Electric machine with low profile holding assembly for holding stator core

Abstract

An electric machine (30) having a low profile retention assembly (46) for retaining a stator core (32) is disclosed. A first housing (36) accommodates the stator core (32). The first housing (36) has an axial end face (56) with a circumferentially extending shaped profile with axially inwardly projecting recessed portions (58) alternating with non-recessed portions (60). A portion of the stator core (32) extends axially from the recessed portion (58). A core retaining spring (62) is disposed circumferentially at the axial end face (56) of the first housing (36). The core retaining spring (62) is in direct contact with the portion of the stator core (32) extending axially from the recessed portion (58) of the first housing (36) and the shaped profile of the housing (36). The core retention spring (62) urges against the portion of the stator core (32) extending axially from the first housing (36) to apply one or more of an axial load and a radial load into the stator core (32).

Description

Background Art Technical Field

[0001] Embodiments of the present disclosure relate generally to electric machines, and more particularly, to low profile retention assemblies for providing one or more of axial and radial load retention of a stator core in an electric machine.

[0002] Discussion of the field

[0003] As electric machines such as generators and motors become more prevalent in transportation applications (e.g., vehicles and aerospace), compact size and weight savings of the components of these electric machines have become major design requirements. However, the compact size and weight savings design requirements must be considered in consideration of the different temperatures and / or environmental impact loads that these electric machines can withstand during operation, handling, and manufacturing of the electric machines. In order to handle transient conditions caused by the different temperatures and / or environmental impact loads, the stator core of the electric machine must maintain axial and radial forces entering therein to ensure proper operating function.

[0004] One approach that has been used to compensate for different temperatures and / or environmental impact loads involves placing 360° springs into slots in the housing that houses the stator core. To this extent, the springs push directly against the stator core to maintain an axial force in the core that can withstand the impact loads. However, electric machines with primary design requirements of compact size and weight savings typically do not have axial and radial space in the housing to accommodate springs that can maintain axial forces into the stator core. In particular, because these electric machines have such tight axial and radial space constraints, there is not enough mechanical or electrical clearance space to accommodate a spring in the housing that can push directly against the stator core to keep it in axial and / or radial compression to handle transient conditions caused by different temperatures and / or environmental impact loads.

[0005] Another consideration for motors is that motors are now often manufactured from new resin materials that also have derivative consequences with respect to temperature and / or environmentally impacted loads. For example, when higher power density motors are needed to meet overall system power and efficiency targets, high temperature grade insulation is required and new resin formulations need to be used. Many of these new resin materials need to be cured at very high temperatures, sometimes significantly above the maximum operating temperature. Therefore, the components of the motor (especially the core) must be able to accommodate thermal transient growth differences during handling and during operation. This is especially true for press-fit and shrink-fit part interfaces between components of the motor such as the stator core and the housing. If the interface between the stator core and the housing cannot accommodate the thermal transient growth differences that occur during handling and operation, the stator core may loosen from the housing, which can affect the performance of the motor. Summary of the invention

[0006] A simplified overview of the disclosed subject matter is presented below in order to provide a basic understanding of some aspects of the various embodiments described herein. This overview is not an extensive review of the various embodiments. It is not intended to exclusively identify the key features or essential features of the claimed subject matter set forth in the claims, nor is it intended to be used to help determine the scope of the claimed subject matter. Its sole purpose is to present some concepts of the disclosure in a simplified form for preface, with a more detailed description presented later.

[0007] Embodiments described herein provide solutions to challenges associated with smaller and lighter electric machines that lack axial and radial space to deploy springs in a housing containing a stator core to withstand varying temperature and / or environmental impact loads that may occur during operation, handling, and manufacturing of the electric machine. Embodiments provide solutions to the need for using a low-profile retention assembly for those smaller and lighter electric machines that have a stator core in a housing with tight radial and axial space constraints that can provide one or more of axial and radial load retention of the core during operation, handling, and manufacturing of the electric machine.

[0008] In one embodiment, instead of using the axial and radial spaces in the housing to contain the stator core, the axial face of the housing can be used to receive the spring. In this way, the spring can press or push against the core end rings that hold the stator core in the housing. The pressing or pushing of the spring against the core end rings applies a force (axial load) into the stator core. To this extent, the force can keep the stator core in axial compression.

[0009] In another embodiment, the spring may be pressed or pushed directly into the stator core itself to apply an axial load directly into the core, thereby bypassing the use of core end rings. For example, the stator core at the axial face of the housing may be shaped to have features corresponding to the shape and characteristics of the core end rings at that location, thereby eliminating the use of core end rings. In this way, the spring can be used to press or push directly into those features of the stator core that are shaped to correspond to the features of the core end rings, which will occupy the space mentioned in the previous embodiment. Pressing or pushing the spring into those features will apply an axial load to the stator core.

[0010] In yet another embodiment, a low profile retention assembly may be provided to apply one or more of a radial load and an axial load into the stator core. For example, the stator core and core end rings at the axial face of the housing may be configured to have angled surfaces (e.g., tapered surfaces) formed between these components. Depending on the angled surfaces, the application of the spring to the surface may generate a resultant force vector into the surface that may be resolved as a radial load, an axial load, or both. To this extent, a load may then be applied to the stator core to hold it in compression corresponding to the load.

[0011] In order to use the axial face of the housing to deploy the spring to promote the axial compression of the stator core, some embodiments can provide an axial face with a geometry that allows the core end ring to be placed protrudingly in such a tight axial and radial space near the housing and not completely recessed or nested in the housing. In one embodiment, the geometry at the axial face of the housing may include a shaped profile having a concave portion protruding axially inward from the axial end face of the housing, which is alternating with non-concave portions. The shaped profile may extend circumferentially around the edge or edge of the axial face. In one embodiment, in the case of a shaped profile of a concave portion protruding axially inward from the axial end face of the housing alternating with non-concave portions, a portion of the core end ring may extend axially from the axial end face of the housing. This allows the spring applied to the axial face of the housing to press against the core end ring during the occurrence of the impact load. The pressing of the spring against the core end ring causes a force (axial load) to be applied to the stator core, so that the main load path of the force to the core passes through the core end ring. In this way, the force applied to the stator core can keep the core in axial compression during load-influencing instances where the stator core has a tendency to translate, deflect, or separate relative to the housing. This axial compression can be a constant compression or a varying compression.

[0012] In one embodiment, the formed profile of the housing may include a scalloped profile having a plurality of spaced apart scalloped surfaces formed on an axial end face of the housing. In addition to the scalloped profile, certain embodiments may include providing an axial face of the housing with axially and radially extending core retaining spring features that enable the spring to be secured to the housing at the axial face so as to interact with the core end ring. In one embodiment, the core retaining spring features may be arranged between the scalloped surfaces to form an alternating pattern of scalloped surfaces and core retaining spring features. This allows the spring to be disposed at the axial face of the housing in such a manner that the spring can be secured and maintained at the axial face to engage with the core end ring during impact load instances. In this manner, the core end ring can apply an axial load to the stator core to keep it in axial compression during these impact load instances.

[0013] The core retaining spring feature may include a plurality of different retaining features. For example, in one embodiment, the core retaining spring feature may include an axially extending through hole complementary to receive the spring retaining hardware and a radially extending slot opposite the through hole. To this extent, the through hole and the spring retaining hardware and the radially extending slot may each secure a portion of the spring to the axial end face of the housing.

[0014] In another embodiment, the core retention spring feature may include a pair of opposing radially extending grooves and an axially extending lip feature disposed between the grooves. In this manner, the grooves may each receive a portion of the spring, while another portion of the spring may be seated under the lip feature. In this arrangement, the grooves inhibit axial and circumferential movement of the spring, and the lip feature inhibits radial movement of the spring.

[0015] In yet another embodiment, the core retaining spring feature may include a first axially extending through hole and a second axially extending through hole opposite the first through hole. The first through hole and the second through hole are both complementary to receive spring retaining hardware. In this manner, the first through hole and the second through hole and the corresponding spring retaining hardware can secure a portion of the spring to the axial end face of the housing to inhibit axial and circumferential movement.

[0016] The springs that can be used in the low profile retention assemblies of various embodiments can include core retention springs. In one embodiment, the core retention spring can include a wave spring. For example, the core retention spring can include a 360° wave spring. The 360° wave spring can be arranged to abut against a shaped profile (e.g., a scalloped profile) of an axial face of the housing, with portions of the spring secured to any of the aforementioned core retention spring features that can be used with the housing.

[0017] In another embodiment, the core retaining spring may include a plurality of spaced apart segmented wave springs disposed circumferentially around the axial end face of the housing. The use of a plurality of spaced apart segmented wave springs disposed circumferentially around the axial end face of the housing facilitates assembly in tight radial and axial spaces, and may also provide weight savings compared to a 360° wave spring. Each segmented wave spring may have a first protruding leg, a second protruding leg, and a movable portion between the first protruding leg and the second protruding leg. The first protruding leg and the second protruding leg of each segmented wave spring may be attached to a shaped profile (e.g., a scalloped profile) at the axial end face of the housing by any of the aforementioned core retaining spring features that may be used with the housing. For example, the segmented wave spring may include through holes in one or more of the protruding legs to cooperate with a core retaining spring feature using complementary through holes and spring retaining hardware to secure the spring to the axial end face of the housing. In another embodiment, the protruding leg may be inserted into a core retaining spring feature that includes a radially extending slot. Regardless of the specific core retention spring features used, in certain embodiments, the active portion of each segmented wave spring may be in direct contact with the core end ring with the protruding legs secured to the scalloped profile.

[0018] In addition to the weight savings, the use of circumferentially arranged segmented wave springs reduces the amount of external radial and axial material associated with the use of 360° wave springs. Nevertheless, the circumferentially arranged segmented wave springs still achieve the purpose of attaching the springs to the axial face of the housing in a manner that allows the segmented wave springs to interact with the core end rings during impact load instances. In this manner, in certain embodiments, the segmented wave springs enable the core end rings to apply axial loads to the stator core to keep it in axial compression during impact load instances.

[0019] In either spring embodiment, both the 360° wave spring and the plurality of segmented wave springs advance the low profile aspect of the retaining assembly described herein. That is, in certain embodiments, both springs can be applied to a shaped profile (e.g., a scalloped profile) at the axial end face of the housing so that a portion of the spring can interact with the core end ring during an impact load instance to apply an axial load that keeps the stator core in axial compression. In addition, both spring embodiments can perform this function in very tight axial and radial spaces. In this way, the wave spring and any spring hardware that can be used to secure the spring to the housing are not near active electrical components of the stator winding (i.e., coil) that may cause electrical problems. In addition, in these embodiments, the position of the spring allows significantly more spring deflection in the axial direction, which is beneficial in accommodating a wide range of differential motor part interface movement and growth that may occur during motor operation, handling, and manufacturing. Moreover, the spring not only maintains an acceptable spring force during initial installation, but also maintains an acceptable force during higher temperature operation when thermal mismatch between the housing, the core end ring, and the stator core may occur.

[0020] The low profile retention assembly of various embodiments may also include an outer housing to accommodate a housing containing a shaped profile (e.g., a scalloped profile) and a core retention spring feature disposed at an axial end face thereof. In one embodiment, the outer housing may extend over an inner housing containing the shaped and core retention spring features and a spring disposed at an axial end face thereof (i.e., a 360° spring or a segmented spring). In this manner, the outer housing traps the spring underneath it, thereby inhibiting outer radial movement of the spring. The use of the outer housing in conjunction with the shaped profile and core retention spring feature on the axial end face of the inner housing ensures that the low profile retention assembly of various embodiments inhibits any degree of freedom of movement of the spring in the circumferential, radial, and axial directions.

[0021] According to one embodiment of the present invention, a retaining assembly for retaining a stator core in a stator of an electric machine is provided. The retaining assembly comprises: a first housing for accommodating the stator core, the first housing having an axial end face, the axial end face having a circumferentially extending shaped profile, the profile having recessed portions protruding axially inwardly from the axial end face of the housing, the recessed portions alternating with non-recessed portions, wherein a portion of the stator core extends axially outwardly beyond the recessed portions from the shaped profile at the axial end face of the first housing; and a core retaining spring, the core retaining spring being circumferentially arranged at the axial end face of the first housing, the core retaining spring being in direct contact with the portion of the stator core extending axially outwardly from the shaped profile of the first housing and the shaped profile of the first housing, wherein the core retaining spring pushes against the portion of the stator core extending axially outwardly from the shaped profile of the first housing, thereby applying one or more of an axial load and a radial load to the stator core, the axial load and the radial load keeping the stator core in axial and / or radial compression.

[0022] According to another embodiment, a retaining assembly for retaining a stator core in a stator of an electric machine is provided. The retaining assembly includes: a core end ring, which is circumferentially arranged at an axial end of the stator core; an inner housing for accommodating the stator core and the core end ring, the inner housing having an axial end face, the axial end face having a circumferentially extending fan-shaped profile, wherein a portion of the core end ring axially extends out from the fan-shaped profile at the axial end face of the inner housing; and a core retaining spring, the core retaining spring including a plurality of segmented core retaining springs circumferentially arranged at the axial end face of the inner housing, each segmented core retaining spring being contained by the axial end face of the inner housing, To inhibit circumferential and radial movement of the core retaining spring, each segmented core retaining spring is in direct contact with the portion of the core end ring that extends axially from the fan-shaped profile of the inner shell, and each segmented core retaining spring is pushed against the core end ring to apply one or more of an axial load and a radial load to the stator core, wherein the axial load and / or the radial load applied to the stator core via the core end ring by all the segmented core retaining springs among the multiple segmented core retaining springs keeps the stator core in axial compression and / or radial compression.

[0023] According to a third embodiment, a motor is provided. The motor includes: a stator core having a plurality of axially oriented slots radially extending from a central axis of the stator core, wherein a plurality of stator winding coils are arranged in the slots; an inner housing for accommodating the stator core, the inner housing having an axial end face having a circumferentially extending sectoral profile, wherein a portion of the stator core axially extends out from the sectoral profile at the axial end face of the inner housing; a core retaining spring circumferentially arranged at the axial end face of the inner housing, the core retaining spring being axially outwardly from the sectoral profile of the inner housing with the stator core; The extended portion is in direct contact with the fan-shaped profile of the inner shell, wherein the core retaining spring is pushed against the portion of the stator core that extends axially from the fan-shaped profile of the inner shell, and the core retaining spring applies one or more of an axial load and a radial load to the stator core, and the axial load and radial load keep the stator core in axial and / or radial compression; and an outer shell for accommodating the inner shell, the outer shell extending above the inner shell and the core retaining spring, wherein the outer shell traps the core retaining spring thereunder, thereby inhibiting radial movement of the outer side of the core retaining spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0025] Figure 1 shows a cross-sectional view of a portion of a stator of an electric machine according to the prior art;

[0026] Figure 2 A schematic diagram showing a front view of a stator end according to an embodiment of the present invention;

[0027] Figure 3 A method for retaining a stator core in a stator housing according to an embodiment of the present invention is shown. Figure 2 A schematic diagram of a perspective view of a portion of a core end ring depicted in FIG.

[0028] Figure 4 A schematic diagram showing a perspective view of a core retention spring according to an embodiment of the present invention, which core retention spring may be part of a retention assembly for retaining a stator core in an electric machine;

[0029] Figure 5 The embodiment according to the present invention is shown Figure 2 A schematic diagram of a perspective view of a portion of a stator end depicted in FIG.

[0030] Fig. 6A and Figure 6B A detailed description of an embodiment according to the present invention is shown Figure 2Schematic diagram of a perspective cross-sectional view of a portion of an axial end face of an inner housing in a stator depicted in FIG, which may form part of a retaining assembly for retaining a stator core in an electric machine;

[0031] Figure 7 a schematic diagram showing a top view of a core retention spring secured to a core retention spring feature provided in an axial end face of an inner housing, which may form part of a retention assembly for retaining a stator core in an electric machine, according to an embodiment of the present invention;

[0032] Figure 8 a schematic diagram showing a perspective view of a portion of an axial end face of an inner housing according to an embodiment of the present invention, with further details of a retaining assembly for retaining a stator core in an electric machine;

[0033] Fig. 9 a schematic diagram showing a perspective cutaway view of a portion of a stator having an outer shell, which may form part of a retaining assembly for retaining a stator core in an electric machine, according to an embodiment of the present invention; and

[0034] Fig.10 A schematic diagram showing a perspective view of a portion of an axial end face of an inner housing according to an embodiment of the present invention, with a 360° spring disposed on a sector-shaped profile of the end face in contact with a core ring. DETAILED DESCRIPTION

[0035] Exemplary embodiments of the invention will be described more fully hereinafter with reference to the accompanying drawings, in which some but not all embodiments are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers may refer to like elements throughout.

[0036] The present disclosure relates generally to electric machines such as generators and motors, and more specifically to low profile retention assemblies for providing one or more of axial and radial load retention of a stator core in an electric machine, which have utility in applications where it is desirable to make the electric machine compact and lightweight. Transportation applications, which may include automotive, aerospace, and other modes of transportation, are non-limiting examples in which compact and lightweight electric machines may be deployed. In these applications, there is typically insufficient radial and axial space in the housing of the electric machine containing the stator core to provide a stator core retention device (such as, for example, a spring capable of facilitating axial and radial forces into the core) to enable it to withstand transient conditions caused by varying temperatures and / or environmentally influenced loads. The low profile stator core retention assemblies of various embodiments require less axial and radial space and are therefore suitable for compact and lightweight electric machines, and particularly electric machines having their stator cores in housings with tight axial and radial space constraints. As used herein, an electric motor with tight axial and radial space constraints refers to an electric motor having a compressed axial and radial envelope that is limited in its height and width to accommodate a stator core retention device (e.g., a spring) while meeting the minimum electrical clearance requirements between the copper coil windings of the stator core and the retention device to prevent electrical insulation reliability issues.

[0037] Although various embodiments are described for compact and lightweight electric machines having tight axial and radial space constraints, these embodiments may have applicability on other electric machines, such as larger electric machines that do not have tight axial and radial space constraints but still need to maintain a stator core in order to compensate for transient conditions that could affect the proper operation of the electric machine.

[0038] In the following discussion, reference will be made to a set of axes. These axes are based on a cylindrical coordinate system and points in an axial direction A, a radial direction R, and a circumferential direction C that extends around a longitudinal axis aligned with the axial direction A. For example, the axial direction A extends along a longitudinal axis of the stator (e.g., a central axis of the stator), the radial direction R extends transversely (e.g., vertically) away from the longitudinal axis, and the circumferential direction C extends around the longitudinal axis.

[0039] Now turning to the attached figure, Figure 1 A cross-sectional view of a portion of a stator 10 of an electric machine 12 according to the prior art is shown. Figure 1The cross-sectional view of the stator 10 of the electric machine 12 in FIG. 1 shows the stator core 14, which may include stacked laminations (e.g., magnetic steel sheets) that enclose stator windings and coils 16 enclosed in an inner housing 18. Springs 20 are disposed in slots 22 formed in the inner housing 18. Core end rings 24 are disposed in the slots 22 to retain the stator core 14 and springs 20 in the inner housing 18. An outer housing 26 encloses the inner housing 18 to retain the stator core 14, springs 20, and core end rings 24 within the inner housing. To this extent, the inner housing 18, springs 20, core end rings 24, and outer housing 26 can work together to maintain axial and radial loads on the stator core 14 for retaining the core during operation, handling, and manufacturing of the electric machine 12. This allows the stator core 14 to withstand different temperature and / or environmental response loads that may occur during these instances.

[0040] exist Figure 1 In the motor 12 depicted in , the stator 10 does not have tight axial and radial spatial constraints that would preclude the use of springs 20 and core end rings 24 in slots 22 formed in the inner housing 18. Therefore, the springs 20 can be used to push directly against the stator core 14 to maintain axial forces in the core so that it can withstand impact loads. As mentioned above, motors with primary design requirements of compact size and weight savings typically do not have axial and radial space in the inner housing to accommodate springs that can maintain axial forces into the stator core. In particular, because these motors have such tight axial and radial spatial constraints, there is not enough mechanical or electrical clearance space to accommodate a spring in the inner housing that can push directly against the stator core to maintain it in axial compression to handle transient conditions that may occur during operation, handling, and manufacturing of the motor.

[0041] Figure 2 A schematic diagram of a front view of an end of a stator 28 for an electric machine 30, such as a generator or motor, is shown with tight radial and axial spatial constraints for implementing a spring in an inner housing. Figure 1 The stator core 14 of the stator 10 in the motor 12 depicted in FIG. Figure 2The stator 28 of the electric machine 30 shown in FIG. 1 includes a stator core 32 having stacked laminations enclosing stator windings and coils 34 (collectively referred to as "stator winding coils 34") enclosed in an inner housing 36 (e.g., a cooling jacket). In one embodiment, the stator core 32 may include a plurality of axially oriented slots 38 extending radially from a central axis of the stator core (a longitudinal axis extending through the center of the stator), wherein a plurality of stator winding coils 34 are disposed in the slots. After the stator winding coils 34 are disposed in the slots 38, a plurality of stator core wedges 40 are placed in a dovetail (not shown) formed in the stator 28. The stator core wedges 40 retain the stator winding coils 34 in the slots 38 and inhibit radial movement to prevent the coils from escaping from the slots. Phase ring connections or bus bars 42 interconnect leads 44 from the various stator winding coils 34. As electrical conductors, the phase ring connections or bus bars 42 connect the leads 44 of the stator winding coils 34 to a desired circuit including a phase.

[0042] The motor 30 may also include a retaining assembly 46 for use with Figure 2 36. The stator core 32 is retained within the tight radial and axial spatial constraints associated with the electric machine depicted in FIG. 36. In one embodiment, the retention assembly 46 may include a core end ring 48 disposed circumferentially at the axial ends of the stator core 32 to retain the core in the inner housing 36 and provide insulating material for electrical clearance. In addition to retaining the stator core 32 in the inner housing 36, the core end ring 48 may serve as a portion of the retention assembly 46 that may apply one or more of an axial load and a radial load to the stator core 32, which may keep the stator core in axial and / or radial compression to withstand different temperature and / or environmental impact loads that may occur during operation, handling, and manufacturing of the electric machine 30.

[0043] Figure 3 Additional details of the core end ring 48 are shown in FIG. Figure 3 As shown in , the core end ring 48 , which may include a non-metallic material such as plastic, may include a plurality of coil form retention features 50 configured to extend correspondingly between the plurality of slots 38 at the axial end of the stator core 32 . Figure 3 It is also shown that the core end ring 48 may include a flange feature 54 that protrudes outwardly from the plurality of coil form retaining features 50. When the core end ring 48 is circumferentially disposed at the axial end of the stator core 32, the flange feature 54 will be Figure 2 The axial end surface 36 of the inner housing shown in FIG. 1 protrudes axially outward.

[0044] Return to reference Figure 2, another portion of the retaining assembly 46 may include an axial end face 56 of the inner casing 36. In one embodiment, the axial end face 56 of the inner casing 36 includes a circumferentially extending formed profile having recessed portions 58 that protrude axially inward from the axial end face of the casing, the recessed portions alternating with non-recessed portions 60. For example, the formed profile of alternating recessed portions 58 and non-recessed portions 60 may include a scalloped profile having a plurality of spaced-apart scalloped (i.e., curved or semicircular) surfaces formed on the axial end face 56 of the inner casing 36. Having a formed profile (e.g., a scalloped profile) at the axial end face 56 of the inner casing 36, a portion of the core end ring 48 may extend axially outward from the formed profile at the axial end face beyond the recessed portion. In particular, the flange feature 54 ( Figure 3 ) may extend axially outward beyond the recessed portion (e.g., the scalloped surface) 58.

[0045] The retention assembly 46 may also include a core retention spring 62 that is circumferentially disposed at the axial end face 56 of the inner housing 36. The core retention spring 62 may be in direct contact with the core end ring 48 and the shaped contours of the inner housing 36. In essence, the flange feature 54 of the core end ring 48 is in spring-loaded connection with the core retention spring 62. This allows the core retention spring 62 to push against the core end ring 48, thereby applying or placing a force such as an axial load in the stator core 32, which forces the core to be held in axial compression, which may be a constant compression or a varying or changing compression. This allows the stator core 32 to withstand different temperature and / or environmental response loads that may occur during operation, handling, and manufacturing of the motor 30.

[0046] In one embodiment, the core retaining spring 62 may be implemented in the retaining assembly 46 as a segmented core retaining spring including a plurality of segmented core retaining springs. For example, the segmented core retaining spring 62 may include a segmented wave spring disposed around a shaped profile (e.g., a scalloped profile) at the axial end face 56 of the inner housing 36. In one embodiment, each of the segmented wave springs may be disposed at a selected recessed portion 58 (e.g., a scalloped surface) on the axial end face 56 of the inner housing 36 to facilitate a spring-loaded connection with the core retaining spring 62. In one embodiment, the segmented wave springs may be disposed at alternating recessed portions 58. Those skilled in the art will appreciate that this implementation of the segmented wave spring represents only one possible arrangement of the springs and is not meant to be limiting. For example, the segmented wave springs may be disposed at all recessed portions 58 on the axial end face 56 of the inner housing 36.

[0047] Figure 4 A schematic diagram of a perspective view of one of the segmented core retaining springs 62 according to an embodiment that may include a wave spring is shown. Figure 4As shown in , each segmented core retaining spring 62 may include a first protruding leg 64, a second protruding leg 66, and a movable portion 68 between the first and second protruding legs. The first and second protruding legs 64, 66 of each segmented core retaining spring 62 may be attached to a portion of the profile (i.e., one of the recessed portions 58 at the axial end surface 56 of the inner housing 36), and the movable portion 68 of the segmented core retaining spring may be in direct contact with the core end ring 48 to facilitate the spring loaded connection.

[0048] In one embodiment, if Figure 4 As shown in , each segmented core retaining spring 62 may include a through hole 70 in one or more of the first protruding leg 64 and the second protruding leg 66. The through hole 70 may be complementary to receive spring retaining hardware therein to secure one of the first protruding leg 64 and the second protruding leg 64 to the axial end face 56 of the inner housing 36. It should be understood that Figure 4 The segmented core retaining spring 62 depicted in the figure is representative of only one segmented wave spring that may be disposed about the axial end face 56 of the inner housing 36. For example, the segmented wave spring may have two through holes 70 disposed at both the first protruding leg 64 and the second protruding leg 66. In this arrangement, each through hole 70 is complementary to receive spring retaining hardware therein to secure the first protruding leg 64 and the second protruding leg 66 to the axial end face 56. In another embodiment, the segmented wave spring may not have through holes disposed on the first protruding leg 64 or the second protruding leg 66. In this arrangement, the first protruding leg 64 and the second protruding leg 66 may be disposed and secured in a core retaining spring feature disposed on the axial end face 56 of the inner housing 36.

[0049] For purposes of clarity in describing the retention assembly 46 and its components in connection with the various embodiments described herein, other components that may form part of the electric machine 30 are described below. Figure 2 as well as Figure 5-Figure 10 For example, the motor 30 may include a rotor and a rotor shaft mounted within the stator 28. The rotor may be wound in a field winding that generates a constant magnetic field that may interact with a stator winding coil 34 that may be fed by a system of three-phase AC voltage.

[0050] Now about Figure 5-Figure 10 Discussing additional details of the retention assembly 46 for retaining the stator core 32 in the electric machine 30 including the core end ring 48, the axial end face 56 of the inner housing 36, and the core retaining spring 62 according to one embodiment. Now referring to Figure 5 and Figure 8, these figures show additional details of aspects of the retaining assembly 46 related to the geometry at the axial end face 56 of the inner housing 36 that allows the core end ring 48 to be positioned protrudingly in such a tight axial and radial space near that face of the housing and not completely recessed or nested in the housing. For example, Figure 5 and Figure 8 The portion of the core end ring 48 (ie, the flange feature 54 ( FIG. 1 ) extending axially outward from the shaped contour of the axial end face 56 of the inner casing 36 is shown. Figure 3 ) portions). In particular, these portions of the core end ring 48 extend axially outward from the recessed portions 58 of the axial end face 56 of the inner housing 36. As these portions of the core end ring 48 extend axially outward from the recessed portions 58, the segmented core retention springs 62 disposed at selected recessed portions 58 on the axial end face 56 of the inner housing 36 may be placed on these portions of the core end ring 48 to be in direct contact therewith so as to facilitate a spring-loaded connection between the two components. To this extent, the segmented core retention springs 62 may be pressed against those selected axially extending portions of the core end ring 48 during the occurrence of an impact load. The pressing of the segmented core retention springs 62 against the core end ring 48 results in a force (axial load) being applied to the stator core 32 such that the primary load path of the force to the core is through the core end ring. Thus, the force applied to the stator core 32 may hold the core in axial compression during an impact load instance in which the stator core has a tendency to translate, deflect, or separate relative to the housing.

[0051] Figure 5 and Figure 8 as well as Fig. 6A , Figure 6B , Figure 7 and Fig. 9 Additional details of the core retaining spring features that may be provided on the axial end face 56 of the inner housing 36 to secure the core retaining spring 62 are shown. In one embodiment, the core retaining spring features of the retaining assembly may be provided by machining at a formed contour of the axial end face 56 of the inner housing 36. For example, the formed contour of the axial end face 56 may form an alternating pattern of recessed portions (e.g., a scalloped surface) with the core retaining spring features and recessed portions without the core retaining spring features.

[0052] In one embodiment, if Figure 5 , Fig. 6A and Figure 6BAs shown in , the core retaining spring feature disposed at the shaped contour of the axial end face 56 of the inner housing 36 may include an axially extending through hole 72 (e.g., a threaded hole) complementary to receive therein a spring retaining hardware 74 and a radially extending spring retaining groove or channel 76 formed in the axial end face opposite the through hole. The through hole 72 and the spring retaining hardware 74 may secure a portion of the core retaining spring 62 to the axial end face 56 of the inner housing 36, and the radially extending spring retaining groove 76 may receive therein another portion of the core retaining spring to secure the portion to the axial end face of the first housing.

[0053] The spring retaining hardware 74 may include any of a number of well-known fasteners that may facilitate a mechanical connection between two parts. For example, the spring retaining hardware 74 may include screws, bolts, pins, inserts, rivets, etc. In addition to these examples of fasteners, other methods may be used to secure the core retaining spring 62 to the axial end face 56 of the inner housing 36. A non-exhaustive list of these other methods includes bonding (e.g., adhesives) and welding (e.g., spot welding).

[0054] In another embodiment, Figure 7 , Figure 8 and Fig.10 As shown in , the core retaining spring feature provided at the formed contour of the axial end surface 56 of the inner housing 36 may include a pair of opposing radially extending spring retaining grooves 76 and an axially extending lip or flange feature 78 provided between the grooves. In this configuration, each spring retaining groove 76 is configured to receive a portion of the core retaining spring 62 therein. This inhibits axial and circumferential movement of the corresponding core retaining spring. A portion of the active portion of the core retaining spring 62 is seated below and in contact with the axially extending lip feature 78. In this manner, the axially extending lip feature 78 radially captures the portion of the active portion of the core retaining spring 62 seated below. Therefore, the spring retaining groove 76 and the axially extending lip feature 78 are used to inhibit circumferential, radial and axial movement of the segmented core retaining spring 62.

[0055] The core retention spring features depicted in the accompanying drawings are merely illustrative of several possibilities and are not meant to be limiting of the various embodiments. In one embodiment, the core retention spring feature may include two through holes 72 instead of just one through hole. For example, a first axially extending through hole 72 may be formed in a location in the recessed portion 58 of the axial end face 56 of the inner housing 36, while a second axially extending through hole 72 may be formed at an opposite end of the recessed portion. In this configuration, the first through hole and the second through hole 72 are both complementary to receive spring retention hardware 74 therein. In this manner, the first and second through holes 72 and corresponding spring retention hardware may secure a portion of the core retention spring 62 to the axial end face 56 of the inner housing 36, thereby inhibiting axial and circumferential movement of the segmented core retention spring 62.

[0056] Figure 2 , Figure 5 , Fig. 6A , Figure 6B , Figure 7 , Figure 8 and Fig. 9 The core retaining spring 62 is shown to include a segmented core spring such as a wave spring, but as mentioned above and in Fig.10 As described in , the core retaining spring may include a 360° spring such as a 360° wave spring. Fig.10 As shown in , the 360° wave spring can be disposed at the contoured portion of the axial end face 56 of the inner housing 36. For example, the 360° wave spring can be disposed entirely along the contoured portion of the axial end face 56 including the concave portion 58 (e.g., a scalloped surface) and the non-concave portion 60. In one embodiment, as Fig.10 As shown in , the 360° wave spring can be secured to the axial end face 56 of the inner housing 36 using any of the aforementioned spring retaining hardware 74. For example, the spring retaining hardware 74 is secured to the non-recessed portion 60 on the shaped contour of the axial end face 56.

[0057] although Fig.10 The use of spring retention hardware 74 to secure the 360° wave spring to the axial end face 56 of the inner housing 36 is shown, but it should be understood that other core retention spring features may be used to secure the 360° wave spring. For example, the 360° wave spring may be secured in a radially extending spring retention slot 76 disposed along the axial end face 56 of the inner housing 36 in the manner previously described. Moreover, these other core retention spring features may include an axially extending lip feature 78 to provide positive radially outboard retention of the spring, which is complementary to the axial and circumferential retention of the spring provided by the spring retention slot 76. It should be understood that the 360° wave spring may be secured to the axial end face 56 of the inner housing 36 using any of the other previously described methods including, but not limited to, bonding and welding.

[0058] By utilizing an outer housing to house an inner housing 36 that includes contoured profiles and core retaining spring features, an additional amount of positive radially outward retention of the core retaining spring 62 may be provided by the retaining assembly 46. For example, Fig. 9 An outer housing 80 is shown extending over the inner housing 36 and the segmented core retention spring 62. In this manner, the outer housing 80 can trap or contain the core retention spring 62 thereunder, thereby inhibiting outside radial movement of the spring. In particular, by covering the radially extending spring retention slots 76, the outer housing 80 can contain the segmented core retention spring 62 and inhibit outside radial movement of the spring, thereby additionally supplementing the radial movement inhibition that may be provided by using the axially extending lip feature 78 ( Figure 7 and Figure 8 ) to provide.

[0059] Figure 2 , Figure 5 , Fig. 6A , Figure 6B , Figure 7 , Figure 8 , Fig. 9 and Fig.10 The retention assembly depicted in is not meant to be limiting, as other methods may be implemented to provide axial load and / or radial load retention of the stator core in an electric machine. For example, in one embodiment, a low profile retention assembly may be achieved without the use of core end rings 48. In this embodiment, the stator core 32 at the axial end face 56 of the housing 36 may be shaped to exhibit features corresponding to the shape and characteristics of the core end rings at that location. For example, using Fig. 9 For reference, the axial face of the stator core 32 can be formed to present the shape of the core end ring at this location, that is, added to the axial end face portion of the stator core shown in the figure to eliminate the use of the core end ring 48. In this way, the core retaining spring 62 can be used to press or push directly into those features of the stator core that are shaped to correspond to the features of the core end ring. Pressing or pushing the core retaining spring 62 into these features can apply an axial load to the stator core.

[0060] In another embodiment, a low profile retention assembly may be provided to apply one or more of a radial load and an axial load into the stator core. For example, the stator core 32 and the core end ring 48 at the axial end face 56 of the housing 36 may be configured to have angled surfaces (e.g., tapered surfaces) formed between these components. Depending on the angled surfaces, the application of the core retention spring 62 to the surface may generate a resultant force vector into the surface that may be resolved as a radial load, an axial load, or both. Thus, these loads may be applied to the stator core 32 to hold it in compression in accordance with the corresponding loads.

[0061] From the description of the embodiments given herein, it is apparent that the subject disclosure presents an effective solution that addresses the challenges associated with smaller and lighter motors that lack axial and radial space to deploy springs such as 360° springs in an inner housing that houses the stator core in order to withstand impact loads that may occur during operation, handling, and manufacturing of the motor. The solution provided by the retaining assembly of various embodiments requires the use of an axial face of the inner housing to receive the spring. In this way, the spring can be pressed or pushed against the core end ring or the portion of the stator core that extends radially from the axial face. The pressing or pushing of the spring against these portions of the core end ring or the stator core applies a force (axial load and / or radial load) to the stator core. This force can keep the stator core in axial and / or radial compression.

[0062] The use of the retention assemblies described herein provides several benefits. For example, the low profile retention assemblies facilitate the manufacture and production of motors for which compact size and weight savings are primary design requirements. In addition, the retention assemblies of various embodiments allow for significantly more spring deflection in the axial direction, which is beneficial in accommodating a wide range of differential motor part interface movement and growth that may occur during motor operation, handling, and manufacturing. Moreover, the springs of the retention assemblies not only maintain an acceptable spring force during initial installation, but also maintain an acceptable force during higher temperature operation when thermal mismatches between the housing, core end rings, and stator core may occur.

[0063] The above description of the exemplary embodiments of the present disclosure, including the contents described in the abstract of the specification, is not intended to be exhaustive or to limit the disclosed embodiments to the precise form disclosed. Although specific embodiments and examples are described herein for the purpose of illustration, it can be appreciated by those skilled in the relevant art that various modifications are possible within the scope of these embodiments and examples. For example, parts, components, steps, and aspects from different embodiments may be combined or applied to other embodiments, even if not described in the present disclosure or depicted in the accompanying drawings. Therefore, since certain changes may be made in the above invention without departing from the spirit and scope of the present invention involved herein, it is intended that all the subjects described above shown in the accompanying drawings should be interpreted only as examples illustrating the inventive concept of this article, and should not be understood as limiting the present invention.

[0064] In this regard, although the disclosed subject matter has been described in conjunction with various embodiments and corresponding drawings, it should be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments to perform the same, similar, alternative or alternative functions of the disclosed subject matter without departing from the disclosed subject matter. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, but should be interpreted in accordance with the breadth and scope of the appended claims. For example, reference to "one embodiment" of the present invention is not intended to be interpreted as excluding the existence of other embodiments that also include the listed features.

[0065] In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Further, in the following claims, terms such as "first," "second," "third," "upper," "lower," "bottom," "top," and the like are used merely as labels and are not intended to impose numerical or positional requirements on their objects. The terms "substantially," "typically," and "approximately" represent conditions within reasonably achievable manufacturing and assembly tolerances relative to ideal desired conditions suitable for achieving the functional purpose of a component or assembly. Further, the limitations in the following claims are not written in a mean-plus-function format and are not intended to be interpreted as such limitations unless and until such claim limitations are explicitly followed by the description of the void function of other structures using the phrase "in a manner of..."

[0066] The above-described content includes examples of systems and methods for illustrating the disclosed subject matter. Of course, it is impossible to describe every combination of parts or modes here. It will be appreciated by those of ordinary skill in the art that many other combinations and arrangements of the claimed subject matter are possible. In addition, with respect to the term "including" or "comprising" adopted in the specific embodiments or claims, it is intended to be inclusive in a manner similar to the term "comprising", as "comprising" is translated when used as a transitional word in the claims. That is, unless explicitly stated to the contrary, an embodiment of "including", "comprising" or "having" an element or multiple elements with a specific attribute may include other such elements that do not have the attribute. In addition, the articles "one" and "a kind of" used in this specification and the accompanying drawings should generally be interpreted as meaning "one or more", unless otherwise noted or clear from the context for the singular form.

[0067] This written description uses examples to disclose several embodiments of the invention, including the best mode, and also enables a person of ordinary skill in the art to practice the embodiments of the invention, including making and using any device or system and performing any combined methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to a person of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

[0068] Further aspects of the invention are provided by the subject matter of the following clauses:

[0069] A retaining assembly for retaining a stator core in a stator of an electric machine, the retaining assembly comprising: a first housing for accommodating the stator core, the first housing having an axial end face, the axial end face having a circumferentially extending shaped profile, the profile having recessed portions protruding axially inwardly from the axial end face of the housing, the recessed portions alternating with non-recessed portions, wherein a portion of the stator core extends axially outwardly from the shaped profile at the axial end face of the first housing beyond the recessed portions; and a core retaining spring, the core retaining spring being circumferentially disposed at the axial end face of the first housing, the core retaining spring being in direct contact with the portion of the stator core extending axially outwardly from the shaped profile of the first housing and the shaped profile of the first housing, wherein the core retaining spring pushes against the portion of the stator core extending axially outwardly from the shaped profile of the first housing, thereby applying one or more of an axial load and a radial load to the stator core, the axial load and the radial load keeping the stator core in axial and / or radial compression.

[0070] A retaining assembly according to the preceding clause, wherein the formed profile of the first shell includes a fan-shaped profile having a plurality of spaced-apart fan-shaped surfaces formed on the axial end face of the first shell and a plurality of axially and radially extending core retaining spring features, the plurality of core retaining spring features being arranged at selected fan-shaped surfaces, wherein the fan-shaped profile forms an alternating pattern of fan-shaped surfaces with core retaining spring features and fan-shaped surfaces without core retaining spring features.

[0071] A retaining assembly according to any of the preceding clauses, wherein the multiple core retaining spring features include an axially extending through hole complementary to receive spring retaining hardware therein and a radially extending spring retaining groove opposite to the through hole, the through hole and the spring retaining hardware fix a portion of the core retaining spring to the axial end face of the first shell, and the radially extending spring retaining groove receives another portion of the core retaining spring therein to fix the portion to the axial end face of the first shell.

[0072] A retaining assembly according to any of the preceding clauses, wherein the plurality of core retaining spring features include a pair of opposing radially extending spring retaining grooves and an axially extending lip feature disposed between the grooves, wherein each spring retaining groove is configured to receive a portion of the core retaining spring therein, thereby inhibiting axial and circumferential movement of that portion of the core retaining spring, and the axially extending lip feature is configured to radially capture an additional portion of the core retaining spring thereunder, thereby inhibiting radial movement of the core retaining spring.

[0073] A retaining assembly according to any of the preceding clauses, wherein the plurality of core retaining spring features include a first axially extending through hole and a second axially extending through hole opposite to the first through hole, the first through hole and the second through hole being complementary to each other to receive spring retaining hardware therein, the first through hole and the second through hole and the corresponding spring retaining hardware being configured to fix a portion of the core retaining spring to the axial end face of the first housing, thereby inhibiting axial and circumferential movement of the portion of the core retaining spring.

[0074] A retaining assembly according to any of the preceding clauses, wherein the core retaining spring is a segmented core retaining spring, the segmented core retaining spring comprising a plurality of segmented core retaining springs, each segmented core retaining spring having a first protruding leg, a second protruding leg, and a movable portion between the first protruding leg and the second protruding leg, wherein the first protruding leg and the second protruding leg of each segmented core retaining spring are attached to the formed contour at the axial end face of the first shell, and the movable portion of the segmented core retaining spring is in direct contact with the portion of the stator core extending axially outward from the formed contour of the first shell, wherein each segmented core retaining spring is spaced apart from adjacent segmented core retaining springs on the formed contour at the axial end face of the first shell.

[0075] A retaining assembly according to any of the preceding clauses, wherein each segmented core retaining spring includes a through hole in one or more of the first protruding leg and the second protruding leg, the through holes being complementary to receive spring retaining hardware therein to secure one of the first protruding leg and the second protruding leg to the axial end face of the first housing.

[0076] According to any of the preceding clauses, the retaining assembly further comprises a second shell for accommodating the first shell, the second shell extending above the first shell and the core retaining spring, wherein the second shell traps the core retaining spring thereunder, thereby inhibiting radial movement of the outer side of the core retaining spring.

[0077] A retaining assembly for retaining a stator core in a stator of an electric motor, the retaining assembly comprising: a core end ring, the core end ring being circumferentially arranged at an axial end of the stator core; an inner housing for accommodating the stator core and the core end ring, the inner housing having an axial end face, the axial end face having a circumferentially extending fan-shaped profile, wherein a portion of the core end ring axially extends out from the fan-shaped profile at the axial end face of the inner housing; and a core retaining spring, the core retaining spring comprising a plurality of segmented core retaining springs circumferentially arranged at the axial end face of the inner housing, each segmented core retaining spring being formed by the inner housing. The axial end surface of the housing includes a structure to inhibit circumferential and radial movement of the core retaining spring, wherein each segmented core retaining spring is in direct contact with the portion of the core end ring that extends axially from the fan-shaped profile of the inner housing, and each segmented core retaining spring is pushed against the core end ring to apply one or more of an axial load and a radial load to the stator core, wherein the axial load and / or the radial load applied to the stator core via the core end ring by all of the segmented core retaining springs among the multiple segmented core retaining springs keeps the stator core in axial compression and / or radial compression.

[0078] A retaining assembly according to the preceding clause, wherein the circumferentially extending fan-shaped profile includes a plurality of spaced-apart fan-shaped surfaces formed on the axial end surface of the inner shell and a plurality of axially and radially extending core retaining spring features, the plurality of core retaining spring features being arranged at selected fan-shaped surfaces, wherein the fan-shaped profile forms an alternating pattern of fan-shaped surfaces with core retaining spring features and fan-shaped surfaces without core retaining spring features.

[0079] A retaining assembly according to any of the preceding clauses, wherein the multiple core retaining spring features include an axially extending through hole complementary to each other to receive spring retaining hardware therein and a radially extending spring retaining groove opposite to the through hole, the through hole and the spring retaining hardware fixing a portion of one of the segmented core retaining springs to the axial end face of the inner shell, and the radially extending spring retaining groove receiving another portion of the segmented core retaining spring therein to fix that portion of the segmented core retaining spring to the axial end face of the inner shell.

[0080] A retaining assembly according to any of the preceding clauses, wherein the multiple core retaining spring features include a pair of opposing radially extending spring retaining grooves and an axially extending lip feature disposed between the spring retaining grooves, wherein each spring retaining groove is configured to receive a portion of one of the segmented core retaining springs therein, thereby inhibiting axial and circumferential movement of the segmented core retaining spring, and the axially extending lip feature is configured to radially capture the segmented core retaining spring thereunder, thereby inhibiting radial movement of the segmented core retaining spring.

[0081] A retaining assembly according to any of the preceding clauses, wherein the multiple core retaining spring features include a first axially extending through hole and a second axially extending through hole opposite to the first through hole, the first through hole and the second through hole are complementary to receive spring retaining hardware therein, and the first through hole and the second through hole and the corresponding spring retaining hardware are configured to fix a portion of one of the segmented core retaining springs to the axial end face of the inner shell, thereby inhibiting axial and circumferential movement of the portion of the core retaining spring.

[0082] A retaining assembly according to any of the preceding clauses, wherein the plurality of segmented core retaining springs comprise segmented wave springs, each wave spring having a first protruding leg, a second protruding leg, and a movable portion between the first protruding leg and the second protruding leg, wherein the first protruding leg and the second protruding leg of each wave spring are attached to the fan-shaped profile at the axial end face of the inner shell, and the movable portion of the wave spring is in direct contact with the portion of the core end ring that extends axially from the fan-shaped profile of the inner shell, wherein each wave spring is spaced apart from an adjacent wave spring on the fan-shaped profile at the axial end face of the inner shell.

[0083] A retaining assembly according to any of the preceding clauses, wherein each wave spring includes a through hole in one or more of the first protruding leg and the second protruding leg, the through holes being complementary to receive spring retaining hardware therein to secure one of the first protruding leg and the second protruding leg to the axial end face of the inner housing.

[0084] According to any of the preceding clauses, the retaining assembly further comprises an outer shell for accommodating the inner shell, the outer shell extending above the inner shell and the plurality of segmented core retaining springs, wherein the outer shell traps the plurality of segmented core retaining springs thereunder, thereby inhibiting radial movement of the outer sides of the segmented core retaining springs.

[0085] An electric motor, the electric motor comprising: a stator core, the stator core having a plurality of axially oriented slots extending radially from a central axis of the stator core, wherein a plurality of stator winding coils are arranged in the slots; an inner housing for accommodating the stator core, the inner housing having an axial end face, the axial end face having a circumferentially extending fan-shaped profile, wherein a portion of the stator core axially extends out from the fan-shaped profile at the axial end face of the inner housing; a core retaining spring, the core retaining spring being circumferentially arranged at the axial end face of the inner housing, the core retaining spring being axially engaged with the stator core from the fan-shaped profile of the inner housing The portion extending outward is in direct contact with the fan-shaped profile of the inner housing, wherein the core retaining spring is pushed against the portion of the stator core that extends axially from the fan-shaped profile of the inner housing, and the core retaining spring applies one or more of an axial load and a radial load to the stator core, and the axial load and radial load keep the stator core in axial and / or radial compression; and an outer housing for accommodating the inner housing, the outer housing extending above the inner housing and the core retaining spring, wherein the outer housing traps the core retaining spring thereunder, thereby inhibiting outer radial movement of the core retaining spring.

[0086] An electric motor according to the preceding clause, wherein the circumferentially extending scalloped profile comprises a plurality of spaced scalloped surfaces formed on the axial end surface of the inner housing and a plurality of axially and radially extending core retaining spring features, wherein the scalloped profile forms an alternating pattern of scalloped surfaces with core retaining spring features and scalloped surfaces without core retaining spring features.

[0087] An electric machine as described in any of the preceding clauses, wherein the core retention spring feature comprises one or more of at least one radially extending spring retention slot and at least one axially extending through hole.

[0088] An electric motor according to any of the preceding clauses, wherein the core retaining spring is a segmented core retaining spring, the segmented core retaining spring comprising a plurality of segmented core retaining springs, each segmented core retaining spring having a first protruding leg, a second protruding leg, and a movable portion between the first protruding leg and the second protruding leg, wherein the first protruding leg and the second protruding leg of each segmented core retaining spring are attached to the fan-shaped profile at the axial end face of the inner housing, and the movable portion of the segmented core retaining spring is in direct contact with the portion of the stator core axially extending from the fan-shaped profile of the inner housing, wherein each segmented core retaining spring is spaced apart from adjacent segmented core retaining springs on the fan-shaped profile at the axial end face of the inner housing.

Claims

1. A retaining assembly (46) for retaining a stator core (32) in a stator (28) of an electric machine (30), the retaining assembly comprising: a first housing (36) for accommodating the stator core (32), the first housing (36) having an axial end face (56), the axial end face having a circumferentially extending shaped profile, the profile having recessed portions (58) projecting axially inwardly from the axial end face (56) of the housing (36), the recessed portions alternating with non-recessed portions (60), wherein a portion of the stator core (32) extends axially outwardly from the shaped profile at the axial end face (56) of the first housing (36) beyond the recessed portions (58); and A core retaining spring (62) is circumferentially arranged at the axial end surface (56) of the first shell (36), and the core retaining spring (62) is in direct contact with the portion of the stator core (32) extending axially outward from the formed contour of the first shell (36) and the formed contour of the first shell (36), wherein the core retaining spring (62) pushes against the portion of the stator core (32) extending axially outward from the formed contour of the first shell (36), thereby applying one or more of an axial load and a radial load to the stator core (32), and the axial load and the radial load keep the stator core (32) in axial and / or radial compression.

2. A retaining assembly (46) according to claim 1, wherein the formed profile of the first shell (36) includes a fan-shaped profile, the fan-shaped profile having a plurality of spaced-apart fan-shaped surfaces formed on the axial end surface (56) of the first shell (36) and a plurality of axially and radially extending core retaining spring features, the plurality of core retaining spring features being arranged at selected fan-shaped surfaces, wherein the fan-shaped profile forms an alternating pattern of fan-shaped surfaces with core retaining spring features and fan-shaped surfaces without core retaining spring features.

3. A retaining assembly (46) according to claim 2, wherein the plurality of core retaining spring features include an axially extending through hole (70) complementary to receive spring retaining hardware (74) therein and a radially extending spring retaining slot (76) opposite the through hole (70), the through hole (70) and the spring retaining hardware (74) securing a portion of the core retaining spring (62) to the axial end surface (56) of the first housing (36), and the radially extending spring retaining slot (76) receiving another portion of the core retaining spring (62) therein to secure the portion to the axial end surface (56) of the first housing (36).

4. A retaining assembly (46) according to claim 2, wherein the plurality of core retaining spring features include a pair of opposing radially extending spring retaining grooves (76) and an axially extending lip feature (78) disposed between the grooves (76), wherein each spring retaining groove (76) is configured to receive a portion of the core retaining spring (62) therein, thereby inhibiting axial and circumferential movement of the portion of the core retaining spring (62), and the axially extending lip feature (78) is configured to radially capture an additional portion of the core retaining spring (62) thereunder, thereby inhibiting radial movement of the core retaining spring (62).

5. A retaining assembly (46) according to claim 2, wherein the plurality of core retaining spring features include a first axially extending through hole (72) and a second axially extending through hole (72) opposite to the first through hole, the first through hole and the second through hole (72) being complementary to each other to receive spring retaining hardware (74) therein, the first through hole and the second through hole (72) and the corresponding spring retaining hardware (74) being configured to fix a portion of the core retaining spring (62) to the axial end surface (56) of the first housing (36), thereby inhibiting axial and circumferential movement of the portion of the core retaining spring (62).

6. The retaining assembly (46) according to claim 1, wherein the core retaining spring (62) is a segmented core retaining spring (62), the segmented core retaining spring comprising a plurality of segmented core retaining springs (62), each segmented core retaining spring (62) having a first protruding leg (64), a second protruding leg (66), and a movable portion (68) between the first protruding leg (64) and the second protruding leg (66), wherein the first protruding leg (64) and the second protruding leg (66) of each segmented core retaining spring (62) are The second protruding leg (66) is attached to the formed contour at the axial end surface (56) of the first housing (36), and the movable portion (68) of the segmented core retaining spring (62) is in direct contact with the portion of the stator core (32) extending axially outward from the formed contour of the first housing (36), wherein each segmented core retaining spring (62) is spaced apart from an adjacent segmented core retaining spring (62) on the formed contour at the axial end surface (56) of the first housing (36).

7. A retaining assembly (46) according to claim 6, wherein each segmented core retaining spring (62) includes a through hole (70) in one or more of the first protruding leg (64) and the second protruding leg (66), and the through holes (70) are complementary to receive spring retaining hardware (74) therein to secure one of the first protruding leg (64) and the second protruding leg (66) to the axial end surface (56) of the first housing (36).

8. The retaining assembly (46) according to claim 1 further comprises a second shell (80) for accommodating the first shell (36), the second shell (80) extending above the first shell (36) and the core retaining spring (62), wherein the second shell (36) traps the core retaining spring (62) thereunder, thereby inhibiting radial movement of the outer side of the core retaining spring (62).

9. A retaining assembly (46) for retaining a stator core (32) in a stator (28) of an electric machine (30), the retaining assembly comprising: a core end ring (48) circumferentially disposed at an axial end of the stator core (32); An inner housing (36) for accommodating the stator core (32) and the core end ring (48), the inner housing (36) having an axial end surface (56) having a circumferentially extending fan-shaped profile, wherein a portion of the core end ring (48) axially extends from the fan-shaped profile at the axial end surface (56) of the inner housing (36); and A core retaining spring (62), the core retaining spring comprising a plurality of segmented core retaining springs (62) circumferentially arranged at the axial end surface (56) of the inner housing (36), each segmented core retaining spring (62) being contained by the axial end surface (56) of the inner housing (36) to inhibit circumferential and radial movement of the core retaining spring (62), wherein each segmented core retaining spring (62) is in direct contact with the portion of the core end ring (48) extending axially from the fan-shaped profile of the inner housing (36), each segmented core retaining spring (62) is pushed against the core end ring (48) to apply one or more of an axial load and a radial load to the stator core (32), wherein the axial load and / or the radial load applied to the stator core (32) by all of the segmented core retaining springs (62) via the core end ring (48) keeps the stator core (32) in axial compression and / or radial compression.

10. A retaining assembly (46) according to claim 9, wherein the circumferentially extending scalloped profile includes a plurality of spaced-apart scalloped surfaces formed on the axial end surface (56) of the inner shell (36) and a plurality of axially and radially extending core retaining spring features, the plurality of core retaining spring features being arranged at selected scalloped surfaces, wherein the scalloped profile forms an alternating pattern of scalloped surfaces having core retaining spring features and scalloped surfaces without core retaining spring features.

11. A retaining assembly (46) as described in claim 10, wherein the plurality of core retaining spring features include an axially extending through hole (72) complementary to receive spring retaining hardware (74) therein and a radially extending spring retaining slot (76) opposite the through hole (72), the through hole (72) and the spring retaining hardware (74) securing a portion of one of the segmented core retaining springs (62) to the axial end surface (56) of the inner housing (36), and the radially extending spring retaining slot (76) receiving another portion of the segmented core retaining spring (62) therein to secure the portion of the segmented core retaining spring (62) to the axial end surface (56) of the inner housing (36).

12. A retaining assembly (46) according to claim 10, wherein the plurality of core retaining spring features include a pair of opposing radially extending spring retaining grooves (76) and an axially extending lip feature (78) disposed between the spring retaining grooves (76), wherein each spring retaining groove (76) is configured to receive a portion of one of the segmented core retaining springs (62) therein, thereby inhibiting axial and circumferential movement of the segmented core retaining spring (62), and the axially extending lip feature (78) is configured to radially capture the segmented core retaining spring (62) thereunder, thereby inhibiting radial movement of the segmented core retaining spring (62).

13. A retaining assembly (46) according to claim 10, wherein the plurality of core retaining spring features include a first axially extending through hole (72) and a second axially extending through hole (72) opposite the first through hole (72), the first through hole and the second through hole being complementary to each other to receive spring retaining hardware (74) therein, the first through hole and the second through hole (72) and the corresponding spring retaining hardware (74) being configured to secure a portion of one of the segmented core retaining springs (62) to the axial end surface (56) of the inner shell (36), thereby inhibiting axial and circumferential movement of the portion of the core retaining spring (62).

14. A retaining assembly (46) according to claim 9, wherein the plurality of segmented core retaining springs (62) include segmented wave springs, each wave spring having a first protruding leg (64), a second protruding leg (66), and a movable portion (68) between the first protruding leg (64) and the second protruding leg (66), wherein the first protruding leg (64) and the second protruding leg (66) of each wave spring are attached to the fan-shaped profile at the axial end surface (56) of the inner housing (36), and the movable portion (68) of the wave spring is in direct contact with the portion of the core end ring (48) extending axially from the fan-shaped profile of the inner housing (36), wherein each wave spring (20) is spaced apart from an adjacent wave spring (20) on the fan-shaped profile at the axial end surface (56) of the inner housing (36).

15. A retaining assembly (46) according to claim 14, wherein each wave spring includes a through hole (70) in one or more of the first protruding leg (64) and the second protruding leg (66), and the through holes (70) are complementary to receive spring retention hardware (74) therein to secure one of the first protruding leg (64) and the second protruding leg (66) to the axial end surface (56) of the inner housing (36).

16. The retaining assembly (46) according to claim 9, the pool assembly also includes an outer shell (80) for accommodating the inner shell (36), the outer shell (80) extending above the inner shell (36) and the plurality of segmented core retaining springs (62), wherein the outer shell (80) traps the plurality of segmented core retaining springs (62) thereunder, thereby inhibiting radial movement of the outer side of the segmented core retaining springs (62).

17. An electric motor (30), comprising: a stator core (32) having a plurality of axially oriented slots (38) extending radially from a central axis of the stator core (32), wherein a plurality of stator winding coils (34) are disposed in the slots (38), An inner housing (36) for accommodating the stator core (32), the inner housing (36) having an axial end surface (56), the axial end surface having a circumferentially extending sector-shaped profile, wherein a portion of the stator core (32) axially extends out from the sector-shaped profile at the axial end surface (56) of the inner housing (36); a core retaining spring (62) circumferentially disposed at the axial end surface (56) of the inner housing (36), the core retaining spring (62) being in direct contact with the portion of the stator core (32) extending axially outward from the fan-shaped profile of the inner housing (36) and the fan-shaped profile of the inner housing (36), wherein the core retaining spring (62) pushes against the portion of the stator core (32) extending axially from the fan-shaped profile of the inner housing (36), the core retaining spring (62) applying one or more of an axial load and a radial load to the stator core (32), the axial load and the radial load keeping the stator core (32) in axial and / or radial compression; and An outer housing (80) for accommodating the inner housing (36), the outer housing (80) extending above the inner housing (36) and the core retaining spring (62), wherein the outer housing (80) traps the core retaining spring (62) thereunder, thereby inhibiting radial movement of the outer side of the core retaining spring (62).

18. The electric machine (30) of claim 17, wherein the circumferentially extending scalloped profile comprises a plurality of spaced scalloped surfaces and a plurality of axially and radially extending core retention spring features formed on the axial end surface (56) of the inner housing (36), wherein the scalloped profile forms an alternating pattern of scalloped surfaces with core retention spring features and scalloped surfaces without core retention spring features.

19. The electric machine (30) of claim 17, wherein the core retention spring feature comprises one or more of at least one radially extending spring retention slot (76) and at least one axially extending through hole (72).

20. The motor (30) of claim 17, wherein the core retaining spring (62) is a segmented core retaining spring (62), the segmented core retaining spring comprising a plurality of segmented core retaining springs (62), each segmented core retaining spring (62) having a first protruding leg (64), a second protruding leg (66), and a movable portion (68) between the first protruding leg (64) and the second protruding leg (66), wherein the first protruding leg (64) and the second protruding leg (66) of each segmented core retaining spring (62) are The second protruding leg (66) is attached to the fan-shaped profile at the axial end surface (56) of the inner housing (36), and the movable portion (68) of the segmented core retaining spring (62) is in direct contact with the portion of the stator core (32) extending axially from the fan-shaped profile of the inner housing (36), wherein each segmented core retaining spring (62) is spaced apart from an adjacent segmented core retaining spring (62) on the fan-shaped profile at the axial end surface (56) of the inner housing (36).

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