CN102281488A - Double-transduction-mode combined coaxial full-range loudspeaker - Google Patents

Abstract

The invention discloses a double-transduction-mode combined coaxial full-range loudspeaker. The double-transduction-mode combined coaxial full-range loudspeaker comprises a magnetic circuit structure, wherein a voice coil is arranged on the upper part of the magnetic circuit structure; a vibrating plate is arranged at the output end of the voice coil; the vibrating plate is a wafer made of a piezoelectric material; and the wafer is fixed on the magnetic circuit structure through a folded ring and a gasket. An electric loudspeaker is combined with a piezoelectric loudspeaker; a transduction device, namely a piezoelectric wafer of the piezoelectric loudspeaker serves as a vibrating plate (a conical basin) of the electric loudspeaker; and the coaxial full-range loudspeaker works in an electric transducer mode at a low frequency range and works in a piezoelectric transducer mode at a high frequency range, so that a novel, unique and combined full-range loudspeaker is formed. The double-transduction-mode combined coaxial full-range loudspeaker can work at a full frequency range on the premise of not increasing volume and not increasing devices such as a frequency divider and the like. The double-transduction-mode combined coaxial full-range loudspeaker can be widely applied in the field of loudspeakers.

Description

A kind of pair of transducing mode combination coaxial full frequency speaker

Technical field

The present invention relates to a kind of loud speaker, a kind of pair of transducing mode combination coaxial full frequency speaker especially, the described pair of transducing mode combination coaxial full frequency speaker are the brand-new energy transducer with piezoelectric transducer and dynamic transducer hybrid working.

Background technology

Piezoelectric transducer spare (loud speaker) is characteristics of utilizing piezoelectric material production mechanical deformation under electric field action at present, reaches the transducing effect of electricity → sound.The size of its distortion is directly proportional with electric field strength.

Piezoelectric ceramic has piezoelectricity, can produce extra electric charge when promptly exerting pressure.Piezoelectric effect has reflected the elastic performance of crystal and the coupling between the dielectric property.Piezoelectric equations then reflects the elastic module (being stress, strain) of piezoelectric ceramic and the relation between the electricity variable (being electric field and electric displacement).

The piezoelectric in past is because majority is piezoelectric ceramic class material (barium titanate series, lead titanates system, niobate, lead zirconate titanate system etc.), because of the characteristics of its material: frangible, be difficult for producing than great, bigger sheet material.In the electro-acoustic element practical application, majority applies to small-sized electro-acoustic transducer device (loud speaker).Usually the high band, the supersonic range that only are applied to audio frequency are used (for example: tweeter, buzzer, supersonic generator etc.) as microphone device.This is the characteristics (the more little capacitive reactances of device is high more) because of the capacitive reactances of material own, and frequency is high more, and conversion efficiency is also high more.And very high because of its impedance in the low-frequency range of audio frequency, conversion efficiency is extremely low, works hardly.

Therefore, the use in the audio frequency field has certain limitation.

At present because the appearance of macromolecular compound Kynoar PVDF material, with respect to piezoelectric ceramic class material, have non-friable, proportion is less, mechanical strength is high, can produce the sheet material, tubing of multiple shape, different-thickness (thinner, lighter) etc.(the material attenuation, surface area increases, and capacitive reactances can reduce, and lower frequency range conversion efficiency meeting improves, the high band influence is less).

This is the practical application of piezoelectric in electro-acoustic element, has opened up brand-new thinking.

And dynamic transducer (loud speaker) is used having quite widely of electroacoustic field.When device had requiring of miniaturization, dynamic transducer (loud speaker) overall dimension was more and more littler.But because of the relation of the transduction principle of dynamic transducer (loud speaker), in the time of miniaturization, swept area is also reducing, and the quality of oscillating component is also reducing.The resonance frequency of loud speaker can improve accordingly, and the overall work frequency range will be to high frequency offset.

On the contrary, when dynamic transducer (loud speaker) size was big, the resonance frequency of loud speaker can reduce accordingly, and the overall work frequency range will be offset to low frequency, and the operating efficiency of high band can sharply descend.

For satisfying the requirement of full range band work, the dynamic transducer (loud speaker) of different size (large and small) need be combined into the full range speaker system by frequency divider.

Industry often adopts the frequency division mode, with two or more dynamic transducers (loud speaker), is combined into the loud speaker of full range band work.Make it by frequency divider: one focuses on low-frequency range work, and one focuses on high band operation.But this has caused new problem again: one, increased the frequency division device, and two, increased numbers of transducers, total volume is increased.

Perhaps, add a piezoelectric transducer spare (loud speaker), be combined into the loud speaker of the full range band work of two transducing form combinations at dynamic transducer (loud speaker).May save the frequency division device like this, but volume has strengthened still.

Importantly, the problem of how to arrange on the mode of these two (or three) assembling devices does not solve.

A kind of method for combining and arranging commonly used is: two devices are arranged side by side, will increase volume like this, increase surface area.

Another kind of assembled arrangement mode commonly used is: two forward and backward arrangements of device.Such combination, the device of front will stop the acoustic radiating of back device.

More than during two kinds of method for combining and arranging, also can near part-frequency point, will work simultaneously because of two acoustic radiating sources, cause near part-frequency point, the sound wave of two sound source radiations, the distance that arrives the hearer is different, thereby can cause sound wave to interfere (offsetting) mutually with phase time stack, when anti-phase, influence the equilibrium that the whole system sound wave is exported.

Summary of the invention

The technical problem to be solved in the present invention is: a kind of full frequency speaker is provided, and described loud speaker is not additionally increasing under the situation of loud speaker volume and device, can guarantee the full range band work of loud speaker.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A kind of pair of transducing mode combination coaxial full frequency speaker, comprise magnetic structure, described magnetic structure top is provided with voice coil loudspeaker voice coil, the output of described voice coil loudspeaker voice coil is provided with oscillating plate, the disk of described oscillating plate for adopting piezoelectric to make, described disk is fixed on the magnetic structure by ring and packing ring or by support.

Be further used as preferred embodiment, described piezoelectric is piezoelectric ceramic class material and/or fluorine-containing plastics piezoelectric.Described piezoelectric ceramic class material is barium titanate series, lead titanates system, niobate or lead zirconate titanate system.Described fluorine-containing plastics piezoelectric is macromolecular compound Kynoar PVDF material or other similar material.

Be further used as preferred embodiment, described disk and ring are circle, ellipse, runway shape, square or accurate square.

Be further used as preferred embodiment, described voice coil loudspeaker voice coil further is fixed on the position relative with magnetic structure by centring disk.

Be further used as preferred embodiment, described centring disk adopts packing ring or support to be fixed on the magnetic structure

Be further used as preferred embodiment, described centring disk is soft certain flexible material formation that has.

Be further used as preferred embodiment, described magnetic structure is external magnetic type structure or internal magnetization structure.

The invention has the beneficial effects as follows: the present invention is by making up dynamic speaker and piezoelectric speaker, the oscillating plate (vibrating diaphragm, awl basin) of the energy transducer-piezoelectric disc of piezoelectric speaker as dynamic speaker, work in the dynamic transducer mode in the low frequency frequency range, work in the PZT (piezoelectric transducer) mode in high-frequency band, constitute a kind of novel, unique composite type full frequency speaker, described loud speaker can not increase volume, does not increase the full range frequency range work that realizes loud speaker under the prerequisite of devices such as frequency divider; The disk that the present invention adopts piezoelectric to make is replaced the oscillating plate (awl basin, tapered oscillating plate) of traditional dynamic transducer (loud speaker), has increased the quality of loudspeaker vibration part, has improved the low frequency characteristic of loud speaker; The sound source of loud speaker of the present invention comes from same oscillating plate, and not only coaxial but also same sound source has been avoided acoustic interference.

Description of drawings

Below in conjunction with accompanying drawing the specific embodiment of the present invention is described further:

Fig. 1 is the structural representation of existing electrodynamic type cone loudspeaker;

Fig. 2 is the reactance analogy equivalent electric circuit of dynamic speaker;

Fig. 3 and Fig. 4 are the admittance analogy equivalent electric circuits of low frequency frequency range dynamic speaker;

Fig. 5 is a piezoelectric speaker reactance analogy equivalent electric circuit;

Fig. 6 is the loadspeaker structure schematic diagram of external magnetic circuit structure of the present invention;

Fig. 7 is the loadspeaker structure schematic diagram of internal magnetic type magnetic line structure of the present invention;

Fig. 8 and Fig. 9 are the structural representations of disk of the present invention, ring, voice coil loudspeaker voice coil, centring disk;

Figure 10 is the structural representation of external magnetic circuit structure;

Figure 11 is the structural representation of internal magnetic type magnetic line structure.

Embodiment

The coaxial full frequency speaker of the present invention utilizes piezoelectric transducer spare (loud speaker) to be operated in the characteristics of high band, utilize dynamic transducer spare (loud speaker) again when having increased resonance mass, the characteristics that low-frequency cut-off frequency reduces, characteristics in conjunction with the emotional resistance of the capacitive reactances of piezoelectric transducer spare and dynamic transducer spare, can reach loud speaker needn't increase volume, increase under the prerequisite of frequency division device, in the purpose of full frequency band operate as normal.

With reference to Fig. 1, the electrodynamic type cone loudspeaker comprises magnetic structure 1, and described magnetic structure 1 is made of magnet steel 11 and inner magnetic core 12, and described magnetic structure 1 is provided with voice coil loudspeaker voice coil 2, and the output of described voice coil loudspeaker voice coil 2 is connected with awl basin (tapered oscillating plate) 7.

Tone currents and the permanent-magnetic field interaction of flowing through voice coil loudspeaker voice coil in the magnetic field can produce the power that the awl basin axially drives.This active force can be formulated:

F＝BLI (N) (1-1)

B in the formula---the magnetic flux density (T) in the magnetic air gap; The effective length (m) of L---voice coil loudspeaker voice coil lead; The electric current of I---flowing through voice coil (A).

Under this active force, the awl basin will move as an integral body (piston), but only before a certain critical frequency.The frequency range of this mass motion often is called as the piston vibration scope of boring basin.

As all electroacoustic transducers, loud speaker also can be expressed as the four-terminal network form of electricity input and mechanics output.With reference to Fig. 2, it is 1 that four-terminal network can be regarded transformation ratio as: the transformer of BL.Here, BL is called as the electric power coupling coefficient.

The left side (electric) part of reactance analogy equivalent electric circuit comprises amplifier, voltage U and voice coil loudspeaker voice coil resistance R e, the voice coil loudspeaker voice coil inductance L e of band internal resistance Rg.The right (mechanics) part comprises the mechanical loss resistance R _MS, radiation impedance R _MR, the compliance C of support system _MS, the mass M of vibrational system _MS(by cone rest mass M _C, the voice coil loudspeaker voice coil mass M _VThe M that forms _MDWith air servo-actuated mass M _AConstitute).

The work of loud speaker can be described with two equations:

1, the electric part of equivalent electric circuit

U＝IZ _e+BLX(V) (1-2)

Z in the formula _e---the all-in resistance of voice coil loudspeaker voice coil is anti-, Z _e=R _e+ j ω L _e(Ω);

ω---angular frequency, ω=2 π f (rad/s), f is frequency (H _Z);

Attention: why relevant with frequency the soluble loudspeaker impedance of this formula is.

BLX---voice coil loudspeaker voice coil moves the electromotive force (claiming back electromotive force again) that produced (V) in magnetic field;

The vibration velocity of X---vibrational system (m/s).

Here should be specifically noted that this electromotive force oppositely occurs, can protect voice coil loudspeaker voice coil to bear high-power, big electric current and do not burnt.

2, the mechanics part of equivalent electric circuit

F＝XZ _M+F _A (N) (1-3)

Z in the formula _M---total mechanical impedance of vibrational system;

F _A---the sound reaction force of air during the vibrational system vibration, F _A=XZ _A(N), Z _A=R _MR+ X _MR, be total acoustic impedance (Ns/m).

$Z_M=R_{\mathrm{MS}}+R_{\mathrm{MR}}+j(\mathrm{\ω}{M}_{\mathrm{MS}}-\frac{1}{\mathrm{\ω}\·C_{\mathrm{MS}}})(N\·s/m)---(1-4)$

$R_{\mathrm{MS}}=\frac{{\mathrm{\ρ}}_0{C}^2{S}_D^2}{Q_{\mathrm{MS}}{\mathrm{\ω}}_S{V}_{\mathrm{AS}}}\left(\mathrm{mech\Ω}\right)$

(Q _MSValue has reflected the mechanical loss of speaker vibration system inside, V _ASThe equivalent volume of speaker vibration system compliance)

R in the formula _MR---effective radiation impedance, R _MR=ρ ₀c ₀S _DR ' _MR(Ns/m);

X _MR---radiation reactance, X _MR=ρ ₀c ₀S _DX ' _MR(Ns/m);

ρ ₀---atmospheric density, ρ ₀=1.21kg/m ³

C ₀---sound is propagation velocity (344m/s) in air;

S _D---the effective radiating area (m of awl basin ²);

R ' _MR---the dimensionless factor of radiation impedance live part;

X ' _MR---the dimensionless factor of radiation impedance reaction component.

According to above argumentation: can obtain following result

When ${\mathrm{\ω}}_{0}M=\frac{1}{{\mathrm{\ω}}_0.C}$ Shi Gongzhen, ${{\mathrm{\ω}}_0}^2=\frac{1}{M\·C},$ ${\mathrm{\ω}}_0=\frac{1}{\sqrt{M\·C}},$ Because

ω ₀＝2πf ₀

So $f_0=\frac{1}{2\mathrm{\π}\sqrt{M\·C}}---(2-1)$

In the formula, f ₀Resonance frequency for paper (awl) basin loudspeaker.M, C are exactly M _MSAnd C _MS

By formula (2-1) as can be known:

M (M in the formula _MS) be the quality of dynamic speaker oscillating component, when it increased, it is big that denominator becomes, f ₀Diminish.So when the quality of dynamic speaker oscillating component increased, the resonance frequency of loud speaker can reduce accordingly, the overall work frequency range can be offset to low frequency.Therefore, the quality that increases dynamic transducer (loud speaker) oscillating component is one and makes the overall work frequency range can be to the solution route of low frequency skew.

But, when reducing the low-frequency range cut-off frequency, because the increase of M causes the rapid decline of high band cut-off frequency again, simultaneously, integral device conversion efficiency variation.

The conversion efficiency variation can solve by improving power.

See formula (1-1) as can be known:

Increase power and improved I, then actuating force F increases, and can make it reach pre-provisioning request.

The decline of high band cut-off frequency then needs other searce way to solve;

The present invention is by with the energy transducer-piezoelectric disc of the piezoelectric speaker oscillating plate (substituting awl basin, tapered oscillating plate) as dynamic speaker.

In the low frequency frequency range, in magnetic field, pass to tone currents with voice coil loudspeaker voice coil after, the active force of generation promotes oscillating plate, the radiation low-frequency sound wave.Work in the PZT (piezoelectric transducer) mode in high-frequency band, the oscillating plate of piezoelectric produces vibration, radiation high frequency sound wave under effect of electric field.Then can solve the work problem of loudspeaker high frequency frequency range.

With reference to Fig. 3-Fig. 4, at the admittance analogy equivalent electric circuit of low frequency frequency range dynamic transducer (loud speaker).

Among the figure:

R _V----internal resistance of source

L _V----power supply inductance

m _V----voice coil loudspeaker voice coil quality

S _d-----centring disk

r _m----equivalent mechanical resistance

m _d----cone quality

S _s----ring mechanical stiffness

m _Ad----radiation quality

r _Ad----radiation resistance

m ₀＝m _v+m _d+2m _ad

S ₀＝S _d+S _s

r ₀＝r _m+2r _ad

We can obtain loud speaker low-frequency resonance frequency like this

$f_0=\frac{1}{2\mathrm{\π}}\sqrt{\frac{s_0}{m_0}}$

Therefore, when strengthening oscillating plate (awl basin) weight or increasing the ring compliance, all can reduce the low-frequency resonance frequency, improve low frequency characteristic.

With reference to Fig. 5, among the figure:

C ' _M----piezoelectric speaker mechanical compliance

The i----primary side is introduced electric current

C ' _E----piezoelectrics electric capacity

Wherein concern:

Feed current i at primary side, will capacitor C ' _ETwo ends cause a potential difference i/j ω C ' _E

At secondary end, the open circuit power that a certain specific direction of piezoelectrics produces is thus:

$f=\frac{i}{\mathrm{j\ω}{C}_E^{\′}}\mathrm{\τ}{C}_E^{\′}=\frac{\mathrm{i\τ}}{\mathrm{j\ω}}$

τ----coupling coefficient

During reverse transducing, as by the external world in the secondary end (a certain specific direction in piezoelectrics surface) of the transducer power that to apply a speed be v, then one of elementary generation by capacitor C ' _EElectric current--VC ' _Eτ is so can be regarded as to such an extent that open circuit voltage is;

$e=-v{C}_E^{\′}\mathrm{\τ}\frac{1}{\mathrm{j\ω}{C}_E^{\′}}=-\frac{\mathrm{\τv}}{\mathrm{j\ω}}$

With reference to Fig. 6-Fig. 7, a kind of pair of transducing mode combination coaxial full frequency speaker of the present invention, comprise magnetic structure 1, described magnetic structure 1 top is provided with voice coil loudspeaker voice coil 2, the output of described voice coil loudspeaker voice coil 2 is provided with oscillating plate, the disk 3 of described oscillating plate for adopting piezoelectric to make, described disk 3 is fixed on the magnetic structure by ring 4 and packing ring 5.

Be further used as preferred embodiment, described disk 3 adopts support to be fixed on the magnetic structure by ring 4.

Be further used as preferred embodiment, described piezoelectric is piezoelectric ceramic class material and/or fluorine-containing plastics piezoelectric.Described piezoelectric ceramic class material is barium titanate series, lead titanates system, niobate or lead zirconate titanate system.Described fluorine-containing plastics piezoelectric is macromolecular compound Kynoar PVDF material or other similar material.

With reference to Fig. 8-Fig. 9, be further used as preferred embodiment, described disk 3 and ring 4 are circle, ellipse, runway shape, square or accurate square.

Be further used as preferred embodiment, described voice coil loudspeaker voice coil 2 further is fixed on the position relative with magnetic structure 1 by centring disk 6.Described centring disk 6 adopts packing ring 5 or support to be fixed on the magnetic structure 1.

Be further used as preferred embodiment, described centring disk and ring are soft certain flexible material formation that has

With reference to Figure 10-Figure 11, be further used as preferred embodiment, described magnetic structure is external magnetic type structure or internal magnetization structure.

Among the present invention, disk that piezoelectric is made and attached ring thereof have substituted the taper oscillating plate (awl basin) on the original dynamic speaker.

Total quality of disk that piezoelectric is made and ring generally speaking, can be higher than taper oscillating plate (awl basin) on the dynamic speaker and total quality of attached ring thereof.

Reach the shared oscillating plate of high and low frequency with this.Simultaneously, reduce the resonance frequency of low frequency part, expanded low-frequency minimum.

At this moment, low-frequency range is dynamic speaker work, and disk that piezoelectric is made and ring integral body are done passive vibration, radiation low-frequency sound wave under the promotion of voice coil loudspeaker voice coil.High band be the disk made by piezoelectric under effect of electric field, produce the vibration radiation high frequency sound wave.

Like this, two transducing mode combination coaxial electro-acoustic transducer devices (full frequency speaker) can be operated in the frequency band of broad.Simultaneously, all acoustic radiation all derives from same oscillating plate (not only coaxial but also same sound source), has avoided acoustic interference.The present invention reaches the purpose that has reduced parts, reduced the loud speaker volume, reduces cost.

More than be that preferable enforcement of the present invention is specified, but the invention is not limited to described embodiment, those of ordinary skill in the art make all equivalent variations or replacement also can doing under the prerequisite of spirit of the present invention, the distortion that these are equal to or replace all is included in the application's claim institute restricted portion.

Claims (9)

1. two transducing mode combination coaxial full frequency speaker, comprise magnetic structure (1), described magnetic structure (1) top is provided with voice coil loudspeaker voice coil (2), the output of described voice coil loudspeaker voice coil (2) is provided with oscillating plate, it is characterized in that: the disk (3) of described oscillating plate for adopting piezoelectric to make, described disk (3) is fixed on the magnetic structure (1) by ring (4) and packing ring (5) or by support.

2. a kind of pair of transducing mode combination coaxial full frequency speaker according to claim 1 is characterized in that: described piezoelectric is piezoelectric ceramic class material and/or fluorine-containing plastics piezoelectric.

3. a kind of pair of transducing mode combination coaxial full frequency speaker according to claim 2 is characterized in that: described piezoelectric ceramic class material is barium titanate series, lead titanates system, niobate or lead zirconate titanate system.

4. a kind of pair of transducing mode combination coaxial full frequency speaker according to claim 2, it is characterized in that: described fluorine-containing plastics piezoelectric is macromolecular compound Kynoar PVDF material or other similar material.

5. a kind of pair of transducing mode combination coaxial full frequency speaker according to claim 1 is characterized in that: described disk (3) and ring (4) for circular, oval, runway shape is square or accurate square.

6. a kind of pair of transducing mode combination coaxial full frequency speaker according to claim 1 is characterized in that: described voice coil loudspeaker voice coil (2) further is fixed on and the relative position of magnetic structure (1) by centring disk (6).

7. a kind of pair of transducing mode combination coaxial full frequency speaker according to claim 6 is characterized in that: described centring disk (6) adopts packing ring (5) or support to be fixed on the magnetic structure (1).

8. according to claim 6 or 7 described a kind of pair of transducing mode combination coaxial full frequency speakers, it is characterized in that: described centring disk (6) is soft certain flexible material formation that has.

9. according to each described a kind of pair of transducing mode combination coaxial full frequency speaker of claim 1 to 7, it is characterized in that: described magnetic structure (1) is external magnetic type structure or internal magnetization structure.

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