A radial skewed slot rotor and its applied motor

Abstract

The present invention discloses a radial skewed slot rotor and a motor using the same. The motor using the radial skewed slot rotor includes a radial skewed slot rotor, which includes a rotating shaft, multiple rotor punchings, and guide bars. The rotor punchings are mainly formed by coaxially stacking multiple rotor punchings, wherein an axial hole is opened at the axial position of the rotor punchings, and the position of the rotor slots remains unchanged. The center lines of the outer circle rotor slots are tilted at a certain angle along the radial direction of the rotor punchings to form inclined rotating slots, and the multiple rotating slots are evenly distributed along the circumference. The radial skewed slot rotor and the motor using the same according to the present invention can be directly applied to existing asynchronous motors. Compared with the currently widely used axial skewed slot rotor motor, the manufactured radial skewed slot rotor motor has a reduced equivalent slot depth and equivalent guide bar length, resulting in a reduced total leakage reactance, reducing losses and the magnitude of reactive current in the rotor, thereby achieving the effect of improving efficiency and power factor and increasing overload capacity.

Description

Technical Field

[0001] The present invention belongs to the field of motor design, and in particular relates to a radial skewed slot rotor and a motor using the same. Background Art

[0002] At present, asynchronous motors are mainly composed of two parts: the stator and the rotor. The conversion of electromechanical energy can be achieved through the electromagnetic relationship between the two.

[0003] The rotors of existing asynchronous motors are mostly axially skewed slot rotors. The existing patent with reference number CN 211508742U discloses an asynchronous motor with an axially skewed slot rotor. That is, the rotor slots are twisted at an angle relative to the stator slots along the axial direction, which causes the rotor guide bar slots or cast aluminum slots of the motor to be non-straight. While the fundamental wave skew slot coefficient remains basically unchanged, the tooth harmonic skew slot coefficient is greatly reduced, thereby reducing the air gap harmonics and achieving the effect of reducing motor noise. This type of axially skewed slot motor has some defects. Since the guide bars are twisted at an angle to increase their total length, it has an additional skewed slot leakage reactance compared to straight slots, while other leakage reactances do not change much. This skewed slot leakage reactance will reduce the efficiency of the motor, reduce the power factor, and deteriorate the overload capacity, thereby affecting the overall performance of the motor. Summary of the Invention

[0004] In order to solve the technical problems existing in the background technology, the present invention proposes a radial skewed slot rotor and a motor using the same.

[0005] The present invention proposes a radial skewed slot rotor, which forms an inclined slot by twisting the center line of the rotor slot on the rotor punching by a certain angle along the radial direction of the rotor punching when manufacturing the motor rotor. The twisting angle is defined as the slot inclination angle, which is expressed by the angle between the center line of the inclined slot and the line connecting the point of the inclined slot center line farthest from the center of the rotor punching and the center point of the rotor. There are multiple inclined slots, and the multiple inclined slots are evenly distributed along the circumference of the rotor punching. There are multiple notches on the side of the rotor punching, and one notch is connected to one inclined slot. There are multiple rotor punchings, and the multiple rotor punchings are directly stacked, and the inclined slots of any two adjacent rotor punchings are opposite, so as to manufacture a radial skewed slot rotor, which can be directly applied to existing motors to form a new motor. Compared with the currently widely used axial skewed slot rotor motor, the manufactured radial skewed slot rotor motor has a smaller equivalent slot depth and an equivalent conductor bar length, resulting in a smaller total leakage reactance, reducing the loss and the magnitude of the reactive current in the rotor, thereby achieving the effect of improving efficiency and power factor and increasing overload capacity.

[0006] As a further optimized solution of the present invention, the slot inclination angle is an acute angle, and the motor performance is optimal when the slot inclination angle is 25°.

[0007] In some embodiments, the notch is twisted along with the groove to form a twisted notch, and the direction of the notch is inclined to the radial direction.

[0008] In some embodiments, the notch does not twist with the slot, and the direction of the notch is along the radial direction of the rotor sheet.

[0009] A motor using a radial skewed slot rotor comprises the above-mentioned skewed slot rotor and an existing stator and a casing.

[0010] In the present invention, the proposed radial skewed slot rotor and the motor using the same have the following beneficial effects:

[0011] 1. The motor of the present invention uses a radial skewed slot rotor to reduce the skew slot leakage reactance and slot leakage reactance, thereby effectively reducing the total leakage reactance value. As a result, the motor has higher efficiency and power factor, as well as better overload capacity, compared to motors with axial skewed slot rotors.

[0012] 2. Compared with straight slot motors, it has better torque pulsation and vibration noise, thus having better overall motor performance.

[0013] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of the radial skewed slot rotor of the present invention;

[0015] Figure 2 This is a schematic diagram of the cross-sectional structure of the radial skewed slot rotor of the present invention;

[0016] Figure 3 This is a schematic diagram of a skewed slot rotor in the present invention being applied to a straight slot stator motor;

[0017] Figure 4 This is a cross-sectional schematic diagram of a skewed slot rotor in the present invention applied to a straight slot stator motor;

[0018] Figure 5 This is a schematic diagram of a parallel slot structure for the slots of the rotor punchings according to the first embodiment of the present invention;

[0019] Figure 6 This is a schematic diagram of a twisted notch structure for the notches of the rotor punchings according to the second embodiment of the present invention;

[0020] Figure 7 The power factor changes of the motor model in Example 1 of the present invention, with a load torque of 70 N·m, are shown for straight slots, axially skewed slots, and radially skewed slots with different slot inclination angles.

[0021] Figure 8The torque ripple changes of the motor model in Example 1 of the present invention, with a load torque of 70 N·m, are shown for straight slots, axially skewed slots, and radially skewed slots with different slot inclination angles.

[0022] Figure 9 The efficiency changes of straight slot, axial skew slot, and radial skew slot motors with different slot inclination angles are shown in Figure 1.

[0023] Figure 10 The efficiency changes of straight slot, axial skew slot, and radial skew slot motors with different slot inclination angles are shown in Figure 1, when a load torque of 140 N·m is applied to the motor model in Example 1 of the present invention.

[0024] Figure 11 The power factor changes of the motor model in Example 1 of the present invention, with a load torque of 140 N·m, are shown for straight slots, axially skewed slots, and radially skewed slots with different slot inclination angles.

[0025] Figure 12 The maximum torque variation of the straight slot, axial skew slot, and radial skew slot motors with different slot inclination angles in Example 1 of the present invention is shown in FIG.

[0026] Figure 13 The power factor changes of the motor model in Example 2 of the present invention with a load torque of 70 N·m, straight slot, axial skew slot, and radial skew slot motors with different slot inclination angles are shown.

[0027] Figure 14 The torque ripple changes of the motor model in Example 2 of the present invention, with a load torque of 70 N·m, are shown for straight slots, axially skewed slots, and radially skewed slots with different slot inclination angles.

[0028] Figure 15 The efficiency changes of straight slot, axial skew slot, and radial skew slot motors with different slot inclination angles are shown in Figure 2 of the present invention when a load torque of 70 N·m is applied to the motor model in Example 2.

[0029] Figure 16 The efficiency changes of straight slot, axial skew slot, and radial skew slot motors with different slot inclination angles are shown in Figure 2 when a load torque of 140 N·m is applied to the motor model in Example 2 of the present invention.

[0030] Figure 17 The power factor changes of the motor model in Example 1 of the present invention, with a load torque of 140 N·m, are shown for straight slots, axially skewed slots, and radially skewed slots with different slot inclination angles.

[0031] Figure 18 The maximum torque variation of the straight slot, axial skew slot, and radial skew slot motors with different slot inclination angles in Example 2 of the present invention is shown in FIG.

[0032] In the figure: 1-rotor shaft; 2-rotor punching; 3-inclined rotor slot; 4-slot; 7-stator; 8-stator slot. DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention, and are not to be construed as limiting the present invention.

[0034] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0036] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0037] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0038] Example 1

[0039] like Figure 1-5 As shown, a motor includes a radial skewed slot rotor, the radial skewed slot rotor includes a rotor punching. An asynchronous motor rotor punching structure is as shown in FIG. Figure 1-2 As shown, the rotor punching includes a rotor punching 2, and an inclined rotation groove 3 is opened on the rotor punching 2. The center line of the inclined rotation groove 3 intersects with the diameter of any rotor punching 2. There are 26 inclined rotation grooves 3, and the 26 inclined rotation grooves 3 are evenly distributed along the circumference of the rotor punching 2. As needed, the inclined grooves 3 can be provided with other numbers of rotor punching grooves 3, such as 18, 24 or 36, etc. The side of the rotor punching 2 is provided with multiple notches 4, one notch 4 is connected to one inclined rotation groove 3, and the notches 4 are parallel notches (that is, the notches 4 are not twisted, and the notches 4 are radially parallel to the rotor punching 2 as shown in FIG. Figure 5 The rotor punchings 2 are provided with a plurality of rotor punchings 2, and the plurality of rotor punchings 2 are coaxially stacked to form a rotor body, and the inclined rotation slots 3 of any two adjacent rotor punchings 2 are opposite.

[0040] The angle between the center line of the inclined rotating slot 3 and the line connecting the point on the center line of the inclined rotating slot 3 farthest from the center of the rotor punching 2 and the center point of the rotor is an acute angle, and this angle is defined as the slot inclination angle, as shown by α in the figure; the motor also includes a rotating shaft 1 and a stator 7, the rotating shaft is fixed to the middle of the rotor, the stator 7 is mounted on the outside of the rotor body, and a stator slot 8 is opened on the stator, and the stator slot 8 is a slot type of the existing technology.

[0041] Using simulation software, the authors considered that rotor slot twisting can cause stator-rotor harmonic coupling, and that excessive slot inclination can lead to excessive magnetic flux density between the ends of adjacent motor bars, causing local oversaturation and heating. Furthermore, considering the impact of radial skewed rotors on motor performance, slot inclinations were set between 5° and 30°. Taking 5°, 10°, 15°, 20°, 25°, and 30° as examples, when current flows through the stator coils to generate a magnetic field, an electromotive force is induced in the energized bars of the radial skewed rotor, generating an Ampere force. Because the rotor slots in the radial skewed rotor are twisted by an angle, the electromotive forces induced by higher harmonics in the bars cancel each other out, weakening the higher harmonics and making the air gap magnetic field waveform closer to a sine wave, resulting in higher motor efficiency and power factor. The following is the simulation process for a radial skewed rotor motor.

[0042] Motor simulation parameters: stator outer diameter 260mm, stator inner diameter 170mm, rotor outer diameter 169mm, rotor inner diameter 60mm, motor length 155mm, stator and rotor lamination material D23_50, slot ratio 36 / 26, excitation source 50Hz 380V voltage source; motor rated power 11kW. Using the existing parameters, a motor model was established, and simulations were performed for different slot angles.

[0043] Then, a load torque of 70 N·m was applied to the established motor model to observe the motor performance, namely torque ripple, efficiency, and power factor, for straight slots, axially skewed slots, and radially skewed slots with different slot inclination angles.

[0044] Through simulation, a series of data were obtained and compared, such as Figure 7-9 As shown in the figure, this analysis and comparison shows that while axial skewed rotor motors have lower torque pulsation and more stable output torque, their efficiency and power factor are lower. Radial skewed rotor motors, on the other hand, have higher efficiency and power factor than axial skewed rotor motors and lower torque pulsation compared to conventional straight-slot motors. Furthermore, torque pulsation is minimized when the slot angle is 25°.

[0045] Then, a 140 N·m load torque was applied for simulation, and the efficiency and power factor were observed. The results are as follows: Figure 10-11 shown.

[0046] When the motor is nearly double overloaded, the radial skew rotor motor has lower losses and better efficiency than straight and axial skew rotors. As the slot angle increases, the losses further decrease, further improving the efficiency. Similarly, the power factor is also higher than those of straight and axial skew rotors. Regarding torque ripple, when the slot angle is around 25°, the radial skew rotor motor has lower torque ripple than the axial skew rotor motor, resulting in higher efficiency and power factor, achieving excellent motor performance.

[0047] From the above, we can see that the efficiency and power factor of radial skewed slot rotor motors are roughly the same as those of straight slot motors, and higher than those of axial skewed slot rotor motors. Therefore, we can conclude that the efficiency and power factor of radial skewed slot rotor motors are higher than those of axial skewed slot rotor motors.

[0048] The maximum torque that the motor can bear without speed drop is taken as the maximum torque value of the motor. Through a series of simulations, the simulation results are as follows: Figure 12 shown.

[0049] As can be seen from the figure, the maximum torque value of the radial skewed slot rotor motor is basically higher than that of the straight slot motor and the axial skewed slot rotor motor, indicating that the motor can load a larger torque and has a better overload capacity.

[0050] In summary, under rated load and overload conditions, radial skewed rotor motors effectively reduce torque pulsation, and their efficiency and power factor are superior to those of axial skewed rotor motors. They also have good overload capacity. Taking these points into account, the motor's overall performance is best when the slot angle is 25° and the slots 4 are parallel (i.e., the slots 4 are not twisted and run radially along the rotor laminations 2).

[0051] Example 2

[0052] like Figure 6 As shown, in this embodiment, the motor parameters, simulation process and slot type are the same as those in the first embodiment, only the parallel slot 4 in the rotor slot torsion process is changed to a torsion slot 4, and the torsion direction and angle of the slot 4 are the same as those of the inclined rotating slot 3, and the motor is simulated.

[0053] A load torque of 70 N·m was applied to the established motor model, and the motor performance, namely torque ripple, efficiency, and power factor, was observed for straight slots, axial skewed slots, and radial skewed slots with different torsion angles.

[0054] Through simulation, the simulation results are as follows Figure 13-15 The data is shown in Figure 2. This analysis and comparison reveals that while axial skewed rotor motors exhibit lower torque pulsation and more stable output torque, they also exhibit lower efficiency and power factor. Radial skewed rotor motors, on the other hand, have higher efficiency and power factor than axial skewed rotor motors and lower torque pulsation compared to conventional straight-slot motors. Furthermore, torque pulsation is minimized at a slot angle of 25°.

[0055] Then, we simulated the load torque of 140 N·m and observed the efficiency and power factor. The results are as follows: Figure 16-17 shown.

[0056] pass Figure 16-17When the motor is nearly double overloaded, the radial skew rotor motor has lower losses and better efficiency than straight and axial skew rotors. As the slot angle increases, the losses further decrease, further improving the efficiency. Similarly, the power factor is also higher than those of straight and axial skew rotors. Regarding torque ripple, when the slot angle is around 25°, the radial skew rotor motor has lower torque ripple than the axial skew rotor motor, resulting in higher efficiency and power factor, achieving excellent motor performance.

[0057] From the above, we can see that the efficiency and power factor of radial skewed slot rotor motors are roughly the same as those of straight slot motors, and higher than those of axial skewed slot rotor motors. Therefore, we can conclude that the efficiency and power factor of radial skewed slot rotor motors are higher than those of axial skewed slot rotor motors.

[0058] The maximum torque that the motor can bear without speed drop is taken as the maximum torque value of the motor. Through a series of simulations, the maximum torque of the motor is obtained. Figure 18 .

[0059] from Figure 18 It can be seen from the figure that the maximum torque value of the radial skewed slot rotor motor is basically higher than that of the straight slot motor and the axial skewed slot rotor motor, indicating that the motor can load a larger torque and has a better overload capacity.

[0060] This demonstrates that, under rated load and overload conditions, radial skew rotor motors effectively reduce torque ripple, and offer superior efficiency and power factor compared to axial skew rotor motors. They also possess excellent overload capacity. Taking all of these points into account, the motor's overall performance is superior when the slot angle is 25° and Slot 4 is a torsional slot.

[0061] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A radial skewed slot rotor, characterized in that: It includes rotor laminations, including: The rotor punching is provided with an inclined groove, the center line of which intersects with the diameter of any rotor punching. There are multiple inclined grooves, and the multiple inclined grooves are evenly distributed along the circumference of the rotor punching. The side of the rotor punching is provided with multiple notches, and each notch is connected to one inclined groove. There are multiple rotor punchings, which are coaxially stacked, and the inclined grooves of any two adjacent rotor punchings are opposite to each other; The angle between the centerline of the inclined groove and the line connecting the point on the centerline of the inclined groove farthest from the center of the rotor punching and the center point of the rotor is 25°; The notch and the inclined groove are twisted in the same direction and at the same angle.

2. A motor using a radial skewed slot rotor, characterized in that: The radially skewed slot rotor according to claim 1.

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