Rotor core, motor, compressor

Abstract

The present invention provides a rotor core, a motor, and a compressor, wherein the rotor core includes a core body, the core body has a plurality of magnetic steel slots in the circumferential direction, an air magnetic isolation slot is provided at the radial outer end of the magnetic steel slot, the air magnetic isolation slot is connected with the magnetic steel slot and the air magnetic isolation slot extends along the circumferential direction of the core body, when the magnetic steel is embedded in the magnetic steel slot, the air magnetic isolation slot is divided into a first slot section and a second slot section, the first slot section and the second slot section are respectively located on opposite sides of the magnetic steel, wherein the second slot section is connected with the outer peripheral wall of the core body through a gap provided on the radial outer slot wall thereof. According to the present invention, by providing the air magnetic isolation slot at the radial outer end of the magnetic steel slot and using the gap to connect the air magnetic isolation slot with the outer peripheral wall of the core body, the magnetic circuit direction can be changed, thereby changing the electromagnetic force amplitude and the motor torque of the motor, optimizing the air gap magnetic density waveform, and facilitating the rational design of the q-axis inductance size and the mechanical strength of the rotor.

Description

Technical Field

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

[0002] In response to the national policy of high efficiency and energy conservation, compressor efficiency has become a trend. The core component of the compressor is the motor. The efficiency and noise of the motor directly affect the overall performance of the compressor. To meet the energy-saving requirements, the higher the motor efficiency, the better. To improve the user experience, the lower the motor noise, the better. However, the efficiency and noise of the motor restrict each other. Improving motor efficiency and reducing motor vibration noise are often contradictory. Therefore, high-efficiency and low-noise motors have become the research goal of the industry. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is to provide a rotor core, a motor, and a compressor. By arranging an air magnetic isolation groove at the radial outer end of the magnetic steel groove and using a gap to connect the air magnetic isolation groove and the outer peripheral wall of the core body, the direction of the magnetic circuit can be changed, thereby changing the electromagnetic force amplitude and the motor torque of the motor, optimizing the air gap magnetic density waveform, and facilitating the rational design of the q-axis inductance and the mechanical strength of the rotor.

[0004] In order to solve the above problems, the present invention provides a rotor core, including a core body, on any radial cross-section of the core body, the core body has a plurality of magnetic steel slots in the circumferential direction, the plurality of magnetic steel slots are used to embed magnetic steel to form uniformly alternating magnetic poles in the circumferential direction of the rotor core, and air magnetic isolation slots are provided at the radial outer ends of the magnetic steel slots, a penetration is formed between the air magnetic isolation slots and the magnetic steel slots, and the air magnetic isolation slots extend along the circumferential direction of the core body, when the magnetic steel is embedded in the magnetic steel slots, the air magnetic isolation slots are divided into a first slot segment and a second slot segment, the first slot segment and the second slot segment are respectively located on opposite sides of the magnetic steel, wherein the second slot segment is connected to the outer circumferential wall of the core body through a gap arranged on the radial outer slot wall thereof.

[0005] Preferably, the minimum width of the gap is c, 0.45 mm <c<0.85mm。

[0006] Preferably, the second slot segments respectively provided in two adjacent magnetic poles are symmetrical about the q axis between the two adjacent magnetic poles and form a pole spacing magnetic bridge, the minimum circumferential width of the pole spacing magnetic bridge is a, and the number of pole pairs of the magnetic poles provided in the rotor core is p, π / 5*1 / p-1 / 2*p*p <a<3*π*1 / p-1 / 2*p*p。

[0007] Preferably, an included angle r is formed between the slot and the q-axis. The minimum distance between the slot wall at the end of the first slot section away from the q-axis and the permanent magnet is f, the minimum distance between the slot wall at the end of the second slot section close to the q-axis and the permanent magnet is e, and the minimum distance between the intersection of the slot and the second slot section close to the q-axis and the q-axis is d, where d*sinr / 4 < e + f < 5*d / sinr.

[0008] Preferably, the air magnetic isolation slot has a minimum width b in the radial direction of the iron core body, and the thickness of the permanent magnet is h, where h / 5 < b < 2h.

[0009] Preferably, the effective value of the air-gap magnetic density of the motor is B, where a / 5 < B < h; and / or, the leakage magnetic coefficient between rotor poles is k, where a / 4 < k < 3h; and / or, the q-axis inductance of the motor is L, where b / 5 < L < 10a.

[0010] Preferably, the circumferential slot wall of the second slot section close to the q-axis is a convex character stepped structure, and the side of the convex character stepped structure facing the q-axis protrudes.

[0011] Preferably, the peripheral wall of the air magnetic isolation slot is formed by connecting multiple straight line segments and / or arc segments.

[0012] The present invention also provides a motor, including the above-mentioned rotor iron core assembly.

[0013] The present invention also provides a compressor, including the above-mentioned motor.

[0014] A rotor iron core, a motor, and a compressor provided by the present invention can change the magnetic circuit direction by arranging an air magnetic isolation slot at the outer end in the radial direction of the permanent magnet slot and penetrating the air magnetic isolation slot and the outer peripheral wall of the iron core body with a slot, making the air-gap magnetic density near the magnetic poles more sinusoidal, reducing the harmonic content, also decreasing the electromagnetic force amplitude of the motor, enhancing the effective torque, and being beneficial to the rational design of the q-axis inductance value and the mechanical strength of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of a rotor iron core according to an embodiment of the present invention;

[0016] Figure 2 is Figure 1 a partial enlarged view at A in

[0017] Figure 3 is a partial structural schematic diagram of a rotor iron core according to another embodiment of the present invention;

[0018] Figure 4 is a schematic diagram of the stator-rotor structure of a motor according to an embodiment of the present invention;

[0019] Figure 5 A schematic diagram of the stator and rotor structure of a motor according to another embodiment of the present invention;

[0020] Figure 6 This is a comparison diagram of electromagnetic radial force between the new motor and the existing motor;

[0021] Figure 7 This is a comparison chart of the motor efficiency between the new motor and the existing motor;

[0022] Figure 8 This is a noise comparison chart between the new compressor and the existing compressor;

[0023] Fig. 9 This is a comparison chart of the iron loss of the new motor and the existing motor.

[0024] The reference numerals are:

[0025] 1. Iron core body; 11. Magnetic steel slot; 12. Air magnetic isolation slot; 121. First slot section; 122. Second slot section; 13. Gap; 14. Inter-pole spacing magnetic bridge; 2. Magnetic steel; 200. Motor stator. DETAILED DESCRIPTION

[0026] See also Figures 1 to 9As shown, according to an embodiment of the present invention, a rotor core is provided, including a core body 1. On any radial cross-section of the core body 1, a plurality of magnet slots 11 are provided in the circumferential direction (i.e., the circumferential direction) of the core body 1. The plurality of magnet slots 11 are used for installing magnets 2 to form uniformly alternating magnetic poles in the circumferential direction of the rotor core. An air magnetic isolation slot 12 is provided at the radially outer end of the magnet slot 11. A through connection is formed between the air magnetic isolation slot 12 and the magnet slot 11, and the air magnetic isolation slot 12 extends along the circumferential direction of the core body 1. When the magnet 2 is installed in the magnet slot 11, the air magnetic isolation slot 12 is divided into a first slot section 121 and a second slot section 122. The first slot section 121 and the second slot section 122 are respectively on opposite sides of the magnet 2. Among them, the second slot section 122 communicates with the outer peripheral wall of the core body 1 through a slit 13 provided on its radially outer side wall. In this technical solution, by providing the air magnetic isolation slot 12 at the radially outer end of the magnet slot 11 and using the slit 13 to communicate the air magnetic isolation slot 12 with the outer peripheral wall of the core body 1, the magnetic circuit direction can be changed, making the air-gap magnetic density near the magnetic poles more sinusoidal, reducing the harmonic content, and also decreasing the electromagnetic force amplitude of the motor, and effectively improving the torque. This is beneficial to the rational design of the q-axis inductance value and the mechanical strength of the rotor. More specifically, as a structural form of the air magnetic isolation slot 12, it is generally approximately in the shape of a "one-word" as a whole. The "one-word" air magnetic isolation slot 12 and the magnet slot 11 are generally in a T-shaped structure as a whole. When the magnet 2 is installed in the magnet slot 11, the "one-word" air magnetic isolation slot 12 is divided into two parts located on opposite sides of the magnet 2.

[0027] The local structure of the air magnetic isolation slot 12 can be adjusted and optimized. In some embodiments, as Figure 3 shown, the circumferential side wall of the second slot section 122 near the q-axis is a convex-character stepped structure, and the side of the convex-character stepped structure protruding towards the q-axis can further optimize the air-gap magnetic density waveform of the motor. Considering the processability, the air magnetic isolation slot 12 can also be adjusted to be quadrilateral. Of course, the peripheral wall of the air magnetic isolation slot 12 is formed by connecting multiple straight line segments and / or arc line segments.

[0028] The minimum width of the slit 13 is c, where 0.45 mm < c < 0.85 mm, to ensure the mechanical strength of the rotor and reduce the torque ripple of the motor.

[0029] The inventor found that for a 9-slot 6-pole concentrated winding motor, the amplitude of the 0th-order 18th harmonic electromagnetic force, the q-axis inductance value, and the mechanical strength of the rotor all increase with the increase of the pole pitch width. The motor efficiency first increases and then decreases with the increase of the pole pitch width. However, the increase in the amplitude of the 0th-order 18th harmonic electromagnetic force of the motor will affect the vibration and noise of the motor. When the pole pitch width of the rotor is too large, it will increase the leakage flux and reduce the motor efficiency. Therefore, it is necessary to limit the pole pitch width of the motor. Specifically, in some embodiments, the second slot segments 122 respectively provided in two adjacent magnetic poles are symmetric about the q-axis between the two adjacent magnetic poles and form a pole interval magnetic bridge 14. The minimum circumferential width of the pole interval magnetic bridge 14 (i.e., the width in the circumferential direction of the rotor body 1) is a, and the number of pole pairs of the magnetic poles of the rotor core is p, where π / 5 * 1 / p - 1 / 2 * p * p < a < 3 * π * 1 / p - 1 / 2 * p * p. In this technical solution, the a is the aforementioned pole pitch width. By limiting the pole pitch width, the electromagnetic force of the motor can be reduced, the q-axis inductance can be increased, the reluctance torque of the motor can be improved, the motor efficiency can be increased, the magnetic circuit of the motor can be further optimized, the magnitude of the output torque of the motor is not affected, the harmonic content in the air-gap magnetic density can be reduced, the iron loss of the motor can be further reduced, the motor efficiency can be increased, and the vibration and noise of the motor can be reduced, thereby reducing the overall noise of the compressor. Specifically, if a < π / 5 * (1 / p - 1 / 2 * p * p), the width between adjacent magnetic poles is too narrow, which will cause insufficient mechanical strength of the rotor. When the rotor rotates, it will break due to the influence of centrifugal force, resulting in motor damage. The narrow width between adjacent magnetic poles will also reduce the q-axis inductance of the motor; if a > 3 * π * (1 / p - 1 / 2 * p * p), the width between adjacent magnetic poles is too large, which will cause excessive leakage flux between magnetic poles and shorten the length of the permanent magnet, reduce the amplitude of the air-gap magnetic density, and reduce the output torque and efficiency of the motor.

[0030] Preferably, an included angle r is formed between the gap 13 and the q-axis. The minimum distance between the end wall of the first slot segment 121 away from the q-axis and the permanent magnet 2 is f. The minimum distance between the end wall of the second slot segment 122 close to the q-axis and the permanent magnet 2 is e. The minimum distance between the intersection point of the gap 13 and the second slot segment 122 close to the q-axis and the q-axis is d, and d * sinr / 4 < e + f < 5 * d / sinr. If e + f exceeds this range, the motor efficiency will be reduced and the vibration and noise of the motor will increase.

[0031] Preferably, the air magnetic isolation groove 12 has a minimum width b in the radial direction of the iron core body 1, and the thickness of the permanent magnet 2 is h (it can be understood that h here refers to the width of the permanent magnet 2 in the radial cross-section of the iron core body 1 and in its circumferential direction), h / 5 < b < 2h. If b < h / 5, the width of the air magnetic isolation groove 12 is too small to achieve the effect of magnetic isolation; if b > 2h, the width of the air magnetic isolation groove 12 is too large, which will affect the magnitude of the air-gap magnetic density of the motor and reduce the motor efficiency.

[0032] Preferably, the effective value of the air-gap magnetic density of the motor is B, a / 5 < B < h. If B < a / 5, the effective value of the magnetic density in the middle of the motor air gap is too small, the magnetic load design of the motor is too small, and the motor design is unreasonable. If B > h, the effective value of the magnetic density in the middle of the motor air gap is too large, the magnetic circuit of the motor is severely saturated, the iron loss ratio of the motor is too large, and the utilization rate of the permanent magnet material is too low, resulting in material waste.

[0033] And / or, the inter-pole leakage magnetic coefficient of the rotor is k, a / 4 < k < 3h. If k < a / 4, the inter-pole leakage magnetic coefficient of the rotor is too small, which will lead to poor demagnetization resistance of the permanent magnet and there is a risk of demagnetization during motor operation; if k > 5h, the inter-pole leakage magnetic coefficient of the rotor is too large, the inter-pole leakage of the rotor is too large, and the utilization rate of the permanent magnet material is too low, resulting in material waste.

[0034] And / or, the q-axis inductance of the motor is L, b / 5 < L < 10a. If L < b / 5, the inductance of the q-axis of the motor is too small, the field-weakening speed regulation range of the motor is very narrow, the reluctance torque of the motor is also very small, and the motor efficiency is low; if L > 10a, the inductance of the q-axis of the motor is too large, which will cause the torque angle to be too large when the motor outputs torque, and the vibration and noise of the motor will also increase.

[0035] The present invention also provides a motor, including the above-mentioned rotor core assembly. Specifically, the rotor core assembly is located in the central through hole of the motor stator 200, and an air gap is formed between the two. The motor can be Figure 4 the concentrated winding motor structure shown, or can also be Figure 5 the distributed winding motor structure shown.

[0036] The present invention also provides a compressor, including the above-mentioned motor.

[0037] In order to verify the technical effects of the technical solution of the present application, the inventor conducted relevant tests and obtained:

[0038] (1) As Figure 6 shown, the electromagnetic radial force of the motor (marked as the new motor in the figure) adopting the technical solution of the present application is significantly smaller than that of the motor in the prior art (marked as the existing motor in the figure);

[0039] (2) As Figure 7As shown, the motor efficiency of the motor using the technical solution of the present application (marked as a new motor in the figure) is significantly higher than the motor efficiency of the motor in the prior art (marked as an existing motor in the figure);

[0040] (3) Figure 8 As shown, the total noise value of the compressor using the motor of the technical solution of the present application (marked as a new compressor in the figure) is significantly lower than the total noise value of the compressor using the motor in the prior art (marked as an existing compressor in the figure);

[0041] (4) Fig. 9 As shown, the iron loss of the motor (marked as a new motor in the figure) using the technical solution of the present application is significantly lower than the iron loss of the motor in the prior art (marked as an existing motor in the figure).

[0042] 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.

[0043] The above are only 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 in the protection scope of the present invention. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A rotor core, characterized in that: It includes an iron core body (1). On any radial cross-section of the iron core body (1), there are multiple magnet slots (11) in the circumferential direction of the iron core body (1). The multiple magnet slots (11) are used to install magnets (2) to form uniformly alternating magnetic poles in the circumferential direction of the rotor iron core. An air magnetic isolation slot (12) is provided at the radially outer end of the magnet slot (11). A through connection is formed between the air magnetic isolation slot (12) and the magnet slot (11), and the air magnetic isolation slot (12) extends along the circumferential direction of the iron core body (1). When the magnet (2) is installed in the magnet slot (11), the air magnetic isolation slot (12) is divided into a first slot section (121) and a second slot section (122). The first slot section (121) and the second slot section (122) are respectively on opposite sides of the magnet (2). Among them, the second slot section (122) communicates with the outer peripheral wall of the iron core body (1) through a gap (13) provided on its radially outer slot wall; the circumferential wall of the air magnetic isolation slot (12) is formed by connecting multiple straight line segments and / or arc line segments; the second slot sections (122) respectively included in two adjacent magnetic poles are symmetric about the q-axis between the two adjacent magnetic poles and form a pole interval magnetic bridge (14). The minimum circumferential width of the pole interval magnetic bridge (14) is a, and the number of pole pairs of the magnetic poles of the rotor iron core is p, π / 5*(1 / p - 1 / 2*p*p) < a < 3*π*(1 / p - 1 / 2*p*p).

2. The rotor core according to claim 1, characterized in that: The minimum width of the gap (13) is c, 0.45mm < c < 0.85mm.

3. The rotor core according to claim 1, characterized in that: An angle r is formed between the gap (13) and the q-axis. The minimum distance between the slot wall at the end of the first slot section (121) far from the q-axis and the magnet (2) is f. The minimum distance between the slot wall at the end of the second slot section (122) close to the q-axis and the magnet (2) is e. The minimum distance between the intersection point of the gap (13) and the second slot section (122) close to the q-axis and the q-axis is d, d*sinr / 4 < e + f < 5*d / sinr.

4. The rotor core according to any one of claims 1 to 3, characterized in that: The air magnetic isolation slot (12) has a minimum width b in the radial direction of the iron core body (1). The thickness of the magnet (2) is h, h / 5 < b < 2h.

5. The rotor core according to claim 4, characterized in that: The effective value of the air-gap magnetic density of the motor is B, a / 5 < B < h; and / or, the rotor pole leakage magnetic coefficient is k, a / 4 < k < 3h; and / or, the motor q-axis inductance is L, b / 5 < L < 10a.

6. The rotor core according to claim 1, characterized in that: The circumferential slot wall of the second slot section (122) close to the q-axis is a convex character stepped structure, and the side of the convex character stepped structure facing the q-axis protrudes.

7. A motor, comprising a rotor core assembly, characterized in that: The rotor iron core assembly is the rotor iron core according to any one of claims 1 to 6.

8. A compressor, comprising a motor, characterized in that: The motor is the motor according to claim 7.

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