Hollow cathode heating wire three-dimensional lead-out structure

Abstract

The application provides a hollow cathode heating wire three-dimensional leading-out structure which is composed of heat-conducting ceramic, heating wire, conductive leading-out wire, conductive limiting wire and insulating limiting sleeve; the hollow cathode itself is composed of a hollow cathode emitter and a hollow cathode tube; the heat-conducting ceramic is fixed outside the hollow cathode tube, the heating wire is wound in the spiral groove on the heat-conducting ceramic, one end of the heating wire is connected with the hollow cathode tube as a negative electrode, the other end is connected with the conductive leading-out wire as a positive electrode, the heating wire is wound on the straight section of the conductive leading-out wire for several turns, the circular ring part of the conductive leading-out wire is clamped at the end of the heat-conducting ceramic, the heating wire is spirally wound around the circular ring part of the conductive leading-out wire for one turn, the insulating limiting sleeve is sleeved on the straight section of the conductive leading-out wire, the two metal wires of the straight section of the conductive leading-out wire are respectively located on the left and right sides of the fin part of the conductive limiting wire, pass through the left and right limiting holes of the conductive limiting wire, and the front end of the conductive limiting wire is inserted into the insulating limiting sleeve.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of spaceflight electric propulsion, and particularly relates to the leading-out structure of a heating wire of a hollow cathode. BACKGROUND

[0002] With the development of commercial spaceflight and various satellites, the Hall thruster becomes the electric propulsion device with the largest number of on-orbit applications due to its simple structure, small size, high total impulse, and large thrust-to-power ratio. The Hall thruster needs to use a hollow cathode as an electron source and neutralizer, which is one of the core components of the Hall thruster. Long service life and high reliability are the main development directions of the hollow cathode at present. The start of the hollow cathode at present mostly uses the ohmic effect to pass a constant current to the heating wire, so as to heat the emitter from room temperature to 1600 DEG C. Therefore, as much heating power as possible needs to be provided on the unit length of the emitter. Therefore, the connection mode of the heating wire of the hollow cathode has a great influence on the hollow cathode.

[0003] According to the ohm law: under a constant current, the greater the resistance, the more obvious the heating effect. Therefore, in use, the resistance of the heating wire needs to be as large as possible, and the resistance of other conductive wires needs to be as small as possible. The result of the large resistance of the heating wire is that the heating power is large. However, the large heating power also easily leads to the melting and failure of the heating wire itself. Therefore, reducing the resistance of the conductive part that does not need to be heated is not only the requirement of the heating efficiency, but also the requirement of prolonging the service life.

[0004] In the current heating wire connection method, in order to reduce the useless resistance of the conductive wire, a thicker other material high-temperature resistant conductive metal wire is usually connected to the end of the heating wire. However, this method mostly causes the heating wire to have a right-angle turn or part of the heating wire to be suspended, or both of the two situations exist. The right-angle turn causes a strong stress concentration, so that the part becomes a weak part. The suspended part of the heating wire not only causes the system to have a reduced anti-vibration ability, but also causes the heat transfer between the heating wire and the heat-conducting ceramic to be performed in the form of heat radiation, so that the heat transfer effect is not as good as heat conduction, and the heating wire itself bears too much heating power, the temperature is increased, and the heating wire is melted.

[0005] Since the working temperature in the hollow cathode reaches 1600 DEG C, the heating wire mostly uses a tungsten wire or a rhenium-tungsten alloy wire and other high-temperature resistant metal wires. This brings great difficulty to the connection of the heating wire, and the relatively stable and reliable welding method cannot be used, and the soldering connection cannot be used. When the heating wire and the conductive leading-out metal wire are connected, only the two cylindrical sides are pasted together to form a line contact. In order to reduce the contact resistance, the length of the contact needs to be increased, the contact resistance needs to be reduced, the invalid power needs to be reduced, and when the contact resistance is very large, the connection part is also easily burned out due to the high temperature, so that the heating circuit is broken.

[0006] Therefore, it is necessary to find a connection mode which can avoid the suspension of the heating wire, avoid the stress concentration caused by the bending of the heating wire, have a larger contact area and smaller contact resistance between the heating wire and the conductive thick wire in a limited space, and ensure a certain anti-vibration performance.

[0007] To reduce the useless resistance of the conductive part as much as possible, the heating device part described in CN 112543522 A solves this problem, but the heating wire needs to complete a nearly right-angle turn, which will cause strong stress concentration and become a weak part of the heating wire. The cold end leading-out method described in CN 110335794 A still needs the heating wire to bend an angle in space, and also makes a part of the heating wire suspended, which not only causes the system anti-vibration ability to decrease, but also causes the heat transfer between the heating wire and the heat-conducting ceramic to be only in the form of heat radiation because the suspended part of the heating wire has no contact with the heat-conducting ceramic, resulting in a heat transfer effect that is not as good as heat conduction, causing the heating wire itself to bear too much heating power and the temperature to rise, resulting in a fuse. The contact between the heating wire and the conductive metal wire in the scheme is only linear contact, and due to the influence of the connection mode, the length of the connection section of the heating wire and the conductive leading-out wire cannot be extended indefinitely, and in the extreme case, it cannot exceed the length of the hollow cathode. In addition, the three leading-out wires mentioned in the patent are not axially fixed, and in severe and harsh conditions, the three metal wires and the heating wire clamped therebetween may be dislocated, resulting in an undesirable final conductive effect or even a circuit break. In the above two patents, the relative positions of the heat-conducting ceramic and the leading-out wire in the entire leading-out structure are not fixed, which makes the heating wire in contact with the heat-conducting ceramic and the leading-out wire very dangerous. Once the relative positions of the heat-conducting ceramic and the leading-out wire change, the heating wire will deform, causing fatigue damage over time, which is more obvious when there is a suspended part of the heating wire. Moreover, the heating wire is mostly made of tungsten wire, which becomes more brittle after being heated, so a new hollow cathode heating wire leading-out method is needed. SUMMARY

[0008] The problems of the suspension of the heating wire in the heater of the hollow cathode, the stress concentration caused by the turning of the heating wire, the small contact length and large contact resistance between the heating wire and the leading-out conductive wire, and the poor stability of the entire leading-out structure need to be solved.

[0009] The present application provides a new three-dimensional leading-out structure of the heating wire of the hollow cathode, which is composed of heat-conducting ceramic (2), heating wire (1), conductive leading-out wire (5), conductive limiting wire (7), and insulating limiting sleeve (6). Figure 1 The hollow cathode emitter (3) and the hollow cathode cathode tube (4) are components of the hollow cathode itself, and their shapes are not limited,Figure 1 The hollow cathode emitter (3) and the hollow cathode tube (4) given in the above are only one of the classic configurations, i.e. the hollow cathode emitter is fixed to the inner top end of the hollow cathode tube. The heat-conducting ceramic is fixed outside the hollow cathode tube, and its axial direction should completely cover the axial direction of the hollow cathode emitter to meet the heating effect. The heating wire is wound in the spiral groove on the heat-conducting ceramic. One end of the heating wire is connected to the cathode tube as the negative electrode of the heating wire, and the other end needs to be connected to the positive electrode as the lead-out end, which is connected to the conductive lead-out wire. The heating wire is tightly wound on the straight section of one of the conductive lead-out wires for several turns. The conductive lead-out wire ring part wound with the heating wire can be clamped at the end of the heat-conducting ceramic. The heating wire is spirally wound around the ring part of the conductive lead-out wire for one turn. The insulating limiting sleeve is sleeved on the straight section of the conductive lead-out wire. The two metal wires of the straight section of the conductive lead-out wire are respectively located on the left and right sides of the conductive limiting wire fin part, pass through the left and right limiting holes of the conductive limiting wire, and the front end of the conductive limiting wire is inserted into the insulating limiting sleeve.

[0010] The conductive lead-out wire (5) is a metal wire with a three-dimensional spatial curve structure, which is divided into a conductive lead-out wire ring part (5-1) and a conductive lead-out wire straight section (5-1). The plane of the conductive lead-out wire ring part is perpendicular to the straight section, and the conductive lead-out wire straight section has two wires. The basic function of the conductive lead-out wire is to conduct electricity and reduce the resistance of the non-heating section. Thanks to its three-dimensional configuration, it can effectively increase the contact length of the heating wire and the conductive lead-out wire without being limited by the length of the hollow cathode, and reduce the contact resistance.

[0011] The conductive limiting wire (7) is a metal wire with three-dimensional spatial curve structure, which is divided into four parts: conductive limiting wire front end (7-1), fin part (7-2), connecting section (7-5), limiting hole (7-3) and conductive limiting wire electricity connection end (7-4). The conductive limiting wire is a whole metal wire, the conductive limiting wire front end is linear, the metal wire is raised behind the conductive limiting wire, and a rectangle with one side missing is formed after three right-angle bends on the plane where the conductive limiting wire front end is located (there are countless planes, and any plane can be used). The structure is the fin part, the limiting hole is behind the fin part, and the connecting section is linear between them, which is on the same straight line with the conductive limiting wire front end in space and used to adjust the distance between them. The limiting hole is located on a plane perpendicular to the conductive limiting wire front end, the metal wire reaches this plane after one right-angle bend, and then bends into an ∞ shape on this plane, and the two circles on the left and right are the limiting holes. The tangent point between the two circles is the starting position of the bend, which is also the end position of the bend. The line between the two centers is perpendicular to the plane where the straight line of the conductive limiting wire front end and the plane of the fin part are located. After one right-angle bend, it can be on the same straight line with the conductive limiting wire front end again. This section is the conductive limiting wire electricity connection end. The basic function of the conductive limiting wire is to conduct electricity, which is due to the three-dimensional structure of the fin part raised on the plane where the conductive limiting wire front end is located and the limiting hole perpendicular to the plane where the conductive limiting wire front end and the fin part are located. This makes it possible to fix the whole lead-out structure.

[0012] The heating wire is tightly wound around the straight section of one of the conductive lead-out wires for several turns, so that the end of the heating wire is connected and fixed with the conductive lead-out wire. The heating wire is spirally wound around the circular ring part of the conductive lead-out wire for one turn, and the tighter the spiral winding is, the better. The three-dimensional configuration of the conductive lead-out wire forms a three-dimensional configuration of the heating wire lead-out, which increases the contact between the heating wire and the lead-out conductive lead-out wire without extending the heating wire and the lead-out conductive lead-out wire connecting section, breaks the one-dimensional restriction of the axial length of the internal space of the hollow cathode, and reduces the contact resistance.

[0013] The inner diameter of the conductive lead-out wire circular ring area is slightly larger than the outer diameter of the heat-conducting ceramic to be matched, so that the circular ring part of the conductive lead-out wire wound with the heating wire can be clamped in the fixed groove at the end of the heat-conducting ceramic. After the insulating limiting sleeve is put on, the circular ring part of the conductive lead-out wire can be tightened so that it is tightly clamped in the fixed groove at the end of the heat-conducting ceramic, completing the fixation of the conductive lead-out wire and the heat-conducting ceramic and strengthening the anti-seismic performance of the structure. The subsequent heating wire part is wound on the heat-conducting ceramic, which ensures that all parts of the heating wire are tightly attached to the surface of the heat-conducting ceramic or the surface of the conductive lead-out wire or both, without any part of the heating wire hanging in the air. In addition, the heating wire has no turning angle that can produce strong stress concentration, so the heat transfer effect of the heating wire is guaranteed, and the service life of the heating wire is also extended.

[0014] The straight section of the conductive lead-out wire is sleeved with an insulating limiting sleeve, and the straight section of the conductive lead-out wire has two roots, which are respectively located on the left and right sides of the conductive limiting wire fin and pass through the left and right limiting holes of the conductive limiting wire, and the front end of the conductive limiting wire is inserted into the insulating limiting sleeve. The fin expands the distance between the conductive lead-out wires, so that they are tightly attached to the inner wall of the insulating limiting sleeve to form a friction force, thereby completing the fixation of the insulating limiting tube; the limiting hole fixes the distance between the two conductive lead-out wires on the fin, so that the two conductive lead-out wires are tightly attached to the fin to form a friction force, thereby completing the fixation of the conductive limiting wire; and the fixation of the conductive lead-out wire and the fixation of the insulating limiting tube also fix the relative position of the conductive lead-out wire and the insulating limiting tube, so that the tightening effect of the insulating limiting tube on the circular ring section of the conductive lead-out wire is more stable, and the connection between the conductive lead-out wire and the heat-conducting ceramic is more stable. Under the stable system of the whole connection, the heating wire wound thereon can avoid fatigue damage due to vibration between structural parts. At the same time, three conductive lead-out wires are led out, the useless resistance is reduced, the anti-vibration performance is strengthened, and the connection misplacement is prevented.

[0015] The insulating limiting sleeve has an elongated cylindrical structure, and the inner diameter is 1.5-1.7 times the diameter of the conductive limiting wire, and the wall thickness of the cylinder is 1-2 mm.

[0016] The heat-conducting ceramic has a cylindrical structure, and has a spiral groove (2-2) for winding the heating wire, and has a circular hole with an axis along the radial direction of the heat-conducting ceramic at one end of the spiral groove, which is a wire passing hole (2-1). There is an annular groove around the outer wall of the heat-conducting ceramic at the other end of the heat-conducting ceramic, which is a fixing groove (2-3).

[0017] The hollow cathode emitter has a cylindrical structure, and the outer diameter is slightly smaller than that of the hollow cathode tube, and the wall thickness is 2-3 mm.

[0018] The hollow cathode tube has a cylindrical structure with a top cover, and the top cover has an opening in the center.

[0019] It is worth noting that the hollow cathode emitter (3) and the hollow cathode tube (4) are components of the hollow cathode itself, and the lead-out structure described in the present application has no requirements and limitations on the shape, and can be matched with various shapes of hollow cathode emitters and hollow cathode tubes, Figure 1 The hollow cathode emitter (3) and the hollow cathode tube (4) given in the present application are only one of the classic configurations, i.e. the hollow cathode emitter is fixed to the inner top end of the hollow cathode tube.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The problem of the suspended part of the heating wire is solved, the instant heating type breakage caused by the deterioration of heat transfer is prevented, the stress concentration of the connecting part of the heating wire is eliminated, the life of the hollow cathode heating wire is prolonged, the contact area of the heating wire and the conductive lead-out wire is increased in the limited space, and the contact resistance is reduced, and the whole lead-out structure has better stability and shock resistance. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a general sectional view of the lead-out structure.

[0023] Figure 2 It is an assembly schematic view of the conductive lead-out wire-conductive limiting wire-insulating limiting sleeve.

[0024] Figure 3 It is a structure view of the conductive lead-out wire.

[0025] Figure 4 It is a partial view of the conductive lead-out wire-heating wire.

[0026] Figure 5 It is a general view of the conductive lead-out wire-heating wire.

[0027] Figure 6 It is a structure view of the conductive limiting wire.

[0028] Figure 7 It is a structure view of the heat-conducting ceramic

[0029] The following is a description of the reference numerals in the drawings:

[0030] 1: heating wire 2: heat-conducting ceramic 3: hollow cathode emitter

[0031] 4: hollow cathode cathode tube 5: conductive lead-out wire 6: insulating limiting sleeve

[0032] 7: conductive limiting wire

[0033] 2-1: wire hole 2-2: spiral groove 2-3: fixing groove

[0034] 5-1: conductive lead-out wire ring part 5-2: conductive lead-out wire straight section

[0035] 7-1: front end of conductive limiting wire 7-2: fin part 7-3: limiting hole

[0036] 7-4: conductive limiting wire power connection end 7-5: connecting section DETAILED DESCRIPTION

[0037] Next, some preferred and secondary schemes used in the application will be given:

[0038] The heating wire often adopts tungsten wire, and can also use rhenium-tungsten wire or nickel-chromium alloy and other common heating wire materials, and the diameter is 0.2-0.4mm. For different heating wire materials, the diameter is generally different. The heating power is equal to the square of the heating current multiplied by the heating wire resistance. The heating wire resistance is determined according to the working current of the power supply under the premise that the heating power meets the hollow cathode ignition condition. The length of the heating wire is directly determined by the heat-conducting ceramic. The length of the heating wire is consistent under the premise of not replacing the heat-conducting ceramic. Then the diameter of the heating wire can be determined.

[0039] The diameter of the conductive lead wire and the conductive limiting wire is 0.5-1mm. Under the premise of meeting the space limitation of the hollow cathode, the thicker the better. The material can also use tantalum and other high-temperature resistant metals.

[0040] The diameter of the conductive lead wire ring part should be slightly larger than the outer diameter of the heat-conducting ceramic, so that it can form an interference fit with the fixing groove of the heat-conducting ceramic after winding the heating wire, and can be clamped on the fixing groove of the heat-conducting ceramic.

[0041] The diameter of the spiral groove of the heat-conducting ceramic should be equal to or slightly larger than the diameter of the heating wire, and the diameter of the wire hole should be slightly larger than the diameter of the heating wire.

[0042] The conductive lead wire is preferably bent from a metal wire. If the process is poor, the second choice is to use welding and other processes to connect several parts together to form a conductive limiting wire.

[0043] The conductive limiting wire has two special structures of fin and limiting hole. The conductive limiting wire can be bent from a metal wire. If the process is poor, the second choice is to use welding and other processes to connect several parts together to form a conductive limiting wire.

[0044] The fin and the limiting hole on the conductive limiting wire should not be too far apart, which is 0.5cm to 1.5cm. If it exceeds 2cm, the fixing friction will be small, and it will be difficult to complete the fixing task, and the overall structure will be loose.

[0045] The insulating limiting sleeve is a slender cylindrical structure, and the inner diameter is 1.5-1.7 times the diameter of the conductive limiting wire, and the cylinder is 1-2mm thick.

[0046] In the following, the implementation form of the structure will be explained from the assembly process:

[0047] The first step is that the heating wire is wound on the straight section of one of the conductive lead-out wires for 5-6 turns, so that the end of the heating wire is connected and fixed with the conductive lead-out wire; the second step is that the heating wire is spirally wound around the circular ring part of the conductive lead-out wire for one turn, and the spiral winding is as thin as possible; the third step is that the conductive lead-out wire circular ring part with the heating wire is clamped in the fixed groove of the heat-conducting ceramic end; the fourth step is that the insulating limiting sleeve is sleeved on the straight section of the conductive lead-out wire, and the circular ring part of the conductive lead-out wire is as tightly clamped in the limiting groove of the heat-conducting ceramic end as possible; the fifth step is that the straight sections of the two conductive lead-out wires are respectively located on the left and right sides of the conductive limiting wire fin part and are respectively passed through the left and right limiting holes of the conductive limiting wire; the sixth step is that the front end of the conductive limiting wire is inserted into the insulating limiting sleeve; the seventh step is that the heating wire is wound on the heat-conducting ceramic; the eighth step is that the heating wire is passed through the wire passing hole, and thus the assembly of the heating ceramic-conductive lead-out wire-conductive limiting wire-insulating limiting sleeve is assembled, and the next step is to install the assembly of the heating ceramic-conductive lead-out wire-conductive limiting wire-insulating limiting sleeve in the hollow cathode. The first step is to fix the heating ceramic in the assembly of the heat-conducting ceramic-conductive lead-out wire-conductive limiting wire-insulating limiting sleeve on the cathode tube, and the two are fixed; the second step is that the end of the heating wire is in contact with the cathode tube of the hollow cathode, which can be welded or wound around the end of the heating wire and the cathode tube of the hollow cathode. Thus, the lead-out structure with small useless resistance, stability, high space utilization and good protection of the heating wire is applied to the hollow cathode.

[0048] It is worth noting that the hollow cathode emitter is a cylindrical structure, and its outer diameter is slightly smaller than that of the hollow cathode cathode tube, and the wall thickness is 2-3 mm. The hollow cathode cathode tube is a cylindrical structure with a top cover, and the top cover has an opening in the center. The hollow cathode emitter (3) and the hollow cathode cathode tube (4) are components of the hollow cathode itself, and the lead-out structure described in the present application has no requirements and limitations on the shape, and can be matched with various shapes of hollow cathode emitters and hollow cathode cathode tubes, Figure 1 The hollow cathode emitter (3) and the hollow cathode cathode tube (4) given in the above are only one of the classic configurations, that is, the hollow cathode emitter is fixed to the inner top end of the hollow cathode cathode tube.

[0049] The above-described embodiments are only descriptions of the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A hollow cathode heating filament three-dimensional extraction structure, characterized in that: The hollow cathode is composed of heat-conducting ceramic, heating wire, conductive lead wire, conductive limiting wire and insulating limiting sleeve. Meanwhile, the hollow cathode itself is composed of hollow cathode emitter and hollow cathode tube, and the shape is not limited. The heat-conducting ceramic is fixed outside the hollow cathode tube, and the axial direction of the heat-conducting ceramic should completely cover the axial direction of the hollow cathode emitter to meet the heating effect. The heating wire is wound in the spiral groove on the heat-conducting ceramic. One end of the heating wire is connected with the hollow cathode tube as the negative electrode of the heating wire, and the other end needs to be connected with the positive electrode as the lead end. The heating wire is wound several turns on the straight section of one of the conductive lead wires. The conductive lead wire with the wound heating wire is clamped at the end of the heat-conducting ceramic. The heating wire is spirally wound around the conductive lead wire ring part for one turn. The insulating limiting sleeve is sleeved on the straight section of the conductive lead wire. The two metal wires of the straight section of the conductive lead wire are respectively located on the left and right sides of the fin part of the conductive limiting wire, pass through the left and right limiting holes of the conductive limiting wire, and the front end of the conductive limiting wire is inserted into the insulating limiting sleeve. The conductive limiting wire is a metal wire with a three-dimensional spatial curve structure, which is divided into a conductive limiting wire front end, a fin part, a connecting section, a limiting hole and a conductive limiting wire electrode end. The conductive limiting wire is a whole metal wire. The conductive limiting wire front end is in a straight line shape. The metal wire rises after the conductive limiting wire front end. After three right-angle bends on the plane where the conductive limiting wire front end is located, a rectangle with one side missing is formed. This structure is the fin part. The limiting hole is located behind the fin part. The connecting section is in a straight line shape in space and is on the same straight line with the conductive limiting wire front end, used for adjusting the distance between them. The limiting hole is located on a plane perpendicular to the conductive limiting wire front end. The metal wire comes to this plane after one right-angle bend. Then the metal wire is bent into an ∞ shape on this plane. The left and right two circles are the limiting holes. The tangent point between the two circles is the bending start position and also the bending end position. The connecting line between the two centers is perpendicular to the plane where the straight line of the conductive limiting wire front end and the plane where the fin part are located. After one right-angle bend, the connecting line is again on the same straight line with the conductive limiting wire front end. This section is the conductive limiting wire electrode end.

2. The hollow cathode heating filament three-dimensional extraction structure according to claim 1, characterized in that: The hollow cathode emitter is fixed inside the top end of the hollow cathode tube. The hollow cathode emitter is a cylindrical structure with an outer diameter smaller than the hollow cathode tube. The hollow cathode tube is a cylindrical structure with a top cover having an opening in the center.

3. The hollow cathode heating filament three-dimensional extraction structure according to claim 1, wherein: The conductive lead wire is a metal wire with a three-dimensional spatial curve structure, which is divided into a conductive lead wire ring part and a conductive lead wire straight section. The plane where the conductive lead wire ring part is located is perpendicular to the straight section. The conductive lead wire straight section has two metal wires.

4. The hollow cathode heating filament three-dimensional extraction structure of claim 1, wherein: The heating wire is wound on the straight section of one of the conductive lead wires for several turns, so that the end of the heating wire is connected and fixed with the conductive lead wire; the heating wire is spirally wound around the circular ring part of the conductive lead wire for one turn, and the spiral winding is better, and the three-dimensional structure of the heating wire is formed by the three-dimensional structure of the conductive lead wire, which can increase the contact between the heating wire and the conductive lead wire without extending the connection section of the heating wire and the conductive lead wire, and reduce the contact resistance.

5. The hollow cathode heating filament three-dimensional extraction structure according to claim 1 or 3, characterized in that: The inner diameter of the conductive lead wire circular ring area is larger than the outer diameter of the heat-conducting ceramic to be matched, so that the conductive lead wire circular ring part wound with the heating wire is clamped in the fixed groove at the end of the heat-conducting ceramic, and the conductive lead wire circular ring part is tightened after the insulating limiting sleeve is sleeved, so that it is tightly clamped in the fixed groove at the end of the heat-conducting ceramic, the fixation of the conductive lead wire and the heat-conducting ceramic is completed, and the anti-seismic performance of the structure is strengthened.

6. The hollow cathode heating filament three-dimensional extraction structure according to claim 5, characterized in that: The conductive lead wire straight section is sleeved with an insulating limiting sleeve, and the conductive lead wire straight section has two metal wires, which are respectively located on the left and right sides of the conductive limiting wire fin part and pass through the left and right limiting holes of the conductive limiting wire, and the front end of the conductive limiting wire is inserted into the insulating limiting sleeve; the fin part expands the distance between the conductive lead wires, so that they are tightly attached to the inner wall of the insulating limiting sleeve to form friction, and the fixation of the insulating limiting sleeve is completed; the limiting holes fix the distance between the two conductive lead wires on the fin part, so that the two conductive lead wires are tightly attached to the fin part to form friction, and the fixation of the conductive limiting wire is completed; the fixation of the conductive lead wire and the fixation of the insulating limiting sleeve also fix the relative position of the conductive lead wire and the insulating limiting sleeve, so that the tightening effect of the insulating limiting sleeve on the conductive lead wire circular ring area is more stable, and the connection between the conductive lead wire and the heat-conducting ceramic is more stable.

7. The hollow cathode heating filament three-dimensional extraction structure of claim 1, wherein: The insulating limiting sleeve is a slender cylindrical structure, and its inner diameter is 1.5-1.7 times the diameter of the conductive limiting wire.

8. The hollow cathode heating filament three-dimensional extraction structure of claim 1, wherein: The heat-conducting ceramic is a cylindrical structure, and has a spiral groove for winding the heating wire, and a circular hole with an axis along the radial direction of the heat-conducting ceramic at one end of the spiral groove as a wire passing hole; the other end of the heat-conducting ceramic has an annular groove around the outer wall of the heat-conducting ceramic as a fixed groove.

9. A method for implementing the hollow cathode heating filament three-dimensional extraction structure according to claim 1, characterized in that: Firstly, the heat-conducting ceramic-conductive lead wire-conductive limiting wire-insulating limiting sleeve assembly needs to be assembled, specifically as follows: First step: winding the heating wire on the straight section of one of the conductive lead wires for 5-6 turns, so that the end of the heating wire is connected and fixed with the conductive lead wire; Second step: spirally winding the heating wire around the circular ring part of the conductive lead wire for one turn in the conductive lead wire circular ring area, and the spiral winding is fine; Third step: clamping the conductive lead wire circular ring area wound with the heating wire in the fixed groove at the end of the heat-conducting ceramic; Fourth step: sleeving the insulating limiting sleeve on the conductive lead wire straight section, and tightening the conductive lead wire circular ring part so that it is tightly clamped in the fixed groove at the end of the heat-conducting ceramic; Fifth step: placing the two metal wires of the conductive lead wire straight section on the left and right sides of the fin part of the conductive limiting wire respectively and passing through the left and right limiting holes of the conductive limiting wire; Sixth step: inserting the front end of the conductive limiting wire into the insulating limiting sleeve; Seventh step: winding the heating wire on the heat-conducting ceramic; Eighth step: passing the heating wire through the wire passing hole, and the assembly is completed. Then the heat-conducting ceramic-conductive lead-out wire-conductive limiting wire-insulating limiting sleeve assembly is installed in the hollow cathode; Specifically: Step one: the heat-conducting ceramic in the heat-conducting ceramic-conductive lead-out wire-conductive limiting wire-insulating limiting sleeve assembly is fixed on the cathode tube, and the two are fixed; Step two: the end of the heating wire is in contact with the cathode tube of the hollow cathode, and the welding method or the winding method of the end of the heating wire and the cathode tube of the hollow cathode is adopted.

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