JPH10106876A - Manufacture of coil components - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing coil components which is excellent in productivity and has high yield. SOLUTION: A conical or pyramidal hollow part 1a is formed in the central part of an outside insulator 1 having a stepped slant 1b is formed. The inner surface of the hollow part 1a is constituted of a plurality of turns. On the slant surface 1b, the diameter of each turn part is positioned in a gradually different plane from one end to the other end. Conductor 2 is formed on the inner surface of the hollow part 1a of the outside insulator 1 of a hollow body type, and cut out at corner parts of the stepped slant. This method of manufacturing coil components is excellent in productivity and can realize high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a coil component used for various electronic devices and communication devices.

[0002]

2. Description of the Related Art Coil components are widely used as coils and transformers for various electronic devices and communication devices. In recent years, there has been an increasing demand for small or thin coil components. Accordingly, the importance of coil components as noise suppression components is increasing.

As a conventional coil component satisfying these demands, a laminated coil component obtained by alternately laminating ferrite magnetic layers and coil conductors (for example, Japanese Patent Publication No. Sho 57-3)
9521).

[0004]

In order to obtain a coil component having a large inductance value, it is necessary to increase the number of turns of the conductor pattern in the above-mentioned laminated coil component, and an extremely large number of ferrite layers and conductor patterns are laminated and printed. It is necessary, and the number of man-hours increases, and there is a problem in productivity.

An object of the present invention is to provide a method of manufacturing a coil component which eliminates the above-mentioned conventional drawbacks, is excellent in productivity, and has an excellent yield.

[0006]

In order to solve the above-mentioned problems, a method of manufacturing a coil component according to the present invention is characterized in that a hollow inner surface of an outer insulator provided with a conical or pyramid-shaped hollow portion at the center has a plurality of turns. A step of forming an outer insulator having a step-like slope gradually located in different planes from one end to the other end, and a conductor on the inner surface of the hollow portion of the hollow outer insulator. And a step of cutting the conductor at the corners of the step-shaped slope.

According to the present invention, a coil component having excellent productivity and excellent yield can be obtained.

[0008]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, a hollow inner surface of an outer insulator provided with a conical or pyramid-shaped hollow portion at the center is formed of a plurality of turns, and each turn portion has a diameter. Forming an outer insulator having a step-like slope gradually located in a different plane from one end to the other end, and forming a conductor on the inner surface of the hollow portion of the hollow outer insulator, This is a method including a step of cutting a conductor at a corner of a step-like slope, and a coil component can be manufactured with excellent productivity.

According to a second aspect of the present invention, the hardness of the outer insulator is greater than the hardness of the conductor, so that the cutability of the conductor can be improved, and a short circuit between adjacent step-shaped slopes of the conductor can be eliminated. Coil components can be manufactured with excellent yield.

According to a third aspect of the present invention, the step of cutting the conductor at the corners of the step-like slope includes forming a conical or pyramidal mold having substantially the same shape as the conical or pyramid-shaped hollow portion of the outer insulator. This is a method of cutting a conductor by pushing it in. A short circuit between adjacent step-shaped slopes of the conductor is eliminated, and a coil component can be manufactured with excellent yield.

According to a fourth aspect of the present invention, in the step of cutting the conductor at the corners of the step-like slope, the core insulator having substantially the same shape as the conical or pyramid-shaped hollow portion of the outer insulator is pressed. This is a method of cutting a conductor, and a coil component can be manufactured with an excellent yield by eliminating a short circuit between adjacent step-shaped slopes of a conductor at the same time as forming an insulator layer on a core.

According to a fifth aspect of the present invention, the hardness of the core insulator is made larger than the hardness of the conductor, so that the cutability of the conductor can be improved, and a short circuit between adjacent step-shaped slopes of the conductor can be prevented. Coil components can be manufactured with excellent yield.

According to a sixth aspect of the present invention, the hardness of the outer insulator is greater than the hardness of the conductor, and the hardness of the core insulator is greater than the hardness of the conductor. In addition, a coil component can be manufactured with an excellent yield by eliminating a short circuit between adjacent step-shaped slopes of a conductor.

According to a seventh aspect of the present invention, there is provided a method of cutting a conductor by pressing a rotating body having a ground surface against a corner of a step-like slope, and eliminating a short circuit between adjacent step-like slopes of the conductor. Coil components can be manufactured with a high yield.

In the invention according to claim 8, the step of cutting the conductor at the corner of the step-like slope is a method of cutting the conductor using a laser, and it is excellent in eliminating a short circuit between adjacent step-like slopes of the conductor. Coil components can be manufactured with a high yield.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, FIG. 1 is a perspective view schematically showing a typical example of a coil component obtained by the method for manufacturing a coil component of the present invention. That is, as the conductor 2 formed on the inner surface of the hollow outer insulator 1 having a conical (or pyramid) hollow portion provided at the center, the diameter gradually increases from one end to the other end, and the positions are all different. It has a three-dimensional spiral shape located in a plane.

At the center of the outer insulator 1 having the conductor 2, there is provided a core insulator 7 having substantially the same size as the conical (or pyramid) hollow portion of the outer insulator 1. . That is, the conductor 2 is surrounded by the outer insulator 1 and the core insulator 7.

Leaders 3 and 4 are provided at both ends of the conductor 2, and the leads 3 and 4 are connected to end face electrodes 5 and 6 provided at both ends of the outer insulator 1.

FIG. 2 is a sectional view of a coil component obtained by the manufacturing method of the present invention shown in FIG.
Has a structure formed on a stepped slope 1b of a hollow portion 1a on the inner surface of a hollow outer insulator 1. Here, the outer insulator 1, the core insulator 7, the upper magnetic body 8 or the lower magnetic body 9 are made of one kind of material or different materials, and these insulators are non-magnetic or magnetic. There may be.

Any non-magnetic material may be used as long as it is electrically insulating, such as an organic insulating material such as glass epoxy or polyimide, or an inorganic insulating material such as glass, glass ceramic or ceramics. The magnetic material may be a ferrite material having a generally high magnetic permeability, such as a NiZn-based or NiZnCu-based material.

When the outer insulator 1 or the core insulator 7 is made of a magnetic material, the inductance value can be increased. When the outer insulator 1 or the core insulator 7 is made of a non-magnetic material, a large inductance value cannot be obtained. As a result, the usable frequency band becomes wider.

Further, each of the outer insulator 1, the core insulator 7, the upper magnetic body 8 and the lower magnetic body 9 does not need to be made of one kind of insulating material. By combining more than one kind of insulating material, the electrical characteristics of the coil component obtained by the manufacturing method of the present invention can be freely controlled. For example, it becomes possible to adjust the inductance and the DC superimposition characteristic, take measures against the leakage magnetic flux, and control the usable frequency band.

Any material may be used as the material of the conductor 2 or the lead portions 3 and 4 as long as it is an electrically good conductor. However, since the coil component is required to have low resistivity, copper, silver or silver and palladium alloy are required. Conductive materials such as are effective.

The end electrodes 5 and 6 may be made of a conductive material. However, in general, the end electrodes 5 and 6 are preferably composed of a plurality of layers instead of a single layer. It is necessary to consider the mounting strength, solder wettability during mounting, solder erosion, etc. Specifically, the lowermost layer uses the same conductive material as the lead portions 3 and 4, and the middle layer has resistance to solder Is used, and solder or tin having good wettability to solder is used for the outermost layer.
However, this is only an example, and it is not always necessary to employ these, and a conductive resin material may be included in addition to a material having excellent conductivity such as a metal.

Further, as shown in FIG.
Although FIG. 1 shows one formed by a circular turn portion, a prismatic shape is originally preferred as a surface mount type coil component. In a prismatic coil component, a conductor is formed by a square turn portion. By forming, the coil pattern can be formed over the entire outer diameter of the coil component.

As described above, the coil component obtained by the manufacturing method of the present invention centering on an example of the pattern of the conductor 2,
Since the conductor 2 is continuously formed on a virtual conical or pyramid-shaped stepped slope in the insulator, productivity can be improved unlike the conventional laminating method. Also,
In the coil component obtained by such a manufacturing method, since the neighboring turn portions do not face each other via the insulator, the generation of stray capacitance is minimized, and the self-resonant frequency is reduced, so that the coil component is used as a filter. In such a case, it is possible to prevent a high attenuation from being obtained in a wide band, and it is possible to obtain a coil component excellent in quality and performance.

In the above embodiment, only the surface mounting type having end electrodes 5 and 6 at both ends has been described. However, instead of a terminal having a pin terminal implanted on an insulator or a terminal electrode. It is also possible to obtain a lead-type coil component in which cap-shaped electrodes having terminals are connected to both ends of an insulator.

Next, a method of manufacturing a coil component according to the present invention will be described. In the method for manufacturing a coil component according to the present invention, the hollow inner surface of the outer insulator provided with a conical or pyramid-shaped hollow portion in the center has a plurality of turns, and the diameter of each turn portion gradually varies from one end to the other end. Forming an outer insulator having a stepped slope located in a plane, forming a conductor on the inner surface of the hollow portion of the hollow outer insulator, and forming the conductor at a corner of the stepped slope. This is a method having a cutting step.

Next, a more detailed manufacturing method of the present invention will be described with reference to the drawings.

4 to 10 are sectional views showing a method of manufacturing a coil component according to the present invention in the order of steps.

First, as shown in FIG. 4, on the inner surface of a hollow outer insulator 1 having a conical or pyramid-shaped hollow portion 1a formed at the center, a three-dimensional spiral-shaped step portion as a step-like slope is provided. 1b, and the conductor 2 is formed on the stair portion 1b so that the conductor 2 is formed such that it has a plurality of turns, and the diameter of each turn portion gradually changes from one end to the other end, and at least each turn portion is located in a different plane. An outer insulator 1 having an inner surface as possible is formed.

As a method of forming the hollow outer insulator 1 having the inner surface having the above-mentioned shape, a slurry-like outer insulating material is flowed on a support having a convex portion capable of meshing with the inner surface, and the slurry is dried. Later, by separating from the support, a predetermined hollow portion 1a can be formed in the outer insulator 1. As another method, as described above, a slurry-like outer insulating material is poured onto a flat support to form a flat sheet-like outer insulator 1, and then the above-described predetermined hollow portion 1 is formed.
In this method, a predetermined hollow portion 1a is formed in the outer insulator 1 by using a mold having a shape for forming a. Further, the hollow outer insulator 1 having the predetermined hollow portion 1a can be similarly formed by a generally known powder molding method.

Next, as shown in FIG.
The conductor 2 is formed on the inner surface of the three-dimensional spiral-shaped stepped portion 1b of the hollow portion 1a of the outer insulator 1 having the following. The conductor 2 has a plurality of turns, and the diameter of each turn portion gradually changes from one end to the other end, and at least each turn portion is located in a different plane. As its shape, as described above, the conductor 2 in the form of a mosquito coil is pulled down to form a trumpet shape.

The conductor 2 is formed by suction printing from the surface opposite to the printing surface of the outer insulator 1 or by spraying the conductor in the same manner as through hole printing generally known using a conductor paste and a printing machine. A plurality of turns are formed on the inner surface of the outer insulator 1, and the diameter of each turn portion is gradually changed from one end to the other end, and at least each turn portion is formed so as to be located in a different plane.

However, in this step, the conductor may be short-circuited on the three-dimensional spirally-shaped stepped portion 1b in which the conductor is formed to be in contact with the conductor on the adjacent stepped portion 1b. Is in a low state.

Then, as shown in FIG. 6, the conductor 2 formed in the preceding step is cut at the corners of the three-dimensional spirally-shaped stepped portion 1b of the outer insulator 1, and the three-dimensional spirally-shaped stepped portion is cut. 1b
Is formed along the conductor pattern. As a method of cutting the conductor 2 at the corners of the three-dimensional spiral-shaped step portion 1b of the outer insulator 1, a cone or a pyramid having substantially the same shape as the conical or pyramid-shaped hollow portion 1a of the outer insulator 1 is used. The conductor 2 is cut at the same time as the formation of the core insulator 7 by a method of pressing the mold and cutting the conductor 2 and a method of pressing the insulator having substantially the same shape as the conical or pyramid-shaped hollow portion 1a of the outer insulator 1. A method of cutting the conductor 2 by pressing a rotating body having a ground surface against the corner of the three-dimensional spirally-shaped stepped portion 1b, or a method of cutting the conductor 2 using a laser is used. With these methods, a short circuit of the conductor 2 can be eliminated, and a complete coil component can be manufactured with excellent yield.

Here, in order to realize good cutting of the conductor 2, the hardness of the outer insulator 1 is required to be larger than the hardness of the conductor 2. In addition, when the method of cutting the conductor 2 at the same time as the formation of the core insulator 7 by using a method of forcing an insulator having substantially the same shape as the conical or pyramid-shaped hollow portion 1a of the outer insulator 1, good cutting is performed. In order to realize this, the hardness of the core insulator 7 is required to be greater than the hardness of the conductor 2, the hardness of the outer insulator 1 is greater than the hardness of the conductor 2, and the hardness of the core insulator 7 is The hardness of the conductor 2 is required to be higher.

Next, as shown in FIG. 7, a lower magnetic member having a lead-out portion 3 formed on the bottom surface of the outer insulator 1 on which the conductor 2 is formed so as to be joined to the conductor end of the conductor 2 on the side where the conductor diameter is smaller. Joint with the body 9.

Next, as shown in FIG. 8, the core insulator 7 is filled in the hollow portion formed by the outer insulator 1 and the lower magnetic body 9. This step can be omitted in the case of using a method of cutting the conductor 2 by pressing the insulator.

Next, as shown in FIG. 9, the conductor 2 is placed on the bottom surface of the outer insulator 1 and the opposite surface where the lead-out portion 3 is formed in the same manner as described above.
Is joined to the upper magnetic body 8 having the lead portion 4 joined to the conductor end on the side with the larger conductor diameter.

Further, as shown in FIG. 10, end surface electrodes 5 and 6 are formed on two surfaces of the chip-shaped coil component. By firing the obtained laminate, a coil component can be obtained. However, baking may be performed without forming the end face electrodes 5 and 6. That is, the electrode without the end face electrodes 5 and 6 is fired, and the end face electrodes 5 and 6 are formed after firing. An example of a formation method in this case will be described. A conductor layer is formed in the same shape as the end face electrode shown in FIG. 10 and fired. Thereafter, nickel plating and solder or tin plating are performed using the conductor layer as an electrode. Eventually, the end face electrodes 5 and 6 have a three-layer structure of a base conductor layer formed by firing and nickel and solder or tin plating formed by electroplating.

The outer insulator 1, the core insulator 7, the upper magnetic body 8 or the lower magnetic body 9 are formed by a generally known green sheet forming method, printing method, dipping method, powder molding method, spin coating method or the like. Can be formed. The conductor 2 or the lead portions 3 and 4 are generally printed, but may be sprayed, dripped or potted.

In the examples shown in FIGS. 5 to 10, the hollow insulator, that is, the outer insulator 1 and the solid insulator, that is, the end face located so as to be in contact with the core insulator 7, respectively. Although the method of forming the insulating layer, that is, the upper magnetic body 8 and the lower magnetic body 9 has been described, only one of the upper magnetic body 8 and the lower magnetic body 9 may be formed. The electrical characteristics of the coil component obtained when only one of them is formed include the outer insulator 1, the core insulator 7, and the upper magnetic body 8
Alternatively, if the lower magnetic body 9 is a magnetic body, it becomes smaller because it does not have a completely closed magnetic circuit configuration, but the DC superposition characteristics become better.

The paste for forming each of the above layers is as follows:
Each powder and butyl carbitol, terpineol and alcohols, ketones, solvents such as acetates, ethyl cellulose, polyvinyl alcohol, binders such as polyvinyl butyral, further, sintering aids such as various oxides or glasses, Plasticizers such as phthalates and glycerin and various dispersants may be added. Each layer is formed using a kneaded material obtained by mixing these. These are laminated in a predetermined structure as described above and fired to obtain a coil component.

The firing temperature range is from about 800 ° C. to 1
It is in the range of 300 ° C. In particular, the firing temperature differs depending on the conductor material used. For example, when silver is used, it is necessary to be about 900 ° C., and for an alloy of silver and palladium, it is about 950 ° C., and for nickel and palladium, firing is performed at a high temperature.

Next, more specific embodiments of the present invention will be described. Example 1 A ferrite slurry was prepared by mixing 8 g of polyvinyl butyral resin, 4 g of dibutyl phthalate, and 50 g of n-butyl acetate with 100 g of NiZnCu-based ferrite powder and kneading them using a pot mill. This slurry was applied on a PET film by a doctor blade method to prepare a ferrite green sheet having a dry film thickness of 0.2 mm.

The three ferrite green sheets are stacked and heated at a pressure of 300 kg using a hot press set at 85 ° C.
/ Cm ² for 5 seconds to produce a laminate. This laminate has a plurality of turns on the inner surface of a hollow insulator as shown in FIG. 4, and the diameter of each turn portion gradually changes from one end to the other end, and at least each turn portion is located in a different plane. Then, a mold having a shape for forming the conductor 2 was mounted on a puncher and pressed into a laminate to form an outer insulator 1 having a predetermined inner surface.

Next, as shown in FIG. 5, using a commercially available silver paste and a printing machine, the diameter of each turn portion is gradually changed from one end to the other end so that at least each turn portion is located in a different plane. Conductor 2 was formed. The printing method was such that the silver paste was sucked from the opposite side of the printed surface of the outer insulator 1 and the silver paste was left on the stepped slope on the inner surface, similarly to the generally known through-hole printing.

Next, as shown in FIG. 6, a conical mold having substantially the same shape as the conical hollow portion of the outer insulator 1 is pressed, and the conductor 2 formed in the previous step is wound three-dimensionally around the outer insulator 1. It was cut at the corner of the step-like portion 1b.

Next, as shown in FIG. 7, a lead-out portion 3 was formed on the ferrite green sheet prepared above using the same silver paste and printing machine as described above. That is, the extraction portion 3 was formed in the lower magnetic body 9. Furthermore, the lower insulator 9 and the outer insulator 1 on which the conductor 2 was formed were bonded.

Further, as shown in FIG.
Then, a ferrite slurry was poured into the cavity on the inner surface of the substrate, and filled and flattened to form a core insulator 7.

Next, as shown in FIG. 9, the lead portion 4 is formed on the ferrite green sheet previously prepared in the same manner as described above, and the outer insulator 1, the core insulator 7, and the lower magnetic body having the conductor 2 built therein are provided. 9 was laminated by a lamination press as shown in the figure. Thereafter, end electrodes 5 and 6 as shown in FIG. 10 were formed using a commercially available silver paste, and fired under the condition of holding at 900 ° C. for 2 hours to obtain a coil component.

(Example 2) As a method of cutting the conductor 2 at the corners of the three-dimensional spiral-shaped step portion 1b of the outer insulator 1, a method of cutting the conductor 2 into a shape substantially the same as the conical hollow portion of the outer insulator 1 is used. Example 1 Example 1 except that an insulator was prepared in advance and the conductor was cut at the same time as the core insulator 7 was formed by pushing the insulator.
A coil component was produced in the same manner as described above. However, in Example 1, the step of pouring and filling the ferrite slurry into the cavity on the inner surface of the outer insulator 1 and flattening to form the core insulator 7 could be omitted.

(Embodiment 3) As a method of cutting the conductor 2 at the corners of the three-dimensional spiral-shaped step portion 1b of the outer insulator 1, a rotating body having a ground surface (using a reamer having a sharp surface ) Was pressed against the corner of the step-like slope to cut the conductor 2, and a coil component was produced in the same manner as in Example 1.

(Example 4) The method of cutting the conductor 2 at the corners of the three-dimensional spiral-shaped step portion 1b of the outer insulator 1 is the same as that of Example 1 except that the conductor 2 is cut using a laser. A coil component was produced.

No defects such as peeling, cracking and warping were observed in the coil component of the present invention obtained by the above method.
In addition, there was no failure such as short circuit, and the yield was excellent. Furthermore, the electrical characteristics measured using an impedance analyzer or the like were excellent.

As described above, according to the present invention, the coil component can be manufactured with less man-hour than the conventional laminated coil component, and a coil component excellent in productivity can be obtained.

[0058]

As is apparent from the above description, the method for manufacturing a coil component according to the present invention is excellent in productivity because it is not a lamination method, and since the coil is accurately formed and defects such as short circuit do not occur. Has an excellent yield. further,
For example, since the conductor is located on the step-like slope provided in the conical hollow portion, a low-height coil component can be manufactured,
In addition, a coil component having excellent electrical characteristics can be obtained with almost no floating capacitance at the conductor turn.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a coil component according to an embodiment of the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a perspective view schematically showing another embodiment.

FIG. 4 is a sectional view of an outer insulator showing a method for manufacturing a coil component according to the present invention.

FIG. 5 is a sectional view showing a state where the conductor is formed.

FIG. 6 is a sectional view showing a state where the conductor is cut.

FIG. 7 is a sectional view of a state where the lower magnetic body is combined.

FIG. 8 is a sectional view showing a state where a concentric insulator is formed.

FIG. 9 is a sectional view of a state where the upper magnetic body is combined.

FIG. 10 is a sectional view showing a state in which the end face electrode is formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer insulator 1a Hollow part 1b Three-dimensional spiral-shaped stepped part 2 Conductor 3,4 Leader 5,6 End electrode 7 Core insulator 8 Upper magnetic body 9 Lower magnetic body

Claims (8)

[Claims] 1. A hollow inner surface of an outer insulator provided with a conical or pyramid-shaped hollow portion at the center thereof has a plurality of turns, and the diameter of each turn portion is gradually located in a different plane from one end to the other end. Forming an outer insulator having a step-shaped slope, forming a conductor on the inner surface of a hollow portion of the hollow outer insulator, and cutting the conductor at a corner of the step-shaped slope; Manufacturing method of coil parts. 2. The method according to claim 1, wherein the hardness of the outer insulator is larger than the hardness of the conductor. 3. The step of cutting the conductor at the corners of the step-like slope includes cutting the conductor by pressing a conical or pyramidal mold having substantially the same shape as the conical or pyramid-shaped hollow portion of the outer insulator. The method for manufacturing a coil component according to claim 1. 4. The step of cutting the conductor at the corner of the step-like slope is a step of cutting the conductor by pushing a core insulator having substantially the same shape as the conical or pyramid-shaped hollow portion of the outer insulator. A method for manufacturing the coil component according to claim 1. 5. The method according to claim 4, wherein the hardness of the core insulator is higher than the hardness of the conductor. 6. The method for manufacturing a coil component according to claim 4, wherein the hardness of the outer insulator is greater than the hardness of the conductor, and the hardness of the core insulator is greater than the hardness of the conductor. 7. The coil according to claim 1, wherein the step of cutting the conductor at the corner of the step-like slope is a step of pressing a rotating body having a ground surface against the corner of the step-like slope to cut the conductor. The method of manufacturing the part. 8. The method for manufacturing a coil component according to claim 1, wherein the step of cutting the conductor at the corner of the step-like slope is a step of cutting the conductor using a laser.