CN213519585U

CN213519585U - Pole anisotropic orientation magnet, mold for manufacturing same, ring magnet, motor rotor, and motor

Info

Publication number: CN213519585U
Application number: CN202021549097.9U
Authority: CN
Inventors: 史丙强; 张玉孟; 薛令文; 魏蕊
Original assignee: Yantai Zhenghai Magnetic Material Co Ltd
Current assignee: Yantai Zhenghai Magnetic Material Co Ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2021-06-22
Anticipated expiration: 2030-07-30

Abstract

The utility model discloses a utmost point heteropolarity orientation magnetite, mould, ring shape magnetite, electric motor rotor and the motor of its manufacturing usefulness. A mold for producing a magnet having a polar anisotropic orientation, comprising: the female die comprises a first alloy area and a second alloy area, and the magnetic conductivity of the second alloy is stronger than that of the first alloy; and the cavity is in an arc shape and is positioned in the first alloy area. By using the mold, a magnet arc having the same orientation as one or half of the pole of the anisotropic pole ring magnet can be manufactured, and a magnet arc having an ideal anisotropic pole orientation can be obtained. The circular arc magnets can be spliced into a circular ring magnet, and the surface magnetic flux density of the circular ring magnet is distributed into a sine waveform. When such a ring magnet is used as a rotor, a motor with low cogging torque can be obtained.

Description

Pole anisotropic orientation magnet, mold for manufacturing same, ring magnet, motor rotor, and motor

Technical Field

The utility model belongs to neodymium iron boron system sintered magnet field relates to neodymium iron boron system sintered magnet's manufacturing method, in particular to utmost point anisotropy orientation magnetite, mould, ring shape magnetite, electric motor rotor and the motor of its manufacturing usefulness.

Background

Since the discovery, the neodymium iron boron permanent magnet material is widely applied to the fields of communication, medical treatment, automobiles, electronics, aviation and the like with excellent magnetic performance and high cost performance. Neodymium iron boron materials are classified into axial orientation magnets, radial orientation magnets (or called anisotropic magnets) and the like according to different orientations. Compared with the axial orientation magnet and the radiation orientation magnet, the surface magnetic flux density of the heteropolarity magnet has sine wave shape, so the volume of the motor can be reduced, and the cogging torque of the motor can be reduced.

Patent document 1 (japanese patent publication No. 6-024174) discloses a method for manufacturing a polar anisotropic ring magnet. The magnets are oriented in multiple stages by applying N, S pole-interleaved magnetic fields to the magnetic ring circumferentially during the profiling process, as shown in fig. 1. And sintering to obtain the heteropolarity magnet. In the sintering process of the preparation method, the arrangement of the crystal grains can automatically change due to the magnetic field orientation, so that the crystal magnetic anisotropy axis of the crystal grains is arranged along the bending of the magnetic force line, the shrinkage rate of the annular blank at the magnetic pole orientation position is higher than that at the magnetic pole connection position, and the outline of the blank is changed into a polygon instead of a circle, as shown in fig. 2.

Patent document 2(CN104465061B) discloses a method for solving the contour distortion of a polar anisotropic circular ring blank. The annular die cavity of the die is designed to have a wider space corresponding to the alignment position of the magnetic poles and a narrower space corresponding to the junction position of the magnetic poles, so that the blank can approach to a true circle after the subsequent sintering is finished. However, the method still causes the cracking phenomenon of the product due to the large difference of the shrinkage rate and the thermal expansion coefficient of the product in the radial direction and the tangential direction during the sintering process.

In order to solve the problems of deformation and cracking of the anisotropic pole ring magnet, a rotary machine is generally configured by manufacturing a circular arc magnet and then attaching the circular arc magnet to a yoke to form a ring. In order to achieve the effect that the magnetic flux density on the surface of the heteropolar ring magnet has a sine wave, the entrance and the exit of the magnetic force lines inside the circular-arc magnet need to have different angles relative to the same reference surface. Further, the arc-shaped magnet cannot be produced using the mold and the method of patent document 1. In the mold disclosed in patent document 1, it is very difficult to adjust the arrangement and strength of the magnetic field generating coils, and it is difficult to obtain a pole anisotropy circular arc magnet having an ideal orientation.

Patent document 3(CN108352768A) discloses a magnet of circular arc shape having a polar anisotropic orientation, but does not disclose a specific manufacturing method for manufacturing a magnet of circular arc shape having a polar anisotropic orientation.

Patent document 4(CN103299381A) discloses a method for manufacturing an arc-shaped magnet having a polar anisotropic orientation. The magnetic conduction blocks are arranged at different positions in the parallel magnetic field, so that the direction of the magnetic field is changed, and the effect of changing the magnetic force line in the magnet is achieved. However, the method disclosed in this patent document differs from the ideal polar anisotropic orientation, and a plurality of circular magnets are joined into a ring, and the ring has a low surface magnetic flux density, and the cogging torque cannot be reduced significantly.

Therefore, it is an urgent technical problem to obtain an arc magnet with ideal anisotropic magnet orientation to significantly reduce the cogging torque of the motor.

SUMMERY OF THE UTILITY MODEL

In order to improve the technical problem, the utility model provides a preparation utmost point anisotropic oriented magnetite's mould, the mould includes:

the female die comprises a first alloy area and a second alloy area, and the magnetic conductivity of the second alloy is stronger than that of the first alloy;

and the cavity is in an arc shape and is positioned in the first alloy area.

According to the utility model discloses an embodiment, the bed die is the cuboid, and first alloy district is the type of falling Y in the cuboid, and the second alloy is filled in the both sides of the type of falling Y sideline. Preferably, the filling is a symmetrical filling.

According to the utility model discloses an embodiment, the type of falling Y sideline includes two oblique sidelines and two horizontal sidelines. Preferably, the two diagonal lines and the two horizontal lines are axisymmetric with respect to a horizontal line.

According to an embodiment of the present invention, the first alloy zone comprises zone a, zone B and zone C, wherein zone a is a rectangular zone enclosed by two intersections of the hypotenuse line and the side line of the female mold, and two vertices close to the female mold; the region B is a trapezoidal region formed by two intersection points of the inclined sideline and the horizontal sideline and two intersection points of the inclined sideline and the female mould sideline; the region C is a rectangular region formed by two intersection points of the inclined sideline and the horizontal sideline and two intersection points of the horizontal sideline and the female die sideline.

According to the utility model discloses an embodiment, the cavity is in regional B completely to guarantee that there is sufficient magnetic line of force to pass through circular-arc cavity.

According to the utility model discloses an embodiment, second alloy district is including regional D and regional E, regional D and regional E are by nodical, the nodical of hypotenuse line and horizontal sideline, with the nodical of the horizontal sideline that the hypotenuse line intersects and the bed die sideline and the region that encloses with this horizontal sideline apart from the nearest bed die summit of this horizontal sideline. That is, the region D and the region E are axisymmetric with respect to the horizontal line.

According to the utility model discloses an embodiment, first alloy is non-magnetic conduction or the weaker alloy of magnetic conductivity, and preferably non-magnetic conduction alloy can form required magnetic line of force trend better. For example, the non-magnetic conductive alloy is preferably 304 stainless steel, 70MN carbon steel or G60 steel material.

According to an embodiment of the invention, the second alloy is an alloy with strong magnetic permeability; such as 45# steel or chromium 12 steel.

According to the utility model discloses an embodiment, the cross section of cavity is the closed arc surface that inner arc, outer arc and two lateral walls constitute. The inner arc refers to an arc close to the center of a circle, and the outer arc refers to an arc far away from the center of a circle. The height, thickness, etc. of the chamber can be adjusted by one skilled in the art as required by the product specification.

According to an embodiment of the invention, the chamber is located completely within the region B.

According to an embodiment of the invention, the height of the first alloy zone, the second alloy zone and the chamber is equal.

According to the utility model discloses an embodiment, the mould still includes the N utmost point and the S utmost point, the N utmost point and the S utmost point include the utmost point head respectively and twine magnetic field coil on the utmost point head. Preferably, the N pole and the S pole are respectively disposed at both sides of the female mold so that the female mold is placed in a parallel magnetic field formed by a magnetic field coil. Preferably, the female die has a side surface area that is more than 70%, such as more than 75%, and such as more than 80% of the area of the N or S pole.

According to the utility model discloses an embodiment, parallel magnetic field passes the cavity, the entry of the inside magnetic line of force of cavity and the export homogeneous phase of magnetic line of force are for seal the circular arc and personally submit certain angle. Preferably, the angle difference between the outlet of the magnetic field lines and the inlet thereof is less than 70 °, for example 5-60 °, exemplary 10 °, 20 °, 30 °, 40 °, 50 °, 60 °.

Preferably, the distance between the two straight sides of the high magnetic permeability alloy and the non-magnetic/low magnetic permeability alloy is greater than half of the length of the arc-shaped chamber in the magnetic field direction, and the length in the magnetic field direction refers to the projection length of the arc-shaped chamber in the magnetic field direction.

The utility model discloses still provide a manufacturing approach of the magnetite of utmost point anisotropic orientation, including following step:

1) preparing or preparing magnetic powder of neodymium-iron-boron sintered magnet;

2) loading the magnetic powder into the die, orienting in a parallel magnetic field and pressing for forming to obtain a pressed blank;

3) and sintering and tempering the pressed compact, and cooling to obtain the magnet with the polar anisotropic orientation.

According to an embodiment of the present invention, in step 1), the magnetic powder comprises R-Fe-B-M alloy jet milled powder and lubricant, and the mass ratio of the lubricant to the R-Fe-B-M alloy jet milled powder is 0.05-1: 100, preferably 0.1-0.5:100, exemplarily 0.1:100, 0.2:100, 0.3:100, 0.4:100, 0.5: 100. Wherein the lubricant may be selected from lubricants known in the art.

According to an embodiment of the present invention, in the R-Fe-B-M alloy jet mill, R represents at least one element of rare earth elements, and M represents at least one or more of Co, Ga, Cu, Al, Zr, and Ti.

Preferably, R is selected from at least one of Nd, Pr, Dy, Tb, La, Ce, Pr, Pm, Eu, Sc, Gd, Ho, Er, Tm, Yb, Lu and Y, preferably at least one of Nd, Pr and Dy.

Preferably, the amount of R is 26 wt% < R <35 wt%, such as 28 wt% ≦ R ≦ 33 wt%, exemplary 28 wt%, 30 wt%, 30.5 wt%, 31 wt%, 33 wt%.

Preferably, the B is present in an amount of 0.5 to 1.5 wt%, such as 0.8 to 1.3 wt%, exemplary 0.9 wt%, 0.98 wt%, 1.0 wt%, 1.1 wt%, 1.3 wt%.

Preferably, said M comprises Co, Ga and Cu, and optionally Al, Zr, Ti, or not. For example, the content of Co is 0.5 to 3.0 wt%, the content of Ga is 0.05 to 0.4 wt%, the content of Cu is 0.05 to 0.5 wt%, the content of Al is 0 to 1.5 wt%, and the content of Zr or Ti is 0 to 0.3 wt%. Illustratively, M comprises 1.0 wt% Co, 0.10 wt% Ga, 0.15 wt% Cu, 0.5 wt% Al, 0.12 wt% Zr.

Preferably, the R-Fe-B-M alloy jet mill powder is composed of iron and inevitable impurities, except R, B and M.

According to an embodiment of the invention, in step (1), the R-Fe-B-M alloy jet mill has an average particle size of 1 to 6 μ M, such as 2 to 4 μ M, exemplarily 2 μ M, 2.5 μ M, 3 μ M, 3.1 μ M, 3.5 μ M, 4 μ M.

According to the embodiment of the present invention, in the step (1), the preparation process of the R-Fe-B-M alloy jet mill powder comprises: r, M metal and ferroboron are mixed, melted, poured and quenched to obtain alloy; and crushing the alloy, and carrying out jet milling to obtain the R-Fe-B-M alloy jet milled powder.

For example, the melting may be by means known in the art, preferably high frequency melting in an inert atmosphere (e.g., argon or nitrogen).

For example, the casting and quenching operations may be those known in the art, and preferably the molten melt is cast onto a chill roll to obtain an alloy.

For example, the pulverization may be a pulverization method known in the art, and is preferably a hydrogenation pulverization.

According to an embodiment of the present invention, in step (1), the magnetic powder is mixed uniformly by the airflow milled powder of the R-Fe-B-M alloy and the lubricant according to the above ratio, for example, the mixing time is 0.1 to 3 hours, preferably 0.5 to 2.5 hours, and exemplary is 0.5 hour, 1 hour, 1.5 hour, 2 hours, 2.5 hours, and 3 hours.

According to the embodiment of the present invention, in the step (2), the density of the green compact is not less than 3.5g/cm³E.g. a density of 4g/cm or more³。

According to an embodiment of the present invention, in step (3), the sintering temperature is 1000-. Further, the sintering time is 4-8h, such as 5-7h, exemplary 5h, 6h, 7 h.

According to an embodiment of the present invention, in step (3), the tempering treatment comprises at least one stage of tempering treatment, preferably two stages of tempering treatment.

For example, the temperature of the first stage tempering treatment is 800-. Further, the first tempering treatment time is 1-5h, such as 2-4h, and is exemplified by 2h, 3h, and 4 h.

For example, the temperature of the second tempering treatment is 450-. Further, the time of the second tempering treatment is 3-8h, such as 4-7h, and exemplary 4h, 5h, 6h, 7 h.

According to an embodiment of the present invention, in the step (3), the cooling is natural cooling.

According to an embodiment of the present invention, the method further optionally includes a step (4) of subjecting the magnet having the anisotropic orientation to grain boundary diffusion treatment.

According to the embodiment of the present invention, in the step (4), the grain boundary diffusion treatment may be performed by a coating method, a thermal spraying method, an evaporation method, a dipping method, or the like, preferably by a thermal spraying method.

According to an embodiment of the present invention, a method of manufacturing a magnet having a polar anisotropic orientation includes the steps of:

1) preparing or preparing magnetic powder of neodymium-iron-boron system sintered magnet: adding a lubricant accounting for 0.1-0.5% of the mass of the R-Fe-B-M alloy airflow milled powder into the R-Fe-B-M alloy airflow milled powder, and mixing for 0.1-3 h;

wherein in the R-Fe-B-M alloy, R represents at least one element of rare earth elements, the content of R is 26 wt% to less than R <35 wt%, the content of B is 0.8 wt% to 1.3 wt%, M comprises Co, Ga and Cu, and optionally comprises or does not comprise Al, Zr and Ti; 0.5-3.0 wt% of Co, 0.05-0.4 wt% of Ga, 0.05-0.5 wt% of Cu, 0-1.5 wt% of Al, 00.3 wt% of Zr or Ti, and the balance of Fe and inevitable impurities;

2) loading the magnetic powder into the die, orienting in a parallel magnetic field and compressing and molding to obtain a green compact;

The utility model also provides a magnetic stone of utmost point anisotropic orientation, the entry of the magnetic line of force of magnetic stone has the angular difference with the export of magnetic line of force. Preferably, the angle difference is <70 °, preferably 5-60 °.

Preferably, the magnet having a polar anisotropic orientation is produced by the above method.

According to an embodiment of the present invention, the shape of the magnet having a polar anisotropic orientation is circular arc, preferably the same as the shape of the cavity.

The utility model also provides a circle ring magnet, circle ring magnet by the magnetite combination of utmost point anisotropic orientation forms.

The utility model discloses still provide a preparation method of circle ring magnet, including following step: and combining the magnets with the polar anisotropic orientation into a ring-shaped magnet.

The utility model discloses still provide the magnetite of utmost point anisotropic orientation and/or the application of ring shape magnetite in reducing motor tooth's socket torque. For example as a rotor of an electrical machine.

The utility model also provides an electric motor rotor, its contain the magnetite of utmost point anisotropic orientation and/or ring shape magnetite.

The utility model also provides a motor, the motor contains above-mentioned electric motor rotor.

The utility model has the advantages that:

the utility model provides a mould for preparing circular-arc magnetite of utmost point anisotropy orientation utilizes the shape of bed die and cavity and the magnetic conductivity difference of alloy, makes the entry and the export of the magnetic line of force of the magnetite in the cavity demonstrate different angles for the cavity cross-section. By using the mold, a magnet arc having the same orientation as one or half of the pole of the anisotropic pole ring magnet can be manufactured, and a magnet arc having an ideal anisotropic pole orientation can be obtained. The circular arc magnets can be spliced into a circular ring magnet, and the surface magnetic flux density of the circular ring magnet is distributed into a sine waveform. When such a ring magnet is used as a rotor, a motor with low cogging torque can be obtained.

Drawings

Fig. 1 shows a method for manufacturing a heteropolar ring magnet and a press molding process disclosed in patent document 1.

Fig. 2 shows a polar anisotropic ring magnet disclosed in patent document 1, in which the number of orientations is eight.

FIG. 3 is a perspective view of an arc-shaped magnet according to example 3.

FIG. 4 is a sectional view of the arcuate magnet in example 3 in the orientation direction.

Fig. 5 is a top view of the mold structure of example 1.

Fig. 6 is a cross-sectional view of the mold of example 1 taken along a plane parallel to the central axis of the two pole heads.

Fig. 7 is a top view of the mold structure of example 2.

Fig. 8 is a schematic sectional shape of the chamber of example 1.

Fig. 9 is a schematic view showing the magnetic field condition when a parallel magnetic field is applied to the mold shown in example 1.

Fig. 10 is a schematic view showing the magnetic field condition when a parallel magnetic field is applied to the mold shown in example 2.

FIG. 11 is a schematic representation of the positional relationship of the bevel edge of the contact of the first alloy region and the second alloy region with the cavity in the mold of example 1.

Fig. 12 is another exemplary illustration of the positional relationship of the bevel edge of the contacting first alloy region and second alloy region with the cavity in the mold.

Fig. 13 is a schematic view of the structure of the mold used in comparative example 1.

FIG. 14 is a graph showing the surface magnetic flux density of the sintered magnets of example 4, example 5, and comparative example 1 after assembly.

Fig. 15 is a schematic view showing calculation of the entrance and exit angles of the magnetic flux lines in example 1.

FIG. 16 is a schematic view of a magnet having a polar anisotropic ring.

Reference numerals:

10-circular arc magnet, 11-first side wall, 12-second side wall, 13-outer arc, 14-inner arc, 20-female mold, 21-first magnetic field coil, 22-second magnetic field coil, 23-pole head, 24-first alloy region, 25-second alloy region, and 26-chamber.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to the following embodiments. It is to be understood that the following examples are illustrative only and are not to be construed as limiting the scope of the invention. All the technologies realized based on the above mentioned contents of the present invention are covered in the protection scope of the present invention.

Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

Example 1

As shown in fig. 5, the mold for producing a magnet having a circular arc shape with a polar anisotropic orientation includes:

the female die 20 comprises a first alloy area 24 and a second alloy area 25, and the magnetic permeability of the second alloy is stronger than that of the first alloy; the female die 20 is a rectangular body, the first alloy zone 24 is inverted Y-shaped in the rectangular body, and the second alloy is symmetrically filled on two sides of the side line of the inverted Y-shaped. The inverted Y-shaped edge line comprises two oblique edge lines and two horizontal edge lines, the horizontal line is used as an axis, and the two oblique edge lines and the two horizontal edge lines are in axial symmetry.

And a cavity 26, wherein the cavity 26 is in an arc shape and is positioned in the first alloy zone 24.

The first alloy zone 24 comprises a zone a, a zone B and a zone C, wherein the zone a is a rectangular zone surrounded by two intersections of the hypotenuse line and the edge line of the female mold and two vertices adjacent to the female mold; the region B is a trapezoidal region which is formed by two intersection points of the inclined sideline and the horizontal sideline and two intersection points of the inclined sideline and the female mould sideline; the region C is a rectangular region formed by two intersection points of the inclined sideline and the horizontal sideline and two intersection points of the horizontal sideline and the female die sideline.

The chamber 26 is completely within the region B, thereby ensuring that sufficient magnetic lines of force pass through the arcuate chamber. Figure 11 is a schematic representation of the positional relationship of the hypotenuse of the contact of the first alloy region 24 and the second alloy region 25 to the chamber 26. It can be seen that the length of the hypotenuse of the first alloy region 24 and the second alloy region 25 perpendicular to the parallel magnetic field exceeds that of the chamber 26. Thus, the magnetic force lines in the arc-shaped magnet can meet the requirement of polarity anisotropy.

The second alloy zone 25 includes a zone D and a zone E, both the zone D and the zone E are surrounded by an intersection point of the oblique edge line and the female die edge line, an intersection point of the oblique edge line and the horizontal edge line, an intersection point of the horizontal edge line intersecting the oblique edge line and the female die edge line, and a female die vertex closest to the horizontal edge line. That is, the region D and the region E are axisymmetric with respect to the horizontal line.

The first alloy is non-magnetic conductive alloy, and can better form the required magnetic line trend. For example, the non-magnetic conductive alloy is 304 stainless steel, 70MN carbon steel or G60 steel material.

The second alloy is an alloy with strong magnetic permeability, such as 45# steel or chromium 12 steel material.

Fig. 6 is a cross-sectional view of the die taken along a plane parallel to the central axis of the two pole heads, the cavity 26 being at the same height as the first alloy zone 24 and the second alloy zone 25.

As shown in fig. 8, the cross section of the chamber 26 is a closed circular arc surface formed by the inner arc 14, the outer arc 13, the first side wall 11 and the second side wall 12. Inner arc 14 refers to the arc near the center of the circle and outer arc 13 refers to the arc away from the center of the circle. The shape of the cavity 26 is similar to a portion of a ring magnet. Considering the shrinkage and deformation of the sintered magnet, the outer arc 13, the inner arc 14, the first side wall 11 and the second side wall 12 of the cavity 26 are properly adjusted within the scope of the present invention, and the size of the finished product is 0.7-0.9 of the size of the mold cavity, so that the sintered circular-arc magnet is more close to an ideal circular magnet after being spliced.

The mould further comprises an N-pole and an S-pole, each comprising a pole head 23, and a first magnetic field coil 21 wound on the pole head of the N-pole and a second magnetic field coil 22 wound on the pole head of the S-pole. The N pole and the S pole are respectively disposed at both sides of the female mold 20, so that the female mold 20 is placed in a parallel magnetic field formed by a magnetic field coil. The side surface area of the female die 20 accounts for 70% or more of the area of the N-pole or S-pole.

Fig. 9 is a schematic view showing the magnetic field condition when a parallel magnetic field is applied to the mold shown in fig. 5. The first magnetic field coil 21 and the second magnetic field coil 22 generate a magnetic field, and the magnetic field passes through the straight sides of the permalloy, the permalloy and the non-magnetic conductive alloy, and the straight sides of the non-magnetic conductive alloy and the pole head in a straight line. When the magnetic field passes through the bevel edge of the strong magnetic conductive alloy and the non-magnetic conductive alloy, the magnetic field passes through the bevel edge at a certain angle. Therefore, by the design of the mold 20, the magnetic lines of force inside the circular arc magnet pass through at a constant arc, and the magnet is oriented in the same direction as the anisotropic pole ring magnet.

The parallel magnetic field passes through the chamber, and both the inlet of the magnetic force line in the chamber and the outlet of the magnetic force line form a certain angle relative to the closed circular arc surface. As shown in fig. 15, let an angle between an entrance of the magnetic field lines and the closed arc surface be α, an angle between an exit of the magnetic field lines and the closed arc surface be β, and an angle difference γ | - α - β | <70 ° between the exit of the magnetic field lines and the entrance thereof.

The distance between the two straight sides of the high-permeability alloy and the non-magnetic/weak-permeability alloy is greater than half of the length of the arc-shaped cavity in the magnetic field direction, and the length of the magnetic field direction refers to the projection length of the arc-shaped cavity in the magnetic field direction.

Example 2

FIG. 7 is another schematic view showing the structure of a mold for producing a magnet having a circular arc shape with a polar anisotropic orientation. The main difference from fig. 5 is that the inverted Y-shape has the opposite orientation of the opening and the position of the circular arc chamber in the mold changes. By adjusting the position of the arc-shaped cavity, the bending direction of the magnetic lines of force in the magnet can be changed. Fig. 10 is a schematic view of the magnetic field condition when the parallel magnetic field is applied to the mold shown in fig. 7.

Fig. 9 is another exemplary view showing a magnetic field in the magnet when the parallel magnetic field is applied to the mold shown in fig. 7. The first magnetic field coil 21 and the second magnetic field coil 22 generate a magnetic field, and the magnetic field passes through the straight sides of the permalloy, the permalloy and the non-magnetic conductive alloy, and the straight sides of the non-magnetic conductive alloy and the pole head in a straight line. When the magnetic field passes through the bevel edge of the strong magnetic conductive alloy and the non-magnetic conductive alloy, the magnetic field passes through the bevel edge at a certain angle. By adjusting the positions of the permalloy and the non-permalloy in the cavity 26 and the mold 20, the bending direction of the magnetic force lines in the circular arc magnet can be changed. In comparison with fig. 9, only the magnetic flux lines in the magnet are bent in different directions. After the two magnets are assembled into a circular ring magnet, N, S aggregation can occur, and finally, a waveform with sinusoidal surface magnetic flux density distribution is formed.

Example 3

Fig. 3 and 4 are a perspective view and a cross-sectional view of an arcuate magnet 10 produced by using the mold shown in fig. 7. 11 ', 12' are two end faces of the magnet, and 13 ', 14' are two arc faces of the magnet. As can be seen from the orientation of the magnets, the entrance and exit of the magnetic field lines inside the magnets, with respect to the end face 12 ', present different angles with respect to the end face 12'. By assembling two arc magnets 10 oriented in this manner, a configuration (shown by oblique lines in the drawing) in which one magnetic pole of the ring magnet having pole anisotropy shown in fig. 16 is the same can be obtained. It should be noted that the magnetic flux density distribution on the surface can be formed into a sine-shaped waveform as long as the magnets can form N poles or S poles which are gathered together, and the bending direction of the magnetic lines of force in the magnet is not required. In addition, the bending direction of the magnetic force lines in the magnet can be changed by adjusting the position and shape of the cavity in the mold. All the arcuate magnets 10 are assembled into a ring, and a ring magnet having polar anisotropy can be formed.

Figure 12 is another illustration of the positional relationship of the bevel edge of the die where the first and second alloy regions meet and the cavity. As can be seen, the length of the oblique sides of the permalloy 25 and the non-permalloy 24 in the direction perpendicular to the parallel magnetic field does not exceed the arc-shaped chamber 26. The magnetic force lines in the circular arc magnets produced in this way are not the requirement of complete heteropolar magnets and cannot meet the requirement of the utility model.

Example 4

An alloy is produced by high-frequency melting NdPr, Dy, Co, Al, Fe, Cu, Ga, Zr, and ferroboron with a purity of at least 99% by weight in an argon atmosphere, and casting the melt onto a chill roll, the alloy having, in mass%, 30% NdPr, 0.5% Dy, 1.0% Co, 0.5% Al, 0.15% Cu, 0.10% Ga, 0.12% Zr, 0.98% B, and the balance iron and unavoidable impurities. The alloy was subjected to hydrogenation pulverization into coarse powder, which was then subjected to jet milling to obtain magnetic powder having an average particle size of 3.1 μm. Adding a lubricant accounting for 0.2 wt% of the magnetic powder into the jet mill magnetic powder, mixing for 2h, and performing compression molding under an oriented magnetic field and a mold shown in figure 5 to obtain a blank. The first alloy material of the die is 304 stainless steel, and the second alloy material is 45# steel. Then the green body is put into a vacuum sintering furnace and sintered for 6 hours at 1060 ℃. Cooling after heat preservation, and performing primary tempering treatment at 900 ℃ for 3 h. Secondary tempering treatment is carried out at 520 ℃ for 5 h. And cooling and discharging to obtain the sintered neodymium-iron-boron magnet. The sintered magnet after the heat treatment was processed into a magnet having an outer arc radius of 88mm, an inner arc radius of 75mm and a central angle of 7.5 °, to thereby obtain an arc-shaped heteropolarity sintered magnet.

Example 5

The same formulation and milling process as in example 4 were used to obtain magnetic powder, which was then pressed and molded in an oriented magnetic field and a mold as shown in fig. 7 to obtain a green body. The first alloy material of the die is G60 steel, and the second alloy material is chromium 12 steel. Then the green body is put into a vacuum sintering furnace and sintered for 6 hours at 1060 ℃. Cooling after heat preservation, and performing primary tempering treatment at 900 ℃ for 3 h. Secondary tempering treatment is carried out at 520 ℃ for 5 h. And cooling and discharging to obtain the sintered neodymium-iron-boron magnet. The sintered magnet after the heat treatment was processed into a magnet having an outer arc radius of 88mm, an inner arc radius of 75mm and a central angle of 7.5 °, to thereby obtain an arc-shaped heteropolarity sintered magnet.

Comparative example 1

Magnetic powder was obtained by the same formulation and milling process as in example 4, and then molded in an oriented magnetic field and mold as shown in fig. 13. Fig. 13 is a schematic view showing the orientation of magnetic powder directly into the arc chamber in a conventional die, parallel magnetic field. The entire mold 20 has: the pair of symmetrical field coils 21 and 22 and the pole head 23 form a parallel magnetic field M. The non-magnetic conductive alloy area 24 'and the strong magnetic conductive alloy area 25' form a female die in parallel. In the female die there is a circular arc shaped cavity 26' consisting of an outer arc, an inner arc and two side walls.

The material of the non-magnetic conductive alloy area 24 'of the die is 70MN carbon steel, and the material of the magnetic conductive alloy area 25' is 45# steel. Then sintered at 1060 ℃ for 6 h. Cooling after heat preservation, and performing primary tempering treatment at 900 ℃ for 3 h. Secondary tempering treatment is carried out at 520 ℃ for 5 h. And cooling and discharging to obtain the sintered neodymium-iron-boron magnet. The sintered magnet after the heat treatment was processed into a magnet having an outer arc radius of 88mm, an inner arc radius of 75mm and a central angle of 7.5 degrees, thereby obtaining an arc-shaped sintered magnet.

The arcuate magnets of example 4, example 5, and comparative example 1 were assembled into a ring, and after magnetization, the surface magnetic flux density of the magnets was measured, and the measurement results are shown in fig. 14. As is clear from fig. 14, the surface magnetic flux density waveforms of examples 4 and 5 are sinusoidal, and have a waveform matching that of a rational anisotropic toroidal magnet. The surface magnetic flux density waveform of comparative example 1 exhibited a trapezoidal shape. Therefore, rotors with low cogging torque were obtained using the magnets of examples 4 and 5.

According to fig. 15, 3 × 3 pieces were processed at the inlet and outlet of example 4 and comparative example 1, respectively, and the flux in the direction of X, Y was measured to calculate the angle of the magnetic field lines with respect to the side 12. The test results are shown in table 1:

table 1: comparison of magnetic lines of force between example 4 and comparative example 1

	Entrance angle alpha (°)	Outlet angle beta (°)
			Example 4	27	75
Comparative example 1	0	0

It can be seen from example 4 that the angles of the magnetic lines of force at the entrance and the exit are different, which indicates that the magnetic lines of force of the magnet produced by the method of the present invention are deflected inside the magnet. Such a waveform of the magnetic flux density on the magnet surface appears as a sine wave, and the cogging torque of the rotor can be reduced.

Example 6

An alloy is produced by high-frequency melting NdPr, Dy, Co, Al, Fe, Cu, Ga, Zr, and ferroboron with a purity of at least 99% by weight in an argon atmosphere, and pouring the melt onto a chill roll, the alloy having, in mass%, 29.5% NdPr, 0.5% Dy, 1.5% Co, 0.1% Al, 0.17% Cu, 0.10% Ga, 0.18% Ti, 0.98% B, and the balance iron and unavoidable impurities. The alloy was subjected to hydrogenation pulverization into coarse powder, which was then subjected to jet milling to obtain magnetic powder having an average particle size of 2.9 μm. Adding a lubricant accounting for 0.2 wt% of the mass of the magnetic powder into the jet mill magnetic powder, mixing for 2h, and performing compression molding under an oriented magnetic field and a mold shown in figure 7 to obtain a blank. And then, putting the blank into a vacuum sintering furnace, and sintering for 6 hours at 1050 ℃. Cooling after heat preservation, and performing primary tempering treatment at 900 ℃ for 3 h. Performing secondary tempering treatment at 500 ℃ for 5 h. And cooling and discharging to obtain the sintered neodymium-iron-boron magnet. The sintered magnet after the heat treatment was processed into a magnet having an outer arc radius of 80mm, an inner arc radius of 72mm and a central angle of 5 °, thereby obtaining an arc-shaped heteropolarity sintered magnet. This product is designated A1.

The sintered magnet with polar anisotropy was subjected to Tb grain boundary diffusion treatment after removing oleic acid, wherein the diffusion amount of Tb was 0.5 wt%, in this example, the grain boundary diffusion was treated by thermal spraying, Tb was sprayed on the surface of the magnet to a thickness of 20 μm, and the treated sample was designated as A2. The results of measuring the magnetic properties of the magnets A1 and A2 are shown in Table 2.

Table 2: magnetic Property testing of samples A1, A2

Figure 563030DEST_PATH_GDA0003008532990000141

After the heteropolarity magnet is subjected to diffusion treatment, the remanence of the magnet is reduced by about 0.025T. The coercive force is increased by 648 kA/m.

The performance of the sample A1 non-diffused heteropolarity magnetite is 50M, and the product Hcj is too low to meet the use requirement of the motor on temperature resistance (180 ℃). The Hcj of the sample A2 reaches 1798kA/m after the diffusion technology is used, and the use requirement of the motor can be met.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A mold for manufacturing a pole anisotropic orientation magnet, comprising:

and the cavity is in an arc shape and is positioned in the first alloy area.

2. The die of claim 1, wherein the cavity block is a rectangular body, the first alloy region is inverted Y-shaped in the rectangular body, and the second alloy region is filled on both sides of the inverted Y-shaped side line.

3. The mold of claim 2, wherein the filling is a symmetrical filling.

4. The mold of claim 2 or 3, wherein the inverted Y-shaped edge comprises two diagonal edges and two horizontal edges; the two inclined side lines and the two horizontal side lines are in axial symmetry by taking the horizontal line as an axis.

5. The mold according to claim 1 or 2, wherein the first alloy zone comprises a zone a, a zone B and a zone C, wherein the zone a is a rectangular zone surrounded by two intersections of the hypotenuse line with the edge line of the female mold, and two vertices near the female mold; the region B is a trapezoidal region formed by two intersection points of the inclined sideline and the horizontal sideline and two intersection points of the inclined sideline and the female mould sideline; the region C is a rectangular region formed by two intersection points of the inclined sideline and the horizontal sideline and two intersection points of the horizontal sideline and the female die sideline.

6. The mold of claim 1, wherein the second alloy zone comprises zone D and zone E, each of zone D and zone E being surrounded by an intersection of a bevel edge line and a female mold edge line, an intersection of a bevel edge line and a horizontal edge line, an intersection of a horizontal edge line intersecting a bevel edge line and a female mold edge line, and a female mold vertex closest to the horizontal edge line.

7. The mold of claim 2, wherein the second alloy zone comprises zone D and zone E, each of zone D and zone E being surrounded by an intersection of a bevel edge line and a female mold edge line, an intersection of a bevel edge line and a horizontal edge line, an intersection of a horizontal edge line intersecting a bevel edge line and a female mold edge line, and a female mold vertex closest to the horizontal edge line.

8. The mold of claim 5, wherein the second alloy zone comprises zone D and zone E, each of zone D and zone E being surrounded by an intersection of a bevel edge line and a female mold edge line, an intersection of a bevel edge line and a horizontal edge line, an intersection of a horizontal edge line intersecting a bevel edge line and a female mold edge line, and a female mold apex closest to the horizontal edge line.

9. The mold according to any one of claims 6 to 8, wherein the regions D and E are axisymmetric with respect to a horizontal line.

10. The die of claim 1, wherein the first alloy is a non-magnetically permeable or less magnetically permeable alloy.

11. The die of claim 10, wherein the first alloy is a non-magnetic alloy.

12. A mould according to claim 1 or 10, wherein the second alloy is a magnetically permeable alloy.

13. The mold according to claim 1, wherein the cross section of the cavity is a closed circular arc surface consisting of an inner arc, an outer arc and two side walls; the inner arc refers to an arc close to the center of a circle, and the outer arc refers to an arc far away from the center of a circle.

14. The mold according to claim 5, wherein the cross section of the cavity is a closed circular arc surface consisting of an inner arc, an outer arc and two side walls; the inner arc refers to an arc close to the center of a circle, and the outer arc refers to an arc far away from the center of a circle.

15. The mold according to claim 6, wherein the cross section of the cavity is a closed circular arc surface consisting of an inner arc, an outer arc and two side walls; the inner arc refers to an arc close to the center of a circle, and the outer arc refers to an arc far away from the center of a circle.

16. The mold according to claim 7, wherein the cross section of the cavity is a closed circular arc surface consisting of an inner arc, an outer arc and two side walls; the inner arc refers to an arc close to the center of a circle, and the outer arc refers to an arc far away from the center of a circle.

17. The mold according to claim 8, wherein the cross section of the cavity is a closed circular arc surface consisting of an inner arc, an outer arc and two side walls; the inner arc refers to an arc close to the center of a circle, and the outer arc refers to an arc far away from the center of a circle.

18. The mold according to claim 12, wherein the cross section of the cavity is a closed circular arc surface consisting of an inner arc, an outer arc and two side walls; the inner arc refers to an arc close to the center of a circle, and the outer arc refers to an arc far away from the center of a circle.

19. The mold of claim 14 wherein said cavity is located entirely within said region B.

20. A die as claimed in any one of claims 13 to 19, wherein the first alloy region, second alloy region and cavity are of equal height.

21. The mold according to any one of claims 13-19, further comprising N and S poles, each comprising a pole head and a magnetic field coil wound around the pole head.

22. A mold as claimed in claim 21, wherein N and S poles are provided on both sides of the female mold, respectively, so that the female mold is placed in a parallel magnetic field formed by a magnetic field coil.

23. A mould as claimed in claim 22, wherein the female mould has a side surface area which is more than 70% of the area of the N or S pole.

24. The mold of claim 22 or 23, wherein the parallel magnetic field passes through the chamber, and both the entrance of the magnetic field lines and the exit of the magnetic field lines inside the chamber are at an angle with respect to the closed circular arc.

25. The die of claim 24, wherein the angle difference between the exit of the magnetic field lines and the entrance thereof is less than 70 °.

26. The mold of claim 18, wherein the distance between the two straight sides of the magnetically permeable strong alloy and the magnetically non/weakly permeable alloy is greater than half of the length of the arc-shaped chamber in the magnetic field direction, and the length of the magnetic field direction refers to the projection length of the arc-shaped chamber in the magnetic field direction.

27. A magnet with polar anisotropic orientation, characterized in that the entrance of the magnetic lines of force of the magnet and the exit of the magnetic lines of force of the magnet have an angular difference.

28. A magnet according to claim 27, wherein the angular difference is <70 °.

29. The magnet according to claim 28, wherein the angular difference is 5-60 °.

30. The magnet according to any one of claims 27 to 29, wherein the shape of the magnet having the anisotropic pole orientation is an arc shape.

31. The magnet according to claim 30, wherein the shape of the magnet with the anisotropic orientation is the same as the shape of the cavity according to any one of claims 13 to 18.

32. A toroidal magnet comprising a combination of magnets having anisotropic polarity orientations according to any one of claims 27 to 31.

33. A rotor for an electric machine comprising the anisotropically oriented magnet according to any one of claims 27 to 31 and/or the toroidal magnet according to claim 32.

34. An electric machine comprising the anisotropically oriented magnet according to any one of claims 27 to 31, the toroidal magnet according to claim 32, or the motor rotor according to claim 33.