close

Вход

Забыли?

вход по аккаунту

JPH0388500

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 JPH0388500
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker device suitable for constant current driving. SUMMARY OF THE INVENTION The present
invention relates to a speaker apparatus for driving an electrodynamic speaker with a constant
current amplifier, wherein a braking coil provided integrally with a vibration system of the
speaker is used as a braking magnet independent of the speaker magnetic circuit. By arranging in
the air gap of the circuit and terminating both ends of the braking coil with an arbitrary
impedance, the vibration system of the speaker can be appropriately electromagnetically braked
with a relatively simple configuration. 2. Description of the Related Art Heretofore, it has been
general to drive an electrodynamic (dynamic) speaker by a constant voltage system. In the case
of a normal direct emission type speaker, its electrical impedance is a bass resonance frequency f
as shown by a solid line in FIG. 5B. At the same time as the local maximum. Therefore, when such
a speaker is driven at a constant voltage, the drive current has a local minimum value at the bass
resonance frequency f0 and gradually decreases at a high frequency, as shown by a broken line
in FIG. Then, the output sound pressure frequency characteristic as shown in FIG. In the case of
constant voltage driving, since the output impedance of the signal source is zero, the damping
factor (damping factor) is infinite and substantially sufficient damping is applied to the vibration
system of the speaker. As is well known, in accordance with Fleming's left-hand rule, a force
proportional to the current flowing through the voice coil is applied to the vibration system of
the dynamic speaker. Therefore, if the above-mentioned speaker is driven by a constant current
signal source having an infinite output impedance, current distortion is well removed by the nonlinear reaction of the magnetic circuit, assuming that the drive should normally be driven by the
constant current method. At the same time, there is no noticeable increase in resistance due to
heat generation of the voice coil. But in this case the frequency f. There is a problem that an
increase in the output sound pressure response corresponding to an increase in the electrical
13-05-2019
1
impedance occurs in the vicinity of and in the high region, and the fidelity of the reproduced
sound is impaired. Furthermore, there is a problem that the damping factor becomes zero and
sufficient damping can not be applied to the vibration system. In order to solve such a problem,
conventionally, a speaker or system for constant current driving has been configured by adding
an appropriate braking resistance to a mechanical system or an acoustic system. However, in this
case, there has been a problem that the mechanical configuration of the speaker or the ball
arrangement system becomes complicated. In view of the above, it is an object of the present
invention to provide a speaker device capable of appropriately electromagnetically braking a
vibration system of a constant current driven speaker with a relatively simple configuration.
[Means for Solving the Problems] The present invention relates to a speaker apparatus for
driving an electrodynamic speaker (10) by a constant current amplifier (1), wherein a braking
coil (23) is integrated with a vibration system of the speaker. The braking magnetic circuit (25) is
provided independently of the speaker magnetic circuit (15), and the braking coil is disposed in
the magnetic gap of the braking magnetic circuit, and both ends of the braking coil are arbitrary.
The speaker device is configured to be terminated by the impedance (29) of [Operation]
According to the present invention, the vibration system of the constant current driven speaker is
appropriately electromagnetically braked with a relatively simple configuration. An embodiment
of a loudspeaker apparatus according to the present invention will be described below with
reference to FIGS. 1 and 2. FIG. The configuration of one embodiment of the present invention is
shown in FIGS. 1 and 2. FIG. (10) is a dynamic speaker in which a central portion of a coneshaped diaphragm (11) and a bobbin (12) are bonded, and a voice coil (13) is attached to one
end (12a) of the bobbin (12). It is wound. The peripheral edge of the diaphragm (11) is bonded to
one end of the frame (14). (15) is a magnetic circuit, which includes a magnet (16), a pole (17)
and a plate (18), is fixed to the other end of the frame (14), and the voice coil (13) is a pole
Coaxially disposed in the air gap between (17) and the plate (18). (20) is an electromagnetic
braking system, and a braking coil (23) is wound around the other end (12b) of the bobbin (12)
extended in the axial direction, and the coil (23) is wound around it. A braking magnetic circuit
(25) including a magnet (26) is provided and a coil (23) is disposed in the air gap between the
pole (27) and the plate (28). (24) is a supporting member. As shown in FIG. 2, the voice coil (13)
is connected to a drive amplifier shown as a constant current source (1) and a braking coil (23) is
connected to a half fixed resistor (29). Instead of the resistor, an appropriate impedance having
frequency characteristics may be connected. When the drive current i + o is supplied to the voice
coil (13) of the speaker (10), the diaphragm (11) and the bobbin (12). The voice coil (13) vibrates
in unison. Along with this, the coil (23) of the other end (12b) of the bobbin (12) also vibrates in
the magnetic circuit (25). Then, an electromotive force e is generated in the coil (23) in
proportion to the length and the vibration velocity and the magnetic flux density of the magnetic
circuit (25) according to Fleming's right-hand rule, and the electromotive force e and the
resistance are generated. A current of 12 ° flows, which is determined by the resistance value
R29 of the container (29).
13-05-2019
2
This current Lo generates a force in the opposite direction to the vibration direction of the
bobbin (12) from the interaction with the magnetic circuit (25). This force is transmitted to the
diaphragm (11) via the bobbin (12), and the diaphragm (11) is appropriately braked. Since the
braking current Lo is also a detection current corresponding to the movement of the vibration
system of the speaker (10), the movement of the vibration system is controlled by feedbacking
this to the signal fi (1) to perform motional feedback. And the required sound reproduction
characteristics. Next, with reference to FIG. 3 and FIG. 4, another embodiment of the speaker
apparatus according to the present invention will be described. The construction of another
embodiment of the present invention is shown in FIGS. 3 and 4. FIG. In these figures, parts
corresponding to those in FIG. 1 and FIG. 2 are given the same reference numerals. In FIG. 3, a
fixed coil (22) is provided facing the braking coil (23) in the braking system (201). The coil (22)
may be wound around the outer periphery of the ball (27) of the magnetic circuit (25) as shown,
or may be disposed on the inner peripheral surface of the play 1- (28). Then, in this embodiment,
as shown in FIG. 4, the braking coil (23) is shorted. The rest of the configuration is the same as
the embodiment shown in FIG. 1 and FIG. In this embodiment, a relatively large braking current
1233 is obtained by dividing the electromotive force e generated in the coil (23) by the
resistance of the coil (23) (if'frz3), and the diaphragm (11) is sufficiently braked. Ru. In addition,
motional feedback can be easily performed using the electromotive force induced
electromagnetically in the fixed coil (22). As described above, according to the present invention,
the braking coil integrally provided with the vibration system of the electrodynamic speaker is in
the air gap of the braking magnetic circuit independent of the magnetic circuit of the speaker.
Thus, a speaker device capable of electromagnetically braking the system appropriately at both
ends of the braking coil can be obtained.
[0002]
Brief description of the drawings
[0003]
1 and 2 are a cross-sectional view and a block diagram showing the configuration of an essential
part of an embodiment of a loudspeaker apparatus according to the present invention, and FIGS.
3 and 4 are an essential part of another embodiment of the present invention. FIG. 5 is a crosssectional view and a block diagram showing the structure of FIG. 5, and FIG. 5 is a characteristic
curve diagram for explaining the present invention.
13-05-2019
3
(1) is a constant current source, (10) is a speaker, (13) is a voice coil, (15), (25) is a magnetic
circuit, (20), (2OA) is an electromagnetic braking system, (22) is a pickup coil , (23) is a control
coil, and (29) is a braking resistor. Agent Hidetoshi Matsushima
13-05-2019
4
1/--страниц
Пожаловаться на содержимое документа