JP2009238477A - Rotating anode x-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anode rotating type X-ray tube with high reliability in which a rotor can make a stable rotation movement. <P>SOLUTION: In the X-ray tube, a cylindrical rotor includes a cylindrical inner face and a fixed axle is inserted into the hollow cylinder to support the rotor rotatably. A pillar-shape bearing part is installed in the fixed axle and includes an opposed face opposed to the cylinder inner face. A bearing groove is formed in the opposed face and a dynamic bearing is formed on the opposed face by lubricant filled in the gap. At both ends of the pillar-shape bearing part, a thin structure is provided at the end of the pillar-shape bearing part by a circular circumference groove formed by cut-out and a cylindrical flange part at the outer periphery of the circular circumference groove. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

    The present invention relates to a rotary anode type X-ray tube having a dynamic pressure sliding bearing using a liquid lubricant.

    In general, X-ray tube apparatuses are used in medical diagnosis systems, industrial diagnosis systems, and the like. The X-ray tube device includes a rotary anode X-ray tube that emits X-rays, a stator coil, and a housing that houses the rotary anode X-ray tube and the stator coil.

  The rotary anode type X-ray tube is provided with a fixed shaft, a rotary body rotatably provided on the fixed shaft, rotated by a magnetic field from the stator coil, and a rotary body provided with a joint at the end of the rotary body. An anode target rotated together with the body, a cathode disposed opposite to the anode target, projecting an electron beam onto the anode target and generating X-rays from the anode target, and a vacuum containing these rotor, anode target and cathode It consists of an envelope. A dynamic pressure plain bearing filled with a liquid metal as a lubricating liquid is formed in the gap between the fixed shaft and the rotating body. When the rotating body rotates, the liquid metal between the fixed shaft and the rotating body has a dynamic pressure. The generated rotating body is rotatably supported.

  As disclosed in Patent Document 1 as an example, a conventional dynamic pressure plain bearing has a groove for drawing a liquid lubricant during rotation, for example, a spiral groove in a herringbone pattern, formed on a fixed shaft. The rotating body is fitted to a cylindrical member constituting the fixed shaft, and a cylindrical bearing facing portion in which a small gap is provided between the cylindrical member and the cylindrical inner surface of the cylindrical member, and between the bearing facing portions adjacent to each other. The shaft has a smaller diameter than the cylindrical bearing facing portion, a relatively large gap is provided between the cylindrical member and the cylindrical inner surface, and a small diameter portion having a smaller diameter than the bearing facing portion. ing. The above-mentioned spiral groove is formed in the cylindrical bearing facing portion to form a hydrodynamic sliding bearing, and the space between the small diameter portion and the cylindrical inner surface of the cylindrical member prevents seizure of the cylindrical bearing facing portion. Therefore, it has a function of sufficiently storing the lubricant. Examples of such plain bearings are not limited to Patent Document 1, but are disclosed in Patent Documents 2 and 3.

Further, as disclosed in Patent Document 4, as a plain bearing in other fields other than the X-ray tube device, there is a main bearing of an internal combustion engine. In the main bearing of the internal combustion engine, a bearing is used to prevent fatigue damage of the bearing. A notch (groove) is provided at the end so that the shaft can be easily deformed against contact with one piece.
Japanese Patent No. 3139873 JP 2001-276034 A JP 2005-69375 A JP-A-10-122229

  In recent years, in the CT apparatus, as the helical scan speeds up, the centrifugal force acting on the X-ray tube increases, and the probability that the fixed shaft that supports the rotating anode deforms increases. With the deformation of the fixed shaft, there is a concern that in the bearing portion where only a small gap is provided, the rotating body and the fixed shaft come into contact with each other and seizure occurs.

  As a solution to the above problem, a method of changing the arrangement of the bearing portion from a region where the deformation of the fixed shaft is likely to occur to a region where the deformation of the fixed shaft is smaller is assumed. However, if the arrangement of the bearing portion is changed, the total length of the anode becomes longer. As the total length becomes longer, the amount of deformation of the fixed shaft when the centrifugal force is applied further increases, and the weight of the X-ray tube itself increases. There is a problem that becomes. Therefore, an improvement in the bearing structure is desired rather than changing the arrangement of the bearing portions.

  Further, conventionally, there has been a problem that the rotating body and the fixed shaft are gnawed (contact each other) at the end of the bearing portion due to the swinging of the rotating body and the deformation of the fixed shaft. There is also a problem that galling (contact) occurs due to insufficient supply of liquid. When seizure occurs due to galling, the rotating body cannot rotate.

  The present invention has been made in order to solve the above-described problems, and the object thereof is to provide a reliable anode rotation capable of stable rotational movement of the rotating body without causing the rotating body and the fixed shaft to be in contact with each other. It is to provide a type X-ray tube.

According to this invention,
A rotating anode comprising a target that is irradiated with an electron beam to generate X-rays;
A rotating body that supports the rotating anode and has a cylindrical inner surface that defines a hollow cylindrical portion;
A fixed shaft that is inserted into the hollow cylindrical portion and rotatably supports the rotating body, and has a columnar bearing portion provided with an opposing surface facing the cylindrical inner surface with a gap therebetween;
A bearing groove formed on at least one of the cylindrical inner surface and the facing surface, a dynamic pressure bearing formed on the facing surface with a lubricant filled in the gap, and at least both ends of the columnar bearing portion A thin-walled structure provided at the end of the columnar bearing portion with a circumferential groove formed on one side and a cylindrical flange on the outer periphery of the circumferential groove;
A rotary anode type X-ray tube is provided.

Moreover, according to this invention,
A rotating anode comprising a target that is irradiated with an electron beam to generate X-rays;
A rotating body that supports the rotating anode and has a cylindrical inner surface that defines a hollow cylindrical portion;
First and second columnar bearing portions, which are inserted into the hollow cylindrical portion and support the rotating body so as to be rotatable, and have opposed surfaces facing the cylindrical inner surface with a gap therebetween, and the first Between the first and second columnar bearing portions, there is a small diameter shaft portion smaller in diameter than the columnar bearing portion, and a storage portion for storing a lubricant is provided between the small diameter shaft portion and the cylindrical inner surface. A fixed shaft;
A bearing groove formed on at least one of the cylindrical inner surface and the opposed surface, a dynamic pressure bearing formed on the opposed surface with the lubricant filled in the gap, and the first and second columnar shapes A thin groove structure provided at the end of the columnar bearing portion at a circumferential groove formed in a cutout at least one of both ends of the bearing portion and a cylindrical flange on the outer periphery of the circumferential groove;
A rotary anode type X-ray tube is provided.

  A notch is provided in the end face of the cylindrical bearing facing portion, and the end portion of the bearing facing portion is formed in a thin structure. Therefore, the thin-walled structure is easily elastically deformed by the increase in the pressure of the lubricating liquid due to the approach between the rotating body and the cylindrical bearing facing portion, and the gap between the rotating body and the cylindrical bearing facing portion can be maintained. As a result, it is possible to prevent the rotating body and the fixed shaft from coming into contact and seizing. This structure can also prevent the fixed shaft and the rotating shaft from galling even if the rotating body swings around. Also, by providing a liquid supply hole in the thin structure of the bearing facing part, the liquid lubricant to the bearing part is smoothly supplied through the liquid supply hole, and the rotating body and the fixed shaft are It is possible to prevent galling. Therefore, according to the present invention, the rotating body can be stably rotated without squeezing the rotating body and the fixed shaft, and a highly reliable anode rotating X-ray tube can be provided.

  Hereinafter, an anode rotating X-ray tube according to an embodiment of the present invention will be described with reference to the drawings as necessary.

  FIG. 1 shows a rotary anode X-ray tube having a cantilever bearing structure according to an embodiment of the present invention. The rotary anode type X-ray tube 1 is housed in a housing (not shown) of an X-ray tube device together with a stator coil 2 that generates a rotating magnetic field. The rotary anode type X-ray tube 1 includes a vacuum envelope 4 which is simplified and shown by a broken line, and a stator coil 2 for generating a rotating magnetic field is disposed on the outer periphery of the vacuum envelope 4. The vacuum envelope 4 is maintained in a vacuum, and a fixed shaft 10 is disposed in the vacuum envelope 4 along the central axis 6 of the rotary anode X-ray tube 1. 14 is fixed to the fixed portion 8 and the fixed shaft 10 is cantilevered. The vacuum envelope 4 is hermetically sealed to the fixed portion 8. The fixed shaft 10 is fitted into a bottomed cylindrical rotating body 50, and the rotating body 50 is rotatably supported on the fixed shaft 10.

  A cylindrical motor rotor 53 made of a conductive material such as copper that rotates together with the rotating body 50 is disposed on the outer periphery of the rotating body 50 so as to face the stator coil 2, and this motor rotor is rotated by a rotating magnetic field from the stator coil 2. A rotational force is generated from 53 and the rotating body 50 is supported by the fixed shaft 10 and rotated. A rotary joint 42 extends from the bottomed portion (end) of the rotary body 50 along the central axis 6, and the anode target 40 is connected to the rotary joint 42. Therefore, the anode target 40 is rotated with the rotation of the rotating body 50. A cathode 30 is disposed opposite to the anode target 40, and an electron beam emitted from the cathode 30 is projected onto the rotated anode target 40 to generate X-rays. As shown in FIG. 1, the cathode 30, the anode target 40, the rotating body 50, the fixed body 50, and the motor rotor 53 are stored in the vacuum envelope 4.

  The fixed shaft 10 has a cylindrical bearing facing portion 16 having a diameter larger than that of the shaft portion 14, and the outer peripheral surface 11 of the bearing facing portion 16 is opposed to the cylindrical inner surface 51 of the rotating body 50. A liquid metal lubricant 20 is filled in the gap G between the columnar bearing facing portions 16. Further, in order to prevent the liquid metal lubricant 20 filled in the gap G from leaking into the opening-side cylindrical inner surface of the bottomed cylindrical rotating body 50, the shaft portion 14 of the rotating body 10 is liquid-tight. A maintaining seal 54 is provided. The seal portion 54 is formed of a labyrinth seal, has a very small gap with the shaft portion 14, is not in direct contact with the shaft portion 14, and does not provide a complete seal with the shaft portion 14. Therefore, the inside of the dynamic pressure slide bearing is maintained in a vacuum as in the vacuum envelope 4. The seal portion 54 is provided with irregularities, but the recess of the seal portion 54 has a function of retaining the leaked liquid metal.

  In addition, since a bearing is a part which receives an axis | shaft as a term, it has indicated the cylindrical inner surface (rotary body inner surface) in the exact meaning. In this specification, the portion of the fixed shaft that faces the cylindrical inner surface (rotor inner surface) of the bearing is referred to as a bearing facing portion.

  The liquid metal lubricant 20 has a function as a lubricant for the dynamic pressure sliding bearing, and the liquid metal lubricant 20 generates dynamic pressure when the rotating body 50 is rotated. On the outer peripheral surface 11 of the cylindrical bearing facing portion 16 facing the cylindrical inner surface 51 of the rotating body 50, a groove for drawing the liquid metal lubricant 20 into the dynamic pressure sliding bearing (radial sliding bearing), for example, a herringbone arrangement. A spiral groove is formed. Therefore, the rotating body 50 is supported in the radial direction (radial direction) by the cylindrical bearing facing portion 16 of the fixed shaft 10. Instead of forming a groove on the outer peripheral surface 11 of the cylindrical bearing facing portion 16, a radial sliding bearing is similarly provided between the bearing facing portion 16 and the rotating body 50 even if a groove is formed on the cylindrical inner surface 51 of the rotating body 50. Can be provided.

  FIG. 2 shows an enlarged view of the bearing structure shown in FIG. As shown in FIG. 2, the columnar bearing facing portion 16 has a columnar end portion 17A having substantially the same diameter as the shaft portion 14 on the free end side and a cylindrical flange portion 17B facing the end portion 17A. Yes. Further, the cylindrical bearing facing portion 16 has a cylindrical end portion 17C having the same diameter as the shaft portion 14 on the fixed end side, that is, the shaft portion 14 side, and a cylindrical flange portion 17D facing the end portion 17C. is doing. The columnar end portion 17A and the cylindrical flange portion 17B are formed by forming circumferential grooves 60 and 64 (notches) coaxial with the central axis 6 on the end surface on the free end side of the columnar bearing facing portion 16. Similarly, the cylindrical end portion 17C and the cylindrical flange portion 17D are formed by forming a circumferential groove 62 (notch) coaxial with the central shaft 6 on the end surface on the fixed end side of the cylindrical bearing facing portion 16. The A large number of liquid supply holes 80 arranged along the circumference of the flange portions 17B and 17D are formed. The flange portions 17B and 17D are thinner than the cylindrical bearing facing portion 16 and are supplied from the lubricating liquid 20. It is formed in a thin-walled structure 70 that can be elastically deformed by the applied pressure. Thus, when both ends of the cylindrical bearing facing portion 16 constituting the radial bearing are formed in the thin-walled structure 70, this approach is provided when the cylindrical inner surface 51 of the rotating body 50 approaches the bearing facing surface 11. As a result, the pressure of the lubricating liquid 20 is increased, and the thin-walled structure 70 is easily elastically deformed. Based on this elastic deformation, a gap is widened between the cylindrical inner surface 51 and the bearing facing surface 11, and direct contact can be avoided and galling can be prevented. Further, by providing the thin-walled structure 70 with the liquid supply hole 80 that connects the bearing gap G and the circumferential grooves 60 and 64 (notches), the lubricating liquid accumulated in the circumferential grooves 60 and 64 (notches) when stationary. Can be supplied from the liquid supply hole 80 to the bearing gap G. Therefore, it is possible to prevent the bearing portion from being galled at the time of starting the rotating body.

  FIG. 3 shows an X-ray tube in which a fixed shaft according to another embodiment of the present invention is supported at both ends, and FIG. 4 shows a bearing structure of the fixed shaft. In the X-ray tube shown in FIG. 3 and the bearing structure shown in FIG. 4, the portions denoted by the same reference numerals as those shown in FIGS. 1 and 2 indicate the same parts or members and the description thereof is omitted. As shown in FIG. 3, the shaft portions 14A and 14B of the fixed shaft 10 are supported at both ends, the rotating body 50 is formed in a substantially cylindrical shape, and the anode target 40 is fixedly supported at the center thereof. Then, seal portions 54A and 54B are provided on the shaft portions 14A and 14B of the rotating body 10 to keep them liquid-tight.

  In FIG. 3, the vacuum envelope 4 is omitted for the sake of simplicity, but the cathode 30, the anode target 40, the rotating body 50, and the fixed body are fixed in the vacuum envelope 4 as in FIG. 1. Note that the body 50 and motor rotor 53 are stored.

  Even in a structure in which the rotating body 50 is supported at both ends as shown in FIG. 3, the cylindrical end portions 17A and 17C and the cylinder are formed at both ends of the cylindrical bearing facing portion 16 as shown in FIG. You may have the shape collar parts 17B and 17D. The cylindrical end portions 17A and 17C and the cylindrical flange portions 17B and 17D are formed by forming circumferential grooves 60 and 64 (notches) coaxial with the central axis 6 on the end surface of the cylindrical bearing facing portion 16. The A large number of liquid supply holes 80 arranged along the circumference of the flange portions 17B and 17D are formed. The flange portions 17B and 17D are thinner than the cylindrical bearing facing portion 16 and are supplied from the lubricating liquid 20. It is formed in a thin-walled structure 70 that can be elastically deformed by the applied pressure. Thus, when both ends of the cylindrical bearing facing portion 16 constituting the radial bearing are formed in the thin-walled structure 70, this approach is provided when the cylindrical inner surface 51 of the rotating body 50 approaches the bearing facing surface 11. As a result, the pressure of the lubricating liquid 20 is increased, and the thin-walled structure 70 is easily elastically deformed. Based on this elastic deformation, a gap is widened between the cylindrical inner surface 51 and the bearing facing surface 11, and direct contact can be avoided and galling can be prevented. Further, by providing the thin-walled structure 70 with the liquid supply hole 80 that connects the bearing gap G and the circumferential grooves 60 and 64 (notches), the lubricating liquid accumulated in the circumferential grooves 60 and 64 (notches) when stationary. Can be supplied from the liquid supply hole 80 to the bearing gap G. Therefore, it is possible to prevent galling (contact) between the bearing portion and the rotating portion when the rotating body is started.

  FIG. 5 shows a modification of the bearing structure of the rotary anode X-ray tube shown in FIGS. Although FIG. 5 is drawn as a structure in which the fixed shaft 10 is both supported as in FIG. 3, the structure may naturally be applied to a structure in which the fixed shaft 10 is cantilevered as in FIG. 2. It is clear. Further, in the bearing structure shown in FIG. 5, the parts denoted by the same reference numerals as those shown in FIG. 2 indicate the same parts or members, and the description thereof is omitted.

  In the bearing structure of the rotary anode X-ray tube shown in FIG. 5, the cylindrical bearing facing portion 16 of the fixed shaft 10 is separated into a pair of cylindrical facing portions 16A and 16B along the central axis 6, and this circle A lubricating liquid storage portion 12 is formed as a recess between the columnar facing portions 16A and 16B. Cylindrical ends 17A and 17E and cylindrical flanges 17B and 17F are also provided at both ends of the columnar facing portion 16A, and columnar ends 17D and 17F are also provided at both ends of the columnar facing portion 16B. 17E and cylindrical flanges 17D and 17G are provided. The cylindrical end portions 17A, 17C, and 17E and the cylindrical flange portions 17B, 17D, 17F, and 17G have circumferential grooves 60, 64, 62, and 66 coaxial with the central axis 6 on the end surface of the cylindrical bearing facing portion 16. It is formed by forming. The flange portions 17B, 17D, 17F, and 17G are formed with a large number of liquid supply holes 80 arranged along the circumference thereof, and the flange portions 17B, 17D, 17F, and 17G are compared with the cylindrical bearing facing portion 16. The thin structure 70 is thin and can be elastically deformed by the pressure applied from the lubricating liquid 20. When both end portions of the cylindrical bearing facing portion 16 constituting the radial bearing are formed in the thin wall structure 70 as described above, when the cylindrical inner surface 51 of the rotating body 50 approaches the bearing facing surface 11, this approach is performed. As a result, the pressure of the lubricating liquid 20 is increased, and the thin-walled structure 70 is easily elastically deformed. Based on this elastic deformation, a gap is widened between the cylindrical inner surface 51 and the bearing facing surface 11, and direct contact can be avoided and galling (contact) can be prevented. Further, by providing the thin-walled structure 70 with a liquid supply hole 80 that connects the bearing gap G and the circumferential grooves 60 and 64 (notches), the lubricating liquid that has accumulated in the circumferential grooves 60, 62, 64, and 66 when stationary. Can be supplied from the liquid supply hole 80 to the bearing gap G. Therefore, it is possible to prevent the bearing portion from being galled at the time of starting the rotating body.

  A space between the small diameter portion 12 corresponding to the columnar end portion 17E and the cylindrical inner surface 51 has a function of becoming a space for storing the lubricating liquid when the rotating body is stationary. Since the liquid supply hole 80 communicates with a portion that stores the lubricating liquid, the lubricating liquid can be smoothly supplied to the bearing portion, and galling due to a shortage of the lubricating liquid in the bearing portion can be prevented.

  6 and 7 show a modification of the bearing structure of the rotary anode X-ray tube in which the fixed shaft shown in FIG. 2 is cantilevered. In the bearing structure shown in FIGS. 6 and 7, the parts denoted by the same reference numerals as those shown in FIGS. 2, 4, and 5 indicate the same parts or members and the description thereof is omitted.

  In the structure shown in FIG. 6, a thrust ring 90 having a larger diameter than the cylindrical bearing facing portion 16 of the fixed shaft 10 is joined to the fixed shaft 10, and the rotating body is formed by the end surface of the thrust ring 90 and the end surface of the seal portion 54. A thrust bearing structure 91 that supports 50 in the thrust direction is configured. A herringbone pattern groove is radially disposed around the central axis 6 on either the end face of the thrust ring 90 or the end face of the seal portion 54, and the liquid metal lubricant 20 drawn into the groove moves in the thrust direction. Pressure is generated and the rotating body 50 is supported in the thrust direction along the central axis 6. In the structure shown in FIG. 6, since the thrust ring 90 is fixed to the fixed side end face of the bearing facing portion 16B, it is noted that the circumferential groove 64 is not formed and the cylindrical flange portion 17D is not provided. I want. In the structure shown in FIG. 6, instead of the circumferential groove 64, a circumferential groove (notch) 68 is formed on the fixed-side end surface of the rotating body 50 facing the thrust ring 90, and the flange portion is formed on the end surface of the rotating body 50. 17H is preferably provided. A thin-wall structure 72 similar to the thin-wall structure 70 formed on the cylindrical bearing facing portion 16 is formed on the end surface of the rotating body 50 by the circumferential groove (notch portion) 68 and the flange portion 17H. The thin-walled structure 72 can prevent galling due to the rotation of the rotating body 50 and the deformation of the fixed shaft due to the centrifugal force, as in the case where the notch is provided on the side surface of the cylindrical bearing facing portion 16.

  In the structure shown in FIG. 7, a thrust bearing structure 91 that supports the rotating body 50 in the thrust direction is configured by the fixed-side end surface of the fixed shaft 10 and the end surface of the seal portion 54. A herringbone pattern groove (not shown) is radially arranged around the central axis 6 on either the fixed-side end face of the fixed shaft 10 or the end face of the seal portion 54, and the liquid drawn into this groove Dynamic pressure is generated by the metal lubricant 20, and the rotating body 50 is axially supported in the thrust direction along the central axis 6. In the structure shown in FIG. 7, since the fixed side end face of the cylindrical bearing facing portion 16B forms the thrust bearing structure 91, the circumferential groove 64 is not formed, and the cylindrical flange portion 17D is not provided. Please note that. In the structure shown in FIG. 7, instead of the circumferential groove 64, a circumferential groove (notch) 68 is formed on the end surface of the rotating body 50 facing the end surface of the seal portion 54, and the fixed side end surface of the rotating body 50 is formed. It is preferable that the flange portion 17H is provided. A thin-wall structure 72 similar to the thin-wall structure 70 formed on the cylindrical bearing facing portion 16 is formed on the end surface of the rotating body 50 by the circumferential groove (notch portion) 68 and the flange portion 17H. This thin structure 72 prevents galling due to the rotation of the rotating body 50 and deformation of the fixed shaft due to centrifugal force, as in the case where a circumferential groove (notch) is provided on the end face of the cylindrical bearing facing portion 16. be able to.

  As shown in FIG. 8, also in the rotary anode X-ray tube having a both-end fixed shaft, the thin-walled structures 72A and 72B are provided on both end surfaces of the cylindrical bearing facing portion 16 in the same manner as the bearing structure shown in FIG. It is preferable. As shown in FIG. 8, seal portions 54A, 54B are attached to both ends of the rotating body 50, and thrust bearing structures 91A, 91B are provided between the end surfaces of the seal portions 54A, 54B and the end surface of the cylindrical bearing facing portion 16. It is configured. Further, it is preferable that circumferential grooves (notches) 68A and 68B are formed on the end surface of the rotating body 50 facing the end surface of the seal portion 54, and the flanges 17H and 17I are provided on the fixed-side end surface of the rotating body 50. . These circumferential grooves (notches) 68A, 68B and flanges 17H, 17I form thin structures 72A, 72B similar to the thin structure 70 formed on the cylindrical bearing facing portion 16 on both end faces of the rotating body 50. The As with the thin-walled structures 772A and 72B, as with the case where circumferential grooves (notches) are provided on both end surfaces of the cylindrical bearing facing portion 16, galling due to the rotation of the rotating body 50 and deformation of the fixed shaft due to centrifugal force. Can be prevented.

  In the structure shown in FIG. 8, a thrust ring 90 may be provided in the same manner as shown in FIG. 6 in order to constitute the thrust bearing structures 91A and 91B. In the structure shown in FIG. 8, a notch structure cannot be provided on the end surface of the cylindrical bearing facing portion 16 that faces the end surfaces of the seal portions 54A and 54B. Circumferential grooves (notches) are provided on both end faces 68A and 68B of the bearing portion facing the cylindrical bearing facing portion 16 where no circumferential grooves (notches) are provided, and the bearing ends are thin-walled structures 72A and 72B. It can be. With this structure, similarly to the case where a circumferential groove (notch) is provided on the end face of the cylindrical bearing facing portion 16, it is possible to prevent galling due to the rotation of the rotating body or deformation of the fixed shaft 10 due to centrifugal force. it can.

  FIG. 9 shows a modification in which the liquid supply hole 80 is provided only in the flanges 17G and 17F extending toward the lubricating liquid storage unit 12 in the structure shown in FIG. Since the thrust bearing structures 91A and 91B or the seals 54A and 54B are attached to both sides of the bearing columnar facing portion 16 constituted by the cylindrical bearing facing portions 16A and 16B, the lubricating liquid that accumulates in the notch structures 68A and 68B when stationary. Is a small amount compared to the lubricating liquid storage unit 12. On the other hand, a large amount of the lubricating liquid 20 can be stored in the lubricating liquid storage unit 12. Therefore, only the liquid supply hole 80 communicating with the lubricating liquid storage section 12 effective for supplying the lubricating liquid 20 may be provided in the flange portions 17G and 17F.

  10 shows a bearing structure having an uneven groove structure 13 that draws the lubricating liquid 20 into the bearing portion, and FIG. 11 shows the bearing structure 13 shown in FIG. 10 in an enlarged manner. In the groove structure 13, the herringbone pattern groove is formed on a flat surface as described above, and the bearing facing surface 11 is provided, and the bearing facing surface 11 is formed with irregularities. Here, when the liquid supply hole 80 is formed in the convex portion of the groove structure 13, the ability to apply pressure in the bearing structure 13 may be reduced. Therefore, in the groove structure 13 shown in FIGS. 10 and 11, the liquid supply hole 80 is provided in the concave portion of the groove structure 13.

  FIG. 12 shows a state where the rotating shaft of the rotating body 50 is eccentric from the central axis 6 of the fixed shaft 10 when the centrifugal force F acts on the X-ray tube 1 on the bearing structure 13. Since the rotating body 50 is eccentric along the centrifugal force F, the cylindrical inner surface 51 of the rotating body 50 to which the centrifugal force F acts is the cylindrical bearing facing portion 16 that is directed in the direction of the centrifugal force F. It is separated from the surface 11 and is brought closer to the surface 11 of the cylindrical bearing facing portion 16 that is directed in the direction opposite to the centrifugal force F. That is, the gap G is not uniform around the bearing facing surface 11, the gap G2 on the opposite side to the direction of action of the centrifugal force F is smaller than the gap G1 on the side of the action direction of the centrifugal force F, and the cylinder of the rotating body 50 The inner surface 51 is brought closer to the bearing facing surface 11. In such a state, if the liquid supply hole 80 is provided on the gap G2 side, the ability to apply pressure in the bearing structure 13 may be reduced. Accordingly, in the groove structure 13 shown in FIG. 12, the liquid supply hole 80 is provided only in the flange portions 17B, 17D, 17F, and 17G facing the gap G1 whose interval is increased by application of centrifugal force, compared to the gap G1. The liquid supply holes 80 are not provided in the flange portions 17B, 17D, 17F, and 17G facing the gap G2 where the distance is reduced. That is, the liquid supply hole 80 is provided on the gap G1 side where the pressure increase of the lubricating liquid 20 is small.

  In FIGS. 2 and 4 to 12, the space 18 in the rotating body 50 drawn in white around the fixed shaft 10 is a vacuum space. The gap between the fixed shaft 10 and the rotating body 50 is occupied by the liquid metal and vacuum space of the bearing lubricant 20. Here, the vacuum space has a slight gap in the seal portion 54 and communicates with the vacuum space in the vacuum envelope 4 and is maintained in a vacuum. 2 and 4 to 12 show a state in which the rotating body 50 is rotating. On the inner peripheral surface of the rotating body 50, the liquid metal 20 is directed outward by the centrifugal force generated by the rotation of the rotating body 50. A vacuum space is formed in the vicinity of the vicinity of the center of the periphery of the fixed shaft 10.

  As described above, in the X-ray tube, a notch is provided in the end surface of the cylindrical bearing facing portion, and the end portion of the bearing facing portion is formed in a thin structure. Therefore, the thin-walled structure is easily elastically deformed by the increase in the pressure of the lubricating liquid due to the approach between the rotating body and the cylindrical bearing facing portion, and the gap between the rotating body and the cylindrical bearing facing portion can be maintained. As a result, it is possible to prevent the rotating body and the fixed shaft from coming into contact and seizing. This structure can also prevent the fixed shaft and the rotating shaft from galling even if the rotating body swings around. Also, by providing a liquid supply hole in the thin structure of the bearing facing part, the liquid lubricant to the bearing part is smoothly supplied through the liquid supply hole, and the rotating body and the fixed shaft are It is possible to prevent galling. Therefore, the rotating body can be stably rotated without being gnawed by the rotating body and a highly reliable anode rotating X-ray tube can be provided.

1 is a cross-sectional view schematically showing a structure of a rotary anode type X-ray tube having a cantilever bearing structure according to an embodiment of the present invention. It is sectional drawing which shows roughly the bearing structure of the rotating anode type | mold X-ray tube shown by FIG. It is sectional drawing which shows roughly the structure of the rotating anode type | mold X-ray tube which has the both-ends bearing structure which concerns on other embodiment of this invention. It is sectional drawing which shows roughly the bearing structure of the rotating anode type | mold X-ray tube shown by FIG. It is sectional drawing which shows roughly the modification of the bearing structure of the rotating anode type | mold X-ray tube shown by FIG. It is sectional drawing which shows roughly the bearing structure of the rotary anode type | mold X-ray tube provided with the cantilever fixed axis | shaft which concerns on the other Example of this invention. It is sectional drawing which shows roughly the modification of the bearing structure of a rotating anode type | mold X-ray tube provided with the cantilever fixed axis | shaft shown by FIG. It is sectional drawing which shows roughly the bearing structure of the rotary anode type | mold X-ray tube provided with the both-ends fixed axis | shaft which concerns on other Example of this invention. It is sectional drawing which shows roughly the modification of the bearing structure of a rotating anode type | mold X-ray tube provided with the both-ends fixed shaft shown by FIG. It is sectional drawing which shows roughly the other modification of the bearing structure of a rotating anode type | mold X-ray tube provided with the both-ends fixed shaft shown by FIG. It is sectional drawing which expands and shows a part of bearing structure shown by FIG. FIG. 9 is a cross-sectional view schematically showing still another modification of the bearing structure of the rotary anode type X-ray tube including the both-end fixed shaft shown in FIG. 8.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rotary anode type X-ray tube, 2 ... Stator coil, 4 . . 5. Vacuum envelope, . . 11. central axis, 10... Fixed shaft, 11... Bearing facing surface, 12. . . Shaft portion, 13 ... groove structure, 16. . . Cylindrical bearing facing part, 17A, 17B. . . Cylindrical collar, 17C, 17D. . . Cylindrical end, 20 ... Liquid metal lubricant, 30 ... Cathode, 40 ... Anode target, 42. . . Rotating joint, 50 ... Rotating body, 51 ... Cylinder inner surface, 53 ... Motor rotor, 54 ... Seal part, 60, 62, 64, 66, 68 ... Circumferential groove (notched part), 70 ... Thin wall structure, 80 ... Liquid supply Hole, 90 ... thrust ring, 91 ... thrust bearing structure, G, G1, G2. . . gap

Claims (12)

A rotating anode comprising a target that is irradiated with an electron beam to generate X-rays;
A rotating body that supports the rotating anode and has a cylindrical inner surface that defines a hollow cylindrical portion;
A fixed shaft that is inserted into the hollow cylindrical portion and rotatably supports the rotating body, and has a columnar bearing portion provided with an opposing surface facing the cylindrical inner surface with a gap therebetween;
A bearing groove formed on at least one of the cylindrical inner surface and the facing surface, a dynamic pressure bearing formed on the facing surface with a lubricant filled in the gap, and at least both ends of the columnar bearing portion A thin-walled structure provided at the end of the columnar bearing portion with a circumferential groove formed on one side and a cylindrical flange on the outer periphery of the circumferential groove;
A rotary anode X-ray tube comprising:     One end of the fixed shaft is fixed, and the rotating body is formed in a bottomed cylindrical shape. A seal portion for preventing leakage of the lubricant is provided between the rotating body and the fixed shaft. The rotating anode X-ray tube according to claim 1, wherein the rotating anode X-ray tube is provided.     The fixed shaft is fixed at both ends, and the rotating body is formed in a cylindrical shape having both ends open. A seal portion for preventing leakage of the lubricant is fixed to the fixed shaft at both openings of the rotating body. The rotary anode X-ray tube according to claim 1, which is provided between     The rotary anode type X-ray tube according to claim 1, wherein a liquid supply hole through which the lubricant passes is provided in the flange portion. A rotating anode comprising a target that is irradiated with an electron beam to generate X-rays;
A rotating body that supports the rotating anode and has a cylindrical inner surface that defines a hollow cylindrical portion;
First and second columnar bearing portions, which are inserted into the hollow cylindrical portion and support the rotating body so as to be rotatable, and have opposed surfaces facing the cylindrical inner surface with a gap therebetween, and the first Between the first and second columnar bearing portions, there is a small diameter shaft portion smaller in diameter than the columnar bearing portion, and a storage portion for storing a lubricant is provided between the small diameter shaft portion and the cylindrical inner surface. A fixed shaft;
A bearing groove formed on at least one of the cylindrical inner surface and the opposed surface, a dynamic pressure bearing formed on the opposed surface with the lubricant filled in the gap, and the first and second columnar shapes A thin groove structure provided at the end of the columnar bearing portion at a circumferential groove formed in a cutout at least one of both ends of the bearing portion and a cylindrical flange on the outer periphery of the circumferential groove;
A rotary anode X-ray tube comprising:     One end of the fixed shaft is fixed, and the rotating body is formed in a bottomed cylindrical shape. A seal portion for preventing leakage of the lubricant is provided between the rotating body and the fixed shaft. 6. The rotating anode X-ray tube according to claim 5, wherein the rotating anode X-ray tube is provided.     The fixed shaft is fixed at both ends, and the rotating body is formed in a cylindrical shape having both ends open. A seal portion for preventing leakage of the lubricant is fixed to the fixed shaft at both openings of the rotating body. 6. The rotary anode X-ray tube according to claim 5, wherein     The end of the rotating body is provided with a thin structure at the end of the rotating body at the end of the rotating body at the end of the rotating body by a notched circumferential groove and a cylindrical flange on the outer periphery of the circumferential groove. The rotary anode X-ray tube according to Item 6 or Claim 7.     6. The rotary anode type X-ray tube according to claim 5, wherein a liquid supply hole through which the lubricant passes is provided in the flange portion.     6. The thin-walled structure is provided on the storage unit side, and a liquid supply hole through which the lubricant passes is provided in the flange portion extending to the storage unit. A rotating anode X-ray tube as described in 1. above.     The liquid supply hole through which the lubricant passes is provided through the flange, and the liquid supply hole is opened in a bearing groove of the dynamic pressure bearing. Item 6. The rotating anode X-ray tube according to Item 5.     The liquid supply hole is provided with a liquid supply hole through which the lubricant passes through a flange portion in a direction in which a centrifugal force applied to the X-ray tube is applied as the X-ray tube rotates. The rotary anode type X-ray tube according to claim 1 or 5, wherein

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