Electron Gun

Abstract

This invention discloses an electron gun, comprising a cooling assembly and a cathode assembly. The cooling assembly includes a bottle, silicone oil, and a liquid cooling pipe. The bottle has a receiving cavity in which the silicone oil is contained. The liquid cooling pipe is disposed on the bottle and located within the receiving cavity, and the liquid cooling pipe cools the silicone oil. The cathode assembly includes a cathode cup and a filament. The filament is disposed in the cathode cup, which is connected to the bottle. The cooling assembly of this invention utilizes the liquid cooling pipe to lower the temperature of the silicone oil, thereby lowering the temperature of the bottle. Because the cathode cup in the cathode assembly is connected to the bottle, it indirectly cools the cathode cup, ultimately effectively controlling the temperature of the filament disposed in the cathode cup. This prevents the filament from overheating and deforming, ensuring the printing accuracy of the electron gun and the lifespan of the filament.

Description

Technical Field

[0001] The present invention relates to the technical field of precision additive manufacturing, and in particular to an electron gun. Background Art

[0002] Metal 3D printing is a high-end manufacturing technology that achieves part processing by layer-by-layer material accumulation. It is widely used in aerospace, automotive, mold, medical and other fields, especially in medical implants and industrial high-performance parts. At present, metal 3D printing technology is divided into laser 3D printing and electron beam 3D printing according to different heat sources. Compared with laser 3D printing technology, electron beam 3D printing technology has the advantages of better preheating effect, better mechanical properties and surface quality of formed parts due to its higher output power and scanning speed.

[0003] The electron gun includes an emitter (cathode) for generating electrons and an extraction electrode (anode) for accelerating electrons. In an electron gun, a tungsten wire is generally used as the cathode. When the tungsten wire is energized and heated, a large number of hot electrons are generated on the surface. Under the action of the high-voltage electric field between the anode and the cathode, the hot electrons are accelerated to move toward the anode at high speed and obtain very high kinetic energy. When the electron gun is working, the temperature of the cathode is relatively high. If it works at high temperature for a long time, the cathode will deform, affecting the emission density of the electron beam. At the same time, the electron beam will diverge seriously, causing the beam spot to become larger, affecting the printing accuracy. Summary of the invention

[0004] The object of the present invention is to provide an electron gun which can prevent the cathode temperature from being too high.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] An electron gun is provided, comprising:

[0007] A cooling assembly, the cooling assembly comprising a bottle body, silicone oil and a liquid cooling pipe, wherein a receiving cavity is provided in the bottle body, the silicone oil is contained in the receiving cavity, the liquid cooling pipe is arranged on the bottle body and located in the receiving cavity, and the liquid cooling pipe can cool the silicone oil;

[0008] The cathode assembly comprises a cathode cup and a filament, wherein the filament is arranged in the cathode cup, and the cathode cup is connected to the bottle body.

[0009] As a preferred solution of the present invention, the bottle body includes a high-pressure porcelain bottle, a ring and an upper cover, the ring is sleeved on the outer surface of the high-pressure porcelain bottle, the upper cover is detachably connected to the top of the ring, and the liquid cooling pipe is arranged on the upper cover.

[0010] As a preferred solution of the present invention, the liquid cooling tube is U-shaped, the high-pressure porcelain bottle is truncated cone-shaped, a truncated cone-shaped cavity is provided in the ring, the large end of the high-pressure porcelain bottle is arranged in the cavity, and the small end of the high-pressure porcelain bottle is connected to the cathode cup.

[0011] As a preferred embodiment of the present invention, the electron gun further comprises an anode assembly, wherein the anode assembly is spaced apart from the cathode assembly, the anode assembly is arranged on a side of the cathode assembly away from the cooling assembly, the anode assembly comprises an anode body and a cooling ring, the cooling ring surrounds the anode body, a flow channel for the flow of a coolant is provided in the cooling ring, and the flow channel forms a coolant inlet and a coolant outlet on the surface of the cooling ring.

[0012] As a preferred solution of the present invention, an electron channel is provided on the anode body, and the electron channel runs through the anode body.

[0013] As a preferred solution of the present invention, the electron gun further comprises a correction device, and the correction device is arranged on a side of the anode assembly away from the cathode assembly.

[0014] As a preferred solution of the present invention, the electron gun further comprises a beam guide tube, which is arranged on a side of the correction device away from the anode assembly, the center line of the electron channel coincides with the center line of the beam guide tube, and the inner wall of the beam guide tube is coated with graphite.

[0015] As a preferred solution of the present invention, the electron gun further comprises a focusing coil, and the focusing coil is arranged around the beam guide tube.

[0016] As a preferred solution of the present invention, the electron gun further comprises a deflection coil, wherein the deflection coil is arranged around the beam guide tube, and the focusing coil is arranged between the correction device and the deflection coil.

[0017] As a preferred solution of the present invention, the filament is a tungsten filament, and the filament is V-shaped.

[0018] Beneficial effects of the present invention:

[0019] The cooling assembly of the electron gun of the present invention can use a liquid cooling tube to reduce the temperature of the silicone oil, thereby reducing the temperature of the bottle body. Since the cathode cup in the cathode assembly is connected to the bottle body, the cathode cup is indirectly cooled, and finally the temperature of the filament arranged in the cathode cup is also effectively controlled, thereby avoiding deformation of the filament due to excessive temperature, and ensuring the printing accuracy of the electron gun and the service life of the filament. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of an electron gun according to a first embodiment of the present invention;

[0021] Figure 2 for Figure 1 A cross-sectional view of a cooling assembly;

[0022] Figure 3 for Figure 1 A schematic diagram of the structure of the cathode assembly;

[0023] Figure 4 for Figure 1 Exploded perspective view of the anode assembly.

[0024] In the figure:

[0025] 1. Cooling assembly; 11. Bottle body; 111. High-pressure porcelain bottle; 112. Ring; 113. Upper cover; 12. Silicone oil; 13. Liquid cooling tube; 2. Cathode assembly; 21. Cathode cup; 211. Emitting hole; 22. Filament; 3. Anode assembly; 31. Anode body; 311. Electron channel; 32. Cooling ring; 321. Coolant inlet; 322. Coolant outlet; 4. Correction device; 5. Beam guide tube; 6. Focusing coil; 61. Primary focusing coil; 62. Secondary focusing coil; 7. Deflection coil; 100. Accommodating cavity. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0029] like Figures 1 to 3 As shown, an electron gun according to an embodiment of the present invention comprises a cooling assembly 1 and a cathode assembly 2. The cooling assembly 1 comprises a bottle body 11, silicone oil 12 and a liquid cooling tube 13. A receiving cavity 100 is provided in the bottle body 11. The silicone oil 12 is contained in the receiving cavity 100. The liquid cooling tube 13 is arranged on the bottle body 11 and located in the receiving cavity 100. The liquid cooling tube 13 can cool the silicone oil 12. The cathode assembly 2 comprises a cathode cup 21 and a filament 22. The filament 22 is arranged in the cathode cup 21, and the cathode cup 21 is connected to the bottle body 11.

[0030] The cooling assembly 1 of the electron gun of this embodiment can use the liquid cooling tube 13 to reduce the temperature of the silicone oil 12, thereby reducing the temperature of the bottle body 11. Since the cathode cup 21 in the cathode assembly 2 is connected to the bottle body 11, the cathode cup 21 is indirectly cooled, and finally the temperature of the filament 22 arranged in the cathode cup 21 is also effectively controlled, so as to avoid the deformation of the filament 22 due to excessive temperature, and ensure the printing accuracy of the electron gun and the service life of the filament 22. Water or other types of solutions can be passed into the liquid cooling tube 13 as a coolant.

[0031] The filament 22 is preferably a tungsten filament. Tungsten has a high melting point and strong corrosion resistance, so it has a long service life, and the cost of tungsten filament is relatively low. In this embodiment, the shape of the filament 22 is V-shaped, and an emission hole 211 is opened at the bottom of the cathode cup 21. The tip of the filament 22 is directly opposite to the emission hole 211, and the electron beam is emitted from the emission hole 211. The initial electron beam formed by the filament 22 of this shape has a high emission density, and the divergence of the electron beam is small, and the beam spot diameter is small, so it has a high precision.

[0032] Further, the bottle body 11 includes a high-voltage porcelain bottle 111, a collar 112 and an upper cover 113. The collar 112 is sleeved on the outer surface of the high-voltage porcelain bottle 111. The upper cover 113 is detachably connected to the top of the collar 112, and the liquid cooling tube 13 is arranged on the upper cover 113. When it is at room temperature, the volume of the silicone oil 12 is smaller than the volume of the accommodating cavity 100. Because the silicone oil 12 will expand after being heated, a certain space should be reserved to avoid the expanded silicone oil 12 exerting excessive pressure on the bottle body 11 and causing structural damage to the bottle body 11. Therefore, when it is at room temperature, the silicone oil 12 can not immerse the liquid cooling tube 13. When the electron gun is working, the silicone oil 12 expands due to heat, and the liquid cooling tube 13 contacts the silicone oil 12, so that the silicone oil 12 can be cooled. Since the upper cover 113 is detachably connected to the top of the collar 112, when the silicone oil 12 needs to be replaced, the upper cover 113 can be opened to operate.

[0033] Furthermore, the liquid cooling tube 13 is U-shaped, the high-pressure porcelain bottle 111 is truncated, a truncated cavity is provided in the collar 112, the large end of the high-pressure porcelain bottle 111 is arranged in the cavity, and the small end of the high-pressure porcelain bottle 111 is connected to the cathode cup 21. The high-pressure porcelain bottle 111 has good insulation, and the silicone oil 12 also has good insulation, so a good insulation effect can be achieved. The outer surface of the large end of the high-pressure porcelain bottle 111 fits with the inner surface of the collar 112, has good sealing, can prevent the silicone oil 12 from flowing out, and the truncated cavity of the collar 112 can limit the high-pressure porcelain bottle 111, which is convenient for assembly between the high-pressure porcelain bottle 111 and the collar 112. When the high-pressure porcelain bottle 111 and the collar 112 need to be assembled, the small end of the high-pressure porcelain bottle 111 is first passed through the collar 112. As the high-pressure porcelain bottle 111 moves, the outer wall of the large end of the high-pressure porcelain bottle 111 will fit with the inner wall of the collar 112.

[0034] When the silicone oil 12 expands due to heat, the assembly of the high-pressure porcelain bottle 111 and the sleeve ring 112 allows the pressure generated by the silicone oil 12 to fit the outer wall of the high-pressure porcelain bottle 111 and the inner wall of the sleeve ring 112 more closely together, and the silicone oil 12 will not leak. Of course, the volume of the silicone oil 12 needs to be calculated so that even if the silicone oil 12 expands to the maximum extent, it will only generate a small pressure and will not damage the bottle body 11.

[0035] The high-pressure porcelain bottle 111 and the sleeve ring 112 can be bonded with an adhesive or other connection methods. In this embodiment, the liquid cooling tube 13 is U-shaped, and the liquid cooling tube 13 is preferably made of brass, so that the liquid cooling tube 13 has a higher thermal conductivity and can have a better cooling effect on the silicone oil 12. In other embodiments, the liquid cooling tube 13 is twisted into a spiral shape, so that the liquid cooling tube 13 and the silicone oil 12 have a larger contact area, thereby improving the cooling effect.

[0036] like Figure 1 and Figure 4 As shown, the electron gun of this embodiment further includes an anode assembly 3, which is spaced apart from the cathode assembly 2. The anode assembly 3 is arranged on the side of the cathode assembly 2 away from the cooling assembly 1. The anode assembly 3 includes an anode body 31 and a cooling ring 32. The cooling ring 32 surrounds the anode body 31. A flow channel for the flow of coolant is provided in the cooling ring 32. The flow channel forms a coolant inlet 321 and a coolant outlet 322 on the surface of the cooling ring 32. A high-voltage electric field can be generated between the anode assembly 3 and the cathode assembly 2. This high-voltage electric field causes the electrons emitted from the emission hole 211 to move at high speed. Not only will the cathode assembly 2 have a problem of over-temperature when the electron gun is working, but the anode assembly 3 will also face the problem of over-temperature. Once the temperature of the anode assembly 3 is too high, it will also cause it to deform, so that its function cannot be performed normally. In this embodiment, the cooling ring 32 can be passed with coolant, so that the temperature of the cooling ring 32 is effectively controlled, and the anode body 31 is also connected to the cooling ring 32, so that the temperature of the anode body 31 is not too high.

[0037] Furthermore, an electron channel 311 is provided on the anode body 31, and the electron channel 311 runs through the anode body 31. The electrons emitted from the emission hole 211 will pass through the electron channel 311 at high speed, so the electron channel 311 must be aligned with the emission hole 211. When the temperature of the anode body 31 is too high, the electron channel 311 may be deformed, resulting in the electrons being unable to pass smoothly and directly hitting the anode body 31. These electrons hitting the anode body 31 will cause the temperature of the anode body 31 to further increase. Therefore, the temperature of the anode body 31 must be controlled.

[0038] like Figure 1 As shown, the electron gun of this embodiment also includes a correction device 4, which is arranged on the side of the anode assembly 3 away from the cathode assembly 2. The correction device 4 includes a shell and a correction coil, which is arranged inside the shell. The correction coil can make a preliminary correction to the electron beam emitted through the electron channel 311 and has a focusing effect on the electron beam. The outer surface of the shell is coated with graphite, and the coated graphite has a conductive effect and can eliminate the influence of static electricity. The shell is provided with small holes on the upper and lower sides, and the electron beam passing through the anode assembly 3 is ejected from the small holes.

[0039] like Figure 1 As shown, the electron gun of this embodiment further includes a beam guide tube 5, which is arranged on the side of the correction device 4 away from the anode assembly 3, the center line of the electron channel 311 coincides with the center line of the beam guide tube 5, and the inner wall of the beam guide tube 5 is coated with graphite. After the electron beam passes through the correction device 4, it will enter the beam guide tube 5, and the graphite-coated beam guide tube 5 can eliminate static electricity, avoid static electricity from interfering with the electron beam, and improve the beam quality of the electron beam.

[0040] like Figure 1 As shown, the electron gun of this embodiment further includes a focusing coil 6, which is arranged around the beam guide tube 5. The focusing coil 6 includes a main focusing coil 61 and a secondary focusing coil 62, both of which are in annular shape, and the main focusing coil 61 is sleeved outside the secondary focusing coil 62. After the electron beam enters the focusing coil 6, the focusing coil 6 focuses the accelerated electron beam to reduce the diameter of the beam spot.

[0041] like Figure 1 As shown, the electron gun of this embodiment further includes a deflection coil 7, which is arranged around the beam guide tube 5, and a focusing coil 6 is arranged between the correction device 4 and the deflection coil 7. The deflection coil 7 deflects the focused electron beam, corrects the focusing angle of the electron beam, makes it accurately hit the part, improves the printing accuracy, and thus improves the quality of the printed part.

[0042] As a preferred embodiment of the present invention, in the description of this specification, the reference term "further" or the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0043] The above embodiments are only used to illustrate the detailed scheme of the present invention, and the present invention is not limited to the above detailed scheme, that is, it does not mean that the present invention must rely on the above detailed scheme to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An electron gun, characterized in that: include: A cooling assembly, the cooling assembly comprising a bottle body, silicone oil and a liquid cooling pipe, wherein a receiving cavity is provided in the bottle body, the silicone oil is contained in the receiving cavity, the liquid cooling pipe is arranged on the bottle body and located in the receiving cavity, and the liquid cooling pipe can cool the silicone oil; A cathode assembly, the cathode assembly comprising a cathode cup and a filament, the filament being arranged in the cathode cup, and the cathode cup being connected to the bottle body; When in a normal temperature state, the volume of the silicone oil is smaller than the volume of the accommodating cavity, and the silicone oil does not immerse the liquid cooling tube; when the electron gun is working, the silicone oil expands due to heat, and the liquid cooling tube comes into contact with the silicone oil to cool the silicone oil, thereby reducing the temperature of the bottle body. Since the cathode cup in the cathode assembly is connected to the bottle body, the cathode cup is indirectly cooled, and finally the temperature of the filament arranged in the cathode cup is also effectively controlled, thereby preventing the filament from being deformed due to excessive temperature; The filament is a tungsten filament, and the filament is V-shaped.

2. The electron gun according to claim 1, characterized in that The bottle body comprises a high-pressure porcelain bottle, a sleeve ring and an upper cover, wherein the sleeve ring is sleeved on the outer surface of the high-pressure porcelain bottle, the upper cover is detachably connected to the top of the sleeve ring, and the liquid cooling pipe is arranged on the upper cover.

3. The electron gun according to claim 2, characterized in that The liquid cooling tube is U-shaped, the high-pressure porcelain bottle is truncated cone-shaped, a truncated cone-shaped cavity is provided in the sleeve ring, the large end of the high-pressure porcelain bottle is arranged in the cavity, and the small end of the high-pressure porcelain bottle is connected to the cathode cup.

4. The electron gun according to claim 1, characterized in that It also includes an anode assembly, which is spaced apart from the cathode assembly, and is arranged on a side of the cathode assembly away from the cooling assembly. The anode assembly includes an anode body and a cooling ring, which surrounds the anode body, and a flow channel for the flow of coolant is opened in the cooling ring, and the flow channel forms a coolant inlet and a coolant outlet on the surface of the cooling ring.

5. The electron gun according to claim 4, characterized in that An electron channel is provided on the anode body, and the electron channel runs through the anode body.

6. The electron gun according to claim 5, characterized in that The device also includes a correction device, which is arranged on a side of the anode assembly facing away from the cathode assembly.

7. The electron gun according to claim 6, characterized in that It also includes a guide tube, which is arranged on a side of the correction device away from the anode assembly, the center line of the electron channel coincides with the center line of the guide tube, and the inner wall of the guide tube is coated with graphite.

8. The electron gun according to claim 7, characterized in that It also includes a focusing coil, which is arranged around the beam guide tube.

9. The electron gun according to claim 8, characterized in that It also includes a deflection coil, which is arranged around the beam guide tube, and the focusing coil is arranged between the correction device and the deflection coil.

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