Rotor assembly, permanent magnet synchronous motor and compressor

Abstract

The present application provides a rotor assembly, a permanent magnet synchronous motor, and a compressor. The rotor assembly includes a rotor punching, which is provided with a magnetic steel slot and a magnetic isolation hole; the rotor punching is provided with a first slot, the first slot is provided on the outer periphery, and is located between the adjacent magnetic isolation hole and the bending slot; or / and, the rotor punching is provided with a second slot, the second slot is provided on the side of the strip slot, and is located between the adjacent magnetic isolation hole and the bending slot. The present application slots the outer periphery of the rotor punching or / and slots the side of the magnetic steel slot, which can dredge the magnetic circuit, improve the uniformity of the motor air gap magnetic resistance, and achieve the purpose of reducing the harmonic content of the motor, thereby reducing motor losses and improving efficiency.

Description

Technical Field

[0001] The present application belongs to the technical field of compressors, and specifically relates to a rotor assembly, a permanent magnet synchronous motor and a compressor. Background Art

[0002] Currently, the energy efficiency level in the home appliance industry has approached the upper limit, so the noise problem of the products has become prominent.

[0003] The torque pulsation of the motor in the compressor has a great influence on the vibration of the motor, so the industry generally pays attention to the structure that affects this parameter. For example, the method of opening magnetic isolation holes in the main magnetic circuit of the rotor is commonly used to reduce torque pulsation.

[0004] However, after using conventional methods to add magnetic isolation holes to optimize pulsation and harmonics, or when the torque pulsation and harmonics of the motor itself have been reduced to the limit level without adding magnetic isolation holes, optimizing the position of the magnetic isolation holes and increasing the number of magnetic isolation holes will not reduce the torque pulsation, and may even reduce the motor efficiency. Summary of the Invention

[0005] Therefore, the present application provides a rotor assembly, a permanent magnet synchronous motor and a compressor, which can solve the problem in the prior art that the torque pulsation will not decrease and may even reduce the efficiency of the motor.

[0006] In order to solve the above problems, the present application provides a rotor assembly, comprising:

[0007] The rotor punching is equipped with magnetic steel slots and magnetic isolation holes;

[0008] The magnetic steel slot includes a strip slot and a bent slot, wherein two bent slots are provided, respectively connected to the two ends of the strip slot and extending toward the outer periphery of the rotor punching;

[0009] Two magnetic isolation holes are provided in the area formed by each magnetic steel slot and the outer periphery of the corresponding rotor punching sheet, and each magnetic isolation hole is close to one of the bending slots;

[0010] The rotor punching is provided with a first slot, the first slot is provided on the outer periphery and is located between the adjacent magnetic isolation holes and the bending slots; or / and,

[0011] The rotor punching sheet is provided with a second slot, which is provided on a side of the strip-shaped slot and located between the adjacent magnetic isolation holes and the bending slot.

[0012] Optionally, the first slot is formed by connecting a straight slot edge and an arc-shaped slot bottom, and a center line of the first slot does not pass through the center of the rotor punching.

[0013] Optionally, the center of the circle of the slot bottom and the q-axis of the rotor punching closest to it are located on one side of the first slot centerline and on the other side of the first slot centerline.

[0014] Optionally, the angle between the first slot centerline and the q-axis is set to α1, satisfying 15°≤α1≤21°.

[0015] Optionally, the shortest distance between the line connecting the groove edge and the groove bottom connection point and the center of the groove bottom is set to L2, satisfying 0.059mm≤L2≤0.08mm.

[0016] Optionally, the radius of the arc at the bottom of the groove is set to R1, satisfying 0.61mm≤R1≤0.77mm.

[0017] Optionally, a minimum distance between the second slot and one end of the strip-shaped slot is set to L1, satisfying L1≤0.15 mm.

[0018] Optionally, the second slot is set to be semicircular, and the center of the circle is located on the side of the strip slot; the radius of the second slot is set to R2, satisfying R2+L1≤1.68mm.

[0019] Optionally, a radius R2 of the second slot satisfies 1.39 mm ≤ R2.

[0020] Optionally, a center line of the second slot intersects a center line of the first slot, and an included angle is set to α2, satisfying 14°≤α2≤16°.

[0021] Optionally, the minimum distance between the center of the bottom of the first slot and the q-axis of the rotor punching is set to L3, and the minimum distance between the center of the second slot and the q-axis of the rotor punching is set to L4, satisfying 0≤L3-L4≤2.2mm.

[0022] According to another aspect of the present application, a permanent magnet synchronous motor is provided, comprising the rotor assembly as described above.

[0023] According to yet another aspect of the present application, a compressor is provided, comprising the rotor assembly as described above or the permanent magnet synchronous motor as described above.

[0024] A rotor assembly provided in the present application includes: a rotor punching, which is provided with a magnetic steel slot and a magnetic isolation hole; the magnetic steel slot includes a strip slot and a bent slot, and two bent slots are provided, which are respectively connected to the two ends of the strip slot and extend toward the outer periphery of the rotor punching; two magnetic isolation holes are provided in the area formed by each magnetic steel slot and the corresponding outer periphery of the rotor punching, and each magnetic isolation hole is close to one of the bent slots; a first slot is provided on the rotor punching, the first slot is provided on the outer periphery, and is located between adjacent magnetic isolation holes and the bent slots; or / and, a second slot is provided on the rotor punching, the second slot is provided on the side of the strip slot, and is located between adjacent magnetic isolation holes and the bent slots.

[0025] The present application makes slots on the outer periphery of the rotor punching sheets and / or on the side edges of the magnetic steel slots, which can dredge the magnetic circuit, improve the uniformity of the motor air gap magnetic resistance, and achieve the purpose of reducing the harmonic content of the motor, thereby reducing motor losses and improving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of a rotor assembly according to an embodiment of the present application;

[0027] Figure 2 This is a schematic structural diagram of the first slot in an embodiment of the present application;

[0028] Figure 3 A diagram showing the relationship between the first slot and the q-axis in an embodiment of the present application;

[0029] Figure 4 This is an enlarged structural diagram of the first slot in an embodiment of the present application;

[0030] Figure 5 This is a structural diagram of the first slot in an embodiment of the present application;

[0031] Figure 6 This is a schematic structural diagram of the second slot in an embodiment of the present application;

[0032] Figure 7 A diagram showing the relationship between the first slot and the second slot in an embodiment of the present application;

[0033] Figure 8 This is a comparison chart of the air gap harmonic content of the permanent magnet synchronous motor of the embodiment of the present application and the air gap harmonic content of the traditional structure;

[0034] Figure 9 This is a comparison chart of the rated point efficiency of the permanent magnet synchronous motor according to the embodiment of the present application and the rated point efficiency of the conventional structure;

[0035] Figure 10 This is a comparison diagram of the optimal air gap harmonic content and the non-optimal air gap harmonic content of the permanent magnet synchronous motor according to the embodiment of the present application;

[0036] Figure 11 A comparison chart of the non-optimal air gap harmonic content and the air gap harmonic content outside this value range of the permanent magnet synchronous motor according to an embodiment of the present application;

[0037] The reference numerals indicate:

[0038] 1. Rotor punching sheet; 11. Q-axis; 2. Magnetic steel slot; 21. Strip slot; 22. Bend slot; 3. Magnetic isolation hole; 4. First slot; 41. Slot edge; 42. Slot bottom; 421. Slot bottom center; 43. Centerline of first slot; 5. Second slot. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] See also Figures 1 to 11 As shown, according to an embodiment of the present application, a rotor assembly includes:

[0042] The rotor punching 1 is provided with a magnetic steel slot 2 and a magnetic isolation hole 3;

[0043] The magnetic steel slot 2 includes a strip slot 21 and a bent slot 22. Two bent slots 22 are provided, respectively connected to the two ends of the strip slot 21 and extending toward the outer periphery of the rotor punching 1.

[0044] Two magnetic isolation holes 3 are provided on the area formed by each magnetic steel slot 2 and the outer periphery of the corresponding rotor punching 1, and each magnetic isolation hole 3 is close to one of the bending slots 22;

[0045] The rotor punching 1 is provided with a first slot 4, which is provided on the outer periphery and located between the adjacent magnetic isolation holes 3 and the bending slot 22; or / and,

[0046] The rotor punching 1 is provided with a second slot 5 , which is provided on a side of the strip slot 21 and between the adjacent magnetic isolation holes 3 and the bending slot 22 .

[0047] This application adopts the method of providing a first slot 4 on the outer periphery of the rotor punching 1, and the first slot 4 is not provided on the q-axis 11. Since the rotor edge is generally fragile at the q-axis 11, adding a slot will lead to poor mechanical properties of the rotor, which may cause damage during high-speed operation. A second slot 5 can also be provided on the side of the magnetic steel slot 2. This can dredge the magnetic circuit, improve the uniformity of the motor air gap magnetic resistance, and achieve the purpose of reducing the harmonic content of the motor, thereby reducing motor losses and improving efficiency.

[0048] The second slot 5 is a hole in the magnet slot 2. During operation, a medium flows through it, which cools the magnet. Most synchronous motors currently use rare earth magnets, with neodymium iron boron being the main one. This material becomes unstable at high temperatures, and its performance and anti-demagnetization ability both decrease. Therefore, lowering the temperature of the magnet will also improve the overall efficiency and reliability of the rare earth permanent magnet synchronous motor.

[0049] The magnetic lines of force start from the magnet. When not saturated, the second slot 5 diverts the magnetic lines of force to both sides and then reaches the first slot 4. The harmonics are caused by the uneven air gap magnetic resistance. The first slot 4 also diverts the magnetic circuit and changes the air gap magnetic resistance. After simulation, it was found that the best effect is achieved when both slots exist at the same time, and the torque output does not decrease.

[0050] It's best to have both slots at the same time. To achieve optimal results, the size and shape must meet the requirements; otherwise, the motor torque ripple will be larger than with the optimal size. The two slots can be set at different times, but the effect is essentially the same if they are set separately.

[0051] In some embodiments, the first slot 4 is formed by connecting a straight slot edge 41 and an arc-shaped slot bottom 42, and the centerline of the first slot 4 does not pass through the center of the rotor punching 1. Preferably, the center of the slot bottom 42 and the q-axis 11 of the rotor punching 1 closest to it are located on one side of the first slot centerline 43 and on the other side of the first slot centerline 43.

[0052] In the first slot 4 , the slot edge 41 may be connected to the slot bottom 42 in a straight line, or the slot edge 41 may be connected to the slot bottom 42 in a straight line. However, the tangential connection method may reduce the harmonic content.

[0053] Preferably, the angle α1 between the first slot centerline 43 and the q-axis 11 satisfies 15° ≤ α1 ≤ 21°; more preferably, α1 = 16°. Preferably, the shortest distance between the line connecting the groove edge 41 and the groove bottom 42 and the center of the groove bottom 42 is L2, which satisfies 0.059 mm ≤ L2 ≤ 0.08 mm; more preferably, L2 = 0.06. Preferably, the radius of the arc of the groove bottom 42 is R1, which satisfies 0.61 mm ≤ R1 ≤ 0.77 mm; more preferably, R1 = 0.615 mm.

[0054] In some embodiments, the minimum distance between the second slot 5 and one end of the strip groove 21 is set to L1, satisfying L1 ≤ 0.15 mm. Preferably, the second slot 5 is semicircular, with its center located on the side of the strip groove 21. The radius of the second slot 5 is set to R2, satisfying R2 + L1 ≤ 1.68 mm; more preferably, R2 + L1 = 1.55 mm. Preferably, the radius R2 of the second slot 5 satisfies 1.39 mm ≤ R2; more preferably, R2 = 1.42 mm.

[0055] In some embodiments, the center line of the second slot 5 intersects the center line of the first slot 4, and the included angle is set to α2, satisfying 14°≤α2≤16°; more preferably, α2=14°.

[0056] In some embodiments, the minimum distance between the center 421 of the bottom of the first slot 4 and the q-axis 11 of the rotor punching 1 is set to L3, and the minimum distance between the center of the second slot 5 and the q-axis 11 of the rotor punching 1 is set to L4, satisfying 0≤L3-L4≤2.2mm; more preferably, L3-L4=1.95mm.

[0057] According to another aspect of the present application, a permanent magnet synchronous motor is provided, comprising the rotor assembly as described above.

[0058] The following is an analysis and comparison of the motor with the traditional structure under the condition of using two slots at the same time and taking the most preferred value for the above values. The results are as follows Figure 8 and 9 As shown, the harmonic content of the motor of the present application is greatly reduced, while the rated point efficiency is improved.

[0059] In addition, the case where two slots are used at the same time and the most preferred value is used for the above value is analyzed and compared with the case where the value is not preferred. The results are as follows: Figure 10 As shown in the figure, the optimization effects have decreased to varying degrees.

[0060] The above-mentioned most preferred values ​​are: L1=0.1mm, R2=1.45mm, α1=15°, R1=0.7mm, L2=0.07mm, α2=16°, L3-L4=2mm.

[0061] However, if the above values ​​are outside the range specified in this application, for example, L1 = 0.2mm, R2 = 1.6mm, α1 = 14°, R1 = 0.5mm, L2 = 0.09mm, α2 = 13°, and L3-L4 = 2.3mm, the comparison chart shows that the main harmonic contents of the 5th, 7th, 11th, and 13th harmonics in the air gap of the motor using the structure of this application are significantly reduced.

[0062] According to yet another aspect of the present application, a compressor is provided, comprising the rotor assembly as described above or the permanent magnet synchronous motor as described above.

[0063] It is easy for those skilled in the art to understand that the above embodiments can be freely combined and superimposed without conflict.

[0064] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application. The above description is merely a preferred embodiment of the present application. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present application, and such improvements and variations shall also be considered within the scope of protection of the present application.

Claims

1. A rotor assembly, characterized in that: include: A rotor punching sheet (1) is provided with a magnetic steel slot (2) and a magnetic isolation hole (3); The magnetic steel slot (2) includes a strip slot (21) and a bent slot (22), wherein two bent slots (22) are provided, respectively connected to the two ends of the strip slot (21) and extending toward the outer periphery of the rotor punching (1); Two magnetic isolation holes (3) are provided on the area formed by each magnetic steel slot (2) and the outer periphery of the corresponding rotor punching sheet (1), and each magnetic isolation hole (3) is close to one of the bending slots (22); The rotor punching sheet (1) is provided with a first slot (4), the first slot (4) being provided on the outer periphery and being located between the adjacent magnetic isolation holes (3) and the bending slot (22); or / and, The rotor punching sheet (1) is provided with a second slot (5), the second slot (5) being provided on a side of the strip slot (21) and being located between the adjacent magnetic isolation holes (3) and the bending slot (22); The first slot (4) is formed by connecting a straight slot edge (41) and an arc-shaped slot bottom (42), and the center line of the first slot (4) does not pass through the center of the rotor punching (1); The center of the groove bottom (42) and the q axis (11) of the rotor punching (1) closest to it are located on one side of the center line of the first slot (4) and on the other side of the center line of the first slot (4).

2. The rotor assembly according to claim 1, wherein: The angle between the center line of the first slot (4) and the q-axis (11) is set to α1, satisfying 15°≤α1≤21°.

3. The rotor assembly according to claim 1, wherein: The shortest distance between the connecting line between the groove edge (41) and the groove bottom (42) and the center of the circle of the groove bottom (42) is set to L2, which satisfies 0.059mm≤L2≤0.08mm.

4. The rotor assembly according to claim 3, wherein: The radius of the arc of the groove bottom (42) is set to R1, which satisfies 0.61mm≤R1≤0.77mm.

5. The rotor assembly according to any one of claims 1 to 4, characterized in that: The minimum distance between the second slot (5) and one end of the strip slot (21) is set to L1, satisfying L1≤0.15mm.

6. The rotor assembly according to claim 5, characterized in that The second slot (5) is set to be semicircular, with the center of the circle located on the side of the strip slot (21); the radius of the second slot (5) is set to R2, satisfying R2+L1≤1.68mm.

7. The rotor assembly according to claim 6, wherein: The radius R2 of the second slot (5) satisfies 1.39 mm ≤ R2.

8. The rotor assembly according to claim 5, wherein: The center line of the second slot (5) intersects with the center line of the first slot (4), and the included angle is set to α2, satisfying 14°≤α2≤16°.

9. The rotor assembly according to claim 8, wherein: The minimum distance between the center of the bottom of the first slot (4) and the q axis (11) of the rotor punch (1) is set to L3, and the minimum distance between the center of the second slot (5) and the q axis (11) of the rotor punch (1) is set to L4, satisfying 0≤L3-L4≤2.2mm.

10. A permanent magnet synchronous motor, characterized in that: The invention comprises a rotor assembly according to any one of claims 1 to 9.

11. A compressor, characterized in that: It comprises the rotor assembly according to any one of claims 1 to 9 or the permanent magnet synchronous motor according to claim 10.

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