JP2000050384A - Speaker device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compact and lightweight speaker device capable of extending reproduction of low frequencies and reducing distortion by opposing a diaphragm in a speaker unit to a sound discharging hole in a speaker box and arranging a passive radiator on the back of the magnetic circuit. SOLUTION: In order to function a rear board 35 of the speaker box 21 which is opposed to a shield case 43 of a magnetic circuit 27 in the speaker unit A as a passive radiator, the rear board 35 constitutes the passive radiator as a drawn cone of a circle or the like having a prescribed diameter by forming plural flexible parts 46 on the board 35 based on the approximately center position of the circuit 27 as a reference and each flexible part 46 forms a spring part for applying prescribed stiffness. The speaker unit A is fixed on the speaker box 21 through a frame 5 oppositely to the sound discharging hole 26 formed on a buffle board 22 of the speaker box 21. Thereby the reaction force -FD1,-FD2 of duct radiation force FD1, FD2 between ducts 44, 45 are mutually offset.

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 in which the bass sound pressure of a speaker unit is increased and the influence of the reaction force of a speaker box is reduced.

[0002]

2. Description of the Related Art Conventionally, in order to suppress vibration of a baffle board of a speaker box in which a speaker unit is mounted, a vibrator that vibrates in a direction opposite to a vibration direction of a speaker vibrated by a diaphragm. Alternatively, a speaker device having a transducer is disclosed in, for example, JP-A-63-21.
No. 2000, JP-A-1-307398, and the like.

The above-mentioned Japanese Patent Application Laid-Open No. 63-212000 discloses a speaker device as shown in FIG. In FIG. 3, reference numeral 1 denotes a ring-shaped magnet, and reference numerals 2 and 3 denote a plate and a yoke which are attached so as to sandwich the magnet 1 and partially have a magnetic gap 4 formed therein. Plate 2
Is mounted with a frame 5 of the speaker unit A, and an outer edge of the frame 5 is provided with an edge 6.
The outer periphery of the cone-shaped diaphragm 7 is held by the edge 6.

On the other hand, a voice coil bobbin 8 is mounted on the inner peripheral portion of the diaphragm 7, and a voice coil 9 is wound around the voice coil bobbin 8, and the voice coil 9 is formed by the plate 2 and the yoke 3. Magnetic gap 4
Is inserted inside. The configurations indicated by the reference numerals 1 to 9 are the basic structure of the well-known electrodynamic speaker unit A.

One end of a screw 10 is screwed into the center of the back surface of the yoke 3 of the speaker unit A. The other end of the screw 10 is completely connected to the magnet 1, plate 2 and yoke 3 of the speaker unit A. A magnetic circuit composed of a magnet 11, a plate 12, and a yoke 13 having the same configuration is mounted.

[0006] A frame 14 is mounted on the plate 12, and two dampers 15, 16 are mounted on the frame 14.
The drive coil bobbin 17 is held by 5 and 16.

A drive coil 18 is wound around one end of the drive coil bobbin 17, and the drive coil 18 is provided with a magnetic air gap 1 formed by the plate 12 and the yoke 13.
9 is inserted. A weight 20 is attached to the other end of the drive coil bobbin 17, and the vibration system including the weight 20 is substantially equal to the equivalent mass of the vibration system including the cone-shaped diaphragm 7 and the like in the speaker unit A. It has been made to. The configuration indicated by the reference numerals 11 to 20 indicates the electric / vibration transducer B.

In the above configuration, the speaker unit A and the electric / vibration transducer B are connected to the speaker box 2
It is attached to one baffle board 22. Now, the voice coil 9 causes a driving force F ₁ vibrates in the horizontal direction in the figure by a known action if energizing electrical signal to the voice coil 9 of the speaker units A, sound reproduction by driving the diaphragm 7 of the cone type I do.

At this time, the electric / vibration transducer B
The application of a same electric signal to the driving coil 18 in the driving coil 18 also vibrates in the horizontal direction in the figure driving force F ₂
And the weight 20 is driven in the same direction. Here, if the equivalent mass of the vibration system including the diaphragm 7 and the like in the speaker unit A and the vibration system including the weight 20 and the like in the electric / vibration transducer B are substantially equal, the reaction force −F _{1 received} by the speaker unit A by the vibration system. And electricity
Reaction force -F of vibration system in vibration transducer B
₂ is almost equal.

Accordingly, the reaction of the speaker unit A due to the driving of the diaphragm 7 is canceled by the electric / vibration transducer B, and the vibration of the baffle board 22 of the speaker box 21 and the swing of the speaker box 21 are suppressed. .

On the other hand, there is a demand to obtain an inexpensive speaker system by reducing the volume of the speaker box 21 and miniaturizing it. In general, however, the volume of the speaker box 21 is reduced. Therefore, the amplitude of the speaker unit A is increased to suppress an increase in the low-frequency reproduction limit.

However, by increasing the amplitude of a small loudspeaker, the sound pressure in the loudspeaker box 21 increases, and peaks and valleys occur in the frequency characteristics. As a method for solving such a problem, a speaker device which uses a speaker box provided with a flush radiator to effectively utilize sound waves emitted from the back of a diaphragm of a speaker unit to radiate a low-frequency range without distortion. Is also widely used.

Furthermore, the action force F ₁ of the diaphragm 7 of the first speaker unit A in JP-A 1-307398 discloses that the aforementioned towards the cone opening of the diaphragm 7 of the two speaker units A in the opposite direction It is also a reaction force -F ₁ arising speaker apparatus to cancel reaction force -F ₂ acting force F ₂ of the diaphragm 7 of the second speaker units a disclosure.

According to the conventional speaker device, the acting force F ₁ = M applied to the diaphragm of the first speaker unit A
₁ · α ₁ (where M ₁ is the equivalent mass of the vibration system, α ₁ is the acceleration of the diaphragm) is the reaction that occurs in this rigid body when the magnetic circuit, the frame of the speaker unit and the speaker box are assumed to be one rigid body force -F ₁ = M ₁ '·
α ₁ ′ (where M ₁ is the equivalent mass of the above-mentioned rigid body, α ₁ ′ is the acceleration given by the reaction).

Accordingly, the acceleration α ₁ ′ given by the reaction force is the displacement of the reaction force −F ₁ determined by α ₁ ′ = − (M ₁ / M ₁ ′) · α ₁か ら (1) from the above equations. However, if M ₁ = ∞, there is no effect of the reaction force, and the diaphragm changes only by the acceleration applied to the voice coil, but actually M ₁ ′
Is finite. In particular, as described above, the entire speaker device including the speaker box is reduced in weight and size, the diaphragm becomes heavier, and the mass ratio M ₁ / M ₁ ′ tends to increase. low efficiency of regeneration for reaction force -F ₁ to the action force F ₁ of greatly reduced.

Further, actually, the magnetic circuit, the speaker frame, and the speaker box are not one rigid body, but each have a resonance point, and output the acoustic energy other than the reproduced sound as distortion by the energy given by the reaction. This causes a decrease in the fidelity of the output with respect to the input signal of the reproduced sound. As described above, such an adverse effect can be canceled by the two speaker units or the speaker unit and the electric vibration transducer. However, these configurations require two magnetic circuits and two voice coils, and require two drive circuits. This not only increases power consumption, but also increases the distance between the baffle board and the back plate of the speaker box, making it difficult to obtain a compact speaker device.

The present applicant has previously proposed a speaker device as shown in FIG. 4 in order to solve the above-mentioned problem. FIG.
Parts corresponding to those of the speaker device shown in FIG. 3 are denoted by the same reference numerals, and redundant description is omitted.

FIG. 4 is a side sectional view of the speaker device.
3 indicates such a small speaker unit as a whole,
The yoke 3 is made of a plate material such as pure iron and has a cylindrical bottom with a bottom section. The bottom has a center pole 24 having a center hole and an upwardly convex shape to reduce the weight.
A magnet 1 magnetized with an N-pole and an S-pole magnetized in the thickness direction of a light-weight ring-shaped plate in the form of a plate is bonded on the magnet 4 via an adhesive or the like. 25 are bonded via an adhesive or the like. The magnetic gap 4 is formed between the outer diameter of the pole piece 25 and the inner diameter of the cylinder forming the yoke 3.

The frame 5 has an opening having an inside diameter substantially the same as the diameter of the sound emission hole 26 formed in the baffle board 22,
In the depth direction of the speaker box 21, three steps 28a,
28b and 28c are formed, and are formed of a steel material or the like in a substantially funnel shape so that the opening of the step portion is gradually reduced in diameter.

A magnetic circuit 27 formed by the magnet 1, the yoke 3, the center pole 24 and the pole piece 25
Is suspended on the frame 5 by two corrugated ring-shaped second and third dampers 15 and 16. That is, the dampers 16 and 1 are attached to the bottom of the frame 5 and the third step portion 28c.
5 and the inner diameters of the dampers 16 and 15 above and below the cylindrical part of the yoke 3 of the magnetic circuit 27.

Further, the voice coil 9 wound around the voice coil bobbin 8 is inserted into the magnetic gap 4 of the magnetic circuit 27, and the voice coil 9 is suspended on the frame 5 by a corrugated ring-shaped first damper 29 joined to the upper part of the voice coil bobbin 8. It is made to do.

That is, the voice coil bobbin including the voice coil 9 is formed by joining the inner diameter of the first damper 29 to the outer diameter of the upper end of the voice coil bobbin 8 and joining the outer diameter to the second step 28b of the frame 5. 8 can swing freely in the longitudinal direction of the voice coil bobbin 8 within the magnetic gap.

The inner diameter of the funnel-shaped first diaphragm 7 is joined to the outer diameter of the upper end of the voice coil bobbin 8 with an adhesive or the like, and a ring-shaped edge 6 is formed on the outer periphery of the first diaphragm 7. The outer periphery of the edge 6 is joined to the first step 28a of the frame 5 via an arrow.

Further, a concave dust cap 3 is formed on the inclined portion of the first diaphragm 7 so as to cover the upper portion of the voice coil bobbin 8.
2 are joined.

A second diaphragm 30 is fixed to the bottom of the magnetic circuit 27 so that the funnel-shaped openings face in opposite directions so as to face the first diaphragm 7.

In FIG. 4, the bottom of the funnel-shaped diaphragm 30 is fixed to the bottom of the yoke 3 with screws 34 via a disk 33.

As described above, the first and second diaphragms 7 and 3
A speaker unit 23 composed of one magnetic circuit 27 and one voice coil 9 attached so that the opening of 0 faces in the opposite direction faces the sound emission hole 26 formed in the baffle board 22 of the speaker box 21. And fix it.

The first step 28a of the frame 5 of the speaker unit 23 is connected to the baffle board 2 via the screw 36.
Fix inside 2.

Further, the free edge of the edge 31 of the second diaphragm 30 is provided outside the ring-shaped fixing plate 38 fixed to the sound emitting hole 37 formed in the back plate 35 at a position facing the sound emitting hole 26 with a screw 36. The outer peripheral portions in the state are joined to form the speaker device 40.

With such a configuration, if an acoustic signal is supplied to the voice coil 9, F ₁ = M ₁ is applied to the first diaphragm 7.
・ Reaction force received when α ₁ acting force works-F ₁ = M
Only minute ₁ '· _{α 1'} second diaphragm 30 including the magnetic circuit 27 is caused to undergo displacement in the opposite direction.

[0031] Thus, the second diaphragm acoustic energy which acts as a reaction force -F ₁ not only can avoid the influence of the reaction force -F ₁ applied to the magnetic circuit 27 was cause of distortion in the conventional configuration Since the sound can be emitted through the line 30, the electric-acoustic conversion efficiency can be improved. Further, since the speaker box 21 is not affected by the reaction force −F ₁ ′ of the first diaphragm 7, it is not necessary to increase the equivalent mass of the speaker device 20 including the speaker box 21, and the depth becomes thinner. In addition, the size and weight can be reduced as in a book shell type speaker device.

[0032]

According to the speaker unit 23 having the structure shown in FIG. 4, the second diaphragm 30 including the magnetic circuit 27 is provided on the frame 5 by the two second and third dampers 15 and 16. Therefore, there is a problem that many parts are required when one speaker unit is formed, and assembly is complicated.

An object of the present invention is to provide a speaker device which has solved the above-mentioned problems. An object of the present invention is to provide a speaker system which is easy to assemble with a simple speaker configuration, and has a low depth direction. It is possible to obtain a compact and lightweight speaker device that can be narrower, improve the electro-acoustic conversion efficiency, effectively use the reaction force against the operation force of the diaphragm, expand the low-frequency reproduction, and reduce distortion. It is assumed that.

[0034]

A speaker according to the present invention faces a speaker sound emission hole formed in a baffle board of a speaker box, a diaphragm of a speaker unit faces a speaker board, and a flush pad on a back surface of a magnetic circuit of the speaker unit. A radiator is provided.

According to the loudspeaker device of the present invention, by arranging the flush radiator serving as the second diaphragm on the back of the loudspeaker unit, the loudspeaker unit can be simplified and the assembling into the loudspeaker box becomes extremely easy. The speaker unit can be reduced in size, the electric-to-acoustic conversion efficiency can be improved, and the reaction force of the diaphragm can be offset by one magnetic circuit, one voice coil and one drive source speaker unit, and It is possible to reduce the depth of the box between the baffle board and the back plate and reduce the size of the box.

[0036]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a speaker device according to the present invention.
An embodiment will be described with reference to FIGS. Note that the same reference numerals are given to portions corresponding to the speaker device shown in FIG.

The speaker unit A used in FIG. 1 may be a speaker unit having exactly the same structure as that described in detail in FIG. 3, but in FIG. 1, the speaker unit A has a magnetically shielded speaker unit structure. That is, the driving magnet 1 is provided on the back side of the yoke 3.
The cancel magnet 42 magnetized in the thickness direction opposite to the magnetizing direction is joined via an adhesive, the magnetic circuit 27 is surrounded by the cup-shaped shield case 43, and the outer circumference of the plate 2 and the inner diameter of the shield case 43 are A normal magnetically shielded speaker unit A is configured so that a magnetically closed circuit is formed so as to be in contact with the magnetic flux so that the magnetic flux does not cross outside.

The rear plate 35 of the speaker box 21 which faces the shield case 43 of the magnetic circuit 27 of the speaker unit A has a substantially central position of the magnetic circuit 27 in order to function as a flush radiator (passive radiator). As a reference, the back plate becomes a flush radiator by forming a circular, square, rectangular or the like drone cone having a flexible portion 46 provided on the back plate 35, and the flexible portion 46 provides a spring portion that provides a predetermined stiffness. Will be formed.

Further, the speaker unit A is fixed in the speaker box 21 via the frame 5 so as to face the sound emission hole 26 formed in the baffle board 22 of the speaker box 21.

Below the sound output hole 26 to which the speaker box A is attached, first and second ducts 44 and 45 constituting a phase inversion type speaker box are arranged concentrically.

That is, of the first and second ducts 44 and 45, the first duct 44 and the opening 44 of the duct are provided.
a is molded integrally with the baffle board 22.

Further, a second duct 45 having a larger duct diameter than the first duct 44 is provided on the back plate 35.
Are formed so as to overlap and have a concentric cross section within a predetermined length, and are erected integrally with the back plate 35 and radiated to the opening 44a of the first duct 44 through the opening 45a of the second duct 45. equivalent mass M _D and the equivalent resistance R of air
_D is enlarged to form a bent duct.

The reaction forces -F _D1 and -F _D2 ducts radiation force F _D1 and F _D2 between the speaker box 21 configured as described above the first duct 44 and second duct 45 is mutually canceled, lightweight The speaker box 21 has a duct opening 44a.
Never swings back and forth by the air emitted radiation action force at the time of F _D1 and reaction force -F _D1 from and when viewed as a speaker box 21 since the mutually balanced between the second duct 45 speaker Actuation force F of unit A when emitting sound
_What is necessary is just to consider the balance with reaction force -F1 with respect to ₁ .

According to the speaker device 40 having the configuration shown in FIG. 1, the speaker unit A fixed in the speaker box 21
When the is driven, the sound radiation force is F ₁ = M ₁ · α as described above.
It is given by _1. Naturally reaction force -F ₁ of this sound radiation force is generated.

[0045] Thus, Pash blanking radiator 30 in this reaction force -F ₁ results in a radiation force F ₂ of the air, of course generates the reaction force -F _2.

Now, the equivalent mass of the flush radiator 30 is M ₂ , the acceleration applied to the flush radiator 30 is α ₂ , and the compliance (spring constant) is K.
Then, the speaker unit A is driven to emit the sound radiation force F ₁
= The reaction force when the acting force of M ₁ · α ₁ acts on the diaphragm 7-F ₁ as the exciting force, and the flush radiator 30
₂ = M ₂ · α ₂ acting force. At this time, naturally -F ₂
= M ₂ α ₂ reaction force acts.

Accordingly, the reaction force -F ₁ of the acting force F ₁ when the speaker unit A emits sound and the flush radiator 3
The reaction force −F ₂ of the sound radiation force F ₂ of 0 can be canceled or attenuated by setting F ₁ ≒ F ₂ .

Therefore, F ₁ ≒ F ₂ , M ₁ · α ₁ ≒ M ₂ ·
Since in alpha _2, M ₂ in the selection of alpha ₂ has become a properly selected, can be selected to M ₂ = M ₁ For example, if the α ₁ = α _2.

Further, the described ash radiator 30
The resonance frequency f ₀₂ of is obtained as (2). Therefore, by selecting this value between the lowest resonance frequency f ₀ of the speaker unit A and the resonance frequency f _D0 of the duct generated by the duct, the low-frequency sound pressure is emphasized without lowering the low-frequency reproduction frequency. It is possible to do. In this case, it is more effective to match the resonance frequency f ₀₂ of the flush radiator 30 with the lowest resonance frequency f ₀ of the speaker unit A.

In the configuration shown in FIG.
A speaker unit cancel or attenuate possible action force -F ₁ of reaction forces A F together with the functioning of the back plate 35 of the speaker box 21 as back Shiv radiator in the usual manner in order to not put the baffle board 22 side ₂ can be generated.

The flexible portion 46 is formed such that corrugations are formed at the time of molding the speaker box 21 or the back plate 35 so as to be thin, or the edges of a synthetic resin or the like having a corrugated shape are formed similarly to the free edges. May be stuck between the outer peripheral portion of the base plate and the back plate 35.

FIG. 2 shows another embodiment of the speaker device of the present invention. The speaker unit A has the same configuration as that of FIG. 3, and the configuration of the first and second ducts 44 and 45 that constitute the double duct of this example is disposed opposite to the baffle board 22 and the back plate 35, and The radiator 30 includes a back plate 35 and a magnetic circuit 27 of the speaker unit A.
This is a case in which it is provided on the middle plate 49 interposed between the back surfaces of the above.

In the speaker box 21 of the present embodiment, a middle plate 49 is provided between the top plate 22U and the bottom plate 22D so that the volume of the speaker box 21 becomes approximately half, and this middle plate 49 is provided with a predetermined stiffness (spring constant K). The flexible portion 46 is formed of synthetic resin (ABS) or the like into a corrugated thin shape like a corrugation, for example, into a circular or square shape.
Is configured.

Further, a duct opening 45 is formed in the back plate 35 facing the first duct 44 provided on the baffle board 22.
The second duct 45 is formed integrally with the back plate 35 by drilling a.

Even in the speaker device 40 having the configuration shown in FIG. 2, the reaction force −F of the sound radiation force F ₁ of the speaker unit A is obtained.
By _1, the action force F ₂ to generate a reaction force -F ₁ as an excitation source Pash Bed radiator 30 is a drawn cone in the middle plate 49. Further, Pash blanking as the equivalent circuit of the radiator 30 the compliance C ₂ of the flexible portion and the equivalent mass M ₂ and the equivalent resistance R ₂ of the drawn cone portion are connected in series, in order to be coupled to the equivalent circuit of the speaker unit A An acting force indicated by F _D3 is also generated. Therefore, the reaction force -F ₂ = - against reaction force -F ₁ of _{(M 2 · α 2 + F} D3) speaker units _{A, -F 1 ≒ -F 2 -} (M 2
· Α ₂ + F _D3) and the reaction force -F ₁ by sound radiation force F ₁ of the speaker unit A when as made are canceled or attenuated and the working force F ₂ of Pash blanking radiator 30.

In the case of FIG. 2, the first and second ducts 4 are also provided.
Since by that emit 4 and 45 in the opposite direction F _D1 = F _D2 are mutually balanced by -F _D1 and the -F _D2 immediately canceled or attenuated to it can be a duct section so true speaker units A and Passhubu Only the balance relationship with the radiator 30 needs to be considered.

Now, assuming that the equivalent mass of the flush radiator 30 is M ₂ , the effective area is S _D3 , the acceleration acting on the drone cone (the flush radiator not including the flexible portion 46) is α ₂ , the acceleration acting on the flush radiator 30 Is α _D3 , the above acting force F _D3 is Here, S is the effective area of the diaphragm 7 of the speaker unit A.

Therefore, in order to make -F ₁ ≒ -F ₂ , it is sufficient to satisfy the expression (3). If −F ₂ ≧ −F ₁ , the value of −F ₁ − (− F ₂ ) is added to the sound radiation force F ₁ of the speaker unit A, and a very powerful low sound can be emitted.

The reason why F ₂ is added to F ₁ is as follows.
Since α _D3 = S / S _D3 · α ₁ , F ₁ = M ₁ · α ₁ =
It can be obtained from M ₂ · α _{2 as} α ₂ = M ₁ / M ₂ · α ₁ . It will be added to the sound radiation force F ₁ of the speaker unit A acting force F ₂ of the radiation of _{M 2 · S / S D3 ·} α 1 only Pash Bed radiator 30 because it is increased.

[0060]

According to the speaker device of the present invention, a flexible portion and a predetermined equivalent mass and equivalent resistance are imparted to the back plate of the speaker box, and the speaker plate is swingably disposed on the rear surface of the speaker unit. A speaker device that can function as a flush radiator, can increase low-pitched sound pressure, and supports a reaction force of sound radiation force of a speaker unit and does not swing a lightweight speaker box can be obtained. In addition, by functioning as a flush radiator, it is possible to provide a speaker device in which the bass sound radiation effect is enhanced.

[Brief description of the drawings]

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

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

FIG. 3 is a partial sectional view of a conventional speaker device.

FIG. 4 is a side sectional view of a conventional speaker device.

[Explanation of symbols]

A speaker unit, 7 diaphragm, 21 speaker box, 22 baffle board, 27 magnetic circuit, 30 flush radiator, 35 back plate, 40 speaker device

Claims (3)

[Claims] A radiator for a speaker unit is opposed to a speaker sound emission hole formed in a baffle board of a speaker box, and a flush radiator is provided on a back surface of a magnetic circuit of the speaker unit. A speaker device characterized by the above-mentioned. 2. The speaker device according to claim 1, wherein a flexible portion is provided on a back plate of a speaker box facing a back surface of a magnetic circuit of the speaker unit, thereby forming the flush radiator. 3. The loudspeaker device according to claim 1, wherein an intermediate plate is provided on a back surface of the magnetic circuit of the speaker unit, and a flexible portion is provided on the intermediate plate to form the flush radiator. .