Motors, compressors, and cooling equipment

Abstract

This application discloses a motor, a compressor, and a cooling device, the motor comprising a stator and a rotor, the stator comprising a plurality of spaced stator teeth, the ends of the stator teeth toward the axis of the stator having tooth shoes, a plurality of mounting grooves provided in the rotor, the plurality of mounting grooves spaced apart along the circumferential direction of the rotor, permanent magnets mounted in the mounting grooves, magnetic barrier grooves provided at opposite ends of the mounting grooves, both magnetic barrier grooves extending toward the d-axis, the angle between the connection line between each of the opposing ends of the two magnetic barrier grooves and the center of the rotor being θ1, the angle between the connection line between each of the opposing ends of the tooth shoe and the center of the rotor being θ2, and |θ1-θ2| < a predetermined angle.

Description

Technical Field

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[0001] This application claims the priority of a Chinese patent application with the application number 202310294343.2, filed on March 22, 2023, and all of its content is incorporated herein by reference.

[0002] This application relates to the technical field of cooling equipment, particularly to motors, compressors, and cooling equipment.

Background Art

[0003] In recent years, due to the strong development of clean energy and new energy vehicles, permanent magnet synchronous motors based on neodymium iron boron magnets have obtained a wider range of applications. The demand for rare earth materials in the world market has increased significantly, and the price of rare earth elements has also increased substantially. Neodymium iron boron magnets are one of the three important materials for permanent magnet motors. With the increase in the price of rare earth elements, the cost of motor materials has increased. Therefore, how to improve the utilization rate of magnets and give full play to the material properties of magnets is an urgent and continuous issue in motor design.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The main object of this application is to propose a motor aimed at improving the utilization rate of magnets.

Means for Solving the Problems

[0005] To achieve the above objective, the motor according to this application includes a stator having a plurality of spaced-apart stator teeth, the ends of the stator teeth facing the stator axis having tooth shoes, and a rotor having a plurality of mounting grooves inside, the plurality of mounting grooves being spaced apart along the circumferential direction of the rotor, permanent magnets being mounted in the mounting grooves, magnetic barrier grooves being provided at both opposing ends of the mounting grooves, both of the magnetic barrier grooves extending toward the d-axis, the angle between the connection line between each of the opposing ends of the two magnetic barrier grooves and the center of the rotor being θ1, the angle between the connection line between each of the opposing ends of the tooth shoe and the center of the rotor being θ2, and |θ1-θ2| < a predetermined angle.

[0006] In one embodiment, the preset angle is 2° or less.

[0007] In one embodiment, the stator has Q stator teeth, and the rotor has 2P mounting grooves, where Q=12 and 2P=8.

[0008] In one embodiment, the tooth width of the stator teeth is bt, the inner diameter of the stator is D, the residual magnetic flux of the permanent magnet is Br, and |bt-Br*θ1*D*π / 865|<0.5.

[0009] In one embodiment, the width of the permanent magnet is bM, the inner diameter of the stator is D, and the condition 0.7 < 4P * bM / (D * π) < 0.78 is satisfied.

[0010] In one embodiment, 4P*bM / (D*π) = 0.75.

[0011] In one embodiment, the magnetic barrier groove further extends in a direction away from the d-axis.

[0012] In one embodiment, the mounting groove includes a first segment and a second segment that are in communication with each other and are provided at an angle, the opening of the angle formed by the first segment and the second segment is provided away from the rotor axis, and one of the permanent magnets is mounted in each of the first segment and the second segment.

[0013] In one embodiment, a demagnetizing region is provided between the first segment and the second segment such that the two permanent magnets are spaced apart relative to each other.

[0014] In one embodiment, the residual magnetic flux of the permanent magnet is Br, and Br ≥ 1.3T.

[0015] This application further proposes a compressor including the motor described above.

[0016] This application further proposes a cooling device including the compressor described above.

[0017] To more clearly illustrate the embodiments of this application or the technical concepts in the prior art, the following is a brief introduction to the drawings that may be used in the description of the embodiments or the prior art. Clearly, the drawings in the following description are only a few embodiments of this application, and those skilled in the art can obtain other drawings based on the structures shown in these drawings without any creative effort. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic diagram of the rotor structure in one embodiment of the motor of this application. [Figure 2] This is a magnified view of area A in Figure 1. [Figure 3] Figure 1 is a schematic diagram of the stator structure in the motor.

[0019] The achievement of the objectives of this application, its functional features, and advantages will be further described with reference to the drawings, along with the examples provided. [Modes for carrying out the invention]

[0020] The technical concepts of the embodiments of this application will be described clearly and completely below, together with the drawings of the embodiments of this application. Clearly, the embodiments described are only a selection of embodiments of this application, not all embodiments. All other embodiments obtained by a person skilled in the art without any creative work based on the embodiments of this application are within the scope of protection of this application.

[0021] In the embodiments of this application, if directional indicators (e.g., up, down, left, right, front, back, etc.) are involved, these directional indicators are merely for interpreting the relative positional relationships and motion conditions between each component in a specific orientation (as shown in the drawings), and if that specific orientation changes, the directional indicators will also change accordingly.

[0022] Furthermore, in the embodiments of this application, if there are descriptions of "first," "second," etc., these descriptions are merely for descriptive purposes and should not be understood as indicating or implying their relative importance or implicitly indicating the number of technical features being referred to. Thus, features limited by "first" and "second" may explicitly or implicitly include at least one such feature. Also, "and / or" appearing throughout the specification includes three parallel schemes, and taking "A and / or B" as an example, it means including scheme A, or scheme B, or a scheme that satisfies both A and B simultaneously. In addition, while the technical solutions between each embodiment can be combined with each other, this must be based on the fact that they can be realized by a person skilled in the art. If a combination of technical solutions results in a contradiction or is not feasible, then such a combination of technical solutions should be considered nonexistent and is not within the scope of protection required by this application.

[0023] In the prior art, with the strong development of clean energy and new energy vehicles, permanent magnet synchronous motors based on neodymium iron boron magnets have obtained a wider range of applications. The demand for rare earth materials in the world market has increased significantly, and the prices of rare earth elements have also increased significantly. This has led to an increase in the material cost of the motor. At this time, how to improve the utilization rate of the magnet and thereby give full play to the material properties of the magnet as much as possible is an urgent and continuous issue in the design of the motor. There are many factors that affect the utilization rate of the magnet, and one of the most important elements is how to reduce the magnetic leakage of the rotor 120.

[0024] In view of this, in this application, a motor is proposed that reduces the magnetic leakage of the rotor 120 and improves the utilization rate of the magnet.

[0025] In an embodiment of this application, as shown in FIGS. 1 to 3, this motor includes a stator 110 and a rotor 120. The stator 110 includes a plurality of stator teeth 111 provided at intervals. The end of the stator tooth 111 facing the axis of the stator 110 has a tooth shoe 112. A plurality of mounting grooves 121 are provided in the rotor 120. The plurality of mounting grooves 121 are arranged at intervals along the circumferential direction of the rotor 120. The permanent magnet 130 is mounted in the mounting groove 121. Magnetic barrier grooves 122 are provided at both opposite ends of the mounting groove 121. Both of the two magnetic barrier grooves 122 extend in the d-axis direction. The included angle between the connection line between each of the two opposite ends of the two magnetic barrier grooves 122 and the center of the rotor 120 is θ1, and the included angle formed by the connection line between each of the two opposite ends of the tooth shoe 112 and the center of the rotor 120 is θ2, and |θ1 - θ2| < a preset angle.

[0026] Specifically, multiple stator teeth 111 are formed on the inner circumference of the stator 110 at intervals, and a stator groove 113 is formed between two adjacent stator teeth 111. The stator winding is wound around the stator teeth 111, passing through the stator groove 113. The ends of the stator teeth 111 facing the axis of the stator 110 have tooth shoes 112. When the stator winding is energized, the stator winding generates an armature magnetic field, which is transmitted to the rotor 120 along the tooth shoes 112 of the iron core of the stator 110. Magnetic barrier grooves 122 are provided at both opposing ends of the mounting groove 121, forming the structure of a magnetic shielding bridge 123, thereby reducing magnetic leakage. The longer the structure of the magnetic shielding bridge 123, the better the effect of reducing magnetic leakage. Therefore, both magnetic barrier grooves 122 extend in the d-axis, thereby increasing the length of the magnetic shielding bridge 123 and reducing magnetic leakage. However, if the extension distance of the magnetic barrier groove 122 toward the d-axis is too long, the permanent magnet 130 will encroach on the silicon steel space that transmits the main magnetic flux to the stator 110. Since the stator 110 transmits magnetic force to the rotor 120 mainly via the tooth shoe 112, the area of ​​the silicon steel between the two magnetic barrier grooves 122 facing each other toward the d-axis and the area of ​​the tooth shoe 112 are close to a preset value. That is, the angle between the connection line between each of the opposing ends of the two magnetic barrier grooves 122 and the center of the rotor 120 is θ1, and the angle between the connection line between each of the opposing ends of the tooth shoe 112 and the center of the rotor 120 is θ2, and |θ1-θ2| < preset angle. This ensures transmission efficiency between the rotor 120 and the stator 110, reduces magnetic leakage, improves the utilization rate of the magnets, and improves the performance of the motor.

[0027] Of these, the magnetic barrier grooves 122 are provided at opposing ends of the mounting grooves 121. In this embodiment, the magnetic barrier grooves 122 are provided in communication with the mounting grooves 121. In other embodiments, the magnetic barrier grooves 122 and the mounting grooves 121 may be provided opposite each other with a gap between them. In this embodiment, the plurality of stator teeth 111 are uniformly arranged along the circumferential direction of the stator 110, and / or the plurality of mounting grooves 121 are uniformly arranged along the circumferential direction of the rotor 120.

[0028] Furthermore, in one embodiment, the preset angle is 2° or less. In order to improve the torque of the rotor 120 and improve the performance of the motor by ensuring that the area of ​​the silicon steel between the two magnetic barrier grooves 122 facing each other with respect to the d-axis is as close as possible to the area of ​​the tooth shoe 112, and by ensuring good main magnetic flux transmission efficiency, the preset angle is 2° or less, i.e., |θ1-θ2|<2°, meaning that the angle θ1 formed by the connection line between each end of the two magnetic barrier grooves 122 facing each other with respect to the d-axis and the center of the rotor 120 may be slightly larger than the angle θ2 formed by the connection line between each of the opposing ends of the tooth shoe 112 and the center of the rotor 120, and may be slightly smaller than the angle θ2 formed by the connection line between each of the opposing ends of the tooth shoe 112 and the center of the rotor 120.

[0029] In the proposed invention, the inner circumference of the stator 110 is provided with a plurality of stator teeth 111 spaced apart from each other, and the ends of the stator teeth 111 facing the axis of the stator 110 have tooth shoes 112, and the armature magnetic field generated by the stator winding acts on the rotor 120 mainly via the tooth shoes 112, and a plurality of mounting grooves 121 are provided inside the rotor 120, and the plurality of mounting grooves 121 are spaced apart along the circumferential direction of the rotor 120, and the permanent magnets 130 are mounted inside the mounting grooves 121, and magnetic barrier grooves 122 are provided at both opposing ends of the mounting grooves 121, and both magnetic barrier grooves 122 extend toward the d axis, thereby increasing the length of the magnetic shielding bridge 123 and reducing magnetic leakage. However, if the extension of the magnetic barrier groove 122 toward the d-axis is too long, the permanent magnet 130 will erode the space in the silicon steel that transmits the main magnetic flux to the stator 110. Therefore, the angle between the connection line between each of the opposing ends of the two magnetic barrier grooves 122 and the center of the rotor 120 is θ1, and the angle between the connection line between each of the opposing ends of the tooth shoe 112 and the center of the rotor 120 is θ2, where |θ1-θ2| < a preset angle. As a result, the area of ​​the silicon steel between the two magnetic barrier grooves 122 facing each other toward the d-axis and the area of ​​the tooth shoe 112 are close to a preset value, and the area in which the rotor 120 transmits the permanent magnet magnetic field to the stator 110 and the area in which the stator 110 transmits the armature magnetic field to the rotor 120 are within a preset range. This ensures transmission efficiency between the rotor 120 and the stator 110, reduces magnetic leakage, improves the utilization rate of the magnets, and improves the performance of the motor.

[0030] In one embodiment, referring again to Figures 1 to 3, the stator 110 has Q stator teeth 111, and the rotor 120 has 2P mounting grooves 121, where Q=12 and 2P=8. That is, in this solution, the motor adopts a 12-slot 8-pole design, and in the prior art, it is preferable to design the tooth magnetic flux density of the 12-slot 8-pole motor to be close to 1.6T. If the tooth magnetic flux density is too high, the proportion of iron material loss in the permanent magnet 130 becomes relatively large, increasing the amount of permanent magnet 130 used and potentially resulting in less favorable motor efficiency. On the other hand, if the tooth magnetic flux density is too low, the consumption of copper material in the permanent magnet 130 becomes large, potentially leading to a significant loss of motor efficiency. Therefore, in order to ensure motor efficiency, it is preferable to design the magnetic flux density to be close to 1.6T.

[0031] Furthermore, in one embodiment, the tooth width of the stator teeth 111 is bt, the inner diameter of the stator 110 is D, and the residual magnetic flux of the permanent magnet 130 is Br, satisfying |bt-Br*θ1*D*π / 865|<0.5. Specifically, |bt-Br*θ1*D*π / 865|<0.5 is mainly used to limit the relative magnitudes of the tooth width bt of the stator teeth 111, the inner diameter D of the stator 110, and the residual magnetic flux Br of the permanent magnet 130, thereby ensuring that the losses of the stator 110 (hereinafter abbreviated as iron loss) and the losses of the stator windings wound around the stator 110 (hereinafter abbreviated as copper loss) are within an appropriate range, thereby ensuring the performance and operating efficiency of the motor. Of these, 865 is an empirical constant, and its specific value depends on the design of the slots and poles in the motor. In this embodiment, the design was mainly performed for a motor with a 12-slot, 8-pole design, so here, the value is set to 865. As shown in the table below, when the motor has a 12-slot, 8-pole design, the relative relationship between the tooth width bt of the stator teeth 111, the inner diameter D of the stator 110, and the residual magnetic flux Br of the permanent magnet 130 shows the effect on iron loss and copper loss.

[0032] [Table 1]

[0033] As shown in the table above, the tooth width bt of the stator teeth 111 is too large, which reduces the area of ​​the stator groove 113, decreases the tooth magnetic flux density of the stator teeth 111, and consequently reduces the iron loss of the motor and increases the copper loss, but increases the total loss and reduces the motor efficiency. Therefore, the tooth width of the stator teeth 111 should be appropriately reduced to improve the tooth magnetic flux density of the stator teeth 111, increase the iron loss, and consequently reduce the copper loss to improve the motor efficiency. Among these, the residual magnetic flux of the permanent magnet 130 is Br, and represents the residual magnetic flux Br of the permanent magnet 130 at 20°C. In one embodiment, the residual magnetic flux Br is close to 1.3T. If the residual magnetic flux Br is too large, both the magnetic flux density in the air gap and the magnetic flux density in the stator teeth 111 and the yoke increase. At this time, the saturation of the silicon steel in the stator teeth 111 intensifies due to the increase in tooth magnetic flux density, not only causing a rapid increase in iron loss and reducing motor efficiency, but also leading to changes in permeance and inductance when the stator teeth 111 become saturated. Under overload conditions, control becomes unstable, and the motor may not operate normally. If the inner diameter D of the stator 110 is too large, and the width bt of the stator teeth 111 does not change as the inner diameter D of the stator 110 increases, the area of ​​the stator groove 113 decreases, the tooth magnetic flux density of the stator teeth 111 decreases, and consequently the iron loss of the motor decreases, copper loss increases, and motor efficiency also decreases.

[0034] Furthermore, the width of the permanent magnet 130 is bM, and the inner diameter of the stator 110 is D, satisfying 0.7 < 4P*bM / (D*π) < 0.78. Specifically, 4P*bM is the sum of the widths of the permanent magnets 130 in the rotor 120, and D*π is the inner circumference of the stator 110. In this embodiment, since the motor adopts a 12-slot 8-pole design, the amount of permanent magnets 130 used can be reduced as much as possible, under the premise of reduced magnetic leakage and a reasonable tooth flux density design, only when the ratio of the sum of the widths of the permanent magnets 130 in the rotor 120 to the inner circumference of the stator 110 is within an appropriate range, thus satisfying 0.7 < 4P*bM / (D*π) < 0.78. This reduces the width of the permanent magnets 130, and consequently reduces the amount of permanent magnets 130 used, thereby reducing material waste and lowering the manufacturing cost of the motor.

[0035] In one embodiment, 4P*bM / (D*π) = 0.75. According to design and continuous testing, when 4P*bM / (D*π) = 0.75, a relatively good magnetic leakage reduction effect can be achieved, allowing for a reasonable tooth magnetic flux density design, reducing the width of the permanent magnet 130, and consequently reducing the amount of permanent magnet 130 used, thereby reducing material waste and lowering the manufacturing cost of the motor.

[0036] In one embodiment, the magnetic barrier groove 122 further extends in a direction away from the d-axis. Specifically, the magnetic barrier groove 122 further extends in a direction away from the d-axis, i.e., the magnetic barrier groove 122 further extends in the direction of the q-axis. The extension of the magnetic barrier groove 122 toward the d-axis may erode the silicon steel space through which the permanent magnet 130 transmits the main magnetic flux to the stator 110. Therefore, to further increase the length of the magnetic shielding bridge and reduce magnetic leakage, the magnetic barrier groove 122 further extends in a direction away from the d-axis. In one embodiment, in order to make the width of the magnetic shielding bridge 123 more uniform and to improve the magnetic shielding effect, the contour of the magnetic barrier region on the side close to the edge of the rotor 120 is provided substantially parallel to the contour of the edge of the rotor 120, and the width of the magnetic shielding bridge 123 may be as equal as possible to the thickness of the perforated sheet of the stator 110, thereby reducing magnetic leakage.

[0037] In one embodiment, the mounting groove 121 includes a first segment 124 and a second segment 125 that are in communication and set at an angle, and the opening at the angle formed by the first segment 124 and the second segment 125 is set away from the axis of the rotor 120, and one permanent magnet 130 is mounted in each of the first segment 124 and the second segment 125. Specifically, the mounting groove 121 includes a first segment 124 and a second segment 125 that are in communication and set at an angle, and the opening at the angle formed by the first segment 124 and the second segment 125 is set away from the axis of the rotor 120, that is, the shape of the mounting groove 121 is approximately V-shaped, and one permanent magnet 130 is mounted in each of the first segment 124 and the second segment 125, thereby improving the magnetic collection effect of the permanent magnet 130 and improving the utilization rate of the permanent magnet 130.

[0038] Furthermore, a demagnetizing region 126 is provided between the first segment 124 and the second segment 125 so that two permanent magnets 130 are provided with a relative gap between them. Specifically, this demagnetizing region 126 can separate the permanent magnets 130, thereby preventing the permanent magnets 130 in the same mounting groove 121 from contacting and interfering with each other, and thereby improving the demagnetizing ability of the permanent magnets 130. In conjunction with the shape of the permanent magnets 130 and the shape of the mounting groove 121, this demagnetizing region 126 takes on a triangular shape overall. In this embodiment, the minimum relative distance between the two permanent magnets 130 is about 0.1 mm.

[0039] In one embodiment, the residual magnetic flux of the permanent magnet 130 is Br, and Br ≥ 1.3T. Specifically, in order to improve the operating stability of the motor and reduce the phenomenon in which the motor becomes unusable due to the loss of residual magnetic flux of the permanent magnet 130, it is required that the residual magnetic flux of the permanent magnet 130 at 20°C be Br. In one embodiment, Br ≥ 1.3T, thereby improving the operating stability of the motor and improving the performance of the motor.

[0040] This application further proposes a compressor which includes a motor, the specific structure of which refers to the above embodiments, and since this compressor adopts all the technical ideas of all the above embodiments, it has at least all the beneficial effects that the technical ideas of the above embodiments bring about, and no further detailed explanation is given here.

[0041] This application further proposes a cooling device which includes a compressor, the specific structure of which refers to the above embodiments, and since this cooling device adopts all the technical ideas of all the above embodiments, it has at least all the beneficial effects that the technical ideas of the above embodiments bring about, and no further detailed explanation is given here.

[0042] The foregoing are merely selectable embodiments of this application and do not limit the scope of this application. Any transformation of equivalent structures created using the contents of the specification and drawings of this application, or any direct or indirect application in other related technical fields, under the inventive concept of this application, are all included within the scope of this application's patent protection. [Explanation of symbols]

[0043] 110 Stator 111 stator teeth 112 Teeth Shoe 113 Stator groove 120 rotors 121 Mounting groove 122 Magnetic barrier groove 123 Magnetic shielding bridge 124 Segment 1 125 Second Segment 126 Demagnetization area 130 Permanent Magnets

Claims

1. A stator comprising a plurality of stator teeth arranged at intervals, wherein the ends of the stator teeth toward the axis of the stator have tooth shoes, A motor comprising a rotor having a plurality of mounting grooves inside, wherein the plurality of mounting grooves are arranged at intervals along the circumferential direction of the rotor, permanent magnets are mounted in the mounting grooves, magnetic barrier grooves are provided at both opposing ends of the mounting grooves, both of the two magnetic barrier grooves extend toward the d-axis, the angle between the connection line between each of the opposing ends of the two magnetic barrier grooves and the center of the rotor is θ1, the angle between the connection line between each of the opposing ends of the tooth shoe and the center of the rotor is θ2, and |θ1 - θ2| < a preset angle.

2. The motor according to claim 1, wherein the preset angle is 2° or less.

3. The motor according to claim 1 or 2, wherein the stator has Q stator teeth, and the rotor has 2P mounting grooves, with Q = 12 and 2P = 8.

4. The motor according to claim 3, wherein the tooth width of the stator teeth is bt, the inner diameter of the stator is D, the residual magnetic flux of the permanent magnet is Br, and |bt - Br * θ1 * D * π / 865| < 0.

5.

5. The motor according to claim 3 or 4, wherein the width of the permanent magnet is bM, the inner diameter of the stator is D, and 0.7 < 4P * bM / (D * π) < 0.

78.

6. The motor according to claim 5, wherein 4P * bM / (D * π) = 0.

75.

7. The motor according to any one of claims 1 to 6, wherein the magnetic barrier groove further extends in a direction away from the d-axis.

8. The motor according to any one of claims 1 to 7, wherein the mounting groove includes a first segment and a second segment that are in communication with each other and are provided at an angle, the opening at the angle formed by the first segment and the second segment is provided away from the axis of the rotor, and one of the permanent magnets is mounted in both the first segment and the second segment.

9. The motor according to claim 8, wherein a demagnetizing region is provided between the first segment and the second segment such that the two permanent magnets are provided with a relative distance between them.

10. The motor according to any one of claims 1 to 9, wherein the residual magnetic flux of the permanent magnet is Br, and Br ≥ 1.3T.

11. A compressor comprising the motor according to any one of claims 1 to 10.

12. A cooling device comprising the compressor described in claim 11.

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