JP2010044897A - X-ray tube device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray tube device that can efficiently reduce oscillation generated from a rotating anode. <P>SOLUTION: By making a vibration-proof member 10b attenuating oscillation generated at rotation of the rotating anode intervene between a rotating anode support means 10 supporting the rotating anode 4f and an X-ray tube-mounting means 14, oscillation, if any, generated due to manufacturing accuracy or assembling accuracy of a rotating anode, a rotating anode support means or the like is absorbed and attenuated by the vibration-proof member, so that oscillation transmitted further toward a housing 2 side than the X-ray tube mounting means and ensuing noise can be greatly reduced, and moreover, since oscillation generated from the rotating anode is suppressed as the rotating anode support means becomes a soft-supporting structure due to the vibration-proof member, oscillation of the rotating anode itself can also be reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an X-ray tube apparatus in which vibration generated from a rotating anode is reduced.

Conventionally, a medical X-ray apparatus for diagnosing a subject using X-rays and an industrial X-ray inspection apparatus for inspecting a subject such as an article with X-rays usually have an X-ray tube apparatus as an X-ray generation source. Is used.
In this X-ray tube apparatus, an X-ray tube is accommodated in a housing filled with insulating oil.
An X-ray tube is composed of an anode disposed opposite to a cathode that emits thermoelectrons in a vacuum vessel. When a high voltage is applied between the cathode and the anode, the thermoelectrons are accelerated toward the anode. An X-ray tube current flows between the electrodes.
The thermoelectrons reaching the anode form an electron beam spot on the target surface provided on the anode, and X-rays are generated from the electron beam spot.
X-rays generated from the electron beam spot of the target are irradiated toward the subject from an X-ray irradiation port provided on the outer peripheral surface of the housing and used for examination of the subject. The conversion rate of X-rays is slight, and the remaining electric power becomes heat to heat the anode target and its surroundings.

When heat is concentrated in the target electron beam spot, the target electron beam spot may be melted by the heat. Therefore, the target electron is dispersed by rotating the anode to disperse the electron beam spot on the target surface. An X-ray tube apparatus using a rotary anode type X-ray tube that prevents heat from being concentrated in a line spot has been put into practical use.
In a conventional X-ray tube apparatus that employs a rotating anode type X-ray tube, the rotating rotating anode is supported by a vacuum vessel through a bearing such as a ball bearing. Vibration may occur when the rotating anode rotates due to the gaps or the like.
When the rotating anode vibrates, the vibration is propagated to the vacuum vessel via the supporting means for supporting the rotating anode, and further propagated to the housing via the X-ray tube attaching means. There are problems that reduce the resolution of line images and cause noise.

In order to improve such a problem, for example, Patent Document 1 proposes a rotary anode X-ray tube device in which a vacuum vessel is formed of a stainless steel foam metal having a Claude cell structure.
In the rotary anode X-ray tube device described in Patent Document 1, the vibration generated in the rotary anode is transmitted to the X-ray holding device by utilizing the vibration-proof and sound-proof characteristics of the stainless foam metal having a Claude cell structure. At the same time, noise leakage from the vacuum vessel is reduced.
JP 2007-179936 A

However, in the rotary anode X-ray apparatus described in Patent Document 1, there is a problem that the cost is increased because the vacuum vessel must be manufactured from a stainless steel foam metal having a Claude cell structure.
Also, the vibration generated in the rotating anode is propagated to the vacuum vessel through the supporting means for supporting the rotating anode and absorbed by the vacuum vessel, so that the vibration to the supporting means such as the bearing supporting the rotating anode is reduced. As a result, there is a problem that the bearing for supporting the rotating anode wears out early and the durability of the X-ray tube is lowered or the noise increases with time.
The present invention has been made to remedy such a problem, and an object of the present invention is to provide an X-ray tube apparatus capable of efficiently reducing vibration generated from a rotating anode.

  The X-ray tube apparatus according to the present invention fills a rotating anode type X-ray tube that generates X-rays from a target provided on the rotating anode by applying a high voltage between the cathode and the rotating anode. An X-ray tube apparatus which is housed in a sealed housing and has an X-ray tube mounted in the housing via an X-ray tube mounting unit, the rotating anode supporting means for supporting the rotating anode, and the X-ray An anti-vibration member for reducing vibration generated when the rotating anode rotates is interposed between the tube attaching means.

  In the X-ray tube device of the present invention, the vibration-proof member is formed of an elastic material that swells and softens when immersed in insulating oil.

  In the X-ray tube apparatus of the present invention, the vibration isolating members are attached to both surfaces of the anode supporting member forming the rotating anode supporting means, and the anode supporting member is attached to the X-ray tube attaching means in a compressed state. At the same time, the vibration isolating member is immersed in the insulating oil filled in the housing to swell and soften the vibration isolating member.

  In the X-ray tube device of the present invention, the vibration isolating member is formed by molding a three-component silicon made of the three components of the main agent, the crosslinking agent and the adhesion promoter into a predetermined shape.

  According to the X-ray tube apparatus of the present invention, it is possible to provide an X-ray tube apparatus that can efficiently reduce vibrations generated from the rotating anode.

Embodiments of the present invention will be described in detail with reference to the drawings.
1 is a cross-sectional view of the X-ray tube device, FIG. 2 is an enlarged cross-sectional view in the vicinity of the rotary anode, FIG. 3 is an enlarged side view of the rotary anode support means, FIG. 4 is a view from the direction of arrow A in FIG. FIG. 4 is a diagram showing the relationship between vibration acceleration and frequency.
FIG. 1 shows a main body 1 of an X-ray tube apparatus used for, for example, a medical X-ray apparatus or an industrial X-ray inspection apparatus, and has a sealed structure housing 2 formed of metal.
The X-ray tube 4 is accommodated in the housing 2 so that the X-ray irradiation direction (arrow B) is directed to the X-ray irradiation port 2 a formed on the outer peripheral surface of the housing 2. One end side is fixed to a flange 2b protruding from the inner peripheral surface of the housing 2 by an X-ray tube mounting means 14 described later.

The X-ray tube 4 has a vacuum vessel 4a provided so that the central axis thereof coincides with the central axis of the housing 2, and the vacuum vessel 4a is formed with a large diameter at one end and a small diameter at the other end. The inside of the housing 2 is in a vacuum state, and the housing 2 is filled with insulating oil 3 for cooling the X-ray tube 4.
A cathode holding member 4d for holding the cathode 4e is provided in the end on the large diameter portion 4b side of the vacuum vessel 4a, and the cathode 4e is attached to the cathode holding member 4d so as to be eccentric with respect to the center of the vacuum vessel 4a. The rotating anode 4f is provided at a position facing the cathode 4e.
The rotating anode 4f is formed in a disk shape as shown in FIG. 2, and the surface facing the cathode 4e is inclined at a predetermined angle with respect to the X-ray irradiation direction B, and the inclined surface 4g has a disk shape. Target 4h is provided.

The central portion of the rotating anode 4f is fixed to a rotating shaft 5c protruding from one end of the rotor 5a constituting the rotation driving means 5 by a fixing means 5d such as a nut.
The rotation driving means 5 rotates the rotary anode 4f at high speed, and includes a cylindrical rotor 5a and a stator 5b provided on the outer periphery of the vacuum vessel 4a on the small diameter portion 4c side.
As shown in FIG. 2, the rotor 5a is formed in a cylindrical shape with one end side closed by an end plate 5e and the other end side opened, and a rotating anode 5 is provided on a rotating shaft 5c protruding from the center of the end plate 5e. The central portion of 4f is fixed, and the rotating anode 4f is rotated integrally with the rotor 5a.

A support shaft 5f is provided at the center of the rotor 5a concentrically with the rotation center of the rotary anode 4f.
One end side of the support shaft 5f is a hollow shaft 5g inserted into the rotor 5a from the other end side opening of the rotor 5a, and the other end side is a solid shaft 5h protruding outside the rotor 5a. The magnet body 5i is provided on the outer peripheral surface of the hollow shaft 5g over the entire circumference.
A rotor shaft 5j is provided at the center of the hollow shaft 5g, and one end side of the rotor shaft 5j protruding from the opening on one end side of the hollow shaft 5g toward the rotating shaft 5c is fixed to the inner peripheral surface of the rotor 5a. Thus, the rotor shaft 5j and the rotor 5a are rotated together.
A pair of bearings 6 is provided between the rotor shaft 5j and the hollow shaft 5g with a gap in the axial direction of the rotor shaft 5j, and the bearing is also provided between one end of the rotor 5a and one end of the hollow shaft 5g. 7, the rotor 5a is rotatably supported by the support shaft 5f by these bearings 6 and 7, and a compression spring 8 is interposed between the other end side of the rotor shaft 5j and the solid shaft 5h. Has been.

The solid shaft 5h provided on the other end side of the hollow shaft 5g is screwed into a boss portion 10e provided on the center portion of the anode support member 10a constituting the rotary anode support means 10 on the other end side.
The rotary anode support means 10 includes an anode support member 10a that supports the other end of the support shaft 5f, and a vibration isolation member 10b that absorbs and attenuates vibrations generated by the rotation of the rotary anode 4f and the rotor 5a of the rotation drive means 5. Become.
As shown in FIGS. 3 and 4, the anode support member 10 a is provided on both surfaces of the support plate 10 c so as to surround the disc-shaped support plate 10 c and the mounting hole 10 d formed in the center of the support plate 10 c. And a cylindrical boss 10e.
The other end of the solid shaft 5h is screwed to the boss portion 10e protruding from the support plate 10c on the rotation driving means 5 side, and the boss portion 10e protruding from the opposite surface is A handle 11 in which a fixing tool 11a for fixing the shaft 5h to the boss part 10e is fitted is fitted, and the tip of the fixing tool 11a is screwed to the end of the solid shaft 5h.

On the other hand, in the support plate 10c of the anode support member 10a, as shown in FIG. 4, a plurality of, for example, six oil passage holes 10f are formed at equal intervals on the same circumference, and sandwich the center of the support plate 10c. A pair of mounting holes 10g are formed at positions facing each other.
On the same circumference on the outer peripheral side from the oil passage hole 10f, a plurality of vibration isolation members 10b are alternately provided on the front and back surfaces of the support plate 10c so as to have the same phase as the oil passage hole 10f.
The anti-vibration member 10b is made of, for example, a disk having a diameter of about 6 mm and a thickness of about 3 mm, and is manufactured using three-component silicon as follows.
Three-part silicon is prepared by mixing three parts of the main agent, a crosslinking agent and an adhesion promoter in a ratio of, for example, 50: 5: 1, and then performing a stirring and deaeration process in a vacuum of 130 Pa or less for about 30 minutes. A three-component liquid mixture is produced (all three components use a three-component RTV rubber KE1800 manufactured by Shin-Etsu Chemical Co., Ltd.).

Thereafter, a mold made of, for example, Delrin (registered trademark) resin having releasability is disposed at a position where the vibration isolating member 10b is provided on the support plate 10c.
Then, in a state where the three-liquid mixture is poured into the mold disposed on the support plate 10c, the three-liquid mixture is cured by introducing it into an atmosphere of about 100 ° C. for about 1 hour to cure the three-liquid mixture. Then, the vibration isolator 10b is formed at a predetermined position of the support plate 10c by removing the mold.
Next, the support plate 10c is immersed in an insulating oil to swell the vibration isolating member 10b formed of three-liquid silicon. The insulating oil is the same as the insulating oil 3 filled in the housing. Therefore, the swelling treatment of the vibration isolating member 10 b is performed after the X-ray tube 4 is assembled in the housing 2.

As described above, the anode support member 10a in which the vibration isolating members 10b are bonded to both surfaces of the support plate 10c is attached to the end of the stator support member 10k provided so as to cover the outer periphery of the small diameter portion of the vacuum vessel and the X-ray tube attached. It is in a state of being sandwiched between the small diameter side ends of the means 14 as shown in FIG.
And the small diameter of the X-ray tube attachment means 14 is inserted by screwing the fixing tool 15 inserted into the attachment hole of the support plate 10c from the end portion on the small diameter portion side of the X-ray tube attachment means 14 into the end portion of the stator support member 10k. At this time, the vibration isolator 10b is compressed to a thickness of about 83% before being compressed.
The stator support member 10k is formed of a cylindrical body whose end on the rotating anode 4f side is expanded in a trumpet shape, and is wound around the iron core 10n at a position facing the magnet body provided on the rotor side. The stator coil 10p is provided on the entire circumference of the stator support member 10k.
The X-ray tube mounting means 14 is formed in a tapered cylindrical shape having a large diameter on the stator 5b side and a small diameter on the anode support member 10a side, and a flange having a large diameter side protruding from the inner peripheral surface of the housing 2. 2b is fixed by an unillustrated fixing tool.

Next, the operation of the X-ray tube apparatus constructed as described above will be described.
The housing 2 of the X-ray tube apparatus assembled as shown in FIG. 1 is filled with an insulating oil 3 that cools the X-ray tube 4 from the surroundings. The insulating oil 3 is a JOMO manufactured by Japan Energy Co., Ltd. Eretas is used, and the component of the insulating oil is obtained by adding 1% of a lubricating oil additive to 99% of the lubricating base oil.
The main body 1 that has been assembled by filling the housing with the insulating oil 3 is attached to a medical X-ray apparatus or an industrial X-ray inspection apparatus (both not shown) for use. A high voltage is applied between the cathode 4d and the rotating anode 4f in a state where the rotating anode 4f is rotated at a high speed by the rotation drive source 5.
As a result, an X-ray tube current flows between the electrodes 4d and 4f, and X-rays are generated in the direction of the X-ray irradiation port 2a from the target 4h provided on the anode 4f side. Irradiated toward.

On the other hand, the insulating oil 3 filled in the housing 2 cools the periphery of the X-ray tube 4 to prevent the inside of the vacuum vessel 4a of the X-ray tube 4 from becoming high temperature, and at the same time, a part of the insulating oil 3 is The heat generated in the X-ray tube 4 and the rotary drive source 10 is cooled by entering between the small diameter portion 4b of the vacuum vessel 4a and the stator support member 10k through the oil passage hole 10f formed in the support plate 10c. The vibration isolating member 10b provided on the support plate 10c is reached and swells.
Since the temperature of the insulating oil 3 for cooling the X-ray tube 4 rises to about 100 ° C. due to the generation of X-rays by the X-ray tube 4, the vibration isolation member 10 b provided on the support plate 10 c is about 100 ° C. When it is immersed in the insulating oil 3 for 50 hours or longer in this state, swelling and softening proceed, and when immersed for a total of about 156 hours, the elastic modulus (load / deflection amount) is 6.90. To about 2.51.

As a result, when the rotating anode 4f is rotated at a high speed by the rotation driving means 5, even if the vibration is generated due to the manufacturing accuracy or assembly accuracy of the rotating anode 4f, the rotor 5a, and the rotating anode support means 10, this vibration is not generated. Since it is absorbed and attenuated by the vibration isolating member 10b when propagating to the X-ray tube mounting means 14 side via the rotating anode support means 10, vibration transmitted from the X-ray tube mounting means 14 to the housing 2 side, The noise accompanying this can be greatly reduced.
Further, by providing the vibration isolating member 10b, the rotating anode support means 10 has a soft support structure and suppresses vibrations generated from the rotating anode 4f. Since the wear of the bearings 6 and 7 that are rotatably supported can be reduced, the durability of the X-ray tube 4 is also improved.

FIG. 5 shows the relationship between vibration acceleration and frequency. Curve C shows the vibration of a conventional X-ray tube in which the rotating anode support means 10 is directly attached to the X-ray tube attachment means 14 without using the vibration isolating member 10b. The occurrence state is shown.
Curve D indicates that when the X-ray tube 4 is assembled in the housing 2, the vibration isolator 10 b is insulated with a fixing member to which the support plate 10 c is attached and the vibration isolator 10 b is tightened to a compression rate of about 2.5 / 3. The vibration isolating member 10b is swollen by immersing it in No. 3, and an anti-vibration effect is obtained by the swelling treatment, but a sufficient anti-vibration effect is not obtained for vibrations near 100 Hz.
Curve E shows that the X-ray tube 4 is assembled with the fastener 15 tightened so that the vibration isolator 10b is compressed to a thickness of about 83%, and the vibration isolator 3 is in the insulating oil 3 at about 100 ° C. for about 156 hours. It shows the anti-vibration effect in a state where 10b is immersed and swollen, and it has been confirmed that a high anti-vibration effect can be obtained in the entire frequency range.

In the above-described embodiment, the case where the X-ray tube 4 is actually operated and the vibration-proof member 10b is swollen with the insulating oil 3 filled in the housing has been described. A high voltage may be applied to the X-ray tube 4 to raise the temperature of the insulating oil 3 to about 100 ° C., and a swelling treatment with the insulating oil 3 may be performed. Since it has been experimentally found that the vibration member 10b swells and softens to an elastic modulus of about 2.52, and then converges to that value, the swelling treatment of the vibration isolation member 10b with the insulating oil 3 is performed for 50 hours or more. It is enough.
Moreover, although the said embodiment demonstrated the case where an X-ray tube apparatus was applied to industrial X-ray apparatuses, such as a medical X-ray apparatus and an X-ray inspection apparatus, it is not limited to these apparatuses. Of course.

It is sectional drawing of the X-ray tube apparatus which becomes embodiment of this invention. It is an expanded sectional view of the vicinity of the rotating anode of the X-ray tube employed in the X-ray tube apparatus according to the embodiment of the present invention. It is an expanded sectional view of the rotating anode support means of the X-ray tube employ | adopted as the X-ray tube apparatus which becomes embodiment of this invention. It is an arrow view from the A direction of FIG. It is a diagram which shows the relationship between the vibration acceleration of the X-ray tube apparatus which becomes embodiment of this invention, and a frequency.

Explanation of symbols

2 Housing 3 Insulating oil 4 X-ray tube 4f Rotating anode 4h Target 10 Rotating anode supporting means 10a Anode supporting member 10b Anti-vibration member 14 X-ray tube mounting means

Claims (4)

  A rotating anode type X-ray tube that generates X-rays from a target provided on the rotating anode by applying a high voltage between the cathode and the rotating anode is placed in a sealed housing filled with insulating oil. An X-ray tube apparatus that accommodates and mounts the X-ray tube in the housing via an X-ray tube mounting unit, the rotating anode support unit supporting the rotating anode, and the X-ray tube mounting unit An anti-vibration member for reducing vibration generated when the rotating anode rotates is interposed between the X-ray tube apparatus and the X-ray tube apparatus.   The X-ray tube apparatus according to claim 1, wherein the vibration isolating member is formed of an elastic material that swells and softens when immersed in the insulating oil.   The anti-vibration member is attached to both surfaces of the anode support member forming the rotating anode support means, and the anode support member is attached to the X-ray tube attachment means in a state where the anti-vibration member is compressed. The X-ray tube apparatus according to claim 2, wherein the vibration isolating member is immersed in the insulating oil filled in the base material to swell and soften the vibration isolating member.   The X-ray tube apparatus according to any one of claims 1 to 3, wherein the vibration isolating member is formed by molding a three-part silicon made of three parts of a main agent, a crosslinking agent, and an adhesion promoter into a predetermined shape. .

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