X-ray tube cathode insulation assembly

Abstract

The invention relates to the technical field of X-ray tube manufacturing, in particular to an X-ray tube cathode insulation assembly. Comprising a cathode insulator and a cathode plate, the cathode insulator comprises a ceramic body and a metal connecting piece fixed at the end part of the ceramic body, a connecting ring is arranged on the cathode plate, the connecting ring is connected with the metal connecting piece, and an annular protective cover is fixed on the connecting ring. And the annular protective cover covers the radial outer side of the axial connecting position of the ceramic body and the metal connecting piece. And the influence of surface flashover can be effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of X-ray tube manufacturing, and in particular to a cathode insulation component of an X-ray tube. Background Art

[0002] The medical X-ray diagnostic equipment, computer tomography (CT), uses an X-ray tube assembly for X-ray photography. The X-ray tube assembly includes a tube housing and an X-ray tube. The X-ray tube is housed in the tube housing and radiates X-rays. The tube housing is provided with an X-ray radiation window for X-rays to pass through, and lead plates for shielding X-rays are adhered to other parts of the inner wall of the tube housing.

[0003] The X-ray tube includes a cathode, an anode target and a vacuum shell. The cathode is opposite to the anode target and is offset relative to the rotation axis of the anode. In the vacuum environment formed by the vacuum shell, when a high voltage is applied between the cathode and the anode target, the cathode emits electrons, which are accelerated to the anode and collide with the target surface. The anode target radiates X-rays and is emitted through the window on the shell.

[0004] In a high-performance X-ray tube, when a certain voltage is applied to the cathode and anode, the local field strength at the junction of the metal near the cathode electrode end, the insulating ceramic material and the vacuum is very high, causing field-induced electron emission, which is easy to form surface flashover and induce the X-ray tube to spark and fail. Summary of the invention

[0005] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides an X-ray tube cathode insulation assembly, which can effectively avoid the influence of surface flashover.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions: An X-ray tube cathode insulation assembly comprises a cathode insulator and a cathode plate, wherein the cathode insulator comprises a ceramic body and a metal connector fixed to the end of the ceramic body, a connecting ring is provided on the cathode plate, the connecting ring is connected to the metal connector, an annular protective cover is fixed on the connecting ring, and the annular protective cover is arranged radially outside the axial connection position of the ceramic body and the metal connector.

[0007] Furthermore, in an X-ray tube cathode insulation assembly in the present application, a spacing chamber is provided between the annular protective cover, the metal connector and the ceramic body in radial direction, the spacing chamber includes a protection chamber and an extension chamber in the axial direction in sequence, the axial position of the protection chamber corresponds to the connection position of the ceramic body and the metal connector, the extension chamber is arranged on the outside of the metal connector, and the width of the protection chamber is greater than the extension chamber. As a preferred embodiment of the present application, it should be noted that the width of the spacing chamber is not its radial dimension, but the radial spacing between the annular protective cover and the ceramic body or the metal connector, the extension chamber extends with the metal connector, and the width of the protection chamber is greater than the extension chamber, that is, the gap is increased at the position where surface flashover is prone to occur.

[0008] Furthermore, in the present application, an X-ray tube cathode insulation assembly, the annular protective cover has an annular inner edge extending radially inwardly from one end of the protective cavity away from the extension cavity. As a preferred solution of the present application, the annular inner edge is provided at the upper end of the protective cavity to form a closing close to the ceramic body.

[0009] Furthermore, in the present application, a cathode insulating assembly of an X-ray tube is provided, wherein a cathode cover is welded to the bottom of the connecting ring. As a preferred embodiment of the present application, when the electrons emitted by the cathode filament bombard the anode target plate, a large amount of metal vapor is released while the anode generates X-rays. In addition, local heating of the cathode itself will also release metal vapor. Metal vapor contacting the cathode ceramic part will damage the ceramic. In order to reduce the impact, a cathode cover is provided to block the metal vapor.

[0010] It can be seen from the above technical solution that the present invention has the following beneficial effects: The connection position between the ceramic body and the metal connector is placed in the vacuum environment of the cathode tube shell. The interface between the solid medium formed by the ceramic body and the metal connector and the vacuum is the weakest link in surface flashover. An X-ray tube cathode insulation assembly in the present application can effectively avoid the influence of surface flashover by adding an annular protective cover at this position. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic structural diagram of a cathode insulator assembly in one embodiment of the present application; Figure 2 This is a schematic diagram of the structure of an annular protective cover in an embodiment of the present application; Figure 3 is a cross-sectional view of an annular protective cover in one embodiment of the present application; Figure 4 is a schematic diagram of a cathode tube shell in an embodiment of the present application; Figure 5 An exploded view of the cathode tube shell in one embodiment of the present application; Figure 6It is a plan view of the metal tube shell body in one embodiment of the present application.

[0012] In the figure: 1-metal tube shell body; 11-cathode shielding plate; 111-connecting groove; 112-convex rib; 12-cover body; 120-throw hole; 121-insulator storage sleeve; 122-cathode plate storage ring; 123-connecting end surface; 2- cathode insulator; 21- metal connecting ring; 22- ceramic body; 23- metal connecting piece; 3- anode housing; 4- cathode plate; 41- connecting ring; 42- cathode cover plate; 5- annular protective cover; 50- compartment chamber; 501- protective chamber; 502- extension chamber; 51- annular inner edge; 6-Nickel needle; 7-Filament. DETAILED DESCRIPTION

[0013] Example 1 Combination Figure 1 As shown, this embodiment provides an X-ray tube cathode insulation assembly, including a cathode insulator 2 and a cathode plate 4, the cathode insulator 2 includes a ceramic body 22 and a metal connector 23 fixed to the end of the ceramic body 22, the cathode plate 4 is provided with a connecting ring 41, the connecting ring 41 is connected to the metal connector 23, an annular protective cover 5 is fixed to the connecting ring 41, and the annular protective cover 5 is provided on the radial outside of the axial connection position of the ceramic body 22 and the metal connector 23.

[0014] Based on the above structure, an X-ray tube cathode insulation component is provided, the principle of which is: wherein the metal connector 23 is connected to the cathode plate 4 as a whole through the connecting ring 41, and the filament 7 on the cathode plate 4 is biased. The nickel needle 6 is provided on the ceramic body 22, and the nickel needle 6 supplies the filament voltage to the filament 7 through the nickel wire and applies high voltage to the cathode end. The metal connector 23, the connecting ring 41 and the cathode plate 4 are all conductive metals, forming a cathode high-voltage electrode as a whole. The connection position of the ceramic body 22 and the metal connector 23 is placed in the vacuum environment in the cathode tube shell. The interface between the solid medium formed by the ceramic body 22 and the metal connector 23 and the vacuum is the weakest link of the surface flashover. In this embodiment, an X-ray tube cathode insulation component can effectively avoid the influence of the surface flashover by adding an annular protective cover 5 at this position.

[0015] In this embodiment, a spacing chamber 50 is provided between the annular protective cover 5 and the metal connector 23 and the ceramic body 22 in the radial direction. The spacing chamber 50 includes a protection chamber 501 and an extension chamber 502 in the axial direction in sequence. The axial position of the protection chamber 501 corresponds to the connection position of the ceramic body 22 and the metal connector 23. The extension chamber 502 is arranged on the outside of the metal connector 23, and the width of the protection chamber 501 is greater than the extension chamber 502. It should be noted that the width of the spacing chamber 50 is not its radial dimension, but the radial spacing between the annular protective cover 5 and the ceramic body 22 or the metal connector 23. The extension chamber 502 extends with the metal connector 23, and the width of the protection chamber 501 is greater than the extension chamber 502, that is, the gap is increased at the position where surface flashover is prone to occur.

[0016] Combination Figure 2 and Figure 3 As shown, in this embodiment, the annular protective cover 5 is provided with an annular inner edge 51 extending radially inwardly from one end of the protective cavity 501 away from the extension cavity 502. The annular inner edge 51 is provided at the upper end of the protective cavity 501 to form a closing end close to the ceramic body 22.

[0017] In this embodiment, a cathode cover plate 42 is welded to the bottom of the connecting ring 41. When the electrons emitted by the cathode filament bombard the anode target plate, a large amount of metal vapor will be released while the anode generates X-rays. In addition, the local heating of the cathode itself will also release metal vapor. Metal vapor will damage the cathode ceramic part when it contacts the ceramic. In order to reduce the impact, the cathode cover plate 42 is provided to block the metal vapor.

[0018] Example 2 Based on Example 1, Figures 4 to 5 As shown, this embodiment provides a cathode tube shell, including a metal tube shell main body 1, the metal tube shell main body 1 is connected to the end of the anode shell 3, the metal tube shell main body 1 includes a cover body 12 with openings at both axial ends and a cathode shielding plate 11 welded to the cover body 12 at one end near the anode shell 3, the cathode shielding plate 11 is arranged between the anode shell 3 and the cover body 12, and a cathode insulator 2 is fixedly provided in the metal tube shell main body 1, and the cathode insulator 2 is sealed at the open end of the cover body 12 away from the cathode shielding plate 11.

[0019] Based on the above structure, the cathode shell has the following principle: by using the metal shell body 1, it is possible to effectively avoid the inner wall from being easily attached with metal vapor and causing ignition cracking, and the cathode shielding plate 11 effectively isolates the metal shell body 1 and the anode shell 3, preventing the heat of the anode target disk in the anode shell 3 from radiating to the cathode insulator 2, and can effectively shield the impact of scattered electrons on the cathode. Therefore, it has the advantage of good reliability. In this embodiment, the material of the metal shell body 1 is an alloy material with iron as the main component, and the main material of the cathode insulator 2 is ceramic.

[0020] In this embodiment, the outer edge of the cathode shielding plate 11 is circular, and a connecting groove 111 is provided on the cathode shielding plate 11 which is adapted to the shape of one end of the cover body 12 near the cathode shielding plate 11 . The end of the cover body 12 near the cathode shielding plate 11 is embedded in the connecting groove 111 .

[0021] Combination Figure 3 As shown, in this embodiment, a convex rib 112 is provided on the end surface of the cathode shielding plate 11 near the cover body 12. In this embodiment, the convex rib 112 extends from the outer edge of the connecting groove 111 to the outer edge of the cathode shielding plate 11. The convex rib 112 in this embodiment can improve the strength and heat dissipation performance of the cathode shielding plate 11.

[0022] In this embodiment, the cover body 12 includes an insulator receiving sleeve 121 and a cathode plate receiving ring 122 which are axially welded together. The proximal ends of the insulator receiving sleeve 121 and the cathode plate receiving ring 122 are respectively provided with connecting end faces 123 which fit each other. The cathode insulator 2 is fixed in the insulator receiving sleeve 121, and the cathode plate receiving ring 122 is connected to the cathode shielding plate 11.

[0023] In this embodiment, the cover body 12 adopts a separately welded insulator receiving sleeve 121 and a cathode plate receiving ring 122. Before welding, the relative position of a pair of connecting end faces 123 can be fine-tuned to achieve fine-tuning of the position of the cathode head in a direction perpendicular to the axial direction. In addition, the metal tube shell body 1 is formed by welding three sections, and each section can be made of different metal materials to take into account economy.

[0024] In this embodiment, a metal connecting ring 21 is fixed to the outside of the cathode insulator 2, the cathode insulator 2 is arranged in the metal connecting ring 21, a sleeve hole 120 adapted to the metal connecting ring 21 is arranged on the open end of the cover body 12 away from the cathode shielding plate 11, and the metal connecting ring 21 is welded to the inner wall of the sleeve hole 120. Before welding, the axial position of the metal connecting ring 21 relative to the sleeve hole 120 can be fine-tuned to achieve fine-tuning of the position of the cathode head in the axial direction.

[0025] Therefore, the spatial position of the cathode head can be fine-tuned to improve the position accuracy of the cathode head and enhance the quality of the radiation.

[0026] The technical principles of the present invention are described above in conjunction with specific embodiments. These descriptions are only for explaining the principles of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without creative work, and these methods will fall within the scope of protection of the present invention.

Claims

1. An X-ray tube cathode insulation assembly, characterized in that: The invention comprises a cathode insulator (2) and a cathode plate (4), wherein the cathode insulator (2) comprises a ceramic body (22) and a metal connector (23) fixed to the end of the ceramic body (22), wherein a connecting ring (41) is provided on the cathode plate (4), wherein the connecting ring (41) is connected to the metal connector (23), and an annular protective cover (5) is fixed on the connecting ring (41), wherein the annular protective cover (5) is arranged radially outside the axial connection position between the ceramic body (22) and the metal connector (23).

2. An X-ray tube cathode insulation assembly according to claim 1, characterized in that: A spacing chamber (50) is provided between the annular protective cover (5), the metal connector (23) and the ceramic body (22) in the radial direction, the spacing chamber (50) comprising a protection chamber (501) and an extension chamber (502) in the axial direction in sequence, the axial position of the protection chamber (501) corresponding to the connection position of the ceramic body (22) and the metal connector (23), the extension chamber (502) being arranged on the outside of the metal connector (23), and the width of the protection chamber (501) being greater than that of the extension chamber (502).

3. An X-ray tube cathode insulation assembly according to claim 2, characterized in that: The annular protective cover (5) is provided with an annular inner edge (51) extending radially inwardly at one end of the corresponding protective cavity (501) away from the extension cavity (502).

4. The X-ray tube cathode insulation assembly according to claim 1, characterized in that: A cathode cover plate (42) is provided at the bottom of the connecting ring (41).

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