Rotor core structure, electric machine

Abstract

The utility model provides a rotor core structure, motor, wherein rotor core structure includes: main body is provided with a plurality of magnetic poles on the main body, a plurality of magnetic pole interval arrangement along the circumference of main body is provided with the lightening groove between two adjacent magnetic poles, the symmetry center line of two adjacent magnetic poles is L, along the radial direction of main body, the symmetry center line of lightening groove is m, the angle of slant pole rotor's slant pole is a, the angle between L and m is b, the number of lightening groove is X, it satisfies, b=(360 / 2X)-(a / 2). According to the utility model, can solve the existing segmented slant pole rotor in prior art when assembling, each segment slant pole rotor is stacked and is pressed after lightening hole can not be aligned, leading to the technical problem of rotor balance reduction.

Description

Technical Field

[0001] This utility model belongs to the field of motor technology, specifically relating to a rotor core structure and a motor. Background Technology

[0002] With the development of modern industry, built-in permanent magnet synchronous motors are increasingly widely used due to their advantages such as simple structure, high power density, wide speed range and high efficiency, especially in the field of electric vehicles.

[0003] Stator skew and rotor skew can effectively reduce tooth harmonics, cogging torque, and torque ripple. However, stator skew is complex to manufacture, so rotor skew is often used to achieve the same effect. Segmented rotor skew, as an effective NVH performance optimization technology for permanent magnet synchronous motors, has been applied in automotive electric drive systems in recent years. Segmented rotor skew mainly refers to the motor rotor being divided into several segments along the axial direction, with each segment rotating around the shaft at a certain angle. Segmented rotor skew not only effectively reduces tooth harmonics, improves cogging torque and torque ripple, but also affects the mechanical performance of the motor.

[0004] The weight-reducing slots on the rotor core play a crucial role in reducing weight, optimizing the magnetic circuit, improving mechanical balance, enhancing heat dissipation, and improving manufacturing convenience. Proper design and use of weight-reducing slots can significantly improve motor performance and reliability. Currently, research on skewed rotors neglects the impact of the alignment of the weight-reducing slots in each segment on the electromagnetic and mechanical performance of the motor. Because the weight-reducing slots in existing segmented skewed rotors are located on the symmetrical center lines of two adjacent magnetic poles, or the center lines of the weight-reducing slots coincide with the symmetrical center lines of two adjacent magnetic poles, the weight-reducing holes in each segment of the skewed rotor will also be skewed during assembly. This means that the weight-reducing holes cannot be aligned after the segments of the skewed rotor are stacked, leading to reduced rotor balance, decreased stiffness of the rotor assembly, and reduced modal characteristics.

[0005] Because existing segmented skewed rotors in the prior art cannot align the weight reduction holes after stacking the segments during assembly, resulting in reduced rotor balance, reduced stiffness and modal characteristics of the rotor assembly, this invention designs a rotor core structure and a motor. Utility Model Content

[0006] Therefore, this utility model provides a rotor core structure and a motor that can solve the technical problem in the prior art where the weight reduction holes cannot be aligned after the segments of the skewed rotor are stacked during assembly, resulting in a decrease in rotor balance.

[0007] To address the aforementioned problems, this utility model provides a rotor core structure, comprising: a main body, on which multiple magnetic poles are arranged at circumferential intervals, a weight-reducing slot is provided between adjacent magnetic poles, the symmetry center line of two adjacent magnetic poles is L, the symmetry center line of the weight-reducing slot is m along the radial direction of the main body, the skew angle of the skewed rotor is a, the angle between L and m is b, and the number of weight-reducing slots is X, which satisfies b = (360 / 2X) - (a / 2).

[0008] In some embodiments, the main body is provided with a central shaft hole, and the inner wall of the central shaft hole is provided with a first protrusion and a second protrusion in a radially inward direction. The first protrusion and the second protrusion are arranged symmetrically, and the center line n of the first protrusion coincides with the symmetrical center line m of the weight reduction groove in the radial direction of the central shaft hole, and / or the center line n of the second protrusion coincides with the symmetrical center line m of the weight reduction groove.

[0009] In some embodiments, the weight-reducing groove is triangular, and the weight-reducing groove includes a first side, a second side, and a third side connected in sequence, with the connection points of the first side, the second side, and the third side connected in sequence being rounded.

[0010] In some embodiments, the radius of the main body is R0, the radius of the central shaft hole is R1, and the minimum distance between the weight-reducing groove and the outer peripheral wall of the main body is d1, which satisfies R1=R0 / (3~3.3)d1.

[0011] In some embodiments, the minimum distance between the weight-reducing groove and the central shaft hole is d2, which satisfies d2=R0 / (4~4.3).

[0012] In some implementations, R1 ≥ d2.

[0013] In some implementations, the minimum distance between the first side and the magnetic pole is d3, which satisfies d3≥5mm.

[0014] In some embodiments, the first side and the second side form the apex of the weight-reducing groove, and the third side and the apex are arranged sequentially in a radially outward direction along the main body.

[0015] In some embodiments, a first corner is formed between the first side and the third side, and a second corner is formed between the second side and the third side, with the first corner and the second corner arranged sequentially along the circumference of the main body.

[0016] This utility model also provides an electric motor, which includes the aforementioned rotor core structure.

[0017] The rotor core structure and motor provided by this utility model have the following beneficial effects:

[0018] Using the symmetrical center line L between two adjacent magnetic poles 1, and the symmetrical center line m along the radial direction of the main body, the skew angle of the skewed rotor is a, the angle between L and m is b, and the number of weight-reducing slots 2 is X, which satisfies b = (360 / 2X) - (a / 2), the position of the weight-reducing slots 2 is located to ensure that the weight-reducing holes are completely aligned after each skewed rotor segment is stacked during the assembly of the segmented skewed rotor. This reduces the rotor imbalance caused by the misalignment of the weight-reducing slots between the skewed core segments and improves the stiffness and modality of the rotor assembly. Attached Figure Description

[0019] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the rotor core structure of this utility model. Figure 1 ;

[0021] Figure 2 This is a schematic diagram of the rotor core structure of this utility model. Figure 2 ;

[0022] Figure 3 This is a schematic diagram of the rotor core structure of this utility model. Figure 3 ;

[0023] Figure 4 This is a schematic diagram of the rotor core structure of this utility model assembled into a segmented skewed rotor pole;

[0024] Figure 5 This is a comparison of the modal frequency simulation of the rotor core structure of this utility model with that of the prior art;

[0025] Figure 6 This is a schematic diagram of the magnetic flux density region of the rotor core structure of this utility model.

[0026] The attached figures are labeled as follows:

[0027] 1. Magnetic pole; 2. Weight reduction groove; 3. Central shaft hole; 4. First protrusion; 5. Second protrusion; 6. First side; 7. Second side; 8. Third side. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0029] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0030] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0031] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0032] See also Figure 1-6As shown, according to an embodiment of this utility model, a rotor core structure is provided, comprising: a main body, on which a plurality of magnetic poles 1 are disposed, the plurality of magnetic poles 1 being arranged at circumferential intervals along the main body, a weight-reducing slot 2 being disposed between two adjacent magnetic poles 1, the symmetry center line of two adjacent magnetic poles 1 being L, the symmetry center line of the weight-reducing slot 2 being m along the radial direction of the main body, the skew angle of the skewed rotor being a, the angle between L and m being b, and the number of weight-reducing slots 2 being X, which satisfies b = (360 / 2X) - (a / 2). In this technical solution, see [reference needed]. Figure 1 and Figure 2 As shown, with L as the symmetrical center line between two adjacent magnetic poles 1, m as the symmetrical center line along the radial direction of the main body, a skew pole angle of a skewed rotor, an angle b between L and m, and X as the number of weight-reducing slots 2, b = (360 / 2X) - (a / 2) is used to position the weight-reducing slots 2. This ensures that the weight-reducing holes are completely aligned after the skewed rotor segments are stacked during assembly, reducing rotor imbalance caused by misalignment of the weight-reducing slots between skewed pole core segments and improving the stiffness and modal characteristics of the rotor assembly. Preferably, the number of weight-reducing slots 2 and magnetic poles 1 is both X.

[0033] In the rotor core structure of this utility model, the magnetic pole 1 can be a V-shaped magnetic steel groove, preferably a double-layer V-shaped magnetic steel groove arrangement to form a magnetic pole. Of course, other forms of magnetic pole structures are also acceptable.

[0034] In existing technology, the weight-reducing slots of skewed rotors are located on the center line of magnetic pole symmetry. During skewed assembly, misalignment of these slots can occur, and skew angles can also form between the weight-reducing slots of multiple rotor segments. These weight-reducing slots, also known as de-weighting slots or de-weighting holes, are typically used in motor design to reduce rotor mass, thereby improving dynamic performance and reducing vibration. When these weight-reducing slots become misaligned during manufacturing, it can negatively impact the electromagnetic performance of the motor, primarily in the following ways:

[0035] Non-uniform magnetic circuit: The magnetic field in a motor is generated by the stator windings and transmitted to the rotor through the air gap. If the weight-reducing slots on the rotor are not aligned, it will lead to an uneven distribution in the air gap, resulting in varying magnetic field strength at different locations. This non-uniformity in the magnetic circuit affects the magnetic flux distribution of the motor, which may cause fluctuations in the motor's electromagnetic torque, affecting the smoothness and efficiency of motor operation.

[0036] Increased eddy current losses: The presence of weight-reducing slots alters the magnetic permeability distribution in the rotor material. When the slots are misaligned, a more complex magnetic field distribution is formed inside the rotor, generating more eddy currents in the rotor material. Eddy currents consume electrical energy and are converted into heat energy, increasing motor losses and reducing motor efficiency.

[0037] Increased noise and vibration: Due to fluctuations in electromagnetic torque and additional losses caused by eddy current effects, the motor generates greater noise and vibration during operation. This not only affects the lifespan of the motor itself but also adversely impacts the mechanical system it drives.

[0038] In some embodiments, the main body is provided with a central shaft hole 3. Along the radial inward direction of the central shaft hole 3, the inner wall of the central shaft hole 3 is provided with a first protrusion 4 and a second protrusion 5. The first protrusion 4 and the second protrusion 5 are symmetrically arranged, and along the radial direction of the central shaft hole, the center line n of the first protrusion 4 coincides with the symmetrical center line m of the weight-reducing groove 2, and / or, the center line n of the second protrusion 5 coincides with the symmetrical center line m of the weight-reducing groove 2. In this technical solution, during assembly, a mark can be made on either the first protrusion 4 or the second protrusion 5. The first protrusion 4 and the second protrusion 5 of the central shaft hole 3 are symmetrically and evenly distributed along the central shaft hole 3. The center line of either the first protrusion 4 or the second protrusion 5 is n, and its center line n can coincide with the symmetrical center line of any weight-reducing groove 2. This ensures that the two keys of each section of the iron core after the rotor skew poles are aligned, facilitating the installation of the two keys with the main shaft to transmit motor torque.

[0039] Marking either the first protrusion 4 or the second protrusion 5 is to determine the positive and negative directions and rotation direction during the oblique pole stacking process. This is crucial to ensuring that the weight reduction slots of each iron core section are aligned after the stacking installation.

[0040] In the radial direction of the main body, the first protrusion 4 has its corresponding weight-reducing groove 2, and the two satisfy the condition that the center line n of the first protrusion 4 coincides with the center line m of the symmetry of the weight-reducing groove 2.

[0041] In the radial direction of the main body, the second protrusion 5 has its corresponding weight-reducing groove 2, and the two satisfy the condition that the center line n of the second protrusion 5 coincides with the center line m of the symmetry of the weight-reducing groove 2.

[0042] In some embodiments, the weight-reducing groove 2 is triangular, comprising a first side 6, a second side 7, and a third side 8 connected sequentially, with the joints of the first side 6, the second side 7, and the third side 8 rounded. In this technical solution, the weight-reducing groove 2 is located between two adjacent magnetic poles 1, and the apex of the weight-reducing groove 2 is arranged radially outward from the main body. Furthermore, the center line m of symmetry of the weight-reducing groove 2 extends radially outward from the main body. Preferably, the center line m of symmetry of the weight-reducing groove 2 is the midline of the apex of the weight-reducing groove 2, meaning the midline of the weight-reducing groove 2 symmetrically divides the apex. The joints of the first side 6, the second side 7, and the third side 8 are rounded, facilitating processing while preventing stress concentration at the joints.

[0043] In some embodiments, the radius of the main body is R0, the radius of the central shaft hole 3 is R1, and the minimum distance between the weight-reducing groove 2 and the outer peripheral wall of the main body is d1, which satisfies R1 = R0 / (3~3.3)d1. The minimum distance between the weight-reducing groove 2 and the central shaft hole 3 is d2, which satisfies d2 = R0 / (4~4.3). R1 ​​≥ d2. In this technical solution, see [reference needed]. Figure 3 Preferably, R0 = 130~180mm, and by using R1 = R0 / (3~3.3)d1≥d2 = R0 / (4~4.3) and d2 = R0 / (4~4.3), the weight reduction slot is kept away from the high magnetic density area of ​​the rotor, so as not to affect the output torque of the motor. At the same time, it prevents the weight reduction slot from getting close to the shaft hole, which would cause stress concentration problems on the side of the weight reduction slot close to the shaft hole.

[0044] See also Figure 5 As shown, compared with the rotor core structure of the prior art, the rotor core structure of this utility model has a significant improvement in modal frequency at the same order. By setting the angle and size of the weight reduction slot 2, and using only one type of rotor lamination, the rotor core structure of this utility model achieves rotor skewness while ensuring that the weight reduction slots are not skewed and are completely aligned. This reduces rotor imbalance caused by misalignment of the weight reduction slots between skewed pole core segments, improves the stiffness and modal characteristics of the rotor assembly, improves the NVH index of the drive motor, and enhances the overall vehicle comfort performance.

[0045] In some embodiments, the minimum distance between the first side 6 and the magnetic pole 1 is d3, which satisfies d3≥5mm. In this technical solution, the minimum distance between the first side 6 and the magnetic pole 1 is d3, which satisfies d3≥5mm. This maintains a certain distance between the weight-reducing groove 2 and the magnetic pole 1, in conjunction with [see also...]. Figure 6 As shown, in the rotor core structure of this utility model, the weight reduction groove 2 avoids the high magnetic density area of ​​the rotor, optimizes the magnetic circuit, reduces torque pulsation, and at the same time prevents stress concentration and output torque reduction problems near the magnetic poles.

[0046] In some embodiments, the first side 6 and the second side 7 form the apex corner of the weight-reducing groove 2, and the third side 8 is arranged sequentially with the apex corner in a radially outward direction along the main body. A first corner is formed between the first side 6 and the third side 8, and a second corner is formed between the second side 7 and the third side 8, and the first corner and the second corner are arranged sequentially along the circumference of the main body.

[0047] In this technical solution, the position of the weight reduction groove 2 is further defined, thereby reducing the impact of the weight reduction groove 2 on the rotor magnetic circuit.

[0048] This invention relates to a rotor core structure based on an integrated rotor topology with weight-reducing slots. It proposes a rotor topology that, while ensuring the rotor skew angle and number of skew pole segments, optimizes the electromagnetic and mechanical performance of the motor. This is achieved by designing the angle and size of the weight-reducing slots to align the skew poles on each segment of the skew pole core. This structure can further improve motor performance.

[0049] The rotor core structure of this utility model sets the protrusion angle relationship between the weight reduction slot, the magnet slot and the central shaft hole 3, so that while achieving rotor skew, the weight reduction slot is not skewed and is completely aligned. This reduces the rotor imbalance caused by the misalignment of the weight reduction slot between skewed pole core sections and improves the stiffness and modality of the rotor assembly.

[0050] The rotor core structure of this utility model optimizes the electromagnetic circuit of the rotor by optimizing the position, size and shape of the weight reduction slots, thereby improving the NVH index of the drive motor and enhancing the overall vehicle comfort performance.

[0051] The rotor core structure of this invention can achieve two or three skewed poles. The segmented skewed pole rotor is manufactured using a single processing mold, eliminating the need for other molds to produce rotor laminations of different models, thus saving mold development costs and R&D cycle. Furthermore, during the assembly of the segmented skewed pole rotor, after each segment of the skewed pole rotor is rotated at a certain angle and stacked, the weight-reducing groove is completely aligned with the protrusion of the central shaft hole 3, reducing rotor imbalance caused by misalignment of the weight-reducing grooves between the skewed pole core segments and improving the rigidity and modal characteristics of the rotor assembly.

[0052] See also Figure 4 The assembly steps for the skewed rotor core assembled using the rotor core structure of this utility model are as follows: First, place the first core segment A1 on the mounting platform. Then, flip the second core segment A2 relative to A1 so that A1 and A2 face opposite directions. Next, rotate the protruding keys with marked grooves on the left and right sides of A1 and A2 to align them. If there are two skewed segments, the core assembly is complete at this step. If there are three skewed segments, then align the third core segment A3 with the first core segment A1 facing upwards. Finally, rotate the protruding keys with marked grooves on the left and right sides of A1, A2, and A3 to align them. The core assembly is complete.

[0053] This utility model also provides an electric motor, including the rotor core structure described above.

[0054] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0055] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. The above description is only a preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A rotor core structure, characterized in that: include: The main body is provided with multiple magnetic poles (1), which are arranged circumferentially around the main body. A weight-reducing groove (2) is provided between two adjacent magnetic poles (1). The center line of symmetry between two adjacent magnetic poles (1) is L. The center line of symmetry of the weight-reducing groove (2) along the radial direction of the main body is m. The skew angle of the skewed rotor is a. The angle between L and m is b. The number of weight-reducing grooves (2) is X, which satisfies b = (360 / 2X) - (a / 2).

2. The rotor core structure according to claim 1, characterized in that: The main body is provided with a central shaft hole (3). In the radial direction inward of the central shaft hole (3), the inner wall of the central shaft hole (3) is provided with a first protrusion (4) and a second protrusion (5). The first protrusion (4) and the second protrusion are arranged symmetrically. In the radial direction of the central shaft hole, the center line n of the first protrusion (4) coincides with the center line m of the weight reduction groove (2), and / or the center line n of the second protrusion (5) coincides with the center line m of the weight reduction groove (2).

3. The rotor core structure according to claim 1, characterized in that: The weight-reducing groove (2) is triangular in shape. The weight-reducing groove (2) includes a first side (6), a second side (7), and a third side (8) connected in sequence. The first side (6), the second side (7), and the third side (8) are connected by rounded corners.

4. The rotor core structure according to claim 3, characterized in that: The radius of the main body is R0, the radius of the central shaft hole (3) is R1, and the minimum distance between the weight reduction groove (2) and the outer peripheral wall of the main body is d1, which satisfies R1=R0 / (3~3.3)d1.

5. The rotor core structure according to claim 4, characterized in that: The minimum distance between the weight reduction groove (2) and the central shaft hole (3) is d2, which satisfies d2=R0 / (4~4.3).

6. The rotor core structure according to claim 5, characterized in that: R1≥d2.

7. The rotor core structure according to claim 3, characterized in that: The minimum distance between the first side (6) and the magnetic pole (1) is d3, which satisfies that d3≥5mm.

8. The rotor core structure according to claim 3, characterized in that: The first side (6) and the second side (7) form the apex of the weight reduction groove (2), and the third side (8) and the apex are arranged in sequence along the radial outward direction of the main body.

9. The rotor core structure according to claim 3, characterized in that: A first corner is formed between the first side (6) and the third side (8), and a second corner is formed between the second side (7) and the third side (8). The first corner and the second corner are arranged sequentially along the circumference of the main body.

10. An electric motor, characterized in that: The rotor core structure includes any one of claims 1-9.

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