Rotor structure, motor and compressor

Abstract

The invention provides a rotor structure, a motor and a compressor, relates to the technical field of compressors, and solves the technical problem that the motor is poor in demagnetization resistance. The rotor structure comprises a magnetic baffle plate, a rotor iron core and a permanent magnet, the rotor core is uniformly provided with a plurality of permanent magnet grooves along the circumferential direction. The permanent magnets are embedded in the permanent magnet grooves; the magnetic baffle is arranged at the top of the rotor core; magnetic isolation air grooves are formed in the tail ends of the permanent magnet grooves; the permanent magnet has a first end face and a second end face. The second end face is a plane, and the first end face is of a V-shaped inclined face or arc face structure with the middle concave and the two protruding ends. By optimizing the permanent magnet thickening at the two ends of the end face shape of the permanent magnet and the design of the magnetic isolation air grooves, the easily demagnetized area is improved, the demagnetization risk is effectively reduced, the magnetic leakage at the end of the permanent magnet is reduced by optimizing the magnetic isolation bridge structure, the utilization rate of the permanent magnet is improved, the overall performance and stability of the motor are improved, and long-term efficient operation of the system is ensured.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a rotor structure, a motor, and a compressor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) use permanent magnets for excitation, offering advantages in high power density and low cost. Most variable frequency compressor motors utilize PMSMs. To develop more cost-effective models, current motor research leans towards high-speed, miniaturized, and high-power-density designs. Smaller motors used in heavy-load conditions require rotors with greater load capacity, but this increases the risk of motor demagnetization. During operation, under harsh conditions, the compressor may become unstable, leading to frequent motor starts or start-ups. In such situations, the inverter generates a large instantaneous current. Since the compressor's internal airflow is high-pressure and high-temperature, sufficiently high temperature and current can cause irreversible motor demagnetization. Demagnetization of the permanent magnets reduces motor performance, potentially causing system malfunction. Therefore, research into demagnetization resistance in PMSMs is necessary to improve motor reliability. Summary of the Invention

[0003] The purpose of this invention is to provide a rotor structure, a motor, and a compressor to solve the technical problem of poor anti-demagnetization ability of motors in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a rotor structure, including a magnetic baffle plate, a rotor core, and permanent magnets; the rotor core is uniformly provided with a plurality of permanent magnet slots along its circumference; the permanent magnets are embedded in the permanent magnet slots; the magnetic baffle plate is arranged on the top of the rotor core; a magnetic isolation air slot is provided at the end of each permanent magnet slot; the permanent magnet has a first end face and a second end face; the second end face of the permanent magnet is a plane, and the first end face of the permanent magnet is a V-shaped inclined surface or arc surface structure with a concave middle and convex ends.

[0005] External factors contributing to motor demagnetization: 1. Permanent magnet synchronous motors are used in air conditioning compressors, where the internal airflow is high-pressure, high-temperature gas; 2. The reverse instantaneous current experienced by the motor during startup. To improve motor efficiency, this invention provides a rotor structure that optimizes the end face shape of the permanent magnets, thickens the permanent magnets at both ends, and designs magnetic isolation air slots (thinning the magnetic isolation bridge architecture). This improves the easily demagnetized areas, effectively reduces the risk of demagnetization, and reduces magnetic leakage at the ends of the permanent magnets by optimizing the magnetic isolation bridge architecture. This improves the utilization rate of the permanent magnets, enhances the overall performance and stability of the motor, and ensures long-term efficient operation of the system.

[0006] As a further improvement of the present invention, the permanent magnet is provided with rounded chamfer structures R at all four corners along its length (rotor core axial direction), and the radius a of the rounded chamfer structure R should satisfy: 0.3 < 2a < T, where T is the thickness at the widest point of the permanent magnet, which improves the magnetic focusing effect at the inflection point, and at the same time increases the magnetic resistance of the demagnetizing magnetic circuit at the outer end of the permanent magnet in this region, thereby reducing the demagnetizing effect.

[0007] The magnetic field is concentrated at the edges and corners of permanent magnets, making them more prone to demagnetization under reverse forces. This leads to magnetic distortion at the sharp corners of the permanent magnets. To reduce the presence of sharp edges and corners, and to reduce local magnetic field concentration, rounded corners are designed. This increases the magnetic resistance of the demagnetizing magnetic circuit at the outer end of the permanent magnet, improving its demagnetization resistance. It also reduces the presence of sharp edges and corners, avoids magnetic field distortion caused by sharp corners, improves the magnetic concentration effect at inflection points, and solves the problem of poor demagnetization resistance in permanent magnet motors. The inherent material properties of permanent magnets mean that they will demagnetize under high temperature and high current. Permanent magnets have corresponding weak points for demagnetization, concentrated at the edges and corners. By widening and thickening these areas, the demagnetization resistance can be improved.

[0008] As a further improvement of the present invention, two adjacent permanent magnets are arranged in a V-shape to form rotor magnetic poles; the included angle β of the rotor magnetic poles is in the range of 90°≤β≤130°. The smaller the included angle, the deeper the permanent magnet sinks, and the smaller the area of ​​the high-density magnetic field lines between the permanent magnet and the rotor magnetic isolation bridge. Under the action of the demagnetizing magnetic field, the area of ​​the permanent magnet that is prone to demagnetization is reduced, thereby improving the overall demagnetization resistance of the motor.

[0009] The second end face of the permanent magnet is a plane, and the magnetization direction of the permanent magnet is perpendicular to the second end face. The first rotor magnetic pole and the second rotor magnetic pole are magnetized in the same direction and are built into the rotor core, exhibiting the same polarity, becoming the S pole or N pole in the rotor magnetic pole. In the rotor core, the S pole and N pole are alternately distributed.

[0010] As a further improvement of the present invention, the thickness difference Δt between the end thickness T and the center thickness t of the permanent magnet satisfies the following relationship: 0 < Δt < t / 6. Specifically, the permanent magnet gradually thickens towards both ends symmetrically from the center of the first end face facing the outside of the rotor. The first end face of the permanent magnet has an arc-shaped structure, with the maximum thickness at both ends being T and the minimum thickness at the center being t.

[0011] As a further improvement of the present invention, the first end face of the permanent magnet is a full circular arc structure, and the radius R1 of the arc corresponding to the first end face of the permanent magnet satisfies the following relationship: R1=(k 2 +△t 2) / 2△t, where k is half the width of the permanent magnet; or; the first end face of the permanent magnet includes a straight section and arc segments located on both sides of the straight section; the radius R0 of the arc segment satisfies the following relationship: R0=(K 2 +K0 2 -2KK0+4△t 2 ) / 8△t; where K0 is the width of the straight section and K is the width of the permanent magnet.

[0012] As a further improvement of the present invention, the distance between the edge of the permanent magnet and the sidewall of the permanent magnet is no greater than 0.05 mm. Specifically, the first end face and the second end face of the permanent magnet slot correspond to the first and second end faces of the permanent magnet. In order to improve the utilization rate of the permanent magnet magnetic field and shorten the distance of the air along the direction of the magnetic field lines, the single-sided distance between the permanent magnet and the permanent magnet slot is controlled to be less than 0.05 mm.

[0013] As a further improvement of the present invention, the magnetically shielding air slot includes a first air slot and a second air slot; the first air slot is formed on the permanent magnet slot near the outer circle of the rotor core and extends towards another permanent magnet slot in the same rotor pole; the second air slot is formed on the permanent magnet slot near the center of the rotor core (near the d-axis end) and communicates with another second air slot in the same rotor pole. The specific dimensions and areas of the first and second air slots are not required.

[0014] The rotor has two first air slots and one second air slot with the same polarity. The air slots are connected to the permanent magnet slots. The magnetic permeability of air is much smaller than that of the silicon steel sheet material of the rotor core. The magnetic field lines of the permanent magnet are relatively dense in the region near the outer side of the rotor and in the d-axis direction. When there is a reverse instantaneous current, these two regions of the permanent magnet are greatly affected and have a greater risk of demagnetization. Therefore, air slots are set in these two regions. By opening air slots around the easily demagnetized parts of the permanent magnet, the magnetic resistance of the region is increased, the demagnetizing magnetic field in the region is weakened, the magnetic flux density of the permanent magnet in the region is reduced, and the occurrence of irreversible demagnetization of the permanent magnet is reduced.

[0015] As a further improvement of the present invention, the first air slot and the outer circle of the rotor core are concentric circles; a magnetic isolation bridge is formed between the outer edge of the first air slot and the outer edge of the rotor core, and the thickness of the magnetic isolation bridge is 0.3mm-0.6mm. In order to reduce magnetic leakage at the end of the permanent magnet, improve the utilization rate of the permanent magnet, and improve the efficiency of the motor, the thickness of the magnetic isolation structure is very thin, with a design thickness of 0.3mm to 0.6mm.

[0016] As a further improvement of the present invention, the magnetic baffle is a circular ring structure with a diameter smaller than the inner diameter of the first air groove and an inner ring diameter larger than the outer diameter of the second air groove. The function of the rotor magnetic baffle is to block the permanent magnet and prevent it from flying out during rotor rotation. The rotor magnetic baffle is required not to cover the first and second air grooves, and airflow should pass through the air grooves to reduce the thermal demagnetization effect caused by excessively high heating temperature of the permanent magnet.

[0017] The present invention provides an electric motor, including the rotor structure.

[0018] The present invention provides a compressor, including the motor. 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 these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the rotor core structure in the rotor structure of the present invention; Figure 2 This is a schematic diagram of the magnetic baffle plate in the rotor structure of the present invention; Figure 3 This is a schematic diagram of the rotor structure of the present invention; Figure 4 This is a schematic diagram of the structure of the permanent magnet in the rotor structure of the present invention, representing the first embodiment. Figure 5 This is a schematic diagram of the second embodiment of the permanent magnet in the rotor structure of the present invention; Figure 6 This is a magnetic density cloud diagram of the permanent magnet in the rotor structure of the present invention after demagnetization; Figure 7 yes Figure 1 Enlarged view of part A in the middle.

[0021] In the picture: 1. The first permanent magnet; 2. Second permanent magnet; 3. Rotor core; 4. Magnetic baffle; 5. First end face of the permanent magnet slot; 6. Second end face of the permanent magnet slot; 7. First air tank; 8. Second air tank; 9. Magnetic bridge; 10. The first end face of the permanent magnet; 11. Second end face of permanent magnet. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] Example 1: like Figure 1 As shown, the present invention provides a rotor structure, including a magnetic baffle plate 4, a rotor core 3, and permanent magnets; the rotor core 3 is uniformly provided with a plurality of permanent magnet slots along the circumference; the permanent magnet slots have two opposite large end faces, namely the first end face 5 and the second end face 6 of the permanent magnet slot; the permanent magnets are embedded in the permanent magnet slots; the magnetic baffle plate 4 is arranged on the top of the rotor core 3; and a magnetic shielding air slot is provided at the end of the permanent magnet slot.

[0024] It should be noted that the permanent magnet also has two relatively large end faces, namely: the first end face 10 of the permanent magnet and the second end face 11 of the permanent magnet; the first end face 10 of the permanent magnet and the first end face 5 of the permanent magnet groove are correspondingly arranged, and the second end face 11 of the permanent magnet and the second end face 6 of the permanent magnet groove are correspondingly arranged, and their shapes are compatible; in this embodiment, as Figure 4 As shown in Figure 5, the permanent magnet is thickened in areas prone to demagnetization. Since abrupt changes in the thickness of the permanent magnet structure can cause magnetic distortion in the abrupt region, the second end face 11 of the permanent magnet is a plane, and the first end face 10 of the permanent magnet is a V-shaped inclined or arc-shaped structure with a concave middle and convex ends. This structure makes the two ends of the permanent magnet thicker and the middle thinner, with the thickness of the permanent magnet center being t and gradually increasing to T from the two ends.

[0025] External factors causing motor demagnetization include: 1. Permanent magnet synchronous motors are used in air conditioning compressors, where the internal airflow is high-pressure, high-temperature gas; 2. The reverse instantaneous current experienced by the motor during startup.

[0026] like Figure 6 As shown, in order to improve motor efficiency, the present invention provides a rotor structure that improves the demagnetization area and effectively reduces the risk of demagnetization by optimizing the end face shape of the permanent magnet, thickening the permanent magnets at both ends and designing the magnetic isolation air groove (thinning magnetic isolation bridge 9 architecture). By optimizing the magnetic isolation bridge 9 architecture, the leakage magnetic flux at the end of the permanent magnet is reduced, thereby improving the utilization rate of the permanent magnet, enhancing the overall performance and stability of the motor, and ensuring the long-term efficient operation of the system.

[0027] like Figure 4 or Figure 5As shown, as a further improvement of the present invention, the four corners (the four sides between the four adjacent planes, a total of four sides) of the permanent magnet along the length direction (axial direction of the rotor core 3) are provided with rounded chamfer structures R, and the radius a of the rounded chamfer structure R should satisfy: 0.3 < 2a < T, where T is the thickness at the widest point of the permanent magnet. Through this structural improvement, the magnetic focusing effect at the inflection point is improved, and the magnetic resistance of the demagnetizing magnetic circuit at the outer end of the permanent magnet in this region is increased, thereby reducing the demagnetizing effect.

[0028] The magnetic field is concentrated at the edges and corners of permanent magnets, making them more prone to demagnetization under reverse forces. This leads to magnetic distortion at the sharp corners of the permanent magnets. To reduce the presence of sharp edges and corners, and to reduce local magnetic field concentration, rounded corners are designed. This increases the magnetic resistance of the demagnetizing magnetic circuit at the outer end of the permanent magnet, improving its demagnetization resistance. It also reduces the presence of sharp edges and corners, avoids magnetic field distortion caused by sharp corners, improves the magnetic concentration effect at inflection points, and solves the problem of poor demagnetization resistance in permanent magnet motors. The inherent material properties of permanent magnets mean that they will demagnetize under high temperature and high current. Permanent magnets have corresponding weak points for demagnetization, concentrated at the edges and corners. By widening and thickening these areas, the demagnetization resistance can be improved.

[0029] As an optional embodiment of the present invention, such as Figure 1 As shown, two adjacent permanent magnets are arranged in a V-shape to form one of the rotor magnetic poles; specifically, the two adjacent permanent magnets are a first permanent magnet 1 and a second permanent magnet 2, which are arranged at a V-angle; each pair of first permanent magnets 1 and second permanent magnets 2 forms one rotor magnetic pole, as shown. Figure 1 As shown in the figure, this is a rotor structure with six rotor poles: the first, second, third, fourth, fifth, and sixth rotor poles. The included angle β between the rotor poles ranges from 90° to 130°. A smaller included angle β increases the depth of the permanent magnet's penetration, resulting in a smaller area between the permanent magnet and the high-density magnetic field lines of the rotor's magnetic isolation bridge 9. Under the influence of the demagnetizing magnetic field, the area prone to demagnetization of the permanent magnet is reduced, thus improving the overall demagnetization resistance of the motor.

[0030] like Figure 4 As shown, the second end face 11 of the permanent magnet is a plane, and the magnetization direction of the permanent magnet is perpendicular to the second end face 11. The first rotor magnetic pole and the second rotor magnetic pole are magnetized in the same direction and are built into the rotor core 3, exhibiting the same polarity, becoming the S pole or N pole in the rotor magnetic pole. In the rotor core 3, the S pole and N pole are alternately distributed.

[0031] like Figure 4 or Figure 5As shown, in an optional embodiment of the present invention, the thickness difference Δt between the end thickness T and the center thickness t of the permanent magnet satisfies the following relationship: 0 < Δt < t / 6.

[0032] Specifically, the permanent magnets on the first end face 10 facing the outside of the rotor core 3 gradually thicken towards both ends, with the first end face 10 having an arc-shaped structure. The maximum thickness at both ends of the permanent magnet is T, and the minimum thickness at the center is t. Thickening the permanent magnets helps to improve their ability to withstand demagnetizing magnetic fields, enhances their overall resistance to demagnetization, makes the motor less prone to demagnetization, and improves the reliability of the motor.

[0033] Alternatively, the permanent magnets on the first end face 10 facing the outside of the rotor core 3 are symmetrically thickened towards both ends, with the first end face 10 having a V-shaped inclined structure. The maximum thickness at both ends of the permanent magnet is T, and the minimum thickness at the center is t. It should be noted that the arc-shaped structure of the first end face 10 of the permanent magnet can adopt the following two embodiments: like Figure 4 As shown, in an optional embodiment of the present invention, the first end face 10 of the permanent magnet is a full circular arc structure, and the radius R1 of the arc corresponding to the first end face 10 of the permanent magnet satisfies the following relationship: R1=(k 2 +△t 2 ) / 2△t, where k is half the width of the permanent magnet.

[0034] like Figure 5 As shown, in another optional embodiment of the present invention, the first end face 10 of the permanent magnet includes a straight section and arc segments located on both sides of the straight section; the radius R0 of the arc segment satisfies the following relationship: R0=(K 2 +K0 2 -2KK0+4△t 2 ) / 8△t; where K0 is the width of the straight section and K is the width of the permanent magnet.

[0035] To improve the utilization rate of the permanent magnet's magnetic field and shorten the distance traveled through the air along the magnetic field lines, the distance between the edge of the permanent magnet and its sidewall is no greater than 0.05 mm. Specifically, the first end face 5 and the second end face 6 of the permanent magnet slot correspond one-to-one with the first end face 10 and the second end face 11 of the permanent magnet. By shortening the distance traveled through the air along the magnetic field lines, the magnetic resistance is reduced. A smaller distance on one side increases the utilization rate of the permanent magnet's magnetic field, which is beneficial for reducing motor copper losses and improving motor efficiency.

[0036] like Figure 1 , Figure 3 , Figure 6 and Figure 7As shown, as a further improvement of the present invention, the magnetically shielding air slot includes a first air slot 7 and a second air slot 8; the first air slot 7 is formed on the side of the permanent magnet slot near the outer circle of the rotor core 3 and extends towards another permanent magnet slot in the same rotor pole; the second air slot 8 is formed on the permanent magnet slot near the center of the rotor core 3 (near the d-axis end) and communicates with another second air slot 8 in the same rotor pole. The specific dimensions and areas of the first air slot 7 and the second air slot 8 are not required.

[0037] With the above structural setup, there are two first air slots 7 and one second air slot 8 in the rotor with the same polarity. The air slots are connected to the permanent magnet slots. Since the magnetic permeability of air is much smaller than that of the silicon steel sheet material of the rotor core 3, the magnetic lines of force are relatively dense in the area of ​​the permanent magnet near the outer side of the rotor and in the d-axis direction. When there is a reverse instantaneous current, these two areas of the permanent magnet are greatly affected and have a greater risk of demagnetization. Therefore, air slots are set around the parts of the permanent magnet that are prone to demagnetization, namely the two areas mentioned above. By opening air slots around the parts of the permanent magnet that are prone to demagnetization, the magnetic resistance of the area is increased, the demagnetizing magnetic field in the area is weakened, the magnetic flux density of the permanent magnet in the area is reduced, the occurrence of irreversible demagnetization of the permanent magnet is reduced, and the motor's anti-demagnetization ability is improved.

[0038] In this embodiment, the first air slot 7 and the outer circle of the rotor core 3 are concentric circles; as shown Figure 7 As shown, a magnetic bridge 9 is formed between the outer edge of the first air slot 7 and the outer edge of the rotor core 3, and the thickness of the magnetic bridge 9 is 0.3mm-0.6mm.

[0039] To reduce magnetic leakage at the ends of permanent magnets, improve the utilization rate of permanent magnets, and increase motor efficiency, the magnetic shielding structure is very thin, with a thickness of 0.3mm to 0.6mm. This structural design solves the problems of low motor efficiency, easy demagnetization of permanent magnets near the outer circle of the rotor, and easy demagnetization of permanent magnets near the d-axis.

[0040] As a further improvement to the present invention, such as Figure 2 and Figure 3 As shown, the magnetic baffle 4 has a circular ring structure with a diameter smaller than the inner diameter of the first air groove 7 and an inner ring diameter larger than the outer diameter of the second air groove 8.

[0041] The function of the rotor magnetic baffle 4 is to block the permanent magnet and prevent it from flying out during rotor rotation. The rotor magnetic baffle 4 is required not to cover the first and second air slots 8. When the compressor is working, the airflow flows through the air slots, which helps to reduce the temperature of the permanent magnet, making it less likely for the permanent magnet to reach the demagnetization condition, reducing the thermal demagnetization effect caused by the excessive heating temperature of the permanent magnet, making the motor less prone to demagnetization, and improving the reliability of the motor.

[0042] Example 2: In this embodiment, the present invention provides a permanent magnet motor, including a rotor structure.

[0043] Among them, such as Figure 1 As shown, the rotor structure includes a magnetic baffle plate 4, a rotor core 3, and permanent magnets; the rotor core 3 is uniformly provided with a number of permanent magnet slots along its circumference; the permanent magnet slots have two opposite large end faces, namely the first end face 5 and the second end face 6 of the permanent magnet slot; the permanent magnets are embedded in the permanent magnet slots; the magnetic baffle plate 4 is arranged on the top of the rotor core 3; and a magnetic shielding air slot is provided at the end of the permanent magnet slot.

[0044] It should be noted that the permanent magnet also has two relatively large end faces, namely: the first end face 10 of the permanent magnet and the second end face 11 of the permanent magnet; the first end face 10 of the permanent magnet and the first end face 5 of the permanent magnet groove are correspondingly arranged, and the second end face 11 of the permanent magnet and the second end face 6 of the permanent magnet groove are correspondingly arranged, and their shapes are compatible; in this embodiment, as Figure 4 As shown in Figure 5, the second end face 11 of the permanent magnet is a plane, and the first end face 10 of the permanent magnet is a V-shaped inclined surface or arc surface structure with a concave middle and convex ends. This structure makes the two ends of the permanent magnet thick and the middle thin.

[0045] External factors causing motor demagnetization include: 1. Permanent magnet synchronous motors are used in air conditioning compressors, where the internal airflow is high-pressure, high-temperature gas; 2. The reverse instantaneous current experienced by the motor during startup.

[0046] like Figure 6 As shown, in order to improve motor efficiency, the present invention provides a rotor structure that improves the demagnetization area and effectively reduces the risk of demagnetization by optimizing the end face shape of the permanent magnet, thickening the permanent magnets at both ends and designing the magnetic isolation air groove (thinning magnetic isolation bridge 9 architecture). By optimizing the magnetic isolation bridge 9 architecture, the leakage magnetic flux at the end of the permanent magnet is reduced, thereby improving the utilization rate of the permanent magnet, enhancing the overall performance and stability of the motor, and ensuring the long-term efficient operation of the system.

[0047] like Figure 4 or Figure 5 As shown, as a further improvement of the present invention, the four corners (the four sides between the four adjacent planes, a total of four sides) of the permanent magnet along the length direction (axial direction of the rotor core 3) are provided with rounded chamfer structures R, and the radius a of the rounded chamfer structure R should satisfy: 0.3 < 2a < T, where T is the thickness at the widest point of the permanent magnet. Through this structural improvement, the magnetic focusing effect at the inflection point is improved, and the magnetic resistance of the demagnetizing magnetic circuit at the outer end of the permanent magnet in this region is increased, thereby reducing the demagnetizing effect.

[0048] The magnetic field is concentrated at the edges and corners of permanent magnets, making them more prone to demagnetization under reverse forces. This leads to magnetic distortion at the sharp corners of the permanent magnets. To reduce the presence of sharp edges and corners, and to reduce local magnetic field concentration, rounded corners are designed. This increases the magnetic resistance of the demagnetizing magnetic circuit at the outer end of the permanent magnet, improving its demagnetization resistance. It also reduces the presence of sharp edges and corners, avoids magnetic field distortion caused by sharp corners, improves the magnetic concentration effect at inflection points, and solves the problem of poor demagnetization resistance in permanent magnet motors. The inherent material properties of permanent magnets mean that they will demagnetize under high temperature and high current. Permanent magnets have corresponding weak points for demagnetization, concentrated at the edges and corners. By widening and thickening these areas, the demagnetization resistance can be improved.

[0049] As an optional embodiment of the present invention, such as Figure 1 As shown, two adjacent permanent magnets are arranged in a V-shape to form one of the rotor magnetic poles; specifically, the two adjacent permanent magnets are a first permanent magnet 1 and a second permanent magnet 2, which are arranged at a V-angle; each pair of first permanent magnets 1 and second permanent magnets 2 forms one rotor magnetic pole, as shown. Figure 1 As shown in the figure, this is a rotor structure with six rotor poles: the first, second, third, fourth, fifth, and sixth rotor poles. The included angle β between the rotor poles ranges from 90° to 130°. A smaller included angle β increases the depth of the permanent magnet's penetration, resulting in a smaller area between the permanent magnet and the high-density magnetic field lines of the rotor's magnetic isolation bridge 9. Under the influence of the demagnetizing magnetic field, the area prone to demagnetization of the permanent magnet is reduced, thus improving the overall demagnetization resistance of the motor.

[0050] like Figure 4 As shown, the second end face 11 of the permanent magnet is a plane, and the magnetization direction of the permanent magnet is perpendicular to the second end face 11. The first rotor magnetic pole and the second rotor magnetic pole are magnetized in the same direction and are built into the rotor core 3, exhibiting the same polarity, becoming the S pole or N pole in the rotor magnetic pole. In the rotor core 3, the S pole and N pole are alternately distributed.

[0051] like Figure 4 or Figure 5 As shown, in an optional embodiment of the present invention, the thickness difference Δt between the end thickness T and the center thickness t of the permanent magnet satisfies the following relationship: 0 < Δt < t / 6.

[0052] Specifically, the permanent magnet faces the outside of the rotor core 3. The first end face 10 of the permanent magnet gradually thickens towards both ends in a symmetrical manner. The first end face 10 of the permanent magnet has an arc-shaped structure. The maximum thickness at both ends of the permanent magnet is T, and the minimum thickness at the center is t.

[0053] Alternatively, the permanent magnets on the first end face 10 facing the outside of the rotor core 3 are symmetrically thickened towards both ends, with the first end face 10 having a V-shaped inclined structure. The maximum thickness at both ends of the permanent magnet is T, and the minimum thickness at the center is t. It should be noted that the arc-shaped structure of the first end face 10 of the permanent magnet can adopt the following two embodiments: like Figure 4 As shown, in an optional embodiment of the present invention, the first end face 10 of the permanent magnet is a full circular arc structure, and the radius R1 of the arc corresponding to the first end face 10 of the permanent magnet satisfies the following relationship: R1=(k 2 +△t 2 ) / 2△t, where k is half the width of the permanent magnet.

[0054] like Figure 5 As shown, in another optional embodiment of the present invention, the first end face 10 of the permanent magnet includes a straight section and arc segments located on both sides of the straight section; the radius R0 of the arc segment satisfies the following relationship: R0=(K 2 +K0 2 -2KK0+4△t 2 ) / 8△t; where K0 is the width of the straight section and K is the width of the permanent magnet.

[0055] As a further improvement of the present invention, the distance between the edge of the permanent magnet and the sidewall of the permanent magnet is no greater than 0.05 mm. Specifically, the first end face 5 and the second end face 6 of the permanent magnet slot correspond one-to-one with the first end face 10 and the second end face 11 of the permanent magnet. To improve the utilization rate of the permanent magnet's magnetic field and shorten the distance traveled through the air along the direction of the magnetic field lines, the single-sided distance between the permanent magnet and the permanent magnet slot is controlled to be less than 0.05 mm.

[0056] like Figure 1 , Figure 3 , Figure 6 and Figure 7 As shown, as a further improvement of the present invention, the magnetically shielding air slot includes a first air slot 7 and a second air slot 8; the first air slot 7 is formed on the side of the permanent magnet slot near the outer circle of the rotor core 3 and extends towards another permanent magnet slot in the same rotor pole; the second air slot 8 is formed on the permanent magnet slot near the center of the rotor core 3 (near the d-axis end) and communicates with another second air slot 8 in the same rotor pole. The specific dimensions and areas of the first air slot 7 and the second air slot 8 are not required.

[0057] With the above structural setup, there are two first air slots 7 and one second air slot 8 in the rotor with the same polarity. The air slots are connected to the permanent magnet slots. The magnetic permeability of air is much smaller than that of the silicon steel sheet material of the rotor core 3. The magnetic field lines of the permanent magnet are relatively dense in the area near the outer side of the rotor and in the d-axis direction. When there is a reverse instantaneous current, these two areas of the permanent magnet are greatly affected and have a greater risk of demagnetization. Therefore, air slots are set in these two areas. By opening air slots around the easily demagnetized parts of the permanent magnet, the magnetic resistance of the area is increased, the demagnetizing magnetic field in the area is weakened, the magnetic flux density of the permanent magnet in the area is reduced, and the occurrence of irreversible demagnetization of the permanent magnet is reduced.

[0058] In this embodiment, the first air slot 7 and the outer circle of the rotor core 3 are concentric circles; as shown Figure 7 As shown, a magnetic bridge 9 is formed between the outer edge of the first air slot 7 and the outer edge of the rotor core 3, and the thickness of the magnetic bridge 9 is 0.3mm-0.6mm.

[0059] To reduce magnetic leakage at the end of the permanent magnet, improve the utilization rate of the permanent magnet, and increase the efficiency of the motor, the magnetic shielding structure is very thin, with a thickness of 0.3mm to 0.6mm.

[0060] As a further improvement to the present invention, such as Figure 2 and Figure 3 As shown, the magnetic baffle 4 has a circular ring structure with a diameter smaller than the inner diameter of the first air groove 7 and an inner ring diameter larger than the outer diameter of the second air groove 8.

[0061] The function of the rotor magnetic baffle 4 is to block the permanent magnet and prevent it from flying out during rotor rotation. The rotor magnetic baffle 4 is required not to cover the first and second air slots 8. Airflow flows through the air slots to reduce the thermal demagnetization effect caused by excessive heating of the permanent magnet.

[0062] Example 3: The present invention provides a compressor, including the aforementioned permanent magnet motor.

[0063] Furthermore, permanent magnet motors include a rotor structure.

[0064] like Figure 1 As shown, the rotor structure includes a magnetic baffle plate 4, a rotor core 3, and permanent magnets; the rotor core 3 is uniformly provided with a number of permanent magnet slots along its circumference; the permanent magnet slots have two opposite large end faces, namely the first end face 5 and the second end face 6 of the permanent magnet slot; the permanent magnets are embedded in the permanent magnet slots; the magnetic baffle plate 4 is arranged on the top of the rotor core 3; and a magnetic shielding air slot is provided at the end of the permanent magnet slot.

[0065] It should be noted that the permanent magnet also has two relatively large end faces, namely: the first end face 10 of the permanent magnet and the second end face 11 of the permanent magnet; the first end face 10 of the permanent magnet and the first end face 5 of the permanent magnet groove are correspondingly arranged, and the second end face 11 of the permanent magnet and the second end face 6 of the permanent magnet groove are correspondingly arranged, and their shapes are compatible; in this embodiment, as Figure 4 As shown in Figure 5, the second end face 11 of the permanent magnet is a plane, and the first end face 10 of the permanent magnet is a V-shaped inclined surface or arc surface structure with a concave middle and convex ends. This structure makes the two ends of the permanent magnet thick and the middle thin.

[0066] External factors causing motor demagnetization include: 1. Permanent magnet synchronous motors are used in air conditioning compressors, where the internal airflow is high-pressure, high-temperature gas; 2. The reverse instantaneous current experienced by the motor during startup.

[0067] like Figure 6 As shown, in order to improve motor efficiency, the present invention provides a rotor structure that improves the demagnetization area and effectively reduces the risk of demagnetization by optimizing the end face shape of the permanent magnet, thickening the permanent magnets at both ends and designing the magnetic isolation air groove (thinning magnetic isolation bridge 9 architecture). By optimizing the magnetic isolation bridge 9 architecture, the leakage magnetic flux at the end of the permanent magnet is reduced, thereby improving the utilization rate of the permanent magnet, enhancing the overall performance and stability of the motor, and ensuring the long-term efficient operation of the system.

[0068] like Figure 4 or Figure 5 As shown, as a further improvement of the present invention, the four corners (the four sides between the four adjacent planes, a total of four sides) of the permanent magnet along the length direction (axial direction of the rotor core 3) are provided with rounded chamfer structures R, and the radius a of the rounded chamfer structure R should satisfy: 0.3 < 2a < T, where T is the thickness at the widest point of the permanent magnet. Through this structural improvement, the magnetic focusing effect at the inflection point is improved, and the magnetic resistance of the demagnetizing magnetic circuit at the outer end of the permanent magnet in this region is increased, thereby reducing the demagnetizing effect.

[0069] The magnetic field is concentrated at the edges and corners of permanent magnets, making them more prone to demagnetization under reverse forces. This leads to magnetic distortion at the sharp corners of the permanent magnets. To reduce the presence of sharp edges and corners, and to reduce local magnetic field concentration, rounded corners are designed. This increases the magnetic resistance of the demagnetizing magnetic circuit at the outer end of the permanent magnet, improving its demagnetization resistance. It also reduces the presence of sharp edges and corners, avoids magnetic field distortion caused by sharp corners, improves the magnetic concentration effect at inflection points, and solves the problem of poor demagnetization resistance in permanent magnet motors. The inherent material properties of permanent magnets mean that they will demagnetize under high temperature and high current. Permanent magnets have corresponding weak points for demagnetization, concentrated at the edges and corners. By widening and thickening these areas, the demagnetization resistance can be improved.

[0070] As an optional embodiment of the present invention, such as Figure 1As shown, two adjacent permanent magnets are arranged in a V-shape to form one of the rotor magnetic poles; specifically, the two adjacent permanent magnets are a first permanent magnet 1 and a second permanent magnet 2, which are arranged at a V-angle; each pair of first permanent magnets 1 and second permanent magnets 2 forms one rotor magnetic pole, as shown. Figure 1 As shown in the figure, this is a rotor structure with six rotor poles: the first, second, third, fourth, fifth, and sixth rotor poles. The included angle β between the rotor poles ranges from 90° to 130°. A smaller included angle β increases the depth of the permanent magnet's penetration, resulting in a smaller area between the permanent magnet and the high-density magnetic field lines of the rotor's magnetic isolation bridge 9. Under the influence of the demagnetizing magnetic field, the area prone to demagnetization of the permanent magnet is reduced, thus improving the overall demagnetization resistance of the motor.

[0071] like Figure 4 As shown, the second end face 11 of the permanent magnet is a plane, and the magnetization direction of the permanent magnet is perpendicular to the second end face 11. The first rotor magnetic pole and the second rotor magnetic pole are magnetized in the same direction and are built into the rotor core 3, exhibiting the same polarity, becoming the S pole or N pole in the rotor magnetic pole. In the rotor core 3, the S pole and N pole are alternately distributed.

[0072] like Figure 4 or Figure 5 As shown, in an optional embodiment of the present invention, the thickness difference Δt between the end thickness T and the center thickness t of the permanent magnet satisfies the following relationship: 0 < Δt < t / 6.

[0073] Specifically, the permanent magnet faces the outside of the rotor core 3. The first end face 10 of the permanent magnet gradually thickens towards both ends in a symmetrical manner. The first end face 10 of the permanent magnet has an arc-shaped structure. The maximum thickness at both ends of the permanent magnet is T, and the minimum thickness at the center is t.

[0074] Alternatively, the permanent magnets on the first end face 10 facing the outside of the rotor core 3 are symmetrically thickened towards both ends, with the first end face 10 having a V-shaped inclined structure. The maximum thickness at both ends of the permanent magnet is T, and the minimum thickness at the center is t. It should be noted that the arc-shaped structure of the first end face 10 of the permanent magnet can adopt the following two embodiments: like Figure 4 As shown, in an optional embodiment of the present invention, the first end face 10 of the permanent magnet is a full circular arc structure, and the radius R1 of the arc corresponding to the first end face 10 of the permanent magnet satisfies the following relationship: R1=(k 2 +△t 2 ) / 2△t, where k is half the width of the permanent magnet.

[0075] like Figure 5As shown, in another optional embodiment of the present invention, the first end face 10 of the permanent magnet includes a straight section and arc segments located on both sides of the straight section; the radius R0 of the arc segment satisfies the following relationship: R0=(K 2 +K0 2 -2KK0+4△t 2 ) / 8△t; where K0 is the width of the straight section and K is the width of the permanent magnet.

[0076] As a further improvement of the present invention, the distance between the edge of the permanent magnet and the sidewall of the permanent magnet is no greater than 0.05 mm. Specifically, the first end face 5 and the second end face 6 of the permanent magnet slot correspond one-to-one with the first end face 10 and the second end face 11 of the permanent magnet. To improve the utilization rate of the permanent magnet's magnetic field and shorten the distance traveled through the air along the direction of the magnetic field lines, the single-sided distance between the permanent magnet and the permanent magnet slot is controlled to be less than 0.05 mm.

[0077] like Figure 1 , Figure 3 , Figure 6 and Figure 7 As shown, as a further improvement of the present invention, the magnetically shielding air slot includes a first air slot 7 and a second air slot 8; the first air slot 7 is formed on the side of the permanent magnet slot near the outer circle of the rotor core 3 and extends towards another permanent magnet slot in the same rotor pole; the second air slot 8 is formed on the permanent magnet slot near the center of the rotor core 3 (near the d-axis end) and communicates with another second air slot 8 in the same rotor pole. The specific dimensions and areas of the first air slot 7 and the second air slot 8 are not required.

[0078] With the above structural setup, there are two first air slots 7 and one second air slot 8 in the rotor with the same polarity. The air slots are connected to the permanent magnet slots. The magnetic permeability of air is much smaller than that of the silicon steel sheet material of the rotor core 3. The magnetic field lines of the permanent magnet are relatively dense in the area near the outer side of the rotor and in the d-axis direction. When there is a reverse instantaneous current, these two areas of the permanent magnet are greatly affected and have a greater risk of demagnetization. Therefore, air slots are set in these two areas. By opening air slots around the easily demagnetized parts of the permanent magnet, the magnetic resistance of the area is increased, the demagnetizing magnetic field in the area is weakened, the magnetic flux density of the permanent magnet in the area is reduced, and the occurrence of irreversible demagnetization of the permanent magnet is reduced.

[0079] In this embodiment, the first air slot 7 and the outer circle of the rotor core 3 are concentric circles; as shown Figure 7 As shown, a magnetic bridge 9 is formed between the outer edge of the first air slot 7 and the outer edge of the rotor core 3, and the thickness of the magnetic bridge 9 is 0.3mm-0.6mm.

[0080] To reduce magnetic leakage at the end of the permanent magnet, improve the utilization rate of the permanent magnet, and increase the efficiency of the motor, the magnetic shielding structure is very thin, with a thickness of 0.3mm to 0.6mm.

[0081] As a further improvement to the present invention, such as Figure 2 and Figure 3 As shown, the magnetic baffle 4 has a circular ring structure with a diameter smaller than the inner diameter of the first air groove 7 and an inner ring diameter larger than the outer diameter of the second air groove 8.

[0082] The function of the rotor magnetic baffle 4 is to block the permanent magnet and prevent it from flying out during rotor rotation. The rotor magnetic baffle 4 is required not to cover the first and second air slots 8. Airflow flows through the air slots to reduce the thermal demagnetization effect caused by excessive heating of the permanent magnet.

[0083] The compressor of this invention includes a permanent magnet motor, which comprises a rotor structure with permanent magnets. The purpose is to improve the motor's demagnetization resistance and increase its efficiency. Based on the demagnetization characteristics of permanent magnet motors, the weak points in the permanent magnet's demagnetization resistance are concentrated at the corners. By chamfering the corners of the permanent magnet to increase the magnetic resistance at the outer end of the permanent magnet to withstand the demagnetization magnetic circuit, the demagnetization resistance is improved. The magnetic flux density cloud diagram of the rotor permanent magnet after demagnetization is shown below. Figure 6 As shown, the closer the color of the permanent magnet is to the bottom layer color, the lower the magnetic flux density in that area, and the more obvious the demagnetization phenomenon.

[0084] As can be seen from the cloud map, the first weak point of the permanent magnet is located in the area near the outer circle of the rotor. Since this area has a magnetic shielding structure, the thickness of the magnetic shielding structure is very thin in order to reduce magnetic leakage at the end of the permanent magnet and improve the utilization rate of the permanent magnet. The magnetic lines of force in this area are particularly dense. When the permanent magnet is subjected to a counteracting magnetic field, the permanent magnet in this area is extremely easy to demagnetize. This invention specifically optimizes the permanent magnet structure in this area by increasing the thickness at both ends of the permanent magnet to improve the resistance to demagnetization. The second weakness lies in the region of the permanent magnet near the d-axis, which is the center line of the magnetic pole (a magnetic pole composed of two permanent magnets is a V-shaped structure; the d-axis is located at the symmetrical center line of the two permanent magnets). This region is where the magnetic lines of force are relatively dense in a closed magnetic circuit. This invention specifically optimizes the permanent magnet structure in this region by setting a first air slot 7 and a second air slot 8, and by locally optimizing the design at both ends of the permanent magnet and optimizing the structure at both ends of the rotor permanent magnet slot. This solves the problem of easy demagnetization of the permanent magnet near the outer circle of the rotor and near the d-axis, improves the demagnetization resistance of the permanent magnet motor, optimizes the distribution of magnetic lines of force, reduces the motor operating current, reduces copper loss, and improves motor efficiency.

[0085] First, it should be noted that "inward" refers to the direction towards the center of the storage space, while "outward" refers to the direction away from the center of the storage space.

[0086] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the purpose of facilitating and simplifying the description of the present invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0087] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0088] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0089] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0090] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0091] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A rotor structure, characterized in that, It includes a magnetic baffle plate, a rotor core, and permanent magnets; the rotor core is uniformly provided with a plurality of permanent magnet slots along its circumference; the permanent magnets are embedded in the permanent magnet slots; the magnetic baffle plate is arranged on the top of the rotor core; the end of each permanent magnet slot is provided with a magnetically shielding air slot; the permanent magnet has a first end face and a second end face; the second end face of the permanent magnet is a plane, and the first end face of the permanent magnet is a V-shaped inclined surface or arc surface structure with a concave middle and convex ends.

2. The rotor structure according to claim 1, characterized in that, The permanent magnet has rounded corner structures R at all four corners along its length, and the radius a of the rounded corner structure R should satisfy: 0.3 < 2a < T, where T is the thickness at the widest point of the permanent magnet.

3. The rotor structure according to claim 1, characterized in that, The two adjacent permanent magnets are arranged in a V-shape to form rotor magnetic poles; the included angle β of the rotor magnetic poles is in the range of 90°≤β≤130°.

4. The rotor structure according to claim 1, characterized in that, The thickness difference Δt between the end thickness T and the center thickness t of the permanent magnet satisfies the following relationship: 0 < Δt < t / 6.

5. The rotor structure according to claim 4, characterized in that, The first end face of the permanent magnet is a full circular arc structure, and the radius R1 of the arc corresponding to the first end face of the permanent magnet satisfies the following relationship: R1=(k 2 +△t 2 ) / 2△t, where k is half the width of the permanent magnet; or; the first end face of the permanent magnet includes a straight section and arc segments located on both sides of the straight section; the radius R0 of the arc segment satisfies the following relationship: R0=(K 2 +K0 2 -2KK0+4△t 2 ) / 8△t; where K0 is the width of the straight section and K is the width of the permanent magnet.

6. The rotor structure according to claim 1, characterized in that, The distance between the edge of the permanent magnet and the sidewall of the permanent magnet is no greater than 0.05 mm.

7. The rotor structure according to claim 3, characterized in that, The magnetically shielding air slot includes a first air slot and a second air slot; the first air slot is formed on the permanent magnet slot near the outer circle of the rotor core and extends toward the other permanent magnet slot in the same rotor pole; the second air slot is formed on the permanent magnet slot near the center of the rotor core and communicates with the other second air slot in the same rotor pole.

8. The rotor structure according to claim 7, characterized in that, The first air slot and the outer circle of the rotor core are concentric circles; a magnetic bridge is formed between the outer edge of the first air slot and the outer edge of the rotor core, and the thickness of the magnetic bridge is 0.3mm-0.6mm.

9. The rotor structure according to claim 7, characterized in that, The magnetic baffle plate has a circular structure with a diameter smaller than the inner diameter of the first air groove and an inner ring diameter larger than the outer diameter of the second air groove.

10. An electric motor, characterized in that, Includes the rotor structure as described in any one of claims 1-9.

11. A compressor, characterized in that, Including the motor as described in claim 10.

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