JP5880329B2 - Extrusion molding apparatus and bonded magnet extrusion molding method - Google Patents

Description

  The present invention relates to an extrusion apparatus and a bonded magnet extrusion method.

  A bonded magnet composed of a magnetic material and a resin as a binder of the magnetic material can be formed in a complicated shape as compared with a sintered magnet, and has excellent mechanical strength. Therefore, many bonded magnets are employed as electronic parts such as permanent magnet type synchronous motors such as DC motors and stepping motors, and magnet rolls for laser printers.

  Here, the magnetic powder includes an anisotropic material having magnetic anisotropy and an isotropic material having no magnetic anisotropy. Anisotropic materials must be anisotropicized by aligning the magnetization direction of the particles of the magnetic material in a certain direction when the magnet is manufactured. Such an operation is called “orientation”. The magnetic properties obtained in this way are relatively high. Isotropic materials do not need to be oriented but have relatively low magnetic properties.

  One method of forming an anisotropic bonded magnet is a method in which a bonded magnet composition composed of a magnetic material and a resin material is thermally cured while being melted in a mold while being magnetically oriented and extruded. Is known (Patent Document 1).

  On the other hand, as a thermosetting resin extrusion molding method, the thermosetting resin is supplied to an extruder equipped with a screw having a smooth portion at the tip portion, and a curing reaction is carried out in the gap between the smooth portion and the cylinder so that the external portion is directly exposed from the tip of the cylinder. It is known to extrude into (Patent Document 2).

JP 2004-158748 A Japanese Examined Patent Publication No. 6-11514

  However, the method of Patent Document 1 does not stabilize the moldability. In other words, the thermosetting reaction proceeds abruptly depending on the temperature and pressure, the composition of the thermosetting resin composition, the curing reaction proceeds locally, or the curing becomes insufficient. It was difficult to perform stable molding.

  FIG. 9 is a diagram showing a spider type anisotropic bonded magnet extrusion molding apparatus that has been widely used instead of the screw type, and FIG. 10 is a cross-sectional view taken along line AA in FIG. The screw 40 is not connected to the inner die 50, and the inner die 50 is fixed by a spider 96. There are a spider method and a spiral method for fixing the inner die, but in either method, the resin flow path changes drastically. In such a narrow place, there was a problem of local curing due to temperature and pressure distribution.

  Patent Document 2 discloses a method for extruding a thermosetting resin with an extruder equipped with a screw. According to this method, the moldability is improved. No technology has been proposed for extruding the anisotropic bonded magnet as described above by a screw method. Since Patent Document 2 does not consider magnetic field orientation, there is a problem that even if the method of Patent Document 2 is applied to forming an anisotropic bonded magnet, the orientation is disturbed and the bonded magnet cannot be strong.

  Accordingly, the present invention provides a bonded magnet extrusion molding apparatus and extrusion capable of stably forming a thermosetting resin with a screw extruder while obtaining an anisotropic bonded magnet without disturbing the orientation. An object is to provide a forming method.

  According to the present invention, the above problem is solved by the following means.

  The present invention is an extrusion molding apparatus for extruding a bonded magnet composition having an anisotropic magnetic material and a thermosetting resin, and an outer die having a through hole for molding the outer periphery of a cylindrical bonded magnet; An inner die that is disposed in the through hole and that molds the inner circumference of the bond magnet, and a screw that extrudes the material of the bond magnet, and the inner die is connected to the screw. An extrusion molding apparatus characterized in that it is rotatable, an orientation magnet is embedded in the inner die, and the orientation magnet is arranged up to an end of the outer die in the extrusion direction of the extrusion molding apparatus. It is.

  Further, the present invention is the above-described extrusion molding apparatus, wherein the orientation magnet end and the outer die end are arranged flush with each other in the extrusion direction of the extrusion molding apparatus.

  Further, the present invention is the above-described extrusion molding apparatus, wherein the orientation magnet is arranged so as to protrude from the end portion of the outer die in the extrusion direction of the extrusion molding apparatus.

  The present invention is the above-described extrusion molding apparatus, wherein the orientation magnet is exposed from the inner die.

  Further, the present invention is the above-described extrusion molding apparatus, wherein the inner die outermost part and the outer die outermost part are arranged flush with each other in the extrusion direction of the extrusion molding apparatus.

  Further, the present invention is a method of extruding a composition in which an anisotropic magnetic material and a thermosetting resin are mixed with a screw type extruder, and is connected to the screw so as to be rotatable. Using an extrusion molding apparatus in which an orientation magnet is embedded and the orientation magnet is arranged up to the end of the outer die in the extrusion direction of the extrusion molding apparatus, the inner die and the composition are rotated together. A method of extrusion molding a cylindrical bonded magnet, wherein the molding is performed by thermosetting.

  The present invention is also the above-described method for extruding a cylindrical bonded magnet, wherein the anisotropic magnetic material is Sm—Fe—N based magnetic powder.

  The present invention is also the above-described method for extruding a cylindrical bonded magnet, wherein the thermosetting resin is an epoxy resin.

  According to the present invention, a bonded magnet extrusion molding apparatus capable of obtaining an anisotropic bonded magnet without disturbing orientation while stably molding a thermosetting resin with a screw type extruder, and An extrusion method can be provided.

It is explanatory drawing which shows the extrusion molding apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows the magnetization direction of the magnet for orientation shown in FIG. It is an enlarged view of the metal mold | die part 2 shown in FIG. It is a figure explaining orientation angle (theta) of the bonded magnet molded article obtained by this invention. FIGS. 5A to 5D are views illustrating a part of the extrusion molding apparatus according to the embodiment of the present invention. It is a figure explaining orientation angle (theta) of the bonded magnet molded article obtained by the Example of this invention. It is a figure explaining orientation angle (theta) of the bonded magnet molded article obtained by the comparative example 1. FIG. It is a figure explaining orientation angle (theta) of the bonded magnet molded article obtained by the comparative example 2. FIG. It is explanatory drawing which shows the conventional extrusion molding apparatus. FIG. 10 is a sectional view taken along line AA shown in FIG. 9.

Hereinafter, an extrusion molding apparatus and an extrusion molding method according to the present invention will be described with reference to the drawings. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Further, in the following description, the same name and reference sign indicate the same or the same members in principle, and the detailed description will be omitted as appropriate.
Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory view (cross-sectional view) showing an entire extrusion molding apparatus according to an embodiment of the present invention. As shown in FIG. 1, the extrusion molding apparatus includes a screw part 1 for extruding a bonded magnet composition having an anisotropic magnetic material and a thermosetting resin to the front, an inner die 50 connected to the screw 40, and an outer die. 60 mold parts 2.
The outer die 60 has a through hole for forming the outer periphery of the cylindrical bonded magnet, and the inner die 50 for forming the inner periphery of the bonded magnet is disposed in the through hole. The inner die 50 is rotatable by being connected to the screw 40, and an orientation magnet 70 is embedded in the inner die 50.

  In the screw part 1, a bonded magnet composition in which an anisotropic magnetic material and a thermosetting resin are mixed is fed into the mold part 2 by a screw 40. The bonded magnet composition may be in the form of a lump or candy at room temperature. The bonded magnet composition is supplied from the hopper 80 into the cylinder 30. A cylinder 30 is provided around the outside of the screw 40. If necessary, the cylinder 30 can be heated so that the bonded magnet composition can be easily fed. However, this heating needs to be suppressed to such an extent that the cross-linking reaction of the bonded magnet composition does not start. Conversely, when the heat generation is increased by the shearing force generated by the screw 40 and the cylinder 30, the cylinder 30 may be cooled.

  The bonded magnet composition fed into the mold part 2 is shaped into a cylindrical shape by a space created by the outer diameter of the inner die 50 connected to the screw 40 and the inner diameter of the outer die 60. That is, the inner periphery of the formed cylindrical bonded magnet corresponds to the outer diameter of the inner die 50, and the outer periphery of the bonded magnet corresponds to the inner diameter of the outer die 60. The outer periphery and inner periphery of the bonded magnet molded product can be freely changed by changing the outer diameter of the inner die 50 and the inner diameter of the outer die 60.

  When the bonded magnet composition further advances forward, an orientation magnet 70 is embedded in the inner die 50. “Embedded” as used herein refers to a state where at least a portion is embedded in the inner die 50, and a portion may be exposed at a portion where the bonded magnet composition does not contact.

  An enlarged view of an example of the orientation magnet 70 is shown in FIG. This is an orienting magnet for forming an inner peripheral 6-pole bonded magnet, which is formed in a columnar shape and is made up of 6 magnet pieces. When it is desired to change the number of poles of the bonded magnet molded product, it can be dealt with by changing the number and shape of the magnet pieces. Further, the outer die 60 is preferably made of nonmagnetic steel so as not to form a magnetic circuit with the orientation magnet.

  When the bond magnet composition reaches a position where the orientation magnet 70 is embedded, the magnetic material in the bond magnet composition is oriented along the magnetic field generated by the orientation magnet. When proceeding further forward, the bonded magnet composition is heated by a heater (not shown), the crosslinking reaction of the thermosetting resin proceeds, and the orientation is fixed.

  Here, the orientation magnet 70 needs to be embedded in the inner die 50 up to the tip of the outer die 60. In other words, the orientation magnet 70 is arranged up to the end of the outer die 60 in the extrusion direction of the extrusion molding apparatus. Here, the end portion of the outer die 60 refers to an end portion at a portion where the bonded magnet composition and the inner diameter of the outer die 60 are in contact with each other on the discharge port side. For example, in the case of FIG. 1 and FIG. 5C, it refers to a portion illustrated as the outer die end portion 90. In the case of FIG. 5C, the outermost portion on the discharge port side is referred to as the outer die outermost portion 92. In the case of FIG. 1, the outer die end 90 is the same as the outermost part of the outer die.

  FIG. 3 is an enlarged view of the mold part 2 on the discharge port side of the extrusion molding apparatus. Here, the distance x is the distance between the end portion of the orientation magnet 70 and the outer die end portion 90. Here, if x = 0, the end portion of the orientation magnet 70 and the outer die end portion 90 are arranged to be flush with each other.

The bonded magnet composition rotates together with the inner die 50 that is connected to the screw 40 and rotates. Without the orientation magnet 70, the rotation of the bonded magnet composition is irregular. On the other hand, when the orientation magnet 70 is embedded in the inner die 50, the inner die 50 and the bond magnet composition in the section where the orientation magnet 70 is embedded due to magnetic adsorption between the orientation magnet 70 and the bond magnet composition. Rotate together. It is an important factor for the orientation of the anisotropic magnetic material that the cross-linking reaction is terminated and thermosetting is performed while the integral rotation is maintained, and the discharge port is reached.
That is, by rotating the inner die 50 and the bonded magnet composition integrally, it is possible to obtain a cylindrical bonded magnet in which each magnetic pole is oriented straight in the longitudinal direction.

  FIG. 4 is an explanatory diagram for explaining the orientation of the bonded magnet, and is a view observed by placing a magnet viewer on the inner peripheral side of the bonded magnet molded product. The magnetic pole is black (indicated by light ink in the figure), and the switching between the magnetic poles appears white. When the film is oriented straight in the longitudinal direction, the orientation angle θ in FIG. 4 is 0 °.

  In the present embodiment, the bonded magnet composition rotates with the inner die 50 while receiving resistance from the outer die 60. When the orientation magnet 70 is positioned on the inner side of the outer die end 90, for example, when x = 5 mm in FIG. 3, the orientation magnet 70 does not exist in the vicinity of the die discharge port, so that the bonded magnet composition is adsorbed. Therefore, the bonded magnet composition cannot rotate integrally with the inner die 50 due to the resistance with the outer die 60, and the molded product is twisted. The orientation angle θ in FIG. 4 of the bonded magnet molded product obtained at this time is about 30 °, and the magnetic poles are twisted with respect to the longitudinal direction, and a desired bonded magnet molded product is obtained. Disappear.

  As described above, in this embodiment, the orientation magnet 70 is disposed up to the outer die end portion 90 in order to complete the crosslinking reaction and cure while maintaining the integral rotation. FIG. 5 illustrates an example that satisfies such an arrangement.

  In FIG. 5A, the end portion of the orientation magnet 70 and the outer die end portion 90 are flush with each other on the discharge port side (extrusion direction). Compared to the example of FIG. 1, the orientation magnet 70 is not exposed from the inner die 50 and is completely embedded in the inner die 50, and the outermost portion of the inner die 50 is the outer die 60 on the discharge side. It is formed so as to protrude from the outermost part. Thus, the orientation magnet 70 can be prevented from being cracked or chipped by being embedded in the inner die 50 without exposing the orientation magnet 70 to the outside.

  In FIG. 5B, the end portion of the orientation magnet 70 is disposed so as to protrude from the outer die end portion 90 on the discharge port side (extrusion direction). Thus, the orientation magnet 70 may be protruded.

  In FIG. 5C, the outer die 60 has a step on the discharge port side (extrusion direction), and has the outer die outermost portion 92 on the discharge port side with respect to the outer die end portion 90. Further, the entire orientation magnet 70 is embedded in the inner die 50, and the inner die outermost portion 94 and the outer die outermost portion 92 are arranged to be flush with each other.

  In FIG. 5D, the outer die 60 is tapered on the discharge port side (extrusion direction), and the outer die 60 is located closer to the discharge port side than the outer die end 90 as in the example of FIG. It has an exterior 92. Further, the entire orientation magnet 70 is embedded in the inner die 50, and the inner die outermost portion 94 and the outer die outermost portion 92 are arranged to be flush with each other.

  As illustrated above, if the orientation magnet 70 protrudes more toward the discharge port than the outer die end portion 90, twisting does not occur.

  The extrusion molding method as in the present embodiment is a continuous type with respect to a batch type of injection molding or compression molding, which is another molding method generally used as a molding method for bonded magnets. Excellent. Furthermore, since it can shape | mold continuously, the shaping | molding of the long product which was difficult by injection molding and compression molding becomes easy.

Hereafter, each structure which can be used for this embodiment is demonstrated in detail.
(Orientation magnet 70)
The material of the magnet used for the permanent magnet for orientation is preferably one with Br of 1T or more, and for example, an Nd—Fe—B based sintered magnet or an Sm—Co based sintered magnet can be used. When a magnet with a large magnetic force is used, the orientation magnetic field becomes stronger and the surface magnetic flux density of the bonded magnet can be increased.
In addition, the bonded magnet obtained by extrusion molding as described above is preferably subjected to secondary curing.
Further, if necessary, a magnetizing step may be performed. By performing the magnetization, the surface magnetic flux density becomes higher.

(Anisotropic magnetic material)
Examples of the anisotropic magnetic material used in the present invention include ferrite, Sm—Co, Nd—Fe—B, and Sm—Fe—N. It is preferably in powder form.
Ferrites are the most popular because they have a long history and are inexpensive, but they have a lower magnetic force than rare earths, and if the molded product is smaller, the magnetic force may be insufficient. Therefore, when it is necessary to produce a bond magnet having a strong magnetic force, it is preferable to use rare earth magnetic powders of Sm—Co, Nd—Fe—B, and Sm—Fe—N. This is because rare earth-based anisotropic magnetic powders are very easily aligned in magnetization direction by a magnetic field applied during orientation, and as a result, the magnetic force of the bond magnet is increased. Moreover, since the particle diameter is about 3 μm and it is a substantially spherical shape, the extrusion moldability is excellent, and therefore, the Sm—Fe—N system is preferable.
The above magnetic materials can be used alone or as a mixture of two or more. Moreover, you may perform an oxidation resistance process and a coupling process as needed.

(Thermosetting resin)
In the present invention, a thermosetting resin is used as the resin. Thermosetting resins are accompanied by a crosslinking reaction. Prior to molding, the thermosetting resin as a monomer is changed into a polymer by a three-dimensional crosslinking reaction during molding or subsequent heating, ultraviolet irradiation, or the like. The thermosetting resin that has undergone crosslinking reaction is suitable for use at high temperatures because it is less susceptible to deformation due to melting of the resin during heating and low molecular component volatilization.

  The thermosetting resin that can be used in the present invention is not particularly limited, and various thermosetting resins can be used. For example, epoxy resin, phenol resin, unsaturated polyester resin, urea resin, melamine resin, polyimide Resins, allyl resins and the like can be used.

  The epoxy resin that can be used in the present invention is not particularly limited, for example, glycidyl ether type epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, alcohol type epoxy resin, Various epoxy resins such as glycidylamine type epoxy resins such as aromatic amine type epoxy resins and aminophenol type epoxy resins, glycidyl ester type epoxy resins such as hydrophthalic acid type epoxy resins and dimer acid type epoxy resins, and alicyclic epoxy resins In addition, modified epoxy resins such as rubber-modified epoxy resins, brominated epoxy resins, and urethane-modified epoxy resins can be used.

  The curing agent for the epoxy resin is not particularly limited and conventionally known ones can be widely used, and examples thereof include primary amines, secondary amines, acid anhydrides, phenol resins, and the like. It may be used in a mixture of two or more. In particular, those using a phenolic resin as a curing agent are preferable because they are excellent in heat resistance and water resistance.

  The curing accelerator for the epoxy resin is not particularly limited, and phosphine compounds, phosphonium salts, imidazoles, imidazolium salts, amines, diazabicyclo compounds, diazabicyclo compounds tetraphenylborate, phenol salts, phenol novolacs. Salt, 2-ethylhexanoate and the like. In these curing accelerators, it is preferable to use an imidazole curing accelerator from the viewpoint that the curing reaction during the retention of the extrusion screw is suppressed and the stable moldability is improved.

  The phenolic resin that can be used in the present invention is not particularly limited, and conventionally known phenolic resins can be used. Examples thereof include composites with other materials modified with phenol, such as modified phenolic resins and phenol-modified melamine resins. Although it does not specifically limit as a hardening | curing agent of a novolak-type phenol resin, Amine-type hardening | curing agents, such as a hexamethylene tetramine, can be used conveniently.

  There is no restriction | limiting in particular as unsaturated polyester resin, Although a conventionally well-known thing can be used widely, The polyester resin which has 2 or more of unsaturated bonds per molecule, such as diallyl phthalate, diallyl malate, divinyl phthalate, is mentioned. be able to.

  The crosslinking agent for the unsaturated polyester resin is not particularly limited as long as it has a polymerizable double bond, and conventionally known ones can be widely used. For example, styrene, diallyl phthalate, methyl methacrylate , Vinyl monomers such as divinylbenzene, acrylamide, vinyltoluene, monochlorostyrene, acrylonitrile, triallyl isocyanurate, diallyl phthalate prepolymer, and the like.

  As the curing agent for the unsaturated polyester resin, a peroxide can be usually used, but t-butyl peroxy octoate, benzoyl peroxide, 1,1-di-t-butyl peroxy-3, 3, 5-trimethylcyclohexane, t-butylperoxyisopropyl carbonate, t-butylperoxybenzoate, dicumyl peroxide, di-t-butyl peroxide, lauroyl peroxide, di-t-butylperoxyisophthalate, 2,5 -Dimethylhexane, 2,5-dihydroperoxide, cumene hydroperoxide, methyl ethyl ketone peroxide, etc. can be used.

  Examples of urea resins include various urea resins that are cationic, nonionic, or anionic. The curing agent used for the curing reaction of the urea resin is not particularly limited. For example, an apparent curing agent composed of an acidic salt such as an inorganic acid, an organic acid, or acidic sodium sulfate; a carboxylic acid ester, an acid anhydride, or a chloride. Examples include latent curing agents such as salts of ammonium and ammonium phosphate. Among these, a latent curing agent is preferable from the viewpoint of shelf life.

  Examples of the melamine resin include a urea-melamine resin which is a modified urea resin in addition to the melamine resin alone.

  Examples of the polyimide resin include a maleimide-modified epoxy resin in addition to a polyimide resin obtained by a reaction of tetracarboxylic acid or its anhydride and diamine.

  The allyl resin is obtained by polymerization and curing reaction of diallyl phthalate monomer. Examples of the diallyl phthalate monomer include an ortho isomer, an iso isomer, and a tele isomer. Although it does not specifically limit as a hardening accelerator, For example, combined use of t-butyl perbenzoate and di-t-butyl peroxide is suitable.

  These thermosetting resins can be used alone or in admixture of two or more.

  Although the blending ratio of the magnetic material and the resin depends on the type of the resin, it is desirable that the ratio of the magnetic material to the entire bonded magnet composition is 45 to 65 Vol%. Further, an antioxidant, a lubricant and the like can be further mixed.

  Examples according to the present invention will be described in detail below. Needless to say, the present invention is not limited to the following examples.

<Example 1>
(Preparation of magnetic material)
An anisotropic Sm—Fe—N magnetic material (average particle diameter of 3 μm) is used as the magnetic material.

(Preparation of magnet composition)
A thermosetting resin (main agent) such as an epoxy resin, a curing agent, and a small amount of additives such as a curing accelerator as necessary were added to the Sm-Fe-N magnetic material, and then mixed sufficiently with a mixer. The obtained mixed powder was kneaded in a temperature range where the curing reaction hardly progressed using a biaxial kneader, cooled, and then cut into an appropriate size to obtain a bonded magnet composition.

(Extrusion molding)
FIG. 1 is a diagram showing an extrusion molding apparatus used in the first embodiment. The inner diameter of the outer die is 19 mm, and the outer diameter of the inner die is 17 mm. As shown in FIG. 2, the magnet for orientation 70 was formed into a cylindrical shape by assembling six magnet pieces. The assembled magnet for orientation generates a magnetic force of 6 poles on the outer peripheral side. This was embedded in the inner die. At this time, the distance x between the orientation magnet and the outer die shown in FIG. 3 is 0 mm, and the end portion of the orientation magnet 70 and the outer die end portion 90 are flush with each other. The temperature was set at 110 ° C. for the screw part 1 and 180 ° C. for the mold part 2. Thus, an anisotropic cylindrical bonded magnet having an outer diameter of 19 mm, an inner diameter of 17 mm, a length of 1000 mm, and an inner circumference of 12 poles was obtained. It cut | disconnected to length 20mm using the cutting machine.

(Magnetization process)
The obtained molded product is magnetized by a magnetizing yoke. The magnetization conditions are a capacitance of 1000 μF and a voltage of 2.5 KV, and the current flowing at that time is 18.0 KA.

(Evaluation)
The orientation angle was evaluated by dividing the bonded magnet molded product in half and placing a magnet viewer on the inner peripheral surface of the bonded magnet molded product. This is shown in FIG. The orientation angle θ at this time was 0 °.
The surface magnetic flux density was evaluated by measuring the surface magnetic flux density on the inner periphery of the cylindrical bonded magnet with a magnet analyzer. The measurement was performed by fixing the cylindrical bonded magnet to the 360 ° rotation stage of the magnet analyzer, bringing the probe into contact with the inner peripheral side surface of the cylindrical bonded magnet, and rotating the stage by 360 °. The surface magnetic flux density at this time was 2300G.

<Comparative Example 1>
In extrusion molding, a mold having a distance x shown in FIG. 3 of 5 mm, that is, a mold in which an outer die end 90 protrudes to the discharge port side (extrusion direction) from the end of the orientation magnet 70 is used. An anisotropic cylindrical bonded magnet was produced in the same manner as in Example 1 except that. As shown in FIG. 7, in the evaluation of the orientation angle, the orientation angle θ was 30 °. The surface magnetic flux density was 1700G.

<Comparative Example 2>
In extrusion molding, a mold having a distance x of 10 mm shown in FIG. 3, that is, a mold in which an outer die end 90 protrudes toward the discharge port side (extrusion direction) from the end of the orientation magnet 70 is used. The same method as in Example 1 was used except that. As shown in FIG. 8, in the evaluation of the orientation angle, the orientation angle θ was 70 °. The surface magnetic flux density was 1300G.

  Table 1 shows the orientation angle and surface magnetic flux density of Examples and Comparative Examples.

  As can be seen from Table 1, in Example 1, the orientation is not disturbed as in the comparative example, and the surface magnetic flux density is stronger than in the comparative example.

  The present invention can be used for an outer rotor motor such as a hard disk drive or a spindle motor for optical media.

DESCRIPTION OF SYMBOLS 1 Screw part 2 Mold part 30 Cylinder 40 Screw 50 Inner die 60 Outer die 70 Orientation magnet 80 Hopper 90 Outer die end part 92 Outer die outermost part 94 Inner die outermost part 96 Spider

Claims (8)

An extrusion apparatus for extruding a bonded magnet composition having an anisotropic magnetic material and a thermosetting resin,
An outer die having a through hole for molding the outer periphery of the cylindrical bonded magnet;
An inner die arranged in the through hole and for molding the inner periphery of the bond magnet;
A screw for extruding the material of the bond magnet,
The inner die is connected to the screw and is rotatable.
An orientation magnet is embedded in the inner die,
In the extrusion direction of the extrusion molding apparatus, the orientation magnet is disposed up to the end of the outer die.   The extrusion molding apparatus according to claim 1, wherein the orientation magnet end portion and the outer die end portion are arranged flush with each other in the extrusion direction of the extrusion molding device.   2. The extrusion molding apparatus according to claim 1, wherein in the extrusion direction of the extrusion molding apparatus, the magnet for orientation is arranged so as to protrude from an end portion of the outer die.   The extrusion molding apparatus according to any one of claims 1 to 3, wherein the orientation magnet is exposed from the inner die.   The extrusion according to any one of claims 1 to 4, wherein the outermost part of the inner die and the outermost part of the outer die are arranged flush with each other in the extrusion direction of the extrusion molding apparatus. Molding equipment. A method of extruding a mixed composition of an anisotropic magnetic material and a thermosetting resin with a screw type extruder,
Using an extrusion molding apparatus in which an orientation magnet is embedded in an inner die that is connected to the screw and is rotatable, and the orientation magnet is arranged up to the end of the outer die in the extrusion direction of the extrusion molding apparatus. A method for extruding a cylindrical bonded magnet, wherein the inner die and the composition are molded by thermosetting while integrally rotating.   The cylindrical anisotropic bonded magnet extrusion method according to claim 6, wherein the anisotropic magnetic material is Sm—Fe—N based magnetic powder.   The method for extruding a cylindrical bonded magnet according to claim 6 or 7, wherein the thermosetting resin is an epoxy resin.

Images