Variable vacuum capacitor

Abstract

The utility model discloses a variable vacuum capacitor, which comprises a capacitor outer shell, two electrode ring groups accommodated in the capacitor outer shell, a positioning rod and a positioning sliding sleeve, wherein the positioning rod is fixedly connected to one electrode ring group and can drive the electrode ring group to axially move relative to the other electrode ring group; the positioning sliding sleeve is detachably installed on the capacitor outer shell in a welding mode, the positioning rod is arranged in the positioning sliding sleeve in a sliding fit mode, and the two electrode ring sets are concentrically distributed. The structural design of the detachable self-lubricating positioning sliding sleeve is adopted, and high-temperature welding is not needed, so that the positioning sliding sleeve does not generate stress and size changes, the size of an inner hole of the positioning sliding sleeve can be accurately controlled, the gap between the positioning sliding sleeve and the positioning rod can be stably controlled, and the service life of the positioning rod is prolonged. Therefore, the variable vacuum capacitor has stable capacitance value change and lower rotating torque, the capacitance value precision of the capacitor is improved, and the mechanical life of the capacitor is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of capacitor technology, and in particular to a variable vacuum capacitor. Background Technology

[0002] A vacuum capacitor is a type of capacitor with a ceramic insulating shell, a vacuum dielectric, and high-conductivity oxygen-free copper electrodes. Compared to other capacitors, it has advantages such as high voltage withstand capability, large current carrying capacity, low high-frequency loss, and self-healing ability after transient overload, making it particularly suitable for high-frequency, high-voltage applications. Vacuum capacitors are currently widely used in equipment such as broadcasting, medical MRI, high-frequency heating, semiconductor etching, and plasma cleaning. In these high-frequency devices, vacuum capacitors form resonant circuits with high-frequency inductors to achieve high-frequency impedance matching and ensure stable transmission of radio frequency power.

[0003] Figure 1 The diagram shows a cross-sectional view of an existing variable vacuum capacitor. Its moving electrode ring assembly 5 is welded and fixed to the positioning rod 2 via the moving disk 4. The positioning rod 2 is connected to the positioning nut 10 via threads. The positioning nut 10 is connected to the rotating screw 9 via threads. The rotating screw 9 is connected to an external motor. The motor drives the rotating screw 9 to rotate, which in turn causes the moving disk 4 and the moving electrode ring assembly 5 to move up and down via the positioning rod 2. This changes the coupling length between the moving electrode ring assembly 5 and the stationary electrode ring assembly 7, i.e., changes the coupling area, and the capacitance value of the capacitor changes accordingly, thus realizing the adjustment of the capacitance value of the variable capacitor.

[0004] To ensure that the position of the positioning rod 2 does not shift radially, affecting the concentricity of the upper and lower electrode rings and the distance between the electrodes, a guide sleeve 20 is typically provided on the outside of the positioning rod 2. The guide sleeve 20 is generally machined from metal bar stock and fixed to the base 12 by high-temperature brazing. After the high-temperature welding of the capacitor is completed, lubricating grease needs to be added between the guide sleeve 20 and the positioning rod 2 to ensure that the positioning rod 2 slides freely within the guide sleeve 20. Traditional metal guide sleeves 20, after high-temperature welding, experience changes in mechanical stress due to machining. Uneven stress release can cause changes in the inner diameter of the guide sleeve 20, such as elliptical development, leading to poor sliding or jamming between the positioning rod 2 and the guide sleeve 20 after welding. This affects the capacitance accuracy and the capacitor's torque value, ultimately impacting the mechanical life of the variable vacuum capacitor. Therefore, it is necessary to improve the existing technology to overcome its shortcomings. Utility Model Content

[0005] The problem to be solved by this utility model is to provide a variable vacuum capacitor to overcome the defects of existing variable vacuum capacitors, which are affected by poor sliding or jamming of the positioning rod due to high-temperature welding, thus affecting the capacitance accuracy and the magnitude of the capacitor's torque, and ultimately affecting the mechanical life of the variable vacuum capacitor.

[0006] The technical solution adopted by this utility model to solve its technical problem is: a variable vacuum capacitor, comprising: a capacitor housing, two electrode ring groups housed in the capacitor housing, a positioning rod fixedly connected to one of the electrode ring groups and capable of driving the electrode ring group to move axially relative to the other electrode ring group, and a positioning slide sleeve. The positioning slide sleeve is detachably installed on the capacitor housing by means other than welding. The positioning rod is slidably engaged in the positioning slide sleeve, so that the two electrode ring groups are concentrically distributed.

[0007] As a further improvement of this utility model, the capacitor housing includes an insulating shell and a base sealed and fixed to one end of the insulating shell, and the positioning sleeve is fixed to the base.

[0008] As a further improvement of this utility model, the base is provided with a through hole in the middle, one end of the positioning sleeve passes through the through hole and extends into the capacitor housing, and the other end of the positioning sleeve is provided with a flange, the flange stops on the outer end face of the base, and the flange is fixed to the base by screws.

[0009] As a further improvement of this utility model, the variable vacuum capacitor also includes a moving disk, one of the two electrode ring groups is a moving electrode ring group, the moving electrode ring group and the positioning rod are both fixed to the moving disk, the moving disk and the base are sealed together by a bellows, thereby forming a sealed vacuum chamber inside the capacitor housing, and both electrode ring groups are housed in the vacuum chamber.

[0010] As a further improvement of this utility model, both the positioning rod and the positioning sleeve are located in the bellows, the positioning sleeve is provided with a gas passage, and the cavity inside the bellows is connected to the outside atmosphere through the gas passage.

[0011] As a further improvement of this utility model, the gas passage includes a plurality of air holes arranged axially on the positioning sleeve and a plurality of air grooves arranged radially on the end face of the positioning sleeve. One end of each of the plurality of air holes leads to the cavity inside the bellows, and the other end of each of the plurality of air holes is connected to the plurality of air grooves in a corresponding manner.

[0012] As a further improvement of this utility model, a lubricating coating is provided on the inner wall of the positioning sleeve.

[0013] As a further improvement of this utility model, the lubricating coating is a Teflon coating or a molybdenum disulfide coating.

[0014] As a further improvement of this utility model, the capacitor housing also includes a stator disk sealed and fixed to the other end of the insulating housing, and the other of the two electrode ring groups is a stationary electrode ring group, which is fixed to the stator disk.

[0015] As a further improvement of this utility model, the variable vacuum capacitor also includes a support sleeve and a transmission mechanism. The transmission mechanism includes a rotating screw and a positioning nut. The positioning nut is fixed to the positioning rod, and the rotating screw is rotatably mounted on the support sleeve and threadedly connected to the positioning nut.

[0016] The beneficial effects of this utility model are:

[0017] 1. This utility model provides a variable vacuum capacitor. By adopting a detachable self-lubricating positioning sleeve structure design, since high-temperature welding is not required, the positioning sleeve does not experience stress or dimensional changes. The inner hole size of the positioning sleeve can be precisely controlled, thereby ensuring that the gap between the positioning sleeve and the positioning rod is stable and controlled. This enables the variable vacuum capacitor to have stable capacitance changes and lower rotational torque, improving the capacitance accuracy and mechanical life of the capacitor, and meeting the user's demand for high capacitance accuracy and long life of the variable vacuum capacitor.

[0018] 2. By providing a lubricating coating on the inner wall of the positioning sleeve, this utility model can reduce the friction between the positioning sleeve and the positioning rod, and further reduce the rotational torque of the variable vacuum capacitor. In addition, the positioning sleeve with the lubricating coating no longer needs to be lubricated, and the positioning sleeve can be made of other low-temperature metal or plastic materials, which further reduces the manufacturing cost.

[0019] 3. This utility model provides a gas passage on the positioning sleeve, connecting the cavity inside the bellows to the outside atmosphere. During the capacitor capacitance adjustment process, the bellows is not affected by gas pressure and is in a uniform stress state, thereby ensuring stable capacitance changes and reducing torque fluctuations. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a cross-sectional view of an existing variable vacuum capacitor;

[0022] Figure 2 This is a perspective view of the variable vacuum capacitor of this utility model;

[0023] Figure 3 This is a cross-sectional view of the variable vacuum capacitor of this utility model;

[0024] Figure 4 This is a cross-sectional view of the positioning sliding sleeve in the variable vacuum capacitor of this utility model;

[0025] Figure 5 This is a perspective view of the positioning slide sleeve in the variable vacuum capacitor of this utility model.

[0026] Referring to the accompanying drawings, the following explanations are provided:

[0027] 1. Capacitor housing; 11. Insulating housing; 12. Base; 13. Stator plate; 101. Vacuum chamber; 2. Positioning rod; 3. Positioning sleeve; 301. Flange; 3011. Mounting hole; 302. Air hole; 303. Air groove; 304. Lubricating coating; 4. Moving plate; 5. Moving electrode ring assembly; 6. Bellows; 7. Stationary electrode ring assembly; 8. Support sleeve; 9. Rotating screw; 10. Positioning nut; 20. Guide sleeve. Detailed Implementation

[0028] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0029] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one 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 aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0031] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0033] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0034] See Figures 2 to 5 This utility model provides a variable vacuum capacitor, including: a capacitor housing 1, two electrode ring groups housed in the capacitor housing 1, a positioning rod 2 fixedly connected to one of the electrode ring groups and capable of driving the electrode ring group to move axially relative to the other electrode ring group, and a positioning slide sleeve 3.

[0035] It is worth mentioning that the positioning sleeve 3 in this utility model is installed on the capacitor housing 1 in a way other than welding, and the positioning rod 2 is slidably fitted inside the positioning sleeve 3, so that the two electrode ring groups are concentrically distributed.

[0036] In this way, after completing the welding of the two electrode ring assemblies and their related components (including the positioning rod 2) and the vacuuming of the capacitor, the positioning sleeve 3 can be installed on the capacitor housing 1 and fitted onto the positioning rod 2. Since the positioning sleeve 3 does not require high-temperature welding, it does not experience stress or dimensional changes. The inner diameter of the positioning sleeve 3 can be precisely controlled, ensuring a stable and controlled gap between the positioning sleeve 3 and the positioning rod 2. This reduces friction between them, resulting in a stable capacitance change and lower torque for the variable vacuum capacitor. This improves the capacitance accuracy and mechanical lifespan of the capacitor, meeting the user's requirements for high capacitance accuracy and long lifespan in variable vacuum capacitors.

[0037] It should be noted that, in order to ensure the assembly accuracy of the positioning rod 2, a fixture can be used to position the positioning rod 2 in place of the positioning sleeve 3 during the welding process. After welding is completed, the welding fixture is removed and the positioning sleeve 3 is then assembled.

[0038] Furthermore, in order to reduce the friction of the positioning rod 2 in the inner hole of the positioning sleeve 3, and thus further reduce the rotational torque of the capacitor, the present invention also provides a lubricating coating 304 on the inner wall surface of the positioning sleeve 3.

[0039] For example, the lubricating coating 304 can be a Teflon coating or a molybdenum disulfide coating, etc. In this embodiment, a Teflon coating is preferred. Teflon coating has properties such as high lubricity and excellent wear resistance. Its coefficient of friction is very low. The coefficient of friction between the conventional guide sleeve 20 and the positioning rod 2 is between 0.1 and 0.4. After adding a Teflon coating, the coefficient of friction can be reduced to 0.05 to 0.15.

[0040] Because the sintering temperature of the lubricating coating 304 (such as a Teflon coating or a molybdenum disulfide coating) is lower than the welding temperature of the capacitor, it is impossible to apply the lubricating coating 304 to the inner wall of the welded guide sleeve 20 of a conventional vacuum capacitor. However, this application, by using a detachable positioning sleeve 3, eliminates the need for high-temperature welding, thus allowing the lubricating coating 304 to be applied to the inner wall of the positioning sleeve 3. This reduces the friction between the positioning sleeve 3 and the positioning rod 2, resulting in a more stable capacitance change and lower torque in the variable vacuum capacitor. Furthermore, the positioning sleeve 3 with the lubricating coating 304 eliminates the need for additional lubricating grease, and the positioning sleeve 3 can be made of other low-temperature metals or plastics, further reducing manufacturing costs.

[0041] See Figure 2 and Figure 3 The capacitor housing 1 of this utility model includes an insulating housing 11, a base 12 and a stator disk 13. The insulating housing 11 is a cylindrical shape with open ends, and it is usually made of ceramic material. The base 12 and the stator disk 13 are respectively sealed and welded to the two ends of the insulating housing 11 at high temperature, thereby forming the capacitor housing 1.

[0042] In this utility model, the positioning sleeve 3 is fixed to the base 12.

[0043] Specifically, a through hole is provided in the middle of the base 12, the lower end of the positioning sleeve 3 passes through the through hole and extends into the capacitor housing 1, and the upper end of the positioning sleeve 3 is provided with a flange 301, which stops on the outer end face of the base 12 and is fixedly connected.

[0044] The flange 301 is provided with a plurality of mounting holes 3011 evenly distributed, and the base 12 is provided with a plurality of threaded holes corresponding to the plurality of mounting holes 3011. The flange 301 is locked and fixed in its mounting holes 3011 by screws and threaded holes.

[0045] like Figure 3As shown, in this embodiment, one of the two electrode ring groups is a moving electrode ring group 5, and the other is a stationary electrode ring group 7. The stationary electrode ring group 7 is welded to the inner end face of the stator disk 13 at high temperature. The variable vacuum capacitor also includes a moving disk 4. The moving electrode ring group 5 is welded to the bottom surface of the moving disk 4 at high temperature, and the positioning rod 2 is welded to the middle of the moving disk 4 at high temperature. At the same time, the moving disk 4 and the base 12 are sealed together by a bellows 6, thereby forming a sealed vacuum chamber 101 inside the capacitor housing 1.

[0046] The moving electrode ring group 5 and the stationary electrode ring group 7 are both composed of multiple electrode rings made of metal materials (such as oxygen-free copper) arranged concentrically at intervals. The electrode rings of the moving electrode ring group 5 and the electrode rings of the stationary electrode ring group 7 are arranged alternately and concentrically in the vacuum chamber 101 so that the electrode rings of the moving electrode ring group 5 and the electrode rings of the stationary electrode ring group 7 can couple with each other through the electric field formed between them.

[0047] In addition to this, the variable vacuum capacitor also includes a support sleeve 8 and a transmission mechanism. The support sleeve 8 is fixed to the top of the positioning slide sleeve 3. The transmission mechanism includes a rotating screw 9 and a positioning nut 10. The positioning nut 10 is fixed in the middle hole at the upper end of the positioning rod 2. The rotating screw 9 is rotatably mounted on the support sleeve 8 through a bearing and is threadedly connected to the positioning nut 10.

[0048] The rotating screw 9 is connected to an external motor drive. When the motor drives the rotating screw 9 to rotate, the rotating screw 9 will drive the positioning rod 2 to move axially through the positioning nut 10, and simultaneously drive the moving disk 4 and the moving electrode ring group 5 to move, so as to change the coupling area between the moving electrode ring group 5 and the stationary electrode ring group 7, thereby realizing the adjustment of the capacitor value.

[0049] In this invention, both the positioning rod 2 and the positioning sleeve 3 are located inside the bellows 6. During the capacitor capacitance adjustment process, the internal bellows 6 is in a state of continuous stretching and compression; that is, when the screw 9 is rotated clockwise, the positioning rod 2 moves axially upward, and the bellows 6 is compressed; when the screw 9 is rotated counterclockwise, the positioning rod 2 moves downward, and the bellows 6 is stretched. With the expansion and contraction of the bellows 6, the internal volume of the bellows 6 changes, and the internal gas pressure changes accordingly.

[0050] To further reduce the product's rotational torque and minimize torque fluctuations, this invention incorporates a gas passage on the positioning sleeve 3, through which the cavity inside the bellows 6 is connected to the external atmosphere. In this way, when the bellows 6 is compressed, the internal gas can be quickly discharged through the gas passage, and when the bellows 6 is stretched, external gas can smoothly enter the bellows 6 through the gas passage, ensuring the bellows 6 is under uniform stress, thereby guaranteeing stable capacitance changes and reducing torque fluctuations.

[0051] See Figure 4 and Figure 5 The positioning sleeve 3 has an enlarged diameter section near its upper end that connects to the flange 301. In this embodiment, the gas passage specifically includes multiple air holes 302 evenly arranged axially along the enlarged diameter section and multiple air grooves 303 evenly arranged radially along the upper surface of the positioning sleeve 3. The lower ends of each of the multiple air holes 302 lead to the cavity inside the bellows 6, and the upper ends of each of the multiple air holes 302 are connected to the multiple air grooves 303. The air grooves 303 prevent the air holes 302 from being blocked by the support sleeve 8, thus affecting the air inlet and outlet. By providing evenly distributed air holes 302 and air grooves 303 on the positioning sleeve 3, this utility model ensures that the bellows 6 is in a uniform stress state during capacitor capacitance adjustment, thereby ensuring stable capacitance changes and reducing torque fluctuations.

[0052] Therefore, this utility model provides a variable vacuum capacitor. By employing a detachable self-lubricating positioning sleeve 3, and eliminating the need for high-temperature welding, the positioning sleeve 3 does not experience stress or dimensional changes. The inner diameter of the positioning sleeve 3 can be precisely controlled, ensuring a stable and controlled gap between the positioning sleeve 3 and the positioning rod 2. This results in a stable capacitance change and lower torque for the variable vacuum capacitor, improving capacitance accuracy and mechanical lifespan, thus meeting users' demands for high capacitance accuracy and long lifespan. Furthermore, by providing a lubricating coating 304 on the inner wall of the positioning sleeve 3, this utility model reduces friction between the positioning sleeve 3 and the positioning rod 2, further reducing the torque of the variable vacuum capacitor. Moreover, the positioning sleeve 3 with the lubricating coating 304 eliminates the need for additional lubricating grease, and can be made of other low-temperature metals or plastics, further reducing manufacturing costs. Furthermore, by providing a gas passage on the positioning sleeve 3, the cavity inside the bellows 6 is connected to the outside atmosphere. During the adjustment of the capacitor value, the bellows 6 can be kept in a uniform stress state without being affected by gas pressure, thereby ensuring stable capacitance changes and reducing the fluctuation of rotational torque.

[0053] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A variable vacuum capacitor, comprising a capacitor housing (1), two electrode ring groups housed within the capacitor housing (1), a positioning rod (2) fixedly connected to one of the electrode ring groups and capable of axially moving the electrode ring group relative to the other electrode ring group, and a positioning sleeve (3), characterized in that: The positioning sleeve (3) is detachably mounted on the capacitor housing (1) by means other than welding. The positioning rod (2) is slidably fitted inside the positioning sleeve (3), so that the two electrode ring groups are concentrically distributed.

2. The variable vacuum capacitor according to claim 1, characterized in that: The capacitor housing (1) includes an insulating housing (11) and a base (12) sealed and fixed to one end of the insulating housing (11), and the positioning sleeve (3) is fixed to the base (12).

3. The variable vacuum capacitor according to claim 2, characterized in that: The base (12) has a through hole in the middle. One end of the positioning sleeve (3) passes through the through hole and extends into the capacitor housing (1). The other end of the positioning sleeve (3) has a flange (301). The flange (301) stops on the outer end face of the base (12), and the flange (301) is fixed to the base (12) by screws.

4. The variable vacuum capacitor according to claim 2, characterized in that: It also includes a moving disk (4), one of the two electrode ring groups is a moving electrode ring group (5), the moving electrode ring group (5) and the positioning rod (2) are both fixed to the moving disk (4), the moving disk (4) and the base (12) are sealed together by a bellows (6), thereby forming a sealed vacuum chamber (101) inside the capacitor housing (1), and both electrode ring groups are housed in the vacuum chamber (101).

5. The variable vacuum capacitor according to claim 4, characterized in that: The positioning rod (2) and the positioning sleeve (3) are both located in the bellows (6). The positioning sleeve (3) is provided with a gas passage, and the cavity inside the bellows (6) is connected to the outside atmosphere through the gas passage.

6. The variable vacuum capacitor according to claim 5, characterized in that: The gas passage includes a plurality of air holes (302) arranged axially on the positioning sleeve (3) and a plurality of air grooves (303) arranged radially on the end face of the positioning sleeve (3). One end of each of the plurality of air holes (302) leads to the cavity inside the bellows (6), and the other end of each of the plurality of air holes (302) is connected to the plurality of air grooves (303) in a corresponding manner.

7. The variable vacuum capacitor according to claim 1, characterized in that: The inner wall of the positioning sleeve (3) is provided with a lubricating coating (304).

8. The variable vacuum capacitor according to claim 7, characterized in that: The lubricating coating (304) is a Teflon coating or a molybdenum disulfide coating.

9. The variable vacuum capacitor according to claim 4, characterized in that: The capacitor housing (1) also includes a stator disk (13) sealed and fixed to the other end of the insulating housing (11), and the other of the two electrode ring groups is a stationary electrode ring group (7), which is fixed to the stator disk (13).

10. The variable vacuum capacitor according to claim 1, characterized in that: It also includes a support sleeve (8) and a transmission mechanism, the transmission mechanism including a rotating screw (9) and a positioning nut (10), the positioning nut (10) being fixed to the positioning rod (2), the rotating screw (9) being rotatably mounted on the support sleeve (8) and threadedly connected to the positioning nut (10).

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