Cathode tube shell of X-ray tube

Abstract

The invention relates to the technical field of X-ray tube manufacturing, in particular to a cathode tube shell of an X-ray tube. Comprising a metal tube shell main body, the metal tube shell main body is connected to the end portion of an anode shell, the metal tube shell main body comprises a cover body with two axial ends opened and a cathode shielding plate welded to one end, close to the anode shell, of the cover body, and the cathode shielding plate is arranged between the anode shell and the cover body. And a cathode insulator is fixedly arranged in the metal tube shell main body and is sealed at the opening end, far away from the cathode shielding plate, of the cover body. And ignition cracking caused by the fact that metal steam is easily attached to the inner wall 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 tube shell 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] Glass tube shells are widely used in low-power X-ray tubes. However, with the upgrade of medical X-ray CT equipment, the performance requirements of X-ray tubes are getting higher and higher, requiring X-ray tubes to have higher power and larger heat capacity. One of the problems with glass tube shells is that metal vapor is easily attached to the inner wall, causing sparks and cracks, which in turn leads to the failure of the X-ray tube. 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 shell, which can effectively prevent the inner wall from being easily attached with metal vapor and causing spark cracking.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions: A cathode tube shell of an X-ray tube comprises a metal tube shell body, the metal tube shell body is connected to the end of an anode shell, the metal tube shell body comprises a cover body with openings at both axial ends and a cathode shielding plate welded to one end of the cover body near the anode shell, the cathode shielding plate is arranged between the anode shell and the cover body, a cathode insulator is fixedly arranged in the metal tube shell body, and the cathode insulator is sealed at the open end of the cover body away from the cathode shielding plate.

[0007] Furthermore, in an X-ray tube cathode shell in the present application, a cathode shielding plate is provided with a connecting groove adapted to the shape of one end of the cover body near the cathode shielding plate, and the one end of the cover body near the cathode shielding plate is embedded in the connecting groove.

[0008] Furthermore, in the cathode tube shell of an X-ray tube in the present application, a convex rib is provided on the end surface of the cathode shielding plate near the cover body.

[0009] Furthermore, in the cathode shell of an X-ray tube in the present application, the convex rib extends from the outer edge of the connection groove to the outer edge of the cathode shielding plate. As a preferred solution of the present application, the convex rib in the present application can improve the strength and heat dissipation performance of the cathode shielding plate.

[0010] Furthermore, in the present application, an X-ray tube cathode shell, the cover body includes an insulator storage sleeve and a cathode plate storage ring connected by axial welding, the proximal ends of the insulator storage sleeve and the cathode plate storage ring are respectively provided with connecting end faces that fit each other, the cathode insulator is fixed in the insulator storage sleeve, and the cathode plate storage ring is connected to the cathode shielding plate. As a preferred embodiment of the present application, in the present application, the cover body adopts an insulator storage sleeve and a cathode plate storage ring that are welded separately, and the relative position of a pair of connecting end faces can be fine-tuned before welding to achieve fine-tuning of the position of the cathode head in a direction perpendicular to the axial direction. And the metal shell body is formed by welding three sections, and each section can be made of different metal materials to take into account economy.

[0011] Furthermore, in the present application, a cathode shell of an X-ray tube is provided with a metal connecting ring fixed on the outside of the cathode insulator, the cathode insulator is arranged inside the metal connecting ring, a sleeve hole adapted to the metal connecting ring is provided on the open end of the cover away from the cathode shielding plate, and the metal connecting ring is welded to the inner wall of the sleeve hole. As a preferred solution of the present application, before welding, the axial position of the metal connecting ring relative to the sleeve hole can be fine-tuned to achieve fine-tuning of the position of the cathode head in the axial direction.

[0012] It can be seen from the above technical solution that the present invention has the following beneficial effects: The present invention provides an X-ray tube cathode shell, which can effectively prevent the inner wall from being easily attached with metal vapor and causing spark cracking by adopting a metal shell body, and the cathode shielding plate effectively isolates the metal shell body and the anode shell, preventing the heat of the anode target plate in the anode shell from radiating to the cathode insulator, and can effectively shield the impact of scattered electrons on the cathode. Therefore, it has the advantage of good reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of a cathode tube shell of an X-ray tube in one embodiment of the present application; Figure 2 An exploded view of a cathode shell component of an X-ray tube in one embodiment of the present application; Figure 3 A plan view of a metal tube shell body in an embodiment of the present application; Figure 4 is a schematic structural diagram of a cathode insulator assembly in one embodiment of the present application; Figure 5 This is a schematic diagram of the structure of an annular protective cover in an embodiment of the present application; Figure 6 It is a cross-sectional view of an annular protective cover in one embodiment of the present application.

[0014] 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

[0015] Example 1 Combination Figure 1 to Figure 2 An X-ray tube cathode shell shown in the figure comprises a metal shell body 1, which is connected to the end of an anode shell 3. The metal shell body 1 comprises a cover body 12 with openings at both axial ends and a cathode shielding plate 11 welded to an end of the cover body 12 near the anode shell 3. The cathode shielding plate 11 is arranged between the anode shell 3 and the cover body 12. A cathode insulator 2 is fixedly arranged in the metal shell 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.

[0016] Based on the above structure, the principle of an X-ray tube cathode shell is that the metal shell body 1 can effectively prevent the inner wall from being easily attached to metal vapor and causing spark 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.

[0017] 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 .

[0018] Combination Figure 3As 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] Example 2 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 can eventually form surface flashover and induce sparks in the X-ray tube, causing it to fail.

[0024] Combination Figure 4 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.

[0025] Based on the above structure, a cathode shell of an X-ray tube has the following principle: 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 arranged 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 at the cathode end. The metal connector 23, the connecting ring 41 and the cathode plate 4 are all conductive metals, and the whole forms a cathode high-voltage electrode. The connection position of the ceramic body 22 and the metal connector 23 is placed in the vacuum environment in the cathode 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. The cathode shell of an X-ray tube in this embodiment can effectively avoid the influence of the surface flashover by adding an annular protective cover 5 at this position.

[0026] 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.

[0027] Combination Figure 5 and Figure 6 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.

[0028] 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.

[0029] 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 shell, characterized in that: The invention comprises a metal tube shell body (1), wherein the metal tube shell body (1) is connected to the end of an anode shell (3), wherein the metal tube shell body (1) comprises a cover body (12) with openings at both axial ends and a cathode shielding plate (11) welded to an end of the cover body (12) close to the anode shell (3), wherein the cathode shielding plate (11) is arranged between the anode shell (3) and the cover body (12), and a cathode insulator (2) is fixedly arranged in the metal tube shell body (1), wherein the cathode insulator (2) is sealed to an open end of the cover body (12) away from the cathode shielding plate (11).

2. The X-ray tube cathode shell according to claim 1, characterized in that: The cathode shielding plate (11) is provided with a connection groove (111) that matches the shape of one end of the cover body (12) close to the cathode shielding plate (11), and the one end of the cover body (12) close to the cathode shielding plate (11) is embedded in the connection groove (111).

3. The X-ray tube cathode shell according to claim 2, characterized in that: A convex rib (112) is provided on the end surface of the cathode shielding plate (11) on the side close to the cover body (12).

4. The X-ray tube cathode shell according to claim 3, characterized in that: The convex rib (112) extends from the outer edge of the connecting groove (111) to the outer edge of the cathode shielding plate (11).

5. The X-ray tube cathode shell according to claim 1, characterized in that: The cover body (12) comprises an insulator receiving sleeve (121) and a cathode plate receiving ring (122) connected by axial welding, the insulator receiving sleeve (121) and the cathode plate receiving ring (122) are each provided with a connecting end surface (123) that fits together at adjacent ends, 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).

6. The X-ray tube cathode shell according to claim 1, characterized in that: A metal connecting ring (21) is fixed to the outside of the cathode insulator (2), the cathode insulator (2) is arranged inside the metal connecting ring (21), a sleeve hole (120) adapted to the metal connecting ring (21) is provided on an open end of the cover body (12) away from the cathode shielding plate (11), and the metal connecting ring (21) is connected to the inner wall of the sleeve hole (120) by welding.

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