Systems and methods for liquid metal bearing assembly

Abstract

To provide systems and methods for a liquid metal bearing assembly.SOLUTION: A liquid metal bearing assembly (300) includes a channel (314) fluidly coupling a liquid metal reservoir (312) to a gap (316) between a sleeve (302) and a shaft (304). The channel comprises a first section (314a) sloped at a first angle, and a second section (314b) sloped at a second angle, where the first angle is different from the second angle. A curved transition section (458) is positioned between the first section and the second section.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the subject matter disclosed herein relate to systems having liquid metal bearing assemblies and methods of assembling liquid metal bearing assemblies. [Background technology]

[0002] Liquid metal bearings are used in a variety of applications because they have a longer life span and can more effectively manage thermal loads than roller bearings. For example, some X-ray sources and tubes utilize liquid metal bearings, at least in part due to their durability and thermodynamic properties. However, asymmetric liquid metal distribution and gas formation at the bearing's liquid metal interface can occur within the bearing. Summary of the Invention

[0003] In one embodiment, a liquid metal bearing assembly is provided comprising: a flow passage fluidly coupling a liquid metal reservoir to a gap between a sleeve and a shaft; and the flow passage having a first portion inclined at a first angle and a second portion inclined at a second angle, the first angle being different from the second angle, and a curved transition portion being disposed between the first portion and the second portion.

[0004] The above and other advantages and features of the present specification will become readily apparent from the following detailed description, either alone or when considered in conjunction with the accompanying drawings. It should be understood that the above summary is provided to introduce in a simplified form a selection of concepts that are further described in the detailed description. It is not intended to identify key features or essential characteristics of the claimed subject matter, the scope of which is defined solely by the claims that follow the detailed description. Moreover, the claimed subject matter is not limited to implementations that solve the disadvantages noted above or in any part of this disclosure. [Brief description of the drawings]

[0005] The present disclosure will be better understood upon reading the following description of non-limiting embodiments, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a block schematic diagram of an exemplary X-ray imaging system in accordance with an embodiment. [Diagram 2] FIG. 2 is a pictorial diagram illustrating a portion of an X-ray source in accordance with an embodiment. [Diagram 3] 1 illustrates a liquid metal bearing assembly according to an embodiment. [Figure 4A] FIG. 4A is a detailed view of a portion of the liquid metal bearing assembly shown in FIG. 3, including the liquid metal reservoir. [Figure 4B] FIG. 4B shows a first embodiment of a shaft for the liquid metal bearing assembly shown in FIGS. 3 and 4A. [Diagram 5] 13 illustrates another shaft of a liquid metal bearing assembly according to an embodiment. [Figure 6] 13 illustrates another shaft of a liquid metal bearing assembly according to an embodiment. [Figure 7] 13 illustrates an additional embodiment of a shaft of a liquid metal bearing assembly. [Figure 8] FIG. 4 is a detailed view of a portion of the liquid metal bearing assembly shown in FIG. 3, including a pinning feature, according to an embodiment. [Figure 9] 9A and 9B show a second embodiment of a sleeve for the liquid metal bearing assembly shown in FIG. 3, according to an embodiment. [Figure 10] 13 shows a second embodiment of a sleeve of a liquid metal bearing assembly according to an embodiment. [Figure 11] 11A, 11B and 11C show additional embodiments of liquid metal bearing assemblies according to embodiments. [Figure 12] 1A-1D show various views of a liquid metal bearing assembly including the insertion of a shaft into a sleeve, according to an embodiment. [Figure 13]1 is an exemplary method of assembling a liquid metal bearing assembly, according to an embodiment. [Figure 14] 13 illustrates an additional embodiment of a shaft of a liquid metal bearing assembly. [Figure 15] 13 illustrates an additional embodiment of a shaft of a liquid metal bearing assembly. [Figure 16] 13 illustrates an additional embodiment of a shaft of a liquid metal bearing assembly. [Figure 17] 1 illustrates an additional embodiment of a liquid metal bearing assembly. [Figure 18] 13A-13C illustrate additional examples of pinning features for liquid metal bearing assemblies. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] The following description relates to various embodiments of a system (e.g., an x-ray imaging system) and a liquid metal bearing assembly deployed therein. The liquid metal bearing allows a desired level of liquid metal filling precision to be achieved in the system. It is believed that the outcome of liquid metal filling precision is reduced gas suspended in the liquid metal and, in some cases, a more uniform distribution of the liquid metal at the bearing interface. As a result, a reduced coefficient of friction is achieved, improving the durability and life of the bearing.

[0007] The disclosed liquid metal bearing assembly includes a shaft and a sleeve having a gap therebetween, and a liquid metal, such as gallium, can be introduced into the gap using capillary action. The present disclosure addresses current challenges in the manufacture of liquid metal bearings by promoting good capillary wettability and retention of liquid metal. This is accomplished by introducing a gradual transition (e.g., sharp chamfer transitions) from the gallium reservoir to the gap. The gradual transition reduces the difficulty of aligning the shaft and sleeve and allows for self-alignment during the assembly process, thereby improving yield and reducing capacity constraints during manufacturing. As another example, the shaft and sleeve configuration can reduce reliance on lubricants used during assembly that can contaminate the gallium and inhibit its lubricating ability. Additionally, a smooth transition is used on the outer surface of the thrust bearing to encourage full wetting with the liquid gallium. A strategically placed pinning feature reduces the amount of gallium that can undesirably flow outside the journal surface to the lower rotating seal or reservoir within the bearing, thus allowing capillary forces within the gap to hold the gallium there.

[0008] The X-ray imaging system is shown in FIG. 1 and includes an X-ray source (such as an X-ray tube) configured to generate X-rays, and an X-ray controller. One embodiment of an X-ray source is shown in FIG. 2, where the X-ray source is configured with a liquid metal bearing to provide anode rotation. FIG. 3 shows a first embodiment of a liquid metal bearing assembly, and FIG. 4A shows a detailed view of a flow passage fluidly coupling a liquid metal reservoir to a gap of the liquid metal bearing assembly. FIG. 4B is a detailed view of a shaft of the liquid metal bearing assembly including angled surfaces forming the flow passage of FIG. 4A. FIG. 5 is a detailed view of another shaft of the liquid metal bearing assembly. FIG. 6 is a detailed view of another shaft of the liquid metal bearing assembly different from the shaft shown in FIG. 5. FIG. 7 shows an additional embodiment of a shaft of the liquid metal bearing assembly having a different angled surface within the dimensions of the liquid metal bearing assembly. FIG. 8 is a detailed view of a cross section of the liquid metal bearing assembly of FIG. 3 including a pinning feature. 9A and 9B show first and second views, respectively, of the sleeve of the liquid metal bearing of FIG. 3. Additional configurations of the sleeve are shown in FIG. 10. FIGS. 11A, 11B, and 11C show additional embodiments of the liquid metal bearing assembly. FIG. 12 shows an example of assembly of the liquid metal bearing assembly including shaft insertion into the sleeve. FIG. 13 shows a method of operation of a system including the liquid metal bearing assembly. FIGS. 14, 15, and 16 show additional embodiments of the shaft of the liquid metal bearing assembly, each embodiment having a different angled surface within the dimensional range of the liquid metal bearing assembly. FIG. 17 shows another example of the liquid metal bearing assembly. In this example, the flow passages and pinning features may be in the opposite orientation, such that the fill port, the angle forming the liquid metal reservoir, and the entrance to the gap are on the seal side of the liquid metal bearing and the pinning feature is on the opposite end of the shaft with the sleeve. FIG. 18 shows additional examples of pinning features of the liquid metal bearing assembly.

[0009] 2-10, 12, and 14-16 are drawn to scale, but other relative dimensions may be used. FIGS. 2-10, 12, and 14-18 show example configurations with relative positional relationships of various components. When shown in direct contact with one another or in direct connection, such elements may, at least in one example, be referred to as being in direct contact with one another or in direct connection with one another. Similarly, elements shown in succession or adjacent to one another may, at least in one example, be in succession or adjacent to one another. As an example, components laid out in surface contact with one another may be referred to as being in surface contact. As another example, elements placed apart from one another, with only space between them and no other components present, at least in one example, may be so referred to. As yet another example, elements shown above / below one another, opposite one another, or to the left / right of one another may be so referred to with respect to one another. Additionally, as shown in the figures, in at least one example, the topmost element or point of an element may be referred to as the "top" of the component, and the bottommost element or point of an element may be referred to as the "bottom" of the component. As used herein, top / bottom, upper / lower, above / below are relative to the vertical axis of the figure and may be used to describe the positional relationship of the elements of the figure to one another. Thus, elements shown above other elements are, in one example, positioned vertically above the other elements. As yet another example, the shapes of elements depicted in the figures may be referred to as having those shapes (e.g., circular, straight, planar, curved, rounded, chamfered, angled, or the like). Additionally, elements shown to intersect with one another may, in at least one example, be referred to as intersecting elements or elements intersecting one another.Additionally, elements illustrated within other elements or elements illustrated outside other elements may be referred to as such by way of example.

[0010] The liquid metal bearing assembly includes a liquid metal interface disposed between a stationary component and a rotating component. The rotating component includes a liquid metal reservoir designed to contain the liquid metal and disposed radially inward from the liquid metal interface. The rotating component further includes a liquid metal passage extending between the liquid metal reservoir and the liquid metal interface. The rotating component may include a non-wetting surface within the liquid metal passage.

[0011] Before further describing the liquid metal bearing assembly for machinability and liquid metal introduction, an exemplary X-ray imaging system in which the liquid metal bearing assembly may be implemented is shown. FIG. 1 shows an X-ray imaging system 100 for generating X-rays. The X-ray imaging system 100 is configured in FIG. 1 as an X-ray imaging system, which may be a computed tomography (CT) imaging system, a radiography imaging system, a fluoroscopy imaging system, a mammography imaging system, an interventional imaging system, a tomography system, etc. However, the X-ray imaging system 100 may be applied outside the fields of imaging diagnosis and medical equipment. For example, the X-ray imaging system 100 may be deployed in crystallography systems, security scanners, industrial scanners, x-ray photography systems, and so on. In an example of an X-ray imaging system, the X-ray imaging 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 present within the body, such as an implant, a stent, and / or a contrast agent.

[0012] The X-ray imaging system 100 may include a collector assembly having at least one X-ray source 104, such as an X-ray tube, configured to generate and project a beam of X-ray radiation 106. Specifically, in the illustrated embodiment, the X-ray source 104 is configured to project the beam of X-ray radiation 106 through the subject 102 toward a detector array 108. In some system configurations, the X-ray source 104 may project a cone-shaped beam of X-ray radiation collimated to lie within an XYZ plane of a Cartesian coordinate system. However, other beam profiles and / or systems that omit a detector array are also contemplated. Each detector element of the array generates a separate electrical signal that is a measure of the X-ray beam attenuation at the detector location.

[0013] 1 depicts only a single x-ray source 104 and detector array 108, in certain embodiments, multiple x-ray sources and / or detectors may be employed to project and detect multiple beams of x-ray radiation. For example, in a CT application, multiple detectors may be used in parallel with the x-ray source to obtain projection data at different energy levels corresponding to the subject.

[0014] The X-ray imaging system 100 may further include an X-ray controller 110 configured to provide power and timing signals to the X-ray source 104. It will be appreciated 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 to digital signals for subsequent processing.

[0015] 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 commands and / or scanning parameters, for example, via an operator console 116 operably coupled to the computing device 112. The operator console 116 may include a keyboard, a touch screen, and / or other suitable input device that allows an operator to specify commands and / or scanning parameters.

[0016] 1, multiple operator consoles may be included in the radiography system 100, e.g., for inputting or outputting system parameters, requesting examinations, plotting data, and / or viewing images. Additionally, in certain embodiments, the radiography system 100 may be coupled to multiple displays, printers, workstations, and / or similar devices, e.g., located either locally or remotely and connected via wired and / or wireless networks. In one embodiment, the display 120 is in electronic communication with the computing device 112 and is configured to display a graphical interface showing system parameters, control settings, imaging data, etc.

[0017] In one example, computing device 112 stores data on storage device 118. Storage device 118 may include, for example, a hard disk 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.

[0018] Additionally, the computing device 112 provides commands to the X-ray controller 110 and other system components to control system operations such as X-ray beam formation, data acquisition and / or processing. Thus, in certain embodiments, the computing device 112 controls system operations based on operator input. In particular, the computing device 112 can use operator-supplied and / or system-defined commands and parameters to operate the X-ray controller 110, which can control the X-ray source 104. In this manner, the intensity and timing of X-ray beam generation can be controlled. It will also be appreciated that the rotational speed of a sleeve within the X-ray source is regulated by the computing device 112 in conjunction with the X-ray controller 110. The sleeve may be a rotating element of a liquid metal bearing assembly, as described in more detail herein.

[0019] Various methods and processes may be stored as executable instructions in non-transient memory on a computing device (or controller) in X-ray imaging system 100. In one embodiment, X-ray controller 110 may include the executable instructions in non-transient memory and may apply the methods to control X-ray source 104. In another embodiment, computing device 112 may include the instructions in non-transient memory and at least partially relay the instructions to X-ray controller 110 to adjust the X-ray source output.

[0020] FIG. 2 illustrates a detailed embodiment of a portion of an X-ray source, such as an X-ray tube 200. The X-ray tube 200 illustrated in FIG. 2 serves as an example of the X-ray source 104 depicted in FIG. 1. Thus, the X-ray source illustrated in FIG. 2, as well as other X-ray source embodiments described herein, can include functional and / or structural features from the X-ray source 104 illustrated in FIG. 1, or vice versa. Additionally, alternative embodiments that combine features from one or more systems are also contemplated. A rotation axis 250 and a radial axis 252 are provided in FIG. 2 for reference. It will be understood that a radial axis is any axis that is perpendicular to the rotation axis 250.

[0021] The x-ray tube 200 includes a housing 202 having a low pressure enclosure 204 (e.g., a vacuum enclosure) formed therein. It will be appreciated that a low pressure enclosure refers to a relatively low pressure relative to atmospheric pressure. Thus, the pressure within the enclosure may be less than atmospheric pressure.

[0022] The X-ray tube 200 includes a liquid metal bearing assembly 205 having a rotating member, here a rotational component 208, and a stationary member, here a stationary component 206. In one example, the rotating component 208 and the stationary component 206 can include wetted and non-wetted surfaces. In the illustrated embodiment, the rotating component 208 is a sleeve and the stationary component 206 is a shaft. However, embodiments in which the sleeve is stationary and the shaft rotates are also contemplated. It will be understood that the motion denoted by the descriptors stationary and rotational denote the relative motion between the components. However, in some applications, the X-ray tube may be incorporated into a moving structure. For example, in a CT imaging system application, the X-ray tube may be incorporated into a rotating gantry. Thus, in a small scale reference frame, the shaft is stationary relative to the sleeve, but in a large scale reference frame, both components exhibit similar rotational motion within the gantry. However, in other usage scenarios, the x-ray tube may be integrated into a structure that is stationary relative to a larger scale reference frame, and it will be appreciated that the liquid metal bearing assemblies described in detail herein may, in some cases, be deployed in other types of systems that utilize liquid metal bearings.

[0023] The x-ray tube 200 is also provided with a rotor 218 and a stator 220. The rotor 218 is coupled to the rotating component 208 to impart rotational motion thereto. The stator 220 is shown disposed outside the low-pressure enclosure 204; however, other suitable stator locations are contemplated. Typically, the rotor and stator may include windings, magnets, electrical connections, etc., and interact electromagnetically to produce rotor rotation that is responsive to receiving control commands, for example, from the x-ray controller 110 shown in FIG. 1.

[0024] The x-ray tube 200 further includes an anode 210 and a cathode 212. The anode 210 is part of an anode assembly. The anode 210 is coupled to and supported by a rotating part 208, which can impart rotation of the anode 210 during generation of the x-ray beam. The cathode 212 is part of a cathode assembly and can receive a signal from a controller, such as the x-ray controller 110 shown in FIG. 1, to generate an electron beam directed at a surface of the anode 210. When the electron beam from the cathode 212 strikes the anode 210, an x-ray beam 214 is generated. The x-rays are emitted through an x-ray window 216 in the housing 202.

[0025] Turning to the liquid metal bearing assembly 205, the assembly 205 includes a plurality of liquid metal bearings. 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. 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 manner, the load on the sleeve (e.g., rotating component 208) may be managed to provide efficient sleeve rotation.

[0026] Each bearing of the liquid metal bearing assembly 205 includes an interface 226 where the liquid metal acts as a lubricant and also supports radial and axial loads. The thickness of the interface may be selected based on factors such as the type of liquid metal used in the bearing, the manufacturing tolerances of the components, and the expected system operating temperature. Thus, in one use case, the thickness of the liquid metal interface is on the order of 5 microns (μm) to 40 microns (μm). The thickness of the liquid metal interface of the liquid metal journal bearing 222 may be in the direction of the radial axis 252, and the thickness of the liquid metal interface of the liquid metal thrust bearing 224 may be in the direction of the radial axis 252 and in the direction of the axis of rotation 250. The liquid metal used as the working fluid of the bearing assembly may include gallium, tin, indium, combinations thereof, and the like. The liquid metal bearing assembly embodiments described herein with respect to FIGS. 3-11 may use gallium as the liquid metal lubricant.

[0027] FIG. 3 illustrates an embodiment of a liquid metal bearing assembly 300. In some examples, the liquid metal bearing assembly 300 may be similar or the same as the liquid metal bearing assembly 205 depicted in FIG. 2. Thus, features from the liquid metal bearing assembly 205, and more generally features of the X-ray tube 200, may be included in the liquid metal bearing assembly 300 as well as in other liquid metal bearing assembly embodiments described herein. An axis 399 is provided in FIG. 3, as well as in FIGS. 4A-6, 8-10, and 12 for comparison purposes. In the illustrated example, the y-axis is the vertical axis, the x-axis is the transverse axis (e.g., horizontal axis) perpendicular to the y-axis, and the z-axis is the vertical axis perpendicular to each of the x-axis and y-axis. While the liquid metal bearing assembly 300 is attached to an X-ray source of an X-ray imaging system, such as the X-ray imaging system 100 described above with reference to FIG. 1, the x-axis is parallel to the direction of gravity. FIG. 3 includes a first detailed view 346 and a second detailed view 348.

[0028] The liquid metal bearing assembly 300 includes a rotating component, sometimes referred to herein as a sleeve 302, and a stationary component, sometimes referred to herein as a shaft 304. The sleeve 302 and the shaft 304 may be coupled such that the sleeve 302 is rotatable relative to the shaft 304. The sleeve 302 and the shaft 304 are each configured with a structure that defines a liquid metal flow path when the liquid metal bearing assembly 300 is assembled (e.g., the shaft 304 is surrounded by the sleeve 302), as shown in FIG. 3. The liquid metal flow path may include a fill port 310, a liquid metal reservoir 312 (e.g., a lubricant reservoir), a flow path (channel) 314, and a gap 316. The fill port 310 is machined as part of or formed (e.g., molded) with the sleeve 302 and is located radially away from the bearing centerline. For example, the bearing centerline may be a rotational centerline 350 similar to or the same as the rotational axis 250 of FIG. 2. The fill port may be located at a first radial distance 322 away from the central axis of rotation 350 (e.g., offset from the central axis of rotation 350 in a radial direction of the central axis of rotation 350). In some examples, a plug (not shown) may be attached to the fill port following introduction of liquid metal into the liquid metal reservoir 312 during assembly of the liquid metal bearing assembly 300. In some embodiments, the liquid metal bearing assembly 300 may be configured to have more than one fill port. For example, the liquid metal bearing assembly 300 may include a fill port 310 on a first radial side of the sleeve 302 and may further include a second fill port (not shown) directly opposite the fill port 310 with respect to the central axis of rotation 350 (e.g., the fill port 310 may be located on the opposite side of the central axis of rotation 350 from the second fill port). As another example, the second fill port may be located at a different axial location than the first fill port or may be located parallel to the bearing axis at a different radial distance from the central axis of rotation 350.In some embodiments, the fill port 310 may have a wetting or anti-wetting coating.

[0029] The liquid metal reservoir 312 can extend annularly around the shaft 304 as a second radial distance 324 between the shaft 304 and the sleeve 302. The liquid metal reservoir 312 can be fluidly coupled to the fill port 310 and the flow passage 314. The liquid metal reservoir 312 and the gap 316 can each hold an approximately equal volume of liquid metal. As an example, the liquid metal reservoir 312 and the gap 316 can each contain an equal volume of liquid gallium. As another example, the liquid metal reservoir 312 and the gap 316 can hold more liquid gallium than the volume that fills the journal gap. As one non-limiting example, the liquid metal can be about 5 grams. The fill port 310 coupled to the liquid metal reservoir 312 can increase the usable volume of the liquid metal reservoir 312. For example, the fill port 310 can increase the liquid metal capacity. Increasing the amount of liquid metal that can be held by liquid metal reservoir 312 may increase the long-term resistance of the bearing to undesirable liquid metal flow, as well as increase desirable bearing performance, e.g., maintenance of a continuous bearing surface, as described further herein.

[0030] The liquid metal flow path, including the liquid metal reservoir 312, the flow passage 314, and the gap 316, may have an annular configuration between the sleeve 302 and the shaft 304. The sloping diameter (e.g., tapering) of the shaft 304 and the sleeve 302 provides a narrowing of the width of the liquid flow path (e.g., between the shaft 304 and the sleeve 302) from the liquid metal reservoir 312 to the gap 316. Stated differently, in the flow passage 314, the diameter of the shaft 304 increases relative to the diameter of the shaft 304 at the liquid metal reservoir 312, and the diameter of the interior of the sleeve 302 decreases relative to the diameter of the interior of the sleeve 302 at the liquid metal reservoir 312, thus reducing the overall width of the liquid metal flow path between the shaft 304 and the sleeve 302 in a direction from the second end 308 to the first end 306 of the shaft.

[0031] During assembly of the liquid metal bearing assembly 300, liquid metal is injected or inserted into the liquid metal reservoir 312 via the fill port 310. The liquid metal is funneled into the gap 316 by the passage 314. The width of the gap 316 may be smaller than the width of a bead of liquid metal, and therefore the liquid metal may not passively flow into the gap 316. The liquid metal wets the bearing surfaces by drawing the liquid metal from the passage 314 into the gap 316 by capillary forces. In this manner, the liquid metal can coat the surfaces of the bearings (e.g., liquid metal journal bearings and / or liquid metal thrust bearings) of the liquid metal bearing assembly 300 to form bearing surfaces having a continuous layer of liquid metal extending between the sleeve 302 and the shaft 304. This can provide smooth, uninterrupted rotation of the sleeve 302 relative to the shaft 304, such as during operation of the x-ray tube to generate an x-ray beam, as described with respect to FIGS. 1 and 2. The liquid metal bearing assembly 300 may further include a seal at a lower region of the first end 306 of the liquid metal bearing assembly 300 designed to reduce the amount of undesired liquid metal flow from the bearing. For example, the seal may be a rotary seal, a compression seal, etc. The seal may impede the flow of liquid metal in an axial direction (e.g., along the central axis of rotation 350) away from an anode, such as the anode 210 shown in FIG.

[0032] The sleeve 302 of the liquid metal bearing assembly 300 may be formed from a first body 302a and a second body 302b, with the separation of the first body 302a and the second body 302b being indicated by an interface 302c. During assembly of the liquid metal bearing assembly 300, the shaft 304 is inserted into the first body 302a of the sleeve 302 from a first end 306. The body 304a of the shaft 304 is formed with a flange 304b that extends radially from the body 304a of the shaft 304. The first body 302a of the sleeve 302 is formed with a complementary section 352 in which the flange 304b may be disposed. When the flange 304b is positioned in the complementary section 352 (e.g., as shown in FIG. 3), the second body 302b of the sleeve 302 is coupled to the first body 302a at the first end 306, enclosing the shaft 304 within the sleeve 302. The first body 302a and the second body 302b may be coupled via bolts, welding, other fasteners, etc. As an example, the second body 302b may be a sleeve cap.

[0033] The first body 302a of the sleeve 302 is configured to have an annular cutout in which the shaft 304 is disposed when the liquid metal bearing assembly 300 is assembled. When the shaft 304 is disposed in the annular cutout of the sleeve 302, a liquid metal trap may be formed therebetween, the liquid metal trap extending a length 318 of the first body 302a and including a complementary section in which the flange 304b of the shaft 304 is disposed. The liquid metal trap may have angled walls in a first region 319 of the length 318 such that a first diameter of the first region 319 gradually increases from the second end 308 toward the y-axis. The liquid metal trap may further be configured to have a second diameter of a second region 320 that decreases downwardly in the y-axis from the flow passage 314 to a third region 321 of the length 318, the third region 321 being a complementary section. The third diameter of the third region 321 may be greater than the second diameter of the second region 320. In other examples, the third diameter of the third region 321 may be smaller than the second diameter of the second region 320. The transitions between the first diameter, the second diameter, and the third diameter are discussed further with respect to Figures 4A-4B and 8-11.

[0034] The liquid metal reservoir 312 is in a first region 319 of the trap formed by the sleeve 302 and the shaft 304. The distance between the sleeve 302 and the shaft 304 in the first region 319 is greater than the distance between the sleeve 302 and the shaft 304 in the gap 316 and the flow passage 314. The liquid metal reservoir 312 may have a first volume and the gap 316 may have a second volume, the second volume being equal to or greater than the first volume. The liquid metal reservoir 312 may be fluidly coupled to the gap 316 by the flow passage 314. As described further herein, the flow passage 314 includes a first portion inclined at a first angle, a second portion inclined at a second angle, and a curved transition portion connecting the first portion and the second portion. The curved transition portion is not straight and does not include a straight portion in the example embodiment. The first angle and the second angle are different.

[0035] A portion of the gap 316 may be disposed at a third angle, the third angle being different relative to the first angle and the second angle. A second portion of the flow passage 314 fluidly couples the flow passage 314 to the gap 316. The gap 316 may have a continuous width along the length of the liquid metal journal bearing 326 (e.g., liquid metal journal bearing 222 of FIG. 2) between the sleeve 302 and the shaft 304. In other embodiments, the gap 316 may have different widths along the length of the liquid metal journal bearing 326. In the illustrated example, the liquid metal journal bearing 326 and the liquid metal thrust bearing 328 (e.g., liquid metal thrust bearing 224 of FIG. 2) may have a continuous layer of liquid metal extending therethrough and therebetween. In one embodiment, at the transition between the liquid metal journal bearing 326 and the liquid metal thrust bearing 328, the configuration of the sleeve 302 and the shaft 304 can form a wetted reservoir 330 that couples the gap 316 to a liquid metal interface 340 of the liquid metal thrust bearing 328. In one embodiment, the liquid metal interface 340 can be a fluid surrounding the liquid metal thrust bearing 328 that extends along a first side 332, a second side 334, and a third side 336 of the flange 304b of the liquid metal thrust bearing 328. The third side 336 of the flange 304b can be configured with a pinning feature 338. For example, a first angle of the flange 304b and a second angle of the shaft 304 at the complementary section 352 can meet to form an acute angle extending annularly therebetween. In this manner, the pinning feature 338 provides fluid pinning and, together with capillary forces, can prevent liquid metal from flowing into the gas reservoir formed by the second body 302b of the sleeve 302 and the shaft 304, here the expansion chamber 342. In this manner, the liquid metal reservoir 312 is fluidly isolated from the expansion chamber 342 by the pinning feature 338. Further details regarding the liquid metal reservoir 312, the flow passage 314, and the gap 316 are described with respect to Figures 4A-4B. Further details regarding the pinning feature 338 and the expansion chamber 342 are described with respect to Figure 8.

[0036] A detailed view 400 of a portion of the liquid metal bearing assembly 300 is depicted in FIG. 4A. The detailed view 400 is similar to the first detailed view 346, including additional details of the liquid metal reservoir 312, the flow passage 314, and the gap 316. In one embodiment, the sleeve 302 and the shaft 304 include a structure having a shape designed to allow liquid metal to flow into the gap 316 during field assembly of the liquid metal bearing assembly 300. This shape may result in reduced gas formation at the interface between the sleeve 302 and the shaft 304 (e.g., interface 226 in FIG. 2), where the liquid metal acts as a lubricant and provides structural support. This shape may also result in a more uniform distribution of liquid metal throughout the bearing assembly. Additionally, this shape allows a sufficient amount of liquid metal to flow into the bearing journal during assembly, reducing underfilling and voids in the journal. The reservoir is sized to completely fill the capillary gap of the bearing without spilling out of the fill port or rotary seal.

[0037] In one embodiment, the liquid metal reservoir 312 is flared in a direction from the second end 308 toward the first end 306. The liquid metal reservoir 312 includes a first portion 312a, which may be narrower than the second portion 312b, and a third portion 312c, which may be wider than the second portion 312b. The second portion 312b may be a portion of the cavity facing the fill port 310, with the first portion 312a above the second portion and the third portion 312c below the second portion 312b. The flared portion of the liquid metal reservoir 312 is formed by the angle of the first body 302a of the sleeve 302. In the first portion 312a, the inner portion 402 and the outer portion 404 of the first body 302a meet at an angle 406, which in this embodiment is about 45 degrees. Also, at the first portion 312a, the interior portion 402 of the sleeve 302 narrows in a direction from the second end 308 to the first end 306. From the angle 406, the liquid metal reservoir 312 increases in radial width from the first portion 312a to the second portion 312b. At the transition between the second portion 312b and the third portion 312c, the liquid metal reservoir 312 increases to a first radial width 408. In one example, the first radial width 408 can hold liquid metal beads (described further herein) having a diameter larger than the diameter of the flow passage 314 in close proximity to the flow passage 314 to promote capillary flow during field assembly.

[0038] The flow passage 314 fluidly couples the liquid metal reservoir 312 to a gap 316 between the sleeve 302 and the shaft 304. In one example, the flow passage 314 tapers in a direction from the second end 308 toward the first end 306. The tapering is formed by a widening of the shaft 304. For example, the shaft 304 can have a second radial width 410 in the region of the liquid metal reservoir 312. The shaft 304 widens in the region of the flow passage 314 to a third radial width 412 in the region of the gap 316. The widening of the shaft 304 from the second radial width 410 to the third radial width 412 includes a first angle, a second angle, a curved transition between the first angle and the second angle, and a third angle. The angles of the shaft 304 are described in FIG. 4B.

[0039] The angled surface of the shaft 304 relative to the sleeve 302 affects the shape of the channel 314. Angled surfaces are described below in FIG. 4B. In one embodiment, the flow passage 314 includes a first portion 314a that is angled at a first angle, a second portion 314c that is angled at a second angle different from the first angle, and a curved transition 314b between the first portion 314a and the second portion 314c. The gap 316 may be angled at a third angle. In one embodiment, the angled surface of the shaft 304 shapes the flow passage 314 such that a liquid metal bead is held above the gap 316 during field assembly. When the liquid metal bead is heated during use, the tapered shape of the flow passage 314 and the gap 316 further increases capillary flow during assembly. For example, the first portion 314a is sized such that the liquid metal contacts the second portion 314c and enables capillary flow. Thus, the liquid metal entering the gap 316 (e.g., journal) can be controlled with the specific wetting characteristics of the shaft chamfer (e.g., transitional edge between two faces of an object).

[0040] A detailed view 450 of a portion of the liquid metal bearing assembly 300 is depicted in FIG. 4B. The detailed view 450 includes additional details of the shaft 304. In one embodiment, the shaft 304 includes an angled surface designed to direct liquid metal into the gap 316 during field assembly of the liquid metal bearing assembly 300. This shape may result in reduced gas formation in the bearing journal, e.g., gap 316, where the liquid metal acts as a lubricant and provides structural support. The shape may also result in a more uniform distribution of liquid metal throughout the assembly. The shape of the structure also facilitates self-alignment of the shaft and sleeve during field assembly, improving manufacturing efficiency.

[0041] The shaft 304 includes an upper section 452. The upper section 452 of the shaft 304 may be adjacent to the liquid metal reservoir 312 (e.g., FIG. 3). A step 454 may be located below the upper section 452. In one example, the step 454 may be a grinding step. Below the step 454, a gradual transition 464 is formed in the shaft 304. The gradual transition 464 includes a first portion 456, a curved transition 458, a second portion 460, and a third portion 462. In one example, the gradual transition 464 may be adjacent to the channel 314 and a transition between the channel 314 and the gap 316 (e.g., FIG. 3).

[0042] In one example, the first section 456 may be inclined at a first angle 456a ranging from a lower boundary of 45° to an upper boundary of 60°. The first section 456 may have a first axial length 456b ranging from a lower boundary of 0.5 mm to an upper boundary of 3 mm, where the axial length is the length in the direction of the axis of rotation (e.g., parallel to the axis of rotation). The first section 456 may have a first radial change 456c ranging from a lower boundary of 1 mm to an upper boundary of 2 mm. In one example, the curved transition 458 may range in length from 4 mm to 9 mm. In one example, the second section 460 may be inclined at a second angle 460a ranging from a lower boundary of 0.5° to an upper boundary of 15°. The second section 460 may have a second axial length 460b ranging from a lower boundary of 1.5 mm to an upper boundary of 7 mm. The second portion 460 may have a second radial change 460c ranging from 0.5 mm to 1 mm. In one example, the third portion 462 may be inclined at a third angle 462a ranging from a lower boundary of 0 degrees to an upper boundary of 2.5 degrees. The third portion 462 may be the length of the journal of the assembly. In one example, the radius at the first radial change 456c is less than the radius at the second radial change 460c, the difference being equal to the length of the second radial change 460c.

[0043] In one embodiment, the first angle 456a is greater than the second angle 460a and acts as a funnel to move liquid metal from the liquid metal reservoir 312 to the passage 314 and gap 316 (e.g., a bearing journal). The magnitude of the first angle 456a allows the bead of liquid metal to better fit into the passage 314, thereby decreasing the distance between the passage 314 and gap 316 for increased capillary flow. The second angle 460a and the corresponding shape of the sleeve 302 allow for self-alignment during assembly. Such shaft and sleeve shapes are described in more detail in FIG.

[0044] Figure 5 shows a detailed view 550 of another embodiment of a shaft 500 that may be implemented in a liquid metal bearing assembly, such as the liquid metal bearing assembly 300 of Figure 3. The shaft 500 is relatively similar in form and function to the shaft 304 shown in Figures 3, 4A, and 4B. In one example, the dimensions of the shaft 500, as well as additional shaft embodiments illustrated below, may be within the ranges of dimensions discussed with respect to Figures 3, 4A-4B.

[0045] For example, shaft 500 includes a gradual transition 502 including a first portion 504 inclined at a first angle 504a, a second portion 508 inclined at a second angle 508a, a curved transition 506 between first portion 504 and second portion 508, and a third portion 510 inclined at a third angle 510a. The first angle 504a, second angle 508a, and third angle 510a of the shaft at the gap (e.g., gap 316 of FIG. 3) may be different in the embodiment of shaft 500 as compared to the embodiment of shaft 304 of FIGS. 3-4B. In one example, first angle 504a may be greater than first angle 456a illustrated with respect to FIG. 4B. In one example, second angle 508a may be greater than second angle 460a illustrated with respect to FIG. 4B.

[0046] The first portion 504 can have a first axial length 511. The curved transition portion 506 and the first portion 504 may together have a second axial length 512. The first portion 504, the curved transition portion 506, and the second portion 508 may together have a third axial length 514. The third portion 510 may have a fourth axial length 516. The first portion 504, the curved transition portion 506, the second portion 508, and the third portion 510 may together have a fifth axial length 518. In an embodiment, the first axial length 511 of the shaft 500 may be similar to the range of lengths discussed with respect to the first axial length 456b of the shaft 304 of FIG. 4B. In an embodiment, the first axial length 511 may be shorter than the first axial length 456b of the shaft 304. In another embodiment, the first axial length 511 may be greater than the first axial length 456b. Similarly, the difference between the second axial length 512 and the third axial length 514 may be similar to the range of lengths discussed for the second axial length 460b of the shaft 304 in FIG. 4B.

[0047] Figure 6 illustrates yet another embodiment of a shaft 600 that may be implemented in a liquid metal bearing assembly, such as the liquid metal bearing assembly 300 of Figure 3. The shaft 600 is relatively similar in form and function to the shaft 304 shown in Figures 3, 4A, and 4B, and the shaft 500 shown in Figure 5. A rotational axis 602 is provided in Figure 6 for reference. The rotational axis 602 may be the same as or similar to the rotational axis 350 of Figures 3 and 4A.

[0048] FIG. 6 includes a detailed view 650 of a shaft 600 including a gradual transition 620. The gradual transition 620 includes a first portion 606 inclined at a first angle 606a, a second portion 610 inclined at a second angle 610a, and a third portion 612. A curved transition 608 may be disposed between the first portion 606 and the second portion 610. In other examples, the angled sections, e.g., the first portion 606 and the second portion 610, may transition directly into one another without a curved transition. In some examples, the shaft 600 may include a tool transition region 604. The first angle 606a, the second angle 610a, and the third angle 612a of the shaft at the gap (e.g., gap 316 of FIG. 3) may be different in the embodiment of the shaft 600 as compared to the embodiment of the shaft illustrated with respect to FIGS. 3-4B and 5. For example, first angle 606a may be less than first angle 504a and second angle 610a may be less than second angle 508a, as described with respect to FIGURE 5. In one example, gradual transition 620 may have a length 614. In one example, length 614 may be less than third axial length 514, as described with reference to FIGURE 5.

[0049] FIG. 7 shows a further embodiment of a shaft 700 that may be implemented in a liquid metal bearing assembly (e.g., liquid metal bearing assembly 300 of FIG. 3) along with a detailed view of the angle used to form a flow passage connecting the liquid metal reservoir to the gap.

[0050] The shaft 700 includes a first portion 702, a second portion 706, a curved transition 704 between the first portion 702 and the second portion 706, and a third portion 714. The shaft 700 includes a first angle 702a and a second angle 706a. The first portion 702 includes a first axial length 708. The second portion 706 includes a second axial length 712. The second portion 706 and the curved transition 704 have a combined axial length 710. The first angle 702a and the second angle 706a of the shaft 700 may be different than the first and second angles of the shafts 304, 500, and 600 illustrated with respect to FIGS. 3-4B, 5, and 6, respectively. For example, the first angle 702a may be greater than the first angle 504a described with respect to FIG. 5. As another example, the second angle 706a may be greater than the second angle 610a described with respect to Figure 6. In one embodiment, the shaft 700 includes a cutaway 716.

[0051] 8 shows a detail view 800 of a portion of the liquid metal bearing assembly 300. The detail view 800 may be similar to the second detail view 348, including additional details of the wetted reservoir 330, the pinning feature 338, and the expansion chamber 342. In particular, the detail view 800 shows features of the liquid metal bearing assembly that may reduce undesirable liquid metal flow from the assembly.

[0052] In one example, the third side 336 of the flange 304b may be in coplanar contact along the surface 804 of the second body 302b. Flow of liquid metal across a liquid metal interface 340 between the third side 336 and the surface 804 may be prevented or reduced by a sharp angle 802, which acts as a discontinuity that changes the capillary force after the discontinuity. A first angled cutout 806 on the third side 336 of the flange 304b and a second angled cutout 808 on the surface 804 of the second body 302b meet and extend annularly to form the sharp angle 802. The sharp angle 802 formed by the line on line transition between the first angled cutaway 806 and second angled cutaway 808 may hold a liquid metal at the intersection of the two sides and may reduce incidence of liquid metal entering lower rotating seals, which may lead to undesired flow due to gas pressure and full wetting of the bearing journal. In one embodiment, the first angled cutaway 806 and the second angled cutaway 808 may be approximately symmetrical and form a sharp point. In another embodiment, two asymmetric cutaways may form a sharp point that acts as a pinning feature.In one example, the first angled notch 806 and the second angled notch 808 meet approximately at a right angle at an acute angle 802. The pinning feature 338 may thus provide fluid pinning and, along with capillary forces, prevent liquid metal from flowing into an expansion chamber 342. In one example, the pinning feature 338 fluidly separates the expansion chamber 342 from the wetted reservoir. As a further example, the pinning feature may be achieved by forming an undercut in a surface. An example of an undercut surface forming a pinning feature is shown in FIG. 18.

[0053] The expansion chamber 342 may be formed by the second body 302b of the sleeve 302 and the shaft 304. The expansion chamber 342 may be defined by an inner surface of the liquid metal bearing assembly 300 forming a cavity having an annular shape. For example, the first surface 810 of the second body 302b may form an outer boundary of the expansion chamber 342. The second surface 812 and the fourth surface 830 of the shaft 304 may form an inner boundary of the expansion chamber 342. The third surface 816 of the flange 304b may be continuous with the first angled notch 806 and may form an upper boundary of the expansion chamber 342. The notch 814 may form the first surface 810 toward the first end 306 of the liquid metal bearing assembly 300 and may form a lower boundary of the expansion chamber 342. The expansion chamber 342, which is desirably free of liquid metal, may act as a gas reservoir to retain liquid metal off-gases.

[0054] A wetting reservoir 330 may fluidly couple the gap 316 and a liquid metal interface 340 surrounding the flange 304b. The wetting reservoir 330 may be formed by the first body 302a of the sleeve 302 and the shaft 304. The wetting reservoir 330 may be defined by an interior surface of the liquid metal bearing assembly 300 forming a cavity having an annular shape. For example, the fourth surface 818 of the first body 302a may form an outer boundary of the wetting reservoir 330. The fifth surface 820 of the shaft 304 may form an interior boundary of the wetting reservoir 330. The fifth surface 820 may be shaped to avoid a sharp transition, for example, such that a floor 822 of the wetting reservoir 330 is lower relative to the first side 332 of the flange 304b, e.g., along the y-axis, and gradually slopes toward the liquid metal interface 340. The shape of the wetting reservoir 330 provides a smooth transition that promotes complete wetting of a liquid metal thrust bearing (e.g., liquid metal thrust bearing 224 of FIG. 2). The shape of the wetted reservoir 330 in combination with the pinning features 338 retains liquid metal in the gap 316 and liquid metal interface 340, allowing for a sufficient amount of liquid metal to be introduced during field assembly while minimizing under-filling and voids in the flow path.

[0055] Figures 9A and 9B are perspective views of a sleeve that may be implemented in a liquid metal bearing assembly, such as the liquid metal bearing assembly 300 of Figure 3. In one example, Figure 9A shows a first perspective view 900 of a sleeve (e.g., sleeve 302) that may be positioned along a second end (e.g., second end 308) of the bearing assembly. Figure 9B shows a second perspective view 950 of a sleeve that may be positioned along a first end (e.g., first end 306) of the bearing assembly.

[0056] Turning first to FIG. 9A , a first perspective view 900 of a first side 902 of a sleeve illustrates an example of a first surface 906 and a second surface 908. The first surface 906 may be joined to the second surface 908 by a step 910. The step 910 may include a slanted (e.g., curved or angled) edge 904. In some examples, the step 910 may be angled (e.g., between 0.5° and 15°) relative to the axis of rotation (e.g., axis of rotation 250 of FIG. 2 ). The angling may reduce the occurrence of deformation of the component in some embodiments.

[0057] 9B illustrates a second perspective view 950 of an example sleeve second body 952 similar to second body 302b of sleeve 302. Second body 952 includes a first surface 954 and a second surface 956 joined by a first step 962. In one embodiment, first step 962 may be disposed approximately perpendicular to first surface 954 and second surface 956. Second body 952 includes a third surface 958 joined to second surface 956 by a second step 960. In one embodiment, second step 960 may be disposed approximately perpendicular to second surface 956 and third surface 958. Second step 960 may include a rounded edge 968.

[0058] The first surface 954 may include a plurality of through holes 966 defined by an inner cylindrical surface 964, an opening 970 on the first surface 954, and an opening on the opposing surface (e.g., opening 826 on opposing surface 824 in FIG. 8). In one example, fasteners (e.g., bolts 828 in FIG. 8) may be inserted through the through holes 966 to secure the second body 952 to the first body of the sleeve (e.g., first body 302a) during field assembly.

[0059] Figure 10 illustrates another embodiment of a sleeve 1000 that may be implemented in a liquid metal bearing assembly, such as the liquid metal bearing assembly 300 of Figure 3. The sleeve 1000 has a relatively similar form and function to the sleeve 302 shown in Figures 3, 9A and 9B.

[0060] In one example, the interior surface of the sleeve 1000 may be variously machined to have different surface finishes. For example, a first region of the sleeve that is radially surrounded by the inner surface of the shaft may have a first surface finish. A second region of the sleeve that is not radially surrounded by the inner surface of the shaft may have a second surface finish that is different from the first surface finish. As an example, the first surface 1002 of the sleeve 1000 may include sections that are turned and sections that are ground. As an example, the sleeve 1000 may have a first region 1004 that is generally cylindrically formed for the first length 1006. As another example, the second region 1008 of the first surface 1002 may be ground for the second length 1010 and the third region 1012 may be turned for the third length 1014. The sleeve 1000 along the second length 1010 may be formed in an uncontrolled cylindrical shape. The ground interface 1016 between the second length 1010 and the third length 1014 may create a step or discontinuity 1018 .

[0061] The first surface 1002 of the sleeve 1000 may be formed to include a first angle 1024 and a second angle 1022. In one example, the first angle 1024 is in the range of 30° to 60° and the second angle 1022 is in the range of 0.5° to 15°. In one example, the shape of the sleeve 1000 can reduce the incidence of liquid metal being retained in a liquid metal reservoir (e.g., liquid metal reservoir 312 of FIG. 3 ) during field assembly, such as during the wetting and coating steps of manufacturing.

[0062] 11A, 11B, and 11C respectively show a first embodiment 1110, a second embodiment 1140, and a third embodiment 1170 of a liquid metal bearing assembly 1100. The liquid metal bearing assembly 1100 embodiments are relatively similar in function to the liquid metal bearing assembly 300 shown in Figures 3, 4A, etc. The first embodiment 1110, the second embodiment 1140, and the third embodiment 1170 show modifications of the liquid metal bearing assembly 1100 that may increase the capillary flow of liquid metal into the bearing journal and facilitate self-alignment of shaft insertion during field assembly.

[0063] The liquid metal bearing assembly 1100 includes a shaft 1102, a sleeve 1104, a fill reservoir 1106, and a bearing gap 1108. The fill reservoir 1106 may be comprised of a void formed by the interior surfaces of the shaft 1102 and the sleeve 1104. For example, the surfaces may include a first surface 1102a of the shaft 1102 and a second surface 1104a of the sleeve 1104.

[0064] 11A shows a first embodiment 1110 that includes a first modification 1112. The first modification 1112 can be a breakaway from the shaft 1102 that enlarges the fill reservoir 1106.

[0065] 11B illustrates a second embodiment 1140 including a first modification 1112 and a second modification 1142. The second modification 1142 may be separate from the second surface 1104a (see, e.g., FIG. 11A) of the sleeve 1104. The second modification 1142 and the first modification 1112 enlarge the fill reservoir 1106 and increase the angle 1144 of the bearing clearance 1108.

[0066] 11C illustrates a third embodiment 1170 including a third modification 1172, a fourth modification 1174, a fifth modification 1176, and a sixth modification 1178. The third modification 1172 may be a cut from the first modification 1112 of the shaft 1102 (see, e.g., FIG. 11A). The fourth modification 1174 and the fifth modification 1176 may be cut from the first surface 1102a of the shaft 1102. The sixth modification 1178 may be cut from the second modification 1142 (see, e.g., FIG. 11B). The modifications enlarge the fill reservoir 1106 and widen the angle 1180 of the bearing clearance 1108.

[0067] The modifications shown in Figures 11A-11C may have various advantages. For example, by widening the fill reservoir 1106, the modifications allow for sufficient liquid metal filling prior to wetting. As another example, by reducing the chamfer of the fill reservoir 1106, the modifications increase capillary flow into the bearing gap 1108. Additionally, reducing chamfers and other sharp transitions may reduce galling and other wear that may occur on the sliding surfaces between the shaft 1102 and sleeve 1104 during assembly in the field.

[0068] 12 illustrates an assembly series 1200 of the liquid metal bearing assembly 300 during insertion of the shaft 304 into the sleeve 302. For example, a first position 1202, a second position 1204, and a third position 1206 of the shaft 304 and sleeve 302 during field assembly are shown. As an example, the matching angles of the sleeve 302 and shaft 304 are aligned to facilitate assembly. For example, the matching angles allow for automatic alignment of the shaft 304 and sleeve 302 during field assembly, improving manufacturing efficiency.

[0069] A gradual transition 464 of the shaft 304 is shown including sections formed with compound angles, such as a first portion 456, a second portion 460, and a third portion 462, and a curved transition 458. The second portion includes a second angle 460a. The first region 1208 of the first body 302a of the sleeve 302 may be formed with a sleeve angle 1208a that is the same or similar to the second angle 460a. The dashed lines 1210, 1212 are drawn to illustrate the gap 316 between the shaft 304 and the sleeve 302 or the bearing journal axis. The second angle 460a and the sleeve angle 1208a may be truncated from the gap 316.

[0070] During assembly, the shaft 304 is inserted into the sleeve 302 from the first end 306. In the first position 1202 during assembly, the shaft 304 approaches the first region 1208 of the sleeve. In the second position 1204, the shaft 304 passes through the first region 1208 of the sleeve 302. The second angle 460a and the sleeve angle 1208a coincide and are decoupled from the gap 316, allowing the shaft 304 and the sleeve 302 to slide past each other. Once the shaft 304 passes through the first region 1208 of the sleeve 302, the distance between them narrows to the gap 316. In the third position 1206, the shaft 304 is fully inserted into the sleeve 302. As an example, once the shaft 304 is fully inserted to meet the second end 308 of the assembly, the liquid metal reservoir 312, the flow passage 314, and the gap 316 can be formed to receive liquid metal or other bearing lubricant.

[0071] 13 is a flow chart illustrating an example method 1300 for a liquid metal bearing assembly. In one example, the liquid metal bearing assembly may be liquid metal bearing assembly 300. In one example, the method 1300 may be performed by an automated system for assembling the liquid metal bearing assembly.

[0072] As an example, at 1302, the method 1300 may include coupling a shaft to a sleeve of the liquid metal bearing assembly by inserting the shaft into the sleeve at an opening at a first end of the sleeve. As an example, matching one or more angled faces or compound angles of the shaft with an angle of the sleeve may allow for automatic alignment during assembly.

[0073] At 1304, the method 1300 can include coupling a sleeve cap to the first end of the sleeve. As an example, the sleeve cap can be the same as or similar to the second body 302b, and the first end of the sleeve can be the same as or similar to the first body 302a described in FIG. 3 and FIG. 8. As an example, joining the sleeve cap to the first end of the sleeve can form a first reservoir (e.g., liquid metal reservoir) at the first end (e.g., second end 308) of the assembly and a second reservoir (e.g., gas reservoir, expansion chamber 342) at the second end (e.g., first end 306). Additionally, when joined, the flange of the shaft and the complementary sections of the sleeve form a pinching feature with an acute angle formed at the interface therebetween. For example, when joined, the sleeve and shaft can form the liquid metal reservoir 312, the wetting reservoir 330, the pinning feature 338, and the expansion chamber 342.

[0074] At 1306, the method 1300 may include injecting liquid metal into the liquid metal reservoir via a fill port disposed at the second end of the assembly. A liquid metal, such as gallium, may be one example of a lubricant that may be used as a bearing in a liquid metal bearing assembly. The fill port may be similar to fill port 310 illustrated, for example, in FIG. 3. In one example, an amount of liquid metal equal to the volume of the liquid metal reservoir may be injected into the liquid metal reservoir. In some examples, additional injections of liquid metal into the reservoir may be performed such that the total amount of injected metal exceeds the volume of the reservoir.

[0075] At 1308, the method 1300 may include heating the liquid metal bearing assembly to create bearing surfaces in the gap between the sleeve and the shaft, whereby the liquid metal flows into the gap using capillary forces. In other words, the liquid metal is drawn into the gap from a liquid metal reservoir by capillary forces. Capillary forces can draw the liquid metal into the gap without heat. In some examples, the liquid metal bearing may not be heated during assembly. As an example, the flow of liquid metal into the expansion chamber may be blocked (e.g., reduced, prevented) by a pinning feature formed between the shaft and the sleeve.

[0076] Figures 14, 15 and 16 show further embodiments of a shaft that may be implemented in a liquid metal bearing assembly (e.g., liquid metal bearing assembly 300 of Figure 3) with angular detail views used to form a flow passage connecting a liquid metal reservoir to a gap. In one example, the dimensions of the further embodiments of the shaft described with respect to Figures 14-16 may be within the ranges of dimensions described with respect to Figures 3, 4A-4B.

[0077] FIG. 14 illustrates a shaft 1400. The shaft 1400 includes a first portion 1402, a second portion 1408, a curved transition 1404 between the first portion 1402 and the second portion 1408, and a third portion 1422. The shaft 1400 includes a first angle 1412, a second angle 1414, and a third angle 1416. The first portion 1402 has a first axial length 1410. The second portion 1408 has a second axial length 1406. The curved transition 1404 has a transition axial length 1420. The shaft 1400 has a third axial length 1418 that includes the first portion 1402, the second portion 1408, the curved transition 1404, and the third portion 1422.

[0078] In some examples, the first angle 1412, the second angle 1414, and the third angle 1416 may be different than the first angle, the second angle, and the third angle of the various embodiments of the shaft illustrated with respect to Figures 3-4B, 5, 6, and 7. For example, the first angle 1412 may be less than the first angle 504a described with respect to Figure 5. The first angle 1412 may be greater than the first angle 606a described with respect to Figure 6. The second angle 1414 may be greater than the second angle 508a described with respect to Figure 5.

[0079] In some examples, the first axial length 1410, the second axial length 1406, the transition axial length 1420, and the third axial length 1418 may differ from the corresponding axial lengths of the various embodiments of the shaft illustrated with respect to Figures 3-4B, 5, 6, and 7. For example, the first axial length 1410 may be longer than the first axial length 511 described with respect to Figure 5. The third axial length 1418 may be shorter than the fifth axial length 518 described with respect to Figure 5. As another example, the first axial length 1410 may be longer than the first axial length 708 described with respect to Figure 7.

[0080] 15 illustrates a shaft 1500. The shaft 1500 includes a first portion 1502, a second portion 1504, a third portion 1508, and a curved transition portion 1506. The shaft 1500 includes a first angle 1510, a second angle 1512, and a third angle 1514. The first portion 1502 has a first axial length 1524. The curved transition portion 1506 and the first portion 1502 have a second axial length 1516. The first portion 1502, the second portion 1504, a portion of the third portion 1508, and the curved transition portion have a third axial length 1520.

[0081] In some examples, the first angle 1510, the second angle 1512, and the third angle 1514 may differ from the corresponding angles of the various embodiments of the shaft illustrated with respect to Figures 3-4B, 5-7, and 14. For example, the first angle 1510 may be greater than the first angle 1412 described with respect to Figure 14. The first angle 1510 may be greater than the first angle 504a described with respect to Figures 5 and 6. The second angle 1512 may be less than the second angle 508a described with respect to Figure 5.

[0082] In some examples, the first axial length 1524, the second axial length 1516, and the third axial length 1520 may differ from the corresponding axial lengths of the various embodiments of the shaft illustrated with respect to Figures 3-4B, 5, 6, and 7. For example, the first axial length 1524 may be shorter than the first axial length 708 described with respect to Figure 7. The third axial length 1520 may be longer than the third axial length 1418 described with respect to Figure 14.

[0083] FIG. 16 illustrates a shaft 1600. The shaft 1600 includes a first portion 1602, a second portion 1604, and a third portion 1608. The shaft 1600 includes a first angle 1610 and a second angle 1612. In some examples, the first angle 1610 and the second angle 1612 may be different than the first angle and the second angle of the various embodiments of the shaft illustrated with respect to FIGS. 3-4B, 5-7, and 14-15. For example, the second angle 1612 may be smaller than the second angle 1414 described with respect to FIG. 14. The shaft 1600 does not include a curved transition between the first angle 1610 and the second angle 1612 (e.g., the curved transition 1404 of FIG. 14). In other examples, the shaft 1600 may include a curved transition between the first angle 1610 and the second angle 1612.

[0084] 17 illustrates one example of a liquid metal bearing assembly 1700. The liquid metal bearing assembly 1700 is a configuration for the disclosed liquid metal bearings in which the components are arranged in an alternative orientation (e.g., as opposed to the orientation of the components in FIG. 3). In the example, a fill port and pinning feature may be in an opposite orientation such that the fill port and angles creating the reservoir and entrance to the gap are on the seal side of the bearing, e.g., a first end 1706, and the pinning feature is on the opposite end of the shaft with the sleeve, e.g., a second end 1708.

[0085] The liquid metal bearing assembly 1700 includes a sleeve 1702 and a shaft 1704. In one example, the sleeve 1702 may be a rotating component and the shaft 1704 may be a stationary component. The sleeve 1702 and the shaft 1704 may be coupled such that the sleeve 1702 is rotatable relative to the shaft 1704. The sleeve 1702 of the liquid metal bearing assembly 1700 may be formed from a first body 1702a and a second body (not shown, e.g., 302b in FIG. 3). The body 1704a of the shaft 1704 is configured with a flange 1704b extending radially from the body 1704a of the shaft 1704. The first body 1702a of the sleeve 1702 is configured with a complementary section 1722 on which the flange 1704b may be disposed.

[0086] Each of the sleeve 1702 and the shaft 1704 is configured to have a structure that forms a liquid metal flow path when the liquid metal bearing assembly 1700 is in an assembled state. The liquid metal flow path may include a fill port 1710, a first reservoir 1712 (e.g., liquid metal reservoir, gallium reservoir), a flow path 1714, and a gap 1716. Liquid metal may be introduced into the first reservoir 1712 via the fill port 1710 during assembly. The flow path 1714 may include an angle to facilitate flow from the first reservoir 1712 to the gap 1716. The fill port 1710, the first reservoir 1712, and the flow path 1714 are disposed at a first end 1706 of the liquid metal bearing assembly 1700.

[0087] The sleeve 1702 includes a pinning feature including a sleeve element 1752 and a shaft element 1750. The sleeve element 1752 and the shaft element 1750 reduce the inflow of gallium into undesirable regions of the liquid metal bearing assembly 1700 by pinning the gallium within the gap 1716. The sleeve element 1752 and the shaft element 1750 are disposed at a second end of the liquid metal bearing assembly 1700.

[0088] During assembly of the liquid metal bearing assembly 1700, the shaft 1704 is inserted into the first body 1702a of the sleeve 1702 from the first end 1706. When the flange 1704b is positioned in the complementary section 1722 (e.g., as shown in FIG. 17), the second body of the sleeve 1702 can be coupled to the first body 1702a at the first end 1706 to enclose the shaft 1704 within the sleeve 1702. The first body 1702a and the second body may be coupled via bolts, welding, other fasteners, etc. As an example, the second body may be a sleeve cap. In this manner, the fill port 1710 and the first reservoir 1712 are located on the seal side of the bearing, and the pinning feature is located on the opposite end of the bearing between the shaft 1704 and the sleeve 1702.

[0089] 18 illustrates an example of a liquid metal bearing assembly 1800. The liquid metal bearing assembly 1800 is a disclosed liquid metal bearing configuration exhibiting additional or alternative pinning features. The liquid metal bearing assembly 1800 may in other aspects be the same as or similar to the example liquid metal bearing assemblies described above with respect to FIGS. 2-17.

[0090] The liquid metal bearing assembly 1800 includes a sleeve 1802 and a shaft 1804. In one example, the sleeve 1802 may be a rotating component and the shaft 1804 may be a stationary component. The sleeve 1802 and the shaft 1804 may be coupled such that the sleeve 1802 is rotatable relative to the shaft 1804. The sleeve 1802 of the liquid metal bearing assembly 1800 may be formed from a first body 1802a and a second body (not shown, e.g., 302b in FIG. 3). The body 1804a of the shaft 1804 is configured with a flange 1804b extending radially from the body 1804a of the shaft 1804. The first body 1802a of the sleeve 1802 is configured with a complementary section 1814 in which the flange 1804b may be disposed.

[0091] A gap 1816 is formed between the sleeve 1802 and the shaft 1804. Liquid metal introduced during assembly may fill the gap 1816. The liquid metal may be prevented from flowing past the gap 1816 by a pinning feature that separates the gap 1816 from a gas reservoir, indicated by arrow 1806. The placement and shape of the pinning feature may help reduce the amount of liquid metal that may undesirably flow to the lower rotating seal and reservoir in the bearing outside the journal surface. In an example, a first pinning feature 1824 and a second pinning feature 1834 are shown in the same bearing assembly. However, it may be understood that a manufactured bearing assembly may include only one of the first pinning feature 1824, the second pinning feature 1834, the pinning feature 338, or other similar configurations.

[0092] The first pinning feature 1824 includes the first sleeve element 1820 and the first shaft element 1822. The first pinning feature 1824 is an example where two asymmetric cutaways may be used to pin the liquid metal in the gap 1816. For example, the first shaft element 1822 may be created with an asymmetric cutaway on the first surface 1826, while the first sleeve element 1820 may not have such a cutaway. In one embodiment, the asymmetric cutaway on the first surface 1826 may form an acute angle (e.g., a 45° angle).

[0093] Alternatively, the pinning feature may be accomplished by forming an undercut in a surface. For example, the second pinning feature 1834 is comprised of a second sleeve element 1830 and a second shaft element 1832. The second sleeve element 1830 may be created by an undercut on the second surface 1836, and the second shaft element 1832 may be created by a matching symmetrical undercut on the third surface 1838. In one example, the undercut on the second surface 1836 may form an acute angle (e.g., a 45° angle), and the undercut on the third surface 1838 may form a similar acute angle in a symmetrical orientation.

[0094] Some embodiments of the disclosed liquid metal bearing assembly may include multiple fill ports, multiple liquid metal reservoirs, and / or multiple pinning features. For example, there may be multiple fill ports located at different axial and radial locations. Similarly, in some embodiments, the assembly may include one or more pinning features. In some examples, the disclosed liquid metal bearing assembly may include one or more of each of the fill ports, pinning features, and liquid metal reservoirs. For example, there may be a first liquid metal reservoir, an associated first fill port, and an associated first pinning feature located at a first end of the bearing. At a second end of the bearing at a different axial location, there is a second liquid metal reservoir, an associated second fill port, and an associated second pinning feature. In some examples, the first pinning feature may be a different shape than the second pinning feature, and in other examples, they may be similarly shaped. For example, the first pinning feature may be similar to the pinning feature described with reference to FIG. 8, and the second pinning feature may be similar to the first or second pinning feature described with reference to FIG. 18.

[0095] Thus, the disclosed liquid metal bearing assembly addresses current challenges in manufacturing liquid metal bearings by promoting good capillary wetting and retention of liquid metal. The geometry of the disclosed liquid metal bearing assembly reduces alignment difficulties and allows for self-alignment during the assembly process, thereby improving yield and reducing capacity constraints during manufacturing. By reducing alignment difficulties, the disclosed liquid metal bearing assembly can reduce reliance on lubricants used during assembly, which in some instances can contaminate the liquid metal and interfere with the lubricating ability of the liquid metal. Additionally, the disclosed liquid metal bearing assembly promotes complete wetting with the liquid metal and reduces the amount of liquid metal that can undesirably flow into the bearing outside of the journal surface through strategic application of capillary forces. The technical effect of using a liquid metal reservoir in a liquid metal bearing is to provide a precise amount of liquid metal to the bearing interface while reducing the amount of gas at the bearing interface.

[0096] The present disclosure also provides a support for a liquid metal bearing, the support comprising a flow passage fluidly coupling a liquid metal reservoir to a gap between a sleeve and a shaft, the flow passage having a first portion inclined at a first angle and a second portion inclined at a second angle, the first angle being different from the second angle. In a first embodiment of the system, the first portion has a first length and the second portion has a second length different from the first length. In a second embodiment of the system, optionally including the first embodiment, the liquid metal reservoir has a first volume and the gap has a second volume equal to or greater than the first volume. In a third embodiment of the system, optionally including one or both of the first and second embodiments, the system further comprises a fill port having a first end opening to the liquid metal reservoir and a second end including a plug. A fourth embodiment of the system optionally includes one or more of the first through third embodiments, wherein a first region of the sleeve radially surrounded by the inner surface of the shaft has a first surface finish, and a second region of the sleeve not radially surrounded by the inner surface of the shaft has a second surface finish different from the first surface finish. A fifth embodiment of the system optionally includes one or more of the first through fourth embodiments, wherein the system further includes a pinching feature disposed at an interface of a flange of the shaft and a complementary portion of the sleeve, the pinching feature separating the gap from an expansion chamber formed between the sleeve and the shaft. A sixth embodiment of the system optionally includes one or more of the first through fifth embodiments, wherein the system further includes a curved transition disposed between the first portion and the second portion. A seventh embodiment of the system optionally includes one or more of the first through sixth embodiments, wherein the gap has a third angle different from the first angle and the second angle. In an eighth embodiment of the system, optionally including one or more or each of the first to seventh embodiments, the system further includes a wetting reservoir fluidly coupled to the liquid metal reservoir by a gap, and the wetting reservoir is fluidly separated from the expansion chamber by the pinning feature.

[0097] The present disclosure also provides a support for an X-ray imaging system comprising a collector assembly, a cathode assembly, and an anode assembly including an anode supported for rotation by a bearing assembly formed of a rotating member having a stationary member disposed therein, the bearing assembly further comprising a flow passage fluidly coupling a liquid metal reservoir to a gap between the rotating member and the stationary member, and a feature extending annularly from the stationary member separating the gap from the gas reservoir. In a first embodiment of the system, the stationary member is a shaft. In a second embodiment of the system, optionally including the first embodiment, the flow passage includes a first portion inclined at a first angle, a second portion inclined at a second angle, the first angle being different from the second angle, and a curved transition between the first portion and the second portion.

[0098] The present disclosure also provides a method of assembling a bearing, comprising inserting a shaft into a sleeve, forming a first reservoir at a first end of the bearing between the shaft and the sleeve, and a second reservoir at a second end of the bearing between the shaft and the sleeve, forming a gap between the first reservoir and the second reservoir, the gap being separated from the second reservoir by a pinning feature, inserting a lubricant into the first reservoir through a fill port, and using capillary forces to cause the lubricant to flow from the first reservoir into the gap. A first embodiment of the method includes heating the shaft and sleeve to cause the lubricant to flow from the first reservoir into the gap. A second embodiment of the method optionally includes the first embodiment, and the lubricant is a first volume of gallium, and the first volume of gallium is drawn from the first reservoir into the gap by capillary forces. In a third embodiment of the method, optionally including one or both of the first and second embodiments, the first volume of gallium is equal to or less than the volume of the first reservoir. In a fourth embodiment of the method, optionally including one or more of the first through third embodiments, the method further includes grinding a surface of the shaft and an inner surface of the sleeve such that the first reservoir and the gap have a first surface finish and the second reservoir has a second surface finish different from the first surface finish. In a fifth embodiment of the method, optionally including one or more of the first through fourth embodiments, the method further includes wetting or anti-wetting an inner surface of the shaft and the sleeve. In a sixth embodiment of the method, optionally including one or more of the first through fifth embodiments, the method further includes inserting the shaft into the sleeve includes sliding the shaft into the sleeve through an opening at a first end of the sleeve, the shaft and the sleeve forming a matching angle for ease of assembly. A seventh embodiment of the method, optionally including one or more or each of the first to sixth embodiments, wherein the fill port and the first reservoir are located on a seal side of the bearing and the pinning feature is located on an opposing end of the bearing between the shaft and the sleeve.

[0099] When introducing elements of various embodiments of the present disclosure, the articles "a," "an," and "the" are intended to mean that there are one or more of the element. The terms "first," "second," and the like do not denote an order, quantity, or importance, but rather are used to distinguish one element from another. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. As terms such as "connected," "coupled," and the like are used herein, one object (e.g., a material, element, structure, member, etc.) can be connected to or coupled to another object, regardless of whether the one object is directly connected or coupled to the other object, or whether there are one or more intervening objects between the one object and the other object. In addition, it should be understood that references to "one embodiment" or "an embodiment" in the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the referenced features. As used herein, "approximately" and "substantially" refer to values ​​within plus or minus 5%, unless otherwise specified.

[0100] In addition to the modifications shown above, numerous other variations and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of this specification, and the appended claims are intended to cover such modifications and arrangements. Thus, while the above description has been given with specificity and detail in connection with what are presently considered to be the most practical and preferred embodiments, it will be apparent to those skilled in the art that numerous modifications, including but not limited to form, function, method of operation and method of use, can be made without departing from the principles and concepts described herein. Also, the examples and embodiments, as used herein, are intended to be illustrative in all respects and should not be construed as limiting in any manner. [Explanation of symbols]

[0101] 100: X-ray imaging system 102: Subject 104: X-ray source 106: X-ray radiation beam 108: Detector array 110: X-ray controller 112: Computing device 114: Processor 116: Operator console 118: Storage device 120: Display 200: X-ray tube 202: Housing 204: Low pressure enclosure 205: Liquid metal bearing assembly 206: Stationary parts 208: Rotating parts 210: Anode 212: Cathode 214: X-ray beam 216: X-ray window 218: Rotor 220: Stator 222: Liquid metal journal bearing 224: Liquid metal thrust bearing 226: Interface 250: Rotating shaft 252: Radial shaft 300: Liquid metal bearing assembly 302: Sleeve 302a: First body 302b: Second body 302c: interface 304: shaft 304a: body 304b: flange 306: first end 308: second end 310: fill port 312: liquid metal reservoir 312a: first portion 312b: second portion 314: flow passage 314a: first portion 314b: curvilinear transition 314c: second portion 316: gap 318: length 319: first region 320: second region 321: third region 322: first radial distance 324: second radial distance 326: liquid metal journal bearing 328: liquid metal thrust bearing 330: wetted reservoir 332: first side 334: second side 336: third side 38: pinning feature 340: liquid metal interface 342: Expansion chamber 346: First detailed view 348: Second detailed view 350: Rotation axis 352: Complementary section 399: Shaft 400, 450, 550, 800: Detailed view 402: Inner portion 404: Outer portion 406: Angle 408: First radial width 410: Second radial width 12: Third radial width 452: Upper section 454: Step 456: First portion 456a: First angle 456b: First axial length 456c: First radial change 458: Curved transition 460: Second portion 460a: Second angle 460b: Second axial length 460c: Second radial change 462: Third portion 462a: Third angle 464: Gradual transition500, 600, 700, 1400, 1500, 1600: shaft 502: gradual transition 504: inclined first section 504a: first angle 506: curved transition 508: second section 508a: second angle 510: third section 510a: third angle 511: first axial length 512: second axial length 514: third axial length 516: fourth axial length 602: rotation axis 604: tool transition region 606: first section 606a: first angle 608: curved transition 610: second section 612: third section 612a: third angle 14: length 620: gradual transition 702: first section 702a: first angle 704: curved transition 706: second portion 706a: second angle 708: first axial length 710: combined axial length 712: second axial length 714: third portion 716: notch 802: acute angle 804: face 806: first angled notch 808: second angled notch 810: first surface 812: second surface 814: notch 816: third surface 818: fourth surface 820: fifth surface 822: floor 824: opposing surface 826: opening 828: bolt 830: fourth surface 900: first perspective 902: first side 904: edge 906: first surface 908: second surface 910: step 950: second perspective view 952: second body 954: first surface 956: second surface 958: third surface 960: second step 962: first step 964: inner cylindrical surface 966: through hole 968: rounded edge 970: opening 1000: sleeve 1002: first surface 1004: first region 1006: first length 1008: second region 1010: second length 1012: third region 1014: third length 1016: grinding interface 1018: step or discontinuity 1022: second angle 1024: first angle 1100, 1110, 1140, 1170, 1700, 1800: liquid metal bearing assembly 1102: shaft; 1102a: first surface; 1104: sleeve; 1104a: second surface; 1106: fill reservoir; 1108: bearing gap; 1112: first modification; 1142: second modification; 144, 1180: angle; 1172: third modification.1174: fourth modification 1176: fifth modification 1178: sixth modification 1200: assembly series 1202: first position 1204: second position 1206: third position 1208: first region 1208a: sleeve angle 1210, 1212: dashed lines 1402: first section 1404: curved transition section 1406: second axial length 1408: second section 1410: first axial length 1412: first angle 1414: second angle 1416: third angle 1418: third axial length 1420: axial length of transition section 1422: third section 1502: first section 1504: second section 1506: curved transition section 1508: third section 1510: first angle 1512: second angle 1514: third angle 1516: second axial length 1520: third axial length 1524: first axial length 1602: first portion 1604: second portion 1608: third portion 1610: first angle 1612: second angle 1702: sleeve 1702a: first body 1704: shaft 1704a: body 1704b: flange 1706: first end 1708: second end 1710: fill port 1712: first reservoir 1714: flow passage 1716: gap 1722: complementary section 1750: shaft element 1752: sleeve element 1802: sleeve 1802a: first body 1804: shaft 1804a: body 1804b: flange 1806: arrow 1814: complementary section 1816: gap 1820: first sleeve element 1822: first shaft element 1824: first pinning feature 1826: first surface 1830: second sleeve element 1832: second shaft element 1834: second pinning feature 1836: second surface 1838: third surface

Claims

1. A liquid metal bearing, a flow passage fluidly connecting the liquid metal reservoir to the gap between the sleeve and the shaft; A liquid metal bearing, wherein the flow passage has a first portion inclined at a first angle and a second portion inclined at a second angle, the first angle being different from the second angle.

2. 2. A liquid metal bearing as claimed in claim 1, wherein said first portion has a first length and said second portion has a second length different from said first length.

3. 2. A liquid metal bearing as claimed in claim 1, wherein said liquid metal reservoir has a first volume and said gap has a second volume equal to or greater than said first volume.

4. 2. A liquid metal bearing as claimed in claim 1, further comprising a fill port having a first end opening into said liquid metal reservoir and a second end carrying a plug.

5. 2. The liquid metal bearing of claim 1, wherein a first region of the sleeve radially surrounded by an inner surface of the shaft has a first surface finish, and a second region of the sleeve not radially surrounded by the inner surface of the shaft has a second surface finish different from the first surface finish.

6. 2. The liquid metal bearing of claim 1, further comprising a pinning feature at an interface between a flange of the shaft and a complementary portion of the sleeve, the pinning feature separating the gap from an expansion chamber formed between the sleeve and the shaft.

7. The liquid metal bearing of claim 1 further comprising a curved transition disposed between said first portion and said second portion.

8. The liquid metal bearing of claim 1 , wherein the gap has a third angle different from the first angle and the second angle.

9. The liquid metal bearing of claim 1 further comprising a wetting reservoir fluidly coupled to said liquid metal reservoir by said gap, said wetting reservoir fluidly separated from an expansion chamber by a pinning feature.

10. 1. An X-ray source comprising: A cathode assembly; an anode assembly comprising an anode, the anode is supported for rotation by a bearing assembly; the bearing assembly being formed by a rotating member with a stationary member disposed within the rotating member; The bearing assembly includes a flow passage fluidly coupling a liquid metal reservoir to a gap between the rotating member and the stationary member, and an annular extending feature from the stationary member separating the gap from a gas reservoir.

11. The x-ray source of claim 10 , wherein the stationary member is a shaft.

12. 11. The x-ray source of claim 10, wherein the flow path comprises a first portion inclined at a first angle, a second portion inclined at a second angle, the first angle being different from the second angle, and a curved transition section between the first portion and the second portion.

13. 1. A method of assembling a bearing, comprising the steps of: inserting the shaft into the sleeve to form a first reservoir at a first end of a bearing between the shaft and the sleeve, a second reservoir at a second end of the bearing between the shaft and the sleeve, and a gap between the first reservoir and the second reservoir, the gap being separated from the second reservoir by a pinning feature; inserting lubricant into the first reservoir via a fill port; utilizing capillary forces to cause the lubricant to flow from the first reservoir into the gap.

14. The method of claim 13 , wherein the flowing step includes heating the shaft and the sleeve to cause the lubricant to flow from the first reservoir to the gap.

15. 14. The method of claim 13, wherein the lubricant is a first volume of gallium, and the first volume of gallium is drawn from the first reservoir into the gap by capillary forces.

16. 16. The method of claim 15, wherein the first volume of the gallium is less than or equal to a volume of the first reservoir.

17. 14. The method of claim 13, further comprising grinding a surface of the shaft and an inner surface of the sleeve such that the first reservoir and the gap have a first surface finish and the second reservoir has a second surface finish different from the first surface finish.

18. The method of claim 13 further comprising wetting or preventing moisture from entering the interior surfaces of the shaft and the sleeve.

19. 14. The method of claim 13, wherein inserting the shaft into the sleeve includes sliding the shaft into the sleeve from an opening in a first end of the sleeve, the shaft and sleeve including matching angles that align to facilitate assembly.

20. 20. The method of claim 19, wherein the fill port and the first reservoir are located on a seal side of the bearing and the pinning feature is located on an opposing end of the bearing between the shaft and the sleeve.

Images