Neodymium iron boron magnet and motor rotor

Abstract

The utility model relates to a neodymium iron boron magnet and a motor rotor. The neodymium-iron-boron magnet comprises a neodymium-iron-boron substrate; the neodymium iron boron base body is coated with the anti-corrosion layer, the surface of the anti-corrosion layer comprises a first surface and a second surface, and the first surface and the second surface are perpendicular to the orientation direction of the neodymium iron boron base body; the epoxy resin layer is coated on the first surface and the second surface of the anti-corrosion layer, and the other surfaces of the anti-corrosion layer are not covered by the epoxy resin layer. The epoxy resin layer is arranged on part of the surface of the anti-corrosion layer, and no epoxy resin layer is arranged on the other surface of the anti-corrosion layer, so that the dosage of epoxy resin in the neodymium-iron-boron magnet is reduced, and the manufacturing cost of the neodymium-iron-boron magnet is reduced.

Description

Technical Field

[0001] This application relates to the field of magnet manufacturing, and more particularly to a neodymium iron boron magnet and a motor rotor. Background Technology

[0002] Sintered NdFeB magnets are widely used due to their excellent magnetic properties. However, NdFeB magnets have poor chemical stability and are prone to oxidation under normal operating conditions. They are also susceptible to electrochemical oxidation corrosion under humid and hot conditions, thus requiring surface protection through coating or plating. Existing NdFeB magnets typically have an anti-corrosion layer coated on the outside of the substrate, followed by an epoxy resin layer. The epoxy resin layer offers excellent insulation properties, improving the insulation performance of the NdFeB magnet and reducing eddy current losses. However, applying epoxy resin layers to all surfaces of the NdFeB magnet results in high mass production costs. Utility Model Content

[0003] To address the aforementioned issues, this application provides a neodymium iron boron magnet and a motor rotor that can reduce the manufacturing cost of neodymium iron boron magnets.

[0004] Embodiments of this application provide a neodymium iron boron magnet, comprising:

[0005] Neodymium iron boron matrix;

[0006] An anti-corrosion layer is provided to cover the NdFeB substrate. The surface of the anti-corrosion layer includes a first surface and a second surface, both of which are perpendicular to the orientation direction of the NdFeB substrate.

[0007] An epoxy resin layer is coated on the first and second surfaces of the anti-corrosion layer, and the remaining surfaces of the anti-corrosion layer are not covered by the epoxy resin layer.

[0008] According to some embodiments of this application, the ratio of the area of ​​the first surface covered by the epoxy resin layer to the area of ​​the first surface is 50%-100%.

[0009] According to some embodiments of this application, the ratio of the area of ​​the second surface covered by the epoxy resin layer to the area of ​​the second surface is 50%-100%.

[0010] According to some embodiments of this application, the surface roughness Ra of the anti-corrosion layer is 0.5-1.5 μm.

[0011] According to some embodiments of this application, the surface roughness Ra of the epoxy resin layer is 1-2.5 μm, and the thickness of the epoxy resin layer is 8-150 μm.

[0012] According to some embodiments of this application, the anti-corrosion layer includes a passivation layer or a phosphating layer, which covers the NdFeB substrate.

[0013] According to some embodiments of this application, the thickness of the anti-corrosion layer is 1-4 μm.

[0014] According to some embodiments of this application, the thickness of the NdFeB substrate is 1-50 mm.

[0015] An embodiment of this application provides a motor rotor, comprising:

[0016] The rotor body is provided with magnet slots;

[0017] The neodymium iron boron magnets described above are disposed in the magnet slots of the rotor body.

[0018] This application provides an epoxy resin layer on a portion of the anti-corrosion layer surface and does not provide an epoxy resin layer on the remaining surface of the anti-corrosion layer, thereby reducing the amount of epoxy resin used in the NdFeB magnet and thus reducing the manufacturing cost of the NdFeB magnet. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without exceeding the scope of protection claimed by this application.

[0020] Figure 1 This is a schematic diagram of a neodymium iron boron magnet according to an embodiment of this application;

[0021] Figure 2 This is a schematic diagram of the motor rotor in an embodiment of this application. Detailed Implementation

[0022] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] like Figure 1 As shown, one embodiment of this application provides a neodymium iron boron magnet 100, which includes a neodymium iron boron substrate 1, an anti-corrosion layer 2, and an epoxy resin layer 3.

[0024] The NdFeB substrate 1 is sintered from NdFeB material. The anti-corrosion layer 2 covers all surfaces of the NdFeB substrate 1. For example, if the NdFeB substrate 1 is a cuboid, the anti-corrosion layer 2 covers all six surfaces of the NdFeB substrate 1. The surfaces of the anti-corrosion layer 2 include opposing first surfaces 2a and second surfaces 2b, both of which are perpendicular to the orientation direction of the NdFeB substrate 1. Figure 1 The arrows indicate the orientation direction of the NdFeB substrate 1. The anti-corrosion layer 2 serves to prevent oxidation and corrosion, and improve the corrosion resistance of the NdFeB magnet 100.

[0025] An epoxy resin layer 3 is coated on the first surface 2a and the second surface 2b of the anti-corrosion layer 2. The epoxy resin layer 3 can improve the insulation performance of the NdFeB magnet 100 and reduce the eddy current loss of the NdFeB magnet 100. The remaining surfaces of the anti-corrosion layer 2 are exposed. For example, the anti-corrosion layer 2 is a cuboid, and the four surfaces of the anti-corrosion layer 2 parallel to the orientation direction of the NdFeB magnet 100 are not coated with the epoxy resin layer 3.

[0026] In this embodiment, an epoxy resin layer is provided on a portion of the surface of the anti-corrosion layer 2, while no epoxy resin layer is provided on the remaining surface of the anti-corrosion layer 2. This satisfies the performance requirements of the NdFeB magnet 100 while reducing the amount of epoxy resin used in the NdFeB magnet, thereby reducing the manufacturing cost of the NdFeB magnet.

[0027] In some embodiments, the ratio of the area of ​​the first surface 2a covered by the epoxy resin layer 3 to the area of ​​the first surface 2a is 50%-100%. If the area of ​​the first surface 2a covered by the epoxy resin layer 3 is too small, the eddy current loss of the neodymium iron boron magnet 100 will be large, affecting the performance of the neodymium iron boron magnet 100.

[0028] In some embodiments, the ratio of the area of ​​the second surface 2b covered by the epoxy resin layer 3 to the area of ​​the second surface 2b is 50%-100%. If the area of ​​the second surface 2b covered by the epoxy resin layer 3 is too small, the eddy current loss of the neodymium iron boron magnet 100 will be large, affecting the performance of the neodymium iron boron magnet 100.

[0029] In some embodiments, the thickness of the epoxy resin layer 3 is 8-150 μm, for example, the thickness of the epoxy resin layer 3 is 8 μm, 20 μm, 30 μm, 50 μm, 80 μm, 100 μm, 120 μm or 150 μm. An excessively thick epoxy resin layer 3 will increase the manufacturing cost of the NdFeB magnet 100, while an excessively thin epoxy resin layer 3 will result in a larger eddy current loss in the NdFeB magnet 100.

[0030] In some embodiments, the thickness of the epoxy resin layer is 8-20 μm. For example, the thickness of the epoxy resin layer 3 is 8 μm, 10 μm, 15 μm or 20 μm.

[0031] In some embodiments, the surface roughness Ra of the anti-corrosion layer 2 is 0.5-1.5 μm, which facilitates the coating of the epoxy resin layer 3 onto the surface of the anti-corrosion layer 2 and also facilitates the bonding of the neodymium iron boron magnet 100 to other components.

[0032] In some embodiments, the surface roughness Ra of the epoxy resin layer 3 is 1-2.5 μm. When the neodymium iron boron magnet 100 is used in electronic devices, it is usually connected to other components by adhesive bonding. The surface of the epoxy resin layer 3 is too smooth, which is not conducive to the bonding of the neodymium iron boron magnet 100 to the adhesive.

[0033] In some embodiments, the anti-corrosion layer 2 is a passivation layer or a phosphating layer, which covers the NdFeB substrate 1. Both the passivation layer and the phosphating layer can prevent oxidative corrosion.

[0034] In some embodiments, the thickness of the anti-corrosion layer 2 is 1-4 μm. If the thickness of the anti-corrosion layer 2 is too small, it affects the corrosion resistance of the NdFeB magnet 100. If the thickness of the anti-corrosion layer 2 is too large, it increases the cost of the NdFeB magnet 100.

[0035] In some embodiments, the thickness of the NdFeB substrate 1 is 1-50 mm.

[0036] like Figure 2 As shown, an embodiment of this application provides a motor rotor, which includes a neodymium iron boron magnet 100 and a rotor body 200 as described above. The rotor body 200 is provided with a magnet slot 210, and the neodymium iron boron magnet 100 is disposed in the magnet slot 210 of the rotor body 200. The neodymium iron boron magnet 100 is bonded to the magnet slot 210 by adhesive 300.

[0037] Optionally, the adhesive 300 is bonded to the epoxy resin layer 3 of the neodymium iron boron magnet 100. If necessary, the adhesive 300 can also be filled around the neodymium iron boron magnet 100 so that the adhesive 300 fills the gap between the neodymium iron boron magnet 100 and the groove wall of the magnet groove 210.

[0038] In some embodiments, the epoxy resin layer 3 contains an expanding agent, and the components of the epoxy resin layer 3 include epoxy resin, expanding agent, curing agent, and thermoplastic resin. The mass ratio of each component in the epoxy resin layer 3 is: epoxy resin 60-80, thermoplastic resin 15-25, expanding agent 6-10, and curing agent 0.6-1.5.

[0039] The thermoplastic resin is at least one of acrylic resin, polysulfone resin, and melamine-formaldehyde resin, and the curing agent is at least one of phenolic resin curing agent and aliphatic polyamine curing agent. The aliphatic polyamine curing agent is at least one of ethylenediamine, diethylenetriamine, and triethylenetetramine.

[0040] The expanding agent can be a physical foaming agent or a chemical foaming agent. Optionally, the physical foaming agent is expandable hollow microspheres. The expandable hollow microspheres can consist of a shell made of thermoplastic material and a low-boiling-point hydrocarbon encapsulated in the shell. Optionally, the chemical expanding agent is one of expandable graphite, ammonium polyphosphate, azodicarbonamide, and N-aminoethylpiperazine (ATP) adsorbed on nano-silica.

[0041] The epoxy resin layer 3 containing the expanding agent has a thickness of 40-150 μm, a softening point of 60-80℃, and an expansion rate of 80-500%. The epoxy resin layer 3 will thermocure and expand at 150-200℃ for direct bonding to the rotor body 200, without the need to coat the outside of the epoxy resin layer 3 with adhesive.

[0042] Example 1

[0043] The NdFeB substrate is N42SH, with a phosphate layer coated on the outside. An epoxy resin layer is sprayed onto both the first and second surfaces of the phosphate layer. The epoxy resin layer is composed of epoxy resin and has a thickness of 20 μm.

[0044] Example 2

[0045] The NdFeB matrix is ​​N42SH, with a phosphate layer coated on the outside. An epoxy resin layer containing an expanding agent is sprayed onto the first and second surfaces of the phosphate layer. The epoxy resin layer comprises 80 parts by weight of epoxy resin, 20 parts by weight of waterborne acrylic resin, 8 parts by weight of expanding balls, and 1 part by weight of phenolic resin curing agent. The thickness of the epoxy resin layer is 120 μm.

[0046] Comparative Example 1

[0047] The NdFeB substrate is N42SH. A phosphate layer is coated on the outside of the NdFeB substrate, and an epoxy resin layer is sprayed on the outside of the phosphate layer, covering the entire surface of the phosphate layer. The epoxy resin layer consists of epoxy resin and has a thickness of 20 μm. The NdFeB substrate and phosphate layer used in Examples 1, 2, and Comparative Example 1 are all the same.

[0048] Table 1

[0049]

[0050] The comparison shows that the corrosion resistance of the NdFeB magnets in Examples 1 and 2 is close to that of the NdFeB magnet in Reference Document 1. The insulation performance of the NdFeB magnets in Examples 1 and 2 is also close to that of the NdFeB magnet in Reference Document 1, both of which meet the requirement of not conducting at 1000V.

[0051] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the technical solutions and core ideas of this application. Therefore, any changes or modifications made by those skilled in the art based on the ideas of this application, and on the specific implementation methods and application scope of this application, are all within the scope of protection of this application. In summary, the content of this specification should not be construed as a limitation of this application.

Claims

1. A neodymium iron boron magnet, characterized in that, include: Neodymium iron boron matrix; An anti-corrosion layer is provided to cover the NdFeB substrate. The surface of the anti-corrosion layer includes a first surface and a second surface, both of which are perpendicular to the orientation direction of the NdFeB substrate. An epoxy resin layer is coated on the first and second surfaces of the anti-corrosion layer, and the remaining surfaces of the anti-corrosion layer are not covered by the epoxy resin layer.

2. The neodymium iron boron magnet according to claim 1, characterized in that, The ratio of the area of ​​the first surface covered by the epoxy resin layer to the area of ​​the first surface is 50%-100%.

3. The neodymium iron boron magnet according to claim 1, characterized in that, The ratio of the area of ​​the second surface covered by the epoxy resin layer to the area of ​​the second surface is 50%-100%.

4. The neodymium iron boron magnet according to claim 1, characterized in that, The surface roughness Ra of the anti-corrosion layer is 0.5-1.5 μm.

5. The neodymium iron boron magnet according to claim 1, characterized in that, The surface roughness Ra of the epoxy resin layer is 1-2.5 μm, and the thickness of the epoxy resin layer is 8-150 μm.

6. The neodymium iron boron magnet according to claim 1, characterized in that, The anti-corrosion layer includes a passivation layer or a phosphating layer, which covers the NdFeB substrate.

7. The neodymium iron boron magnet according to claim 1, characterized in that, The thickness of the anti-corrosion layer is 1-4 μm.

8. The neodymium iron boron magnet according to claim 1, characterized in that, The thickness of the neodymium iron boron substrate is 1-50 mm.

9. A motor rotor, characterized in that, include: The rotor body is provided with magnet slots; The neodymium iron boron magnet as described in any one of claims 1 to 8 is disposed in the magnet slot of the rotor body.

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