Vacuum capacitor

Abstract

The application discloses a vacuum capacitor, which comprises an insulating shell, a first electrode group and a second electrode group, the first electrode group and the second electrode group are jointly contained in a vacuum chamber inside the insulating shell and can be coupled with each other through an electric field formed therebetween; a protective cover is arranged between the insulating shell and the first electrode group and / or the second electrode group, the protective cover is used for blocking impurities released from the first electrode group and / or the second electrode group to prevent the impurities from being deposited on the inner wall of the insulating shell; the protective cover is provided with an annular part and a flange part, an air-adsorbing element is fixed on the protective cover, the air-adsorbing element is made of a high-temperature sintering of a multi-element alloy powder on a metal base strip and is annular, and the air-adsorbing element is wrapped on the outer wall and / or the inner wall of the annular part. The application is provided with the protective cover, and the air-adsorbing element is wrapped on the annular part of the protective cover, so that the insulation resistance and the vacuum degree are greatly improved, and the service life of the vacuum capacitor is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of capacitors, in particular to a vacuum capacitor. BACKGROUND

[0002] A vacuum capacitor is a kind of capacitor with ceramic as the insulating shell, vacuum as the medium, and high-conductivity oxygen-free copper as the electrode. Compared with other capacitors, it has the advantages of high withstand voltage, large current carrying capacity, low high-frequency loss, self-healing after transient overload, etc., and is particularly suitable for high-frequency and high-voltage application fields. At present, vacuum capacitors have been widely used in broadcast transmission, medical nuclear magnetic resonance, high-frequency heating, semiconductor etching, plasma cleaning and other equipment. In these high-frequency devices, vacuum capacitors and high-frequency inductors form a resonant circuit to complete high-frequency impedance matching and realize stable transmission of radio frequency power.

[0003] The electrode material of a vacuum capacitor is usually pure copper with impurity content ≤0.03%, and the ceramic material used as the insulating shell is usually 95% Al2O3. Since the vacuum capacitor works in a high-frequency and high-voltage state for a long time, the impurities in the electrode will slowly escape from the crystal lattice and eventually deposit on the inner wall of the ceramic shell, causing further degradation of the insulation performance of the ceramic shell. The insulation resistance of the insulating shell made of Al2O3 material itself can reach 10 8 MΩ or above, but due to the above use process, the insulation resistance of the vacuum capacitor will decrease to the range of 10 3 MΩ to 10 5 MΩ. The decrease in insulation resistance of the insulating shell not only increases the loss of the vacuum capacitor, but also causes the product to heat up during use, especially under high-frequency and high-voltage conditions, the temperature rise rate of the capacitor is further increased, affecting the overall output power and service life of the radio frequency impedance matching device.

[0004] In addition, during the long-term high-frequency and high-voltage operation of the vacuum capacitor, the gas inside the electrode material will also be released. The released gas will cause the vacuum degree of the capacitor to decrease, and thus will also reduce the withstand voltage capability and service life of the vacuum capacitor. At present, although the existing technology can effectively solve the above problems by setting a getter in the vacuum capacitor to adsorb the released gas, the existing getter can only be placed in the middle position of the electrode disc (such as patent publication numbers CN101919014B and CN114121484A) due to the structure of the vacuum capacitor itself. The space is small and cannot accommodate more getters, and the adsorption area is very small. In the long-term high-frequency and high-voltage working environment of the vacuum capacitor, the adsorption capacity is limited, and it is difficult to maintain a high vacuum degree for a long time, which affects the withstand voltage capability and service life of the vacuum capacitor. Therefore, it is necessary to improve the existing technology to overcome the defects in the existing technology. SUMMARY

[0005] The problem to be solved by the present invention is to provide a vacuum capacitor to overcome the defect that the insulation performance of the ceramic shell and the vacuum degree of the existing vacuum capacitor are easily degraded during long-term use, resulting in increased loss of the vacuum capacitor, reduced voltage resistance, and thus shortened service life.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a vacuum capacitor, comprising: an insulating shell, a first electrode group and a second electrode group, the first electrode group and the second electrode group being jointly accommodated in a vacuum chamber inside the insulating shell and capable of coupling with each other through the electric field formed therebetween; a protective cover is provided between the insulating shell and the first electrode group and / or the second electrode group, the protective cover being used to block impurities released from the inside of the material of the first electrode group and / or the second electrode group to prevent them from being deposited on the inner wall of the insulating shell.

[0007] As a further improvement of the present invention, the protective cover is provided with an annular portion distributed around the first electrode group and / or the second electrode group and a flange portion integrally connected to the annular portion, the flange portion is fixedly connected to the insulating shell, and a gap is left between the annular portion and the insulating shell and the first electrode group and / or the second electrode group.

[0008] As a further improvement of the present invention, the first electrode group and the second electrode group are both composed of a plurality of electrode rings arranged concentrically and at intervals, and the electrode rings of the first electrode group and the electrode rings of the second electrode group are alternately and concentrically arranged in the vacuum chamber; the distance between the annular portion and the insulating shell and the distance between the annular portion and the first electrode group and / or the second electrode group are both greater than the distance between the electrode rings of the first electrode group and the electrode rings of the second electrode group.

[0009] As a further improvement of the present invention, two insulating shells are provided, and the two insulating shells are respectively sealed and fixedly connected to both sides of the flange portion;

[0010] Among them, the outer circumferential surface of the flange part is flush with the outer circumferential surface of the insulating shell; or the outer circumferential surface of the flange part is concave inward compared to the outer circumferential surface of the insulating shell; or the flange part protrudes radially outward from the outer circumferential surface of the insulating shell, and the flange part is provided with a mounting hole at the protruding part.

[0011] As a further improvement of the present invention, the insulating housing is provided with a boss along the inner wall, and the flange portion is fixedly connected to the boss;

[0012] Alternatively, the insulating shell is provided with a groove along the inner wall, and the flange portion is fixedly inserted into the groove.

[0013] As a further improvement of the application, the annular part extends towards the axial direction of the vacuum capacitor and beyond the corresponding end face of the insulating shell, and the mouth of the annular part is provided with a chamfered round corner.

[0014] As a further improvement of the application, the protective cover is fixed with a getter element.

[0015] As a further improvement of the application, the getter element is made of a multi-element alloy powder sintered at high temperature on a metal base and in the shape of a ring, which is wrapped around the outer wall and / or the inner wall of the annular part, and the distance between the getter element and the insulating shell and the distance between the getter element and the first electrode group and / or the second electrode group are both greater than the distance between the electrode rings of the first electrode group and the electrode rings of the second electrode group.

[0016] As a further improvement of the application, the vacuum capacitor further comprises a first electrode disc and a second electrode disc, which are respectively fixedly connected to the two ends of the insulating shell, the first electrode group is fixed to the first electrode disc, and the second electrode group is fixed to the second electrode disc.

[0017] As a further improvement of the application, the relative positions of the first electrode group and the second electrode group in the vacuum chamber are adjustable to change the coupling area between the first electrode group and the second electrode group.

[0018] The application provides a vacuum capacitor, which is provided with a protective cover between the insulating shell and the first electrode group and / or the second electrode group. During long-term high-frequency and high-voltage operation, the impurities released by the first electrode group and / or the second electrode group are blocked by the protective cover in advance, so as to prevent the impurities from depositing on the inner wall of the insulating shell, avoid the pollution of the inner wall of the insulating shell, improve the insulation resistance of the insulating shell, and thus reduce the loss value of the vacuum capacitor and improve the service life, meeting the requirements of high frequency, low loss and long service life in the field of semiconductor manufacturing equipment. Meanwhile, the application is provided with a getter element fixed on the protective cover. Since the getter element is wrapped around the annular part of the protective cover, the capacity of the getter element can be greatly improved, and the getter element has a larger adsorption area, which significantly enhances the ability of the getter element to long-term adsorb the gas released from the electrode material. In addition, compared with the arrangement mode of the conventional getter element, the getter element of the application is directly close to the gas release source to form a ring-shaped surrounding adsorption area, which significantly improves the adsorption efficiency and can long-term maintain the vacuum degree inside the vacuum capacitor, further improving the pressure resistance and service life of the vacuum capacitor. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0020] Figure 1 A sectional view of the vacuum capacitor according to Embodiment 1 of the present application;

[0021] Figure 2 A sectional view of the vacuum capacitor according to Embodiment 2 of the present application; Figure 1 An enlarged view of part A in FIG. 5;

[0022] Figure 3 A sectional view of the vacuum capacitor according to Embodiment 2 of the present application;

[0023] Figure 4 A perspective view of the vacuum capacitor according to Embodiment 2 of the present application;

[0024] Figure 5 A sectional view of the vacuum capacitor according to Embodiment 3 of the present application;

[0025] Figure 6 A sectional view of the vacuum capacitor according to Embodiment 4 of the present application;

[0026] Figure 7 A sectional view of the vacuum capacitor according to Embodiment 5 of the present application;

[0027] Figure 8 A sectional view of the vacuum capacitor according to Embodiment 6 of the present application;

[0028] Figure 9 A sectional view of the vacuum capacitor according to Embodiment 7 of the present application.

[0029] The following description is made in conjunction with the drawings:

[0030] 1, insulating housing; 101, vacuum chamber; 102, boss; 103, groove; 2, first electrode group; 3, second electrode group; 4, protective cover; 401, annular portion; 4011, rounded corner; 402, flange portion; 4021, mounting hole; 5, getter element; 6, first electrode disc; 7, second electrode disc; 8, movable electrode disc; 9, fixed electrode disc; 10, end cover; 11, bellows; 12, screw rod; 13, pull rod; 14, sleeve. DETAILED DESCRIPTION

[0031] The present application will be described in detail below in conjunction with the drawings and specific embodiments.

[0032] Following, the embodiments of the present application are described through specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in the specification without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] It should be noted that the various aspects of the embodiments described below are within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms and that any specific structure and / or function described herein is merely illustrative. Based on the teachings herein one skilled in the art should appreciate that an aspect described herein can be implemented independently of any other aspects and that an aspect can be implemented both as any number of software and / or hardware structures and as any number of combinations of software and / or hardware structures. For example, an apparatus can be implemented using any number and combination of the aspects described herein.

[0034] It should also be noted that the figures provided in the following embodiments are only schematically illustrating the basic concepts of the present application, and only the components related to the present application are shown in the figures, not drawn according to the number, shape and size of the components in actual implementation, and the shape, number and proportion of each component in actual implementation can be arbitrarily changed, and the layout pattern of the components can also be more complex.

[0035] In addition, in the following description, specific details are provided in order to facilitate a thorough understanding of the examples. However, one skilled in the art will understand that the examples can be practiced without these specific details.

[0036] The technical solutions provided by the embodiments of the present application are described below in combination with the drawings.

[0037] Embodiment one

[0038] Referring to Figure 1 The present application provides a vacuum capacitor, comprising: an insulating shell 1, a first electrode group 2, a second electrode group 3, a first electrode disc 6 and a second electrode disc 7.

[0039] Exemplarily, the insulating shell 1 is a cylinder with both ends open, the first electrode disc 6 and the second electrode disc 7 are both discs with connecting rings, the first electrode disc 6 and the second electrode disc 7 are respectively fixedly connected to the two ends of the insulating shell 1 through the connecting rings on them in a sealed manner, and the fixing manner can adopt but is not limited to brazing; meanwhile, a vacuum chamber 101 is formed between the insulating shell 1, the first electrode disc 6 and the second electrode disc 7.

[0040] Further, the first electrode group 2 and the second electrode group 3 are jointly accommodated in the vacuum chamber 101 inside the insulating shell 1, and the first electrode group 2 and the second electrode group 3 are respectively fixed on the inner end faces of the first electrode disc 6 and the second electrode disc 7 facing each other.

[0041] Among them, the first electrode group 2 and the second electrode group 3 are both arranged concentrically and spaced by a plurality of electrode rings, and the electrode rings of the first electrode group 2 and the second electrode group 3 are alternately and concentrically arranged in the vacuum chamber 101, so that the first electrode group 2 and the second electrode group 3 can be coupled to each other through the electric field formed therebetween.

[0042] Obviously, the vacuum capacitor described in the embodiment is a fixed vacuum capacitor, that is, the coupling area of the first electrode group 2 and the second electrode group 3 is fixed and does not change, and the capacitance is a constant value. The coupling area described herein refers to the effective area of the first electrode group 2 and the second electrode group 3 that affects and interacts with each other under the action of the electric field, that is, the part of the area that overlaps in the radial direction.

[0043] As one of the important improvements in the present application, the protective cover 4 is arranged between the insulating shell 1 and the first electrode group 2 and / or the second electrode group 3, so that the impurities released by the first electrode group 2 and / or the second electrode group 3 can be blocked by the protective cover 4 in advance during long-term high-frequency high-voltage operation, thereby preventing the impurities from depositing on the inner wall of the insulating shell 1, avoiding the pollution of the inner wall of the insulating shell 1, improving the insulation resistance of the insulating shell 1, thereby being able to reduce the loss value of the vacuum capacitor and improve the service life, meeting the requirements of high frequency, low loss and long life in the field of semiconductor manufacturing equipment.

[0044] It should be noted that the length of the protective cover 4 in the present application and its installation position in the axial direction of the vacuum capacitor are not limited, that is, the length and installation position of the protective cover 4 are reasonably set according to the requirements, so that the protective cover 4 can be between the insulating shell 1 and the first electrode group 2, between the insulating shell 1 and the second electrode group 3, or between the insulating shell 1, the first electrode group 2 and the second electrode group 3.

[0045] Exemplarily, the insulating shell 1 can adopt a ceramic material; the protective cover 4 can adopt a metal material which can withstand high-temperature environment in the production process, and the material of the protective cover 4 in the embodiment is the same as that of the first electrode group 2 and the second electrode group 3, i.e., pure copper with impurity content ≤0.03%.

[0046] Further, the protective cover 4 is provided with an annular portion 401 distributed around the first electrode group 2 and / or the second electrode group 3 and a flange portion 402 integrally connected to the annular portion 401, and the annular portion 401 is coaxially arranged with the insulating shell 1, the first electrode group 2 and the second electrode group 3.

[0047] As shown in Figure 1 , in the embodiment, the flange portion 402 on the protective cover 4 can be formed by folding the lower end of the annular portion 401 outward by 90°, and the flange portion 402 is fixedly connected to the insulating shell 1, while leaving a gap between the annular portion 401 and the insulating shell 1 and the first electrode group 2 and / or the second electrode group 3.

[0048] In the embodiment, the annular portion 401 is located between the upper half of the insulating shell 1 and the first electrode group 2, and the lower end of the annular portion 401 and the upper end of the second electrode group 3 have a radially opposite overlapping portion. Among them, the distance between the annular portion 401 and the insulating shell 1 is L1, the distances between the annular portion 401 and the first electrode group 2 and the second electrode group 3 are L2 and L3 respectively, and the distance between the electrode ring of the first electrode group 2 and the electrode ring of the second electrode group 3 is L0, L1, L2 and L3 are all greater than L0, so as to prevent the withstand voltage of the vacuum capacitor from being affected by the protective cover 4 and thus being reduced.

[0049] Continuing to refer to Figure 1 , the insulating shell 1 in the embodiment is provided with two, and the two insulating shells 1 are respectively sealingly and fixedly connected to the two sides of the flange portion 402. The fixing mode between the flange portion 402 and the insulating shell 1 can adopt but is not limited to brazing, resistance welding, laser welding, etc. Among them, the two insulating shells 1 can be of the same length or one long and one short, and the present application does not make any limitation in this regard.

[0050] As an option, the outer periphery of the flange portion 402 is flush with the outer periphery of the insulating shell 1 (as shown in Figure 1 ), or the outer periphery of the flange portion 402 is recessed inward compared with the outer periphery of the insulating shell 1, or the flange portion 402 protrudes outward along the radial direction beyond the outer periphery of the insulating shell 1.

[0051] As preferred, the upper port of the annular part 401 extends towards the axial direction of the vacuum capacitor and beyond the corresponding end face of the insulating shell 1, which can provide better impurity blocking effect and avoid the influence of the uneven electric field caused by uneven solder flow and misalignment of parts on the capacitor carrying voltage. At the same time, the upper port of the annular part 401 does not contact the first electrode disc 6, and the distance between the annular part 401 and the first electrode disc 6 also needs to be greater than the distance between the electrode rings of the first electrode group 2 and the electrode rings of the second electrode group 3, for preventing the withstand voltage of the vacuum capacitor from being affected by the protective cover.

[0052] Referring to Figure 2 , the upper port of the annular part 401 is in an outwardly curved shape, and the port of the annular part 401 is provided with a chamfered corner 4011, which prevents the protective cover 4 from discharging with the first electrode disc 6 under alternating electric field, causing unstable working voltage of the capacitor.

[0053] During the long-term high-frequency and high-voltage working process of the vacuum capacitor, the gas inside the materials of the first electrode group 2 and the second electrode group 3 will also be released, and the released gas will cause the vacuum degree of the capacitor to decrease, thereby also reducing the withstand voltage capability and service life of the vacuum capacitor.

[0054] To this end, the present application fixes the getter element 5 on the protective cover 4, and uses the getter element 5 to absorb the gas released inside the electrode material, so as to maintain the internal vacuum degree of the vacuum capacitor, thereby improving the withstand voltage capability and service life of the vacuum capacitor.

[0055] The getter element 5 is made of multi-element alloy powder sintered on a metal base at high temperature, and belongs to a high-density non-evaporable getter. The getter has the characteristics of absorbing gas for a long time at room temperature after high-temperature activation, and the manufacturing process belongs to the prior art. The getter element 5 prepared is in a ring structure, which is wrapped on the outer wall and / or inner wall of the annular part 401.

[0056] Compared with the arrangement mode of the traditional getter element, the present application sets the getter element in a ring shape and wraps it on the annular part of the protective cover, so that the capacity of the getter element can be greatly improved, and has a larger adsorption area, which significantly enhances the ability of the getter element to absorb the gas released inside the electrode material for a long time. In addition, the getter element of the present application is directly close to the gas release source, forming a ring-shaped adsorption area, and the adsorption efficiency is significantly improved, which can maintain the internal vacuum degree of the vacuum capacitor for a long time, and further improve the withstand voltage capability and service life of the vacuum capacitor.

[0057] When the getter element 5 is fixed to the outer wall of the annular portion 401, the spacing between the getter element 5 and the insulating shell 1 should be greater than the spacing between the electrode rings of the first electrode group 2 and the electrode rings of the second electrode group 3; when the getter element 5 is fixed to the inner wall of the annular portion 401, the spacing between the getter element 5 and the first electrode group 2 and the second electrode group 3 should be greater than the spacing between the electrode rings of the first electrode group 2 and the electrode rings of the second electrode group 3, preventing the withstand voltage of the vacuum capacitor from being affected by the getter element 5 and thus decreasing.

[0058] In order to facilitate production, the embodiment is specifically to fix the getter element 5 to the outer wall of the annular portion 401, and the fixing mode can adopt but is not limited to resistance welding or laser welding and the like.

[0059] In order to verify the technical effects brought by the application, the vacuum capacitor of the application and the conventional vacuum capacitor of the same specification but without the protective cover 4 and the getter element 5 are tested for their vacuum degree and insulation resistance during working, and the test results are as follows:

[0060] Table 1

[0061] Product No. Capacitance (pF) Vacuum degree (Pa) Insulation resistance (MΩ) Conventional vacuum capacitor 252 5.02E-04 2.4E+06 Vacuum capacitor of the present invention 220.1 1.98E-04 1.0E+08

[0062] In the table, the capacitance difference between the vacuum capacitor of the application and the conventional vacuum capacitor is due to: in the same specification product, in order to add the protective cover 4, the electrode ring at the outermost side in the vacuum capacitor needs to be removed to provide space for the installation of the protective cover 4, and the reduction of the electrode ring directly causes the capacitance of the vacuum capacitor of the application to be less than that of the conventional vacuum capacitor, but such capacitance difference does not have obvious influence on the test results of the vacuum degree and the insulation resistance.

[0063] As can be seen from the above table, by arranging the protective cover 4 and wrapping the getter element 5 on the annular portion 401 of the protective cover 4, the insulation resistance and the vacuum degree of the insulating shell 1 are greatly improved, thereby improving the service life of the vacuum capacitor.

[0064] Embodiment Two

[0065] Referring to Figure 3 and Figure 4 The difference between the embodiment and the embodiment one is that the flange portion 402 of the protective cover 4 protrudes outward along the radial direction beyond the outer circumferential surface of the insulating shell 1, and the flange portion 402 is provided with a mounting hole 4021 at the protruding portion. The mounting hole 4021 can be a through hole or a threaded hole, and the user can ground the protective cover 4 according to the need, further preventing the protective cover 4 from being affected by the surrounding alternating electric field and thus causing the vacuum capacitor to work unstably.

[0066] Embodiment Three

[0067] Referring toFigure 5 This embodiment differs from the first embodiment in that the annular portion 401 of the protective cover 4 is longer than the insulating housing 1, and the upper and lower ends of the annular portion 401 extend axially toward the vacuum capacitor and extend beyond the upper and lower end surfaces of the insulating housing 1, respectively. The flange portion 402 is integrally connected to the center of the outer circumference of the annular portion 401. As a result, the protective cover 4 completely covers the inner wall of the insulating housing 1, providing a more comprehensive barrier to impurities.

[0068] In this embodiment, the upper and lower ports of the annular portion 401 are both bent outward, and at the same time, the upper and lower ports of the annular portion 401 are both configured as rounded corners 4011 formed by chamfering to prevent the protective cover 4 from discharging with the first electrode disk 6 under an alternating electric field, thereby causing unstable working voltage of the capacitor.

[0069] Example 4

[0070] See Figure 6 This embodiment differs from the third embodiment in that the flange portion 402 of the protective cover 4 radially protrudes outward from the outer circumference of the insulating housing 1, and a mounting hole 4021 is provided in the protruding portion of the flange portion 402. The mounting hole 4021 can be a through hole or a threaded hole, allowing the user to ground the protective cover 4 as needed, further preventing the protective cover 4 from being affected by the surrounding alternating electric field and causing unstable operation of the vacuum capacitor.

[0071] Example 5

[0072] See Figure 7 This embodiment differs from the first embodiment in that only one insulating housing 1 is provided, an annular boss 102 is provided along the inner wall of the central portion of the insulating housing 1, and the flange portion 402 is fixedly connected to the boss 102. The fixing method between the flange portion 402 and the boss 102 may be, but is not limited to, brazing, resistance welding, laser welding, or the like.

[0073] Compared with the first embodiment, the protective cover 4 and the insulating housing 1 in this embodiment adopt this assembly structure to increase the creepage distance of the outer surface of the insulating housing 1, and prevent the exposed protective cover 4 from being affected by the environment and causing the insulation performance of the insulating housing 1 to deteriorate.

[0074] Example 6

[0075] See Figure 8 This embodiment differs from the first embodiment in that only one insulating housing 1 is provided, and an annular groove 103 is provided along the inner wall of the central portion of the insulating housing 1. The groove 103 does not penetrate the outer wall of the insulating housing 1, and the flange portion 402 is fixedly connected to the groove 103. The fixing method between the flange portion 402 and the groove 103 can be, but is not limited to, brazing, resistance welding, laser welding, etc.

[0076] Compared with the first embodiment, the protective cover 4 and the insulating shell 1 in the present embodiment adopt the assembly structure, which can increase the creepage distance of the outer surface of the insulating shell 1, and avoid the insulation performance of the insulating shell 1 from being reduced due to the environmental influence on the exposed protective cover 4.

[0077] Seventh embodiment

[0078] The difference between the present embodiment and any one of the first to sixth embodiments is that, in the present embodiment, the vacuum capacitor is a variable vacuum capacitor, i.e., the relative position of the first electrode group 2 and the second electrode group 3 in the vacuum chamber 101 is adjustable, so as to change the coupling area between the first electrode group 2 and the second electrode group 3, and thus the capacitance can be adjusted.

[0079] Specifically, referring to Figure 9 , the vacuum capacitor comprises the insulating shell 1, the first electrode group 2, the second electrode group 3, the movable electrode disc 8, the fixed electrode disc 9, the end cover 10, the bellows 11, a transmission mechanism, and the protective cover 4 and the getter element 5 described in any one of the first to sixth embodiments.

[0080] The end cover 10 and the fixed electrode disc 9 are respectively sealingly welded at the two ends of the insulating shell 1, the movable electrode disc 8 is located in the cavity enclosed by the end cover 10, the fixed electrode disc 9 and the insulating shell 1, and the movable electrode disc 8 is sealingly connected to the end cover 10 through the bellows 11, so as to form the vacuum chamber 101 between the insulating shell 1, the end cover 10, the bellows 11, the movable electrode disc 8 and the fixed electrode disc 9. The first electrode group 2 and the second electrode group 3 are collectively accommodated in the vacuum chamber 101, and the first electrode group 2 and the second electrode group 3 are respectively fixed to the inner end faces of the movable electrode disc 8 and the fixed electrode disc 9 facing each other.

[0081] The transmission mechanism comprises a screw rod 12 and a pull rod 13, a sleeve 14 is fixed on the end cover 10, the screw rod 12 is rotatably installed on the sleeve 14 through a bearing, and the axial movement of the screw rod 12 is limited, i.e., the screw rod 12 can only make rotational movement. The pull rod 13 is high-temperature welded at the middle part of the movable electrode disc 8, the upper end thereof passes through the bellows 11 and is provided with a threaded hole, and the screw rod 12 is threadedly connected to the threaded hole of the pull rod 13.

[0082] When the motor drives the screw rod 12 to rotate, the screw rod 12 will drive the pull rod 13 to move up and down along the axial direction, and synchronously drive the movable electrode disc 8 and the first electrode group 2 to move, so as to change the coupling area between the first electrode group 2 and the second electrode group 3, thereby realizing the adjustment of the capacitance of the high-voltage vacuum capacitor.

[0083] The structure and assembly mode of the protective cover 4 and the getter element 5 can adopt any one of the first to sixth embodiments, which will not be repeated here.

[0084] It can be seen that the vacuum capacitor provided by the application can prevent the impurities released by the first electrode group 2 and / or the second electrode group 3 from depositing on the inner wall of the insulating shell 1 and avoid the inner wall of the insulating shell 1 from being contaminated by arranging the protective cover 4 between the insulating shell 1 and the first electrode group 2 and / or the second electrode group 3, thereby improving the insulation resistance of the insulating shell 1, reducing the loss value of the vacuum capacitor, and prolonging the service life, so as to meet the requirements of high frequency, low loss and long service life in the field of semiconductor manufacturing equipment. Meanwhile, compared with the arrangement mode of the conventional getter element, the getter element 5 is arranged in a ring shape and wrapped on the annular part 401 of the protective cover 4, so that the capacity of the getter element 5 can be greatly improved and the adsorption area is larger, the ability of the getter element 5 to long-term adsorb the gas released from the electrode material is significantly enhanced, in addition, the getter element 5 is directly close to the gas release source to form a ring-shaped adsorption area, the adsorption efficiency is significantly improved, the internal vacuum degree of the vacuum capacitor can be maintained for a long time, and the pressure resistance and service life of the vacuum capacitor are further improved.

[0085] The same or similar parts among the various embodiments in the specification can be referred to each other, and each embodiment focuses on the difference from other embodiments.

[0086] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A vacuum capacitor comprising an insulating housing (1), a first electrode group (2) and a second electrode group (3), wherein the first electrode group (2) and the second electrode group (3) are accommodated together in a vacuum chamber (101) inside the insulating housing (1) and can be coupled to each other through an electric field formed therebetween; characterized in that: A protective cover (4) is provided between the insulating shell (1) and the first electrode group (2) and / or the second electrode group (3), and the protective cover (4) is used to block impurities released from the inside of the material of the first electrode group (2) and / or the second electrode group (3) to prevent them from being deposited on the inner wall of the insulating shell (1); the protective cover (4) is provided with an annular portion (401) distributed around the first electrode group (2) and / or the second electrode group (3) and a flange portion (402) integrally connected to the annular portion (401), and the flange portion (402) is provided with a plurality of protruding ... 2) being fixedly connected to the insulating shell (1), while leaving gaps between the annular portion (401) and the insulating shell (1) and the first electrode group (2) and / or the second electrode group (3); the annular portion (401) extending in the axial direction of the vacuum capacitor and exceeding the corresponding end face of the insulating shell (1); an air intake element (5) being fixed on the protective cover (4); the air intake element (5) being made of multi-element alloy powder sintered at high temperature on a metal base strip and being annular, and being wrapped around the outer wall and / or inner wall of the annular portion (401).

2. The vacuum capacitor according to claim 1, wherein: The first electrode group (2) and the second electrode group (3) are both formed by a plurality of electrode rings arranged concentrically and at intervals, and the electrode rings of the first electrode group (2) and the electrode rings of the second electrode group (3) are alternately and concentrically arranged in the vacuum chamber (101); the spacing between the annular portion (401) and the insulating shell (1) and the spacing between the annular portion (401) and the first electrode group (2) and / or the second electrode group (3) are both greater than the spacing between the electrode rings of the first electrode group (2) and the electrode rings of the second electrode group (3).

3. The vacuum capacitor according to claim 1, wherein: Two insulating shells (1) are provided, and the two insulating shells (1) are respectively sealed and fixedly connected to both sides of the flange portion (402); The outer peripheral surface of the flange portion (402) is flush with the outer peripheral surface of the insulating shell (1); or the outer peripheral surface of the flange portion (402) is in an inwardly concave shape compared to the outer peripheral surface of the insulating shell (1); or the flange portion (402) protrudes radially outward from the outer peripheral surface of the insulating shell (1), and a mounting hole (4021) is provided at the protruding portion of the flange portion (402).

4. The vacuum capacitor according to claim 1, wherein: The insulating housing (1) is provided with a boss (102) along the inner wall, and the flange portion (402) is fixedly connected to the boss (102); Alternatively, the insulating housing (1) is provided with a groove (103) along the inner wall, and the flange portion (402) is fixedly inserted into the groove (103).

5. The vacuum capacitor according to claim 1, wherein: The mouth of the annular portion (401) is configured as a rounded corner (4011) formed by chamfering.

6. The vacuum capacitor according to claim 1, wherein: The distance between the air-intake element (5) and the insulating shell (1), and the distance between the air-intake element (5) and the first electrode group (2) and / or the second electrode group (3) are both greater than the distance between the electrode rings of the first electrode group (2) and the electrode rings of the second electrode group (3).

7. The vacuum capacitor according to claim 1, wherein: The insulating housing (1) further comprises a first electrode disk (6) and a second electrode disk (7), wherein the first electrode disk (6) and the second electrode disk (7) are respectively sealed and fixedly connected to the two ends of the insulating housing (1); the first electrode group (2) is fixed to the first electrode disk (6); and the second electrode group (3) is fixed to the second electrode disk (7).

8. The vacuum capacitor according to claim 1, wherein: The relative positions of the first electrode group (2) and the second electrode group (3) in the vacuum chamber (101) are adjustable to change the coupling area between the first electrode group (2) and the second electrode group (3).

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