JP2003077412A - Rotating anode type x-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating anode type X-ray tube with reduced fluctuation of heat transferred from an anode target to a rotation body of rotary mechanism. SOLUTION: The rotating anode type X-ray tube is composed of an anode target 12 arranged within a vacuum container 11, a joint section 13 with a tubular section as its part and with the anode target combined, a rotary cylinder 17 with dynamic pressure type slide bearing at an insertion-coupling section, a fixed body 18 and of a rotary mechanism 14 supporting the rotating anode target 12 in free rotation through the joint section 13. The anode target and the joint section are combined with diffusion bonding and the rotary cylinder 17 and the joint section 13 are integrally united as one body.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rotary anode type X-ray tube.

[0002]

2. Description of the Related Art A rotary anode type X-ray tube has a structure in which an anode target is rotatably held by a rotating mechanism, and an anode target rotating at a high speed is irradiated with an electron beam so that the anode target emits X-rays. . The rotating mechanism is composed of a rotating body and a fixed body, and a bearing portion is provided between the rotating body and the fixed body. A rolling bearing such as a ball bearing or a dynamic pressure type sliding bearing is used for the bearing portion.

In a dynamic pressure type slide bearing shaft, a spiral groove is formed in a fitting portion of a rotating body and a fixed body, and a spiral groove and the like are formed.
Gallium (Ga), Ga or indium (In),
A liquid metal lubricant such as a tin (Sn) alloy is supplied. When the dynamic pressure type slide bearing is used, a large-area bearing surface filled with the liquid metal lubricant is formed at the fitting portion between the rotating body and the fixed body.

By the way, when the rotating anode type X-ray tube enters the operating state, the temperature of the anode target rises due to the irradiation of the electron beam. In the rotating anode type X-ray tube using the dynamic pressure type sliding bearing, when the heat of the anode target is released, for example, the heat of the anode target is transferred to the fixed body through the bearing surface filled with the liquid metal lubricant, and the heat is passed through the fixed body. A method of letting it escape to the outside of the tube is adopted (see Japanese Patent No. 2960085 and Japanese Patent Laid-Open Nos. 7-226177 and 9-171789).

[0005]

As described above, in the conventional rotary anode X-ray tube, when the heat of the anode target is released, the heat of the anode target is transferred to the fixed body through the bearing surface, and the fixed body is fixed. Is released through.

However, in the case of the invention of Japanese Patent No. 2960085, the anode target and the rotating body of the rotating mechanism for fixing the anode target come into contact with each other over a wide area. Therefore, more heat is transferred from the anode target to the rotating body. In this case, the material forming the bearing surface of the rotating mechanism and the liquid metal lubricant may interact with each other to roughen the bearing surface or change the size of the bearing gap, so that stable bearing operation may not be maintained.

Further, in the case of the inventions of JP-A-7-226177 and JP-A-9-171789, in order to reduce the heat transferred to the rotating body, thermal resistance is provided between the anode target and the rotating body of the rotating mechanism. A path, for example, a tubular joint portion is provided.

When the joint portion is provided, the anode target is connected to the joint portion, and the joint portion is connected to the rotating body of the rotating mechanism. In this case, for example, one of the connecting portion between the anode target and the joint portion and the connecting portion between the rotating body and the joint portion is integrally formed, and the other is mechanically contacted and fixed with a screw component.

In the case of a structure in which they are in mechanical contact, the thermal resistance is large and a sufficient heat transfer effect cannot be obtained. Further, the magnitude of the thermal resistance depends on the roughness of the surface of the contact portion, and the thermal resistance value varies depending on the processing accuracy. If there is variation in the thermal resistance value, for example, a temperature difference occurs in the rotating body portion in one tube, or a temperature difference occurs in the rotating body portion due to the pipe. In such a case, a safe design in consideration of temperature variations is required, which causes an increase in cost.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a rotating anode type X-ray tube in which variations in heat transferred from an anode target to a rotating body portion of a rotating mechanism are reduced.

[0011]

According to the present invention, there is provided an anode target provided in a vacuum container, a joint portion having a tubular portion as a part and having the anode target joined thereto, and a dynamic pressure type fitting portion. A rotating anode type X-ray tube comprising a rotating body provided with a slide bearing and a fixed body, and a rotating mechanism for rotatably holding the anode target through the joint portion, wherein the anode target and the joint are provided. The parts are metal-bonded or integrally bonded, and the rotating body and the joint part are metal-bonded or integrally bonded.

[0012]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to FIG.

Reference numeral 11 is a vacuum container which constitutes a rotary anode type X-ray tube, and an anode target 12 is arranged in the vacuum container 11. The anode target 12 is connected to the joint portion 13, and is also connected to the rotating mechanism 14 via the joint portion 13.

At least a part of the joint portion 13 is formed in a cylindrical shape in order to suppress heat transferred from the anode target 12 to the rotating mechanism 14, and has a so-called heat resistance structure having a small heat transfer area. An annular stepped portion 15 protruding outward is provided on the outer peripheral surface of the joint portion 13. Joint part 13
Penetrates a through hole in the center of the anode target 12, and a fixing screw 16 is screwed into the upper end of the through hole, and the stepped portion 15 and the fixing screw 1
An anode target 12 is fixed between the anode target 6 and the anode 6. The anode target 12 and the stepped portion 15 are, for example, titanium foil 101.
They are joined together by diffusion joining with the sandwiched between.

The rotating mechanism 14 is composed of, for example, a rotating body such as a rotating cylinder 17 having a bottomed cylindrical shape and a fixed body 18 fitted inside the rotating cylinder 17. Rotating cylinder 1
7 is manufactured integrally with, for example, the joint portion 13, and the rotary cylinder 1
The bottom portion of 7 is integrally connected to the joint portion 13. A tubular member 19 made of copper is joined to the outer peripheral portion of the rotary cylinder 17, and the opening at the lower end of the rotary cylinder 17 in the figure is sealed with a thrust ring 20. The thrust ring 20 is fixed to the rotating cylinder 17, and constitutes the rotating body of the rotating mechanism 14 together with the rotating cylinder 17 and the like.

The fixed body 18 penetrates the thrust ring 20, and the lower end 18a of the fixed body 18 is provided with a sealing member 21 between the vacuum body 1 and the fixed body 18.
It is airtightly bonded to the glass part of No. 1. An elongated hole 22 is formed inside the fixed body 18 along the tube axis, and a pipe 23 is arranged in the hole 22. The holes 22 and the pipe 23 of the fixed body 18 have lower ends shown in the drawing open to the outside of the vacuum container 11, and a cooling passage is formed in the fixed body 18.

A cooling medium, such as insulating oil, flowing through the cooling passage flows from the outside of the vacuum vessel 11 to the outside of the pipe 23 upward as shown in the arrow C1, enters from the upper end into the pipe 23, and enters the pipe 23 downward in the drawing. Flow out to the outside of the vacuum container 11.

Dynamic pressure type sliding bearings 25a and 25b in the radial direction are provided at the fitting portion between the rotary cylinder 17 and the fixed body 18. The dynamic pressure type slide bearings 25a and 25b are composed of, for example, a spiral groove of a herringbone pattern provided on the outer peripheral surface of the fixed body 18, a liquid metal lubricant supplied to the spiral groove portion during operation, or the like. In addition, the fixed body 18
Dynamic pressure type slide bearings 26a, 26b in the thrust direction are provided on the upper end surface of the rotary cylinder 17 and the lower cylinder surface of the fixed body 18 and the thrust ring 20.
The dynamic pressure type slide bearings 26a and 26b are composed of a spiral groove of a herringbone pattern provided on the upper end surface and the lower end surface of the fixed body 18, a liquid metal lubricant supplied to the spiral groove portion during operation, and the like.

Dynamic pressure type slide bearings 25a, 25b, 26
In a region where a and 26b are formed, a so-called bearing region, a gap between the rotating cylinder 17 and the thrust ring 20 and the fixed body 18, for example, a bearing gap is set in a range of about 10 μm to 30 μm.

In the above structure, a rotating force is generated in the tubular member 19 of the rotating mechanism 14 by the rotating magnetic field generated by the stator coil (not shown) arranged outside the vacuum container 11. This rotational force passes through the joint portion 13 and the anode target 12
And the anode target 12 is rotated. In this state, the anode target 12 is irradiated with an electron beam, and the anode target 12 emits X-rays.

When the rotating anode type X-ray tube enters the operating state, the temperature of the anode target 12 rises due to the irradiation of the electron beam. Most of the heat of the anode target 12 is dissipated by radiation. The rotating cylinder 1 of the rotating mechanism 14 partially passes through the joint portion 13.
7 is transmitted to the rotating cylinder 17 and further to the stationary body 18.
And then to the outside from the fixed body 18 directly and via the cooling medium flowing through the cooling passage.

At this time, if the temperature of the bearing region is kept at about 350 ° C. or lower, the reaction between the material forming the bearing surface and the liquid metal lubricant is suppressed, and the roughness of the bearing surface and the dimensional change of the bearing gap are prevented. As a result, stable bearing operation is maintained.

According to the above configuration, the anode target 12
The joint portion 13 and the joint portion 13 are joined by metal joining by diffusion joining, and the rotary cylinder 17 and the joint portion 13 are joined together. In this case, the heat transfer paths from the anode target 12 to the rotating cylinder 17 are all metallographically coupled. As a result, there is no portion in the heat transfer path where the metals simply make mechanical contact with each other, and variation in the thermal resistance value in the heat transfer path is prevented.

In the case of the embodiment shown in FIG. 1, each of the rotary cylinder 17, the fixed body 18, and the thrust ring 20 constituting the rotary mechanism 14 is made of a material such as molybdenum or a molybdenum alloy. These materials are relatively easy to process and inexpensive to construct. However, instead of these materials, tungsten, a tungsten alloy, tantalum, or a tantalum alloy can be used. Materials below tungsten have the advantage that they are less susceptible to corrosion by liquid metal lubricants.

Even when it is made of a material such as molybdenum, at least one surface of the rotary cylinder 17 and the fixed body 18 in the heat transfer region where heat is transferred from the rotary cylinder 17 to the fixed body 18 is made of the following high melting point substance. When the heat resistant coating layer is provided, the temperature of the fitting surface forming the heat transfer area can be increased, and the cooling capacity for the anode target 12 is increased.

In this case, examples of the high melting point substance include oxides and borides of chromium, and nitrides and carbides of vanadium, borides, oxides and nitrides of hafnium, oxides of carbides, borides, and titanium. And nitride, carbide, boride, tungsten, tungsten nitride and carbide, boride, molybdenum, molybdenum nitride and carbide, boride, zirconium oxide and nitride, carbide and boride,
Tantalum, tantalum nitrides and carbides, borides, niobium, niobium nitrides and carbides, borides, ruthenium, rhenium, osmium, iridium, boron nitride, boron carbide, aluminum oxide, aluminum nitride, aluminum carbide, aluminum boride A material containing at least one selected from silicon nitride, silicon carbide, silicon boride, diamond, carbon (including DLC and graphite), magnesium oxide, and beryllium oxide as a main component is used.

It is also possible to employ a structure in which an iron-based metal material mainly composed of iron is used, and the heat-resistant coating layer made of the above-mentioned high melting point material is provided on the fitting surface including the bearing surface.

Here, the anode target 12 and the joint portion 13
A method of diffusion bonding will be described. First, between the anode target 12 and the stepped portion 15 of the joint portion 13, 10 μ
A titanium foil 101 having a thickness of m is arranged as a diffusion promoting material. Further, the fixing screw 16 is screwed into the upper end of the joint portion 13 to fix the anode target 12 between the stepped portion 15 and the fixing screw 14. At this time, the fixing screw 16 is tightened so that the tightening pressure applied to the titanium foil 101 is about 300 kgf / cm ² (approximately 296 atm) or more.

Next, the anode target 12 and the joint portion 1
3. The assembly in which the rotating cylinder 17 and the like are connected is placed on the installation table in the quartz bell jar. Then, while evacuating the inside of the quartz bell jar, an electric current is applied to a high frequency coil arranged outside the quartz bell jar to set the anode target 12 to about 1300.
Heat to ℃. At this time, the heat of the anode target 12 escapes to the installation table via the joint portion 13 and the rotating cylinder 17, and a temperature gradient is generated in the assembly, and the vicinity of the interface between the anode target 12 and the stepped portion 15 with the titanium foil 101 sandwiched therebetween. Reaches a temperature of about 1100 ° C. If this temperature is maintained for about 30 minutes, the mutual diffusion of the titanium element of the titanium foil 101 and the molybdenum element of the anode target 12 and the joint portion 13 proceeds, and the anode target 12 and the joint portion 13 are joined.
After the joining is finished, the heating is finished and after cooling, the assembly is taken out.

Next, the balance of the assembly is corrected, the fixed body 18 is fitted in the rotating cylinder 17, the thrust ring 20 and the like are attached, and the anode target and the rotating mechanism are integrated into a structure.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In FIG. 2, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and overlapping description will be partially omitted.

In the case of this embodiment, the joint portion 13 is composed of a first tubular portion 13a and a second tubular portion 13b whose inner diameter and outer diameter are both larger than that of the first tubular portion 13a. The first tubular portion 13a and the second tubular portion 13b of the joint portion 13 are integrally configured, and are configured separately from the rotary cylinder 17 having a bottomed cylindrical shape. An annular projecting portion 131 that projects outward is provided at the end of the first tubular portion 13 a on the anode target 12 side, and an annular projecting portion 170 is provided on the outer peripheral surface of the rotating cylinder 17.

With the above structure, the joining portion A between the anode target 12 and the annular protruding portion 131 of the joint portion 13 is metal-joined by the friction welding method. The annular lower end surface of the second tubular portion 13b of the joint portion 13 and the annular upper surface of the protruding portion 170 of the rotary cylinder 17 are metal-bonded by diffusion bonding with the titanium foil 102 sandwiched therebetween. In addition, the second tubular portion 13 of the joint portion 13
b and the protrusion 170 of the rotary cylinder 17 are fixed by a fixing screw 202 extending in the tube axis direction.

The anode target 12 and the joint portion 13 are metallographically joined by a friction welding method, and then finished as an integral part.

When the joint portion 13 and the rotary cylinder 17 are diffusion-bonded, first, the gap between the annular lower surface of the second tubular portion 13b of the joint portion 13 and the annular upper surface of the protruding portion 170 of the rotary cylinder 17 is 10 μm. A thick titanium foil 102 is sandwiched as a diffusion promoting material and fixed with a plurality of fixing screws 202. In this case, the tightening pressure applied to the titanium foil 102 is about 300 kgf / c.
Fixing screw 2 so that m ² (approximately 296 atm) or more
Tighten 02.

Next, the anode target 12 and the joint portion 1
3. The assembly in which the rotating cylinder 17 is connected is placed on the installation stand inside the quartz bell jar, and while the vacuum is applied to the quartz bell jar, a current is passed through the high frequency coil placed outside the quartz bell jar to bring the anode target 12 to about 1300 ° C. Heat to.
The heat of the anode target 12 is generated by the joint portion 13 and the rotating cylinder 1.
It escapes to the installation base via 7 and a temperature gradient occurs in the assembly.

At this time, the temperature in the vicinity of the interface between the anode target 12 and the joint portion 13 sandwiching the titanium foil 102 is about 10.
The temperature reaches 00 ° C. and this temperature is maintained for about 1 hour.
As a result, mutual diffusion of the titanium element forming the titanium foil 102 and the molybdenum elements of the anode target 12 and the joint portion 13 progresses, and the joint portion 13 and the rotating cylinder 17 are joined.

After the joining is finished, the heating is finished and the assembly is taken out after cooling. After that, the balance of the assembly is corrected, the fixed body 18 is fitted in the rotating cylinder 17, and the thrust ring 20 is attached.

Also in the case of FIG. 2, the anode target 12 and the joint portion 13 are joined by metal joining, for example, friction welding, and the rotary cylinder 17 and the joint portion 13 are joined by metal joining, for example, diffusion joining. Therefore, the heat transfer path from the anode target 12 to the rotating cylinder 17 portion is metallurgically coupled. Therefore, there is no portion in the heat transfer path where the metal surfaces are simply in contact with each other, and variations in the thermal resistance value in the heat transfer path are prevented.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In FIG. 3, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and overlapping description will be partially omitted.

In the case of this embodiment, the rotary cylinder 17 is composed of a bottom plate portion 17a and a cylindrical portion 17b. For example, the bottom plate portion 17a and the cylindrical portion 17b are manufactured separately, and the bottom plate portion 17a is manufactured integrally with the joint portion 13. Then, the anode target 12 and the joint portion 13
However, as in the case of FIG. 2, they are metallographically bonded by the friction welding method. The bottom plate portion 17a and the cylindrical portion 17b of the rotary cylinder 17 are fixed with a fixing screw 203, and are joined by diffusion joining using the titanium foil 103.

In the case of this structure, the heat of the anode target 12 is transferred from the joint portion 13 to the bottom plate portion 17a, and the bottom plate portion 1
It is transmitted to the fixed body 18 from, for example, the central portion of 7a. Further, the thermal resistance of the joint portion between the bottom plate portion 17a and the cylindrical portion 17b of the rotating cylinder 17 has little influence on the heat radiation characteristics.
Therefore, it is possible to fix only by the fixing screw 203 and omit the diffusion bonding.

Also in the case of FIG. 3, the anode target 12 and the joint portion 13 are joined by metal joining, and the rotary cylinder 17 and the joint portion 13 are joined together.
Are linked together. Therefore, the anode target 12
To the rotating cylinder 17, for example, the bottom plate portion 17a, the heat transfer path is metallurgically coupled, and there is no portion where the metal surfaces are simply in contact with each other, so that the variation of the thermal resistance value is prevented.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In FIG. 4, parts corresponding to those in FIG. 1 are assigned the same reference numerals and overlapping description is partially omitted.

In the case of this embodiment, the anode target 12
A thin portion 12a having a small thickness is provided at the edge of the central through hole. An annular stepped portion 131 protruding outward is provided on the outer peripheral portion of the joint portion 13, and an annular protruding portion 132 protruding inward is provided at the lower end of the joint portion 13 in the drawing.

The rotating cylinder 17 has a small diameter portion 17 having a small inner diameter.
1 and a large-diameter portion 172 having an inner diameter larger than that and a small-diameter portion 171 and formed integrally with each other, and an annular protruding portion 170 is provided on the outer peripheral surface. The fixed body 18 includes a small-diameter portion 181 having a small outer diameter and a large-diameter portion 182 having a larger outer diameter than that and integrally formed with the small-diameter portion 181.
The small diameter portion 181 and the large diameter portion 182 of the fixed body 18 are fitted inside the small diameter portion 171 and the large diameter portion 172 of the rotating cylinder 17.

With the above structure, the thin portion 12a of the anode target 12 is fixed between the fixing screw 204 and the stepped portion 131, and at the same time, the thin portion 12a and the stepped portion 131 are diffusion bonded using the titanium foil 104. Are joined by.
The joint B of the annular protrusion 132 of the joint portion 13 and the annular protrusion 170 of the rotary cylinder 17 is brazed.

In the case of FIG. 4, the small diameter portion 171 of the rotating cylinder 17
And the small diameter portion 181 of the fixed body 18 face each other, the gap between the fitting portions is set in the range of, for example, 30 μm to 500 μm, and the dynamic pressure type slide bearings 25a, 25b, 26a, 26b.
It is formed to be larger than the gap in the bearing region in which is formed, and is filled with the liquid metal lubricant like the bearing region. The fitting portion between the small diameter portion 171 of the rotating cylinder 17 and the small diameter portion 181 of the fixed body 18 has a large gap and forms a non-bearing region having almost no function as a bearing.

This non-bearing region serves as a heat transfer fitting portion 41 for transferring the heat of the anode target 12 transferred to the rotary cylinder 17 to the fixed body 18. The gap of the heat transfer fitting portion 41 is set to be larger than the gap of the bearing region, and is set to a dimension such that the rotating cylinder 17 and the fixed body 18 do not mechanically contact each other in a normal use state. A circle P is an enlarged view of a part of the heat transfer fitting portion 41.

The temperature of the heat transfer fitting portion 41 reaches, for example, 400 ° C. to 500 ° C. during use. At such a temperature, the liquid metal lubricant reacts with the material of the rotary cylinder 17 or the fixed body 18 constituting the heat transfer fitting portion 41, such as molybdenum or molybdenum alloy, and the gap of the heat transfer fitting portion 41 is reduced. It may decrease due to the growth of the reaction layer. However, since the size of the gap is large, deterioration of the rotation characteristics is avoided.

On the other hand, the dynamic pressure type slide bearings 25a, 25b,
The bearing region in which 26a and 26b are formed is farther from the heat transfer path of the anode target 12 than the non-bearing region serving as the heat transfer fitting part 41, and its temperature is maintained at about 250 ° C. or lower. Therefore, the mutual reaction between the bearing material and the liquid metal lubricant in the bearing region is suppressed, the roughness of the bearing surface and the dimensional change are prevented, and stable bearing operation can be maintained.

Further, the fixed body 18 at the portion where the joint portion 13 and the rotary cylinder 17 are joined and the portion at the same position in the pipe axial direction are provided.
A hole 23 is provided inside, and the cooling medium flows to that portion. In this case, the heat of the anode target 12 transferred from the joint portion 13 to the rotating cylinder 17 and transferred from the rotating cylinder 17 to the fixed body is efficiently cooled.

Also in the case of FIG. 4, the anode target 12 and the joint portion 13 are joined by metal joining, and the rotary cylinder 17 and the joint portion 13 are joined together.
Are also joined by metal bonding. Therefore, the heat transfer path from the anode target 12 to the rotating cylinder 17 is metallurgically coupled, and there is no portion where the metal surfaces are simply in contact with each other, and the variation of the thermal resistance value is prevented.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In FIG. 5, parts corresponding to those in FIG. 4 are denoted by the same reference numerals, and overlapping description will be partially omitted.

In this embodiment, the inner diameter of the rotary cylinder 17 and the outer diameter of the fixed body 18 are formed to be uniform, and the fixed body 18 is fitted in the rotary cylinder 17. In the case of this structure, as compared with the structure of FIG. 4, the outer diameter and the inner diameter of the rotating cylinder 17 and the fixed body 18 near the anode target 12 side are increased, and the diameter of the hole 22 forming the cooling passage is also increased. 12 side is larger.

In addition, the fixed body 18 and the hole 2 and the first portion 18A in which the diameter of the hole 22 of the cooling passage is formed large, for example.
The second portion 18B having a smaller diameter 2 is formed separately, and the first portion 18A and the second portion 18B are joined to each other by the joining portion 18
It is diffusion bonded at C.

In the case of FIG. 5, the cooling medium flowing in the cooling passage rises in the pipe 23, moves from the upper end to the outside of the pipe 23, and descends as shown by an arrow C2. There is.

In the structure of FIG. 5, the area where the upper end surface of the fixed body 18 and the rotating cylinder 17 face each other is the rotating cylinder 1
The distance from the connecting portion between 7 and the joint portion 13 is small, and the upper end surface of the fixed body 18 and the fitting portion of the rotary cylinder 17 form another heat transfer fitting portion 41a. In this case, the fitting surface that forms the bearing and the fitting surface for heat transfer are formed as a common fitting surface, and part of the heat transferred from the joint portion 13 to the rotating cylinder 17 is fitted for heat transfer. It is transmitted to the fixed body 18 via the portion 41a.

According to the above structure, the contact area between the fixed body 18 and the cooling medium is increased, and the heat transfer coefficient from the anode target 12 to the cooling medium, that is, the cooling efficiency of the anode target 12 is improved.

Also in the case of FIG. 5, the anode target 12 and the joint portion 13 are joined by metal joining, and the rotary cylinder 17 and the joint portion 13 are joined together.
Are also joined by metal bonding. Therefore, the heat transfer path from the anode target 12 to the rotating cylinder 17 is metallurgically coupled, and there is no portion where the metal surfaces are simply in contact with each other, and the variation of the thermal resistance value is prevented.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In FIG. 6, parts corresponding to those in FIG. 4 are denoted by the same reference numerals, and overlapping description will be partially omitted.

In this embodiment, the rotary cylinder 17 has a small diameter portion 17A having a small outer diameter and a large diameter portion 17B having a larger outer diameter than the small diameter portion 17A, and the small diameter portion 17A and the large diameter portion 17B are formed separately. It joins at the joining part 61. The fixed body 18 includes a small diameter portion 181 having a small outer diameter and a large diameter portion 18 having a large outer diameter.
2 are configured separately, and the small diameter portion 181 and the large diameter portion 182 are joined at the joining portion 62. The small diameter portion 181 and the large diameter portion 182 of the fixed body 18 are fitted inside the rotary cylinder 17, respectively.

The small diameter portion 17A of the rotary cylinder 17 and the small diameter portion 181 of the fixed body 18 are made of a first material such as molybdenum.
It is made of a material selected from molybdenum alloy, tungsten, tungsten alloy, tantalum, and tantalum alloy. Large diameter portion 17B of rotating cylinder 17 and fixed body 18
The large diameter portion 182 of the second material is, for example, iron (Fe), steel,
It is composed of a metal mainly composed of iron such as alloy steel, iron-nickel alloy, iron-chromium alloy, or iron-nickel-chromium alloy.

The fitting portion between the small diameter portion 17A of the rotary cylinder 17 and the small diameter portion 181 of the fixed body 18 is the heat transfer fitting portion 41.
Is formed. In this case, the fitting portion between the bottom surface of the rotary cylinder 17 and the upper end surface of the fixed body 18 is also close to the joint portion between the joint portion 13 and the rotary cylinder 17, and functions as the heat transfer fitting portion 41a.

In the case of FIG. 6, the joint portions 61 and 62 are structured to come into contact with the liquid metal lubricant. Joints 61, 62
With brazing filler metals, almost all brazing filler metals are attacked by liquid metal lubricants. Therefore, the joint portion 61,
The welding of 62 is performed by a diffusion welding method such as friction welding.

In the case of the above structure, the dynamic pressure type sliding bearing 2
The bearing region provided with 5a, 25b, 26a, 26b is formed of, for example, a material mainly containing iron. Therefore, it is possible to process the bearing with high accuracy. In addition, iron and iron alloys are relatively inexpensive and easier to process than molybdenum and tungsten. Further, since it is a ferromagnetic material, the efficiency of magnetic coupling with the rotating magnetic field is increased.

When molybdenum or a molybdenum alloy is selected as the material for forming the fitting surfaces of the heat transfer fitting portions 41 and 41a, there is an advantage that processing is easy and the cost can be reduced. However, it has a drawback that it is more likely to be eroded by the liquid metal lubricant than when tungsten or tantalum is selected. However, if the heat-resistant coating layer of the high melting point material, for example, ceramics such as titanium nitride described in FIG. 1 is provided on the fitting surfaces of the heat transfer fitting portions 41 and 41a, the mechanical strength at high temperature becomes high. Also, corrosion by the liquid metal lubricant is eliminated. Further, it is possible to cope with the temperature rise of the fitting surface, and the cooling capacity of the anode target 12 is increased.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In FIG. 7, parts corresponding to those in FIG. 6 are denoted by the same reference numerals, and overlapping description will be partially omitted.

In the case of this embodiment, for example, the entire fixed body 18 is integrally formed by using a metal mainly composed of iron, which is easy to process and inexpensive, as a base material. Further, as shown in an enlarged circle Q of a part of the heat transfer fitting portion 41, the fixed body 1
The heat resistant coating layer 71 made of the high melting point material described in FIG. 1 is provided on the fitting surface of No. 8.

As a method of forming the heat resistant coating layer 71, for example, a portion other than the portion to be the heat transfer fitting surface 41 is masked, and the surface to be the heat transfer fitting surface 41 is subjected to a CVD (chemical vapor deposition) method or a PACVD (PCVD) method. Plasma activated chemical vapor deposition) method, M
A method of depositing a high melting point substance to a thickness of about 0.5 μm to 20 μm by an OCVD (metal organic chemical vapor deposition) method, a PVD (physical vapor deposition) method such as ion plating, or a thermal spraying method is used. In addition, a molten salt bath dipping method, a heat treatment method in a gas atmosphere, etc. are also adopted.

In FIG. 7, molybdenum or molybdenum alloy, which is easy to process and inexpensive, is used for the rotary cylinder 17 forming the heat transfer fitting portions 41, 41a. However, it is also possible to use tungsten, tungsten alloys, tantalum, tantalum alloys. Materials such as molybdenum are more susceptible to corrosion by liquid metal lubricants than materials such as tungsten. Also in this case, the heat transfer fitting surface of the rotating cylinder 17
Heat-resistant coating layer 7 made of high-melting point material described in FIG.
If 1 is provided, it can cope with the temperature rise and the anode target 1
The cooling capacity of 2 is increased.

The heat-resistant coating layer 71 is preferably formed on the heat transfer fitting surface where the rotary cylinder 17 and the fixed body 18 do not mechanically contact each other. However, if the coating layer has high adhesion and wear resistance, it can be formed on the bearing surface.

As the material of the coating layer, a mixture of the high melting point substances described in FIG. 1 is used. Also,
These may contain a small amount of another substance.

Next, FIG. 8 shows another embodiment of the present invention.
Will be described with reference to. In FIG. 8, parts corresponding to those in FIG. 6 are denoted by the same reference numerals, and overlapping description will be partially omitted.

In the case of this embodiment, the upper end of the fixed body 18 in the figure is fixed to a part of the vacuum container 11. For example, a cylindrical first fixing member 81 is airtightly joined to a part of the vacuum container 11. The tubular second fixing member 82 is airtightly joined to the bent portion 81a that is bent inward at the upper end of the first fixing member 81, and the tubular third fixing member 83 is airtightly joined to the inside of the second fixing member 82. ing. The upper end of the fixed body 18 in the figure is airtightly fixed inside the third fixing member 83.

The fixed body 18 is formed by joining different materials at the first and second joining portions 84a and 84b, and the annular enlarged portion 8 is provided in the portion adjacent to the thrust ring 20.
4 are formed. Further, the fixed body 18 is provided with a hole 22 penetrating in the pipe axis direction from the upper end surface to the lower end surface thereof to form a cooling medium passage. Both upper and lower ends of the hole 22 are opened to the outside of the vacuum container 11, and as shown by an arrow C3, the cooling medium enters from the opening at the lower end and is led out from the opening at the upper end.

The rotary cylinder 17 is also constructed by joining different materials at the joint portion 85 located at the same position as the second joint portion 84b in the tube axis direction. The joint portion 13 is coupled to the portion of the first rotary body 86a located above the joint portion 85 with the same structure as in FIG.

Further, radial dynamic pressure type slide bearing types 25a and 25b are formed in the fitting portion of the second rotating body 86b and the fixed body 18 located below the joint portion 85 of the rotary cylinder 17. The upper surface of the enlarged portion 84 and the second rotating body 86b
Are opposed to each other and the lower surface of the enlarged portion 84 and the thrust ring 20 are opposed to each other. Dynamic pressure type slide bearings 26a and 26b are formed in the thrust direction. Also, the first
The fitting portion of the rotating body 86a and the fixed body 18 is the heat transfer fitting portion 4
Make up one.

First rotating body 86a and first rotating body 86a
The portion of the fixed body 18 that fits into the second rotary body 86b and the portion of the fixed body 18 that fits into the second rotary body 86b are made of the second material described in FIG. It is configured.

In FIG. 8, both ends of the fixed body 17 are vacuum containers 11
It is fixed to. Therefore, the anode target 12 and the rotating mechanism 14 are stably supported. Further, since the dynamic pressure type slide bearing is provided on one side of the anode target 12, the outer diameter of the rotating body located on the cathode side can be reduced, and the withstand voltage performance can be secured.

When the rotary anode type X-ray tube shown in FIG. 8 is used for anode grounding, a member for fixing the fixed body 18 to the vacuum container 11, for example, the first fixing member 81 or the second fixing member 82,
The third fixing member 83 is made of metal.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In FIG. 9, parts corresponding to those in FIG. 8 are designated by the same reference numerals, and overlapping description will be partially omitted.

In the case of this embodiment, the rotary cylinder 17 is composed of, for example, a cylindrical portion 91 and a sealing ring 92 for sealing the opening above this. In the cylindrical portion 91, different materials are joined at the two joining portions 94a and 94b, and
Intermediate cylindrical portion 91a sandwiched between two joints 94a and 94b
The joint portion 13 is coupled to the. The intermediate cylindrical portion 91a is
The upper cylindrical portion 91b and the sealing ring 92, which are made of the first material described in FIG. 6 and are located above the joining portion 94a,
A lower cylindrical portion 91c located below the joining portion 94b,
The thrust ring 20 is made of the second material described with reference to FIG. Further, below the thrust ring 20, a conductive tubular member 110 that produces a rotational force by a rotating magnetic field generated by a stator coil (not shown) is provided.

The upper end of the fixed body 18 penetrates the sealing ring 92, extends upward, and is fixed to the vacuum container 11. The lower end of the fixed body 18 penetrates the thrust ring 20 and extends downward. The fixed body 18 has two joints 9
Different materials are joined by 5a and 95b, and the intermediate portion 180a sandwiched by the two joining portions 95a and 95b is composed of the first material described in FIG. The upper portion 180b located above the joining portion 95a and the lower portion 180c located below the joining portion 95b are the second portion described in FIG.
Composed of materials.

The fitting portion between the intermediate cylindrical portion 91a of the rotary cylinder 17 and the intermediate portion 180a of the fixed body is the heat transfer fitting portion 41.
And the hole 22 constituting the passage for the cooling medium has a large inner diameter at the intermediate portion 180a of the fixed body.

The radial dynamic pressure type slide bearings 25a and 25b are formed in the upper cylindrical portion 91b and the lower cylindrical portion 91c of the rotary cylinder 17, and the thrust dynamic pressure type sliding bearings 26a and 26b are The sealing ring 92 and the thrust ring 20 are formed on the facing portion of the fixed body 18.

In the case of FIG. 9, since both ends of the fixed body 17 are fixed to the vacuum container 11, the anode target 12 and the rotating mechanism 14 are stably supported. Further, dynamic pressure type slide bearing bearings 25 a, 25 b, 26 a, 26 b are arranged on both sides of the anode target 12. In this case, the load loads applied to the upper and lower bearings are well balanced, and a stable bearing function is realized.

In the case of the structure shown in FIG. 9, a refractory metal such as molybdenum or an iron alloy such as SKD11 can be used as the material forming the bearing surface. High-melting-point metals are prone to galling and have problems such as high material and processing costs. In the case of an iron alloy, galling is unlikely to occur and the material and processing cost are reduced, but there is a problem that it easily reacts with the liquid metal lubricant. However, if a cooling medium passage is provided in the fixed body to cool the stationary body, the reaction with the liquid metal lubricant can be suppressed. Therefore, the use of iron alloy has a great advantage.

On the other hand, for the material forming the heat transfer fitting surface,
It is desirable to employ a refractory metal such as molybdenum on the rotating side that is joined to the joint. In this case, in order to prevent the gap size from changing due to a difference in thermal expansion due to a temperature rise during use, it is desirable to use a high melting point metal also on the fixed body side. However, the gap between the heat transfer fitting portions is not required to have dimensional accuracy higher than that of the bearing portion.

In each of the above embodiments, for example, when the bearing fitting surface and the heat transfer fitting surface are not common, a herringbone pattern groove or a spiral pattern groove may be formed on the heat transfer fitting surface. it can. Since the groove has a function of holding the liquid metal lubricant in the fitting gap, good heat transfer from the rotating body to the fixed body is realized.

When diffusion bonding is performed in the above embodiment, titanium foil is used as a diffusion promoting material. However, other diffusion promoting materials such as Ti, Pt, Zr,
A material having a saturated vapor pressure of 1 × 10 ⁻⁶ Pa or less at 1000 ° C. such as a material selected from V, Rh, and alloys containing these metals as a main component is used.

Further, the diffusion promoting material is arranged so as to be sandwiched between two members to be joined. However, a method of applying the diffusion promoting material to the surfaces of the members to be joined may be used.

In FIGS. 8 and 9, when the rotating body portion and the fixed body portion are formed, different materials are joined at the joining portion. However, the rotating body portion and the fixed body portion can be integrally formed by using the same material. When integrally formed, the joint portion is not corroded by, for example, a liquid metal lubricant, and the mechanical strength is increased.

According to the above structure, there is no variation in the thermal resistance in the heat transfer path through which the heat of the anode target is transferred. In this case, the amount of heat transferred from the rotating body to the fixed body can be increased within a range in which stable bearing operation cannot be maintained due to the reaction between the material forming the bearing surface and the liquid metal lubricant. As a result, the amount of heat transferred to the cooling fluid flowing inside the fixed body can be increased, and the characteristics of the rotary anode type X-tube are improved.

[0095]

According to the present invention, a rotary anode type X-tube having a heat transfer path with little variation in thermal resistance is realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view for explaining an embodiment of the present invention.

FIG. 2 is a sectional view for explaining another embodiment of the present invention.

FIG. 3 is a sectional view for explaining another embodiment of the present invention.

FIG. 4 is a sectional view for explaining another embodiment of the present invention.

FIG. 5 is a sectional view for explaining another embodiment of the present invention.

FIG. 6 is a sectional view for explaining another embodiment of the present invention.

FIG. 7 is a sectional view for explaining another embodiment of the present invention.

FIG. 8 is a sectional view for explaining another embodiment of the present invention.

FIG. 9 is a sectional view for explaining another embodiment of the present invention.

[Explanation of symbols]

11 ... Vacuum container 12 ... Anode target 13 ... Joint 14 ... Rotation mechanism 15 ... Stepped part 16 ... Fixing screw 17 ... Rotating cylinder 18 ... Fixed body 19 ... Cylindrical member 20 ... Thrust ring 21 ... Sealing member 22 ... hole 23 ... Pipe 25a, 25b ... Dynamic pressure type sliding bearing in radial direction 26a, 26b ... Dynamic pressure type sliding bearing in thrust direction

Claims (9)

[Claims] 1. A rotating body provided with an anode target provided in a vacuum container, a joint part having a tubular portion as a part, to which the anode target is joined, and a dynamic pressure type slide bearing provided in the fitting portion. And a rotating mechanism having a fixed body and rotatably holding the anode target through the joint portion, in a rotary anode X-ray tube, the anode target and the joint portion being metal-bonded or integrally bonded The rotary anode type X-ray tube is characterized in that the rotating body and the joint portion are metal-bonded or integrally joined together. 2. The rotary anode X-ray tube according to claim 1, wherein at least one of a metal joint connecting the anode target and the joint portion and a metal joint connecting the rotating body and the joint portion is a metal diffusion joint. 3. The rotating anode type X-ray tube according to claim 1, wherein a hole through which a cooling medium flows is provided inside the fixed body of the rotating mechanism. 4. The rotary anode type X-ray tube according to claim 3, wherein the hole through which the cooling medium flows is provided at least in a portion of the fixed body having the same axial position as the joint portion where the joint portion and the rotor are joined. . 5. A non-bearing fitting region having a gap larger than a gap of a bearing region where a hydrodynamic slide bearing is provided is provided in a part of a region where the rotating body and the fixed body are fitted, and the joint portion is Coupled to the rotating body portion in the non-bearing fitting region,
The rotary anode type X-ray tube according to any one of claims 1 to 3, wherein a liquid metal lubricant is supplied to the non-bearing fitting region. 6. The rotary anode type X-ray tube according to claim 5, wherein at least one of the rotating body and the fixed body fitted in the non-bearing fitting region is made of a high melting point metal. 7. At least one of the rotating body and the fixed body is configured by joining a refractory metal material and an iron alloy material, a bearing region portion is formed of the iron alloy material, and a non-bearing fitting region portion. The rotary anode type X-ray tube according to claim 5, wherein is formed of the refractory metal material. 8. The at least one of a rotating body and a fixed body fitted in the non-bearing fitting region is formed of one of molybdenum and a molybdenum alloy, tungsten, a tungsten alloy, tantalum, and a tantalum alloy. The rotating anode X-ray tube described. 9. At least one of a rotating body and a fixed body fitted in the non-bearing fitting region is made of molybdenum and one of molybdenum alloy, tungsten, tungsten alloy, tantalum, and tantalum alloy, and has a surface. The rotary anode type X-ray tube according to claim 5, wherein a coating layer of a high melting point substance is provided.