A permanent magnet motor

Abstract

This invention relates to a permanent magnet motor, comprising: a stator assembly and a rotor assembly; the stator assembly includes a first stator and a second stator located at the axial end of the first stator; the rotor assembly includes a first rotor and a second rotor fixed to a rotor shaft and arranged axially, the first rotor being located radially inner to the first stator, and a radial gap being formed between the first rotor and the second rotor to form a radial main magnetic flux between the first rotor and the first stator; the second rotor axially faces the second stator, and an axial gap is formed between the second rotor and the second stator to form an axial main magnetic flux between the second rotor and the second stator. This invention improves torque by forming a hybrid magnetic circuit using radial and axial main magnetic fluxes, while eliminating end leakage magnetic effects, improving motor material utilization, increasing power density, making the motor structure more compact, and improving load stability.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more particularly to a permanent magnet motor. Background Technology

[0002] In recent years, with the development of high-end equipment manufacturing, the demand for various types of robots has been increasing. Using robots in many high-intensity work environments can greatly improve production efficiency and reduce labor costs. As an ideal power source for robots, permanent magnet synchronous motors (PMSMs) are facing higher performance requirements. Under the overall industry trend, PMSMs are developing towards higher power density, lighter weight, and smaller size.

[0003] Currently, permanent magnet synchronous motors are widely used in electric vehicles, railcars and trolleybuses, aerospace, elevators, home appliances, and marine industries. The development of high-power, high-speed, high-torque, high-efficiency, and lightweight permanent magnet synchronous motors has a significant positive impact on energy conservation, environmental protection, and high-efficiency, high-quality service. However, existing permanent magnet synchronous motors have the following drawbacks:

[0004] Most existing permanent magnet synchronous motors for robots have radial flux. Due to the limitation of inner diameter, it is often necessary to increase the overall length of the machine to improve torque, which is not suitable for many robot applications with compact spatial structures.

[0005] For many special occasions, high inertia models are required, but this is also subject to limitations imposed by the installation structure. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a permanent magnet motor.

[0007] The permanent magnet motor provided by the present invention includes: a stator assembly and a rotor assembly; the stator assembly includes a first stator and a second stator located on the axial end side of the first stator; the rotor assembly includes a first rotor and a second rotor fixed on a rotor shaft and arranged axially, the first rotor being located radially inside the first stator, and a radial gap being formed between the first rotor and the second rotor to form a radial main magnetic flux between the first rotor and the first stator; the second rotor facing the second stator axially and an axial gap being formed between the second rotor and the second stator to form an axial main magnetic flux between the second rotor and the second stator.

[0008] In some embodiments, the first stator includes a first stator core and a first coil winding wound on the first stator core; the second stator includes a second stator core and a second coil winding wound on the second stator core, wherein the second coil winding is connected in series with the first coil winding.

[0009] In some embodiments, the first rotor includes a first rotor core fixed on the rotor shaft and a plurality of first magnets disposed on the first rotor core and distributed circumferentially, the first magnets forming a radial main magnetic flux with the first coil winding; the second rotor includes a second rotor core fixed on the rotor shaft and a plurality of second magnets disposed on the second rotor core, the second rotor core being located axially to the side of the first rotor core, the second magnets facing the second coil winding, the second magnets forming an axial main magnetic flux with the second coil winding.

[0010] In some embodiments, the first surface of the second stator core is provided with a plurality of second stator teeth, and the second coil winding is wound on each of the second stator teeth; the second surface of the second rotor core is provided with a plurality of second receiving slots, and the second magnet is provided in each of the second receiving slots, wherein the second surface faces the first surface axially.

[0011] In some embodiments, the second stator core is integrally formed into a disc shape, and the second stator teeth are evenly distributed along the circumference of the disc-shaped second stator core; and / or, the second rotor core is integrally formed into a disc shape, and the second magnets are evenly distributed along the circumference of the disc-shaped second rotor core.

[0012] In some embodiments, the first stator core includes a first stator tooth formed by stacking silicon steel sheets, and the first coil winding is wound on each of the first stator teeth; the first rotor core includes a first receiving groove formed by stacking silicon steel sheets, and the first magnet is disposed in each of the first receiving grooves.

[0013] In some embodiments, the number of the first stator teeth and the second stator teeth is 6; the number of the first magnet and the second magnet is 5.

[0014] In some embodiments, the second stator is fixed to the first stator at a first or second axial end; the second rotor is located on the first or second axial side of the first rotor.

[0015] In some embodiments, there are two second stators, which are respectively fixed to the first end and the second end of the first stator along the axial direction; there are two second rotors, which are respectively located on the first side and the second side of the first rotor along the axial direction.

[0016] In some embodiments, the second stator is fixed to the rear end cover of the permanent magnet motor; the second rotor is located on the second side of the first rotor axis, and the second side is adjacent to the rear end cover.

[0017] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0018] The stator and rotor of this invention are both composite structures. The first stator and the first rotor are respectively a radial flux stator and a radial flux rotor, which are coupled to form a radial main flux. The second stator and the second rotor are respectively an axial stator and an axial rotor, which are coupled to form an axial main flux. The radial main flux and the axial main flux form a hybrid magnetic circuit, which improves torque. At the same time, the radial flux and axial flux generated by the permanent magnet are both utilized, eliminating the end leakage flux effect, improving the utilization rate of motor materials, reducing the weight of the motor, increasing the power density, making the motor structure more compact, and improving load stability.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0020] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0021] Figure 1 This is an exploded view of a permanent magnet motor according to an exemplary embodiment of the present invention;

[0022] Figure 2 This is a cross-sectional view of a permanent magnet motor according to an exemplary embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the first stator core structure according to an exemplary embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the second stator core structure according to an exemplary embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the first rotor core structure according to an exemplary embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the second rotor core structure according to an exemplary embodiment of the present invention;

[0027] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0028] In the description of this invention, it should be noted that the terms "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "contact," and "communication" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] like Figures 1-6 As shown, this embodiment of the invention provides a permanent magnet motor with a composite structure of axial and radial magnetic flux, which makes use of both the radial and axial magnetic flux generated by the permanent magnet, eliminates the end leakage magnetic effect, improves the utilization rate of motor materials, reduces the weight of the motor, increases the power density, and can effectively increase the moment of inertia of the motor without increasing the axial dimension, making the motor structure more compact and improving load stability.

[0031] The permanent magnet motor of this invention includes a stator assembly and a rotor assembly.

[0032] The stator assembly includes a first stator 11 and a second stator 12 located on the axial end side of the first stator 11. The first stator 11 has a first end and a second end opposite each other in the axial direction. The second stator 12 may be located on the first end side or the second end side of the first stator 11.

[0033] The rotor assembly includes a first rotor 21 and a second rotor 22 fixed on the rotor shaft 30 and arranged axially. Preferably, the first rotor 21 and the second rotor 22 are mounted side by side on the rotor shaft 30 in the axial direction and rotate synchronously. They can be positioned and spaced apart by a shoulder on the rotor shaft. The first rotor 21 is located radially inside the first stator 11, that is, the first stator 11 is sleeved on the outer periphery of the first rotor 21. A radial gap (air gap) is formed between the first rotor 21 and the second rotor to form a radial main magnetic flux between the first rotor 21 and the first stator 11. The second rotor 22 faces the second stator 12 axially, and an axial gap (air gap) is formed between the second rotor 22 and the second stator 12 to form an axial main magnetic flux between the second rotor 22 and the second stator 12.

[0034] The stator and rotor of this invention are both composite structures. The first stator 11 and the first rotor 21 are respectively a radial flux stator and a radial flux rotor, which are coupled to form a radial main flux. The second stator 12 and the second rotor 22 are respectively an axial stator and an axial rotor, which are coupled to form an axial main flux. The radial main flux and the axial main flux form a mixed magnetic circuit to improve torque. Furthermore, the axial stator and the radial stator are assembled together, so that both the radial and axial flux generated by the permanent magnet are utilized, eliminating the end leakage flux effect, improving the utilization rate of motor materials, reducing the weight of the motor, increasing the power density, making the motor structure more compact, and improving load stability.

[0035] In some examples, the second stator 12 is fixed to either the first or second axial end of the first stator 11; the second rotor 22 is located on either the first or second axial side of the first rotor 21. That is, the second stator 12 of the permanent magnet motor of the present invention can be fixed to the first stator 11 to form a composite structure, and the fixing position can be any end of the first stator 11 (either the first or the second end). Similarly, the second rotor 22 can be fixed to the rotor shaft 30 and located on either the first or second axial side of the first rotor 21, ensuring that the second rotor 22 and the second stator 12 face each other to generate axial magnetic flux.

[0036] However, this is not the only option. In other embodiments, two second stators 12 may be provided, fixed to the first and second ends of the first stator 11 along the axial direction, respectively. That is, a second stator 12 may be provided at both ends of the first stator 11 along the axial direction. Similarly, two second rotors 22 may be provided, located on the first and second sides of the first rotor 21 along the axial direction, respectively. This forms two axial magnetic paths, further improving the power density of the motor.

[0037] The present invention is not limited thereto. In some other embodiments, the second stator 12 can be fixed on the rear end cover of the permanent magnet motor. Correspondingly, the second rotor 22 is located on the second side of the first rotor 21 along the axial direction, with the second side adjacent to the rear end cover, so that the second rotor 22 and the second stator 12 on the rear end cover face each other to generate axial magnetic flux.

[0038] In other words, the arrangement position and quantity of the second stator 12 and the second rotor 22 in this embodiment of the invention can be adjusted as needed.

[0039] In some embodiments, the first stator 11 includes a first stator core and a first coil winding 112 wound around the first stator core; the second stator 12 includes a second stator core and a second coil winding 122 wound around the second stator core, the second coil winding 122 being connected in series with the first coil winding 112. In one example, the first stator core includes first stator teeth 111 formed by stacking silicon steel sheets, the first coil winding 112 being wound around each first stator tooth 111; the second stator core may be disc-shaped, the first surface of the second stator core being provided with a plurality of second stator teeth 121 evenly distributed along its circumference, the second coil winding 122 being wound around each second stator tooth 121.

[0040] The first rotor 21 includes a first rotor core fixed on a rotor shaft 30 and a plurality of first magnets 212 arranged circumferentially on the first rotor core. The first magnets 212 and the first coil winding 112 form a radial main magnetic flux. For example, the first rotor core includes a first receiving groove 211 formed by stacking silicon steel sheets, and a first magnet 212 is disposed in each first receiving groove 211.

[0041] The second rotor 22 includes a second rotor core fixed on the rotor shaft 30 and a plurality of second magnets 222 disposed on the second rotor core. The second rotor core is located axially to the side of the first rotor core, and the second magnets 222 face the second coil winding 122. The second magnets 222 and the second coil winding 122 form an axial main magnetic flux. For example, the second rotor core may be disc-shaped, and the second surface of the second rotor core is provided with a plurality of second receiving slots 221 evenly distributed along its circumference. The second magnets 222 are disposed in each second receiving slot 221, wherein the second surface of the second rotor 22 axially faces the first surface of the second stator core.

[0042] The present invention provides an axial rotor (second rotor 22) on the axial side of the radial rotor (first rotor 21). The axial rotor has a disc structure, which increases the output torque and motor inertia without the need for an additional inertia disc or axial dimension, making the inertia disc and axial rotor integrated, and the whole machine structure more compact.

[0043] In some examples, the number of the first stator teeth 111 and the second stator teeth 121 is 6; the number of the first magnet 212 and the second magnet 222 is 5. By using a radial stator (first stator 11) and a radial rotor (first rotor 21) to form a 6 / 5 slot pole, the back EMF harmonic content is minimized, thereby improving the motor output torque.

[0044] It can be further understood that in this disclosure, "multiple" refers to two or more, and other quantifiers are similar. "And / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0045] It is further understood that the terms "first," "second," etc., are used to describe various types of information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another, and do not indicate a specific order or degree of importance. In fact, the expressions "first," "second," etc., are completely interchangeable. For example, without departing from the scope of this disclosure, first information can also be referred to as second information, and similarly, second information can also be referred to as first information.

[0046] It is further understood that although operations are described in a specific order in the accompanying drawings in the embodiments of this disclosure, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all of the shown operations to be performed to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0047] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0048] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A permanent magnet motor, characterized in that, include: Stator assembly and rotor assembly; The stator assembly includes a first stator and a second stator located at the axial end of the first stator; the first stator includes a first stator core and a first coil winding wound on the first stator core; the second stator includes a second stator core and a second coil winding wound on the second stator core. The rotor assembly includes a first rotor and a second rotor fixed on a rotor shaft and arranged axially. The first rotor is located radially inside the first stator, and a radial gap is formed between the first rotor and the first stator to form a radial main magnetic flux between the first rotor and the first stator. The second rotor faces the second stator axially, and an axial gap is formed between the second rotor and the second stator to form an axial main magnetic flux between the second rotor and the second stator. The first rotor includes a first rotor core fixed on the rotor shaft and a plurality of first magnets arranged circumferentially on the first rotor core. The first magnets and the first coil winding form a radial main magnetic flux. The second rotor includes a second rotor core fixed on the rotor shaft and a plurality of second magnets arranged on the second rotor core. The second rotor core is located axially to the side of the first rotor core, and the second magnets face the second coil winding. The second magnets and the second coil winding form an axial main magnetic flux.

2. The permanent magnet motor according to claim 1, characterized in that, The second coil winding is connected in series with the first coil winding.

3. The permanent magnet motor according to claim 1, characterized in that, The first surface of the second stator core is provided with a plurality of second stator teeth, and the second coil winding is wound on each of the second stator teeth; The second rotor core has a plurality of second receiving slots on its second surface, and a second magnet is provided in each of the second receiving slots, wherein the second surface faces the first surface axially.

4. The permanent magnet motor according to claim 3, characterized in that, The second stator core is integrally formed into a disc shape, and the second stator teeth are evenly distributed along the circumference of the disc-shaped second stator core; and / or, The second rotor core is integrally formed into a disc shape, and the second magnets are evenly distributed along the circumference of the disc-shaped second rotor core.

5. The permanent magnet motor according to claim 3, characterized in that, The first stator core includes a first stator tooth formed by stacking silicon steel sheets, and the first coil winding is wound on each of the first stator teeth; The first rotor core includes a first receiving groove formed by stacking silicon steel sheets, and the first magnet is disposed in each of the first receiving grooves.

6. The permanent magnet motor according to claim 5, characterized in that, The number of the first stator teeth and the second stator teeth is 6; The number of the first magnet and the second magnet is 5.

7. The permanent magnet motor according to any one of claims 1-6, characterized in that, The second stator is fixed at either the first or second axial end of the first stator; The second rotor is located on the first or second axial side of the first rotor.

8. The permanent magnet motor according to any one of claims 1-6, characterized in that, The second stator is provided in two parts, which are respectively fixed to the first end and the second end of the first stator along the axial direction; The second rotor is provided in two parts, located on the first side and the second side of the first rotor axis, respectively.

9. The permanent magnet motor according to any one of claims 1-6, characterized in that, The second stator is fixed to the rear end cover of the permanent magnet motor; The second rotor is located on the second side of the first rotor along its axial direction, and the second side is adjacent to the rear end cover.

Images