A rotor assembly and electric machine

Abstract

This invention provides a rotor assembly and a motor. The rotor assembly includes a rotor core with a central shaft hole at its center. A weight-reducing hole is provided on the rotor core, and a connecting groove is provided between the weight-reducing hole and the central shaft hole. A rotating shaft is disposed in the central shaft hole, and a connecting member is also provided on the outer periphery of the rotating shaft. The connecting member has a first protrusion on its outer periphery, a portion of which extends into the connecting groove, such that the end of the first protrusion away from the connecting member is at a distance greater than 0 from the weight-reducing hole. That is, there is a portion of the connecting groove between the first protrusion and the weight-reducing hole that is not filled by the first protrusion. According to this invention, harmonic flux linkage paths can be effectively blocked, magnetomotive force harmonics can be reduced, motor torque pulsation can be reduced, and leakage flux can be reduced, solving the problem of large magnetomotive force harmonics leading to large motor torque pulsation in the prior art.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more specifically to a rotor assembly and a motor. Background Technology

[0002] Permanent magnet synchronous motors have advantages such as high efficiency, high power factor, and high torque density, and they are gradually replacing asynchronous motors with low efficiency and poor power factor in many applications.

[0003] The magnetic field of a permanent magnet synchronous motor is mainly generated by the rotor permanent magnets. To improve the motor's torque output capability, it is necessary to limit the leakage flux of the permanent magnets. In most cases, the motor limits the leakage flux by setting magnetic isolation bridges between the slots of the rotor permanent magnets.

[0004] The width of the magnetic isolation bridge has a significant impact on the leakage flux coefficient of the motor. Reducing the width of the magnetic isolation bridge can increase the magnetic flux density of the magnetic isolation bridge, thereby increasing the magnetic reluctance at the magnetic isolation bridge and reducing the leakage flux of the motor.

[0005] A smaller magnetic bridge size leads to reduced mechanical strength at the magnetic bridge, affecting the motor's lifespan. To address this issue, patent CN112713681A connects the magnetic slots and uses a non-magnetic material, such as stainless steel or iron-cobalt-nickel alloy, as a magnetic bridge in the connecting area. This limits magnetic leakage from the permanent magnets while solving the problem of poor mechanical strength at the magnetic bridge. Patent CN117639327B further improves this by using a central block to connect the rotor core and rotor shaft, enhancing the motor's ability to limit magnetic leakage. However, stainless steel has a high density and low thermal conductivity, making heat dissipation difficult. Furthermore, both of these solutions suffer from significant magnetomotive force harmonics, resulting in large torque ripple in the motor.

[0006] Because existing permanent magnet synchronous motors suffer from problems such as large magnetomotive force subharmonics, resulting in large motor torque pulsation, this invention studies and designs a rotor assembly and a motor. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the defect of large magnetomotive force subharmonics in the existing permanent magnet synchronous motor, which leads to large motor torque pulsation, thereby providing a rotor assembly and a motor.

[0008] To address the above problems, the present invention provides a rotor assembly comprising:

[0009] The rotor core has a central shaft hole at its center and a weight-reducing hole. A connecting groove is provided between the weight-reducing hole and the central shaft hole. A rotating shaft is provided in the central shaft hole, and a connecting member is provided on the outer periphery of the rotating shaft. The outer periphery of the connecting member has a first protrusion. A portion of the first protrusion extends into the connecting groove, such that the end of the first protrusion away from the connecting member is at a distance greater than 0 from the weight-reducing hole. That is, there is a section of the connecting groove between the first protrusion and the weight-reducing hole that is not filled by the first protrusion.

[0010] In some implementations...

[0011] The connecting groove extends along the radial direction of the rotor core, and the first protrusion also extends along the radial direction of the rotor core. The extension length of the connecting groove is greater than the extension length of the first protrusion.

[0012] In some implementations...

[0013] It also includes a magnetic steel groove, which is disposed on the rotor core. The magnetic steel groove is located radially outside the weight reduction hole along the radial direction of the rotor core and within the projection plane of the axial end face of the rotor core. The rotor core has a d-axis, and the d-axis passes through the weight reduction hole and the connecting groove in the radially inward direction of the rotor core.

[0014] In some implementations...

[0015] The minimum distance between the weight reduction hole and the magnetic groove is d3, where d3 > 1 mm, and the minimum distance between two adjacent weight reduction holes in the circumferential direction is d4, where d4 > 1 mm.

[0016] In some implementations...

[0017] It also includes a magnetic steel groove, which is disposed on the rotor core and is located in the projection plane of the axial end face of the rotor core. The rotor core has a q-axis, and the q-axis passes through the weight reduction hole and the connecting groove in the radially inward direction of the rotor core.

[0018] In some implementations...

[0019] Within the projection plane of the axial end face of the rotor core, the distance between the radial outer periphery of the weight reduction hole and the center of the rotor core is d2, the minimum distance between the magnet slot and the center of the rotor core is d1, and d2 > d1, and the minimum distance between the weight reduction hole and the magnet slot is greater than 1mm.

[0020] In some implementations...

[0021] The weight-reducing hole is a through hole extending from one axial end of the rotor core to the other axial end. The weight-reducing hole is a hollow structure and is not filled with any material. There are multiple weight-reducing holes, which are arranged at intervals along the circumferential direction of the rotor core. There are also multiple connecting slots, which are also arranged at intervals along the circumferential direction of the rotor core. The weight-reducing holes and the connecting slots are connected in a one-to-one correspondence.

[0022] In some implementations...

[0023] It also includes magnetic slots, which are disposed on the rotor core. There are two magnetic slots in the same pole. The d-axis of the rotor core passes through the position between the two magnetic slots in the same pole, and the q-axis of the rotor core passes through the position between the two magnetic slots between two adjacent poles.

[0024] The rotor core has 2P poles, the number of weight-reducing holes is also 2P, the number of connecting slots is also 2P, and the number of the first protrusions is also 2P.

[0025] In some implementations...

[0026] A first reinforcing rib is provided between the magnet slot and the outer circle of the rotor core. A second reinforcing rib is provided at the closest position between two adjacent magnet slots. The size of the first reinforcing rib is the distance between the magnet slot and the outer circle of the rotor, and the size of the first reinforcing rib is 0.7mm to 1mm. The size of the second reinforcing rib is the distance between two adjacent magnet slots, and the size of the second reinforcing rib is 0.7mm to 1mm.

[0027] In some implementations...

[0028] It also includes a second protrusion. The connector is an annular structure and is disposed in the central shaft hole. The inner circumference of the connector is also provided with the second protrusion. A keyway is provided on the outer circumferential wall of the rotating shaft. The second protrusion is inserted into the keyway.

[0029] In some implementations...

[0030] A third protrusion is connected to the first protrusion. The extension direction of the third protrusion is different from that of the first protrusion, and the two extension directions have an angle between (0° and 90°). A second connecting groove is also provided on the rotor core. The second connecting groove is connected to the first connecting groove, and the two extension directions have an angle between (0° and 90°). The third protrusion can be engaged in the second connecting groove.

[0031] In some implementations...

[0032] The third protrusion extends along the circumferential direction of the rotor core, the second connecting groove extends along the circumferential direction of the rotor core, and the extension length of the second connecting groove is greater than or equal to the extension length of the third protrusion.

[0033] In some implementations...

[0034] Multiple fin holes are provided on the outer periphery of the weight reduction hole. The multiple fin holes are spaced apart along the circumferential direction of the rotor core to form a fin hole structure for heat dissipation.

[0035] The present invention also provides an electric motor comprising the aforementioned rotor assembly.

[0036] The rotor assembly and motor provided by this invention have the following beneficial effects:

[0037] This invention effectively reduces weight by setting weight-reducing holes on the rotor core, which also reduces the motor's moment of inertia and improves its dynamic performance. A connecting groove is also provided, connecting the connecting groove to the weight-reducing holes and the central shaft hole. A connector is used to connect the rotating shaft and the rotor core. A first protrusion on the outer periphery of the connector can be inserted into the connecting groove, thus achieving the effect of the rotating shaft rotating, driving the connector to rotate, and ultimately driving the rotor core to rotate as a whole. The first protrusion does not fully extend to the weight-reducing hole; the end of the first protrusion furthest from the connector is at a distance greater than 0 from the weight-reducing hole. That is, there is a section of the connecting groove between the first protrusion and the weight-reducing hole that is not filled by the first protrusion. Therefore, this part of the connecting groove can effectively block harmonic flux paths, reduce magnetomotive force second harmonics, increase the motor's average torque, reduce torque pulsation, and reduce leakage flux. This effectively solves the problem of large magnetomotive force second harmonics in existing permanent magnet synchronous motors, which leads to large motor torque pulsation, and also solves the problem of large leakage flux in permanent magnet motors. Attached Figure Description

[0038] Figure 1 This is a top view of the rotor assembly of the present invention;

[0039] Figure 2 This is a top view of the rotor core of the present invention;

[0040] Figure 3 This is a structural diagram of the connector of the present invention;

[0041] Figure 4 This is a structural diagram of the rotating shaft of the present invention;

[0042] Figure 5 This is a top view of an alternative embodiment of the rotor assembly of the present invention (the weight reduction hole is located on the q-axis);

[0043] Figure 6 This is a structural diagram of the "I"-shaped connector of the present invention (including the third protrusion);

[0044] Figure 7 This is a structural diagram of the connector of the present invention with fewer than 2p protrusions;

[0045] Figure 8 This is a structural diagram of the rotor core of the present invention with fin holes provided on the weight reduction holes;

[0046] Figure 9 This is a motor magnetic field line cloud diagram of the rotor assembly weight reduction hole of the present invention located on the d-axis;

[0047] Figure 10 This is a magnetic field line cloud diagram of the motor for the rotor assembly weight reduction hole of the present invention located on the q-axis;

[0048] Figure 11 This is a magnetic field cloud diagram of a motor with a rotor assembly without weight reduction holes and connecting slots in the existing technology.

[0049] Figure 12 This is a torque pulsation histogram comparing the two schemes of the present invention with the prior art.

[0050] The reference numerals in the attached figures are as follows:

[0051] 1. Rotor core; 2. Central shaft hole; 3. Weight reduction hole; 4. Connecting groove; 5. Rotating shaft; 6. Connecting piece; 7. First protrusion; 8. Magnet groove; 9. First reinforcing rib; 10. Second reinforcing rib; 11. Second protrusion; 12. Keyway; 13. Third protrusion; 14. Second connecting groove; 15. Fin hole. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0054] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0055] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0056] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0057] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0058] like Figure 1-12 As shown, the present invention provides a rotor assembly comprising:

[0059] The rotor core 1 has a central shaft hole 2 at its center and a weight reduction hole 3. A connecting groove 4 is provided between the weight reduction hole 3 and the central shaft hole 2. A rotating shaft 5 is provided in the central shaft hole 2. A connecting member 6 is also provided on the outer periphery of the rotating shaft 5. The outer periphery of the connecting member 6 has a first protrusion 7. A portion of the structure of the first protrusion 7 extends into the connecting groove 4, such that the end of the first protrusion 7 away from the connecting member 6 is at a distance greater than 0 from the weight reduction hole 3. That is, there is a section of the connecting groove 4 between the first protrusion 7 and the weight reduction hole 3 that is not filled by the first protrusion 7.

[0060] This invention, through the aforementioned weight-reduction hole structure on the rotor core, effectively reduces weight and decreases the motor's moment of inertia, improving its dynamic performance. It also includes a connecting groove that connects the connecting groove to the weight-reduction hole and the central shaft hole. A connector links the rotating shaft to the rotor core. The first protrusion on the outer periphery of the connector can be inserted into the connecting groove, allowing the rotating shaft to rotate, which in turn drives the connector to rotate, thus rotating the rotor core as a whole. The first protrusion does not fully extend to the weight-reduction hole; the end of the first protrusion furthest from the connector is at a distance greater than 0 from the weight-reduction hole. This means there is a portion of the connecting groove between the first protrusion and the weight-reduction hole that is not filled by the first protrusion. Therefore, this portion of the connecting groove can effectively block harmonic flux paths, reduce magnetomotive force harmonics, increase the motor's average torque, reduce torque pulsation, and reduce leakage flux. This effectively solves the problem of large magnetomotive force harmonics leading to large torque pulsation in existing permanent magnet synchronous motors, and also addresses the problem of large leakage flux in permanent magnet motors.

[0061] The actual magnetic flux path of the motor in this invention is as follows: the main magnetic flux path is: rotor permanent magnet → air gap → stator teeth → stator yoke → stator teeth → air gap → rotor permanent magnet at the other pole. In addition to the main magnetic circuit, there are also harmonic flux linkages in the motor, which are far from the main magnetic circuit. These linkages bring abundant subharmonics to the motor, resulting in additional eddy current losses in the rotor permanent magnet and torque pulsation.

[0062] To block the harmonic flux path, the present invention adds weight reduction holes to the rotor and sets a connecting groove between the weight reduction holes and the inner circle of the rotor. Figures 9-12 The diagrams show the distribution of the motor's magnetic flux lines and the comparison of torque ripple when the weight-reduction holes are present on the d-axis, q-axis, and without weight-reduction holes. With other conditions remaining constant, compared to the motor torque ripple without weight-reduction holes and connecting slots, the torque ripple of the two solutions in this invention is reduced by approximately 20%.

[0063] In some implementations...

[0064] The connecting groove 4 extends along the radial direction of the rotor core 1, and the first protrusion 7 also extends along the radial direction of the rotor core 1. The extension length of the connecting groove 4 is greater than the extension length of the first protrusion 7.

[0065] This is a preferred structural form of the connecting groove and the first protrusion of the present invention, that is, both extend along the radial direction of the rotor core, but the extension length of the connecting groove is greater than the extension length of the first protrusion, so that the section on the radially outer side of the connecting groove, that is, the section communicating with the weight reduction hole, does not have the first protrusion extending into it. This can effectively utilize the hollow section of the connecting groove to block the harmonic flux path, reduce the magnetomotive force second harmonic, increase the average torque of the motor, reduce the torque pulsation of the motor, reduce leakage flux, and improve the effect of reducing torque pulsation and resisting leakage flux.

[0066] In some implementations...

[0067] It also includes a magnetic steel groove 8, which is disposed on the rotor core 1. The magnetic steel groove 8 is located radially outside the weight reduction hole 3 along the radial direction of the rotor core 1. In the projection plane of the axial end face of the rotor core 1, the rotor core 1 has a d-axis, and the d-axis passes through the weight reduction hole 3 and the connecting groove 4 in the radially inward direction of the rotor core 1.

[0068] This is a preferred structural form of the main embodiment of the present invention, in which both the weight-reducing hole and the connecting groove are disposed on the radially inner side of the d-axis, so that the d-axis passes through the weight-reducing hole and the connecting groove in sequence. Figures 9-12 The diagrams show the distribution of the motor's magnetic field lines and the comparison results of torque ripple when the d-axis has a weight-reduction hole, the q-axis has a weight-reduction hole, and the motor does not have a weight-reduction hole. With other conditions remaining unchanged, compared to the prior art motor without weight-reduction holes and connecting slots, the torque ripple of the main embodiment of this invention is reduced by approximately 20%, improving the effect of reducing torque ripple and preventing magnetic leakage.

[0069] Preferably,

[0070] Within the projection plane of the axial end face of the rotor core 1, the weight reduction hole 3 has a first center line extending in the radial direction of the rotor core 1, and the weight reduction hole 3 is symmetrically arranged with respect to the first center line. The connecting groove 4 has a second center line extending in the radial direction of the rotor core 1, and the connecting groove 4 is symmetrically arranged with respect to the second center line. The first center line coincides with the second center line and coincides with the d-axis.

[0071] In some implementations...

[0072] The minimum distance between the weight reduction hole 3 and the magnetic groove 8 is d3, where d3 > 1 mm, and the minimum distance between two circumferentially adjacent weight reduction holes 3 is d4, where d4 > 1 mm.

[0073] This invention aims to isolate harmonic flux linkage by adding weight-reducing holes to the rotor and setting connecting slots between the weight-reducing holes and the inner circle of the rotor. If the distance between the weight-reducing holes and the magnet slots is too small, the mechanical strength between them will decrease, thereby reducing the life of the laminations. Therefore, the width at this location should meet the structural strength requirements, and the minimum distance d3 between the weight-reducing holes and the magnet slots should be greater than 1 mm. When the weight-reducing holes are located on the d-axis, the minimum distance d4 between the weight-reducing holes should also be greater than 1 mm.

[0074] In some implementations...

[0075] It also includes a magnetic steel groove 8 (with a permanent magnet inside to provide a magnetic field for the motor), the magnetic steel groove 8 is disposed on the rotor core 1, in the projection plane of the axial end face of the rotor core 1, the rotor core 1 has a q-axis, and the q-axis passes through the weight reduction hole 3 and the connecting groove 4 in the radial inward direction of the rotor core 1.

[0076] This is a preferred structural form of an alternative embodiment of the present invention, wherein both the weight-reducing hole and the connecting groove are disposed radially inside the q-axis, such that the q-axis passes through the weight-reducing hole and the connecting groove in sequence. Figures 9-12 The diagrams show the distribution of the motor's magnetic field lines and the comparison results of torque ripple when the d-axis has a weight-reduction hole, the q-axis has a weight-reduction hole, and the motor does not have a weight-reduction hole. With other conditions remaining unchanged, compared to the prior art motor without weight-reduction holes and connecting slots, the torque ripple of the main embodiment of this invention is reduced by approximately 20%, improving the effect of reducing torque ripple and preventing magnetic leakage.

[0077] Preferably,

[0078] Within the projection plane of the axial end face of the rotor core, the weight reduction hole has a first center line extending in the radial direction of the rotor core, and the weight reduction hole is symmetrically arranged with respect to the first center line. The connecting groove has a second center line extending in the radial direction of the rotor core, and the connecting groove is symmetrically arranged with respect to the second center line. The first center line coincides with the second center line and coincides with the q-axis.

[0079] In some implementations...

[0080] Within the projection plane of the axial end face of the rotor core 1, the distance between the radial outer periphery of the weight reduction hole 3 and the center of the rotor core 1 is d2, the minimum distance between the magnet slot 8 and the center of the rotor core 1 is d1, and d2 > d1, and the minimum distance between the weight reduction hole 3 and the magnet slot 8 is greater than 1mm.

[0081] When the weight reduction hole is located on the q-axis, this invention should ensure that the structural strength of the minimum connection between the weight reduction hole and the rotor magnet slot meets the requirements, and the minimum connection distance should be greater than 1mm.

[0082] In this invention, the d-axis is generally defined as the magnetization direction of the permanent magnet, and the q-axis is defined as the perpendicular magnetization direction. When the weight reduction hole is located on the q-axis, as the distance d2 between the weight reduction hole and the rotor center increases, it gets closer and closer to the rotor magnet slot. As the distance continues to increase, the weight reduction hole connects with the magnet slot, which will lead to a decrease in the structural strength of the rotor. Therefore, it is necessary to limit the distance between the magnet slot and the weight reduction hole. This invention, by setting d2 > d1 and the minimum distance between the weight reduction hole 3 and the magnet slot 8 to be greater than 1 mm, can maximize the reduction of torque pulsation while preventing it from affecting the structural strength of the rotor.

[0083] In some implementations...

[0084] The weight-reducing hole 3 is a through hole that extends from one axial end of the rotor core 1 to the other axial end. The weight-reducing hole 3 is a hollow structure and is not filled with any material. There are multiple weight-reducing holes 3, which are arranged at intervals along the circumferential direction of the rotor core 1. There are also multiple connecting slots 4, which are also arranged at intervals along the circumferential direction of the rotor core 1. The weight-reducing holes 3 and the connecting slots 4 are connected in a one-to-one correspondence.

[0085] This is the preferred structural form of the weight-reducing holes of the present invention. By setting them as hollow and unfilled structures, the weight of the rotor core can be reduced, the moment of inertia can be reduced, the dynamic performance of the motor can be improved, and gas can be introduced into the interior to cool the rotor and improve heat dissipation performance. The arrangement of multiple weight-reducing holes and multiple connecting slots can improve the weight reduction and heat dissipation effect of the rotor core in the circumferential direction, and improve the reduction of torque pulsation in the circumferential direction, improve the average torque, and reduce leakage flux.

[0086] In some implementations...

[0087] It also includes magnetic steel slots 8, which are disposed on the rotor core 1. There are two magnetic steel slots 8 in the same pole. The d-axis of the rotor core 1 passes through the position between the two magnetic steel slots 8 in the same pole, and the q-axis of the rotor core 1 passes through the position between the two magnetic steel slots 8 between two adjacent poles.

[0088] The rotor core 1 has 2P poles, the weight reduction holes 3 also have 2P number, the connecting grooves 4 also have 2P number, and the first protrusions 7 also have 2P number.

[0089] By setting the number of weight-reducing holes, connecting slots, and first protrusions to be equal to the number of rotor core poles 2P, the present invention can achieve weight reduction, heat dissipation, reduced torque pulsation, and reduced magnetic leakage at each pole of the rotor core, thereby improving the reduction of air gap harmonic magnetic flux density and reducing the torque pulsation and vibration noise of the motor.

[0090] To address the shortcomings of the existing technology, this invention proposes a magnetic isolation structure for a permanent magnet synchronous motor, comprising rotor laminations, a rotor, and a motor. The motor constructed from these rotor laminations exhibits advantages such as high efficiency, high torque density, high power factor, and low torque ripple. The specific implementation is as follows:

[0091] Figure 1 This is the assembly drawing of the motor rotor, which includes: rotor core 1, connecting parts 6, and rotating shaft 5.

[0092] Figure 2 The rotor lamination structure features a rotor inner circle, a rotor outer circle, p pairs of magnet slots, and 2p weight-reduction holes on the rotor d-axis. The weight-reduction holes are connected to the rotor inner circle by connecting slots.

[0093] In some implementations...

[0094] A first reinforcing rib 9 is provided between the magnet slot 8 and the outer circle of the rotor core 1. A second reinforcing rib 10 is provided at the closest position between two adjacent magnet slots 8. The size of the first reinforcing rib 9 is the distance between the magnet slot 8 and the outer circle of the rotor, and the size of the first reinforcing rib 9 is 0.7mm to 1mm. The size of the second reinforcing rib 10 is the distance between two adjacent magnet slots 8, and the size of the second reinforcing rib 10 is 0.7mm to 1mm.

[0095] This invention Figure 2 Each magnet slot group consists of two magnet slots, each containing a first air slot, a second air slot, and a permanent magnet slot. Figure 2 Taking p=10 as an example, the rotor laminations have 10 sets of magnet slots, with 20 first air slots, 20 second air slots, and 20 permanent magnet slots each. A first reinforcing rib is provided between the air slots and the outer circumference of the rotor. The width of the reinforcing rib should be between 0.7mm and 1mm. Its purpose is to limit magnetic leakage by saturating the magnetic flux at this location, thereby increasing the average torque of the motor. The smaller the width, the better it limits magnetic leakage. However, a smaller width will lead to poorer mechanical strength at this location, shortening the motor's service life.

[0096] The shape of the magnetic steel groove of the present invention is not limited to V-shape, but also includes U-shape, C-shape, etc., and the number of layers is not limited to one layer.

[0097] The purpose of the second reinforcing rib placed between the air slots in this invention is also to limit magnetic leakage by saturating the magnetic flux at that location, thereby increasing the average torque of the motor. To resolve the contradiction between limiting magnetic leakage and improving mechanical strength, this invention proposes connecting the two second air slots to form a single air slot, and placing a non-magnetic material there. This limits magnetic leakage while ensuring structural strength at that location. However, if stainless steel is chosen, its high density and low thermal conductivity make heat dissipation difficult for the motor. If aluminum alloy is chosen, its structural strength is even worse, and to prevent material detachment, the material is shaped like an "I".

[0098] In some implementations...

[0099] It also includes a second protrusion 11. The connector 6 has an annular structure. The connector 6 is disposed in the central shaft hole 2. The inner circumference of the connector 6 is also provided with the second protrusion 11. The outer peripheral wall of the rotating shaft 5 is provided with a keyway 12. The second protrusion 11 is inserted into the keyway 12.

[0100] The present invention enables the second protrusion protruding from the inner circumference of the connector to engage with the keyway on the rotating shaft, thereby achieving the effect of the connector and the rotating shaft rotating as a whole, and the rotor core rotating as a whole with the connector and the rotating shaft.

[0101] The connector of the present invention is preferably made of a non-magnetic material and includes a first protrusion and a second protrusion. The first protrusion mates with the rotor connecting groove, and its number is the same as the number of weight-reduction holes, which is 2p, for connecting the rotor core and the connector. The second protrusion mates with the rotor shaft keyway for connecting the rotor core and the shaft. The shaft of the present invention preferably includes two keyways that mesh with the connector, allowing synchronous rotation with the rotor core via the connector.

[0102] In some implementations...

[0103] A third protrusion 13 is connected to the first protrusion 7. The extension direction of the third protrusion 13 is different from the extension direction of the first protrusion 7, and the two extension directions have an angle between (0° and 90°). A second connecting groove 14 is also provided on the rotor core 1. The second connecting groove 14 is connected to the connecting groove 4, and the two extension directions have an angle between (0° and 90°). The third protrusion 13 can be engaged in the second connecting groove 14.

[0104] By providing the third protrusion as described above, the present invention can further improve the tightness of the connection between the connector and the rotor core by engaging with the connecting groove two provided on the rotor core, thus preventing the two from coming loose during rotation.

[0105] To improve the fit between the rotor core and the connector, the connector is configured in an "I" shape or other shapes via a first protrusion and a third protrusion. Since this design achieves magnetic isolation solely through the air portion of the connecting groove, the number of the first protrusions on the connector does not need to be 2p.

[0106] In some implementations...

[0107] The third protrusion 13 extends along the circumferential direction of the rotor core 1, the second connecting groove 14 extends along the circumferential direction of the rotor core 1, and the extension length of the second connecting groove 14 is greater than or equal to the extension length of the third protrusion 13.

[0108] This is a preferred structural form of the third protrusion of the present invention, which can be integrated with the first protrusion to further securely limit the fit between the connector and the rotor core, and further prevent the connector from coming out of the rotor core.

[0109] In some implementations...

[0110] The outer periphery of the weight reduction hole 3 is provided with a plurality of fin holes 15, which are spaced apart along the circumferential direction of the rotor core 1 to form a fin hole structure for heat dissipation.

[0111] The present invention also improves heat dissipation by using multiple finned holes arranged around the weight reduction holes to allow gas to pass through, while increasing the flow area at the finned holes.

[0112] To improve the rotor's heat dissipation capacity and reduce the temperature rise of the permanent magnet, the rotor weight reduction holes can be used as ventilation holes, and multiple fins can be installed here to enhance the heat dissipation effect.

[0113] The present invention also provides an electric motor comprising the aforementioned rotor assembly.

[0114] This invention provides a magnetic shielding structure with weight-reducing holes and connecting slots, which can reduce air gap harmonic magnetic flux density, reduce motor torque pulsation and vibration noise, and solve the problem of large magnetic leakage in permanent magnet motors; it can also reduce rotor weight and improve motor dynamic performance.

[0115] This invention connects the rotor core and rotor shaft through the intermediate connector, reducing rotor weight and improving motor dynamic performance; the weight-reducing holes also improve the rotor's heat dissipation capacity, reduce permanent magnet temperature, and enhance permanent magnet performance.

[0116] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A rotor assembly, characterized in that: include: The rotor core (1) has a central shaft hole (2) at its center position. The rotor core (1) is provided with a weight reduction hole (3). A connecting groove (4) is provided between the weight reduction hole (3) and the central shaft hole (2). A rotating shaft (5) is provided in the central shaft hole (2). A connecting member (6) is also provided on the outer periphery of the rotating shaft (5). The outer periphery of the connecting member (6) has a first protrusion (7). Part of the structure of the first protrusion (7) extends into the connecting groove (4), so that the end of the first protrusion (7) away from the connecting member (6) is at a distance greater than 0 from the weight reduction hole (3). That is, there is a part of the connecting groove (4) that is not filled by the first protrusion (7) between the first protrusion (7) and the weight reduction hole (3). The extension direction of the connecting groove (4) is along the radial direction of the rotor core (1), and the extension direction of the first protrusion (7) is also along the radial direction of the rotor core (1). The extension length of the connecting groove (4) is greater than the extension length of the first protrusion (7).

2. The rotor assembly according to claim 1, characterized in that: It also includes a magnetic steel groove (8), which is disposed on the rotor core (1). The magnetic steel groove (8) is located on the radial side of the weight reduction hole (3) along the radial direction of the rotor core (1). In the projection plane of the axial end face of the rotor core (1), the rotor core (1) has a d-axis, and the d-axis passes through the weight reduction hole (3) and the connecting groove (4) in the radial inward direction of the rotor core (1).

3. The rotor assembly according to claim 2, characterized in that: The minimum distance between the weight reduction hole (3) and the magnetic groove (8) is d3, where d3 > 1 mm, and the minimum distance between two adjacent weight reduction holes (3) in the circumferential direction is d4, where d4 > 1 mm.

4. The rotor assembly according to claim 1, characterized in that: It also includes a magnetic steel groove (8), which is disposed on the rotor core (1). In the projection plane of the axial end face of the rotor core (1), the rotor core (1) has a q-axis, and the q-axis passes through the weight reduction hole (3) and the connecting groove (4) in the radial inward direction of the rotor core (1).

5. The rotor assembly according to claim 4, characterized in that: In the projection plane of the axial end face of the rotor core (1), the distance between the radial outer periphery of the weight reduction hole (3) and the center of the rotor core (1) is d2, the minimum distance between the magnet slot (8) and the center of the rotor core (1) is d1, and d2 > d1, and the minimum distance between the weight reduction hole (3) and the magnet slot (8) is greater than 1mm.

6. The rotor assembly according to claim 1, characterized in that: The weight-reducing hole (3) is a through hole that extends from one axial end of the rotor core (1) to the other axial end. The weight-reducing hole (3) is a hollow structure and is not filled with solid material. There are multiple weight-reducing holes (3), which are arranged at intervals along the circumferential direction of the rotor core (1). There are also multiple connecting slots (4), which are also arranged at intervals along the circumferential direction of the rotor core (1). The weight-reducing holes (3) and the connecting slots (4) are connected in a one-to-one correspondence.

7. The rotor assembly according to claim 6, characterized in that: It also includes magnetic steel slots (8), which are disposed on the rotor core (1). There are two magnetic steel slots (8) in the same pole. The d-axis of the rotor core (1) passes through the position between the two magnetic steel slots (8) in the same pole, and the q-axis of the rotor core (1) passes through the position between the two magnetic steel slots (8) between two adjacent poles. The rotor core (1) has 2P poles, the number of weight reduction holes (3) is also 2P, the number of connecting grooves (4) is also 2P, and the number of the first protrusions (7) is also 2P.

8. The rotor assembly according to claim 7, characterized in that: A first reinforcing rib (9) is provided between the magnetic steel groove (8) and the outer circle of the rotor core (1). A second reinforcing rib (10) is provided at the closest position between two adjacent magnetic steel grooves (8). The size of the first reinforcing rib (9) is the distance between the magnetic steel groove (8) and the outer circle of the rotor. The size of the first reinforcing rib (9) is 0.7mm~1mm. The size of the second reinforcing rib (10) is the distance between two adjacent magnetic steel grooves (8). The size of the second reinforcing rib (10) is 0.7mm~1mm.

9. The rotor assembly according to claim 1, characterized in that: It also includes a second protrusion (11), the connector (6) is an annular structure, the connector (6) is disposed in the central shaft hole (2), and the inner circumference of the connector (6) is also provided with the second protrusion (11), and a keyway (12) is provided on the outer circumferential wall of the rotating shaft (5), and the second protrusion (11) is inserted into the keyway (12).

10. The rotor assembly according to claim 1, characterized in that: A third protrusion (13) is connected to the first protrusion (7). The extension direction of the third protrusion (13) is different from that of the first protrusion (7), and the extension directions of the two have an angle between (0, 90°). A second connecting groove (14) is also provided on the rotor core (1). The second connecting groove (14) is connected to the connecting groove (4), and the extension directions of the two have an angle between (0, 90°). The third protrusion (13) can be locked in the second connecting groove (14).

11. The rotor assembly according to claim 10, characterized in that: The third protrusion (13) extends along the circumferential direction of the rotor core (1), the second connecting groove (14) extends along the circumferential direction of the rotor core (1), and the extension length of the second connecting groove (14) is greater than or equal to the extension length of the third protrusion (13).

12. The rotor assembly according to claim 1, characterized in that: Multiple fin holes (15) are provided on the outer periphery of the weight reduction hole (3). The multiple fin holes (15) are spaced apart along the circumferential direction of the rotor core (1) to form a fin hole structure for heat dissipation.

13. An electric motor, characterized in that: The rotor assembly includes any one of claims 1-12.

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