Ultra-high precision variable vacuum capacitor

Abstract

This invention discloses an ultra-high precision variable vacuum capacitor, comprising a vacuum capacitor body, two electrode groups, and a pull rod fixedly connected to one of the electrode groups. The pull rod, driven by an external power device, moves the connected electrode group axially, thereby changing the coupling length between the two electrode groups. A position holder is installed at one end of the vacuum capacitor body. The position holder has a retaining hole inside and multiple ball bearings evenly distributed around the retaining hole. The pull rod extends axially through one end of the vacuum capacitor body and inserts into the retaining hole, with its outer circumferential surface abutting against the multiple ball bearings. This invention, by having multiple ball bearings evenly distributed around the retaining hole in the position holder abut against the pull rod, ensures that the electrode group connected to the pull rod has no radial displacement, guaranteeing the ultra-high precision of the variable vacuum capacitor.

Description

Technical Field

[0001] This utility model relates to the field of vacuum capacitor technology, and in particular to an ultra-high precision variable vacuum capacitor. Background Technology

[0002] A variable vacuum capacitor is an electronic component that changes its capacitance by altering the coupling length or coupling area between electrodes. It is widely used in equipment such as broadcasting, medical MRI, high-frequency heating, semiconductor etching, and plasma cleaning. Especially in high-end manufacturing fields such as semiconductor etching equipment where extremely high capacitance precision is required, the precise control of its capacitance directly affects the performance of the equipment and the quality of the products.

[0003] However, traditional variable vacuum capacitors have many problems. On the one hand, to ensure the normal operation of the internal transmission mechanism, a small gap must be maintained between the mechanisms, and due to limitations in machining precision, it is difficult to achieve a high degree of straightness in the transmission components. Therefore, during use, the capacitance value of vacuum capacitors will deviate due to changes in installation position (affected by gravity), angle, ambient temperature, and operating temperature, which directly affects the accuracy of etching equipment and wafer yield, resulting in significant production losses.

[0004] On the other hand, variable vacuum capacitors contain internal elastic elements (such as bellows), and due to the gaps in the transmission mechanism, the elastic elements cannot achieve 360° force balance. Therefore, the electrode plates experience unpredictable radial displacement, making it difficult to overcome the accuracy bottleneck of variable vacuum capacitors. Furthermore, because this radial displacement is random, the motor control system cannot effectively compensate for this error. While adding a capacitance sensor for capacitance feedback can improve capacitance accuracy to some extent, the capacitance sensor cannot function properly in certain special environments (such as radio frequency environments), and due to the unpredictable displacement of the vacuum capacitor's mechanical structure, capacitance jumps can occur, making the success rate of the capacitance sensor feedback solution less than 100%. Additionally, its high cost increases production costs. In summary, these shortcomings of traditional variable vacuum capacitors severely restrict their application and development in high-end fields and urgently require improvement. Utility Model Content

[0005] The problem to be solved by this invention is to provide an ultra-high precision variable vacuum capacitor to overcome the defect of low capacitance accuracy of traditional variable vacuum capacitors.

[0006] The technical solution adopted by this utility model to solve its technical problem is as follows: an ultra-high precision variable vacuum capacitor, including a vacuum capacitor body, the vacuum capacitor body including two mutually coupled electrode groups and a pull rod fixedly connected to one of the electrode groups, the pull rod being used to drive the electrode group connected to it to move axially under the drive of an external power device, so as to change the coupling length between the two electrode groups; a position holder is installed at one end of the vacuum capacitor body, the position holder has a holding hole inside, and a plurality of ball bearings are evenly distributed around the holding hole on the position holder; the pull rod extends outward along the axial direction through one end of the vacuum capacitor body and inserts into the holding hole, while the outer circumferential surface of the pull rod abuts against the plurality of ball bearings.

[0007] As a further improvement of this utility model, the position holder includes a sleeve portion, the retaining hole is formed in the sleeve portion, and the sleeve portion is adjustable to change the diameter of the retaining hole.

[0008] As a further improvement of this utility model, the sleeve portion is provided with a notch that passes through both ends of its axial direction, and the parts of the sleeve portion on both sides of the notch extend outward to form two opposing adjusting plates. A fastener is installed between the two adjusting plates. When the fastener is adjusted to bring the two adjusting plates closer together, the retaining hole is reduced.

[0009] As a further improvement of this utility model, the sleeve portion is provided with a plurality of ball guide grooves along the inner wall, and the plurality of ball groups are correspondingly accommodated in the plurality of ball guide grooves, and at least partially exposed to the ball guide grooves protruding into the interior of the sleeve portion.

[0010] As a further improvement of this utility model, the ball guide grooves are all distributed parallel to the axis of the sleeve portion, and the ball assembly is composed of several balls arranged in a row along the ball guide grooves.

[0011] As a further improvement of this utility model, each ball guide groove includes two straight guide grooves distributed parallel to the axis of the sleeve portion and two curved guide grooves connecting the ends of the two straight guide grooves. Each ball group includes a plurality of balls, which are arranged along the two straight guide grooves and the two curved guide grooves, and the plurality of balls circulate within the ball guide grooves.

[0012] As a further improvement of this utility model, one end of the sleeve portion extends radially outward to form a flange portion, and the flange portion is fixed to one end of the vacuum capacitor body.

[0013] As a further improvement of this utility model, the vacuum capacitor body also includes a ceramic tube, a base, and a bellows. The two electrode groups are a moving electrode group and a fixed electrode group, respectively. The fixed electrode group and the base are respectively welded to the two ends of the ceramic tube. The two ends of the bellows are respectively welded to the moving electrode group and the base. A guide sleeve is fixed in the middle of the base, and the pull rod slides through the guide sleeve.

[0014] As a further improvement of this utility model, the flange is fixed to the base by a number of screws.

[0015] As a further improvement of this utility model, the ultra-high precision variable vacuum capacitor also includes a sleeve, a rotating screw, and a positioning nut. The sleeve is fixed to the end of the position holder away from the vacuum capacitor body, the positioning nut is fixed to the end of the pull rod away from the electrode group, and the rotating screw is rotatably mounted on the sleeve and threadedly connected to the positioning nut.

[0016] The beneficial effects of this utility model are as follows: This utility model provides an ultra-high precision variable vacuum capacitor. By installing a position holder at one end of the vacuum capacitor body, and setting multiple ball bearings evenly distributed around the holding hole in the position holder to abut against the outer circumferential surface of the pull rod, the radial displacement of the pull rod can be effectively limited, ensuring that the electrode assembly connected to the pull rod has no radial displacement. This ensures that the pull rod and its connected electrode assembly are more stable during movement, reducing capacitance deviation caused by displacement, thereby ensuring the ultra-high precision of the variable vacuum capacitor. At the same time, this utility model configures the sleeve of the position holder to be adjustable, which can change the diameter of the holding hole. The sleeve can be adjusted according to the actual assembly requirements, so that multiple ball bearings abut against the pull rod, achieving zero-clearance fit between the pull rod and the position holder. This maintains the relative position stability of the pull rod and the electrode assembly, avoiding the capacitance being affected by the installation position, angle, and environmental factors. At the same time, it ensures that the electrode assembly of the variable vacuum capacitor will not have radial displacement or swaying during capacitance adjustment, making the variable vacuum capacitor extremely stable during capacitance adjustment and truly achieving ultra-high precision zero-error adjustment. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a perspective view of the ultra-high precision variable vacuum capacitor of this utility model; Figure 2 This is an exploded view of the ultra-high precision variable vacuum capacitor of this utility model; Figure 3 This is a cross-sectional view of the ultra-high precision variable vacuum capacitor of this utility model; Figure 4 This is a perspective view of the position holder in the ultra-high precision variable vacuum capacitor of this utility model; Figure 5 This is a cross-sectional view of the position holder in the ultra-high precision variable vacuum capacitor of this utility model; Figure 6 This is a capacitance test curve for a traditional variable vacuum capacitor without a position holder. Figure 7 This is a capacitance value test curve of the ultra-high precision variable vacuum capacitor of this utility model.

[0019] Referring to the accompanying drawings, the following explanations are provided: 1. Pull rod; 2. Position retainer; 201. Retaining hole; 202. Ball assembly; 203. Sleeve section; 2031. Ball guide groove; 20311. Straight guide groove; 20312. Bent guide groove; 204. Adjusting plate; 205. Fastener; 206. Flange section; 3. Ceramic tube; 4. Base; 5. Bellows; 6. Moving electrode assembly; 7. Fixed electrode assembly; 8. Guide sleeve; 9. Screw; 10. Sleeve; 11. Rotating screw; 12. Locating nut. Detailed Implementation

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0025] See Figures 1 to 5 This utility model provides an ultra-high precision variable vacuum capacitor, including a vacuum capacitor body. The vacuum capacitor body includes two mutually coupled electrode groups and a pull rod 1 fixedly connected to one of the electrode groups. The pull rod 1 is used to drive the electrode group connected to it to move axially under the drive of an external power device, so as to change the coupling length between the two electrode groups, thereby changing the capacitance value of the vacuum capacitor body.

[0026] As an important improvement of this utility model, a position holder 2 is fixedly installed on the upper end of the vacuum capacitor body. The position holder 2 has a holding hole 201 inside, and multiple ball bearing sets 202 are evenly distributed around the holding hole 201 on the position holder 2. The pull rod 1 extends outward along the axial direction through the upper end of the vacuum capacitor body and is inserted into the holding hole 201. At the same time, the outer circumferential surface of the pull rod 1 abuts against the multiple ball bearing sets 202, which can effectively limit the radial displacement of the pull rod 1, so that the electrode group connected to the pull rod 1 has no radial displacement. This ensures that the pull rod 1 and the electrode group connected to it are more stable during movement, reduces the capacitance deviation caused by displacement, and thus ensures the ultra-high precision of the variable vacuum capacitor. For applications such as etching equipment that have extremely high requirements for capacitance precision, this can greatly improve equipment precision, ensure wafer yield, and improve production efficiency and product quality.

[0027] The position holder 2 includes a sleeve portion 203 that is open at both the top and bottom and hollow inside, and a retaining hole 201 is formed inside the sleeve portion 203.

[0028] It is worth mentioning that the sleeve portion 203 is adjustable, used to change the diameter of the retaining hole 201. Since the manufacturing process of the position retainer 2 cannot be completely error-free, this utility model configures the sleeve portion 203 of the position retainer 2 to be adjustable, capable of changing the diameter of the retaining hole 201. The sleeve portion 203 can be adjusted according to actual assembly requirements, so that multiple ball bearing assemblies 202 all abut against the pull rod 1, achieving zero-clearance fit between the pull rod 1 and the position retainer 2, maintaining the relative position stability of the pull rod 1 and the electrode assembly. This ensures that the electrode assembly will not experience radial displacement due to clearance, causing accuracy errors, regardless of the installation angle or operating temperature. It avoids the capacitance value being affected by the installation position, angle, and environmental factors. At the same time, it ensures that the electrode assembly of the variable vacuum capacitor will not experience radial displacement or oscillation during capacitance adjustment, making the variable vacuum capacitor extremely stable during capacitance adjustment, truly achieving high-precision zero-error adjustment.

[0029] See Figure 4 The sleeve portion 203 has a notch. Axially, the notch extends through both ends of the sleeve portion 203. Radially, the notch extends through both the inner and outer surfaces of the sleeve portion 203. This notch prevents the sleeve portion 203 from forming a complete annular structure. The portions of the sleeve portion 203 on both sides of the notch extend outwards, forming two opposing adjusting plates 204. A fastener 205 is installed between the two adjusting plates 204. When the fastener 205 is adjusted to bring the two adjusting plates 204 closer together, the retaining hole 201 narrows.

[0030] Specifically, the fastener 205 uses an adjusting screw and an adjusting nut. Both adjusting plates 204 are provided with through holes. The adjusting screw passes through the through holes on the two adjusting plates 204 and connects to the adjusting nut. By locking the adjusting screw and the adjusting nut, the two adjusting plates 204 are brought together to tighten the sleeve part 203 to achieve fine adjustment, thereby ensuring that multiple ball bearing groups 202 abut against the pull rod 1, achieving zero clearance fit between the pull rod 1 and the position retainer 2.

[0031] Of course, fastener 205 can also be made of adjusting screws. By having a through hole on one adjusting plate 204 and a threaded hole on the other adjusting plate 204, the adjusting screw can be threaded into the threaded hole after passing through the through hole, thus achieving the same adjustment function.

[0032] See Figure 4 and Figure 5 The sleeve portion 203 has a plurality of ball guide grooves 2031 along its inner wall. The plurality of ball guide grooves 2031 extend along the axial direction of the sleeve portion 203 and are distributed in a ring at equal intervals. A plurality of ball assemblies 202 are correspondingly housed in the plurality of ball guide grooves 2031 and at least partially protrude into the interior of the sleeve portion 203 to abut against the pull rod 1.

[0033] Each ball guide groove 2031 includes two straight guide grooves 20311 distributed parallel to the axis of the sleeve portion 203 and two curved guide grooves 20312 connecting the ends of the two straight guide grooves 20311, thereby forming an annular guide groove with the ends connected.

[0034] For ease of distinction, the two straight guide grooves 20311 in the ball guide groove 2031 are defined as the inner straight guide groove and the outer straight guide groove, respectively. In this embodiment, for any one of the ball guide grooves 2031, the inner straight guide groove extends through the inner wall of the sleeve portion 203, and the outer straight guide groove is located on one side of the inner straight guide groove along the radial direction of the sleeve portion 203, with a partition between the inner and outer straight guide grooves. One curved guide groove 20312 is connected to the upper end of the two straight guide grooves 20311, and the other curved guide groove 20312 is connected to the lower end of the two straight guide grooves 20311.

[0035] Furthermore, each ball assembly 202 includes a number of balls, which are arranged along two straight guide grooves 20311 and two curved guide grooves 20312, and the balls circulate within the ball guide grooves 2031.

[0036] In this invention, the ball bearing guide groove 2031 has a straight guide groove 20311 and a curved guide groove 20312 distributed parallel to the axis of the sleeve portion 203. The straight guide groove 20311 provides a stable and linear motion path for the ball assembly, enabling the pull rod 1 to obtain smooth support and guidance during axial movement. The curved guide groove 20312 achieves a smooth transition in the movement direction of the ball assembly, realizing the cyclic rolling of the balls. This allows each ball to evenly distribute the pressure and friction from the pull rod 1, preventing excessive wear of some balls and extending the service life of the ball assembly and the entire position retainer. At the same time, the uniform force distribution also helps maintain the stable support of the ball assembly for the pull rod, ensuring the long-term stable operation of the variable vacuum capacitor.

[0037] In this embodiment, the position holder 2 has 20 rows of two layers of 1.3mm diameter balls, which have sufficient contact surface with the middle pull rod 1 to prevent wear from being accelerated and reducing life due to insufficient contact surface.

[0038] Of course, in some other embodiments of this utility model, the ball guide groove 2031 can also be configured as a single-layer structure, that is, the ball guide groove 2031 is only a straight guide groove 20311 parallel to the axis of the sleeve part 203, and the ball group 202 is composed of several balls arranged in a row along the ball guide groove 2031.

[0039] Furthermore, the lower end of the sleeve portion 203 extends radially outward to form a flange portion 206, which is fixed to the upper end of the vacuum capacitor body.

[0040] In this invention, the two electrode groups are a moving electrode group 6 and a fixed electrode group 7. The moving electrode group 6 includes a moving disk and a moving electrode ring group. The moving electrode ring group is fixed to the end face of the moving disk facing the fixed electrode group 7, and the lower end of the pull rod 1 is welded to the middle of the moving disk. The fixed electrode group 7 includes a stator disk and a fixed electrode ring group. The fixed electrode ring group is fixed to the end face of the stator disk facing the moving electrode group 6, and the fixed electrode ring group and the moving electrode ring group are coupled to each other.

[0041] For example, both the fixed electrode ring group and the moving electrode ring group can be composed of multiple electrode rings of different diameters coaxially spaced together. The electrode rings of the fixed electrode ring group and the moving electrode ring group are arranged alternately from the inside to the outside, and the spacing between two adjacent electrode rings is the same. At the same time, the electrode rings of the fixed electrode ring group and the moving electrode ring group have at least a portion extending into each other, and the relatively overlapping portion is the coupling length of the fixed electrode ring group and the moving electrode ring group.

[0042] In addition, the vacuum capacitor body also includes a ceramic tube 3, a base 4, a bellows 5, and a guide sleeve 8, all of which are based on existing conventional technologies.

[0043] The ceramic tube 3 is a round tube with open ends. It is made of ceramic material and has excellent insulation properties, which can ensure that the variable vacuum capacitor can work safely and stably in a high-voltage environment. At the same time, it has high mechanical strength, which helps to maintain the vacuum state inside the vacuum capacitor body.

[0044] Both the base 4 and the stator plate are circular, and the base 4 and the stator plate are welded to the upper and lower ends of the ceramic tube 3 respectively by connecting rings. Alternatively, the connecting rings can be directly machined integrally onto the base 4 and the stator plate.

[0045] The moving electrode assembly 6 is located in the cavity formed by the ceramic tube 3, the base 4, and the stator disk. The two ends of the bellows 5 are welded to the moving electrode assembly 6 and the base 4, respectively. The stator disk, the ceramic tube 3, the base 4, the bellows 5, and the moving disk together form a closed space, which is configured as a vacuum chamber. Both the stator electrode ring assembly and the moving electrode ring assembly are sealed in the vacuum chamber.

[0046] The guide sleeve 8 is fixed to the middle of the base 4 and extends toward the inside of the bellows 5, and the pull rod 1 is slidably fitted inside the guide sleeve 8.

[0047] See Figure 1 and Figure 2 The top surface of the base 4 is provided with several mounting threaded holes, and the flange 206 is provided with mounting holes that correspond one-to-one with the mounting threaded holes. Several screws 9 are passed through the mounting holes and locked in the mounting threaded holes to fix the position retainer 2 to the base 4.

[0048] It should be noted that the mounting hole on the flange 206 should be at a certain distance from the notch on the sleeve 203 so that the subsequent fine-tuning of the position retainer 2 can be carried out smoothly.

[0049] See Figure 2 and Figure 3 The ultra-high precision variable vacuum capacitor also includes a sleeve 10, a rotating screw 11, and a positioning nut 12. The sleeve 10 is fixed to the end of the position holder 2 away from the vacuum capacitor body, and the positioning nut 12 is fixed to the end of the pull rod 1 away from the electrode assembly. The rotating screw 11 is rotatably mounted on the sleeve 10 via a bearing and is threadedly connected to the positioning nut 12. The upper end of the rotating screw 11 can be connected to an external power device (such as a motor) through a transmission mechanism. When the external power device drives the rotating screw 11 to rotate through the transmission mechanism, the positioning nut 12 drives the pull rod 1 and the moving electrode assembly 6 to move axially.

[0050] The assembly process of the position holder 2 of this utility model is as follows: During assembly, the position retainer 2 is fitted onto the upper end of the tie rod 1, and the mounting hole on the flange 206 is aligned with the mounting threaded hole on the base 4. It is then secured using screws 9. Next, the gap between the tie rod 1 and the position retainer 2 is tested, including capacitance values ​​at different angles and under vibration, as detailed below: Adjust the fastener 205 on the position holder 2 until the capacitance value is the same in all four directions (0°, 90°, 180°, and 270°) when the vacuum capacitor body is placed horizontally.

[0051] Then, the sleeve 10, rotating screw 11 and positioning nut 12 are installed, and the motor drive system is connected to form an electromechanical variable vacuum capacitor.

[0052] Finally, the capacitance accuracy of the mechatronic variable vacuum capacitor is adjusted. The position capacitance curve is collected by the host computer, and the data is fed into the motor drive board to collect the capacitance accuracy, that is, to compare the set standard capacitance value with the measured capacitance value.

[0053] Figure 6 The graph shown is a capacitance test curve of a conventional variable vacuum capacitor without a position holder. Figure 7 The image shows the capacitance test curve of the ultra-high precision variable vacuum capacitor of this invention. Figure 6 and Figure 7 In the diagram, the horizontal axis represents the nominal capacitance of the variable vacuum capacitor, continuously adjustable from 150pF to 1500pF by a motor drive; the vertical axis represents the capacitance accuracy deviation, in pF. Series 1 (blue line) and Series 2 (red line) on the top and bottom represent the 0.8% capacitance accuracy deviation specification line, Series 7 (purple line) and Series 9 (orange line) represent the 0.5% capacitance accuracy deviation specification line, and Series 3 (green line) in the middle represents the measurement accuracy deviation. Theoretically, the closer the deviation is to 0, the better; ideally, it should completely coincide with the horizontal axis. Theoretically, the capacitance accuracy can reach zero error, but actual testing revealed that due to environmental factors and errors in the measuring equipment itself, the variable vacuum capacitor of this invention exhibits only a slight systematic error in capacitance accuracy. The test curves show that the capacitance accuracy deviation of a traditional variable vacuum capacitor without a position holder is around 0.5%, while the capacitance deviation accuracy of this ultra-high precision variable vacuum capacitor is less than 0.05%.

[0054] In summary, this utility model of an ultra-high precision variable vacuum capacitor, by installing a position retainer 2 at one end of the vacuum capacitor body, and by setting multiple ball bearings 202 evenly distributed around the retaining hole 201 within the position retainer 2 to abut against the outer circumferential surface of the pull rod 1, can effectively limit the radial displacement of the pull rod 1, ensuring that the electrode assembly connected to the pull rod 1 has no radial displacement. This guarantees greater stability of the pull rod 1 and its connected electrode assembly during movement, reduces capacitance deviation caused by displacement, and thus ensures the ultra-high precision of the variable vacuum capacitor. Simultaneously, this utility model incorporates a sleeve for the position retainer 2... The sleeve part 203 is configured to be adjustable, which can change the diameter of the retaining hole 201. The sleeve part 203 can be adjusted according to the actual assembly requirements, so that multiple ball bearings 202 abut against the pull rod 1, realizing zero clearance fit between the pull rod 1 and the position retainer 2, keeping the relative position of the pull rod 1 and the electrode assembly stable, avoiding the capacitance value from being affected by the installation position, angle and environmental factors. At the same time, it ensures that the electrode assembly of the variable vacuum capacitor will not have radial displacement or swaying during capacitance adjustment, making the variable vacuum capacitor extremely stable during capacitance adjustment, and truly achieving ultra-high precision zero-error adjustment.

[0055] This invention achieves ultra-high precision capacitor control through innovative mechanical structure design, eliminating the need for expensive capacitance sensors that are limited in radio frequency environments and avoiding problems such as capacitance jumps. This not only reduces production costs but also improves the feasibility and stability of the solution. It can be widely used in various applications requiring high precision of variable vacuum capacitors and has good market application prospects.

[0056] The same or similar parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments.

[0057] 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. An ultra-high precision variable vacuum capacitor comprising a vacuum capacitor body, said vacuum capacitor body comprising two mutually coupled electrode sets and a pull rod (1) fixedly connected to one of said electrode sets, said pull rod (1) being intended to bring the electrode set connected thereto into axial movement under the drive of an external power device, so that the coupling length between the two electrode sets changes; characterized in that, A position holder (2) is installed at one end of the vacuum capacitor body. The position holder (2) has a retaining hole (201) inside. The position holder (2) is provided with a plurality of ball bearings (202) evenly distributed around the retaining hole (201). The pull rod (1) extends outward along the axial direction through one end of the vacuum capacitor body and is inserted into the retaining hole (201). At the same time, the outer circumferential surface of the pull rod (1) abuts against the plurality of ball bearings (202).

2. The ultra-high precision variable vacuum capacitor according to claim 1, wherein The position holder (2) includes a sleeve portion (203), the retaining hole (201) is formed in the sleeve portion (203), and the sleeve portion (203) is adjustable for changing the diameter of the retaining hole (201).

3. The ultra-high precision variable vacuum capacitor according to claim 2, wherein The sleeve portion (203) is provided with a notch that passes through both ends of its axial direction, and the sleeve portion (203) extends outward on both sides of the notch to form two opposing adjusting plates (204). A fastener (205) is installed between the two adjusting plates (204). When the fastener (205) is adjusted to bring the two adjusting plates (204) closer together, the retaining hole (201) is reduced.

4. The ultra-high precision variable vacuum capacitor according to claim 3, wherein The sleeve portion (203) is provided with a plurality of ball guide grooves (2031) along its inner wall. A plurality of ball sets (202) are respectively housed in the plurality of ball guide grooves (2031) and at least partially exposed, protruding into the interior of the sleeve portion (203).

5. The ultra-high precision variable vacuum capacitor according to claim 4, wherein The ball guide grooves (2031) are all distributed parallel to the axis of the sleeve (203), and the ball groups (202) are all composed of a number of balls arranged in a row along the ball guide grooves (2031).

6. The ultra-high precision variable vacuum capacitor according to claim 4, wherein Each ball guide groove (2031) includes two straight guide grooves (20311) distributed parallel to the axis of the sleeve (203) and two curved guide grooves (20312) connecting the ends of the two straight guide grooves (20311). Each ball group (202) includes a plurality of balls, which are arranged along the two straight guide grooves (20311) and the two curved guide grooves (20312), and the plurality of balls circulate within the ball guide grooves (2031).

7. The ultra-high precision variable vacuum capacitor according to claim 2, wherein One end of the sleeve portion (203) extends radially outward to form a flange portion (206), which is fixed to one end of the vacuum capacitor body.

8. The ultra-high precision variable vacuum capacitor according to claim 7, wherein The vacuum capacitor body also includes a ceramic tube (3), a base (4) and a bellows (5). The two electrode groups are a moving electrode group (6) and a fixed electrode group (7). The fixed electrode group (7) and the base (4) are respectively welded to the two ends of the ceramic tube (3). The two ends of the bellows (5) are respectively welded to the moving electrode group (6) and the base (4). A guide sleeve (8) is fixed in the middle of the base (4). The pull rod (1) slides through the guide sleeve (8).

9. The ultra-high precision variable vacuum capacitor according to claim 8, wherein, The flange (206) is fixed to the base (4) by a number of screws (9).

10. The ultra-high precision variable vacuum capacitor according to claim 1, wherein It also includes a sleeve (10), a rotating screw (11) and a positioning nut (12). The sleeve (10) is fixed to the end of the position holder (2) away from the vacuum capacitor body. The positioning nut (12) is fixed to the end of the pull rod (1) away from the electrode group. The rotating screw (11) is rotatably mounted on the sleeve (10) and threadedly connected to the positioning nut (12).

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