Rotors, motors and compressors

Abstract

This invention relates to a rotor, a motor, and a compressor, specifically to the field of drive equipment technology, and is used to reduce the proportion of harmonics caused by air gap magnetic flux density, thereby reducing motor torque pulsation and vibration noise. The rotor of this invention includes a rotor core with magnetic slots and a shaft hole located in the middle of the rotor core. A magnetic isolation bridge is formed between the end of the magnetic slot and the outer surface of the rotor core. The magnetic isolation bridge includes at least two magnetic isolation sections, the thickness of which gradually decreases along the direction away from the shaft hole. The advantage of this invention is that by using magnetic isolation sections of varying thicknesses, the magnetic permeability of the rotor magnetic poles is more uniform in the circumferential and radial directions, changing the magnetic reluctance distribution throughout the motor's magnetic circuit, thereby reducing the cogging effect of the motor, improving the magnetic flux direction, and effectively reducing motor torque pulsation, peak electromagnetic force, and electromagnetic vibration noise.

Description

Technical Field

[0001] This invention relates to the field of drive equipment technology, and particularly to a rotor, motor and compressor. Background Technology

[0002] Permanent magnet motors generate the main magnetic field using permanent magnets. They have high air gap magnetic flux density, high efficiency, small size, high power density, simple structure, and high reliability, and are widely used in various industries.

[0003] Traditionally, rare earth neodymium iron boron permanent magnet synchronous motors are widely used. Rare earth is an important national strategic reserve material. The production of rare earth permanent magnet materials is affected by the control of upstream raw materials, which suppresses production. Ferrite, on the other hand, has gained greater development space due to its high cost-performance advantage. Permanent magnet assisted reluctance motors are widely used and researched due to their reluctance torque advantage.

[0004] However, in traditional permanent magnet assisted reluctance motors, the permanent magnet material, with its fixed grade and material, has a constant magnetic energy product, such as... Figure 7 As shown, the air gap magnetic field of the motor is difficult to adjust. At the same time, the tooth and cogging structure of the motor results in a large harmonic content of air gap magnetic flux density and back electromotive force, and a large peak electromagnetic force of the motor, which leads to large torque pulsation and vibration noise. Summary of the Invention

[0005] The present invention provides a rotor, a motor and a compressor for reducing the proportion of harmonics caused by air gap magnetic flux density in order to reduce motor torque pulsation and vibration noise.

[0006] The present invention provides a rotor including a rotor core, wherein the rotor core is provided with a magnetic steel groove and a shaft hole located in the middle of the rotor core, and a magnetic isolation bridge is formed between the end of the magnetic steel groove and the outer surface of the rotor core, the magnetic isolation bridge including at least two magnetic isolation parts, and the at least two magnetic isolation parts having different thicknesses.

[0007] The magnetic isolation bridge includes a first magnetic isolation part and a second magnetic isolation part. The first magnetic isolation part and the second magnetic isolation part are arranged along the width direction of the magnetic steel groove, and the first magnetic isolation part is located on the side of the second magnetic isolation part away from the rotating shaft hole. The thickness of the first magnetic isolation part is less than the thickness of the second magnetic isolation part.

[0008] The ratio of the thickness of the first magnetic shielding part to the thickness of the second magnetic shielding part ranges from 0.5 to 0.9.

[0009] The relationship between the width C of the first magnetic shielding part and the width D of the second magnetic shielding part is 1≤C / D≤1.5.

[0010] The magnetic steel groove includes an outer magnetic steel groove and an inner magnetic steel groove. The inner magnetic steel groove is located between the outer magnetic steel groove and the shaft hole. One of the magnetic isolation bridges is formed between the end of the outer magnetic steel groove and the outer surface of the rotor core, and the other magnetic isolation bridge is formed between the end of the inner magnetic steel groove and the outer surface of the rotor core.

[0011] An external magnetic bridge is formed between the end of the outer magnetic steel slot and the outer surface of the rotor core. The external magnetic bridge includes a first external magnetic shielding part and a second external magnetic shielding part. The thickness of the first external magnetic shielding part is less than that of the second external magnetic shielding part. An internal magnetic bridge is formed between the end of the inner magnetic steel slot and the outer surface of the rotor core. The internal magnetic bridge includes a first internal magnetic shielding part and a second internal magnetic shielding part. The thickness of the first internal magnetic shielding part is less than that of the second internal magnetic shielding part. The ratio of the thickness G of the first external magnetic shielding part to the thickness A of the first internal magnetic shielding part is in the range of 0.5 ≤ G / A ≤ 0.9; and / or, the ratio of the thickness H of the second external magnetic shielding part to the thickness B of the second internal magnetic shielding part is in the range of 0.6 ≤ H / B ≤ 0.8.

[0012] The rotor core is provided with a deepening groove, which is located between the end of the magnet slot and the outer surface of the rotor core, and the deepening groove is connected to the magnet slot. The first magnetic isolation part is formed between the deepening groove and the outer surface of the rotor core.

[0013] The opening of the deepening groove is connected to the end of the magnet groove, and the width of the opening of the deepening groove is smaller than the width of the end of the magnet groove.

[0014] The width of the deepening groove gradually increases from the opening to the bottom of the deepening groove.

[0015] The ratio of the width E of the opening of the deepening groove to the width F of the bottom of the deepening groove is in the range of 1.1 ≤ F / E ≤ 1.4.

[0016] The cross-section of the magnetic steel groove is arc-shaped.

[0017] An electric motor, comprising the rotor described above.

[0018] A compressor comprising the rotor described above or the motor described above.

[0019] Compared with the prior art, the advantages of the present invention are that by using magnetic shielding parts of different thicknesses, the magnetic permeability of the rotor magnetic poles in the circumferential and radial directions is more uniform, the magnetic resistance distribution in the motor magnetic circuit is changed, thereby reducing the cogging effect of the motor, improving the magnetic flux direction, and effectively reducing the motor torque pulsation, electromagnetic force peak and electromagnetic vibration noise. Attached Figure Description

[0020] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0021] Figure 1 This is a schematic diagram of the rotor structure in an embodiment of the present invention;

[0022] Figure 2 This is another schematic diagram of the rotor structure in an embodiment of the present invention;

[0023] Figure 3 This is another schematic diagram of the rotor structure in an embodiment of the present invention;

[0024] Figure 4 This is a comparison diagram of torque ripple between the motor of an embodiment of the present invention and a motor in the prior art;

[0025] Figure 5 This is a comparison diagram of the peak electromagnetic force density of a motor according to an embodiment of the present invention and a motor in the prior art;

[0026] Figure 6 This is a comparison chart of the total compressor noise values ​​of the motor in an embodiment of the present invention and the motor in the prior art;

[0027] Figure 7 This is a schematic diagram of the rotor structure in the prior art;

[0028] Figure label:

[0029] 1. Rotor core; 2. Magnet slot; 21. Outer magnet slot; 22. Inner magnet slot; 3. Shaft hole; 4. Magnetic isolation bridge; 41. First magnetic isolation part; 42. Second magnetic isolation part; 43. Outer magnetic isolation bridge; 431. First outer magnetic isolation part; 432. Second outer magnetic isolation part; 44. Inner magnetic isolation bridge; 441. First inner magnetic isolation part; 442. Second inner magnetic isolation part; 5. Deepened slot. Detailed Implementation

[0030] The invention will now be further described with reference to the accompanying drawings.

[0031] like Figures 1 to 6 As shown, the present invention provides a rotor, including a rotor core 1. The rotor core 1 has magnetic slots 2 and a shaft hole 3 located in the middle of the rotor core 1. A magnetic isolation bridge 4 is formed between the end of the magnetic slot 2 and the outer surface of the rotor core 1. The magnetic isolation bridge 4 includes at least two magnetic isolation sections with different thicknesses. By using magnetic isolation sections of different thicknesses, the magnetic permeability of the rotor magnetic poles in the circumferential and radial directions is made more uniform, changing the magnetic reluctance distribution in the motor's magnetic circuit, thereby reducing the cogging effect of the motor, improving the magnetic flux direction, and effectively reducing the motor's torque pulsation, electromagnetic force peak value, and electromagnetic vibration noise.

[0032] The magnetic slot 2 is equipped with permanent magnets. The same magnetic pole of the rotor contains N layers of permanent magnets, N≥2. The permanent magnets in the same magnetic pole have the same polarity in the stator direction facing the outside of the rotor.

[0033] The center of the magnet slot 2 is close to the shaft hole 3, and the end of the magnet slot 2 is close to the outer surface of the rotor. Preferably, the cross-section of the magnet slot 2 is arc-shaped, and the direction of the arc protrusion is towards the axis of the shaft hole 3.

[0034] Specifically, the magnetic isolation bridge 4 includes a first magnetic isolation part 41 and a second magnetic isolation part 42. The first magnetic isolation part 41 and the second magnetic isolation part 42 are arranged along the width direction of the magnetic steel groove 2, and the first magnetic isolation part 41 is located on the side of the second magnetic isolation part 42 away from the shaft hole 3. The thickness of the first magnetic isolation part 41 is less than the thickness of the second magnetic isolation part 42. The first magnetic isolation part 41 has a small thickness and a large magnetic resistance, while the second magnetic isolation part 42 has a large thickness and a small magnetic resistance. By setting the first magnetic isolation part 41 outside the second magnetic isolation part 42, the magnetic resistance distribution of the air gap at various points on the outer surface of the rotor can be effectively improved, thereby improving the air gap magnetic field distribution and magnetic flux direction, and thus effectively reducing the torque pulsation, electromagnetic force peak value, and electromagnetic vibration noise of the motor.

[0035] like Figure 4 As shown, the motor of an embodiment of the present invention has the rotor described above, which differs from that in the prior art. Figure 7 Compared to the rotor shown in the motor, the motor torque ripple of the embodiment of the present invention is 15%, thus reducing the motor torque ripple of the embodiment of the present invention by more than 50% compared to the prior art.

[0036] like Figure 5 As shown, the motor of an embodiment of the present invention has the rotor described above, which differs from that in the prior art. Figure 7 Compared to the rotor motor shown, the maximum peak value of the electromagnetic force density in the embodiment of the present invention is 2900, thus the peak value of the electromagnetic force density in the embodiment of the present invention is increased by more than 45% compared to the prior art.

[0037] like Figure 6 As shown, the compressor of an embodiment of the present invention has the above-described rotor, which differs from those in the prior art. Figure 7 Compared to the rotor compressor described above, the compressor noise level of the embodiment of the present invention is 60 dB, thus reducing the total noise level of the compressor of the embodiment of the present invention by 12% compared to the prior art.

[0038] Preferably, the ratio of the thickness of the first magnetic shielding part 41 to the thickness of the second magnetic shielding part 42 is in the range of 0.5 to 0.9, preferably 0.7. When the ratio is less than 0.5, the thickness of the first magnetic shielding part 41 and the thickness of the second magnetic shielding part 42 differs too much, which affects the distribution of magnetic reluctance and fails to improve the air gap magnetic field distribution and magnetic flux direction. When the ratio is greater than 0.9, the thickness of the first magnetic shielding part 41 and the thickness of the second magnetic shielding part 42 are not significantly different, and the distribution of magnetic reluctance is also not affected, thus failing to improve the air gap magnetic field distribution and magnetic flux direction. Only when the ratio is between 0.5 and 0.9 can the uniform distribution of magnetic reluctance be guaranteed, thereby improving the air gap magnetic field distribution and magnetic flux direction, and effectively reducing the motor torque pulsation, the peak electromagnetic force of the motor, and the electromagnetic vibration noise of the motor. The thickness refers to the distance between the corresponding part at the end of the magnetic shielding groove 2 and the outer surface of the rotor, such as... Figure 1 As shown.

[0039] The width C of the first magnetic shielding section 41 and the width D of the second magnetic shielding section 42 are related by the condition 1 ≤ C / D ≤ 1.5, for example, C / D = 1.25. If the width of the second magnetic shielding section 42 is too large, it will increase the leakage flux of the permanent magnet and reduce efficiency. Only by controlling the magnetic flux through the second magnetic shielding section 42 within the range of 1 ≤ C / D ≤ 1.5 can the peak electromagnetic force of the motor be further reduced, and the electromagnetic vibration noise of the motor be reduced. Here, the width refers to the chord length of the outer surface of the rotor occupied by the end of the magnetic shielding groove 2 when it extends to the outer surface of the rotor.

[0040] In one embodiment, the magnetic slot 2 includes an outer magnetic slot 21 and an inner magnetic slot 22. The inner magnetic slot 22 is located between the outer magnetic slot 21 and the shaft hole 3. A magnetic isolation bridge 4 is formed between the end of the outer magnetic slot 21 and the outer surface of the rotor core 1, and a magnetic isolation bridge 4 is also formed between the end of the inner magnetic slot 22 and the outer surface of the rotor core 1. By fixing the permanent magnets using both the outer magnetic slot 21 and the inner magnetic slot 22, the number of permanent magnets on the rotor core 1 is increased, thereby ensuring the effective magnetic flux of the rotor.

[0041] An external magnetic bridge 43 is formed between the end of the outer magnetic groove 21 and the outer surface of the rotor core 1. The external magnetic bridge 43 includes a first external magnetic shielding part 431 and a second external magnetic shielding part 432. The thickness of the first external magnetic shielding part 431 is less than that of the second external magnetic shielding part 432. An internal magnetic bridge 44 is formed between the end of the inner magnetic groove 22 and the outer surface of the rotor core 1. The internal magnetic bridge 44 includes a first internal magnetic shielding part 441 and a second internal magnetic shielding part 442. The thickness of the first internal magnetic shielding part 441 is less than that of the second internal magnetic shielding part 442. The ratio of the thickness G of the first external magnetic shielding part 431 to the thickness A of the first internal magnetic shielding part 441 is in the range of 0.5 ≤ G / A ≤ 0.9. Preferably, G / A is 0.7. Since the permanent magnet in the outer magnetic groove 21 is closer to the air gap, the magnetic flux distribution can be improved by reducing the thickness of the first external magnetic shielding part 431, thereby increasing the effective magnetic flux and thus improving the efficiency of the motor.

[0042] Optionally, the ratio of the thickness H of the second outer magnetic shielding portion 432 to the thickness B of the second inner magnetic shielding portion 442 is in the range of 0.6 ≤ H / B ≤ 0.8. Preferably, H / B is 0.7. Reducing the thickness of the second outer magnetic shielding portion 432 further improves the magnetic flux distribution, increases the effective magnetic flux, and thus improves the efficiency of the motor. The thickness refers to the distance between the corresponding portion at the end of the magnetic shielding groove 2 and the outer surface of the rotor.

[0043] The second outer magnetic shielding part 432 and the second inner magnetic shielding part 442 extend along the circumferential direction of the rotor and are close to the outer surface of the rotor, allowing more magnetic flux to pass through. At the same time, combined with the thickness distribution of the first outer magnetic shielding part 431 and the second outer magnetic shielding part 432 of the outer magnetic steel groove 21 and the first inner magnetic steel groove 22 and the second inner magnetic steel groove 22 of the inner magnetic steel groove 22, the magnetic permeability of the rotor magnetic poles in the circumferential and radial directions can be made more uniform, which can better improve the air gap magnetic field, reduce the harmonics of the air gap magnetic flux density, reduce the proportion of back EMF harmonics, reduce the peak value of electromagnetic force, and reduce the electromagnetic vibration noise of the motor.

[0044] like Figure 3 As shown, a deepened groove 5 is provided on the rotor core 1. The deepened groove 5 is located between the end of the magnet slot 2 and the outer surface of the rotor core 1, and the deepened groove 5 communicates with the magnet slot 2. The first magnetic isolation part 41 is formed between the deepened groove 5 and the outer surface of the rotor core 1. By changing the end shape of the magnet slot 2 using the deepened groove 5, the thickness of the magnetic isolation bridge 4 is changed, thereby changing the magnetic resistance distribution at various points in the motor magnetic circuit. This reduces the cogging effect of the motor, improves the magnetic flux direction, and effectively reduces the motor's torque pulsation, electromagnetic force peak value, and electromagnetic vibration noise.

[0045] The opening of the deepened groove 5 is connected to the end of the magnet slot 2, and the width of the opening of the deepened groove 5 is smaller than the width of the end of the magnet slot 2. This makes the magnetic permeability of the rotor magnetic poles more uniform in the circumferential and radial directions, better improves the air gap magnetic field distribution, reduces harmonics of the air gap magnetic flux density, reduces torque pulsation, and reduces electromagnetic vibration noise of the motor.

[0046] The width of the deepening groove 5 gradually increases from its opening to its bottom. This gradual increase in width results in a gradual increase in magnetic flux along the direction from the inner magnetic groove 22 to the outer magnetic groove 21, further enhancing the uniformity of magnetic permeability.

[0047] Preferably, the ratio of the width E of the opening of the deepening groove 5 to the width F of the bottom of the deepening groove 5 is in the range of 1.1 ≤ F / E ≤ 1.4. Preferably, F / E is 1.25.

[0048] The cross-section of the magnetic slot 2 is arc-shaped. The two ends of the arc form magnetic bridges 4 with the outer surfaces of the corresponding rotor cores. The convex direction of the arc faces the shaft hole 3.

[0049] An electric motor, comprising the rotor described above.

[0050] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A rotor, characterized in that, The rotor core includes a magnetic steel groove and a shaft hole located in the middle of the rotor core. A magnetic isolation bridge is formed between the end of the magnetic steel groove and the outer surface of the rotor core. The magnetic isolation bridge includes at least two magnetic isolation parts with different thicknesses. The magnetic isolation bridge includes a first magnetic isolation part and a second magnetic isolation part. The first magnetic isolation part and the second magnetic isolation part are arranged along the width direction of the magnetic steel groove, and the first magnetic isolation part is located on the side of the second magnetic isolation part away from the rotating shaft hole. The thickness of the first magnetic isolation part is less than the thickness of the second magnetic isolation part. The rotor core is provided with a deep groove, which is located between the end of the magnet slot and the outer surface of the rotor core, and the deep groove is connected to the magnet slot. The first magnetic isolation part is formed between the deep groove and the outer surface of the rotor core. The width of the deepening groove gradually increases along the direction from the opening of the deepening groove to the bottom of the deepening groove; the ratio of the width E of the opening of the deepening groove to the width F of the bottom of the deepening groove is in the range of 1.1≤F / E≤1.

4.

2. The rotor according to claim 1, characterized in that, The ratio of the thickness of the first magnetic shielding part to the thickness of the second magnetic shielding part ranges from 0.5 to 0.

9.

3. The rotor according to claim 1, characterized in that, The relationship between the width C of the first magnetic shielding part and the width D of the second magnetic shielding part is 1≤C / D≤1.

5.

4. The rotor according to claim 1, characterized in that, The magnetic steel groove includes an outer magnetic steel groove and an inner magnetic steel groove. The inner magnetic steel groove is located between the outer magnetic steel groove and the shaft hole. One of the magnetic isolation bridges is formed between the end of the outer magnetic steel groove and the outer surface of the rotor core, and the other magnetic isolation bridge is formed between the end of the inner magnetic steel groove and the outer surface of the rotor core.

5. The rotor according to claim 4, characterized in that, An external magnetic bridge is formed between the end of the outer magnetic steel slot and the outer surface of the rotor core. The external magnetic bridge includes a first external magnetic shielding part and a second external magnetic shielding part. The thickness of the first external magnetic shielding part is less than that of the second external magnetic shielding part. An internal magnetic bridge is formed between the end of the inner magnetic steel slot and the outer surface of the rotor core. The internal magnetic bridge includes a first internal magnetic shielding part and a second internal magnetic shielding part. The thickness of the first internal magnetic shielding part is less than that of the second internal magnetic shielding part. The ratio of the thickness G of the first external magnetic shielding part to the thickness A of the first internal magnetic shielding part is in the range of 0.5 ≤ G / A ≤ 0.9; and / or, the ratio of the thickness H of the second external magnetic shielding part to the thickness B of the second internal magnetic shielding part is in the range of 0.6 ≤ H / B ≤ 0.

8.

6. The rotor according to claim 1, characterized in that, The opening of the deepening groove is connected to the end of the magnet groove, and the width of the opening of the deepening groove is smaller than the width of the end of the magnet groove.

7. The rotor according to claim 1, characterized in that: The cross-section of the magnetic steel groove is arc-shaped.

8. An electric motor, characterized in that: The rotor includes any one of claims 1 to 7.

9. A compressor, characterized in that: It includes the rotor of any one of claims 1 to 7 or the motor of claim 8.

Images