JP2004343804A - Loudspeaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive loudspeaker capable of realizing flat characteristics, while extending its high-frequency reproduction limit. <P>SOLUTION: There is provided the loudspeaker comprising an arched diaphragm 1, which has a half vertical angle of 45°or smaller at a junction with a voice coil 3 and has a top in a position anterior to its inner and outer attaching portions and further whose outside-diameter portion is attached to a frame 5. Since the diaphragm 1 can be made low-profiled due to the arched shape by this configuration, while reducing the half vertical angle θ of the junction with the voice coil 3 of the diaphragm 1, an anterior chamber effect can be harnessed and; therefore a strength of the diaphragm is enhanced, so that split resonance becomes less likely to be generated. As a result, flat characteristics can be realized, while extending high-frequency reproducible limit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a loudspeaker used for a sound reproduction device or the like, which extends a high-frequency reproduction limit frequency.

Conventionally, as a means for extending a high-range reproduction limit frequency in a speaker, see, for example, The methods described in 157-158 are known. That is,
1. Reduce the weight of the vibration system.
2. Use a rigid diaphragm.
3. The half vertex angle of the diaphragm at the joint between the diaphragm and the voice coil is reduced.
It is effective.
Loudspeaker system, edited by Takeo Yamamoto (Radio Engineering Co., Ltd.) 157-158

  However, the conventional method has the following problems.

  First, if the weight of the vibrating system is reduced, the strength of the vibrating plate will decrease, so that split vibration of the vibrating plate will easily occur, and many large peak dips will occur in the characteristics. Absent.

  Further, if a diaphragm having high rigidity is used, the diaphragm material becomes expensive, and the high-rigidity material generally has a small internal loss and a large peak dip in characteristics.

Furthermore, if the half apex angle of the diaphragm at the joint between the diaphragm and the voice coil is reduced, a gentle and large peak dip occurs in the characteristics of the front chamber effect of the diaphragm.
And so on.

  Here, the anterior chamber effect means that a cavity is formed by the concave space in front of the speaker diaphragm, and the cavity causes resonance in a specific band, thereby causing a peak dip in the sound pressure frequency characteristic. To tell.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems and to provide an inexpensive speaker that achieves flat characteristics while extending the high-frequency reproduction limit.

In order to solve the above problems, the invention described in claim 1 of the present application is:
A frame, a voice coil, and a diaphragm joined to the frame and the voice coil, wherein a half vertex angle of a joint between the diaphragm and the voice coil is 45 ° or less, and the diaphragm is And an integrally formed having an arcuate cross section having a curved surface extending from the inner diameter mounting portion to the outer diameter mounting portion, and a top portion formed in front of both the inner diameter mounting portion and the outer diameter mounting portion. A speaker having a configuration and using a rubber-based adhesive as a joining means.

  With this configuration, the diaphragm can be made thinner due to the bow shape while reducing the half apex angle of the voice coil joint portion of the diaphragm, so that the anterior chamber effect can be suppressed. Further, the bow shape improves the strength of the diaphragm and makes it difficult for split resonance to occur.

The invention described in claim 3 of the present application
A speaker characterized in that a space on the back side of the diaphragm is sealed, and the diaphragm has a portion through which air flows, and air can flow only from this portion.

  With this configuration, air can flow through the diaphragm, and the stiffness of air in the space behind the diaphragm can be reduced. Since the low-frequency resonance is proportional to the square root of the stiffness, the low-frequency resonance can be reduced, that is, the low-frequency characteristics can be flattened.

  As described above, according to the loudspeaker of the present invention, the diaphragm can be made thinner due to the bow shape while reducing the half apex angle of the voice coil joining portion of the diaphragm, so that the front chamber effect can be suppressed. Will be possible. In addition, the bow shape improves the strength of the diaphragm and makes split resonance less likely to occur. Further, as the joining means, it is possible to use a rubber-based adhesive having a lower adhesive strength than the epoxy-based adhesive but having good workability. As a result, the material of the diaphragm can easily extend the high-frequency limit even if general pulp is used instead of an expensive high-rigidity material, and can realize flattening of characteristics.

  Further, according to the speaker of the present invention, it is possible to directly join the diaphragm and the voice coil without using an adhesive layer at the joint between the diaphragm and the voice coil. Can be extended.

  Further, according to the speaker of the present invention, air can be circulated through the diaphragm, and the stiffness of air in the space behind the diaphragm can be reduced. Since the low-frequency resonance is proportional to the square root of the stiffness, the low-frequency resonance can be reduced. As a result, the low-frequency characteristics can be easily flattened.

  Thus, the speaker of the present invention is of great industrial value.

  Hereinafter, embodiments of the speaker of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view illustrating a configuration of the speaker according to the present embodiment. This speaker is a high-frequency reproduction speaker having a diameter of 6 cm. In FIG. 1, reference numeral 1 denotes a 100% material pulp, which is a vibrating plate having a bow-like shape having a top portion 7 mm from the inner diameter mounting portion and 2.9 mm from the outer diameter mounting portion, and has a diameter of 19.2 mm from the inner diameter mounting portion. Up to R10, from φ19.2 mm to φ38.6 mm, and from R38.6 mm to the outer diameter mounting portion, that is, R7 up to φ50 mm. The position having a diameter of 38.6 mm is the top of the diaphragm, and this top is located forward of the diaphragm mounting portion. The half apex angle θ of the inner diameter is 27.5 °. Further, the half apex angle at the outer diameter attachment portion is 40 °.

  The outer peripheral portion of the diaphragm is fixed to a frame 5 having a thickness of 0.6 mm and a total height of 13.5 mm with a rubber adhesive. The frame 5 has no holes, and the back surface of the diaphragm is closed. The inner peripheral portion of the diaphragm is fixed to a voice coil 3 having a craft bobbin having a thickness of t0.05 mm with an adhesive, and the voice coil 3 is held at the center by a cotton cloth damper 4 whose outer peripheral portion is fixed to a frame 5. ing. Further, a center cap 2 having an outermost diameter of 17.5 mm, an outer diameter of a curved surface of 15.5 mm, a curvature of R8, and 100% pulp is fixed on the front surface of the diaphragm 1.

  Further, a field portion 6 composed of a ferrite magnet having an outer diameter of 45 mm and a thickness of 8 mm, an iron top plate, and a yoke is disposed below the frame 5. Furthermore, a voice coil wire wound around the lower portion of the voice coil 3 is inserted into a magnetic gap formed by the top plate and the yoke.

  The operation of the above configuration will be described. In the loudspeaker according to the present embodiment, the half-vertical angle of the joint of the diaphragm with the voice coil is 27.5 °, and the speaker has a bow shape having a top portion 7 mm from the inner diameter attachment portion and 2.9 mm ahead of the outer diameter attachment portion. It is composed of a bent diaphragm.

  The relationship between the high-frequency limit frequency (fh) and the half-vertical angle θ is described in the above-mentioned Non-Patent Document 1 “Speaker System, edited by Takeo Yamamoto”, p. The relationship shown in Equations (5 · 14) in FIGS. 157 to 158 and FIGS. 5 and 19, that is, in order to extend the high-frequency limit, it is effective to reduce the half-vertical angle. .

  However, in general, when the half apex angle is reduced, the overall height of the diaphragm increases, and a moderate and large peak dip occurs in characteristics due to a front chamber effect of a front space from the front surface of the diaphragm to the diaphragm mounting portion. Therefore, conventionally, the half apex angle is about 45 ° or more.

  On the other hand, in the present embodiment, since the diaphragm is bent in a bow shape, the half apex angle is sufficiently small as 27.5 °, and the front space from the front surface of the diaphragm to the top of the diaphragm is reduced. Can be smaller. Furthermore, the strength of the diaphragm can be improved by the bent shape of the diaphragm, and as a result, the occurrence of split resonance of the diaphragm can be suppressed.

  Also, regarding the half apex angle of the diaphragm inner diameter in the diaphragm shape of the configuration of the present application, by FEM simulation and actual measurement experiments, when the half apex angle is made larger than 45 °, the high frequency limit frequency exceeding the audible band 20 kHz is obtained. It was confirmed that elongation was difficult and a large peak dip occurred in the characteristics. In the present embodiment, specifications satisfying this condition are satisfied, and a flat characteristic can be realized while sufficiently extending the high frequency limit frequency.

  Hereinafter, the effect will be described with reference to actually measured characteristics. FIG. 2 shows the same half-vertical angle and diaphragm weight of the speaker of the first embodiment and the conventional speaker as those of the first embodiment in order to extend the high frequency limit shown in FIG. 3 shows the measured sound pressure frequency characteristics in comparison.

  2, in the conventional speaker, as shown by a characteristic B, a peak dip occurs due to the anterior chamber effect around 3 to 12 kHz. Further, due to the decrease in the diaphragm strength, a large number of large peak dips occur at 15 kHz or more due to the split resonance of the diaphragm. On the other hand, in the loudspeaker according to the first embodiment, as shown by the characteristic A, the 10 dB sound pressure is lower than the high frequency reproduction limit frequency (average sound pressure (average of 3, 4, 6, 8 kHz)). Frequency: 40 kHz (average sound pressure: 92 dB), which exceeds the audible band and can be set sufficiently high, and it is confirmed that the front chamber effect and the peak dip due to the split resonance of the diaphragm have been greatly reduced. it can.

  In the present embodiment, 100% pulp is used as the diaphragm material, but it goes without saying that the same effect can be obtained by using a material such as a film. Further, in the present embodiment, the diaphragm outer diameter attachment portion is attached using a rubber-based adhesive, but it goes without saying that the same effect can be obtained even if attachment is made with a material having high viscoelasticity such as butyl rubber. .

(Embodiment 2)
Next, a second embodiment of the speaker of the present invention will be described with reference to the drawings. FIG. 3 is a cross-sectional view illustrating a configuration of the speaker according to the present embodiment. The present embodiment is different from the first embodiment in that the shape of the joint portion of the diaphragm 7 with the voice coil and the integral shape with a center cap having a downwardly directed top portion are provided. That is, the entire circumference is tapered from a position of φ13.5 mm on the innermost radius of curvature R10 outside the voice coil of the diaphragm to a position of φ13.0 mm, and a radius of curvature from φ13.0 mm to the inside has a top in a downward direction. It is formed integrally with the center cap of R8. The voice coil 3 is joined to the tapered portion.

  The operation of the above configuration will be described. FIG. 4A is an enlarged view of a joint portion between the diaphragm 1 and the voice coil 3 shown in the first embodiment, and FIG. 4B is a diagram showing a joint between the diaphragm 7 and the voice coil 3 shown in the present embodiment. The enlarged view of the part is shown. In the speaker according to the present embodiment, as shown in FIG. 4B, when the diaphragm and the voice coil are fixed, a tapered portion on the diaphragm is inserted into the inner portion of the voice coil, and the adhesive 8 is eliminated. The diaphragm can be directly connected to the voice coil bobbin for fixing. On the other hand, the speaker according to the first embodiment has a conventional general joining structure. That is, as shown in FIG. 4A, the inner diameter of the diaphragm is fixed to the outer diameter of the voice coil bobbin, and a certain clearance is provided between the outer diameter of the voice coil and the inner diameter of the diaphragm in the manufacturing operation. If necessary, a layer of adhesive is necessarily formed in this area.

  Hereinafter, the effect will be described with reference to actually measured characteristics. FIG. 5 shows the measured sound pressure frequency characteristics of the speaker according to the second embodiment and the speaker according to the first embodiment in comparison.

  In FIG. 5, characteristic A is based on the speaker according to the first embodiment, and characteristic C is based on the speaker according to the second embodiment. In the loudspeaker according to the second embodiment, no adhesive layer having a low sound propagation speed is formed at the joint between the diaphragm and the voice coil.

  Therefore, as shown in FIG. 5, the high frequency limit frequency can be extended more than in the first embodiment. More specifically, in the first and second embodiments, the average sound pressure (described above) is 92 dB, and in the first embodiment, the high frequency limit frequency (described above) is 40 kHz. In No. 2, the frequency is 50 kHz, and it is possible to further extend the higher frequency limit of 10 kHz than in the first embodiment.

  In the second embodiment, the integrated center cap has the top portion in the downward direction, but it goes without saying that the same effect can be obtained even if the integrated center cap has the top portion in the upward direction. Further, in the second embodiment, the center cap is integrated, but the same effect can be obtained even if the center cap is not integrated and is attached to the diaphragm as a separate component as in the first embodiment. Needless to say.

(Embodiment 3)
Hereinafter, a third embodiment of the speaker of the present invention will be described with reference to the drawings. FIG. 6 is a front view showing the configuration of the speaker in the present embodiment. This embodiment is different from the first embodiment in that a material density is extremely low and a portion 9a through which air can flow is provided on the vibration surface of diaphragm 9. In other words, the inner portion of the diaphragm from φ40 mm has a density of 600 kg / m ³ , and the outer portion 9a indicated by hatching in the drawing has a density of 200 kg / m ³ to allow air to flow.

  The operation of the above configuration will be described. In the loudspeaker according to the third embodiment, the space on the back side of the diaphragm is sealed by the frame 5, but since the low-density portion 9a on the diaphragm that allows air to flow is provided, air can flow from this portion. .

  Generally, when the back surface of the diaphragm is sealed with a small volume, the stiffness of the air in the sealed space increases, so that the resonance in the low frequency band also increases (the magnitude of the low-frequency resonance is determined by the square root of the stiffness of the air). Proportional), a large peak is generated in the low-frequency characteristic in the sound pressure frequency characteristic. However, with the structure shown in the present embodiment, air can flow from the diaphragm, the stiffness of air is reduced, and low-frequency resonance can be reduced.

  Hereinafter, the effect will be described with reference to actually measured characteristics. FIG. 7 shows the measured sound pressure frequency characteristics of the speaker according to the third embodiment and the speaker according to the first embodiment in comparison. Here, the rear surface of the diaphragm in the first embodiment is configured to be sealed by a frame 5. In FIG. 7, characteristic A is based on the speaker of the first embodiment, and characteristic D is based on the speaker of the third embodiment. In the loudspeaker according to the third embodiment, the stiffness of the air behind the diaphragm is reduced due to the flow of air from the diaphragm, and as a result, the peak due to the low-frequency resonance can be reduced as indicated by the characteristic D. .

  In the third embodiment, the low-density portion is provided on the diaphragm. However, as shown in FIG. 8, the same effect can be obtained even if the diaphragm 10 is provided with a hole 10a having a diameter of 1 mm. Needless to say.

  INDUSTRIAL APPLICABILITY The speaker of the present invention is useful as a speaker that realizes inexpensive and flat frequency characteristics while extending a high-frequency reproduction limit frequency.

Sectional view of speaker according to Embodiment 1 of the present invention FIG. 5 is a diagram showing sound pressure frequency characteristics of the speaker according to the present invention and a conventional speaker. Sectional view of speaker according to Embodiment 2 of the present invention Enlarged view of the joint between the speaker diaphragm and the voice coil FIG. 4 is a diagram illustrating a sound pressure frequency characteristic of the speaker according to the first and second embodiments of the present invention. Front view of speaker according to Embodiment 3 of the present invention FIG. 4 is a diagram illustrating a sound pressure frequency characteristic of the speaker according to the first and third embodiments of the present invention. Front view of speaker showing application example of Embodiment 3 of the present invention Cross section of conventional general speaker

Explanation of reference numerals

Reference Signs List 1 diaphragm in first embodiment 2 center cap 3 voice coil 4 damper 5 frame 6 field portion 7 diaphragm in second embodiment 8 adhesive 9 diaphragm 9a in third embodiment 9a diaphragm in third embodiment Low-density portion 10 Diaphragm 10a in application of Embodiment 3 10a Hole in diaphragm in application of Embodiment 3 θ Half-vertical angle of diaphragm

Claims (5)

A frame, a voice coil, and a diaphragm joined to the frame and the voice coil,
The half vertex angle of the joint between the diaphragm and the voice coil is 45 ° or less,
The diaphragm has an arcuate cross section having a curved surface extending from the inner diameter mounting portion to the outer diameter mounting portion, and a top portion formed in front of both the inner diameter mounting portion and the outer diameter mounting portion. Has an integrally molded configuration,
A speaker using a rubber adhesive as a joining means. A frame, a voice coil, and a diaphragm joined to the frame and the voice coil,
The half vertex angle of the joint between the diaphragm and the voice coil is 45 ° or less,
The diaphragm has an arcuate cross section having a curved surface extending from the inner diameter mounting portion to the outer diameter mounting portion, and a top portion formed in front of both the inner diameter mounting portion and the outer diameter mounting portion. It is integrally molded,
The voice coil has a substantially cylindrical shape, and has a configuration in which an end thereof and an inner diameter mounting portion of the diaphragm are joined,
A speaker using a rubber adhesive as a joining means. 3. The speaker according to claim 1, wherein a space on the back side of the diaphragm is sealed, and the diaphragm has a portion through which air flows, and air can flow only from this portion. 4. The loudspeaker according to claim 3, wherein a portion through which air flows is disposed near an outer peripheral portion of the diaphragm. The speaker according to claim 3, wherein a member having a lower density than an inner peripheral portion is used near an outer peripheral portion of the diaphragm.

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