Electric machines and vehicles

Abstract

The utility model discloses a kind of motor and vehicle, it is related to the technical field of vehicle, wherein, motor includes stator and rotor, rotor rotates and is located in stator, rotor includes the multiple rotor punching sheet of laminated arrangement, multiple groups of magnetic steel groove are equipped on rotor punching sheet, each group of magnetic steel groove includes first magnetic steel groove, second magnetic steel groove, third magnetic steel groove and fourth magnetic steel groove, first magnetic steel groove and second magnetic steel groove are symmetrically arranged in the radial direction of rotor, third magnetic steel groove and fourth magnetic steel groove are symmetrically arranged in the radial direction of rotor, third magnetic steel groove and fourth magnetic steel groove are all located the outside of first magnetic steel groove and second magnetic steel groove, the included angle between first magnetic steel groove and second magnetic steel groove is α, the included angle between third magnetic steel groove and fourth magnetic steel groove is β, 35 °≤β-α≤50 °.The technical scheme provided by the utility model improves the torque density of motor.

Description

Technical Field

[0001] This utility model relates to the technical field of vehicles, and in particular to an electric motor and a vehicle. Background Technology

[0002] With the advancement of the "dual carbon" goals, the penetration rate of new energy commercial vehicles is rapidly increasing. The heavy loads, frequent uphill climbing, and high-speed highway operation characteristics of commercial vehicles pose challenges to the performance of motors in new energy commercial vehicles. High speed, high efficiency, and high power density are essential performance characteristics for drive motors in new energy commercial vehicles.

[0003] The existing technical solution uses two magnetic steel slots for each magnetic pole, and three permanent magnets in each magnetic steel slot. The included angle between the corresponding permanent magnets in each magnetic steel slot is also set. However, this motor design method has limited effect on reducing torque ripple and increasing torque density, and cannot meet the current requirements. Utility Model Content

[0004] The main objective of this invention is to provide an electric motor and vehicle that aim to improve the torque density of the motor.

[0005] To achieve the above objectives, the motor proposed in this utility model includes: Stator; and The rotor is rotatably mounted within the stator. The rotor includes multiple rotor laminations stacked on top of each other. Each rotor lamination has multiple sets of magnet slots. Each set of magnet slots includes a first magnet slot, a second magnet slot, a third magnet slot, and a fourth magnet slot. The first and second magnet slots are symmetrically arranged in the radial direction of the rotor. The third and fourth magnet slots are also symmetrically arranged in the radial direction of the rotor. The third and fourth magnet slots are located outside the first and second magnet slots. The included angle between the first and second magnet slots is α, and the included angle between the third and fourth magnet slots is β, where 35°≤β-α≤50°.

[0006] In one embodiment, 90°≤α≤105°, 135°≤β≤145°.

[0007] In one embodiment, 97.4°≤α≤97.9°, 140.15°≤β≤140.65°.

[0008] In one embodiment, the outer peripheral wall of the rotor lamination is provided with a magnetic adjustment groove, and each group of magnetic slots is provided with two magnetic adjustment grooves, which are symmetrically arranged in the radial direction of the rotor.

[0009] In one embodiment, the magnetic adjustment slot is elliptical in shape.

[0010] In one embodiment, the length of the long half-axis of the magnetic adjustment groove is a, the length of the short half-axis of the magnetic adjustment groove is b, and 2.9 ≤ a / b ≤ 3.1.

[0011] In one embodiment, the centers of the two elliptical grooves in the same group are the first elliptical center and the second elliptical center, respectively. The circle passing through the first elliptical center and the second elliptical center is an auxiliary circle with a radius of r, 70mm≤r≤80mm. The angle between the line connecting the first elliptical center and the center of the auxiliary circle and the line connecting the second elliptical center and the center of the auxiliary circle is γ, 7.9°≤γ≤8.1°.

[0012] In one embodiment, the plurality of rotor laminations includes at least two sets of rotor laminations, each set of rotor laminations includes three stacks of rotor laminations, and each stack of rotor laminations includes a plurality of rotor laminations stacked together. The angle difference between the positions of the corresponding magnet slots on two adjacent stacks of rotor laminations in the same set of rotor laminations is θ, where 2.4°≤θ≤2.6°. The deflection directions of the corresponding magnet slots on two adjacent sets of rotor laminations are opposite, and the positions of the corresponding magnet slots on two adjacent stacks of rotor laminations in two adjacent sets of rotor laminations are the same.

[0013] In one embodiment, the rotor lamination is provided with a first weight reduction hole, and each group of magnet slots corresponds to one first weight reduction hole. The first weight reduction hole is located between the first magnet slot and the second magnet slot in the same group of magnet slots.

[0014] In one embodiment, the rotor lamination is provided with a second weight reduction hole, which is located between the first magnet slot of a set of magnet slots and the second magnet slot of an adjacent set of magnet slots.

[0015] In one embodiment, the stator is provided with stator slots, the number of stator slots is 54, and the number of poles of the rotor is 6.

[0016] In one embodiment, the motor further includes a permanent magnet, and the magnetic slot includes a main body section and two magnetic adjustment sections connected to each other. The two magnetic adjustment sections are respectively disposed at both ends of the main body section. The main body section is adapted to accommodate the permanent magnet with a rectangular cross-section, and the magnetic adjustment sections are irregularly shaped.

[0017] In one embodiment, the outer peripheral wall of the stator is provided with protrusions; and / or The stator has a welding groove on its outer peripheral wall; and / or The rotor laminations are provided with snap points.

[0018] This utility model also proposes a vehicle that includes the aforementioned motor.

[0019] In this invention, each set of magnet slots is arranged as a first magnet slot, a second magnet slot, a third magnet slot, and a fourth magnet slot, i.e., each set of magnet slots is arranged in a double V-shape. Furthermore, the included angle between the first and second magnet slots is α, and the included angle between the third and fourth magnet slots is β, where 35°≤β-α≤50°. The third and fourth magnet slots widen the magnetic path along the q-axis, allowing the magnetic field generated by the current to pass more smoothly through the rotor core in the q-axis direction, thus significantly increasing the q-axis inductance. The combined effect of the inner and outer layers of V-shaped magnet slots (1, 2, 3, and 4) with 35°≤β-α≤50° creates a strong magnetic field barrier in the d-axis direction, resulting in very high magnetic reluctance in the d-axis magnetic circuit. This keeps the d-axis inductance at a very low level, thereby increasing the saliency of the motor and effectively improving the torque density of the motor. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the rotor in the electric motor provided by this utility model; Figure 2 for Figure 1 A magnified view of a portion of the image; Figure 3 A schematic diagram of the structure of an embodiment of the stator in the motor provided by this utility model.

[0022] Explanation of icon numbers: 10. Stator; 11. Stator slot; 12. Protrusion; 13. Welding slot; 20. Rotor; 21. Magnet slot; 211. First magnet slot; 212. Second magnet slot; 213. Third magnet slot; 214. Fourth magnet slot; 21a. Main body section; 21b. Magnet adjustment section; 22. Magnet adjustment slot; 23. First weight reduction hole; 24. Second weight reduction hole; 25. Fastening point; 30. Permanent magnet.

[0023] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] 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. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0025] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0026] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0027] Reference Figure 1 and Figure 2 This utility model proposes an electric motor, comprising: Stator 10; and The rotor 20 is rotatably mounted within the stator 10. The rotor 20 includes multiple rotor laminations stacked on top of each other. Each rotor lamination has multiple sets of magnet slots 21. Each set of magnet slots 21 includes a first magnet slot 211, a second magnet slot 212, a third magnet slot 213, and a fourth magnet slot 214. The first magnet slot 211 and the second magnet slot 212 are symmetrically arranged in the radial direction of the rotor 20. The third magnet slot 213 and the fourth magnet slot 214 are also symmetrically arranged in the radial direction of the rotor 20. The third magnet slot 213 and the fourth magnet slot 214 are both located outside the first magnet slot 211 and the second magnet slot 212. The included angle between the first magnet slot 211 and the second magnet slot 212 is α, and the included angle between the third magnet slot 213 and the fourth magnet slot 214 is β, where 35°≤β-α≤50°.

[0028] In the technical solution of this utility model, each set of magnetic slots 21 is arranged as a first magnetic slot 211, a second magnetic slot 212, a third magnetic slot 213, and a fourth magnetic slot 214, that is, each set of magnetic slots 21 is arranged in a double V shape; furthermore, the included angle between the first magnetic slot 211 and the second magnetic slot 212 is α, and the included angle between the third magnetic slot 213 and the fourth magnetic slot 214 is β, 35°≤β-α≤50°, wherein the magnetic path of the q-axis is widened by the third magnetic slot 213 and the fourth magnetic slot 214. This allows the magnetic field generated by the current to pass more smoothly through the rotor 20 core in the q-axis direction, thus significantly increasing the q-axis inductance. The inner and outer layers of V-shaped magnetic slots 21 of the first magnetic slot 211, the second magnetic slot 212, the third magnetic slot 213, and the fourth magnetic slot 214 work together, with 35°≤β-α≤50°, thus forming a strong magnetic field barrier in the d-axis direction. This results in very high magnetic reluctance of the d-axis magnetic circuit, thereby keeping the d-axis inductance at a very low level, which in turn increases the saliency ratio of the motor and effectively improves the torque density of the motor.

[0029] If β-α > 50°, meaning β is too large relative to α, the excessively widened third and fourth magnet slots 213 and 214 will cut or weaken the core path that should be prepared for the q-axis flux, resulting in a decrease in q-axis inductance or an inability to effectively suppress the d-axis inductance to a low level. This reduces the inductance difference between the d-axis and q-axis, thereby reducing the saliency ratio and torque density of the motor. Conversely, if β-α < 35°, the q-axis magnetic circuit cannot be effectively widened and optimized due to the increased "opening" of the third and fourth magnet slots 213 and 214, and the d-axis magnetic circuit cannot form a more effective constraint due to the difference in the magnetic barrier angles of the inner and outer magnet slots 21. This prevents the difference between the d-axis and q-axis inductance from being maximized, thus reducing the saliency ratio and torque density of the motor.

[0030] In this context, α and β are both measured in degrees. Since the magnet groove 21 is irregularly shaped and the permanent magnet 30 is square, the measurement method for α is as follows: draw the extension line of the permanent magnet 30 in the length direction within the first magnet groove 211 as the first extension line, draw the extension line of the permanent magnet 30 in the length direction within the second magnet groove 212 as the second extension line, and then measure the angle between the first extension line and the second extension line, which is α. The measurement method for β is similar to the above and will not be described in detail.

[0031] Furthermore, by setting the included angles between the corresponding magnet slots 21 reasonably, the saliency ratio of the motor is further optimized, and the torque density of the motor is improved, with 90°≤α≤105° and 135°≤β≤145°. At the same time, the magnetic field distribution of the rotor 20 is optimized, avoiding situations where the magnetic flux density is too high or changes drastically in certain local areas. This effectively reduces the iron loss of the rotor 20, especially the eddy current loss in the permanent magnet 30, thereby improving the motor efficiency.

[0032] Specifically, 97.4°≤α≤97.9°, 140.15°≤β≤140.65°. By further optimizing the included angle α between the first magnet slot 211 and the second magnet slot 212, and the included angle β between the third magnet slot 213 and the fourth magnet slot 214, the saliency ratio of the motor is further optimized, thereby further improving the torque density of the motor.

[0033] In one embodiment, the outer peripheral wall of the rotor 20 laminations is provided with magnetic adjustment slots 22, and each group of magnet slots 21 is provided with two magnetic adjustment slots 22, which are symmetrically arranged in the radial direction of the rotor 20. By providing magnetic adjustment slots 22, specific cogging torque harmonics are effectively canceled, thereby changing the magnetic circuit characteristics of the motor, making the air gap magnetic field distribution more sinusoidal, thus significantly reducing cogging torque and torque pulsation caused by current commutation, and thus reducing the vibration and noise of the motor.

[0034] Furthermore, the magnetic adjustment slot 22 is elliptical in shape. This further optimizes the slope of magnetic flux change, suppresses specific harmonics, makes magnetic field switching smoother, reduces torque pulsation, and the smooth slot shape avoids sudden changes in magnetic field, reducing the amplitude of the radial electromagnetic force acting on the stator 10, thereby reducing vibration and noise. At the same time, the elliptical shape has no sharp corners, which makes the stress distribution of the rotor 20 laminations uniform, reduces the risk of fatigue damage, improves mechanical reliability, and thus increases the service life of the rotor 20.

[0035] Specifically, the length of the long half-axis of the magnetic adjustment slot 22 is 'a', and the length of the short half-axis of the magnetic adjustment slot 22 is 'b', where 2.9 ≤ a / b ≤ 3.1. By further optimizing the size of the magnetic adjustment slot 22, the magnetic field of the rotor 20 is further optimized, making the air gap magnetic field distribution closer to a sinusoid, thereby further reducing cogging torque and torque pulsation, and further reducing the vibration and noise of the motor.

[0036] Motor vibration and noise are not uniformly generated by forces of all frequencies, but are often dominated by a few specific orders of radial electromagnetic force waves. Therefore, in one embodiment, the centers of the two ellipses of the same set of magnetic adjustment slots 22 are respectively the center of the first ellipse and the center of the second ellipse. The circle passing through the center of the first ellipse and the center of the second ellipse is an auxiliary circle with a radius of r, 70mm ≤ r ≤ 80mm. The angle between the line connecting the center of the first ellipse and the center of the auxiliary circle, and the line connecting the center of the second ellipse and the center of the auxiliary circle, is γ, 7.9° ≤ γ ≤ 8.1°. By further optimizing the magnetic field distribution of the rotor 20, the specific harmonic orders that generate noise are weakened, thereby precisely and effectively reducing the noise sources of the rotor 20, thus reducing the vibration noise of the rotor 20, and improving the NVH performance of the motor.

[0037] In one embodiment, the plurality of rotor laminations 20 include at least two sets of rotor laminations 20, each set of rotor laminations 20 includes three stacks of rotor laminations 20, and each stack of rotor laminations 20 includes a plurality of rotor laminations 20 stacked together. The angle difference between the positions of the corresponding magnetic slots 21 on two adjacent stacks of rotor laminations in the same set of rotor laminations 20 is θ, where 2.4°≤θ≤2.6°. The deflection directions of the corresponding magnetic slots 21 on two adjacent sets of rotor laminations 20 are opposite, and the positions of the corresponding magnetic slots 21 on two adjacent stacks of rotor laminations in two adjacent sets of rotor laminations 20 are the same.

[0038] Understandably, torque pulsation and cogging torque are mainly caused by spatial harmonics generated by the interaction between the stator 10 cogging and the rotor 20 magnetic poles. Therefore, by misaligning the six stacks of rotor 20 laminations in both directions, a large torque pulsation is effectively "averaged" into multiple continuous small pulsations, thereby reducing the peak value. This allows the harmonics to cancel each other out and weaken each other when they are transmitted to the stator 10 and the housing, thus effectively smoothing the total torque output, reducing the motor's torque pulsation, and making the motor run extremely smoothly.

[0039] In one embodiment, the rotor 20 laminations are provided with first weight-reduction holes 23, and each group of magnet slots 21 corresponds to one first weight-reduction hole 23. The first weight-reduction hole 23 is located between the first magnet slot 211 and the second magnet slot 212 in the same group of magnet slots 21. By providing the first weight-reduction holes 23, the weight of the rotor 20 core can be reduced, which is beneficial to the miniaturization of the rotor 20. On the other hand, it can also play a role in regulating the magnetic field, thereby making the magnetic field distribution more uniform, which is beneficial to reducing the torque pulsation and noise of the motor, and thus improving the performance of the motor.

[0040] In one embodiment, the rotor 20 laminations are provided with second weight-reduction holes 24, which are located between the first magnet slot 211 of a set of magnet slots 21 and the second magnet slot 212 of an adjacent set of magnet slots 21. By providing the second weight-reduction holes 24, the weight of the rotor 20 core can be reduced, thus facilitating the miniaturization of the rotor 20; on the other hand, it can also regulate the magnetic field, making the magnetic field distribution more uniform, thereby reducing motor torque ripple and noise, and thus improving motor performance.

[0041] Reference Figure 1 and Figure 3 In one embodiment, the stator 10 has 54 stator slots 11, and the rotor 20 has 6 poles. Understandably, when the motor uses 6 poles and 54 slots, it means that the cogging torque fluctuates 54 times per revolution of the rotor 20. The more fluctuations, the smaller the mechanical angle of each fluctuation. The distance the magnetic pole travels from one cogging alignment position to the next is short, resulting in a smoother change in magnetic reluctance. Therefore, the amplitude (peak value) of the cogging torque is significantly reduced, thereby reducing the motor's cogging torque and torque pulsation, and consequently reducing the motor's vibration and noise.

[0042] To smooth the air gap magnetic flux density distribution and make the magnetic field closer to an ideal sine wave, existing technologies often employ irregularly shaped permanent magnets 30. However, irregularly shaped permanent magnets 30 are often machined as a single piece, resulting in high processing difficulty. Therefore, in one embodiment, the motor further includes a permanent magnet 30, and the magnetic steel groove 21 includes a connected main body section 21a and two magnetic adjustment sections 21b. The two magnetic adjustment sections 21b are located at both ends of the main body section 21a. The main body section 21a is adapted to accommodate the permanent magnet 30 with a rectangular cross-section, and the magnetic adjustment sections 21b are irregularly shaped. Understandably, in the technical solution of this application, by designing the permanent magnet 30 as square and smoothing the air gap magnetic flux density distribution through the magnetic adjustment section 21b of the magnetic steel groove 21, the magnetic field is made closer to the ideal sine wave, thereby simplifying the processing method of the permanent magnet 30. Secondly, the rotor 20 is composed of multiple stacked rotor 20 laminations. Therefore, when designing the irregular magnetic adjustment section 21b, its processing is relatively convenient, thereby simplifying the processing technology of the rotor 20.

[0043] In one embodiment, the outer peripheral wall of the stator 10 is provided with a protrusion 12, which facilitates the connection of the stator 10 with external components or housing, thereby improving the installation efficiency of the stator 10.

[0044] The stator 10 has a welding groove 13 on its outer peripheral wall. Understandably, the stator 10 includes a plurality of stacked stator 10 laminations. Adjacent stator 10 laminations are welded together through the welding groove 13. The welding method is mature and stable, and the connection strength is high, thereby improving the stability and reliability of the stator 10 and thus improving the service life of the stator 10.

[0045] The rotor 20 laminations are provided with snap points 25. After multiple rotor 20 laminations are stacked, they are riveted together by the cooperation of the snap points 25. The connection strength through the snap points 25 is high and can withstand the huge centrifugal force generated by high-speed rotation. Moreover, the cold working process does not damage the insulation layer between the laminations and the eddy current loss is small, thereby improving the yield and service life of the rotor 20 laminations.

[0046] This utility model also proposes a vehicle that includes a motor. The specific structure of the motor is as described in the above embodiments. Since this vehicle adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0047] The above description is merely an exemplary embodiment of the present utility model and does not limit the scope of protection of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present utility model.

Claims

1. An electric motor, characterized in that, include: stator; and The rotor is rotatably mounted within the stator. The rotor includes multiple rotor laminations stacked on top of each other. Each rotor lamination has multiple sets of magnet slots. Each set of magnet slots includes a first magnet slot, a second magnet slot, a third magnet slot, and a fourth magnet slot. The first and second magnet slots are symmetrically arranged in the radial direction of the rotor. The third and fourth magnet slots are also symmetrically arranged in the radial direction of the rotor. The third and fourth magnet slots are located outside the first and second magnet slots. The included angle between the first and second magnet slots is α, and the included angle between the third and fourth magnet slots is β, where 35°≤β-α≤50°.

2. The motor as described in claim 1, characterized in that, 90°≤α≤105°，135°≤β≤145°。 3. The motor as described in claim 2, characterized in that, 97.4°≤α≤97.9°，140.15°≤β≤140.65°。 4. The motor as described in claim 1, characterized in that, The outer peripheral wall of the rotor lamination is provided with a magnetic adjustment groove, and each group of magnetic slots is provided with two magnetic adjustment grooves, which are symmetrically arranged in the radial direction of the rotor.

5. The motor as described in claim 4, characterized in that, The magnetic adjustment slot is elliptical in shape.

6. The motor as described in claim 5, characterized in that, The length of the long half-axis of the magnetic adjustment slot is a, and the length of the short half-axis of the magnetic adjustment slot is b, where 2.9 ≤ a / b ≤ 3.

1.

7. The motor as described in claim 5, characterized in that, The centers of the two elliptical grooves in the same group are the first elliptical center and the second elliptical center, respectively. The circle passing through the first elliptical center and the second elliptical center is an auxiliary circle with a radius of r, 70mm≤r≤80mm. The angle between the line connecting the first elliptical center and the center of the auxiliary circle and the line connecting the second elliptical center and the center of the auxiliary circle is γ, 7.9°≤γ≤8.1°.

8. The motor as described in claim 1, characterized in that, The plurality of rotor laminations includes at least two sets of rotor laminations, each set of rotor laminations includes three stacks of rotor laminations, and each stack of rotor laminations includes a plurality of rotor laminations stacked together. The angle difference between the positions of the corresponding magnetic slots on two adjacent stacks of rotor laminations in the same set of rotor laminations is θ, where 2.4°≤θ≤2.6°. The deflection directions of the corresponding magnetic slots on two adjacent sets of rotor laminations are opposite, and the positions of the corresponding magnetic slots on two adjacent stacks of rotor laminations in two adjacent sets of rotor laminations are the same.

9. The motor as described in claim 1, characterized in that, The rotor lamination is provided with a first weight reduction hole, and each group of magnet slots corresponds to one first weight reduction hole. The first weight reduction hole is located between the first magnet slot and the second magnet slot in the same group of magnet slots.

10. The motor as described in claim 1, characterized in that, The rotor lamination is provided with a second weight reduction hole, which is located between the first magnet slot of a set of magnet slots and the second magnet slot of an adjacent set of magnet slots.

11. The motor as described in claim 1, characterized in that, The stator has 54 stator slots, and the rotor has 6 poles.

12. The motor as described in claim 1, characterized in that, The motor also includes a permanent magnet. The magnetic steel groove includes a main body section and two magnetic adjustment sections connected to each other. The two magnetic adjustment sections are respectively located at both ends of the main body section. The main body section is adapted to accommodate the permanent magnet with a rectangular cross-section. The magnetic adjustment sections are irregularly shaped.

13. The motor as described in claim 1, characterized in that, The stator has protrusions on its outer peripheral wall; and / or The stator has a welding groove on its outer peripheral wall; and / or The rotor laminations are provided with snap points.

14. A vehicle, characterized in that, Includes the motor as described in any one of claims 1 to 13.

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