Stator assembly

Abstract

A stator assembly for an electric motor includes a stator core having a plurality of teeth spaced apart to define slots; a coil wound around one of the plurality of teeth; a bobbin positioning a coil with respect to the teeth; and a slot liner located within the slot.

Description

Technical Field

[0001] The present invention relates to a stator assembly for an electric motor. Background Art

[0002] It is generally desirable to improve electric machines, such as electric motors, in various ways. For example, improvements may be needed in terms of size, weight, power density, manufacturing cost, efficiency, reliability, and noise. Summary of the Invention

[0003] According to a first aspect of the present invention, there is provided a stator assembly for an electric motor, the stator assembly comprising: a stator core including a plurality of teeth spaced apart to define slots; a coil wound around one of the plurality of teeth; a bobbin for positioning the coil relative to the tooth; and a slot liner located within the slot.

[0004] The bobbin can be used to control the positioning of the coil, which can enable a relatively high fill factor, such as greater than 55%, for the winding of the coil around the tooth. The fill factor is the ratio of the cross-sectional area of the conductive material of the coil to the cross-sectional area of the open space within the slot. At the same time, the slot liner can provide insulation to ensure compliance with creepage distance and clearance requirements. The combination of the bobbin and the slot liner can thus provide relevant insulation while also enabling a relatively high fill factor.

[0005] The slot liner can be formed of an electrically insulating material, such as a dielectric material.

[0006] The coil can be located within adjacent slots on either side of the tooth. The slot liner can substantially cover the surfaces of the adjacent slots on either side of the tooth.

[0007] The bobbin can include holes through which the tooth extends. The bobbin can be attached to the tooth by an adhesive, such as an adhesive located within the holes through which the tooth extends.

[0008] The bobbin can include a plurality of grooves, and the innermost layer of the coil can be located within the plurality of grooves. This can ensure that the winding is wound around the tooth in a predetermined pattern, which can ensure that the coil is wound around the tooth with a relatively high fill factor, such as when compared to an arrangement without a plurality of grooves. In particular, in the absence of a plurality of grooves, the coil may move along the length of the tooth during winding, which may result in misalignment of the coil and a relatively poor fill factor.

[0009] The bobbin may include a retaining member for retaining the coil within the slots, such as within adjacent slots on either side of a tooth. This can ensure the correct positioning of the coil and can ensure that the coil is maintained in a predetermined winding pattern, thereby ensuring a relatively high fill factor. The bobbin may include a body, and the retaining member may extend outwardly from the body along the outermost perimeter of the slot, such as extending outwardly from the body in opposite directions. The retaining member may extend in a generally circumferential direction. This can be used to inhibit the radially outward movement of the coil.

[0010] The retaining member may include a plurality of guiding channels, and at least a portion of the coil may be located within the plurality of guiding channels. This can ensure that the coil is maintained in a predetermined winding pattern, thereby ensuring a relatively high fill factor.

[0011] The tooth may include an inner end, the bobbin may include an inner guiding surface located around the inner end of the tooth, the inner guiding surface may include a guiding recess, and at least a portion of the initial turns of the coil may be located within the guiding recess. This can ensure that the coil is maintained in a predetermined winding pattern, thereby ensuring a relatively high fill factor. The inner end of the tooth may include the radially inner end of the tooth, such as one end of the tooth attached to the yoke of the stator core.

[0012] A plurality of teeth may be spaced apart to define a plurality of slots, and a slot liner may be located within adjacent slots on either side of the tooth. Using a single slot liner in adjacent slots can reduce the number of components as compared to an arrangement where a separate slot liner is required for each slot.

[0013] The slot liner may include a hole through which the tooth extends. This can enable the correct positioning of the slot liner relative to the tooth. The slot liner may include a base within which the hole is located, and first and second upright arms located at opposite ends of the base. In this way, the slot liner can extend through the bases of adjacent slots on either side of the tooth, and through the respective outer sidewalls of adjacent slots on either side of the tooth. An adhesive may be located within the hole of the slot liner, between the slot liner and at least one of the bobbin and the tooth. The slot liner may be in direct contact with the surfaces of adjacent slots on either side of the tooth, such that there is no adhesive between the slot liner and the surfaces of adjacent slots on either side of the tooth.

[0014] The slot liner may be formed of an elastically deformable material. This can ensure the proper positioning of the slot liner within adjacent slots on either side of the tooth, such as by enabling the slot liner to contract during insertion into the adjacent slot and expand once inserted to fill the corresponding slot.

[0015] The slot liner may overhang the ends of the respective adjacent slots on either side of the tooth. This can facilitate meeting the relevant creepage distance and clearance requirements.

[0016] The stator assembly can have a width of no more than 100 mm, for example a diameter of no more than 100 mm. Using a slot liner and a bobbin of the stator assembly with such dimensions can facilitate a relatively high fill factor while meeting the relevant creepage distance and clearance requirements. The stator assembly can have a width of no more than 75 mm or no more than 50 mm, for example a diameter. The stator assembly can include a width of about 28 mm, for example an outer diameter.

[0017] The stator assembly can include: a plurality of bobbins, each located around one of a plurality of teeth such that a portion of the bobbin is within corresponding adjacent slots on either side of the tooth; a plurality of coils, each coil wound around a corresponding bobbin; and a plurality of slot liners, each slot liner located within adjacent slots on either side of a corresponding tooth.

[0018] The stator core can include a yoke, and the teeth can be separate components attached to the yoke. Since the teeth are separate components of the yoke, the bobbin assembly can be located away from the yoke relative to the teeth, thus facilitating the winding of the coils and the positioning of the coils relative to the teeth. This may be especially the case when the stator assembly has a relatively small diameter, where the slots may be relatively small. Using teeth that are separate components of the yoke can facilitate the use of a mandrel winding method to wind the coils around the teeth. Compared with other winding methods, such as the fly winding method, mandrel winding can achieve a greater fill factor. Compared with an arrangement where the yoke and the teeth are integrally formed as a single component, using separate teeth of the yoke can also provide greater flexibility in the choice of the overall shape of the teeth. The teeth can be attached to the yoke by an adhesive.

[0019] The teeth can include a body and outer tooth tips extending outward from the outer ends of the body. Providing tooth tips can provide more stator material than corresponding stator assemblies without tooth tips, and thus can provide higher efficiency for an electric motor including the stator assembly. The outer tooth tips can extend outward from the outer ends of the body in opposite directions. The outer tooth tips can extend circumferentially from the outer ends of the body.

[0020] The teeth can include a body and inner tooth tips extending outward from the inner ends of the body. Providing tooth tips can provide more stator material than corresponding stator assemblies without tooth tips, and thus can provide higher efficiency for an electric motor including the stator assembly. The inner tooth tips can extend outward from the inner ends of the body in opposite directions. The inner tooth tips can extend circumferentially from the inner ends of the body.

[0021] The bobbin can include a first bobbin portion located around a first portion of the tooth and a second bobbin portion located around a second portion of the tooth, the first and second bobbin portions including separate components attached to each other. Providing the first and second bobbin portions attached to each other can facilitate the provision of radially outer tooth tips on the tooth, since the first and second bobbin portions can be together around the body of the tooth without the need to slide the bobbin over the tooth.

[0022] The first and second bobbin portions may overlap each other at the interface between the first and second bobbin portions. This overlap can absorb any manufacturing tolerances of the first and second bobbin portions of the teeth.

[0023] The interface between the first and second bobbin portions may be located at the axial end of the tooth. This can move the interface to an area where changes in the interface do not affect the fill factor within the slot, enabling a relatively high fill factor within the slot. The interface may extend in a substantially radial direction. The first and second bobbin portions may each extend axially along substantially the entire length of the stator tooth. The first and second bobbin portions may each have a width substantially corresponding to half the width of the stator tooth.

[0024] The slot liner may be located between the bobbin and a portion of the tooth. This can ensure that the slot liner is positioned and held in place by the bobbin and a portion of the tooth, for example without the need for adhesives etc.

[0025] The bobbin may include a first bobbin portion at a first end of the tooth and a second bobbin portion at a second end of the tooth opposite the first end of the tooth, the first and second bobbin portions comprising separate components. This can enable an arrangement where the first and second bobbin portions do not need to extend into the slot, and thus an arrangement with an increased fill factor can be achieved compared to an arrangement where the first and second bobbin portions extend into the slot.

[0026] The tooth may include a recess, and the first bobbin portion may include a protrusion received within the recess. This can provide an increased fill factor compared to an arrangement without a recess, in which the first bobbin portion extends further into the slot. The tooth may include a plurality of recesses, and each of the first and second bobbin portions may include a protrusion extending into the corresponding recess.

[0027] The stator core may include a yoke, and the teeth may be integrally formed with the yoke. This can reduce the number of components compared to an arrangement where the yoke and the teeth are separate components.

[0028] The bobbin may include a hole, and the outer end of the tooth may include an edge that does not cover the perimeter of the hole. This can facilitate the positioning of the bobbin relative to the tooth during manufacturing, for example by using the hole to enable the bobbin to slide onto the tooth.

[0029] The bobbin may include an integral component. This can reduce the number of components compared to an arrangement where the yoke and the teeth are separate components.

[0030] The bobbin may include a first bobbin portion located at a first end of the tooth and a second bobbin portion located at a second end of the tooth opposite the first end of the tooth, the first and second bobbin portions including separate components. This may enable an arrangement where the first and second bobbin portions do not need to extend into the slots, and thus, an arrangement with an increased fill factor can be achieved as compared to an arrangement where the first and second bobbin portions extend into the slots.

[0031] The first and second bobbin portions may each include a respective first member corresponding to the shape of the yoke and a respective second member corresponding to the shape of the tooth. For example, this may provide an increased cross-sectional area for the first and second bobbin portions that will be attached to the respective first and second ends of the tooth as compared to an arrangement without the first member. The yoke may be annular, and the first member may be annular. The stator core may include a plurality of teeth, and the first and second bobbin portions may include a respective plurality of second members corresponding to the plurality of teeth.

[0032] According to a second aspect of the present invention, there is provided an electric motor including a stator assembly according to the first aspect of the present invention.

[0033] According to a third aspect of the present invention, there is provided a vacuum cleaner including an electric motor according to the second aspect of the present invention.

[0034] According to a fourth aspect of the present invention, there is provided a cleaning head for a vacuum cleaner, the cleaning head including a rotatable member and an electric motor according to the second aspect of the present invention, the electric motor being configured to rotate the rotatable member.

[0035] The rotatable member may include an agitator, such as a brush bar, for agitating the surface to be cleaned.

[0036] According to a fifth aspect of the present invention, there is provided a fan assembly including an electric motor according to the second aspect of the present invention.

[0037] According to a sixth aspect of the present invention, there is provided a method including: providing a bobbin including a first hole; winding a coil around the bobbin; providing a slot liner including a second hole; providing a stator core including a plurality of teeth spaced apart to define a plurality of slots; passing one of the plurality of teeth through the second hole such that the slot liner is located in adjacent slots on either side of the tooth; and passing the tooth through the first hole such that the bobbin is located around the tooth and such that at least a portion of the bobbin and at least a portion of the coil are located in adjacent slots on either side of the tooth.

[0038] According to a seventh aspect of the present invention, there is provided a method comprising: providing stator teeth; providing a slot liner including a first hole; passing the stator teeth through the first hole such that the slot liner is located along the stator teeth; providing a first bobbin portion and a second bobbin portion separate from the first bobbin portion; connecting the first bobbin portion to the second bobbin portion such that the first and second bobbin portions are located around the stator teeth and holding the slot liner in place relative to the stator teeth; winding the bobbins to form a stator tooth subassembly; and fixing the stator tooth subassembly to the yoke of the stator core.

[0039] Where appropriate, the optional features of aspects of the present invention may be equivalently applied to other aspects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a first schematic view of a first embodiment of a stator assembly;

[0041] Figure 2 is Figure 1 a second schematic view of the stator assembly of

[0042] Figure 3 is Figure 1 an exploded view of the winding subassembly of the stator assembly of

[0043] Figure 4 is Figure 3 a first view of the bobbin of the winding subassembly of

[0044] Figure 5 is Figure 4 a second view of the bobbin of

[0045] Figure 6 is Figure 3 a view of the slot liner of the winding subassembly of

[0046] Figure 7 is a schematic view showing Figure 3 the coil positioning of the winding subassembly of

[0047] Figure 8 is a first schematic view of a second embodiment of a stator assembly;

[0048] Figure 9 is Figure 8 a second schematic view of the stator assembly of

[0049] Figure 10 is Figure 8 an exploded view of the winding subassembly of the stator assembly of

[0050] Figure 11 is Figure 10 a first view of the bobbin of the winding subassembly of

[0051] Figure 12 is Figure 11 a second view of the bobbin of

[0052] Figure 13 is a schematic view showing Figure 10 the coil positioning of the winding sub - assembly of

[0053] Figure 14 a schematic view of a third embodiment of the stator assembly;

[0054] Figure 15 a schematic view of a fourth embodiment of the stator assembly;

[0055] Figure 16 is Figure 15 an exploded view of the winding sub - assembly of the stator assembly of

[0056] Figure 17 a schematic view of an electric motor;

[0057] Figure 18 is including Figure 17 a schematic view of a vacuum cleaner including the electric motor of

[0058] Figure 19 is Figure 18 a schematic view of the cleaning head of the vacuum cleaner of

[0059] Figure 20 is including Figure 17 a schematic view of a hair care appliance including the electric motor of ; and

[0060] Figure 21 is including Figure 17 a schematic view of a fan assembly including the electric motor of . DETAILED DESCRIPTION

[0061] Figure 1 and 2 schematically show a first embodiment of a stator assembly 10, including a stator core 12 and six winding sub - assemblies 14.

[0062] The stator core 12 includes a yoke 16 and twelve teeth 18. The yoke 16 is annular, and the teeth 18 extend radially outward from the yoke 16. The yoke 16 and the teeth 18 are integrally formed. The stator core 12 is formed by a stack of laminations (not shown), each lamination including a yoke portion and a corresponding tooth portion, which together define the yoke 16 and the teeth 18. Each tooth 18 has a generally uniform rectangular cross - sectional shape. The teeth 18 are spaced apart to define a plurality of slots 19, each slot being generally V - shaped, although having a curved rather than pointed innermost region.

[0063] In Figure 3The individual winding sub - assembly 14 is shown separately in the exploded view. It should be understood that each winding sub - assembly 14 has the same form, and for the sake of brevity, only one winding sub - assembly is described here. The winding sub - assembly 14 includes a bobbin 20, a coil 22, and a slot liner 24.

[0064] The bobbin 20 is shown separately in Figure 4 and 5 The bobbin 20 includes a body 26, a guiding surface 28, and a retaining member 30.

[0065] The body 26 is generally rectangular - parallelepiped in shape and has side surfaces 32 extending from a first end 34 of the body 26 to a second end 35 of the body 26. The side surfaces 32 include a plurality of longitudinal grooves 36. The longitudinal grooves 36 have a generally semi - circular cross - sectional shape and are sized to receive a portion of the coil 22 therein. A rectangular hole 38 extends through the body 26. The shape and size of the rectangular hole 38 correspond to the cross - sectional area of one of the teeth 18.

[0066] The guiding surface 28 is located at the first end 34 of the body 26 and includes an edge extending outward from the first end 34 of the body 26. In some examples, the guiding surface 28 includes a guiding recess extending longitudinally along the guiding surface 28, and its shape and size correspond to receiving a portion of the coil 22 therein in a manner similar to the longitudinal grooves 36.

[0067] The retaining member 30 includes a first arm 40 and a second arm 42 extending outward from the second end 28 of the body 26. The first arm 40 and the second arm 42 extend outward to a greater extent than the guiding surface 28 and are slightly curved in the direction toward the body 26. The extent of each of the first arm 40 and the second arm 42 corresponds to a little more than half of the width of one of the outermost ends of the slot 19. In some examples, the first arm 40 and the second arm 42 include one or more guiding channels, and their shape and size correspond to receiving a portion of the coil 22 therein in a manner similar to the longitudinal grooves 36.

[0068] The body 26, the guiding surface 28, and the retaining member 30 are integrally formed of plastic, an electrically insulating material, such that the bobbin 20 is a single - piece structure. The body 26, the guiding surface 28, and the retaining member 30 together give the bobbin 20 a generally T - shaped cross - sectional shape, as Figure 5 shown.

[0069] The coil 22 includes a copper wire having a circular cross - sectional shape, and the wire is wound around the bobbin 20 in multiple turns, which will be described in more detail below.

[0070] The slot liner 24 is in Figure 6shown separately in the middle, and includes a main portion 44, a first side portion 46, and a second side portion 48. The main portion 44 is generally rectangular and has a hole 50 formed therein. The length of the slot liner 24 is greater than the length of one of the corresponding slots 19, and the width corresponds to the combined width of two adjacent slots 19 and the tooth 18 located between the two adjacent slots 19. The hole 50 of the slot liner 24 is generally rectangular, and its shape and size generally correspond to the cross-sectional shape of one of the corresponding teeth 18.

[0071] The first side portion 46 and the second side portion 48 extend upward from the main portion 44, and each is generally rectangular. The height of the first side portion 46 and the second side portion 48 from the main portion 44 substantially corresponds to the height of one of the teeth 18 or one of the corresponding slots 19.

[0072] The main portion 44, the first side portion 46, and the second side portion 48 are integrally formed of an elastically deformable electrical insulating material, so that the slot liner 24 is a one-piece structure.

[0073] To assemble the stator assembly 10, when the bobbin 20 is positioned away from the stator core 12, the coil 22 is wound around the bobbin 20. The innermost layer of the coil 20 is located in the longitudinal groove 36 of the linear side surface 32 of the bobbin 20. The guiding surface 28 and the holding member 30 are used to inhibit the coil 22 from moving relative to the bobbin 20 in the direction along the height of the body 26 of the bobbin 20. Figure 7 The position of the coil 22 relative to the bobbin 20 is schematically shown.

[0074] This process is repeated for each coil 22 and bobbin 20 of the stator assembly 10.

[0075] When it is desired to position the wound bobbin on the stator core 12, the slot liner 24 is positioned below the guiding surface 28 of the bobbin 20, so that the rectangular hole 38 of the bobbin 20 is aligned with the hole 50 of the slot liner 24. Then, the winding sub-assembly 14 is slid onto one of the teeth 18, and the tooth 18 passes through the hole 50 of the slot liner 24 and the rectangular hole 38 of the bobbin 20. Adhesive can be located in the slots 19 on either side of the tooth 18 and / or on the tooth 18 itself to fix the winding sub-assembly 14 in place.

[0076] When the winding sub - assembly 14 is located on the tooth 18, the bobbin 20 extends around the tooth 18, and the coil 22 is located within the slots 19 on either side of the tooth 18. The slot liner 24 is also located within the slots 19 on either side of the tooth 18. By using the bobbin to control the positioning of the coil 22, a relatively high fill factor, such as greater than 55%, can be achieved for the winding of the coil 22 around the tooth 18. At the same time, the slot liner 24 can provide insulation to ensure compliance with creepage distance and clearance requirements. The combination of the bobbin 20 and the slot liner 24 can thus provide relevant insulation while also enabling a relatively high fill factor.

[0077] The winding sub - assemblies 14 can be sequentially located on the respective teeth 18, or in fact all the winding sub - assemblies 14 can be located simultaneously, with the winding sub - assemblies 14 located on every other tooth 18 of the stator core 12.

[0078] Figure 8 and 9 A second embodiment of the stator assembly 100 is schematically shown, where the same reference numerals are used for clarity.

[0079] The stator assembly 100 includes a first stator core member 102 and six winding sub - assemblies 104.

[0080] The first stator core member 102 includes a yoke 106 and six integral teeth 108. The yoke 106 is annular, and the integral teeth 108 extend radially outward from the yoke 106. The stator core 102 is formed by a stack of laminations (not shown), each lamination including a yoke portion and a corresponding tooth portion that together define the yoke 106 and the integral teeth 108. Each tooth 108 has a cross - sectional width that slightly increases radially outward from the tooth 108, and has a tooth tip 110 that extends circumferentially from the end of the tooth 108 opposite the yoke 106.

[0081] In Figure 10 the exploded view, a single winding sub - assembly 104 is shown separately. It should be understood that each winding sub - assembly 104 has the same form, and for the sake of brevity, only one winding sub - assembly 104 is described here. The winding sub - assembly 104 includes a second stator core member 112, a bobbin 114, a coil 22, and a slot liner 116.

[0082] The second stator core member 112 includes a body 120, an inner portion 122, and a tooth tip 124. The second stator core member 112 can be considered a segmented stator tooth. The shape and dimensions of the body 120 and the tooth tip 124 correspond to one of the integral teeth 108. The inner portion 122 extends outward relative to the body 120 at the end of the second stator core member 112 opposite the tooth tip 124. The inner portion 122 has a range that substantially corresponds to the radially innermost spacing between adjacent integral teeth 108. The second stator core member 112 is formed by a plurality of laminations fixed together.

[0083] The first stator core member 102 and the second stator core member 122 jointly define the stator core.

[0084] Figure 11 and 12 The bobbin 114 is shown separately in [reference]. The bobbin 114 of the second embodiment of the stator assembly 100 is substantially the same as the bobbin 10 of the first embodiment, except that the bobbin 114 is formed by a first bobbin portion 126 and a second bobbin portion 128, the guiding surface 28 includes a guiding recess 130, and the holding member 130 includes a guiding channel 132.

[0085] The bobbin 114 is separated along its longitudinal axis L to define a first bobbin portion 126 and a second bobbin portion 128, each of the first bobbin portion 126 and the second bobbin portion 128 including a corresponding stepped interface 134, 136. When the first bobbin portion 126 and the second bobbin portion 128 are connected together, the first bobbin portion 126 and the second bobbin portion 128 jointly define the body 26, the guiding surface 28, and the holding member 30, including a rectangular aperture 36.

[0086] The guiding surface 28 of the bobbin 114 extends longitudinally and circumferentially outward from the body 26, and the guiding recess 130 is formed in a portion of the guiding surface 28 that extends longitudinally outward from the body 26. The shape and size of the guiding recess 130 are adapted to receive a portion of the coil 22, and when the coil 22 is wound around the bobbin 114, the initial portion of the first turn of the coil 22 is received.

[0087] The guiding channels 132 only partially extend along the first arm 40 and the second arm 42 of the holding member 30, and the shape and size of each guiding channel are adapted to receive a portion of the coil 22.

[0088] Except for the number of turns, the coil 22 of the second embodiment of the stator assembly 100 is substantially the same as the coil 22 of the first embodiment of the stator assembly 10.

[0089] The slot liner 116 of the second embodiment of the stator assembly 100 is substantially the same as the slot liner 24 of the first embodiment of the stator assembly 10, except that the first side portion 46 and the second side portion 48 are shaped to accommodate the tip 110 of the integral tooth 108.

[0090] For a second embodiment of the stator assembly 100, when the second stator core member 112 is positioned away from the first stator core member 102, the second stator core member 112 slides through the hole 50 of the slot liner 24 such that the major portion 46 of the slot liner 24 covers the inner portion 122 of the second stator core member 112. The first bobbin portion 126 and the second bobbin portion 128 are brought together around the body 120 of the second stator core member 112 and are fixed together by an adhesive. The bobbin 114 holds the slot liner 24 in place relative to the second stator core member 112.

[0091] Then, the coil 22 is wound around the bobbin 114 away from the first stator core member 102. The first turn of the coil 22 is located within the guiding recess 130 of the guiding surface 28 of the bobbin 114, and the innermost layer of the coil 22 is located within the longitudinal groove 36 of the linear side surface 32 of the bobbin 114. The turns of the coil 22 are also located within the guiding channels 132 of the first arm 40 and the second arm 42 of the retaining member 30. Figure 13 The position of the coil 22 relative to the bobbin 114 is schematically shown.

[0092] This process is repeated for each winding sub - assembly 104 of the stator assembly 10.

[0093] When it is desired to position the winding sub - assembly 104 relative to the first stator core member 102, the winding sub - assembly 104 is fixed between a pair of adjacent integral teeth 108 using an adhesive. The second stator core member 112 (e.g., segmented stator teeth) and the integral teeth 108 define the slots of the stator assembly 100, and the coil 22 is located within these slots.

[0094] Figure 14 A third embodiment of the stator assembly 200 is schematically shown.

[0095] The stator assembly 200 includes a stator core 202, a first bobbin portion 204 and a second bobbin portion, a first slot liner 206 and a second slot liner 208, and a coil 210.

[0096] The stator core 202 includes a yoke 212, six first teeth 214, and six second teeth 216. The yoke 212 is annular. The first teeth 214 extend radially outward from the yoke 212, and the radially outer ends of the first teeth 214 include circumferentially extending tooth tips 218. The second teeth 216 extend radially outward from the yoke 212 and are positioned in an alternating manner with the first teeth 214 to define slots 215.

[0097] The first bobbin part 204 and the second bobbin part have the same form, each having an annular part 220 and six tooth parts 222. The annular part 220 substantially corresponds to the shape and size of the yoke 212, and the tooth parts 222 substantially correspond to the shape and size of the second tooth 216. Although not shown, the tooth parts 222 may include grooves similar to the longitudinal grooves 36 of the first embodiment 10 of the stator assembly. The first bobbin part 204 and the second bobbin part are fixed to the corresponding first and second axial ends of the stator core 200 by an adhesive such that the annular part 220 covers the yoke 212 and the tooth parts 222 cover the second tooth 216.

[0098] The first slot liner 206 and the second slot liner 208 are each formed of an elastically deformable electrical insulating material and are generally shaped to correspond to the shape of one of the slots 215. The first slot liner 206 and the second slot liner 208 are each received in a corresponding slot 215.

[0099] The coil 210 includes a copper wire having a circular cross-sectional shape, and the wire is wound into multiple turns.

[0100] To assemble the third embodiment of the stator assembly 200, the first bobbin part 204 and the second bobbin part are fixed to their corresponding ends of the stator core 202, and the first slot liner 206 and the second slot liner 208 are located in the corresponding adjacent slots 215 on either side of one of the second teeth 216. The coil 210 is wound away from the stator core 202 and is then slotted over the second tooth 216 such that the coil 210 is located within the first slot liner 206 and the second slot liner 208.

[0101] It should be understood that for each of the remaining slots and the second teeth 216, additional slot liners and coils are utilized to form the complete stator assembly 200.

[0102] Figure 15 A fourth embodiment of the stator assembly 300 is schematically shown.

[0103] The stator assembly 300 includes a first stator core member 302 and six winding sub-assemblies 304.

[0104] The first stator core member 302 includes a yoke 306 and six integral teeth 308. The yoke 306 is annular, and the integral teeth 308 extend radially outward from the yoke 306. Each integral tooth 308 has a tooth tip 310 that extends circumferentially from an end of the tooth 308 opposite the yoke 306 and an undercut 313 located at the interface with the yoke 306. Figure 15 Only a pair of undercuts 313 are shown. Other forms of attachment mechanisms that do not utilize the undercuts 313 are also contemplated.

[0105] At Figure 16The individual winding sub - assembly 304 is shown separately in the exploded view. It should be understood that each winding sub - assembly 304 has the same form, and for the sake of brevity, only one winding sub - assembly 304 is described here. The winding sub - assembly 304 includes a second stator core member 312, a first bobbin portion 314 and a second bobbin portion 315, a coil 316, and a first slot liner 318 and a second slot liner 319.

[0106] The second stator core member 312 includes a body 320, an inner portion 322, and a tooth tip 324. The second stator core member 312 can be considered as a segmented stator tooth. The shape and size of the body 320 and the tooth tip 324 correspond to one of the integral teeth 308. The body 320 includes a recess 325.

[0107] The inner portion 322 extends outwardly relative to the body 320 at an end of the second stator core member 312 opposite to the tooth tip 324. The inner portion 322 has a range that substantially corresponds to the radially innermost spacing between adjacent integral teeth 308, and the shape and size of the end of the inner portion 322 are designed to be received within the corresponding undercut 313.

[0108] The first stator core member 302 and the second stator core member 322 together define the stator core.

[0109] The first bobbin portion 314 and the second bobbin portion 315 have substantially the same shape, each having a body 326, an inner member 328, an outer member 330, and a protrusion 332. The shape of the body 326 corresponds to the body 320 of the second stator core member 312, the shape of the inner member 328 corresponds to the inner portion 322 of the second stator core member 312, and the shape of the outer member 330 corresponds to the tooth tip 324 of the second stator core member 312. The edge of the body 326 extending between the inner member 328 and the outer member 330 includes a groove 332 for receiving a portion of the coil 316. The protrusion 332 extends orthogonally from the body 326, and its shape and size are designed to be received within the corresponding recess 325 of the second stator core member 312.

[0110] Except for the number of turns, the coil 316 of the fourth embodiment of the stator assembly 300 is substantially the same as the coil 22 of the first embodiment of the stator assembly 10.

[0111] The first slot liner 318 and the second slot liner 319 are formed of an elastically deformable electrical insulating material and define a generally V - shaped channel.

[0112] For a fourth embodiment of the stator assembly 300, a first bobbin portion 314 and a second bobbin portion 315 are fixed to respective ends of the second stator core member 312, and the protrusions 332 of the first bobbin portion 314 and the second bobbin portion 315 are located within the grooves 325 of the second stator core member 312. A first slot liner 318 and a second slot liner 319 are fixed to opposite sides of the second stator core member 312, and the coil 316 is wound around the body 320 of the second stator core member 312 such that the coil 316 is located within the first slot liner 318 and the second slot liner 319.

[0113] This process is repeated for each winding sub - assembly 304 of the stator assembly 300.

[0114] When it is desired to position the winding sub - assembly 304 relative to the first stator core member 302, the winding sub - assembly 304 is axially slid such that the inner portion 322 of the second stator core member 312 is slotted into the undercut 313 of the adjacent integral tooth 308 of the first stator core member 302. Adhesive can also be used to fix the winding sub - assembly 304 in place. This process is repeated for each winding sub - assembly 304 of the stator assembly 300.

[0115] Common to each of the first embodiment 10, the second embodiment 100, the third embodiment 200, and the fourth embodiment 300 of the stator assembly is the use of a bobbin and slot liners. By using a bobbin to control the positioning of the coil, a relatively high fill factor, such as greater than 55%, can be achieved for winding the coil around the teeth. At the same time, the slot liners can provide insulation to ensure that creepage distance and clearance requirements are met. The combination of the bobbin and the slot liners can thus provide the relevant insulation while also being able to achieve a relatively high fill factor.

[0116] Figure 17 An electric motor 400 is schematically shown, which includes any one of the first embodiment 10, the second embodiment 100, the third embodiment 200, and the fourth embodiment 300 of the stator assembly, and a rotor assembly 402. The rotor assembly 402 is an outer rotor assembly 402 that includes a plurality of permanent magnets (not shown). In use, a voltage is applied to the coils of the stator assemblies 10, 100, 200, 300 to generate a magnetic field, which in turn interacts with the permanent magnets to rotate the rotor assembly 402 relative to the stator assemblies 10, 100, 200, 300. Further details of the electric motor 400 are not relevant and are thus not described here for the sake of brevity. Although an outer rotor motor is shown here, it should be understood that an inner rotor motor utilizing the teachings discussed here is also conceivable.

[0117] Figure 18 A vacuum cleaner 500 including the electric motor 400 is schematically shown. The vacuum cleaner 500 includes a main unit 502, a rod 504, and a cleaning head 506.

[0118] Figure 19 schematically shows a cleaning head 506, which includes a housing 508, a brush bar 510, and an electric motor 400. The electric motor 400 is located within the brush bar 510 and is used to drive the brush bar 510 to move within the housing 508 during use. Further details of the cleaning head 506 are not relevant, and thus will not be described here for the sake of brevity.

[0119] Figure 20 Figure 20 schematically shows a hair care appliance 600 that includes an electric motor 400. Here, the electric motor 400 generates an air flow through the hair care appliance 600 during use.

[0120] Figure 21 Figure 21 schematically shows a fan assembly 700 that includes an electric motor 400. Here, the electric motor 400 generates an air flow through the fan assembly 700 during use.

[0121] Although specific examples and embodiments have been described thus far, it should be understood that these are merely illustrative and that various modifications can be made without departing from the scope of the invention as defined by the claims.

Claims

1. A stator assembly for an electric motor, the stator assembly comprising: A stator core including a plurality of teeth spaced apart to define slots; A coil wound around one of the plurality of teeth; A bobbin positioning the coil relative to the tooth; And A slot liner located within the slot.

2. The stator assembly according to claim 1, wherein, The bobbin includes a plurality of grooves, and the innermost layer of the coil is located within the plurality of grooves.

3. The stator assembly according to claim 1 or 2, wherein, The bobbin includes a retaining member for retaining the coil within the slot.

4. The stator assembly according to claim 3, wherein, The retaining member includes a plurality of guiding channels, and at least a portion of the coil is located within the plurality of guiding channels.

5. The stator assembly according to any one of the preceding claims, wherein The tooth includes an inner end, the bobbin includes an inner guiding surface located around the inner end of the tooth, the inner guiding surface includes guiding recesses, and at least a portion of the initial turns of the coil is located within the guiding recesses.

6. The stator assembly according to any one of the preceding claims, wherein, The plurality of teeth are spaced apart to define a plurality of slots, and the slot liner is located within adjacent slots on either side of the tooth.

7. The stator assembly according to claim 6, wherein, The slot liner includes a hole through which the tooth extends.

8. The stator assembly according to any one of the preceding claims, wherein, The slot liner is formed of an elastically deformable material.

9. The stator assembly according to any one of the preceding claims, wherein, The slot liner overhangs the ends of the corresponding adjacent slots on either side of the tooth.

10. The stator assembly according to any one of the preceding claims, wherein, The stator assembly has a width of no more than 100 mm.

11. The stator assembly according to any one of the preceding claims, wherein, The stator core includes a yoke, and the teeth are separate components attached to the yoke.

12. The stator assembly according to any one of the preceding claims, wherein, The tooth includes a body and an outer tooth tip extending outwardly from the outer end of the body.

13. The stator assembly according to any one of the preceding claims, wherein, The tooth includes a body and an inner tooth tip extending outwardly from the inner end of the body.

14. The stator assembly according to any one of the preceding claims, wherein, The bobbin includes a first bobbin portion located around a first portion of the tooth and a second bobbin portion located around a second portion of the tooth, the first bobbin portion and the second bobbin portion including separate components attached to each other.

15. The stator assembly according to claim 14, wherein, The first bobbin portion and the second bobbin portion overlap each other at an interface between the first bobbin portion and the second bobbin portion.

16. The stator assembly according to claim 14 or 15, wherein, The interface between the first bobbin portion and the second bobbin portion is located at the axial end of the tooth.

17. The stator assembly according to any one of the preceding claims, wherein, The slot liner is located between the bobbin and a portion of the tooth.

18. The stator assembly according to any one of claims 1 to 13, wherein, The bobbin includes a first bobbin portion located at a first end of the tooth and a second bobbin portion located at a second end of the tooth opposite the first end of the tooth, the first bobbin portion and the second bobbin portion including separate components.

19. The stator assembly according to claim 18, wherein, The tooth includes a recess, and the first bobbin portion includes a protrusion received within the recess.

20. The stator assembly according to any one of claims 1 to 10, wherein, The stator core includes a yoke, and the teeth are integrally formed with the yoke.

21. The stator assembly according to claim 20, wherein, The bobbin includes a hole, and the outer end of the tooth includes an edge that does not cover the perimeter of the hole.

22. The stator assembly according to claim 20 or 21, wherein, The bobbin includes a one-piece component.

23. The stator assembly according to claim 20, wherein, The bobbin includes a first bobbin portion located at a first end of the tooth and a second bobbin portion located at a second end of the tooth opposite the first end of the tooth, the first bobbin portion and the second bobbin portion including separate components.

24. The stator assembly according to claim 23, wherein, The first bobbin portion and the second bobbin portion each include a respective first member corresponding to the shape of the yoke and a respective second member corresponding to the shape of the tooth.

25. An electric motor comprising the stator assembly according to any one of the preceding claims.

26. A vacuum cleaner comprising the electric motor according to claim 25.

27. A cleaning head for a vacuum cleaner, the cleaning head comprising a rotatable member and an electric motor as claimed in claim 25, the electric motor being configured to rotate the rotatable member.

28. A fan assembly comprising an electric motor as claimed in claim 25.

29. A method comprising: providing a bobbin including a first hole; winding a coil around the bobbin; providing a slot liner including a second hole; providing a stator core including a plurality of teeth spaced apart to define a plurality of slots; passing one of the plurality of teeth through the second hole such that the slot liner is located in adjacent slots on either side of the tooth; and passing the tooth through the first hole such that the bobbin is located around the tooth and such that at least a portion of the bobbin and at least a portion of the coil are located in adjacent slots on either side of the tooth.

30. A method comprising: providing stator teeth; providing a slot liner including a first hole; passing the stator teeth through the first hole such that the slot liner is located along the stator teeth; providing a first bobbin portion and a second bobbin portion separate from the first bobbin portion; connecting the first bobbin portion to the second bobbin portion such that the first bobbin portion and the second bobbin portion are located around the stator teeth and holding the slot liner in place relative to the stator teeth; winding the bobbin to form a stator tooth subassembly; and fixing the stator tooth subassembly to a yoke of the stator core.

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