Axial flux motor cooling structure

Abstract

The invention discloses an axial magnetic flux motor cooling structure, which comprises a cooling structure channel and a sealing end cover which are arranged in a stator core, the cooling structure channel and the sealing end cover are matched to form a cooling cavity, and a winding coil is fixed in the cooling cavity. A channel flow guide structure and an end cover flow guide structure are arranged in the cooling cavity, the channel flow guide structure comprises a liquid spraying structure, a wing-shaped flow guide blade, a sub-cavity separation structure and an outlet flow guide structure, and the end cover flow guide structure comprises a gap flow guide baffle, a flow division pressing plate and an outlet backflow structure. Cooling liquid enters the sealed cooling cavity through the flow channel inlet, then forms directional high-speed flow in the cooling cavity, and is discharged from the flow channel outlet after realizing efficient heat exchange with the winding coil. Through immersion type cooling structure integration and diversion system path design, the cooling efficiency and the temperature uniformity of the winding coil are remarkably improved, and meanwhile, the compact structure design is beneficial to improving the motor power density and the system integration degree.

Description

Technical Field

[0001] The present invention relates to the cooling of an axial flux motor, and particularly to a cooling structure for an axial flux motor. Background Art

[0002] With the continuous increase in the demand for high-performance and lightweight drive systems, axial flux motors are developing towards higher torque density and higher current density. This trend has significantly increased the losses in the internal windings of the motor, and the problem of winding temperature rise has become increasingly prominent, becoming one of the key factors restricting its continuous working ability, thermal stability and lifespan. Especially under high-load operating conditions, if the heat of the windings cannot be dissipated in a timely and effective manner, it will lead to insulation aging, an increased risk of demagnetization, and even thermal runaway, seriously affecting the reliability and safety of the system. Therefore, how to effectively improve the winding cooling efficiency in a limited space has become an important technical problem that needs to be solved urgently in the current design of axial flux motors.

[0003] According to the current application and research progress, the winding coils of axial flux permanent magnet motors in the prior art are usually cooled by natural cooling, air cooling or simple water jacket cooling. These cooling structures mainly focus on cooling the periphery of the stator, and the cooling medium cannot effectively reach the winding coil area, resulting in a large thermal resistance and limited heat dissipation efficiency. In addition, some studies have tried to use immersion oil cooling to improve the cooling efficiency, but the sealing design of the current visible implementation schemes has a single function, a complex structure, and is prone to increasing the volume of the motor and affecting the magnetic circuit design and performance stability of the air gap.

[0004] The prior art has made various attempts in the cooling of axial flux permanent magnet motors, but there are still the following key technical bottlenecks that restrict the improvement of the motor power density and system reliability: (1) Low flow efficiency. In the existing immersion cooling structures, there are many blind spots in the flow path of the cooling fluid near the windings, resulting in uneven distribution of the coolant flow velocity and poor local cooling effect. At the same time, the inner wall roughness and narrow flow channels caused by the casting process will further exacerbate the hydraulic loss, and it is necessary to rely on a high-lift cooling pump to maintain the flow rate, resulting in a significant increase in system energy consumption and noise.

[0005] (2) Poor cooling uniformity and prone to local thermal runaway. It is difficult for the prior art to achieve heat load matching. The cooling points are concentrated at the outlet, and the coolant has significantly warmed up when flowing to the target area, and it is impossible to cool the windings at the rear end of the flow direction. In addition, the existing flow channels are basically single-channel, and the cooling of the internal fluid to the heat generation points is relatively inefficient.

[0006] (3) The air gap size is restricted, affecting the magnetic circuit optimization. In some existing solutions, to achieve the sealing of the coolant, a sealing cover plate needs to be introduced into the air gap between the stator and the rotor. This kind of structure occupies the air gap space and limits the compression and precise control of the air gap size. The electromagnetic performance of the axial flux motor is extremely sensitive to the air gap thickness. A slight increase in the air gap will lead to a decrease in the magnetic flux density, a decline in the electromagnetic performance, an increase in the assembly error and the risk of high-speed operation, restricting the realization of the high power density of the axial flux permanent magnet motor.

[0007] (4) System complexity and maintenance cost. Traditional solutions rely on external high-power pump sets and complex pipelines, resulting in pressure loss, leakage risk and occupation of installation space; the closed water cooling system has strict requirements for the cooling medium, and the maintenance cost is greatly increased compared with the open system. Summary of the Invention

[0008] The purpose of the present invention is to provide a cooling structure for an axial flux motor, which can at least solve one of the technical problems in the related art to a certain extent.

[0009] To achieve the above-mentioned invention purpose, the present invention adopts the following technical solutions: A cooling structure for an axial flux motor includes a cooling structure channel and a cooling structure end cover fixed on one axial side of the cooling structure channel. The two are hermetically matched to form a cooling cavity. The cooling structure channel is periodically arranged in the circumferential direction with stator core mounting holes matching the shape of the stator core, and the cooling structure channel is matched with the stator core by means of axial insertion. The winding coil is fixed in the cooling cavity, and its lead wire passes through the side of the cooling structure channel.

[0010] Further, the cooling structure channel has an outer circular wall surface, an inner circular wall surface and a plurality of stator core tooth wall surfaces; sealing grooves and sealing rings are arranged at the inner circle, outer circle and stator core tooth wall surfaces of the mating surface between the cooling structure channel and the cooling structure end cover, and a sealed cooling cavity is formed by tightly fitting with a fixing component. The winding coil is axially sleeved into the cooling structure channel through the stator core tooth wall surface.

[0011] Further, a plurality of flow channel inlets, channel diversion structures and flow channel outlets are respectively arranged periodically in the circumferential direction on the bottom surface of the cooling structure channel. A plurality of end cover diversion structures are arranged periodically in the circumferential direction on the surface of the cooling structure end cover. The cooling liquid flows into the sealed cooling cavity through the flow channel inlet, and under the action of the channel diversion structure and the end cover diversion structure, the flow and heat dissipation performance are enhanced. After directly contacting the winding coil for heat exchange, it flows out of the cooling cavity through the flow channel outlet, realizing the efficient cooling of the winding coil.

[0012] Further, the channel flow guiding structure includes a liquid ejection structure provided at the inlet of each flow channel on the bottom surface of the cooling structure channel. The ejection direction of the liquid ejection structure is radially outward, and the outlet cross-section is a tapered Venturi structure, which improves the initial kinetic energy of the liquid flowing into the flow channel inlet.

[0013] Further, the channel flow guiding structure also includes wing-shaped drainage vanes whose distribution positions correspond one-to-one with the liquid ejection structures, and the axial cross-section thereof is a wing-shaped contour with continuously varying curvature; the leading edge of the wing-shaped drainage vane has a large radius of curvature and is aligned with the axis of the liquid ejection structure to reduce the risk of fluid flow separation; the middle to the tail of the wing-shaped drainage vane gradually flattens and points to the gap between the winding coils, guiding the cooling liquid to flow into the gap between the winding coils in a directional acceleration manner to achieve efficient heat exchange.

[0014] Further, the channel flow guiding structure also includes a sub-cavity separation structure provided at the axis of each winding coil and extending radially to the winding coil, which divides the sealed cooling cavity into multiple independent sub-cavities distributed on both sides of the wing-shaped drainage vane, blocking the non-directional cross-flow between the sub-cavities, and improving the coolant flow rate and heat exchange efficiency by suppressing the circumferential pressure equilibrium.

[0015] Further, a channel is opened inside the sub-cavity separation structure for leading out the lead wires of the winding coils.

[0016] Further, the channel flow guiding structure also includes an outlet drainage structure provided at the outlet of each flow channel on the bottom surface of the cooling structure channel, which is composed of two arc-shaped guiding surfaces symmetrically arranged along the radial axis, intersecting at the inner end and gradually expanding towards the outer end, and the axial cross-section thereof is a continuously varying curvature trumpet-shaped contour; The inner end of the outlet drainage structure is opposite to the central axis of the gap between two adjacent winding coils, and the cooling fluid is guided to the end of the winding coil through the arc-shaped guiding surface to improve the heat exchange efficiency; the bending direction of the arc-shaped guiding surface is the same as that of the end of the adjacent winding coil, and the curvature of the arc-shaped guiding surface is smaller than that of the end of the winding coil; The outer end opening of the outlet drainage structure is trumpet-shaped, surrounding both sides of the flow channel outlet and having a certain gap from the inner side wall of the outer circle of the cooling structure channel, thereby constructing a diffusive Venturi structure; this diffusive Venturi structure can gradually slow down the flow rate when the cooling fluid leaves the sealed cavity, and effectively convert part of the kinetic energy into static pressure, improving the pressure recovery ability at the outlet of the flow channel, which is beneficial to forming a stable flow pressure gradient, thereby reducing local turbulence and flow loss.

[0017] Further, the end cover flow guiding structure includes a plurality of gap drainage baffles, shunt pressing plates and outlet return structures respectively arranged periodically along the circumferential direction on the bottom surface of the cooling structure end cover; The gap drainage baffle extends radially between every two stator mounting hole positions, and its top is pointed to tightly insert between two winding coils, which can limit the flow between two adjacent winding coils within the winding coils and prevent overflow from weakening the cooling effect; The shunt pressing plates are distributed on both sides of the gap drainage baffle, dividing the cooling fluid between the winding coils and the end cover of the cooling structure into multi-channel flows, and simultaneously playing a role in tightly pressing and fixing the winding coils; The outlet reflux structure has a curved wall reflux shape, and is respectively arranged on the radial inner side and the radial outer side of each stator mounting hole position, and forms a reflux in cooperation with the cooling structure channel to achieve enhanced cooling of local hot spots of the winding coils.

[0018] Furthermore, axial flow expansion channels are provided on the outer periphery of the wall surface of the stator core teeth of the cooling structure channel for cooling the inner side of the winding coils to prevent local overheating caused by tight fitting.

[0019] The beneficial effects of the present invention are: (1) Improve the flow channel efficiency and heat exchange capacity In the present invention, the wing-shaped drainage blades optimize the hydrodynamic performance through the design of the wing-shaped cross-section flow channel. The wing-shaped structure can reduce the risk of boundary layer separation and reduce turbulent losses. At the same time, the Venturi effect and Bernoulli effect are used to enhance the local flow velocity to solve the reflux problem. Combining the low-pressure zone ejection technology, a directional negative pressure is formed in the key heat load area to actively guide the coolant to converge towards the high-temperature points.

[0020] (2) The advantages of non-air-gap intrusion type sealing structure and structural lightweight The cooling skeleton structure proposed in the present invention adopts a non-air-gap intrusion type sealing method, arranging the sealing structure outside the air-gap space, avoiding the encroachment of the traditional sealing structure on the air-gap thickness of the motor, ensuring the stability of the air-gap size of the motor and the consistency of the electromagnetic performance. At the same time, the proposed cooling skeleton structure adopts lightweight materials and an integrated structure layout, significantly reducing the weight of the cooling system while improving the cooling efficiency of the stator winding coils, and further improving the power density and system integration degree of the axial-flux permanent magnet motor.

[0021] (3) Structural integration and enhanced reliability The present invention uses additive manufacturing technology (or injection molding technology) to embed the wing flow channel and the ejection cavity into the cooling structure body, eliminating the connection points of the split structure implementation method, reducing the leakage risk; through the topological optimization of the flow channel, the winding coils are embedded to achieve a compact layout, reducing the installation space requirements compared with the traditional scheme, and adapting to the narrow thermal management space of high-power density motors and engines. Description of the Drawings

[0022] Figure 1 It is an exploded view of the main components of the present invention; Figure 2 An isometric view of the combination of the cooling structure channel and the cooling structure end cover in the present invention; Figure 3 A bottom view of the combination of the cooling structure channel and the cooling structure end cover in the present invention; Figure 4 A schematic diagram of the combination of the cooling structure channel and the winding coil in the present invention; Figure 5 For Figure 4 An enlarged view of part A in; Figure 6 A schematic diagram of the cooling structure end cover in the present invention; Figure 7 For Figure 6 An enlarged view of part B in; Figure 8 A design parameter diagram of the inlet diversion structure in the present invention; Figure 9 A schematic diagram of the cooling liquid flow path in the present invention.

[0023] The drawings are only for illustrative purposes and should not be construed as limiting the present invention; for better illustration of this embodiment, some components in the drawings are omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention.

[0025] Embodiment 1: As Figures 1 to 9 shown, this embodiment discloses an axial flux motor cooling structure, including a cooling structure channel 1, a cooling structure end cover 2, a seal ring combination 9, a winding coil 3, and a stator core 5.

[0026] The cooling structure channel 1 is inserted into the stator core tooth part 501 from the axial direction through the stator core mounting holes 101 arranged periodically in the circumferential direction, and is closely fitted with the stator core 5. The bottom mating surface 102 of the cooling structure channel is closely attached to the upper surface 502 of the stator core yoke. The winding coil 3 is sleeved into the cooling structure channel 1 from the axial direction through the core mounting holes 101, and is pressed and fixed in the cooling cavity formed by the cooling structure channel 1 and the cooling structure end cover 2.

[0027] The cooling structure channel 1 and the cooling structure end cover 2 can be processed and formed from insulating materials by additive manufacturing (or injection molding technology), and are tightly fixed axially through a plurality of inner ring fixing screw holes 41 and outer ring fixing screw holes 42. In order to improve the sealing performance of the internal cooling chambers of the two, a corresponding sealing structure is provided at the connection between the cooling structure channel 1 and the cooling structure end cover 2 and is closely matched with the sealing ring assembly 9.

[0028] The cooling structure channel 1 has an outer circular wall surface, an inner circular wall surface, and a plurality of stator core tooth wall surfaces; sealing structures are provided at the inner circle, outer circle, and stator core tooth wall surfaces of the mating surface between the cooling structure channel and the cooling structure end cover.

[0029] The sealing structure specifically includes: an inner wall sealing groove 91 provided in the cooling structure channel 1, and an inner wall sealing rubber ring 911 installed in cooperation with it; an outer wall sealing groove 92, and an outer wall sealing rubber ring 921 installed in cooperation with it; a tooth top sealing groove 93 provided on each stator core tooth wall surface, and a tooth top sealing rubber ring 931 installed in cooperation with it.

[0030] The sealing structure further includes: an end cover inner circle sealing groove 95 (matching with the inner wall sealing rubber ring 911), an end cover outer circle sealing groove 94 (matching with the outer wall sealing rubber ring 921), and an end cover tooth top sealing groove 96 (matching with the tooth top sealing rubber ring 931) provided in the cooling structure end cover 2.

[0031] On the cooling structure channel 1, a cooling circulation flow channel inlet 5 (located at the radially inner position of the bottom surface of the cooling structure channel), a channel diversion structure, and a cooling circulation flow channel outlet 6 (located at the radially outer position of the bottom surface of the cooling structure channel) are arranged periodically along the circumferential direction. The specific structure of the channel diversion structure includes a liquid ejection structure 51, wing-shaped drainage blades 10, a sub-chamber partition structure 11, and an outlet drainage structure 13, all of which are arranged periodically.

[0032] On the cooling structure end cover 2, an end cover diversion structure is arranged periodically along the circumferential direction, which specifically includes an outlet return structure 20, a gap drainage baffle 21, and a diversion pressing plate 22, all of which are arranged periodically.

[0033] The cooling liquid flows in through the cooling circulation flow channel inlet 5, and flows out from the cooling circulation flow channel outlet 6 under the guidance of the end cover diversion structure and the channel diversion structure. During this process, the winding coil 3 is in direct contact with the cooling liquid entering the cooling chamber, realizing full cooling of the winding coil.

[0034] The following introduces the specific details and functions of the channel diversion structure and the end cover diversion structure: The channel diversion structure includes a sub-chamber separation structure 11 provided between each winding coil and the outer wall of the cooling structure channel. While fixing the winding coil 3, the sealed cooling chamber is divided into multiple independent sub-chambers, blocking the non-directional cross-flow between the sub-chambers and improving the coolant flow rate and heat exchange efficiency by suppressing the circumferential pressure balance. In this embodiment, a channel is opened inside the sub-chamber separation structure 11 for connecting the coil winding lead-out wires 31 in parallel or in series to the inner-phase winding end connection 32 (finally led out through the three-phase winding lead-out end 33).

[0035] In each sub-chamber separated by the sub-chamber separation structure 11 and the winding coil 3, a liquid ejection structure 51 is arranged at the inlet of each flow channel on the bottom surface of the cooling structure channel. Its liquid ejection direction is radially outward and the outlet section is a tapered Venturi structure, improving the initial kinetic energy of the liquid flowing into the flow channel inlet.

[0036] The wing-shaped drainage blades 10 are arranged in a circumferential pattern on the radial inner side of the cooling structure channel, corresponding one-to-one with the liquid ejection structures 51, and their axial cross-section is a continuous variable-curvature wing-shaped profile.

[0037] The leading edge (inner end) of the wing-shaped drainage blade has a large radius of curvature and is aligned with the axis of the liquid ejection structure. The tail (outer end) of the wing-shaped drainage blade 10 points to the gap between the two winding coils, guiding the accelerated and directed inflow of the cooling liquid into the winding coil gap. At the same time, a low-pressure area is formed at the impact points near the inner end on both sides of the blade, driving the cooling liquid in the nearby chamber to flow forward.

[0038] Based on Figure 8 the shown design parameters, the design parameters of the liquid ejection structure 51 and the wing-shaped drainage blade 10 in the channel diversion structure are based on the following design method: 1) The relationship between the radius of the flow channel inlet and the radius of the leading edge of the wing-shaped blade can be expressed as:

[0039] where is the distance between the inlet edge and the leading edge of the wing-shaped blade (in this embodiment is taken as 0, and the two are in contact).

[0040] 2) The opening angle of the liquid ejection structure and the chord length of the wing-shaped blade and the radius of the leading edge of the wing-shaped blade can be designed to satisfy the following relationship:

[0041] 3) The radius of the leading edge of the wing-shaped blade and the chord length The relationship can be designed to satisfy the following relational expressions:

[0042] 4) The thickness of the airfoil blade and the chord length satisfy the following:

[0043] wherein, is the thickness ratio of the airfoil blade, and in this example, it takes 0.15.

[0044] 5) According to Bernoulli's equation, the relationship between the inlet pressure and velocity , the pressure and velocity at the middle part of the airfoil blade, and the outlet pressure and velocity satisfy the following:

[0045] wherein, is the density of the fluid (unit: kg / m 3 ).

[0046] After the inlet fluid reaches the middle part of the airfoil blade through the head of the airfoil blade, the fluid velocity increases and the pressure decreases to form a low-pressure area. During this process, gradually increases to , corresponding to decreasing to . During the process of the fluid flowing from the middle part of the airfoil blade to the tail, the curvature of the airfoil surface is small, and the fluid in the surrounding chamber is sucked into the low-pressure area and flows radially towards the outlet. At this time, a high-pressure accumulation area is formed at the outlet, and the fluid is pressed into the gap between the two winding coils. During this process, gradually decreases to , corresponding to increasing to . Thus, the relationship between the thickness of the airfoil blade and the outlet pressure and velocity is expressed as

[0047]

[0048] Based on the relationships between the parameters described by the above formulas, the structural detail dimensions can be optimized to obtain a design scheme with good flow guiding performance. In practical applications, further optimization and adjustment can be carried out according to specific application scenarios and requirements.

[0049] The liquid ejection structure 51 and the wing-shaped drainage vane 10 in the above channel diversion structure are mainly responsible for improving the cooling effect of the winding coil gap.

[0050] The channel diversion structure forms a high-speed - low-pressure synergistic effect through the coordinated cooperation of the liquid ejection structure, the wing-shaped drainage vane, and the sub-cavity separation structure. The cooling liquid flowing in from the runner inlet is accelerated by the liquid ejection structure and forms a low-pressure area at the leading edge of the wing-shaped drainage vane. It is guided and accelerated by the airfoil-shaped drainage vane and injected into the winding gap. At the same time, the cooling liquid in the cavities on both sides of the wing-shaped drainage vane is strengthened for secondary flow along the drainage direction, enhancing the directivity of the cooling liquid flow and the heat transfer efficiency.

[0051] The channel diversion structure also includes an outlet drainage structure 13 arranged in a circumferential pattern on the radial outer side of the cooling structure channel. It consists of two arc-shaped diversion surfaces that are symmetrically arranged along the radial axis, intersect at the inner ends, and gradually expand towards the outer ends, forming a continuous variable-curvature trumpet-shaped profile with a small inner end and a large outer end in the axial section. The outer end of the outlet drainage structure 13 corresponds to the cooling circulation runner outlet 6 one by one, and the inner end of the outlet drainage structure is located between the two winding coils 3. The bending direction of the arc-shaped diversion surface is the same as that of the adjacent winding coil ends, and the curvature of the arc-shaped diversion surface is smaller than that of the winding coil ends. The cooling fluid passing through the winding coil gap flows along the arc-shaped diversion surface to both sides, cooling the radial outer end area of the winding coil.

[0052] The trumpet-shaped opening at the outer end of the outlet drainage structure 13 clamps the cooling circulation runner outlet 6 and has a certain gap from the inner side wall of the outer circle of the cooling structure channel, thereby constructing a diffuser-type Venturi structure. This diffuser-type Venturi structure can gradually slow down the flow velocity when the cooling fluid leaves the sealed cavity, and effectively convert part of the kinetic energy into static pressure, improving the pressure recovery ability at the runner outlet, which is conducive to forming a stable flow pressure gradient, thereby reducing local turbulence and flow losses.

[0053] In order to further enhance the cooling effect of the top and radial outer ends of the winding coil, the end cover diversion structure provided on the cooling structure end cover 2 has the following characteristics: The gap drainage baffle 21 included in the end cover diversion structure extends radially, and its top is pointed to tightly insert between the two winding coils. It can limit the flow between the two adjacent winding coil gaps within the winding coils, preventing overflow and weakening of the cooling effect.

[0054] The flow diversion pressing plates 22 are respectively located on both sides of the gap drainage baffle 21. The flow diversion pressing plates 22 can not only press the corresponding winding coils 3, but also standardize the flow pattern of the cooling fluid between the winding coils 3 and the cooling structure end cover 2, dividing it into multi-channel flow to reduce liquid flow losses and enhance the heat transfer ability.

[0055] The outlet reflux structures 20 are respectively located on the radial outer sides of the winding coils. Both sides thereof are in the shape of curved-wall reflux (with relatively small hydraulic losses), and are used to form reflux to cool the radial outer end regions of the winding coils.

[0056] The working principle of the present invention is as follows: By innovating the integrated method of the immersion cooling structure and optimizing the design of the diversion system path, the cooling efficiency and temperature uniformity of the winding coils are significantly improved.

[0057] The cooling structure seals the winding coils inside the cooling cavity, and improves the cooling efficiency of the winding coils through the efficient circulation of the cooling liquid; at the same time, the non-air-gap intrusion design of the cooling structure and the integrated installation method based on hole plugging ensure that the rotor magnetic circuit design of the axial flux motor is not affected.

[0058] The optimized design of the diversion system path optimizes the flow path of the cooling liquid into three parts: gap flow, end flow, and top flow, and at the same time realizes targeted and efficient heat dissipation for the high-temperature regions of the gaps, ends, and tops of the winding coils.

[0059] The top flow near the end cover of the cooling structure is to strengthen the heat exchange between the upper-layer winding coils and the cooling liquid. As Figure 9 shown in (a) therein, the flow direction of the cooling liquid is indicated by a dotted-line arrow. The cooling medium enters the inside of this structure through the cooling circulation channel inlet 5, is accelerated by the liquid ejection structure 51, enters the top region of the winding coil 3, and is divided into 4 flow channels in this region via the gap drainage baffle 21 and the shunt pressing plate 22, making the overall flow loss smaller.

[0060] When the cooling medium flows to near the cooling outlet, the outlet reflux structure 20 has a curved-wall reflux shape with relatively small hydraulic losses, and cools the radial outer end of the winding coil through reflux.

[0061] The flow path of the winding coil gap is as Figure 9 shown by the dash-line arrow in (b) therein. After the cooling medium is accelerated by the cooling circulation channel inlet 5 and the liquid ejection structure 51, a low-pressure area is formed at the front impact points on both sides of the wing-shaped drainage blade 10, thereby driving the secondary flow of the cooling liquid in the two adjacent cavities, entering the gap region between two adjacent winding coils 3, then flowing through the outlet drainage structure 13 to strengthen the cooling of the winding coil ends, and finally flowing out through the cooling circulation channel outlet 6.

[0062] Figure 9 (c) therein schematically shows the overall path of the diversion system. The dotted-line arrow represents the top flow near the end cover of the cooling structure, the dash-line arrow represents the flow in the winding coil gap and the end flow, and the solid-line arrow represents the inflow and outflow of the cooling liquid through the flow channel inlet 5 and the flow channel outlet 6.

[0063] Embodiment 2: As Figure 5 shown, based on the first embodiment, an axial flow expansion channel 12 is provided on the outer periphery of the wall surface of the stator core teeth in the cooling structure channel in this embodiment, so that the inner side of the winding coil 3 has a stronger axial flow heat dissipation capacity, which is used to cool the inner side of the winding coil to prevent local overheating caused by close fitting.

[0064] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be modified or equivalently replaced, and any modification or partial replacement without departing from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

[0065] If terms such as "first" and "second" are used in this article to limit components, those skilled in the art should be aware that the use of "first" and "second" is only for the convenience of describing the present invention and simplifying the description. Without additional declaration, the above terms have no special meaning.

[0066] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0067] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Claims

1. An axial flux motor cooling structure, characterized in that: It includes a cooling structure channel and a cooling structure end cover fixed on one axial side of the cooling structure channel. They are sealed and fitted together to form a cooling cavity. The stator core mounting hole positions matching the shape of the stator core are arranged periodically along the circumferential direction of the cooling structure channel. The cooling structure channel is fitted with the stator core by means of axial insertion. The winding coil is fixed in the cooling cavity, and its lead wire passes through the side surface of the cooling structure channel.

2. The axial flux motor cooling structure according to claim 1, characterized in that: The cooling structure channel has an outer circular wall surface, an inner circular wall surface and multiple stator core tooth wall surfaces. Sealing grooves and sealing rings are provided at the inner circle, outer circle and stator core tooth wall surfaces of the mating surface between the cooling structure channel and the cooling structure end cover, and a sealed cooling cavity is formed by tight fitting through a fixing component. The winding coil is axially sleeved into the cooling structure channel through the stator core tooth wall surface.

3. The axial flux motor cooling structure according to claim 2, wherein: Multiple flow channel inlets, channel diversion structures and flow channel outlets are respectively arranged periodically along the circumferential direction of the bottom surface of the cooling structure channel. Multiple end cover diversion structures are arranged periodically along the circumferential direction of the surface of the cooling structure end cover. The cooling liquid flows into the sealed cooling cavity through the flow channel inlet. Under the action of the channel diversion structure and the end cover diversion structure, it directly contacts the winding coil to realize heat exchange and then flows out of the cooling cavity through the flow channel outlet.

4. The axial flux motor cooling structure according to claim 3, characterized in that: The channel diversion structure includes a liquid ejection structure arranged at each flow channel inlet on the bottom surface of the cooling structure channel. The ejection direction of the liquid ejection structure is radially outward, and the outlet cross-section is a tapered Venturi structure.

5. The axial flux motor cooling structure according to claim 4, wherein: The channel diversion structure also includes wing-shaped drainage vanes whose distribution positions correspond one-to-one with the liquid ejection structures. The axial cross-section of the wing-shaped drainage vanes presents a continuously variable curvature wing-shaped profile. The leading edge curvature radius of the wing-shaped drainage vanes is large and is aligned with the axis of the liquid ejection structure. The middle to the tail of the wing-shaped drainage vanes gradually flattens and points to the winding coil gap, guiding the cooling liquid to flow into the winding coil gap in a directional and accelerated manner.

6. The axial flux motor cooling structure according to claim 5, wherein: The channel diversion structure also includes a sub-cavity separation structure arranged at the axis of each winding coil and extending radially to the winding coil, which divides the sealed cooling cavity into multiple independent sub-cavities distributed on both sides of the wing-shaped drainage vanes, blocking the non-directional cross-flow between the sub-cavities.

7. The axial flux motor cooling structure according to claim 6, characterized in that: A groove is opened inside the sub-cavity separation structure for leading out the lead wire of the winding coil.

8. The axial flux motor cooling structure according to claim 6, wherein: The channel diversion structure also includes an outlet drainage structure arranged at each flow channel outlet on the bottom surface of the cooling structure channel, which is composed of two arc-shaped diversion surfaces symmetrically arranged along the radial axis, intersecting at the inner ends and gradually expanding towards the outer ends. The axial cross-section presents a continuously variable curvature trumpet-shaped profile. The inner end of the outlet drainage structure is opposite to the central axis of the gap between two adjacent winding coils. The cooling fluid is guided to the end of the winding coil through the arc-shaped diversion surface to improve the heat exchange efficiency. The bending direction of the arc-shaped diversion surface is the same as the bending direction of the end of the adjacent winding coil, and the curvature of the arc-shaped diversion surface is smaller than the curvature of the end of the winding coil. The outer end opening of the outlet drainage structure is trumpet-shaped, surrounding both sides of the flow channel outlet and having a certain gap from the inner side wall surface of the outer circle of the cooling structure channel, thereby constructing a diffusive Venturi structure. This diffusive Venturi structure can gradually slow down the flow velocity when the cooling fluid leaves the sealed cavity and effectively convert part of the kinetic energy into static pressure.

9. The axial flux motor cooling structure according to any one of claims 3-8, characterized in that: The end cover flow guiding structure includes a plurality of gap drainage baffles, shunt pressing plates, and outlet reflux structures that are periodically arranged circumferentially on the bottom surface of the cooling structure end cover; The gap drainage baffles are distributed radially between every two stator mounting hole positions, and their tops are pointed to tightly insert between two winding coils, which can limit the flow between the gaps of two adjacent winding coils to between the winding coils and prevent overflow; The shunt pressing plates are distributed on both sides of the gap drainage baffles, dividing the cooling fluid between the winding coils and the cooling structure end cover into multi-channel flows, and at the same time playing a role in pressing and fixing the winding coils; The outlet reflux structure has a curved wall reflux shape and is respectively arranged on the inner and outer sides of the radial direction of each stator mounting hole position, and cooperates with the cooling structure channel to form a reflux to achieve enhanced cooling of local hot spots of the winding coils.

10. The axial flux motor cooling structure according to claim 2, characterized in that: Axial flow expansion channels are provided on the outer circumference of the wall surface of the stator core teeth of the cooling structure channel.

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