Patent Application
20240373160
The present disclosure relates to an electroacoustic transducer and an electroacoustic transducer unit.
Japanese Patent No. 6325957 discloses an exciter. The exciter includes: a vibration body including a yoke and a magnet; a frame that houses the vibration body and supports the vibration body in a vibratable manner via a damper; a voice coil bobbin that is installed inside the frame and has one end attached to the frame and the other end extending to the vicinity of the vibration body; and a voice coil provided at the other end of the voice coil bobbin. Then, in the exciter, the vibration body vibrates according to an acoustic signal flowing through the voice coil, and vibration of the vibrator is transferred to the frame via the damper, so that it is possible to output a low-frequency sound via a transfer medium on which the frame is installed.
In the exciter, an opening is formed in the frame, and an outer peripheral surface of the one end of the voice coil bobbin is attached to a peripheral edge portion of the opening of the frame. A vibration member is provided in such a way as to cover an open portion of the one end of the voice coil bobbin. As a result, vibration of the voice coil is transferred to the vibration member via the voice coil bobbin, so that a high-frequency sound can be output from the vibration member toward the outside of the frame.
As described above, a vibration function for outputting a low-frequency sound and a function of outputting a high-frequency sound can be implemented by one driver in the related art described above, and thus, size reduction can be achieved compared to a multi-way speaker system.
However, in the related art described above, in an intermediate frequency band between a low-frequency sound and a high-frequency sound, the phase of sound from the transfer medium and the phase of sound from the vibration member are opposite to each other, and thus, a band in which a sound pressure greatly decreases (dip) occurs.
The present disclosure provides an electroacoustic transducer and an electroacoustic transducer unit capable of reproducing a high-quality sound by reducing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound while achieving size reduction.
A first aspect of the present disclosure is an electroacoustic transducer including: a drive unit that generates vibration, the drive unit being configured to, in response to an electric input signal, cause an action portion to generate an action force with respect to a reaction portion and cause the reaction portion to apply a reaction force to the action portion; a first diaphragm connected to one having a smaller mass out of the action portion and the reaction portion; and a second diaphragm having a larger area than the first diaphragm, the second diaphragm being connected to the first diaphragm via at least a first suspension, and being connected to one having a larger mass out of the action portion and the reaction portion via at least a second suspension, the second diaphragm being configured to radiate a sound to an external space on a front surface side when the drive portion generates vibration, wherein by providing a port that guides a component of at least a partial frequency band of a sound radiated from the first diaphragm in a direction opposite to a direction in which a front surface of the second diaphragm faces, to the external space on the front surface side of the second diaphragm, the electroacoustic transducer is configured such that a sound pressure of a synthesized sound in a vicinity of a crossover frequency of radiated sounds from the first diaphragm and the second diaphragm in when the drive unit generates vibration becomes equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm and the second diaphragm at the crossover frequency The “crossover frequency” in the first aspect refers to a frequency at which the radiated sound from the first diaphragm and the radiated sound from the second diaphragm are radiated at the same sound pressure (the same applies to the “crossover frequency” in the following specification).
According to the above configuration, the drive unit is configured to cause the action portion to generate the action force for the reaction portion in response to the electric input signal and cause the reaction portion to apply the reaction force to the action portion to generate vibration. The first diaphragm is connected to one having a smaller mass between the action portion and the reaction portion. Therefore, when the one having a smaller mass between the action portion and the reaction portion vibrates, the first diaphragm integrally vibrates. The first diaphragm has a smaller area than the second diaphragm, and a high-frequency sound can be reproduced from the first diaphragm.
The second diaphragm connected to the first diaphragm via at least the first suspension is connected to one having a larger mass between the action portion and the reaction portion via at least the second suspension. The second diaphragm has a larger area than the first diaphragm, and can radiate a sound to the external space on the front surface side, in a case in which the drive unit generates vibration. Here, in a case in which the drive unit generates vibration, vibration of the first diaphragm that integrally vibrates with one having a smaller mass between the action portion and the reaction portion is input to the second diaphragm via at least the first suspension, and a force acting from one having a smaller mass between the action portion and the reaction portion to one having a larger mass between the action portion and the reaction portion is input to the second diaphragm via at least the second suspension. As a result, in a case in which the drive unit generates vibration, vibration in a low-frequency band is input to the second diaphragm. Therefore, generation of a resonance sound that is likely to occur in a high-frequency band may be suppressed, and a low-frequency sound may be reproduced on the front surface side of the second diaphragm.
As described above, in the electroacoustic transducer of the present disclosure, since it is possible to vibrate two diaphragms, that is, the first diaphragm and the second diaphragm, with one drive unit, size reduction can be achieved. Moreover, as the port that guides the component of at least a partial frequency band of the sound radiated from the first diaphragm in the direction opposite to the direction in which the front surface of the second diaphragm faces, to the external space on the front surface side of the second diaphragm is provided, the electroacoustic transducer of the present disclosure is configured such that the sound pressure of the synthesized sound in the vicinity of the crossover frequency of the radiated sounds from the first diaphragm and the second diaphragm, in a case in which the drive unit generates vibration is equal to or higher than the sound pressure of the radiated sound from only one of the first diaphragm and the second diaphragm at the crossover frequency. As a result, it is possible to reproduce a high-quality sound by suppressing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound.
In a second aspect of the present disclosure, in the electroacoustic transducer according to the first aspect, a direction of a front surface of the first diaphragm may be matched with a direction of the front surface of the second diaphragm, and a sound may be radiated from the front surface of the first diaphragm to the external space on the front surface side of the second diaphragm, and the port may be configured to guide a component of a partial frequency band of sound radiated from a rear surface of the first diaphragm into a cavity on a rear surface side of the first diaphragm, to the external space on the front surface side of the second diaphragm.
According to the above configuration, the direction of the front surface of the first diaphragm is matched with the direction of the front surface of the second diaphragm, so that a sound can be radiated from the front surface of the first diaphragm to the external space on the front surface side of the second diaphragm. Meanwhile, the port guides a component of a partial frequency band of a sound radiated from the rear surface of the first diaphragm into the cavity on the rear surface side of the first diaphragm, to the external space on the front surface side of the second diaphragm. As a result, a sound from the rear surface of the first diaphragm is added to a frequency band of a dip in the sound pressure frequency characteristic, in a case in which a sound from the front surface of the first diaphragm and a sound from the front surface of the second diaphragm are synthesized, and a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound is suppressed as compared with the related technology (the above-described related art).
In a third aspect of the present disclosure, in the electroacoustic transducer according to the first aspect, a direction of a front surface of the first diaphragm may be opposite to a direction of the front surface of the second diaphragm, and a sound from a rear surface of the first diaphragm may not be radiated to the external space on the front surface side of the second diaphragm, and the port may be configured to guide a component of at least a partial frequency band of a sound radiated from the front surface of the first diaphragm in the direction opposite to the direction in which the front surface of the second diaphragm faces, to the external space on the front surface side of the second diaphragm.
According to the above configuration, the direction of the front surface of the first diaphragm is set to be opposite to the direction of the front surface of the second diaphragm. A sound from the rear surface of the first diaphragm is not radiated to the external space on the front surface side of the second diaphragm. The port guides a component of at least a partial frequency band of a sound radiated from the front surface of the first diaphragm in the direction opposite to the direction in which the front surface of the second diaphragm faces, to the external space on the front surface side of the second diaphragm. As a result, a sound from the electroacoustic transducer is a synthesized sound of a sound from the front surface of the second diaphragm, and at least a part of a sound from the front surface of the first diaphragm that faces a side opposite to a side that the front surface of the second diaphragm faces. Here, according to the above configuration, in an intermediate frequency band between a low-frequency sound and a high-frequency sound, the phase of a sound from the front surface of the second diaphragm and the phase of a sound from the front surface of the first diaphragm are not opposite to each other, as a result of which a decrease in sound pressure in the intermediate frequency band between the low-frequency sound and the high-frequency sound is suppressed as compared with a related technology (the above-described related art).
In a fourth aspect of the present disclosure, in the electroacoustic transducer according to the second aspect, a communication portion may be formed, that allows two spaces in the cavity on the rear surface side of the first diaphragm partitioned by the second suspension to communicate with each other.
According to the above configuration, a resonance frequency of a sound from the rear surface of the first diaphragm can be adjusted by effectively using not only air in one space that is in contact with the rear surface of the first diaphragm but also air in the other space of the two spaces and partitioned by the second suspension in the cavity on the rear surface side of the first diaphragm.
In a fifth aspect of the present disclosure, in the electroacoustic transducer according to the second or fourth aspect, a hole may be formed to penetrate through the second diaphragm, and the first diaphragm and an outlet of the port may be disposed inside the hole when viewed from a front surface side of the second diaphragm, and components including the drive unit, the first diaphragm, the first suspension, the second suspension, and the port may be unitized and disposed in such as not to protrude from the front surface side of the second diaphragm.
According to the above configuration, a sound from the front surface of the first diaphragm and a sound from the outlet of the port are output from the hole of the second diaphragm. In addition, since the components including the drive unit, the first diaphragm, the first suspension, the second suspension, and the port are unitized, the electroacoustic transducer can be easily manufactured by attaching the unitized components in such a way as to be continuous with the hole of the second diaphragm. Further, since the unitized components do not protrude from the front surface side of the second diaphragm, a simple form can be implemented.
A sixth aspect of the present disclosure is an electroacoustic transducer unit including: a housing that includes an attachment portion; a drive unit housed in the housing and generates vibration, the drive unit being configured to, in response to an electric input signal, cause an action portion to generate an action force with respect to a reaction portion and cause the reaction portion to apply a reaction force to the action portion; a first diaphragm provided inside the housing, the first diaphragm connected to one having a smaller mass out of the action portion and the reaction portion; a first suspension provided inside the housing, the first suspension connects the first diaphragm and the housing; and a second suspension provided inside the housing, the second suspension connects the housing and one having a larger mass out of the action portion and the reaction portion, wherein the electroacoustic transducer unit is used in an electroacoustic transducer in which a second diaphragm is configured to radiate a sound to an external space on a front surface side of the second diaphragm when the drive unit generates vibration in an attached state, in which the attachment portion of the housing is attached to the second diaphragm having a larger area than the first diaphragm, and wherein a port that can guide a component of at least a partial frequency band of a sound radiated from the first diaphragm in a direction opposite to a direction in which a front surface of the second diaphragm faces when the drive unit generates vibration in the attached state, to the external space on the front surface side of the second diaphragm is provided, and by providing the port, the electroacoustic transducer unit is configured such that a sound pressure of a synthesized sound in a vicinity of a crossover frequency of radiated sounds from the first diaphragm and the second diaphragm when the drive unit generates vibration in the attached state becomes equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm and the second diaphragm at the crossover frequency.
According to the above configuration, the drive unit housed in the housing is configured to cause the action portion to generate the action force for the reaction portion in response to the electric input signal and cause the reaction portion to apply the reaction force to the action portion to generate vibration. The first diaphragm provided inside the housing is connected to one having a smaller mass between the action portion and the reaction portion. Therefore, when the one having a smaller mass between the action portion and the reaction portion vibrates, the first diaphragm integrally vibrates. Further, inside the housing, the first suspension connects the first diaphragm and the housing, and the second suspension connects the housing and one having a larger mass between the action portion and the reaction portion. Further, the electroacoustic transducer unit of the present disclosure is used in the electroacoustic transducer in which the second diaphragm can radiate a sound to the external space on the front surface side of the second diaphragm in a case in which the drive unit generates vibration in the attached state in which the attachment portion of the housing is attached to the second diaphragm having a larger area than the first diaphragm. As described above, the electroacoustic transducer unit of the present disclosure can vibrate two diaphragms, that is, the first diaphragm and the second diaphragm.
Further, in the electroacoustic transducer unit of the present disclosure, the port can guide a component in at least a partial frequency band of a sound radiated from the first diaphragm in the direction opposite to the direction in which the front surface of the second diaphragm faces in a case in which the drive unit generates vibration in the attached state in which the attachment portion of the housing is attached to the second diaphragm, to the external space on the front surface side of the second diaphragm. As the port is provided, the electroacoustic transducer unit is configured such that the sound pressure of the synthesized sound in the vicinity of the crossover frequency of the radiated sounds from the first diaphragm and the second diaphragm, in a case in which the drive unit generates vibration in the attached state is equal to or higher than the sound pressure of the radiated sound from only one of the first diaphragm and the second diaphragm at the crossover frequency. As a result, it is possible to reproduce a high-quality sound by suppressing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound.
According to the above aspect, the electroacoustic transducer and the electroacoustic transducer of an embodiment of the present disclosure may reproduce a high-quality sound by reducing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound while achieving size reduction.
An electroacoustic transducer including an electroacoustic transducer unit according to a first exemplary embodiment of the present disclosure will be described with reference to
As illustrated in
A drive unit 16 is housed in the housing 14. Attachment of the drive unit 16 to the housing 14 will be described later. The drive unit 16 includes a magnetic circuit unit 20 as an action portion and a voice coil unit 18 as a reaction portion. In the present exemplary embodiment, the magnetic circuit unit 20 has a larger mass than the voice coil unit 18.
The voice coil unit 18 includes a voice coil bobbin 18A formed by bending a film in a cylindrical shape, and a voice coil main body 18B wound around a front portion of an outer peripheral surface of the voice coil bobbin 18A. In the drawing, a cross section of the voice coil bobbin 18A is indicated by a bold line for convenience, and a cross section of the voice coil main body 18B is illustrated in a simplified manner. Examples of a material of the voice coil bobbin 18A can include a resin material such as polyimide (PI) and a paper material such as kraft paper, and can further include a metal material such as an aluminum alloy. The voice coil main body 18B is made of an enameled wire obtained by coating an electric wire (for example, a copper wire) which is a linear conductor with an enameled film, and is wound around the voice coil bobbin 18A in two layers as an example.
The magnetic circuit unit 20 includes a yoke 22, a magnet 24, and a plate 26. The magnetic circuit unit 20 of the exemplary embodiment is an internal magnetic circuit unit that can achieve size reduction of the drive unit 16. The yoke 22 is a ferromagnetic body and is formed in a bottomed cylindrical shape, and includes a bottom portion 22A and a cylindrical portion 22B. The yoke 22 is disposed in such a way that a central axis direction thereof is along the front-rear direction (the direction of the arrow FR and an opposite direction thereof) and the bottom portion 22A is on the front side. A pedestal portion 22A1 is formed on the bottom portion 22A of the yoke 22 at a portion except for an outer peripheral portion on a rear surface side of the bottom portion 22A. The magnet 24 is formed in a disk shape and is fixed to a rear surface side of the pedestal portion 22A1 of the yoke 22. The magnet 24 is formed to have a smaller diameter than the pedestal portion 22A1 of the yoke 22. The plate 26 is a ferromagnetic body, is formed in a disk shape, and is fixed to a rear surface side of the magnet 24. The plate 26 is formed to have a larger diameter than the pedestal portion 22A1 of the yoke 22 and the magnet 24.
A magnetic gap 20A is formed between a rear portion of an inner peripheral surface of the cylindrical portion 22B of the yoke 22 and an outer peripheral surface of the plate 26. The voice coil main body 18B is inserted into the magnetic gap 20A together with the voice coil bobbin 18A. Then, the magnetic circuit unit 20 vibrates the voice coil unit 18 in the front-rear direction by using a Lorentz force based on an electric input signal to the voice coil main body 18B. That is, the drive unit 16 is configured to cause the magnetic circuit unit 20 to generate an action force for the voice coil unit 18 in response to an electric input signal, and cause the voice coil unit 18 to apply a reaction force to the magnetic circuit unit 20, thereby generating vibration. A dimension of the voice coil unit 18 in the front-rear direction applied to the electroacoustic transducer 10 of the exemplary embodiment is set to be large in consideration of vibration of the magnetic circuit unit 20 in the front-rear direction.
A first diaphragm 28 is connected to a rear end of the voice coil bobbin 18A of the voice coil unit 18. The first diaphragm 28 is provided inside the housing 14, and a cavity S2 is formed on a rear surface 28B side of the first diaphragm 28. A front surface 28A of the first diaphragm 28 is opposite to the side of the first diaphragm 28 that is adjacent to the voice coil bobbin 18A (in other words, a side facing the rear wall portion 14R of the housing 14). The direction of the front surface 28A of the first diaphragm 28 is set to be opposite to the front side (see the direction of the arrow FR) of the electroacoustic transducer 10. In the drawing, for convenience, the first diaphragm 28 is schematically illustrated in a simplified manner. In the drawing, a direction in which a sound from the first diaphragm 28 propagates is simplified and indicated by a white arrow a.
As an example, a paper cone (a cone made of a material containing pulp fibers or the like) can be applied as the first diaphragm 28. As a material of the first diaphragm 28, for example, a papermaking material such as pulp fibers or a resin material such as polypropylene (PP), polyimide (PI), polyetherimide (PEI), or polycarbonate (PC) can be applied, and a metal material such as an aluminum alloy can also be applied. Further, a film-like diaphragm (a diaphragm having a small thickness) can be applied as the first diaphragm 28.
The first diaphragm 28 and the housing 14 are connected by a first suspension 30. The first suspension 30 is provided inside the housing 14 and formed in an annular shape in front view, and is joined to an outer peripheral portion of the first diaphragm 28 and a portion on an inner surface side of the housing 14. The first suspension 30 is an element that can be grasped as a mechanical filter having a function of passing low-frequency vibration and blocking high-frequency vibration.
Examples of a member corresponding to the first suspension 30 include a known edge. A material and a shape of the edge are a material and a shape that can acoustically block a space in front of and behind the first diaphragm 28. See
As illustrated in
As illustrated in
The second diaphragm 38 has a larger area than the first diaphragm 28, and can vibrate in the front-rear direction in a wider range than the first diaphragm 28. Examples of the second diaphragm 38 include a table, a dashboard of a vehicle, and an A-pillar.
In summary, the electroacoustic transducer unit 12 is used in the electroacoustic transducer 10 in which the second diaphragm 38 can radiate a sound to the external space S1 on the front surface 38A side in a case in which the drive unit 16 generates vibration in an attached state where the attachment portion 14A of the housing 14 is attached to the second diaphragm 38. In the drawing, a propagation direction of a sound from the front surface 38A of the second diaphragm 38 is simplified and indicated by a white arrow b.
Meanwhile, the electroacoustic transducer unit 12 has a port (also referred to as “sound path”) 36 capable of guiding a component of at least a partial frequency band of a sound radiated from the front surface 28A of the first diaphragm 28 in a direction opposite to a direction in which the front surface 38A of the second diaphragm 38 faces to the external space S1 on the front surface 38A side of the second diaphragm 38, in a case in which the drive unit 16 generates vibration in the attached state where the attachment portion 14A of the housing 14 is attached to the second diaphragm 38. Further, as the port 36 is provided, the electroacoustic transducer unit 12 is configured such that, a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from the first diaphragm 28 and the second diaphragm 38, in a case in which the drive unit 16 generates vibration in the attached state, in which the attachment portion 14A of the housing 14 is attached to the second diaphragm 38, is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 38 at the crossover frequency.
In other words, as the port 36 that guides the component of at least a partial frequency band of the sound radiated from the front surface 28A of the first diaphragm 28 in the direction opposite to the direction in which the front surface 38A of the second diaphragm 38 faces to the external space S1 on the front surface 38A side of the second diaphragm 38 is provided, the electroacoustic transducer 10 is configured such that the sound pressure of the synthesized sound in the vicinity of the crossover frequency of the radiated sounds from the first diaphragm 28 and the second diaphragm 38, in a case in which the drive unit 16 generates vibration is equal to or higher than the sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 38 at the crossover frequency.
In the exemplary embodiment, as an example, the port 36 is implemented by a through-hole formed at a portion of the peripheral wall portion 14S on a rear end portion side and having a circumferential direction of the peripheral wall portion 14S as a longitudinal direction. A large number of ports 36 are formed in such a way as to be arranged in the circumferential direction of the peripheral wall portion 14S, and are set, in such a way as to guide all radiated sounds from the front surface 28A of the first diaphragm 28 to the external space S1 on the front surface 38A side of the second diaphragm 38.
Here, simulation for a sound pressure frequency characteristic of the electroacoustic transducer 10 will be supplementary described with reference to
In
Vibration speed characteristics of the first diaphragm 28 and the second diaphragm 38 can be obtained from an electric circuit (equivalent circuit) created based on the vibration model illustrated in
Next, actions and effects of the first exemplary embodiment will be described.
In the electroacoustic transducer 10 illustrated in
The second diaphragm 38 to which the first diaphragm 28 is connected via at least the first suspension 30 is connected to the magnetic circuit unit 20 having a larger mass than the voice coil unit 18 via at least the second suspension 32. The second diaphragm 38 has a larger area than the first diaphragm 28, and can radiate a sound to the external space S1 on the front surface 38A side in a case in which the drive unit 16 generates vibration. Here, in a case in which the drive unit 16 generates vibration, vibration of the first diaphragm 28 that vibrates integrally with the voice coil unit 18 is input to the second diaphragm 38 via the first suspension 30 or the like, and a reaction force applied from the voice coil unit 18 to the magnetic circuit unit 20 is input to the second diaphragm 38 via the second suspension 32 or the like. As a result, in a case in which the drive unit 16 generates vibration, vibration in a low-frequency band is input to the second diaphragm 38. Therefore, generation of a resonance sound that is likely to occur in a high-frequency band is suppressed, and a low-frequency sound can be reproduced on the front surface 38A side of the second diaphragm 38.
As described above, in the electroacoustic transducer according to the exemplary embodiment, since it is possible to vibrate two diaphragms, that is, the first diaphragm 28 and the second diaphragm 38, with one drive unit 16, size reduction (space saving) and cost reduction can be achieved. Further, since the electroacoustic transducer unit 12 includes the attachment portion 14A for attachment to another member, the electroacoustic transducer unit 12 can be attached to various members, and various members can be used as the second diaphragm.
Moreover, as the port 36 that guides the component of at least a partial frequency band of the sound radiated from the first diaphragm 28 in the direction opposite to the direction in which the front surface 38A of the second diaphragm 38 faces to the external space S1 on the front surface 38A side of the second diaphragm 38 is provided, the electroacoustic transducer 10 of the exemplary embodiment is configured such that the sound pressure of the synthesized sound in the vicinity of the crossover frequency of the radiated sounds from the first diaphragm 28 and the second diaphragm 38, in a case in which the drive unit 16 generates vibration is equal to or higher than the sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 38 at the crossover frequency. As a result, it is possible to reproduce a high-quality sound by suppressing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound.
More specifically, in the exemplary embodiment, the direction of the front surface 28A of the first diaphragm 28 is set to be opposite to the direction of the front surface 38A of the second diaphragm 38. A sound from the rear surface 28B of the first diaphragm 28 is not radiated to the external space S1 on the front surface 38A side of the second diaphragm 38. The above-described port 36 guides a component of at least a partial frequency band of a sound radiated from the front surface 28A of the first diaphragm 28 in the direction opposite to the direction in which the front surface 38A of the second diaphragm 38 faces to the external space S1 on the front surface 38A side of the second diaphragm 38.
As a result, a sound from the electroacoustic transducer 10 is a synthesized sound of a sound from the front surface 38A of the second diaphragm 38 and at least a part of a sound from the front surface 28A of the first diaphragm 28 that faces a side opposite to a side that the front surface 38A of the second diaphragm 38 faces. Here, in an intermediate frequency band between a low-frequency sound and a high-frequency sound, the phase of a sound from the front surface 38A of the second diaphragm 38 and the phase of a sound from the front surface 28A of the first diaphragm 28 are not opposite to each other, as a result of which a decrease in sound pressure in the intermediate frequency band between the low-frequency sound and the high-frequency sound is suppressed as compared with a conventional technology (the above-described related art).
This point will be supplementary described with reference to
In the comparative example, an exciter with a diaphragm is installed on a flat plate, and the front and rear of the electroacoustic transducer unit 12 in the electroacoustic transducer 10 illustrated in
In the comparative example, a high-frequency sound is reproduced by the vibration of the diaphragm of the exciter (see the dotted line in
On the other hand, in the electroacoustic transducer 10 of the exemplary embodiment, a sound from the front surface 38A of the second diaphragm 38 and at least a part of a sound from the front surface 28A of the first diaphragm 28 that faces the side opposite to the side that the front surface 38A of the second diaphragm 38 faces are synthesized and radiated in such a way that the phase of a sound from the first diaphragm 28 and the phase of a sound from the second diaphragm 38 illustrated in
As described above, according to the exemplary embodiment, it is possible to reproduce a high-quality sound by suppressing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound while achieving size reduction.
Next, an electroacoustic transducer including an electroacoustic transducer unit according to a second exemplary embodiment of the present disclosure will be described with reference to
The electroacoustic transducer unit 42 includes a housing 44 instead of the housing 14 (see
An attachment portion 44A for attachment to another member is provided on the housing 44. As an example, the attachment portion 44A projects in a flange shape in such a way as to be orthogonal to the front-rear direction from a portion where the front wall portion 44F and the peripheral wall portion 14S intersect. The housing 44 is disposed on a rear surface 41B side of a second diaphragm 41, and the attachment portion 44A of the housing 44 is attached to the second diaphragm 41. The second diaphragm 41 has a larger area than the first diaphragm 28. As the attachment portion 44A of the housing 44 is attached to the second diaphragm 41, the first diaphragm 28 is connected to the second diaphragm 41 via the first suspension 30 and the housing 44, and a magnetic circuit unit 20 is connected to the second diaphragm 41 via the second suspension 32 and the housing 44. In a case in which a drive unit 16 generates vibration, the second diaphragm 41 can radiate a sound into an external space S1 on a front surface 41A side (see an arrow b).
The electroacoustic transducer 40 is configured by attaching the attachment portion 44A of the housing 44 in the electroacoustic transducer unit 42 to the second diaphragm 41 in the above-described state. The electroacoustic transducer 40 is configured such that the direction of a front surface 28A of the first diaphragm 28 is set to be opposite to the direction of the front surface 41A of the second diaphragm 41, and a sound from the rear surface 28B of the first diaphragm 28 is not radiated to the external space S1 on the front surface 41A side of the second diaphragm 41.
On the other hand, a hole 46H is formed to penetrate through the rear wall portion 44R of the housing 44 in the electroacoustic transducer unit 42 in such a way as to correspond to the central portion of the front surface 28A of the first diaphragm 28 A short cylindrical horn attachment portion 44Z protruding rearward is formed around the hole 46H on a rear surface side of the rear wall portion 44R. One end portion of a horn 46D included as a part of the electroacoustic transducer unit 42 is attached to an outer peripheral portion of the horn attachment portion 44Z. The horn 46D is formed in a substantially J shape. A front portion of the horn 46D is formed in a shape gradually increasing in diameter toward an end portion side of the second diaphragm 41. A front end portion of the horn 46D is connected to a hole 41H formed in the second diaphragm 41 by press-fitting, for example. An attachment portion for attachment to the second diaphragm 41 may be separately provided at a portion on a front end portion side of the horn 46D. The hole 41H is formed to penetrate through the second diaphragm 41 in the vicinity of a portion where the electroacoustic transducer unit 42 is installed.
The hole 46H and the horn 46D of the housing 44 constitute a port 46 of the present exemplary embodiment. The port 46 is configured to guide a component of at least a partial frequency band (for example, the entire frequency band) of a sound radiated from the front surface 28A of the first diaphragm 28 in a direction opposite to a direction in which the front surface 41A of the second diaphragm 41 faces to the external space S1 on the front surface 41A side of the second diaphragm 41. As the port 46 is provided, the electroacoustic transducer 40 is configured such that a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from the first diaphragm 28 and the second diaphragm 41, in a case in which the drive unit 16 generates vibration is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 41 at the crossover frequency.
The configuration of the second exemplary embodiment described above can also provide substantially similar actions and effects to those of the first exemplary embodiment described above. In the exemplary embodiment, it is not necessary to provide a portion protruding forward from the second diaphragm 41, so that a simple form can be implemented.
Next, an electroacoustic transducer including an electroacoustic transducer unit according to the third exemplary embodiment of the present disclosure will be described with reference to
The electroacoustic transducer unit 52 includes a housing 54 instead of the housing 14 (see
An attachment portion 54A for attachment to another member is provided on the housing 54. As an example, the attachment portion 54A projects in a flange shape in such a way as to be orthogonal to the front-rear direction from a portion where the rear wall portion 54R and the peripheral wall portion 54S intersect. The housing 54 is disposed on a front surface 38A side of a second diaphragm 38, and the attachment portion 54A of the housing 54 is attached to the second diaphragm 38. Therefore, the electroacoustic transducer 50 is configured by attaching the electroacoustic transducer unit 52 to the second diaphragm 38.
When viewed with reference to the rear wall portion 54R, the front and rear of components inside the housing 54 are arranged in an opposite direction from those of the components inside the housing 14 (see
The electroacoustic transducer 50 is configured such that the direction of a front surface 28A of a first diaphragm 28 is matched with the direction of the front surface 38A of the second diaphragm 38, so that a sound can be radiated from the front surface 28A of the first diaphragm 28 to an external space S1 on the front surface 38A side of the second diaphragm 38. A first suspension 30 connects an outer peripheral portion of the first diaphragm 28 and the housing 54. Accordingly, in the electroacoustic transducer 50, the first diaphragm 28 is connected to the second diaphragm 38 via the first suspension 30 and the housing 54. A drive unit 16 is disposed on a rear surface 28B side of the first diaphragm 28.
The second suspension 33 connects an outer peripheral portion of a magnetic circuit unit 20 and the housing 54. Accordingly, in the electroacoustic transducer 50, the magnetic circuit unit 20 is connected to the second diaphragm 38 via the second suspension 33 and the housing 54. The second diaphragm 38 can radiate a sound to the external space S1 on the front surface 38A side in a case in which the drive unit 16 generates vibration.
A port 56 is continuously provided at a rear end portion of the peripheral wall portion 54S of the housing 54. As an example, the port 56 is formed by a through-hole 56H formed at the rear end portion of the peripheral wall portion 54S of the housing 54, and a cylindrical duct 56D formed continuously with the through-hole 56H and extending in a direction orthogonal to the front-rear direction.
The port 56 is configured to guide a component of a partial frequency band of a sound radiated from the rear surface 28B of the first diaphragm 28 into the cavity S2 on the rear surface 28B side of the first diaphragm 28 (in other words, a sound radiated from the rear surface 28B of the first diaphragm 28 in a direction opposite to a direction in which the front surface 38A of the second diaphragm 38 faces) to the external space S1 on the front surface 38A side of the second diaphragm 38.
More specifically, the port 56 illustrated in
Next, actions and effects of the third exemplary embodiment will be described.
In the electroacoustic transducer 50 illustrated in
Further, the port 56 provided continuously with the housing 54 guides a component of a partial frequency band of a sound radiated from the rear surface 28B of the first diaphragm 28 into the cavity S2 on the rear surface 28B side of the first diaphragm 28 to the external space S1 on the front surface 38A side of the second diaphragm 38. As a result, a sound from the rear surface 28B of the first diaphragm 28 is added to a frequency band of a dip in the sound pressure frequency characteristic, in a case in which a sound from the front surface 28A of the first diaphragm 28 and a sound from the front surface 38A of the second diaphragm 38 are synthesized, and a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound is suppressed as compared with the conventional technology (the above-described related art).
This point will be supplementary described with reference to
As illustrated in
Further, the communication holes 33H (see
As described above, according to the third exemplary embodiment, it is also possible to reproduce a high-quality sound by suppressing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound while achieving size reduction.
A spider (also referred to as a “damper”) 34 illustrated in
Next, an electroacoustic transducer including an electroacoustic transducer unit according to a fourth exemplary embodiment of the present disclosure will be described with reference to
The electroacoustic transducer unit 62 includes a housing 64 instead of the housing 54 (see
Meanwhile, a second diaphragm 61 to which the electroacoustic transducer unit 62 is attached has a larger area than a first diaphragm 28. A hole 61H is formed to penetrate through the second diaphragm 61. The attachment portion 64A of the housing 64 is disposed on a rear surface 61B side of the second diaphragm 61 and around the hole 61H, and is attached to the second diaphragm 61. The electroacoustic transducer 60 is configured by attaching the electroacoustic transducer unit 62 to the second diaphragm 61. The second diaphragm 61 can radiate a sound to an external space S1 on a front surface 61A side in a case in which a drive unit 16 generates vibration.
Components inside the housing 64 are substantially similar to the components inside the housing 54 (see
A second suspension 33 connects an outer peripheral portion of a magnetic circuit unit 20 and the cylindrical wall portion 64B of the housing 64. Accordingly, in the electroacoustic transducer 60, the magnetic circuit unit 20 is connected to the second diaphragm 61 via the second suspension 33 and the housing 64.
A port 66 is continuously provided at a part of the cylindrical wall portion 64B of the housing 64. As an example, the port 66 is formed by a through-hole 66H formed at a rear end portion of the cylindrical wall portion 64B of the housing 64 and a duct portion 66D formed continuously with the through-hole 66H. The duct portion 66D is formed in such a way that an internal space of the duct portion 66D extends in the front-rear direction. A rear end portion of the duct portion 66D is a closed portion 66D1, and a front end portion of the duct portion 66D is an outlet 66E of the port 66. As an example, a part of the duct portion 66D is implemented by a part of the cylindrical wall portion 64B.
The port 66 is configured to guide a component of a partial frequency band (more specifically, a sound in an intermediate frequency band between a low-frequency sound and a high-frequency sound) of a sound radiated from the rear surface 28B of the first diaphragm 28 into a cavity S2 on the rear surface 28B side of the first diaphragm 28 (in other words, a sound radiated from the rear surface 28B of the first diaphragm 28 in a direction opposite to a direction in which the front surface 61A of the second diaphragm 61 faces) to the external space S1 on the front surface 61A side of the second diaphragm 61. As the port 66 is provided, the electroacoustic transducer 60 is configured such that a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from the first diaphragm 28 and the second diaphragm 61, in a case in which the drive unit 16 generates vibration is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 61 at the crossover frequency.
When viewed from the front surface 61A side of the second diaphragm 61, the first diaphragm 28 and the outlet 66E of the port 66 are disposed inside the hole 61H. Further, the electroacoustic transducer unit 62 in which components including the drive unit 16, the first diaphragm 28, the first suspension 30, the second suspension 33, and the port 66 are unitized is disposed in such a way as not to protrude from the front surface 61A of the second diaphragm 61.
Next, actions and effects of the fourth exemplary embodiment will be described.
In the electroacoustic transducer 60 illustrated in
In the fourth exemplary embodiment, the electroacoustic transducer 60 can be easily manufactured by attaching the electroacoustic transducer unit 62 in such a way as to be continuous with the hole 61H of the second diaphragm 61, and the electroacoustic transducer unit 62 does not protrude toward the front surface 61A with respect to the second diaphragm 61, so that a simple form can be implemented.
Next, an electroacoustic transducer including an electroacoustic transducer unit according to a fifth exemplary embodiment of the present disclosure will be described with reference to
The electroacoustic transducer unit 72 includes a housing 74 instead of the housing 54 (see
A port 76 is continuously provided at a portion on a rear side of a portion to which a first suspension 30 is attached and a portion on a front side of a portion to which the second suspension 33 is attached in the peripheral wall portion 74S of the housing 74. As an example, the port 76 is formed by a through-hole 76H formed in the peripheral wall portion 74S of the housing 74, and a cylindrical duct 76D formed continuously with the through-hole 76H and extending in a direction orthogonal to the front-rear direction.
The port 76 is configured to guide a component of a partial frequency band (more specifically, a sound in an intermediate frequency band between a low-frequency sound and a high-frequency sound) of a sound radiated from a rear surface 28B of a first diaphragm 28 into a cavity S2 on a rear surface 28B side of the first diaphragm 28 (in other words, a sound radiated from the rear surface 28B of the first diaphragm 28 in a direction opposite to a direction in which a front surface 38A of the second diaphragm 38 faces) to the external space S1 on a front surface 38A side of the second diaphragm 38. As the port 76 is provided, the electroacoustic transducer 70 is configured such that a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from the first diaphragm 28 and the second diaphragm 38, in a case in which the drive unit 16 generates vibration is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 38 at the crossover frequency.
The configuration of the fifth exemplary embodiment described above can also provide substantially similar actions and effects to those of the third exemplary embodiment described above.
Next, an electroacoustic transducer including an electroacoustic transducer unit according to a sixth exemplary embodiment of the present disclosure will be described with reference to
A second diaphragm 81 according to the present exemplary embodiment illustrated in
The electroacoustic transducer unit 82 of the exemplary embodiment includes a housing 84 (see
The port 86 is continuously provided at a portion on a rear side of a portion to which a first suspension 30 is attached and a portion on a front side of a portion to which a second suspension 33 is attached in the peripheral wall portion 84S of the housing 84. As an example, the port 86 is formed by a through-hole 86H formed in the peripheral wall portion 84S of the housing 84 and a cylindrical duct 86D formed continuously with the through-hole 86H. The duct 86D extends from the through-hole 86H in a direction orthogonal to the front-rear direction, and a distal end portion of the duct 86D in the extension direction is closed and a front portion on a distal end portion side in the extension direction is an outlet 86E of the port 86.
The port 86 is configured to guide a component of a partial frequency band (more specifically, a sound in an intermediate frequency band between a low-frequency sound and a high-frequency sound) of a sound radiated from a rear surface 28B of a first diaphragm 28 into a cavity S2 on a rear surface 28B side of the first diaphragm 28 (in other words, a sound radiated from the rear surface 28B of the first diaphragm 28 in a direction opposite to a direction in which a front surface 81A of the second diaphragm 81 faces) to an external space S1 on a front surface 81A side of the second diaphragm 81. As the port 86 is provided, the electroacoustic transducer 80 is configured such that a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from the first diaphragm 28 and the second diaphragm 81, in a case in which a drive unit 16 generates vibration is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 81 at the crossover frequency.
When viewed from the front surface 81A side of the second diaphragm 81, the first diaphragm 28 and the outlet 86E of the port 86 are disposed inside the hole 81H of the second diaphragm 81. Further, the electroacoustic transducer unit 82 in which components including the drive unit 16, the first diaphragm 28, the first suspension 30, the second suspension 33, and the port 86 are unitized is disposed in such a way as not to protrude from the front surface 81A of the second diaphragm 81.
The configuration of the sixth exemplary embodiment described above can also provide substantially similar actions and effects to those of the fourth exemplary embodiment described above.
Next, an electroacoustic transducer including an electroacoustic transducer unit according to a seventh exemplary embodiment of the present disclosure will be described with reference to
The second suspension 98 of the electroacoustic transducer unit 92 is substantially similar to the second suspension 33 of the fifth exemplary embodiment (see
The port 96 is formed by a through-hole 176H formed in a peripheral wall portion 174S of the housing 94, and a cylindrical duct 96D formed continuously with the through-hole 176H and extending in a direction orthogonal to the front-rear direction. The port 96 has a configuration similar to that of the port 76 of the fifth exemplary embodiment except that the length of the port 96 is set in such a way as to obtain an effect substantially similar to that of the fifth exemplary embodiment, and the port 96 has a length larger than that of the port 76 of the fifth exemplary embodiment. As the port 96 is provided, the electroacoustic transducer 90 is configured such that a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from a first diaphragm 28 and a second diaphragm 38, in a case in which a drive unit 16 generates vibration is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 38 at the crossover frequency.
Here, the configuration of the present exemplary embodiment will be supplementary described. As in the exemplary embodiment, in a case in which the second suspension 98 has no air permeability, the port 96 needs to be provided in such a way as to communicate with an internal space between a first suspension 30 and the second suspension 98. In such a configuration, the volume of a cavity adjacent to the port is reduced as compared with a case where the second suspension 33 (see
For this reason, in the configuration in which the second suspension has no air permeability, the air spring of the cavity adjacent to the port becomes hard, and the resonance frequency of the sound from the port tends to be high, as compared with the configuration in which the second suspension has air permeability. Therefore, it is necessary to decrease a passage cross-sectional area of the port, increase the length of the port, or decrease the passage cross-sectional area of the port to increase the length of the port as compared with a case where the second suspension has air permeability, in order to set the resonance frequency to a desired frequency. From this point of view, in the seventh exemplary embodiment, the port 96 is set to be longer than the port 76 (see
The configuration of the seventh exemplary embodiment described above can also provide substantially similar actions and effects to those of the fifth exemplary embodiment described above.
As a modification of the seventh exemplary embodiment, a port having a smaller passage cross-sectional area than the port 76 (see
Next, an electroacoustic transducer including an electroacoustic transducer unit according to an eighth exemplary embodiment of the present disclosure will be described with reference to
A second diaphragm 101 according to the present exemplary embodiment illustrated in
A housing 104 of the electroacoustic transducer unit 102 has a similar configuration to the housing 84 of the sixth exemplary embodiment except that the port 106 is provided instead of the port 86 (see
The port 106 is formed by a through-hole 186H formed in a peripheral wall portion 184S of the housing 104 and a duct 106D formed continuously with the through-hole 186H. The duct 106D extends from the through-hole 186H in a direction orthogonal to the front-rear direction, and a distal end portion of the duct 106D in the extension direction is closed and a front portion on a distal end portion side in the extension direction is an outlet 106E of the port 106. The port 106 has a configuration similar to that of the port 86 of the sixth exemplary embodiment, except that the length of the port 106 is set in such a way as to obtain an effect substantially similar to that of the sixth exemplary embodiment, and the port 106 has a length larger than that of the port 86 (see
The configuration of the eighth exemplary embodiment described above can also provide substantially similar actions and effects to those of the sixth exemplary embodiment described above.
As a modification of the eighth exemplary embodiment, a port having a smaller passage cross-sectional area than the port 86 (see
Next, an electroacoustic transducer including an electroacoustic transducer unit according to the ninth exemplary embodiment of the present disclosure will be described with reference to
A first diaphragm 28 is formed in an annular shape in front view, and has a conical shape in which a front surface is gradually recessed toward a central portion side. A dome-shaped center cap 27 is joined to the central portion side of a front surface of the first diaphragm 28. The first first-suspension 120 made of an elastic material such as rubber is joined to an outer peripheral portion 28D of the first diaphragm 28 over the entire circumference. The first first-suspension 120 is referred to as an edge, is formed in an annular shape in front view, and is joined to an annular attachment portion 54B on a front end portion side of a housing 54 over the entire circumference.
As an example, the housing 54 includes a frame 54X forming a front portion and a middle portion of the housing 54 in the front-rear direction, and a case 54Y attached to a rear end portion of the frame 54X and forming a rear portion of the housing 54. A shelf-shaped portion 54Z extending inward in a radial direction of the frame 54X is formed at a rear end portion of the frame 54X. An outer peripheral surface of a cylindrical inner cylinder member 55 is fixed to an inner peripheral surface of the middle portion of the housing 54 in the front-rear direction in a state of being in contact with the entire circumference. Furthermore, a front surface of the shelf-shaped portion 54Z and a rear end surface of the inner cylinder member 55 are slightly separated in the front-rear direction.
Meanwhile, a short cylindrical inner peripheral end portion 28C bent rearward is provided at a central portion of the first diaphragm 28. The inner peripheral end portion 28C is joined to an outer peripheral portion on a front end portion side of a voice coil bobbin 18A. An inner peripheral portion of the second first-suspension 122 is joined to the inner peripheral end portion 28C of the first diaphragm 28. The second first-suspension 122 is a member substantially similar to the spider 34 illustrated in
As described above, the first first-suspension 120 and the second first-suspension 122 are disposed at an interval in the front-rear direction (a vibration direction of the first diaphragm 28 and a voice coil unit 18). The first diaphragm 28 is connected to a second diaphragm 38 via the first first-suspension 120 and the housing 54, and is connected to the second diaphragm 38 via a plurality of members including the second first-suspension 122 and the housing 54.
An inner peripheral portion of the first second-suspension 124 is joined to a front end surface portion of a cylindrical portion 22B of a yoke 22 over the entire circumference. The first second-suspension 124 is formed in an annular shape in front view, has a communication hole 124H as a communication portion formed to penetrate through the first second-suspension 124, and is a member substantially similar to the second suspension 33 illustrated in
An inner peripheral portion of the second second-suspension 126 is joined to an outer peripheral portion of a rear surface of the yoke 22 over the entire circumference. The second second-suspension 126 is formed in an annular shape in front view, has a communication hole 126H as a communication portion formed to penetrate through the second second-suspension 126, and is a member substantially similar to the first second-suspension 124. An outer peripheral portion of the second second-suspension 126 is disposed between a rear surface of the inner cylinder member 55 and the front surface of the shelf-shaped portion 54Z of the housing 54 and is joined to the housing 54.
As described above, the first second-suspension 124 and the second second-suspension 126 are disposed at an interval in the front-rear direction (a vibration direction of a magnetic circuit unit 20). The magnetic circuit unit 20 is connected to the second diaphragm 38 via the first second-suspension 124, the inner cylinder member 55, and the housing 54, and is connected to the second diaphragm 38 via the second second-suspension 126 and the housing 54.
According to the configuration of the ninth exemplary embodiment described above, it is also possible to reproduce a high-quality sound by suppressing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound by substantially similar actions to those of the third exemplary embodiment described above while achieving size reduction.
In the ninth exemplary embodiment, the first first-suspension 120 and the second first-suspension 122 are provided at an interval in the vibration direction of the first diaphragm 28 and the voice coil unit 18, so that the first diaphragm 28 and the voice coil unit 18 can vibrate in the front-rear direction basically without rolling (swinging). Since the first second-suspension 124 and the second second-suspension 126 are provided at an interval in the vibration direction of the magnetic circuit unit 20, the magnetic circuit unit 20 can basically vibrate in the front-rear direction without rolling. In this way, as rolling of the first diaphragm 28, the voice coil unit 18, and the magnetic circuit unit 20 is suppressed, it is possible to prevent or effectively suppress a portion of the voice coil unit 18 disposed in a magnetic gap 20A of the magnetic circuit unit 20 from coming into contact with the magnetic circuit unit 20.
For example, there may be a case where a plurality of first suspensions and a plurality of second suspensions cannot be provided due to space restrictions or the like, such as a case where the length of the electroacoustic transducer unit in the front-rear direction needs to be decreased. In such a case, the voice coil unit (18) and the magnetic circuit unit (20) are assumed to roll, and it is sufficient if the width of the magnetic gap (20A) of the magnetic circuit unit (20) is set large so that a portion of the voice coil unit (18) disposed in the magnetic gap (20A) of the magnetic circuit unit (20) does not come into contact with the magnetic circuit unit (20) even when the assumed rolling occurs. However, in this case, it is disadvantageous in terms of a driving force.
Next, an electroacoustic transducer according to a tenth exemplary embodiment of the present disclosure will be described with reference to
As illustrated in
A drive unit 16 is disposed inside the first suspension 132. A second suspension 134 is disposed on a rear side of the drive unit 16. The second suspension 134 is formed in a cylindrical shape and a bellows shape, and has a smaller diameter and a smaller length in the cylinder axis direction than the first suspension 132. The second suspension 134 is disposed in such a way that the cylinder axis direction is the front-rear direction, and the center axis (not illustrated) of the second suspension 134 is aligned with that of the first suspension 132. An opening end portion of the second suspension 134 on one side in the cylinder axis direction is joined to an outer peripheral portion of a rear surface 22R of a yoke 22. An opening end portion of the second suspension 134 on the other side in the cylinder axis direction is joined to the front surface 138A of the second diaphragm 138. That is, a magnetic circuit unit 20 is connected to the second diaphragm 138 via the second suspension 134.
A communication hole 134H for allowing a space on an inner side of the second suspension 134 and a space on an outer side of the second suspension 134 to communicate with each other is formed to penetrate through the second suspension 134. The communication hole 134H allows two spaces S31 and S32 partitioned by the second suspension 134 to communicate with each other in a cavity S3 on a rear surface 28B side of the first diaphragm 28. A plurality of communication holes 134H are formed in such a way as to be arranged in a circumferential direction of the second suspension 134.
The second diaphragm 138 has a larger area than the first diaphragm 28, and can radiate a sound to an external space S1 on a front surface 138A side in a case in which the drive unit 16 generates vibration. In the second diaphragm 138, a first hole 138C is formed to penetrate through a portion inside the second suspension 134 in front view, and a second hole 138D is formed to penetrate through a portion outside the first suspension 132 in front view. One end portion of a port 136 is connected to the first hole 138C, and the other end portion of the port 136 is connected to the second hole 138D. The port 136 is bent in a substantially C shape.
The port 136 is configured to guide a component of a partial frequency band (more specifically, a sound in an intermediate frequency band between a low-frequency sound and a high-frequency sound) of a sound radiated from the rear surface 28B of the first diaphragm 28 into the cavity S3 on the rear surface 28B side of the first diaphragm 28 (in other words, a sound radiated from the rear surface 28B of the first diaphragm 28 in a direction opposite to a direction in which the front surface 138A of the second diaphragm 138 faces) to the external space S1 on the front surface 138A side of the second diaphragm 138. As the port 136 is provided, the electroacoustic transducer 130 is configured such that a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from the first diaphragm 28 and the second diaphragm 138, in a case in which the drive unit 16 generates vibration is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 138 at the crossover frequency.
According to the configuration of the tenth exemplary embodiment described above, it is also possible to reproduce a high-quality sound by suppressing a decrease in sound pressure in an intermediate frequency band between a low-frequency sound and a high-frequency sound by substantially similar actions to those of the third exemplary embodiment described above while achieving size reduction.
As a modification of the tenth exemplary embodiment, a configuration in which, instead of the first hole (138C) in the second diaphragm (138), the first hole is formed to penetrate through a portion of the second diaphragm (138) outside the second suspension (134) and inside the first suspension (132) in front view, and the first hole and the second hole (138D) are connected by a port, can also be adopted. Furthermore, as a further modification of such a modification, a configuration in which the communication hole (134H) is not provided in the second suspension (134) may be adopted. In these modifications, it goes without saying that the dimension of the port is set in such a way as to obtain substantially similar effects to those of the tenth exemplary embodiment.
Next, an electroacoustic transducer according to an eleventh exemplary embodiment of the present disclosure will be described with reference to
The driver unit 142 has a configuration substantially similar to a he configuration in which the case 54Y is removed from the electroacoustic transducer unit 112 of the ninth exemplary embodiment illustrated in
The case 154Y includes a rear wall portion 154R disposed on a rear side, and a cylindrical peripheral wall portion 154D erected from an outer peripheral portion of the rear wall portion 154R. The peripheral wall portion 154D is a component substantially similar to a portion of the peripheral wall portion 54S of the housing 54 of the ninth exemplary embodiment illustrated in
A port 156 is continuously provided at the peripheral wall portion 154D of the case 154Y. As an example, the port 156 is formed by a cylindrical duct 156D extending from the peripheral wall portion 154D toward the inside of the peripheral wall portion 154D in a direction orthogonal to the front-rear direction, and a through-hole (not illustrated) formed in the peripheral wall portion 154D in such a way as to be continuous with an inner space of the duct 156D.
The port 156 is configured to guide a component of a partial frequency band of a sound radiated from the rear surface 28B of the first diaphragm 28 into the cavity S2 on the rear surface 28B side of the first diaphragm 28 (in other words, a sound radiated from the rear surface 28B of the first diaphragm 28 in a direction opposite to a direction in which a front surface 38A of the second diaphragm 38 faces) to an external space S1 on the front surface 38A side of the second diaphragm 38. As the port 156 is provided, the electroacoustic transducer 140 is configured such that a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from the first diaphragm 28 and the second diaphragm 38 in a case in which a drive unit 16 generates vibration is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm 28 and the second diaphragm 38 at the crossover frequency.
The actions and effects substantially similar to those of the ninth exemplary embodiment can also be obtained by the eleventh exemplary embodiment described above.
In the first to eleventh exemplary embodiments illustrated in
As a modification of the first to eleventh exemplary embodiments, a configuration in which the magnetic circuit unit (20) as the action portion has a smaller mass than the voice coil unit (18) as the reaction portion, the first diaphragm (28) is connected to the magnetic circuit unit (20), and the voice coil unit (18) is connected to the second diaphragm (38, 41, 61, 81, 101, or 138) via at least the second suspension (32, 33, 98, 124, 126, or 134) can also be adopted.
In the first to eleventh exemplary embodiments, a configuration in which the drive unit 16 includes the magnetic circuit unit 20 as the action portion and the voice coil unit 18 as the reaction portion and uses the Lorentz force has been described as an example. However, as a modification of the exemplary embodiments, the drive unit may be a drive unit having a configuration other than the configuration using the Lorentz force, such as a known linear actuator that includes two mass bodies of an action portion and a reaction portion and is capable of generating vibration. The linear actuator including two mass bodies of an action portion and a reaction portion is known in, for example, Japanese Patent Application Laid-Open (JP-A) No. 2003-235232, or the like, and thus a detailed description thereof will be omitted.
As for a drive unit having a configuration other than the configuration disclosed in JP-A No. 2003-235232, a speaker including a drive unit capable of generating vibration by including two mass bodies of an action portion and a reaction portion without using the Lorentz force is known in, for example, Japanese Patent No. 3749662, and the drive unit disclosed in the same publication can also be applied to the drive unit of the present disclosure. Although the Lorentz force is used, a drive unit having a configuration different from that of the drive unit 16 of the first to tenth exemplary embodiments is known in, for example, Japanese Patent No. 2936009 (an example of a moving magnet type), Japanese Utility Model Application Publication (JP-Y) No. S61-45745 (an example in which the magnetic circuit unit is divided into an action portion and a reaction portion), and Japanese Patent Application Laid-Open (JP-A) No. H10-285689 (an example in which when a current is supplied to a drive coil, a secondary current is induced in a secondary coil to generate a driving force), and the drive units disclosed in these publications can also be applied to the drive unit of the present disclosure.
As a modification of the first, third, fifth, seventh, and ninth exemplary embodiments, for example, a configuration in which the housing of the electroacoustic transducer unit does not include any component corresponding to the rear wall portions 14R, 54R, 74R, and 174R and any component corresponding to the flange-shaped attachment portions 14A, 54A, 74A, and 174A illustrated in
It is essential that a joining portion between the housing of the electroacoustic transducer unit and the second diaphragm has a joining strength enough to prevent separation, and a joining area enough to transfer vibration from the housing to the second diaphragm. The joining area enough to transfer vibration from the housing to the second diaphragm varies depending on rigidity of the second diaphragm. The electroacoustic transducer including the electroacoustic transducer unit includes the cavity and the port leading to the cavity in a state where the housing and the second diaphragm are joined, and the shape of the housing is premised on such a case. However, a portion of the housing overlapping with and joined to the second diaphragm can have various shapes. To give a supplementary description by way of example, the portion of the housing overlapping with and joined to the second diaphragm may be, for example, arc-shaped portions that are intermittently arranged along an outer periphery of the cavity when viewed in a thickness direction of the second diaphragm.
In addition, as a modification of the first to eleventh exemplary embodiments, the first diaphragm and the first suspension (an edge as an example) may be integrally connected.
The first to eleventh exemplary embodiments and the plurality of modifications described above can be combined, if appropriate.
Although an example of the present disclosure has been described above, the present disclosure is not limited thereto, and it is a matter of course that the present disclosure may be variously modified and implemented without departing from the gist of the present disclosure.
The present disclosure of Japanese Patent Application No. 2021-065225, filed on Apr. 7, 2021, is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-065225 | Apr 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/014680 | 3/25/2022 | WO |
