JP2003272548A - Rotating anode X-ray tube - Google Patents

Abstract

(57) [Problem] To provide a rotating anode type X-ray tube capable of efficiently transmitting heat of an anode target to a cooling medium. SOLUTION: An anode target 12 that emits X-rays,
Hydrodynamic sliding bearings Ra, Rb using liquid metal lubricant
In a rotary anode X-ray tube having a rotating body 17 and a fixed body 18 provided with Sa and Sb at fitting portions and a rotation supporting mechanism 14 rotatably supporting the anode target 12, a fixed body 18 is provided. Cavity 22 through which the cooling medium flows
Are provided in the tube axis direction, and an enlarged portion 22 a having a large inner diameter is provided in a part of the cavity 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary anode type X-ray tube incorporated in a medical diagnostic apparatus or the like.

[0002]

2. Description of the Related Art A rotary anode type X-ray tube is an electron tube for generating X-rays. An anode target placed in a vacuum container is rotatably supported by a rotary support mechanism, and an electron beam is emitted to a high speed rotating anode target. The structure is such that irradiation is performed and X-rays are emitted from the anode target. The rotary support mechanism that supports the anode target is composed of a rotating portion and a fixed portion that are fitted to each other, and a bearing portion is provided at the fitting portion of both.

In the bearing portion, a rolling bearing such as a ball bearing or a spiral groove is formed on the bearing surface to form gallium (Ga) or gallium-indium-tin (Ga-).
A dynamic pressure type slide bearing is used in which a liquid metal lubricant such as an In-Sn) alloy is supplied to the spiral groove portion.

When the latter dynamic pressure type slide bearing is used, the respective bearing surfaces of the rotating portion and the fixed portion are opposed to each other over a wide area via the liquid metal lubricant. Therefore,
When the heat of the anode target is released to the outside of the X-tube, for example, a method has been proposed in which the heat is transferred from the rotating portion to the fixed portion via the liquid metal lubricant and is cooled by a cooling medium flowing in the fixed portion. An example of this is Japanese Patent No. 1828025.
No. 2983617 and No. 285653.
No. 1, JP-A-6-162973, JP-A-7-1058.
No. 87 and Japanese Patent Application Laid-Open No. 9-171789.

[0005]

In the conventional rotating anode type X-ray tube, when the heat of the anode target is released, for example, the heat is transferred from the rotating portion to the fixed portion and finally provided in the fixed portion. The structure is such that it is transmitted to the cooling medium flowing through the cooling passage.

In this structure, the amount of heat transferred to the cooling medium increases as the effective contact area with the cooling medium flowing through the fixed portion increases. The effective contact area is the area of the portion of the inner wall surface of the cooling passage provided in the fixed portion where the heat of the anode target is effectively transmitted, for example, the portion of the inner surface of the cavity forming the cooling passage where the temperature is high.

By design, the temperature T1 on the heat transfer surface of the liquid metal lubricant does not cause a dimensional change due to the mutual reaction between the members constituting the rotating part and the fixed part and the liquid metal lubricant, and stable bearing operation is achieved. Within a range in which the temperature T1 can be maintained and the difference ΔT = T1−T0 between the temperature T1 and the temperature T0 of the cooling medium.
Is within the specified standard range (about 2% of the upper limit when the rejection medium is oil)
Increasing the effective contact area in the range from 00 ° C. to the lower limit of about 150 ° C.) is a standard for improving cooling performance.

However, when miniaturizing the rotary anode type X-ray tube, the outer diameter of the fixed portion becomes smaller, and the inner diameter of the cooling passage provided therein becomes smaller. Therefore, it becomes difficult to secure a large effective contact area.

Japanese Unexamined Patent Publication (Kokai) No. 6-162973 discloses a structure in which a sheet-shaped metal member is brazed to the inner surface of a cavity serving as a cooling passage to increase a contact area with a cooling medium. However, in this method, the contact area between the inner surface of the cavity of the fixed portion and the metal member is small, good heat transfer from the fixed portion to the metal member cannot be obtained, and the cooling efficiency decreases. Further, since it is a method of brazing a metal member, it is difficult to control the flow of the molten brazing material, and it is difficult to perform uniform brazing without defects. Therefore, heat transfer varies, and cooling efficiency decreases.

Further, Japanese Patent Application Laid-Open No. 7-105887 discloses a structure in which a sheet-shaped heat dissipation member is brazed to the inner surface of a cavity serving as a cooling passage to increase a contact area with a cooling medium. However, even in the case of this method, Japanese Patent Laid-Open No. 6-16
It has the same drawbacks as the structure of No. 2973.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a rotating anode type X-ray tube capable of efficiently transferring the heat of the anode target to a cooling medium.

[0012]

The present invention has an anode target which emits X-rays, a dynamic pressure type sliding bearing using a liquid metal lubricant, and a rotary portion and a fixed portion which are provided in a fitting portion. In a rotating anode type X-ray tube comprising a rotating support mechanism that rotatably supports an anode target, a cavity through which a cooling medium flows is provided inside the fixed portion in the tube axis direction, and a part of the cavity is provided. It is characterized in that an enlarged portion having a large inner diameter is provided.

[0013]

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 that constitutes a rotary anode type X-ray tube, and a part thereof is shown in the drawing. An anode target 12 is arranged in the vacuum container 11, and the anode target 12 is connected to the joint portion 13.

The joint portion 13 is formed in a tubular shape, for example, and is composed of a first tubular portion 13a and a second tubular portion 13b having an inner diameter and an outer diameter larger than that of the first tubular portion 13a. Anode target 12 of the first tubular portion 13a
An annular protrusion 131 that protrudes outward is provided at the end on the side, and the anode target 12 is joined to the annular protrusion 131. Further, the joint portion 13 is connected to a rotation support mechanism 14 that rotatably supports the anode target 12.

The rotary support mechanism 14 is composed of a rotary portion and a fixed portion. The rotating portion is composed of the rotating body 17 and the like. The rotating body 17 is composed of, for example, a tubular portion 17a and a disc-shaped bottom portion 17b, and the joint portion 13 is connected to the outer peripheral portion of the tubular portion 17a. For example, an annular protruding portion 171 is provided on the outer peripheral surface of the tubular portion 17a, and the joint portion 13 is connected to the annular protruding portion 171 by a screw S1 and diffusion bonding. The joint surface P of the annular protrusion 171 and the joint portion 13 is, for example, orthogonal to the tube axis m.

A cylindrical rotor 1 made of copper is provided on the outer peripheral portion of the rotating body 17.
9 is joined, and the opening at the lower end in the figure is sealed with a thrust ring 20. The thrust ring 20 is the rotating body 1
The rotary support mechanism 14 is fixed to the rotor 7, and constitutes the rotary portion of the rotary support mechanism 14 together with the rotor 17 and the tubular rotor 19. A fixed body 18 is fitted inside the rotating body 17.

The fixed body 18 constitutes a fixed portion of the rotation support mechanism 14, and has a large outer diameter smaller than the large diameter portion 18a and the large diameter portion 18a fitted inside the rotating body 17 and the thrust ring 20. The small diameter portion 18b penetrating therethrough is configured. The small diameter portion 18b is hermetically bonded to the glass portion of the vacuum container 11 via the sealing member 21. An elongated cavity 22 is formed inside the fixed body 18 along the tube axis m. The cavity 22 is opened outside the vacuum container 11 at the lower end in the figure and is closed at the anode target 12 side at the upper end in the figure.

An enlarged portion 22a having a large inner diameter is provided in a part of the cavity 22. The enlarged portion 22a is provided, for example, in a region surrounded by the joint surface 102 between the rotating body 17 and the joint portion 13 and in the vicinity of the upper and lower portions in the figure in the pipe axis m direction of this region. A tubular cooling medium guiding structure 23 is arranged in the cavity 22. The cooling medium guide structure 23 has a large outer diameter at the enlarged portion 22a of the cavity 22, and forms a cooling passage between the cooling medium guiding structure 23 and the fixed body 18 through which a cooling medium, for example, insulating oil flows.

The cooling medium flows upward from the inside of the cooling medium guiding structure 23 from the outside of the vacuum container 11 as shown by an arrow Y1, and from the upper end to the outside of the cooling medium guiding structure 23 as shown by an arrow Y2. Flowing downward in the figure, vacuum container 1
1 out of 1.

Further, a dynamic pressure type sliding bearing Ra in the radial direction is fitted to a fitting portion of the rotating body 17 and the fixed body 18 in the pipe axis m direction,
Rb is provided. The upper end surface of the fixed body 18 and the rotating body 1
Dynamic pressure type slide bearings Sa and Sb in the thrust direction are provided at the portion of 7 facing the disk-shaped bottom portion 17a and the portion of the step surface of the fixed body 18 facing the thrust ring 20.
The dynamic pressure type sliding bearings Ra, Rb, Sa and Sb are formed by a herringbone pattern spiral groove or the like, and a liquid metal lubricant is supplied to the spiral groove portion during operation.

In the above-mentioned structure, a rotating magnetic field generated by a stator coil (not shown) arranged outside the vacuum container 11 produces a rotating force on the cylindrical rotor 19 of the rotation supporting mechanism 14. This rotational force is transmitted to the anode target 12 via the joint portion 13, and the anode target 12 rotates. In this state, the anode target 12 is irradiated with an electron beam,
X-rays are emitted from the anode target 12.

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. Part of the heat of the anode target 12 is radiated. The remaining part is transmitted to the rotary body 17 of the rotary support mechanism 14 that is mechanically and thermally coupled via the joint surface 13 and the like through the joint portion 13. After that, it is further transmitted from the rotating body 17 to the fixed body 18, and is discharged from the fixed body 18 directly to the outside through the cooling medium flowing through the cooling passage.

According to the above structure, the enlarged portion 22a having a large inner diameter is formed in a part of the cavity 22 in the fixed body 18. Therefore, the contact area between the heat of the anode target 12 transferred to the cavity 22 and the cooling medium is increased, and the heat dissipation effect is improved. Further, in the enlarged portion 22a of the cavity 22, since the thickness of the fixed body 18 is thin, the transfer efficiency of the heat transferred to the fixed body 18 to the cooling medium is improved. Further, the outer diameter of the cooling medium guide structure 23 is increased in accordance with the enlarged portion 22a of the cavity 22. In this case, the speed of the cooling medium flowing through the expanded portion 22a does not decrease, and a good heat dissipation effect can be obtained.

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.

In the case of this embodiment, the anode target 12
A thin portion 121 having a small thickness is provided at the edge of the central through hole. An outer protruding portion 131 that annularly protrudes outward is provided on the outer peripheral portion of the joint portion 13, and an inward protruding portion 132 that annularly protrudes inward is provided at the lower end of the joint portion 13 in the drawing. The thin portion 121 of the anode target 12 is fixed between the fixing screw S2 and the outer protruding portion 131, and at the same time, the thin portion 121 and the outer protruding portion 131 are joined by diffusion bonding using titanium foil or the like. .

The rotating body 17 constituting the rotating portion of the rotation support mechanism 14 includes a cylindrical portion 17a and an annular disc-shaped bottom portion 17.
b, a small-diameter tubular portion 17c, etc., and a tubular portion 17a
An annular protrusion 171 that annularly protrudes is provided on the outer peripheral surface of the. The ring-shaped protrusion 171 is provided with an inward protrusion 1 of the joint portion 13.
32 is joined.

The fixed body 18 constituting the fixed portion of the rotary support mechanism 14 has a large diameter portion 18a fitted to the cylindrical portion 17a of the rotary body 17 and a first small diameter portion fitted to the small diameter cylindrical portion 17c. 181, and a second small diameter portion 182 penetrating the thrust ring 20 and extending therebelow.

Further, in a part of the fitting portion where the rotating body 17 and the fixed body 18 are fitted, for example, in an area A substantially parallel to the enlarged portion 22 of the cavity 22, the dynamic pressure type sliding bearing Ra whose fitting gap has a radial direction, A non-bearing gap having a gap larger than the fitting gap of the Rb portion is formed. In this area A,
During operation, the liquid metal lubricant is filled.

Also in the case of the above-mentioned structure, an enlarged portion 22a having a large inner diameter is formed in a part of the cavity 22 in the fixed body 18, for example, in the vicinity of a region surrounded by the joint surface P. Therefore, the contact area between the heat of the anode target 12 transferred to the fixed body 18 and the cooling medium is increased, and the heat dissipation effect is improved.

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 FIGS. 1 and 2 are denoted by the same reference numerals, and overlapping description will be partially omitted.

Vacuum container 11 constituting a rotary anode type X-ray tube
In the figure, a part 11a of the grounding side container located at one end
And a part 11b of the anode side container located at the other end is shown. Anode target 1 arranged in vacuum container 11
2 is provided with an annular step portion 31 at the edge of the central through hole, and the step portion 31 has an outer protruding portion 13 located at the upper end of the joint portion 13.
1 is joined.

The rotating body 17 constituting the rotating portion of the rotation support mechanism 14 is formed in a cylindrical shape. And the rotating body 1
7 to the annular protrusion 171 provided on the outer peripheral surface of the joint portion 13
The inward protruding portion 132 is fixed by a screw S3 and simultaneously diffusion-bonded. The upper and lower openings of the rotating body 17 in the figure are sealed by the first thrust ring 32 and the second thrust ring 33, and the cylindrical rotor 34 is fixed below the second thrust ring 33. First thrust ring 32, second thrust ring 33, cylindrical rotor 34
Together with the rotating body 17 constitute a rotating portion.

The fixed body 18 constituting the fixed portion of the rotary support mechanism 14 is formed in a cylindrical shape as a whole, and for example, the rotary body 1
7, a large diameter portion 18a having a large outer diameter and a first small diameter portion 18 extending upward through the first thrust ring 32.
The first and second thrust rings 33 are configured to include a second small diameter portion 182 that extends to the outside of the vacuum container 11 below the first and second thrust rings 33. In this case, the enlarged portion 22a of the cavity 22 having a large inner diameter is provided in the large diameter portion 18a, and the inner diameter of the cavity 22 in the first small diameter portion 181 and the second small diameter portion 182 is larger than that of the large diameter portion 18a. It is getting smaller. And
The illustrated upper end of the first small diameter portion 181 is fixed to a part of the vacuum container 11a.

For example, a cylindrical first fixing member 35 is airtightly joined to a part of the vacuum container 11a. The tubular second fixing member 36 is airtightly joined to the bent portion 35a bent inside the upper end of the first fixing member 35, and the tubular third fixing member 37 is airtightly joined to the inner side of the second fixing member 36. ing.
The upper end of the fixed body 18 shown in the drawing, for example, the first small diameter portion 18
1 is airtightly fixed inside the third fixing member 37.

A cooling medium guide structure 23 is arranged in a cavity 22 penetrating from the upper end surface to the lower end surface of the fixed body 18 in the pipe axis direction. The cooling medium guiding structure 23 is formed in, for example, a solid columnar shape, and is located in the large diameter portion 230 located in the large diameter portion 18a of the fixed body 18 and in the first small diameter portion 181 and the second small diameter portion 182. The first and second small diameter portions 231 and 232 are smaller in outer diameter than the large diameter portion 230. At this time, a cooling passage is formed between the cooling medium guide structure 23 and the fixed body 18. For example, the upper and lower ends of the cavity 22 are opened to the outside of the vacuum container 11, and as shown by an arrow Y, the cooling medium enters, for example, through the opening 221 at the lower end and exits through the opening 222 at the upper end.

In the case of the above construction, for example, the joint surface P
An enlarged portion 22a of the cavity 22 is formed in a region surrounded by
The contact area between the heat of the anode target 12 transferred to the fixed body 18 and the cooling medium is increased, and the heat dissipation effect is improved.

In the embodiment shown in FIG. 3, both ends of the fixed body 18 are fixed to the vacuum container 11. Therefore, the anode target 12 and the rotation support mechanism 14 are stably supported. Further, since the dynamic pressure type sliding bearings Ra, Rb, Sa and Sb are arranged on both sides of the anode target 12, the load balance applied to the upper and lower bearings is well balanced and a stable bearing function is realized.

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 FIGS. 1 to 3 are denoted by the same reference numerals, and overlapping description will be partially omitted.

In the case of this embodiment, the anode target 12
The joint portion 13 and the joint portion 13 are connected in the same manner as in FIG.
The upper end in the figure of 8 is fixed in the same manner as in FIG.

The joint portion 13 is composed of a first tubular portion 13a and a second tubular portion 13b having an inner diameter larger than that of the first tubular portion 13a, and the second tubular portion 13b of the joint portion 13 has a rotation support mechanism 14.
Is connected to a portion of the rotating body 17.

The rotating body 17 is formed in a tubular shape and has, for example, a first portion 41 extending inward of the anode target 12 and a second portion 42 having a larger inner diameter than the first portion 41 and a larger inner diameter than the second portion 42. It is composed of a third portion 43, an annular connecting portion 44 that connects the first portion 41 and the second portion 42, and the like. Then, on the outer surface of the annular protrusion 171 that slightly protrudes to the outer peripheral portion of the second portion 42, the second portion of the joint portion 13 is formed.
The inner surface of the tubular portion 13b is joined. In this case, the joint surface P between the joint portion 13 and the rotating body 17 is parallel to the tube axis m. The opening below the third portion 43 in the figure is sealed by the thrust ring 20. The tubular rotor 19 is provided so as to surround the second portion 42, and the tubular rotor 19 is joined to the second portion 42 and the third portion 43. The thrust ring 20 and the tubular rotor 19 together with the rotating body 17 form a rotating portion of the rotation support mechanism 14. A fixed body 18 constituting a fixed portion of the rotation support mechanism 14 is fitted inside the rotary body 17 and the thrust ring 20.

The fixed body 18 is the first portion 41 of the rotating body 17.
The first portion 46 which is fitted to the first portion 46 and the second portion 47 which is fitted to the second portion 42 of the rotating body 17, the rotating body 1
The third portion 48 of the seventh portion 48 is fitted to the third portion 43, and the fourth portion 49 penetrating the thrust ring 20 and extending further downward.

The cavity 22 penetrating in the pipe axial direction from the upper end surface to the lower end surface of the fixed body 18 is provided with an enlarged portion 22a in the second portion 47 to the fourth portion 49 of the fixed body 18, and the enlarged portion 22a is formed in this enlarged portion 22a. A cooling medium guide structure 23 is arranged. The cooling medium guide structure 23 has, for example, a solid cylindrical shape,
A cooling passage is formed between the cooling medium guide structure 23 and the fixed body 18. For example, the upper and lower ends of the cavity 22 are opened to the outside of the vacuum container 11, and the cooling medium enters through the opening 222 at the upper end and the opening 22 at the lower end, for example, as indicated by an arrow Y.
The structure starts from 1.

Also in the case of the above-mentioned structure, for example, the joint portion 1
An enlarged portion 22a is formed in the cavity 22 surrounded by the joint surface P between the rotating body 17 and the rotating body 17, and the contact area between the heat of the anode target 12 transferred to the fixed body 18 and the cooling medium is increased to improve the heat dissipation effect. To do.

In the case of the embodiment of FIG. 4 as well, both ends of the fixed body 18 are fixed to the vacuum container 11. Therefore, the anode target 12 and the rotation support mechanism 14 are stably supported. Further, since the dynamic pressure type sliding bearings Ra, Rb, Sa and Sb are arranged on both sides of the anode target 12, the load balance applied to the upper and lower bearings is well balanced and a stable bearing function is realized.

In the embodiment shown in FIGS. 1 to 4, for example, the cavity 2 surrounded by the joint surface P between the joint portion 13 and the rotating body 17.
An enlarged portion 22a is formed in two parts. Then, the heat of the anode target is transferred to the rotating body 17 via the joint portion 13,
Further, it is transmitted to the fixed body 18. In this case, the enormous part 22
Since a is located near the heat transfer path to the fixed body 18, good heat dissipation is performed.

The anode target may be directly connected to the rotating body without using the joint portion. In this case, for example, it is desirable to form an enlarged portion in a cavity portion in a region surrounded by the connecting surface between the anode target and the rotating body or a region in the vicinity thereof including the region.

An embodiment of the present invention will be described with reference to the sectional view of FIG. In FIG. 5, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and overlapping description will be partially omitted.

In the case of this embodiment, the anode target 12
Is fixed to the joint portion 13 with a screw S4, and the joint portion 13 is the first
It is composed of a tubular portion 13a and a second tubular portion 13b having a large outer diameter.

The rotary body 17 constituting the rotary support mechanism 14 has a bottomed cylindrical shape, and is composed of a small diameter portion 51 and a large diameter portion 52 having an inner diameter larger than that of the small diameter portion 51. And
The inner surface of the second tubular portion 13b of the joint portion 13 is joined to the outer surface of the annular protruding portion 171 provided on the outer peripheral portion of the small diameter portion 51. The inner surface of the second tubular portion 13b of the joint portion 13 and the rotating body 1
A space 54 for heat insulation is formed between the outer surface 7 and the outer surface except the joint portion P located in the pipe axis m direction.

The opening at the lower end of the rotating body 17 in the figure is sealed with a thrust ring 20. The rotating body 17 and the thrust ring 20 are integrally fixed by, for example, a screw S5, and both of them constitute a rotating portion of the rotation supporting mechanism 14 together with the tubular rotor 19 and the like. Further, the fixed body 18 is fitted in the internal space surrounded by the rotating body 17 and the thrust ring 20 so as to have a slight gap during operation.

The fixed body 18 constitutes a fixed portion of the rotary support mechanism 14, and is fitted to the small diameter portion 51 of the rotary body 17 and has the small outer diameter 55 and the large diameter portion 52 of the rotary body 17. It is composed of a large-diameter portion 56 to be fitted, a second small-diameter portion 57 penetrating the portion of the thrust ring 20 and extending downward in the drawing. Rotating body 17 and thrust ring 20 and fixed body 1
The dynamic pressure type sliding bearing R in the radial direction is fitted to the mating part with 8.
a, Rb, and thrust type dynamic bearings Sa,
Sb is formed.

The first portion is provided outside the second small diameter portion 57 of the fixed body 18.
A trap T1 is provided. The first trap T1 is fixed to the rotating body 17 together with the thrust ring 20 with a screw S5. Further, a tubular sealing member 58 is joined to the outer peripheral surface of the second small diameter portion 57. The sealing member 58 is the fixed body 18.
Of the vacuum container 11 that hermetically seals the second trap T2. The first trap T1 and the second trap T2 capture the liquid metal lubricant that leaks from the fitting portion between the rotating portion and the fixed portion that configure the rotation support mechanism 14, and prevent it from leaking to the outside.

A cavity 22 is formed inside the fixed body 18 and extends along the tube axis m and is closed on the anode target 12 side. A cooling medium guide structure 23 is fitted on the inner side of the cavity 22, for example, on the anode target 12 side. The cooling medium guiding structure 23 is formed, for example, in a cylindrical shape, and the hole 2 through which the cooling medium rises, for example, in the direction of the arrow Y1 is formed in the central portion.
3a is formed, and the medium passage 2 in which the cooling medium descends in the direction of the arrow Y2 is formed between the fixed body 18 and the fixed body 18 located outside.
3b is formed.

A cylindrical support member 60 is inserted in the cavity 22 closer to the outside of the vacuum container 11 than the cooling medium guide structure 23. The cylindrical support member 60 has one end 60
a is located inside the vacuum container 11, and the other end 60b extends to the outside of the vacuum container 11. The end portion 60b located outside the vacuum container 11 is used as a support portion for fixing the rotary anode type X-ray tube in a storage container (not shown), and for example, a thread groove is formed on the outer peripheral surface. In this case, in consideration of thermal expansion, the cooling medium guide structure 23 and the support member 60 are provided.
And a small gap G is provided in the direction of the tube axis m.

Here, regarding the cooling medium guide structure 23,
This will be described with reference to FIG. 6 which is a cross section taken along line aa of FIG.
In FIG. 6, parts corresponding to those in FIG.

The cooling medium guide structure 23 is formed of a metal mainly composed of copper or a copper alloy, for example. A plurality of recessed grooves 61 extending parallel to the tube axis m are formed on the outer peripheral portion thereof, and a plurality of protrusions 62 are provided between adjacent recessed grooves 61.
Are formed. The recessed grooves 61 are formed, for example, so that opposed wall surfaces are parallel to each other and have a predetermined depth, and the plurality of protrusions 62 extend, for example, parallel to the tube axis m. Tip surface 6 of protrusion 62
2a has a predetermined width W along the circumferential direction of a circle centered on the tube axis m, and each tip surface 62a is located on a common cylindrical surface centered on the tube axis m. The tip surface 62a of the protruding portion 62 is fitted into the inner wall surface of the cavity 22 provided in the fixed body 18, and at the same time, is joined by, for example, diffusion bonding. At this time, a medium passage through which the cooling medium flows is formed in a region surrounded by the central hole 23a and the concave groove 61, for example, the region surrounded by the wall surfaces of the two adjacent protruding portions 62 and the inner wall surface of the cavity 22. It

Next, a method of joining the cooling medium guide structure 23 and the support member 60 to the inner surface of the cavity 22 of the fixed body 18 will be described. Iron alloy and molybdenum alloy (SKD11,
The inner surface of the cavity 22 of the fixed body 18 formed of TZM) and the outer surface of the support member 60 formed of SUS316 are plated with gold that functions as a diffusion promoting material. After that, the cooling medium guide structure 23 and the support member 60, which are made of a material mainly containing copper or copper alloy, are fitted into the cavity 22. In this state, in a hydrogen furnace or a vacuum furnace,
Heat treatment is performed at 50 ° C. for about 30 minutes or more.

At this time, for example, the protrusion 62, the support member 60, and the constituent elements of the inner surface portion of the cavity 22 diffuse into at least a part of the diffusion promoting material, and the protrusion 62 and the support member 60.
And the inner surface of the cavity 22 are diffusion-bonded. In this case, the cooling medium guiding structure 23 and the supporting member 60 have a larger coefficient of thermal expansion than, for example, at least the cavity 22 portion of the fixed body 18, so that the contact surfaces are brought into close contact with each other during heating and the pressure required for diffusion bonding acts. And good diffusion bonding is realized.

In the above structure, when the rotary anode type X-ray tube enters the operating state, the anode target 12 is heated by the collision of the electron beam. This heat passes through the joint portion 13 and the rotating body 1
Communicate to 7. Then, it is transmitted from the rotating body 17 to the fixed body 18 via the liquid metal lubricant. Further, the cooling medium is transmitted to the cooling medium guiding structure 23 and is discharged by the cooling medium flowing in the cavity 22 of the fixed body 18.

In the case of the above structure, the cooling medium guiding structure 2
3 is made of a metal having a high thermal conductivity, such as copper,
The tips of the plurality of protrusions 62 are in surface contact with the fixed body 18 mechanically and thermally. Therefore, the cooling medium guide structure 2
3 is heated in a wide range at a relatively uniform temperature. Also,
A plurality of protrusions 62 are formed on the outer peripheral portion of the cooling medium guide structure 23, and, for example, the cooling medium guide structure 23 and the cooling medium come into contact with each other over a wide area. Therefore, the effective contact area between the cooling medium guiding structure 23 and the fixed body 18 and the cooling medium is larger than that in the case of a simple pipe structure, the amount of heat transferred to the cooling medium is increased, and the heat dissipation characteristics are improved.

The inner diameter of the cavity 22 of the fixed body 18 is larger than the hole diameter of the support member 60. Therefore, the effective contact area between the fixed body 18 and the cooling medium flowing therein becomes large, and the amount of heat transferred to the cooling medium becomes large.

The support member 60 is made of a material having high strength such as SUS316, and at the same time, it is firmly bonded to the inner wall of the cavity 22. Therefore, the rotating anode type X-ray tube can be reliably fixed in the container by using the support member 60. In this case, since the supporting member 60 has a high strength and is firmly bonded to the inside of the cavity, the rotating anode X-ray tube can be reliably fixed even if the diameter of the fixing portion such as the supporting member 60 is reduced. Moreover, since the inner diameter of the cavity into which the cooling medium guide structure 23 is inserted can be increased, the effective contact area between heat and the cooling medium is increased, and the heat dissipation effect is enhanced.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to the sectional view of FIG. 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 this embodiment, the lower end 1 of the fixed body 18 in the drawing is shown.
8e extends to the outside of the vacuum container 11. Vacuum container 1
The portion of the fixed body 18 located outside 1 is used as a support portion for fixing inside the storage container for storing the rotary anode type X-ray tube, and for example, a thread groove is formed on the outer peripheral surface. in this case,
The tubular reinforcing member 71 is inserted into the cavity 22 at a position closer to the outside of the vacuum container 11 than the cooling medium guiding structure 23. The cylindrical reinforcing member 71 has a vacuum container 1 having one end 71a.
1, and the other end 71 b extends into the cavity 22 located outside the vacuum container 11. Also in this case, in consideration of thermal expansion, the cooling medium guide structure 23 and the cylindrical reinforcing member 71 are provided.
And a small gap G is provided in the direction of the tube axis m.

According to the above structure, the fixed body 18 is reinforced by the reinforcing member 71. Therefore, by using the fixed body 18 as the fixing portion, the rotating anode type X-ray tube can be reliably fixed in the container.

Next, FIG. 8 shows another embodiment of the present invention.
Will be described with reference to the sectional view of FIG. In FIG. 8, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and overlapping description will be partially omitted.

In the case of this embodiment, the first small diameter portion 181 of the fixed body 18 extends upward from the first thrust ring 32 by a predetermined length, and the second small diameter portion 182 extends from the second thrust ring 33 by a predetermined length. It only extends downward in the figure. Cavity 2
2 penetrates from the upper end to the lower end of the fixed body 18, and is formed to have the same inner diameter, for example.

Then, the cooling medium guide structure 23 is inserted into a part of the large-diameter portion 18a of the fixed body 18, for example, the cavity 22 in the region surrounded by the joint surface P between the bearing portion 13 and the rotating body 17, and the cooling medium is introduced. First and second support members 601 and 602 are inserted above and below the guide structure 23, respectively. First
The support member 601 includes the large-diameter portion 18a and the first small-diameter portion 181.
It is provided over the upper part of the vacuum container 11a and is extended to the upper part thereof and is fixed to the vacuum container 11a. The structure of the fixed portion of the first support member 601 and the vacuum container 11a is the same as that of the fixed body 18 of FIG.
It has the same structure as the fixed part of the vacuum container 11a.

The second support member 602 is provided so as to straddle the large-diameter portion 18a and the second small-diameter portion 182, extends further below it, and is hermetically fixed to the vacuum container 11b via the sealing member 21. There is. A lower end of the second small diameter portion 182, for example, a portion located outside the vacuum container 11b is used as a support portion for fixing the second small diameter portion 182 in the accommodating container of the rotary anode X-ray tube, and for example, a thread groove is formed on the outer peripheral surface. Has been done.

In the case of the above structure, the cooling medium guiding structure 2
3 and the first support member 601, the second support member 602,
Each is firmly bonded to the inner wall surface of the cavity 22 by diffusion bonding. In this case, the lower end of the first support member 601 in the drawing and the upper end of the second support member 602 in the drawing open to the outside of the vacuum container 11, and as shown by an arrow Y, for example, the cooling medium is guided from the first supporting member 601 to the cooling medium guiding structure. 23, a cooling passage that flows with the second support member 602 is formed.

Here, the cooling medium guide structure 23 of FIG. 8 will be described with reference to the sectional view of FIG. 9 taken along the line bb of FIG. In FIG. 9, parts corresponding to those in FIG. 8 are designated by the same reference numerals, and overlapping description is partially omitted.

The cooling medium guiding structure 23 is made of, for example, copper or a metal mainly composed of copper, and is solid, and a plurality of concave grooves 91 having a triangular cross section, for example, are formed on the outer peripheral portion thereof. The plurality of recessed grooves 91 extend, for example, parallel to the tube axis m, and a plurality of protruding portions 92 that extend, for example, parallel to the tube axis m are formed between adjacent recessed grooves 91. The tip surface 92a of each protrusion 92 has a predetermined width W in the radial direction of a circle centered on the tube axis m, and is located on a common cylindrical surface centered on the tube axis m, for example. . The tip surface 92a of the protruding portion 92 is fitted to the inner wall surface of the cavity 22 provided in the fixed body 18, and at the same time, joined by, for example, diffusion bonding. At this time, a medium passage through which the cooling medium flows is formed in a portion surrounded by the recessed groove 91, for example, the wall surface of the adjacent protruding portion 92 and the inner wall surface of the cavity 22.

The inner wall surface of the cavity 22 of the fixed body 18, the cooling medium guide structure 23 and the first and second support members 6 are provided.
The bonding with 01 and 602 is performed by the same method as in the embodiment of FIG. Also in this case, at least the cavity 22 of the fixed body 18 is formed of, for example, an iron alloy or molybdenum alloy, and the cooling medium guide structure 23 is formed of, for example, a metal material mainly containing copper or a copper alloy.

Also in the case of the above structure, a good heat dissipation effect can be obtained, and by using the supporting members 601 and 602 as the fixing portions, the rotating anode type X-ray tube can be surely fixed in the container.

In the embodiment shown in FIG. 8, two supporting members 601 and 602 located at both ends are fixed to the vacuum container 11. Therefore, the anode target 12 and the rotation support mechanism 1
4 is supported stably. Further, the dynamic pressure type sliding bearing Ra,
Rb, Sa, and Sb are arranged on both sides of the anode target 12. Therefore, the balance of the load applied to the upper and lower bearings is improved, and a stable bearing function is realized.

In the structure shown in FIGS. 5, 7, and 8,
When using alloy tool steel such as SKD11 for the fixed body,
It is necessary to prevent deformation due to baking during the heat treatment, and it is desirable to suppress the transformation point to a temperature not exceeding 800 ° C.

When diffusion bonding is used as described above, 7
Since the strong bonding can be achieved at a temperature of 50 ° C., the deformation of the SKD 11 is prevented.

In FIG. 5, FIG. 7 and FIG. 8, the cooling medium guide structure is formed of a material mainly composed of copper or a copper alloy. In this case, a material having a high thermal conductivity, for example, a material having a thermal conductivity of 100 W / mK or more at room temperature is desirable for the cooling medium guide structure.

Further, in FIG. 5, FIG. 7 and FIG. 8, the projecting portion of the cooling medium guiding structure is formed parallel to the tube axis, for example.
However, it is also possible to form the protrusion in a spiral shape extending in the tube axis direction.

Note that Au is used as a diffusion promoting material in the case of diffusion bonding. In addition to Au, Cu is used as the diffusion promoter.
A material selected from Pd, Pt, and alloys containing these metals can be used.

Further, for the supporting member and the reinforcing member which are inserted into the cavity together with the cooling medium guide structure, a material having a strength higher than that of the fixed body, for example, a material such as an iron alloy is effective.

In addition, in the case of FIGS. 5, 7 and 8, for example, the cooling medium guide structure is inserted in the cavity surrounded by the joint surface between the joint portion and the rotating body. In this case, the heat of the anode target is transferred to the rotating body through the joint, and when it is further transferred to the fixed body, the cooling medium guide structure is located near the heat transfer path, and good heat release is performed. .

The anode target can be directly connected to the rotating body without using the joint portion. In this case, for example, it is desirable to insert the cooling medium guide structure in the region surrounded by the connecting portion between the anode target and the rotating body and the hollow portion in the vicinity of the upper and lower sides in the tube axis direction.

According to the configuration of the invention as described above, the heat of the anode target can be efficiently transferred to the cooling medium flowing inside the fixed portion, and the outer shape of the fixed portion for fixing the rotary anode type X-ray tube can be improved. A rotating anode type X-ray tube having a large heat radiation effect is realized without increasing the size.

[0086]

According to the present invention, it is possible to realize a rotary anode type X-ray tube which can efficiently transfer the heat of the anode target to the cooling medium.

[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 cross-sectional view of a part of FIG. 5 taken along the horizontal direction.

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 cross-sectional view of a part of FIG. 8 taken along the horizontal direction.

[Explanation of symbols]

11 ... Vacuum container 12 ... Anode target 13 ... Joint 14 ... Rotation support mechanism 17 ... Rotating body 18 ... Fixed body 19 ... Cylindrical rotor 20 ... Thrust ring 21 ... Sealing member 22 ... Cavity 22a ... an enormous part of the cavity 23 ... Cooling medium guiding structure Ra, Rb ... radial dynamic bearings Sa, Sb ... Dynamic pressure type sliding bearing in thrust direction m ... tube axis

Claims (12)

[Claims] 1. An anode target that emits X-rays, and a dynamic pressure type sliding bearing using a liquid metal lubricant has a rotating portion and a fixed portion provided in a fitting portion, and rotatably supports the anode target. In a rotary anode type X-ray tube including a rotary support mechanism, a cavity through which a cooling medium flows is provided inside the fixed portion in the tube axial direction, and an enlarged portion having a large inner diameter is provided in a part of the cavity. A rotary anode type X-ray tube characterized in that 2. A cooling medium guide structure forming a passage through which a cooling medium flows between the cooling medium guide structure and the inner wall surface of the cavity is disposed in the cavity, and an outer diameter of the cooling medium guide structure is at an enlarged portion of the cavity. The rotating anode type X-ray tube according to claim 1, which is large. 3. The rotary anode type X-ray tube according to claim 2, wherein a hole through which the cooling medium flows is formed in the central portion of the cooling medium guide structure in the axial direction of the tube. 4. The rotation according to claim 1, wherein the enlarged portion of the cavity is provided in a portion surrounded by a rotation portion of a region mechanically connected to the anode target. Anode type X-ray tube. 5. The rotary anode type X according to claim 1, wherein a part of the fixed portion extends to the outside of the rotating portion, and an enlarged portion is provided inside the rotating portion.
Line tube. 6. An anode target arranged in a vacuum container, and a rotating portion which rotates integrally with the anode target,
A dynamic pressure type slide bearing is provided at a fitting portion with the rotating portion, which constitutes a rotation supporting mechanism for rotatably holding the anode target together with the rotating portion, and a fixed portion having a cavity therein. In the rotating anode type X-ray tube described above, a cooling medium guide structure for forming a passage for a cooling medium and a tubular support member are inserted into the cavity, and one end of the tubular support member is cooled by the cooling medium. A rotary anode X-ray tube, which is located closer to the outside of the vacuum container than the medium guiding structure, and has the other end extending to the outside of the vacuum container. 7. An anode target arranged in a vacuum container, and a rotating portion which rotates integrally with the anode target,
A dynamic pressure type slide bearing is provided in a fitting portion with the rotating portion, and constitutes a rotation supporting mechanism that rotatably holds the anode target together with the rotating portion, and a cavity is provided inside, and one end is In a rotating anode type X-ray tube having a fixed portion extending to the outside of a vacuum container, a cooling medium guiding structure for forming a passage for a cooling medium and a tubular reinforcing member are inserted into the cavity, and the reinforcing member is also provided. Has one end located closer to the outside of the vacuum container than the cooling medium guiding structure, and the other end extending into the cavity of the fixed portion located outside the vacuum container. A rotary anode type X-ray tube characterized by: 8. The cooling medium guiding structure according to claim 6, wherein a hole through which the cooling medium flows is formed in a central portion of the cooling medium guiding structure, and a pipe communicating with the hole of the cooling medium guiding structure is arranged inside the supporting member or the reinforcing member. Item 7. A rotating anode X-ray tube according to item 7. 9. The rotating anode type X-ray tube according to claim 6, wherein there is a gap between the cooling medium guide structure and the support member or between the cooling medium guide structure and the reinforcing member in the tube axial direction. 10. The diameter of the cooling medium passage portion formed in the cooling medium guide structure is such that the cooling medium passage portion formed in the support member portion or the cooling medium passage portion formed in the reinforcing member portion. The rotating anode type X-ray tube according to claim 6 or 7, which is larger than the diameter of the portion. 11. The cooling medium guiding structure according to claim 6, wherein a plurality of protrusions are formed on an outer peripheral portion of the cooling medium guiding structure, and tip ends of the plurality of protrusions are joined to an inner wall surface of the cavity. The rotating anode type X-ray tube described in 1. 12. The supporting member or the reinforcing member is made of a material having a thermal expansion coefficient larger than that of the material forming the fixed body,
The rotary anode X-ray tube according to claim 6 or 7, wherein an outer peripheral surface of the supporting member or the reinforcing member is diffusion bonded to an inner wall surface of the cavity.