JP6180870B2 - Rotating anode X-ray tube - Google Patents

Description

  Embodiments described herein relate generally to a rotary anode X-ray tube.

  In general, a rotary anode type X-ray tube device is used as the X-ray tube device. The rotary anode type X-ray tube device includes a rotary anode type X-ray tube that emits X-rays, a stator coil, and a housing that houses the rotary anode type X-ray tube and the stator coil. The rotating anode type X-ray tube includes a rotating body having an anode target, a fixed shaft that rotatably supports the rotating body, a cathode, and a vacuum envelope. The fixed shaft is supported by a support member. The fixed shaft and the support member are coupled by, for example, normal screw fastening. The support member is fixed to the vacuum envelope or the housing.

  Rotating anode X-ray tubes are used in various medical devices. Among these, when a rotating anode X-ray tube is used in an X-ray CT (computer tomography) apparatus, it is large in the direction perpendicular to the central axis of the fixed axis due to the centrifugal force caused by the rotation of the CT mount. Force acts. For this reason, a very large bending moment acts on the contact surface between the fixed shaft and the support member. In particular, as the performance of the CT mount increases, the bending moment that cannot be maintained with normal screw fastening when the rotational speed of the CT mount is increased or the heat capacity of the anode target is increased by increasing the weight of the rotating body. Acts on the contact surface.

  As a result, a deviation occurs on the contact surface, and the assembly of the fixed shaft and the rotating body is rattled, resulting in greatly impairing the performance of the rotating anode X-ray tube. In view of this, there has been proposed a technique aimed at obtaining a stable rotating operation of the rotating body.

JP 2005-78918 A JP 2004-171868 A

  For example, Patent Document 2 discloses a technique aimed at obtaining a stable rotational operation of the rotating body. However, the centrifugal force due to the rotation of the CT mount acts on the fixed shaft and the assembly of the rotating bodies many times. Then, even if a rotary anode type X-ray tube is formed as in Patent Document 2, contact surfaces (a contact surface between the fixed shaft 18 and the support mechanism 26 and a contact surface between the support mechanism 26 and the nut 19) are formed. There is a risk that the play will gradually increase, and the displacement of the fixed shaft may also increase gradually. When the displacement of the fixed shaft is increased, the vibration generated in the rotary anode X-ray tube is increased. As described above, even if the rotary anode X-ray tube adopts a double-sided bearing structure, it is difficult to keep the fixed shaft fixed.

Therefore, there is a need for a technique that can stabilize the rotating operation of the rotating body and prevent an increase in vibration generated in the rotary anode X-ray tube, that is, a technique that can maintain the fixed shaft in a fixed state. It has been.
The present invention has been made in view of the above points, and an object thereof is to provide a rotary anode type X-ray tube capable of maintaining a fixed shaft in a fixed state.

A rotary anode X-ray tube according to an embodiment is:
A first shaft portion formed in a columnar shape, a second shaft portion formed in a columnar shape with one end positioned on the first shaft portion side and formed at the other end, and a columnar shape A first joint surface formed on the outer peripheral surface of the second shaft portion, the first joint surface being formed on the other end side of the second shaft portion and having an outer diameter smaller than the outer diameter of the second shaft portion; A fixed shaft having a third shaft portion coaxially and integrally formed with the first shaft portion and the second shaft portion, wherein the first joint surface is located on one end side of the third shaft portion. The first screw portion is located on the other end side of the third shaft portion, and the first contact surface is located on the outer side of the third shaft portion;
A rotating body that has an anode target that emits X-rays when electrons collide, and is rotatably supported by a bearing around the first shaft portion;
A hardness lower than the hardness of the fixed shaft, a through-hole extending along the central axis of the fixed shaft, a protrusion formed at one end along the central axis, and along the central axis A second contact surface formed on the other end, and is a support member that supports the fixed shaft by being fitted to the third shaft portion with a gap through the through hole, and the protrusion is The support member abutted against the first contact surface;
A second screw portion that is screwed to the first screw portion of the third shaft portion, and a third contact surface; and a fastener that generates a force to compress the support member,
By generating a force to compress the support member,
The protruding portion causes plastic deformation, and forms a fourth contact surface pressed against the first contact surface, and a second joint surface having a shape matching the first joint surface,
The support member is caulked to the fixed shaft;
The third contact surface is in pressure contact with the second contact surface.

FIG. 1 is a cross-sectional view showing a rotary anode X-ray tube according to an embodiment. FIG. 2 is an enlarged cross-sectional view showing a part of the rotary anode X-ray tube shown in FIG.

  Hereinafter, a rotary anode X-ray tube according to an embodiment will be described in detail with reference to the drawings. Although not shown, the rotary anode X-ray tube includes a stator coil as a coil for generating a magnetic field, a casing containing the rotary anode X-ray tube and the stator coil, and a casing and the rotary anode X-ray tube. A rotary anode X-ray tube device can be formed together with the coolant filled in the space between them. The rotary anode type X-ray tube apparatus can be used for an X-ray CT (computerized tomography) apparatus.

  As shown in FIG. 1, the rotary anode X-ray tube 1 includes an anode target 50, a cathode 60, a vacuum envelope 70, a support member 80, and a fastener 90. Further, the rotary anode X-ray tube 1 includes a fixed shaft 10, a rotating body 20, and a liquid metal LM as a lubricant, and uses a sliding bearing. The rotating anode type X-ray tube 1 may use a rolling bearing instead of the sliding bearing.

  Here, assuming that a very high centrifugal load (high load) is applied to the rotary anode X-ray tube 1, the vacuum envelope 70 is formed of a strong metal member. For this reason, the design which completely fixes the fixed axis | shaft 10 to the vacuum envelope 70 is attained. The vacuum envelope 70 is firmly supported by the housing and has a structure that can sufficiently withstand a very high centrifugal load.

  As shown in FIGS. 1 and 2, the fixed shaft 10 has a first shaft portion 11, a second shaft portion 12, and a third shaft portion 13. The first shaft portion 11, the second shaft portion 12, and the third shaft portion 13 are coaxially and integrally formed. The fixed shaft 10 is a solid member and is made of a metal having high hardness such as carbon steel. As the carbon steel, for example, a material having high hardness and strength described as SKD11 in the JIS standard can be used. The fixed shaft 10 may be formed of a material other than carbon steel, for example, molybdenum or a molybdenum alloy.

  The 1st axial part 11 is formed in the column shape. In this embodiment, the first shaft portion 11 includes a first radial bearing surface formed on the outer peripheral surface, a first thrust bearing surface formed on one end, a second thrust bearing surface formed on the other end, have. In the direction along the central axis a of the fixed shaft 10, the outer diameter of the first shaft portion 11 is uniform.

  The second shaft portion 12 is formed in a cylindrical shape. One end of the second shaft portion 12 is located on the other end side of the first shaft portion 11. The second shaft portion 12 has a first contact surface 12s formed at the other end. The first contact surface 12 s is located outside the third shaft portion 13. In this embodiment, the outer diameter of the second shaft portion 12 is uniform in the direction along the central axis a. The outer diameter of the second shaft portion 12 is smaller than the outer diameter of the first shaft portion 11.

  The third shaft portion 13 is formed in a cylindrical shape. The third shaft portion 13 has an outer diameter smaller than the outer diameter of the second shaft portion 12. One end of the third shaft portion 13 is located on the other end side of the second shaft portion 12. When the third shaft portion 13 is regarded as a screw shaft, the third shaft portion 13 includes a so-called cylindrical portion 14 (a portion where no screw is engraved on the outer peripheral surface) and a so-called screw portion having a screw tip (on the outer peripheral surface). And a first screw portion 15 as a portion in which a screw is engraved. The third shaft portion 13 (cylindrical portion 14) has a first joint surface 14s formed on the outer peripheral surface. For this reason, the first joint surface 14 s is located on one end side of the third shaft portion 13, and the first screw portion 15 is located on the other end side of the third shaft portion 13. In this embodiment, the first screw portion 15 is a male screw.

In this embodiment, a part of the outer peripheral surface of the third shaft portion 13 including the first joint surface 14s is a tapered surface. Here, the outer peripheral surface of the cylindrical portion 14 is entirely a tapered surface. The third shaft portion 13 (cylindrical portion 14) is formed so that the outer diameter of one end of the third shaft portion 13 is the largest among the outer diameters of the third shaft portion 13.
In addition, the 3rd axial part 13 (cylindrical part 14) does not need to have a taper surface. In this case, the outer diameter of the cylindrical portion 14 may be uniform in the direction along the central axis a.

  As shown in FIG. 1, the rotating body 20 is rotatably supported by a sliding bearing (bearing) around the first shaft portion 11 (fixed shaft 10). The rotating body 20 includes a rotating unit 30, a connecting unit 40, and an anode target 50.

  The rotating portion 30 is formed in a cylindrical shape having one end closed and the other end recessed in a circular frame shape, and is provided coaxially with the fixed shaft 10. The rotating part 30 extends in a direction along the central axis a. Specifically, the rotating unit 30 is formed of a cylindrical main body 31 with one end closed, and a lid 32 detachably screwed to the other end of the main body 31. The rotating part 30 is made of metal such as Fe alloy or Mo alloy. The fixed shaft 10 is fitted inside the rotating unit 30 with a gap. The rotating unit 30 can rotate around the fixed shaft 10.

  The main body 31 includes a second radial bearing surface that faces the first radial bearing surface of the first shaft portion 11 with a gap and a third thrust that faces the first thrust bearing surface of the first shaft portion 11 with a gap. And a bearing surface. The lid portion 32 has a fourth thrust bearing surface opposed to the second thrust bearing surface of the first shaft portion 11 with a gap.

  The fixed shaft 10 and the rotating unit 30 are provided with a gap therebetween in the entire facing region. The gap between the bearing surfaces is, for example, about 20 μm. The first shaft portion 11 is covered with the rotating portion 30. The second shaft portion 12 protrudes outside the rotating portion 30. The fixed shaft 10 supports the rotating body 20 in a rotatable manner.

  The anode target 50 includes an anode body 51 and a target layer 52 provided on a part of the outer surface of the anode body 51. The anode target 50 can rotate together with the rotating body 20. The anode target 50 emits X-rays when electrons collide with the target layer 52.

  In this embodiment, the anode target 50 is formed in an annular shape and is provided coaxially with the fixed shaft 10 and the rotating unit 30. The anode target 50 is fixed to one end of the rotating unit 30 via the connection unit 40.

  The liquid metal LM is filled in a gap between the fixed shaft 10 and the rotating unit 30. Specifically, the liquid metal LM is filled in a gap between the first shaft portion 11 and the rotating portion 30. As the liquid metal LM, a material such as a GaIn (gallium / indium) alloy or a GaInSn (gallium / indium / tin) alloy can be used.

  The liquid metal LM forms a radial slide bearing B1 together with the first radial bearing surface of the first shaft portion 11 and the second radial bearing surface of the rotating portion 30. The liquid metal LM forms a first thrust sliding bearing B2 together with the first thrust bearing surface of the first shaft portion 11 and the third thrust bearing surface of the rotating portion 30. The liquid metal LM forms a second thrust slide bearing B3 together with the second thrust bearing surface of the first shaft portion 11 and the fourth thrust bearing surface of the rotating portion 30.

  As shown in FIGS. 1 and 2, the support member 80 supports the fixed shaft 10. The support member 80 is a solid member and has a hardness lower than that of the fixed shaft 10. As a material for forming the support member 80, for example, a material described as SUS304 in the JIS standard can be used. Further, the support member 80 may be made of a material other than SUS304, such as Kovar, and the support member 80 has a lower hardness than the fixed shaft 10 so that the support member 80 can cause plastic deformation. It only has to be formed.

  The support member 80 has a through hole 80h, a protrusion 80p, and a second contact surface 80s1. The through hole 80h extends along the central axis a. In this embodiment, the through hole 80 h has a shape corresponding to the outer peripheral surface of the cylindrical portion 14. The outline of the through hole 80h is circular. The support member 80 is formed in an annular shape. The protrusion 80 p is formed at one end along the central axis a of the support member 80. The second contact surface 80s1 is formed at one other end (the other end) along the central axis a of the support member 80.

  The support member 80 is fitted to the third shaft portion 13 (cylindrical portion 14) with a gap through the through hole 80h. The fitting gap between the cylindrical portion 14 and the support member 80 employs a very small dimension of 10 μm or less in diameter. Of the fitting gap between the third shaft portion 13 (cylindrical portion 14) and the support member 80, the gap between the first joint surface 14s and the protruding portion 80p is set to be the smallest.

  The protrusion 80p is formed in an annular shape. In the direction along the central axis a, the inner diameter of the protrusion 80p (support member 80) is the same. The outer peripheral surface of the protrusion 80p is a tapered surface. Of the outer diameters of the protrusions 80p, the outer diameter of one end of the protrusion 80p near the first contact surface 12s is the smallest. The protrusion 80p is abutted against the first contact surface 12s. The second contact surface 80s1 is parallel to the first contact surface 12s.

  The fastener 90 generates a force that compresses the support member 80. The fastener 90 has a second screw portion 91h1 and a third contact surface 92s. The second screw portion 91 h 1 is screwed into the first screw portion 15 of the third shaft portion 13. In this embodiment, the 2nd screw part 91h1 is a screw hole, and is an internal thread.

Here, the phenomenon which arises when the force which compresses the support member 80 with the fastener 90 is generated is demonstrated.
(1) The protrusion 80p causes plastic deformation, and forms a fourth contact surface 80s2 that is press-contacted with the first contact surface 12s, and a second joint surface 80s3 having a shape that matches the first joint surface 14s. As a result, the support member 80 is caulked to the fixed shaft 10.

  That is, the protrusion 80p is slightly shortened in the direction along the central axis a in the vicinity of the first joint surface 14s. The protrusion 80p has a slightly smaller diameter (inner diameter) in the vicinity of the first bonding surface 14s. Since the gap between the first joint surface 14 s and the second joint surface 80 s 3 is completely eliminated due to plastic deformation of the protrusion 80 p (support member 80), the support member 80 is very strongly clamped to the fixed shaft 10. Accordingly, the support member 80 can completely restrain the fixed shaft 10 in the vicinity of the first joint surface 14s. Note that the fixed shaft 10 is formed using a material having high hardness such as SKD11 and has a hardness higher than the hardness of the support member 80, so that the fixed shaft 10 itself is not plastically deformed.

  (2) The third contact surface 92s is in pressure contact with the second contact surface 80s1.

  From the events (1) and (2) above, (i) the contact surface between the first contact surface 12s and the fourth contact surface 80s2, and (ii) the contact surface between the second contact surface 80s1 and the third contact surface 92s. These two points function as support points, and the support member 80 is fixed to the fixed shaft 10, so that the support member 80 maintains the fixed shaft 10 in a fixed state.

  As described above, the fastener 90 needs to generate a sufficient fastening axial force in order to deform the protrusion 80p. Therefore, in the present embodiment, the rotary anode X-ray tube 1 uses Super Bolt (registered trademark).

  Specifically, the fastener 90 includes a nut 91, a washer (flat washer) 92, and a plurality of jack bolts 93. The nut 91 has the second screw portion 91h1 and a plurality of screw holes 91h2 positioned around the second screw portion 91h1. The plurality of screw holes 91h2 are provided at equal intervals around the second screw portion 91h1.

  The jack bolt 93 is screwed into the screw hole 91h2. In this embodiment, the jack bolt 93 is a hexagon bolt. The head of the jack bolt 93 is located between the support member 80 and the nut 91. The jack bolt 93 is provided with various grooves and holes depending on the use for driving the inside so as to open at the screw tip. For example, the jack bolt 93 is provided with a hexagonal hole so as to open at the screw tip. The jack bolt 93 can be turned by using a hex driver, a hex wrench or the like. In addition, when big torque is required, it can respond, for example by using a hexagon stick spanner.

  The washer 92 is sandwiched between the plurality of jack bolts 93 and the support member 80. In this embodiment, the washer 92 has the third contact surface 92s.

  The resultant force generated by the plurality of jack bolts 93 acts as an axial force on the fixed shaft 10 via the nut 91 and acts as a tightening force on the support member 80 via the washer 92. For this reason, the plurality of jack bolts 93 generate a force for compressing the support member 80 together with the nut 91.

  In this embodiment, the total area where the second contact surface 80s1 and the third contact surface 92s are in pressure contact is smaller than the total area where the first contact surface 12s and the fourth contact surface 80s2 are in pressure contact.

  The cathode 60 is disposed to face the target layer 52 of the anode target 50 with a space therebetween. The cathode 60 is attached to the inner wall of the vacuum envelope 70. The cathode 60 has a filament 61 as an electron emission source that emits electrons irradiated to the target layer 52.

  The vacuum envelope 70 has an envelope body 71 and a sealing member 72. The envelope body 71 is formed in a cylindrical shape and has an opening. The envelope body 71 is made of metal. In the envelope body 71, the diameter of the part facing the anode target 50 is larger than the diameter of the part facing the rotating part 30. The opening of the envelope body 71 is hermetically closed by the sealing member 72, and the inside of the vacuum envelope 70 is maintained in a vacuum state. The vacuum envelope 70 accommodates the fixed shaft 10, the rotating body 20, the anode target 50, the cathode 60, the support member 80, the fastener 90, and the like.

The support member 80 is fixed to the vacuum envelope 70. The support member 80 is fixed to the vacuum envelope 70 by generally known fixing means such as brazing or welding. In this embodiment, the rotary anode X-ray tube 1 employs a one-end support bearing structure. The vacuum envelope 70 fixes the support member 80 and indirectly fixes the third shaft portion 13. That is, it functions as a cantilever support portion of the third shaft portion 13 bearing.
As described above, the rotary anode X-ray tube 1 used for the X-ray tube apparatus is formed.

  In the operating state of the X-ray tube apparatus, the stator coil described above generates a magnetic field to be applied to the rotating unit 30, and therefore the rotating body 20 (the anode target 50 and the like) rotates. In addition, a relatively negative voltage is applied to the cathode 60 and a relatively positive voltage is applied to the anode target 50.

  Thereby, a potential difference is generated between the cathode 60 and the anode target 50. For this reason, when the filament 61 emits electrons, the electrons are accelerated and collide with the target layer 52. Thereby, the target layer 52 emits X-rays when colliding with electrons, and the emitted X-rays pass through the vacuum envelope 70. The X-rays are further transmitted through the X-ray transmission window of the casing described above and emitted to the outside of the casing.

  According to the rotary anode X-ray tube 1 according to the first embodiment configured as described above, the rotary anode X-ray tube 1 includes the fixed shaft 10 and the rotating body 20 having the anode target 50. A support member 80 that supports the fixed shaft 10 and a fastener 90 are provided. The support member 80 has a hardness lower than that of the fixed shaft 10. The fastener 90 includes a second screw portion 91 h 1 that is screwed into the first screw portion 15, and generates a force that compresses the support member 80.

  As a result, the projecting portion 80p undergoes plastic deformation to form a fourth contact surface 80s2 pressed against the first contact surface 12s and a second joint surface 80s3 having a shape matching the first joint surface 14s. The support member 80 is caulked to the fixed shaft 10. The third contact surface 92s is in pressure contact with the second contact surface 80s1. The two points of (i) the contact surface of the first contact surface 12s and the fourth contact surface 80s2 and (ii) the contact surface of the second contact surface 80s1 and the third contact surface 92s function as support points. Since the support member 80 is caulked to the fixed shaft 10, the support member 80 can maintain the fixed shaft 10 in a fixed state.

  For this reason, even if the centrifugal force due to the rotation of the CT mount acts on the assembly of the fixed shaft 10 and the rotating body 20 many times, the support member 80 is caulked to the fixed shaft 10, so the contact (i) above It is possible to prevent a situation where play occurs between the surface and the contact surface (ii) (a situation where rattling occurs between the fixed shaft 10 and the support member 80). Further, it is possible to prevent a situation where the play gradually increases, that is, it is possible to prevent a situation where the displacement of the fixed shaft 10 gradually increases. Thereby, the rotation operation of the rotating body 20 can be stabilized, and an increase in vibration generated in the rotary anode X-ray tube 1 can be prevented.

  Further, not only the nut 91 but also the aggregate of the nut 91 and the plurality of jack bolts 93 can generate a force for compressing the support member 80. For this reason, the size of the nut 91 (fastener 90) is increased as compared with the case where the force for compressing the support member 80 is generated only by the nut 91 (when the fastener 90 is formed without the plurality of jack bolts 93). It is possible to use a small-sized nut 91 that can prevent the above-described problem.

  A part of the outer peripheral surface of the third shaft portion 13 including the first joint surface 14s is a tapered surface. In this embodiment, the outer peripheral surface of the cylindrical portion 14 is entirely a tapered surface. The third shaft portion 13 (cylindrical portion 14) is formed so that the outer diameter of one end of the third shaft portion 13 is the largest among the outer diameters of the third shaft portion 13. For this reason, the effect that the fixed shaft 10 and the support member 80 can be smoothly fitted can be further obtained.

  Of the fitting gap between the third shaft portion 13 (cylindrical portion 14) and the support member 80, the gap between the first joint surface 14s and the protruding portion 80p is set to be the smallest. For this reason, the support member 80 can be fixed to the fixed shaft 10 by slightly plastically deforming the protrusion 80p.

  The total area where the second contact surface 80s1 and the third contact surface 92s are pressure-contacted is smaller than the total area where the first contact surface 12s and the fourth contact surface 80s2 are pressure-contacted. For this reason, it is possible to satisfactorily plastically deform the protruding portion 80p of the support member 80, not the second contact surface 80s1 side.

Further, the second contact surface 80s1 is parallel to the first contact surface 12s. For this reason, the protrusion 80p can be efficiently plastically deformed.
As described above, the rotary anode X-ray tube 1 that can maintain the fixed shaft 10 in a fixed state can be obtained.

  Although one embodiment of the present invention has been described, the above embodiment has been presented as an example, and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, the fastener 90 may be provided with a washer 92 as necessary. When the fastener 90 is formed without the washer 92, the plurality of jack bolts 93 each have the third contact surface instead of the washer 92. Also in this case, the total contact area between the second contact surface 80s1 and the third contact surface (the contact surface of the head of the jack bolt 93) is the first contact surface 12s and the fourth contact surface 80s2. Smaller than the total area is desirable.

  Further, the rotary anode X-ray tube 1 may not use a super bolt. Although there is a risk of increasing the size of the nut 91 (fastener 90), the same effects as those of the above-described embodiment can be obtained.

  For example, the fastener 90 may include a nut having a second screw portion 91h1 and a third contact surface pressed against the second contact surface 80s1. Alternatively, the fastener 90 includes a nut having a second screw portion 91h1, and a washer 92 having a third contact surface 92s that is sandwiched between the nut and the support member 80 and pressed against the second contact surface 80s1. , May be provided.

  In the above embodiment, the case where the rotary anode X-ray tube 1 employs a single-end support bearing structure has been described as an example. However, the present invention is not limited to this, and the rotary anode X-ray tube 1 has a double-end support bearing structure. Even if it is adopted, the embodiment of the present invention can be applied, and the same effect as the above-described embodiment can be obtained.

Various holes or holes may be formed inside the fixed shaft 10. For example, a cooling hole through which the coolant flows or a through-hole cooling hole may be formed inside the fixed shaft 10.
Further, the fixed shaft 10 may have a shelter or a reservoir of the liquid metal LM inside. The shelter and the reservoir only need to communicate with the outer peripheral surface of the fixed shaft 10.

  In the embodiment described above, the case where the support member 80 is fixed to the vacuum envelope 70 has been described. However, the present invention is not limited to this, and various modifications can be made. For example, when the fixed shaft 10 is located outside the vacuum envelope 70, the support member 80 may be fixed to the housing.

  DESCRIPTION OF SYMBOLS 1 ... Rotary anode type | mold X-ray tube, 10 ... Fixed axis | shaft, 11 ... 1st axial part, 12 ... 2nd axial part, 12s ... 1st contact surface, 13 ... 3rd axial part, 14 ... Cylindrical part, 14s ... 1st DESCRIPTION OF SYMBOLS 1 Joining surface, 15 ... 1st thread part, 20 ... Rotating body, 30 ... Rotating part, 50 ... Anode target, 60 ... Cathode, 70 ... Vacuum envelope, 80 ... Support member, 80h ... Through-hole, 80p ... Projection 80s1 ... second contact surface, 80s2 ... fourth contact surface, 80s3 ... second joint surface, 90 ... fastener, 91 ... nut, 91h1 ... second screw portion, 91h2 ... screw hole, 92s ... third contact surface , 92 ... washer, 93 ... jack bolt, a ... central axis.

Claims (8)

A first shaft portion formed in a columnar shape, a second shaft portion formed in a columnar shape with one end positioned on the first shaft portion side and formed at the other end, and a columnar shape A first joint surface formed on the outer peripheral surface of the second shaft portion, the first joint surface being formed on the other end side of the second shaft portion and having an outer diameter smaller than the outer diameter of the second shaft portion; A fixed shaft having a third shaft portion coaxially and integrally formed with the first shaft portion and the second shaft portion, wherein the first joint surface is located on one end side of the third shaft portion. The first screw portion is located on the other end side of the third shaft portion, and the first contact surface is located on the outer side of the third shaft portion;
A rotating body that has an anode target that emits X-rays when electrons collide, and is rotatably supported by a bearing around the first shaft portion;
A hardness lower than the hardness of the fixed shaft, a through-hole extending along the central axis of the fixed shaft, a protrusion formed at one end along the central axis, and along the central axis A second contact surface formed on the other end, and is a support member that supports the fixed shaft by being fitted to the third shaft portion with a gap through the through hole, and the protrusion is The support member abutted against the first contact surface;
A second screw portion that is screwed to the first screw portion of the third shaft portion, and a third contact surface; and a fastener that generates a force to compress the support member,
By generating a force to compress the support member,
The protruding portion causes plastic deformation, and forms a fourth contact surface pressed against the first contact surface, and a second joint surface having a shape matching the first joint surface,
The support member is caulked to the fixed shaft;
The third contact surface is a rotary anode X-ray tube that is pressed against the second contact surface. Of the outer peripheral surface of the third shaft portion, a part including the first joint surface is a tapered surface,
2. The rotary anode X-ray tube according to claim 1, wherein the outer diameter of one end of the third shaft portion is the largest among the outer diameters of the third shaft portion.   2. The rotary anode X-ray tube according to claim 1, wherein a gap between the first joint surface and the protrusion is set to be the smallest among fitting gaps between the fixed shaft and the support member. . The fastener includes a nut having the second screw portion and a plurality of screw holes positioned around the second screw portion, and a plurality of jack bolts screwed into the plurality of screw holes. ,
2. The rotary anode X-ray tube according to claim 1, wherein each of the plurality of jack bolts has the third contact surface and generates a force for compressing the support member together with the nut. The fastener includes a nut having the second screw portion and a plurality of screw holes positioned around the second screw portion, a plurality of jack bolts screwed into the plurality of screw holes, and the plurality A washer sandwiched between the jack bolt and the support member,
The washer has the third contact surface;
The rotary anode X-ray tube according to claim 1, wherein the plurality of jack bolts generate a force for compressing the support member together with the nut.   2. The rotary anode type X according to claim 1, wherein a total area where the second contact surface and the third contact surface are press-contacted is smaller than a total area where the first contact surface and the fourth contact surface are press-contacted. Wire tube.   2. The rotary anode X-ray tube according to claim 1, wherein the fastener includes a nut having the second screw portion and the third contact surface.   2. The rotation according to claim 1, wherein the fastener includes a nut having the second threaded portion, and a washer sandwiched between the nut and the support member and having the third contact surface. Anode X-ray tube.

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