Vacuum capacitor

Abstract

A vacuum capacitor is provided with a vacuum container 1a that accommodates a fixed electrode 7 and a movable electrode 8 that can secure capacitance, and a vacuum expansion container 52 that communicates in series with the vacuum container 1a. The vacuum container 1a has: a movable support part 91 that supports the movable electrode 8; a movable conductor 6 that supports the movable support part 91 so as to be capable of reciprocating in the axial direction of the vacuum container 1a; a fixed conductor 51 that supports the fixed electrode 7; and a main bellows 50 that is interposed between the movable support part 91 and the movable conductor 6. The vacuum expansion container 52 is provided with a movable part 54 disposed coaxially with the movable support part 91, and an adjustment bellows 53 interposed between the movable part 54 and the inner end surface of the vacuum expansion container 52. The movable support part 91 and the movable part 54 are connected by an insulating connecting rod 55 disposed coaxially with the fixed electrode 7 and the movable electrode 8.

Description

Technical Field

[0001] The present invention relates to a vacuum capacitor which is used, for example, for adjusting the impedance of high-frequency equipment such as a high-power transmission circuit and a high-frequency power supply in semiconductor facilities. Background Art

[0002] Various vacuum capacitors have been used in high-frequency devices such as high-power transmission circuits and high-frequency power supplies in general semiconductor facilities for impedance adjustment. Recently, the operating speed of devices related to high-frequency devices has become faster and faster, and in order to support high-speed operation, there is an increasing demand for vacuum capacitors that reduce operating force.

[0003] Figure 2 1 is a schematic cross-sectional view showing an example of a general vacuum capacitor. A vacuum container 1 is formed into a cylindrical shape by a flange tube 3 at one end of an insulating ceramic tube 2 and a flange tube 4 at the other end, one of the two ends is sealed with a metal fixed conductor 5, and the other end is sealed with a metal movable conductor 6.

[0004] The fixed electrode 7 is composed of a plurality of thin cylindrical electrode members of different diameters, which are arranged at certain intervals on the same axis, and the fixed electrode 7 is arranged inside the vacuum container 1 of the fixed conductor 5. Similar to the fixed electrode 7, the movable electrode 8 is composed of a plurality of thin cylindrical electrode members of different diameters, which are arranged at certain intervals on the same axis. The respective electrode members of the movable electrode 8 are inserted and removed in a state of crossing the respective electrode members of the fixed electrode 7, and a small gap is ensured with the fixed electrode 7 to obtain capacitance. The movable electrode 8 is arranged on a movable support 9 made of a copper material, and the movable support 9 can adjust the degree of insertion and removal relative to the fixed electrode 7 in the axial direction Y of the vacuum container 1.

[0005] The hollow movable rod 10 is provided to extend from the back surface of the movable electrode 8 of the movable support portion 9 in the axial direction Y of the vacuum vessel 1 so as to protrude from the movable conductor 6. The movable rod 10 slidably guides and supports the movable support portion 9 in the axial direction Y of the vacuum vessel 1 via a bearing member 11 fixed to the movable conductor 6, with a gap left between the outer peripheral surface of the movable rod 10 and the bearing member 11.

[0006] The convex threaded portion 12b at one end of the operating rod 12 is threadedly engaged with the concave threaded portion 10a on the inner wall at one end of the movable rod 10, and the operating rod head 12a at the other end is connected to a driving source of the vacuum capacitor, such as a motor. In addition, the operating rod 12 is supported by an operating rod support portion 13, which is composed of a threaded receiving portion 13a and a thrust bearing 13b extending from the movable conductor 6 provided to the vacuum container 1 and covering the bearing member 11, so as to be able to rotate freely when receiving the main retraction force F1.

[0007] The operating rod 12 guides and moves the movable rod 10 in the axial direction Y of the vacuum container 1 using the bearing member 11 , and the capacitance of the vacuum capacitor is obtained by the facing area of ​​the fixed electrode 7 and the movable electrode 8 .

[0008] The main bellows 14 has a bellows shape and is made of a thin and flexible metal. The main bellows 14 is configured to allow the movable electrode 8, the movable support 9, and the movable rod 10 to move in the axial direction Y while maintaining the airtightness of the vacuum chamber 15 surrounded by the fixed electrode 7, the movable electrode 8, and the main bellows 14 in the vacuum container 1. One end of the main bellows 14 is connected to the inner wall of the movable conductor 6, and the other end is connected to the movable support 9. An atmospheric chamber 16 having atmospheric pressure is formed on the movable rod 10 side of the main bellows 14 in the vacuum container 1.

[0009] The main bellows 14 has a vacuum pressure F1v that is always pulled in the direction of the vacuum container, and the vacuum pressure F1v is determined by the diameter of the main bellows 14. In addition, within the operating range of 50% extension and 50% contraction based on the initial length of manufacturing, which totals 100%, multiple telescopic operation life is obtained from the allowable stress during telescopic operation, and the telescopic force F1b is set according to the spring constant associated with telescopic operation. The main retraction force F1 is the sum of the vacuum pressure F1v of the main bellows 14, the telescopic force F1b, and the sliding friction force.

[0010] In the above vacuum capacitor, when a driving source such as a motor rotates the operating rod 12 to move the movable rod 10 in the axial direction Y of the vacuum container 1, the intersection area between the fixed electrode 7 and the movable electrode 8 changes, thereby controlling the capacitance to adjust the impedance.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Publication No. 2007-116025

[0014] Patent Document 2: U.S. Patent No. 9805873 Summary of the invention

[0015] In the main retraction force F1 of the main bellows 14 relative to the movable rod 10, the force of the vacuum pressure F1v is constant and large. In addition, the telescopic force F1b changes according to the operation position (capacitance value). Since the main retraction force F1 is large and fluctuates, it is difficult to control and fine-tune the capacitance at high speed.

[0016] The present invention has been proposed in view of such circumstances, and an object of the present invention is to perform high-speed control and fine adjustment of capacitance by reducing the operating force of electrodes that ensure capacitance.

[0017] Therefore, the present invention in one aspect thereof is a vacuum capacitor comprising: a vacuum container accommodating a pair of electrodes capable of ensuring capacitance; and a vacuum expansion container connected in series with the vacuum container, wherein the vacuum container comprises: a movable support portion supporting one of the pair of electrodes; a conductor supporting the movable support portion so as to be capable of reciprocating along the axial direction of the vacuum container; another conductor supporting the other of the pair of electrodes; and a main bellows interposed between the movable support portion and the one conductor, wherein the vacuum expansion container comprises: a movable portion arranged coaxially with the movable support portion; and an adjusting bellows interposed between the movable portion and the inner surface of an end portion of the vacuum expansion container, and wherein the movable support portion and the movable portion are connected by an insulating connecting rod arranged coaxially with the pair of electrodes.

[0018] In the vacuum capacitor according to the aspect of the present invention, an operating lever for operating the movable support portion or the movable portion is provided on the atmosphere side.

[0019] In the vacuum capacitor according to one aspect of the present invention, the adjustment bellows has a vacuum pressure equal to or smaller than a vacuum pressure of the main bellows.

[0020] In the vacuum capacitor according to one aspect of the present invention, the main bellows and the adjustment bellows have the same spring constant and expansion ratio.

[0021] In the vacuum capacitor according to one aspect of the present invention, the main bellows and the adjustment bellows are each set to have an operation range of 50% elongation and 50% contraction with respect to an initial length at the time of manufacture.

[0022] In the vacuum capacitor according to one aspect of the present invention, the other conductor is formed with a through hole through which the insulating connecting rod is inserted and passed, and the vacuum container and the vacuum expansion container are communicated with each other via the through hole.

[0023] According to the present invention, the operating force of the electrode ensuring the capacitance can be reduced, thereby performing high-speed control and fine adjustment of the capacitance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic cross-sectional view of a vacuum capacitor in a first embodiment of the present invention.

[0025] Figure 2 is a schematic cross-sectional view of a conventional vacuum capacitor. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present invention will be explained with reference to the accompanying drawings.

[0027] Figure 1 The vacuum capacitor in the first embodiment as one aspect of the present invention is provided with a vacuum container 1a and a vacuum expansion container 52, the vacuum container 1a accommodates a fixed electrode 7 (another electrode) and a movable electrode 8 (an electrode), the fixed electrode 7 and the movable electrode 8 are a pair of electrodes capable of ensuring capacitance, and the vacuum expansion container 52 is connected in series with the vacuum container 1a.

[0028] The vacuum container 1a is composed of a ceramic tube 2, flange tubes 3 and 4, a fixed conductor 51, and a movable conductor 6 and is sealed.

[0029] The ceramic tube 2 is arranged coaxially with the fixed electrode 7 and the movable electrode 8 in the vacuum container 1 a.

[0030] The flange tube 3 is interposed between one end of the ceramic tube 2 and the fixed conductor 51 (another conductor) on the same axis as above.

[0031] The flange tube 4 is interposed between the other end of the ceramic tube 2 and the movable conductor 6 (one conductor) on the same axis as above.

[0032] The fixed electrode 7 is provided to the fixed conductor 51 inside the vacuum container 1 a , and is composed of a plurality of electrode members having a thin plate substantially cylindrical shape and having different diameters and arranged coaxially at intervals.

[0033] The movable electrode 8 is set on the movable support part 91 and is composed of an electrode component, which can reciprocate along the axial direction Y of the vacuum container 1a. The electrode component has a thin plate roughly cylindrical shape, has different diameters, and is coaxially arranged at a certain interval, so that an arbitrary capacitance can be ensured between the movable electrode 8 and the fixed electrode 7.

[0034] A movable rod 10 that reciprocates in the axial direction Y by an operating rod 12 is provided at the center of the back surface of the movable support portion 91, which is the surface opposite to the surface where the movable electrode 8 is located. The movable rod 10 is surrounded by the main bellows 50 between the movable conductor 6 and the movable support portion 91, and is coaxially supported with the flange pipe 4 by a bearing member 11 in the movable conductor 6.

[0035] The operating rod 12 includes a convex threaded portion 12b on one side that is threadedly engaged in the concave threaded portion 10a of the movable rod 10, and an operating rod head 12a on the other side, which is connected to a driving source of the vacuum capacitor, such as a motor, and is rotatably supported by an operating rod support portion 13 in the movable conductor 6.

[0036] The operating rod support portion 13 is composed of a threaded receiving portion 13a provided to the movable conductor 6 to cover the bearing member 11 on the atmosphere side of the movable conductor 6, and a thrust bearing 13b that reduces the rotation torque of the operating rod 12 at the threaded receiving portion 13a. With this operating rod support portion 13, the operating rod 12 is rotated by a driving source such as a motor, and the movable rod 10 moves in the axial direction Y while being guided by the bearing member 11. Therefore, the facing area of ​​the movable electrode 8 and the fixed electrode 7 becomes variable, so that a desired capacitance can be obtained.

[0037] The main bellows 50 has a bellows shape, is made of a copper alloy or a copper-plated flexible thin metal, and is capable of expansion and contraction in the axial direction Y of the vacuum container 1a. The main bellows 50 is coaxially arranged with the flange tube 4, and one end of the main bellows 50 is connected to the inner wall of the movable conductor 6, and the other end is connected to the movable support portion 91 to surround the movable rod 10, thereby maintaining the vacuum chamber 15 airtightly through the fixed electrode 7 and the movable electrode 8. In addition, an atmospheric chamber 16 in an atmospheric pressure state is formed on the movable rod 10 side of the main bellows 50 in the vacuum container 1a.

[0038] A through hole 51a is formed at the center of the fixed conductor 51, and an insulating connecting rod 55 connected to the movable support part 91 is inserted and passed through the through hole 51a. One end of the insulating connecting rod 55 is fixed to the fixing seat 91a at the center of the movable electrode 8 side of the movable support part 91, and the other end passes through the through hole 51a of the fixed conductor 51 and is fixed to the fixing seat 54a of the movable part 54.

[0039] On the atmosphere side of the fixed conductor 51 , there is provided a vacuum expansion container 52 which has a cylindrical shape with a bottom and whose diameter is smaller than those of the ceramic tube 2 and the flange tubes 3 and 4 .

[0040] The vacuum expansion container 52 is provided with a movable portion 54 connected to an insulating connecting rod 55 introduced by inserting the through hole 51 a of the fixed conductor 51 , and an adjusting bellows 53 interposed between the movable portion 54 and the inner bottom surface of the vacuum expansion container 52 .

[0041] The regulating bellows 53 is interposed between the movable portion 54 and the inner surface of the end portion of the vacuum expansion container 52. Specifically, the regulating bellows 53 is set to have a spring constant that is the same as that of the main bellows 50 and a vacuum pressure that is equal to or less than the vacuum pressure of the main bellows 50, and the vacuum chamber 15a formed by the fixed conductor 51, the movable portion 54 and the regulating bellows 53 is maintained airtightly, and the movable portion 54 and the insulating connecting rod 55 are provided in the vacuum expansion container 52 so as to be movable in the axial direction Y. Inside the regulating bellows 53, an atmospheric chamber 16a in an atmospheric pressure state is formed by the air suction and exhaust holes 52a at the bottom of the vacuum expansion container 52. The regulating retraction force F3 of the regulating bellows 53 is the sum of the vacuum pressure F3v and the expansion and contraction force F3b of the regulating bellows 53.

[0042] As described above, the main bellows 50 , the insulating connecting rod 55 and the regulating bellows 53 are arranged in series along the axial direction Y, and an operating rod (omitted in the figure) is further provided on the atmosphere side of the main bellows 50 or the regulating bellows 53 .

[0043] According to the vacuum capacitor in this embodiment, the operating rod 12 is rotated by a driving source such as a motor in the atmosphere, the movable rod 10 and the movable support portion 91 move in the axial direction Y, the main bellows 50 is extended and contracted, and the facing area between the fixed electrode 7 and the movable electrode 8 changes. Therefore, the capacitance generated by the fixed electrode 7 and the movable electrode 8 can be controlled, and the impedance can be adjusted as desired. In conjunction with this, the insulating connecting rod 55 passes through the through hole 51a of the fixed conductor 51 and causes the adjustment bellows 53 to expand and contract via the movable portion 54 in the vacuum chamber 15a, and the main retraction force F2 and the adjustment retraction force F3 become forces in opposite directions, offsetting each other, so that the total retraction force F4 becomes only sliding friction.

[0044] As described above, the total retraction force F4 is reduced by canceling out the main retraction force F2 of the main bellows 50 and the adjustment retraction force F3 of the adjustment bellows 53. The insulating connecting rod 55 arranged between the main bellows 50 of the vacuum chamber 15 and the adjustment bellows 53 of the vacuum chamber 15a is insulated in a vacuum, reduces the creepage distance, and can be applied as a compressive force with a high allowable stress, thereby reducing the cross section and diameter of the insulating connecting rod 55.

[0045] In addition, since the operating rod 12 is arranged on the side of the atmospheric chamber 16 of the main bellows 50 on the same axis as the main bellows 50, the insulating connecting rod 55 and the adjusting bellows 53, a driving source such as a motor connected to the operating rod 12 can be set in the atmosphere, making maintenance and inspection easier.

[0046] In addition, if the vacuum pressure F3v of the regulating bellows 53 is equal to the vacuum pressure F2v of the main bellows 50, the vacuum pressure F3v and the vacuum pressure F2v cancel each other out, and if the vacuum pressure F3v is equal to or less than the vacuum pressure F2v, a total retraction force F4 is generated corresponding to the vacuum pressure reduction determined based on the conditions of a driving source such as a motor.

[0047] Then, the expansion and contraction force F2b of the main bellows 50 and the expansion and contraction force F3b of the adjustment bellows 53 have the same spring constant and expansion and contraction rate, and the expansion and contraction force F3b of the adjustment bellows 53 becomes a force in the opposite direction to the expansion and contraction force F2b of the main bellows 50. Therefore, by connecting the main bellows 50 and the adjustment bellows 53 via the insulating connecting rod 55, the expansion and contraction forces F2b and F3b cancel each other out, and the total retraction force F4 can be reduced.

[0048] Furthermore, by setting each of the main bellows 50 and the regulating bellows 53 to have an operating range of 50% extension and 50% contraction, totaling 100%, relative to the initial length at the time of manufacture, the expansion and contraction force F2b of the main bellows 50 and the expansion and contraction force F3b of the regulating bellows 53 are the same, and they become forces acting in opposite directions to each other. Therefore, by the above connection, the expansion and contraction forces F2b and F3b cancel each other out, and the total retraction force F4 can be reduced.

[0049] Furthermore, by connecting the vacuum container 1a and the vacuum expansion container 52 via the fixed conductor 51 formed with the through hole 51a through which the insulating connecting rod 55 is inserted, the vacuum chamber 15 of the vacuum container 1a communicates with the vacuum chamber 15a of the vacuum expansion container 52. Therefore, vacuum brazing and vacuum maintenance are combined into a single process, thereby eliminating the need for multiple manufacturing and assembling processes for the sealed container.

[0050] Then, the insulating connecting rod 55 is thinly constructed for bearing pressure, and is introduced into the vacuum expansion container 52 on the same axis as the fixed electrode 7 and the movable electrode 8. Therefore, the insulating connecting rod 55 can be connected to the adjustment bellows 53 in the vacuum expansion container 52 without affecting the facing area (capacitance) of the fixed electrode 7 and the movable electrode 8.

[0051] In addition, since the insulating connecting rod 55 is inserted into and passes through the through hole 51a, the insulating connecting rod 55 is in a non-sliding state, the movable mechanism of the vacuum capacitor can be realized only through the bearing member 11, thereby suppressing the misalignment that occurs in the case of a multi-point sliding guide structure, and core adjustment is no longer required.

[0052] As described above, according to the present embodiment, the total retracting force F4 can be a stable force and can be easily fine-tuned, so that high-speed control can be performed by providing a driving source such as a motor in the atmosphere.

[0053] exist Figure 1 In the first embodiment, the operating rod 12 is arranged on the atmospheric chamber 16 side of the main bellows 50, but it can also be arranged on the atmospheric chamber 16a side of the regulating bellows 53.

Claims

1. A vacuum capacitor, comprising: a vacuum container accommodating a pair of electrodes capable of ensuring capacitance; as well as a vacuum expansion container, the vacuum expansion container being connected in series with the vacuum container, The vacuum container comprises: a movable support portion, the movable support portion supporting one electrode of the pair of electrodes; a conductor supporting the movable support portion so as to be capable of reciprocating movement in the axial direction of the vacuum container; another conductor supporting the other electrode of the pair of electrodes; and a main bellows, the main bellows being interposed between the movable support and the one conductor, The vacuum expansion container comprises: a movable portion disposed coaxially with the movable supporting portion; and an adjusting bellows interposed between the movable portion and an inner surface of an end portion of the vacuum expansion container, and The movable support portion and the movable portion are connected via an insulating connecting rod coaxially arranged with the pair of electrodes. 2 . The vacuum capacitor according to claim 1 , wherein an operating lever for operating the movable support portion or the movable portion is provided on the atmosphere side.

3. The vacuum capacitor according to claim 1 or 2, wherein the adjustment bellows has a vacuum pressure equal to or smaller than a vacuum pressure of the main bellows.

4. The vacuum capacitor according to claim 1 or 2, wherein the main bellows and the adjustment bellows have the same spring constant and expansion ratio.

5. The vacuum capacitor according to claim 1 or 2, wherein the main bellows and the adjusting bellows each have an elongation of 50% and a contraction of 50% relative to an initial length at the time of manufacture.

6. The vacuum capacitor according to claim 1 or 2, wherein the other conductor is formed with a through hole through which the insulating connecting rod is inserted, and The vacuum container and the vacuum expansion container are communicated with each other via the through hole.

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