Motor and compressor

Abstract

The invention discloses a motor and a compressor. The motor comprises a housing, a rotor assembly and a stator assembly. The rotor assembly is arranged in the machine shell and comprises a rotor iron core and a permanent magnet, and the permanent magnet is embedded in the rotor iron core. The stator assembly is arranged in the machine shell and arranged on the periphery of the rotor assembly in a sleeving mode, a first gap is formed between the stator assembly and the rotor assembly, the stator assembly comprises a stator iron core and aluminum windings, a plurality of stator teeth are arranged on the inner wall face of the stator iron core at intervals, a stator groove is formed between every two adjacent stator teeth, the number of the aluminum windings is multiple, and the number of the aluminum windings is multiple. The plurality of aluminum windings are wound on the plurality of stator teeth in a one-to-one correspondence manner; and a second gap is formed between two adjacent aluminum windings in the stator slots. Along the axis direction of the stator core, the projection area of the first gap and the projection area of the second gap satisfy the relational expression: 1.4 < = S4 / S5 < = 1.55. The problem that the temperature rise of the motor is too high in the prior art is at least solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration, in particular to a motor and a compressor. BACKGROUND

[0002] The cost of the motor in the compressor is relatively large, and the stator core in the existing motor is usually wound with copper winding. Due to the increase of copper price, the cost of the motor is greatly increased. In order to reduce the cost of the motor, some existing motors use winding made of other low-cost materials to replace copper winding, such as aluminum winding, so as to reduce the manufacturing cost of the motor.

[0003] However, the motor using aluminum winding has a high temperature rise due to the large resistance of the aluminum winding. SUMMARY

[0004] The main purpose of the present application is to provide a motor and a compressor to at least solve the problem of high temperature rise of the motor in the prior art.

[0005] According to one aspect of the present application, a motor is provided, which is at least used in a compressor, comprising:

[0006] A housing;

[0007] A rotor assembly, which is arranged in the housing, comprises a rotor core and a permanent magnet, and the permanent magnet is embedded in the rotor core;

[0008] A stator assembly, which is arranged in the housing and sleeved on the outer periphery of the rotor assembly, is provided with a first gap between the stator assembly and the rotor assembly, and the stator assembly comprises a stator core and an aluminum winding. The inner wall surface of the stator core is provided with a plurality of stator teeth at intervals, and each two adjacent stator teeth has a stator slot therebetween. The aluminum winding comprises a plurality of aluminum windings, and each two adjacent aluminum windings in the stator slot has a second gap therebetween.

[0009] Wherein, along the axial direction of the stator core, the projection area S4 of the first gap and the projection area S5 of the second gap satisfy the relationship: 1.4≤S4 / S5≤1.55.

[0010] Further, the second gap extends along the slot depth direction of the stator slot, and the extension length of the second gap is the same as the maximum slot depth of the stator slot.

[0011] Further, the distance W2 between the two adjacent stator slots and the width W1 of the second gap satisfy the relationship: 2.95≤W2 / W1≤3.17.

[0012] Further, the interval W2 between two adjacent stator slots satisfies the relationship: 8mm≤W2≤9.5mm.

[0013] Further, the ratio D2 / D1 between the outer diameter D1 of the stator core and the inner diameter D2 of the stator core satisfies the relationship: 0.45≤D2 / D1≤0.52.

[0014] Further, the outer diameter D1 of the stator core satisfies the relationship: 96mm≤D1≤108mm.

[0015] Further, the moment of inertia I of the rotor assembly satisfies the relationship: 0.000175kg·m 2 ≤I≤

[0016] 0.000280kg·m 2 .

[0017] Further, the ratio D3·L1·ρ / 16 of the outer diameter D3 of the rotor core, the length L1 of the rotor core along the self-axis direction and the density ρ of the rotor core satisfies the relationship: D3 4 ·L1·ρ / 16>0.00011kg·m 2 .

[0018] Further, the magnetic flux density Br of the permanent magnet satisfies the relationship: 1.1T≤Br≤1.5T when the temperature of the permanent magnet is 25℃.

[0019] In another aspect, the application also provides a compressor comprising the motor described above.

[0020] Compared with the prior art, in the application, a second gap is arranged between two adjacent aluminum windings, and the second gap can be cooled by the refrigerant or air flow to improve the stability of the motor. In addition, the projection area S4 of the first gap in the motor is usually unchanged, and when the relationship 1.4≤S4 / S5≤1.55 is satisfied between the projection area S4 of the first gap and the projection area S5 of the second gap, the projection area S5 of the second gap is larger, so that the flow resistance in the second gap is smaller, and the refrigerant or air flow can pass through the second gap more easily and quickly, thereby taking away the heat on the aluminum winding, further improving the heat dissipation effect of the motor, and solving the problem of high temperature rise of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings described herein are used to provide further understanding of the application, and form a part of the application. The schematic embodiments of the application and the description thereof are used to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0022] Figure 1This is a schematic diagram of the stator assembly and rotor assembly disclosed in this application;

[0023] Figure 2 This is a schematic diagram of the rotor assembly disclosed in this application;

[0024] Figure 3 This is a data comparison diagram of Embodiment 1, Embodiment 2 and Comparative Example 1 in this application;

[0025] Figure 4 This is a data comparison chart of Embodiments 3 and 4 and Comparative Example 2 in this application;

[0026] Figure 5 This is a data comparison chart of Embodiments 5 and 6 and Comparative Example 3 in this application;

[0027] Figure 6 This is a data comparison chart of Embodiments 7, 8 and Comparative Example 4 in this application.

[0028] The above figures include the following reference numerals:

[0029] 10. Rotor assembly; 11. Rotor core; 12. Permanent magnet; 20. Stator assembly; 21. Stator core; 22. Aluminum winding; 30. First gap; 111. Mounting slot; 112. Flow hole; 201. Stator slot; 202. Second gap; 211. Stator tooth. Detailed Implementation

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0032] 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. 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 have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0033] See Figures 1 to 6 As shown, according to an embodiment of this application, a compressor is provided, the compressor including a motor, the motor including a housing (not shown), a rotor assembly 10 and a stator assembly 20.

[0034] The rotor assembly 10 is housed within the casing and includes a rotor core 11 and a permanent magnet 12, with the permanent magnet 12 embedded within the rotor core 11. The stator assembly 20 is housed within the casing and fitted around the outer periphery of the rotor assembly 10. A first gap 30 is provided between the stator assembly 20 and the rotor assembly 10. Multiple stator teeth 211 are spaced apart on the inner wall of the stator core 21, with a stator slot 201 between two adjacent stator teeth 211. Multiple aluminum windings 22 are wound one-to-one around the multiple stator teeth 211. A second gap 202 is provided between two adjacent aluminum windings 22 in the stator slot 201. Along the axial direction of the stator core 21, the projected area S4 of the first gap 30 and the projected area S5 of the second gap 202 satisfy the relationship: 1.4 ≤ S4 / S5 ≤ 1.55.

[0035] Specifically, when aluminum windings 22 are used instead of copper windings, the resistance of aluminum windings 22 of the same size is approximately 1.6 times that of copper windings. This results in greater heat generation from the aluminum windings 22 during motor operation, ultimately causing the motor to overheat and malfunction. In this embodiment, a second gap 202 is provided between two adjacent aluminum windings 22. The second gap 202 allows refrigerant or airflow to dissipate heat from the motor, thereby improving motor stability. Furthermore, the projected area of ​​the first gap 30 in the motor typically remains constant. When the projected area S4 of the first gap 30 and the projected area S5 of the second gap 202 satisfy the relationship 1.4 ≤ S4 / S5 ≤ 1.55, the projected area S5 of the second gap 202 is larger, resulting in lower flow resistance within the second gap 202. This allows refrigerant or airflow to pass through the second gap 202 more easily and quickly, carrying away heat from the aluminum windings 22, further improving the motor's heat dissipation effect and solving the problem of excessive motor temperature rise. The values ​​of S4 / S5 can be 1.4, 1.42, 1.44, 1.46, 1.48, 1.5, 1.52, 1.54 and 1.55.

[0036] Furthermore, the second gap 202 extends along the groove depth direction of the stator groove 201, and the extension length of the second gap 202 is the same as the maximum groove depth of the stator groove 201.

[0037] Specifically, an aluminum winding 22 is wound within two adjacent stator slots 201, and the two adjacent aluminum windings 22 form a second gap 202 within the stator slots 201. In this embodiment, the extension length of the second gap 202 is the same as the maximum slot depth of the stator slots 201, so that the refrigerant or airflow can dissipate heat on the outer circumferential surface of the aluminum winding 22 along the depth direction of the stator slots 201 after passing through the second gap 202, thereby further improving the heat dissipation effect of the motor. It should be noted that in this embodiment, the projected area of ​​the second gap 202 along the axial direction of the rotor core 11 is the product of the maximum depth L2 of the stator slots 201 and the minimum distance between two adjacent stator teeth 211. The maximum depth L2 of the stator slots 201 is the depth of the second gap. In this embodiment, L2 can also be expressed as the maximum distance from the inner circumferential surface of the stator core 21 to the bottom of the stator slots 201. The minimum distance between two adjacent stator teeth 211 is approximately the width W1 of the second gap 202, i.e., S5 = L2·W1. It is worth mentioning that, in actual products, due to differences in manufacturing processes, manufacturing temperatures, and the winding method of the aluminum winding 22, the width of the second gap 202 may differ from the value of the minimum distance between two adjacent stator teeth 211, and the actual width of the second gap 202 is difficult to measure; therefore, this embodiment is only for the sake of simple description, and the width of the second gap 202 is approximated as the minimum distance W1 between two adjacent stator teeth 211.

[0038] Furthermore, the distance W2 between two adjacent stator slots 201 and the width W1 of the second gap 202 satisfy the following relationship: 2.95 ≤ W2 / W1 ≤ 3.17. When W2 / W1 satisfies the above relationship, W2 is smaller and W1 is larger, resulting in a larger overall volume of the stator slots 201 and the second gap 202. This allows for the selection of thicker aluminum windings 22. Simultaneously, the larger heat dissipation area of ​​the second gap 202 further improves the heat dissipation efficiency of the stator core 21 and the aluminum windings 22. However, when W2 / W1 is less than 2.95, on the one hand, W2 may be too small, leading to weaker structural strength of the stator teeth 211, making them prone to damage under external forces; on the other hand, W1 may be too large, causing the volume of the second gap 202 to occupy too much of the stator slot 201 volume, preventing the selection of thicker aluminum windings 22 for the stator windings. When W2 / W1 is greater than 3.17, it may be because W2 is too large, resulting in a smaller overall volume of stator slot 201, making it impossible to wind a thicker aluminum winding 22. It may also be because W1 is too narrow, which reduces the heat dissipation capacity of the stator core 21, leading to excessive temperature rise in the motor. The values ​​of W2 / W1 can be 2.95, 2.98, 3, 3.03, 3.06, 3.1, 3.13, 3.15, and 3.17.

[0039] Furthermore, the spacing W2 between two adjacent stator slots 201 satisfies the following relationship: 8mm≤W2≤9.5mm.

[0040] Specifically, when W2 satisfies the above relationship, the overall volume of the stator slot 201 will not be too large, resulting in a thin stator tooth 211 and thus reducing the structural strength of the stator core 21. Simultaneously, the overall volume of the stator slot 201 will not be too small, resulting in a small volume of the second gap 202 within the stator slot 201 and the inability to install a thicker aluminum winding 22 within the stator slot 201. The value of W2 can be 8mm, 8.2mm, 8.4mm, 8.6mm, 8.8mm, 9mm, 9.2mm, 9.4mm, and 9.5mm. When W2 is less than 8mm, the overall volume of the stator slot 201 is too large, resulting in insufficient structural strength of the stator core 21 and stator tooth 211. When W2 is greater than 9.5mm, the overall volume of the stator slot 201 is too small, resulting in a reduced space for the second gap 202 and decreased heat dissipation capacity of the aluminum winding 22.

[0041] Furthermore, the outer diameter D1 of the stator core 21 and the inner diameter D2 of the stator core 21 satisfy the following relationship: 0.45≤D2 / D1≤0.52.

[0042] In this embodiment, by limiting the ratio between D1 and D2, the length of the second gap 202 in the radial direction is changed, thereby altering the heat dissipation effect of the second gap 202 on the aluminum winding 22. Specifically, in this embodiment, D1 is usually a fixed value. The size of the outer diameter D3 of the rotor core 11 is changed by adjusting the size of D2. When D2 / D1 is less than 0.45, D2 is small, meaning the value of D3 is too small, resulting in an excessively small overall volume of the rotor core 11. This reduces the heat dissipation capacity of the rotor core 11 and, due to its small size and mass, results in a small moment of inertia, affecting the stability of motor control. Conversely, when D2 / D1 is greater than 0.52, the value of D2 is too large. This reduces the area of ​​the stator slot 201 and the second gap 202, affecting the heat dissipation capacity of the stator assembly 20. Furthermore, the reduced area of ​​the stator slot 201 leads to a smaller wire diameter in the aluminum winding 22, increasing resistance and raising the temperature rise. When D2 / D1 satisfies the relationship 0.45≤D2 / D1≤0.52, the space within the stator slot 201 is larger, allowing for the winding of a thicker aluminum winding 22 on the stator teeth 211. This reduces the resistance of the aluminum winding 22, preventing excessive heat generation during operation. Furthermore, the stator core 21 is not too thin, preventing excessive structural strength. The thicker stator core 21 also allows for a deeper second gap 202, improving heat dissipation. Simultaneously, satisfying the above relationship results in a more balanced manufacturing cost for both the rotor core 11 and the stator core 21. In this embodiment, the values ​​of D2 / D1 can be 0.45, 0.46, 0.47, 0.48, 0.49, 0.5, 0.51, and 0.52.

[0043] Furthermore, the rotor core 11 has multiple flow holes 112 extending along its own axis. Along the axis of the rotor assembly 10, the sum of the projected area S1 of the rotor core 11 and the projected area S2 of the multiple flow holes 112, S3, satisfies the relationship: 0.11≤S3 / S1≤0.16.

[0044] Specifically, the flow holes 112 allow refrigerant, airflow, or coolant to cool the rotor core 11, thus preventing the motor from overheating. Furthermore, when S3 / S1 satisfies the above relationship, the sum of the projected areas S2 and S3 of the multiple flow holes 112 relative to the sum of the projected areas S1 of the rotor core 11 is relatively large, allowing the refrigerant, airflow, or coolant to pass through the flow holes 112 more effectively, further improving the motor's heat dissipation. However, when S3 / S1 is less than 0.11, the sum of the projected areas S2 and S3 of the multiple flow holes 112 relative to the sum of the projected areas S1 of the rotor core 11 is too small, resulting in high flow resistance within the flow holes 112 and ultimately poor heat dissipation capacity. Conversely, when S3 / S1 is greater than 0.16, the sum of the projected areas S2 and S3 of the multiple flow holes 112 relative to the sum of the projected areas S1 of the rotor core 11 is too large, resulting in insufficient structural strength of the rotor core 11, which may lead to damage to the rotor core 11 during high-speed motor operation. In this embodiment, the values ​​of S3 / S1 can be 0.11, 0.12, 0.13, 0.14, 0.15, and 0.16.

[0045] Furthermore, the outer diameter D1 of the stator core 21 satisfies the relationship: 96mm ≤ D1 ≤ 108mm. When D1 satisfies this relationship, the stator core 21 will not be too large, resulting in excessively high manufacturing costs and low space utilization. Conversely, the stator core 21 will not be too small, leading to poor heat dissipation. When D1 is less than 96mm, the stator core 21 is too small, potentially resulting in a smaller overall volume of the stator slot 201 or a smaller rotor core 11, which in turn makes the flow hole 112 too small, ultimately causing poor heat dissipation of the motor. Conversely, when D1 is greater than 108mm, the stator core 21 occupies too much volume, resulting in low space utilization and excessively high material costs. The value of D1 can be 96mm, 97mm, 98mm, 99mm, 100mm, 101mm, 102mm, 103mm, 104mm, 105mm, 106mm, 107mm and 108mm.

[0046] Furthermore, the moment of inertia I of the rotor assembly 10 satisfies the following relationship: 0.000175 kg·m 2 ≤I≤0.000280kg·m 2 .

[0047] In this embodiment, since the motor is mainly used in the compressor, the moment of inertia of the rotor assembly 10 is not only related to the mass of the rotor assembly 10, but also to the influence of the compressor on the rotor assembly 10. For example, the refrigerant in the flow hole 112 will have a certain impact on the moment of inertia of the rotor assembly 10. Furthermore, in order to improve the efficiency of the motor using aluminum windings 22, it is usually necessary to reduce the inner diameter D2 of the stator core 21 to reduce the iron and copper losses of the motor, thereby improving the efficiency of the motor. However, after reducing the inner diameter D2 of the stator core 21, in order for the motor to maintain a high speed quickly, the moment of inertia should be set within a small range, i.e., I should satisfy the relationship: 0.000175 kg·m 2 ≤I≤0.000280kg·m 2 .

[0048] Specifically, when the moment of inertia I of rotor assembly 10 is less than 0.000175 kg·m 2 When the moment of inertia I of rotor assembly 10 is too small, its moment of inertia matrix becomes more dispersed when the motor load changes, making it more susceptible to external disturbances and leading to a decrease in the control accuracy and stability of the motor. Furthermore, a small moment of inertia of rotor assembly 10 may cause it to generate greater vibration and noise at high speeds, and make drive control more difficult; it may also affect other components in the motor. However, when I is greater than 0.00028 kg·m... 2 If the time required for the motor to reach a stable speed is too long, the motor's efficiency will decrease. The value of I can be 0.000175 kg·m. 2 0.000190 kg·m 2 0.00020 kg·m 2 0.00021 kg·m 2 0.00022 kg·m 2 0.00023 kg·m 2 0.00024 kg·m 2 0.00025 kg·m 2 0.00026 kg·m 2 0.00027 kg·m 2 0.00028 kg·m 2 .

[0049] Furthermore, the outer diameter D3 of the rotor core 11, the length L1 of the rotor core 11 along its own axis, and the density ρ of the rotor core 11 satisfy the following relationship: D3 4 ·L1·ρ / 16>0.00011kg·m 2 .

[0050] Specifically, D34 ·L1·ρ / 16 is a simplified representation of the moment of inertia of rotor core 11 without considering the influence of refrigerant. When D3 4 ·L1·ρ / 16 is greater than 0.00011 kg·m 2 At this time, the moment of inertia of the rotor core 11 will not be set too low, resulting in a more dispersed moment of inertia matrix of the rotor core 11 when the motor load changes, making it more susceptible to external disturbances and ultimately leading to a decrease in the control accuracy and stability of the motor. Furthermore, when D3... 4 ·L1·ρ / 16 is less than or equal to 0.00011 kg·m 2 If the moment of inertia of the rotor core 11 is too small, the motor will be more prone to noise and vibration during rotation, thus reducing its performance. Of course, to avoid the rotor core 11 taking too long to reach high speeds and affecting motor efficiency, the moment of inertia of the rotor core 11 itself should not be too large either; its maximum value should not be greater than or equal to 0.00028 kg·m. 2 D3 4 The value of ·L1·ρ / 16 can be 0.00012 kg·m 2 0.00015 kg·m 2 0.00018 kg·m 2 0.0002 kg·m 2 0.00023 kg·m 2 0.00026 kg·m 2 .

[0051] Furthermore, when the temperature of the permanent magnet 12 is 25℃, the magnetic flux density Br of the permanent magnet 12 satisfies the relationship: 1.1T≤Br≤1.5T.

[0052] Specifically, when assembling the motor, different models of permanent magnets 12 need to be selected, and the magnetic flux density Br of different models of permanent magnets 12 varies. If the selected permanent magnet 12 is at a temperature of 25℃ and its magnetic flux density Br is less than 1.1T, when the motor operates, the temperature of the permanent magnet 12 rises, and the magnetic flux density Br decreases, which may lead to a decrease in the motor's magnetic flux and thus affect the motor's operating efficiency. Generally speaking, the higher the magnetic flux density of the permanent magnet 12, the higher its cost. Therefore, if the selected permanent magnet 12 is at a temperature of 25℃ and its magnetic flux density Br is greater than 1.5T, the cost of the permanent magnet 12 is too high. The value of Br can be 1.1T, 1.2T, 1.3T, 1.4T, or 1.5T.

[0053] Furthermore, multiple flow holes 112 are spaced apart around the axis of the rotor core 11; the projection surface of the flow holes 112 along the axial direction of the rotor core 11 includes at least one of four shapes: circular, elliptical, rectangular, and triangular.

[0054] Specifically, the spaced arrangement of multiple flow holes 112 around the axis of the rotor core 11 ensures a uniform mass distribution on the rotor core 11 and allows for even heat dissipation from the rotor core 11. This prevents uneven mass distribution across the rotor core 11 caused by uneven arrangement of the multiple flow holes 112, which could ultimately affect motor rotation. Furthermore, when the projected surface of the flow holes 112 is set to a circle, ellipse, rectangle, or triangle, these regular shapes facilitate machining on the rotor core 11.

[0055] Furthermore, the rotor core 11 includes a plurality of mounting slots 111 spaced apart around the axis of the rotor core 11, and the plurality of mounting slots 111 extend along the axial direction of the rotor core 11; the permanent magnet 12 includes a plurality of permanent magnets 12, and the plurality of permanent magnets 12 are embedded in the plurality of mounting slots 111 in a one-to-one correspondence.

[0056] Specifically, multiple permanent magnets 12 are spaced apart along the axis, which makes the magnetic field distribution in the motor more uniform; at the same time, the multiple permanent magnets 12 are evenly distributed to make the mass distribution of the rotor assembly 10 uniform, thereby preventing the rotor assembly 10 from deflecting and affecting the working efficiency of the motor.

[0057] Furthermore, disregarding the grooves on the rotor core 11 and the stator core 21, i.e., disregarding the influence of the outlines of the rotor core 11 and the stator core 21, the area S1 of the projected surface of the rotor core 11 in this embodiment can be calculated using the following formula: S1 = 0.25·π·(D3^2-D4^2), where D4 is the inner diameter of the rotor core 11. The area S4 of the first gap 30 can be calculated using the following formula: S4 = π·((D2 / 2)^2-(D3 / 2)^2).

[0058] The following embodiments are also provided in this application to illustrate the ratios of S3 / S1 and D2 / D1:

[0059] Example 1:

[0060] When S3 / S1 is 0.128, the rotor assembly 10 temperature is 93℃ and the demagnetizing current of the motor is 25A when the motor is working normally.

[0061] Comparative Example 1:

[0062] When S3 / S1 is 0.036, the temperature of rotor assembly 10 is 98℃ and the demagnetizing current of the motor is 22A when the motor is working normally.

[0063] By comparing Example 1 and Comparative Example 1, it can be found that when S3 / S1 < 0.11, the temperature of the rotor assembly 10 during normal operation of the motor increases significantly and the demagnetizing current decreases, which makes the permanent magnet 12 in the motor prone to demagnetization, ultimately causing the motor to fail to work normally.

[0064] Example 2:

[0065] When S3 / S1 is 0.16, the rotor assembly 10 temperature is 92℃ and the demagnetizing current of the motor is 27A when the motor is working normally.

[0066] Referring to Table 1, a comparison of Examples 1 and 2 shows that, compared to Example 1, the ratio of S3 / S1 in Comparative Example 1 is larger, and S3 / S1 satisfies the relationship: 0.11 ≤ S3 / S1 ≤ 0.16. This increases the proportion of the volume of the flow hole 112 to the volume of the rotor core 11, thus improving the heat dissipation efficiency of the rotor core 11 and reducing its temperature during normal operation. However, when S3 / S1 is too large, the temperature reduction effect of the rotor core 11 is significantly reduced, i.e., the temperature drops from 93°C when S3 / S1 is 0.11 to 92°C when S3 / S1 is 0.16. Considering the stability and structural strength of the rotor core 11, the value of S3 / S1 should be less than or equal to 0.16; otherwise, the rotor core 11 may be damaged due to its low structural strength during long-term high-speed rotation. Meanwhile, by testing the demagnetizing current of the permanent magnet 12, it can be found that the demagnetizing current is significantly increased, thereby preventing the permanent magnet 12 from easily demagnetizing during motor operation. By comparing Example 2 with Comparative Example 1, it can be seen that the temperature of the rotor core 11 is significantly reduced in Comparative Example 2, and the demagnetizing current of the permanent magnet 12 is increased.

[0067] Table 1:

[0068] S3 / S1 Rotor core temperature (°C) Permanent magnet demagnetization current (A) 0.036 98 22 0.128 93 25 0.16 92 27

[0069] Example 3:

[0070] The ratio of D2 to D1 in the motor is 0.504, the manufacturing cost of the motor is calculated to be 70.9 yuan, and the 60Hz performance of the motor according to GB standards is 90.2%.

[0071] Example 4:

[0072] The ratio of D2 to D1 in the motor is 0.52, the manufacturing cost of the motor is calculated to be 71.12 yuan, and the 60Hz performance of the motor according to GB standards is 90.08%.

[0073] Comparative Example 2:

[0074] The ratio of D2 to D1 in the motor is 0.567, the manufacturing cost of the motor is calculated to be 92.6 yuan, and the 60Hz performance of the motor according to GB standards is 90.24%.

[0075] According to Table 2, by comparing Examples 3 and 4 with Comparative Example 2, it can be found that as D2 / D1 continuously increases, the 60Hz performance of the motor according to GB standards remains almost unchanged, while the material cost of the motor continuously increases. This is because when D2 / D1 increases, the area of ​​the stator slot 201 is smaller, resulting in a smaller radius of the aluminum winding 22. This leads to an increase in the resistance of the aluminum winding 22, an increase in the temperature rise of the motor, and a decrease in performance. To ensure that the motor performance remains unchanged, the only way is to continuously increase the radial thickness of the stator core 21, thereby reducing the area of ​​the stator slot 201. It is worth mentioning that the motor cost is mainly due to the rise in copper prices; changes in the thickness and size of the stator and rotor cores have a relatively small impact on the cost. The cost reduction in this application refers to replacing the copper wire winding with an aluminum wire winding 22 and optimizing the design dimensions of the rotor core 11 and stator core 21 to avoid excessive temperature rise and low motor efficiency caused by replacing the aluminum winding 22. This allows the motor using the aluminum winding 22 to achieve the same efficiency as the motor using the copper winding. Although the amount of material used may not necessarily be reduced, and may even increase slightly, the change in materials significantly reduces the manufacturing cost of the motor.

[0076] Table 2:

[0077] D2 / D1 Motor cost (yuan) GB standard 60hz performance (%) 0.504 70.9 90.2 0.52 71.12 90.08 0.567 92.6 90.24

[0078] This application also provides the following embodiments to illustrate the effects of S4 / S5 and the effects of the value of W2.

[0079] Example 5:

[0080] When S4 / S5 is 1.4, the temperature on stator core 21 is 124.8℃.

[0081] Example 6:

[0082] When S4 / S5 is 1.55, the temperature on stator core 21 is 125.6℃.

[0083] Comparative Example 3:

[0084] When S4 / S5 is 2.15, the temperature on stator core 21 is 126.5℃.

[0085] According to Table 3, by comparing Example 5, Example 6 and Comparative Example 3, it can be found that as the value of S4 / S5 increases, the temperature on the stator core 21 increases. This is because the projected area of ​​the second gap 202 decreases, which in turn reduces the heat dissipation capacity of the stator core 21. Therefore, the larger S4 / S5 is, the higher the temperature on the stator core 21 is.

[0086] Table 3:

[0087]

[0088]

[0089] Example 7:

[0090] W2 is 8mm thick, and the current density on aluminum winding 22 is 10.7A / m. 2 .

[0091] Example 8:

[0092] W2 is 9.5mm thick, and the current density on the aluminum winding 22 is 12.28A / m. 2 .

[0093] Comparative Example 4:

[0094] W2 is 11mm thick, and the current density on aluminum winding 22 is 14.19A / m. 2 .

[0095] According to Table 4, by comparing Examples 3, 4 and Comparative Example 2, it can be seen that when the width W2 between two adjacent stator slots 201 is larger, the current density on the aluminum winding 22 is higher, which means that the heat generated on the aluminum winding 22 is higher and the temperature rise is higher. This is because when W2 is larger, the overall volume of the stator slot 201 is smaller, and the volume of the second gap 202 is reduced accordingly, resulting in a reduction in the heat dissipation capacity of the stator core 21.

[0096] Table 4:

[0097] W2 (mm) Current density (A / m 2 ) 8 10.7 9.5 12.28 11 14.19

[0098] In summary, this application has at least the following beneficial effects: By limiting the ratio between the projected area S4 of the first gap 30 and the projected area S5 of the second gap 202 to satisfy the relationship: 1.4≤S4 / S5≤1.55, the projected area S5 of the second gap 202 is made larger, thereby improving the heat dissipation effect of the stator core 21. Furthermore, by limiting the relationship between the spacing W2 between two adjacent stator slots 201 and the width W1 of the second gap 202 to satisfy the relationship: 2.95≤W2 / W1≤3.17, the second gap 202 and the stator slots 201 have adequate space, allowing the aluminum winding 22 to be of a thicker type. Finally, this application limits the value of W2 to 8mm≤W2≤9.5mm. When W2 is within the above range, the space between the second gap 202 and the stator slot 201 will not be too small, resulting in a reduction in the heat dissipation capacity of the motor. The space between the second gap 202 and the stator slot 201 will not be too large, resulting in a low structural strength of the stator core 21.

[0099] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0100] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0101] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An electric machine, at least for a compressor, characterized in that, Comprising: a casing; a rotor assembly (10) disposed in the casing, the rotor assembly (10) comprising a rotor core (11) and a permanent magnet (12) embedded in the rotor core (11); a stator assembly (20) disposed in the casing and sleeved on the outer periphery of the rotor assembly (10), a first gap (30) being provided between the stator assembly (20) and the rotor assembly (10), the stator assembly (20) comprising a stator core (21) and aluminum windings (22), an inner wall surface of the stator core (21) being provided with a plurality of stator teeth (211) at intervals, each two adjacent stator teeth (211) having a stator slot (201) therebetween, the aluminum windings (22) comprising a plurality of, each two adjacent aluminum windings (22) in the stator slot (201) having a second gap (202) therebetween; wherein, along the axial direction of the stator core (21), the projected area S4 of the first gap (30) and the projected area S5 of the second gap (202) satisfy the relationship: 1.4≤S4 / S5≤1.

55.

2. The electric machine of claim 1, wherein, The second gap (202) extends along the slot depth direction of the stator slot (201), and the extension length of the second gap (202) is the same as the maximum slot depth of the stator slot (201).

3. The electric machine of claim 1, wherein, The spacing W2 between each two adjacent stator slots (201) and the width W1 of the second gap (202) satisfy the relationship: 2.95≤W2 / W1≤3.

17.

4. The electric machine of claim 1, wherein, The spacing W2 between each two adjacent stator slots (201) satisfies the relationship: 8mm≤W2≤9.5mm.

5. The electric machine of claim 1, wherein, The outer diameter D1 of the stator core (21) and the inner diameter D2 of the stator core (21) satisfy the relationship: 0.45≤D2 / D1≤0.

52.

6. The electric machine of any one of claims 1 to 5, characterized by The outer diameter D1 of the stator core (21) satisfies the relationship: 96mm≤D1≤108mm.

7. The electric machine of any one of claims 1 to 5, wherein, The moment of inertia I of the rotor assembly (10) satisfies the relationship: 0.000175 kg-m 2 ≤ I ≤ 0.000280 kg-m 2 .

8. The electric machine of any one of claims 1 to 5, characterized by The outer diameter D3 of the rotor core (11), the length LI of the rotor core (11) in the direction of its own axis, and the density p of the rotor core (11) satisfy the relationship: D3 4 · LI · p / 16 > 0.00011 kg·m 2 .

9. The electric machine of any one of claims 1 to 5, wherein, When the temperature of the permanent magnet (12) is 25℃, the magnetic flux density Br of the permanent magnet (12) satisfies the relationship: 1.1T≤Br≤1.5T.

10. A compressor characterized by, The compressor comprises the motor of any one of claims 1 to 9.

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