Stator winding with alternating winding pitches

Abstract

A stator for an electric motor includes a stator core having a multiphase winding thereon. The stator core has a plurality of slots formed therein and defines a first axial end and a second axial end. The multiphase winding includes a plurality of parallel paths for each winding phase, each parallel path completing multiple turns around the stator core, and each parallel path includes a series of slot segments disposed in a layer of the plurality of slots and end turns alternately connecting consecutive slot segments on the first axial end and consecutive slot segments on the second axial end. The pitch of the end turns of the slot segments connecting at least one parallel path alternates between a first pitch on the first axial end and a second pitch on the second axial end, the second pitch being different from the first pitch.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent document claims priority to U.S. Provisional Patent Application Serial No. 62 / 941,362, filed November 27, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of electric motors, and more specifically to the winding arrangement of electric motors. Background Technology

[0004] Electric motors are designed according to their intended application to meet specific operational requirements. Depending on the specific design, a motor will possess a variety of performance characteristics. Examples of design features that contribute to operational performance include stator size, rotor size, torque output, efficiency, type and arrangement of windings, number of stator slots, number of poles, number of slots per phase per pole, number of conductors per slot, number of parallel paths per phase, number of turns, and any other design parameters that a person skilled in the art will recognize.

[0005] When designing an electric motor, it is desirable to provide a motor that meets predetermined performance characteristics while also offering advantages over existing designs. For example, it would be advantageous to provide a motor with an improved winding arrangement that reduces resistance compared to previous designs. It would also be advantageous to provide a motor with a smaller size than previous designs. Furthermore, it would be advantageous to provide a motor that is easier to manufacture than previous designs.

[0006] While it is desirable to provide an electric motor that provides one or more of the aforementioned advantageous features or other advantageous features that are clear to a person reading this disclosure, the teachings disclosed herein extend to those embodiments that fall within the scope of the appended claims, regardless of whether they achieve one or more of the aforementioned advantages. Summary of the Invention

[0007] According to at least one embodiment of the present invention, a stator for an electric motor includes a stator core and a winding disposed on the stator core. The stator core has a plurality of slots formed therein and defines a first axial end and a second axial end. The winding includes slot segments disposed in layers of the plurality of slots and end turns connecting the slot segments. The winding defines a first winding path and a second winding path. The first winding path includes an outer layer end turn, an inner layer end turn, and a transition end turn located between the outer layer end turn and the inner layer end turn. The second winding path includes an outer layer end turn, an inner layer end turn, and a transition end turn located between the outer layer end turn and the inner layer end turn. The outer layer end turn of the second winding path is nested with the outer layer end turn of the first winding path, wherein the inner layer end turn of the second winding path is nested with the inner layer end turn of the first winding path.

[0008] In at least one additional embodiment of the invention, a stator for an electric motor includes a stator core on which a multiphase winding is disposed. The stator core has a plurality of slots formed therein and defines a first axial end and a second axial end. The multiphase winding includes a plurality of parallel paths for each winding phase, each parallel path completing multiple turns around the stator core, and each parallel path includes a series of slot segments disposed in a layer of the plurality of slots and end turns alternately connecting consecutive slot segments on the first axial end and consecutive slot segments on the second axial end. The pitch of the end turns of the slot segments connecting at least one parallel path alternates between a first pitch on the first axial end and a second pitch on the second axial end, the second pitch being different from the first pitch. Attached Figure Description

[0009] Figure 1 A cross-sectional view of an electric motor including a stator with winding arrangements is shown;

[0010] Figure 2 It shows Figure 1 A three-dimensional view of the stator core of the motor;

[0011] Figure 3 It shows Figure 2 A three-dimensional view of the stator core, in which the winding arrangement is located on the stator core;

[0012] Figure 4 It shows the use of Figure 1 A plan view of the winding arrangement of a motor with two conductors in one phase;

[0013] Figure 5 It shows Figure 4 A plan view of the two conductors, showing the pitch arrangement of the end turns;

[0014] Figure 6 This illustrates the nested arrangement after mounting on the stator core. Figure 5 A plan view of the two wires;

[0015] Figure 7 The diagram shows the intermediate end coil and the adjacent end coil. Figure 6 The enlarged cross-section of the conductor;

[0016] Figure 8 In addition to the additional intermediate end turns of the other two phases used for winding arrangement, it is also shown that Figure 7 The middle end coil;

[0017] Figure 9A It shows including Figures 4 to 8 A cross-sectional view of the stator with its winding arrangement;

[0018] Figure 9B yes Figure 9A An enlarged view of the upper end coil of the stator section;

[0019] Figure 10 Shown Figures 4 to 8 as well as Figure 9A and Figure 9B A cross-sectional view of a portion of the stator core and winding arrangement, showing only the conductors for one phase of the winding arrangement;

[0020] Figure 11 It is the manufacture of including Figures 3 to 10 A flowchart illustrating the method of arranging the windings of a motor;

[0021] Figure 12 It shows the use of Figures 3 to 10 A plan view of two conductors of one phase in a first alternative embodiment of the winding arrangement shown;

[0022] Figure 13 The stator core of the motor and Figure 12 A cross-sectional view of a portion of the stator core, showing only the conductors of one phase used for the winding arrangement;

[0023] Figure 14 It shows the use of Figures 3 to 10 A plan view of two conductors of one phase in a second alternative embodiment of the winding arrangement shown;

[0024] Figure 15 The stator core of the motor and Figure 14 A cross-sectional view of a portion of the stator core, showing only the conductors of one phase used for the winding arrangement;

[0025] Figure 16 It shows the use of Figures 3 to 10 A plan view of two conductors of one phase in a third alternative embodiment of the winding arrangement shown.

[0026] Figure 17 The stator core of the motor is shown. Figure 17 A cross-sectional view of a portion of the stator core, showing only the conductors for one phase of the winding arrangement; and

[0027] Figure 18 It shows including Figure 1 A block diagram of a vehicle with an electric motor. Detailed Implementation

[0028] Reference Figures 1 to 3The motor 10 includes a housing 12, within which a stator assembly 20 and a rotor assembly 14 are located. The stator assembly 20 includes a stator core 22 on which a winding arrangement 40 is located. As disclosed herein, the winding arrangement is configured to have multiple winding paths, each winding path having alternating winding pitches that allow for nesting of the motor's end turns.

[0029] motor

[0030] The rotor assembly 14 is located within the stator core 22 and mounted on a shaft 16. The shaft 16 is rotatably supported by a bearing 18. The shaft 16, in turn, supports the rotor assembly 14. The rotor assembly 14 includes a rotor hub 15 fixed relative to the shaft 16, and rotor laminations 17 fixedly mounted on the rotor hub 15 and configured to rotate relative to the stator 20. It will be appreciated that the rotor assembly can take any of many different forms depending on the type of motor. In at least one embodiment, permanent magnets (not shown) are mounted on the rotor laminations 17. In at least one alternative embodiment, electrical windings (not shown) are positioned on the rotor laminations 17. The rotor 14 and shaft 16 are configured to rotate relative to the housing 12, while the stator assembly 20 remains stationary relative to the housing 12.

[0031] The stator assembly 20 includes a stator core 22 and a winding arrangement 40. The stator core 22 comprises a ferromagnetic material and is typically formed of multiple steel plates that are stamped and stacked on top of each other to form a lamination stack. Figure 2 As best shown, the stator core 22 is generally cylindrical in shape, defined by a central axis 24, a first axial end 32, and a second axial end 34. The first axial end 32 may also be referred to herein as the “upper” end, and the second axial end 34 may be referred to herein as the “lower” end. However, it will be appreciated that the terms “upper” and “lower” as used herein are not intended to determine any particular orientation of the stator core or winding, but are merely for convenience in identifying the different ends associated with the stator core 22 shown in the figures.

[0032] Continue to refer to Figure 2 The stator core 22 also includes an inner peripheral surface 26 and an outer peripheral surface 28. A plurality of teeth 31 are formed inside the stator core 22 between the inner peripheral surface 26 and the outer peripheral surface 28. Each tooth extends radially inward and terminates on the inner peripheral surface 26. Axial grooves 30 are formed between the teeth 31 of the stator core 22. Depending on the configuration of the teeth 31, the grooves 30 can be as follows: Figure 2The slots 30 shown open along the inner circumferential surface 26 of the stator core 16, or may be semi-enclosed slots, wherein the width of each slot 30 near the inner circumferential surface 26 is smaller than the width closer to the outer circumferential surface 28. Openings to the slots 30 are configured to extend through the inner circumferential surface 26 and the two opposing ends 32 and 34 of the stator core 22. Each slot is defined by opposing radial walls, and wires or other conductors are held within the slots, as described in further detail below.

[0033] The stator core 22 is configured to hold the winding arrangement 40 (which may also be simply referred to as the "winding") within slots 30 of the stator core 22. The winding arrangement is formed by a plurality of conductors. It will be appreciated that such conductors may be constructed differently depending on the type of motor 10. In at least one embodiment, the winding arrangement 40 is formed by a plurality of elongated wires (e.g., copper wires) wound around the slots 30 of the stator core 22 to form a winding path of the winding (e.g., a single wire passing through the slot and making one or more full turns around the stator core). In at least one alternative embodiment, the winding path of the winding arrangement 40 may be formed by a plurality of segmented conductors 42.

[0034] Figure 3 A perspective view of the stator 20 is shown, in which the conductors 42 of the winding arrangement 40 are located in slots of the stator core 22. It should be understood that the conductors 42 can be arranged in the motor in any of a variety of forms. For example, the windings can be formed from elongated wires pre-shaped and inserted into slots in the stator core. Alternatively, the windings can be formed from segmented conductors (also known as “hairpin” or “U-shaped” segments) inserted into slots and joined together (e.g., by welding or other connection methods).

[0035] Each conductor 42 includes an in-slot / axial portion 43 located in a slot, and an end loop portion 44 (which may also be referred to herein as an "end coil" or "U-shaped coil") extending between the in-slot portions (also referred to herein as "slot segments"). The in-slot segments can be arranged in a single row within the laminated slot, each location defining a layer of the slot. These layers can be defined from the outer layer closest to the laminate outer diameter (OD) to the inner layer closest to the laminate inner diameter (ID). For a stator with eight conductors in a slot, the layers can be defined as follows: 1 (closest to OD), 2, 3, 4, 5, 6, 7, and 8 (closest to ID). For each path, a series of consecutive slot segments are defined, wherein the end loop portions alternately connect consecutive slot segments on a first axial end and consecutive slot segments on a second axial end. For example, a path may include: a first slot segment in a slot connected to an upper end coil; a consecutive second slot segment removing seven slots from the first slot segment and also connected to an upper end coil; and a lower end coil connected to the second slot segment. A series of slot segments—followed by upper end turns—followed by continuous slot segments—followed by lower end turns—defines a complete sinusoidal portion of the winding path.

[0036] U-shaped coil portion 44 in Figure 3 The first end of the stator 32 is clearly visible. Each U-shaped coil portion 44 extends through multiple slots on the first end 32 of the stator 20, the number of slots (plus 1) defining the end loop "pitch" of the end coil. For example, if the end coil 44 extends through 5 slots (e.g., slots #1 to #7), the end loop is defined as a 6-pitch end loop. In various embodiments, the windings can be staggered (i.e., most of the end loop connects slot segments in one layer to slot segments in another layer) or cascaded (i.e., most of the end loop connects slot segments in one layer to slot segments in the same layer). In any case, as explained in further detail below, the end coils 44 are not all identical because different pitches define different end coils 44, and / or leads or other connections may be provided within the winding arrangement 40.

[0037] Winding arrangement with alternating winding pitch

[0038] In at least one embodiment, the winding arrangement 40 is specifically configured as a winding arrangement including winding paths defining alternating winding pitches. The winding arrangement 40 is a multiphase winding arrangement, wherein each phase includes multiple winding paths, particularly multiple parallel paths. For example, the winding arrangement may be a three-phase winding arrangement (e.g., U-phase, V-phase, and W-phase), wherein each phase includes multiple winding paths connected in parallel (which may be referred to herein as "parallel paths").

[0039] In at least some embodiments, the winding arrangement 40 may have two slots per phase per pole, where the standard winding pitch (N) is equal to the number of slots per phase per pole multiplied by the number of phases. Therefore, for a stator with two slots per phase per pole and three phases, the standard pitch of the winding arrangement is equal to six (i.e., N = 2 × 3 = 6). This means, for example, that an end circuit with a standard pitch of 6 will connect the slot segment in slot #1 to the slot segment in slot #7. The pitch of an end circuit without a standard pitch will be 1 or 2 less than the standard pitch, or 1 or 2 more. Therefore, if the standard pitch is six, the pitch of an end circuit without a standard pitch can be four, five, seven, or eight.

[0040] Combination Figures 4 to 10 A first exemplary embodiment of a winding arrangement 40 with alternating winding pitches is disclosed. The winding arrangement 40 is a three-phase winding arrangement, wherein each phase includes four parallel paths and there are eight layers of conductors in each slot of the winding core. As explained in further detail herein, the stator winding has an N+1 pitch end loop at one end and an N-1 pitch end loop at the opposite end. Multiple transition end loops are also provided. Transition end loops define locations in the winding paths where changes occur, such as special end loops that generate a desired phase shift.

[0041] Now, especially referencing Figure 4 Two elongated conductors 50 and 60 are shown, each serving as one of four winding paths in a single phase (e.g., phase U) of a first exemplary embodiment of the winding arrangement 40. Elongated conductor 50 (which may be labeled "conductor A" or "winding path A" for convenience) serves as one parallel path in one phase of the winding arrangement 40, and elongated conductor 60 (which may be labeled "conductor B" or "winding path B" for convenience) serves as another parallel path in the winding arrangement 40. Each conductor 50, 60 is shown in a bent configuration before being mounted onto the stator core 22. Due to this bent configuration, each conductor 50, 60 defines an in-slot portion 43 and an end loop portion 44. More specifically, conductor A 50 defines an upper end loop 52 (for mounting on a first axial end of the stator core), an in-slot portion 53, and a lower end loop 54 (for mounting on opposite second axial ends of the stator core). Conductor A specifically includes nineteen upper end loops 52 and twenty lower end loops 54. Similarly, conductor B 60 defines an upper end loop 62 (for mounting on the first axial end of the stator core), a slot portion 63, and a lower end loop portion 64 (for mounting on the second axial end of the stator core). Conductor B also specifically includes nineteen upper end loops 62 and twenty lower end loops 64.

[0042] like Figure 4As shown, the slot portion 53 of conductor A is configured to be disposed in an odd number of layers (i.e., layers #1, #3, #5, and #7) of the stator core 22 associated with one phase (e.g., phase U) of the winding. The same applies to the slot portion 63 of conductor B. Therefore, although Figure 4 The diagram shows conductors A and B before they are mounted onto the core, but the slot portion 43 and the loop portion are configured such that after mounting onto the core 22, the slot portions 53 and 63 are located in odd-numbered layers within the slot 30 of the core. Conductors A and B are both long enough to be wound four times (i.e., four turns) around the core, with the slot portions located in layers #1, #2, #3, and #4.

[0043] Figure 5 It shows the relationship with Figure 4 The two wires shown are identical (i.e., wire A 50 and wire B 60), but... Figure 5 The different pitches of the end coils at different locations along each conductor are shown. The end coils of conductor A include an upper end coil 52 and a lower end coil 54. The upper end coil 52 of conductor A includes an outer end coil 52a (i.e., the upper end coil associated with outer layers #1 and #3), an inner end coil 52b (i.e., the upper end coil associated with inner layers #5 and #7), and a transition end coil 52c extending between the outer and inner layers (i.e., between layers #3 and #5). This transition end coil may also be referred to herein as an "intermediate end coil" because it is located between the inner and outer layers. The lower end coil 54 of conductor A includes an outer end coil 54a (i.e., the lower end coil associated with outer layers #1 and #3) and an inner end coil 54b (i.e., the lower end coil associated with inner layers #5 and #7).

[0044] like Figure 5 As shown on the left side of conductor A50, the upper set of outer end turns 52a is defined by an N+1 pitch end loop, and the lower set of outer end turns 54a is defined by an N-1 pitch end loop (where N is equal to the standard winding pitch as defined above). For example, as... Figure 5 As shown, the pitch of the upper outer layer end coil 52a of conductor A 50 in outer layers #1 and #3 is seven (i.e., 6+1), and the pitch of the upper inner layer end coil 54a in outer layers #1 and #3 is five (i.e., 6-1).

[0045] like Figure 5 As shown on the right side of the middle conductor A50, the upper set of inner layer end turns 52b is defined by an N-1 pitch end loop, and the lower set of inner layer end turns 54b is defined by an N+1 pitch end loop (where N is equal to the standard winding pitch as defined above). For example, as... Figure 5As shown, the pitch of the upper inner layer end coil 52b of conductor A 50 in inner layers #5 and #7 is five (i.e., 6-1), while the pitch of the lower inner layer end coil 54b in inner layers #5 and #7 is seven (i.e., 6+1). Therefore, it will be appreciated that the pitch of the end coils connecting the continuous slot segments along each parallel path alternates between a first pitch (e.g., upper end coil) at the first axial end and a second pitch (e.g., lower end coil) at the second axial end, the second pitch being different from the first pitch.

[0046] like Figure 5 As shown in the middle of conductor A, the upper middle end coil 52c is a phase-shifting end coil, which also has a pitch of N+1 (i.e., 6+1=7 pitch). This upper middle end coil 52c extends from layer #3 to layer #5 and serves as the point where the upper end coil 52 and the lower end coil 54 on conductor A switch their pitches. The middle end coil described herein will be considered to produce a specific phase shift similar to that described in U.S. Publication No. 2018 / 0034335 (U.S. Serial No. 15 / 652507) and U.S. Patent No. 7,034,428, the contents of which are incorporated herein by reference in their entirety. For example, these references disclose a stator having an N+1 (or N-1) pitch end loop located in the middle of the winding to cause a phase shift, which may result in a phase having a 4-8-4 (or 2-4-2) slot pattern (e.g., as described below). Figure 10 The pattern is described in further detail, wherein, for one pole, four slot segments are arranged in the left slot, eight slot segments are arranged in the middle slot, and four slot segments are arranged in the right slot.

[0047] Continue to refer to Figure 4 and Figure 5 Careful examination of conductors A 50 and B revealed that they are identical, except that conductor B 60 differs from conductor A 50 in the pitch of its end turns. In other words, conductors A and B are formally identical, but conductor B is rotated 180° relative to conductor A around the apex of the upper middle end turn 52c. Consequently, the left side of conductor A is identical to the right side of conductor B, and the right side of conductor A is identical to the left side of conductor B. Therefore, as... Figure 4 and Figure 5As shown, the upper outer layer end coil 52a of conductor A has the same pitch as the upper inner layer end coil 62b of conductor B, and the upper inner layer end coil 52b of conductor A has the same pitch as the upper outer layer end coil 62a of conductor B. Similarly, the lower outer layer end coil 54a of conductor A has the same pitch as the lower inner layer end coil 64b of conductor B, and the lower inner layer end coil 54b of conductor A has the same pitch as the lower outer layer end coil 64a of conductor B. Since conductors A and B are identical, they can be interchanged simply by rotating conductor B 180° relative to conductor A, and the manufacturing of the windings is greatly simplified because it is not necessary to manufacture two different structures to form conductors A and B.

[0048] In addition to wires A50 and B60, it will be recognized that two additional wires, wires C and D (not included in the original text), are also provided. Figures 4 to 8 as well as Figure 9A and Figure 9B As shown in the image; see also Figure 10 ), to complete Figures 4 to 10 One phase of the winding arrangement. These conductors are the same as conductors A50 and B60, and are used to provide two remaining parallel paths associated with the same phase (e.g., phase U) as conductors A and B. Conductors C and D are configured to be disposed in an even number of layers (i.e., layers #2, #4, #6, and #8) of the slots of the stator core associated with that phase. Thus, conductor AD provides a set of conductors for one phase of the motor of winding arrangement 40. When mounted on stator core 22, conductor AD is disposed in slot 30 associated with that phase.

[0049] In addition, due to Figures 4 to 10 The winding arrangement 40 is implemented as a three-phase winding arrangement, and it will also be appreciated that two additional sets of conductors (not shown) are provided for each of the other phases (e.g., Y phase and Z phase) to complete all phases of the winding arrangement. Each additional set of conductors is identical to the conductor AD associated with the first phase (e.g., U phase). These additional sets of conductors are then mounted onto the stator core 22 and positioned in the slots 30 associated with their respective phases.

[0050] Now refer to Figure 6 and Figure 7 A two-dimensional diagram is provided, showing a linear representation of the arrangement of conductor A50 relative to conductor B60 after all conductors are mounted on the stator core 22. (See diagram for reference.) Figure 6As shown, the slotted portion of conductor A50 is always in a slot adjacent to the slotted portion of conductor B60. In other words, conductor A is in a slot to the left or right of conductor B, depending on the slot being observed. Furthermore, all end turns of conductor A are nested with end turns of conductor B (i.e., end turns are positioned above / below or outside / inside each other), except for the intersecting upper intermediate end turns 52c and 62c. In other words, end turns of conductor A are nested above or below end turns of conductor B, and vice versa, depending on the layer in which the end turns are located; therefore, except at one location along the length of conductors A and B, the end turns of conductor A and the end turns of conductor B do not intersect each other. Specifically, the upper intermediate end turns 52c and 62c intersect each other at the intersection between layers #3 and #5.

[0051] Figure 7 Shown Figure 6 An enlarged view of the central part. (See image below.) Figure 7 As shown on the left, in outer layers #1 and #3, the upper outer layer end coil 52a (with a pitch of 7) of conductor A extends completely above the upper outer layer end coil 62a (with a pitch of 5) of conductor B, and there is no contact or crossing between conductors A and B at these end coil positions. In other words, end coil 52a is nested outside end coil 62a, so end coil 62a can be considered nested inside end coil 52a. Meanwhile, the lower outer layer end coil 64a (with a pitch of 7) of conductor B extends completely below the lower outer layer end coil 54a (with a pitch of 5) of conductor A, and there is no crossing between conductors A and B at these end coil positions in outer layers #1 and #3. In other words, end coil 54a is nested inside end coil 64a, so end coil 64a is nested outside end coil 54a.

[0052] like Figure 7 As shown on the right, in inner layers #5 and #7, the upper inner layer end coil 52b (with a pitch of 5) of conductor A extends completely below the upper inner layer end coil 62b (with a pitch of 7) of conductor B, and there is no contact or crossing between conductors A and B at these end coil positions. In other words, end coil 52b is nested within end coil 62b, so end coil 62b can be considered nested outside end coil 52b. Simultaneously, the lower inner layer end coil 64b (with a pitch of 5) of conductor B extends inside the lower inner layer end coil 54b (with a pitch of 7) of conductor A, and there is no crossing between conductors A and B at these end coil positions in inner layers #5 and #7. In other words, end coil 54b is nested outside end coil 64b, so end coil 64b is nested within end coil 54b.

[0053] Continue to refer to Figure 7The middle end coil 52c of conductor A and the middle end coil 62c of conductor B have the same pitch (i.e., a pitch of 7). Therefore, conductors A and B cross at this location, resulting in a phase shift. This phase shift can be indicated in... Figure 7 It is easily identifiable that, to the left of the intermediate end turns 52c and 62c, the upper end turn 52a of conductor A is outside the upper end turn 62a of conductor B, but to the right of the intermediate end turns, the upper end turn 52b of conductor A is inside the upper end turn 62b of conductor B. Similarly, to the left of the intermediate end turns 52c and 62c, the lower end turn 54a of conductor A is inside the lower end turn 64a of conductor B, but to the right of the intermediate end turns, the lower end turn 54b of conductor A is outside the lower end turn 64b of conductor B.

[0054] Figure 8 Similar to Figure 7 However, the diagram shows the intermediate end turns of conductors A and B for all three phases (i.e., U-phase, V-phase, and W-phase) of the winding arrangement. In this diagram, U-phase conductor A is represented as U(A), U-phase conductor B as U(B), V-phase conductor A as V(A), V-phase conductor B as V(B), and W-phase conductor A as W(A) and W-phase conductor B as W(B). Figure 8 As shown on the left, at the upper outer end turn 72a, the conductor A for each phase is nested outside the conductor B for the same phase. Furthermore, at the lower outer end turn 74a, the conductor A for each phase is nested inside the conductor B for the same phase. At the middle end turn 74c, the conductor A for each phase crosses the conductor B. Subsequently, at the upper inner end turn 72b, the conductor A for each phase is nested inside the conductor B for the same phase. Furthermore, at the lower inner end turn 74b, the conductor A for each phase is nested outside the conductor B for the same phase.

[0055] Figure 9A and Figure 9B It shows the combination Figures 4 to 8 A cross-sectional view of the stator describing the winding arrangement. Figure 9A In the diagram, the middle block with horizontal lines represents the stack of stator cores (e.g., a cut along one of the teeth); the vertical lines are the end turns indicating different layers. Figure 9B Shown Figure 9A Enlarged view of the upper end coil and the arrangement of layers 1-8 from the outer layer to the inner layer in the stator slot.

[0056] Now refer to Figure 10 This shows a cross-sectional view of a portion of the stator assembly 20. Figure 10The slot 30 of the stator core 22 is shown, in which the conductor 42 for one phase (e.g., phase U) of the winding is located. As discussed earlier herein, each phase includes four parallel paths (e.g., conductors AD discussed above). Therefore, Figure 10 Each conductor 42 includes a label “A”, “B”, “C”, or “D” to indicate its association with one of the four parallel paths of the phase. Conductors A and B are located in the odd-numbered layers of each slot, and conductors C and D are located in the even-numbered layers of each slot. The phase leads of conductors C and D are offset by one pole from the phase leads of conductors A and B. It will be appreciated that phases V and W are similar to those shown for phase U, but phase V is shifted two slots clockwise from phase U, and phase W is shifted four slots clockwise from phase U.

[0057] like Figure 10 As shown, conductors from adjacent slots of each phase of the winding arrangement are nested in a certain way (e.g., above / outside or below / inside) and do not cross each other (except for the upper middle end turns 52c and 62c). For example, the upper end turn 52A of path A is nested outside the upper end turn 62a of path B, and the lower end turn 54a of path A is nested inside the lower end turn 64a of path B. Similar nesting occurs in the remaining conductors in adjacent slots of the same phase and in adjacent slots of other phases.

[0058] Figure 10 Also shown is a 4-8-4 conductor arrangement for one phase of the winding on three consecutive slot groups. With this 4-8-4 conductor arrangement, four phase conductors are located in the first / left slot closer to OD, eight phase conductors are located in the second / center slot, and four phase conductors are located in the third / right slot closer to ID. Figure 10 Three different slot groups are shown, including a first slot group 30a, a second slot group 30b, and a third slot group 30c, for holding conductors for one phase of the winding. The conductors in the first slot group 30a are connected to the conductors in the second slot group 30b via lower end turns (i.e., end turns on one side of the stator core 22), and the conductors in the second slot group 30b are further connected to the conductors in the third slot group 30c via upper end turns (i.e., end turns on the other side of the stator core). In the first slot group 30a and the third slot group 30c, the conductors in layers 1 to 4 of the left slot are configured as BDBD, the conductors in layers 1 to 8 of the middle slot are configured as ACACBDBD, and the conductors in layers 5 to 8 of the right slot are configured as ACAC. In the second slot group 30b, the conductors in layers 1 to 4 of the left slot are configured as ACAC, the conductors in layers 1 to 8 of the middle slot are configured as BDBDACAC, and the conductors in layers 5 to 8 of the right slot are configured as BDBD.

[0059] Figures 4 to 10 The winding arrangement shown offers several advantages. First, although wires A and C appear to have different shapes from wires B and D during installation, all wires AD are actually identical in shape. This identical shape of wires AD is understandable because each wire in AD is symmetrical about the midpoint loop, thus allowing each wire in AD to be formed by creating the same serrated shape, and then flipping / rotating half of the wire to produce wires A and C, as well as wires B and D (e.g., simply rotating wires B and D around the midpoint loop after forming to create a difference from wires A and C). In other words, by forming identical wire portions (i.e., two identical wires that look like "wire A"), and then rotating one of the two wires 180° around the midpoint to form "wire B", it is possible to simultaneously produce… Figure 4 and Figure 5 The diagram shows wires A and B. Since wire C is identical to wire A and wire D is identical to wire B, all four wires can be formed into the same shape simultaneously, and then two of them are rotated before being installed into the stator core. Therefore, a method for forming windings on a stator is disclosed, wherein two or more wires (e.g., wires A and B) are generated simultaneously, and then one wire is rotated 180° and nested with another wire (e.g., as shown in the diagram). Figure 3 (As shown), and then insert these wires into the slots of the stator.

[0060] Figure 11 Flowchart 1100 illustrates the method described above for forming windings on the stator. Figure 11 As shown, the method begins at box 1110, where multiple wires are bent to form a shape similar to... Figure 4 and Figure 5 The conductor A shown is a long, thin conductor with a grooved section and an end coil. After bending, at least some of the conductor is rotated 180° around the middle end coil, as described in box 1120. This rotation of the conductor around the middle end coil produces two distinct sets of conductors, similar to... Figure 4 and Figure 5 The wires A and B are shown. Subsequently, as described in box 1130, the wires from each group are moved closer to each other and nested together. For example, Figure 4 and Figure 5 Wire A and wire B are nested, producing a result similar to Figure 6The arrangement is shown. Then, as described in box 1140, the nested conductor is inserted into the slots of the stator core by inserting the slot segments one after another sequentially into the slots of the stator core, starting from one end of the nested conductor. Subsequently or simultaneously, additional conductors forming other parallel paths in the winding are inserted layer by layer into the slots of the stator core until a complete winding is formed. Advantageously, Figure 11 The method allows for the convenient formation of windings by bending multiple conductor segments into a single shape, rotating some conductors, nesting conductors, and then inserting the nested conductors into slots in the stator core.

[0061] Besides being easy to manufacture Figures 4 to 10 The disclosed winding arrangement also provides improved motor performance, including lower resistance. Furthermore, because the end turns are nested together and more compactly arranged than other winding arrangements after the windings are inserted into the stator core, the space occupied by the motor is slightly reduced.

[0062] Alternative implementation of winding arrangement

[0063] Now refer to Figure 12 In at least one first alternative embodiment, the winding arrangement 40 is constructed similarly to the above-mentioned reference. Figures 4 to 10 The construction is as described, but the pitch of the end circuits differs slightly. Specifically, the winding arrangement includes at least one conductor A50 having an N+1 pitch end circuit 52 (e.g., an upper end circuit) at a first axial end, an N-1 pitch end circuit 54 (e.g., a lower end circuit) at a second axial end, and an intermediate end circuit 52c with a pitch of N+2. For example, the pitch of the upper end circuit 52 may be 7, the pitch of the lower end circuit 54 may be 5, and the pitch of the intermediate end circuit 52c may be 8. The winding arrangement also includes at least one conductor B 60 opposite to conductor A, such that conductor B is flipped 180° relative to conductor A (i.e., the upper end turn becomes the lower end turn). Therefore, conductor B has an N-1 pitch end circuit 62 (e.g., an upper end circuit) at a first axial end, an N+1 pitch end circuit 64 (e.g., a lower end circuit) at a second axial end, and an intermediate end circuit 62c with a pitch of N. For example, the pitch of the upper end loop 62 can be 5, the pitch of the lower end loop 64 can be 7, and the pitch of the middle end loop 62c can be 6.

[0064] Figure 13The diagram illustrates a 4-8-4 conductor arrangement for one phase of a winding on three consecutive slot groups 30a, 30b, and 30c. In the first slot group 30a and the third slot group 30c, the conductors in layers 1 to 4 of the left slot are configured as BDBD, the conductors in layers 1 to 8 of the middle slot are configured as ACACACAC, and the conductors in layers 5 to 8 of the right slot are configured as BDBD. In the second slot group 30b, the conductors in layers 1 to 4 of the left slot are configured as ACAC, the conductors in layers 1 to 8 of the middle slot are configured as BDBDBDBD, and the conductors in layers 5 to 8 of the right slot are configured as ACAC.

[0065] Now refer to Figures 14 to 15 In at least one second alternative embodiment, the winding arrangement 40 is constructed similarly to the above-mentioned reference. Figure 12 and Figure 13 The aforementioned structure, but the pitch of the intermediate end coils is similar to... Figure 12 and Figure 13 The pitch of the intermediate end turns varies slightly. Specifically, the winding arrangement includes at least one conductor A50 having an N+1 pitch end loop 52 (e.g., an upper end loop) at a first axial end, an N-1 pitch end loop 54 (e.g., a lower end loop) at a second axial end, and an intermediate end loop 52c with a pitch of N. For example, the pitch of the upper end loop 52 may be 7, the pitch of the lower end loop 54 may be 5, and the pitch of the intermediate end loop 52c may be 6. The winding arrangement also includes at least one conductor B 60 opposite to conductor A, such that conductor B is flipped 180° relative to conductor A (i.e., the upper end turn becomes the lower end turn). Therefore, conductor B has an N-1 pitch end loop 62 (e.g., an upper end loop) at a first axial end, an N+1 pitch end loop 64 (e.g., a lower end loop) at a second axial end, and an intermediate end loop 62c with a pitch of N-2. For example, the pitch of the upper end loop 62 can be 5, the pitch of the lower end loop 64 can be 7, and the pitch of the middle end loop 62c can be 4.

[0066] Figure 15The diagram illustrates a 4-8-4 conductor arrangement for one phase of a winding phase on three consecutive slot groups 30a, 30b, and 30c. In the first slot group 30a and the third slot group 30c, the conductors in layers 5 to 8 of the left slot are arranged as ACAC, the conductors in layers 1 to 8 of the middle slot are arranged as ACACBDBD, and the conductors in layers 1 to 4 of the right slot are arranged as BDBD. In the second slot group 30b, the conductors in layers 5 to 8 of the left slot are arranged as BDBD, the conductors in layers 1 to 8 of the middle slot are arranged as BDBDACAC, and the conductors in layers 1 to 4 of the right slot are arranged as ACAC.

[0067] Now refer to Figures 16 to 17 In at least one second alternative embodiment, the winding arrangement 40 is constructed similarly to the above-mentioned reference. Figures 4 to 10 The aforementioned structure, but the pitch of the intermediate end coils is similar to... Figures 4 to 10 The pitch of the intermediate end loops differs slightly in the embodiments described. Therefore, for the outer layer, conductor A has an N+1 pitch end loop 52a (e.g., seven pitch) at the first axial end and an N-1 pitch end loop 54a (e.g., five pitch) at the second axial end. For the inner layer, conductor A has an N-1 pitch end loop 52b (e.g., five pitch) at the first axial end and an N+1 end loop 54b (e.g., seven pitch) at the second axial end. Conductor A also has an upper intermediate end loop 52c with a phase shift of N-1 (e.g., five pitch). In this embodiment, conductor B is the opposite of conductor A, and conductor B is rotated 180° relative to conductor A around the upper intermediate end loop 52c.

[0068] Figure 17 The diagram illustrates a 4-8-4 conductor arrangement for one phase of a winding phase on three consecutive slot groups 30a, 30b, and 30c. In the first slot group 30a and the third slot group 30c, the conductors in layers 5 to 8 of the left slot are configured as BDBD, the conductors in layers 1 to 8 of the middle slot are configured as ACACACAC, and the conductors in layers 1 to 4 of the right slot are configured as BDBD. In the second slot group 30b, the conductors in layers 5 to 8 of the left slot are configured as ACAC, the conductors in layers 1 to 8 of the middle slot are configured as BDBDBDBD, and the conductors in layers 1 to 4 of the right slot are configured as ACAC.

[0069] It will be recognized that different advantages can be appreciated from each of the aforementioned different embodiments. For example, Figures 4 to 10 and Figures 16 to 17Two implementations produce wires symmetrical around the middle end loop, allowing all wires to form the same serrated shape, and then half of the wires are flipped to produce wires A and B, as described above. On the other hand, in Figure 12 and Figure 13 as well as Figure 14 and Figure 15 In this implementation, intermediate terminal circuits do not cross each other, thereby reducing the chance of electrical short circuits.

[0070] Vehicle Applications

[0071] In at least one embodiment, a motor 10 comprising a winding arrangement having alternating winding pitches is provided in its application as part of a hybrid electric drive system, such as the drive system of a hybrid electric vehicle. Figure 18 As shown, the hybrid electric drive system 99 includes an electric motor 10 operatively connected to the drive shaft of an internal combustion engine 70. The electric motor 10 is also operatively connected to a transmission 80 via a torque converter or clutch 75. The transmission is operable to drive the wheels 85 of the hybrid electric vehicle. Additionally, the electric motor 10 is operatively connected to a battery pack 90 via a power electronic inverter / rectifier 95. The power electronic inverter / rectifier 95 is operable to supply power to the motor or draw power from the battery.

[0072] During operation of the hybrid electric vehicle, the motor functions as both a motor and a generator. Motor operation includes starter motor operation and vehicle driving operation. Initially, motor 10 operates as an electric starter motor to start the internal combustion engine 70. During this engine start-up period, clutch 75 disengages gearbox 80 from the motor. During low-speed vehicle driving operation, clutch 75 engages motor 10 and gearbox 80, allowing the motor to act as a propulsion drive, turning the vehicle's wheels 85. Motor 10 can also function as a propulsion assist device during vehicle acceleration. During high-speed vehicle travel, motor 10 is driven by the internal combustion engine 70 and operates as an alternator, providing power to onboard electrical loads and charging the battery pack. Finally, during vehicle braking and deceleration, motor 10 acts as a generator, converting kinetic energy from the vehicle into electrical energy to charge the battery pack 90.

[0073] The detailed description of one or more embodiments of the stator winding connection arrangement described above is presented herein by way of example only and not as a limitation. It will be appreciated that certain individual features and functions described herein may be advantageous without combining them with other features and functions described herein. Furthermore, it will be appreciated that various alternatives, modifications, variations, or improvements, or substitutions thereof, to the disclosed embodiments and other features and functions described above can be voluntarily combined into many other different embodiments, systems, or applications. Those skilled in the art may subsequently make such alternatives, modifications, variations, or improvements that are not currently foreseen or anticipated, and these are also intended to be included in the appended claims. Therefore, the spirit and scope of any appended claims should not be limited to the description of the embodiments contained herein.

[0074] Various embodiments are presented in the accompanying drawings and description. Alternative embodiments and equivalents of the invention can be devised without departing from the spirit or scope of the invention. It should be noted that any discussion herein with reference to "one embodiment," "implementation," "exemplary embodiment," etc., indicates that the described embodiment may include specific features, structures, or characteristics, and such specific features, structures, or characteristics are not necessarily included in every embodiment. Furthermore, references to the foregoing do not necessarily include references to the same embodiment. Finally, whether explicitly described or not, those skilled in the art will readily understand that each specific feature, structure, or characteristic of a given embodiment can be used in combination with those of any other embodiments discussed herein.

Claims

1. A stator for an electric motor, comprising: A stator core having multiple slots formed therein, the stator core defining a first axial end and a second axial end; as well as A winding disposed on the stator core, the winding comprising slot segments disposed in layers of the plurality of slots and end turns connecting the slot segments, the winding defining: The first winding path includes an outer end coil, an inner end coil, and a transition end coil located between the outer end coil and the inner end coil; as well as The second winding path includes an outer end turn, an inner end turn, and a transition end turn located between the outer end turn and the inner end turn, wherein the outer end turn of the second winding path is nested with the outer end turn of the first winding path, and wherein the inner end turn of the second winding path is nested with the inner end turn of the first winding path. Wherein, the outer end coil of the first winding path is defined by a first pitch at the first axial end and a second pitch at the second axial end, the first pitch being different from the second pitch, and wherein the transition end coil of the first winding path is defined by a third pitch; Wherein, the outer end coil of the second winding path is defined by the second pitch on the first axial end and the first pitch on the second axial end; Wherein, the inner layer end turns of the first winding path are defined by the second pitch on the first axial end and the first pitch on the second axial end; and The inner end coil of the second winding path is defined by the first pitch on the first axial end and the second pitch on the second axial end.

2. The stator according to claim 1, wherein, The transition end coil is an intermediate end coil, and the intermediate end coil of the second winding path intersects with the intermediate end coil of the first winding path.

3. The stator according to claim 1, wherein, N is a defined number of slots per phase per pole for the stator, wherein the first pitch and the third pitch are N+1, and wherein the second pitch is N-1.

4. The stator according to claim 1, wherein, N is a defined number of slots per phase per pole of the stator, wherein the first pitch is N+1, and wherein the second and third pitches are N-1.

5. The stator according to claim 4, wherein N = 6.

6. A stator for an electric motor, comprising: A stator core having multiple slots formed therein, the stator core defining a first axial end and a second axial end; as well as A winding disposed on the stator core, the winding comprising slot segments disposed in layers of the plurality of slots and end turns connecting the slot segments, the winding defining: The first winding path includes an outer end coil, an inner end coil, and a transition end coil located between the outer end coil and the inner end coil; as well as The second winding path includes an outer end turn, an inner end turn, and a transition end turn located between the outer end turn and the inner end turn, wherein the outer end turn of the second winding path is nested with the outer end turn of the first winding path, and wherein the inner end turn of the second winding path is nested with the inner end turn of the first winding path. The outer and inner end turns of the first winding path are defined by a first pitch at the first axial end and a second pitch at the second axial end, and the transition end turns of the first winding path are defined by a third pitch; and The outer end turn and inner end turn of the second winding path are defined by a second pitch on the first axial end and a first pitch on the second axial end, and the transition end turn of the second winding path is defined by a fourth pitch, wherein the first pitch, second pitch, third pitch and fourth pitch are all different pitches.

7. The stator according to claim 6, wherein, N is the defined number of slots per phase per pole of the stator, wherein the first pitch is N+1, the second pitch is N-1, the third pitch is N+2, and the fourth pitch is N.

8. The stator according to claim 6, wherein, N is a defined number of slots per phase per pole of the stator, wherein the first pitch is N+1, the second pitch is N-1, the third pitch is N, and the fourth pitch is N-2.

9. The stator according to claim 8, wherein, N＝6。 10. A stator for an electric motor, comprising: A stator core having multiple slots formed therein, the stator core defining a first axial end and a second axial end; as well as A multi-phase winding is disposed on the stator core, each winding phase having multiple parallel paths. Each parallel path completes multiple turns around the stator core, and each parallel path includes a series of slot segments disposed in layers of multiple slots and end turns alternately connecting continuous slot segments on the first axial end and continuous slot segments on the second axial end. The pitch of the end turns of the slot segment connecting at least one parallel path alternates between a first pitch on the first axial end and a second pitch on the second axial end, the second pitch being different from the first pitch. The plurality of parallel paths include a first path and a second path, wherein the end coils of the first path alternate between a first pitch at the first axial end and a second pitch at the second axial end, and the end coils of the second path alternate between a second pitch at the first axial end and a first pitch at the second axial end.

11. The stator according to claim 10, wherein, The slot segment is arranged in a single column in each of the plurality of slots and defines multiple layers within each slot.

12. The stator according to claim 11, wherein, Each parallel path of the winding includes an outer end turn, an inner end turn, and a transition end turn provided by an intermediate end turn between the outer end turn and the inner end turn.

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