JPS5953686B2 - Stacked intermediate frequency transformer and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intermediate frequency transformer, and more particularly to a stacked intermediate frequency transformer and a method for manufacturing the same.

Conventionally, an intermediate frequency transformer consists of a transformer section consisting of a magnetic core having a pair of windings, an adjustable magnetic core positioned to change the inductance of the magnetic core, and a capacitor section combined with the transformer section. It is completed. The manufacturing process is complicated, as the transformer section and capacitor section are manufactured using completely different processes, and the connection between them requires lead wires and soldering. In addition, the product has disadvantages such as being large in size and being susceptible to mechanical shock. The present inventor has recently proposed an inductor or transformer using a multilayer method.

This method is compact, mechanically strong, and
A laminated transformer etc. having advantages such as automation of work such as soldering can be obtained. The present invention applies this technology to an intermediate frequency transformer. Briefly, in the present invention, a laminated transformer part and a laminated capacitor part are made by a lamination method, holes are provided in the insulator part of the laminated transformer part,
These two laminated transformer parts and the laminated capacitor part are overlapped and combined, and fired at high temperature to form a sintered body that integrates the whole body.The outer peripheral surface of the sintered body is covered with an external terminal, and the hole part is covered with a sintered body. A multilayer intermediate frequency transformer is provided by inserting or screwing together an adjusting magnetic core.

Since the transformer of the present invention has a monolithic structure in which the whole is integrated, it is mechanically strong and the whole is miniaturized.
The shape can also be standardized, and benefits such as being suitable for automatic soldering etc. can be obtained.

Also, from a manufacturing perspective, the transformer section and capacitor section can be formed in advance and then superimposed on each other, so even if each section is constructed from a few standard products, the desired characteristics can be obtained from a wide range of characteristics by combining them. You can choose. In addition, since all processes can be manufactured using the lamination method, mass production and process stability can be achieved. The present invention will be described in detail below with reference to the drawings.

In the following examples, the magnetic layer is formed by making a paste of insulating magnetic ferrite powder with a binder and spreading it into a sheet or printing it. Each magnetic layer may be constructed as multiple small sections of large-area magnetic sheets, and after lamination, each unit may be cut along the contour of the element, or it may be formed separately as multiple printed layers from the beginning. Good too. The following discussion refers to a single component, but this should be considered for convenience of explanation. Further, in the following examples, the dielectric layer is formed by forming dielectric powder (BaTiO3, TiO2, etc.) into a paste using a binder, and then rolling this into a sheet or printing it. The conductor pattern and the electrode layer are made by printing a powder of a conductive metal (for example, a heat-resistant metal such as Pd or Ag-Pd) in the form of a paste paint. In the following, we will only refer to printing methods, but we do not intend to exclude examples of spreading onto sheets. Now, FIGS. 1 to 6 show the manufacturing process of the laminated transformer section.

As shown in FIG. 1, first, a magnetic layer 1 is formed by printing. Next, a coil-forming conductor 2 is formed near the right side of the magnetic layer 1 by printing, and at this time, one end of the conductor 2 is exposed on the upper side of the magnetic layer 1 to form a lead-out portion a. Next, as shown in FIG. 2, a magnetic layer 3 is printed on the upper part of the conductor 2, leaving one end of the conductor 2, and then a conductor 4 connected to the conductor 2 is printed in a hook shape. Moving on to the process shown in Fig. 3, a magnetic layer 5 is printed on the lower part of the laminate, leaving one end of the conductor 4, and then a conductor 6 connected to the conductor 4 is printed in a hook shape. 6 to form a pull-out part b extending over the side of the laminate. Furthermore, as shown in FIG. 4, after printing the magnetic layer 7, a conductor 8 is printed in a hook shape so as to be connected to the conductor 6, and at this time, one end of the conductor 8 is pulled out to the upper side of the laminate to form a lead-out part. Let it be C. Note that in the above steps, the number of laminated layers and the number of turns of the coil-forming conductor can be adjusted as desired. After the process shown in FIG. 4 is completed, a second coil forming pattern is formed, which has a second coil forming pattern starting from the upper drawer part d and ending at the drawer part e, on which a magnetic material (not shown) similar to that of the magnetic layer 1 is printed. The laminate is printed in the same manner as in FIGS. 1 to 4 (not shown), and finally the magnetic layer 9 is printed as shown in FIG. After the lamination is completed, a hole 10 is punched through the center of the two coil patterns formed by the conductors 2, 4, 6, 8, etc., as shown in FIG. 7 to 10 show the manufacturing process of the capacitor part.

As shown in FIG. 7, first a dielectric layer 11 is printed, and then an electrode layer 12 is printed thereon. At this time, one end of the electrode 12 is made to have a lead-out portion g exposed on the lower right side of the dielectric layer 11. After printing the dielectric layer 13 on the entire surface as shown in FIG. 8, the electrode layer 14 facing the electrode layer 12 is formed by printing as shown in FIG. Let it be f. After repeating the above steps a necessary number of times, the dielectric layer 15 is finally printed as shown in FIG. FIG. 11 shows a laminated transformer part A made according to the steps shown in FIGS. 1 to 6;
This shows a step of superimposing a laminated capacitor part B produced according to the steps shown in FIGS. C in the figure is a layer with properties intermediate between a magnetic material and a dielectric material, and is a layer for preventing cracks due to sintering shrinkage, etc. (for example, a layer made from a paste of a mixture of magnetic powder and dielectric powder). . Layer C can be omitted in some cases. As shown in FIG. 11, the laminates A, B and layer C are stacked one on top of the other and compressed (tightened) by applying pressure from above and below to integrate the whole.

Next, this stacked body is placed in a firing furnace and fired at a predetermined temperature to obtain a laminate that is integrated as a whole. The thus obtained laminate has conductor lead-out portions A, b, c, d as shown in Fig. 12.
, e, f, and g are exposed on the side, so the 13th
As shown in the figure, a conductive paste containing silver or copper is coated and baked to form external terminals 16, 17, 18, 19, and 20.

By screwing the threaded magnetic core 21 into the hole 10, the intermediate frequency transformer of the present invention is completed. In this example, the hole 10 is a screw hole, but it may be tapped into a screw hole after the compression process shown in FIG. 11, for example. Alternatively, instead of using hole 10 as a screw hole, a plastic or metal plate or cover is glued or fixed to the laminated intermediate frequency transformer, and a screw hole is formed in the plastic plate to hold the screw of the adjusting magnetic core. You may let them. The equivalent circuit of the intermediate frequency transformer of the above embodiment is as shown in FIG. Next, another example of the present invention will be described.

In the examples shown in Figures 1 to 15, the laminated transformer part A and the laminated capacitor part B were integrated and then fired, but the process was changed and the laminated transformer part A and the laminated capacitor part B were fired separately, and then they were fired together. A structure similar to that shown in FIG. 12 may be obtained by bonding. Finally, attach the external terminals as shown in Figure 13.
As described above, according to the present invention, there is no need for a connection lead between L and C, the process becomes more consistent, the product becomes more integrated and smaller, and soldering (direct attachment) using external terminals becomes possible. Become.

[Brief explanation of the drawing]

1 to 6 are plan views showing the manufacturing process of the transformer section of the intermediate frequency transformer of the present invention, FIGS. 7 to 10 are plan views showing the manufacturing process of the capacitor section, and FIG. FIG.
FIG. 2 is a perspective view showing the combined laminate, FIG. 13 is a perspective view of the completed multilayer intermediate frequency transformer, FIG. 14 is a sectional view thereof, and FIG. 15 is an equivalent circuit diagram. The main parts in the figure are as follows. 1, 3, 5, 7, 9:
Magnetic layer, 2, 4, 6, 8: Coil forming conductor, 10:
Holes, 11, 13, ] 5: Dielectric layer, ] 2, 14: Electrode layer, 16, 17, 18, 19, 20: External terminals.

Claims (1)

[Scope of Claims] 1. A plurality of insulating magnetic layers and at least two sets of conductor pieces for forming a plurality of coils of approximately half a turn are connected to the ends of the conductor pieces through the edges of the magnetic layers. An intermediate frequency transformer in which a laminated body for a transformer is alternately laminated so as to be connected to each other, and a laminated capacitor in which a plurality of dielectric layers and a plurality of electrode layers are alternately laminated are superimposed and sintered, wherein the magnetic layer A multilayer intermediate frequency transformer characterized by having a hole in which an adjustable magnetic core is inserted. 2. A plurality of unfired insulating magnetic layers and at least two sets of a plurality of coil-forming conductor pieces for approximately half a turn are placed through the edges of the magnetic layers so that the ends of the conductor pieces overlap. A laminate for a transformer is made by alternately laminating a plurality of unfired dielectric layers and a plurality of conductor layers for electrodes, a laminate for a capacitor is made by alternately laminating a plurality of unfired dielectric layers and a plurality of conductor layers for electrodes, and the laminate for a transformer is A method for manufacturing a multilayer intermediate frequency transformer, comprising forming a hole in the magnetic layer, superimposing and combining both of these laminates, firing, and inserting an adjustable magnetic core into the hole.