Stator cooling system and motor including the system

Abstract

The present invention provides a stator cooling system and an electric motor including the system. The stator cooling system includes: a stator with a plurality of coils wound around it; a housing configured to cover at least a portion of the outer surface of the stator and having an oil supply port; and at least one cooling pipe configured to spray oil supplied through the oil supply port onto at least one of the plurality of coils, wherein the at least one cooling pipe is configured to spray oil into at least one connecting path formed between the plurality of coils.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2025-0019424, filed with the Korean Intellectual Property Office on February 14, 2025, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to a stator cooling system and an electric motor including the system. Background Technology

[0004] Environmentally friendly vehicles, such as electric vehicles (EVs), hybrid electric vehicles (HEVs / PHEVs), and fuel cell electric vehicles (FCEVs), are broadly classified as electric vehicles that rely on electric motors for propulsion. These vehicles are equipped with an electric motor as the drive source (e.g., a drive power supply) and an inverter to convert direct current (DC) from a high-voltage power supply into alternating current (AC) to drive and control the motor. In this way, environmentally friendly vehicles utilize the electric motor to generate driving force, and the motor driving these vehicles (i.e., the drive motor) needs to have high efficiency and high output density. It is known that the efficiency of drive motors in recently developed environmentally friendly vehicles is approximately 90%, with a large portion of the remaining losses (such as energy losses) being heat losses. Therefore, a stable thermal management system is crucial to meet the continuous demands for miniaturization, high output, and high efficiency of the motor.

[0005] During motor operation, components such as coils generate a significant amount of heat, making cooling these key components essential. Cooling the internal permanent magnet synchronous motor (IPSM), widely used as a vehicle drive motor, plays a crucial role in protecting motor efficiency and core components (permanent magnets, coils, etc.). When the permanent magnet temperature reaches a certain level (e.g., ℃) or higher, demagnetization may occur, weakening the magnetic force, which significantly negatively impacts motor efficiency.

[0006] Therefore, to prevent the motor system from overheating beyond its permissible temperature range (which could lead to damage to the stator coils or demagnetization of the permanent magnets), effective thermal management and cooling of the motor system are necessary. This requires a suitable thermal management and cooling system to ensure stable operation of the motor within its permissible temperature range. Summary of the Invention

[0007] One aspect of the present invention is to provide a stator cooling system with improved cooling performance and an electric motor including the system.

[0008] Another aspect of the present invention is to provide a stator cooling system that can reduce manufacturing costs and an electric motor including the system.

[0009] According to one aspect of the invention, a stator cooling system includes: a stator with a plurality of coils wound around it; a housing configured to cover at least a portion of the outer surface of the stator and having an oil supply port; and at least one cooling pipe configured to spray oil supplied through the oil supply port onto at least one of the plurality of coils, wherein the at least one cooling pipe is configured to spray oil into at least one communicating path formed between the plurality of coils.

[0010] In the stator cooling system of this embodiment of the invention, the cooling pipes may be formed of plastic material.

[0011] In the stator cooling system of this embodiment of the invention, the cooling pipe can spray oil into the connecting path exposed on the inner peripheral surface of multiple coils. Attached Figure Description

[0012] The above and other aspects, features and advantages of the present invention will be more clearly understood through detailed description and in conjunction with the accompanying drawings, wherein:

[0013] Figure 1 This is a partial cross-sectional view of the stator cooling system according to an embodiment of the present invention;

[0014] Figure 2 This is another partial cross-sectional view of the stator cooling system according to an embodiment of the present invention;

[0015] Figure 3 This is a schematic diagram showing the arrangement of cooling pipes and the stator in a stator cooling system according to an embodiment of the present invention;

[0016] Figure 4 This is a perspective view of the cooling pipes included in the stator cooling system according to an embodiment of the present invention;

[0017] Figure 5 This is a schematic diagram showing the positional relationship between the cooling pipes and the coils disposed in the stator in the stator cooling system according to an embodiment of the present invention;

[0018] Figure 6 This is an axial sectional view of a coil disposed in the stator of a stator cooling system according to an embodiment of the present invention; and

[0019] Figures 7A to 7D This is a schematic diagram illustrating the manufacturing process of a cooling pipe included in a stator cooling system according to an embodiment of the present invention. Detailed Implementation

[0020] While the invention may be modified in various ways and present in many alternative forms, specific embodiments thereof are shown in the accompanying drawings and described in detail below. However, it should be understood that the invention is not intended to be limited to the specific forms disclosed; rather, the invention encompasses all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0021] It should be understood that although terms such as “first” and “second” may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element without departing from the scope of the invention, and similarly, a second element may be referred to as a first element. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0022] Terms such as “unit,” “component,” and “part” can be used to describe various components, but these components should not be limited by these terms. The above terms can refer not only to physically / visually independent components, but also to functional or partial components, even if the corresponding parts are not explicitly defined.

[0023] The terminology used herein to describe embodiments of the invention is not intended to limit the scope of the invention. The articles “a” and “an” are in the singular form because they refer to a single object; however, the use of the singular form herein should not preclude the existence of multiple objects referred to. In other words, unless the context explicitly indicates otherwise, an element referred to in the singular form herein may be one or more. It should also be further understood that when the terms “comprising,” “including,” “having,” and / or “containing” are used herein, the presence of the stated feature, number, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, numbers, steps, operations, elements, components, and / or combinations thereof is not excluded.

[0024] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as understood by one of ordinary skill in the art to which this invention pertains. Such terms, as defined in a common dictionary, shall be interpreted as having the same meaning in the context of the relevant art, and shall not be construed as having an ideal or overly formal meaning unless expressly defined in the application.

[0025] In the following description, the terms "front," "back," "top," "bottom," "upper," and "lower," used to describe directions, are based on the illustrations in the accompanying drawings. When a component, unit, controller, device, element, or apparatus of the present invention is described as having a purpose or performing an operation or function, it should be understood herein as being "configured" to achieve that purpose or perform that operation or function. Each component, unit, controller, device, element, or apparatus may be embodied independently or as part of an apparatus, including a processor and memory (e.g., a non-transitory computer-readable medium).

[0026] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0027] Figure 1 This is a partial cross-sectional view of the stator cooling system according to an embodiment of the present invention. Figure 2 This is another partial cross-sectional view of the stator cooling system according to an embodiment of the present invention, and... Figure 1 The partial sectional views are different.

[0028] Reference Figure 1 and Figure 2 The stator cooling system 10 of this embodiment may include a stator 100, a housing 200 and a cooling pipe 300.

[0029] The stator 100 may be provided with a plurality of annular stator cores stacked axially. The stator 100 may include teeth 110 disposed on the inner circumferential surface of the stator 100. The teeth 110 may be formed by radially inwardly projecting from the inner surface of the stator cores, and the plurality of teeth 110 may be arranged circumferentially (e.g., in a circular direction), forming slots between the plurality of teeth 110. A coil 120 may be inserted into this slot, the coil 120 being inserted into the slot between the teeth 110 and connected to an external power source to generate an electromagnetic field. For example, the coil 120 may be a rectangular conductor. For example, the coil 120 may be a hairpin coil. The plurality of coils 120 may be inserted radially into the slots.

[0030] Coil 120 may be exposed on both sides of stator 100 along the axial direction. For example, when coil 120 is configured as a hairpin coil, the head of coil 120 may be exposed on the outside of one axial end of stator 100, and the legs of coil 120 may be exposed on the outside of the other axial end of stator 100. Cooling pipe 300 can cool coil 120 by spraying oil onto the inner surface of coil 120 exposed on both axial sides of stator 100.

[0031] Multiple coils 120 may be arranged circumferentially. The multiple coils may be arranged such that at least a portion of the coils overlap radially. The coils 120 may form layers connected circumferentially. Multiple layers may be provided. In other words, the multiple coils 120 may form multiple layers L1, L2, and L3 radially. The number of layers formed by the coils 120, for example, the number of layers included in a coil group or the number of coils 120, may vary according to the specifications of the motor.

[0032] A connecting path can be formed in coil 120 or coil group (120a, see...). Figure 5Multiple layers L1, L2, and L3 may form or define the connecting path 120a. The connecting path 120a may be formed by the mechanical shape of multiple coils 120 or coil groups. That is, when multiple coils 120 or coil groups form multiple layers L1, L2, and L3, the connecting path 120a may refer to the space that radially penetrates these layers. More specifically, when multiple coils 120 or coil groups are inserted into the stator 100, the space formed by the radially arranged multiple coils 120 without radial overlap is the connecting path 120a. The connecting path 120a may connect the internal and external spaces of the multiple layers L1, L2, and L3. In other words, the connecting path 120a may pass through the multiple layers L1, L2, and L3. The connecting path 120a may connect the internal and external spaces of the multiple layers L1, L2, and L3 radially. The multiple coils 120 may be arranged in the radial direction of the stator 100. The connecting path 120a may be formed in the radial direction to pass through the multiple coils 120. Multiple connecting paths 120a can be provided in the circumferential and axial directions of the stator 100.

[0033] The housing 200 may be configured to cover at least a portion of the outer surface of the stator 100. The housing 200 may be provided with an oil supply port 210. The oil supply port 210 may be connected to an external oil supply unit. Oil supplied from the oil supply unit may be supplied to the cooling pipe 300 through the oil supply port 210.

[0034] Figure 3 This is a schematic diagram illustrating the arrangement of cooling pipes and the stator in a stator cooling system according to an embodiment of the present invention. Figure 4 This is a perspective view of the cooling pipes included in the stator cooling system according to an embodiment of the present invention. Figure 5 This is a schematic diagram showing the positional relationship between the cooling pipes and coils disposed in the stator of the stator included in the stator cooling system according to an embodiment of the present invention. Figure 6 This is an axial sectional view of a coil disposed in the stator of a stator cooling system according to an embodiment of the present invention.

[0035] Reference Figures 3-6Cooling pipes 300 may be disposed on both axial sides of stator 100. Cooling pipes 300 may be configured such that their outer surfaces face the inner surfaces of the plurality of coils 120 or coil groups. Cooling pipes 300 may spray oil supplied through oil inlets 210 of housing 200 onto the plurality of coils 120 or coil groups of stator 100. For example, cooling pipes 300 may spray oil onto the inner circumferential surfaces of the plurality of coils 120 or coil groups. For example, cooling pipes 300 may spray oil onto at least one of the plurality of connecting paths 120a formed between the plurality of coils 120. Cooling pipes 300 may spray oil onto an opening or a first opening of a connecting path 120a exposed to the inner circumferential surfaces of the plurality of coils 120 or coil groups. Oil flowing into the first opening of connecting path 120a may flow radially outward to another opening or a second opening of connecting path 120a and contact the plurality of radially arranged coils 120. Since the oil flows into the connecting path 120a and contacts the radially arranged multiple coils 120, the cooling effect of the oil on the multiple coils 120 or coil groups can be improved.

[0036] The cooling tube 300 can be made of a plastic material, for example, a high-performance engineering plastic that exhibits excellent mechanical strength and dimensional stability even at high temperatures. By manufacturing the cooling tube 300 using a plastic material, the insulation distance d1 between the cooling tube 300 and the plurality of coils 120 or coil groups can be minimized or ignored. Here, the insulation distance d1 refers to the distance between the radially outer surface of the cooling tube 300 and the radially inner circumferential surface of the plurality of coils 120 or coil groups. For example, this insulation distance d1 can be set to less than 14.5 mm, or more than 3.5 mm and less than 7.5 mm.

[0037] By using plastic materials to manufacture the cooling pipe 300, the cooling pipe 300 can be arranged as close as possible to the inner circumferential surface of the multiple coils 120 or coil groups. By minimizing the gap between the cooling pipe 300 and the multiple coils 120 or coil groups, the reliability of the injection position and injection speed can be improved, thereby improving the cooling performance of the multiple coils 120 or coil groups.

[0038] The cooling pipe 300 may include a first cooling pipe 300a disposed at one axial end (e.g., the first end) of the stator 100, and a second cooling pipe 300b disposed at the other axial end (e.g., the second end) of the stator 100. The first cooling pipe 300a and the second cooling pipe 300b may be configured to have the same structure. The first cooling pipe 300a may spray oil onto a plurality of coils 120 or coil groups exposed outside the axial end (e.g., the first end) of the stator 100, and the second cooling pipe 300b may spray oil onto the plurality of coils 120 or coil groups exposed outside the other axial end (e.g., the second end) of the stator 100. The first cooling pipe 300a and the second cooling pipe 300b may respectively spray oil onto the inner circumferential surfaces of the plurality of coils 120 or coil groups. For example, the first cooling pipe 300a and the second cooling pipe 300b may spray oil onto a connecting path 120a exposed on the inner circumferential surfaces of the plurality of coils 120 or coil groups. Oil sprayed into the connecting path 120a can pass radially through multiple coils 120 or coil groups to cool the multiple coils 120 or coil groups. In other words, oil can pass radially through multiple layers L1, L2 and L3 forming multiple coils 120 or coil groups and contact the multiple coils 120 or coil groups, thereby cooling the multiple coils 120 or coil groups.

[0039] The cooling pipe 300 may be annular. The cooling pipe 300 may have oil injection holes 320c for oil injection. Multiple oil injection holes 320c may be spaced apart from each other at predetermined intervals in the circumferential direction of the cooling pipe 300. The oil injection holes 320c may be configured to extend radially to connect the internal and external spaces of the cooling pipe 300. The oil injection holes 320c may be inclined, for example, they may be inclined axially inward. An insulator for insulation may be provided near the legs of the multiple coils 120 or coil groups, and this insulator may be located at the axially outer end of the legs. The portions of the multiple coils 120 or coil groups where the insulator is provided do not form a connecting path with the insulator. Therefore, the oil injection holes 320c may be inclined axially inward so that oil injected from the cooling pipe 300 can be supplied to the connecting path 120a. For example, the injection hole 320c may be inclined toward the innermost axial connecting path 120a or the second innermost axial connecting path 120a formed in a plurality of coils 120 or coil groups.

[0040] Figures 7A to 7D This is a schematic diagram illustrating the manufacturing process of a cooling pipe included in a stator cooling system according to an embodiment of the present invention.

[0041] Reference Figures 7A to 7DThe cooling pipe 300 may include, for example, a first housing 310 and a second housing 320. The first housing 310 and the second housing 320 may each be annular with an axially open side. The first housing 310 and the second housing 320 may each have a semi-circular cross-section in the circumferential direction. The open surfaces of the first housing 310 and the second housing 320 may engage with each other. A connecting groove 310a may be provided on the open surface of the first housing 310. In other words, the connecting groove 310a may be provided on a surface of the first housing 310 facing the second housing. The connecting groove 310a may be continuously arranged circumferentially. The connecting groove 310a may be provided on both radially inner and outer sides. The open surface of the second housing 320 may be provided with a blocking wall 320a, which can be inserted into the connecting groove 310a. The blocking wall 320a may be continuously arranged circumferentially. The blocking wall 320a may be provided on both radially inner and outer sides. When the blocking wall 320a is inserted into the connecting groove 310a, one surface of the first housing 310 and one surface of the second housing 320 can come into contact with each other, and an oil flow path can be formed between the first housing 310 and the second housing 320. Furthermore, when the blocking wall 320a is inserted into the connecting groove 310a, injection grooves 330 are formed circumferentially on the radially inner and outer sides of the first housing 310 and the second housing 320. The radially inner and outer sides of the first housing 310 and the second housing 320 can be the radially inner and outer sides relative to a plurality of coils 120 or coil groups, and the injection grooves 330 can be continuously arranged circumferentially. Injection molding material 330a, which bonds the first housing 310 and the second housing 320, can be provided within the injection groove 330. The injection molding material 330a can be, for example, a weld bead. The first housing 310 and the second housing 320 can be combined to form an annular channel through which oil flows.

[0042] The first housing 310 may include an inlet 311 that can be connected to the housing 200 to receive oil. For example, the inlet 311 may be connected to an oil supply port 210 to receive oil from the oil supply port 210.

[0043] The second housing 320 may include oil injection holes 320c, and multiple oil injection holes 320c may be arranged circumferentially. The oil injection holes 320c may be formed by penetrating the second housing 320 radially toward the coil 120, in which case the oil injection holes 320c may be formed to be inclined at a predetermined angle α toward the axially inward side. The oil injection holes 320c may be formed to open toward one side of the communication path 120a exposed on the inner circumferential surface of the multiple coils 120 or coil group, and the oil injection holes 320c may be configured such that the centerline c1 faces the communication path 120a.

[0044] Cooling pipe 300 can be injection molded. For example, sliding injection molding (DSI) can be used as the injection molding process for cooling pipe 300. Cooling pipe 300 can be manufactured by single and double injection molding processes. For example, first housing 310 and second housing 320 can be injection molded in one step (see...). Figure 7A When the first housing 310 and the second housing 320 are injection molded, the mold into which the first housing 310 is injected is slidably movable. The mold is slidably movable so that the center of the first housing 310 is aligned with the center of the second housing 320 (see...). Figure 7B When the centers of the first housing 310 and the second housing 320 are aligned, the mold for injecting into the first housing 310 can engage with the mold for injecting into the second housing 320. With the molds engaged, the opening surfaces of the first housing 310 and the second housing 320 can come into contact with each other (see...). Figure 7C The opening surfaces of the first housing 310 and the second housing 320 can come into contact through the sliding movement of the mold into the first housing 310. The blocking wall 320a of the second housing 320 can be inserted into the mating groove 310a of the first housing 310. Injection grooves 330 are formed circumferentially on the radially inner and outer sides of the first housing 310 and the second housing 320. A secondary injection molding process can be performed on the injection grooves 330. For example, secondary injection molding material 330a can be injected into the injection grooves 330 (see...). Figure 7D The secondary injection molding material 330a can be, for example, a weld bead. The secondary injection molding material 330a can bond the first housing 310 to the second housing 320. During the secondary injection molding process, the barrier wall 320a can prevent the injection molding material 330a from flowing into the first housing 310 and the second housing 320.

[0045] The motor 1 may include a stator cooling system 10. Furthermore, the motor 1 may include a rotor. The rotor is a structure rotatable within the stator 100 and may include a cylindrical rotor core and magnets disposed within the rotor core.

[0046] As previously described, the stator cooling system 10 according to an embodiment of the present invention includes cooling pipes 300 located on both axial sides of the stator 100, and sprays oil onto the inner circumferential surfaces of a plurality of coils 120 or coil groups, thereby effectively cooling the stator 100.

[0047] At this time, by using plastic material to form the cooling pipe 300, the cooling pipe 300 can be arranged as close as possible to multiple coils 120 or coil groups to improve the oil injection reliability and cooling efficiency of the cooling pipe 300.

[0048] Furthermore, by using the DSI method to manufacture the cooling pipe 300, not only can manufacturing costs be reduced, but the appearance quality of the product can also be improved.

[0049] The stator cooling system and the motor including the system according to embodiments of the present invention can have improved cooling performance.

[0050] Furthermore, the stator cooling system and the motor including the system according to embodiments of the present invention can reduce manufacturing costs.

[0051] Although exemplary embodiments have been described and illustrated above, those skilled in the art will understand that modifications and variations may be made without departing from the scope of the invention as defined by the appended claims.

Claims

1. A stator cooling system, comprising: The stator has multiple coils wound around it; The housing is configured to cover at least a portion of the outer surface of the stator and has an oil supply port; as well as At least one cooling pipe is configured to spray oil supplied through the oil inlet onto at least one of the plurality of coils. The at least one cooling pipe is configured to spray oil into at least one connecting path formed between the plurality of coils.

2. The stator cooling system according to claim 1, wherein: The plurality of coils are arranged radially along the stator; The at least one connecting path is formed on the outer side of at least one of the two ends of the stator in the axial direction; The at least one connecting path is formed radially to pass through the plurality of coils.

3. The stator cooling system according to claim 1, wherein, The at least one connection path includes multiple connection paths along the circumferential and axial directions of the stator.

4. The stator cooling system according to claim 1, wherein, The at least one cooling pipe is made of plastic material.

5. The stator cooling system according to claim 4, wherein, The radial distance between the radial outer side of the at least one cooling pipe and the inner circumferential surface of the plurality of coils is set to be more than 3.5 mm and less than 7.5 mm.

6. The stator cooling system according to claim 1, wherein, The at least one cooling pipe includes: A first cooling pipe is disposed at the first axial end of the stator; and The second cooling pipe is located at the second axial end of the stator.

7. The stator cooling system according to claim 6, wherein, The first cooling pipe is configured to spray oil onto the inner circumferential surface of the plurality of coils exposed outside the first end of the stator along the axial direction, and the second cooling pipe is configured to spray oil onto the inner circumferential surface of the plurality of coils exposed outside the second end of the stator along the axial direction.

8. The stator cooling system according to claim 7, wherein, The first cooling pipe and the second cooling pipe are configured to spray oil onto at least one connecting path exposed on the inner peripheral surface of the plurality of coils.

9. The stator cooling system according to claim 8, wherein, Oil injected from the first and second cooling pipes passes radially through the plurality of coils and cools the plurality of coils.

10. The stator cooling system according to claim 1, wherein, The at least one cooling pipe is configured as an annular structure and has a plurality of oil injection holes arranged circumferentially.

11. The stator cooling system according to claim 10, wherein, The outer peripheral surface of at least one cooling tube is configured as the inner peripheral surface facing the plurality of coils.

12. The stator cooling system according to claim 11, wherein, The at least one cooling pipe includes: A first outer casing, having an inlet connected to the casing and configured to receive oil; and The second housing is connected to the first housing and together with the first housing forms the path through which the oil flows, and has the plurality of oil injection holes.

13. The stator cooling system according to claim 12, wherein, The plurality of oil injection holes are formed to penetrate the second housing radially toward the plurality of coils.

14. The stator cooling system according to claim 13, wherein, The plurality of injection holes are formed to be inclined inward along the axial direction.

15. The stator cooling system according to claim 12, wherein, A circumferential groove is provided on one surface of the first housing facing the second housing, and a blocking wall configured to be inserted into the circumferential groove is provided on one surface of the second housing facing the first housing.

16. The stator cooling system according to claim 15, wherein, Based on the insertion of the blocking wall into the connecting groove, injection grooves are formed circumferentially on the radially inner and radially outer sides of the first and second outer shells.

17. The stator cooling system according to claim 16, wherein, The injection molding tank contains injection molding material that allows the first outer shell and the second outer shell to be joined together.

18. An electric motor comprising the stator cooling system of claim 1.

19. A stator cooling system, comprising: The stator has multiple coils wound around it; Housing, including the oil supply port; as well as The cooling pipe is configured to spray oil into the connecting path formed between the plurality of coils.

20. A method for manufacturing a cooling pipe, comprising the following steps: The blocking wall of the second outer shell is inserted into the joint groove of the first outer shell to form an injection groove; as well as Injection molding material into the injection tank to bond the first shell to the second shell.

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