CN205647074U - Rotor core , rotor, motor and compressor - Google Patents

Abstract

The utility model discloses a rotor iron core, a rotor, a motor and a compressor. The outer contour of the rotor core includes a d-axis arc segment, a q-axis arc segment and several connecting segments. The center of the d-axis arc segment coincides with the center of the rotor core and the d-axis of the rotor core passes through the d-axis arc the center of the q-axis arc segment; the center of the q-axis arc segment coincides with the center of the rotor core and the q-axis of the rotor core passes through the center of the q-axis arc segment; several connecting segments are connected between the adjacent d-axis arc segment and the q-axis Between the arc segments, at least one of the connecting segments is arc-shaped with the center of the circle located outside the rotor core and arranged adjacent to the q-axis, wherein the radius of the arc segment on the d-axis is Rd, and the radius of the arc segment on the q-axis is Rq, 0.9<Rq/Rd≤1. The rotor iron core according to the utility model can not only reduce the harmonic content of the air-gap magnetic density, but also has a simple structure, is easy to manufacture and produce, has a high yield, and can improve the performance of the motor running under the magnetic field weakening condition.

Description

Rotor cores, rotors, motors and compressors

technical field

The utility model relates to the technical field of motors, in particular to a rotor core, a rotor with the rotor core, a motor with the rotor and a compressor with the motor.

Background technique

In the permanent magnet embedded motors in the related art, some of them have relatively large vibration and noise, others have complex structures, are difficult to manufacture and produce, and have a low yield rate, and the direct-axis inductance and quadrature-axis inductance of the motor are small, which affects the motor. Performance under field weakening operating conditions.

Utility model content

The utility model aims at at least solving one of the technical problems existing in the prior art. For this reason, the utility model needs to provide a kind of rotor iron core, and described rotor iron core can not only optimize the distribution of air-gap magnetic density, reduce the harmonic content of air-gap magnetic density, and simple in structure, easy to manufacture and produce, yield At the same time, it can increase the direct-axis inductance value and quadrature-axis inductance value of the motor, and improve the performance of the motor running under the condition of weak magnetic field.

The utility model also needs to provide a rotor with the rotor core.

The utility model also needs to provide a motor with the rotor.

The utility model also needs to provide a compressor with the motor.

According to the rotor core of the embodiment of the first aspect of the present invention, the rotor core is provided with a plurality of magnetic pole slots arranged at intervals along the circumferential direction of the rotor core. In the plane of , the outer contour of the rotor core includes: a d-axis arc segment, the center of the d-axis arc segment coincides with the center of the rotor core and the d-axis of the rotor core passes through the The center of the d-axis arc segment; the q-axis arc segment, the center of the q-axis arc segment coincides with the center of the rotor core and the q-axis of the rotor core passes through the q-axis arc The center of the segment; several connecting segments, the connecting segments are connected between the adjacent d-axis arc segments and the q-axis arc segments, at least one of the several connecting segments is located at the center of the rotor The outer side of the iron core is arc-shaped and arranged adjacent to the q-axis, wherein the radius of the d-axis arc segment is Rd, the radius of the q-axis arc segment is Rq, and 0.9<Rq/Rd≤1.

According to the rotor core of the embodiment of the utility model, by designing Rq/Rd in the range of 0.9 to 1 and designing the outer contour of the rotor core into a shape with concave characteristics, not only the distribution of the air gap magnetic density of the motor can be optimized, Make the motor have lower air-gap magnetic density harmonic content, reduce the electromagnetic excitation of the motor, and have a simple structure, which is convenient for manufacturing and production; at the same time, the inductance of the direct axis and the quadrature axis of the motor is relatively large, and the motor is The performance is good.

In addition, the rotor core according to the embodiment of the utility model also has the following additional technical features:

According to some embodiments of the present invention, the included angle between the adjacent d-axis and the q-axis is α, and the center of one of the arc-shaped connecting segments closest to the q-axis and the The included angle between the imaginary line connecting the center of the rotor core and the q-axis is α1, 0.16≦α1/α<0.45.

According to some embodiments of the present invention, the area enclosed by the outer contour of the rotor core is S1, the area of the circle where the d-axis arc segment is located is S2, and 0.95<S1/S2<0.99.

According to some embodiments of the present invention, the minimum distance between adjacent magnetic pole slots is less than 1 mm.

According to some embodiments of the present invention, a non-punching area is formed between the magnetic pole slot and the outer contour of the rotor core.

According to some embodiments of the present utility model, the minimum distance between the magnetic pole slots and the outer contour of the rotor core is less than 0.8mm.

According to some embodiments of the present utility model, the distance between the center of the magnetic pole slot and the center of the rotor core is larger than 0.8Rd and smaller than Rq.

According to some embodiments of the present invention, there are six magnetic pole slots and they respectively extend along six sides of the same regular hexagon.

According to some embodiments of the present utility model, the rotor core is formed by laminating a plurality of electromagnetic steel plates with a thickness of 0.3 mm.

According to some embodiments of the present utility model, at least one of the several connecting sections is straight.

The rotor according to the embodiment of the second aspect of the utility model includes: the rotor core according to the embodiment of the first aspect of the utility model; a plurality of permanent magnets, and the plurality of permanent magnets are respectively installed in the plurality of magnetic pole slots Inside.

According to the rotor of the embodiment of the present invention, by using the above-mentioned rotor core, the motor can not only have a lower air-gap magnetic density harmonic content, but also has a simple structure, is easy to manufacture and produce, and has a high yield. In addition, the rotor can increase the direct-axis inductance value and the quadrature-axis inductance value of the motor, and improve the performance of the motor running under a magnetic field weakening condition.

Preferably, the permanent magnet is a rare earth permanent magnet with a remanence greater than 1.25T and a coercive force greater than 900kA/m.

The motor according to the embodiment of the third aspect of the utility model includes the rotor according to the embodiment of the second aspect of the utility model.

According to the motor of the embodiment of the present invention, using the above-mentioned rotor, the distribution of the air-gap magnetic density is better, and the harmonic content of the air-gap magnetic density is less, so that the electromagnetic excitation is relatively small, the vibration and noise are small, and the structure is simple. Easy to manufacture and produce. In addition, the direct-axis inductance and quadrature-axis inductance of the motor are relatively large, and the performance is good under the condition of field weakening.

The compressor according to the embodiment of the fourth aspect of the utility model includes the motor according to the embodiment of the third aspect of the utility model.

According to the compressor of the embodiment of the present invention, the above-mentioned motor is used, and the vibration and noise are small and the energy efficiency is high.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

Fig. 1 is a schematic structural view of a rotor core according to an embodiment of the present invention;

Fig. 2 is a schematic structural view of a rotor core according to an optional embodiment of the present invention;

Fig. 3 is a partial structural schematic diagram of a motor according to an embodiment of the present invention;

Fig. 4 is a schematic diagram of the air-gap magnetic density distribution waveform of the motor according to the embodiment of the present invention;

Fig. 5 is a schematic diagram of the air-gap flux density harmonic content of the motor according to the embodiment of the present invention.

Reference signs:

motor 1,

rotor 10, stator 20,

Rotor core 100, magnetic pole slot 101, rivet hole 102, d-axis arc section 110, q-axis arc section 120, connection section 130, arc-shaped connection section 131, straight line connection section 132,

permanent magnet 200 .

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present utility model, but should not be construed as limiting the present utility model.

This application is made based on the inventor's discovery and understanding of the following facts and problems:

The permanent magnet embedded motor in the related art has relatively large vibration and noise, especially the permanent magnet embedded motor with fractional slots. Due to the high harmonic content in the air gap, the vibration and noise are often higher than that of the permanent magnet embedded motor with integer slots. The built-in motor is larger. When the permanent magnet embedded motor is used as the driving motor of the variable frequency compressor, since the electromagnetic excitation of the motor stator will be directly transmitted to the main casing, the electromagnetic excitation and vibration of the rotor will be transmitted to the outside of the compressor through components such as the crankshaft and bearings, thereby generate electromagnetic noise. In addition, when the compressor is installed on the air-conditioning system, due to the existence of damping, high-frequency noise is filtered out, but lower-frequency noise and vibration will be transmitted through the sheet metal of the air conditioner and radiated outward, and relatively Low-frequency vibration will cause the vibration of the pipeline system, and finally make the vibration and noise of the entire air conditioning system large.

When designing motors in the related art, the distribution of the air-gap flux density is often optimized, and the harmonic content of the air-gap flux density is reduced as much as possible, but this will lead to complex rotor structures, high manufacturing and production difficulties, and low The efficiency is low, and the direct-axis inductance and quadrature-axis inductance of the motor are small, which affects the performance of the motor under field-weakening operating conditions.

For this reason, the utility model proposes a rotor core 100, which can not only optimize the distribution of the air-gap flux density, reduce the harmonic content of the air-gap flux density, but also has a simple structure, is easy to manufacture and produce, and has a high yield rate. At the same time, it can increase the direct-axis inductance value and quadrature-axis inductance value of the motor, and improve the performance of the motor running under the condition of weak magnetic field.

The following describes a rotor core 100 according to an embodiment of the first aspect of the present invention with reference to FIGS. 1-5 .

As shown in Figures 1 to 5, according to the rotor core 100 of the embodiment of the present invention, the rotor core 100 is provided with a plurality of magnetic pole slots 101 arranged at intervals along the circumferential direction of the rotor core 100. In the plane of the central axis of the core 100 , the outer contour of the rotor core 100 includes a d-axis arc segment 110 , a q-axis arc segment 120 and several connecting segments 130 .

The following descriptions of the outer contour of the rotor core 100 are all taken as examples in a plane perpendicular to the central axis of the rotor core 100 . Those skilled in the art can understand that the d-axis of the rotor core 100 is a straight axis, that is, an axis that simultaneously passes through the center of the rotor core 100 and the center of the length direction of the magnetic pole slot 101 and is perpendicular to the length direction of the magnetic pole slot 101 , the q-axis of the rotor core 100 is a quadrature axis, that is, an axis passing through the center of the rotor core 100 and the center between adjacent magnetic pole slots 101 at the same time.

Specifically, the center of the d-axis arc segment 110 coincides with the center of the rotor core 100 , and the d-axis of the rotor core 100 passes through the center of the d-axis arc segment 110 . The center of the q-axis arc segment 120 coincides with the center of the rotor core 100 , and the q-axis of the rotor core 100 passes through the center of the q-axis arc segment 120 . Several connection sections 130 are connected between adjacent d-axis arc sections 110 and q-axis arc sections 120, at least one of the several connection sections 130 is in the shape of an arc whose center is located outside the rotor core 100, and the center of the circle is located at the rotor core 100. The arc-shaped connecting section 131 on the outer side of the iron core 100 is arranged adjacent to the q-axis. Wherein, the radius of the d-axis arc segment 110 is Rd, the radius of the q-axis arc segment 120 is Rq, and 0.9<Rq/Rd≤1.

It should be noted that, in the circumferential direction of the rotor core 100, the d-axis circular arc segment 110, several connecting segments 130 and the q-axis circular arc segment 120 are sequentially connected circularly to form the outer contour of the rotor core 100, and the several connecting segments 130 At least one of them is in the shape of an arc whose center is located outside the rotor core 100 , so that the outer contour of the rotor core 100 has a concave feature.

It can be understood that "several" includes one and more, and several connecting sections 130 include two situations: one connecting section 130 and multiple connecting sections 130; It can be understood that one of the several connecting sections 130 is in the shape of an arc whose circle center is located outside the rotor core 100 , or a plurality of the several connecting sections 130 are all in the shape of an arc whose circle center is located outside the rotor core 100 .

According to the rotor core 100 of the embodiment of the present utility model, by designing Rq/Rd in the range of 0.9 to 1 and designing the outer contour of the rotor core 100 into a shape with concave characteristics, not only the air gap flux density of the motor can be optimized distribution, so that the motor has a lower air-gap flux density harmonic content, reducing the electromagnetic excitation of the motor, and the rotor core 100 is simple in structure, easy to manufacture and produce; at the same time, the d-axis (ie, the direct axis) and The inductance of the q-axis (that is, the quadrature axis) is relatively large, and the performance of the motor under weak magnetic field is good.

Wherein, Fig. 4 is the air-gap magnetic density distribution waveform of the motor adopting the rotor core 100 of the utility model embodiment, and the air gap flux density distribution of the motor is better; Fig. 5 is the rotor core adopting the utility model embodiment The air-gap flux density harmonic content of the motor is 100, and the air-gap flux density harmonic content of the motor is relatively low.

Preferably, the area enclosed by the outer contour of the rotor core 100 is S1, the area of the circle where the d-axis arc segment 110 is located is S2, 0.95<S1/S2<0.99, so as to simplify the structure of the rotor core 100.

According to some embodiments of the present invention, as shown in FIG. 1 and FIG. 2 , the included angle between adjacent d-axes and q-axes is α, and the center of the circle is located at the arc-shaped connecting section 130 outside the rotor core 100 The angle between the imaginary line between the center of the nearest q-axis and the center of the rotor core 100 and the q-axis is α1, that is, the circle center closest to the q-axis is located in the circular arc connection outside the rotor core 100 The included angle between the imaginary line connecting the center of the segment 131 and the center of the rotor core 100 and the q-axis is α1, 0.16≦α1/α<0.45. As a result, the air gap magnetic density distribution is further optimized, and the harmonic content of the air gap magnetic density is further reduced.

According to some embodiments of the present invention, the minimum distance between adjacent magnetic pole slots 101 is less than 1 mm. In other words, the magnetic pole slots 101 are closed slots. In the circumferential direction of the rotor core 100, the part of the rotor core 100 between adjacent magnetic pole slots 101 forms a magnetic isolation bridge. The width is less than 1mm. In this way, the flux leakage can be reduced, the main flux can be increased, and the absolute value of the flux density can be increased.

According to some embodiments of the present invention, the minimum distance between the magnetic pole slots 101 and the outer contour of the rotor core 100 is less than 0.8mm. For example, the magnetic pole slot 101 is generally elongated, and the two ends of the magnetic pole slot 101 respectively extend along the circumferential direction of the rotor core 100, and the part of the rotor core 100 located outside the magnetic pole slot 101 in the radial direction of the rotor core 100 forms a magnetic bridge, the width of the magnetic bridge in the radial direction of the rotor core 100 is less than 0.8 mm. In this way, better air-gap magnetic density distribution and smaller air-gap magnetic density harmonic content are guaranteed.

According to some embodiments of the present utility model, as shown in FIGS. 1-3 , a non-punching area is formed between the magnetic pole slot 101 and the outer contour of the rotor core 100 . In other words, the portion between the outer contour of the rotor core 100 and the outer edge of the pole slot 101 in the radial direction of the rotor core 100 is solid without any slits or punching features such as circles or rectangles. In this way, the manufacture is simple, the yield is high, and the mechanical strength of the rotor core 100 is high, which is beneficial to the high-speed operation of the motor and the high-frequency operation of the compressor. Preferably, the distance between the center of the magnetic pole slot 101 and the center of the rotor core 100 is greater than 0.8Rd and less than Rq, so as to reduce the harmonic content of the air gap flux density.

In some embodiments shown in FIGS. 1-3 , there are six magnetic pole slots 101 extending along six sides of the same regular hexagon, so as to facilitate better distribution of air gap flux density. Preferably, the rotor core 100 is formed by laminating a plurality of electromagnetic steel sheets with a thickness of 0.3mm, so that the eddy current loss is small. For example, the rotor core 100 is provided with six rivet holes 102 equidistantly distributed on the same circumference, and the six rivet holes 102 and the six magnetic pole slots 101 respectively take the center of the rotor core 100 as the center of symmetry, and each rivet hole An imaginary line connecting the center of 102 and the center of the rotor core 100 passes through the center between adjacent magnetic pole slots 101 , and the rivets pass through the rivet holes 102 to fix a plurality of electromagnetic steel plates together.

According to some embodiments of the present invention, as shown in FIGS. 1 and 2 , at least one of the connecting sections 130 is straight. In other words, the d-axis arc segment 110 , at least one linear connecting segment 132 , at least one arc-shaped connecting segment 131 whose center is located outside the rotor core 100 and the q-axis arc segment 120 are circularly connected to form the rotor core 100 The outer contour of the rotor core 100 is thus further simplified to facilitate production and processing.

The rotor core 100 according to a specific embodiment of the present invention will be described in detail below with reference to FIG. 1 and FIGS. 3-5 . It should be understood that the following description is only an example and should not be construed as a limitation of the present invention.

As shown in Figure 1, according to the rotor core 100 of the embodiment of the present invention, the rotor core 100 is provided with six closed magnetic pole slots 101, and the six magnetic pole slots 101 are distributed along the circumferential direction of the rotor core 100 and respectively Extending along the six sides of the same regular hexagon, the rotor core 100 is provided with six rivet holes 102 equally spaced on the same circumference. The center of is the center of symmetry, and the outer contour of the rotor core 100 is composed of six line segments of the same shape with the center of the rotor core 100 as the center of symmetry.

Specifically, the outer contour of the rotor core 100 is composed of a d-axis circular arc section 110 connected in sequence, a straight line connecting section 132, a circular arc connecting section 131 whose center is located inside the rotor iron core 100, and a circle center located at the rotor core 100. The arc-shaped connecting section 131 on the outer side of 100 is formed by the q-axis arc section 120 , and the outer contour of the rotor core 100 is symmetrical with respect to the corresponding d-axis at the part between adjacent q-axes. Wherein, Rd=26.75mm, Rq=26.35mm, α=30°, α1=9°, the inner circle center of the rotor core 100 is located on the corresponding d-axis and 5.15mm away from the center of the rotor core 100 .

According to the rotor core 100 of the embodiment of the present utility model, Rq/Rd=0.985, α1/α=0.3. The rotor core 100 with this structure can not only optimize the distribution of the air-gap flux density of the motor, make the motor have a lower harmonic content of the air-gap flux density, reduce the electromagnetic excitation of the motor, but also have a simple structure, which is convenient for manufacturing and production ; At the same time, larger direct-axis inductance and quadrature-axis inductance can be realized, and the performance of the motor under weak magnetic field is good. Wherein, Fig. 4 is the distribution waveform of the air-gap magnetic density of the rotor core 100 according to the embodiment of the present utility model, and the waveform of the radial component of the air-gap magnetic density is close to a sinusoidal shape; The harmonic content of each order and the total content are obtained by decomposing the waveform of the radial component of the magnetic density.

The rotor core 100 according to an alternative embodiment of the present invention will be described in detail below with reference to FIG. 2 . It should be understood that the following description is only an example and should not be construed as a limitation of the present invention.

As shown in FIG. 2 , the structure of the rotor core 100 according to the embodiment of the present invention can refer to the rotor core 100 according to the above-mentioned specific embodiment of the present invention. In particular, in this embodiment, the outer contour of the rotor core 100 is composed of a d-axis circular arc section 110, a straight line connecting section 132, a circular arc connecting section 131 whose center is located inside the rotor core 100, The arc-shaped connecting section 131 whose center is located outside the rotor core 100, the arc-shaped connecting section 131 whose center is located inside the rotor core 100, the arc-shaped connecting section 131 whose center is located outside the rotor core 100, and the q-axis arc section 120, wherein the two arc-shaped connecting sections 131 whose centers are located outside the rotor core 100 have equal radii, and the two arc-shaped connecting sections 131 whose centers are located inside the rotor core 100 are located on the same circumference, The centers of the two arc-shaped connecting segments 131 whose centers are located inside the rotor core 100 are located on the corresponding d-axis and are 5.15 mm away from the center of the rotor core 100 . According to the rotor core 100 of the embodiment of the present utility model, α1=7°, that is, α1/α=0.233.

The rotor core 100 according to the embodiment of the utility model can not only optimize the distribution of the air-gap magnetic density and reduce the harmonic content of the air-gap magnetic density, but also has a simple structure, which is convenient for manufacturing and production; at the same time, it can improve the performance of the motor under weak magnetic field. performance.

As shown in Figures 1-5, the rotor 10 according to the embodiment of the second aspect of the utility model includes the rotor core 100 and a plurality of permanent magnets 200 according to the embodiment of the first aspect of the utility model, and the plurality of permanent magnets 200 are installed in a plurality of magnetic pole slots 101 respectively. Preferably, the permanent magnet 200 is a rare earth permanent magnet with a remanence greater than 1.25T and a coercive force greater than 900kA/m.

According to the rotor 10 of the embodiment of the present invention, by using the rotor core 100 as described above, not only can the motor have lower air-gap flux density harmonic content, but also the structure is simple, easy to manufacture and produce, and the yield is high. In addition, the rotor 10 can increase the direct-axis inductance value and the quadrature-axis inductance value of the motor, and improve the performance of the motor running under a magnetic field weakening condition.

As shown in Figures 1-5, the motor 1 according to the embodiment of the third aspect of the utility model includes the rotor 10 according to the embodiment of the second aspect of the utility model. Among them, the motor 1 is a permanent magnet embedded motor.

According to the motor 1 of the embodiment of the present invention, using the above-mentioned rotor 10, the distribution of the air-gap magnetic density is better, and the harmonic content of the air-gap magnetic density is less, so that the electromagnetic excitation is relatively small, the vibration and noise are small, and the structure Simple, easy to manufacture and produce. In addition, the direct-axis inductance and the quadrature-axis inductance of the motor 1 are relatively large, and the performance is good under the condition of field weakening.

Other configurations and operations of the stator 20 of the motor 1 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

The compressor according to the embodiment of the fourth aspect of the utility model includes the motor 1 according to the embodiment of the third aspect of the utility model, and the compressor is an inverter compressor.

According to the compressor of the embodiment of the present utility model, the motor 1 as described above is used, and the vibration and noise are small and the energy efficiency is high.

In the description of the present invention, it should be understood that the terms "center", "width", "thickness", "upper", "lower", "inner", "outer", "radial", "circumferential The orientation or positional relationship indicated by ", etc. is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, so as to Specific orientation configurations and operations, therefore, should not be construed as limitations on the invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present utility model, unless otherwise specified, "plurality" means two or more.

In the description of the present utility model, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a flexible connection. Detachable connection, or integral connection; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific examples" or "some examples" etc. Specific features, structures, materials, or characteristics described in or examples are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications, the scope of the present invention is defined by the claims and their equivalents.

Claims (14)

1. A rotor core, characterized in that the rotor core is provided with a plurality of magnetic pole slots arranged at intervals along the circumference of the rotor core, on a plane perpendicular to the central axis of the rotor core Inside, the outer profile of the rotor core includes: d-axis arc segment, the center of the d-axis arc segment coincides with the center of the rotor core and the d-axis of the rotor core passes through the center of the d-axis arc segment; A q-axis arc segment, the center of the q-axis arc segment coincides with the center of the rotor core and the q-axis of the rotor core passes through the center of the q-axis arc segment; Several connecting sections, the several connecting sections are connected between the adjacent d-axis circular arc sections and the q-axis circular arc sections, at least one of the several connecting sections is a circle whose center is located outside the rotor core arcuate and disposed adjacent to the q-axis, Wherein, the radius of the d-axis arc segment is Rd, the radius of the q-axis arc segment is Rq, and 0.9<Rq/Rd≤1. 2. The rotor core according to claim 1, characterized in that, the included angle between the adjacent d-axis and the q-axis is α, and the distance from the q-axis in the arc-shaped connecting section is The angle between the imaginary line connecting the center of the nearest one of the axes and the center of the rotor core and the q-axis is α1, 0.16≦α1/α<0.45. 3. The rotor core according to claim 1, wherein the area enclosed by the outer contour of the rotor core is S1, and the area of the circle where the d-axis arc segment is located is S2, 0.95 <S1/S2<0.99. 4 . The rotor core according to claim 1 , wherein the minimum distance between adjacent magnetic pole slots is less than 1 mm. 5 . The rotor core according to claim 1 , wherein a non-punching area is formed between the magnetic pole slots and the outer contour of the rotor core. 6. The rotor core according to claim 1, characterized in that the minimum distance between the magnetic pole slots and the outer contour of the rotor core is less than 0.8mm. 7. The rotor core according to claim 1, wherein the distance between the center of the magnetic pole slot and the center of the rotor core is greater than 0.8Rd and less than Rq. 8 . The rotor core according to claim 1 , wherein there are six magnetic pole slots extending along six sides of the same regular hexagon. 9 . The rotor core according to claim 1 , wherein the rotor core is formed by laminating a plurality of electromagnetic steel plates with a thickness of 0.3 mm. 10 . The rotor core according to claim 1 , wherein at least one of the connecting sections is straight. 11 . 11. A rotor, characterized in that it comprises: A rotor core according to any one of claims 1-10; A plurality of permanent magnets, the plurality of permanent magnets are respectively installed in the plurality of magnetic pole slots. 12 . The rotor according to claim 11 , wherein the permanent magnet is a rare earth permanent magnet with a remanence greater than 1.25T and a coercive force greater than 900kA/m. 13. An electrical machine, characterized by comprising the rotor according to claim 11 or 12. 14. A compressor, characterized by comprising the motor according to claim 13.