JPH0897088A - Vacuum capacitor - Google Patents

Abstract

PURPOSE: To achieve a stabilized maximum voltage and capacitance characteristics by shifting a fixed electrode and a movable electrode comprising tubular electrode plates in the axial direction without inclining on the movable electrode side and to regulate the fluctuation by making the maximum capacitance adjustable while reducing the size. CONSTITUTION: One of the conductors 13, 18 for fixing fixed and movable electrodes, respectively, is provided with a guide pin 1 while the other conductor is provided with a guide part 5 so that the electrode plates can be shifted with no inclination. A capacitance adjusting part is provided in a bellows 19 in order to shorten the overall length and a maximum capacitance regulating part 35 is provided at a part where an adjusting nut 33 is screwed to a movable lead bolt 32. The maximum capacitance is adjusted to a defined value and then the position is fixed by means of an adjusting screw 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum capacitor used in an oscillation circuit of a high power transmitter, a high frequency power source for semiconductor manufacturing equipment, a tank circuit of an induction heating device, or the like.

[0002]

2. Description of the Related Art FIG. 3 is a cross-sectional view of the basic structure of a conventional general variable type vacuum capacitor. For example, cylindrical cylinders 11a and 11b made of copper are joined to both ends of an insulating cylinder 12 made of ceramic or the like. The cylindrical portion is closed by the fixed-side end plate / fixed electrode mounting conductor 13 and the movable-side end plate 14 to form the vacuum container 10 for housing the capacitor portion.

Inside the fixed electrode attachment conductor 13, a plurality of cylindrical electrode plates F ₁ , F ₂ ... F _n having different diameters (radii) are concentrically attached at regular intervals to form a fixed electrode 15. In addition, a plurality of cylindrical electrode plates M ₁ , N ₂ ... M _n having different inner diameters are attached to the movable electrode mounting conductor 18 so that they can be inserted and removed in a non-contact state in the gaps between the electrode plates of the fixed electrode 15. And the movable electrode 16 is formed.

The movable electrode mounting conductor 18 has a movable lead 1
8'is provided, and this movable lead 18 'is supported by a bearing 17 penetrating the movable side end plate 14 so as to be non-rotatable and vertically movable, and to move the movable electrode 16 from the outside of the vacuum container in the axial direction. To move. Reference numeral 19 is a bellows, one end of which is brazed to the movable end plate 14 and the bearing 17, and the other end of which is brazed to the movable lead 18 'or the movable conductor 18, and the sliding portion between the bearing 17 and the movable lead 18' and the bearing. The penetrating portion of the movable end plate 14 of 17 is covered so that the movable lead can move up and down while preventing vacuum leakage.

The entire cylindrical portion of the vacuum container 10 may be formed of an insulating cylinder made of ceramic or the like. The point is that the fixed electrode and the movable electrode may be electrically insulated.

In the case of adjusting the electrostatic capacity of the capacitor thus constructed, the movable lead and the fixed electrode are energized, and the movable lead 18 'is adjusted by the electrostatic capacity adjusting means (see FIG. 4).
By moving the movable lead in the axial direction of the movable lead by the fixed electrode 15
By changing the facing area between the movable electrode 16 and the movable electrode 16.
The value of capacitance generated between them is continuously changed.

When the electrostatic capacitance is adjusted as described above, the movable electrode 16 is moved in the axial direction of the movable lead to change the facing area with the fixed electrode 15, and the fixed electrode and the movable electrode are adjusted. That is, it is necessary to move the movable electrode while keeping a constant interval in a state where a plurality of cylindrical electrode plates having different diameters are not in contact with each other.

That is, since the space between the fixed side and the movable side cylindrical electrode plates is narrow, it is necessary to move the movable electrode in a non-contact and parallel state. Therefore, the bearing 17
It is necessary to tighten the dimensional tolerance of the movable lead 18 '. If the tolerance is loose, the sliding parts of the movable lead and the bearing are located away from the cylindrical electrode plate (lower side), so even if there is a slight gap between the movable lead and the bearing, the inclination of the movable side cylindrical electrode plate Becomes large and the capacitance and withstand voltage characteristics become unstable.

Therefore, if the tolerance of the sliding portion between the movable lead and the bearing is tightened, the sliding portion is in the atmosphere, so that the slidability is impeded by the intrusion of dust or the like. Therefore, the applicant of the present application, as shown in FIG. 4, includes a guide pin 1 (or a guide portion 5) at the fixed electrode shaft center portion of the fixed electrode attachment conductor 13 and a movable electrode shaft center portion of the movable electrode attachment mount conductor 18, The above problem is solved by providing the guide portion 5 (or the guide pin 1) for inserting and guiding the guide pin.

That is, inside the fixed-side electrode mounting conductor 13, concentric portions of the cylindrical electrode plates F _{1 to} F _n are provided with the guide pins 1 along the axis of the cylindrical electrode plate and the movable electrode mounting conductor 18 side. Is provided with a guide portion 5 having a guide pin insertion hole 3 into which the guide pin 1 is inserted to form a guide portion, and the guide pin 1 is slidably inserted into the guide pin insertion hole 3 while maintaining electrical insulation. , The movable electrode is guided by a guide pin to be moved, and the movable side cylindrical electrode plate is moved while maintaining a fixed distance from the fixed side cylindrical electrode plate,
This eliminates the instability of withstand voltage and electrostatic capacitance due to the inclination of the movable lead. Although the guide portion 5 is formed integrally with the movable lead 2, the movable electrode mounting conductor 1
8 may be separately provided.

Since the fixed electrode 15 and the movable electrode 16 must be electrically insulated, the guide pin 1 and the guide portion 5 must be electrically insulated.
This insulating means must be provided so as not to impair the smoothness of sliding. For that purpose, either the guide pin 1 or the guide portion 5 must be made of an insulating material. In order to keep the slidability smooth, it is preferable that the guide pin 1 is made of ceramics, especially ceramics made of alumina, and the guide portion 5 is made of phosphor bronze. Even if it is coated with nylon resin, which has excellent lubricity, it is possible to ensure smooth sliding while maintaining insulation.

FIG. 4 is a cross-sectional view of an example in which the capacitance adjusting means 20 is provided. The capacitance adjusting means 20 has a threaded portion 2c formed on the free end 2a side of the movable lead and this threaded portion. 2c
Capacitance adjusting screw 23 having a screw portion 23a screwed to
And a screw receiving portion 21 having one end side attached to the movable side end plate 14 for capacitance adjustment, and the other end side of the screw receiving portion 21 is rotatably provided with an electrostatic capacitance via a thrust bearing 22. Attach the adjusting screw 23. Reference numeral 23b is an operation portion of the adjusting screw 23, and the operation portion 23b is rotated manually or by a motor or the like to move the movable electrode 16 up and down through the movable lead 2.

The means for making the movable lead 2 non-rotatable and movable up and down is generally a key groove on one of the sliding surfaces of the guide pin 1 and the guide portion 5, and a key on the other. It can be realized by means.

[0014]

A guide guide pin provided with a movable electrode mounting conductor 18 to which cylindrical electrode plates M _{1 to} M _n are mounted as shown in FIG. 4 is provided at the center of the cylindrical electrode plate in a vacuum container. Since the movable electrode 16 can be moved accurately in the axial direction of the movable lead 2 because it is guided by and is moved in the axial direction of the movable lead 2, and since the guide portion is in the vacuum container, dust and dirt do not enter and slidability is also hindered. It has excellent effects such as being prevented from being damaged.

However, there are always some problems to be solved at the stage of commercialization.

In the case of the vacuum capacitor shown in FIG. 4, the maximum capacitance is the position where the movable electrode 16 penetrates deepest into the fixed electrode 15, and the tip 1a of the guide pin 1 has the guide pin insertion hole 3 therein. It is determined by the position where it hits the hole bottom 3a.

In addition, the minimum electrostatic capacitance is obtained by rotating the adjusting screw 23 to move the movable lead 2 downward, and the free end 2a thereof.
Is determined by the position where it abuts the bottom surface 21a of the screw receiving portion 21.

Therefore, when the variable (adjustment) range of the capacitance is required to be wide, the moving distance l'of the movable lead 2 becomes long, and the screw portion 23 is used to move the movable lead 2 by 1 '.
The distance l between the tip portion 23c of a and the movable lead bottom portion 2b is set to l ≧
It is necessary to set the length to l ', and a space of 2l' is required in the lengthwise direction of the vacuum capacitor, which leaves a problem that the total length becomes long.

Further, in this type of vacuum capacitor, the electrostatic capacitance C of the coaxial cylindrical electrode is C = (ε ₀ l) / (l
ogb / a), the vacuum capacitor has a large number of coaxial cylindrical electrodes facing each other, and the value obtained by adding each of the above equations becomes the capacitance value.

In the above equation, ε ₀ is the inductivity of vacuum, a is the outer diameter of the inner and outer electrodes, b is the inner diameter of the outer electrode, and l is the intersecting length.

However, even if the vacuum capacitors are manufactured according to the same specifications, the electrostatic capacitance values will be slightly different due to the deviation of the true circularity of the cylindrical electrodes or the error due to the arrangement.

There is also a problem that the maximum capacitance value varies due to the total length error of the guide pin 1.

In view of the above points, the present invention reduces the total length of the vacuum capacitor to reduce the cost, and
An object of the present invention is to provide a vacuum capacitor of uniform quality by adjusting the maximum capacitance value of the manufactured vacuum capacitor.

[0024]

Means for Solving the Problems According to the present invention, means for solving the above-mentioned problems include a vacuum container having a fixed side end plate on one end side and a movable side end plate on the other end side, and the vacuum container. A fixed electrode formed by concentrically mounting a plurality of concentric cylindrical electrodes with different diameters on a fixed electrode mounting conductor and the cylindrical electrode plates of this fixed electrode can be inserted / removed in a non-contact state. A movable electrode formed by concentrically mounting a plurality of cylindrical electrode plates having different diameters on a movable electrode mounting conductor, and the movable electrodes from outside the movable side end plate of the vacuum container in the axial direction of the cylindrical electrode plate. Movable lead, a bellows provided on the outer peripheral side of the movable lead inside the movable side end plate to allow movement of the movable lead while maintaining a vacuum state, and the fixed electrode mounting conductor and movable Of the opposite surfaces of the electrode mounting conductor A vacuum capacitor comprising a guide portion formed by a guide pin provided in each core portion and a guide portion into which the guide pin is electrically insulated and slidably inserted, and a movable lead in the bellows. A movable lead bolt is attached to the tip end of the movable end bolt in the axial direction, and the movable side end plate is provided with a screw receiving portion projecting into the bellows inside thereof, and a bearing is provided at the end portion of the movable side end plate. The adjustment nut supported by the screw is used to adjust the electrostatic capacitance of the capacitor by rotating the adjustment nut, and the adjustment nut is operated at the screwed portion of the movable lead bolt and the adjustment nut. After adjusting to the defined maximum capacitance value, maximum capacitance adjusting means for restricting the movement of the movable lead bolt to the guide pin side at this adjustment position is provided.

The maximum capacitance adjusting means is provided with a screw hole at the tip of the movable lead bolt, and the adjusting nut is provided with a large diameter portion having a diameter larger than the screw hole into which the movable lead bolt is screwed. An adjusting screw is inserted from the large diameter portion so as to be screwed into the screw hole at the tip of the movable lead bolt.

[0026]

As described above, according to the present invention, the movable lead bolt is directly connected to the movable lead in the bellows.
It becomes possible to dispose the screw receiving portion in the bellows inside the movable side end plate, and the moving distance l of the movable lead bolt is such that the connecting portion 32a of the movable lead bolt 32 abuts the outer surface 31a of the bottom of the screw receiving portion. Therefore, the adjusting portion can be arranged in the fixed side end plate (fixed electrode mounting conductor 13) and the movable side end plate 14 of the vacuum capacitor, and the downsizing can be realized.

When adjusting the maximum capacitance value of the vacuum capacitor, first, before the adjusting screw 36 is screwed in and fixed, the adjusting nut 33 is turned slightly to the right to guide the guide pin 1.
The movable lead 2 is slightly moved downward from the position of the maximum capacitance where the tip 1a of the above and the end surface 32b of the connecting portion 37 of the movable lead bolt 32 abut, and the maximum capacitance (design value) is defined. This slight movement distance is determined by the degree of variation in the vacuum capacitor electrostatic capacitance.

Next, in this state, the adjusting screw 36 is inserted from the large diameter portion 33a of the adjusting nut 33, receives the step portion 33b, and receives the screw hole 32a at the tip portion of the movable lead bolt 32.
Then, the adjusting screw 36 is fixed to the tip of the movable lead bolt 32 with an adhesive or the like, and the maximum capacitance value of each vacuum capacitor is fixed to the defined maximum capacitance value.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1 is a configuration diagram of an embodiment of the present invention, showing a vertical sectional front view. Note that the same parts as or the corresponding parts to those in FIG.

In FIG. 1, reference numeral 31 denotes a screw receiving portion, the screw receiving portion 31 is provided upright inside the movable side end 14, and a flange portion 31a is provided at the inner end portion. Reference numeral 32 is a movable lead bolt having a screw threaded on its outer periphery, one end side of which is attached to a connecting portion 37 at the tip portion of the movable lead 2 which is shortened, and the other end side of which is a void in the collar portion 31a along the axis. Through the screw receiver 31
It is projected inside. An adjustment nut 33 has a screw hole 33c into which the movable lead bolt 32 is screwed, one end side of which is screwed into the end of the movable lead bolt 32 protruding into the screw receiving portion 31, and a bearing 34 such as a bearing. Through the collar 31
It is rotatably attached to the inner bottom of a. Reference numeral 35 denotes a maximum capacitance adjusting section (means), which is the maximum capacitance adjusting section 35.
As shown in the enlarged view of FIG.
A screw hole 32a at the tip of the screw, an adjusting screw 36 screwed into the screw hole 32a, an adjusting nut 33, and a movable lead bolt 32.
A large-diameter portion 33a having a larger diameter than the screw hole 33c into which the movable lead bolt 32 is screwed, and a large-diameter portion 33a formed so that the adjusting screw 36 can be inserted into the adjusting nut 33 at the screw-engaged portion with the large-diameter portion. 33a and a step portion 33b at the boundary between the screw holes 33c.

When adjusting the maximum capacitance value of the vacuum capacitor, first, the adjusting nut 33 is turned slightly to the right (in the case of a right screw) before the adjusting screw 36 is screwed in and fixed, and the tip of the guide pin 1 is adjusted. Connection part 37 between 1a and movable lead bolt 32
The movable lead 2 is slightly moved downward from the position of the maximum capacitance with which the end surface 32b of the above abuts to adjust it to the defined maximum capacitance value. This slight adjustment amount is determined by the degree of variation in the electrostatic capacitance of the vacuum capacitor.

Next, in this state, the adjusting screw 36 is screwed into the screw hole 32a until the contact surface of the head of the adjusting screw 36 comes into contact with the stepped portion 35b. The movable lead bolt 32 is fixed to the bolt 32 with an adhesive or the like to regulate the rising position of the movable lead bolt 32 (not bonded to the adjustment nut).

By thus regulating the rising position of the movable lead bolt 32, the maximum capacitance value can be adjusted for each vacuum capacitor even if the produced vacuum capacitors have variations in the maximum capacitance value. , A vacuum capacitor of a quality that meets the defined maximum capacitance value is obtained.

Further, the adjusting screw 36 hits the stepped portion 33b even if the adjusting nut 33 is rotated to the left from the position of the maximum capacitance value, and the adjusting screw 36 does not rotate further to the left. It also has the function of a stopper that prevents it from coming off from the movable lead bolt.

To adjust the electrostatic capacity of the vacuum capacitor, by rotating the adjusting nut 33, for example, the movable lead bolt 32 moves downward in the right rotation, moves upward in the left rotation, and moves the movable electrode 16 up and down. Then, the total area facing the fixed electrode 15 is varied to arbitrarily adjust the capacitance. This adjusting means is manual or by the electrostatic capacity adjusting means of FIG.

In the vacuum capacitor, a force that always pushes the movable lead bolt 32 upward (to the fixed electrode side) acts due to the pressure difference from the vacuum, and the adjustment nut 33 screwed to the movable lead bolt 32 also exerts the force. Receiving the screw receiving part 3
In order to rotate the adjusting nut 33, a surface pressure is generated on
Although a large rotating torque is required, in the present invention, since the bearing 33 such as a bearing is mounted between the adjusting nut 33 and the screw receiving portion 31, the rotating operation of the adjusting nut 33 can be performed with a small rotating torque. Become.

Further, since the screw receiving portion 31 is arranged inward of the vacuum condenser with respect to the movable side end plate 14, the moving distance l of the movable lead bolt 32 is movable to the outer surface 31a of the flange portion 31 of the screw receiving portion. The connecting portion 32a of the lead bolt 32 comes into contact with each other, and the distance l'in FIG. 4 becomes unnecessary.

Although the bellows 19 is attached to the movable lead 2 in the embodiment shown in FIG. 1, the movable electrode attachment conductor 1
8 may be attached to the movable lead 2.
However, it may be formed integrally with or separately from the movable electrode attachment conductor. Further, the guide pin 1 may be attached to the movable electrode attachment conductor side, and the guide portion may be attached to the fixed side end plate 13 side.

[0039]

As described above, according to the present invention, the total length of the vacuum condenser can be shortened, and accordingly, the apparatus for accommodating the vacuum condenser and the whole apparatus to be incorporated can be downsized, and the cost of the whole apparatus can be reduced.

Also, since the maximum capacitance value of the manufactured vacuum capacitor can be easily adjusted to match the defined maximum capacitance value, the maximum capacitance value can be made uniform by eliminating variations in the maximum capacitance value. It has excellent effects such as obtaining a vacuum capacitor having a capacitance value.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is an enlarged view of a maximum capacitance adjusting unit according to an embodiment of the present invention.

FIG. 3 is a basic configuration diagram of a vacuum capacitor.

FIG. 4 is a block diagram for explaining the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Guide pin 2 ... Movable lead 2a ... Free end part 3 ... Guide insertion hole 5 ... Guide part 10 ... Vacuum container 13 ... Fixed electrode attachment conductor 14 ... Movable side end plate 15 ... Fixed electrode 16 ... Movable electrode 18 ... Movable electrode Mounting conductor 19 ... Bellows 20 ... Capacitance adjusting means 21 ... Screw receiving portion 23 ... Adjusting screw 23a ... Screw portion 23b ... Operating portion 31 ... Screw receiving portion 32 ... Movable lead bolt 33 ... Adjusting nut 34 ... Bearing 35 ... Maximum static Capacitance adjusting part 36 ... Adjusting screw 37 ... Connection part

Claims (2)

[Claims] 1. A vacuum container having a fixed end plate at one end of a cylindrical portion and a movable end plate at the other end, and a plurality of concentric circular electrode plates having different diameters fixed in the vacuum container. A fixed electrode that is concentrically attached to the electrode mounting conductor, and a plurality of cylindrical electrode plates with different diameters that can be inserted and removed in a non-contact state between the cylindrical electrode plates of this fixed electrode A movable electrode formed by being attached concentrically, a movable lead for moving the movable electrode from the outside of the movable end plate of the vacuum container in the axial direction of the cylindrical electrode plate, and the movable side on the outer peripheral side of the movable lead. A bellows, which is provided inside the end plate and allows the movable lead to move while maintaining a vacuum state, and guides provided at the central portions of the surfaces of the fixed electrode mounting conductor and the movable electrode mounting conductor which face each other. Pin, this guide pin is electrically isolated And a guide portion formed so as to be slidably inserted into the bellows, wherein a movable lead bolt is axially attached to a tip portion of the movable lead in the bellows, and the movable side end is provided. The plate is provided with a screw receiving portion projecting into the bellows on the inside thereof, and a bearing is provided at the end portion thereof, and the movable lead bolt is screwed into an adjusting nut supported by the bearing to rotate the adjusting nut. While adjusting the capacitance of the capacitor, the threaded portion of the movable lead bolt and the adjustment nut, after adjusting the maximum capacitance value defined by operating the adjustment nut,
A vacuum capacitor comprising maximum capacitance adjusting means for restricting the movement of the movable lead bolt toward the guide pin side at this adjustment position. 2. The maximum capacitance adjusting means is provided with a screw hole at the tip of the movable lead bolt, and the adjusting nut is provided with a large diameter portion having a diameter larger than the screw hole into which the movable lead bolt is screwed. 2. The vacuum capacitor according to claim 1, wherein an adjusting screw is inserted from a large diameter portion so as to be screwed into a screw hole at a tip of the movable lead bolt.