JP2010080347A - Fixed anode x-ray tube device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed anode X-ray tube device of an excellent withstand voltage characteristic. <P>SOLUTION: This fixed anode X-ray tube device includes a vacuum envelope 2, an anode target 6, a cathode filament 8, an electric power supply part for supplying a high voltage to the anode target, a tube container 15, a high-voltage cable 13, an insulating fixing member 20, and an insulating material 16. The high-voltage cable 13 is led out to an outside of the tube container 15 while penetrated through one part of the tube container 15, and impresses a high voltage to the anode target 6 via the electric power supply part. The fixing member 20 has a through hole 20h inserted with the high-voltage cable 13, and fixes the high-voltage cable. The insulating material 16 envelopes an outer face of the high-voltage cable 13 positioned in an inside of the tube container 15, and is packed in the inside of the tube container 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixed anode type X-ray tube apparatus.

  In general, a fixed anode type X-ray tube apparatus is known as an X-ray tube apparatus (for example, see Patent Documents 1 and 2). The fixed anode X-ray tube apparatus includes a vacuum envelope, an anode target, a cathode filament, a support, a heat radiator, an insulating material, and a high-voltage cable. An output window that transmits X-rays is provided in a flat portion at one end of the vacuum envelope.

  The anode target is disposed inside the vacuum envelope and faces the output window. The cathode filament is disposed inside the vacuum envelope and emits electrons for irradiating the anode target. The support is provided in the vacuum envelope. One end of the support supports the anode target. The other end of the support is joined to the vacuum envelope and protrudes outside the vacuum envelope.

The radiator is connected to the other end of the support. The heat radiating body is for releasing heat generated in the anode target and transmitted to the support. The insulating material is provided around the radiator and inside the radiator. The high voltage cable is for applying a high voltage to the anode target. More specifically, a high voltage is supplied to the anode target from a high voltage cable via a power feeding unit.
JP 2007-42434 A JP-T-2001-504988

  In recent years, due to the oil-free X-ray tube, an insulating resin tends to be used as the insulating material filled outside the vacuum envelope. On the other hand, a high voltage is applied to the anode target by supplying a high voltage from the high voltage cable to the high voltage terminal. For this reason, even if a high voltage is supplied from the high-voltage cable, the insulating material needs to retain the insulating characteristics.

  When an insulating resin is used as the insulating material, the high voltage cable is generally connected to a high voltage power source of the X-ray tube device through the insulating resin. For example, when a high-voltage cable is extended and arranged along the tube axis direction of the X-ray tube, even if a force in the tube axis direction is applied to the high-voltage cable, no force is applied to the insulating resin. There is no problem if the connection is sufficient. However, when a force perpendicular to the tube axis direction is applied to the high-voltage cable, the force is applied to the insulating resin from the high-voltage cable, and the insulating resin may be damaged.

If the insulating resin is damaged, the insulating properties of the X-ray tube are remarkably deteriorated, and in some cases, the X-ray tube may not function. If this problem is solved only by the insulating resin, it is conceivable to increase the hardness of the insulating resin, increase the contact area between the insulating resin and the high-voltage cable, or the like. However, changing the hardness of the resin is not easy. Further, if the contact area is increased, the volume of the X-ray tube is increased, which is detrimental to cost increase and downsizing.
The present invention has been made in view of the above points, and an object of the present invention is to provide a fixed anode X-ray tube apparatus having excellent withstand voltage characteristics.

In order to solve the above problems, a fixed anode X-ray tube apparatus according to an aspect of the present invention includes:
A vacuum envelope formed with an output window that transmits X-rays;
An anode target provided in the vacuum envelope and facing the output window;
A cathode filament that is provided in the vacuum envelope and emits electrons for irradiating the anode target;
A power feeding section for supplying a high voltage to the anode target;
A tube container for housing a part of the vacuum envelope and the power feeding unit;
A high-voltage cable that is connected to the power supply unit, passes through a part of the tube container, is pulled out of the tube container, and applies a high voltage to the anode target through the power supply unit;
An insulative fixing member that is connected to the inside and outside of the tube container and has a through-hole into which the high-voltage cable is inserted, and that fixes the high-voltage cable located in the tube container and the through-hole;
An insulating material that surrounds an outer surface of the high-voltage cable located in the tube container and is filled in the tube container.

  According to the present invention, it is possible to provide a fixed anode X-ray tube device having excellent withstand voltage characteristics.

Hereinafter, a fixed anode X-ray tube apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the fixed anode X-ray tube apparatus includes a vacuum envelope 2, an anode target 6, a support 9, a cathode filament 8, a high voltage terminal 14 as a power feeding unit, and a tube container 15. A heat dissipating member 17, an insulating material 16, a high voltage cable 13, and a fixing member 20.

  The vacuum envelope 2 holds the inside in a vacuum. The vacuum envelope 2 includes a metal envelope 3 on one end side in a direction along the tube axis (hereinafter referred to as a tube axis direction) d, and an insulation outside on the other end which is a portion constituting a high voltage insulating portion. It is configured in combination with the envelope 4.

  The metal envelope 3 has a cylindrical shape whose outer diameter is gradually narrowed, the tip surface is formed flat, and an output window 5 that transmits X-rays is provided in the flat portion. The output window 5 is made of, for example, beryllium (Be) as a material with little X-ray attenuation. The insulating envelope 4 is formed in a cylindrical shape with an insulating material such as electrically insulating ceramics.

  An anode target 6 is disposed inside the vacuum envelope 2 so as to face the output window 5 in the tube axis direction d, and a focusing electrode 7 is disposed outside the anode target 6. A cathode filament 8 is disposed outside. The cathode filament 8 is fixed to the outer peripheral portion of the focusing electrode 7.

  A support body 9 is disposed at the center of the vacuum envelope 2. One end of the support 9 is disposed inside the focusing electrode 7 and supports the anode target 6 at the tip. The other end portion of the support body 9 is exposed to the outside from the other end side of the insulating envelope 4 and is coupled to the insulating envelope 4 in a sealed state by the heat radiating body 17. Here, the other end portion of the support 9 protrudes from the other end side of the insulating envelope 4 and is exposed. One end and the other end of the support 9 are opposed to the tube axis direction d.

  An exhaust pipe 12 for exhausting the inside of the vacuum envelope 2 through an exhaust passage 11 formed inside the support 9 is provided on the end surface of the other end of the support 9. A high voltage terminal 14 to which a high voltage cable 13 for applying a high voltage is connected is provided.

  The heat radiating body 17 is connected to the other end portion of the support 9 and the insulating envelope 4. The radiator 17 is formed in a cylindrical shape. The radiator 17 is formed so that the high-voltage terminal 14 is exposed. The heat radiating body 17 is generally formed of a conductive material such as metal.

The high-voltage cable 13 is located inside the tube container 15, passes through a part of the tube container 15, and is drawn out of the tube container 15. The high voltage cable 13 is connected to the high voltage terminal 14. The high voltage cable 13 is for applying a high voltage to the anode target 6 via the high voltage terminal 14.
Further, the insulating envelope 4 which is a part of the vacuum envelope 2, the other end portion of the support 9 protruding from the insulating envelope 4, the radiator 17 and the high-voltage terminal 14 are accommodated in the tube container 15. ing. The tube container 15 is formed using a metal material, that is, a conductive material, from the viewpoint of robustness for protecting the X-ray tube, ease of molding, good thermal conductivity, potential stability, and the like.

  The insulating fixing member 20 is formed in a cylindrical shape and is fixed to the tube container 15. The fixing member 20 is connected to the inside and the outside of the tube container 15 and has a through hole 20h into which the high-voltage cable 13 is inserted. The fixing member 20 fixes the high voltage cable 13 located in the tube container 15 and the through hole 20h. The material for forming the fixing member 20 is preferably an insulating material such as epoxy, glass epoxy, polybutylene terephthalate, etc., and has good moldability. The fixing member 20 maintains electrical insulation between the tube container 15 and the high-voltage cable 13. The fixing member 20 is solid and hard.

  The tube container 15 is filled with an insulating material 16 which is a potting material such as silicone resin. More specifically, the insulating material 16 is filled between the tube container 15 and the insulating envelope 4 and the radiator 17. The insulating material 16 surrounds the outer surface of the high voltage cable 13 located in the tube container 15.

  When there is a gap between the high voltage cable 13 and the through hole 20h, the insulating material 16 is preferably filled between the high voltage cable 13 and the through hole 20h. In this case, the peripheral edge of the surface of the insulating material 16 is the through hole 20h. It is more preferable that it is surrounded by.

  Although not shown, a cooler for cooling the tube container 15 may be disposed on the outer surface of the tube container 15. That is, heat is generated by the collision of electrons with the anode target 6, and the heat of the anode target 6 is transmitted to the support 9, and the insulation target is removed via the radiator 17 connected to the other end of the support 9. It is diffused and conducted to the envelope 4, the tube container 15, the insulating material 16, and the like. Heat is conducted to the tube container 15.

  Therefore, by using the cooler, heat from the anode target 6 can be released by the cooler that cools the outer surface of the tube container 15. As the cooler, for example, an air-cooled type, a liquid-cooled type, or a heat pipe type can be selected according to the input of the fixed anode X-ray tube device, but an air-cooled type or a heat pipe type that is easy to maintain is preferable. The cooler may be a radiator.

  By configuring the fixed anode type X-ray tube device as described above, it is possible to prevent damage to the insulating material 16 caused by external force applied to the high-voltage cable 13. The reason will be described in detail below. To do.

  A certain distance is required between the high voltage cable 13 to which a high voltage is applied and the conductive tube container 15. As a means for easily taking a certain distance, when the insulating material 16 is resin, a means for taking the distance with the insulating material 16 without providing the fixing member 20 can be considered.

  However, when a force perpendicular to the axis of the high-voltage cable 13 is applied to the high-voltage cable 13, the force is transmitted to the insulating material 16 between the high-voltage cable 13 and the tube container 15. And when the force added is large, the insulating material 16 will be damaged. The breakage of the insulating material 16 means that the insulating characteristics are remarkably deteriorated. For this reason, in some cases, a high voltage cannot be applied, and the function as an X-ray tube may not be achieved.

  Therefore, as described above, the fixing member 20 is fixed to the tube container 15, and the high-voltage cable 13 is passed through the through hole 20h. Thereby, even when a force perpendicular to the axis of the high-voltage cable 13 is applied to the high-voltage cable 13, the force is limited by the fixing member 20, and the force applied to the insulating material 16 is drastically reduced. As a result, even if a force is applied to the high-voltage cable 13, the insulating material 16 is not affected, that is, a robust X-ray tube having excellent withstand voltage characteristics can be obtained.

  According to the fixed anode X-ray tube apparatus configured as described above, the fixed anode X-ray tube apparatus includes the vacuum envelope 2, the anode target 6, the support 9, the cathode filament 8, the heat dissipation. A body 17, a high voltage terminal 14, a tube container 15, an insulating material 16, a high voltage cable 13, and a fixing member 20 are provided.

The fixing member 20 has insulating properties, has a through hole 20h into which the high voltage cable 13 is inserted, and fixes the high voltage cable 13 located in the tube container 15 and in the through hole 20h. For this reason, even when a force perpendicular to the axis of the high-voltage cable 13 is applied to the high-voltage cable 13, the force is limited by the fixing member 20, and the force applied to the insulating material 16 can be drastically reduced. Thereby, even if a force is applied to the high-voltage cable 13, the insulating material 16 is not affected, that is, a robust X-ray tube having excellent withstand voltage characteristics can be obtained.
From the above, it is possible to obtain a fixed anode type X-ray tube device having excellent withstand voltage characteristics.

  Next, a fixed anode X-ray tube apparatus according to another embodiment of the present invention will be described in detail. In this embodiment, other configurations are the same as those of the above-described embodiment, and the same reference numerals are given to the same portions, and detailed description thereof is omitted.

  As shown in FIGS. 2, 3, and 4, the fixed anode X-ray tube apparatus includes a vacuum envelope 2, an anode target 6, a support 9, a cathode filament 8, a joined body 10, and a power supply. A high-voltage terminal 14, a tube container 15, a radiator 17, an insulating material 16, a high-voltage cable 13, and a fixing member 20 are provided.

  The other end of the support 9 is joined to the insulating envelope 4 in a sealed state by a joined body 10. The radiator 17 is formed in a cylindrical shape. The radiator 17 is connected to the support body 9 and the joined body 10. The heat radiating body 17 is connected to the inside and the outside of the tube container 15 and has a through hole 17h into which the high voltage cable 13 is inserted. The radiator 17 is connected to the other end of the support 9 and constitutes a part of the tube container 15.

  The heat radiating body 17 is connected to the inside and the outside of the heat radiating body 17 and has a through portion 17 s extending in a direction perpendicular to the tube axis direction d. The radiator 17 is a ceramic having a high thermal conductivity of 20 W / m · K or higher and a high voltage insulating property of 10 kV / mm or higher. For example, by using aluminum nitride, a high thermal conductivity of 90 W / m · K or higher can be obtained. .

  The fixing member 20 is fixed to the radiator 17. More specifically, the fixing member 20 is fixed to the through hole 17h. The fixing member 20 is located outside the through hole 20h and has a through portion 20p connected to the inside and the outside of the tube container 15. Here, the fixing member 20 has three through portions 20p. The through portion 20p is formed by denting the inner surface of the fixing member 20.

  The insulating material 16 is also filled in the through holes 17h and the through portions 17s. The insulating material 16 is filled through the through portion 20p. The insulating material 16 is connected inside and outside the heat radiating body 17. The peripheral edge of the surface of the insulating material 16 is surrounded by the through hole 20h.

Next, the fixing member 20 is fixed to the heat radiating body 17 to obtain a robust X-ray tube.
The heat radiating body 17 is connected to the joined body 10, passes through the insulating material 16, and is disposed to the outside of the tube container 15 to dissipate heat generated in the X-ray tube. Since the radiator 17 is solid, it is not impossible to fix the high-voltage cable 13 like the fixing member 20. However, since the radiator 17 is a ceramic that has both high thermal conductivity and high voltage insulation, the material is limited. It will come out. In addition, since the radiator 17 has high heat conduction characteristics, the temperature may be transmitted to the high-voltage cable 13 when arranged near the high-voltage cable 13, and it is not a good idea to arrange the radiator 17 near the high-voltage cable 13.

  On the other hand, when the periphery of the high-voltage cable 13 is filled with the insulating resin, the problem that the insulating resin is damaged occurs as described above. Therefore, in such a case, by fixing the fixing member 20 to the heat radiating body 17, a robust X-ray tube as described above can be obtained. In this case, for example, the fixing member 20 can be easily fixed by forming grooves that fit into the radiator 17 and the fixing member 20, that is, the fixing member 20 is a screw and the through hole 17h is a screw hole. Is possible.

Next, the direction in which the insulating material 16 is filled into the tube container 15 will be described.
Although depending on the material characteristics of the insulating material 16, when the insulating resin (potting material) for forming the insulating material 16 is filled, curing gradually starts from the filled portion. Therefore, there is a possibility that the characteristics of the insulating material 16 are slightly different between the initially filled portion and the finally filled portion.

  Basically, the direction in which the insulating resin is filled may be the tube axis direction d or a direction perpendicular to the tube axis direction d. However, when the insulating resin is filled from the direction perpendicular to the tube axis direction d, the filling is asymmetric with respect to the tube axis. If the above-mentioned variation of the insulating resin occurs, the insulation characteristics of the X-ray tube May be affected.

  On the other hand, if the filling is performed from the tube axis direction d, the insulation characteristics in the tube axis direction of the X-ray tube become uniform even if the insulating resin varies, and thus the insulation characteristics of the X-ray tube are hardly affected. Therefore, it is desirable to fill from the tube axis direction d as the filling direction.

  However, when the high-voltage cable 13 extends in the tube axis direction d of the X-ray tube and the fixing member 20 is disposed around the high-voltage cable, the fixing member 20 is disposed. There is a problem that it becomes difficult to fill the insulating resin with the resin. Therefore, the above-mentioned problem can be solved by providing a part of the fixing member 20 with a through part 20p for filling the insulating resin in addition to the through hole 20h through which the high voltage cable 13 passes.

Next, a more effective position of the insulating material 16 for preventing the high voltage cable 13 from damaging the insulating material 16 will be described.
As shown in FIG. 5, when the fixing member 20 is not in contact with the insulating material 16, the force applied to the high-voltage cable 13 is limited by the fixing member 20, but a force may be applied near the surface of the insulating material 16. There is sex. For this reason, there exists a possibility that the insulating material 16 may be damaged. In addition, as shown in FIG. 6, even when the fixing member 20 is completely embedded in the insulating material 16, a force is applied to the surface of the insulating material 16, which may cause the insulating material 16 to be damaged.

  On the other hand, as shown in FIG. 4, when the fixing member 20 is located on the surface of the insulating material 16, the surface of the insulating material 16 is limited by the fixing member 20. For this reason, the fixing member 20 can protect the insulating material 16, and can prevent the insulating material 16 from being damaged by the force applied to the high-voltage cable 13. Therefore, the position of the fixing member 20 in the tube axis direction d is preferably located on the surface of the insulating material 16.

  According to the fixed anode X-ray tube apparatus configured as described above, the fixed anode X-ray tube apparatus includes the vacuum envelope 2, the anode target 6, the support 9, the cathode filament 8, the heat dissipation. The body 17, the joined body 10, the high voltage terminal 14, the tube container 15, the insulating material 16, the high voltage cable 13, and the fixing member 20 are provided.

  The fixing member 20 is insulative, has a through hole 20h into which the high voltage cable 13 is inserted, is fixed to the radiator 17, and is located in the tube container 15, in the through hole 17h and the through hole 20h. The cable 13 is fixed. The peripheral edge of the surface of the insulating material 16 is surrounded by the through hole 20h.

For this reason, even when a force perpendicular to the axis of the high-voltage cable 13 is applied to the high-voltage cable 13, the force is limited by the fixing member 20, and the force applied to the insulating material 16 can be drastically reduced. Thereby, even if a force is applied to the high-voltage cable 13, the insulating material 16 is not affected, that is, a robust X-ray tube having excellent withstand voltage characteristics can be obtained.
From the above, it is possible to obtain a fixed anode type X-ray tube device having excellent withstand voltage characteristics.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
For example, the fixing member 20 may be formed with a gap between the fixing member 20 and the outer surface of the high-voltage cable 13 to the extent that damage to the insulating material 16 can be suppressed. The fixing member 20 may not be fixed to the tube container 15.

Sectional drawing which shows the fixed anode type | mold X-ray tube apparatus which concerns on embodiment of this invention. Sectional drawing which shows the fixed anode type | mold X-ray tube apparatus which concerns on other embodiment of this invention. FIG. 3 is a cross-sectional view of the fixed anode X-ray tube device taken along line AA shown in FIG. 2, and particularly shows a high-voltage cable, an insulating material, a fixing member, and a radiator. Sectional drawing which expands and shows a part of fixed anode type | mold X-ray tube apparatus shown in FIG. Sectional drawing which shows the comparative example of the fixed anode type | mold X-ray tube apparatus shown in FIG. Sectional drawing which shows the other comparative example of the fixed anode type X-ray tube apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Vacuum envelope, 5 ... Output window, 6 ... Anode target, 8 ... Cathode filament, 9 ... Support body, 10 ... Assembly, 13 ... High voltage cable, 14 ... High voltage terminal, 15 ... Tube container, 16 ... Insulation Material: 17 ... Radiator, 17h ... Through hole, 20 ... Fixing member, 20h ... Through hole, 20p ... Through part, d ... Tube axis direction.

Claims (4)

A vacuum envelope formed with an output window that transmits X-rays;
An anode target provided in the vacuum envelope and facing the output window;
A cathode filament that is provided in the vacuum envelope and emits electrons for irradiating the anode target;
A power feeding section for supplying a high voltage to the anode target;
A tube container for housing a part of the vacuum envelope and the power feeding unit;
A high-voltage cable that is connected to the power supply unit, passes through a part of the tube container, is pulled out of the tube container, and applies a high voltage to the anode target through the power supply unit;
An insulative fixing member that is connected to the inside and outside of the tube container and has a through-hole into which the high-voltage cable is inserted, and that fixes the high-voltage cable located in the tube container and the through-hole;
A fixed anode X-ray tube apparatus comprising: an insulating material surrounding an outer surface of the high-voltage cable located in the tube container and filled in the tube container. A support body provided in the vacuum envelope and having one end portion supporting the anode target and the other end portion exposed to the outside of the vacuum envelope;
An insulating heat radiator that is connected to the other end of the support and forms a part of the tube container;
The fixed anode X-ray tube apparatus according to claim 1, wherein the fixing member is fixed to the heat radiating body. The fixing member is located outside the through hole, and has a through portion connected to the inside and the outside of the tube container,
The fixed anode type X-ray tube device according to claim 1, wherein the insulating material is filled through the penetrating portion.   The fixed anode X-ray tube apparatus according to claim 1, wherein a peripheral edge of the surface of the insulating material is surrounded by the through hole.

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