JP2017048439A - Manufacturing method for coil for armature, manufacturing method for armature and manufacturing method for electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a coil for an armature capable of manufacturing the coil for the armature having a high degree of a shape freedom and exhibiting excellent characteristics, a manufacturing method for the armature capable of manufacturing the armature capable of realizing an electric motor having high efficiency, and a manufacturing method for the electric motor having the high efficiency.SOLUTION: A manufacturing method for a coil for an armature includes the steps of: molding metallic powder 81 having conductivity by utilizing a coil molding die 82 constituted of an organic material and obtaining a coil compact 83; and heating the coil compact 83 together with the coil molding die 82, eliminating the coil molding die 82 while sintering the coil compact 83, and obtaining the coil.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a method for manufacturing an armature coil, a method for manufacturing an armature, and a method for manufacturing an electric machine.

  Electric machines such as an electric motor (motor), an electric generator (generator), or an electric generator (motor generator) having both functions are used in many devices such as electric vehicles and hybrid vehicles.

  Such an electric machine includes a cylindrical stator (stator) and a rotor (rotor) that is rotatably provided inside the stator. Magnetic flux is supplied by the stator, and this magnetic flux acts on the rotor to generate electromagnetic force and induced electromotive force. In this case, the stator is a field element and the rotor is an armature.

  The armature includes a cored coil including a core and a coil. Among these, as a coil, the coil | winding formed by winding conducting wire is used (for example, refer patent document 1).

  On the other hand, as the core, a laminated core configured by laminating a plurality of electromagnetic steel plates is known (see, for example, Patent Document 1). Each electromagnetic steel plate is made of a soft magnetic material, and its surface is electrically insulated. Thereby, the eddy current which flows through a core can be suppressed and the efficiency of an electric machine can be improved.

  Moreover, it replaces with a lamination | stacking core and the compacting core comprised by press-molding the composition which mixed the magnetic powder and resin which were insulated was known (for example, refer patent document 2). In the dust core, since the eddy current generation region is subdivided, the path through which the eddy current flows is shortened, and the eddy current loss in the electric machine can be suppressed to be small.

JP 2003-52142 A JP 2006-339525 A

  However, a coil formed by winding a conductive wire is likely to be twisted due to the characteristics of the winding operation, and it is difficult to manufacture a coil having a complicated shape. For this reason, there are restrictions on the shape of the coil, and the characteristics of the armature may not be sufficiently improved.

  In addition, since the dust core has a low mechanical strength, there is a risk of chipping or breaking when the coil is wound around the dust core. For this reason, the dust core has been conventionally used for products that are difficult to be loaded such as inductors, but has not been used for products that are easily loaded such as armatures of electric machines.

  An object of the present invention is to provide an armature coil manufacturing method capable of manufacturing an armature coil having a high degree of freedom in shape and exhibiting good characteristics, and an armature capable of manufacturing an armature capable of realizing a highly efficient electric machine. An object of the present invention is to provide a manufacturing method and a manufacturing method of an electric machine capable of manufacturing an electric machine with high efficiency.

Such an object is achieved by the present invention described below.
The method for manufacturing an armature coil according to the present invention includes a step of forming a metal powder having conductivity using a coil molding die composed of an organic material to obtain a coil molded body,
Heating and sintering the coil molded body together with the coil molding die to obtain a coil;
It is characterized by having.

  Thereby, the coil for armatures with a high shape freedom and a favorable characteristic can be manufactured. As a result, it is possible to design a coil that places top priority on the effective use of magnetic flux, and an armature with excellent characteristics can be obtained.

In the armature coil manufacturing method of the present invention, the molding is performed on the slurry containing the metal powder and the binder,
The main component of the binder and the main component of the organic material preferably include the same chemical structure.

  Thereby, since the affinity between the slurry and the coil molding die is increased, the slurry can be molded with higher dimensional accuracy. Moreover, since the thermal expansion coefficients of the binder and the coil mold are close to each other, deformation of the coil molded body due to the difference in thermal expansion between them is suppressed, and a decrease in dimensional accuracy of the coil molded body can be suppressed.

In the method for manufacturing an armature coil of the present invention, the coil forming die has a tubular body wound in a spiral shape,
It is preferable to form the slurry by supplying the slurry to the inner space of the tube.
Thereby, the coil for armatures which can prevent a short circuit is obtained.

The method of manufacturing an armature according to the present invention includes a step of forming a metal powder having conductivity using a coil forming die made of an organic material to obtain a coil formed body,
Heating and sintering the coil molded body together with the coil molding die to obtain a coil;
Disposing the coil in the cavity of the core mold;
Supplying magnetic powder into the cavity;
A step of compacting the magnetic powder;
It is characterized by having.

  As a result, an armature including a coil that prioritizes the effective use of magnetic flux can be manufactured, so that an electric machine with high efficiency can be realized.

The method of manufacturing an armature according to the present invention includes a step of forming a metal powder having conductivity using a coil forming die made of an organic material to obtain a coil formed body,
Placing the coil compact together with the coil mold in a cavity of a core mold;
Supplying magnetic powder into the cavity;
A step of compacting the magnetic powder to obtain a core molded body including the coil molded body and the coil molding die;
Heating and sintering the core molded body including the coil molded body and the coil molding die to obtain an armature having a powder magnetic core and a coil embedded in the powder magnetic core;
It is characterized by having.

  As a result, an armature including a coil that prioritizes the effective use of magnetic flux can be manufactured, so that an electric machine with high efficiency can be realized.

  In the armature manufacturing method of the present invention, it is preferable that the magnetic powder includes a plurality of particles made of a soft magnetic material and an insulating layer covering a surface of the particles.

  Thereby, even when the particles are in contact with each other, it is possible to prevent the particles of the soft magnetic material from being conducted to each other and to prevent the insulation between the particles from being lowered. As a result, in the dust core, an eddy current generation region is subdivided, and eddy current loss can be suppressed to a small value.

  In the armature manufacturing method of the present invention, the insulating layer preferably contains a glass material.

  Thereby, an insulating layer that is excellent in chemical stability and insulation and can maintain high insulation over a long period of time can be obtained.

  In the armature manufacturing method of the present invention, it is preferable that the dust core has a columnar shape or a cylindrical shape.

  Thereby, deformation hardly occurs and molding with a large compressive force is possible at the time of molding, so that a dust core having high magnetic properties and high mechanical strength can be obtained.

The method of manufacturing an electric machine of the present invention includes a step of obtaining an armature by the method of manufacturing an armature of the present invention,
Obtaining an electric machine using the armature;
It is characterized by having.
Thereby, a highly efficient electric machine can be manufactured.

It is a disassembled perspective view which shows the direct current motor (DC motor) to which the 1st form of the electric machine manufactured by the manufacturing method of the electric machine of this invention is applied. It is a see-through | perspective perspective view which shows the armature of the direct-current motor shown in FIG. It is the top view which looked at the armature shown in FIG. 2 from the extended line of a rotating shaft, Comprising: It is a figure which shows this armature, the shaft accompanying it, a commutator, and a brush. It is sectional drawing which cut | disconnected the DC motor shown in FIG. 1 by the surface orthogonal to a rotating shaft. It is a disassembled perspective view which shows the axial gap type brushless DC motor to which the 2nd form of the electric machine manufactured by the manufacturing method of the electric machine of this invention is applied. It is sectional drawing which shows the brushless DC motor to which the 3rd form of the electric machine manufactured by the manufacturing method of the electric machine of this invention is applied. It is a figure for demonstrating the method (embodiment of the manufacturing method of the coil for armatures of this invention) which manufactures the coil of the armature shown in FIG. It is a figure for demonstrating the method (embodiment of the manufacturing method of the coil for armatures of this invention) which manufactures the coil of the armature shown in FIG. It is a figure for demonstrating the method (embodiment of the manufacturing method of the coil for armatures of this invention) which manufactures the coil of the armature shown in FIG. It is a figure for demonstrating the method (1st Embodiment of the manufacturing method of the armature of this invention) which manufactures the armature shown in FIG. It is a figure for demonstrating the method (1st Embodiment of the manufacturing method of the armature of this invention) which manufactures the armature shown in FIG. It is a figure for demonstrating the method (1st Embodiment of the manufacturing method of the armature of this invention) which manufactures the armature shown in FIG. It is a figure for demonstrating the method (2nd Embodiment of the manufacturing method of the armature of this invention) which manufactures the armature shown in FIG. It is a figure for demonstrating the method (2nd Embodiment of the manufacturing method of the armature of this invention) which manufactures the armature shown in FIG. It is a figure for demonstrating the method (2nd Embodiment of the manufacturing method of the armature of this invention) which manufactures the armature shown in FIG.

  Hereinafter, a method for manufacturing an armature coil, a method for manufacturing an armature, and a method for manufacturing an electric machine according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Electric machine>
≪First form≫
First, the 1st form of the electric machine manufactured by the manufacturing method of the electric machine of this invention is demonstrated. In the present specification, the “electric machine” refers to a motor (motor), a generator (generator), or a motor generator (motor generator) having both functions.

  FIG. 1 is an exploded perspective view showing a DC motor (DC motor) to which a first embodiment of an electric machine manufactured by the electric machine manufacturing method of the present invention is applied. 2 is a perspective view showing the armature of the DC motor shown in FIG. 1, and FIG. 3 is a plan view of the armature shown in FIG. 2 as viewed from the extension line of the rotating shaft. It is a figure which shows a child and the shaft, commutator, and brush which accompany it. FIG. 4 is a cross-sectional view of the DC motor shown in FIG. 1 cut along a plane orthogonal to the rotation axis.

  A DC motor 1A shown in FIG. 1 includes an armature 2 (rotor), a field element 3 (stator), a shaft 4, a commutator 5, a brush 62, a bracket 72, an end plate 74, Is a DC motor with a three-pole brush. Hereinafter, each part of DC motor 1A is explained in full detail. In the present specification, when the DC motor 1A is used as a motor (electric motor), a portion to which electric energy is supplied from a power source is referred to as an “armature”, and a portion that generates magnetic flux is referred to as a “field element”.

  The shaft 4 is supported by a bearing 722 provided on the bracket 72 and a bearing 742 provided on the end plate 74. The shaft 4 penetrates the armature 2 and serves as a rotating shaft of the armature 2 and also serves as an output shaft of the DC motor 1A.

  The armature 2 includes a dust core 22 (core) made of a dust compact of magnetic powder, and three coils 24 embedded in the dust core 22. Such an armature 2 is also referred to as an “induction coil”. 2 and 3, the coil 24 embedded in the dust core 22 is indicated by a broken line.

  Among these, the dust core 22 has a cylindrical shape, and the shaft 4 is inserted through the inner diameter side of the cylinder. Such a dust core 22 is composed of a powder compact of magnetic powder. Further, the particles of the magnetic powder are insulated. For this reason, eddy current loss is suppressed and a highly efficient DC motor 1A is obtained. The shape of the dust core 22 is not limited to a cylindrical shape, and may be a cylindrical shape, a rectangular tube shape, a prismatic shape, or the like.

  The coil 24 includes a winding portion 242 (see FIGS. 2 and 3) configured by winding a conducting wire in a ring shape, and a terminal portion 244 (FIG. 3) configured by both ends of the conducting wire of each winding portion 242. Reference). 2 and 3, the coil 24 is shown in a simplified manner. Further, the number of turns of the winding part 242 is not particularly limited. The coil 24 may include an insulating film that covers the surface of the conducting wire. Thereby, the insulation of the coil 24 and the powder magnetic core 22 can be improved more.

  Here, the coil 24 is embedded in the dust core 22. That is, the coil 24 does not exist in a state of being wound around, for example, a bulk core, but a winding portion 242 configured to be wound in an independent ring shape is prepared in advance. When the dust core 22 is molded with a molding die, it is molded (insert molding) with the winding portion 242 in the cavity, whereby the dust core 22 in which the winding portion 242 is embedded is formed. Is obtained.

  In such an armature 2, since the separate operation | work which winds conducting wire around a core becomes unnecessary, manufacturing efficiency is high.

  Further, since the outer shape of the dust core 22 can be determined without considering the presence of the coil 24, a simple shape such as a columnar shape or a cylindrical shape can be selected. Since the dust core 22 having such a shape is unlikely to be deformed like a so-called spring back, it can be molded with a large compressive force at the time of molding. For this reason, the magnetic properties and mechanical strength of the dust core 22 can be easily increased. Thereby, even if it uses for the application where load is easy to apply like the armature 2, the powder magnetic core 22 which can implement | achieve the armature 2 which has sufficient durability and a high dynamic characteristic is obtained.

  Moreover, since it is not necessary to wind a conducting wire around a core, it becomes easy to raise the freedom degree of the shape of the coil 24, for example, the density of the coil 24 included in the armature 2 can be raised. Thereby, it becomes easy to increase the output and torque of the DC motor 1A.

  Further, since there is no need to wind a conducting wire around the core, it is not necessary to provide a slot in the core, and the space between the conducting wires of the winding portion 242 can be filled with magnetic powder. For this reason, it becomes difficult to produce a clearance gap between the coil 24 and the dust core 22, and it becomes easy to let magnetic flux pass. As a result, magnetic flux that could not be used until now can be used for driving the DC motor 1A, and the efficiency and torque of the DC motor 1A can be increased. In addition, when a conducting wire is wound around a bulk-shaped core, a slight gap is easily generated between the core and the conducting wire. In addition, if a conductor is wound while applying high tension to eliminate the gap as much as possible, a large frictional force may be applied between the core and the conductor, causing the insulation film of the conductor to peel off or damage the core. There is. On the other hand, according to the present embodiment, this problem can be solved.

  In the present embodiment, the entire winding portion 242 of the coil 24 is embedded in the dust core 22. However, the present invention is not limited to this, and the terminal portion 244 may also be embedded. In this case, a part of the commutator 5 may be embedded in the dust core 22 so that the terminal portion 244 and the commutator 5 are electrically connected in the dust core 22.

  In addition to the above, by embedding the coil 24 in the dust core 22, the coil 24 is hardly exposed to the external environment. For this reason, it is possible to reduce the probability that the coil 24 is oxidized or deteriorated due to the influence of moisture. As a result, it is possible to extend the life of the DC motor 1A.

  Furthermore, since the shape of the dust core 22 can be freely selected, for example, the surface smoothness can be made extremely high. In addition, since the coil 24 is embedded, the influence of the shape of the coil 24 hardly appears on the surface of the dust core 22. As a result, the dust core 22 can sufficiently suppress a loss (windage loss) due to fluid resistance received from the air during rotation. For this reason, also from this viewpoint, the efficiency of the DC motor 1A can be increased.

  From the above, by embedding the coil 24 in the dust core 22, low loss, high performance, and long life can be achieved, and a highly efficient DC motor 1A can be realized.

  The shaft 4 may be inserted into the inner diameter side of the dust core 22 after the dust core 22 is formed. However, when the dust core 22 is manufactured, the shaft 4 and the coil 24 are placed in the cavity of the mold. You may make it insert by inserting and insert-molding.

  Further, the magnetic powder contained in the dust core 22 includes a soft magnetic material. Examples of soft magnetic materials include pure iron, silicon steel (Fe—Si alloy), permalloy (Fe—Ni alloy), permendur (Fe—Co alloy), and Fe—Si—Al such as Sendust. In addition to various Fe alloys such as Fe alloys, Fe—Cr—Si alloys, various Ni alloys, various Co alloys, various amorphous alloys, various metallic glasses, ferrites, and the like can be given. Among these, various Fe-based alloys are preferably used from the viewpoint of magnetic properties such as magnetic permeability and magnetic flux density, and productivity such as cost, and ferrite is preferably used from the viewpoint of cost and weather resistance.

  The average particle diameter of the magnetic powder is not particularly limited, but is preferably about 0.5 μm to 30 μm, and more preferably about 1 μm to 20 μm. By setting the average particle size of the magnetic powder within the above range, it is possible to achieve both high density of the dust core 22 and suppression of eddy current loss. If the average particle size of the magnetic powder is less than the lower limit, it is difficult to increase the density by compacting, and the mechanical strength of the dust core 22 may be reduced. On the other hand, if the average particle size of the magnetic powder exceeds the upper limit, it may be difficult to suppress eddy current loss that occurs in the magnetic powder particles.

  The average particle size of the magnetic powder is determined as the particle size when the cumulative amount from the small diameter side becomes 50% on the mass basis in the particle size distribution acquired by the laser diffraction particle size distribution measuring device.

  If the average particle size of the magnetic powder is within the above range, the maximum particle size of the magnetic powder is preferably 200 μm or less, and more preferably 150 μm or less. By setting the maximum particle size of the magnetic powder within the above range, eddy current loss is particularly suppressed, and a highly efficient armature 2 can be obtained.

  The maximum particle size of the magnetic powder is obtained as the particle size when the cumulative amount from the small diameter side becomes 99.9% on the mass basis in the particle size distribution acquired by the laser diffraction particle size distribution measuring device.

  As described above, the magnetic powder contained in the dust core 22 includes an insulating layer that covers the particle surface. Thereby, the particles of the magnetic powder are insulated. For this reason, eddy current loss is suppressed and a highly efficient DC motor 1A is obtained.

  The field element 3 includes a field magnet 32 that generates a magnetic flux, and a yoke housing 34 that supports the field magnet 32 and functions as a yoke and also functions as a housing that houses the field magnet 32 and the armature 2. Yes.

  Among these, the field magnet 32 shown in FIG. 1 is comprised with the permanent magnet. Two field magnets 32 are arranged on the inner surface of the yoke housing 34 shown in FIG. And it arrange | positions so that a mutually different magnetic pole may appear in the mutually opposing surface.

  The yoke housing 34 shown in FIG. 1 is made of a material that can form a magnetic circuit between the two field magnets 32. At the same time, the yoke housing 34 also functions as a cylindrical housing, and protects the field magnet 32 and the armature 2 housed therein from the external environment.

  The commutator 5 includes three commutator pieces 52 arranged so as to surround the side surface of the shaft 4. These commutator pieces 52 are electrically connected to the three coils 24. The three commutator pieces 52 slide while making contact with the brush 62, whereby the current flowing from the brush 62 side can be sequentially switched between the three commutator pieces 52 rotating together with the shaft 4.

  When a current flows through the coil 24 in this way, the dust core 22 is magnetized and an attractive force or a repulsive force is generated between the magnetic field core 32 and the field magnet 32. At this time, when the commutator 5 rotates together with the shaft 4, the attractive force and the repulsive force are switched, and a rotational force is generated based on the switching.

  The brush 62 is supported by the bracket 72 and is in sliding contact with the commutator 5 as described above. The DC motor 1A shown in FIG. 1 is provided with two brushes 62 and is disposed so as to face each other in a direction orthogonal to the rotation axis.

  Each brush 62 is electrically connected with a terminal 64 as shown in FIG. This terminal 64 becomes an input terminal of the DC motor 1A. Further, when the DC motor 1A is used as a generator, the terminal 64 is an output terminal.

  The bracket 72 is a member that closes one opening of the cylindrical yoke housing 34. The bracket 72 includes a bearing 722 configured by a through hole, and the shaft 4 is inserted through the bearing 722.

  The end plate 74 is a member that closes the other opening of the yoke housing 34 having a cylindrical shape. The end plate 74 includes a bearing 742 formed of a recess, and the shaft 4 is inserted into the bearing 742.

  Although the DC motor 1A has been described above, the output of the electric machine according to the present embodiment is not limited to rotational motion, and may be linear motion. That is, the electric machine according to this embodiment may be a so-called linear motor. Since the armature and the field element are used also in the linear motor, the above-described technique can be applied. Therefore, the effects described above can be achieved.

  And DC motor 1A is manufactured by assembling each part as mentioned above. In particular, by using the armature 2 as described above, a highly efficient DC motor 1A can be manufactured.

≪Second form≫
Next, a second embodiment of the electric machine manufactured by the electric machine manufacturing method of the present invention will be described.

  FIG. 5 is an exploded perspective view showing an axial gap type brushless DC motor to which a second embodiment of the electric machine manufactured by the method for manufacturing an electric machine of the present invention is applied.

  Hereinafter, the second embodiment will be described. In the following description, differences from the first embodiment described above will be mainly described, and description of similar matters will be omitted. Moreover, in the figure, the same code | symbol is attached | subjected about the matter similar to the form mentioned above.

  The axial gap type brushless DC motor 1B according to the present embodiment (hereinafter abbreviated as "AG type brushless DC motor 1B") is different in the configuration of the gap separating the rotor and the stator and is brushless. Except for the difference, it is the same as the DC motor 1A according to the first embodiment. That is, the DC motor 1A is a radial gap type brushed DC motor in which gaps spaced apart from each other are located along the radial direction of the rotating shaft, whereas the AG type brushless DC motor 1B is an extending direction of the rotating shaft. Is different in that it is an axial gap type brushless DC motor in which gaps spaced apart from each other are located along the same direction.

  An AG type brushless DC motor 1 </ b> B shown in FIG. 5 is a brushless DC motor including an armature 2 and two field elements 3. Hereinafter, each part of AG type brushless DC motor 1B is explained in full detail. In FIG. 5, the illustration of the configuration other than the armature 2 and the field element 3 (for example, a shaft) is omitted.

  The armature 2 shown in FIG. 5 is sandwiched between two field elements 3 that function as a rotor, and functions as a stator. The armature 2 includes a dust core 22 and twelve coils 24 embedded in the dust core 22. In FIG. 5, the coil 24 embedded in the dust core 22 is shown in a simplified manner with a broken line.

  On the other hand, the two field elements 3 each have a thin cylindrical plate 31 in the extending direction of the rotating shaft, and a field magnet 32 provided on the main surface on the armature 2 side of the two main surfaces of the plate 31. And.

  The dust core 22 shown in FIG. 5 has a thin cylindrical shape in the extending direction of the rotating shaft, and a shaft (not shown) is inserted into the inner diameter side of the cylinder. By using the dust core 22, eddy current loss is suppressed, and an AG type brushless DC motor 1B with high efficiency is obtained.

  Further, the twelve coils 24 are arranged so as to surround the rotating shaft. A voltage is applied to each coil 24 via, for example, an inverter. At this time, the position of the armature 2 with respect to the field element 3 is detected by a sensor or the like, and the voltage applied to each coil 24 is switched based on the position. Thereby, a rotational force is given to the armature 2.

  According to the armature 2 according to the present embodiment, the same effect as the armature 2 according to the first embodiment can be obtained. Since the armature 2 according to this embodiment can be manufactured by insert molding, a separate operation of embedding the coil 24 is not necessary, and the manufacturing efficiency is high.

  Further, since the outer shape of the dust core 22 can be determined without considering the presence of the coil 24, a simple shape such as a columnar shape or a cylindrical shape can be selected. The dust core 22 having such a shape can be molded with a large compressive force during molding, and the magnetic characteristics and mechanical strength can be easily increased. Thereby, even if it uses for the application where load is easy to apply like the armature 2, the powder magnetic core 22 which can implement | achieve the armature 2 which has sufficient durability and a high dynamic characteristic is obtained.

  In addition, it is possible to fill the space between the conductors of the winding portion 242 of the coil 24 with magnetic powder. For this reason, it becomes difficult to produce a clearance gap between the coil 24 and the dust core 22, and it becomes easy to let magnetic flux pass. As a result, magnetic flux that could not be used until now can be used for driving the AG type brushless DC motor 1B, and the AG type brushless DC motor 1B can be improved in efficiency and torque. be able to. In addition, when a conducting wire is wound around a bulk-shaped core, a slight gap is easily generated between the core and the conducting wire. In addition, if a conductor is wound while applying high tension to eliminate the gap as much as possible, a large frictional force may be applied between the core and the conductor, causing the insulation film of the conductor to peel off or damage the core. There is. On the other hand, according to the present embodiment, this problem can be solved.

  Further, since the coil 24 is not easily exposed to the external environment, the deterioration of the coil 24 with time is suppressed. As a result, it is possible to extend the life of the AG type brushless DC motor 1B.

  Furthermore, since the coil 24 is embedded, the influence of the shape of the coil 24 hardly appears on the surface of the dust core 22. For this reason, the armature 2 can be brought sufficiently close to the field element 3, and the AG type brushless DC motor 1 </ b> B can be improved in efficiency and torque.

  Also in the AG type brushless DC motor 1B provided with such an armature 2, the same effect as that of the first embodiment can be obtained.

≪Third form≫
Next, a third embodiment of the electric machine manufactured by the electric machine manufacturing method of the present invention will be described.

  FIG. 6 is a cross-sectional view showing a brushless DC motor to which a third embodiment of the electric machine manufactured by the electric machine manufacturing method of the present invention is applied.

  Hereinafter, the third embodiment will be described. In the following description, differences from the first and second embodiments described above will be mainly described, and description of similar matters will be omitted. Moreover, in the figure, the same code | symbol is attached | subjected about the matter similar to the form mentioned above.

  The brushless DC motor 1D according to the present embodiment is a radial gap type motor in which gaps that are separated from each other are positioned along the radial direction of the rotating shaft, similarly to the DC motor 1A according to the first embodiment. Further, in the brushless DC motor 1 </ b> D according to the present embodiment, the armature 2 includes the dust core 22 as in the case of the AG type brushless DC motor 1 </ b> B according to the second embodiment. Except for these differences, the brushless DC motor 1D according to the present embodiment is the same as the first and second embodiments.

  A brushless DC motor 1 </ b> D illustrated in FIG. 6 is a DC motor including an armature 2, a field element 3, and a shaft 4. In such a brushless DC motor 1D, the current flowing through the coil 24 of the armature 2 is controlled by the transistor and is driven in synchronization with the switching cycle.

  The armature 2 shown in FIG. 6 includes a dust core 22 and three coils 24 embedded in the dust core 22 and functions as a stator.

  On the other hand, the field element 3 shown in FIG. 6 includes a base portion 35 that has a cylindrical shape and the shaft 4 is inserted on the inner diameter side thereof, and a cylindrical field magnet 32 that is provided on the outer diameter side of the base portion 35. ing. The field element 3 is a so-called surface magnet type rotor.

  According to the armature 2 according to the present embodiment, the same effect as the armature 2 according to the first embodiment can be obtained. Since the armature 2 according to this embodiment can be manufactured by insert molding, a separate operation of embedding the coil 24 is not necessary, and the manufacturing efficiency is high.

  Further, since the outer shape of the dust core 22 can be determined without considering the presence of the coil 24, a simple shape such as a cylindrical shape can be selected. The dust core 22 having such a shape can be molded with a large compressive force during molding, and the magnetic characteristics and mechanical strength can be easily increased. Thereby, even if it uses for the application where load is easy to apply like the armature 2, the powder magnetic core 22 which can implement | achieve the armature 2 which has sufficient durability and a high dynamic characteristic is obtained.

  Further, since there is no need to wind a conducting wire around the core, it is not necessary to provide a slot in the core, and the space between the conducting wires of the coil 24 can be filled with magnetic powder. For this reason, magnetic flux that could not be used up to now can be used for driving the brushless DC motor 1D, and the brushless DC motor 1D can be made highly efficient and have high torque.

  Further, since the coil 24 is not easily exposed to the external environment, the deterioration of the coil 24 with time is suppressed. As a result, it is possible to extend the life of the brushless DC motor 1D.

  Furthermore, since the coil 24 is embedded, the influence of the shape of the coil 24 hardly appears on the surface of the dust core 22. For this reason, the armature 2 can be brought sufficiently close to the field element 3, and the brushless DC motor 1D can be improved in efficiency and torque.

  Also in the brushless DC motor 1D provided with such an armature 2, the same effects as those in the first and second embodiments can be obtained.

<Manufacturing method of coil for armature>
Next, an embodiment of a method for manufacturing an armature coil according to the present invention will be described.

  7-9 is a figure for demonstrating the method (embodiment of the manufacturing method of the armature coil of this invention) which manufactures the coil of the armature shown in FIG. 2, respectively.

  The manufacturing method of the coil 24 (coil for armature) shown in FIGS. 7 to 9 is as follows: [1] Metal powder 81 having conductivity is formed using a coil forming die 82 made of an organic material, and coil forming is performed. A molding step for obtaining the body 83 and [2] a heating step for heating and sintering the coil molding body 83 together with the coil molding die 82 to obtain the coil 24. Hereinafter, each process is explained in full detail.

[1] Molding step [1-1] Preparation of slurry First, a slurry containing metal powder 81 and a binder is prepared. Since this slurry has appropriate fluidity, it can be easily molded by its own weight or forced force. In the following description, a method using a slurry will be described. However, in the present invention, it is not always necessary to prepare the slurry, and the metal powder 81 may be molded as it is, or a granulated product of the metal powder 81 Alternatively, a kneaded product may be formed.

(Metal powder)
As the metal powder, conductive metal powder is used.

  Specifically, it is not particularly limited as long as it is a conductive and sinterable metal material powder, but Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Pd, Ag, In, Sn, Sb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, etc., or an alloy containing these elements can be used.

  Among these, an alloy containing at least one of Al, Cu, and Ag is particularly preferably used.

  The average particle size of the metal powder is not particularly limited, but is preferably about 1 μm to 30 μm, and more preferably about 2 μm to 20 μm. By using the metal powder having such an average particle size, the fluidity of the slurry (fluidity of the metal powder) is particularly high, and the dimensional accuracy of the coil molded body 83 can be particularly improved. When the average particle diameter of the metal powder is below the lower limit, the specific surface area of the metal powder becomes too large, so that the fluidity is lowered and the metal powder is uniformly distributed in the slurry depending on the constituent material of the metal powder. There is a risk that it cannot be dispersed. On the other hand, when the average particle diameter of the metal powder exceeds the upper limit, depending on the constituent material of the metal powder, the fluidity is lowered, and the mass of the metal powder particles becomes too large. May be unevenly distributed due to its own weight.

  The average particle size of the metal powder is a particle size when the cumulative particle size distribution obtained by laser diffraction method is 50% from the small diameter side.

  The maximum particle size of the metal powder is not particularly limited, but is preferably about 10 μm or more and 100 μm or less, and more preferably about 10 μm or more and 50 μm or less. By using the metal powder having such a maximum particle size, the fluidity of the slurry (fluidity of the metal powder) can be further enhanced, and the dimensional accuracy of the coil molded body 83 can be further enhanced. Further, since the surface roughness of the coil molded body 83 can be prevented from becoming extremely large, the insulating film provided on the surface of the finally obtained coil 24 is hardly damaged.

  The maximum particle size of the metal powder is the particle size (D99.9) when the cumulative amount is 99.9% from the small diameter side in the mass-based particle size distribution obtained by the laser diffraction method.

  Furthermore, the average particle size of the metal powder is D50, and the particle size distribution of the metal powder obtained by the laser diffraction method when the cumulative particle size distribution is 10% from the small diameter side is D10. %, When D90 is the particle diameter, (D90-D10) / D50 is preferably 0.5 or more and 5 or less, and more preferably 1.0 or more and 3.5 or less. The metal powder satisfying such conditions can achieve both high fluidity of the slurry and small shrinkage during firing. That is, the slurry is formed faithfully according to the shape of the coil mold, and the slurry is homogeneous and the variation in the shrinkage rate is small. For this reason, the coil 24 with especially high dimensional accuracy can be obtained.

  Moreover, as metal powder, what was manufactured by various powdering methods, such as an atomizing method (for example, a water atomizing method, a gas atomizing method, a high-speed rotation water stream atomizing method etc.), a reduction method, a carbonyl method, a pulverization method, is used, for example. It is done.

  Of these, those manufactured by the atomizing method are preferably used. The atomizing method is a method for producing a metal powder by causing molten metal (molten metal) to collide with a fluid (liquid or gas) jetted at high speed, thereby pulverizing and cooling the molten metal. By producing metal powder by such an atomizing method, extremely fine powder can be efficiently produced. Moreover, the particle shape of the obtained powder becomes close to a spherical shape due to the effect of surface tension. For this reason, the coil 24 with high dimensional accuracy and high surface smoothness can be obtained by using such a metal powder.

  Further, when the short diameter of the metal powder particles is S [μm] and the long diameter is L [μm], the average aspect ratio defined by L / S is about 1 to 2.5. Is preferable, and it is more preferably about 1 or more and 2 or less. The metal powder having such an aspect ratio contributes to improving the fluidity of the slurry (fluidity of the metal powder) because the shape thereof is relatively close to a sphere. As a result, the dimensional accuracy of the coil molded body 83 is increased, and the coil 24 with high dimensional accuracy can be obtained.

  The major axis is the maximum length that can be taken in the projected image of the particle, and the minor axis is the maximum length in a direction orthogonal to the maximum length. Then, the aspect ratio is obtained for 100 particles, and the average value is defined as the “average aspect ratio” described above.

(binder)
Examples of the binder include polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymers, acrylic resins such as polymethyl methacrylate and polybutyl methacrylate, styrene resins such as polystyrene, urethane resins such as polyurethane, and polychlorinated resins. Various resins such as polyesters such as vinyl, polyvinylidene chloride, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyether, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, polyvinyl pyrrolidone or copolymers thereof, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose And various organic binders such as higher fatty acid esters and higher fatty acid amides. It can be used as a mixture of at least.

  The addition amount of the binder is appropriately set according to the fluidity of the slurry, the shape and size of the coil molded body 83, the constituent material of the metal powder, etc., but 0.5 parts by mass or more with respect to 100 parts by mass of the metal powder It is preferably about 30 parts by mass or less, more preferably about 1 part by mass or more and 25 parts by mass or less, and further preferably 5 parts by mass or more and 20 parts by mass or less. By setting the addition amount of the binder within the above range, the shape retaining property of the coil molded body 83 can be sufficiently secured. Thereby, the coil 24 with high dimensional accuracy is obtained.

  Among the components described above, an aqueous binder is preferably used as the binder. By using an aqueous binder, water can be used as a solvent for the binder, so that it is possible to suppress deterioration and deterioration of the coil forming die 82 due to the slurry.

  Furthermore, among water-based binders, it is preferable to use at least one of polyvinyl alcohol and acrylic resin as a main material, and it is more preferable to use a mixture of both as a main material. Since the binder containing such a component as a main material is excellent in thermal decomposability, it is rapidly decomposed and removed (degreasing) when heated together with the coil forming die 82 in the process described later. As a result, deformation or the like of the coil molded body 83 accompanying degreasing can be suppressed. Moreover, such a binder has high adhesiveness between the metal powder particles, and contributes to enhancing the fluidity of the slurry. For this reason, the coil molded body 83 including such a binder has high shape retention and high dimensional accuracy.

  The total ratio of the polyvinyl alcohol content and the acrylic resin content in the binder is preferably 5% by mass or more and 100% by mass or less, and more preferably 10% by mass or more and 95% by mass or less. . By setting the total ratio of the content of polyvinyl alcohol and the content of acrylic resin within the above range, the thermal decomposability and adhesiveness of the binder can be made more highly compatible. This is useful in that a coil molded body 83 having a high height can be obtained.

  Moreover, when using together polyvinyl alcohol and acrylic resin, when the content rate of acrylic resin is set to 1, it is preferable that the content rate of polyvinyl alcohol is 0.2 or more and 5 or less by mass ratio, 0 More preferably, it is 5 or more and 3 or less. By setting the mixing ratio of the polyvinyl alcohol and the acrylic resin within the above range, the shape retaining property of the coil molded body 83 can be particularly improved, and finally the coil 24 with particularly high dimensional accuracy can be obtained.

  In this case, a copolymer obtained by copolymerizing polyvinyl alcohol and an acrylic resin may be used. By using such a copolymer, the effect of the combined use as described above becomes more remarkable, and the slurry becomes particularly homogeneous, so that the shape retention of the coil molded body 83 is particularly high, and the sudden degreasing process is performed. Volatilization can be suppressed.

  Examples of such a copolymer include a copolymer obtained by copolymerizing an acrylic resin with partially saponified polyvinyl alcohol.

  As the polyvinyl alcohol, those having a saponification degree of 90 mol% or more and 98 mol% or less are preferably used, and those having a saponification degree of 92 mol% or more and 94 mol% or less are more preferably used. Since such a polyvinyl alcohol has an optimized hydroxyl group content, the binder can easily adhere to the metal powder particles, and sufficient adhesiveness can be obtained even when the amount of the binder is small. As a result, a coil molded body 83 having excellent shape retention is obtained.

  In addition, the saponification degree of the polyvinyl alcohol mentioned above is measured based on the method prescribed | regulated to JISK6726.

  As the polyvinyl alcohol, those having a degree of polymerization of about 100 or more and 3000 or less are preferably used, and those having a degree of polymerization of about 200 or more and 2500 or less are more preferably used. Since such polyvinyl alcohol gives sufficient mechanical strength to the binder, a coil molded body 83 having particularly excellent shape retention can be obtained.

  In addition, the polymerization degree of the polyvinyl alcohol mentioned above is measured based on the method prescribed | regulated to JISK6726.

(solvent)
The solvent is not particularly limited as long as it can dissolve or disperse the binder and does not cause deterioration or deterioration of the coil mold 82. In addition to water, terpineol, butyl carbitol, dipropylene glycol Organic solvents such as methyl ether (DPM), acetone, methyl isobutyl ketone, ethanol, propanol, butanol, toluene and xylene are used. Moreover, you may make it use the mixed solvent containing these at least 1 sort as needed.

  Although the content rate of the binder in a slurry is suitably set according to the composition etc., it is preferable that it is about 1 mass% or more and 5 mass% or less. Moreover, although the content rate of the solvent in a slurry is suitably set according to the composition etc., it is preferable that it is about 10 mass% or more and 50 mass% or less.

  In addition to the above, various additives such as dispersants, lubricants, antifoaming agents, plasticizers, antioxidants, rust inhibitors, surfactants, and degreasing accelerators are added to the slurry as necessary. May be. In this case, the total amount of these additives is preferably set to be 10% by mass or less in the slurry.

  The viscosity of the slurry is not particularly limited, but is preferably 0.005 Pa · s to 5 Pa · s at room temperature. The slurry viscosity is measured with a Brookfield viscometer.

  Examples of the plasticizer include phthalic acid esters (eg, DOP, DEP, DBP), adipic acid esters, trimellitic acid esters, sebacic acid esters, etc., and one or more of these may be mixed. Can be used.

  Examples of the lubricant include waxes, higher fatty acids, alcohols, fatty acid metals, nonionic surfactants, silicone-based lubricants, and the like, and one or a mixture of two or more thereof is used.

  Among these, as waxes, for example, plant wax such as candelilla wax, carnauba wax, rice wax, wax, jojoba oil, animal wax such as beeswax, lanolin, spermaceti, montan wax, ozokerite, Mineral wax such as ceresin, paraffin wax, microcrystalline wax, natural wax such as petroleum wax such as petrolatum, synthetic hydrocarbons such as polyethylene wax, montan wax derivatives, paraffin wax derivatives, microcrystalline wax derivatives Modified wax, hydrogenated wax such as hydrogenated castor oil, hydrogenated castor oil derivative, fatty acid such as 12-hydroxystearic acid, acid amide such as stearamide, esthetic such as phthalimide anhydride Synthetic waxes and the like.

  Examples of higher fatty acids include stearic acid, oleic acid, linoleic acid and the like, and saturated fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and arachidic acid are particularly preferably used.

  Examples of alcohols include polyhydric alcohols, polyglycols, polyglycerols, and the like, and cetyl alcohol, stearyl alcohol, oleyl alcohol, mannitol, and the like are particularly preferably used.

  Examples of the fatty acid metal include lauric acid, stearic acid, succinic acid, stearyl lactic acid, lactic acid, phthalic acid, benzoic acid, hydroxystearic acid, ricinoleic acid, naphthenic acid, oleic acid, palmitic acid, and erucic acid. Examples include compounds of higher fatty acids and metals such as Li, Na, Mg, Ca, Sr, Ba, Zn, Cd, Al, Sn, Pb, and Cd. In particular, magnesium stearate, calcium stearate, sodium stearate Zinc stearate, calcium oleate, zinc oleate, magnesium oleate and the like are preferably used.

  Examples of nonionic surfactant-based lubricants include Electro Stripper TS-2, Electro Stripper TS-3 (both manufactured by Kao Corporation), and the like.

  Examples of the silicone-based lubricant include dimethylpolysiloxane and modified products thereof, carboxyl-modified silicone, α-methylstyrene-modified silicone, α-olefin-modified silicone, polyether-modified silicone, fluorine-modified silicone, hydrophilic specially-modified silicone, and olefin polysiloxane. Examples include ether-modified silicone, epoxy-modified silicone, amino-modified silicone, amide-modified silicone, and alcohol-modified silicone.

  Further, by using an acrylic resin as the binder and an acrylic compound as the additive, the slurry becomes particularly homogeneous and the shape retention of the coil molded body 83 can be further enhanced.

  The weight average molecular weight of the acrylic resin used as the binder is not particularly limited, but is preferably about 200,000 to 5,000,000, more preferably about 300,000 to 4,000,000.

  On the other hand, the weight average molecular weight of the acrylic compound used as an additive is not particularly limited, but is preferably about 5000 or more and less than 200,000, and more preferably about 8000 or more and 150,000 or less.

  Furthermore, the weight average molecular weight of the acrylic resin used as the binder is preferably at least twice the weight average molecular weight of the acrylic compound used as the additive, and more preferably from 3 times to 20 times. By satisfying the relationship shown in the above range by the weight average molecular weight of both, the homogeneity of the slurry, the shape transferability, and the shape retention of the coil molded body 83 can be highly paralleled, so the dimensional accuracy is particularly high, And the coil 24 excellent in mechanical characteristics can be obtained.

[1-2] Molding of slurry using mold Next, a coil mold 82 made of an organic material is prepared. As described above, the coil molding die 82 is heated together with the coil molded body 83 when the coil molded body 83 is heated in a heating process described later. Since the coil mold 82 is made of an organic material, it is thermally decomposed and removed by heating. As a result, the coil 24 having a desired shape can be manufactured without the work of mold release.

  A coil forming die 82 shown in FIG. 7 is an example of a forming die for forming the slurry into the shape of the coil 24. Specifically, the coil forming die 82 includes a cavity 821 (inner space) corresponding to the shape of the coil 24. For example, since the coil 24 shown in FIGS. 2 and 3 has a winding portion 242 and a terminal portion 244, the cavity 821 corresponds to such a shape. That is, the coil forming die 82 has a tubular body partly wound in a spiral shape. Further, the end of the cavity 821 is opened, and the slurry can be stored in the cavity 821 (inner space) by supplying the slurry from there. By using such a coil forming die 82, the coil 24 finally obtained inevitably has each part of the winding of the coil 24 separated by the wall thickness of the tube body of the coil forming die 82. It becomes. As a result, the short circuit of the coil 24 can be prevented more reliably.

  Examples of the organic material constituting the coil mold 82 include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, and ionomer. Resin, ethylene-ethyl acrylate copolymer, ethylene- (meth) acrylic acid copolymer, methylpentene polymer, polybutene resin, polyvinyl chloride resin, vinyl chloride-vinyl chloride copolymer, (meth) acrylic Resin, polyacrylonitrile resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyester resin such as polyethylene terephthalate, polyamide resin , Poly -Bonate resin, polyvinyl alcohol resin, saponified ethylene-vinyl acetate copolymer, diene resin, polyacetal resin, polyurethane resin, nitrocellulose, biodegradable plastics such as polylactic acid, etc. A material containing at least one of them is used. In addition, (meth) acryl refers to acryl or methacryl.

  Among these, any of a polystyrene resin, a polypropylene resin, a polyester resin, and a (meth) acrylic resin is preferably used. Since these are relatively excellent in thermal decomposability, it is considered that, in the heating step described later, the shape retention of the coil molded body 83 is maintained and the coil mold 82 is more quickly decomposed and removed. . For this reason, the coil 24 with high dimensional accuracy can be manufactured more efficiently.

  Moreover, it is preferable that the composition of the main component of the organic material constituting the coil mold 82 includes the same chemical structure as that of the main component of the binder contained in the slurry. In this way, since the affinity between the slurry and the coil forming die 82 is increased, the slurry can be formed with higher dimensional accuracy. In addition, since the thermal expansion coefficients of the binder and the coil molding die 82 are close to each other, deformation of the coil molded body 83 due to the difference in thermal expansion between them is suppressed, and a decrease in dimensional accuracy of the coil molded body 83 is suppressed. Can do. Examples of this chemical structure include acyl groups such as (meth) acryloyl group and propenoyl group, and carboxylic acid derivatives such as acrylic acid and propenoic acid.

  Next, as shown in FIG. 7, the slurry containing the metal powder 81 is supplied to the cavity 821 of the coil forming die 82 and stored. As a result, as shown in FIG. 8, the slurry is formed by the cavity 821.

  The slurry is then dried. Thereby, at least a part of the solvent (dispersion medium) in the slurry is removed, and the slurry is solidified or semi-solidified. Thereby, the coil molded body 83 shown in FIG. 8 is obtained. In this state, the coil molded body 83 has shape retention. In addition, when the slurry has sufficient viscosity, it is not necessary to dry the slurry completely at this point.

  The drying may be natural drying or forced drying. Moreover, it is not necessary to remove all the solvent (dispersion medium) in the slurry.

  In this embodiment, the amorphous slurry is stored in the cavity 821 of the coil forming die 82, thereby forming the slurry into a predetermined shape. However, the forming method using the coil forming die 82 is not limited to this, For example, the slurry may be formed into a tubular shape by applying the slurry to the outer surface of the coil forming die 82.

[2] Heating step [2-1] Degreasing treatment In the state where the coil molded body 83 (slurry) is formed in the cavity 821 of the coil molding die 82, the degreasing treatment is performed. Thereby, the solvent (dispersion medium) and binder in the coil molded body 83 are decomposed and removed. At the same time, the organic material constituting the coil forming die 82 is also decomposed and removed. As a result, the coil forming die 82 almost disappears, and a degreased body obtained by degreasing the coil molded body 83 is obtained.

  The degreasing process may be performed as necessary. For example, the degreasing process may be combined with a degreasing process in a baking process described later.

  The degreasing treatment is performed by a method of heating the coil molded body 83 together with the coil molding mold 82, a method of exposing the coil molding mold 82 on which the coil molded body 83 is formed, to an organic substance decomposition gas, and the like.

  Among these, the heating conditions in the degreasing treatment are appropriately set according to the composition of the binder in the coil molded body 83 and the organic material constituting the coil molding die 82, but the temperature is 100 ° C. or higher and 750 ° C. or lower and 0.1 hour. It is preferably about 20 hours or less and more preferably about 150 ° C. or more and 600 ° C. or less × 0.5 hours or more and 15 hours or less. Thereby, it is possible to perform necessary and sufficient thermal decomposition of the binder and the organic material without sintering the coil molded body 83. Examples of the heating atmosphere include a reducing atmosphere such as hydrogen, an inert atmosphere such as nitrogen and argon, and an oxidizing atmosphere such as air.

On the other hand, examples of the organic substance decomposition gas include ozone gas.
Such degreasing treatment is performed in a plurality of processes (steps) under different conditions, so that degreasing can be performed while further improving the shape retention of the coil molded body 83. For example, when the thermal decomposition temperature of the binder in the slurry is lower than the thermal decomposition temperature of the organic material constituting the coil mold 82, the binder is first decomposed and removed in the first step, and then the coil in the second step. The mold 82 may be disassembled and removed.

  Moreover, you may make it perform machining, such as cutting, grinding | polishing, and cutting | disconnection with respect to the coil molded object 83 (degreasing body) after a degreasing process as needed. Since the degreased body is relatively low in hardness and relatively rich in plasticity, it can be easily machined while preventing the shape of the degreased body from collapsing. According to such machining, the coil 24 with higher dimensional accuracy can be easily obtained finally.

  In this degreasing process, it is not necessary to remove all of the binder and the organic material constituting the coil forming die 82 in the slurry, and the degreasing process may be performed so that a part of each remains.

[2-2] Firing process Next, the coil molded body 83 (degreasing body) after the degreasing process is subjected to a firing process. By this firing treatment, diffusion occurs at the interface between the particles of the metal powder, leading to sintering. As a result, the coil 24 including the winding part 242 and the terminal part 244 reflecting the shape of the coil forming die 82 is obtained (see FIG. 9).

  The firing process is performed by a method of heating the coil molded body 83. Although the heating conditions in the firing treatment are appropriately set according to the constituent material of the metal powder, as an example, the temperature is preferably 700 ° C. or higher and 1400 ° C. or lower × 0.2 hours or longer and 7 hours or shorter, and the temperature is 800 ° C. More preferably, it is about 1330 ° C. or less × 1 hour or more and 6 hours or less. Moreover, a heating atmosphere is suitably selected from what was enumerated as an atmosphere in the degreasing process mentioned above.

  The coil 24 obtained as described above has a smaller residual stress compared to the case where the coil 24 is manufactured by winding a conducting wire as in the prior art. That is, in the method of winding the conductive material, plastic deformation is caused in the conductive wire, so that the stress remains, and the coil 24 is deformed over time by relaxing the stress over time.

  On the other hand, according to the method described above, slurry is stored in the cavity 821 of the coil forming die 82 to obtain the coil forming body 83, and then the coil forming body 83 is degreased and fired together with the coil forming die 82. . For this reason, it is difficult for stress to remain in the coil molded body 83 and the coil 24 with little deformation with time can be obtained. Since deformation is suppressed, even the coil 24 having a small bending radius and a complicated shape (a shape having a high degree of freedom) can be efficiently manufactured with high dimensional accuracy. For this reason, it is possible to design the coil 24 with the highest priority given to the effective use of magnetic flux in the armature 2, and the armature 2 and the DC motor 1A having excellent characteristics can be obtained.

  On the other hand, some metal materials have high workability and low ductility, and thus have poor workability.

  On the other hand, according to the method described above, the coil 24 with high dimensional accuracy can be efficiently manufactured even when such a difficult-to-work material is used. That is, even when such a material is used, the coil 24 that faithfully reflects the shape of the coil forming die 82 can be obtained without causing significant residual stress.

  The relative density of the coil 24 thus obtained is preferably 85% or more, and more preferably 87% or more. The coil 24 having a relative density in such a range exhibits sufficient characteristics according to the mechanical characteristics and electrical characteristics inherent to the used metal material. For this reason, the coil 24 excellent in durability and electroconductivity is obtained.

<Manufacturing method of armature>
<< First Embodiment >>
Next, a first embodiment of the armature manufacturing method of the present invention will be described.

  FIGS. 10-12 is a figure for demonstrating the method (1st Embodiment of the manufacturing method of the armature of this invention) which each manufactures the armature shown in FIG.

  10-12, [1] the step of arranging the coil 24 in the cavity 91 of the core mold 9, and [2] the step of supplying the magnetic powder 20 into the cavity 91. [3] A step of compacting the magnetic powder 20 to obtain the armature 2 having the dust core 22 and the coil 24 embedded in the dust core 22. Hereinafter, each step will be described.

  [1] First, the coil 24 is prepared (see FIG. 10). 10 to 12 show the coil 24 in a simplified manner.

  Next, the core mold 9 is prepared, and the coil 24 is disposed in the cavity 91 (see FIG. 11). When a plurality of coils 24 are arranged, the arrangement is determined in consideration of the mutual positional relationship of the coils 24 in the armature 2.

  As the core mold 9, for example, a powder metallurgy press mold or an injection mold is used. Since the coil 24 is arranged in the cavity 91 of the core mold 9, a holding means for holding the coil 24 may be used as necessary.

  [2] Next, the magnetic powder 20 is supplied into the cavity 91. As the magnetic powder 20, soft magnetic powder with an insulating layer including particles of soft magnetic powder having low conductivity or particles of a soft magnetic material and an insulating layer covering the particle surface is used. Thereby, even when the particles of the magnetic powder 20 are in contact with each other, it is possible to prevent the particles of the soft magnetic material from being conducted to each other and to prevent the insulation between the particles from being lowered. As a result, in the obtained dust core 22, the eddy current generation region is subdivided, and the eddy current loss can be reduced.

Examples of the constituent material of the insulating layer include various glass materials containing, as main components, B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , Bi ₂ O ₃ , ZnO, SnO, P ₂ O _{5, and the} like. In addition to these components, the glass material includes PbO, Li ₂ O, Na ₂ O, K ₂ O, MgO, CaO, SrO, BaO, Gd ₂ O ₃ , Y ₂ O ₃ , La ₂ O _3. , Yb ₂ O _{3 and} other subcomponents may be included.

  Further, as a constituent material of the insulating layer, more specifically, for example, sodium silicate glass, soda lime glass, borosilicate glass, lead glass, aluminosilicate glass, borate glass, phosphate glass, sulfate Various glass materials such as glass and vanadate glass can be mentioned.

  Since the glass material as described above is excellent in chemical stability and insulation as compared with an organic material, an insulating layer capable of maintaining high insulation over a long period of time can be obtained.

  Of these glass materials, those having a softening point of 650 ° C. or lower are preferably used, those having a softening point of 100 ° C. or higher and 600 ° C. or lower are more preferably used, and those having a softening point of 300 ° C. or higher and 500 ° C. or lower are more preferably used. . By selecting the glass material so that the softening point is within the above range, for example, when the magnetic powder 20 is heated after the magnetic powder 20 is formed, the particles are easily bonded to each other. As a result, a dust core 22 having high mechanical strength is obtained.

  In addition, the softening point of glass material is measured by the measuring method of the softening point prescribed | regulated to JISR3103-1.

As the glass material constituting the insulating layer, in _{particular, SnO-P 2 O 5 -MgO} , SnO-P 2 O 5, Bi 2 O 3 -B 2 O 3 -ZnO, Bi 2 O 3 -ZnO-B _{2 O 3, SiO 2 -Al 2} O 3 -B 2 O 3, SiO 2 -B 2 O 3 -Al 2 O 3, SiO 2 -B 2 O 3 -ZnO, Bi 2 O 3 -B 2 O 3, ZnO—B ₂ O ₃ —SiO ₂ or the like is preferably used.

  In addition, a non-conductive inorganic material such as a ceramic material or a silicon material may be added to the glass material that constitutes the insulating layer. In this case, the amount added is, for example, about 10% by mass or less.

  The average thickness of the insulating layer is not particularly limited, but is preferably about 0.1% to 5% of the average particle diameter of the magnetic powder 20, and more preferably about 0.3% to 3%. preferable. By setting the thickness of the insulating layer within the above range with respect to the particle size of the magnetic powder 20, irregularities on the particle surface of the soft magnetic material can be sufficiently absorbed by the insulating layer. Thereby, even if the particle | grains contact, the magnetic powder 20 can ensure sufficient insulation.

  More specifically, the average thickness of the insulating layer is preferably 5 nm or more and 3000 nm or less, and more preferably 10 nm or more and 2000 nm or less. By setting the average thickness of the insulating layer within the above range, even when the particles of the magnetic powder 20 are in contact with each other, the particles of the soft magnetic material are prevented from conducting with each other, and the insulation between the particles is reduced. Can be prevented.

  The average thickness of the insulating layer is an average value of the thickness of the insulating layer at 10 points set at substantially equal intervals by observing the cross section of the particles of the magnetic powder 20 with a microscope. In addition, when the particle diameter and usage amount of the soft magnetic material used at the time of manufacturing the magnetic powder 20 and the usage amount of the insulating layer are known, the average thickness of the insulating layer can be obtained from these information by calculation. .

  Moreover, as a manufacturing method of the soft magnetic powder with an insulating layer, a method of attaching a glass material to the particle surface of the soft magnetic powder can be mentioned. Examples of the adhesion method include wet methods such as a method of applying a liquid containing glass powder to soft magnetic powder, a method of granulating soft magnetic powder while spraying a liquid containing glass powder, and the surface of soft magnetic powder. Examples thereof include a dry method such as a method of fixing a glass material to the substrate. Of these, the method of mechanically fixing the glass material to the surface of the soft magnetic powder is preferably used. Such a method can be performed under drying, and can also be performed in an inert gas if necessary. For this reason, the possibility that moisture or the like is interposed between the soft magnetic powder and the insulating layer is reduced, and alteration and deterioration of the magnetic powder 20 can be suppressed over a long period of time. In addition, by fixing mechanically, even if foreign matter, oxide film, or the like adheres to the surface of the soft magnetic powder, the insulating layer can be formed while removing or destroying them. For this reason, in the soft magnetic powder with an insulating layer, the adhesiveness of an insulating layer becomes high and an eddy current loss can be suppressed more reliably.

  Further, according to this method, a glass material having a high softening point and difficult to handle can be formed into a film as an insulating layer. For this reason, it is useful in that a wide variety of glass materials can be used.

  As a method of mechanically fixing the glass material to the surface of the soft magnetic powder, for example, there is a method of applying a device that generates a mechanical compression action and friction action to a mixed powder of soft magnetic powder and glass powder. Can be mentioned. Examples of such devices include various mills such as a hammer mill, a disk mill, a roller mill, a ball mill, a planetary mill, and a jet mill, an ong mill (registered trademark), a high-speed elliptical mixer, a mix muller (registered trademark), and Jacobson. Various friction mixers such as a mill, Mechano-Fusion (registered trademark), and Hybridization (registered trademark) can be used. In these apparatuses, it is considered that the glass powder is pressed against the surface of the soft magnetic powder and the particle surfaces are fused. As a result, a soft magnetic powder with an insulating layer formed by fixing a glass material on the particle surface of the soft magnetic powder is obtained.

  Further, the magnetic powder 20 may be supplied into the cavity 91 in the form of a granulated powder or a kneaded product. At this time, a resin material may be added to the granulated powder or the kneaded material together with the magnetic powder 20 as necessary. Such a resin material binds the particles of the magnetic powder 20 to ensure the mechanical strength of the molded body and further enhances the insulation between the particles. For this reason, in the obtained dust core 22, the eddy current generation region is particularly subdivided, and the eddy current loss can be suppressed particularly small.

  When the resin material is not added, the mechanical strength of the molded body is ensured by bonding the insulating layers together or by adding an inorganic insulating material instead of the resin material. Also good.

  Examples of such resin materials include silicone resins, epoxy resins, phenol resins, polyamide resins, polyimide resins, silicate resins, urethane resins, acrylic resins, polyester resins, polyolefin resins, and fluorine resins. Examples thereof include resins, liquid crystal polymer resins, polyphenylene sulfide resins, waxes, higher fatty acids, alcohols, fatty acid metals, nonionic surfactants, and silicone lubricants.

  Of these, epoxy resins are preferably used. Epoxy resin is suitable as a resin material to be added together with the magnetic powder 20 because it has high insulation and good mechanical properties.

  Note that the cavity 91 may contain a material other than a resin material, for example, an inorganic insulating material such as a glass material, a ceramic material, or a silicon material, if necessary.

  [3] Next, the magnetic powder 20 is compacted to obtain a dust core 22 (see FIG. 12). In FIG. 12, the inside of the core mold 9 is seen through.

For compacting, for example, a press molding method, an injection molding method or the like is applied.
In this manner, the particles of the magnetic powder 20 are in close contact with each other, shape retention is ensured, and a molded body is obtained.

Molding pressure in this case is not particularly limited, and is preferably 1MPa or more 3000MPa or more (0.01 t / cm ² or less 30t / cm ² or higher).

  Then, the obtained molded object is heated as needed. As a result, the resin material is melted and then solidified or cured, whereby the particles of the magnetic powder 20 are fixed. As a result, the mechanical strength of the dust core 22 can be further increased.

  The heating temperature at this time is preferably 130 ° C. or higher and 180 ° C. or lower, and the heating time is preferably 5 minutes or longer and 2 hours or shorter. This heating may be performed simultaneously with molding, or may be performed both during molding and after molding.

  Also, the heating atmosphere is not particularly limited, and may be an oxidizing gas atmosphere, a reducing gas atmosphere, or the like. However, in consideration of deterioration and deterioration of the soft magnetic material and the insulating layer, nitrogen gas, argon gas, etc. An inert gas atmosphere or a reduced pressure atmosphere is preferable, and an inert gas atmosphere is more preferable.

  In the above description, the manufacturing method in the case where the armature 2 functions as a rotor has been described. However, the manufactured armature 2 may function as a stator. That is, the armature 2 shown in FIG. 6 can be manufactured by the armature manufacturing method according to the present embodiment.

<< Second Embodiment >>
Next, a second embodiment of the armature manufacturing method of the present invention will be described.

  FIGS. 13-15 is a figure for demonstrating the method (2nd Embodiment of the manufacturing method of the armature of this invention), respectively, which manufactures the armature shown in FIG.

  Hereinafter, the second embodiment will be described. In the following description, the difference between the above-described armature coil manufacturing method and the above-described first embodiment will be mainly described. The description is omitted. Moreover, in the figure, the same code | symbol is attached | subjected about the matter similar to embodiment mentioned above.

  The manufacturing method of the armature according to the present embodiment is the same as that of the first embodiment except that a step of firing the magnetic powder 20 is added, and at that time, the metal powder 81 (coil molded body 83) is also fired at the same time. It is.

  That is, in the armature manufacturing method shown in FIGS. 13 to 15, [1] a conductive metal powder 81 is formed using a coil forming die 82 made of an organic material to obtain a coil formed body 83. A step, [2] a step of placing the coil molding 83 together with the coil molding die 82 in the cavity 91 of the core molding die 9, [3] a step of supplying the magnetic powder 20 into the cavity 91, [ 4] The step of compacting the magnetic powder 20 to obtain the core compact 21, and the core compact 21 including the coil compact 83 and the coil mold 82 are heated and sintered, and the dust core 22 and the pressure Obtaining an armature 2 having a coil 24 embedded in the powder magnetic core 22. Hereinafter, each step will be described.

[1] First, a slurry containing metal powder 81 and a binder is prepared.
Next, the slurry containing the metal powder 81 is supplied to the cavity 821 of the coil forming die 82 and stored (see FIG. 7). Next, the coil molded body 83 is obtained by drying the slurry (see FIG. 8).

  [2] Next, the coil molded body 83 is placed in the cavity 91 of the core mold 9 together with the coil mold 82 (see FIG. 13).

  [3] Next, the magnetic powder 20 is supplied into the cavity 91 (see FIG. 13). As the magnetic powder 20, soft magnetic powder with an insulating layer including particles of soft magnetic powder having low conductivity or particles of a soft magnetic material and an insulating layer covering the particle surface is used.

  [4] Next, the magnetic powder 20 is compacted to obtain the core molded body 21 including the coil molded body 83 and the coil molding die 82 (see FIG. 14).

  [5] Next, the core molded body 21 is heated and sintered. Thereby, the armature 2 having the dust core 22 and the coil 24 embedded in the dust core 22 is obtained.

  Specifically, the heat treatment similar to the heating step in the embodiment of the method for manufacturing the armature coil described above is performed. Thereby, the solvent (dispersion medium) and binder in the coil molded body 83 are decomposed and removed. At the same time, the organic material constituting the coil forming die 82 is also decomposed and removed. As a result, the coil forming die 82 is almost lost, and the coil 24 formed by degreasing and sintering the coil formed body 83 is obtained.

  Further, when the core compact 21 is heated, sintering occurs between the particles of the magnetic powder 20 and between the magnetic powder 20 and the coil 24. Thereby, the particles of the magnetic powder 20 are bonded to each other, the magnetic powder 20 and the coil 24 are also bonded to each other, and the armature having the dust core 22 and the coil 24 embedded in the dust core 22. 2 is obtained.

  The sintering of the particles of the magnetic powder 20 may be performed by, for example, sintering of insulating layers provided on the surface of the magnetic powder 20 or sintering via a sinterable inorganic material added together with the magnetic powder 20. It is realized by the result.

  According to the above method, the same effects as those of the above-described embodiment of the armature coil manufacturing method and the above-described armature manufacturing method can be obtained.

  In the present embodiment, both the effects of the embodiment of the armature coil manufacturing method and the effects of the first embodiment of the armature manufacturing method can be enjoyed with fewer steps.

  The armature coil manufacturing method, the armature manufacturing method, and the electric machine manufacturing method of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these.

  For example, in the present invention, an arbitrary step may be added to the configuration according to the embodiment.

DESCRIPTION OF SYMBOLS 1A ... DC motor, 1B ... Axial gap type brushless DC motor, 1D ... Brushless DC motor, 2 ... Armature, 3 ... Field element, 4 ... Shaft, 5 ... Commutator, 9 ... Core molding die, 20 ... Magnetic powder , 21 ... core molded body, 22 ... dust core, 24 ... coil, 31 ... plate, 32 ... field magnet, 34 ... yoke housing, 35 ... base, 52 ... commutator piece, 62 ... brush, 64 ... terminal, 72 ... Bracket, 74 ... End plate, 81 ... Metal powder, 82 ... Coil molding die, 83 ... Coil molding, 91 ... Cavity, 242 ... Winding part, 244 ... Terminal part, 722 ... Bearing, 742 ... Bearing, 821 …Cavity

Claims (9)

Forming a conductive metal powder by using a coil molding die composed of an organic material to obtain a coil molded body;
Heating and sintering the coil molded body together with the coil molding die to obtain a coil;
The manufacturing method of the coil for armatures characterized by having. The molding is performed on the slurry containing the metal powder and the binder,
The armature coil manufacturing method according to claim 1, wherein the main component of the binder and the main component of the organic material include the same chemical structure. The coil forming die has a tubular body wound spirally,
The manufacturing method of the coil for armatures of Claim 2 which supplies and shape | molds the said slurry to the inner space part of the said tubular body. Forming a conductive metal powder by using a coil molding die composed of an organic material to obtain a coil molded body;
Heating and sintering the coil molded body together with the coil molding die to obtain a coil;
Disposing the coil in the cavity of the core mold;
Supplying magnetic powder into the cavity;
A step of compacting the magnetic powder;
A method for manufacturing an armature, comprising: Forming a conductive metal powder by using a coil molding die composed of an organic material to obtain a coil molded body;
Placing the coil compact together with the coil mold in a cavity of a core mold;
Supplying magnetic powder into the cavity;
A step of compacting the magnetic powder to obtain a core molded body including the coil molded body and the coil molding die;
Heating and sintering the core molded body including the coil molded body and the coil molding die to obtain an armature having a powder magnetic core and a coil embedded in the powder magnetic core;
A method for manufacturing an armature, comprising:   6. The armature manufacturing method according to claim 4, wherein the magnetic powder includes a plurality of particles made of a soft magnetic material and an insulating layer covering a surface of the particles.   The armature manufacturing method according to claim 6, wherein the insulating layer includes a glass material.   The armature manufacturing method according to claim 4, wherein the dust core has a columnar shape or a cylindrical shape. Obtaining an armature by the method of manufacturing an armature according to any one of claims 4 to 8,
Obtaining an electric machine using the armature;
The manufacturing method of the electric machine characterized by having.

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