Method of producing stator of variable capacitor

Details Method of producing stator of variable capacitor Method of producing stator of variable capacitor

2001-02-07

2003-09-30

Vo, Peter (Department: 3729)

Metal working

Electric condenser making

Solid dielectric type

C029S831000, C029S832000, C029S846000, C029S847000, C451S041000

Reexamination Certificate

active

06625858

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing a stator for a variable capacitor, and more particularly, to a method of producing the stator including a polishing step. Further, the present invention relates to a variable capacitor including the stator produced by the above-described production method.
2. Description of the Related Art
A conventional variable capacitor is described in Japanese Unexamined Patent Publication Application No. 11-87173.
FIGS. 4
to
6
show the variable capacitor described in this Unexamined Patent Publication Application No. 11-87173.
FIG. 4
is a perspective view of a variable capacitor
1
.
FIG. 5
is a perspective view of the variable capacitor
1
of
FIG. 4
, taken from below the variable capacitor
1
.
FIG. 6
is a cross-sectional view of the variable capacitor
1
shown in FIG.
4
.
The variable capacitor
1
includes a stator
2
, a rotor
3
, and a cover
4
which define the capacitor
1
.
In particular, the stator
2
is made of a ceramic dielectric, and has first and second main surfaces
21
and
22
which are parallel to each other, and a side surface
23
connecting the first and second main surfaces
21
and
22
. Moreover, stator electrodes
5
and
6
are arranged inside of the stator
2
to extend parallel to the first and second main surfaces
21
and
22
, respectively. Stator terminals
7
and
8
are made of conductive films and extend on a portion of the side surface
23
, and more particularly, on the outer end-surfaces of the stator.
The two stator electrodes
5
and
6
and the two stator terminals
7
and
8
are provided as described above, such that the structure of the stator
2
is symmetrical, and accordingly, it is unnecessary to consider the direction of the stator
2
when the variable capacitor
1
is produced. In the capacitor
1
illustrated in
FIGS. 4 and 6
, the stator electrode
5
and the stator terminal
7
operate, while the stator electrode
6
and the stator terminal
8
do not operate.
On the main surface
22
of the stator
2
, a rib
9
is arranged to extend longitudinally through the approximate center portion of the main surface
22
.
The rotor
3
is made of conductive metal, and is provided on the first main surface
21
of the above-described stator
2
. On the underside of the rotor
3
, a substantially half-circular rotor electrode
11
with a protuberant step-portion is provided. Moreover, on the underside of the rotor
3
, a protuberance
12
having the same height as the rotor electrode
11
is provided, and inclination of the rotor
2
is prevented due to the present of the rotor electrode
11
. The rotor
3
is provided with a driver recess
13
to receive a tool, such as a driver or other suitable tool with which the rotor
3
is rotation-operated.
The cover
4
is made of conductive metal, receives the rotor
3
, and is fixed to the stator
2
. The rotor
3
is held by the cover
4
and is rotatable with respect to the stator
2
.
In the cover
4
, an adjustment hole
14
is provided to expose the driver recess
13
of the rotor
3
. In the periphery of the adjustment hole
14
, a spring action portion
15
is provided which is in contact with the rotor
3
and presses the rotor
3
against the stator
2
. The spring action portion
15
is inclined downwardly at the periphery of the adjustment hole
14
, toward the center of the adjustment hole
14
, and moreover, is provided with a plurality of protuberances
16
.
Moreover, the cover
4
is provided with engagement pieces
17
and
18
extending downward in opposition to each other. The engagement pieces
17
and
18
are bent to engage with the main surface
22
of the stator
2
, and thereby, the cover
4
is fixed to the stator
2
. The above-described rib
9
provided for the stator
2
protrudes the same amount as the engagement pieces
17
and
18
bent onto and along the second main surface
22
of the stator
2
, such that the variable capacitor
1
is stably and securely mounted on an appropriate wiring substrate (not shown).
Furthermore, on the cover
4
, a rotor terminal
19
is provided and extends downward.
In the variable capacitor
1
having the above-described structure, the rotor electrode
11
, which is in contact with the first main surface
21
of the stator
2
, is opposed to the stator electrode
5
via a portion of the ceramic dielectric defining the stator
2
, and thereby, a static capacity is produced. The rotor
3
is rotationally operated to vary the effective opposition area of the rotor electrode
11
opposed to the stator electrode
5
to change the static capacity. The adjusted static capacity is drawn between the stator terminal
7
electrically connected to the stator electrode
5
and the rotor terminal
19
provided on the cover
4
in contact with the rotor
3
having the rotor electrode
11
provided thereon.
In the above variable capacitor
1
, to increase the maximum static capacity and obtain a stable static capacity, the first main surface
21
of the stator
2
is polished such that the thickness of the dielectric between the main surface
21
and the stator electrodes
5
and
6
is reduced, and the main surface
21
in contact with the rotor electrode
11
is smoother.
Moreover, the first main surface
21
of the stator
2
is polished for the following additional purpose.
The conductive films defining the above-described stator terminals
7
and
8
are formed, e.g. by dipping the respective end portions of the stator
2
into a bath including a conductive paste having a desired thickness to apply the conductive paste to the respective end portions of the stator
2
, and then, baking the paste. Thus, the conductive films are provided not only on the side surface
23
of the stator
2
, but also extend from the side surfaces
23
onto a portion of the first and second main surfaces
21
and
22
.
However, in the variable capacitor
1
, as shown in
FIGS. 4 and 6
, the stator terminals
7
and
8
do not extend on the first main surface
21
of the stator
2
. Thus, to obtain this configuration of the stator terminals
7
and
8
, after the conductive films are formed as described above, the first main surface
21
of the stator
2
is polished such that the conductive films on the first main surface
21
are removed.
The upper ends of the stator terminals
7
and
8
can be positioned at a relatively large distance from the edge of the cover
4
or the peripheral surface of the rotor
3
by preventing the formation of the stator terminals
7
and
8
on the first main surface
21
of the stator
2
as described above.
Accordingly, if an error in positioning of the rotor
3
and the cover
4
with respect to the stator
2
occurs when the variable capacitor
1
is produced, or a deviation in position of the cover
4
and the rotor
3
is generated when the rotor
3
is rotated, short-circuiting and deficient withstand voltage will not occur between the edge of the cover
4
and the upper end portions of the respective stator terminals
7
and
8
, or between the peripheral surface of the rotor
3
and the upper end portions of the respective stator terminals
7
and
8
.
When the first main surface
21
of the above-described stator
21
is polished, conventionally, the plurality of stators
2
are simultaneously processed to improve the efficiency of the polishing process.
FIGS. 7A
to
7
D illustrate a conventional polishing method used to achieve the above-described polishing. It should be noted that
FIGS. 7A
to
7
D are also used for illustration of the problems to be solved by the present invention, as described later.
FIGS. 7A
to
7
D schematically show the stators
2
shown in
FIGS. 4
to
6
, and the elements in
FIG. 7
corresponding to those in
FIGS. 4
to
6
are designated by the same reference numerals. Moreover, stator components defining the stators
2
are designated by reference numeral
2
a
in FIG.
7
.
The plurality of stator components
2
a
are prepared as shown in FIG.
7
A. In each of the stator c

Affiliated with

Also associated with

Rating

Method of producing stator of variable capacitor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of producing stator of variable capacitor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing stator of variable capacitor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3089239