Cathode assembly for X-ray tube and X-ray tube

Abstract

A cathode assembly for an X-ray tube and an X-ray tube, wherein the cathode assembly comprises: a cable fixing portion for fixing a cable, the cable fixing portion having a first end and a second end opposite to each other, the first end facing a vacuum region, and the cable comprising at least a high-voltage cable core; an electron emitting portion, the electron emitting portion comprising a head and a connecting tube, the connecting tube being sleeved at the first end and being suitable for enclosing an accommodating space, the head and the first end respectively sealing the two ends of the connecting tube; at least one filament being arranged at a side of the head away from the connecting tube, the filament being used for emitting electrons; a high-voltage pin being at least partially arranged in the accommodating space and having a third end and a fourth end opposite to each other, the third end being coupled to at least one filament, the fourth end passing through the first end and being coupled to the high-voltage cable core; a connecting portion for electrically connecting the connecting tube and the high-voltage pin; wherein the connecting tube sleeve extends toward the second end to beyond the fourth end. Thus, the safety, stability and reliability of the cathode assembly and the X-ray tube can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of X-ray tubes, and in particular to a cathode assembly for an X-ray tube and the X-ray tube. Background Art

[0002] The X-ray tube (also called X-ray tube or CT tube) is the core component of the CT system, which mainly consists of two parts: the cathode assembly and the anode assembly. During the operation of the X-ray tube, a current is loaded on the cathode filament to heat it to produce a large number of electrons, and a high voltage is applied between the cathode and the cathode. Under the action of the strong electric field, the active electrons bombard the anode target plate at high speed from the cathode to generate X-rays. In other words, in the process of generating X-rays, the high-voltage power supply provides filament current to emit electrons on the one hand, and provides a high-voltage electric field to accelerate the electrons on the other hand. Therefore, the high-voltage power supply is connected to the outside of the cathode vacuum of the X-ray tube through a high-voltage cable, and the high-voltage power supply signal needs to be transmitted to the inside of the cathode vacuum of the X-ray tube through a high-voltage connection system. Therefore, the high-voltage connection system must not only play the role of electrical connection, but also have good insulation performance and be able to maintain vacuum.

[0003] However, the existing X-ray tubes have uneven electric field distribution, which leads to excessive local electric field strength and electric field concentration. This electric field concentration phenomenon is prone to sparking and flashover, which may not only damage the equipment but also pose a safety threat to the operator. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a cathode assembly for an X-ray tube and an X-ray tube which is safer and more reliable.

[0005] To solve the above technical problems, an embodiment of the present invention provides a cathode assembly for an X-ray tube, comprising: a cable fixing portion for fixing a cable, the cable fixing portion having a first end and a second end opposite to each other, the first end facing a vacuum region, the second end facing a non-vacuum region, the cable comprising at least a high-voltage cable core; an electron emitting portion, the electron emitting portion comprising a head and a connecting tube, the connecting tube being sleeved on the first end and suitable for enclosing an accommodating space, the head and the first end respectively closing the two ends of the connecting tube; at least one filament being arranged on a side of the head away from the connecting tube, the filament being used to emit electrons; a high-voltage pin being at least partially arranged in the accommodating space and having a third end and a fourth end opposite to each other, the third end being coupled to the at least one filament, the fourth end passing through the first end and being coupled to the high-voltage cable core; a connecting portion for electrically connecting the connecting tube and the high-voltage pin; wherein the portion of the connecting tube sleeved on the first end at least extends toward the second end to beyond the fourth end.

[0006] Optionally, the connecting tube is made of a conductive material, the electric potential at each location of the connecting tube is the same, and an electric field between the cable fixing portion and the electron emitting portion is formed at the periphery of the connecting tube during operation of the X-ray tube.

[0007] Optionally, the cathode assembly also includes: a plurality of filament pins, corresponding to the at least one filament, wherein every two of the filament pins are respectively connected to the two ends of the corresponding filament to supply power to the filament, at least a portion of the filament pins is accommodated in the accommodating space, and the high-voltage pin reuses at least one of the plurality of filament pins.

[0008] Optionally, a window portion is opened on the wall of the connecting tube, and the window portion at least partially exposes the high-voltage pin and the connecting portion accommodated in the accommodating space.

[0009] Optionally, the cable further includes: a low-voltage cable core, both ends of each of the at least one filament being electrically connected to the low-voltage cable core, respectively, and the low-voltage cable core being used to input low-voltage electricity to the filament to heat the filament to generate electrons.

[0010] Optionally, the high-voltage cable core and the low-voltage cable core are insulated from each other and arranged in the cable, and the outer circumference of the high-voltage cable core and the outer circumference of the low-voltage cable core are respectively covered with insulating layers, and the cable fixing part fixes the cable by fixing the insulating layers.

[0011] Optionally, the high-voltage pin includes a first needle portion and a second needle portion that are directly or indirectly electrically connected, wherein the third end is formed on the first needle portion, the fourth end is formed on the second needle portion, and the second needle portion passes through the first end and is connected to the cable.

[0012] Optionally, the connecting portion electrically connects the second needle portion and the connecting cylinder.

[0013] Optionally, the first end is provided with a plurality of mounting through holes, and the number of the second needle parts is multiple, and the plurality of mounting through holes corresponds one-to-one to the plurality of second needle parts, wherein each second needle part passes through the first end from the corresponding mounting through hole, and the inner wall of the mounting through hole is in contact with the outer peripheral surface of the corresponding second needle part.

[0014] Optionally, the second needle portion includes a first section and a second section, wherein at least a portion of the first section extends out of the mounting through hole and is inserted into the accommodating space, and the second section is located in the mounting through hole, and on a plane perpendicular to the extension direction of the second needle portion, a cross-sectional area of ​​the second section is greater than a cross-sectional area of ​​the first section.

[0015] Optionally, the cathode assembly further includes: a sealing gasket located on a surface of the cable fixing portion facing the filament, the sealing gasket being sleeved on the second needle portion to seal a gap between the second needle portion and the mounting through hole.

[0016] Optionally, at the connection between the fourth end and the high-voltage cable core, on a plane perpendicular to the first direction, the cross-sectional area of ​​the high-voltage cable core is equal to the cross-sectional area of ​​the high-voltage pin, wherein the first direction is parallel to the direction from the second end to the first end.

[0017] Optionally, the cathode assembly further includes: a protrusion, which is arranged on one of the high-voltage cable core and the high-voltage pin and protrudes toward the other one; and a recess, which is arranged on the other one of the high-voltage cable core and the high-voltage pin to receive the protrusion.

[0018] Optionally, the high-voltage cable core includes: a needle for electrically connecting to the fourth end; a needle tube having an accommodating cavity extending along a first direction, at least a portion of the needle being accommodated in the accommodating cavity and being able to reciprocate along the first direction; and an elastic mechanism disposed in the accommodating cavity, the elastic mechanism being used to hold the needle against the fourth end.

[0019] Optionally, the cable fixing comprises: a cover portion, suitable for forming the first end; a sleeve portion, connected to the cover portion, the sleeve portion being provided with an assembly hole extending in a direction from the second end to the first end, at least a portion of the cable being accommodated in the assembly hole, the outer peripheral surface of the cable being in contact with the inner wall of the assembly hole, and the end surface of the cable facing the first end being in contact with the cover portion.

[0020] Optionally, the cover portion and the sleeve portion are integrally formed.

[0021] Optionally, the cover portion and the sleeve portion are both made of insulating material.

[0022] Optionally, the sleeve portion and the cover portion are made of the same material.

[0023] To solve the above technical problems, an embodiment of the present invention further provides an X-ray tube, comprising: the above-mentioned cathode assembly; an anode assembly, used to receive electrons emitted by the cathode assembly to generate X-rays; and a housing having a vacuum chamber, wherein the anode assembly and at least a portion of the cathode assembly are located in the vacuum chamber.

[0024] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0025] To solve the above technical problems, an embodiment of the present invention provides a cathode assembly for an X-ray tube, comprising: a cable fixing portion for fixing a cable, the cable fixing portion having a first end and a second end opposite to each other, the first end facing a vacuum region, the second end facing a non-vacuum region, the cable comprising at least a high-voltage cable core; an electron emitting portion, the electron emitting portion comprising a head and a connecting tube, the connecting tube being sleeved on the first end and suitable for enclosing an accommodating space, the head and the first end respectively closing the two ends of the connecting tube; at least one filament being arranged on a side of the head away from the connecting tube, the filament being used to emit electrons; a high-voltage pin being at least partially arranged in the accommodating space and having a third end and a fourth end opposite to each other, the third end being coupled to the at least one filament, the fourth end passing through the first end and being coupled to the high-voltage cable core; a connecting portion for electrically connecting the connecting tube and the high-voltage pin; wherein the portion of the connecting tube sleeved on the first end at least extends toward the second end to beyond the fourth end.

[0026] By adopting the technical solution of the embodiment of the present invention, the high-voltage pin is electrically connected to the connecting tube, so that the electric field distribution can be made more uniform, and the electric field can be effectively prevented from gathering at the connection between the high-voltage pin and the high-voltage cable core to cause discharge or flashover, thereby improving the safety, stability and reliability of the use of the X-ray tube.

[0027] Furthermore, the cross-sectional area of ​​the high-voltage cable core is equal to the cross-sectional area of ​​the high-voltage pin. Pure contact power conduction can be used to avoid the presence of air at the connection, which causes the electric field to gather at the contact position between the metal, the insulating material and the air, thereby generating electric field distortion, causing intrinsic breakdown or surface flashover of the insulating material. These insulation destruction phenomena will damage the X-ray tube and affect the service life of the X-ray tube. At the same time, the electric field at the electrical connection can be made more uniform.

[0028] Furthermore, the electrical connection between the high-voltage cable core and the high-voltage pin is achieved through the cooperation of the protrusion and the recess, and the contact area is increased, which can effectively reduce the contact resistance and reduce the risk of power failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of an X-ray tube according to an embodiment of the present invention;

[0030] Figure 2 yes Figure 1 Section view along AA perspective;

[0031] Figure 3 yes Figure 2 A partial enlarged view of the middle area B;

[0032] Figure 4 yes Figure 3Schematic diagram of the cable fixing part;

[0033] Figure 5 yes Figure 3 A partial enlarged view of the middle area C;

[0034] Figure 6 yes Figure 2 Schematic diagram of the electron emission section;

[0035] Figure 7 is a partial exploded view of a cathode assembly according to an embodiment of the present invention;

[0036] Figure 8 yes Figure 5 Exploded view of the second needle and high-voltage cable core. DETAILED DESCRIPTION

[0037] As mentioned in the background art, existing X-ray tubes have potential safety hazards caused by uneven electric field distribution, and their stability and reliability in use are low.

[0038] To solve the above technical problems, an embodiment of the present invention provides a cathode assembly for an X-ray tube, comprising: a cable fixing portion for fixing a cable, the cable fixing portion having a first end and a second end opposite to each other, the first end facing a vacuum region, the second end facing a non-vacuum region, the cable comprising at least a high-voltage cable core; an electron emitting portion, the electron emitting portion comprising a head and a connecting tube, the connecting tube being sleeved on the first end and suitable for enclosing an accommodating space, the head and the first end respectively closing the two ends of the connecting tube; at least one filament being arranged on a side of the head away from the connecting tube, the filament being used to emit electrons; a high-voltage pin being at least partially arranged in the accommodating space and having a third end and a fourth end opposite to each other, the third end being coupled to the at least one filament, the fourth end passing through the first end and being coupled to the high-voltage cable core; a connecting portion for electrically connecting the connecting tube and the high-voltage pin; wherein the portion of the connecting tube sleeved on the first end at least extends toward the second end to beyond the fourth end.

[0039] By adopting the technical solution of the embodiment of the present invention, by electrically connecting the high-voltage pin to the connecting tube, the electric field distribution can be made more uniform, effectively avoiding the electric field gathering at the connection between the high-voltage pin and the high-voltage cable core to cause discharge or flashover, etc. Thus, the safety, stability and reliability of the use of the X-ray tube can be improved.

[0040] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0041] Figure 1 FIG. 2 is a schematic diagram of an X-ray tube 200 according to an embodiment of the present invention.

[0042] refer to Figure 1 The X-ray tube 200 may include: a cathode assembly 100 for emitting electrons; an anode assembly 201 for receiving electrons emitted by the cathode assembly 100 to generate X-rays; and a housing 202 having a vacuum chamber 2021, wherein the anode assembly 201 and at least a portion of the cathode assembly 100 are located in the vacuum chamber.

[0043] The X-ray tube 200 (also called an X-ray tube or a CT tube) can be used in X-ray machines in the medical field, such as disease detection instruments such as CT machines. With the development of technology, CT machines have been popularized with high resolution and intuitive and accurate diagnostic effects, and have been widely used in the medical field. The X-ray tube 200 can be used as a core component in a CT machine and is widely used to generate X-rays in practice. Therefore, whether the technology of the X-ray tube 200 is perfect directly affects the working effect of the CT machine.

[0044] In the X-ray tube 200, the principle of generating X-rays is that the filament in the cathode assembly 100 generates heat to generate electrons. A large number of electrons are accelerated by the high-voltage electric field between the cathode assembly 100 and the anode assembly 201 to bombard the anode target disk in the anode assembly 201, thereby generating X-rays. The X-rays are reflected by the target surface and emitted from the electron emission window 2022. After passing through the patient, they are received by the CT detector to form an image. The process of electrons bombarding the anode target disk will generate a large amount of heat. If the bombardment position remains unchanged, the bombarded area of ​​the anode target disk will generate a large amount of heat, and the heat generation rate is much greater than its heat dissipation rate. When the heat accumulates to a critical value, the bombarded area of ​​the target surface melts, causing the anode to fail. Therefore, in the prior art, the X-ray tube 200 generally adopts a rotating anode, that is, the anode target disk is in a rotating state during operation, so that the position of the electron bombardment on the anode target disk continuously changes, avoiding the phenomenon of local temperature increase and damage to the anode target disk.

[0045] Next, we will combine Figures 2 to 7 The structure and working principle of the cathode assembly 100 used in the X-ray tube 200 are exemplarily described.

[0046] Figure 2 yes Figure 1 Section view along AA perspective, Figure 3 yes Figure 2 A partial enlarged view of area B.

[0047] refer to Figure 2 and Figure 3The cathode assembly 100 comprises: a cable fixing portion 1 for fixing a cable 2, the cable fixing portion 1 having a first end 11 and a second end 12 opposite to each other, the first end 11 facing the vacuum region, the second end 12 facing the non-vacuum region, the cable 2 at least comprising a high-voltage cable core 21; an electron emitting portion 3, the electron emitting portion 3 comprising a head 31 and a connecting tube 32, the connecting tube 32 being sleeved on the first end 11 and being suitable for enclosing an accommodating space 33, the head 31 and the first end 11 respectively sealing both ends of the connecting tube 32; at least one filament 4 , arranged on the side of the head 31 away from the connecting tube 32, the filament 4 is used to emit electrons; the high-voltage pin 5 is arranged in the accommodating space 33 and has a third end 51 and a fourth end 52 opposite to each other, the third end 51 is coupled to the at least one filament 4, and the fourth end 52 passes through the first end 11 and is coupled to the high-voltage cable core 21; the connecting portion 6 is used to electrically connect the connecting tube 32 and the high-voltage pin 5; wherein the portion of the connecting tube 32 sleeved on the first end 11 at least extends toward the second end 12 to exceed the fourth end 52.

[0048] Therefore, by electrically connecting the high-voltage pin 5 with the connecting tube 32, the electric field distribution can be made more uniform, effectively avoiding the electric field gathering at the connection between the high-voltage pin 5 and the high-voltage cable core 21 to cause discharge or flashover, thereby improving the safety, stability and reliability of the use of the X-ray tube 200.

[0049] Specifically, combined Figure 2 and Figure 3 The cable fixing part 1 fixes the cable 2 on the housing 202 so that at least a portion of the cable 2 penetrates into the vacuum cavity 2021 defined by the housing 202. In other words, at least a portion of the cable 2 is located in the vacuum area. The vacuum area refers to the area within the vacuum cavity 2021.

[0050] In some embodiments, in combination Figure 3 and Figure 4 The cable fixing part 1 may be funnel-shaped. The housing 202 includes a mounting tube 2023 protruding in the opposite direction of the first direction D1, and the mounting tube 2023 has an opening opened in the opposite direction of the first direction D1, and the first end 11 of the cable fixing part 1 can extend into the vacuum chamber 2021 from the opening.

[0051] Furthermore, the outer circumferential surface of the cable fixing portion 1 extending into the installation tube 2023 is tightly fitted with the inner wall of the installation tube 2023 to ensure the airtightness of the vacuum chamber 2021 .

[0052] In some embodiments, the cable fixing portion 1 has a circle of bosses 16 extending outward, and the lower surface of the bosses 16 facing the first direction D1 can be tightly fitted with the end of the mounting tube 2023 facing the opposite direction of the first direction D1. Thus, the connection area between the cable fixing portion 1 and the housing 202 can be further increased, making the connection between the cable fixing portion 1 and the housing 202 more stable, increasing the reliability and stability of the X-ray tube 200, and ensuring the airtightness of the vacuum chamber 2021.

[0053] In some embodiments, the connection between the cable fixing portion 1 and the housing 202 may be fixedly connected by brazing or the like, thereby further enhancing the airtightness of the vacuum chamber 2021 .

[0054] In some embodiments, in combination Figure 4 and Figure 7 The cable fixing portion 1 may further include: a cover portion 13, suitable for forming the first end 11; a sleeve portion 14, connected to the cover portion 13, the sleeve portion 14 is provided with an assembly hole 15 extending in the direction from the second end 12 to the first end 11, at least a portion of the cable 2 is accommodated in the assembly hole 15, the outer peripheral surface of the cable 2 is in contact with the inner wall of the assembly hole 15, and the end surface of the cable 2 facing the first end 11 is in contact with the cover portion 13.

[0055] In some embodiments, the cover portion 13 and the sleeve portion 14 are integrally formed (eg Figure 4 and Figure 5 As shown). As a result, the cable fixing part 1 has better integrity and better sealing, which is beneficial to ensure the vacuum environment inside the housing 202.

[0056] In some embodiments, the cover portion 13 and the sleeve portion 14 may also be two independent components (eg Figure 7 As shown). Thus, the cover 13 and the sleeve 14 can be processed separately, which reduces the processing difficulty. Further, when the cable fixing part 1 is assembled, the cover 13 and the sleeve 14 can be tightly connected together by brazing or the like to enhance the structural stability of the cable fixing part 1.

[0057] In some embodiments, the cover portion 13 and the sleeve portion 14 are both made of insulating material, which may be selected from, for example, ceramics, hard glass, and the like.

[0058] In some embodiments, the sleeve portion 14 and the cover portion 13 are made of the same material. Thus, the same materials are more compatible when connected, which can further ensure the tightness of the connection and avoid air leakage that affects the airtightness of the vacuum chamber 2021.

[0059] Continue to refer Figure 2and Figure 3 The electron emitting part 3 includes a head 31 and a connecting tube 32. The connecting tube 32 is sleeved on the first end 11 and is suitable for enclosing an accommodating space 33. The head 31 and the first end 11 respectively seal the two ends of the connecting tube 32. The electron emitting part 3 is used to emit electrons toward the anode assembly 201 to generate X-rays.

[0060] In some embodiments, in combination Figures 2 to 4 , the cable fixing part 1 includes a first section 101 and a second section 102. The first end 11 is located in the first section 101, and the second end is located in the second section. Further, along a plane perpendicular to the first direction D1, the cross-sectional area of ​​the first section 101 is smaller than the cross-sectional area of ​​the second section 102, and a step structure is formed between the first section 101 and the second section 102. Further, at least a portion of the connecting tube 32 is sleeved on the first section 101, and the end surface of the connecting tube 32 facing the opposite direction of the first direction D1 abuts against the step structure between the first section 101 and the second section 102. As a result, the connection between the connecting tube 32 and the cable fixing part 1 is more stable and reliable, avoiding relative displacement between the connecting tube 32 and the cable fixing part 1 in the high vibration environment of the rotating anode.

[0061] Furthermore, the inner wall of the connecting tube 32 and the outer circumference of the first section 101 are closely fitted, or the inner wall of the connecting tube 32 and the outer circumference of the first section 101 can be fixedly connected by brazing or the like. Thus, the connection between the cable fixing part 1 and the electron emitting part 3 is more firmly connected, thereby increasing the reliability of the operation of the X-ray tube 200.

[0062] In some embodiments, the head 31 is connected to a side of the connecting tube 32 facing away from the cable fixing portion 1 , and the electron beam is emitted from the head 31 .

[0063] In some embodiments, the head 31 may be made of insulating material, the connecting tube 32 may be made of conductive material, and the head 31 and the connecting tube 32 may be fixedly connected by brazing, etc. Thus, the structural stability of the electron emission portion 3 can be further enhanced.

[0064] Furthermore, the head 31 , the connecting tube 32 and the first end 11 together enclose the accommodating space 33 .

[0065] Further, refer to Figure 2 , Figure 3 , Figure 5 and Figure 6 The cathode assembly 100 further includes at least one filament 4 disposed on a side of the head 31 away from the connecting tube 32 , and the filament 4 is used to emit electrons.

[0066] Specifically, refer to Figure 5 and Figure 6 In some embodiments, a groove structure 35 may be provided on one side of the head 31 facing the first direction D1 for accommodating the filament 4. Thus, the groove structure 35 can be used to protect the filament 4 and guide the emission direction of the electron beam.

[0067] In some embodiments, the number of the filament 4 may be one, thereby saving production costs.

[0068] In some embodiments, the number of the filaments 4 may also be two or more. For example, in a dual-focus or multi-focus X-ray tube, two or more filaments 4 may be provided.

[0069] In the embodiment of the present invention, Figure 5 and Figure 6 As shown, an exemplary description is given by taking the number of filaments 4 as two.

[0070] In a typical application scenario, the positions of the two filaments 4 and the magnitude of the current flowing therethrough can be adjusted so that the two filaments 4 act on a focus at the same time and the focus can be adjusted.

[0071] Further reference Figure 3 and Figure 5 The third end 51 of the high voltage pin 5 is coupled to the filament 4, and the fourth end 52 passes through the first end 11 and is coupled to the high voltage cable core 21. Thus, the high voltage electricity transmitted by the high voltage cable core 21 passes through the high voltage pin 5 to the filament 4, so as to form a strong electric field between the filament 4 and the anode assembly 201, thereby accelerating the generation of the electron beam.

[0072] It is worth noting that the specific value of the voltage of the high voltage depends on the design of the X-ray tube, the application field, and the required X-ray energy and quality. Taking a medical X-ray tube as an example, the voltage of the high voltage input in a diagnostic X-ray machine (such as a CT machine) generally ranges from tens of kilovolts to hundreds of kilovolts.

[0073] Furthermore, the cathode assembly 100 further includes a connection portion 6 disposed in the accommodation space 33. The connection portion 6 is used to electrically connect the connection tube 32 and the high voltage pin 5. In other words, through the connection portion 6, the high voltage electricity from the high voltage cable core 21 is also passed through the connection tube 32.

[0074] Furthermore, the portion of the connecting tube 32 sleeved on the first end 11 extends in the opposite direction of the first direction D1 to exceed the fourth end 52. In other words, along the direction perpendicular to the first direction D1, the projection of the connecting tube 32 at least covers the projection of the fourth end 52. Thus, electrically connecting the high-voltage pin 5 and the connecting tube 32 through the connecting portion 6 can guide the electric field 300 away from the accommodating space 33, especially away from the connection between the high-voltage cable core 21 and the high-voltage pin 5, so as to avoid sparking, discharge and other phenomena at the connection between the high-voltage cable core 21 and the fourth end 52 of the high-voltage pin 5, causing serious failure or even damage to the X-ray tube 200, thereby improving the safety of the use of the X-ray tube 200 and further extending the service life of the X-ray tube.

[0075] Further, combined with Figure 2 , Figure 3 and Figure 5 , since the connecting tube 32 is made of conductive material, there are a large number of free electrons inside the conductive material, and these free electrons can move freely under the action of the electric field, thereby balancing the charge distribution inside the material until a stable state is reached, that is, the charge density is equal everywhere inside the material, thereby maintaining the uniformity of the electric potential. When the connecting tube 32 is in the electric field, due to its conductivity, the connecting tube 32 will quickly become an equipotential body. That is, the electric potential is the same everywhere in the connecting tube 32. Further, during the operation of the X-ray tube, the electric field 300 between the cable fixing part 1 and the electron emitting part 3 is formed on the periphery of the connecting tube 32. As a result, the connecting tube 32 can avoid the electric field from being concentrated inside the connecting tube 32, especially avoiding the electric field from being concentrated at the connection between the high-voltage cable core 21 and the high-voltage pin 5, making the distribution of the electric field 300 more uniform, and enhancing the reliability, stability and safety of the use of the X-ray tube 200.

[0076] In some embodiments, in combination Figure 5 and Figure 6 The cathode assembly 100 further includes: a plurality of filament pins 7, corresponding to the at least one filament 4, wherein every two of the filament pins 7 are respectively connected to the two ends of the corresponding filament 4 to supply power to the filament 4, at least a portion of the filament pins 7 is accommodated in the accommodation space 33, and the high-voltage pin 5 reuses at least one of the plurality of filament pins 7. Thus, there is no need to additionally set an electrical connection structure for supplying high voltage power to the filament 4, which can simplify the structure of the cathode assembly 100 and reduce production costs.

[0077] Specifically, for each filament 4, two ends of the filament 4 are respectively connected to two filament pins 7. Through the two filament pins 7, low voltage electricity can be input to the filament 4 to make the filament 4 emit electrons. The low voltage electricity to the filament 4 is generally less than 10 volts. Therefore, the low voltage electricity can be used to heat the filament 4 so that the filament 4 generates enough electrons, and can also prevent the voltage on the filament 4 from being too high and damaging the filament.

[0078] In some embodiments, a low voltage current flows in through one of the two filament pins 7 connected to both ends of the filament 4 and flows out through the other one.

[0079] In some embodiments, the high voltage pin 5 reuses at least one of the multiple filament pins 7. It should be understood that the high voltage pin 5 is used to input high voltage electricity to the filament 4, but a complete high voltage circuit is not formed in the entire cathode assembly 100. That is, the filament 4 is not actually in the high voltage circuit. The function of the high voltage cable core 21 inputting high voltage electricity to the filament 4 through the high voltage pin 5 is to form a strong electric field between the cathode assembly 100 and the anode assembly 201 to accelerate the filament 4 to emit an electron beam.

[0080] Furthermore, a window portion 34 is provided on the wall of the connecting tube 32, and the window portion 34 at least partially exposes the high-voltage pin 5 and the connecting portion 6 accommodated in the accommodating space 33. Thus, through the window portion 34, the operation of connecting the two ends of the connecting portion 6 to the high-voltage pin 5 and the connecting tube 32 respectively can be made more convenient.

[0081] In some embodiments, reference Figure 2 , Figure 3 and Figure 5 The cable 2 also includes: a low-voltage cable core 22, both ends of each of the at least one filament 4 are electrically connected to the low-voltage cable core 22, and the low-voltage cable core 22 is used to input low-voltage electricity to the filament 4 to heat the filament 4 to generate electrons.

[0082] Further, the high-voltage cable core 21 and the low-voltage cable core 22 are insulated from each other and arranged in the cable 2, and the outer peripheral surface of the high-voltage cable core 21 and the outer peripheral surface of the low-voltage cable core 22 are respectively covered with an insulating layer 23, and the cable fixing part 1 fixes the cable 2 by fixing the insulating layer 23. Thus, the insulating layer 23 can ensure that the high-voltage cable core 21 and the low-voltage cable core 22 do not interfere with each other.

[0083] Further, after the cable 2 is inserted into the assembly hole 15, the high-voltage cable core 21, the low-voltage cable core 22 and the insulating layer 23 are substantially flush on the end face of the cable 2 facing the first direction D1. In addition, the end face of the cable 2 is closely fitted with the surface of the cover 13 exposed to the assembly hole 15. Thus, the connection between the cable 2 and the cable fixing part 1 is closely fitted, which can avoid the generation of an assembly gap and affect the airtightness of the vacuum chamber 2021.

[0084] In some embodiments, the high-voltage cable core 21 and the low-voltage cable core 22 can be connected to the same external power supply to simplify the structure of the entire X-ray machine (eg, a CT machine) and reduce production costs.

[0085] In some embodiments, reference Figure 5 The high voltage pin 5 may include a first needle portion 53 and a second needle portion 54 that are directly or indirectly electrically connected, wherein the third end 51 is formed at the first needle portion 53, the fourth end 52 is formed at the second needle portion 54, and the second needle portion 54 penetrates the first end 11 and is connected to the cable 2. Thus, the high voltage pin 5 is divided into the first needle portion 53 and the second needle portion 54, which can make the assembly of the cathode assembly 100 more convenient.

[0086] Specifically, the first needle portion 53 may be fixedly connected to the head portion 31 of the electron emitting portion 3 in advance, and electrically connected to the filament 4. The second needle portion 54 may be fixedly connected to the first end 11 of the cable fixing portion 1 in advance, and electrically connected to the high-voltage cable core 21. Thus, when the connecting tube 32 of the electron emitting portion 3 is connected to the cable fixing portion 1, the first needle portion 53 and the second needle portion 54 may be close to each other for coupling.

[0087] In some embodiments, the first needle portion 53 and the second needle portion 54 may be electrically connected via a conductive sheet or other structure.

[0088] In some embodiments, the first needle portion 53 and the second needle portion 54 may be fixedly connected by welding or the like after being aligned and brought close to each other.

[0089] In some embodiments, the connecting portion 6 can electrically connect the first needle portion 53 and the connecting cylinder 32 .

[0090] In a preferred embodiment, the connecting portion 6 can also electrically connect the second needle portion 54 and the connecting tube 32. Therefore, even if the electrical connection between the first needle portion 53 and the second needle portion 54 fails, the connecting tube 32 can still be used to prevent the electric field from being concentrated at the connection between the high-voltage pin 5 and the high-voltage cable core 21, so as to avoid arcing, sparking, etc., which is beneficial to protecting the internal structure of the cathode assembly 100.

[0091] Further, combined with Figure 4 , Figure 5 and Figure 7, the first end 11 is provided with a plurality of mounting through holes 111, and the number of the second needle parts 54 is a plurality, and the plurality of mounting through holes 111 correspond to the plurality of second needle parts 54 one by one, wherein each second needle part 54 passes through the first end 11 from the corresponding mounting through hole 111, and the inner wall of the mounting through hole 111 fits with the outer peripheral surface of the corresponding second needle part 54. Thus, through the mounting through hole 111, the second needle part 54 can pass through the first end 11, and the two ends of the second needle part 54 can be electrically connected to the high-voltage cable core 21 and the first needle part 53, respectively. Moreover, the inner wall of the mounting through hole 111 fits closely with the outer peripheral surface of the corresponding second needle part 54, and can also prevent the air outside the vacuum chamber 2021 from entering the vacuum chamber 2021 from the assembly gap, affecting the normal use of the X-ray tube 200.

[0092] In some embodiments, in combination Figure 5 , Figure 7 and Figure 8 The second needle portion 54 includes a first section 541 and a second section 542, wherein at least a portion of the first section 541 extends out of the mounting through hole 111 and is inserted into the accommodating space 33, and the second section 542 is located in the mounting through hole 111. On a plane perpendicular to the extension direction of the second needle portion 54, the cross-sectional area of ​​the second section 542 is greater than the cross-sectional area of ​​the first section 541.

[0093] Specifically, along the extension direction of the second needle portion 54, at least a portion of the first section 541 extends out of the mounting through hole 111 so as to be electrically connected to the first needle portion 53. The second section 542 is accommodated in the mounting through hole 111 so as to be electrically connected to the high-voltage cable core 21. Further, along the plane perpendicular to the first direction D1, the cross-sectional area of ​​the second section 542 is greater than the cross-sectional area of ​​the first section 541. Accordingly, the shape of the mounting through hole 111 is adapted to the shape of the second needle portion 54, that is, the wall used to form the mounting through hole 111 protrudes toward the inside of the mounting through hole 111 to form a step structure. Thus, when the second needle portion 54 is inserted into the mounting through hole 111 and installed in place, the second section 542 abuts against the step structure. Thus, the contact area between the second needle portion 54 and the mounting through hole 111 is further increased to make the connection between the two more secure. At the same time, the displacement of the second needle portion 54 relative to the mounting through hole 111 along the first direction D1 is avoided.

[0094] In some embodiments, the cathode assembly 100 further includes: a sealing gasket 8, which is located on the surface of the cable fixing portion 1 facing the filament 4, and the sealing gasket 8 is sleeved on the second needle portion 54 to seal the gap between the second needle portion 54 and the mounting through hole 111. In this way, the sealing performance of the vacuum chamber 2021 can be further ensured.

[0095] Further, combined with Figure 2 , Figure 3 , Figure 5 and Figure 8 , at the connection between the fourth end 52 and the high-voltage cable core 21, on a plane perpendicular to the first direction, the cross-sectional area of ​​the high-voltage cable core 21 is equal to the cross-sectional area of ​​the high-voltage pin 5, wherein the first direction is parallel to the direction of the second end 12 pointing to the first end 11. Thus, pure contact power conduction can be used to avoid the presence of air at the connection, causing the electric field to gather at the contact position of the metal, the insulating material and the air, thereby generating electric field distortion, causing intrinsic breakdown or surface flashover of the insulating material, and these insulation damage phenomena will damage the X-ray tube 200 and affect the service life of the X-ray tube 200.

[0096] In some embodiments, when the fourth end 52 and the high-voltage cable core 21 are electrically connected, along a plane perpendicular to the first direction D1, the cross-sectional area of ​​the high-voltage cable core 21 is the same as the cross-sectional area of ​​the second section 542. In other words, the outer circumference of the high-voltage cable core 21 and the outer circumference of the second section 542 are smoothly butted.

[0097] Furthermore, the cathode assembly 100 also includes: a protrusion 91, which is arranged on one of the high-voltage cable core 21 and the high-voltage pin 5 and protrudes toward the other one; and a recessed portion 92, which is arranged on the other one of the high-voltage cable core 21 and the high-voltage pin 5 to receive the protrusion 91.

[0098] In some embodiments, reference Figure 8 , the protrusion 91 is provided on the high-voltage cable core 21, and the recessed portion 92 is provided on the high-voltage pin 5. Further, when the high-voltage cable core 21 and the high-voltage pin 5 are electrically connected, the protrusion 91 is inserted into the recessed portion 92. Thus, by increasing the contact area, the contact resistance can be effectively reduced, and the risk of power failure is reduced.

[0099] In some embodiments, the high-voltage cable core 21 includes: a needle 211, which is used to be electrically connected to the fourth end 52; a needle tube 212, which has a housing cavity 2121 extending along a first direction, at least a portion of the needle 211 is accommodated in the housing cavity 2121 and can reciprocate along the first direction; an elastic mechanism 213, which is arranged in the housing cavity 2121, and the elastic mechanism 213 is used to hold the needle 211 against the fourth end 52. Thus, through the elastic mechanism 213, the needle 211 can be firmly held against the fourth end 52, so that the electrical connection between the high-voltage cable core 21 and the high-voltage pin 5 is more reliable and stable.

[0100] It should be understood that the above mainly exemplifies the specific structure and matching mode of the high-voltage cable core 21 and the high-voltage pin 5. In the embodiment of the present application, the structure and function of the low-voltage cable core 22 can refer to the description of the high-voltage cable core 21, and except for the filament pin 7 that is multiplexed as the high-voltage pin 5, the structure and function of other filament pins 7 can also refer to the specific description of the high-voltage pin 5.

[0101] From the above, by adopting the technical solution of the embodiment of the present application, by electrically connecting the high-voltage pin 5 with the connecting tube 32, the electric field distribution can be made more uniform, and the electric field can be effectively prevented from gathering at the connection between the high-voltage pin 5 and the high-voltage cable core 21 to cause discharge or flashover, thereby improving the safety, stability and reliability of the use of the X-ray tube 200.

[0102] Furthermore, the cross-sectional area of ​​the high-voltage cable core 21 is equal to the cross-sectional area of ​​the high-voltage pin 5. Pure contact power conduction can be used to avoid the presence of air at the connection, which causes the electric field to gather at the contact position of the metal, the insulating material and the air, thereby generating electric field distortion, causing intrinsic breakdown or surface flashover of the insulating material. These insulation damage phenomena will damage the X-ray tube 200 and affect the service life of the X-ray tube 200. At the same time, the electric field 300 at the electrical connection can be made more uniform.

[0103] Furthermore, the electrical connection between the high-voltage cable core 21 and the high-voltage pin 5 is achieved through the cooperation of the protrusion 91 and the recessed portion 92 . By increasing the contact area, the contact resistance can be effectively reduced, thereby reducing the risk of power failure.

[0104] It should be understood that the term "and / or" herein is merely an association relationship describing associated objects, indicating that three relationships may exist, for example, A and / or B, which may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " herein indicates that the associated objects before and after are in an "or" relationship. As used herein, unless otherwise expressly stated, the term "or" covers all possible combinations unless it is not feasible. For example, if a component is stated to include A or B, then unless otherwise expressly stated or not feasible, the component may include A, or B, or A and B. As a second example, if a component is stated to include A, B, or C, then unless otherwise expressly stated or not feasible, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C. The "multiple" appearing in the embodiments of the present application refers to two or more.

[0105] The relational terms appearing in the embodiments of the present application, such as first, second, etc., are only used to distinguish an entity or operation from another entity or operation, and do not require or imply any actual relationship or order between these entities or operations. In addition, the words "include", "have" and "comprise" and other similar forms are intended to be equivalent in meaning, and are open-ended, and one or more items behind any of these words are not meant to be an exhaustive list of such one or more items, or mean to be limited to one or more items listed. In the accompanying drawings and the specification, exemplary embodiments have been disclosed. However, many changes and modifications can be made to these embodiments. Therefore, although specific terms have been adopted, they are only used in a general and descriptive sense, not for the purpose of limitation.

[0106] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

[0107] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A cathode assembly for an X-ray tube, characterized in that: include: A cable fixing portion, used for fixing a cable, the cable fixing portion having a first end and a second end opposite to each other, the first end facing the vacuum area, the second end facing the non-vacuum area, the cable comprising at least a high-voltage cable core; An electron emitting part, the electron emitting part comprising a head and a connecting tube, the connecting tube is sleeved on the first end and is suitable for enclosing an accommodating space, the head and the first end respectively seal two ends of the connecting tube; at least one filament, arranged on a side of the head away from the connecting tube, the filament being used to emit electrons; A high-voltage pin, at least partially disposed in the accommodating space and having a third end and a fourth end opposite to each other, the third end being coupled to the at least one filament, and the fourth end penetrating the first end and being coupled to the high-voltage cable core; A connecting portion, used for electrically connecting the connecting tube and the high voltage pin; Wherein, the portion of the connecting tube sleeved on the first end at least extends toward the second end and beyond the fourth end.

2. The cathode assembly according to claim 1, characterized in that The connecting tube is made of conductive material, and the electric potential at each location of the connecting tube is the same. During the operation of the X-ray tube, an electric field between the cable fixing portion and the electron emitting portion is formed at the periphery of the connecting tube.

3. The cathode assembly according to claim 1, characterized in that Also includes: A plurality of filament pins correspond to the at least one filament, wherein every two of the filament pins are respectively connected to the two ends of the corresponding filament to supply power to the filament, at least a portion of the filament pins is accommodated in the accommodation space, and the high-voltage pin reuses at least one of the plurality of filament pins.

4. The cathode assembly according to claim 1, characterized in that A window portion is formed on the wall of the connecting tube, and the window portion at least partially exposes the high-voltage pin and the connecting portion accommodated in the accommodating space.

5. The cathode assembly according to claim 1, characterized in that The cable also includes: A low-voltage cable core, both ends of each filament of the at least one filament are electrically connected to the low-voltage cable core respectively, and the low-voltage cable core is used to input low-voltage electricity to the filament to heat the filament to generate electrons.

6. The cathode assembly according to claim 5, characterized in that The high-voltage cable core and the low-voltage cable core are insulated from each other and arranged in the cable, and the outer circumference of the high-voltage cable core and the outer circumference of the low-voltage cable core are respectively covered with insulation layers, and the cable fixing part fixes the cable by fixing the insulation layers.

7. The cathode assembly according to claim 1, characterized in that The high voltage pin includes a first needle portion and a second needle portion which are directly or indirectly electrically connected, wherein the third end is formed at the first needle portion, the fourth end is formed at the second needle portion, and the second needle portion penetrates the first end and is connected to the cable.

8. The cathode assembly according to claim 7, characterized in that The connecting portion electrically connects the second needle portion and the connecting cylinder.

9. The cathode assembly according to claim 7, characterized in that: The first end is provided with a plurality of mounting through holes, and the number of the second needle parts is multiple, and the plurality of mounting through holes corresponds one-to-one to the plurality of second needle parts, wherein each second needle part passes through the first end from the corresponding mounting through hole, and the inner wall of the mounting through hole is in contact with the outer peripheral surface of the corresponding second needle part.

10. The cathode assembly according to claim 9, characterized in that The second needle portion includes a first section and a second section, wherein at least a portion of the first section extends out of the mounting through hole and is inserted into the accommodating space, and the second section is located in the mounting through hole. On a plane perpendicular to the extension direction of the second needle portion, a cross-sectional area of ​​the second section is greater than a cross-sectional area of ​​the first section.

11. The cathode assembly according to claim 9, characterized in that Also includes: A sealing gasket is located on a surface of the cable fixing portion facing the filament, and the sealing gasket is sleeved on the second needle portion to seal a gap between the second needle portion and the mounting through hole.

12. The cathode assembly according to claim 1, characterized in that At the connection between the fourth end and the high-voltage cable core, on a plane perpendicular to a first direction, a cross-sectional area of ​​the high-voltage cable core is equal to a cross-sectional area of ​​the high-voltage pin, wherein the first direction is parallel to a direction from the second end to the first end.

13. The cathode assembly according to claim 12, characterized in that Also includes: A protrusion, disposed on one of the high-voltage cable core and the high-voltage pin and protruding toward the other one; A recessed portion is disposed on the other of the high-voltage cable core and the high-voltage pin to receive the protruding portion.

14. The cathode assembly according to claim 12, characterized in that The high voltage cable core comprises: a needle, used for being electrically connected to the fourth end; A needle tube having a receiving cavity extending along a first direction, wherein at least a portion of the needle is received in the receiving cavity and can reciprocate along the first direction; An elastic mechanism is disposed in the accommodating cavity, and the elastic mechanism is used to hold the needle against the fourth end.

15. The cathode assembly according to claim 1, characterized in that The cable fixing member comprises: a cover portion, adapted to form the first end; A sleeve portion is connected to the cover portion, and the sleeve portion is provided with an assembly hole extending in a direction from the second end to the first end, at least a portion of the cable is accommodated in the assembly hole, the outer peripheral surface of the cable is in contact with the inner wall of the assembly hole, and the end surface of the cable facing the first end is in contact with the cover portion.

16. The cathode assembly according to claim 15, characterized in that The cover portion and the sleeve portion are integrally formed; and / or The cover portion and the sleeve portion are both made of insulating material; and / or The sleeve portion and the cover portion are made of the same material.

17. An X-ray tube, characterized in that: include: The cathode assembly according to any one of claims 1 to 16; an anode assembly, for receiving electrons emitted by the cathode assembly to generate X-rays; The housing has a vacuum chamber, and at least a portion of the anode assembly and the cathode assembly are located in the vacuum chamber.

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