JP3365079B2 - Vacuum condenser - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum capacitor used for an oscillation circuit of a high power transmitter, a high frequency power supply for a semiconductor manufacturing apparatus, or a tank circuit of an induction heating apparatus. About. 2. Description of the Related Art FIG. 3 is a sectional view of the basic structure of a conventional general variable vacuum capacitor. For example, copper cylindrical tubes 11a and 11b are joined to both ends of an insulating cylinder 12 made of ceramic or the like. A cylindrical portion is formed, and the cylindrical portion is closed by a fixed-side end plate / fixed electrode mounting conductor 13 and a movable-side end plate 14 to form a vacuum vessel 10 for accommodating a capacitor portion. Inside the fixed electrode mounting conductor 13, a plurality of cylindrical electrode plates F ₁ , F _2, ..., F _n having different diameters (radius) are mounted concentrically at regular intervals to form a fixed electrode 15. Further, a plurality of cylindrical electrode plates M ₁ , M ₂ ... _Mn having different inner diameters are connected to the movable electrode mounting conductor 18 so that the fixed electrode 15 can be inserted into and removed from each electrode plate in a non-contact state. To form the movable electrode 16. A movable lead 1 is attached to the movable electrode mounting conductor 18.
The movable lead 18 ′ is non-rotatably supported by a bearing 17 provided through the movable end plate 14 so as to be vertically movable without moving. The movable electrode 16 is axially moved from the outside of the vacuum vessel in the axial direction. Move. Reference numeral 19 denotes 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 end plate 18, and a sliding portion between the bearing 17 and the movable lead 18 ′. In addition, the penetrating portion of the movable side end plate 14 of the bearing 17 is covered so that the movable lead can be moved up and down while preventing vacuum leakage. [0005] The cylindrical portion of the vacuum vessel 10 may be formed entirely 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. When adjusting the capacitance of the vacuum capacitor configured as described above, a voltage is applied to the movable electrode and the fixed electrode, and the movable lead 18 'is moved by the capacitance adjusting means (see FIG. 4). By moving the fixed electrode 15 and the movable electrode 16 in the axial direction of the lead, the facing area of the fixed electrode 15 and the movable electrode 16 is changed.
The value of the capacitance generated between 16 is continuously changed. When the capacitance is adjusted as described above, the movable electrode 16 is moved in the axial direction of the movable lead to vary the area facing the fixed electrode 15. That is, the movable electrode must be moved while keeping a plurality of cylindrical electrode plates having different diameters in a non-contact state with each other and keeping a constant interval. That is, since the distance between the cylindrical electrode plates on the fixed side and the movable side is narrow, it is necessary to move the movable electrode in a non-contact state while maintaining the parallel state.
And the dimensional tolerance of the movable lead 18 'must be strict. If the tolerance is loose, the sliding part between the movable lead and the bearing is located at a position (lower side) away from the cylindrical electrode plate, so that even the slight gap between the movable lead and the bearing, the inclination of the movable cylindrical electrode plate can be reduced. Becomes large, and the capacitance and the withstand voltage characteristics become unstable. Therefore, if the tolerance of the sliding portion between the movable lead and the bearing is made strict, this sliding portion is in the atmosphere, so that there is a problem that the slidability is hindered by intrusion of dust and dirt. In addition, as shown in FIG. 4, the applicant of the present application has provided the guide pin 1 (or the guide portion 5) and the movable electrode axial portion of the movable electrode The above problem has been solved by providing a guide portion 5 (or guide pin 1) for inserting and guiding a guide pin. [0010] That is, the concentric portions of the cylindrical electrode plate F ₁ to F _n at the inside of the fixed electrode mounting conductor 13, provided with a guide pin 1 along the axis of the cylindrical electrode plates, the movable electrode mounting conductor 18 side A guide portion 5 having a guide pin insertion hole for inserting the guide pin 1 is provided to form a guide portion, and the guide pin is slidably inserted into the guide pin insertion hole while maintaining electrical insulation. The movable cylindrical electrode plate is moved while keeping a fixed distance from the fixed cylindrical electrode plate, and the withstand voltage and electrostatic force caused by the inclination of the movable lead are maintained. This eliminates the instability of capacity. The above-mentioned guide portion 5 is formed integrally with the movable lead 2, but may be provided separately on the movable electrode mounting conductor 18. 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. Must be performed so as not to hinder To do so, one of the guide pin 1 and the guide portion 5 must be made of an insulating material.
The guide pin 1 is made of ceramic to maintain smooth sliding.
In particular, it is preferable that the guide portion 5 is formed of ceramics made of alumina and the guide portion 5 is formed of phosphor bronze. Also, the guide pin 1 is made of metal and the surface thereof is coated with a highly slippery nylon resin to maintain insulation. However, smooth sliding can be ensured. FIG. 4 is a sectional view of an example in which the capacitance adjusting means 20 is provided. The capacitance adjusting means 20 includes a screw portion 2c formed on the free end 2a side of the movable lead and a screw portion 2c. 2c
Adjusting screw 23 having a screw portion 23a screwed into
And a screw receiving portion 21 for capacitance adjustment, one end of which is attached to the movable side end plate 14. The other end of the screw receiving portion 21 is rotatably connected to the other end via a thrust bearing 22. Attach the adjusting screw 23. Reference numeral 23b denotes an operation section of the adjusting screw 23, which rotates the operation section 23b manually or by a motor to move the movable electrode 16 up and down via the movable lead 2. Means for making the movable lead 2 non-rotatable and vertically movable is a general means such as providing 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. As shown in FIG. 4, a movable electrode mounting conductor 18 to which cylindrical electrode plates M _{1 to} M _n are mounted is provided at the center of a cylindrical electrode plate in a vacuum vessel. Since the movable electrode 16 is guided and moved by the guide pin, the movable electrode 16 can move accurately in the axial direction of the movable lead 2, and since the guide portion is in the vacuum vessel, there is no intrusion of dust and dirt. It exerts excellent effects such that the mobility is not impaired. However, at the stage of commercialization, the development of small and inexpensive products is always pursued. In the case of the vacuum capacitor shown in FIG. 4, the maximum capacitance is the position where the movable electrode 16 has entered the deepest inside the fixed electrode 15, and the tip 1a of the guide pin 1 is Is determined by the position where the hole abuts on the bottom 3a. The minimum capacitance is adjusted by rotating the adjusting screw 23 to move the movable lead 2 downward,
Is determined at a position where it abuts against the bottom surface 21 a of the screw receiving portion 21. Therefore, when a variable (adjustable) range of the capacitance is required to be wide, the moving distance l 'of the movable lead 2 becomes longer, and the screw 23 is used to move the movable lead 2 by l'.
a, the distance l between the tip 23c and the movable lead bottom 2b is l ≧
l ', and a space of 2 l' is required in the full length direction of the vacuum capacitor, and the problem that the total length becomes longer remains. Therefore, an object of the present invention is to reduce the total length of the vacuum capacitor to reduce the cost. Means for solving the above problems in the present invention are a vacuum vessel having a fixed end plate at one end of a cylindrical portion and a movable end plate at the other end. A fixed electrode formed by concentrically attaching a plurality of concentric circular electrode plates having different diameters to a fixed electrode mounting conductor in the vacuum vessel, and a non-contact state between each of the cylindrical electrode plates of the fixed electrode. A movable electrode formed by attaching a plurality of cylindrical electrode plates having different diameters concentrically to a movable electrode mounting conductor so that the movable electrode can be inserted into and removed from the movable electrode; A movable lead that moves in the axial direction of the plate, a bellows provided on the outer peripheral side of the movable lead inside the movable side end plate and capable of moving the movable lead while maintaining a vacuum state, and the fixed electrode Mounting conductor and movable electrode mounting conductor A vacuum capacitor comprising: a guide portion formed by a guide pin provided at a center portion of the opposing surfaces, and a guide portion for electrically insulating and slidably inserting the guide pin. A movable lead bolt is axially attached to the tip of the movable lead in the bellows, and the movable end plate is provided with a screw receiving portion projecting into the bellows inside thereof, and a bearing is attached to the end thereof,
The movable lead bolt is screwed into an adjusting nut supported by a bearing to adjust the capacitance of the upper capacitor by rotating the adjusting nut. According to the present invention, as described above, the movable lead bolt is directly connected to the movable lead within the bellows.
The screw receiving portion can be arranged in the bellows inside the movable end plate, and the moving distance l of the movable lead bolt is until the movable lead bolt connecting portion 32a hits the bottom outer surface 31a of the screw receiving portion. The parts 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, so that downsizing can be realized. The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 is a block diagram of an embodiment of the present invention, and shows a vertical sectional front view. The same or corresponding parts as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 1, reference numeral 31 denotes a screw receiving portion. The screw receiving portion 31 is provided upright on the inner side of the movable side end 14 and has a flange portion 31a at an inner end portion. Reference numeral 32 denotes a movable lead bolt having a screw threaded on the outer circumference, one end of which is attached to the distal end of the shortened movable lead 2, and the other end of which passes through the gap in the flange 31a along the axis. It protrudes into the screw receiving portion 31. 33 is an adjustment nut, which is a movable lead bolt 3
2 has a screw hole into which a screw receiving portion 31 is screwed.
It is screwed into the end of the movable lead bolt 32 protruding inward, is rotatably attached to the inner bottom of the flange 31a via a bearing such as a bearing 34, and is rotated by the capacitance adjusting means. This capacitance adjusting means is manually or by the means shown in FIG. FIG. 2 shows another embodiment of the screw receiving portion 31 in which (A) is formed integrally with the movable end plate 14 and (B) is formed.
Shows an example in which it is attached to the inner surface of the movable side end plate 14,
It may be attached by any method. Also, a plurality of inverted L-shaped mounting pieces may be formed upright on the movable side end plate. The capacitance can be adjusted by rotating the adjustment nut 33.
2 moves downward, and when rotated left, moves upward, moves the movable electrode 16 up and down, and changes the area facing the fixed electrode 15 to adjust the capacitance. In the vacuum capacitor, a force that constantly pushes the movable lead bolt 32 upward (to the fixed electrode side) acts due to the pressure difference from the vacuum, and the adjusting nut 33 screwed to the movable lead bolt 32 also exerts the force. Receiving, screw receiving part 3
1 has a surface pressure, and to rotate the adjustment nut 33,
Although a large rotating torque is required, in the present invention, since the bearing 33 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. Further, since the screw receiving portion 31 is arranged in the direction inside the vacuum condenser with respect to the movable side end plate 14, the moving distance l of the movable lead bolt 32 is limited to the flange portion 31 of the screw receiving portion.
Until the connecting portion 32a of the movable lead bolt 32 abuts against the outer surface 31a of FIG. 4, the distance l 'in FIG. 4 is unnecessary. Although the bellows 19 is mounted on the movable lead 2 in the embodiment of FIG. 1, it may be mounted on the movable electrode mounting conductor 18, and the guide portion 5 is formed integrally with the movable lead 2. In some cases, it may be provided integrally with or separately from the movable electrode mounting conductor. The guide pin 1 may be attached to the movable electrode attachment conductor side, and the guide portion may be attached to the fixed end plate 13 side. As described above, according to the present invention, the total length of the vacuum capacitor can be shortened, and the apparatus for housing the vacuum capacitor and the entire apparatus can be downsized, thereby reducing the cost of the apparatus as a whole. I can do it. And the like.

[Brief description of the drawings] FIG. 1 is a configuration diagram of a first embodiment of the present invention. FIG. 2 is a sectional view of an embodiment of the screw receiving portion of the present invention. FIG. 3 is a basic configuration diagram of a vacuum capacitor. FIG. 4 is a configuration diagram for explaining the present invention. [Explanation of symbols] 1. Guide pin 2. Movable lead 2a: Free end 5… Guide part 3. Guide insertion hole 10. Vacuum container 13: Fixed electrode mounting conductor 14 movable end plate 15: Fixed electrode 16 ... Movable electrode 18. Movable electrode mounting conductor 19 ... Bellows 20 ... Capacitance adjustment means 21 Screw receiving part 23 ... Adjustment screw 23a: Screw part 23b ... operation unit 31 ... screw receiving part 32… Movable lead bolt 33 ... Adjustment nut 34 ... Bearing

Claims (1)

(57) [Claim 1] A vacuum vessel having a fixed end plate at one end of a cylindrical portion and a movable end plate at the other end thereof, and a concentric circular diameter plate inside the vacuum vessel. A fixed electrode formed by concentrically attaching a plurality of different cylindrical electrode plates to a fixed electrode mounting conductor, and a plurality of cylinders having different diameters so that the fixed electrode can be inserted into and removed from each cylindrical electrode plate in a non-contact state. A movable electrode formed by concentrically attaching the shaped electrode plate to the movable electrode mounting conductor, a movable lead for moving the movable electrode from outside the movable end plate of the vacuum vessel in the axial direction of the cylindrical electrode plate, A bellows provided on the outer peripheral side of the movable lead and inside the movable side end plate and capable of moving the movable lead while maintaining a vacuum state, and opposing surfaces of the fixed electrode mounting conductor and the movable electrode mounting conductor Guide pins provided at the center of What is claimed is: 1. A vacuum capacitor comprising: a guide portion formed by a guide portion for slidably inserting an electrically insulated doping pin, wherein a movable lead bolt is axially attached to a tip end of a movable lead in the bellows. The movable end plate is provided with a screw receiving portion protruding into the bellows inside thereof, a bearing is attached to the end thereof, and the movable lead bolt is screwed into an adjusting nut supported by the bearing. A vacuum capacitor wherein the capacitance of the upper capacitor is adjusted by rotating the adjusting nut.