JP2021129160A - Speaker - Google Patents

Abstract

To prevent damage of a vibration system without reducing drive force to be generated in a voice coil from a magnetic circuit even when a large current is input to the voice coil.SOLUTION: A speaker includes: a magnetic circuit unit 20 where a ring shape magnetic gap 27 is formed; a main magnet 22 for generating a magnetic field in the magnetic circuit unit 20; a cylindrical voice coil 12a which is arranged inside the magnetic gap 27 and to which a current is supplied; and a front sub-magnet 24 or a rear sub-magnet 25 which is arranged to face an amplitude range of the voice coil 12a on one end side of the magnetic gap 27 in an axial direction, so as to allow a magnetic field in a direction opposed to that of a magnetic field generated inside the magnetic gap 27 by the main magnet 22 to be generated on one end side of the magnetic gap 27 in an axial direction.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a speaker.

The speaker generates a driving force in the voice coil by the interaction between the magnetic field generated in the magnetic circuit and the current supplied to the voice coil, and responds to the vibration generated in the diaphragm with the generation of this driving force. Outputs the sound. Such a conventional speaker is disclosed in Patent Document 1, for example.

Japanese Unexamined Patent Publication No. 2001-145191

In the speaker disclosed in Patent Document 1, when a large current is input to the voice coil, the amplitude of the vibration system driven by the vibration (drive) of the voice coil becomes large. As a result, the vibration system may be damaged.

Further, a short voice coil is known as a means for suppressing an excessive amplitude of the vibration system. This short voice coil has a coil winding width narrower than a normal winding width. Therefore, the short voice coil deviates from the magnetic field generated in the magnetic circuit before the vibration system has an excessive amplitude, so that the driving force at the time of the excessive amplitude can be reduced.

However, when a short voice coil is applied to the speaker, the short voice coil cannot obtain sufficient driving force from the magnetic circuit due to the narrowed coil winding width, and even when a large current is not input, the vibration system It reduces the amplitude. Therefore, the sound quality of the speaker may deteriorate.

The present disclosure has been made to solve the above-mentioned problems, and even if a large current is input to the voice coil, the vibration system is damaged without reducing the driving force generated from the magnetic circuit to the voice coil. It is an object of the present invention to provide a speaker capable of preventing the above.

The speaker according to the present disclosure includes a magnetic circuit in which an annular magnetic gap is formed, a main magnet that generates a magnetic field in the magnetic circuit, a cylindrical voice coil that is arranged in the magnetic gap and to which a current is supplied, and a voice coil. On one end side in the axial direction of the magnetic gap, a magnetic field is provided facing the amplitude range of the voice coil, and a magnetic field opposite to the direction of the magnetic field generated in the magnetic gap by the main magnet is generated on one end side in the axial direction of the magnetic gap. It is provided with a sub-magnet on one end side.

According to the present disclosure, even if a large current is input to the voice coil, damage to the vibration system can be prevented without reducing the driving force generated in the voice coil from the magnetic circuit.

It is a vertical sectional view which shows the structure of the speaker which concerns on Embodiment 1. FIG. It is a figure which showed the direction of the magnetic field generated in the magnetic circuit unit which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the axial length of a magnetic void, and the magnitude of a magnetic flux. It is a vertical sectional view which shows the structure of the speaker which concerns on Embodiment 2. FIG. It is a figure which showed the direction of the magnetic field generated in the magnetic circuit unit which concerns on Embodiment 2. FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

Embodiment 1.
The speaker according to the first embodiment will be described with reference to FIGS. 1 to 3.

FIG. 1 is a vertical cross-sectional view showing the configuration of the speaker according to the first embodiment. FIG. 2 is a diagram showing the direction of the magnetic field generated in the magnetic circuit unit 20 according to the first embodiment.

As shown in FIGS. 1 and 2, the speaker according to the first embodiment includes a vibration system unit 10 and a magnetic circuit unit 20. The vibration system unit 10 and the magnetic circuit unit 20 are provided coaxially. In the speaker, the side where the vibration system unit 10 is arranged is the front side in the axial direction, and the side where the magnetic circuit unit 20 is arranged is the rear side in the axial direction.

As shown in FIG. 1, the vibration system unit 10 includes a frame 11, a voice coil bobbin 12, a diaphragm 13, an edge 14, a dust cap 15, a damper 16, a terminal 17, and a lead wire 18.

The frame 11 is formed in a cylindrical shape, for example, so as to gradually rise from the rear end opening that becomes the central hole toward the front end opening. The frame 11 coaxially supports a voice coil bobbin 12, a diaphragm 13, an edge 14, a dust cap 15, and a damper 16 inside the frame 11. The rear end of the frame 11 is fixed to the magnetic circuit unit 20.

The voice coil bobbin 12 has a cylindrical shape and is arranged at a substantially central portion of the vibration system unit 10. The voice coil bobbin 12 is arranged so as to penetrate the rear end opening of the frame 11. The rear end opening of the voice coil 12a is arranged in the magnetic circuit unit 20.

A voice coil 12a is wound around the outer peripheral surface of the voice coil bobbin 12 on the rear end side. A driving force in the axial direction of the speaker acts on the voice coil 12a by the interaction between the power supply related to the audio signal and the magnetic field generated in the magnetic circuit unit 20. In other words, the voice coil 12a vibrates in the front-rear direction of the speaker together with the voice coil bobbin 12.

The diaphragm 13 vibrates together with the voice coil bobbin 12, and outputs sound waves in response to this vibration. The diaphragm 13 is formed in a cone shape so as to gradually open from the rear end opening that becomes the central hole toward the front end opening. The front end opening of the voice coil bobbin 12 is inserted into the rear end opening of the diaphragm 13. The rear end opening of the diaphragm 13 and the outer peripheral surface on the front end side of the voice coil bobbin 12 are joined. Further, the front end opening of the diaphragm 13 is joined to the frame 11 via an annular edge 14.

The dust cap 15 is provided on the diaphragm 13 so as to cover the front end opening of the voice coil bobbin 12. Specifically, the dust cap 15 is inserted from the front end opening of the diaphragm 13 and is joined to the inner surface of the diaphragm 13.

The damper 16 is formed in an annular shape and in a wavy shape. Further, the damper 16 is provided between the inner surface of the frame 11 and the outer peripheral surface of the voice coil bobbin 12 on the rear side of the diaphragm 13. That is, the outer peripheral end of the damper 16 is connected to the inner surface of the frame 11, and the inner peripheral end of the damper 16 is connected to the outer peripheral surface of the voice coil bobbin 12. Therefore, the damper 16 can attenuate the vibration (drive) of the voice coil bobbin 12 in the axial direction (front-back direction) and the vibration in the radial direction (lateral direction) of the voice coil bobbin 12, respectively.

The terminal 17 is provided on the frame 11. The terminal 17 is connected to the voice coil bobbin 12 via a lead wire 18. Therefore, the current related to the audio signal is supplied from the terminal 17 to the voice coil 12a via the voice coil bobbin 12. The terminal 17 may be connected to the voice coil 12a or the diaphragm 13 via the lead wire 18.

On the other hand, as shown in FIGS. 1 and 2, the magnetic circuit unit 20 includes a yoke 21, a main magnet 22, a plate 23, a front sub magnet 24, a rear sub magnet 25, a rear support base 26, a magnetic gap 27, and a magnetic gap 27. It has a front support 28. The magnetic circuit unit 20 is an internal magnetic circuit unit. The internal magnet type magnetic circuit unit 20 is a magnetic circuit unit in which a main magnet 22 is arranged at the center thereof and magnetism is applied to the vibration system unit 10 from the inside in the radial direction thereof.

The yoke 21 is a circular hollow member made of a magnetic material. The yoke 21 supports a main magnet 22, a plate 23, a front sub magnet 24, a rear sub magnet 25, a rear support base 26, and a front support base 28 inside. Further, the front surface of the yoke 21 and the rear end of the frame 11 are joined.

The main magnet 22 is, for example, a columnar permanent magnet. The main magnet 22 has an N pole on the front end side and an S pole on the rear end side. For example, the direction of the magnetic field to the outside generated by the main magnet 22 is the direction from the north pole to the south pole. Such a main magnet 22 is provided at a substantially central portion on the bottom surface of the yoke 21. Specifically, the N pole of the main magnet 22 is arranged so as to face the front end opening of the yoke 21, and the S pole of the main magnet 22 is fixed to the bottom surface of the yoke 21.

The plate 23 is a disk member made of a magnetic material. The plate 23 is provided at the front end of the main magnet 22. Further, the plate 23 is arranged in the front end opening of the yoke 21. An annular magnetic gap 27 is formed between the inner peripheral surface of the front end opening of the yoke 21 and the outer peripheral surface of the plate 23. The magnetic gap 27 indicates a space sandwiched between the inner peripheral surface of the front end opening of the yoke 21 and the outer peripheral surface of the plate 23. The voice coil 12a described above is arranged in the magnetic gap 27 thereof.

Therefore, as shown in FIG. 2, the magnetic flux generated from the north pole of the main magnet 22 passes through the inside of the plate 23 and then passes through the magnetic gap 27 from the inside in the radial direction to the outside in the radial direction, and the yoke 21 To reach. Then, the magnetic flux that has reached the yoke 21 passes through the inside of the yoke 21 and then returns to the S pole of the main magnet 22.

Therefore, the magnetic flux acts on the voice coil 12a arranged in the magnetic gap 27 from the radial inside to the radial outside of the magnetic gap 27. As described above, when the voice coil 12a receives the current related to the audio signal in the state where the magnetic flux is applied, the voice coil 12a vibrates in the front-rear direction because it receives the driving force in the front-rear direction based on Fleming's left-hand rule. As a result, the voice coil 12a transmits the vibration to the diaphragm 13, and the diaphragm 13 outputs the sound according to the transmitted vibration.

The front sub-magnet 24 is, for example, an annular permanent magnet. The front sub-magnet 24 has an S pole on the outer peripheral side and an N pole on the inner peripheral side. For example, the direction of the magnetic field to the outside generated by the front sub-magnet 24 is the direction from the north pole to the south pole. Of these, the direction of the magnetic field generated by the front sub-magnet 24 on the front end side of the magnetic gap 27 is from the radially outer side to the radial inner side of the magnetic gap 27, and the magnetic gap 27 is directed by the main magnet 22. The direction of the magnetic field generated inside is opposite.

The front sub-magnet 24 is attached to the front surface of the plate 23 via a columnar front support 28. At this time, the front sub-magnet 24 is provided on the front end side of the magnetic gap 27 facing the amplitude range of the voice coil 12a. Specifically, the front sub-magnet 24 is arranged on the front side of the magnetic gap 27 and inside the magnetic gap 27 in the radial direction. Further, the front sub-magnet 24 is arranged on the front side of the voice coil 12a and inside the voice coil 12a in the radial direction. The outer peripheral surface of the front sub-magnet 24, which is the S pole, faces the inner peripheral surface of the voice coil bobbin 12.

Therefore, as shown in FIG. 2, when the magnetic flux emitted from the north pole of the front sub-magnet 24 reaches the front end side of the magnetic gap 27, it is along the front end and radially from the outside of the magnetic gap 27 in the radial direction. Heading inward, it returns to the south pole of the front sub-magnet 24.

Therefore, in the voice coil 12a that has entered the magnetic field of the front sub-magnet 24, the magnetic flux generated from the front sub-magnet 24 is changed to the magnetic flux emitted from the main magnet 22 and is the diameter of the magnetic gap 27. It acts from the outside in the direction to the inside in the radial direction. As a result, the voice coil 12a brakes due to the magnetic flux of the front sub-magnet 24 against the excessive amplitude toward the front side, and suppresses the driving force (vibration) to the diaphragm 13.

The rear sub-magnet 25 is, for example, an annular permanent magnet. The rear sub-magnet 25 has an N pole on the outer peripheral side and an S pole on the inner peripheral side. For example, the direction of the magnetic field to the outside generated by the rear sub-magnet 25 is the direction from the north pole to the south pole. Of these, the direction of the magnetic field generated by the rear sub-magnet 25 on the rear end side of the magnetic gap 27 is from the radial outer side to the radial inner side of the magnetic gap 27, and the magnetic gap 27 is directed by the main magnet 22. The direction of the magnetic field generated inside is opposite.

The rear sub-magnet 25 is fixed to the inner side surface and the bottom surface of the yoke 21 via an annular rear support base 26. At this time, the rear sub-magnet 25 is provided on the rear end side of the magnetic gap 27 facing the amplitude range of the voice coil 12a. Specifically, the rear sub-magnet 25 is arranged on the rear side of the magnetic gap 27 and on the radial side of the magnetic gap 27. Further, the rear sub-magnet 25 is arranged on the rear side of the voice coil 12a and on the outer side in the radial direction of the voice coil 12a.

Therefore, as shown in FIG. 2, when the magnetic flux emitted from the north pole of the rear sub-magnet 25 reaches the rear end side of the magnetic gap 27, the diameter is along the rear end of the magnetic gap 27 from the radial outside of the magnetic gap 27. It goes inward in the direction and returns to the south pole of the rear sub-magnet 25.

Therefore, in the voice coil 12a that has entered the magnetic field of the rear sub-magnet 25, the magnetic flux emitted from the rear sub-magnet 25 changes to the magnetic flux emitted from the main magnet 22, and the magnetic flux emitted from the rear sub-magnet 25 is radially outside the magnetic gap 27. Acts inward in the radial direction. As a result, the voice coil 12a brakes due to the magnetic flux of the rear sub-magnet 25 against the excessive amplitude toward the rear side, and suppresses the driving force (vibration) to the diaphragm 13.

The above-mentioned magnetic circuit unit 20 includes a front sub-magnet 24 on the front end side of the magnetic gap 27, and a rear sub magnet 25 on the rear end side of the magnetic gap 27. At least one of the rear sub-magnets 25 may be provided. Here, the one end side in the axial direction of the magnetic gap 27 is the front end side or the rear end side of the magnetic gap 27, and the other end side in the axial direction of the magnetic gap 27 indicates the opposite side of the one end side in the axial direction. There is. At this time, the sub-magnet arranged on one end side in the axial direction of the magnetic gap 27 is a sub-magnet on one end side, and the sub-magnet arranged on the other end side in the axial direction of the magnetic gap 27 is a sub magnet on the other end side. ..

Further, in the magnetic circuit unit 20 shown in FIGS. 1 and 2, the distance between the front end of the magnetic gap 27 and the front sub-magnet 24 and the distance between the rear end of the magnetic gap 27 and the rear sub-magnet 25 Is set to the same distance by adjusting the thickness of the front support base 28 and the rear support base 26. At this time, the magnetic flux generated in the magnetic gap 27, the magnetic flux generated by the front sub-magnet 24, and the magnetic flux generated by the rear sub-magnet 35 have uniform distances. Therefore, the vibration system unit 10 can suppress the excessive amplitude of the voice coil 12a at the same distance from the magnetic gap 27 to the front side and the rear side.

FIG. 3 is a diagram showing the relationship between the axial length of the magnetic gap 27 and the magnitude of the magnetic flux. The horizontal axis of FIG. 3 indicates the axial length (mm) of the magnetic gap 27. The vertical axis of FIG. 3 indicates the magnitude (Wb) of the magnetic flux.

For example, in the magnetic circuit unit 20 shown in FIG. 3, the magnetic gap 27 is formed in the range of 3.5 to 8.0 mm, and the axial length of the magnetic gap 27 is 4.5 mm. There is. The front end side of the magnetic gap 27 is shown in the range of 0.0 to 3.5, and the rear end side of the magnetic gap 27 is shown in the range of 8.0 to 10.0.

As shown in FIG. 3, the magnetic field generated by the front sub-magnet 24 makes the magnetic flux on the front end side of the magnetic gap 27 a negative value, and the magnetic field generated by the rear sub-magnet 25 is after the magnetic gap 27. The magnetic flux on the end side is set to a negative value. On the other hand, the magnetic field generated by the main magnet 22 remains a positive value without being affected by the magnetic fields generated by the front sub-magnet 24 and the rear sub-magnet 25.

As a result, the voice coil 12a is arranged in the magnetic gap 27 when a large current is not input, and receives a driving force in the magnetic gap 27. Further, when a large current is input, the voice coil 12a deviates from the magnetic gap 27 and excessively swings toward the front end side or the rear end side of the magnetic gap 27, and the driving force thereof is on the front end side or the rear end side. Is broken.

As described above, the speaker according to the first embodiment is arranged in the magnetic gap 27, the magnetic circuit unit 20 in which the annular magnetic gap 27 is formed, the main magnet 22 that generates a magnetic field in the magnetic circuit unit 20, and the current. The direction of the magnetic field generated in the magnetic gap 27 by the main magnet 22 provided with the cylindrical voice coil 12a to which the magnet 22 is supplied and facing the amplitude range of the voice coil 12a on one end side in the axial direction of the magnetic gap 27. The front sub-magnet 24 or the rear sub-magnet 25 that generates a magnetic field in the opposite direction to the above is generated on one end side in the axial direction of the magnetic gap 27. Therefore, even if a large current is input to the voice coil 12a, the speaker can prevent the vibration system unit 10 from being damaged without reducing the driving force generated from the magnetic circuit unit 20 to the voice coil 12a.

Embodiment 2.
The speaker according to the second embodiment will be described with reference to FIGS. 4 and 5.

FIG. 4 is a vertical cross-sectional view showing the configuration of the speaker according to the second embodiment. FIG. 5 is a diagram showing the direction of the magnetic field generated in the magnetic circuit unit according to the second embodiment.

As shown in FIGS. 4 and 5, the speaker according to the second embodiment has been changed from the inner magnetic circuit unit 20 to the outer magnetic circuit unit 30 with respect to the speaker according to the first embodiment. It is composed. Other configurations are the same as those of the speaker according to the first embodiment. Therefore, in the speaker according to the second embodiment, the same reference numerals are given to the same configurations as the speakers according to the first embodiment, and the description of the configurations will be omitted.

The speaker according to the second embodiment includes a vibration system unit 10 and a magnetic circuit unit 30.

The magnetic circuit unit 30 includes a pole piece 31, a main magnet 32, a plate 33, a front sub magnet 34, a rear sub magnet 35, a rear support base 36, a magnetic gap 37, and a front support base 38. As described above, the magnetic circuit unit 30 is an external magnetic type magnetic circuit unit. The external magnet type magnetic circuit unit 30 is a magnetic circuit unit in which a main magnet 32 is arranged on the outer peripheral portion thereof to apply magnetism to the vibration system unit 10 from the outside in the radial direction thereof.

The pole piece 31 is a circular member made of a magnetic material. The pole piece 31 has a columnar center pole 31a at its center. The center pole 31a is a portion that protrudes toward the front side. Further, the pole piece 31 supports a main magnet 32, a plate 33, a front sub magnet 34, a rear sub magnet 35, a rear support base 36, and a front support base 38 on the front portion thereof.

The main magnet 32 is, for example, an annular permanent magnet. The main magnet 32 has an S pole on the front end side and an N pole on the rear end side. For example, the direction of the magnetic field to the outside generated by the main magnet 32 is the direction from the north pole to the south pole. Such a main magnet 32 is provided on the front surface of the pole piece 31 on the radial outer side of the center pole 31a. Specifically, the S pole of the main magnet 32 faces the front side, and the N pole of the main magnet 32 is fixed to the front surface of the pole piece 31.

The plate 33 is an annular member made of a magnetic material. The plate 33 is provided at the front end of the main magnet 32. The inner peripheral surface of the plate 33 faces the outer peripheral surface of the center pole 31a. An annular magnetic gap 37 is formed between the inner peripheral surface of the plate 33 and the outer peripheral surface of the center pole 31a. The voice coil 12a described above is arranged in the magnetic gap 37.

Therefore, as shown in FIG. 5, the magnetic flux emitted from the north pole of the main magnet 32 passes through the inside of the pole piece 31 and then passes through the magnetic gap 37 from the inside in the radial direction to the outside in the radial direction, and the plate. Reach 33. Then, the magnetic flux that has reached the plate 33 passes through the inside of the plate 33 and then returns to the S pole of the main magnet 32.

Therefore, the magnetic flux acts on the voice coil 12a arranged in the magnetic gap 37 from the radial inside to the radial outside of the magnetic gap 37. As described above, when the voice coil 12a receives the current related to the audio signal in the state where the magnetic flux is applied, the voice coil 12a vibrates in the front-rear direction because it receives the driving force in the front-rear direction based on Fleming's left-hand rule. As a result, the voice coil 12a transmits the vibration to the diaphragm 13, and the diaphragm 13 outputs the sound according to the transmitted vibration.

The front sub-magnet 34 is, for example, an annular permanent magnet. The front sub-magnet 34 has an S pole on the outer peripheral side and an N pole on the inner peripheral side. For example, the direction of the magnetic field to the outside generated by the front sub-magnet 34 is the direction from the north pole to the south pole. Of these, the direction of the magnetic field generated by the front sub-magnet 34 on the front end side of the magnetic gap 37 is from the radial outer side to the radial inner side of the magnetic gap 37, and the magnetic gap 37 is directed by the main magnet 32. The direction of the magnetic field generated inside is opposite.

The front sub-magnet 34 is attached to the front end of the center pole 31a via a columnar front support 28. At this time, the front sub-magnet 34 is provided on the front end side of the magnetic gap 27 facing the amplitude range of the voice coil 12a. Specifically, the front sub-magnet 34 is arranged on the front side of the magnetic gap 37 and inside the magnetic gap 37 in the radial direction. Further, the front sub-magnet 34 is arranged on the front side of the voice coil 12a and inside the voice coil 12a in the radial direction. The outer peripheral surface of the front sub-magnet 34, which is the S pole, faces the inner peripheral surface of the voice coil bobbin 12.

Therefore, as shown in FIG. 5, when the magnetic flux emitted from the north pole of the front sub-magnet 34 reaches the front end side of the magnetic gap 37, it is along the front end and radially from the outside of the magnetic gap 37 in the radial direction. Heading inward, it returns to the south pole of the front sub-magnet 34.

Therefore, in the voice coil 12a that has entered the magnetic field of the front sub-magnet 34, the magnetic flux emitted from the front sub-magnet 34 is changed to the magnetic flux emitted from the main magnet 32, and the magnetic flux emitted from the front sub-magnet 34 is the diameter of the magnetic gap 37. It acts from the outside in the direction to the inside in the radial direction. As a result, the voice coil 12a brakes due to the magnetic flux of the front sub-magnet 34 against the excessive amplitude toward the front side, and suppresses the driving force (vibration) to the diaphragm 13.

The rear sub-magnet 35 is, for example, an annular permanent magnet. The rear sub-magnet 35 has an N pole on the outer peripheral side and an S pole on the inner peripheral side. For example, the direction of the magnetic field to the outside generated by the rear sub-magnet 35 is the direction from the north pole to the south pole. Of these, the direction of the magnetic field generated by the rear sub-magnet 35 along the rear end of the magnetic gap 37 is from the radially outer side to the radial inner side of the magnetic gap 37, and is magnetized by the main magnet 32. The direction of the magnetic field generated in the gap 27 is opposite to that of the magnetic field.

The rear sub-magnet 35 is fixed to the front surface of the pole piece 31 via a rear support base 36 forming an annular shape. At this time, the rear sub-magnet 35 is provided on the rear end side of the magnetic gap 37 so as to face the amplitude range of the voice coil 12a. Specifically, the rear sub-magnet 35 is arranged on the rear side of the magnetic gap 37 and on the radial side of the magnetic gap 37. Further, the rear sub-magnet 35 is arranged on the rear side of the voice coil 12a and on the outer side in the radial direction of the voice coil 12a.

Therefore, as shown in FIG. 5, when the magnetic flux emitted from the north pole of the rear sub-magnet 35 reaches the rear end side of the magnetic gap 37, the diameter is along the rear end of the magnetic gap 37 from the radial outside of the magnetic gap 37. It goes inward in the direction and returns to the south pole of the rear sub-magnet 35.

Therefore, in the voice coil 12a that has entered the magnetic field of the rear sub-magnet 35, the magnetic flux generated from the rear sub-magnet 35 is changed to the magnetic flux emitted from the main magnet 32, and the magnetic flux generated from the rear sub-magnet 35 is radially outside the magnetic gap 37. Acts inward in the radial direction. As a result, the voice coil 12a brakes due to the magnetic flux of the rear sub-magnet 35 against the excessive amplitude toward the rear side, and suppresses the driving force (vibration) to the diaphragm 13.

Therefore, the voice coil 12a is arranged in the magnetic gap 37 when a large current is not input, and receives a driving force in the magnetic gap 37. Further, when a large current is input, the voice coil 12a deviates from the magnetic gap 27 and excessively swings toward the front end side or the rear end side of the magnetic gap 27, and the driving force thereof is on the front end side or the rear end side. Is broken.

The above-mentioned magnetic circuit unit 30 is provided with a front sub-magnet 34 on the front end side of the magnetic gap 37, while the rear sub magnet 35 is provided on the rear end side of the magnetic gap 37. At least one of the rear sub-magnets 35 may be provided.

As described above, the speaker according to the second embodiment is arranged in the magnetic gap 37, the magnetic circuit unit 30 in which the annular magnetic gap 37 is formed, the main magnet 32 that generates a magnetic field in the magnetic circuit unit 30, and the current. The direction of the magnetic field generated in the magnetic gap 37 by the main magnet 32, which is provided so as to face the amplitude range of the voice coil 12a on one end side of the magnetic gap 37 in the axial direction and the cylindrical voice coil 12a to which A front sub-magnet 34 or a rear sub-magnet 35 that generates a magnetic field in the opposite direction to the above is generated on one end side in the axial direction of the magnetic gap 37. Therefore, even if a large current is input to the voice coil 12a, the speaker can prevent the vibration system unit 10 from being damaged without reducing the driving force generated from the magnetic circuit unit 30 to the voice coil 12a.

In the present disclosure, within the scope of the disclosure, any combination of the embodiments, modification of any component in each embodiment, or omission of any component in each embodiment can be omitted. It is possible.

10 Vibration system unit, 11 frame, 12 voice coil bobbin, 12a voice coil, 13 vibrating plate, 14 edge, 15 dust cap, 16 damper, 17 terminal, 18 lead wire, 20 magnetic circuit unit, 21 yoke, 22 main magnet, 23 Plate, 24 front sub magnet, 25 rear sub magnet, 26 rear support, 27 magnetic gap, 28 front support, 30 magnetic circuit unit, 31 pole piece, 31a center pole, 32 main magnet, 33 plate, 34 front Part sub magnet, 35 rear sub magnet, 36 rear support, 37 magnetic gap, 38 front support.

Claims (5)

A magnetic circuit in which an annular magnetic gap is formed,
The main magnet that generates a magnetic field in the magnetic circuit,
A cylindrical voice coil arranged in the magnetic gap and supplied with an electric current,
A magnetic field provided on one end side in the axial direction of the magnetic gap facing the amplitude range of the voice coil and in the direction opposite to the direction of the magnetic field generated in the magnetic gap by the main magnet is the axis of the magnetic gap. A speaker characterized by having a sub-magnet on one end side that generates magnetism on one end side in the direction. On the other end side in the axial direction of the magnetic gap, a magnetic field provided in the amplitude range of the voice coil and in the direction opposite to the direction of the magnetic field generated in the magnetic gap by the main magnet is applied to the magnetic gap. The speaker according to claim 1, further comprising a sub-magnet on the other end side that is generated on the other end side in the axial direction. The distance between one end of the magnetic gap in the axial direction and the sub-magnet on one end side and the distance between the other end in the axial direction of the magnetic gap and the sub-magnet on the other end side are the same. 2. The speaker according to claim 2. The magnetic circuit
The speaker according to any one of claims 1 to 3, wherein the main magnet is an internal magnetic type magnetic circuit arranged inside the voice coil in the radial direction. The magnetic circuit
The speaker according to any one of claims 1 to 3, wherein the main magnet is an external magnetic type magnetic circuit arranged outside in the radial direction of the voice coil.

Images