JP2002027591A - Magnetic circuit and loudspeaker using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic circuit to be used for a loudspeaker to be used for acoustic equipment and the loudspeaker using this magnetic circuit capable of improving the heat radiating effects of the magnetic circuit, and making the loudspeaker compact by using the magnetic circuit. SOLUTION: In this radial type magnetic circuit, a plurality of divided magnets 1 are magnetized in parallel to the thickness direction, and notched parts 4 are formed at the positions where the density of the magnetic fluxes of the magnets 1 is thin of a faced yoke 3 so that the aeration of a magnetic void 12 can be improved by the notched parts 4 for interrupting the magnetic efficiency, and that the increase of the temperature of the magnetic circuit can be suppressed. Therefore, it is possible to attain the miniaturization and high performance of the magnetic circuit and the speaker using the magnetic circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic circuit used for a speaker used for audio equipment and a speaker using the same.

[0002]

2. Description of the Related Art In recent years, with the space saving of audio equipment and the like, there is an increasing demand for smaller and lighter speakers mounted thereon. It is effective to reduce the size of the magnetic circuit to reduce the size and weight of the speaker.
-B-based magnets are often used.
In addition, as one means for increasing the efficiency, there is a magnetic circuit in which a magnet is formed in a ring shape and magnetized in a radial direction to form a magnetic gap on the inner circumferential surface or the outer circumferential surface of the magnet (hereinafter referred to as a radial magnetic circuit). Call).

[0003]

In a loudspeaker using a radial type magnetic circuit, a voice coil which is a heat source in a magnetic space is opposed to a magnet at a very short distance from the magnet. Heat is easily transmitted, and since the inside of the magnetic space is a narrow space, the cooling effect by ventilation with the outside air is small, so that the magnet is easily heated to a high temperature. Therefore, it is necessary to raise the starting temperature of the thermal demagnetization of the magnet and raise the operating point of the magnet. However, in order to increase the operating point, it is practical to increase the thickness of the magnet in the magnetizing direction, so that the volume of the magnet increases.

Further, in the radial magnetic circuit, in order to magnetize the magnet, a special magnetizing machine is required for magnetizing in the radial direction of the annular magnet, and the method itself is expensive in terms of the construction method. It had the following.

[0005]

According to a first aspect of the present invention, there is provided a magnet for magnetizing a plurality of divided magnets in parallel in a thickness direction, and opposing the magnet via an air gap. Notches are provided at a plurality of sparse positions of the magnetic flux density of the magnet of the yoke or the center pole to improve the ventilation of the magnetic gap and suppress the temperature rise of the magnet of the magnetic circuit by the notches. In addition, since the notch is provided at a position where the magnetic flux density of the magnet is sparse, it is possible to provide a compact and highly efficient magnetic circuit without impairing the magnetic efficiency of the magnetic circuit.

According to a second aspect of the present invention, a magnet is mounted on a center pole, a notch is provided on a peripheral surface of a yoke facing between adjacent magnets, and the magnets are mounted in parallel in a thickness direction. 2. The magnetic circuit according to claim 1, wherein the position of the notch in the yoke can be set very easily to a position facing between the adjacent magnets, so that productivity can be improved and magnetization of the magnet can be performed. Unlike a conventional ring-shaped magnet, the magnet is arc-shaped, so that a general magnetizing machine can be used.

According to a third aspect of the present invention, the magnet is mounted on the yoke, the notch is provided on the peripheral surface of the center pole facing the magnet, and the magnet is magnetized in parallel in the thickness direction. The magnetic circuit according to claim 1, wherein the position of the notch at the center pole can be set very easily to a position facing the magnet, as in claim 2, thereby improving productivity and improving the productivity of the magnet. Since the magnetization is also in the form of an arc unlike the conventional ring-shaped magnet, a general magnetizing machine can be used.

According to a fourth aspect of the present invention, there is provided a speaker using the magnetic circuit according to the first, second, or third aspect, which enables the speaker to be reduced in size and performance. is there.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a speaker using a magnetic circuit according to the present invention will be described below with reference to FIGS.

FIG. 1A is a top view of an embodiment of a magnetic circuit according to the present invention, FIG. 1B is a sectional view taken along the line AOB, and FIG. FIG. 3A is a side cross-sectional view of the used speaker, FIG. 3A is a top view of a developed example of the magnetic circuit, FIG. 3B is a cross-sectional view of the same AOB line, and FIG.
FIG. 2 is a side sectional view of a speaker using the magnetic circuit.

According to FIG. 1, reference numeral 1 denotes a plurality of magnets which are magnetized in the horizontal direction and are connected to the periphery of the upper part of the center pole 2 of the yoke 3. Thus, a magnetic gap 12 is formed.

Reference numeral 4 denotes a notch provided on the inner periphery of the yoke 3, which is provided at a position facing between adjacent magnets of the plurality of magnets 1. The arrow on the magnet 1 indicates the magnetization direction (magnetization direction).

Reference numeral 5 denotes a voice coil fitted in the magnetic gap 12, and reference numeral 6 denotes a damper whose inner periphery is coupled to the voice coil 5 and whose outer periphery is coupled to the frame 11 which is coupled to the yoke 3. Reference numerals 8 denote diaphragms having an edge portion on the outer periphery, the inner periphery being coupled to the voice coil 5 and the outer periphery being coupled to the frame 11, respectively. Reference numeral 10 denotes a dust cap coupled to the diaphragm 8 so as to cover the voice coil 5.

As shown by the arrow in FIG. 1A, the magnetizing direction of the magnet 1 is parallel to the thickness direction while the conventional ring-shaped magnet is magnetized in the center direction (radial direction). Is going.

Next, the detailed configuration of the embodiment will be described together with the operation.

The magnetic flux emitted from the magnet 1 passes through a magnetic gap 12 formed by the outer peripheral surface of the magnet 1 and the inner peripheral surface of the yoke 3, and further passes through the inside of the yoke 3.
A magnetic path that returns to the magnet 1 via the center pole 2 is formed. Since each of the magnets 1 is magnetized in a direction parallel to the thickness direction, the amount of the magnetic flux flowing in the magnetizing direction decreases on the side of the magnetic gap 12 adjacent to the magnet 1. Furthermore, the distance between the outer peripheral surface of the adjacent portion of the magnet 1 and the inner peripheral surface of the yoke 3 is increased by the cutout portion 4 of the yoke 3 provided opposite to each adjacent portion of the magnet 1. The magnetic resistance in the magnetic gap 12 at the site increases. Therefore,
The magnetic flux concentrates on a portion where the magnetic resistance is small between the magnet 1 and the inner peripheral surface of the yoke 3 where the notch 4 is not provided, so that the magnetic flux can be efficiently collected from the magnet 1 into the magnetic gap 12.

As described above, since the magnets which are magnetized in the horizontal direction (parallel to the thickness direction) are used, a general magnetizer can be used as the magnetizer, not only for the conventional ring-shaped magnet. In addition, since the magnetization direction is made parallel to the thickness direction, in the present embodiment, the magnetic efficiency is reduced as described later by setting the vicinity of the notch 4 provided in the yoke 3 to a position having a low magnetic flux density. The heat dissipation effect of the magnetic circuit is improved without any problem.

The positional relationship between the notch 4 provided in the yoke 3 and the magnet 1 is set so that the position can be set very easily by visual recognition that the notch 4 is provided at an opposing position between the adjacent magnets 1. Has become.

Next, a case where the magnetic circuit of the present invention is applied to a general speaker will be described. The voice coil 5 suspended in the magnetic gap 12 formed by the outer peripheral surface of the magnet 1 and the inner peripheral surface of the yoke 3 becomes a heat source when driven. The heat of the voice coil 5 is transmitted to the voice coil bobbin 5 a joined to the inner peripheral surface of the voice coil 5, and further transmitted through the air layer sandwiched between the inner peripheral surface of the voice coil bobbin 5 a and the outer peripheral surface of the magnet 1. 1 is transmitted. The temperature of the magnet 1 rises through this heat transfer path.

On the other hand, the internal space of the dust cap 10 formed by the lower surface of the dust cap 10, the inner peripheral surface of the voice coil bobbin 5a, and the upper surfaces of the magnet 1 and the center pole 2, and the outer peripheral surface of the magnet 1 and the voice coil bobbin 5a A gap sandwiched between the inner peripheral surfaces, a magnetic circuit internal space formed by the lower surface of the magnet 1, the outer peripheral surface of the center pole 2, the upper surface of the bottom of the yoke 3 and the inner peripheral surface, and the outer peripheral surface of the voice coil 5 , A gap between the inner surface of the yoke 3, a damper internal space formed by the lower surface of the damper 6, the outer peripheral surface of the voice coil bobbin 5 a, and the upper surface of the yoke 3, a highly permeable damper 6 and a frame In addition to ventilating the outside air through the 11 ventilation windows, the magnet 1
The voice coil 5, which is a heat source, is cooled by ventilation.

At this time, compared to the conventional radial type magnetic circuit, the notch 4 of the yoke 3 facilitates ventilation so that the cooling effect is enhanced. Therefore, since the temperature rise of the magnet 1 is suppressed as compared with the conventional radial magnetic circuit, the operating point can be set lower. That is, the thickness of the magnet 1 can be reduced so that the cost of the magnet can be reduced and the size and weight of the magnetic circuit can be reduced.

FIG. 3A shows a development example of the above embodiment.
4 (b) to FIG. 4, the same parts as those of the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The difference from the above embodiment is the configuration of the magnetic circuit. Reference numeral 1a denotes a plurality of magnets coupled to the inner periphery of the yoke 3a and magnetized in a direction parallel to the thickness direction.
A magnetic gap 12 is formed between the magnet 1 and the inner circumference of the center pole 2.

A notch 4a is provided on the outer periphery of the center pole 2, and is provided at a position facing the plurality of magnets 1a.

The arrow on the magnet 1a indicates the magnetization direction (magnetization direction).

In the magnetic circuit configured as described above, since the magnetization direction of the magnet 1a is parallel to the thickness direction, the position of the center pole 2 facing the magnet 1a is different from that of the above-described embodiment. By providing the notch 4a at this position, the heat dissipation effect of the magnetic circuit is improved without lowering the magnetic efficiency.

The notch 4 provided in the center pole 2
The positional relationship between a and the magnet 1a can be set very easily by visual recognition that a notch 4a is provided at a position facing the magnet 1a.

FIG. 4 is a side sectional view of a speaker using this developed example, but the effect of using the magnetic circuit of the configuration and the developed example is the same as that of the speaker of the above-described embodiment of FIG. Description is omitted because there is.

As described above, the magnetic circuit and the loudspeaker using this magnetic circuit have been described according to the embodiment and the development example, and the magnets 1 and 1a are described as being magnetized in parallel in the thickness direction. It is not necessary to limit the magnet to a direction parallel to the thickness direction.By controlling the magnetizing direction of the magnet, a sparse portion of the magnetic flux density is formed on the yoke or center pole side where no magnet is mounted, and this sparse portion is formed. By forming a notch in the magnetic circuit, the ventilation of the magnetic air gap is improved without lowering the magnetic efficiency of the magnetic circuit, thereby improving the heat radiation effect, making the magnetic circuit smaller and lighter, and the speaker using the same smaller and lighter. The present invention is also possible and falls within the scope of the present invention.

In the above embodiment, the number of magnets 1 has been described as eight. However, the number is not limited to eight, and may be odd or even.

Although the number of the cutouts 4 or 4a has been described as being the same as the number of the magnets 1, the number is not necessarily the same. Although the shape has been illustrated as a semicircle, the shape is not limited to this, and may be, for example, triangular or completely slit. Further, the depth of the notch 4 may penetrate the entire magnetic circuit, or may extend to any position in the middle.

Further, the shape of the magnet 1 is illustrated in an arc shape (tile shape, bow shape), but it is not limited to this, and may be, for example, a semi-cylindrical shape.

Further, regarding the shape of the entire magnetic circuit, the magnetic circuit having one annular magnet and one magnetic gap has been illustrated and described. However, the present invention is not limited thereto. There may be more than one.

[0034]

As described above, the present invention can improve the heat radiation effect of the radially magnetized magnetic circuit and contribute to the reduction in size and weight of the magnetic circuit, and the size and weight of a speaker using the same. It can contribute to the development.

[Brief description of the drawings]

FIG. 1A is a top view of an embodiment of a magnetic circuit according to the present invention. FIG.

FIG. 2 is a side sectional view of a speaker using the magnetic circuit.

FIG. 3A is a top view of a development example of the magnetic circuit, and FIG.

FIG. 4 is a side sectional view of a speaker using the magnetic circuit.

[Explanation of symbols]

 1, 1a magnet 2 center pole 3, 3a yoke 4, 4a notch 5 voice coil 6 damper 8 diaphragm 11 frame 12 magnetic gap

Claims (4)

[Claims] At least a center pole, a yoke arranged on the outer periphery of the center pole, and a plurality of magnets dividedly mounted on the center pole or the yoke between the center pole and the yoke in a circumferential direction. A magnetic circuit comprising: a notch provided at a plurality of sparse positions of the magnetic flux density of the magnet of the yoke or the center pole facing the magnet via a gap. 2. A magnet is mounted on a center pole, a notch is provided on a peripheral surface of the yoke facing between adjacent magnets, and the magnets are magnetized in parallel in a thickness direction. 2. The magnetic circuit according to 1. 3. The magnetic device according to claim 1, wherein the magnet is mounted on the yoke, the notch is provided on the peripheral surface of the center pole facing the magnet, and the magnet is magnetized in parallel in the thickness direction. circuit. 4. The method according to claim 1, 2 or 3.
, A frame coupled to the magnetic circuit, and a diaphragm having an outer periphery coupled to the frame and an inner periphery coupled to a voice coil fitted into the magnetic gap of the magnetic circuit. Speaker.