Vacuum capacitor

Abstract

The invention discloses a vacuum capacitor, which comprises an insulating shell, a first electrode group and a second electrode group, and is characterized in that the first electrode group and the second electrode group are jointly accommodated in a vacuum cavity in the insulating shell and can be mutually coupled through an electric field formed between the first electrode group and the second electrode group; 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 interior of the first electrode group and / or the second electrode group so as 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 suction element is fixed to the protective cover, and the air suction element is made of multi-element alloy powder through high-temperature sintering on a metal base band, is annular and wraps the outer wall and / or the inner wall of the annular part. According to the vacuum capacitor, the protection cover is arranged, and the air suction element is wrapped on the annular part of the protection cover, so that the insulation resistance and the vacuum degree are greatly improved, and the service life of the vacuum capacitor is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitors, and in particular to a vacuum capacitor. Background Art

[0002] A vacuum capacitor is a capacitor with a ceramic insulating shell, a vacuum dielectric, and electrodes made of high-conductivity oxygen-free copper. Compared to other capacitors, it offers advantages such as high voltage resistance, high current carrying capacity, low high-frequency losses, and self-healing after transient overloads, making it particularly suitable for high-frequency and high-voltage applications. Currently, vacuum capacitors are widely used in equipment such as broadcast transmission, medical MRI, high-frequency heating, semiconductor etching, and plasma cleaning. In these high-frequency devices, vacuum capacitors form resonant circuits with high-frequency inductors, achieving high-frequency impedance matching and enabling stable transmission of RF power.

[0003] The electrode material of vacuum capacitors is usually pure copper with an impurity content of ≤0.03%, while the ceramic material used as the insulating shell is usually 95% Al2O3. Because vacuum capacitors work under high frequency and high voltage for a long time, the electrodes are affected by high-power alternating electric fields, and the impurities inside them will slowly escape from the lattice and eventually deposit on the inner wall of the ceramic shell, causing the insulation performance of the ceramic shell to further deteriorate. The insulation resistance of the insulating shell made of Al2O3 can reach 10 8 However, due to the above-mentioned use process, the insulation resistance of the vacuum capacitor will drop to 10 3 MΩ~10 5 A decrease in the insulation resistance of the insulating shell will not only increase the loss of the vacuum capacitor, but also cause the product to heat up during use. Especially under high-frequency and high-voltage conditions, the temperature rise rate of the capacitor will further increase, affecting the overall output power and service life of the RF impedance matcher.

[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, which will also reduce the voltage resistance and service life of the vacuum capacitor. At present, although the existing technology can effectively solve the above problems by setting a getter inside the vacuum capacitor and using the getter to absorb the released gas; however, due to the structure of the vacuum capacitor itself, the existing getter can generally only be placed in the middle position of the electrode disk (such as patent publication numbers CN101919014B and CN114121484A). The space is small and cannot accommodate more getters. The adsorption area is very small. Under the long-term high-frequency and high-voltage working environment of the vacuum capacitor, the adsorption capacity is limited, and a high vacuum degree cannot be maintained for a long time, affecting the voltage resistance 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 of the Invention

[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; 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.

[0010] 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; Alternatively, the insulating shell is provided with a groove along the inner wall, and the flange portion is fixedly inserted into the groove.

[0011] As a further improvement of the present invention, the annular portion extends toward the axial direction of the vacuum capacitor and exceeds the corresponding end surface of the insulating shell, and the mouth of the annular portion is configured as a rounded corner formed by chamfering.

[0012] As a further improvement of the present invention, an air suction element is fixed on the protective cover.

[0013] As a further improvement of the present invention, the air-intake element is made of multi-element alloy powder sintered at high temperature on a metal base tape and is ring-shaped. It is wrapped around the outer wall and / or inner wall of the ring-shaped portion, and the distance between the air-intake element and the insulating shell and the distance between the air-intake element and the first electrode group and / or the second electrode group are both greater than the distance between the electrode ring of the first electrode group and the electrode ring of the second electrode group.

[0014] As a further improvement of the present invention, the vacuum capacitor also includes a first electrode disk and a second electrode disk, the first electrode disk and the second electrode disk are respectively sealed and fixedly connected to the two ends of the insulating shell, the first electrode group is fixed to the first electrode disk, and the second electrode group is fixed to the second electrode disk.

[0015] As a further improvement of the present invention, 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.

[0016] The beneficial effects of the present invention are as follows: the present invention provides a vacuum capacitor, which, by providing 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, impurities released by the first electrode group and / or the second electrode group will be blocked in advance by the protective cover, thereby preventing the impurities from being deposited on the inner wall of the insulating shell, avoiding contamination of the inner wall of the insulating shell, and improving the insulation resistance of the insulating shell, thereby reducing the loss value of the vacuum capacitor and increasing the service life, meeting the requirements of high frequency, low loss and long life in the field of semiconductor manufacturing equipment; at the same time, the present invention fixes an air-absorbing element on the protective cover. Since the air-absorbing element is wrapped around the annular portion of the protective cover, the capacity of the air-absorbing element can be greatly increased, and the air-absorbing element has a larger adsorption area, which significantly enhances the ability of the air-absorbing element to long-term adsorb gas released from the electrode material. In addition, compared with the arrangement of traditional air-absorbing elements, the air-absorbing element of the present application is directly close to the gas release source, forming an annular enclosed adsorption area, which significantly improves the adsorption efficiency, can maintain the vacuum degree inside the vacuum capacitor for a long time, and further improves the pressure resistance and service life of the vacuum capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 is a cross-sectional view of a first embodiment of a vacuum capacitor according to the present invention; Figure 2 The vacuum capacitor of the present invention Figure 1 Enlarged view of part A in the middle; Figure 3 is a cross-sectional view of a second embodiment of a vacuum capacitor according to the present invention; Figure 4 A perspective view of a second embodiment of a vacuum capacitor according to the present invention; Figure 5 A cross-sectional view of a third embodiment of a vacuum capacitor according to the present invention; Figure 6 is a cross-sectional view of a fourth embodiment of a vacuum capacitor according to the present invention; Figure 7 A cross-sectional view of a fifth embodiment of a vacuum capacitor according to the present invention; Figure 8 is a cross-sectional view of a sixth embodiment of a vacuum capacitor according to the present invention; Figure 9 This is a cross-sectional view of Example 7 of the vacuum capacitor of the present invention.

[0019] The following description is made with reference to the accompanying drawings: 1. Insulating shell; 101. Vacuum chamber; 102. Boss; 103. Groove; 2. First electrode group; 3. Second electrode group; 4. Protective cover; 401. Ring portion; 4011. Fillet; 402. Flange portion; 4021. Mounting hole; 5. Air suction element; 6. First electrode disk; 7. Second electrode disk; 8. Moving electrode disk; 9. Fixed electrode disk; 10. End cover; 11. Bellows; 12. Screw; 13. Pull rod; 14. Sleeve. DETAILED DESCRIPTION

[0020] The present application is described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0022] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0023] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0024] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples, however, one skilled in the art will appreciate that the examples can be practiced without these specific details.

[0025] The following describes the technical solutions provided by various embodiments of the present application in conjunction with the accompanying drawings.

[0026] Example 1

[0027] See Figure 1 The present invention provides a vacuum capacitor, comprising: an insulating shell 1, a first electrode group 2, a second electrode group 3, a first electrode disk 6 and a second electrode disk 7.

[0028] Exemplarily, the insulating shell 1 is cylindrical with both ends open, and the first electrode disk 6 and the second electrode disk 7 are both disk-shaped with connecting rings. The first electrode disk 6 and the second electrode disk 7 are respectively sealed and fixedly connected to the two ends of the insulating shell 1 through the connecting rings thereon. The fixing method can be but is not limited to brazing; at the same time, a vacuum chamber 101 is formed between the insulating shell 1, the first electrode disk 6 and the second electrode disk 7.

[0029] Furthermore, the first electrode group 2 and the second electrode group 3 are jointly accommodated in the vacuum chamber 101 inside the insulating housing 1 , and the first electrode group 2 and the second electrode group 3 are respectively fixed on the inner end surfaces of the first electrode disk 6 and the second electrode disk 7 facing each other.

[0030] Among them, the first electrode group 2 and the second electrode group 3 are both composed of multiple 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, 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.

[0031] Obviously, the vacuum capacitor described in this embodiment is a fixed vacuum capacitor, meaning that the coupling area between the first electrode group 2 and the second electrode group 3 is fixed, and its capacitance is constant. The coupling area herein refers to the effective area where the first electrode group 2 and the second electrode group 3 interact and influence each other under the action of the electric field, i.e., the radially overlapping area of ​​the first electrode group 2 and the second electrode group 3.

[0032] As one of the important improvements in the present application, a protective cover 4 is provided between the insulating shell 1 and the first electrode group 2 and / or the second electrode group 3. In this way, during long-term high-frequency and high-voltage operation, impurities released by the first electrode group 2 and / or the second electrode group 3 will be blocked in advance by the protective cover 4, thereby preventing impurities from being deposited on the inner wall of the insulating shell 1, avoiding the inner wall of the insulating shell 1 from being contaminated, and improving the insulation resistance of the insulating shell 1, thereby reducing the loss value of the vacuum capacitor and improving the service life, meeting the needs of high frequency, low loss and long life in the field of semiconductor manufacturing equipment.

[0033] It should be noted that the length of the protective cover 4 in the present invention and its installation position in the axial direction of the vacuum capacitor are not restricted. That is to say, the length and installation position of the protective cover 4 are reasonably set according to needs, so that the protective cover 4 can be located between the insulating shell 1 and the first electrode group 2, or between the insulating shell 1 and the second electrode group 3, or between the insulating shell 1 and the first electrode group 2 and the second electrode group 3 at the same time.

[0034] Illustratively, the insulating shell 1 can be made of ceramic material; the protective cover 4 can be made of metal material, which can withstand the high temperature environment during the production process. In this embodiment, the specific material used for the protective cover 4 is the same as that of the first electrode group 2 and the second electrode group 3, both of which are pure copper with an impurity content of ≤0.03%.

[0035] Furthermore, 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 .

[0036] like Figure 1 As shown, in this embodiment, the flange portion 402 on the protective cover 4 can be regarded as being formed by folding the lower end of the annular portion 401 outward by 90°. The flange portion 402 is fixedly connected to the insulating shell 1, and a gap is left between the annular portion 401 and the insulating shell 1 and the first electrode group 2 and / or the second electrode group 3.

[0037] In this embodiment, the annular portion 401 is located between the upper half of the insulating housing 1 and the first electrode group 2. The lower end of the annular portion 401 radially overlaps the upper end of the second electrode group 3. The spacing between the annular portion 401 and the insulating housing 1 is L1, and the spacing between the annular portion 401 and the first electrode group 2 and the second electrode group 3 is L2 and L3, respectively. The spacing between the electrode rings of the first electrode group 2 and the second electrode group 3 is L0. L1, L2, and L3 are all greater than L0 to prevent the withstand voltage at both ends of the vacuum capacitor from being affected by the protective cover 4 and decreasing.

[0038] Continue reading Figure 1 In this embodiment, two insulating housings 1 are provided. The two insulating housings 1 are sealed and fixedly connected to the two sides of the flange portion 402. The flange portion 402 and the insulating housing 1 are fixed by, but not limited to, brazing, resistance welding, laser welding, etc. The two insulating housings 1 can be of equal length or one longer and one shorter, and this is not limited in the present invention.

[0039] As an option, the outer circumference of the flange portion 402 is flush with the outer circumference of the insulating housing 1 (eg Figure 1 As shown), the outer circumferential surface of the flange portion 402 is inwardly recessed compared to the outer circumferential surface of the insulating housing 1, or the flange portion 402 protrudes radially outward from the outer circumferential surface of the insulating housing 1.

[0040] Preferably, the upper end of the annular portion 401 extends toward the axial direction of the vacuum capacitor and extends beyond the corresponding end face of the insulating shell 1. This can provide a better impurity blocking effect on the one hand, and on the other hand, can avoid the influence of the uneven electric field caused by uneven solder flow and eccentric assembly of parts at the welding point between the insulating shell 1 and the first electrode disk 6 on the capacitor's load voltage. At the same time, the upper end of the annular portion 401 does not contact the first electrode disk 6, and the distance between the annular portion 401 and the first electrode disk 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, so as to prevent the withstand voltage at both ends of the vacuum capacitor from being affected by the protective cover and decreasing.

[0041] See Figure 2 The upper end of the annular portion 401 is bent outward, and the mouth of the annular portion 401 is set to a rounded corner 4011 formed by chamfering to prevent the protective cover 4 from discharging with the first electrode disk 6 under the alternating electric field, causing unstable working voltage of the capacitor.

[0042] During the long-term high-frequency and high-voltage operation 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. The released gas will cause the vacuum degree of the capacitor to decrease, which will also reduce the voltage resistance and service life of the vacuum capacitor.

[0043] In this regard, the present invention fixes an air-gettering element 5 on the protective cover 4, and utilizes the air-gettering element 5 to absorb the gas released from the electrode material, thereby maintaining the vacuum degree inside the vacuum capacitor, thereby improving the pressure resistance and service life of the vacuum capacitor.

[0044] Getter element 5 is made from multi-element alloy powder sintered at high temperature on a metal substrate. It is a high-density, non-evaporable getter. After high-temperature activation, this getter can adsorb gases for extended periods at room temperature. This manufacturing process is conventional. The resulting getter element 5 is an annular structure, wrapped around the outer and / or inner walls of the annular portion 401.

[0045] Compared with the traditional arrangement of the air-intake element, the present application arranges the air-intake element in a ring shape and wraps it on the ring part of the protective cover. Therefore, the capacity of the air-intake element can be greatly improved, and it has a larger adsorption area, which significantly enhances the ability of the air-intake element to adsorb the gas released from the electrode material for a long time. In addition, the air-intake element of the present application is directly close to the gas release source, forming an annular enclosed adsorption area, which significantly improves the adsorption efficiency, can maintain the vacuum degree inside the vacuum capacitor for a long time, and further improve the pressure resistance and service life of the vacuum capacitor.

[0046] When the getter element 5 is fixed on the outer wall of the annular portion 401, the distance between the getter element 5 and the insulating shell 1 should 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; when the getter element 5 is fixed on the inner wall of the annular portion 401, the distance between the getter element 5 and the first electrode group 2 and the second electrode group 3 should 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, so as to prevent the withstand voltage at both ends of the vacuum capacitor from being reduced due to the influence of the getter element 5.

[0047] To facilitate production, in this embodiment, the getter element 5 is fixed to the outer wall of the annular portion 401 . The fixing method may be, but is not limited to, resistance welding or laser welding.

[0048] In order to verify the technical effect of the present invention, the vacuum degree and insulation resistance of the vacuum capacitor of the present invention and a conventional vacuum capacitor of the same specifications but without the protective cover 4 and the getter element 5 were tested during operation. The test results are shown in the following table: Table 1 Product serial number Capacitance (pF) Vacuum degree (Pa) Insulation resistance (MΩ) Traditional vacuum capacitors 252 5.02E-04 2.4E+06 Vacuum capacitor of the present invention 220.1 1.98E-04 1.0E+08 As shown in the table, the difference in capacitance between the vacuum capacitor of the present invention and the conventional vacuum capacitor is due to the following: in products of the same specifications, due to insufficient space, in order to add the protective cover 4, it is necessary to remove the outermost electrode ring inside the vacuum capacitor to provide space for the installation of the protective cover 4. The reduction of the electrode ring directly causes the capacitance of the vacuum capacitor of the present invention to be smaller than that of the conventional vacuum capacitor. However, this capacitance difference does not significantly affect the test results of the vacuum degree and insulation resistance.

[0049] As can be seen from the above table, the present invention greatly improves the insulation resistance and vacuum degree of the insulating shell 1 by providing the protective cover 4 and wrapping the air-intake element 5 on the annular portion 401 of the protective cover 4, thereby increasing the service life of the vacuum capacitor.

[0050] Example 2

[0051] See Figure 3 and Figure 4 This embodiment differs from the first embodiment in that the flange portion 402 of the protective cover 4 protrudes radially 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.

[0052] Example 3

[0053] See Figure 5This 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.

[0054] 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.

[0055] Example 4

[0056] 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.

[0057] Example 5

[0058] 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.

[0059] 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.

[0060] Example 6

[0061] 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.

[0062] 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.

[0063] Example 7

[0064] The difference between this embodiment and any one of the embodiments from first to sixth is that in this embodiment, the vacuum capacitor is a variable vacuum capacitor, that is, 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 so that its capacitance can be adjusted.

[0065] Specifically, see Figure 9 The vacuum capacitor includes an insulating shell 1, a first electrode group 2, a second electrode group 3, a movable electrode disk 8, a fixed electrode disk 9, an end cover 10, a bellows 11, a transmission mechanism, and the protective cover 4 and the air-intake element 5 described in any one of the embodiments 1 to 6.

[0066] The end caps 10 and the fixed electrode disc 9 are respectively seal-welded to both ends of the insulating housing 1. The movable electrode disc 8 is located in a cavity enclosed by the end caps 10, the fixed electrode disc 9, and the insulating housing 1. The movable electrode disc 8 is seal-connected to the end caps 10 via a bellows 11, thereby forming a vacuum chamber 101 between the insulating housing 1, the end caps 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 jointly 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 surfaces of the movable electrode disc 8 and the fixed electrode disc 9 facing each other.

[0067] The transmission mechanism includes a screw 12 and a pull rod 13. A sleeve 14 is fixed to the end cap 10. The screw 12 is rotatably mounted on the sleeve 14 via a bearing. Its axial movement is restricted, meaning it can only rotate. The pull rod 13 is high-temperature welded to the center of the moving electrode disk 8. Its upper end passes through the bellows 11 and is provided with a threaded hole. The screw 12 is threadedly connected to the threaded hole in the pull rod 13.

[0068] When the motor drives the screw 12 to rotate, the screw 12 will drive the pull rod 13 to move up and down along the axial direction, and synchronously drive the electrode disk 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.

[0069] The structure and assembly method of the protective cover 4 and the air suction element 5 may adopt any one of the implementations in the first to sixth embodiments, and will not be repeated here.

[0070] Thus, the present invention provides a vacuum capacitor. By providing a protective cover 4 between the insulating shell 1 and the first electrode group 2 and / or the second electrode group 3, during long-term high-frequency and high-voltage operation, impurities released by the first electrode group 2 and / or the second electrode group 3 will be blocked in advance by the protective cover 4, thereby preventing impurities from being deposited on the inner wall of the insulating shell 1, avoiding contamination of the inner wall of the insulating shell 1, and improving the insulation resistance of the insulating shell 1, thereby reducing the loss value of the vacuum capacitor and increasing the service life, meeting the requirements of high frequency, low loss and long life in the field of semiconductor manufacturing equipment; at the same time, compared with the arrangement of traditional getter elements, the present application arranges the getter element 5 in an annular shape and wraps it around the annular portion 401 of the protective cover 4. Therefore, the capacity of the getter element 5 can be greatly increased, and it has a larger adsorption area, significantly enhancing the ability of the getter element 5 to adsorb the gas released from the electrode material for a long time. In addition, the getter element 5 of the present application is directly close to the gas release source, forming an annular enclosed adsorption area, which significantly improves the adsorption efficiency, can maintain the vacuum degree inside the vacuum capacitor for a long time, and further improves the pressure resistance and service life of the vacuum capacitor.

[0071] The same or similar parts between the various embodiments in this specification can be referred to each other, and each embodiment focuses on the differences from other embodiments.

[0072] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection 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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