Annular support member

Abstract

An annular support member 30, formed from a non-electrically conductive material, for a stator assembly 10. The annular support member comprises an outer 32 and inner 31 circumferential wall arranged

Description

TECHNICAL FIELD The present disclosure relates to an annular support member for a stator assembly. Aspects of the invention relate to an annular support member, to a stator assembly comprising said annular support member, to an electric vehicle comprising said stator assembly and to a method of manufacturing a stator assembly. BACKGROUND It is known to provide a stator assembly comprising a stator core and a plurality of conductive (e.g., copper) windings which are inserted into respective stator slots provided in the stator core. Once inserted, the electrical windings are typically pinned in position before undergoing a flaring operation. However, it has been found that known solutions for pinning electrical windings are poorly suited for applications where one or more additional components (e.g., cooling manifolds) are provided at an end surface of the stator core and can often increase the axial length of the stator assembly. Furthermore, when using known solutions, it can also be difficult to transfer resin into the respective stator slots during manufacture of the stator assembly and hence the stator slot “fill factors” achieved by known solutions are often less than is typically desirable. It is therefore an aim of the present invention to address one or more of the aforementioned disadvantages associated with known solutions. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide an annular support member, a stator assembly comprising said annular support member, an electric vehicle comprising said stator assembly and a method of manufacturing a stator assembly as claimed in the appended claims. According to an aspect of the present invention there is provided an annular support member for a stator assembly, said annular support member being formed from a non-electrically conductive material and comprising: an outer circumferential wall; an inner circumferential wall arranged concentrically with the outer circumferential wall; and a plurality of members extending radially between the inner and outer circumferential walls, wherein the plurality of members are disposed at regular intervals about the circumference of the annular support member between the inner and outer circumferential walls, wherein the annular support member further comprises a plurality of apertures, each aperture being defined between adjacent members of the plurality of members; and wherein the plurality of apertures are configured for receiving a plurality of electrical stator windings during use. Advantageously, the annular support member according to the claimed invention provides a bearing surface which helps to constrain radial movement of the electrical stator windings during “twist and flare”. Optionally, the plurality of members may each comprise an apexed surface having a pair of angled wall portions, wherein each angled wall portion is configured for conveying a fluid into at least one of the plurality of apertures. Advantageously, the provision of members having an apexed surface helps to aid resin transfer into the respective apertures during manufacture of the stator assembly thereby resulting in better resin impregnation of the electrical stator windings. Optionally, the inner and / or outer circumferential wall may comprise an aperture facing surface, and a portion of said aperture facing surface proximal to a rim of the annular support member may be angled towards the plurality of apertures. Advantageously the provision of an aperture facing surface which is angled towards the plurality of apertures helps to further aid resin transfer into the respective apertures during manufacture of the stator assembly thereby resulting in better resin impregnation of the electrical stator windings. Optionally, the aperture facing surface of the inner and / or outer circumferential wall may further comprises a flared portion provided proximal to a base of the annular support member. Advantageously, the provision of a flared portion provided at the aperture facing surface of the inner and / or outer circumferential wall helps to facilitate removal of the annular support member from a tool mould after manufacture. Optionally, the inner and / or outer circumferential wall may comprise a flared portion. Optionally, the annular support member may further comprise at least one fixation tab extending radially away from an outer surface of the annular support member. Advantageously, the at least one fixation tab is configured for cooperating with a corresponding surface of the stator assembly so as to constrain axial movement of the annular support member during use. This feature thereby helps to ensure that the annular support member remains in position when the stator assembly is inverted for “twist and flare” operations. Optionally, the at least one fixation tab may extend radially away from an outer surface of the outer circumferential wall. Optionally, the annular support member may comprise a plurality of fixation tabs, said fixation tabs being disposed at regular intervals about the outer surface of the annular support member. Optionally, the annular support member may further comprise an axial groove provided at a radially innermost annular surface of the annular support member, said axial groove extending the full axial length ofthe annular support member. Advantageously, the provision of said axial groove enables a user to easily confirm when the annular support member has been received (and is in contact with) an end surface ofthe stator assembly during manufacture ofthe stator assembly. Optionally, the axial groove may be provided at the aperture facing surface ofthe inner circumferential wall. Optionally, the annular support member may be formed from a polymeric material, optionally a nylon polyamide material, and more optionally PA66. Optionally, each ofthe plurality of apertures may be configured to receive at least six electrical statorwindings. According to another aspect ofthe invention, there is provided a stator assembly for an electric machine, the stator assembly comprising: a stator core comprising a plurality of longitudinally extending winding slots, wherein a plurality of electrical stator windings are secured within each ofthe longitudinally extending winding slots via a resin; and the annular support member according to the previous aspect ofthe invention, said annular support member being provided at an end surface ofthe stator core, wherein each aperture ofthe annular support member is coaxially aligned with a respective one of the slots provided in the stator core, and wherein each aperture ofthe annular support member is configured to receive at least some ofthe plurality of electrical stator windings housed within the longitudinally extending winding slots provided in the stator core. Optionally, the plurality of apertures may be configured so as to promote the transfer of resin, via capillary action, into the plurality of winding slots ofthe stator core during manufacture ofthe stator assembly. Advantageously, by configuring the plurality of apertures to promote the transfer of resin, via capillary action, into the plurality of slots, greater levels of resin fill can be achieved when compared to known methods. Optionally, the stator assembly may further comprise a cooling manifold provided at an end surface of the stator core for conveying coolant to or from one or more cooling passageways distributed through the stator core. Optionally, the cooling manifold may comprise an annular body defining a central cavity, and the annular support member may be provided within the central cavity of the cooling manifold. Advantageously, providing the annular support member within a central cavity of the cooling manifold provides a bearing surface which helps to constrain radial movement of the electrical stator windings during “twist and flare” without increasing the axial length of the stator assembly. Optionally, the stator assembly may comprise a first (drive) end for coupling to a transmission arrangement of a vehicle drive unit and a second (non-drive) end provided opposite to the first (drive) end, and the annular support member, and optionally the cooling manifold, may be provided at the second (non-drive) end of the stator assembly. Optionally, the stator core may be defined by a stator lamination stack. Optionally, the plurality electrical stator windings may be a plurality of hairpin wires. According to yet another aspect of the invention, there is provided an electric vehicle (e.g. a battery electric vehicle) comprising the stator assembly according to the previous aspect of the invention. According to a further aspect of the invention, there is provided a method of manufacturing a stator assembly comprising the steps of: a) locating a plurality of electrical stator windings within a respective slot provided in a stator core, wherein the plurality of electrical stator windings are arranged such that the respective ends of the electrical stator windings protrude beyond an end surface of the stator core; b) applying an annular support member onto the end surface of the stator core such that the respective ends of the electrical stator windings extend through a corresponding aperture provided in the annular support member; and c) introducing a resin between the plurality of electrical stator windings and an inner surface of the slot via the aperture provided in the annular support member so as to consolidate the plurality of electrical stator windings within the slot. Optionally, a plurality of slit-like channels may be defined in the gaps between the plurality of electrical stator windings, and step c) may comprise applying the resin onto the respective ends of the plurality of electrical stator windings and the resin being conveyed via a capillary action along said slit-like channels into the respective slot provided within the stator core. Advantageously, it has been found that using the capillary effect to “pull” resin along the slit-like channels defined by the gaps provided between adjacent stator windings and into the slot can help to further improve resin fill. Optionally, the method may further comprise, between steps b) and c), applying a bending force onto the respective ends of the plurality of electrical stator windings so as to cause the ends of the plurality of electrical stator windings to flare outwardly away from the slot and / or aperture within which the plurality of electrical stator windings are received. Optionally, the plurality of electrical stator windings may be bent in alternating directions. Optionally, the plurality of electrical stator windings may be bent in alternating circumferential directions. Advantageously, bending the plurality of electrical stator windings in alternating directions helps to minimise the amount of torque being applied onto the stator assembly during “twist and flare”. Optionally, the bending force applied onto the respective ends of the electrical stator windings may be applied in a direction which is transverse to an axial direction of the electrical stator windings. Optionally, the method may further comprise rotating the stator assembly by approximately 180 degrees such that the stator assembly is in an inverted orientation. Optionally, the method may further comprise, prior to step c), rotating the stator assembly by approximately 180 degrees so as to return the stator assembly to a non-inverted orientation. Optionally, the resin may be a heat-curable resin. According to a still further aspect of the invention, there is provided an annular support member for a stator assembly, said annular support member being formed from a non-electrically conductive material and comprising: an outer circumferential wall; an inner circumferential wall arranged concentrically with the outer circumferential wall; and a plurality of members extending radially between the inner and outer circumferential walls, wherein the plurality of members are disposed at regular intervals about the circumference of the annular support member between the inner and outer circumferential walls, and wherein the annular support member further comprises a plurality of apertures, each aperture being defined between adjacent members of the plurality of members. The term “resin” is defined herein to mean any natural or synthetic compound consisting of non-crystalline or viscous liquid substance. The term “non-electrically conductive” is defined herein to a mean a material having a resistivity equal to or greater than 1x108 ohm-meters (Q.m). Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in anyway and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a top- or end-view of a stator assembly according to an embodiment of the present invention; Figure 2 shows schematically a partial cross-sectional side-view of the stator assembly of Figure 1; Figure 3 shows a partial cross-sectional side-view of the stator assembly illustrated in Figure 1 in which a cooling manifold and an annular support member of the stator assembly are visible; Figure 4 shows a perspective view of the annular support member of the stator assembly illustrated in Figure 3; Figure 5 shows a vehicle comprising the stator assembly illustrated in Figures 1 to 3; Figure 6 shows a block-diagram depicting a method of manufacturing a stator assembly according to an embodiment of the present invention; Figure 7 shows a top-view of the stator assembly in which respective electrical windings are being bent (or flared) in alternating circumferential directions; and Figure 8 shows a view as Figure 3 in which a resin is being applied into respective winding slots provided in the stator core. DETAILED DESCRIPTION Examples of the present disclosure relate to a stator assembly. In particular, examples of the present invention relate to a stator assembly for an electric machine. Such an electric machine may be of a synchronous type or asynchronous type, for example a permanent magnet synchronous motor. Non-limiting examples will now be described with reference to accompanying Figures 1 to 8. Referring to Figures 1 and 2, the stator assembly 10 has an annular stator core 12. The stator core 12 has a cylindrical inner channel 14, which defines a central stator axis 16. The cylindrical inner channel 14 extends in a direction parallel to the central stator axis 16 from a first (drive) end of the stator core 12 to a second (nondrive) end of the stator core 12, said second end being provided opposite to the first end. The stator core 12 has a plurality of winding slots 22 which extend in a longitudinal direction between the first and second ends of the stator core 12 (i.e., in a direction parallel to the central stator axis 16) for supporting a plurality of electrical stator windings 150. In the illustrated embodiment, the plurality of electrical stator windings 150 are provided as a plurality of flat, copper bars (also known as hairpin wires). For simplicity, the electrical stator windings 150 are illustrated in Figure 1 in only one winding slot 22. The stator core 12 also includes a plurality of stator teeth 24 between which the plurality of windings slots 22 are defined. In other words, the winding slots 22 are interspersed between the stator teeth 24 in a circumferential direction about the stator core 12. Both the plurality of winding slots 22 and the plurality of stator teeth 24 extend from the first end to the second end of the stator core 12. The stator assembly 10 is intended for use in an electric machine 100, as illustrated in cross sectional view in Figure 1, where the electric machine 100 includes the stator assembly 10 and a rotor 112. The rotor 112 is configured to fit within the cylindrical inner channel 14 of the stator core 12 with a small air gap 26 therebetween. The outside surface of the rotor 112 provides a surface concentric with a circumference of the cylindrical inner channel 14, such that as the rotor 112 rotates within the cylindrical inner channel 14 of the stator core 12, a consistent air gap 26 is maintained between the rotor 112 and the stator core 12. In the illustrated embodiment, the electrical machine 100 comprises forty-eight winding slots 22, eight rotor poles and six electrical stator windings 150 provided within each winding slot 22 (so two-hundred and eightyeight electrical stator windings in total). However, it shall be appreciated that other combinations of winding slot numbers, rotor pole numbers and electrical stator winding numbers may be used. As shown in Figure 1, the electrical machine 100 has a housing 102 surrounding the stator assembly 10. In some embodiments the housing 102 is a cylindrical housing (as illustrated in Figure 1), though it will be understood that the stator core 12 may have a non-circular cross section, in particular where the outer form of the stator core 12 is oblate or has projections thereon, such that the housing 102 may be non-circular. The stator core 12 has a plurality of cooling passageways 28 which extend in a longitudinal direction (i.e., in a direction parallel to the central stator axis 16) through the stator core 12 away from the first end of the stator core 12. In particular, the cooling passageways 28 extend from the first end to the second end of the stator core 12. The cooling passageways 28 are distributed circumferentially about the stator core 12. In the illustrated arrangement, the stator core 12 is defined by a stator lamination stack 44. In other words, the stator core 12 is formed of a plurality of layers 44A, 44B (as illustrated most clearly in Figure 2). The layers 44A, 44B are stacked one atop the other to form the stator lamination stack 44, which extends from the first end 18 of the stator core 12 to the second end 20 of the stator core 12. The layers 44A, 44B may be stamped from sheet material (e.g., sheet metal), or formed via any other suitable process. In this way, a stator core 12 having a complex cross-sectional shape can be formed. The stator assembly 10 includes a bolting arrangement 46 which is configured to provide a clamping force to the stator lamination stack 44. This inhibits delamination (i.e., separation of layers 44A, 44B) in the stack 44 (e.g., during manufacturing). The bolting arrangement 46 includes a bolt 48 having a shaft 50 which extends through a bolt passageway 52 in the stator lamination stack 44. In particular, the illustrated bolt 48 extends the entire length of the bolt passageway 52 in order to facilitate a clamping force which acts on opposing ends of the stator lamination stack 44. Referring now to Figures 3 and 4, the stator assembly 10 also comprises an annular support member 30 which is provided at a radially inner part of an end surface 12a of the stator core 12, In the illustrated embodiment, the annular support member 30 is provided at the second (non-drive) end of the stator core 12. However, it shall be appreciated that in other embodiments, the annular support member 30 may be provided at the first end of the stator core 12. The annular support member 30 is formed from a non-electrically conductive material and has a pair of inner 31 and outer 32 circumferential walls which are arranged concentrically. In the illustrated embodiment, the annular support member 30 is formed from a nylon polyamide material such as polyamide 66 (or PA66). However, it shall be appreciated that in other embodiments, the annular support member 30 may be formed from other polymeric or non-polymeric materials. As shown in Figure 4, a plurality of members 33 extend radially between the inner 31 and outer 32 circumferential walls. The plurality of members 33 are disposed at regular intervals about the circumference of the annular support member 30 such that a plurality of apertures 34 are defined between the adjacent members 33. In other words, the plurality of apertures 34 are interspersed between the respective members 33 such that each adjacent pair of members 33 define a respective aperture 34 therebetween. The plurality of apertures 34 are each configured for receiving a plurality of the electrical stator windings 150 as is shown in Figure 3. More particularly, the annular support member 30 is arranged within the stator assembly 10 such that the plurality of apertures 34 are in coaxial alignment with the respective winding slots 22 provided in the stator core 12. As such, the respective ends of the electrical stator windings 150, which protrude beyond the end surface 12a of the stator core 12, can be received within the plurality of apertures 34 provided in the annular support member 30. It shall also be appreciated that in the illustrated embodiment, the number of apertures 34 disposed about the annular support member 30 corresponds to (i.e., is equal to) the number of winding slots 22 provided in the stator core 12. As mentioned above, in the illustrated embodiment, each winding slot 22 provided in the stator core 12 is configured to receive six electrical stator windings 150. As such, in the illustrated embodiment, each aperture 34 provided in the annular support member 30 is also configured for receiving at least six electrical stator windings 150. However, it shall be appreciated that in other embodiments, the plurality of apertures 34 may each be configured for receiving a different number of electrical stator windings 150. During use, the annular support member 30 is primarily configured for providing a bearing surface for the electrical stator windings 150 to help constrain radial movement of said electrical stator windings 150 during “twist and flare” of the electrical stator windings 150 as described in greater detail below. However, the plurality of apertures 34 also have a secondary function to promote consistent resin flow into the plurality of winding slots 22 during manufacture of the stator assembly 10. More particularly, the annular support member 30 of the present invention acts as a funnel during impregnation of the winding slots 22 helping to guide the resin into the respective winding slots 22 and thereby improving the stator slot “fill factor” achievable when manufacturing the stator assembly 10. Furthermore, when a plurality of stator windings 150 are received within the apertures 34 provided in the annular support member 30, the respective windings 150 become bunched together such that a plurality of slit-like channels 152a-care defined in the gaps between the adjacent electrical stator windings 150. As such, when a resin is applied onto the respective ends of the plurality of electrical stator windings 150 (during manufacture of the stator assembly 10) the capillary action of the slit-like channels 152a-c “draws” or “pulls” the resin along said channels 152a-c and into the winding slots 22 provided in the stator core 12 which helps to further improve the stator slot “fill factor” whilst also helping to reduce unwanted spillage of resin onto the end surface 12a of the stator core 12. Considering now the inner 31 and outer 32 circumferential walls in further detail, the inner circumferential wall 31 comprises a radially inner surface 31a (which is the radially innermost annular surface of the annularsupport member 30) and a radially outer surface 31b which faces towards, and partially defines, the plurality of apertures 34. As such, the radially outer surface 31b of the inner circumferential wall 31 can be considered as an “aperture-facing” surface. The radially outer surface 31b of the inner circumferential wall 31 comprises a flared portion 31c proximal to the base of the annular support member 30 (i.e., the end of the annular support member 30 which abuts against the end surface 12a of the stator core 12 during use) and an angled portion 31 d provided proximal to the rim of the annular support member 30 (i.e., the end of the annular support member 30 which is distal to its base against the stator core) which is angled inwardly from the rim towards the plurality of apertures 34. Similarly, the outer circumferential wall 32 also comprises a radially outer surface 32b (which is the radially outermost annular surface of the annular support member 30) and a radially inner surface 32a which faces towards, and partially defines, the plurality of apertures 34. As such, the radially inner surface 32a of the outer circumferential wall 32 can also be considered as an “aperture-facing” surface. As with the radially outer surface 31b of the inner circumferential wall 31, the radially inner surface 32b of the outer circumferential wall 32 also comprises a flared portion 32c proximal to the base of the annular support member 30 and an angled portion 32d provided proximal to the rim of the annular support member 30 which is angled towards the plurality of apertures 34. As shown in Figure 3, an upper portion of each aperture 34, which is defined by the pair of angled portions 31d, 32d, features a substantially V-shaped cross-sectional shape. In other words, at the upper portion of each aperture 34 (i.e., proximal to the rim), the width of said aperture 34 decreases in the direction of the stator core 12 which enables the annular support member 30 to act as a funnel for guiding resin into the winding slots 22 via the plurality of apertures 34. Meanwhile, a lower portion of each aperture 34 (proximal to the base), which is defined by the pair of flared portions 31c, 32c, features a substantially trapezoid cross-sectional shape. In other words, at the lower portion of each aperture 34 (i.e., proximal to the base), the width of said aperture 34 increases in the direction of the stator core 12 due to the flared shape of the aperture facing surfaces 31b, 32a. This aids removal of the annular support member 30 from a corresponding mould tool during manufacture of the annular support member (e.g., via injection moulding or the like). However, it shall be appreciated that in some embodiments, the flared and / or angled portions may be provided on the aperture-facing surfaces of the inner circumferential wall 31 only or the outer circumferential wall 32 only and hence, in some embodiments, the upper and / or lower portions of the plurality of apertures 34 may have different cross-sectional shapes. It shall also be appreciated that in some embodiments, the inner and / or outer circumferential walls 31, 32 may have other shapes and / or configurations. Referring back to Figure 4, in the illustrated embodiment, the plurality of members 33 also comprise an apexed surface proximal to the rim of the annular support member 30. Each apexed surface comprises a respective pair of wall portions 33a,b between which an apex 33c is defined. The pair of wall portions 33a,b are each angled towards a respective one of the apertures 34 to help further aid the transfer of resin into the winding slots 22 during manufacture of the stator assembly 10. As shown in Figure 4, the left-side wall portion 33a of each member 33 (looking from the axis 16 radially outwardly) is angled towards a respective aperture 34 provided on the left side of said member 33 and the right-side wall portion 33b is angled towards a respective aperture 34 provided on the right side of said member 33. As such, in the event that a fluid (e.g., resin) is poured onto one of the members 33 during manufacture of the stator assembly 10, the angled wall portions 33a,b help to convey said fluid into the respective apertures 34 where it can subsequently flow into the respective winding slots 22 provided in the stator core 12. In the illustrated embodiment, the annular support member 30 also comprises an axial groove 35 which is provided at the radially inner surface 31a of the inner circumferential wall 31. The axial groove 35 extends along the full length of the annular support member 30 (i.e., from the base to the rim) and is configured for providing a direct line-of-sight to the end surface 12a of the stator core 12 to enable a user to more easily determine when the base of the annular support member 30 is abutting against the end surface 12a of the stator core 10 during assembly. However, whilst in the illustrated embodiment the axial groove is provided at the radially inner surface 31a of the inner circumferential wall 31, it shall be appreciated that in other embodiments, the axial groove 35 may instead be provided in one of the aperture-facing surfaces 31b, 32a or may be provided in the radially outer surface 32b of the outer circumferential wall 32. It shall also be appreciated that in some embodiments, the axial groove 35 may be omitted. In the illustrated embodiment, the annular support member 30 also features a plurality of fixation tabs 36a-c which extend radially away from the radially outer surface 32b of the outer circumferential wall 32. The plurality of fixation tables 36a-c are disposed at regular intervals about the radially outer surface 32c and are configured for cooperating with a corresponding surface of the stator assembly 10 (as described in greater detail below) to constrain axial movement of the annular support member 30 during assembly and / or use. Referring back to Figure 3, in the illustrated embodiment, the stator assembly 10 also comprises a cooling manifold 70 which is provided at the end surface 12a of the stator core 12. The cooling manifold 70 has an annular body 72, which defines a central cavity 74, and a cooling channel 76 which is provided in the annular body 72 and extends circumferentially around the central cavity 74 for conveying fluid (e.g., coolant) to and / or from the respective cooling passageways 28 distributed through the stator core 12. In the illustrated embodiment, a pair of sealing elements 78a, 78b are also provided on the radially inner and outer sides of the cooling channel 76 so as to prevent fluid (e.g., coolant) from leaking out of the cooling channel 76 during use. As shown in Figure 3, the annular support member 30 is provided within the central cavity 74 of the cooling manifold 70 which allows the annular support member 30 to act as a bearing surface for constraining radial movement of the plurality of electrical windings during “twist and flare” of the electrical stator windings 150 without increasing the axial length of the stator assembly 10. That is, the cooling manifold supports the support member 30. Moreover, the cooling manifold is assembled after installation of the support member and can serve to clamp the support member in place by engagement with the tabs 36. The colloing manifold may be connected by means not shown to the stator core 12. However, it shall be appreciated that in other embodiments, the cooling manifold 70 may be omitted. The electrical machine 100 described above with reference to Figures 1 to 4 may provide the function of a motor and / or generator for operation in a vehicle 200. For example, Figure 5 illustrates a vehicle 200 having a first electric machine 100-1 for driving one or more front wheels of the vehicle 200 and a second electric machine 100-2 fordriving one or more rear wheels of the vehicle 200. In other embodiments, the vehicle 200 may comprise only a single electric machine 100, arranged or configured to drive one or more front wheels of the vehicle 200 or one or more rear wheels of the vehicle 200. At a vehicle axle the electric machine 100 may be arranged to drive both wheels, either directly or through other transmission components. In other arrangements there may be more than one electric machine 100 arranged to provide torque to a vehicle axle, for example, to provide torque vectoring functionality for the vehicle 200. Other arrangements may have one electric machine 100 arranged or configured to drive each wheel of the vehicle 200. The electric machine 100 comprised in the vehicle 200 may have a stator assembly 10 as described herein. For example, the electric machine 100 comprised in the vehicle 200 may be the electrical machine of Figure 1. As illustrated schematically in Figure 5, the electrical machine 100 may be part of a vehicle drive unit 160. For example, the vehicle drive unit may include a transmission arrangement, lubrication and cooling components, and / or power electronics, in addition to the electrical machine 100. In such examples, a first (drive) end of the stator assembly 10 may be configured for coupling to the transmission arrangement of the vehicle drive unit 160. In such examples, the stator assembly 10 may also comprise a second (non-drive) end provided opposite to the first (drive) end. It shall be appreciated that the first (drive) and second (non-drive) ends of the stator assembly 10 correspond to the first (drive) and second (non-drive) ends of the stator core 12. In the vehicle 200 of Figure 5, the first electric machine 100-1 is part of a first vehicle drive unit 160-1 fordriving front wheels of the vehicle 200, and the second electric machine 100-2 is part of a second vehicle drive unit 160-2 for driving rear wheels of the vehicle 200. As such, in the illustrated embodiment, the first and second vehicle drive units 160-1,160-2 are electric drive units (EDUs). The functioning of electrical machines 100 and electric drive units (EDUs) 160 is known, and so will not be described here in more detail. A method of manufacturing a stator assembly 10 according to an embodiment of the present invention shall now be described with reference to Figures 6 to 8. During a first step 300 of the method, the plurality of electrical stator windings 150 are first located within the respective winding slots 22 provided in the stator core 12 such that the respective ends of the plurality of electrical stator windings 150 protrude beyond an end surface 12a of the stator core 12. Although not shown in Figures 3 and 8, it shall be appreciated that when the plurality of electrical stator windings 150 are first located within the respective winding slots 22, the electrical stator windings 150 are substantially straight and hence are axially aligned with the respective winding slots 22. In other words, the plurality of electrical stator windings 150 are orientated substantially parallel to the central stator axis 16. Once the plurality of electrical stator windings 150 have been located within the winding slots 22, at step 310 the annular support member 30 is applied onto the end surface 12a of the stator core 12 such that the ends of the electrical stator windings 150 are received within, and extend through, the respective apertures 34 provided in the annular support member 30. As specified above, the annular support member 30 is applied onto the end surface 12a of the stator core 12 such that the plurality of apertures 34 disposed about the circumference of the annular support member 30 are coaxially aligned with the respective winding slots 22 provided in the stator core 12 thereby enabling the plurality of electrical stator windings 150 to be easily located within the corresponding apertures 34 disposed about the annular support member 30. The annular support member 30 is applied onto the end surface 12a ofthe stator core 12 until a bottom surface of the annular support member 30 (proximal to the base) abuts against the end surface 12a ofthe stator core 12 which can be confirmed by an operator by looking down the axial groove 35 provided at the radially inner surface 31a ofthe inner circumferential wall 31. Once the annular support member 30 has been applied onto the end surface 12a ofthe stator core 12, at step 320 the plurality of electrical stator windings 150 undergo a “twist and flare” operation as described in detail below. In particular, as shown in Figure 7, the “twist and flare” operation involves applying a bending force (illustrated by the horizontal arrows in Figure 7) onto the respective ends ofthe plurality of electrical stator windings 150 in a direction which is transverse to an axial direction ofthe electrical stator windings 150 so as to cause the respective ends ofthe plurality of electrical stator windings 150 to flare outwardly away from the winding slots 22 / apertures 34 within which the electrical stator windings 150 are received. In the illustrated embodiment, the respective ends ofthe plurality of electrical stator windings 150 are bent in alternating circumferential directions (illustrated by the horizontal arrows in Figure 7) with the respective ends ofthe first 150a, third 150c and fifth 150e electrical stator windings being bent in a first (right-hand orclockwise) direction and the respective ends ofthe second 150b, fourth 150d and sixth 150f electrical stator windings being bent in a second (left-hand or anti-clockwise) direction, opposite to the first direction. It has been found that bending the electrical stator windings 150 in alternating directions helps to reduce (or minimise) the amounts of torque being applied onto the stator assembly 10 during “twist and flare” ofthe electrical stator windings 150. However, it shall be appreciated that in other embodiments, the respective ends ofthe electrical stator windings 150 may be bent in different directions to those which are depicted in Figure 7. In some embodiments, the step of “twisting and flaring” the respective ends ofthe plurality of electrical stator windings 150 may also involve rotating the stator assembly 10 by approximately 180 degrees such that the stator assembly 10 becomes inverted. In other words, during step 320, the stator assembly may be placed in an inverted orientation such that the end surface 12a ofthe stator core 12 (upon which the annular support member 30 is received) is the lower-most surface ofthe stator core 12. Notably, the machinery which is typically used forbending the respective ends ofthe electrical stator windings 150 is very heavy and hence, by inverting the (relatively lighter) stator assembly 10 during step 320, the lifting of such machinery can be avoided. It shall also be appreciated that in embodiments in which the annular support member 30 comprises one or more fixation tabs 36 extending radially away from the radially outer surface 32b of the outer circumferential wall 32, as the stator assembly 10 becomes inverted, the one or more fixation tabs 36 will be urged into cooperating with the (now upper) surface 70a of the cooling manifold 70 thereby constraining axial movement of the annular support member 30. However, it shall be appreciated that in other embodiments in which the one or more fixation tabs 36 are omitted, the axial movement of the annular support member 30 may instead be constrained by other means during inversion of the stator assembly 10 (such as by the frictional forces acting between corresponding surfaces of the annular support member 30 and the cooling manifold 70). Finally, once the “twist and flare” operation has been performed (and optionally once the stator assembly 10 has been returned to its original, non-inverted orientation), the plurality of electrical windings 150 are consolidated within the winding slot 22 provided in the stator core 12 at step 330 via introducing a resin R between the plurality of electrical stator windings 150 and an inner surface of each winding slot 22, via the apertures 34 provided in the annular support member 30. More particularly, as illustrated in Figure 8, the resin R is applied onto the respective ends of the plurality of electrical stator windings 150 such that the capillary action of the slit-like channels 152 (defined in the gaps between the respective electrical stator windings 150) “draws” or “pulls” the resin R along the aforementioned channels 152 and into the winding slots 22 provided in the stator core 12. It has been found that using such a method to “pull” or “draw” resin (R) into the winding slots 22 helps to improve the stator slot “fill factor” and also helps to reduce unwanted spillage of resin onto the end surface(s) of the stator core. However, it shall be appreciated that in other embodiments, the resin may be applied via other methods (such as by pouring the resin directly into the respective apertures 34). Once the resin R has been introduced into the winding slots 22 (as shown in Figure 8), it is then cured to complete the consolidation process. As specified above, in the illustrated embodiment the resin R is a heat-curable resin and hence the resin R may be cured via simply heating the stator assembly 10 to a requisite temperature or, in some cases, by allowing the stator assembly 10 to sit at room (or ambient) temperature for an extended period of time until the resin R has solidified. Alternatively, in other embodiments, the curing step may instead be performed by applying a curing agent into the respective winding slots 22 so as to cause the resin R to solidify or may involve applying UV light to the resin R in cases where a UV-curable resin has been used. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. An annular support member for a stator assembly, said annular support member being formed from a non-electrically conductive material and comprising:an outer circumferential wall;an inner circumferential wall arranged concentrically with the outer circumferential wall; anda plurality of members extending radially between the inner and outer circumferential walls, wherein the plurality of members are disposed at regular intervals about the circumference of the annular support member between the inner and outer circumferential walls,wherein the annular support member further comprises a plurality of apertures, each aperture being defined between adjacent members of the plurality of members; andwherein the plurality of apertures are configured for receiving a plurality of electrical stator windings during use.

2. The annular support member according to claim 1, wherein the plurality of members each comprise an apexed surface having a pair of angled wall portions, and wherein each angled wall portion is configured for conveying a fluid into at least one of the plurality of apertures.

3. The annular support member according to claims 1 or 2, wherein the inner and / or outer circumferential wall comprises an aperture facing surface, and wherein a portion of said aperture facing surface proximal to a rim of the annular support member is angled towards the plurality of apertures.

4. The annular support member according to claim 3, wherein the aperture facing surface of the inner and / or outer circumferential wall further comprises a flared portion provided proximal to a base of the annular support member.

5. The annular support member according to any preceding claim, wherein the annular support memberfurther comprises at least one fixation tab extending radially away from an outer surface of the annular support member.

6. The annular support member according to any preceding claim, wherein the annular support memberfurther comprises an axial groove provided at a radially innermost annular surface of the annular support member, said axial groove extending the full axial length of the annular support member.

7. A stator assembly for an electric machine, the stator assembly comprising:a stator core comprising a plurality of longitudinally extending winding slots, wherein a plurality of electrical stator windings are secured within each of the longitudinally extending winding slots via a resin; andthe annular support member according to any preceding claim, said annular support member being provided at an end surface of the stator core,wherein each aperture of the annular support member is coaxially aligned with a respective one of the slots provided in the stator core, andwherein each aperture of the annular support member is configured to receive at least some of the plurality of electrical stator windings housed within the longitudinally extending winding slots provided in the stator core.

8. The stator assembly according to claim 7, wherein the plurality of apertures are configured so as to promote the transfer of resin, via capillary action, into the plurality of winding slots of the stator core during manufacture of the stator assembly.

9. The stator assembly according to claims 7 or 8, wherein the stator assembly further comprises a cooling manifold provided at an end surface of the stator core for conveying coolant to or from one or more cooling passageways distributed through the stator core, wherein the cooling manifold comprises an annular body defining a central cavity, and wherein the annular support member is provided within the central cavity of the cooling manifold.

10. The stator assembly according to any of claims 7 to 9, wherein the stator assembly comprises a first end for coupling to a transmission arrangement of a vehicle drive unit and a second end provided opposite to the first end, and wherein the annular support member, and optionally the cooling manifold, are provided at the second end of the stator assembly.

11. An electric vehicle comprising the stator assembly according to any of claims 7 to 10.

12. A method of manufacturing a stator assembly comprising the steps of:a) locating a plurality of electrical stator windings within a respective slot provided in a stator core, wherein the plurality of electrical stator windings are arranged such that the respective ends of the electrical stator windings protrude beyond an end surface of the stator core;b) applying an annular support member onto the end surface of the stator core such that the respective ends of the electrical stator windings extend through a corresponding aperture provided in the annular support member; andc) introducing a resin between the plurality of electrical stator windings and an inner surface of the slot via the aperture provided in the annular support member so as to consolidate the plurality of electrical stator windings within the slot.

13. The method according to claim 12, wherein a plurality of slit-like channels are defined in the gaps between the plurality of electrical stator windings, and wherein step c) comprises applying the resin onto the respective ends of the plurality of electrical stator windings and the resin being conveyed via a capillary action along said slit-like channels into the respective slot provided within the stator core.

14. The method according to claims 12 or 13, wherein the method further comprises, between steps b) and c), applying a bending force onto the respective ends of the plurality of electrical stator windings so as tocause the ends ofthe plurality of electrical stator windings to flare outwardly away from the slot and / or aperture within which the plurality of electrical stator windings are received.

15. The method according to claim 14, wherein the plurality of electrical stator windings are bent in5 alternating directions.Application No: GB2408810.6Examiner:Jonathan MarlowClaims searched: 1-11Date of search: 19 November 2024Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-4, 7-11 US 2016 / 0043605 Al (MIZUTANI et al.) Figures 2, 7, 9, 10 &13 and paragraphs [0009], [0042], [0053] &[0056], X 1-4, 7-11 JP 2018143066 A (TOYOTA MOTOR) Figures 1 &3 and paragraphs [0015], [0017] &[0021], X 1,5 CN 113557648 B (YU RENWEI) Figures 1, 2 &13 and paragraphs [0045]-[0046j. X 1,6 CN 210167882 U (NANJING AMTF ELECTRONIC) Figures 6 &11 and paragraph [0035], X 1 US 2022 / 0385152 Al (ENGELHARDT et al.) Figures 2 &3 and paragraph [0025], v A 1 WO 2020 / 196182 Al (DAIKIN IND) Figure 2.Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if combined with one or more other documents of same category. P Document published on or after the declared priority date but before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From H02K 0015 / 00 01 / 01 / 2006 TjnOIZ rlUZix 0003 / 38 01 / 01 / 2006 H02K 0003 / 46 01 / 01 / 2006 H02K 0015 / 12 01 / 01 / 2006Application No:     GB2408810.6Examiner: Jonathan MarlowClaims searched: 12-15Date of search: 26 March 2025Patents Act 1977Further Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance v A X X 12-15 12-15 12-15 US 2016 / 0043605 Al (MIZUTANI et al.) Figures 1, 2 &7 and paragraphs [0046] &[0053], JP 2018143066 A (TOYOTA MOTOR) Figures 1 &2 and paragraphs [0015], [0016] &[0021], US 2018 / 0152071 Al (MASUGI et al.) Figures 1, 4 &5 and paragraphs [0004], [0023] &[0032],Categories: X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if combined with one or more other documents of same category. P Document published on or after the declared priority date but before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:Search of GB, EP, WO &US patent documents classified in the following areas of the UKCX :Worldwide search of patent documents classified in the following areas of the IPC____________H02K_________________________________________________The following online and other databases have been used in the preparation of this search reportSEARCH-PATENTInternational Classification:Subclass Subgroup Valid From H02K 0015 / 00 01 / 01 / 2006 H02K 0003 / 38 01 / 01 / 2006 WCiOIZ rlUZix 0003 / 46 01 / 01 / 2006 H02K 0015 / 12 01 / 01 / 2006

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