U.S. patent number 3,783,417 [Application Number 05/279,072] was granted by the patent office on 1974-01-01 for inductance coil.
This patent grant is currently assigned to TDK Electronic Company. Invention is credited to Tadaharu Akino, Hisasi Osada.
United States Patent |
3,783,417 |
Osada , et al. |
January 1, 1974 |
INDUCTANCE COIL
Abstract
An inductance coil is disclosed having a core with flanges at
both ends thereof. A partition wall is provided at an intermediate
part of the core so as to form at least two separate coil winding
spaces on the core between the two end flanges and the partition
wall. The coil winding spaces are exactly the same width and
windings are provided in the winding spaces with exactly the same
number of turns.
Inventors: |
Osada; Hisasi (Tokyo,
JA), Akino; Tadaharu (Tokyo, JA) |
Assignee: |
TDK Electronic Company (Tokyo,
JA)
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Family
ID: |
11581029 |
Appl.
No.: |
05/279,072 |
Filed: |
August 9, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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102596 |
Dec 30, 1970 |
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Foreign Application Priority Data
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Jan 14, 1970 [JA] |
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45/4315 |
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Current U.S.
Class: |
333/185 |
Current CPC
Class: |
H03H
7/32 (20130101) |
Current International
Class: |
H03H
7/30 (20060101); H03H 7/32 (20060101); H03h
007/32 () |
Field of
Search: |
;333/705,29 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Golay, M. J. E., "The Ideal Low-Pass Filter in the Form of a
Dispersionless Lag Line," Pro. Ire, Vol. 34, 1946, pp.
138-144..
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Primary Examiner: Rolinec; Rudolph V.
Assistant Examiner: Punter; Wm. H.
Attorney, Agent or Firm: Oblon, Fisher & Spivak
Parent Case Text
This is a division, of application Ser. No. 102,596, filed Dec. 30,
1970, now abandoned.
Claims
We claim:
1. A derived m-type filter comprising:
a cylindrical core having flange means at both ends thereof, both
of said end flange means having equal heights and widths and
comprised of essentially homogeneous masses;
intermediate flange means positioned on said core between said end
flange means;
coil winding regions defined by the spaces between said
intermediate flange means and said end flange means, each of said
coil winding regions having identical widths and heights;
coils wound around said core, one coil in each of said coil winding
regions, each of said coils having the same number of turns, and
each of said coils wound about said core in the same direction and
connected to one another in series at each of said intermediate
flange means; and
externally provided capacitor means coupled to said coils at each
of said connection points therebetween.
2. A derived m-type filter as set forth in claim 1, wherein: said
core and all said flange means are formed of ferrite.
3. A derived m-type filter as set forth in claim 1, wherein:
said intermediate flange means comprises a plurality of flange
members each comprised of an essentially homogeneous mass arranged
along said core at regular intervals.
4. A derived m-type filter as set forth in claim 1, wherein: all
said flange means are moulded integral with said core.
5. A derived m-type filter as set forth in claim 1, wherein: all
said flange means are disk shaped, having apertures in the centers
thereof whereby said flange means are mounted on said core.
6. A derived m-type filter as set forth in claim 5 wherein the
ratio of the diameter of said end flanges to the diameter of said
core is approximately 3:1.
Description
BACKGROUND OF THE INVENTION
1. Field Of The Invention:
This invention relates to an inductance coil, and more particularly
to an inductance coil for a derived m-type filter.
2. Description Of The Prior Art:
When a delay circuit is constructed by using a derived m-type
filter, it has been customary to use an inductance coil with a
winding arranged on a cylindrical core, and having a tap taken from
the middle portion of the winding. In this type of inductance coil,
when used for a derived m-type filter, it is absolutely necessary
that the self-inductance between one end of the winding and the
tap, and the self-inductance between the other end of the winding
and the tap should be equal, and that the mutual-inductance of both
parts of the coil should be a constant value. In addition, it is
most desirable that identical coils can be fabricated using mass
production techniques.
However, when inductance coils of the type described above are
produced in large quantities, it is very difficult to produce coils
having identical characteristics, and consequently self-inductance
and mutual-inductance become irregular.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a
novel and improved inductance coil for a derived m-type filter.
Another object of the present invention is to provide an inductance
coil for a derived m-type filter which can be manufactured in large
quantities with identical characteristics.
Still another object of the present invention is to provide an
inductance coil for a derived m-type filter which is suitable for
use in electronic computers, radars, and other devices which
require a large number of delay elements with equal delay time.
Yet another object of the invention is to provide an inductance
coil for a derived m-type filter wherein flanges provided on a
central core produce a special magnetic field.
Briefly, these and other objects are attained by producing an
inductance coil composed of a cylindrical core with a plurality of
flanges mounted on it.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and many of the attendant advantages of
this invention will be appreciated more readily as the same becomes
better understood by reference to the following detailed
description, when considered in connection with the accompanying
Drawings, wherein:
FIG. 1 is a schematic diagram of a conventional electrical circuit
illustrating an m-type filter;
FIG. 2 is a schematic diagram of a delay circuit using m-type
filters;
FIG. 3 is a perspective view of a conventional inductance coil of
the type which have been used in constructing m-type filters;
FIG. 4 is a perspective view of an inductance coil for m-type
filters in accordance with the present invention; and,
FIG. 5 is a cross-sectional view of the inductance coil shown in
FIG. 4, illustrating the dimensions and arrangement of the end
flanges, intermediate flange, and core of the present
invention.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Referring now to the Drawings, wherein like reference numerals
designate identical or corresponding parts throughout the several
views, and more particularly to FIG. 3 thereof, a conventional
inductance coil is shown as formed of a cylindrical core 1 made of
a conventional core material, around which a winding 2 is provided
having a tap 3 at the middle thereof. A pair of leads 4 and 5 are
provided at either end of coil 2. This inductance element is
usually employed in a derived m-type filter as shown in FIG. 1,
which may be used to construct a delay circuit by connecting a
plurality of filter elements in series as shown in FIG. 2.
In the inductance coil of FIG. 3, the self-inductance between tap 3
and either end of coil 2 should be equal, and the mutual-inductance
of the entire coil should be the same for all coils manufactured.
However, it is very difficult to fulfill the above requirements if
a conventional cylindrical core is employed. In addition, special
attention must be paid as to the number of turns wound on the core,
as well as to the position at which the tap is taken.
Reference is now made to FIGS. 4 and 5 of the Drawings in which the
inductance coil of the present invention is illustrated. The
inductance coil of the present invention comprises a drum core 6
having flanges 7 and 8 at both sides of the core, and an
intermediate flange or wall 9 at the center of the core. These
flanges and the wall are fabricated on the core by casting or by
grinding a round bar. The flanges and the wall may be made integral
with drum core 6, or may be made separate from core 6. In the
latter case, the flange is designed to be of disk-like shape, and
an aperture is provided at the center of the disk. This type of
flange is mounted on the core by inserting the core into the center
aperture of the flange, and the mounted flanges are then secured on
the core by welding or by other conventional means.
The drum core 6 is preferably of cylindrical shape, and has the
same circumference along its entire length.
In the preferred embodiment of the present invention, as shown in
FIGS. 4 and 5, flanges 7 and 8 are provided at the both ends of the
cylindrical drum core 6, and the intermediate part of the core 6
between the end flanges 7 and 8 has an intermediate flange 9 which
is substantially the same shape as the end flanges 7 and 8 in order
to divide the core 6 into at least two coil winding regions.
However, it should be understood that the number of intermediate
flanges placed between the end flanges is not limited, and a
plurality of intermediate flanges may be arranged along the core so
as to form a number of coil winding regions.
In the present invention, it should be noted that the intermediate
flange 9 is placed exactly in the middle of the core defined by end
flanges 7 and 8 in order to form coil winding regions having
exactly the same width at both sides of the intermediate flange
9.
As shown in FIG. 4, a pair of windings 10 and 11 are respectively
positioned in the coil winding regions defined by flanges 7, 9 and
8, 9. These windings are connected in series at the intermediate
flange 9 of the inductance elment. In practice, the winding coils
may consist of wires having diameters of from 0.2 to 0.3 mm. and
the windings may include from 20 to 30 turns each, with both coils
wound in the same direction.
The drum core 6 and flanges 7 and 8 of the present invention may be
composed of a core material such as iron, silicon, steel,
permalloy, or permendure. It is preferable to use a dust core, such
as pure iron dust core, permalloy dust core, sendust core or
ferrite. In the preferred embodiment, the diameter of the end
flanges may be on the order of 3 cm., and that of the core may be
on the order of 1 cm.
Although inductance coils having circular flanges have been
illustrated, it is contemplated that the flanges may be of many
other shapes, such as square, triangular and the like.
Referring now to FIG. 5, the following dimensions are
illustrated:
a.sub.1 : thickness of end flange 8
a.sub.2 :thickness of end flange 7
b.sub.1 :distance between end flange 8 and intermediate flange
9
b.sub.2 :distance between end flange 7 and intermediate flange
9
c.sub.1 :diameter of end flange 8
c.sub.2 : diameter of end flange 7
d : diameter of intermediate flange 9
e : thickness of intermediate flange 9
f.sub.1 : diameter of the central core at the position of coil
11
f.sub.2 : diameter of the central core at the position of coil
10
Observing these dimensions, the self-inductance of coils 10 and 11
can easily be made equal if core 6 is made such that:
a.sub.1 = a.sub.2
b.sub.1 = b.sub.2
c.sub.1 = c.sub.2, and
f.sub.1 = f.sub.2
In addition, the mutual inductance of the coil can be set to a
particular value by properly selecting the dimensions d and e.
Obviously, many modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described.
* * * * *