Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2002-01-07
2004-11-16
Tugbang, A. Dexter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S592100, C029S609100, C381S113000, C381S116000, C381S174000, C381S191000
Reexamination Certificate
active
06817084
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a speaker apparatus and a manufacturing method thereof.
2. Discussion of the Related Art
In a speaker apparatus for converting electric signals to acoustic energy, a so called electrokinetic cone type speaker unit has conventionally been used.
FIG. 11
shows an example of such a speaker unit. Referring to
FIG. 11
, a cylindrical voice coil bobbin
103
, around which voice coil
102
is wound, is provided at the center of a diaphragm
101
(cone) of the cone type speaker unit.
The diaphragm
101
and the voice coil bobbin
103
are fixed to one end of a ring-shaped edge
108
and a damper
109
having appropriate compliance and stiffness. The other ends of the edge
108
and damper
109
are fixed to a frame
112
equipped with a magnetic circuit
107
, so that the frame
112
elastically supports the diaphragm
101
and voice coil bobbin
103
.
The edge
108
and damper
109
support the voice coil
102
and voice coil bobbin
103
at respective predetermined positions in a magnetic gap of the magnetic circuit
107
, which is constituted of a magnet
104
, a plate
105
, a pole yoke
106
, and the like. With this structure, the diaphragm
101
is elastically supported without contacting the magnetic circuit
107
so as to be capable of vibrating like a piston in a predetermined direction within a predetermined amplitude range.
The leads of the voice coil
102
are connected to the respective ends of a pair of conductive lead wires
111
. The other ends of the paired lead wires
111
are connected to a pair of terminals
110
provided on the frame
112
.
Thus, when an electric current carrying acoustic signals is supplied from the terminals
110
to the voice coil
102
through the lead wires
111
, the voice coil
102
is driven in the magnetic gap of the magnetic circuit
107
along the piston vibration direction of the diaphragm
101
. As a result, the diaphragm
101
vibrates together with the voice coil
102
and voice coil bobbin
103
, and converts the electric signals to acoustic energy, thereby producing acoustic waves.
A center cap
113
is fixed on the diaphragm
101
to cover a center hole at the center of the diaphragm
101
, and moves integrally with the diaphragm
101
. With this structure, the structural strength between the diaphragm
101
and voice coil
102
is intensified, thereby minimizing undesirable separate vibrations of diaphragm
101
and voice coil
102
.
Further, because the center cap
113
vibrates integrally with the diaphragm
101
, the center cap
113
also contributes to the generation of acoustic radiation power (mainly high frequency range) and also to phase correction of acoustic wave interference due to the shape of the diaphragm
101
by changing acoustic characteristics. Thus, the influences of the center hole of the diaphragm
101
on the acoustic characteristics can be corrected as desired.
The conventional electrokinetic cone speaker unit is constructed in the above manner and is manufactured by the manufacturing method shown in
FIGS. 12A-12C
and
13
A-
13
D.
FIGS. 13A-13D
show the manufacturing steps of the cone type speaker unit of FIG.
11
.
FIGS. 12A-12C
show a preparatory process therefor.
First, the preparatory process will be described with reference to
FIGS. 12A-12C
.
FIG. 12A
is a cross-sectional view showing a structure of a coil gauge
114
with the preparatory process in which the coil gauge
114
is set in a frame assembly including the frame
112
and the magnetic circuit
107
.
Referring to
FIG. 12A
, the coil gauge
114
is formed by bonding a cylindrical coil holding portion
114
b
, made of a resin film or the like and having a predetermined thickness, to a cylindrical surface of a main unit
114
a
, made of metal or the like.
The outer diameter D
1
of the cylindrical surface of the main unit
114
a
(or inner diameter of the coil holding portion
114
b
) is substantially equal to the diameter of the center pole located at the center of the pole yoke
106
. Accordingly, the coil gauge
114
is designed such that the coil holding portion
114
b
is removably fitted to the center pole of the pole yoke
106
, as shown in FIG.
12
C.
The outer diameter D
2
of the coil holding portion
114
b
is substantially equal to the inner diameter D
3
of the voice coil bobbin
103
, as shown in FIG.
12
B. Accordingly, the coil holding portion
114
b
is designed to hold the voice coil bobbin
103
in such a manner that the voice coil bobbin
103
can be removably fitted to the coil holding portion
114
b.
As shown in
FIG. 12B
, the voice coil bobbin
103
, having the voice coil
102
wound thereon, is fitted to the coil gauge
114
. As shown in
FIG. 12C
, this coil gauge
114
is fitted to the center pole of the magnetic circuit
107
. This completes the preparatory process.
As a result of the preparatory process above, voice coil bobbin
103
and voice coil
102
are held in the magnetic gap of the magnetic circuit
107
without contacting the center pole of the pole yoke
106
or the plate
105
. Also, the positions of the voice coil bobbin
103
and the voice coil
102
relative to the pole yoke
106
and plate
105
are determined.
The next stage of the manufacturing process will be explained with reference to
FIG. 13A
to FIG.
13
D. First, as shown in
FIG. 13A
, the damper
109
is placed at a predetermined position in the frame assembly. Then, the coil gauge
114
, on which the voice coil bobbin
103
and voice coil
102
have been mounted in the preparatory process explained above is inserted into the center hole of the damper
109
and fitted to the center pole of the pole yoke
106
.
Next, the inner circumference and the outer circumference of the damper
109
are fixed to the voice coil bobbin
103
and the frame assembly, respectively, with an adhesive agent. Here, the leads of the voice coil
102
are extracted to the upper side of the damper
109
.
As shown in
FIG. 13B
, the diaphragm
101
having the edge
108
attached thereto is placed on the frame assembly, and the position of the diaphragm
101
, relative to the voice coil
102
, is fixed. Then, the outer circumference of the edge
108
is fixed to the frame assembly and the inner circumference of the diaphragm
101
is fixed to the voice coil bobbin
103
with an adhesive agent or the like. Because the motion of the voice coil bobbin
103
is restricted by the coil gauge
114
, the relative positional relationship between the voice coil
102
and diaphragm
101
remains fixed during the attachment of the diaphragm
101
.
As shown in
FIG. 13C
, each lead of the voice coil
102
is soldered to an eyelet on the diaphragm
101
. The coil gauge
114
is then removed from the voice coil bobbin
103
.
Next, the center cap
113
is fixed at the center of the diaphragm
101
with an adhesive agent, as shown in FIG.
13
D. On the back side of the diaphragm
101
, the ends of the voice coil
102
are connected to a pair of terminals
110
through the paired lead wires
111
. The cone type speaker unit is thus completed.
As described above, during the manufacture of the cone type speaker unit, the relative positions of the diaphragm
101
, damper
109
, and voice coil bobbin
103
need to be fixed with high precision. Therefore, until the diaphragm
101
and damper
109
are fixed to the voice coil bobbin
103
with an adhesive agent, the coil gauge
114
is necessary. For this reason, a center hole slightly larger than the maximum diameter of the coil gauge
114
at the center of the diaphragm
101
must be created.
Because the structural strength of the diaphragm
101
is reduced by this center hole, the center cap
113
normally is used to reinforce the structure. However, to form the diaphragm
101
having high stiffness with a predetermined thickness, it is preferable to form the diaphragm
101
and the center cap
113
as one piece.
The diaphragm
101
needs to have a high stiffness and to radiate acoustic waves with the same or equivalent phases throughout its entire
Abe Yasuhisa
Murayama Fumio
Tokusho Takeshi
Kim Paul D
Pioneer Electronic Corporation
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