Liquid injection type motor and winding reinforcement cooling method thereof

Abstract

The application discloses a liquid injection type motor and a winding reinforced cooling method thereof, and belongs to the technical field of liquid injection type motors. In order to solve the problem that the heat transfer and heat conduction coefficient of the winding of the existing motor is not ideal and additional cooling equipment needs to be added, the heat generated by the built-in winding is transferred to the winding liquid cavity in the liquid insulation wall through the liquid insulation wall and the pouring glue, the liquid in the cavity generates thermal convection after being heated, the liquid is convected to the liquid in the shell liquid cavity through the liquid channel, the liquid and the shell convect and exchange heat, and finally the heat of the built-in winding is transferred to the shell. The contact type heat transfer mode is reserved between the pouring glue, the built-in winding, the slot insulation, the stator core and the shell. Meanwhile, the cavity exists between the stator assembly and the shell liquid cavity, the natural air convection mode is realized, and finally the cooling liquid is injected through the liquid injection hole. The liquid channel hole arranged on the shell liquid cavity is communicated with the winding liquid cavity cavity in the liquid insulation wall, and the cooling liquid realizes cooling and strengthening.

Description

Technical Field

[0001] This invention relates to the field of liquid-filled motor technology, and in particular to a liquid-filled motor and a method for enhancing the cooling of its windings. Background Technology

[0002] In fields such as new energy vehicles, industrial servo motors, rail transit, aviation electric drives, and high-power wind power, permanent magnet synchronous motors have been widely adopted due to their advantages of high efficiency, high torque density, and lightweight design. As the industry continues to pursue miniaturization, high power density, short-term strong overload, and long lifespan, motor losses continue to increase. For motors, the temperature rise safety of the windings is directly related to the reliability of motor operation. With various industries demanding higher and higher motor power density, reducing the temperature of the windings has become an urgent task.

[0003] For motors with natural convection cooling, the traditional method of cooling motor windings involves heat transfer between the windings, slot insulation, stator core, and housing, with heat dissipation achieved through natural convection of air between the windings, housing, and external environment. The disadvantage is that the heat transfer path from the windings to the housing is limited, especially since the thermal conductivity of the slot insulation is not ideal, which is the biggest bottleneck for heat transfer from the windings. The air heat transfer coefficient is extremely low, making it unsuitable for high power density motors. Existing methods to improve the cooling capacity of motor windings mostly focus on changing the natural convection cooling method to forced air cooling, forced water cooling, or forced oil cooling. This requires the addition of additional cooling equipment, reducing the overall space utilization of the motor system.

[0004] To address the aforementioned problems, a liquid-filled motor and its winding enhanced cooling method are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a liquid-filled motor and a method for enhancing the cooling of its windings. This solves the problem that in the prior art, the transmission path from the motor windings to the housing is limited, especially the thermal conductivity of the slot insulation is not ideal. Most methods to improve the cooling capacity of the motor windings focus on changing the natural air convection cooling method to forced air cooling, forced water cooling, or forced oil cooling. This requires the addition of additional cooling equipment and reduces the overall space utilization of the motor system.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a liquid-filled motor, comprising a housing, end cap assemblies, and a stator assembly. End cap assemblies are fixedly disposed on both sides of the housing. The stator assembly is filled inside the housing. A liquid cavity is formed inside the housing for storing liquid. A liquid injection hole is formed on the housing. The stator assembly includes a stator core, slot insulation, internal windings, a liquid insulating wall, and potting compound. A winding liquid cavity is formed inside the liquid insulating wall. The outer surface of the stator core is interference-fitted with the inner surface of the housing. A liquid channel hole connected to the liquid insulating wall is formed on the housing. The slot insulation is disposed close to the teeth of the stator core. The internal windings are tightly wound on the outside of the slot insulation. The two inclined surfaces of the liquid insulating wall are close to the internal windings. The potting compound is applied to the side ends of the stator core to fill internal gaps. The outer surface of the potting compound is flush with the outer surface of the stator core.

[0007] Furthermore, a liquid injection plug is installed on the liquid injection hole on the outside of the housing.

[0008] Furthermore, the stator assembly is internally provided with a rotor core.

[0009] Furthermore, the liquid channel holes are arranged in a circular array with multiple sets.

[0010] Furthermore, the end cap assembly includes a first side end cap and a second side end cap disposed on both sides of the stator assembly.

[0011] Furthermore, the liquid channel holes are located on both sides of the winding liquid chamber.

[0012] Furthermore, the rotor core has multiple sets of magnets arranged in a circular array inside.

[0013] Furthermore, a rotating shaft is fixedly disposed at the center of the rotor core, and rotor end plate assemblies are fixedly disposed on both sides of the rotor core. The rotor end plate assembly includes a first rotor end plate and a second rotor end plate disposed on both sides.

[0014] Furthermore, a bearing is connected between the end cap assembly and the rotating shaft, and two sets of bearings are provided.

[0015] Another technical solution proposed by this invention: Provides a liquid-filled motor and a method for enhancing the cooling of its windings, comprising the following methods: S1: Heat transfer method: potting compound, built-in winding, slot insulation, and contact heat transfer between stator core and housing; S2: Natural air convection: There is a cavity between the stator assembly and the liquid cavity of the shell to achieve natural air convection; S3: Coolant convection method: Coolant is injected through the injection hole, and the liquid channel hole on the shell liquid cavity is connected to the winding liquid cavity cavity inside the liquid insulating wall, thereby enhancing the cooling effect of the coolant.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention provides a liquid-filled motor in which the inclined surfaces on both sides of the liquid insulating wall are closely attached to the built-in winding to ensure heat transfer between them. The winding liquid cavity is used to store liquid and realize heat exchange between the liquid and the liquid insulating wall. One side of the liquid insulating wall is connected to a liquid channel hole for connection with the housing. When the temperature of the built-in winding rises due to heat generation, the heat emitted by the built-in winding is transferred to the winding liquid cavity inside the liquid insulating wall through the liquid insulating wall and potting compound. After being heated, the liquid in the cavity undergoes thermal convection and flows through the liquid channel to the liquid in the housing liquid cavity. The liquid and the housing exchange heat through convection, and finally the heat of the built-in winding is transferred to the housing. Compared with the traditional cooling method of motor windings, this invention increases the heat transfer path from the built-in winding to the housing without adding an additional external cooling device for the motor. This solves the problem that most existing methods for improving the cooling capacity of motors focus on changing the natural air convection cooling method to forced air cooling, forced water cooling, or forced oil cooling, which requires additional cooling equipment and reduces the overall space utilization of the motor system.

[0017] 2. The present invention provides a method for enhancing the cooling of the windings of a liquid-filled motor. This method maintains contact-type heat transfer between the potting compound, the built-in windings, the slot insulation, the stator core, and the housing. Simultaneously, a cavity exists between the stator assembly and the liquid cavity of the housing to achieve natural air convection. Finally, coolant is injected through the injection hole. The liquid channel hole on the liquid cavity of the housing is connected to the cavity of the winding liquid cavity inside the liquid insulation wall, thereby enhancing the cooling effect of the coolant. This solves the problem of limited heat transfer path from the motor windings to the housing, especially the problem of unsatisfactory thermal conductivity of the slot insulation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the housing of the present invention; Figure 3 This is a schematic diagram of the packaging structure of the stator assembly of the present invention; Figure 4 This is a schematic diagram of the internal structure of the stator assembly of the present invention; Figure 5 This is a schematic diagram of the liquid insulating wall structure of the present invention; Figure 6 This is a schematic cross-sectional view of the motor structure of the present invention. Figure 1 ; Figure 7 For the present invention Figure 6A schematic diagram of the structure at point A; Figure 8 This is a schematic cross-sectional view of the motor structure of the present invention. Figure 2 ; Figure 9 For the present invention Figure 8 A schematic diagram of the structure at point B; Figure 10 This is a schematic diagram of the winding cooling method of the present invention.

[0019] In the diagram: 1. Housing; 11. Housing liquid chamber; 12. Liquid injection hole; 121. Liquid injection plug; 13. Liquid channel hole; 2. End cover assembly; 21. First side end cover; 22. Second side end cover; 3. Stator assembly; 31. Stator core; 32. Slot insulation; 33. Internal winding; 34. Liquid insulation wall; 341. Winding liquid chamber; 35. Encapsulant; 4. Rotor core; 5. Magnet; 6. Shaft; 7. Rotor end plate assembly; 71. First rotor end plate; 72. Second rotor end plate; 8. Bearing. Detailed Implementation

[0020] 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. 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.

[0021] In order to solve existing technical problems, such as Figures 1-9 As shown, the following preferred technical solutions are provided: A liquid-filled motor includes a housing 1, end cap assemblies 2, and a stator assembly 3. End cap assemblies 2 are fixedly mounted on both sides of the housing 1. The stator assembly 3 is filled inside the housing 1. A liquid cavity 11 is formed inside the housing 1 for storing liquid. A liquid injection hole 12 is formed on the housing 1. The stator assembly 3 includes a stator core 31, slot insulation 32, internal windings 33, a liquid insulating wall 34, and potting compound 35. A winding liquid cavity is formed inside the liquid insulating wall 34. 341, the outer circular surface of the stator core 31 is interference-fitted with the inner circular surface of the housing 1. The housing 1 has a liquid channel hole 13 connected to the liquid insulating wall 34. The slot insulation 32 is set close to the teeth of the stator core 31. The internal winding 33 is tightly wound on the outside of the slot insulation 32. The two inclined surfaces of the liquid insulating wall 34 are close to the internal winding 33. The potting compound 35 is potted on the side end of the stator core 31 to fill the internal gaps. The outer surface of the potting compound 35 is flush with the outer circular surface of the stator core 31.

[0022] Specifically, this device is an internal rotor type 12-slot 8-pole permanent magnet synchronous motor, which can be extended to internal rotor motors with other pole-slot combinations or other excitation methods. The housing liquid chamber 11 stores liquid to achieve heat exchange with the housing 1. The liquid injection hole 12 injects liquid into the housing liquid chamber 11. This liquid can be pure water, alcohol, or a mixture of alcohol and water. The two inclined surfaces of the liquid insulating wall 34 are in close contact with the built-in winding 33 to ensure heat transfer between the two. The potting compound 35 is potted on the entire side of the stator core 31, filling all the gaps in the slots of the stator assembly 3. The outer surface of the potting compound 35 is flush with the outer circular surface of the stator core 31 to ensure adhesion to the inner circular surface of the housing 1. This section is completed by connecting the stator assembly 3 to the housing 1 and then potting. The winding liquid chamber 341 is used to store liquid to achieve heat exchange between the liquid and the liquid insulating wall 34. One side of the liquid insulating wall 34 is connected to the liquid channel hole 13 for connection with the housing 1. The connection should be liquid-sealed. The liquid insulation wall 34 should be made of insulating material with good thermal conductivity, which should not be less than 1W / mK. The thickness of the two inclined surfaces of the liquid insulation wall 34 should be as small as possible, and the thickness should not be greater than 0.5mm. When the temperature of the built-in winding 33 rises due to heat generation, the heat emitted by the built-in winding 33 is transferred to the winding liquid cavity 341 inside the liquid insulation wall 34 through the liquid insulation wall 34 and the potting compound 35. After the liquid in the cavity is heated, thermal convection occurs. It flows through the liquid channel to the liquid in the housing liquid cavity 11. The liquid and the housing 1 exchange heat through convection. Finally, the heat of the built-in winding 33 is transferred to the housing 1. Compared with the traditional cooling method of motor winding, this method increases the heat transfer path from the built-in winding 33 to the housing 1, and does not require an additional external cooling device for the motor. A liquid injection plug 121 is installed on the liquid injection hole 12 outside the housing 1. The sealing of the liquid injection plug 121 ensures that the liquid is sealed inside the housing 1.

[0023] The stator assembly 3 has a rotor core 4 inside. When the motor is working, the stator assembly 3 is supplied with alternating current and generates a rotating magnetic field. The rotor core 4 is assembled inside the stator assembly 3. The high magnetic permeability of the rotor core 4 can form a closed magnetic circuit, reduce magnetic resistance, reduce excitation loss, and improve motor torque and efficiency. The liquid channel holes 13 are arranged in a circular array with multiple sets. The multiple sets of liquid channel holes 13 increase the liquid flow area and improve heat exchange efficiency.

[0024] The end cap assembly 2 includes a first side end cap 21 and a second side end cap 22 disposed on both sides of the stator assembly 3. The first side end cap 21 and the second side end cap 22 are disposed on both sides of the housing 1 to encapsulate the housing 1. Liquid channel holes 13 are disposed on both sides of the winding liquid chamber 341. Each winding liquid chamber 341 is provided with two sets of liquid channel holes 13 to realize dual-sided thermal management and multi-channel flow.

[0025] The rotor core 4 has multiple sets of magnets 5 arranged in a circular array inside. The multiple sets of magnets 5 provide a constant excitation magnetic field. The rotor core 4 itself has a permanent magnetic field. The two magnetic fields of the stator assembly 3 and the magnets 5 are coupled and pulled to each other, forming a continuous electromagnetic torque that drives the rotor core 4 to rotate.

[0026] A rotating shaft 6 is fixedly installed at the center of the rotor core 4, and rotor end plate assemblies 7 are fixedly installed on both sides of the rotor core 4. The rotor end plate assembly 7 includes a first rotor end plate 71 and a second rotor end plate 72 arranged on both sides. The first rotor end plate 71 and the second rotor end plate 72 are fixed on both sides to realize the enclosure of the rotor core 4, and the rotating shaft 6 is set at the center to rotate.

[0027] A bearing 8 is connected between the end cap assembly 2 and the rotating shaft 6. There are two sets of bearings 8, which realize the rotational connection between the end cap assembly 2 and the rotating shaft 6 and reduce the rotational friction.

[0028] To further illustrate the above embodiments, the present invention also provides an embodiment, a method for enhancing the cooling of the windings of a liquid-filled motor, comprising the following steps: Method 1: Heat transfer method: Contact heat transfer is maintained between potting compound 35, internal winding 33, slot insulation 32, stator core 31 and housing 1; Method 2: Natural air convection: There is a cavity between the stator assembly 3 and the liquid cavity 11 of the shell, which enables natural air convection; Method 3: Coolant convection method: Coolant is injected into the injection hole 12, and the liquid channel hole 13 opened on the shell liquid cavity 11 is connected to the winding liquid cavity 341 inside the liquid insulating wall 34, so that the coolant can achieve enhanced cooling.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0030] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A liquid-filled motor, comprising a housing (1), an end cap assembly (2), and a stator assembly (3), characterized in that: The housing (1) is fixedly provided with end cap assemblies (2) on both sides, and the housing (1) is filled with stator assemblies (3). The housing (1) has a liquid cavity (11) inside, which is used to store liquid. The housing (1) has an injection hole (12). The stator assembly (3) includes a stator core (31), slot insulation (32), internal windings (33), a liquid insulation wall (34), and potting compound (35). The liquid insulation wall (34) has a winding liquid cavity (341) inside. The outer surface of the stator core (31) is interference-fitted with the inner surface of the housing (1). The housing (1) is provided with a liquid channel hole (13) connected to the liquid insulating wall (34). The slot insulation (32) is set close to the teeth of the stator core (31). The built-in winding (33) is tightly wound on the outside of the slot insulation (32). The two inclined surfaces of the liquid insulating wall (34) are close to the built-in winding (33). The potting compound (35) is potted on the side end of the stator core (31) to fill the internal gaps. The outer surface of the potting compound (35) is flush with the outer circular surface of the stator core (31).

2. The liquid-filled motor as described in claim 1, characterized in that: A liquid injection plug (121) is installed on the liquid injection hole (12) outside the housing (1).

3. A liquid-filled motor as described in claim 2, characterized in that: The stator assembly (3) is provided with a rotor core (4) inside.

4. A liquid-filled motor as described in claim 3, characterized in that: The liquid channel holes (13) are arranged in a circular array with multiple sets.

5. A liquid-filled motor as described in claim 4, characterized in that: The end cap assembly (2) includes a first side end cap (21) and a second side end cap (22) disposed on both sides of the stator assembly (3).

6. A liquid-filled motor as described in claim 5, characterized in that: The liquid channel holes (13) are located on both sides of the winding liquid cavity (341).

7. A liquid-filled motor as described in claim 6, characterized in that: The rotor core (4) has multiple sets of magnets (5) arranged in a circular array inside.

8. A liquid-filled motor as described in claim 7, characterized in that: The rotor core (4) is fixedly provided with a rotating shaft (6) at its center, and rotor end plate assemblies (7) are fixedly provided on both sides of the rotor core (4). The rotor end plate assembly (7) includes a first rotor end plate (71) and a second rotor end plate (72) provided on both sides.

9. A liquid-filled motor as described in claim 8, characterized in that: A bearing (8) is connected between the end cap assembly (2) and the rotating shaft (6), and two sets of the bearing (8) are provided.

10. A method for enhancing the cooling of the windings of a liquid-filled motor as described in claim 9, characterized in that: Including the following methods: S1: Heat transfer method: The contact heat transfer method is maintained between potting compound (35), built-in winding (33), slot insulation (32), stator core (31) and housing (1); S2: Natural air convection: There is a cavity between the stator assembly (3) and the shell liquid cavity (11) to achieve natural air convection; S3: Coolant convection method: Coolant is injected through the injection hole (12), and the liquid channel hole (13) on the shell liquid cavity (11) is connected to the winding liquid cavity (341) inside the liquid insulating wall (34), so that the coolant achieves enhanced cooling.

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