Motor rotor comprising a helical keyway cooperating with a laminated core

Abstract

The present disclosure relates to electric machine rotors including a helical keyway cooperating with a laminated core. An electric machine includes a slot defined by a rotor hub, the slot being skewed relative to an axis of rotation; a first stack of first laminations mounted to the rotor hub, the first laminations each including a first tab seated in the slot, cooperation between the first tabs at opposite ends of the first stack and the slot limiting movement of the first stack relative to the rotor hub; a plurality of first magnets mounted to the first stack; a second stack of second laminations mounted to the rotor hub, the second laminations each including a second tab seated in the slot, cooperation between the second tabs at opposite ends of the second stack and the slot limiting movement of the second stack relative to the rotor hub; and a plurality of second magnets mounted to the second stack. The plurality of first magnets and the plurality of second magnets are skewed relative to one another.

Description

[0001] The information provided in this section is for the purpose of generally presenting the background of this disclosure. The work of the currently attributed inventors, to the extent described in this section, and in respect of aspects that may not otherwise qualify as prior art at the time of filing, is neither expressly nor implied to be in conflict with the prior art of this disclosure. Technical Field

[0002] This disclosure relates to a rotor assembly for an electric motor. Background Technology

[0003] An electric motor consists of a stator and a rotor. The stator typically includes a stator core and stator windings. The rotor is housed inside the stator core and is rotatably mounted on bearings. The rotor core comprises multiple laminated plates that are mounted to the rotor hub or shaft. In the case of a permanent magnet motor-generator, magnets are mounted to the laminated plates. The rotor interacts with the magnetic field generated by the stator to produce motion in the case of an electric motor, or to generate electricity in the case of a generator. Summary of the Invention

[0004] Among various features, this disclosure provides an electric motor comprising: a rotor hub configured to rotate about a rotation axis within a stator; a slot defined by the rotor hub, the slot being skewed relative to the rotation axis; a first stack of first laminated sheets mounted to the rotor hub, each of the first laminated sheets including a first tab disposed in the slot, the cooperation between the first tabs at opposite ends of the first stack and the slot limiting movement of the first stack relative to the rotor hub; a plurality of first magnets mounted to the first stack; a second stack of second laminated sheets mounted to the rotor hub, each of the second laminated sheets including a second tab disposed in the slot, the cooperation between the second tabs at opposite ends of the second stack and the slot limiting movement of the second stack relative to the rotor hub; and a plurality of second magnets mounted to the second stack. The plurality of first magnets and the plurality of second magnets are skewed relative to each other.

[0005] Another feature is that the motor is a permanent magnet motor-generator.

[0006] In another feature, the first stack and the second stack are identical, and the motor also includes a plurality of additional stacks that are identical to the first stack and the second stack and are mounted to the rotor hub, and each of the first stack, the second stack and the plurality of additional stacks is rotated and offset relative to each other about the axis of rotation.

[0007] In another feature, the groove extends at an angle of 4°–5° relative to the axis of rotation.

[0008] In another feature, the first and second stacks are identical, mounted directly adjacent to each other to the rotor hub, and rotated 1° off-center about the axis of rotation.

[0009] In another feature, the groove defines a pair of opposing flanges, with a first tab at the opposite end of the first stack and a second tab at the opposite end of the second stack positioned below the pair of opposing flanges.

[0010] In another feature, the first tab is aligned parallel to the axis of rotation; the second tab is aligned parallel to the axis of rotation; and the first and second tabs are rotated and offset relative to each other about the axis of rotation.

[0011] In another feature, the width of each of the first tabs and each of the second tabs is less than the distance between the opposing flanges of the groove.

[0012] In another feature, the first tabs are arranged in a first group with alternating widths, and the second tabs are arranged in a second group with alternating widths.

[0013] In another feature, the first protrusion at the opposite ends of the first stack is relatively wider than the first protrusion of the adjacent first group, and the second protrusion at the opposite ends of the second stack is relatively wider than the second protrusion of the adjacent second group.

[0014] In another feature, the first group includes at least four first stacked sheets, and the second group includes at least four second stacked sheets.

[0015] Among various features, this disclosure also provides an electric motor comprising: a rotor hub configured to rotate within a stator about a rotation axis; a slot defined by the rotor hub, the slot being skewed relative to the rotation axis; a first stack mounted to a first stack of first layers, each of the first stacks including a group of first tabs aligned parallel to the rotation axis and arranged having alternating widths, the cooperation between relatively wide first tabs at opposite ends of the first stack and the slot limiting movement of the first stack relative to the rotor hub; a plurality of first magnets mounted to the first stack; a second stack mounted to a second stack of second layers of the rotor hub, each of the second stacks including a group of second tabs aligned parallel to the rotation axis and arranged having alternating widths, the cooperation between relatively wide second tabs at opposite ends of the second stack and the slot limiting movement of the second stack relative to the rotor hub; and a plurality of second magnets mounted to the second stack. The first stack and the second stack are identical, and the first stack rotates relative to the second stack such that the first tabs and the second tabs are rotated and offset relative to each other about the rotation axis.

[0016] In another feature, the motor also includes a plurality of additional stacks that are identical to the first and second stacks and are mounted to the rotor hub, with each of the first stack, the second stack and the plurality of additional stacks rotating off-center about the axis of rotation.

[0017] In another feature, the groove extends at an angle of 4°-5° relative to the axis of rotation; and the first stack and the second stack are directly adjacent to each other and rotate about the axis of rotation by 1°.

[0018] Another feature is that the motor is a permanent magnet motor-generator.

[0019] Among various features, this disclosure also provides an electric motor comprising: a stator including stator coils; a rotor hub within the stator and configured to rotate about a rotation axis; a slot defined by the rotor hub, the slot being skewed relative to the rotation axis; a first stack mounted to a first stack of first layers, each of the first stacks including a group of first tabs arranged with alternating widths, the cooperation between relatively wide first tabs at opposite ends of the first stack and the slot limiting movement of the first stack relative to the rotor hub; a plurality of first magnets mounted to the first stack; a second stack mounted to a second stack of second layers of the rotor hub, each of the second stacks including a group of second tabs arranged with alternating widths, the cooperation between relatively wide second tabs at opposite ends of the second stack and the slot limiting movement of the second stack relative to the rotor hub; and a plurality of second magnets mounted to the second stack. The first tabs and the second tabs are rotationally offset relative to each other about the rotation axis.

[0020] In another feature, the first stack is exactly the same as the second stack, and the first stack is rotated relative to the second stack.

[0021] In another feature, the first tab is aligned parallel to the axis of rotation, and the second tab is aligned parallel to the axis of rotation.

[0022] In another feature, the groove extends at an angle of 4°-5° relative to the axis of rotation; and the first stack and the second stack are directly adjacent to each other and rotate about the axis of rotation by 1°.

[0023] In another feature, the width of each of the first tabs and each of the second tabs is less than the distance between the opposing flanges of the groove.

[0024] Other applicable areas of this disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0025] This disclosure also includes the following technical solutions:

[0026] 1. An electric motor, comprising:

[0027] A rotor hub configured to rotate about a rotation axis within a stator;

[0028] A slot defined by the rotor hub, the slot being skewed relative to the axis of rotation;

[0029] A first stack of first laminated sheets is mounted to the rotor hub, each of the first laminated sheets including a first tab disposed in the slot, the cooperation between the first tabs at opposite ends of the first stack and the slot restricting the movement of the first stack relative to the rotor hub.

[0030] Multiple first magnets are installed onto the first stack;

[0031] A second stack of second laminated sheets is mounted to the rotor hub, each of the second laminated sheets including a second tab disposed in the slot, the cooperation between the second tabs at opposite ends of the second stack and the slot restricting movement of the second stack relative to the rotor hub; and

[0032] Multiple second magnets are installed onto the second stack.

[0033] The plurality of first magnets and the plurality of second magnets are tilted relative to each other.

[0034] 2. The motor according to Scheme 1, wherein the motor is a permanent magnet motor-generator.

[0035] 3. The motor according to Scheme 1, wherein:

[0036] The first stack and the second stack are identical, and the motor further includes multiple additional stacks that are identical to the first stack and the second stack, mounted to the rotor hub.

[0037] Each of the first stack, the second stack, and the plurality of additional stacks is rotated and offset relative to each other about the axis of rotation.

[0038] 4. The motor according to Scheme 1, wherein the slot extends at an skew angle of 4°-5° relative to the axis of rotation.

[0039] 5. The motor according to embodiment 4, wherein the first stack and the second stack are identical, directly adjacent to each other, and rotated 1° about the axis of rotation.

[0040] 6. The motor according to embodiment 1, wherein the slot defines a pair of opposing flanges, and a first tab at an opposing end of the first stack and a second tab at an opposing end of the second stack are disposed below the pair of opposing flanges.

[0041] 7. The motor according to Scheme 1, wherein:

[0042] The first tab is aligned parallel to the axis of rotation;

[0043] The second tab is aligned parallel to the axis of rotation; and

[0044] The first tab and the second tab rotate and offset relative to each other about the axis of rotation.

[0045] 8. The motor according to Scheme 1, wherein the width of each of the first tabs and each of the second tabs is less than the distance between the opposite flanges of the slot.

[0046] 9. The motor according to claim 1, wherein the first tab is arranged in a first group having alternating widths, and the second tab is arranged in a second group having alternating widths.

[0047] 10. The motor according to claim 9, wherein the first tab at the opposite end of the first stack is relatively wider than the first tab of the adjacent first group, and the second tab at the opposite end of the second stack is relatively wider than the second tab of the adjacent second group.

[0048] 11. The motor according to claim 9, wherein the first group comprises at least four first laminated sheets, and the second group comprises at least four second laminated sheets.

[0049] 12. An electric motor, comprising:

[0050] A rotor hub configured to rotate about a rotation axis within a stator;

[0051] A slot defined by the rotor hub, the slot being skewed relative to the axis of rotation;

[0052] First stacks mounted to first stacks of first stacks of rotor hub, each of the first stacks including first tabs aligned parallel to the axis of rotation and arranged in groups of alternating widths, the cooperation between relatively wide first tabs at opposite ends of the first stacks and the slots restricting movement of the first stacks relative to the rotor hub.

[0053] Multiple first magnets are installed onto the first stack;

[0054] A second stack is mounted to a second stack of a second layer of the rotor hub, each of the second stacks including a group of second tabs aligned parallel to the axis of rotation and arranged with alternating widths, the cooperation between the relatively wide second tabs at opposite ends of the second stack and the slots restricting movement of the second stack relative to the rotor hub; and

[0055] Multiple second magnets are installed into the second stack.

[0056] The first stack is identical to the second stack, and the first stack is rotated relative to the second stack such that the first tab and the second tab rotate and offset relative to each other about the axis of rotation.

[0057] 13. The motor according to claim 12, further comprising a plurality of additional stacks identical to the first stack and the second stack, mounted to the rotor hub.

[0058] Each of the first stack, the second stack, and the plurality of additional stacks is rotated and offset relative to each other about the axis of rotation.

[0059] 14. The motor according to Scheme 12, wherein:

[0060] The groove extends at an angle of 4°-5° relative to the axis of rotation; and

[0061] The first stack and the second stack are directly adjacent to each other and rotated 1° around the axis of rotation.

[0062] 15. The motor according to Scheme 12, wherein the motor is a permanent magnet motor-generator.

[0063] 16. An electric motor comprising:

[0064] Stator, the stator comprising stator coils;

[0065] A rotor hub, which is located within the stator and configured to rotate about a rotation axis;

[0066] A slot defined by the rotor hub, the slot being skewed relative to the axis of rotation;

[0067] First stacks mounted to first stacks of first stacks of rotor hub, each of the first stacks including first tabs arranged in groups of alternating widths, the cooperation between relatively wide first tabs at opposite ends of the first stacks and the slots restricting movement of the first stacks relative to the rotor hub;

[0068] Multiple first magnets are installed onto the first stack;

[0069] A second stack is mounted to a second layer of a second stack, each of the second stacks including a group of second tabs arranged with alternating widths, wherein cooperation between relatively wide second tabs at opposite ends of the second stack and the slot restricts movement of the second stack relative to the rotor hub; and

[0070] Multiple second magnets are installed into the second stack.

[0071] The first protrusion and the second protrusion rotate and offset relative to each other about the axis of rotation.

[0072] 17. The motor according to claim 16, wherein the first stack is identical to the second stack, and the first stack rotates relative to the second stack.

[0073] 18. The motor according to claim 16, wherein the first tab is aligned parallel to the axis of rotation, and the second tab is aligned parallel to the axis of rotation.

[0074] 19. The motor according to Scheme 16, wherein:

[0075] The groove extends at an angle of 4°-5° relative to the axis of rotation; and

[0076] The first stack and the second stack are directly adjacent to each other and rotated 1° around the axis of rotation.

[0077] 20. The motor according to claim 16, wherein the width of each of the first tabs and each of the second tabs is less than the distance between the opposite flanges of the slot. Attached Figure Description

[0078] This disclosure will be more fully understood in light of the specific embodiments and accompanying drawings, wherein:

[0079] Figure 1 This is a perspective view of an electric motor including a stator and rotor assembly according to this disclosure;

[0080] Figure 2 yes Figure 1 Side view of the rotor assembly;

[0081] Figure 3 This is another side view of the rotor assembly, where many stacks have been removed to expose the rotor hub and slots where the stacks are mounted;

[0082] Figure 4 This is a side view of the channel in which the stacked tabs are placed to mount the stack to the hub;

[0083] Figure 5 It is a perspective view of a stack of layers, each layer including tabs configured to be disposed within slots; and

[0084] Figure 6 This is a cross-sectional view of the groove, in which stacked tabs are placed.

[0085] In the accompanying drawings, reference numerals may be used repeatedly to identify similar and / or identical elements. Detailed Implementation

[0086] This disclosure relates to an electric motor that can be configured as a motor or a generator. For example, the motor may be a permanent magnet motor-generator configured for automotive or non-automotive applications. The motor typically includes a rotor hub configured to rotate about a rotational axis within a stator. The rotor hub defines a slot skewed relative to the rotational axis. A plurality of stacks are disposed on the rotor hub, the stacks being arranged in a stack. Each stack in each stack includes a tab within the stack. Each tab is sized and shaped to be received within the slot. The tabs are arranged in an alternating group of relatively wide tabs and relatively narrow tabs. The relatively wide tabs are located at opposite ends of each stack.

[0087] The cooperation between the relatively wide tabs at opposite ends of each stack and the slots locks the stacks to the hub, preventing rotation of the stacks relative to the hub. The relatively narrow tabs inside the wider tabs at opposite ends of the stacks do not contact the sidewalls of the slots or the outer flanges, reducing stress on the stacks. Alternating the arrangement of the relatively narrow tabs adjacent to the relatively wide tabs allows the relatively wide tabs to flex during assembly, as the stacks are pressed onto the hub, which generally further reduces stress on the relatively wide tabs and the stacks. Due to the slot deflection, the tabs of different stacks rotate and offset relative to each other about the axis of rotation. Magnets mounted to the stacks also rotate and offset relative to each other about the axis of rotation, reducing any occurrence of noise, vibration, and roughness.

[0088] The tabs of each stack of the stack are aligned parallel to the axis of rotation. However, the slots where the tabs are placed are offset relative to the axis of rotation. Therefore, only the corners of the relatively wide tabs at opposite ends of each stack contact the sidewalls and / or outer flanges of the slots. Furthermore, the corners of the tabs contacting the slots are relative corners (i.e., the left corner of the tab at one end of the stack contacts the left side of the slot, and the right corner of the tab at opposite ends of the stack contacts the right side of the slot). The tabs are configured such that only the corners of the relatively wide tabs at opposite ends of the stack contact the slots to lock the stack of the stack to the hub, accommodating any manufacturing variations that may exist between various hubs and stacks, thereby facilitating manufacturing and assembly.

[0089] Figure 1The illustration shows an example of a motor 10 according to this disclosure. Motor 10 can be any suitable electric motor-generator, such as a permanent magnet motor-generator. Motor 10 can be configured for any suitable automotive application, as well as any suitable non-automotive application.

[0090] The motor 10 typically includes a stator 20 and a rotor 50. The stator 20 includes multiple stator layers 22 and stator coils 30. The stator 20 surrounds the rotor 50. The rotor 50 is rotatable within the stator 20 about a rotation axis A, for example as... Figure 1-3 As illustrated in the diagram. Rotor 50 includes a shaft 52 and a hub 60, which is mounted to and rotatable with the shaft 52. Hub 60 defines a slot 62, which is skewed relative to the axis of rotation A, as shown in the diagram. Figure 3 As specifically illustrated in the image. (Reference) Figure 6 For example, groove 62 includes a pair of opposing flanges 64 and sidewalls 66. In some applications, groove 62 may be directly defined in shaft 52.

[0091] The rotor 50 also includes multiple stacked layers mounted to the hub 60. Any suitable number of stacked layers may be included. In the illustrated example, the motor 10 includes a first stacked layer 70A, a second stacked layer 70B, a third stacked layer 70C, and a fourth stacked layer 70D. Each of the stacked layers 70A-70D includes multiple layers 72 stacked together. Each layer 72 is bonded together in any suitable manner and is made of a thin sheet of metal such as silicon steel. The layers 72 may have any suitable thickness, such as 0.25 mm for each sheet. Each of the stacked layers 70A-70D is identical or substantially similar to each other.

[0092] refer to Figure 4-6 For example, each stack 72 includes a tab 80 extending inward toward the axial center of each stack 72 and toward the axis of rotation A. The tab 80 is positioned within a slot 62 to lock the stacks 70A-70D relative to the hub 60 and to prevent rotation of the stacks 70A-70D relative to the hub 60, thereby preventing backlash, as further explained below. Each of the stacks 70A-70D also includes a magnet 90, which, in the illustrated example, is spaced apart around the exterior of each of the stacks 70A-70D.

[0093] In each of the stacks 70A-70D, the tabs 80 are arranged in alternating groups of wide tabs 82W and narrow tabs 82N. The wide tabs 82W are relatively wider than the narrow tabs 82N. The narrow tabs 82N can be machined to a narrower size, for example, relative to the wide tabs 82W. The wide tabs 82W and narrow tabs 82N are arranged alternately across each of the rotor stacks 70A-70D (see, for example, see...). Figure 4 and Figure 5 Each group of wide tabs 82W and narrow tabs 82N may include any suitable number of tabs 80, such as four tabs 80 each with a thickness of 0.25 mm. Therefore, each group of wide tabs 82W and narrow tabs 82N may be 1 mm thick, or, for example, about 1 mm thick. The maximum width of the wide tabs 82W is less than the distance between the opposing flanges 64 of the slot 62, thereby facilitating the insertion of the tabs 80 into the slot.

[0094] Wide tabs 82W and narrow tabs 82N are arranged such that a set of wide tabs 82W′ is located at each end of the assembly of wide tabs 82W and narrow tabs 82N. A set of narrow tabs 82N is directly adjacent to the wide tabs 82W′ at the ends, which provides clearance for the wide tabs 82W′ to bend (or deflect) during insertion into the slot 62. Tabs 80 are configured such that when placed in the slot 62, only the wide tabs 82W′ at the opposite ends of each of the rotor stacks 70A-70D contact the sidewall 66 and / or flange 64 of the slot.

[0095] For example, and refer to Figure 4 The left side of the upper group of wide tabs 82W′ contacts the left side of groove 62, while the right side of the upper group of wide tabs 82W′ does not contact the right side of groove 62. The right side of the lower group of wide tabs 82W′ contacts the right side of groove 62, while the left side of the lower group of wide tabs 82W′ does not contact the left side of groove 62. Therefore, the stress transmitted to the stack 72 is relatively small compared to the case where both sides of the wide tabs 82W′ and all the remaining tabs 80 contact the sidewall 66 and / or flange 64. The tabs 80 are configured such that only the corners of the opposite wide tabs 82W′ at the opposite ends of the stack contact the groove 62 to lock the rotor stack stacks 70A-70D to the hub 60, accommodating any manufacturing variations that may exist between the various hubs 60 and the stack 72, thereby facilitating manufacturing and assembly.

[0096] When placed in slot 62, even if slot 62 is skewed relative to the axis of rotation A, the tabs 80 of each of the rotor stacks 70A-70D are aligned parallel to the axis of rotation A, for example... Figure 4As illustrated in the diagram, slot 62 can be skewed relative to the axis of rotation A at any suitable angle (such as about 4.0°, and particularly 4.5°). Because slot 62 is skewed and all tabs 80 are parallel to the axis of rotation, all rotor stacks 70A-70D are rotated offset relative to each other about the axis of rotation A. With slot 62 skewed at 4.5° relative to the axis of rotation A, adjacent rotor stacks in rotor stacks 70A-70D are rotated offset by 1° or about 1°. Therefore, tabs 80 and magnets 90 of adjacent rotor stacks in rotor stacks 70A-70D are rotated offset by 1° or about 1°. Arranging magnets 90 in this rotational offset reduces any cogging torque and / or torque fluctuations that may occur during the rotation of rotor 50, which reduces any noise, vibration, and irregularities that may occur during operation of motor 10.

[0097] The foregoing description is illustrative in nature and is not intended to limit this disclosure, its application, or use in any way. The broad teachings of this disclosure can be implemented in various forms. Therefore, although this disclosure includes specific examples, its true scope should not be so limited, as other modifications will become apparent upon examination of the drawings, specification, and the following claims. It should be understood that one or more steps within the method can be performed in different orders (or simultaneously) without altering the principles of this disclosure. Furthermore, although each of the embodiments described above is described as having certain features, any one or more of those features described with respect to any embodiment of this disclosure can be implemented and / or combined with features of any of the embodiments in other embodiments, even if such combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the arrangement of one or more embodiments with each other remains within the scope of this disclosure.

[0098] Various terms (including “connection,” “joint,” “link,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “set up”) are used to describe spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.). Unless explicitly described as “direct,” when describing the relationship between a first element and a second element in the foregoing disclosure, the relationship can be a direct relationship where no other intervening element exists between the first and second elements, or an indirect relationship where one or more intervening elements exist (spatially or functionally) between the first and second elements. As used herein, the phrases A, B, and C, at least one of which should be interpreted as referring to the logic (A OR B OR C) using non-exclusive logic OR, and should not be interpreted as referring to “at least one of A, at least one of B, and at least one of C.”

[0099] In the diagram, as indicated by the arrowheads, the direction of the arrows generally illustrates the flow of information (such as data or instructions) of interest. For example, when components A and B exchange various types of information, but the information transmitted from component A to component B is relevant to the diagram, the arrow can point from component A to component B. This unidirectional arrow does not imply that no other information is transmitted from component B to component A. Furthermore, for information sent from component A to component B, component B can send a request for or confirmation of receipt of that information to component A.

Claims

1. An electric motor, comprising: A rotor hub configured to rotate about a rotation axis within a stator; A slot defined by the rotor hub, the slot being skewed relative to the axis of rotation; A first stack of first laminated sheets is mounted to the rotor hub, each of the first laminated sheets including a first tab disposed in the slot, the cooperation between the first tabs at opposite ends of the first stack and the slot restricting the movement of the first stack relative to the rotor hub. Multiple first magnets are installed onto the first stack; A second stack of second laminated sheets is mounted to the rotor hub, each of the second laminated sheets including a second tab disposed in the slot, the cooperation between the second tabs at opposite ends of the second stack and the slot restricting the movement of the second stack relative to the rotor hub; as well as Multiple second magnets are installed onto the second stack. The plurality of first magnets and the plurality of second magnets are tilted relative to each other.

2. The motor according to claim 1, wherein, The motor is a permanent magnet motor-generator.

3. The motor according to claim 1, wherein: The first stack and the second stack are identical, and the motor further includes multiple additional stacks that are identical to the first stack and the second stack, mounted to the rotor hub. Each of the first stack, the second stack, and the plurality of additional stacks is rotated and offset relative to each other about the axis of rotation.

4. The motor according to claim 1, wherein, The groove extends at an angle of 4°-5° relative to the axis of rotation.

5. The motor according to claim 4, wherein, The first stack and the second stack are identical and are mounted directly adjacent to each other to the rotor hub, and are rotated 1° off-center about the axis of rotation.

6. The motor according to claim 1, wherein, The slot defines a pair of opposing flanges, with a first tab at the opposite end of the first stack and a second tab at the opposite end of the second stack positioned below the pair of opposing flanges.

7. The motor according to claim 1, wherein: The first tab is aligned parallel to the axis of rotation; The second protrusion is aligned parallel to the axis of rotation; and The first tab and the second tab rotate and offset relative to each other about the axis of rotation.

8. The motor according to claim 1, wherein, The width of each of the first tabs and each of the second tabs is less than the distance between the opposite flanges of the groove.

9. The motor according to claim 1, wherein, The first tabs are arranged in a first group with alternating widths, and the second tabs are arranged in a second group with alternating widths.

10. The motor according to claim 9, wherein, The first protrusion at the opposite end of the first stack is relatively wider than the first protrusion of the adjacent first group, and the second protrusion at the opposite end of the second stack is relatively wider than the second protrusion of the adjacent second group.

Images