JPH01199417A - Inductance element - Google Patents

Abstract

PURPOSE:To obtain winding type thin element of small size equal to a C and R chip by a method wherein a coil is formed by winding a copper wire on the winding groove of a square-shaped core, a heat-resisting film is fixed to the end face having the winding groove of the square-shaped core, and a pair of electrodes which are electrically connected to the lead part of the coil are provided on the end face opposing to the square-shaped core. CONSTITUTION:A coil 2 is formed by winding a copper wire on the winding groove 5 of a square-shaped core 1, a heat-resisting film 3 is wound and fixed on the end face having the winding groove 5 of the square-shaped core 1, and a pair of electrodes 4a and 4b, which are electrically connected to the lead part of the coil 2, are provided on the end face opposed by the end face having the above-mentioned winding groove 5. For example, a coil 2 is provided by winding a copper wire in the prescribed number of turns on the winding groove 5 provided on the end face of the square-shaped core 1. After a heatproof film 3 of polyester, polyimide and the like, on one surface of which a thermosetting bonding agent was coated in advance, has been wound, the film 3 is adhered to the square-shaped core 1 by heating. Then, the pair of electrodes 4a and 4b, which are electrically connected to the lead part of the coil 2, are provided in such a manner that one end of the metal plate terminal, which is bent in L-shape, is fixed to the bottom face of the square-shaped core 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to inductance elements used in electronic circuits in various fields such as video and television, and particularly in recent years in high-density packaging,
The present invention provides a small and thin inductance element suitable for surface mounting.

2. Description of the Related Art A conventional inductance element having a structure as shown in FIG. 4 is well known. In FIG. 4, 41 is a drum core, and generally a sintered body of Ni--Zn ferrite is used. 42 is a coil, and the drum core 41 is wound with a copper wire having a diameter of 30 to 60 μm. The drum core 41 provided with the fill 42 is fixed to metal plate terminals 44a and 44b, and the lead portion (not shown) of the coil 42 is connected to the metal plate terminal 44! L and 44b, respectively.

43 is resin, and the drum core 41. Coil 42 and metal plate terminal 44! Parts of L and 44b are integrally molded.

The conventional inductance element, which has a configuration that exceeds the problem to be solved by the invention, has characteristics such as a high Q and a large inductance because it is a wound wire, and can be mass-produced at a relatively low cost, so it is suitable for surface mounting. It has become the mainstream inductance element for applications.

However, due to manufacturing constraints of the drum core 41, which is mainly made of sintered ferrite, it has been difficult to make it smaller and thinner than C9H chip parts.

The present invention eliminates the drawbacks of the conventional inductance element and provides a small and thin inductance element that is wound and comparable to C and H chip components.

Means for Solving the Problems In order to solve the above problems, the inductance element of the present invention has a coil formed by winding copper wire around the winding grooves of a square core, and a heat-resistant film wrapped around the end face of the square core having the winding grooves. A pair of electrodes are provided on opposite end faces of the square core, each electrically connected to the lead portion of the coil.The J-type structure is used to reduce the size and thickness of the coil.

The present invention, which has more than just functions, does not use molding resin and uses the rectangular core itself as the main body of the inductance element, thereby making it compact without making the core smaller.

By reducing the thickness of the rectangular core and wrapping and fixing a heat-resistant film around the end face of the rectangular core having the winding groove, the coil provided in the winding groove can be protected from the heat received when the inductance element is mounted.
i.e. solder dip.

(Infrared) Protects from reflow heat and improves reliability.

Example The present invention will be explained in detail below based on examples.

FIG. 1 is a perspective view showing one embodiment of the inductance element of the present invention, and FIG. 2 is a sectional view taken along the line AA' in FIG. 1. In both figures, 1 is a rectangular core, and a coil 2 is provided by winding a copper wire a predetermined number of times in a winding groove 5 provided on the end face of the core. 3 is a heat-resistant film made of polyester, polyimide, etc. that is wrapped around and fixed to the end face of the square core 1. A thermosetting adhesive is applied in advance to the surface in contact with the square core 1. , and is fixed to the square core 1 by heating. 4a and 4b are a pair of electrodes electrically connected to the lead part (not shown) of the coil 2; in this embodiment, one end of a metal plate bent into an L shape is fixed to the lower surface of the square core 1. It was established.

In this embodiment having the above-described configuration, by using the rectangular core 1 itself as the main body of the inductance element without using molding resin, it is possible to significantly reduce the size and thickness compared to the conventional one.

To give an example of a specific numerical value, the required wall thickness of the molding resin is generally 0.3 ff or more, and if it is less than this, unfilling will occur. Therefore, simply by not using resin molding, the thickness of the inductance element can be reduced by 0.6 ff or more. In this embodiment, the dimensions of 3,2.times.1.6(b)Xl,1(t)-, which are comparable to C and H chip components, are realized. The minimum dimensions of a conventional wound wire inductance element are 3.2 (AX 2.5 (W) x 2.
2(t)-, a small and thin inductance element with a thickness of 'V21 and a volume of less than Akira can be realized.

In addition, by fixing the heat-resistant film 3 to the end face of the square core 1, the heat applied to the coil 2 is reduced, and accidents such as layer shorts are prevented, and flux during soldering is prevented from adhering to the coil 2. This prevents deterioration of characteristics such as a decrease in self-resonant frequency and greatly improves reliability.

Note that if a sintered ferrite body is used as the square core 1, an inductance element with a large inductance and Q can be realized. Furthermore, when non-magnetic ceramics such as alumina are used, the inductance is small but the frequency characteristics are improved, making it possible to realize an inductance element for high-frequency circuits.

FIG. 3 shows a sectional view of another embodiment of the invention.

The constituent elements of this embodiment are the same as those of the previous embodiment, so their explanation will be omitted.

The feature of this embodiment is that the square core 1 is made of resin containing magnetic material.
As shown in the figure, the electrodes 4a and ab can be embedded in the rectangular core 1, and the fixation between them becomes strong. Further, the electrodes 4a and 4b are made of metal plates,
A plurality of these are connected to form a hoop terminal, and the rectangular core 1 can be fixed to the hoop terminal continuously and at high speed by molding, thereby reducing the number of man-hours and material costs.

As the magnetic material contained in the resin, ferrite powder, amorphous powder, etc. can be used.

However, the desired frequency characteristics can be easily achieved by using a mixture of two or more magnetic materials, such as mixing ferrite powder and amorphous powder at a predetermined ratio.

Effects of the Invention As described above, the present invention provides a small and thin inductance element which is thinner than conventional inductance elements and smaller in volume than conventional inductance elements. This will further promote implementation and greatly contribute to making electronic devices smaller and thinner.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a sectional view showing one embodiment of the inductance element of the present invention, FIG. 3 is a sectional view showing another embodiment, and FIG. 4 is a sectional view showing a conventional inductance element. It is. 1... Square core, 2... Coil, 3...
...Heat-resistant film, 4! L, 4b... Electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure l Square core Figure 2 Square core ＼ 41 Eye

Claims (3)

[Claims] (1) Copper wire is wound around the winding groove of a square core to form a coil, a heat-resistant film is wound around and fixed to the end face of the square core having the winding groove, and the end face opposite to the end face having the winding groove is An inductance element with a pair of electrodes each electrically connected to the lead part of a coil. (2) The inductance element according to claim 1, wherein the square core is made of ferrite or non-magnetic ceramic. (3) Claim 1 in which the square core is made of a resin containing a magnetic substance.
The inductance element described.