JP2002248427A - Multifunctional speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin multifunctional speaker produced by improving a conventional rotation type multifunctional speaker, excellent in sound reproduction with a high sound quality, and added with some advantageous points such that the speaker is miniaturized to save a space, can precisely be assembled, or excellent in magnetic characteristics. SOLUTION: The multifunctional speaker comprises as a rotor, a magnetic circuit provided with a cylindrical voice coil fixed in a diaphragm for voice sound and a cylindrical space into which the voice coil is inserted and the rotor further comprises an eccentric weight member and a magnetic pole in the outer circumferential part for driving the rotor. A stator is installed in the outside of the rotor and a portion of a frame for holding the stator and the rotary shaft of the rotor is made to form a portion of the magnetic member composing the magnetic circuit. A ring-like portion raised from the circumference rim part of the frame is in particular, made to form a main portion of the magnetic member composing the magnetic circuit of the stator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multifunctional sounding body capable of generating an acoustic frequency output and a low frequency vibration output with a single device.

[0002]

2. Description of the Related Art For example, in a portable telephone, two types of electro-mechanical converters are required: a speaker for voice and a generator of low-frequency vibration that can be felt silently to notify incoming calls. Therefore, proposals have been made to integrate these two types of converters integrally to reduce the size, weight, and cost of devices such as mobile phones. Hereinafter, the structure of a conventional example of the multifunctional sounding body (referred to as such since a single device can output a signal of a plurality of kinds of frequencies including an audio signal) will be described. This is described, for example, in JP-A-5-85192.

In this conventional example, the electromechanical transducer for voice almost follows the structure of a normal dynamic speaker. That is, a thin cylindrical voice coil fixed to the voice diaphragm is inserted into the cylindrical gap of the magnetic circuit. When a voice current is passed through the voice coil, the diaphragm vibrates in the axial direction at the voice frequency. Generates sound. On the other hand, a magnetic circuit having a considerable mass is suspended from a frame by a leaf spring or the like so that it can be displaced in the axial direction.
A low frequency natural frequency of about 0 Hz is given. Therefore, when a low-frequency drive current that is close to the natural frequency is applied to the voice coil, the voice diaphragm does not vibrate much because the natural frequency is far apart, and the magnetic circuit resonates and vibrates with a large amplitude. I do. The reaction of the vibration of the large-mass magnetic circuit gives a vibrating vibration to a mobile phone or the like.

[0004]

However, in the prior art, the magnetic circuit is suspended by a spring and can be displaced in the same vibration direction (axial direction of the voice coil) as the voice coil. In response, the sound diaphragm does not vibrate according to the sound signal faithfully. That is, it is inevitable that the sound reproduction quality is somewhat deteriorated.
In particular, when an audio signal and a low-frequency signal are superimposed and input to the voice coil, the magnetic circuit drives the voice coil while being displaced at a low frequency, so that the audio output is further disturbed, and sound reproduction is practically impossible. Another problem of the conventional example is that the thickness of the transducer is likely to be large because two types of vibration mechanisms in the same direction are overlapped.

[0005] In order to solve these problems, the present applicant has already proposed, in Japanese Patent Application No. 2000-286414, a configuration of a novel multifunctional sounding body which is believed not to be known yet. The magnetic circuit cannot move in the axial direction, but it can be rotated around the central axis of the sounding body (the central axis of the voice coil), and the eccentric weight is mounted on the rotor, which is fixed outside. The rotor is driven to rotate in the same manner as a motor, and an exciting force that is a low-frequency output that can be sensed by a centrifugal force that changes its direction due to the rotation of the eccentric weight is obtained. FIG. 2 shows a sectional view of the structure.

The main part of the sounding body shown in FIG. 2 is rotationally symmetric with respect to the center axis included in the cross section. In FIG. 2, frame 1
Is made of synthetic resin or metal and has a shallow cylindrical shape with a bottom,
A sound emitting cover 2 having a large number of sound emitting holes is fixed to the upper end surface of the peripheral cylindrical portion 1a at the peripheral edge, and a cylindrical voice coil 3 is fixed to the lower surface of the stepped portion 1b which goes around the upper end. The peripheral portion of the thin disk-shaped sound diaphragm 4 having the unevenness is adhered and held. (These are bonded at the final stage of assembly.) The structure and operation of this sounding body (multifunctional acoustic device) are described in the above-mentioned Japanese Patent Application No. 2000-2.
No. 86414.

A rotor shaft 5 is implanted at the center of the bottom plate 1c of the frame 1. Reference numeral 6 denotes a rotor. A cup-shaped yoke 7 made of a soft magnetic material, a ring-shaped voice permanent magnet 8 magnetized in the axial direction, and a top yoke 9 made of a soft magnetic material are press-fitted into a sleeve 10. A permanent magnet 11 for the motor (which is magnetized so that one or more pairs of N and S poles alternately appear at equal intervals on the outer cylindrical surface) is fitted and fixed to the outer peripheral portion of the cup-shaped yoke 7. And an eccentric weight 12 that generates a centrifugal force as an exciting force by the rotation of the rotor 6.
(Having a semicircular annular shape).

The sleeve 10 is rotatably mounted on the rotor shaft 5 with the washer 13 as a spacer, and is stopped by a stop ring 14. Since the voice coil 3 is concentrically inserted into the magnetic field of the cylindrical audio gap formed by the inner peripheral upper end of the cup-shaped yoke 7 and the outer peripheral side surface of the top yoke 9, an audio current flows through the voice coil 3. Like the ordinary speaker, the sound diaphragm 4 vibrates in the axial direction of the sounding body and emits sound output regardless of the presence or absence of rotation of the rotor 6.

Reference numeral 15 denotes a stator, which is disposed so as to surround the outer periphery of the rotor 6. This is a stator coil 16 wound in a cylindrical shape, and a stator upper yoke 17 arranged on each of the upper and lower surfaces thereof.
And a ring-shaped yoke 19 connecting their outer peripheral parts to form a magnetic circuit so as to surround the cross section of the stator lower yoke 18 and the stator coil 16. The stator upper yoke 17 and the stator lower yoke 18 have the same number of toothed magnetic pole pieces 17a and 18a (not shown in the form of a flat surface) which are bent to form a stator coil. The permanent magnets 11 for motors are alternately arranged in contact with the inner cylindrical surface of the motor 16 and are separated by a motor gap 20.
And the outer peripheral surface of When a low frequency oscillating current is applied to the stator coil 16, the magnetic poles appear to rotate on the magnetic pole pieces 17a and 18a, and the magnetic poles and the motor permanent magnet 1
Rotation is given to the rotor 6 by suction and repulsion of the N and S poles appearing on the outer cylindrical surface of the rotor 1.

In this structure, the stator 15 previously assembled is inserted into the cylindrical portion of the frame 1 from above to position the stator. With this configuration, the intended purpose of obtaining an exciting force that does not affect the sound output is sufficiently achieved, but there are some problems as described below. That is, (1) The magnetic circuit of the stator cannot be further reduced in size. Alternatively, the degree of freedom in design is limited, and there is no space for adding additional functions. (2) It is difficult to obtain sufficiently high precision in positioning the stator. (3) Since the magnetic circuit of the stator is formed by coupling the individual components of the ring-shaped yoke, the stator upper yoke, and the stator lower yoke, the magnetic resistance at the joint thereof is large, causing magnetic flux leakage. The efficiency of the motor is likely to be poor.

SUMMARY OF THE INVENTION An object of the present invention is to further improve the basic structure of the rotary multi-function sounding body which has already been proposed, so that the sound reproducing quality is excellent irrespective of driving conditions and the structure is made thin. In addition to the features of the basic structure that can be used, it is possible to further reduce the size or create a configuration that allows more space, easily improve assembly accuracy, and have excellent magnetic characteristics Is to provide the body.

[0012]

In order to achieve the above object, a multifunctional sounding body according to the present invention has the following features. (1) A rotor is a magnetic circuit having a cylindrical voice coil fixed to an audio diaphragm and a cylindrical gap into which the voice coil is inserted, and the rotor further includes an eccentric weight member and an outer peripheral portion. A magnetic pole for driving the rotor is provided, and a stator is disposed outside the rotor, and a part of a frame that holds the stator and a rotation axis of the rotor is a magnetic pole of the stator. It also serves as a part of the magnetic member that constitutes the circuit.

The multifunctional sounding body of the present invention may further have the following features. (2) The frame has a substantially flat portion and a cylindrical portion rising from a peripheral edge of the frame, and the cylindrical portion is a main magnetic member constituting the magnetic circuit of the stator. That also serves as a part of

[0014]

FIG. 1 is a cross-sectional view showing the structure of an improved multifunctional sounding body according to an embodiment of the present invention. The configuration of this example is different from the configuration before improvement shown in FIG.
It is basically the same except that the parts related to the frame and the stator are different. Therefore, the reference numerals assigned to FIG. 1 are the same as those in FIG. 2, and the portions having substantially the same configuration will not be described repeatedly, and only the essential differences will be described below.

In FIG. 1, a soft magnetic material is used for the material of the frame 1. That is, a resin material mixed with a soft magnetic metal powder is subjected to insert mold injection molding. Alternatively, a metal material such as permalloy or pure iron is formed into a cup shape by plastic working, and this molded product is subjected to insert molding injection molding with a resin material. Instead of using the ring-shaped yoke 19, a part of the cylindrical portion 1b of the frame 1 can function as a part of the magnetic circuit of the stator 15 instead of the ring-shaped yoke. As shown, the stator upper yoke 17 has its outer side surface in contact with the inner side surface of the frame cylindrical portion 1a in the same manner as the ring yoke in the old structure.

Since the lower surface of the lower stator yoke 18 is in contact with the upper surface of the bottom plate 1c of the frame 1, which is also a magnetic material, over a large area, the magnetic resistance of the magnetic flux flowing from the lower stator yoke 18 to the bottom plate 1c is small. . Further, since the bottom plate 1c and the cylindrical portion 1b are integrated, there is almost no magnetic resistance between them. Therefore, the stator upper yoke 17 and the stator lower yoke 1
Compared with the old structure having many end face connection portions of the respective plate members of the ring 8 and the ring-shaped yoke 19, there is an advantage that the magnetic resistance of the magnetic circuit surrounding the cross section of the stator coil 16 in the structure of the present example can be clearly reduced. is there.

The pole pieces 17a, 1
Stator upper yoke 17 having stator 8a and stator lower yoke 18
Are directly positioned by the inner wall of the cylindrical portion 1a of the frame 1. Therefore, the positional relationship between the rotor shaft 5 implanted on the bottom plate 1c and the motor permanent magnets 11a
Of the motor gap 20, that is, the accuracy of the motor gap 20, can be easily improved.

In this embodiment, since the ring-shaped yoke 19 is not required, it cannot be overemphasized that the diameter of the sounding body can be reduced to approximately twice the thickness. This makes it possible to reduce the size of the sounding body, or the extra space obtained by the reduction can be diverted for other purposes. Although not shown, for example, the voice coil 5
Or to allow room for the arrangement of the terminal group for the stator coil 16.

Although an example of the embodiment of the present invention has been described above, the present invention can be embodied in other forms. In particular, various changes can be made to the details. For example, the shape of the contact portion between the stator upper yoke 17 and the cylindrical portion 1a may be devised to make the surface contact so that the magnetic resistance of the stator magnetic circuit can be further reduced. The bottom plate 1c can also be used in various ways. There are various other changes.

[0020]

According to the present invention, since a part of the frame of the multifunctional sounding body is also used for the stator magnetic circuit, there is an effect that the sounding body can be miniaturized and the surplus space can be utilized. In this case, it is easy to improve the magnetic characteristics of the stator magnetic circuit and the positioning accuracy of the main parts such as the pole pieces of the stator. Particularly, when a cylindrical portion of the frame is used as a stator magnetic circuit, a remarkable effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure of an improved multifunctional sounding body, which is an example of an embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of an example of a multifunctional sounding body before improvement.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 1a Cylindrical part 1b Step part 1c Bottom plate 2 Sound emission cover 3 Voice coil 4 Sound diaphragm 5 Rotor shaft 6 Rotor 7 Cup type yoke 8 Permanent magnet for sound 9 Top yoke 10 Sleeve 11 Motor permanent magnet 12 Eccentric weight 13 Washer 14 Stop ring 15 Stator 16 Stator coil 17 Stator upper yoke 18 Stator lower yoke 17a, 18a Magnetic pole piece 19 Ring-shaped yoke 20 Motor gap

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D012 BA06 BB02 GA04 5D017 AA11 5D107 AA12 AA13 AA14 AA16 BB08 CC09 DD09 FF07

Claims (2)

[Claims] A rotor is a magnetic circuit having a cylindrical voice coil fixed to an audio diaphragm and a cylindrical gap into which the voice coil is inserted. The rotor further includes an eccentric weight member and an outer peripheral portion. A magnetic pole for driving the rotor, and a stator disposed outside the rotor, and a part of a frame holding the stator and a rotation axis of the rotor is the stator. A multi-function sounding body, which also serves as a part of a magnetic member constituting the magnetic circuit of (1). 2. The shape of the frame includes a substantially flat plate-like portion and a cylindrical portion rising from a peripheral portion of the frame, and the cylindrical portion mainly constitutes the magnetic circuit of the stator. A multifunctional sounding body characterized in that it also serves as a part of a magnetic member.