JPH11262091A - Loudspeaker device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cancel or attenuate reaction force at the time of driving a vibration plate by providing an airtight plate for reflecting sound on the front surface of the plate into a loudspeaker box and piercing through-holes in the vibration plate or a cap facing the airtight plate. SOLUTION: Plural thin through-holes 21 are pierced at prescribed positions on a vibration plate 10, and an airtight space part 25 is formed between an airtight plate 24 and the plate 10. When the number of the plural holes 21 pierced in the plate 10 is taken to be n, air flows into a first space part 20a which is formed at the front side of a dumper 17 by the vibration of the plate 10, and the pressure inside the volumes of the two space parts 20a and 20b fluctuates. An action force FD/n and a reaction force -FD/n as with respect to it are generated by air flowing into the first space part 20a in the holes 21 of the plate 10. Therefore, when the number of the holes 21 is made to be n, action force FD/n and reaction force -FD/n as against it are generated by the flow-in air in the holes 21 of the dumper 17. Therefore, balancing is applied to obtain FD/n+FD/n+ and so on = F1 , so that the reaction force of -F1 and the reaction force of -(FD/n+FD/n + and so on) are cancelled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and lightweight speaker device, and more particularly to a speaker device capable of canceling a reaction of sound radiation from a speaker device using one speaker.

[0002]

2. Description of the Related Art Conventionally, as an effective means for extending the low-frequency reproduction limit of a speaker device, for example, an opening and a duct are provided in a baffle plate provided with a speaker, and a phase of a sound emitted from a back surface of a diaphragm of the speaker is adjusted. A bass reflex type (phase inversion type) speaker device which inverts and radiates to the outside through an opening through a duct to enhance the sound wave emitted from the diaphragm of the speaker to the front so as not to distort the bass range is well known. Have been.

[0003] Such a phase inversion type speaker device is shown in FIG.
As shown in FIG. 1A, a speaker 3 is fixed to a speaker sound emission hole 2a formed in a baffle plate 2 provided on the front surface of a speaker box 1.

As shown in FIG. 6A, for example, a speaker 3 is provided with a ring-shaped magnet 4, a plate 5 having a center hole, and a yoke 6 attached so as to sandwich the ring-shaped magnet 4. A magnetic gap 7 is formed between the inner peripheral side of the plate 5 and the center pole 6a of the yoke 6. A frame 8 of the speaker 3 is attached to the plate 5, and an edge 9 is provided on an outer peripheral portion of the frame 8.
The outer periphery of the cone-shaped diaphragm 10 is held by a gasket or the like by the edge 9.

On the other hand, a voice coil bobbin 11 is mounted on the inner peripheral portion of the diaphragm 10, and a voice coil 12 is wound around the voice coil bobbin 11, and the voice coil 12 is formed by a center pole 6 a of the plate 5 and the yoke 6. It is designed to be inserted into the formed magnetic gap 7. Reference numeral 17 denotes a damper for holding the voice coil 12 in the magnetic gap 7.

An acoustic signal from an input terminal 13a provided at a predetermined position outside the speaker box 1 is connected to a connection line 1
4a to the terminal 15 of the speaker 3 via the terminal 15a.
Of the voice coil 12 via the tinsel wire 16
To supply.

Also, a duct 18 having an opening 18a is provided on the same surface as the speaker sound emission hole 2a of the baffle plate 2, and the phase of the sound emitted from the back surface of the diaphragm 10 of the speaker 3 is inverted.
Radiating from the duct 18 to the outside of the speaker box 1,
The bass range of the sound coming from the front of the diaphragm 10 is widened.

As described above, an electrical equivalent circuit of the phase inversion type speaker device can be represented as shown in FIG.

In FIG. 6A and FIG. 6B, S ₀ is the stiffness of the support system of the speaker 3, M ₀ is the equivalent mass of the support system of the speaker 3, R _ms0 is the mechanical resistance of the speaker support system, and R _m0 is the mechanical resistance of the air loading of the speaker, R ₀ is expressed by R _m0 + R _ms0 = R ₀ equivalent mechanical resistance of the speaker. S
_C is stiffness in the speaker box 1, R _D is the mechanical resistance of the air loading of the duct 18 portions, M _D is the air mass in the duct 18 portions.

[0010] With above phase inversion type speaker apparatus as in, to be able to lower the bass reproduction limit compared to sealed, about 80% of the lowest resonance frequency f ₀ of the speaker 3
It is said that the low-frequency reproduction range can be extended to a degree.

In such a loudspeaker device, the sound radiation force F ₁ due to the vibration of the diaphragm 10 of the loudspeaker 3 is equal to the acceleration α ₀ acting on the loudspeaker diaphragm 10 on the equivalent mass M ₀ of the loudspeaker 3 in FIG. F ₁ = M ₀ α ₀ To such sound radiation force F _1, the reaction force -F ₁ toward the speaker box 1 from the rear side of the diaphragm 10 also becomes remarkable the smaller the volume of the speaker box 1 speaker device is small and light, The vibration of the diaphragm 10 causes the speaker box 1
The air inside is repeatedly compressed and expanded, and this air is
There is a problem that the speaker box 1 is rocked because it acts as a force for returning 0 to the original position, and the bass reproduction is hindered.

In order to solve such a problem, the present applicant has previously proposed a speaker device as shown in FIG. 7. In FIG. 7, portions corresponding to those in FIG. 6 are denoted by the same reference numerals.

In FIG. 7, a speaker box 1 is formed in a box shape of a synthetic resin and is integrally formed with a baffle plate 2. The speaker 3 having the same configuration as that described in detail in FIG. 6A is fixed to the speaker sound emitting hole 2a formed on the upper side of the baffle plate 2. First duct 1 arranged below baffle plate 2
8 and the opening 18a are integrally formed when the baffle plate 2 is formed.

Further, a speaker sound emission hole 2b is formed at a position opposite to the speaker sound emission hole 2a formed on the baffle plate 2 above the rear face plate 1B, and the second speaker 3b, preferably, the speaker 3 and the back surface are connected. Is fixed to the rear plate 1B so that the first
Second duct 18b having a larger duct diameter than the second duct 18
Are overlapped within a predetermined length of the first duct 18 and are planted integrally with the rear plate 1B so as to form a concentric cross section, and the first through the opening 18c of the second duct 18b.
Equivalent mass M of air radiating to the opening 18a of the duct 18
_D and the equivalent resistance _RD are configured to be large.

Further, the first and second speakers 3 and 3b
Are supplied with the same input acoustic signal via input terminals 13a and 13b and connection lines 14a and 14b disposed on the rear panel 1B.

According to the speaker device shown in FIG.
Radiation force F _D1 between the first and second ducts 18 and 18b
And _{F D2 / 2 + F D2 /} 2 of the reaction force -F _D1 and -F _D2 /
2 + (− F _D2 / 2) cancel each other, so that the reaction forces −F ₁ and −F ₂ of the radiation forces F ₁ and F ₂ of the first and second speakers 3a and 3b are F ₁ ≒ F ₂ . Then they can offset each other.

[0017]

[SUMMARY OF THE INVENTION] However, in the speaker box 1 in order to as in the above-mentioned structure does not swing supporting reaction forces -F ₁ by acting force F ₁ of the speaker 3 small and lightweight speaker box 1 In addition, there is a problem that a pair of speakers 3 and 3b having substantially the same structure is required, which is not only a bottleneck for miniaturization but also expensive.

Furthermore, in the conventional small speaker, the magnet of the magnetic circuit for driving the diaphragm is very small, and the voice coil is wound around a small-diameter voice coil bobbin to increase the sound pressure of the speaker. The resonance sharpness (hereinafter referred to as Q ₀ ) of the frequency (hereinafter referred to as f ₀ ) was inevitably increased.

[0019] In addition, of the large small speaker of such a Q ₀ in Q ₀ is the low frequency range for further increases in the f ₀ can not play the expansion of the low-pass If you have disposed in the speaker box of small volume There was a problem that the sound quality was significantly deteriorated.

In general, a very small speaker often uses a fixed edge, which simultaneously forms an edge when the diaphragm is made, but the fixed edge of such a small speaker is hard and the voice coil is lightweight, so that the speaker is light. There is a problem that it is also difficult to lower f ₀ of.

Further, the vibration system of the speaker was made equal.
One of Q ₀ is higher f ₀ is the speaker had adverse effects become unsuitable for reproduction of low frequency increases in proportion to f _0.

An object of the present invention is to provide a speaker device which solves the above-mentioned problems, and a problem to be solved by the present invention is to provide a small and lightweight speaker box by performing simple processing on one speaker unit. To offset or attenuate the reaction force of the radiating force of the loudspeaker, to prevent rocking of the loudspeaker device, to radiate a strong low frequency band, to reduce Q ₀ , and to set f ₀ of the loudspeaker to the low frequency side. To perform low-frequency expansion and good-quality low-frequency radiation.

[0023]

According to the speaker device of the present invention, an airtight plate for reflecting the sound of the diaphragm into the speaker box is provided on the front surface of the diaphragm, and the diaphragm or cap facing the airtight plate is provided. A hole is formed in the hole.

According to the loudspeaker apparatus of the present invention, the simple processing of one loudspeaker cancels out the reaction due to the radiating force of the loudspeaker built in the small and lightweight loudspeaker box, thereby preventing oscillation and increasing the low frequency range. capable expansion is obtained the f ₀ lower the Q ₀ of the speaker by an equivalent mass of air passing through the plurality of through holes that bored in the diaphragm to the low frequency side while.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A small speaker according to the present invention will be described below in detail with reference to FIGS. In the present invention, parts corresponding to the speakers shown in FIGS. 6 and 7 are denoted by the same reference numerals.

FIG. 1A is a side sectional view of a speaker used in the speaker device of the present embodiment, and FIG.
A cross-sectional view taken along the line A 'is shown, and reference numeral 3 denotes a small speaker as a whole according to the present embodiment. A yoke 6 is a disc-shaped portion made of a plate material such as pure iron, and is erected at the center of the disc-shaped portion. A cylindrical center pole 6a and a magnet guide portion 6b formed of a step formed concentrically with the center pole 6a in a disk-like portion are integrally formed.

The ring-shaped magnet 4 magnetized in the thickness direction of ferrite or the like is bonded on the disc-shaped portion of the yoke 6 via an adhesive. The inner diameter of the ring-shaped magnet 4 is fitted and positioned in a step portion of a magnet guide portion 6b formed in a disk-shaped portion of the yoke 6.

The plate 5 is joined to the magnet 4. In this case, the gap guide is left inserted in the center pole 6a, and an adhesive is applied to the upper surface of the magnet 4, and the inner diameter of the plate 5 is inserted into the outer diameter of the gap guide and fixed. The plate 5 is made of a pure iron or the like in the form of a disk, and is a punched plate material having a through hole at the center, and a magnetic gap 7 formed between the inner peripheral edge of the through hole and the outer diameter of the center pole 6a.
The voice coil 12 is provided inside.

A metal part of a magnetic circuit is formed by fixing a funnel-shaped frame 8 made of steel or the like to the plate 5. Below the magnetic gap 7, the outer circumference of the center pole 6 a and the inner diameter of the magnet 4 are defined. An enclosed second space 20b is formed.

A voice coil 12 wound around a cylindrical voice coil bobbin 11 is provided in the magnetic space 7 of the magnetic circuit.
Is inserted, and the voice coil bobbin 11 is held via an airtight damper 17 having a corrugation of a waveform capable of vibrating in the vertical direction. In order to obtain an airtight damper 17, two or three thin cloths are stacked and joined to form a damper, or a material obtained by applying a synthetic resin solution or the like to the surface of the damper 17 is used.

The inside diameter of the damper 17 is joined to the middle part of the voice coil bobbin 11 via an adhesive, and the outside diameter part is joined to the outer periphery of the bottom surface of the frame 8. Further, the inner diameter of a funnel-shaped diaphragm 10 having a free or fixed edge 9 made of paper or the like is attached to a voice coil bobbin
And the largest diameter portion of the diaphragm 10 is fixed to the peripheral edge of the upper opening of the frame 8 via a gasket 19.

As shown in the plan view of FIG. 1B, which is a sectional view taken along the line AA 'in FIG. 1A, a plurality of thin through holes 21 are formed in predetermined positions in the diaphragm 10. In 1 (B), for example, at a predetermined radial position which is equally divided from the center of the inner diameter of the diaphragm
Although the through holes 21 are formed, the positions of the through holes 21 may be randomly formed. The diameter of the through hole 21 is selected to be about 0.5 mmφ to 1 mmφ.

A cap 22 is formed on the upper end of the voice coil bobbin 11 or the inclined portion of the diaphragm 10 in a dome shape with a bonded portion 23 made of a highly airtight material such as aluminum. Are bonded via an adhesive so as to cover the surface.

Further, the sound from the diaphragm 10 which is formed in a funnel shape so as to cover the maximum outer diameter portion of the frame 8 so that the distance from the diaphragm is substantially constant is not radiated to the front surface. The airtight plate 24 made of synthetic resin or the like formed on the gasket 19
A predetermined airtight space 25 is formed between the airtight plate 24 and the vibration plate 10.

The tinsel wire 16 is connected to the voice coil 12, and an audio signal is supplied to the voice coil 12 via an input terminal 15 attached to the frame 8.

By assembling the small speaker as described above, the first space 20a and the second space 20b between the diaphragm 10 and the upper surface of the plate 5 are formed.

Further, as shown by a broken line in the center pole 6a or the yoke 6, a through hole 26a or 26b is formed as necessary, so that the first and second space portions 20a below the damper 17 are formed.
And 20b may be lowered to increase the low-range sound pressure level of the speaker device.

FIG. 2 shows a loudspeaker apparatus in which the loudspeaker 3 shown in FIGS. 1A and 1B is arranged in a loudspeaker box 1 having phase inversion type ducts 18 and 18b having the same configuration as that of FIG. 1 is a side sectional view of FIG. In FIG. 2, the speaker 3 has substantially the same configuration as that described in FIGS. 1A and 1B except that the through holes 26a and 26b are not formed in the center pole 6a and / or the yoke 6.
1A and 1B will not be described.

The above-mentioned speaker box 1 is made of ABS resin or the like and has a small and light weight of about 1 to 3 liters.
Assuming that the diameter of the speaker 3 is 8 cmφ or less, an acoustic signal is supplied from the terminal 13a to the voice coil 12, and when the speaker 3 is driven, the driving force F _{1 in the} F ₁ direction is applied to the diaphragm 10. M ₀ α ₀ and reaction force −F ₁ = M ₀ α
₀ works.

On the other hand, a plurality of through holes 21 formed in the diaphragm 10
Is n, the first formed on the front side of the damper 17 is
When the diaphragm 10 vibrates, air flows into the space 20a, and the pressure in the volumes of the first and second spaces 20a and 20b fluctuates.

Due to the air flowing into the first space 20a, an acting force F _D / n and a reaction force -F _D / n to the acting force are generated in the through hole 21 of the diaphragm 10.

Therefore, such F _D / n + F _D / n + ‥
‥ = When it ask balanced so as to be F ₁ using the two speakers 3 and 3b as described in FIG. 7 to cancel the reaction force -F ₁ and -F ₂ and reaction forces likewise -F ₁ - (F _D
/ N + F _D / n + ‥‥).

In the case of FIG. 2, the first duct 18 and the second duct 18b are used to
Duct emittance opening 18c of the second duct 18b to 8a of the duct radiation force F _D1 (or _{-F D1) F D2 / 2 +} F D2
/ 2 {or _{-F D2 / 2 + (- F} D2 / 2)} to F _D1 ≒ F _D2
Since / 2 + F _D2 / 2 that each other supported by canceling each other by, that as a condition for not swinging the speaker box 1 it is sufficient to satisfy _{F 1 ≒ F D / n +} F D / n as described above become.

The radiation force F _D / n of the air passing through the through hole 21 formed in the diaphragm 10 of the speaker 3 and the reaction force −F _D / n indicate the equivalent mass of the air due to the movement of the diaphragm 10. Assuming that M _A and the acceleration of the air passing through the through hole 21 is α _A , for example, the through hole 21 when the diaphragm 10 moves forward
If the radiation power of the air to be radiated becomes _{F D = M A · α A} , the total area of the hole 21 that the effective vibration area of the vibrating plate 10 bored in S _P · diaphragm 10 and S _A from, alpha _A = _SP / S
A _A · _{α A,} (density of ρ is air, a is the diaphragm effective _{radius) M A = 16/3 ·} ρa 3 because it is, radiation force F _D exerted on the through hole 21 can be easily determined.

Further, it is well known that the low-frequency characteristic of the vibration system of the speaker 3 is generally determined by Q _{0 at} f ₀ .

Now, let the effective mass of the vibration system of the speaker be M ₀ ,
The stiffness of the vibration supporting portion is S ₀ , the internal resistance of the output amplifier is R ₀ , the resistance of the voice coil is Rv, the length of the voice coil is Lv (cm), the mechanical resistance of the vibration system is Rm, and the internal volume of the speaker box is Assuming that the stiffness is Sc, the resistance in the speaker box is Ra, and the magnetic flux is Bg, Q ₀ can be expressed by the following equation (1).

As is clear from the above equation (1), when the diaphragm 10 is driven, a plurality of through holes 2 formed in the diaphragm 10 are formed.
Mechanical resistance Rm passing through the hole 21 through the 1 increases, (1) the denominator increases, it is clear that acts as reducing the value of Q _0.

Therefore, the transition of f _{0 to} the high frequency side can be prevented with the decrease of Q ₀ , the low frequency band is expanded, and a speaker device capable of radiating high quality low frequency band can be obtained.

In the loudspeakers shown in FIGS. 1 and 2, the airtight plate 24 is configured to completely cover the upper surface of the diaphragm 10, but FIG. 3 shows a relatively large through hole at the position of the airtight plate 24 opposed to the center position of the cap 22. 26 is the same as the speaker 3 described in detail in FIGS. 1 and 2. Condition to cancel or attenuate the reaction force -F ₁ for example acting force F ₁ of the diaphragm 10 by using a single speaker 3 in the case shown in FIGS. 1 and 2 _{F 1 ≒ (F D / n} + F D / N +
‥‥) to be selected, but acting force F _D3 and reaction force -F _D3 at the time of out incoming air during driving of the diaphragm 10 in the through hole 26 bored in the airtight plate 24 in the configuration shown in FIG. 3 occurs, relational expressions support each other at the time of driving of the speaker 3 to the acting force F _D3 or reaction force -F _D3 is taken into account is F ₁ + F _D3 ≒ (F
_By selecting _D / n + FD / n + ‥‥), the balancing condition at the time of design can be increased.

FIGS. 4 and 5 show still another embodiment of the loudspeaker of the present invention. In these cases, the loudspeaker 3 is joined to the upper part of the diaphragm 10 or the voice coil bobbin 11 with good airtightness. A cap formed of aluminum or the like in a dome shape has a double structure.

In the embodiment shown in FIG. 4, the first cap 22 is bonded via a bonding portion 23 so as to hermetically cover the upper surface of the voice coil bobbin 11, and a plurality of caps are provided at a diameter position larger than the outer diameter of the bonding portion 23. For example, n holes are bored at angular positions where the through holes 21 are equally divided by n from the center position of the diaphragm 10, and a predetermined gap L is provided between the through holes 21 and the first cap 22.
Is bonded to the diaphragm 10 via the bonding portion 23, and a plurality of through holes 21 formed in the diaphragm 10 are arranged between the first and second caps 22 and 27. I have.

Further, a single through hole 28 is formed at the center position of the second cap 27.

[0053] balance of order to cancel or attenuate the reaction force -F ₁ to the action force F ₁ of the example diaphragm 10 when disposed a speaker 3 for the arrangement in FIGS. 1 to 3 in the same manner as the speaker box 1 conditions the radiant power of the through hole 28 portion bored in the second cap 27 and F _D4 and -F _D4, the radiant power of the hole 21 bored in the diaphragm 10 F _D / n and -F _D / F ₁ ＦF _D4 + (F _D / n + F _D / n
+ ‥‥) is satisfied, and a force for supporting the reaction force −F ₁ can be provided in the speaker 3.

In the embodiment of the invention shown in FIG. 5 having the same concept, the first cap 22 has the same structure as that of FIG.
Is formed with one through hole 29 at the center. In this case, when a material such as a synthetic resin is applied to the damper 11 by selecting a material having high airtightness, the air radiated through the through hole 29 into the small volume of air in the second space 20b. balance equation because it is possible to add a radiation force F _D5 and reaction force _{-F D5 F 1 ≒ F D4 +} (F D / n + F
_{D / n + ‥‥) + F} D5 that it can be.

In the above-described embodiment, the case where the airtight plate 24 is formed in a funnel shape having substantially the same shape as the diaphragm 10 has been described.
The speaker sound emission hole 2a formed in the baffle board 2 of the speaker box 1 is closed, and the volume of air in the space formed between the speaker box 1 and the diaphragm 10, that is, the stiffness S _C1
May be increased.

[0056]

According to the loudspeaker apparatus of the present invention, a simple structure in which a single loudspeaker unit is used, a plurality of through holes are formed in the diaphragm, and an airtight plate is provided, so that a reaction force against the acting force at the time of driving the diaphragm is obtained. By canceling or attenuating the force, a speaker device capable of emitting sound by expanding a low range without swinging a small and lightweight speaker device can be obtained. Moreover, the lowest resonance frequency f in the resonance sharpness Q low resonance frequency f ₀ and the value can be reduced only drilling a hole in the diaphragm of ₀ to _0, according to the speaker of the present invention the low frequency side Can be changed to Furthermore,
A speaker device capable of attenuating the reaction force of the speaker can be obtained by simply arranging one speaker having a through hole in the diaphragm in the speaker box.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a speaker of the present invention.

FIG. 2 is a side sectional view of the speaker device of the present invention.

FIG. 3 is a side sectional view of another speaker of the present invention.

FIG. 4 is a side sectional view (I) of still another speaker of the present invention.

FIG. 5 is a side sectional view (II) of still another speaker of the present invention.

FIG. 6 is a sectional view of a conventional speaker device and an electric equivalent circuit diagram thereof.

FIG. 7 is another side sectional view showing the configuration of a conventional speaker device.

[Explanation of symbols]

1 speaker box, 3, 3b speaker, 10
{Vibration plate, 17} Damper, 18, 18b} Duct, 21, 28, 29 {Hole, 22, 27} Cap

Claims (4)

[Claims] An airtight plate is provided on a front surface of a diaphragm to reflect the sound of the diaphragm into a speaker box, and a through hole is formed in the diaphragm or cap facing the airtight plate. Speaker device. 2. The speaker device according to claim 1, wherein a through hole is provided in the airtight plate. 3. The cap has a double structure including an upper cap and a lower cap, and a through hole is formed in an upper cap of the double-structured cap, and a diaphragm between the upper cap and the lower cap is provided on the diaphragm. 2. The speaker device according to claim 1, wherein the speaker device is formed with a through hole. 4. The speaker device according to claim 3, wherein a through hole is formed in the lower cap.