JPH0512975Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of the invention] The invention relates to a chip-shaped inductance element,
In particular, the present invention relates to a chip-shaped inductance element having a cylindrical shape or a rectangular parallelepiped shape.

[Prior Art and Problems] The prior art will be explained with reference to FIGS. 6 to 8 and FIG. 2 relating to the present invention.

Although it is not publicly known, Figure 6 is
60-156489 is an enlarged perspective view of a magnetic sleeve 31 according to the prior art proposed in No. 60-156489. As is clear from FIG. 6, both end surfaces 35, 3 of the magnetic sleeve 31
A hole 37 is formed approximately in the center of 5. Electrode layers 33, 3 are formed around the holes on both end surfaces 35, 35 of this magnetic sleeve and on the entire surface of both side surfaces 36, 36.
3' is continuously printed or coated. In this way, the magnetic sleeve 31 is coated with electrode layers 33, 33' on the entire surface of both side surfaces 36, 36 other than the end surfaces 35, 35 where the holes 37 are formed, and the side surfaces 36, 36 have a rectangular shape. This will be referred to as a rectangular magnetic sleeve, and the magnetic sleeve shown in FIG. 5 according to an embodiment of the present invention will be referred to as a rectangular parallelepiped magnetic sleeve 1' to distinguish it. Although FIG. 2 is an enlarged perspective view of the drum-shaped magnetic bobbin 9 according to the present invention, it is used for convenience in explaining the prior art. As is clear from FIG. 2, a coil winding 21 is wound around the drum-shaped magnetic bobbin 9. Guide grooves 19, 19 for drawing out the ends of the coil windings are formed on the sides of the end flanges 11, 11 of the drum-shaped magnetic bobbin. Furthermore, conductive films 17, 17 are printed or coated on both end surfaces 13, 13 of the end flanges 11, 11. The coil winding ends 15, 15 are pulled out through the guide grooves 19, 19, and the conductive film 1
It is bent and fixed on top of 7 and 17. Such a drum-shaped magnetic bobbin 9 is fitted into the hole 37 of the rectangular magnetic sleeve 31 shown in FIG. A manufacturing method for obtaining a desired chip-shaped inductance element will be briefly described with reference to FIGS. 7 and 8. 7th
The figure shows a drum-shaped magnetic bobbin 9 and a square magnetic sleeve 3.
A- in FIG. 6 showing the state inserted into the hole 37 of No. 1.
FIG. 3 is an enlarged cross-sectional view taken along line A'. For convenience of explanation, the upper coil winding terminal 15 will be explained below. The same applies to the lower coil winding terminal 15. A circular conductive metal plate 43 larger than the hole 37 in which the solder layer 39 is formed in advance is prepared. Before making a solder connection, apply a suitable flux to the area where the solder connection will be made. After that, the solder layer 39 is heated from above the conductive metal plate 43 with the solder layer 39 facing down.
The coil winding terminal 15, the conductive film 17, the electrode layer 33 around the hole, and the conductive metal plate 43 are melted and drawn out.
Simultaneously solder and connect them together. After completing the desired solder connections, an insulating layer 45 is applied (see FIG. 8). In the manner described above, the chip-shaped inductance element 27 is obtained.

Q value is generally used to express the characteristics of an inductance element. This Q value determines the frequency selection characteristics of a tuned circuit such as an LC parallel circuit.
It is known that the higher the Q value, the better the frequency selection characteristics. However, it has been found that the Q value of the chip-shaped inductance element 27 obtained as described above may decrease. The inventors of the present invention analyzed and examined various causes of the decrease in the Q value, and found that it was due to the following causes. (See Figures 7 and 8).

(a) Coil winding caused by flux flowing into the hole 37 from the gap 38 formed between the rectangular magnetic sleeve 31 and the drum-shaped magnetic bobbin 9 and adhering to the coil winding 21 during solder connection. Due to chemical effects on the line.

(b) Hole 37 in end faces 35, 35 of square magnetic sleeve
Electrode layers 33, 33' are printed or coated around the hole 37, and electrode layers 33, 33' are printed or applied on the inner wall of the hole 37.
3' may adhere, which increases eddy current loss.

(c) Solder layers 39, 39 and electrode layers 33, 33'
The strength of the magnetic sleeve-drum magnetic bobbin connection by chisel may be insufficient.

It has also been found that the above (a), (b), and (c) may impair characteristics other than the Q value of the chip-shaped inductance element.

On the other hand, the completed chip-shaped inductance element 2
7 is finally mounted at a predetermined position on the printed wiring board by soldering, and it is preferable to mount a plurality of chip elements on the printed wiring board at the same time in order to reduce the cost of mounting. This type of mounting method will be referred to as a multi-mount method. According to the multi-mount system, a plurality of chip elements are dropped from a suitable element feeding hopper through a tube into a template having device positioning holes in advance. The printed wiring board is coated with, for example, an ultraviolet curable resin in advance, and the printed wiring board is pressed from below, turned over, the template is removed, and the chip elements are fixed by irradiation with an ultraviolet lamp. After other electronic components such as leaded components are mounted on the printed wiring board, all chip elements and electronic components are soldered together at the same time. The multi-mount method is characterized by high productivity and therefore low mounting cost as mentioned above, but the shape of both sides 36, 36 on which the electrode layers 33, 33' are printed and applied is square. This multi-mounting method cannot be used for conventional rectangular chip-like inductance elements because positioning using a template is difficult, and as a result, mounting costs for square-shaped chip-like inductance elements become high. There was a problem with this. Even if you try to change this to a cylindrical one, the external electrode layers 33, 3
3' are on both end faces, and the drum-shaped bobbin is inserted into a through hole parallel to the drum-shaped bobbin, which is impossible.

On the other hand, it is also possible to fit a drum-shaped magnetic bobbin into a hole penetrating from the electrode layer 33 to 33', which would make it possible to use a cylindrical sleeve. However, the problem of flux intrusion and the problem of eddy current loss caused by adhesion of the electrode layers 33, 33' to the inner wall of the hole 37 are not solved.

[Purpose of the invention] Therefore, the purpose of the invention is to obtain a chip-shaped inductance element with good characteristics and constant quality in which the Q value does not decrease.

Another object of the present invention is to obtain a chip-shaped inductance element with low mounting cost.

[Outline of the invention] The outline of the invention will be explained with reference to FIGS. 1 to 5.

According to the present invention, the electrode layers 3, 3 are printed or coated on the entire end surfaces 5, 5 of the magnetic sleeve in which the through holes 7 are formed. The shape of the end faces 5, 5 is preferably circular, but may also be square as shown in FIG. According to the present invention, the solder layers 29, 29 for connecting the conductive films 17, 17 of the drum-shaped magnetic bobbin 9, the coil winding terminals 15, 15, and the electrode layers 3, 3 are formed around the end surfaces 13, 13. It is characterized in that it is formed so that the end surfaces 13, 13 and the electrode layers 3, 3 are connected via a conductive metal piece 23 except for a part. An insulating layer 25 is formed not only on the solder layer 29 but also on the magnetic sleeves 1, 1'.
The space 28 between the magnetic bobbin 9 and the drum-shaped magnetic bobbin 9 is also filled.

[Detailed Description of the Preferred Embodiment] A preferred embodiment of the present invention will be described with reference to FIGS. 1-5.

FIG. 1 is a perspective view of a cylindrical magnetic sleeve 1 according to the present invention. The cylindrical magnetic sleeve 1 is obtained by press-molding pre-sintered magnetic powder (preferably ferrite) and then sintering it. Electrode layers 3, 3 are printed or coated on the entire end surfaces 5, 5 of the cylindrical magnetic sleeve 1. The electrode layers 3, 3 are preferably made of a silver-palladium (Ag-Pd) alloy. FIG. 2 is a perspective view of the drum-shaped magnetic bobbin 9 according to the present invention. The drum-shaped magnetic bobbin 9 is obtained by pressure-molding pre-sintered magnetic powder (preferably ferrite) and then sintering it. A coil winding 21 is wound around the central cylindrical portion of the drum-shaped magnetic bobbin 9 . Two end flanges 11,1 of the drum-shaped magnetic bobbin
Conductive films 17, 17 are formed on end surfaces 13, 13 of 1. The conductive films 17, 17 are preferably made of silver-palladium alloy (Ag-Pd). Guide grooves 19, 19 for drawing out the coil winding are formed on the sides of the end flanges 11, 11 of the drum-shaped magnetic bobbin, and the coil winding ends 15, 15 pass through the guide grooves 19, 19. , is pulled out to the end surfaces 3 and 13, bent and fixed onto the conductive film 17. The diameter of the coil winding 21 is usually 0.03mm to 0.05mm.
Approximately mm is preferable. The drum-shaped magnetic bobbin 9 having such a structure is inserted into the through hole 7 of the cylindrical magnetic sleeve 1 . Hereinafter, a method for manufacturing a chip-shaped inductance element according to the present invention will be explained. In addition, for convenience of explanation, the left coil winding terminal 15 will be explained. A conductive metal plate 23 on which a solder layer 29 is formed in advance is prepared. The length of the conductive metal plate 23 is longer than the diameter of the through hole 7 of the cylindrical magnetic sleeve 1;
The width is made smaller than the diameter of the end surface 13 of the drum-shaped magnetic bobbin 9. The thickness of the solder layer on a conductive metal plate is usually
It is about 15 μm. Apply an appropriate flux to the parts where solder connections will be made. After that, the conductive metal plate 23 is heated with the solder layer 29 facing the coil winding terminal side to melt the solder layer 29, and the coil winding terminal 15, the conductive film 17, the electrode layer 3, and the conductive metal plate 23 are drawn out. Solder and connect at the same time. This solder connection is performed so as to connect the end surface 13 and the electrode layer 3, leaving a part of the periphery of the end surface 13. There is a slight gap 28 (see FIG. 4) between the cylindrical magnetic sleeve 1 and the drum-shaped magnetic bobbin 9. Therefore, flux and the like attached to the coil winding 21 can be removed through the gap 28 by using a part of the periphery of the end face 13 where no solder connection is made. Conventionally, the solder connection between the magnetic bobbin and the magnetic sleeve is usually made by cream solder joint, and according to such solder joint, there is a gap between the magnetic bobbin and the magnetic sleeve, so that the solder does not melt during solder melting. There was a problem that it was not possible to properly bridge the gap due to the effect of surface tension, but by using a conductive metal plate on which a solder layer has been formed in advance according to the present invention, it is possible to easily connect the magnetic bobbin and the magnetic sleeve. . After cleaning the coil winding 21, as shown in FIGS. 3 and 4, an insulating layer 25 is formed to cover the solder layer 29 and the end face 13. This insulating layer 25 also fills the gap 28 through a part of the periphery of the end face where no solder connection is made. The same applies to the right coil winding terminal 15.

In the manner described above, a cylindrical chip-shaped inductance element according to the present invention as shown in FIG. 4 is obtained.

Incidentally, it is also possible to use a rectangular parallelepiped chip-shaped inductance element in which the end face on which the hole is formed has a rectangular shape as shown in FIG.

[Operations and Effects of the Invention] According to the invention, the solder layer 29 that connects the conductive films 17, 17, the coil winding terminals 15, 15, the electrode layer 3, and the conductive metal plate 23 is connected to a part of the periphery of the end surface 13. is formed leaving behind. Therefore, this end surface 13
Since the coil winding 21 can be cleaned using a part of the surrounding area and the space 28, it is possible to suppress the chemical influence on the coil winding due to adhesion of flux, etc., and maintain a constant quality without lowering the Q value. A chip inductance element with good characteristics can be obtained. Further, since the insulating layer 25 also fills the gap 28 of the through hole 7, the coil winding is completely sealed. Furthermore, the insulating layer filled in between the two also ensures a strong connection between the magnetic sleeve and the magnetic bobbin, which allows the solder connection to be made when mounting the chip inductance element of the present invention on a printed wiring board. Intrusion of external solder can also be avoided.

Further, the cylindrical chip-shaped inductance element according to the present invention can be mounted on a printed wiring board by a multi-mounting method, so that the mounting cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is an enlarged perspective view of a magnetic sleeve of a cylindrical chip-shaped inductance element according to the present invention. FIG. 2 is an enlarged perspective view of a drum-shaped magnetic bobbin of a cylindrical chip-shaped inductance element according to the present invention. FIG. 3 is an enlarged perspective view of a cylindrical chip-shaped inductance element according to the present invention on which a solder layer and an insulating layer are formed. FIG. 4 is an enlarged cross-sectional view of the cylindrical chip-shaped inductance element of FIG. 3 along the longitudinal axis. FIG. 5 is an enlarged perspective view of a rectangular chip-shaped inductance element according to the present invention. FIG. 6 is an enlarged perspective view of a magnetic sleeve of a square chip-shaped inductance element according to the prior art. FIG. 7 is an enlarged sectional view showing how to solder connect a chip-shaped inductance element according to the prior art. FIG. 8 is an enlarged sectional view of a conventional square chip-shaped inductance element in which an insulating layer is formed. The names indicated by each number in the figure are listed below. Note that the same numbers indicate the same parts. 1,1'
...(cylindrical, rectangular parallelepiped) magnetic sleeve, 3,3
... Electrode layer, 5, 5 ... End surface of cylindrical magnetic sleeve, 7 ... Hole, 9 ... Drum-shaped magnetic bobbin, 1
1, 11... End flange of drum-shaped magnetic bobbin, 13, 13... End surface of drum-shaped magnetic bobbin,
15, 15... Coil winding terminal, 17, 17...
Conductive film, 19, 19... Guide groove, 21... Coil winding, 23, 23... Conductive metal plate, 25, 25
...Insulating layer, 27...Inductance element, 28
... Between, 29, 29... Solder layer, 31... Square magnetic sleeve, 33, 33'... Electrode layer, 35,
35... End face of square magnetic sleeve, 36, 36...
...Side surface of square magnetic sleeve, 37... Hole, 38...
...= Between, 39, 39... Solder layer, 43, 43...
...Conductive metal plate, 45, 45...Insulating layer.

Claims (1)

[Claims for Utility Model Registration] (1) A magnetic sleeve comprising a through hole extending between two end faces and an electrode layer formed almost entirely on this end face; A chip-shaped inductance element comprising a drum-shaped magnetic bobbin having two end flanges having a diameter slightly smaller than the diameter of the drum-shaped magnetic bobbin, and a central cylindrical part around which a coil winding is wound. A solder layer connecting the end of the coil winding to the electrode layer while leaving a part of the periphery of the end face of the end flange, a conductive metal piece continuous with the solder layer, the end face of the drum-shaped magnetic bobbin, and the solder. What is claimed is: 1. A chip-shaped inductance element comprising: a layer and an insulating layer covering the conductive metal piece and filling the space between the conductive metal pieces. (2) The chip-shaped inductance element according to claim 1, wherein the end surface of the magnetic sleeve is substantially circular. (3) The chip-shaped inductance element according to claim 1, wherein the end surface of the magnetic sleeve has a substantially square shape.