JPH0590076A - Manufacture of trimmer capacitor - Google Patents

Abstract

PURPOSE:To provide a manufacturing method for trimmer capacitors which prevents a stator electrode from sinking in manufacturing a stator substrate. CONSTITUTION:In manufacturing a trimmer capacitor with a dielectric rotor 2 and in turn an adjusting pin 3 superposed on a stator substrate 1, which has a stator electrode 12, located on the surface thereof, and a stator terminal 13 integrally molded, the trimmer capacitor is resin molded with the stator electrode 12 and the stator terminal 13 supported by the stator substrate 1 on the rear face of the stator electrode 12.

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 trimmer capacitor, and more particularly to a method for manufacturing a stator substrate which constitutes the trimmer capacitor.

[0002]

2. Description of the Related Art Conventionally, a trimmer capacitor is composed of a stator substrate 101, a dielectric rotor 102 and an adjusting pin 103 as shown in FIG. Stator board 10
1 is made of an insulating resin, a semi-circular stator electrode 112 is formed on the surface thereof, a stator terminal 113 integrated with the stator electrode 112 is formed at the end, and an adjusting pin 103 is further provided at the center of the surface. Through hole 111 that can penetrate
Had been formed. The dielectric rotor 102 is composed of a dielectric ceramic such as barium titanate, and a through hole 121 through which the adjustment pin 103 can pass is formed in the central portion. Further, the rotor electrode 123 is formed inside the rotor 102, one end of the rotor electrode 123 is led out to the through hole 122, and the conductive film 121 is formed on the inner wall of the through hole 122. The adjusting pin 103 is made of a metal material or the like, and the head 132 having the adjusting groove 131 formed therein and the through holes 111 and 121 are inserted through the adjusting pin 103 to rotatably hold the rotor 102 on the back surface of the stator substrate 101. Part 133
And a pin portion 134 formed with. The dielectric rotor 102 is placed on the stator substrate 101, and the adjusting pins 103 are arranged from above the dielectric rotor 102 so as to pass through the through holes 122 of the dielectric rotor 102 and the through holes 111 of the stator substrate 101. The rotor terminal 124 was fitted on the rear surface of the above and was caulked by the caulking portion 133.

As a result, a capacity corresponding to the facing area of the stator electrode 112 and the rotor electrode 123 of the dielectric rotor 102 is derived from between the stator terminal 113 and the rotor terminal 124.

To form a conventional stator substrate, as shown in FIG. 4, a stator electrode 112 and a stator terminal 11 are formed.
3 and the lead body 142 integrated with the stator substrate 10
The stator electrode 11 is placed in a mold 140, 141 having a predetermined shape corresponding to the shape of No. 1, and the mold 140, 141 is filled with resin and cured (resin molding method).
2 and stator terminal 113 embedded stator board 1
Had formed 01.

[0005]

However, when the above-mentioned stator substrate 101 is formed by a resin molding method, it is extremely difficult to hold the stator electrode 112 on the surface of the stator substrate 101 before the resin is cured.
For example, as shown in FIG. 4, molds 140 and 141, for example.
When the lead body 142 is clamped, the stator electrode 112 is displaced due to its own weight, and the stator electrode 112 is completed and a part of the stator electrode 112 is embedded in the substrate. There was a high possibility that the stator electrode would sink. When this sinking of the stator electrode occurs, the resin forming the stator substrate 101 is covered on the stator electrode 112, and when assembled into a trimmer capacitor, the dielectric rotor 102 and this resin are formed between the stator electrode 112 and the rotor electrode 123. As a result, a sufficient dielectric constant cannot be obtained, and the value falls outside the adjustable range of the predetermined trimmer capacitor. Therefore, generally, the resin component and the curing conditions are finely set in consideration of the shape of the mold, the thickness and size of the stator electrode to solve the sinking of the stator electrode. There was a problem that it required various process controls.

An object of the present invention is to provide a method of manufacturing a trimmer capacitor which can suppress the above-mentioned sinking of the stator electrode and can obtain a stable adjustable range.

[0007]

The present invention is a trimmer capacitor in which a dielectric rotor having a rotor electrode and an adjusting pin are superposed on a resin stator substrate having a stator electrode arranged on the surface thereof. The resin-made stator substrate is formed by resin molding so that the front surface of the stator electrode is exposed using a mold having a protrusion that supports the back surface of the stator electrode.

[0008]

According to the present invention, when the stator substrate is formed on the resin mold, the stator electrode portion of the integrated lead portion of the stator electrode and the stator terminal is supported from the back surface side. With this, the surface of the stator electrode and the surface of the stator substrate can be reliably and easily made to be the same surface after the resin is hardened in the stator electrode. By using this, the stator electrode and the dielectric rotor are not separated. The contact state is stable, and a trimmer capacitor having a predetermined adjustable range can be easily obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional structural view of a trimmer capacitor according to the present invention.

The trimmer capacitor includes a stator substrate 1,
It is composed of a dielectric rotor 2 and an adjusting pin 3.

The stator substrate 1 is made of an insulating resin, a through hole 11 is formed in the central portion, and a semicircular stator electrode 12 is arranged on the surface so as to surround the through hole 11. A stator terminal 13 is formed at one end. The stator electrode 12 and the stator terminal 13 are integrally formed. A rotor terminal 24 is formed on the other end of the stator substrate 1.

The dielectric rotor 2 is made of a dielectric ceramic such as barium titanate and has a conductor film 2 on its inner wall in the center thereof.
The through hole 22 having the number 1 is formed. Further, a semicircular rotor electrode 23 is formed inside thereof.

The adjusting pin 3 is made of a metal material and comprises a head portion 32 having an adjusting groove 31 and a pin portion 34 having a crimp portion 33 at one end.

To assemble the trimmer capacitor, first, the dielectric rotor 2 is placed on the stator substrate 1, and then the pin portion 34 of the adjusting pin 3 is inserted into the through holes 11 and 22 of the stator substrate 1 and the dielectric rotor 2. Then, the back surface of the stator substrate 1 is caulked by the caulking portion 33 through a part of the rotor terminal 24. The dielectric rotor 2 and the adjusting pin 3 are fixed to the through hole 22 having the conductor film 21 on the inner wall.
A conductive adhesive or the like is interposed when the pin portion 34 is inserted through. That is, the rotor electrode 23 is electrically connected to the rotor terminal 23 via the conductive adhesive of the conductor film 21 and the pin portion 34.

As a result, the capacitance determined according to the facing area of the stator electrode 12 and the rotor electrode 23 is led out between the stator terminal 13 and the rotor terminal 24.

The stator substrate 1 used for such a trimmer capacitor is formed by a resin molding method as shown in FIG.

First, resin molds 40 and 41 are prepared. By combining the molds 40 and 41, a space 42 having a predetermined shape is formed according to the outer shape of the stator substrate.

The mold 40 has a conical or pyramidal projection 4 for holding the stator electrode rear surface A portion of the stator metal fitting 43 in which the stator electrode and the stator terminal are integrated from the bottom surface.
4 are formed. The height of the protruding portion 44 is the mold 40,
The height is such that a gap corresponding to the thickness of the stator metal fitting 43 is generated with respect to the space 42 formed when 41 are combined.

Specifically, the metal mold 40 has a stator metal fitting 43.
To place. At this time, the protrusion 4 is formed on the back surface A of the stator electrode.
4 are brought into contact with each other to hold the stator fitting 43 securely. Next, the mold 41 is combined with the mold 40 to form a space 42 corresponding to the outer shape of the stator substrate. This allows
The surface side of the stator electrode comes into complete contact with the upper surface of the inner wall of the mold 41. That is, the metal mold 40 and the metal mold 41 are combined with each other, a part of the stator metal fitting 43 is extended between them, and the stator electrode 12 of the stator metal fitting 43 is further extended.
The side is sandwiched between the protrusion 44 and the upper surface of the inner wall of the mold 41.

Next, a liquid resin insulating resin such as polyester is injected into the space 42 from the resin injection hole 45 formed in the mold 40 or a part of the mold 41. After that, the resin is cured, the mold 40 and the mold 41 are separated from each other, and the stator substrate 1 integrated with the stator fitting 43 is produced.

Since the stator substrate 1 is formed by the above-mentioned molding, there is no sinking of the stator electrode during the curing of the resin, and the surface of the stator substrate 1 and the surface of the stator electrode 12 are completely in the same plane. Therefore, when assembled into a trimmer capacitor, the stator electrode 12 and the dielectric rotor 2 are surely brought into contact with each other, so that the desired capacity and capacity adjustment range can be stably obtained.

Further, on the stator substrate 1 thus formed, the traces (pinholes) 15 of the protrusions 44 extending from the back surface side to the back surface of the stator electrode 12 are formed, but in terms of characteristics. This does not cause any trouble, and since cream solder or the like is used when the printed circuit board is mounted, the solder does not penetrate to the back surface of the stator electrode 12 through the pinholes 15, so there is no problem.

According to the above-mentioned embodiment, the shape of the protrusion 44 is described as a conical shape or a pyramidal shape, but any shape may be used so that the molds 40 and 41 can be easily separated from the hardened stator substrate. Is not limited to a conical shape or a pyramidal shape, but can be changed to various shapes.

[0024]

As described above, according to the manufacturing method of the present invention, since the stator substrate can be formed with the stator electrode held from the back side, it is possible to easily prevent the sinking of the stator electrode. By making the surface of the stator substrate and the surface of the stator electrode the same, it is possible to easily obtain a trimmer capacitor having stable capacitance characteristics.

[Brief description of drawings]

FIG. 1 is a sectional structural view of a trimmer capacitor according to the present invention.

FIG. 2 is a cross-sectional view illustrating molding of a stator substrate.

FIG. 3 is a cross-sectional structure diagram of a conventional trimmer capacitor.

FIG. 4 is a cross-sectional view illustrating molding of a conventional stator substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Stator substrate 11 ... Through hole 12 ... Stator electrode 13 ... Stator terminal 2 ... Dielectric rotor 22 ... Through hole 23 ... Rotor electrode 24 ... Rotor terminal 3 ...・ ・ ・ Adjusting pin 31 ・ ・ ・ Adjusting groove 32 ・ ・ ・ Head 33 ・ ・ ・ Crimping part 34 ・ ・ ・ Pin part

Claims (1)

[Claims] 1. A trimmer capacitor in which a dielectric rotor having a rotor electrode and an adjusting pin are superposed on a resin-made stator substrate having a stator electrode arranged on the surface thereof, wherein the resin-made stator substrate is a stator electrode. A method for producing a trimmer capacitor, characterized in that a mold having a protrusion supporting the back surface of the stator is used to perform resin molding so that the surface of the stator electrode is exposed.