Information
-
Patent Grant
-
6766034
-
Patent Number
6,766,034
-
Date Filed
Thursday, September 13, 200122 years ago
-
Date Issued
Tuesday, July 20, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Dennison, Schultz, Dougherty & MacDonald
-
CPC
-
US Classifications
Field of Search
US
- 381 151
- 381 152
- 381 396
- 381 401
- 381 421
- 381 431
- 340 38472
- 340 38473
- 340 4071
- 340 6935
-
International Classifications
-
-
Disclaimer
Terminal disclaimer Term Extension
306
Abstract
A speaker vibrating plate having a voice coil secured thereto is provided in a frame, a rotor having an annular side yoke is rotatably supported in the frame, and a stator having poles is provided in the frame. A first permanent magnet is provided on the rotor at a central portion thereof, and an annular second permanent magnet is mounted on the rotor outside the side yoke for forming a magnetic circuit passing through the rotor and the stator, and a stator coil is provided in the stator. A driving circuit is provided for energizing the stator coil for rotating the rotor.
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
702
. 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 the periphery
601
a
of the core
601
and the inside wall
606
a
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 rotor having an annular side yoke and rotatably supported in the frame, a stator having magnetic poles and provided in the frame, a first permanent magnet provided on the rotor for forming a gap, an annular second permanent magnet provided on the rotor outside the side yoke, a speaker vibrating plate supported in the frame, a voice coil secured to the speaker vibrating plate and inserted in the gap, at least one coil for forming magnetic fluxes between the rotor and the magnetic poles of the stator.
The rotor is rotatably mounted on the frame by a central shaft.
The device further comprises eccentric means provided on the rotor for vibrating the rotor during the rotation of the rotor.
The coil is disposed in the stator, and the first permanent magnet is an annular magnet around the shaft.
In an aspect of the invention, the eccentric means is a weight eccentrically provided in the rotor.
The device further comprises a central top yoke mounted on the first permanent magnet for forming the gap between the top yoke and the side yoke, and a driving circuit for energizing the coil for rotating the rotor.
The rotor comprises a lower rotor yoke rotatably mounted in the frame by the shaft, the side yoke secured to the lower rotor yoke, and the central top yoke, and the stator comprises a lower stator yoke and an upper stator yoke secured to the lower stator yoke.
In another aspect, the coil is disposed between the lower stator yoke and the upper stator yoke.
The rotor and the stator are formed into a synchronous motor, and the periphery of the second permanent magnet has a plurality of magnetic poles corresponding to the magnetic poles of the stator.
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 an exploded perspective view of a stator of the multifunction acoustic device of the present invention;
FIG. 5
is a driving circuit used in the multifunction acoustic device of the present invention;
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 generating device
10
, a rotor
20
and an annular stator
30
provided in a cylindrical frame
1
made of plastic. The sound generating device
10
comprises a speaker vibrating plate
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 vibrating plate
14
. The speaker vibrating plate
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 rotor
20
comprises a lower rotor yoke
23
secured to a rotor shaft
16
rotatably mounted on a base plate of the frame
1
, and an annular side yoke
22
secured to the lower rotor yoke
23
. An annular speaker permanent magnet
17
is secured to the lower rotor yoke
23
around the shaft
16
, and a central top yoke
18
is secured to the magnet
17
by the shaft
16
. The speaker permanent magnet
17
is magnetized in single-polarity in the axial direction. Thus, a first magnetic circuit is formed between the top yoke
18
and the side yoke
22
.
An annular rotor permanent magnet
21
is secured to the peripheral wall of the side yoke
22
and to the lower rotor yoke
23
. As shown in
FIG. 3
, the rotor permanent magnet
21
is magnetized in multiple-polarity in the radial direction, so that the peripheral wall of the rotor permanent magnet has a plurality of magnetic poles. Thus, a second magnetic circuit is formed between the rotor
20
and the stator
30
. The voice coil
15
is disposed in a speaker gap
11
formed between the outside wall of the top yoke
18
and the inside wall of the side yoke
22
.
As shown in
FIGS. 2 and 3
, a semicircular weight
24
made of plastic including heavy particles such as tungsten particles is secured to the outside wall of the side yoke
22
and mounted on the rotor permanent magnet
21
. As another means, the permanent magnet
21
may be eccentrically disposed with respect to the rotor shaft
16
. A motor gap
12
is formed between the periphery of the rotor permanent magnet
21
and the inside wall of the stator
30
. As shown in
FIGS. 1 and 2
, the annular stator
30
is disposed around the rotor
20
.
Referring to
FIG. 4
, the stator
30
comprises an annular stator coil
33
, annular upper and lower shading plates
36
and
35
disposed on the upper and lower sides of the annular coil
33
, and annular upper and lower stator yokes
31
and
32
. The upper stator yoke
31
has four main magnetic poles
31
a
1
,
31
b
1
,
31
c
1
and
31
d
1
, and four auxiliary magnetic poles
31
a
2
,
31
b
2
,
31
c
2
and
31
d
2
. Each of the magnetic poles extends in the axial direction and toward the lower stator yoke
32
. The lower stator yoke
32
has four main magnetic poles
32
a
1
,
32
b
1
,
32
c
1
and
32
d
1
and four auxiliary magnetic poles
32
a
2
,
32
b
2
,
32
c
2
and
32
d
2
.
A couple of upper main and auxiliary magnetic poles
31
a
1
and
31
a
2
and a couple of lower main and auxiliary magnetic poles
32
a
1
and
32
a
2
, and other couples of the magnetic poles are angularly disposed at one magnetic pole pitch of 90 degrees (electric angle 360°). The sum of widths of the main magnetic pole and the auxiliary magnetic pole is within 45 degrees, and the width of the main magnetic pole is larger than that of the auxiliary magnetic pole.
The couple of upper main and auxiliary magnetic poles and the couple of lower main and auxiliary magnetic poles are alternately disposed on the same circle as shown in FIG.
2
.
The upper shading plate
36
has four holes
36
a
,
36
b
,
36
c
and
36
d
, each formed in a projection projected from the inside wall of the shading plate
36
in the radially inward direction. Similarly, the lower shading plate
35
has four holes
35
a
,
35
b
,
35
c
and
35
d
. The auxiliary magnetic poles
31
a
2
,
31
b
2
,
31
c
2
and
31
d
2
of the upper stator yoke
31
are inserted in the holes
36
a
-
36
d
of the upper shading plate
36
. Similarly, the auxiliary magnetic poles
32
a
2
,
32
b
2
,
32
c
2
and
32
d
2
of the lower stator yoke
32
are inserted in the holes
35
a
-
35
d
of the lower shading plate
35
.
Referring to
FIGS. 1 and 4
, the lower stator yoke
32
has a cylindrical peripheral wall
32
e
. The lower shading plate
35
is mounted on the lower stator yoke
32
between the peripheral wall
32
e
and main and auxiliary magnetic poles. The stator coil
33
, upper shading plate
36
, and upper stator plate
31
are stacked on the lower shading plate
35
in order. Thus, the rotor
20
and stator
30
are composed in a synchronous motor.
It will be understood that the motor can be made into a stepping motor having a permanent magnet rotor having multiple polarities.
The magnetomotive force of the permanent magnet
21
is applied to the speaker and motor gaps
11
and
12
in parallel, so that a necessary magnetic flux density is provided.
Referring to
FIG. 5
, a rotor driving circuit
40
comprises a pair of NPN transistors
41
and
43
and a pair of PNP transistors
42
and
44
which are connected crosswise, interposing the stator coil
33
. Bases of the transistors
41
and
42
are connected to an input terminal
48
, bases of the transistors
43
and
44
are connected to the input terminal
48
through an inverter
47
.
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 vibrating plate
14
is vibrated in the Y direction (
FIG. 1
) to generate sounds.
When a low frequency signal of about 100-300 Hz is applied to input terminal
48
of the driving circuit
40
, the transistors
41
and
44
are turned on at a high level of the input signal. Consequently, a current passes the stator coil
33
through the transistors
41
and
44
from the Vcc to GND. And the current passes through the transistor
43
, coil
33
and transistor
42
at a low level of the input signal. Thus, an alternate current of the low frequency corresponding to the input low frequency signal flows in the stator coil
33
. Consequently, couples of main pole
32
a
1
and auxiliary pole
32
a
2
to poles
32
d
1
and
32
d
2
are energized. At that time, magnetic flux generated by four auxiliary poles
31
a
2
,
31
b
2
,
31
c
2
and
31
d
2
, and magnetic flux generated by four auxiliary poles
32
a
2
,
32
b
2
,
32
c
2
and
32
d
2
are delayed in phase by eddy currents passing through holes
36
a
-
36
d
of the upper shading plate
36
and holes
35
a
-
35
d
of the lower shading plate
35
to produce a shifting magnetic field to generate rotating power in a predetermined direction. Thus, the rotor
20
is rotated at the driving low frequency. Since the weight
24
is eccentrically mounted on the rotor
20
, 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 number N of rotation of the rotor is expressed as follows.
N
=60
f/Z
(rpm) 1
where Z is a pair of number of poles of the rotor,
f is driving frequency.
The load torque TL is expressed as follows.
TL=μrRω
2
M
(
N·m
) 2
where M is the mass of weight
24
of the rotor,
R is the length between the center of the rotor shaft
16
and the center of gravity of the weight
24
,
r is the radius of the rotor shaft
16
,
μ is the friction coefficient between the rotor shaft
16
and the rotor
20
,
ω is the number of rotation (rad/sec) of the rotor
20
.
Since the rotor
20
merely bears the load torque TL, the power consumption of the device is small.
If a lower frequency signal is applied to the input terminal
48
to rotate the rotor
20
during the generating sounds by the speaker vibrating plate
14
, the magnetic flux density in the first gap
11
does not change from the magnetic flux density when only the speaker vibrating plate
14
is vibrated. Therefore, quality of sounds generated by the vibrating plate does not reduce even if the rotor
20
rotates.
Although the synchronous motor is used in the above described embodiments, other motors such as a stepping motor, a direct current motor and others can be used. Further, the rotor can be disposed outside the stator.
From the foregoing description, it will be understood that the present invention provides a multifunction acoustic device which may generate sounds and vibration of the frame at the same time without reducing sound quality. In the prior art, since the speaker vibrating plate 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 rotor having an annular side yoke and rotatably supported in the frame; a stator having magnetic poles and provided in the frame; a first permanent magnet provided on the rotor for forming a gap; an annular second permanent magnet provided on the rotor outside the side yoke; a speaker vibrating plate supported in the frame; a voice coil secured to the speaker vibrating plate and inserted in the gap; at least one coil for forming magnetic fluxes between the rotor and the magnetic poles of the stator.
- 2. The device according to claim 1 wherein the rotor is rotatably mounted on the frame by a central shaft.
- 3. The device according to claim 1 further comprising eccentric means provided on the rotor for vibrating the rotor during the rotation of the rotor.
- 4. The device according to claim 1 wherein the coil is disposed in the stator.
- 5. The device according to claim 2 wherein the first permanent magnet is an annular magnet around the shaft.
- 6. The device according to claim 3 wherein the eccentric means is a weight eccentrically provided in the rotor.
- 7. The device according to claim 5 further comprising a central top yoke mounted on the first permanent magnet for forming the gap between the top yoke and the side yoke.
- 8. The device according to claim 7 further comprising a driving circuit for energizing the coil for rotating the rotor.
- 9. The device according to claim 8 wherein the rotor comprises a lower rotor yoke rotatably mounted in the frame by the shaft, the side yoke secured to the lower rotor yoke, and the central top yoke, and the stator comprises a lower stator yoke and an upper stator yoke secured to the lower stator yoke.
- 10. The device according to claim 9 wherein the coil is disposed between the lower stator yoke and the upper stator yoke.
- 11. The device according to claim 10 wherein the rotor and the stator are formed into a synchronous motor.
- 12. The device according to claim 10 wherein the periphery of the second permanent magnet has a plurality of magnetic poles corresponding to the magnetic poles of the stator.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-286414 |
Sep 2000 |
JP |
|
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
6611605 |
Kim |
Aug 2003 |
B2 |
6621911 |
Kobayashi et al. |
Sep 2003 |
B2 |