vacuum capacitors

Abstract

The vacuum capacitor comprises a vacuum vessel 1a, which houses a fixed electrode 7 and a movable electrode 8, ensuring capacitance, and a vacuum expansion vessel 52, which is connected in series with the vacuum vessel 1a. The vacuum vessel 1a includes a movable support 91 that supports the movable electrode 8, a movable conductor 6 that supports the movable support 91 for reciprocating motion in the axial direction of the vacuum vessel 1a, a fixed conductor 51 that supports the fixed electrode 7, and a main bellows 50 interposed between the movable support 91 and the movable conductor 6. The vacuum expansion vessel 52 includes a movable portion 54 coaxially arranged with the movable support 91 and an adjustment bellows 53 interposed between the movable portion 54 and the inner end surface of the vacuum expansion vessel 52. The movable support 91 and the movable portion 54 are connected by an insulating connecting rod 55 coaxially arranged with the fixed electrode 7 and the movable electrode 8.

Description

Technical Field

[0001] The present invention relates to a vacuum capacitor used 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] Vacuum capacitors have traditionally been used for impedance adjustment in high-frequency devices, such as high-power transmission circuits and high-frequency power supplies in typical semiconductor equipment. Recently, the operating speeds of devices associated with high-frequency devices have increased, and to support these high-speed operations, there is a growing demand for vacuum capacitors with reduced operating forces.

[0003] Figure 2 This 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 multiple thin cylindrical electrode members of varying diameters, arranged at regular intervals on the same axis. This fixed electrode 7 is positioned inside the vacuum vessel 1, where the conductor 5 is fixed. Similar to the fixed electrode 7, the movable electrode 8 is composed of multiple thin cylindrical electrode members of varying diameters, arranged at regular intervals on the same axis. Each electrode member of the movable electrode 8 is inserted and removed while intersecting with the electrode members of the fixed electrode 7, maintaining a slight gap with the fixed electrode 7 to achieve capacitance. The movable electrode 8 is mounted on a movable support 9 made of copper. This movable support 9 can be adjusted in the axial direction Y of the vacuum vessel 1 to allow for insertion and removal relative to the fixed electrode 7.

[0005] A hollow movable rod 10 is provided extending 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] A male threaded portion 12b at one end of operating rod 12 is threadedly engaged with a female threaded portion 10a on the inner wall at one end of movable rod 10. Operating rod head 12a at the other end is connected to a drive source for the vacuum capacitor, such as a motor. Furthermore, operating rod 12 is supported by operating rod support 13, which consists of a threaded receiving portion 13a extending from movable conductor 6 provided on vacuum vessel 1 and covering bearing member 11, and a thrust bearing 13b, so that it can freely rotate when receiving primary 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, flexible metal. The main bellows 14 is configured to allow the movable electrode 8, movable support 9, and movable rod 10 to move in the axial direction Y while maintaining the airtightness of the vacuum chamber 15 defined by the fixed electrode 7, movable electrode 8, and main bellows 14 within the vacuum vessel 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, which is at atmospheric pressure, is formed on the movable rod 10 side of the main bellows 14 within the vacuum vessel 1.

[0009] The main bellows 14 has a vacuum pressure F1v that constantly pulls it in the direction of the vacuum container. This vacuum pressure F1v is determined by the diameter of the main bellows 14. Furthermore, within an operating range of 50% extension and 50% contraction (a total of 100%) based on the initial manufacturing length, the expansion and contraction force F1b is set based on the allowable stress during expansion and contraction, and the spring constant associated with expansion and contraction is used to determine the lifetime of multiple expansion and contraction operations. The main retraction force F1 is the sum of the vacuum pressure F1v of the main bellows 14, the expansion and contraction force F1b, and the sliding friction.

[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 Laid-Open No. 2007-116025

[0014] Patent Document 2: U.S. Patent No. 9,805,873 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. Furthermore, the expansion and contraction force F1b varies depending on the operating position (capacitance value). Because the main retraction force F1 is large and fluctuates, high-speed control and fine-tuning of the capacitance are difficult.

[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 in 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 coaxially arranged with the movable support portion; and an adjustment 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 coaxially arranged 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 / contraction 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 operating 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 the vacuum vessel and the vacuum expansion vessel communicate with each other via the through hole.

[0023] According to the present invention, the operating force of electrodes ensuring capacitance can be reduced, thereby performing high-speed control and fine adjustment of 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 (one electrode). The fixed electrode 7 and the movable electrode 8 are a pair of electrodes capable of ensuring capacitance. The vacuum expansion container 52 is connected in series with the vacuum container 1a.

[0028] The vacuum container 1 a 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 coaxially arranged 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 (the other 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 coaxially arranged 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 is provided at the center of the rear surface of the movable support portion 91, which is the surface opposite to the surface on which the movable electrode 8 is located. The movable rod 10 is reciprocated in the axial direction Y by an operating rod 12. The rear surface is surrounded by the main bellows 50 interposed 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 with 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] Operating rod support 13 consists of a threaded receiving portion 13a, which is attached to movable conductor 6 so as to cover bearing member 11 on the atmospheric side of movable conductor 6, and a thrust bearing 13b, which reduces the rotational torque of operating rod 12 at threaded receiving portion 13a. Using this operating rod support 13, operating rod 12 is rotated by a drive source such as a motor, and movable rod 10 moves in axial direction Y while being guided by bearing member 11. Consequently, the facing area between movable electrode 8 and fixed electrode 7 becomes variable, enabling the desired capacitance to be achieved.

[0037] The main bellows 50 has a bellows shape and is made of a thin, flexible metal such as a copper alloy or copper-plated metal. It is capable of expansion and contraction in the axial direction Y of the vacuum vessel 1a. The main bellows 50 is coaxially arranged with the flange tube 4. 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 91. This surrounds the movable rod 10, thereby maintaining the vacuum chamber 15 airtightly via the fixed electrode 7 and the movable electrode 8. Furthermore, an atmospheric chamber 16, maintained at atmospheric pressure, is formed on the movable rod 10 side of the main bellows 50 in the vacuum vessel 1a.

[0038] A through hole 51a is formed in the center of the fixed conductor 51, through which an insulating connecting rod 55 connected to the movable support portion 91 is inserted. One end of the insulating connecting rod 55 is fixed to a fixing seat 91a in the center of the movable support portion 91 on the side of the movable electrode 8, 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 portion 54.

[0039] On the atmosphere side of the fixed conductor 51 , a vacuum expansion container 52 is provided which has a cylindrical shape with a bottom and has a diameter 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 inserted into 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 vessel 52. Specifically, the regulating bellows 53 is configured to have a spring constant equal to that of the main bellows 50 and a vacuum pressure equal to or less than that of the main bellows 50. The vacuum chamber 15a formed by the fixed conductor 51, the movable portion 54, and the regulating bellows 53 is airtightly maintained. The movable portion 54 and the insulating connecting rod 55 are positioned within the vacuum expansion vessel 52 so as to be movable in the axial direction Y. Within the regulating bellows 53, an atmospheric chamber 16a at atmospheric pressure is formed by the intake and exhaust holes 52a at the bottom of the vacuum expansion vessel 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 of this embodiment, the operating rod 12 is rotated by a driving source such as a motor in the atmosphere, causing the movable rod 10 and movable support portion 91 to move in the axial direction Y, thereby expanding and contracting the main bellows 50 and changing the facing area between the fixed electrode 7 and the movable electrode 8. This allows the capacitance generated by the fixed electrode 7 and the movable electrode 8 to be controlled, and the impedance to 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, via the movable portion 54 in the vacuum chamber 15a, causes the adjustment bellows 53 to expand and contract. The main retraction force F2 and the adjustment retraction force F3 act in opposite directions, canceling each other out, resulting in a total retraction force F4 consisting solely of sliding friction.

[0044] As described above, the main retraction force F2 of the main bellows 50 and the regulating retraction force F3 of the regulating bellows 53 cancel each other out, reducing the total retraction force F4. The insulating connecting rod 55, disposed between the main bellows 50 of the vacuum chamber 15 and the regulating bellows 53 of the vacuum chamber 15a, is insulated in a vacuum, reducing the creepage distance and enabling the application of 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, the 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 the 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 relative to their initial lengths at the time of manufacture, for a total of 100%, the expansion and contraction force F2b of the main bellows 50 and the expansion and contraction force F3b of the regulating bellows 53 become identical, acting in opposite directions. Consequently, through this connection, the expansion and contraction forces F2b and F3b cancel each other out, reducing the total retraction force F4.

[0049] Furthermore, by connecting the vacuum container 1a and the vacuum expansion container 52 via a fixed conductor 51 formed with a through-hole 51a through which an 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. Thus, vacuum brazing and vacuum maintenance are combined into a single process, eliminating the need for multiple manufacturing and assembly processes for the sealed container.

[0050] Then, the insulating connecting rod 55 is thinly constructed to withstand pressure and is introduced into the vacuum expansion vessel 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 vessel 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 by 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 retraction 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 provided on the atmospheric chamber 16 side of the main bellows 50 , but may be provided on the atmospheric chamber 16 a 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 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, said main bellows being interposed between said movable support portion and said 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 wherein the movable support portion and the movable portion are connected via an insulating connecting rod coaxially arranged with the pair of electrodes, wherein the other conductor is formed with a through hole, the insulating connecting rod is inserted through the through hole, and The vacuum container and the vacuum expansion container are communicated with each other via the through hole. 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 , 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 , wherein the main bellows and the adjustment bellows have the same spring constant and expansion ratio. 5 . The vacuum capacitor according to claim 1 , wherein the main bellows and the adjustment bellows each have an elongation of 50% and a contraction of 50% relative to an initial length at the time of manufacture.

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