Motor assembly fastened only with polymers and method for manufacturing same

Abstract

Motor assembly fastened only with polymer and method of manufacturing the same. A motor assembly includes: a housing having a generally cylindrical inner surface that defines a generally cylindrical cavity within the housing; a stator operably disposed within the generally cylindrical cavity, the stator including a plurality of stacked laminations, wherein each lamination has an outer peripheral edge and a plurality of finger-like elements extending inwardly; and a polymer layer disposed between the generally cylindrical outer surface of the stator and the generally cylindrical inner surface of the housing so as to fasten the stator to the housing by the polymer. A method of manufacturing a motor assembly includes: disposing the stator within the housing such that a gap is defined between the stator and the housing and the stator is not directly connected to the housing, and substantially filling the gap with a polymer so as to be able to fasten the stator to the housing only by the polymer.

Description

Technical Field

[0001] The present disclosure relates to a motor assembly that secures a stator to a motor housing using only a polymer, and a method of manufacturing such a motor assembly. Background Art

[0002] A conventional motor has a shaft attached to a rotatable rotor that is nested within a stator, and the stator is in turn housed within a housing. The rotor typically has an overall cylindrical shape, and the stator typically has a hollow cylindrical shape with an inner surface that is cylindrical (matching the size and shape of the rotor) and an outer surface that is also typically cylindrical (matching the interior of the housing or otherwise fitting therein).

[0003] The stator is typically made of flat circular metal laminations stacked together. Each lamination has a plurality of inwardly extending fingers, and some (or all) of the laminations have a plurality of ears or tabs that extend outwardly from the circular outer edge of the lamination. These ears or tabs are used to mechanically secure the laminations (and thus the stator) to the housing.

[0004] Enameled copper wire is used to form windings around the inwardly extending fingers of the laminations. During operation of the motor, the housing serves as a ground, and stray currents can flow from the stator windings to the grounded housing. Additionally, the enameled wire acts as a resistor-capacitor network, which can cause fluctuations in these stray currents. Together, these stray currents and capacitance fluctuations can cause undesirable electrical noise in the motor, which may require additional countermeasures to filter out such noise. Summary of the Invention

[0005] According to one embodiment, a motor assembly includes: a housing having a generally cylindrical inner surface that defines a generally cylindrical cavity within the housing; a stator operably disposed within the generally cylindrical cavity, the stator including a plurality of stacked laminations, wherein each lamination has an outer circular perimeter and a plurality of finger elements that extend inwardly toward the center of the lamination; and a polymer layer disposed between the generally cylindrical outer surface of the stator and the generally cylindrical inner surface of the housing, thereby securing the stator to the housing by the polymer. A gap having a generally cylindrical housing shape can be defined between the stator and the housing, and the polymer layer substantially fills the gap. The polymer can have material properties that provide a predetermined electrical filtering of electrical noise between the stator and the housing. Optionally, a network of cooling channels can be formed in the polymer layer by forming a network of sacrificial elements made of a sacrificial material on the generally cylindrical outer surface of the stator and then removing the sacrificial material after the polymer has cured.

[0006] The motor assembly can be configured such that no laminations are directly connected to the housing, and / or such that the stator is not directly connected to the housing. This embodiment can also be configured such that the stator is fastened to the housing only by the polymer.

[0007] The motor assembly can further include a rotor operably disposed within a generally cylindrical inner stator cavity. This arrangement can be configured such that the polymer layer effectively prevents the stator from rotating relative to the housing. The motor assembly can further include an arcuate metal strip circumferentially disposed within the polymer layer, wherein the arcuate metal strip can be configured in one of the following configurations: (i) a flat shape configuration, wherein the arcuate metal strip is spaced apart from both the stator and the housing, and (ii) a wavy configuration, wherein the arcuate metal strip is arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator or the housing. In the wavy configuration, the arcuate metal strip can be integral with the outer peripheral edge of one of the laminations.

[0008] The housing can include a plurality of protrusions, each protruding inwardly from a generally cylindrical inner surface, and the stator can include a plurality of ridges, each protruding outwardly from a generally cylindrical outer surface, wherein the protrusions and the ridges can be interleaved with each other.

[0009] According to another embodiment, a motor assembly includes: (i) a metal housing having a generally cylindrical inner surface that defines a generally cylindrical cavity within the housing; (ii) a stator operably disposed within the generally cylindrical cavity, the stator including a plurality of stacked metal laminations, wherein each lamination has an outer peripheral edge and a plurality of finger-like elements extending inwardly toward the center of the lamination, wherein a gap having a generally cylindrical shell shape is defined between the stator and the housing, and no lamination is directly connected to the housing; and (iii) a polymer layer substantially filling the gap such that the stator is fastened to the housing only by the polymer. In this embodiment, the polymer has material properties that provide a predetermined electrical filtering of electrical noise between the stator and the housing.

[0010] The motor assembly can further include a rotor operably disposed within a generally cylindrical inner stator cavity, wherein the polymer layer effectively prevents the stator from rotating relative to the housing during operation of the motor assembly. The motor assembly can further include an arcuate metal strip circumferentially disposed within the polymer layer, wherein the arcuate metal strip can be configured in one of the following configurations: (i) a flat shape configuration, wherein the arcuate metal strip is spaced apart from both the stator and the housing, and (ii) a wavy configuration, wherein the arcuate metal strip is arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator or the housing.

[0011] According to another embodiment, a method of manufacturing an electric motor assembly includes: disposing a stator within a housing such that a gap is defined between the stator and the housing and the stator is not directly connected to the housing, and substantially filling the gap with a polymer such that the stator is fastened to the housing only by the polymer. The method may further include curing the polymer such that the stator is fastened to the housing only by the polymer. In this embodiment, the polymer may have material properties that provide a predetermined electrical filtering of electrical noise between the stator and the housing when the polymer is cured. The method may further include inserting an arcuate metal strip within the gap, wherein the arcuate metal strip may be configured in one of the following configurations: (i) a flat shape configuration in which the arcuate metal strip is spaced apart from both the stator and the housing, and (ii) a wavy configuration in which the arcuate metal strip is arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator or the housing. The method may also include forming a network of sacrificial elements made of a sacrificial material on a generally cylindrical outer surface of the stator, and removing the sacrificial material after the polymer is cured to form a network of cooling channels on the generally cylindrical outer surface of the stator.

[0012] The present invention also provides the following technical solutions:

[0013] 1. An electric motor assembly, comprising:

[0014] A housing having a generally cylindrical inner surface that defines a generally cylindrical cavity within the housing;

[0015] A stator operably disposed within the generally cylindrical cavity, the stator including a plurality of stacked laminations, wherein each lamination has an outer peripheral edge and a plurality of finger-like elements extending inwardly toward the center of the lamination; and

[0016] A polymer layer disposed between the generally cylindrical outer surface of the stator and the generally cylindrical inner surface of the housing such that the stator is bonded to the housing by the polymer.

[0017] 2. The electric motor assembly according to technical solution 1, wherein a gap having a generally cylindrical shell shape is defined between the stator and the housing, and wherein the polymer layer substantially fills the gap.

[0018] 3. The electric motor assembly according to technical solution 1, wherein none of the laminations are directly connected to the housing.

[0019] 4. The electric motor assembly according to technical solution 1, wherein the stator is not directly connected to the housing.

[0020] 5. The motor assembly according to Technical Solution 1, wherein the stator is fastened to the housing only by the polymer.

[0021] 6. The motor assembly according to Technical Solution 1, further comprising:

[0022] A rotor operably disposed within a generally cylindrical inner stator cavity.

[0023] 7. The motor assembly according to Technical Solution 1, wherein the polymer layer effectively prevents rotation of the stator relative to the housing.

[0024] 8. The motor assembly according to Technical Solution 1, further comprising:

[0025] Bow-shaped metal strips circumferentially disposed within the polymer layer, wherein the bow-shaped metal strips are configured in one of the following configurations: (i) a flat shape configuration, wherein the bow-shaped metal strips are spaced apart from both the stator and the housing, and (ii) a wavy configuration, wherein the bow-shaped metal strips are arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator or the housing.

[0026] 9. The motor assembly according to Technical Solution 8, wherein in the wavy configuration, the bow-shaped metal strips are integral with the outer peripheral edge of one of the laminations.

[0027] 10. The motor assembly according to Technical Solution 1, wherein the polymer has material properties that provide a predetermined electrical filtering of electrical noise between the stator and the housing.

[0028] 11. The motor assembly according to Technical Solution 1, wherein the housing includes a plurality of protrusions, each of which extends inwardly from the generally cylindrical inner surface, and the stator may include a plurality of ridges, each of which extends outwardly from the generally cylindrical outer surface, wherein the protrusions and the ridges are staggered with each other.

[0029] 12. The motor assembly according to Technical Solution 1, wherein a network of cooling channels is formed in the polymer layer by forming a network of sacrificial elements made of a sacrificial material on the cylindrical outer surface of the stator and then removing the sacrificial material after the polymer has cured.

[0030] 13. A motor assembly, comprising:

[0031] A metal housing having a generally cylindrical inner surface that defines a generally cylindrical cavity within the housing;

[0032] A stator operably disposed within the generally cylindrical cavity, the stator including a plurality of stacked metal laminations, wherein each lamination has an outer peripheral edge and a plurality of finger-like elements extending inwardly toward the center of the lamination, wherein a gap having a generally cylindrical shell shape is defined between the stator and the housing and no one of the laminations is directly connected to the housing; and

[0033] A polymer layer substantially filling the gap disposed between the outer cylindrical surface of the stator and the inner cylindrical surface of the housing such that the stator is fastened to the housing only by the polymer; and

[0034] Wherein the polymer has material properties that provide a predetermined electrical filtering of electrical noise between the stator and the housing.

[0035] 14. The motor assembly according to aspect 13, further comprising:

[0036] A rotor operably disposed within a generally cylindrical inner stator cavity, wherein the polymer layer effectively prevents rotation of the stator relative to the housing during operation of the motor assembly.

[0037] 15. The motor assembly according to aspect 13, further comprising:

[0038] An arcuate metal strip circumferentially disposed within the polymer layer, wherein the arcuate metal strip is configured in one of the following configurations: (i) a flat shape configuration, wherein the arcuate metal strip is spaced apart from both the stator and the housing, and (ii) a wavy configuration, wherein the arcuate metal strip is arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator and the housing.

[0039] 16. A method of manufacturing a motor assembly, comprising:

[0040] Disposing the stator within the housing such that a gap is defined between the stator and the housing and the stator is not directly connected to the housing; and

[0041] Substantially filling the gap with a polymer capable of fastening the stator to the housing only by the polymer.

[0042] 17. The method according to aspect 16, further comprising:

[0043] Curing the polymer such that the stator is fastened to the housing only by the polymer.

[0044] 18. The method according to aspect 16, wherein the polymer has the following material properties: when the polymer is cured, the material properties provide a predetermined electrical filtering of electrical noise between the stator and the housing.

[0045] 19. The method according to aspect 16, further comprising:

[0046] Inserting an arcuate metal strip into the gap, wherein the arcuate metal strip is configured in one of the following configurations: (i) a flat shape configuration, wherein the arcuate metal strip is spaced apart from both the stator and the housing, and (ii) a wavy configuration, wherein the arcuate metal strip is arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator or the housing.

[0047] 20. The method according to aspect 17, further comprising:

[0048] Forming a network of sacrificial elements made of a sacrificial material on a generally cylindrical outer surface of the stator; and

[0049] Removing the sacrificial material after the polymer is cured to form a network of cooling channels on the generally cylindrical outer surface of the stator. Description of the Drawings

[0050] When considered in conjunction with the drawings, the above and other features and advantages of the present teachings, as well as other features and advantages, will be apparent from the following detailed description of some of the best modes and other embodiments for carrying out the present teachings as defined in the appended claims.

[0051] Figure 1 is a schematic cross-sectional front view of the housing and stator laminations of a conventional motor.

[0052] Figure 2 is a schematic cross-sectional front view of a motor assembly.

[0053] Figures 3 - 5 are schematic partial cross-sectional side views of a motor assembly according to first, second, and third variants of the motor assembly, respectively.

[0054] Figure 6 is a schematic exploded partial cross-sectional front view of a motor assembly.

[0055] Figures 7 - 8 is a schematic cross-sectional close-up view of a portion of the housing and stator laminations of a motor, which respectively show its electrical and mechanical properties.

[0056] Figure 9A schematic cross-sectional close-up view of a part of a motor assembly, which shows its mechanical characteristics.

[0057] Figure 10 A schematic cross-sectional close-up view of a part of a motor assembly including an arcuate metal strip configured in a flat shape, which shows its mechanical characteristics.

[0058] Figure 11 A schematic cross-sectional close-up view of a part of a motor assembly including an arcuate metal strip configured in a wavy shape, which shows its mechanical characteristics.

[0059] Figure 12 A schematic cross-sectional close-up view of a part of a motor assembly including an arcuate metal strip configured in a wavy shape, wherein the arcuate metal strip is integral with the stator laminations.

[0060] Figure 13 A schematic cross-sectional close-up view of a part of a motor assembly, which shows its electrical characteristics.

[0061] Figure 14 A schematic cross-sectional close-up view of a part of a motor assembly, which shows housing protrusions and stator lamination bulges that intersect with each other.

[0062] Figures 15 - 16 Flowcharts showing a first method and a second method for manufacturing a motor assembly, respectively.

[0063] Figures 17 - 20 A schematic cross-sectional front view showing successive steps for forming a cooling channel in a motor assembly using a sacrificial element. Detailed Description

[0064] Now referring to the accompanying drawings, in which like reference numerals represent like components in several views, a motor assembly 20 and methods 100, 200 for manufacturing the motor assembly 20 are shown and described herein.

[0065] Figure 1 A schematic cross-sectional view of a housing 11 and a stator 12s of a conventional motor 10 is shown. As described above, the stator 12s is typically made of flat metal laminations 12 stacked together, with enameled copper wire (not shown) wound around inwardly extending fingers 19 of the laminations 12. As Figure 1As shown, the cross-section of the housing 11 can be generally annular, or it can take other shapes (e.g., rectangular), but in most cases, the housing 11 will have a generally cylindrical (or a cross-section that appears circular) inner surface 11is, which is consistent with the generally cylindrical outer surface 15s of the stator 12s. The housing 11 also has a plurality of lugs or mounting points 13 extending inwardly from the inner surface 11is of the housing. Each lamination 12 has a generally circular outer periphery 15, such that when the laminations 12 are stacked together they form the stator 12s, and the generally circular outer peripheries 15 of all the laminations 12 together form the generally cylindrical outer surface 15s of the stator 12s. Some or all of the laminations 12 also include a plurality of tabs 14 extending outwardly from the outer peripheral edge 15. The tabs 14 have holes 16 that are aligned with corresponding holes in the lugs or mounting points 13, such that fasteners (e.g., bolts, not shown) can be used to mechanically fasten the laminations 12 to the housing 11, and thereby mechanically fasten the entire stator 12s to the housing 11. This mechanical fastening centers and co-axially orients the stator 12s relative to the inner surface 11is of the housing (thus providing a generally uniform gap or spacing 9 between the outer surface 15s of the stator 12s and the inner surface 11is of the housing 11), and also prevents the stator 12s from rotating within the housing 11 during operation of the motor 10.

[0066] Figure 7 A schematic cross-sectional close-up view of a portion of the housing 11 and stator laminations 12 is shown, which illustrates its electrical characteristics. (It should be noted that although the figures show the laminations 12, these figures can also be considered applicable to an arrangement where the stator 12s replaces the laminations 12.) As Figure 7 shown, the copper wire 17, the enamel coating 18, the laminations 12, and the housing 11 can be considered to form a sandwich structure or arrangement, where the copper wire 17 has a resistance R17, the enamel coating 18 has a resistance R18 and a capacitance C18, the laminations 12 (or stator 12s) have a resistance R12, and the housing 11 serves as a ground Gnd. This arrangement shows how current leaks from the copper wire 17 through the enamel coating 18 and the laminations 12 to the ground Gnd, and how the enamel coating 18 creates capacitive fluctuations in the current leakage due to the capacitive effect of the coating. These leaks and fluctuations together cause or contribute to electrical noise in the motor 10 and its electrical system, which can also affect adjacent electrical components and systems.

[0067] Figure 8A schematic cross-sectional close-up view showing a part of the housing 11 and the stator lamination 12 or the stator 12s is presented, which shows its mechanical characteristics. The lamination / stator 12, 12s can be regarded as acting like a spring K12, which is connected in series with another spring K11 representing the housing. (Alternatively, K12 can also include the copper wire 17 and the enamel coating 18 of the stator winding.) Therefore, the stator-housing combination 12s, 11 can be regarded as a mechanical system and thus has resonance frequencies, harmonic nodes, and other characteristics of a mechanical system, which may cause or be susceptible to various vibrations, etc.

[0068] The motor assembly 20 and the methods 100, 200 for manufacturing the motor assembly 20 described herein provide a unique combination of features and advantages that help mitigate the above-mentioned electrical and mechanical challenges.

[0069] Figure 2 An embodiment of the motor assembly 20 that addresses these challenges is shown. The motor assembly 20 includes: a housing 22 having a generally cylindrical inner surface 24 that defines a generally cylindrical cavity 26 within the housing 22; and a stator 40 operably disposed within the generally cylindrical cavity 26. The stator 40 is composed of a plurality of stacked laminations 42, where each lamination 42 has an outer peripheral edge 43 and a plurality of finger-like elements 45 that extend inwardly towards the center of the lamination 42 and terminate at an inner peripheral edge 46. (The outer peripheral edge 43 and the inner peripheral edge 46 can be generally circular and concentric with each other.) Different from the Figure 1 conventional arrangement shown, it should be noted that in Figure 2 , no lugs or mounting points 13 extend inwardly from the housing 22, no tabs 14 extend outwardly from the lamination 42 or the stator 40, and no direct mechanical connection is provided between the stator 40 and the housing 22. Instead, a circumferential gap or spacing 48 is provided between the stator 40 and the housing 22, and the gap 48 is filled (partially or completely) by a polymer 50. In other words, a polymer layer 50 is disposed between the generally cylindrical outer surface 44 of the stator 40 and the generally cylindrical inner surface 24 of the housing 22 such that the stator 40 is fastened to the housing 22 by the polymer 50. In this arrangement, the gap 48 can have a generally cylindrical shell shape 49 between the stator 40 and the housing 22, where the polymer layer 50 substantially fills the gap 48.

[0070] The polymer 50 may have material properties that provide a predetermined electrical filtering of electrical noise between the stator 40 and the housing 22. For example, the polymer 50 may contain graphene or other conductive, semi-conductive, or insulating materials to facilitate electrical noise filtering. Moreover, the polymer 50 itself may be made of a material selected to optimally minimize, mitigate, or prevent electrical noise and / or alter its electrical properties. The polymer 50 may also have mechanical and material properties (e.g., density, hardness, elasticity, damping properties, tensile strength, melting point, etc.) that make it suitable for providing a desired combination of rigidity and flexibility while fastening or bonding the stator 40 to the housing 22. The polymer 50 may be a thermoplastic material or a thermosetting material.

[0071] The motor assembly 20 may be configured such that no laminations 42 are directly connected to the housing 22, and / or such that the stator 40 is not directly connected to the housing 22. In the absence of mechanical fasteners or features such as Figure 1 The motor assembly 20 may also be configured such that the stator 40 is secured to the housing 22 solely by the polymer 50 , with the lugs or mounting points 13 and tabs 14 shown in FIG.

[0072] Figures 3 - 5 Schematic partial cross-sectional views of the motor assembly 20 according to the first, second and third modifications of the motor assembly 20 are shown respectively. Figure 3 In the first variation shown, the housing 22 has an "open can" shape with a generally cylindrical or rectangular shell wall 30 and a generally circular or rectangular end wall 32. A stator 40 and laminations 42 have stator windings 41 (formed from enameled copper wire), wherein the stator 40 is located within the housing 22 so that a generally uniform circumferential gap or spacing 48 is provided between a generally cylindrical outer surface 44 of the stator 40 and a generally cylindrical inner surface 24 of the housing 22. A cover or end plate 36 is secured to the housing 22 over the opening of the "open can" shape, wherein the end plate 36 has a hole and a bearing 34 to support one end of a shaft 28 that carries a rotor 60. Blind holes and bearings 34 are also formed in the end wall 32 for supporting the other end of the rotor shaft 28. In the "corner" is found the rotor 60 is located. Figure 3 39, where the shell wall 30 intersects the end wall 32 and the shell wall 30 intersects the end plate 36. In this first variation, the polymer 50 fills the circumferential gap 48 just outside the stator 40, but does not extend into the corner area / void / pocket 39.

[0073] exist Figure 4 In the second variation shown, the polymer 50 extends into and fills some or all of the corner regions 39 such that little or no empty voids or pockets are filled. Figure 5In the third variant shown, the housing 22 has a circumferential shell wall 30 that is integral with the shell wall 30 but has no end wall 32 and has two opposing covers or end plates 36, 38, as shown, which are fastened to the shell wall 30. The polymer 50 can fill the gap 48 outside the stator 40, as shown here (and similarly as Figure 3 shown), or, similar to Figure 4 the second variant, the polymer 50 can optionally extend into the corner region 39.

[0074] The electric motor assembly 20 can include a rotor 60 that is operably disposed within a generally cylindrical internal stator cavity 47 within the stator 40. Figure 6 In Figure 3 a disassembled cross-sectional view of the first variant, the rotor 60 is shown. It can be seen here that the rotor 60 (e.g., the rotor winding) is formed around a shaft 28 having a rotational axis 29. The ends of the shaft 28 that support the rotor 60 are inserted into the generally cylindrical internal stator cavity 47 within the stator 40, and the stator 40 is received within the housing 22. After arranging the polymer 50 to fill the gap 48 as needed, the cover or end plate 36 can be fastened to the housing 22, and the other end of the shaft 28 can extend through a bearing hole in the end plate 36. This arrangement can be configured such that the polymer layer 50 effectively prevents the stator 40 from rotating relative to the housing 22, including during operation of the electric motor assembly 20.

[0075] Figure 9 A schematic cross-sectional view showing a portion of the electric motor assembly 20 is shown, which illustrates its mechanical characteristics. Here, the polymer layer 50 is shown as being sandwiched between the stator 40 or the laminations 42 and the housing 22. The stator 40 or the laminations 42 can be regarded as springs K40, 42, the polymer 50 can be modeled as springs K50 and a damper D50 arranged in parallel, and the housing 22 can be regarded as a spring K22. (It should be noted that K40, 42 can also include the copper wire 17 and the enamel coating 18 of the stator winding.) This arrangement of elements represents a mechanical spring-damper system that has its own resonance frequency, harmonic nodes, and other mechanical system characteristics. This means that the polymer 50 can be selected from specific materials such that the effective spring stiffness K50 and the damping coefficient D50 of the polymer can complement or compensate for the mechanical characteristics of the entire stator-housing combination 40, 22. For example, the polymer 50 material can be selected to minimize or mitigate certain mechanical noises or vibrations caused or contributed to by the stator 40 and / or the housing 22. Therefore, using the polymer 50 (instead of the conventional tabs 14, mounting points 13, and fasteners) to fasten the stator 40 and the housing 22 together provides a way to mechanically tune the electric motor assembly 20, which is not achievable using conventional fastening methods.

[0076] Figure 13A schematic cross-sectional view showing a portion of the motor assembly 20 is presented, which depicts its electrical characteristics. The circuit shown here is similar to Figure 7 the circuit shown, except that, as shown, the polymer layer 50 increases the resistance R50 and the capacitance C50. Similar to Figure 9 the mechanical system shown, Figure 13 the electrical system shown means that the polymer 50 can be made of a material with electrical properties that can adjust the electrical filtering efficiency of the motor assembly 20, thereby minimizing or reducing electrical noise and interference.

[0077] Figures 10 - 12 A schematic cross-sectional view showing a portion of the motor assembly 20 is presented. The motor assembly 20 includes an arcuate metal strip 70 that is circumferentially arranged within the polymer layer 50 in various configurations. The strip 70 can extend around the entire circumference within the gap 48 or only around a portion of the circumference. The arcuate metal strip 70 provides stiffness and mass, which can be adjusted to act as a shock absorber for one or more resonant frequencies. The size and dimensions of the arcuate metal strip 70 can be arranged to be assembled within the gap 48 as needed and can be configured in a flat shape configuration 72 or a wavy configuration 74.

[0078] In the flat shape configuration 72 ( Figure 10 ), the arcuate metal strip 70 is spaced apart from both the outer surface 44 of the stator 40 and the inner surface 24 of the housing 22. This essentially divides the polymer layer 50 into two thinner polymer layers 52, which can have the same thickness as each other or they can have different thicknesses. The sandwich structure formed by the two thinner polymer layers 52 and the arcuate metal strip 70 is shown as a mechanical system below Figure 10 the cross-sectional view. Here, each thinner polymer layer 52 acts as a spring K52 and a damper D52, while the strip 70 acts as a mass M, and together they form a specific spring-mass-damper system as shown.

[0079] In the wavy configuration 74 ( Figures 11 - 12 ), the arcuate metal strip 70 has a non-linear wavy or contoured shape, where the first peak 76 faces the inner surface 24 of the housing 22 and the second peak 78 faces the outer surface 44 of the stator 40. The peaks 76, 78 can be smoothly rounded, or sharp, or (as Figures 11 - 12 shown) can have a flat ridge surface 79. The peaks 76, 78 can be arranged to contact one or both of the stator 40 and the housing 22, or they can both not contact it. For example, as Figure 11As shown, the first peak 76 contacts the housing 22, while the second peak 78 contacts the stator 40. In the wavy configuration 74, the arcuate metal strip 70 can be integral with the outer peripheral edge 43 of one of the laminations 42. The strip 70 can extend longitudinally within the gap 48 (i.e., in a direction parallel to the axis of rotation 29), and can take the form of a circumferential arcuate sheet.

[0080] In Figure 11 the waveform configuration 74, the arcuate metal strip 70 divides the polymer layer 50 into a plurality of generally triangular or trapezoidal sections 54. The zigzag arrangement formed by these sections 54 and the arcuate metal strip 70 is shown below in a cross-sectional view of Figure 11 a mechanical system. Here, the sections 54 act as springs K54 and dampers D54, while the strip 70 acts as a spring K70 and a mass M, which together form the specific spring-mass-damper system shown.

[0081] Figure 12 A variant of the wavy configuration 74 is shown, in which the arcuate metal strip 70 is integral with one of the laminations 42. That is, the lamination 42 and the strip 70 are formed by stamping the same metal, and the second peak 78 and the adjacent ridge surface 79 are integrally formed with the outer peripheral edge 43 of the lamination.

[0082] Figure 14 A schematic cross-sectional view of a portion of the motor assembly 20 is shown, in which the housing 22 has a plurality of protrusions 80, each of which extends inwardly from the generally cylindrical inner surface 24, and the stator 40 has a plurality of ridges 82, each of which extends outwardly from the generally cylindrical outer surface 44. The size, shape, and arrangement of these protrusions 80 and ridges 82 can be arranged to interleave with each other in an interleaved arrangement 84. This interleaved arrangement 84 can be used together with the polymer 50 for mechanical interlocking and as an additional torque retention / torque transfer feature between the stator 40 and the housing 22. As in the other configurations and arrangements discussed above, the polymer layer 50 can also be used in the interleaved arrangement 84 to provide additional damping and reduce stator vibration.

[0083] Optionally, a network 94 of cooling channels 96 can be formed in the polymer layer 50 by first forming a network 90 of sacrificial elements 92 made of a sacrificial material on the generally cylindrical outer surface 44 of the stator 40, and then removing the sacrificial material after the polymer 50 has cured. A coolant (such as antifreeze, automatic transmission fluid, oil, etc.) can be circulated through these channels 96 to cool the motor assembly 20 during operation. The process of forming the network 94 of cooling channels 96 is discussed in more detail below.

[0084] According to another embodiment, the electric motor assembly 20 includes: (i) a metal housing 22 having a generally cylindrical inner surface 24 that defines a generally cylindrical cavity 26 within the housing 22; (ii) a stator 40 operatively disposed within the generally cylindrical cavity 26, the stator 40 including a plurality of stacked metal laminations 42, wherein each lamination 42 has an outer peripheral edge 43 and a plurality of finger-like elements 45 extending inwardly toward the center of the lamination 42, wherein a gap 48 having a generally cylindrical shell shape 49 is defined between the stator 40 and the housing 22 and no lamination 42 is directly connected to the housing 22; and (iii) a polymer layer 50 substantially filling the gap 48 such that the stator 40 is fastened to the housing 22 only by the polymer 50. In this embodiment, the polymer 50 has material properties that provide a predetermined electrical filtering of electrical noise between the stator 40 and the housing 22.

[0085] In this embodiment, the electric motor assembly 20 may further include a rotor 60 operatively disposed within the generally cylindrical inner stator cavity 47, wherein the polymer layer 50 effectively prevents the stator 40 from rotating relative to the housing 22 during operation of the electric motor assembly 20. The electric motor assembly 20 may further include an arcuate metal strip 70 circumferentially disposed within the polymer layer 50, wherein the arcuate metal strip 70 may be configured in one of the following configurations: (i) a flat shape configuration 72, wherein the arcuate metal strip 70 is spaced apart from both the stator 40 and the housing 22, and (ii) a wavy configuration 74, wherein the arcuate metal strip 70 is arranged to contact both the stator 40 and the housing 22, contact one of the stator 40 and the housing 22, or not contact either the stator 40 or the housing 22.

[0086] Figure 15 A flowchart is shown that illustrates a first method 100 of manufacturing the electric motor assembly 20 as described herein. The method 100 includes a series of steps represented by numbered boxes in the flowchart. At step 140, the stator 40 is disposed within the housing 22 such that a gap 48 is defined between the stator 40 and the housing 22 and such that the stator 40 is not directly connected to the housing 22. Then at step 160, the gap 48 is substantially filled with the polymer 50, enabling the stator 40 to be fastened to the housing 22 only by using the polymer 50. The method 100 may further include, at step 180, curing the polymer 50 such that the stator 40 is fastened to the housing 22 only by the polymer 50. In this embodiment, the polymer 50 may have material properties that provide a predetermined electrical filtering of electrical noise between the stator 40 and the housing 22 when the polymer 50 is cured.

[0087] Method 100 may further include inserting an arcuate metal strip 70 within the gap 48 at any one of steps 110, 130, 150, or 170, where the arcuate metal strip 70 may be configured in one of the following configurations: (i) a flat shape configuration 72, where the arcuate metal strip 70 is spaced apart from both the stator 40 and the housing 22, and (ii) a wavy configuration 74, where the arcuate metal strip 70 is arranged to contact both the stator 40 and the housing 22, contact one of the stator 40 and the housing 22, or not contact either the stator 40 or the housing 22. (Note that the blocks for steps 110, 130, 150, and 170 are shown in dashed lines; this indicates that the optional step of inserting the arcuate metal strip 70 may be performed at any of these points in method 100.)

[0088] Method 100 may also include, at step 120, forming a first network 90 of sacrificial elements 92 made of a sacrificial material on the generally cylindrical outer surface 44 of the stator 40, and at step 190, removing the sacrificial material (e.g., by etching, deflagration, etc.) after the polymer 50 has cured to form a second network 94 of cooling channels 96 on the generally cylindrical outer surface 44 of the stator 40. The size, shape, and arrangement of the sacrificial elements 92 may be arranged as interconnected tubes, flow channels, manifolds, etc., including inlets and outlets, which may include fluid connectors or couplings or dock with fluid connectors or couplings. Note that in step 120, the first network 90 is filled with the sacrificial material, and when the sacrificial material is removed in step 190, the space occupied by the resulting second network 94 is substantially the same as the space previously occupied by the first network 90. The sacrificial material may be any material that can be arranged or deposited on the outer surface 44 to form the first network 90 of sacrificial elements 92 and that can withstand the pressure of the polymer 50 disposed within the gap 48 without disturbing the first network 90 of sacrificial elements 92 (e.g., by injecting the polymer 50 into the gap 48). The sacrificial material should also be chemically compatible with the polymer 50, and the chemicals (e.g., etchant) or processes (e.g., deflagration) used to remove the sacrificial material should also be chemically and otherwise compatible with the polymer 50.

[0089] Figures 17 - 20 Illustrated are the sequential process steps for forming cooling channels 96 within the electric motor assembly 20 in accordance with the first method 100. First, Figure 17 Illustrated is step 120, where a first network 90 of sacrificial elements 92 is formed on the generally cylindrical outer surface 44 of the stator 40. Second, Figure 18Step 140 is illustrated, in which the stator 40 is placed within the housing 22 such that the generally cylindrical outer surface 44 of the stator 40 is spaced apart from the generally cylindrical inner surface 24 of the housing 22 by a gap 48, and the stator 40 is not directly connected to the housing 22. In this step, the sacrificial element 92 is disposed within the gap 48. Third, Figure 19 Step 160 is shown, in which the gap 48 is substantially filled with a polymer 50 (such as by injection). Fourth, Figure 20 Step 190 is shown, in which after curing the polymer 50, the sacrificial material is removed to form a second network 94 of cooling channels 96 on the outer surface 44 of the stator 40.

[0090] Figure 16 A flow chart is shown that illustrates a second method 200 of manufacturing the motor assembly 20 as described herein. This second method 200 has some similarities with the first method 100 described above, but also some differences. At step 240, the stator 40 is coated with a polymer 50, such as by dipping the stator 40 into a container of liquid (e.g., uncured) polymer 50, and at step 260, the coated stator 40 is placed within the housing 22 such that a gap 48 is defined between the stator 40 and the housing 22, and the stator 40 is not directly connected to the housing 22. Optionally, steps 240 and 260 can be combined, such as by first placing the liquid polymer 50 within the upturned housing 22 (such that the internal cavity 26 of the housing serves as a container for the liquid polymer 50), and then inserting the stator 40 into the cavity 26, thereby coating the stator 40 with the polymer 50 and placing the stator 40 within the cavity 26. In any case, the gap 48 between the stator 40 and the housing 22 is substantially filled with the polymer 50, where the polymer 50 is capable of securing the stator 40 to the housing 22 in a cured state using only the polymer 50. Method 200 can further include, at step 280, curing the polymer 50 such that the stator 40 is secured to the housing 22 only by the polymer 50. In this embodiment, the polymer 50 can have material properties that provide a predetermined electrical filtering of electrical noise between the stator 40 and the housing 22 when the polymer 50 is cured.

[0091] Similar to the first method 100, the second method 200 may further include, at any one of steps 210, 230, 250, or 270, inserting an arcuate metal strip 70 within the gap 48, wherein the arcuate metal strip 70 may be configured in one of the following configurations: (i) a flat shape configuration 72, wherein the arcuate metal strip 70 is spaced apart from both the stator 40 and the housing 22, and (ii) a wavy configuration 74, wherein the arcuate metal strip 70 is arranged to contact both the stator 40 and the housing 22, contact one of the stator 40 and the housing 22, or not contact either the stator 40 or the housing 22. (The boxes for steps 210, 230, 250, and 270 are shown in dashed lines to indicate that the optional step of inserting the arcuate metal strip 70 may be performed at any of these points in method 200.)

[0092] The method 200 may also include, at step 220, forming a first network 90 of sacrificial elements 92 made of a sacrificial material on the generally cylindrical outer surface 44 of the stator 40, and at step 290, removing the sacrificial material after the polymer 50 has cured to form a second network 94 of cooling channels 96 on the generally cylindrical outer surface 44 of the stator 40. Figure 17 、 19 Figures 19 and 20 illustrate the successive process steps for forming the cooling channels 96 within the electric motor assembly 20 according to the second method 200. First, Figure 17 Figure 19 illustrates step 220, wherein a first network 90 of sacrificial elements 92 is formed on the generally cylindrical outer surface 44 of the stator 40. Second, Figure 19 Figure 20 illustrates step 260, wherein the stator 40 is disposed within the housing 22 such that a gap 48 is defined between the stator 40 and the housing 22, and the stator 40 is not directly connected to the housing 22. Third, Figure 20 Figure 20 illustrates step 290, wherein the sacrificial material is removed after the polymer 50 has cured to form a second network 94 of cooling channels 96 on the outer surface 44 of the stator 40.

[0093] The foregoing description is intended to be illustrative, not restrictive. While the dimensions and types of the materials described herein are intended to be illustrative, they are in no way meant to be restrictive and are only exemplary embodiments. In the appended claims, the use of terms such as “first,” “second,” “top,” “bottom,” etc. is used only as labels and is not intended to impose numerical or positional requirements on their objects. As used herein, an element or step recited in the singular and preceded by the word “a” or “an” should be understood to not exclude a plurality of such elements or steps, unless expressly stated to the contrary. Additionally, the phrases “at least one of A and B” and “A and / or B” should be understood to mean “only A, only B, or both A and B,” respectively. Further, unless expressly stated to the contrary, an embodiment that includes one element or multiple elements having a particular characteristic may include other such elements that do not have that characteristic. When broad adverbs such as “substantially” and “approximately” are used herein to modify an adjective, these adverbs mean “to a great degree of importance” and / or “to a large extent,” and do not necessarily mean “completely,” “fully,” “strictly,” or “thoroughly.” Additionally, the word “adjacent” may be used herein to describe the position of an object or a part thereof relative to another object or a part thereof, and / or to describe the positional relationship between two objects or their respective parts relative to each other, and may mean “close to,” “adjacent to,” “near,” “bring close to,” “at,” etc.

[0094] According to the present disclosure, the written description uses examples, including the best mode, to enable one of ordinary skill in the art to make and use the devices, systems, and compositions of matter, and to perform the methods. The appended claims, including their equivalents, define the scope of the present disclosure.

Claims

1. A motor assembly, comprising: A housing having a generally cylindrical inner surface that defines a generally cylindrical cavity within the housing; A stator operably disposed within the generally cylindrical cavity, the stator including a plurality of stacked laminations, wherein each lamination has an outer peripheral edge and a plurality of finger-like elements extending inwardly toward the center of the lamination; and A polymer layer disposed between the generally cylindrical outer surface of the stator and the generally cylindrical inner surface of the housing such that the stator is bonded to the housing by the polymer layer, An arcuate metal strip circumferentially disposed within the polymer layer, wherein the arcuate metal strip is configured in a wavy configuration, and wherein the arcuate metal strip is arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator or the housing, Wherein, in the wavy configuration, the arcuate metal strip is integral with the outer peripheral edge of one of the laminations.

2. The motor assembly according to claim 1, wherein, A gap having a generally cylindrical housing shape is defined between the stator and the housing, and wherein the polymer layer substantially fills the gap.

3. The motor assembly according to claim 1, wherein, None of the laminations are directly connected to the housing.

4. The motor assembly according to claim 1, wherein, The stator is not directly connected to the housing.

5. The motor assembly according to claim 1, wherein, The stator is fastened to the housing only by the polymer layer.

6. The motor assembly according to claim 1, further comprising: A rotor operably disposed within a generally cylindrical inner stator cavity.

7. The motor assembly according to claim 1, wherein, The polymer layer effectively prevents rotation of the stator relative to the housing.

8. The motor assembly according to claim 1, wherein, The polymer layer has material properties that provide a predetermined electrical filtering of electrical noise between the stator and the housing.

9. The motor assembly according to claim 1, wherein, The housing includes a plurality of protrusions, each protrusion extending inwardly from the generally cylindrical inner surface, and the stator includes a plurality of ridges, each ridge extending outwardly from the generally cylindrical outer surface, wherein the protrusions and the ridges are interleaved with each other.

10. The motor assembly according to claim 1, wherein, A network of cooling channels is formed in the polymer layer by forming a network of sacrificial elements made of a sacrificial material on the cylindrical outer surface of the stator and then removing the sacrificial material after the polymer layer has cured.

11. A motor assembly, comprising: A metal housing having a generally cylindrical inner surface that defines a generally cylindrical cavity within the housing; A stator operably disposed within the generally cylindrical cavity, the stator including a plurality of stacked metal laminations, wherein each lamination has an outer peripheral edge and a plurality of finger-like elements extending inwardly toward the center of the lamination, wherein a gap having a generally cylindrical housing shape is defined between the stator and the housing, and none of the laminations are directly connected to the housing; and A polymer layer substantially filling the gap disposed between the outer cylindrical surface of the stator and the inner cylindrical surface of the housing such that the stator is fastened to the housing only by the polymer layer; and Wherein, the polymer layer has material properties that provide a predetermined electrical filtering of electrical noise between the stator and the housing. Bow-shaped metal strips circumferentially arranged within the polymer layer, wherein the bow-shaped metal strips are configured in a wavy configuration, and wherein the bow-shaped metal strips are arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator or the housing. Wherein, in the wavy configuration, the bow-shaped metal strips are integral with the outer peripheral edge of one of the laminations.

12. The motor assembly according to claim 11, further comprising: A rotor operably disposed within a generally cylindrical inner stator cavity, wherein the polymer layer effectively prevents rotation of the stator relative to the housing during operation of the motor assembly.

13. A method of manufacturing a motor assembly, comprising: Disposing a stator within a housing such that a gap is defined between the stator and the housing, and the stator is not directly connected to the housing; And Substantially filling the gap with a polymer layer capable of fastening the stator to the housing only through the polymer layer. Inserting bow-shaped metal strips into the gap, wherein the bow-shaped metal strips are configured in a wavy configuration, and wherein the bow-shaped metal strips are arranged to contact both the stator and the housing, contact one of the stator and the housing, or not contact either the stator or the housing. Wherein, in the wavy configuration, the bow-shaped metal strips are integral with the outer peripheral edge of one of the laminations.

14. The method according to claim 13, further comprising: Curing the polymer layer such that the stator is fastened to the housing only through the polymer layer.

15. The method according to claim 13, wherein, The polymer layer has the following material properties: when the polymer layer is cured, the material properties provide a predetermined electrical filtering of electrical noise between the stator and the housing.

16. The method according to claim 14, further comprising: Forming a network of sacrificial elements made of a sacrificial material on a generally cylindrical outer surface of the stator; And Removing the sacrificial material after the polymer layer is cured to form a network of cooling channels on the generally cylindrical outer surface of the stator.

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