Cooling assembly for an electric machine

Abstract

A cooling assembly (36) for an electric machine (10) is disclosed. The cooling assembly (36) can include a generally cylindrical cooling jacket (40) for receiving a shaft (14), a rotor (18), and a stator (20). Further, the cooling jacket (40) can be disposed in an electric machine housing (12). Additionally, the cooling assembly (36) can include at least two first passages (60) in the cooling jacket (40) for circulating a first coolant and at least one second passage (62) in the cooling jacket (40) for circulating a second coolant, the second passage (62) being disposed between the at least two first passages (60). Further, the cooling assembly (36) can include a third passage (72) on an exterior of the electric machine housing (12), the third passage (72) extending through the housing (12) to fluidly connect the at least two first passages (60) and bypass the second passage (62).

Description

Technical Field

[0001] This disclosure generally relates to a cooling assembly for an electric motor, and more specifically to a cooling jacket having multiple coolants circulating therein. Background Technology

[0002] Electric motors are frequently used in manufacturing, mining, construction, transportation, and other work sectors. Motors, such as electric motors and generators, can generate mechanical power in response to an electrical input, or generate electrical power in response to a mechanical input. An electric motor (whether the device is used as a motor, generator, alternator, rotary converter, etc.) typically comprises a stationary (i.e., non-rotating) stator, a rotor rotating within the stator, and a housing. The stator generally comprises a core of ferromagnetic material and windings consisting of coils of insulated wire or conductor wound around pole plates. The rotor may also comprise a core of ferromagnetic material. While the construction of the core, windings, and other physical aspects of conventional electric motors is generally related, it will not be discussed further herein, as those skilled in the art will be familiar with the construction of conventional electric motors.

[0003] Electric motors and generators generate significant amounts of heat, necessitating efficient cooling systems. For example, during the generation of mechanical and electrical power, magnetic, resistive, and mechanical losses within the motor cause heat to accumulate in the stator. It is preferable to dissipate this heat to prevent damage, malfunction, and / or failure of the machine, and to improve its efficiency. One limitation on the power output of an electric motor is its ability to cool the stator and dissipate this excess heat. However, with technological advancements, the power density of electric motors is constantly increasing, and such machines are becoming increasingly difficult to cool. Cooling stator housings or cooling jackets, positioned between the stator and the housing of the motor, provide an excellent means of cooling these machines. Therefore, electric motors and generators are typically equipped with cooling jackets, which have grooves or passages for circulating coolant between the cooling jacket and the machine housing. Specifically, circulating water, oil, or air through the cooling jacket helps dissipate excess heat from these motors and thus cools them. Common coolants used in this industry include water and ethylene glycol mixtures (WEG) and oil coolants, but these are generally not used together in the same cooling jacket.

[0004] An exemplary arrangement for dissipating heat from an electric motor is disclosed in Kubes' U.S. Patent Application No. 2016 / 0141921 (“'921 Publication”). Specifically, the '921 Publication discloses a heat exchanger disposed between the stator and the motor housing, the exchanger being a sleeve or jacket having adjacent helical coolant flow paths on or through the outer surface of the sleeve. This configuration allows for double-helical flow paths around the stator for two different coolants. However, apart from the disclosed adjacent double-helical flow paths, this prior art disclosure does not provide any alternative arrangements for multiple cooling paths.

[0005] The disclosed cooling components and methods for cooling motors are intended to overcome one or more of the aforementioned limitations and / or other problems of the prior art. Summary of the Invention

[0006] According to one aspect of this disclosure, an electric motor is disclosed. The disclosed electric motor may include a housing, a shaft, a rotor, and a stator. Furthermore, the electric motor may include a cooling assembly having a cooling jacket disposed within the housing. The cooling jacket may have an inner surface defining a generally cylindrical cavity for receiving the stator, and an outer surface having at least two generally annular first grooves for circulating a first coolant. Additionally, the outer surface may have at least one generally annular second groove for circulating a second coolant, the second groove being disposed between the at least two first grooves. Furthermore, the cooling assembly may include a passage on the outer surface of the housing and extending through the housing to fluidly connect the at least two first grooves and bypass the second groove.

[0007] According to another aspect of this disclosure, a cooling assembly for an electric motor is disclosed. The cooling assembly may include a generally cylindrical cooling jacket configured to receive a shaft, rotor, and stator; and the cooling jacket may be configured to be disposed within an electric motor housing. The cooling assembly may further include at least two first passages in a cooling jacket for circulating a first coolant and at least one second passage in a cooling jacket for circulating a second coolant, the second passage being disposed between the at least two first passages. Furthermore, the cooling assembly may include a third passage on the exterior of the electric motor housing, the third passage extending through the housing to fluidly connect the at least two first passages and bypass the second passages.

[0008] According to another aspect of this disclosure, a method for cooling an electric motor is disclosed. The disclosed method may include the step of providing a cooling jacket received within an electric motor housing and having at least two first coolant passages and at least one second coolant passage, the second coolant passage being disposed between the at least two first coolant passages. Additionally, the disclosed method may include the step of providing a third passage on the exterior of the electric motor housing, the third passage fluidly connecting the at least two first coolant passages and bypassing the second coolant passage. Furthermore, the disclosed method may include the steps of: circulating first coolant through the at least two first coolant passages and the third passage; and circulating second coolant through the second coolant passage.

[0009] These and other aspects and features of this disclosure will be better understood when read in conjunction with the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view of an electric motor disclosed in accordance with an exemplary embodiment of this disclosure;

[0011] Figure 2 This is a perspective view of an exemplary embodiment of the cooling jacket according to the present disclosure;

[0012] Figure 3 Based on this disclosure Figure 1 An exploded perspective view of an exemplary motor, which includes a stator, a cooling jacket, and a housing;

[0013] Figure 4 Based on this disclosure Figure 1 An external view of an exemplary motor, with various passages for the cooling components inside the motor shown by dashed lines;

[0014] Figure 5 This is a cross-sectional view of a bypass component disposed on the outer surface of the motor housing according to the present disclosure; and

[0015] Figure 6 This is a flowchart of a method for cooling an electric motor according to this disclosure.

[0016] Although the following detailed description will give reference to certain illustrative embodiments, it should be understood that the drawings are not necessarily drawn to scale, and the disclosed embodiments are sometimes shown graphically and in partial views. Additionally, in some cases, details that are not essential for understanding the subject matter of the disclosure or that would obscure other details have been omitted. Therefore, it should be understood that this disclosure is not limited to the specific embodiments disclosed and described herein, but is limited to a reasonable reading of the entire disclosure and claims, and any equivalents thereof. Detailed Implementation

[0017] The cooling components and methods for cooling motors disclosed herein overcome certain limitations of the prior art. This disclosure is applicable to electric motors or generators performing operations associated with industries such as construction, agriculture, mining, manufacturing, transportation, or any other industry known in the art. Specific embodiments or features will now be described in detail, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding or similar reference numerals will be used throughout the drawings to denote the same or corresponding parts.

[0018] Figure 1 An exemplary motor 10 is shown. Motor 10 may be a generator or an electric motor, or selectively both. For example, motor 10 may be driven (e.g., by an engine) to generate electricity, as in hybrid vehicle applications or stationary power generation applications. Alternatively, motor 10 may be powered to generate mechanical rotation, as in engine starting applications or electric winch applications. It is also contemplated that motor 10 may function as a generator in some cases and as an electric motor in others, such as in electric drive system propulsion and braking applications.

[0019] Regardless of the application, among other things, the motor 10 may include a housing 12, a shaft 14 rotatably supported at opposite ends within the housing 12 by bearings 16, a rotor 18 operatively coupled to rotate with the shaft 14, and a stationary stator 20 annularly surrounding the rotor 18, etc. When the shaft 14 and rotor 18 are mechanically driven to rotate within the housing 12, the associated rotating magnetic field can generate a current within the stator 20. Similarly, when current flows through the stator 20, a magnetic field can be generated that causes the rotor 18 and shaft 14 to rotate. It is conceivable that the motor 10 may contain additional or different components, such as a control system, processor, power electronics, one or more sensors, energy storage devices, and / or other components known in the art. Such additional systems and components are outside the scope of this disclosure and therefore will not be discussed in more detail herein.

[0020] like Figure 1As shown, housing 12 may include a generally cylindrical shell 22 and one or more end caps. Shell 22 may substantially surround shaft 14, bearing 16, rotor 18, and stator 20. It is contemplated that in some embodiments, shell 22 may have two open ends, or it may have one open end and one closed end, depending on the application. Housing 12 may include a centrally located through-hole 30 that allows shaft 14 to extend through opposite ends of housing 12. It is further contemplated that shaft 14 may protrude through one or both ends of housing 12, depending on the application. Parts of housing 12 will be discussed with reference to the disclosed cooling function, but those skilled in the art will understand that housing 12 typically includes other aspects not described herein, depending on the application and requirements, for mounting, rigidity, electrical connection, etc. Housing 12 may be constructed of a material with relatively high thermal conductivity, such as metal. Advantageously, a metallic housing allows for efficient heat transfer.

[0021] The rotor 18 may be housed within the stator 20. The rotor 18 may be formed of a material typical of electric motors or generators and may be configured to rotate within the stator 20 to generate torque. The rotor 18, formed in a cylindrical shape, may have an open center for fixed connection to the shaft 14 and interact with a magnetic field within the motor 10 in response to rotation of the shaft 14. In one embodiment, the rotor 18 may include a stack of steel laminations and a plurality of radially projecting portions, also referred to as rotor teeth (not shown). As each projecting portion rotates to interact with the magnetic field of the stator 20, a corresponding current may be generated.

[0022] The stator 20 may be fixed to the housing 12 to generate a magnetic field that interacts with the radially projecting portions of the steel laminations. Similar to the rotor 18, the stator 20 may also include steel laminations formed in teeth (not shown). The teeth of the stator 20 may project radially inward toward the outwardly projecting rotor teeth of the rotor 18. In some applications, the stator 20 may also include coils or windings 34 of copper wire to form multiple poles. As the rotor 18 rotates to interact with the magnetic field of the stator 20, current can be sequentially generated from the windings 34 through each of the multiple poles.

[0023] For example Figure 1 As shown in the diagram, and described in detail below, the motor 10 may include a cooling assembly 36 for reducing heat in the motor 10 by directing at least two coolants throughout or near the primary heat-generating components of the motor 10. Among other things, the cooling assembly 36 includes a generally cylindrical cooling jacket 40 disposed between the stator 20 and the housing 12. Figure 2An exemplary generally hollow cooling jacket 40 is shown. The cooling jacket 40 may have an inner coaxial surface 42 and an outer coaxial surface 44, respectively. The inner surface 42 defines a generally cylindrical cavity 46. The body of the cooling jacket 40 may include a first axial end 48 and a second axial end 50. The first axial end 48 may be a first end, and the second axial end 50 may be a second end. The cavity 46 defined by the inner surface 42 of the cooling jacket 40 may extend from the first axial end 48 to the second axial end 50 and may open at the first axial end 48 and also at the second axial end 50. The cavity 46 may have a uniform diameter and may be configured to receive a stator 20. The figures show the cooling jacket 40 and housing 12 as generally cylindrical; however, it should be appreciated that various geometries of the cooling jacket and housing are conceivable within the scope of this disclosure. A mounting flange 52 may be located adjacent to the first axial end 48, and the flange 52 is configured to engage the cooling jacket 40 with the housing 12. For ease of connection, flange 52 may include bolt holes 54 formed therein, some of which are in Figure 2 As shown in the diagram. The connection between the cooling jacket 40 and the housing 12 may include any number of elements, such as flanges 52, bolts, lugs, or any other suitable means of fastening or connecting parts known in the art. For example, the connecting element may be a clamping shoulder, etc.

[0024] like Figure 2 As further shown, as described in detail below, the cooling jacket 40 may include a plurality of generally circumferential grooves formed in the outer surface 44 for allowing various coolants to circulate through pathways created between the grooves and the housing 12. The grooves may be positioned adjacent to each other along the length of the cooling jacket extending from the first axial end 48 to the second axial end 50. The grooves may include groups of axially advancing grooves, each group adapted to guide cooling fluid through adjacent grooves in an axially advancing direction. Alternatively, a single annular groove that does not allow coolant to advance axially may also be conceived and may interfere with the independent axially advancing grooves. As used herein, the term "axially advancing" should be understood to mean that the grooves are configured and / or oriented such that coolant flows in a direction of advancement relative to the longitudinal central axis of the cooling jacket 40. In other words, the axially advancing grooves will not be positioned at a consistent axial location around the longitudinal axis, but rather will be positioned such that they divert fluid toward or away from the first axial end 48 or the second axial end 50. Throughout this disclosure, the fluid path through which the first coolant circulates is interchangeably referred to as the first groove 60 or the first passage 60; and the fluid path through which the second coolant circulates is interchangeably referred to as the second groove 62 or the second passage 62. The first groove / passage 60 and the second groove / passage 62 in the outer surface 44 of the cooling jacket 40 may have any width and depth suitable for a particular application and depending on the desired number and sequence of grooves / passages 60, 62.

[0025] exist Figure 2 In an exemplary embodiment, for example, the cooling jacket 40 may include a plurality of generally annular first grooves 60 for circulating a first coolant. Although the first grooves 60 are shown as two sets of first grooves 60, each set advances and helically rotates twice around the cooling jacket 40 (see also...). Figure 4 However, any number of first grooves 60 and helical rotation around the cooling jacket 40 are contemplated in this disclosure. Additionally, the cooling jacket 40 may include generally annular second grooves 62 for circulating a second coolant. The second grooves 62 may be disposed between the first grooves 60, and although the second groove 62 is shown as a single groove, multiple second grooves 62 for circulating the second coolant and second grooves 62 that advance axially and rotate helically are contemplated herein. Furthermore, although... Figure 2 A sequence of first grooves 60, second grooves 62, and first grooves 60 is shown on the outer surface 44 from one end of the cooling jacket 40 to the other, but additional sequences of grooves 60, 62 are contemplated herein. For example, additional second grooves 62 may also be provided on the opposite side of the first grooves 60 adjacent to the ends 48, 50 of the cooling jacket 40. Alternatively, the sequence of grooves 60, 62 shown may be repeated multiple times along the length of the cooling jacket 40 on the outer surface 44. Many variations of the illustrated embodiments are possible without departing from the scope of this disclosure, depending on the specific application, machine size, and heat transfer requirements.

[0026] The circulation of coolant through the grooves or passages 60, 62 of the cooling jacket 40 results in multiple coolant contacts between the cooling jacket 40 and the housing 12, as well as between the cooling jacket and the housing, thereby removing heat and cooling the stator 20. As understood in the art, the cooling performance of the cooling assembly 36 can be optimized by the shape and length of the grooves 60, 62 in the cooling jacket 40 and the speed at which the coolant moves through them.

[0027] The cooling jacket 40 of this disclosure can be manufactured by a casting process. In the context of this disclosure, casting is to be understood as any manufacturing process that introduces molten material, such as metal or plastic, into a mold, allows it to solidify within the mold, and then ejects or breaks it to create a finished part. Casting is used to produce parts of complex shapes that would be difficult or uneconomical to produce by other methods, such as cutting from a solid material. Types of casting known in the art include sand casting, die casting, permanent mold casting, centrifugal casting, continuous casting, etc. Alternatively, as also known in the art, the cooling jacket 40 and / or its components can be machine-made. Optionally, and also contemplated herein, the cooling jacket 40 can be cast directly into the housing 12 of the motor 10. Whether by casting or machining, among other things, the outer surface 44 of the currently disclosed cooling jacket 40 includes features for guiding and circulating various coolants, namely a first groove or passage 60 and a second groove or passage 62.

[0028] Go to Figure 3 , showed Figure 1 An exploded or disassembled view of certain components of the motor 10, including the housing 12, cooling jacket 40, and stator 20. (See attached image.) Figure 1 and 3 As shown, the cooling jacket 40 is received in the housing 12, and the stator 20 is received in the cooling jacket 40, both coaxially. Contact between the outer surface 44 of the cooling jacket 40 (in which it has the aforementioned grooves 60, 62) and the shell 22 of the housing 12 establishes a first passage 60 and a second passage 62, as well as corresponding first and second coolant flow paths for circulating both coolants through the cooling jacket 40. The cooling jacket 40 is sealed within the housing 12 in a manner designed to prevent the first and second coolants from escaping their respective passages 60, 62. Proper orientation / alignment of the supply and discharge ports (described in detail below) with the coolant passages 60, 62 can be achieved by appropriately orienting the cooling jacket 40 and the housing 12 during the guidance of the cooling jacket 40 into the housing 12. As discussed above, the cooling jacket 40 can be bolted to the housing 12 via flange 52 or attached by any other suitable means. The cooling jacket 40 can also be coupled to the housing 12 via a press fit.

[0029] In addition to the surface-to-surface contact between the outer surface 44 of the cooling jacket 40 and the shell 22 of the housing 12, one or more O-rings 64 may be used to add further contact between the components and to form an additional seal between the cooling jacket 40 and the housing 12 (see [link to documentation]). Figure 1 and 5 The O-ring 64 can be positioned in an additional groove on the outer surface 44 of the cooling jacket 40. As described above and further detailed below, the configuration of this disclosure allows multiple coolants to flow axially through the cooling jacket 40 simultaneously. Since different coolants are supplied from independent sources and are responsible for different cooling functions, the different coolants should be isolated and not allowed to mix within the cooling jacket 40. In addition to the surface-to-surface seal between the cooling jacket 40 and the housing 12, the O-ring 64 provides an additional seal between the first coolant passage 60 and the second coolant passage 62. In this way, cross-contamination of different coolant fluids is prevented. Specifically, although there is a surface-to-surface seal between the cooling jacket 40 and the housing 12, the O-ring 64 prevents any further movement of coolant if any coolant fluid escapes from its respective passage 60, 62, and thus prevents coolant contamination in adjacent passages. Any number of O-rings 64 may be used between the cooling jacket 40 and the housing 12; and although the O-rings 64 are shown herein only as being disposed between the first passage 60 and the central second passage 62, the O-rings may also be disposed on opposite sides of the first passage 60, and between any additional coolant passages in the cooling jacket 40.

[0030] The stator 20 may be received within the cooling jacket 40 such that the stator 20 is in thermal contact with the inner surface 42 of the cooling jacket 40. It may be desirable to place the stator 20 within the cooling jacket 40 before placing it within the outer housing 12. In this case, the cooling jacket 40 may expand by heating, the stator 20 may be placed therein, and then the cooling jacket 40 may allow cooling and thus contract around the stator 20. The stator 20 may include a first axial end and a second axial end and may be retained within the cooling jacket 40 such that the first and second axial ends of the stator 20 are substantially aligned with the first axial end 48 and the second axial end 50 of the cooling jacket 40. Furthermore, as is generally understood in the art and therefore not described in detail herein, a suitable generator rotor 18 or motor rotor 18 may be positioned within the stator 20 and connected thereto by an input coupling or an output coupling, respectively.

[0031] Figure 4 An external view of the assembled motor 10 and housing 12 is shown. The cooling jacket 40, concealed within the housing 12, is not specifically mentioned; however, a first coolant passage 60 and a second coolant passage 62 of the cooling jacket 40 are depicted in the shade below the shell 22 of the housing 12 using dashed lines. In this exemplary embodiment, the ends 66 of the two sets of first coolant passages 60 are depicted, the passages 60 advancing axially and turning twice around the cooling jacket 40 and the stator 20 (also not visible in this view). Alternatively, this embodiment includes only a single second passage 62, disposed between the first coolant passages 60. As noted above, although not depicted, any number and any axially positioned additional first and second coolant passages 60 and 62 on the cooling jacket 40 are within the scope of this disclosure.

[0032] The exterior of housing 12 may be adapted to have a port 68 extending through housing 12 and in fluid communication with the first passage 60, thereby facilitating the supply and / or discharge of the first coolant from the first passage 60. Similarly, although... Figure 4 Not shown, but housing 12 may also include an additional port for supplying / discharging a second coolant through the second passage 62. It should be understood that in use, the first and second coolants may be pressurized by a pump (not shown) and directed into one of the ports 68 for circulation through the cooling jacket 40. The motor housing 12 and passages 60, 62 may be adapted to have any number of ports 68, whether inlet or outlet, depending on the specific application and requirements. In the currently depicted embodiment, the first coolant may enter through one port 68 and be directed along the first passage 60 to another port 68, such ports serving as inlet and outlet ports, respectively.

[0033] It should be understood that the disclosed configuration allows for reversal of the coolant flow direction (if desired). In other contemplated embodiments, the coolant passages are adapted to have additional inlet and outlet ports to allow coolant to circulate simultaneously in multiple directions. When passages 60, 62 are filled with a first or second coolant from, for example, a first coolant reservoir and a second coolant reservoir or other supply location, one port 68 can be used to purge air, while the other port 68 receives and supplies coolant. As is generally understood in the art, port 68 allows for the resupply of coolant from one port to another and a continuous fluid flow path through the cooling jacket 40. As is generally practiced in the art, coolant leaving motor 10 can be directed to a heat exchanger, where the absorbed heat can be transferred to the atmosphere before the coolant returns to motor 10. Additionally, as is also well known in the art, housing 12 may also be adapted to have vents (not shown) for purging air, oil, etc., from housing 12 of motor 10.

[0034] Further reference is made to the cooling assembly 36 of this disclosure, Figure 4 and 5 A bypass component 70 disposed on the housing 12 of the motor 10 is also shown. This bypass component 70 may include a third passage 72 that extends through the housing 12 to fluidly connect the two sets of first passages 60 by “skipping” the second passage 62. Figure 4 The exterior of the bypass component 70 on the surface of the motor housing 12 is shown, with the third passage 72 shown in shaded areas using dashed lines. Alternatively, Figure 5 A cross-sectional view of the bypass component 70 is shown, illustrating how the third passage 72 is aligned with and in fluid communication with the first passage 60. Specifically, the bypass component 70 is disposed on the motor housing 12 such that the third passage 72 is aligned with the end 66 of another separate group of first coolant passages 60. In this way, by connecting the group of first passages 60 and bypassing the second passage 62, the third passage 72 provides a first coolant flow path 74 around the second passage 62, allowing the first coolant flow to axially flow from one end of the cooling jacket 40 to the other, while the second coolant flows between the first coolant flow paths.

[0035] As shown, the bypass component 70 can be an elongated block structure, cast and integrally formed with the motor housing 12. Alternatively, a separately manufactured bypass component can be fastened to the outer surface of the housing 12. Such a bypass component can have the same material as the housing 12, or any other material known in the art. In the illustrated embodiment, the third passage 72 is machined into the bypass component 70. Specifically, as Figure 5As shown, the third passage 72 is created by drilling through the bypass component 70 at three locations and ultimately creating three contiguous passages through the housing 12 at two additional locations, two of which intersect with the group of first passages 60 and create fluid communication between the group of first passages. This configuration requires precise alignment of the bypass component 70 with the first passages 60 such that the third passage 72 extends through the housing 12 to fluidly connect the group of first passages 60. Also as shown, a plug 76 or any suitable device may be incorporated into the bypass component 70 to block or seal the exposed end of the machined third passage 72, thereby providing a continuous first coolant flow path 74 between the first passages 60.

[0036] As mentioned, the bypass component 70 can be attached to the housing surface using any suitable fastening device, rather than being integral with the housing 12. For example, the bypass component 70 can be a separate cast component similar in shape to that depicted and having a third passage 72 therein. Such a bypass component and the third passage can be aligned with a hole extending through the motor housing 12 to intersect with the first passage 60, and then fastened to the housing 12. This configuration will also provide a continuous coolant flow path 74 between the first passages 60 and around the second passage 62. Any number of configurations that can achieve this function are contemplated herein. For example, another alternative embodiment may include attaching a pipe or conduit to the outer surface of the housing 12 to provide fluid communication between certain passages and around other passages. Such attachment of a pipe or conduit may include any suitable fastening device known in the art capable of providing a tight fluid seal between the passages.

[0037] In cases involving such independent bypass components, it is also contemplated herein that existing motors can be retrofitted with the elements of this disclosure. Specifically, in cases where existing machines include cooling jackets with multiple axially advancing coolant passages, such machines can be retrofitted with the disclosed bypass components to allow multiple coolant flow paths through the cooling jacket without coolant cross-contamination. Therefore, kits for retrofitting existing motors with the elements of this disclosure are further contemplated herein. Specifically, such kits may include a bypass component 70 and any necessary fastening devices (including, but not limited to, additional tubes, bolts, flanges, brackets, straps, and clamps) for attaching the bypass component 70, such that it fluidly connects some passages while bypassing another. It should be understood that any such adaptation of an existing motor may further require the incorporation of additional ports and / or other components.

[0038] Furthermore, as mentioned above, the scope of this disclosure includes motors with cooling jackets having additional and alternative first and second passages and / or a series of first and second passages. In this regard, it is also contemplated that multiple bypass components can be used on the motor housing to fluidly connect passages of the same coolant. For example, if the illustrated cooling jacket 40 is adapted to have an additional second passage at the axial ends 48, 50 of the cooling jacket 40 opposite the first passage 60, one or more of the disclosed bypass components 70 can be used to fluidly connect the additional second passage to the central second passage 62. Depending on the specific cooling jacket design and heat transfer requirements, any number of bypass configurations between one or more similar coolant passages using bypass components are possible and contemplated in this disclosure.

[0039] Figure 6 A flowchart of a method for cooling motor 10 is shown. Figure 6 The methods and concepts disclosed are discussed in more detail in the following paragraphs to further illustrate them.

[0040] Industrial applicability

[0041] The disclosed cooling assembly 36 for motor 10 finds potential application in any electric motor or generator where a controlled and consistent dissipation of significant heat is desired. The disclosed cooling assembly 36 increases the cooling efficiency of motor 10 without substantially increasing its size or weight. The cooling assembly and method disclosed herein can be used in any environment, including for motors in moving vehicles or stationary applications. Suitable operating environments for motors with the disclosed cooling assembly may include mining, locomotives, agriculture, transportation, construction, etc. In such applications, as detailed below, the disclosed principles are applied to cooling the stator 20 of motor 10 using two separate coolant fluids in the same cooling jacket 40.

[0042] Turning Figure 6 A flowchart of a method 100 for cooling an electric motor 10 is shown. The disclosed method 100 begins at step 110 by providing a cooling jacket 40, which is received within the motor housing 12 and has at least two first coolant passages 60 and at least one second coolant passage 62 disposed between the at least two first coolant passages 60. (Refer to the above...) Figure 1-5 The cooling jacket 40 receives the stator 20 and rotor 18 of the motor 10. Furthermore, the cooling jacket 40, stator 20, and rotor 18 are all coaxially arranged within the motor housing 12. In this manner, the cooling jacket 40 is positioned between the thermal power generation stator 20 and the motor housing 12 with heat transfer capability.

[0043] The disclosed cooling jacket 40 uses two different coolants to dissipate heat from the stator 20, each coolant flowing through a separate coolant circuit or passage 60, 62. The first coolant circulating through the first passage 60 may be a mixture of water and ethylene glycol (and other components), also known as WEG coolant. This first WEG coolant is primarily used to cool the stator 20 by circulating around the cooling jacket 40, while also advancing axially through the cooling jacket 40, which directly contacts the stator 20 in a heat transfer manner. Continuous circulation of the first coolant through the cooling jacket 40 is further facilitated by resupplying and discharging the first coolant from a first coolant reservoir through inlet and outlet ports 68. The second coolant circulating through the second passage 62 may be an oil-based coolant, including any type of oil, transmission fluid, or lubricating fluid. This second coolant can be used to cool the internal components of the motor 10, including the coils or windings 34 of the stator 20. Similar to the first coolant, the second coolant may circulate around the cooling jacket 40, and although not shown, may also circulate axially through the cooling jacket 40. Additionally, as is commonly practiced in the art, the second oil coolant may be allowed to seep through a second passage 62 of the cooling jacket 40 and into the stator 20, thereby contacting and cooling the windings 34 of the stator 20. The second oil coolant may also be resupplied and / or discharged through a port on the housing, which is in fluid communication with the second passage 62.

[0044] As described above, the disclosed cooling jacket 40 can be designed to have any number of grooves corresponding to the first passage 60 and the second passage 62. The first passage 60 and the second passage 62 can be arranged alternately along the length axis of the cooling jacket 40. Furthermore, any number of groups of passages 60, 62 can be included. Figure 1 , 2 As shown in Figures 4 and 5, the cooling jacket 40 may include the following axially advancing passage sequence: a set of first passages 60 spiraling twice around the cooling jacket 40, a second passage 62 spiraling twice around the cooling jacket 40, and another set of first passages 60 spiraling twice around the cooling jacket 40. In this way, advantageously, the second coolant can circulate between the circulation passages 60 of the first coolant. Furthermore, the spiral of the first passages 60 (and potentially the second passages 62) can provide uniform distributed cooling along the length of the stator 20.

[0045] To allow the first coolant to circulate between the two sets of first passages 60 shown, a third passage 72 is provided that bypasses the intervening second passage 62. Therefore, the method 100 of cooling the motor 10 includes, as step 120, providing a third passage 72 on the exterior of the motor housing 12, the third passage 72 fluidly connecting at least two of the first coolant passages 60 and bypassing the second coolant passage 62. This third passage 72 may be part of a bypass component 70 integrally disposed on the exterior of the housing 12, or may instead be fastened to the housing 12. In either case, the third passage 72 provides fluid communication between at least two of the first passages 60 and around the second passage 62. As shown throughout the figures, this bypass configuration advantageously allows two alternating coolants to circulate axially along the length of the cooling jacket 40. Furthermore, depending on the groove or passage design of a particular cooling jacket and its heat transfer requirements, the motor may be adapted to have any number of bypass components 70 connecting similar coolant passages, including oil passages bypassing the WEG passage.

[0046] Steps 130 and 140 of the method 100 for cooling the motor 10 require circulating a first coolant through at least two first coolant passages 60 and a third passage 72, and circulating a second coolant through a second coolant passage 62, respectively. As described above, the first coolant may be a WEG coolant intended to cool the stator 20 primarily by heat transfer, while the second coolant may be an oil coolant intended to cool the windings 34 of the stator 20 primarily by heat transfer and direct contact. Cross-contamination of these two coolants circulating simultaneously through the cooling jacket 40 should be avoided. For this purpose, as... Figure 1 and 5 As shown, the disclosed cooling assembly 36 may further include an O-ring 64 radially disposed between the cooling jacket 40 and the housing 22, and axially disposed between the first passage 60 and the second passage 62. In this way, in addition to being sealed to each other via surface-to-surface contact between the outer surface 44 of the cooling jacket 40 and the housing 22 of the housing 12, the passages 60 and 62 are further sealed to each other by incorporating the O-ring 64. This configuration advantageously allows two independent coolants to circulate alternately axially throughout the cooling jacket 40 without mixing or contaminating either coolant. Although not shown, the O-ring 64 may be incorporated anywhere along the axial length of the cooling jacket 40, most notably between the alternating first passage 60 and second passage 62.

[0047] This disclosure also provides for retrofitting existing motors with bypass components 70. For example, depending on specific heat transfer requirements, an existing motor with a cooling jacket (in which there are grooves for circulating coolant fluid) may potentially be adapted to have one or more bypass components 70. In this regard, kits including bypass components 70, as well as any attachments necessary to adapt an existing motor to have bypass components 70, are also contemplated herein. Additional ports may be added if desired to allow continuous circulation of two different coolants along the length of the cooling jacket, and to change the number and sequence of potentially alternating coolant passages. Additionally, existing motors may be adapted to have entirely new cooling assemblies of this disclosure. For example, an existing conventional motor may be disassembled and subsequently adapted and reassembled with the cooling assembly of this disclosure, including the cooling jacket 40 and the bypass components 70. In these different ways, this disclosure provides the potential to upgrade existing motors.

[0048] By guiding two different coolants through adjacent coolant passages 60, 62 arranged along the longitudinal axis of the cooling jacket 40, the aforementioned cooling assembly 36 and method 100 can provide greater cooling efficiency for the motor 10. Specifically, the first WEG coolant for cooling the stator 20, together with the second oil coolant for cooling the windings 34, provides cooling for the components of the motor 10 that tend to generate the most heat. Any heat-induced stress or damage experienced by the components of a motor with a conventional cooling jacket can then be reduced.

[0049] All references to this disclosure or examples thereof are intended to refer to the specific examples discussed at the time and are not intended to imply any limitation on the scope of this disclosure in a more general sense. Furthermore, it will be apparent to those skilled in the art that various modifications and variations of the cooling components of this disclosure can be made without departing from the scope of this disclosure. Other embodiments will be apparent to those skilled in the art in consideration of the description and implementation of the embodiments disclosed herein. Specific arrangements for a given application will depend on size, heat transfer requirements, and possibly other factors. Therefore, this disclosure is intended to be illustrative only and to cover all alternatives, modifications, and variations falling within the spirit and scope of the appended claims.

Claims

1. A cooling assembly (36) for an electric motor (10), comprising: A generally cylindrical cooling jacket (40) is constructed to receive the shaft (14), rotor (18) and stator (20), and the cooling jacket (40) is configured to be disposed in the motor housing (12); A first coolant passage (60) and a second coolant passage (60) formed in the cooling jacket (40) for circulating the first coolant; A second coolant passage (62) formed in the cooling jacket (40) for circulating a second coolant, the second coolant passage (62) being disposed between the first coolant passage (60) and the second coolant passage (60); and A bypass passage (72) fluidly communicates between the first coolant passage and the second coolant passage, the bypass passage (72) including a portion extending through the housing (12) and simultaneously bypassing the second coolant passage (62), thereby preventing cross-contamination between the first coolant and the second coolant, the first coolant circulating sequentially through the first coolant passage, the bypass passage and the second coolant passage.

2. The cooling assembly (36) according to claim 1, wherein each of the first first coolant passage (60) and the second first coolant passage (60) is configured to circulate a first coolant based on water and ethylene glycol.

3. The cooling assembly (36) of claim 1, wherein the second coolant passage (62) is configured to circulate an oil-based second coolant.

4. The cooling assembly (36) according to claim 1, further comprising one or more O-rings (64) disposed on the cooling jacket (40) between the first coolant passage (60) and the second coolant passage (62).

5. The cooling assembly (36) according to claim 1, wherein the bypass passage (72) is part of a kit for retrofitting an existing motor (10).

6. The cooling assembly (36) of claim 1, wherein the bypass passage (72) includes a pipe configured for attachment to the exterior of the motor housing (12).

7. A method (100) for cooling an electric motor (10), comprising the following steps: A cooling jacket (40) is provided, the cooling jacket (40) being received in the motor housing (12) and having a first coolant passage (60), a second coolant passage (60), and a second coolant passage (62), the second coolant passage (62) being disposed between the first coolant passage (60) and the second coolant passage (60); A bypass passage (72) is provided, which is configured to be in fluid communication between the first coolant passage (60) and the second coolant passage, the bypass passage (72) including a portion extending through the housing and bypassing the second coolant passage (62), thereby preventing cross-contamination between the first coolant and the second coolant; The first coolant is circulated sequentially through the first first coolant passage (60), the bypass passage (72), and the second first coolant passage; and The second coolant is circulated through the second coolant passage (62).

8. The method (100) of claim 7, further comprising the step of providing one or more O-rings (64) between the first coolant passage (60) and the second coolant passage (62).

9. The method (100) according to claim 7, wherein the first coolant is a water and ethylene glycol-based coolant configured to cool the stator (20) of the motor (10).

10. The method (100) of claim 7, wherein the second coolant is an oil-based coolant configured to cool the stator windings (34) of the motor (10).

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