1. Field of the Invention
This invention relates to structure of a speaker.
The present application claims priority from Japanese Application No. 2004-40372, the disclosure of which is incorporated herein by reference.
2. Description of the Related Art
Typically, various network elements, such as choke coils, capacitors and resistances, are connected to a speaker for control of audio signals inputted to the speaker.
In
In the case of a speaker apparatus having a speaker P connected to such network elements which have been housed in the control box 1 provided independently of the speaker P, the control box 1 is connected to some part of the wiring to the speaker P. For example, for a vehicle-mounted speaker, the wiring must be carried out after providing for a space required for installing the control box 1 in a door of the vehicle, a console or the like. This process makes the installation hard. Further, because the speaker P and the network elements are at a distance from each other, the loss of power causes speaker performance degradation.
For this reason, a speaker having network elements attached to a speaker body as illustrated in
Such a speaker is disclosed in Japanese Patent application Laid-open No. 2002-142284, for example.
The conventional speaker as illustrated in
However, in such a speaker having the network element N attached to the frame Ph of the speaker P, the proximity of the network element N and voice coils Pc of the speaker allows electromagnetic induction generated around the choke coil (i.e. the network element N) to give rise to an induced current in the voice coils Pc, leading to problems of degradation of performance of the speaker P and the like.
An object of the present invention is to solve the problems associated with the conventional speakers as described above.
To attain this object, the present invention provides a speaker characterized in that a magnetic circuit driving a diaphragm is provided in a sound emission area close to the diaphragm, and a network element is installed on the opposite side of a frame member, supporting the diaphragm, from the sound emission area of the diaphragm.
In the best mode for carrying out the present invention, a speaker is provided with a tubular-shaped magnetic-circuit supporter that is formed integrally with a frame member forming an outer frame of a speaker and supporting a diaphragm and projects from an inside central portion of the frame member so as to pass through a central portion of the diaphragm from the rear thereof to the sound emission area. A magnetic circuit is installed and supported at a leading end of the magnetic-circuit supporter. Further, a network element of the speaker is installed on a rear face of the frame member that is located at a distance from the position of installation of the magnetic circuit and at a rear end of the magnetic-circuit supporter situated behind the diaphragm.
The speaker according to the best mode outputs sound from the diaphragm upon reception of audio signals via the network element installed on the rear face of the frame member.
For the reception of audio signals, in the speaker, the magnetic circuit is located in the sound emission area close to the diaphragm, whereas the network element is located on the rear face of the frame member. Hence, because the distance between the magnetic circuit and the network element is increased as compared with that in the conventional speaker, the influence of the network element on the magnetic circuit is smaller. In consequence, there is no danger that installing the network element will cause degradation of speaker performance.
Further, the speaker is capable of having the network element installed integrally with the speaker body. For this reason, for example, when the speaker is used as a vehicle-mounted multi-way speaker, significant improvement in ease of installation would be achieved.
Still further, the magnetic circuit of the speaker is located in the sound emission area close to the diaphragm. In other words, the magnetic circuit is able to be situated in the cone shape of the diaphragm, thereby making it possible to reduce the thickness of the speaker.
These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.
First Embodiment
In
A ring-shaped first plate 11 is secured concentrically on the leading end face of the magnetic-circuit supporter 10B (the left end face in
In turn, a second plate 13 of the same outer diameter as that of the first plate 11 is secured concentrically on the front face of the magnet 12 (the left face in
A tubular-shaped support frame 14 is secured concentrically on the front face of the second plate 13, and is larger in outer diameter than the first plate 11, the magnet 12 and the second plate 13.
The support frame 14 has a groove 14A formed in an annular shape concentric with the body and in the rear face of the support frame 14. The groove 14A has a smaller inner diameter and a larger outer diameter than the outer diameter of the first plate 11 and the second plate 13.
A depth of the groove 14A (width in the direction of the center line of the support frame 14) is set greater than the excursion (or the amount of travel) of a diaphragm which will be described later.
A ring-shaped yoke 15 is fixed concentrically on the rear face of the support frame 14 (the right face in
In this manner, a magnetic circuit C is formed by the first plate 11, magnet 12, second plate 13, support frame 14, and the yoke 15.
Further, a voice coil bobbin 16 vibrating in the direction of the center line is fitted concentrically over the supporter 10B of the frame 10, the first plate 11, the magnet 12 and the second plate 13. A front portion of the voice coil bobbin 16 (the left portion in
A first voice coil 16A is wound on a portion of the voice coil bobbin 16 facing the outer peripheral face of the first plate 11 inside the magnetic gap. A second voice coil 16B is wound on a portion of the voice coil bobbin 16 facing the outer peripheral face of the second plate 13 inside the magnetic gap.
A cone-shaped diaphragm 17 is secured at its inner circle end to the outer periphery of the rear end of the voice coil bobbin 16. The outer circle end of the diaphragm 17 is supported through an edge 18 by the periphery of the front end of the frame body 10A.
A damper 19 is interposed between the frame body 10A and the portion of the rear end of the voice coil bobbin 16 which is coupled to the diaphragm 17. The damper 19 supports the voice coil bobbin 16 and the diaphragm 17 and allows them to vibrate in the direction of the center line.
A network element installation member 20 is provided in a central portion of the rear face of the frame 10 (the rear end face of the magnetic-circuit supporter 10B) . A network element (choke coil in the example shown in
For audio output from the speaker P1, an audio signal is inputted to the speaker through the network element N supported by the network element installation member 20, and therefore electric current passes through the first voice coil 16A and the second voice coil 16B. Thereupon, interaction between the electric current and a magnetic field produced by the magnet 12 causes vibration of the voice coil bobbin 16 in the direction of the center line (in the right-left direction in
In the speaker P1, the magnetic circuit C is located in the sound emission area close to the diaphragm 17 (i.e. on the left hand in
Further, because the network element N is installed integrally with the speaker body, when the speaker P1 is used as, e.g., a vehicle-mounted multi-way speaker, it is possible to significantly improve ease of installation.
Still further, the magnetic circuit C of the speaker P1 is located in the sound emission area of the cone-shaped diaphragm 17. In other words, the magnetic circuit C is situated inside the cone shape of the diaphragm 17, thereby making it possible to reduce the thickness of the speaker.
Second Embodiment
The choke coil, i.e. the network element N, of the speaker P1 of the first embodiment is wound about the center line of the network element installation member 20 which is coaxial with the frame 10. However, in a speaker P2 in the second embodiment shown in
The remaining structure of the speaker P2 is the same as that of the speaker P1 in the first embodiment, and therefore the same components are designated by the same reference numerals as those in
As in the case of the speaker P1 in the first embodiment, in the speaker P2, the magnetic circuit C is located in front of the diaphragm 17, whereas the network element N is located behind the frame body 10A. Hence, the distance between the magnetic circuit C and the network element N is increased as compared with that in the conventional speaker as shown in
Further, because the network element N is installed integrally with the speaker body, when the speaker P2 is used as a vehicle-mounted multi-way speaker, for example, significant improvement in ease of installation is achieved.
Still further, the magnetic circuit C of the speaker P2 is located in the sound emission area of the cone-shaped diaphragm 17. In other words, the magnetic circuit C is situated inside the cone shape of the diaphragm 17, thereby making it possible to reduce the thickness of the speaker.
The terms and description used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that numerous variations are possible within the spirit and scope of the invention as defined in the following claims.
Number | Date | Country | Kind |
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2004-40372 | Feb 2004 | JP | national |