CN106199468B - Evaluation method for magnetic properties of bonded permanent magnetic ferrite magnetic powder - Google Patents
Evaluation method for magnetic properties of bonded permanent magnetic ferrite magnetic powder Download PDFInfo
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- CN106199468B CN106199468B CN201610576502.8A CN201610576502A CN106199468B CN 106199468 B CN106199468 B CN 106199468B CN 201610576502 A CN201610576502 A CN 201610576502A CN 106199468 B CN106199468 B CN 106199468B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/12—Measuring magnetic properties of articles or specimens of solids or fluids
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/0266—Moulding; Pressing
Abstract
the invention relates to an evaluation method for magnetic properties of bonded permanent magnetic ferrite magnetic powder, which is characterized by comprising the following steps: molding the bonded permanent magnetic ferrite magnetic powder into a multi-pole magnetic part in an apparatus for manufacturing the multi-pole magnetic part, and evaluating the magnetic characteristics of the bonded permanent magnetic ferrite magnetic powder by measuring the magnetic characteristics of the multi-pole magnetic part; wherein the device for manufacturing the multi-pole magnetic component comprises at least two orientation magnets distributed on an annular base formed by non-magnetic conducting materials, and the at least two orientation magnets are used for enabling the multi-pole magnetic component in the annular base to form multi-pole magnetic characteristics in a magnetic field in a fixed mode on the annular base. The bonded permanent magnetic ferrite magnetic powder is injection molded into a multi-pole component to test the surface magnetic field and the magnetic flux, the magnetic characteristics are evaluated through the surface magnetic field and the magnetic flux, the evaluation result is more accurate and effective, and the requirement of manufacturers on knowing the surface magnetic field and the magnetic flux of the magnetic powder is met.
Description
Technical Field
the invention relates to the technical field of bonded permanent magnetic ferrite magnetic powder, in particular to an evaluation method for magnetic properties of bonded permanent magnetic ferrite magnetic powder.
Background
In 1933, cang and wu jing developed cubic system cobalt ferrite, and opened the research preface of permanent magnetic ferrite oxide, and then barium ferrite and strontium ferrite appeared in succession, so that permanent magnetic ferrite material has become indispensable basic material in every industrial production field. At present, permanent magnetic ferrite can be divided into sintering permanent magnet and bonding permanent magnet according to a forming process, wherein the sintering permanent magnet is prepared by adopting a traditional powder metallurgy process, and the bonding permanent magnet is prepared by adopting a calendaring or injection molding process.
The bonded magnet is a composite material prepared by uniformly mixing magnetic powder, a binder and other additives according to a certain proportion and adopting a proper forming process. It has the characteristics of both magnet and plastics, and can be formed by adopting common plastics processing equipment and forming method. Although the bonded magnet has low magnetic properties and poor heat resistance as compared with a sintered magnet, it has the following advantages:
(1) The product processing method is as follows: such as calendering, extrusion, injection, molding;
(2) the product has a large degree of freedom in shape: such as rings, posts, sheets, blocks, tiles, and other various complex shapes;
(3) the product has high dimensional precision and does not need secondary processing;
(4) Can be integrally formed with other components to form a composite product;
(5) The process is simple, mass automatic production can be realized, and the efficiency is high;
(6) The finished product rate of the product is high and can reach about 95 percent;
(7) The product has good machinability and easy assembly, and is not easy to break and desquamate;
(8) By adjusting the proportion of the magnetic powder and the binder, products with different physical and chemical properties can be prepared.
Based on the above advantages, bonded magnets have been rapidly developed in recent years.
Injection molding is an important method for forming bonded permanent magnet materials.
The injection molding is to mix the magnetic powder, the adhesive and the auxiliary agent according to a certain proportion, to prepare granules through mixing and granulation, then to perform injection molding under certain technological parameters, and to obtain the product after cooling.
In the injection molding process, the granular material is in a molten state, the flowability is good, and the magnetic powder with uniaxial anisotropy easily rotates under the action of an oriented magnetic field, so that the injection process is more suitable for forming an anisotropic bonded magnet.
Although the magnetic performance of the injection bonded magnet is lower than that of the molded bonded magnet, the production efficiency is high, and the degree of freedom of the shape of the product is large. In addition, because the content of the added adhesive is large (the volume fraction is more than 30 percent), an adhesive film is formed on the surface of the magnet, the corrosion resistance of the magnet is improved, and the surface corrosion prevention treatment can not be carried out generally.
Magnetic powder is a key factor for determining the magnetic performance of an injection molded magnet, and effective testing and evaluation methods are required for evaluating the magnetic properties of the magnetic powder. At present, the detection and evaluation method of injection molding ferrite magnetic powder mainly comprises the steps of uniformly mixing the magnetic powder with a bonding agent, granulating ferrite granules by a double-screw extruder, using the granules to perform injection molding on a magnetic field orientation molding machine to form a ferrite cylinder, testing the remanence (Br), the magnetic coercive force (Hcb), the intrinsic coercive force (Hcj) and the maximum magnetic energy product (BH) max of a cylinder sample, preparing different magnetic powders by adopting the same formula and process to obtain a cylinder experimental block, and representing the magnetic performance of the magnetic powder by the four indexes.
However, in the production and use processes, a magnetic device manufacturer pays more attention to the surface field and the magnetic flux of the device, although four performance indexes (remanence (Br), magnetic induction coercivity (Hcb), intrinsic coercivity (Hcj) and maximum magnetic energy product (BH) max) tested by a traditional test method have certain influence on the surface field of the device, the surface field of the device has a plurality of influence factors, an accurate corresponding relation does not exist, even the difference between the four performance indexes of a magnetic powder injection standard sample is not large sometimes, but the surface field and the magnetic flux of the final device are greatly different, so that the existing method for representing the magnetic powder has certain limitation.
The differences between the sample shape testing parameters of the actual product and the test sample are shown in table 1:
Table 1: differences between the existing samples and the multipole device
| Orientation magnetic field/Gs | Device with a metal layer | test parameters | |
| Test standard sample | ＞9000 | Bipolar cylinder | Br、Hcb、Hcj、(BH)max |
| Multipole device | 1500～3000 | Multi-pole magnetic ring | Surface magnetic field, magnetic flux |
The magnetic powder orientation magnetic field difference between the two magnetic powder orientation magnetic fields, the test standard sample adopts the electromagnetic coil orientation, the orientation magnetic field is high and reaches 9000Gs, the magnetic powder is almost completely oriented, the multi-pole device is influenced by the space of the die, the permanent magnet orientation is adopted, the orientation magnetic field is low (1500-plus-3000 Gs), the magnetic powder orientation is low, and the magnetic performance of the magnetic powder is not completely exerted. Particularly, for the formula with higher volume fraction of magnetic powder in the detection formula, such as the formula with more than 2.0MGOe, the difference caused by the two test methods is more obvious.
The invention provides an evaluation method for magnetic properties of bonded permanent magnetic ferrite magnetic powder, which characterizes the magnetic properties of the magnetic powder by testing a surface field and magnetic flux, makes up for the defects of the traditional evaluation method for the magnetic properties and has greater practical properties.
Chinese patent (CN 103930775 a) discloses a magnetic material evaluation method for evaluating a magnet using a magnetic material evaluation device, the magnetic material evaluation device comprising: an excitation coil that generates a magnetic field having a size corresponding to a region including at least one magnetic piece of the magnet in which a plurality of magnetic pieces are joined to each other with an insulator interposed therebetween and the insulator between the magnetic piece and another adjacent magnetic piece; and a detection coil having a coil diameter smaller than a length of one of the magnetic pieces in an arrangement direction of the magnetic pieces, the magnetic body evaluation method comprising: obtaining a threshold value of an eddy current amount in advance from a relationship between an eddy current generated in the magnet and a heat generation amount; and applying a magnetic field generated by the excitation coil to the magnet, and determining that the magnet is defective when the amount of eddy current detected by the detection coil exceeds the threshold value. Although this patent can evaluate the magnetic field and magnetism of the magnetic body, it cannot effectively evaluate the surface magnetic field and magnetic flux formed by the magnetic powder.
disclosure of Invention
Aiming at the defects of the prior art, the invention provides an evaluation method for the magnetic property of bonded permanent magnetic ferrite magnetic powder, which is characterized by comprising the following steps:
The bonded permanent magnetic ferrite magnetic powder is molded into a multi-pole magnetic part in an apparatus for manufacturing the multi-pole magnetic part,
evaluating the magnetic characteristics of the bonded permanent magnetic ferrite magnetic powder by measuring the magnetic characteristics of the multi-pole magnetic part; wherein the content of the first and second substances,
The device for manufacturing the multi-pole magnetic component comprises at least two oriented magnets distributed on an annular base formed by non-magnetic conducting materials, and the at least two oriented magnets are used for enabling the multi-pole magnetic component in the annular base to form multi-pole magnetic characteristics in a magnetic field in a fixed mode on the annular base.
according to a preferred embodiment, the bonded permanent magnetic ferrite magnetic powder having uniaxial anisotropy is injected in a molten state into an injection mold within the annular base and is rotationally molded under the action of a magnetic field into a multi-pole magnetic part having multi-pole magnetic characteristics.
According to a preferred embodiment, the melting temperature of the bonded permanent magnetic ferrite magnetic powder is 250-300 ℃, wherein the heating temperature of the bonded permanent magnetic ferrite magnetic powder passing through five parts of an injection instrument in the injection molding process is as follows in sequence: 260 deg.C, 270 deg.C, 280 deg.C, 290 deg.C, 300 deg.C.
Device for manufacturing a multi-polar magnetic component, characterized in that it comprises at least two oriented magnets distributed on a hollow annular base made of non-magnetically conductive material for forming in a fixed manner on said annular base a multi-polar magnetic characteristic in a magnetic field of the multi-polar magnetic component inside the annular base, at least two detents being provided on the outside of said annular base for removably fixing said oriented magnetic field.
According to a preferred embodiment, at least two of the orienting magnets are uniformly distributed radially in an equidistant manner on the detent of the annular base.
According to a preferred embodiment, the distribution of the oriented magnets is non-uniform, and the oriented magnets are fixed on the detent of the annular base according to a non-uniform distribution law.
According to a preferred embodiment, the annular base comprises a circular ring base, a rectangular ring base or a regular polygonal ring base.
a multipolar magnetic component characterized in that the multipolar magnetic component is molded from a bonded permanent ferrite magnetic powder in an injection mold for producing a multipolar magnetic component, the magnetic properties of the bonded permanent ferrite magnetic powder being evaluated by measuring the magnetic properties of the multipolar magnetic component; wherein the content of the first and second substances,
The multipole magnetic component is integrally formed and comprises a first circular ring, a second circular ring and at least two spokes, wherein the first circular ring and the second circular ring are coaxially arranged, the inner diameter of the second circular ring is larger than the outer diameter of the first circular ring, the spokes are connected with the first circular ring and the second circular ring, and the height of the first circular ring is larger than that of the second circular ring.
According to a preferred embodiment, the spokes are distributed radially and the central extension lines of the spokes converge to a point on the axle center of the first ring; or
The spokes are distributed in a radiation manner, and the central extension lines of the spokes do not converge on the axis of the first ring; or
The spokes are uniformly distributed between the first circular ring and the second circular ring in a mode that a central extension line and a tangent of the outer diameter of the first circular ring form the same angle.
According to a preferred embodiment, the first ring and the second ring of the multipole magnetic member have a planar circular cross section, the spokes comprise circular, rectangular and/or polygonal bars, and the circular bars further comprise constant-diameter bars and variable-diameter bars.
The invention has the beneficial technical effects that:
The bonded permanent magnetic ferrite magnetic powder is injection molded into a multi-pole magnetic component to test the surface magnetic field and the magnetic flux, the magnetic characteristics are evaluated through the surface magnetic field and the magnetic flux, the evaluation result is more accurate and effective, and the requirement of manufacturers on knowing the surface magnetic field and the magnetic flux of the magnetic powder is met. The invention can accurately evaluate the magnetic property of the bonded permanent magnetic ferrite magnetic powder and provides a quick, simple and convenient detection method for preparing high-performance bonded permanent magnetic ferrite magnetic powder from magnetic powder.
drawings
FIG. 1 is a logic diagram of the evaluation method of the present invention;
FIG. 2 is a schematic top view of a sixteen pole magnetic ring device of the present invention;
FIG. 3 is a schematic longitudinal side view of a sixteen pole magnetic ring device of the present invention;
FIG. 4 is a schematic view of an apparatus for fabricating a multi-pole magnetic component of the present invention;
FIG. 5 is a schematic view of the magnetic flux testing tool of the present invention; and
fig. 6 is a surface field distribution graph of a sixteen-pole magnetic ring of the present invention.
Attached icons and lists
1: orientation magnet 2: sixteen-pole magnetic ring 3: circular ring base
Detailed Description
The following detailed description is made with reference to the accompanying drawings.
The permanent magnetic material is a material which can still keep stronger magnetism after being magnetized by an external magnetic field and the external magnetic field is removed. The magnetic properties of the present invention refer to magnetic flux and surface magnetic field.
H of magnetic material under the same detection conditionscjThe requirement of a threshold value is met, and the higher the general test magnetic flux and the surface field are, the better the magnetic powder performance is. Therefore, the present invention evaluates the magnetic properties of the bonded permanent magnetic ferrite magnetic powder by measuring the magnetic properties of the multi-pole magnetic part molded from the bonded permanent magnetic ferrite magnetic powder.
The multi-pole magnetic member in the present invention means a magnetic member having a number of magnetic poles greater than 1.
The oriented magnet in the present invention means a bar magnet having magnetic properties. One end of the orientation magnet is S pole, and the other end is N pole. The orientation magnet may be a rectangular bar magnet or a cylindrical magnet. The orientation magnet can be a solid magnet or a hollow magnet with a hollow center.
the invention provides an evaluation method for magnetic properties of bonded permanent magnetic ferrite magnetic powder, which is characterized by comprising the following steps:
The bonded permanent magnetic ferrite magnetic powder is molded into a multi-pole magnetic part in an apparatus for manufacturing the multi-pole magnetic part,
evaluating the magnetic characteristics of the bonded permanent magnetic ferrite magnetic powder by measuring the magnetic characteristics of the multi-pole magnetic part; wherein the content of the first and second substances,
The apparatus for manufacturing a multi-pole magnetic component includes at least two oriented magnets distributed on an annular base formed of a non-magnetically permeable material for fixedly imparting a multi-pole magnetic characteristic to the multi-pole magnetic component within the annular base in a magnetic field on the annular base. As shown in fig. 1, the method for evaluating the magnetic properties of the bonded permanent magnetic ferrite magnetic powder of the present invention includes:
S1: the bonded permanent magnetic ferrite magnetic powder is molded into a multi-pole magnetic part in an apparatus for manufacturing the multi-pole magnetic part.
S2: the magnetic properties of the bonded permanent magnetic ferrite magnetic powder were evaluated by measuring the magnetic properties of the multi-pole magnetic part.
The step of molding the bonded permanent magnetic ferrite magnetic powder into a multi-pole magnetic part in an apparatus for manufacturing a multi-pole magnetic part includes:
S11: mixing the surface treated permanent magnetic ferrite magnetic powder with a binder to form bonded permanent magnetic ferrite magnetic powder.
Specifically, the step of mixing the surface-treated permanent magnetic ferrite magnetic powder with a binder to form a bonded permanent magnetic ferrite magnetic powder includes:
Diluting KH-590 coupling agent with absolute ethanol to obtain 10% standard solution,
Mixing the permanent magnetic ferrite magnetic powder with the standard solution, and drying in a drying oven at 100 ℃ for 2 hours.
The surface treated permanent magnetic ferrite magnetic powder is mixed with a lubricant and a binder at a high speed to form bonded permanent magnetic ferrite magnetic powder, and the mixing ratio of the permanent magnetic ferrite magnetic powder to the lubricant to the binder is 100: 12: 1.
S12: and mixing and granulating the bonded permanent magnetic ferrite magnetic powder at a high temperature to form bonded permanent magnetic ferrite magnetic powder particles.
And extruding and granulating the bonded permanent magnetic ferrite magnetic powder by using a torque rheometer. Preferably, the high temperature for mixing and granulating the bonded permanent magnetic ferrite magnetic powder is 200-250 ℃. Wherein, the heating temperature of five parts passing through a granulating instrument in the process of mixing and granulating the bonded permanent magnetic ferrite magnetic powder is as follows in sequence: 210 deg.C, 240 deg.C, 220 deg.C. In the invention, the extrusion granulation rotating speed in the granulation process of the torque rheometer is 190 r/min. In the process of mixing and granulating, parameters of the processes of torque, extrusion pressure and material temperature are recorded and monitored so as to ensure the normal formation of the bonded permanent magnetic ferrite particles.
s13: the bonded permanent magnetic ferrite magnetic powder particles with uniaxial anisotropy are injected into an injection mold in an annular base in a molten state and are rotationally molded into a multi-pole magnetic component with multi-pole magnetic characteristics under the action of a magnetic field.
The bonded permanent magnetic ferrite magnetic powder particles were melted at a temperature of 270 ℃, and the melt index value of the bonded permanent magnetic ferrite magnetic powder in the molten state was tested.
And injecting the bonded permanent magnetic ferrite magnetic powder particles into an injection mould arranged in the annular base in a molten state and forming, so that the bonded permanent magnetic ferrite magnetic powder with uniaxial anisotropy rotates and is formed under the action of an oriented magnetic field.
Preferably, the injection temperature of the bonded permanent magnetic ferrite magnetic powder particles is 250-300 ℃. Wherein, the heating temperature of five parts of bonding permanent magnetic ferrite magnetic powder granule process injection instrument at injection moulding's in-process is in proper order: 260 deg.C, 270 deg.C, 280 deg.C, 290 deg.C, 300 deg.C.
the apparatus for manufacturing a multi-pole magnetic component of the present invention comprises at least two oriented magnets distributed on a hollow annular base formed of a non-magnetically conductive material. At least two orientation magnets are used to fixedly form a multi-pole magnetic feature in a magnetic field in a multi-pole magnetic component within the annular base on the annular base. At least two screens for fixing the orientation magnetic field in a detachable mode are arranged on the outer side of the annular base. The annular base comprises a circular ring base, a rectangular ring base or a regular polygonal ring base.
according to a preferred embodiment, the orienting magnets may be evenly distributed on the annular base. The distances between the oriented magnets are equal. For example, the orientation magnets are evenly distributed over the detents of the circular base.
According to a preferred embodiment, the distribution of the oriented magnets may be non-uniform. The orientation magnets can be fixed on the clamping position of the annular base according to the uneven distribution rule. For example, the pole distance between the poles of two oriented magnets includes a distance a and a distance B. The oriented magnets are distributed according to the rule that the magnetic pole distance is ABAB.
the multi-pole magnetic component is a multi-pole magnetic ring. The multi-pole magnet ring is formed from bonded permanent magnetic ferrite magnetic powder in an apparatus for manufacturing a multi-pole magnetic part, and the magnetic characteristics of the bonded permanent magnetic ferrite magnetic powder are evaluated by measuring the magnetic characteristics of the multi-pole magnetic part. The multi-pole magnetic ring comprises a first ring arranged coaxially, a second ring with the inner diameter larger than the outer diameter of the first ring and at least two spokes connecting the first ring and the second ring. The height of the first ring is greater than the height of the second ring.
After the multi-pole magnetic member is molded, it is necessary to detect the magnetic characteristics of the multi-pole magnetic member. The magnetic characteristic parameters measured by the invention comprise surface magnetic field parameters and magnetic flux parameters. The magnetic characteristics of the bonded permanent magnetic ferrite magnetic powder are evaluated by evaluating the surface magnetic field parameters and the magnetic flux parameters of the multi-pole magnetic component.
A magnetic flux parameter of the multi-pole magnetic component is measured. And arranging the multi-pole magnetic ring at the central position of the magnetic flux testing tool. At least two test poles are distributed in a radiation mode by taking the multi-pole magnetic ring as the center. And the test poles are wound by the insulated wires according to a right-hand spiral rule, the winding directions of the insulated wires of the adjacent test poles are opposite, the magnetic flux test tool is sealed, and the magnetic flux test is carried out to obtain the magnetic flux parameters of the multi-pole magnetic component.
Surface magnetic field parameters of the multi-pole magnetic component are measured. And measuring the surface magnetic field of the multipole magnetic component by using the surface magnetic field distribution system to obtain the surface magnetic field parameters of the multipole magnetic component.
the method selects at least one permanent magnetic ferrite magnetic powder, uses the evaluation method to manufacture a standard multi-pole magnetic component sample, and measures a remanence (Br) parameter, a magnetic induction coercivity (Hcb) parameter, an intrinsic coercivity (Hcj) parameter and a maximum magnetic energy product (BH) max) parameter. The oriented magnetic field of the standard multi-polar magnetic component sample is 9000Gs, and four parameter comparison results of the standard multi-polar magnetic component are evaluated.
The magnetic characteristic evaluation method has larger difference with the traditional magnetic characteristic method according to four parameters of a remanence (Br) parameter, a magnetic induction coercive force (Hcb) parameter, an intrinsic coercive force (Hcj) parameter and a maximum magnetic energy product (BH) max parameter. The invention can evaluate the magnetic flux of the magnetic powder of the bonded permanent magnetic ferrite and the surface magnetic field more accurately.
example 1
This example is a further illustration of the present invention.
This example evaluates the magnetic properties of the bonded permanent magnetic ferrite powder by measuring the magnetic properties of a sixteen-pole magnetic ring formed from the bonded permanent magnetic oxygen powder. The present embodiment is not limited to the sixteen-pole magnetic ring, and is also applicable to other multi-pole magnetic components.
Firstly, mixing the permanent magnetic ferrite magnetic powder subjected to surface treatment with a binder to form bonded permanent magnetic ferrite magnetic powder.
And carrying out surface treatment on the permanent magnetic ferrite magnetic powder. And (3) performing surface treatment on the ferrite magnetic powder by adopting a silane coupling agent KH-590. Preferably, 1kg of permanent magnetic ferrite magnetic powder is weighed, and 10ml of KH-590 coupling agent is diluted into 10% standard solution by using absolute ethyl alcohol; and uniformly mixing the permanent magnetic ferrite magnetic powder with the standard solution, and placing the mixed solution in a drying oven at 100 ℃ for drying for 2 hours for later use.
mixing the surface treated permanent magnetic ferrite magnetic powder with a binder to form bonded permanent magnetic ferrite magnetic powder. Preferably, the surface-treated permanent magnetic ferrite magnetic powder is mixed with a lubricant and a binder at a high speed to form a bonded permanent magnetic ferrite magnetic powder. The mixing ratio of the permanent magnetic ferrite magnetic powder to the lubricant to the binder is 100: 12: 1. Preferably, 1kg of the surface-treated permanent magnetic ferrite magnetic powder, 120g of nylon 12 and 10g of stearic acid amide lubricant are uniformly mixed in a high-speed mixer to form the bonded permanent magnetic ferrite magnetic powder.
And mixing and granulating the bonded permanent magnetic ferrite magnetic powder at a high temperature to form bonded permanent magnetic ferrite magnetic powder particles.
specifically, a torque rheometer is selected to carry out mixing granulation on the bonded permanent magnetic ferrite magnetic powder to form bonded permanent magnetic ferrite magnetic powder particles. And in the process of mixing and granulating, recording parameters such as torque, pressure, material temperature and the like in real time.
the heating part of the torque rheometer from the feeding end to the mouth mold is divided into five sections, and the heating temperature is 200-250 ℃. Wherein, the heating temperature of five parts passing through the torque rheometer in the process of mixing and granulating the bonded permanent magnetic ferrite magnetic powder is as follows in sequence: 210 deg.C, 240 deg.C, 220 deg.C.
the mixing and granulating process comprises the following steps:
a. Opening the equipment, sequentially setting the temperature from the feeding end to the neck mold, and performing extrusion granulation 30 minutes after the temperature of the equipment reaches the set temperature;
b. Carrying out zero clearing operation on the torque and the pressure of the equipment;
c. Adjusting the rotating speed of the screw to 190 revolutions per minute, and adjusting the feeding rotating speed of the equipment to 8 revolutions per minute; the torque rheometer dynamically records parameters such as torque, extrusion pressure, material temperature and the like in the granulation process in real time;
d. And after the granulation extrusion process is stable, continuously extruding for 20 minutes, and calculating the average torque, the average extrusion pressure and the like in a stable extrusion state according to the data of the time period stored on the equipment.
Preferably, four parts of permanent magnetic ferrite magnetic powder are selected to be molded into four sixteen-pole magnetic rings. The permanent magnetic ferrite magnetic powder numbers are 1#, 2#, 3#, and 4 #. The bonded permanent magnetic ferrite magnetic powder comprises a 17-type samarium cobalt permanent magnetic material ((BH) max is more than 28MGOe, Hcj is more than 20KOe) or a sintered neodymium iron boron permanent magnetic material (high intrinsic coercive force EH and UH series). The parameters of the mixing and granulating process of the bonded permanent magnetic ferrite magnetic powder are shown in table 1.
Table 1: parameters of mixing and granulating process
After the mixing granulation, the bonded permanent magnetic ferrite magnetic powder particles with uniaxial anisotropy are injected into an injection mould in an annular base in a molten state, and are rotationally molded into a multi-pole magnetic component with multi-pole magnetic characteristics under the action of a magnetic field.
Specifically, after the bonded permanent magnetic ferrite magnetic powder is subjected to a mixing granulation process to form bonded permanent magnetic ferrite magnetic powder particles, a melt index value of extrusion granulation is tested by using a melt index instrument. Preferably, the test temperature is 270 ℃ and the load is 5 kg. The melt index is shown in Table 2.
And injecting the bonded permanent magnetic ferrite magnetic powder particles into an injection mould arranged in the annular base in a molten state, so that the bonded permanent magnetic ferrite magnetic powder with uniaxial anisotropy rotates and is molded under the action of a magnetic field.
Preferably, the injection temperature of the bonded permanent magnetic ferrite magnetic powder particles is 250-300 ℃. Wherein, the heating temperature of five parts of bonding permanent magnetic ferrite magnetic powder granule process injection instrument at injection moulding's in-process is in proper order: 260 deg.C, 270 deg.C, 280 deg.C, 290 deg.C, 300 deg.C. Further preferably, the heating temperatures of the bonded permanent magnetic ferrite magnetic powder particles passing through the five parts of the injection instrument in the injection molding process are as follows in sequence: 260 deg.C, 270 deg.C, 280 deg.C, 290 deg.C, 295 deg.C.
As shown in fig. 2, the bonded permanent magnetic ferrite magnetic powder is cooled in an apparatus for manufacturing a multi-pole magnetic part to form an integrated multi-pole magnetic ring. The multi-pole magnetic ring comprises a first circular ring and a second circular ring which are coaxially arranged. The first ring and the second ring are connected by at least two opposite spokes. The inner diameter of the second ring is larger than the outer diameter of the first original ring, and the second ring is arranged on the outer side of the first ring. The first ring and the second ring have different heights. The spokes are distributed in a radiation mode, and the central extension lines of the spokes are converged at one point on the axis of the first circular ring. For example, two spokes are arranged at symmetrical positions on the same straight line passing through the center of the first ring and between the first ring and the second ring, thereby connecting the second ring and the second ring as a whole. For example, four spokes converge at the center of the first ring with a center extension line in the same plane, and the center extension line angle of adjacent spokes is ninety degrees. I.e. the extension of the centres of adjacent spokes are perpendicular to each other.
As shown in fig. 3, the first ring and the second ring of the sixteen polar rings have different longitudinal heights. The longitudinal height of the first ring is greater than the longitudinal height of the second ring. The longitudinal direction of the present invention refers to a normal direction perpendicular to the circular cross section of the first circular ring. Namely, the longitudinal direction is the same as the axial direction of the sixteen-pole magnetic ring. Preferably, the present invention will be described with reference to a size of a multipolar ring, taking a sixteen-pole ring formed in a sixteen-pole oriented magnetic field as an example. As shown in fig. 2. The inside diameter of the first ring is 7mm, and the outside diameter of the first ring is 10 mm. The difference between the inside diameter and the outside diameter of the first ring is 3mm, i.e. the thickness of the first ring is 3 mm. The inside diameter of the second ring is 15mm, and the outside diameter of the second ring is 17 mm. The difference between the inside diameter and the outside diameter of the second ring is 2mm, i.e. the thickness of the first ring is 2 mm. As shown in fig. 3, the second ring has a longitudinal height of 8 mm. The first ring has a longitudinal height of 1 Omm. The spoke connects the outside of first ring and the inboard of second ring, and the length of spoke is 5mm, and the width is 1 mm. The longitudinal height of the spokes is 8mm, which is the same as the longitudinal height of the second ring. The spokes are rectangular strips.
after the sixteen-pole magnetic ring is formed, the surface magnetic field parameters and the magnetic flux parameters of the sixteen-pole magnetic ring need to be detected, so that the magnetic properties of the bonded permanent magnetic ferrite magnetic powder are evaluated.
And measuring the magnetic flux parameters of the sixteen-pole magnetic ring. And arranging a sixteen-pole magnetic ring at the central position of the magnetic flux testing tool. At least two testing poles are distributed in a radiation mode by taking sixteen-pole magnetic rings as centers. The test poles are wound by insulated wires according to the right-hand spiral rule and the winding directions of the insulated wires of adjacent test poles are opposite. And sealing the magnetic flux testing tool and carrying out magnetic flux testing to obtain magnetic flux parameters of the multi-pole magnetic component.
Fig. 5 is a schematic view of a magnetic flux testing tool. As shown in fig. 5, the magnetic flux testing tool is a circular flat plate, and the thickness of the flat plate is 15 mm. The center of the circular flat plate is provided with a circular magnetic ring embedding opening which is the same as the center of the circular flat plate. Sixteen test poles are distributed in a radiation mode by taking a circular magnetic ring embedding opening as a center. Preferably, the magnetic flux test tool has the following dimensions: the diameter of the circular flat plate is 70 mm; the diameter of the circular magnetic ring insertion opening is 17.5 mm; the diameter of a peripheral circle formed by the test electrodes in radiation distribution is 28 mm; the cross-sectional width of the individual test pole was 1.5 mm.
And placing the sixteen-pole magnetic ring at the central position of the magnetic flux testing tool, namely embedding the circular magnetic ring into the opening. And testing the magnetic flux of the sixteen-pole magnetic ring by a drawing and inserting method. And winding each test pole on the magnetic flux test tool by using a 0.2mm enameled wire for 20 turns according to a right-hand spiral rule, and changing the winding direction of the copper wire to ensure that the polarities of adjacent pole heads are opposite. After the preparation, the copper wire theatre is sealed by epoxy E44 resin and 651 curing agent, and a lead is left for a magnetic flux test. The magnetic flux parameters are shown in table 2.
And measuring the surface magnetic field of the multi-pole magnetic device by using the surface magnetic field distribution system to obtain the surface magnetic field parameters of the sixteen-pole magnetic ring. The surface magnetic field parameters of the sixteen-pole magnetic ring are shown in table 2. The surface magnetic field profile is shown in fig. 6.
The process of testing the surface magnetic field distribution of the sixteen-pole magnetic ring comprises the following steps:
a. starting surface magnetic field testing software matched with the surface magnetic field testing system;
b. selecting a test tool according to the characteristics of the magnetic ring, and fixing a test sample and a test probe;
Note that: the test probe is as close to the surface of the sample as possible; but not in intimate contact;
c. The click test begins and the surface magnetic field is tested.
Comparative example
The permanent magnetic ferrite magnetic powder of No. 1, No. 2, No. 3 and No. 4 used in the embodiment is selected, and the bonded permanent magnetic ferrite magnetic powder particles treated by the mixing granulation process are molded into a test standard sample in an injection molding mode.
The process flow for testing the forming of the standard sample specifically comprises the following steps:
a. magnetic powder surface treatment
The surface treatment of the ferrite magnetic powder is specifically carried out by adopting a silane coupling agent KH-590. Preferably, 1kg of ferrite magnetic powder is weighed, and 10ml of KH-590 coupling agent is diluted to 10% of standard solution with absolute ethyl alcohol; and uniformly mixing the magnetic powder with the standard solution, and placing the mixed solution in a drying oven at 100 ℃ for drying for 2 hours for later use.
b. Mixing
Mixing the surface treated permanent magnetic ferrite magnetic powder with a binder to form bonded permanent magnetic ferrite magnetic powder. 1kg of the surface-treated permanent magnetic ferrite magnetic powder, 120g of nylon 12 and 10g of stearic acid amide lubricant are uniformly mixed in a high-speed mixer to form the bonded permanent magnetic ferrite magnetic powder.
c. Mixing and granulating
And mixing and granulating the bonded permanent magnetic ferrite magnetic powder. Preferably, a torque rheometer is selected to carry out mixing granulation on the bonded permanent magnetic ferrite magnetic powder to form bonded permanent magnetic ferrite magnetic powder particles. And in the process of mixing and granulating, recording parameters such as torque, pressure, material temperature and the like in real time.
The heating part of the torque rheometer from the feeding end to the mouth mold is divided into five sections, and the heating temperature is 200-250 ℃. Wherein, the heating temperature of five parts passing through the torque rheometer in the process of mixing and granulating the bonded permanent magnetic ferrite magnetic powder is as follows in sequence: 210 deg.C, 240 deg.C, 220 deg.C.
d. Melt index test
After the bonded permanent magnetic ferrite magnetic powder is subjected to a mixing granulation process to form bonded permanent magnetic ferrite magnetic powder particles, a melt index value of the extruded granulation is tested by using a melt index instrument. Preferably, the test temperature is 270 ℃ and the load is 5 kg. The melt index is shown in Table 2.
e. Injection molding method for forming standard sample for magnetic performance test
And forming a magnetic performance test standard sample by using the bonded permanent magnetic ferrite magnetic powder particles in an injection molding mode. The injection temperature of the bonded permanent magnetic ferrite magnetic powder particles is 250-300 ℃. Wherein, the heating temperature of five parts of bonding permanent magnetic ferrite magnetic powder granule process injection instrument at injection moulding's in-process is in proper order: 260 deg.C, 270 deg.C, 280 deg.C, 290 deg.C, 295 deg.C.
The standard sample is a bipolar cylinder. Standard sample size: phi 20mm multiplied by 10mm, an orientation magnetic field 9000Gs, four performance parameters: remanence (Br) parameter, magnetic induction coercivity (Hcb) parameter, intrinsic coercivity (Hcj) parameter, and maximum magnetic energy product (BH) max parameter. The four parameters are shown in table 2.
table 2: list of parameters for example 1 and comparative examples
The magnetic characteristic parameters of the examples and those of the comparative examples were compared, and the evaluation results of the examples and those of the comparative examples were greatly different.
If the four kinds of magnetic powder are tested by adopting a comparative example, the residual magnetism sequence is 2# > 1# > 3# > 4 #; the magnetic properties of # 2 are better.
if the four kinds of magnetic powder are tested by the embodiment method, the surface magnetic field sequence is 4# > 2# > 3# > 1#, wherein the surface fields of 1#, 2# and 3# have small difference, the surface magnetic field of 4# is about 4% larger than that of 1# and the magnetic property of 4# is better.
the comparative examples passed four performance parameters: and evaluating the magnetic properties of the bonded permanent magnetic ferrite magnetic powder by using a remanence (Br) parameter, a magnetic induction coercive force (Hcb) parameter, an intrinsic coercive force (Hcj) parameter and a maximum magnetic energy product (BH) max parameter. Although the four parameters have a certain correlation influence relationship with the surface magnetic field of the magnetic device, the influence factors of the surface magnetic field of the magnetic device are numerous, an accurate and strict corresponding relationship does not exist, even the difference between the four performance indexes of the magnetic powder injection standard sample is not large sometimes, but the difference between the surface field and the magnetic flux of the magnetic device is large finally, so that the evaluation result of the comparative example has limitation.
Under the condition of the same detection condition, the higher the magnetic flux and the surface magnetic field of the magnetic device are, the better the magnetic property performance of the magnetic powder is. The invention can more directly and accurately represent the magnetic property of the magnetic powder through the magnetic flux and the surface magnetic field parameters.
Example 2
This embodiment is a further improvement and explanation of the apparatus for manufacturing a multi-pole magnetic member of embodiment 1. The same contents as those of embodiment 1 will not be described again.
The apparatus for manufacturing a multi-pole magnetic component of the present invention comprises at least two oriented magnets distributed on a hollow annular base formed of a non-magnetically conductive material. At least two orientation magnets are used to fixedly form a multi-pole magnetic feature in a magnetic field in a multi-pole magnetic component within the annular base on the annular base. At least two screens for fixing the orientation magnetic field in a detachable mode are arranged on the outer side of the annular base. The annular base comprises a circular ring base, a rectangular ring base or a regular polygonal ring base.
FIG. 4 is a preferred embodiment of the apparatus for fabricating a multi-pole magnetic component of the present invention. As shown in fig. 4, the magnetic conductive material of the oriented magnet 1 is a high-performance rare earth permanent magnetic material. The annular base is a circular ring base 3. The non-magnetic conductive material of the annular ring base 3 includes cemented carbide and austenitic stainless steel materials. The multi-pole magnetic component is a multi-pole magnetic ring 2. A multi-polar magnetic ring 2 is formed in an injection mould in an annular base 3.
According to a preferred embodiment, the orienting magnets are uniformly radially distributed about the annular base with adjacent poles of opposite polarity. The multi-pole magnetic ring is formed by injecting the caking permanent magnetic ferrite magnetic powder in an injection mould in the annular base. The injection hole is provided on the injection mold.
the caking permanent magnetic ferrite magnetic powder is formed into a multi-pole magnetic ring after being molded and cooled in an injection mold. The oriented magnetic field formed by the plurality of oriented magnets defines the number of magnetic poles of the multi-pole magnetic ring. For example, if the number of the alignment magnets is eight, the eight alignment magnets form an alignment magnetic field of eight magnetic poles. The caking permanent magnetic ferrite magnetic ring formed in the orientation magnetic field of eight magnetic poles is an eight-pole magnetic ring. If the number of the oriented magnets is twelve, the twelve oriented magnets form an oriented magnetic field of twelve magnetic poles. The bonding permanent magnetic ferrite magnetic ring formed in the orientation magnetic field of twelve magnetic poles is a twelve-pole magnetic ring. Preferably, the magnetic conductive material of the oriented magnet 1 is a high-performance rare earth permanent magnetic material. The non-magnetic conductive material of the annular base comprises hard alloy and austenitic stainless steel materials. The multi-pole magnetic ring 2 is formed in the annular base 3.
The invention forms a sixteen-pole magnetic ring in a circular ring base distributed with sixteen oriented magnets by bonding permanent magnetic ferrite magnetic powder. As shown in fig. 4, the apparatus for manufacturing a sixteen-pole magnetic device includes sixteen oriented magnets, a non-magnetic conductive annular ring base, and an injection mold. The outside of the circular ring base is provided with at least two clamping positions which are uniformly distributed and used for fixing the orientation magnet. Sixteen clamping positions which are uniformly distributed are arranged on the outer side of the circular ring base. Preferably, the clamping positions matched with the orientation magnets are uniformly distributed on the outer side of the circular ring base, so that the number of the orientation magnets can be conveniently installed as required.
The oriented magnet made of magnetic conductive material is a cube with a rectangular cross section. The two ends of the oriented magnet have different polarities, one end is an S pole, and the other end is an N pole. Sixteen oriented magnets are radially distributed around the non-magnetic circular ring base as the center. One end of the orientation magnet is in contact with the circular ring base, and the extension line of the center of the orientation magnet passes through the center of the circular ring base. The adjacent orientation magnets have different polarities at one end close to the circular ring base and are not in contact with each other. That is, the S pole and the N pole of the adjacently oriented magnets are adjacent and spaced apart from each other by a certain distance. Preferably, the oriented magnet is a rectangular parallelepiped. The cross section of the oriented magnet is rectangular. The rectangle is 20mm in length and 2mm in width. The height of the oriented magnet was 15 mm. The circular ring base is an annular base which is made of non-magnetic conducting materials and has a certain thickness. The annular ring base has an inside radius and an outside radius. The difference between the inside radius and the outside radius of the ring is 2 mm. I.e. the thickness of the circular ring base is 2 mm.
Preferably, the orientation magnet 1 further includes a cylindrical magnet and a polygonal bar magnet. The orientation magnet 1 may be a solid magnet or a hollow magnet having a cavity inside. The cylindrical orientation magnet 1 may be a constant diameter magnet or a variable diameter magnet. The diameter-variable magnet is a magnet with two ends of different diameters and gradually changed.
According to a preferred embodiment, the orienting magnets are non-uniformly radially distributed about the base of the annular ring. I.e. the spacing of adjacent oriented magnets is not equal. For example, sixteen oriented magnets are numbered 1, 2, 3 … … 14, 15, 16 in sequence. The N-pole of the orientation magnet No. 1 is in contact with the annular base. The S-pole of the orientation magnet No. 2 is in contact with the annular base. The N-pole of the orienting magnet No. 3 is in contact with the annular base. The S-pole of the orientation magnet No. 4 is in contact with the annular base. … … the N pole of the orientation magnet number 15 is in contact with the annular base. The S-pole of the orienting magnet 16 is in contact with the annular base. The contact ends of adjacent oriented magnets and the annular base are different from each other. The distances between the oriented magnets are regularly distributed. The magnetic pole distances between the oriented magnets are distributed in a regular pattern of ABAB. For example, the distance between the N pole of the alignment magnet No. 1 and the S pole of the alignment magnet No. 2 is a, and the distance between the S pole of the alignment magnet No. 2 and the N pole of the alignment magnet No. 3 is B. The distance between the N-pole of the alignment magnet No. 3 and the S-pole of the alignment magnet No. 4 is a, and the distance between the S-pole of the alignment magnet No. 4 and the N-pole of the alignment magnet No. 5 is B. By analogy, the distances between the adjacent oriented magnets are distributed in a and B staggered mode.
Preferably, the magnetic pole distances between the oriented magnets are distributed in the regular pattern of AABB. For example, the distance between the N pole of the alignment magnet No. 1 and the S pole of the alignment magnet No. 2 is a, and the distance between the S pole of the alignment magnet No. 2 and the N pole of the alignment magnet No. 3 is a. The distance between the N pole of the alignment magnet No. 3 and the S pole of the alignment magnet No. 4 is B, and the distance between the S pole of the alignment magnet No. 4 and the N pole of the alignment magnet No. 5 is B. The distance between the N pole of the alignment magnet No. 5 and the S pole of the alignment magnet No. 6 is a, and the distance between the S pole of the alignment magnet No. 6 and the N pole of the alignment magnet No. 7 is a. By analogy, the distances between adjacent oriented magnets are staggered AA and BB.
preferably, the magnetic pole distances between the oriented magnets are regularly distributed in the AAAABBBB.
Preferably, the magnetic pole distances among the oriented magnets can be distributed according to the ABCBC rule according to different numbers of the oriented magnets. For example, an apparatus for manufacturing a nine-pole magnetic ring includes nine oriented magnets radially distributed about an annular base. The magnetic pole distances between the nine oriented magnets are distributed abcabcabcabc.
The oriented magnetic field formed by the regularly distributed oriented magnets is uniform. The multi-pole magnetic ring formed by injection in the oriented magnetic field has uniform magnetism. And the magnetic characteristics of the caking permanent magnetic ferrite magnetic powder are represented by testing the magnetic flux and the surface field of the multi-pole magnetic ring.
Example 3
The present embodiment further improves and explains the multi-pole magnetic component in the foregoing embodiments, and the same contents are not described again.
A multi-pole magnetic part is molded from bonded permanent magnetic ferrite powder in a multi-pole injection mold for manufacturing the multi-pole magnetic part. The magnetic properties of the bonded permanent magnetic ferrite magnetic powder were evaluated by measuring the magnetic properties of the multi-pole magnetic part. The integrally formed multi-pole magnetic component comprises a first ring, a second ring and at least two spokes, wherein the first ring is coaxially arranged, the inner diameter of the second ring is larger than the outer diameter of the first ring, the spokes are connected with the first ring and the second ring, and the height of the first ring is larger than that of the second ring.
the spokes are distributed in a radiation mode, and the central extension lines of the spokes are converged at one point on the axis of the first circular ring. As shown in fig. 2, four spokes are disposed between the first magnetic ring and the second magnetic ring, so as to increase the stability between the first circular ring and the second circular ring. Preferably, four spokes converge to one point on the axis between the first ring and the second ring which are coaxially arranged in a way that adjacent center extension lines are crossed to form a 90-degree angle. The arrangement of the four spokes avoids the deformation of the first ring due to unbalanced stress in the use process, increases the stability between the first ring and the second ring, ensures that the multi-pole magnetic ring is not easy to deform as a whole, and prolongs the service life. Meanwhile, at least one spoke has a supporting function on the second ring in the using process, and deformation of the second ring is avoided. Compared with a multi-pole magnetic ring formed by a single circular ring, the multi-pole magnetic ring is higher in stability and is less prone to deformation.
Preferably, the spokes are distributed in a radial manner, and the central extension lines of the spokes do not converge on the axle center of the first ring. The central extension lines of the spokes do not converge at the axle center of the first ring and converge at other positions. The spokes arranged between the first ring and the second ring also have the functions of isolation and support.
Preferably, the spokes are evenly distributed between the first ring and the second ring in such a way that the central extension line and the tangent of the outer diameter of the first ring form the same angle. For example, at least two spokes are distributed between the first ring and the second ring in a manner of forming an angle of 60 degrees with the tangent of the first ring, and the first ring and the second ring are connected into a whole.
Preferably, the spokes comprise circular, rectangular and/or polygonal bars. The circular bars also comprise isodiametric bars and variable diametric bars. The equal diameter strip means that the diameter of the cylinder between the two ends of the circular strip is always equal. The diameter-variable strip means that the diameters of the cylinders between the two ends of the circular strip are not equal, and the diameters between the two ends are gradually changed.
preferably, the cross sections of the first circular ring and the second circular ring of the multi-pole magnetic ring are planar circular rings. Or the annular cross sections of the first ring and the second ring of the multi-pole magnetic ring are arc-shaped surfaces with radians. Or the annular cross sections of the first ring and the second ring of the multi-pole magnetic ring are polygonal annular surfaces with ridge lines.
As shown in FIG. 2, the inner diameter of the first ring of the sixteen-pole magnetic ring is 7mm, and the outer diameter of the first ring is 10 mm. The difference between the inside diameter and the outside diameter of the first ring is 3mm, i.e. the thickness of the first ring is 3 mm. The inside diameter of the second ring is 15mm, and the outside diameter of the second ring is 17 mm. The difference between the inside diameter and the outside diameter of the second ring is 2mm, i.e. the thickness of the first ring is 2 mm. As shown in fig. 3, the second ring has a longitudinal height of 8 mm. The first ring has a longitudinal height of 10 mm. The spoke connects the outside of first ring and the inboard of second ring, and the length of spoke is 5mm, and the width is 1 mm. The longitudinal height of the spokes is 8mm, which is the same as the longitudinal height of the second ring. The spokes are rectangular strips.
The size of the multi-pole magnetic member of the present invention is not limited to the above size. The multi-pole magnetic ring has various sizes, and can be expanded or reduced in an equal proportion according to requirements. Moreover, the invention can adjust the injection mould according to the actual requirement, thereby adjusting the distance between the first circular ring and the second circular ring.
It should be noted that the above-mentioned embodiments are exemplary, and that those skilled in the art, having benefit of the present disclosure, may devise various arrangements that are within the scope of the present disclosure and that fall within the scope of the invention. It should be understood by those skilled in the art that the present specification and figures are illustrative only and are not limiting upon the claims. The scope of the invention is defined by the claims and their equivalents.
Claims (6)
1. A method for evaluating the magnetic property of bonded permanent magnetic ferrite magnetic powder is characterized by comprising the following steps:
The bonded permanent magnetic ferrite magnetic powder is molded into a multi-pole magnetic part in an apparatus for manufacturing the multi-pole magnetic part,
Evaluating the magnetic properties of the bonded permanent magnetic ferrite magnetic powder by measuring the surface field and the magnetic flux of the multi-pole magnetic part; wherein the content of the first and second substances,
The device for manufacturing the multi-pole magnetic component comprises at least two orientation magnets distributed on an annular base formed by non-magnetic-conductive materials, wherein the at least two orientation magnets are used for enabling the multi-pole magnetic component in the annular base to form multi-pole magnetic characteristics in a magnetic field in a fixed mode on the annular base, and at least two clamping positions used for fixing the orientation magnets in a detachable mode are arranged on the outer side of the annular base;
The multipole magnetic component is integrally formed and comprises a first circular ring, a second circular ring and at least two spokes, wherein the first circular ring and the second circular ring are coaxially arranged, the inner diameter of the second circular ring is larger than the outer diameter of the first circular ring, the spokes are connected with the first circular ring and the second circular ring, and the height of the first circular ring is larger than that of the second circular ring.
2. the method for evaluating the magnetic properties of a bonded permanent magnetic ferrite magnetic powder according to claim 1, wherein the bonded permanent magnetic ferrite magnetic powder having uniaxial anisotropy is injected in a molten state into an injection mold in the annular base and is rotationally molded under the action of a magnetic field into a multi-pole magnetic part having multi-pole magnetic properties.
3. the method for evaluating the magnetic properties of a bonded permanent magnetic ferrite magnetic powder according to claim 2, wherein the melting temperature of the bonded permanent magnetic ferrite magnetic powder is 250 ℃ to 300 ℃, wherein the heating temperatures of the bonded permanent magnetic ferrite magnetic powder passing through five parts of an injection instrument during the injection molding are sequentially as follows: 260 deg.C, 270 deg.C, 280 deg.C, 290 deg.C, 300 deg.C.
4. The multi-pole magnetic part used in the evaluation method of magnetic properties of a bonded permanent magnetic ferrite magnetic powder according to one of the preceding claims, wherein the multi-pole magnetic part is molded from a bonded permanent magnetic ferrite magnetic powder in an injection mold for manufacturing a multi-pole magnetic part, and the magnetic properties of the bonded permanent magnetic ferrite magnetic powder are evaluated by measuring a surface field and a magnetic flux of the multi-pole magnetic part; wherein the content of the first and second substances,
The multipole magnetic component is integrally formed and comprises a first circular ring, a second circular ring and at least two spokes, wherein the first circular ring and the second circular ring are coaxially arranged, the inner diameter of the second circular ring is larger than the outer diameter of the first circular ring, the spokes are connected with the first circular ring and the second circular ring, and the height of the first circular ring is larger than that of the second circular ring.
5. the multipole magnetic component of claim 4 wherein the spokes are radially spaced and the central extensions of the spokes converge at a point on the axis of the first ring; or
The spokes are distributed in a radiation manner, and the central extension lines of the spokes do not converge on the axis of the first ring; or
The spokes are uniformly distributed between the first circular ring and the second circular ring in a mode that a central extension line and a tangent of the outer diameter of the first circular ring form the same angle.
6. A multipole magnetic component according to claim 4 or 5, wherein the first and second rings of the multipole magnetic component are planar circular rings in transverse cross-section, the spokes comprising circular, rectangular and/or polygonal bars, the circular bars further comprising constant and varying diameter bars.
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