JP2005312103A - Process for producing dust core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a dust core exhibiting excellent dimensional accuracy and desired performance. <P>SOLUTION: The process for producing a dust core comprises a step for forming a plurality of teeth portions 12 having a shank 13 by pressing soft magnetic powder, a step for attaching a coil 15 by applying it over each shank 13 of the plurality of teeth portions 12, and a step for arranging the plurality of teeth portions 12 applied with the coil 15 in the recess 53m of a die 51, filling the die 51 with soft magnetic powder 35 and pressing them to form a molding. The molding has a yoke portion extending annularly, and the plurality of teeth portions 12 bonded to the yoke portion at a predetermined interval along the circumferential direction of the yoke portion such that the shank 13 projects in the radial direction of the yoke portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention generally relates to a method for manufacturing a dust core, and more particularly, to a method for manufacturing a dust core used as a stator core of an electric motor.

  Conventionally, a magnetic core used as a stator core of an electric motor or the like is produced by laminating a plurality of electromagnetic steel sheet materials and winding a coil around the laminated material. However, in this case, there is a need for winding the coil, and the coil comes into contact with the flash of the electromagnetic steel sheet material, and the coil may be damaged. Moreover, the corner part of the part which winds a coil cannot be curved on the characteristic of an electromagnetic steel plate material. For this reason, there arises a problem that the coil is wound in a state having a large overhang depending on the wire diameter of the coil.

  Therefore, in order to solve such a problem, a magnetic core used as a stator core of an electric motor or the like is manufactured from a molded body of soft magnetic powder. In this regard, for example, Japanese Patent Application Publication No. 2003-507991 discloses a method of manufacturing an armature segment of an electric machine (Patent Document 1).

  11 and 12 are cross-sectional views showing the steps of the method of manufacturing the armature segment disclosed in Patent Document 1. Referring to FIG. 11, a coil 101 is manufactured by winding a copper wire a plurality of times in a spiral shape, and the coil 101 is pre-compressed. Next, the coil 101 is installed in the molding recess of the die 105. Referring to FIG. 12, ferromagnetic particles are filled in the molding recess where the coil 101 is installed, and the ferromagnetic particles are pressure-molded together with the coil 101. Thereby, the armature segment 106 including the coil 101 and the core portion 107 is formed. Thereafter, the armature segments 106 are assembled to complete the armature.

Japanese Patent Application Laid-Open No. 56-58764 discloses a motor with a core in which a coil wire is completely embedded in a fine powder of a soft magnetic material (Patent Document 2).
Japanese translation of PCT publication No. 2003-507991 JP-A-56-58764

  However, as disclosed in Patent Document 1, when the coil 101 and the ferromagnetic particles are simultaneously pressure-molded, the compression force at the time of pressure molding is directly applied to the coil 101, so that the coil 101 is deformed. There is a risk of damage. In addition, when the coil 101 is placed on the die 105 or during pressure molding, the coil 101 and the surface of the molding recess or the ferromagnetic particles are strongly rubbed, so that the insulator provided in the coil 101 may be damaged.

  Furthermore, in the manufacturing method disclosed in Patent Document 1, a plurality of armature segments 106 are first manufactured, and then the armature segments 106 are assembled to complete the armature. For this reason, the dimensional accuracy of the completed armature may deteriorate due to individual shape errors of the armature segments 106 and errors during assembly. In these cases, the armature cannot sufficiently exhibit the required performance.

  Moreover, in the motor with a core disclosed in Patent Document 2, since the coil wire is embedded in the fine powder of the soft magnetic material, the formed magnetic circuit is a closed circuit. In this case, there is no problem as long as it is used for an electronic component such as an inductor. However, when it is used as a motor, deterioration of magnetic characteristics becomes a problem.

  Accordingly, an object of the present invention is to solve the above-mentioned problems, and to provide a method for manufacturing a dust core that has excellent dimensional accuracy and exhibits desired performance.

  The method of manufacturing a powder magnetic core according to the present invention includes a step of forming a plurality of tooth portions having a shaft portion by press-molding soft magnetic powder, and a coil on each shaft portion of the plurality of tooth portions. Inserting and assembling the coil, and arranging a plurality of teeth portions assembled with the coil in the mold, filling the mold with soft magnetic powder, and forming these by pressure molding With. The molded body includes a yoke portion extending in an annular shape and a plurality of teeth joined to the yoke portion at predetermined intervals along the circumferential direction of the yoke portion so that the shaft portion protrudes in the radial direction of the yoke portion. Part.

  According to the method of manufacturing a powder magnetic core configured as described above, first, a soft magnetic powder is pressure-molded to form a tooth portion, and then a coil is assembled to the obtained tooth portion. For this reason, the coil is not deformed or damaged by pressure molding when forming the tooth portion. Thereby, a coil is protected appropriately and a dust core can exhibit desired performance. In addition, a plurality of teeth portions assembled with a coil are positioned in a concave portion of a mold, and a set with soft magnetic powder is formed, and a molded body composed of a yoke portion and a plurality of teeth portions is formed by pressure molding these It is formed integrally. For this reason, a molded object can be made into the shape according to a metal mold | die shape, and the outstanding dimensional accuracy can be implement | achieved.

  Further, the shape of the shaft portion can be set to an arbitrary shape considering the assembly of the coil during the process of forming the tooth portion. Thereby, a coil can be assembled | attached to the axial part of a teeth part in a desired state. Moreover, since the molded object produced by pressure molding contains the several teeth part separately shape | molded previously, the intensity | strength of a molded object can be improved.

  In addition, the mold has a pair of punch portions that are arranged to face each other and relatively move in a direction in which they are close to each other during pressure molding. Preferably, in the step of forming the molded body, the plurality of teeth portions are arranged in the mold so that the coil assembled to each of the plurality of tooth portions is positioned so as to be shifted from the region sandwiched between the pair of punch portions. The process of carrying out is included. According to the method for manufacturing a powder magnetic core configured as described above, the compression force from the pair of punch portions is not directly applied to the coil during the step of forming the formed body. For this reason, it can prevent that a coil deform | transforms or breaks at the time of the pressure molding at the time of forming a molded object. Here, the relative movement of the pair of punch portions includes a case where the pair of punch portions move close to each other and a case where one punch portion is fixed and the other punch portion is moved close to each other.

  In addition, the mold has a pair of punch portions that are arranged to face each other and relatively move in a direction in which they are close to each other during pressure molding. Preferably, in the step of forming the formed body, the plurality of teeth portions are arranged such that the other portions of the teeth portions excluding the joint portions with the yoke portions are shifted from the region sandwiched between the pair of punch portions. Including a step of placing the mold. According to the method of manufacturing a powder magnetic core configured in this way, during the step of forming the formed body, the compressive force from the pair of punch portions is directly applied to other portions of the teeth portion excluding the joint portion with the yoke portion. There is no load. For this reason, it can suppress that an internal stress and distortion are introduce | transduced into the other part of a teeth part at the time of the pressure molding at the time of forming a molded object.

  Further, the shaft portion has an end surface at a tip protruding in the radial direction of the yoke portion. The mold has first and second divided dies that, when combined with each other, define a recess of the mold in which a plurality of tooth portions are disposed. In the method of manufacturing a dust core, preferably, in the step of forming the molded body, the plurality of teeth portions are positioned on the first split die so that the end face comes into contact with the inner wall of the recess, and the second split die Combining with the first split die. According to the method of manufacturing a powder magnetic core configured as described above, the teeth in the radial direction of the yoke portion can be obtained by arranging the teeth portion in the mold in a state where the end surface of the shaft portion is in contact with the inner wall of the recess. The position of the part can be accurately determined. As a result, it is possible to produce a molded body having further excellent dimensional accuracy.

  Preferably, the first and second divided dies include side surfaces that define a space filled with soft magnetic powder. According to the method of manufacturing a powder magnetic core configured as described above, a space filled with soft magnetic powder can be formed by combining the first and second divided dies. For this reason, it is possible to simultaneously achieve the position fixing of the plurality of teeth portions with respect to the mold and the securing of the filling height of the soft magnetic powder necessary for forming the yoke portions.

  Preferably, the step of assembling the coil includes a step of interposing a lubricating member between the tooth portion and the coil. According to the method for manufacturing a powder magnetic core configured as described above, it is possible to improve the lubricity between the tooth portion and the coil and prevent them from being damaged during the process of assembling the coil. In particular, it is possible to prevent the insulating coating formed on the surface of the coil from being damaged. Even if an insulating paper (ceramic sheet, paper, resin sheet or the like) is interposed as the lubricating member, it is effective.

  Preferably, the step of forming the molded body includes a step of arranging a plurality of teeth portions and soft magnetic powder in the mold by interposing a lubricating member between the coil assembled in the teeth portion and the die. Including. According to the method of manufacturing a powder magnetic core configured in this way, the lubricity between the coil and the mold is improved, and the coil is damaged when the teeth portion assembled with the coil is placed in the mold. Can be prevented. In particular, it is possible to prevent the insulating coating formed on the surface of the coil from being damaged. Even if an insulating paper (ceramic sheet, paper, resin sheet or the like) is interposed as the lubricating member, it is effective.

  Preferably, the step of forming the molded body includes a step of pressure-molding the plurality of teeth portions and the soft magnetic powder by interposing a lubricating member between the coil assembled in the teeth portion and the soft magnetic powder. Including. According to the method of manufacturing a powder magnetic core configured as described above, the lubricity between the coil and the soft magnetic powder can be improved, and the coil can be prevented from being damaged during the pressure molding when the molded body is formed. . In particular, it is possible to prevent the insulating coating formed on the surface of the coil from being damaged. Even if an insulating paper (ceramic sheet, paper, resin sheet or the like) is interposed as the lubricating member, it is effective.

  As described above, according to the present invention, it is possible to provide a method of manufacturing a dust core that has excellent dimensional accuracy and exhibits desired performance.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a front view of an electric motor provided with a stator core manufactured in an embodiment of the present invention.

  With reference to FIG. 1, the electric motor 1 includes a ring-shaped stator core 10 and a columnar rotor core 2 disposed on the inner peripheral side of the stator core 10. The rotor core 2 has a rotation shaft 4 at the center. As the rotor core 2 rotates about the rotation shaft 4, a rotary motion is output from the electric motor 1. Permanent magnets 3 are embedded in the periphery of the rotor core 2 at predetermined angles.

  The stator core 10 is formed by joining a plurality of soft magnetic particles to each other. The stator core 10 includes a yoke portion 11 that extends in an annular shape and a plurality of teeth portions 12 that protrude from the yoke portion 11 to the inner peripheral side of the yoke portion 11. The plurality of tooth portions 12 are provided at predetermined angles at intervals.

  The teeth portion 12 is joined to the yoke portion 11 and includes a shaft portion 13 extending in the radial direction of the yoke portion 11 and a flange portion 14 provided at the tip of the shaft portion 13 and facing the outer peripheral surface of the rotor core 2. Have. The flange portion 14 is formed with a wider width in the circumferential direction of the yoke portion 11 than the shaft portion 13. Around the shaft portion 13, a coil 15 formed by winding a conductive wire in a spiral shape is provided. The coil 15 is disposed so as to be sandwiched between the yoke portion 11 and the flange portion 14, and thereby the position with respect to the tooth portion 12 is fixed.

  FIG. 2 is an enlarged schematic view showing the surface of the stator core in FIG. With reference to FIG. 2, the plurality of soft magnetic particles 23 constituting the stator core 10 include metal magnetic particles 21 and an insulating coating 22 surrounding the surface of the metal magnetic particles 21. An organic substance 24 is interposed between the plurality of soft magnetic particles 23. Each of the soft magnetic particles 23 is joined by an organic substance 24 or joined by engaging unevenness of the soft magnetic particles 23.

  The metal magnetic particles 21 are, for example, iron (Fe), iron (Fe) -silicon (Si) alloy, iron (Fe) -nitrogen (N) alloy, iron (Fe) -nickel (Ni) alloy, iron (Fe) -carbon (C) alloy, iron (Fe) -boron (B) alloy, iron (Fe) -cobalt (Co) alloy, iron (Fe) -phosphorus (P) alloy, iron (Fe ) -Nickel (Ni) -cobalt (Co) alloy and iron (Fe) -aluminum (Al) -silicon (Si) alloy. The metal magnetic particles 21 may be a single metal or an alloy.

  The insulating coating 22 is formed, for example, by subjecting the metal magnetic particles 21 to phosphoric acid treatment. Preferably, the insulating coating 22 contains an oxide. As the insulating coating 22 containing this oxide, in addition to iron phosphate containing phosphorus and iron, manganese phosphate, zinc phosphate, calcium phosphate, aluminum phosphate, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, etc. The oxide insulator can be used. The insulating coating 22 may be formed in one layer as shown in the figure, or may be formed in multiple layers.

  The insulating coating 22 functions as an insulating layer between the metal magnetic particles 21. By covering the metal magnetic particles 21 with the insulating coating 22, the electrical resistivity ρ of the stator core 10 can be increased. Thereby, it can suppress that an eddy current flows between the metal magnetic particles 21, and can reduce the iron loss resulting from an eddy current.

  Examples of the organic substance 24 include thermoplastic resins such as thermoplastic polyimide, thermoplastic polyamide, thermoplastic polyamideimide, polyphenylene sulfide, polyamideimide, polyethersulfone, polyetherimide or polyetheretherketone, wholly aromatic polyester, wholly aromatic. Non-thermoplastic resins such as group polyimide or high molecular weight polyethylene and higher fatty acids such as zinc stearate, lithium stearate, calcium stearate, lithium palmitate, calcium palmitate, lithium oleate or calcium oleate can be used. Moreover, these can also be mixed and used for each other. High molecular weight polyethylene refers to polyethylene having a molecular weight of 100,000 or more.

  The organic material 24 firmly joins the plurality of soft magnetic particles 23 to improve the strength of the stator core 10. The organic substance 24 functions as a lubricant during pressure molding for obtaining the stator core 10. Thereby, the soft magnetic particles 23 are rubbed against each other to prevent the insulating coating 22 from being broken.

  FIG. 3 is a flowchart showing the steps of the stator core manufacturing method shown in FIG. 4 to 9 are explanatory views for explaining each step of the manufacturing method shown in FIG. Hereinafter, the manufacturing method of the dust core in the present embodiment will be described with reference to these drawings.

  Referring to FIG. 3, first, a teeth portion preforming step (S100) is performed. Referring to FIG. 4, soft magnetic powder 35 in which soft magnetic particles 23 and organic substance 24 shown in FIG. 2 are mixed is placed in a mold, and pressure-molded at a pressure of, for example, 700 MPa to 1500 MPa. Thereby, the soft magnetic powder 35 is compressed, and the teeth part 12 which consists of the axial part 13 and the collar part 14 is produced. At this time, the atmosphere for pressure molding is preferably an inert gas atmosphere or a reduced pressure atmosphere. In this case, it is possible to suppress the soft magnetic powder 35 from being oxidized by oxygen in the atmosphere.

  Separately, the coil manufacturing step (S101) in FIG. The coil 15 is formed in a spiral shape using a conductive wire covered with an insulating film. The conducting wire is made of, for example, copper, and its diameter is about 0.3 mm to 3 mm. The insulating coating is made of, for example, a general enamel (gutter) and has a thickness of about 30 μm.

  When the coil 15 is described in more detail, the spiral shape in which the coil 15 is formed includes not only a circular shape when viewed from the axial direction but also an elliptical shape and a rectangular shape. It is. Further, the winding method of the conducting wire may be either aligned winding or random winding. 5A to 5C are perspective views showing various forms of coils. Referring to FIG. 5, for example, when a flat wire is used as the conducting wire, either an edgewise winding coil or a flatwise winding coil is used as shown in FIGS. 5A and 5B, respectively. You can also. In the case of the edgewise coil shown in FIG. 5 (A), the end of the conductor 26 is drawn out to the upper and lower ends of the coil. In the case of the flatwise winding coil shown in FIG. 5 (B), the rectangular conductor 27 is folded back, and the conductor 27 is wound with the folded position as the inner peripheral end, so that both ends of the conductor 27 are placed on the outer peripheral side. It can be pulled out. Furthermore, as shown in FIG. 5C, a random winding coil with a round wire 28 can be used. In this case, winding of the conducting wire 28 is easy and the terminal of the conducting wire 28 can be pulled out from a desired position.

  Next, the coil assembling step (S103) in FIG. 3 is performed. Referring to FIG. 6, the coil 15 is assembled to the tooth portion 12 by inserting the coil 15 through the shaft portion 13 of the tooth portion 12. Thereby, the teeth part unit 40 with which the coil 15 was assembled | attached is produced. At this time, before performing the coil assembling step (S103), a WAX molding step (S102) in FIG. 3 described below may be performed.

  Referring to FIG. 7, when performing the WAX molding step (S <b> 102), lubrication member 42 is provided on end surface 15 a that comes into contact with flange 14 when assembled to inner peripheral portion 15 c of coil 15 and teeth portion 12. . At this time, as the lubricating member 42, for example, a resin member, a wax, a ceramic sheet, paper, or a resin sheet can be used. Thereby, when inserting the coil 15 in the axial part 13 in a coil assembly | attachment process (S103), the slipperiness of the teeth part 12 and the coil 15 is improved. Thereby, it can prevent that the insulating film provided in the coil 15 is damaged. Further, in the WAX molding step (S102), the lubricating member 41 may be provided on the outer peripheral portion 15d of the coil 15, or the lubricating member 43 is provided on the end surface 15b of the coil 15 located on the side opposite to the end surface 15a. Also good.

  Next, the press molding step (S104) in FIG. 3 is performed. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. Referring to FIGS. 8 and 9, the mold 51 used in the press molding step (S104) is arranged with a gap between each other, and an outer die 52 that defines an annular space 54 in the gap. And an inner die 53. The mold 51 further includes an upper punch 55 and a lower punch 56 that are disposed to face each other with the annular space 54 interposed therebetween. The inner die 53 has a peripheral edge 53 n that faces the space 54. The peripheral edge 53n is formed with a recess 53m in which the tooth unit 40 is accommodated at predetermined intervals. The inner die 53 is constituted by inner divided dies 53a and 53b, and these divided dies are combined to form a recess 53m.

  First, the plurality of teeth unit 40 obtained in the coil assembling step (S103) is set in the recess 53m, and then the soft magnetic powder 35 similar to that used in the teeth portion pre-forming step (S100) It is put into a space 54 defined in the mold 51. To set the tooth unit 40, first, the tooth unit 40 is disposed on the inner split die 53a so that the end surface 12a of the tooth portion 12 abuts on the positioning portion 53y of the recess 53m, and then the upper portion of the inner split die 53a To the inner divided die 53b. At this time, when the inner divided die 53a and the inner divided die 53b are combined, a peripheral edge 53n of the inner die 53 that defines the space 54 is formed. Therefore, the position fixing of the tooth unit 40 and the formation of the space 54 filled with the soft magnetic powder 35 can be completed simultaneously by the combination of the inner division dies 53a and 53b.

  The teeth unit 40 is arranged in a direction in which the end face 15b of the coil 15 faces the space 54, and the soft magnetic powder 35 put into the space and the end face 15b of the coil 15 come into contact with each other. The teeth portion 12 is positioned so that the tip 13q of the shaft portion 13 protruding from the collar portion 14 is embedded in the soft magnetic powder 35.

  At this time, the coil 15 provided in the teeth unit 40 is completely accommodated in the recess 53m. Therefore, the coil 15 is arranged such that the end face 15b of the coil 15 and the peripheral edge 53n of the inner die 53 are flush with each other, or the end face 15b is positioned one step down from the peripheral edge 53n. Moreover, the teeth part 12 is arrange | positioned in the state in which the whole collar part 14 and the other part 13p of the axial part 13 except the above-mentioned part 13q were accommodated in the recessed part 53m. That is, the teeth unit 40 is disposed at a position displaced from the annular space 54 except for the portion 13q of the shaft portion 13.

  Further, the tooth unit 40 is positioned with the end surface 12a of the tooth portion 12 in contact with the positioning portion 53y of the concave portion 53m in a state where the concave portion 53m is set. Thereby, the positioning accuracy in the radial direction of the yoke portion 11 of the tooth portion unit 40 is ensured, and when it becomes a stator core, it is possible to prevent interference with the rotor core or an excessively large gap.

  When the WAX molding step (S102) is performed in the previous step and the lubricating member 41 is provided on the outer peripheral portion 15d of the coil 15, when the teeth unit 40 is set in the concave portion 53m, the coil 15 and the concave portion 53m It is possible to prevent the surface from rubbing strongly. Thereby, it can prevent that the insulating film provided in the coil 15 is damaged.

  Next, the upper punch 55 is moved toward the lower punch 56, and the soft magnetic powder 35 and the plurality of teeth unit 40 are pressure-molded at a pressure of, for example, 700 MPa to 1500 MPa. As a result, the soft magnetic powder 35 is compressed to produce the annularly extending yoke portion 11, and a plurality of teeth unit 40 is joined to the yoke portion 11. Thereby, the shape of the stator core 10 shown in FIG. 1 is completed.

  At this time, the atmosphere for pressure molding is preferably an inert gas atmosphere or a reduced pressure atmosphere, as in the teeth portion preforming step (S100). Further, when the WAX molding step (S102) is performed in the previous step and the lubricating member 43 is provided on the end surface 15b of the coil 15, the coil 15 and the soft magnetic powder 35 rub against each other strongly during the above-described pressure molding. Can be prevented. Thereby, it can prevent that the insulating film provided in the coil 15 is damaged.

  The teeth unit 40 is disposed at a position displaced from the annular space 54 except for the portion 13q of the shaft portion 13. For this reason, the compression force at the time of pressure molding generated by the movement of the upper punch 55 is not directly applied to the teeth portion 12 and the coil 15. Thereby, it can suppress that distortion and an internal stress are introduce | transduced into the inside of the teeth part 12, and it can prevent that the coil 15 deform | transforms or is damaged.

  Next, the stator core 10 is taken out from the mold 51, and the WAX removing step (S105) shown in FIG. 3 is performed. Finally, the annealing step (S106) shown in FIG. 3 is performed. At this time, the stator core 10 obtained in the previous step is less than the lower one of the thermal decomposition temperature of the insulating coating 22 provided on the soft magnetic powder 35 and the thermal decomposition temperature of the insulating coating provided on the coil 15. Heat treatment is performed. For example, when the insulating coating 22 provided on the soft magnetic powder 35 and the insulating coating provided on the coil 15 are respectively formed from a phosphoric acid coating and enamel, the thermal decomposition temperature of the enamel is less than 180 ° C. Heat treatment is performed for 1 hour or more at a temperature.

  By this heat treatment, internal stress and strain existing in the stator core 10 can be relaxed without deteriorating the insulating coating provided on either the soft magnetic powder 35 or the coil 15. Thereby, the magnetic characteristic of the stator core 10 can be improved. Through the steps described above, the stator core 10 shown in FIG. 1 is completed.

  The method for manufacturing a powder magnetic core according to the embodiment of the present invention includes a step (S100) of forming a plurality of teeth portions 12 having a shaft portion 13 by press-molding soft magnetic powder 35, and a plurality of teeth portions. After the step of inserting the coil 15 into each shaft portion 13 of 12 and assembling the coil 15 (S103) and the step of assembling the coil (S103), the plurality of teeth portions 12 are disposed in the concave portion 53m of the mold 51. And a step (S104) of forming a molded body by filling the mold 51 with the soft magnetic powder 35 and press-molding them. The molded body is joined to the yoke portion 11 at predetermined intervals along the circumferential direction of the yoke portion 11 such that the annularly extending yoke portion 11 and the shaft portion 13 protrude in the radial direction of the yoke portion 11. And a plurality of teeth portions 12.

  According to the method for manufacturing a powder magnetic core configured as described above, first, the teeth portion 12 is manufactured by performing the teeth portion preforming step (S100), and the coil 15 that has been separately prepared in the teeth portion 12 is prepared. It is assembled. For this reason, the coil 15 is not damaged in the teeth portion preforming step (S100). In the present embodiment, the stator core 10 is integrally formed in the press molding step (S104). For this reason, the stator core 10 having a shape conforming to the shape of the mold 51 can be realized. Thereby, compared with the case where the components which comprise the stator core 10 are formed first, and the components are further combined and the stator core 10 is produced, the dimensional accuracy of the stator core 10 can be improved.

  In addition, you may implement the process (S107) of heat-treating the teeth part 12 at the temperature below the thermal decomposition temperature of the insulating film 22 provided in the soft magnetic particle 23 before a coil assembly | attachment process (S103). The yoke portion 11 is preferably manufactured integrally from the viewpoint of improving the dimensional accuracy. However, the yoke portion 11 may be divided into a minimum number in consideration of the press capability of the mold. In this case, when assembling the plurality of yoke portions 11 formed in a divided manner, shrink fitting may be used, or processing may be performed after assembly in order to improve dimensional accuracy.

  FIG. 10 is a front view showing a modification of the electric motor shown in FIG. In the drawing, a part of the electric motor is shown. In addition, compared with the electric motor 1 shown in FIG. 1, the same reference number is attached | subjected to the member which is the same or it corresponds.

  Referring to FIG. 10, in electric motor 61 in the present modification, ring-shaped rotor core 2 is arranged on the outer peripheral side of stator core 10. The stator core 10 includes a yoke portion 11 that extends in an annular shape and a plurality of teeth portions 12 that protrude from the yoke portion 11 to the outer peripheral side of the yoke portion 11. The stator core 10 shown in FIG. 10 can also be manufactured by using the method for manufacturing a dust core in the present embodiment. In this case, the same effect as described above can be obtained.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a front view of the electric motor provided with the stator core produced in embodiment of this invention. It is the schematic diagram which expanded and showed the surface of the stator core in FIG. It is a flowchart which shows the process of the manufacturing method of the stator core shown in FIG. It is explanatory drawing for demonstrating the teeth part preforming process (S100) of the manufacturing method shown in FIG. It is a perspective view which shows the various forms of a coil, (A) shows an edgewise winding coil, (B) shows a flatwise winding coil, (C) shows a random winding coil. It is explanatory drawing for demonstrating the coil assembly | attachment process (S103) of the manufacturing method shown in FIG. It is explanatory drawing for demonstrating the WAX mold process (S102) of the manufacturing method shown in FIG. It is explanatory drawing for demonstrating the press molding process (S104) of the manufacturing method shown in FIG. It is sectional drawing along the IX-IX line in FIG. It is a front view which shows the modification of the electric motor shown in FIG. It is sectional drawing which shows the 1st process of the method of manufacturing the armature segment disclosed by patent document 1. FIG. It is sectional drawing which shows the 2nd process of the method of manufacturing the armature segment disclosed by patent document 1. FIG.

Explanation of symbols

  10 stator core, 11 yoke portion, 12 teeth portion, 13 shaft portion, 13p, 13q portion, 15 coil, 35 soft magnetic powder, 51 mold, 54 space, 55 upper punch, 56 lower punch.

Claims (8)

A step of forming a plurality of teeth portions having a shaft portion by press-molding soft magnetic powder;
Inserting a coil through the shaft portion of each of the plurality of tooth portions, and assembling the coil; and
The plurality of teeth portions assembled with the coils are arranged in a mold, and soft magnetic powder is filled in the mold, and these are pressure-molded to form an annularly extending yoke portion and the shaft Forming a molded body having the plurality of tooth portions joined to the yoke portion at predetermined intervals along the circumferential direction of the yoke portion such that the portion protrudes in the radial direction of the yoke portion; A method for producing a powder magnetic core. The mold has a pair of punch portions that are arranged to face each other and relatively move in a direction in which they are close to each other at the time of pressure molding,
The step of forming the molded body includes the step of disposing the plurality of teeth portions in the mold so that the coil assembled to each of the plurality of tooth portions is positioned out of a region sandwiched between the pair of punch portions. The manufacturing method of the powder magnetic core of Claim 1 including the process arrange | positioned. The mold has a pair of punch portions that are arranged to face each other and relatively move in a direction in which they are close to each other at the time of pressure molding,
The step of forming the molded body includes the step of forming the plurality of teeth so that other portions of the teeth portion excluding the joint portion with the yoke portion are positioned away from the region sandwiched between the pair of punch portions. The manufacturing method of the powder magnetic core of Claim 1 or 2 including the process of arrange | positioning a part to the said metal mold | die. The shaft portion has an end surface at a tip protruding in a radial direction of the yoke portion,
The mold has first and second divided dies that define a recess of the mold in which the plurality of tooth portions are arranged by being combined with each other;
In the step of forming the molded body, the plurality of teeth portions are positioned on the first divided die so that the end surface is in contact with the inner wall of the recess, and the second divided die is moved to the first divided die. The manufacturing method of the powder magnetic core of any one of Claim 1 to 3 including the process combined with a division | segmentation die | dye.   5. The method of manufacturing a dust core according to claim 4, wherein the first and second divided dies include a side surface that defines a space filled with soft magnetic powder.   The method of manufacturing a dust core according to any one of claims 1 to 5, wherein the step of assembling the coil includes a step of interposing a lubricating member between the tooth portion and the coil.   The step of forming the molded body includes a step of disposing a plurality of teeth portions and soft magnetic powder in a die by interposing a lubricating member between the coil assembled to the teeth portion and the die. The manufacturing method of the powder magnetic core of any one of Claim 1 to 6 containing.   The step of forming the molded body includes a step of pressure forming the plurality of teeth portions and the soft magnetic powder by interposing a lubricating member between the coil assembled to the teeth portion and the soft magnetic powder. The manufacturing method of the powder magnetic core of any one of Claim 1 to 7.

Images