JPH0543697U - Magnetic circuit for speaker - Google Patents

Abstract

(57) [Summary] [Purpose] A secondary magnet is used to reduce the leakage flux and improve the magnetic flux density in the magnetic gap. [Structure] In an inner magnet type magnetic circuit in which a right circular ring-shaped main magnet is fitted between a lower outer surface of a center pole and a lower inner surface of a cylindrical yoke, the inner magnetic surface of the upper portion of the cylindrical yoke is The sub-magnet is inserted and held in the outer circumference of the annular sub-magnet to form a magnetic gap between the pole and the tip of the pole, and the sub-magnet is inserted in series in the magnetic path direction of the main magnet and attached in the radial direction. The magnetic circuit for the speaker is magnetized in the opposite direction of the main magnet.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic circuit for a speaker, in which the performance of a main magnet used for an inner magnet type is brought out to a high degree and a magnetic flux leaking to the surroundings is reduced by a sub magnet.

[0002]

[Prior Art]

 Conventionally, the magnetic circuit (5 ') of this type of speaker (11') has a cylindrical shape in the recess (2g ') provided on the inner bottom surface of the lower plate (2e') as shown in FIG. For example, place an alnico magnet (3 '), fix the center pole (1') on it, and insert the center pole (2d ') in the center magnetic hole (2d') of the upper plate (2c '). 1 '), let the tip magnetic pole part (1a') look out, and lower the side surface part (2b ') of the cylindrical yoke side surface part (2a') to the side edge part of the lower plate (2e ') ( The so-called inner magnet type magnetic circuit structure was mainly formed by fitting and fixing the inner surface of 2f ') to form an annular magnetic gap. Then, the voice coil (8 ') is supported by the damper (9') in the magnetic gap of the magnetic circuit (5 '), and the outer periphery of the tip thereof is attached to the frame (7') on the diaphragm (10 '). ) Was attached, and it was assembled as a speaker (11 ').

[0003]

[Problems to be solved by the device]

 Therefore, in this type of conventional inner magnet type magnetic circuit (5 ′), as shown in FIG. 8, the magnetic gap portion is the most magnetic in the entire magnetic path of the magnetic circuit (5 ′). Since the resistance is large, the flow of the magnetic force lines mostly leaks out of the magnetic air gap and leaks, and the ratio of the magnetic flux passing through the magnetic air gap, which is the source of the driving force of the voice coil, is small. There was a problem that a good speaker could not be obtained.

Therefore, in order to solve the problem that the conventional inner magnet type magnetic circuit (5 ′) has, the first device of the present invention uses a conventional alnico as the main magnet (3). By using a magnet and using a similar alnico magnet as a sub magnet (4) in part of the magnetic path, the main magnet (3) demonstrates the performance of the magnetic circuit (5) and the sub magnet (4). By utilizing the magnetomotive force of the magnet, the leakage magnetism that leaks to the outside of the magnetic space (6) is reduced, the use efficiency of both the main and sub magnets (3), (4) is increased, and the space factor of the magnet is improved. The magnetic flux density of the magnetic air gap (6) is dramatically improved for the purpose of providing a magnetic circuit (5) suitable for a small, powerful and highly efficient speaker. According to the second invention, another magnetized bottom magnet (7) is fixed to the lower surface of the center pole (1) of the speaker having the magnetic circuits (5a) and (50a) of the first invention to further reduce the leakage flux. This is the magnetic circuit (5b) for the speaker, which has been reduced. In the third invention, the upper surfaces of the auxiliary magnets (4) of the magnetic circuits (5a), (50a), (5b) having the structures of the first and second inventions are arranged so that the upper surface (1a) of the center pole (1) is At least the magnetic circuit (5c) placed high.

[0005]

[Means for Solving the Problems]

 The structure of the present invention for achieving the above object will be described with reference to FIGS. 1 to 4 corresponding to the embodiment. The first device of the present invention, as shown in FIGS. 1 and 2, is a center pole (1). In the inner magnetic type magnetic circuit in which the main magnet (3) with a circular ring shape is fitted between the lower outer surface (1b) of the and the lower inner surface (2b) of the cylindrical yoke (2), the cylindrical yoke ( On the inner side surface (2h) of the upper part (2a) of (2), the outer peripheral part of the sub-circular magnet (4) is fitted and held, and the tip parts (1a) of the poles (1), (10) are , (10a), a magnetic air gap (6) is formed, and the auxiliary magnet (4) inserted and installed in series in the magnetic path direction of the main magnet (3) is connected to the main magnet (3) in the radial direction. Magnetic circuits for speakers (5a) and (50a) magnetized in the opposite direction to the magnetization direction.

The second invention is, as shown in FIG. 3, between the lower outer surface (1b) of the center pole (1) and the lower inner surface (2b) of the cylindrical yoke (2), a circular ring shape. In the inner magnet type magnetic circuit in which the main magnet (3) of (1) is inserted, the outer periphery of the sub-circular magnet (4) is inserted in the inner surface (2h) of the upper part (2a) of the cylindrical yoke (2). Hold it in place and form a magnetic gap (6) between it and the tip (1a) of the center pole (1), and insert and insert it in series in the magnetic path direction of the main magnet (3). ) Is a magnetic circuit for a speaker magnetized in the radial direction in the direction opposite to the magnetization direction of the main magnet (3), and another bottom magnet (7) is fixed to the bottom surface of the center pole (1) and magnetized. This is the magnetic circuit (5b) for the speaker.

In the third invention, as shown in FIG. 4, the upper surface of the cylindrical yoke (2) is flush with the upper surface of the sub-magnet (4) of the first and second inventions. The speaker magnetic circuit (5c) is positioned higher than the upper surface (1a) of the center pole (1) including the upper surface (2a) by at least the difference (D).

[0008]

[Action]

 Since each of the present invention has the above-mentioned structure, as shown in FIGS. 1 to 4, the main magnet is inserted in series in the magnetic path direction of the main magnetic circuit using the annular alnico magnet. By using the magnetomotive force of the sub-magnet (4) magnetized in the direction opposite to the road direction and in the radial direction, the leakage magnetism that leaks to the outside of the magnetic air gap (6) is reduced and the magnetic flux inside the magnetic air gap (6) is reduced. Can be concentrated. In the second invention, the leakage flux of the main magnet (3) is further reduced by the magnetomotive force of another bottom magnet (7) on the lower surface of the center pole (1) to reduce the effective magnetic flux density in the magnetic air gap (6). It acts to improve the degree. In the third invention, the magnetic flux concentrated at the corners (1c) and (4c) of the magnetic poles is pulled into the magnetic air gap (6) by providing a height difference, so that the leakage magnetic flux is reduced and the magnetic space ( 6) It works to improve the effective magnetic flux density.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are views showing one embodiment of the first invention of the present invention, and are vertical cross-sectional views showing the vertical cross-sectional views thereof. The first invention shown in FIG. 1 is a main circular ring between a lower outer surface (1b) of a cylindrical center pole (1) and a lower inner surface (2b) of a cylindrical yoke (2). It is an inner magnet type magnetic circuit in which a magnet (3) is inserted. Then, the outer circumference of the sub-circular magnet (4) is fitted and held on the inner surface (2h) of the upper part (2a) of the cylindrical yoke (2), and the poles (1), (10) A magnetic air gap (6) is formed between the tips (1a) and (10a) of the main magnet (3), and the auxiliary magnet (4) is inserted and installed in series in the magnetic path direction of the main magnet (3). This is a speaker magnetic circuit (5a) magnetized in the direction opposite to the magnetizing direction of the magnet (3).

The embodiment of the first invention shown in FIG. 2 is a magnetic circuit in which a center hole (10c) is formed in the center of the center pole (10) instead of the center pole (1) of the magnetic circuit (5a) of FIG. The circuit (50a) is the same as the magnetic circuit (5a) of FIG. 1 in the other structure, and the operational effect is the same as that of the magnetic circuit (5a) of FIG.

In the embodiment of the second invention, as shown in FIG. 3, the lower outer side surface (1b) of the cylindrical center pole (1) and the lower inner side surface (2b) of the cylindrical yoke (2) are formed. In the inner magnetic type magnetic circuit in which the main magnet (3) in the shape of a circular ring is inserted between the inner side surface (2h) of the upper part (2a) of the cylindrical yoke (2), the auxiliary magnet of the circular ring ( 4) Insert and hold the outer peripheral part of the center pole (1) to form a magnetic gap (6) between the center pole (1) and the tip (1a) of the center pole (1). In the magnetic circuit for the loudspeaker in which the sub-magnet (4) inserted into and mounted in the radial direction is magnetized in the direction opposite to the magnetization direction of the main magnet (3), another flat plate-shaped magnet is attached to the lower surface of the center pole (1). A magnetic circuit (5b) for a speaker, in which a bottom magnet (7) magnetized in the thickness direction of a magnet (7) is magnetized in the magnetization direction of the main magnet (3).

The magnetic circuit (5b) of FIG. 3 has the magnetic structure of any one of the first and second inventions shown in FIG. 1, 2 or 3 due to the magnetomotive force of the bottom magnet (7). This has the effect of reducing the leakage magnetic flux in the back direction of the magnetic circuit (5b) as compared with the circuits (5a) and (50a).

The magnetic circuit (5c) of the third invention shown in FIG. 4 has a structure obtained by modifying the magnetic circuits (5a), (50a), (5b) of the first invention and the second invention, respectively. The upper surface of the center pole (1) (including the upper surface of the upper part (2a) of the cylindrical yoke (2) flush with the sub magnets (4) of the first and second inventions) It is the magnetic circuit for the speaker (5c) which is positioned at least (D) higher than 1a). That is, the upper surface of the upper plate (2c) in which the sub magnet (4) is fitted and held is at least different from the upper surface (1a) of the center pole (1) including the upper surface of the sub magnet (4) ( D) The magnetic circuit (5c) for the speaker, which is positioned higher than the above. Here, the relational expression of the difference D> 0 holds. In the magnetic circuit (5c) of the third invention, in the magnetic air gap (6), the angle of the center pole (1) on which the magnetic flux is concentrated is lower by (D) than the upper surface of the counter magnet (4) of the opposite pole. The magnetic flux (6) is located at a certain level, and the upper part of the magnetic air gap (6) where the magnetic flux concentrates is drawn into the magnetic air gap (6), which causes the number of magnetic fluxes leaked to the outside. It has decreased.

Although the embodiments considered to be typical of the present invention have been described above, the present invention is not necessarily limited to only the structures of these embodiments, and has the above-mentioned constitutional requirements referred to in the present invention, and The present invention can be carried out with appropriate modifications within the scope of achieving the object of the present invention and having the following effects.

[0015]

[Effect of the device]

 As is apparent from the above description, the present invention has such a structure, and therefore, for example, a conventional alnico magnet is used for the main magnet (3) and another auxiliary magnet of the same shape ( By using it as a part of the main magnetic path as 4), the magnetic circuit performance of the main magnet (3) and the magnetomotive force of the auxiliary magnet (4) are utilized to create a magnetic field outside the magnetic air gap (6). The magnetic flux density in the magnetic air gap is dramatically increased with the aim of improving the space factor of the magnet by increasing the efficiency of use of both the main and sub magnets (3) and (4) by reducing the leakage magnetic flux that leaks. The magnetic circuit (5) will be improved to be compact, powerful and suitable for high efficiency speakers. Further, in the second invention, the leakage flux of the main magnet (3) is reduced by the magnetomotive force of another bottom magnet (7) on the lower surface of the center pole (1), and the effective magnetic flux in the magnetic air gap (6) is reduced. The density can be improved. In the third invention, the magnetic flux concentrated in the corners (1c) and (4c) of the magnetic poles is pulled into the magnetic air gap (6) by providing a height difference, thereby reducing the leakage magnetic flux and reducing the magnetic space ( The effect that the effective magnetic flux density in 6) can be improved can be revealed. The main dimensions of the magnetic circuit of the conventional example and the present invention, the maximum magnetic flux density of the air gap, and the maximum leakage magnetic flux density are compared and listed in Table 1.

[0016]

[Table 1]

A comparison of the real numbers of the leakage magnetic flux measured along the direction parallel to the axis of the magnetic circuit in the vicinity of the side surface of the magnetic circuit between the conventional example and the present invention is as shown in FIGS. The horizontal axis shows the position 0 mm ahead of the front surface of the magnetic circuit as the origin 0, and the distance from the origin is taken. The vertical axis shows the absolute value of the magnetic flux density from that point. The measurement position is as shown in FIG. As can be seen from the above, the embodiment of the present invention has less leakage flux of 63% to 75% than the conventional example, and the effect is exhibited by effectively acting. That is, there is a large difference in the leakage magnetic flux between the conventional example shown in FIG. From this, the difference is the largest at the measurement point 4 cm from the origin O outside the magnetic circuit.

FIG. 7 is a comparison of the magnetic flux densities generated in the magnetic gap of the conventional example and the embodiment of the present invention. The horizontal axis represents the distance from the upper end (0) of the magnetic gap, and the vertical axis represents the magnetic flux density. Represents the absolute value of. As can be seen from the figure, near the center of the magnetic gap, the first device is 9,800 gauss, the second device is 9,900 gauss, and the conventional example is 8,900 gauss. The embodiment improves the conventional example by about 11%. There is. As shown in FIG. 4, a third invention is a modification of the speaker magnetic circuit according to claims 1 and 2, wherein the sub-magnet (4) is fitted and held in the upper plate (2c). The upper surface of the center pole (1) () includes the upper surface of the sub-magnet (4) and is positioned higher than the upper surface (1a) of the center pole (1) by at least a difference (D). The location where the magnetic flux is most concentrated in the corner of 1a) faces the middle part of the magnetic air gap (6) of the sub-magnet (4), so the magnetic flux is drawn downward and the leakage rate decreases, The effect of increasing the magnetic flux density of the void has the effect of further improving it.

[Submission date] January 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

In the embodiment of the second invention, as shown in FIG. 3, a lower outer side surface (1b) of a cylindrical center pole (1) and a lower inner side surface (2b) of a cylindrical yoke (2) are provided. An inner magnet type magnetic circuit in which a main magnet (3) in the form of a right circular ring is fitted between the inner side surface (2h) of the upper part (2a) of the cylindrical yoke (2), and a secondary circular ring-shaped auxiliary magnet. The outer peripheral portion of the magnet (4) is fitted and held, and a magnetic gap (6) is formed between the center pole (1) and the tip portion (1a) of the main pole (3). In a magnetic circuit for a speaker in which a sub-magnet (4) inserted and mounted in series in a direction is magnetized in the radial direction in a direction opposite to the magnetization direction of the main magnet (3), another flat plate is provided on the lower surface of the center pole (1). The bottom magnet (7) magnetized in the thickness direction was magnetized in the thickness direction in a direction coinciding with the direction of the magnetic flux formed by the main magnet (3). The speaker magnetic circuit (5b).

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The magnetic circuit (5c) of the third invention shown in FIG. 4 has a modified structure of the magnetic circuits (5a), (50a), (5b) of the first invention and the second invention, respectively. The upper surface of the center pole (1) (including the upper surface of the upper portion (2a) of the cylindrical yoke (2) flush with the sub magnet (4) of the first and second inventions). The magnetic circuit for a speaker (5c) is positioned at least (D) higher than 1a). That is, the upper surface of the cylindrical yoke (2) in which the sub magnet (4) is fitted and held is more than the center pole (1) upper surface (1a) including the upper surface of the sub magnet (4). The speaker magnetic circuit (5c) is structured to be positioned at least higher than the difference (D). Here, the relational expression of the difference D> 0 holds. In the magnetic circuit (5c) of the third invention, the angle of the center pole (1) in which the magnetic flux is concentrated is lower than the upper surface of the counter magnet (4) by (D) in the magnetic gap (6). The magnetic flux (6) is located at a certain position, and an upper part of the magnetic air gap (6) in which the magnetic flux concentrates is drawn into the magnetic air gap (6) to generate the magnetic flux. It has decreased.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

FIG. 7 is a comparison of the magnetic flux density generated in the magnetic gap of the conventional example and the embodiment of the present invention, in which the horizontal axis represents the distance from the magnetic gap upper end (0) and the vertical axis represents the magnetic flux density. Represents the absolute value of. As can be seen, in the vicinity of the center of the magnetic gap, the first device has 9,800 gauss, the second device has 9,900 gauss, and the conventional device has 8,900 gauss. % Has improved. As shown in FIG. 4, a third invention is a modification of the speaker magnetic circuit according to any one of claims 1 and 2, wherein a cylindrical yoke ( in which the sub magnet (4) is fitted and retained). The upper surface of the center pole (1) ( 2) including the upper surface of the auxiliary magnet (4) is positioned higher than the upper surface (1a) of the center pole (1) by at least a difference (D). 1a) The most concentrated magnetic flux at the corners faces the mid-abdomen of the magnetic air gap (6) of the sub-magnet (4), so the magnetic flux is drawn downward and its leakage rate decreases, resulting in a magnetic air gap. The effect of increasing the magnetic flux density is further improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a magnetic circuit according to an embodiment of the first invention.

2 is a longitudinal sectional view of a modification of the magnetic circuit shown in FIG.

FIG. 3 is a longitudinal sectional view of a magnetic circuit according to an embodiment of the second invention.

FIG. 4 is a vertical sectional view of a magnetic circuit according to an embodiment of the third invention.

FIG. 5 is a comparison diagram of side leakage magnetic flux of a conventional example and a magnetic circuit of an example of the present invention.

FIG. 6 is a diagram showing positions of measurement points in FIG.

FIG. 7 is a comparison diagram of the magnetic flux densities of the magnetic gaps of the magnetic circuit of the conventional example and the example of the present invention.

FIG. 8 is a vertical cross-sectional view of a speaker using a conventional magnetic circuit.

[Explanation of symbols]

 (1) Center pole (1a) Center pole tip (1b) Center pole lower inner surface (2) Cylindrical yoke (2a) Cylindrical yoke upper (2b) Cylindrical yoke lower inner surface (2c) Upper plate (2d) Upper end (2h) Inner surface of upper part of cylindrical yoke (3) Main magnet (4) Sub magnet (5a) Magnetic circuit (5b) Magnetic circuit (5c) Magnetic circuit (6) Magnetic air gap (7) Bottom magnet (10) Center Pole (10a) Center pole tip (50a) Magnetic circuit (D) Difference

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[Procedure amendment]

[Submission date] January 24, 1992

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[1] Center pole (1a) Center pole tip (1b) Center pole lower inner surface (2) Cylindrical yoke (2a) Cylindrical yoke upper (2b) Cylindrical yoke lower inner surface (2d) Upper end (2h) Inner surface of upper part of cylindrical yoke (3) Main magnet (4) Sub magnet (5a) Magnetic circuit (5b) Magnetic circuit (5c) Magnetic circuit (6) Magnetic air gap (7) Bottom magnet (10) Center Pole (10a) Center pole tip (50a) Magnetic circuit (D) Difference

Claims (3)

[Scope of utility model registration request] 1. A lower outer surface (1b) of the center pole (1),
In an inner magnet type magnetic circuit in which a right circular ring-shaped main magnet (3) is fitted between the inner surface (2b) of the lower part of the cylindrical yoke (2) and the inner part (2a) of the upper part (2a) of the cylindrical yoke (2). On the side surface (2h), fit the outer periphery of the auxiliary magnet (4) in the form of a right circular ring and hold it,
A magnetic air gap (6) is formed between the tips (1a) and (10a) of (1) and (10), and the auxiliary magnet (4) is inserted and installed in series in the magnetic path direction of the main magnet (3). ) Is magnetized in the direction opposite to the magnetization direction of the main magnet (3) in the radial direction. 2. A lower outer surface (1b) of the center pole (1),
In an inner magnet type magnetic circuit in which a right circular ring-shaped main magnet (3) is fitted between the inner surface (2b) of the lower part of the cylindrical yoke (2) and the inner part (2a) of the upper part (2a) of the cylindrical yoke (2). On the side surface (2h), the outer circumference of the auxiliary magnet (4) having a right circular ring shape is fitted and held, and a magnetic gap (6) is formed between the center pole (1) and the tip (1a). The auxiliary magnet (4) inserted in series in the magnetic path direction of the main magnet (3),
A magnetic circuit for a speaker magnetized in the direction opposite to the magnetizing direction of the main magnet (3) in the radial direction, in which another bottom magnet (7) is fixed to the bottom surface of the center pole (1) and magnetized for the speaker. circuit. 3. The upper surface of the sub-magnet (4) including the upper surface of the upper part (2a) of the cylindrical yoke (2) flush with the sub-magnet (4),
The speaker magnetic circuit according to claim 1 or 2, wherein the center pole (1) is positioned higher than the upper surface (1a) by at least a difference (D) or more.