JP2009135357A - Variable capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable capacitor extending its life as compared with a conventional one by reducing mechanical wear. <P>SOLUTION: In the variable capacitor, two positive and negative collection conductors 11, 12 are opposingly provided in a vacuum container 1, a plurality of fixed electrodes 13 are mounted onto the opposing surface of the collection conductors in parallel in a direction crossing the collection conductors, a plurality of movable electrodes 14 are disposed in parallel with the fixed electrodes without any contact with the fixed electrodes, the movable electrodes move in a direction in parallel with the collection conductors, and capacitance changes according to the area where the movable electrodes overlap with the fixed electrodes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable capacitor used in an oscillation circuit of a high power transmitter, a high frequency power supply for a semiconductor manufacturing apparatus, a tank circuit of an induction heating apparatus, or the like.

A conventional variable capacitor is shown in FIG. The variable capacitor shown in FIG. 4 includes a fixed current collecting conductor 51 on one surface of a vacuum vessel 50, and a movable current collecting conductor 52 provided in the vacuum vessel 50 so as to face the fixed current collecting conductor 51. Electrodes 53 and 54 are attached to the current collectors 51 and 52, respectively. These electrodes 53 and 54 are attached in a direction orthogonal to the current collecting conductors 51 and 52. The movable current collector 52 moves toward the fixed current collector 51, but the electrodes 53 and 54 are not in contact with each other. A movable lead 55 is fixed to the movable current collector 52, and an adjustment screw 56 is attached to the movable lead 55. By rotating the adjusting screw 56, the movable current collecting conductor 52 is moved, and the capacitance is changed according to the area where the movable electrode 54 and the fixed electrode 53 overlap. (For example, refer to Patent Documents 1 and 2).
JP-A-5-41335 JP 2000-58385 A

  However, since the variable capacitor has its capacitance changed by rotating the adjusting screw, there is a problem that the movable part is consumed due to, for example, wear of the adjusting screw, and mechanically shortens the life. In particular, when the current is increased, the load on the movable part is increased, and the shortening of the mechanical life becomes more remarkable. In addition, if the movable current collector cannot move normally due to the consumption of the movable part, the capacitance, which is a characteristic of the variable capacitor, cannot be changed. Since variable capacitors are relatively expensive, they cannot be easily replaced.

  The present invention has been made in view of the above problems, and provides a variable capacitor capable of reducing mechanical wear and extending the life of the conventional product.

In order to solve the above-mentioned problems, a variable capacitor according to the present invention is provided such that two positive and negative current collectors are opposed to each other in a vacuum vessel, and a direction perpendicular to these current collectors is provided on an opposing surface of these current collectors. A plurality of fixed electrodes are mounted in parallel, and a plurality of movable electrodes are disposed in parallel with the fixed electrodes without being in contact with the fixed electrodes, and the movable electrodes are moved in a direction parallel to the current collector, The capacitance is configured to change according to the area where the movable electrode and the fixed electrode overlap.
The variable capacitor according to the present invention is characterized in that the movable electrode is configured to move integrally.

  According to the present invention, with the above-described configuration, the current collecting conductor is not moved. Therefore, mechanical consumption of the current collecting conductor can be greatly reduced. As a result, it is possible to perform the variable operation of the capacitance, which is the original purpose, for a long period of time. Further, with the above configuration, the capacitance can be varied for a long time without being affected by the magnitude of the current.

FIG. 1 to FIG. 3 are configuration perspective views in a state where the operation of changing the capacitance of the variable capacitor according to the best mode for carrying out the invention can be understood. The variable capacitor according to this embodiment is provided with a hexahedral vacuum container 1. The actual vacuum vessel 1 includes a portion having a fixed electrode (hereinafter referred to as “fixed electrode arrangement portion”) and a portion in which the movable electrode operates (hereinafter referred to as “movable electrode operation portion”). For convenience of explanation, FIGS. 1 to 3 do not show a portion where the movable electrode operates.

  1 and 3 are provided with two positive and negative current collectors 11 and 12 facing each other on the plane and bottom surface of the vacuum vessel 1. A plurality of fixed electrodes 13 are attached from the opposing surfaces of the current collectors 11 and 12 so as to be integrated. The fixed electrodes 13 are orthogonal to the current collectors 11 and 12, and the fixed electrodes 13 are parallel to each other. Further, a fixed electrode 13 is disposed so that a gap is formed in a central portion parallel to the two current collecting conductors 11 and 12 of the vacuum vessel 1.

  The variable capacitor is characterized in that the capacitance changes according to the area where the movable electrode and the fixed electrode 13 overlap. The movable electrode 14 according to the present embodiment is as follows. It is configured. First, a single plate-like body 15 is provided so as to be parallel to the two current collectors 11, 12, and a plurality of movable electrodes 14 are attached from both sides of the plate-like body 15, so that the movable electrodes 14 are integrally formed. It is configured to move. These movable electrodes 14 are attached so that the movable electrodes 14 are parallel to each other in a direction orthogonal to the current collectors 11 and 12. Further, these movable electrodes 14 are arranged so as not to contact the fixed electrode 13 and to be parallel to the fixed electrode 13.

The variable capacitor according to the present embodiment is configured as described above and operates as follows. First, the capacitance of the variable capacitor according to the present invention changes in capacitance according to the area where the movable electrode 14 overlaps the fixed electrode 13. Specifically, the capacitance in the container 1 is C (F), the dielectric constant of vacuum is ε ₀ (= 8.9 × 10 ⁻¹² (F / m)), the fixed electrode 13 and the movable electrode 14. And S (m ² ), and the distance between the leading edge of the movable electrode 14 and the leading edge of the fixed electrode 13 is d (m), the capacitance C (F) is Become.

  That is, the capacitance increases as the area where the fixed electrode 13 and the movable electrode 14 overlap increases, and the capacitance decreases as the distance between the leading edge of the movable electrode 14 and the leading edge of the fixed electrode 13 increases. .

  Subsequently, an aspect by the movement of the movable electrode 14 will be described. First, the case where all the movable electrodes 14 are in the fixed electrode arrangement part of the vacuum vessel 1 will be described. This is as shown in FIG. In this case, as is clear from Equation 1, the area where the fixed electrode 13 and the movable electrode 14 overlap is the largest, and the distance between the leading edge of the movable electrode 14 and the leading edge of the fixed electrode 13 is the shortest. Therefore, the capacitance is the largest.

  Next, a case where the electrostatic capacity is neither maximum nor minimum, that is, a case where a part of the movable electrode 14 is provided in the fixed electrode arrangement portion of the vacuum vessel 1 will be described. This is as shown in FIG. As described above, the capacitance changes according to the area where the movable electrode 14 overlaps the fixed electrode 13.

  Subsequently, the case where all the movable electrodes 14 come out of the fixed electrode arrangement portion of the vacuum vessel 1 and are included in the movable electrode operation portion of the vacuum vessel 1 will be described. This is as shown in FIG. In this case, as is clear from Equation 1, the area where the fixed electrode 13 and the movable electrode 14 overlap is the smallest, and the distance between the leading edge of the movable electrode 14 and the leading edge of the fixed electrode 13 is the longest. Therefore, the capacitance is the smallest.

  Since the variable capacitor is configured as described above, the capacitance is not changed by rotating the adjustment screw as in the past, so that it is almost impossible to wear out mechanically and the capacitance can be changed. The operation can be performed for a long time. Further, with the above configuration, the capacitance can be varied for a long time without being affected by the magnitude of the current.

  In addition, this invention is not limited to the said Example, The content as described in the claim belongs to the technical scope of this invention.

  According to the present invention, since the current collecting conductor is structured not to move, the mechanical consumption of the current collecting conductor can be greatly reduced. As a result, it is possible to perform the variable operation of the capacitance, which is the original purpose, for a long period of time. Further, with the above configuration, the capacitance can be varied for a long period of time without being affected by the magnitude of the current, which is industrially applicable.

It is a perspective view which shows the structure of the best form for implementing invention in the variable capacitor based on this invention. FIG. 7 is a configuration diagram showing another operation of the variable capacitor shown in FIG. 1. FIG. 7 is a configuration diagram showing another operation of the variable capacitor shown in FIG. 1. It is a block diagram which shows an example in the conventional variable capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum container 11, 12 Current collector 13 Fixed electrode 14 Movable electrode 15 Plate

Claims (2)

Provide two positive and negative current collectors in the vacuum container so as to face each other, and attach a plurality of fixed electrodes in parallel to the opposite surfaces of these current collectors in a direction perpendicular to these current collectors. In addition, a plurality of movable electrodes are arranged in parallel to the fixed electrode, and these movable electrodes move in a direction parallel to the current collector, and are electrostatically charged according to the area where the movable electrode and the fixed electrode overlap. A variable capacitor characterized in that the capacitance is changed. The variable capacitor according to claim 1, wherein the movable electrode is configured to move integrally.

Images