Stair oil injection and skewed slot diversion collaborative cooling stator system

Abstract

The invention discloses a cascade oil injection and skewed slot diversion collaborative cooling stator system, which comprises a stator core, the annular channels are sequentially and axially arranged in the circumferential direction of the stator iron core, and each annular channel is arranged in the stator iron core and inclines relative to the axial direction of the stator iron core at a preset inclination angle; the stator iron core radial cooling channel is arranged on the outer wall of the stator iron core and is communicated with the annular channel; the stator iron core axial cooling channel is arranged on the outer wall of the stator iron core and is communicated with the stator iron core radial cooling channel; the shell is wrapped outside the stator iron core; the first step oil injection ring is connected with the stator iron core, first oil injection holes which are axially staggered are formed in the circumferential direction of the first step oil injection ring, and the first step oil injection ring is communicated with the annular groove channel and the stator iron core axial cooling groove channel; and the second step oil injection ring is connected with the stator iron core, and second oil injection holes which are axially staggered are formed in the circumferential direction of the second step oil injection ring and are communicated with the annular groove channel and the stator iron core axial cooling groove channel. The heat exchanger can realize uniform heat control distribution and is high in heat exchange efficiency.

Description

Technical Field

[0001] This invention belongs to the field of motor thermal management technology, specifically relating to a stator system that combines stepped oil injection with inclined slot flow for coordinated cooling. Background Technology

[0002] With the rapid development of new energy construction machinery and heavy-duty electric drive systems, the power density and current density of motors are continuously increasing, bringing extremely high heat flux density and thermal control challenges. Especially under high-frequency start-stop and high-torque output operating conditions, the stator core and windings of the drive motor are prone to generating a large amount of heat. If heat cannot be dissipated in a timely and effective manner, it can easily lead to problems such as inter-turn insulation aging, thermal breakdown, and electromagnetic performance degradation, seriously affecting motor performance and service life. Therefore, how to achieve full-area, uniform, and efficient heat dissipation of the stator and its windings has become one of the core challenges in the thermal management of electric drive systems for construction machinery.

[0003] Currently, in engineering practice, solutions such as oil spray cooling, oil channel heat conduction, or water-cooled jackets are commonly used to address the heat dissipation requirements of motors. For example, some solutions involve setting oil spray rings at both ends of the stator to cool the windings and core by spraying oil mist onto the stator ends. However, these solutions suffer from problems such as limited oil coverage, large temperature differences between turns, and uneven oil spraying. Another solution involves designing axial oil channels on the outer ring of the stator core to guide the oil to flow along the core surface for heat exchange. However, this mainly acts on the outer area of ​​the stator and is difficult to penetrate deep into the winding layers to provide effective cooling. While some highly integrated solutions propose structural optimizations, they often only address cooling in a single direction and have not yet formed a synergistic cooling system covering the entire stator area.

[0004] Chinese invention patent application CN119696216A discloses a heat dissipation structure for an oil-cooled motor stator, comprising a stator core, a flow divider ring, and an oil injection assembly arranged sequentially along the axial direction. Multiple axially extending cooling oil channels are evenly distributed on the outer peripheral wall of the stator core. Multiple transition channels communicating with the cooling oil channels are evenly distributed circumferentially on the flow divider ring. Multiple first and second oil injection channels are evenly distributed circumferentially on the oil injection assembly, with the axes of the first and second oil injection channels not at the same angle to the axis of the stator core. A guide is provided within the transition channels. When the cooling oil flow rate in the transition channels is less than a threshold, the guide restricts the flow of cooling oil from entering the first oil injection channel. When the cooling oil flow rate in the transition channels is greater than the threshold, the cooling oil in the transition channels can overcome the restriction of the guide and flow into the first oil injection channel. This invention can change the spray angle of the cooling oil to achieve a better cooling effect. This scheme proposes an oil-cooled stator structure that can automatically adjust the injection path according to the cooling oil flow rate. Dynamic adjustment of the injection angle is achieved by setting first and second injection channels with different axial angles and flow rate-sensitive guides. However, the flow regulation mechanism of this structure is essentially a "passive response" switching based on the fluid kinetic energy, which cannot provide a wider spatial coverage and more uniform inter-turn heat exchange under complex operating conditions (such as sudden heavy load changes and intermittent thermal shock). Furthermore, its injection system is relatively isolated from the cooling structure of the stator core, lacking active optimization path control for the heat exchange process between the core and the shell. The overall guide-injection-discharge process coupling is low, and the oil utilization efficiency still needs improvement.

[0005] Chinese invention patent application CN119628266A discloses an oil-cooled motor stator structure, including a winding and a stator core. The winding is inserted into the stator core, and a cooling jacket is provided outside the stator core. The cooling jacket has multiple annular oil passages inside, each annular oil passage reciprocates along the axial direction, and adjacent annular oil passages are interconnected. Multiple oil spray holes are evenly spaced along the outer edges of both ends of the cooling jacket. The multiple oil spray holes are arranged in an arc shape, and the angle between the oil spray holes at both ends of the arc and the center is 60° to 180°. The annular oil passages at both ends are connected to the oil spray holes. This invention utilizes a cooling jacket surrounding the stator core, with multiple axially reciprocating annular oil channels within the jacket. The oil is ultimately sprayed from injection holes. These annular oil channels increase the heat exchange area of ​​the stator core, resulting in high heat dissipation efficiency. Furthermore, this stator structure is a novel, low-cost, end-balanced cooling structure. By changing the oil inlet, the upper and lower oil distribution paths within the casing can be adjusted to reduce flow resistance differences, leading to better spraying effects and greater adaptability. The stator jacket-type oil-cooling structure proposed in this solution, by setting multiple axially reciprocating annular oil channels around the stator and arranging the injection holes in an arc shape to achieve end coverage, possesses good structural simplicity and enhanced local heat dissipation capabilities. However, the annular oil channels in this technology are located within the outer cooling jacket of the stator, creating a certain heat conduction path with the windings and the core body, resulting in delayed thermal response and a large temperature gradient, which is detrimental to inter-turn temperature difference control. Its fuel injection structure is mainly based on "fixed point-arc surface" spraying, lacking a layered staggered spatial atomization design. Under high-speed rotation or oil mist reaction field, it is prone to forming "impact dead zone" or overlapping spray zone, thereby reducing the overall uniformity of oil coverage and dynamic adaptability. In addition, the oil circuit and fuel injection hole structure are still segmented, and the integration and thermal path coordination need to be improved.

[0006] Chinese invention patent application CN119742972A discloses a heat dissipation structure for an oil-cooled motor stator core surface oil-cooling circuit, belonging to the field of oil-cooled motor stators, including end face laminations and intermediate laminations. Compared to existing technologies, this invention involves sequentially and alternately welding the end face laminations and intermediate laminations along the axial direction during manufacturing. When installed with the housing, the housing has an interference fit with this invention, sealing the oil passage and eliminating sealing components such as oil rings, thus reducing costs. Simultaneously, several oil-blocking blocks on the intermediate laminations are interference-fitted with the housing, forming a circuit between the oil-blocking blocks. When cooling oil enters from the oil inlet of the housing, it flows in all directions along the formed circuit, effectively increasing the flow rate of the cooling oil and ensuring sufficient contact between the cooling oil and the iron core for cooling, thereby improving the cooling effect. This solution, by arranging the stator end face laminations and intermediate laminations alternately and placing oil-blocking blocks on the laminations, forms a closed circuit with the housing through an interference fit, thus eliminating traditional sealing components and improving manufacturing simplicity and economy. While this structure offers advantages in simplifying manufacturing processes and increasing oil circulation rates, its cooling oil channels are planar, fitted loops that primarily flow along the two-dimensional plane of the iron core's outer surface. Lacking effective turbulence or guidance mechanisms, it struggles to achieve deep heat transfer into the windings, between turns, or along the axial direction under high-speed, high-heat-flux-density conditions. Furthermore, the oil path relies entirely on lamination stacking, limiting geometric freedom and making it difficult to differentiate heat conduction paths based on heat source distribution. The overall cooling structure still exhibits significant shortcomings in multi-scale, layered control. Summary of the Invention

[0007] To address the aforementioned problems, this invention proposes a stator cooling system that combines stepped oil injection with inclined channel flow, which can achieve uniform heat control distribution and high heat exchange efficiency.

[0008] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0009] This invention provides a stator system for coordinated cooling by stepped oil injection and inclined slot flow, comprising:

[0010] Stator core;

[0011] Several annular channels are arranged axially along the circumference of the stator core. Each annular channel is located inside the stator core and is inclined at a preset angle relative to the axial direction of the stator core.

[0012] The stator core radial cooling channels are arranged on the outer wall of the stator core along the circumference of the stator core and are connected to each annular channel respectively.

[0013] The stator core axial cooling channel is arranged along the axial direction of the stator core on the outer wall of the stator core and is connected to the stator core radial cooling channel.

[0014] The housing, which encloses the outside of the stator core;

[0015] The first-stage oil injection ring is connected to the first end of the stator core. It has an axially offset first oil injection hole in the circumferential direction and is connected to the annular channel and the axial cooling channel of the stator core.

[0016] The second-stage oil injection ring is connected to the second end of the stator core. It has an axially offset second oil injection hole in the circumferential direction and is connected to the annular channel and the axial cooling channel of the stator core.

[0017] Optionally, the stator core is provided with a plurality of stator slots in the circumferential direction;

[0018] The stepped oil injection and inclined slot flow-guided co-cooling stator system further includes: several sets of windings, each winding is embedded in a corresponding stator slot, and an insulating layer is provided between them, the thermal conductivity of the insulating layer is greater than a set thermal conductivity threshold.

[0019] The exposed area at the end of the winding serves as a heat exchange interface, and the cooling oil injected from the first and second oil injection holes is directed toward the heat exchange interface.

[0020] Optionally, the external cooling oil first enters the radial cooling channel of the stator core; then it is sent from the radial cooling channel to the axial cooling channel and each annular channel of the stator core, and guided by the axial cooling channel and each annular channel to the first and second stage oil injection rings for axial-tangential composite flow guidance; then it is sprayed onto the winding through the first and second oil injection holes; finally, it is recovered by the oil drain port on the housing, forming a complete flow guidance-oil injection-oil drain cooling closed-loop system.

[0021] Optionally, the first-stage oil injection ring adopts a stepped structure in the circumferential direction, including several first steps arranged in a stepped manner along the circumferential direction of the first-stage oil injection ring. Each first oil injection hole is arranged in layers on the corresponding first step in an axially staggered manner to form a first multi-layer oil injection hole array for realizing multi-stage spray cooling.

[0022] The second-stage injection ring adopts a stepped structure in the circumferential direction, including several second steps arranged in a stepped manner along the circumferential direction of the second-stage injection ring. Each second injection hole is arranged in layers on the corresponding second step in an axially staggered manner to form a second multi-layer injection hole array for multi-stage spray cooling.

[0023] Optionally, the oil jets sprayed from the first and second stage oil injection rings are distributed in a mist, cone, or fan shape, and the oil jets uniformly cover the heat-sensitive areas of the winding ends and stator core end faces.

[0024] Optionally, the diameter of the first injection hole is 0.6~1.2mm; the diameter of the second injection hole is 0.6~1.2mm.

[0025] Optionally, the injection ring is also provided with a filter and an anti-backflow stop.

[0026] Optionally, the cross-section of each annular channel is sloping or curved.

[0027] Optionally, each annular channel is inclined at an angle of 3 to 5° relative to the axial direction of the stator core.

[0028] Optionally, the stator core adopts a multi-layer lamination structure, and the multi-layer laminations are welded and fixed at the axial cooling channels of the stator core.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] This invention provides a stator cooling system that combines stepped oil injection and inclined slot flow guidance. By creating multiple annular channels distributed axially within the stator core, it achieves composite turbulent flow of cooling oil in both the axial and tangential directions, improving the overall heat exchange efficiency between the shell and the stator core. Simultaneously, the first and second stepped oil injection rings at both ends of the stator core are arranged in a circumferential stepped structure, with the injection holes arranged in a layered, axially staggered manner to form mist / conical oil jets. This achieves multi-layered, full-area spray cooling of the winding ends, enhancing the uniformity of heat exchange between turns. The combined effect of these two systems constructs an integrated "guide-spray-drain" synergistic heat dissipation path, improving the response speed and control accuracy of the thermal management system and enabling uniform heat distribution.

[0031] This invention is adaptable to oil-cooled electric drive platforms with various power levels and housing size constraints, and is especially suitable for applications with high heat flux density and frequent changing operating conditions, such as engineering machinery. It significantly improves the system's heat dissipation efficiency while ensuring the thermal safety of the windings, and has significant novelty, creativity and practical engineering value. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0033] Figure 1 This is a schematic diagram of the stator system structure proposed in this invention, which combines stepped oil injection with inclined slot flow guidance for coordinated cooling.

[0034] Figure 2 This is a schematic diagram of the inclined slot annular flow guiding stator core structure proposed in this invention;

[0035] Figure 3 This is a schematic diagram of the crown-end stepped fuel injection ring structure proposed in this invention;

[0036] Figure 4 This is a schematic diagram of the stepped oil spray ring structure at the welding end proposed in this invention;

[0037] Figure 5 This is a schematic diagram of the cascaded oil injection and inclined groove flow-guided synergistic cooling oil passage structure proposed in this invention;

[0038] Explanation of reference numerals in the attached drawings: 1. Stator core; 2. Cooperative cooling oil channel; 3. First-stage oil injection ring; 4. Second-stage oil injection ring; 5. Winding; 11. Interference fit surface between stator core and housing; 12. Axial cooling channel of stator core; 13. Radial cooling channel of stator core; 14. Annular channel; 15. Stator slot; 21. Cooling oil inlet channel; 22. Radial cooling oil channel of core; 23. Axial cooling oil channel of core; 24. Inclined groove type oil guide channel; 25. First oil injection ring oil guide channel; 26. Second oil injection ring oil guide channel; 31. First oil injection hole; 32. First step; 41. Second oil injection hole; 42. Second step. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may include different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0041] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0042] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "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 invention. In this specification, the illustrative expressions of the above terms do not necessarily refer 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.

[0043] The application principle of the present invention will be described in detail below with reference to the accompanying drawings.

[0044] like Figure 1 As shown, this invention provides a stator system for coordinated cooling by stepped oil injection and inclined slot flow, comprising:

[0045] Stator core 1;

[0046] Several annular channels 14 are arranged axially along the circumferential direction of the stator core 1. Each annular channel 14 is located inside the stator core 1 and is inclined relative to the axial direction of the stator core 1 at a preset angle.

[0047] The stator core radial cooling channels 13 are arranged on the outer wall of the stator core 1 along the circumferential direction of the stator core 1, and are respectively connected to each annular channel 14;

[0048] The stator core axial cooling channel 12 is arranged on the outer wall of the stator core 1 along the axial direction of the stator core 1 and is connected to the stator core radial cooling channel 13.

[0049] The housing surrounds the stator core 1; the housing and the stator core radial cooling channel 13 together form the core radial cooling oil channel 22; the housing and the stator core axial cooling channel 12 together form the core axial cooling oil channel 23; in specific implementation, the housing and the stator core 1 are interference fit, and there is an interference fit surface 11 between the stator core 1 and the housing.

[0050] The first-stage oil spray ring 3 is connected to the first end of the stator core 1. It has an axially offset first oil spray hole 31 in its circumferential direction and is connected to the annular channel 14 and the stator core axial cooling channel 12. Figure 1 As shown, through

[0051] The second-stage oil spray ring 4 is connected to the second end of the stator core 1. It has an axially offset second oil spray hole 41 in the circumferential direction and is connected to the annular channel 14 and the stator core axial cooling channel 12.

[0052] In the above scheme, a closed circumferential and axial oil guide cavity is formed between the shell and the stator core 1. It is combined with the radial cooling oil channel 22 of the core (formed by the shell and the radial cooling channel 13 of the stator core), the axial cooling oil channel 23 of the core (formed by the shell and the axial cooling channel 12 of the stator core), and the inclined groove type oil guide channel 24 (i.e., the annular channel 14) to form a collaborative cooling oil channel 2, which completes the axial-tangential composite flow of the oil. After cooling the stator core 1, the cooling oil is sprayed to cool the ends of the winding 5, forming a complete "flow guidance-oil spraying-oil return" cooling closed loop system. Specifically, by creating multiple annular channels 14 distributed along the axial direction of the stator core 1 inside the stator core 1, a composite turbulent flow of cooling oil in the axial and tangential directions is achieved, improving the overall heat exchange efficiency between the shell and the stator core 1. Simultaneously, the first-stage oil spray rings 3 and the second-stage oil spray rings 4 at both ends of the stator core 1 are arranged in a circumferentially stepped structure, with the oil spray holes arranged in a layered manner according to axial staggered patterns, forming a mist / conical oil jet. This achieves full-area multi-layer spray cooling of the winding ends 5, enhancing the uniformity of heat exchange between turns. The two work together to construct an integrated "guide-spray-exhaust" coordinated heat dissipation path, improving the response speed and control accuracy of the thermal management system. More specifically, the external cooling oil first enters the stator core radial cooling channel 13; then it is fed from the stator core radial cooling channel 13 into the stator core axial cooling channel 12 and each annular channel 14, and guided by the stator core axial cooling channel 12 and each annular channel 14 to the first stage oil injection ring 3 and the second stage oil injection ring 4 for axial-tangential composite flow guidance; then it is sprayed onto the winding 5 through the first oil injection hole 31 and the second oil injection hole 41; finally, it is recovered by the oil drain port on the housing, forming a complete flow guidance-oil injection-oil drain cooling closed-loop system.

[0053] In one specific embodiment of the present invention, the stator core 1 is provided with a plurality of stator slots 15 in the circumferential direction;

[0054] The stepped oil injection and inclined slot flow-guided co-cooling stator system further includes: several sets of windings 5, each winding 5 is embedded in the corresponding stator slot 15, and an insulating layer is provided between them, the thermal conductivity of the insulating layer is greater than the set thermal conductivity threshold.

[0055] The exposed area at the end of winding 5 serves as a heat exchange interface, and the cooling oil sprayed from the first oil injection hole 31 and the second oil injection hole 41 is directed toward the heat exchange interface.

[0056] In the above scheme, by setting a high thermal conductivity insulating pad between the winding 5 and the stator core 1, structural isolation is achieved while maintaining good thermal coupling performance, ensuring that the sprayed oil can effectively remove heat between the turns. In specific implementation, the winding 5 can be an 8-layer or more concentrated flat wire winding 5.

[0057] In a specific embodiment of the present invention, the first stepped oil injection ring 3 is arranged in a stepped structure in the circumferential direction, including a number of first steps 32 arranged in a stepped manner along the circumferential direction of the first stepped oil injection ring 3. Each first oil injection hole 31 is arranged in layers on the corresponding first step 32 in an axially staggered manner to form a first multi-layer oil injection hole array for realizing multi-stage spray cooling.

[0058] The second-stage oil injection ring 4 adopts a stepped structure in the circumferential direction, including several second steps 42 arranged in a step-like manner along the circumferential direction of the second-stage oil injection ring 4. Each second oil injection hole 41 is arranged in layers on the corresponding second step 42 in an axially staggered manner to form a second multi-layer oil injection hole array for realizing multi-stage spray cooling.

[0059] In the above scheme, the size and spray angle of the first and second oil injection holes 31 can be optimized according to the location of the heat-sensitive area to achieve directional oil spraying cooling for high hot spots between turns, while avoiding oil "penetrating" the insulation layer or causing flow short circuits. Each oil injection hole has a certain axial spacing, forming a continuous "multi-segment oil injection-multi-segment drainage" link to achieve coordinated spraying and drainage. In specific implementation, the first and second oil injection rings can be integral machined parts or welded components, preferably made of oil-resistant alloys or high-temperature and high-pressure resistant plastics to ensure oil spraying stability and system reliability. The first and second oil injection rings are positioned near the end of winding 5 and have a closed annular structure.

[0060] In a specific embodiment of the present invention, the oil jets sprayed by the first stage oil injection ring 3 and the second stage oil injection ring 4 are distributed in a mist, cone or fan shape, and the oil jets uniformly cover the heat-sensitive area of ​​the end of the winding 5 and the end face of the stator core 1.

[0061] Based on the above solution, the uniformity of fuel injection can be effectively improved, and the inter-turn heat exchange can be significantly enhanced, thus overcoming the problem of spray blind spots caused by traditional symmetrical arrangements.

[0062] In one specific embodiment of the present invention, the diameter of the first oil injection hole 31 is 0.6~1.2mm; the diameter of the second oil injection hole 41 is 0.6~1.2mm.

[0063] Based on the above solution, it is possible to effectively prevent the oil from "penetrating" the insulation layer or causing a flow short circuit.

[0064] In one specific embodiment of the present invention, the oil injection ring is further provided with a filter and an anti-backflow stop.

[0065] Based on the above design, fuel injection stability and system reliability can be guaranteed.

[0066] In one specific embodiment of the present invention, the cross-section of each annular channel 14 is a slope or a curved surface.

[0067] Based on the above design, the oil can be guided to achieve axial and tangential combined flow between the shell and the stator core 1. The annular channel 14 can flexibly adjust its width, depth, and inclination angle according to the heat load distribution, forming multiple turbulence pitches (for example, an annular channel 14 with a rectangular cross-section has several sequentially arranged rectangular segments due to the inclination angle), effectively enhancing the oil turbulence and heat transfer efficiency at the shell-core interface, and improving the overall heat exchange capacity of the core. In specific implementation, the cross-section of the annular channel 14 can be circular, rectangular, etc., and can be set according to actual needs.

[0068] In one specific embodiment of the present invention, each annular channel 14 is inclined at an angle of 3 to 5° relative to the axial direction of the stator core 1.

[0069] Based on the above scheme, a composite axial and tangential flow path can be effectively formed.

[0070] In one specific embodiment of the present invention, the stator core 1 adopts a multi-layer lamination structure, and the multi-layer laminations are welded and fixed at the axial cooling channel 12 of the stator core.

[0071] In summary, this invention drives cooling oil into the radial cooling channel 13 of the stator core via an external oil pump. The oil undergoes axial-tangential composite flow guidance along the annular channel 14 and the axial cooling channel 12 of the stator core within the housing cavity, forming a large-area heat exchange surface with the outer wall of the stator core 1, thereby increasing the overall heat flux of the stator. The oil then rapidly flows to the oil spray rings on both sides, achieving multi-stage spray cooling through axial layered oil spray holes. The oil jet evenly covers the heat-sensitive areas at the ends of the winding 5 and the end face of the core, and is finally discharged through a designated channel and recycled back to the oil circulation system.

[0072] In this invention, the annular channel 14 and the stepped structure oil injection ring complement each other. The former provides a distributed heat conduction channel for the stator core 1, which can quickly remove the heat dissipated by the core and the straight section winding 5. The latter achieves layered and precise cooling of the end winding 5. The two construct an integrated cooling path with high response, high adaptability and high efficiency, which can significantly improve the thermal management capability of the oil-cooled electric drive system without significantly increasing the structural complexity.

[0073] It has the following beneficial effects:

[0074] (1) Construct a composite conductive path to achieve efficient heat exchange of stator core 1.

[0075] By utilizing the annular channel 14 opened on the stator core 1, an axial and tangential composite disturbance flow path is formed, which can effectively break the oil film laminar flow boundary between the stator core 1 and the shell, significantly improve the heat transfer coefficient of the end face area, reduce the average thermal resistance of the stator yoke by more than 20%, and effectively alleviate the problem of end heat accumulation under high heat flux density conditions.

[0076] (2) Achieve multi-layer inter-turn spray coverage to enhance the local cooling capacity of winding 5.

[0077] By setting a first-stage oil spray ring and a second-stage oil spray ring 4 at the crown end and welding end of the stator core 1, and axially staggering the oil spray holes, a cone-shaped or mist-like multi-layered oil jet is formed, which can achieve full coverage of the 5 turns of the end winding, the inter-turn layers and the exposed copper edge of the inner layer. The maximum temperature difference between the 5 turns of the winding is reduced by more than 20%, which significantly suppresses the risk of hot spot formation and local over-temperature failure.

[0078] (3) Integrating a “guide-spray-exhaust” integrated collaborative cooling path to improve the system’s thermal control response speed.

[0079] The annular channel 14 and the stepped oil injection ring form a structurally integrated channel, and the heat flow forms a complete path from the gap of the iron core shell → iron core end face → winding 5 end → oil outlet; compared with the traditional isolated spray system, the cooling path response speed of the present invention is improved by more than 30%, and it has good thermal stability and working condition adaptability.

[0080] (4) High structural integration, adaptable to the compact space design requirements of electric drive.

[0081] All cooling structures of this invention are machined within the existing stator core 1 and oil injection assembly, without increasing the axial length of the stator or the size of the housing, thus possessing good spatial compatibility and a compact structure, making it suitable for volume-constrained platforms such as new energy engineering machinery and commercial vehicle electric drive axles.

[0082] (5) Applicable to various heavy-duty electric drive application scenarios, enhancing the core competitiveness of motor systems.

[0083] This invention is particularly suitable for high-load, high-frequency, and high-thermal-shock scenarios, such as new energy mining trucks, electric heavy trucks, and traction electric drive axles. It solves the pain points of traditional oil injection cooling, such as many blind spots, weak core heat exchange, and slow thermal control response. It has significant technological advantages and market application prospects.

[0084] The following detailed description of the stator system of the present invention, which combines stepped oil injection and inclined slot flow guidance, is based on a specific embodiment.

[0085] like Figure 1 As shown, the stepped oil spraying and inclined slot guide cooling stator system mainly includes: stator core 1, winding 5, and co-cooling oil channel 2. The annular channel 14 forms an inclined slot type oil guide channel 24. The co-cooling oil channel 2 is formed by the core radial cooling oil channel 22 (formed by the shell and the stator core radial cooling channel 13), the core axial cooling oil channel 23 (formed by the shell and the stator core axial cooling channel 12), and the inclined slot type oil guide channel 24. The stator core 1 is provided with a first oil spraying ring 3 and a second oil spraying ring 4 at both ends (crown end and welded end). The first oil spraying ring 3 is provided with a first oil spraying ring guide channel 25, and the second oil spraying ring 4 is provided with a second oil spraying ring guide channel 26. The key technical points of this stepped oil spraying and inclined slot flow-guided co-cooling stator system are as follows: the stator core 1 is provided with annular channels 14 arranged axially along the circumference of the stator core 1, and there is an angle between the axial direction of the annular channels 14 and the axial direction of the stator core 1, and the oil flow direction is a composite flow of axial and tangential directions; the oil spraying rings at both ends of the stator core 1 are arranged in a stepped manner in the circumferential direction, and the oil spraying holes are distributed in a multi-layered manner with axial offset, and the two work together to construct an integrated heat dissipation path of "guide-spray-exhaust".

[0086] like Figure 2 As shown, the stator core 1 has a 54-slot embedded structure, made of high-permeability, low-loss silicon steel sheets laminated together, with an axial length of 160mm and an inner diameter of 240mm. Several annular channels 14 are machined internally, arranged axially along the circumference of the stator core 1. The slot diameter of the annular channels 14 is preferably 1-2mm, and the number of annular channels 14 corresponds to the number of stator slots 15. The annular channels 14 are continuously arranged circumferentially and inclined at an angle of 3-5° relative to the axial direction, thus forming a combined axial and tangential flow path. This structure enhances the local heat transfer efficiency between the shell and the stator core through flow disturbance. Furthermore, the slot spacing and inclination angle of the annular channels 14 can be regionalized according to the stator hot spot distribution, exhibiting high adjustability and adaptability.

[0087] like Figure 3 and Figure 4 As shown, the first oil spray ring 3 (located at the crown end) and the second oil spray ring 4 (located at the welding end) are arranged in a multi-layered stepped structure. Several first oil spray holes 31 and second oil spray holes 41 are provided on the selected first step 32 and second step 42. The diameters of the first oil spray holes 31 and second oil spray holes 41 are controlled within the range of 0.6~1.2mm, and they are arranged in staggered layers along the axial direction of the oil spray rings, so that the sprayed oil jet is in a conical diffusion state, effectively enveloping the five turns of the winding and its ends. The stepped structure forms a multi-layered mist-like oil spray zone, improving the uniformity of oil spraying and significantly enhancing inter-turn heat exchange, thus overcoming the spray blind zone problem caused by traditional symmetrical arrangements.

[0088] like Figure 5 As shown, the annular channel 14 forms an inclined groove-type oil guide channel 24. The radial cooling oil channel 22 of the iron core, the axial cooling oil channel 23 of the iron core, and the inclined groove-type oil guide channel 24 are connected to form a synergistic cooling oil channel 2, thus constructing a complete "guide-spray-drain" synergistic cooling path. The specific process is as follows: Cooling oil is driven into the cooling oil inlet channel 21 by an external oil supply pump. The cooling oil inlet channel 21 is connected to the co-cooling oil channel 2. Therefore, the cooling oil enters the co-cooling oil channel 2 through the cooling oil inlet channel 21 and is quickly discharged in the co-cooling oil channel 2. Then, it is axially guided along the inclined groove-shaped oil guide channel 24 to form a large area heat exchange surface with the iron core, thereby improving the overall heat flux of the stator. Then, the oil flows rapidly to the first oil spray ring 3 and the second oil spray ring 4 on both sides, and flows into the first oil spray ring guide channel 25 inside the first oil spray ring 3 and the second oil spray ring guide channel 26 inside the second oil spray ring 4. Multi-stage spray cooling is achieved by the axially layered first oil spray hole 31 and second oil spray hole 41. The oil jet evenly covers the heat-sensitive area of ​​the winding 5 end and the iron core end face. Finally, it is discharged through the set channel and recycled to the oil circulation system.

[0089] In conclusion:

[0090] This invention provides a stator cooling system that combines stepped oil injection and inclined slot flow guidance, suitable for heavy-duty electric drive systems. By arranging annular channels inside the stator core and setting a first stepped oil injection ring and a second stepped oil injection ring with axially misaligned oil injection holes at both ends of the stator core, a highly efficient synergistic cooling path integrating oil guidance, oil injection, and oil discharge is constructed. This achieves multi-faceted heat dissipation of the windings, rapid hot spot removal, and balanced control of stator temperature rise. It is suitable for electric drive systems with high heat flux density and frequent start-stop under high loads, such as engineering machinery.

[0091] In this invention, several annular channels are sequentially distributed axially along the circumference inside the stator core. These annular channels penetrate the outer circumferential surfaces at both ends of the stator core. The bottom of each annular channel has a specific inclination angle. The spacing between adjacent annular channels and the inclination angle can be adjusted according to the stator load heat distribution, thereby guiding the oil to flow in both axial and tangential directions, improving the heat exchange efficiency between the stator core and the shell. The inclined groove structure of the annular channels helps the oil to fully cover the outer hot surface of the stator core and forms an effective heat exchange channel with the shell.

[0092] In this invention, a first-stage oil spray ring and a second-stage oil spray ring are respectively provided at both ends of the stator core. Both the first-stage and second-stage oil spray rings adopt a circumferentially stepped structure. The oil spray holes are staggered in layers along the axial direction of the stepped oil spray rings, so that the sprayed oil jet is mist-like or conical, covering different turns of the winding layer by layer, realizing multi-dimensional cooling between turns. This structure significantly improves the coverage and uniformity of oil spray cooling.

[0093] In this invention, the annular channel, the first-stage oil injection ring, and the second-stage oil injection ring form an integrated "guide-spray-exhaust" synergistic cooling path. Cooling oil first enters the annular channel, then is guided through the channel to the first-stage and second-stage oil injection rings on both sides, and is then sprayed onto the winding surface through injection holes. Finally, it is recovered through the exhaust port located on the housing, forming a closed-loop, high-efficiency cooling circuit. This path possesses high thermal response speed and temperature rise regulation capability, adapting to the continuous thermal control requirements under high-speed, high-frequency start-stop conditions.

[0094] In this invention, the annular cooling channel, the radial cooling channel of the stator core, and the axial cooling channel of the stator core are all arranged in the non-working area or interference fit area of ​​the electronic core, which does not affect the integrity of the motor's magnetic circuit and mechanical strength, ensuring the synergistic unity of structural reliability and cooling efficiency. This structure can achieve high-density cooling path integration without significantly increasing the motor's volume or damaging its electromagnetic performance.

[0095] This invention adopts a modular design and has high integration characteristics. It is suitable for space-constrained and compact engineering machinery electric drive platforms. The stepped oil injection ring and the annular channel can be manufactured separately and assembled, which facilitates mass production and maintenance replacement.

[0096] The present invention has excellent sealing performance. The oil injection ring and the annular channel are stably connected by threads, sealing rings or high-temperature sealant, which can adapt to high-pressure oil flow conditions, prevent oil leakage and reduction of oil injection efficiency, and at the same time have good vibration resistance.

[0097] This invention has the ability to cool the entire area under heavy load conditions with high heat flux density. It is suitable for high-performance oil-cooled electric drive systems with current density greater than 25A / mm² and temperature rise limit less than 100°C. It can control the temperature difference of stator hot spots within 20°C, significantly extend winding life, and improve the thermal safety margin of the electric drive system.

[0098] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of the present invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the present invention.

[0099] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A stator system for coordinated cooling by stepped oil injection and inclined slot flow guidance, characterized in that, include: Stator core; Several annular channels are arranged axially along the circumference of the stator core. Each annular channel is located inside the stator core and is inclined at a preset angle relative to the axial direction of the stator core. The stator core radial cooling channels are arranged on the outer wall of the stator core along the circumference of the stator core and are connected to each annular channel respectively. The stator core axial cooling channel is arranged along the axial direction of the stator core on the outer wall of the stator core and is connected to the stator core radial cooling channel. The housing, which encloses the outside of the stator core; The first-stage oil injection ring is connected to the first end of the stator core. It has an axially offset first oil injection hole in the circumferential direction and is connected to the annular channel and the axial cooling channel of the stator core. The second-stage oil injection ring is connected to the second end of the stator core. It has an axially offset second oil injection hole in the circumferential direction and is connected to the annular channel and the axial cooling channel of the stator core.

2. The stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1, characterized in that: The stator core has several stator slots along its circumference; The stepped oil injection and inclined slot flow-guided co-cooling stator system further includes: several sets of windings, each winding is embedded in a corresponding stator slot, and an insulating layer is provided between them, the thermal conductivity of the insulating layer is greater than a set thermal conductivity threshold. The exposed area at the end of the winding serves as a heat exchange interface, and the cooling oil injected from the first and second oil injection holes is directed toward the heat exchange interface.

3. A stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1 or 2, characterized in that: External cooling oil first enters the radial cooling channels of the stator core; then it is sent from the radial cooling channels to the axial cooling channels and annular channels of the stator core, and guided from the axial cooling channels and annular channels to the first and second stage oil injection rings for axial-tangential composite flow guidance; then it is sprayed onto the windings through the first and second oil injection holes; finally, it is recovered through the drain port on the housing, forming a complete flow guidance-oil injection-oil discharge cooling closed-loop system.

4. The stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1, characterized in that: The first-stage oil injection ring adopts a stepped structure in the circumferential direction, including several first steps arranged in a step-like manner along the circumferential direction of the first-stage oil injection ring. Each first oil injection hole is arranged in layers on the corresponding first step in an axially staggered manner to form a first multi-layer oil injection hole array for realizing multi-stage spray cooling. The second-stage injection ring adopts a stepped structure in the circumferential direction, including several second steps arranged in a stepped manner along the circumferential direction of the second-stage injection ring. Each second injection hole is arranged in layers on the corresponding second step in an axially staggered manner to form a second multi-layer injection hole array for multi-stage spray cooling.

5. A stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1 or 4, characterized in that: The oil jets sprayed from the first and second stage oil injection rings are distributed in a mist, cone, or fan shape, and the oil jets evenly cover the heat-sensitive areas of the winding ends and stator core end faces.

6. A stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1 or 4, characterized in that: The diameter of the first injection hole is 0.6~1.2mm; the diameter of the second injection hole is 0.6~1.2mm.

7. The stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1, characterized in that: The oil injection ring is also equipped with a filter and an anti-backflow stop.

8. The stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1, characterized in that: Each annular channel has a sloping or curved cross-section.

9. The stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1, characterized in that: Each annular groove is inclined at an angle of 3 to 5 degrees relative to the axial direction of the stator core.

10. The stator system for coordinated cooling by stepped oil injection and inclined slot flow as described in claim 1, characterized in that: The stator core adopts a multi-layer lamination structure, and the multi-layer laminations are welded and fixed at the axial cooling channels of the stator core.

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