Rotor core and electric motor

Abstract

Provided in the embodiments of the present application is a rotor core. The rotor core comprises a rotor main body, flux barriers and permanent magnets, wherein the rotor main body comprises a plurality of rotor punching sheets which are stacked, each rotor punching sheet is configured in a ring shape, each rotor punching sheet is provided with a plurality of first groove groups at intervals in a circumferential direction, and each of the first groove groups comprises a pair of first grooves which are symmetrical about a D axis; the flux barriers are arranged at intervals between the pair of first grooves so as to form internal flux barriers on the rotor punching sheets between the inner ends of the pair of first grooves; and the permanent magnets are arranged in the first grooves, and each of the permanent magnets comprises a magnetic main body and an insulating layer, the insulating layer being arranged on the side of the magnetic main body close to the D axis. In the rotor core and an electric motor provided in the embodiments of the present application, an asymmetric air gap is generated between the magnetic main body and the first grooves, resulting in an uneven magnetic pull force that attracts the permanent magnets to the side close to a Q axis, so that the effect, on the flux barriers, of a centrifugal force generated by the permanent magnets during high-speed operation of the electric motor is reduced, thus improving the safety of the electric motor during high-speed operation.

Description

Rotor core and motor

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202311187480.2 and application date September 14, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the field of motor equipment, and in particular to a rotor core and a motor. Background Art

[0004] In recent years, with the rapid development of new energy, the safety requirements for motors operating at high speeds have become increasingly stringent. When a motor rotates at high speeds, the magnetic isolation bridge in the motor core is subjected to large centrifugal forces, which can easily cause the magnetic isolation bridge to break and damage.

[0005] The existing method of reducing the occurrence of fracture damage of the magnetic isolation bridge is usually to increase the width and strength of the magnetic isolation bridge, which increases the design difficulty and production cost of the motor punching.

[0006] How to reduce the centrifugal force on the magnetic isolation bridge, thereby reducing the risk of breakage and damage, has become a key issue in ensuring the safety of high-speed operation of the motor.

[0007] Summary of the Invention

[0008] In view of this, embodiments of the present application aim to provide a rotor core and a motor to solve the problem of large centrifugal forces borne by the magnetic bridge in the existing motor core. To achieve the above-mentioned purpose, a first aspect of embodiments of the present application provides a rotor core, comprising:

[0009] The rotor body includes a plurality of stacked rotor sheets, the rotor sheets being configured in an annular shape, the rotor sheets being provided with a plurality of first slot groups spaced apart along the circumferential direction, each of the first slot groups including a pair of first slots symmetrically arranged along the D axis;

[0010] A magnetic isolation bridge is provided between a pair of the first slots in each first slot group to form an internal magnetic isolation bridge on the rotor punching between inner ends of the pair of the first slots; and

[0011] A permanent magnet is arranged in the first slot of each of the stacked rotor punchings; wherein the permanent magnet includes a magnetic body and an insulating layer, and the insulating layer is arranged on a side of the magnetic body close to the D axis.

[0012] Furthermore, the first slot includes:

[0013] a receiving groove for accommodating the permanent magnet; and

[0014] A dovetail groove is connected to the placement groove, and two ends of the placement groove protrude from the two ends of the dovetail groove to form air grooves. The dovetail groove is used to fix the permanent magnet.

[0015] Furthermore, the cross section of the magnetic body is trapezoidal, and the long bottom side of the magnetic body is arranged on a side away from the D axis.

[0016] Furthermore, the insulating layer and the magnetic body are connected by bonding.

[0017] Furthermore, the insulating layer is a tetrafluoroethylene plate.

[0018] Furthermore, the rotor punching has a plurality of weight-reducing holes in the middle.

[0019] Furthermore, the weight-reducing holes are quadrilateral, triangle, ellipse or circle; and / or,

[0020] The weight-reducing hole is provided inside the magnetic isolation bridge; and / or,

[0021] The corresponding weight-reducing holes on each of the rotor punchings are connected to form an air-cooling channel.

[0022] Furthermore, the first groove is spaced apart from the outer circumferential edge of the rotor punching to form the magnetic isolation bridge of the outer circumferential edge.

[0023] Furthermore, the rotor body further includes a magnetic isolation reinforcement member, the rotor punching also has a second slot located between a pair of inner ends of the first slots, and the magnetic isolation reinforcement member is located in the second slot.

[0024] A second aspect of an embodiment of the present application provides a motor comprising any of the above-mentioned rotor cores.

[0025] The rotor core and motor of the embodiments of the present application have an insulating layer arranged on the side of the magnetic body close to the D-axis, which creates an asymmetric air gap between the magnetic body and the first slot, causing uneven magnetic pull on the magnetic body. The magnetic body is adsorbed on the side close to the Q-axis, so that the centrifugal force generated by the magnetic body during high-speed operation of the motor does not affect the D-axis, reducing the centrifugal force borne by the magnetic isolation bridge and improving the safety of the motor during high-speed operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic structural diagram of a rotor core provided in an embodiment of the present application;

[0027] FIG2 is a perspective view of an assembly process of a rotor core provided in an embodiment of the present application;

[0028] FIG3 is a partial view of a first slot of a rotor core provided by an embodiment of the present application;

[0029] FIG4 is a partial view of a first slot of a rotor core provided by an embodiment of the present application;

[0030] FIG5 is a perspective view of a permanent magnet of a rotor core provided in an embodiment of the present application;

[0031] FIG6 is a schematic structural diagram of a rotor core provided in an embodiment of the present application;

[0032] FIG7 is a schematic structural diagram of a rotor core provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0034] In the description of the embodiments of the present application, it should be noted that the terms "axis," "bottom," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the embodiments of the present application and to simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood in specific circumstances.

[0036] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "on" or "under" a second feature may mean that the first feature and the second feature are in direct contact, or the first feature and the second feature are in indirect contact through an intermediate medium.

[0037] In the description of this specification, the description with reference to the term "some embodiments" or the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are mutually inconsistent.

[0038] With the rapid development of new energy vehicle technology, the safety of drive motors for new energy vehicles during high-speed operation is becoming increasingly important. When the motor is running at high speed, the permanent magnets in the rotor core will apply a large centrifugal force to the magnetic isolation bridge, which can easily cause the magnetic isolation bridge to break and be damaged. Reducing the occurrence of breakage and damage to the magnetic isolation bridge is one of the important methods to improve the safety of the motor. At present, the safety of high-speed operation is usually ensured by enhancing the strength of the magnetic isolation bridge, such as increasing the width of the magnetic isolation bridge or using embedded structural parts. The existing structure fails to give full play to the structural characteristics of the permanent magnets in the rotor core to reduce the centrifugal force applied to the magnetic isolation bridge, resulting in the problems of difficulty in designing the magnetic isolation bridge, design redundancy and low material utilization when designing the rotor core.

[0039] In view of this, as shown in Figures 1 to 3, an embodiment of the present application provides a rotor core, including a rotor body 1, a magnetic isolation bridge 2 and a permanent magnet 3. The rotor body 1 includes a plurality of rotor punchings 10 stacked together, the rotor punchings 10 are configured in a ring shape, and the rotor punchings 10 are provided with a plurality of first slot groups 11 spaced apart along the circumferential direction, and each of the first slot groups 11 includes a pair of first slots 12 symmetrical along the D axis. The magnetic isolation bridge 2 is spaced apart between a pair of first slots 12 of each first slot group 11 to form an internal magnetic isolation bridge 2 on the rotor punching 10 between the inner ends of the pair of first slots 12. The permanent magnet 30 is arranged in the first slot 12 of each of the stacked rotor punchings. The permanent magnet 3 includes a magnetic body 31 and an insulating layer 32, and the insulating layer 32 is arranged on the side of the magnetic body 31 close to the D axis.

[0040] The D-axis is the direct axis and lies along the centerline of the rotor's magnetic poles. The Q-axis is the quadrature axis and lies along the perpendicular bisector between two adjacent magnetic poles. Specifically, as shown in Figure 1, the direction from the rotor sheet 10's axis toward the center of the first slot group 11 is the motor's D-axis, while the direction from the rotor sheet 10's axis toward the boundary between the two first slot groups 11 is the Q-axis.

[0041] Since the insulating layer 32 is arranged on the side of the magnetic body 31 close to the D axis, an asymmetric air gap is generated between the magnetic body 31 on the side close to the D axis and the first slot 12. The asymmetric air gap causes the magnetic body 31 to be subjected to uneven magnetic pulling force. The uneven magnetic pulling force adsorbs the magnetic body 31 on the side of the Q axis, reducing the centrifugal force applied by the magnetic body 31 to the magnetic isolation bridge 2 when the motor runs at high speed, reducing the fracture damage of the magnetic isolation bridge 2 when the motor runs at high speed, thereby improving the safety of the motor when running at high speed.

[0042] At the same time, the centrifugal force applied by the magnetic body 31 to the magnetic isolation bridge 2 when the motor is running at high speed is reduced. On the one hand, it can reduce the strength requirement of the rotor punching 10 for the magnetic isolation bridge 2, reduce the thickness of the magnetic isolation bridge 2, reduce the magnetic leakage of the permanent magnet 3, reduce the use of high-performance permanent magnetic materials, improve the utilization rate of materials, and reduce manufacturing costs; on the other hand, it can increase the mechanical speed of the motor, improve the power and power density of the motor, and achieve high-efficiency performance using the same materials.

[0043] In some embodiments, the first slot group 11 includes a pair of first slots 12 symmetrically arranged along the D axis. The pair of first slots 12 are inclined away from each other along the D axis, forming a V-shape with the opening facing away from the axis. The V-shaped arrangement of the first slots 12 provides a magnetic flux concentrating effect, widening the armature reaction quadrature-axis loop channel, allowing more magnetic flux to converge into the working air gap between the stator and rotor, thereby improving the motor's operating efficiency. Furthermore, the V-shaped arrangement of the first slots 12 reduces the DC component of the electromagnetic force in the rotor body 1, thereby reducing vibration and deformation during motor operation and improving the motor's safety during high-speed operation.

[0044] In some embodiments, as shown in FIG4 , the first slot 12 includes a placement slot 121 and a dovetail slot 122. The placement slot 121 is used to accommodate the permanent magnet 3. The dovetail slot 122 is connected to the placement slot 121. The two ends of the placement slot 121 protrude from the two ends of the dovetail slot 122 to form air slots 121a. The dovetail slot 122 is used to fix the permanent magnet 3. The dovetail slot 122 is located on the side of the first slot 12 close to the Q axis. The shape of the dovetail slot 122 is trapezoidal, with the long base of the trapezoid located close to the Q axis. The shape of the side of the permanent magnet 3 close to the Q axis is adapted to the dovetail slot 122, so that the permanent magnet 3 is tightly fitted with the dovetail slot 122 when entering the first slot 12. The trapezoidal shape of the dovetail slot 122 is used to limit the displacement of the permanent magnet 3, thereby reducing the centrifugal force applied by the permanent magnet 3 to the magnetic isolation bridge 2 during high-speed operation of the motor.

[0045] It should be noted that both ends of the seating slot 121 protrude beyond both ends of the dovetail slot 122 , and air slots 121 a are formed between the protruding portions and the permanent magnets placed inside the seating slot 121 . The air slots 121 a can reduce magnetic leakage and improve the working efficiency of the motor.

[0046] In some embodiments, as shown in Figures 3 and 5 , the cross-section of the magnetic body 31 is trapezoidal, with the long base of the magnetic body 31 positioned on the side away from the D-axis. The magnetic body 31 is made of a high-performance permanent magnet material, which can be an alloy permanent magnet material, a ferrite permanent magnet material, or a rare earth permanent magnet material, to provide the excitation magnetic field required for motor operation.

[0047] It should be noted that the long bottom side of the magnetic body 31 is set on the side away from the D axis, so that the contact area between the magnetic body 31 and the Q axis side is increased, the adsorption effect of the uneven magnetic pull on the magnetic body 31 is increased, and the magnetic body 31 is adsorbed on the side close to the Q axis, thereby reducing the influence of the magnetic body 31 on the D axis.

[0048] In some embodiments, as shown in Figures 3 and 5, the insulating layer 32 is connected to the magnetic body 31 by bonding. The insulating layer 32 is adapted to the side of the magnetic body 31 close to the D axis, so that the end faces of the insulating layer 32 and the magnetic body 31 are flush after being connected. Furthermore, an adhesive is applied to the side of the insulating layer 32 away from the D axis and / or the side of the magnetic body 31 close to the D axis, so that the insulating layer 32 is tightly connected to the magnetic body 31. Furthermore, a groove 311 is provided on the side of the magnetic body 31 close to the D axis, and the groove 311 contains an adhesive to enhance the connection strength between the insulating layer 32 and the magnetic body 31.

[0049] It should be noted that the shapes of the placement groove 121 and the dovetail groove 122 are adapted to the shape of the magnetic body 31 after the insulating layer 32 is bonded, so that after the permanent magnet 3 enters the first groove 12, the long bottom side and the short bottom side of the permanent magnet 3 are tightly fitted with the first groove 12.

[0050] Since the insulating layer 32 is connected to the magnetic body 31 by bonding, the air gap between the magnetic body 31 close to the D-axis and the first slot 12 is further increased, causing the magnetic resistance of the rotor punching 10 at the D-axis to increase, reducing the impact of the demagnetization current on the magnetic body 31, reducing the risk of irreversible demagnetization of the magnetic body 31 during operation, and improving the safety of the motor when running at high speed.

[0051] In some embodiments, as shown in FIG5 , the insulating layer 32 is a tetrafluoroethylene sheet. The thickness of the insulating layer 32 can be varied according to actual needs. The thicker the insulating layer 32, the larger the air gap between the magnetic body 31 and the first slot 12. This increases the uneven magnetic pull on the magnetic body 31 and strengthens the attraction of the magnetic body 31 to the Q axis, further reducing the centrifugal force exerted by the permanent magnet 3 on the magnetic isolation bridge 2 during high-speed operation of the motor.

[0052] In some embodiments, as shown in Figure 6 , the rotor sheet 10 has multiple lightening holes 21 in the middle. These holes not only reduce magnetic flux leakage and improve motor performance, but also reduce the weight of the rotor sheet 10 and increase material utilization. The holes 21 are symmetrically arranged, with the same number of holes 21 in each first slot group 11, ensuring structural strength at every location on the rotor sheet 10.

[0053] In some embodiments, as shown in FIG6 , a weight-reducing hole 21 is provided inside the magnetic isolation bridge 2. While ensuring the strength of the magnetic isolation bridge 2, the weight-reducing hole 21 can significantly reduce the thickness of the magnetic isolation bridge 2, improve the magnetic isolation performance of the magnetic isolation bridge 2, and enhance the working efficiency of the motor.

[0054] In some embodiments, as shown in Figures 2 and 6 , the weight-reducing holes 21 are quadrilateral, triangular, elliptical, or circular. Furthermore, the corresponding weight-reducing holes 21 on each rotor punching 10 are connected to form an air-cooling channel. When the rotor body 1 rotates, air passes through the air-cooling channel to cool the rotor, reducing the risk of rotor demagnetization due to excessive temperature and improving the safety of the motor during high-speed operation.

[0055] In some embodiments, as shown in FIG6 , the first slot 12 is spaced apart from the outer circumference of the rotor sheet 10 to form a magnetic isolation bridge 2 on the outer circumference. The magnetic isolation bridge 2 on the outer circumference is not affected by the magnetic body 31 and can be set to a relatively small thickness. The relatively small thickness allows the magnetic isolation bridge 2 to have an excellent magnetic isolation effect.

[0056] In some embodiments, as shown in Figure 7, the rotor body 1 further includes a reinforcing magnetic shield 23. The rotor sheet 10 also includes a second slot 22 located between the inner ends of a pair of first slots 12. The reinforcing magnetic shield 23 is located within the second slot 22. The reinforcing magnetic shield 23 is made of high-strength structural steel that is non-magnetic, enhancing the rotor's strength. Furthermore, the reinforcing magnetic shield 23 is shaped to match the second slot 22, ensuring a tight fit.

[0057] It should be noted that when the reinforcing magnetic isolation member 23 is not placed in the second slot 22, as shown in Figure 6, since the second slot 22 is located between the inner ends of a pair of first slots 12, it is equivalent to a weight-reducing hole 21, which reduces the thickness of the magnetic isolation bridge 2 between the first slots 12 on both sides, improves the magnetic isolation capacity of the magnetic isolation bridge 2, increases the utilization rate of the material, and improves the working efficiency of the motor.

[0058] On the other hand, an embodiment of the present application further provides a motor, comprising a rotor core of any one of the above items. The specific structure of the above core refers to the above embodiment. Since the motor selectively adopts all the technical solutions of the above embodiments, it at least has the corresponding beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0059] In the embodiment of the present application, the motor can be used in a car, such as a hybrid car or an electric car. It is understood that in other embodiments, the motor of this embodiment can also be used in other electrical appliances, such as a refrigerator or a washing machine.

[0060] The various embodiments / implementations provided in this application can be combined with each other without causing any contradiction.

[0061] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A rotor core, comprising: The rotor body comprises a plurality of rotor punchings stacked in layers, wherein the rotor punchings are configured in an annular shape, and the rotor punchings are provided with a plurality of first slot groups spaced apart in the circumferential direction, and each of the first slot groups comprises a pair of first slots symmetrically along the D axis; A magnetic isolation bridge is arranged between a pair of the first slots of each first slot group to form an internal magnetic isolation bridge on the rotor punching between the inner ends of the pair of the first slots; as well as A permanent magnet is arranged in the first slot of each of the stacked rotor punching sheets; wherein the permanent magnet includes a magnetic body and an insulating layer, and the insulating layer is arranged on a side of the magnetic body close to the D axis.

2. The rotor core according to claim 1, wherein the first slot comprises: A placement slot, used to accommodate the permanent magnet; as well as A dovetail groove is connected to the placement groove, two ends of the placement groove protrude from the two ends of the dovetail groove to form air grooves, and the dovetail groove is used to fix the permanent magnet. 3 . The rotor core according to claim 1 , wherein the cross section of the magnetic body is a trapezoid, and the long bottom side of the magnetic body is arranged on a side away from the D axis. 4 . The rotor core according to claim 1 , wherein the insulating layer and the magnetic body are connected by bonding. The rotor core according to claim 4 , wherein the insulating layer is a tetrafluoroethylene plate.

6. The rotor core according to claim 1, wherein a plurality of weight-reducing holes are provided in the middle of the rotor punching sheet.

7. The rotor core according to claim 6, wherein the weight-reducing holes are quadrilateral, triangular, elliptical or circular; and / or, The weight-reducing hole is provided inside the magnetic isolation bridge; and / or, The corresponding weight-reducing holes on each of the rotor punching sheets penetrate to form an air-cooling channel.

8. The rotor core according to claim 1, wherein the first slot is spaced apart from the outer circumferential edge of the rotor punching sheet to form the magnetic isolation bridge of the outer circumferential edge.

9. The rotor core according to claim 1, wherein the rotor body further comprises a magnetic reinforcing member, the rotor punching sheet further comprises a second slot located between a pair of inner ends of the first slots, and the magnetic reinforcing member is located in the second slot.

10. An electric motor, comprising the rotor core according to any one of claims 1 to 9.

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