JPH07302712A - Multilayered inductor - Google Patents

Abstract

PURPOSE:To obtain a multilayered inductor which restrains temperature rise caused by self heat generation and can set a large rated current. CONSTITUTION:A multilayered body 1 is constituted by stacking insulator sheets wherein conductors for coil use are laid on the surfaces. I/O electrodes 16, 17 are formed on both end portions of the body 1. Radiation electrodes 18a, 18b are formed on the side surface central parts in this side and the depth side. The I/O electrodes 16, 17 are electrically connected with a coil constituted of conductor for coil use. The radiation electrodes 18a, 18b are not connected with conductor. As the material of the radiation electrodes 18a, 18b, material excellent in the thermal conductivity as compared with the material of the insulator sheet, e.g., Ag, Pd, etc., are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductor, and more particularly to a laminated inductor used as a choke coil or the like.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional laminated inductor 61 has input / output electrodes 63 and 64 at both ends of a laminated body 62 formed by stacking an insulator and a coil conductor.
Was provided. The input / output electrodes 63 and 64 are electrically connected to the coil formed of the coil conductor. In the laminated inductor 61 having such a structure, the DC resistance of the coil is larger than that of the wound inductor,
There is a problem that the temperature rise due to self-heating becomes large and the rated current cannot be increased.

For this reason, measures such as adopting a material having a high electrical conductivity as the material for the coil conductor and increasing the thickness of the coil conductor have been proposed, but during the manufacturing process (especially during firing). There are new problems such as cracks and high manufacturing costs. Therefore, an object of the present invention is to provide a laminated inductor capable of suppressing a temperature rise due to self-heating and setting a large rated current.

[0004]

In order to solve the above problems, a laminated inductor according to the present invention comprises: (a) a laminated body formed by stacking an insulator and a coil conductor.
(B) an input / output electrode that is provided on the surface of the laminate and that is electrically connected to the coil configured by the coil conductor; and (c) any conductor provided on the surface of the laminate. And a heat dissipation electrode which is not connected to. As the material of the heat dissipation electrode, a material having excellent thermal conductivity is used.

With the above structure, the heat generated in the coil due to the current flowing through the coil is conducted to the heat radiating electrode provided on the surface of the laminated body through the insulator, and further from the heat radiating electrode to the air or the laminated type. The heat is dissipated to a conductive path such as a printed wiring board on which the inductor is mounted. Therefore, it becomes difficult for the temperature of the multilayer inductor to rise. Further, the multilayer inductor according to the present invention includes (d) a laminated body formed by stacking an insulator, a coil conductor, and a heat absorbing electrode, and (e) a coil conductor provided on the surface of the laminated body. An input / output electrode electrically connected to the coil configured as
(F) A heat dissipation electrode provided on the surface of the laminate and connected to the heat absorption electrode. As the material of the heat absorbing electrode or the heat radiating electrode, a material having excellent thermal conductivity is used.

With the above structure, the heat generated in the coil is conducted to the heat absorbing electrode through the insulator and then to the heat radiating electrode efficiently. Then, the heat is dissipated from the heat dissipation electrode into the air or a conductive path such as a printed wiring board on which the laminated inductor is to be mounted. Therefore, it becomes more difficult for the temperature of the laminated inductor to rise.

[0007]

Embodiments of the laminated inductor according to the present invention will be described below with reference to the accompanying drawings. [First Embodiment, FIGS. 1 to 5] As shown in FIG. 1, the laminated body 1 includes an insulator sheet 2 and coil conductors 3, 4, 5, 6, and 7.
It is composed of. As a material of the insulator sheet 2,
For example, ferrite or the like is used. Coil conductors 3-7
May be formed by applying a paste of Ag, Pd, Cu or the like on the surface of the insulator sheet 2 by means of screen printing and drying, or by means of sputtering, vapor deposition or the like.

One end 3a of the coil conductor 3 is exposed on the left side of the insulator sheet 2. One end 7a of the coil conductor 7 is exposed on the right side of the insulator sheet 2. The insulating sheet 2 having the coil conductors 3 to 7 on the surface and the protective insulating sheet 2 having no surface on the surface are stacked, molded, and fired to form the laminated body 1.
In the stacked state, the coil conductors 3 to 7 are the via holes 10, 11, 1 provided in the insulator sheet 2, respectively.
The coils 8 are formed by being electrically connected in series via the electrodes 2 and 13.

As shown in FIG. 2, the molded laminate 1 is provided with input / output electrodes 16 and 17 at both ends, and heat radiation electrodes 18a and 18b are provided at the center of the front and rear side surfaces. The input / output electrode 16 is electrically connected to the end 3a of the coil conductor 3, and the input / output electrode 17 is electrically connected to the end 7a of the coil conductor 7. On the other hand, the heat dissipation electrode 18a,
18b is not connected to any conductor.

Input / output electrodes 16 and 17 and heat dissipation electrode 18
The a and 18b may be formed by applying a paste of Ag, Pd or the like to the laminated body 1 and baking it, or may be formed by a means such as sputtering or vapor deposition. In particular, the heat dissipation electrodes 18a and 18b may be made of a metal material or an insulating material other than Ag and Pd as long as they have a higher thermal conductivity than the material of the insulator sheet 2. Alternatively, a metal foil such as an aluminum foil or a copper foil may be attached to the surface of the laminate 1 to serve as a heat dissipation electrode. FIG. 3 is an electrical equivalent circuit diagram of the multilayer inductor thus obtained.

Next, the function and effect of mounting the laminated inductor on a printed wiring board will be described. As shown in FIG. 4, the input / output electrodes 16 and 17 of the laminated inductor are electrically connected to the conductor patterns 20 and 21 provided on the printed wiring board by solder 25, respectively, so that the laminated inductor serves as the printed wiring board. Fixed. In this state, when a current flows through the coil 8 built in the multilayer inductor, the heat generated in the coil 8 is transferred to the heat dissipation electrodes 18a and 18b via the insulator. The heat dissipation electrodes 18a and 18b dissipate the transferred heat to the air and suppress the temperature rise of the laminated inductor. As a result, it is possible to obtain a laminated inductor capable of setting a large rated current.

Further, as shown in FIG. 5, the input / output electrode 1
6, 17 and the heat dissipation electrodes 18a, 18b are soldered to the conductor patterns 22, 23, 24 provided on the printed wiring board, respectively.
The multilayer inductor may be fixed to the printed wiring board by electrically connecting at 5. In this case, when a current flows through the coil 8, the heat generated in the coil 8 is transferred to the heat dissipation electrodes 18a and 18b via the insulator. Heat dissipation electrode 18a,
The heat transmitted to 18b is also conducted to the conductor pattern 24 provided on the printed wiring board, and the heat is also radiated from the conductor pattern 24 to the air or the printed wiring board, further improving the heat dissipation effect. In the example of FIG. 5, the heat dissipation electrodes 18a and 18b are
Is not suitable when is an insulating material.

Further, when a current is passed through the coil, the temperature rise can be suppressed as compared with the conventional laminated inductor, so that the electrical and mechanical reliability of the laminated inductor is improved. [Second Embodiment, FIG. 6 and FIG. 7] The laminated inductor of the second embodiment is provided with a heat absorbing electrode inside. As shown in FIG. 6, the laminated body 31 includes an insulator sheet 32, coil conductors 33, 34, 35 and 36, and heat absorbing electrodes 40a and 40b.
It is composed of 41a, 41b, 42a, 42b.
As the material of the heat absorbing electrodes 40a to 42b, a material having a higher thermal conductivity than that of the insulator sheet 32, for example, A
g, Pd, Cu or the like is used. Endothermic electrodes 40a-42
b may be formed by applying a paste of Ag, Pd, Cu or the like on the surface of the insulator sheet 32 by means of screen printing and drying, or by means such as sputtering or vapor deposition. .

One end 33a of the coil conductor 33 is exposed on the left side of the insulator sheet 32. Coil conductor 3
One end portion 36 a of 6 is exposed on the right side of the insulator sheet 32. The heat absorbing electrodes 40a, 41a, 42a are partially exposed at the front side of the insulating sheet 32, and
Part of 0b, 41b, 42b is exposed at the back side of the insulator sheet 32. Semicircular notches 43 are formed in the heat absorbing electrodes 40a to 42b in order to avoid via holes.

Coil conductors 33 to 36 and heat absorbing electrode 40
An insulating sheet 32 having a to 42b provided on the surface and a protective insulating sheet (not shown) having no surface provided on the surface are stacked, molded, and fired to form a laminated body 31.
In the laminated state, the coil conductors 33 to 36 are provided with via holes 45 and 4 provided in the insulator sheet 32, respectively.
6, 47, 48, 49 and 50 are electrically connected in series to form a coil 38. And the heat absorbing electrode 40a
42b are arranged close to the coil conductors 33 to 36.

As shown in FIG. 7, a molded laminate 31 is formed.
Has input / output electrodes 52 and 53 at both ends thereof, and a heat radiation electrode 54 wound around the center thereof. The input / output electrode 52 is electrically connected to the end 33a of the coil conductor 33, the input / output electrode 53 is electrically connected to the end 36a of the coil conductor 36, and the heat dissipation electrode 54 is the heat absorbing electrodes 40a to 42.
connected to b. This laminated inductor has a coil 38
When a current flows through the coil 38, the heat generated in the coil 38 is transferred to the heat absorbing electrodes 40a to 42b through the insulator. Heat absorbing electrode 40
a to 42b efficiently transfer the transferred heat to the heat dissipation electrode 54. Further, the heat dissipation electrode 54 dissipates the transferred heat in the air or in the conductive path of the printed wiring board on which the laminated inductor is mounted, and suppresses the temperature rise of the laminated inductor. As a result, it is possible to obtain a laminated inductor capable of setting a large rated current.

[Other Embodiments] The laminated inductor according to the present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the invention. The shape, position and quantity of the heat dissipation electrode and the heat absorption electrode are selected in accordance with the specifications of the laminated inductor. The heat dissipation electrode is
It goes without saying that the larger the surface area, the better the heat dissipation effect.

In the laminated inductor of each of the above-mentioned embodiments, the insulating sheets are stacked and then integrally fired, but the invention is not necessarily limited to this. For example, you may manufacture a laminated body by the manufacturing method demonstrated below. After applying an insulating material in paste form and drying it to form an insulating material, a conductor material for coil or a heat absorbing electrode material in paste form is applied to the surface of the insulating material film and dried to form a conductor for coil. Or forming a heat absorbing electrode. In this way, a laminated body is formed by sequentially applying the layers, and then integrally fired.

[0019]

As is apparent from the above description, according to the present invention, since the heat dissipation electrode is provided on the surface of the laminated body, the heat generated in the coil constituted by the coil conductor is transmitted through the insulator. Is conducted to the heat radiating electrode, and is further radiated from the heat radiating electrode into the air or a conductive path such as a printed wiring board on which the laminated inductor is mounted. Therefore, it is possible to obtain the laminated inductor in which the temperature rise of the laminated inductor is suppressed and a large rated current can be set.

Further, when a current is applied to the coil, the temperature rise can be suppressed as compared with the conventional laminated inductor, so that the electrical and mechanical reliability of the laminated inductor is improved. Further, by providing the heat absorbing electrode inside the laminated body, the heat generated in the coil is efficiently conducted from the heat absorbing electrode to the heat radiating electrode through the insulator, and the temperature rise of the laminated inductor can be further suppressed.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing the appearance of the laminated inductor shown in FIG.

FIG. 3 is an electrical equivalent circuit diagram of the multilayer inductor shown in FIG.

FIG. 4 is a perspective view showing a mounted state of the laminated inductor shown in FIG.

5 is a perspective view showing another mounting state of the laminated inductor shown in FIG.

FIG. 6 is an exploded perspective view showing a second embodiment of the laminated inductor according to the present invention.

FIG. 7 is a perspective view showing the external appearance of the laminated inductor shown in FIG.

FIG. 8 is a perspective view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Insulator sheet 3-7 ... Coil conductor 8 ... Coil 16, 17 ... Input / output electrodes 18a, 18b ... Heat dissipation electrode 31 ... Laminated body 32 ... Insulator sheet 33-36 ... Coil conductor 38 ... Coils 40a to 42b ... Heat absorption electrodes 52, 53 ... Input / output electrodes 54 ... Radiation electrodes

Claims (2)

[Claims] 1. A laminated body formed by stacking an insulator and a coil conductor, and an input / output electrode provided on a surface of the laminated body and electrically connected to a coil formed of the coil conductor. A heat dissipation electrode that is provided on the surface of the laminated body and is not connected to any conductor, and a laminated inductor. 2. A laminated body formed by stacking an insulator, a conductor for a coil and a heat absorbing electrode, and an input electrically connected to the coil formed by the conductor for the coil provided on the surface of the laminated body. A multilayer inductor comprising: an output electrode; and a heat dissipation electrode provided on a surface of the multilayer body and connected to the heat absorption electrode.