Loudspeaker

Details Loudspeaker Loudspeaker

1998-12-01

2003-07-22

Barnie, Rexford (Department: 2643)

Electrical audio signal processing systems and devices

Electro-acoustic audio transducer

Electromagnetic

C381S403000, C381S404000, C381S398000, C381S396000, C381S412000

Reexamination Certificate

active

06597798

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a loudspeaker, and more particularly to a damper provided in the loudspeaker.
A loudspeaker provided in an audio system is an electroacoustic device that converts an electric signal (electrical energy) into an acoustic signal (sound energy). ELectrodynamic loudspeakers, which are superior in quality of the reproduced sound and other properties are widely used today.
The loudspeakers are mounted in audio systems of various shapes, so that it is preferable to reduce the thickness of the speaker as much as possible.
FIGS. 4
a
and
4
b
are a plan view and a sectional view showing a main part of a conventional electrodynamic loudspeaker, respectively. Referring to the figures, the conventional electrodynamic loudspeaker has a yoke
103
, magnet
102
mounted on the yoke
103
, and a pole piece
101
mounted on the magnet, thereby forming a magnetic circuit including an annular magnetic gap.
The magnetic gap is formed between the pole piece
101
and the yoke
103
, the distance there-between being maintained substantially constant along the entire length. A frame
104
made of such a material as a resin is attached to the yoke
103
along the outer periphery thereof, thereby forming a frame assembly as well as the magnetic circuit.
A conical diaphragm
105
having a center hole is mounted above the pole piece
101
. The outer periphery of the diaphragm
105
is secured to the frame
104
through an edge
106
attached to the frame.
A cylindrical voice coil bobbin
108
a
is provided in the hole of the diaphragm
105
, the upper periphery attached thereto. A voice coil
108
is mounted in a space between the yoke
103
and the pole piece
101
, surrounding the bobbin
108
a.
The voice coil bobbin
108
a
is supported by the frame
104
through a damper
107
. The damper
107
resiliently supports the diaphragm
105
held by the edge
106
, voice coil
108
and the voice coil bobbin
108
a
at the respective predetermined positions, and further suspensively supports the voice coil
108
within the magnetic gap.
In order to reinforce the diaphragm
105
, a cap
110
is mounted on the center portion of the diaphragm
105
, so as to cover the center hole thereof.
The ends of the voice coil
108
are directed out of the coil bobbin
108
a
so as to be connected to leads
108
b
. Each lead
108
b
is securely mounted on the outer wall of the voice coil bobbin
108
a
and on the upper surface of the diaphragm
105
by an adhesive A. Each lead
108
b
further passes through the diaphragm
105
to the underside thereof, and is electrically connected to a terminal
109
provided on the frame
104
.
In the thus constructed loudspeaker, when applied with driving current through the terminals
109
, the suspended voice coil
108
generates a driving force. The driving force renders the voice coil bobbin
108
a
to vibrate the diaphragm
105
, thereby generating sounds.
Since the diaphragm
105
is deflected in the driving direction in operation, in order to prevent the diaphragm
105
from tensing and being exerted with a load, it necessary for each of the leads
108
to have a sufficient length between the diaphragm and the terminal
109
to keep the lead lax.
However, when the length of the lead
108
b
is long, due to the natural frequency thereof, the lead
108
b
may be deflected in a direction opposite from the moving direction of the diaphragm
105
and the damper
107
during the operation. As a result, the leads
108
b
collide against the diaphragm and the damper, thereby giving a shock. Consequently, a noise may be generated in the reproduced sound, and the lead
108
may be cut off.
In order to prevent such an accident, a sufficient space is needed between the diaphragm
105
and the damper
107
so that the leads
108
b
do not contact either of them. As a result, the thickness of the loudspeaker in the driving direction of the diaphragm is increased so that there is a limit in rendering the loudspeaker thin.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a loudspeaker having a reduced thickness wherein the lead is prevented from colliding against the diaphragm and the damper.
According to the present invention, there is provided a loudspeaker having a cylindrical frame, a magnetic circuit formed on the frame, a voice coil disposed in a magnetic gap of the magnetic circuit, a diaphragm, comprising, a damper attached to the frame and supporting the voice coil, and leads connected to both ends of the voice coil, the leads being attached to the damper from an inner portion to an outer portion by stitching.
The present invention further provides a loudspeaker having a cylindrical frame, a magnetic circuit formed on the frame, a voice coil disposed in a magnetic gap of the magnetic circuit, a diaphragm, comprising, an annular damper attached to the frame at an outer periphery and connected to the voice coil at an inner periphery so as to support the voice coil in a floating state, leads connected to both ends of the voice coil, the leads being attached to the damper from an inner portion to an outer portion by stitching.
The damper has a corrugated sectional shape, and each of the leads is spirally disposed on the damper.


REFERENCES:
patent: 3014996 (1961-12-01), Swanson
patent: 5091958 (1992-02-01), Sakamoto
patent: 5757945 (1998-05-01), Sakamoto
patent: 6269167 (2001-07-01), Mango

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