close

Вход

Забыли?

вход по аккаунту

JPH11298992

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH11298992
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker device used for various audio devices and video devices.
[0002]
2. Description of the Related Art A typical speaker device of the prior art is configured as shown
in FIG. This is called a dynamic type speaker, and the magnetic circuit of this speaker device
comprises a donut shaped magnet 1, first and second magnetic yokes 2 and 3 made of a
magnetic material such as iron, and an air gap. (Gap) 4 is comprised. The first magnetic yoke 2 is
composed of a columnar pole piece 2a and a disk-shaped flange portion 2b orthogonal to the
center pole portion 2a. The second magnetic yoke 3 is called a plate, and has a donut shape
whose inner diameter is larger than the outer diameter of the pole piece 2 a by the space 4.
[0003]
Then, with the pole piece 2 a inserted in the inner peripheral hollow portion of the magnet 1 and
the inner peripheral hollow portion of the plate 3, the magnet 1 is formed by the front surface of
the flange portion 2 b of the first magnetic yoke 2 and the plate 3. Is attached in place. The
contact portion between the front surface of the flange portion 2b and the surface of the plate 3
and the magnet 1 is bonded.
13-05-2019
1
[0004]
Then, the voice coil 6 wound around the non-conductive voice coil bobbin 5 is disposed so as to
be located in the air gap 4 between the plate 3 and the pole piece 2 a. Further, an acoustic
diaphragm 7, for example, a cone paper is attached to and attached to the voice coil bobbin 5.
The acoustic diaphragm 7 is attached and fixed to the speaker frame 8 at its edge portion. A
signal input line (lead line) 9 is derived from the voice coil 6.
[0005]
In the speaker device of FIG. 4, when the current I by the acoustic signal flows through the voice
coil 6, the interaction with the magnetic flux B of the magnetic gap 4 generates a driving force F
that causes the acoustic diaphragm 7 to vibrate. The driving force F can be expressed as F = B ×
I × D (Equation 1). Here, D is the length of the voice coil 6 in the magnetic field.
[0006]
Since this dynamic type speaker device has a signal input line in the vibration system, it has a
problem in terms of the vibration balance of the acoustic vibration system. Further, since the
voice coil 6 generates heat due to the flow of the signal current, it is necessary to consider the
breakage of the bobbin due to the heat generation of the voice coil 6, and there is a problem that
the signal current which can be flowed is limited.
[0007]
On the other hand, an electromagnetic induction type speaker device is known. This is because
when a primary coil for excitation is wound around a pole piece, and a secondary coil consisting
of a conductive one turn ring is provided in the air gap of the magnetic circuit, and a signal
current flows through the primary coil. An induced current is induced in the secondary coil, and
the induced current cuts a magnetic flux in the air gap to generate a driving force for driving an
acoustic diaphragm joined to the secondary coil.
13-05-2019
2
[0008]
In this electromagnetic induction type speaker device, since the exciting primary coil to which
the signal current is supplied is wound around the pole piece having good thermal conductivity,
it is easy to dissipate the heat of the primary coil, and the comparison is made. There is an
advantage that a very large signal current can flow to the primary coil. Further, since there is no
signal input line in the vibration system, there is a feature that the vibration balance of the
acoustic vibration system is also good.
[0009]
SUMMARY OF THE INVENTION Although the electromagnetic induction type speaker device has
the features as described above, the magnitude of the induced current flowing in the secondary
coil consisting of a one-turn conductive ring is equal to that of the primary coil and the
secondary Depending on the constant of the coil, depending on the selection of the constant,
even if the signal current flowing through the primary voice coil is large, a current of a desired
magnitude does not flow as an induced current, which may result in inefficiency.
[0010]
An object of the present invention is to make it possible to efficiently induce an induced current
in a secondary coil in an electromagnetic induction type speaker device in view of the above
points.
[0011]
SUMMARY OF THE INVENTION In order to solve the above problems, a speaker device according
to the present invention is provided in the vicinity of an air gap in a magnetic circuit, and a
primary coil supplied with a current according to an input audio signal; The secondary coil
disposed in the air gap, in which a current is induced according to the current flowing in the
primary coil, and the interaction between the current induced in the secondary coil and the
magnetic flux in the air gap And a diaphragm configured to vibrate by vibrating the next coil,
wherein the DC resistance value of the primary coil is R1, the inductance is L1, the DC resistance
value of the secondary coil is R2, and the inductance is L2, the inductance The respective
constants R1, R2, L1, and L2 are selected such that the ratio L1 / L2 of the two is equal to the
ratio R1 / R2 of the direct current resistance.
[0012]
13-05-2019
3
According to the invention of claim 1, by selecting the constants of the primary coil and the
secondary coil as described above, the induced current flowing through the secondary coil is
maximized, and an efficient electromagnetic induction speaker Can be realized.
[0013]
DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the speaker
apparatus according to the present invention will be described below with reference to the
drawings.
In the present invention, an electromagnetic induction system is used as a drive system of the
acoustic diaphragm.
[0014]
FIG. 1 shows the structure of an electromagnetic induction type speaker device according to this
embodiment.
Also in the speaker device of this example, the magnetic circuit is configured in the same manner
as the speaker device of the example of FIG. 4 and includes the first yoke 12 including the
cylindrical pole piece 12a and the disk-like flange portion 12b; 2 and a doughnut-shaped plate
13 constituting a yoke, a doughnut-shaped magnet 11 disposed between the flange portion 12b
of the first yoke 12 and the plate 13, a gap between the plate 13 and the pole piece 12a A
magnetic circuit is constituted by 14.
[0015]
Then, a drive coil as an excitation primary coil is disposed on either or both of the outer
peripheral surface portion of the pole piece 12 a and the inner peripheral surface portion of the
plate 13 facing each other across the air gap 14.
In this embodiment, an excitation primary coil 15 is disposed on the outer peripheral surface of
13-05-2019
4
the pole piece 12a.
In order to dispose the primary coil 15, a small diameter portion having a length corresponding
to the winding width of the primary coil 15 may be provided in the vicinity of the top of the pole
piece 12a.
[0016]
The signal input wire (lead wire) 16 derived from the primary coil 15 is extended to the back side
of the flange portion 12 b through the through hole 17 provided in the flange portion 12 b of the
first magnetic yoke 12.
[0017]
And in this embodiment, the secondary coil 18 which consists of a short coil electromagnetically
coupled to the primary coil 15 is inserted into the air gap 14.
In this example, the secondary coil 18 is configured as a one-turn short coil by a cylindrical ring
of nonmagnetic and conductive material such as aluminum. Then, the conductive one turn ring
made of aluminum that constitutes the secondary coil 18 is adhesively fixed to the bobbin 19.
The bobbin 19 is made of a nonmagnetic and nonconductive material such as cardboard.
[0018]
The width of the secondary coil 18 (corresponding to the height of one turn ring) is the minimum
necessary length that is longer than the length in the vibration direction of the air gap 14 by the
amplitude of the vibration of the secondary coil 18 The length of
[0019]
Then, the acoustic diaphragm 20, for example, cone paper is attached to the bobbin 19.
The acoustic diaphragm 20 is attached to the speaker frame 21 via a flexible edge (not shown).
13-05-2019
5
[0020]
In the speaker apparatus of the electromagnetic induction type configured as described above,
when a signal current is caused to flow through the excitation primary coil 15, an induced
current is generated in one turn of the secondary coil 18 disposed opposite to the primary coil
15. Flows. The driving force F for driving the secondary coil 18 in the height direction of the ring
is generated from the induced current I flowing through the secondary coil 18 and the magnetic
flux density B in the air gap 14, whereby the acoustic diaphragm 20 is It vibrates according to
the signal current.
[0021]
In this case, assuming that the length of one turn ring (the length of the circumference of the
ring) as the secondary coil 18 is L, the driving force F is F = B × I × L (Equation 2)
[0022]
In this embodiment, assuming that the DC resistance of the primary coil 15 is R1, the inductance
is L1, the DC resistance of the secondary 18 is R2, and the inductance is L2, L1 / L2 = R1 / R2 ...
(Equation 3) Each constant is selected.
[0023]
Further, assuming that the coupling coefficient of the primary coil 15 and the secondary coil 18
is k, and the coupling coefficient k is equal to 1, the above (Equation 3) is N2 = R1 / R2L1 / L2 =
N2 (Equation 4) )It can be expressed as.
[0024]
By selecting the respective constants L1, L2, R1 and R2 as described above, the induced current
of the secondary coil 18 serving as the driving force of the acoustic diaphragm is maximized, so
that an efficient electromagnetic induction speaker device can be realized, The square of the
number of turns of the primary coil is set to be equal to the ratio of the direct current resistance
value R1 of the primary coil to the direct current resistance value R2 of the secondary coil.
This will be further described below.
13-05-2019
6
[0025]
The electrical equivalent circuit of the electromagnetic induction unit of the above-described
electromagnetic induction speaker device can be expressed as shown in FIG.
In FIG. 2, as described above, R1 and L1 are the DC resistance value and inductance of the
primary coil 15 for excitation, respectively, and R2 and L2 are the DC resistance value and
inductance of the secondary coil 18 respectively. is there.
And M is a mutual induction inductance and Zin is an input impedance of the speaker device.
[0026]
Now, when the speaker device of the electromagnetic induction system is driven at constant
voltage, the frequency characteristics of the induced current flowing in one turn ring as the
secondary coil 18 acting as a driving force are as follows.
[0027]
That is, assuming that the drive voltage is V1 and the induction current of secondary coil 18 is
I2, the frequency characteristic of induction current I2 with respect to drive voltage V1 is I2 / V1
= ω · k (L1 × L2) 1/2 / Y1 / 2Y = .Omega.2 * (L1.times.R2 + L2.times.R1) 2 + {-R1.times.R2 +
.omega.2 * L1.times.L2 * (1-k2)} 2 (5)
[0028]
From (Equation 5), the maximum value I2 / V1 (max) of the induction current I2 is I2 / V1 (max)
= k × (L1 × L2) 1/2 / (L1 × R2 + L2 × R1) (6) )It can be expressed as.
[0029]
If the above (formula 4) is satisfied, the right side of the above (formula 6) becomes maximum.
13-05-2019
7
That is, the induced current I2 is maximum.
[0030]
Thus, as shown in (Equation 3), the ratio of the inductance L1 of the exciting primary coil 15 to
the inductance L2 of the secondary one-turn conductive ring 18 is the ratio of the DC resistances
of the respective coils 15, 18 It can be seen that the value of the induced current I2 of the
secondary coil 18 is at the maximum value when
[0031]
When the coupling coefficient k is equal to 1, the square of the number of turns N of the exciting
primary coil 15 is equal to the DC resistance value R1 of the exciting primary coil 15 and the
secondary as shown in (Equation 4) It can be seen that the induced current I2 is at a maximum
when it is equal to the ratio of the coil 18 to the DC resistance R2.
[0032]
Embodiment A specific embodiment of the excitation primary coil 15 and the secondary coil 18
of the speaker apparatus having the above-described configuration will be described.
[0033]
In this example, the characteristics of one turn ring as the exciting primary coil 15 and the
secondary coil 18 were as follows, and the frequency characteristic of the driving force was
calculated from the magnitude of the induced current.
The calculation was performed using the inductance L2 of the secondary coil 18 consisting of a
one-turn conductive ring as a parameter.
The coupling coefficient k was set to k = 0.9.
The drive voltage V1 was 4 volts, the magnetic flux density in the magnetic circuit was 1.5 Tesla,
and the length of the one-turn conductive ring was 0.042 m.
13-05-2019
8
[0034]
The excitation primary coil 15 has a DC resistance (R1) of 3.22 Ω and an inductance (L1) of 34.5
μH.
[0035]
The secondary coil 18 (one turn conductive ring) has a DC resistance (R2): 0.00207 Ω, an
inductance (L2): a parameter
[0036]
The calculation results are shown in FIG.
Thereby, it was confirmed that the driving force is maximized when the inductance ratio L1 / L2
satisfies (Expression 3).
Further, when the coupling coefficient k is 1, the number of turns N is set to 39 from (Expression
4).
[0037]
In this embodiment, the inductance L2 of the secondary coil 18 of the one-turn conductive ring is
changed as a parameter to determine the constant. However, the inductance L2 of the secondary
coil 18 is determined, and the primary Of course, the inductance L1 of the coil 15 may be
changed as a parameter to be determined so as to satisfy the equation (3).
[0038]
As described above, according to the present invention, the size of the induced current can be
maximized by optimizing each constant of the electromagnetic induction unit, and the
electromagnetic induction speaker apparatus with high efficiency can be obtained. Can be
realized.
13-05-2019
9
1/--страниц
Пожаловаться на содержимое документа