JPS5848410A - Manufacture of inductor - Google Patents

Abstract

PURPOSE:To obtain an inductor with a simple process, good mass productivity, easy adjustment of inductance and a few occurrence of trouble at the timing of dipping solder by a method wherein a long winding inductor bar coated a magnetic substance on the circumference of the bar is cut. CONSTITUTION:AgPd alloy wire 7 coated by magnetic substance or coating containing ceramic is wound on a magnetic substance bar 6. At rough winding sections 81 the conductor is bared and AgPd alloy paste 9 is applied on the rough winding sections 81 and dried. Magnetic substance paste is coated on the circumference of the winding magnetic substance bar and is burned for two hours at 900 deg.C and the obtained long inductor bar 10 is cut at the center of the rough winding sections. AgPd paste is applied to the AgPd wires of the obtained inductor element pieces 11 both sectional faces exposed internal electrodes 12 for burning and external electrodes are formed. This method is a winding system. Therefore, arbitrary inductance is obtained without any trouble on process and high inductance is possible.

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing an inductor.

There are two types of inductors: an air-core type in which a wire is wound around a non-magnetic support, and a core-type inductor in which a wire is wound around a magnetic core. In either case, the conductor to be wound is enamel or formal to ensure electrical insulation between the wires.

A coating made of polymeric resin such as polyurethane or polyimide is applied. In recent years, with the miniaturization of electronic circuits, there has been a demand for smaller electronic components, and resistors, capacitors, and transistors are rapidly being made into chips. However, the introduction of inductors into chips has been delayed, and The situation is such that there is a strong desire for this to become a reality. Furthermore, as problems specific to inductors, electronic circuits become more complex, and when chip-type inductors are densely packaged with other electronic components, electromagnetic noise from the outside or inside increases, interfering with normal operation. or the magnetism from the inductor may adversely affect other circuits. For this reason, chip-type inductors are of a closed magnetic circuit type in which the winding is surrounded by a magnetic material and the external magnetic material and the magnetic core are magnetically coupled to prevent magnetic lines of force from leaking outside. I'm looking forward to that.

Broadly speaking, two types of such chip-type inductors have been proposed. One of them is shown in cross section in FIG. 1, in which a polyurethane wire 2 is wound around a magnetic core 1, and the terminal 4 of the winding inserted into a magnetic body 3 is connected to an external electrode 5. The external electrode is a conductive material. In this type of inductor, the inductance can be easily adjusted by adjusting the number of winding turns, and the process is simple. Wire connections tend to become flattened and defects are likely to occur. Furthermore, since there is a limit to the reduction in the molding dimensions of the magnetic body 3, there are problems such as an increase in the size of the inductor.

41. -... On the other hand, a thin chip inductor has been proposed in which a coil-shaped conductive pattern is formed on a magnetic sheet, which are successively laminated and then sintered and integrated. This method is very effective for downsizing the inductor, but in order to increase the inductance, the number of coil turns must be several 1.
In order to make zero turns, there are problems in that the number of laminated layers is extremely large, the process becomes complicated, and the shape becomes large. Another problem is that it becomes complicated to change the lamination method in order to obtain products with the same shape but different inductance.

The present invention eliminates such conventional problems, has a simple process, is highly suitable for mass production, and allows easy adjustment of inductance.
Furthermore, the present invention provides an inductor manufacturing method that causes fewer troubles in the solder depth.

The manufacturing method of the present invention includes the steps of winding a conductive wire around a magnetic bar so that coarse winding portions and dense winding portions are alternately and continuously arranged; The conductor wire ′ is a bare wire, and the process involves coating the magnetic material around the magnetic bar so that a firing groove is buried in the bare wire portion, and firing the magnetic material to form a long inductor bar. During the process, the long inductor no(-
This method is characterized by comprising the steps of cutting the inductor into individual inductor pieces, and forming external electrodes at both ends of the inductor pieces.

Examples of the present invention will be specifically described below.

First, a magnetic material (-6) as shown in FIG. 2 is prepared.

This magnetic bar 6 is made of ferrite powder (F in this example).
e2es, whose main components are NiO and ZnO) was compression molded and then fired. Thickness is 0.1×1.5mnf
Its cross section is 3 cm long.

Next, as shown in FIG.
Wind from one end to the other end. Here, the conductor 7 has a cross-sectional configuration of 86 pieces g-1 with a diameter of 60 μΦ as shown in FIG.
A magnetic material-containing layer 72 is formed on the outer periphery of a 5% Pd alloy wire 71, and a polyester resin film 73 is further formed. Here, magnetic 3.3 di-n-butyl thiphthalate + 90
A paste prepared by adding 60% of ferrite powder to a vehicle of % chilpinol and kneading was mixed well with 20% of a 46% solution of polyisocyanate in ethyl acetate, which was coated and dried. The conductive wire 7 is continuously wound around the magnetic bar 6 toward the other end, and the winding density is such that coarse winding portions 81 and dense winding portions 82 are arranged alternately. Do it like this. This densely wound portion 82 may be an overlapping winding, and the number of turns is determined depending on the required inductance value.

The width of the coarse winding portion 81 must be wider than the thickness of the cutter blade used in the subsequent cutting process, and the number of windings may be 1 to 2 turns. In addition, it is necessary that the conducting wire 7 is a bare wire consisting only of the alloy wire 71 from which the magnetic material-containing layer and the polyester resin film have been peeled off in this rough portion.

Next, as shown in FIG. 6, a commercially available mug-Pd alloy paste 9 for firing (to become an internal electrode) was applied onto the alloy wire 71 of the coarsely wound portion 81 and dried.

If fired at a temperature that does not cause sintering, the strength will be weak;
It may break during winding. Therefore, the manufacturing method of the present invention can be more perfected by setting the firing temperature of the magnetic bar to a temperature range that is 20"C or more lower than the firing temperature after ferrite coating and higher than the ferrite sintering start temperature.

In addition, although a ferrite-containing coated wire was used as the conductor 7 in the above example, it is also possible to use a wire coated with a paste made by kneading ferrite powder and alumina powder with a vehicle, or a wire coated with a silica/alumina ceramic coated wire with a silicone face. Even if an inductor was manufactured using an inductor soaked in the inductor, an inductor having the same characteristics as the above example was obtained.

In particular, when using a magnetic bar or ferrite coating having a composition with low electrical insulation, it is necessary to use a ceramic-containing coated wire. Moreover, a face such as enamel or formal may be used instead of the polyester resin film.

Further, as the external electrode, although muggPd fired paste was used in the above embodiment, other electrodes used for external electrodes may be used.

As is clear from the above description, according to the present invention, since the present invention is basically a winding method in which a conductor is wound to form a coil, it is easy to select the number of turns, and therefore it is possible to obtain an inductance of any desired value. There is no process complexity, and
It is also possible to obtain high inductance by employing multilayer windings. Furthermore, by using conductive wires coated with magnetic or ceramic material, the insulation between the wires will not be damaged even by high temperature firing. Furthermore, when obtaining high inductance, it has the advantage that the process is extremely simple compared to the conventional method of forming a conductor by printing, and its industrial value is great.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional inductor, and FIGS. 2, 3, 4, 5, 6, 7, and 8 are inductor manufacturing methods according to the present invention. It is a figure for explaining each process. Line, 72... Layer containing at least one of magnetic material and ferrite, 73... Resin film, 81
...Coarse winding part, 82...Dense winding part, 9... Conductive heath for firing, 104 scale inductor bar, 11... Inductor piece, 12.
...Internal electrode, 13...External electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) A conductor wire is wound around the magnetic bar so that the part corresponding to the coarse winding part is bare wire, and the coarse winding part and the dense winding part are arranged continuously and alternately. a step of applying a conductive paste for firing including the conductive wire to the coarse winding portion in a flat manner and drying it; and a step of coating the magnetic material around the magnetic bar so as to bury the conductive wire. , the step of firing the magnetic bar to form a long inductor bar, and cutting the long inductor bar at the center of the rough windings or at the center of the winding to form individual inductor pieces. A method for manufacturing an inductor, comprising the steps of: forming external electrodes on both ends of the inductor piece. (2. Claim No. (12) A method for manufacturing an inductor, characterized in that the magnetic material is ferrite. A method of manufacturing an inductor.