JP6578554B2 - Vibration speaker - Google Patents

Description

  The present invention relates to a vibration speaker, and more particularly to a vibration speaker that can obtain a wide frequency characteristic from a low sound range to a high sound range.

  There is a growing demand to listen to music like BGM in the room, etc. However, in order to change the interior of the room by opening a hole in the ceiling or wall and installing a speaker, or installing a separate speaker box Often there is resistance. In addition, there is an increasing demand for listening to music in bathrooms and kitchens, but if you make a hole in the ceiling plate or wall plate or install another speaker box, it will become dirty and dirty. In some cases, waterproofing is required. A vibration speaker is desired to be used in such a case.

A normal speaker emits sound by directly vibrating air with a diaphragm built in the speaker, whereas a loudspeaker itself does not have a function to vibrate air greatly, so it makes a loud sound. Absent. However, by installing the diaphragm of the vibration speaker in close contact with the ceiling plate, wall plate, etc., the closely attached ceiling plate or wall plate can vibrate the air and emit sound like a normal speaker. .
For example, a wall speaker and an elevator in which a vibration speaker is attached to a wall plate are disclosed (see Patent Documents 1 and 2).

Here, a general structure of the vibration speaker will be described. FIG. 3 is a schematic sectional view showing the structure of a conventional vibration speaker.
The vibration speaker 100 includes a magnetic circuit body 12 having a magnetic gap 12a formed in a part thereof, a cylindrical voice coil 13 disposed in the magnetic gap 12a, and a circular shape in which the upper end of the voice coil 13 is fixed. A diaphragm 14 (resin diaphragm or metal diaphragm) and a frame 15 that fixes the periphery of the diaphragm 14 to a magnetic circuit body 12 (top plate 20 portion described later) are provided.

  The magnetic circuit body 12 includes a bottom plate 18 made of a magnetic material, a magnet 19, and a top plate 20 made of a magnetic material.

  The bottom plate 18 includes a cylindrical portion 18a serving as an inner wall, and a flange-shaped disk portion 18b extending outward from a lower portion (lower inner wall) of the cylindrical portion 18a and serving as a lower wall. A cylindrical hole 18c is provided along the central axis of the disc portion 18b). The cylindrical portion 18a corresponds to a so-called “center pole” in a normal speaker. Many ordinary speakers do not have a through-hole in the center of the center pole, but even if a through-hole having a hole diameter about half the diameter of the voice coil 13 is provided, there is no problem in the magnetic circuit design. Conventionally, a through-hole has been formed at this position for various purposes (for example, back pressure adjustment of the voice coil section and wiring space for the input signal line).

The magnet 19 has an inner peripheral surface 19a having a larger diameter than the outer peripheral surface 18d of the cylindrical portion (inner wall) 18a, and forms an annular body serving as an outer wall. The magnet 19 is magnetically attached to the outer peripheral side (the outer peripheral side of the lower wall) of the disc part 18b so as to be coaxial with the cylindrical part 18a.
The top plate 20 has an inner peripheral surface 20a having a larger diameter than the outer peripheral surface 18d of the cylindrical portion (inner wall) 18a and a smaller diameter than the inner peripheral surface 19a of the magnet 19, and forms an annular body serving as an upper wall. The top plate 20 is magnetically attached to the upper portion (outer wall upper portion) of the magnet 19 so as to be coaxial with the cylindrical portion 18a.

  By arranging the bottom plate (inner wall, lower wall) 18, magnet (outer wall) 19, and top plate (upper wall) 20 in this way, the inner peripheral surface 20a of the top plate 20 and the outer peripheral surface 18d of the cylindrical portion 18a A substantially donut-shaped magnetic circuit body 12 having a magnetic gap 12a therebetween is formed. A cylindrical voice coil 13 is arranged in the magnetic gap 12a.

In the vibration speaker 100, the diaphragm 14 and the upper end of the voice coil 13 are fixed with an adhesive. Therefore, when the voice coil 13 is driven by an input voltage signal input via a signal line (not shown), the vibration of the voice coil 13 is transmitted to the diaphragm 14 to drive it.
The driven wall (ceiling board, wall board, etc.) that is in close contact with the diaphragm 14 vibrates, and this acts as a speaker, and the input voltage signal applied to the voice coil 13 is converted into a sound wave and amplified into a sound. It can be heard.

Japanese Utility Model Publication No. 52-21050 JP 2009-196794 A

  By the way, in the above-described vibration speaker 100, it is necessary to drive the heavy diaphragm 14 with the large voice coil 13 in order to secure the driving force and the allowable input in the middle and low range of about 3 kHz or less. In these heavy vibration systems, the driving force of high frequency is consumed as heat, so that the diaphragm 14 cannot be moved, and there is a problem that reproduction of the high sound range becomes insufficient. On the other hand, it has been desired that even a vibration speaker can produce a wide-band reproduction sound equivalent to that of a normal speaker.

  Therefore, the present invention provides a vibration speaker capable of reproducing a wide-band sound that is the same as or higher than that of a normal speaker through an attached ceiling plate or wall plate even when a vibration speaker is used. Let it be an issue.

  The vibration speaker of the present invention made to solve the above problems includes a magnetic circuit body made of a magnetic material including a magnet, a voice coil, and a diaphragm, and the magnetic circuit body has a cylindrical hole. An inner wall, a lower wall connected to the lower portion of the inner wall, an outer wall connected to the outer peripheral side of the lower wall, and an upper wall connected to the upper portion of the outer wall are substantially donut-shaped magnetic circuits, and a magnetic gap is partially formed The voice coil is disposed in the magnetic gap, the upper end of the voice coil is fixed to the diaphragm, and the periphery of the diaphragm is supported by the magnetic circuit body through a frame. A treble actuator provided with a laminated piezoelectric vibrator in a cylindrical hole in the inner wall of the magnetic circuit body, the upper end of the treble actuator being fixed to the diaphragm, and the lower end being the vibration The high-frequency actuator is held in contact with the diaphragm and the holding member, and an input voltage signal drives the voice coil and the laminated piezoelectric vibrator. It is configured as follows.

  According to the present invention, the voice coil is fixed to the diaphragm, and the high-pitched actuator made of the laminated piezoelectric vibrator is disposed in the cylindrical hole on the inner wall of the magnetic circuit body (that is, near the center of the diaphragm). It is fixed and held on the diaphragm in a pressure contact state so that vibration is transmitted so that no gap is generated between the holding member and the holding member.

  This “laminated piezoelectric vibrator” is a laminate of piezoelectric ceramics and has the property of vibrating (stretching) in proportion to the applied voltage. The vibration width (stretching width) is the length of the laminated piezoelectric ceramic. It depends on. While the voice coil does not vibrate when pressed down strongly, the laminated piezoelectric ceramic moves by expanding and contracting the solid body of the laminated piezoelectric ceramic. This property (can be vibrated even with a heavy diaphragm) is suitable for high-frequency actuators.

When a treble actuator using a laminated piezoelectric vibrator is attached to the diaphragm in a pressure contact state, the expansion / contraction (vibration) of the treble actuator (laminated piezoelectric vibrator) can be transmitted to the diaphragm as it is.
Therefore, by sending the input voltage signal to the voice coil and also sending the input voltage signal to the treble actuator and adding the driving force to the driving force of the voice coil, the diaphragm can be used in a wide range from low to high frequencies. The driving force can be given.

  According to the present invention, it is possible to realize a vibration speaker that can be reproduced with a wide frequency characteristic similar to that of a normal speaker simply by being attached to a ceiling or a wall plate.

In the above invention, the treble actuator includes a vibration blocking member including at least one of a metal weight and an elastic body attached to a lower end of the multilayer piezoelectric vibrating body, and is fixed to the holding member via the vibration blocking member. You may do it.
Expansion and contraction (vibration) of the laminated piezoelectric vibrating body constituting the high-frequency actuator is transmitted from the upper end to the diaphragm. At that time, unnecessary expansion and contraction (vibration) in the opposite direction is transmitted to a vibration blocking member including either a metal weight or an elastic body (such as a rubber cushion) that is heavier than the weight of the laminated piezoelectric vibrating body used. When a metal weight is attached, vibration is suppressed and attenuated by the weight of the metal weight heavier than the weight of the laminated piezoelectric vibrator to be used, and one of the laminated piezoelectric vibrators is securely pressed against the diaphragm. There is an effect to help. In the case of an elastic body, unnecessary reverse vibration is absorbed and damped, and there is an effect of helping to securely press one of the laminated piezoelectric vibrators to the diaphragm. By attaching either one or both, unnecessary reverse vibration can be greatly attenuated.

In the above invention, the holding member has a U shape with a bottom surface and a pair of left and right side surfaces extending from the bottom surface, and the bottom surface is fixed to the diaphragm via the pair of left and right side surfaces. The treble actuator may be pressed.
By making the holding member U-shaped, the lower end of the treble actuator can be stably supported in a pressure-contact state, and unnecessary reverse expansion and contraction (vibration) from the lower end causes the side surface of the holding member to Since it is transmitted to the diaphragm, it attenuates while passing through the side surface and is hardly transmitted to the diaphragm.

In the above invention, the diaphragm is provided with a disk-shaped metal diaphragm on the inside and an annular resin diaphragm on the outside, and the voice coil and the treble actuator are fixed to the metal diaphragm. The resin diaphragm may be supported by the magnetic circuit body via the frame, and the metal diaphragm and the resin diaphragm may be in contact with each other at the periphery so that vibration is transmitted. .
A resin diaphragm (for example, made of ABS resin or POM resin) has a damper spring effect more than a metal diaphragm (for example, made of aluminum or iron), so that the vibration generated and transmitted by the voice coil and the treble actuator is not transmitted. While it is possible to effectively prevent the demerit of vibration transmission efficiency drop due to escape from the frame, on the other hand, the vibration is transmitted to the driven wall (ceiling plate, wall plate, etc.) that is in close contact with the diaphragm The transmission efficiency is also attenuated. Therefore, the diaphragm is composed of an annular resin diaphragm (outside) and a disk-shaped metal diaphragm (inside), and the voice coil and the treble actuator are fixed to the inner metal diaphragm. By making the frame supporting the diaphragm fixed to the annular resin diaphragm, the transmission efficiency of vibration from the voice coil or the treble actuator to the driven wall can be increased.

In the above invention, an input voltage signal for driving the voice coil may simultaneously drive the laminated piezoelectric vibrator.
In general, a laminated piezoelectric vibrator has high impedance and a response frequency of about 3 kHz or higher, so that a treble actuator and a voice coil can be driven in parallel by a signal from one amplifier.

1 is a schematic cross-sectional view showing the structure of a vibration speaker that is an embodiment of the present invention. The comparison figure which shows the frequency characteristic of the vibration speaker of FIG. 1 and the conventional vibration speaker. The schematic sectional drawing which shows the structure of the conventional vibration speaker.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and it goes without saying that the present invention can be modified without departing from the spirit of the present invention.

  FIG. 1 is a schematic sectional view showing a structure of a vibration speaker 10 according to an embodiment of the present invention. In addition, about the component same as the conventional vibration speaker 100 demonstrated using FIG. 3, the description is abbreviate | omitted by attaching | subjecting the same code | symbol.

The vibration speaker 10 uses the same magnetic circuit body 12, voice coil 13, and frame 15 of the conventional vibration speaker 100 described in FIG. 3.
Further, the diaphragm 14 shown in FIG. 3 is entirely made of resin or metal, and the same one may be used as it is. However, in this embodiment, the inside is made of a disk-like metal. A diaphragm 14a is provided, and an annular resin diaphragm 14b is provided outside the diaphragm 14a, and a peripheral edge portion serving as a boundary is in contact so that vibration is transmitted at the boundary between the metal diaphragm 14a and the resin diaphragm 14b. I have to do it.

  A voice coil 13 and a treble actuator 30 to be described later are fixed to the metal diaphragm 14a, the frame 15 is connected to the resin diaphragm 14b, and the frame 15 is connected to the magnetic circuit body 12 (top). Plate 20). A driven wall such as a ceiling plate or a wall plate is in contact with a portion of the metal diaphragm 14a, and vibrations from the voice coil 13 and the treble actuator 30 are efficiently transmitted from the metal diaphragm 14a to the driven wall. In addition, the escape of vibration through the frame 15 is suppressed by the resin diaphragm 14b.

  A treble actuator 30 is disposed in the cylindrical hole 18c of the cylindrical portion 18a (inner wall of the magnetic circuit body 12). The treble actuator 30 includes a laminated piezoelectric vibrator 31. The laminated piezoelectric vibrator 31 is formed by laminating piezoelectric ceramics, and has a high impedance and a response frequency of usually 500 Hz to 20 kHz or more. However, the frequency response may be wider than that, and vice versa. It may be narrow.

  In the present embodiment, the laminated piezoelectric vibrator 31, the metal weight 32, and the rubber cushion 33 are arranged side by side in the vertical direction, and are pressed against the metal diaphragm 14a using the U-shaped holding member 34. It is fixed. That is, the upper end side of the laminated piezoelectric vibrator 31 is in direct contact with the lower surface of the metal diaphragm 14 a, and the lower end side of the laminated piezoelectric vibrator 31 is in contact with the upper surface of the metal weight 32. The lower surface of the metal weight 32 is in contact with the upper surface of the rubber cushion 33, and the lower surface of the rubber cushion 33 is in contact with the bottom surface (support surface) 34 a of the holding member 34. The pair of left and right side surfaces 34b, 34b of the holding member 34 has a length in the vertical direction slightly shorter than the total length of the stacked piezoelectric vibrator 31, the metal weight 32, and the rubber cushion 33 in the vertical direction. In addition, when the holding member 34 is fixed to the metal diaphragm 14a with the fastening member (screw) 35, the holding member 34 is brought into pressure contact with no gap.

  The metal weight 32 and the rubber cushion 33 are attached in order to function as a vibration blocking member that blocks vibration transmitted from the lower end side of the laminated piezoelectric vibrating body 31. There is no problem, but the transmission efficiency of vibration is somewhat lowered due to the expansion and contraction in the opposite direction at the lower end. When the vibration blocking member (metal weight 32, rubber cushion 33) is not provided, the lower end side of the laminated piezoelectric vibrating body 31 directly contacts the bottom surface 34a of the holding member 34. Also in this case, the U-shaped holding member 34 having an appropriate length of the side surface 34b is brought into a pressure contact state so that no gap is generated between the upper end and the lower end of the laminated piezoelectric vibrator 31.

  An input voltage signal is applied to the voice coil 13 and the laminated piezoelectric vibrator 31 of the treble actuator 30, but the impedance is high, and the response frequency is usually from about 3 kHz or more to 20 kHz or more. Therefore, the input signals from one amplifier can be connected and driven in parallel. However, actually, the response frequency band of the laminated piezoelectric vibrator 31 may be an arbitrary frequency band from several hundred Hz, which is lower, to 20 kHz or more. If there is no problem in increasing the number of parts, it may be driven separately using two amplifiers dedicated to high and middle tones.

Next, frequency characteristics of the vibration speaker embodying the present invention will be described.
FIG. 2 is a diagram showing the frequency characteristics (solid line) of the vibration speaker 10 shown in FIG. As a comparative example, the frequency characteristic (broken line) of the conventional vibration speaker 100 shown in FIG. 3 is also shown.
In the comparative example (broken line), the sound pressure decreases in the high sound range from around 3 kHz, whereas in the present invention (solid line), the sound pressure does not drop to around 20 kHz, and the frequency characteristics are greatly improved.

  Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and modifications can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, the upper end of the laminated piezoelectric vibrator 31 is in direct contact with the lower surface of the metal diaphragm 14a. However, the metal diaphragm 14a is interposed via a metal rod having a light material and shape. You may make it transmit a vibration to.
Further, corrugations may be provided on the diaphragms 14a and 14b.
Further, a slit or the like may be provided in the diaphragms 14a and 14b to lower the resonance frequency.

  The present invention can be used for a vibration speaker having a wide frequency characteristic.

DESCRIPTION OF SYMBOLS 10 Vibration speaker 12 Magnetic circuit body 12a Magnetic gap 13 Voice coil 14 Diaphragm 14a Metal diaphragm 14b Resin diaphragm 15 Frame 18 Bottom plate 18a Cylindrical part (inner wall)
18b Disc (bottom wall)
18c Tube hole (through hole)
18d Cylindrical outer peripheral surface 19 Magnet (outer wall)
19a Magnet inner peripheral surface 20 Top plate (upper wall)
20a Top plate inner peripheral surface 30 Treble actuator 31 Multilayer piezoelectric vibrator 32 Metal weight 33 Rubber cushion (elastic body)
34 Holding member 34a Bottom surface 34b Side surface 35 Fastening member (screw)

Claims (5)

A magnetic circuit body composed of a magnetic body including a magnet, a voice coil, and a diaphragm;
The magnetic circuit body includes an inner wall having a cylindrical hole, a lower wall connected to the lower part of the inner wall, an outer wall connected to the outer peripheral side of the lower wall, and an upper wall connected to the upper part of the outer wall. And forming a magnetic circuit in which a magnetic gap is formed in part,
The voice coil is disposed in the magnetic gap, and an upper end thereof is fixed to the diaphragm,
A peripheral edge of the diaphragm is a vibration speaker supported by the magnetic circuit body via a frame,
A treble actuator provided with a laminated piezoelectric vibrator is disposed in a cylindrical hole in the inner wall of the magnetic circuit body,
The upper end of the treble actuator is fixed to the diaphragm, the lower end is fixed to a holding member supported by the diaphragm, and the treble actuator is held in pressure contact between the diaphragm and the holding member. ,
A vibration speaker, wherein an input voltage signal drives the voice coil and the laminated piezoelectric vibrator.   2. The treble actuator according to claim 1, wherein a vibration blocking member including at least one of a metal weight and an elastic body is attached to a lower end of the laminated piezoelectric vibrating body, and is fixed to the holding member via the vibration blocking member. The vibration speaker described.   The holding member has a U shape with a bottom surface and a pair of left and right side surfaces extending from the bottom surface, and the bottom surface is fixed to the diaphragm via the pair of left and right side surfaces, and the treble actuator is The vibration speaker according to claim 1 or 2, which is press-contacted. The diaphragm is provided with a disk-shaped metal diaphragm on the inside, an annular resin diaphragm is provided on the outside, the voice coil and the treble actuator are fixed to the metal diaphragm, and the resin A vibration plate is supported by the magnetic circuit body via the frame,
The vibration speaker according to any one of claims 1 to 3, wherein the metal diaphragm and the resin diaphragm are in contact with each other at a periphery so that vibration is transmitted.   The vibration speaker according to any one of claims 1 to 4, wherein an input voltage signal for driving the voice coil drives the laminated piezoelectric vibrator at the same time.

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