CN102468099B - Enhancing barrier for liquid metal bearings - Google Patents

Abstract

This application relates to enhanced barriers for liquid metal bearings. The present disclosure is directed to preventing high voltage instability within an X-ray tube. For example, in one embodiment, an X-ray tube is provided. The X-ray tube (10) generally includes a stationary member (24) and a rotating member (18) configured to rotate relative to the stationary member (24) during operation of the X-ray tube (10). The x-ray tube (10) also includes: liquid metal bearing material disposed in the space (60) between the stationary member (24) and the rotating member (26); seals (66, 72) adjacent to the space (60) liquid metal bearing material disposed to seal (66, 72) the space (60); and, surface area enhancing material (80, 82) disposed axially opposite the space (60) The seal (66, 72) is disposed on one side of the seal (66, 72) and disposed within the surface area enhancing material (80, 82) to trap liquid metal bearing material leaking from the seal (66, 72).

Description

Reinforced Barriers for Liquid Metal Bearings

technical field

The subject matter disclosed herein relates to maintenance of X-ray tube voltage, and more particularly to features for trapping liquid metal within an X-ray tube.

Background technique

Various diagnostic and other systems may utilize X-ray tubes as the radiation source. In medical imaging systems, for example, X-ray tubes are used as X-ray radiation sources in projection X-ray systems, fluoroscopy systems, tomosynthesis systems and computer tomography (CT) systems. Radiation is emitted in response to a control signal during an examination or imaging sequence. The radiation passes through the subject of interest, such as a human patient, and a portion of the radiation strikes a detector or film on which image data is collected. The negative is then processed in a conventional projection X-ray system to produce an image that can be used by a radiologist or attending physician for diagnostic purposes. In digital x-ray systems, digital detectors generate signals representative of the amount or intensity of radiation impinging on discrete pixel regions of the detector surface. In a CT system, a detector array (comprising a series of detector elements) produces similar signals through various positions as the gantry is moved around the patient.

X-ray tubes are typically operated in cycles that include periods in which high voltages are generated between certain components (e.g., when generating X-rays), and cycles in which lower voltages are used (e.g., the X-ray tube is not generating X-ray radiation) staggered. For example, in a typical configuration, a high voltage is generated between a cathode that generates an electron beam and a target anode that is hit by the electron beam, and a target anode. A high voltage is used to accelerate the electron beam towards the anode, and the bombardment of the electrons results in the generation of X-rays. Therefore, in the case of high voltage instability, the X-ray tube may not be able to generate a suitable X-ray flux for imaging. In embodiments where the x-ray tube is clinical, such as in the imaging systems described above, these instabilities can slow down or completely prevent the imaging system's ability to perform patient examinations. A solution is therefore needed to limit the instability of the high voltage in the X-ray tube.

Contents of the invention

In one embodiment, an X-ray tube is provided. The X-ray tube generally includes a fixed member and a rotating member configured to rotate relative to the fixed member during operation of the X-ray tube. The X-ray tube also includes: a liquid metal bearing material disposed in a space between the stationary member and the rotating member; a seal disposed adjacent the space to seal the liquid metal bearing material in the space; and a surface area enhancing material , disposed on a side of the seal axially opposite the space and configured within the enhanced surface area material to trap liquid metal bearing material leaking from the seal.

In another embodiment, an X-ray tube is provided. The X-ray tube generally includes a fixed member and a rotating member configured to rotate relative to the fixed member during operation of the X-ray tube. The x-ray tube also includes: a liquid metal bearing material disposed in a space between the shaft and the sleeve; a first seal disposed adjacent a first end of the space to seal the liquid metal bearing material in the space a second seal disposed adjacent the second end of the space to seal the liquid metal bearing material in the space; a first ring disposed adjacent the first seal and made of a surface area enhancing material to seal the liquid metal bearing material in the space a ring that traps liquid metal bearing material that leaks from the first seal; and, a second ring that is positioned adjacent to the second seal and is made of an enhanced surface area material to trap liquid metal bearing material that leaks from the second seal in the second ring. Liquid metal bearing material.

In yet another embodiment, a method of manufacturing an X-ray tube is provided. The method includes: disposing a sleeve around a shaft; disposing a liquid metal bearing material in a space between the sleeve and the shaft; disposing a seal adjacent at least one end of the space to seal the liquid metal bearing material in the space; And, an enhanced surface area material is disposed adjacent the seal to trap liquid metal bearing material that leaks from the seal within the enhanced surface area material.

In one embodiment, a method of manufacturing an X-ray tube is provided. Included in an x-ray tube: a rotating member; a sleeve disposed about a fixed shaft; a liquid metal bearing material disposed in a space between the rotating member and the shaft; a seal adjacent at least one end of the space Disposed to seal liquid metal bearing material in the space, the method includes disposing an enhanced surface area material adjacent the seal to trap liquid metal bearing material leaking from the seal within the enhanced surface area material.

Description of drawings

These and other features, aspects and advantages of the present invention will become better understood when the following detailed description of the invention is read with reference to the accompanying drawings, wherein like reference numerals refer to like parts throughout, wherein:

FIG. 1 is a diagrammatic illustration of an embodiment of an X-ray tube according to the present disclosure, in which materials that enhance surface area may be used to prevent high voltage instabilities;

2 is a cross-sectional view of the anode assembly of the X-ray tube of FIG. 1 in which surface area enhancing material is provided to prevent leakage of liquid metal bearing material according to the present disclosure;

3 is a cross-sectional view of one end of the anode assembly of the X-ray tube of FIG. 1 with enhanced surface area material positioned adjacent to a bearing seal to prevent leakage of liquid metal bearing material according to the present disclosure;

4 is a cross-sectional view of one end of the anode assembly of the X-ray tube of FIG. 1 with enhanced surface area material disposed adjacent a thrust seal to prevent leakage of liquid metal bearing material, according to the present disclosure;

5 is a cross-sectional view of one end of the anode assembly of the X-ray tube of FIG. 1 having an enhanced surface area material integrated with a thrust seal to prevent leakage of liquid metal bearing material according to the present disclosure; and

6 is a process flow diagram illustrating an embodiment of a method of fabricating an X-ray tube having one or more enhanced surface area materials for preventing high voltage instabilities in accordance with the present disclosure.

List of component symbols:

10 X-ray tubes

12 Anode assembly

14 Cathode assembly

16 envelopes

18 rotors

20 anodes

22 bearings

24 Shaft

26 Bearing sleeve

28 Coolant flow path

30 focal plane

32 electron beam

34 Cathode

36 electrical leads

38 Central insulating housing

40 masks

42 cathode cup

46 X-ray radiation

48 X-ray apertures

60 area

62 first end

64 second end

66 Seals

70 Circumferential notch

72 Seals

74 spacer

78 Circumferential notch

80 First ESA Circle

82 Second ESA Circle

86 inside

88 shoulder

100 ways

102 Arranging a rotating member around a fixed shaft to form a bearing with liquid metal lubricant

104 Provide seals on at least one side of the bearing to seal liquid metal lubricant in the bearing

106 Placement of enhanced surface area material adjacent a seal to trap liquid metal lubricant that escapes from the seal during use

detailed description

As mentioned above, X-ray tubes often generate high voltages between the cathode and anode. A high voltage can be used to accelerate electrons from the cathode to the anode. Certain X-ray tubes have a rotating anode disk which allows different parts of the disk to be hit by the electron beam to spread the thermal energy thus generated. The anode disc may be rotatably supported by bearings, such as liquid metal lubricated ball bearings or helical groove bearings. Disadvantageously, a portion of the liquid metal lubricant material may leak from the bearing and associated seals in situations where the bearing is placed under load, such as when an X-ray tube is rotated about an associated subject on a gantry. The escaping liquid metal material can be in liquid, atomized and/or vapor form and can create high voltage instability within the tube. Accordingly, it is now recognized that an improved solution is needed to trap liquid metal lubricant material escaping from the bearing so that the high voltage within the tube can be maintained. Typical methods for capturing leaked liquid metal are often unreliable and insufficient to capture the proper amount of liquid metal lubricant material to prevent high voltage instability. For example, typical solutions often do not trap any significant amount of atomized and/or vaporized liquid metal lubricant, and may not provide sufficient barrier properties to substantially completely contain the liquid metal lubricant.

Embodiments disclosed herein thus address these and other shortcomings of prior solutions by providing enhanced surface area materials capable of trapping liquid, atomized and vaporized liquid metal bearing materials. The surface area enhancing material may be disposed adjacent to the seal(s) of the X-ray tube or may be formed as part of the seal(s) of the X-ray tube, or both. Materials that enhance surface area may include meshes, felts, porous loops, pile, woven materials, pressed/sintered materials, and the like. In certain embodiments, the surface area enhancing material acts as a physical barrier to prevent leakage of the liquid metal bearing material. In additional embodiments, the surface area enhancing material may also chemically interact (eg, may be a wettable material) with the liquid metal bearing material to prevent leakage of the liquid metal bearing material.

In this disclosure, non-limiting examples in which surface area enhancing materials may be used are described with respect to FIG. 1 . Variations of surface area enhancing material placement are described with respect to FIGS. 2 to 5 . With the foregoing description in mind, Figure 1 illustrates an embodiment of an X-ray tube 10 according to the present approach, which may include features configured to provide enhanced entrapment of liquid metal bearing material. In the illustrated embodiment, X-ray tube 10 includes an anode assembly 12 and a cathode assembly 14 . X-ray tube 10 is supported by an anode assembly and a cathode assembly within an envelope 16 that defines a region of relatively lower pressure (eg, vacuum) than the surrounding environment where high voltages may exist. The envelope 16 may be within a casing (not shown) filled with a cooling medium, such as oil, which surrounds the envelope 16 . The cooling medium also provides high voltage insulation.

Anode assembly 12 generally includes a rotor 18 and a stator (not shown) external to X-ray tube 10 that at least partially surrounds rotor 18 for causing rotation of anode 20 during operation. Anode 20 is rotatably supported by bearing 22 which, when rotated, also causes anode 20 to rotate. The anode 20 has an annular shape, such as a disc, and an annular opening in its center for receiving the bearing 22 . In general, the bearing 22 includes a fixed portion (such as the shaft 24 ) and a rotating portion (such as the bearing sleeve 26 to which the anode 20 is attached). While the shaft 24 is presently described in the context of a fixed shaft, it should be noted that this approach is also applicable to embodiments in which the shaft 24 is a rotating shaft. In this configuration, it should be noted that the x-ray target may also rotate as the shaft rotates. Considering the foregoing description, in one embodiment, the bearing 22 can be a spiral groove bearing disposed between the bearing sleeve 26 and the shaft 24 , and the spiral groove bearing has a liquid metal lubricant. Indeed, certain embodiments of the bearing 22 may conform to those described in U.S. Patent Application Serial No. 12/410518, filed March 25, 2009, entitled "INTERFACE FOR LIQUID METAL BEARING AND METHODOF MAKING SAME," which The entire disclosure of the application is hereby incorporated by reference in its entirety. The shaft 24 optionally includes a coolant flow path 28 through which a coolant, such as oil, may flow to cool the bearing 22 . In the illustrated embodiment, the coolant flow path 28 extends along the longitudinal length of the x-ray tube 10, which is depicted as a straddle configuration. However, it should be noted that in other embodiments the coolant flow path 28 may extend through only a portion of the X-ray tube 10, such as in configurations in which the X-ray tube 10 is cantilevered when placed in the imaging system.

During operation, rotation of bearing 22 advantageously allows the front portion of anode 20 (on which target or focal plane 30 is formed) to be struck by electron beam 32 periodically rather than continuously. Such periodic bombardment may allow for dispersion rather than concentration of the resulting thermal energy, which may lead to one or more anode failure modes (eg, cracking, deformation, rupture). In general, anode 20 may rotate at high speed (eg, 100 to 200 Hz). Anode 20 may be fabricated to include various metals or compounds, such as tungsten, molybdenum, copper, or any material that contributes to bremsstrahlung (ie, slows down radiation) when bombarded by electrons. Anode surface materials are generally selected to have a relatively high refractory value in order to withstand the heat emitted by electrons striking the anode 20 . Additionally the space between cathode assembly 14 and anode 20 may be evacuated in order to minimize collisions of electrons with other atoms and maximize potential. In some X-ray tubes, a voltage in excess of 20 kV develops between cathode assembly 14 and anode 20 such that electrons emitted by cathode assembly 14 become attracted to anode 20 . This voltage can be adversely affected by the presence of stray atoms and/or particles, such as atoms and/or particles of liquid metal bearing material.

Electron beam 32 is produced by cathode assembly 14 and, more specifically, cathode 34 that receives one or more electrical signals via a series of electrical leads 36 . The electrical signal may be a timing/control signal that causes cathode 34 to emit electron beam 32 at one or more energies and at one or more frequencies. Additionally, the electrical signal may at least partially control the electrical potential between cathode 34 and anode 20 . Cathode 34 includes a central insulating housing 38 from which shroud 40 extends. A shroud 40 encloses the lead wire 36 which extends to a cathode cup 42 mounted at the end of the shroud 40 . In certain embodiments, cathode cup 42 acts as an electrostatic lens that focuses electrons emanating from a thermionic filament within cup 42 to form electron beam 32 .

As a result of the control signal delivered to cathode 34 via lead 36 , the thermionic filament within cup 42 is heated and electron beam 32 is generated. The beam 32 impinges on the focal plane 30 of the anode 20 and generates X-ray radiation 46 which is diverted from an X-ray aperture 48 of the X-ray tube 10 . The direction and orientation of the x-ray radiation 46 can be controlled by a magnetic field generated externally to the x-ray tube 10 or by electrostatic means at the cathode 34 and the like. The resulting field may generally shape the X-ray radiation 46 into a focused beam (such as a cone beam as shown). X-ray radiation 46 exits the tube 10 and is directed generally towards the subject of interest during the examination procedure.

As noted above, the X-ray tube 10 may be used in systems in which the X-ray tube 10 is displaced relative to a patient, such as a CT imaging system in which the X-ray radiation source is rotated about an associated subject on a gantry. As the x-ray tube 10 rotates along the gantry, various forces, such as centrifugal forces, are placed on the bearings 22 . In some cases, the load on the bearing 22 can cause the bearing 22 to lose a portion of the liquid metal bearing material. For example, bearing 22 may expand slightly and a portion of the liquid metal bearing material may leak out. To mitigate the effects of such leaks, the present embodiments provide one or more features to trap leaked liquid metal bearing material.

FIG. 2 provides a cross-sectional view of an embodiment of a portion of anode assembly 12 that may include liquid metal bearing material retention features. As noted above, the anode assembly 12 includes bearings 22 that allow the anode 20 ( FIG. 1 ) to rotate. In the illustrated embodiment, the bearing 22 is a helical groove bearing formed between the bearing sleeve 26 and the shaft 24 . The bearing 22 is lubricated using a liquid metal lubricating material, which may include Ga and/or alloys thereof. The liquid metal bearing material typically resides in the region 60 between the bearing sleeve 26 and the shaft 24 and may leak out of the bearing 22 at the first end 62 of the bearing 22 and/or the second end 64 of the bearing 22 during operation. . First end 62 faces generally in the direction of anode 20 ( FIG. 1 ), while second end 64 faces generally in the direction of rotor 18 ( FIG. 1 ). Disposed at the first end 62 is a first set of seals 66 which may include one or more rotatable members. As shown, the first set of seals 66 is part of a one-piece rotatable member having protrusions that form a seal when placed on the shaft 24 . The first set of seals 66 may be considered a small gap configured to trap liquid metal bearing material that escapes from the bearing 22 by surface tension. For example, the first set of seals 66 may include a very small gap with an anti-wetting surface that causes the liquid metal bearing material to be repelled by surface tension between the anti-wetting surface and the liquid metal bearing material. The first set of seals 66 is secured to the bearing sleeve 26 (eg, via a seal bolt) such that the first set of seals 66 rotates as the bearing 22 rotates. In addition to the first set of seals 66, there may be one or more circumferential notches 70 configured to trap liquid metal bearing material that may leak through small gaps. For example, the liquid metal bearing material may experience centrifugal force during rotation of bearing 22 , which may force it to be directed past first set of seals 66 and into one or more of circumferential notches 70 . Additionally, in certain embodiments, the circumferential recess 70 may be coated and/or include one or more materials that are wettable by the liquid metal bearing material to provide a metallurgical interaction to increase retention. In this regard, the circumferential notches can be considered liquid metal bearing material traps.

In addition to the first set of seals 66 , the bearing sleeve 26 is attached to a second set of seals 72 disposed at the second end 64 of the bearing 22 . Specifically, the second set of seals 72 is attached to the bearing sleeve 26 via a spacer 74 that separates the second set of seals 72 from the bearing sleeve 26 . For example, mounting bolts may secure bearing sleeve 26 to spacer 74 and spacer 74 to second set of seals 72 . However, it should be noted that other configurations are contemplated in the present invention, such as configurations in which the bearing sleeve 26 is secured directly to the second set of seals 72 and the like. Second set of seals 72 (similar to first set of seals 66 ) is generally configured to trap liquid metal bearing material leaking from bearing 22 via capillary forces. Like the first end 62, the second end also includes one or more circumferential notches 78, which may have surfaces that are wettable by the liquid metal bearing material.

Although the anode assembly 12 includes a first set of seals 66 and a second set of seals 72 disposed at opposite ends of the bearing 22, it should be noted that the liquid metal bearing material may still escape and cause high voltages within the x-ray tube 12 to be unbalanced. stability. For example, the first set of seals 66 and the second set of seals 72 typically rely on the surface tension of the liquid metal bearing material to prevent low pressure leakage due to small gaps and wetting-resistant surfaces. However, in the presence of pressure peaks, first circumferential notch 70 and second circumferential notch 78 may not be sufficient to capture liquid metal bearing material leaking from bearing 22 through first set of seals 66 and second set of seals 72 The total amount may either be insufficient to capture atomized and/or vaporized liquid metal bearing material, or both. Thus, in addition to or instead of the circumferential notches 70, 78, the present solution also provides one or more annular members having an enhanced surface area material configured to trap escaped liquid metal bearing material. The entrapment may involve mechanical entrapment, such as due to the porous nature of the material, or metal interactions, such as due to the wettability of the material utilizing the enhanced surface area of the liquid metal bearing material, or both.

Specifically, the anode assembly 12 includes a first enhanced surface area (ESA) ring 80 disposed toward the first end 62 forward of the first set of seals 66 (i.e., at the bearing 60 axially opposite end). A second ESA ring 82 is disposed toward the second end 64 just behind the second set of seals 72 on the axially opposite end of the bearing 60 . In general, the first ESA ring 80 and the second ESA ring 82 can be configured to trap any leakage past the first set of seals 66 and the second set of seals 72 and in some embodiments the circumferential notches 70, 78, respectively. Liquid metal bearing material. The first ESA ring 80 and the second ESA ring 82 can be about the same size as the first set of seals 66 and the second set of seals 72 , smaller than the first set of seals 66 and the second set of seals 72 , or larger than the first set of seals 66 and the second set of seals 72 . A set of seals 66 and a second set of seals 72 . It should be noted, however, that the first ESA ring 80 and the second ESA ring 82 may be at least the same size as their adjacently disposed circumferential notches. As shown, the first ESA ring 80 is about the same size as the circumferential notch 70 and the second ESA ring 82 is larger than the circumferential notch 78 . It should be noted, however, that other sizes and configurations are also contemplated, as will be discussed with respect to FIGS. 2-5 . The first ESA ring 80 and the second ESA ring 82 may be full rings or partial rings, and generally include annular openings for receiving the shaft 24 . The first ESA ring 80 and the second ESA ring 82 may be attached directly to the shaft 24 or may be attached to other components of the anode assembly 12 . In certain embodiments, the first ESA ring 80 and the second ESA ring 82 may be press-fit or fitted so as to substantially restrict axial movement (eg, toward and away from the first end 62 and the second end 64 ). Additionally, first ESA ring 80 and second ESA ring 82 may be constructed of a material that is stable under the operating conditions of X-ray tube 10 .

First ESA ring 80 and second ESA ring 82 may be formed from a variety of materials and a variety of processes. For example, the first ESA ring 80 and the second ESA ring 82 may comprise materials wettable by the liquid metal bearing material, such as gold (Au), silver (Ag), copper (Cu), nickel (Ni), and similar materials . Alternatively or additionally, first ESA ring 80 and second ESA ring 82 may comprise a material that is substantially non-wettable by the liquid metal bearing material, such as graphite or the like. It should be noted that these materials, being substantially non-wettable, operate by providing a physical barrier. Furthermore, wettable or non-wettable ESA materials according to the present approach are designed such that they are mechanically compliant and conform to the joint. Alternatively, a non-compliant arrangement according to the present solution has no contact between the fixed member and the rotating member. First ESA ring 80 and second ESA ring 82 may be formed by a variety of processes, as described above. In general, the surface area enhancing material formed by first ESA loop 80 and second ESA loop 82 may include mesh, pile, felt, woven material, foam, pressed/sintered material, and the like. In certain embodiments, the enhanced surface area material can be produced by powder metallurgy to produce a material with small pores (eg, micropores). In general, the first ESA ring 80 and the second ESA ring 82 may be configured such that any escaped liquid metal bearing material becomes trapped within the pores or fiber network of the surface area enhancing material. In embodiments where the enhanced surface area material includes wettable by liquid metal bearing material, first ESA ring 80 and second ESA ring 82 may be considered mechanical and metallurgical sinks for leaked liquid metal bearing material.

FIG. 3 shows an embodiment of the first ESA ring 80 in which it is larger in size than the circumferential notch 70 . It should be noted, however, that while the first ESA ring 80 does not completely cover the first set of seals 66, such embodiments are contemplated in the present invention. During operation of the illustrated embodiment and in the event that the liquid metal bearing material leaks from the bearing 60, a portion of the liquid metal bearing material may flow from the second end 64 (e.g., from an area near the center of the shaft 24) toward the first end 62. move. In this case, the liquid metal bearing material may first encounter the circumferential recess 70 of the first set of seals 66 . However, at least a portion of the leaked liquid metal bearing material may be completely retained by the first set of seals 66 as described above. Additionally, some liquid metal bearing materials may be in atomized and/or vaporized form. Advantageously, the first ESA ring 80 may contain pores of sufficient size to trap liquid metal bearing material even when in atomized/vaporized form. As noted above, the first ESA ring 80 may be metal wool, metal foam, sintered metal, braided metal, porous graphite, or the like. Additionally, the first ESA ring 80 may be a partial ring that can be placed on the shaft 24 from the side, or may be a complete annular ring having an annular opening to receive the shaft 24 through its center, among others. Condition.

While the first ESA ring 80 is shown as being separate from the first set of seals 66 , it should be noted that in other embodiments the first ESA ring 80 may be formed as part of the first set of seals 66 . For example, the first set of seals 66 may include a combination of an annular notch 70 and a surface area enhancing material. Alternatively, the first set of seals 66 may have the first ESA ring 80 disposed in one of the circumferential notches 70 , for example at the circumferential notch disposed toward the first end 62 . In other embodiments, the first ESA ring 80 may be secured to the first set of seals 66 . For example, the first ESA ring 80 may be press fit into the first set of seals 66 , may be interlocked with the first set of seals 66 , or may be bolted to the first set of seals 66 .

Turning now to FIG. 4 , an embodiment of the second ESA ring 82 is shown in which it is about the same size as the circumferential notch 78 . As depicted, the second ESA ring 82 may be sized to extend entirely along the inner face 86 of the rotor 18 . Thus, it can be understood from the description of FIG. 4 that the second ESA ring 82 prevents liquid metal bearing material from entering a portion of the rotor 18 .

For example, bearing sleeve 26 may rotate about shaft 24 during operation of X-ray tube 10 . In embodiments where a load is placed on the bearing 60 , a portion of the liquid metal bearing material may leak from the bearing area, for example in a direction from the first end 62 towards the second end 64 . The escaped liquid metal bearing material may then travel past the spacer 74 , which may also be a seal against the shoulder 88 of the bearing sleeve 26 . It is presently contemplated that spacer 74 may also beneficially include one or more surface area enhancing materials. As the liquid metal bearing material advances through the anode assembly 12 , it then encounters the second set of seals 72 . The second set of seals 72 is secured to the spacer 74 as described above. Thus, the liquid metal bearing material that passes through the interface between the spacer 74 and the shoulder 88 moves through the interface between the spacer 74 and the second set of seals 72 and continues to the circumferential notch 78 .

Liquid metal bearing material (eg, atomized and/or vaporized bearing material) that is not trapped within the circumferential notch 78 then encounters the second ESA ring 82 . According to the present embodiment, the second ESA ring 82 (similar to the first ESA ring 80) may be made of a material that is wettable or substantially non-wettable by the liquid metal bearing material. As an example, the second ESA ring 82 may include Au, Cu, Ni, graphite, or the like. Second ESA ring 82 may be formed using a variety of methods known in the art, including powder metallurgy, pressing, sintering, braiding, stretching, and the like. In certain embodiments, the second ESA ring 82 is a mechanical trap in which it comprises a mesh or foam structure that can absorb liquid metal bearing material. Additionally, in embodiments where the second ESA ring 82 is wettable, it can be considered a mechanical and metallurgical reservoir for leaked liquid metal bearing material.

In a similar manner to the first ESA ring 80, the second ESA ring 82 may be separate from or connected to its proximately disposed seal. In the embodiment shown in FIG. 5 , the second ESA ring 82 is depicted as being integral with the second set of seals 72 . As an example, the second ESA ring 82 may be press-fit, interlocked, or otherwise secured to the second set of seals 72 . In certain embodiments, which can be understood with respect to FIG. 5 , the second ESA ring 82 can completely replace one or more of the circumferential notches. Additionally, as the liquid metal bearing material encounters the second set of seals 72 , it may also encounter the second ESA ring 82 . Indeed, the use of multiple surface area enhancing materials, such as multiple loops, is contemplated in the present invention.

In certain embodiments, a portion of the second set of seals 72 may be chemically treated in order to create the second set of seals 72 with an integral enhanced surface area material. This chemical treatment of a portion of the second set of seals 72 may create an annular or semi-annular configuration having an enhanced surface area compared to the volume of the second set of seals 72 . In other embodiments, the second ESA ring 82 may be made based on one or more tolerances of the circumferential notch 7 . Fabricating the second ESA ring 82 in this manner allows retrofitting of existing anode assemblies 12 with surface area enhancing materials in accordance with the present approach. Indeed, the present approach contemplates fabricating the first ESA ring 80 and/or the second ESA ring 82 to allow retrofitting into existing X-ray tubes.

FIG. 6 is an illustration of a process flow diagram of such a method 100 for manufacturing an X-ray tube according to the present embodiment. The method 100 begins by forming the bearing 60 ( FIG. 2 ) that rotatably supports the anode 20 ( FIG. 1 ). A rotating member such as bearing sleeve 26 of FIGS. 1-5 is disposed about a shaft such as shaft 24 of FIGS. 1-5 (block 102 ). The bearing sleeve 26 together with the shaft 24 forms a bearing 60 which in this embodiment is lubricated with a material which is metallic and liquid at room temperature (ie a liquid metal bearing material). Seals, such as either or both of the first seal 66 and the second seal 72 (FIG. 2), are provided on the sides of the bearing 60 to prevent leakage of the liquid metal bearing material from the bearing 60 (block 104 ). A surface area enhancing material (e.g., either or both of the first ESA ring 80 and the second ESA ring 80) is disposed adjacent (e.g., directly against) the seal on the axially opposite side of the bearing 60 ( Box 106). In this way, an enhanced surface area material is provided to trap any liquid metal bearing material that escapes from the seal. The enhanced surface area material can be attached directly to the shaft or to the seal. For example, the surface area enhancing material may be an annular or semi-annular structure having an annular opening in its center. The opening allows the surface area enhancing material to be disposed about the shaft to form a seal to prevent further leakage of the liquid metal bearing material. In embodiments where the surface area enhancing material is attached to the seal, it may include one or more features configured to interlock with the seal, or may be fabricated such that its extension approximates one or more features of the seal. tolerance (for example, the tolerance of the circumferential notches 70, 78).

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope is defined by the claims, and may include these modifications and other examples that occur to those skilled in the art. Other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims (9)

1. an X-ray tube, including:

Fixing component；

Rotating member, it is configured to during the operation of described X-ray tube rotate relative to described fixing component；

Liquid metal bearings material, it is arranged in the space between described fixing component and described rotating member；

First sealing member, it is arranged so that the described liquid metal bearings material being sealed in described space adjacent to described space； And

Including the first component of the material of the first enhancing surface area, it is arranged at described space axially opposing described first The front of sealing member, and be configured to retain, in the described first material strengthening surface area, the liquid spilt from described sealing member Metallic bearing material, the first described component is independent of the first described sealing member；

Wherein, the described first material strengthening surface area includes being selected for the enhancing of described liquid metal bearings material The material of wettability.

X-ray tube the most according to claim 1, it is characterised in that include the second sealing member and include the second enhancing surface area The second component of material, described second sealing member is arranged at the end in described space, and described second component is arranged at described The rear of described second sealing member that space is relative is to retain from described second close strengthen the material of surface area described second in The liquid metal bearings material that sealing spills.

X-ray tube the most according to claim 1, it is characterised in that the described first material strengthening surface area includes annular Circle.

X-ray tube the most according to claim 1, it is characterised in that the described first material strengthening surface area includes porous Material.

X-ray tube the most according to claim 4, it is characterised in that the described first material strengthening surface area includes metal Cotton, sintering metal or metal foam.

X-ray tube the most according to claim 4, it is characterised in that described first strengthen surface area material include based on The material of graphite.

X-ray tube the most according to claim 1, it is characterised in that the described first material strengthening surface area is fixed to institute State on rotating member.

X-ray tube the most according to claim 1, it is characterised in that the described first material strengthening surface area is fixed to institute State on fixing component.

X-ray tube the most according to claim 1, it is characterised in that described first strengthens described in the material of surface area Fixing component and described rotating member.