JP2005050988A - Sheet-like resin magnet and magnet motor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet-like resin magnet and a magnet motor using the same wherein the magnetic characteristic of a crystal magnetic anisotropical magnetic powder can be utilized as much as possible and the degree of freedom in design is high. <P>SOLUTION: The sheet-like resin magnet wherein crystal magnetic anisotropical magnetic powder is contained in a resin is provided with an internal layer in a direction perpendicular to the sheet face and a surface layer on both sides of the internal layer, and a bending elasticity ratio of the surface layer to the internal layer is 1.0-2.0 and its orientation ratio is 1.0-1.2. Thus, such a sheet resin magnet that can sufficiently demonstrate magnetic characteristic by the filling volume of a crystal magnetic anisotropical magnetic powder and is high in the degree of freedom in design can be obtained. Furthermore, the sheet resin magnet is fixed as a circular magnet on the inner wall of a housing, resulting in a magnet motor with a superior characteristic. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sheet-shaped resin magnet, and more particularly to a thin flexible sheet-shaped resin magnet containing crystalline magnetic anisotropic magnetic powder that can be used in a small motor.

2. Description of the Related Art In recent years, small and energy-saving products have been demanded in electronic devices and the like, and thus small magnet motors incorporating annular permanent magnets are widely used. As the annular permanent magnet, since it is required to reduce the thickness and cost and to reduce the cost, a sheet-like resin magnet that can be freely changed in size by cutting after molding is preferably used. Such a sheet-like resin magnet is composed of a binder resin such as rubber or plastic elastomer and a magnetic powder, and can be easily formed into an annular magnet by cutting and curling into a strip shape. Such an annular magnet can be fixed to the inside of the motor with no need for an adhesive or by a very simple adhesion by utilizing the shape restoring force of the magnet itself.

  Magnetic powder has isotropic and anisotropy. Since the sheet-like resin magnet using the isotropic magnetic powder does not need to orient the magnetic field at the time of molding, it can be relatively thinly formed by various forming methods such as roll rolling. However, since the isotropic magnetic powder has inferior magnetic properties as compared with the anisotropic magnetic powder, it has not yet been realized to have the desired high magnetic properties when it is made into a sheet-like resin magnet.

  On the other hand, anisotropic magnetic powders are often used as magnets for high-performance motors because, if properly oriented, the magnetic flux density is generated more efficiently than isotropic magnetic powders. When a sheet-shaped resin magnet is formed using such a magnetocrystalline anisotropic magnetic powder, which is an anisotropic magnetic powder, an external magnetic field is applied during molding in which the resin is in a fluid state or after molding with residual heat. Since it is necessary to align the orientation of the magnetic powder, an extrusion molding machine or an injection molding machine equipped with a magnetic field orientation mechanism is used.

  However, the sheet-shaped resin magnets obtained with these molding machines tend to have a lower magnetic property of the molded body as the surface area / volume ratio is increased.

On the other hand, there is a method of forming a thin sheet-shaped resin magnet by cooling and solidifying an intermediate body cut by extrusion or injection molding or calendering in an axial magnetic field orientation as necessary. It is disclosed.
JP 2000-341916 A

  However, since a thermal history is applied again to a molded product that has received a thermal history during the molding process, the surface portion of the sheet becomes brittle due to thermal deterioration, and cracking occurs on the surface when processing such as curling. This phenomenon becomes more prominent as the filling rate of the magnetic powder increases.

  Accordingly, the present invention has an object to provide a sheet-shaped resin magnet that can make maximum use of the magnetic properties of the magnetocrystalline anisotropic magnetic powder and has a high degree of design freedom, and a magnet motor using the same. And

  The sheet-shaped resin magnet of the present invention is a sheet-shaped resin magnet in which crystalline magnetic anisotropic magnetic powder is contained in a resin, and is formed on an inner layer in a direction perpendicular to the sheet surface and on both sides of the inner layer. And a bending elastic modulus ratio between the surface layer and the inner layer is 1.0 to 2.0, and an orientation degree ratio is 1.0 to 1.2. As a result, a sheet resin magnet that can sufficiently exhibit magnetic properties with respect to the filling amount of the magnetocrystalline anisotropic magnetic powder and has a high degree of freedom in design can be obtained.

  The content of the magnetocrystalline anisotropy magnetic powder is 50 wt% ≦. Thereby, the more excellent sheet-like resin magnet is obtained.

  The sheet thickness t (mm) is 0.2 ≦ t ≦ 2.0. As a result, a thin sheet resin magnet capable of maximally utilizing the characteristics of the internal magnetic powder can be obtained, and both high performance and light thinness can be realized.

The magnet motor of the present invention is a magnet motor having an annular magnet formed on the inner wall of the housing with the sheet-like resin magnet described in claim 3, and the inner diameter D (mm) of the annular magnet is 2.23 t. It is characterized by being in a range of ^1.59 ≦ D. Thereby, the magnet motor which has the outstanding characteristic is obtained.

  Further, the surface of the annular magnet and the inner wall of the housing are in close contact, and the surface roughness Ry (μm) of the annular magnet is Ry ≦ 2.0. Thereby, a highly efficient magnet motor is obtained.

  As described above, the invention of the present application is a thin sheet shape that can sufficiently exhibit the performance of each constituent member by setting the Young's modulus ratio and the orientation degree ratio between the respective layers in the thickness direction of the sheet within preferable ranges. A resin magnet can be obtained. Moreover, since the surface of such a sheet-like resin magnet is smooth and has excellent flexibility, it can be a small-diameter annular magnet, and a small magnet motor having excellent performance can be obtained. Can be realized.

  As a result of various experiments, the inventor of the present application has found that the characteristics of the sheet-like resin magnet containing the magnetocrystalline anisotropic magnetic powder are caused by the characteristics of the inner layer and the surface layer of the sheet. It came.

  The sheet-shaped resin magnet obtained by extrusion molding is formed while receiving a strong friction that has a striped pattern on the surface. For this reason, the orientation of the magnetic powder on the surface of the compact is easily disturbed, and it is very difficult to fix the magnetic powder while maintaining the orientation by the magnetic field. It will not have. Therefore, when trying to improve the magnetic properties by increasing the filling ratio of the magnetic powder in the entire sheet, the composition of the composition decreases not only the surface layer but also the degree of orientation of the inner layer due to an increase in melt viscosity and heat dissipation. End up. The thinner the thickness of the entire sheet, the greater the proportion of such surface layers.

  In addition, the sheet-shaped resin magnet obtained by injecting the molding material into the mold while orienting the magnetic field cools and solidifies while the molding material flows in the mold. The powder is fixed without being sufficiently oriented. The ratio of the surface layer increases as the thickness of the sheet is reduced. Further, if the mold temperature is set to be high so as to improve the fluidity of the magnetic powder, the shape of the surface will be damaged when leaving the mold, and traces of injection gates and protrusion pins will remain deeply. When such a sheet-shaped resin magnet having irregularities on the surface is fixed inside the motor, the surface magnetic flux density of the irregularities locally changes, resulting in a problem that the operating noise of the motor increases. In addition, the sheet-shaped resin magnet by the injection molding needs to prepare a mold for each shape of the sheet-shaped magnet, and there is a problem in terms of cost and productivity.

  On the other hand, a sheet-shaped resin magnet obtained by orienting a magnetic sheet-shaped resin magnet once formed in a mold while heating it again is considered to improve the orientation rate of the surface layer. However, since heating is performed in a state where the sheet-shaped resin magnet is placed in the mold, the surface layer of the resin magnet in contact with the mold receives a heat history more than necessary, and the resin deteriorates. In particular, since rare earth magnet powder contains a large amount of transition metals, deterioration of the resin is promoted. Specifically, the molecular bond of the resin is broken to become a low molecular resin, or the broken molecules are gathered to be a deformed polymer resin. The surface layer made of the low-molecular resin is low in strength because the polymer entanglement is weak, and the surface layer made of a deformed polymer resin is very brittle because the flexibility is lowered. For this reason, when processing, such as curling, is performed, a crack will arise from the surface side, or peeling will arise partially.

  Therefore, the present invention provides a sheet-shaped resin magnet that can sufficiently exhibit the original characteristics of the resin and the magnetic powder throughout the sheet. Hereinafter, the sheet-like resin magnet and magnet motor of the present invention will be described in detail.

(Crystal magnetic anisotropic magnetic powder)
The magnetocrystalline anisotropic magnetic powder used in the present invention is not particularly limited, and is a rare earth magnetic material such as Sm ₂ Fe ₁₇ N ₃ such as Sm—Fe—N, SmCo ₅ (1-5), _{Sm 2 (Co, Fe, Zr} , V) 17 (2-17 series) Sm-Co-based, such _{as, Nd 2 Fe 14 B, Nd} -Fe-B -based, such as Nd 2 _{Fe 14} B, and Nd-Fe- A Ti—N system, an Nd—Fe—VN system, or the like can be used.

In particular, since it is preferable to use small particles with a smooth surface for the sheet-like resin magnet, Sm _x Fe _100-xyz N _y Ca from which fine particles with a smooth surface can be obtained without going through a pulverization step. _z is preferably used, and a part of Sm may be substituted with at least one of Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. . A part of Fe may be substituted with at least one of Co, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Hf, Nb, Ta, Mo, W, Ga, and Al. . In particular, by replacing a part of Fe with at least one of Ti, Mn, and Al, a magnetic powder having a preferable surface state can be obtained. The Sm content x is preferably 3 to 30 atomic%. If it is less than 3 atomic%, an α-Fe phase is formed, and the coercive force is particularly lowered. When it is more than 30 atomic%, Sm precipitates and the residual magnetization is lowered. Further, the content y of N is preferably 5 to 15 atomic%, and if it is less than 5 atomic%, almost no coercive force is exhibited, and if it exceeds 15 atomic%, an impurity composed of a rare earth metal or a nitride of iron itself. A phase is formed, and the magnetic properties are remarkably deteriorated. The Ca content z is preferably 0.001 to 0.30 atomic%, and if it is less than 0.001 atomic%, no improvement in magnetic properties can be obtained. Unevenness occurs and a preferable surface state cannot be obtained.

Here, a method for forming a rare earth-based magnetic powder is shown, but the present invention is not limited thereto. A raw material powder containing a rare earth oxide is used as a raw material. Metal calcium is added as a reducing agent to obtain a raw material mixture. Next, the raw material mixture is fired in an inert gas atmosphere and reduced and diffused to reduce rare earth oxides and the like in the raw material mixture. Subsequently, after evacuating the inside of the furnace, nitriding is performed by firing in an atmosphere containing nitrogen gas to obtain a nitride block. The nitride block is washed with water to remove by-products mainly composed of calcium. The magnetic powder thus formed has a uniform particle size, a specific surface area of 1 to ² m ² / g, and a substantially spherical shape. Further, the magnetic powder is excellent in coercive force, squareness ratio, and heat resistance.

  The magnetic powder used in the present invention is preferably subjected to a surface treatment. By modifying the particle surface, wettability with the resin, environmental resistance, and heat resistance can be improved. Specifically, a coating layer made of an inorganic substance and / or an organic substance can be provided on the particle surface by chemical conversion treatment, plating, vapor deposition, or the like. For example, a silica film can be formed on the particle surface by mixing magnetic powder and ethyl silicate and firing them under predetermined conditions. Further, when mixed with a silane coupling agent and fired under predetermined conditions, an organic chain can be formed on the silica film.

  In the present invention, the volume percentage of the magnetic powder in the sheet resin magnet is preferably 20 wt% or more, more preferably 30 wt% to 75 wt%, and even more preferably 40 wt% to 70 wt%, in consideration of magnetic characteristics and mechanical strength. It is preferable. Further, when the content is 50 wt% or more, particularly 50 wt% to 65 wt%, the relative ratio of the magnetic powder to the sheet thickness can be increased while maintaining reliability.

  In the present invention, the average particle size of the primary particles of the magnetic powder is preferably 1 μm to 50 μm, preferably 1 μm to 30 μm, and more preferably 1.5 μm to 20 μm. Since the primary particles defined in such a range are excellent in dispersibility in the liquid, the generation of huge secondary particles due to agglomeration can be suppressed even when the resin is filled in a high amount, and the local particles caused by the magnetic powder can be suppressed. Deterioration of the resin can be prevented. Moreover, since the magnetic powder having a particle size in the above range is excellent in orientation when a thin sheet magnet is used, good magnetic properties can be stably obtained. Here, the average particle diameter of the primary particles in the present specification is measured by a Fischer Subseizer (FSSS), and is obtained by measuring a specific surface area by an air permeation method. The average value of the primary particles obtained is shown. In particular, considering the bending strength of the sheet-shaped resin magnet, the Fischer diameter is preferably in the range of 1.5 μm to 20 μm, and when it is smaller than 1.5 μm, the occurrence rate of secondary particles in the resin as the surface area increases. Therefore, the desired sheet bending strength cannot be obtained. On the other hand, when the thickness is larger than 20 μm, when the sheet is curled, the particles are squeezed together and cracks occur, making it difficult to curl to a small diameter.

Further BET value of the magnetic powder is, ^2m 2 / g or less, and more preferably preferably 0.1-0.5 M ² / g, good sheet bending strength. When the BET value is larger than 2 m ² / g, the interface between the resin and the particle surface becomes complicated, which causes a problem that the flexibility necessary for curling cannot be secured, which is not preferable. Here, the BET value is indicated by the surface area of the magnetic powder measured by an adsorption method using nitrogen gas.

  As described above, when a magnetic powder having small particles and a large surface area is used, it is preferable to use a heavy metal deactivator together as a resin degradation inhibitor. As heavy metal deactivators, 1,2,3-benzotriazole, tolyltriazole, decamethylenedicarboxylic acid disalicyloyl hydrazide, N, N-bis {3- (3,5-di-t-butyl-4- Hydroxyphenyl) propionyl} hydrazide, 3- (N-salicyloyl) amino-1,2,4-triazole and the like can be used.

  When a resin magnet using a heavy metal deactivator is repeatedly heated, the heavy metal deactivator in the surface layer portion of the sheet may be deposited on the surface. For this reason, a difference appears notably in the deterioration state of the resin between the surface layer portion and the inner layer portion of the sheet. Further, the sheet resin magnet having a metal deactivator deposited on the surface has low adhesion to a housing such as a motor. Therefore, it is preferable that the sheet-shaped resin magnet of the present invention is continuously formed without repeatedly heating the molding composition.

(resin)
The resin used in the present invention is not particularly limited, but it is preferable to use a polymer resin such as a liquid crystal polymer resin, a thermoplastic elastomer, or a thermosetting elastomer because the bending strength is enhanced. As thermoplastic elastomers, styrene elastomer (SBC), vinyl chloride elastomer (TPVC), olefin elastomer (TPO), urethane elastomer (TPU), polyester elastomer, nitrile elastomer, polyamide elastomer (TPAE), fluorine Examples include elastomers, chlorinated polyethylene (CPE), 1.2 polybutadiene, trans 1.4IR, silicone elastomers, chlorinated ethylene copolymer alloys, and ester halogen polymer alloys. Among thermoplastic elastomers, those having a hard segment having particularly high fiber-based performance are preferable, and examples thereof include polyamide-based elastomers such as PPA, olefin-based elastomers such as PPS, polyester-based elastomers, and chlorinated polyethylene. Further, as the resin of the present invention, a resin obtained by mixing at least two kinds of thermoplastic resins having different melting points can be used. In such a resin, resin molecules having a high melting point are regularly aligned in a flow state in which resin molecules having a low melting point are melted. Thereby, the melting | fusing point range in the whole becomes broad, and a sheet-like magnet can be formed with high dimensional accuracy.

(Bending elastic modulus ratio)
The sheet-like resin magnet in the present invention comprises a crystalline magnetic anisotropic magnetic powder in the resin, and has an inner layer in the direction perpendicular to the sheet surface, that is, in the sheet thickness direction, It has a pair of surface layers so that the outer side of a layer may be pinched | interposed, The bending elastic modulus ratio of each said surface layer and the said inner layer is 1.0-2.0, It is characterized by the above-mentioned. Here, the flexural modulus ratio in the present specification is the measurement of the elastic modulus of each surface layer and inner layer using a universal testing machine (5566-STANDARD, manufactured by Instron) with the method defined in JIS K7171. The ratio between the high value layer and the low value layer is obtained. When the flexural modulus ratio is larger than 2.0, a difference in mechanical strength between the respective layers occurs, so that the flexibility of the entire sheet is lowered. Depending on the type of resin used, there are cases where the flexural modulus of the surface layer is higher than the flexural modulus of the inner layer, and conversely, it is low. Specifically, when the bending elastic modulus of the surface layer is larger than that of the inner layer, a phenomenon occurs in which polymer molecules cut by the deterioration of the resin of the surface layer crosslink starting from the cut portion. In the case of small, the polymer molecules are cut by the deterioration of the resin of the surface layer, and the entanglement between the polymers becomes weak, so that the breaking strength is low. When it curls and falls, the malfunction of breaking occurs. Further, considering the mass productivity, the bending elastic modulus ratio is preferably 1.0 to 1.5.

(Orientation ratio)
The sheet-shaped resin magnet of the present invention is characterized in that the degree of orientation ratio between each surface layer and the inner layer is 1.0 to 1.2. Here, in the present specification, the orientation degree ratio between the surface layer and the inner layer is obtained by determining the orientation degree by the ratio between the residual magnetic flux density of each layer and the volume filling rate of the magnetic powder. Expressed as a ratio to the layer. When the degree of orientation ratio is greater than 1.2, the layer having a low degree of orientation cannot sufficiently exhibit the performance of the magnetic powder, and the magnetic properties of the entire sheet are deteriorated. Specifically, a layer with a low degree of orientation has a low magnetic permeability and thus becomes a magnetic resistance, resulting in a problem that the amount of magnetic flux that can be extracted from the working surface is reduced.

  The sheet-shaped resin magnet of the present invention has a substantially uniform thickness as a whole. When the sheet thickness t is set to 2.0 mm or less, more preferably 1.5 mm or less, the effect of the present invention is particularly remarkable, and the initial demagnetization factor can be 10% or less. In this way, a thin sheet resin magnet that can make the best use of the characteristics of the internal magnetic powder is obtained, and a sheet resin magnet that can achieve both high performance and light thinness can be obtained. In the sheet-like resin magnet of the present invention, the sheet thickness t (mm) is preferably 0.2 ≦ t ≦ 2.0, more preferably 0.2 ≦ t ≦ 1.5, in consideration of workability. It is.

(Magnet motor)
The magnet motor of the present invention has an annular magnet formed by curling the sheet-shaped resin magnet so that the inner diameter D is in the range of 2.23t ^1.59 ≦ D, and the surface roughness Ry (μm) of the annular magnet. ) Is characterized in that Ry ≦ 2.0. As a result, an excellent annular magnet with extremely low cracks and irregularities in the annular magnet and a low surface resistivity has a very low contact resistance with the inner wall of the housing of the motor, etc., and can be fixed in close contact. A magnet motor capable of fully exhibiting the original magnetic characteristics of the sheet without being received is obtained. Here, in the present specification, the surface roughness Ry is determined by the maximum height Ry measuring method defined in JIS B0601-1994.

  Below, the Example which concerns on the sheet-like resin magnet of this invention and a magnet motor using the same is demonstrated along the formation method of this invention.

  93 wt% of Sm-Fe-N-Ca-based anisotropic magnetic powder having an average particle size of 2.5 μm, 6.3 wt% of polyamide elastomer, 0.5 wt% of silane coupling agent, 0.2 wt% of stearic acid, The molding composition contained is mixed with a Henschel mixer and then kneaded with a twin screw extruder to form pellets.

  The obtained pellets are put into a single screw extruder, and the molten compound is extruded in a sheet form from a die having a diameter of 5 mm to the side. The tip of the molten compound is placed in a molten state on a metallic rotating conveyor existing in a magnetic field atmosphere. The rotational speed of the rotary conveyor is adjusted so that the film thickness of the sheet is 0.9 mm when the compound tip is pulled by the rotary conveyor.

The sheet-shaped resin magnet thus obtained is cut into three equal parts in the direction parallel to the surface, and the first surface layer, the inner layer, and the second surface layer each having a thickness of 0.3 mm And When the flexural modulus of each layer was measured with a universal testing machine (Instron, 5566-STANDARD), the flexural modulus ratio between each surface layer and the inner layer was 300 MPa, 280 MPa, and 295 MPa, respectively. 1.07 and 1.01. Further, each layer is cut into a disk shape having a diameter of 10 mm in the thickness direction, and eight of these are laminated to form a cylindrical bonded magnet having a diameter of 10 mm × 2.4 mm. When the residual magnetic flux density of the cylindrical bonded magnet thus obtained was measured with a BH curve tracer, it was 8500 G, 8600 G, and 8550 G, respectively, and the ratio of the residual magnetic flux density between each surface layer and the inner layer was 1. 01. In addition, the density of the molded body of each layer is 5.1 g / cm ³ in every layer, and the filling amount of the magnetic powder is almost equal. From these, the degree of orientation ratio between each surface layer and the inner layer is 1.01.

  Using the same pellets as in Example 1, the molten compound is extruded vertically downward from a circular die having a diameter of 5 mm. Immediately after that, it is introduced into a rotating metal mold that exists in the magnetic field orientation atmosphere and the interval is set to 0.9 mm, and is cooled and solidified to obtain a sheet magnet oriented in the sheet thickness direction.

The sheet-like resin magnet thus obtained was measured in the same manner as in Example 1. The bending elastic moduli of the first surface layer, the inner layer, and the second surface layer were 300 MPa, 290 MPa, and The bending elastic modulus ratio between each surface layer and the inner layer is 1.03 and 1.05. Moreover, when the residual magnetic flux density of the cylindrical bonded magnet composed of the first surface layer, the inner layer, and the second surface layer obtained in the same manner as in Example 1 was measured with a BH curve tracer, 8500G and 8600G, respectively. , And 8550G, and the ratio of the residual magnetic flux density between the respective layers is 1.01. In addition, the density of the molded body of each layer is 5.1 g / cm ³ in every layer, and the filling amount of the magnetic powder is almost equal. Therefore, the orientation ratio between each surface layer and the inner layer is 1 .01.

  The sheet-shaped resin magnet having a sheet thickness of 0.9 mm obtained in Example 1 and Example 2 is curled so as to have an inner diameter of 5.0 mm to obtain an annular magnet. The surface roughness of the annular magnet thus obtained is 0.8 μm when the surface roughness Ry (μm) of the annular magnet is measured with a stylus type surface roughness measuring machine, and has an excellent surface state. Can be confirmed. A magnet motor in which such an annular magnet is closely attached to the inner wall of the motor housing has very low resistance at these interfaces, and can exhibit excellent magnetic properties.

(Comparative Example 1)
The same pellets as in Example 1 are put into a single screw extruder and extruded into a sheet form from a 1.5 mm × 20 mm die. The obtained sheet-shaped resin magnet is put into a mold and heated, compressed, and cooled in a magnetic field to obtain a magnetically oriented sheet-shaped resin magnet. When the sheet-like magnet thus obtained is measured in the same manner as in Example 1, the degree of orientation difference between each surface layer and the inner layer is 1.03. On the other hand, when the bending elastic modulus of the cylindrical bonded magnet composed of the first surface layer, the inner layer, and the second surface layer is measured in the same manner as in Example 1, it becomes 800 MPa, 310 MPa, and 805 MPa, respectively. It can be confirmed that the resin of the surface layer is deteriorated by the influence of the above. When such a sheet-shaped resin magnet having a thickness of 1.5 mm is curled so as to have an inner diameter of 5.0 mm to form an annular magnet, a crack that can be visually confirmed is generated on the surface. When the surface roughness Ry (μm) of such an annular magnet is measured, it becomes 6.2 μm. When such an annular magnet is incorporated in a motor and put to practical use, the resistance of each interface is large and the magnet motor has low characteristics.

(Comparative Example 2)
The same pellets as in Example 1 are put into a single screw extruder equipped with a magnetic field orientation mechanism in the vicinity of a die, and a solid compound is extruded sideways from a 0.9 mm × 20 mm die. When the sheet-like magnet thus obtained was measured in the same manner as in Example 1, the bending elastic moduli of the first surface layer, the inner layer, and the second surface layer were 350 MPa, 300 MPa, and 340 MPa, respectively. The flexural modulus ratio between each surface layer and the inner layer is 1.16 and 1.13. However, when the orientation ratio between each surface layer and the inner layer is measured, it is 1.33, and it can be confirmed that the degree of orientation varies between the inside and the outside of the sheet thickness. Such a sheet-shaped resin magnet cannot fully exhibit the performance of the magnetic powder, and a layer having a low degree of orientation becomes a magnetic resistance, and the magnetic flux density generated on the working surface of the sheet-shaped resin magnet decreases.

FIG. 1 is a schematic cross-sectional view showing the manufacturing method of the first embodiment. FIG. 2 is a schematic cross-sectional view illustrating the production method of the second embodiment.

Explanation of symbols

1: Extruder 2: Conveyor 3: Sheet-shaped melting compound 4: Magnetic field orientation coil

Claims (5)

A sheet-like resin magnet in which a crystalline magnetic anisotropic magnetic powder is contained in a resin,
An inner layer perpendicular to the sheet surface and surface layers on both sides of the inner layer;
A sheet-shaped resin magnet having a flexural modulus ratio between the surface layer and the inner layer of 1.0 to 2.0 and an orientation ratio of 1.0 to 1.2. The sheet-shaped resin magnet according to claim 1, wherein the content of the magnetocrystalline anisotropic magnetic powder is 50 wt% or more. The sheet-like resin magnet according to claim 1 or 2, wherein the sheet thickness t (mm) is 0.2≤t≤2.0. A magnet motor having an annular magnet formed by curling the sheet-like resin magnet according to claim 3 on an inner wall of the housing,
Magnet motor inside diameter D (mm) of the ring magnet is in the range of ^{2.23t 1.59} ≦ D. The magnet motor according to claim 4, wherein a surface roughness Ry (μm) of the annular magnet is Ry ≦ 2.0.

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