Thrust bearing vent for liquid metal bearing assembly

Abstract

The invention relates to a thrust bearing vent for a liquid metal bearing assembly. Various systems for liquid metal bearing assemblies are provided. In one embodiment, a liquid metal bearing assembly includes a first liquid metal bath, a second liquid metal bath, and a thrust bearing vent extending between the first liquid metal bath and the second liquid metal bath to discharge gas between the first liquid metal bath to the second liquid metal bath. A first end of the thrust bearing vent is connected to the first liquid metal bath at a point of the first liquid metal bath closest to a central axis of the liquid metal bearing assembly.

Description

Technical Field

[0001] Embodiments of the subject matter disclosed herein are directed to systems having a liquid metal bearing assembly and a thrust bearing vent for the liquid metal bearing assembly. Background Art

[0002] Liquid metal bearings have a longer life and are more efficient at managing thermal loads relative to roller bearings and are therefore used in a variety of operating environments. For example, certain x-ray sources or x-ray tubes utilize liquid metal bearing assemblies, which may include at least one liquid metal bearing, at least in part due to the durability and thermodynamic properties of liquid metal bearing assemblies. However, asymmetric liquid metal distribution and gas formation may occur in the liquid metal interface of the bearing. Summary of the invention

[0003] In one embodiment, the liquid metal bearing assembly includes a first liquid metal pool, a second liquid metal pool, and a thrust bearing exhaust port extending between the first liquid metal pool and the second liquid metal pool to discharge gas between the first liquid metal to the second liquid metal pool. The first end of the thrust bearing exhaust port is connected to the first liquid at a point of the liquid metal pool closest to the central axis of the liquid metal bearing assembly.

[0004] It should be understood that the above brief description is provided to introduce in a simplified form selected concepts that are further described in the detailed description. It is not meant to identify key features or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present invention will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0006] Figure 1 shows a schematic block diagram of an exemplary x-ray imaging system according to one embodiment;

[0007] Figure 2 shows a pictorial view of a portion of an x-ray source according to one embodiment;

[0008] Figure 3 A first exemplary liquid metal bearing assembly according to one embodiment is shown;

[0009] Figure 4 A first embodiment of a thrust bearing exhaust port of a liquid metal bearing assembly according to one embodiment is shown;

[0010] Figure 5 A second embodiment of a thrust bearing vent of a liquid metal bearing assembly according to one embodiment is shown;

[0011] Figure 6 A third embodiment of a thrust bearing exhaust port of a liquid metal bearing assembly according to one embodiment is shown;

[0012] Figure 7 A fourth embodiment of a thrust bearing vent of a liquid metal bearing assembly according to one embodiment is shown;

[0013] Figure 8 A fifth embodiment of a thrust bearing vent of a liquid metal bearing assembly according to one embodiment is shown; and

[0014] FIG. 9A to FIG. 9G Exemplary radial locations of thrust bearing exhaust ports relative to applied frame loads and shaft center are shown. DETAILED DESCRIPTION

[0015] The following description relates to various embodiments for a liquid metal bearing assembly, and more particularly to a thrust bearing exhaust port of a liquid metal bearing assembly. The liquid metal bearing assembly may be included in an x-ray source of an x-ray imaging system, an exemplary block diagram of which is provided in Figure 1 An embodiment of the x-ray source is shown in Figure 2 , wherein an x-ray source is provided with a liquid metal bearing assembly to enable the anode of the x-ray source to rotate. For purposes of explanation, the liquid metal bearing assembly is described herein for an x-ray source of an x-ray imaging system, and the liquid metal bearing assembly may be implemented in other systems, such as a computed tomography (CT) imaging system, without departing from the scope of the present disclosure. Figure 3 Shows Figure 2 An embodiment of a liquid metal bearing assembly, wherein the liquid metal bearing assembly is equipped with a rotating sleeve and a fixed shaft. Figures 4 to 8 Shows the settings in Figure 3 Various exemplary embodiments of a thrust bearing exhaust port between a shaft and a sleeve of a liquid metal bearing assembly. FIG. 9A to FIG. 9G Illustrative radial locations of one or more thrust bearing exhaust ports that may be positioned about a shaft relative to an applied frame load and the shaft center are shown.

[0016] Conventional methods for assembling a liquid metal bearing assembly configured as a straddle bearing include exposing a seal of the liquid metal bearing assembly and introducing liquid metal, for example, by spilling liquid metal onto the seal. In addition, the liquid metal bearing assembly can be assembled in an orientation in which the axis of rotation of the liquid metal bearing assembly is parallel to the direction of gravity. When implemented in an x-ray source or an x-ray tube, the liquid metal bearing assembly can be placed horizontally so that the axis of rotation is perpendicular to the direction of gravity. Additionally or alternatively, when implemented in an x-ray source or an x-ray tube, the liquid metal bearing assembly can be placed so that the axis of rotation is placed at a non-parallel angle relative to the direction of gravity. For example, the x-ray source or x-ray tube can be integrated into a mobile structure such as a rotating gantry of a CT imaging system. The above-mentioned assembly method and / or operation of the liquid metal bearing may cause gas to be trapped between the shaft and the sleeve of the liquid metal bearing. Due to the increase in pressure in the x-ray tube and the lack of lubrication of the bearings, the bearing performance of the journal and thrust bearings is reduced, and the trapped gas may cause instability. A liquid metal bearing assembly is desired that enables entrapped gas to escape from the region between the shaft and sleeve, thereby improving the performance and reliability of an X-ray tube.

[0017] An exemplary liquid metal bearing assembly is described herein, which includes a thrust bearing exhaust port that removes trapped gas from a pool of liquid metal positioned between a shaft and a sleeve. The thrust bearing exhaust port is positioned between the shaft and the sleeve, with the first end being located at the lowest point of the container and the second end being located in a second pool of liquid exposed to the vacuum pressure of the insert. Capillary action draws the liquid metal and any gas trapped in the first pool into the second pool through the thrust bearing exhaust port. In addition, centrifugal force moves the gallium outward and the gas inward, causing more gas to be discharged through the flange hole. In some examples, the diameter of the first end of the exhaust port is the same as the diameter of the second end of the exhaust port. Alternatively, the diameter of the first end is different from the diameter of the second end. In examples where the diameter of the first end is different from the diameter of the second end, capillary action pulls the liquid metal and any gas toward the direction of the larger diameter opening of the thrust bearing exhaust port.

[0018] One or more thrust bearing exhaust ports may be positioned radially about the shaft relative to the applied frame load and the shaft center. The location of the exhaust ports may be symmetrical or asymmetrical. The radial location of the thrust bearing exhaust ports may also affect the amount of gas exhausted due to pressure gradients within the liquid metal bearing. For example, an exhaust port positioned at the bottom allows the maximum amount of gas to be removed.

[0019] Before further discussing the liquid metal bearing assembly with thrust bearing exhaust ports, an exemplary imaging system is shown in which the liquid metal bearing assembly may be implemented. Figure 1 An x-ray imaging system 100 designed to generate x-rays is shown. The x-ray imaging system 100 may be configured to Figure 1 The x-ray imaging system 100 may be used in a computer tomography (CT) imaging system, a radiographic imaging system, a fluoroscopic imaging system, a mammographic imaging system, an interventional imaging system, a tomographic system, or the like. However, the x-ray imaging system 100 can be applied to fields other than imaging, medical devices, and the like. For example, the x-ray imaging system 100 may be deployed in devices such as crystallographic systems, security scanners, industrial scanners, x-ray photography systems, and the like. In the imaging system example, the system may be configured to image a subject 102 (such as a patient, an inanimate object, one or more manufactured parts) and / or a foreign object (such as an implant, a stent, and / or a contrast agent present in the body).

[0020] The x-ray imaging system 100 may include at least one x-ray source 104, such as an x-ray tube, configured to generate and project an x-ray radiation beam 106. Specifically, in the illustrated embodiment, the x-ray source 104 is configured to project the x-ray radiation beam 106 toward a detector array 108 and through a subject 102. In some system configurations, the x-ray source 104 may project a conical x-ray radiation beam that is collimated to lie within an XYZ plane of a Cartesian coordinate system. However, other beam profiles and / or systems that omit the detector array have been envisioned. Each detector element of the array generates a separate electrical signal that is a measurement of the x-ray beam attenuation at the detector location.

[0021] although Figure 1 Only a single x-ray source 104 and detector array 108 are depicted, but in some embodiments, multiple x-ray sources and / or detectors may be employed to project multiple x-ray radiation beams and detect the x-ray radiation beams. For example, in a CT machine use case example, multiple detectors may be used in series with an x-ray source to acquire projection data corresponding to different energy levels of a subject.

[0022] The x-ray imaging system 100 may also include an x-ray controller 110 configured to provide power and timing signals to the x-ray source 104. It should be understood that the system may also include a data acquisition system configured to sample analog data received from the detector elements and convert the analog data into digital signals for subsequent processing.

[0023] In certain embodiments, the x-ray imaging system 100 may further include a computing device 112 having a processor 114 and controlling system operation based on operator input. The computing device 112 receives operator input, including, for example, commands and / or scan parameters, via an operator console 116 operatively coupled to the computing device 112. The operator console 116 may include a keyboard, a touch screen, and / or other suitable input devices that allow an operator to specify commands and / or scan parameters.

[0024] Although Figure 1 Only one operator console 116 is shown, but more than one operator console may be included in the x-ray imaging system 100, for example, for inputting system parameters or outputting system parameters, requesting examinations, plotting data, and / or viewing images. In addition, in some embodiments, the x-ray imaging system 100 can be coupled to multiple displays, printers, workstations, and / or the like located, for example, locally or remotely and connected via a wired network and / or a wireless network. In one embodiment, the display 120 can be in electronic communication with the computing device 112 and is configured to display a graphical interface indicating information such as system parameters, control settings, imaging data, etc.

[0025] In one example, computing device 112 stores data in storage device 118. For example, storage device 118 may include a hard drive, a floppy disk drive, a compact disk read / write (CD-R / W) drive, a digital versatile disk (DVD) drive, a flash drive, and / or a solid-state storage drive.

[0026] In addition, the computing device 112 provides commands to the x-ray controller 110 and other system components for controlling system operation, such as x-ray beam formation, data acquisition and / or processing, etc. Therefore, in some embodiments, the computing device 112 controls system operation based on operator input. In detail, the computing device 112 can use operator-provided commands and parameters and / or system-defined commands and parameters to operate the x-ray controller 110, which in turn can control the x-ray source 104. In this way, the intensity and time when the x-ray beam is generated can be controlled. It should also be understood that the rotation speed of the sleeve in the x-ray source can be adjusted by the computing device 112 in conjunction with the x-ray controller 110. As described in more detail herein, the sleeve can be a rotating element of a liquid metal bearing assembly.

[0027] Various methods and processes may be stored as executable instructions in non-transitory memory on a computing device (or controller) in the x-ray imaging system 100. In one embodiment, the x-ray controller 110 may include the executable instructions in the non-transitory memory and may apply the methods to control the x-ray source 104. In another embodiment, the computing device 112 may include the instructions in the non-transitory memory and may at least partially relay the commands to the x-ray controller 110, which in turn adjusts the x-ray source output.

[0028] Figure 2 A detailed embodiment of a portion of an x-ray source, such as x-ray tube 200, is shown. Figure 2 The x-ray tube 200 shown is used as Figure 1 An example of an x-ray source 104 is shown. Thus, Figure 2 The x-ray source shown and other x-ray source embodiments described herein may include a source from Figure 1 Functional features and / or structural features of the x-ray source 104 are shown, and vice versa. In addition, alternative embodiments are also contemplated that combine features from one or more of the systems. Figure 2 250 and a radial axis 252 are provided for reference. It should be understood that a radial axis is any axis perpendicular to the rotation axis 250.

[0029] The x-ray tube 200 includes a housing 202 having a low pressure enclosure 204 (eg, a vacuum enclosure) formed therein. It should be understood that low pressure enclosure means a relatively low pressure relative to atmospheric pressure. Thus, the pressure in the enclosure may be less than atmospheric pressure.

[0030] The x-ray tube 200 includes a liquid metal bearing assembly 205 having a rotating component 208 and a fixed component 206. In the illustrated embodiment, the rotating component 208 is a sleeve and the fixed component 206 is a shaft. However, embodiments in which the sleeve is fixed and the shaft rotates are envisioned. It should be understood that the motion represented by the "fixed" and "rotating" descriptors represents relative motion between the components. However, in certain use case examples, the x-ray tube may be integrated into a mobile structure. For example, in a CT imaging system use case, the x-ray tube may be integrated into a rotating gantry. Therefore, in a smaller scale frame of reference, the shaft is fixed relative to the sleeve, but in a larger scale frame of reference, the two components exhibit similar rotational motion in the gantry. However, in an alternative use case scenario, for a larger scale frame of reference, the x-ray tube may be integrated into a fixed structure. It should also be understood that in some cases, the liquid metal bearing assembly described in more detail herein may be deployed in an alternative type of system utilizing liquid metal bearings.

[0031] A rotor 218 and a stator 220 are also provided in the x-ray tube 200. The rotor 218 is coupled to the rotating component 208 and is designed to impart rotational motion thereto. The stator 220 is shown as being placed outside of the low voltage enclosure 204. However, other suitable stator locations are contemplated. In general, the rotor and stator may include windings, magnets, electrical connections, etc., which electromagnetically interact to provide a rotational motion between, for example, the rotor and the stator. Figure 1 The x-ray controller 110 is shown to generate rotor rotation upon receiving the control commands.

[0032] The x-ray tube 200 also includes an anode 210 and a cathode 212. The anode 210 is coupled to a rotating member 208, which can rotate the anode 210 during x-ray beam generation. The cathode 212 is part of a cathode assembly and can be controlled by a controller such as Figure 1 An x-ray controller 110 is shown receiving signals to generate an electron beam toward the surface of anode 210. When the electron beam from cathode 212 strikes anode 210, an x-ray beam 214 is generated. The x-rays are emitted and pass through an x-ray window 216 in housing 202.

[0033] Turning to the liquid metal bearing assembly 205, a plurality of liquid metal bearings may include the assembly. In the illustrated embodiment, the liquid metal bearing assembly 205 may include a liquid metal journal bearing 222 and a liquid metal thrust bearing 224, both of which may be supplied with liquid metal from a liquid metal pool, as described in reference to Figure 3 20. However, in other embodiments, component configurations with additional or alternative bearings may be used. The liquid metal journal bearing 222 is designed to support radial loads, and the liquid metal thrust bearing 224 is designed to support axial loads. In this way, the load on the sleeve (e.g., rotating component 208) can be managed to achieve efficient sleeve rotation.

[0034] Each of the bearings of the liquid metal bearing assembly 205 includes an interface 226 in which the liquid metal acts as a lubricant and also supports radial and axial loads. The thickness of the interface can be selected based on factors such as the type of liquid metal used in the bearing, manufacturing tolerances of the components, expected system operating temperatures, and the like. Thus, in one use case example, the thickness of the liquid metal interface can be approximately 5 micrometers (μm) to 40 μm. The thickness of the liquid metal interface of the liquid metal journal bearing 222 can be in a radial direction of the liquid metal bearing assembly 205 (e.g., relative to the radial axis 252), and the thickness of the liquid metal interface of the liquid metal thrust bearing 224 can be in a radial direction of the liquid metal bearing assembly 205 and in an axial direction parallel to the rotating axis 250. The liquid metal used as a working fluid in the bearing assembly may include gallium, tin, indium, combinations thereof, and the like. References herein Figures 3 to 9GEmbodiments of the described liquid metal bearing assemblies may use gallium as the liquid metal lubricant.

[0035] Figure 3 1 shows an embodiment of a liquid metal bearing assembly 300. In some examples, the liquid metal bearing assembly 300 can be used with Figure 2 The liquid metal bearing assembly 205 shown is similar or identical to the liquid metal bearing assembly 205. Therefore, features from the bearing assembly 205, and more broadly the x-ray tube 200, may be included in the liquid metal bearing assembly 300 and other liquid metal bearing assembly embodiments described herein. Figure 3 A coordinate system 301 is provided for reference. In one example, the y-axis can be the vertical axis (e.g., when the liquid metal bearing assembly 300 is mounted to an imaging system (such as the one described above with reference to FIG. Figure 1 In the case of the x-ray imaging system 100 described above, the x-ray source is parallel to the direction of gravity), the x-axis can be a transverse axis (eg, a horizontal axis), and the z-axis can be a longitudinal axis. However, in other examples, the axes can have other orientations.

[0036] The liquid metal bearing assembly 300 includes a rotating component, which may be referred to herein as a sleeve 302, and a stationary component, which may be referred to herein as a shaft 304. The sleeve 302 and the shaft 304 may be coupled so that the sleeve 302 can rotate relative to the shaft 304. Each of the sleeve 302 and the shaft 304 is provided with a structure that forms a liquid metal flow path when the liquid metal bearing assembly 300 is assembled, such as Figure 3 As shown (e.g., shaft 304 enclosed in sleeve 302). The liquid metal flow path may include one or more liquid metal pools 310, 312, 314 (e.g., lubricant pools), a pool 316, a gap 317, and one or more thrust bearing exhaust ports 318. The pools 310, 312, 314 may be machined as part of the sleeve 302 or formed with the sleeve 302 (e.g., machined, drilled) and positioned radially away from the centerline of the bearing. For example, the centerline of the bearing may be a central rotational axis 320, which is equivalent to Figure 2 The rotation axis is 250. Figures 4 to 8 Further details regarding the thrust bearing vent 318 are described.

[0037] The liquid metal pools 310, 312, 314 may extend annularly around the shaft 304. One or more of the liquid metal pools 310, 312, 314 may be positioned between the shaft 304 and the sleeve 302. The liquid metal pools 310, 312, 314 may be fluidly connected to the pool 316. The liquid metal pools 310, 312, 314 may hold a volume greater than the total fill volume of the pool 316 and the gap 317. For example, the combined fill volume may be between 2 g and 20 g, depending on the design of the bearing. For example, a conventional liquid metal pool may hold less than 2 g of gallium.

[0038] The liquid metal flow path including the liquid metal pools 310, 312, 314, the pool 316, and the gap 317 may have an annular configuration between the sleeve 302 and the shaft 304. One or more thrust bearing vents 318 may be periodically positioned around the interface between the sleeve and the shaft between the two liquid metal pools. The angled diameters (e.g., tapering) of the shaft 304 and sleeve 302 provide a narrowing of the width of the liquid flow path from the liquid metal pool 316 to the gap 317 (e.g., between the shaft 304 and the sleeve 302). Described in another way, at the liquid pool 316, the diameter of the shaft 304 can be increased relative to the diameter of the shaft 304 at the liquid metal liquid pool 312, and the diameter of the interior of the sleeve 302 can be reduced relative to the diameter of the interior of the sleeve 302 at the liquid metal liquid pool 312, thereby reducing the total width of the liquid metal flow path between the shaft 304 and the sleeve 302 in a direction from the first end 326 of the shaft toward the second end 328.

[0039] During assembly of the liquid metal bearing assembly 300, liquid metal (e.g., gallium) may be injected or otherwise inserted into the liquid metal pool 316. The liquid metal may be collected from the pool 316 to the intersection of the pool 316 and the gap 317. The width of the gap 317 may be less than the width of the liquid metal bead so that the liquid metal does not flow into the gap 317. The liquid metal bearing assembly 300 may be heated, and capillary forces may pull the liquid metal from the pool 316 into the gap 317. The liquid metal may thus coat the surface of the bearings (e.g., liquid metal journal bearings and / or liquid metal thrust bearings) of the liquid metal bearing assembly 300 to produce a force-bearing surface having a continuous layer of liquid metal extending between the sleeve 302 and the shaft 304. This may allow the sleeve 302 to rotate smoothly and uninterruptedly relative to the shaft 304, such as during operation of the x-ray tube to generate an x-ray beam, as described with reference to FIG. Figure 1 and Figure 2The liquid metal bearing assembly 300 may also include a seal located in the lower region 306 of the liquid metal bearing assembly 300, which may reduce the amount of liquid metal that leaks from the bearing. For example, the seal may be a rotary seal, a compression seal, etc. The seal may prevent liquid metal from leaking from the anode (such as the bearing assembly) in an axial direction (e.g., along the central rotation axis 320). Figure 2 Anode 210 shown in FIG. 2 flows away.

[0040] Go to Figure 4 , which shows a first exemplary embodiment 400 of a thrust bearing exhaust port 402 of a liquid metal bearing assembly. The thrust bearing exhaust port 402 is an axial hole disposed through a thrust flange 404 of the liquid metal bearing, intersecting a first pool of liquid metal 310 formed between a journal 406 and a thrust bearing 408, and extending to a second pool of liquid metal. The exemplary thrust bearing exhaust port 402 extends between the first pool of liquid metal 310 and the second pool of liquid metal 312, and has a first end 412 connected to a lowest point 410 (e.g., a point closest to the central rotational axis 320) of the first pool of liquid metal 310 and a second end 414 connected to the second pool of liquid metal 312. The contact point 412 between the thrust bearing exhaust port 402 and the pool of liquid metal 310 is located at the lowest point 410 to maximize the removal of gas trapped in the pool of liquid metal 310. The surface tension and centrifugal effect of rotating the sleeve will ensure that the gas trapped in the first liquid metal pool 310 will be completely exhausted through the thrust bearing exhaust port 402, and no residual bubbles will remain in the liquid metal pool 310 after the rotation speed reaches about 10 Hz.

[0041] Figure 4 The centerline 416 of the thrust bearing exhaust port 402 of the exemplary embodiment 400 is positioned parallel to the central rotational axis 320 and therefore has a relative angle of 0 degrees. In the illustrated example, the angle is approximately 8.5 degrees. In other examples, the angle can be between 0 and 15 degrees. The exemplary thrust bearing exhaust port 402 has a constant diameter, which can be between 0.1 mm and 2.5 mm, but preferably between 0.5 mm and 1.5 mm. The exemplary thrust bearing exhaust port 402 can be formed using any suitable machining method, including drilling or laser drilling.

[0042] Figure 5A second exemplary embodiment 500 of a thrust bearing vent 502 in a liquid metal bearing assembly is depicted. The thrust bearing vent 502 is a conical hole disposed through the thrust flange 404 of the liquid metal bearing, intersecting the first pool of liquid metal 310 formed between the journal 406 and the thrust bearing 408, and extending to the second pool of liquid metal 312. The exemplary thrust bearing vent 502 is substantially symmetrical about a central axis 504, except for the opening 506 at the first pool of liquid metal 310. Additionally, the central axis 504 of the thrust bearing vent 502 of the illustrated embodiment is parallel to the central axis 320 of the bearing assembly. However, in other embodiments, the thrust bearing vent 502 may be asymmetrical and / or may have a central axis positioned at an angle relative to the central axis of the bearing assembly.

[0043] Similar to thrust bearing exhaust port 402, Figure 5 The thrust bearing exhaust port 502 is connected to the first liquid metal pool 310 at the lowest point 410 of the pool 310. In the example shown, the conical thrust bearing exhaust port 502 has a first end 508 that tapers to a point and a second end 510 that is connected to the second liquid metal pool 312. The thrust bearing exhaust port 502 contacts the first liquid metal pool 310 along the top of the inclined surface of the conical hole. The diameter of the contact point between the thrust bearing exhaust port 502 and the first liquid metal pool 310 is smaller than the diameter of the contact point between the thrust bearing exhaust port 502 and the second liquid metal pool 312. For example, the diameter of the thrust bearing exhaust port 502 at the contact point of the first liquid pool 310 can be 0.5 mm, while the diameter at the contact point of the second liquid pool can be 1.5 mm. Other suitable sizes can be used, such as any diameter between 0.1 mm and 2.5 mm. The exemplary thrust bearing exhaust port 502 can be manufactured using any suitable machining method, including drilling or laser drilling.

[0044] This change in diameter results in an angle of departure from the contact point at the first liquid metal pool 310 that is greater than 0 degrees, resulting in a lower capillary force in the direction of the opening 510 at the second liquid metal pool 312. The greater the departure angle, the greater the reduction in capillary force. The lower capillary force of the exemplary embodiment 500 allows gas to easily escape from the first liquid metal pool 310 while creating an enhanced sealing effect that prevents gas from returning from the second liquid metal pool 312 to the first liquid metal pool 310.

[0045] Figure 6A third exemplary embodiment 600 of a thrust bearing exhaust port 602 in a liquid metal bearing assembly 300 is depicted. The thrust bearing exhaust port 602 is disposed through the thrust flange 404 of the liquid metal bearing 300, intersects the first liquid metal pool 310 formed between the journal 406 and the thrust bearing 408, and extends to the second liquid metal pool 312. Similar to Figure 4 and Figure 5 The thrust bearing exhaust port 602 has a first end 604 connected to the first liquid metal pool 310 at the lowest point 410 and a second end 606 connected to the second liquid metal pool 312 .

[0046] Figure 6 The exemplary thrust bearing vent 602 includes a first portion 608 having a constant diameter and a second portion 610 that flares or chamfers outward from the first portion. In the example shown, the flared portion 610 is connected to the second liquid metal bearing pool 312. In addition, the second portion 610 in the example shown is shorter than the first portion 608, but in other examples, the second portion 610 can be equal to or longer than the first portion 608 in length. The diameter of the contact point between the thrust bearing vent 602 and the first liquid metal pool 310 is smaller than the diameter of the contact point between the thrust bearing vent 602 and the second liquid metal pool 312. For example, the diameter of the thrust bearing vent 602 at the contact point of the first pool 310 can be 0.5 mm, while the diameter at the contact point of the second pool 312 can be 1.5 mm. Other suitable sizes can be used, such as any diameter between 0.1 mm and 2.5 mm. The exemplary thrust bearing vent 602 can be manufactured using any suitable machining method, including drilling or laser drilling. The change in diameter between the first portion 608 and the end 606 of the second portion 610 (where the thrust bearing exhaust port 602 contacts the second liquid metal pool 312) reduces capillary action and provides a smooth and even seal with the combination of the first portion 608 and the second portion 610. Figure 5 The sealing capability of thrust bearing vent 602 is increased in a similar manner as described for thrust bearing vent 502. Thus, Figure 5 and Figure 6 The exemplary thrust bearings 502 and 602 create a one-way capillary valve for gas to flow from the first liquid reservoir 310 to the second liquid reservoir 312 .

[0047] Figure 7 A fourth exemplary embodiment 700 of a thrust bearing exhaust port 702 of a liquid metal bearing assembly 300 is depicted. The thrust bearing exhaust port 702 is disposed through the thrust flange 404 of the liquid metal bearing 300, intersects the first liquid metal pool 310 formed between the journal 406 and the thrust bearing 408, and extends to the second liquid metal pool 312. Similar to Figures 4 to 6The thrust bearing exhaust port 702 has a first end 704 connected to the first liquid metal pool 310 at the lowest point 410 and a second end 706 connected to the second liquid metal pool 312 .

[0048] exist Figure 7 In the example shown, the thrust bearing exhaust port 702 has a constant diameter and is positioned so that the central axis 708 of the thrust bearing exhaust port 702 is angled relative to the central axis 320 of the bearing assembly 300. This achieves a bidirectional capillary action. However, the angle must be such that the end of the thrust bearing exhaust port 702 connected to the second liquid metal pool 312 is at a smaller radius from the central rotation axis 320 to ensure that the gas is not trapped in the thrust bearing exhaust port 702. In addition, the angle should be between 0 degrees and 45 degrees to achieve the desired capillary effect. In some examples, the angle is preferably less than 10 degrees. The exemplary thrust bearing exhaust port 702 has a constant diameter, which can be between 0.1 mm and 2.5 mm, but preferably between 0.5 mm and 1.5 mm. The exemplary thrust bearing exhaust port 402 can be formed using any suitable processing method, including drilling or laser drilling.

[0049] Figure 8 A fifth exemplary embodiment 800 of a thrust bearing vent 802 of the illustrated liquid metal bearing assembly is depicted. The thrust bearing vent 802 is a conical hole disposed through a thrust flange of the liquid metal bearing, intersecting a first pool of liquid metal 310 formed between the journal 406 and the thrust bearing 408, and extending to a second pool of liquid metal. The exemplary thrust bearing vent 802 is substantially symmetrical about a central axis. Additionally, a central axis 804 of the thrust bearing vent 802 of the illustrated embodiment is positioned at an angle relative to a central axis 320 of the bearing assembly 300. However, in other embodiments, the thrust bearing vent 802 may be asymmetrical and / or may have a central axis 804 positioned parallel to the central axis of the bearing assembly.

[0050] Similar to thrust bearing exhaust ports 402, 502, 602, 702, Figure 8 The thrust bearing vent 802 of FIG. 804 connects a first end 804 to the first pool of liquid metal 310 at the lowest point of the pool 310 and a second end 806 to the second pool of liquid metal 312. In the example shown, the conical thrust bearing vent 802 tapers toward the second end 806, which connects the thrust bearing vent 802 to the second pool of liquid metal 312. Figure 8In the embodiment 800, the diameter of the second end 806 is smaller than the diameter of the first end 804. For example, the diameter of the thrust bearing vent 802 at the contact point of the second liquid pool 312 can be 0.5 mm, and the diameter at the contact point of the first liquid pool 310 can be 1.5 mm. Other suitable sizes can be used, such as any diameter between 0.1 mm and 2.5 mm. The exemplary thrust bearing vent 802 can be manufactured using any suitable machining method, including drilling or laser drilling.

[0051] This change in diameter results in a deviation angle from the contact point at the second liquid metal pool 310 greater than 0 degrees, resulting in a lower capillary force in the direction of the opening at the first liquid metal pool 310, similar to the bonding Figure 5 However, because the larger diameter is at the end 804 connected to the first pool of liquid metal 310, the flow is reversed and flows from the second pool of liquid metal 312 to the first pool of liquid metal 310 instead.

[0052] The exemplary thrust bearing exhaust port 802 has a centerline 808 that is angled relative to the central axis 320 of the bearing assembly. The angle should be between 0 and 45 degrees to achieve the desired capillary effect. In some examples, the angle is preferably less than 10 degrees. The angle must be such that the end of the thrust bearing exhaust port 802 connected to the second liquid metal pool 312 is at a small radius from the centerline to ensure that gas is not trapped in the thrust bearing exhaust port 802.

[0053] FIG. 9A to FIG. 9G Depicted are examples of how exemplary thrust bearing vents 318, 402, 502, 602, 702, 802 may be positioned radially about the axis of the bearing assembly 300. To simplify the drawings, the general reference numeral 318 will be used to refer to any of the various embodiments of thrust bearing vents discussed herein. Figure 3 A coordinate system 301 in FIG. 3 is depicted with the illustrated example to provide orientation of thrust bearing exhaust ports 318, 402, 502, 602, 702, 802. One or more thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 may be used with the exemplary bearing assembly 300. If more than one thrust bearing exhaust port 318, 402, 502, 602, 702, 802 is implemented, the number of thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 is preferably an even number (e.g., 2, 4, or 6), and the thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 are preferably in pairs. However, the thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 may be positioned symmetrically or asymmetrically around an axis.

[0054] Additionally, the pressure at different locations of the thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 may be different due to pressure variations (e.g., pressure gradients) from the top 904 to the bottom of the bearing assembly 300. The pressure gradients may be caused by gravity and / or body loads of the frame in the y-direction. For example, Fig. 9A The illustrated embodiment 902 depicts four radially equally spaced 90 degree apart thrust bearing exhaust ports 318, 402, 502, 602, 702, 802. The thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 that are closer to the top 904 of the bearing assembly 300 will have a different pressure than the thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 that are located near the horizontal center of the bearing assembly, and will have a different pressure than the thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 that are located near the bottom 906 of the bearing assembly.

[0055] Fig. 9B An embodiment 908 is depicted having two thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 equally spaced 180 degrees apart in the horizontal direction. The bearing exhaust ports 318, 402, 502, 602, 702, 802 in the exemplary embodiment 908 are symmetrical about the vertical axis. Fig. 9B The thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 will have approximately the same pressure. In some examples, Fig. 9B A preferred design is depicted.

[0056] Fig. 9C An embodiment 910 is depicted having two thrust bearing vents 318, 402, 502, 602, 702, 802 radially equidistantly spaced 180 degrees apart in the vertical direction. The bearing vents 318, 402, 502, 602, 702, 802 in the exemplary embodiment 908 are symmetrical about a horizontal axis. Fig. 9C The thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 will have different pressures.

[0057] Fig.9D An embodiment 912 is depicted having two thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 that are positioned approximately 60 degrees apart, with each thrust bearing exhaust port positioned approximately 30 degrees on each side of the vertical axis. The bearing exhaust ports 318, 402, 502, 602, 702, 802 in exemplary embodiment 908 are symmetrical about the vertical axis. Fig.9DThe thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 are located closer to the top 904 of the bearing assembly and will have approximately the same pressure.

[0058] Fig.9E An embodiment 914 is depicted having two thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 that are positioned approximately 60 degrees apart, with each thrust bearing exhaust port positioned approximately 30 degrees on each side of the vertical axis. The bearing exhaust ports 318, 402, 502, 602, 702, 802 in exemplary embodiment 910 are symmetrical about the vertical axis. Fig.9E The thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 are located closer to the bottom 906 of the bearing assembly and will have approximately the same pressure.

[0059] Fig.9F An embodiment 916 is depicted having one thrust bearing exhaust port 318, 402, 502, 602, 702, 802 positioned at the bottom of the bearing assembly 300. In embodiments including only a single thrust bearing exhaust port 318, 402, 502, 602, 702, 802, the preferred location of the thrust bearing exhaust port 318, 402, 502, 602, 702, 802 is at the bottom 906 of the bearing assembly 300, however any other location of the thrust bearing exhaust port 318, 402, 502, 602, 702, 802 about the shaft is also suitable.

[0060] Figure 9G An embodiment 918 is depicted having two thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 positioned approximately 180 degrees apart, with each thrust bearing exhaust port positioned approximately 30 degrees on each side of the vertical axis. However, Figure 9G The exemplary thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 of the embodiment 910 of the embodiment 910 are positioned at opposite ends of the vertical axis, resulting in an asymmetric arrangement with respect to the vertical axis and the horizontal axis. That is, one of the thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 is positioned near the top 904, and one of the thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 is positioned near the bottom 906. Fig. 9C The thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 will have different pressures.

[0061] Although some exemplary embodiments of the arrangement of the thrust bearing exhaust ports 402, 502, 602, 702, 802 have been described, these examples are non-limiting. That is, other variations including additional thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 and / or thrust bearing exhaust ports 318, 402, 502, 602, 702, 802 placed at different orientations or angles may also be implemented.

[0062] Figures 2 to 9G An exemplary configuration of the relative positioning of various components is shown. In at least one example, if it is shown as being in direct contact or directly coupled to each other, such elements may be referred to as being in direct contact or directly coupled, respectively. Similarly, in at least one example, the elements shown as being adjacent or adjacent to each other may be adjacent or adjacent to each other, respectively. For example, components placed in coplanar contact with each other may be referred to as being in coplanar contact. For another example, in at least one example, elements positioned to be spaced apart from each other and having only space therebetween without other components may be described and referenced as such. For another example, elements shown as being located above / below each other, located on opposite sides of each other, or located on the left / right side of each other may be described and referenced as such relative to each other. In addition, as shown in the figure, in at least one example, the topmost element or the point of the element may be referred to as the "top" of the component, and the bottommost element or the point of the element may be referred to as the "bottom" of the component. As used herein, top / bottom, upper / lower, above / below may be relative to the vertical axis of the figure, and may be used to describe the position of the elements relative to each other in the figure. Thus, in one example, the element shown as being located above other elements is positioned vertically above other elements. For another example, the shapes of elements depicted in the figures may be referred to as having those shapes (e.g., such as being rounded, straight, planar, curved, rounded, chamfered, angled, etc.). Furthermore, in at least one example, elements shown as intersecting each other may be referred to as intersecting elements or intersecting each other. Additionally, in one example, elements shown as being within another element or shown as being outside another element may be described and referred to as such.

[0063] As used herein, the elements or steps listed in the singular and beginning with the word "one" or "an" should be understood as not excluding a plurality of said elements or steps, unless such exclusion is explicitly stated. In addition, the reference to "one embodiment" of the present invention is not intended to be interpreted as excluding the existence of additional embodiments that also include the cited features. In addition, unless explicitly stated to the contrary, "comprising", "including" or "having" an embodiment of an element or multiple elements with a specific characteristic may include additional such elements that do not have the characteristic. The terms "including" and "in..." are used as the concise language equivalents of the corresponding terms "including" and "wherein". In addition, the terms "first", "second" and "third" etc. are only used as marks, and are not intended to impose numerical requirements or specific positional order on their objects.

[0064] This written description uses examples to disclose the invention, including the best mode, and also to enable a person skilled in the relevant art to practice the invention, including making and using any devices or systems and performing any included methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to a person skilled in the art. Such 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 insignificant differences from the literal language of the claims.

Claims

1. A liquid metal bearing assembly, comprising: a first liquid metal pool; a second liquid metal pool; and a thrust bearing exhaust port extending between the first liquid metal pool and the second liquid metal pool to discharge gas between the first liquid metal pool to the second liquid metal pool, wherein a first end of the thrust bearing exhaust port is connected to the first liquid metal pool at a point where the first liquid metal pool is closest to a central axis of the liquid metal bearing assembly.

2. The liquid metal bearing assembly according to claim 1, further comprising a rotating component and a fixed component, wherein the rotating component at least partially circumferentially surrounds the fixed component, and the first liquid metal pool and the second liquid metal pool are positioned between the rotating component and the fixed component.

3. The liquid metal bearing assembly of claim 1, wherein the thrust bearing exhaust port has a constant diameter.

4. The liquid metal bearing assembly of claim 1, wherein the thrust bearing vent has a first diameter at a point of contact with the first pool of liquid metal and a second diameter at a point of contact with the second pool of liquid metal.

5. The liquid metal bearing assembly according to claim 4, wherein the thrust bearing exhaust port is conical in shape.

6. The liquid metal bearing assembly of claim 4, wherein the thrust bearing exhaust port has a flared portion.

7. The liquid metal bearing assembly of claim 1 further comprising at least one additional thrust bearing exhaust port.

8. The liquid metal bearing assembly of claim 7, wherein the thrust bearing exhaust port and the at least one additional thrust bearing exhaust port are equally spaced radially around the liquid metal bearing assembly.

9. The liquid metal bearing assembly of claim 7, wherein the thrust bearing exhaust port and the at least one additional thrust bearing exhaust port are positioned symmetrically about an axis of the liquid metal bearing assembly.

10. The liquid metal bearing assembly of claim 7, wherein the thrust bearing exhaust port and the at least one additional thrust bearing exhaust port are asymmetrically positioned about an axis of the liquid metal bearing assembly.

11. An x-ray source, comprising: cathode; An anode having a rotating component, wherein the rotating component is rotated by a liquid metal bearing assembly having a rotating component circumferentially surrounding a fixed component, the anode further comprising: a first liquid metal pool; a second pool of liquid metal; and a thrust bearing exhaust port extending between the first liquid metal pool and the second liquid metal pool to discharge gas between the first liquid metal pool to the second liquid metal pool, wherein a first end of the thrust bearing exhaust port is connected to the first liquid metal pool at a point where the first liquid metal pool is closest to a central axis of the liquid metal bearing assembly.

12. The x-ray source of claim 11, wherein the first and second pools of liquid metal are positioned between the rotating component and the stationary component.

13. The x-ray source of claim 11, wherein the thrust bearing exhaust port has a constant diameter.

14. The x-ray source of claim 11, wherein the thrust bearing exhaust port has a first diameter at a point of contact with the first pool of liquid metal and a second diameter at a point of contact with the second pool of liquid metal.

15. The x-ray source of claim 14, wherein the thrust bearing exhaust port is conical in shape.

16. The x-ray source of claim 14, wherein the thrust bearing exhaust port has a flared portion.

17. The x-ray source of claim 11 further comprising at least one additional thrust bearing exhaust port.

18. The x-ray source of claim 17, wherein the thrust bearing exhaust port and the at least one additional thrust bearing exhaust port are equally spaced radially around the liquid metal bearing assembly.

19. The x-ray source of claim 17, wherein the thrust bearing exhaust port and the at least one additional thrust bearing exhaust port are positioned symmetrically about an axis of the liquid metal bearing assembly.

20. The x-ray source of claim 17, wherein the thrust bearing exhaust port and the at least one additional thrust bearing exhaust port are asymmetrically positioned about an axis of the liquid metal bearing assembly.

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