JPS63299500A - Speaker - Google Patents

Abstract

PURPOSE:To widen a reproducing band by arranging mutually in parallel two approximately rectangular voice coils so that the central axis of respective short axes can pass through two points of four intersections of the section of the oscillation mode of secondary and tertiary resonances of a square plat diaphragm. CONSTITUTION:A voice coil 2 is of an approximately rectangular shape and a flange part is provided at the peak part of a bobbin. Two coils 2 are provided with two pieces, and respective coils 2 are joined so that the central line of the short side of the coils 2 can pass through the intersection of the nodal line and nodal circle of the oscillation mode of secondary and tertiary resonances of a square diaphragm 1. Thus, with two voice coils, the section of a special oscillating mode is not driven, the shape and arrangement of the voice coils are devised so as to drive many sections and the full-surface driving is equivalently executed. Thus, a reproducing band is widened and a peak dip can be made into a sound pressure frequency characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure for improving a speaker, and relates to a method of coupling a square flat diaphragm and a voice coil bobbin.

[Conventional technology]

As a speaker using a conventional square sand-inch diaphragm, there are references (for example, APM Speaker System Radio Technology 1, March 1978 issue, pp. 147-158).
), four or one voice coil (bobbin) is connected to the nodes (nodal lines and nodal circles) of the resonant mode of resonance, and nodal drive (also called node drive or mode drive) is performed. The aim is to widen the playback band. Specifically, the resonance vibration mode of a square thin plate is shown in FIG. In the above-mentioned literature, Fig. 3 A, B
The relationship between the diaphragm 1 and the voice coil 2 is as shown in FIGS. 4A and 4B. The configuration shown in FIGS. 3A and 3B has four points at the intersection 3 (hereinafter also referred to as the driving point C) of the node line A and the node circle mouth of the resonance vibration modes (b) and (c) shown in FIG. The voice coil 2 is connected to perform node drive. At this time, the length L of one side of the square diaphragm is 27 marks, the diameter 2r of the nodal hole passing through the center of the four voice coils (intersection 3) is 21.3 cm, and the length L of one side of the diaphragm is Sashito Bushi Enguchi (
Hereinafter, the relationship between the diameter 2r of the driving circle 2 (also referred to as driving circle 2) is 2r/L.
:0.789, good results were obtained.

Further, in the configuration shown in FIGS. 4A and 4B, the voice coil 2 is connected to the nodal opening of the resonance vibration mode (c) shown in FIG. 2 to perform nodal drive. At this time, the length L of one side of the square diaphragm is 11.4 cm, and the diameter 2r of the voice coil is 10 cm.
The relationship between the length L of one side of the diaphragm and the diameter 2r of the voice coil is 2r/L=0.877. Ideally, it would be sufficient to drive with four voice coils 2 as shown in FIG. 3AB, but as the diaphragm 1 becomes smaller, the voice coils and magnetic circuit must be made relatively smaller.

If the diaphragm 2 is made smaller, it becomes difficult to obtain the driving force F necessary to drive the diaphragm 2, so the diaphragm 2 is driven by a single large-diameter voice coil, as shown in FIGS. 4A and 4B. Figure 3 A, B and 4
In figures A and B, the length L of one side of the diaphragm 1 and the diameter 2 of the nodal hole
The ratio 2r/L of r is different, but this is because it changes depending on the conditions (stiffness, mass) of the edge suspension 4 arranged around the diaphragm 1. By the way, 2 of the square thin plate with peripheral freedom without edge suspension 4
r/L is 0.72.

, 3.

However, the characteristic of the above-mentioned nodal drive is that if the driving point C and the driving circle 2 correspond to the nodal line A and the nodal circle mouth of the vibration mode of resonance shown in Fig. 2, the resonance below that point disappears. be. However, the drawback of this driving method is that since a specific node is driven, higher-order resonances remain, resulting in a sound pressure frequency characteristic having a peak P and a dip t as shown in FIG.

The result is a complex system with multiple speaker units.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology has a problem in that the reproduction band is made wider and flatness is not taken into consideration, and it is difficult to reproduce the entire audible band with - number of speakers.

The purpose of the present invention is to reduce the peak P and the dip t by dispersing the sound pressure frequency characteristics so that they do not occur sharply in a concentrated manner. By making it shallower, the apparent purpose is to widen the playback band and reproduce the entire audible band with one speaker.

, 4.

[Means for solving problems]

The object of the present invention is to concentrate the driving points or driving circles for transmitting the driving force to the diaphragm by the voice coil on the nodal lines and specific parts of the nodal circles of the resonance vibration mode of the square diaphragm shown in FIG. This is achieved by not doing so.

[For production]

The above purpose is to configure the voice coil so that the driving point or driving circle is in contact with many nodes so that the driving point or driving circle does not concentrate on the nodes of this specific resonance vibration mode as in the conventional example.

To achieve this, a plurality of voice coils may be arranged over the entire surface of the diaphragm to perform so-called full-surface drive. However, in this method, the number of magnetic circuits associated with the voice coil increases, the configuration becomes complex, and the cost increases.

In the present invention, two voice coils are used, and the shape and arrangement of the voice coils are devised to drive many nodes, rather than driving nodes in a specific vibration mode, and the entire surface is driven isometrically. By configuring to do this, it is possible to obtain a sound pressure frequency characteristic with a wide reproduction band and a small peak/dip.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIGS. 1A, B, and C are diagrams showing a speaker according to an embodiment of the present invention. Figure 1A is a front view, Figure 1B is a front view.

C is a cross-sectional view. 1 has aluminum honeycomb as the core material,
This is a square sand inch diaphragm that uses aluminum foil as the surface material. 2 is the voice coil (including the bobbin), 4
-5- is an edge that supports the vibration system consisting of a diaphragm 1 and a voice coil 2, a yoke plate 6, and a magnet 7.
8 is a frame that houses the vibration system and the magnetic circuit. As shown in the perspective view of FIG. 6, the voice coil 2 has a rounded rectangular shape. Further, a flange portion 2' is provided at the top of the voice coil bobbin to facilitate connection to the diaphragm 1.

As shown in FIG. 1, two voice coils 2 are provided and electrically connected in series or in parallel. Each voice coil 2 is connected to the second part of the diaphragm 1 shown in FIGS.
The intersection point 3 of the nodal line A and the nodal circle mouth of the vibration mode of the next and third resonance is the short side of the voice coil 2 (width Uf of the voice coil 2)
It is joined so that the center line t passes through it.

Also, the width of the voice coil 2 and the long side of the voice coil 2 (
voice coil length, ) and two voice coils 2
As a result of considering the respective gap widths 〇', when the length Q of the voice coil 2 is 3 times the width ゜ and the voice coil interval W' is zo equal to the width ゜ of the voice coil 2,
This is equivalent to driving all the nodes of the resonance vibration mode from the first order (σ) to the ninth order (i) shown in Figure 2.
Good sound pressure frequency characteristics as shown in FIG. 7 were obtained. In addition, a diaphragm 1 and a voice coil 2 as shown in FIG.
If the relationship is as follows, the sound pressure frequency characteristic will be the same, a peak P and a dip L will occur, and the reproduction band will be narrow.

At this time, one side of the diaphragm 1 is 8.4 cm, and the thickness is 2 cm.

Also, the relationship between the width V and length α of the voice coil 2 is Q/ = 2
6. Relationship between the distance between the two voice coils 2 and the voice coil width 4 Even when Lr was set to 1 to 4, quite good sound pressure frequency characteristics were obtained.

Furthermore, the high-frequency resonance frequency 5K becomes higher when the length Q direction of the voice coil 2 is aligned with the direction in which the aluminum honeycomb, which is the core material of the sandwich diaphragm 1, extends.

Embodiment 2 This embodiment is a method of making the connection between the diaphragm 1 and the voice coil 2 stronger and the bobbin 2' of the voice coil 2 stronger in the method of the present invention described in the embodiment 1.

Figure 8 A, B, and C show the voice coil 2-1 and bobbin 2-
2. Voice coil assembly including collar part 2-3? It is a perspective view and a sectional view showing the composition of -.

The bobbin 2-2 is, for example, a thin plastic plate (thickness t
= 0, 5-1, 5 + nm) are formed by vacuum forming as shown in FIG. 8A. At this time, the vacuum suction direction is the base of the slit 9 (voice coil, 8).

The part where 2-2 is inserted and joined) is the empty part 2-3. The slit 9' reinforces the slit 9 into which the voice coil 2-1 is inserted and joined, and the two voice coils 2-1
This has the effect of reinforcing the space between the slits 9 where the slits 9 are inserted. When the slits 9°9'' are provided, slits 10 are provided between the magnetic circuits, as shown in FIG. 1C.

With this configuration, the strength of the bobbin 2' of the voice coil 2 shown in FIGS. Since the driving force F is sufficiently transmitted to the diaphragm 1, high frequency distortion is also reduced.

Embodiment 3 This embodiment improves the method of joining the bobbin and voice coil in the method of the present invention described in Embodiment 2. In the second embodiment, as shown in FIGS. 8B and 8C, the bobbin 2-2 surrounds both sides of the voice coil 2-1, and in order to further increase the amplitude, the height of the bobbin 2-2 is It becomes necessary to take a larger size, and as a result, it becomes deep drawing and the bobbin 2-
The thickness t6 of 2 itself becomes thicker. And voice coil 2-
The width of the slit 9 into which the magnetic circuit 5 is inserted and joined increases, and the magnetic gap length Qg of the magnetic circuit 5 increases.

Further, since the bobbin 2-2 is also thick and heavy, it has the disadvantage of lowering the output sound pressure level.

Therefore, in this embodiment, in order to reduce the mass and further narrow the magnetic gap length 11g without deteriorating the rigidity of the voice coil assembly, the bobbin 2-2 is installed as shown in FIGS. 9A, B, and C. was divided into two parts. Here,
The bobbin 2-2' directly winds the voice coil 2-1, and the bobbin 2-2' has the role of joining and reinforcing the voice coil 2-1 and the diaphragm 1. Bobbin 2-
2 has a lower height and a thickness t, and 4 is the bobbin 2 of Example 2.
-2 can be made 30 to 50% thinner and lighter in weight. Also, since the height h can be reduced, the material can be changed from plastic film to aluminum foil, and bobbin 2-2
If aluminum foil is used as the material of the voice coil assembly 2, the voice coil assembly 2 can be strengthened, the permissible input to the voice coil 2-1 can be increased, and the output sound pressure level can also be increased.

As a result, the sound pressure frequency characteristics are flat and the reproduction band is widened.
A speaker with reduced harmonic distortion can be obtained.

〔Effect of the invention〕

According to the present invention, the coupling between the diaphragm and the voice coil becomes strong, and the driving force generated by the voice coil is not concentrated on a specific part of the diaphragm, but is transmitted to the entire surface of the diaphragm. , which has the effect of dispersing resonance without causing singular resonance.

As a result, even if resonance occurs, a speaker with small peaks and dips, flat sound pressure frequency characteristics, and a wide reproduction band can be obtained.

In this case, an aluminum honeycomb is used as the core material of the sandwich-structured diaphragm, but the core material such as a honeycomb or foam material using paper or resin film, and the surface material are FRP thin plates or plastic films other than aluminum foil. Similar effects can be obtained with the sandwich structure used.

[Brief explanation of drawings]

FIG. 1 is a front view and a sectional view of a speaker according to an embodiment of the present invention, and FIG. 5 is a diagram of sound pressure frequency characteristics of a conventional speaker and a sound pressure frequency characteristic aimed at by the speaker of the present invention. 6 is a perspective view of the voice coil of the speaker according to the embodiment of the present invention shown in FIG. 1, and FIG. 7 is a sound pressure frequency characteristic diagram of the speaker according to the embodiment of the present invention shown in FIG. Figures 8 and 9
The figures are a perspective view and a sectional view showing the voice coil and bobbin of two other embodiments of the present invention. 1...Diaphragm, 1...Voice coil assembly. 2-1...Voice coil, 2-2 or 2-2'...
Bobbin, 3...intersection of knots, 4...edge, mutual...
magnetic circuit. 9...Frame. 3rd mouth (c) 躬 4圀(B) CB) 庬8layer (c) CB) Hoi

Claims (1)

[Claims] 1. In a speaker equipped with a square flat diaphragm, two voice coils, and a magnetic circuit, the central axis of the short axis of each of the two approximately rectangular voice coils is
A speaker characterized in that two voice coils are arranged parallel to each other so as to pass through two points of four intersections of nodes of vibration modes of second and third resonances of a square flat plate diaphragm.