JP3166399B2 - Speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker used for a sound reproducing apparatus or the like.

[0002]

2. Description of the Related Art A typical conventional example will be described with reference to FIG. FIG. 7 is a half cross-sectional view of a conventional speaker. A ring-shaped main magnet 2 magnetized in the thickness direction is attached to the vicinity of an outer peripheral edge of an upper surface of a bottom plate 3 which is a disk-shaped magnetic material. A top plate 1, which is a magnetic material manufactured by punching, is mounted on the bottom plate 3, and a ring-shaped sub-magnet 4 magnetized in a direction opposite to the main magnet 2 is mounted near an outer peripheral edge of a lower surface of the bottom plate 3. . A yoke cover 5 is attached so as to cover from the top plate 1 to the sub magnet 4. Also, top plate 1
A frame 6 is mounted on the upper surface of the frame 6. Further, a wire gap portion 7a having an outer periphery fixed to the frame 6 and supported by a suspension 8 is provided in a magnetic gap portion formed by a center pole portion of the top plate 1 and the bottom plate 3. There is a voice coil 7 having. The width of the wire loop portion 7 a is smaller than the thickness of the top plate 1. This is generally referred to as a short voice coil system, as shown on page 163 of "Speaker System (1)" (published by Takeo Yamamoto, published by Radio Engineering Co., Ltd.), first published on July 15, 1977. That is, the thickness of the top plate 1 is made as large as possible, so that the magnetic flux density generated in the range in which the wire ring portion 7a of the voice coil 7 moves in the magnetic gap portion. And the driving force received by the wire loop portion 7a is always made uniform.Furthermore, the outer periphery is fixed to the frame 6 at the upper part, and the inner periphery is fixed to the voice coil 7, The structure was such that the diaphragm 9 having the dust cap 10 was attached at the center.

FIG. 8 shows a magnetic flux density distribution in a magnetic gap portion of a conventional speaker. The horizontal axis indicates the magnitude of the magnetic flux density, and the vertical axis indicates the measurement distance. The magnitude of the magnetic flux density is represented by a curve A, and is distributed uniformly within the thickness of the top plate 1.

[0004]

However, in the above-mentioned conventional structure, in order to increase the thickness of the top plate, the size of the punching die is increased, the material cost is increased by increasing the size of the top plate, and the size of the magnetic circuit is increased. There is a problem in that the thickness of the top plate is limited. Therefore, if it is attempted to widen the constant range of the driving force when the voice coil vibrates up and down in the drawing, the length of the wire ring of the voice coil becomes short, the driving force itself decreases, and the output sound pressure decreases. Otherwise, the range of movement of the voice coil loop portion from within the uniform magnetic flux density distribution would exceed the range, causing problems such as an increase in distortion due to the asymmetry of the magnetic flux density distribution.

The present invention solves such a conventional problem,
It is an object of the present invention to provide a high-efficiency, low-distortion speaker at low cost while suppressing an increase in material cost due to an increase in the size of a top plate.

[0006]

In order to achieve this object, a loudspeaker according to the present invention faces a magnetic gap.
The width of the gap opposing part is bonded to the magnet
The thickness of the gap opposing portion is larger than the thickness of the bonding portion.
Is an integrated bent shape thinner than the thickness of the bonding portion,
The top surface of the gap-facing part is closer to the top than the top surface of the bonding part.
Magnetic with top plate that does not pop out
A circuit having a circuit and a winding width smaller than the width of the gap opposing portion.
A chair coil is arranged in the magnetic gap, and
Occurs at the gap opposing part over the vibration region of the coil
Is characterized in that the generated magnetic flux density is substantially uniform .

The speaker of the present invention has a magnetic gap.
The width of the gap facing part facing the part is
The thickness is larger than the thickness of the
The thickness of the opposing part is smaller than the thickness of the bonded part.
In a curved shape, the top surface of the gap opposing portion is
The gap does not jump out from the top surface in the direction of the top surface.
As the thickness of the facing part decreases as it approaches the tip,
A magnet with a substantially linear taper on the magnet side
A magnetic circuit having a gap plate;
Voice coil with a winding width smaller than the width of the
It is characterized in that it is arranged in the loop part .

Further, the speaker of the present invention has a magnetic gap.
The width of the gap opposing part facing the
The thickness is larger than the thickness of the bonded portion,
Integral type where the thickness of the opposite part is smaller than the thickness of the bonded part
The top surface of the gap opposing part is the bent part
Without protruding from the top of the
The gap increases as the magnetic gap dimension approaches the top side.
Toe that has a substantially straight taper shape
A magnetic circuit having a gap plate;
Voice coil with a winding width smaller than the width of the
It is characterized in that it is arranged in the loop part .

[0009]

According to the present invention, the width of the portion facing the magnetic gap portion is increased regardless of the thickness of the magnet bonding portion, so that the uniform magnetic flux density distribution can be maintained over a wide range. In addition, the waste of the material of the top plate can be eliminated, and the material cost can be significantly reduced. Also, since the thickness of the part facing the magnetic gap part is reduced,
The restriction on the inner diameter of the magnet used is relaxed, and the degree of freedom in selecting the magnet is increased. That is, there is no adverse effect that the magnet size is inevitably increased due to the restriction on the inner diameter, and the magnetic circuit can be reduced in size.

When the magnetic flux density distribution in the magnetic gap portion is viewed, the magnitude of the magnetic flux density in the portion of the top plate facing the magnetic gap where the thickness is smaller than the thickness of the magnet bonding portion is different from that of the other portion. Although it is slightly smaller than the part, the thin part is tapered downward without changing the width of the magnetic gap, so the decrease in magnetic flux density in this part is alleviated, and a more uniform magnetic flux density distribution is obtained. can get.

Further, of the top plate facing the magnetic gap, the width of the magnetic gap other than the portion where the thickness is smaller than the thickness of the magnet bonding portion is tapered so as to increase in the upward direction. Because
The increase in the magnetic flux density in this portion is reduced, and a more uniform magnetic flux density distribution can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a half sectional view of a speaker having a diameter of 18 cm according to a first embodiment of the present invention. The speaker is magnetized in the thickness direction near the outer peripheral edge of the upper surface of a disc-shaped bottom plate 3 having an outer diameter φ95 and a thickness t = 8. Diameter φ100, inner diameter φ
A ring-shaped main magnet 2 having a thickness of t = 15 and an outer diameter of φ106, an inner diameter of φ49.1 manufactured by a forging method, a thickness t = 8 of a magnet bonding portion, and a magnetic gap are mounted on the main magnet. Opposite part width w = 2
0, an integrated bending ring-shaped top plate 1a having a thickness w = 4 at that portion is attached, and a bottom plate 3
A ring-shaped sub-magnet 4 having an outer diameter φ80, an inner diameter φ40, and a thickness t = 15, which is magnetized in a direction opposite to that of the main magnet 2, is mounted near an outer peripheral edge of the lower surface of the main magnet 2. A yoke cover 5 is attached so as to cover from the top plate 1a to the sub magnet 4. An aluminum die-cast frame 6 having a diameter of 18 cm is mounted on the upper surface of the top plate 1a. Further, the frame 6 is provided on a magnetic gap portion formed by a pole portion at the upper center of the top plate 1a and the bottom plate 3. There is a voice coil 7 supported by a suspension 8 having a fixed outer periphery. The winding width of the wire loop portion 7b of the voice coil 7 is w = 12, and the center of the winding width of the wire loop portion is aligned with the center of the magnetic gap facing width of the top plate 1a. Further, the upper surface thereof has a structure in which the outer periphery is fixed to the frame 6, the inner periphery is fixed to the voice coil 7, and the diaphragm 9 having the dust cap 10 with the outer diameter φ58 is attached to the center thereof.

FIG. 2 is a magnetic flux density distribution diagram of the magnetic gap according to the first embodiment. The basic configuration in the figure is the same as that in FIG. 8, and the magnitude of the magnetic flux density is shown by a curve B. As described above, the magnitude of the magnetic flux density within the width of the top plate 1a facing the magnetic gap is substantially uniform, but about 0.3700T in the part Y1a and about 0.3600T in the part Y2a in the figure.
And the magnetic flux density of the thin portion (Y2a) is small (about-
3%). In the portion of Y2a, the value decreases as going downward.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In this embodiment, the only difference from the first embodiment is the shape of the top plate 1b. That is, the portion of the top plate 1a facing the magnetic gap where the thickness is smaller than the thickness of the magnet bonding portion is tapered downward without changing the width of the magnetic gap. It is.

FIG. 4 shows a magnetic flux density distribution chart of the magnetic gap according to the second embodiment. The basic configuration in the figure is the same as that in FIG. 8, and the magnitude of the magnetic flux density is shown by a curve C. Thus, both Y1b and Y2b have the same value as about 0.3700T, and the uniformity of the magnetic flux density is improved.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In this embodiment, the only difference from the first embodiment is the shape of the top plate 1c. That is, in the portion of the top plate 1a facing the magnetic gap other than the portion where the thickness is smaller than the thickness of the magnet bonding portion, the magnetic gap is tapered so that the width of the magnetic gap increases in the upward direction. That is the point.

FIG. 6 shows a magnetic flux density distribution diagram of the magnetic gap according to the third embodiment. The basic configuration in the figure is the same as that in FIG. 8, and the magnitude of the magnetic flux density is shown by a curve D. Thus, both Y1c and Y2c have the same value as about 0.3600T, and the uniformity of the magnetic flux density is improved.

In each of the above-described embodiments, an external magnet type speaker has been described as an example. However, it goes without saying that an internal magnet type speaker may be used.

[0019]

As described above, according to the loudspeaker having the magnetic circuit according to the present invention, the width facing the magnetic gap is widened irrespective of the thickness of the top plate, so that the material cost can be greatly reduced. The length of the voice coil loop can be increased, and the moving range of the voice coil within the range of the uniform magnetic flux density distribution can be widened, so that a highly efficient and low distortion speaker can be constructed. It is of great industrial value.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a configuration of a speaker according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a magnetic flux density distribution of the speaker magnetic circuit in the first embodiment.

FIG. 3 is a half sectional view showing a configuration of a speaker according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a magnetic flux density distribution of the speaker magnetic circuit in the second embodiment.

FIG. 5 is a half sectional view showing a configuration of a speaker according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a magnetic flux density distribution of the speaker magnetic circuit in the third embodiment.

FIG. 7 is a half sectional view showing a configuration of a conventional speaker.

FIG. 8 is an explanatory diagram showing a magnetic flux density distribution of a conventional speaker magnetic circuit.

[Explanation of symbols]

 1a, 1b, 1c Top plate 2 Main magnet 3 Bottom plate 4 Sub magnet 5 Yoke cover 6 Frame 7 Voice coil 7b Voice coil wire loop 8 Suspension 9 Vibration plate 10 Dust cap

Claims (3)

(57) [Claims] 1. A gap facing a magnetic gap portion.
The width of the facing part is the
The thickness of the gap opposing portion is smaller than the thickness of the bonding portion.
In There integral bent shape, the top surface of the gap facing portion heaven than the top surface of the lamination unit
Equipped with a top plate that does not protrude in the plane direction
A voice coil having a magnetic circuit and a winding width smaller than the width of the gap opposing portion.
It is arranged in the magnetic gap portion and faces the gap over the vibration region of the voice coil.
Characterized in that the magnetic flux density generated in the part is substantially uniform
Speaker. 2. A gap facing a magnetic gap portion.
The width of the facing part is the
The thickness of the gap opposing portion is smaller than the thickness of the bonding portion.
In There integral bent shape, the top surface of the gap facing portion heaven than the top surface of the lamination unit
Without protruding in the plane direction, the thickness of the gap opposing portion becomes thinner toward the tip.
So that the magnet side has a substantially linear taper shape.
Has a magnetic circuit equipped with a top plate that Tsu, the voice coil of smaller winding width than the width of the gap facing portion
The spin head is disposed in the magnetic gap.
Oka. 3. A gap facing a magnetic gap portion.
The width of the facing part is the
The thickness of the gap opposing portion is smaller than the thickness of the bonding portion.
In There integral bent shape, the top surface of the gap facing portion heaven than the top surface of the lamination unit
The gap portion does not protrude in the plane direction, and the magnetic gap dimension of the gap portion approaches the top surface side
It becomes a substantially linear taper shape so that it becomes larger as
It has a magnetic circuit equipped with a top plate and a voice coil of smaller winding width than the width of the gap facing portion
The spin head is disposed in the magnetic gap.
Oka.