JP2003249816A - Antenna coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make small the size of a small transmitting/receiving antenna part for a keyless system of vehicle key or for house key and increase its performance. <P>SOLUTION: A magnetic core member 1 as a flat plate is formed with winding recesses 11 and 12, cut toward its centers from its four sides and with winding grooves 13 and 14 made in the outer peripheral surfaces of the recesses other than recess formation parts, X- and Y-axis windings 2 and 3 of a cruciform are wound around the cut recesses, and Z-axis windings are wound around the outer peripheral grooves, thus forming a triaxial antenna. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small antenna coil used as a transmitting / receiving antenna for a keyless system for a vehicle key and a house key.

[0002]

DISCLOSURE OF THE INVENTION Instead of directly using the key, whether the key is opened or closed is determined by a radio signal, and
In a key system for opening and closing a key, an antenna coil is adopted as an antenna for transmitting and receiving radio signals. Since this antenna coil has a small output, a multi-axis antenna coil is adopted to ensure multi-direction.

In the conventional multi-axis coil, a core body is wound in a cross shape to form a biaxial antenna coil, and one axis is formed by winding another core body. For this reason, the whole becomes bulky and cannot be made smaller.

Therefore, a single three-axis antenna coil can be obtained by winding a single core body in three axial directions. However, a single three-axis antenna coil is directly attached to a rectangular or cubic core body (usually ferrite). When the axial winding is applied, a step is formed between the outer peripheral side winding at the winding crossing portion and the non-crossing portion, the winding is apt to be disturbed, and its manufacturing becomes complicated.

Further, if the core body itself is made small in order to cope with the miniaturization of the antenna parts, in order to ensure the desired performance, the number of windings is increased, resulting in a so-called winding thick structure, and conversely winding. If the core body is enlarged in order to reduce the number of wires, there arises a problem that the miniaturization as an antenna component cannot be achieved.

Of course, in order to stabilize the winding, it is considered to use a winding bobbin for three axes which serves as each guide of the three-axis winding. However, even if the bobbin is used, there is a problem with the size of the core body and the antenna capability. Not resolved.

Therefore, the present invention proposes a three-axis type antenna coil which has a novel core shape to solve the problems of miniaturization of antenna parts and improvement of antenna performance.

[0008]

An antenna coil according to the present invention is a flat plate-like body, and is provided with winding recesses cut in the four sides from the sides, and the outer peripheral surface of the side where the recess is not formed. A core body having a groove for winding is formed on the core body, and the core body is provided with a cross-shaped winding that winds a facing recess and a winding that winds a peripheral groove to form a triaxial antenna. It is characterized by becoming.

The cross-shaped windings (X-axis coil and Y-axis coil) are fitted in the cut groove recesses, and the peripheral winding (Z-axis coil) is fitted in the outer peripheral groove, so that each winding is firmly attached to the core body. And maintained. In addition, in particular, the present invention, in the above antenna coil, forming a cross-shaped shallow groove corresponding to the recess on the front and back of the plate-shaped body, making one of the shallow grooves deeper than the other, and further forming the depth of the outer peripheral groove, It is characterized in that it is formed to be shallower than the cut recess.

Since the X-axis coil winds the notch recess and the deep grooves on the front and back surfaces, and the Y-axis coil winds the notch recess and the shallow groove at the cross position, the step problem at the intersection of the XY-axis coil occurs. Will be resolved. Further, since the depth of the outer peripheral groove is shallower than that of the cut recess, the XY range is set within the range of the depth difference.
Since the axial coil is wound, the step problem in the overlapping portion of the Z-axis coil and the XY-axis coil can be solved.

Further, according to the present invention, since the core body having the above-mentioned structure is made of a magnetic material, as compared with an antenna component in which a winding is wound around a rectangular parallelepiped magnetic material core to have the same size, The antenna performance is remarkably improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described. The antenna coil shown in the embodiment is obtained by winding the XYZ axis coils 2, 3 and 4 around the core body 1 shown in FIG.

The core body 1 is made of ferrite in the following predetermined shape, and has a flat plate shape (outer shape 11.9) as a whole.
It is a rectangular parallelepiped of × 11.9 × 3.0 mm, in which a square portion is obliquely removed), and a rectangular cut concave portion (width 4.0 mm, depth 1.7) is provided on one of the opposite sides of the opposite side.
mm) 11a and 11b are provided, and the cutout recess (width 3.3 mm, depth 1.7 mm) 12 is also formed on the other side.
a and 12b are provided.

Further, on the front and back surfaces of the core body, deep grooves (width 3.6 mm, depth 0.
9 mm) 13 and a shallow groove (width 4.0 mm, depth 0.45 mm) 14 is formed between the cut recesses 12a and 12b.

Further, the cut recesses 11a, 11b, 1
Peripheral grooves (groove width 1.5
mm, groove depth 0.8 mm) 15.

To form an antenna component, a winding is applied to the core body 1, and the X-axis coil 2 is a winding having an appropriate thickness (3 type UEW wire 0.040 mm: the same applies to other axis windings hereinafter). )
To the notches 11a and 11b and the deep grooves 13 on the front and back sides as appropriate (about 400 to 450 times: the same applies to other shaft windings).
It will be wound.

The Y-axis coil 3 is wound around the cut recesses 12a, 12b and the shallow grooves 14 on the front and back sides after the X-axis coil 2 is wound, and the X-axis coil 2 is accommodated in the deep groove 13. The winding step does not occur at the coil crossing part.

Further, the Z-axis coil 4 is an XY-axis coil 2, 3
After being wound around the outer peripheral groove 15 of the core body 1,
The XY-axis coils 2 and 3 at the intersecting portions are provided with the respective cut recesses 1.
It is within 1 and 12, and there is no step due to the overlapping of the coil intersecting portions.

In order to confirm the performance of the antenna parts, prototypes B and C were prototyped and comparative tests were conducted. Prototypes b and c are triaxial windings x1 and y on the rectangular parallelepiped cores a1 and a2 made of ferrite, which is the same material as the flat plate shaped product a.
1, z1, x2, y2, z2 are applied, and the windings 2, 3 and 4 of the product a of the present invention and the windings x of prototype B and C
1, 1, y1, z1, x2, y2, z2 are the same wire rod (3 types UEW wire 0.040 mm) and the same number of turns (4
(00 times). The prototypes B and C use plastic bobbins b1 and b2 that serve as winding guides so that the winding can be wound stably.

In particular, in the prototype B, the core body a1 has a size of "10 × 1" so that the external size of the component is similar to that of the product B.
0 × 1 mm ”, and the prototype C has a dimension of“ 12 ×
12 × 3 mm ”.

In the test, as illustrated in FIG. 4, an electric field is formed with a predetermined output, and a test product (implemented product a, prototype b, c)
It is a measurement of the peak value of the voltage induced in the coil. In particular, since the capacitance component of the probe influences the measurement, the resonance capacitor capacitance obtained from the Ls value was adjusted with a trimmer capacitor to obtain resonance, and the effective value was measured.

The measurement results are shown in the table of FIG. Therefore, when compared with the prototype B, which has a similar external shape of parts,
It was confirmed that there was a marked difference in performance, and that the performance was excellent even when compared with the prototype C, which had a size similar to the core body.

The shape of the core body of the present invention is not limited to the above-mentioned embodiment, and the coil (XY) crossing in a cross shape can be used.
It has four sides that can be wound with an axial coil), and XY
A disk body or a polygonal flat body other than the above-described embodiment may be used as long as the coil (Z-axis coil) can be wound orthogonally to the axial coil, and a cube or a rectangular parallelepiped having an appropriate thickness, and further It may be a spherical body or the like. Of course, the size and winding conditions can be arbitrarily determined.

[0024]

As described above, the present invention is a flat plate-shaped body,
A core body is formed on each of which four sides are provided with a winding recess cut in the center from the side, and a winding groove is provided on the outer peripheral surface of the side where the recess is not formed. A small antenna can be easily formed with a cross-shaped winding around the notched concave portion and an antenna coil that forms a three-axis antenna by winding around the outer circumferential groove. By adopting this, a compact and high-performance antenna coil could be obtained.

[Brief description of drawings]

FIG. 1 is a front view of a core body according to an embodiment of the present invention.

FIG. 2 is a side view in which the same portion is cut, (a) shows a core body, and (b) shows a state after coil winding.

FIG. 3 is a front view of the state after the coil is wound.

FIG. 4 is an explanatory diagram of the test.

FIG. 5 is an explanatory diagram of the test product.

FIG. 6 is a table showing the test results.

[Explanation of symbols]

1 core body 11a, 11b, 12a, 12b Notch recess 13 deep groove 14 shallow groove 15 peripheral groove 2 X-axis coil 3 Y-axis coil 4 Z-axis coil

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshihiro Katahara             7-55 Tsushimaya, Niigata City New Denshi Stock             In the company (72) Inventor Go Hamaya             7-55 Tsushimaya, Niigata City New Denshi Stock             In the company F term (reference) 2E250 AA21 BB08 BB22 CC20 FF22                       FF36 HH01 JJ03 KK03 LL01

Claims (3)

[Claims] 1. A core which is a flat plate-like body and is provided with winding recesses cut in the four sides from the sides, and winding grooves are provided on the outer peripheral surface of the side where the recess is not formed. An antenna coil, which is formed as a three-axis antenna by forming a body, and providing the core body with a cross-shaped winding wound around a facing recess and a winding wound around an outer peripheral groove. 2. A cross-shaped shallow groove corresponding to the recess is formed on the front and back of the plate-like body, one of the shallow grooves is made deeper than the other, and the depth of the outer peripheral groove is made shallower than the notched recess. The antenna coil according to claim 1, wherein 3. The antenna coil according to claim 1, wherein the core body is a magnetic body.