How to adjust the speakers

Abstract

To provide a speaker capable of adjusting relative positions of a magnetic circuit and a voice coil in a manufacture process, and an adjustment method for the speaker.SOLUTION: In a speaker 1, a support 2 is divided into a first support 3 and a second support 4, a magnetic circuit 10 is supported by the first support 3 and a diaphragm 6, a bobbin 15, a voice coil 16 and a damper member 8 are supported by the second support 4. A magnet 21 for detection constituting a vibration detection device 20 is fixed to the bobbin 15, and a magnetic sensor 22 is fixed to the magnetic circuit 10. The first support 3 and the second support 4 are connected via a position adjustment mechanism 5 which is a screw connection mechanism. The first support 3 and the second support 4 are relatively rotated, thereby adjusting relative positions of a magnetic gap G and the voice coil 16 in a longitudinal direction (Y1-Y2 direction).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a speaker that allows adjustment of the relative position between a voice coil and a magnetic circuit, and a method for adjusting the speaker. [Background technology]

[0002] Patent Documents 1 and 2 describe speakers provided with a sensor that detects vibration of a diaphragm. The speaker described in Patent Document 1 is provided with a piezoelectric film as a sensor for detecting vibration, and the piezoelectric film is provided between a sensor support member fixed to a magnet and a coil bobbin. The vibration frequency of the cone paper is detected by the piezoelectric film, and the vibration of the cone paper is controlled based on the detection output.

[0003] The speaker described in Patent Document 2 has a pair of light-emitting diodes and a pair of phototransistors fixed to face each other on a support member fixed to the upper part of a support body. A vibrating member is fixed to a center cap provided in the center of a paper cone. The vibrating member has two slits formed therein, which penetrate in the direction in which the pair of light-emitting diodes and photodiodes face each other. The amount of light emitted from the light-emitting diodes passing through the slits and detected by the photodiodes varies according to the amount of movement of the paper cone. An error signal is generated based on a detection signal from the phototransistor, and the error signal is provided to a speaker driving circuit to perform motional feedback control. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-306339 A [Patent Document 2] Patent No. 6667186 Summary of the Invention [Problem to be solved by the invention]

[0005] In both of the speakers described in Patent Documents 1 and 2, feedback control is performed to correct the deviation in the relative position between the magnetic circuit and the voice coil when a voice current is applied to the voice coil, causing the cone paper to vibrate and produce sound.

[0006] On the other hand, in the manufacturing process of a speaker, it is unavoidable that the relative position between the magnetic circuit and the voice coil will vary. If the feedback control described in Patent Document 1 or Patent Document 2 is performed on a speaker in which the relative position between the magnetic circuit and the voice coil is misaligned, the correction signal (offset signal) superimposed on the audio signal when the speaker is producing sound tends to become too large, and the dark current tends to increase. As a result, the current consumption increases, the amount of heat generated by the voice coil also increases, and sound quality deteriorates.

[0007] The present invention solves the above-mentioned problems of the conventional art, and is capable of adjusting the relative position of the magnetic circuit and the voice coil during the manufacturing process. Speakers that can The present invention aims to provide a method for adjusting the above. [Means for solving the problem]

[0008] The present invention provides a magnetic sensor comprising: a first support supporting a magnetic circuit; a second support supporting a diaphragm; a voice coil inserted into a magnetic gap of the magnetic circuit and vibrating together with the diaphragm; a detection magnet vibrating together with the voice coil; and a magnetic sensor supported by the magnetic circuit or the first support and detecting a magnetic flux emitted from the detection magnet; A speaker in which the first support and the second support are connected via a position adjustment mechanism for changing a relative position in a front-rear direction along a vibration direction of the voice coil, An adjustment current is applied to the voice coil to move the voice coil and the detection magnet in a forward / backward direction, the detection magnetic flux emitted from the detection magnet is detected by the magnetic sensor, the amount of deviation in the relative position in the forward / backward direction between the first support and the second support is calculated, and the relative position of the first support and the second support is changed by the position adjustment mechanism in a direction to eliminate the amount of deviation.

[0009] In the speaker adjusting method of the present invention, it is preferable that the adjustment current is changed with respect to time based on a trigonometric function or based on a waveform approximating a trigonometric function.

[0010] In the speaker adjustment method of the present invention, for example, the position adjustment mechanism includes: The first support, and The above Second This is a screw connection mechanism in which a spiral is formed centered on a center line that passes through the center of the support and extends in the front-to-rear direction.

[0011] Speaker of the present invention How to adjust It is preferable that the position adjustment mechanism is provided at a position away from a magnetic flux path formed by the magnetic circuit. Effect of the Invention

[0014] Speaker of the present invention How to adjust In the manufacturing process, for example, the relative position between the magnetic circuit and the voice coil can be adjusted to be appropriate by changing the relative position between the first support and the second support using a position adjustment mechanism. This improves the quality of the sound generated by the vibration of the diaphragm. Also, even when feedback control is performed using a vibration detection device having a detection magnet and a magnetic sensor, it becomes possible to prevent an excessive offset signal from being superimposed on the audio signal.

[0015] The speaker adjustment method of the present invention enables highly accurate adjustment of the relative positions of the magnetic circuit and the voice coil by applying an adjustment current to the voice coil to move the diaphragm, voice coil, and detection magnet back and forth, and calculating the amount of positional deviation between the magnetic circuit and the voice coil from the detection output of the magnetic sensor. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a partial cross-sectional view showing a speaker according to a first embodiment of the present invention; [Diagram 2] FIG. 4 is a partial cross-sectional view showing a speaker according to a second embodiment of the present invention; [Diagram 3] FIG. 1 is a partial cross-sectional view showing a modified example of the speaker according to the first embodiment of the present invention; [Figure 4] A flow chart showing steps of a speaker adjustment method; [Diagram 5] A flowchart showing a feedback control process when a speaker is generating sound; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] In the speaker 1 of the first embodiment of the present invention shown in Fig. 1, the Y1-Y2 direction is the front-rear direction, with the Y1 direction being the front, which is the sound-producing direction, and the Y2 direction being the rear. Fig. 1 shows a center line O that extends in the front-rear direction (Y1-Y2 direction). The main part of the speaker 1 has a structure that is almost rotationally symmetrical about the center line O.

[0018] The speaker 1 shown in FIG. 1 has a support 2. The support 2 has a first support 3 and a second support 4. The support 2 is a frame formed of a non-magnetic material or a magnetic material, the first support 3 is the first frame, and the second support 4 is the second frame. The first support 3 and the second support 4 are connected via a position adjustment mechanism 5, which is a screw coupling mechanism. In the screw coupling mechanism, a male screw portion is formed in the first support 3, and a female screw portion is formed in the second support 4. The male screw portion and the female screw portion have a helical thread and a screw groove centered on a center line O. By rotating the first support 3 and the second support 4 relatively around the center line O, the relative positions of the first support 3 and the second support 4 in the front-rear direction can be changed.

[0019] A magnetic circuit 10 is fixed to the rear end surface 3a of the first support 3 by means of adhesion or the like. The magnetic circuit 10 has a ring-shaped driving magnet 11 centered on a center line O, a ring-shaped opposing yoke 12 joined to the front of the driving magnet 11, and a rear yoke 13 joined to the rear of the driving magnet 11. A cylindrical center yoke 14 protruding forward from the rear yoke 13 is provided inside the driving magnet 11 and the opposing yoke 12. The center yoke 14 is fixed to the rear yoke 13 or formed integrally with the rear yoke. The opposing yoke 12, the rear yoke 13, and the center yoke 14 are formed of a magnetic material, i.e., a magnetic metal material. A magnetic gap G is formed along a circumference centered on the center line O between the inner peripheral surface of the ring-shaped opposing yoke 12 and the outer peripheral surface of the center yoke 14. In the magnetic circuit 10, the driving magnetic flux F1 generated from the driving magnet 11 travels from the opposing yoke 12 across the magnetic gap G to the center yoke 14 and the rear yoke 13, and the driving magnetic flux F1 travels across the voice coil 16 located within the magnetic gap G.

[0020] A diaphragm 6 is provided inside the second support 4. The diaphragm 6 has a conical shape. A front end 4a of the second support 4 and an outer peripheral end 6a of the diaphragm 6 are joined via an elastically deformable edge member 7. A rear end 4b of the second support 4 and an inner peripheral end 6b of the diaphragm 6 are connected via an elastically deformable damper member 8 having a corrugated cross section. A center cap 9 is fixed to the center of the diaphragm 6. The diaphragm 6 is supported by the edge member 7 and the damper member 8 so as to be able to vibrate freely in the front-rear direction (Y1-Y2 direction).

[0021] A bobbin 15 is adhered and fixed to the inner peripheral end 6b of the diaphragm 6, and the voice coil 16 is provided at the rear end of the bobbin 15. The coated conductor wire constituting the voice coil 16 is wound cylindrically with a predetermined number of turns around a center line O. The voice coil 16 is located within the magnetic gap G of the magnetic circuit 10. The magnetic circuit 10 and the voice coil 16 constitute a magnetic drive unit.

[0022] The speaker 1 is provided with a vibration detection device 20. The vibration detection device 20 is composed of a detection magnet 21 and a magnetic sensor 22. The detection magnet 21 is fixed to the bobbin 15 so that it can vibrate together with the voice coil 16 and the diaphragm 6. The magnetic sensor 22 is fixed to the front surface of the opposing yoke 12 that constitutes the magnetic circuit 10. Alternatively, the magnetic sensor 22 may be fixed to the first support 3. The magnetic sensor 22 is a Hall element or a magnetoresistance effect element, and the horizontal component (component perpendicular to the center line O and directed in the radial direction) of the detection magnetic flux F2 emitted from the detection magnet 21 is detected by the magnetic sensor 22. If a small and lightweight magnetic sensor 22 is used, the detection magnet 21 may be fixed to the magnetic circuit 10 or the first support 3, and the magnetic sensor 22 may be fixed to the bobbin 15.

[0023] A control unit provided in the speaker 1 performs feedback control based on the detection output from the magnetic sensor 22. In this feedback control, the amount of misalignment between the magnetic circuit 10 and the voice coil 16 in the front-rear direction (Y1-Y2) is calculated based on the detection output from the magnetic sensor 22, and a current (correction signal) for correcting this is superimposed on the voice current (audio signal).

[0024] The speaker 1 shown in FIG. 1 is provided with a position adjustment mechanism 5, which is a screw connection mechanism, and thus the relative position between the magnetic gap G of the magnetic circuit 10 and the voice coil 16 in the front-rear direction (Y1-Y2 direction) can be adjusted by rotating the first support 3 and the second support 4 relative to each other. However, when the first support 3 and the second support 4 are rotated relative to each other, the relative positions of the detection magnet 21 and the magnetic sensor 22 change in the circumferential direction centered on the center line O. Therefore, it is preferable that the detection magnet 21 is formed in a partial ring shape having a predetermined length in the circumferential direction centered on the center line O or a ring shape that is continuous over 360 degrees, and when the first support 3 and the second support 4 are rotated relative to each other, the detection magnet 21 and the magnetic sensor 22 are positioned in the same cross section including the center line O shown in FIG. 1.

[0025] Furthermore, the first support 3 and the second support 4 may be rotated relative to each other in a state in which the outer circumferential ends of both the edge member 7 and the damper member 8 are placed without being adhesively fixed to the second support 4, that is, in such a state that the edge member 7, the damper member 8, the diaphragm 6 and the bobbin 15 do not follow the rotation of the second support 4 during the adjustment operation, to adjust the relative position in the front-to-rear direction between the magnetic gap G of the magnetic circuit 10 and the voice coil 16. If the outer circumferential ends of both the edge member 7 and the damper member 8 are adhesively fixed to the second support 4 after this adjustment operation, it becomes unnecessary to form the detection magnet 21 into a partial ring shape or a ring shape.

[0026] FIG. 2 shows a speaker 101 according to a second embodiment of the present invention. The speaker 101 is provided with a frame 102 made of a magnetic or non-magnetic material, and a diaphragm 6 is supported on the frame 102 via an edge member 7 and a damper member 8 so as to be able to vibrate freely in the front-rear direction (Y1-Y2 direction). A center cap 9 is fixed to the center of the diaphragm 6. A bobbin 15 is fixed to an inner peripheral end 6b of the diaphragm 6, and a voice coil 16 is provided at the rear end of the bobbin 15.

[0027] A magnetic circuit 30 is fixed to the rear of the frame 102. The magnetic circuit 30 includes a cylindrical driving magnet 34 located on the center line O, a rear yoke 31 fixed to the rear surface of the driving magnet 34, and a center yoke 35 fixed to the front surface of the driving magnet 34. The rear yoke 31 and the center yoke 35 are made of a magnetic metal material. The rear yoke 31 is divided into a first support 32 and a second support 33. The magnetic circuit 30 is supported by the first support 32. The second support 33 constitutes a part of the magnetic circuit 10, and the diaphragm 6 and the voice coil 16 are supported by the second support 33 via the frame 102.

[0028] The first support 32 and the second support 33 are connected via a position adjustment mechanism 5, which is a screw coupling mechanism. In the screw coupling mechanism, a male thread is formed in the first support 32, and a female thread is formed in the second support 33. The male thread and the female thread have a helical thread and a screw groove centered on a center line O. By rotating the first support 32 and the second support 33 relatively around the center line O, the relative positions of the first support 32 and the second support 33 in the front-to-rear direction can be changed.

[0029] The detection magnet 21 constituting the vibration detection device 20 is fixed to the bobbin 15, and the magnetic sensor 22 is fixed to the front surface of the center yoke 35 constituting the magnetic circuit 30. It is preferable that the detection magnet 21 has a length dimension within a predetermined angle range in the circumferential direction centered on the center line O so that the detection magnet 21 and the magnetic sensor 22 are positioned on the same cross section including the center line O when the first support 32 and the second support 33, which are connected by the screw connection mechanism of the position adjustment mechanism 5, rotate relatively.

[0030] In both the speaker 1 shown in Fig. 1 and the speaker 101 shown in Fig. 2, a first support supporting a magnetic circuit and a second support supporting a diaphragm and a voice coil are connected by a position adjustment mechanism 5, which is a screw connection mechanism. In the speaker 1 shown in Fig. 1, the position adjustment mechanism 5 is provided on a support (frame) 2 located forward of the magnetic circuit 10, and the position adjustment mechanism 5 is located outside the path of the driving magnetic flux F1 in the magnetic circuit 10. Therefore, the presence of the position adjustment mechanism 5 does not cause magnetic resistance in the path of the driving magnetic flux F1. In this respect, the structure of the speaker 1 shown in Fig. 1 is preferable.

[0031] The speaker 201 shown in FIG. 3 is a modified example of the speaker 1 shown in FIG. In speaker 201 shown in FIG. 3, support 2, which is a frame, is divided into a first support 3 and a second support 4, with magnetic circuit 10 and magnetic sensor 22 supported on first support 3, and diaphragm 6, voice coil 16, and detection magnet 21 supported on second support 4.

[0032] The first support 3 and the second support 4 are connected via a position adjustment mechanism 40. The position adjustment mechanism 40 has key grooves 41 formed at multiple locations in the circumferential direction of the first support 3 and key portions 42 formed at multiple locations in the circumferential direction of the second support 4. The key grooves 41 and the key portions 42 extend linearly in the front-rear direction (Y1-Y2 direction), and the key portions 42 are fitted inside the key grooves 41 so as to be slidable in the front-rear direction. The position adjustment mechanism 40 includes a fixing screw 43. In a location where the key grooves 41 and the key portions 42 are not provided, a female threaded hole is formed in the first support 3, and an elongated hole extending in the front-rear direction is formed in the second support 4, and the fixing screw 43 is inserted into the elongated hole and screwed into the female threaded hole.

[0033] The relative positions of the first support 3 and the second support 4 in the front-to-rear direction can be adjusted by sliding the key portion 42 of the position adjustment mechanism 40 inside the key groove 41. After completing the adjustment, the first support 3 and the second support 4 are fixed to each other by tightening the fixing screw 43. Note that in the position adjustment mechanism 40, the key portion 42 may be provided on the first support 3, and the key groove 41 may be provided on the second support 4.

[0034] A method for adjusting the speakers will be described with reference to the flowchart shown in Fig. 4. This adjustment is performed at the final stage of the manufacturing process of the speakers 1, 101, and 201. In the flowcharts of Fig. 4 and Fig. 5, "Step" is indicated as "ST."

[0035] In the magnetic circuits 10, 30 of the speakers 1, 101, 201, the driving magnetic flux F1 crosses the voice coil 16 located in the magnetic gap G. When the adjustment work is started at ST1 shown in FIG. 4, an adjustment current is applied to the voice coil 16 at ST2. The waveform of the adjustment current changes with time based on a trigonometric function or changes in a manner similar to a trigonometric function. When the adjustment current is applied to the voice coil 16, an electromagnetic force acts in the front-rear direction on the voice coil 16 on which the driving magnetic flux F1 acts, and the diaphragm 6 and the detection magnet move together in the front-rear direction. The horizontal component of the detection magnetic flux F2 emitted from the detection magnet 21 is detected by the magnetic sensor 22, and the detection output has a waveform that reflects the movement distance of the voice coil 16 and the detection magnet 21 in the front-rear direction.

[0036] In ST3, the adjustment circuit monitors the change in the detection output of the magnetic sensor 22. The ideal detection waveform when the relative position in the front-to-rear direction of the magnetic gap G of the magnetic circuit 10 and the voice coil 16 is as designed is compared with the detection waveform of the magnetic sensor 22, and if the deviation is equal to or greater than a threshold value, the process proceeds to ST4, where the height of the voice coil 16 is adjusted. This adjustment is performed by changing the relative position in the front-to-rear direction of the first support 3 (32) and the second support 4 (33) using the position adjustment mechanism 5 (40). When the deviation between the ideal detection output and the detection output of the magnetic sensor 22 becomes less than the threshold value as a result of this adjustment, the adjustment is completed in ST5.

[0037] By performing the adjustment work shown in FIG. 4 during the manufacturing process of the speakers 1, 101, 201, the initial positional deviation between the magnetic gap G of the magnetic circuit 10 and the voice coil 16 can be eliminated.

[0038] In ST2 of Fig. 4, the adjustment current applied to the voice coil 16 may be one in which the magnitude of the current changes over time in a sawtooth pattern or a square wave pattern. Alternatively, a positive constant current and a negative constant current may be applied. In other words, the adjustment current may include a positive current value and a negative current value.

[0039] Next, the sound generation operation of the speakers 1, 101, and 201 will be described with reference to the flow chart shown in FIG.

[0040] During sound production, a voice current is applied to the voice coil 16, and the electromagnetic force excited by the driving magnetic flux F1 and the voice current causes the diaphragm 6 to vibrate in the forward and backward directions, generating sound pressure according to the frequency of the voice current, and sound is emitted forward.

[0041] 5 is performed continuously, intermittently, or at an appropriate timing as required, while the speakers 1, 101, and 201 are producing sound. In this processing, the processing from ST12 to ST17 is repeated during the process from the start of ST11 to the completion of ST18.

[0042] In the repeated processing operation, when a trigger is received from the CPU of the control unit in ST13, the detection output from the magnetic sensor 22 is acquired in ST14. As shown in Figs. 1 and 2, the magnetic sensor 22 obtains a detection output of the horizontal component of the detection magnetic flux F2 emitted from the detection magnet 21. In ST14, the deviation amount between the assumed height position of the voice coil 16 at that time and the voice coil 16 calculated from the detection output is calculated. In ST15, if the deviation amount exceeds a threshold value, a correction signal (offset signal) for correcting the deviation amount is generated, and the correction signal is superimposed on the audio signal (voice current) in ST16.

[0043] During the sound generation operation of the speaker 1, 101, 201, if a deviation occurs in the relative position between the magnetic gap G of the magnetic circuit 10 and the voice coil 16 due to the weight of the diaphragm 6, deterioration of the edge member 7 or the damper member 8, or a change in the environmental temperature, this leads to deterioration of the sound, such as sound distortion. However, the above problem can be solved by performing feedback control using a vibration detection device 20 as shown in FIG. 5. Furthermore, as shown in FIG. 4, if an adjustment is performed at the final stage of the manufacturing process using a position adjustment mechanism 5, 40 to bring the relative position between the magnetic gap G and the voice coil 16 closer to the design value, the amount of deviation occurring in the control operation shown in FIG. 5 can be reduced. As a result, the sound quality is improved, and further, the offset signal can be reduced to suppress the generation of dark current, and the heat generation of the voice coil 16 can be suppressed. [Explanation of symbols]

[0044] 1,101,201 Speakers 2 Support 3 First support 4 Second support 5 Position adjustment mechanism 6 diaphragm 10 Magnetic Circuit 15 Bobbin 16 Voice coil 20 Vibration detection device 21 Detection magnet 22 Magnetic Sensor 30 Magnetic Circuit 32 First support 33 Second support 40 Position adjustment mechanism F1 Driving magnetic flux F2 Detection magnetic flux G Magnetic gap O center line

Claims

1. a first support supporting a magnetic circuit, a second support supporting a diaphragm, a voice coil inserted in a magnetic gap of the magnetic circuit and vibrating together with the diaphragm, a detection magnet vibrating together with the voice coil, and a magnetic sensor supported by the magnetic circuit or the first support and detecting a magnetic flux emitted from the detection magnet; A speaker is used in which the first support and the second support are connected via a position adjustment mechanism for changing a relative position in a front-rear direction along a vibration direction of the voice coil, a detection magnetic flux emitted from the detection magnet is detected by the magnetic sensor; a deviation in the relative position between the first support and the second support in the fore-aft direction is calculated; and the relative position between the first support and the second support is changed by the position adjustment mechanism in a direction that eliminates the deviation.

2. 2. The speaker adjustment method according to claim 1, wherein the adjustment current is changed with respect to time based on a trigonometric function or based on a waveform approximating a trigonometric function.

3. 3. The speaker adjustment method according to claim 1, wherein the position adjustment mechanism is a screw connection mechanism having a spiral formed about a center line that passes through the center of the first support and the second support and extends in the front-rear direction.

4. 4. The speaker adjustment method according to claim 1, wherein the position adjustment mechanism is provided at a position that is out of a magnetic flux path formed by the magnetic circuit.

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