X-ray generating device

Abstract

The X-ray generating device includes: an X-ray tube that generates X-rays; an X-ray tube housing part which houses at least a portion of the X-ray tube and in which an insulating liquid is sealed; a surrounding part that surrounds the X-ray tube housing part when viewed from the tube axis direction of the X-ray tube; a gas flow generation unit that causes a gas to flow through a surrounding space defined between the X-ray tube housing unit and the surrounding unit; and an X-ray shielding part which is provided on the inner surface or the outer surface of the surrounding part and is made of a material having higher X-ray shielding performance than the X-ray tube housing part and the surrounding part.

Description

[0001] This application is filed on February 18, 2019 、Application No. 201980024612.5 、The name of the invention is X-ray Generator A divisional application for a patent application. Technical Field

[0002] One aspect of the present invention relates to an X-ray generating device. Background Art

[0003] In an X-ray source (X-ray generating device) including a high-output X-ray tube, it is necessary to take into account both the cooling of the X-ray tube and the shielding of leaked X-rays (X-rays from unexpected emission paths). As structures for cooling such X-ray tubes or shielding of leaked X-rays, structures such as those described in Patent Documents 1 to 3 are known. In the X-ray generating device described in Patent Document 1, a heat dissipation ventilation path and an X-ray shielding component are provided on one side of a housing that accommodates the X-ray tube. In the X-ray source described in Patent Document 2, an air supply fan unit is provided on the side of the X-ray tube storage portion. In the X-ray tube device described in Patent Document 3, a housing including an X-ray shielding material covers the housing that accommodates the X-ray tube, so that a cooling medium flows in the housing.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent document 1: Japanese Patent No. 4080256.

[0007] Patent document 2: Japanese Patent Application Publication No. 2015-32512.

[0008] Patent document 3: Japanese Patent No. 4889979. Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] In the structure described in the above-mentioned patent document 1, the cooling of the X-ray tube and the shielding of the leaked X-rays are performed only on one side of the X-ray tube storage part (shell), and the cooling of the X-ray tube storage part and the shielding of the leaked X-rays may be insufficient. In the structure described in the above-mentioned patent document 2, the shell covering the shell is formed by an X-ray shielding material. That is, the shell itself has X-ray shielding performance. Therefore, in order to ensure the necessary mechanical strength for functioning as a shell, the material constituting the shell may need to be more than the amount necessary to obtain the required X-ray shielding performance. In addition, the problem of the shell becoming heavier may arise. In addition, in the structure described in the above-mentioned patent document 3, although the X-ray tube storage part is cooled by the air supply fan unit, since there is no structure for shielding the X-rays leaking around the X-ray tube storage part, there is room for further improvement in the cooling of the X-ray tube storage part and the shielding of the leaked X-rays.

[0011] Therefore, an object of one embodiment of the present invention is to provide an X-ray generating device that can effectively achieve both cooling of an X-ray tube and shielding of leaked X-rays.

[0012] Technical solutions to the problem

[0013] An X-ray generating device according to one embodiment of the present invention comprises: an X-ray tube for generating X-rays; an X-ray tube housing portion which houses at least a portion of the X-ray tube and is sealed with an insulating liquid; an enclosure portion which surrounds the X-ray tube housing portion when viewed from the axial direction of the X-ray tube; an airflow generating portion which allows gas to flow in an enclosure defined between the X-ray tube housing portion and the enclosure portion; and an X-ray shielding portion which is arranged on the inner surface or the outer surface of the enclosure portion and is made of a material having a higher X-ray shielding performance than the X-ray tube housing portion and the enclosure portion.

[0014] Generally speaking, materials that represent good properties as X-ray shielding materials often have low thermal conductivity. Therefore, when an X-ray tube housing is formed of an X-ray shielding material, there is a problem that the heat dissipation of the X-ray tube housing is deteriorated, and the cooling efficiency of the X-ray tube is reduced. On the other hand, when an enclosure is formed of an X-ray shielding material, it is difficult to have both the function of shielding leaked X-rays and the function of serving as a shell for the X-ray tube housing. In particular, if a self-supporting enclosure is formed only by a material having X-ray shielding performance, there is a possibility that the material must be more than the necessary amount for obtaining the required X-ray shielding performance in order to ensure the strength of the enclosure. In particular, there is a problem that the enclosure becomes heavier. In contrast, according to an X-ray generator of one embodiment of the present invention, the heat generated by the X-ray tube is absorbed by the insulating liquid sealed in the X-ray tube housing and transferred to the X-ray tube housing. In addition, the X-ray tube housing is cooled by the gas flowing through the enclosure space formed between the X-ray tube housing and the enclosure, so that the X-ray tube can be effectively cooled. Furthermore, by providing the X-ray shielding portion as a component different from the surrounding portion on the inner surface or outer surface of the surrounding portion, X-rays leaking around the X-ray generator can be appropriately shielded. Thus, according to the above-mentioned X-ray generator, it is possible to effectively take into account both the cooling of the X-ray tube and the shielding of the leaked X-rays.

[0015] The X-ray tube housing may be formed of a metal material having a higher thermal conductivity than the surrounding portion and the X-ray shielding portion. According to this configuration, the heat generated by the X-ray tube can be effectively dissipated.

[0016] The X-ray shielding portion may be provided on the inner surface of the surrounding portion. According to this configuration, compared with the case where the X-ray shielding portion is provided on the outer surface of the surrounding portion, it is possible to prevent the X-ray shielding portion from peeling off due to contact from the outside.

[0017] The X-ray generating device may further include a storage portion defining a storage space capable of storing the airflow generating portion, the storage portion having a partition wall extending in a direction intersecting the tube axis direction, and the partition wall having an opening for connecting the storage space with the surrounding space. In this structure, the storage space is provided at a position opposite to the surrounding space in the above-mentioned tube axis direction across the partition wall. Furthermore, the airflow generating portion is not arranged in the surrounding space between the X-ray tube storage portion and the surrounding portion (X-ray shielding portion), but is arranged in the storage space in a different chamber from the surrounding space. Thus, it is possible to suppress the adverse effects (misoperation, degradation, etc.) of the leaked X-rays on the airflow generating portion.

[0018] The partition wall may be provided with a first opening and a second opening, wherein the first opening is used to introduce gas at a position facing the airflow generating portion from the storage space into the surrounding space, and the second opening is used to discharge gas in the surrounding space after circulating around the X-ray tube storage portion from the surrounding space to the storage space, and the storage portion has an exhaust portion, which is provided at a position facing the second opening and is used to discharge gas to the outside. According to this structure, the gas circulating through the airflow generating portion can be efficiently circulated in the storage space and the surrounding space. In addition, by discharging the gas circulating around the X-ray tube storage portion from the storage space that is different from the surrounding space that stores the X-ray tube, it is possible to suppress the gas from being exhausted to the X-ray irradiation area, thereby suppressing the influence of the exhaust of the gas on the X-ray irradiation.

[0019] The X-ray tube storage unit and the partition wall may also be thermally connected. According to this structure, the heat of the X-ray tube storage unit can be transferred to the partition wall. As a result, the heat of the X-ray tube storage unit can be efficiently dissipated by using the gas flowing through the surface or opening of the partition wall.

[0020] The X-ray generator may further include a power supply unit disposed in the storage space for supplying electric power to the X-ray tube. According to this configuration, the power supply unit is also cooled by the gas flowing through the airflow generating unit in the storage space.

[0021] The X-ray generator may further include a control circuit for controlling the operation of the X-ray generator, which is arranged in the storage space, and the control circuit is arranged in a manner opposite to the X-ray tube storage portion across the power supply portion. In this structure, the control circuit is arranged on the opposite side of the X-ray tube storage portion across the power supply portion. In this way, by arranging the control circuit away from the X-ray tube, it is possible to suppress the adverse effects of leaked X-rays or heat from the X-ray tube on the control circuit, and to achieve stable operation of the X-ray generator.

[0022] The X-ray generating device may further include a control circuit for controlling the operation of the X-ray generating device disposed in the storage space, and an X-ray shielding component made of an X-ray shielding material is disposed between the control circuit and the X-ray tube. According to this structure, since the X-rays leaking from the X-ray tube toward the control circuit are shielded by the X-ray shielding component, the adverse effects of the leaking X-rays on the control circuit can be suppressed.

[0023] The inner surface of the surrounding portion may also have an inclined surface that is inclined along the tube axis direction in a manner that approaches the tube axis of the X-ray tube as it moves away from the partition wall. According to this structure, the gas that flows into the surrounding space from the opening of the partition wall along the above-mentioned tube axis direction is smoothly directed toward the inside of the surrounding space along the inclined surface of the surrounding portion (when an X-ray shielding portion is provided on the inner surface of the surrounding portion, it is the inner surface of the X-ray shielding portion provided on the inclined surface). As a result, the reduction in the inflow speed of the airflow can be suppressed, and the X-ray tube storage portion can be cooled more effectively.

[0024] The outer surface of the X-ray tube storage portion may also have an inclined surface that is opposite to the inclined surface of the surrounding portion and is inclined along the tube axis direction in a manner that approaches the tube axis of the X-ray tube as it moves away from the partition wall. By providing the inclined surface in the X-ray tube storage portion, the area of ​​the contact region of the X-ray tube storage portion with the insulating liquid (that is, the portion where the inner surface of the X-ray tube storage portion contacts the insulating liquid) is larger than that in the case where the inclined surface is not provided. Thus, the heat dissipation efficiency of the X-ray tube storage portion can be improved. In addition, by providing the inclined surface in the X-ray tube storage portion in a manner that is opposite to the inclined surface of the surrounding portion, the shape of the inner surface of the surrounding portion can follow the shape of the outer surface of the X-ray tube storage portion. Thus, compared with the case where the shape of the inner surface of the surrounding portion does not follow the shape of the outer surface of the X-ray tube storage portion, the gas flow in the surrounding space can be smoothed. As a result, the heat dissipation efficiency of the X-ray tube storage portion can be effectively improved.

[0025] Effects of the Invention

[0026] According to one embodiment of the present invention, an X-ray generating device capable of effectively achieving both cooling of an X-ray tube and shielding of leaked X-rays can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a perspective view showing the appearance of an X-ray generator according to one embodiment.

[0028] Figure 2 is along Figure 1 Cross-sectional view along line II-II.

[0029] Figure 3 is along Figure 2 A cross-sectional view of the upper wall portion taken along line III-III.

[0030] Figure 4 It is a cross-sectional view showing the structure of an X-ray tube.

[0031] Figure 5 It is a cross-sectional view of the X-ray generating device of the first variation.

[0032] Figure 6 It is a cross-sectional view of the X-ray generating device of the second variation. DETAILED DESCRIPTION

[0033] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same symbols are attached to the same or equivalent parts in each figure, and repeated description is omitted. In addition, the words representing specific directions such as "upper" and "lower" are based on the states shown in the accompanying drawings for convenience.

[0034] Figure 1 It is a perspective view showing the appearance of an X-ray generator according to one embodiment of the present invention. Figure 2 is along Figure 1 Cross-sectional view of line II-II. Figure 1 and Figure 2 The X-ray generating device 1 shown is, for example, a microfocus X-ray source used for X-ray non-destructive inspection for observing the internal structure of a subject. The X-ray generating device 1 has a housing 2. The housing 2 mainly contains: an X-ray tube 3 for generating X-rays; an X-ray tube storage portion 4 for storing a portion of the X-ray tube 3; and a power supply portion 5 for supplying electric power to the X-ray tube 3. The housing 2 has a first storage portion 21 and a second storage portion 22 (enclosing portion).

[0035] The first storage section 21 is a portion that mainly stores the power supply section 5. The first storage section 21 has a bottom wall section 211, an upper wall section 212, and a side wall section 213. The bottom wall section 211 and the upper wall section 212 each have a substantially square shape. The edge of the bottom wall section 211 and the edge of the upper wall section 212 are connected via four side wall sections 213. Thus, the first storage section 21 forms a substantially rectangular parallelepiped shape. In addition, in the present embodiment, for convenience, the direction in which the bottom wall section 211 and the upper wall section 212 are relative to each other is set as the Z direction, the bottom wall section 211 side is defined as the bottom, and the upper wall section 212 side is defined as the top. In addition, the directions in which the side wall sections 213 that are orthogonal to the Z direction and relative to each other are set as the X direction and the Y direction.

[0036] Figure 3 is from Figure 2 A cross-sectional view of the upper wall portion 212 when viewed from the lower side. Figure 3 As shown, a circular through hole, i.e., an opening 212a, is provided at the center of the upper wall 212 when viewed from the Z direction. In addition, a pair of openings 212b and 212c (a first opening and a second opening) are provided at the upper wall 212 at positions opposite to each other in the X direction across the opening 212a. The openings 212b and 212c have substantially rectangular through holes with their long sides along the Y direction and their corners chamfered in an arc shape.

[0037] An intermediate wall 214 is provided between the bottom wall 211 and the upper wall 212 at a position spaced apart from either the bottom wall 211 or the upper wall 212. By means of the intermediate wall 214, a first storage space S1 surrounded by the upper wall 212, the side wall 213 and the intermediate wall 214 and a second storage space S2 surrounded by the bottom wall 211, the side wall 213 and the intermediate wall 214 are defined inside the first storage section 21. In the first storage space S1, a power supply unit 5 is fixed to an upper surface 214a of the intermediate wall 214. In the second storage space S2, a control circuit board 7 is mounted on a lower surface 214b of the intermediate wall 214 in a state where a plate-shaped X-ray shielding member 6 made of an X-ray shielding material is interposed therebetween. In this embodiment, the X-ray shielding member 6 is fixed to the lower surface 214b of the intermediate wall 214, and the control circuit board 7 is fixed to the lower surface of the X-ray shielding member 6. As the material of the X-ray shielding component 6, for example, lead or a material having high X-ray shielding performance (lead, tungsten, barium sulfate, bismuth, etc.) mixed in a resin base material is listed. In the present embodiment, the X-ray shielding component 6 is a plate-shaped component containing lead. On the control circuit board 7, a control circuit for controlling the operation of each part of the X-ray generating device 1 (for example, the power supply unit 5, the air supply fan 9 described later, and the electron gun 11 described later) is formed through various electronic parts not shown in the figure. By configuring the X-ray shielding component 6 between the control circuit board 7 and the X-ray tube 3, the X-rays leaking from the X-ray tube 3 to the control circuit are shielded by the X-ray shielding component 6. Thus, the adverse effects of the leaked X-rays on the control circuit are suppressed. In addition, the X-ray shielding component 6 can also be arranged between the power supply unit 5 and the intermediate wall portion 214. With this structure, the X-ray shielding component 6 can also be used to shield the X-rays leaking from the X-ray tube 3 to the control circuit.

[0038] The second storage part 22 is connected to the upper part of the first storage part 21, and is a part for storing the X-ray tube 3 and the X-ray tube storage part 4. The second storage part 22 is composed of a wall part including a plate-shaped metal member of substantially uniform thickness. The shape of the inner surface of the second storage part 22 substantially corresponds to the shape of the outer surface of the second storage part 22. Examples of the material of the plate-shaped metal member include aluminum, iron, and alloys thereof. In the present embodiment, the material of the plate-shaped metal member constituting the second storage part 22 is iron. When the second storage part 22 is viewed from the direction along the tube axis AX of the X-ray tube 3 (tube axis direction, X-ray emission direction, Z direction), it surrounds the X-ray tube 3 and the X-ray tube storage part 4. The second storage part 22 has a cover part 221, a cylindrical part 222, a tapered part 223, and a flange part 224 in order from its upper end side. The cylindrical part 222 is a part formed in a cylindrical shape including a wall surface extending in the Z direction. The conical portion 223 is an end portion of the cylindrical portion 222 connected to the upper wall portion 212 side, and includes a portion of a wall surface that continuously and gently expands in diameter as it moves away from the cylindrical portion 222 along the Z direction. The cylindrical portion 222 and the conical portion 223 are spaced apart from the X-ray tube 3 and the X-ray tube storage portion 4 when viewed from the Z direction, and surround the X-ray tube 3 and the X-ray tube storage portion 4. In addition, the cylindrical portion 222 and the conical portion 223 are connected to each other in a cross-section of the ZX plane and the ZY plane in such a manner that the angle between the planar walls of the cylindrical portion 222 and the conical portion 223 is an obtuse angle. The flange portion 224 is an end portion of the conical portion 223 connected to the opposite side of the cylindrical portion 222, and includes a portion of a wall surface that extends outward when viewed from the Z direction. The flange portion 224 is fixed to the upper surface 212e of the upper wall portion 212 by screw fastening or the like. When viewed from the Z direction, the outer edge of the flange portion 224 is located outside the openings 212a, 212b, and 212c of the upper wall portion 212. The cover portion 221 is connected to the upper end of the cylindrical portion 222 so as to cover the upper opening of the cylindrical portion 222. A cover portion 221 is provided on the upper portion of the cover portion 221 for allowing at least the X-ray emission window 33a (see FIG. Figure 1 and Figure 4 ) is exposed to the outside. In addition, the cover 221 has an electron gun storage portion 221b formed in a manner that can store the electron gun 11 of the X-ray tube 3 and wiring (not shown) connected to the electron gun 11.

[0039] An X-ray shielding part 8 is provided on the entire inner surface of the inner space constituting the second storage part 22 (i.e., the inner surface 221c of the cover part 221, the inner surface 222a of the cylindrical part 222, and the inner surface 223a of the tapered part 223). The X-ray shielding part 8 includes an X-ray shielding material having an X-ray shielding performance higher than that of either the X-ray tube storage part 4 or the second storage part 22. The X-ray shielding part 8 is provided in a layered form covering the inner surface of the second storage part 22. The X-ray shielding part 8 is formed by, for example, bonding a plate-like member of a specific thickness made of an X-ray shielding material in a close manner in accordance with the inner surface shape of the second storage part 22 by an adhesive, a double-sided tape, etc. As the material of the X-ray shielding part 8, the same material as the above-mentioned X-ray shielding member 6 can be used. The X-ray shielding part 8 plays a role in shielding the leaked X-rays that pass through the second storage part 22 to the outside at the portion other than the opening 221a. The so-called leakage X-rays are the X-ray tube 3 with the target material T (refer to Figure 4 ) as a base point, and are taken out to the outside of the X-ray generating device 1 through an unexpected emission path different from the intended (regular) emission path. Here, the so-called intended emission path is a path through the X-ray emission window 33a and the opening 221a. For example, among the X-rays radially generated by the X-ray tube 3 with the target material T as a base point, the X-rays emitted in a direction intersecting the wall surface of the second storage section 22 (that is, outside the opening 221a) may become leakage X-rays. Specifically, among such X-rays, the X-rays that are not absorbed by the vacuum shell 10 of the X-ray tube 3 or the wall surface of the X-ray tube storage section 4, the second storage section 22, etc. that are present in the direction of X-ray travel and are transmitted and taken out to the outside of the X-ray generating device 1 become leakage X-rays. Furthermore, when leaked X-rays that may cause adverse effects occur, the X-ray shielding portion 8 may be provided on the emission path thereof, and does not necessarily need to be provided on the entire inner surface of the second housing portion 22 .

[0040] The X-ray tube storage part 4 is formed of a metal having a higher thermal conductivity (higher heat dissipation) than the second storage part 22 and the X-ray shielding part 8. Examples of the material of the X-ray tube storage part 4 include aluminum, iron, copper, and alloys containing these. In the present embodiment, the material of the X-ray tube storage part 4 is aluminum (or its alloy). The X-ray tube storage part 4 is a cylindrical shape having openings at both ends in the tube axis direction (Z direction) of the X-ray tube 3. The tube axis of the X-ray tube storage part 4 coincides with the tube axis AX of the X-ray tube 3. The X-ray tube storage part 4 includes a holding part 41, a cylindrical part 42, a tapered part 43, and a flange part 44. The holding part 41 is a part that holds the X-ray tube 3 in the flange part 311 using a fixing member not shown in the figure, and hermetically seals the upper opening of the X-ray tube storage part 4 together with the X-ray tube 3. The cylindrical part 42 is a part connected to the lower end of the holding part 41 and formed into a cylindrical shape including a wall surface extending in the Z direction. The conical portion 43 is connected to the end of the cylindrical portion 42, and includes a portion of a wall surface that expands continuously and gently as it moves away from the cylindrical portion 42 along the Z direction from the end. The cylindrical portion 42 and the conical portion 43 are connected to each other in a manner such that the angle between the planar walls of the cylindrical portion 42 and the conical portion 43 is an obtuse angle in the cross-section of the ZX plane and the ZY plane. The flange portion 44 is connected to the end of the conical portion 43 and extends outward when viewed from the Z direction. The flange portion 44 is configured as an annular component with a thicker wall than the cylindrical portion 42 and the conical portion 43. As a result, the heat capacity is increased and the heat dissipation is improved. The flange portion 44 surrounds the opening 212a of the upper wall portion 212 when viewed from the Z direction and is airtightly fixed to the upper surface 212e of the upper wall portion 212 at a position further inside than the openings 212b and 212c. In this embodiment, the flange portion 44 is thermally connected (heat-conductively in contact with) the upper surface 212 e of the upper wall portion 212. The interior of the X-ray tube housing portion 4 is airtightly sealed (filled with) insulating oil 45 which is an electrically insulating liquid.

[0041] The power supply unit 5 is a part that supplies electric power of several kV to several hundred kV to the X-ray tube 3. The power supply unit 5 has an electrically insulating insulating block 51 containing solid epoxy resin, and an internal circuit board 52 containing a high voltage generating circuit molded in the insulating block 51. The insulating block 51 is roughly rectangular. The central portion of the upper surface of the insulating block 51 passes through the opening 212a of the upper wall 212 and protrudes. On the other hand, the upper surface edge 51a of the insulating block 51 is airtightly fixed to the lower surface 212f of the upper wall 212. In the center of the upper surface of the insulating block 51, a high-voltage feeder 54 including a cylindrical socket electrically connected to the internal circuit board 52 is arranged. The power supply unit 5 is electrically connected to the X-ray tube 3 via the high-voltage feeder 54.

[0042] The outer diameter of the portion of the insulating block 51 inserted into the opening 212 a (ie, the center portion of the upper surface) is the same as or slightly smaller than the inner diameter of the opening 212 a .

[0043] In this embodiment, the side walls 213A and 213B facing each other in the X direction are respectively provided with ventilation holes A. The ventilation holes A are provided with a plurality of ventilation holes 213a for communicating the first storage space S1 with the outside. An air supply fan 9 (airflow generating unit) is provided inside the side wall 213A. The air supply fan 9 effectively cools each part such as the X-ray tube storage part 4, the power supply part 5, and the control circuit board 7 by utilizing the space structure formed in the housing 2.

[0044] Specifically, the air supply fan 9 generates cooling gas by taking in outside air from the ventilation hole A provided in the side wall 213A, and supplies the cooling gas to the space S11 between the side wall 213A and the power supply unit 5 in the first storage space S1. The power supply unit 5 is cooled by the cooling gas supplied to the space S11.

[0045] A part of the cooling gas flowing in the space S11 flows into the surrounding space S3 defined between the outer surface of the X-ray tube housing 4 (the outer surface of the cylindrical portion 42 and the outer surface 43a of the tapered portion 43) and the inner surface of the second housing 22 (the inner surface 8a of the X-ray shielding portion 8 relative to the portion where the X-ray shielding portion 8 is provided) through the opening 212b of the upper wall portion 212. The surrounding space S3 is also defined between the X-ray tube 3 and the inner surface of the second housing 22 (the inner surface 8a of the X-ray shielding portion 8 relative to the portion where the X-ray shielding portion 8 is provided). The surrounding space S3 is formed to surround the X-ray tube 3 and the X-ray tube housing 4 when viewed from the Z direction. The cooling gas flowing into the surrounding space S3 passes around the X-ray tube 3 and the X-ray tube housing 4 to cool the outer surfaces of the X-ray tube 3 and the X-ray tube housing 4. Furthermore, the cooling gas flows into the first storage space S1 (space S12 between the side wall portion 213B and the power supply portion 5 in the first storage space S1) again through the opening portion 212c of the upper wall portion 212, and is discharged to the outside from the ventilation hole portion A (exhaust portion) formed in the side wall portion 213B.

[0046] The middle wall portion 214 is provided with an opening 214c that connects the space S11 with the second storage space S2, and an opening 214d that connects the space S12 with the second storage space S2. Thus, a portion of the cooling gas flowing in the space S11 flows into the second storage space S2 through the opening 214c of the middle wall portion 214. The control circuit board 7 is cooled by the cooling gas flowing into the second storage space S2. Furthermore, the cooling gas flows into the first storage space S1 (space S12) again through the opening 214d of the middle wall portion 214, and is discharged to the outside from the ventilation hole portion A formed in the side wall portion 213B.

[0047] Next, the structure of the X-ray tube 3 will be described. Figure 4As shown, the X-ray tube 3 is a so-called reflection type X-ray tube. The X-ray tube 3 includes a vacuum shell 10 as a vacuum enclosure that keeps the interior vacuum, an electron gun 11 as an electron generating unit, and a target material T. The electron gun 11 has, for example, a cathode C formed by impregnating a substrate containing a high melting point metal material or the like with a substance that is easy to radiate electrons. In addition, the target material T is a plate-shaped component containing a high melting point metal material such as tungsten. The center of the target material T is located on the tube axis AX of the X-ray tube 3. The electron gun 11 and the target material T are housed inside the vacuum shell 10. If the electrons emitted from the electron gun 11 are incident on the target material T, X-rays are generated. X-rays are generated radially with the target material T as a base point. Among the X-ray components toward the X-ray exit window 33a side, the X-rays taken out to the outside through the X-ray exit window 33a are used as the desired X-rays.

[0048] The vacuum housing 10 is mainly composed of an insulating valve 12 formed of an insulating material (such as glass) and a metal part 13 having an X-ray emission window 33a. The metal part 13 has a main body 31 that accommodates a target T serving as an anode and an electron gun housing 32 that accommodates the electron gun 11 serving as a cathode.

[0049] The main body 31 is formed in a cylindrical shape and has an internal space S. A cover plate 33 having an X-ray exit window 33a is fixed to one end (outer end) of the main body 31. The material of the X-ray exit window 33a is an X-ray transparent material, such as beryllium or aluminum. One end side of the internal space S is closed by the cover plate 33. The main body 31 has a flange portion 311 and a cylindrical portion 312. The flange portion 311 is provided on the outer periphery of the main body 31. The flange portion 311 is a portion fixed to the retaining portion 41 of the above-mentioned X-ray tube storage portion 4. The cylindrical portion 312 is a portion formed in a cylindrical shape on one end side of the main body 31.

[0050] The electron gun housing 32 is formed in a cylindrical shape and is fixed to the side portion of one end side of the main body 31. The central axis of the main body 31 (i.e., the tube axis AX of the X-ray tube 3) is substantially orthogonal to the central axis of the electron gun housing 32. The interior of the electron gun housing 32 is connected to the internal space S of the main body 31 via an opening 32a provided at the end of the electron gun housing 32 on the main body 31 side.

[0051] The electron gun 11 includes a cathode C, a heater 111, a first grid electrode 112, and a second grid electrode 113. The diameter of the generated electron beam can be reduced (micro-focused) by the cooperation of each component. The cathode C, the heater 111, the first grid electrode 112, and the second grid electrode 113 are respectively mounted on a stem substrate 115 via a plurality of feed pins 114 extending in parallel. The cathode C, the heater 111, the first grid electrode 112, and the second grid electrode 113 are fed from the outside via the corresponding feed pins 114.

[0052] The insulating valve 12 is formed in a substantially cylindrical shape. One end side of the insulating valve 12 is connected to the main body 31. The insulating valve 12 holds a target support 60 that fixes the target T at the front end at its other end side. The target support 60 is formed in a cylindrical shape by, for example, copper material, and extends in the Z direction. An inclined surface 60a is formed on the front end side of the target support 60, which is inclined in a manner away from the electron gun 11 as it goes from the insulating valve 12 side to the main body 31 side. The target T is buried in the end of the target support 60 in a manner that is flush with the inclined surface 60a.

[0053] The base end portion 60b of the target support portion 60 protrudes outward from the lower end portion of the insulating valve 12 and is connected to the high voltage feeder 54 of the power supply unit 5 (see Figure 2 In the present embodiment, the vacuum housing 10 (metal portion 13) is set to a ground potential, and a positive high voltage is supplied to the target support portion 60 in the high voltage feeder 54. However, the voltage application method is not limited to the above example.

[0054] [Effects]

[0055] Next, the effects of one mode of the present embodiment are described. As described above, the X-ray generating device 1 includes: an X-ray tube 3 that generates X-rays; an X-ray tube housing 4 that houses at least a portion of the X-ray tube 3 (in the present embodiment, a portion located below the flange portion 311, at least a portion including the insulating valve 12) and is sealed with insulating oil 45; a second housing 22 that surrounds the X-ray tube housing 4 when viewed from the tube axis direction of the X-ray tube 3 (a direction along the tube axis AX, which is the same as the Z direction in the present embodiment); an air supply fan 9 that circulates cooling gas in an enclosed space S3 defined between the X-ray tube housing 4 and the enclosing portion 22; and an X-ray shielding portion 8 that is provided on the inner surface or outer surface of the enclosing portion 22 and is made of a material having a higher X-ray shielding performance than the X-ray tube housing 4 and the enclosing portion 22.

[0056] Here, materials generally showing good properties as X-ray shielding materials often have low thermal conductivity. Specifically, lead, which is an X-ray shielding material exemplified in this embodiment, has lower thermal conductivity than aluminum, which is exemplified as a metal material forming the X-ray tube housing 4. Therefore, if the X-ray tube housing 4 is formed of an X-ray shielding material, there is a problem that the heat dissipation of the X-ray tube housing 4 is deteriorated, and the cooling efficiency of the X-ray tube housing 4 caused by the cooling gas flowing in the surrounding space S3, that is, the cooling efficiency of the X-ray tube 3, is reduced. On the other hand, when the second housing 22 is formed of an X-ray shielding material, it becomes difficult to have both the role of shielding leaked X-rays and the role of a shell for the X-ray tube housing 4. In particular, if the second housing 22 that can stand on its own is formed only by a material having X-ray shielding performance (such as lead), there is a possibility that the material must be more than the necessary amount for obtaining the required X-ray shielding performance in order to ensure the strength of the second housing 22. In addition, there is a problem that the second housing 22 becomes heavy. Furthermore, in order to satisfy various requirements such as the X-ray shielding performance and independence as described above, as well as processability and manufacturing cost, there is also a problem that the material selection options for the second housing portion 22 are limited.

[0057] In contrast, according to the X-ray generator 1, the heat generated by the X-ray tube 3 is absorbed by the insulating oil 45 sealed in the X-ray tube housing 4. Specifically, when the electrons emitted from the electron gun 11 collide with the target T, the heat generated in the target T is transferred from the front end side of the target support 60 to the base end 60b side. Then, the portion of the target support 60 exposed to the outside of the vacuum housing 10 (the portion immersed in the insulating oil 45) is radiated to the insulating oil 45. In addition, the heat absorbed by the insulating oil 45 is transferred to the X-ray tube housing 4, and the X-ray tube housing 4 is cooled by the cooling gas flowing through the surrounding space S3 formed between the X-ray tube housing 4 and the second housing 22, so that the X-ray tube 3 can be effectively cooled. In addition, since a part of the X-ray tube 3 protruding from the X-ray tube housing 4 is also accommodated in the surrounding space S3, the X-ray tube 3 itself can also be cooled by the cooling gas.

[0058] Furthermore, by providing the X-ray shielding portion 8 as a component different from the second housing portion 22 on the inner surface of the second housing portion 22, it is possible to appropriately shield the X-rays leaking around the X-ray generator 1 (mainly the leaked X-rays other than the components of the X-rays generated radially with the target material T as the base point, which are caused by the X-rays in the direction of the X-ray exit window 33a). Thus, according to the X-ray generator 1, it is possible to effectively take into account both the cooling of the X-ray tube 3 and the shielding of the leaked X-rays. Taking into account both the cooling of the X-ray tube 3 and the shielding of the leaked X-rays is particularly important when it is necessary to micro-focus or increase the output of the X-rays, and the above-mentioned effect becomes significant.

[0059] The X-ray tube housing 4 is made of a metal material (aluminum in this embodiment) having a higher thermal conductivity than the second housing 22 and the X-ray shield 8. Thus, the heat generated by the X-ray tube 3 can be effectively dissipated by the cooling gas flowing through the surrounding space S3.

[0060] In addition, the X-ray shielding portion 8 is provided on the inner surface of the second storage portion 22 (in the present embodiment, a portion of the inner surface 221c of the cover portion 221, the inner surface 222a of the cylindrical portion 222, and the inner surface 223a of the tapered portion 223). Thus, compared with the case where the X-ray shielding portion 8 is provided on the outer surface of the second storage portion 22, it is possible to prevent the X-ray shielding portion 8 from peeling off due to contact from the outside, etc. In addition, the amount of material required for forming the X-ray shielding portion 8 can be reduced. In addition, since there is no difference in the X-ray shielding energy itself, the X-ray shielding portion 8 can also be provided on the outer surface of the second storage portion 22.

[0061] In addition, the X-ray generating device 1 includes a first storage section 21 that defines a storage space (a space including the first storage space S1 and the second storage space S2) for storing the air supply fan 9. The first storage section 21 has an upper wall section 212 as a partition wall extending in a direction intersecting the tube axis direction (Z direction) of the X-ray tube 3. The upper wall section 212 is provided with openings 212b and 212c that connect the first storage space S1 and the surrounding space S3. In this structure, the first storage space S1 is provided at a position opposite to the surrounding space S3 in the above-mentioned tube axis direction across the upper wall section 212. In addition, the air supply fan 9 is not arranged in the surrounding space S3 between the X-ray tube storage section 4 and the second storage section 22 (X-ray shielding section 8), but is arranged in the first storage space S1 in a different room from the surrounding space S3. As a result, it is possible to suppress the adverse effects (misoperation, deterioration, etc.) of the air supply fan 9 caused by the leakage X-rays.

[0062] In addition, the upper wall portion 212 is provided with: an opening portion 212b for introducing cooling gas from the space S11 into the surrounding space S3 at a position facing the air supply fan 9; and an opening portion 212c for discharging the cooling gas that has circulated around the X-ray tube storage portion 4 in the surrounding space S3 from the surrounding space S3 to the space S12. The first storage portion 21 has an exhaust portion (ventilation hole portion A of the side wall portion 213B) provided at a position facing the opening portion 212c for discharging the cooling gas to the outside. According to this structure, the cooling gas circulated by the air supply fan 9 can be efficiently circulated in the first storage space S1 and the surrounding space S3. In addition, by discharging the cooling gas that circulates around the X-ray tube storage portion 4 from the first storage space S1 that is different from the surrounding space S3 that stores the X-ray tube 3, it is possible to suppress the cooling gas from being exhausted to the X-ray irradiation area. As a result, it is possible to suppress the exhaust of the cooling gas from affecting X-ray irradiation from the X-ray emission window 33 a of the X-ray tube 3 or imaging of an X-ray irradiation target.

[0063] In addition, the X-ray tube storage part 4 is thermally connected to the upper wall part 212. As described above, in this embodiment, the flange part 44 of the X-ray tube storage part 4 and the upper surface 212e of the upper wall part 212 are in thermally conductive contact. As a result, the heat of the X-ray tube storage part 4 can be transferred to the upper wall part 212. As a result, the heat of the X-ray tube storage part 4 can be efficiently dissipated by the cooling gas flowing on the surface of the upper wall part 212 or the openings 212b and 212c.

[0064] In addition, the X-ray generating device 1 includes a power supply unit 5 which is arranged in the first storage space S1 (storage space) and supplies electric power to the X-ray tube 3. According to this structure, the power supply unit 5 can also be cooled by the cooling gas blown by the air supply fan 9 in the first storage space S1. In addition, a gap may or may not be provided between the side surface of the power supply unit 5 opposite to the Y direction and the side wall portion 213 of the first storage portion 21. When a gap is provided, the power supply unit 5 can be cooled more effectively by using the cooling gas passing through the gap (that is, the cooling gas flowing from the space S11 to the space S12 via the gap).

[0065] In addition, the X-ray generating device 1 includes a control circuit board 7 which is arranged in the second storage space S2 (storage space) and controls the operation of the X-ray generating device 1. The control circuit board 7 is arranged in a manner opposite to the X-ray tube storage portion 4 across the power supply unit 5. In this structure, the control circuit board 7 is arranged on the opposite side of the X-ray tube storage portion 4 across the power supply unit 5. Specifically, in the present embodiment, the interior of the housing 2 has a three-level structure in which an enclosed space S3, a first storage space S1, and a second storage space S2 are sequentially formed. Furthermore, the control circuit board 7 is arranged in the second storage space S2 which is located at a relative position to the enclosed space S3 across the first storage space S1 where the power supply unit 5 is arranged. In this way, by arranging the control circuit board 7 away from the X-ray tube 3, it is possible to suppress the adverse effects of leaked X-rays or heat from the X-ray tube 3 on the control circuit mounted on the control circuit board 7, and to achieve stable operation of the X-ray generating device 1.

[0066] In addition, an X-ray shielding member 6 made of an X-ray shielding material is disposed between the control circuit board 7 and the X-ray tube 3. Thus, since the X-rays leaking from the X-ray tube 3 toward the control circuit board 7 are shielded by the X-ray shielding member 6, the adverse effects of the leaked X-rays on the control circuit can be suppressed.

[0067] In addition, the inner surface of the second storage section 22 has an inclined surface that is inclined in a manner that approaches the tube axis AX of the X-ray tube 3 as it moves away from the upper wall section 212 along the tube axis direction (Z direction). In the present embodiment, the inner surface 223a of the tapered portion 223 corresponds to the inclined surface. According to this structure, the cooling gas that flows into the surrounding space S3 from the opening 212b of the upper wall section 212 along the tube axis direction can be smoothly directed toward the inner side of the surrounding space S3 (toward the tube axis AX of the X-ray tube 3 and toward the cylindrical portion 42 and the tapered portion 43 of the X-ray tube storage section 4) along the inner surface 8a of the X-ray shielding section 8 provided on the above-mentioned inclined surface. As a result, it is possible to suppress the reduction in the inflow speed of the cooling gas and cool the X-ray tube storage section 4 more effectively. In addition, when the X-ray shielding portion 8 is provided on the outer surface of the second housing portion 22 , the cooling gas flowing into the surrounding space S3 from the opening portion 212 b of the upper wall portion 212 along the tube axis direction is allowed to flow along the inner surface 223 a of the tapered portion 223 , thereby obtaining the same effect as described above.

[0068] In addition, the outer surface of the X-ray tube storage part 4 has an inclined surface that is opposite to the inclined surface of the second storage part 22 (the inner surface 223a of the tapered part 223) and is inclined in a manner that approaches the tube axis AX of the X-ray tube 3 as it moves away from the upper wall part 212 along the tube axis direction (Z direction). In this embodiment, the outer surface 43a of the tapered part 43 corresponds to the inclined surface provided on the outer surface of the X-ray tube storage part 4. By providing the above-mentioned inclined surface (outer surface 43a) on the X-ray tube storage part 4, the area of ​​the contact region between the X-ray tube storage part 4 and the insulating oil 45 (that is, the portion where the inner surface of the X-ray tube storage part 4 contacts the insulating oil 45) is larger than the case where the inclined surface is not provided. That is, in the X-ray tube storage part 4, the area of ​​the region that directly absorbs heat from the insulating oil 45 and dissipates heat in the surrounding space S3 becomes larger. As a result, the heat dissipation efficiency of the heat of the X-ray tube storage part 4 can be improved. In particular, since the heat from the X-ray tube 3 is dissipated from the portion of the target support 60 exposed to the outside of the vacuum housing 10 (the portion immersed in the insulating oil 45) to the insulating oil 45, the heat dissipation efficiency from the X-ray tube 3 can be further improved by providing the inclined surface in the region opposite to the portion. In addition, by providing the inclined surface (outer surface 43a) in the X-ray tube housing 4 so as to be opposite to the inclined surface (inner surface 223a) of the second housing 22, as shown in FIG. Figure 2 As shown, the shape of the inner surface of the second housing portion 22 can be made to follow the shape of the outer surface of the X-ray tube housing portion 4. As a result, the cooling gas in the surrounding space S3 can be made to flow smoothly, compared with the case where the inner surface shape of the second housing portion 22 does not follow the shape of the outer surface of the X-ray tube housing portion 4. In addition, since the flow path width of the surrounding space S3 formed between the second housing portion 22 and the X-ray tube housing portion 4 can be reduced, the flow rate of the cooling gas can also be increased. As a result, the heat dissipation efficiency of the X-ray tube housing portion 4 can be effectively improved.

[0069] [First Modification]

[0070] Reference Figure 5 , the X-ray generator 1A of the first variation is described. The main difference between the X-ray generator 1A and the X-ray generator 1 is that the X-ray shielding component 6 and the control circuit board 7 are arranged in the first storage space S1 ( Figure 5 In the example, it is the position of the air supply fan 9 facing the space S11). Figure 5In the example, the X-ray shielding member 6 is fixed to the side of the insulating block 51 facing the space S11. In addition, the control circuit board 7 is fixed to the X-ray shielding member 6 at a position on the opposite side of the insulating block 51 across the X-ray shielding member 6. Even with this structure, since the X-rays leaking from the X-ray tube 3 toward the control circuit are shielded by the X-ray shielding member 6, the adverse effects of the leaked X-rays on the control circuit can be suppressed. In addition, by arranging the control circuit board 7 at a position facing the air supply fan 9, the cooling efficiency of the control circuit board 7 can also be improved.

[0071] The difference between the X-ray generating device 1A and the X-ray generating device 1 is that the intermediate wall portion 214 is omitted and the second storage space S2 is not provided. Figure 5 In the example, the intermediate wall portion 214 is omitted, and the power supply unit 5 is directly arranged on the bottom wall portion 211. By accommodating the control circuit board 7 and wiring (not shown) in the first storage space S1, the intermediate wall portion 214 and the second storage space S2 can be omitted in this way, and the internal space of the housing 2 can be set as a two-level structure, which can realize the miniaturization of the X-ray generating device 1A.

[0072] [Second Modification]

[0073] Reference Figure 6 , the X-ray generating device 1B of the second variation is described. The main difference between the X-ray generating device 1B and the X-ray generating device 1 is that the ventilation hole portion A in the side wall portion 213A is provided at a position facing the second storage space S2, and the air supply fan 9 is provided in the second storage space S2 in a manner facing the ventilation hole portion A. In the X-ray generating device 1B, the ventilation hole portion A is not provided in the portion of the side wall portion 213A facing the space S11. In this case, a portion of the cooling gas supplied from the air supply fan 9 to the second storage space S2 flows into the space S11 through the opening portion 214c of the intermediate wall portion 214, and then flows into the surrounding space S3 through the opening portion 212b of the upper wall portion 212. In addition, a portion of the cooling gas supplied from the air supply fan 9 passes through the second storage space S2 and flows into the space S12 through the opening portion 214d of the intermediate wall portion 214. In this way, when the air supply fan 9 is arranged in the second storage space S2, the cooling gas can also pass through the entire space in the housing 2 (the first storage space S1, the second storage space S2 and the surrounding space S3), so the X-ray tube storage unit 4, the power supply unit 5 and the control circuit board 7 can be appropriately cooled. In addition, since the air supply fan 9 can be further away from the X-ray tube 3, the adverse effect of the X-rays leaked from the X-ray tube 3 on the air supply fan 9 can be further suppressed.

[0074] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and the present invention can be variously modified within the scope of the present invention. That is, the shape and material of each part of the X-ray generating device are not limited to the specific shapes and materials shown in the above embodiments.

[0075] Although the X-ray tube 3 is a reflection type X-ray tube that extracts X-rays from a direction different from the electron incident direction to the target, it may be a transmission type X-ray tube that extracts X-rays along the electron incident direction to the target (X-rays generated by the target are transmitted through the target itself and extracted from the X-ray exit window). In addition, in the above embodiment, although the structure using the air supply fan 9 as the airflow generating unit is exemplified, the airflow generating unit is not limited to the air supply fan 9 that supplies gas from the outside to the inside (inside the housing 2). For example, instead of the air supply fan 9, a suction fan that draws the internal gas to the outside and circulates the gas may be used as the airflow generating unit. In addition, the air supply fan 9 (circulation unit) may have a function of circulating not only cold air (cooling gas) but also warm air. For example, the air supply fan 9 may be configured to be switchable between a mode of supplying cold air and a mode of supplying warm air. After the X-ray generator 1 is started, in order to stabilize the operation of the X-ray tube 3, there may be a case where the temperature in the X-ray tube storage unit 4 (i.e., the temperature of the insulating oil 45) is to be raised to a certain temperature. In this case, the blower fan 9 can be switched to blow warm air, so that warm air can flow in the surrounding space S3, and the temperature in the X-ray tube storage unit 4 can be efficiently increased. As a result, the time from starting the X-ray tube generator 1 to stabilizing the operation of the X-ray tube 3 can be shortened.

[0076] The outer surface of the X-ray tube storage part 4 (in the above embodiment, the outer surface of the cylindrical part 42 and the outer surface 43a of the tapered part 43) may also have a portion formed in a concave-convex shape. Alternatively, one or more cooling fans extending convexly in the circumferential direction may be provided on the outer surface of the X-ray tube storage part 4. According to the above structure, the surface area of ​​the X-ray tube storage part 4 with respect to the surrounding space S3 can be increased, and the heat dissipation efficiency can be improved.

[0077] In the above-mentioned embodiment, although the cone 43 is provided in the X-ray tube storage section 4, it is not necessary to provide the cone 43. For example, the side shape of the X-ray tube storage section 4 may be a cylindrical shape without the cone 43. Similarly, it is not necessary to provide the cone 223 in the second storage section 22. For example, the side shape of the second storage section 22 may be a cylindrical shape without the cone 223. In addition, in this case, a wind straightening plate may be provided on the side of the second storage section 22 instead of the inclined surface of the second storage section 22. The wind straightening plate is, for example, a component that is provided in a circular ring shape along the inner surface 8a of the X-ray shielding section 8 when viewed from the Z direction, and has an inclined surface that is inclined in a manner that approaches the tube axis AX of the X-ray tube 3 as it moves away from the upper wall section 212 in the tube axis direction.

[0078] In the above-mentioned embodiment, the X-ray shielding part 8 is bonded to the inner surface of the second storage part 22 by an adhesive, a double-sided tape, etc., but the method of fixing the X-ray shielding part 8 to the second storage part 22 is not limited thereto. The X-ray shielding part 8 may also be fixed to the inner surface (or outer surface) of the second storage part 22 by screw fastening or a joint, etc. In addition, when fixed by a joint, the joint may also function as the above-mentioned wind-rectifying plate. That is, the joint used to fix the X-ray shielding part 8 to the second storage part 22 may also have the function of a wind-rectifying plate.

[0079] The number, shape, and size of the ventilation openings 212b and 212c provided in the upper wall 212 are not particularly limited. Similarly, the number, shape, and size of the ventilation openings 214c and 214d provided in the intermediate wall 214 are not particularly limited.

[0080] Explanation of symbols

[0081] 1, 1A, 1B…X-ray generating device, 3…X-ray tube, 4…X-ray tube storage portion, 5…power supply portion, 6…X-ray shielding component, 7…control circuit board, 8…X-ray shielding portion, 9…air supply fan (airflow generating portion), 21…first storage portion (storage portion), 22…second storage portion (enclosing portion), 45…insulating oil (insulating liquid), 212…upper wall portion (partition wall), 212b…opening portion (first opening portion), 212c…opening portion (second opening portion), AX…tube axis, S1…first storage space, S2…second storage space, S3…enclosing space.

Claims

1. An X-ray generating device, characterized in that: include: An X-ray tube that produces X-rays; A control circuit for controlling the operation of the X-ray generating device; an X-ray tube housing portion that houses at least a portion of the X-ray tube and is sealed with an insulating liquid; a surrounding portion, which surrounds the X-ray tube housing portion when viewed from the tube axis direction of the X-ray tube; an air flow generating section for causing gas to flow in an enclosed space defined between the X-ray tube housing section and the enclosing section; and an X-ray shielding portion, which is arranged inside or outside the surrounding portion and is made of a material having a higher X-ray shielding performance than the X-ray tube housing portion and the surrounding portion; An opening is provided to allow a storage space storing the airflow generating section to communicate with the surrounding space so that cooling gas generated by the airflow generating section flows into the surrounding space.

2. The X-ray generating device according to claim 1, characterized in that: The opening portion is provided at a position facing the airflow generating portion.

3. The X-ray generating device according to claim 1 or 2, characterized in that: The control circuit is disposed in the storage space at a position facing the airflow generating portion.

4. The X-ray generating device according to any one of claims 1 to 3, characterized in that: An X-ray shielding member made of an X-ray shielding material is arranged between the airflow generating unit and the X-ray tube.

5. The X-ray generating device according to any one of claims 1 to 4, characterized in that: The control circuit is arranged in the storage space. An X-ray shielding member made of an X-ray shielding material is arranged between the control circuit and the X-ray tube.

6. The X-ray generating device according to any one of claims 1 to 5, characterized in that: The invention further includes a storage portion that defines the storage space and has a partition wall provided with the opening.

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