A cooling structure, electric machine and electric device

Abstract

The application discloses a cooling structure, a motor and an electric device, and the structure comprises a plurality of cooling grooves which are axially arranged on the inner wall of a stator slot of a stator core, and the opening of the cooling groove is closed by a slot insulation to form a cooling liquid flow channel. The application arranges the cooling grooves on the inner wall of the stator slot, and creatively uses the slot insulation as the closing surface of the cooling groove, so that the cooling pipe does not need to be additionally inserted into the stator slot, the effective space of the winding is hardly occupied, the stator slot fullness is ensured, the heat of the winding is conducted to the stator core and the cooling liquid through the slot insulation, the heat of the stator core is directly conducted to the cooling liquid, the heat conduction path is short, the thermal resistance is extremely small, the heat of the winding and the stator core can be efficiently taken away, and the winding temperature rise is greatly reduced.

Description

Technical Field

[0001] This invention relates to a cooling structure, a motor, and an electric device, belonging to the technical field of motor cooling structure. Background Technology

[0002] As electric motors develop towards higher power density and miniaturization, the heat generation problem of stator windings is becoming increasingly prominent. Traditional water-cooling of the casing or oil-spraying at the ends results in a significant thermal resistance and limited heat dissipation efficiency due to the thick iron core or insulation layer separating the cooling medium from the heat source of the windings. Some existing technologies attempt to embed cooling pipes within the stator slots, but these pipes occupy effective space within the slots, reducing slot fill factor and complicating assembly processes. Another approach involves creating axial oil channels in the yoke of the iron core, but these channels are far from the main heat-generating areas of the windings, resulting in insufficient direct cooling. Therefore, achieving efficient and direct cooling of the windings and stator core by coolant while minimizing the occupation of effective stator slot space has become a pressing problem in this field. Summary of the Invention

[0003] The present invention provides a cooling structure, a motor, and an electric device that solves the problems disclosed in the background art.

[0004] According to one aspect of this application, a cooling structure is provided, including a plurality of cooling grooves formed along the axial direction of the stator core on the inner wall of the stator slot, wherein the opening of the cooling grooves is closed by slot insulation to form a coolant flow channel; wherein the slot insulation is slot insulation disposed in the stator slot for accommodating the winding.

[0005] Furthermore, the front and rear ends of the stator core are respectively provided with a liquid inlet distribution chamber and a liquid outlet manifold chamber. The liquid inlet distribution chamber and the liquid outlet manifold chamber are respectively connected to the inlet and outlet of the coolant flow channel. The liquid inlet of the liquid inlet distribution chamber extends out of the front end cover of the motor where the stator core is located, and the liquid outlet of the liquid outlet manifold chamber extends out of the rear end cover of the motor where the stator core is located.

[0006] Furthermore, both the liquid inlet distribution cavity and the liquid outlet manifold cavity include a first groove that is inverted on the end face of the stator core yoke and a second groove that is inverted on the end face of the stator teeth. The first groove is an annular groove, and the first groove and the second groove are connected.

[0007] Furthermore, the cooling groove is disposed on the bottom inner wall and at least one side inner wall of the stator groove; the first groove is connected to the coolant flow channel corresponding to the bottom inner wall, and the second groove is connected to the coolant flow channel corresponding to the side inner wall.

[0008] Furthermore, all cooling slots are parallel and independent of each other, and the cross-section of the cooling slots can be any one of rectangle, trapezoid, triangle and semicircle.

[0009] Furthermore, a sealing layer is provided between the groove insulation and the opening edge of the cooling groove to achieve an adhesive seal; or, the groove insulation is provided with a protrusion adapted to the opening of the cooling groove, the protrusion being interference-fitted into the opening of the cooling groove.

[0010] Furthermore, the slot insulation is a multi-layer composite insulating sheet, comprising at least an insulating reinforcement layer and a liquid-resistant layer that wraps around the insulating reinforcement layer.

[0011] According to another aspect of this application, an electric motor is provided, including the cooling structure described above.

[0012] According to another aspect of this application, an electric device is provided, including the aforementioned motor.

[0013] The beneficial effects achieved by this invention are as follows: This invention opens cooling grooves on the inner wall of the stator slots and creatively uses the slot insulation as the sealing surface of the cooling grooves. There is no need to insert additional cooling pipes in the stator slots, and it hardly occupies the effective space of the windings, ensuring the stator slot fill factor. Furthermore, the heat of the windings is conducted to the stator core and coolant through the slot insulation, and the heat of the stator core is directly conducted to the coolant. The heat conduction path is short and the thermal resistance is extremely small, which can efficiently remove the heat of the windings and stator cores and significantly reduce the temperature rise of the windings. Attached Figure Description

[0014] Figure 1 Exploded view of the motor structure using a cooling system; Figure 2 An enlarged view of a single stator slot; Figure 3 An axial sectional view of an electric motor using a cooling structure; Figure 4 This is a schematic diagram of the liquid inlet distribution chamber; Figure 5 This is a schematic diagram of the liquid outlet manifold.

[0015] In the diagram, 1-front end cover; 2-liquid inlet distribution chamber; 21-liquid inlet; 3-winding; 4-slot insulation; 5-stator core; 51-cooling tank; 52-slot side wall; 53-slot bottom wall; 6-permanent magnet; 7-rotor core; 8-liquid outlet manifold; 81-liquid outlet; 9-rear end cover; 10-machine casing. Detailed Implementation

[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0017] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application.

[0018] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0019] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0020] 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 have different values.

[0021] It should be noted that similar symbols and letters in the accompanying drawings represent similar items; therefore, once an item is defined in one accompanying drawing, it does not need to be discussed further in subsequent accompanying drawings.

[0022] Furthermore, in the description of the embodiments of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features.

[0023] To address the cooling issues of the motor windings and stator core, embodiments of this application provide a cooling structure integrated within the motor, as detailed below. Figure 1 and Figure 2 The structure mainly includes several cooling grooves 51 opened along the axial direction of the stator core 5 on the groove sidewall 52 and groove bottomwall 53 of the stator groove. The opening of the cooling groove 51 is closed by the groove insulation 4 to form a coolant flow channel. The groove insulation 4 is a groove insulation 4 set in the stator groove to accommodate the winding 3.

[0024] It should be noted that the stator core 5 is generally formed by stacking multiple stator laminations. Therefore, the cooling groove 51 can be created in two ways. The first method is to punch notches on the groove edge of each stator lamination. After the stator laminations are stacked, the notches are aligned to form the cooling groove 51. The second method is to first stack the stator core 5 into shape, and then form the cooling groove 51 on the inner wall of the stator groove by drawing. Both methods are simple in process and low in manufacturing cost. However, in practical applications, the first method is generally used. The first method can treat the stator laminations as a standard part for stamping, avoiding the subsequent drawing process, which can improve the efficiency of motor assembly.

[0025] It should be noted that, in order to enhance the cooling effect, in some embodiments, the cooling groove 51 is provided on the bottom inner wall of the stator slot and at least one side inner wall. In order to achieve the strongest cooling, the cooling groove 51 is generally provided on both side inner walls.

[0026] The number of cooling slots 51 is generally determined based on the actual situation. If there is sufficient space and a large amount of heat is generated, more cooling slots 51 can be added; conversely, fewer cooling slots 51 can be added. To ensure uniform heat dissipation, all cooling slots 51 are parallel and independent of each other. The cross-section of each cooling slot 51 can be any one of rectangular, trapezoidal, triangular, or semi-circular. Figure 2 For example, seven rectangular cooling grooves 51 are opened on the bottom inner wall of the stator slot, and eighteen rectangular cooling grooves 51 are opened on the inner wall of each side of the stator slot. The spacing between adjacent cooling grooves 51 is consistent. This dense arrangement facilitates the fastest cooling.

[0027] It should be noted that the slot insulation 4 is an existing structure in the electrode. In order to isolate the coolant, a multi-layer composite insulating sheet can be used, which includes at least an insulating reinforcement layer and a liquid-resistant layer that wraps the insulating reinforcement layer. For example, a composite sheet of an outer polyimide film and an inner aramid paper has good liquid resistance, insulation strength and thermal conductivity.

[0028] The slot insulation 4 is U-shaped, with its outer surface tightly against the inner wall of the stator slot. A thermally conductive sealant layer can be applied between the slot insulation 4 and the opening edge of the cooling slot 51 to achieve an adhesive seal. Alternatively, a protrusion adapted to the opening of the cooling slot 51 can be connected to the slot insulation 4, with the protrusion interfering with the opening of the cooling slot 51. In practical applications, adhesive sealing is generally used, as it is relatively simple to prepare and assemble. The opening of each cooling slot 51 is sealed by the slot insulation 4, forming an independent coolant flow channel that is axially continuous and closed on all four sides. The U-shaped internal cavity of the slot insulation 4 is used to wind the winding 3, which consists of multiple copper wires. Insulating slot wedges are embedded at the slot opening of the stator slot to press the winding 3 tightly.

[0029] To coordinate with the input and output of coolant in the coolant flow path, see [reference needed]. Figure 3The liquid inlet distribution chamber 2 and the liquid outlet manifold 8 are fixed at the front and rear ends of the stator core, respectively. The liquid inlet distribution chamber 2 and the liquid outlet manifold 8 are connected to the inlet and outlet of the coolant flow channel, respectively. The liquid inlet 21 of the liquid inlet distribution chamber 2 extends out of the front end cover 1 of the motor where the stator core 5 is located, and the liquid outlet 81 of the liquid outlet manifold 8 extends out of the rear end cover 9 of the motor where the stator core 5 is located.

[0030] The inlet distribution chamber 2 and the outlet manifold 8 can be found in the following references: Figure 4 and Figure 5 Both have the same structure, including a first groove that is inverted on the end face of the yoke of the stator core 5 and a second groove that is inverted on the end face of the stator teeth. The first groove is an annular groove and is connected to the coolant flow channel corresponding to the bottom inner wall. The second groove is connected to the coolant flow channel corresponding to the side inner wall. The first groove and the second groove are connected. The connected first groove and second groove, together with the end face of the yoke of the stator core 5 and the end face of the stator teeth, form a gear-shaped cavity.

[0031] It should be noted that the above-mentioned liquid inlet distribution chamber 2 and liquid outlet manifold 8 can be separate components or integrally formed with the motor end cover, that is, the liquid inlet distribution chamber 2 is integrally formed with the front end cover 1, and the liquid outlet manifold 8 is integrally formed with the rear end cover 9.

[0032] During operation, the cooling system uses insulating heat-conducting oil, hydrofluoroether, or ester-based coolants, such as dimethyl silicone oil. The coolant is pumped into the inlet distribution chamber 2 via inlet 21 by an external oil pump, and evenly distributed into the coolant channels of each stator slot. As the coolant flows axially along the entire length of the stator core 5, it directly receives heat from the stator core 5 and efficiently absorbs heat generated by the windings 3 through the slot insulation 4. The cooled coolant, after absorbing heat and increasing in temperature, flows into the outlet manifold 8 and is discharged through outlet 81, returning to the external radiator for cooling and reuse.

[0033] The aforementioned cooling structure features cooling slots 51 on the inner wall of the stator slots. It creatively utilizes the slot insulation 4 as the sealing surface of the cooling slots 51, eliminating the need for additional cooling pipes inserted into the stator slots. This design minimizes the usable space of the windings 3, ensuring the stator slots are fully filled. The coolant flows within an independent, enclosed coolant channel, completely physically isolated from the windings 3. This design places relatively low demands on the insulation and chemical stability of the coolant, resulting in high system reliability. Furthermore, the heat from the windings 3 is conducted to the stator core 5 and the coolant through the slot insulation 4, while the heat from the stator core 5 is directly transferred to the coolant. The short heat conduction path and minimal thermal resistance efficiently remove heat from the windings 3 and the stator core 5, significantly reducing the temperature rise of the windings 3.

[0034] Based on the above cooling structure, this application also discloses a motor, namely... Figure 1The motor includes the aforementioned cooling structure, which not only provides high cooling efficiency but also maintains the effective space of the stator slots. In addition to the cooling structure, the motor also includes a permanent magnet 6, a rotor core 7, and a housing 10. This motor is simply an existing motor structure with the added cooling structure; therefore, the connection structures of the remaining components are existing technology and will not be detailed here.

[0035] Based on the aforementioned motor, this application also discloses an electric device including the aforementioned motor, i.e., a device using the aforementioned motor as a drive, which enhances the performance, reliability, and lifespan of the motor due to the presence of an efficient cooling structure, thereby improving the performance, reliability, and lifespan of the device.

[0036] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A cooling structure, characterized in that, It includes several cooling grooves opened along the axial direction of the stator core on the inner wall of the stator slot, the opening of the cooling grooves being sealed by slot insulation to form a coolant flow channel; wherein, the slot insulation is slot insulation set in the stator slot for accommodating the winding.

2. The structure according to claim 1, characterized in that, The stator core is provided with a liquid inlet distribution chamber and a liquid outlet manifold at its front and rear ends, respectively. The liquid inlet distribution chamber and the liquid outlet manifold are respectively connected to the inlet and outlet of the coolant flow channel. The liquid inlet of the liquid inlet distribution chamber extends out of the front end cover of the motor where the stator core is located, and the liquid outlet of the liquid outlet manifold extends out of the rear end cover of the motor where the stator core is located.

3. The structure according to claim 2, characterized in that, Both the liquid inlet distribution chamber and the liquid outlet manifold include a first groove that is upside down on the end face of the stator core yoke and a second groove that is upside down on the end face of the stator teeth. The first groove is an annular groove, and the first groove and the second groove are connected.

4. The structure according to claim 3, characterized in that, The cooling trough is provided on the bottom inner wall and at least one side inner wall of the stator slot; The first groove is connected to the coolant flow channel corresponding to the bottom inner wall, and the second groove is connected to the coolant flow channel corresponding to the side inner wall.

5. The structure according to claim 4, characterized in that, All cooling slots are parallel and independent of each other, and the cross-section of the cooling slots can be any one of rectangle, trapezoid, triangle and semicircle.

6. The structure according to claim 1, characterized in that, A sealing layer is provided between the tank insulation and the edge of the cooling tank opening to achieve an adhesive seal; or, the tank insulation is provided with a protrusion that matches the opening of the cooling tank, and the protrusion is interference-fitted into the opening of the cooling tank.

7. The structure according to claim 1 or 6, characterized in that, The slot insulation is a multi-layer composite insulating sheet, which includes at least an insulating reinforcement layer and a liquid-resistant layer that wraps around the insulating reinforcement layer.

8. An electric motor, characterized in that, Includes the structure described in any one of claims 1 to 7.

9. An electric device, characterized in that, Includes the motor as described in claim 8.

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