WO2025035062A1 - Rotor assembly cooling system - Google Patents

Abstract

A rotor assembly for a rotating electrical machine includes a rotor shaft configured to couple to a rotor and prevent the angular displacement of the rotor shaft relative to the rotor; a fluid supply tube, located within the rotor shaft, configured to receive fluid at a near end; a fluid manifold, at an opposite end of the rotor shaft, in fluid communication with the fluid supply tube; and a rotor that includes a plurality of plates, having abutting radial sides, shaped, at an inner diameter, or between the inner diameter and an outer diameter, to form one or more fluid passages extending along an axis of shaft rotation and fluidly communicating with the fluid manifold.

Description

8887-3351-2 (4.529) ROTOR ASSEMBLY COOLING SYSTEM TECHNICAL FIELD [0001]^ The present application relates to rotating electrical machines and, more particularly, to rotor assemblies included in the rotating electrical machines. BACKGROUND [0002]^ Rotating electrical machines are increasingly used in different applications, such as for propelling passenger vehicles. As the use of rotating electrical machines proliferates, increasing the efficiency of the rotating electrical machines becomes more desirable. One way to improve the efficiency of the rotating electrical machine is to more effectively cool its components. It would be helpful to better cool rotating electrical machines using fluid flow. SUMMARY [0003]^ In one implementation, a rotor assembly for a rotating electrical machine includes a rotor shaft configured to couple to a rotor and prevent the angular displacement of the rotor shaft relative to the rotor; a fluid supply tube, located within the rotor shaft, configured to receive fluid at a near end; a fluid manifold, at an opposite end of the rotor shaft, in fluid communication with the fluid supply tube; and a rotor that includes a plurality of plates, having abutting radial sides, shaped at an inner diameter, or between the inner diameter and an outer diameter, to form one or more fluid passages extending along an axis of shaft rotation and fluidly communicating with the fluid manifold. [0004]^ In another implementation, a rotor assembly for a rotating electrical machine includes a rotor shaft, having an outer surface and a cavity with a radially-inwardly-facing surface, configured to couple to a rotor and prevent the angular displacement of the rotor shaft relative to the rotor; a fluid 8887-3351-2 (4.529) supply tube, located within the cavity, configured to receive fluid at a near end of the rotor shaft; a fluid manifold, at a distal end of the rotor shaft, in fluid communication with the fluid supply tube and the cavity; and a groove, formed in the radially inwardly-facing surface of the cavity, in fluid communication with fluid manifold and at least partially forming a fluid passage that extends toward the near end of the rotor shaft. [0005]^ In yet another implementation, a rotor assembly for a rotating electrical machine includes a rotor shaft, formed as a unitary structure, to couple to a rotor and prevent the angular displacement of the rotor shaft relative to the rotor; a fluid supply tube, located within the rotor shaft, configured to receive fluid at a near end; a fluid manifold, at a distal end of the rotor shaft, in fluid communication with the fluid supply tube; and a rotor, including a plurality of plates that are angularly displaced relative to each other an axis of shaft rotation, having abutting radial sides, shaped at an inner diameter, or between the inner diameter and an outer diameter, to form one or more fluid passages as a result of angular displacement, that extend along the axis of shaft rotation and fluidly communicate with the fluid manifold. BRIEF DESCRIPTION OF THE DRAWINGS [0006]^ Figure 1 is a cross-sectional view depicting an implementation of a rotor assembly; [0007]^ Figure 2 is another cross-sectional view depicting an implementation of a rotor assembly; ^ Figure 3 is a cross-sectional view depicting another implementation of a rotor assembly; [0009]^ Figure 4 is a cross-sectional view depicting another implementation of a rotor assembly; [0010]^ Figure 5 is an exploded view depicting an implementation of a of a rotor assembly; [0011]^ Figures 6a-6d are profile views depicting implementations of portions of a rotor assembly. 8887-3351-2 (4.529) DETAILED DESCRIPTION [0012]^ A rotating electrical machine, sometime referred to as an electric motor, includes a stator having stator windings and a rotor that is angularly displaced relative to the stator in response to flow of electrical current through stator windings. Rotating electrical machines can be implemented with stators and rotors having a variety of different designs. For instance, a rotor assembly can include an elongated shaft carrying an axially-extending stack of metal plates coupled together forming the rotor. The rotor assembly can be received within the stator in an assembled rotating electrical machine. As part cooling the rotating electrical machine, the rotor assembly can include a cooling system with fluid passages that receives fluid and directs the flow of fluid within the rotor assembly to reduce the temperature of the rotor assembly and the rotating electrical machine. In the past, rotor shafts have used other features to cool the rotating electrical machine. For example, the rotor shaft may aluminum heat sinks. However, the aluminum heat sinks and the process for combining them with the rotor shaft can be time consuming. [0013]^ In the proposed rotor assembly, a rotor shaft can include a hollow cavity open at one end of the shaft. A fluid supply tube can be positioned within the cavity, supported by an inlet bushing at one end of the rotor shaft. The fluid tube can fluidly couple with an opposite end of the rotor shaft within the cavity where a fluid manifold can receive the fluid supply tube and direct the fluid radially-outwardly toward an outer surface of the rotor shaft and the plates included in the rotor assembly. The fluid can then flow axially along the rotor shaft and return toward the inlet bushing. ^ The fluid passages can extend axially through the rotor assembly in different locations. For instance, in one implementation, a fluid passage can exist in the form of grooves formed in a radially-inwardly facing surface of the cavity. The grooves can be shaped to facilitate axial fluid flow along the rotor shaft. Another fluid passage can be formed by an outlet orifice in the rotor shaft the cavity and the outer surface of the rotor shaft. Fluid can leave the 8887-3351-2 (4.529) fluid manifold through the orifice and flow axially parallel to the axis of shaft rotation (x) between the outer surface of the rotor shaft and an inner diameter of the metal plates. The fluid can re-enter the cavity at an inlet orifice permitting fluid flow from the outer surface of the rotor shaft into the cavity. It should be that implementations of rotor assemblies having a plurality of different fluid passages are possible. Fluid passages can also be formed, within the rotor plates, extending axially parallel to the axis of shaft rotation (x). Fluid can exit the fluid manifold and flow to a plate manifold formed by an axial stack- up of connected metal plates. Fluid passages can exist at the inner diameter of plates and/or be formed within the plates between the inner diameter and an outer diameter of the plates. The axially stacked and coupled plates, when assembled as part of the rotor assembly, can collectively define the fluid passage(s). In some implementations, the rotor shaft can have a reduced diameter section such that an outer diameter of the shaft is reduced along some length of the rotor shaft to form at least a portion of the fluid passage. [0015]^ Turning to Figures 1-2, a rotor assembly 10a, used with a rotating electrical machine, is shown having a cooling system 12a comprising one or more fluid passages 14 within the rotor assembly 10. The rotor assembly 10 includes a rotor shaft 16 having a cavity 18, a fluid supply tube 20a received within the 18, an inlet bushing 22 received by the cavity 18 at a near end 24 of the rotor shaft 16 supporting one end of the fluid supply tube 20, and an end cap 26 at an opposite end 28 of the rotor shaft 26, received within the cavity 18 supporting the fluid supply tube 20. [0016]^ The rotor shaft 16 can be formed in a variety of different ways from or more types of metals. For instance, the rotor shaft 16 can be forged steel. In another implementation, the rotor shaft 16 can be formed from powdered metal that is heated to form the shaft 16. In this implementation, the rotor shaft 16 is hollow and the cavity 18 is open at each end of the shaft 16. The fluid supply tube 20 can be inserted into the cavity 18 at the near end 24 such that the 20 extends substantially the length of the rotor shaft to the opposite end 26 of the shaft 16. The fluid supply tube 20 can receive fluid at the near end 24 of 8887-3351-2 (4.529) the rotor shaft 16 and communicate the fluid to the opposite end 26. The fluid can be supplied from an internal combustion engine or a dedicated source that passes the fluid through a heat exchanger (not shown) before providing the fluid to the fluid supply tube 20. The fluid can be engine oil used by an internal engine or some other petroleum- or synthetic-based lubricant that is capable of withstanding the temperatures at which the rotating electrical machine operates. It is possible to used water ethylene glycol (WEG) as well. In this implementation, the rotor assembly 10 includes an end cap 28 received at the opposite end 26 of the rotor shaft 16 and at least partially within the cavity The end cap 28 can be press fit into the rotor shaft 16 and/or mechanically coupled to the shaft 16 to prevent the angular displacement of the end cap 28 relative to the shaft 16. The end cap 28 can have a flange 30 with a shoulder that axially locates the end cap 28 along the rotor shaft 16 within the cavity 18. [0017]^ A fluid manifold 32 and fluid supply tube receiver 34 can be formed the end cap 28 and positioned within the cavity 18. The fluid supply tube 20 can be received by the fluid supply tube receiver 34 to radially locate and support the fluid supply tube 20 within the cavity 18 relative to the axis of shaft rotation (x). The fluid supply tube receiver 34 can form a portion of the fluid manifold 32 to receive fluid from the fluid supply tube 20 and communicate the fluid to one or fluid passages 14. The fluid manifold 32 can include one or more orifices 36 that are sized to control a flow rate of fluid to the fluid passage(s) 14. In this embodiment, the orifices 36 include a plurality of radially-extending bores between the fluid supply tube receiver 34 and an annular fluid channel 38 formed on an outer surface of the end cap 28. The annular fluid channel 38 can axially aligned along the rotor shaft 16 to be at least somewhat radially outward from apertures 40 in the shaft 16 that permit the fluid to move radially- outwardly relative to the axis of shaft rotation (x) and then axially along the rotor shaft 16 towards the near end 24 of the shaft 16. The rotor shaft 16 can be received within an inner diameter 42 of a stack up of rotor plates 44 that form the rotor 46. The details of the stack up of rotor plates and rotor will be discussed below in more detail. 8887-3351-2 (4.529) [0018]^ Fluid can exit the apertures 40 in the rotor shaft 16 and flow within a fluid passage 14 defined between an outer surface 48 of the rotor shaft 16 and the inner diameter 42 of the plates 44 or the rotor 46. In some implementations, the rotor shaft 16 can have a reduced outer diameter 50 concentric with at least a portion of the axial length of the fluid supply tube 20. The amount of diameter reduction can be selected based on the desired size of the fluid passage 14 and/or the flow rate of fluid through the fluid passage 14. Additional apertures 40 can be formed in the rotor shaft 16 at the near end 24 of the rotor shaft 16 in between the outer surface 48 of the shaft 16 and the cavity 18 to return the fluid to the heat exchanger. [0019]^ Another fluid passage 14 can be formed in a surface 52 of the cavity 18 within the rotor shaft 16. The fluid passage 14 can receive fluid from the annular fluid channel 38 having a first diameter wall 54 that forms a fluid-tight fit with the cavity 18 of the rotor shaft 16 preventing the escape of fluid from the channel 38 and a second diameter wall 56, smaller than the first wall 54, permitting the flow of fluid into the cavity 18. The surface 52 can include a helical groove 58 that is shaped to urge fluid toward the near end 24 of the rotor shaft 16. The rotation of the rotor assembly 10 during operation, combined with the change in diameter from the inlet to the outlet, can create a pumping action assisting the flow of fluid toward the near end 24. [0020]^ The inlet bushing 22 can be positioned within the cavity 18 at the near end 24 of the rotor shaft 16. The inlet bushing 22 can include a fluid supply tube receiver 60 to radially position the fluid supply tube 20 within the cavity 18. The fluid supply tube receiver 60 in the inlet bushing 22 can include an inner diameter 62 that can communicate fluid from the heat exchanger to the end cap 28. In addition, the inlet bushing 22 can include axially-extending fluid return passages 64. The return passages 64 can extend from one radial surface 66 of the inlet bushing 22 to another radial surface 66 to communicate fluid from the cavity 18 to the heat exchanger. 8887-3351-2 (4.529) [0021]^ Figure 3 depicts another implementation of a rotor assembly 10b with a cooling system 12b. The rotor assembly 10b can be formed as a unitary structure integrally including a fluid supply tube 20b but eliminating inclusion of an inlet bushing and a separate fluid supply tube received within a cavity. rotor shaft 16 can include the fluid supply tube 20b formed within the rotor shaft 16 extending from a near end 24 to an opposite end 26. The near end 24 of the cavity 18 can be in fluid communication with a fluid source providing fluid that has passed through a heat exchanger. The opposite end 26 of the rotor shaft 16 can include an integrally formed fluid manifold 32 that is bound at the end 26 of the shaft 16 by the end cap 28 having an output shaft 70. The fluid manifold 32 can include one or more radially-extending orifices 36 formed between the cavity 18 and the outer surface 48 of the shaft 16. The orifices 36 can flow fluid from the fluid manifold 32 to the fluid passages 14 formed between the inner diameter 42 of the plates 42 and an outer diameter 68 of the plates 42. 40 can be formed at the near end 24 of the rotor shaft 16 between the outer surface 48 of the shaft 16 and the fluid supply tube 20b to permit the flow of fluid from the fluid passage 14 to the heat exchanger. Figure 4 depicts yet another implementation of the rotor assembly 10c. The rotor assembly 10c shown in Figure 4 is substantially similar to the implementation shown and described respect to Figure 3. However, the rotor shaft 16 here is a unitary structure such the output shaft 70 can be integrally formed with the rotor shaft 16 at its opposite end 26. [0022]^ Figure 5 depicts a portion of the rotor assembly 10 including a stack-up of rotor plates 44 to be bonded together and extending axially forming rotor 46. The rotor 46 exists in the rotating electrical machine as a unitary structure. However, the rotor 46 can be formed from a plurality of individual metal plates 44 each having an inner diameter shape 72 and, optionally, orifices 74 in between the inner diameter 42 and outer diameter 68 of the plate 44 that, when axially stacked or combined with other plates 44, can form one or more passages 14 within the rotor 46. The rotor 46 can use a plurality of individual plates 44 some of which have one profile while others have different profiles. The rotor 46, and its use of plates 44 having different profiles, can form 8887-3351-2 (4.529) fluid channels 14 and at least part of a fluid manifold. The individual plates 44 shown collectively in Figure 5 forming part of the rotor 46 include first profile plates 44a, second profile plates 44b, third profile plates 44c, and fourth profile plates 44d as shown in Figure 6. The first profile plates 44a can include a of orifices 74 formed near, and uniformly spaced from, an inner diameter 42 of the plate 44. The second profile plate 44b can include a plurality of radially extending slots 76 intersecting the inner diameter 42 of the plate 44b. And the third profile plate 44c can include a solid surface between an inner diameter 42 of the plate 44c and an outer diameter 68 of the plate 44c. A fourth plate 44d can include orifices 74 that have a variable distance from the inner diameter 42. [0023]^ The identity of the plate 44 chosen along the axial length of the rotor 46 can create and define the fluid passages 14. For example, at least one third profile plate 44c can be positioned at the opposite end 26 of the rotor 46. inner diameter 42 of the plate 44c can closely conform to the outer surface 48 of the rotor shaft 16 to prevent escape of fluid. Adjacent to the third profile plate 44c, one or more second profile plates 44b can be positioned such that radial faces of the plates 44 bond to each other. The slots 76 in the second profile plates 44b can permit fluid to flow along the outer surface 48 of the rotor shaft 16 the slots 76 toward the near end 24 of the shaft 16. First profile plates 44a can be axially positioned next to second profile plates 44b such that the orifices 74 in the first profile plates 44a are at an angular position about the axis of shaft rotation (x) that aligns with the slots 76 of the second profile plates 44b. First profile plates 44a can extend along the axis of shaft rotation (x) to the near 24 where a plate combination of second and first profile plates 44a, 44b can terminate the fluid passages 44 at the near end 24 of the rotor 46 and direct fluid toward the heat exchanger. In one implementation, sixteen orifices can be formed in each first profile plate 44a, each having a 2.0mm diameter. Some implementations can angularly rotate adjacent first profile plates 44a relative to other to create a helically-shaped fluid passage within the rotor 46 such that the rotational movement of the rotor 46 during operation can facilitate the flow of fluid from the opposite end 26 of the rotor 46 to the near end 24 of the 8887-3351-2 (4.529) rotor 46. In one implementation, first profile plates 44a can be angularly displaced relative to adjacent first profile plates 44a by 1.5° about the axis of shaft rotation (x) to create the helically-shaped fluid passages. [0024]^ It is to be understood that the foregoing is a description of one or more embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims. [0025]^ As used in this specification and claims, the terms "e.g.," “for example,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation. ^

Claims

8887-3351-2 (4.529) What is claimed is: 1. A rotor assembly for a rotating electrical machine, comprising: a rotor shaft configured to couple to a rotor and prevent the angular displacement of the rotor shaft relative to the rotor; a fluid supply tube, located within the rotor shaft, configured to receive fluid at a near end; a fluid manifold, at an opposite end of the rotor shaft, in fluid communication with the fluid supply tube; and a rotor that includes a plurality of plates having abutting radial sides, shaped at an inner diameter, or between the inner diameter and an outer diameter, to form one or more fluid passages extending along an axis of shaft rotation and fluidly communicating with the fluid manifold. 2. The rotor assembly recited in claim 1, wherein the rotor shaft includes an end cap that at least partially forms the fluid manifold and is coupled to the distal end of the rotor shaft. 3. The rotor assembly recited in claim 1, wherein the rotor shaft includes a cavity having an inner surface facing the axis of shaft rotation and one or more fluid passages formed in the inner surface. 4. The rotor assembly recited in claim 3, wherein the one or more fluid passages are helically-shaped. 5. The rotor assembly recited in claim 1, further comprising an inlet bushing received within a cavity of the rotor shaft. 6. The rotor assembly recited in claim 5, wherein the inlet bushing includes a fluid passage extending from one radial side of the bushing to another radial side of the bushing, 7. The rotor assembly recited in claim 1, wherein the fluid manifold is formed in the distal end of the rotor shaft and a solid output shaft is received by the distal end of the rotor shaft. 8887-3351-2 (4.529) 8. The rotor assembly recited in claim 1, wherein the fluid manifold includes a metering orifice between the fluid supply tube and the one or more fluid passages. 9. The rotor assembly recited in claim 1, further comprising one or more fluid passages formed in a cavity of the rotor shaft. 10. The rotor assembly recited in claim 1, further comprising one or more fluid passages formed between an inner diameter of the rotor and an outer surface of the rotor shaft. 11. The rotor assembly recited in claim 10, wherein the outer surface of the rotor shaft has a reduced outer diameter section that at least partially forms the one or more fluid passages. 12. The rotor assembly recited in claim 1, wherein the rotor shaft is formed as a single unitary structure. 13. The rotor assembly recited in claim 1, wherein the fluid supply tube is a separate component from the rotor shaft. 14. A rotor assembly for a rotating electrical machine, comprising: a rotor shaft, having an outer surface and a cavity with a radially- inwardly-facing surface, configured to couple to a rotor and prevent the angular displacement of the rotor shaft relative to the rotor; a fluid supply tube, located within the cavity, configured to receive fluid at a near end of the rotor shaft; a fluid manifold, at a distal end of the rotor shaft, in fluid communication with the fluid supply tube and the cavity; and a groove, formed in the radially inwardly-facing surface of the cavity, in fluid communication with the fluid manifold and at least partially forming a fluid passage that extends toward the near end of the rotor shaft. 8887-3351-2 (4.529) 15. The rotor assembly recited in claim 14, wherein the outer surface of the rotor shaft has a reduced outer diameter section that at least partially forms the fluid passage. 16. The rotor assembly recited in claim 14, wherein the rotor shaft is formed as a single unitary structure. 17. The rotor assembly recited in claim 14, wherein the groove is helically shaped. 18. A rotor assembly for a rotating electrical machine, comprising: a rotor shaft, formed as a unitary structure, configured to couple to a rotor and prevent the angular displacement of the rotor shaft relative to the rotor; a fluid supply tube, located within the rotor shaft, configured to receive fluid at a near end; a fluid manifold, at a distal end of the rotor shaft, in fluid communication with the fluid supply tube; a rotor, including a plurality of plates that are angularly displaced relative to each other around an axis of shaft rotation, having abutting radial sides, shaped at an inner diameter, or between the inner diameter and an outer diameter, to form one or more fluid passages as a result of angular displacement, that extend along the axis of shaft rotation and fluidly communicate with the fluid manifold. 19. The rotor assembly recited in claim 18, wherein the plurality of plates has apertures between an inner diameter of the plates and an outer diameter of the plates. 20. The rotor assembly recited in claim 18, wherein the plurality of plates has slots that intersect an inner diameter.^