Motor rotor, permanent magnet motor and compressor

Abstract

The invention provides a motor rotor, a permanent magnet motor and a compressor, outer side magnetic pole parts are formed between the outer side inner wall of a first accommodating groove of the motor rotor and the side wall of a corresponding rotor iron core, each outer side magnetic pole part is provided with a plurality of first slits, the plurality of first slits enable two end faces of the motor rotor to be conducted respectively, on the section, perpendicular to the rotating shaft, of the outer side magnetic pole part, the end point of one end of each first slit is connected with the end point of the other end of the first slit to form a first slit direction line, a slit included angle is formed between any two of the slit direction lines, and at least one slit included angle is larger than or equal to 60 degrees. According to the technical scheme, the air-gap flux density sine degree is high, so that the energy conduction efficiency of an air-gap magnetic field is high, the torque of the tooth groove is reduced in the no-load state, the torque fluctuation is small in the load state, the tangential vibration of the compressor can be reduced, and then the noise of the compressor is reduced.

Description

[0001] This application is a divisional application of the Chinese patent application with the application date of July 27, 2017, application number "201710626224.7", and invention name "Motor Rotor, Permanent Magnet Motor and Compressor". Technical Field

[0002] The present invention relates to the field of compressors, and in particular to a motor rotor, a permanent magnet motor and a compressor. Background Art

[0003] In the related technology, the motor inverter is mainly used for the variable frequency speed regulation of the AC motor. The inverter mainly adopts the AC-DC-AC scheme. The industrial frequency power supply of the power grid is converted into a fixed DC voltage through a rectifier, and then the SPWM high-frequency converter composed of MOSFET or IGBT inverts the DC voltage into an AC output with variable voltage and frequency and a waveform close to a sine wave, which is used to drive the AC asynchronous motor to achieve stepless speed regulation. Due to the existence of the DC link, a large-capacity electrolytic capacitor is required to filter the rectified voltage into a smooth DC voltage. The electrolytic capacitor has the defects of short life at high temperature, large loss and possible explosion, and high cost.

[0004] The matrix AC-AC inverter without electrolytic capacitors belongs to the motor power supply. By utilizing a bidirectional switch, the three-phase input AC voltage is chopped into pieces at every moment, and then assembled into three-phase AC power of another frequency at the output end as needed to supply the motor operation. The permanent magnet motor of the compressor driven by the inverter without electrolytic capacitor has higher requirements on the tangential indicators such as the torque fluctuation of the permanent magnet motor. Summary of the invention

[0005] In order to solve at least one of the above technical problems, an object of the present invention is to provide a motor rotor.

[0006] Another object of the present invention is to provide a permanent magnet motor.

[0007] Another object of the present invention is to provide a compressor.

[0008] In order to achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes a motor rotor, which is arranged in cooperation with a motor stator. The motor stator is connected to a variable frequency drive to be driven to rotate by the variable frequency drive. The variable frequency drive does not have an electrolytic capacitor. The motor rotor includes a rotor core. A plurality of first accommodating grooves are provided on the rotor core along the axial direction of the rotating shaft. The plurality of first accommodating grooves are distributed along the circumferential direction. The first accommodating grooves are filled with permanent magnets. An outer magnetic pole portion is formed between the outer inner wall of the first accommodating groove and the corresponding side wall of the rotor core. A plurality of first slits are provided on each outer magnetic pole portion. The plurality of first slits respectively connect the two end faces of the motor rotor. In the cross section of the outer magnetic pole portion perpendicular to the rotating shaft, the endpoints of one end of each first slit are connected to the endpoints of the other end to form a slit direction line. There is a slit angle between any two of the plurality of slit direction lines, and at least one slit angle is greater than or equal to 60°.

[0009] In this technical solution, multiple first accommodating grooves are circumferentially arranged to fill the permanent magnets, thereby forming an outer magnetic pole portion and an inner magnetic pole portion on both sides of the permanent magnet, respectively. In the area of ​​the outer magnetic pole portion, multiple first slits are opened along the axial direction, and the two end faces of the motor rotor are made conductive. In the end face of an outer magnetic pole portion or the cross-section (or end face) area perpendicular to the rotation axis, the line between the two end points of the first slit is determined as the first slit direction line, and there is a slit angle between any two of the multiple slit direction lines, and at least one slit angle is greater than or equal to 60°. In the process of being driven to rotate by a variable frequency drive without an electrolytic capacitor, since at least two first slits with a specified angle are arranged, the air gap magnetic density has a high sinusoidality, and thus the energy conduction efficiency of the air gap magnetic field is high. When idling, the torque of the tooth slot is reduced, and when loaded, the torque fluctuation is small, thereby reducing the tangential vibration of the compressor and further reducing the noise of the compressor.

[0010] There is a slit angle between any two of the plurality of slit direction lines, that is, the slit angle can be formed by two adjacent slit direction lines or by two non-adjacent slit direction lines.

[0011] There is an air gap between the stator and rotor of the motor. After the motor stator and the frequency converter are turned on, a magnetic field is formed in the air gap. The strength of the magnetic field is called air gap flux density. In the permanent magnet motor system, due to the interaction between the permanent magnet and the slotted armature core, cogging torque is inevitably generated, resulting in torque fluctuation, vibration and noise, and affecting the control accuracy of the system. The motor can adopt the "sine wave" principle in its body structure. Even if the air gap magnetic field generated by the motor rotor is distributed as a sine wave, a sinusoidal commutation function is used, which can greatly reduce torque fluctuation. The reduction of torque fluctuation not only improves the accuracy of the motor, but also reduces the starting voltage.

[0012] Specifically, a compressor equipped with a rotor is driven by an inverter with no electrolytic capacitors. The rotor consists of a rotor core, permanent magnet slots and permanent magnets arranged in the permanent magnet slots. At least two first slits are arranged on the radially outer side corresponding to each permanent magnet slot, that is, the outer magnetic pole portion. By connecting one end of each first slit to the other end, and defining the connecting line as a first slit direction line, on the same outer magnetic pole portion, there is a slit angle between any two of the multiple slit direction lines, and at least one slit angle α is ≥60°.

[0013] As a preferred arrangement, the permanent magnets are arranged circumferentially symmetrically with respect to the center of the rotation axis, so that the corresponding outer magnetic poles are also arranged circumferentially symmetrically with respect to the center of the rotation axis.

[0014] In addition, the motor rotor in the above embodiment provided by the present invention may also have the following additional technical features:

[0015] In the above technical solution, preferably, on each cross section, the axis of the rotating shaft is connected to the center of the permanent magnet to form a first axis, and two adjacent first slits are symmetrically arranged relative to the first axis.

[0016] In this technical solution, on the cross-section of each outer magnetic pole portion, a first connecting line is formed between the end points of two adjacent first slits, the midpoint of the first connecting line is connected to the axis center of the rotating shaft to form a first axis, and the two first slits are arranged to be symmetrical relative to the first axis. During the rotation of the rotor, the negative effects of the two first slits can offset each other, further improving the sinusoidal degree of the air gap magnetic density.

[0017] In any of the above technical solutions, preferably, on each cross section, there is a second line between any point on the permanent magnet and the axis, and the second line extends outward to have a first intersection with the side wall; there is a circumferential gap area between two adjacent permanent magnets, and any point in the circumferential gap area is connected with the axis to form a third line, and the third line extends outward to have a second intersection with the side wall, wherein the distance between the axis and the first intersection is greater than the distance between the axis and the second intersection.

[0018] In this technical solution, on each cross section or on the end faces at both ends, there is a second connecting line between any point on the permanent magnet and the axis, the second connecting line extends outward and has a first intersection with the side wall, a circumferential gap area is provided between two adjacent permanent magnets, any point in the circumferential gap area is connected with the axis to form a third connecting line, the third connecting line extends outward and has a second intersection with the side wall, the distance between the axis and the first intersection is greater than the distance between the axis and the second intersection, that is, the distance from the axis to any point on the first outer wall contour line corresponding to the permanent magnet is greater than the distance from the axis to any point on the second outer wall contour line corresponding to both sides of the permanent magnet, thereby forming an unequal air gap between the outer wall of the rotor and the inner wall of the matching stator, thereby optimizing the air gap magnetic resistance distribution, and further improving the sinusoidality of the air gap magnetic density on the basis of limiting the first slit direction line angle, thereby reducing the back electromotive force harmonic distortion rate and starting resistance torque.

[0019] Specifically, the line passing through the axis center and the permanent magnet can be set as the d-axis, and the line passing through the axis center and the adjacent permanent magnet can be set as the q-axis. The distance between the axis center and the outer wall on the d-axis is L1, which is greater than the distance between the axis center and the outer wall on the q-axis is L2, that is, the outer periphery of the motor rotor adopts a non-cylindrical structure.

[0020] In any of the above technical solutions, preferably, the side wall of the rotor core is formed by a plurality of curved grooves arranged at intervals in the circumferential direction on the cylindrical surface, and each curved groove is arranged corresponding to the third connecting line one by one.

[0021] In this technical solution, by constructing the side wall of the rotor core to have multiple curved grooves spaced circumferentially on the cylindrical surface, on the one hand, the preparation method is relatively simple, and on the other hand, it can also satisfy the requirement that the distance from the axis to any point on the first outer wall contour line corresponding to the permanent magnet is greater than the distance from the axis to any point on the second outer wall contour line corresponding to both sides of the permanent magnet, so as to achieve the best effect in optimizing the sinusoidality of the air gap magnetic density.

[0022] In addition, the side wall profile of the rotor core can also be constructed to be formed by a plurality of inwardly opening arcs symmetrically distributed along the axis, and straight lines symmetrically arranged on both sides of the arcs, with an end-to-end connection structure, so that the gap between the outer wall of the motor rotor and the inner wall of the matching motor stator approaches a sinusoidal distribution.

[0023] In any of the above technical solutions, preferably, the side wall of the rotor core is configured as a cylindrical structure.

[0024] In this technical solution, by constructing the side wall of the rotor core into a cylindrical structure, on the one hand, it can meet the use requirements of being driven by a frequency converter without an electrolytic capacitor. On the other hand, compared with further processing the outer side wall of the motor rotor to obtain a different air gap solution, the preparation cost is lower.

[0025] In any of the above technical solutions, preferably, the first slit and the corresponding first receiving groove are relatively spaced apart from each other.

[0026] In this technical solution, by relatively separating the first slit and the corresponding first containing groove, the difficulty of preparing the first slit can be reduced while satisfying the requirement of optimizing the air gap magnetic density.

[0027] In any of the above technical solutions, preferably, the first slit extends inwardly along the first slit direction line to the corresponding first receiving groove to be connected with the corresponding first receiving groove.

[0028] In this technical solution, by extending the first slit inwardly along the first slit direction line to the corresponding first accommodating groove so as to be connected with the corresponding first accommodating groove, it is beneficial to further reduce torque fluctuations during the rotation of the rotor.

[0029] In any of the above technical solutions, preferably, both ends of the first accommodating groove extend outward respectively to form symmetrical second accommodating grooves; the motor rotor also includes: symmetrically arranged second slits, which are opened on the outer magnetic pole portion and are respectively connected to the corresponding second accommodating grooves, wherein, in the cross section, the endpoint of one end of each second slit is connected to the endpoint of the other end to form a second slit direction line, and the angle between two adjacent second slit direction lines is greater than or equal to 60°.

[0030] In this technical solution, the second slits are symmetrically arranged, and the angle between the direction lines of two adjacent second slits is greater than or equal to 60°, thereby further improving the sinusoidality of the air gap magnetic flux density.

[0031] In any of the above technical solutions, preferably, the contour line of the first slit is formed by connecting a plurality of straight lines and / or curves end to end.

[0032] Specifically, the first slit may be an oblique rectangular first slit, or an arcuate first slit, or a combination of a rectangular first slit and an arcuate first slit, a combination of a rectangular first slit and a rectangular first slit, or a combination of an arcuate first slit and an arcuate first slit.

[0033] In any of the above technical solutions, preferably, both ends of each first accommodating groove extend outwards respectively to form a second accommodating groove, and the second accommodating groove is filled with magnetic isolation material.

[0034] In this technical solution, by filling the second receiving groove with magnetic isolation material, the interference between two adjacent permanent magnets can be reduced.

[0035] The embodiment of the second aspect of the present invention proposes a permanent magnet motor, comprising: a motor stator connected to a variable frequency drive, the variable frequency drive does not have an electrolytic capacitor; and a motor rotor as described in the embodiment of the first aspect of the present invention, assembled in conjunction with the motor stator.

[0036] An embodiment of the third aspect of the present invention provides a compressor, comprising the permanent magnet motor described in the embodiment of the second aspect of the present invention.

[0037] Specifically, the compressor according to the embodiment of the present invention further includes compression components such as a cylinder, a main bearing, a secondary bearing, a piston and a crankshaft.

[0038] Additional aspects and advantages of the present invention will become apparent in the following description or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0040] Figure 1 A schematic diagram of the structure of a motor rotor according to an embodiment of the present invention is shown;

[0041] Figure 2 Shows Figure 1 Schematic diagram of the local structure of the motor rotor;

[0042] Figure 3 A partial structural schematic diagram of a motor rotor according to another embodiment of the present invention is shown;

[0043] Figure 4 A partial structural schematic diagram of a motor rotor according to another embodiment of the present invention is shown;

[0044] Figure 5 A partial structural schematic diagram of a motor rotor according to another embodiment of the present invention is shown;

[0045] Figure 6 A schematic structural diagram of a permanent magnet motor according to an embodiment of the present invention is shown;

[0046] Figure 7 Shows the loading Figure 1 A schematic diagram comparing the load torque curves of the permanent magnet motor with a middle rotor and the permanent magnet motor in the related art;

[0047] Figure 8 A schematic structural diagram of a compressor according to an embodiment of the present invention is shown.

[0048] in, Figures 1 to 6 as well as Figure 8The corresponding relationship between the reference numerals and the component names is as follows:

[0049] 10 motor rotor, 102 rotor core, 104 permanent magnet, 106 first slit, 108 second receiving groove, 110 second slit, 20 motor stator, 202 stator core, 204 winding, 30 cylinder, 40 main bearing, 50 secondary bearing, 60 piston, 70 crankshaft. DETAILED DESCRIPTION

[0050] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0051] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0052] Refer to the following Figures 1 to 8 A rotor for an electric machine according to some embodiments of the invention is described.

[0053] Embodiment 1:

[0054] like Figure 1 As shown, according to an embodiment of the present invention, the motor rotor 10 is arranged in cooperation with the motor stator 20, and the motor stator 20 is connected to a variable frequency drive to be driven to rotate by the variable frequency drive. The variable frequency drive does not have an electrolytic capacitor. The motor rotor 10 includes a rotor core 102. A plurality of first accommodating grooves are provided on the rotor core 102 along the axial direction of the rotating shaft. The plurality of first accommodating grooves are distributed along the circumferential direction. The first accommodating grooves are filled with permanent magnets 104. An outer magnetic pole portion is formed between the outer inner wall of the first accommodating groove and the corresponding side wall of the rotor core 102. A plurality of first slits 106 are provided on each outer magnetic pole portion. The plurality of first slits 106 respectively connect the two end faces of the motor rotor 10, wherein, on a cross section of the outer magnetic pole portion perpendicular to the rotating shaft, an end point of one end of each first slit 106 is connected to an end point of the other end to form a slit direction line, and a slit angle is provided between any two of the plurality of slit direction lines, and at least one slit angle α is ≥ 60°.

[0055] In this embodiment, multiple first accommodating grooves are circumferentially arranged to fill the permanent magnet 104, so that an outer magnetic pole portion and an inner magnetic pole portion are formed on both sides of the permanent magnet 104, respectively. In the area of ​​the outer magnetic pole portion, multiple first slits 106 are axially opened, and the two end faces of the motor rotor 10 are connected. At the end face of an outer magnetic pole portion or the cross-section (or end face) area perpendicular to the rotation axis, the line between the two end points of the first slit 106 is determined as the first slit direction line, and there is a slit angle between any two of the multiple slit direction lines, and at least one slit angle is greater than or equal to 60°. In the process of being driven to rotate by a variable frequency drive without an electrolytic capacitor, since at least two first slits 106 with a specified angle are arranged, the air gap magnetic density has a high sinusoidality, and thus the energy conduction efficiency of the air gap magnetic field is high. When idling, the torque of the tooth slot is reduced, and when loaded, the torque fluctuation is small, thereby reducing the tangential vibration of the compressor and further reducing the noise of the compressor.

[0056] There is a slit angle between any two of the plurality of slit direction lines, that is, the slit angle can be formed by two adjacent slit direction lines or by two non-adjacent slit direction lines.

[0057] There is an air gap between the stator and the rotor of the motor. After the motor stator 20 is connected to the frequency converter, a magnetic field is formed in the air gap. The strength of the magnetic field is called air gap flux density. In the permanent magnet motor system, due to the interaction between the permanent magnet 104 and the slotted armature core, cogging torque is inevitably generated, resulting in torque fluctuations, causing vibration and noise, and affecting the control accuracy of the system. The motor can adopt the "sine wave" principle in its main structure. Even if the air gap magnetic field generated by the motor rotor 10 is distributed as a sine wave, a sinusoidal commutation function is used, which can greatly reduce the torque fluctuation. The reduction in torque fluctuation not only improves the accuracy of the motor, but also reduces the starting voltage.

[0058] Specifically, the compressor equipped with the rotor is driven by an inverter with no electrolytic capacitors. The rotor is composed of a rotor core 102, permanent magnet slots and permanent magnets 104 arranged in the permanent magnet slots. At least two first slits 106 are arranged on the radially outer side corresponding to each permanent magnet slot, that is, the outer magnetic pole portion. By connecting one end of each first slit 106 to the other end, and defining the connecting line as a first slit direction line, on the same outer magnetic pole portion, there is a slit angle between any two of the multiple slit direction lines, and at least one slit angle α is ≥60°.

[0059] Embodiment 2:

[0060] As a preferred arrangement, the permanent magnets 104 are arranged circumferentially symmetrically with respect to the center of the rotation axis, so that the corresponding outer magnetic pole portions are also arranged circumferentially symmetrically with respect to the center of the rotation axis.

[0061] In addition, the motor rotor 10 in the above embodiment provided by the present invention may also have the following additional technical features:

[0062] Embodiment three:

[0063] In the above embodiment, preferably, on each cross section, a first connecting line is formed between the endpoints of two adjacent first slits 106 , the midpoint of the first connecting line is connected to the axis of the rotation axis to form a first axis, and the two first slits 106 are symmetrically arranged relative to the first axis.

[0064] In this embodiment, on the cross section of each outer magnetic pole portion, a first connecting line is formed between the endpoints of two adjacent first slits 106, and the midpoint of the first connecting line is connected to the axis center of the rotating shaft to form a first axis. The two first slits 106 are arranged to be symmetrical relative to the first axis. During the rotation of the rotor, the negative effects of the two first slits 106 can offset each other, thereby further improving the sinusoidality of the air gap magnetic density.

[0065] Embodiment 4:

[0066] like Figure 2 As shown, in any of the above embodiments, preferably, on each cross section, there is a second line between any point on the permanent magnet 104 and the axis, and the second line extends outward to have a first intersection with the side wall; there is a circumferential gap area between two adjacent permanent magnets 104, and any point in the circumferential gap area is connected with the axis to form a third line, and the third line extends outward to have a second intersection with the side wall, wherein the distance between the axis and the first intersection is greater than the distance between the axis and the second intersection.

[0067] In this embodiment, on each cross section or on the end faces at both ends, there is a second connecting line between any point on the permanent magnet 104 and the axis, the second connecting line extends outwardly and has a first intersection with the side wall, a circumferential gap area is provided between two adjacent permanent magnets 104, any point in the circumferential gap area is connected with the axis to form a third connecting line, the third connecting line extends outwardly and has a second intersection with the side wall, the distance between the axis and the first intersection is greater than the distance between the axis and the second intersection, that is, the distance from the axis to any point on the first outer wall contour line corresponding to the permanent magnet 104 is greater than the distance from the axis to any point on the second outer wall contour line corresponding to both sides of the permanent magnet 104, thereby forming unequal air gaps between the outer wall of the rotor and the inner wall of the matching stator, thereby optimizing the air gap magnetic resistance distribution, and further improving the sinusoidality of the air gap magnetic density on the basis of limiting the first slit direction line angle, thereby reducing the back electromotive force harmonic distortion rate and starting resistance torque.

[0068] Specifically, the line passing through the axis center and the permanent magnet 104 can be set as the d-axis, and the line passing through the axis center and the adjacent permanent magnet 104 can be set as the q-axis. The distance between the axis center and the outer wall on the d-axis is L1, which is greater than the distance between the axis center and the outer wall on the q-axis L2, that is, the outer periphery of the motor rotor 10 adopts a non-cylindrical structure.

[0069] Embodiment five:

[0070] like Figure 2 As shown, in any of the above embodiments, preferably, the side wall of the rotor core 102 is formed by a plurality of curved grooves arranged circumferentially at intervals on the cylindrical surface, and each curved groove is arranged one by one corresponding to the third connecting line.

[0071] In this embodiment, by constructing the side wall of the rotor core 102 to have a plurality of curved grooves spaced circumferentially on the cylindrical surface, on the one hand, the preparation method is relatively simple, and on the other hand, it can also satisfy the requirement that the distance from the axis to any point on the first outer wall contour line corresponding to the permanent magnet 104 is greater than the distance from the axis to any point on the second outer wall contour line corresponding to both sides of the permanent magnet 104, so as to achieve the best effect in optimizing the sinusoidality of the air gap magnetic flux.

[0072] Embodiment six:

[0073] In addition, the side wall profile of the rotor core 102 can also be constructed to be formed by a plurality of inwardly opening arcs symmetrically distributed along the axis, and straight lines symmetrically arranged on both sides of the arcs, with an end-to-end connection structure, so that the gap between the outer wall of the motor rotor 10 and the inner wall of the matching motor stator 20 approaches a sinusoidal distribution.

[0074] Embodiment seven:

[0075] like Figure 3 As shown, in any of the above embodiments, preferably, the side wall of the rotor core 102 is configured as a cylindrical structure.

[0076] In this embodiment, by constructing the side wall of the rotor core 102 into a cylindrical structure, on the one hand, it can meet the use requirements of being driven by a frequency converter without an electrolytic capacitor. On the other hand, compared with further processing the outer wall of the motor rotor 10 to obtain a different air gap solution, the preparation cost is lower.

[0077] Embodiment eight:

[0078] In any of the above embodiments, preferably, the first slit 106 and the corresponding first receiving groove are relatively spaced apart from each other.

[0079] In this embodiment, by relatively separating the first slit 106 and the corresponding first receiving groove, the difficulty of preparing the first slit 106 can be reduced while satisfying the requirement of optimizing the air gap magnetic density.

[0080] Embodiment nine:

[0081] In any of the above embodiments, preferably, the first slit 106 extends inwardly along the first slit direction line to the corresponding first receiving groove to be connected with the corresponding first receiving groove.

[0082] In this embodiment, by extending the first slit 106 inwardly along the first slit direction line to the corresponding first receiving groove so as to be connected with the corresponding first receiving groove, it is helpful to further reduce torque fluctuation during the rotation of the rotor.

[0083] Embodiment ten:

[0084] like Figure 4 As shown, in any of the above embodiments, preferably, both ends of the first accommodating groove extend outward respectively to form symmetrical second accommodating grooves 108; the motor rotor 10 also includes: symmetrically arranged second slits 110, which are opened on the outer magnetic pole portion and are respectively connected to the corresponding second accommodating grooves 108, wherein, in the cross section, the endpoints of one end of each second slit 110 are connected to the endpoints of the other end to form a second slit direction line, and the angle between two adjacent second slit direction lines is greater than or equal to 60°.

[0085] In this embodiment, the second slits 110 are symmetrically arranged, and the angle between two adjacent second slit direction lines is greater than or equal to 60°, thereby further improving the sinusoidality of the air gap magnetic flux density.

[0086] like Figure 5 As shown, in any of the above embodiments, preferably, the contour line of the first slit 106 is formed by connecting a plurality of straight lines and / or curves end to end.

[0087] Specifically, the first slit 106 may be an oblique rectangular first slit, or an arcuate first slit, or a combination of a rectangular first slit and an arcuate first slit, a combination of a rectangular first slit and a rectangular first slit, or a combination of an arcuate first slit and an arcuate first slit.

[0088] In addition, the second slit 110 may be an oblique rectangular second slit, or an arcuate second slit, or a combination of a rectangular second slit and an arcuate second slit, a combination of a rectangular second slit and a rectangular second slit, or a combination of an arcuate second slit and an arcuate second slit.

[0089] In any of the above embodiments, preferably, both ends of each first receiving groove extend outwards respectively to form a second receiving groove 108 , and the second receiving groove 108 is filled with magnetic isolation material.

[0090] In this embodiment, by filling the second receiving groove 108 with magnetic isolation material, interference between two adjacent permanent magnets 104 can be reduced.

[0091] like Figure 6 As shown, the permanent magnet motor according to an embodiment of the present invention includes: a motor stator 20 connected to a variable frequency drive, the variable frequency drive does not have an electrolytic capacitor; and a motor rotor 10 as described in any of the above embodiments of the present invention, assembled in conjunction with the motor stator 20.

[0092] like Figure 6 As shown, the motor stator 20 includes a stator core 202 and a winding 204, and the winding is arranged in the slot of the stator core 202. By constructing the side wall profile of the rotor core 102 into a plurality of inwardly opening arcs symmetrically distributed along the axis, and straight lines or inwardly recessed arcs symmetrically arranged on both sides of the arc, a head-to-tail connection structure is formed, so that the gap between the outer wall of the motor rotor 10 and the inner wall of the matching motor stator 20 approaches a sinusoidal distribution, wherein the motor rotor 10 includes a rotor core 102, a permanent magnet 104 and a first slit 106.

[0093] like Figure 7 As shown, a schematic diagram of a load torque curve using the motor rotor in Example 1 compared with related technologies is shown. It is known from actual verification that the load torque fluctuation of the permanent magnet motor equipped with the motor rotor in Example 1 is significantly reduced compared with the permanent magnet motor without a limited slit, which is beneficial to reducing the tangential vibration of the compressor and reducing the compressor noise.

[0094] like Figure 8 As shown, a compressor according to an embodiment of the present invention includes the permanent magnet motor described in the above embodiment.

[0095] Specifically, the compressor according to the embodiment of the present invention further includes compression components such as a cylinder 30 , a main bearing 40 , a secondary bearing 50 , a piston 60 , and a crankshaft 70 .

[0096] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0097] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0098] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0099] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A motor rotor, arranged in cooperation with a motor stator, the motor stator being connected to a variable frequency drive to be driven to rotate by the variable frequency drive, the motor rotor comprising a rotor core, a plurality of first accommodating grooves being provided on the rotor core along the axial direction of the rotating shaft, the plurality of first accommodating grooves being distributed along the circumferential direction, the first accommodating grooves being filled with permanent magnets, characterized in that: An outer magnetic pole portion is formed between the outer inner wall of the first accommodating groove and the corresponding side wall of the rotor core, and a plurality of first slits are provided on each of the outer magnetic pole portions, and the plurality of first slits respectively connect the two end surfaces of the motor rotor. Wherein, on the cross section of the outer magnetic pole portion perpendicular to the rotation axis, an endpoint of one end of each of the first slits is connected to an endpoint of the other end to form a slit direction line, and a slit angle is formed between any two of the plurality of slit direction lines, and at least one of the slit angles is greater than or equal to 60°; On each of the cross sections, there is a second connecting line between any point on the permanent magnet and the axis of the rotating shaft, and the second connecting line extends outwards and has a first intersection with the side wall; There is a circumferential gap region between two adjacent permanent magnets, any point in the circumferential gap region is connected with the axis to form a third line, and the third line extends outward to have a second intersection with the side wall, Wherein, the distance between the axis and the first intersection is greater than the distance between the axis and the second intersection.

2. The motor rotor according to claim 1, characterized in that: In each of the cross sections, the axis of the rotating shaft is connected to the center of the permanent magnet to form a first axis, and two adjacent first slits are symmetrically arranged relative to the first axis.

3. The motor rotor according to claim 1, characterized in that: The side wall of the rotor core is formed by a plurality of curved grooves arranged at intervals in the circumferential direction on the cylindrical surface, and each of the curved grooves is arranged corresponding to the third connecting line one by one.

4. The motor rotor according to claim 1, characterized in that: The side wall of the rotor core is configured as a cylindrical structure.

5. The motor rotor according to claim 3 or 4, characterized in that: The first slit and the corresponding first containing groove are relatively spaced apart from each other.

6. The motor rotor according to claim 3 or 4, characterized in that: The first slit extends inwardly along a first slit direction line to the corresponding first receiving groove to be connected with the corresponding first receiving groove.

7. The motor rotor according to claim 3 or 4, characterized in that: Both ends of the first receiving groove extend outwards respectively to form a symmetrical second receiving groove; The motor rotor also includes: The symmetrically arranged second slits are opened on the outer magnetic pole portion and are respectively connected to the corresponding second accommodating grooves.

8. The motor rotor according to claim 7, characterized in that: On the cross section, an endpoint at one end of each second slit is connected to an endpoint at the other end to form a second slit direction line, and an angle between two adjacent second slit direction lines is greater than or equal to 60°.

9. The motor rotor according to any one of claims 1 to 4, characterized in that: The outline of the first slit is formed by connecting a plurality of straight lines and / or curves end to end.

10. The motor rotor according to any one of claims 1 to 4, characterized in that: The variable frequency drive has no electrolytic capacitors therein.

11. A permanent magnet motor, characterized in that: include: The motor stator is connected to the variable frequency drive; The motor rotor according to any one of claims 1 to 10 is assembled in cooperation with the motor stator.

12. A compressor, characterized in that: include: The permanent magnet motor as claimed in claim 11.

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