for explaining the ventilation path forming structure K1 included in the earphone 51. FIG. 3 is a partial rear view for explaining an aspect of the front housing 1 in the air passage forming structure K1. FIG. 4 is a two-view view for explaining the ventilation path forming plate 6 included in the ventilation path forming structure K1, and is a side view (a) and a plan view (b). FIG. 5 is a perspective assembly diagram for explaining the air passage forming structure K1. FIG. 6 is a partial rear view of the front housing 1 for explaining a modified example of the air passage forming structure K1. FIG. 7 is a partial cross-sectional view for explaining the ventilation path forming structure K2 included in the earphone 52 according to the second embodiment. FIG. 8 is a partial rear view for explaining the ventilation path forming structure K2. 9A and 9B are two views for explaining the air passage forming plate 26 included in the air passage forming structure K2, and are a sectional view (a) and a plan view (b). FIG. 10 is a graph for explaining the reproduction frequency characteristic. FIG. 11 is a partial rear view for explaining a modified example in which the formation positions of the position regulating portions 1b5 and 1b6 are different.

The ventilation path forming structure in the earphone according to the embodiment of the present invention will be described with reference to the ventilation path forming structure K1 of Example 1 and the ventilation path forming structure K2 of Example 2.

(Example 1)
FIG. 1 is a schematic cross-sectional view for explaining an earphone 51 having a ventilation path forming structure K1. For convenience of explanation, the left-right front-back direction is defined as the direction of the arrow shown in FIG. The earphone 51 is an earplug type earphone.

The earphone 51 has a housing 3 in which a front housing 1 and a rear housing 2 are assembled in the front-rear direction.
At least, the front housing 1 is formed by injection molding of resin. An example of the resin is PC (polycarbonate).

The speaker unit 4 is housed inside the housing 3.
The speaker unit 4 has a diaphragm 4a and has a thin flat columnar shape in the front-rear direction. For example, as shown in FIG. 1, the speaker unit 4 is sandwiched and fixed between the front housing 1 and the rear housing 2.
The speaker unit 4 is attached so that the sound emitting surface 4b that outputs sound is on the front side, and the internal space of the housing 3 is separated from the front and rear by the speaker unit 4 in a non-ventilated manner.

The front housing 1 has a body portion 1a having a maximum diameter centered on the central axis CL1, a front wall portion 1b whose diameter is reduced in a substantially conical shape from the body portion 1a to the front, and a center portion from the center portion of the front wall portion 1b. It has a tubular sound cylinder portion 1c formed so as to project forward with the axis CL1 as an axis.
The sound tube portion 1c has a sound emitting hole 1c1 penetrating on the central axis CL1, and the earpiece 5 is detachably attached to the outer peripheral surface. The earpiece 5 is made of a flexible material such as silicone rubber.

Inside the front housing 1, there is a space V1 surrounded by a front wall portion 1b and a speaker unit 4, and a space V2 which is an internal space of a sound emitting hole 1c1 of a sound tube portion 1c connected to the front of the space V1. It is formed.
Further, a space V3, which is an internal space of the earpiece, is connected to the front of the space V2. These spaces V1 to V3 serve as the front space Vf with respect to the diaphragm 4a.

The earphone 51 has a ventilation path forming structure K1 on the front wall portion 1b of the front housing 1. Next, the air passage forming structure K1 will be described with reference to FIGS. 2 to 5.

FIG. 2 is a partial rear view of the air passage forming structure K1 as viewed from the rear side of FIG.
FIG. 3 is a view corresponding to FIG. 2 and shows an aspect of the front housing 1 to which the air passage forming plate 6 is not attached.
4A and 4B are views for explaining a ventilation path forming plate 6, in which FIG. 4A is a side view and FIG. 4B is a front view.
FIG. 5 is a perspective assembly view seen from an oblique rear view for explaining the attachment of the ventilation path forming plate 6 to the front wall portion 1b.
In FIGS. 2 and 3, since the front wall portion 1b is an inclined surface, the rear view is strictly a perspective drawing, but it is described as a plan view drawing for simplification and easy understanding of drawing. .. Hereinafter, the same applies to FIGS. 6 and 8.

The ventilation path forming structure K1 generally extends in an arc shape formed on the rear surface 1b7 of the front wall portion 1b as a through hole 1b1 formed in the front wall portion 1b and penetrating back and forth and a recess connected to the through hole 1b1. It has a groove portion 1b2 and a plate-shaped air passage forming plate 6 attached so as to cover at least a through hole 1b1 and a part of the groove portion 1b2.
The through hole 1b1 is a hole that communicates the space on one side with respect to the front wall portion 1b and the space on the other side.

Further, the ventilation path forming structure K1 may have an inner guide rib 1b3 formed radially inward with respect to the groove portion 1b2 and an outer guide rib 1b4 formed on the outer side, and hereinafter includes these. The configuration will be described in detail.

The front housing 1 is formed with the direction of the central axis CL1 shown in FIG. 1 as the mold opening direction DRa on injection molding.
The through hole 1b1 is formed in the front wall portion 1b as a hole that extends in the mold opening direction DRa and communicates with the inside and outside of the front housing 1.
That is, the through hole 1b1 is formed by, for example, a pin erected on the core in a mold in which a core and a cavity are assembled in injection molding.
The through hole 1b1 is shaped so that the pin standing on the core has sufficient strength to withstand mass production molding. For example, it is a circular hole with a diameter of 0.8 mm.

The groove portion 1b2 formed by connecting to the through hole 1b1 is formed in an arc shape centered on the central axis CL1 in the rear view.
The radial cross-sectional shape (cross-sectional shape) of the groove portion 1b2 is not limited. For example, it may be rectangular, semicircular, triangular, or a combination thereof.
The groove portion 1b2 may or may not have a cross-sectional area Sm constant along the extending direction of the arc shape.
If it is constant, the cross-sectional area Sm is constant, and if it is not constant, the minimum cross-sectional area is the air passage cross-sectional area S (see FIG. 5) as described later.
Here, an example will be described in which the groove portion 1b2 is formed in a shape in which the cross-sectional area Sm is constant.

As shown in FIG. 4, the air passage forming plate 6 has a constant width W6 between the radii R6a and the radius R6b and a circumferential length L6 in the range of the center angle θ6 with respect to the virtual center CL6. It is an arc-shaped plate member having a thickness of t6.
The material of the air passage forming plate 6 is not limited as long as it does not have air permeability. For example, it is a PET (polyethylene terephthalate) resin.
The width W6 and the circumferential length L6 are set to have a shape and size that completely covers the through hole 1b1 formed in the front wall portion 1b.
The ventilation path forming plate 6 can cover the through hole 1b1 and the whole or at least a part of the groove portion 1b2 connected to the through hole 1b1.

As shown in FIG. 3, the inner guide rib 1b3 is formed as an arcuate curved surface having an outer surface 1b3a having a radius R3a centered on the central axis CL1.
The outer guide rib 1b4 is formed as a curved surface having an inner side surface 1b4a having a radius R3b centered on the central axis CL1.
Here, the radius R3a is set to a value slightly smaller than the radius R6a of the air passage forming plate 6, and the radius R3b is set to a value slightly larger than the radius R6b of the air passage forming plate 6.
Therefore, as shown in FIG. 2, the ventilation path forming plate 6 can be accommodated between the inner guide rib 1b3 and the outer guide rib 1b4 in a radially positioned state.

The ventilation path forming plate 6 is attached to the region between the inner guide ribs 1b3 and the outer guide ribs 1b4 on the rear surface 1b7 of the front wall portion 1b with an adhesive or double-sided tape.
The ventilation path forming plate 6 is attached to the rear surface 1b7 by an operator or a working robot so as to cover the opening 1b1a (FIG. 3) of the through hole 1b1 and at least a part of the groove portion 1b2 connected to the through hole 1b1. ..
As a result, of the through hole 1b1 and the groove portion 1b2, only the end portion of the groove portion 1b2 on the side far from the through hole 1b1 is exposed as the opening portion 1b2a of the groove portion 1b2 without being covered by the ventilation path forming plate 6. (See Fig. 2).

The ventilation path forming structure K1 extends from the inner guide ribs 1b3 and the outer guide ribs 1b4 along the radius line LNR (FIGS. 2 and 3) passing through the central axis CL1 so as to approach the respective mating sides, and the position restricting portion 1b5 and It may have a position regulating unit 1b6.
The position-regulating portion 1b5 and the position-regulating portion 1b6 guide the mounting position of the air passage forming plate 6 in the circumferential direction. That is, the operator can attach the ventilation path forming plate 6 to a predetermined circumferential position without worrying about fine positioning simply by applying the ventilation path forming plate 6 to the position regulating portions 1b5 and 1b6, and the attachment is easy. ..
The position restricting unit 1b5 and the position restricting unit 1b6 serve as a visible guide that at least visually guides the mounting position of the ventilation path forming plate 6 to the operator.

The length L6 in the circumferential direction of the ventilation path forming plate 6 and the forming position of the position restricting portions 1b5 and 1b6 are such that the ventilation path forming plate 6 covers the through hole 1b1 and a part of the groove portion 1b2 and the through hole of the groove portion 1b2. The position is such that the end portion on the side far from 1b1 is not covered and is attached so as to be the opening portion 1b2a of the groove portion 1b2 (see FIG. 2).

In the ventilation path forming structure K1 described above, the through hole 1b1, the groove portion 1b2, and the ventilation path forming plate 6 form a ventilation path TR that communicates the inner and outer spaces of the front wall portion 1b.
More specifically, the ventilation passage TR is formed by a hole space which is an internal space of the through hole 1b1 and a groove space which is a space surrounded by the groove portion 1b2 and the ventilation passage forming plate 6. The groove space is a space in which one end side is connected to the hole space and the other end side is opened as an opening 1b2a.

In the air passage forming structure K1, the air passage cross-sectional area S can be made smaller than the hole cross-sectional area Sh of the through hole 1b1 by setting the cross-sectional shape and dimensions of the groove portion 1b2.
For example, when the through hole 1b1 is a hole having a diameter of 0.8 mm, the hole cross-sectional area Sh is about 0.50 mm ² .
Here, if the groove portion 1b2 is formed with a width of 0.7 mm and a depth of 0.1 mm, the air passage cross-sectional area S is 0.07 mm ² , which is smaller than the hole cross-sectional area Sh.
Therefore, the ventilation path TR can be set to have a significantly smaller ventilation path cross-sectional area as compared with the case where the ventilation path is simply formed by the through hole 1b1.

In the air passage forming structure K1, the portion on the core side that forms the groove portion 1b2 by injection molding is not a pin built on the core surface but a rib-shaped portion protruding on the core surface, so that the durability of the mold is that of the pin. Higher than the case.
Therefore, even if the width and depth of the groove portion 1b2 are reduced, there is a low possibility that a problem such as breakage or breakage will occur in mass production molding. In particular, by reducing the depth of the groove portion 1b2 and widening the width, the corresponding core side becomes a convex portion having a short height and a large width, so that the durability of the mold is further improved.

In the earphone 51 having the above-mentioned ventilation path forming structure K1, a ventilation path TR that communicates the front space Vf and the external space Vg is formed in the front wall portion 1b of the front housing 1.
Then, by setting the cross-sectional area Sm of the groove portion 1b2, the air passage cross-sectional area S of the air passage TR can be easily obtained as a cross-sectional area smaller than the hole cross-sectional area Sh of the through hole 1b1.
Therefore, the earphone 51 has a high sound pressure in the low frequency range and good reproduced acoustic characteristics without improving the strength of the pin for forming the through hole 1b1 and lowering the productivity. Further, the pressure increase / decrease in the front space Vf when the earphone 51 is attached / detached to / from the ear is eliminated, and the load on the diaphragm 4a is reduced.

When the inner guide ribs 1b3 and the outer guide ribs 1b4 are provided, the ventilation path forming structure K1 has a radial shape centered on the central axis CL1 in the attachment region of the ventilation path forming plate 6 between them, as shown in FIG. The guide line Lg may be formed. FIG. 6 shows an example in which three guide lines Lg1 to Lg3 having different distances from the through hole 1b1 are visibly provided. The guide wire Lg can be formed, for example, by inserting a scribe line on the surface of the core.

The guide wire Lg serves as a guide for the position in the circumferential direction when the operator attaches the ventilation path forming plate 6. That is, the guide line Lg is a visible guide that at least visually guides the attachment position of the ventilation path forming plate 6 to the operator.
By attaching the end position of the ventilation path forming plate 6 not only to the position regulating portions 1b5 and 1b6 but also to each guide line Lg1 to Lg3, the operator can easily install the ventilation path TR having different lengths. Each can be obtained with high accuracy.
In general, the length (duct length) of the air passage (duct) communicating inside and outside the housing affects the reproduced acoustic characteristics as in the air passage cross-sectional area S, so the mounting position of the air passage forming plate 6 is changed. The length of the air passage TR can be changed to adjust the sound quality.
By providing the position restricting portions 1b5 and 1b6 and the guide wire Lg, it is possible to suppress the variation in work and accurately adjust the length of the ventilation path TR to a constant value.

As described in detail above, in the ventilation path forming structure K1 of the first embodiment, the ventilation path TR communicating the inner space and the outer space of the front wall portion 1b is covered with the front wall portion 1b of the ventilation path forming plate 6. By wearing, it is configured by a combination of the entire through hole 1b1 and the portion of the groove portion 1b2 on the side connected to the through hole 1b1.
Therefore, the cross-sectional area Sm of the groove portion 1b2 can be made smaller than the hole cross-sectional area Sh of the through hole 1b1 as the ventilation path cross-sectional area S.
Thereby, the ventilation path TR communicating the front space Vf and the external space Vg of the front housing 1 can be formed with a smaller ventilation path cross-sectional area S without reducing the productivity.

(Example 2)
Next, the ventilation path forming structure K2 of the second embodiment will be described with reference to FIGS. 7 to 9.
The air passage forming structure K2 includes a front housing 21 having a different shape and an air passage forming plate 26 corresponding to the front housing 1 and the air passage forming plate 6 in the air passage forming structure K1 of the first embodiment, respectively. ..
The earphone 52 is the same as the earphone 51 except that the ventilation path forming structure K1 is formed into the ventilation path forming structure K2 with respect to the earphone 51.

FIG. 7 is a partial cross-sectional view showing a main part of the earphone 52 corresponding to the part A of FIG.
FIG. 8 is a view of the A portion and its vicinity as viewed from the rear.
9A and 9B are two views for explaining the air passage forming plate 26, where FIG. 9B is a plan view and FIG. 9A is a cross-sectional view taken along the line (b) at the S1-S1 position.

The front housing 21 has a through hole 21b1 corresponding to the through hole 1b1 of the front housing 1.
An annular guide rib 21b3 surrounding the through hole 1b1 is formed so as to project rearward on the rear surface 21b7 of the front wall portion 21b of the front housing 21.
A disk-shaped air passage forming plate 26 is attached to the inner circular region of the guide rib 21b3 by an adhesive or double-sided tape.

As shown in FIG. 9, the air passage forming plate 26 has a disk shape and has a through hole 26a at the center position. The ventilation path forming plate 26 is made of a soft resin plate that can be easily punched, and is, for example, a resin plate such as PET.
The hole cross-sectional area Sm2 of the through hole 26a is smaller than the hole cross-sectional area Sh2 of the through hole 21b1. That is, the diameter φc of the through hole 26a is smaller than the diameter φb of the through hole 21b1. For example, the diameter φb = 0.8 mm and the diameter φc = 0.3 mm.

When the operator attaches the ventilation path forming plate 26 to the inner region of the guide rib 21b3, the through hole 26a is positioned at a position communicating with the through hole 21b1. Installation of the ventilation path forming plate 26 by an operator is easy because the guide ribs 21b3 are visibly projected.
That is, as shown in FIG. 7, the air passage TR2 communicating inside and outside the front housing 21 is composed of the through hole 21b1 and the through hole 26a, and the minimum air passage cross-sectional area S2 is the hole of the through hole 26a. The cross-sectional area is Sm2.
When the diameter φc of the through hole 26a is 0.3 mm, the hole cross-sectional area Sm2 is 0.07 mm ² .

The ventilation path forming structure K2 of the second embodiment includes a through hole 21b1 and a through hole 26a to form a ventilation path TR2 that communicates inside and outside the front housing 21.
Specifically, the through hole 21b1 provided in the front housing 21 formed by injection molding is formed with a diameter φb having a size that maintains productivity without causing problems with the pins of the mold. Then, a ventilation path forming plate 26 having a through hole 26a having an opening area smaller than that of the through hole 21b1 is attached to the rear surface 21b7 of the front wall portion 21b in the front housing 21 so that the through hole 21b1 opens only in the through hole 26a. The cross-sectional area of the air passage TR2 can be made smaller than the cross-sectional area of the through hole 21b1.

Since the axial length of the through hole 26a is changed by changing the thickness of the ventilation path forming plate 26, the length of the ventilation path TR2 can be substantially changed.
Further, the length of the air passage TR2 can be substantially changed by stacking and mounting the plurality of air passage forming plates 26.

Since the earphone 51 of the first embodiment and the earphone 52 of the second embodiment have the ventilation path forming structure K1 and the ventilation path forming structure K2, respectively, high sound pressure in the low frequency range can be obtained in terms of reproduced acoustic characteristics.
FIG. 10 is a graph for explaining the difference in the reproduced acoustic characteristics depending on the presence or absence of the air passage forming structure K1.
In FIG. 10, the characteristic of the broken line shows the characteristic when the front housing 1 is provided with the ventilation path having the ^{ventilation path cross-sectional area S of 0.50 mm 2 only by the through hole 1b1 having a diameter of 0.8 mm.} Further, the characteristics of the solid line show the characteristics when the front housing 1 is provided with the ventilation path forming structure K1 having ^{the ventilation path cross-sectional area S of 0.07 mm 2.}
As is clear from FIG. 10, by providing the ventilation path forming structure K1, the sound pressure rise is recognized in the low frequency range of about 500 Hz or less, and the reproduced acoustic characteristic excellent in the volume of bass is obtained even though it is an earphone. You can see that it is done.

The embodiment described in detail above is not limited to the above-mentioned configuration, and may be a modified example that is modified within a range that does not deviate from the gist of the present invention.

The earphones 51 and 52 have ventilation path forming structures K1 and K2 in the rear housing 2, respectively, and have a structure that communicates between the rear space Vb (see FIG. 1) with respect to the diaphragm 4a of the speaker unit 4 and the external space Vg. May be. Also in this case, the reproduced acoustic characteristics of the earphones 51 and 52 can be adjusted, and good reproduced acoustic characteristics can be obtained.

In the ventilation path forming structure K1 of the first embodiment, the internal space and the external space may be reversed. That is, the groove portion 1b2 may be formed on the front surface 1b8 (FIG. 1) which is the outside of the front housing 1, and the ventilation path forming plate 6 may be attached to the front surface 1b8.

In the ventilation path forming structures K1 and K2 of Examples 1 and 2, the through holes 1b1, 21b1 do not have to be circular holes, and the cross-sectional shape and opening shape of the holes are not limited.
Further, the extending shape and extending direction of the groove portion 1b2 in the ventilation path forming structure K1 are not limited to the arc shape and the circumferential direction, and may be, for example, a straight shape and a radial direction.

As shown in FIG. 11, the position restricting portions 1b5 and 1b6 of the ventilation path forming structure K1 of the first embodiment are end portions on the through hole 1b1 side in the inner guide ribs 1b3 and the outer guide ribs 1b4 (upper side end portions in FIG. 11). In addition, it may be formed along a radius line.
In this case, by attaching the ventilation path forming plates 6 having different circumferential lengths L6 with the position restricting portions 1b5 and 1b6 as the positioning reference, the ventilation passages TR having different lengths can be formed.

1,21 Front housing 1a Body, 1b, 21b Front wall, 1b1,21b1 Through hole 1b2 Groove, 1b2a Opening, 1b3 Inner guide rib 1b3a Outer side, 1b4 Outer guide rib, 1b4a Inner side 1b5, 1b6 Position control part, 1b7 , 21b7 Rear surface 1c sound tube part, 1c1 sound release hole 2 rear housing
3 Housing 4 Speaker unit, 4a Diaphragm, 4b Sound emitting surface 5 Earpiece 6,26 Ventilation path forming plate 21b3 Guide rib 26a Through hole 51,52 Earphone CL1 Center axis, CL6 Virtual center DRa type Opening direction K1, K2 Ventilation path forming structure Lg, Lg1 to Lg3 guide line, LNR radius line R3a, R3b, R6a, R6b radius S, S2 ventilation path cross-sectional area Sh, Sh2, Sm2 hole cross-sectional area, Sm cross-sectional area t6 thickness TR, TR2 ventilation path Vb rear space, Vf front space, Vg external space V1 to V3 space φb, φc diameter

Claims (6)

A first through hole formed in the earphone housing and communicating the space on one side with respect to the housing and the space on the other side.
A guide that surrounds the first through hole, which is formed so as to project from the housing.
The inner region of the guide has a second through hole that is smaller than the first through hole so that the second through hole communicates with the first through hole and covers the first through hole. With the ventilation passage forming plate attached to
Equipped with
The first hole space, which is the internal space of the first through hole, and the second hole space, which is the internal space of the second through hole, allow the space on one side and the space on the other side. is constituted ventilation path communicating the,
The first through hole, the second through hole, the guide, and the ventilation forming plate are circular.
The ventilation path forming structure in the earphone, characterized in that the second through hole is located in the center of the plate. The ventilation path forming structure in an earphone according to claim 1, wherein the ventilation path has a cross-sectional area of the second hole space smaller than the cross-sectional area of the first hole space. The ventilation path forming structure in an earphone according to claim 1 or 2, wherein the guide is at least visually recognizable. A speaker unit with a diaphragm and
A housing that houses the speaker unit inside and forms a first space on one side of the diaphragm and a second space on the other side.
A first through hole formed in the housing and communicating the external space with the first space or the second space of the housing.
A guide that surrounds the first through hole, which is formed so as to project from the housing.
The inner region of the guide has a second through hole that is smaller than the first through hole so that the second through hole communicates with the first through hole and covers the first through hole. With the ventilation passage forming plate attached to
Equipped with
The external space and the first space or the first space are formed by the first hole space which is the internal space of the first through hole and the second hole space which is the internal space of the second through hole. A ventilation path that communicates with the space of 2 is constructed ,
The first through hole, the second through hole, the guide, and the ventilation forming plate are circular.
An earphone characterized in that the second through hole is located in the center of the plate. The earphone according to claim 4, wherein the ventilation path has a cross-sectional area of the second hole space smaller than the cross-sectional area of the first hole space. The earphone according to claim 4 or 5, wherein the guide is at least visually recognizable.

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