Motor and direct-drive rotary table

Abstract

The invention discloses a motor and a direct-drive rotary table, and the motor comprises a rotor assembly which comprises a rotor yoke and permanent magnets, the rotor yoke is provided with an annular groove, and the permanent magnets comprise an outer radial magnetic flux permanent magnet, an inner radial magnetic flux permanent magnet and an axial magnetic flux permanent magnet; the stator assembly comprises a stator yoke and a coil winding, the stator yoke is annular, one end of the stator yoke extends in the axial direction and extends into the annular groove, the other end of the stator yoke is installed on the cooling plate, and the coil winding is wound on the stator yoke; the coil winding includes a first side facing the outer radial flux permanent magnets, a second side facing the axial flux permanent magnets, a third side facing the inner radial flux permanent magnets, and a fourth side facing the cooling plate. One side of the coil winding is directly cooled by the cooling plate, so that the extreme heat dissipation of the motor is realized, the other three sides participate in electromagnetic reaction and provide electromagnetic torque, and the annular winding is utilized in the extreme manner, so that the cooling efficiency of the motor is greatly enhanced, and the torque density of the motor is greatly improved.

Description

Technical Field

[0001] The invention is used in the technical field of motors, and in particular relates to a motor and a direct-drive turntable. Background Art

[0002] The CNC turntable uses a direct-drive motor to avoid the precision loss caused by transmission mechanisms such as worm gears, ball screws, and gear reducers. When combined with high-precision servo drives and position sensors, it has the characteristics of high precision, high reliability, fast response, high efficiency, and low noise. Due to the above-mentioned significant advantages, the direct-drive turntable has become the first choice for high-end four-axis and five-axis CNC machine tools.

[0003] In addition to high precision, the excellent performance of the direct-drive turntable also places requirements on load capacity, that is, the motor of the direct-drive turntable should have the ability to output high torque, or, under the same installation space and quality requirements, a direct-drive turntable with higher output torque will be more competitive. High-torque motors have higher requirements on the heat dissipation effect of the motor. Therefore, how to make the supporting motor of the direct-drive turntable have higher torque and better heat dissipation effect has become a hot topic. Summary of the invention

[0004] 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 motor and a direct-drive turntable.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] In a first aspect, a motor comprises:

[0007] A rotor assembly, comprising a rotor yoke and permanent magnets, wherein the rotor yoke extends axially from a first end face to a second end face, the first end face is provided with an annular groove extending axially toward the second end face, the annular groove is terminated before extending to the second end face, and the permanent magnets comprise an outer radial flux permanent magnet arranged on an outer radial inner wall surface of the annular groove, an inner radial flux permanent magnet arranged on an inner radial inner wall surface of the annular groove, and an axial flux permanent magnet arranged on an axial inner wall surface of the annular groove;

[0008] The stator assembly includes a stator yoke and a coil winding, wherein the stator yoke is annular, one end of the stator yoke extends axially and extends into the annular groove, the other end of the stator yoke is mounted on a cooling plate, the coil winding is wound around the stator yoke, and the coil winding includes a first side facing the outer radial flux permanent magnet, a second side facing the axial flux permanent magnet, a third side facing the inner radial flux permanent magnet, and a fourth side facing the cooling plate.

[0009] In combination with the first aspect, in certain implementations of the first aspect, the outer radial flux permanent magnet, axial flux permanent magnet and inner radial flux permanent magnet located in the same radial cross-section form a group of permanent magnets, and multiple groups of the permanent magnets are arranged along the circumference of the annular groove, each group of the permanent magnets forms a U-shaped space in the annular groove, and each group of the permanent magnets has the same magnetic pole direction toward the inner side of the U-shaped space, and the magnetic poles of the multiple groups of permanent magnets along the circumference of the annular groove are alternately distributed as N poles and S poles.

[0010] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, an axial center hole is provided in the middle portion of the rotor yoke.

[0011] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the cooling plate includes a cooling water cover and a water sealing cover plate, the stator yoke is installed on the cooling water cover, the cooling water cover is provided with a cooling water trough at a position corresponding to the stator yoke, the water sealing cover plate is connected to the cooling water cover and covers the cooling water trough, and the cooling water cover and / or the water sealing cover plate are provided with a liquid inlet and a liquid outlet connected to the cooling water trough.

[0012] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the cooling water groove is arranged on a side surface of the cooling water cover away from the stator yoke, and the cooling water groove is an annular water groove extending along the circumferential direction of the stator yoke.

[0013] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, a through hole corresponding to the axial hole is provided in the middle of the cooling water cover, and the water sealing cover plate is installed on the cooling water cover from the side away from the stator yoke and covers the through hole.

[0014] In combination with the first aspect and the above-mentioned implementation methods, in some implementation methods of the first aspect, the stator yoke is provided with a plurality of radial winding grooves, and the plurality of radial winding grooves are arranged and distributed along the circumference of the stator yoke, and the radial winding grooves include an outer circumferential surface groove, a first end surface groove, an inner circumferential surface groove and a second end surface groove along the winding direction, and the coil winding includes a plurality of annular winding units wound in each of the radial winding grooves, a first side of the annular winding unit is located in the outer circumferential surface groove, a second side of the annular winding unit is located in the first end surface groove, a third side of the annular winding unit is located in the inner circumferential surface groove, and a fourth side of the annular winding unit is located in the second end surface groove.

[0015] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the stator yoke includes a radial yoke ring and an axial yoke iron, the radial yoke ring includes a plurality of first punching sheets arranged in a stacked manner, the first punching sheets include an annular sheet, the outer edge of the annular sheet is provided with an outer peripheral wing extending radially outward, the inner edge of the annular sheet is provided with an inner peripheral wing extending radially inward, the outer peripheral surface groove is formed between adjacent outer peripheral wings, and the inner peripheral surface groove is formed between adjacent inner peripheral wings, the axial yoke iron includes a plurality of second punching sheets arranged in a stacked manner, the axial yoke iron is connected to both ends of the radial yoke ring corresponding to the outer peripheral wings and the inner peripheral wings, and a first end face groove and a second end face groove are formed at both ends of the radial yoke ring.

[0016] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the radial yoke ring and the axial yoke iron are provided with axial holes, and the radial yoke ring and the axial yoke iron are connected to the cooling plate via a pull rod arranged in the axial hole.

[0017] In a second aspect, a direct-drive turntable comprises the motor described in any implementation of the first aspect.

[0018] One of the above technical solutions has at least one of the following advantages or beneficial effects: The technical solution of the present invention proposes an axial + radial three-dimensional magnetic flux multi-air gap permanent magnet synchronous motor, which is a motor with both axial magnetic field and radial magnetic field, and at least three-sided stator and rotor air gaps. The stator and rotor air gaps in the motor are the places where the motor exchanges electromechanical energy. The level of magnetic field energy storage is determined by the size of the air gap area, which directly determines the torque density of the motor. The present invention increases the air gap of the motor from the traditional single-sided (radial magnetic flux) or multi-sided (axial magnetic flux) to three-sided, effectively improving the electromechanical energy exchange place in the motor, thereby achieving the effect of improving the torque density of the motor; the present invention increases the number of effective coil sides of the winding from two in the traditional motor to at least three, which makes full use of the number of coil sides of the winding, so that the participation of the winding coil in the electromagnetic field in the motor is increased from the traditional 1 / 2 to 3 / 4, an increase of 50%, and similarly the torque density of the motor is also increased by 50%.

[0019] The winding of the motor is the main heat source of the motor. One side of the coil winding of the present invention is directly cooled by the cooling plate, thereby achieving the ultimate heat dissipation of the motor, and the other three sides are all involved in the electromagnetic reaction to provide electromagnetic torque. The annular winding is utilized to the extreme here. The innovative three-dimensional structure of the present invention changes the heat dissipation path of the traditional motor and achieves the ultimate heat dissipation effect of directly cooling the motor winding, thereby greatly enhancing the cooling efficiency of the motor and significantly improving the torque density of the motor.

[0020] 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

[0021] 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:

[0022] Figure 1 1 is a schematic diagram of the structure of an embodiment of the motor of the present invention;

[0023] Figure 2 yes Figure 1 An axonometric view of a rotor assembly of one embodiment is shown;

[0024] Figure 3 yes Figure 1 A cross-sectional view of a rotor assembly of one embodiment is shown;

[0025] Figure 4 yes Figure 1 An axial side view of a rotor assembly of one embodiment is shown;

[0026] Figure 5 yes Figure 1 an isometric view of a stator assembly of one embodiment shown;

[0027] Figure 6 yes Figure 1 A cross-sectional view of a stator assembly of one embodiment shown;

[0028] Figure 7 yes Figure 1 A schematic diagram of a stator yoke structure of an embodiment is shown;

[0029] Figure 8 yes Figure 1 A schematic diagram of a radial yoke ring structure of an embodiment is shown;

[0030] Fig. 9 yes Figure 1 A schematic diagram of the axial yoke structure of an embodiment shown;

[0031] Fig.10 yes Figure 1 A schematic diagram of the structure of a toroidal winding unit according to an embodiment of the present invention is shown;

[0032] Fig.11 It is a schematic structural diagram of an embodiment of the direct-drive turntable of the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] See also Figure 1-Figure 6 An embodiment of the present invention provides a motor, including a rotor assembly 100 and a stator assembly 200. The rotor assembly 100 includes a rotor yoke 101 and a permanent magnet. The rotor yoke 101 extends axially from a first end face 102 to a second end face 103. The first end face 102 is provided with an annular groove 104 extending axially toward the second end face 103. The annular groove 104 is terminated before extending to the second end face 103. The permanent magnet includes an outer radial flux permanent magnet 105 arranged on the outer radial inner wall surface of the annular groove 104, an inner radial flux permanent magnet 106 arranged on the inner radial inner wall surface of the annular groove 104, and an axial flux permanent magnet 107 arranged on the axial inner wall surface of the annular groove 104.

[0038] The stator assembly 200 includes a stator yoke 201 and a coil winding. The stator yoke 201 is annular. One end of the stator yoke 201 extends axially and extends into the annular groove 104. The other end of the stator yoke 201 is installed on the cooling plate 202. The coil winding is wound around the stator yoke 201. The coil winding includes a first side 203 facing the outer radial flux permanent magnet 105, a second side 204 facing the axial flux permanent magnet 107, a third side 205 facing the inner radial flux permanent magnet 106, and a fourth side 206 facing the cooling plate 202.

[0039] The technical solution of the present invention proposes an axial + radial three-dimensional magnetic flux multi-air gap permanent magnet synchronous motor, which is a motor with both axial magnetic field and radial magnetic field, and at least three-sided stator and rotor air gaps. The stator and rotor air gaps in the motor are the places where the motor exchanges electromechanical energy. The level of magnetic field energy storage is determined by the size of the air gap area, which directly determines the torque density of the motor. The present invention increases the air gap of the motor from the traditional single-sided (radial magnetic flux) or multi-sided (axial magnetic flux) to three-sided, effectively improving the electromechanical energy exchange place in the motor, thereby achieving the effect of improving the torque density of the motor; the present invention increases the number of effective coil sides of the winding from two in the traditional motor to at least three, which makes full use of the number of coil sides of the winding, so that the participation of the winding coil in the electromagnetic field in the motor is increased from the traditional 1 / 2 to 3 / 4, an increase of 50%. Similarly, the torque density of the motor is also increased by 50%.

[0040] The winding of the motor is the main heat source of the motor. One side of the coil winding of the present invention is directly cooled by the cooling plate 202, thereby achieving the ultimate heat dissipation of the motor, and the other three sides are all involved in the electromagnetic reaction to provide electromagnetic torque. The annular winding is utilized to the extreme here. The innovative three-dimensional structure of the present invention changes the heat dissipation path of the traditional motor and achieves the ultimate heat dissipation effect of directly cooling the motor winding, thereby greatly enhancing the cooling efficiency of the motor and greatly improving the torque density of the motor.

[0041] Specifically, see Figure 1 , Figure 5The coil winding is essentially a concentrated winding, and round copper wire or flat copper wire is generally used. An automatic winding machine is conveniently used to wind the coil winding into the slots of the stator core. The first side 203, the second side 204 and the third side 205 of the coil winding are all effective element sides of the coil winding, and all participate in the electromechanical energy exchange of the electromagnetic field and provide electromagnetic torque. In summary, the motor in this case has a total of three effective sides of the winding together with the semi-enclosed three-dimensional rotor described above, which is equivalent to three motors participating in the electromagnetic reaction together, while the windings of traditional motors are all two effective sides, and the other two only serve as connections and do not participate in electromechanical energy conversion. In this case, the number of effective coil sides is increased from two in the traditional motor to three, and the number of coil sides of the winding is fully utilized, so that the participation of the winding coil in the electromagnetic field in the motor is increased from the traditional 1 / 2 to 3 / 4, an increase of 50%. Similarly, the torque density of the motor can also be increased by 50% accordingly; in addition, after adopting the back-wound winding, the height of the coil end is also greatly reduced, which releases the valuable space in the motor, so that the power and torque of the motor can be increased by filling more effective materials of the motor. At the same time, the other fourth side 206 of the annular winding is directly forced to cool by the cooling plate 202, thereby achieving the ultimate heat dissipation of the motor. So far, each side of the coil winding has played an indispensable and important role, while the traditional motor, whether it is concentrated winding or distributed winding, has only two sides participating in the electromagnetic reaction and providing electromagnetic torque, and the remaining two sides only play a connecting role. Therefore, the structure of the four sides of the innovative invention in this case that play an extreme role is the core of the present invention.

[0042] In general, this case proposes a new type of motor topology, which is equivalent to a stator with a special structure, and together with three permanent magnet rotors, it forms a permanent magnet synchronous motor. This motor has unique extreme heat dissipation capabilities and axial + radial three-dimensional magnetic flux multi-air gap characteristics. Since a motor has multiple places for electromechanical energy exchange at the same time, the overall power density and torque density of the motor can be greatly improved.

[0043] In some embodiments, see Figure 4 The outer radial flux permanent magnet 105, the axial flux permanent magnet 107 and the inner radial flux permanent magnet 106 located in the same radial cross section form a group of permanent magnets. Multiple groups of permanent magnets are arranged along the circumference of the annular groove 104. Each group of permanent magnets forms a U-shaped space in the annular groove 104. The magnetic poles of each group of permanent magnets facing the inner side of the U-shaped space are in the same direction. The magnetic poles of multiple groups of permanent magnets along the circumference of the annular groove 104 are alternately distributed according to N and S poles. The rotor assembly 100 is the rotating element of the motor and is the actuator that converts electrical energy into mechanical energy. Figure 2 The rotor assembly 100 shown is composed of an axial flux permanent magnet 107, an outer radial flux permanent magnet 105 and an inner radial flux permanent magnet 106 to form a semi-enclosed three-dimensional structure, which is equivalent to having three rotors as a whole.

[0044] In other words, the axial flux permanent magnet 107 is divided into P N poles and P S poles, and is distributed at equal intervals along the circumference. At the same time, the outer radial flux permanent magnet 105 is also divided into P N poles and P S poles, and the inner radial flux permanent magnet 106 is also divided into P N poles and P S poles, which are also distributed at equal intervals along the circumference. In particular, in the same dimension, the polarity of all axial and radial permanent magnets is the same, that is, they are both N poles or both S poles. Here, P is the number of pole pairs of the motor. Taking this case as an example, P=5. Specifically, Figure 4 shown.

[0045] The outer radial flux permanent magnet 105, the axial flux permanent magnet 107 and the inner radial flux permanent magnet 106 can be connected to the rotor yoke 101 in a variety of ways, such as attaching the permanent magnet to the surface of the rotor yoke 101; or embedding the permanent magnet in a groove on the surface of the rotor yoke 101; or embedding the permanent magnet inside the rotor yoke 101. The magnet steel can also be a Halbach array magnet steel.

[0046] In some embodiments, to ensure that the motor has superior performance, the rotor yoke 101 is made of soft magnetic stainless steel or electrical pure iron with excellent magnetic conductivity; the permanent magnets are made of high-performance and high-grade sintered NdFeB materials.

[0047] In some embodiments, see Figure 1-Figure 4 An axial hole 108 is provided in the middle of the rotor yoke 101, and the axial hole 108 can be used to install a rotating shaft, etc. to realize a direct drive function.

[0048] The cooling plate 202 can be air-cooled or water-cooled. For example, in some embodiments, the cooling plate 202 is provided with cooling fins on the side away from the stator yoke 201. The heat generated during the operation of the coil winding can be forced to cool through the cooling plate 202 that cooperates with the fourth side 206, thereby achieving ultimate heat dissipation of the motor.

[0049] In some embodiments, see Figure 1 , Figure 6 The cooling plate 202 includes a cooling water cover 207 and a water sealing cover plate 208. The stator yoke 201 is mounted on the cooling water cover 207. The cooling water cover 207 is provided with a cooling water tank 209 at a position corresponding to the stator yoke 201. The water sealing cover plate 208 is connected to the cooling water cover 207 and shields the cooling water tank 209. The cooling water cover 207 and / or the water sealing cover plate 208 are provided with a liquid inlet 210 and a liquid outlet 211 connected to the cooling water tank 209. The water sealing cover plate 208 and the cooling water cover 207 together constitute a liquid cooling structure of the motor. The cooling water cover 207 and / or the water sealing cover plate 208 are provided with a liquid inlet 210 and a liquid outlet 211. When in use, the coolant flows in through the liquid inlet 210, flows through the cooling water tank 209, and then flows out from the liquid outlet 211 to remove the heat generated by the motor loss.

[0050] Further, see Figure 1 , Figure 6 In some embodiments, the cooling water tank 209 is disposed on a side surface of the cooling water cover 207 away from the stator yoke 201, and the cooling water tank 209 is an annular water tank extending along the circumferential direction of the stator yoke 201. The annular water tank extends along the distribution direction of the coil winding, and the annular water tank corresponds to the distribution position of the coil winding, and can quickly take away the heat generated by the loss of the coil winding.

[0051] In some embodiments, see Figure 1 , Figure 6 A through hole 212 corresponding to the axial hole 108 is provided in the middle of the cooling water cover 207. The cooling water cover 207 is annular. The water sealing cover plate 208 is installed on the cooling water cover 207 from the side away from the stator yoke 201 and covers the through hole 212. The cooling water cover 207 also has the function of sealing the axial hole 108 and the through hole to prevent impurities such as water vapor and dust from entering the interior of the motor.

[0052] In some embodiments, see Figure 5 , Figure 7 , Fig.10 The stator yoke 201 is provided with a plurality of radial winding grooves, which are arranged and distributed along the circumference of the stator yoke 201. The radial winding grooves include an outer peripheral groove 213, a first end groove 214, an inner peripheral groove 215, and a second end groove 216 along the winding direction. The coil winding includes a plurality of annular winding units 217 wound in each radial winding groove. The first side 203 of the annular winding unit 217 is located at the outer peripheral groove 213, the second side 204 of the annular winding unit 217 is located at the first end groove 214, the third side 205 of the annular winding unit 217 is located at the inner peripheral groove 215, and the fourth side 206 of the annular winding unit 217 is located at the second end groove 216. For example, in Figure 5 , Figure 7 In the illustrated embodiment, the stator yoke 201 is provided with 12 radial winding slots, and 12 annular winding units 217 are distributed in the radial winding slots and then connected according to a specific wiring method to form a symmetrical multi-phase motor winding that participates in the electromagnetic response of the motor.

[0053] The annular winding unit 217 is essentially a concentrated winding, and round copper wire or flat copper wire is generally used. The coil winding is conveniently wound into the radial winding slots of the stator yoke 201 using an automatic winding machine.

[0054] Further, in some embodiments, see Figure 7 , Figure 8 , Fig. 9The stator yoke 201 includes a radial yoke ring 218 and an axial yoke iron 219. The radial yoke ring 218 includes a plurality of first punchings arranged in layers. The first punchings include annular sheets. The outer edges of the annular sheets are provided with outer peripheral wings extending radially outward. The inner edges of the annular sheets are provided with inner peripheral wings extending radially inward. An outer peripheral surface groove 213 is formed between adjacent outer peripheral wings. An inner peripheral surface groove 215 is formed between adjacent inner peripheral wings. The axial yoke iron 219 includes a plurality of second punchings arranged in layers. The axial yoke iron 219 is connected to both ends of the radial yoke ring 218 corresponding to the outer peripheral wings and the inner peripheral wings, and a first end surface groove 214 and a second end surface groove 216 are formed at both ends of the radial yoke ring 218. Among them, the materials of the axial yoke iron 219 and the radial yoke ring 218 can be made of high-performance cold-rolled silicon steel sheets stacked together.

[0055] In some embodiments, see Figure 6 , Figure 8 , Fig. 9 The radial yoke ring 218 and the axial yoke iron 219 are provided with an axial hole 220, and the radial yoke ring 218 and the axial yoke iron 219 are connected to the cooling plate 202 through a tie rod 221 provided in the axial hole 220. The cooling plate 202 not only cools the motor, but also plays a key role in fixing the stator assembly 200. In order to ensure mechanical strength, stainless steel with high yield strength is specially selected.

[0056] The stator yoke 201 of the present invention has various structural forms, ample design space, and a very flexible manufacturing process, and can produce good effects.

[0057] See also Fig.11 An embodiment of the present invention further provides a direct-drive turntable, comprising the motor in any of the above embodiments.

[0058] For details, see Fig.11 The direct-drive turntable includes a base 301, a rotating shaft 302, and a turntable 303. The turntable 303 is connected to the rotating shaft 302, and the rotating shaft 302 is directly driven by a motor.

[0059] 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.

[0060] 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 motor, characterized in that: include: A rotor assembly, comprising a rotor yoke and permanent magnets, wherein the rotor yoke extends axially from a first end face to a second end face, the first end face is provided with an annular groove extending axially toward the second end face, the annular groove is terminated before extending to the second end face, and the permanent magnets comprise an outer radial flux permanent magnet arranged on an outer radial inner wall surface of the annular groove, an inner radial flux permanent magnet arranged on an inner radial inner wall surface of the annular groove, and an axial flux permanent magnet arranged on an axial inner wall surface of the annular groove; The stator assembly includes a stator yoke and a coil winding, wherein the stator yoke is annular, one end of the stator yoke extends axially and extends into the annular groove, the other end of the stator yoke is mounted on a cooling plate, the coil winding is wound around the stator yoke, and the coil winding includes a first side facing the outer radial flux permanent magnet, a second side facing the axial flux permanent magnet, a third side facing the inner radial flux permanent magnet, and a fourth side facing the cooling plate.

2. The motor according to claim 1, characterized in that The outer radial flux permanent magnet, axial flux permanent magnet and inner radial flux permanent magnet located in the same radial cross-section form a group of permanent magnets, and multiple groups of permanent magnets are arranged along the circumference of the annular groove. Each group of permanent magnets forms a U-shaped space in the annular groove. The magnetic poles of each group of permanent magnets facing the inner side of the U-shaped space are in the same direction, and the magnetic poles of the multiple groups of permanent magnets along the circumference of the annular groove are alternately distributed as N poles and S poles.

3. The motor according to claim 1, characterized in that An axial center hole is arranged in the middle of the rotor yoke.

4. The motor according to claim 3, characterized in that The cooling plate includes a cooling water cover and a water sealing cover plate. The stator yoke is installed on the cooling water cover. The cooling water cover is provided with a cooling water groove at a position corresponding to the stator yoke. The water sealing cover plate is connected to the cooling water cover and shields the cooling water groove. The cooling water cover and / or the water sealing cover plate are provided with a liquid inlet and a liquid outlet connected to the cooling water groove.

5. The motor according to claim 4, characterized in that The cooling water groove is arranged on a side surface of the cooling water cover away from the stator yoke, and the cooling water groove is an annular water groove extending along the circumferential direction of the stator yoke.

6. The motor according to claim 5, characterized in that A through hole corresponding to the axial center hole is provided in the middle of the cooling water cover, and the water sealing cover plate is installed on the cooling water cover from a side away from the stator yoke to cover the through hole.

7. The motor according to claim 1, characterized in that The stator yoke is provided with a plurality of radial winding grooves, which are arranged and distributed along the circumference of the stator yoke, and the radial winding grooves include an outer circumferential surface groove, a first end surface groove, an inner circumferential surface groove and a second end surface groove along the winding direction. The coil winding includes a plurality of annular winding units wound in each of the radial winding grooves, a first side of the annular winding unit is located in the outer circumferential surface groove, a second side of the annular winding unit is located in the first end surface groove, a third side of the annular winding unit is located in the inner circumferential surface groove, and a fourth side of the annular winding unit is located in the second end surface groove.

8. The motor according to claim 7, characterized in that The stator yoke includes a radial yoke ring and an axial yoke iron. The radial yoke ring includes a plurality of first punching sheets arranged in a stacked manner. The first punching sheets include an annular sheet. The outer edge of the annular sheet is provided with an outer peripheral wing extending radially outward. The inner edge of the annular sheet is provided with an inner peripheral wing extending radially inward. The outer peripheral surface grooves are formed between adjacent outer peripheral wings, and the inner peripheral surface grooves are formed between adjacent inner peripheral wings. The axial yoke iron includes a plurality of second punching sheets arranged in a stacked manner. The axial yoke iron is connected to both ends of the radial yoke ring corresponding to the outer peripheral wings and the inner peripheral wings, and a first end surface groove and a second end surface groove are formed at both ends of the radial yoke ring.

9. The motor according to claim 8, characterized in that The radial yoke ring and the axial yoke iron are provided with axial holes, and the radial yoke ring and the axial yoke iron are connected to the cooling plate through a pull rod arranged in the axial hole.

10. A direct drive turntable, characterized in that: A motor comprising any one of claims 1 to 9.

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