Motor rotor, motor, compressor and household appliance

Abstract

The application relates to a motor rotor, a motor, a compressor and a household appliance, and relates to the technical field of permanent magnet synchronous motors. The motor rotor comprises a rotor core, a plurality of permanent magnet slot groups are arranged on the rotor core, the permanent magnet slot group comprises a first permanent magnet slot, the first permanent magnet slot comprises first and second slot sections which are spaced apart, and a third slot section which is connected between the first and second slot sections; a first permanent magnet is arranged in the first slot section, the first permanent magnet has a first pole surface which faces the second slot section; a second permanent magnet is arranged in the second slot section, the second permanent magnet has a second pole surface which faces the first slot section; and a third permanent magnet is arranged in the third slot section, a first end of the third permanent magnet abuts against the first pole surface, and a second end of the third permanent magnet abuts against the second pole surface. The anti-demagnetization capability of the motor rotor is improved, and the magnetic leakage occurring between the first and second permanent magnets is avoided, so that the utilization rate of the permanent magnets is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors, and in particular to a motor rotor, a motor and a compressor. Background Art

[0002] Interior permanent magnet synchronous motors (IPMS) have permanent magnets inserted into their rotors, offering advantages such as high reluctance torque and strong field-weakening speed expansion. Conventional IPMMS use a single-piece permanent magnet structure, which is inserted tangentially into the rotor core's magnetic slots to increase motor torque.

[0003] In the related art, the magnets in the rotor core are arranged into a V-shaped structure symmetrical along the d-axis, which can utilize the radial space of the rotor core, increase the amount of magnets used, improve the magnetic conductivity density of the motor rotor, and improve the performance of the rotor.

[0004] However, when the rotor load of a permanent magnet synchronous motor is too large, armature reaction will occur, causing the permanent magnet to demagnetize. The V-shaped structure is formed by two separate sections of magnetic steel. After unilateral demagnetization, the rotor's magnetic field will suddenly change, which will easily lead to increased iron loss and copper loss of the motor and reduced efficiency. Summary of the Invention

[0005] The present invention provides a motor rotor, a motor, a compressor and a household appliance, which are used to enhance the anti-demagnetization capability of the motor rotor and improve the performance of the motor.

[0006] In a first aspect, the present invention provides a motor rotor, comprising: a rotor core, a plurality of permanent magnet slot groups provided on the rotor core, the permanent magnet slot groups including a first permanent magnet slot, the first permanent magnet slot including a first slot segment and a second slot segment spaced apart from each other, and a third slot segment connecting the first slot segment and the second slot segment;

[0007] a first permanent magnet installed in the first slot segment, the first permanent magnet having a first pole face facing the second slot segment;

[0008] a second permanent magnet mounted in the second slot segment, the second permanent magnet having a second pole face facing the first slot segment; and

[0009] A third permanent magnet is installed in the third slot segment, wherein a first end of the third permanent magnet abuts against the first pole surface, and a second end of the third permanent magnet abuts against the second pole surface.

[0010] In one embodiment, the first permanent magnet and the second permanent magnet are arranged at an angle, and the gap between the first permanent magnet and the second permanent magnet gradually increases in the radial direction, and the distance between the inner end of the first permanent magnet and the inner end of the second permanent magnet is a first length;

[0011] The radial outer side surface of the third permanent magnet is in contact with the inner wall of the third slot segment. The third permanent magnet is located between the first permanent magnet and the second permanent magnet. The length of the third permanent magnet along the tangential direction of the rotor core is greater than the first length.

[0012] In one embodiment, a first beveled wedge surface is provided at the first end of the third permanent magnet, and a second beveled wedge surface is provided at the second end of the third permanent magnet. The first beveled wedge surface is in contact with and abuts the first pole surface, and the second beveled wedge surface is in contact with and abuts the second pole surface.

[0013] In one embodiment, a fourth permanent magnet is further installed in the third slot segment and is spaced apart from the third permanent magnet. The fourth permanent magnet is located on a side of the third permanent magnet close to the center of the rotor core, and the inner side surface of the fourth permanent magnet is in contact with the inner wall of the third slot segment.

[0014] One end of the fourth permanent magnet is provided with a third inclined wedge surface, which abuts the inner end surface of the first permanent magnet. The other end of the fourth permanent magnet is provided with a fourth inclined wedge surface, which abuts the inner end surface of the second permanent magnet.

[0015] In one embodiment, the third permanent magnet and the fourth permanent magnet both extend along a straight line, and the third permanent magnet is parallel to the fourth permanent magnet.

[0016] In one embodiment, the angle between the first slot segment and the third slot segment is φ1, wherein 135°≤φ1≤155°.

[0017] In one embodiment, the first permanent magnet and the second permanent magnet are symmetrical along a first straight line, the first straight line passes through the center of the rotor core's rotation axis along the radial direction of the rotor core, and the third permanent magnet is perpendicular to the first straight line and symmetrical along the first straight line.

[0018] In one embodiment, the first permanent magnet and the second permanent magnet are symmetrical along the first straight line, and the permanent magnet slot group also includes a second permanent magnet slot and a third permanent magnet slot symmetrical along the first straight line. The second permanent magnet slot and the third permanent magnet slot are both located radially outside the third slot segment, and the rotor core is also provided with a magnetic flux sorting slot between the second permanent magnet slot and the third permanent magnet slot.

[0019] In one embodiment, the second permanent magnet slot includes a fourth slot segment and a fifth slot segment, wherein permanent magnets are respectively installed in the fourth slot segment and the fifth slot segment, and the fifth slot segment is parallel to the second slot segment;

[0020] The fourth slot segment is arranged at an angle to the fifth slot segment, one end of the fourth slot segment is connected to the fifth slot segment, and the other end of the fourth slot segment extends toward the outer edge of the rotor core.

[0021] In one embodiment, a plurality of trimming grooves are provided on the outer edge of the rotor core. The number of the trimming grooves is equal to the number of the permanent magnet slot groups. Each trimming groove is provided between two adjacent permanent magnet slot groups.

[0022] In a second aspect, the present invention further provides a motor comprising the above-mentioned motor rotor.

[0023] In a third aspect, the present invention further provides a compressor comprising the above-mentioned motor.

[0024] In a fourth aspect, the present invention further provides a household appliance comprising the above-mentioned motor.

[0025] Compared with the existing technology, the present invention has the advantage of aligning the first end of the third permanent magnet with the first pole face of the first permanent magnet, utilizing the magnetic material at the first end of the third permanent magnet to improve the magnetic field environment of the first permanent magnet under strong magnetic conditions. This is equivalent to using the third permanent magnet to increase the thickness of the first permanent magnet, thereby improving the first permanent magnet's resistance to demagnetization. Similarly, the second end of the third permanent magnet aligns with the second pole face, thereby improving the second permanent magnet's resistance to demagnetization. This improves the motor rotor's resistance to demagnetization.

[0026] In addition, the first permanent magnet and the second permanent magnet, which are spaced apart from each other, are connected by a third permanent magnet arranged in the third slot segment. The magnetic permeability density of the area between the first permanent magnet and the second permanent magnet is increased by the third permanent magnet, thereby avoiding magnetic leakage between the first permanent magnet and the second permanent magnet and improving the utilization rate of the permanent magnets. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Hereinafter, the present invention will be described in more detail based on embodiments with reference to the accompanying drawings.

[0028] Figure 1 is an end view of a rotor core according to an embodiment of the present invention;

[0029] Figure 2 is a schematic end view of a motor rotor in an embodiment of the present invention;

[0030] Figure 3 yes Figure 2 Schematic diagram of the local structure in;

[0031] Figure 4 is an end view of a rotor core according to an embodiment of the present invention;

[0032] Figure 5 It is a schematic diagram of the partial structure of the rotor core;

[0033] Figure 6 It is a schematic diagram of the partial structure of the rotor core;

[0034] Figure 7is a partial structure diagram of a rotor core;

[0035] Figure 8 is a back EMF waveform diagram of a motor in an embodiment of the present application;

[0036] Figure 9 is a back EMF waveform diagram of a motor in the prior art;

[0037] Figure 10 is a curve diagram of motor efficiency of a motor in an embodiment of the present application and a motor in the prior art;

[0038] Figure 11 is a curve diagram of demagnetization rate of a motor in an embodiment of the present application and a motor in the prior art;

[0039] Figure 12 is a motor structure diagram in an embodiment of the present application with each permanent magnet hidden.

[0040] Reference Signs:

[0041] 100, rotor core;

[0042] 110, first permanent magnet slot; 111, first slot section; 112, second slot section; 113, third slot section;

[0043] 120, second permanent magnet slot; 121, fourth slot section; 122, fifth slot section;

[0044] 130, third permanent magnet slot;

[0045] 140, first magnetic flux arrangement slot;

[0046] 150, second magnetic flux arrangement slot;

[0047] 160, cut edge groove;

[0048] 170, shaft hole;

[0049] 181, positioning portion; 182, limiting portion;

[0050] 210, first permanent magnet; 211, first pole surface; 220, second permanent magnet; 221, second pole surface; 230, third permanent magnet; 231, first inclined wedge surface; 232, second inclined wedge surface; 240, fourth permanent magnet; 241, third inclined wedge surface; 242, fourth inclined wedge surface;

[0051] 300, stator. DETAILED DESCRIPTION

[0052] The present application will be further described below with reference to the drawings.

[0053] Referring to Figure 1 and Figure 2 As shown, a motor rotor provided by the present invention includes: a rotor core 100, a plurality of permanent magnet slot groups are arranged on the core assembly, the permanent magnet slot group includes a first permanent magnet slot 110, and the first permanent magnet slot 110 is installed with a first permanent magnet 210, a second permanent magnet 220, a third permanent magnet 230 and a fourth permanent magnet 240.

[0054] Continue to see Figure 3 and Figure 4 As shown, the first permanent magnet slot 110 includes a first slot section 111 and a second slot section 112 spaced apart from each other, the first permanent magnet 210 is installed in the first slot section 111, and the second permanent magnet 220 is installed in the second slot section 112. The first permanent magnet 210 has a first pole face 211 facing the second slot section 112, and the second permanent magnet 220 has a second pole face 221 facing the first slot section 111.

[0055] See also Figure 2 and Figure 3 As shown, the first permanent magnet 210 and the second permanent magnet 220 are combined to form a V-shaped structure. Compared with installing a single type of permanent magnet in the rotor core 100, arranging them into a V-shaped structure can increase the amount of permanent magnets used, thereby increasing the magnetic field strength of the motor rotor.

[0056] See also Figure 1 and Figure 4 As shown, the first permanent magnet slot 110 also includes a third slot segment 113 connecting the first slot segment 111 with the second slot segment 112, and a third permanent magnet 230 is installed in the third slot segment 113. The first end of the third permanent magnet 230 abuts the first pole face 211, and the second end of the third permanent magnet 230 abuts the second pole face 221.

[0057] Since the first end of the third permanent magnet 230 abuts the first pole surface 211 of the first permanent magnet 210, it is equivalent to providing a protruding structure made of permanent magnetic material protruding outward from the first pole surface 211, thereby increasing the thickness of the first permanent magnet 210 at the first pole surface 211 and improving the anti-demagnetization ability of the first permanent magnet 210.

[0058] Similarly, since the second end of the third permanent magnet 230 abuts the second pole surface 221 of the second permanent magnet 220, it is equivalent to providing a protruding structure made of permanent magnetic material protruding outward at the second pole surface 221, thereby increasing the thickness of the second permanent magnet 220 at the second pole surface 221 and improving the anti-demagnetization ability of the second permanent magnet 220.

[0059] Furthermore, because the opposite ends of the third permanent magnet 230 abut against the first permanent magnet 210 and the second permanent magnet 220, respectively, the magnetic flux density between the first permanent magnet 210 and the second permanent magnet 220 is increased. This reduces magnetic flux leakage between the first permanent magnet 210 and the second permanent magnet 220, improves the sinusoidality of the magnetic flux density, reduces higher harmonic content, and improves operational balance.

[0060] See also Figure 1 and Figure 4 As shown, in some implementations, the first permanent magnet 210 and the second permanent magnet 220 are arranged at an angle, and the gap between the first permanent magnet 210 and the second permanent magnet 220 gradually increases in the radial direction (d-axis direction), and the distance between the inner end of the first permanent magnet 210 (the end pointing to the center of the rotor core 100) and the inner end of the second permanent magnet 220 (the end pointing to the center of the rotor core 100) is a first length ( Figure 5 L5 in the figure), the radial outer side surface of the third permanent magnet 230 is in contact with the inner wall of the third slot segment 113, the third permanent magnet 230 is located between the first permanent magnet 210 and the second permanent magnet 220, and the length of the third permanent magnet 230 along the tangential direction of the rotor core 100 (the direction perpendicular to the d-axis) is greater than the first length.

[0061] That is, the first permanent magnet 210 and the second permanent magnet 220 form a V-shaped structure, with the tip of the V-shaped structure pointing toward the center of the rotor core 100's rotation axis. Because the third permanent magnet 230's length along the tangential direction of the rotor core 100 is greater than the first length, the third permanent magnet 230 is prevented from radially passing through the gap between the first permanent magnet 210 and the second permanent magnet 220, thereby limiting the position of the third permanent magnet 230 and preventing it from moving inward. Furthermore, because the radially outer side of the third permanent magnet 230 abuts against the inner wall of the third slot segment 113, the third permanent magnet 230 is prevented from moving outward. In other words, the cooperation between the first permanent magnet 210, the second permanent magnet 220, and the inner wall of the third slot segment 113 ensures the third permanent magnet 230 is limited. During the installation process, one of the first permanent magnet 210 and the second permanent magnet 220 can be installed in the corresponding slot body first, and then the third permanent magnet 230 can be inserted into the third slot section 113. Finally, the permanent magnet that is not installed between the first permanent magnet 210 and the second permanent magnet 220 can be inserted into the corresponding slot body to limit the third permanent magnet 230.

[0062] It is understood that when creating permanent magnet mounting slots in the rotor core 100, not only the arrangement of the permanent magnets must be considered, but also stress concentration on the sidewalls of the slots must be minimized. As shown in the figure, since the third permanent magnet 230 abuts against the permanent magnets at its two opposite tangential ends, this prevents the third permanent magnet 230 from abutting against the inner wall of the slots in the rotor core 100 at its two opposite tangential ends.

[0063] Since the third permanent magnet 230's two opposite tangential ends (the first end and the second end) are not in close contact with the inner wall of the third slot segment 113, that is, the third permanent magnet 230 does not tangentially press the rotor core 100, the tangential pressing force of the third permanent magnet 230 can be transmitted to the rotor core 100 through the first permanent magnet 210 or the second permanent magnet 220. As can be seen from the figure, the first permanent magnet 210 and the second permanent magnet 220 have a larger contact surface with the rotor core 100 in the tangential direction. Compared with direct contact between the rotor core 100 and the first end or the second end of the third permanent magnet 230, this avoids stress concentration on the rotor core 100 and extends the life of the rotor core 100.

[0064] In some implementations, the first permanent magnet 210 and the second permanent magnet 220 can be made of magnetic steel, specifically Alnico magnets, ferrite magnets, NdFeB magnets, or sintered NdFeB magnets. NdFeB magnets are preferably used for the first permanent magnet 210 and the second permanent magnet 220, as they have higher magnetic properties, remanence, and coercive force.

[0065] See also Figure 3 As shown, the first end of the third permanent magnet 230 is provided with a first oblique wedge surface 231, and the second end of the third permanent magnet 230 is provided with a second oblique wedge surface 232. The first oblique wedge surface 231 is in contact with and abuts the first pole surface 211, and the second oblique wedge surface 232 is in contact with and abuts the second pole surface 221.

[0066] That is, the inclination angle of the inclined surface at the first end corresponds to the inclination angle of the first permanent magnet 210 , so that the first wedge surface 231 can have a larger contact area with the first permanent magnet 210 , thereby avoiding concentrated stress between the first permanent magnet 210 and the second permanent magnet 220 .

[0067] See also Figure 3 As shown, because the first end of the third permanent magnet 230 is attached to the side of the first permanent magnet 210 facing the second slot segment 112, and the second end of the third permanent magnet 230 is attached to the side of the second permanent magnet 220 facing the first slot segment 111, and the first permanent magnet 210 and the second permanent magnet 220 are arranged at an angle, the cross-section of the tangentially extending third permanent magnet 230 is trapezoidal. Specifically, because the first permanent magnet 210 and the second permanent magnet 220 are symmetrical along the tangentially extending d-axis, and the tangentially extending third permanent magnet 230 is perpendicular to the d-axis, the trapezoidal cross-section of the third permanent magnet 230 is an isosceles trapezoidal structure. Furthermore, because the spacing between the first permanent magnet 210 and the second permanent magnet 220 gradually increases in the radial direction, the trapezoidal cross-section of the third permanent magnet 230 needs to be set so that the radially outer side is longer than the radially inner side.

[0068] See also Figure 3As shown, in some implementations, a fourth permanent magnet 240 is further installed in the third slot segment 113 and is spaced apart from the third permanent magnet 230. The fourth permanent magnet 240 is located on a side of the third permanent magnet 230 that is close to the center of the rotor core 100, and the inner side surface of the fourth permanent magnet 240 is in contact with the inner wall of the second slot segment 112.

[0069] A third bevel surface 241 is provided at one end of the fourth permanent magnet 240 , and the third bevel surface 241 abuts against the inner end surface of the first permanent magnet 210 . A fourth bevel surface 242 is provided at the other end of the fourth permanent magnet 240 , and the fourth bevel surface 242 abuts against the inner end surface of the second permanent magnet 220 .

[0070] In other words, the third slot segment 113 is not only equipped with at least two permanent magnets (the third permanent magnet 230 and the fourth permanent magnet 240). In addition, the opposite ends of the fourth permanent magnet 240 also abut against the first permanent magnet 210 and the second permanent magnet 220, respectively. In other words, the fourth permanent magnet 240 can also improve the anti-demagnetization ability of the first permanent magnet 210 and the second permanent magnet 220. In extreme working conditions, even if one of the third permanent magnet 230 or the fourth permanent magnet 240 demagnetizes, the other can be used to reduce the demagnetization risk of the first permanent magnet 210 and the second permanent magnet 220, thereby avoiding significant changes in the magnetic field environment of the rotor and affecting the performance of the rotor.

[0071] Furthermore, because the opposing ends of the fourth permanent magnet 240 abut against the inner end surface of the first permanent magnet 210 or the inner end surface of the second permanent magnet 220, the first permanent magnet 210 can radially position the end of the fourth permanent magnet 240 provided with the third beveled wedge surface 241, thereby pressing the fourth permanent magnet 240 radially inward, and preventing the end of the fourth permanent magnet 240 provided with the third beveled wedge surface 241 from moving toward a side away from the center of the rotor core 100. Similarly, the second permanent magnet 220 can radially position the end of the fourth permanent magnet 240 provided with the fourth beveled wedge surface 242, thereby pressing the fourth permanent magnet 240 radially inward, and preventing the end of the fourth permanent magnet 240 provided with the fourth beveled wedge surface 242 from moving toward a side away from the center of the rotor core 100. The inner side surface of the fourth permanent magnet 240 is in contact with the inner wall of the third slot segment 113 , and the inner wall of the rotor core 100 at the third slot segment 113 can prevent the fourth permanent magnet 240 from moving radially inward.

[0072] That is, through the cooperation of the first permanent magnet 210 , the second permanent magnet 220 and the third slot segment 113 , the fourth permanent magnet 240 can be limited radially inwardly and outwardly, thereby keeping the fourth permanent magnet 240 at a specific position.

[0073] according to Figure 2 and Figure 3It can be seen that the first permanent magnet 210 and the second permanent magnet 220 can press the third permanent magnet 230 radially outward against the inner wall of the third slot segment 113, and the first permanent magnet 210 and the second permanent magnet 220 can also press the fourth permanent magnet 240 radially inward against the inner wall of the third slot segment 113. As a result, the third permanent magnet 230 and the fourth permanent magnet 240 are pressed in two opposite directions in the third slot segment 113, forming a hole structure in the second slot segment 112. Compared to manufacturing the third permanent magnet 230 and the fourth permanent magnet 240 as one body, the thickness of the permanent magnets in the third slot segment 113 is increased without increasing the amount of permanent magnet material used, thereby improving the thickness of the third permanent magnet 230 in the third slot segment 113 and the demagnetization resistance of the permanent magnets in the third slot segment 113.

[0074] Before inserting the third permanent magnet 230 and the fourth permanent magnet 240 into the third slot segment 113, the first permanent magnet 210 is first inserted into the first slot segment 111, and the second permanent magnet 220 is inserted into the second slot segment 112. Then, the outer side surface of the third permanent magnet 230 is fitted against the inner wall of the third slot segment 113, and the inner side surface of the fourth permanent magnet 240 is fitted against the inner wall of the third slot segment 113. The first pole surface 211 of the first permanent magnet 210 and the second pole surface 221 of the second permanent magnet 220 are used to prevent the third permanent magnet 230 from moving radially inward, and the inner end surface of the first permanent magnet 210 and the inner end surface of the second permanent magnet 220 are used to prevent the fourth permanent magnet 240 from moving radially outward, thereby achieving radial positioning of the third permanent magnet 230 and the fourth permanent magnet 240.

[0075] See also Figure 2 and Figure 3 As shown, the third permanent magnet 230 and the fourth permanent magnet 240 both extend in a straight line, and the third permanent magnet 230 and the fourth permanent magnet 240 are parallel to each other. Because the third permanent magnet 230 and the fourth permanent magnet 240 extend in a straight line and are arranged in parallel, when designing the third slot segment 113, the third slot segment 113 can be configured as a strip structure with uniform width, reducing the difficulty of processing the third slot segment 113. Specifically, by providing the third slot segment 113 perpendicular to the d-axis direction of the permanent magnet slot group, the third permanent magnet 230 and the fourth permanent magnet 240 that are in contact with the inner wall of the third slot segment 113 can both extend in a straight line in a direction perpendicular to the d-axis direction of the permanent magnet slot group. In other implementations, the extension direction of the third slot segment 113 can be set at an angle to the d-axis direction of the permanent magnet slot group, so that the extension direction of the third permanent magnet 230 and the fourth permanent magnet 240 that are in contact with the inner wall of the third slot segment 113 forms an acute angle with respect to the d-axis direction of the permanent magnet slot group.

[0076] See also Figure 7 As shown, the width of the third slot segment 113 along the d-axis direction is h3, the third permanent magnet 230 has a width of d3 in the d-axis direction, and the fourth permanent magnet 240 has a width of d4 in the d-axis direction, wherein h3 d3+d4. After the third permanent magnet 230 and the fourth permanent magnet 240 are simultaneously inserted into the third slot segment 113, a gap is left in the third slot segment 113, which improves the anti-demagnetization capability of the combination of the third permanent magnet 230 and the fourth permanent magnet 240.

[0077] In some implementations, the widths of the third permanent magnet 230 and the fourth permanent magnet 240 in the d-axis direction are equal, i.e., d3=d4.

[0078] Referring to the drawings, in some implementations, the included angle between the first slot segment 111 and the third slot segment 113 is φ1, wherein 135°≤φ1≤155°. Specifically, φ1 refers to the included angle between the inner wall of the first slot segment 111 facing the second slot segment 112 and the third slot segment 113.

[0079] In some implementations, the first slot segment 111 and the second slot segment 112 are symmetrical along the d-axis of the permanent magnet slot group, and the extension direction of the third slot segment 113 is perpendicular to the d-axis of the permanent magnet slot group. It can be understood that, since the first slot segment 111 and the second slot segment 112 are symmetrical along the d-axis, the included angle between the second slot segment 112 and the third slot segment 113 is equal to the included angle between the first slot segment 111 and the third slot segment 113, i.e., the included angle between the second slot segment 112 and the third slot segment 113 is also φ1.

[0080] wherein the included angle between the inner wall of the inner end of the first slot segment 111 and the third slot segment 113 is φ2. In some implementations, the cross-sectional shape of the first slot segment 111 is rectangular, i.e., the inner wall of the inner end of the first slot segment 111 and the inner wall of the first slot segment 111 facing the second slot segment 112 are perpendicular to each other, that is, φ1+φ2=270°. In some implementations, in order to reduce the processing difficulty of the first permanent magnet slot 110 and ensure the main magnetic flux of the motor permanent magnet, φ1 and φ2 satisfy the formula: 0.8≤φ2 / φ1≤1, i.e., 135°≤φ1≤150°.

[0081] Referring to Figure 6As shown, the rotor core 100 has protruding positioning portions 181 formed at opposite ends of the inner sidewall of the third slot segment 113, and the inner end portion of the first permanent magnet 210 abuts against the side of one of the positioning portions 181, while the inner end face of the second permanent magnet 220 abuts against the side of the other positioning portion 181. In other words, a portion of the inner end face of the first permanent magnet 210 abuts against the side of the positioning portion 181, while another portion abuts against the third beveled wedge surface 241 of the fourth permanent magnet. Similarly, a portion of the inner end face of the second permanent magnet 220 abuts against the side of the positioning portion 181, while another portion abuts against the fourth beveled wedge surface 242 of the fourth permanent magnet. In other words, by forming two protruding positioning portions 181 in the first permanent magnet slot, the first permanent magnet 210 and the second permanent magnet 220 can be positioned.

[0082] See also Figure 6 As shown, the rotor core is further provided with protruding limiting portions 182 at opposite ends of the outer side wall of the third slot segment 113, and the outer tips of the third permanent magnet 230 at both tangential ends abut against the limiting portions 182. That is, the third permanent magnet 230 is limited not only by the first permanent magnet 210 and the second permanent magnet 220, but also by the protruding limiting portions 182.

[0083] See also Figure 2 as well as Figure 3 As shown, in some implementations, the first permanent magnet 210 and the second permanent magnet 220 are symmetrical along a first straight line (coinciding with the d-axis), the first straight line passes through the center of the rotation axis of the rotor core 100 along the radial direction of the rotor core 100, and the third permanent magnet 230 is perpendicular to the first straight line, and the third permanent magnet 230 is symmetrical along the first straight line.

[0084] Because the first permanent magnet 210 and the second permanent magnet 220 are symmetrical along a first radially extending straight line, the combined magnetic fields of the first permanent magnet 210 and the second permanent magnet 220 can be along the first straight line. The third permanent magnet 230 is perpendicular to the first straight line, and the direction of the magnetic field generated by the third permanent magnet 230 is also along the first straight line. In other words, through the above arrangement, the direction of the combined magnetic field of the first permanent magnet 210, the second permanent magnet 220, and the third permanent magnet 230 can be along the radial direction (the first straight line), ensuring the main magnetic flux of the motor permanent magnets.

[0085] It can be understood that the fourth permanent magnet 240 is also perpendicular to the first straight line and symmetrical along the first straight line, that is, the magnetic fields of the four permanent magnets in the first permanent magnet slot 110 are combined and directed along the first straight line.

[0086] See also Figure 2 and Figure 3As shown, in some implementations, the first permanent magnet 210 and the second permanent magnet 220 are symmetrical along a first line, the permanent magnet slot group further includes a second permanent magnet slot 120 and a third permanent magnet slot 130 symmetrically along the first line, the second permanent magnet slot 120 and the third permanent magnet slot 130 are both located radially outward of the third slot segment 113, and the rotor core 100 is further provided with a magnetic flux alignment slot between the second permanent magnet slot 120 and the third permanent magnet slot 130. Because the second permanent magnet slot 120 and the third permanent magnet slot 130 are provided radially outward of the third slot segment 113, the permanent magnets in the second permanent magnet slot 120 and the third permanent magnet slot 130 can be used to increase the magnetic flux density of the rotor, thereby guiding the stator magnetic field and reducing magnetic flux leakage.

[0087] By setting a magnetic flux sorting slot between the second permanent magnet slot 120 and the third permanent magnet slot 130, the air in the magnetic flux sorting slot is used to increase the magnetic resistance at the magnetic flux sorting slot, thereby reducing the magnetic flux lines passing through the magnetic flux sorting slot and guiding the magnetic flux lines to the first permanent magnet slot 110, thereby ensuring the main magnetic flux of the permanent magnet of the motor.

[0088] See also Figure 5 As shown, the second permanent magnet slot 120 includes a fourth slot segment 121 and a fifth slot segment 122. Permanent magnets are installed in each of the fourth slot segment 121 and the fifth slot segment 122. The fifth slot segment 122 is parallel to the second slot segment 112. The fourth slot segment 121 and the fifth slot segment 122 are arranged at an angle. One end of the fourth slot segment 121 is connected to the fifth slot segment 122, and the other end of the fourth slot segment 121 extends toward the outer edge of the rotor core 100. By arranging the fifth slot segment 122 parallel to the second slot segment 112 and installing permanent magnets in the fifth slot segment 122, the magnetic field strength at the second slot segment 112 can be increased. By extending the end of the fourth slot segment 121 away from the fifth slot segment 122 toward the outer edge of the rotor core 100, the magnetic field strength at the outer edge of the rotor core 100 at the fifth slot segment 122 can be increased, thereby avoiding magnetic flux leakage in the fifth slot segment 122 region and improving the utilization rate of the permanent magnets.

[0089] See also Figure 5 As shown, the length of the permanent magnet in the fifth slot segment 122 is greater than that of the permanent magnet in the fourth slot segment 121. This can increase the air gap flux density at the fifth slot segment 122, thereby effectively utilizing the magnetic field of the permanent magnet and maximizing the output torque capacity of the motor.

[0090] In some implementations, the fifth slot segment 122 is perpendicular to the fourth slot segment 121 , and an extending direction of the fifth slot segment 122 is parallel to the first straight line.

[0091] See also Figure 4As shown, in some implementations, the outer edge of the rotor core 100 is provided with multiple slicing grooves. The number of slicing grooves 160 is equal to the number of permanent magnet slot groups, and one slicing groove 160 is provided between every two adjacent permanent magnet slot groups. In other words, the slicing grooves 160 are provided at the q-axis of the permanent magnet slot groups, which can reduce the impact of back-EMF peaks on the motor.

[0092] It is understandable that the rotor core 100 is provided with a plurality of permanent magnet slot groups evenly distributed along the circumferential direction, wherein the number of permanent magnet slot groups can be selected according to the actual working conditions of the motor rotor. Figure 4 As shown, six permanent magnet slot groups are evenly distributed along the circumferential direction on the rotor core 100 .

[0093] In order to more clearly illustrate the technical solution of the present application, a specific implementation scheme using the motor rotor of the present application is described in detail below.

[0094] See also Figure 4 As shown, six permanent magnet slot groups are provided on the rotor core 100, including a first permanent magnet slot 110, a second permanent magnet slot 120, and a third permanent magnet slot 130. The first permanent magnet slot 110 is generally U-shaped. The first permanent magnet slot 110 includes a first slot section 111, a third slot section 113, and a second slot section 112, which are connected in sequence. A first permanent magnet 210 is mounted in the first slot section 111, a second permanent magnet 220 is mounted in the second slot section 112, and a third permanent magnet 230 and a fourth permanent magnet 240 are mounted in the third slot section 113.

[0095] The length of the first permanent magnet 210 and the length of the second permanent magnet 220 are both L3, and in this embodiment, 8mm≤L3≤10mm. The thickness of the first permanent magnet 210 and the second permanent magnet 220 is d2, and in this embodiment, 1.4mm≤d2≤1.7mm. The first permanent magnet 210 and the second permanent magnet 220 are arranged at an angle and are symmetrical along the d axis of the permanent magnet slot group. The distance (first length) between the inner end of the first permanent magnet 210 and the inner end of the second permanent magnet 220 is L4, and in this embodiment, 8mm≤L4≤10mm.

[0096] The third slot section 113 is set to a trapezoidal structure to connect the first slot section 111 and the second slot section 112 on both sides, and the length of the inner wall of the third slot section 113 arranged radially outward is L5. In this embodiment, 12mm≤L5≤14mm.

[0097] By setting the length of the third permanent magnet 230 to L5 and setting the inclination angles of the inclined surfaces on both sides of the third permanent magnet 230 according to the angle between the first permanent magnet 210 and the second permanent magnet 220, when the third permanent magnet 230 is installed in the third slot segment 113, the first beveled wedge surface 231 at the first end of the third permanent magnet 230 abuts against the first permanent magnet 210, and the second beveled wedge surface 232 at the second end of the third permanent magnet 230 abuts against the second permanent magnet 220. The radial outer side surface of the third permanent magnet 230 abuts against the inner wall of the third slot segment 113.

[0098] The fourth permanent magnet 240 in the third slot section 113 is also configured with a trapezoidal cross-section, with the inner side (the side closer to the rotor center) of the trapezoidal cross-section of the fourth permanent magnet 240 being longer than the outer side (the side farther from the rotor center). This ensures that both ends of the fourth permanent magnet 240 are retained in the third slot section 113 by the abutment of the inner ends of the first permanent magnet 210 and the second permanent magnet 220, while the inner side of the fourth permanent magnet 240 is pressed against the inner wall of the third slot section 113.

[0099] The radial thickness d3 of the third permanent magnet 230 is equal to the radial thickness d4 of the fourth permanent magnet 240. In this embodiment, 1 mm ≤ d3 = d4 ≤ 1.2 mm. The radial gap between the third permanent magnet 230 and the fourth permanent magnet 240 is h3 - d3 - d4. In this embodiment, 0.8 mm ≤ h3 - d3 - d4 ≤ 1 mm.

[0100] The angle between the first pole face 211 (the side of the first permanent magnet 210 facing the second slot segment 112) and the third slot segment 113 is φ1. In this embodiment, 135°≤φ1≤155°. The angle between the inner end face of the first permanent magnet 210 and the third slot segment 113 is φ2. In this embodiment, 120°≤φ2≤130°.

[0101] The third permanent magnet slot 130 and the fourth permanent magnet slot are located radially outward from the third slot segment 113 and are symmetrical about the d-axis of the permanent magnet slot group. The third permanent magnet slot 130 includes a fourth slot segment 121 and a fifth slot segment 122, which are perpendicular to each other. The fifth slot segment 122 is parallel to the third slot segment 113 and extends perpendicular to the d-axis. The fourth slot segment 121 is perpendicular to the fifth slot segment 122 and extends along the d-axis. The thickness of the fourth slot segment 121 and the fifth slot segment 122 is d1. In this embodiment, 0.8 mm ≤ d1 ≤ 1 mm.

[0102] The length L2 of the fourth slot segment 121 is greater than the length L1 of the fifth slot segment 122 . In this embodiment, 3 mm ≤ L1 ≤ 4.2 mm, and 5 mm ≤ L2 ≤ 6 mm.

[0103] See also Figure 4-Figure 6 As shown, two magnetic flux sorting grooves are provided between the second permanent magnet slot 120 and the third permanent magnet slot 130, and both magnetic flux sorting grooves are located radially outward of the third permanent magnet slot 130. The two magnetic flux sorting grooves are symmetrical along the d-axis of the permanent magnet slot group. For convenience of explanation, the magnetic flux sorting groove closer to the second permanent magnet slot 120 is referred to as the first magnetic flux sorting groove 140, and the magnetic flux sorting groove closer to the third permanent magnet slot 130 is referred to as the second magnetic flux sorting groove 150. The distance between the inner end of the first magnetic flux sorting groove 140 and the fourth slot segment 121 is h1, and the distance between the inner end of the first magnetic flux sorting groove 140 and the fifth slot segment 122 is h2. In this embodiment, h1 = h2 ≥ 2 mm.

[0104] See also Figure 7 As shown, a trimming groove 160 is provided on the outer edge of the rotor core 100 . The depth of the trimming groove 160 is q1 . In this embodiment, 1.2 mm ≤ q1 ≤ 1.3 mm.

[0105] See also Figure 8 As shown in the figure, the induced electromotive force of the motor rotor designed according to the above dimensions is optimized to 61.98. Figure 9 , shows the back EMF waveform of the motor rotor before the improvement, showing that the induced EMF of the motor rotor before the improvement is 57.81. In other words, by adopting the motor rotor structure of the present application, the induced EMF of the motor rotor is increased. Comparing the back EMF waveforms before and after the improvement, it can be seen that the back EMF waveform of the improved motor rotor is closer to a sine curve, improving the performance of the motor rotor.

[0106] See also Figure 10 As shown in FIG, the motor efficiency of the improved motor rotor is higher than that of the motor of the prior art. Figure 11 As shown, the demagnetization rate of the motor rotor of the present invention is lower than that of the motor of the prior art at various operating currents. In addition, the demagnetization rate of the motor of the present invention remains below 5% at an operating current of 31A. Compared with the motor of the prior art, the motor of the present invention can be used at higher operating currents and withstand heavier loads. This indicates that the anti-demagnetization capability of the improved motor rotor has been improved.

[0107] A shaft hole 170 extending in the axial direction is provided at the center of the rotor core 100 . A shaft can be installed in the shaft hole 170 to connect with the rotor core 100 .

[0108] In summary, the motor rotor structure designed in this application can not only improve the rotor's anti-demagnetization ability, but also improve the motor's working efficiency, and also improve the motor rotor's back EMF waveform, thereby greatly improving the performance of the motor rotor.

[0109] See also Figure 12In the second aspect, the motor rotor is also provided in the motor. The motor rotor has the advantages of the motor rotor as described above.

[0110] In the third aspect, the motor is also provided in the compressor. The motor has the advantages of the motor as described above.

[0111] In the fourth aspect, the motor is also provided in the household appliance. The motor has the advantages of the motor as described above. The household appliance can be a refrigeration device with a compressor, or a household appliance driven by a motor, such as a fan or a washing machine.

[0112] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to the application without departing from the scope of the application. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A motor rotor, characterized in that: It includes: A rotor core, wherein the rotor core is provided with a plurality of permanent magnet slot groups, the permanent magnet slot groups including a first permanent magnet slot, the first permanent magnet slot including a first slot segment and a second slot segment spaced apart from each other, and a third slot segment connecting the first slot segment and the second slot segment; a first permanent magnet installed in the first slot segment, the first permanent magnet having a first pole surface facing the second slot segment; a second permanent magnet installed in the second slot segment, the second permanent magnet having a second pole face facing the first slot segment; as well as a third permanent magnet installed in the third slot segment, wherein a first end of the third permanent magnet abuts against the first pole surface, and a second end of the third permanent magnet abuts against the second pole surface; The first permanent magnet and the second permanent magnet are arranged at an angle, and the gap between the first permanent magnet and the second permanent magnet gradually increases in the radial direction, and the distance between the inner end of the first permanent magnet and the inner end of the second permanent magnet is a first length; The radial outer side surface of the third permanent magnet is in contact with the inner wall of the third slot segment. The third permanent magnet is located between the first permanent magnet and the second permanent magnet. The length of the third permanent magnet along the tangential direction of the rotor core is greater than the first length. A fourth permanent magnet is further installed in the third slot segment and is spaced apart from the third permanent magnet. The fourth permanent magnet is located on a side of the third permanent magnet close to the center of the rotor core, and an inner side surface of the fourth permanent magnet is in contact with an inner wall of the third slot segment. One end of the fourth permanent magnet is provided with a third bevel surface, which abuts the inner end surface of the first permanent magnet. The other end of the fourth permanent magnet is provided with a fourth bevel surface, which abuts the inner end surface of the second permanent magnet.

2. The motor rotor according to claim 1, characterized in that: The first end of the third permanent magnet is provided with a first oblique wedge surface, and the second end of the third permanent magnet is provided with a second oblique wedge surface. The first oblique wedge surface is in contact with and abuts the first pole surface, and the second oblique wedge surface is in contact with and abuts the second pole surface.

3. The motor rotor according to claim 1, characterized in that: The third permanent magnet and the fourth permanent magnet both extend along a straight line, and the third permanent magnet is parallel to the fourth permanent magnet.

4. The motor rotor according to any one of claims 1 to 3, characterized in that: The included angle between the first slot segment and the third slot segment is φ1, wherein 135°≤φ1≤155°.

5. The motor rotor according to any one of claims 1 to 3, characterized in that: The first permanent magnet and the second permanent magnet are symmetrical along a first straight line, and the first straight line passes through the center of the rotation axis of the rotor core along the radial direction of the rotor core. The third permanent magnet is perpendicular to the first straight line and is symmetrical along the first straight line.

6. The motor rotor according to any one of claims 1 to 3, characterized in that: The first permanent magnet and the second permanent magnet are symmetrical along a first straight line. The permanent magnet slot group also includes a second permanent magnet slot and a third permanent magnet slot that are symmetrical along the first straight line. The second permanent magnet slot and the third permanent magnet slot are both located radially outside the third slot segment, and the rotor core is also provided with a magnetic flux sorting slot between the second permanent magnet slot and the third permanent magnet slot.

7. The motor rotor according to claim 6, characterized in that: The second permanent magnet slot includes a fourth slot segment and a fifth slot segment, wherein permanent magnets are respectively installed in the fourth slot segment and the fifth slot segment, and the fifth slot segment is parallel to the second slot segment; The fourth slot segment is arranged at an angle to the fifth slot segment, one end of the fourth slot segment is connected to the fifth slot segment, and the other end of the fourth slot segment extends toward the outer edge of the rotor core.

8. The motor rotor according to any one of claims 1 to 3, characterized in that: A plurality of trimming grooves are provided on the outer edge of the rotor core. The number of the trimming grooves is equal to the number of the permanent magnet slot groups. Each of the trimming grooves is respectively provided between two adjacent permanent magnet slot groups.

9. A motor, characterized in that: It comprises the motor rotor according to any one of claims 1-8.

10. A compressor, characterized in that: It comprises the motor according to claim 9.

11. A household appliance, characterized in that: It comprises the motor according to claim 9.

Images