X-ray tube and method for manufacturing the same

Abstract

To provide an x-ray tube and a method for manufacturing the same that can increase the amount of heat dissipation to the outside of an envelope and can facilitate heating of elements inside the envelope during a manufacturing process.SOLUTION: An x-ray tube according to an embodiment includes an envelope capable of maintaining an atmosphere reduced in pressure below atmospheric pressure, a cathode provided inside the envelope and sealed at one end of the envelope, an anode provided inside the envelope and sealed at the other end of the envelope, and a heat dissipation unit provided outside the envelope and joined to the anode. The anode has a rod having one end provided inside the envelope and the other end exposed to the outside of the envelope. The heat dissipation unit is fitted or screwed to the end of the rod exposed to the outside of the envelope.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE FIELD OF THE DISCLOSURE The present invention relates to an x-ray tube and a method for manufacturing an x-ray tube. [Background technology]

[0002] There is an X-ray tube that includes an envelope, a cathode and an anode that are provided inside the envelope. The anode faces the cathode and has a target at the end on the cathode side. The end of the anode opposite the cathode side is exposed from the envelope.

[0003] Here, thermoelectrons generated in a filament provided in the cathode are attracted to the anode and collide with the target. When the thermoelectrons collide with the target, heat is generated along with X-rays. The generated heat is conducted through the anode and released to the outside of the envelope. At this time, if the amount of heat released to the outside is small, the temperature of the target may become too high, causing the target to melt or reducing the dose of X-rays generated.

[0004] In this case, if a heat dissipation member is provided on the end of the anode exposed from the envelope, the amount of heat dissipated to the outside of the envelope can be increased. However, simply providing a heat dissipation member may result in a gap being generated between the anode and the heat dissipation member, which may reduce or vary the amount of heat dissipation.

[0005] In addition, when manufacturing an X-ray tube, it is necessary to release gas adsorbed or occluded on the surface of the elements inside the envelope. Therefore, when the inside of the envelope is evacuated, the elements inside the envelope are heated. At this time, if a heat dissipation member is provided at the end of the anode, the heat of the heated elements is released to the outside through the heat dissipation member. Therefore, it may be difficult to increase the temperature of the elements, or the heating time of the elements may be extended.

[0006] Therefore, there has been a need to develop a technology that can increase the amount of heat dissipated to the outside of the envelope and also facilitate heating of elements inside the envelope during the manufacturing process. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2009-176654 A Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide an X-ray tube and a method for manufacturing an X-ray tube that can increase the amount of heat dissipated to the outside of the envelope and can facilitate heating of elements inside the envelope during the manufacturing process. [Means for solving the problem]

[0009] The X-ray tube according to the embodiment includes an envelope capable of maintaining an atmosphere reduced in pressure below atmospheric pressure, a cathode provided inside the envelope and sealed at one end of the envelope, an anode provided inside the envelope and sealed at the other end of the envelope, and a heat dissipation unit provided outside the envelope and joined to the anode. The anode has a rod having one end provided inside the envelope and the other end exposed to the outside of the envelope. The heat dissipation unit is fitted or screwed to the end of the rod exposed to the outside of the envelope. Effect of the Invention

[0010] According to an embodiment of the present invention, it is possible to provide an X-ray tube and a method for manufacturing an X-ray tube that can increase the amount of heat dissipated to the outside of the envelope and can facilitate heating of elements inside the envelope during the manufacturing process. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view illustrating an X-ray tube according to an embodiment of the present invention. [Diagram 2]10A and 10B are schematic cross-sectional views illustrating a heat dissipation portion according to a comparative example. [Diagram 3] 11A to 11C are schematic cross-sectional views illustrating a rod according to another embodiment. [Figure 4] 11A to 11C are schematic cross-sectional views illustrating a heat dissipation portion according to another embodiment. [Diagram 5] 13A and 13B are schematic cross-sectional views illustrating a heat dissipation portion according to another embodiment. [Figure 6] 11A and 11B are schematic cross-sectional views illustrating screw connections between a rod and a heat dissipation portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate. (X-ray tube) The X-ray tube 1 according to this embodiment can be provided in, for example, an X-ray inspection device used for non-destructive inspection, etc., or an X-ray image diagnostic device used for medical diagnosis, etc. However, the uses of the X-ray tube 1 are not limited to these.

[0013] FIG. 1 is a schematic cross-sectional view illustrating an X-ray tube 1 according to the present embodiment. As shown in FIG. 1, the X-ray tube 1 may be a fixed anode X-ray tube. The X-ray tube 1 includes, for example, an envelope 10, a cathode 20, an anode 30, and a heat sink 40.

[0014] The envelope 10 is capable of maintaining an atmosphere (also referred to as a vacuum state) that is reduced in pressure below atmospheric pressure. The envelope 10 has a tubular (for example, cylindrical) shape. The envelope 10 extends along the central axis 1a of the X-ray tube 1. One end of the envelope 10 is closed, and the other end is open. An exhaust pipe 11 can be provided integrally with the closed end of the envelope 10. The exhaust pipe 11 is used when exhausting the inside of the envelope 10. After the inside of the envelope 10 is exhausted, the exhaust pipe 11 is burned off, thereby sealing the inside of the envelope 10 so that it is airtight. The exhaust pipe 11 can also be provided on the side of the envelope 10. The envelope 10 is formed using a glass material such as borosilicate glass.

[0015] The cathode 20 is provided inside the envelope 10 and is sealed at one end of the envelope 10 (the closed end of the envelope 10). The cathode 20 includes, for example, a filament 21, a filament terminal 22, a connection pin 23, a cover 24, and a stand 25. The filament 21, the filament terminal 22, and the cover 24 are provided inside the envelope 10.

[0016] The filament 21 is heated by energization and generates thermoelectrons 26. The filament 21 has, for example, a coil-shaped portion 21a and a pair of leads 21b. The coil-shaped portion 21a and the pair of leads 21b are integrally formed. The coil-shaped portion 21a extends in a direction perpendicular to the central axis 1a of the X-ray tube 1. Each of the pair of leads 21b is provided at an end of the coil-shaped portion 21a. Each of the pair of leads 21b extends in a direction along the central axis 1a of the X-ray tube 1.

[0017] A pair of filament terminals 22 are provided. The pair of filament terminals 22 are, for example, pin-shaped and extend in a direction along the central axis 1a of the X-ray tube 1. An end of the filament terminal 22 on the anode 30 side holds the lead 21b of the filament 21 and is electrically connected to the lead 21b.

[0018] A pair of connection pins 23 are provided. The pair of connection pins 23 extend, for example, in a direction along the central axis 1a of the X-ray tube 1. The pair of connection pins 23 are hermetically fused to the closed end of the envelope 10. The end of the connection pin 23 on the anode 30 side is provided inside the envelope 10 and is electrically connected to the filament terminal 22. The end of the connection pin 23 opposite to the anode 30 side is exposed to the outside of the envelope 10.

[0019] The cover 24 has, for example, a cylindrical shape and extends in a direction along the central axis 1a of the X-ray tube 1. The filament 21 and the target 32 ​​of the anode 30 are provided inside the cover 24. That is, the cover 24 surrounds the filament 21 and the target 32 ​​of the anode 30. In the direction along the central axis 1a of the X-ray tube 1, the filament 21 faces the target 32. An X-ray exit port 24a is provided on a side surface of the cover 24.

[0020] The cover 24 is formed using a metal such as stainless steel. The cover 24 has, for example, a disk-shaped portion having a function of a focusing electrode (Wehnelt electrode) and a cylindrical portion having a function of preventing the generated X-rays from entering an unintended area of ​​the envelope 10. Depending on the application of the X-ray tube 1, the cover 24 may surround the filament 21 and the target 32 ​​may be exposed from the cover 24. That is, there may be cases where the cylindrical portion is not provided. In this case, the cover 24 has a function of a focusing electrode. However, if the cover 24 also surrounds the target 32, it is possible to prevent the generated X-rays from entering an unintended area of ​​the envelope 10. Therefore, it is possible to prevent the envelope 10 from deteriorating over time.

[0021] For example, a pair of stands 25 may be provided. The pair of stands 25 may be, for example, pin-shaped and extend in a direction along the central axis 1a of the X-ray tube 1. The pair of stands 25 are hermetically fused to the closed ends of the envelope 10. The number of stands 25 may be changed as appropriate. It is sufficient that at least one stand 25 is provided. An end of the stand 25 on the anode 30 side is provided inside the envelope 10 and connected to the cover 24. An end of the stand 25 opposite the anode 30 side is exposed to the outside of the envelope 10.

[0022] The anode 30 is provided inside the envelope 10 and is sealed at the other end of the envelope 10 (the open end of the envelope 10). The anode 30 includes, for example, a rod 31 and a target 32 ​​.

[0023] The rod 31 is, for example, columnar and extends in a direction along the central axis 1a of the X-ray tube 1. One end of the rod 31 (the end on the cathode 20 side) is provided inside the envelope 10, and the other end (the end opposite to the cathode 20 side) is exposed to the outside of the envelope 10. The rod 31 is provided at an open end of the envelope 10 via, for example, a cylindrical connecting member 33. One end of the connecting member 33 is airtightly connected to the rod 31. The other end of the connecting member 33 is airtightly fused to the open end of the envelope 10. Therefore, the atmosphere inside the envelope 10 can be maintained at a reduced pressure lower than atmospheric pressure.

[0024] The end of the rod 31 on the cathode 20 side is inclined with respect to the central axis 1a of the X-ray tube 1. In the direction along the central axis 1a of the X-ray tube 1, the end of the rod 31 on the cathode 20 side faces the filament 21 with a predetermined distance therebetween.

[0025] A female screw 31a is provided on the end face of the rod 31 opposite to the cathode 20. The female screw 31a may be provided on the heat dissipation portion 40 described later, or may be provided on the rod 31 and the heat dissipation portion 40.

[0026] The female screw 31a can be used when installing the X-ray tube 1. For example, the X-ray tube 1 is installed inside a container that contains insulating oil or the like. Therefore, if the female screw 31a is provided, the X-ray tube 1 can be installed inside the container by attaching the female screw 31a to a male screw provided inside the container. Note that the X-ray tube 1 may be provided with a male screw, and the container may be provided with a female screw. Depending on the method of installing the X-ray tube 1, the female screw 31a or the male screw may be omitted.

[0027] The rod 31 is formed, for example, using a material having high electrical conductivity and high thermal conductivity, and may be formed, for example, using a metal such as copper or a copper alloy.

[0028] The target 32 ​​has, for example, a disk shape and is provided inside the envelope 10. The target 32 ​​is provided at the end of the rod 31 on the cathode 20 side. Therefore, the target 32 ​​is inclined with respect to the central axis 1a of the X-ray tube 1.

[0029] The target 32 ​​includes a material that generates X-rays when collided with the thermal electrons 26. The target 32 ​​includes, for example, at least one of Rh (rhodium), W (tungsten), molybdenum (Mo), and chromium (Cr).

[0030] Here, when a power supply provided outside the X-ray tube 1 applies a negative voltage to the filament 21 via the connection pin 23 of the cathode 20, the filament 21 is heated and thermoelectrons 26 are generated as shown in FIG. 1. Also, when a power supply provided outside the X-ray tube 1 applies a positive voltage (tube voltage) to the target 32 ​​via the rod 31 of the anode 30, the thermoelectrons 26 are accelerated due to the potential difference between the filament 21 and the target 32, and the accelerated thermoelectrons 26 (electron beam) collide with the target 32. X-rays are generated when the thermoelectrons 26 collide with the target 32. Since the target 32 ​​is inclined with respect to the central axis 1a of the X-ray tube 1, the generated X-rays move in a direction intersecting the direction in which the central axis 1a of the X-ray tube 1 extends, pass through the side surface of the envelope 10, and are radiated to the outside.

[0031] Furthermore, most of the energy of the thermoelectrons 26 colliding with the target 32 ​​is converted into heat. The converted heat is conducted through the rod 31 and is released from the vicinity of the end of the rod 31 exposed to the outside of the envelope 10 to the insulating oil or the like outside the envelope 10.

[0032] In this case, if the amount of heat dissipated from the portion of the envelope 10 exposed to the outside is small, the temperature of the target 32 ​​may become too high, causing the target 32 ​​to melt or reducing the amount of X-rays generated.

[0033] For example, if a heat dissipation portion is provided at the end of the rod 31 that is exposed to the outside of the envelope 10, the amount of heat dissipated to the outside of the envelope 10 can be increased. FIG. 2 is a schematic cross-sectional view illustrating a heat dissipation portion 140 according to a comparative example. 2, the heat dissipation part 140 has a columnar shape and is provided at an end of the rod 31 that is exposed to the outside of the enclosure 10. The heat dissipation part 140 has a hole 140a that opens to one end face. The rod 31 is provided inside the hole 140a. A gap 140b is provided between the inner wall of the hole 140a and the rod 31.

[0034] In this case, if there is a gas such as air or a liquid such as insulating oil inside the gap 140b, it becomes difficult for heat to be transferred from the rod 31 to the heat dissipation unit 140. For this reason, a layer 140c containing a low melting point alloy such as solder or silver solder is provided inside the gap 140b. If the layer 140c containing a low melting point alloy is provided inside the gap 140b, heat is easily transferred from the rod 31 to the heat dissipation unit 140.

[0035] However, as shown in FIG. 2, it is difficult to provide layer 140c in the entire area of ​​gap 140b. It is also difficult to prevent the size of the area where layer 140c is provided from varying. Therefore, the amount of heat dissipated to the outside of envelope 10 may vary for each of the multiple X-ray tubes. If the amount of heat dissipated to the outside of envelope 10 varies, it may become impossible to prevent target 32 ​​from melting or the amount of X-rays from being reduced.

[0036] Therefore, the heat dissipation portion 40 according to this embodiment is fitted or screwed to the end of the rod 31 exposed to the outside of the envelope 10. For example, the heat dissipation part 40 has a columnar shape and has a hole 40a that opens on one end face. The rod 31 is fitted inside the hole 40a. For example, the heat dissipation part 40 can be press-fitted into the end of the rod 31, can be shrink-fitted into the end of the rod 31, or can be cold-fitted into the end of the rod 31. In this case, it is preferable that the heat dissipation part 40 is shrink-fitted into the end of the rod 31. If the heat dissipation part 40 is shrink-fitted into the end of the rod 31, the inner wall of the hole 40a and the side of the rod 31 can be more reliably in close contact with each other. Therefore, heat is easily transferred from the rod 31 to the heat dissipation part 40, so that the amount of heat dissipated to the outside of the enclosure 10 can be increased and the variation in the amount of heat dissipation can be suppressed. In addition, since the tightening margin can be increased, the joining force between the heat dissipation part 40 and the rod 31 can be increased.

[0037] The heat dissipation portion 40 is made of a material having high thermal conductivity, for example, aluminum or an aluminum alloy.

[0038] As described above, the heat generated when the thermoelectrons 26 collide with the target 32 ​​is radiated to the outside of the envelope 10 via the rod 31 and the heat dissipation section 40. Therefore, when the X-ray tube 1 is operated, the heat dissipation section 40 is heated, and there is a risk that the bonding strength between the rod 31 and the heat dissipation section 40 becomes too weak. If the bonding strength between the rod 31 and the heat dissipation section 40 becomes too weak, there is a risk that heat will not be easily transferred from the rod 31 to the heat dissipation section 40, or that the position of the heat dissipation section 40 will shift.

[0039] FIG. 3 is a schematic cross-sectional view illustrating a rod 31b according to another embodiment. 3, a recess 31b1 may be provided on the side surface of the rod 31b. At least one recess 31b1 may be provided. The recess 31b1 may be provided near an end of the rod 31b that is exposed to the outside of the envelope 10. For example, the recess 31b1 may be provided in an area on the side surface of the rod 31b where the heat dissipation part 40 is fitted.

[0040] The recess 31b1 may be, for example, a groove formed by cutting. For example, the recess 31b1 may be a screw groove. Alternatively, the recess 31b1 may be a depression formed at random positions by blasting.

[0041] If the recess 31b1 is provided on the side surface of the rod 31b, when the heat dissipation part 40 is fitted to the rod 31b, the inner wall of the hole 40a of the heat dissipation part 40 can be caused to bite into the inside of the recess 31b1. In this case, if the heat dissipation part 40 is made of a soft material such as an aluminum alloy, it becomes easy to cause the inner wall of the hole 40a of the heat dissipation part 40 to bite into the inside of the recess 31b1.

[0042] If the inner wall of the hole 40a of the heat dissipation part 40 bites into the inside of the recess 31b1, an anchor effect can be exerted, and therefore the bonding strength between the heat dissipation part 40 and the rod 31b can be increased. If the bonding strength between the heat dissipation part 40 and the rod 31b is increased, it is possible to suppress the heat from being difficult to transfer from the rod 31b to the heat dissipation part 40 and the position of the heat dissipation part 40 from shifting when the X-ray tube 1 is operated.

[0043] In this case, the joining strength between the heat dissipation unit 40 and the rod 31b can be adjusted by the opening size, depth, number, etc. of the recess 31b1. Therefore, the opening size, depth, number, etc. of the recess 31b1 can be appropriately changed depending on the temperature of the heat dissipation unit 40, the tightening margin of the fitting, the material of the heat dissipation unit 40, the material of the rod 31b, etc.

[0044] FIG. 4 is a schematic cross-sectional view illustrating a heat dissipation portion 40b according to another embodiment. 4, a recess 40b1 may be provided on the inner wall of a hole 40ba of the heat dissipation portion 40b into which the rod 31 is fitted. At least one recess 40b1 may be provided.

[0045] The recess 40b1 may be, for example, a groove formed by cutting. For example, the recess 40b1 may be a screw groove. Alternatively, the recess 40b1 may be a depression formed at random positions by blasting.

[0046] If the recess 40b1 is provided on the inner wall of the hole 40ba, when the heat dissipation part 40b is fitted to the rod 31, the side surface of the rod 31 can be inserted into the recess 40b1. This allows an anchor effect to be exerted, and the joining strength between the heat dissipation part 40b and the rod 31 to be increased. As a result, similar to the case of the rod 31b described above, it is possible to prevent heat from being difficult to transfer from the rod 31 to the heat dissipation part 40b and to prevent the position of the heat dissipation part 40b from shifting when the X-ray tube 1 is operated.

[0047] In this case, the opening size, depth, number, etc. of the recesses 40b1 can be used to adjust the joining strength between the heat dissipation portion 40b and the rod 31. Therefore, the opening size, depth, number, etc. of the recesses 40b1 can be appropriately changed depending on the temperature of the heat dissipation portion 40b, the fitting interference, the material of the heat dissipation portion 40b, the material of the rod 31, etc.

[0048] In the above, the recess is provided on the side surface of the rod or the inner wall of the hole of the heat dissipation part, but the recess can also be provided on the side surface of the rod and the inner wall of the hole of the heat dissipation part. In other words, the recess can be provided on at least one of the side surface of the rod and the inner wall of the hole of the heat dissipation part.

[0049] In the above, a concave portion is provided on at least one of the side surface of the rod and the inner wall of the hole of the heat dissipation part, but a convex portion can be provided on at least one of the side surface of the rod and the inner wall of the hole of the heat dissipation part. In this case, the convex portion bites into the surface of the mating part with which it is fitted. In this way, an anchor effect can be exerted, and the joining force between the heat dissipation part and the rod can be increased.

[0050] In this case, if the protruding dimension (height) of the convex portion is made too large, a gap may occur between the side surface of the rod and the inner wall of the hole in the heat dissipation portion, so it is preferable that the protruding dimension of the convex portion is 0.1 mm or less.

[0051] As described above, when the heat dissipation part is fitted to the end of the rod, at the contact portion between the heat dissipation part and the rod, a part of one can be made to bite into the other.

[0052] 5(a) and (b) are schematic cross-sectional views illustrating heat dissipation portions 41 and 42 according to other embodiments. 5(a) and (b), the heat dissipation parts 41 and 42 have a main body 41a and fins 41b. The main body 41a can be the same as the heat dissipation part 40 having the recess 40a described above. That is, the heat dissipation parts 41 and 42 can be the heat dissipation part 40 further provided with fins 41b. Also, like the heat dissipation part 40b described above, a recess 40b1 can be provided on the inner wall of the hole 40ba.

[0053] The fin 41b is plate-shaped and provided on the side surface of the main body 41a. The fin 41b extends in a direction intersecting with the side surface of the main body 41a. At least one fin 41b may be provided. When multiple fins 41b are provided, the multiple fins 41b may be arranged side by side along the extension direction of the main body 41a.

[0054] In this case, the amount of heat dissipated to the outside of the envelope 10 can be adjusted by at least one of the size (surface area) and the number of the fins 41b. Therefore, the size (surface area) and the number of the fins 41b can be appropriately changed depending on the application (amount of heat) of the X-ray tube 1. The size (surface area) and the number of the fins 41b can be appropriately determined by performing experiments and simulations.

[0055] Furthermore, if the fins 41b are provided, the amount of heat dissipated to the outside of the envelope 10 can be increased, but the manufacturing cost increases. Therefore, depending on the application (amount of heat) of the X-ray tube 1, the fins 41b may be omitted.

[0056] The heat sink can also be screwed onto the end of the rod that is exposed outside the envelope 10 . FIG. 6 is a schematic cross-sectional view illustrating the screw connection between the rod 31c and the heat dissipation portion 43. As shown in FIG. As shown in FIG. 6, a male screw 31ca can be provided on the side surface of the rod 31c, and a female screw 43a can be provided on the inner wall of the hole of the heat dissipation part 43. That is, the heat dissipation part 43 can be screwed into the end of the rod 31c exposed to the outside of the enclosure 10. In this case, a gap may be generated between the male screw 31ca and the female screw 43a. Therefore, it is preferable to provide at least one of a layer 44 containing thermally conductive grease and a layer 45 containing a component of a thermally conductive adhesive (a layer formed by hardening the thermally conductive adhesive) between the male screw 31ca and the female screw 43a. For example, at least one of a thermally conductive grease and a thermally conductive adhesive may be applied to at least one of the male screw 31ca and the female screw 43a, and then the heat dissipation part 43 may be screwed into the rod 31c.

[0057] In this way, the rod 31c and the heat dissipation section 43 can be joined more easily than in the above-mentioned joint by fitting. Therefore, the manufacturing cost can be reduced. However, the heat is transferred from the rod to the heat dissipation section more easily in the above-mentioned joint by fitting. Therefore, the joining method can be appropriately selected according to the use (heat generation) of the X-ray tube 1. For example, when the temperature of the heat dissipation section is 100°C or less, a joining method using male screws, female screws, and thermally conductive grease (or thermally conductive adhesive) can be selected.

[0058] (X-ray tube manufacturing method) Next, a method for manufacturing the X-ray tube 1 according to the present embodiment will be described. In the following, a method for manufacturing the X-ray tube 1 having the configuration illustrated in FIG. 1 will be described as an example.

[0059] A method for manufacturing the X-ray tube 1 according to the present embodiment may include, for example, the following steps. A step of manufacturing a cathode 20 having a filament 21, a filament terminal 22, a connecting pin 23, a cover 24, and a stand 25. Producing an anode 30 having a rod 31 and a target 32 ​​. A step of sealing the cathode 20 at one end of the envelope 10. A step of sealing the anode 30 to the other end of the envelope 10 via the connection member 33. An exhaust process in which the inside of the envelope 10 is evacuated through an exhaust pipe 11 connected to the envelope 10 and elements inside the envelope 10 are heated to release gas. A process of burning off the exhaust pipe 11 to seal the inside of the envelope 10 airtight. Since known techniques can be applied to the above steps, detailed explanations will be omitted.

[0060] In the above-mentioned exhaust step, the anode 30 and the like are heated, for example, to about 500° C. in order to release gas adsorbed or occluded on the surfaces of the elements inside the envelope 10. Therefore, if the heat dissipation unit 40 is joined to the anode 30, there is a risk that the heat dissipation from the heat dissipation unit 40 may make it difficult to increase the temperature of the anode 30 and the like, or that the heating time of the anode 30 and the like may become longer.

[0061] Therefore, the manufacturing method of the X-ray tube 1 according to the present embodiment includes a step of fitting or screwing the heat dissipation part 40 to the rod 31 of the anode 30 exposed from the end of the sealed envelope 10. That is, in the manufacturing method of the X-ray tube 1 according to the present embodiment, after the evacuation step, the heat dissipation part 40 is fitted or screwed to the rod 31 of the anode 30 exposed from the end of the envelope 10.

[0062] As described above, when the rod 31 and the heat dissipating portion 40 are joined by fitting, the fitting can be performed by, for example, press fitting, shrink fitting, or cold fitting. However, as described above, it is preferable to fit the heat dissipation part 40 to the rod 31 by shrink fitting. In this way, the rod 31 and the heat dissipation part 40 can be more reliably attached to each other. This makes it easier for heat to be transferred from the rod 31 to the heat dissipation part 40, thereby increasing the amount of heat dissipated to the outside of the enclosure 10 and suppressing variations in the amount of heat dissipation. In addition, since the tightening margin can be increased, the joining force between the heat dissipation part 40 and the rod 31 can be increased. The same applies to the heat dissipation sections 40b, 41, and 42 described above.

[0063] Furthermore, as illustrated in FIG. 3, when recesses 31b1 are provided on the side surfaces of rods 31b of anode 30, the inner walls of holes 40a of heat dissipation portion 40 can be caused to fit into recesses 31b1. Furthermore, as illustrated in FIG. 4, when a recess 40b1 is provided on the inner wall of the hole 40ba of the heat dissipation portion 40b, the side surface of the rod 31 of the anode 30 can be inserted into the recess 40b1. As a result, the bonding strength between the heat dissipation part and the rod can be increased, thereby preventing heat from being difficult to transfer from the rod to the heat dissipation part and preventing the position of the heat dissipation part from shifting when the X-ray tube 1 is operated.

[0064] 6, the heat dissipation unit 43 can be screwed to the rod 31c exposed from the end of the enclosure 10. In this case, at least one of thermally conductive grease and thermally conductive adhesive is applied to at least one of the male thread 31ca of the rod 31c and the female thread 43a of the heat dissipation unit 43, and then the heat dissipation unit 43 can be screwed onto the rod 31c.

[0065] Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples and are not intended to limit the scope of the invention. Any design modifications made by a person skilled in the art to the above-described embodiments are also included within the scope of the present invention as long as they include the features of the present invention.

[0066] For example, the shape, size, material, arrangement, and the like of each element included in the X-ray tube 1 are not limited to those exemplified, and can be changed as appropriate. Furthermore, the elements of each of the above-described embodiments can be combined to the greatest extent possible, and combinations of these are also included within the scope of the present invention as long as they include the features of the present invention.

[0067] Below, additional notes regarding the above-described embodiment are given.

[0068] (Appendix 1) an envelope capable of maintaining an atmosphere at a reduced pressure below atmospheric pressure; a cathode provided inside the envelope and sealed at one end of the envelope; an anode provided inside the envelope and sealed at the other end of the envelope; a heat sink provided outside the envelope and joined to the anode; Equipped with the anode has a rod having one end provided inside the envelope and the other end exposed to the outside of the envelope; The heat sink is fitted or screwed to the end of the rod exposed outside the envelope.

[0069] (Appendix 2) The heat sink is fitted to the end of the rod, 2. The X-ray tube according to claim 1, wherein at a contact portion between the heat sink and the rod, a portion of one of the heat sink and the rod is embedded in the other.

[0070] (Appendix 3) 3. The X-ray tube of claim 1, wherein the heat dissipation portion is shrink-fitted to the end of the rod.

[0071] (Appendix 4) the heat sink is threadedly connected to the end of the rod; 2. The X-ray tube according to claim 1, wherein at least one of a layer containing thermally conductive grease and a layer containing a component of a thermally conductive adhesive is provided between the male thread and the female thread.

[0072] (Appendix 5) 5. The X-ray tube according to claim 1, wherein the heat dissipation portion further includes a plate-shaped fin.

[0073] (Appendix 6) A method for producing an X-ray tube according to any one of claims 1 to 5, an exhaust step of evacuating the inside of the envelope through an exhaust pipe connected to the envelope and heating elements inside the envelope to release gas; a step of burning off the exhaust pipe to seal the inside of the envelope so that the inside of the envelope is airtight; a step of fitting or screwing a heat sink onto an anode rod exposed from an end of the sealed envelope; A method for manufacturing an X-ray tube comprising the steps of:

[0074] (Appendix 7) 7. The method for manufacturing an X-ray tube according to claim 6, wherein in the step of fitting the heat dissipation portion, the heat dissipation portion is fitted onto the rod by shrink fitting.

[0075] (Appendix 8) 7. The method for manufacturing an X-ray tube according to claim 6, wherein in the step of screwing the heat dissipation portion, at least one of a thermally conductive grease and a thermally conductive adhesive is applied to at least one of a male thread and a female thread, and the heat dissipation portion is screwed onto the rod. [Explanation of symbols]

[0076] 1 X-ray tube, 1a central axis, 10 envelope, 20 cathode, 30 anode, 31 rod, 31c rod, 31ca male screw, 32 target, 40 heat sink, 40a hole, 40b heat sink, 40ba hole, 40b1 recess, 41 heat sink, 41b fin, 42 heat sink, 43 heat sink, 43a female screw, 44 layer, 45 layer

Claims

1. an envelope capable of maintaining an atmosphere at a reduced pressure below atmospheric pressure; a cathode provided inside the envelope and sealed at one end of the envelope; an anode provided inside the envelope and sealed at the other end of the envelope; a heat sink provided outside the envelope and joined to the anode; Equipped with the anode has a rod having one end provided inside the envelope and the other end exposed to the outside of the envelope; The heat sink is fitted or screwed to the end of the rod exposed outside the envelope.

2. The heat sink is fitted to the end of the rod, 2. The X-ray tube according to claim 1, wherein a portion of one of said heat sink and said rod is embedded in the other at a contact portion between said heat sink and said rod.

3. 3. The X-ray tube of claim 1, wherein the heat sink is shrink-fitted to the end of the rod.

4. the heat sink is threadedly connected to the end of the rod; 2. The X-ray tube according to claim 1, further comprising at least one of a layer containing thermally conductive grease and a layer containing a component of a thermally conductive adhesive, provided between the male thread and the female thread.

5. 3. The X-ray tube according to claim 1, wherein the heat dissipation portion further comprises a plate-shaped fin.

6. 2. A method for manufacturing an X-ray tube according to claim 1, comprising the steps of: an exhaust step of evacuating the inside of the envelope through an exhaust pipe connected to the envelope and heating elements inside the envelope to release gas; a step of burning off the exhaust pipe to seal the inside of the envelope so that the inside of the envelope is airtight; a step of fitting or screwing a heat sink onto an anode rod exposed from an end of the sealed envelope; A method for manufacturing an X-ray tube comprising the steps of:

7. 7. The method of manufacturing an X-ray tube according to claim 6, wherein in the step of fitting the heat radiating portion, the heat radiating portion is fitted onto the rod by shrink fitting.

8. 7. The method for manufacturing an X-ray tube according to claim 6, wherein in the step of screwing the heat dissipation portion, at least one of a thermally conductive grease and a thermally conductive adhesive is applied to at least one of a male thread and a female thread, and the heat dissipation portion is screwed onto the rod.

Images