A motor rotor magnetic adhesive for improving high-temperature magnetic flux and a motor rotor

Abstract

The present invention relates to the field of motor adhesives, and particularly to a motor rotor magnetic adhesive and a motor rotor for improving high-temperature magnetic flux. The motor rotor magnetic adhesive comprises the following raw materials in parts by mass: 5-15 parts of epoxy resin, 1-3 parts of phenolic resin, 0.5-2 parts of curing accelerator, 15-30 parts of fused spherical silica, 40-60 parts of fused angular silica, 4-10 parts of fumed silica, 1-3 parts of silane coupling agent, and 5-30 parts of magnetic powder; the D50 of the fused spherical silica is 5-9 μm, the D50 of the fused angular silica is 15-21 μm, and the specific surface area of the fumed silica is 230-280 m<supgt;2< / supgt> / g. The present invention uses magnetic material powder as part of the solid filler, and in combination with silica fillers of specific sizes, improves the high-temperature magnetic flux of the overall material while maintaining good mechanical strength.

Description

Technical Field

[0001] The present invention relates to the field of motor adhesives, and in particular to a motor rotor magnetic adhesive and a motor rotor for improving high-temperature magnetic flux. Background Art

[0002] Under the guidance of global green energy, the gradual maturity of the new energy vehicle industry chain technology has provided the market with better choices. Among them, for most new energy vehicles, the fixing method of the permanent magnet motor, the magnet and the iron core is a key process. Several common methods include glue fixing, injection molding fixing, and rivet point fixing. Glue fixing was the early method used to fix the magnet in the rotor core with epoxy glue, etc. However, the fixing performance was not stable, and the strength loss over time was large. This method has basically been phased out and may only be used in small-batch proofing experiments. Injection molding fixing is a new technology developed in recent years. An injection molding material is injected around the magnet to form a fixation, providing more stable performance. The mainstream magnetic fixing materials for motor rotors on the market include Sumitomo's M500A and Yuanzong 8200TM. With the rise of new energy vehicles and the improvement of electric vehicle performance, the demand for torque provided by motors is increasing. Especially when the motor speed is higher than 17,000 rpm, thermosetting materials have become the preferred choice for magnet fixing materials. Using epoxy resin to fix the motor rotor is a common method. Thermosetting epoxy resin has good toughness, impact resistance, vibration resistance, and corrosion resistance, and has excellent bonding effects, so it has a relatively wide range of applications. However, the epoxy resin will cause magnetic flux loss in the rotor during the filling process, and its use in some scenarios is restricted. At present, there is no fixing method that can improve the rotor magnetic flux. Theoretically, adding high-permeability magnetic powder directionally in epoxy molding compound (EMC) may enhance the magnetic circuit continuity, thereby increasing the overall magnetic flux density. However, through experiments, it is found that directly adding magnetic powder has little effect on improving the magnetic flux. There are many possible reasons. For example, the interfacial bonding strength and dispersion uniformity between the magnetic powder and the epoxy resin directly affect the stability of the magnetic permeability; it may also be due to the fluidity and close packing mode of non-magnetic fillers, etc., which will all affect the magnetic flux.

[0003] CN103081301B discloses a rotor, which includes a rotor core fixedly arranged on a rotating shaft and provided with a plurality of hole parts arranged along the peripheral part of the rotating shaft; magnets inserted into the hole parts; a fixing member formed by curing a fixing resin composition filled in the separation part between the hole parts and the magnets, and arranged on at least the side wall located on the inner circumferential side of the rotor core among the side walls of the magnets to fix the magnets; the fixing resin composition includes: a thermosetting resin (A) containing an epoxy resin, a curing agent (B), and an inorganic filler (C); with respect to the total value of 100% by mass of the fixing resin composition, the content of the inorganic filler (C) is 50% by mass or more, and with respect to the fixing resin composition, the concentration of ionic impurities is 500 ppm or less, and the ionic impurities are at least one or more selected from alkali metal ions, alkaline earth metal ions, and halogen ions. CN104136532A discloses a resin composition for fixing a rotor, which includes a thermosetting resin containing an epoxy resin, a curing agent, and an inorganic filler; the epoxy resin includes at least one selected from biphenyl type epoxy resins, phenol aralkyl type epoxy resins, phenol novolac type epoxy resins, o-cresol novolac type epoxy resins, diphenol type epoxy resins, dinaphthol type epoxy resins, dicyclopentadiene type epoxy resins, dihydroanthracene diol type epoxy resins, and triphenylmethane type epoxy resins; the curing agent includes at least one selected from linear phenol resins, phenol aralkyl resins, naphthol type phenol resins, and phenol resins obtained by reacting hydroxybenzaldehyde, formaldehyde, and phenol. CN102408545A discloses a resin composition for sealing a rare earth permanent magnet coreless energy-saving motor, which includes an epoxy resin, a phenolic resin, a curing accelerator, a coupling agent, a stress reliever, a coloring agent, a flame retardant, a release agent, an inorganic filler, and a glass fiber filler.

[0004] However, none of the above-mentioned prior arts solve the defect that it is difficult to improve the rotor magnetic flux of the motor rotor fixing material. In particular, since the actual working temperature of the rotor is in a high-temperature environment of 140 - 180 °C, it is more difficult to achieve the improvement of the magnetic flux in the high-temperature environment. For the use of such fixing materials, the performance test at high temperature can reflect the situation in the actual use of new energy vehicles. Therefore, it is necessary to re-evaluate various performances of the rotor fixing material at high temperature, feedback a more realistic use environment, and make targeted improvements to the fixing material. Summary of the Invention

[0005] The purpose of the present invention is to provide an adhesive for a motor rotor that can improve the rotor magnetic flux without affecting other performances, so that the whole rotor has better magnetizable performance, so as to expand the applicable range of the epoxy resin for fixing the rotor, especially in improving the magnetic flux characteristics at high temperature. To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A motor rotor magnetic adhesive for improving high-temperature magnetic flux, comprising raw materials in the following parts by mass: 5-15 parts of epoxy resin, 1-3 parts of phenolic resin, 0.5-2 parts of curing accelerator, 15-30 parts of fused spherical silica, 40-60 parts of fused angular silica, 4-10 parts of fumed silica, and 3-30 parts of magnetic powder; the D50 of the fused spherical silica is 5-9 μm, the D50 of the fused angular silica is 15-21 μm, and the specific surface area of the fumed silica is 230-280 m 2 / g.

[0007] The epoxy resin is used to provide the cohesion and bonding strength of the system, so that the system has sufficient bonding performance and plays a main fixing effect. The filler components are mainly inorganic particles. Under the action of the fixing components, the filler components of the present invention can form an overall strength, providing support, hardness and stiffness. By using the added magnetic material powder, the effect of improving the magnetic flux can be achieved, so that the rotor as a whole has better magnetic flux and magnetic induction performance after being fixed, thereby improving the overall magnetism of the rotor and reducing the loss of the fixing material to the rotor and the interference of the curing material to the magnetism. Compared with the fixing methods of magnetic powder slurry or magnetic steel, the method of the present invention has a simple process, requires a lower processing temperature, has good material stiffness, is not easy to deform, and can withstand a higher rotational speed, so it has a better application prospect.

[0008] Furthermore, the magnetic powder includes at least one of sintered neodymium iron boron material and samarium cobalt material; the sintered neodymium iron boron material is prepared by calcining the neodymium iron boron material at 1100-1300 °C for 3-5 h and then tempering at 500-600 °C for 1-2 h. The purpose of calcination is to make the powder particles combine densely, eliminate pores, form a high-density magnet, and improve the mechanical strength; the purpose of tempering is to adjust the grain boundary phase distribution.

[0009] The inventors found that directly adding a small amount of magnetic powder to an epoxy resin thermosetting system could not improve the magnetic flux of the fixing material as expected. The possible reasons are that the dispersion of the magnetic powder is not good, the orientation does not reach the ideal state, the magnetic flux distribution is uneven, and local demagnetization occurs; it may also be due to the poor fluidity of silica, making it difficult to achieve the purpose of increasing the magnetic flux. In addition, the inventors also found that at high temperatures, the contribution of adding magnetic powder to the magnetic flux is even less. If the purpose of increasing the magnetic flux is to be achieved, a relatively large amount of magnetic powder needs to be added, which will cause a significant increase in the cost of such materials and a decrease in their industrial practical value. Therefore, achieving a high magnetic flux increase with a low magnetic powder addition amount is an urgent problem to be solved. The addition of magnetic powder has limited effect on increasing the magnetic flux in a high-temperature environment because the magnetic powder will demagnetize at high temperatures, and the thermal expansion coefficient of silica does not match that of epoxy resin and magnetic materials at temperatures above 150 °C, resulting in the relaxation of the fixing structure for fixing the magnetic powder, the destruction of the original orientation structure, and a decrease in magnetic flux. Increasing the Tg of the epoxy resin can improve this phenomenon, but this means increasing the crosslinking density of the epoxy resin, making the material more rigid and resulting in poorer toughness, and it is prone to fatigue failure under high and low temperature cyclic loads, which has an adverse effect on the long-term stability of the rotor fixing material. Therefore, unilaterally increasing the Tg of the epoxy resin is not advisable. Moreover, most of the currently used epoxy resins are commercial products, and it is not easy to find a suitable high-Tg epoxy resin. Therefore, when using existing epoxy resins, it is also of great significance and commercial value to weaken the adverse effect of the epoxy resin thermosetting rotor fixing material on the magnetic flux at high temperatures. The inventors unexpectedly found that the synergistic compounding and common action of three non-magnetic fillers, namely fused spherical silica of different sizes, fused angular silica, and fumed silica, can improve the effect of magnetic powder on increasing the magnetic flux in a high-temperature environment. When the addition amount of magnetic powder accounts for 3 wt% of the fixing material, there is a significant effect of increasing the magnetic flux. If the above-mentioned compounded non-magnetic fillers are not used, an addition amount of more than 10 wt% is required to have a suitable effect of increasing the magnetic flux. All three fillers are common reagents on the market that are inexpensive and commercially available, which facilitates the industrial application of the fixing material of the present invention. Currently, the reason for the increase in magnetic flux by the combination of the three fillers is unknown. The possible reason is that the compounded non-magnetic fillers have suitable fluidity, and the combination of spherical silica and angular silica with appropriate sizes and proportions. Among them, spherical silica spherical particles are usually easier to closely pack than angular particles, improving the overall density, thereby making the magnetic powder closer, reducing the spacing, and increasing the magnetic flux; angular silica forms a supporting structure, reducing sedimentation and improving the arrangement of the magnetic powder. The rough surface of angular silica is also beneficial to the interaction with the resin. The addition of fumed silica, in synergy with the spherical / angular silica filler, forms a multi-scale filling structure, further reducing the interfacial stress concentration caused by a single particle size. However, the addition amount of fumed silica needs to be strictly controlled, otherwise it will have an adverse effect instead.The combination of spherical silica and angular silica with appropriate sizes and proportions also needs to consider the cooperation with the fluidity of the resin. In the present invention, a certain proportion of silane coupling agent is added, which can strengthen the affinity between the resin and silica and improve the interfacial bonding between the magnetic powder and the resin.

[0010] Further, the motor rotor magnetic adhesive comprises the following raw materials in parts by mass: 9-13 parts of epoxy resin, 1.2-1.7 parts of phenolic resin, 0.8-1.3 parts of curing accelerator, 18-26 parts of molten spherical silica, 45-55 parts of molten angular silica, 5-8 parts of fumed silica, 1-3 parts of silane coupling agent, and 5-20 parts of magnetic powder.

[0011] Preferably, the magnetic powder is a mixture of sintered neodymium iron boron material and samarium cobalt material; and when adding the mixture of sintered neodymium iron boron material and samarium cobalt material, the raw materials of the motor rotor magnetic fixing material further comprise 2.2-3.0 parts of boron nitride nanosheets.

[0012] More preferably, in the magnetic powder, the mass ratio of the sintered neodymium iron boron material to the samarium cobalt material is 1:1-3; the size of the boron nitride nanosheets is 100-500 nm, and the thickness is 10-50 nm; more preferably, the size of the boron nitride nanosheets is 100-200 nm, and the thickness is 10-30 nm.

[0013] The neodymium iron boron material itself has strong magnetism, strong rigidity and low thermal expansion coefficient, but its Curie temperature is relatively low, the temperature stability is not good, and it is easy to demagnetize at high temperatures; in addition, the neodymium iron boron material is easy to be oxidized, so a passivation layer is formed on the surface after sintering for use. The samarium cobalt material has good temperature stability and corrosion resistance. The two materials have their own advantages and disadvantages in performance, but generally the sintered neodymium iron boron material and the samarium cobalt material cannot be added at the same time, otherwise the characteristic disadvantages will be prominent, but the advantages will not be obvious. The inventor unexpectedly found that by adding a small amount of boron nitride nanosheets, the two magnetic powders can be used in combination to improve the magnetic flux at high temperatures without bringing adverse effects. The inventor speculates that the possible reasons are that the boron nitride nanosheets play the role of a rheology regulator and form a thixotropic network in the resin; it may also be because the thermal expansion coefficient of boron nitride is close to that of neodymium iron boron, which can reduce the interfacial thermal stress during curing and cooling; or both factors play a role.

[0014] Further, the epoxy resin is selected from at least one of phenolic epoxy resin, bisphenol epoxy resin, biphenyl epoxy resin, dicyclopentadiene epoxy resin; the phenolic resin is selected from at least one of linear phenolic resin, biphenyl phenolic resin, naphthalene phenolic resin, polybenzonitrile phenolic resin, aralkyl phenol phenolic resin; the curing accelerator is selected from imidazole accelerators (such as 2-methylimidazole, 2-ethyl-4-methylimidazole), tertiary amine accelerators (such as triethylamine), 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0015] The silane coupling agent is an epoxy-based silane coupling agent, such as γ-glycidoxypropyltrimethoxysilane.

[0016] Furthermore, the motor rotor magnetic adhesive for improving high-temperature magnetic flux further comprises the following auxiliary materials in parts by mass: 0-2 parts of an ion scavenger, 0-2 parts of a demolding agent, 0-5 parts of a flame retardant, 0-2 parts of a toughening agent, 0-5 parts by mass of a colorant, and the parts by mass of the foregoing auxiliary materials are not all 0 at the same time. Preferably, the parts by mass of the ion scavenger are 0.1-1 part, and / or the parts by mass of the demolding agent are 0.1-1 part, and / or the parts by mass of the flame retardant are 1-5 parts, and / or the parts by mass of the toughening agent are 0.1-1 part, and / or the parts by mass of the colorant are 1-3 parts. The dosage and types of the auxiliary materials are well-known to those skilled in the art. For example, the ion scavenger is selected from alumina, magnesia or a combination thereof; the demolding agent is selected from montan wax, fatty acid esters, organosilicon oils or a combination thereof; the flame retardant is selected from metal hydroxides, oxides of organophosphorus compounds or a combination thereof; the toughening agent is selected from liquid carboxyl-terminated nitrile rubber, liquid hydroxyl-terminated nitrile rubber, liquid amino-terminated nitrile rubber, liquid polyether diol, liquid polysiloxane and a combination thereof; the colorant is selected from carbon black, iron oxide yellow, benzidine orange. In a preferred technical solution of the present invention, the total mass of the auxiliary materials does not exceed 10 wt% of the motor rotor magnetic fixing material.

[0017] The present invention also provides a preparation method of the above-mentioned motor rotor magnetic adhesive for improving high-temperature magnetic flux, comprising the following steps:

[0018] Weigh each raw material according to parts by mass, mix them evenly under an inert atmosphere to obtain a powder, heat and press it into a mold, and then crush it to obtain a powder product with a particle size of 1-10 mm; preferably, the particle size of the powder product is 3-5 mm.

[0019] The present invention also provides a motor rotor, comprising a rotor body, a permanent magnet, and the above-mentioned magnetic adhesive for fixing the rotor body and the permanent magnet. By using the magnetic flux formed after the material is magnetized, the interference caused by the fixing material to the motor can be effectively reduced. Description of the Drawings

[0020] Figure 1 It is a photo of the adhesive powder compressed into a cylindrical cake;

[0021] Figure 2 It is a photo of the whole motor rotor fixed by the adhesive. Detailed Embodiments

[0022] The solutions in the present invention are further elaborated through the following specific embodiments.

[0023] Experiment 1

[0024] In this embodiment, the influence of the presence of magnetic material powder in the filler component on the system was mainly verified. An example containing magnetic material powder and a comparative example without magnetic material powder were involved, and the component ratios of each group are shown in Table 1.

[0025] Among them, the D50 of fused spherical silica is 6.2 μm, the D50 of fused angular silica is 17.8 μm, and the BET of fumed silica is 240 m 2 / g. The sintered neodymium iron boron magnetic powder is obtained by calcining neodymium iron boron material at 1200 °C for 3 h and then tempering at 600 °C for 2 h.

[0026] Table 1 Motor Rotor Magnetic Adhesive Formulation

[0027]

[0028] In Table 1 above, the colorant is carbon black, and the final product is black. The ion scavenger is alumina. Epoxy resins 1 and 2 are two different o-cresol type epoxy resins. Among them, epoxy resin 1 is NPCN-704 (Nan Ya Plastics Corporation), and epoxy resin 2 is Nan Ya NPCN-703 (Nan Ya Plastics Corporation). Phenolic resin 1 is bisphenol A type phenolic resin, phenolic resin 2 is polybenzonitrile type phenolic resin, the curing accelerator is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), the colorant is carbon black, the ion scavenger is alumina, the toughening agent is liquid carboxyl-terminated nitrile rubber, the flame retardant is resorcinol bis(diphenyl phosphate), the mold release agent is propyl fumarate, and the silane coupling agent is γ-glycidoxypropyltrimethoxysilane.

[0029] The performance of the adhesive in Experiment 1 above was tested, and the results are shown in Table 2.

[0030] Glass transition temperature: SJ-T11197-2013;

[0031] Coefficient of thermal expansion (α1): SJ-T11197-2013;

[0032] Flexural strength: GBT 1449-2005.

[0033] Weigh each raw material according to the formulation in Table 1, mix them evenly under a nitrogen atmosphere to obtain a powder, heat and press it into a shape, and then crush it to obtain a powder product with a particle size of 3-5 mm. The powder is compressed into a cylindrical cake (as follows Figure 1), The high-frequency preheating machine preheats the cake material to 90°C, puts the preheated cake material into the mold and heats it to 190°C to make the plastic part of it molten and have fluidity. Apply a pressure of 10 MPa through the hydraulic system, and squeeze the fluid adhesive into the gap between the permanent magnet and the rotor core (where the permanent magnets are arranged according to polarity and embedded in the rotor core slots, preheated to 100°C), ensuring that the material evenly coats the surface of the permanent magnet and fills the slots. The extrusion speed is controlled between 10 and 20 mm / s. The mold temperature is controlled at 150°C and cured for 10 minutes to form a high-strength cross-linked structure (finished products such as Figure 2 ). The test of magnetic flux refers to IEC60404, and measures the magnetic flux of the whole rotor after magnetization. The magnetic flux test method is IEC 60404, and the test temperature is 180°C.

[0034] Table 2 Performance Test of Magnetic Adhesive for Motor Rotor

[0035]

[0036] It can be seen from the above experimental data that after adding neodymium iron boron magnetic powder, the magnetic flux of the system can be improved, and there is no obvious influence on the bending strength and coefficient of thermal expansion. While maintaining good mechanical strength as much as possible, the magnetic flux can be improved. However, considering mechanical properties and cost, the total added mass of magnetic materials should not exceed 30% of the total mass, preferably not exceeding 20% of the total mass. It should be noted that in the above materials, the added amount of the filler component (that is, the sum of the magnetic flux component and the non-magnetic flux component) should be controlled within the range of 75-90% by weight. If the added amount of the filler component is too much, the internal bonding performance of the system will become poor, and if the added amount is too little, the hardness of the system will be insufficient. The compounding of various non-magnetic fillers, that is, the compound mixing of fused spherical silica, fused angular silica, and fumed silica according to specific sizes and specific ratios, can synergistically improve the magnetic flux of the fixed material after adding magnetic powder at high temperatures. By comparing Samples 1-7 and 1-12, it is found that the addition of epoxy-based silane coupling agent can further improve the magnetic flux.

[0037] Experiment 2

[0038] After comprehensively considering the experimental groups in Experiment 1, select the experimental group 1-7 with the best comprehensive performance. On this basis, screen the dosage and types of non-magnetic fillers, that is, silica. To adjust the mass ratio of fused spherical silica, fused angular silica, and fumed silica, as well as parameters such as size, and keep the ratios and types of the remaining components unchanged, as shown in Table 3 specifically.

[0039] Among Samples 2-5, the D50 of fused spherical silica (a1) is 5.1 μm, and the D50 of fused angular silica (b1) is 15.0 μm; in Sample 2-6, the D50 of fused spherical silica (a2) is 8.7 μm, and the D50 of fused angular silica (b2) is 20.3 μm; in Sample Comparative Example 5, the D50 of fused spherical silica (a3) is 4.2 μm, and the D50 of fused angular silica (b3) is 13.5 μm; in Sample Comparative Example 6, the D50 of fused spherical silica (a4) is 10.0 μm, and the D50 of fused angular silica (b4) is 25.0 μm.

[0040] Table 3 Motor Rotor Magnetic Adhesive Formulation

[0041]

[0042] Performance tests were conducted on each motor rotor magnetic fixing material in Table 3, and the results are shown in Table 4. The differences in glass transition temperature and coefficient of thermal expansion are very small, so they are not listed in Table 4.

[0043] Table 4 Motor Rotor Magnetic Adhesive Performance Test

[0044]

[0045] Based on the above experimental results, by adjusting the composition of silica, relatively good magnetic flux can be obtained without changing the addition amount of magnetic materials. However, the particle sizes of fused spherical silica and fused angular silica need to be controlled to effectively improve the magnetic flux of the adhesive at high temperatures.

[0046] Experiment 3

[0047] Other conditions are the same as in Experiment 1. In Experiment 3, the magnetic powder is a mixture of sintered neodymium iron boron magnetic powder and samarium cobalt magnetic powder. The formulation is shown in Table 5 below. The size of the boron nitride nanosheets used is about 300 ± 50 nm, and the thickness is about 30 nm.

[0048] Table 5 Motor Rotor Magnetic Adhesive Formulation

[0049]

[0050] Performance tests were conducted on each motor rotor magnetic fixing material in Table 5, and the results are shown in Table 6. The differences in glass transition temperature and coefficient of thermal expansion are very small, so they are not listed in Table 6.

[0051] Table 6 Motor Rotor Magnetic Adhesive Performance Test

[0052]

[0053] It can be seen that when both sintered NdFeB magnetic powder and SmCo magnetic powder are added, the magnetic flux will instead decrease. The addition of boron nitride nanosheets is required to significantly increase the high-temperature magnetic flux.

Claims

1. A magnetic adhesive for improving high temperature magnetic flux of a motor rotor, characterized in that: The invention comprises the following raw materials in parts by weight: 5-15 parts of epoxy resin, 1-3 parts of phenolic resin, 0.5-2 parts of curing accelerator, 15-30 parts of fused spherical silica, 40-60 parts of fused angular silica, 4-10 parts of fumed silica, and 3-30 parts of magnetic powder; the D50 of the fused spherical silica is 5-9 μm, the D50 of the fused angular silica is 15-21 μm, and the specific surface area of ​​the fumed silica is 230-280 m 2 / g; the magnetic powder includes at least one of sintered NdFeB material and SmCo material; the sintered NdFeB material is obtained by calcining the NdFeB material at 1100-1300°C for 3-5h and then tempering it at 500-600°C for 1-2h.

2. The motor rotor magnetic adhesive according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 9-13 parts of epoxy resin, 1.2-1.7 parts of phenolic resin, 0.8-1.3 parts of curing accelerator, 18-26 parts of fused spherical silica, 45-55 parts of fused angular silica, 5-8 parts of fumed silica, 1-3 parts of silane coupling agent and 5-20 parts of magnetic powder.

3. The motor rotor magnetic adhesive according to claim 1, characterized in that: The magnetic powder includes a mixture of sintered NdFeB material and SmCo material; and when the mixture of sintered NdFeB material and SmCo material is added, the raw material of the motor rotor magnetic adhesive also includes 2.2-3.0 parts by mass of boron nitride nanosheets.

4. The motor rotor magnetic adhesive according to claim 3, characterized in that: In the magnetic powder, the mass ratio of sintered NdFeB material to SmCo material is 1:1-3; the size of boron nitride nanosheets is 100-500nm, and the thickness is 10-50nm.

5. The motor rotor magnetic adhesive according to claim 1, characterized in that: The epoxy resin is selected from at least one of phenolic epoxy resin, bisphenol epoxy resin, biphenyl epoxy resin, and dicyclopentadiene epoxy resin; the phenolic resin is selected from at least one of linear phenolic resin, biphenyl phenolic resin, naphthyl phenolic resin, polybenzonitrile phenolic resin, and aralkylphenol phenolic resin; the curing accelerator is selected from imidazole accelerators and tertiary amine accelerators.

6. The motor rotor magnetic adhesive according to claim 1, characterized in that: The invention also includes the following auxiliary materials in parts by weight: 0-2 parts of ion capture agent, 0-2 parts of mold release agent, 0-5 parts of flame retardant, 0-2 parts of toughening agent, 0-5 parts by weight of colorant, and the parts by weight of the aforementioned auxiliary materials are not all 0 at the same time.

7. The method for preparing the magnetic adhesive for improving high temperature magnetic flux of a motor rotor according to any one of claims 1 to 6, characterized in that: The following steps are involved: The raw materials are weighed according to their mass parts, mixed evenly under an inert atmosphere to obtain powder, heated and pressed into shape, and crushed to obtain a powder product with a particle size of 1-10 mm.

8. A motor rotor, characterized in that: The invention comprises a rotor body, a magnetic steel, and a motor rotor magnetic adhesive as described in any one of claims 1 to 6 for fixing the rotor body and the magnetic steel.

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