Information
-
Patent Grant
-
6639992
-
Patent Number
6,639,992
-
Date Filed
Monday, November 19, 200122 years ago
-
Date Issued
Tuesday, October 28, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Dennison, Schultz & Dougherty
-
CPC
-
US Classifications
Field of Search
US
- 381 396
- 381 412
- 381 414
- 381 418
- 381 162
- 381 165
- 381 417
- 335 302
- 335 306
- 310 15401
- 310 15402
- 310 15403
- 310 15404
- 310 15405
- 310 15406
- 310 264
- 310 27
- 340 758
- 340 762
- 340 763
- 340 4071
- 340 6935
-
International Classifications
-
Abstract
A speaker diaphragm is supported in a frame and a voice coil is secured to the speaker diaphragm. A rotor having a central permanent magnet and a cylindrical hub provided around the central permanent magnet is rotatably supported in the frame. A motor annular permanent magnet is disposed around the rotor. The voice coil is disposed in the gap formed between the central permanent magnet and the hub.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a multifunction acoustic device used in a portable instrument such as a portable telephone.
There has been provided an acoustic device of the portable instrument in which a speaker is provided for generating sounds of calling signals, and a vibrating motor is provided for informing the receiver of calling signals without generating sounds. In such a device, since both of the speaker and the motor are mounted in the device, the device is increased in size and weight, and in manufacturing cost.
In recent years, there is provided a multifunction acoustic device in order to remove the above described disadvantages. The multifunction acoustic device comprises a speaker having a vibrating plate and a permanent magnet magnetically connected to a voice coil mounted on the vibrating plate of the speaker. The permanent magnet is independently vibrated at a low frequency of 100-150 Hz so as to inform the receiving of calling signals by the vibration of the case of the device, which is transmitted to the body of the user of the device.
FIG. 6
is a sectional view of a conventional electromagnetic induction converter disclosed in Japanese Patent Laid Open 5-85192. The converter comprises a diaphragm
506
mounted in a case
512
at a periphery thereof, a voice coil
508
secured to the underside of a central portion
507
of the diaphragm
506
, a spring plate
511
mounted in the case
512
, and a permanent magnet
510
secured to a central portion of the spring plate
511
, inserted in the voice coil
508
.
By applying a low or high frequency signal to the voice coil
508
, the spring plate
511
is vibrated in the polarity direction Y of the magnet
510
.
In the device, the diaphragm
506
and the spring plate
511
are relatively moved through the magnetic combination between the voice coil
508
and the magnet
510
. Consequently, when a low frequency signal or a high frequency signal is applied to the voice coil
508
, both of the diaphragm
506
and the spring plate
511
are sequentially vibrated. As a result, sounds such as voice, music and others generated from the device are distorted, thereby reducing the quality of the sound. In addition, vibrating both of the voice coil
508
and the magnet
510
causes the low frequency vibration of the magnet to superimpose on the magnetic combination of the voice coil
508
and the magnet
510
, which further largely distorts the sounds.
FIG. 7
is a sectional view showing a conventional multifunction acoustic device. The device comprises a speaker vibrating plate
603
made of plastic and having a corrugated periphery
603
a
and a central dome, a voice coil
604
secured to the underside of the vibrating plate
603
at a central portion, and a magnet composition
610
. The vibrating plate
603
is secured to a frame
609
with adhesives.
The magnetic composition
610
comprises a lower yoke
605
, a core
601
formed on the yoke
605
at a central portion thereof, an annular permanent magnet
602
mounted on the lower yoke
605
, and an annular upper yoke
606
mounted on the permanent magnet
602
. The lower yoke
605
and the upper yoke
606
are resiliently supported in the frame
609
by spring plates
607
and
608
. A magnetic gap
611
is formed between a periphery
601
a
of the core
601
and an inside wall
606
a
of the upper yoke
606
to be magnetically connected to the voice coil
604
.
When an alternating voltage is applied to the voice coil
604
through input terminals
612
a
and
612
b
, the speaker vibrating plate
603
is vibrated in the direction Y to generate sounds at a frequency between 700 Hz and 5 KHz. If a low frequency signal or a high frequency signal is applied to the voice coil
604
, the speaker vibrating plate
603
and the magnetic composition
610
are sequentially vibrated, since the magnetic composition
610
and the speaker vibrating plate
603
are relatively moved through the magnetic combination of the voice coil
604
and the magnet composition
610
.
As a result, sounds such as voice, music and others generated from the device are distorted, thereby reducing the quality of the sound. In addition, the driving of both the voice coil
604
and the magnetic composition
610
causes the low frequency vibration to superimpose on the magnetic combination of the voice coil
604
and the magnetic composition
610
, which further largely distorts the sounds.
FIG. 8
is a sectional view showing another conventional multifunction acoustic device. The device comprises the speaker vibrating plate
603
made of plastic and having the corrugated periphery
603
a
and the central dome, the voice coil
604
secured to the underside of the vibrating plate
603
at a central portion, and the magnet composition
610
. The vibrating plate
603
is secured to the frame
609
with adhesives.
The magnetic composition
610
comprises a lower yoke
703
, core
601
formed on the yoke
703
at a central portion thereof, an annular permanent magnet
702
secured to the lower yoke
703
, and annular upper yoke
606
having a peripheral wall
606
b
and mounted on the permanent magnet
602
. The upper yoke
606
is resiliently supported in the frame
609
by spring plates
707
and
708
. A first magnetic gap
701
is formed between a periphery
601
a
of the core
601
and an inside wall of the upper yoke
606
to be magnetically connected to the voice coil
604
. A second gap
705
is formed between a periphery
703
a
of the lower yoke
703
and inside wall
606
a
of the upper yoke
606
. A driving coil
706
is secured to the frame and inserted in the second gap
705
.
When an alternating voltage is applied to the voice coil
604
through input terminals
612
a
and
612
b
, the speaker vibrating plate
603
is vibrated in the direction Y to generate sounds at a frequency between 700 Hz and 5 KHz. If a low frequency signal or a high frequency signal is applied to the voice coil
604
, the speaker vibrating plate
603
and the magnetic composition
610
are sequentially vibrated, since the magnetic composition
610
and the speaker vibrating plate
603
are relatively moved through the magnetic combination of the voice coil
604
and the magnet composition
610
.
When a high frequency signal for music is applied to the voice coil
604
, only the speaker vibrating plate
603
is vibrated. Therefore, there does not occur distortion of the sound. Furthermore, when a low frequency signal is applied to the driving coil
706
, only the magnetic composition
610
is vibrated, and the speaker vibrating plate
603
is not vibrated.
However if a high frequency signal is applied to input terminals
612
a
,
612
b
, and a low frequency signal is also applied to input terminals
704
a
,
704
b
, the speaker vibrating plate
603
and magnetic composition
610
are sequentially vibrated, thereby reducing the sound quality.
In the above described conventional devices, both the speaker vibration plate and the magnetic composition are vibrated when a low frequency signal or a high frequency signal is applied to the voice coil. This is caused by the reason that the low frequency vibrating composition is vibrated in the same direction as the high frequency vibrating direction.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a multifunction acoustic device in which a vibrating member is not vibrated together with another vibrating member, thereby removing disadvantages of conventional devices.
According to the present invention, there is provided a multifunction acoustic device comprising a frame, a speaker diaphragm supported in the frame, a voice coil secured to the speaker diaphragm, a rotor having a central permanent magnet and a cylindrical hub provided around the central permanent magnet, and rotatably supported in the frame, a motor annular permanent magnet disposed around the rotor, the voice coil being disposed in the gap formed between the central permanent magnet and the hub.
The rotor comprises an armature and a commutator.
The device further comprises a weight eccentrically provided on the rotor.
The armature comprises cores secured to the hub, and coils mounted on the cores, and the commutator comprises segments and a pair of brushes for applying a current to the coils through the segments.
These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1
is a sectional view of a multifunction acoustic device of the present invention;
FIG. 2
is a sectional view taken along a line II—II of
FIG. 1
;
FIG. 3
is an exploded perspective view of a rotor of the multifunction acoustic device of the present invention;
FIG. 4
is a plan view of the underside of a commutator of the multifunction acoustic device of the present invention;
FIG. 5
is a perspective view of the commutator of
FIG. 4
;
FIG. 6
is a sectional view of a conventional electromagnetic induction converter;
FIG. 7
is a sectional view showing a conventional multifunction acoustic device; and
FIG. 8
is a sectional view showing another conventional multifunction acoustic device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to
FIGS. 1 and 2
, the multifunction acoustic device of the present invention comprises a sound producing device
10
, and a direct current motor
20
provided in a cylindrical frame
1
made of plastic or magnetic material. The sound producing device
10
comprises a speaker diaphragm
14
having a central dome
14
a
and secured to the frame at a periphery
14
b
with adhesives, a voice coil
15
secured to the underside of the speaker diaphragm
14
. The speaker diaphragm
14
is covered by a cover
13
having a plurality of sound discharge holes and secured to the frame
1
at a peripheral edge thereof.
The direct current motor
20
has a hub
23
having a flat cup shape and made of magnetic material which also acts a role of a yoke for the sound producing device
10
. The hub
23
is secured to a shaft
16
which is rotatably mounted on a base plate of the frame
1
.
On the bottom of the hub
23
, a cylindrical speaker central permanent magnet
21
and a top plate
18
made of magnetic material are stacked around the shaft
16
and secured to each other by a large diameter flange
16
a
of the shaft
16
. The permanent magnet
21
is magnetized in the axial direction. The voice coil
15
is disposed in a magnetic gap
24
between the peripheral inside wall of the hub
23
and the peripheral wall of the top plate
18
.
The direct current motor
20
further comprises a rotor
25
comprising an armature, a commutator
26
, and a motor annular permanent magnet
27
. As shown in
FIGS. 2 and 3
, the rotor
25
has three cores
28
,
29
and
30
formed around a central ring
31
as shown in
FIGS. 2 and 3
. On the cores
28
,
29
and
30
, armature coil
28
a
,
29
a
and
30
a
are attached. A pair of eccentric weights
33
are secured to the cores
29
and
30
. The central ring
31
is secured to the hub
23
.
A commutator holding frame
35
made of plastic and having a disk shape is secured to the peripheral wall of the hub
23
.
As shown in
FIGS. 4 and 5
, three commutator segments
36
,
37
and
38
are formed on the underside of the commutator holding frame
35
by metal plating.
Both ends of each of the armature coils
28
a
,
29
a
and
30
a
are connected to adjacent commutator segments by a terminal
32
at the peripheral walls of the segments. For example, both ends
30
b
and
30
c
of the coil
30
a
are connected to terminals
32
of adjacent segments
36
and
37
as shown in
FIGS. 2
,
4
and
5
.
As shown in
FIGS. 4 and 5
, a pair of brushes
40
are provided so that an inner end portion of each brush contacts with segments
36
,
37
,
38
when rotating. A base portion of the brush
40
is secured to the frame
1
by adhesive. In the case of metallic frame, the base portion is secured to the frame, interposing an insulator. The base of the brush is projected from the frame
1
and connected to a direct current source (not shown).
The motor permanent magnet
27
is magnetized in radial directions at plural poles.
In operation, when a high frequency signal is applied to input terminals
19
a
and
19
b
(
FIG. 1
) of the voice coil
15
, the speaker diaphragm
14
is vibrated in the Y direction (
FIG. 1
) to produce sounds.
When a direct current is applied to the coils
28
a
,
29
a
and
30
a
through the brushes
40
, driving torque between the cores
28
to
30
and the permanent magnet
27
generates. Thus, the rotor
25
rotates. Since the weights
33
are eccentrically mounted on the rotor
25
, the rotor vibrates in radial direction. The vibration is transmitted to user's body through the frame
1
and a case of the device so that a calling signal is informed to the user.
The load torque TL is expressed as follows.
TL=μrRω
2
M
(
N·m
)
where
M is the mass of weights
33
of the rotor,
R is the length between the center of the rotor shaft
16
and the center of gravity of the weights
33
,
r is the radius of the rotor shaft
16
,
μ is the friction coefficient between the rotor shaft
16
and the rotor
25
,
ω is the number of rotation (rad/sec) of the rotor
20
.
Since the rotor
25
merely bears the load torque TL, the power consumption of the device is small.
If a lower frequency signal is applied to the brushes
40
to rotate the rotor
25
during the generating sounds by the speaker diaphragm
14
, the magnetic flux density in the gap
24
does not change from the magnetic flux density when only the speaker diaphragm
14
is vibrated.
From the foregoing description, it will be understood that the present invention provides a multifunction acoustic device which may produce sounds and vibration of the frame at the same time without reducing sound quality. In the prior art, since the speaker diaphragm and the magnetic composition are vibrated in the same direction, the thickness of the device increases. In the device of the present invention, since the magnetic composition rotates, the thickness of the device can be reduced.
While the invention has been described in conjunction with preferred specific embodiment thereof, it will be understood that this description is intended to illustrate and not limit the scope of the invention, which is defined by the following claims.
Claims
- 1. A multifunction acoustic device comprising:a frame; a speaker diaphragm supported in the frame; a voice coil secured to the speaker diaphragm; a rotor having a central permanent magnet and a cylindrical hub provided around the central permanent magnet, and rotatably supported in the frame; a motor annular permanent magnet disposed around the rotor; the voice coil being disposed in the gap formed between the central permanent magnet and the hub.
- 2. The device according to claim 1 wherein the rotor comprises an armature and a commutator.
- 3. The device according to claim 2 wherein the armature comprises cores secured to the hub, and coils mounted on the cores, and the commutator comprises segments and a pair of brushes for applying a current to the coils through the segments.
- 4. The device according to claim 1 further comprising eccentric means provided on the rotor for vibrating the rotor during the rotation of the rotor.
- 5. The device according to claim 4 wherein the eccentric means is a weight eccentrically provided on the rotor.
- 6. The device according to claim 1 wherein the central permanent magnet is an annular magnet.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-358565 |
Nov 2000 |
JP |
|
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4931765 |
Rollins et al. |
Jun 1990 |
A |
5802189 |
Blodget |
Sep 1998 |
A |