JPH1187172A - Electrostatic capacitance adjusting driver for variable capacitor and adjustment of electrostatic capacitance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow correct electrostatic capacitance adjustment to be made easily by suppressing variations in floating capacitance caused in relation to a driver groove between the inserted state and the non-inserted state of a driver in a variable capacitor, in which the driver groove for allowing the driver to be inserted to rotate a rotor for making an electrostatic capacitance adjustment is provided, so as to pass through the rotor and in which the driver comes in contact with a stator when inserted into the driver groove. SOLUTION: A distal end surface 23 of a bit 22 of a electrostatic capacitance adjusting driver 21 is formed into, e.g. a quadrangular pyramid so that the center of the surface 23 projects from the peripheral thereof. It is so arranged that the bit 22 comes in contact with a stator 2 only at a limited portion of the surface 23, when the bit 22 is inserted into a driver groove 13. As a result, an air layer between the surface 23 and the stator 2 is provided reliably, and thus floating capacitance variations can be reduced between the inserted state and the non-inserted state of the bit 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driver for adjusting the capacitance of a variable capacitor and a method for adjusting the capacitance using the driver. The present invention relates to an improvement for making it easier to perform.

[0002]

2. Description of the Related Art A variable capacitor of interest to the present invention is not known yet, but has been filed by the present applicant in Japanese Patent Application No. Hei.
No. 126586 is described in "Variable Capacitor" filed on May 16, 1997. FIG.
The variable capacitor 1 proposed in the prior application is shown.

Referring to FIG. 6, variable capacitor 1 has a stator 2, a rotor 3 and a cover 4.
Is provided. The main part of the stator 2 is made of a dielectric material such as ceramic. The rotor 3 is made of a metal such as brass. The cover 4 is made of a metal such as stainless steel or a copper alloy. Hereinafter, a detailed structure of each element described above will be described.

[0004] The stator 2 has a symmetrical structure as a whole. Inside the stator 2, stator electrodes 5 and 6 are formed side by side. Stator terminals 7 and 8 are formed on the outer surfaces of the ends of the stator 2 with conductive films so as to be electrically connected to the stator electrodes 5 and 6, respectively. The stator 2 has a part of the dielectric material constituting the stator 2 and the stator electrodes 5 and 6.
Is formed on the dielectric layer 9.

As described above, the two stator electrodes 5 and 6 and the two stator terminals 7 and 8 are formed because the structure of the stator 2 is symmetrical and the variable capacitor 1 using the stator 2 is formed. This is because it is not necessary to consider the direction of the stator 2 in assembling. The rotor 3 is disposed on the upper surface of the stator 2 so as to be in contact with the above-described stator 2, and has a substantially lower surface facing the stator electrodes 5 and 6 via the dielectric layer 9. The semicircular rotor electrode 10 is formed with a projecting step. Further, on the lower surface side of the rotor 3 and in a region other than the region where the rotor electrode 10 is formed, a convex portion 11 having a height equal to the height of the step portion for the rotor electrode 10 is formed. The presence of the electrode 10 prevents the rotor 3 from tilting.

A driver groove 13 is provided in the rotor 3 to receive a capacitance adjusting driver 12 for rotating the rotor 3 and thereby adjusting the capacitance of the variable capacitor 1.
Are formed. The driver groove 13 is formed with a through hole, and has, for example, a square cross section in order to make the rotor 3 thinner which leads to a thinner variable capacitor 1.

[0007] The cover 4 is fixed to the stator 2 while accommodating the rotor 3.
The rotor 3 is held rotatably with respect to the stator 2. The cover 4 has an adjustment hole 14 for exposing the driver groove 13 of the rotor 3, thereby allowing the driver 12 to be inserted into the driver groove 13. Around the adjustment hole 14, there is provided a spring action portion 15 which partially contacts the upper surface of the rotor 3 and exerts a spring action for pressing the rotor 3 toward the stator 2. The spring action portion 15 is provided by the metal material itself around the adjustment hole 14 by being shaped to be inclined downward toward the center around the adjustment hole 14.

A plurality of protrusions 16 (only one protrusion 16 is shown) substantially in point contact with the rotor 3 are distributed on the spring action portion 15 at regular intervals along the rotation direction of the rotor 3. It is provided to be. These projections 16
For example, it can be formed by molding a metal plate constituting the cover 4. By providing the projection 16 on the spring action portion 15, the place where the spring action portion 15 presses the rotor 3 is definitely determined, so that the parallelism on both surfaces of the rotor 3 is inferior, the flatness of the rotor 3 and the spring action portion 1
Even if the flatness of the tip of 5 is inferior, the spring action portion 15 can apply a stable contact pressure to the rotor 3.

The cover 4 is provided with a rotor terminal 17 extending downward. The stator 2 as described above,
The variable capacitor 1 is assembled using the rotor 3 and the cover 4 as follows. A rotor 3 is arranged on the stator 2, and a cover 4 is arranged so as to cover the rotor 3. Next, the cover 4 is fixed to the stator 2 while pressing the cover 4 toward the stator 2 so that the rotor 3 is pressed against the stator 2.

At this time, the rotor terminal 17 provided on the cover 4 is provided at a position opposed to the stator terminal 8 provided on the stator 2. There is no problem electrically because it does not function as. In such an assembled state, the rotor electrode 10 is
They face each other with the dielectric layer 9 interposed therebetween to form a capacitance.
This capacitance depends on the stator terminal 7 electrically connected to the stator electrode 5 and the rotor 3 forming the rotor electrode 10.
And is taken out by the rotor terminal 17 provided on the cover 4 which comes in contact with the cover 4.

In order to change the effective area of the rotor electrode 10 facing the stator electrode 5 in order to adjust the capacitance, the rotor 3 is rotated. Therefore, the bit portion 18 of the driver 12 is inserted into the driver groove 13 provided in the rotor 3, and by rotating the driver 12 in this state, the rotor 3 is rotated. The bit portion 18 may have any shape as long as it can apply a rotational force to the rotor 3. However, in the illustrated variable capacitor 1, the driver groove 13 has a square cross-section, and thus is typically formed. Has a square prism shape.

[0012]

The bit portion 18 of the above-described capacitance adjusting driver 12 is preferably non-electromagnetic inductive and non-conductive.
In general, an insulator is used, and zirconia is advantageously used particularly from the viewpoint of abrasion resistance. On the other hand,
In the variable capacitor 1 having the above-described structure, not only the original capacitance due to the opposition between the stator electrode 5 and the rotor electrode 10, but also, for example, the opposition between the stator electrode 5 and a portion of the rotor 3 other than the rotor electrode 10 or the stator electrode 5
A small floating capacitance is inevitably formed due to the opposition of the cover 4 and the like.

Although such stray capacitance does not itself adversely affect the quality of the variable capacitor 1, when the bit portion 18 of the driver 12 is inserted into the driver groove 13, as described above, Since the bit 13 is formed with a through hole, the bit 18 comes into surface contact with the stator 2 and most of the air in the driver groove 13 is replaced by the material forming the bit 18.
It changes more or less.

Therefore, such a change in the stray capacitance actually occurs before and after the driver 12 is inserted into the driver groove 13 for adjusting the capacitance, and when the driver 12 is inserted into the driver groove 13. Between the time when the driver 12 is pulled out of the driver groove 13 after the adjustment is completed,
Can happen. As a result, a change in the stray capacitance causes a change in the capacitance obtained in the entire variable capacitor 1, and it is difficult to accurately adjust the capacitance. In particular, as described above, when the bit portion 18 is in surface contact with the stator 2 and the bit portion 18 is made of zirconia,
Since the relative dielectric constant of zirconia is relatively large at about 20,
The change in the stray capacitance between the state of being inserted into the driver groove 13 and the state of not being inserted into the driver groove 13 is relatively large, and this change in the stray capacitance cannot be ignored for accurate adjustment of the capacitance.

An object of the present invention is to provide a driver for adjusting the capacitance of a variable capacitor and a method of adjusting the capacitance, which can reduce the above-mentioned change in the stray capacitance.

[0016]

A variable capacitance driver to which a capacitance adjusting driver and a capacitance adjusting method according to the present invention are applied is disposed so as to be in contact with the stator, forming a stator electrode. Thing,
A rotor electrode facing the stator electrode via a dielectric is formed, and the rotor electrode is held rotatably with respect to the stator to adjust the capacitance by changing the effective facing area of the rotor electrode with respect to the stator electrode. And a rotor groove provided with a through hole for a rotation operation by a capacitance adjusting driver.

The capacitance adjusting driver according to the present invention is used to rotate the rotor by inserting the variable capacitor into the driver groove to adjust the capacitance. The tip portion of the bit portion inserted into the driver groove is provided with a shape in which the center portion protrudes from the peripheral portion.

There are various embodiments regarding the above-mentioned bit portion and tip surface. For example, the bit portion has a quadrangular prism shape, the tip surface forms a quadrangular pyramid, the embodiment, the tip surface forms a spherical surface, the embodiment, and the tip surface has a shape in which a projection is formed at the center of a flat surface. , An embodiment, an embodiment, and the like, in which a bit portion has a minus cross-sectional shape and is defined by two surfaces that intersect so that a front end surface protrudes in a V-shape.

When the bit portion is made of a material having dielectric properties, the present invention operates more advantageously. Further, the capacitance adjusting method according to the present invention is a method for adjusting the capacitance of the variable capacitor described above, and is used to rotate the rotor by inserting it into the driver groove. Thus, a driver for capacitance adjustment is prepared, in which the center of the bit portion to be inserted into the driver groove has a shape projecting from the peripheral portion, and the bit portion of the driver is inserted into the driver groove. The method is characterized in that the method includes the steps of rotating the rotor by rotating the driver while inserting.

In this capacitance adjusting method, the stator includes a dielectric layer formed so as to cover the stator electrode, the above-described dielectric is provided by the dielectric layer, and the rotor is made of a conductive material. And the rotor electrode is
It is advantageously applied to adjust the capacitance of such a variable capacitor, which is formed with a step which protrudes on the side in contact with the stator.

[0021]

FIG. 1 is a diagram corresponding to FIG. 6 for explaining a first embodiment of the present invention. FIG. 1 shows a variable capacitor 1 substantially similar to that shown in FIG. About this variable capacitor 1,
The description given with reference to FIG. 6 will be omitted by using the description above.

In order to adjust the capacitance of the variable capacitor 1, a capacitance adjusting driver 21 is prepared. The driver 21 has a bit portion 22 inserted into the driver groove 13 of the rotor 3. FIG. 2 is a perspective view showing the bit portion 22 of the driver 21 from the front end surface thereof.
The bit portion 22 may have any shape as long as the bit portion 22 can engage with the driver groove 13 and apply a rotational force to the rotor 3. However, in the illustrated variable capacitor 1, as described above, Since the driver groove 13 has a square cross section, the driver groove 13 typically has a quadrangular prism shape, more specifically, a regular square prism shape.

The bit portion 22 is preferably non-electromagnetic inductive and non-conductive.
In general, an insulator is used for 2 and zirconia is advantageously used particularly from the viewpoint of abrasion resistance. The tip surface 23 of the bit portion 22 is provided with a shape such that the center portion protrudes from the peripheral portion. In this embodiment, as shown in FIG. 2, the distal end surface 23 forms a quadrangular pyramid.

As shown in FIG. 1, the bit portion 22 provided in the driver 21 is inserted into the driver groove 13 of the rotor 3 through the adjustment hole 14 of the cover 4, and the driver 21 is rotated in this state. As a result, the rotor 3 is rotated, whereby the effective facing area of the rotor electrode 10 with respect to the stator electrode 5 is changed to adjust the capacitance.

At this time, since the front end surface 23 forms a quadrangular pyramid, it only contacts the stator 2 at its apex only, and a sufficient air layer is secured between the front end surface 23 and the stator 2. . Therefore, even when the bit portion 22 is made of a dielectric material such as zirconia, for example, the stator electrode 5 faces the rotor 3 other than the rotor electrode 10 or the stator electrode 5 and the cover 4 The stray capacitance due to the opposition of the driver 21 before and after the driver 21 is inserted into the driver groove 13, and when the driver 21 is inserted into the driver groove 13 and when the driver 21 is removed from the driver groove 13 after the adjustment is completed. Can hardly be changed. As a result, accurate adjustment of the capacitance can be performed more easily.

In the first embodiment described above, the tip surface 23 of the bit portion 22 of the capacitance adjusting driver 21 is used.
However, although a quadrangular pyramid is formed, the form of such a bit portion or its tip end surface can be variously changed as shown and described below with respect to a typical one. FIG. 3 to FIG. 5 are views corresponding to FIG. 2 showing the capacitance adjusting drivers according to the second to fourth embodiments of the present invention, respectively.

The capacitance adjusting driver 31 shown in FIG.
The tip surface 33 of the bit portion 32 forms a spherical surface.
Bit portion 4 of capacitance adjusting driver 41 shown in FIG.
The second end surface 43 has a shape in which a projection 44 is formed at the center of the flat surface. The protrusion 44 is, in the illustrated embodiment,
Although it has a hemispherical shape, the shape may be changed to a cone, a pyramid, a thin column, or the like.

The capacitance adjusting driver 51 shown in FIG.
The bit portion 52 has a minus cross-sectional shape, and the tip surface 53 is defined by two surfaces that intersect so as to project in a V-shape. As described above, any of the drivers 31, 41, and 51 according to the second to fourth embodiments comes into contact with the stator 2 only in a limited region of the distal end surfaces 33, 43, and 53, and therefore, the distal end surface A sufficient air layer can be ensured between 33, 43 and 53 and the stator 2.

The variable capacitor to which the present invention can be applied is not limited to the illustrated variable capacitor 1. For example, in the illustrated variable capacitor 1, the cover 4 is made of metal and the rotor 3 is made of metal, so that a conductive path for extracting the rotor electrode 10 is formed by the rotor 3 itself and the cover 4 itself. Although the rotor terminal 17 is provided on the cover 4, the present invention is not limited to such a configuration.

More specifically, the rotor is not made of metal as a whole, but is made of, for example, an electrical insulator such as alumina and has conductors formed in necessary portions including the rotor electrode portion. May be replaced by
Further, the dielectric material interposed between the rotor electrode and the stator electrode may be formed on the rotor side. Also, the cover may be replaced with a cover made of an electrical insulator such as a resin and formed with a conductor at a necessary portion, instead of being made of a metal as a whole. In addition, if a conductive path for extracting the rotor electrode is formed in a portion other than the rotor or in a portion other than the cover, the rotor or the cover needs to be made of a metal as a whole, and a part of the metal needs to be made of a metal Nor.

Further, the present invention can be applied to a variable capacitor without a cover as long as the rotor is held rotatably without using a cover.

[0032]

As described above, according to the capacitance adjusting driver of the present invention, the tip end face of the bit portion inserted into the driver groove is provided with a shape in which the center portion protrudes from the peripheral portion. As a result, only a limited area of the front end surface is brought into contact with the stator, so that a sufficient air layer is secured between the front end surface and the stator. Therefore, the stray capacitance formed in connection with the driver groove is changed before and after the driver is inserted into the driver groove, and when the driver is inserted into the driver groove and when the driver is removed from the driver groove after the adjustment. Can hardly be changed. as a result,
Accurate adjustment of the capacitance can be performed more easily.

If the characteristic portion according to the present invention is not adopted and the bit portion of the capacitance adjusting driver is made of a material having a dielectric property such as zirconia, when the bit portion is inserted into the driver groove as described above, And the stray capacitance will change more between
The capacitance adjusting driver according to the present invention exhibits a particularly remarkable effect when the bit portion is made of a dielectric material.

According to the capacitance adjusting method according to the present invention, as a capacitance adjusting driver to be inserted into the driver groove and rotate the rotor, the center of the bit portion at the tip end surface is formed. Since a bit having a shape protruding from the peripheral portion is used, when the bit portion is inserted into the driver groove, the bit portion comes into contact with the stator only in a limited area of the front end surface. A sufficient air space is secured between the two. Therefore, the stray capacitance formed in connection with the driver groove is changed before and after the driver is inserted into the driver groove, and when the driver is inserted into the driver groove and when the driver is removed from the driver groove after the adjustment. Can hardly be changed. As a result, accurate adjustment of the capacitance can be performed more easily.

The stator includes a dielectric layer formed to cover the stator electrodes, wherein the aforementioned dielectric is provided by the dielectric layer, the rotor is made of a conductive material, and the rotor electrode is Such a variable capacitor, which is formed with a projecting step on the surface side in contact with the stator, is liable to cause a change in stray capacitance between each state of insertion and non-insertion of the driver into the driver groove.
Therefore, when the above-described capacitance adjusting method is applied to such a variable capacitor, a particularly remarkable effect is exhibited.

The present invention is applied to a variable capacitor in which a driver groove is formed in a rotor with a through hole. However, the rotor is made thinner, and thereby the variable capacitor is made thinner. In this case, it is advantageous that the shape of the driver groove cannot be complicated, and the driver groove can be simply formed with a through hole. Therefore, the present invention aims to make the rotor thinner,
This can be said to be particularly effective when trying to reduce the thickness of the variable capacitor.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a first embodiment of the present invention, showing a variable capacitor 1 in a state where a capacitance adjusting driver 21 is inserted.

FIG. 2 is a perspective view showing a bit section 22 of the capacitance adjusting driver 21 shown in FIG.

FIG. 3 is a perspective view corresponding to FIG. 2, showing a bit portion 32 of a capacitance adjusting driver 31 according to a second embodiment of the present invention.

FIG. 4 is a perspective view corresponding to FIG. 2, showing a bit section of a capacitance adjusting driver 41 according to a third embodiment of the present invention.

FIG. 5 is a perspective view corresponding to FIG. 2, showing a bit section 52 of a capacitance adjusting driver 51 according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating the variable capacitor 1 in a state in which a capacitance adjusting driver 12 is inserted, for explaining a technique interesting to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Variable capacitor 2 Stator 3 Rotor 4 Cover 5 Stator electrode 9 Dielectric layer 10 Rotor electrode 21, 31, 41, 51 Capacitance adjustment driver 22, 32, 42, 52 Bit part 23, 33, 43, 53 Tip surface 44 protrusion

Claims (8)

[Claims] 1. A stator forming a stator electrode,
It is arranged to be in contact with the stator,
A rotor electrode facing the stator electrode via a dielectric is formed, and the rotor electrode is rotatable with respect to the stator in order to adjust an electrostatic capacitance by changing an effective facing area of the rotor electrode with respect to the stator electrode. And a rotor provided with a driver groove for rotating operation by a capacitance adjusting driver having a through hole, and a rotor, in order to adjust the capacitance of the variable capacitor. A driver which is used to rotate the rotor by being inserted into the driver groove, wherein a tip portion of the bit portion inserted into the driver groove is provided with a shape in which a center portion protrudes from a peripheral portion. A driver for adjusting the capacitance of a variable capacitor. 2. The capacitance adjusting driver for a variable capacitor according to claim 1, wherein the bit portion has a quadrangular prism shape, and the tip end surface forms a quadrangular pyramid. 3. The variable capacitance capacitor adjusting driver according to claim 1, wherein the tip surface forms a spherical surface. 4. The variable capacitance capacitor adjusting driver according to claim 1, wherein the tip end surface has a shape in which a projection is formed at the center of a flat surface. 5. The bit portion has a minus cross-sectional shape, and the tip surface intersects so as to project in a V-shape.
The driver for adjusting the capacitance of a variable capacitor according to claim 1, wherein the driver is defined by two surfaces. 6. The driver for adjusting the capacitance of a variable capacitor according to claim 1, wherein the bit portion is made of a material having a dielectric property. 7. A stator forming a stator electrode,
It is arranged to be in contact with the stator,
A rotor electrode facing the stator electrode via a dielectric is formed, and the rotor electrode is rotatable with respect to the stator in order to adjust an electrostatic capacitance by changing an effective facing area of the rotor electrode with respect to the stator electrode. A variable capacitor that is held as described above, and has a rotor groove provided with a through hole for a rotation operation by a capacitance adjusting driver, and a method for adjusting the capacitance of the variable capacitor. A bit portion inserted into the driver groove and used to rotate the rotor, wherein a tip portion of the bit portion inserted into the driver groove has a shape in which a center portion protrudes from a peripheral portion. A driver for capacitance adjustment is prepared, and the driver is rotated while inserting the bit portion of the driver into the driver groove. By Rukoto, rotating the rotor, comprising the steps, the electrostatic capacity adjusting method of the variable capacitor. 8. In the variable capacitor, the stator includes a dielectric layer formed so as to cover the stator electrode, the dielectric is provided by the dielectric layer, and the rotor is formed of a conductive material. 8. The method according to claim 7, wherein the rotor electrode is formed with a step that protrudes on a surface of the rotor that contacts the stator. 9.