Permanent magnet synchronous motor rotor structure, motor and electric spindle

Abstract

The permanent magnet synchronous motor rotor structure comprises a magnetic conductive rotating shaft, a plurality of magnetic steel grooves are formed in the peripheral surface of the magnetic conductive rotating shaft, the magnetic steel grooves are distributed in the circumferential direction of the magnetic conductive rotating shaft, and permanent magnet magnetism gathering magnetic poles are arranged in the magnetic steel grooves. The permanent magnet magnetism gathering magnetic pole comprises a radial magnetic flux permanent magnet, a first tangential magnetic flux permanent magnet and a second tangential magnetic flux permanent magnet, and the first tangential magnetic flux permanent magnet and the second tangential magnetic flux permanent magnet are arranged on the two sides of the radial magnetic flux permanent magnet in the circumferential direction of the magnetic conductive rotating shaft. The magnetic flux directions of the first tangential magnetic flux permanent magnets and the second tangential magnetic flux permanent magnets are opposite, gaps are reserved between the adjacent magnetic steel grooves in the circumferential direction of the magnetic conductive rotating shaft, and soft magnetic adjustable magnetic poles are formed in the portions, between the adjacent magnetic steel grooves, of the magnetic conductive rotating shaft. The built-in induction motor for the electric spindle solves the problems that an existing built-in induction motor for the electric spindle is low in machining precision, low in efficiency, low in power density, large in motor size, low in control precision and slow in response time.

Description

Technical Field

[0001] The invention is used in the field of motors, and in particular relates to a permanent magnet synchronous motor rotor structure, a motor and an electric spindle. Background Art

[0002] Deep magnetic weakening speed regulation is the main development direction of turning and milling electric spindles to meet customers' needs for low-speed and high-torque roughing and high-speed and high-constant-power finishing. At present, the built-in asynchronous motor of the electric spindle still occupies the mainstream, but the following inherent characteristics of the asynchronous motor restrict its development:

[0003] 1. The rotor heats up seriously at low speed, and the resulting thermal elongation of the shaft will directly affect the machining accuracy of the machine tool;

[0004] 2. The rotor parameters change with temperature, which can easily cause control errors and affect the control accuracy of the motor;

[0005] 3. The power factor and efficiency are low, requiring a larger inverter capacity;

[0006] 4. The power (torque) density is low and the motor volume is large;

[0007] 5. Slow response time and long acceleration and deceleration time affect the machining efficiency of the machine tool.

[0008] Permanent magnet synchronous motor has a series of advantages such as simple structure, low loss, high power factor, high efficiency, and fast response speed, which naturally make up for the shortcomings of the above-mentioned induction motor. However, the magnetic field of the permanent magnet synchronous motor is generated by the permanent magnet and cannot be adjusted. The permanent magnet synchronous motor has the characteristic that the back electromotive force is basically proportional to the speed. When the input voltage reaches the limit voltage, due to the limitation of the inverter capacity, the motor winding can no longer input current. If you want to continue to increase the speed, you can only do it by adjusting the direct-axis component of the current and the quadrature-axis component of the current. By increasing the direct-axis component of the motor current and reducing the quadrature-axis component of the current, the voltage balance relationship is maintained. However, the current that the motor can withstand is limited. If the demagnetization current component is increased while ensuring that the armature current does not exceed the current limit value, the torque current will be reduced accordingly, so it is impossible to maintain constant power operation at high speed. Therefore, how to expand the weak magnetic speed regulation range of the permanent magnet synchronous motor has become a research hotspot for permanent magnet synchronous motors. In addition, it is well known that permanent magnet synchronous motors with certain weak magnetic speed regulation capabilities under existing technologies are all embedded rotor structures, but the laminated iron core rotor structure of the embedded rotor naturally restricts the maximum speed of such motors, while traditional surface-mounted rotor permanent magnet synchronous motors have basically no weak magnetic speed regulation capabilities. Summary of the invention

[0009] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a permanent magnet synchronous motor rotor structure, a motor and an electric spindle.

[0010] The technical solution adopted by the present invention to solve its technical problem is:

[0011] In a first aspect, a permanent magnet synchronous motor rotor structure comprises a magnetically conductive rotating shaft, wherein the outer circumferential surface of the magnetically conductive rotating shaft is provided with a plurality of magnetic steel slots, the plurality of magnetic steel slots are distributed along the circumference of the magnetically conductive rotating shaft, permanent magnet magnetic focusing poles are provided in the magnetic steel slots, the permanent magnet magnetic focusing poles comprise radial magnetic flux permanent magnets, first tangential magnetic flux permanent magnets and second tangential magnetic flux permanent magnets, the first tangential magnetic flux permanent magnets and the second tangential magnetic flux permanent magnets are arranged on both sides of the radial magnetic flux permanent magnets along the circumference of the magnetically conductive rotating shaft, the magnetic flux directions of the first tangential magnetic flux permanent magnets and the second tangential magnetic flux permanent magnets are opposite, a gap is left between adjacent magnetic steel slots along the circumference of the magnetically conductive rotating shaft, and the portion of the magnetically conductive rotating shaft between adjacent magnetic steel slots forms a soft magnetic tuning pole.

[0012] In combination with the first aspect, in certain implementations of the first aspect, the outer diameter of the soft magnetic tuning pole is the same as the outer diameter of the permanent magnet focusing pole, and the permanent magnet synchronous motor rotor structure also includes a protective cover, which is mounted on the outer circle of the soft magnetic tuning pole and the permanent magnet focusing pole.

[0013] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the protective cover comprises a carbon fiber protective cover, and the carbon fiber protective cover is interference fit on the outer circle of the soft magnetic tuning pole and the permanent magnet focusing pole.

[0014] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the outer circumferential surface of the magnetically conductive shaft is provided with two evenly distributed magnetic steel grooves, and the magnetically conductive shaft forms two soft magnetic tuning poles between the two magnetic steel grooves.

[0015] In combination with the first aspect and the above-mentioned implementation methods, in some implementation methods of the first aspect, the circumferential arc of each of the soft magnetic tuning poles is δ1, the circumferential arc of each of the radial flux permanent magnets is δ2, the circumferential arc of each of the first tangential flux permanent magnets is δ3, and the circumferential arc of each of the second tangential flux permanent magnets is δ4, and δ1+δ2+δ3+δ4=π.

[0016] In combination with the first aspect and the above implementations, in some implementations of the first aspect, δ1=δ2=δ3=δ4.

[0017] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the outer circumferential surface of the soft magnetic tuning pole is provided with annular shallow grooves equidistantly distributed along the axial direction.

[0018] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the radial flux permanent magnets, the first tangential flux permanent magnets, and the second tangential flux permanent magnets are equidistantly layered along the axial direction.

[0019] In a second aspect, a motor comprises a permanent magnet synchronous motor rotor structure as described in any implementation of the first aspect.

[0020] In a third aspect, an electric spindle comprises the motor described in any implementation of the second aspect.

[0021] One of the above technical solutions has at least one of the following advantages or beneficial effects: In the technical solution of the present invention, magnetic steel grooves are provided at intervals along the circumferential direction on the magnetic conductive shaft, and the magnetic steel grooves are used to arrange and place permanent magnet magnetic poles. By designing the arrangement of the permanent magnet magnetic poles, the rotor permanent magnet magnetic pole structure has a magnetic concentration effect. The permanent magnet magnetic poles are composed of tangential magnetic flux permanent magnets and radial magnetic flux permanent magnets, which will force the electromagnetic field lines in the motor not to enter the magnetic conductive shaft. On the one hand, the magnetic concentration effect improves the air gap magnetic field strength of the motor, enhances the magnetic field energy storage of the motor, and effectively improves the power density and torque density of the motor; on the other hand, the magnetic lines of force of the electromagnetic field in the motor are affected by the magnetic pole magnetic concentration effect, and most of the magnetic field does not enter the magnetic conductive shaft, which effectively suppresses the eddy current loss of the magnetic conductive shaft and greatly improves the heating problem on the rotor side.

[0022] At the same time, the spacing between the magnetic steel slots on the magnetic shaft not only plays a role in limiting the permanent magnet magnetic pole, but also acts as a soft magnetic magnetic pole for the motor. Under low-speed and high-torque operating conditions, the soft magnetic magnetic pole is magnetized into a working pole, and its polarity is opposite to that of the permanent magnet magnetic pole; under deep magnetic weakening operating conditions, the soft magnetic magnetic pole is weakly magnetized, and in addition to continuing to serve as a working pole, it also mainly provides a weak magnetic channel for the electromagnetic field in the motor. It is precisely because of the existence of the soft magnetic magnetic pole that this surface-mounted permanent magnet motor can truly achieve deep magnetic weakening.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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:

[0025] Figure 1 1 is a schematic diagram of the structure of an embodiment of the motor of the present invention;

[0026] Figure 2 yes Figure 1A schematic structural diagram of a permanent magnet synchronous motor rotor structure in one embodiment shown;

[0027] Figure 3 yes Figure 2 A schematic diagram of the circumferential arc of the permanent magnet magnetic concentrating pole and the soft magnetic tuning pole of the embodiment shown;

[0028] Figure 4 yes Figure 2 The end surface structure schematic diagram of the embodiment shown;

[0029] Figure 5 yes Figure 4 Cross-section at AA;

[0030] Figure 6 yes Figure 5 The partial enlarged picture of point Ⅰ in the middle;

[0031] Figure 7 yes Figure 5 A partial enlarged view of point II in the middle. DETAILED DESCRIPTION

[0032] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0033] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0034] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0036] See also Figure 1 , Figure 2 An embodiment of the present invention provides a motor, including a stator core 100 and a permanent magnet synchronous motor rotor structure, wherein the permanent magnet synchronous motor rotor structure includes a magnetically conductive rotating shaft 200, and a plurality of magnetic steel slots 201 are provided on the outer circumferential surface of the magnetically conductive rotating shaft 200, and the plurality of magnetic steel slots 201 are distributed along the circumferential direction of the magnetically conductive rotating shaft 200, and permanent magnet magnetic poles 202 are provided in the magnetic steel slots 201, and the permanent magnet magnetic poles 202 are arranged in the magnetic steel slots 201 by bonding and other processes to form a surface-mounted rotor permanent magnet synchronous motor. The permanent magnet magnetic pole 202 includes a radial flux permanent magnet 203, a first tangential flux permanent magnet 204 and a second tangential flux permanent magnet 205. The first tangential flux permanent magnet 204 and the second tangential flux permanent magnet 205 are arranged on both sides of the radial flux permanent magnet 203 along the circumference of the magnetic conductive shaft 200, wherein the magnetic flux direction of the radial flux permanent magnet 203 is arranged radially, for example, Figure 2 The arrow direction in the embodiment shown radiates radially outward, and the magnetic flux directions of the first tangential flux permanent magnet 204 and the second tangential flux permanent magnet 205 are opposite. The magnetic flux directions of the first tangential flux permanent magnet 204 and the second tangential flux permanent magnet 205 are both arranged tangentially, and the magnetic flux directions both point to the radial flux permanent magnet 203. It is precisely because the tangential flux permanent magnets with opposite magnetic flux directions simultaneously point to the radial flux permanent magnet 203 that the total magnetic flux of the motor is forced to enter the yoke inside the magnetic conductive shaft 200 less and enter the air gap of the motor more, so that the motor has a magnetic concentration effect. There is a gap between adjacent magnetic steel slots 201 along the circumference of the magnetic conductive shaft 200, and the part of the magnetic conductive shaft 200 between adjacent magnetic steel slots 201 forms a soft magnetic magnetic adjustment pole 206. Among them, the magnetic conductive shaft 200 forms a magnetic yoke 207 on the inner side of the soft magnetic magnetic adjustment pole 206 and the permanent magnet magnetic concentration pole 202. The number of the soft magnetic tuning poles 206 and the permanent magnet focusing poles 202 is equal, and both are half of the number of motor poles.

[0037] Combination Figure 1 , Figure 2In the technical solution of the present invention, magnetic steel slots 201 are provided at intervals along the circumferential direction on the magnetic conductive shaft 200. The magnetic steel slots 201 are used to arrange and place permanent magnet magnetic poles 202. By designing the arrangement of the permanent magnet magnetic poles, the rotor permanent magnet magnetic pole structure has a magnetic focusing effect. The permanent magnet magnetic poles 202 are composed of tangential magnetic flux permanent magnets and radial magnetic flux permanent magnets 203, which will force the magnetic field lines of the electromagnetic field in the motor not to enter the magnetic conductive shaft 200. On the one hand, the magnetic focusing effect improves the air gap magnetic field strength of the motor, enhances the magnetic field energy storage of the motor, and effectively improves the power density and torque density of the motor; on the other hand, the magnetic field lines of the electromagnetic field in the motor are affected by the magnetic pole magnetic focusing effect, and most of the magnetic field does not enter the magnetic conductive shaft, which effectively suppresses the eddy current loss of the magnetic conductive shaft and greatly improves the heating problem on the rotor side.

[0038] At the same time, the spacing between the magnetic steel slots 201 on the magnetic shaft not only plays a role in limiting the permanent magnet magnetic pole 202, but also acts as a soft magnetic magnetic pole 206 of the motor. In low-speed and high-torque operating conditions, the soft magnetic magnetic pole 206 is magnetized to become a working pole, and its polarity is opposite to that of the permanent magnet magnetic pole 202; in deep magnetic weakening operating conditions, the soft magnetic magnetic pole 206 is weakly magnetized, and in addition to continuing to serve as a working pole, it also mainly provides a weak magnetic channel for the electromagnetic field in the motor. It is precisely because of the existence of the soft magnetic magnetic pole 206 that this surface-mounted permanent magnet motor can truly achieve deep magnetic weakening. It has been verified that the embodiment of the present invention is a relatively ideal "weak magnetic" speed expansion measure for permanent magnet synchronous motors. It solves the problem that the existing permanent magnet synchronous motor has a shallow weak magnetic speed regulation depth and the traditional embedded permanent magnet synchronous motor with weak magnetic speed regulation capability has a low limit speed.

[0039] The embodiments of the present invention solve the problems of low machining accuracy, low efficiency, low power density, large motor volume, low control accuracy and slow response time of the existing built-in induction motor for electric spindle.

[0040] In some embodiments, see Figure 1 , Figure 2 The outer diameter of the soft magnetic tuning pole 206 is the same as the outer diameter of the permanent magnet focusing pole 202. The outer diameter of the soft magnetic tuning pole 206 and the permanent magnet focusing pole 202 form a circumferential surface along the circumferential direction. The permanent magnet synchronous motor rotor structure also includes a protective cover 300. The protective cover 300 is mounted on the outer circle of the soft magnetic tuning pole 206 and the permanent magnet focusing pole 202 to resist the rotational centrifugal force of the permanent magnet focusing pole 202.

[0041] Furthermore, in some embodiments, the protective cover 300 includes a carbon fiber protective cover, and the carbon fiber protective cover is interference fit on the outer circumference of the soft magnetic tuning pole 206 and the permanent magnet focusing pole 202 .

[0042] In this embodiment, the traditional embedded laminated core rotor structure is abandoned, and a surface-mounted structure is used to directly attach the permanent magnet to the magnetic shaft, and then a high-strength carbon fiber protective cover is coated on the outer circle of the permanent magnet to resist the centrifugal force of the permanent magnet. Through this solid-like rotor topology, the limitation of the traditional embedded laminated core rotor structure on the motor's maximum speed is broken. As is known to all, the rotor surface linear speed of the traditional embedded laminated core rotor structure is difficult to exceed 150m / s, while the solid-like rotor topology structure coated with a high-strength carbon fiber protective cover in this embodiment easily exceeds 200m / s, achieving high speed.

[0043] It is understandable that the protective cover 300 may also be made of other materials such as a steel cover.

[0044] In some embodiments, see Figure 1 , Figure 2 The outer circumference of the magnetically conductive rotating shaft 200 is provided with two evenly distributed magnetic steel grooves 201 , and the magnetically conductive rotating shaft 200 forms two soft magnetic tuning poles 206 between the two magnetic steel grooves 201 .

[0045] Further, see Figure 3 The circumferential radian of each soft magnetic tuning pole 206 is δ1, the circumferential radian of each radial flux permanent magnet 203 is δ2, the circumferential radian of each first tangential flux permanent magnet 204 is δ3, and the circumferential radian of each second tangential flux permanent magnet 205 is δ4, δ1+δ2+δ3+δ4=π. That is, under the constraint of δ1+δ2+δ3+δ4=π, δ1, δ2, δ3 and δ4 can be freely combined. In the specific implementation, on the one hand, the air gap magnetic field of the motor should be close to the sine by adjusting the optimal combination of δ1, δ2, δ3 and δ4. This can effectively improve the ripple torque and cogging torque of the permanent magnet synchronous motor, thereby reducing the torque fluctuation of the motor, ensuring the machining accuracy of the electric spindle and weakening the vibration noise during the operation of the motor. At the same time, the sinusoidal air gap magnetic field effectively suppresses the core loss, eddy current loss and stray loss of the motor, thereby helping to improve the operation efficiency of the motor; on the other hand, the best combination of weak magnetic capacity can also be found by adjusting δ1, δ2, δ3 and δ4. That is, the combination of δ1, δ2, δ3 and δ4 should not only make the air gap magnetic field of the motor sinusoidal, but also meet the needs of deep weak magnetic speed regulation. Taking this case as an example, δ1=δ2=δ3=δ4=π / 4.

[0046] In this embodiment, the pole arc coefficients of the permanent magnet magnetic pole 202 and the soft magnetic magnetic pole 206 can be freely combined and designed. By adjusting the pole arc coefficients of the permanent magnet magnetic pole 202 and the soft magnetic magnetic pole 206 respectively, the air gap magnetic field of the motor tends to be sinusoidal, which can effectively improve the ripple torque and cogging torque of the permanent magnet synchronous motor, thereby reducing the torque fluctuation of the motor, ensuring the processing accuracy of the electric spindle and weakening the vibration noise during the operation of the motor. In addition, the sinusoidal air gap magnetic field suppresses the core loss, eddy current loss and stray loss of the motor, thereby improving the efficiency of the motor.

[0047] It is understandable that the outer circumferential surface of the magnetic conductive shaft 200 may be provided with more than two evenly distributed magnetic steel grooves 201. The specific technical principle is consistent with the above embodiment and will not be repeated herein.

[0048] In some embodiments, see Figure 4-Figure 6 The outer circumferential surface of the soft magnetic tuning pole 206 is provided with annular shallow grooves equidistantly distributed along the axial direction, wherein the depth of the annular shallow grooves is h1 and the width is b1; in this embodiment, the annular shallow grooves are opened on the outer circumference of the soft magnetic tuning pole 206, which cuts off the flow path of the eddy current field of the electromagnetic field in the motor on the surface and inside of the soft magnetic tuning pole 206, thereby effectively suppressing the eddy current loss of the soft magnetic tuning pole 206, thereby solving the problem of high rotor temperature when the high-speed permanent magnet motor is running in a deep weak magnetic state.

[0049] Further, see Figure 4 , Figure 5 , Figure 7 , the radial flux permanent magnet 203, the first tangential flux permanent magnet 204 and the second tangential flux permanent magnet 205 are equidistantly layered along the axial direction. The axial thickness of each layer of permanent magnet is b2, and the radial thickness of the permanent magnet is h2. The solution of layering the permanent magnets in this embodiment is to effectively suppress the eddy current loss of the permanent magnets by cutting off the flow path of the eddy current field of the electromagnetic field in the motor inside and on the surface of the permanent magnets, thereby solving the problem of high rotor temperature when the high-speed permanent magnet motor is running in a deep magnetic weakening state.

[0050] In a specific embodiment of the present invention, a surface-mounted permanent magnet synchronous motor with a rated power of 11Kw is ultimately rated to have a speed of 6000rpm and a maximum speed of over 60000rpm when weak magnetic field control is performed using a controller with a power supply voltage of 380VAC. That is, the depth of weak magnetic field speed regulation exceeds 10 times, achieving deep weak magnetic field.

[0051] The embodiment of the present invention further provides an electric spindle, comprising the motor in any embodiment. The electric spindle in the embodiment of the present invention can be used for turning and milling, which meets the use scenario of the electric spindle with low speed, high torque and high speed and constant power.

[0052] In the description of this specification, the description with reference to the terms "example", "embodiment" or "some 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.

[0053] Of course, the invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the invention, and these equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A permanent magnet synchronous motor rotor structure, characterized in that: It includes a magnetically conductive rotating shaft, the outer circumferential surface of which is provided with a plurality of magnetic steel grooves, the plurality of magnetic steel grooves are distributed along the circumference of the magnetically conductive rotating shaft, permanent magnet magnetic focusing poles are provided in the magnetic steel grooves, the permanent magnet magnetic focusing poles include radial magnetic flux permanent magnets, first tangential magnetic flux permanent magnets and second tangential magnetic flux permanent magnets, the first tangential magnetic flux permanent magnets and the second tangential magnetic flux permanent magnets are arranged on both sides of the radial magnetic flux permanent magnets along the circumference of the magnetically conductive rotating shaft, the magnetic flux directions of the first tangential magnetic flux permanent magnets and the second tangential magnetic flux permanent magnets are opposite, a gap is left between adjacent magnetic steel grooves along the circumference of the magnetically conductive rotating shaft, and the portion of the magnetically conductive rotating shaft between adjacent magnetic steel grooves forms soft magnetic tuning poles.

2. The permanent magnet synchronous motor rotor structure according to claim 1, characterized in that: The outer diameter of the soft magnetic flux-regulating pole is the same as the outer diameter of the permanent magnet flux-concentrating pole. The permanent magnet synchronous motor rotor structure also includes a protective sleeve, which is sleeved on the outer circles of the soft magnetic flux-regulating pole and the permanent magnet flux-concentrating pole.

3. The permanent magnet synchronous motor rotor structure according to claim 2, characterized in that: The protective cover comprises a carbon fiber protective cover, and the carbon fiber protective cover is interference fit on the outer circle of the soft magnetic tuning pole and the permanent magnet focusing pole.

4. The permanent magnet synchronous motor rotor structure according to claim 1, characterized in that: The outer circumferential surface of the magnetically conductive rotating shaft is provided with two evenly distributed magnetic steel grooves, and the magnetically conductive rotating shaft forms two soft magnetic tuning poles between the two magnetic steel grooves.

5. The permanent magnet synchronous motor rotor structure according to claim 4, characterized in that: The circumferential radian of each of the soft magnetic tuning poles is δ1, the circumferential radian of each of the radial flux permanent magnets is δ2, the circumferential radian of each of the first tangential flux permanent magnets is δ3, and the circumferential radian of each of the second tangential flux permanent magnets is δ4, and δ1+δ2+δ3+δ4=π.

6. The permanent magnet synchronous motor rotor structure according to claim 5, characterized in that: Said δ1=δ2=δ3=δ4.

7. The permanent magnet synchronous motor rotor structure according to claim 1, characterized in that: The outer circumferential surface of the soft magnetic tuning pole is provided with annular shallow grooves which are evenly distributed along the axial direction.

8. The permanent magnet synchronous motor rotor structure according to claim 1, characterized in that: The radial flux permanent magnets, the first tangential flux permanent magnets and the second tangential flux permanent magnets are equidistantly layered along the axial direction.

9. A motor, characterized in that: The invention comprises a permanent magnet synchronous motor rotor structure as claimed in any one of claims 1 to 8.

10. An electric spindle, characterized in that: A motor comprising the motor described in claim 9.

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