JPH0638678B2 - Speaker - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a speaker, and in particular, a small amplitude of a vibration source such as a voice coil is amplified by a mechanical amplifying means such as a lever to a diaphragm. It relates to a speaker that transmits.

2. Description of the Related Art In recent years, audio equipment has been significantly miniaturized due to the progress of semiconductor technology and the advent of high-performance small circuit components. Speaker systems are becoming smaller regardless of home needs or in-vehicle systems, but there is a problem with the acoustic characteristics in the low frequency range.

That is, the on-axis sound pressure (P _r ) and the amplitude (X) of the speaker are given by the following equations.

Where ρ ₀ is the density of air, ω is the vibration angular frequency, a is the effective radius of the diaphragm, r is the distance between the speaker and the microphone, V is the speed of the diaphragm, X is the amplitude of the diaphragm, and A is the force coefficient. E is the input voltage of the signal, R _E is the electrical resistance of the speaker, M _S is the vibration system mass of the speaker, M _a is the load mass of air, Q ₀ is the sharpness of resonance, ₀ is the minimum resonance frequency, and is the frequency. .

Therefore, the efficiency decreases as the effective radius of the diaphragm decreases. In addition, according to the equation (2), the amplitude of the diaphragm is inversely proportional to the square of the frequency when it is ₀ or more, and therefore becomes large in the low range.
However, if the voice coil winding width is reduced in order to improve efficiency, the amplitude range of the voice coil is narrowed, so that a distortion component is generated in the low frequency range. As a driving method capable of large amplitude, there is a speaker using a long voice coil, but the utilization factor of the voice coil loop length is deteriorated and the efficiency cannot be improved. Therefore, in order to improve efficiency and reduce the distortion rate, it is necessary to amplify the amplitude of a small voice coil and transmit it to the diaphragm.
As shown in Japanese Patent Publication No. 9826, there is one using a lever.

Hereinafter, the above-described conventional speaker will be described with reference to the drawings.

FIG. 5 shows a cross section of a conventional speaker using an amplitude amplification mechanism. In FIG. 5, 1 is a pot yoke, 2
Is a magnet, 3 is a pole piece, and a pot yoke 1
The pole piece 3 holds the magnet 2 and forms an annular magnetic gap 4. Reference numeral 5 is a support table fixed to the upper surface of the pole piece 3, and has a bearing portion of a fulcrum a so that the lever 6 can rotate. In the magnetic gap 4, there is a voice coil bobbin 8 around which a voice coil 7 that reciprocates in response to a signal input is wound. The upper end of the voice coil bobbin 8 is a fulcrum a of the lever 6.
It is held by the lever 6 at a connection point b which is rotatable by a distance of ₁ to ₁ . Furthermore, ₂ from the fulcrum a (however, ₂ >
There is also a pivotable coupling point c at the distance ₁ ) and a reinforcing ring 9 is attached. Reference numeral 10 denotes a substantially frustoconical diaphragm which is fixed to the reinforcing ring 9 at the bottom.
A damper for supporting the voice coil bobbin 8 and an edge for supporting the diaphragm 10 are not shown.

The operation of the conventional speaker configured as described above will be described below.

When a signal current flows through the voice coil 7 in the magnetic gap 4 formed by the pot yoke 1, the magnet 2 and the pole piece 3, the voice coil 7 and the voice coil bobbin 8
The connection point b of is changed by x. Therefore, the lever 6 rotates about the rotatable fulcrum a provided on the support 5. At this time, the displacement X of the connecting point c of the lever 6 is Given by the displacement is amplified ₂ / _1x. Thus a reinforcing ring 9 having a coupling point c, the vibration plate 10 which is fixed thereto will have been amplified _2/1 times the displacement of the voice coil 7.

Problems to be Solved by the Invention However, in the above configuration, since the lever rotates about the fulcrum a, the connecting points b and c are ₁ (1-cos θ) and ₂ (1-cos θ) in the central direction, respectively. Since it moves only by itself, bending force is applied to the voice coil bobbin and the reinforcing ring, and the voice coil comes into contact with the pole piece or the pot yoke to generate an abnormal sound, which is not suitable as an amplitude amplification mechanism.

In view of the above-mentioned problems, the present invention provides a speaker that reproduces a low frequency range efficiently and with high fidelity.

Means for Solving the Problems To achieve this object, a speaker of the present invention is provided with a regular polygonal central support part in which a voice coil bobbin is inserted and fixed in a central hole, and is bent around each outer periphery of the central support part. A plurality of bendable / extendable quadrangular tetrahedrons that are provided with reinforcing ribs in the direction of the short side, and a first quadrangular tubular body and an inner circumferential side coupling portion of the first quadrangular tubular body, and A second quadrangular cylinder which is bendable and extensible with a part of two sides extending from the connecting part as a common part and which is provided with reinforcing ribs in the direction of the short side is provided inside the first quadrangular cylinder. The first quadrangular cylinder is connected at its outer peripheral portion to the outer peripheral support through a bent portion. The outer peripheral end of the outer peripheral support, the outer peripheral end of the diaphragm, and the inner peripheral end of the edge are formed. And a structure in which the outer peripheral portion of the second rectangular tubular body is fixed via a bent portion. Has become.

Action With this configuration, when the driving force of the voice coil is applied to the inner peripheral portion of the first rectangular cylindrical body, a rotational movement occurs around the outer peripheral portion of the fixed second rectangular cylindrical body, and by the lever principle, Since the displacement of the outer peripheral portion of the first rectangular cylinder is increased and the displacement of the diaphragm is also increased as compared with the displacement of the voice coil, reproduction in the low frequency range is particularly good. In addition, since the rectangular faces that form the first and second rectangular cylinders are provided with the reinforcing ribs in the short side direction, the rigidity is greater than that without the reinforcing ribs and is less likely to be deformed.
The driving force of the voice coil can be faithfully transmitted to the diaphragm. Further, at this time, since both the inner peripheral portion and the outer peripheral portion of the first rectangular tubular body can be moved only in the vertical direction, the voice coil and the vibration plate due to the rotational movement of the lever as shown in the above-mentioned conventional example are formed. The displacement of the joint portion of the lever is eliminated, and the gap rubbing of the voice coil can be prevented. Further, since the first rectangular cylinder and the second rectangular cylinder can also serve as a damper that holds the position of the voice coil, there is an advantage that the damper can be simplified and the configuration of the speaker can be simplified. It is a thing.

Embodiment One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of a speaker in one embodiment of the present invention, FIG. 2 is a plan view of a further main part thereof, and FIG. 3 is a perspective view of a first rectangular cylinder provided with reinforcing ribs. FIG. 4 is a schematic sectional view showing the operation. 1, 2, 3,
In FIG. 4, 11 is a frame, 12 is a diaphragm, and 13
Is an edge in which the inner peripheral edge is attached to the outer peripheral edge of the diaphragm 12 and the outer peripheral edge is fixed to the frame 11, and 14 is a voice coil 14a in which the lower edge is inserted into a magnetic gap (not shown) of a magnetic circuit.
A voice coil bobbin has a central support portion 15 having a voice coil bobbin 14 fixedly inserted in a central hole and having a bent portion a on each outer periphery, and 16 a inner supporting portion connected to the bent portion a and an outer peripheral portion to a bent portion c. The connected first quadrangular cylindrical body, 17 is a reinforcing rib provided in the short side direction of the quadrangular prism that composes the first quadrangular cylindrical body 16, 18 is an outer peripheral support portion whose inner periphery is connected to the bent portion c, and 19 is A fixed base whose lower end is fixed to the frame 11, 2
Reference numeral 0 is a second rectangular tubular body in which a part of the two sides on the inner peripheral side of the first rectangular tubular body 16 are common and the outer peripheral end is fixed to the fixed base 19 via the bent portion b.

The operation of the speaker configured as above will be described below. First, when a reproduction signal current is passed through the voice coil 14 whose lower end is inserted in the magnetic gap, a driving force is generated by Fleming's left-hand rule, and the voice coil 14 vibrates in the vertical direction. This vibration is transmitted to the bent portion a of the central support portion 15 and the inner peripheral end portion of the first rectangular tubular body 16 also vibrates vertically. At that time, with the outer peripheral end portion of the second quadrangular cylinder 20 as the center, the first quadrangular cylinder 16 and the second quadrangular cylinder 20 reciprocally rotate while bending and stretching so that their diagonal lengths change. The outer peripheral support portion 18 connected to the outer peripheral end of the first rectangular tubular body 16 via the bent portion b vibrates vertically, and the diaphragm 12 fixed to this vibrates vertically to generate a sound.

Here, the movements of the first rectangular tubular body 16 and the second rectangular tubular body 20 in the operation in the above configuration will be described with reference to FIG. In FIG. 4, the solid line shows the stationary state and the broken line shows the displaced state. When the voice coil 14 is displaced downward by X, the first rectangular tubular body defg is deformed and d'e'f '.
g ', and the second rectangular cylinder dijh is also deformed to d'i'.
j′h ′, and the outer peripheral support 18 is displaced by Y. At this time, since the first rectangular tubular body 16 and the second rectangular tubular body 20 are always similar in shape, the relationship between the displacement X of the voice coil 14 and the displacement Y of the outer peripheral support portion 18 follows the lever principle according to the following formula. It is represented by.

Therefore, the displacement of the vibration plate 12 connected to the outer peripheral support portion 18 is calculated by subtracting the diagonal length of the second rectangular tubular body from the diagonal line (dj) of the second rectangular tubular body 20 and the diagonal length of the first rectangular tubular body 16. It is magnified by the ratio of the tatami (jf) compared to the displacement of the voice coil 14.

As described above, according to the present embodiment, in the speaker provided with the mechanical amplification mechanism that expands the displacement of the diaphragm according to the lever principle, instead of the rod-shaped lever, the bendable and extensible first rectangular tubular body 16 is provided. By using an amplifying mechanism composed of a second square tubular body 20 in which a part of the two sides on the inner peripheral side of the first square tubular body 16 is common and the outer peripheral end is rotatably fixed, As shown in FIG. 4, the first rectangular tube body 16,
The second quadrangular tubular body 20 holds the parallelogram while bending and stretching, and moves like a pantograph, and the voice coil 14 and the diaphragm 12 do not move in the lateral direction but can move only in the vertical direction. As described above, the position of the end of the lever 6 shifts toward the center due to the rotational movement, and the bending force is applied to the voice coil bobbin 8 and the diaphragm 10, so that the voice coil 7 does not come into contact with the pole piece 3 or the pot yoke 3 and no abnormal noise is generated. It is a thing. Further, as shown in FIG. 3, the first rectangular tubular body 16 and the second rectangular tubular body 20 are arranged in the direction of the short sides, that is, in the direction acting as a lever when the driving force from the voice coil 14 is applied to the rectangular faces. Since the reinforcing rib 17 having a V-shaped cross section is provided, the rigidity of the quadrangular prism is high. Therefore, as compared with the speaker having the same structure without the reinforcing rib, the first rectangular cylindrical body 16 which replaces the lever is provided.
And the deformation of the second rectangular cylinder is small, and the voice coil 1
The driving force of 4 can be accurately transmitted to the diaphragm 12,
High fidelity reproduction becomes possible. Further, the first rectangular tubular body 16 and the second rectangular tubular body 20 are the voice coil 14
Since it has a function as a damper that moves while maintaining the position of 1, the damper can be omitted and the configuration as a speaker can be simplified.

EFFECTS OF THE INVENTION The present invention provides a first quadrangular cylinder body and a first quadrangular cylinder body, which are composed of a quadrangular prism body that can be bent and extended instead of a lever and provided with reinforcing ribs having a substantially V-shaped cross section in the short side direction. A second rectangular parallelepiped body that has a part of two sides on the inner peripheral side in common and the outer peripheral end is rotatably fixed and is bendable / extendable, and has reinforcing ribs having a substantially V-shaped cross section in the short side direction. The voice coil and diaphragm can be vibrated only in the vertical direction by using the amplifying mechanism composed of the square tubular body, and the displacement of the voice coil is amplified and transmitted to the diaphragm according to the lever principle. In addition to enabling good bass reproduction, the rigidity of the first and second quadrangular cylinders, which replace the levers, is made up of quadrangular prisms having V-shaped cross-section reinforcing ribs. Higher fidelity playback because it does not deform high Of.

Further, the amplification mechanism of the present invention also has a function of holding the voice coil at the center position, and at the same time, it can play the role of a damper in the conventional electrodynamic speaker, so that the speaker structure can be simplified. , An excellent speaker can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a speaker according to an embodiment of the present invention, FIG. 2 is a plan view of a further main part thereof, and FIG. 3 is a perspective view of a first rectangular cylinder provided with reinforcing ribs. FIG. 4 is a schematic sectional view showing the operation, and FIG. 5 is a sectional view of a conventional speaker. 14 ... Voice coil bobbin, 15 ... Central support part, 1
6 ... First square tubular body, 17 ... Outer peripheral support portion, 18 ...
Second rectangular cylinder, a, b, c ... Bent portion.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kosaku Murata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Mitsuru Iejo, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-62-76394 (JP, A)

Claims (1)

[Claims] 1. A regular polygonal center support part in which a voice coil bobbin is inserted and fixed in a central hole, and a plurality of bendable and extendable short sides connected to each outer periphery of the center support part through bent parts. Direction of the first rectangular body, which is composed of a tetrahedron provided with reinforcing ribs having a substantially V-shaped cross section, a connecting portion on the inner peripheral side of the first rectangular tubular body, and two sides extending from the connecting portion. Is a common part, and has a diagonal length shorter than half the diagonal length of the first rectangular tubular body, and is bendable / extendable.
A second quadrangular tubular body composed of a quadrangular prism provided with character-shaped reinforcing ribs is formed inside the first quadrangular tubular body, and the first quadrangular tubular body has an outer peripheral portion with a bent portion interposed therebetween. The outer peripheral end of the outer peripheral support and the outer peripheral end of the diaphragm and the inner peripheral end of the edge are fixed to each other.
A speaker having a mechanical amplification mechanism, characterized in that the outer peripheral portion of the rectangular tubular body is fixed via a bent portion.