JP2015156405A - Anisotropic bond magnet and manufacturing method thereof and a motor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic bond magnet having satisfactory magnetic characteristics, which is formed with the orientation of magnetic powder aligned in one direction, a manufacturing method thereof and a motor using the same.

SOLUTION: The anisotropic bond magnet includes a magnet molding member 15 having an arc shape, which is formed of an anisotropic magnet compound including a thin magnetic powder 14 as a main component. The arc shaped magnet molding member 15 has a concave part 16 at the inner diameter side 15a, and the orientation direction of the magnetic powder 14 varies from the concave part 16 as a boundary. With this, the magnetic characteristics and the symmetry of density waveform in surface magnetic flux are ensured.

COPYRIGHT: (C)2015,JPO&INPIT

Description

  The present invention relates to an anisotropic bonded magnet, a manufacturing method thereof, and a motor using the same.

  In recent years, in order to cope with miniaturization and high performance of motors, there has been a demand for miniaturization and high performance of magnets attached to the stator (stator) of the motor. In order to realize this, an anisotropic bonded magnet having a controlled orientation direction is used.

  In general, the orientation direction of an anisotropic bonded magnet used for a stator of a motor is controlled so that the magnetic field is concentrated in the direction of the pole center by molding with a mold in an orientation magnetic field. For example, there is a method of forming an anisotropic bonded magnet by orienting an anisotropic bonded magnet oriented in a uniaxial direction by mechanically deforming the anisotropic bonded magnet oriented in a uniaxial magnetic field and then orienting it in a desired direction. . Thereby, the orientation direction of the anisotropic bonded magnet is controlled, and the magnetic field generated by the anisotropic bonded magnet is controlled to a desired strength.

  Below, the manufacturing method of the conventional anisotropic bonded magnet formed by making it deform | transform mechanically is demonstrated using Fig.5 (a)-(e). 5A to 5E are schematic views for explaining main steps of a conventional method for manufacturing an anisotropic bonded magnet. In the following, a method for manufacturing an anisotropic bonded magnet corresponding to one pole of a rotor having 10 poles will be described as an example.

  First, a conventional anisotropic bonded magnet uses a mold having a U-shaped cavity to form a U-shaped shape by aligning the orientation directions of the flaky magnetic particles 24 mixed in a predetermined amount in the same direction. The body 23 is molded.

  Next, as shown in FIG. 5A, the molded body 23 is placed in the vicinity of the center of the convex arc portion 22b on the lower mold 22, and the concave arc portion 21a of the upper mold 21 is molded. 23 to face.

  Next, as shown in FIG. 5B, a deformation load is applied to the upper mold 21 and the lower mold 22 in the vertical direction to mechanically deform the molded body 23. At this time, both ends of the U-shape of the molded body 23 are deformed along the convex arc portion 22 b of the lower mold 22. Accordingly, in the U-shaped molded body 23 shown in FIG. 5A, the magnetic powder 24 oriented in the same direction is deformed so that the major axis of the magnetic powder 24 is a convex arc at both ends of the U-shaped due to deformation. The portions 22b are aligned in the radial direction. On the other hand, in the center part of the U-shape of the molded body 23, the orientation direction of the magnetic powder 24 hardly changes, and the easy axis of magnetization of the magnetic powder 24 is formed in the radial direction of the convex arc portion 22b.

  Next, as shown in FIG. 5C, the U-shaped molded body 23 is further deformed along the convex arc portion 22 b of the lower mold 22.

  Then, as shown in FIG. 5D, the arc-shaped magnet molded body 25 shown in FIG. 5E is formed by mechanically deforming the U-shaped molded body 23 to a predetermined thickness. Is done.

  Thereby, after forming magnetic powder in a uniaxial direction in a magnetic field, it is mechanically deformed to control the orientation direction of the magnetic powder, thereby forming an anisotropic bonded magnet.

  Another method for controlling the orientation direction of the anisotropic magnet is, for example, a method in which the orientation direction is fixed in the radial direction (radial direction) and the surface magnetic flux is controlled by changing the magnet thickness to change the magnet shape. (For example, refer to Patent Document 1, Patent Document 2, and Patent Document 3).

  First, the conventional anisotropic bonded magnet of Patent Document 1 discloses a radially anisotropic cylindrical magnet having an orientation in a radial direction (radial direction). The magnetic field formed by the magnet is controlled by making the shape of the magnet facing the armature (rotor) corrugated and reducing the thickness of the adjacent magnetic pole surface.

  Moreover, in the conventional anisotropic bonded magnet of patent document 2, the composite bonded magnet which compounded the primary bonded magnet molded object containing a ferrite or soft magnetic iron, and the secondary bonded magnet magnetic body containing an anisotropic rare earth magnetic body. Is disclosed. And the distribution waveform of surface magnetic flux density is arbitrarily controlled by making the thickness of the secondary bond magnet magnetic body layer of a composite bond magnet into a dimension from which a space | interval part differs from a pole part. Here, the orientation of the anisotropic rare earth magnetic body, which is the secondary bonded magnet magnetic body, is controlled when molding in a magnetic field, and is formed by the magnetic field orientation including the thickness of the primary bonded magnet molded body. Is done.

  Moreover, the conventional anisotropic bond magnet of patent document 3 is disclosing the structure which integrally molded the polar anisotropic magnet arrange | positioned in the surface with respect to a stator in a magnetic field. And the thickness of the magnetic pole end part of an anisotropic bonded magnet is prescribed | regulated with respect to the thickness of radial direction, and generation | occurrence | production of cogging torque etc. is prevented by making magnetic flux distribution density close to sine wave distribution.

  In other words, as described above, the conventional anisotropic bonded magnet is formed by integrally molding the direction of anisotropy in a magnetic field, or by controlling the magnet thickness to an appropriate amount to improve motor characteristics. I am trying.

JP 2005-102499 A JP 2006-019573 A JP 2003-319585 A

  However, the magnet compact that constitutes the anisotropic bonded magnet mainly composed of the flake-shaped magnetic powder whose orientation direction is controlled by mechanical deformation is not mechanically flexible because the flake-shaped magnetic powder is poor in flexibility. There is a problem that it is difficult to deform. This is due to the fact that the magnetic powder is difficult to deform during compression molding because the shape of the magnetic powder is a flake shape. For this reason, in the magnet molded body, the deformation of the magnetic powder occurs discontinuously at a portion that is largely mechanically deformed (for example, a U-shaped root of the molded body). Thereby, when re-joining the magnetic particles, as shown in FIG. 5E, the orientation direction 25a1 of the magnetic particles 24 is disturbed and becomes non-uniform (particularly, the central portion 25a of the magnet compact 25) at the discontinuous portion. . As a result, there is a problem that the magnetic force toward the pole center is reduced, the magnetic characteristics are deteriorated, and the symmetry of the surface magnetic flux density waveform is deteriorated.

  In order to solve the above problems, the present invention provides an anisotropic bonded magnet in which the orientation direction is aligned in the pole center direction of the armature, and an anisotropy formed by controlling the orientation direction in the mechanical deformation process. An object of the present invention is to provide a method of manufacturing a bonded magnet and a motor including the same.

  In order to achieve the above object, the anisotropic bonded magnet of the present invention comprises an arc-shaped magnet molded body formed from an anisotropic magnet compound mainly composed of a thin-piece magnetic powder, and the arc-shaped magnet molded body. Has a concave portion on the inner diameter side, and has a configuration in which the orientation direction of the magnetic particles is different with the concave portion as a boundary.

  Thereby, the anisotropic bonded magnet which suppressed the disorder of the orientation direction of the part with a large deformation amount mechanically is realizable. As a result, the magnetic force toward the pole center can be improved.

  In addition, the anisotropic bonded magnet manufacturing method of the present invention includes a step of kneading thin-shaped anisotropic magnetic powder to form an anisotropic magnet compound, and forming the anisotropic magnet compound to form a U-shape. Forming a molded body of the present invention, and sandwiching the molded body between an upper mold having an arc-shaped concave portion and an arc-shaped lower mold having a convex portion at least in part, thereby forming an arc-shaped magnet Forming a body and magnetizing the magnet compact.

  As a result, when the magnet molded body is mechanically deformed into an arc shape, the deformation amount (displacement amount) of the magnetic powder oriented on the inner diameter side of the arc shape of the magnet molded body can be minimized, and disturbance in the orientation direction can be suppressed. . As a result, it is possible to easily produce an anisotropic bonded magnet oriented substantially in the polar center direction by reducing the region where the magnetic particles are oriented in a direction different from the polar center direction.

  Moreover, the motor of this invention is provided with the rotor which has the said anisotropic bonded magnet, and a stator. As a result, a small, high-performance motor with strong magnetic force can be realized.

  According to the present invention, an anisotropic bonded magnet that suppresses disturbance in the orientation direction of magnetic particles generated during mechanical deformation, and suppresses deterioration in magnetic properties and symmetry in the surface magnetic flux density waveform, and a method for manufacturing the same And a motor equipped with the same.

(A) Sectional drawing explaining the structure of the anisotropic bonded magnet in embodiment of this invention, (b) Sectional drawing explaining the structure of the magnetic powder which comprises the anisotropic bonded magnet of the embodiment Flowchart for explaining a method of manufacturing an anisotropic bonded magnet in the same embodiment (A)-(d) The schematic diagram explaining the main steps of the manufacturing method of the anisotropic bonded magnet of the embodiment A plan view illustrating the configuration of a rotor manufactured using the anisotropic bonded magnet of the same embodiment (A)-(e) The schematic diagram explaining the main steps of the manufacturing method of the conventional anisotropic bonded magnet

  Hereinafter, an anisotropic bonded magnet according to an embodiment of the present invention, a manufacturing method thereof, and a motor including the same will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment)
Below, the structure of the anisotropic bonded magnet in embodiment of this invention is demonstrated.

  Fig.1 (a) is sectional drawing explaining the structure of the anisotropic bonded magnet in embodiment of this invention. FIG.1 (b) is a figure explaining the structure of the magnetic powder which comprises the anisotropic bonded magnet of the embodiment. In this embodiment, for example, an arc-shaped anisotropic bonded magnet corresponding to one pole of a rotor having 10 poles will be described as an example. In the following description, the anisotropic bonded magnet may be referred to as a magnet molded body.

  As shown in FIG. 1A, the anisotropic bonded magnet 15 of the present embodiment has an arc shape in which, for example, at least two concave portions 16 having a semicircular cross section are formed on the inner diameter 15a side. A plurality of magnetic powders 14 are included. Further, as shown in FIG. 1B, the magnetic powder 14 is made of, for example, flaky NdFeB particles and has an easy magnetization axis B in the vertical direction with respect to the long axis 14a of the magnetic powder 14. And the recessed part 16 is provided in 0.01 to 40% of range with respect to the thickness of the radial direction of the anisotropic bonded magnet 15, for example.

  At this time, the anisotropic bonded magnet 15 of the present embodiment is formed with the magnetic powder 14 having, for example, three regions 17a, 17b, and 17c having different orientation directions, with the recess 16 as a boundary. Regions 17a corresponding to the recesses 16 are oriented in the orientation direction 17a1 shown in FIG. 1A so that the easy axis B of the magnetic powder 14 is formed in the radial direction (polar center direction) of the anisotropic bonded magnet 15. , The orientation direction of the magnetic powder 14 is aligned. In the region 17b, the easy axis B of the magnetic powder 14 is aligned along the orientation direction 17b1 shown in FIG. 1A from the end of the region 17b toward the region 17a. Similarly, in the region 17c, the magnetization easy axis B of the magnetic powder 14 is aligned along the orientation direction 17c1 shown in FIG. 1A from the end of the region 17c toward the region 17a.

  Thereby, the disorder of the orientation direction of the part with a large mechanical deformation amount is suppressed, and the magnetic force toward the pole center direction is improved.

  According to the present embodiment, it is possible to realize an anisotropic bonded magnet in which a disturbance in the orientation direction of a portion with a large mechanical deformation amount is suppressed by the recess 16 and the magnetic force in the pole center direction is improved.

  In the present embodiment, NdFeB particles are described as an example of the magnetic powder 14, but the present invention is not limited to this. For example, a composite in which an NdFeB material and a particulate SmFeN material are mixed may be used. At this time, generally, for the NdFeB material, for example, flaky magnetic powder 14 having an average particle diameter (major axis) of about 100 μm and a thickness (magnetization easy axis direction) of 20 μm to 40 μm is used.

  Below, an example of the manufacturing method of the anisotropic bonded magnet in embodiment of this invention is demonstrated using FIG. 2 and FIG. 3 (a)-(d).

  FIG. 2 is a flowchart for explaining a method of manufacturing an anisotropic bonded magnet in the same embodiment.

  As shown in FIG. 2, first, an anisotropic bonded magnet compound is formed by the following method (step S10).

  First, the anisotropic NdFeB magnetic powder and a novolac type epoxy resin having a softening temperature of 80 ° C. dissolved in acetone are sufficiently mixed with a kneader. Thereafter, acetone is vaporized and evaporated to form an epoxy resin film on the surface of the NdFeB magnetic powder.

  Similarly, SmFeN fine powder and a novolak type epoxy resin having a softening temperature of 80 ° C. dissolved in acetone are mixed with a kneader. Thereafter, acetone is vaporized and evaporated to form an epoxy resin film on the surface of the SmFeN fine powder.

  Then, NdFeB magnetic powder and SmFeN fine powder coated with epoxy resin, polyamide resin for imparting flexibility and adhesiveness, and lubricant are mixed with a mixer or the like to prepare a mixture. At this time, the mixing ratio of the NdFeB magnetic powder and the SmFeN fine particles was 3: 2. Further, the resin amount of the epoxy resin is 1.1 wt% in terms of the weight ratio (wt%) with respect to the whole, and the amount of the polyamide resin and the lubricant as the amount of other resins is 2 in weight ratio (wt%) in total. 0.8 wt%.

  Needless to say, the mixing ratio, weight ratio, and the like are not limited to the above values, and can be changed according to required characteristics.

  Then, the mixture is continuously charged into a gap between heated rolls, which is a kneading apparatus, for example, and kneaded to produce a kneaded product. Thereby, the polyamide resin is softened and kneaded into the mixture. At this time, since it is not necessary to heat the roll to a temperature at which the polyamide resin melts, the roll temperature during kneading is heated to, for example, 140 ° C. In addition, as a kneading apparatus, an extruder etc. can be used besides the method by the said roll.

  Then, the kneaded material obtained by kneading the magnetic powder material and the polyamide resin is cooled to room temperature, and then pulverized or crushed to prepare, for example, a granular powder having a particle size of 350 μm or less. At this time, for example, an imidazole fine powder curing agent having a curing start temperature of 170 ° C. is added to and mixed with the granular powder to prepare an anisotropic bonded magnet compound.

  Next, as shown in FIG. 2, a molded body is formed by the following method using the anisotropic bonded magnet compound (step S20).

  First, for example, a mold having a U-shaped cavity is prepared. The anisotropic bonded magnet compound is filled in the cavity of the mold.

  And the metal mold | die filled with the anisotropic bond magnet compound is arrange | positioned between the magnetic poles of the magnetic field generator which generate | occur | produces the magnetic field which orientates the magnetic powder of the filled anisotropic bond magnet compound in arbitrary directions. Thereafter, a magnetic field is generated between the magnetic poles of the magnetic field generator to orient the magnetic particles of the anisotropic bonded magnet compound in a predetermined direction.

  Then, compression molding is performed using, for example, a double-sided punch in a state where an orientation magnetic field is added to the magnetic powder of the anisotropic bonded magnet compound filled in the mold. As a result, a U-shaped molded body in which the orientation direction of the magnetic particles of the anisotropic bonded magnet compound is aligned in a certain direction (see, for example, FIG. 3A) is formed. At this time, the compression molding is performed, for example, under the conditions of a mold temperature of 160 ° C., a molding pressure of 150 MPa, an orientation magnetic field of 1.3 MA / m, and a molding time of 30 seconds. The magnetic field orientation molding is performed by, for example, orthogonal magnetic field molding. For example, when a rotor having a 10-pole configuration with Φ50 mm is formed, a U-shaped molded body is formed in a shape having a width of 14 mm and a height of 13 mm. However, it goes without saying that the dimensions of the U-shaped molded body change according to the size and the number of poles of the rotor.

  Then, after compression molding, at least the mold is demagnetized in the above state by, for example, a demagnetizing method in which an alternating magnetic field is applied to gradually attenuate the magnetic field strength. This is for preventing adhesion of the magnetic powder to the mold in the subsequent steps. Note that demagnetization may be performed by applying a DC magnetic field in the opposite direction to that during compression molding, in addition to applying an alternating magnetic field.

  Next, as shown in FIG. 2, a magnet molded body is formed by the following method using the molded body (step S30). Here, the detailed formation method of a magnet molded object is demonstrated using Fig.3 (a)-(d). 3A to 3D are schematic views for explaining main steps of the anisotropic bonded magnet manufacturing method according to the embodiment.

  First, an uncured body of a U-shaped molded body and a deformed mold composed of at least three parts of an upper mold 11, a lower mold 12, and a die (not shown) are placed in a thermostatic bath and contained in the molded body. It is heated to, for example, 160 ° C. below the curing start temperature of the curing agent. At this time, as shown to Fig.3 (a), the upper metal mold | die 11 has the concave circular arc part 11a which forms the outer diameter 15b (refer FIG. 1) shape of a desired rotor. The lower mold 12 has a convex arc portion 12b that forms a shape of an inner diameter 15a (see FIG. 1) of a desired rotor. On the convex arc portion 12b, at least two, for example, half A circular convex portion 12a is provided. Since the U-shaped molded body is not deformed in a magnetic field, the material of the upper mold 11 and the lower mold 12 does not need to be formed of a non-magnetic material. It is preferable to use a super hard material such as (WC). Moreover, the shape of the convex part 12a is arbitrary if it is a shape larger than the curvature of the convex circular arc part 12b. Moreover, the height of the convex part 12a is provided in the range of 0.01% to 40% with respect to the thickness of the radial direction of the anisotropic bonded magnet 15 described below, for example. Specifically, when the thickness of the anisotropic bonded magnet 15 is 1.5 mm, the height of the convex portion 12a is 10 μm (about 0.6%) or more and 500 μm (about 35%), preferably 50 μm or more. 150 μm. The circumferential width of the convex portion 12a is about 50 μm to 1500 μm, preferably 500 μm or more and 1000 μm.

  Then, as shown in FIG. 3A, the molded body 20 maintained at 160 ° C. includes a convex portion 12a in the vicinity of the center portion on the lower mold 12 and the U-shaped both ends of the molded body 20 include the convex portions 12a. Place and place as you do. Thereafter, the concave arc portion 11 a of the upper mold 11 is disposed so as to face the molded body 20. At this time, in order to arrange the U-shaped molded body 20 in the vicinity of the center portion of the lower mold 12, it is preferable to arrange, for example, using a positioning jig.

  Then, as shown in FIG. 3B, the molded body 20 is mechanically deformed by applying a deformation load of 20 MPa to the upper mold 11 and the lower mold 12 from above and below, for example, with a deformation time of 30 seconds. At this time, both end portions of the U-shape of the molded body 20 are deformed along the convex arc portion 12 b of the lower mold 12. Thus, in the U-shaped molded body 20 shown in FIG. 3A, the magnetic powder 14 with the easy magnetization axis oriented in the same direction (vertical direction) is deformed at both ends of the U-shaped by deformation. The long axes of 14 are aligned in the radial direction of the convex arcuate portion 12b. On the other hand, in the center portion of the U-shaped of the molded body 20, the orientation direction of the magnetic powder 14 is hardly deformed, and the easy axis of magnetization of the magnetic powder 14 is formed in the radial direction of the convex arc portion 12b.

  Then, as shown in FIG. 3C, when the U-shaped molded body 20 is further deformed, the molded body 20 is deformed by the convex portion 12a of the lower mold 12 so that the magnetic powder 14 in the central portion of the U-shaped shape. Deformation is limited while deformation is limited. That is, the convex portion 12 a prevents the magnetic powder 14 from being randomly deformed along the convex arc portion 12 b of the lower mold 12, and the orientation of the magnetic powder 14 in the center of the U-shaped portion of the molded body 20. The direction can be made uniform.

  Then, an arc-shaped magnet molded body 15 having a predetermined thickness is formed as shown in FIG. Here, the thickness (wall thickness) of the magnet molded body is set by regulating the positions of the upper mold 11 and the lower mold 12 after pressurization so as to be 1.5 mm, for example. At this time, the convex portion 12a of the lower mold 12 is transferred to the magnet molded body 15, and the arc-shaped magnet molded body 15 having the concave portion 16 shown in FIG. In addition, although not shown in FIG.3 (d), it cannot be overemphasized that the jig | tool which forms the taper-shaped side surface of the circular arc-shaped magnet molded object 15 is provided.

  Then, the magnet molded body 15 is cured by heating at a temperature equal to or higher than the curing temperature of the curing agent mixed in the magnet molded body 15.

  Next, as shown in FIG. 2, the magnet molded body 15 is magnetized by the following method to form an anisotropic bonded magnet (step S40). Magnetization of the magnet molded body 15 may be performed by the magnet molded body 15 alone. Usually, the magnet molded body 15 is magnetized by bonding a plurality of magnet molded bodies 15 to, for example, a rotor core. Therefore, in the following, a case where the magnet molded body 15 is magnetized after being formed into a rotor shape will be described as an example.

  First, a rotor is formed by adhering 10 arc-shaped magnet molded bodies 15 corresponding to, for example, one of 10 poles formed by the above method to a rotor core formed by laminating electromagnetic steel sheets, for example. To do. At this time, you may utilize the recessed part 16 of the magnet molded object 15 for the positioning at the time of rotor formation. Thereby, the magnet molded object 15 can be arrange | positioned accurately in the position facing the pole center direction.

  Then, the rotor is attached to a dedicated magnetizing yoke that can be magnetized in a predetermined direction and magnetized. At this time, the magnetizing yoke is designed and manufactured so that a sufficient magnetization amount can be obtained by substantially aligning the magnetizing direction with the orientation direction of the magnetic powder of each arc-shaped magnet molded body 15. Since the arc-shaped magnet molded body 15 has an easy magnetization axis in the orientation direction, the magnetization direction of the magnetized yoke does not necessarily match the orientation direction of the magnetic powder of the arc-shaped magnet molded body 15. Also good.

  By the manufacturing method of the present embodiment, a rotor (rotor core not shown) magnetized in a predetermined orientation shown in FIG. 4 is produced. Here, FIG. 4 is a plan view illustrating a configuration of a rotor manufactured using the anisotropic bonded magnet of the same embodiment.

  Moreover, a motor can be produced by combining a rotor composed of the anisotropic bonded magnet obtained as described above and a stator.

  As described above, according to the present embodiment, the disorder in which the orientation direction of the magnetic powder 14 in the portion having a large mechanical deformation amount is suppressed by the recess 16 and the magnetic force toward the pole center direction is improved. An easily bonded magnet can be produced easily.

  Moreover, according to this Embodiment, it is possible to utilize the recessed part 16 of the magnet molded object 15 for the positioning at the time of rotor formation. The rotor can be manufactured by accurately arranging the magnet molded body 15 with respect to the pole center position of the magnetized yoke designed exclusively for the orientation direction of the anisotropic magnet.

  In addition, according to the present embodiment, by using an anisotropic bonded magnet whose magnetic force in the direction of the pole center is improved, a small and high-performance motor with strong magnetic force can be realized.

  In the present embodiment, the cross-sectional shape of the convex portion of the lower mold is described as an example of a semicircular shape, but the present invention is not limited to this. For example, the cross-sectional shape may be a trapezoidal shape, a polygonal shape such as a triangular shape, or an egg shape. That is, any shape can be used as long as it can be deformed so as not to disturb the orientation direction of the magnetic powder at the center of the U-shaped shaped body when the shaped body is mechanically deformed. At this time, it goes without saying that the shape of the concave portion 16 formed on the inner diameter side of the anisotropic bonded magnet is also formed according to the shape of the convex portion of the lower mold.

  In the present embodiment, a U-shaped molded body has been described as an example, but the present invention is not limited thereto. For example, both ends of the molded body may be a shape that opens in a square shape or an R-shaped curve.

  In the present embodiment, specific numerical values have been described as examples. However, the present invention is not limited to the numerical values shown, and values of preferable conditions are set according to the shape, composition, characteristics, etc. of the anisotropic bonded magnet to be formed. It goes without saying that it is done. In particular, the range of the load when the molded body is mechanically deformed is, for example, 5 to 40 MPa, and it is preferable to adjust the load according to the conditions depending on the temperature at the time of deformation and the amount of resin contained in the magnet material.

  Moreover, although this Embodiment demonstrated by the example in which a hardening | curing agent hardens | cures after forming a magnet molded object, it is not restricted to this. For example, you may make it harden | cure after forming in a rotor shape.

  Examples of the present invention will be described below. In addition, this invention is not limited to a following example, Unless it changes the summary of this invention, it can change and use the material etc. to be used.

(Example)
(1) Production of anisotropic bonded magnet compound First, as described in the embodiment, an anisotropic NdFeB magnetic powder and SmFeN fine powder are dissolved in acetone, for example, a novolac type having a softening temperature of 80 ° C. Thoroughly mix the epoxy resin with a kneader. Thereafter, acetone was vaporized and evaporated to form an epoxy resin film on the surfaces of the NdFeB magnetic powder and the SmFeN fine powder.

  Then, NdFeB magnetic powder and SmFeN fine powder, a polyamide resin for imparting flexibility and adhesiveness, and a lubricant were mixed with a mixer or the like to prepare a mixture. At this time, the mixing ratio of the NdFeB magnetic powder and the SmFeN fine particles was 3: 2. The resin amount of the epoxy resin is 1.1 wt% in terms of the weight ratio (wt%) with respect to the total weight, and the resin amount of the polyamide resin and the lubricant is 2.8 wt% in terms of the weight ratio (wt%). .

  The above mixture was continuously put into a gap between rolls heated to 140 ° C., for example, and kneaded to prepare a kneaded product. This softened the polyamide resin and kneaded it into the mixture.

  The kneaded product was cooled to room temperature and then pulverized or crushed to prepare, for example, a granular powder having a particle size of 350 μm or less. At this time, an imidazole fine powdery curing agent having a curing start temperature of 170 ° C. was added to and mixed with the granular powder to prepare an anisotropic bonded magnet compound.

(2) Production of molded body Next, a molded body was formed using an anisotropic bonded magnet compound.

  First, for example, a die having a U-shaped cavity was filled with an anisotropic bonded magnet compound.

  A mold filled with the anisotropic bonded magnet compound is arranged between the magnetic poles of the magnetic field generator, and the magnetic powder of the anisotropic bonded magnet compound is oriented in a predetermined direction by applying a magnetic field. .

  Then, with the orientation magnetic field applied to the magnetic powder of the anisotropic bonded magnet compound filled in the mold, for example, compression molding is performed using a both-side punch, and a U-shaped molded body having a width of 14 mm and a height of 13 mm. Formed. At this time, the compression molding was performed, for example, under the conditions of a mold temperature of 160 ° C., a molding pressure of 150 MPa, an orientation magnetic field of 1.3 MA / m, and a molding time of 30 seconds.

(3) Production of Magnet Molded Body Next, a magnet molded body was produced using the above molded body.

  First, an uncured body of a U-shaped magnet molded body and a deformed mold comprising at least three parts of an upper mold 11, a lower mold 12, and a die (not shown) are left in a constant temperature bath at 160 ° C. and heated. did.

  Then, the magnet molded body maintained at 160 ° C. is arranged at the center part on the lower mold, the upper mold is arranged, and the lower mold and the upper mold are applied from above and below with a deformation load of 20 MPa in a deformation time of 30 seconds. The magnet molded body was deformed so that the thickness of the magnet molded body was 1.5 mm. At this time, the U-shaped molded body before deformation was 13 mm long and 14 mm wide. This is a size corresponding to one pole out of 10 poles when the outer diameter of the rotor is Φ50 mm.

  Then, the deformed arc-shaped magnet molded body for 10 poles was bonded to the rotor core to produce a rotor.

(4) Magnetization of rotor The rotor produced as described above was attached to a dedicated magnetizing yoke that can be magnetized in a predetermined direction, and magnetized. The magnetization condition at this time was set to 10 kA, for example, as a magnetization current.

(5) Characteristic comparison The flux value was compared with the conventional molded object with the single magnet molded object produced above. As a result, it was found that the magnet molded body produced in the present embodiment was improved by 4 to 5% with respect to the flux value of the conventional molded body.

  A rotor was produced using the magnet compact of the present invention, and the surface magnetic flux density waveform after magnetization was compared with that of a conventional rotor. As a result, it was found that the peak value of the surface magnetic flux density waveform was improved by about 3%.

  As a result of evaluating the motor characteristics, it was found that the distortion rate of the induced voltage waveform was improved and the symmetry of the surface magnetic flux density waveform was improved as compared with the conventional motor.

  As explained using the above examples, by forming a convex portion on the mold at the time of formation to form the anisotropic bonded magnet of the present invention, the uniformity of the magnetic powder orientation direction is improved and the magnet characteristics are excellent. It was confirmed that an anisotropic bonded magnet and a motor could be realized.

  The anisotropic bonded magnet of the present invention can improve the symmetry of magnetic properties and surface magnetic flux density waveform by concentrating the orientation of the easy axis direction of the magnetic powder at the pole center, so that the motor with reduced vibration and noise This is useful in the technical field of rotating machines.

11, 21 Upper mold 11a, 21a Concave arc part 12, 22 Lower mold 12a Convex part 12b, 22b Convex arc part 14, 24 Magnetic powder 14a Long axis 15, 25 Magnet molded body (anisotropic bonded magnet)
15a Inner diameter 15b Outer diameter 16 Recessed parts 17a, 17b, 17c Regions 17a1, 17b1, 17c1, 25a1 Orientation direction 20, 23 Molded body 25a Central part

Claims (7)

An arc-shaped magnet molded body formed from an anisotropic magnet compound mainly composed of flake-shaped magnetic powder,
The arc-shaped magnet molded body has a recess on the inner diameter side,
An anisotropic bonded magnet in which the orientation direction of magnetic powder is different with the recess as a boundary. Kneading the flaky magnetic powder to form an anisotropic magnet compound;
Forming the U-shaped molded body by molding the anisotropic magnet compound; and forming the molded body with an upper mold having a concave arc portion, and a convex arc formed with at least a convex portion. Sandwiching between a lower mold having a portion and forming an arc-shaped magnet molded body;
Magnetizing the magnet compact;
The manufacturing method of the anisotropic bonded magnet containing this. The method for manufacturing an anisotropic bonded magnet according to claim 2, wherein the convex portion has a curvature in cross section. The difference according to claim 2, wherein the convex portion of the lower mold is transferred to a surface of the arc-shaped magnet molded body facing the lower mold to form a concave portion in the arc-shaped magnet molded body. A method for producing an isotropic bonded magnet. The method for producing an anisotropic bonded magnet according to claim 2 or 3, wherein a height of the convex portion is 0.01% or more and 40% or less of a thickness of the magnet molded body. A rotor having the anisotropic bonded magnet according to claim 1;
A stator,
With motor. A rotor having an anisotropic bonded magnet formed by the manufacturing method according to any one of claims 2 to 5,
A stator,
With motor.

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