Motor rotor assembly, motor, compressor

Abstract

The present invention provides a motor rotor assembly, a motor, and a compressor, wherein the motor rotor assembly includes a rotor core, wherein the rotor core is constructed with two or more first magnetic steel slots extending through the axial ends thereof, wherein a first magnetic steel is installed in the first magnetic steel slot, and the inner walls of the slots at the axial ends of the first magnetic steel slot are provided with first protrusions, and the first protrusions extend from the inside to the outside along the radial direction of the rotor core so as to be able to support the axial ends of the radial inner side surface of the first magnetic steel. According to the present invention, when the first magnetic steel is inserted into the first magnetic steel slot, its two ends are reliably supported by the first protrusions, and a gap is formed between its middle position and the slot wall of the first magnetic steel slot, forming an air magnetic isolation structure. In this way, the air magnetic isolation structure cuts off the leakage magnetic path caused by the connection between the inner end pole portion and the pole portion of the punching sheet, thereby increasing the air gap length, increasing the air gap magnetic resistance, reducing the leakage magnetic flux, and improving the utilization rate of the permanent magnet and the performance of the motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor manufacturing, and in particular relates to a motor rotor assembly, a motor, and a compressor. Background Art

[0002] my country possesses unique advantages for developing efficient, energy-saving rare earth permanent magnet motors. Compared to conventional induction motors, permanent magnet synchronous motors offer advantages such as small size, light weight, and high power density. More importantly, permanent magnet synchronous motors are synchronous motors with rare earth rotors, zero slip, no electrical excitation, and no fundamental copper or aluminum losses. The rotor is excited by permanent magnets, eliminating the need for reactive excitation current. This improves power factor, reduces reactive power, significantly decreases stator current, and significantly reduces stator copper losses.

[0003] Self-starting permanent magnet synchronous motors, due to their numerous advantages, such as high efficiency, high power factor, and high starting torque, are now replacing asynchronous motors in non-regulatory applications. They hold enormous market potential and offer significant economic benefits. The incorporation of a starting winding (squirrel cage bar) end ring structure on the motor rotor enables self-starting, eliminating the need for a starting device, saving costs and achieving high energy efficiency. Incorporating a starting winding (squirrel cage bar) end ring structure into a speed-regulatory permanent magnet synchronous motor can adjust the motor's starting torque and speed, thereby improving its dynamic performance.

[0004] In the existing compressor motor rotor structure, permanent magnets are mostly placed radially and on the surface. During use, the power density and structural strength are low. The tangential structure has problems such as demagnetization, magnetic leakage and structural strength. During long-term operation, the rotor is at risk of deformation and damage.

[0005] Existing compressors use rare earth NdFeB permanent magnet synchronous motors. Rare earths are a key national strategic reserve material. Due to upstream raw material control, rare earth resources are limited. NdFeB is expensive and has significant price fluctuations, increasing procurement risks. Ferrite, on the other hand, is abundant and has a stable price. Various companies are researching motors using ferrite or less rare earth materials to replace high-performance permanent magnet motors made with rare earth materials.

[0006] In permanent magnet motors, the tangential structure with built-in permanent magnets has many advantages over other structures, but the leakage flux is large, resulting in low utilization of permanent magnet materials, which has a significant impact on the permanent magnet's anti-demagnetization ability, motor performance, and weak magnetic speed expansion capability. Therefore, magnetic isolation measures need to be taken. Summary of the Invention

[0007] Therefore, the present invention provides a motor rotor assembly, a motor, and a compressor, which can overcome the shortcomings of the related art in which the utilization rate of permanent magnet materials in the motor with a built-in permanent magnet tangential structure is low, which has a significant impact on the anti-demagnetization ability of the permanent magnet and the motor performance and weak magnetic speed expansion capability.

[0008] In order to solve the above problems, the present invention provides a motor rotor assembly, including a rotor core, wherein the rotor core is constructed with two or more first magnetic steel slots extending through its two axial ends, and the first magnetic steel is installed in the first magnetic steel slot. The inner walls of the slots at the two axial ends of the first magnetic steel slot are provided with first protrusions, and the first protrusions extend from the inside to the outside along the radial direction of the rotor core so as to be supported at the two axial ends of the radial inner side surface of the first magnetic steel.

[0009] In some embodiments, the axial projection of the first protrusion on the radial surface of the rotor core is semicircular; and / or the axial length of the first protrusion in the rotor core is L1, and the axial length of the rotor core is L, 1 / 100≤L1 / L≤1 / 20.

[0010] In some embodiments, the rotor core is further constructed with a plurality of second magnetic steel slots extending through both axial ends thereof, wherein second magnetic steels are installed in the second magnetic steel slots, and the second magnetic steel slots are located radially outward of the first magnetic steel slots and are symmetrical about the same q-axis.

[0011] In some embodiments, the inner walls of the slot at both axial ends of the second magnetic steel slot have second protrusions, and the second protrusions extend from the inside to the outside along the radial direction of the rotor core so as to be supported at both axial ends of the radial inner side surface of the second magnetic steel.

[0012] In some embodiments, the rotor core includes an intermediate core segment and end core segments stacked on both axial ends of the intermediate core segment, the end core segments are stacked by multiple first punching sheets, the first protrusion and the second protrusion are both constructed at corresponding positions of the first punching sheets, the intermediate core segment is stacked by multiple second punching sheets, and the second punching sheets do not have the first protrusion and the second protrusion.

[0013] In some embodiments, the radial length of the first magnetic steel is h11, the circumferential width is w11, the minimum radial spacing of the first magnetic steel slots is h1, the circumferential spacing is w1, h1>h11, w1>w11; and / or, the radial length of the second magnetic steel is h22, the circumferential width is w22, the minimum radial spacing of the second magnetic steel slots is h2, the circumferential spacing is w2, h2>h22, w2>w22.

[0014] In some embodiments, w11>w22 and h11>h22, the first magnetic steel is a ferrite permanent magnet, and the second magnetic steel is a rare earth permanent magnet.

[0015] In some embodiments, the radius of the semicircular first protrusion is R1, 1 / 50≤R1 / h1≤1 / 10; and / or the first magnetic steel slot is symmetrical about the corresponding q axis, and the first protrusion is symmetrical about the q axis.

[0016] In some embodiments, the axial projection of the second protrusion on the radial surface of the rotor core is semicircular; and / or the axial length of the second protrusion of the rotor core is d2, L1=d2; and / or the radius of the semicircular second protrusion is R2, 1 / 50≤R2 / h2≤1 / 10; and / or the second magnetic steel slot is symmetrical about the q axis, and the second protrusion is symmetrical about the q axis.

[0017] In some embodiments, a first magnetic isolation bridge is formed between the radial outer slot wall of the first magnetic steel slot and the radial inner slot wall of the second magnetic steel slot, and the minimum radial thickness of the first magnetic isolation bridge is h4, 0.2mm≤h4; and / or, a second magnetic isolation bridge is formed between the radial inner slot walls of two adjacent first magnetic steel slots in the circumferential direction of the rotor core, and the minimum circumferential width of the second magnetic isolation bridge is h6, 0.2mm≤h6; and / or, a flow hole is provided on the radial inner side of the first magnetic steel slot, and the flow hole is symmetrical about the q axis, and a third magnetic isolation bridge is formed between the radial inner slot wall of the first magnetic steel slot and the radial outer slot wall of the flow hole, and the minimum radial thickness of the third magnetic isolation bridge is h3, 0.2mm≤h3.

[0018] In some embodiments, the outer circumferential wall of the rotor core has a plurality of grooves that are recessed radially inward, each of the grooves is symmetrical about the q axis, and the groove depth decreases from the middle to both sides, and a fourth magnetic isolation bridge is formed between the bottom wall of the groove and the radial outer wall of the second magnetic steel slot, and the minimum radial thickness of the fourth magnetic isolation bridge is h5, 0.2mm≤h5.

[0019] In some embodiments, when the motor rotor assembly is assembled with its corresponding stator assembly, a stator-rotor air gap is formed between the tooth boots of the motor rotor assembly and the stator assembly. At the position corresponding to the groove, the maximum radial width of the stator-rotor air gap is δmax and the minimum radial width is δmin, 1.0mm≤δmax≤1.5mm, 0.4mm≤δmin≤0.8mm.

[0020] In some embodiments, a plurality of open slots are provided in the corresponding area between two adjacent second magnetic steel slots of the rotor core, and the open slots pass through both axial ends of the rotor core along the axial direction, and the open slots are connected to the outer circumferential side of the rotor core through the openings they have.

[0021] In some embodiments, a magnetic isolation strip passes through the open slot, and both ends of the magnetic isolation strip are respectively connected to magnetic isolation end rings.

[0022] In some embodiments, the inner circle of the magnetic isolation end ring has a notch groove corresponding to the position of the second magnetic steel slot, the circumferential width of the notch groove is w4, the circumferential width of the second magnetic steel is w22, and the radial length is h22, w4>w22, and the distance between the radial bottom wall of the notch groove and the radial inner groove wall of the second magnetic steel slot is not less than h22.

[0023] In some embodiments, a balancing block is further connected to the shaft end of the rotor core, and the balancing block is embedded in the inner circle of the magnetic isolation end ring.

[0024] The present invention also provides a motor, comprising the motor rotor assembly described above.

[0025] The present invention also provides a compressor comprising the above-mentioned motor rotor assembly.

[0026] The present invention provides a motor rotor assembly, motor, and compressor, in which the first protrusion is only arranged at the slot positions at the axial ends of the first magnetic steel slot, and the first protrusion is not arranged on the slot wall therebetween. In this way, when the first magnetic steel is inserted into the first magnetic steel slot, its two ends are reliably supported by the first protrusion, and a gap is formed between its middle position and the slot wall of the first magnetic steel slot, forming an air magnetic isolation structure. In this way, the air magnetic isolation structure cuts off the leakage magnetic circuit caused by the connection between the internal end poles of the punching sheet and the poles inside the punching sheet, increases the air gap length, increases the air gap magnetic resistance, reduces leakage magnetic flux, and improves the utilization rate of the permanent magnet and the performance of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the disassembled structure of a motor rotor assembly according to an embodiment of the present invention (without a squirrel cage structure);

[0028] Figure 2 for Figure 1 A schematic diagram of a radial cross section of a motor rotor assembly;

[0029] Figure 3 for Figure 1 A schematic diagram of an axial cross section of a motor rotor assembly;

[0030] Figure 4 This is a schematic diagram of the disassembled structure of a motor rotor assembly (with a squirrel cage structure) according to another embodiment of the present invention;

[0031] Figure 5 for Figure 4 A schematic diagram of a radial cross section of a motor rotor assembly;

[0032] Figure 6 for Figure 4 Schematic diagram of a radial cross section of the squirrel cage structure;

[0033] Figure 7 This is a schematic diagram of an axial projection of a first punching plate in one embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of an axial projection of a second punching plate in one embodiment of the present invention;

[0035] Figure 9 is a schematic axial projection diagram of a first punching plate in another embodiment of the present invention;

[0036] Figure 10 is a schematic axial projection diagram of a second punching plate in another embodiment of the present invention;

[0037] Figure 11 FIG. 1 is a partial diagram illustrating the relative positional relationship between the stator assembly and the rotor assembly in a motor according to another embodiment of the present invention.

[0038] The reference numerals indicate:

[0039] 1. Rotor core; 101. First punching sheet; 102. Second punching sheet; 11. First magnetic steel slot; 111. First protrusion; 12. Second magnetic steel slot; 121. Second protrusion; 13. Through hole; 14. Groove; 15. Open slot; 21. First magnetic steel; 22. Second magnetic steel; 31. Magnetic isolation guide bar; 32. Magnetic isolation end ring; 321. Notched slot; 4. Balancing block; 100. Stator assembly; 200. Rotor assembly. DETAILED DESCRIPTION

[0040] See also Figures 1 to 11As shown, according to an embodiment of the present invention, a motor rotor assembly is provided, including a rotor core 1. The rotor core 1 is configured with two or more first magnetic steel slots 11 that pass through its axial ends. First magnetic steels 21 are installed in the first magnetic steel slots 11. The inner walls of the slots at the axial ends of the first magnetic steel slots 11 are provided with first protrusions 111. The first protrusions 111 extend from the inside to the outside along the radial direction of the rotor core 1 so as to be supported at the axial ends of the radial inner side surface of the first magnetic steel 21. In this technical solution, the first protrusion 111 is only arranged at the slot positions at the axial ends of the first magnetic steel slot 11, and the first protrusion 111 is not arranged on the slot wall therebetween. In this way, when the first magnetic steel 21 is inserted into the first magnetic steel slot 11, its two ends are reliably supported by the first protrusion 111, and a gap is formed between its middle position and the slot wall of the first magnetic steel slot 11, forming an air magnetic isolation structure. In this way, the air magnetic isolation structure cuts off the leakage magnetic circuit caused by the connection between the internal end poles and the poles of the punching sheet, increases the air gap length, increases the air gap magnetic resistance, reduces the leakage magnetic flux, and improves the utilization rate of the permanent magnet and the performance of the motor.

[0041] In some embodiments, the axial projection of the first protrusion 111 on the radial surface of the rotor core 1 is semicircular. Theoretically, the semicircular first protrusion 111 only makes linear contact with the radially inner surface of the first magnetic steel 21 along the axial direction of the rotor core 1. This increases the radial thickness of the air-magnetic shielding structure, further increasing the air gap magnetic resistance and reducing magnetic leakage. The axial length of the first protrusion 111 in the rotor core 1 is L1. The axial length of the rotor core 1 is L, and 1 / 100 ≤ L1 / L ≤ 1 / 20. A first protrusion 111 of a reasonable length can balance the support strength and stability of the first magnetic steel 21 with maximizing the axial length of the air-magnetic shielding structure.

[0042] In some embodiments, the rotor core 1 is further constructed with a plurality of second magnetic steel slots 12 extending through both axial ends thereof, and second magnetic steels 22 are installed in the second magnetic steel slots 12. The second magnetic steel slots 12 are radially outward of the first magnetic steel slots 11 and symmetrical about the same q-axis. At this time, the first magnetic steel 21 and the second magnetic steel 22 are arranged tangentially, which can improve the torque density, the dual-magnetic source series magnetic circuit rotor structure, the small magnetic circuit magnetic resistance, the maximum utilization rate of the permanent magnet, and the saving of the permanent magnet cost. It is possible to achieve the optimal ratio of the permanent magnets, maximize the efficiency at low cost, optimize the magnetic circuit, and maximize the efficiency of the motor. For example, the first magnetic steel 21 and the second magnetic steel 22 can be respectively selected from ferrite and rare earth permanent magnets for combination, which can improve the anti-demagnetization ability and reduce the amount of rare earth; the second magnetic steel 22 uses rare earth permanent magnets, while the first magnetic steel 21 uses ferrite permanent magnets, which can improve the utilization rate of rare earth.

[0043] As a specific implementation, the rotor core 1 includes an intermediate core segment and end core segments stacked on both axial ends of the intermediate core segment. The end core segments are formed by stacking a plurality of first punching sheets 101. The first protrusions 111 and the second protrusions 121 are both constructed at corresponding positions on the first punching sheets 101. The intermediate core segment is formed by stacking a plurality of second punching sheets 102. The second punching sheets 102 do not have the first protrusions 111 and the second protrusions 121. The number of stacked punching sheets in each core segment can be reasonably selected according to actual needs. The first punching sheets 101 and the second punching sheets 102 can be formed by stamping an electrical steel strip (plate) with a thickness of 0.25 mm, 0.3 mm, 0.35 mm, or 0.5 mm.

[0044] The first magnetic steel 21 has a radial length of h11 and a circumferential width of w11. The first magnetic steel slots 11 have a minimum radial spacing of h1 and a circumferential spacing of w1, where h1>h11 and w1>w11. Alternatively, the second magnetic steel 22 has a radial length of h22 and a circumferential width of w22. The second magnetic steel slots 12 have a minimum radial spacing of h2 and a circumferential spacing of w2, where h2>h22 and w2>w22. This allows for a small gap between the first and second magnetic steels 21, 22, and their corresponding magnetic steel slots, facilitating the magnetic steel insertion process.

[0045] As a preference, w11>w22 and h11>h22, the first magnetic steel 21 is a ferrite permanent magnet, and the second magnetic steel is a rare earth permanent magnet (mainly NdFeB). In this case, the amount of rare earth used will be less than that of ferrite, thereby saving the manufacturing cost of the motor. Of course, in some cases w11 and w22 can also be designed to be equal, such as Figure 9 and Figure 10 If the second magnetic steel 22 is a rare earth permanent magnet, w22 is usually selected from 1.5mm to 3.5mm, and h22 is usually selected from 15mm to 30mm; if the first magnetic steel 21 is a ferrite permanent magnet, w22 is usually selected from 3.0mm to 5.5mm, and h22 is usually selected from 20mm to 35mm.

[0046] In some embodiments, the radius of the semicircular first protrusion 111 is R1, 1 / 50≤R1 / h1≤1 / 10, which increases the distance between the bottom surface of the permanent magnet (radially inner side) and the wall of the slot hole (radially inner wall) where the permanent magnet is placed, thereby making the size of the air gap within a reasonable range. The larger the air gap, the better the anti-magnetic leakage and magnetic isolation effects. However, if the air gap is too large, the radial size of the rotor will be increased. When the rotor size increases, the stator size will be reduced while the overall size of the motor remains unchanged, affecting the motor performance. The first magnetic steel slot 11 is symmetrical about the corresponding q axis, and the first protrusion 111 is symmetrical about the q axis, which can ensure stable support for the first magnetic steel 21.

[0047] Preferably, the second magnetic steel slot 12 has second protrusions 121 on the inner walls of the slot at both axial ends. The second protrusions 121 extend radially from the inside to the outside of the rotor core 1 to support the radially inner side surfaces of the second magnetic steel 22 at both axial ends. Specifically, the axial projection of the second protrusion 121 on the radial surface of the rotor core 1 is semicircular. The axial length of the second protrusion 121 on the rotor core 1 is d2, where L1 = d2. The radius of the semicircular second protrusion 121 is R2, where 1 / 50 ≤ R2 / h2 ≤ 1 / 10. The second magnetic steel slot 12 is symmetrical about the q axis, and the second protrusion 121 is symmetrical about the q axis. The beneficial effects brought about by this are the same as those of providing the first protrusion 111 and will not be repeated here.

[0048] In the permanent magnet tangential combination structure, when the rotor structure rotates with the shaft, the first magnetic steel 21, the second magnetic steel 22 and the mass of the rotor core 1 itself will generate centrifugal force. The width of the relevant magnetic isolation bridge on the rotor core 1 is reasonably selected to reduce the impact of the centrifugal force on the magnetic isolation bridge and the overall strength of the rotor. Based on this technical purpose, in some embodiments, a first magnetic isolation bridge is formed between the radially outer slot wall of the first magnetic steel slot 11 and the radially inner slot wall of the second magnetic steel slot 12, and the minimum radial thickness of the first magnetic isolation bridge is h4, 0.2mm≤h4≤1.5mm; and / or, a second magnetic isolation bridge is formed in the circumferential direction of the rotor core 1 between the radially inner slot walls of two adjacent first magnetic steel slots 11, and the minimum circumferential width of the second magnetic isolation bridge is h6, 0. 2mm≤h6≤1.5mm; and / or, a flow hole 13 is provided on the radial inner side of the first magnetic steel slot 11, and the flow hole 13 is symmetrical about the q axis, and a third magnetic isolation bridge is formed between the radial inner slot wall of the first magnetic steel slot 11 and the radial outer slot wall of the flow hole, and the minimum radial thickness of the third magnetic isolation bridge is h3, 0.2mm≤h3≤1.5mm; in some embodiments, the outer circumferential wall of the rotor core 1 has a plurality of grooves 14 that are recessed radially inward, each groove 14 is symmetrical about the q axis, and its groove depth becomes smaller from the middle to both sides, and a fourth magnetic isolation bridge is formed between the bottom wall of the groove 14 and the radial outer slot wall of the second magnetic steel slot 12, and the minimum radial thickness of the fourth magnetic isolation bridge is h5, 0.2mm≤h5≤1.5mm. The aforementioned flow hole 13 is preferably a waist-shaped arc hole. Under the premise of meeting the requirements of electromagnetic performance and manufacturing process, the stress analysis of the rotor as a whole is carried out under the action of centrifugal force when the compressor motor is running at the highest speed. While ensuring the structural strength, the optimal magnetic isolation size is obtained to optimize the motor performance, optimize the design of the flow hole 13, and increase the rotor flow area.

[0049] In addition, the arrangement of the aforementioned groove 14 makes the d-axis and q-axis of the rotor assembly unequal in length. In the built-in tangential structure, by rationally designing the thickness and width of the permanent magnet size in the magnetization direction, the rotor punching structure is trimmed and improved by adding magnetic isolation holes. The magnetic permeability of the permanent magnet is low, basically close to that of air, while the rotor punching is a silicon steel sheet with a higher magnetic permeability. Due to the difference in the armature reaction flux paths of the d and q axes in the rotor, the magnetic circuit structure of the permanent magnet in the rotor is asymmetric, and the d-axis magnetic resistance is greater than the q-axis magnetic resistance, thereby increasing the difference in the dq-axis inductance of the motor, thereby increasing the magnetic resistance torque output by the motor, and improving the power density, constant power operating range and weak magnetic expansion speed of the motor. The synthetic formula of the resistance torque and the permanent magnet torque is as follows:

[0050] T=mp(L q -L d )i d i a +mpψ PM l q , where the first term is the reluctance torque and the second term is the permanent magnet torque. Ld, Lq, id, and iq are the d-axis and q-axis inductances and currents, respectively.

[0051] In some embodiments, when the motor rotor assembly is assembled with the stator assembly 100 corresponding thereto, a stator-rotor air gap is formed between the tooth boots of the motor rotor assembly and the stator assembly 100. At the position corresponding to the groove 14, the maximum radial width of the stator-rotor air gap is δmax and the minimum radial width is δmin, 1.0mm≤δmax≤1.5mm, 0.4mm≤δmin≤0.8mm. The rotor core 1 has a trimming structure (i.e., the aforementioned groove 14) and a slotting structure (i.e., the open slot 15 hereinbelow) and other designs to form an uneven air gap, and the air gap magnetic field is close to a sinusoidal waveform, thereby reducing eddy current loss and magnet temperature rise, reducing the risk of demagnetization of the permanent magnet, and improving the magnetomotive force and magnetic concentration capacity. It is configured to have multiple recesses near the end of the permanent magnet and close to the outer circumference of the rotor. By adjusting the trimming size, the air gap magnetic density generated is close to a sine curve, and the width between the end size of the permanent magnet in the rotor slot and the recess is reduced, which plays a role in separating the permanent magnets. At the same time, due to the increase in the air gap, the radial electromagnetic force is reduced and the electromagnetic noise is lowered. That is, in this technical solution, the slotted structure of the rotor outer circle utilizes the uneven air gap to improve the voltage waveform induced in the stator winding, thereby achieving efficient and stable operation of the compression system.

[0052] In some embodiments, a plurality of open slots 15 are provided in the corresponding area between two adjacent second magnetic steel slots 12 of the rotor core 1. The open slots 15 extend through the axial ends of the rotor core 1 along the axial direction. The open slots 15 are connected to the outer circumferential side of the rotor core 1 through the openings they have. The opening design of the open slots 15 can effectively reduce the skin effect on the outer circumferential wall of the rotor core 1. The open slots 15 can specifically be parallel slots. Preferably, in some embodiments, a magnetic isolation bar 31 passes through the open slots 15. The two ends of the magnetic isolation bar 31 are respectively connected to magnetic isolation end rings 32, that is, the magnetic isolation end rings 32 at both ends and the magnetic isolation bar 31 in the middle form a squirrel cage structure. The skin effect of the motor rotor assembly configured in this way is more significant than that of the parallel tooth slot shape (that is, the aforementioned open slots 15), which can reduce current, adjust speed and torque, and is beneficial to improving starting performance. By adjusting the structural dimensions of the squirrel cage bars and end rings, the dynamic and steady-state performance of the motor can be improved. The magnetic isolation bars 31 and magnetic isolation end rings 32 are made of poor magnetic conductors such as aluminum, copper, or alloys of the two, giving the squirrel cage structure a magnetic isolation effect. Since the magnetic permeability of aluminum or copper is similar to that of air, it also protects the permanent magnets from demagnetization. Each squirrel cage bar slot is disconnected at the outer magnetic isolation bridge at the outer end of the outer circle, which can ensure the strength of the rotor structure while reducing magnetic leakage from the outer magnetic isolation bridge and improving the utilization rate of the permanent magnets. The rotor assembly designed in this way allows the permanent magnet magnetic flux to enter and exit radially, and the magnetic flux generated by the stator winding current does not meander along the rotor circumference, reducing motor noise and vibration and improving motor efficiency.

[0053] It should be noted that the starting winding (squirrel cage conductor bar) end ring structure is provided on the rotor of the general permanent magnet synchronous motor, which has the ability to start by itself, eliminating the starting device, saving costs, and achieving high efficiency and energy saving. The starting winding (squirrel cage conductor bar) end ring structure is provided in the speed-regulating permanent magnet synchronous motor to adjust the starting torque and speed of the motor, which can improve the dynamic performance of the motor and achieve motor self-starting (the principle is the same as that of the asynchronous motor). The existing compressor motor rotor punching sheet is changed from the common buckle point forming method to the punching sheet without buckle point or with less buckle point structure. The punching sheet and the rotor end ring (squirrel cage end ring) are assembled into an integral iron core through tooling positioning during the die-casting production process, thereby reducing iron loss and improving motor efficiency.

[0054] In some embodiments, a notch groove 321 corresponding to the position of the second magnetic steel slot 12 is provided on the inner circle of the magnetic isolation end ring 32, the circumferential width of the notch groove 321 is w4, the circumferential width of the second magnetic steel 22 is w22, and the radial length is h22, w4>w22, and the distance between the radial groove bottom wall of the notch groove 321 and the radial inner groove wall of the second magnetic steel slot 12 is not less than h22. In this way, the aforementioned squirrel cage structure and the rotor core 1 can be cast as one piece first, and then the second magnetic steel 22 can be inserted into the second magnetic steel slot 12 through the notch groove 321 to prevent the magnetic steel from being demagnetized at high temperature during the casting process of the squirrel cage structure.

[0055] In some embodiments, the axial end of the rotor core 1 is also connected to a balancing block 4, which is embedded in the inner circle of the magnetic isolation end ring 32. It forms a reliable connection with the stacked rotor core 1 through rivets. The balancing block 4 can achieve dynamic balance of the rotating shaft while also effectively sealing the axial ends of the first magnetic steel 21 and the second magnetic steel 22.

[0056] The number of magnetic poles of the motor rotor assembly is N, and the number of magnetic steel slots is 2N. N can be a positive integer such as 6, 8, 10, or 12. Figure 1 8 poles shown.

[0057] The present invention realizes the self-starting function of the motor by arranging a squirrel cage structure on the outer circle of the rotor; by improving the rotor structure, the permanent magnet leakage is reduced, the permanent magnet utilization rate is increased, the structural strength of the rotor during operation and the motor efficiency are improved, which can reduce torque pulsation, improve harmonic components, and reduce losses, vibration and noise; the combination of tangential magnetic steel enhances electromagnetic torque, reduces production costs and improves motor efficiency.

[0058] According to an embodiment of the present invention, there is further provided a motor, in particular a motor with a tangential structure having a built-in permanent magnet, comprising the above-mentioned motor rotor assembly.

[0059] According to an embodiment of the present invention, a compressor is further provided, comprising the above-mentioned motor rotor assembly.

[0060] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A motor rotor assembly, characterized in that: The invention comprises a rotor core (1), wherein the rotor core (1) is constructed with two or more first magnetic steel slots (11) passing through the two axial ends thereof, wherein the first magnetic steel slots (11) are provided with first magnetic steels (21), and the slot inner walls at the two axial ends of the first magnetic steel slots (11) are provided with first protrusions (111), wherein the first protrusions (111) extend from the inside to the outside along the radial direction of the rotor core (1) so as to be supported at the axial two end positions of the radial inner side surface of the first magnetic steel (21), and a gap is formed between the middle position of the first magnetic steel (21) and the slot wall of the first magnetic steel slot (11); and the rotor core (1) is further constructed with a plurality of second magnetic steel slots (12) passing through the two axial ends thereof, wherein the second magnetic steel slots (12) are provided with second magnetic steels (21). The rotor core (1) comprises a plurality of grooves (14) on its outer circumferential wall, each groove (14) being symmetrical about the q axis, and having a groove depth that decreases from the middle to both sides, and a fourth magnetic isolation bridge is formed between the groove bottom wall of the groove (14) and the radial outer groove wall of the second magnetic steel groove (12), and the minimum radial thickness of the fourth magnetic isolation bridge is h5, 0.2mm≤h5; a plurality of open grooves (15) are provided on the corresponding area between two adjacent second magnetic steel grooves (12) of the rotor core (1), and the open grooves (15) pass through the axial ends of the rotor core (1) along the axial direction, and the open grooves (15) are connected to the outer circumferential side of the rotor core (1) through the openings they have.

2. The motor rotor assembly according to claim 1, characterized in that: The axial projection of the first protrusion (111) on the radial surface of the rotor core (1) is a semicircle; and / or the axial length of the first protrusion (111) in the rotor core (1) is L1, the axial length of the rotor core (1) is L, and 1 / 100≤L1 / L≤1 / 20.

3. The motor rotor assembly according to claim 1, characterized in that: The second magnetic steel slot (12) is located radially outside the first magnetic steel slot (11) and is symmetrical about the same q axis.

4. The motor rotor assembly according to claim 3, characterized in that: The second magnetic steel slot (12) has second protrusions (121) on the inner walls of the slot at both axial ends. The second protrusions (121) extend from the inside to the outside in the radial direction of the rotor core (1) so as to be supported at both axial ends of the radial inner side surface of the second magnetic steel (22).

5. The motor rotor assembly according to claim 4, characterized in that: The rotor core (1) comprises an intermediate core segment and end core segments stacked on both axial ends of the intermediate core segment, the end core segments being formed by stacking a plurality of first punching sheets (101), the first protrusions (111) and the second protrusions (121) being both constructed at corresponding positions of the first punching sheets (101), the intermediate core segment being formed by stacking a plurality of second punching sheets (102), the second punching sheets (102) not having the first protrusions (111) and the second protrusions (121).

6. The motor rotor assembly according to claim 5, characterized in that: The radial length of the first magnetic steel (21) is h11, the circumferential width is w11, the minimum radial spacing of the first magnetic steel slot (11) is h1, the circumferential spacing is w1, h1>h11, w1>w11; and / or the radial length of the second magnetic steel (22) is h22, the circumferential width is w22, the minimum radial spacing of the second magnetic steel slot (12) is h2, the circumferential spacing is w2, h2>h22, w2>w22.

7. The motor rotor assembly according to claim 6, characterized in that: w11>w22 and h11>h22, the first magnetic steel (21) is a ferrite permanent magnet, and the second magnetic steel is a rare earth permanent magnet.

8. The motor rotor assembly according to claim 6, characterized in that: The radius of the semicircular first protrusion (111) is R1, 1 / 50≤R1 / h1≤1 / 10; and / or the first magnetic steel slot (11) is symmetrical about the corresponding q axis, and the first protrusion (111) is symmetrical about the q axis.

9. The motor rotor assembly according to claim 6, characterized in that: The axial projection of the second protrusion (121) on the radial surface of the rotor core (1) is semicircular; and / or, the length of the second protrusion (121) in the axial direction of the rotor core (1) is d2, L1=d2, and the length of the first protrusion (111) in the axial direction of the rotor core (1) is L1; and / or, the radius of the semicircular second protrusion (121) is R2, 1 / 50≤R2 / h2≤1 / 10; and / or, the second magnetic steel slot (12) is symmetrical about the q axis, and the second protrusion (121) is symmetrical about the q axis.

10. The motor rotor assembly according to claim 4, characterized in that: A first magnetic isolation bridge is formed between the radial outer slot wall of the first magnetic steel slot (11) and the radial inner slot wall of the second magnetic steel slot (12), and the minimum radial thickness of the first magnetic isolation bridge is h4, 0.2mm≤h4; and / or, a second magnetic isolation bridge is formed between the radial inner slot walls of two adjacent first magnetic steel slots (11) in the circumferential direction of the rotor core (1), and the minimum circumferential width of the second magnetic isolation bridge is h6, 0.2mm≤h6; and / or, a flow hole (13) is provided on the radial inner side of the first magnetic steel slot (11), and the flow hole (13) is symmetrical about the q axis, and a third magnetic isolation bridge is formed between the radial inner slot wall of the first magnetic steel slot (11) and the radial outer slot wall of the flow hole, and the minimum radial thickness of the third magnetic isolation bridge is h3, 0.2mm≤h3.

11. The motor rotor assembly according to claim 1, characterized in that: When the motor rotor assembly is assembled with the stator assembly (100) corresponding thereto, a stator-rotor air gap is formed between the tooth boots of the motor rotor assembly and the stator assembly (100), and at a position corresponding to the groove (14), the stator-rotor air gap has a maximum radial width of δmax and a minimum radial width of δmin, and the range is 1.0 mm ≤ δmax ≤ 1.5 mm, and 0.4 mm ≤ δmin ≤ 0.8 mm.

12. The motor rotor assembly according to claim 1, characterized in that: A magnetic isolation guide bar (31) passes through the open slot (15), and both ends of the magnetic isolation guide bar (31) are respectively connected to magnetic isolation end rings (32).

13. The motor rotor assembly according to claim 12, characterized in that: The inner circle of the magnetic isolation end ring (32) has a notch groove (321) corresponding to the position of the second magnetic steel groove (12), the circumferential width of the notch groove (321) is w4, the circumferential width of the second magnetic steel (22) is w22, and the radial length is h22, w4>w22, and the distance between the radial groove bottom wall of the notch groove (321) and the radial inner groove wall of the second magnetic steel groove (12) is not less than h22.

14. The motor rotor assembly according to claim 12, wherein: The shaft end of the rotor core (1) is further connected to a balancing block (4), and the balancing block (4) is embedded in the inner circle of the magnetic isolation end ring (32).

15. A motor, characterized in that: A motor rotor assembly comprising the motor rotor assembly according to any one of claims 1 to 14.

16. A compressor, characterized in that: A motor rotor assembly comprising any one of claims 1 to 15.

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