Permanent magnet motor, compressor and refrigeration device

Abstract

This invention discloses a permanent magnet motor, a compressor, and a refrigeration device, relating to the field of motor technology. The permanent magnet motor includes a stator and a rotor. Each group of magnet slots in the circumferential direction of the rotor corresponds to a magnetic pole. Adjacent magnet slots within the same group are separated by an internal magnetic bridge. Magnets are disposed in all magnet slots. The maximum outer diameter of the rotor is D1. The sum of the longest sides of the magnets within the same group is L1, and the minimum side length of any magnet within the same group is L2. The minimum width of the internal magnetic bridge is A1. The minimum distance from the magnet slot to the outer circumference of the rotor is A2. The number of stator slots is Q, and the number of pole pairs of the rotor is P. These parameters are constrained to satisfy corresponding relationships. The technical solution provided by this invention can improve the structural strength of the motor rotor, ensure the reliability of motor operation, promote the wide-frequency development of compressors, and thus accommodate more application fields.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a permanent magnet motor, a compressor, and a refrigeration device. Background Technology

[0002] In the fields of compressors, refrigeration equipment, and home appliances, permanent magnet motors serve as core power components, and their operational stability and wide-frequency adaptability directly affect the performance of end products. As the market demand for wide-frequency compressors (i.e., supporting a wider range of frequency operation) increases, the limitations of traditional permanent magnet motors in high-frequency operation scenarios are becoming increasingly apparent: when traditional motors operate at high frequencies, the rotor is affected by centrifugal force (generated by high-speed rotation) and magnetic pull (generated by the interaction of the stator and rotor magnetic fields), leading to structural deformation, increased vibration, or performance degradation, thus limiting the wide-frequency adaptation of compressors (i.e., adapting to a wider range of operating frequencies). Summary of the Invention

[0003] The main objective of this invention is to propose a permanent magnet motor, compressor, and refrigeration equipment, which aims to improve the structural strength of the motor rotor, ensure the reliability of motor operation, extend the service life of the motor, and help promote the development of wide-frequency compressors, thereby accommodating more application fields.

[0004] To achieve the above objectives, the present invention proposes a permanent magnet motor comprising:

[0005] The stator includes multiple stator slots evenly distributed circumferentially; and

[0006] The rotor is disposed inside the stator. Multiple magnetic slot groups are evenly distributed circumferentially on the rotor, and each magnetic slot group corresponds to a magnetic pole. Each magnetic slot group includes at least two magnetic slots. Adjacent magnetic slots within the same magnetic slot group are separated by an internal magnetic bridge. Magnets are disposed in all magnetic slots.

[0007] Wherein, the maximum outer diameter of the rotor is D1; ​​the sum of the longest sides of the magnets in the same magnet slot group on the rotor cross-section is L1, and the minimum side length of any magnet in the same magnet slot group is L2; ​​the minimum width of the inner magnetic bridge in the same magnet slot group in the direction perpendicular to the rotor radial direction is A1; the minimum distance from the slot wall of the magnet slot away from the rotor center to the outer circumference of the rotor in the same magnet slot group is A2; the number of stator slots is Q, and the number of pole pairs of the rotor is P; satisfying the relationship: 1.5 ≤ ≤2.5, where GCD(Q,P) is the greatest common divisor of Q and P.

[0008] In one embodiment, the axial height of the rotor is H, and the minimum inner diameter of the stator is D2, satisfying the relationship: 21≤ ≤30.

[0009] In one embodiment, the rotor has a shaft hole for drive connection, the minimum inner diameter of the shaft hole being D3, 0.5 ≤ ≤0.9.

[0010] In one implementation, 15 ≤ Q ≤ 18.

[0011] In one implementation, 5 ≤ P ≤ 6.

[0012] In one embodiment, the number of phases of the motor is m, and the number of slots per pole per phase is q, where q = Q / 2mP, and 0 < q < 1.

[0013] In one implementation, 5 ≤ GCD(Q,P) ≤ 6.

[0014] In one embodiment, 0.3mm ≤ A1 ≤ 0.7mm.

[0015] In one embodiment, 50mm ≤ D1 ≤ 90mm.

[0016] The present invention also proposes a compressor, including a permanent magnet motor and a pump body assembly as described above, wherein the pump body assembly includes a crankshaft, and the crankshaft is drivenly coupled to the rotor.

[0017] The present invention also proposes a refrigeration device, including the compressor described above.

[0018] The technical solution of this invention uses the parameter constraint 1.5≤ ≤2.5, balancing structural strength and electromagnetic properties, molecules The effective volume of the magnet and the radial dimension of the rotor are related, affecting the motor's torque output capability; denominator The "structural strength coefficient" reflects the rotor's properties (A1 and A2 affect mechanical strength, while the GCD value of the slot-pole fit affects magnetic field stability). If the ratio is too small (<1.5), the structural strength is excessive but the electromagnetic performance is insufficient (limited torque output); that is, when the relationship is less than 1.5, although the rotor's mechanical strength is greatly improved, as the size of the magnetic bridges (A1 and A2) and the number of unit motors increase, the magnetic leakage will also increase significantly, leading to a decrease in magnet utilization, a decrease in motor efficiency, and thus affecting motor performance. If the ratio is too large (>2.5), the electromagnetic performance is strong but the structural strength is insufficient (prone to deformation at high frequencies); that is, when the relationship is greater than 2.5, the mechanical strength rigidity is insufficient, and at high speeds, the magnetic bridges (A1 and A2) are small, which may break, causing the stator and rotor to seize, and ultimately the compressor to fail. Thus, the above relationship can balance the relationship between centrifugal force and motor cost-effectiveness, achieving optimal motor design and reducing R&D costs and quality fluctuation risks. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the rotor and stator provided by the present invention;

[0021] Figure 2 A schematic diagram of one embodiment of the rotor;

[0022] Figure 3 This is a schematic diagram of another embodiment of the rotor;

[0023] Figure 4 This is a schematic diagram of another embodiment of the rotor;

[0024] Figure 5 This is a schematic diagram of the structure of one embodiment of the stator;

[0025] Figure 6 This is a schematic diagram of the structure of an embodiment of the compressor provided by the present invention;

[0026] Figure 7 A graph showing the relationship between rotor tensile strength and motor efficiency;

[0027] Figure 8 A graph showing the relationship between the rotor magnetic pull and the maximum output torque;

[0028] Figure 9 This is a graph showing the relationship between shaft rigidity and compressor energy efficiency.

[0029] Explanation of icon numbers:

[0030] 100. Stator; 110. Stator slot;

[0031] 200. Rotor;

[0032] 210. Magnet slot assembly; 220. Magnet slot; 230. Inner magnetic bridge; 240. Outer magnetic bridge; 250. Shaft hole; 260. Magnetic isolation bridge;

[0033] 300. Magnet;

[0034] 400. Pump body assembly; 410. Crankshaft.

[0035] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0038] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0039] In the fields of compressors, refrigeration equipment, and home appliances, permanent magnet motors serve as core power components, and their operational stability and wide-frequency adaptability directly affect the performance of end products. As market demand for wider-frequency compressors (i.e., supporting a broader frequency range of operation) increases, the limitations of traditional permanent magnet motors in high-frequency operating scenarios are becoming increasingly apparent.

[0040] When traditional motors operate at high frequencies, the rotor is affected by centrifugal force (generated by high-speed rotation) and magnetic pull (generated by the interaction of the stator and rotor magnetic fields), which leads to structural deformation, increased vibration, or performance degradation, thus limiting the wide-frequency operation of compressors (i.e., adapting to a wider range of operating frequencies).

[0041] The aforementioned problems collectively limit the stable operation of motors in the high-frequency range, failing to meet the comprehensive requirements of wide-range compressors for "high rigidity, low interference, and wide operating range." Therefore, there is an urgent need for a permanent magnet motor design scheme that optimizes the constraints of key rotor structure parameters to simultaneously improve mechanical strength and electromagnetic performance, thereby promoting the development of wide-range compressors.

[0042] Specifically, during high-frequency operation, the high-speed rotation of the rotor generates significant centrifugal force. If the rotor structure lacks rigidity (e.g., the magnetic bridge between the magnet slots is too narrow, or the distance from the magnet slot to the outer circumference is too small), it can easily lead to deformation or even cracking of the rotor core, affecting mechanical reliability. On the other hand, the interaction of the magnetic fields of the stator and rotor generates magnetic pull fluctuations. If the number of stator slots and the number of rotor pole pairs are not properly matched, it will exacerbate harmonic interference, causing vibration and noise. Because in traditional single-magnet structures (one slot per pole), the centrifugal force is concentrated in the middle of the magnet during high-speed operation, causing magnet displacement or even breakage, thus limiting the rotational speed. Secondly, if the magnet size is increased to improve the magnetic flux (e.g., widening the circumferential length L1 of the magnet), the mechanical strength of the rotor must be sacrificed; while reducing the width of the inner magnetic bridge A1 will reduce the bending stiffness (making centrifugal deformation more likely); and reducing the distance from the outer wall of the magnetic slot A2 will lead to the risk of tearing of the rotor outer circumference, which can easily cause high-frequency resonance and generate additional vibration and noise.

[0043] To address this, the present invention proposes a permanent magnet motor that improves rotor rigidity by constraining key parameters of the rotor structure, effectively reducing the influence of centrifugal force and magnetic pull during high-frequency operation, meeting customer market demands, and creating a wide-frequency compressor.

[0044] Please see Figures 1 to 5 In one embodiment of the present invention, the permanent magnet motor includes a stator 100 and a rotor 200.

[0045] The stator 100 includes a plurality of stator slots 110 evenly distributed circumferentially; the rotor 200 is disposed inside the stator 100, and the rotor 200 has a plurality of magnetic slot groups 210 evenly distributed circumferentially, each magnetic slot group 210 corresponding to a magnetic pole; each magnetic slot group 210 includes at least two independent magnetic slots 220; adjacent magnetic slots 220 within the same magnetic slot group 210 are separated by an inner magnetic bridge 230; all magnetic slots 220 are provided with magnets 300; wherein, the maximum outer diameter of the rotor 200 is D1; ​​the same magnetic slot group 210... The sum of the longest sides of the magnets 300 within the same magnetic slot group 210 on the cross-section of the rotor 200 is L1; the minimum side length of any magnet 300 within the same magnetic slot group 210 is L2; ​​the minimum width of the inner magnetic bridge 230 within the same magnetic slot group 210 in the direction perpendicular to the radial direction of the rotor 200 is A1; the minimum distance from the slot wall of the magnetic slot 220 in the same magnetic slot group 210 away from the center of the rotor 200 to the outer circumference of the rotor 200 is A2; the number of stator slots 110 is Q; the number of pole pairs of the rotor 200 is P; satisfying the relationship: 1.5 ≤ ≤2.5, where GCD(Q,P) is the greatest common divisor of Q and P.

[0046] Reference Figure 1 and Figure 5Specifically, the stator 100 is composed of a stator core (including a yoke and teeth) and stator windings. The yoke is a ring structure that provides a closed magnetic circuit path. The teeth are distributed circumferentially along the yoke and together with the yoke define the stator slots 110 for placing the stator windings. When the stator windings are energized, they generate a rotating magnetic field, which interacts with the magnetic field of the rotor 200 to drive the motor.

[0047] Reference Figures 1 to 4 The rotor 200 consists of a rotor core (equipped with magnetic slots 220, inner magnetic bridges 230, and outer magnetic bridges 240) and magnets 300. The magnetic slots 220 are evenly distributed along the outer circumference of the rotor 200. Several magnetic slots 220 form magnetic slot groups 210 (two, three, or more). Each magnetic slot group 210 forms a magnetic pole (multi-slot design can optimize the magnetic field distribution). For example, two magnetic slot groups 210 are arranged in a V-shape or a straight line; or three magnetic slot groups 210 are arranged in a U-shape, etc. Each magnetic pole is separated into at least two independent magnetic slots 220 by the inner magnetic bridge 230. The minimum width (A1) of the inner magnetic bridge 230 and the minimum distance (A2) from the magnetic slot 220 to the outer circumference of the rotor 200 form a rigid support structure, which can directly resist the centrifugal force load during high-frequency rotation. Compared to the traditional single-magnet slot 220 design, the distributed layout of the internal magnetic bridge 230 avoids stress concentration and reduces the risk of rotor core cracking.

[0048] Reference Figure 1 , Figure 2 and Figure 4 The sum of the longest sides of the magnets 300 within the same magnet slot group 210 on the cross-section of the rotor 200 is L1. That is, if there are two magnets 300 in the same magnet slot group 210, and the longest sides of the two magnets 300 are a and b respectively, then L1 = a + b. (Refer to...) Figure 3 Similarly, if a magnetic steel trough group 210 includes three magnets 300, and the longest side of each of the three magnets 300 is a, b and c, then L1 = a + b + c.

[0049] Reference Figures 1 to 4 Multiple magnetic slots 220 within the same magnetic slot group 210 are not connected to each other. Adjacent magnetic slots 220 are separated by an inner magnetic bridge 230 (reinforcing rib) (to improve the radial strength of the rotor 200 and resist centrifugal force). Magnetic slots 220 between different magnetic poles are separated by a magnetic isolation bridge 260 (to reduce magnetic leakage and improve magnetic circuit efficiency). In other words, adjacent magnetic slots 220 within adjacent magnetic slot groups 210 are not connected. A magnet 300 is placed inside each magnetic slot 220, interacting with the stator magnetic field to generate torque.

[0050] The distance from the wall of the magnetic slot 220 in the same magnetic slot group 210 away from the center of the rotor 200 to the outer circle of the rotor 200 is also called the outer magnetic bridge 240, and the minimum size of the outer magnetic bridge 240 is A2.

[0051] In this embodiment, a permanent magnet motor is used in a rotary rotor 200 compressor. The rotor core has an inner circle that cooperates with the crankshaft 410 of the pump body assembly 400 in the compressor to transmit torque to the pump body (crankshaft 410, bearing, cylinder).

[0052] The technical solution of this invention uses the parameter constraint 1.5≤ ≤2.5, balancing structural strength and electromagnetic properties, refer to Figure 1 , Figure 2 and Figure 4 The sum of the longest sides of the magnets 300 within the same magnet slot group 210 on the cross-section of the rotor 200 is L1. That is, if there are two magnets 300 in the same magnet slot group 210, and the longest sides of the two magnets 300 are a and b respectively, then L1 = a + b. (Refer to...) Figure 3 Similarly, if there are three magnets 300, and the longest sides of each magnet 300 are a, b and c, then L1 = a + b + c.

[0053] Reference Figures 1 to 4 Multiple magnetic slots 220 within the same magnetic slot group 210 are not connected to each other. Adjacent magnetic slots 220 are separated by an inner magnetic bridge 230 (reinforcing rib) (to improve the radial strength of the rotor 200 and resist centrifugal force). Magnetic slots 220 between different magnetic poles are separated by a magnetic isolation bridge 260 (to reduce magnetic leakage and improve magnetic circuit efficiency). In other words, adjacent magnetic slots 220 within adjacent magnetic slot groups 210 are not connected. A magnet 300 is placed inside each magnetic slot 220, interacting with the stator magnetic field to generate torque.

[0054] The distance from the wall of the magnetic slot in the same magnetic slot group 210 away from the center of the rotor 200 to the outer circle of the rotor 200 is also called the outer magnetic bridge 240, and the minimum size of the outer magnetic bridge 240 is A2.

[0055] In this embodiment, a permanent magnet motor is used in a rotary rotor 200 compressor. The rotor core has an inner circle that cooperates with the crankshaft 410 of the pump body assembly 400 in the compressor to transmit torque to the pump body (crankshaft 410, bearing, cylinder).

[0056] molecular The effective volume of the magnet and the radial dimension of the rotor are related, affecting the motor's torque output capability; denominator The "structural strength coefficient" reflects the rotor (A1 and A2 affect mechanical strength, and the GCD value of slot pole matching affects magnetic field stability).

[0057] Specifically, in rotary compressors, the main consideration is the impact of centrifugal force on the mechanical strength of rotor 200 during operation. For rotor 200, the larger the outer diameter D1 of the rotor core, the greater the linear velocity of the outer circle during operation, thus requiring higher mechanical strength from rotor 200. The permanent magnet motor adopts an internal magnetic circuit structure, with magnet 300 located within the magnetic slot 220. The larger the dimensions L1 and L2 of magnet 300, the greater the stress on the outer side of the rotor core, thereby affecting the rigidity of rotor 200. The rotor magnetic bridge (A1 (minimum distance of inner magnetic bridge 230) and A2 (distance from magnetic slot 220 to outer circle)) improves the mechanical strength of rotor 200. Furthermore, as the number of unit motors increases, rotor 200 becomes more stable during operation, and the amplitude of rotor 200 fluctuations and sway will decrease accordingly, contributing to stable operation of rotor 200.

[0058] Reference Figure 7 In the curve showing the relationship between rotor tensile strength and motor efficiency, the graph includes two curves, representing the changes in rotor tensile strength and motor efficiency as a function of... The changes in this variable are as follows: The rotor tensile strength curve generally shows a trend of first rising and then falling, while the motor efficiency curve generally shows a trend of first falling and then rising. Figure 7 As can be seen, when the relationship is less than 1.5, although the mechanical strength of the rotor is greatly improved, the magnetic leakage also increases significantly with the increase of the magnetic bridge width and the number of unit motors, resulting in a decrease in magnet utilization, motor efficiency, and thus affecting motor performance. When the relationship is greater than 2.5, the mechanical strength and rigidity are insufficient. During high-speed operation, the magnetic bridge may break, causing the stator and rotor to seize up, leading to compressor failure.

[0059] Therefore, this formula can balance the relationship between centrifugal force and the cost-effectiveness of the motor, achieving optimal motor design. Specifically, this scheme quantifies the ratio of "electromagnetic performance" to "structural strength" through a formula (constrained at 1.5~2.5), providing a clear basis for parameter selection in the design:

[0060] If the ratio is too small (<1.5), the structural strength is excessive but the electromagnetic performance is insufficient (torque output is limited); that is, when the relationship is less than 1.5, although the mechanical strength of the rotor is greatly improved, as the size of the magnetic bridge (A1 and A2) and the number of unit motors increase, the magnetic leakage will also increase significantly, resulting in a decrease in the utilization rate of the magnet, a decrease in motor efficiency, and thus affecting the motor performance.

[0061] If the ratio is too large (>2.5), the electromagnetic performance is strong but the structural strength is insufficient (it is easy to deform at high frequencies); that is, when the relationship is greater than 2.5, the mechanical strength and rigidity are insufficient. When running at high speed, the magnetic bridge (A1 and A2) is small in size and may break, causing the stator and rotor to jam, and thus the compressor will fail.

[0062] Thus, the above relationship can be used to balance the relationship between centrifugal force and the cost-effectiveness of the motor, achieving optimal motor design. Specifically, in traditional motor design, the balance between electromagnetic performance and structural strength relies on trial and error based on experience, lacking clear quantitative standards. However, by constraining the relevant parameters within a reasonable range, "high rigidity, low interference, and wide-frequency operation" can be achieved. This eliminates the need for repeated iterative verification, allowing the optimal solution to be quickly locked in by adjusting parameters such as D1, L1, L2, A1, and A2. This ensures that motor products of different batches and specifications can meet the unified performance standards of wide-frequency compressors, reducing R&D costs and the risk of quality fluctuations.

[0063] Combination Figure 6 Furthermore, the rotor 200 includes a rotor core with an axial height of H, and the stator 100 includes a stator core with a minimum inner diameter of D2, satisfying the relationship: 21 ≤ ≤30. In rotary compressors, the influence of magnetic pull on the rigidity of rotor 200 during operation needs to be considered. The larger the number of pole pairs P of rotor 200, the higher the magnetic load of the motor, and the higher the radial magnetic pull. The total radial magnetic pull is the stress integral force on the air gap surface. Therefore, the larger the outer diameter D1 of rotor 200 and the height H of rotor core, the larger the air gap surface area, and the higher the radial magnetic pull. The armature of stator 100 and the magnetic field of rotor 200 interact in the air gap. Therefore, the larger the air gap length (D2-D1) / 2, the smaller the interacting radial magnetic pull, thereby reducing deformation.

[0064] Reference Figure 8 In the curves showing the relationship between rotor magnetic pull and maximum output torque, the rotor magnetic pull generally shows a decreasing trend, decreasing rapidly in the early stage and then stabilizing. The maximum output torque generally shows an increasing trend, increasing rapidly in the early stage and then stabilizing. When the relationship is less than 21, the radial magnetic pull of the motor is small, ensuring that the magnetic pull does not affect shaft deformation. However, the rotor magnetic load, the rotor air gap surface area, or the air gap length decreases, leading to a decrease in the motor's maximum output torque capacity. When the relationship is greater than 30, the rotor volume is large, the magnetic load is high, and the air gap length is small, resulting in a high magnetic pull. This increases the impact of the radial magnetic pull on the rigid deformation of the shaft, severely causing shaft deformation, pump body component wear, and stator and rotor rubbing.

[0065] Measurement of the dimensions of each parameter.

[0066] The starting / ending point of the maximum outer diameter D1 of rotor 200 is determined using the effective cylindrical surface of the rotor core as a reference (ignoring undesigned defects). Four evenly distributed points (0°, 90°, 180°, 270°) are taken along the circumferential direction on the end faces of both ends of the rotor core. The diameter of all measured points is recorded, and the maximum value is taken as D1. If there are undesigned pits / protrusions (such as dents caused by impacts), measurement points must be reselected outside the defect area. If the outer edge of rotor 200 has grooves, the groove area is avoided during measurement, and only the diameter of the complete cylindrical surface is taken.

[0067] The side length of magnet 300 is the geometric dimension of magnet 300 within the magnetic slot 220 on the cross-section (perpendicular to the axial direction) of rotor 200. In the cross-section, magnet 300 is rectangular with a long side and a short side. The length of the magnet 300's outline is measured using tools such as vernier calipers. If there are two magnets 300 in the same magnetic slot 220, the longest side of each magnet 300 is measured on the cross-section, assuming it to be a and b, then L1 = a + b. If the shortest side values ​​of the two magnets 300 are different, the average value is taken. If magnet 300 has a slight chamfer on its edge (due to process requirements), the chamfer is ignored, and the side length of the main body is measured.

[0068] The minimum width (A1) of the inner magnetic bridge 230 is the minimum distance between adjacent magnetic slots 220 within the same magnetic slot group 210, perpendicular to the radial direction of the rotor 200 (i.e., the narrowest width of the magnetic bridge). Using calipers or other tools, find the narrowest position of the inner magnetic bridge 230 on the cross-section of the rotor 200. Taking the inner wall edges of the two magnetic slots 220 as the starting and ending points, measure the distance perpendicular to the extension direction of the magnetic bridge. Take the measurements from three different cross-sections, and take the minimum value as A1. If the magnetic bridge has machining marks or local depressions, use the design theoretical contour line as the reference.

[0069] The minimum distance (A2) from the magnet slot 220 to the outer circle is the shortest radial distance from the slot wall (outer slot wall) of the magnet slot 220 away from the center of the rotor 200 to the outer circle contour of the rotor 200. A polar coordinate system is established with the center of the rotor 200 as the origin. The radial distance from each point on the outer slot wall to the outer circle contour is measured. The minimum value is A2. If a local bulge on the outer circle causes the distance to be smaller (not in line with design requirements), then that point is not included, and the minimum value of the remaining area is taken.

[0070] The axial height (H) of rotor 200 is the effective height of rotor 200 along the axial direction. Using both end faces as references, ignoring non-functional axial grooves (such as keyways and weight-reducing holes), and using the two end planes of the rotor core as reference planes (if the end faces have chamfers, the plane containing the chamfer root is used), the distance between the two reference planes is measured axially. Heights are measured at three evenly spaced points circumferentially, and the average value is taken as H. If the design incorporates an internal stepped structure (such as a shoulder), only the height of the core portion is measured (excluding the shoulder).

[0071] The minimum inner diameter (D2) of the stator core is the minimum diameter of the inner circle of stator 100, excluding internal structures such as slots. Four evenly distributed points are selected at both ends of the stator 100 along the axial direction, avoiding slots, to measure the inner diameter. All measured values ​​are recorded, and the minimum value is taken as D2.

[0072] Furthermore, the rotor core has a shaft hole 250 for transmission connection, the minimum inner diameter of the shaft hole 250 being D3, 0.5≤ ≤0.9. This formula is dimensionless, substituting the numerical values ​​(based on the specified units) of all physical quantities (D3, D1, H) into the formula, and the units in the formula are ignored. When substituting all quantities, only their numerical values ​​are used, that is, only numerical calculations are performed.

[0073] In a rotary compressor, the crankshaft 410 in the pump body assembly 400 is connected to the shaft hole 250 of the rotor 200. When the shaft hole 250 of the rotor core is larger, that is, when D3 is larger, the shaft diameter of the crankshaft 410 is also larger, and the resistance to deformation is stronger. That is, the minimum inner diameter D3 of the shaft hole 250 (the diameter of the hole at the center of the rotor used to install the output shaft, which must meet the strength requirements of interference fit or key connection with the external transmission shaft). When the outer diameter D1 of the rotor 200 is larger, the centrifugal force of the rotor 200 during operation is greater, and the risk of deformation of the pump body shaft system is also greater. Since the rotary compressor is a single cantilever beam structure, when the axial height H of the rotor core is larger, the amplitude of the swing away from the bearing end is also larger, and the risk of stator and rotor rubbing increases. When the greatest common divisor GCD(Q,P) of the number of poles and the number of slots is larger, that is, the number of unit motors increases, the magnetic load increases, the radial magnetic pull increases accordingly, and thus affects the deformation of the shaft system.

[0074] Reference Figure 9 In the curve showing the relationship between shaft rigidity and compressor energy efficiency, shaft rigidity generally shows an upward trend, while compressor energy efficiency generally shows a downward trend. When the relationship is less than 0.5, the pump body shaft rigidity is insufficient, and its ability to resist the effects of centrifugal force and magnetic pull does not meet the actual operating requirements. When the relationship is greater than 0.9, increasing the crankshaft outer diameter can improve shaft rigidity, but the larger the crankshaft outer diameter, the greater the pump body frictional mechanical loss, and the greater the decrease in energy efficiency.

[0075] Specifically, the units for L1, L2, H, D1, D2, D3, A1, and A2 are mm.

[0076] Specifically, 15≤Q≤18, such as 15, 16, 17, 18.

[0077] Specifically, 5≤P≤6, such as 5 and 6.

[0078] By limiting 15≤Q≤18 and 5≤P≤6, the protection range is further restricted to specific pole-slot combinations of "15 / 16 / 17 / 18 slots, 10 or 12 poles". In this case, the value range of GCD(Q,P) can be uniquely determined. For example, the motor has 15 slots and 10 poles, or 18 slots and 12 poles.

[0079] Specifically, 5 ≤ GCD(Q,P) ≤ 6.

[0080] To balance production cycle time and winding equipment capacity, a motor design with a fractional number of slots per pole and per phase is required. Simultaneously, considering the need to reduce noise and vibration in multi-slot motors, the fractional-slot harmonic suppression characteristics are utilized to balance vibration resistance and weight reduction. Specifically, the motor has m phases and q slots per pole and per phase, where q = Q / 2mP, and 0 < q < 1. The motor uses fractional-slot concentrated windings (e.g., q = 0.25, 0.5, etc.) rather than integer-slot distributed windings.

[0081] For the purpose of optimizing material costs and lightweighting, specifically, 0.3mm≤A1≤0.7mm, and specifically, 50mm≤D1≤90mm.

[0082] The present invention also proposes a compressor, which includes a permanent magnet motor and a pump assembly 400. The specific structure of the permanent magnet motor is as described in the above embodiments. Since this compressor adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here. The pump assembly 400 includes a crankshaft 410, which is driven by a rotor 200.

[0083] The pump body assembly 400 also includes a cylinder and a piston that is rotated and compressed within the cylinder. The piston is connected to the rotor 200 via a crankshaft 410 so as to drive the piston to rotate eccentrically as the rotor 200 rotates.

[0084] The present invention also proposes a refrigeration device, including the compressor described above.

[0085] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A permanent magnet motor, characterized in that, include: The stator includes multiple stator slots evenly distributed along the circumference; and The rotor is disposed inside the stator. Multiple magnetic slot groups are evenly distributed circumferentially on the rotor, and each magnetic slot group corresponds to a magnetic pole. Each magnetic slot group includes at least two magnetic slots. Adjacent magnetic slots within the same magnetic slot group are separated by an internal magnetic bridge. Magnets are disposed in all magnetic slots. Wherein, the maximum outer diameter of the rotor is D1; ​​the sum of the longest sides of the magnets in the same magnet slot group on the rotor cross-section is L1, and the minimum side length of any magnet in the same magnet slot group is L2; ​​the minimum width of the inner magnetic bridge in the same magnet slot group in the direction perpendicular to the rotor radial direction is A1; the minimum distance from the slot wall of the magnet slot away from the rotor center to the outer circumference of the rotor in the same magnet slot group is A2; the number of stator slots is Q, and the number of pole pairs of the rotor is P; satisfying the relationship: 1.5 ≤ ≤2.5, where GCD(Q,P) is the greatest common divisor of Q and P.

2. The permanent magnet motor as described in claim 1, characterized in that, The axial height of the rotor is H, and the minimum inner diameter of the stator is D2, satisfying the relationship: 21≤ ≤30.

3. The permanent magnet motor as described in claim 2, characterized in that, The rotor has a shaft hole for transmission connection, the minimum inner diameter of the shaft hole being D3, 0.5≤ ≤0.

9.

4. The permanent magnet motor as described in any one of claims 1 to 3, characterized in that, 15≤Q≤18。 5. The permanent magnet motor as described in any one of claims 1 to 3, characterized in that, 5≤P≤6。 6. The permanent magnet motor as described in any one of claims 1 to 3, characterized in that, The motor has m phases and q slots per pole per phase, where q = Q / 2mP, and 0 < q < 1.

7. The permanent magnet motor as described in any one of claims 1 to 3, characterized in that, 5≤GCD(Q,P)≤6.

8. The permanent magnet motor as described in any one of claims 1 to 3, characterized in that, 0.3mm≤A1≤0.7mm.

9. The permanent magnet motor as described in any one of claims 1 to 3, characterized in that, 50mm≤D1≤90mm.

10. A compressor, characterized in that, The invention includes a permanent magnet motor and a pump body assembly as described in any one of claims 1 to 9, wherein the pump body assembly includes a crankshaft that is driven in conjunction with the rotor.

11. A refrigeration device, characterized in that, Includes the compressor as described in claim 10.

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