CN108012225B

CN108012225B - Magnetic circuit structure of belt type loudspeaker

Info

Publication number: CN108012225B
Application number: CN201711191714.5A
Authority: CN
Inventors: 何永斌
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-11-24
Filing date: 2017-11-24
Publication date: 2020-11-17
Anticipated expiration: 2037-11-24
Also published as: CN108012225A

Abstract

The invention discloses a magnetic circuit structure of a belt type loudspeaker, which belongs to the technical field of electroacoustic, and comprises a central magnetic pole with a corner cutting structure at the front end and outer magnetic poles symmetrically arranged at two sides of the central magnetic pole, wherein the end surfaces of the two outer magnetic poles are parallel and opposite to the tangent plane at the front end of the central magnetic pole and form two magnetic gaps forming an included angle beta in the width direction, the value range of the included angle beta is more than or equal to 0 degree and less than 180 degrees, and loudspeaker diaphragms are arranged in the magnetic gaps. The magnetic circuit structure has higher magnetic field utilization rate and more uniform magnetic field distribution, so that the sound distortion degree of the diaphragm is low, and meanwhile, the magnetic circuit structure has better off-axis response effect.

Description

Magnetic circuit structure of belt type loudspeaker

Technical Field

The invention relates to a belt type loudspeaker which is one of electric loudspeakers in sound equipment, belongs to the technical field of electroacoustic, and particularly relates to a magnetic circuit structure in the belt type loudspeaker.

Background

The band type loudspeaker diaphragm is light and large in vibration area, and energy accumulation hardly exists in the vibration sounding process, so that the band type loudspeaker diaphragm has very excellent transient response; the electrified vibrating diaphragm is subjected to overall driving, segmentation and vibration in a magnetic field and has small self inductance and excellent high-frequency response, so that the electrified vibrating diaphragm is often used as a high-pitch loudspeaker; the narrow-band diaphragm is similar to a columnar sound field generated by a linear sounding body, so that the influence of ground and ceiling reflection is reduced, and the narrow-band diaphragm has excellent off-axis response.

A magnetic circuit structure of a general band-type speaker is shown in fig. 1, a thin-band conductive diaphragm is disposed between magnetic gaps of two magnetic poles, U-shaped magnetizers are disposed outside the two magnetic poles, and the diaphragm will vibrate under the driving of electromagnetic force after being energized with current.

Chinese patent CN 2614409Y discloses a magnetic circuit structure of a ribbon speaker, which is provided with ribbon metal sound films on both sides of an inner polar plate, and because the size of the restricted inner polar plate (too narrow for design, because it is thin and easy to be magnetically saturated and cause magnetic field non-uniformity), two sound films are far apart, so the two sound films have larger transverse equivalent distance, and therefore the phase interference of the two sound films is larger in off-axis response, and the off-axis response effect is worse.

Disclosure of Invention

The invention aims to provide a magnetic circuit structure of a belt type loudspeaker, which has high magnetic field utilization rate, low sound distortion degree of a diaphragm and good off-axis response effect.

Therefore, the invention provides the following technical scheme:

the invention provides a magnetic circuit structure of a belt type loudspeaker, which comprises a central magnetic pole with a corner cut structure at the front end and outer magnetic poles symmetrically arranged at two sides of the central magnetic pole, wherein two magnetic gaps forming an included angle beta in the width direction are formed between the end surfaces of the two outer magnetic poles and the front end of the central magnetic pole, the value range of the included angle beta is not less than 0 degree and not more than 180 degrees, and loudspeaker diaphragms are arranged in the magnetic gaps.

Preferably, the magnetic circuit structure further includes a permanent magnet and a rear magnetic conductive plate serially stacked on the rear end face of the central magnetic pole, two side magnetic conductive plates are further disposed between the rear magnetic conductive plate and the outer magnetic pole and symmetrically disposed on two sides of the central magnetic pole, and the permanent magnet forms two symmetrical closed magnetic circuits through the central magnetic pole, the two magnetic gaps, the two outer magnetic poles, the magnetic conductive plates on two sides, and the rear magnetic conductive plate.

Preferably, the magnetic circuit structure further includes a rear magnetic conductive plate closely attached to the rear end face of the central magnetic pole, and two permanent magnets clamped between the rear magnetic conductive plate and the outer magnetic pole and symmetrically arranged at two sides of the central magnetic pole, and the two permanent magnets form two symmetrical closed magnetic circuits through the rear magnetic conductive plate, the central magnetic pole, the two magnetic gaps, and the two outer magnetic poles.

Preferably, the section of the central magnetic pole has a boss structure relative to the magnetic gap portion.

As the optimization of the scheme of the invention, the included angle beta is 90 degrees, and the two vibrating diaphragms are mutually vertical.

As the optimization of the scheme of the invention, the included angle beta is 0 degree, and the two vibrating diaphragms are parallel and opposite.

As the optimization of the scheme of the invention, the rear magnetic conduction plate and the magnetic conduction plates at the two sides can be integrally processed into a U-shaped component.

As the optimization of the invention to the above scheme, the rear magnetic conductive plate and the central magnetic pole can be integrally processed into a T-shaped component.

The invention has the beneficial effects that: compared with a single magnetic gap magnetic circuit, the magnetic circuit structure of the belt type loudspeaker has the advantages that the single width of the magnetic gap of the magnetic circuit is narrower under the same vibration area, so that a magnetic field in the magnetic gap is more uniform, and the sound distortion is lower; the magnetic circuit has higher magnetic field utilization rate and very small magnetic flux leakage. Meanwhile, the two vibrating diaphragms form an included angle beta to radiate sound waves in different directions, the off-axis response effect is better, the problem of poor off-axis response effect of the vibrating diaphragms in the prior art due to large transverse equivalent distance is solved better by using the included angle beta formed by the two vibrating diaphragms, the transverse equivalent distance of the vibrating diaphragms is smaller, so that the phase interference of the two vibrating diaphragms in off-axis response is smaller, the comb effect is effectively reduced, and the off-axis response is smoother. The chamfered structure of the central magnetic pole enables the front part of the diaphragm to naturally form a horn-shaped coupler, so that the radiation efficiency of the diaphragm can be improved, and the lower limit of the reproduction frequency of the ribbon loudspeaker can be further reduced.

Drawings

Fig. 1 is a magnetic circuit structure diagram of a general band speaker;

fig. 2 is a magnetic circuit structure diagram of a ribbon speaker of the present invention in embodiment 1;

fig. 3 is a magnetic circuit structure diagram of a ribbon speaker of the present invention in embodiment 2;

fig. 4 is a magnetic circuit structure diagram of a ribbon speaker of the present invention in embodiment 3;

FIG. 5 is a diagram illustrating a magnetic circuit finite element analysis of the general ribbon speaker of FIG. 1;

FIG. 6 is a finite element analysis diagram of the magnetic circuit of the tape speaker of the present invention in embodiment 1;

FIG. 7 is a graph of the magnetic flux density distribution in the magnetic gap of the ribbon speaker of FIG. 1;

fig. 8 is a magnetic flux density distribution diagram in the magnetic gap of the ribbon speaker of the present invention in example 1;

the magnetic field generator comprises a permanent magnet 1, a central magnetic pole 2, an outer magnetic pole 3, a rear magnetic conduction plate 4, a vibrating diaphragm 5, a side magnetic conduction plate 6 and a magnetic gap 7.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

Example 1

As shown in fig. 2, the magnetic circuit structure of the ribbon speaker includes a central magnetic pole 2 with a corner cut structure at the front end, and outer magnetic poles 3 symmetrically disposed at both sides of the central magnetic pole 2, wherein two magnetic gaps 7 forming an included angle β in the width direction are formed between the end surfaces of the two outer magnetic poles 3 and the front end of the central magnetic pole 2, the included angle β is in a value range of 0 ° β to 180 °, and speaker diaphragms 5 are disposed in the magnetic gaps 7.

In this example, the magnetic circuit structure further includes a permanent magnet 1 and a rear magnetic conductive plate 4 serially stacked on the rear end surface of the central magnetic pole 2, two side magnetic conductive plates 6 are further disposed between the rear magnetic conductive plate 4 and the outer magnetic pole 3 and symmetrically on two sides of the central magnetic pole 2, and the permanent magnet 1 forms two symmetrical closed magnetic circuits through the central magnetic pole 2, the two magnetic gaps 7, the two outer magnetic poles 3, the two side magnetic conductive plates 6, and the rear magnetic conductive plate 4.

In this example, the tangent plane of the central pole 2 has a convex structure with respect to the magnetic gap portion.

In this example, the angle β is 90 °, and the two diaphragms 5 are perpendicular to each other.

Example 2

As shown in fig. 3, the magnetic circuit structure of the ribbon speaker includes a central magnetic pole 2 with a corner cut structure at the front end, and outer magnetic poles 3 symmetrically disposed at both sides of the central magnetic pole 2, wherein two magnetic gaps 7 forming an included angle β in the width direction are formed between the end surfaces of the two outer magnetic poles 3 and the front end of the central magnetic pole 2, the included angle β is in a value range of 0 ° β to 180 °, and speaker diaphragms 5 are disposed in the magnetic gaps 7.

In this example, the magnetic circuit structure further includes a rear magnetic conductive plate 4 closely attached to the rear end surface of the central magnetic pole 2, and two permanent magnets 1 clamped between the rear magnetic conductive plate 4 and the outer magnetic pole 3 and symmetrically arranged on both sides of the central magnetic pole 2, where the two permanent magnets 1 form two symmetrical closed magnetic circuits through the rear magnetic conductive plate 4, the central magnetic pole 2, the two magnetic gaps 7, and the two outer magnetic poles 3.

In this example, the rear magnetic conductive plate 4 and the central magnetic pole 2 can be integrally formed as a "T" shaped member.

Example 3

As shown in fig. 4, the magnetic circuit structure of the ribbon speaker includes a central magnetic pole 2 with a corner cut structure at the front end, and outer magnetic poles 3 symmetrically disposed at both sides of the central magnetic pole 2, wherein two magnetic gaps 7 forming an included angle β in the width direction are formed between the end surfaces of the two outer magnetic poles 3 and the front end of the central magnetic pole 2, the included angle β is in a value range of 0 ° β to 180 °, and speaker diaphragms 5 are disposed in the magnetic gaps 7.

In this example, the angle β is 0 °, and the two diaphragms 5 are parallel and opposite.

In this embodiment, the rear magnetic conductive plate 4 and the two side magnetic conductive plates 6 may be integrally formed as a "U" shaped member.

Based on the above, the magnetic field finite element analysis is performed on the magnetic structure of embodiment 1 and the existing magnetic structure in fig. 1, and the comparison is performed on the premise that the two magnetic circuits have the same total magnetic gap width; since the magnetic circuit structure of example 1 has two magnetic gaps 7, the width of each magnetic gap 7 in example 1 is set to 6mm, the width of the magnetic gap of the single-gap magnetic circuit in fig. 1 is set to 12mm, and other parameters for making the single-gap magnetic circuit in fig. 1 more excellent are set, such as using two times of the permanent magnet in fig. 1 as compared with example 1, and making the depth of the magnetic gap of the single-gap magnetic circuit in fig. 1 to be 20mm and 4 times of the depth of the magnetic gap 5mm in example 1 (the larger the depth of the magnetic gap is, the easier a uniform magnetic field is obtained).

FIG. 5 is a magnetic field finite element analysis diagram of the magnetic circuit of FIG. 1, and FIG. 7 is a magnetic flux density distribution diagram of the middle portion of the magnetic gap of the magnetic circuit of FIG. 1; the unevenness of the magnetic field in fig. 1 can be calculated to be (0.73-0.665)/0.665 × 100% = 9.7%.

FIG. 6 is a finite element analysis diagram of the magnetic field of the magnetic circuit in example 1, and FIG. 8 is a magnetic flux density distribution diagram in the middle of the magnetic gap of the magnetic circuit in example 1; the unevenness of the magnetic field in example 1 was calculated to be (0.605 to 0.587)/0.587 × 100% = 3.1%.

It can be seen that, on the premise that the single-gap magnetic circuit in fig. 1 is set to have more excellent parameters, the non-uniformity of embodiment 1 of the present invention is only 1/3 of the non-uniformity of the single-gap magnetic circuit in the prior art, and the following conclusions can be obtained through the result analysis of the finite element analysis of the magnetic circuit: compared with a single magnetic gap magnetic circuit, the magnetic gap of the magnetic circuit has narrower single width under the same vibration area, so that the magnetic field in the magnetic gap is more uniform and the sound distortion is lower. Although the magnetic circuit in fig. 1 uses the permanent magnet with twice volume, the magnetic flux density is improved by about 0.1T compared with that of the embodiment 1, namely, the magnetic circuit has higher magnetic field utilization rate and very small leakage flux.

In addition, the two vibrating diaphragms 5 form an included angle to radiate sound waves in different directions, the off-axis response is better, the two vibrating diaphragms 5 have smaller transverse equivalent distance, so that the phase interference of the two vibrating diaphragms in the off-axis response is smaller, the comb effect is effectively reduced, and the off-axis response is smoother. The magnetic conductive center pillar with the corner cutting structure naturally forms a horn-shaped coupler in the front part of the diaphragm, so that the radiation efficiency of the diaphragm can be improved, and the lower limit of the reproduction frequency of the band type loudspeaker can be further reduced.

It should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as a limitation of the present invention, and that changes and modifications to the above embodiments are within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.

Claims

1. A magnetic circuit structure of a belt type loudspeaker is characterized by comprising a central magnetic pole with a chamfer structure at the front end and two outer magnetic poles symmetrically arranged at the front end of the central magnetic pole, wherein the end faces of the two outer magnetic poles are parallel and opposite to the tangent plane at the front end of the central magnetic pole and form two magnetic gaps with an included angle beta in the width direction, the included angle beta is 0 degree, loudspeaker diaphragms are arranged in the magnetic gaps, and the two diaphragms are parallel and opposite.

2. A magnetic circuit structure of a ribbon speaker as claimed in claim 1 is of an internal magnetic type, wherein the magnetic circuit structure further comprises a permanent magnet and a rear magnetic conductive plate serially stacked on the rear end face of the central magnetic pole, two side magnetic conductive plates are further disposed between the rear magnetic conductive plate and the outer magnetic pole and symmetrically arranged on two sides of the central magnetic pole, and the permanent magnet forms two symmetrical closed magnetic circuits through the central magnetic pole, the two magnetic gaps, the two outer magnetic poles, the two side magnetic conductive plates, and the rear magnetic conductive plate.

3. A magnetic circuit structure of a ribbon speaker as claimed in claim 1, wherein the magnetic circuit structure further comprises a rear magnetic conductive plate closely attached to the rear end face of the central magnetic pole, and two permanent magnets clamped between the rear magnetic conductive plate and the outer magnetic pole and symmetrically disposed at two sides of the central magnetic pole, wherein the two permanent magnets form two symmetrical closed magnetic circuits through the rear magnetic conductive plate, the central magnetic pole, the two magnetic gaps, and the two outer magnetic poles.

4. The tape speaker magnetic circuit structure of claim 1, wherein the central pole section has a boss structure with respect to the magnetic gap portion.

5. The magnetic circuit structure of a ribbon speaker as claimed in claim 2, wherein the rear magnetic conductive plate and the two side magnetic conductive plates are integrally formed as a "U" shaped member.

6. A magnetic circuit structure for a ribbon speaker as claimed in claim 3, wherein the rear magnetic conductive plate and the central magnetic pole are integrally formed as a "T" shaped member.