Miniature axial flow pump with press-fit impeller

Abstract

The invention provides a micro axial flow pump with a press-fit impeller. An axial flow pump for delivering a liquid coolant to cool an electronic device includes a conduit, an impeller located in the conduit, a shaft, a rotor, and a motor stator. The conduit defines a flow path from an inlet of the conduit to an outlet of the conduit. The rotor is disposed in the hollow interior of the impeller and includes a magnetic portion, a front bearing housing, and a rear bearing housing. The front and rear bearing housings include bearings that rotatably couple the rotor to the shaft. The motor stator is configured to drive rotation of the rotor about the shaft, wherein the impeller rotates with the rotor about an axis of rotation extending parallel to the flow path. The rotor is coupled to the impeller by a press-fit attachment of the front bearing housing with the impeller.

Description

Background Technology

[0001] Some information processing systems utilize liquid cooling technology to remove heat from the system. In these systems, a liquid coolant circulates in a loop through the system's information processing units (e.g., servers, network devices, etc.), and heat-generating components of the system (e.g., processors) are thermally coupled to the liquid coolant (e.g., via cold plates), causing the liquid coolant to absorb heat from these components. When the now-heated coolant leaves the information processing unit, it transfers heat to a cooling device (e.g., a heat exchanger), which cools the liquid back to the desired operating temperature. The cooled liquid then circulates again through the loop, extracting more heat from the information processing unit. This liquid cooling loop uses one or more pumps to drive the liquid circulation through the loop. Typically, these pumps are housed in a so-called coolant distribution unit (CDU), which provides a centralized pumping unit that allows the liquid to circulate collectively through multiple information processing units (e.g., an entire rack or multiple racks of such units). These pumps are typically very large, with the CDU often occupying the majority of the rack, or in some cases, the entire rack. Attached Figure Description

[0002] Alone or with Figure 1 This disclosure will be understood from the following detailed description. These accompanying drawings are included to provide a further understanding of this disclosure, and are incorporated in and form a part of this specification. The drawings illustrate one or more examples of the teachings and, together with the description, explain certain principles and operations. In the drawings:

[0003] Figure 1 This is a schematic diagram showing a top view of an example pump.

[0004] Figure 2 This is a 3D view of another example pump.

[0005] Figure 3 yes Figure 2 An exploded view of the pump.

[0006] Figure 4 yes Figure 2 An exploded perspective view of the impeller chamber subassembly of the pump, including a perspective sectional view of a portion of the impeller chamber subassembly, wherein the section is along... Figure 2 It is cut off by plane 4-4 in the middle.

[0007] Figure 5 yes Figure 2 An exploded 3D view of the pump's rotor and shaft.

[0008] Figure 6 yes Figure 5A partially exploded 3D view of the rotor and shaft in a partially assembled state.

[0009] Figure 7 yes Figure 5 A three-dimensional view of the rotor and shaft in their assembled state.

[0010] Figure 8 yes Figure 2 Front view of the front bearing housing of the pump rotor.

[0011] Figure 9 yes Figure 8 A front perspective view of the front bearing housing.

[0012] Figure 10 yes Figure 8 Rear-view perspective of the front bearing housing.

[0013] Figure 11 yes Figure 2 Rear perspective view of the rear bearing housing of the pump rotor.

[0014] Figure 12 yes Figure 11 Rear perspective view of the rear bearing housing, in which the rear radial bearing is installed.

[0015] Figure 13 yes Figure 11 Rear perspective view of the rear bearing housing, in which the rear thrust bearing is installed.

[0016] Figure 14 yes Figure 11 Rear perspective view of the rear bearing housing, in which a retainer is installed.

[0017] Figure 15 yes Figure 2 A perspective sectional view of the pump impeller / rotor subassembly in a partially assembled state, wherein the section is along... Figure 2 It is cut off from plane 4-4 as indicated in the middle.

[0018] Figure 16 yes Figure 2 The cross-section of the pump impeller / rotor subassembly in the assembled state, wherein the cross-section is along... Figure 2 It is cut off from plane 4-4 as indicated in the middle.

[0019] Figure 17 yes Figure 2 The cross-section of the pump, where the cross-section is along...

[0020] Figure 18 This is a schematic diagram of an information processing system with a pump. Detailed Implementation

[0021] In some cases, it may be desirable to utilize relatively small pumps in the liquid cooling loop, rather than the large CDU pumps commonly used. One advantage of using smaller pumps in liquid-cooled information processing systems is that smaller pumps can be more efficient than larger pumps in terms of the amount of liquid that can be moved per unit of energy consumption. Smaller pumps can also be installed in locations where large pumps would be inaccessible, opening up opportunities for system designers to arrange their systems in new and potentially more efficient ways that might otherwise be impractical. For example, smaller pumps can allow for the use of a distributed pumping architecture, where each information processing unit is equipped with one or more small pumps located within or near the unit to individually control the localized circulation of fluid through that unit, rather than using a single large, centralized pumping unit to control the common flow of fluid through these units. This distributed approach can improve the efficiency and performance of the liquid cooling loop, potentially reducing power usage and noise, while also delivering more coolant flow (and thus better cooling). Additionally, this can facilitate greater modularity and scalability of the system, as the system's pumping capacity naturally scales with cooling demands, since each new unit added to the system comes with its own pump.

[0022] While using smaller pumps may theoretically be advantageous, realizing these advantages using existing pumping technology can be challenging. Many existing pumps capable of generating the pressure and flow rates required for liquid cooling of information processing devices are simply too large or too bulky to fit well into the densely packed environments of such devices. Other pumps (such as artificial heart pumps) may be small enough to fit into space-constrained information processing systems, but these pumps often have insufficient pumping characteristics for liquid cooling contexts (e.g., insufficient pressure, insufficient flow, poor efficiency, etc.). In other words, finding a pump that has both a suitable small form factor and the desired pumping characteristics is challenging. Therefore, to meet this unique combination of challenges, specialized pumps have been developed, such as the micro axial flow pump described in U.S. Patent No. 11015608B2, the contents of which are incorporated herein by reference in their entirety. An axial flow pump has an impeller (the part that moves within the liquid to drive the flow) that rotates along an axis coaxial with the direction of liquid flow, unlike a centrifugal pump, which has an impeller that rotates along an axis transverse to the direction of liquid flow. This axial arrangement, along with various other improvements, allows miniature axial flow pumps to have form factors that are both extremely small and easily shaped (e.g., rectangular cross-sections), while still providing the same or better effectiveness and efficiency as larger pumps. For example, some miniature axial flow pumps under development can be similar in size and shape to a deck of cards, while being able to provide flow rates such as 4 GPM at 4 PSI (i.e., with a pressure drop of 4 PSI), 2 GPM at 11.5 PSI, or 1 GPM at 13.9 PSI.

[0023] However, the small size and other structural aspects of such miniature axial flow pumps can present various technical challenges, particularly when it comes to the manufacture and assembly of such pumps. One such challenge involves assembling the pump impeller to the pump rotor to form an impeller / rotor subassembly. The impeller has a hollow interior in which the pump rotor is housed. The rotor includes a set of magnets that are driven to rotate by the magnetic force generated by the pump, and includes bearings that rotatably connect the rotor to a shaft. The rotor needs to be attached to the impeller such that when the rotor is driven to rotate, the impeller is forced to rotate with the rotor, thereby moving liquid through the pump.

[0024] However, it can be difficult to attach the impeller to the rotor in an efficient and reliable manner. One approach considered is to use epoxy resin or other adhesives to bond the outer surface of the rotor to the inner surface of the hollow interior of the impeller. However, the risk of using this method is that the epoxy resin or other agents may leak into the bearings, causing them to glue or impair their performance. Additionally, the epoxy resin may not be evenly distributed around the rotor, which could disrupt the rotor's balance, leading to wobbling, which could reduce pump efficiency, generate more noise, and / or cause premature failure. To mitigate these risks, one could attempt to use only a small, precisely controlled amount of epoxy resin deposited at precisely controlled locations, but this would likely require high-precision epoxy resin dispensing equipment. Such equipment can be very expensive and complex to operate, increasing the cost of the pump and creating a bottleneck in the manufacturing process. Even with such expensive and complex equipment, there is still some variability in the amount and location of the epoxy resin, and therefore the concerns mentioned above may not be completely eliminated. Furthermore, the strength of the bond produced by the adhesive and the compatibility of the adhesive with other materials and with the liquid in the cooling circuit may be uncertain, and therefore may require time-consuming research to find and validate suitable materials.

[0025] Therefore, to address the aforementioned problems (among other things), this disclosure provides a miniature axial flow pump in which the impeller and rotor are configured to be joined together by a press fit, in some cases without the need for any epoxy resin or other adhesives to bond the two parts together. In some examples, the rotor includes a front bearing housing that is axially inserted into the impeller until it finally engages the front engagement portion of the impeller and is press-fitted into a bore in the front engagement portion. The front bearing housing and the front engagement portion of the impeller can be configured to have an interference fit, meaning that the outer diameter of the front bearing housing at its widest point(s) exceeds the inner diameter of the bore in the front engagement portion of the impeller. As a result of this interference fit, when the impeller and rotor are pressed together (e.g., using a hydraulic press), the bearing housing “bites” into the front engagement portion of the impeller, thereby displacing material on the inner surface of the impeller. This press-fit connection mechanically attaches the impeller to the bearing housing by creating a high-friction interface between the bearing housing and the impeller, which strongly resists axial movement of either part relative to the other.

[0026] In some examples, the outer surface of the front bearing housing may include knurling that projects radially and engages with the front engagement portion as part of a press-fit connection. The knurling may have a diameter exceeding the bore diameter of the impeller's engagement portion. Therefore, the knurling engages with the inner surface (the displaced portion) of the engagement portion during press-fitting and creates a strong frictional interface. Furthermore, the portion of the bearing housing located between the knurlings may have a smaller diameter, in some cases equal to or smaller than the bore diameter of the impeller's engagement portion, and thus require less force during press-fitting and reduce the risk of impeller damage compared to a uniform diameter exceeding the bore diameter of the impeller's engagement portion. In some examples, the knurling may have a barbed configuration, in which the knurling has an inclined lead-in surface followed by a notch (groove). The inclined lead-in surface facilitates insertion of the bearing housing into the bore of the impeller's engagement portion in a forward direction, while the notch provides a relatively sharp trailing edge that engages with the inner surface of the impeller and thus strongly resists retraction of the bearing housing from the impeller.

[0027] In some examples, press-fit connections between the impeller and rotor can eliminate the need for chemical adhesives (e.g., epoxy resin), thus eliminating the risk of accidental bearing seizure or the introduction of uneven mass distribution. Furthermore, press-fitting is less complex and can be performed faster than precision epoxy deposition; the equipment required for press-fitting is also significantly less expensive. Additionally, there is no risk of chemical incompatibility with liquid coolants or other materials in press-fitting. Press-fitting also produces more repeatable and consistent connections with a lower probability of failure.

[0028] Turning now to the figures, various apparatuses, systems and methods according to the non-limiting aspects of this disclosure will be described.

[0029] Figure 1 This is a conceptual diagram illustrating pump 100. Figure 1 Pump 100 is shown from a top-down view, illustrating the general positional and functional relationships between components as described below. However, this drawing is schematic in nature and is not intended to accurately or to scale any particular shape, size, or other structural detail. It should be understood that embodiments of pump 100 may differ from one another in various aspects. Some embodiments of pump 100 may have different numbers and arrangements of the illustrated components. Some embodiments of pump 100 may include... Figure 1 Other parts not shown in the diagram. Some embodiments of pump 100 may omit these components. Figure 1 One or more of the parts shown in the figure.

[0030] like Figure 1As shown, pump 100 includes a housing 110, a motor stator 120 (also referred to as "stator 120"), a control circuit system 125, a conduit 130 defining a liquid flow path 101, and an impeller / rotor sub-assembly 174 including an impeller 140, a rotor 142, and a shaft 143. The housing 110 and conduit 130 are shown as transparent to allow the view of other components. Additionally, some components (or portions thereof) that are obscured by other parts (e.g., contained within other parts) are shown in dashed lines; this is done to make it easier to visually distinguish between obscured and covered components. The components of pump 100 will be described in more detail below.

[0031] Housing 110 includes one or more walls or other support structures that support and at least partially enclose or house some other components of pump 100. Housing 110 may be a single part or made of multiple parts assembled together. In some examples, parts of housing 110 may also be integral parts of other parts of pump 100 and / or forming other parts of the pump. For example, portions of conduit 130 may also form parts of housing 110.

[0032] The motor stator 120 is configured to receive power from the control circuit system 125 and, in response, generate an alternating magnetic field that interacts with the rotor 142 of the impeller / rotor subassembly 174 to cause the rotor 142 (and thus the impeller 140 coupled to it) to rotate about its axis of rotation (in Figure 1 The rotor is depicted as rotating along axis 139. The motor stator 120 may include wire windings or other conductive materials to generate a magnetic field and / or a magnetically sensitive material, thereby transmitting and distributing the generated field around the impeller / rotor subassembly 174 in a desired pattern. In some examples, the motor stator 120 includes two parts: a first stator portion 120a and a second stator portion 120b, such as... Figure 1 As shown. These portions 120a and 120b are arranged on opposite lateral sides of the conduit 130. US11015608 B2 describes an example stator divided into two parts, and these stators can be used, for example, as a motor stator 120.

[0033] Control circuitry 125 is configured to control the operation of pump 100. In some examples, control circuitry 125 includes a printed circuit assembly (PCA) having various electronic components formed therein and / or mounted thereon, and / or additional components external to the PCA. In some examples, control circuitry 125 includes logic for driving the operation of pump 100. For example, control circuitry 125 may include a microcontroller. As another example, in addition to or instead of a microcontroller, control circuitry 125 may include discrete logic circuitry (digital or analog). Control circuitry 125 may also include sensors, such as temperature sensors, power usage sensors, humidity sensors (e.g., for leak detection), magnetic field (e.g., Hall effect) sensors, or other sensors. Control circuitry 125 may also include power delivery components, such as transistors or other switches (e.g., relays), capacitors, diodes, etc. In some examples, the control circuitry 125 may include communication components for communicating with external devices such as a system controller, baseboard management controller (BMC), rack controller, etc., for example, via cables (not shown) connected to the pump 100 and / or wirelessly (via, for example, Bluetooth, WiFi, etc.). The control circuitry 125 may be electrically connected to the motor stator 120 to provide electrical signals to the motor stator, thereby driving the operation of the motor stator 120. The control circuitry 125 may be connected to an external power source and / or an external controller via wires or cables (not shown).

[0034] The conduit 130 includes a wall that partially encloses a volume and defines a liquid flow path 101 through that volume, wherein the liquid flow path 101 is a path along which a liquid coolant (e.g., water or other coolant) flows as it passes through the pump 100. The conduit 130 includes: a pump inlet portion 131 (also referred to as “inlet 131”) having a first opening into the enclosing volume of the conduit 130; a pump outlet portion 132 (also referred to as “outlet 132”) having a second opening into the enclosing volume of the conduit 130; and an impeller chamber portion 133 located between the other two portions 131 / 132. The impeller chamber portion 133 houses an impeller 140 and is fluidly coupled to the inlet 131 and the outlet 132. Pump inlet portion 131 and pump outlet portion 132 may include structures for fluidly connecting the pump to a coolant line in a liquid cooling circuit, such as hose hooks, fittings, quick-connect couplings, and / or other liquid connection mechanisms familiar to those skilled in the art. In addition to the openings in inlet 131 and outlet 132, conduit 130 may be liquid-tight, thereby sealing the internal volume from the external environment, while these openings allow the enclosed internal volume to be fluidly connected to the external environment (e.g., to a coolant line in the liquid cooling circuit). In some examples, inlet 131 and outlet 132 may extend beyond the housing 110 of pump 100. In some examples, impeller chamber portion 133 is housed within housing 110.

[0035] The conduit 130 has a central longitudinal axis. This axis is coaxial with various other axes of other parts of the pump 100, including the axis of rotation of the rotor 142, the axis of rotation of the impeller 140 (described below), and the central longitudinal axis of the shaft 143, and therefore all these axes are... Figure 1 All are depicted by the same axis 139. Therefore, all these coaxial axes may be interchangeably referred to as axis 139 below. The liquid flowing through the conduit 130 as a whole flows in a direction parallel to axis 139, as described by... Figure 1 The dashed arrow indicates the flow path 101. Note that while traversing certain portions of the flow path 101 (e.g., when passing through impeller 140), the liquid (in addition to axial movement) may also circumferentially rotate around axis 139, but the overall or average movement of the liquid as a whole through conduit 130 is along a direction parallel to axis 139. The liquid flow path 101 in... Figure 1 The illustration shows how pump 100 is configured to flow liquid upon deployment; however, note that liquid is not necessarily part of pump 100 and is not necessarily present in all states of pump 100. For example, pump 100 may not contain liquid before being deployed in a liquid cooling circuit.

[0036] As described above, the impeller / rotor subassembly 174 includes an impeller 140 and a rotor 142 attached together and disposed within the duct 130. The impeller / rotor subassembly 174 also includes a shaft 143 to which the rotor 142 is rotatably attached, such that the rotor 142 and the impeller 140 coupled to the rotor can rotate about the shaft 143. The axes of rotation of the rotor 142, the axes of rotation of the impeller 140, the longitudinal axis of the shaft 143, and the longitudinal axis of the duct 130 are all coaxial, as described above. The shaft 143 is fixedly attached to the housing 110, and therefore, when the rotor 142 and the impeller 140 rotate about the shaft 143, they also rotate relative to the housing 110. The impeller 140 and the rotor 142 will be described in more detail below.

[0037] Impeller 140 is housed within conduit 130, specifically within impeller chamber 133 of the conduit. Impeller 140 is configured to drive liquid along flow path 101 through conduit 130 when rotated about axis 139. Impeller 140 includes impeller body 145 and blades 141 that project radially from impeller body 145 and helical along / around impeller body. Blade 141 helical along or around impeller body 145 means that blade 145 extends along a path axially through impeller body 145 while circumferentially surrounding impeller body 145 over at least a portion of that path; for example, the path may be helical. Blade 141 is configured to propel liquid axially through conduit 130 along flow path 101 when impeller 140 rotates.

[0038] The impeller body 145 is hollow (i.e., has an inner bore through it), and the rotor 142 is at least partially contained within the hollow interior of the impeller 140. Specifically, the impeller body 145 may have a generally hollow cylindrical shape with openings at both ends, one end of which is tapered / rounded. The shaft 143 also extends through the inner bore of the impeller body 145.

[0039] In some examples, the impeller body 145 and the impeller blades 141 are integrally connected, meaning they are formed together as two parts of the same monolithic body. The impeller body 145 can be formed from any solid material that can be formed into a desired shape. For example, the impeller body 145 can be formed from various plastics, which can be formed into a desired shape by injection molding, additive manufacturing (e.g., 3D printing), or other techniques. As another example, the impeller body 145 can be formed from various metals, which can be formed into a desired shape by casting, additive manufacturing (e.g., 3D printing), or other techniques.

[0040] Rotor 142 includes a magnetic portion 146, a rear bearing housing 148, and a front bearing housing 149. Rotor 142 is configured to rotate in response to a magnetic field generated by motor stator 120, thereby causing impeller 140 attached to the rotor to also rotate. Specifically, the magnetic portion 146 of rotor 142 is arranged to interact with the magnetic field generated by motor stator 120 to produce rotation of rotor 142. Thus, rotor 142 and motor stator 120 can together form an electromagnetic motor. Magnetic portion 146 may include permanent magnets and / or magnetically attractive (e.g., ferromagnetic) materials (e.g., iron, steel, etc.) capable of interacting with the generated magnetic field (e.g., being attracted or repelled by the generated magnetic field). In some examples, magnetic portion 146 includes a plurality of permanent magnets circumferentially distributed around axis 139 and arranged with alternating polarities.

[0041] The rotor 142 also includes a rear bearing housing 148 and a front bearing housing 149. The rear bearing housing 148 is located downstream of the magnetic portion 146, and the front bearing housing 148 is located upstream of the magnetic portion 146. Both the rear and front bearing housings contain various bearings to support the rotor 142 rotatably attached to the shaft 143. These bearings may include radial bearings, and in some examples, thrust bearings. As is well known to those skilled in the art, radial bearings are configured to primarily withstand radial forces, thereby promoting rotation of the rotor 142 about the shaft 143, while thrust bearings are configured to primarily withstand axial forces, thereby resisting axial movement of the rotor 142 along the shaft 143. Additionally, the front bearing housing 148 has a rigid structure configured to press-fit into a press-fit engagement portion 145a of the impeller body 145, as described below.

[0042] The rotor 142 is configured to be attached to the impeller 140 in the following manner: First, the rotor 142 is inserted at least partially into the inner bore of the impeller body 145 by passing the front bearing housing 149 through the rear opening of the bore in the forward direction and advancing the rotor 142 forward until the front bearing housing 148 contacts the press-fit engagement portion 145a of the impeller body 145. Thereafter, a force can be applied to press the impeller body 145 and the rotor 142 together until the front bearing housing 148 is press-fitted into the press-fit engagement portion 145a of the impeller body 145. That is, the impeller body 145 can be pressed rearward while the rotor 142 is pressed forward or remains stationary, or the rotor 142 can be pressed forward while the impeller body 145 is pressed rearward or remains stationary. For example, a hydraulic press or other press-fitting equipment can be used to apply the force to achieve the press-fit. During press fitting, the front bearing housing 148 is received in a cavity defined by the press-fit engagement portion 145a, which corresponds to a portion of the inner bore of the impeller 140. The front bearing housing 148 has a maximum diameter at its widest point(s), which exceeds the diameter of this cavity. Therefore, an interference fit exists between the front bearing housing 148 and the press-fit engagement portion 145a, and when the front bearing housing 148 is pressed into the cavity of the press-fit engagement portion 145a, the outward surface of the front bearing housing 148 engages with the inward surface of the press-fit engagement portion 145a (relative to which it slides, shifts, scrapes, and / or deforms). Thus, when the press fitting is complete, a strong frictional attachment is formed between the front bearing housing 149 and the impeller body 145.

[0043] In some examples, the front bearing housing 148 includes knurling 170. Knurling 170 projects radially and engages with a press-fit portion 145a as part of a press-fit connection. Knurling 170 may have a diameter exceeding the bore diameter of the engagement portion 145a. Therefore, knurling 170 engages with the inner surface (displaced portion) of the engagement portion 145a during press-fitting and creates a strong frictional interface. Furthermore, the portion of the bearing housing 148 located between the knurlings may have a smaller diameter, in some cases equal to or smaller than the bore diameter of the engagement portion 145a, and thus, compared to a case where the bearing housing 149 has a uniform diameter exceeding the bore diameter of the engagement portion 145a, less force may be required during the press-fitting process, and the risk of damage to the impeller 140 may be reduced. In some examples, knurling 170 may have a barbed configuration, in which the knurling has an inclined lead-in surface followed by a notch (groove). The inclined inlet surface facilitates insertion of the bearing housing 149 into the bore of the engagement portion 145a in the forward direction, while the cut provides a relatively sharp trailing edge that can bite into the inner surface of the engagement portion 145a and thereby strongly resist retraction of the bearing housing 149 from the impeller 140. In some examples, the knurling 170 is arranged in one or more layers, and in the presence of multiple layers, the knurling can be stacked one on top of the other in the axial direction. In some examples, within each layer, the knurling 170 is uniformly distributed around the periphery of the bearing housing 149. In some examples, the portion of the bearing housing 149 extending between adjacent knurling 170 includes straight sections, such that the knurling and the straight sections together form a shape with a polygonal profile, wherein the knurling 170 is positioned at the corners or points of the polygon. For example, in some embodiments, each layer of knurling 170 may include six knurlings 170 uniformly arranged around the periphery, and these knurlings, together with the straight sections extending therebetween, form a shape with a generally hexagonal profile. In some examples, each layer has fewer knurling 170s (e.g., three, four, five, etc.), while in other examples, each layer has more knurling 170s (e.g., seven, eight, etc.). In some examples, each layer has the same number of knurling 170s as the other layers. In other examples, the number of knurling 170s per layer can differ between layers. In some examples, the knurling 170s of each layer are axially aligned with the knurling 170s of other layers. In other examples, one or more of the knurling 170s in one layer are not aligned with the knurling of another layer. In some examples, the shape and size of each knurling 170 is similar to the other knurling 170s, while in other examples, the knurling 170s can have different or irregular shapes / sizes, whether within a layer or between layers. In some examples, there are two layers of knurling 170s stacked axially. In other examples, there is one layer; in other examples, there are three or more layers.

[0044] Note that the term “press fit” and similar / derived phrases used herein broadly refer to any of the various techniques used to mechanically attach two parts together, creating an interference fit by applying force to press one of the two parts into the cavity of the other part, thereby creating a frictional attachment between them. These techniques, as examples of “press fit” as used herein, can include cold press fit, hot press fit, ultrasonic riveting, or other techniques. While applying force to press the parts together is the defining characteristic of “press fit” as used herein, press fit is not necessarily the only mechanism that can be operationally joined together. For example, in some cases, heat can be applied to one or both parts (e.g., to impeller 140) before or during press fit to soften the parts and / or temporarily expand their dimensions. As another example, vibration (e.g., ultrasonic vibration in some cases) can be applied to the parts during or after press fit, which is also known as ultrasonic riveting.

[0045] like Figure 1 As shown, shaft 143 is secured to conduit 130 and housing 110 via front support 144 and rear support 151. Front support 144 engages and holds the front portion of shaft 143 and is coupled to the wall of conduit 130. Rear support 151 engages and holds the rear portion of shaft 143 and is also coupled to the wall of conduit 130. (In this document, relative to...) Figure 1 The orientation of the illustrated pump 100 uses "front" and "rear," with the inlet side being the "front" side and the outlet side being the "rear" side. However, these terms are intended only to aid understanding and not to limit. In particular, in some examples of the pump 100, the orientations of supports 144 and 151 may be reversed, with support 144 closer to outlet 132 and support 151 closer to inlet 131. In such cases, the terms "front" and "rear" as used herein will be reversed with respect to these components.

[0046] In some examples, pump 100 further includes an adjustment mechanism 136. Adjustment mechanism 136 connects shaft 143 to rear support 151. Adjustment mechanism 136 is actuable and, when actuated, changes the position of shaft 143 relative to rear support 151, and thus also changes its position relative to impeller chamber 133. More specifically, adjustment mechanism 136 is configured to translate the rear end of shaft 143 relative to rear support 151 along axis of rotation 139, which in turn translates the front end of shaft 143 relative to front support 144. Since shaft 143 is connected to rotor 132 and rotor 132 is connected to impeller 140, when shaft 143 translates along axis 139, this also translates impeller 140 along axis 139 relative to duct 130. Adjusting the position of impeller 140 in this way changes the clearance between blade 141 and the wall of duct 130, particularly near the front end of impeller 140. This allows for a smaller clearance between the blade 141 and the guide tube 130, which improves performance without requiring high precision in the parts, which would unnecessarily increase costs. In some examples, the regulating mechanism 136 may include any regulating mechanism described in U.S. Patent Application No. 17 / 977,200, filed October 31, 2022, entitled “AXIAL PUMP WITH ADJUSTABLE IMPELLER,” the entire contents of which are incorporated herein by reference.

[0047] Turn now Figures 2 to 17 Another example pump, in the form of pump 400, will be described below. Pump 400 is an example configuration of pump 100 described above. Therefore, some components of pump 400 are similar to the corresponding components already described above (e.g., their example configurations), and thus the description of the components of pump 100 above applies to similar components of pump 400, and therefore repetitive descriptions of certain aspects of pump 400 can be omitted. Corresponding components can be referred to using reference numerals with the same last two digits (e.g., 110 and 410). It should be understood that pump 400 is merely one possible configuration of pump 100, and pump 100 is not limited to pump 400. Similarly, the various components of pump 400 are examples of the corresponding various components of pump 100, but the various components of pump 100 are not limited to the corresponding components of pump 400.

[0048] Various aspects of pump 400 are visible in multiple figures, and different figures may better illustrate certain aspects compared to those showing other aspects. Therefore, they are not described below in a strict order. Figures 2 to 17 For each of these, the various aspects of pump 400 will be described below with reference to some of the figures most relevant to the particular aspect being discussed. Figure 2 , Figure 3 and Figure 17Views of the complete pump 400 are shown, including perspective, exploded view and cross-sectional view. Figures 4 to 16 The isolated portions of pump 400 are shown in various views: Figure 4 The impeller chamber subassembly 473 of the pump 400 is shown in an exploded partial cross-sectional view; Figures 5 to 7 The rotor 442 and shaft 443 of the pump 400 in various assembly states are shown in exploded and perspective views. Figures 8 to 10 The front bearing housing 449 of the rotor 442 is shown in various assembly states; Figures 11 to 14 The rear bearing housing 448 of the rotor 442 in various assembly states is shown; and Figure 15 and Figure 16 Cross sections of the impeller / rotor assembly 474 are shown in both partially assembled and fully assembled states.

[0049] like Figure 2 and Figure 3 As shown, pump 400 includes multiple subassemblies, including a first stator subassembly 471, a second stator subassembly 472, an impeller chamber subassembly 473, an inlet subassembly 475, and an outlet subassembly 476. Each of these subassemblies will be described in more detail below.

[0050] like Figure 2 and Figure 3 As shown, the first stator subassembly 471 and the second stator subassembly 472 respectively include a first stator portion 420a and a second stator portion 420b. Additionally, the first stator subassembly 471 and the second stator subassembly 472 include PCBs 425, which constitute a split PCA, such as the split PCA described in U.S. Patent Application No. 17 / 976,406, filed October 28, 2022, entitled “AXIAL PUMP WITHSPLIT PRINTED CIRCUIT BOARD ASSEMBLY,” the entire contents of which are incorporated herein by reference. PCBs 425 are electrically connected to the first stator portion 420a and the second stator portion 420b, for example, via soldering or other electrical connections. Figure 3 As shown, the first stator sub-assembly 471 and the second stator sub-assembly 472 are located on opposite sides of the impeller chamber sub-assembly 473. Therefore, during the assembly of the pump 400, the first stator sub-assembly 471 and the second stator sub-assembly 472 can be arranged as follows: Figure 3Positioned as shown in the exploded view, stator subassemblies 471 and 472 can then be moved laterally (in the directions indicated by arrows 402 and 403) to bring stator subassemblies 471 and 472 together around impeller chamber subassembly 473. Once assembled in this way, stator portions 420a and 420b are positioned adjacent to and radially surround impeller chamber 433 (except for small unenclosed areas at the top and bottom of impeller chamber 433), as shown in the exploded view. Figure 2 As shown. In addition, when the first stator sub-assembly 471 and the second stator sub-assembly are connected to the impeller chamber sub-assembly 473, the PCB 425 is electrically connected.

[0051] like Figure 3 and Figure 4 As shown, the impeller chamber subassembly 473 includes an impeller chamber 433 and an impeller / rotor subassembly 474 (at least partially) housed within the impeller chamber 433. The impeller chamber 433 includes a front portion 433a and a rear portion 433b. The front portion 433a includes an aperture 467, and the rear portion 433b includes an aperture 450. Figure 4 As indicated by the arrows, when assembling the impeller chamber subassembly 473, the front portion 433a and the rear portion 444b are joined together, wherein the impeller / rotor subassembly 474 is partially positioned within the bore 467 and partially positioned within the bore 450. Figure 3 As shown, the front portion 433a of the impeller chamber includes a mating portion 438 that defines the rear opening of the bore 467. Figure 6 As shown, the rear portion 433b of the impeller chamber includes a joining portion 455 configured to engage with a joining portion 438 of the front portion 433a (e.g., received in the joining portion of the front portion) to join the front portion 433a and the rear portion 433b together. The joining portion 455 surrounds and defines an aperture 450.

[0052] like Figure 4 As shown, the impeller / rotor subassembly 474 includes an impeller 440 coupled to a rotor 442, which in turn is coupled to a shaft 443. The impeller 440 includes an impeller body 445 and blades 441, the blades projecting radially from the impeller body 445 and rotating axially and circumferentially along and around the outer surface of the impeller body 445. The shaft 443 includes a front end 443a and a rear end 443b.

[0053] like Figures 5 to 7As shown, rotor 442 includes a bearing tower 460 comprising a bearing tower shaft 461, a front bearing housing 449 attached to a front end of the bearing tower shaft 461, and a rear bearing housing 448 attached to a rear end of the bearing tower shaft 461. Rotor 442 also includes magnets 446 distributed around the tower shaft 461 and fixedly coupled to the bearing tower 460 for movement with the bearing tower 460. In this example, the rear bearing housing 448 is integrally connected to the bearing tower shaft 461, while the front bearing housing 449 is initially separate from the bearing tower shaft 461 and subsequently attached to the bearing tower shaft, for example, via adhesive or other fasteners. However, in other examples, the bearing housing may be formed separately from the tower shaft 461 and subsequently attached to the tower shaft. Bearing housings 448 and 449 each house bearings 447 that rotatably connect rotor 442 to shaft 443. Specifically, as Figures 5 to 16 As shown, the front bearing housing 449 includes a front radial bearing 447a, while the rear bearing housing 448 includes a rear radial bearing 447b and a rear thrust bearing 447c.

[0054] like Figure 8 As shown, the front end of the front bearing housing 449 has a cavity 469a, and as Figure 9 As shown, the front radial bearing 447c is disposed in this cavity 469a. (As indicated...) Figure 11 As shown, the rear bearing housing 448 has a first cavity 464a, and as Figure 12 As shown, the rear radial bearing 447a is disposed in this first cavity 464a. As... Figure 11 As shown, the rear bearing housing 448 has a second cavity 464b, and as Figure 13 As shown, the rear thrust bearing 447b is disposed in this second cavity 464b, located behind the rear radial bearing 447a. Figure 5 and Figure 17 As shown, shaft 443 includes a flange 435 disposed between a rear radial bearing 447a and a rear thrust bearing 447b, wherein the thrust bearing 447b axially supports and abuts against the flange 435.

[0055] Rotor 442 is assembled as follows. For example... Figure 6As shown, a magnet 446 is positioned on a bearing tower 460 around a tower shaft 461, and a front bearing housing 449 is then attached to the front end of the tower shaft 461 to secure the magnet 446 in place. The presence of a front bearing housing 449 on one side of the magnet 446 and a rear bearing housing 448 on the opposite side of the magnet prevents the magnet 446 from axially moving away from the tower shaft 461. In some examples, the magnet 446 is attached as a unit, for example by magnetic attraction, adhesive, fusion / welding, and / or mechanical fasteners (not shown). In some examples, the magnet can also be more securely attached to the bearing tower 460, for example by applying adhesives, mechanical fasteners, etc.

[0056] Furthermore, in some examples, the front bearing housing 449 and the rear bearing housing 448 not only prevent the magnet 446 from moving axially away from the shaft 461, but also engage with and hold the magnet 446 to prevent it from moving radially away from the shaft 461. For example, as Figure 10 As shown, the rear end of the front bearing housing 449 may have a cavity 469b, which is configured to receive the protrusion 446a of the magnet 446 (see Figure 1). Figure 5 This helps to secure magnet 446 to bearing tower 460. Similarly, as Figure 5 As shown, the rear bearing housing 449 also has a cavity 464c, which is configured to engage with a protrusion 446b protruding from the other end of the magnet 446 to help secure the magnet 446 to the bearing tower 460.

[0057] After the magnet 446 has been assembled onto the bearing tower 460, the front radial bearing 447c can be inserted into the cavity 496a of the front bearing housing 449, as follows. Figure 9 As shown. Alternatively, the rear radial bearing 447a can be inserted into the first cavity 464a of the rear bearing housing 448, as shown. Figure 12 As shown (this can be done before or after assembling magnet 446 into bearing tower 460). Additionally, as... Figure 6 As shown, in some examples, the inner race 447b' of the thrust bearing 447b can be assembled onto the shaft 443 by press fitting.

[0058] Next, the front end of shaft 443 can be inserted into the inner bore 460a passing through bearing tower 460. Bore 460a axially passes through the center of shaft 461 (see...). Figure 11 And aligned with bore 469c of front bearing housing 449 (see...) Figure 8 During this insertion, shaft 443 also passes through bore 469c of front bearing housing 449 and through the central openings in front radial bearing 447c and rear radial bearing 447a.

[0059] Before or after inserting the shaft 443, the remainder of the thrust bearing 447b can be inserted onto the rear end of the shaft 443 and into the second cavity 464b of the rear bearing housing 448. Next, the spring clip retainer 463 is inserted into the rear bearing housing 448 to secure the thrust bearing 447b therein, as... Figure 14 As shown. Washer 465 can be placed between thrust bearing 447b and retainer 463.

[0060] like Figure 7 As shown, the clip and spring retainer 466 can be attached to the shaft 443 at the front of the front bearing housing 449. The spring of the retainer 466 applies rearward pressure on the front radial bearing 447c, which helps to hold the front radial bearing 447 in its mounting position within the cavity 469a. The use of the spring avoids loosening or play due to tolerance accumulation in the rotor 442.

[0061] After the above process, rotor 442 is fully assembled onto shaft 443, resulting in... Figure 7 The state shown.

[0062] After assembling the rotor 442, the rotor 442 (and the shaft 443 connected to it) and the impeller 400 can be assembled together to form the impeller / rotor subassembly 447. This assembly process can be performed as follows.

[0063] First, insert the front part of the rotor 442 into the inner bore of the impeller 440 and push it forward until the front bearing housing 449 reaches the engagement portion 445a, as shown. Figure 16 As shown. The widest diameter of rotor 442 can be smaller than the widest diameter of the inner bore of impeller body 445, and therefore rotor 442 can be inserted into the bore with relatively little resistance until front bearing housing 449 reaches engagement portion 445a. Once front bearing housing 449 reaches engagement portion 445a, rotor 442 will resist further forward propulsion because front bearing housing 449 has a maximum outer diameter exceeding the inner bore diameter of engagement portion 445a (i.e., front bearing housing 449 and engagement portion 445a have an interference fit).

[0064] Next, the impeller 440 and rotor 442 can be axially pressed together, for example, by a hydraulic press or other press-fitting equipment, so that the front bearing housing 449 is press-fitted into the mating portion 445a, as shown below. Figure 17 As shown.

[0065] Return to Figures 8 to 10 In this example, the front bearing housing 449 has twelve knurled edges 470. These knurled edges 470 are arranged in two axially stacked layers, namely a first layer 470a and a second layer 470b, as shown below. Figure 10As shown. Each of these layers includes six knurls 470 distributed around the perimeter of the front bearing housing 449, as Figure 8 shown. In other examples, a different number of knurls 470 can be provided per layer, and / or a different number of layers can be used. The outer diameter of the front bearing housing 449 between two opposite knurls 470 is d1, as Figure 8 shown. As Figure 16 shown, the inner diameter of the engagement portion 445a is d2. Since d2 < d1, the front bearing housing 449 and the engagement portion 445a have an interference fit, and when the two are press-fitted together, the knurls 470 engage and displace portions of the inner surface of the engagement portion 445a, thereby forming a secure mechanical attachment. As Figure 10 shown, each knurl 470 has a barb configuration with an inclined introduction portion 470c and a notch 470d. The inclined introduction portion 470c allows for easier insertion into the engagement portion 445a during press-fitting, while the notch 470d creates a sharp edge that can dig into the engagement portion 445a and resist backward movement of the front bearing housing 449 relative to the impeller 440.

[0066] As Figure 8 and Figure 9 shown, there can be flat segments 449e extending between pairs of adjacent knurls 470. The diameter of the front bearing housing 449 in the area between the knurls 470 (or in other words, the distance from one of the flat segments 449e to the diametrically opposite flat segment 449e) is d3. In the illustrated example, d3 is equal to or less than d2. Thus, these portions of the front bearing housing 449 between the knurls 470 can be relatively easily inserted into the engagement portion 445a. In other words, in some examples, only the knurls 470 interfere with the engagement portion 445a, and thus the amount of force required for press-fitting can be reduced (compared to if the entire front bearing housing 449 had a diameter of d2), and the likelihood of damaging the impeller 440 can be reduced. Additionally, the strength of the attachment can be stronger when only the knurls 470 have a diameter of d2 compared to if the entire front bearing housing 449 had a diameter of d2. In other examples, d3 is slightly less than d2. In other examples, d3 is slightly greater than d2.

[0067] Once the impeller / rotor subassembly 474 is assembled, it can be inserted into the conduit 430, and the shaft 443 can be coupled to the conduit 430. Thus, when the impeller 440 rotates about the shaft 443, the impeller also rotates relative to the conduit 430. As Figure 4 and Figure 17As shown, when the impeller chamber subassembly 473 is assembled, the impeller 440 is housed within the impeller chamber 433, wherein the front end 443 of the impeller shaft 443 is connected to the front portion 433a of the impeller chamber 433 and the rear end 443b of the shaft 443 is connected to the rear portion 433b of the impeller chamber 433. More specifically, as Figure 17 As shown, the front end 443a of the shaft 443 of the impeller 440 is inserted into the hub 484 of the front support member 444. The front support member 444 is connected to the wall of the impeller chamber 433. Therefore, when the front end 443a is engaged with the front support member 444, the front support member 444 supports the shaft 443 relative to the impeller chamber 433. Similarly, the rear end 443b of the shaft 443 is inserted into and engaged with the rear support member 451 of the rear portion 433b of the impeller chamber, as shown. Figure 17 As shown. Specifically, the adjusting mechanism 436 is used to connect the shaft 443 to the rear support 451. The adjusting mechanism 436 includes a nut 436a, a retaining screw 436b for the shaft 443, and a socket 436c in the end of the shaft 443. The nut 436a is attached to the nut holding portion 453 of the rear support 451 and receives the retaining screw 436b, such that rotation of the shaft 443 relative to the nut 436a causes the shaft 443 to translate relative to the rear support 451. The socket 436c receives a tool to allow the shaft 443 to rotate in this manner.

[0068] like Figure 4 and Figure 17 As shown, the rear support 451 includes a cylinder 452 surrounding the bore 450, a nut-retaining portion 453 attached to one end of the cylinder 452, and an attachment portion 454 extending radially from the cylinder 452 to attach the cylinder 452 to the engagement portion 455. Although not visible in the figure, the attachment portion 454 is arranged not to obstruct the flow of liquid through the chamber 433, wherein the liquid flows through the space between the engagement portion 455 and the cylinder 452 and flows around the attachment portion 454.

[0069] The impeller chamber 433 is also connected to various support structures and / or includes various surfaces that form part of the housing 410 and facilitate the connection of other sub-assemblies. For example, as Figure 4 As shown, the rear portion 433b includes a fastener holder 459 having a hole 458 to receive a fastener 477. Figure 3 and Figure 4 As shown, the front portion 433a includes a hole 437, and when the front portion 433a and the rear portion 433b are joined together, the hole 437 is aligned with the hole 458. Therefore, as Figure 3 As shown, fastener 477 is inserted through holes 437 and 458 to secure the front portion 433a and the rear portion 433b in the connected state. Additionally, as... Figure 4As shown, the rear portion 433b also includes holes 457 that receive fasteners 479, such as... Figure 3 As shown. Similarly, the front portion 433a includes a hole 485, as... Figure 4 As shown, to receive fastener 479, as Figure 3 As shown. These fasteners 479 are used to connect various sub-components together, as described below. In some examples, the front portion 433a may also include holes 481, which can be used to fill the pump 400 with epoxy resin after assembly to make the pump 400 waterproof and also to facilitate the transfer of heat from the pump 400 components to the coolant by removing the air gap. Furthermore, the impeller chamber 433 is connected to the housing portions 410i, 410j, 410k, and 410L.

[0070] The inlet subassembly 475 includes an inlet 431 and a vibration isolator 466. The outlet subassembly 476 includes an outlet 432 and a vibration isolator 466. In the illustrated example, inlet 431 and outlet 432 include hose barb connections. In other examples, other types of fluid connections may replace hose barb connections. Pump 400 may be coupled to another device (e.g., the chassis of a computing device in which pump 400 is housed) via vibration isolator 459. Vibration isolator 459 may be rubber, silicone, or other compliant material that helps absorb vibrations generated by pump 400 and prevents (or reduces) the transmission of these vibrations to the device in which pump 400 is housed. Figure 3 As shown, outlet 432 includes a connecting portion 487. This connecting portion 487 is configured to engage with a connecting portion 456 of the rear portion 433b of the impeller chamber, as... Figure 17 As shown. Figure 17 As shown, outlet 432 may also include outlet guide vanes (OGV) 434, which include fins 434a. The OGV 434 guides the liquid flow as it exits the impeller chamber 433 and enters outlet 432. This OGV 434 helps to straighten the liquid flow, removing or reducing some of the circumferential motion introduced by the rotation of impeller 440, causing the fluid to move primarily or only axially as it exits outlet 432.

[0071] Additionally, each of the inlet subassembly 475 and the outlet subassembly 476 includes a portion of the housing 410. For example... Figure 3 As shown, the inlet subassembly 475 and the outlet subassembly 476 can be positioned on opposite axial sides of the impeller chamber subassembly 473. Therefore, during the assembly of the pump 400, the inlet subassembly 475 and the outlet subassembly 476 can be positioned as follows: Figure 3The components are positioned as shown and then moved toward each other (in the directions indicated by arrows 404 and 405) until inlet 431 is fluidly connected to one side of impeller chamber 433 and outlet 432 is fluidly connected to the other side of impeller chamber 433. In some examples, this assembly step can be performed after the two stator sub-assemblies 471 and 472 have already been assembled onto impeller chamber sub-assembly 473. Once inlet 431, outlet 432, and impeller chamber 433 are connected, they form conduit 430 through which liquid coolant can flow along the central axis 439 of the conduit.

[0072] like Figure 2 and Figure 3 As shown, pump 400 includes a housing 410. The housing 410 may be composed of multiple interconnected portions. Specifically, the aforementioned subassemblies may include these portions of housing 410. In particular, housing 410 includes an inlet end wall portion 410a and side wall portions 410b and 410c connected to the inlet end wall portion 410a. These portions 410a-c are part of an inlet subassembly 475. Housing 410 further includes an outlet end wall portion 410f and side wall portions 410g and 410e. These portions 410e-g are part of an outlet subassembly 475. When assembled, the aforementioned portions 410a-c and 410e-g define the outer peripheral sidewalls of housing 410. Housing 410 also includes a top portion 410d connected to a portion of a first stator subassembly 471 and a top portion 410h connected to a portion of a second stator subassembly 472 and a top portion 410h of a second stator portion 420b. The housing also includes housing top portions 410i, 410j, 410k, and 410L, which are coupled to the conduit 430 and are part of the impeller chamber subassembly 473. Top portions 410d, 410h, and 410i-410L form the top surface of housing 410. Note that the top surface of housing 410 is not necessarily uniform and does not necessarily completely cover the entire pump 400. For example, the tops of stator portions 420a and 420b may be exposed and substantially coplanar with the top surface of housing 410 (this can allow the height dimension of pump 400 to be reduced to the absolute minimum possible for a given size of stator 420). Some of the housing portions may include holes 478 (only some are marked) arranged to receive fasteners 479 to join the subassemblies together. For example, in some embodiments (including...) Figure 3 In the embodiment illustrated herein, the impeller chamber subassembly 473 includes fasteners 479 in the form of pins (e.g., spring-biased pushers), and each of these fasteners can be inserted into a hole 478 in one or more subassemblies to secure the respective subassemblies together. A single fastener 479 can be inserted through two holes 478 in two different subassemblies, for example, Figure 3The fastener marked 479' can be inserted into the two holes marked 478', which are part of the stator subassembly 472 and the outlet subassembly 476. Other fasteners 479 and holes 478 can be connected similarly.

[0073] The bottom portion of housing 410 (which is generally not visible in the figure and is not labeled herein) may be constructed similarly to the top portion of housing, therefore repeated descriptions of these portions are omitted.

[0074] Figure 18 The illustration includes a schematic diagram of example system 580 and electronic device 590. System 580 includes electronic device 590 and a liquid cooling circuit 589 coupled to electronic device 590. The system may also include additional electronic devices (not shown). For example, system 580 may include one or more racks for the electronic devices. For ease of description, electronic device 590 is illustrated in a state of being installed in system 580; however, it should be understood that electronic device 590 may be configured to be separate from system 580.

[0075] The liquid cooling circuit 589 includes a pump 500 (described below), one or more coolant supply lines 587, one or more coolant return lines 588, and one or more additional cooling circuit components 583, such as heat exchangers, rack-level, row-level or data center-level coolant distribution units, coolers, or other cooling components familiar to those skilled in the art.

[0076] Electronic device 590 includes: a PCB 595, such as a substrate or motherboard of a computing device; and a chassis 594 that supports and houses the PCB 595. PCB 595 includes electrical components 591, such as a processor, power supply unit, storage device, hardware accelerator, or any other electrical component. Electronic device 590 further includes a cold plate 592 thermally coupled to the electrical components 591.

[0077] Electronic device 590 further includes a pump 500 disposed in chassis 594. Pump 500 can be any of the pumps described above, such as pump 100 and pump 400. Pump 500 is fluidly connected to cold plate 592 via coolant line 596. Pump 500 is electrically connected to PCB 595 via wires / cables connected to connector 598 of PCB 595. Thus, PCB 595 can supply power to pump 500 and / or communicate with pump. Pump 500 includes inlet 531, which can be connected to liquid coolant supply line 587 of liquid cooling circuit 589 of system 580, which supplies liquid coolant to pump 500. Pump 500 outlet 532 is connected to coolant line 596. The outlet of the cold plate 592 can be connected to a liquid coolant return line 588 of the liquid cooling circuit, which returns the liquid coolant to the rest of the circuit for final cooling (e.g., at a heat exchanger). Therefore, when the electronic device 590 is installed in the system 580 and fluidly connected to the system's liquid cooling circuit 589, liquid coolant from the circuit 589 can flow through the pump 500 and the cold plate 592. Specifically, the pump 500 can be configured such that (or at least facilitate) the flow of liquid coolant through the cold plate 592 to cool the electrical component 591.

[0078] It should be understood that both the general description and the detailed description provide illustrative examples of an inherent nature and are intended to provide an understanding of this disclosure without limiting its scope. Various mechanical, compositional, structural, electronic, and operational changes may be made without departing from the scope of this specification and the claims. In some instances, well-known circuits, structures, and techniques have not been shown or described in detail to avoid obscuring these examples. In two or more drawings, the same numerals denote the same or similar elements.

[0079] Furthermore, unless the context otherwise indicates, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. Additionally, the terms “comprises,” “comprising,” “includes,” etc., specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups. Unless otherwise specifically stated, components described as connected may be directly electrically or mechanically connected, or may be indirectly connected via one or more intermediate components. Unless the context otherwise indicates, mathematical and geometric terms are not necessarily used according to their strict definitions, as those skilled in the art will understand that, for example, substantially similar elements acting in substantially similar ways may readily fall within the scope of descriptive terms, even if those terms have strict definitions.

[0080] And / or: Occasionally, the phrase “and / or” is used in conjunction with a list of enumerated items in this text. This phrase means that any combination of items in the list can be included—from a single item to all items, and any permutation in between. Thus, for example, “A, B and / or C” means “one of {A}, {B}, {C}, {A, B}, {A, C}, {C, B}, and {A, C, B}.”

[0081] An element and its related aspects described in detail with reference to an example may, where feasible, be included in other examples that do not specifically show or describe them. For example, if an element is described in detail with reference to an example and not with reference to a second example, then that element may still be claimed as being included in the second example.

[0082] Furthermore, unless otherwise stated herein or implied by the context, the use of approximate terms such as “basically,” “roughly,” “about,” “around,” “probably,” etc., should be understood to mean that mathematical precision is not required, but rather refers to a range of variation that includes, but is not strictly limited to, the stated values, properties, or relationships. In particular, apart from any range explicitly stated herein (if any), the range of variation implied by the use of such approximate terms includes at least any insignificant variations and those that are typical for items of the type discussed due to manufacturing tolerances or other tolerances in the relevant field. In any case, unless otherwise indicated, the range of variation may include values ​​within ±1% of the stated values, properties, or relationships.

[0083] Given the disclosure herein, further modifications and alternative examples will be apparent to those skilled in the art. For example, apparatus and methods may include additional components or steps omitted from the figures and description for clarity of operation. Accordingly, this description is to be interpreted only as illustrative and intended to teach those skilled in the art the general manner of performing this teaching. It should be understood that the various examples shown and described herein are to be considered exemplary. Those illustrated and described herein may be replaced by elements and materials, and arrangements of such elements and materials, components and processes may be reversed, and certain features of this teaching may be utilized independently, all of which will be apparent to those skilled in the art upon benefiting from the description herein. Changes may be made to the elements described herein without departing from the scope of this teaching and the appended claims.

[0084] It should be understood that the specific examples described herein are non-limiting, and modifications can be made to the structure, dimensions, materials, and methods without departing from the scope of this teaching.

[0085] Considering the specification and practice of the invention disclosed herein, other examples based on this disclosure will be apparent to those skilled in the art. The specification and examples are intended to be illustrative only, and the following claims will have their broadest scope, including equivalents under applicable law.

Claims

1. An axial flow pump for delivering liquid coolant to cool electronic devices, the axial flow pump comprising: A conduit that defines a flow path from the inlet of the conduit to the outlet of the conduit; Impeller, the impeller being located within the duct; A shaft, which is disposed in and connected to the conduit; The rotor is disposed inside the hollow interior of the impeller. The rotor includes a magnetic part, a front bearing housing, and a rear bearing housing. The front bearing housing and the rear bearing housing include bearings that rotatably connect the rotor to the shaft. The rotor is connected to the impeller by a press fit attachment between the front bearing housing and the impeller. A motor stator configured to drive the rotor to rotate about the shaft, the impeller rotating together with the rotor about a rotation axis extending parallel to the flow path.

2. The axial flow pump as described in claim 1, in, The front bearing housing includes knurling that protrudes from the outer surface of the front bearing housing.

3. The axial flow pump as described in claim 2, in, The knurling is arranged in two or more layers stacked axially along the outer surface of the front bearing housing.

4. The axial flow pump as described in claim 3, in, Each of the layers includes a plurality of knurling evenly distributed around the periphery of the front bearing housing.

5. The axial flow pump as described in claim 4, in, Each of the layers comprises six knurled patterns.

6. The axial flow pump as described in claim 2, in, The impeller includes a mating portion configured to engage with the front bearing housing, the mating portion including a bore having an inner diameter; and The knurling includes a pair of knurlings that are diametrically opposed to each other, and the diameter of the front bearing housing at the pair of knurlings exceeds the inner diameter of the hole in the engagement portion.

7. The axial flow pump as described in claim 6, in, The front bearing housing includes an intermediate portion located between adjacent knurlings in the knurling, and the diameter of the front engagement portion between a pair of intermediate portions that are diametrically opposed to each other is equal to or less than the inner diameter of the hole in the engagement portion.

8. The axial flow pump as described in claim 2, in, The knurling has a barbed configuration.

9. The axial flow pump as described in claim 1, in, The rotor includes a bearing tower, which includes a front bearing housing, a rear bearing housing, and a bearing tower shaft extending between the front bearing housing and the rear bearing housing. The shaft of the pump extends through the bearing tower shaft, and the magnetic portion is coupled to the bearing tower and distributed around the bearing tower shaft.

10. The axial flow pump as described in claim 1, in, The bearing includes a front radial bearing disposed in the front bearing housing, a rear radial bearing disposed in the rear bearing housing, and a rear thrust bearing disposed in the rear bearing housing.

11. The axial flow pump as described in claim 1, in, The rotor is mechanically coupled to the impeller via the press-fit attachment without any adhesive or bonding agent to attach the rotor to the impeller.

12. The axial flow pump as described in claim 1, in, The impeller includes an impeller body and one or more blades, the one or more blades protruding radially from the impeller body and rotating axially and circumferentially along the impeller body.

13. An electronic device comprising: Printed circuit board (PCB); Electrical components, which are connected to the PCB; A chassis that houses the PCB; A cold plate, thermally coupled to the electrical component; as well as The axial flow pump as described in claim 1 is disposed within the chassis, wherein the axial flow pump's conduit is fluidly connected to the cold plate.

14. The electronic device as claimed in claim 1, in, The electronic device is a server, and the electrical component is a processor.

15. A system comprising: Multiple information processing devices, each information processing device including a chassis, a printed circuit board disposed in the chassis, and electrical components connected to the PCB; And a cold plate, which is thermally coupled to the electrical component; Multiple examples of the axial flow pump as claimed in claim 1, wherein each of the axial flow pumps is disposed in the chassis of one of the information processing devices, and the conduit of the respective axial flow pump is fluidly connected to the cold plate of the respective information processing device; A liquid cooling circuit includes a liquid coolant supply line configured to supply liquid coolant to the axial flow pump, a liquid coolant return line configured to return liquid coolant from the pump, and a heat exchanger configured to cool the liquid coolant.

16. The system of claim 15, comprising: in, The axial flow pump is individually controllable so as to individually regulate the flow rate of the liquid coolant passing through the information processing device.

17. A method of manufacturing an axial flow pump, the method comprising: A rotor is provided, the rotor including a magnetic portion, a front bearing housing and a rear bearing housing, the front bearing housing and the rear bearing housing including bearings to rotatably connect the rotor to a shaft; The rotor is inserted into the hollow interior of the impeller; as well as The rotor and the impeller are pressed together using a press-fitting device, and the front bearing housing is press-fitted into the joint portion of the impeller.

18. The method of claim 17, wherein, The rotor is mechanically attached to the impeller by press fitting, without the need for adhesives or bonding agents to bond the rotor to the impeller.

19. The method of claim 17, further comprising coupling the rotor to the shaft before inserting the rotor into the hollow interior of the impeller.

20. The method of claim 19, comprising: The assembly of the impeller, the rotor, and the shaft is inserted into the impeller chamber; The first end of the impeller shaft is inserted into the hub of the first support member connected to the impeller chamber; The second end of the shaft is connected to the second support member, and the second support member is connected to the impeller chamber; A first stator sub-assembly is positioned on a first lateral side of the impeller chamber and a second stator sub-assembly is positioned on a second lateral side of the impeller chamber, the first stator sub-assembly and the second stator sub-assembly comprising two parts of a motor stator configured to drive the impeller to rotate; The first stator subassembly and the second stator subassembly, as well as the impeller chamber, are assembled by moving the first stator subassembly and the second stator subassembly toward the impeller chamber, such that the impeller chamber is trapped between the first stator subassembly and the second stator subassembly. as well as The pump inlet structure is connected to one end of the impeller chamber and the pump outlet structure is connected to the opposite end of the impeller chamber, the pump inlet structure, the pump outlet structure and the impeller chamber forming a conduit that defines the flow path of the axial flow pump.

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