Rotor, electric machine, braking system and vehicle

Abstract

The application provides a rotor, a motor, a braking system and a vehicle. The rotor comprises: a rotor core, a plurality of first grooves are arranged on the outer circumferential wall of the rotor core, and a plurality of lightening holes are arranged on the part of the rotor core between the shaft hole and the outer circumferential wall of the rotor core; a plurality of permanent magnets are arranged on the outer circumferential wall of the rotor core, and one first groove is arranged between any two adjacent permanent magnets; on the axial end surface of the rotor core, the maximum distance from the center of the shaft hole to the side of the permanent magnet away from the rotor core is R1, the minimum distance from the center of the shaft hole to the hole wall of the lightening hole is R2, the radius of the shaft hole is R3, the maximum width of the permanent magnet in the direction from the lightening hole to the shaft hole is Lm, and the minimum distance from the point on the hole wall of the lightening hole to the outer circumferential wall of the rotor core is L1; wherein, R1-R2-Lm-L1

Description

Technical Field

[0001] This application relates to the field of electric motor technology, and more specifically, to a rotor, an electric motor, a braking system, and a vehicle. Background Technology

[0002] As a power source for electrical appliances or various mechanical equipment, an electric motor can generate driving torque when it is working.

[0003] With the rapid development of society, electric motors have received increasing attention, and the performance requirements for them are also becoming more stringent. In related technologies, the large moment of inertia of electric motors increases the difficulty of starting them, thus affecting their overall performance. Utility Model Content

[0004] This application aims to address at least one of the technical problems existing in the prior art or related technologies.

[0005] Therefore, the first aspect of this application proposes a rotor.

[0006] The second aspect of this application proposes an electric motor.

[0007] The third aspect of this application proposes a braking system.

[0008] The fourth aspect of this application proposes a vehicle.

[0009] In view of the above, the first aspect of this application provides a rotor, comprising: a rotor core having a shaft hole, a plurality of first grooves on the outer peripheral wall of the rotor core, and a plurality of weight-reducing holes in the portion of the rotor core located between the shaft hole and the outer peripheral wall of the rotor core, the plurality of weight-reducing holes and the plurality of first grooves being arranged circumferentially spaced along the shaft hole, and the shaft hole, the weight-reducing holes and the first grooves all penetrating two axial end faces of the rotor core; and a plurality of permanent magnets disposed on the outer peripheral wall of the rotor core, the plurality of permanent magnets being arranged circumferentially spaced along the shaft hole. The rotor core has a first groove between any two adjacent permanent magnets. On the axial end face of the rotor core, the maximum distance from the center of the shaft hole to the side of the permanent magnet away from the rotor core is R1, the minimum distance from the center of the shaft hole to the wall of the weight reduction hole is R2, the radius of the shaft hole is R3, the maximum width of the permanent magnet in the direction from the weight reduction hole to the shaft hole is Lm, and the minimum distance from a point on the wall of the weight reduction hole to the outer peripheral wall of the rotor core is L1. Wherein, R1-R2-Lm-L1<R1-R3.

[0010] This application provides a rotor comprising a rotor core and a plurality of permanent magnets. The plurality of permanent magnets are disposed on the outer peripheral wall of the rotor core and are arranged at intervals along the circumferential direction of the shaft hole. That is, the plurality of permanent magnets are disposed on the outer peripheral wall of the rotor core in a surface-mount manner.

[0011] The rotor core has a shaft hole, and its outer peripheral wall has multiple first grooves. The portion of the rotor core between the shaft hole and the outer peripheral wall has multiple weight-reducing holes. The multiple first grooves and weight-reducing holes are arranged at intervals along the circumference of the shaft hole. The shaft hole penetrates both axial end faces of the rotor core, as do the first grooves and weight-reducing holes.

[0012] The rotor shaft passes through the shaft hole. The weight-reducing hole serves to reduce weight. The first groove is used to mate with the rotor's positioning component to limit the mating positions of multiple permanent magnets and the rotor core.

[0013] On the axial end face of the rotor core, the maximum distance from the center of the shaft hole to the side of the permanent magnet away from the rotor core is denoted as R1, the minimum distance from the center of the shaft hole to the wall of the weight-reducing hole is denoted as R2, the radius of the shaft hole is denoted as R3, the maximum width of the permanent magnet in the direction from the weight-reducing hole to the shaft hole is denoted as Lm, and the minimum distance from a point on the wall of the weight-reducing hole to the outer peripheral wall of the rotor core is denoted as L1. That is, the inner diameter of the rotor core is 2 × R3.

[0014] The moment of inertia of an electric motor is related to the rotor's mass distribution and the shaft's mounting position. This application defines the relationship between R1, R2, R3, L1, and Lm to satisfy: R1 - R2 - Lm - L1 < R1 - R3. This configuration not only meets the requirements for effectively assembling the rotor core and multiple permanent magnets but also establishes a matching relationship between the shaft hole, weight-reduction hole, first groove, and the permanent magnet's mounting position. This optimizes the rotor's mass distribution and the shaft's mounting position, thereby reducing the motor's moment of inertia, simplifying starting, and ensuring optimal motor performance.

[0015] Simultaneously, the combined structure of the defined shaft hole, weight-reducing hole, first groove, and permanent magnet can also adjust the direction of magnetic field lines, thereby regulating the magnetic field distribution. This avoids oversaturation and undersaturation regions in the magnetic flux density design, thereby increasing the motor's output torque and reducing torque ripple, effectively lowering the motor's operating noise.

[0016] It is understandable that excessive rotor weight increases centrifugal load, reduces rotor core fatigue life, and increases motor moment of inertia. Setting multiple weight-reducing holes helps reduce motor moment of inertia. Associating L1 with R1, R2, R3, and Lm links the position of the weight-reducing holes to the position of the shaft hole, the outer peripheral wall of the rotor core, and the permanent magnet. The position of the weight-reducing holes differs for shafts of different outer diameters, rotor cores of different sizes, and permanent magnets of different sizes. If the weight-reducing holes are placed too close to the shaft hole, it increases the stress level inside the shaft hole. If the weight-reducing holes are placed too close to the outer peripheral wall of the rotor core, it affects the stress and magnetic circuit on the outer circumference of the rotor core, thus affecting motor torque. Therefore, this application rationally designs the rotor structure, balancing the reduction of motor moment of inertia with ensuring motor performance.

[0017] The rotor described above according to this application may also have the following additional technical features:

[0018] In some embodiments, R1, R2, R3, L1, and Lm may optionally satisfy: 0.15 ≤ (R1-R2-Lm-L1) / (R1-R3) ≤ 0.6.

[0019] In this embodiment, the matching relationship of parameters R1, R2, R3, L1 and Lm is further defined.

[0020] Specifically, R1, R2, R3, L1, and Lm satisfy the following condition: 0.15 ≤ (R1 - R2 - Lm - L1) / (R1 - R3) ≤ 0.6. That is, when the ratio of (R1 - R2 - Lm - L1) to (R1 - R3) is within the range of 0.15 to 0.6, it balances reducing the motor's moment of inertia with ensuring its performance, reducing the difficulty of starting the motor, decreasing torque ripple, and effectively suppressing vibration and noise.

[0021] In some embodiments, the portion of the rotor core located between two adjacent weight-reduction holes is disposed opposite to a first groove.

[0022] In this embodiment, a mating structure is further defined for multiple weight-reducing holes, multiple first grooves, shaft holes, and multiple permanent magnets. The multiple weight-reducing holes, multiple first grooves, and multiple permanent magnets are all arranged circumferentially at intervals along the shaft holes. A first groove is provided between any two adjacent permanent magnets, and the portion of the rotor core located between two adjacent weight-reducing holes is positioned opposite one of the first grooves.

[0023] This setting optimizes the rotor's mass distribution, which helps to achieve a balanced rotor mass distribution, thereby reducing the unbalanced forces during rotor rotation when the motor is working, and thus reducing the motor's moment of inertia.

[0024] In some embodiments, the rotor core may optionally include a plurality of stacked rotor laminations, the first axial end face of the rotor laminations being provided with a plurality of second grooves, and the second axial end face of the rotor laminations being provided with a plurality of protrusions; in two adjacent rotor laminations, each protrusion of one rotor lamination is interference-fitted with a second groove of another rotor lamination; wherein, the number of protrusions of the rotor laminations is 2×p, where p is the number of pole pairs.

[0025] In this embodiment, the structure of the rotor core is further defined.

[0026] The rotor core consists of multiple rotor laminations stacked together.

[0027] Along the axial direction of the rotor, any one of the multiple rotor laminations includes a first axial end face and a second axial end face. The first axial end face is provided with multiple second grooves, and the second axial end face is provided with multiple protrusions.

[0028] In two adjacent rotor laminations, multiple protrusions of one rotor lamination are correspondingly arranged with multiple second grooves of the other rotor lamination. Each protrusion of one rotor lamination is interference-fitted with one second groove of the other rotor lamination. For example, N protrusions and N second grooves of two adjacent rotor laminations are fitted together to form N press-fit structures. Two adjacent rotor laminations are assembled together by N press-fit structures. N press-fit structures can connect and fix two adjacent rotor laminations from multiple directions and multiple positions to enhance the rigidity of the assembly structure of multiple rotor laminations.

[0029] Specifically, the number of protrusions in the rotor laminations is 2×p, where p is the number of pole pairs. Alternatively, the number of second grooves in the rotor laminations is 2×p. This arrangement ensures the connection area between adjacent rotor laminations, guarantees the structural strength of the assembly of multiple rotor laminations, prevents lamination from falling apart, and provides structural support to ensure the dimensional stability of the rotor core.

[0030] In some embodiments, optionally, on the first axial end face of the rotor lamination, each second groove is disposed opposite to a first groove, the minimum distance from a point on the wall of the weight reduction hole to the center line of the first groove is L2, the maximum distance between any two points on the wall of the second groove is D1, the thickness of the rotor lamination is d, and the center line of the first groove passes through the center of the opening of the first groove and the center of the bottom of the first groove; wherein, L2-D1 / 2-d<R2×sin(π / 2 / p).

[0031] In this embodiment, the structure of the rotor core is further defined.

[0032] On the first axial end face of the rotor lamination, each second groove is arranged opposite to a first groove.

[0033] On the first axial end face of the rotor lamination, the minimum distance from a point on the wall of the weight reduction hole to the center line of the first groove is denoted as L2, the maximum distance between any two points on the wall of the second groove is denoted as D1, and the thickness of the rotor lamination is denoted as d. The center line of the first groove passes through the center of the groove opening and the center of the groove bottom of the first groove.

[0034] By defining the relationship between L2, D1, d, R2, and p, we ensure that L2 - D1 / 2 - d < R2 × sin(π / 2 / p). This defines the positional relationship between the weight-reducing hole, the second groove, and the shaft hole. This approach ensures the structural strength of the rotor laminations, preventing localized warping that could affect the rotor core's dimensions. Furthermore, it considers the motor's magnetic circuit, reducing distortion and thus minimizing torque ripple. This provides reliable structural support for ensuring the motor's performance.

[0035] In some embodiments, L2, D1, d, R2, and p may optionally satisfy: 0 ≤ (L2 - D1 / 2 - d) / (R2 × sin(π / 2 / p)) ≤ 0.5.

[0036] In this embodiment, the matching relationship of parameters L2, D1, d, R2 and p is further defined.

[0037] Specifically, L2, D1, d, R2, and p satisfy: 0 ≤ (L2 - D1 / 2 - d) / (R2 × sin(π / 2 / p)) ≤ 0.5.

[0038] That is, when the ratio of (L2-D1 / 2-d) and (R2×sin(π / 2 / p)) is in the range of 0 to 0.5, the structural strength of the rotor lamination and the performance of the motor are taken into account, which is beneficial to reducing distortion and reducing the torque pulsation of the motor.

[0039] In some embodiments, R2, R3, d, and L1 may optionally satisfy: R2-R3≥d, L1≥d.

[0040] In this embodiment, on the axial end face of the rotor core, the minimum distance from the center of the shaft hole to the wall of the weight reduction hole is R2, the radius of the shaft hole is R3, the thickness of the rotor lamination is d, and the minimum distance from a point on the wall of the weight reduction hole to the outer peripheral wall of the rotor core is L1.

[0041] The relationships between R2, R3, d, and L1 are defined to satisfy: R2 - R3 ≥ d, L1 ≥ d. The distances between the weight-reduction hole and the shaft hole walls, and between the rotor core's outer peripheral wall, are also defined. This ensures that the rotor core's structural strength is maintained while reducing its weight, preventing deformation.

[0042] Understandably, if R2-R3 < d, and / or L1 < d, then the distance from the weight-reducing hole to the wall of the shaft hole is relatively short, and / or the distance from the weight-reducing hole to the outer peripheral wall of the rotor core is relatively short. Therefore, the structural strength of the rotor core at the weight-reducing hole is low, making it prone to localized deformation. This compromises the dimensional integrity of the rotor core, consequently compromising the fit between the rotor and the motor stator, and ultimately reducing the motor's performance.

[0043] In other words, the location of the weight-reduction holes varies depending on the outer diameter of the shaft and the rotor core. If the weight-reduction holes are too close to the shaft, it will increase the stress level on the inner side of the shaft hole. If the weight-reduction holes are too close to the outer circumferential wall of the rotor core, it will affect the stress on the outer circumferential side of the rotor core and the motor magnetic circuit, thus affecting the motor's torque and strength performance. By limiting the relationship between R2, R3, d, and L1, both the rotor weight reduction requirements and the motor performance requirements can be met, allowing the rotor core to deform and bear stress uniformly under centrifugal load. At the same time, the impact of the weight-reduction hole placement on electromagnetic performance is reduced.

[0044] In some embodiments, optionally, on the axial end face of the rotor core, the wall of the weight reduction hole includes a plurality of hole segments connected end to end, with any two adjacent hole segments having different extension directions, and the center of the weight reduction hole located on the magnetic pole center line; the plurality of hole segments include a first hole segment and a second hole segment connected to each other, the distance from the connection point of the first hole segment and the second hole segment to the outer peripheral wall of the rotor core is L1, and the included angle between the first hole segment and the second hole segment is α, wherein 50° < α < 100°.

[0045] In this embodiment, the shape of the weight-reducing hole is further defined, as well as the mating structure between the weight-reducing hole and the permanent magnet is defined.

[0046] On the axial end face of the rotor core, the wall of the weight reduction hole consists of multiple hole segments, which are connected end to end, and the extension directions of any two adjacent hole segments are different.

[0047] The multiple hole segments include a first hole segment and a second hole segment, which are connected. The distance from the connection point of the first hole segment and the second hole segment to the outer peripheral wall of the rotor core is L1. That is, the distance from the connection point of the first hole segment and the second hole segment to the outer peripheral wall of the rotor core is the minimum distance from a point on the wall of the weight reduction hole to the outer peripheral wall of the rotor core.

[0048] The first and second hole segments enclose an angular structure, with an included angle of α, where 50° < α < 100°. This design balances the size of the weight-reducing holes with the distance from the holes to the outer peripheral wall of the rotor core. This reduces the weight of the rotor core while maintaining its structural strength and preventing deformation.

[0049] The line connecting the center of the permanent magnet and the center of the shaft hole forms the magnetic pole centerline, referred to as the d-axis. The center of the weight-reducing hole is located on the magnetic pole centerline. This arrangement achieves a balanced and consistent mass distribution in the rotor core. While ensuring that motor performance is not affected, the weight-reducing hole can reduce the motor's moment of inertia and lighten the overall weight of the motor.

[0050] In some embodiments, optionally, on the axial end face of the rotor core, the circumferential length of the opening of the first groove is less than the circumferential length of the bottom of the first groove, the width of the bottom of the first groove is L3, the distance from the opening of the first groove to the bottom of the first groove is L4, and the length of the portion of the outer peripheral wall of the rotor core located between two adjacent first grooves is L5; wherein, L3×L4<L5×(R1-Lm-R3).

[0051] In this embodiment, the structure of the first groove is further defined.

[0052] On the axial end face of the rotor core, the circumferential length of the opening of the first groove is less than the circumferential length of the bottom of the first groove. For example, the first groove has a structure with a small opening and a large bottom. For example, the shape of the first groove is T-shaped. It can be understood that the shape of the positioning component used to limit the multiple permanent magnets and the rotor core is adapted to the shape of the first groove. When assembling the positioning component, the positioning component is inserted axially into the first groove through the shaft hole of the rotor core. The shape of the first groove has the function of radially limiting the positioning component along the rotor core to ensure that the positioning component effectively limits the multiple permanent magnets.

[0053] On the axial end face of the rotor core, the distance from the opening of the first groove to the bottom of the first groove is denoted as L4, and the length of the portion of the outer peripheral wall of the rotor core located between two adjacent first grooves is denoted as L5.

[0054] By defining the relationship between L4 and L5 to satisfy L3×L4<L5×(R1-Lm-R3), the size of the first groove on the axial end face of the rotor core is defined, ensuring the fit between the first groove and the positioning component. This ensures the stability and effectiveness of assembling the rotor core and multiple permanent magnets. At the same time, this setting will not affect the torque pulsation of the motor, and can meet the low operating noise requirements of the motor.

[0055] In some embodiments, L3, L4, L5, R1, Lm, and R3 may optionally satisfy: 0.025 ≤ L3 × L4 / (L5 × (R1 - Lm - R3)) ≤ 0.08.

[0056] In this embodiment, the matching relationship of parameters L3, L4, L5, R1, Lm and R3 is further defined.

[0057] Specifically, L3, L4, L5, R1, Lm, and R3 satisfy the following condition: 0.025 ≤ L3 × L4 / (L5 × (R1 - Lm - R3)) ≤ 0.08. That is, when the ratio of (L3 × L4) to (L5 × (R1 - Lm - R3)) is within the range of 0.025 and 0.08, the effectiveness and feasibility of assembling the rotor core and multiple permanent magnets are considered, while ensuring the performance of the motor.

[0058] If L3×L4 / (L5×(R1-Lm-R3))<0.025, then the size of the first groove is small, and the mating area between the first groove and the positioning component is small, which will reduce the effectiveness of the positioning component in assembling the rotor core and multiple permanent magnets, and cannot effectively guarantee the mating dimensions of multiple permanent magnets and the rotor core.

[0059] If L3×L4 / (L5×(R1-Lm-R3))>0.08, it will affect the direction of the magnetic field lines, change the magnetic field distribution, increase the torque pulsation of the motor, and increase the operating noise of the motor.

[0060] In some embodiments, optionally, the permanent magnet is cross-sectioned along the axial direction perpendicular to the shaft hole. In the cross-section, the outline of the permanent magnet includes an arc segment and two straight segments. The arc segment connects the two straight segments, which are arranged circumferentially along the shaft hole. The arc segment is spaced apart from the rotor core, and the maximum distance between the two straight segments is Wm; where Lm × Wm < R1. 2 -R3 2 .

[0061] In this embodiment, the structure of the permanent magnet is further defined.

[0062] The permanent magnet is cross-sectioned along the axial direction perpendicular to the shaft hole. In the cross-section, the outline of the permanent magnet includes an arc segment and two straight segments. The two straight segments are arranged circumferentially along the shaft hole, and the arc segment connects the two straight segments. The arc segment is arranged at intervals from the rotor core.

[0063] Understandably, the outline of the permanent magnet on the side facing away from the rotor core is an arc segment. This arc segment is sandwiched between two straight segments.

[0064] The maximum distance between the two straight segments is denoted as Wm. On the axial end face of the rotor core, the maximum distance from the center of the shaft hole to the side of the permanent magnet away from the rotor core is denoted as R1, the radius of the shaft hole is denoted as R3, and the maximum width of the permanent magnet in the direction from the weight reduction hole to the shaft hole is denoted as Lm.

[0065] By defining the relationship between Lm, Wm, R1, and R3, we can ensure that Lm × Wm < R1. 2 -R3 2 This balances the motor's rotational inertia and torque ripple.

[0066] In some embodiments, optionally, Lm, Wm, R1, and R3 satisfy: 0.05 ≤ Lm × Wm / (R1 2 -R3 2 )≤0.2.

[0067] In this embodiment, the matching relationship of parameters Lm, Wm, R1, and R3 is further defined.

[0068] Specifically, Lm, Wm, R1, and R3 satisfy: 0.05 ≤ Lm × Wm / (R1 2 -R3 2 )≤0.2. That is, when (Lm×Wm) and (R1) 2 -R3 2 When the ratio of ) is in the range of 0.05 to 0.2, both the rotational inertia of the motor and the performance of the motor are taken into account.

[0069] If Lm×Wm / (R1) 2 -R3 2 If the value is less than 0.05, the permanent magnet will be too small, which will affect the distribution of the magnetic field and will not be able to effectively guarantee the torque pulsation of the motor.

[0070] If Lm×Wm / (R1) 2 -R3 2 If the value is greater than 0.2, the volume of the permanent magnet will be larger. If too much material is used in the permanent magnet, the weight of the rotor will increase, which will increase the moment of inertia of the motor.

[0071] In some embodiments, the rotor may optionally include: a shaft body passing through a shaft hole, the shaft body having a cylindrical structure and a wall thickness of less than or equal to 4 mm.

[0072] In this embodiment, the structure of the rotor is further defined, and the rotor also includes a shaft that passes through a shaft hole.

[0073] The shaft has a cylindrical structure, meaning it is hollow. The space enclosed by the inner circumference of the shaft is used for assembly with other components of the motor. By limiting the range of the shaft wall thickness to less than or equal to 4mm, the weight of the rotor can be reduced while ensuring the structural strength of the shaft, which helps to reduce the rotational inertia of the motor.

[0074] In some embodiments, p = 5.

[0075] In this embodiment, the specific range of values ​​for the pole logarithm is defined. Specifically, p = 5.

[0076] A second aspect of this application provides an electric motor comprising: a stator; and a rotor as in the first aspect, the stator surrounding the rotor, and the rotor being rotatable relative to the stator.

[0077] The motor provided in this application includes a stator and a rotor as described in the first aspect. Because it includes a rotor as described in the first aspect, it has all the beneficial effects of the rotor described above, which will not be described in detail here.

[0078] A third aspect of this application proposes a braking system comprising: an electric motor as described in the second aspect.

[0079] The braking system provided in this application includes a motor as described in the second aspect, and therefore has all the beneficial effects of the aforementioned motor, which will not be described in detail here.

[0080] The fourth aspect of this application proposes a vehicle comprising: an electric motor as in the second aspect; or a braking system as in the third aspect.

[0081] The vehicle provided in this application, having included an electric motor as described in the second aspect or a braking system as described in the third aspect, thus possesses all the beneficial effects of the aforementioned electric motor or braking system, which will not be described in detail here.

[0082] It is worth noting that the vehicle can be a new energy vehicle. New energy vehicles include pure electric vehicles, range-extended electric vehicles, hybrid electric vehicles, fuel cell electric vehicles, and hydrogen engine vehicles.

[0083] The vehicle can also be a gasoline-powered car.

[0084] Additional aspects and advantages of this application will become apparent in the following description or may be learned by practice of this application. Attached Figure Description

[0085] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0086] Figure 1 A schematic diagram of the first part of the rotor structure according to an embodiment of this application is shown;

[0087] Figure 2 A partial structural schematic diagram of a rotor core according to an embodiment of this application is shown;

[0088] Figure 3 A schematic diagram of the second part of the rotor structure according to an embodiment of this application is shown;

[0089] Figure 4 The diagram shows a curve illustrating how the ratio of the motor's torque to its moment of inertia varies with X.

[0090] in, Figures 1 to 3 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0091] 10 Rotor, 100 Rotor core, 110 Shaft hole, 120 First groove, 122 Centerline of the first groove, 130 Weight reduction hole, 132 Hole segment, 132a First hole segment, 132b Second hole segment, 140 Rotor lamination, 142 First axial end face, 144 Second axial end face, 146 Second groove, 148 Protrusion, 200 Permanent magnet, 210 Arc segment, 220 Straight segment, 300 Shaft. Detailed Implementation

[0092] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0093] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0094] The following reference Figures 1 to 4 This application describes rotor 10, motor, braking system, and vehicle according to some embodiments.

[0095] like Figure 1 , Figure 2 and Figure 3 As shown, a rotor 10 according to some embodiments of this application includes a rotor core 100 and a plurality of permanent magnets 200.

[0096] The rotor core 100 is provided with a shaft hole 110.

[0097] The outer peripheral wall of the rotor core 100 is provided with a plurality of first grooves 120.

[0098] The rotor core 100 is provided with multiple weight reduction holes 130 in the portion between the shaft hole 110 and the outer peripheral wall of the rotor core 100.

[0099] Multiple weight-reducing holes 130 and multiple first grooves 120 are arranged circumferentially along the shaft hole 110, and the shaft hole 110, weight-reducing holes 130 and first grooves 120 all penetrate the two axial end faces of the rotor core 100.

[0100] Multiple permanent magnets 200 are disposed on the outer peripheral wall of the rotor core 100.

[0101] Multiple permanent magnets 200 are arranged circumferentially along the shaft hole 110, and a first groove 120 is provided between any two adjacent permanent magnets 200.

[0102] On the axial end face of the rotor core 100, the maximum distance from the center of the shaft hole 110 to the side of the permanent magnet 200 away from the rotor core 100 is R1, the minimum distance from the center of the shaft hole 110 to the wall of the weight reduction hole 130 is R2, the radius of the shaft hole 110 is R3, the maximum width of the permanent magnet 200 in the direction from the weight reduction hole 130 to the shaft hole 110 is Lm, and the minimum distance from a point on the wall of the weight reduction hole 130 to the outer peripheral wall of the rotor core 100 is L1.

[0103] Where R1-R2-Lm-L1<R1-R3.

[0104] The rotor 10 provided in this application includes a rotor core 100 and a plurality of permanent magnets 200. The plurality of permanent magnets 200 are disposed on the outer peripheral wall of the rotor core 100 and are arranged at intervals along the circumferential direction of the shaft hole 110. That is, the plurality of permanent magnets 200 are disposed on the outer peripheral wall of the rotor core 100 in a surface-mount manner.

[0105] The rotor core 100 has a shaft hole 110, and its outer peripheral wall has a plurality of first grooves 120. The portion of the rotor core 100 located between the shaft hole 110 and the outer peripheral wall has a plurality of weight-reducing holes 130. The plurality of first grooves 120 are arranged circumferentially spaced along the shaft hole 110, and the plurality of weight-reducing holes 130 are also arranged circumferentially spaced along the shaft hole 110. The shaft hole 110 penetrates both axial end faces of the rotor core 100, the first grooves 120 penetrate both axial end faces of the rotor core 100, and the weight-reducing holes 130 also penetrate both axial end faces of the rotor core 100.

[0106] The shaft 300 of the rotor 10 passes through the shaft hole 110. The weight-reducing hole 130 has the function of reducing weight. The first groove 120 is used to cooperate with the positioning member of the rotor 10 to limit the cooperation position of the multiple permanent magnets 200 and the rotor core 100 by the positioning member.

[0107] On the axial end face of the rotor core 100, the maximum distance from the center of the shaft hole 110 to the side of the permanent magnet 200 away from the rotor core 100 is denoted as R1; the minimum distance from the center of the shaft hole 110 to the wall of the weight reduction hole 130 is denoted as R2; the radius of the shaft hole 110 is denoted as R3; the maximum width of the permanent magnet 200 in the direction from the weight reduction hole 130 to the shaft hole 110 is denoted as Lm; and the minimum distance from a point on the wall of the weight reduction hole 130 to the outer peripheral wall of the rotor core 100 is denoted as L1. That is, the inner diameter of the rotor core 100 is 2 × R3.

[0108] The moment of inertia of the motor is related to the mass distribution of the rotor 10 and the position of the shaft 300. This application defines the relationship between R1, R2, R3, L1, and Lm to satisfy: R1-R2-Lm-L1 < R1-R3. This setting not only meets the requirements for effectively assembling the rotor core 100 and multiple permanent magnets 200, but also establishes a matching relationship between the shaft hole 110, the weight reduction hole 130, the first groove 120, and the position of the permanent magnets 200, thereby optimizing the mass distribution of the rotor 10 and the installation position of the shaft 300. This reduces the moment of inertia of the motor, lowers the starting difficulty of the motor, and ensures the performance of the motor.

[0109] Meanwhile, the combined structure of the defined shaft hole 110, weight reduction hole 130, first groove 120, and permanent magnet 200 can also adjust the direction of magnetic field lines, thereby regulating the magnetic field distribution. This avoids oversaturation and undersaturation regions in the magnetic flux density design, thus reducing torque pulsation and lowering motor operating noise.

[0110] Understandably, excessive weight of the rotor 10 increases the centrifugal load on the rotor 10, reduces the fatigue life of the rotor core 100, and increases the moment of inertia of the motor. Setting multiple weight-reducing holes 130 helps reduce the moment of inertia of the motor. Associating L1 with R1, R2, R3, and Lm links the position of the weight-reducing holes 130 with the position of the shaft hole 110, the position of the outer peripheral wall of the rotor core 100, and the position of the permanent magnet 200. The position of the weight-reducing holes 130 differs for shafts 300 with different outer diameters, rotor cores 100s of different sizes, and permanent magnets 200s of different sizes. If the weight-reducing holes 130 are placed too close to the shaft hole 110, it will increase the stress level on the inner side of the shaft hole 110. If the weight-reducing holes 130 are placed too close to the outer peripheral wall of the rotor core 100, it will affect the stress and magnetic circuit on the outer circumferential side of the rotor core 100, thus affecting the torque of the motor. Therefore, this application has a reasonable structure for the rotor 10, which balances reducing the rotational inertia of the motor and ensuring the performance of the motor.

[0111] In some embodiments, R1, R2, R3, L1, and Lm may optionally satisfy: 0.15 ≤ (R1-R2-Lm-L1) / (R1-R3) ≤ 0.6.

[0112] In this embodiment, the matching relationship of parameters R1, R2, R3, L1 and Lm is further defined.

[0113] Specifically, R1, R2, R3, L1, and Lm satisfy the following condition: 0.15 ≤ (R1 - R2 - Lm - L1) / (R1 - R3) ≤ 0.6. That is, when the ratio of (R1 - R2 - Lm - L1) to (R1 - R3) is within the range of 0.15 to 0.6, it balances reducing the motor's moment of inertia with ensuring its performance, reducing the difficulty of starting the motor, decreasing torque ripple, and effectively suppressing vibration and noise.

[0114] Alternatively, the following values ​​are possible: (R1-R2-Lm-L1) / (R1-R3) = 0.2, (R1-R2-Lm-L1) / (R1-R3) = 0.25, (R1-R2-Lm-L1) / (R1-R3) = 0.3, (R1-R2-Lm-L1) / (R1-R3) = 0.36, (R1-R2-Lm-L1) / (R1-R3) = 0.4, (R1-R2-Lm-L1) / (R1-R3) = 0.42, (R1-R2-Lm-L1) / (R1-R3) = 0.45, and (R1-R2-Lm-L1) / (R1-R3) = 0.5, etc., which will not be listed here.

[0115] In some embodiments, such as Figure 1 As shown, optionally, the portion of the rotor core 100 located between two adjacent weight reduction holes 130 is positioned opposite a first groove 120.

[0116] In this embodiment, a mating structure is further defined for multiple weight-reducing holes 130, multiple first grooves 120, shaft holes 110, and multiple permanent magnets 200. The multiple weight-reducing holes 130, multiple first grooves 120, and multiple permanent magnets 200 are all arranged at circumferential intervals along the shaft holes 110. A first groove 120 is provided between any two adjacent permanent magnets 200, and the portion of the rotor core 100 located between two adjacent weight-reducing holes 130 is positioned opposite to one of the first grooves 120.

[0117] This setting optimizes the mass distribution of rotor 10, which helps to achieve a balanced mass distribution of rotor 10, thereby reducing the unbalanced force during the rotation of rotor 10 when the motor is working, and thus reducing the moment of inertia of the motor.

[0118] In some embodiments, optionally, such as Figure 2 As shown, the rotor core 100 includes a plurality of stacked rotor laminations 140.

[0119] The first axial end face 142 of the rotor lamination 140 is provided with a plurality of second grooves 146.

[0120] The second axial end face 144 of the rotor lamination 140 is provided with a plurality of protrusions 148.

[0121] In two adjacent rotor laminations 140, each protrusion 148 of one rotor lamination 140 is interference-fitted with a second groove 146 of the other rotor lamination 140.

[0122] The rotor lamination 140 has 2×p protrusions 148, where p is the number of pole pairs.

[0123] In this embodiment, the structure of the rotor core 100 is further defined.

[0124] The rotor core 100 includes multiple rotor laminations 140, which are stacked together.

[0125] Along the axial direction of the rotor 10, any one of the plurality of rotor laminations 140 includes a first axial end face 142 and a second axial end face 144. The first axial end face 142 is provided with a plurality of second grooves 146, and the second axial end face 144 is provided with a plurality of protrusions 148.

[0126] In two adjacent rotor laminations 140, a plurality of protrusions 148 of one rotor lamination 140 are correspondingly arranged with a plurality of second grooves 146 of the other rotor lamination 140. Each protrusion 148 of one rotor lamination 140 is interference-fitted with a second groove 146 of the other rotor lamination 140. For example, N protrusions 148 and N second grooves 146 of two adjacent rotor laminations 140 are fitted together to form N press-fit structures. Two adjacent rotor laminations 140 are assembled together by N press-fit structures. N press-fit structures can connect and fix two adjacent rotor laminations 140 from multiple directions and multiple positions to enhance the rigidity of the assembly structure of multiple rotor laminations 140.

[0127] Specifically, the number of protrusions 148 on the rotor lamination 140 is 2×p, where p is the number of pole pairs. Alternatively, the number of second grooves 146 on the rotor lamination 140 is 2×p. This arrangement ensures the connection area between adjacent rotor laminations 140, guarantees the structural strength of the assembly of multiple rotor laminations 140, prevents lamination from falling apart, and provides structural support for ensuring the external dimensions of the rotor core 100.

[0128] In some embodiments, optionally, on the first axial end face 142 of the rotor lamination 140, each second groove 146 is disposed opposite to a first groove 120.

[0129] On the first axial end face 142 of the rotor lamination 140, the minimum distance from a point on the wall of the weight reduction hole 130 to the center line 122 of the first groove is L2, the maximum distance between any two points on the groove wall of the second groove 146 is D1, the thickness of the rotor lamination 140 is d, and the center line 122 of the first groove passes through the center of the groove opening of the first groove 120 and the center of the groove bottom of the first groove 120.

[0130] Where L2-D1 / 2-d<R2×sin(π / 2 / p).

[0131] In this embodiment, the structure of the rotor core 100 is further defined.

[0132] On the first axial end face 142 of the rotor lamination 140, each second groove 146 is disposed opposite to a first groove 120.

[0133] On the first axial end face 142 of the rotor lamination 140, the minimum distance from a point on the wall of the weight reduction hole 130 to the center line 122 of the first groove is denoted as L2, the maximum distance between any two points on the groove wall of the second groove 146 is denoted as D1, and the thickness of the rotor lamination 140 is denoted as d. The center line 122 of the first groove passes through the center of the groove opening of the first groove 120 and the center of the groove bottom of the first groove 120.

[0134] By defining the relationship between L2, D1, d, R2, and p, we ensure that L2 - D1 / 2 - d < R2 × sin(π / 2 / p). This defines the positional relationship between the weight-reducing hole 130, the second groove 146, and the shaft hole 110. This ensures the structural strength of the rotor lamination 140, preventing localized warping of the laminations from affecting the external dimensions of the rotor core 100. Furthermore, it considers the motor's magnetic circuit, reducing distortion and thus minimizing torque ripple. This provides reliable structural support for ensuring the motor's performance.

[0135] In this embodiment, the groove wall of the second groove 146 on the first axial end face 142 of the rotor lamination 140 is circular.

[0136] In other embodiments, the shape enclosed by the groove wall of the second groove 146 on the first axial end face 142 of the rotor lamination 140 includes ellipse, polygon, or irregular shape, etc., which will not be listed here. Among them, irregular shape refers to an irregularly shaped graphic.

[0137] In some embodiments, L2, D1, d, R2, and p may optionally satisfy: 0 ≤ (L2 - D1 / 2 - d) / (R2 × sin(π / 2 / p)) ≤ 0.5.

[0138] In this embodiment, the matching relationship of parameters L2, D1, d, R2 and p is further defined.

[0139] Specifically, L2, D1, d, R2, and p satisfy: 0 ≤ (L2 - D1 / 2 - d) / (R2 × sin(π / 2 / p)) ≤ 0.5.

[0140] That is, when the ratio of (L2-D1 / 2-d) and (R2×sin(π / 2 / p)) is in the range of 0 to 0.5, the structural strength of the rotor lamination 140 and the performance of the motor are taken into account, which is beneficial to reducing distortion and reducing the torque pulsation of the motor.

[0141] Alternatively, the following values ​​are possible: (L2-D1 / 2-d) / (R2×sin(π / 2 / p))=0.1, (L2-D1 / 2-d) / (R2×sin(π / 2 / p))=0.15, (L2-D1 / 2-d) / (R2×sin(π / 2 / p))=0.2, (L2-D1 / 2-d) / (R2×sin(π / 2 / p))=0.24, (L2-D1 / 2-d) / (R2×sin(π / 2 / p))=0.3, (L2-D1 / 2-d) / (R2×sin(π / 2 / p))=0.36, and (L2-D1 / 2-d) / (R2×sin(π / 2 / p))=0.4, etc., which will not be listed here.

[0142] In some embodiments, R2, R3, d, and L1 may optionally satisfy: R2-R3≥d, L1≥d.

[0143] In this embodiment, on the axial end face of the rotor core 100, the minimum distance from the center of the shaft hole 110 to the wall of the weight reduction hole 130 is R2, the radius of the shaft hole 110 is R3, the thickness of the rotor lamination 140 is d, and the minimum distance from a point on the wall of the weight reduction hole 130 to the outer peripheral wall of the rotor core 100 is L1.

[0144] The relationships between R2, R3, d, and L1 are defined to satisfy: R2 - R3 ≥ d, L1 ≥ d. The distances between the weight-reducing hole 130, the hole wall of the shaft hole 110, and the outer peripheral wall of the rotor core 100 are also defined. This reduces the weight of the rotor core 100 while maintaining its structural strength and preventing deformation.

[0145] Understandably, if R2-R3 < d, and / or L1 < d, then the distance from the weight-reducing hole 130 to the wall of the shaft hole 110 is relatively short, and / or the distance from the weight-reducing hole 130 to the outer peripheral wall of the rotor core 100 is relatively short. Therefore, the structural strength of the rotor core 100 at the weight-reducing hole 130 is relatively low, making it prone to local deformation. This makes it impossible to guarantee the external dimensions of the rotor core 100, and consequently, the fit dimensions between the rotor 100 and the motor stator cannot be guaranteed, thus reducing the performance of the motor.

[0146] In other words, the position of the weight-reducing hole 130 varies depending on the outer diameter of the shaft 300 and the rotor core 100. If the weight-reducing hole 130 is too close to the shaft 300, it will increase the stress level on the inner side of the shaft hole 110. If the weight-reducing hole 130 is too close to the outer peripheral wall of the rotor core 100, it will affect the stress on the outer circumferential side of the rotor core 100 and the magnetic circuit of the motor, thus affecting the motor's torque and strength performance. By limiting the relationship between R2, R3, d, and L1, both the weight reduction requirements of the rotor 100 and the performance requirements of the motor can be met, and the rotor core 100 can be uniformly deformed and stressed under centrifugal load. At the same time, the influence of the placement of the weight-reducing hole 130 on the electromagnetic performance is reduced.

[0147] In some embodiments, optionally, such as Figure 1 As shown, on the axial end face of the rotor core 100, the wall of the weight reduction hole 130 includes a plurality of hole segments 132 connected end to end.

[0148] The extension directions of any two adjacent hole segments 132 are different.

[0149] The center of the weight reduction hole 130 is located on the magnetic pole center line.

[0150] The plurality of hole segments 132 include a first hole segment 132a and a second hole segment 132b that are connected to each other.

[0151] The distance from the connection point of the first hole section 132a and the second hole section 132b to the outer peripheral wall of the rotor core 100 is L1.

[0152] The angle between the first hole segment 132a and the second hole segment 132b is α.

[0153] Where 50° < a < 100°.

[0154] In this embodiment, the shape of the weight reduction hole 130 is further defined, as well as the mating structure between the weight reduction hole 130 and the permanent magnet 200 is defined.

[0155] On the axial end face of the rotor core 100, the wall of the weight reduction hole 130 includes multiple hole segments 132, which are connected end to end, and the extension directions of any two adjacent hole segments 132 are different.

[0156] The plurality of hole segments 132 include a first hole segment 132a and a second hole segment 132b, which are connected. The distance from the connection point of the first hole segment 132a and the second hole segment 132b to the outer peripheral wall of the rotor core 100 is L1. That is, the distance from the connection point of the first hole segment 132a and the second hole segment 132b to the outer peripheral wall of the rotor core 100 is the minimum distance from a point on the wall of the weight reduction hole 130 to the outer peripheral wall of the rotor core 100.

[0157] The first hole segment 132a and the second hole segment 132b form an angular structure, with an included angle α between them, where 50° < α < 100°. This design balances the size of the weight-reducing hole 130 and the distance from the weight-reducing hole 130 to the outer peripheral wall of the rotor core 100. In this way, while reducing the weight of the rotor core 100, the structural strength of the rotor core 100 is maintained, preventing deformation of the rotor core 100.

[0158] The line connecting the center of the permanent magnet 200 and the center of the shaft hole 110 forms the magnetic pole center line, referred to as the d-axis. The center of the weight reduction hole 130 is located on the magnetic pole center line. This arrangement achieves a balanced and consistent mass distribution of the rotor core 100. Under the premise of ensuring that the motor performance is not affected, the weight reduction hole 130 can reduce the rotational inertia of the motor and reduce the overall weight of the motor.

[0159] In this embodiment, there are five holes 132. The weight-reducing holes 130 have an approximately pentagonal structure.

[0160] In other embodiments, the number of aperture segments 132 includes three, four, six, or seven, etc., which will not be listed here.

[0161] In some embodiments, optionally, on the axial end face of the rotor core 100, the circumferential length of the groove opening of the first groove 120 is less than the circumferential length of the groove bottom of the first groove 120.

[0162] like Figure 1 As shown, on the axial end face of the rotor core 100, the width of the bottom of the first groove 120 is L3, the distance from the opening of the first groove 120 to the bottom of the first groove 120 is L4, and the length of the portion of the outer peripheral wall of the rotor core 100 located between two adjacent first grooves 120 is L5.

[0163] Where L3×L4<L5×(R1-Lm-R3).

[0164] In this embodiment, the structure of the first groove 120 is further defined.

[0165] On the axial end face of the rotor core 100, the circumferential length of the opening of the first groove 120 is less than the circumferential length of the bottom of the first groove 120. For example, the first groove 120 has a structure with a small opening and a large bottom. For example, the shape of the first groove 120 is T-shaped. It can be understood that the shape of the positioning member used to limit the multiple permanent magnets 200 and the rotor core 100 is adapted to the shape of the first groove 120. When assembling the positioning member, the positioning member is inserted into the first groove 120 axially through the shaft hole 110 of the rotor core 100. The shape of the first groove 120 has the function of radially limiting the positioning member along the rotor core 100, so as to ensure that the positioning member effectively limits the multiple permanent magnets 200.

[0166] On the axial end face of the rotor core 100, the distance from the opening of the first groove 120 to the bottom of the first groove 120 is denoted as L4, and the length of the portion of the outer peripheral wall of the rotor core 100 located between two adjacent first grooves 120 is denoted as L5.

[0167] By defining the relationship between L4 and L5 to satisfy L3×L4<L5×(R1-Lm-R3), the size of the first groove 120 on the axial end face of the rotor core 100 is defined, ensuring the fit dimensions between the first groove 120 and the positioning component. This ensures the stability and effectiveness of assembling the rotor core 100 and multiple permanent magnets 200. At the same time, this setting will not affect the torque pulsation of the motor and can meet the low operating noise requirements of the motor.

[0168] In some embodiments, L3, L4, L5, R1, Lm, and R3 may optionally satisfy: 0.025 ≤ L3 × L4 / (L5 × (R1 - Lm - R3)) ≤ 0.08.

[0169] In this embodiment, the matching relationship of parameters L3, L4, L5, R1, Lm and R3 is further defined.

[0170] Specifically, L3, L4, L5, R1, Lm, and R3 satisfy the following condition: 0.025 ≤ L3×L4 / (L5×(R1-Lm-R3)) ≤ 0.08. That is, when the ratio of (L3×L4) to (L5×(R1-Lm-R3)) is within the range of 0.025 and 0.08, the effectiveness and feasibility of assembling the rotor core 100 and multiple permanent magnets 200 are considered, while ensuring the performance of the motor.

[0171] If L3×L4 / (L5×(R1-Lm-R3))<0.025, then the size of the first groove 120 is small, and the mating area between the first groove 120 and the positioning component is small, which will reduce the effectiveness of the positioning component in assembling the rotor core 100 and multiple permanent magnets 200, and cannot effectively guarantee the mating dimensions between the multiple permanent magnets 200 and the rotor core 100.

[0172] If L3×L4 / (L5×(R1-Lm-R3))>0.08, it will affect the direction of the magnetic field lines, change the magnetic field distribution, increase the torque pulsation of the motor, and increase the operating noise of the motor.

[0173] Alternatively, the following values ​​are possible: L3×L4 / (L5×(R1-Lm-R3))=0.03, L3×L4 / (L5×(R1-Lm-R3))=0.034, L3×L4 / (L5×(R1-Lm-R3))=0.04, L3×L4 / (L5×(R1-Lm-R3))=0.046, L3×L4 / (L5×(R1-Lm-R3))=0.05, L3×L4 / (L5×(R1-Lm-R3))=0.055, L3×L4 / (L5×(R1-Lm-R3))=0.06, and L3×L4 / (L5×(R1-Lm-R3))=0.07, etc., which will not be listed here.

[0174] In some embodiments, the permanent magnet 200 may optionally be cross-sectioned along an axial direction perpendicular to the shaft hole 110, wherein the outline of the permanent magnet 200 includes an arc segment 210 and two straight segments 220.

[0175] Arc segment 210 connects two straight segments 220.

[0176] Two straight segments 220 are arranged circumferentially along the shaft hole 110.

[0177] The arc segment 210 and the rotor core 100 are arranged at intervals.

[0178] The maximum distance between the two straight line segments 220 is Wm.

[0179] Where Lm×Wm<R1 2 -R3 2 .

[0180] In this embodiment, the structure of the permanent magnet 200 is further defined.

[0181] The permanent magnet 200 is cross-sectioned along the axial direction perpendicular to the shaft hole 110. In the cross-section, the outline of the permanent magnet 200 includes an arc segment 210 and two straight segments 220. The two straight segments 220 are arranged circumferentially along the shaft hole 110. The arc segment 210 is connected between the two straight segments 220, and the arc segment 210 is spaced apart from the rotor core 100.

[0182] Understandably, the outline of the permanent magnet 200 on the side opposite to the rotor core 100 is an arc segment 210. The arc segment 210 is sandwiched between two straight segments 220.

[0183] The maximum distance between the two straight segments 220 is denoted as Wm. On the axial end face of the rotor core 100, the maximum distance from the center of the shaft hole 110 to the side of the permanent magnet 200 away from the rotor core 100 is denoted as R1, the radius of the shaft hole 110 is denoted as R3, and the maximum width of the permanent magnet 200 in the direction from the weight reduction hole 130 to the shaft hole 110 is denoted as Lm.

[0184] By defining the relationship between Lm, Wm, R1, and R3, we can ensure that Lm × Wm < R1. 2 -R3 2 This balances the motor's rotational inertia and torque ripple.

[0185] Optionally, a cross-section is taken of the permanent magnet 200 along an axial direction perpendicular to the shaft hole 110. In this cross-section, the outline of the permanent magnet 200 includes an arc segment 210, two straight segments 220, and a connecting segment. The arc segment 210 connects the two straight segments 220, and the connecting segment also connects the two straight segments 220. The arc segment 210 and the connecting segment are arranged at intervals along the direction from the permanent magnet 200 to the shaft hole 110. The two straight segments 220 are arranged circumferentially along the shaft hole 110, the arc segment 210 is arranged at intervals with the rotor core 100, and the connecting segment is fitted to the rotor core 100. The connecting segment includes any one or a combination of the following: a straight segment, an arc segment, and a broken line segment.

[0186] In some embodiments, optionally, Lm, Wm, R1, and R3 satisfy: 0.05 ≤ Lm × Wm / (R1 2 -R3 2 )≤0.2.

[0187] In this embodiment, the matching relationship of parameters Lm, Wm, R1, and R3 is further defined.

[0188] Specifically, Lm, Wm, R1, and R3 satisfy: 0.05 ≤ Lm × Wm / (R1 2 -R3 2 )≤0.2. That is, when (Lm×Wm) and (R1) 2 -R3 2 When the ratio of ) is in the range of 0.05 to 0.2, both the rotational inertia and torque ripple of the motor are taken into account.

[0189] If Lm×Wm / (R1) 2 -R3 2 If the value is less than 0.05, then the volume of the permanent magnet 200 is too small, which will affect the distribution of the magnetic field and cannot effectively guarantee the performance of the motor.

[0190] If Lm×Wm / (R1) 2 -R3 2If the value is greater than 0.2, then the volume of the permanent magnet 200 is relatively large. If too much material is used in the permanent magnet 200, the weight of the rotor 10 will increase, which will increase the moment of inertia of the motor.

[0191] Optionally, Lm×Wm / (R1) 2 -R3 2 )=0.06、Lm×Wm / (R1 2 -R3 2 )=0.07、Lm×Wm / (R1 2 -R3 2 =0.08, Lm×Wm / (R1) 2 -R3 2 )=0.09、Lm×Wm / (R1 2 -R3 2 =0.1, Lm×Wm / (R1) 2 -R3 2 )=0.11、Lm×Wm / (R1 2 -R3 2 =0.12, Lm×Wm / (R1) 2 -R3 2 =0.13, Lm×Wm / (R1) 2 -R3 2 =0.14, Lm×Wm / (R1) 2 -R3 2 =0.15, Lm×Wm / (R1) 2 -R3 2 =0.16, Lm×Wm / (R1) 2 -R3 2 )=0.17、Lm×Wm / (R1 2 -R3 2 ) = 0.18 and Lm×Wm / (R1 2 -R3 2 ) = 0.19, etc., which will not be listed here one by one.

[0192] In some embodiments, optionally, such as Figure 1 and Figure 3 As shown, the rotor 10 also includes a shaft 300.

[0193] The shaft body 300 is inserted into the shaft hole 110. The shaft body 300 has a cylindrical structure and the wall thickness of the shaft body 300 is less than or equal to 4mm.

[0194] In this embodiment, the structure of the rotor 10 is further defined, and the rotor 10 also includes a shaft 300, which passes through the shaft hole 110.

[0195] The shaft 300 has a cylindrical structure, meaning it is hollow. The space enclosed by the inner circumferential wall of the shaft 300 is used for assembly with other components of the motor. By limiting the range of the wall thickness of the shaft 300, ensuring that the wall thickness is less than or equal to 4mm, the weight of the rotor 10 can be reduced while maintaining the structural strength of the shaft 300, which helps to reduce the rotational inertia of the motor.

[0196] Optionally, the wall thickness of the shaft 300 includes 3.9mm, 3.8mm, 3.7mm, 3.6mm, 3.5mm, 3.4mm, 3.3mm, 3.2mm, 3.1mm and 3mm, etc., which will not be listed here.

[0197] In some embodiments, p = 5.

[0198] In this embodiment, the specific range of values ​​for the pole logarithm is defined. Specifically, p = 5.

[0199] An electric motor according to some embodiments of this application includes: a stator; and a rotor 10 as described in any of the above embodiments, the stator surrounding the rotor 10, and the rotor 10 being rotatable relative to the stator.

[0200] The motor provided in this application includes a stator and a rotor 10 of any of the above embodiments. Since it includes a rotor 10 as described in any of the above embodiments, it has all the beneficial effects of the rotor 10 described above, which will not be described one by one here.

[0201] A braking system according to some embodiments of this application includes: a motor as described in the above embodiments.

[0202] The braking system provided in this application includes a motor as described in the above embodiments, and therefore has all the beneficial effects of the motor described above, which will not be described in detail here.

[0203] The motor in this application is a brake motor.

[0204] A vehicle according to some embodiments of the present application includes: a motor as described in the above embodiments; or a braking system as described in the above embodiments.

[0205] The vehicle provided in this application includes a motor as described in the above embodiments or a braking system as described in the above embodiments, and therefore has all the beneficial effects of the motor or braking system described above, which will not be described one by one here.

[0206] It is worth noting that the vehicle can be a new energy vehicle. New energy vehicles include pure electric vehicles, range-extended electric vehicles, hybrid electric vehicles, fuel cell electric vehicles, and hydrogen engine vehicles.

[0207] The vehicle can also be a gasoline-powered car.

[0208] This application has a reasonable structure for the rotor 10, which can reduce the rotational inertia of the motor and effectively suppress the vibration and noise of the motor.

[0209] Optionally, the rotor 10 includes a rotor core 100, a plurality of permanent magnets 200, and a shaft 300. The shaft 300 is placed within the shaft hole 110 of the rotor core 100. The plurality of permanent magnets 200 are distributed circumferentially along the rotor core 100. The outer peripheral wall of the rotor core 100 is provided with a plurality of first grooves 120, which are arranged at intervals along the circumferential direction of the shaft hole 110, with one first groove 120 between two adjacent permanent magnets 200. The rotor core 100 is provided with a plurality of weight-reducing holes 130, which are located between the shaft hole 110 and the outer peripheral wall of the rotor core 100.

[0210] The maximum distance from the center of the shaft hole 110 to the side of the permanent magnet 200 away from the rotor core 100 is R1; the minimum distance from a point on the wall of the weight reduction hole 130 to the outer peripheral wall of the rotor core 100 is L1; the minimum distance from the center of the shaft hole 110 to the wall of the weight reduction hole 130 is R2; the maximum width of the permanent magnet 200 in the direction from the weight reduction hole 130 to the shaft hole 110 is Lm; and the radius of the shaft hole 110 is R3. Wherein, 0.15 ≤ (R1 - R2 - Lm - L1) / (R1 - R3) ≤ 0.6.

[0211] Optionally, the rotor core 100 includes a plurality of rotor laminations 140, which are stacked. The first axial end face 142 of each rotor lamination 140 has a plurality of second grooves 146, and the second axial end face 144 of each rotor lamination 140 has a plurality of protrusions 148. In two adjacent rotor laminations 140, each protrusion 148 of one rotor lamination 140 is interference-fitted with one of the second grooves 146 of the other rotor lamination 140. In each rotor lamination 140, the number of protrusions 148 is 2×p, and the number of second grooves 146 is 2×p, where p is the number of pole pairs.

[0212] Optionally, the minimum distance from a point on the wall of the weight-reducing hole 130 to the center line 122 of the first groove is L2, and the center line 122 of the first groove passes through the center of the opening of the first groove 120 and the center of the bottom of the first groove 120. d is the thickness of the rotor lamination 140. Where d is the thickness of the rotor lamination 140. The maximum distance between any two points on the wall of the second groove 146 on the first axial end face 142 of the rotor lamination 140 is D1.

[0213] Wherein, 0≤(L2-D1 / 2-d) / (R2×sin(π / 2 / p))≤0.5.

[0214] Optionally, R2-R3≥d, L1≥d.

[0215] Optionally, the rotor core 100 is cross-sectioned along the axial direction perpendicular to the shaft hole 110, and the wall of the weight reduction hole 130 includes five hole segments 132 connected end to end.

[0216] Optionally, the center of the weight reduction hole 130 is located at the center of the magnetic pole, and the multiple hole segments 132 include a first hole segment 132a and a second hole segment 132b connected to each other. The distance from the connection point of the first hole segment 132a and the second hole segment 132b to the outer peripheral wall of the rotor core 100 is L1, and the included angle between the first hole segment 132a and the second hole segment 132b is a, wherein 50° < a < 100°.

[0217] Optionally, the shaft body 300 is a hollow shaft, and the wall thickness of the shaft body 300 is less than or equal to 4 mm.

[0218] Optionally, the cross-sectional shape of the first groove 120 is T-shaped. On the axial end face of the rotor core 100, the width of the bottom of the first groove 120 is L3, the distance from the opening of the first groove 120 to the bottom of the first groove 120 is L4, and the length of the portion of the outer peripheral wall of the rotor core 100 located between two adjacent first grooves 120 is L5. Wherein, 0.025 ≤ L3 × L4 / (L5 × (R1 - Lm - R3)) ≤ 0.08.

[0219] Optionally, a cross-section is taken of the permanent magnet 200 along the axial direction perpendicular to the shaft hole 110. In the cross-section, the outline of the permanent magnet 200 includes an arc segment 210, two straight segments 220, and a connecting segment. The two straight segments 220 are arranged circumferentially along the shaft hole 110. Along the direction from the permanent magnet 200 to the shaft hole 110, the arc segment 210 and the connecting segment are arranged at intervals. The arc segment 210 connects between the two straight segments 220, and the connecting segment connects between the two straight segments 220. The arc segment 210 is arranged at intervals with the rotor core 100, and the connecting segment is fitted to the rotor core 100. The maximum distance between the two straight segments 220 is denoted as Wm. 0.05≤Lm×Wm / (R1) 2 -R3 2 )≤0.2.

[0220] Optionally, the pole-log number p = 5.

[0221] like Figure 4 As shown, taking a 12-slot, 10-pole surface-mount permanent magnet motor as an example, let X = (R1 - R2 - Lm - L1) / (R1 - R3), where T* and J* are per-unit values. In related technologies, the motor rotor does not have weight-reduction holes 130. T* refers to the ratio of torque under different X values ​​to the torque of the motor in related technologies. J* refers to the ratio of moment of inertia under different X values ​​to the moment of inertia of the motor in related technologies. Figure 4It can be seen that when 0.15≤X≤0.6, the motor has a larger output torque and a lower moment of inertia, resulting in the highest cost-effectiveness.

[0222] The shaft 300 of the rotor 10 passes through the shaft hole 110. The weight-reducing hole 130 has the function of reducing weight. The first groove 120 is used to cooperate with the positioning member of the rotor 10 to limit the cooperation position of the multiple permanent magnets 200 and the rotor core 100 by the positioning member.

[0223] On the axial end face of the rotor core 100, the maximum distance from the center of the shaft hole 110 to the side of the permanent magnet 200 away from the rotor core 100 is denoted as R1; the minimum distance from the center of the shaft hole 110 to the wall of the weight reduction hole 130 is denoted as R2; the radius of the shaft hole 110 is denoted as R3; the maximum width of the permanent magnet 200 in the direction from the weight reduction hole 130 to the shaft hole 110 is denoted as Lm; and the minimum distance from a point on the wall of the weight reduction hole 130 to the outer peripheral wall of the rotor core 100 is denoted as L1. That is, the inner diameter of the rotor core 100 is 2 × R3.

[0224] The moment of inertia of the motor is related to the mass distribution of the rotor 10 and the position of the shaft 300. This application defines the relationship between R1, R2, R3, L1, and Lm to satisfy: R1-R2-Lm-L1 < R1-R3. This setting not only meets the requirements for effectively assembling the rotor core 100 and multiple permanent magnets 200, but also establishes a matching relationship between the shaft hole 110, the weight reduction hole 130, the first groove 120, and the position of the permanent magnets 200, thereby optimizing the mass distribution of the rotor 10 and the installation position of the shaft 300. This reduces the moment of inertia of the motor, lowers the starting difficulty of the motor, and ensures the performance of the motor.

[0225] Meanwhile, the combined structure of the defined shaft hole 110, weight reduction hole 130, first groove 120, and permanent magnet 200 can also adjust the direction of magnetic field lines, thereby regulating the magnetic field distribution. This avoids oversaturation and undersaturation regions in the magnetic flux density design, thus reducing torque pulsation and lowering motor operating noise.

[0226] Understandably, excessive weight of the rotor 10 increases the centrifugal load on the rotor 10, reduces the fatigue life of the rotor core 100, and increases the moment of inertia of the motor. Setting multiple weight-reducing holes 130 helps reduce the moment of inertia of the motor. Associating L1 with R1, R2, R3, and Lm links the position of the weight-reducing holes 130 with the position of the shaft hole 110, the position of the outer peripheral wall of the rotor core 100, and the position of the permanent magnet 200. The position of the weight-reducing holes 130 differs for shafts 300 with different outer diameters, rotor cores 100s of different sizes, and permanent magnets 200s of different sizes. If the weight-reducing holes 130 are placed too close to the shaft hole 110, it will increase the stress level on the inner side of the shaft hole 110. If the weight-reducing holes 130 are placed too close to the outer peripheral wall of the rotor core 100, it will affect the stress and magnetic circuit on the outer circumferential side of the rotor core 100, thus affecting the torque of the motor. Therefore, this application has a reasonable structure for the rotor 10, which balances reducing the rotational inertia of the motor and ensuring the performance of the motor.

[0227] In this application, the term "multiple" refers to two or more unless otherwise expressly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0228] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. The above descriptions are merely preferred 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, characterized in that, include: The rotor core has a shaft hole and a plurality of first grooves on its outer peripheral wall. The portion of the rotor core located between the shaft hole and the outer peripheral wall of the rotor core has a plurality of weight-reducing holes. The plurality of weight-reducing holes and the plurality of first grooves are arranged at intervals along the circumference of the shaft hole, and the shaft hole, the weight-reducing holes and the first grooves all penetrate the two axial end faces of the rotor core. Multiple permanent magnets are disposed on the outer peripheral wall of the rotor core. The multiple permanent magnets are arranged at circumferential intervals along the shaft hole, and a first groove is provided between any two adjacent permanent magnets. On the axial end face of the rotor core, the maximum distance from the center of the shaft hole to the side of the permanent magnet away from the rotor core is R1, the minimum distance from the center of the shaft hole to the wall of the weight reduction hole is R2, the radius of the shaft hole is R3, the maximum width of the permanent magnet in the direction from the weight reduction hole to the shaft hole is Lm, and the minimum distance from a point on the wall of the weight reduction hole to the outer peripheral wall of the rotor core is L1. Where R1-R2-Lm-L1<R1-R3.

2. The rotor according to claim 1, characterized in that, R1, R2, R3, L1, and Lm satisfy: 0.15≤(R1-R2-Lm-L1) / (R1-R3)≤0.

6.

3. The rotor according to claim 1 or 2, characterized in that, The portion of the rotor core located between two adjacent weight-reduction holes is positioned opposite to one of the first grooves.

4. The rotor according to claim 1 or 2, characterized in that, The rotor core includes multiple stacked rotor laminations, the first axial end face of the rotor laminations is provided with multiple second grooves, and the second axial end face of the rotor laminations is provided with multiple protrusions; In two adjacent rotor laminations, each of the protrusions of one rotor lamination is interference-fitted with a second groove of the other rotor lamination; The number of protrusions in the rotor lamination is 2×p, where p is the number of pole pairs.

5. The rotor according to claim 4, characterized in that, On the first axial end face of the rotor lamination, each second groove is arranged opposite to one of the first grooves. The minimum distance from a point on the wall of the weight reduction hole to the center line of the first groove is L2. The maximum distance between any two points on the wall of the second groove is D1. The thickness of the rotor lamination is d. The center line of the first groove passes through the center of the opening of the first groove and the center of the bottom of the first groove. Where L2-D1 / 2-d<R2×sin(π / 2 / p).

6. The rotor according to claim 5, characterized in that, L2, D1, d, R2, and p satisfy: 0 ≤ (L2 - D1 / 2 - d) / (R2 × sin(π / 2 / p)) ≤ 0.

5.

7. The rotor according to claim 6, characterized in that, R2, R3, d, and L1 satisfy: R2-R3≥d, L1≥d.

8. The rotor according to claim 1 or 2, characterized in that, On the axial end face of the rotor core, the wall of the weight reduction hole includes multiple hole segments connected end to end, and the extension directions of any two adjacent hole segments are different. The center of the weight reduction hole is located on the magnetic pole center line. The plurality of hole segments include a first hole segment and a second hole segment connected together. The distance from the connection point of the first hole segment and the second hole segment to the outer peripheral wall of the rotor core is L1. The included angle between the first hole segment and the second hole segment is a, wherein 50° < a < 100°.

9. The rotor according to claim 1 or 2, characterized in that, On the axial end face of the rotor core, the circumferential length of the opening of the first groove is less than the circumferential length of the bottom of the first groove, the width of the bottom of the first groove is L3, the distance from the opening of the first groove to the bottom of the first groove is L4, and the length of the portion of the outer peripheral wall of the rotor core located between two adjacent first grooves is L5. Where L3×L4<L5×(R1-Lm-R3).

10. The rotor according to claim 9, characterized in that, L3, L4, L5, R1, Lm, and R3 satisfy: 0.025≤L3×L4 / (L5×(R1-Lm-R3))≤0.

08.

11. The rotor according to claim 1 or 2, characterized in that, The permanent magnet is cross-sectioned along the axial direction perpendicular to the shaft hole. In the cross-section, the outline of the permanent magnet includes an arc segment and two straight segments. The arc segment is connected between the two straight segments. The two straight segments are arranged circumferentially along the shaft hole. The arc segment is spaced apart from the rotor core. The maximum distance between the two straight segments is Wm. Where Lm×Wm<R1 2 -R3 2 .

12. The rotor according to claim 11, characterized in that, Lm, Wm, R1, and R3 satisfy: 0.05 ≤ Lm × Wm / (R1 2 -R3 2 )≤0.

2.

13. The rotor according to claim 1 or 2, characterized in that, Also includes: A shaft body, which is inserted into the shaft hole, has a cylindrical structure and a wall thickness of less than or equal to 4 mm.

14. The rotor according to claim 4, characterized in that, p＝5。 15. An electric motor, characterized in that, include: stator; and The rotor as claimed in any one of claims 1 to 14, wherein the stator surrounds the rotor, and the rotor is rotatable relative to the stator.

16. A braking system, characterized in that, include: The motor as described in claim 15.

17. A vehicle, characterized in that, include: The motor as described in claim 15; or The braking system as described in claim 16.

Images