JP2013223111A - Electroacoustic conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a drive circuit in an electroacoustic conversion device that is both a receiver and a speaker.SOLUTION: A first voice coil 6 is arranged in the circumference of a first permanent magnet 3. A yoke 2 is arranged in the circumference. A second voice coil 8 is arranged in the circumference. A second permanent magnet 4 is arranged in the circumference. An upper part of the first voice coil 6 is fixed to a lower surface of a first diaphragm 5. An upper part of the second voice coil 8 is fixed to a lower surface of a second diaphragm 7. When an electroacoustic conversion device is used as a receiver, a current is allowed to flow in the first voice coil 6 and the first diaphragm 5 is vibrated. When the device is used as a speaker, a current is allowed to flow in the second voice coil 8 and the second diaphragm 7 is vibrated. Consequently, the device can be used as a receiver only by allowing a current to flow in the first voice coil 6, and can be used as a speaker only by allowing a current to flow in the second voice coil 8. Thus, a drive circuit is simplified.

Description

  The present invention relates to an electroacoustic transducer that serves as both a receiver and a speaker.

  In a conventional electroacoustic transducer that also serves as a receiver and a speaker, a piezoelectric diaphragm is provided in the center of the housing, and a sound hole is provided in the housing facing one surface of the piezoelectric diaphragm. A brake hole and an adjustment hole are provided in a housing opposite to the adjustment hole, and an adjustment valve for opening and closing the adjustment hole by an electric signal is provided in the housing in the vicinity of the adjustment hole (see, for example, Patent Document 1).

JP 2006-304021 A

  In the above conventional electroacoustic transducer, when used as a receiver, the damping hole is closed by the regulating valve so that a damping action can be obtained. When the piezoelectric diaphragm vibrates in this state, the sound hole A sound with a relatively low sound pressure level is emitted from the sound source and used as a receiver. On the other hand, when used as a speaker, the adjustment hole is not closed by the adjustment valve, so that the damping action by the braking hole cannot be obtained. When the piezoelectric diaphragm vibrates in this state, the sound pressure level from the sound hole Produces a relatively high sound and is used as a speaker.

  However, the conventional electroacoustic transducer has a problem in that the drive circuit becomes complicated because it is necessary to electrically control the regulating valve.

  Accordingly, an object of the present invention is to provide an electroacoustic transducer capable of simplifying a drive circuit.

  The electroacoustic transducer according to the present invention includes a first permanent magnet, a yoke provided around the first permanent magnet, a second permanent magnet provided around the yoke, and the yoke. A first voice coil provided between the first permanent magnet, a first vibration film provided on an upper portion of the first voice coil, the yoke and the second permanent magnet; A second voice coil provided between the second voice coil and a second diaphragm provided above the second voice coil, and when used as a receiver, the first diaphragm and the second diaphragm One of the diaphragms is vibrated, and when used as a speaker, at least the other diaphragm is vibrated.

  According to the present invention, the drive circuit can be simplified.

The top view of the electroacoustic transducer as 1st Embodiment of this invention. Sectional drawing which follows the II-II line | wire of FIG. The figure shown in order to demonstrate a frequency sound pressure characteristic. Sectional drawing similar to FIG. 2 of the electroacoustic transducer as 2nd Embodiment of this invention.

(First embodiment)
FIG. 1 is a plan view of an electroacoustic transducer as a first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. The electroacoustic transducer includes a bottomed cylindrical frame 1 made of resin. A bottomed cylindrical yoke 2 is fixed to the center of the upper surface of the bottom of the frame 1 with an adhesive (not shown).

  A columnar first permanent magnet 3 is fixed to the center of the upper surface of the bottom of the yoke 2 via an adhesive (not shown). A cylindrical second permanent magnet 4 is fixed to the outer peripheral portion of the upper surface of the bottom portion of the frame 1 with an adhesive (not shown). Here, as an example, the height position of the upper surface of the yoke 2 is the same as the height position of the upper surface of the frame 1. The height position of the upper surface of the first permanent magnet 3 is lower than the height position of the upper surface of the yoke 2. The height position of the upper surface of the second permanent magnet 4 is lower than the height position of the upper surface of the frame 1.

  An outer peripheral portion of the lower surface of the first circular diaphragm 5 made of polyethylene terephthalate or the like is fixed to an inner peripheral portion of the upper surface of the yoke 2 with an adhesive (not shown). The upper part of the first voice coil 6 is fixed to a predetermined location on the lower surface of the first vibration film 5 via an adhesive (not shown). The first voice coil 6 is disposed between the yoke 2 and the first permanent magnet 3 so as to be movable up and down.

  A lower ring inner peripheral portion of a planar ring-shaped second vibration film 7 made of polyethylene terephthalate or the like is fixed to an outer peripheral portion of the upper surface of the yoke 2 with an adhesive (not shown). The outer peripheral portion of the lower surface of the second vibration film 7 is fixed to the upper surface of the frame 1 with an adhesive (not shown). The upper part of the second voice coil 8 is fixed to a predetermined location on the lower surface of the second vibrating membrane 7 with an adhesive (not shown). The second voice coil 8 is disposed between the yoke 2 and the second permanent magnet 4 so as to be movable up and down.

  Here, the first vibrating membrane 5 is designed to vibrate in a low frequency band of about 300 Hz in order to be adapted to the receiver application. The second vibrating membrane 7 is designed to vibrate in a band having a frequency of 1 kHz or more so as to be suitable for a speaker application.

  Therefore, when this electroacoustic transducer is used as a receiver, when a current is passed through the first voice coil 6, the first vibrating membrane 5 vibrates and can be used as a receiver. On the other hand, when this piezoelectric electroacoustic transducer is used as a speaker, when a current is passed through the second voice coil 8, the second vibrating membrane 7 vibrates and can be used as a speaker.

  Thus, in this electroacoustic transducer, it can be used as a receiver by simply passing a current through the first voice coil 6, and it can be used as a speaker by simply passing a current through the second voice coil 8. Therefore, it is not necessary to electrically control a regulator or the like, and the drive circuit can be simplified.

  In addition, since this electroacoustic transducer is constituted by two magnetic circuits, a first magnetic circuit including the first permanent magnet 3 and a second magnetic circuit including the second permanent magnet 4, Since the magnetic circuit to be used can be selected depending on the intended use of the receiver and the required sound pressure level, power consumption can be reduced. Further, the two permanent magnets 3 and 4 can be formed of different compositions, for example, ferrite and neodymium, respectively, which is effective for supply of rare earth and cost reduction.

  When used as a speaker, a higher sound pressure level can be obtained by passing a current through not only the second voice coil 8 but also the first voice coil 6. For example, referring to the frequency sound pressure characteristic shown in FIG. 3, when a current is passed through only the second voice coil 8, the frequency sound pressure characteristic indicated by the solid line is obtained. However, when a current is applied, a higher sound pressure level is obtained as shown by the dotted line than when the current is passed. Also in this case, it is only necessary to pass a current through the first voice coil 6 and the second voice coil 8, so that the drive circuit can be simplified.

  Here, contrary to the above, the first diaphragm 5 is designed to vibrate in a frequency band of 1 kHz or more so as to be suitable for a speaker application, and the second diaphragm 7 is adapted for a receiver application. When it is designed to vibrate in a low frequency band of about 300 Hz, of course, when a current is passed through the first voice coil 6, it can be used as a speaker. When current is passed, it can be used as a receiver.

  By the way, since the height position of the upper surface of the second permanent magnet 4 is lower than the height position of the upper surface of the frame 1, the second permanent magnet 4 is obstructed when the second vibrating membrane 7 vibrates. Therefore, the vibration area of the second vibration film 7 can be increased as compared with the case where the lower surface of the second vibration film 7 is fixed to the upper surface of the second permanent magnet 4.

(Second Embodiment)
FIG. 3 is a sectional view similar to FIG. 2 of an electroacoustic transducer as a second embodiment of the present invention. This electroacoustic transducer differs from the electroacoustic transducer shown in FIG. 2 in that the first diaphragm 5 and the second diaphragm 7 are formed by a single diaphragm 11. In this case, the outer peripheral surface of the lower surface of one vibration film 11 is fixed to the upper surface of the frame 1 via an adhesive (not shown), and a predetermined ring-shaped portion of the lower surface is bonded to the upper surface of the yoke 2 (see FIG. (Not shown).

  In this case, as compared with the case shown in FIG. 2, only one vibration film 11 is required, so that the number of parts can be reduced and the cost can be reduced. The number of fixings to the yoke 2 via the adhesive is reduced from 4 to 2, and the assembling work can be facilitated accordingly.

  Hereinafter, various aspects of the present invention will be collectively described as supplementary notes.

(Appendix 1)
The invention of appendix 1 includes a first permanent magnet, a yoke provided around the first permanent magnet, a second permanent magnet provided around the yoke, the yoke, and the first permanent magnet. A first voice coil provided between the permanent magnet, a first vibration film provided on an upper portion of the first voice coil, and provided between the yoke and the second permanent magnet; A second voice coil and a second diaphragm provided on the second voice coil, and when used as a receiver, the first diaphragm and the second diaphragm The electroacoustic transducer is characterized in that when one of the diaphragms is vibrated and used as a speaker, at least the other diaphragm is vibrated.

(Appendix 2)
The invention according to appendix 2 is the electroacoustic transducer according to the invention according to appendix 1, wherein the first vibrating membrane and the second vibrating membrane are vibrated together when used as a speaker.

(Appendix 3)
The invention of appendix 3 is the invention according to appendix 1 or 2, wherein the bottomed cylindrical frame, the bottomed cylindrical yoke provided at the center of the bottom upper surface of the frame, and the center of the top surface of the yoke The first permanent magnet provided on the frame, the cylindrical second permanent magnet provided on the outer periphery of the upper surface of the bottom of the frame, and movable between the yoke and the first permanent magnet. And the first voice coil provided on the yoke and the second voice coil provided between the yoke and the second permanent magnet so as to be movable up and down. It is a conversion device.

(Appendix 4)
The invention according to appendix 4 is the invention according to appendix 3, wherein the first vibrating membrane is circular, and the outer peripheral portion of the lower surface of the first vibrating membrane is fixed to the upper surface of the yoke, and the second vibrating membrane The membrane has a ring shape, and the inner peripheral portion of the lower surface of the second vibrating membrane is fixed to the upper surface of the yoke, and the outer peripheral portion of the lower surface of the second vibrating membrane is fixed to the upper surface of the frame. This is an electroacoustic transducer.

(Appendix 5)
The invention according to appendix 5 is the invention according to appendix 3, wherein the first vibrating membrane is formed by a central portion of one circular vibrating membrane, and the second vibrating membrane is formed of the one vibrating membrane. The electroacoustic transducer is formed by an outer peripheral portion, and the one vibration film is fixed to an upper surface of the yoke and an upper surface of the frame.

(Appendix 6)
The invention according to appendix 6 is the electroacoustic according to the invention according to appendix 4 or 5, wherein the height position of the upper surface of the second permanent magnet is lower than the height position of the upper surface of the frame. It is a conversion device.

DESCRIPTION OF SYMBOLS 1 Frame 2 Yoke 3 1st permanent magnet 4 2nd permanent magnet 5 1st vibration film 6 1st voice coil 7 2nd vibration film 8 2nd voice coil

Claims (6)

  A first permanent magnet, a yoke provided around the first permanent magnet, a second permanent magnet provided around the yoke, and between the yoke and the first permanent magnet A first voice coil provided; a first vibration film provided on an upper portion of the first voice coil; and a second voice coil provided between the yoke and the second permanent magnet. And a second diaphragm provided on top of the second voice coil, and when used as a receiver, one of the first diaphragm and the second diaphragm An electroacoustic transducer characterized in that, when used as a speaker, at least the other vibrating membrane is vibrated.   The electroacoustic transducer according to claim 1, wherein when used as a speaker, the first vibrating membrane and the second vibrating membrane are vibrated together.   The invention according to claim 1 or 2, wherein the bottomed cylindrical frame, the bottomed cylindrical yoke provided at the center of the bottom upper surface of the frame, and the top surface of the yoke provided at the center of the upper surface. The first permanent magnet, the cylindrical second permanent magnet provided on the outer periphery of the bottom upper surface of the frame, and the yoke provided between the yoke and the first permanent magnet so as to be movable up and down. An electroacoustic transducer comprising: a first voice coil; and the second voice coil provided to be movable up and down between the yoke and the second permanent magnet.   According to a third aspect of the present invention, the first diaphragm is circular, the outer periphery of the lower surface of the first diaphragm is fixed to the upper surface of the yoke, and the second diaphragm is ring-shaped. The electroacoustic conversion is characterized in that the inner peripheral portion of the lower surface of the second diaphragm is fixed to the upper surface of the yoke, and the outer peripheral portion of the lower surface of the second diaphragm is fixed to the upper surface of the frame. apparatus.   According to a third aspect of the present invention, the first vibration film is formed by a central portion of one circular vibration film, and the second vibration film is formed by an outer peripheral portion of the one vibration film. The electro-acoustic transducer is characterized in that the one vibration film is fixed to the upper surface of the yoke and the upper surface of the frame.   6. The electroacoustic transducer according to claim 4, wherein a height position of the upper surface of the second permanent magnet is lower than a height position of the upper surface of the frame.

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