JP2006073254A - Rotary anode x-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a X-ray tube device which can output X-ray of a prescribed strength stably for a long period of time. <P>SOLUTION: A rotary anode X-ray tube of the invention having a dynamic pressure type slide bearing 6 for which a liquid metal lubricant is used, has at a neck portion 4 of an outer ring type rotation axis 4 a through hole 7 through which a gas generated inside the dynamic pressure type slide bearing is exhausted. With this construction, outward extruding of the liquid metal lubricant by the gas generated inside the dynamic pressure type slide bearing 6 is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an X-ray tube device used as an X-ray source in an X-ray device for obtaining a transmission image of an object, and more particularly to a rotary anode type X-ray tube.

  For example, in the field of medical diagnostic apparatuses and nondestructive inspection apparatuses, X-rays are widely used for fluoroscopic imaging of inspection objects, that is, subjects.

  As shown in FIG. 3, in the rotary anode type X-ray tube 101, the disc-shaped rotary anode 103 on which the target layer 103a of the X-ray tube main body 102 is formed is connected to a cylindrical rotary body 104 via a support shaft 104a. Has been. The cylindrical rotating body 104 includes a columnar fixed body 105 and functions as a rotor when connected to the support shaft 104a. That is, the rotating body 104 constitutes a hydrodynamic slide bearing in cooperation with the fixed body 105.

  A predetermined gap is provided between the fixed body 105 and the rotating body 104, and liquid metal lubrication that is in a liquid state while the rotating body 104 is rotated, such as Ga, is provided in the spiral grooves 105a and 105b and the gap portion between them. -In-Sn alloy is supplied.

In addition, a rotary anode type X-ray tube using a dynamic pressure type slide bearing capable of outputting a predetermined dose of X-rays suitable for fluoroscopic imaging over a long period of time has already been put into practical use (for example, see Patent Document 1). .
JP2002-025483

  In the X-ray tube main body 102 of the rotary anode X-ray tube 101 shown in FIG. 3, the liquid metal lubricant has a thrust ring 105c positioned on one end of the fixed body 105, that is, on the side opposite to the side where the rotary anode 103 is provided. By doing so, it is sealed between the rotating body 105.

  However, in the liquid metal lubricant supplied to the gap portion between the rotating body 105 and the fixed body 104, the gas generated by the rotation of the rotating body 105 is away from the thrust ring 111, that is, “A”. There is a problem of leakage from the gap (bearing) portion by increasing the internal pressure in the vicinity of the portion and increasing the internal pressure.

  An object of the present invention is to provide an X-ray tube apparatus capable of outputting X-rays having a predetermined intensity stably over a long period of time.

According to the present invention, a rotating anode that emits X-rays when irradiated with an electron beam, an outer ring rotating type rotating body connected to the rotating anode, and a predetermined position inside the rotating body, A fixed shaft that rotatably supports the rotating body; and a liquid metal lubricant that is supplied to a gap between the rotating body and the fixed shaft, the rotating body, the fixed shaft, and the liquid metal lubricant. In a rotating anode type X-ray tube device that functions as a hydrodynamic slide bearing,
A rotating anode type X-ray tube device characterized in that a portion of the rotating body to which the rotating anode is connected is formed so that gas generated inside the hydrodynamic slide bearing can be discharged to the outside of the bearing. It is to provide.

  Further, the present invention is a fixed shaft having one end formed non-fixed, and is positioned outside the fixed shaft from the non-fixed end portion side of the fixed shaft, and on the non-fixed end portion side, An outer ring type rotating shaft holding an anode member that emits X-rays when irradiated with an electron beam, a liquid metal lubricant interposed between the fixed shaft and the outer ring type rotating shaft, and the outer ring type rotation Provided is a rotating anode type linear tube having an exhaust hole provided on the non-fixed end side of a shaft and capable of exhausting gas generated in the vicinity of the liquid metal lubricant. .

  In addition, the present invention has a fixed shaft and a cylindrical neck portion, and an anode member that emits X-rays when the neck portion is irradiated with an electron beam is fixed. An outer ring type rotary shaft positioned so as to be rotatable around the fixed shaft from one end side of the fixed shaft, a liquid metal lubricant interposed between the fixed shaft and the outer ring type rotary shaft, and the fixed A predetermined length with respect to the axial direction of the fixed shaft is given to the one end side of the shaft with a predetermined gap with respect to the inner diameter of the cylindrical portion of the neck portion of the outer ring rotating shaft. Thus, the present invention provides a rotary anode type X-ray tube having a projection that can exhaust gas generated in the vicinity of the liquid metal lubricant.

  According to the present invention, the durability of an outer ring rotating type rotary anode X-ray apparatus using a hydrodynamic slide bearing is improved, and X-rays having a predetermined intensity can be obtained stably over a long period of time. Therefore, it is possible to extend the life of medical diagnostic devices and non-destructive inspection devices that use a rotating anode X-ray tube.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, for example, a rotary anode X-ray tube apparatus 1 that is used as an X-ray source used to obtain an X-ray fluoroscopic image and emits X-rays having a predetermined wavelength and a predetermined intensity is a vacuum (not shown). The X-ray tube main body 2 is accommodated in the envelope. Although not described in detail, the vacuum envelope is filled with insulating oil that hermetically supports the X-ray tube main body 2.

  The X-ray tube main body 2 includes a disk-shaped rotary anode 3 provided with a target layer 3a that emits X-rays when irradiated with an electron beam from an electron source (not shown), and an outer ring type rotation that rotatably supports the rotary anode 3 A fixed shaft which is disposed at a predetermined interval between the shaft 4 and the inner wall of the outer ring type rotating shaft 4 inside the outer ring type rotating shaft 4 and constitutes a hydrodynamic slide bearing 6 in cooperation with the outer ring type rotating shaft 4. 5

  The outer ring type rotation shaft 4 is formed in a cylindrical shape by a conductor typified by copper, for example, and functions as a rotor that generates thrust (rotation force) for rotating the rotary anode 3. A stator coil (not shown) that provides a magnetic field for operating the outer ring type rotating shaft 4 as a rotor is provided at a predetermined position facing the outer periphery of the outer ring type rotating shaft 4.

  The fixed shaft 5 is formed with first and second spiral grooves 5a and 5b that are given a specific direction along the axial direction. Further, a lubricant holding portion 5 c to which a liquid metal lubricant, for example, a Ga—In—Sn alloy is supplied is formed at a predetermined position of the fixed shaft 5. The interval between the fixed shaft 5 and the inner wall of the outer ring type rotating shaft 4 is set to 20 μm, for example.

  Therefore, the first and second spiral grooves 5 a and 5 b, that is, the fixed shaft 5, the liquid metal lubricant, and the outer ring type rotating shaft 4 constitute a hydrodynamic slide bearing 6. The outer ring type rotating shaft 4 moves in the axial direction at one end portion of the fixed shaft 5, that is, a position opposite to the side where the rotating anode 3 is positioned when the outer ring type rotating shaft 4 is mounted. A thrust ring 5d is provided that prevents the liquid metal lubricant from leaking out while preventing it from coming off. In addition, the liquid metal lubricant is in a direction perpendicular to the axis of the fixed shaft 5, in a portion facing the thrust ring 5 d and an end portion located in the vicinity of the neck portion 4 a of the outer ring type rotating shaft 4. Intervening in.

  The outer ring type rotating shaft 4 has a through hole 7 that passes through a portion (hereinafter referred to as a neck portion) 4a to which the rotating anode 3 is fixed. The through hole 7 is useful for discharging the gas generated due to heat generated by the rotation of the outer ring type rotating shaft 4 to the outside of the X-ray tube main body 2 (that is, inside the vacuum envelope).

  More specifically, the through-hole 7 is supplied between the outer ring type rotating shaft 4, that is, the fixed shaft 5 into which the gas generated due to the heat caused by the rotation of the rotating anode 3 is inserted inside the outer ring type rotating shaft 4. The liquid metal lubricant is formed in a predetermined shape and an inner diameter capable of preventing the liquid metal lubricant from being pushed out. That is, by providing the through hole 7, the space defined between the first and second spiral grooves 5a and 5b and the lubricant holding portion 5c and the inner wall of the outer ring type rotating shaft 4 has a non-sealing structure. . In other words, the hydrodynamic slide bearing 6 defined by the fixed shaft 5, the liquid metal lubricant, and the outer ring type rotating shaft 4 has a structure released from the outside of the bearing. The inner diameter of the through hole 7 is governed by the rotational speed of the rotary anode 3, the distance between the outer ring type rotary shaft 4 and the fixed shaft 5, or the characteristics (composition) of the liquid metal lubricant. 0.1 to 0.5 mm.

  Due to this non-sealed (released) structure, the gas generated in the vicinity indicated by symbol A in FIG. 1 is discharged from the through hole 7 to the outside of the hydrodynamic slide bearing. Therefore, the liquid metal lubricant is prevented from being pushed out of the bearing due to an increase in the internal pressure of the dynamic pressure type slide bearing 6 due to the influence of gas generated in the dynamic pressure type slide bearing 6. The thrust ring 5d side of the fixed shaft 5 is often a non-hermetic structure because of the structure of the thrust ring 5d. Therefore, the present invention is mainly applied to the neck 4a side of the outer ring type rotating shaft 4.

  When the rotary anode X-ray device 1 described above is in operation, the outer ring type rotary shaft 4 is rotated by providing a predetermined magnetic field from a stator (not shown) to the outer ring type rotary shaft 4. By rotating the outer ring type rotating shaft 4, the disc-shaped rotating anode 3 provided integrally with the outer ring type rotating shaft 4 is rotated at a predetermined speed.

  In this state, the target layer 3a of the disk-shaped rotating anode 3 is irradiated with an electron beam from an electron source (not shown), whereby X-rays are emitted from the target layer 3a. At this time, since the liquid metal lubricant and the portion in contact with the liquid metal lubricant function as the hydrodynamic slide bearing 6, X-rays emitted from the target layer 3a of the rotating anode 3 pass through a vacuum envelope (not shown). Thus, the predetermined position of the target (irradiation target) is accurately irradiated. Further, the gas generated inside the hydrodynamic slide bearing 6 is released through the through hole 7 to the inside of the vacuum envelope (outside the X-ray tube main body 2). The gas (impurity element) released into the vacuum envelope is adsorbed by an impurity recovery mechanism (not shown) provided in the vacuum envelope, for example, a getter.

  As described above, the through-hole 7 is provided in the neck portion 4 a of the outer ring type rotating shaft 4 that supports the rotating anode 3, so that the clearance between the outer ring type rotating shaft 4 and the fixed shaft 5 of the hydrodynamic slide bearing 6 is provided. The supplied liquid metal lubricant can be prevented from being pushed out of the bearing 6 by the gas generated inside the bearing 6. Accordingly, seizure and wear of the bearing 6 are suppressed, and the durability of the bearing 6 is improved.

  As a result, the X-ray tube main body 2 provided inside the vacuum envelope is reduced from becoming inoperable due to damage (seizure or wear) of the bearing 6, and medical diagnosis using the X-ray tube device 1. The life of the device and the non-destructive inspection device becomes long.

  FIG. 2 illustrates an example of another embodiment of the rotary anode X-ray tube apparatus shown in FIG. In addition, the same code | symbol is attached | subjected to the structure same as having shown in FIG. 1, and detailed description is abbreviate | omitted. In addition, a configuration similar to the configuration shown in FIG.

  As shown in FIG. 2, the X-ray tube main body 12 has a disk-shaped rotating anode 3, an outer ring rotating shaft 14, and a fixed shaft 15. 2, the vacuum envelope is omitted as in FIG. 1, and only the X-ray tube main body 12 is shown.

  The fixed shaft 15 is formed with first and second spiral grooves 5a, 5b and a lubricant holding portion 5c, each of which is given a specific direction along the axial direction. In addition, the liquid metal lubricant is supplied and the liquid metal lubricant is sealed by the thrust ring 5d. It should be noted that the liquid metal lubricant is in a direction perpendicular to the axis of the fixed shaft 15, in the gap between the thrust ring 5 d and the end portion located near the neck portion 14 a of the outer ring type rotary shaft 14. Intervening in. Accordingly, the hydrodynamic slide bearing 6 is constituted by the outer ring type rotating shaft 14, the fixed shaft 15 and the liquid metal lubricant.

  The neck portion 14a of the outer ring type rotating shaft 14 is substantially cylindrical with a through hole 17 having a predetermined inner diameter, and a protrusion 15e formed at the end of the fixed shaft 15 is inserted into the outer ring type rotating shaft 14. It can be rotated as a mold rotation axis. Note that the gap between the outer diameter of the protrusion 15e and the inner diameter of the neck 14a of the outer ring type rotating shaft 14 is the number of rotations of the rotating anode 3, the interval between the outer ring type rotating shaft 14 and the fixed shaft 15, or the liquid. Although governed by the characteristics (composition) of the metal lubricant, it is specified to be, for example, 50 μm or more and 200 μm or less. Similarly, the length of the protrusion 15e to be inserted into the neck 14a of the outer ring type rotating shaft 14, that is, the axial length of the protrusion 15e is fixed to the rotational speed of the rotating anode 3 and the outer ring type rotating shaft 14. Although it is governed by the distance between the shaft 15 and the characteristics (composition) of the liquid metal lubricant, it is preferably 5 mm or more and 20 mm or less. In other words, by appropriately setting the gap between the protrusion 15e and the inner wall of the through hole 17 of the neck 14a and the length of the protrusion 15e, it is more effective than the embodiment shown in FIG. In addition, the gas generated inside the hydrodynamic slide bearing 6 can be discharged to the outside of the X-ray tube main body 12 (that is, inside the vacuum envelope).

  As described above, the neck portion 14 a of the outer ring type rotating shaft 14 that supports the rotating anode 3 is formed into the cylindrical hole 17, and the protruding portion 15 e at the end of the fixed shaft 15 is provided with a predetermined gap in the cylindrical hole 17. Therefore, the liquid metal lubricant supplied to the gap between the outer ring type rotary shaft 14 and the fixed shaft 15 of the hydrodynamic slide bearing 6 is pushed out of the bearing 6 by the gas generated inside the bearing 6. Can be prevented. Accordingly, seizure and wear of the bearing 6 are suppressed, and the durability of the bearing 6 is improved.

  As a result, the X-ray tube main body 12 provided inside the vacuum envelope is reduced from becoming inoperable due to damage (seizure or wear) of the bearing 6, and medical diagnosis using the X-ray tube device 11. The life of the device and the non-destructive inspection device becomes long.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by variously modifying the constituent elements 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 above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment.

  As described above, according to the present invention, the durability of an outer ring rotating type rotary anode X-ray apparatus using a hydrodynamic slide bearing is improved, and X-rays having a predetermined intensity can be obtained stably over a long period of time. Accordingly, the life of the medical diagnostic apparatus and non-destructive inspection apparatus using the rotating anode type X-ray tube becomes long.

Schematic for demonstrating an example of the X-ray tube of embodiment of this invention. Schematic for demonstrating an example of the X-ray tube of other embodiment of this invention. Schematic for demonstrating the well-known X-ray tube which has a dynamic-pressure-type slide bearing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,11 ... Rotating anode X-ray tube apparatus, 2,12 ... X-ray tube main body, 3 ... Disk-shaped rotating anode, 4,14 ... Outer ring type rotating shaft, 4a, 14a ... Neck part, 5,15 ... Fixed shaft, 5a , 5b ... spiral groove, 5c ... lubricant holding part, 5d ... thrust ring, 15e ... projection, 6 ... hydrodynamic slide bearing, 7 ... through hole, 17 ... through hole.

Claims (5)

A rotating anode that emits X-rays when irradiated with an electron beam, an outer ring rotating type rotating body that is connected to the rotating anode, and a predetermined position inside the rotating body that rotates the rotating body A fixed shaft that supports the rotating body, and a liquid metal lubricant that is supplied to a gap between the rotating body and the fixed shaft. The rotating body, the fixed shaft, and the liquid metal lubricant are hydrodynamic. In a rotating anode X-ray tube device that functions as a sliding bearing,
The rotary anode type X-ray tube device characterized in that a portion of the rotating body to which the rotating anode is connected is formed so that gas generated inside the hydrodynamic slide bearing can be discharged to the outside of the bearing.   A portion of the rotating body to which the rotating anode is connected has a through-hole having a diameter capable of discharging the gas generated inside the hydrodynamic slide bearing without discharging the liquid metal lubricant to the outside. The rotating anode type X-ray tube according to claim 1.   A portion of the rotating body to which the rotating anode is connected has a cylindrical shaft defined by an inner diameter capable of discharging the gas generated inside the hydrodynamic slide bearing without discharging the liquid metal lubricant to the outside. 2. The rotary anode X-ray tube according to claim 1, further comprising: a projection portion having a diameter which is a predetermined interval with respect to the inner diameter of the shaft portion and the shaft portion. A fixed shaft with one end formed non-fixed;
An anode member that emits X-rays by being irradiated with an electron beam is held on the non-fixed end side from the non-fixed end side of the fixed shaft. An outer ring type rotating shaft;
A liquid metal lubricant interposed between the fixed shaft and the outer ring type rotating shaft;
An exhaust hole provided on the non-fixed end side of the outer ring type rotation shaft and capable of exhausting gas generated in the vicinity of the liquid metal lubricant;
A rotating anode type X-ray tube characterized by comprising: A fixed shaft;
An anode member that has a cylindrical neck portion and emits X-rays when the neck portion is irradiated with an electron beam is fixed, and the fixed shaft is fixed to the fixed shaft from one end side of the fixed shaft. An outer ring type rotation shaft positioned so as to be rotatable around the shaft;
A liquid metal lubricant interposed between the fixed shaft and the outer ring type rotating shaft;
A predetermined length is given to the one end side of the fixed shaft with a predetermined gap with respect to the inner diameter of the cylindrical portion of the neck portion of the outer ring rotating shaft and to the axial direction of the fixed shaft. A protrusion capable of exhausting gas generated in the vicinity of the liquid metal lubricant,
A rotating anode type X-ray tube characterized by comprising:

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