JPH09260161A - Inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a high inductance and a high impedance in a wide range of frequency. SOLUTION: A body part 3 of a core 2 has a small diameter part 3a and a large diameter part 3b. A piece of wire 8 starts being wound from the small diameter part 3a in alignment. When a first layer of winding is finished, a second layer is wound in overlaying the first layer. When the second layer is finished, a third layer is wound in overlaying the second layer. When the third layer is finished on the small diameter part 3a, a first layer of the large diameter is successively started. When the first layer of the large diameter 3b is finished, ends 8a and 8b of the piece of wire 8 are electrically connected to the outer electrodes 6 and 7 by soldering or welding.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an inductor, and more particularly to an inductor for a wide frequency band.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional winding type inductor 41 is composed of a winding core 42 and a wire 46. The winding core 42 includes a body portion 43 having a uniform diameter, and collar portions 44 and 45 provided at both ends of the body portion 43, respectively. The wire 46 is wound around the body 43.

[0003]

However, in the conventional inductor 41, if the inductance is made large and small, multiple winding of the wire is required. Therefore, the stray capacitance between the wound wire materials increases, and the impedance-frequency characteristic has a sharp peak portion as shown by the curve 47a shown in FIG. I couldn't keep up. Therefore, if a single layer winding with a small stray capacitance is adopted for the purpose of extending the self-resonant frequency to the high frequency range, the impedance in the low frequency range becomes small and the impedance in the wide frequency band decreases, as shown by the curve 47b in FIG. Couldn't get an inductor with.

Similarly, in the conventional choke coil, if the inductance is made large and small, multiple windings of the wire are required, and the inductance-frequency characteristics cannot maintain high inductance up to a high frequency range. If a single layer winding with a small stray capacitance is adopted for the purpose of extending the self-resonant frequency to a high frequency range, a large inductance cannot be obtained due to the limitation of the number of turns. As described above, it is difficult to design a choke coil having high inductance in a wide frequency band.

Therefore, an object of the present invention is to provide an inductor capable of ensuring high inductance and high impedance in a wide frequency range.

[0006]

In order to achieve the above object, an inductor according to the present invention has a core having at least two kinds of barrels having different diameters, and a wire rod wound around the barrel. And the number of lapped windings of the wire increases as the diameter of the body decreases. Here, the wire wound around the largest diameter portion of the body may be either single layer winding or multiple winding.

[0007]

With the above construction, since the winding core has at least two body portions having different diameters, a structure in which the number of overlapping windings is partially different can be obtained by simply winding the wire around the winding core. To be Then, the wire rod portion wound on the small diameter portion generates high inductance or high impedance in the low frequency region, and the wire rod portion wound on the large diameter portion generates wide band inductance or high impedance in the high frequency region. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an inductor according to the present invention will be described below with reference to the accompanying drawings. [First Embodiment, FIG. 1 and FIG. 2] As shown in FIG. 1, a chip coil 1 includes a body 3 and magnetic cores 2 including collars 4 and 5 provided at both ends of the body 3. And a wire rod 8 wound around the body portion 3 of the winding core 2. For example, ferrite or the like is used as the material of the winding core 2. As the wire rod 8, for example, a polyurethane-coated copper wire or the like is used.

The collar portions 4 and 5 are, for example, rectangular, and external electrodes 6 and 7 are provided on the outer peripheral surface and the side surface, respectively.
The body 3 has a circular cross section, and the left half of the body 3 is a small diameter portion 3a and the right half is a large diameter portion 3b. Small diameter part 3
The length and diameter of each of a and the large-diameter portion 3b are appropriately selected so that desired inductance-frequency characteristics can be obtained.

The wire rod 8 is aligned and started to be wound from the small-diameter portion 3a of the body portion 3, and when the first layer is finished to be wound, the second layer is wound over the first layer. After the second layer is wound, the third layer is then wound over the second layer. Then, when the third layer of the small diameter portion 3a is finished winding, the first layer of the large diameter portion 3b is subsequently started to be wound. When the first layer of the large-diameter portion 3b has been wound, the terminals 8a and 8b of the wire 8 are electrically connected to the external electrodes 6 and 7, respectively, by means such as soldering or welding. After this, the exterior material is molded or covered with a sleeve to obtain a product.

In the chip coil 1 thus obtained, the portion of the wire rod 8 wound around the small diameter portion 3a is a three-layer multiple winding, and the portion of the wire rod 8 wound around the large diameter portion 3b is formed. It is wound in a single layer. The three-layer multiple winding has large inductance and stray capacitance, and the single-layer winding has small inductance and stray capacitance. Therefore, the portion of the wire rod 8 wound around the small diameter portion 3a can generate high impedance in the low frequency region, and the portion of the wire rod 8 wound around the large diameter portion 3b can generate high impedance in the high frequency region. . FIG. 2 is a graph showing the impedance-frequency characteristics of the chip coil 1 (see the solid line 11). For comparison, FIG. 2 also shows the characteristics of a conventional chip coil in which a wire rod is multiple-wound around a winding core having a body of uniform diameter (dotted line 1).
2).

[Second Embodiment, FIGS. 3 and 4] As shown in FIG. 3, the chip common mode choke coil 21 includes:
The body portion 23 and the collar portions 24, 2 provided at both ends of the body portion 23.
The magnetic core 22 is composed of the magnetic core 5, and the pair of wires 31 and 32 are wound around the body portion 23 of the core 22. The flanges 24 and 25 have external electrodes 2 on the outer peripheral surface and the side surface, respectively.
6, 27, 28 and 29 are provided. The body 23 has a circular cross section, and the left half of the body 23 is the small diameter portion 23.
a, the right half is a large diameter portion 23b. Small diameter part 23
The length and diameter of each of the a and the large diameter portion 23b are appropriately selected so that desired impedance-frequency characteristics can be obtained.

The pair of wires 31, 32 are bifilarly wound and aligned and started to be wound from the small diameter portion 23a of the body portion 23, and when the first layer is finished, the second layer is placed on the first layer. It is wound repeatedly. When the second layer has finished winding, then the third layer
The second layer is overlaid on the second layer. Then, when the third layer of the small diameter portion 23a has finished winding, the large diameter portion 23b continues.
The first layer of is started to be wound. When the first layer of the large-diameter portion 23b has finished winding, the ends 31a, 31 of the wire rods 31, 32
b, 32a and 32b are external electrodes 26, 28 and 2 respectively.
It is electrically connected to 7, 29 by means such as soldering or welding. After this, the exterior material is molded or covered with a sleeve to obtain a product.

The choke coil 21 thus obtained is
The portions of the wire rods 31 and 32 wound around the small diameter portion 23a are three-layer multiple windings, and the portions of the wire rods 31 and 32 wound around the large diameter portion 23b are single layer windings. 3
The layer multiple winding increases impedance, and the single layer winding acts to suppress stray capacitance. Therefore, the small diameter portion 23a
The portions of the wire rods 31 and 32 wound around the high-frequency region can generate high impedance, and the portions of the wire rods 31 and 32 wound around the large-diameter portion 23b can generate high impedance in the high-frequency region. FIG. 4 is a graph showing the impedance-frequency characteristics of the chip common mode choke coil 21 (see the solid line 34). For comparison, FIG. 4 also shows the characteristics of a conventional choke coil in which a pair of wire rods are multi-wound by bifilar windings around a winding core having a uniform diameter (see dotted line 35). ).

[Other Embodiments] It should be noted that the inductor according to the present invention is not limited to the above-mentioned embodiment, and can be variously modified within the scope of the gist thereof. The cross-sectional shape of the winding core is not limited to a circular shape, but may be a rectangular shape or the like. Also, the core is made of ferrite magnetic material,
It may be made of a dielectric ceramic, an insulating resin, or the like, and is manufactured by molding, firing, or cutting these magnetic material, derivative, or insulating material. Further, the winding core may have two or more different diameters, and the number thereof does not matter. The procedure of winding the wire around the body of the winding core is not necessarily limited to the small diameter portion, and may be performed arbitrarily.

[0016]

As is apparent from the above description, according to the present invention, since the winding core has the body portions having at least two kinds of different diameters, the wire is simply wound around the winding core. Thus, it is easy to obtain an inductor in which the number of overlapping turns is partially different. Then, the wire rod portion wound around the small diameter portion generates high inductance or high impedance in the low frequency region, and the wire rod portion wound around the large diameter portion generates high inductance or high impedance in the high frequency region. be able to. As a result, an inductor that can secure high inductance and high impedance in a wide frequency range can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of an inductor according to the present invention.

FIG. 2 is a graph showing impedance-frequency characteristics of the inductor shown in FIG.

FIG. 3 is a sectional view showing a second embodiment of the inductor according to the present invention.

FIG. 4 is a graph showing impedance-frequency characteristics of the inductor shown in FIG.

FIG. 5 is a sectional view showing a conventional inductor.

6 is a graph showing impedance-frequency characteristics of the conventional inductor shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Chip coil 2 ... Winding core 3 ... Body part 3a ... Small diameter part 3b ... Large diameter part 8 ... Wire material 21 ... Chip common mode choke coil 22 ... Winding core 23 ... Body part 23a ... Small diameter part 23b ... Large diameter part 31, 32 ... Wire rod

Claims (1)

[Claims] 1. A core comprising at least two types of barrels having different diameters, and a wire wound around the barrel,
An inductor characterized in that the number of lapped windings of the wire increases as the diameter of the body decreases.