Stator assembly

Abstract

A stator assembly (1) of an axial flux electric machine is described. The stator assembly (1) comprises a plurality of stator coils (4) and a plurality of core segments (2) arranged circumferentially to define segmented stator cores (3). Each core segment (2) comprises a tooth portion (2a) extending in the axial direction and adapted to mount a respective stator coil (4). The stator core (3) may also be non-segmented in which the plurality of tooth portions are arranged in the circumferential direction. Adjacently mounted stator coils (4) are spaced apart by a substantially trapezoidal gap. The stator assembly (1) further comprises a plurality of stator coil holders (10). Each holder (10) is received in a respective gap between a pair of adjacently mounted stator coils (4) and its position in the radial direction is independently adjustable. Each holder (10) comprises at least one channel for receiving a cooling fluid (e.g., cooling air or a suitable cooling liquid, such as water or propylene glycol). Each retainer (10) further comprises a pair of contact surfaces spaced apart in the circumferential direction. Each holder (10) is adapted to apply a contact pressure to a respective pair of adjacently mounted stator coils (4) via a contact surface.

Description

Technical Field

[0001] This invention relates to stator assemblies, and more particularly to stator assemblies for axial flux motors (e.g., motors or generators). Summary of the Invention

[0002] This invention provides a stator assembly for an axial flux motor (e.g., a motor or generator), the stator assembly comprising: Multiple stator coils; A stator core comprising a plurality of toothed portions arranged circumferentially, each toothed portion extending axially and adapted to mount a corresponding stator coil, wherein adjacent stator coils are spaced apart by substantially trapezoidal gaps; and Multiple stator coil retainers, each retainer being received in a corresponding gap between a pair of adjacent mounted stator coils, and having a position that can be independently adjusted in the radial direction relative to the stator core, so that the contact pressure applied independently by the adjacent retainers to each mounted stator coil, for example during the assembly process.

[0003] Axial flux motors (e.g., motors or generators) may include a stator assembly and a rotor assembly as described above. Magnetic flux flows through the rotor assembly in the axial direction (i.e., along the direction parallel to the axis of rotation of the rotor assembly). The rotor assembly may have any suitable structure. Depending on the rotor structure, the motor may function as a synchronous or asynchronous / induction motor. For example, the rotor assembly may be a wound rotor with rotor windings, a squirrel-cage rotor with a plurality of radially extending conductive bars (the plurality of radially extending conductive bars are circumferentially spaced around the rotor assembly and electrically connected between a pair of radially spaced conductive rings (or “short-circuit rings”), a permanent magnet rotor with a plurality of permanent magnets (the plurality of permanent magnets are circumferentially spaced around the rotor assembly—e.g., on an annular surface of the rotor assembly or within the rotor assembly), or a salient pole / resistance rotor assembly with a plurality of salient poles circumferentially spaced around the rotor assembly.

[0004] Each retainer may include a pair of contact surfaces spaced apart in the circumferential direction. Each retainer is adapted to apply contact pressure to a corresponding pair of adjacently mounted stator coils via the contact surfaces. The contact pressure helps to hold the stator coils on the stator core. In particular, the contact pressure applied via the contact surfaces prevents movement of adjacent stator coils in the circumferential direction and also helps to limit movement in the axial direction. In practice, the contact pressure alone may not be sufficient to prevent movement of adjacent stator coils in the axial direction, and therefore each retainer will preferably also include at least one retaining feature (described in more detail below) adapted to prevent movement of adjacent stator coils in the axial direction. Each stator coil is securely held between the retaining features of the adjacent retainers and the opposing surfaces that fix the stator core. It will be understood that the stator coils should be held against the electromagnetic forces generated during motor operation. This allows for fretting if components become loose, and therefore they need to be properly secured. The contact pressure applied by each retainer also improves the cooling of the stator coils to ensure good thermal coupling between the contact surfaces of the retainers and the facing surfaces of each stator coil. In particular, each retainer may include at least one channel for receiving cooling fluid (e.g., cooling air or cooling liquid) to allow heat from the stator coils to be transferred to the cooling fluid to cool the stator coils.

[0005] The contact pressure applied to adjacent stator coils can be adjusted or changed by adjusting the position of each retainer in the radial direction, for example, during the assembly process. Once the desired contact pressure is achieved by adjusting the position of each retainer, the retainers are fixed in place relative to the stator core (e.g., by tensioning one or more mechanical fasteners and / or engaging one or more stops) so that they do not move during normal operation of the motor. All of this is described in more detail below.

[0006] Each contact surface can directly contact the facing surface of a corresponding coil in a pair of adjacent stator coils. Therefore, contact pressure can be applied directly to the facing surface of the adjacent stator coil through the contact surface of each retainer. However, in some arrangements, one or more insert members (e.g., gaskets) may be positioned between the contact surface and the facing surface of the adjacent stator coil, i.e., so that contact pressure is applied indirectly to the facing surface through the insert member(s). At least a portion of each contact surface can directly contact the facing surface of a corresponding coil in a pair of adjacent stator coils, and optionally, a portion of each contact surface may contact the insert member, or may not contact either the facing surface or the insert member. In another arrangement, substantially the entire contact surface can directly contact the facing surface of the corresponding stator coil or the surface of the insert member.

[0007] Each stator coil may include a pair of substantially parallel side sections defining an outer-facing surface of the stator coil that contacts a contact surface or insertion member of a corresponding retainer. A first side section of each stator coil may define a first facing surface that contacts a contact surface or first insertion member of an adjacent first retainer, and a second side section of each stator coil may define a second facing surface that contacts a contact surface or second insertion member of an adjacent second retainer. The side sections of each stator coil may extend substantially radially—along the radial direction of the stator assembly, but not necessarily along its radius. The facing surfaces of each stator coil may also extend substantially radially. Each stator coil may include a first end section extending at a first end of the stator coil between the first and second side sections; and a second end section extending at a second opposite end of the stator coil between the first and second side sections. For example, the first end section may be arranged at a radially outer portion of the stator core, and the second end section may be arranged at a radially inner portion of the stator core, or vice versa. For example, the first end section and the second end section may be curved. Each stator coil may include an internal gap within the side section and the end section, in which a corresponding tooth portion of the stator core is received, so that the stator coil extends around the tooth portion when properly mounted.

[0008] Individual stator coils are typically electrically interconnected to define stator windings. In particular, for example, stator coils may be interconnected to define centralized or distributed stator windings.

[0009] The stator windings may be electrically connected to, for example, a power converter for supplying power to the stator windings to operate the motor. The power converter may be electrically connected to, for example, a power grid or power grid, and may be used to control the rotational speed and / or torque of the motor in a known manner.

[0010] Each tooth portion may include a pair of substantially parallel side surfaces extending substantially radially, and a pair of end surfaces extending substantially circumferentially (i.e., along the circumferential direction of the stator assembly). When viewed in the axial direction, the tooth portion may have a substantially rectangular cross-section. The side surfaces of each tooth portion can be used to mount and support a corresponding stator coil. In other words, each stator coil may be positioned on a corresponding tooth portion, wherein the inner surfaces of the first and second side sections contact or are supported by the facing side surfaces of the tooth portion. If the end surfaces of each tooth portion are substantially parallel, and the end sections of the corresponding stator coil are curved, a gap or void may exist between the inner surface of each end section and the facing end surfaces of the tooth portion. Alternatively, the end surfaces of each tooth portion may be curved to better support the curved end surfaces on which the stator coils are mounted.

[0011] The stator core may include a base portion from which each tooth extends axially. The base portion may include a first planar surface from which each tooth portion extends; and a second planar surface. The first and second planar surfaces may be substantially parallel and may have a normal extending in the axial direction, i.e., the normal is parallel to the longitudinal axis of the stator assembly. The first and second planar surfaces may be substantially annular.

[0012] The stator core may be a segmented stator core. In particular, the stator assembly may include multiple core segments arranged circumferentially to define the segmented stator core. Each core segment may include a toothed portion that extends axially and is adapted to mount a corresponding stator coil.

[0013] Each core segment may include a base portion. A toothed portion may extend axially from the base portion. The base portion of each core segment may include a first planar surface and a second planar surface from which the toothed portion extends. The first and second planar surfaces may be substantially parallel and may have a normal extending in the axial direction, i.e., the normal is parallel to the longitudinal axis of the stator assembly. The base portion of each core segment may include a pair of side surfaces spaced apart in the circumferential direction and extending substantially along the radius of the stator core. The base portion of each core segment may also include a pair of end surfaces spaced apart in the radial direction, for example, a first end surface disposed at a radially outer portion of the stator core and a second end surface disposed at a radially inner portion of the stator core, or vice versa. When viewed in the axial direction, the base portion of each core segment may have a substantially trapezoidal cross-section, for example, wherein the radially inner end surface of each base portion is shorter in the circumferential direction than the radially outer end surface. Each side surface may contact a facing side surface of an adjacent core segment. In other words, core segments can be assembled together, with the side surfaces of their respective base portions in contact with each other. In another arrangement, core segments can be assembled together, with the side surfaces of their respective base portions spaced apart from each other by gaps or insert members positioned between adjacent core segments. The second side surface of the base portion of a first core segment can be arranged next to the first side surface of the base portion of an adjacent second core segment, the second side surface of the base portion of a second core segment can be arranged next to the first side surface of the base portion of an adjacent third core segment, and so on, until the second side surface of the base portion of the nth core segment can be arranged next to the first side surface of the base portion of a first core segment, where n is an integer corresponding to the total number of core segments. Depending on the overall size and design of the motor, the stator core can be assembled from any suitable number of core segments.

[0014] Each core segment can be mounted to an annular stator support of the stator assembly. The stator support can also be segmented, i.e., formed by two or more support segments assembled together in any suitable manner. For example, the support segments can be connected using multiple mechanical fasteners (e.g., threaded fasteners such as bolts or screws). The stator support may have a first annular surface and a second opposing annular surface. The stator support may have a laminated or solid structure.

[0015] Each core segment may have at least one engagement profile, and the first annular surface of the stator support (i.e., the surface facing the core segment) may include a plurality of circumferentially spaced corresponding engagement profiles. For example, each core segment may have one or more dovetail or T-shaped profiles, and the stator support may have a plurality of corresponding dovetail or T-shaped profiles in its first annular surface. In one arrangement, each core segment may have one or more protrusions with engagement profiles, and the stator support may have a plurality of recesses with corresponding engagement profiles, wherein each recess receives a protrusion of a corresponding core segment. One or more protrusions may extend from a second planar surface of the base portion of each core segment. In another arrangement, each core segment may have one or more recesses with engagement profiles, and the stator support may have a plurality of protrusions with corresponding engagement profiles, wherein each protrusion is received in a recess of a corresponding core segment. One or more recesses may be formed in the second planar surface of each core segment. The second planar surface of each core segment faces the first annular surface of the stator support having a plurality of corresponding protrusions or recesses. Each protrusion and its corresponding recess are designed to allow radial movement of the core segment relative to the stator support during the assembly process, with each protrusion receiving in its corresponding recess, but preventing movement of each core segment in the axial and circumferential directions. This arrangement allows each core segment to be easily inserted into the stator support during stator core assembly and removed from the stator support if necessary (e.g., if it needs to be replaced). The core segments are inserted and removed radially. Once assembled, the core segments are held in place relative to the stator support until such a time when they may need to be released for removal from the stator support.

[0016] Core segments can be assembled to stator supports, and stator coils can then be subsequently mounted to the respective assembled core segments. Alternatively, stator coils can be mounted to the respective core segments before the core segments are assembled to the stator supports. Stator coils can be preformed using any known method, including a "resin-rich" process in which individual stator coils are impregnated with a suitable resin and then mounted to the core segments. Alternatively, stator coils can be mounted to the respective core segments during core segment manufacturing, and the core segments and mounted stator coils can be subjected to a vacuum pressure impregnation (VPI) process using a suitable resin. In other words, core segments can be prefabricated to include integrated stator coils that can be electrically interconnected after the core segments are inserted into the stator supports.

[0017] Each core segment may have a laminated structure. In other words, each core segment may be formed by stacking thin laminated sheets, which are stamped or cut to have an outer contour. The laminated sheets may optionally be made of electrical grade steel with an insulating coating. The laminated sheets are stacked together in the radial direction. The laminated structure significantly reduces eddy current losses in the core segment during motor operation. The stacked laminated sheets are preferably bonded together. The outer contour of the laminated sheets may define the base portion and tooth portion of each core segment. The outer contour of the laminated sheets may also define one or more protrusions or one or more recesses as described above for mounting each core segment to the stator support. In one arrangement, the laminated sheets stacked together may be identical, such that the side surfaces of the base portion of each core segment are initially substantially parallel. The core segment may then be machined to angle the side surfaces, and the base portion has a substantially trapezoidal cross-section when viewed axially. Using identical laminated sheets simplifies the stacking process. If the stator core is not segmented, it may also have a laminated structure. It can also have a solid structure.

[0018] Each stator core retainer is received in a corresponding substantially trapezoidal gap between a pair of adjacently mounted stator coils. Each retainer is preferably removable, or removably mounted, as described in more detail below. This allows for the removal of a particular retainer if necessary. The stator assembly is designed such that the retainers are allowed to move radially relative to the adjacently mounted stator coils (and relative to the stator core / core segment and stator support) at least during the assembly process, i.e., the position of the retainers can be adjusted independently in the radial direction. The retainers can then be fixed in place so that further relative movement is not possible, for example, during normal operation of the motor. Because the facing surfaces of the pair of adjacently mounted stator coils are angled relative to each other (i.e., they are not parallel) to define a substantially trapezoidal gap between them, this means that the contact pressure exerted by the contact surface of each retainer and / or the contact area between the contact surface and the facing surface of the adjacently mounted stator coil can be adjusted depending on the radial position of each retainer within the corresponding gap. In other words, moving the retainer radially inward relative to the fixed portion of the stator assembly will increase the contact pressure applied to the adjacent mounted stator coils, and vice versa. The contact pressure can be adjusted to ensure that each stator coil is properly supported within the stator assembly. The contact pressure will typically have a component in the circumferential direction. Once the contact pressure is adjusted to the desired level (i.e., once the radial positioning of each retainer is adjusted), the retainer can be fixed or locked in place. The contact surfaces of each retainer can be arranged at substantially the same angle as the facing surfaces of the adjacent mounted stator coils, so that each retainer has a substantially trapezoidal cross-section when viewed in the axial direction. If the contact surfaces and facing surfaces have substantially the same angle, they can achieve better sliding surface contact. This can improve heat transfer from the adjacent mounted stator coils to the retainers by increasing the contact surface area between the adjacent mounted stator coils and the retainers, especially when the contact pressure increases to maintain efficient thermal coupling. Alternatively, as explained above, one or more insertion members can be positioned between each contact surface and the facing surface of the adjacent mounted stator coil. In this arrangement, the contact surfaces and / or facing surfaces can enter into sliding surface contact with the insert members(s). For example, one or more insert members can be used to compensate for any differences in the shape of the stator coils. Moving the retainer radially inward relative to the fixed portion of the stator assembly increases the contact area—the surface area of ​​each contact surface that contacts the facing surfaces of an adjacent mounted stator coil or any of the insert members(s), and vice versa.

[0019] Each gap is generally defined on three sides by the facing surface of the adjacent mounted stator coil and the base portion of the adjacent core segment (i.e., the core segment in which the adjacent stator coil is mounted). If the stator core is not segmented, each gap is generally defined on three sides by the facing surface of the adjacent mounted stator coil and the base portion of the stator core. Each gap may be open on the remaining sides, and particularly open at the radially outer portion, which defines an opening into which a corresponding retainer may be inserted radially during assembly. In other words, the retainer may be inserted radially inward from the outer diameter of the stator coil into the gap and then secured in place. Each retainer may include a first surface and a second opposing surface facing the core segment or stator core. The second surface of each retainer may contact the base portion of the adjacent core segment or the base portion of the unsegmented stator core. The interface between adjacent core segments (i.e., where the interface is defined by adjacent side surfaces of the base portion, which may be in direct contact or spaced apart, and may extend substantially along the radius of the stator core) may be substantially disposed at the center of the second surface of the respective retainer. Each retainer may include a pair of angled side surfaces defining a contact surface. Each retainer may include a first end and a second end, the first end being disposed at a radially outer portion of the stator core and the second end being disposed at a radially inner portion of the stator core, or vice versa. The first end and / or the second end may be closed or may be open, as described in more detail below.

[0020] Each retainer's first surface facing away from the stator core may include at least one retaining feature (or lip) extending in the circumferential direction (or protruding from the retainer) and adapted to prevent movement of adjacent stator coils in the axial direction. A pair of retaining features (or lips) may extend in opposite circumferential directions and are adapted to prevent movement of two adjacent stator coils in the axial direction. Each retaining feature may extend substantially the entire edge of the first surface of each retainer. Each retaining feature may directly contact the adjacent edge of the corresponding stator coil. Thus, each stator coil may be axially retained or captured between the base portion of the corresponding core segment or unsegmented stator core and the retaining feature of at least one adjacent retainer. Typically, each stator coil will be retained by the retaining feature of an adjacent first retainer overlapping a first side segment of the stator coil and the retaining feature of an adjacent second retainer overlapping a second side segment of the stator coil. Providing such retaining features on the retainer avoids the need for a shoe cap to retain the stator coil, thereby resulting in a significant reduction in cost and material.

[0021] Each retainer may be secured in place by one or more mechanical fasteners (such as bolts or screws). The mechanical fasteners may be inserted through one or more aligned openings in the stator support and stator core. Each retainer may be secured by two or more mechanical fasteners spaced apart in the radial direction. The openings in the stator core may be defined at the interface between adjacent core segments. In this case, a portion of each opening may be defined by a notch or recess formed in the side surface of each adjacent core segment, wherein the notch or recess is aligned when the core segments are assembled together to form the stator core. The mechanical fasteners may then be inserted into one or more aligned openings in each retainer (i.e., in the second surface of each retainer facing the stator core). Each opening in each retainer may be an internally threaded opening for receiving the externally threaded end of the mechanical fastener. The aligned openings in the stator support and stator core may be elongated (e.g., formed as slots extending in the radial direction) to allow each retainer to move radially relative to the remainder of the stator assembly until the mechanical fasteners are fully tensioned. In other words, when threaded into the retainer, one or more mechanical fasteners can move freely within elongated openings or slots in the stator support and stator core, allowing each retainer to move radially, for example, to adjust the contact pressure applied to adjacent stator coils. Thus, a gap exists between the mechanical fastener and the inner surface of the elongated opening or slot, accommodating the required amount of radial movement of the respective mechanical fastener, and therefore the required amount of radial movement of the stator coil retainers secured by one or more mechanical fasteners. Once each retainer is properly positioned within its respective trapezoidal gap, the one or more mechanical fasteners can be fully tensioned to clamp the retainer against the stator core and prevent any further movement in the radial direction. It will be understood that other methods allowing relative movement of each retainer may also be used. For example, each retainer does not, for instance, have one or more internally threaded openings in its second surface, but its second surface may include profiled recesses that capture one or more retaining blocks. When each retainer is positioned in its respective substantially trapezoidal gap, the recesses may extend radially, and each retaining block may slide freely within the recesses. For example, the recess may have a dovetail or T-shaped profile that captures each retaining block, and each retaining block may have a corresponding dovetail or T-shaped profile. Each retaining block may include an opening for receiving a mechanical fastener (such as a bolt or screw). In particular, the opening in each retaining block may be an internally threaded opening for receiving the externally threaded end of the mechanical fastener. The mechanical fastener may be inserted through aligned openings in the stator support and stator core, and then into the aligned opening in the retaining block. For example, each retainer may be radially movable to adjust the contact pressure applied to adjacent stator coils. In particular, each retainer may be movable relative to (a plurality of) retaining blocks(s) which remain stationary but slide within the recess.Once each retainer is properly positioned within its corresponding trapezoidal gap, one or more mechanical fasteners can be fully tensioned to clamp the retainer against the stator core and prevent any further movement in the radial direction.

[0022] Instead of using one or more mechanical fasteners (e.g., threaded fasteners), the second surface of each retainer (i.e., the surface facing the stator core) may have at least one engagement profile. The stator core may include a plurality of circumferentially spaced corresponding engagement profiles. For example, each retainer may have one or more dovetail or T-shaped profiles, and the stator core may have a plurality of corresponding dovetail or T-shaped profiles. The engagement profiles on the stator core may be staggered with the tooth portions such that each retainer is positioned in a corresponding trapezoidal gap between a pair of circumferentially adjacent tooth portions. If the stator core is segmented, each engagement profile may be defined by a pair of circumferentially adjacent stator core segments. In one arrangement, each retainer may have one or more protrusions with engagement profiles, and the stator core may have a plurality of recesses with corresponding engagement profiles, wherein each recess receives a protrusion of the corresponding retainer. In another arrangement, each retainer may have one or more recesses with engagement profiles, and the stator core may have a plurality of protrusions with corresponding engagement profiles, wherein each protrusion is received in a recess of the corresponding retainer. Each protrusion and its corresponding recess are designed to allow the retainer to move radially relative to the stator core during the assembly process, with each protrusion receiving in its corresponding recess, but preventing movement of each retainer in the axial and circumferential directions. This arrangement allows each retainer to be easily inserted into the stator core during stator core assembly and removed from the stator core if necessary (e.g., if it needs to be replaced). Once assembled and the contact pressure is adjusted to the desired level (i.e., once the radial positioning of each retainer is adjusted), the retainer is secured in place relative to the stator core. For example, each retainer can be secured or fastened by inserting one or more wedges or clamps into the gaps between the respective engagement contours.

[0023] Each retainer may be prevented from moving radially by one or more stops. For example, stops may be positioned to contact the radially inner end of each retainer to prevent radially inward movement, and stops may be positioned to contact the radially outer end of each retainer to prevent radially outward movement. Stops at the radially outer ends of each retainer may engage after the retainer has been inserted radially into the substantially trapezoidal gap between the mounted stator coils. Axial movement may be prevented by one or more mechanical fasteners that may be inserted through aligned openings in the stator support and stator core, and then into one or more openings in each retainer (e.g., in the second surface). In this case, the retainer will typically be unable to move radially due to the stops, so the aligned openings in the stator support and stator core need not be elongated or formed as slots. If necessary, contact pressure and / or contact area may be adjusted by inserting one or more insertion members (e.g., shims) between the contact surface of each retainer and the facing surface of the adjacent mounted stator coil. Shims can be used to compensate for variations in the stator coils. Each gasket may have substantially parallel main surfaces. If the retainer is movable in the radial direction, for example, if different stops are used to adjust the radial positioning of each retainer, the aligned openings in the stator support and stator core may be elongated or formed as slots, or the retaining blocks described above may be used to allow radial movement of the retainer to adjust the applied contact pressure before the stops engage.

[0024] Each retainer may include at least one channel through which cooling air can flow, for example, from an air inlet to an air outlet. Cooling air may be moved through the retainer by, for example, a fan or blower that circulates air through the stator assembly. Each retainer may include two or more air inlets and / or two or more air outlets. A first end and / or a second end of each retainer may be substantially open; for example, the open end may define one or more air inlets through which cooling air enters the retainer, and one or more air outlets through which cooling air exits the retainer. Cooling air may flow into each retainer through a radially inner end and out of each retainer through a radially outer end, or vice versa. It will be understood that many different air-cooling arrangements are possible; for example, cooling air may flow into each retainer through a single air inlet, flow through one or more internal channels, and out of each retainer through one or more air outlets. For example, one or more internal channels may be arranged such that cooling air flows substantially radially, or in a serpentine or zigzag direction. The direction of cooling air flow within one or more internal channels may be determined by one or more internal baffles or surfaces. During motor operation, the heat generated in the stator coils can be transferred to the retainer, and then to the cooling air flowing through the retainer, i.e., the retainer acts as a heat exchanger. Each internal channel can be divided by one or more baffles to increase the surface area used to transfer heat from each retainer to the cooling air.

[0025] Each retainer may include at least one channel through which cooling liquid can flow (e.g., from a cooling liquid inlet to a cooling liquid outlet). Heat generated in the stator coils during motor operation can be transferred to the retainer and then to the cooling liquid flowing through it; that is, the retainer acts as a heat exchanger. Improved cooling can allow for increased power density of the motor. Each retainer may include at least one channel through which cooling liquid can flow and at least one channel through which cooling air can flow, so that the retainer provides dual cooling functionality, i.e., both air cooling and liquid cooling. Each retainer may include two or more cooling liquid inlets and / or two or more cooling liquid outlets. A first end of each retainer may include one or more cooling liquid inlets and / or one or more cooling liquid outlets. A second end of each retainer may include one or more cooling liquid inlets and / or one or more cooling liquid outlets. It will be understood that many different liquid cooling arrangements are possible; for example, cooling liquid may flow into each retainer through one or more cooling liquid inlets, flow through one or more internal channels, and flow out of each retainer through one or more cooling liquid outlets. Multiple coolant inlets and outlets may be located at either the radially inner end or the radially outer end of each retainer, i.e., multiple coolant inlets and outlets are formed at the same end of each retainer. Multiple coolant inlets may be located at the radially inner end of each retainer, and multiple coolant outlets may be located at the radially outer end of each retainer, or vice versa, i.e., multiple coolant inlets and outlets are formed at opposite ends of each retainer. For example, one or more internal channels are arranged such that the coolant flows substantially radially, or in a serpentine or zigzag direction. If the coolant flows between the multiple coolant inlets and outlets arranged at opposite ends of each retainer, this helps to minimize any differences in cooling provided by the contact surfaces. For an arrangement in which multiple coolant inlets and multiple coolant outlets are located at the same end of each retainer, this typically requires coolant to flow in a first radial direction and then in a second, opposite radial direction (e.g., radially inward and then radially outward, or vice versa), and this can result in a difference in cooling provided by the two contact surfaces, i.e., coolant flowing over one contact surface is warmer than coolant flowing over the other contact surface. The multiple coolant inlets and / or multiple coolant outlets may be formed in a second surface of each retainer (i.e., the surface facing the stator core), or in one or both of the end surfaces of each retainer.

[0026] The conduit may be fluidly connected to each coolant inlet, through which coolant is supplied, and may also be fluidly connected to each coolant outlet, through which coolant is removed. The conduit may pass through the stator core and stator support, or optionally only through the stator support.

[0027] Pipes can be fixedly connected to each retainer, for example, by welding, bonding, or fitting them to the retainer body. This, for example, allows for easy detection of coolant leaks by visually inspecting the weld points at the ends of the retainers.

[0028] Each pipeline may include an isolation valve or a check valve.

[0029] The piping can be fluidly connected to form a closed-loop liquid cooling circuit. One or more cooling circuit outlets can be fluidly connected to one or more cooling circuit inlets to allow the coolant to recirculate through the closed-loop liquid cooling circuit. For example, the closed-loop liquid cooling circuit may include one or more heat exchangers for removing heat from the coolant and one or more pumps for circulating the coolant. Any suitable coolant can be used, such as water, propylene glycol, etc.

[0030] For example, each retainer may be formed from stainless steel, aluminum, or a suitable ceramic material. Each retainer may be formed by any suitable manufacturing method, such as, for example, machining or 3D printing.

[0031] Each retainer may be formed of a single type of material, such as a non-magnetic material, such as stainless steel, aluminum, or a suitable ceramic material. In other arrangements, a first portion of each retainer arranged adjacent to the stator core may be made of a magnetic material, and a second portion of each retainer spaced apart from the stator core (and, for example, defining a first surface of each retainer) may be made of a non-magnetic material. In other arrangements, the inner portion (or “core”) of each retainer may be made of a magnetic material, and the outer portion (or “surface portion”) of each retainer may be made of a non-magnetic material.

[0032] Multiple grooves or channels may be formed in the first surface of each retainer facing away from the stator core. The grooves or channels provide an irregular surface, which helps to minimize electrical losses.

[0033] Multiple grooves or channels may be formed in the contact surface or side surface of each retainer. Cooling air can also flow through these grooves or channels, i.e., between the facing surfaces of each retainer and adjacent mounted stator coils or insertion members. Multiple grooves may also optionally be formed in multiple surfaces of the internal channels through which cooling air flows through each retainer; for example, grooves may be formed in one or more inner surfaces of each retainer. One or more fins may also be provided in each internal channel to improve heat transfer to the cooling air.

[0034] Technical Solution 1. A stator assembly (1) of an axial flux motor, the stator assembly (1) comprising: Multiple stator coils (4); A stator core (3) comprising a plurality of toothed portions (2a) arranged circumferentially, each toothed portion (2a) extending axially and adapted to mount a corresponding stator coil (4), wherein adjacent stator coils (4) are spaced apart by substantially trapezoidal gaps (8); and Multiple stator coil retainers (10), each retainer (10) is received in a corresponding gap (8) between a pair of adjacent mounted stator coils (4) and has a position that can be independently adjusted in the radial direction relative to the stator core (3) so that the contact pressure applied by the adjacent retainers (10) to each mounted stator coil (4) can be independently adjusted.

[0035] Technical Solution 2. The stator assembly (1) according to Technical Solution 1, wherein each retainer (10) includes a pair of contact surfaces (10a1, 10a2) spaced apart in the circumferential direction, and wherein each retainer (10) is adapted to apply contact pressure to a corresponding pair of adjacently mounted stator coils (4) through the contact surfaces (10a1, 10a2).

[0036] Technical Solution 3. The stator assembly (1) according to Technical Solution 2, wherein at least a portion of each contact surface (10a1, 10a2) is in direct contact with the facing surface (4c1, 4c2) of a corresponding coil in the pair of adjacently mounted coils (4), or wherein one or more insertion members (54) are positioned between each contact surface (10a1, 10a2) and the facing surface (4c1, 4c2) of a corresponding coil in the pair of adjacently mounted stator coils (4).

[0037] Technical Solution 4. The stator assembly (1) according to Technical Solution 2 or 3, wherein each retainer (10) is adapted to move radially relative to the adjacent mounted stator coil (4) at least during the assembly process to adjust the contact pressure applied by the contact surfaces (10a1, 10a2) of each retainer (10) and / or the contact area between the contact surfaces (10a1, 10a2) and the facing surfaces (4c1, 4c2) of the adjacent mounted stator coil (4).

[0038] Technical solution 5. The stator assembly (1) according to any of the foregoing technical solutions, wherein each tooth portion (2a) includes a pair of substantially parallel side surfaces (2h1, 2h2) that extend substantially radially and are adapted to mount and support the corresponding stator coil (4).

[0039] Technical Solution 6. A stator assembly (1) according to any of the foregoing technical solutions, wherein the stator core (3) is a segmented stator core comprising a plurality of core segments (2) arranged circumferentially, each core segment (2) comprising a tooth portion (2a) extending axially and adapted to mount a corresponding stator coil (4), wherein each core segment (2) further comprises a base portion (2b) having a first planar surface (2c) extending axially from each of the tooth portions (2a) and a second opposing planar surface (2d), and wherein the base portion (2b) further comprises a pair of side surfaces (2e) spaced apart in the circumferential direction and optionally extending substantially along the radius of the stator core (3).

[0040] Technical Solution 7. The stator assembly (1) according to Technical Solution 6, wherein, when viewed in the axial direction, the base portion (2b) of each core segment (2) has a substantially trapezoidal cross section.

[0041] Technical Solution 8. The stator assembly (1) according to Technical Solution 6 or Technical Solution 7 further includes an annular stator support (6), wherein each core segment (2) includes at least one engagement profile (2g), and the annular surface (6a) of the stator support (6) includes a plurality of circumferentially spaced corresponding engagement profiles (6b).

[0042] Technical solution 9. The stator assembly (1) according to any of the foregoing technical solutions, wherein each retainer (10) is removably mounted.

[0043] Technical solution 10. The stator assembly (1) according to any of the foregoing technical solutions, wherein each retainer (10) includes at least one retaining feature (12) that extends in the circumferential direction and is adapted to prevent the adjacent stator coil (4) from moving in the axial direction.

[0044] Technical solution 11. The stator assembly (1) according to any of the foregoing technical solutions, wherein each retainer (10) includes at least one channel (36, 62) for receiving cooling fluid.

[0045] Technical Solution 12. The stator assembly (1) according to Technical Solution 11, wherein each retainer includes one or more cooling air inlets (38), one or more cooling air outlets (40), and one or more internal channels (36) fluidly connected between the one or more cooling air inlets (38) and the one or more cooling air outlets (40).

[0046] Technical Solution 13. The stator assembly (1) according to Technical Solution 11 or Technical Solution 12, wherein each retainer (10) includes one or more coolant inlets (56), one or more coolant outlets (58), and one or more internal channels (62) fluidly connected between the one or more coolant inlets (56) and the one or more coolant outlets (58), and optionally, wherein a conduit (60) fluidly connected to at least one of the coolant inlets (56) and coolant outlets (58) includes an isolation valve or a check valve.

[0047] Technical Solution 14. The stator assembly (1) according to any of the foregoing technical solutions, wherein a portion (66) of each retainer (10) is made of a magnetic material and a portion (68) of each retainer (10) is made of a non-magnetic material, and wherein optionally, a plurality of grooves (70) are formed in the surface of each retainer (10) facing away from the stator core (3).

[0048] Technical solution 15. The stator assembly (1) according to any of the foregoing technical solutions, wherein a plurality of grooves or channels (78) are formed in the contact surfaces (10a1, 10a2) of each retainer (10). Attached Figure Description

[0049] Figure 1 This is a perspective view of a stator assembly according to the present invention; Figure 2 yes Figure 1 A perspective view of the stator support of the stator assembly (i.e., without segmented stator core, stator coils and retainer); Figure 3 yes Figure 1 A perspective view of the stator assembly, including the stator support and segmented stator core (i.e., without stator coils and retainers); Figure 4 yes Figure 3A front perspective view of the core segment of the segmented stator core; Figure 5 yes Figure 3 Top view of the core segment; Figure 6 yes Figure 3 Rear view of the core segment; Figure 7 yes Figure 1 A front view of the stator assembly, including the stator support, segmented stator core, and mounted stator coils (i.e., without retainers); Figure 8 yes Figure 1 A perspective view of the stator assembly, including the stator support, segmented stator core, and mounted stator coils (i.e., without retainers); Figure 9 yes Figure 1 Rear perspective view of the retainer of the stator assembly; Figure 10 yes Figure 9 A frontal perspective view of the first retainer; Figure 11 yes Figure 1 A rear perspective view of a portion of the stator assembly, showing... Figure 9 and Figure 10 The retainer is fixed to the stator support; Figure 12 yes Figure 11 The image shows a front perspective view of a portion of the stator assembly. Figure 13 yes Figure 11 A cross-sectional view of a portion of the stator assembly shown in the image; Figure 14 and Figure 15 This is a rear perspective view of the alternative retainer; Figure 16 This is a cross-sectional view of a portion of the candidate sub-component, showing... Figure 14 and Figure 15 The retainer is fixed to the stator support; Figure 17 This is a front perspective view of the alternative retainer; Figure 18 This is a cross-sectional view of the alternative stator assembly, showing that the retainer is fixed to the stator support using a stop block; Figure 19 This is a front perspective view of the alternative liquid coolant retainer and insert gasket; Figure 20 This is a cross-sectional view of the candidate sub-component, showing... Figure 19 The retainer is fixed to the stator support; Figure 21 yes Figure 19A cross-sectional view of the retainer; Figure 22 This is a cross-sectional view of the alternative stator assembly, showing the alternative liquid-cooled retainer fixed to the stator support; Figure 23 This is a cross-sectional view of the alternative stator assembly, showing the alternative liquid-cooled retainer fixed to the stator support; Figure 24 This is a front perspective view of the alternative dual cooling retainer; Figure 25 This is a cross-sectional view of an alternative liquid-cooled retainer, with the liquid inlet and outlet at opposite ends of the retainer; Figure 26 This is a cross-sectional view of an alternative liquid-cooled retainer, wherein the liquid inlet and outlet are at the same end of the retainer; Figure 27 It is the cross-section of an alternative air-cooled retainer with internal baffles; Figure 28 It is a front perspective view of an alternative retainer with parts made of different materials; Figure 29 It is a front perspective view of an alternative retainer having internal and external parts formed of different materials; and Figure 30 This is a rear perspective view of the alternative retainer, with the groove in the contact surface. Detailed Implementation

[0050] initial reference Figures 1 to 13 The stator assembly 1 of the axial flux motor includes multiple core segments 2 arranged circumferentially to define a segmented stator core 3. It will be readily understood that the stator core may alternatively be a non-segmented stator core having multiple tooth portions arranged circumferentially.

[0051] The stator assembly 1 includes multiple stator coils 4.

[0052] Each core segment 2 includes a toothed portion 2a extending axially and adapted to mount a corresponding stator coil 4, as described in more detail below. Each core segment 2 also includes a base portion 2b. The toothed portion 2a extends axially from the base portion 2b. The base portion 2b of each core segment 2 includes a first planar surface 2c and a second planar surface 2d, from which the toothed portion 2a extends. The first planar surface 2c and the second planar surface 2d are substantially parallel and have a normal extending in the axial direction (i.e., parallel to the longitudinal axis of the stator assembly 1). The base portion 2b of each core segment 2 also includes a pair of side surfaces 2e spaced apart in the circumferential direction and extending substantially along the radius of the stator core 3. The base portion 2b of each core segment 2 also includes a pair of curved end surfaces spaced apart in the radial direction, for example, a first end surface 2f1 disposed at a radially outer portion of the stator core 3 and a second end surface 2f2 disposed at a radially inner portion of the stator core 3. Figure 6 As shown, the base portion 2b of each core segment 2 has a substantially trapezoidal cross-section when viewed along the axial direction, for example, wherein the radially inner end surface 2f2 of each base portion 2b is shorter in the circumferential direction than the radially outer end surface 2f1. Each side surface 2e contacts the facing side surface of the adjacent core segment 2. In other words, the core segment 2 in Figure 3 The images show them assembled together, with the side surfaces 2e of their respective base portions 2b in contact with each other. However, in another arrangement, the core segments 2 can be assembled together, with the side surfaces 2e of their respective base portions 2b spaced apart from each other by gaps or by insert members positioned between adjacent core segments.

[0053] Each core segment 2 is mounted on an annular stator support 6 of the stator assembly. The stator support has a first annular surface 6a and a second opposing annular surface.

[0054] Each core segment 2 has a dovetail engagement protrusion 2g extending from the second planar surface 2d. The first annular surface 6a of the stator support 6 (i.e., the surface facing the core segment) has a plurality of circumferentially spaced dovetail engagement recesses 6b. This is in Figure 2 The clearest example is in Figure 2For clarity, core segment 2, stator coil 4, and retainer 10 are omitted. Each recess 6b receives a protrusion 2g of the corresponding core segment 2. Each protrusion 2g and its corresponding recess 6b are designed to allow radial movement of the core segment 2 relative to the stator support 6 during the assembly process, with each protrusion receiving in its corresponding recess, but designed to prevent movement of each core segment 2 in the axial and circumferential directions. This arrangement allows each core segment 2 to be easily inserted into the stator support 6 during the assembly of the segmented stator core 3, and removed from the stator support if necessary (e.g., if it needs to be replaced). The core segments 2 are inserted and removed radially. Once assembled, the core segments 2 are held in place relative to the stator support 6 until such a time when they may need to be released for removal from the stator support.

[0055] Each core segment 2 may have a laminated structure. In other words, each core segment 2 may be formed by stacking thin laminated sheets, which are stamped or cut to have an outer contour. The laminated sheets may optionally be made of electrical grade steel with an insulating coating. The laminated sheets are stacked together in the radial direction. The laminated structure significantly reduces eddy current losses in the core segments during motor operation. The stacked laminated sheets are preferably bonded together. The outer contour of the laminated sheets may define a toothed portion 2a and a base portion 2b for each core segment 2. The outer contour of the laminated sheets may also define a dovetail projection 2g for mounting each core segment 2 to the stator support 6. In one arrangement, the laminated sheets stacked together may be identical, such that the side surfaces of the base portions of each core segment are initially substantially parallel. The core segment 2 may then be machined so that the side surfaces 2e are angled and the base portion 2b has a substantially trapezoidal cross-section when viewed in the axial direction. Using identical laminated sheets simplifies the stacking process. If the stator core 3 is not segmented, it can also have a laminated structure.

[0056] Each core segment 2 has a toothed portion 2a adapted to mount a corresponding stator coil 4. Specifically, each axially extending toothed portion 2a may include a substantially parallel first side surface 2h1 and a second side surface 2h2 (which extend substantially radially), and a substantially circumferentially extending (i.e., along the circumferential direction of the stator assembly) first end surface 2i1 and a second end surface 2i2. Viewed axially, the toothed portion 2a may have a substantially rectangular cross-section. The side surfaces 2h1 and 2h2 of each toothed portion 2a are used to mount and support the corresponding stator coil 4. Each stator coil 4 includes a substantially radially extending first parallel side segment 4a1 and a second parallel side segment 4a2. Each stator coil 4 also includes a first bent end segment 4b1 and a second bent end segment 4b2 extending between the side segments 4a. The first end segment 4b1 is disposed at a radially outer portion of the stator core 3, and the second end segment 4b2 is disposed at a radially inner portion of the stator core 3. Each stator coil 4 includes an internal gap 4d that receives a toothed portion 2a of a corresponding core segment 2 such that the stator coil 4 extends around the toothed portion 2a when properly mounted. Each stator coil 4 is positioned on a corresponding toothed portion 2a, wherein the inner surfaces of the first side segment 4a1 and the second side segment 4a2 contact or are supported thereon with the facing side surfaces 2h1, 2h2 of the toothed portion 2a.

[0057] like Figure 7 As is most clearly shown, adjacent stator coils 4 are separated by substantially trapezoidal gaps 8.

[0058] The stator assembly 1 includes a plurality of stator coil retainers 10. Each retainer 10 is received in a corresponding gap 8 between a pair of adjacently mounted stator coils 4.

[0059] The position of each retainer 10 can be adjusted independently in the radial direction relative to the stator core 3, as described in more detail below.

[0060] Each retainer 10 includes a first contact surface 10a1 and a second contact surface 10a2 spaced apart in the circumferential direction. Each retainer 10 applies contact pressure to a corresponding pair of adjacently mounted stator coils via the contact surfaces 10a1, 10a2. A first side section 4a1 of each stator coil 4 defines a first facing surface 4c1, and a second side section 4a2 of each stator coil defines a second facing surface 4c2. The first facing surface 4c1 of each stator coil 4 contacts the second contact surface 10a2 of the adjacent first retainer 10, and the second facing surface 4c2 of each stator coil 4 contacts the first contact surface 10a1 of the adjacent second retainer 10. The radial position of the adjacent first retainers 10 is adjustable to change the contact pressure applied to the first side section 4a1 of the stator coil 4—that is, via the contact surface 10a2 and the first facing surface 4c1 of the stator coil. Similarly, the radial position of the adjacent second retainer 10 can be adjusted to change the contact pressure applied to the second side section 4a2 of the stator coil 4—that is, through the first contact surface 10a1 and the second facing surface 4c2 of the stator coil.

[0061] Contact pressure helps hold the stator coils 4 onto the stator core 3 and also improves the cooling of the stator coils. The contact pressure applied to adjacent stator coils 4 can be adjusted or changed by adjusting the position of each retainer 10 in the radial direction. Each retainer 10 is preferably removable, or removably mounted, as described in more detail below. This allows for the removal of a particular retainer 10 if necessary. The stator assembly 1 is designed such that the retainers 10 are allowed to move radially relative to the adjacent mounted stator coils 4 (and relative to the core segment 2 and the stator support) at least during the assembly process, i.e., the position of the retainers 10 can be adjusted independently in the radial direction. The retainers 10 can then be fixed in place so that further relative movement is not possible, for example, during normal operation of the motor. Because the facing surfaces of the paired adjacent stator coils 4 (e.g., the second facing surface 4c2 of the first stator coil 4 and the first facing surface 4c1 of the adjacent second coil 4, separated by the gap 8) are angled relative to each other (i.e., they are not parallel) to define a substantially trapezoidal gap 8 between them, this means that the contact pressure applied by the contact surfaces 10a1, 10a2 of each retainer 10 and / or the contact area between the contact surfaces 10a1, 10a2 and the facing surfaces 4c1, 4c2 of the adjacent stator coils 4 can be adjusted depending on the radial position of each retainer 10 within the corresponding gap 8. In other words, moving the retainer 10 radially inward relative to the fixing part of the stator assembly 1 will increase the contact pressure applied to the adjacent stator coils 4, and vice versa. The contact pressure can be adjusted to ensure that each stator coil 4 is properly supported within the stator assembly 1. The contact pressure will generally have a component in the circumferential direction. Once the contact pressure is adjusted to the desired level (i.e., once the radial positioning of each retainer 10 is adjusted), the retainers 10 can be fixed or locked in place. The contact surfaces 10a1, 10a2 of each retainer 10 can be arranged at substantially the same angle as the facing surfaces 4c1, 4c2 of the adjacently mounted stator coils 4, so that each retainer 4 has a substantially trapezoidal cross-section when viewed in the axial direction. If the contact surfaces 10a1, 10a2 and the facing surfaces 4c1, 4c2 have substantially the same angle, they can achieve better sliding surface contact. This can improve heat transfer from the adjacently mounted stator coils 4 to the retainers 10 by increasing the contact surface area between the adjacently mounted stator coils 4 and the retainers 10, especially when the contact pressure is increased to maintain efficient thermal coupling. Alternatively, as explained below, one or more insertion members can be positioned between each contact surface 10a1, 10a2 and the facing surfaces 4c1, 4c2 of the adjacently mounted stator coils 4. In this arrangement, the contact surfaces 10a1, 10a2 and / or the facing surfaces 4c1, 4c2 can enter into sliding surface contact with the (multiple) inserting members.For example, one or more insertion members can be used to compensate for any differences in the shape of the stator coil 4. Moving the retainer 10 radially inward relative to the fixed portion of the stator assembly 1 increases the contact area—the surface area of ​​each contact surface 10a1, 10a2 that contacts the facing surfaces 4c1, 4c2 of the adjacent mounted stator coil 4 or any(multiple) insertion members, and vice versa.

[0062] Each gap 8 is generally defined on three sides by the facing surfaces 4c1, 4c2 of adjacently mounted stator coils 4 and the base portion 2b of the adjacent core segment 2 (i.e., the core segment on which the adjacent stator coil 4 is mounted). Each gap 8 is open on the remaining sides. Each retainer 10 includes a first surface 10b and a second surface 10c facing the core segment 2. The second surface 10c of each retainer 10 contacts the base portion 2b of the adjacent core segment 2. The interface between adjacent core segments 2 (i.e., where the interface is defined by the adjacent side surfaces 2e of the base portion 2b, which are in direct contact and can extend substantially along the radius of the stator core 3) can be arranged substantially at the center of the second surface 10c of the respective retainer 10. Each retainer 10 includes a pair of angled side surfaces defining contact surfaces 10a1 and 10a2. Each retainer 10 includes a first end portion 10d1 disposed at a radially outer portion of the stator core 3; and a second end portion 10d2 disposed at a radially inner portion of the stator core 3.

[0063] Each retainer 10 has a first surface 10b facing away from the stator core 3, including a retaining feature (or lip) 12 extending in opposite circumferential directions and adapted to prevent axial movement of adjacent stator coils 2. Each retaining feature 12 directly contacts the adjacent edge of the corresponding stator coil 4. Thus, each stator coil 4 can be axially held or captured between the base portion 2b of the corresponding core segment 2 and the retaining feature 12. Typically, each stator coil 4 will be held by the retaining feature 12 of the adjacent first retainer 10 overlapping with the first side segment 4a1 of the stator coil 4 and the retaining feature 12 of the adjacent second retainer 10 overlapping with the second side segment 4a2 of the stator coil 4. Providing such retaining features 12 on the retainers 10 avoids the need for boots to hold the stator coils, thereby resulting in a significant reduction in cost and material.

[0064] Each retainer 10 is secured in place by a pair of radially spaced mechanical fasteners 14 (such as bolts or screws). The mechanical fasteners 14 are inserted through aligned openings 16, 18 in the stator support 6 and the stator core 3. The openings 18 in the stator core 3 are defined at the interface between adjacent core segments 2. Specifically, a portion of each opening is defined by a notch or recess 20 formed in the side surface 2e of each adjacent core segment 2—wherein the notch or recess 20 is aligned when the core segments 2 are assembled together to form the stator core 3. The mechanical fasteners 14 are inserted into a pair of aligned openings 22 in each retainer (i.e., in the second surface 10c of each retainer 10 facing the stator core 3). Each opening 22 is an internally threaded opening for receiving the externally threaded end of the mechanical fastener 14. The aligned openings 16, 18 in the stator support 6 and stator core 3 are elongated (e.g., formed as slots extending radially) to create a gap between the mechanical retainer 14 (including its head portion) and the inner surfaces of the openings 16, 18. If the head portion of each mechanical retainer 14 is larger than the shaft portion, substantially the same gap can be maintained by making the opening of the opening 16 larger. The head portion of each mechanical retainer 14 may include suitably shaped recesses for receiving a drive or other tool for rotating it. Forming the aligned openings 16, 18 as elongated slots means that each retainer 10 is allowed to move radially relative to the rest of the stator assembly 1 until the mechanical retainer 14 is fully tensioned. In other words, when threaded into the retainer 10, the mechanical retainer 14 moves freely within the elongated openings or slots 16, 18 in the stator support 6 and stator core 3 to allow each retainer 10 to move radially, for example, to adjust the contact pressure applied to adjacent stator coils 4. Once each retainer 10 is properly positioned within the corresponding trapezoidal gap 8, the mechanical fastener 14 is fully tensioned to clamp the retainer 10 against the stator core 3 and prevent any further movement in the radial direction.

[0065] Other methods that allow relative movement of each retainer 10 may also be used. For example, refer to Figure 14-16Each retainer 10 does not, for example, have one or more internally threaded openings 22 in its second surface 10c; its second surface may include a T-shaped recess 24 that captures one or more retaining blocks 26. Each retaining block has a corresponding T-shaped profile. The recess 24 extends radially, and each retaining block 26 slides freely within the recess. Each retaining block 26 includes an opening 28 for receiving a mechanical fastener 30, such as a bolt or screw. Specifically, the opening 28 in each retaining block 26 is an internally threaded opening for receiving the externally threaded end of the mechanical fastener 30. The mechanical fastener is inserted through aligned openings 32 and 34 in the stator support 6 and the stator core 3, and then inserted into the aligned opening 28 in the retaining block 26. Each retainer 10 may be radially movable, for example, to adjust the contact pressure applied to adjacent stator coils 4. Specifically, each retainer 10 may be movable relative to the retaining block 26, which remains stationary but slides within the recess 24. Once each retainer 10 is properly positioned within its corresponding trapezoidal gap 8, the mechanical fastener 30 is fully tensioned to clamp the retainer 10 against the stator core 3 and prevent any further movement in the radial direction. Although not shown, the retainer 10 may also be allowed to move radially relative to the stator core 3 if the second surface 10c of each retainer has an engagement profile that engages with a corresponding engagement profile provided on the stator core 3. The engagement profile on each retainer 10 may be, for example, a dovetail or T-shaped profile. The stator core 3 may be provided with a plurality of corresponding dovetail or T-shaped profiles spaced circumferentially, for example, where each profile is located between an adjacent pair of tooth portions. Once the contact pressure is adjusted to the desired level—that is, once the radial position of each retainer 10 is adjusted—the retainer 10 is fixed in place relative to the stator core 3. For example, each retainer 10 may be secured or fastened by inserting one or more wedges or clamps (not shown) into the gaps between the corresponding engagement profiles. This provides an alternative method for adjusting the radial position of each retainer 10 without the need for mechanical fasteners, such as threaded fasteners, like bolts.

[0066] Each retainer 10 may include at least one channel for receiving cooling fluid (e.g., cooling air or cooling liquid) to allow heat from the stator coil 4 to be transferred to the cooling fluid to cool the stator coil 4. Specifically, Figure 9-16The retainer shown includes a pair of cooling channels 36 through which cooling air can flow, for example, from an air inlet 38 to an air outlet 40. The cooling air can be moved through the retainer 10 by, for example, a fan or blower that circulates air through the stator assembly 1. Each retainer 10 has a first end 10d1 and a second end 10d2 that are substantially open; for example, the open ends may define an air inlet 38 and an air outlet 40, through which cooling air enters the retainer 10 via the air inlet 38 and exits the retainer 10 via the air outlet 40. Cooling air flows into each retainer 10 through the second end 10d2 and exits from each retainer 10 through the first end 10d1. However, cooling air can also flow through each retainer 10 in the opposite direction (i.e., radially inward). It will be understood that many different air cooling arrangements are possible; for example, cooling air can flow into each retainer through a single air inlet, flow through one or more internal channels, and exit from each retainer through one or more air outlets. For example, one or more internal channels may be arranged such that cooling air flows substantially radially, or in a serpentine or zigzag pattern. Heat generated in the stator coils 4 during motor operation can be transferred to the retainer 10, and subsequently to the cooling air flowing through the retainer 10, i.e., where the retainer acts as a heat exchanger. Each internal channel may be divided by one or more partitions 42 to increase the surface area for transferring heat from each retainer 10 to the cooling air. For example, in Figure 17 In the middle, each cooling channel 36 is divided by three partitions 42.

[0067] Reference Figure 18Each retainer 10 is prevented from moving in the radial direction by stops 44, 46. For example, stop 46 may be positioned to contact the second end 10d2 of each retainer 10 to prevent radially inward movement, and stop 46 may be positioned to contact the first end 10d1 of each retainer 10 to prevent radially outward movement. The stop 46 at the first end 10d1 of each retainer 10 may engage after the retainer 10 has been inserted radially into the substantially trapezoidal gap 8 between the mounted stator coils 4. Movement in the axial direction may be prevented by mechanical fasteners 48, which may be inserted through aligned openings 50, 52 in the stator support 6 and the stator core 3, and then into an opening in each retainer 10 (e.g., in the second surface 10c). In this case, due to the stops 44, 46, the retainer 10 will typically be unable to move in the radial direction after they are engaged. However, the aligned openings 50, 52 in the stator support 6 and stator core 3 are elongated or formed as slots, as described above. Therefore, the retainer 10 is capable of radial movement before the stops 44, 46 engage. Alternatively, the retaining block 26 described above can be used to allow radial movement of the retainer 10 before the stops 44, 46 engage. Different stops 44, 46 can be used to adjust or accommodate the radial positioning of each retainer 10. If necessary, the contact pressure and / or contact area can also be adjusted by inserting one or more inserting members (e.g., shims) between the contact surfaces 10a1, 10a2 of each retainer 10 and the facing surfaces 4c1, 4c2 of the adjacent mounted stator coil 4. Shims can be used to compensate for variations in the stator coils.

[0068] As described above, each contact surface 10a1, 10a2 can directly contact the facing surfaces 4c1, 4c2 of the adjacently mounted stator coil 4. Therefore, contact pressure can be applied directly to the facing surfaces 4c1, 4c2 of the adjacently mounted stator coil 4 through the contact surfaces 10a1, 10a2 of each retainer 10. However, in some arrangements, such as... Figure 19 and 20 In the arrangements shown, one or more insertion members (e.g., gasket 54) may be positioned between the contact surface and the facing surfaces 4c1, 4c2 of the adjacent mounted stator coil 4, i.e., so that the contact pressure is applied indirectly to the facing surfaces. Figure 19 and 20 Also shown is a retainer 10 cooled by coolant flowing from coolant inlet 56 to coolant outlet 58. A conduit 60 is fluidly connected to coolant inlet 56 and coolant outlet 58. Figure 21As shown, coolant can flow from coolant inlet 56 to coolant outlet 58 through internal channel 62 of retainer 10. Coolant inlet 56 and coolant outlet 58 are disposed in the first end surface 10d1 of retainer 10.

[0069] Figure 22 Alternative retainer 10 is shown, wherein a coolant inlet 56 and a coolant outlet 58 are provided in the second surface 10c of retainer 10. In this case, a conduit 60 extends through openings in the stator support 6 and the stator core 3, as shown. Figure 23 Another alternative retainer 10 is shown, wherein a coolant inlet 56 and a coolant outlet 58 are disposed in the second end surface 10d2 of the retainer 10. In this case, the conduit 60 passes along the radially inner end of the stator core 3 and the stator support 6, as shown.

[0070] Each retainer 10 may include at least one channel through which cooling liquid can flow and at least one channel through which cooling air can flow, so that the retainer 10 provides dual cooling functionality, i.e., both air cooling and liquid cooling. For example, Figure 24 The retainer 10 shown includes a pair of cooling channels 36 through which cooling air can flow, and wherein cooling liquid flows from a cooling liquid inlet 56 to a cooling liquid outlet 58 through an internal channel (not shown) of the retainer 10.

[0071] Figure 25 This illustrates how coolant can flow from coolant inlet 56 to coolant outlet 58 through the internal channel 62 of retainer 10. Coolant inlet 56 is disposed in a first end surface 10d1 of retainer 10, and coolant outlet 58 is disposed in a second end surface 10d2 of retainer, such that coolant flows radially inward through one or more internal baffles 64. However, it will be understood that coolant can flow in the opposite direction, i.e., radially upward.

[0072] Figure 26 This illustrates how the coolant can flow from the coolant inlet 56 to the coolant outlet 58 through the internal channel 62 of the retainer 10. The coolant inlet 56 and the coolant outlet 58 are disposed in the first end surface 10d1 of the retainer 10, and the coolant flows radially inward and then radially outward through the internal baffle 64.

[0073] Although not shown, each pipe 60 may include an isolation valve or a check valve. Pipes 60 may be fluidly connected to form a closed-loop liquid cooling circuit. One or more cooling circuit outlets may be fluidly connected to one or more cooling circuit inlets for the recirculation of the cooling liquid through the closed-loop liquid cooling circuit. For example, the closed-loop liquid cooling circuit may include one or more heat exchangers for removing heat from the cooling liquid and one or more pumps for circulating the cooling liquid. Any suitable cooling liquid may be used, such as water, propylene glycol, etc.

[0074] Figure 27 This illustrates how cooling air can flow through the inner baffle 65. A cooling air inlet 38 is provided in the first end surface 10d1 of the retainer 10, and a cooling air outlet 40 is provided in the second end surface 10d2 of the retainer, such that cooling air flows radially inward through the inner baffle 65. However, it will be understood that cooling air can also flow in the opposite direction, i.e., radially upward.

[0075] Each retainer 10 may be formed of a single type of material, such as a non-magnetic material, such as stainless steel, aluminum, or a suitable ceramic material. (See reference) Figure 28 Each retainer 10 may have a first portion 66 adjacent to the stator core 3 made of a magnetic material, while a second portion 68 of each retainer spaced apart from the stator core 3 (and, for example, defining a first surface 10b of each retainer 10) may be made of a non-magnetic material. A plurality of grooves or channels 70 are formed in the first surface 10b of each retainer 10 facing away from the stator core 3. The grooves or channels 70 provide an irregular surface that helps minimize electrical losses.

[0076] Reference Figure 29 The inner portion 72 (or “core”) of each retainer 10 is made of magnetic material, and the outer portion 74 (or “surface portion”) of each retainer 10 is made of non-magnetic material.

[0077] Reference Figure 30 Multiple grooves or channels 76 are formed in the contact surfaces 10a1, 10a2 of each retainer 10. Therefore, cooling air can also flow through these grooves or channels 76, that is, between each retainer 10 and the facing surfaces 4c1, 4c2 of the adjacent mounted stator coil 4.

Claims

1. A stator assembly (1) of an axial flux motor, the stator assembly (1) comprising: Multiple stator coils (4); The stator core (3) includes a plurality of toothed portions (2a) arranged circumferentially, each toothed portion (2a) extending axially and adapted to mount a corresponding stator coil (4), wherein adjacent mounted stator coils (4) are spaced apart by substantially trapezoidal gaps (8). as well as Multiple stator coil retainers (10), each retainer (10) is received in a corresponding gap (8) between a pair of adjacent mounted stator coils (4) and has a position that can be independently adjusted in the radial direction relative to the stator core (3) so that the contact pressure applied by the adjacent retainers (10) to each mounted stator coil (4) can be independently adjusted.

2. The stator assembly (1) according to claim 1, wherein, Each retainer (10) includes a pair of contact surfaces (10a1, 10a2) spaced apart in the circumferential direction, and each retainer (10) is adapted to apply contact pressure to a corresponding pair of adjacently mounted stator coils (4) through the contact surfaces (10a1, 10a2).

3. The stator assembly (1) according to claim 2, wherein, At least a portion of each contact surface (10a1, 10a2) is in direct contact with the facing surface (4c1, 4c2) of a corresponding coil in the pair of adjacently mounted coils (4), or one or more insertion members (54) are positioned between each contact surface (10a1, 10a2) and the facing surface (4c1, 4c2) of a corresponding coil in the pair of adjacently mounted stator coils (4).

4. The stator assembly (1) according to claim 2 or 3, wherein, Each retainer (10) is adapted to move radially relative to the adjacent mounted stator coil (4) at least during the assembly process to adjust the contact pressure exerted by the contact surfaces (10a1, 10a2) of each retainer (10) and / or the contact area between the contact surfaces (10a1, 10a2) and the facing surfaces (4c1, 4c2) of the adjacent mounted stator coil (4).

5. The stator assembly (1) according to any of the preceding claims, wherein, Each tooth portion (2a) includes a pair of substantially parallel side surfaces (2h1, 2h2) that extend substantially radially and are adapted to mount and support the corresponding stator coil (4).

6. The stator assembly (1) according to any of the preceding claims, wherein, The stator core (3) is a segmented stator core comprising a plurality of core segments (2) arranged circumferentially, each core segment (2) comprising a tooth portion (2a) extending axially and adapted to mount a corresponding stator coil (4), wherein each core segment (2) further comprises a base portion (2b) having a first planar surface (2c) extending axially from each of the tooth portions (2a) and a second opposing planar surface (2d), and wherein the base portion (2b) further comprises a pair of side surfaces (2e) spaced apart in the circumferential direction and optionally extending substantially along the radius of the stator core (3).

7. The stator assembly (1) according to claim 6, wherein, When viewed along the axial direction, the base portion (2b) of each core segment (2) has a substantially trapezoidal cross section.

8. The stator assembly (1) according to claim 6 or claim 7, the stator assembly (1) further comprising an annular stator support (6), wherein each core segment (2) includes at least one engagement profile (2g), and the annular surface (6a) of the stator support (6) includes a plurality of circumferentially spaced corresponding engagement profiles (6b).

9. The stator assembly (1) according to any of the preceding claims, wherein, Each retainer (10) is removably installed.

10. The stator assembly (1) according to any of the preceding claims, wherein, Each retainer (10) includes at least one retaining feature (12) that extends in the circumferential direction and is adapted to prevent the adjacent stator coil (4) from moving in the axial direction.

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