Rotor lamination and forming method therefor, rotor iron core, servo motor and robot
By setting grooves and/or protrusions on the outer circle of the rotor lamination and adopting a step-by-step forming process, the problem of the decrease in dimensional accuracy of the outer contour of the rotor core during the stamping process is solved, and high-precision machining of the outer circle of the rotor and improvement of robot positioning accuracy are achieved.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- GREE ELECTRIC APPLIANCE INC OF ZHUHAI
- Filing Date
- 2025-09-10
- Publication Date
- 2026-06-25
AI Technical Summary
In the prior art, the outer contour of the rotor core of the servo motor is easily affected by the mold stress during the stamping process, which leads to a decrease in dimensional accuracy, distortion of the air gap magnetic flux density waveform, and an increase in harmonic content, thereby affecting the positioning accuracy of the robot.
Grooves and/or protrusions are provided on the outer circle of the rotor lamination. A step-by-step forming process is adopted. The grooves or protrusions provide connection and positioning during the stamping process, ensuring the machining accuracy and dimensional stability of the outer circle of the rotor and reducing the impact of stamping stress.
This improved the machining accuracy of the rotor's outer diameter, reduced motor cogging torque and torque pulsation, enhanced the robot's positioning accuracy and yield, and reduced scrap and reprocessing costs.
Smart Images
Figure CN2025120480_25062026_PF_FP_ABST
Abstract
Description
Rotor laminations and their forming methods, rotor cores, servo motors and robots
[0001] This application claims priority to Chinese invention patent application number "202411863640.5", filed on "December 17, 2024", entitled "Rotor lamination and its forming method, rotor core, servo motor and robot". Technical Field
[0002] This application relates to the field of robotics technology, and more specifically, to a rotor lamination and its forming method, a rotor core, a servo motor, and a robot. Background Technology
[0003] In the design and manufacturing of servo motors, the precision of the rotor core is one of the key factors determining motor performance. This precision is mainly determined by the material properties, die design, and stamping process parameters during the stamping process. Electromagnetic steel sheets, typically between 0.2mm and 1mm thick, exhibit characteristics of being thin, lightweight, and efficient, making them ideal for manufacturing high-speed rotating motor components. However, precisely because of their thinness, the steel sheet is highly susceptible to die stress during the stamping process, especially in the shaping stage of complex rotor core shapes, such as sharp angles, curves, or irregular shapes. This makes dimensional control a significant challenge.
[0004] Ideally, when the outer contour of the servo motor's rotor core perfectly matches the design dimensions, the air gap magnetic flux density waveform should be a perfect sine wave. This is because a sinusoidal magnetic flux density distribution ensures a uniform magnetic field distribution within the motor, effectively reducing cogging torque and torque ripple, thereby improving the motor's efficiency and operational stability. Cogging torque arises from the non-uniformity of the magnetic circuit between the stator and rotor when the motor is under no-load conditions; it affects the motor's starting performance and operational smoothness. Torque ripple, on the other hand, causes fluctuations in power output during motor operation, affecting overall control accuracy.
[0005] However, when the dimensional accuracy of the rotor core's outer contour decreases, deviating from the ideal design value, the air gap magnetic flux density waveform of the motor will be significantly distorted. This distortion leads to the introduction of additional harmonic components in the waveform, resulting in a substantial increase in harmonic content. This increase in harmonic content directly leads to increased cogging torque and torque pulsation, ultimately reducing the robot's positioning accuracy. Summary of the Invention
[0006] The main objective of this application is to provide a rotor lamination and its forming method, a rotor core, a servo motor, and a robot, which can improve the stamping accuracy of the outer contour of the rotor lamination, reduce the cogging torque and torque pulsation of the motor, and improve the positioning accuracy of the robot.
[0007] To achieve the above objectives, according to one aspect of this application, a rotor lamination is provided, including a lamination body having a rotor outer circle. In one extreme case, the rotor outer circle of the lamination body is provided with a groove recessed inward relative to the rotor outer circle and / or a protrusion protruding outward relative to the rotor outer circle.
[0008] In some embodiments, the protrusion or groove has two endpoints at both ends along the circumferential direction, and the included angle formed by the line connecting the two endpoints and the center of the lamination body is γ, 1°≤γ≤70 / P°, where P is the number of rotor poles.
[0009] In some embodiments, the angle between the line connecting the end point of the protrusion or groove near the d-axis and the center of the lamination body and the d-axis is α, where 20° / P≤α≤80° / P, and P is the number of rotor poles.
[0010] In some embodiments, the diameter of the outer circle of the rotor is Ф. When a protrusion is provided on the outer circle of the rotor, the maximum diameter of the circle containing the point on the outer contour of the protrusion is ФC1, with the center of the lamination body as the center, Ф<ФC1≤Ф+2 / 3×δ, where δ is the air gap width. When a groove is provided on the outer circle of the rotor, the minimum diameter of the circle containing the point on the outer contour of the groove is ФC2, with the center of the lamination body as the center, Ф-2 / 3×δ≤ФC2<Ф, where δ is the air gap width.
[0011] In some embodiments, the protrusion or groove is located between the d-axis and the q-axis.
[0012] In some embodiments, the protrusion or groove is formed by connecting multiple straight segments in sequence; or, the protrusion or groove is formed by connecting multiple arc segments in sequence; or, the protrusion or groove is formed by connecting multiple straight segments and arc segments in sequence.
[0013] In some embodiments, when the number of protrusions and / or grooves is even, the protrusions and / or grooves are evenly distributed on both sides of the d-axis.
[0014] According to another aspect of this application, a method for forming the above-mentioned rotor lamination is provided, comprising:
[0015] Stamping magnetic steel channels;
[0016] Stamping the inner circle of the rotor;
[0017] Stamping the outer circle of the rotor, wherein the outer circle of the rotor is discontinuously separated from the scrap material along the circumference, and the rotor laminations are connected to the scrap material at the protrusions and / or grooves.
[0018] Stamping is performed at the protrusions or grooves to disconnect the connection between the rotor lamination and the remaining material, thus forming the rotor lamination.
[0019] According to another aspect of this application, a rotor core is provided, comprising a plurality of rotor laminations stacked axially, the rotor laminations being the aforementioned rotor laminations.
[0020] According to another aspect of this application, a servo motor is provided, including a rotor core, which is the rotor core described above.
[0021] According to another aspect of this application, a robot is provided, including the rotor core described above or the servo motor described above.
[0022] Applying the technical solution of this application, the rotor lamination includes a lamination body with a rotor outer circle. In one application, the rotor outer circle of the lamination body has a groove recessed inward relative to the rotor outer circle and / or a protrusion protruding outward relative to the rotor outer circle. The groove and / or protrusion on the rotor outer circle of the rotor lamination allow for the formation of a connecting structure during the lamination process. This enables the lamination to be stamped in two steps, maintaining the connection at the groove or protrusion position while stamping the rotor outer circle. Only the structure of the rotor outer circle is stamped. The connecting effect of the groove or protrusion provides positioning for the stamping process, ensuring the machining and dimensional accuracy of the rotor outer circle. This prevents the dimensional accuracy from decreasing due to stamping stress, reduces distortion of the air gap magnetic flux density waveform, significantly reduces harmonic content, lowers motor cogging torque and torque pulsation, and improves robot positioning accuracy. Attached Figure Description
[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:
[0024] Figure 1 shows a schematic diagram of the structure of the motor in the related technology;
[0025] Figure 2 shows a schematic diagram of the rotor core structure of the related technology;
[0026] Figure 3 shows an enlarged schematic diagram of the structure at point A in Figure 2;
[0027] Figure 4 shows a schematic diagram of the stamping process of rotor laminations in the related technology;
[0028] Figure 5 shows the air gap magnetic flux density waveform of the motor when the rotor outer contour shape is not deformed in the related technology.
[0029] Figure 6 shows the air gap magnetic flux density waveform of the motor when the outer contour shape of the rotor is deformed in the related technology.
[0030] Figure 7 shows a schematic diagram of the structure of a rotor lamination according to an embodiment of this application;
[0031] Figure 8 shows an enlarged structural schematic diagram at point B in Figure 7;
[0032] Figure 9 shows a schematic diagram of the structure of a rotor lamination according to an embodiment of this application;
[0033] Figure 10 shows an enlarged structural schematic diagram at point C in Figure 9;
[0034] Figure 11 shows a schematic diagram of the stamping process of a rotor lamination according to an embodiment of this application;
[0035] Figure 12 shows a schematic diagram of the stamping process of a rotor lamination according to an embodiment of this application;
[0036] Figure 13 shows a dimensional structural diagram of a rotor lamination according to an embodiment of this application;
[0037] Figure 14 shows an enlarged structural schematic diagram at point D in Figure 13;
[0038] Figure 15 shows a dimensional structural diagram of a rotor lamination according to an embodiment of this application;
[0039] Figure 16 shows an enlarged structural schematic diagram at point E in Figure 15;
[0040] Figure 17 shows the curve of the effect of γ on the cogging torque of the motor.
[0041] Figure 18 shows the curve of the effect of α on the cogging torque of the motor;
[0042] Figure 19 shows the curve of the effect of ФC1 on the cogging torque of the motor.
[0043] Figure 20 shows the influence curve of ФC2 on the cogging torque of the motor.
[0044] Figure 21 shows a schematic diagram of the structure of a rotor lamination according to an embodiment of this application;
[0045] Figure 22 shows an enlarged structural schematic diagram at point G in Figure 21;
[0046] Figure 23 shows a schematic diagram of the structure of a rotor lamination according to an embodiment of this application;
[0047] Figure 24 shows an enlarged structural schematic diagram at point H in Figure 23;
[0048] Figure 25 shows a schematic diagram of the structure of a rotor lamination according to an embodiment of this application;
[0049] Figure 26 shows an enlarged structural schematic diagram at point F in Figure 25;
[0050] Figure 27 shows a schematic diagram of the rotor lamination structure according to an embodiment of this application; and
[0051] Figure 28 shows an enlarged structural schematic diagram of point I in Figure 27.
[0052] The above-mentioned figures include the following reference numerals: 1. Lamination body; 2. Rotor outer circle; 3. Groove; 4. Protrusion; 5. Rotor inner circle; 6. Magnet slot; 11. Air gap; 12. Stator core; 13. Coil winding; 14. Rotor core; 15. Magnet; 21. First arc segment; 22. Second arc segment; 23. Third arc segment. Detailed Implementation
[0053] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0054] As shown in Figures 1 to 3, the servo motor in the related technology includes a stator core 12 and a rotor core 14. The stator core 12 is sleeved on the outside of the rotor core 14, and an air gap 11 is formed between the stator core 12 and the rotor core 14. The radial width of the air gap 11 is δ. A stator slot is provided on the stator core 12, and a coil winding 13 is provided in the stator slot. A magnet slot 6 is provided on the rotor core 14, and a magnet 15 is provided in the magnet slot 6. Taking the outer contour of the rotor core 14 as a point on a circle and the center of the rotor core 14 as the center of the circle, the diameter of the largest circle formed is Ф. The outer contour of the rotor core 14 forms the rotor outer circle 2 of the rotor core 14. In order to make it easier to form a sine wave of air gap magnetic flux density, it is generally necessary to modify the structure of the rotor outer circle 2, as shown in Figure 3. In one pole, the rotor outer circle 2 includes a first arc segment 21, a second arc segment 12, and a third arc segment 13 connected in sequence. The three arc segments can adjust the air gap between the rotor core 14 and the stator core 12, thereby making it easier to form a sine wave of air gap magnetic flux density. In some embodiments, in one pole, the rotor outer circle 2 can also be a circular arc. The rotor core 14 also has a rotor inner circle 5.
[0055] When an electric motor is powered on, electrical energy is converted into a magnetic field, or armature magnetomotive force, through the stator windings. This magnetomotive force interacts with the permanent magnetomotive force generated by the permanent magnets on the rotor, producing an electromagnetic force that drives the rotor to rotate, thereby generating output torque and output power. Output torque is the motor's ability to produce rotational motion, while output power reflects the mechanical energy that the motor can output per unit time.
[0056] The rotor is the component that generates permanent magnet magnetomotive force. The design structure and dimensional accuracy of the rotor have a direct and significant impact on the electromagnetic performance of the motor. By designing the arrangement and shape of the magnets inside the rotor, the magnetic field distribution of the motor can be optimized, thereby affecting the motor's power density, efficiency, and cogging torque.
[0057] The radially embedded rotor core structure of the servo motor in the related technology is shown in Figures 2 and 3. The rotor core 14 consists of magnetic slots 6, an inner rotor circle 5, and an outer rotor circle 2. The outer contour of each rotor pole is composed of one or 3n (n is an integer) segments of arcs or straight lines. The rotor core 14 is formed by stacking rotor laminations made from multiple electromagnetic steel sheets through multiple stamping processes using a stamping die. The rotor lamination stamping process in the related technology is shown in Figure 4. Magnetic slots → inner rotor circle → outer rotor circle are stamped sequentially on the electromagnetic steel sheets. Finally, the rotor laminations are blanked into the stacking cavity for stacking to form the rotor core 14. The thickness of the rotor laminations is generally 0.2mm-1mm, which is relatively thin. During the die stamping process, the complex outer contour of the rotor laminations, due to the influence of stamping stress, will lead to poor dimensional accuracy in the final formed product. When the outer contour of the rotor laminations is the ideal design size, according to the principles of motor mechanics, the air gap magnetic flux density waveform is an ideal sine wave, as shown in Figure 5. When the stamping accuracy of the rotor's outer contour is poor and the dimensions deviate from the ideal value, the air gap magnetic flux density waveform will be greatly distorted, as shown in Figure 6. The harmonic content will increase significantly, which will eventually lead to an increase in the motor's cogging torque and torque pulsation, reducing the robot's positioning accuracy.
[0058] To solve the above problems, referring to Figures 7 to 28, according to the embodiments of this application, the rotor lamination includes a lamination body 1, the lamination body 1 having a rotor outer circle 2, and in one pole, the rotor outer circle 2 of the lamination body 1 is provided with a groove 3 that is recessed inward relative to the rotor outer circle 2 and / or a protrusion 4 that is protruding outward relative to the rotor outer circle 2.
[0059] The rotor lamination has grooves 3 and / or protrusions 4 on the outer diameter 2 of the rotor. The grooves 3 or protrusions 4 can form a connecting structure during the stamping process of the rotor lamination. This allows the stamping of the outer diameter 2 of the rotor lamination to be divided into two steps. While stamping the outer diameter 2 of the rotor, the connection is maintained at the position of the grooves 3 or protrusions 4. Only the structure of the outer diameter 2 of the rotor is stamped. At this time, the connecting effect of the grooves 3 or protrusions 4 can play a positioning role in the stamping process of the outer diameter 2 of the rotor. Therefore, it can ensure the machining accuracy and dimensional accuracy of the outer diameter 2 of the rotor, avoid the reduction of dimensional accuracy of the outer diameter 2 of the rotor due to the influence of stamping stress, reduce the distortion of the air gap magnetic flux density waveform, significantly reduce the harmonic content, reduce the motor cogging torque and torque pulsation, and improve the robot positioning accuracy.
[0060] Traditional motor rotor lamination forming processes typically involve a single-step forming process, where all outer contours of the lamination separate from the remaining material simultaneously during stamping. This method is prone to dimensional deviations due to uneven distribution of stamping stress. In this embodiment, by providing grooves 3 and / or protrusions 4 on the outer diameter 2 of the rotor, a step-by-step forming process can be adopted for the rotor lamination. First, the outer diameter of the rotor is separated from the remaining material, but by maintaining the connection between the rotor lamination and the remaining material at the protrusion or groove position, additional connection and positioning can be provided for the outer diameter of the rotor during the forming process, reducing deformation during stamping and thus improving the dimensional accuracy of the outer diameter of the rotor.
[0061] Maintaining the connection between the rotor lamination and the remaining material during the initial stage of rotor lamination forming, especially at locations with protrusions or grooves, ensures greater stability of the lamination during stamping. This reduces dimensional fluctuations in the rotor's outer diameter caused by variations in stamping pressure, thereby improving the overall stability of the processing. By retaining connection points between the rotor's outer diameter 2 and the remaining material—namely, at the locations of protrusions 4 or grooves 3—stress concentration-induced lamination breakage or deformation can be effectively reduced, thereby increasing yield and reducing scrap and reprocessing costs.
[0062] In one embodiment, the protrusion 4 or the groove 3 has two endpoints at both ends along the circumferential direction, and the included angle formed by the line connecting the two endpoints and the center of the lamination body 1 is γ, 1°≤γ≤70 / P°, where P is the number of rotor poles.
[0063] In one embodiment, the protrusion 4 or the groove 3 is located between the d-axis and the q-axis.
[0064] To optimize the cogging torque of the motor, this application designs and studies the structural size and position of the protrusion 4 and the groove 3. Figures 13 to 15 are detailed diagrams illustrating the size and position of the protrusion or groove structure of the rotor lamination in an embodiment of this application. According to the principles of motor mechanics, under one pole, the centerline of a single magnet slot 6 is the d-axis of the rotor structure, and in two adjacent poles, the centerline of the magnet slot 6 is the q-axis of the rotor structure. In the embodiment of this application, the protrusion and groove structure is located between the d-axis and the q-axis, and does not cross the d-axis and the q-axis; that is, neither the d-axis nor the q-axis passes through the protrusion or groove. Between two adjacent d-axis, there is one protrusion 4 or groove 3, or two protrusions 4 or grooves 3. If the number of rotor poles is P, then the number of protrusions 4 or grooves 3 is P or 2P. When there are two protrusions 4 or grooves 3, they can be symmetrical about the d-axis or not. The maximum angle formed by connecting the points on the outer contour of protrusion 4 or groove 3 to the center point of the rotor lamination is γ. Research has shown that γ affects the motor cogging torque; the larger γ is, the greater the motor cogging torque, and the worse the positioning accuracy of the robot using this motor. γ also cannot be too small. If γ is too small, the width of protrusion 4 or groove 3 in the circumferential direction will be too small, failing to provide effective connection and positioning during the rotor lamination stamping process. The qualitative relationship between γ and motor cogging torque is shown in Figure 17. The motor performance is optimal when 1° < γ ≤ 70 / P°.
[0065] In one embodiment, the angle between the line connecting the end point of the protrusion 4 or groove 3 near the d-axis and the center of the lamination body 1 and the d-axis is α, where 20° / P≤α≤80° / P, and P is the number of rotor poles.
[0066] α is the minimum angle formed between the line connecting the point on the outer contour of protrusion 4 or groove 3 and the center point of the rotor lamination and the d-axis. Research has shown that α also affects the motor cogging torque. The motor cogging torque performance is optimal when 20 / P° ≤ α ≤ 80 / P°, resulting in the best positioning accuracy for the robot using this motor. The qualitative relationship between α and the motor cogging torque is shown in Figure 18.
[0067] In one embodiment, the diameter of the outer circle 2 of the rotor is Ф. When the protrusion 4 is provided on the outer circle 2 of the rotor, the maximum diameter of the circle containing the point on the outer contour of the protrusion 4 is ФC1, with the center of the lamination body 1 as the center. Ф<ФC1≤Ф+2 / 3×δ, where δ is the air gap width. Ф<ФC1≤Ф+2 / 3×δ, where δ is the air gap width.
[0068] When the connecting structure on the outer circle of the rotor is a raised structure, ФC1 is a point on the outer contour of the raised structure, and the center point of the rotor lamination is the diameter of the largest circle formed by the center. The larger ФC1 is, the greater the distance between the outer contour of the raised structure and the outer circle 2 of the rotor. This change causes a greater change in the size of the air gap in the circumferential direction of the motor. According to the principles of motors, the change in the circumferential distribution of the motor air gap directly causes a change in the motor cogging torque. The greater the deviation of the outer contour of the raised structure from the outer circle of the rotor, the worse the uniformity of the motor air gap, and the greater the motor cogging torque.
[0069] Further research revealed that when the connection structure is a protrusion, if ФC1 and the outer contour of the rotor's outer circle are taken as points on the circle, and the outer contour of the rotor's outer circle does not consider the protrusion structure, the diameter Ф of the largest circle formed with the rotor center as the center and the air gap width δ satisfy the following relationship: Ф<ФC1≤Ф+2 / 3×δ. At this time, the motor's cogging torque performance is optimal, and the robot using this motor has the best positioning accuracy, as shown in Figure 19.
[0070] When a groove 3 is provided on the outer circle 2 of the rotor, the minimum diameter of the circle containing the point on the outer contour of the groove 3 is ФC2, with the center of the lamination body 1 as the center. Ф-2 / 3×δ≤ФC2<Ф, where δ is the air gap width.
[0071] When the connecting structure on the outer circle of the rotor is a groove structure, ФC2 is a point on the outer contour of the polygonal groove structure, and the center point of the rotor lamination is the diameter of the smallest circle formed by the center. The smaller ФC2 is, the greater the distance between the outer contour of the groove structure and the outer circle of the rotor. This change causes a greater change in the size of the air gap in the circumferential direction of the motor. According to the principles of motors, the change in the circumferential distribution of the motor air gap directly causes a change in the motor cogging torque. The greater the distance between the outer contour of the groove structure and the outer circle of the rotor, the worse the uniformity of the motor air gap, and the greater the motor cogging torque.
[0072] Further research revealed that when the connection structure is groove 3, and the outer contour of ФC2 and the outer circle 2 of the rotor are taken as points on the circle, without considering the groove structure, the diameter Ф of the largest circle formed by the rotor center and the air gap length δ satisfy the following relationship: Ф-2 / 3×δ≤ФC2<Ф. The motor cogging torque performance is optimal, and the robot using this motor has the best positioning accuracy, as shown in Figure 20.
[0073] In one embodiment, when the outer contour of the rotor lamination has 1 or 3n (n is an integer) segments of circular arcs or straight lines, and the connecting structure is a raised structure, the motor cogging torque performance is optimal when 0°<γ≤70 / P°, 20 / P°≤α≤80 / P°, and Ф<ФC≤Ф+2 / 3×δ, resulting in the highest positioning accuracy for the robot using this motor. When the connecting structure is a recessed structure, the motor cogging torque performance is optimal when 0°<γ≤70 / P°, 20 / P°≤α≤80 / P°, and Ф-2 / 3×δ≤ФC<Ф, resulting in the highest positioning accuracy for the robot using this motor.
[0074] By precisely controlling the position and shape of the connection structure—specifically the γ and α angles of the protrusions or grooves, and the relationship between the ФC diameter, the rotor outer contour diameter Ф, and the air gap length δ—the magnetic flux density distribution in the motor's air gap can be optimized. This optimization is crucial for improving the motor's efficiency and power density, while also reducing the distortion of the magnetic flux density waveform, which is beneficial for forming a smooth sinusoidal waveform.
[0075] Cogging torque is the additional torque generated by the interaction between the stator and rotor teeth of a motor when no external force is applied. By limiting the angles γ and α within a specific range, the cogging torque can be effectively reduced, especially in the case of a raised structure where 0°<γ≤70 / P° and 20 / P°≤α≤80 / P°, and in the case of a recessed structure where 0°<γ≤70 / P° and 20 / P°≤α≤80 / P°. In these cases, the cogging torque of the motor can be minimized, resulting in smoother motor operation and reduced unnecessary energy loss.
[0076] The cogging torque and torque ripple of the motor directly affect the positioning accuracy of the robot. When using the rotor laminations of this embodiment, the significant reduction in cogging torque and torque ripple enables the robot to achieve higher positioning accuracy and dynamic response performance when performing precision positioning tasks. By optimizing the relationship between the diameter of the circle containing the protrusion or groove and Ф and δ, efficient material utilization can be achieved. In the protrusion structure, the condition Ф<ФC≤Ф+2 / 3δ ensures that the size of the protrusion structure is appropriate, neither too large to increase material waste nor too small to affect performance. In the groove structure, the condition Ф-2 / 3δ≤ФC<Ф similarly optimizes the groove size, thereby achieving reasonable cost control while ensuring motor performance.
[0077] In one embodiment, the protrusion 4 or the groove 3 is formed by connecting multiple straight line segments in sequence to form a polygonal structure.
[0078] In one embodiment, the protrusion 4 or the groove 3 is formed by connecting multiple arc segments in sequence.
[0079] In one embodiment, the protrusion 4 or the groove 3 is formed by sequentially connecting multiple straight segments and arc segments.
[0080] In one embodiment, the protrusion 4 or the groove 3 is an arc structure.
[0081] In one embodiment, the protrusion 4 or the groove 3 is a trapezoidal structure.
[0082] In one embodiment, the protrusion 4 or the groove 3 is a rectangular structure.
[0083] In one embodiment, the outer circle 2 of the rotor includes an arc or a straight line, or a combination of an arc and a straight line. The end of the protrusion 4 or the groove 3 may not be directly connected to the arc segment of the outer circle of the rotor, but may be connected to the arc segment of the outer circle of the rotor through a straight line segment.
[0084] In one embodiment, when the number of protrusions 4 and / or grooves 3 is even, the protrusions 4 and / or grooves 3 are evenly distributed on both sides of the d-axis.
[0085] According to an embodiment of this application, a method for forming the above-mentioned rotor lamination includes:
[0086] Stamping of magnetic steel channel 6;
[0087] Stamping the inner diameter of the rotor to 5;
[0088] Stamping the outer circle 2 of the rotor, wherein the outer circle 2 of the rotor is intermittently separated from the scrap material along the circumference, and the rotor laminations are connected to the scrap material at the protrusions 4 and / or grooves 3.
[0089] Stamping is performed at protrusion 4 or groove 3 to disconnect the connection between the rotor lamination and the remaining material, thus forming the rotor lamination.
[0090] The aforementioned surplus material refers to the portion of the blank remaining after the rotor laminations have been stamped.
[0091] In this embodiment, the outer contour of each pole of the rotor lamination has 1 or 3n (n is an integer) segments of arcs or straight lines, as well as protrusions or grooves. Rotor laminations with protrusions are shown in Figures 7 and 8, and rotor laminations with grooves are shown in Figures 9 and 10. During die stamping, the outer contour stamping process can be divided into two steps: first, the outer contour arc of the rotor outer circle 2 is stamped; second, the protrusions or grooves are stamped. During the stamping of the outer contour arc of the rotor outer circle 2, the rotor lamination is still connected to the blank through the structure at the protrusion 4 or groove 3. By using a step-by-step outer contour stamping method, in the first step of stamping the rotor outer circle 2, since some of the outer contour structure of the rotor lamination is still attached to the blank such as the electromagnetic steel sheet, the stability is better. The dimensional accuracy of the outer contour arc and other parts of the rotor outer circle 2 stamped in the first step is significantly higher than that of the outer contour of a rotor outer circle with a traditional structure. The second step only requires stamping the remaining connecting sections to complete the stamping of the complete rotor lamination. Since there are fewer remaining connecting sections, the stamping stress is smaller, and the accuracy of the stamped protrusions or grooves is also significantly higher than that of the outer contour dimensions of the traditional rotor structure. The stamping process flow diagram of the rotor lamination in this embodiment is shown in Figures 11 and 12.
[0092] According to an embodiment of this application, the rotor core includes a plurality of rotor laminations stacked axially, the rotor laminations being the aforementioned rotor laminations.
[0093] According to an embodiment of this application, the servo motor includes a rotor core, which is the rotor core described above.
[0094] According to embodiments of this application, the robot includes the rotor core described above or the servo motor described above.
[0095] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0096] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.
[0097] The above are merely some embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A rotor lamination, characterized by Includes a lamination body (1), the lamination body (1) having a rotor outer circle (2), and at one pole, the rotor outer circle (2) of the lamination body (1) is provided with a groove (3) that is recessed inward relative to the rotor outer circle (2) and / or a protrusion (4) that is protruding outward relative to the rotor outer circle (2).
2. The rotor lamination of claim 1, wherein, The protrusion (4) or the groove (3) has two endpoints at both ends along the circumferential direction. The angle formed by the line connecting the two endpoints and the center of the lamination body (1) is γ, 1°≤γ≤70 / P°, where P is the number of rotor poles.
3. The rotor lamination of claim 1, wherein, The angle between the line connecting the end point of the protrusion (4) or the groove (3) near the d-axis and the center of the lamination body (1) and the d-axis is α, where 20° / P≤α≤80° / P, and P is the number of rotor poles.
4. The rotor lamination of claim 1, wherein, The diameter of the outer circle (2) of the rotor is Ф. When the protrusion (4) is provided on the outer circle (2) of the rotor, the maximum diameter of the circle containing the point on the outer contour of the protrusion (4) is ФC1, with the center of the lamination body (1) as the center, Ф<ФC1≤Ф+2 / 3×δ, where δ is the air gap width. When the groove (3) is provided on the outer circle (2) of the rotor, the minimum diameter of the circle containing the point on the outer contour of the groove (3) is ФC2, with the center of the lamination body (1) as the center, Ф-2 / 3×δ≤ФC2<Ф, where δ is the air gap width.
5. The rotor lamination of claim 1, wherein, The protrusion (4) or the groove (3) is located between the d-axis and the q-axis.
6. The rotor lamination of claim 1, wherein, The protrusion (4) or the groove (3) is formed by connecting multiple straight segments in sequence; or, the protrusion (4) or the groove (3) is formed by connecting multiple arc segments in sequence; or, the protrusion (4) or the groove (3) is formed by connecting multiple straight segments and arc segments in sequence.
7. The rotor lamination of claim 1, wherein, When the number of the protrusions (4) and / or the grooves (3) is an even number, the protrusions (4) and / or the grooves (3) are evenly distributed on both sides of the d-axis.
8. A method of forming a rotor lamination as claimed in any one of claims 1 to 7, characterised in that, include: Stamping magnetic steel groove (6); Stamp the inner circle of the rotor (5); Stamping the outer circle (2) of the rotor, wherein the outer circle (2) of the rotor is discontinuously separated from the scrap in the circumferential direction, and the rotor laminations are connected to the scrap at the protrusions (4) and / or grooves (3); Stamping is performed at the protrusion (4) or groove (3) to disconnect the connection between the rotor lamination and the remaining material, thus forming the rotor lamination.
9. A rotor core comprising a plurality of rotor laminations stacked in an axial direction, characterized by, The rotor lamination is the rotor lamination as described in any one of claims 1 to 7.
10. A servo motor comprising a rotor core, characterized by The rotor core is the rotor core as described in claim 9.
11. A robot, characterized in that It includes the rotor core as described in claim 9 or the servo motor as described in claim 10.