Rotating X-ray anode with integrated liquid metal bearing housing

Abstract

The invention relates to a rotating X-ray anode with an integrated liquid metal bearing housing, comprising an anode disk (5) made of Mo or a Mo-based alloy and having a hole (12) formed in the region of the axis of rotation (4) and extending at least through a portion of the anode disk (5) in the axial direction, and a bushing (20) made of Mo or a Mo-based alloy. The bushing (20) is connected to the anode disk (5) by an integral joint (21), such that an inner wall (22) of the bushing (20) continues the hole (12) in the anode disk (5), and at least one axial section of the inner wall (14) of the hole (12) in the anode disk (5) and at least one axial section of the inner wall (22) of the bushing (20) are circumferentially formed as a liquid metal bearing running surface and form at least a portion of the liquid metal bearing housing. The invention also relates to a corresponding manufacturing method.

Description

Technical Field

[0001] The present invention relates to a rotating X-ray anode with an integrated liquid metal bearing housing, to a rotating X-ray anode system having a rotating X-ray anode with an integrated liquid metal bearing housing and a liquid metal bearing inner shell inserted therein, and to a manufacturing method for such a rotating X-ray anode. Background Art

[0002] Rotating X-ray anodes are used in X-ray tubes to generate X-rays. During use, electrons are emitted from the X-ray tube's cathode and accelerated as a focused electron beam onto the rotating X-ray anode. Due to the rotational motion of the rotating X-ray anode, the electron beam scans an annular trajectory, known as the focal trajectory. Most of the energy from the electron beam is converted into heat in the rotating X-ray anode, while a small portion is emitted as X-radiation. This localized heat release causes significant heating of the rotating X-ray anode. The rotation of the rotating X-ray anode counteracts overheating of the anode material.

[0003] Especially in the high-performance sector, high radiation power (or dose power) is required, which can be generated by using a correspondingly high-energy and highly focused electron beam. To avoid material fatigue caused by high temperatures and temperature gradients, rotating X-ray anodes must be designed for high-frequency rotation and for efficient and uniform heat dissipation. With these requirements in mind, the use of liquid metal bearings for mounting rotating X-ray anodes is advantageous.

[0004] US2016 / 0086760A1 and US2017 / 0125199A1 each disclose a rotating X-ray anode system in which a housing carrying liquid metal is inserted as an insert into a central channel hole of the rotating X-ray anode. US2016 / 0086760A1 also discloses a friction welding method using an intermediate component introduced into the weld zone. Other rotating X-ray anode systems are known from US5,204,890A and US6198805B1. Summary of the Invention

[0005] The object of the present invention is to improve the rotating X-ray anode with respect to good mounting and uniform and effective heat dissipation at high rotation frequencies. Furthermore, the rotating X-ray anode can be manufactured inexpensively in a stable process.

[0006] This object is achieved by the rotating X-ray anode, the rotating X-ray anode system and the method for producing a rotating X-ray anode according to the present invention. Advantageous developments of the present invention are described in further embodiments.

[0007] According to the present invention, a rotating X-ray anode with an integrated liquid metal bearing housing is provided. The rotating X-ray anode comprises an anode disk made of Mo (Mo) or a Mo-based alloy, a hole formed centrally in the region of the axis of rotation and extending axially through at least a portion of the anode disk, and a bushing made of Mo or a Mo-based alloy. The inner wall of the bushing is formed as a liquid metal bearing running surface circumferentially (i.e., in a circumferential direction relative to the axis of rotation) at least over an axial section thereof and forms a first subsection of the liquid metal bearing housing. More specifically, the entire (typically cylindrical) inner wall of the bushing can be formed as a liquid metal bearing running surface. Alternatively, only an axial section of the inner wall of the bushing can be formed as a liquid metal bearing running surface, this axial section then also typically being cylindrical, while another axial section can also comprise, for example, a mechanical boundary element and / or coating, by which the liquid metal is retained in the liquid metal bearing during use. The liquid metal bearing housing is formed from a first and an adjacent second subsection and has a continuous liquid metal bearing running surface. The bushing is connected to the anode disk by material bonding in such a way that the inner wall of the bushing continues the hole in the anode disk. Furthermore, at least one axial section of the inner wall of the hole in the anode disk is circumferentially (i.e., in a circumferential direction based on the axis of rotation) formed as a liquid metal bearing running surface and forms at least a part of the second subsection of the liquid metal bearing housing. Here, the entire (typically cylindrical) inner wall of the hole can also be circumferentially formed as the liquid metal bearing running surface. In the case of a blind hole, the bottom of the hole can optionally also form the liquid metal bearing running surface. Alternatively, only an axial section of the inner wall of the hole, which is then also typically cylindrical, can be circumferentially formed as the liquid metal bearing running surface.

[0008] In a liquid metal bearing, a defined bearing gap is formed between a matching liquid metal bearing outer shell and a liquid metal bearing inner shell, with one of the liquid metal bearing outer shell and the liquid metal bearing inner shell being formed on a fixed component, while the other of the liquid metal bearing inner shell is formed on a rotating component. In the present case, the liquid metal bearing outer shell is formed integrally with the rotating X-ray anode and thus serves as the rotating component. The liquid metal bearing inner shell can, for example, be integrally formed on a sleeve (fixed component) inserted into the liquid metal bearing outer shell. In use, the bearing gap is filled with liquid metal (e.g., gallium, a gallium alloy, such as a eutectic gallium-indium-tin alloy, etc.). The gap width typically ranges from a few micrometers to 500 μm (at least ≤ 1 mm), in particular 5-500 μm, preferably 7-40 μm, where the gap width can also vary over the length of the bearing gap. In particular, at least one circumferential cutout and / or step or ridge may be provided in the outer and / or inner shell of the liquidmetal bearing, in the region of which the gap width may also be formed to be different from the rest of the bearing gap (see, for example, DE 10 2015 21 5 306 A1). More particularly, at least one circumferential ridge may be provided on one component, while (at least) a correspondingly formed groove may be provided on the other component, for securing the two components relative to each other in the axial direction. The liquidmetal bearing running surface refers to a section of the liquidmetal bearing outer shell and the liquidmetal bearing inner shell that, during use, is wetted by liquidmetal on both the outer and inner shells, thereby enabling low-friction rotation. The liquidmetal prevents direct contact between the liquidmetal bearing outer shell and the liquidmetal bearing inner shell, while also acting as a lubricant, which results in excellent running characteristics. To drive the rotating X-ray anode, the liquidmetal bearing outer shell is provided with a rotor or is (mechanically) coupled to a rotor, which is arranged to rotate in interaction with a stator in a known manner.

[0009] The use of liquid metal bearings for mounting rotating X-ray anodes is advantageous because they are designed for high loads and high rotational frequencies while also offering high operational reliability and a long lifespan. One advantage (e.g., compared to ball bearings) is that the increased pressure of the liquid metal present in the bearing gap is exerted over a larger portion of this area (particularly in the axial direction), thereby increasing mechanical stability. More specifically, with liquid metal bearings, rotational frequencies of up to 300 Hz (Hertz) are possible, whereas ball bearings, for example, are typically designed for rotational frequencies well below 200 Hz (e.g., 140 Hz). Furthermore, compared to ball bearings, liquid metal bearings exhibit low noise levels and, due to the increased contact area (via the liquid metal-filled bearing gap), enable efficient heat dissipation over a large area. Heat can thus be effectively dissipated to a stationary component (e.g., to a sleeve inserted into the housing of the liquid metal bearing on the inside). The heat can then be effectively removed from the stationary component via internal cooling (using a coolant conducted within at least one cooling channel), making thermal management very efficient and therefore suitable for high-performance applications. In contrast, due to the use of heat-sensitive coatings, ball bearings are not designed for efficient heat dissipation through the bearing, as this would lead to damage to the respective coating.

[0010] Mo or a Mo-based alloy is particularly advantageous as a material for the anode disk and for the bushing, as they have high strength (even at high operating temperatures) and enable good heat dissipation. In addition, Mo or a Mo-based alloy has good wettability with the liquid metals commonly used. Therefore, it is also advantageous to form the inner wall of the bushing and the inner wall of the hole in the anode disk as a liquid metal bearing running surface, because even the substrate thus produces good wettability. Optionally, a coating (typically less than 10 μm thick) can be provided on the inner wall of the bushing and / or on the inner wall of the hole, in each case completely or only in sections. However, instead of providing a separate insert with a liquid metal bearing housing inside, this housing would have to be inserted into the hole in the anode disk and bonded thereto, which would be more complicated in terms of manufacturing and could constitute a barrier to heat dissipation. In addition, a high mechanical stability is achieved between the anode disk and the liquid metal bearing housing, which is beneficial for the running characteristics. Since the inner wall of the bushing continues the inner wall of the hole in the anode disk and thus provides a liquid metal bearing running surface with a correspondingly long axial extent, this ensures mechanical stability and precise guidance of the anode disk during rotation.

[0011] In this document, a Mo-based alloy refers to an alloy containing >50% by weight Mo. In particular, it contains ≥80% by weight Mo, more preferably ≥98% by weight, which is particularly advantageous for the aforementioned properties of Mo. The anode disk and bushing do not necessarily consist entirely of Mo or a Mo-based alloy; rather, the substrate is specifically referred to. In particular, they may be provided with a coating (e.g., a blackened layer to increase the emitted heat output), a mating component, such as a C substrate (e.g., a graphite body) fixed to the anode disk as a heat storage device, a flange mounted on the bushing, or a coating, such as a circumferential focal track coating applied in the focal track region. As explained at the outset, "focal track" refers here to the circumferential section of the anode disk that forms a ring around the axis of rotation and is scanned by the electron beam during use. Typically, a focal track coating is applied to the anode disk in the region of the focal track (within a certain radial extent). The focal track coating is particularly formed from W or a W-Re alloy (W: tungsten; Re: rhenium) with a Re content of 1-15% by weight, in particular 5-10% by weight. Furthermore, the anode disk typically has an angled focal track surface in the region of the focal track, which preferably forms a circumferentially frustoconical shell surface. More particularly, the focal track surface is angled relative to a reference plane extending at right angles to the axis of rotation, which enables the generated X-ray radiation to exit through a lateral exit window in a corresponding X-ray device. For example, it forms a focal track angle relative to this reference plane in the range of 2°-16.25°, in particular in the range of 7°-13°.

[0012] The "axis of rotation" referred to is defined by the rotationally symmetrical basic shape of the rotating X-ray anode and the liquid metal bearing housing. The axis of rotation simultaneously defines an "axial direction" (which extends parallel to the axis) and a "radial direction" (which extends at right angles to the axis). The "reference plane" of the rotating X-ray anode (which generally also forms its main extension plane) extends, in particular, perpendicular to the axis of rotation. It should be noted that the rotating X-ray anode does not need to be precisely rotationally symmetrical in every detail, so that, for example, the periodic arrangement of slits, protrusions, recesses, mating components, etc. formed in the circumferential direction can disrupt the exact rotational symmetry. A bushing is a component having a (channel) hole, in this context, whose inner wall at least partially forms the liquid metal bearing running surface, wherein the bushing can have different profiles (especially outer shapes) and mating components. In a preferred variant, the bushing (and accordingly, the mechanical mounting of the rotating X-ray anode) is arranged on the side of the anode disk opposite the focal track. Alternatively, the bushing (and accordingly, the mechanical mounting of the rotating X-ray anode) can also be arranged on the side of the anode disk on which the focal track is provided.

[0013] According to the invention, a first subsection of the liquid metal bearing housing is formed integrally with the bushing, and at least a portion of the second subsection of the liquid metal bearing housing is formed integrally with the anode disk. "Integrally" here means that the component in question is produced in a single piece by metallurgical production (preferably by powder metallurgy or alternatively by melt metallurgy), with the possibility of subsequent mechanical processing, for example for the introduction of holes and / or surface structuring, and / or the subsequent application of at least one layer. The integral production is obvious to a person skilled in the art from a uniform and constant microstructure (of a substrate consisting of Mo or a Mo-based alloy). The anode disk and / or the bushing are preferably produced by powder metallurgy, wherein this includes the steps of pressing and sintering the corresponding starting powders and preferably subsequently forming the resulting shaped body (e.g., rolling, forging, extrusion, etc.). Production by powder metallurgy results in a typical microstructure that is obvious to a person skilled in the art and that, for example, differs significantly from a melt microstructure (obtained in production by melt metallurgy). Thus, the inner wall of the bushing, at least in the region of the liquid metal bearing running surface, is formed by the base material of the bushing (Mo or a Mo-based alloy), and the inner wall of the hole in the anode disk, at least in the region of the liquid metal bearing running surface, is formed by the base material of the anode disk (Mo or a Mo-based alloy). A coating (typically with a thickness of less than 10 μm) and / or a surface structure may also be provided on the inner wall of the bushing and / or the inner wall of the hole in the anode disk.

[0014] A materially bonded connection is understood to mean that a continuous material bond is produced, but not that there is only a mechanical connection (e.g., a connection via screws or clamps, via mechanical fixing elements, etc.). More particularly, the materially bonded connection of the bushing and the anode disk is established by welding, by brazing, or by diffusion bonding (diffusion bonding). If the bonded areas are examined microscopically in cross-section, a weld bond is apparent to a person skilled in the art by virtue of the corresponding weld zone (molten or at least plasticized base material), a solder bond by virtue of the corresponding brazing zone (molten structure of the solder), and a diffusion bond by virtue of the corresponding diffusion zone (diffusion zones of the base materials bonded to one another).

[0015] The formation of a liquid metal bearing outer shell is obvious to a person skilled in the art from the shaping, in particular from the liquid metal bearing running surface formed on the inside in a rotationally symmetrical manner with respect to the axis of rotation, and from the inner contour that enables the introduction of a sleeve (or other type of component) with a corresponding liquid metal bearing inner shell. Furthermore, no running grooves for ball bearings are provided on the inner contour (even though the liquid metal bearing running surface can, in principle, be graduated and / or provided with ridges or cutouts). Optionally, surface structures, coatings, and / or mechanical boundary elements are provided in the region of the end sections of the liquid metal bearing outer shell and / or the liquid metal bearing inner shell to retain the liquid metal in the region of the liquid metal bearing.

[0016] In one refinement, the material-bonding connection is a bond produced via diffusion bonding, friction welding, or beam welding (using a laser or electron beam). The aforementioned bonding techniques have the advantage that they can be used to achieve a material-bonding connection with high strength even at high operating temperatures. More particularly, in the region of the bonding zone, any added materials (e.g., solder, filler materials, etc.) can be omitted, which could form troublesome impurities in the region of the liquid metal bearing (e.g., in the liquid metal), could be critical for vacuum stability (for use under high vacuum), and / or could have a lower melting point (compared to the base materials of the joined components). This is particularly advantageous compared to solder bonds, in which the solder typically has a lower melting point than the base material (of the joined components) and, at least at high temperatures, has a lower strength than the base material (of the joined components).

[0017] In diffusion bonding, the (usually suitably prepared) surfaces of the components to be joined are brought together, and the application of pressure and temperature causes diffusion of atoms in the region of the bonding zone to produce a material-bonded connection (diffusion bonding). According to the (narrower) understanding of diffusion bonding that underlies this, no melting of the base materials of the components to be joined occurs in the region of the bonding zone. As described above, diffusion bonding is readily apparent to a person skilled in the art through microscopic analysis of the bonding zone in microscopic sections, where no molten microstructures are present in the respective diffusion zones (diffusion zones of the mutually bonded base materials). If components made of the same material are bonded together by diffusion bonding, diffusion bonding may not be apparent in microscopic sections because a uniform microstructure that is constant relative to the specific base materials can be achieved in the region of the bonding zone. In these cases, the presence of diffusion bonding can be derived solely from the outward geometry of the bonded components (in this case, the anode disk and the bushing), for example because they cannot be manufactured in a single piece (e.g., by powder metallurgy) with a corresponding overall shape. Beam welding is readily apparent to those skilled in the art through microscopic analysis of the bond zone in microsections, the weld zone in which the corresponding molten microstructure (of the base material and any additional filler material) is present, and the root and location of the molten zone. Beam welding, particularly by electron beam welding, is advantageous due to the small heat-affected zone. Furthermore, this beam welding method is more suitable for Mo-based alloys than for pure Mo.

[0018] In friction welding, a component is moved relative to and brought into contact with (e.g., rotated) the other component to be joined, generating heat at the adjoining surfaces. Welding is accomplished by applying force during or after cessation of the relative motion (e.g., rotational motion). Various energy supply and relative motion methods exist. In the present case, the joining occurs between largely rotationally symmetrical components, with one component (e.g., a bushing or stub) being rotated and then brought into contact with the other component (e.g., an anode disk) to generate frictional heat. Friction welding also enables the joining of components with relatively high wall thicknesses (particularly 20-130 mm), resulting in relatively low joining temperatures only in the joint cross-section. Therefore, in many cases, it is suitable for materials and material combinations that would otherwise be difficult to weld (see also DIN EN ISO 15620 in this regard). This is particularly true for pure Mo and Mo-based alloys. The typical microstructure of friction welded bonds is readily apparent to those skilled in the art through microscopic analysis of the bond zone in microsections. More specifically, since the substrates are only plasticized during the friction welding process, there is no discernible molten microstructure. Typically, the weld zone is relatively narrow and has a fine-grained microstructure. Specifically, in the case of a friction welded connection of a liner and an anode disk, multiple weld zones (between the liner's base material and the anode disk) with slightly different microstructures are evident in the region of the weld zone, wherein each of the liner and the anode disk is formed from Mo and / or a Mo-based alloy. More specifically, the present invention relates to grain size distribution and grain arrangement. Generally, the grains extend in the direction of material flow, which occurs particularly during weld bead formation. In particular, when the liner has a high grain elongation and the anode disk has a lower grain elongation, regions of differing grain elongation (high grain elongation near the liner and lower grain elongation near the anode disk) appear, as evidenced by their respective manufacturing methods. Furthermore, a macroscopic indicator of a friction welded connection is when a protruding connection port is used on the anode disk to enable weld bead formation during friction welding (due to material flow during the compression phase). This is particularly evident in the weld zone between the connection port and the liner, which is spaced apart from the anode disk.

[0019] In one refinement, the Mo-based alloy (of the anode disk and / or bushing) is MHC and / or TZM. More particularly, the base material of the bushing (i.e., excluding coatings, mounting components, etc.) is made of MHC and / or TZM (preferably, exclusively MHC or exclusively TZM). Even more particularly, the base material of the anode disk (i.e., excluding coatings, mounting components, etc.) is made of MHC and / or TZM (preferably, exclusively MHC or exclusively TZM). Both alloys (MHC, TZM) have high strength and hardness. Their mechanical properties remain essentially unchanged at high temperatures, which enables higher process temperatures during manufacturing and, consequently, higher operating temperatures for the rotating X-ray anode. This is particularly true for MHC at temperatures up to 1250°C and for TZM at temperatures up to 1100°C. MHC is therefore particularly well-suited for high-performance applications and high operating temperatures.

[0020] MHC is a Mo-based alloy provided by the applicant Plancy Co., Ltd. and has the following composition:

[0021] -Hf content is 1.00-1.30% by weight,

[0022] -C content is 500-1200μg / g (μg: microgram),

[0023] Balance: Mo (generally ≥97.0% by weight, preferably ≥98.0% by weight, wherein the Mo content with correspondingly low impurity proportions can even be ≥98.5% by weight).

[0024] TZM is a Mo-based alloy specified in standard ASTM B387 (364) and provided by the applicant Plansi GmbH, having the following composition used in the present application:

[0025] -Ti content of 0.40-0.55% by weight

[0026] -Zr content is 0.06 to 0.12% by weight,

[0027] - C content of 50-500 μg / g, wherein this range (which is particularly well suited for the field of application of rotating X-ray anodes) is much higher than that of standard ASTM B387

[0028] The range of 100–400 μg / g specified in (364) is slightly wider.

[0029] Balance: Mo (generally ≥98.0% by weight, preferably ≥99.0% by weight, wherein the Mo content with correspondingly low impurity proportions can even be ≥99.3% by weight).

[0030] The permissible / allowable content of any impurities that may be present is generally not specified for all elements, but rather specifically for those elements that are typically present and / or for which excessively high content would be critical for the alloy's advantageous properties. In this context, the following permissible impurity ranges are particularly advantageous: in particular, the total content of metallic impurities in MHC and TZM is ≤ 5000 μg / g. In particular, in the case of MHC and TZM, according to Plansi GmbH's particularly advantageous specifications, the content of each of Al (aluminum) and Ni (nickel) is ≤ 10 μg / g, the content of each of Cr (chromium), Cu (copper), Fe (iron), K (potassium), and Si (silicon) is ≤ 20 μg / g, the content of W (tungsten) is ≤ 300 μg / g, the content of each of Cd (cadmium) and Pb (lead) is ≤ 5 μg / g, and the content of Hg (mercury) is ≤ 1 μg / g. The total content of any H (hydrogen), N (nitrogen), and O (oxygen) impurities that may be present in MHC and TZM is ≤ 1000 μg / g. In particular, in MHC according to the Plansi GmbH specifications, the content of each of H and N is ≤ 10 μg / g, and the content of O is ≤ 600 μg / g. The total content of any H, N, O, and C (carbon) impurities that may be present in TZM is ≤ 1500 μg / g. In particular, in TZM according to the Plansi GmbH specifications, the content of each of H and N is ≤ 10 μg / g, and the content of O is ≤ 500 μg / g. Depending on the manufacturing process, Cr(VI) and organic impurities are possible and acceptable, with a maximum of ≤ 1000 μg / g; these are generally undetectable in alloys supplied by Plansi GmbH. The sum of all impurities, S, in MHC and TZM should preferably be within the range of 0 ≤ S ≤ 6000 μg / g, with W (tungsten) as a typical impurity preferably accounting for ≤ 300 μg / g.

[0031] In principle, the anode disk and the bushing can be made of different materials. In one refinement, both the anode disk and the bushing are formed from molybdenum or the same molybdenum-based alloy. This is particularly advantageous for material-to-material connections (particularly in the case of friction welded or beam welded connections) due to the identical material properties of the two components (e.g., both made from MHC or both made from TZM). As is clear to those skilled in the art, molybdenum-based alloys are considered identical even if there are minor differences in composition. In particular, only "slight differences" exist when both compositions are within the specification range for the Mo-based alloy in question (e.g., for TZM or MHC specified above). If there are no specifications for the alloy in question, only "slight differences" typically exist even when the Mo content differs by ≤2 wt%. Differences in non-metallic alloying components (e.g., C, N) total ≤0.2 wt%, differences in any metallic alloying components present total ≤1 wt%, and differences in W ≤0.05 wt% (for impurities, the ranges specified above for TZM and MHC apply in particular).

[0032] In one refinement, the material-bonding connection is a friction welding connection. This is advantageous for achieving high bond strength and thermal stability. Furthermore, friction welding technology offers high reproducibility and a high level of automation. In friction welding, any added materials (e.g., filler materials, inserts introduced between the components to be joined, etc.) are preferably omitted, meaning that essentially no foreign material is present besides the base materials of the components to be joined, and essentially no detectable differences in composition are present in the region of the material-bonding connection. In friction welding, Mo-based alloys are preferred over pure Mo. Even more preferably, both components (anode disk, bushing) are formed from the same Mo-based alloy (e.g., both from MHC, both from TZM, etc.), as this allows for particularly high stability and quality of the friction welded connection. A particular advantage of friction welding (compared to beam welding methods, for example) is that no melt forms in the joining zone; rather, the base materials of the components to be joined are merely plasticized. This creates a favorable microstructure in the joining zone and maintains a uniform distribution of the elements / compounds present (e.g., in Mo-based alloys).

[0033] In one refinement, the anode disk has a connection port on the side facing the bushing, the inner wall of which extends beyond the hole in the anode disk and projects relative to the peripheral surface on the outer side of the anode disk. At least one axial section of the inner wall of the connection port is formed in this circumferential direction as a liquid metal bearing running surface and forms (along with the inner wall and any further sections of the hole in the anode disk) a portion of a second subsection of the liquid metal bearing housing. Furthermore, a materially bonded connection is formed between the protruding connection port of the anode disk and the bushing. The protruding connection port, which can in particular have a tubular or hollow cylindrical basic form, makes it easier to establish a material bond between the anode disk and the bushing. This is particularly true in the case of friction welding (but also in the case of beam welding), as this essentially provides two identical sections (in particular having a circumferential wall and annular end faces) to be joined together. Consequently, the materially bonded connection is also spaced apart from the peripheral surface on the outer side of the anode disk by, for example, 2-50 mm, preferably 5-30 mm (a range applicable to the completed material bond). This creates sufficient space for the formation of the weld bead, which is formed by the flow of material during the compression phase, especially in the case of friction welding. (The weld bead is subsequently removed by further processing.) Since compression is achieved during friction welding, the initial axial length of the connection port (before the material bond is established), especially when using a friction welding process, should be selected so as to be longer than the later desired position of the material bond, for example 3-8 mm longer. The connection port is preferably formed integrally with the anode disk, which is advantageous in terms of stability and operating characteristics. Preferably, the connection port is formed integrally from the material of the anode disk during the forging process. Alternatively, it can also be materially bonded to the anode disk.

[0034] In a refinement, the hole in the anode disk is in the form of a through-hole, and the anode disk has an extension port on a side opposite the bushing, the inner wall of the extension port extending the through-hole of the anode disk and projecting relative to a peripheral surface on the outer side of the anode disk. At least one axial section of the inner wall of the extension port is formed in this circumferential direction as the liquid metal bearing running surface and forms (in addition to the inner wall of the hole in the anode disk, optionally forming the connection port and any further sections) a portion of the second subsection of the liquid metal bearing housing. Providing such an extension port is advantageous for the stability and operating characteristics of the liquid metal bearing housing (in particular, because extensions of the liquid metal bearing running surface are then provided on either side of the anode disk). In a manner corresponding to the case of the connection port, the extension port is preferably formed integrally with the anode disk (e.g., by forging), or alternatively, it is possible for it to be materially bonded to the anode disk. Preferably, the extension port and any other components present then form the entirety of the liquid metal bearing housing. Alternatively, depending on the configuration of the liquid metal bearing, it is also possible to bond another bearing material to the extension port and thus extend the liquid metal bearing housing still further, and the variations described here for bonding the connection port to the bushing are likewise possible.

[0035] In one refinement, the thickness of the anode disk (measured in the axial direction) increases in the radial direction toward the axis of rotation. This increase in thickness can be continuous (with a constant slope or with a varying thickness profile) or in one or more stages. Thus, the heat generated in the region of the focal track can be distributed over a gradually increasing material cross section toward the axis of rotation and then effectively removed over a large area of ​​the liquid metal bearing outer shell (via the liquid metal disposed in the bearing gap and then via the liquid metal bearing inner shell and adjacent components, such as via a coolant-cooled sleeve). This increase in the material cross section in the radially inward direction avoids temperature spikes and excessive temperatures occurring locally in the region of the liquid metal bearing, which could cause damage to the liquid metal bearing and stresses in the anode disk. In one refinement, the thickness increase in the region of the hole, starting from a reference thickness measured radially midway in the region of the inclined focal track, is 30-300%, in particular 50-260%, even more preferably 70-230% (a 100% increase in thickness corresponds to a doubling of the thickness). This is particularly advantageous with regard to heat dissipation and the stability and operating characteristics of the liquid metal bearing housing. "Thickness in the area of ​​the hole" refers to the thickness of the anode disk directly in the area of ​​the inner wall of the hole, and this thickness measurement also includes any sections formed integrally with the anode disk, such as an integral connection port and / or an integral extension port, rather than components that are only materially bonded to the anode disk (such as a bushing). However, preferably, the anode disk increases in thickness in the radially inward direction, excluding any integral connection port and / or extension port. In particular, where such an integral connection port and / or extension port is provided, a reference area directly (radially) outside the connection port and / or extension port is used instead of the "area of ​​the hole", the latter having a thickness increase of 20-150%, preferably 30-100%.

[0036] In one refinement, the anode disk has a plurality of slits that are uniformly arranged around the circumference and extend through the thickness of the anode disk, each of these slits extending over a radial section in the region between the outer circumference of the anode disk and the hole in the anode disk. During use at the high temperatures encountered, these slits enable the material of the anode disk to expand without plastic deformation, which avoids stresses within the material and, therefore, material fatigue or failure. The slits can extend precisely radially. Alternatively, they can also extend slightly obliquely relative to the radial direction (e.g., at an angle of >0° up to 5°). The radial direction, the axial direction (here also, they can extend slightly obliquely relative to the axial direction, e.g., at an angle in the range of 1°-10°), and / or the width of the slits can vary according to a defined profile. Furthermore, at least one end of the slits (preferably the radially inner end) can also be provided with a terminal hole that preferably extends through the thickness of the anode disk, with each terminal hole having a diameter greater than the width of the opening slit and / or the circumferential groove. Preferably, the slits extend all the way to the outer circumference, i.e., open onto the outer circumference, while they terminate radially outside the hole in the anode disk. Preferably, all slits are formed symmetrically relative to one another with respect to the axis of rotation. Providing such slits is advantageous, in particular, when the thickness of the anode disk increases towards the axis of rotation.

[0037] The present invention further relates to a rotating X-ray anode system comprising a rotating X-ray anode according to the invention with an integrated liquid metal bearing outer shell, which can optionally also be formed according to one or more of the above-mentioned refinements, and a liquid metal bearing inner shell which has been inserted into the liquid metal bearing outer shell and has a liquid metal bearing running surface, wherein the liquid metal bearing outer shell and the liquid metal bearing inner shell are matched to each other so that a defined bearing gap (gap width, in particular as described above) is formed between them.

[0038] In one refinement, at least one circumferential mechanical boundary element is provided in the region of at least one axial end section (axial: relative to the axis of rotation) of the liquid metal bearing running surface on the liquid metal bearing outer shell and / or the liquid metal bearing running surface on the liquid metal bearing inner shell. This boundary element, during use, limits the flow of liquid metal present in the bearing gap in the axial direction. The mechanical boundary element thus serves to retain the liquid metal in the (axially) inner region of the liquid metal bearing, in which region a lubricating effect is to be achieved. The mechanical boundary element can, in particular, be formed by one or more of the following variants:

[0039] - a continuation of the bearing gap formed by multiple stages for forming a labyrinth seal (see, for example, JP 2012 / 084400 A);

[0040] One or more circumferential (constant or interrupted by short sections in the circumferential direction) ridges on one (e.g., stationary, inner) part of the liquid metal bearing and corresponding grooves on the other (e.g., rotating, outer) part of the liquid metal bearing, thereby simultaneously also providing axial fixing of the liquid metal bearing; in the case of a plurality of ridges, these can also be arranged alternately on one and the other part;

[0041] Backing rings made of a material that interacts with the liquid metal present in the bearing gap, for example an alloy containing iron, nickel and cobalt (see, for example, DE 102015204488 A1).

[0042] In one refinement, a circumferential coating is provided in the region of at least one axial end section of the liquid metal bearing running surface on the liquid metal bearing outer shell and / or the liquid metal bearing running surface on the liquid metal bearing inner shell, which inhibits wetting of the liquid metal in the bearing gap during use. This keeps the liquid metal in the (axial) inner region of the liquid metal bearing, where lubrication is desired. Suitable coatings include titanium oxide, aluminum oxide, titanium nitride, and mixtures thereof, in particular CrN (chromium nitride), Cr2N (chromium nitride), Cr2O3 (chromium(III) oxide), TiAlN (titanium aluminum nitride) (see, for example, US 2017 / 0169984 A1). The coating can be provided on both the liquid metal bearing inner shell and the liquid metal bearing outer shell. However, if appropriate, it can also be provided separately on a housing (for example, separately on the liquid metal bearing inner shell). Furthermore, it can also be provided in the region of at least one mechanical boundary element.

[0043] In one refinement, the liquid metal bearing inner shell is formed on a sleeve that is guided through the bushing at least into the hole in the anode disk. Preferably, the sleeve has at least one coolant duct for guiding the coolant. If the hole is formed as a passage hole, the sleeve preferably also extends completely through the passage hole. The sleeve is preferably formed from a single component (in a single piece), as this is advantageous with regard to its stability and the leak-proofing of the coolant duct. Alternatively, it can also be formed from multiple components that are joined to one another in a form-fitting and / or materially bonded manner, which can be particularly advantageous in the case of complex designs of the liquid metal bearing. The at least one coolant duct, which preferably extends over at least 80% of the length of the sleeve, allows for efficient heat removal during use.

[0044] In one refinement, the liquid metal bearing running surface on the outer liquid metal bearing shell and / or the liquid metal bearing running surface on the inner liquid metal bearing shell has at least two circumferentially structured running surfaces spaced axially from one another. Preferably, at least one unstructured section is provided between the at least two structured running sections. In the area of ​​the structured running sections, liquid metal accumulates during use as the rotating component rotates and builds up an increased pressure. This achieves a particularly good lubrication effect. Simultaneously, the rotating and stationary components are secured radially relative to one another. Providing at least two such running sections also prevents tilting and vibration of the rotating X-ray anode during use. It is particularly advantageous if the structured running sections are formed in a region located completely within the anode disk or at least overlap this region. The surface structuring can take the form of, for example, a groove pattern (e.g., having one or more subregions, each with grooves extending parallel to one another). The structured running sections can, in principle, be provided on both the inner and outer liquid metal bearing shells. In principle, the structured running sections can also be formed opposite one another (based on the bearing clearance). However, it is preferred that in the region of a surface-structured running section of one component (for example on a liquid metal bearing inner shell), the other component in the opposite region does not have a surface-structured running section.

[0045] The present invention also relates to a method for producing a rotating X-ray anode according to the invention, which can optionally also be formed according to one or more of the above-mentioned refinements and variants, wherein the method comprises the following steps:

[0046] Providing an anode disk made of Mo or a Mo-based alloy,

[0047] Provide short columns made of Mo or Mo-based alloys,

[0048] - bonding the stub to the anode disk material so that the stub is centrally arranged based on the axis of rotation of the anode disk, and

[0049] ● Mechanically processing the anode disk and the stub to form a rotating X-ray anode with an integrated liquid metal bearing housing, wherein the stub forms a bushing with a liquid metal bearing running surface, and the anode disk has a hole in which at least one axial section of the inner wall is circumferentially formed as a liquid metal bearing running surface.

[0050] The method establishes an inexpensive and reliable manufacturing route for manufacturing the rotating X-ray anode of the invention. Furthermore, by providing corresponding method steps, the above-mentioned improvements and variants are also possible in the method of the invention and the above-mentioned advantages are achieved.

[0051] The anode disk and / or stub are preferably produced by powder metallurgy. This includes, in particular, pressing and sintering of the corresponding starting powders, and preferably also forming (e.g., rolling, forging, round rolling, round forging, etc.). Prior to material bonding, the holes in the anode disk and / or the passage holes in the bushing may already be pre-formed, which makes further mechanical processing less complicated. Alternatively, they can also be elaborated in a machining operation (i.e., the anode disk and / or stub still have no holes or passage holes prior to material bonding). Material bonding is preferably achieved by friction welding. Prior to material bonding, the focal track coating may have already been applied to the anode disk (e.g., by powder metallurgy production in a composite material), but it can also be applied subsequently, for example, by thermal spraying (e.g., vacuum plasma spraying), chemical vapor deposition (CVD), or physical vapor deposition (PVD). Other mating components, coatings, coverings, etc., as already mentioned above, may also be added during the manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Other advantages and advantages of the present invention will become apparent from the following description of working examples, with reference to the accompanying drawings.

[0053] The accompanying drawings show:

[0054] Figure 1 : A cross-sectional perspective view of a rotating X-ray anode of the present invention according to a first embodiment;

[0055] Figure 2A 、 2B : Figure 1 Two cross-sectional views of the rotating X-ray anode in Figure 1, used to illustrate the fabrication;

[0056] Figure 3 : A cross-sectional view of a rotating X-ray anode of the present invention according to a second embodiment;

[0057] Figure 4 : A cross-sectional view of a rotating X-ray anode of the present invention according to a third embodiment;

[0058] Figure 5 : A cross-sectional view of a rotating X-ray anode according to a fourth embodiment of the present invention;

[0059] Figure 6 : A cross-sectional view of a rotating X-ray anode of the present invention according to a fifth embodiment;

[0060] Figure 7 : A cross-sectional view of a rotating X-ray anode according to a sixth embodiment of the present invention;

[0061] Figure 8 : a cross-sectional view of a rotating X-ray anode of the present invention according to a seventh embodiment; and

[0062] Figure 9 : Cross-sectional view of a rotating X-ray anode system of the invention with an inserted sleeve, showing two variants A and B of the sleeve above the cross-sectional view, each variant being shown once in the top view and once in the cross-sectional view. DETAILED DESCRIPTION

[0063] Figure 1-9 The diagram is a schematic diagram without exact reproduction of the dimensional ratios and does not show details of the liquid metal bearing housing and the axial terminations of the liquid metal bearing. As is known in the art, different configurations are possible for the axial terminations of the liquid metal bearing, examples of which include those shown in DE 102015204488 A1, US 2016 / 0086760 A1, US 5,204,890 A, JP 2012 / 084400 A and US 2017 / 0169984 A1. In other words, in Figure 1-9 In the figures, the bushing, the anode disk and the casing may be further continued in the axial direction, may have a different number of stages or a different configuration, and / or may be connected to further components.

[0064] Reference below Figure 1 and 2A 2B illustrates a first embodiment of a rotating X-ray anode 2 according to the present invention. In its basic form, it comprises an anode disk 5 made of MHC, formed in a rotationally symmetrical manner relative to the axis of rotation 4 (axially). On one side of the anode disk 5 is a circumferential focal track 6 having a focal track coating of a W—Re alloy (W: 95 wt. %; Re: 5 wt. %). In the region of the focal track 6, the anode disk 5 has a circumferentially inclined focal track surface 10, which is angled (at an angle α) relative to a reference plane 8 extending at right angles to the axis of rotation 4. A hole 12 extends through the anode disk 5, the inner wall 14 of which is formed as a liquid metal bearing running surface. On the opposite side of the focal track 6, the anode disk has an integral tubular connection port 16, which is attached by forging and is made of the material of the anode disk 5 and projects relative to the peripheral surface on the outer side of the anode disk 5. Its inner wall 18 extends the hole 12 in the anode disk 5 and also takes the form of a liquid metal bearing running surface. A tubular bushing 20, also formed from MHC, is bonded via its axial (annular) end face to a correspondingly formed axial (annular) end face of the connection port 16 via a material bond 21. An inner wall 22 of the bushing 20 is formed circumferentially as a liquid metal bearing running surface. The anode disk 5, the connection port 16, and the liquid metal bearing running surface of the bushing 20 together form a continuous liquid metal bearing running surface, which in this case extends linearly in the form of an outer cylindrical surface that forms part of the liquid metal bearing housing. Figure 2AThe bushing 20 and the anode disk 5 are shown still as separate components, and Figure 2B They are shown in their final state after the establishment of the material bond 21 via friction welding (and further mechanical processing). As explained, the friction welding in the axial direction leads to a truncation of the connection port 16 and the bushing 20 in the region of the connection area.

[0065] In the subsequent description of further embodiments, in which identical or substantially identical parts are affected, identical reference numerals are used and primarily the differences with respect to the first embodiment are addressed.

[0066] exist Figure 3 In the second embodiment shown, the thickness of the anode disk 5' (measured in the axial direction) increases continuously in the radially inward direction. In particular, the thickness increases from a reference thickness d R The thickness d in the region of the hole 12 increases by 30-300% starting from the mid-radius of the region of the tilted focal track surface 10 until the maximum thickness d in the region of the hole 12 II (Including all components integrally bonded to the anode disk 5', ie in the present case the connection port 16). Furthermore, even excluding the integrally formed connection port 16, the thickness is increased from the reference thickness d R The thickness d in the inner region that is critical for this purpose begins to increase by 20-150% in the radially inward direction. I Measured directly (radially) outside the connection port 16 .

[0067] exist Figure 4 In the third embodiment shown, in contrast to the first embodiment, the anode disk 5 has an extension port 24 on the side opposite the bushing 20, which extends the (passage) hole 12 of the anode disk 5 with its inner wall 26 and projects relative to the peripheral surface on the outside of the anode disk 5. The inner wall 26 of the extension port 24 is likewise circumferentially formed as a liquid metal bearing running surface and thus forms part of the liquid metal bearing housing. In addition, Figure 4 Shown is the thickness d from the reference R Start until the maximum thickness d II The thickness of the anode disk 5 (including all components integrally bonded to the anode disk 5, ie in the present case the connection port 16 and the extension port 24) is increased. Figure 5 In the fourth embodiment shown, in contrast to the first embodiment, the anode disk 5 ″ does not have a connection port. Instead, the bushing 20 is directly bonded to the flat surface of the anode disk 5 ″ via diffusion bonding.

[0068] exist Figure 6-9 In the embodiment shown, the bushing 20 is arranged on the same side as the focal track 6. Compared with the first embodiment, in Figure 6In the fifth embodiment shown, the connection port 16' is provided on the anode disk 5'', also on one side of the focal track 6. Figure 7 In the sixth embodiment shown, the anode disk 5" - similar to the fourth embodiment (see Figure 5 )—does not have a connection port. Instead, the bushing 20 is bonded directly to the flat surface of the anode disk 5" via diffusion bonding. Figure 8 The seventh embodiment shown in FIG. 1 differs from the sixth embodiment in that the thickness of the anode disk 5 ″” increases continuously in the radially inward direction.

[0069] Figure 9 A rotating X-ray anode system 27 is shown, wherein according to a fifth embodiment (see Figure 6 ) forms the rotating X-ray anode 2 as well as the anode disk 5 ″′, the connection port 16 ′ and the bushing 20. Also shown is a sleeve 28 inserted onto the inner side, on which the liquid metal bearing inner shell is formed. A bearing gap 30 is formed between the liquid metal bearing inner shell of the sleeve 28 and the liquid metal bearing outer shell, which is filled with liquid metal (not shown) during use. Two exemplary variations for forming the sleeve 28 are shown above the rotating X-ray anode. In the first variation A (in Figure 9 , once on the left in a top view and once on the right in a cross section inside the rotating X-ray anode 2), the sleeve 28 has a tubular basic shape and a smooth surface on the outside. In the second variant B ( Figure 9 As shown at the top of the third figure from the left, once in a top view and once in a cross-section to the right, the sleeve 28' has two surface-structured run sections 32, 34, which are spaced apart in the axial direction. The sleeve 28' also has a coolant duct 36 extending on the inside, which has a coolant pipe 40 inserted into a blind hole 38. The diameter of the coolant pipe 40 is selected to be correspondingly smaller than the diameter of the blind hole 38, so that, for example, coolant can flow in through the coolant pipe 40 and flow back outward through the annular duct formed between the coolant pipe 40 and the blind hole 38.

[0070] Manufacturing example:

[0071] Example 1: The following describes the manufacturing process of a rotating X-ray anode of the present invention, wherein the anode disk and the bushing are formed of MHC and are bonded to each other by friction welding. First, the anode disk and the short column having a cylindrical basic shape are manufactured by powder metallurgy, which powder metallurgy includes the steps of providing the corresponding starting powder (for MHC), pressing and sintering, and in this case includes subsequent forming (forging of the anode disk; radial forging of the short column). The short column is machined so that it has a tubular basic shape to form the subsequent bushing. In addition, during the forming (forging) process, a protruding tubular connection port (with an axial length of 40 mm) is forged into the center of the anode disk on one side, which means that the connection port is formed integrally from the material of the anode disk. The end face of the tubular short column and the end face of the connection port both have a 2000 mm diameter. 2 of the area to be welded and an inner diameter of 44 mm (from which the outer diameter is determined). In the present case, a friction welding machine with direct drive of the spindle is used. The tubular stub is clamped in the (non-rotating) holder of the friction welding machine, while the anode disk is clamped in the (rotating) spindle holder. Subsequently, the anode disk is set to rotate (2000 revolutions per minute) and pressed against the stub with a friction pressure of 30 bar. Subsequently, the drive of the anode disk is stopped and the compression pressure is increased to 65 bar. The total friction time, i.e. the time during which relative rotational movement occurs between the anode disk and the stub, is 3 seconds. Machining operations then follow to establish the final geometry, and the tubular stub is then formed into a bushing. As explained at the beginning, other mating parts, coatings, coverings, etc. can also be added. Depending on the geometry of the component and the processing steps, one or more low-stress anneals (e.g. at a temperature in the range of 1100°C-1300°C) can be included during the manufacturing process.

[0072] Example 2: The following describes the manufacturing process of a rotary X-ray anode according to the present invention, in which the anode disk and bushing are formed from TZM and joined to each other by friction welding. The same steps and parameters as in Example 1 are used, with the following exceptions: the starting powder for manufacturing the anode disk and stub is provided from TZM (rather than MHC). The friction pressure used is only 25 bar, and the compression pressure is increased to only 60 bar after the anode disk has been driven.

[0073] Example 3: The following describes the manufacturing process of a rotating X-ray anode according to the present invention, in which the anode disk and the bushing are formed from TZM and bonded to each other via diffusion bonding. First, the anode disk and the tubular stub are manufactured from TZM in the same manner as in the second working example. The end faces of the tubular stub (to be bonded) and the end faces of the connection port (to be bonded) are both mechanically processed and then ground and / or polished to provide smooth, flat surfaces. Subsequently, the two components, with their end faces abutting each other, are diffusion bonded at a temperature of 1700°C and a pressure of 10 MPa for at least 5 minutes (preferably within a range of 6-15 minutes).

[0074] The present invention is not limited to the working examples shown in the drawings. More specifically, the liquid metal bearing running surface of the liquid metal bearing outer shell does not necessarily have to have a linear progression in the form of an outer cylindrical surface; as mentioned at the outset, it can also have a stepped profile, a circumferential ridge, etc., with the liquid metal bearing inner shell typically then having a correspondingly adapted profile.

Claims

1. A rotating X-ray anode with an integrated liquid metal bearing housing, comprising Anode disk (5; 5'; made of Mo or Mo-based alloy 5'), having a hole (12) formed centrally in the region of the axis of rotation (4), said hole extending in the axial direction at least through a portion of said anode disk (5; 5'; 5'"), and A bushing (20) made of Mo or a Mo-based alloy, in, The inner wall (22) of the bushing (20) is circumferentially formed as a liquid metal bearing running surface at least in its axial section and forms a first subsection of the liquid metal bearing housing. and wherein the liquid metal bearing housing is formed by a first subsection and an adjacent second subsection and has a continuous liquid metal bearing running surface, It is characterized by: The anode disk (5; 5'; 5'") has a connection port (16; 16') on a side facing the bushing (20), the inner wall (18) of the connection port extending the hole (12) in the anode disk (5; 5'; 5'") and the connection port protruding relative to the outer peripheral surface on the outer side of the anode disk (5; 5'; 5'"), at least one axial section of the inner wall (18) of the connection port (16; 16') being circumferentially formed as a liquid metal bearing running surface and forming part of the second subsection of the liquid metal bearing housing, and a material-bonded connection (21) being formed on the anode disk (5; 5'; The material-bonded connection (21) between the protruding connection port (16; 16') of the sleeve (20) is established via a friction welding connection or a beam welding connection.

2. The rotating X-ray anode according to claim 1, characterized in that The Mo-based alloy is MHC and / or TZM, The MHC has the following composition: - 1.00-1.30 wt.% Hf content, -500-1200μg / g C content, -Residue: Mo, The content of any metal impurities present is ≤5000μg / g, and the total content of any H, N and O impurities present is ≤1000μg / g; And wherein TZM has the following composition: - 0.40-0.55 wt.% Ti content, -0.06~0.12 wt% Zr content, -50-500 μg / g C content, -Residue: Mo, The content of any metal impurities present is ≤5000 μg / g, and the total content of any H, C, N and O impurities present is ≤1500 μg / g.

3. The rotating X-ray anode according to claim 1 or 2, characterized in that: The anode disk (5; 5'; 5'") and the bushing (20) are each formed of molybdenum or are each formed of the same molybdenum-based alloy.

4. The rotating X-ray anode according to claim 1 or 2, characterized in that: The material-bonded connection (21) is a friction welding connection.

5. The rotating X-ray anode according to claim 1 or 2, characterized in that: The hole (12) in the anode disk (5) is formed as a passage hole, the anode disk (5) has an extension port (24) on the side opposite to the bushing (20), the inner wall (26) of the extension port extends the passage hole (12) of the anode disk (5), and the extension port protrudes relative to the outer peripheral surface on the outer side of the anode disk (5), at least one axial section of the inner wall (26) of the extension port (24) is circumferentially formed as a liquid metal bearing running surface and forms part of the second subsection of the liquid metal bearing housing.

6. The rotating X-ray anode according to claim 1 or 2, characterized in that: The thickness of the anode disk (5') increases in radial direction towards the rotation axis (4), wherein the increase in thickness is from the middle in the region of the inclined focal track surface (10) with a reference thickness (d R ) up to the thickness (d II ) is 30-300%.

7. The rotating X-ray anode according to claim 1 or 2, characterized in that: The anode disk (5; 5'; 5″′) has a plurality of slits which are evenly arranged on the circumference and pass through the anode disk (5; 5′; 5"'), each of the plurality of slits is formed on the anode disk (5; 5'; 5"') and the outer circumference of the anode disk (5; 5'; 5″′) in a radial section in the region between the holes (12).

8. A rotating X-ray anode system comprising a rotating X-ray anode with an integrated liquid metal bearing housing according to any one of claims 1 to 7, and a liquid metal bearing inner shell that has been inserted into the liquid metal bearing housing and has a liquid metal bearing running surface, wherein: The liquid metal bearing outer shell and the liquid metal bearing inner shell are matched with each other so that a defined bearing gap (30) is formed therebetween.

9. The rotating X-ray anode system according to claim 8, characterized in that: In the region of at least one axial end section of the liquid metal bearing running surface at the liquid metal bearing outer shell and / or the liquid metal bearing running surface at the liquid metal bearing inner shell, at least one circumferential mechanical boundary element is provided, which, in use, limits the flow of liquid metal present in the bearing gap (30) in the axial direction.

10. The rotating X-ray anode system according to claim 8 or 9, characterized in that: In the region of at least one axial end section of the liquid metal bearing running surface at the liquid metal bearing outer shell and / or the liquid metal bearing running surface at the liquid metal bearing inner shell, a circumferential coating is provided, which during use inhibits wetting of liquid metal in the bearing gap (30).

11. The rotating X-ray anode system according to claim 8 or 9, characterized in that: The liquid metal bearing inner shell is formed on a sleeve (28') which is guided through the bushing (20) at least into the hole (12) in the anode disk (5'').

12. The rotating X-ray anode system according to claim 8 or 9, characterized in that: The liquid metal bearing running surface on the liquid metal bearing outer shell and / or the liquid metal bearing running surface on the liquid metal bearing inner shell has at least two circumferential surface-structured running sections (32, 34) spaced apart in the axial direction.

13. A method for manufacturing a rotating X-ray anode according to any one of claims 1 to 7, characterized by the following steps: providing an anode disk (5; 5'; 5'') made of Mo or a Mo-based alloy, Provide short columns of Mo or Mo-based alloys, The stud is bonded to the material of the anode disk (5; 5'; 5'") so that the stud is centrally arranged with respect to the axis of rotation (4) of the anode disk (5; 5'; 5'"), and The anode disk (5; 5'; 5'") and the stub are machined to form a rotating X-ray anode (2) with an integrated liquid metal bearing housing, wherein: The stub forms a bushing (20) with a liquid metal bearing running surface, and the anode disk (5; 5'; 5'") has a hole (12) in which at least one axial section of the inner wall (14) is circumferentially formed as a liquid metal bearing running surface.

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