JP3478927B2 - Speaker - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a speaker.

[0002]

2. Description of the Related Art Speakers attached to monitors are
In many cases, the arrangement space is not sufficient, and in order to secure the necessary sound pressure level, an elliptical shape was used to try to secure a larger diaphragm area in a restricted space. The outline is shown in FIGS. 9 (a) and 9 (b). Further, when trying to obtain a lower sound with a speaker, there are bass reflex, a passive radiator system, and the like, but the above-mentioned speaker has a limited cabinet volume, and a sufficient effect cannot be obtained. FIG. 10 shows the frequency characteristic in such a case. The curve indicated by a in FIG. 10 is a characteristic when the cabinet volume is optimum, c is a characteristic when the cabinet volume is small,
b shows the characteristics in the case of the closed type having the same volume. That is, if the cabinet volume cannot be increased,
As indicated by c of 0, as the low frequency reproduction limit rises, a crest due to resonance occurs in the low frequency range.

In a generally known speaker, for example, as shown in FIG. 9A, a magnet 8 creates a magnetic field in a magnetic gap composed of a magnetic pole 7 and a center pole 4, and the magnetic field Voice coil 6 wound on bobbin 2
Is arranged, and the bobbin 2 is driven by the electromagnetic action of the current and magnetic field applied to the voice coil 6 to vibrate the diaphragm 1. The diaphragm 1 is attached to the frame 10 by the edge 9 and the damper 3. A protective cap 11 for dust-proofing the magnetic poles is arranged at the center of the diaphragm 1.

[0004]

In the bass enhancement method using resonance such as bass reflex, it becomes difficult to lower the resonance frequency due to its shape as the cabinet volume becomes smaller, and the resonance frequency is lowered unreasonably. Therefore, it becomes difficult to increase the resonance sharpness, and it is difficult to sufficiently exert the effect.

Generally, in a speaker having a non-rotationally symmetric diaphragm having a major axis and a minor axis, turbulence occurs in the vicinity of the middle region due to the sound pressure characteristic as shown in FIG. If the diaphragm shape is elliptical or elliptical, the rigidity of the diaphragm will be weaker than that of a circular shape.
The reason is that the vibration near the center of the diaphragm in the major axis direction becomes larger than that at other places. Moreover, the vibration plate is twisted at the time of vibration, and when the twist is generated, a problem of contact between the magnetic circuit and the voice coil occurs. Further, the largest twist occurs near the center of the major axis. This becomes a factor that deteriorates the frequency characteristics of the speaker.

Further, when the diaphragm area is increased in order to increase the reproduced sound pressure level of the speaker, the volume of the cabinet is equivalently reduced, and it becomes more difficult to reproduce the low sound.

Further, since the voice coil diameter cannot be made sufficiently large, it is difficult to obtain a large driving force and it is difficult to improve the bass reproduction capability. There was also a method of using an oval voice coil to improve this, but since the resonance is likely to occur, ribs and members for reinforcement to improve this were attached, which made the structure complicated.

The present invention has been made in view of the above points, and an object thereof is to provide a speaker having excellent frequency characteristics.

[0009]

A speaker according to claim 1 has a diaphragm and a voice coil arranged in a part of the diaphragm, and an outer peripheral portion of the voice coil of the diaphragm is an inner peripheral portion of the voice coil. It is possible to vibrate with different vibrations, and the lowest resonance frequency of the outer peripheral portion of the voice coil is lower than the lowest resonance frequency of the speaker. The speaker according to claim 2, wherein the speaker has a non-rotationally symmetric diaphragm whose planar shape as viewed from the vibration direction has a major axis and a minor axis, the speaker has a voice coil disposed in a part of the diaphragm, and vibrates. The outer peripheral portion of the voice coil of the plate can vibrate with a different vibration from the inner peripheral portion of the voice coil, and the lowest resonance frequency of the outer peripheral portion of the voice coil is lower than the lowest resonance frequency of the speaker. The speaker according to claim 3, wherein the speaker has a non-rotationally symmetric diaphragm whose planar shape viewed from the vibration direction has a major axis and a minor axis, and the weight near the center of the diaphragm is greater than the weight of the outer peripheral portion of the diaphragm. Characterized by being large. The speaker according to claim 4 is the speaker according to claim 2, characterized in that the weight near the center of the diaphragm is non-rotationally symmetric with respect to the major axis and the minor axis. The speaker according to claim 5 is the speaker according to claim 2, characterized in that the thickness distribution of the diaphragm is increased only near the center. The speaker according to claim 6, wherein the speaker has a non-rotationally symmetric diaphragm whose planar shape as viewed from the vibration direction has a major axis and a minor axis, and has a magnetic circuit for supplying magnetic flux to a voice coil, and the magnetic circuit. In (1), the gap width in the minor axis direction is larger than the gap width in the major axis direction. Claim 7
In a speaker having a non-rotationally symmetric diaphragm whose planar shape viewed from the vibration direction has a major axis and a minor axis, the speaker according to the paragraph (1) has a magnetic circuit for supplying magnetic flux to the voice coil, and the voice coil or the magnetic circuit. Is provided with a sliding portion, and the sliding portion is slid with a magnetic circuit or a voice coil.

[0010]

In the speaker according to the first aspect of the present invention, the outer periphery of the voice coil of the diaphragm can be vibrated with a different vibration from the inner periphery of the voice coil, and the lowest resonance frequency of the outer periphery of the voice coil is lower than the lowest resonance frequency of the speaker. As a result, the equivalent vibration amplitude can be increased below the lowest resonance frequency of the speaker,
You can increase the sound pressure level and expand the bass reproduction frequency. In the speaker according to claim 2, since the outer periphery of the voice coil of the diaphragm can be vibrated with a different vibration from the inner periphery of the voice coil, and the lowest resonance frequency of the outer periphery of the voice coil is lower than the lowest resonance frequency of the speaker. The equivalent vibration amplitude can be increased below the lowest resonance frequency of the speaker, the sound pressure level can be increased, and the bass reproduction frequency can be expanded. In the speaker according to the third aspect, since the weight near the center of the diaphragm is larger than the weight of the outer peripheral portion of the diaphragm, the mid-range characteristic can be improved. In the speaker according to the fourth aspect, the weight in the vicinity of the center of the diaphragm is configured to be non-rotationally symmetrical with respect to the major axis and the minor axis, so that the midrange characteristic can be improved. In the speaker according to the fifth aspect, since the thickness distribution of the diaphragm is thick only in the vicinity of the center, the middle range characteristic can be improved. In the loudspeaker according to the sixth aspect, the efficiency of the magnetic circuit can be improved by increasing the gap width in the minor axis direction in the magnetic circuit with respect to the gap width in the major axis direction. In the loudspeaker according to claim 7, the voice coil or the magnetic circuit is provided with the sliding portion, and the sliding portion is configured to slide with the magnetic circuit or the voice coil. The turbidity phenomenon can be suppressed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION According to the speaker of the present invention, FIG.
As shown in FIG. 1, the diaphragm 101 is a non-rotationally symmetric type having major and minor diameters of a substantially oval shape. As shown in the side view of FIG. It is divided into diaphragm 101b on the outer peripheral portion. Here, rotational symmetry means that the cross-sectional shape including a specific axis has the same shape at any angle. Further, the specific axis refers to the axis in the center of the diaphragm. The lowest vibration frequency (f _0b ) of the outer peripheral diaphragm 101b is set so that different vibrations can be set between the inner peripheral diaphragm 101a and the outer peripheral diaphragm 101b.
Is the lowest resonance frequency f of the entire speaker including the cabinet 12 in which the diaphragm 101a and the diaphragm 101b are combined.
By setting it lower than _0T, it is possible to widen the low-frequency characteristic of the speaker. Since the lowest resonance frequency f ₀ is determined by the stiffness and the diaphragm weight, the lowest resonance frequency f ₀ may be adjusted by adjusting both of them. The magnet 8, the center pole 4, the voice coil 6, and the edge 9 are the same as in the conventional case described above, and the yoke 34 forms a magnetic circuit with the magnet 8 and the center pole 4. The tinsel wire 35 guides an electric signal input from the input terminal 36 to the voice coil 6.

When the mass of the diaphragm is m and the stiffness is S, the lowest resonance frequency is inversely proportional to the square root of m / S. Therefore, in order to lower the minimum resonance frequency f _0b ,
This can be achieved by increasing the mass, that is, the weight of the outer peripheral diaphragm 101b, or by reducing the stiffness of the outer peripheral diaphragm 101b.

As for the operation of the diaphragm, in the low frequency range, the outer peripheral portion vibrates more than in the inner peripheral portion, as compared with the inner peripheral portion, as shown in FIG. However, the sound pressure in the low range can be increased. The solid line in FIG. 3 indicates the neutral position of the diaphragm, and the broken line indicates the vibration position. The frequency characteristic in this case is as shown in FIG. 2, where b is the frequency characteristic of the diaphragm on the inner peripheral portion, c is the frequency characteristic of the diaphragm on the outer peripheral portion, and a is the frequency characteristic obtained by combining b and c. In FIG.
Vibration plates 101a and 101b, voice coil 6, edge 9
Has the same configuration as in FIG.

FIG. 4 is a diagram showing the configuration of the diaphragm together with other configuration examples. FIG. 4B shows a basic configuration, and when the diaphragm of the outer peripheral portion has too high stiffness due to the setting of the minimum resonance frequency f ₀ of the diaphragm of the outer peripheral portion, FIG.
It is also possible to adjust the outer peripheral diaphragm closer to the inner diaphragm as the corrugation shape so as to reduce the stiffness as shown in (c). Further, the shape of the diaphragm on the outer peripheral portion may be flat as shown in FIG. 4, the diaphragms 101a and 101b, the voice coil 6, and the edge 9 have the same configuration as in FIG. 1, but the joint portion 5 is the joint portion between the diaphragms 101a and 101b, and the joint portion 5a.
Shows the case where the corrugated joint 5a is arranged at the joint between the diaphragms 101a and 101b.

Next, a description will be given of a configuration in which the weight (per unit area) near the center of the diaphragm at the inner peripheral portion is set to be heavier than the weight at other locations. By doing so, the difference in vibration width between the central portion and the outer peripheral portion in the major axis direction of the diaphragm is reduced, and the characteristic of the diaphragm having a uniform weight per unit area as shown in FIG. 8A is disturbed. However, as shown by b, the disturbance in the middle range can be suppressed.

Further, as shown in FIG.
Is provided on the vibrating plate 101a to distribute the weight by a long diameter,
By making it asymmetric with respect to the minor axis, the turbulence in the mid range can be dispersed, and the turbulence in the mid range can be suppressed more effectively.
Further, it is conceivable to attach a load to the diaphragm to change the weight, but this will increase the number of manufacturing processes such as attaching the load and managing the position during attachment.

Therefore, the weight distribution is changed by changing the thickness of the diaphragm. According to this structure, the weight distribution can be changed without increasing the manufacturing process. It should be noted that the diaphragm can be integrally molded by using a resin such as polypropylene as an example of the material.

Next, since the manufacturing error in the major axis direction is larger than that in the minor axis direction of the diaphragm, in the speaker having the non-rotationally symmetric diaphragm having the major axis and the minor axis, the gap width of the magnetic circuit is constant over the entire circumference. Then, the possibility of contact between the voice coil and the magnetic circuit increases in the major axis direction between the center pole 4 and the yoke 34 shown in FIG. 6B. Here, it is conceivable that the entire circumference is elliptical with a sufficient gap width also in the major axis direction, but since the gap width becomes unnecessarily large in the minor axis direction shown in FIG. 6A, the magnetic flux density at which the voice coil operates. Lowers the efficiency. Therefore, the gap width in the major axis direction is set larger than the gap width in the minor axis direction.

By adopting such a configuration, even a speaker having a non-rotationally symmetric diaphragm having a major axis and a minor axis,
It is possible to make an efficient speaker.

Next, FIG. 7 shows a structure in which the sliding member 33 is provided near the central portion of the major axis of the magnetic circuit. With such a configuration, the voice coil can be slid in the magnetic circuit portion to suppress the twist of the diaphragm during vibration. As shown in FIG. 7, the twist can be suppressed most efficiently by sliding near the center of the major axis. Conversely, a sliding member may be provided on the voice coil so that the voice coil slides on the magnetic circuit. 7, the center pole 4, the voice coil 6 magnet 8, and the yoke 34 are the same as those in FIG. 1 described above.

[0021]

As described above, according to the speaker of the present invention, a speaker having a non-rotationally symmetric diaphragm whose planar shape as viewed from the vibration direction has a major axis and a minor axis,
Since the outer periphery of the voice coil of the diaphragm can be vibrated with a different vibration from the inner periphery of the voice coil, and the lowest resonance frequency of the voice coil outer periphery is configured to be lower than the lowest resonance frequency of the beaker, it is less affected by the cabinet volume, The low frequency characteristic can be improved.

Further, the weight in the vicinity of the center of the diaphragm is larger than the weight in the outer peripheral portion of the diaphragm, the weight in the vicinity of the center of the diaphragm is non-rotationally symmetric with respect to the major axis and the minor axis, and the thickness distribution of the diaphragm. It is possible to improve the mid-range characteristics for each of the cases where the thickness is increased only near the center. Further, by increasing the gap width in the minor axis direction in the magnetic circuit with respect to the gap width in the major axis direction, it is possible to improve the production efficiency without lowering the efficiency of the magnetic circuit. Also, by providing a sliding portion on the voice coil or the magnetic circuit and sliding the sliding portion on the magnetic circuit or the voice coil,
The distortion of the diaphragm can be suppressed and the muddy sound can be suppressed. Further, the damper, which is a supporting member, can be omitted, and the speaker unit can be made thin.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of an embodiment of a speaker of the present invention.

FIG. 2 is a diagram showing characteristics of the embodiment of the speaker of the present invention.

FIG. 3 is a diagram showing a vibrating state of the embodiment of the speaker of the present invention.

FIG. 4 is a diagram showing an embodiment of a speaker of the present invention.

FIG. 5 is a diagram showing another embodiment of the speaker of the present invention.

FIG. 6 is a diagram showing another embodiment of the speaker of the present invention.

FIG. 7 is a diagram showing another embodiment of the speaker of the present invention.

FIG. 8 is a diagram showing effects of another embodiment of the speaker of the present invention.

FIG. 9 is a cross-sectional view of a conventional speaker.

FIG. 10 is a diagram showing frequency characteristics of a conventional speaker cabinet.

[Explanation of symbols]

1, 101, 101a, 101b ... Vibration plate 2 ... Bobbin 3 ... Damper 4 ... Center pole 5,5a ・ ・ ・ Joining part 6 ・ ・ ・ ・ ・ Voice coil 7: Magnetic pole 8 ・ ・ ・ Magnet 9 ・ ・ ・ Edge 10 ・ ・ ・ ・ ・ Frame 11 ・ ・ ・ Protective cap 12 ・ ・ ・ ・ ・ Cabinet 32 ・ ・ ・ ・ ・ Additional mass 33 ・ ・ ・ ・ ・ Sliding member 34 ・ ・ ・ ・ ・ York 35 ・ ・ ・ ・ ・ Kinshi Line 36 ・ ・ ・ ・ ・ Input terminal

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-284499 (JP, A) Actual opening Sho 53-133629 (JP, U) Actual opening Sho 63-38498 (JP, U) Actual opening Sho 57- 67490 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04R 9/06 H04R 7/12 H04R 9/02 102

Claims (7)

(57) [Claims] 1. A vibrating plate and a voice coil disposed in a part of the vibrating plate, wherein an outer peripheral portion of the voice coil of the vibrating plate can vibrate with a different vibration from an inner peripheral portion of the voice coil. The lowest resonance frequency of the part is lower than the lowest resonance frequency of the speaker. 2. A speaker having a non-rotationally symmetric diaphragm whose planar shape viewed from the vibration direction has a major axis and a minor axis, comprising a voice coil arranged in a part of the diaphragm, A speaker, wherein an outer peripheral portion of the voice coil can vibrate with a vibration different from that of an inner peripheral portion of the voice coil, and a minimum resonance frequency of the outer peripheral portion of the voice coil is lower than a minimum resonance frequency of the speaker. 3. A speaker having a non-rotationally symmetric diaphragm having a long diameter and a short diameter in a plan view viewed from the vibration direction, wherein the weight near the center of the diaphragm is larger than the weight of the outer peripheral portion of the diaphragm. A speaker characterized by that. 4. The weight near the center of the diaphragm is asymmetric with respect to the major axis and the minor axis.
The speaker described in. 5. The speaker according to claim 3, wherein the thickness distribution of the diaphragm is thick only in the vicinity of the center. 6. A speaker having a non-rotationally symmetric diaphragm whose planar shape viewed from the vibration direction has a major axis and a minor axis, comprising a magnetic circuit for supplying a magnetic flux to a voice coil, and the major axis in the magnetic circuit. A speaker characterized in that the gap width in the minor axis direction is larger than the gap width in the direction. 7. A speaker having a non-rotationally symmetric diaphragm whose planar shape viewed from the vibration direction has a major axis and a minor axis, comprising a magnetic circuit for supplying a magnetic flux to a voice coil, wherein the voice coil or the magnetic Provide a sliding part in the circuit,
A speaker, wherein the sliding portion is slid on the magnetic circuit or the voice coil.