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 an outer side space filled with an injection molding body is formed between every two adjacent stages of permanent magnets, and the injection molding body in each outer side space wraps the end part between every two adjacent stages of permanent magnets.

Description

Technical Field

[0001] This utility model relates to motor rotors and permanent magnet synchronous motors, and more specifically, to a motor rotor with higher strength and a permanent magnet synchronous motor including the motor rotor. Background Technology

[0002] The permanent magnets of a motor rotor are fixed to the iron core, causing it to rotate under the influence of the magnetic field and output torque and speed. However, for high-power permanent magnet synchronous motors, the fixing between the permanent magnets and the iron core may be unreliable, which can easily lead to the permanent magnets breaking or detaching during motor operation, causing safety hazards.

[0003] Therefore, it is hoped that a motor rotor can be proposed to overcome the shortcomings of the existing technology. Utility Model Content

[0004] According to a first aspect of the present invention, an electric motor rotor is provided, comprising: a rotor core; at least two stages of permanent magnets arranged in an 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 groove located between two adjacent stages of permanent magnets; and an injection-molded body filled within the rotor core and extending into the intermediate receiving groove to fix the rotor core and the at least two stages of permanent magnets together; wherein an outer space filled with the injection-molded body is formed between two adjacent stages of permanent magnets, and the injection-molded body in the outer space covers the middle end of the two adjacent stages of permanent magnets.

[0005] According to the scheme, the injection molding material filling the outer space forms a ring-shaped injection body. The ring-shaped injection body covers the permanent magnet from the outside of the middle of the motor rotor, thereby effectively preventing the middle part of the two-stage permanent magnet from breaking at high speed.

[0006] In some designs, the outer radial side of the permanent magnet may be provided with an outer chamfer, which is recessed radially inward at the axial end of the permanent magnet, and an outer space is formed between the outer chamfers of two adjacent permanent magnets.

[0007] In some designs, two adjacent permanent magnets can form two side spaces to accommodate the injection molded body. These two side spaces are located on the circumferential sides of the outer space, and the outer space is connected to the middle receiving groove through the two side spaces.

[0008] In some designs, the radial outer side of the permanent magnet may also have two chamfers, which are located on both sides of the outer chamfer in the circumferential direction, and a space is formed between the two chamfers of two adjacent permanent magnets.

[0009] According to the scheme, liquid injection material can flow from the middle receiving tank to the outer space through the two side spaces, thereby filling the outer space under the constraint of the injection mold, and then forming an injection molded body covering the permanent magnet in the outer space.

[0010] In some designs, the intermediate receiving groove may include a groove and a flow channel. The groove is located radially outside the intermediate receiving groove and protrudes axially from the flow channel toward the two adjacent permanent magnets. The outer space is connected to the groove through the two side spaces.

[0011] According to the design, the groove increases the injection molding space, further strengthening the fixation strength between the permanent magnet and the iron core.

[0012] In some designs, one end of the permanent magnet may have 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 formed by the recess, and the protrusions of adjacent permanent magnets are in contact with each other.

[0013] According to the scheme, the protrusions of adjacent permanent magnets contact each other, making it easier to pre-fix the motor rotor before injection molding, and further enhancing the fixing strength between the permanent magnet and the rotor core.

[0014] In some designs, the ratio of the depth of the groove along the axial direction to the length of the permanent magnet can be between 0.025 and 0.04.

[0015] According to this scheme, if the groove is too shallow, the injection-molded material may not be able to form sufficient thickness, thus affecting the connection strength; while if the groove is too deep, it may increase manufacturing costs and complexity. Therefore, an appropriate groove depth helps to improve the performance of the motor rotor.

[0016] In some designs, the width of the groove in the radial direction can be greater than its depth in the axial direction.

[0017] In some designs, the ratio between the radial width of the groove and its axial depth can be between 1.5 and 2.5.

[0018] In some designs, the ratio of the axial distance between the protrusion and the end face to the depth of the groove can be between 1 and 2.

[0019] In some designs, the injection molded body can be formed from BMC material.

[0020] In some designs, the motor rotor may be provided with material channels for forming the injection molded body. The material channels include axial material channels and radial material channels, with the radial material channels connected to the flow channels.

[0021] In some embodiments, the axial material channel may include 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.

[0022] According to this design, the hollow section can reduce the weight of the rotor core and is beneficial for the heat dissipation of the motor.

[0023] In some designs, the axial material channel may also include 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.

[0024] In some embodiments, the axial material channel may also include 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.

[0025] According to a second aspect of the present invention, a permanent magnet synchronous motor is provided, comprising the motor rotor described in the first aspect of the present invention. Attached Figure Description

[0026] Figure 1 A schematic diagram of a motor rotor according to a first embodiment of the present invention is shown;

[0027] Figure 2 A top view of a motor rotor according to a first embodiment of the present invention is shown;

[0028] Figure 3 A front cross-sectional view of a motor rotor according to a first embodiment of the present invention is shown;

[0029] Figure 4 yes Figure 3 A magnified view of a portion of the image;

[0030] Figure 5 A schematic diagram of a permanent magnet according to a first embodiment of the present invention is shown;

[0031] Figure 6 A side view of a permanent magnet according to a first embodiment of the present invention is shown;

[0032] Figure 7 A schematic diagram of a motor rotor according to a second embodiment of the present invention is shown;

[0033] Figure 8 yes Figure 7 A magnified view of a portion of the image;

[0034] Figure 9 A schematic diagram of a permanent magnet according to a second embodiment of the present invention is shown;

[0035] Figure 10 A side view of a permanent magnet according to a second embodiment of the present invention is shown;

[0036] Figure 11 A partial cross-sectional view according to a second embodiment of the present invention is shown.

[0037] Figure Labels

[0038] 100 motor rotor

[0039] 110 Rotor Core

[0040] 120 permanent magnet

[0041] 121 end face

[0042] 122 recess

[0043] 123 Protrusion

[0044] 130 Intermediate Reception Tank

[0045] 132 flow channels

[0046] 134 Grooves

[0047] 135° chamfer

[0048] 140 injection molded body

[0049] 152 Axial Material Channel

[0050] 154 Radial Material Channels

[0051] 162 connecting hole

[0052] 164 guide holes

[0053] 166 Guide Channel

[0054] 200 motor rotor

[0055] 220 permanent magnet

[0056] 221 end face

[0057] 222 recess

[0058] 223 Prominent part

[0059] 224 Outer chamfer

[0060] 225 Outer Space

[0061] 226 Chamfering on both sides

[0062] 227 Side Space

[0063] 270 Buffer Structure (Annular Gasket)

[0064] The width of the W1 groove

[0065] Width of W2 protrusion

[0066] The width of the W3 permanent magnet

[0067] D1 Depth of the groove

[0068] D2 Length of the permanent magnet

[0069] Thickness of D3 buffer structure

[0070] Distance between H protrusion and end face Detailed Implementation

[0071] To make the objectives, solutions, and advantages of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Unless otherwise stated, the terms used herein have their ordinary meanings in the art. The same reference numerals in the drawings represent the same parts.

[0072] For clarity, unless otherwise explicitly stated, the directional terms used in this document are defined as follows: axial direction refers to the direction parallel to the axis of the motor rotor, and radial direction refers to the direction passing through and perpendicular to the axis of the motor rotor.

[0073] Figures 1 to 3 The following diagrams show an external schematic, a top view, and a front cross-sectional view of a motor rotor 100 according to a first embodiment of the present invention. The motor rotor 100 mainly includes a rotor core 110 and a rotor along the axial direction (…). Figure 3 The multi-stage permanent magnet 120, intermediate receiving groove 130, injection molded body 140, and output shaft (not shown) are arranged in the vertical direction. Each stage of the multi-stage permanent magnet 120 includes multiple permanent magnets arranged on the circumferential outer side of the rotor core 110. The rotation of the permanent magnet 120 can drive the output shaft to rotate, thereby outputting speed and torque to the outside.

[0074] 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.

[0075] like Figure 4 As shown, the intermediate receiving groove 130 includes a radial direction ( Figure 4The 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.

[0076] 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.

[0077] 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 4 As shown, the flow channel 132 of the intermediate receiving groove 130 is located between the end faces 121 of the two adjacent permanent magnets 120. The groove 134 of the intermediate receiving groove 130 is formed by the recess 122 of the permanent magnet 120, and the protrusions 123 of the two adjacent permanent magnets 120 are in contact with each other. The contact between the protrusions 123 of the two adjacent permanent magnets 120 makes the pre-fixation 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.

[0078] Preferably, the ratio of the radial width W2 of the protrusion 123 of the permanent magnet 120 to the radial width W3 of the permanent magnet 120 can be greater than 0.2, for example, 0.25 or 0.3. By providing a relatively wide protrusion 123, the contact area between adjacent permanent magnets 120 can be increased, thereby enhancing the strength of the motor rotor 100. In addition, by providing a wider protrusion 123, the pre-fixation between adjacent two-stage permanent magnets 120 is strengthened, so there is no need to provide a fixing ring in the intermediate receiving groove 130, thereby reducing the manufacturing cost and complexity of the motor rotor 100.

[0079] It should be understood that although two-stage permanent magnets have been described above, the present invention is not limited thereto. The motor rotor may also have three, four or more stages of permanent magnets, and adjacent two-stage permanent magnets are fixedly connected by an injection-molded body injected into an intermediate receiving groove between the adjacent two-stage permanent magnets.

[0080] Preferably, the ratio of the axial depth D1 of the groove 134 in the intermediate receiving groove 130 to the length D2 of the permanent magnet 120 can be between 0.025 and 0.04, where the depth D1 of the groove 134 refers to the distance the groove 134 is recessed from the flow channel 132 toward the axial inner side of the permanent magnet 120, and the length D2 of the permanent magnet 120 refers to the axial distance between the two end faces of the permanent magnet 120. For example, the depth D1 of the groove 134 can be 2 mm, and the length D2 of the permanent magnet 120 can be 61 mm. The depth D1 of the groove 134 directly determines the thickness of the injection molded body 140 formed after the injection molding material is filled into the intermediate receiving groove 130, thus affecting the connection strength between adjacent permanent magnets 120. If the groove 134 is too shallow, the injection molding material may not be able to form sufficient thickness, thus affecting the connection strength; while if the groove 134 is too deep, it may increase the manufacturing cost and complexity of the motor rotor 100.

[0081] Preferably, the radial width W1 of the groove 134 can be greater than its axial depth D1. This facilitates the provision of a chamfer 135 on the radially outer side of the groove 134. Specifically, the ratio between the radial width W1 of the groove 134 and its axial depth D1 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 can be 2 mm.

[0082] Preferably, the chamfer 135 of the groove 134 can be a rounded corner. Optionally, the radius of the chamfer 135 can be equal to the depth D1 of the groove 134. Furthermore, the ratio of the axial distance H between the protrusion 123 of the permanent magnet 120 and the end face 121 to 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 receiving groove 130. If the flow channel 132 is too narrow, it is not conducive to the injection of molding material; while if the flow channel 132 is too wide, it may increase the manufacturing cost and complexity of the motor rotor 100.

[0083] Preferably, the motor rotor 100 may be provided with material channels for forming the injection molded body 140, the material channels including an axial material channel 152 and a radial material channel 154. The axial material channel 152 extends in the axial direction, and the radial material channel 154 extends in the radial direction and is connected to the flow channel 132 of the intermediate receiving groove 130.

[0084] Furthermore, the axial material channel 152 may include a connecting hole 162 axially penetrating the rotor core 110. The connecting hole 162 is a non-circular hole, and the portion of the injection molded body 140 within 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. Optionally, the axial material channel 152 may also include a guide hole 164 axially penetrating the rotor core 110, the guide hole 164 being located radially outside the connecting hole 162, and the injection molded body 140 filling the guide hole 164. Additionally, the axial material channel 152 may also include a guide groove 166 axially disposed on the outer periphery of the rotor core 110 and adjacent to at least a portion of the permanent magnet 120. Liquid injection molding material is injected into the motor rotor 100 through the connecting hole 162, the guide hole 164 and the guide groove 166 respectively, and fills the gap between the rotor core 110 and the permanent magnet 120 along the axial material channel 152 and the radial material channel 154. Then the liquid injection molding material cools and solidifies to form an injection molded body 140, thereby fixing the multi-stage permanent magnet 120 and the rotor core 110 together.

[0085] Figure 7 A schematic diagram of a motor rotor 200 according to a second embodiment of the present invention is shown. For the sake of brevity, the following description will focus on the differences between the second embodiment and the first embodiment; similarities between the second embodiment and the first embodiment will not be described in detail. Figures 8 to 10 As shown, unlike the relatively flat outer end face of the permanent magnet 120 of the motor rotor 100, the permanent magnet 220 of the motor rotor 200 has an outer chamfer 224 on its radially outer side. The outer chamfer 224 is recessed radially inward at the axial end of the permanent magnet 220. An outer space 225 for accommodating the injection molded body 140 is formed between the outer chamfers 224 of two adjacent permanent magnets 220. The permanent magnet 220 also has two side chamfers 226 on its radially outer side. The two side chamfers 226 are located on both circumferential sides of the outer chamfer 224. Two side spaces 227 for accommodating the injection molded body 140 are formed between the two side chamfers 226 of two adjacent permanent magnets 220. The outer space 225 is connected to the groove 134 of the intermediate receiving groove 130 through the two side spaces 227.

[0086] During the manufacturing of the motor rotor 200, liquid injection molding material (e.g., BMC material) is injected into the gap between the rotor core 210 and the permanent magnet 220, particularly into the intermediate receiving groove 130 between two adjacent permanent magnets 220. The liquid injection molding material can flow from the groove 134 of the intermediate receiving groove 130 to the outer space 225 via the two side spaces 227, thereby filling the outer space 225 under the constraint of the injection mold. After the liquid injection molding material cools and solidifies, the injection molding material filling the outer space 225 forms an annular injection body. The annular injection body covers the permanent magnet 220 from the outside of the middle part of the motor rotor 200, thereby effectively preventing the middle part of the two permanent magnets 220 from breaking at high speeds. In addition, the above-mentioned one-piece molding structure also reduces the pressure exerted by the injection molding material on the protrusions 223 of the permanent magnet 220 during molding, which can further effectively prevent damage to the motor rotor 200 under centrifugal force when rotating at high speeds.

[0087] Preferably, such as Figure 11 As shown, a buffer structure 270 is provided between two adjacent permanent magnets 220. The buffer structure 270 is made of an elastic material and is disposed between the protrusions 223 of the two adjacent permanent magnets 220. The buffer structure 270 avoids direct contact and collision between the two adjacent permanent magnets 220 during injection molding, preventing breakage. Furthermore, after injection molding, the buffer structure 270 reduces the high-frequency friction between the two adjacent permanent magnets 220 when the motor rotor 100 rotates at high speed, thereby extending the service life of the permanent magnets 220. For example, the buffer structure 270 can be an annular gasket. The radial width of the annular gasket 270 does not exceed the radial width of the protrusions 223 of the permanent magnets 220. For example, the radial width of the annular gasket 270 is not less than 2.25 mm, so that the annular gasket 270 is wide enough to provide a buffering effect. Optionally, the annular gasket 270 is formed of at least one of the following materials: rubber, silicone, or thermoplastic elastomer. Furthermore, the thickness D3 of the annular gasket 270 along the axial direction can be between 0.5 mm and 3 mm. If the thickness D3 of the annular gasket 270 is too thick (for example, more than 3 mm), it will have a negative impact on the magnetic force of the two adjacent permanent magnets 220; while if the thickness D3 of the annular gasket 270 is too thin (for example, less than 0.5 mm), it will not be able to provide sufficient buffering.

[0088] This document describes in detail several exemplary embodiments of the present invention with reference to preferred embodiments. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of the present invention, and various technical features and structures proposed in the present invention can be combined without exceeding the protection scope of the present invention, which is determined by the appended claims.

Claims

1. An electric machine rotor, characterized in that, The motor rotor 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 a circumferential outer side of the rotor core; an intermediate accommodation groove between adjacent two stages of permanent magnets among the at least two stages of permanent magnets; an injection body filled in the rotor core and extending into the intermediate accommodation groove to fix the rotor core and the at least two stages of permanent magnets together; wherein an outer side space filled with the injection body is formed between the adjacent two stages of permanent magnets, and the injection body in the outer side space covers end portions between the adjacent two stages of permanent magnets.

2. The electric machine rotor of claim 1, wherein, An outer side chamfer is arranged on a radially outer side of the permanent magnet, the outer side chamfer is recessed towards a radially inner side at an axial end portion of the permanent magnet, and an outer side space is formed between the outer side chamfers of the adjacent two stages of permanent magnets.

3. The motor rotor of claim 2, wherein, An inner side space accommodating the injection body is formed between the adjacent two stages of permanent magnets, and the inner side space is located on two circumferential sides of the outer side space, and the outer side space is communicated with the intermediate accommodation groove through the inner side space.

4. The motor rotor of claim 3, wherein An inner side chamfer is further arranged on a radially inner side of the permanent magnet, the inner side chamfer is located on two circumferential sides of the outer side chamfer, and the inner side space is formed between the inner side chamfers of the adjacent two stages of permanent magnets.

5. The electric machine rotor of claim 4, wherein, The intermediate accommodation groove comprises a groove and a flow channel, the groove is located on a radially outer side of the intermediate accommodation groove, the groove protrudes towards two adjacent stages of permanent magnets respectively along an axial direction from the flow channel, and the outer side space is communicated with the groove through the inner side space.

6. The motor rotor according to claim 5, wherein one end of the permanent magnet has, from a radially inner side to a radially outer side, in sequence, an end face, a recessed portion and a protruding portion, the recessed portion is recessed towards an axial inner side of the permanent magnet relative to the end face, and the protruding portion protrudes towards an axial outer side of the permanent magnet relative to the end face; the groove is located between the recessed portions of the adjacent two stages of permanent magnets, and the protruding portions of the adjacent two stages of permanent magnets are in contact with each other.

7. The motor rotor of claim 6, wherein A ratio of a depth of the groove to a length of the permanent magnet is between 0.025 and 0.

04.

8. The motor rotor of claim 7, wherein, A width of the groove in a radial direction is greater than a depth of the groove in an axial direction.

9. The electric machine rotor of claim 8, wherein, A ratio between the width of the groove in the radial direction and the depth of the groove in the axial direction is between 1.5 and 2.

5.

10. The motor rotor of claim 8, wherein, A ratio between a distance between the protruding portion and the end face in the axial direction and the depth of the groove is between 1 and 2.

11. The motor rotor of claim 1, wherein The injection body is formed of a BMC material.

12. The motor rotor of claim 5, wherein, The motor rotor is provided with a material channel for forming the injection body, the material channel comprises an axial material channel and a radial material channel, and the radial material channel is connected with the flow channel.

13. The electric machine rotor of claim 12, wherein, The axial material channel comprises a connecting hole axially penetrating through the rotor core, the connecting hole is a non-circular hole, and a portion of the injection body in the connecting hole has a hollow portion.

14. The electric machine rotor of claim 13, wherein, The axial material channel further comprises a flow guide hole axially penetrating through the rotor core, the flow guide hole is located on a radially outer side of the connecting hole, and the injection body fills the flow guide hole.

15. The electric machine rotor of claim 12, wherein, The axial material passage further comprises a flow guide groove arranged in the axial direction on the outer periphery of the rotor core and adjoining the at least partial permanent magnet.

16. A permanent magnet synchronous motor, characterized by, An electric machine rotor comprising any of the features of claims 1 to 15.

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