Rotor assembly and electric machine

Abstract

A rotor assembly and motor, the rotor assembly comprising: a rotor shaft; a rotor core coaxially arranged on the rotor shaft, the rotor core being provided with a plurality of first air holes; two rotor end plates respectively arranged on two sides of the rotor core, the rotor end plates being provided with a plurality of second air holes, each of the second air holes being communicated with the corresponding first air hole, and the rotor end plates being provided with a plurality of blades on the side away from the rotor core; and a rotor pressing ring arranged on the rotor shaft; by arranging the blades and the first air holes and the second air holes on the rotor end plates, the air flow is generated by the rotation of the rotor, the effective axial cooling air duct is formed, the heat dissipation capacity of the rotor assembly is significantly enhanced, the overall heat dissipation effect of the motor is improved, and the motor can exert higher performance.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically a rotor assembly and a motor. Background Technology

[0002] Currently, electric motors for new energy vehicles are rapidly developing towards higher voltage, higher speed, and higher integration. Among these, the requirements for motor heat dissipation capacity are gradually increasing due to the higher voltage and higher speed. How to effectively reduce motor temperature while controlling costs has become a very important topic.

[0003] In traditional motor structures, the rotor end plates of the rotor assembly are typically arranged in the form of solid discs on both sides of the rotor core. These plates serve to fix the magnets, isolate the magnetic field, and perform dynamic balancing. The rotor core, on the other hand, serves to conduct the magnetic circuit, fix the magnets, and transfer heat. The main heat dissipation path of the rotor assembly is that the magnets generate heat, which is then conducted to the rotor core, then to the rotor end plates, and finally to the air. This heat transfer path is relatively long, resulting in a relatively low heat transfer coefficient. Without additional oil cooling, the rotor temperature is relatively high, leading to relatively low overall efficiency.

[0004] The information disclosed in the background section of this invention is only intended to enhance the understanding of the general background of this invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a rotor assembly and a motor to solve at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A rotor assembly, comprising: Rotor shaft; A rotor core coaxially mounted on a rotor shaft, wherein a plurality of through-holes are provided on the rotor core; Two rotor end plates are respectively disposed on both sides of the rotor core. The rotor end plates are provided with multiple second air holes, each of which is connected to its corresponding first air hole. The side of the rotor end plate away from the rotor core is provided with multiple blades. A rotor pressure ring is disposed on the rotor shaft.

[0007] Furthermore, the number of the second air vents is the same as the number of the blades.

[0008] Furthermore, each of the second air vents is provided with one of the aforementioned blades.

[0009] Furthermore, the plurality of second air holes are evenly distributed along the circumference of the rotor end plate, and the plurality of blades are evenly distributed along the circumference of the rotor end plate.

[0010] Furthermore, the blade includes a first arc-shaped segment and a second arc-shaped segment, wherein the bending direction of the first arc-shaped segment is opposite to the bending direction of the second arc-shaped segment.

[0011] Furthermore, the second air vent is located inside the first arcuate segment of the corresponding blade.

[0012] Furthermore, the blades are arranged perpendicularly to the rotor end plate.

[0013] Furthermore, a positioning ring is provided at the end of the second air vent facing the first air vent, and the positioning ring is inserted into the first air vent.

[0014] Furthermore, the inner diameter of the positioning ring gradually increases from the outside to the inside, the inner diameter of the outer portion of the second air hole gradually increases from the inside to the outside, and the size of the outer opening of the second air hole is the same as the size of the first air hole.

[0015] The present invention also provides an electric motor, including a stator assembly and a rotor assembly as described above.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, by setting blades and through-holes (first and second) on the rotor end plate, utilizes the airflow generated by the rotor's own rotation to form an effective axial cooling airflow channel, significantly enhancing the heat dissipation capacity of the rotor assembly. This arrangement can also generate turbulence at both ends of the stator assembly, improving the heat dissipation capacity of the stator assembly, thereby improving the overall heat dissipation effect of the motor and enabling the motor to achieve higher performance.

[0017] 2. The present invention provides multiple blades on the rotor end plate so that when the rotor rotates, the blades can guide the airflow like a fan. In conjunction with the first and second air holes, the heat dissipation effect is further improved and the rotor temperature is effectively reduced.

[0018] 3. The rotor assembly of the present invention, the setting of the first air hole and the second air hole not only optimizes heat dissipation, but also realizes the weight reduction of rotor core and rotor end plate, which is conducive to reducing material cost and rotational inertia, and improving the dynamic response performance of the motor.

[0019] 4. The rotor assembly of the present invention has a compact structure and does not require the introduction of additional external cooling equipment or complex oil circuit system, thus achieving efficient cooling while controlling costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the rotor assembly structure in this embodiment; Figure 2 for Figure 1 Enlarged view of a portion of point A in the middle; Figure 3 This is a schematic diagram of the rotor end plate structure in this embodiment; Figure 4 This is a front view of the rotor end plate in this embodiment; Figure 5 This is a rear view of the rotor end plate in this embodiment; Figure 6 This is a side view of the rotor end plate in this embodiment; Figure 7 This is a schematic diagram of the rotor core (excluding magnets) structure in this embodiment; Figure 8 This is a diagram showing the positional relationship between the positioning ring and the first air hole in this embodiment; Figure 9 This is a simulation model diagram of the heat transfer coefficient in this embodiment; In the figure: 1. Rotor end plate; 11. Second air hole; 12. Blade; 121. First arc segment; 122. Second arc segment; 13. Positioning ring; 2. Rotor core; 21. First air hole; 22. Magnet slot; 3. Rotor shaft; 4. Rotor pressure ring. Detailed Implementation

[0021] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings. The following embodiments are exemplary and are only used to explain this application, and should not be construed as limiting this application. In the following description, the same reference numerals are used to denote the same or equivalent elements, and repeated descriptions are omitted.

[0022] In the description of this application, it should be understood that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the equipment or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the prepositions "first," "second," and "third," etc., are only used for the purpose of distinguishing the modified objects, and should not be construed as indicating or implying relative importance.

[0023] Furthermore, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] It should also be further understood that the term "and / or" as used in this application specification and the corresponding claims refers to any combination of one or more of the listed items and all possible combinations.

[0025] like Figure 1-9 As shown, this embodiment provides a rotor assembly, including a rotor shaft 3, a rotor core 2, two rotor end plates 1, and a rotor pressure ring 4. The rotor core 2 is generally cylindrical, with a shaft hole in its middle, through which the rotor core 2 is coaxially fixed to the rotor shaft 3. Multiple first air holes 21 are formed on the rotor core 2, penetrating both axial ends. These first air holes 21 are one of the main channels for cooling airflow. The two rotor end plates 1 are respectively disposed on both axial sides of the rotor core 2 and fixed to the rotor shaft 3. Each rotor end plate 1 has multiple second air holes 11, the number of which is the same as the number of first air holes 21. For example, if the rotor core 2 has six first air holes 21, then both rotor end plates 1 have six second air holes 11. The positions of these second air holes 11 correspond one-to-one with the positions of the first air holes 21 on the rotor core 2, and they are interconnected, forming an axial airflow channel penetrating the entire rotor assembly. On the side of the rotor end plate 1 facing away from the rotor core 2, i.e., on the exposed surface, multiple blades 12 are provided. The rotor pressure ring 4 is also provided on the rotor shaft 3, usually located on the outside of the rotor end plate 1, and is used to axially limit and fix the rotor core 2 and the rotor end plate 1 to ensure the structural stability of the rotor assembly.

[0026] like Figure 3-6 As shown, the rotor end plate 1 has an overall disc-shaped structure with a shaft hole in the middle for mounting with the rotor shaft 3. The rotor end plate 1 has two main sides: one side is the core mating surface facing the rotor core 2, and the other side is the exposed surface facing away from the rotor core 2.

[0027] The second air vent 11 on the rotor end plate 1 is an axial through hole penetrating the rotor end plate 1. The plurality of second air vents 11 are preferably evenly distributed along the circumference of the rotor end plate 1. In this embodiment, the number of second air vents 11 is six. It is understood that in other embodiments, the number of second air vents 11 can also be adjusted according to actual heat dissipation requirements and the size of the rotor end plate 1, for example, set to four, eight, or twelve, etc.

[0028] Multiple blades 12 are provided on the exposed surface. These blades 12 are three-dimensional structures protruding from the exposed surface. Preferably, the multiple blades 12 are also evenly distributed circumferentially along the rotor end plate 1, and the position of each blade 12 corresponds to the position of a second air vent 11. In this embodiment, the number of blades 12 is the same as the number of second air vents 11, both being six. Furthermore, a blade 12 is provided on the side of each second air vent 11. This one-to-one correspondence arrangement ensures that each blade 12 can effectively drive airflow to its corresponding second air vent 11 when rotating. Exemplarily, the blade 12 can be located on the counterclockwise or clockwise side of the second air vent 11, depending on the preset rotation direction of the motor.

[0029] like Figure 9 As shown, simulation calculations are performed on conventional rotor assemblies and the rotor assembly provided in this embodiment using a heat transfer coefficient simulation model. Figure 9 In the table, the upper left is the conventional rotor assembly, the lower left is the stator assembly corresponding to the conventional rotor assembly, the upper right is the rotor assembly provided in this embodiment, and the lower right is the stator assembly corresponding to the rotor assembly provided in this embodiment. The heat transfer coefficient results are shown in Table 1.

[0030] Table 1 In a preferred embodiment, each blade 12 may include a first arcuate segment 121 and a second arcuate segment 122. The bending direction of the first arcuate segment 121 is opposite to that of the second arcuate segment 122, which gives the blade 12 an overall "S"-shaped or reverse "S"-shaped curved profile. This arcuate structure can generate stronger air guidance capability when the rotor rotates.

[0031] Furthermore, the position of the second air hole 11 on the rotor end plate 1 corresponds specifically to the position of the blade 12. In this embodiment, the second air hole 11 is located inside the first arcuate segment 121 of its corresponding blade 12.

[0032] Furthermore, the relationship between the blade 12 and the exposed surface of the rotor end plate 1 is such that the blade 12 is set approximately perpendicular to the exposed surface. Here, "perpendicular" should be understood as the angle between the base of the blade 12 and the tangent of the exposed surface being close to 90 degrees, but certain manufacturing tolerances or small tilt angles designed to optimize performance are allowed.

[0033] As a preferred embodiment, in order to strengthen the stable connection between the rotor end plate 1 and the rotor core 2 and the alignment of the second air hole 11 and the first air hole 21, such as Figure 2As shown, in this embodiment, a positioning ring 13 is provided at the end of the second air hole 11 facing the first air hole 21 (i.e., the end located at the core mating surface). The positioning ring 13 is an annular structure protruding axially from the core mating surface, and the positioning ring 13 can be integrally formed with the rotor end plate 1. During assembly, the positioning ring 13 can be inserted into the first air hole 21 of the rotor core 2, thereby achieving radial positioning and connection between the rotor end plate 1 and the rotor core 2. This ensures that each second air hole 11 can be accurately aligned and connected with its corresponding first air hole 21, avoiding problems such as air duct blockage or reduced flow area caused by assembly deviations.

[0034] Furthermore, to make the airflow within the first air vent 21 and the second air vent 11 smoother and reduce energy loss, such as... Figure 8 As shown, this embodiment optimizes the internal shape of the positioning ring 13 and the second air vent 11. Specifically, the inner diameter of the positioning ring 13 is designed to gradually increase from the outside to the inside, where "outer" refers to the end of the positioning ring 13 connected to the rotor end plate 1, and "inner" refers to the end of the positioning ring 13. This structure forms a flared structure similar to a "trumpet mouth," which can guide air to enter and exit the second air vent 11 more smoothly. At the same time, the inner diameter of the outer part of the second air vent 11 (i.e., the part near the exposed surface) is designed to gradually increase from the inside to the outside, meaning that the second air vent 11 also has a flared structure at the opening on the exposed surface. Through this design, the size of the outer opening of the second air vent 11 can be made to match the size of the first air vent 21. This smooth transition design can effectively reduce the local resistance inside the air duct, reducing the flow rate and pressure loss of air when flowing through the air duct, thereby improving cooling efficiency.

[0035] like Figure 7 As shown, the rotor core 2 is cylindrical in shape and is typically formed by stacking multiple silicon steel sheets axially. A shaft hole is formed at the center of the rotor core 2 for mating with the rotor shaft 3. Multiple magnet slots 22 are formed on the rotor core 2 to accommodate and fix the magnets. The position and shape of the magnet slots 22 are determined according to the motor's magnetic circuit design and will not be elaborated here.

[0036] The first air hole 21 on the rotor core 2 is a through hole penetrating both axial ends of the core. The number and position of the first air holes 21 correspond exactly to the second air holes 11 on the rotor end plates 1. When the two rotor end plates 1 are installed on both sides of the rotor core 2, the first air holes 21 and the second air holes 11 located at both ends together form an axial channel penetrating the entire rotor assembly. The cross-sectional shape of the first air hole 21 can be circular, elliptical, or oblong, preferably circular to match the shape of the positioning ring 13, so as to facilitate positioning and assembly.

[0037] The first air vent 21 serves multiple functions. Firstly, its most basic function is as a cooling channel, allowing cooling air to flow through the rotor core 2 and directly remove heat from the magnets and rotor core 2. Secondly, the first air vent 21 also contributes to weight reduction. While maintaining the mechanical strength of the rotor core 2, opening these first air vents 21 can effectively reduce the amount of material used in the rotor core 2, thereby lowering material costs. Simultaneously, weight reduction also means a decrease in the rotational inertia of the rotor assembly, which is beneficial for improving the dynamic response performance of the motor. It is crucial to note that after opening the first air vent 21, the structure of the rotor core 2 must undergo strength simulation verification.

[0038] To further improve the cooling effect, the geometric parameters of the blade 12 can be optimized. For example, the air volume and air pressure can be adjusted by changing the height, thickness, radius of curvature, and the arc ratio of the first arc segment 121 and the second arc segment 122 of the blade 12 to adapt to the motor requirements of different speeds and heat outputs.

[0039] This embodiment also provides an electric motor, which includes a stator assembly and a rotor assembly as described in any of the above embodiments. Because this motor uses the aforementioned rotor assembly with an axial air-cooling structure, it possesses higher heat dissipation efficiency and power density. Under the same operating conditions, the motor has a lower rotor temperature, higher operating efficiency, and correspondingly improved reliability and lifespan. This type of motor is particularly suitable for the new energy vehicle field, where high power density and reliability are required.

[0040] For example, besides the "S"-shaped structure described above, other shapes can be used for the blade 12. For instance, the blade 12 can be a simple straight plate, tilted at a certain angle relative to the radial direction of the rotor end plate 1. Although this structure is simple to manufacture, its air-driving efficiency is not as good as that of the curved blade 12. As another example, the blade 12 can be an involute shape, with its radius of curvature gradually changing from the root to the tip to achieve better aerodynamic performance. Yet another example is that the blade 12 can also be an airfoil, with a cross-sectional shape similar to an aircraft wing, having a higher lift-to-drag ratio and capable of generating greater airflow with less energy loss. All forms of blade 12, as long as they are disposed on the rotor end plate 1 and used to drive air through the axial air vents, are within the scope of protection of this invention.

[0041] For example, the cross-sectional shapes of the first air vent 21 and the second air vent 11 can be other shapes besides circular. For instance, the cross-section of the air vent can be oblong (waist-shaped) to obtain a larger flow area within a limited radial space. The cross-section of the air vent can also be rectangular or fan-shaped to adapt to the shape of the magnet slot 22. The cross-section of the air vent can also be elliptical to better accommodate the stress distribution inside the rotor. Different cross-sectional shapes have their own advantages and disadvantages in terms of processing difficulty, flow capacity, and structural strength, and can be selected according to actual needs.

[0042] It should be noted that although the present invention has been disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A rotor assembly, characterized in that, include: Rotor shaft; A rotor core coaxially mounted on a rotor shaft, wherein a plurality of through-holes are provided on the rotor core; Two rotor end plates are respectively disposed on both sides of the rotor core. The rotor end plates are provided with multiple second air holes, each of which is connected to its corresponding first air hole. The side of the rotor end plate away from the rotor core is provided with multiple blades. A rotor pressure ring is disposed on the rotor shaft.

2. A rotor assembly as described in claim 1, characterized in that, The number of the second air vents is the same as the number of the blades.

3. A rotor assembly as described in claim 2, characterized in that, Each of the second air vents is provided with one of the aforementioned blades.

4. A rotor assembly as described in claim 2, characterized in that, The plurality of second air holes are evenly distributed along the circumference of the rotor end plate, and the plurality of blades are evenly distributed along the circumference of the rotor end plate.

5. A rotor assembly as described in claim 1, characterized in that, The blade includes a first arc segment and a second arc segment, wherein the bending direction of the first arc segment is opposite to the bending direction of the second arc segment.

6. A rotor assembly as described in claim 5, characterized in that, The second air vent is located inside the first arc-shaped segment of the corresponding blade.

7. A rotor assembly as claimed in claim 1, characterized in that, The blades are arranged perpendicularly to the rotor end plate.

8. A rotor assembly as claimed in claim 1, characterized in that, A positioning ring is provided at the end of the second air vent facing the first air vent, and the positioning ring is inserted into the first air vent.

9. A rotor assembly as described in claim 8, characterized in that, The inner diameter of the positioning ring gradually increases from the outside to the inside, and the inner diameter of the outer part of the second air hole gradually increases from the inside to the outside. The size of the outer opening of the second air hole is the same as the size of the first air hole.

10. An electric motor, characterized in that, It includes a stator assembly and a rotor assembly according to any one of claims 1-9.

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