Hollow conductor flat wire motor and manufacturing method

Abstract

This invention relates to a hollow conductor flat wire motor, comprising: a stator core and a stator winding. The stator core has several stator slots spaced circumferentially around the stator core. The stator winding is embedded in the stator slots, and the inner wall of the stator slots is covered with insulating paper. The stator winding is a W-pin winding formed by bending and winding hollow conductors into a wavy shape. The hollow conductors are connected to the external cooling oil circuit of the motor to form a liquid circulation channel. The corresponding coolant is driven by an external pump to flow in the liquid circulation channel and remove the heat generated by the W-pin winding. The W-pin winding made of hollow conductors has low resilience, and the damage to the insulating paper and copper wire during winding is much lower than that of W-pin windings made of solid conductors. In addition, the W-pin winding eliminates the need for extensive welding in the motor, solving the problems of numerous welding points, difficult sealing, and oil channel blockage associated with hollow conductors compared to other winding forms.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a hollow conductor flat wire motor and its manufacturing method. Background Technology

[0002] Flat wire winding motors have become one of the mainstream winding forms for electric vehicle drive motors due to their advantages such as high slot fill factor, good thermal conductivity, and high power density. As electric vehicle drive systems develop towards higher frequency and higher voltage, motor loss density continues to rise, placing higher demands on winding heat dissipation. Among various flat wire winding schemes, continuous wave windings have attracted widespread attention due to their advantages such as short end dimensions, high torque density, and suitability for multi-slot, multi-layer motor designs. W-pin windings utilize a single flat wire continuously bent into a wave-like structure and then pressed into the stator slots as a whole, significantly reducing welding workload.

[0003] To further improve the heat dissipation capacity of the winding, in recent years, a technical solution has emerged that involves setting up hollow flow channels inside the flat conductor and introducing cooling medium for direct cooling. However, the existing technology lacks sufficient understanding of the temperature distribution characteristics of the hollow conductor in the wave winding structure and has not yet realized that the W-pin winding has extremely complex multidimensional temperature distribution non-uniformity under actual operating conditions.

[0004] First, regarding the winding path direction, the same conductor in the W-pin winding continuously shuttles between different stator slots, and its temperature fluctuates dramatically along the path: the conductor in the slot section is wrapped by the iron core, and the heat must pass through multiple thermal resistances such as the insulation layer, the medium in the slot, the iron core, and the housing before it can be dissipated. The heat dissipation path is long and the thermal resistance is large, resulting in a large accumulation of heat and the formation of temperature peaks; while the end section is exposed to the internal cooling medium of the motor and usually receives oil spraying or oil immersion cooling, and the heat can be directly dissipated through convection, forming temperature troughs.

[0005] Secondly, in the radial depth direction of the stator slot, there is a clear stratification of temperature between different layers of flat wire: the bottom of the slot is close to the core yoke, with a large heat capacity and a short heat dissipation path, resulting in a relatively low temperature; the slot opening is close to the air gap, with the thickest insulating medium and the closest to the rotor heat source, making heat dissipation the most difficult and resulting in the highest temperature.

[0006] No differentiated structural design has been proposed for this layered temperature field in the existing technology.

[0007] In addition, there is also a cumulative temperature rise in the coolant along the flow direction inside the hollow conductor: the coolant continuously absorbs heat as it flows from the inlet to the outlet. The oil temperature is lowest and the cooling capacity is strongest at the inlet end, while the oil temperature rises and the cooling capacity decreases at the outlet end, resulting in an upward trend in the conductor temperature along the flow direction.

[0008] Therefore, there is an urgent need for a technical solution that can spatially differentiate the conductor structure based on the actual temperature distribution characteristics of the W-pin hollow conductor wave winding, so as to effectively eliminate local hot spots and improve the overall heat dissipation uniformity and reliability of the winding. Summary of the Invention

[0009] In view of the problems existing in the prior art, the present invention provides a hollow conductor flat wire motor and a manufacturing method thereof, which can effectively solve at least one of the problems existing in the prior art.

[0010] In a first aspect of the invention, a hollow conductor flat wire motor is provided, comprising: a stator core and a stator winding. The stator core has a plurality of stator slots spaced circumferentially around the stator core. The stator winding is embedded in the stator slots. The stator winding is a W-pin winding formed by bending and winding a hollow conductor into a wave shape. The hollow conductor is connected to the external cooling oil circuit of the motor to form a liquid circulation channel. The corresponding coolant is driven by an external pump to flow in the liquid circulation channel and carry away the heat generated by the W-pin winding.

[0011] By employing the aforementioned technical means, cooling oil can flow directly through the interior of the conductor, achieving direct cooling of the winding interior. Compared to the traditional method of indirect cooling only through stator slots or the housing, this solution significantly shortens the heat conduction path, substantially improves the motor's heat dissipation efficiency and power density, allows the motor to operate at higher current densities, and effectively suppresses winding temperature rise, extending insulation life.

[0012] Preferably, the W-pin winding is provided with a volume adjustment mechanism. The W-pin winding is provided with a composite end connector. The composite end connector has a cooling oil channel and a gas channel that are isolated from each other. The cooling oil channel is connected to the inner cavity of the hollow conductor. The gas channel is used to supply gas to the volume adjustment mechanism in the inner cavity of the hollow conductor. The gas channel is led out to the outside of the motor through a seal and through the motor end cover. The volume adjustment mechanism includes: a diaphragm arranged in the inner cavity of the stator winding. The diaphragm is provided with multiple air bladders on at least one side. The air bladders on the same side are interconnected and connected to an external gas source. The air bladders on different sides are not interconnected. Gas is introduced through the gas channel of the composite end connector. When the temperature on one side of the diaphragm rises abnormally, the external gas source inflates the air bladders on the side away from the abnormally high temperature of the diaphragm to reduce the inner cavity volume of the stator winding on the side away from the abnormally high temperature. This increases the total amount of cooling oil that can be accommodated in the inner cavity of the stator winding facing the abnormally high temperature, thereby improving the cooling efficiency on the abnormally high temperature side.

[0013] When the temperature in a certain area rises abnormally, by reducing the cross-section of the opposite channel, more cooling oil is forced to flow to the high-temperature area, achieving precise thermal management. This avoids the drawback of insufficient heat dissipation at local hot spots in traditional uniform cooling, effectively eliminating local temperature differences and improving the overall temperature uniformity and reliability of the winding. At the same time, the composite end joint physically isolates the high-pressure oil circuit from the low-pressure air circuit, ensuring that the pneumatic control and oil cooling system do not interfere with each other.

[0014] Preferably, it also includes a control system, comprising: a temperature sensor and a host computer, wherein the temperature sensor is configured to acquire temperature data of the diaphragm deployment area and transmit the temperature data to the host computer, thereby the host computer adjusting the inflation volume of the external air source in response to the temperature data.

[0015] Preferably, the W-pin winding includes: an in-slot section located in the stator slot and a top section and a bottom section located at the top and bottom of the stator slot, respectively, wherein the in-slot section and the top section are respectively provided with a diaphragm and an air bag.

[0016] Preferably, the diaphragm is arranged along the length of the slot section, and the airbag is set on the side of the diaphragm facing the bottom of the slot. When the temperature sensor detects that the temperature on the side of the diaphragm facing the stator slot opening is abnormally high, the host computer controls an external air source to inflate the airbag to expand it, thereby reducing the internal cavity volume of the stator winding near the bottom of the stator slot. This increases the total amount of cooling oil that can be accommodated in the internal cavity of the stator winding near the stator slot opening, thereby improving the cooling efficiency of the side near the stator slot opening.

[0017] Preferably, the diaphragm is positioned at the junction of the top section and the inner section of the trough.

[0018] Preferably, the diaphragm is positioned perpendicular to the horizontal plane at the junction of the top section and the slot section, and the airbag is positioned on the side of the diaphragm facing the outer wall of the stator winding.

[0019] Preferably, the diaphragm is centrally positioned, dividing the inner cavity into two sub-channels; the cooling oil in the sub-channels flows in a laminar flow state; after the airbag inflates, the flow rate of the sub-channel on the side with abnormally high temperature increases is [percentage missing]. satisfy: ,in This is the initial height of the sub-channel. This refers to the airbag inflation volume.

[0020] A second aspect of this application discloses a method for manufacturing a hollow conductor flat wire motor to achieve the above-mentioned technical solution, comprising the following steps: S1. Making the stator core; S2. Hollow conductors are selected to make the W-pin winding; S3. Fabricate a diaphragm and airbag assembly with an edge coated with a heat-capacity adhesive layer. The airbag assembly is initially in a deflation folded flat state. S4. Insert the folded diaphragm and airbag assembly into the hollow conductor through the guide wire from one end of the opening, and pull it along the inner cavity of the conductor to the predetermined cavity section; the guide wire is pre-arranged along the inner cavity of the W-pin winding, and the diaphragm is a flexible tubular structure that can slide into place along the inner cavity of the bending. S5. Heating the predetermined cavity section of the hollow conductor equipped with the diaphragm and airbag assembly, so that the heat-capacitance adhesive layer coated on the edge of the diaphragm and airbag assembly is activated by heat and bonded to the inner wall of the hollow conductor. S6. After the W-pin winding cools down to room temperature, insert insulating paper into the stator slot and then radially embed the W-pin winding into the stator core slot; lead the gas pipeline of the airbag along the diaphragm embedded channel to the end of the W-pin winding and seal it with the gas channel of the composite end joint. S7. Cut off the excess W-pin winding ends, tighten the ends, weld the cooling oil channel of the composite end connector to the motor cooling oil channel, and lead the gas channel out through the seal through the motor end cover and connect it to the external gas source main pipe.

[0021] Therefore, the present invention provides the following effects and / or advantages: (1) The stator adopts hollow conductor W-pin stator winding, and the two ends of the winding are connected to the cooling oil circuit; the inner cavity of the winding is arranged with a diaphragm, and the diaphragm is equipped with an air bag that can be charged and discharged by an external air source. The effective space of the internal oil passage of the hollow conductor is changed by the expansion and contraction of the air bag to realize the distribution of cooling oil flow. (2) The W-pin winding is divided into the slot section, the top section and the bottom section. Diaphragm airbags can be arranged in the slot section and the top section. The airbags in the slot section face the bottom of the stator slot and can actively change the oil distribution on both sides of the winding radially. The diaphragm is mainly arranged at the connection corner between the straight section and the end of the winding to optimize the oil flow in the bending area. (3) Real-time acquisition of local winding temperature, dynamic control of air intake based on temperature, automatic adjustment of airbag expansion degree to match heat dissipation requirements.

[0022] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0023] It should be understood that the above summary and the following detailed description of the invention are exemplary and explanatory, and are intended to provide further explanation of the invention as claimed. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a hollow conductor flat wire motor according to an embodiment of this application; Figure 2This is a schematic diagram of the stator winding structure of a hollow conductor flat wire motor according to an embodiment of this application; Figure 3 This is a cross-sectional schematic diagram of the slotted section of a hollow conductor flat wire motor according to an embodiment of this application; Figure 4 This is a schematic cross-sectional view of the top section of a hollow conductor flat wire motor according to an embodiment of this application; Figure 5 This is a schematic diagram of the volume adjustment mechanism of a hollow conductor flat wire motor according to an embodiment of this application; Figure 6 This is a cross-sectional comparison diagram of the cooling oil flow rate inside the hollow conductor according to an embodiment of this application; Figure 7 A comparative diagram showing the distribution of cooling oil flow rate inside a hollow conductor according to an embodiment of this application; Figure 8 This is a temperature distribution diagram of different regions of the stator winding according to an embodiment of this application; Figure 9 This is a schematic flowchart of a method for manufacturing a hollow conductor flat wire motor according to an embodiment of this application.

[0025] The meaning of each number in the diagram: 1. Stator core; 2. Stator winding; 3. Insulating paper; 201. Top section; 202. Slot section; 203. Bottom section; 4. Diaphragm; 5. Airbag; 6. External air source; 401. Adhesive base. Detailed Implementation

[0026] To facilitate understanding by those skilled in the art, the structure of the present invention will now be described in further detail with reference to the accompanying drawings: like Figures 1 to 5 As shown, a hollow conductor flat wire motor includes: a stator core 1 and a stator winding 2. The stator core 1 has a plurality of stator slots arranged circumferentially around the stator core 1. The stator winding 2 is embedded in the stator slots. The stator winding 2 is a W-pin winding formed by bending and winding hollow conductors into a wave shape. The hollow conductors are connected to the external cooling oil circuit of the motor to form a liquid circulation channel. The corresponding coolant is driven by an external pump to flow in the liquid circulation channel and carry away the heat generated by the W-pin winding.

[0027] The W-pin winding is equipped with a volume adjustment mechanism. The W-pin winding has a composite end connector with mutually isolated cooling oil channels and gas channels. The cooling oil channels are connected to the inner cavity of the hollow conductor. The gas channels are used to supply gas to the volume adjustment mechanism in the inner cavity of the hollow conductor. The gas channels are led out to the outside of the motor through a seal and the motor end cover. The volume adjustment mechanism includes: a diaphragm 4 arranged in the inner cavity of the stator winding 2. The diaphragm 4 has multiple air bladders 5 on at least one side. The air bladders 5 on the same side are interconnected and connected to an external gas source 6. The air bladders 5 on different sides are not interconnected. Gas is introduced through the gas channel of the composite end connector. When the temperature on one side of the diaphragm 4 rises abnormally, the external gas source 6 inflates the air bladders 5 on the side away from the abnormally high temperature of the diaphragm 4 to reduce the inner cavity volume of the stator winding 2 on the side away from the abnormally high temperature. This increases the total amount of cooling oil that can be accommodated in the inner cavity of the stator winding 2 on the side of the abnormally high temperature, thereby improving the cooling efficiency on the side of the abnormally high temperature. In an optional embodiment, the diaphragm 4 is centrally positioned to divide the inner cavity into two sub-channels; after the airbag 5 is inflated, the flow rate of the sub-channel on the side with abnormally high temperature increases is [percentage missing]. satisfy: ,in This is the initial height of the sub-channel. This refers to the airbag expansion amount; the typical range of the hollow conductor inner cavity size in the EV motor field is 1-2 mm. Therefore, the hollow conductor inner cavity size can be selected according to the above range, thereby making the expansion amount of the airbag set on the inner diaphragm of the hollow conductor range from 0.1-0.5 mm; when the airbag is inflated, the proportion of cooling oil flow on the side with abnormal temperature rise is adjusted from the initial 50% to 89% (corresponding to a hollow conductor inner cavity height of 2 mm, therefore the initial height of the sub-channel is...). The airbag inflation volume is 1mm. (0.5mm).

[0028] It also includes a control system, which includes a temperature sensor and a host computer. The temperature sensor is configured to acquire temperature data of the area where the diaphragm 4 is laid and transmit the temperature data to the host computer, so that the host computer adjusts the inflation volume of the external air source 6 in response to the temperature data.

[0029] During operation, the temperature sensor continuously monitors the area equipped with the volume adjustment mechanism. When the temperature of a target area exceeds the threshold, the host computer responds to the abnormal temperature data and controls the external air source 6 to inflate the airbag 5 on the opposite side of the abnormal temperature area. The expansion of the opposite airbag 5 reduces the cross-sectional area of ​​the inner cavity on the opposite side of the area. Since the external cooling oil supply is constant, the amount of cooling oil flowing through the abnormal area in the same time will be greater than the initial state, thereby improving the cooling effect on the abnormal area. When the temperature of the abnormal area returns to within the threshold, the host computer synchronously controls the external air source 6 to exhaust the air and restore the initial cooling oil flow distribution.

[0030] Under motor operating conditions, the temperature distribution of the W-pin winding is extremely uneven, as can be seen from the radial and axial distribution: (1) Radial: Stator slot bottom side: In this area, the W-pin winding is surrounded by multiple layers of silicon steel sheets, resulting in high heat transfer efficiency; Stator slot middle section: There are iron cores on both sides, and heat accumulation is relatively serious; Stator slot opening side: close to the air gap, it can obtain auxiliary heat dissipation through the air gap, but the heat transfer efficiency is lower compared to the silicon steel sheet at the bottom of the slot.

[0031] (2) Axial direction: Cooling oil inlet end: The cooling oil temperature is the lowest, and the heat exchange efficiency is high; In the middle section of the stator slot: the temperature of the cooling oil increases, the temperature difference between the oil and the W-pin winding decreases, and the heat exchange efficiency decreases. Cooling oil outlet: The temperature of the cooling oil is close to the temperature of the conductor, resulting in low heat exchange efficiency.

[0032] Based on the above, a diaphragm 4 and an airbag 5 are respectively provided in the slot section 202 and the top section 201. Volume adjustment mechanisms are arranged in each key link of the W-pin winding to cover the entire length range of the winding with flow adjustment capability.

[0033] like Figure 6 As shown, there are three cases: a, b, and c. Case a corresponds to the stator winding 2 made of hollow conductors, in which no volume adjustment mechanism is provided. Cases b and c correspond to the stator winding 2 made of hollow conductors, in which a volume adjustment mechanism is provided. This volume adjustment mechanism divides the inner cavity of the stator winding 2 into two sub-channels. In addition, since the stator winding 2 is connected to an external cooling oil pump, the total flow rate of cooling oil into the cavity of the stator winding 2 remains constant. Therefore, in cases b and c, the airbag 5 only serves to change the distribution ratio of the two sub-channels.

[0034] b and c correspond to the deflation and inflation states of airbag 5, respectively. Clearly, the cooling oil flow rate on the other side during inflation is much higher than the cooling oil flow rate inside the stator winding 2 cavity when no volume adjustment mechanism is installed (reference). Figure 6 The shade of blue in the middle indicates the flow rate of the cooling oil.

[0035] Further reference Figure 7Based on the temperature distribution, the cooling oil flow rate in the cavity of stator winding 2 is divided into high-temperature side (slot opening side) and low-temperature side (slot bottom side). Here, a and b correspond to the scheme without diaphragm 4 and the scheme with diaphragm 4 but with airbag 5 in exhaust state, respectively. The flow rates on both sides are equally divided (the influence of diaphragm 4 and airbag 5 on the total flow rate (i.e., the sum of the flow rates on both sides) in exhaust state can be ignored). c to f correspond to the different expansion amounts of airbag 5 in the inflation state. It can be seen that airbag 5 only needs a deformation of 0.5 mm to increase the flow rate on one side to 97.7% of the total flow rate.

[0036] refer to Figure 8 The temperature of different areas in the cavity of stator winding 2 was detected. Taking the diaphragmless scheme 4 as the benchmark, it can be seen that the temperature gradually increases from the bottom of the slot to the top of the slot. When the diaphragm 4 is installed, although the temperature on the low-temperature side is 10℃ to 20℃ higher than that on the diaphragmless scheme 4, when the airbag 5 is inflated, the temperature on the high-temperature side decreases significantly compared to the diaphragmless scheme 4 due to the flow regulation, and the temperature change in the cavity is much smaller than that on the diaphragmless scheme 4.

[0037] In this embodiment, the diaphragm 4 is arranged along the length of the inner section 202 of the tank, and the airbag 5 is set on the side of the diaphragm 4 facing the bottom of the tank. When the temperature sensor detects that the temperature in this area is abnormally high, the host computer controls the external air source 6 to inflate the airbag 5, thereby reducing the cross-sectional area of ​​the inner cavity of the inner section 202 near the bottom of the tank, so that more cooling oil flows to the inner cavity near the stator slot opening, enhancing the cooling of the high temperature area of ​​the slot opening.

[0038] like Figure 9 As shown, the manufacturing method of this embodiment includes: S1. Stator core 1: 50DW470 non-oriented silicon steel sheets are stacked and formed, with a stacking coefficient ≥0.95; multiple stator slots are punched on the inner circumferential surface of stator core 1, which are flat-bottomed open slots.

[0039] S2. Use hollow conductors to make W-pin windings: Select hollow copper conductors with a flat rectangular inner cavity and a copper wall thickness of 1.0mm. Use continuous wave winding forming process to make W-pin windings. The hollow inner cavity of the conductor runs through the entire winding.

[0040] S3. Fabrication of diaphragm 4 and airbag 5 assembly: A flexible tubular diaphragm 4 is fabricated using a polyimide film with a wall thickness of 0.15 mm. A polyimide adhesive is coated on the edge of the diaphragm 4. A fluorosilicone rubber airbag 5 is laid at a predetermined position on the surface of the diaphragm 4. The airbag 5 is initially in a deflated, folded, and flat state with a fold thickness of 0.4 mm.

[0041] In an optional embodiment, refer to Figure 5 As shown, the sides of the diaphragm 4 are coated with adhesive base 401 at equal intervals.

[0042] S4. Guide wire insertion: Insert a 0.8mm diameter nickel-titanium shape memory alloy guide wire into one end of the hollow conductor. Utilize the self-guiding properties of the guide wire to pass through the W-pin curved inner cavity to the other end. Connect the front end of the folded diaphragm 4 airbag 5 assembly to the tail end of the guide wire with a snap fastener. Pull the guide wire at a constant speed from the other end of the conductor to pull the assembly to the predetermined cavity. Once in place, release the snap fastener and remove the guide wire.

[0043] S5. Localized induction heating fixation: A movable high-frequency induction heating coil is used to locally heat only the bonding area on the hollow conductor, so that the bonding area reaches the activation temperature. The area where the airbag 5 is located is not within the heating range of the induction coil. A water-cooling jacket is set on the outside of the airbag 5 area for auxiliary heat dissipation. Temperature measurement verification shows that the temperature of the airbag 5 area does not exceed 180°C, which is far below the 250°C temperature resistance limit of fluorosilicone rubber.

[0044] S6. Stator Embedding: After the W-pin winding cools to room temperature, insert insulating paper 3 into the stator slot; radially embed the W-pin winding into the stator slot of the stator core 1. Lead the gas pipeline of the air bag 5 along the embedded channel of the diaphragm 4 to the end of the W-pin winding, connect it with the gas channel of the composite end joint, and seal it with an O-ring.

[0045] S7. End Connection: Cut off excess W-pin winding ends and tighten the ends; laser weld the cooling oil channel of the composite end connector to the motor cooling oil channel. Lead the gas channel out through the seal through the motor end cover, install an oil-resistant fluororubber O-ring between the sealing flange of the seal and the end cover, and connect the outer end of the gas channel to the external gas source 6 main pipe.

[0046] It should be noted that any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0047] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0048] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A hollow conductor flat wire motor, comprising: The stator core and stator winding are provided. The stator core has a plurality of stator slots spaced circumferentially around the stator core. The stator winding is embedded in the stator slots. The stator winding is characterized in that the stator winding is a W-pin winding formed by bending and winding hollow conductors into a wave shape. The hollow conductors are connected to the external cooling oil circuit of the motor to form a liquid circulation channel. The corresponding coolant is driven by an external pump to flow in the liquid circulation channel and carry away the heat generated by the W-pin winding.

2. A hollow conductor flat wire motor according to claim 1, characterized in that, The W-pin winding is equipped with a volume adjustment mechanism. The W-pin winding has a composite end connector with mutually isolated cooling oil and gas channels. The cooling oil channel communicates with the inner cavity of the hollow conductor. The gas channel supplies gas to the volume adjustment mechanism in the inner cavity of the hollow conductor. The gas channel passes through a seal and leads out to the outside of the motor through the motor end cover. The volume adjustment mechanism includes: a diaphragm arranged in the inner cavity of the stator winding. The diaphragm has multiple air bladders on at least one side. The air bladders on the same side are interconnected and connected to an external gas source. The air bladders on different sides are not interconnected. Gas is introduced through the gas channel of the composite end connector. When the temperature on one side of the diaphragm rises abnormally, the external gas source inflates the air bladders on the side away from the abnormally high temperature of the diaphragm to reduce the inner cavity volume of the stator winding on the side away from the abnormally high temperature. This increases the total amount of cooling oil that can be accommodated in the inner cavity of the stator winding facing the abnormally high temperature, thereby improving the cooling efficiency on the side with the abnormally high temperature.

3. A hollow conductor flat wire motor according to claim 2, characterized in that, It also includes a control system, which includes a temperature sensor and a host computer. The temperature sensor is configured to acquire temperature data of the diaphragm deployment area and transmit the temperature data to the host computer, thereby the host computer adjusting the inflation volume of the external air source in response to the temperature data.

4. A hollow conductor flat wire motor according to claim 3, characterized in that, The W-pin winding includes: an in-slot section located in the stator slot and a top section and a bottom section located at the top and bottom of the stator slot, respectively, wherein the in-slot section and the top section are respectively provided with the diaphragm and the air bag.

5. A hollow conductor flat wire motor according to claim 4, characterized in that, The diaphragm is arranged along the length of the slot section, and the airbag is located on the side of the diaphragm facing the bottom of the slot. When the temperature sensor detects that the temperature of the diaphragm facing the stator slot opening is abnormally high, the host computer controls the external air source to inflate the airbag to expand it, thereby reducing the internal cavity volume of the stator winding near the bottom of the stator slot. This increases the total amount of cooling oil that can be accommodated in the internal cavity of the stator winding near the stator slot opening, thereby improving the cooling efficiency of the side near the stator slot opening.

6. A hollow conductor flat wire motor according to claim 4, characterized in that, The volume adjustment mechanism is located at the junction of the top section and the inner section of the groove.

7. A hollow conductor flat wire motor according to claim 6, characterized in that, The diaphragm is positioned perpendicular to the horizontal plane at the junction of the top section and the slot section, and the airbag is positioned on the side of the diaphragm facing the outer wall of the stator winding.

8. A hollow conductor flat wire motor according to claim 2, characterized in that, The diaphragm, centrally positioned, divides the inner cavity into two sub-channels; the cooling oil in the sub-channels flows in a laminar flow state; after the airbag is inflated, the flow rate of the sub-channel on the side with abnormally high temperature increases... satisfy: ,in This is the initial height of the sub-channel. This refers to the airbag inflation volume.

9. A method for manufacturing a hollow conductor flat wire motor, used to manufacture a hollow conductor flat wire motor as described in any one of claims 2 to 8, characterized in that, Includes the following steps: S1. Making the stator core; S2. Hollow conductors are selected to make the W-pin winding; S3. Fabricate a diaphragm and airbag assembly with an edge coated with a heat-capacity adhesive layer, wherein the airbag assembly is initially in a deflated, folded, flat state; S4. Insert the folded diaphragm and airbag assembly into the hollow conductor through the guide wire from one end of the hollow conductor and pull it along the inner cavity of the conductor to the predetermined cavity; the guide wire is pre-arranged along the inner cavity of the W-pin winding; the diaphragm is a flexible tubular structure that can slide into place along the inner cavity of the bending. S5. Heating the predetermined cavity section of the hollow conductor equipped with the diaphragm and airbag assembly, so that the heat-capacitance adhesive layer coated on the edge of the diaphragm and airbag assembly is activated by heat and bonded to the inner wall of the hollow conductor. S6. After the W-pin winding cools down to room temperature, insert insulating paper into the stator slot and then radially embed the W-pin winding into the stator core slot; lead the gas pipeline of the airbag along the diaphragm embedded channel to the end of the W-pin winding and seal it with the gas channel of the composite end joint. S7. Cut off the excess W-pin winding ends, tighten the ends, weld the cooling oil channel of the composite end connector to the motor cooling oil channel, and lead the gas channel out through the seal through the motor end cover and connect it to the external gas source main pipe.

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