JP3868851B2 - Electroacoustic transducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrodynamic electroacoustic transducer configured to be attached to a substrate.
[0002]
[Prior art]
In general, an electrodynamic electroacoustic transducer (such as a speaker or a microphone) includes a diaphragm, a voice coil having one end fixed to the diaphragm, and a cylindrical magnet that houses the other end of the voice coil. And a magnetic circuit unit in which a gap is formed.
[0003]
At that time, many of the small electroacoustic transducers are configured to be attached to a substrate of an external device (for example, a mobile phone or a handset). Only the sound radiated toward the front space of the acoustic transducer tends to cause insufficient sound pressure in the low frequency range.
[0004]
Therefore, a function that uses not only sound radiated from the diaphragm toward the front space of the electroacoustic transducer but also sound radiated toward the back space of the electroacoustic transducer (so-called backload function). In order to improve the frequency characteristics of sound pressure, a device has been devised.
[0005]
For example, in International Publication No. WO00 / 21330, a predetermined opening is formed in a case of an external device to which an electroacoustic transducer is attached, so that the diaphragm is radiated from the diaphragm to the back space of the electroacoustic transducer. The device has been devised to guide the sound to the front space of external equipment.
[0006]
Also, in International Publication WO00 / 59263, a plurality of through holes are formed in an adapter for mounting an electroacoustic transducer to an external device so that the back space and the front space of the electroacoustic transducer communicate with each other. Thus, a device for guiding the sound radiated from the diaphragm to the back space of the electroacoustic transducer to the front space is devised.
[0007]
[Problems to be solved by the invention]
However, the conventional electroacoustic transducer has the following problems.
[0008]
That is, in the electroacoustic transducer described in International Publication WO00 / 21330, it is necessary to form an opening in the case of the external device in order to provide a backload function. Depending on the case, it is often difficult to form the opening in the case of the external device, and thus there is a problem of lack of versatility.
[0009]
On the other hand, the electroacoustic transducer described in International Publication WO 00/59263 is configured to have a backload function using an adapter, so that versatility can be ensured. Even when a mounting structure that does not require an adapter is employed when mounting the electroacoustic transducer on an external device, a member in which a plurality of through holes similar to the adapter are formed is required. For this reason, there is a problem that an extra member is required to provide the backload function, and an extra man-hour is required. There is also a problem that a space required for mounting the electroacoustic transducer on an external device becomes large.
[0010]
The present invention has been made in view of such circumstances, and in an electrodynamic electroacoustic transducer configured to be capable of being attached to a substrate, an extra member and its mounting man-hour are required. It is an object of the present invention to provide an electroacoustic transducer that can have a backload function with a compact configuration.
[0011]
[Means for Solving the Problems]
The present invention is intended to achieve the above object by providing a backload function to the case of the electroacoustic transducer itself.
[0012]
That is, the electroacoustic transducer according to the present invention is
An electrodynamic electroacoustic transducer configured to be attached to a substrate,
A diaphragm, a voice coil having one end fixed to the diaphragm, a magnetic circuit unit having a cylindrical magnetic gap for accommodating the other end of the voice coil, and the diaphragm, voice coil, and magnetic circuit A case for housing the unit,
A front sound emission opening for radiating sound from the diaphragm toward the front space of the electroacoustic transducer, and sound from the diaphragm toward the back space of the electroacoustic transducer. A rear sound emission opening for radiating and a backload sound emission passage for guiding sound radiated to the back space through the back sound emission opening to the front space are formed. It is characterized by that.
[0013]
The “electroacoustic transducer” is not particularly limited as long as it is an electrodynamic electroacoustic transducer, and for example, a small speaker, buzzer, microphone, receiver, or the like can be employed.
[0014]
The “diaphragm”, “voice coil”, and “magnetic circuit unit” are not particularly limited as long as they can be used as components of an electrodynamic electroacoustic transducer. .
[0015]
As long as the “case” is configured to accommodate the diaphragm, the voice coil, and the magnetic circuit unit, the specific configuration of the outer shape, material, and the like is not particularly limited.
[0016]
The “backload sound emission passage” is formed so as to be able to guide the sound radiated to the back space through the back sound emission opening to the front space, its shape, size, route The specific configuration such as is not particularly limited.
[0017]
[Effects of the invention]
As shown in the above configuration, the electroacoustic transducer according to the present invention includes a diaphragm, a voice coil, and a magnetic circuit unit in a case, in addition to the front sound emission opening and the rear sound emission opening. Since the sound emission passage for backload is formed to guide the sound radiated to the back space of the electroacoustic transducer through the back sound emission opening to the front space, the following effects are obtained. be able to.
[0018]
That is, since the case of the electroacoustic transducer itself is configured to have a backload function, an extra member and its portion are compared with the case where the adapter is provided with a backload function as in the prior art. The backload function can be provided without requiring installation man-hours, and the backload function can be provided with a compact configuration.
[0019]
As described above, according to the present invention, in the electrodynamic electroacoustic transducer configured to be able to be attached to the substrate, the backloading can be performed in a compact configuration without requiring extra members and installation man-hours. Can have a function.
[0020]
As described above, the specific configuration of the “backload sound emission passage” is not particularly limited. For example, the backload sound emission passage is configured by a groove-like recess formed on the outer peripheral surface of the case. However, depending on the shape or the like of the external device to which the electroacoustic transducer is to be mounted, if the sound emission passage for backloading is constituted by one or a plurality of through holes penetrating the case. In addition, the backload function can be secured.
[0021]
At this time, the “through hole” may be formed so as to extend linearly, but if this is formed so as to extend in the circumferential direction along the magnetic circuit unit, the sound emission passage for backloading is compared. Therefore, it is possible to secure a desired frequency characteristic easily.
[0022]
In the above configuration, the outer shape of the case may be set to a circular shape or the like when viewed from the front. However, if this is set to a substantially rectangular shape when viewed from the front, the electroacoustic transducer can be easily oriented. Therefore, the electroacoustic transducer can be accurately attached to the substrate of the external device in a predetermined direction.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
FIG. 1 is a side cross-sectional view showing an electroacoustic transducer 10 according to an embodiment of the present invention in a state where the electroacoustic transducer 10 is arranged so that the front surface is on the top. 2 and 3 are a plan view and a bottom view thereof.
[0025]
As shown in these drawings, the electroacoustic transducer 10 according to the present embodiment is a small electrodynamic speaker, and is used in a state where it is mounted on an external device such as a mobile phone as will be described later. It has become.
[0026]
The electroacoustic transducer 10 includes a diaphragm 12, a voice coil 14, a magnetic circuit unit 16, a terminal unit 18, a fixing ring 20, and a case 22 for housing them.
[0027]
The case 22 is an injection-molded product made of synthetic resin, and its outer shape is set to a substantially rectangular shape (specifically, a square shape) when viewed from the front (the state shown in FIG. 2). A columnar accommodation space C1 is formed.
[0028]
The diaphragm 12 is a diaphragm-like member having a plurality of concavities and convexities formed concentrically, and is formed by subjecting a synthetic resin film to hot press molding. The diaphragm 12 is fixed to the case 22 via the fixing ring 20 at the outer peripheral flat portion 12a, and the upper end portion (one end portion) of the voice coil 14 is bonded to the intermediate flat portion 12b. It is fixed.
[0029]
The magnetic circuit unit 16 includes a steel base 24, a magnet 26, and a steel yoke 28.
[0030]
The base 24 has an upward flange portion 24B formed on the inner peripheral edge of the ring-shaped flat plate portion 24A, and has four notches 24a extending from the ring-shaped flat plate portion 24A to the upper edge of the upward flange portion 24B at four circumferential directions. Are formed at intervals of 90 °. The magnet 26 is a ring-shaped member having an inner diameter larger than the outer diameter of the upward flange portion 24B of the base 24 by a predetermined dimension, and is fixed to the upper surface of the ring-shaped flat plate portion 24A of the base 24 concentrically with the base 24. Yes. The yoke 28 is a ring-shaped member having an inner diameter slightly smaller than the inner diameter of the magnet 26, and is fixed to the upper surface of the magnet 26 concentrically with the magnet 26. An annular recess 28 a for avoiding interference with the diaphragm 12 is formed in a portion near the inner periphery of the upper surface of the yoke 28. The outer diameters of the base 24, the magnet 26, and the yoke 28 are set to substantially the same value as the diameter of the accommodation space C1 of the case 22.
[0031]
The magnetic circuit unit 16 is accommodated in the case 22, and the lower end (the other end) of the voice coil 14 is interposed between the outer peripheral surface of the upward flange portion 24 </ b> B of the base 24 and the inner peripheral surface of the yoke 28. The cylindrical magnetic gap for accommodating the portion) is formed with the same width all around. At this time, the magnetic circuit unit 16 is inserted into the housing space C1 of the case 22 from below, and the housing 28 is placed in a state where the outer peripheral edge of the upper surface of the yoke 28 is in contact with the outer peripheral flat portion 12a of the diaphragm 12. It is fixed to the peripheral wall surface 22a of C1.
[0032]
The terminal unit 18 includes a terminal board 34 in which two terminal plates 30 and 32 are arranged at a predetermined interval on the upper surface, a board support member 36 for mounting and fixing the terminal board 34, a large-diameter coil spring 38, and the like. The small-diameter coil spring 40 is fixedly supported at the center of the magnetic circuit unit 16.
[0033]
Coil terminals 14a and 14b of the voice coil 14 are fixed to the terminal plates 30 and 32 by thermocompression bonding or the like. In addition, coil spring insertion holes are formed at positions away from the coil terminal fixing portions in the terminal plates 30 and 32, and large-diameter coil springs 38 arranged substantially concentrically in these coil spring insertion holes. The upper end portions 38a and 40a of the small-diameter coil spring 40 are inserted from below. The large-diameter coil spring 38 and the small-diameter coil spring 40 are fixed to the upper surfaces of the terminal plates 30 and 32 by soldering at the upper end portions 38a and 40a. The large-diameter coil spring 38 has a relatively thick wire diameter and is formed so that the winding diameter gradually increases toward the lower end portion thereof, while the small-diameter coil spring 40 has a relatively thin wire diameter. The winding diameter is gradually reduced toward the lower end.
[0034]
The substrate support member 36 is fixed to the base 24 so as to be fitted into the upward flange portion 24B of the base 24 of the magnetic circuit unit 16 from below. At that time, the outer peripheral flange portion formed at the lower end portion of the outer peripheral surface of the substrate support member 36 is brought into contact with the base 24 so that the insertion amount is set. Notches 36 a are formed at 90 ° intervals at four locations in the circumferential direction on the outer periphery of the substrate support member 36. These notches 36a are circumferentially aligned with the notches 24a of the base 24 when the substrate support member 36 is inserted and fixed to the base 24, and the notches 36a and notches 24a and 4 sound emitting holes are formed.
[0035]
The case 22 includes a front sound emission opening 22 b for radiating sound from the diaphragm 12 toward the front space of the electroacoustic transducer 10, and from the diaphragm 12 toward the back space of the electroacoustic transducer 10. Back sound emission opening 22c for radiating sound, and sound radiated to the back space of electroacoustic transducer 10 through back sound emission opening 22c are guided to the front space of electroacoustic transducer 10. For this purpose, a backload sound emission passage 22d is formed.
[0036]
The front sound emission opening 22b is formed in a circular cross-sectional shape having a slightly smaller diameter than the peripheral wall surface 22a of the accommodation space C1 of the case 22 at the upper part of the case 22, and the accommodation space C1 is formed in front of the electroacoustic transducer 10. It is designed to communicate with the space. The rear sound emission opening 22 c is configured as a part of the peripheral wall surface 22 a of the accommodation space C <b> 1 at the lower part of the case 22. The backload sound emission passage 22 d is formed so as to penetrate the case 22 on the outer peripheral side of the accommodation space C <b> 1 in the case 22. At this time, the sound emission passage 22d for backloading includes a ring-shaped groove 22d1 extending from the lower end surface of the case 22 to the vicinity of the upper end surface so as to surround the accommodation space C1 in a ring shape, and the ring-shaped groove 22d1 from It consists of a plurality (12) of through holes 22d2 extending to the end face. Each of these through holes 22d2 has an oval cross-sectional shape extending in an arc shape along the ring-shaped groove 22d1.
[0037]
The magnetic circuit unit 16 is formed such that the lower surface of the base 24 is positioned slightly above the lower end surface of the case 22. On the other hand, the terminal unit 18 is formed such that the lower surface of the substrate support member 36 is located slightly below the lower end surface of the case 22. The large-diameter coil spring 38 and the small-diameter coil spring 40 of the terminal unit 18 are formed such that their lower end portions protrude downward from the lower end surface of the case 22 by a predetermined amount.
[0038]
In the electroacoustic transducer 10 according to the present embodiment, when the diaphragm 12 vibrates, sound is emitted toward the front space of the electroacoustic transducer 10 through the front sound emitting opening 22b of the case 22, and Sound is directed toward the back space of the electroacoustic transducer 10 through the sound emitting hole formed by the notched portion 24 a of the magnetic circuit unit 16 and the notched portion 36 a of the terminal unit 18 and the back sound emitting opening 22 c of the case 22. Further, the sound radiated to the back space of the electroacoustic transducer 10 through the rear sound emission opening 22c is further converted into the front space of the electroacoustic transducer 10 through the backload sound emission passage 22d. It comes to lead to.
[0039]
FIG. 4 is a side cross-sectional view showing the electroacoustic transducer 10 according to the present embodiment in a state where the electroacoustic transducer 10 is mounted on the mobile phone 100.
[0040]
As shown in the figure, the electroacoustic transducer 10 according to the present embodiment is attached to the substrate 104 of the mobile phone 100 by spring pressing inside the case 102 of the mobile phone 100.
[0041]
A plurality of sound emitting holes 102 a are formed in the front portion of the electroacoustic transducer 10 in the case 102 of the mobile phone 100. Further, on the inner surface of the case 102, a flange portion 102b that protrudes along the outer shape of the case 22 of the electroacoustic transducer 10, and a plurality of case receiving portions 102c that protrude at the inner peripheral side corner portion of the flange portion 102b. And are formed.
[0042]
A plurality of openings 104 a are formed in the substrate 104 of the mobile phone 100. Two terminal plates 106 and 108 are arranged on the upper surface of the substrate 104.
[0043]
The electroacoustic transducer 10 is attached to the mobile phone 100 by fitting the case 22 of the electroacoustic transducer 10 on the inner peripheral side of the flange portion 102b until it contacts the case receiving portion 102c of the case 102 of the mobile phone 100. By temporarily fixing to the case 102 and pressing the large-diameter coil spring 38 and the small-diameter coil spring 40 of the electroacoustic transducer 10 against the terminal plates 106 and 108 of the substrate 104 of the mobile phone 100 in this temporarily fixed state. To be done.
[0044]
When the electroacoustic transducer 10 is driven in the state of being attached to the cellular phone 100 in this way and the diaphragm 12 vibrates, the front acoustic sounding opening 22b is passed to the front space of the electroacoustic transducer 10. The sound radiated toward is emitted to the front space of the mobile phone 100 through the sound emission hole 102a of the case 102 and is also transmitted through the back sound emission opening 22c of the electroacoustic transducer 10 to the electroacoustic transducer. The sound radiated toward the back space 10 is radiated to the internal space C2 of the mobile phone 100 through the opening 104a of the substrate 104, and the sound radiated to the internal space C2 is The light is emitted to the front space of the mobile phone 100 through the portion 104 a, the backload sound emission passage 22 d of the case 22, and the sound emission hole 102 a of the case 102.
[0045]
As described above in detail, the electroacoustic transducer 10 according to the present embodiment includes the front sound emitting opening 22b and the rear sound emission in the case 22 that houses the diaphragm 12, the voice coil 14, and the magnetic circuit unit 16. In addition to the opening 22c for the back, a sound emission passage 22d for backload for guiding the sound radiated to the back space of the electroacoustic transducer 10 through the back sound emission opening 22c to the front space is formed. Therefore, the following effects can be obtained.
[0046]
That is, since the case 22 itself of the electroacoustic transducer 10 is configured to have a backload function, an extra member is provided as compared with the case where the adapter is provided with a backload function as in the prior art. In addition, it is possible to provide a backload function without requiring man-hours for mounting, and to provide a backload function with a compact configuration.
[0047]
At this time, in the present embodiment, the ring-shaped groove portion 22d1 penetrating the case 22 and the plurality of through holes 22d2 constitute the sound emission passage 22d for backloading. The backload function can be ensured without depending on the shape of the device.
[0048]
In addition, in the present embodiment, since the outer shape of the case 22 is set to be substantially rectangular (square) when viewed from the front, the direction of the electroacoustic transducer 10 can be easily grasped, thereby the electroacoustic transducer. 10 can be placed on the substrate 104 of the mobile phone 100 with a predetermined orientation with high accuracy.
[0049]
Next, a first modification of the above embodiment will be described.
[0050]
FIG. 5 is a plan view showing an electroacoustic transducer 50 according to this modification, and FIG. 6 is a perspective view showing the case 52 as a single product.
[0051]
The electroacoustic transducer 50 is configured according to the above-described embodiment with respect to the configuration other than the case 52 and the configuration of the peripheral wall surface 52a, the front sound emitting opening 52b, and the back sound emitting opening 52c. 10 is the same.
[0052]
In this modification, the backload sound emission passage 52d is formed in each corner portion of the case 52 by four columnar through holes penetrating the case 52 in the vertical direction.
[0053]
Even in the case of adopting the configuration of this modification, it is possible to obtain the same effects as those of the above embodiment. In addition, in the present modification, the backload sound emission passage 52d is disposed in each corner portion of the case 52, so that the case 52 can be configured more compactly than the above embodiment.
[0054]
Next, a second modification of the above embodiment will be described.
[0055]
FIG. 7 is a plan view showing an electroacoustic transducer 60 according to this modification, and FIG. 8 is a perspective view showing the case 62 as a single product.
[0056]
The electroacoustic transducer 60 has the configuration other than the case 62 and the configurations of the peripheral wall surface 62a, the front sound emitting opening 62b, and the back sound emitting opening 62c of the case 62 according to the above embodiment. 10 is the same.
[0057]
In the present modification, the backload sound emission passage 62d is formed in the case 62 so as to extend in the circumferential direction along the accommodation space C1.
[0058]
In other words, the case 62 includes a case main body 62A in which the accommodation space C1 is formed, and a pair of covers 62B fixed to the case main body 62A.
[0059]
The case main body 62A has a pair of space portions 62d1 opened downward on both sides of the accommodation space C1. The pair of corner portions located on the diagonal line are provided with the space portion 62d1 facing the front. An opening 62d2 communicating with the space is formed. On the other hand, each cover 62B is made of a plate-like member that closes the space 62d1 of the case main body 62A from the lower side and has an opening 62d3 formed in the remaining pair of corners.
[0060]
The sound emission passage 62d for backloading in this modification guides the sound radiated to the back space of the electroacoustic transducer 60 from each opening 62d3 to each space 62d1, and to the front space via each opening 62d2. It comes to lead.
[0061]
Even in the case of adopting the configuration of this modification, it is possible to obtain the same effects as those of the above embodiment. In addition, according to the present modification, the backload sound emission passage 62d is formed in the case 62 so as to extend in the circumferential direction along the accommodation space C1, so that a relatively long sound path can be secured. This makes it possible to easily obtain a desired frequency characteristic.
[0062]
Next, a third modification of the above embodiment will be described.
[0063]
FIG. 9 is a plan view showing an electroacoustic transducer 70 according to this modification, and FIG. 10 is a perspective view showing the case 72 as a single product.
[0064]
The electroacoustic transducer 70 is configured according to the above-described embodiment with respect to the configuration other than the case 72 and the configurations of the peripheral wall surface 72a, the front sound emitting opening 72b, and the back sound emitting opening 72c. 10 is the same.
[0065]
In this modification, the backload sound emission passage 72d has eight groove-like recesses formed so as to extend in the vertical direction along the outer peripheral surface of the case 72 in the vicinity of each corner portion of the case 72. It is comprised by.
[0066]
Each of the groove-like recesses 72d forms a closed cross section with the groove-like recess 72d and the flange portion 102b of the case 102 of the mobile phone 100 when the electroacoustic transducer 70 is attached to the mobile phone 100. Thus, the sound radiated to the back space of the electroacoustic transducer 70 is guided to the front space.
[0067]
Even in the case of adopting the configuration of this modification, it is possible to obtain the same effects as those of the above embodiment. In addition, in the present modification, the backload sound emission passage is formed by the groove-shaped recessed portion 72d, so that the backload sound emission passage can be easily formed.
[0068]
In the above embodiment and each modified example, the terminal unit 18 is described as being provided on the inner peripheral side of the voice coil 14. However, even when the terminal unit 18 is provided on the outer peripheral side of the voice coil 14. The same effects as those of the above-described embodiment and the respective modifications can be obtained.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an electroacoustic transducer according to an embodiment of the present invention in a state in which the electroacoustic transducer is disposed so that its front surface is up. FIG. 2 is a plan view showing the electroacoustic transducer. A bottom view showing the electroacoustic transducer FIG. 4 is a side sectional view showing the electroacoustic transducer mounted on a mobile phone. FIG. 5 is an electroacoustic transducer according to a first modification of the embodiment. FIG. 6 is a perspective view showing a single case of the electroacoustic transducer according to the first modification. FIG. 7 is a plan view showing the electroacoustic transducer according to the second modification of the embodiment. FIG. 8 is a perspective view showing a single case of the electroacoustic transducer according to the second modification. FIG. 9 is a plan view showing the electroacoustic transducer according to the third modification of the embodiment. 3 is a perspective view showing an electroacoustic transducer case according to three modified examples as a single item.
10, 50, 60, 70 Electroacoustic transducer 12 Diaphragm 12a Outer peripheral edge flat part 12b Intermediate flat part 14 Voice coil 14a, 14b Coil terminal 16 Magnetic circuit unit 18 Terminal unit 20 Fixing ring 22, 52, 62, 72 Case 22a 52a, 62a, 72a Peripheral wall surfaces 22b, 52b, 62b, 72b Front sound emission openings 22c, 52c, 62c, 72c Back sound emission openings 22d, 52d, 62d Backload sound emission passage 22d1 Ring-shaped groove 22d2 Through hole 24 Base 24A Ring-shaped flat plate portion 24B Upward flange portion 24a Notch portion 26 Magnet 28 Yoke 28a Annular recess 30, 32 Terminal plate 34 Terminal substrate 36 Substrate support member 36a Notch portion 38 Large diameter coil springs 38a, 40a Upper end portion 40 Small diameter coil spring 62A Case main body 62B Cover 62d1 Space 62d2, 62d3 Opening 72d Sound emission passage for backloading (groove-shaped recess)
100 Mobile phone (external device)
102 Case 102a Sound emission hole 102b Flange 102c Case receiving part 104 Substrate 104a Opening 106, 108 Terminal plate C1 Housing space C2 Internal space

Claims (4)

An electrodynamic electroacoustic transducer configured to be attached to a substrate,
A diaphragm, a voice coil having one end fixed to the diaphragm, a magnetic circuit unit having a cylindrical magnetic gap for accommodating the other end of the voice coil, and the diaphragm, voice coil, and magnetic circuit A case for housing the unit,
A front sound emission opening for radiating sound from the diaphragm toward the front space of the electroacoustic transducer, and sound from the diaphragm toward the back space of the electroacoustic transducer. A rear sound emission opening for radiating and a backload sound emission passage for guiding sound radiated to the back space through the back sound emission opening to the front space are formed. An electroacoustic transducer characterized by that. 2. The electroacoustic transducer according to claim 1, wherein the backload sound emission passage is constituted by at least one through-hole penetrating the case. 3. The electroacoustic transducer according to claim 2, wherein the through hole is formed so as to extend in a circumferential direction of the magnetic circuit unit along the magnetic circuit unit. The electroacoustic transducer according to any one of claims 1 to 3, wherein an outer shape of the case is set to a substantially rectangular shape in a front view.

Images