Electric motor having stator with laminations configured to form unique cooling channels

Abstract

The present disclosure relates to an electric motor having a stator with laminations configured to form unique cooling channels, in particular, an electric motor having a stator formed from a plurality of laminations. Each of the laminations has a radially inner lamination edge and a radially outer lamination edge, the radially inner lamination edge bordering a rotor bore configured to receive a rotor therein. Each of the laminations has a plurality of cooling holes formed therethrough. A cooling hole formed in a given one of the laminations is disposed radially between the radially outer lamination edge and the radially inner lamination edge. Each of the laminations is sealingly coupled to at least one other lamination. Each cooling hole in the laminations forms part of a unique cooling channel extending along the axial length of the stator. At least a portion of the cooling holes in each of the cooling channels are circumferentially staggered about a motor axis of the electric motor.

Description

[0001] This application is a divisional application of an invention patent application with an application date of November 7, 2018, application number 201811317949.9, and invention name “Electric motor having a stator with laminated sheets configured to form unique cooling channels”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 593,419, filed on December 1, 2017, the disclosure of which is incorporated by reference as if fully set forth herein in detail. Technical Field

[0004] The present disclosure relates to an electric motor having a stator with laminations configured to form distinct cooling channels. Background Art

[0005] This section provides background information related to the present disclosure which is not necessarily prior art.

[0006] Electric motors are increasingly used in applications such as vehicle propulsion, where performance requirements on the electric motors as well as size, mass and cost constraints require that the electric motors be actively cooled during their operation. To further improve the performance of the electric motors and / or reduce the size, mass and / or cost of the electric motors, more efficient cooling of the electric motors is desired. Summary of the invention

[0007] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0008] In one form, the present disclosure provides an electric motor including a stator and a rotor, the stator being formed of a plurality of laminations. The rotor is received in the stator and is rotatable relative to the stator about a motor axis. Each of the laminations has a radially inner lamination edge and a radially outer lamination edge, the radially inner lamination edge being bordered by a rotor hole in which the rotor is received. Each of the laminations has a plurality of cooling holes formed therethrough. The cooling holes formed in a given one of the laminations are radially disposed between the radially outer lamination edge and the radially inner lamination edge. Each of the laminations is sealingly coupled to at least one other lamination. Each cooling hole in the laminations forms a portion of a unique cooling channel extending along the axial length of the stator. At least a portion of the cooling holes in each of the cooling channels are circumferentially staggered about the motor axis.

[0009] Further areas of applicability will become apparent from the description provided herein.The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0011] Figure 1 is a perspective view of an exemplary electric motor constructed in accordance with the teachings of the present disclosure;

[0012] Figure 2 yes Figure 1 An exploded perspective view of an electric motor;

[0013] Figure 3 It is shown Figure 1 An elevation view of a lamination stack of a stator of an electric motor;

[0014] Figure 4 It is a description of the composition Figure 1 A partially cutaway perspective view of the presence of cooling channels formed by laminations of a stator of an electric motor;

[0015] FIG. 5A to FIG. 5E It is used to form Figure 1 An elevation view of five unique laminations of a stator of an electric motor of; and

[0016] Figure 6 and Figure 7 is an elevation view of two unique laminations formed from unique lamination segments.

[0017] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0018] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0019] Reference Figure 1 and Figure 2 , an exemplary electric motor constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 10. Electric motor 10 includes a stator 12 and a rotor 14, and may be, for example, any type of electric motor, such as a brushless DC electric motor, or a type of AC induction motor, such as an asynchronous AC induction motor. Rotor 14 is received in a rotor bore 16 formed in stator 12 and is rotatable relative to stator 12 about a motor axis 18. Stator 12 may be formed of a plurality of laminations 20.

[0020] Reference Figure 3 and Figure 4, each lamination 20 may have a radially inner lamination edge 22 and a radially outer lamination edge 24, the radially inner lamination edge 22 forming a boundary or edge of the rotor bore 16. Each lamination 20 has a plurality of cooling holes 26 formed therethrough. The cooling holes 26 may be formed radially between the radially outer lamination edge 24 and the radially inner lamination edge 22. Each cooling hole in the lamination forms a portion of a unique cooling channel 30 extending along the axial length of the stator 12. The cooling channel 30 is configured to receive a cooling fluid therethrough during operation of the electric motor 10, thereby cooling the stator 12. At least a portion of the cooling holes 26 in each cooling channel 30 may be circumferentially staggered about the motor axis 18 so that the coolant flowing through each cooling channel 30 travels circumferentially through at least a portion of the stator 12 as the coolant in the cooling channel 30 passes axially through the stator 12.

[0021] Reference FIG. 5A to FIG. 5E One means for achieving circumferential offsets in the cooling passages 30 is to employ a plurality of unique laminations, such as laminations 20a, 20b, 20c, 20d, and 20e. The laminations 20a, 20b, 20c, 20d, and 20e may be identical except for the circumferential positioning of the cooling holes 26 relative to the common baseline 40. It should be appreciated that the cooling holes 26 in the laminations 20a, 20b, 20c, 20d, and 20e may be circumferentially offset to the extent that the cooling holes 26 in one lamination (such as lamination 20e) partially overlap the cooling holes 26 in the adjacent laminations (such as laminations 20d and 20a), but the cooling holes 26 in the adjacent laminations (e.g., laminations 20d and 20a) do not overlap each other or overlap each other to a substantially lesser extent.

[0022] Although Figure 4 and Figure 5A-5EThe example shown in the embodiment of the present invention employs five discrete laminations 20a, 20b, 20c, 20d and 20e arranged in a repeating sequence, wherein each lamination is disposed between two laminations of different configurations, but it should be appreciated that a greater or lesser number of discrete laminations may be employed instead. In addition, the laminations may be arranged in various other ways. For example, the laminations may be arranged in a sequence consisting of identical lamination portions arranged adjacent to each other. For example, the repeating sequence may include five of each of 20a, 20b, 20c, 20d and 20e (i.e., a stack of five laminates 20b is adjacent to a stack of five laminates 20a and a stack of five laminates 20c on opposite sides, and a stack of five laminates 20d is adjacent to a stack of five laminates 20e and a stack of five laminates 20c on opposite sides of ends opposite to the stack of five laminates 20b), so that the sequence of laminates consists of 20a, 20a, 20a, 20a, 20b, 20b, 20b, 20b, 20b, 20c, 20c, 20c, 20c, 20d, 20d, 20d, 20d, 20e, 20e, 20e, 20e and 20e. By stacking discrete / distinct laminations in a desired manner (eg, in a sequentially arranged stack), surface area and path length can be balanced for a desired heat transfer rate and pressure drop.

[0023] exist Figure 2 and Figure 4 In the embodiment, each of the laminations 20 can be formed of a suitable material, such as steel. If desired, each lamination 20 can be formed with a preferred orientation magnetic property in a manner known in the art.

[0024] Each lamination 20 may be sealingly coupled to at least one other lamination 20. For example, the laminations 20 may be adhesively bonded to one another. The adhesive that secures the laminations 20 to one another may penetrate between adjacent laminations 20 onto the edges of the cooling holes 26 in an amount that covers the edges but does not close any cooling holes 26. Configuration in this manner may provide additional strength to the bond between adjacent laminations 20, and / or provide a non-reactive barrier between the material of the laminations 20 (i.e., steel in the example provided) and the coolant intended to flow through the coolant passages 30.

[0025] Reference Figure 6 and Figure 7 Each lamination may be formed from a plurality of lamination segments 50. In the particular example provided, each of the distinct laminations (e.g., Figure 6 The laminate 20a or Figure 7 The lamination 20c) in the embodiment is composed of a plurality of identical lamination segments ( Figure 6 The stacked segment 50a or Figure 7The stack of stacked laminations 20 may be formed of a plurality of identical stacked laminations 50a (i.e., stacked laminations 50a are used only in the formation of stacked laminations 20a, and stacked laminations 50c are used only in the formation of stacked laminations 20c). Each stacked lamination 50 may have a radially inner segment edge 22-1, a radially outer segment edge 24-1, and a pair of circumferential segment edges 60, the radially inner segment edge 22-1 forming a portion of the radially inner lamination edge 22 of an associated one of the stacked laminations 20, the radially outer segment edge 24-1 forming a portion of the radially outer lamination edge 24 of an associated one of the stacked laminations 20, and the pair of circumferential segment edges 60 each configured to abut a corresponding circumferential segment edge 60 of an associated adjacent stacked lamination 50. A portion of the cooling hole 26 in each stacked lamination 20 may be formed in each of the stacked laminations 50 that make up the stacked laminations 20.

[0026] The circumferential segment edges 60 may be formed in any desired manner / shape, but preferably do not extend through any cooling holes 26. Optionally, the circumferential segment edges 60 of the lamination segments 60 in a given lamination 20 may be configured to interlock the circumferential segment edges 60 of adjacent lamination segments 50 within the given lamination 20. For example, a first circumferential segment edge 60a on a given one of the lamination segments 50 may form a tab, while a second circumferential segment edge 60b on the given one of the lamination segments 50 may form a tab hole. The tab hole may be configured to receive a tab on a first circumferential segment edge 60a on a circumferentially adjacent lamination segment 50 therein.

[0027] The above description of the embodiment is provided for the purpose of illustration and description. It is not intended to be exhaustive or limit the present disclosure. Even if not specifically shown or described, the individual elements or features of a particular embodiment are generally not limited to the particular embodiment, but are interchangeable where applicable and can be used in the selected embodiment. It can also be changed in many ways. Such changes are not considered to be deviations from the present disclosure, and all such modifications are intended to be included in the scope of the present disclosure.

Claims

1. An electric motor comprising: a stator formed from a plurality of laminations; as well as a rotor received in the stator and rotatable relative to the stator about a motor axis; wherein each of the laminations has a radially inner lamination edge and a radially outer lamination edge, the radially inner lamination edge bordering a rotor bore in which the rotor is received, each of the laminations having a plurality of cooling holes formed therethrough, the cooling holes being formed radially between the radially outer lamination edge and the radially inner lamination edge, each of the laminations being sealingly coupled to at least one other lamination; and wherein each cooling aperture in each of said laminations forms a portion of a unique cooling channel extending along an axial length of said stator, and wherein at least a portion of said cooling apertures in each of said cooling channels are circumferentially staggered about said motor axis; wherein each of the laminations comprises a plurality of lamination segments, each of the lamination segments having a radially inner segment edge, a radially outer segment edge, and a pair of circumferential segment edges, the radially inner segment edge forming a portion of the radially inner lamination edge of an associated one of the laminations, the radially outer segment edge forming a portion of the radially outer lamination edge of an associated one of the laminations, the pair of circumferential segment edges each being configured to abut a respective circumferential segment edge of an associated adjacent lamination segment, wherein a portion of the cooling hole is formed in each of the lamination segments; wherein at least five unique and different lamination segments are used to form each cooling channel over the axial length of the stator, and The plurality of laminations are arranged in a repeating sequence, wherein the cooling holes in adjacent laminations partially overlap each other in the repeating sequence, and adjacent laminations in the repeating sequence are configured differently.

2. The electric motor of claim 1, wherein the lamination segments constituting a given one of the laminations are identical.

3. The electric motor of claim 1 , wherein a first one of the circumferential segment edges on a given one of the stack segments forms a protrusion, and a second one of the circumferential segment edges on a given one of the stack segments forms a protrusion hole, wherein the protrusion hole is configured to receive the protrusion on the first one of the circumferential segment edges on a circumferentially adjacent stack segment therein. 4 . The electric motor of claim 3 , wherein the circumferential segment edge of any of the lamination segments does not penetrate any of the cooling holes.

5. The electric motor of claim 1 wherein each of said lamination segments is formed to have preferentially oriented magnetic properties.

6. An electric motor comprising: a stator formed from a plurality of laminations; as well as a rotor received in the stator and rotatable relative to the stator about a motor axis; wherein each of the laminations has a radially inner lamination edge and a radially outer lamination edge, the radially inner lamination edge bordering a rotor bore in which the rotor is received, each of the laminations having a plurality of cooling holes formed therethrough, the cooling holes being formed radially between the radially outer lamination edge and the radially inner lamination edge, each of the laminations being sealingly coupled to at least one other lamination; and wherein each cooling aperture in each of said laminations forms a portion of a unique cooling channel extending along an axial length of said stator, and wherein at least a portion of said cooling apertures in each of said cooling channels are circumferentially staggered about said motor axis; wherein at least five unique and different laminations are used over the axial length of the stator to form each cooling channel, and The plurality of laminations are arranged in a repeating sequence, wherein the cooling holes in adjacent laminations partially overlap each other in the repeating sequence, and adjacent laminations in the repeating sequence are configured differently.

7. The electric motor of claim 6 wherein each of said laminations is formed to have preferentially oriented magnetic properties.

8. An electric motor comprising: a stator formed from a plurality of sets of laminations, each set of laminations being formed from a plurality of unique laminations; as well as a rotor received in the stator and rotatable relative to the stator about a motor axis; wherein each of the plurality of unique laminations has a radially inner lamination edge and a radially outer lamination edge, the radially inner lamination edge bordering a rotor bore in which the rotor is received, each of the laminations having a plurality of cooling holes formed therethrough, the cooling holes being formed radially between the radially outer lamination edge and the radially inner lamination edge, each of the plurality of unique laminations being sealingly coupled to at least one other of the plurality of unique laminations; wherein a plurality of separate cooling channels are formed in the stator, each of the separate cooling channels extending helically around the motor axis along an axial length of the stator; wherein each cooling aperture in one of the plurality of distinct laminations forms a portion of an associated one of the separate cooling channels; and Each of the separate cooling channels is adapted to convey a flow of cooling fluid helically about the motor axis through the plurality of laminations without merging the flows of cooling fluid from two or more of the separate cooling channels within the plurality of laminations.

9. The electric motor of claim 8 wherein each of the plurality of unique laminations comprises a plurality of lamination segments, each of the lamination segments having a radially inner segment edge, a radially outer segment edge, and a pair of circumferential segment edges, the radially inner segment edge forming a portion of the radially inner lamination edge of an associated one of the plurality of unique laminations, the radially outer segment edge forming a portion of the radially outer lamination edge of an associated one of the plurality of unique laminations, the pair of circumferential segment edges each being configured to abut a respective circumferential segment edge of an associated adjacent lamination segment, wherein a portion of the cooling hole is formed in each of the lamination segments.

10. The electric motor of claim 9, wherein a first one of the circumferential segment edges on a given one of the stack segments forms a protrusion, and a second one of the circumferential segment edges on another one of the stack segments forms a protrusion hole, the protrusion hole being configured to receive the protrusion on the first one of the circumferential segment edges on a circumferentially adjacent stack segment therein. 11 . The electric motor of claim 10 , wherein the circumferential segment edge of any of the lamination segments does not penetrate any of the cooling holes.

12. The electric motor of claim 9, wherein at least five unique and distinct lamination segments are employed over the axial length of the stator to form each cooling channel.

13. The electric motor of claim 12, wherein the lamination segments comprising a given one of the plurality of unique laminations are identical.

14. The electric motor of claim 9 wherein each of said lamination segments is formed to have preferentially oriented magnetic properties.

15. The electric motor of claim 8, wherein each lamination of the plurality of unique laminations is formed to have preferentially oriented magnetic properties.

16. The electric motor of claim 8, wherein at least five unique and distinct laminations are employed across the axial length of the stator to form each cooling channel.

17. The electric motor of claim 8, wherein at least a portion of the cooling holes in each of the separate cooling channels are circumferentially staggered about the motor axis.

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