Motor rotor and permanent magnet synchronous motor

Abstract

The utility model discloses a motor rotor and a permanent magnet synchronous motor. The motor rotor comprises a rotor iron core; the at least two stages of permanent magnets are arranged along the axial direction, and each stage of permanent magnet comprises a plurality of permanent magnets arranged on the circumferential outer side of the rotor core; the middle accommodating groove is positioned between two adjacent stages of permanent magnets in the at least two stages of permanent magnets; the injection molding body is filled in the rotor iron core and extends into the middle accommodating groove so as to fix the rotor iron core and the at least two stages of permanent magnets together; wherein a protection structure is arranged between two adjacent stages of permanent magnets, and the protection structure is configured as a film on the surface of the permanent magnet.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor rotor and permanent magnet synchronous motor more particularly, relate to a kind of motor rotor of higher strength and the permanent magnet synchronous motor comprising the motor rotor of this. BACKGROUND

[0002] The permanent magnet of motor rotor is fixed to the core, and thus rotates under the action of magnetic field to output torque and rotation speed outward. However, for high-power permanent magnet synchronous motor, the unreliable fixation between the permanent magnet and the core can easily lead to the fragmentation or detachment of the permanent magnet during the operation of the motor, causing safety hazards. In addition, during the installation of the permanent magnet, the adjacent permanent magnets can collide and be damaged, and during the operation of the motor, wear can occur between the adjacent permanent magnets, reducing the service life of the permanent magnet. Furthermore, in order to avoid the fragmentation of the permanent magnets caused by their mutual collision during assembly, special care is usually required, which increases the assembly complexity and requires rework when the permanent magnets are fragmented, resulting in increased costs. SUMMARY

[0003] Therefore, it is desirable to provide a motor rotor and a permanent magnet synchronous motor comprising the same, which improve the deficiencies of the prior art.

[0004] The above technical problem is first solved by the motor rotor according to the utility model, which comprises: a rotor core; at least two stages of permanent magnets arranged in an axial direction, each stage of permanent magnets comprising a plurality of permanent magnets arranged on the circumferential outer side of the rotor core; an intermediate accommodating groove located between adjacent two stages of permanent magnets; and an injection body filled in the rotor core and extending into the intermediate accommodating groove to fix the rotor core and the at least two stages of permanent magnets together; wherein a protective structure is provided between the adjacent two stages of permanent magnets, and the protective structure is configured as a film on the surface of the permanent magnet.

[0005] According to the scheme, the film on the surface of the permanent magnet not only effectively prevents the fragmentation risk caused by direct collision when assembling the second stage of permanent magnets after the assembly of the first stage of permanent magnets is completed, but also optimizes the high-frequency vibration and friction problem between the two stages of magnets in the high-speed rotating state of the rotor after injection molding, thereby effectively avoiding the fragmentation of the magnets. In addition, this makes the assembly process of the permanent magnet more smooth, reducing the assembly difficulties or rework caused by collision. This not only improves the assembly efficiency, but also reduces the production cost.

[0006] In some schemes, the intermediate accommodating groove comprises a recess and a flow channel, the recess is located on the radial outer side of the intermediate accommodating groove, and the recess protrudes from the flow channel toward the two stages of permanent magnets adjacent thereto in the axial direction, respectively.

[0007] According to the scheme, the groove increases the injection space, and further strengthens the fixing strength between the permanent magnet and the iron core.

[0008] In some schemes, one end of the permanent magnet has, from the radial inner side to the radial outer side, in order, an end face, a recess, and a protrusion, the recess is recessed relative to the end face towards the axial inner side of the permanent magnet, and the protrusion protrudes relative to the end face towards the axial outer side of the permanent magnet; the groove is located between the recesses of the two adjacent permanent magnets, and the film is configured on the protrusions of the two adjacent permanent magnets.

[0009] According to the scheme, after the injection is completed, the protection structure, i.e. the film, can reduce the high-frequency friction of the two adjacent permanent magnets when the motor rotor rotates at high speed, thereby prolonging the service life of the permanent magnet.

[0010] In some schemes, the film is configured on the axial end face of the protrusion of the two adjacent permanent magnets.

[0011] In some schemes, the film is arranged on the entire surface of the permanent magnet.

[0012] In some schemes, the film is applied on the surface of the permanent magnet by high-pressure airless spraying or air spraying.

[0013] In some schemes, the film is composed of water-based paint or oil-based paint.

[0014] In some schemes, the film is composed of epoxy paint or acrylic paint.

[0015] In some schemes, the film is composed of epoxy resin glue, acrylic glue, or anaerobic glue.

[0016] In some schemes, the thickness of the film is 30-80 microns.

[0017] If the film is too thick, bubbles will be generated, reducing the bonding strength and affecting the heat dissipation of the permanent magnet. The thickness of the film should not be less than 30 microns, and if the thickness is too low, it will not play a role in preventing high-frequency impact.

[0018] In some schemes, the ratio of the depth of the groove to the length of the permanent magnet is between 0.025 and 0.04.

[0019] According to the scheme, if the groove is too shallow, the injection material may not form sufficient thickness, thereby affecting the connection strength; and if the groove is too deep, it may increase the manufacturing cost and complexity. Therefore, a suitable groove depth helps to improve the performance of the motor rotor.

[0020] In some schemes, the width of the groove in the radial direction is greater than its depth in the axial direction.

[0021] In some schemes, the injection body is formed of BMC material.

[0022] In some aspects, the motor rotor is provided with a material passage for forming the injection-molded body, the material passage including an axial material passage and a radial material passage, the radial material passage being connected to the flow channel.

[0023] In some aspects, the axial material passage includes a connection hole axially penetrating the rotor core, the connection hole being a non-circular hole, and a portion of the injection-molded body in the connection hole has a hollow portion.

[0024] According to this aspect, the hollow portion can reduce the weight of the rotor core and facilitate heat dissipation of the motor.

[0025] In some aspects, the axial material passage further includes a flow guide hole axially penetrating the rotor core, the flow guide hole being located radially outward of the connection hole, and the injection-molded body fills the flow guide hole.

[0026] In some aspects, the axial material passage further includes a flow guide groove provided in an axial direction on an outer periphery of the rotor core and abutting at least part of the permanent magnet.

[0027] According to a second aspect of the present application, a permanent magnet synchronous motor is provided, including the motor rotor according to the first aspect of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0028] Exemplary embodiments of the present application are explained in more detail below with reference to the accompanying drawings.

[0029] Figure 1 A schematic view of a motor rotor according to a first embodiment of the present application is shown;

[0030] Figure 2 A top view of a motor rotor according to a first embodiment of the present application is shown;

[0031] Figure 3 A front cross-sectional view of a motor rotor according to a first embodiment of the present application is shown;

[0032] Figure 4 is Figure 3 a partial enlarged schematic view;

[0033] Figure 5 A schematic view of a permanent magnet according to a first embodiment of the present application is shown;

[0034] Figure 6 A side view of a permanent magnet according to a first embodiment of the present application is shown;

[0035] Figure 7 A schematic view of a motor rotor according to a second embodiment of the present application is shown;

[0036] Figure 8 isFigure 7 a partial enlarged view of the schematic view of Fig. 1 ;

[0037] Figure 9 a schematic view of a permanent magnet according to a second embodiment of the present application is shown;

[0038] Figure 10 a side view of a permanent magnet according to a second embodiment of the present application is shown;

[0039] Figure 11 a partial cross-sectional view according to the present application is shown.

[0040] Reference Signs

[0041] 100 motor rotor

[0042] 110 rotor core

[0043] 120 permanent magnet

[0044] 121 end face

[0045] 122 recess

[0046] 123 protrusion

[0047] 130 intermediate receiving groove

[0048] 132 flow channel

[0049] 134 recess

[0050] 135 chamfer

[0051] 140 injection-molded body

[0052] 152 axial material passage

[0053] 154 radial material passage

[0054] 162 connecting bore

[0055] 164 flow guide bore

[0056] 166 flow guide groove

[0057] 200 motor rotor

[0058] 220 permanent magnet

[0059] 221 end face

[0060] 222 recess

[0061] 223 protrusion

[0062] 224 outer chamfer

[0063] 225 outer space

[0064] 226 chamfered corners

[0065] 227 space

[0066] 270 protective structure (film)

[0067] W1 width of recess

[0068] W2 width of protrusion

[0069] W3 width of permanent magnet

[0070] D1 depth of recess

[0071] D2 length of permanent magnet

[0072] H distance between protrusion and end face DETAILED DESCRIPTION

[0073] In order to make the purpose, scheme and advantages of the technical scheme of the utility model clearer, the technical scheme of the utility model embodiment will be described clearly and completely in the following with reference to the drawings of the specific embodiment of the utility model. Unless otherwise specified, the terms used herein have the usual meanings in the art. The same reference numerals in the drawings represent the same components.

[0074] For a clearer description, unless otherwise specified, the orientation terms appearing in this text have the following meanings: the axial direction refers to the direction parallel to the axis of the motor rotor, and the radial direction refers to the direction passing through the axis of the motor rotor and perpendicular to the axis of the motor rotor.

[0075] Figures 1 to 3 An external schematic view, a top view and an elevation sectional view of a motor rotor 100 according to a first embodiment of the utility model are shown, the motor rotor 100 mainly comprises a rotor core 110, a plurality of stages of permanent magnets 120 arranged in the axial direction (the up-down direction shown), an intermediate accommodating groove 130, an injection molded body 140 and an output shaft (not shown). Each stage of permanent magnets in the plurality of stages of permanent magnets 120 comprises a plurality of permanent magnets arranged on the circumferential outer side of the rotor core 110, and the rotation of the permanent magnets 120 can drive the output shaft to rotate, thereby outputting the rotation speed and torque to the outside. Figure 3

[0076] ​During the manufacturing of the motor rotor 100, liquid injection molding material (e.g., BMC material) is injected into the gap between the rotor core 110 and the permanent magnet 120, particularly into the intermediate receiving groove 130 between two adjacent permanent magnets 120. After cooling, the injection molding material solidifies to form an injection molded body 140. The injection molded body 140 forms a high-strength connection between the rotor core 110 and the permanent magnet 120, which not only enhances the connection strength between adjacent permanent magnets 120, but also achieves a seamless and tight connection between the rotor core 110 and the permanent magnet 120, thereby improving the overall structural integrity and performance stability of the motor rotor 100.

[0077] like Figure 4 As shown, the intermediate receiving groove 130 includes a radial direction ( Figure 4 The flow channel 132 extends in the left-right direction (as shown) and is located radially outside the intermediate receiving groove 130 (as shown). Figure 4 The groove 134 (shown on the right) protrudes axially from the flow channel 132 toward the two adjacent permanent magnets 120. The groove 134 increases the injection molding space and increases the contact area between the injection molded body 140 and the permanent magnets 120, thereby further enhancing the connection strength between the two adjacent permanent magnets 120.

[0078] In addition, a chamfer 135 is provided on the radially outer side of the groove 134. The chamfer 135 facilitates the more complete injection of the liquid injection molding material that will eventually form the injection molded body 140 into the intermediate receiving groove 130, further enhancing the fixing strength between the permanent magnet 120 and the rotor core 110, thereby effectively preventing the motor rotor 100 from breaking during high-speed rotation.

[0079] like Figure 5 and Figure 6 As shown, one end of the permanent magnet 120 (the end closest to the adjacent permanent magnet of another stage) extends from the radially inner side to the radially outer side ( Figure 6 The portion shown (from bottom to top) includes an end face 121, a recess 122, and a protrusion 123. The end face 121 is a surface perpendicular to the axial direction, and the recess 122 is axially inward of the permanent magnet 120 relative to the end face 121. Figure 6 The left side shown is recessed, and the protrusion 123 is axially outward relative to the end face 121 toward the permanent magnet 120. Figure 6 The right side (as shown) protrudes. (As shown) Figure 4As shown, the flow channel 132 of the intermediate accommodating groove 130 is located between the end faces 121 of the two adjacent stages of permanent magnets 120, the groove 134 of the intermediate accommodating groove 130 is formed by the recessed part 122 of the permanent magnet 120, and the protruding parts 123 of the two adjacent stages of permanent magnets 120 are in contact with each other. The contact between the protruding parts 123 of the two adjacent stages of permanent magnets 120 makes the pre-fixing of the motor rotor 100 before injection molding easier, and further enhances the fixing strength between the permanent magnets 120 and the rotor core 110.

[0080] Preferably, the ratio of the width W2 of the protruding part 123 of the permanent magnet 120 in the radial direction to the width W3 of the permanent magnet 120 in the radial direction can be greater than 0.2, such as 0.25 or 0.3, etc. By setting the relatively wide protruding part 123, the contact area between the adjacent permanent magnets 120 can be increased, thereby enhancing the strength of the motor rotor 100. In addition, by setting the wide protruding part 123, the pre-fixing between the two adjacent stages of permanent magnets 120 is enhanced, so it is no longer necessary to set a fixing ring in the intermediate accommodating groove 130, thereby reducing the manufacturing cost and complexity of the motor rotor 100.

[0081] It should be understood that although two stages of permanent magnets are described above, the utility model is not limited thereto, and the motor rotor can also have three, four or more stages of permanent magnets, and the adjacent two stages of permanent magnets are fixedly connected through the injection body of the intermediate accommodating groove injected between the two adjacent stages of permanent magnets.

[0082] Preferably, the ratio of the depth D1 of the groove 134 of the intermediate accommodating groove 130 in the axial direction to the length D2 of the permanent magnet 120 can be between 0.025 and 0.04, wherein the depth D1 of the groove 134 refers to the distance that the groove 134 is recessed from the flow channel 132 towards the axial inner side of the permanent magnet 120, and the length D2 of the permanent magnet 120 refers to the distance between the two end faces of the permanent magnet 120 in the axial direction. For example, the depth D1 of the groove 134 can be 2mm, and the length D2 of the permanent magnet 120 can be 61mm. The depth D1 of the groove 134 directly determines the thickness of the injection body 140 formed after the injection material fills the intermediate accommodating groove 130, and further affects the connection strength between the two adjacent stages of permanent magnets 120. If the groove 134 is too shallow, the injection material can not form sufficient thickness, thereby affecting the connection strength; and if the groove 134 is too deep, the manufacturing cost and complexity of the motor rotor 100 can be increased.

[0083] Preferably, the width W1 of the groove 134 in the radial direction can be greater than the depth D1 of the groove 134 in the axial direction. In this way, the chamfer 135 can be arranged radially outward of the groove 134. Specifically, the ratio between the width W1 of the groove 134 in the radial direction and the depth D1 of the groove 134 in the axial direction can be between 1.5 and 2.5. For example, the width W1 of the groove 134 can be 4 mm, and the depth D1 of the groove 134 can be 2 mm.

[0084] Preferably, the chamfer 135 of the groove 134 can be a rounded chamfer. Alternatively, the radius of the chamfer 135 can be equal to the depth D1 of the groove 134. In addition, the ratio between the distance H between the protrusion 123 of the permanent magnet 120 and the end face 121 in the axial direction and the depth D1 of the groove 134 can be between 1 and 2. For example, the distance between the protrusion 123 and the end face 121 can be 3 mm, and the depth D1 of the groove 134 can be 2 mm. The distance between the protrusion 123 and the end face 121 determines the width of the flow channel 132 of the intermediate accommodating groove 130. If the flow channel 132 is too narrow, it is not conducive to the injection of the injection material; if the flow channel 132 is too wide, it can increase the manufacturing cost and complexity of the motor rotor 100.

[0085] Preferably, the motor rotor 100 can be provided with a material passage for forming the injection body 140, and the material passage includes an axial material passage 152 and a radial material passage 154. The axial material passage 152 extends in the axial direction, and the radial material passage 154 extends in the radial direction and is connected with the flow channel 132 of the intermediate accommodating groove 130.

[0086] In addition, the axial material passage 152 can include a connecting hole 162 axially penetrating the rotor core 110, the connecting hole 162 is a non-circular hole, and the part of the injection body 140 in the connecting hole 162 has a hollow portion. The hollow portion can reduce the weight of the rotor core 110 and facilitate heat dissipation of the motor. Alternatively, the axial material passage 152 can further include a flow guide hole 164 axially penetrating the rotor core 110, the flow guide hole 164 is located radially outward of the connecting hole 162, and the injection body 140 fills the flow guide hole 164. In addition, the axial material passage 152 can further include a flow guide groove 166 arranged in the axial direction on the outer periphery of the rotor core 110 and abutting at least part of the permanent magnet 120. The injection material in liquid state is injected into the motor rotor 100 from the connecting hole 162, the flow guide hole 164 and the flow guide groove 166 respectively, and fills the gap between the rotor core 110 and the permanent magnet 120 along the axial material passage 152 and the radial material passage 154, and then the injection material in liquid state cools and solidifies to form the injection body 140, thereby fixing the multi-stage permanent magnet 120 and the rotor core 110 together.

[0087] Figure 7A schematic diagram of the motor rotor 200 according to the second embodiment of the present application is shown, for the sake of description brevity, the different parts between the second embodiment and the first embodiment will be mainly described, and the similar parts between the second embodiment and the first embodiment will not be described in detail. As shown in Figures 8 to 10 Unlike the relatively flat outer end surface of the permanent magnet 120 of the motor rotor 100, the radially outer side of the permanent magnet 220 of the motor rotor 200 is provided with an outer chamfer 224, the outer chamfer 224 is recessed towards the radially inner side at the axial end of the permanent magnet 220, and the outer chamfers 224 of the two adjacent stages of permanent magnets 220 form an outer space 225 accommodating the injection body 140 between them. The radially outer side of the permanent magnet 220 is also provided with two side chamfers 226, the two side chamfers 226 are located on the circumferential two sides of the outer chamfer 224, and the two side chamfers 226 of the two adjacent stages of permanent magnets 220 form two side spaces 227 accommodating the injection body 140 between them, and the outer space 225 is communicated with the groove 134 of the middle accommodating groove 130 through the two side spaces 227.

[0088] During the manufacturing of the motor rotor 200, the liquid injection material (for example, BMC material) is injected into the gap between the rotor core 210 and the permanent magnet 220, especially into the middle accommodating groove 130 between the two adjacent stages of permanent magnets 220, and the liquid injection material can flow from the groove 134 of the middle accommodating groove 130 to the outer space 225 through the two side spaces 227, thereby filling the outer space 225 under the limitation of the injection mold. After the liquid injection material is cooled and solidified, the injection material filling the outer space 225 forms an annular injection body, which coats the permanent magnet 220 from the outer side of the middle part of the motor rotor 200, thereby effectively preventing the middle part of the two stages of permanent magnets 220 from being broken at high speed. In addition, the above-mentioned integrated structure also reduces the pressure applied by the injection material to the protruding part 223 of the permanent magnet 220 during plastic packaging, which can further effectively prevent damage under the action of centrifugal force when the motor rotor 200 rotates at high speed.

[0089] Preferably, as Figure 11As shown, the protection structure 270 is configured as a film on the surface of the permanent magnet 220, and in particular, the protection structure 270 is arranged on the protruding portion 223, in particular, the axial end surface of the protruding portion 223, of the adjacent two-stage permanent magnet 220. Of course, the protection structure 270 can also be arranged on the entire surface of the permanent magnet 220. The arrangement of the protection structure 270 effectively avoids the problem of direct contact and collision between the adjacent two-stage permanent magnets 220 during placement of injection molding, and the like. In addition, after the injection molding is completed, the protection structure 270 can reduce the high-frequency vibration and friction of the adjacent two-stage permanent magnets 220 during high-speed rotation of the motor rotor 100, further ensuring the integrity of the permanent magnet, preventing fragmentation, and thereby prolonging the service life of the permanent magnet 220. In addition, this makes the assembly of the permanent magnet more smooth, and reduces the assembly difficulty or rework caused by collision. This not only improves the assembly efficiency, but also reduces the production cost.

[0090] The protection structure 270 can be applied to the surface of the permanent magnet 220 by high-pressure airless spraying or air spraying. The protection structure 270 can be composed of water-based paint or oil-based paint. In addition, the protection structure 270 can also be composed of epoxy paint or acrylic paint. In addition, the protection structure 270 can also be composed of epoxy resin glue, acrylic glue or anaerobic glue. The thickness of the protection structure 270 can be 30-80 μm. If the protection structure 270, or the film, or the paint / glue, is too thick, it will produce bubbles and reduce the bonding strength, and in addition, it will also affect the heat dissipation of the permanent magnet. The thickness of the protection structure 270 is not less than 30 μm, and if the thickness is too low, it will not prevent high-frequency impact.

[0091] The various exemplary embodiments of the utility model are described in detail with reference to the preferred embodiments, however, those skilled in the art can understand that various modifications and improvements can be made to the above specific embodiments without departing from the concept of the utility model, and various technical features and structures proposed by the utility model can also be combined without exceeding the protection scope of the utility model, and the protection scope of the utility model is determined by the appended claims.

Claims

1. A motor rotor, characterized in that, include: Rotor core; At least two stages of permanent magnets are arranged along the axial direction, each stage of permanent magnets including a plurality of permanent magnets arranged on the circumferential outer side of the rotor core; An intermediate receiving slot is located between two adjacent permanent magnets in the at least two stages of permanent magnets; An injection molded body is filled into the rotor core and extends into the intermediate receiving groove to fix the rotor core and the at least two stages of permanent magnets together. Among them, a protective structure is provided between two adjacent permanent magnets, and the protective structure is constructed as a film on the surface of the permanent magnet.

2. The motor rotor according to claim 1, characterized in that, The intermediate receiving groove includes a groove and a flow channel. The groove is located on the radially outer side of the intermediate receiving groove and protrudes axially from the flow channel toward the two adjacent permanent magnets.

3. The motor rotor according to claim 2, characterized in that, One end of the permanent magnet has an end face, a recess, and a protrusion in sequence from the radially inner side to the radially outer side. The recess is recessed relative to the end face toward the axially inner side of the permanent magnet, and the protrusion protrudes relative to the end face toward the axially outer side of the permanent magnet. The groove is located between the recesses of the two adjacent permanent magnets, and the membrane is constructed on the protrusions of the two adjacent permanent magnets.

4. The motor rotor according to claim 3, characterized in that, The membrane structure is located on the axial end face of the protrusion of the two adjacent permanent magnets.

5. The motor rotor according to claim 1, characterized in that, The film is disposed on the entire surface of the permanent magnet.

6. The motor rotor according to claim 1, characterized in that, The film is applied to the surface of the permanent magnet by high-pressure airless spraying or air spraying.

7. The motor rotor according to claim 1, characterized in that, The film is made of water-based paint or oil-based paint.

8. The motor rotor according to claim 1, characterized in that, The membrane is made of epoxy paint or acrylic paint.

9. The motor rotor according to claim 1, characterized in that, The membrane is made of an epoxy resin coating, an acrylic adhesive, or an anaerobic adhesive.

10. The motor rotor according to claim 1, characterized in that, The thickness of the membrane is 30 μm to 80 μm.

11. The motor rotor according to claim 2, characterized in that, The ratio of the depth of the groove to the length of the permanent magnet is between 0.025 and 0.

04.

12. The motor rotor according to claim 2, characterized in that, The width of the groove in the radial direction is greater than its depth in the axial direction.

13. The motor rotor according to claim 1, characterized in that, The injection molded body is formed from BMC material.

14. The motor rotor according to claim 2, characterized in that, The motor rotor is provided with a material channel for forming the injection molded body. The material channel includes an axial material channel and a radial material channel, and the radial material channel is connected to the flow channel.

15. The motor rotor according to claim 14, characterized in that, The axial material channel includes a connecting hole that axially penetrates the rotor core. The connecting hole is a non-circular hole, and the portion of the injection molded body in the connecting hole has a hollow portion.

16. The motor rotor according to claim 15, characterized in that, The axial material channel also includes a guide hole that axially penetrates the rotor core, the guide hole being located radially outside the connecting hole, and the injection molded body filling the guide hole.

17. The motor rotor according to claim 14, characterized in that, The axial material channel also includes a guide groove disposed along the axial direction on the outer periphery of the rotor core and adjacent to at least a portion of the permanent magnet.

18. A permanent magnet synchronous motor, characterized in that, Includes an electric motor rotor according to any one of claims 1 to 17.

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