JP2021136838A - How to make magnetic wedges, rotary electric machines, and magnetic wedges - Google Patents

Abstract

To provide a magnetic wedge with excellent heat resistance and durability, while having a contribution to achievement of both of high efficiency and high torque characteristic of a rotary electric machine.SOLUTION: A compact manufactured by performing a press molding of an Fe-based magnetic powder containing an element M which is more susceptible to oxidation than Fe and a compact manufactured by performing the press molding of low permeability metal powder containing the element M are integrally press-molded again by being set in a molding, and the resulting compact is subjected to thermal processing to form an oxidation phase containing the element M between the powder particles to manufacture a magnetic wedge having a high strength and a high electric resistance by connecting both of the powder particles. By positioning a low permeability part at a width direction near center of the magnetic wedge, both of the high efficiency and the high torque characteristic of the rotary electric machine can be achieved. In addition, since the magnetic wedge has no resin, the magnetic wedge without deterioration in strength or dimension change and with heat resistance and durability even in the case of being used under a high temperature environment for a long period can be obtained.SELECTED DRAWING: Figure 10

Description

The present invention relates to a magnetic wedge used in a rotary electric machine, a rotary electric machine using the magnetic wedge, and a method for manufacturing the magnetic wedge.

In a general radial gap type rotary electric machine, a stator (hereinafter referred to as a stator) and a rotor (hereinafter referred to as a rotor) are arranged coaxially, and a plurality of teeth wound with a coil are placed on a stator around the rotor in the circumferential direction, etc. Arranged at intervals. Further, a magnetic wedge may be arranged at the rotor-side tip of the teeth so as to connect the tips of adjacent teeth. In this case, unlike the coil parts and the like, the magnetic wedge is used without winding the coil around the magnetic wedge itself.

By arranging such a magnetic wedge, the magnetic flux reaching the coil from the rotor can be magnetically shielded, and the eddy current loss of the coil can be suppressed. In addition, by arranging the magnetic wedge, the magnetic flux distribution in the gap between the stator and the rotor (particularly the magnetic flux distribution in the circumferential direction) is smoothed, and not only the rotation of the rotor is smoothed, but also the eddy current loss generated in the rotor is lost. Can also be reduced. The merit of such a magnetic wedge becomes more remarkable as the magnetic permeability of the magnetic wedge increases.

On the other hand, due to the presence of the magnetic wedge, a part of the magnetic flux that should flow from the teeth to the rotor is short-circuited between the teeth via the magnetic wedge, the magnetic flux flowing to the rotor decreases, and the torque of the rotating electric machine decreases. There is a side effect. Such side effects become more remarkable as the magnetic permeability of the magnetic wedge increases. That is, the merit of the magnetic wedge (lower loss, that is, higher efficiency) and the side effect (lower torque) are in a trade-off relationship with the magnetic permeability as a parameter. For this reason, the conventional magnetic wedge is in a state where the relative magnetic permeability is suppressed to about 5 to avoid an excessive decrease in torque, and the efficiency is improved to some extent, and the effect is limited.

In order to break the above trade-off relationship, it has been proposed to form a portion having a high reluctance (high reluctance portion) in a part of the magnetic wedge (particularly near the center in the width direction) (Patent Documents 1 and 2). .. The high reluctance portion is a portion having a low magnetic permeability (low magnetic permeability portion) because the thickness of the magnetic wedge is partially reduced or the magnetic wedge is formed of a material having a low magnetic permeability. Further, a portion having a high magnetic permeability (high magnetic permeability portion) is formed at both ends in the width direction of the magnetic wedge so as to sandwich the high magnetic resistance portion. With such a configuration, the magnetic flux short-circuited via the magnetic wedge is limited to suppress the torque decrease, and the efficiency is improved at the same time.

In the magnetic wedges described in Patent Documents 1 and 2, a high magnetic permeability portion is formed of a laminate of electromagnetic steel sheets or a green compact of ferromagnetic metal powder, and a low magnetic permeability portion is formed of a resin. Since the resin is non-magnetic, it has a low magnetic permeability (specific magnetic permeability is 1), and because it is electrically insulating, it also contributes to the suppression of eddy current loss.

JP-A-2007-221913 JP-A-2019-97258

Although Patent Document 1 mentions that magnetic powder is pressure-molded to form a high magnetic permeability portion (referred to as "core portion" in Patent Document 1), a specific description of the powder to be used and the production method is given. There is no. Further, in Patent Document 2, since it is necessary to laminate a large number of small pieces of electrical steel sheets to form a high magnetic permeability portion, the processing and laminating process are complicated, and there are problems in mass productivity and cost. Further, in any of the above patent documents, a resin is used for the low magnetic permeability portion. Therefore, when exposed to a high temperature environment for a long time, the resin is decomposed and deteriorated, gradually causing irreversible dimensional reduction and strength reduction. Therefore, it is necessary to periodically overhaul the rotating electric machine and replace the magnetic wedge, which poses a problem in terms of maintainability and maintenance cost.

Therefore, the present invention provides a magnetic wedge that is a magnetic wedge and has excellent mass productivity and durability, and a method for manufacturing the same.

The magnetic wedge of the present invention is composed of a plurality of portions having different magnetic permeability, and the first portion of the plurality of portions is composed of a plurality of Fe-based soft magnetic alloy particles containing an element M that is more easily oxidized than Fe. , It is characterized in that it is bound by an oxide phase containing the element M.

Further, in the magnetic wedge of the present invention, the second portion of the plurality of portions contains an element M having a magnetic permeability lower than that of the Fe-based soft magnetic alloy particles and more easily oxidized than Fe. It is preferably composed of a plurality of low magnetic permeability metal particles, and the low magnetic permeability metal particles are bound by an oxide phase containing the element M.

Further, in the magnetic wedge of the present invention, the low magnetic permeability metal particles are Fe-based alloy particles containing the element M, and the Fe concentration contained in the Fe-based alloy particles is the Fe-based soft magnetic alloy particles. It is preferably lower than the Fe concentration.

Further, in the magnetic wedge of the present invention, it is preferable that the boundary between the first portion and the second portion is bound by an oxide phase containing the element M.

Further, in the magnetic wedge of the present invention, the first portion of the plurality of portions is located on both ends in the width direction of the magnetic wedge, and the second portion is located on the center side in the width direction of the magnetic wedge. It is preferable to be located.

Further, in the magnetic wedge of the present invention, it is preferable that the element M is at least one of Al, Si, Cr, Zr and Hf.

Further, the rotary electric machine of the present invention uses any of the above magnetic wedges.

Further, in the method for producing a magnetic wedge of the present invention, a plurality of Fe-based soft magnetic particles containing an element M, which is more easily oxidized than Fe, and a binder are mixed, and the mixture is pressure-molded to form a first alloy. And the binder, a plurality of low magnetic permeability metal particles having a magnetic permeability lower than that of the Fe-based soft magnetic alloy particles and containing the element M are mixed, and the mixture is pressure-molded. The step of producing the second molded body, the first molded body, and the second molded body are arranged in combination in a mold and pressure-molded to obtain the first molded body. The step of producing a molded body in which the second molded body is integrated, and the heat treatment of the molded body are performed between the Fe-based soft magnetic alloy particles, between the low magnetic permeability metal particles, and the Fe group. It comprises a step of forming an oxide phase containing the element M between the soft magnetic alloy particles and the low magnetic permeability metal particles, and binding the particles with the oxide phase.

According to the present invention, it is possible to provide a magnetic wedge having excellent heat resistance, durability and mass productivity.

It is a perspective view of the magnetic wedge which is 1st Embodiment of this invention. It is an enlarged schematic view of the cross section of the magnetic wedge which is 1st Embodiment of this invention. It is a perspective view of the magnetic wedge which is the 2nd Embodiment of this invention. It is a perspective view of the magnetic wedge which is the 3rd Embodiment of this invention. It is a perspective view of the magnetic wedge which is 4th Embodiment of this invention. It is a perspective view of the magnetic wedge which is 5th Embodiment of this invention. It is a perspective view of the magnetic wedge which is the 6th Embodiment of this invention. It is a perspective view of the magnetic wedge which is 7th Embodiment of this invention. It is a perspective view of the magnetic wedge which is 8th Embodiment of this invention. It is a schematic diagram of the rotary electric machine which is the 9th Embodiment of this invention. It is a process flow about the manufacturing method of the magnetic wedge which is a tenth embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment)
FIG. 1 shows a perspective view of the magnetic wedge 100. A perspective view of the magnetic wedge 100 turned inside out is shown on the right side of the figure. The magnetic wedge 100 is composed of a plurality of portions having different magnetic permeability, and in the present embodiment, the cross section is convex as a whole. Then, the first high magnetic permeability portion 11, the low magnetic permeability portion 20, and the second high magnetic permeability portion 12 are formed in this order from one end in the width direction of the magnetic wedge 100 to the opposite end. That is, the high magnetic permeability portions 11 and 12 are located on both ends in the axial direction of the magnetic wedge 100, and the low magnetic permeability portions 20 are located on the axial center side of the magnetic wedge 100 and within the range of the convex protruding portion. It is elongated along the longitudinal direction of the magnetic wedge 100. Further, the low magnetic permeability portion 20 is arranged so as to penetrate the magnetic wedge 100 in the thickness direction. The approximate dimensions of the magnetic wedge 100 are, for example, 20 mm to 300 mm in the longitudinal direction, 2 mm to 20 mm in the width direction, and 1 to 5 mm in thickness.

FIG. 2 is a schematic view showing an enlarged boundary between the high magnetic permeability portion 11 or 12 and the low magnetic permeability portion 20. The high magnetic permeability portions 11 and 12 are composed of a plurality of Fe-based soft magnetic alloy particles, and more specifically, a compacted body of the plurality of Fe-based soft magnetic alloy particles 1 containing an element M that is more easily oxidized than Fe. Is. The compact particles have voids 2 and a surface oxide phase 3 of Fe-based soft magnetic alloy particles that bind Fe-based soft magnetic alloy particles 1 to each other. Such a surface oxide phase is an oxide phase containing the element M.

Further, the low magnetic permeability portion 20 is composed of a plurality of low magnetic permeability metal particles 4 having a magnetic permeability lower than that of the Fe-based soft magnetic alloy particles 1. Here, the low magnetic permeability metal particles 4 are characterized by containing an element M that is more easily oxidized than Fe. Further, it has a void 2 between the particles of the low magnetic permeability metal particles 4 and a surface oxide phase 5 that binds the low magnetic permeability metal particles 4 to each other. Such a surface oxide phase is an oxide phase containing the element M.

Further, a surface oxide phase 6 is formed in a place where the Fe-based soft magnetic alloy particles 1 and the low magnetic permeability metal particles 4 are adjacent to each other. The surface oxide phase 6 is formed by joining and integrating the surface oxide phase 3 of the Fe-based soft magnetic alloy particles 1 and the surface oxide phase 5 of the low magnetic permeability metal particles 4, and is composed of adjacent particles. Are in different phases. However, by containing the same element M in the Fe-based soft magnetic alloy particles 1 and the low magnetic permeability metal particles 4, the surface oxide phase 6 becomes a more homogeneous surface oxide phase 6 mainly composed of the element M. can do. As a result, the particles of the Fe-based soft magnetic alloy particles 1 and the low magnetic permeability metal particles 4 can be firmly bonded to each other.

The bending strength of the magnetic wedge 100 can be increased by firmly binding the alloy particles constituting the magnetic wedge 100 with the surface oxide phase as described above. Further, since the surface oxide phase is an insulator, the alloy particles constituting the magnetic wedge 100 can be electrically isolated from each other, and the magnetic wedge 100 as a whole can have a high electric resistance. As a result, the eddy current loss generated in the magnetic wedge 100 can be effectively suppressed.

Here, the Fe-based soft magnetic alloy particles 1 are soft magnetic alloy particles having the highest Fe content in terms of mass ratio compared to other elements, and may be soft magnetic alloy particles containing Co or Ni. However, the content of Co and Ni must not exceed the content of Fe.

Reducing the particle size of the Fe-based soft magnetic alloy particles 1 is advantageous for reducing the eddy current loss generated in the magnetic wedge 100 itself, but if the particle size is small, the production of the particles itself may become difficult. be. Therefore, in the cross-sectional observation image of the magnetic wedge 100, the average of the maximum diameters of the Fe-based soft magnetic alloy particles 1 is preferably 0.5 μm or more and 15 μm or less, and 0.5 μm or more and 8 μm or less. Is more preferable. Further, the particle number ratio having a maximum diameter of more than 40 μm is preferably less than 1.0%.

The average of the maximum diameters of each of the Fe-based soft magnetic alloy particles 1 referred to here is 30 or more particles existing in a field of view of a certain area after polishing the cross section of the magnetic wedge 100 and observing with a microscope. It is the average value of the maximum diameter of the particles read.

Further, the Fe-based soft magnetic alloy particle 1 is a particle containing an element M that is more easily oxidized than Fe. Here, "element M that is more easily oxidized than Fe" means an element having a standard Gibbs energy of oxide lower than _{Fe 2} O _3. An element satisfying this condition can be selected as the element M, but it is preferably selected from Al, Si, Cr, Zr, and Hf because it has little radical reactivity and toxicity and it is easy to manufacture the magnetic wedge 100.

By containing such an element M, a good surface oxide phase 3 that firmly binds the Fe-based soft magnetic alloy particles 1 to each other can be easily formed. Specifically, by oxidizing a plurality of Fe-based soft magnetic alloy particles 1 after molding, a surface oxide phase 3 having a higher element M content than the inside of the Fe-based soft magnetic alloy particles 1 can be easily produced. Can be formed. In particular, when Al is selected as the element M, it is particularly preferable because a good surface oxide phase 3 that is chemically stable and has high electrical resistance can be obtained.

Further, if the amount of the element M contained in the Fe-based soft magnetic alloy particles 1 is too small, the content of the element M is the Fe-based soft magnetic alloy particles 1 even if the Fe-based soft magnetic alloy particles 1 are oxidized. It becomes difficult to form a good surface oxide phase 3 higher than the inside, and if it is too much, the Fe concentration decreases, so that the saturation magnetic flux density and the curry temperature of the Fe-based soft magnetic alloy particles 1 may decrease. ..

Therefore, the amount of the element M contained in the Fe-based soft magnetic alloy particles 1 is preferably 1.0% by mass or more and 20% by mass or less. By doing so, a good surface oxide phase 3 can be easily formed, and the saturation magnetic flux density and the Curie temperature of the Fe-based soft magnetic alloy particles 1 can be maintained high.

Further, the element M may be selected not only by one type but also by two or more types. For example, two types of Al and Cr may be selected to make the Fe-based soft magnetic alloy particles 1 into Fe—Al—Cr based alloy particles. By doing so, it is possible to form a good surface oxide phase 3 in which the total content of the element M is higher than that inside the Fe-based soft magnetic alloy particles 1 even with a relatively small amount of Al. That is, the magnetic wedge 100 having high bending strength and electric resistance can be obtained. The Fe—Al—Cr alloy is an alloy in which the elements having the next highest content after Fe are Cr and Al (in no particular order), and other elements are contained in a smaller amount than Fe, Cr, and Al. You may be. The composition of the Fe—Al—Cr alloy is not particularly limited, but for example, the Al content is preferably 2.0% by mass or more, more preferably 5.0% by mass or more. From the viewpoint of obtaining a high saturation magnetic flux density, the Al content is preferably 10.0% by mass or less, more preferably 6.0% by mass or less. The Cr content is preferably 1.0% by mass or more, more preferably 2.5% by mass or more. From the viewpoint of obtaining a high saturation magnetic flux density, the Cr content is preferably 9.0% by mass or less, more preferably 4.5% by mass or less.

When two or more kinds of elements are selected for the element M, the total content thereof is preferably 1.0% by mass or more and 20% by mass or less, as in the case of selecting one kind.

Further, the Fe-based soft magnetic alloy particles 1 may be particles to which an element other than the element M is added. However, it is preferable to add these additive elements in a smaller amount than the element M. Further, the particles may be surface-treated by a chemical method or heat treatment. Further, the Fe-based soft magnetic alloy particles 1 can also be composed of a plurality of types of Fe-based soft magnetic alloy particles having different compositions.

Further, the surface oxide phase 3 may be a surface oxide phase 3 containing Fe or other elements in addition to the element M, and the concentration of the elements such as the element M and Fe is not necessarily set inside the surface oxide phase 3. It does not have to be uniform. That is, the element concentration may be different for each grain boundary.

If the thickness of the surface oxide phase 3 is small, the electrical isolation between the particles becomes small, and the electrical resistance of the magnetic wedge 100 may decrease. On the other hand, if it is thick, the magnetic permeability may become too low and the effect as a magnetic wedge may be weakened. Therefore, the thickness of the surface oxide phase 3 is preferably 0.01 to 1.0 μm, for example.

The low magnetic permeability metal particles 4 are particles having a lower magnetic permeability than the Fe-based soft magnetic alloy particles 1, and may be either a ferromagnetic material or a non-magnetic material. "Non-magnetic" here means that it is not ferromagnetic at room temperature. Specifically, it means particles exhibiting paramagnetism, diamagnetism, or antiferromagnetism at room temperature.

Further, the low magnetic permeability metal particles 4 are preferably particles containing an element M contained in the Fe-based soft magnetic alloy particles 1, that is, an element M that is more easily oxidized than Fe. For example, the element M selected from Al, Si, Cr, Zr, and Hf can be contained. By containing such an element M, a good surface oxide phase 5 similar to the surface of Fe-based soft magnetic alloy particles 1 can be formed on the surface of the low magnetic permeability metal particles 4, and the low magnetic permeability metal can be formed. The particles 4 can be firmly bonded to each other.

Further, the surface oxide phase 6 is formed by joining and integrating the surface oxide phase 3 of the Fe-based soft magnetic alloy particles 1 and the surface oxide phase of the low magnetic permeability metal particles 4, and the surface oxide phase 6 is formed by adjacent particles. The components are in different phases. However, by containing the same element M in the Fe-based soft magnetic alloy particles 1 and the low magnetic permeability metal particles 4, the surface oxide phase 6 becomes a more homogeneous surface oxide phase 6 mainly composed of the element M. can do. As a result, the Fe-based soft magnetic alloy particles 1 and the particles of the low magnetic permeability metal particles 4 can be firmly bonded to each other to form a magnetic wedge 100 having high bending strength.

Further, the low magnetic permeability metal particles 4 may be particles of the element M alone or alloy particles containing the element M. In the case of alloying particles, Fe-based alloying particles are used, and the concentration of element M is increased (that is, the content of Fe is reduced) as compared with Fe-based soft magnetic alloy particles to lower the magnetic permeability, or the magnetic permeability is further reduced. The Curie temperature of the particles may be lowered to room temperature or lower by increasing the concentration of M. In this case, the Curie temperature is preferably −20 ° C. or lower, and more preferably −100 ° C. or lower.
When the low magnetic permeability metal particles 4 are Fe-based alloy particles, for example, they are preferably metal particles containing at least one of Al and Cr, and two types of elements M, Al and Cr, are selected and Fe—Al. -It is more preferable to use Cr-based alloy particles. By doing so, good surface oxide phases 5 and 6 can be formed, and a magnetic wedge 100 having high bending strength can be obtained.

If the particle size of the low magnetic permeability metal particles 4 is large, the binding to the Fe-based soft magnetic alloy particles 1 may be hindered, or the electric resistance may be lowered to cause an eddy current loss in the low magnetic permeability portion 20. May increase. On the other hand, if the particle size is small, the production of the particles itself may become difficult. Therefore, in the cross-sectional observation image of the magnetic wedge 200, the average of the maximum diameters of the non-magnetic particles 4 is preferably 0.5 μm or more and 15 μm or less, and more preferably 0.5 μm or more and 8 μm or less. preferable. Further, the particle number ratio having a maximum diameter of more than 40 μm is preferably less than 1.0%.

Here, the higher the electrical resistance of the magnetic wedge 100 is, the more preferable it is, and the value of the volume resistivity is preferably 10 Ωm or more, and more preferably 100 Ωm or more. And it is more preferable that it is 1000 Ωm or more.
Further, the higher the bending strength of the magnetic wedge 100 is, the more preferable it is, and the value of the three-point bending strength is preferably 150 MPa or more, more preferably 200 MPa or more. And it is more preferable that it is 250 MPa or more.

As described above, since the conventional magnetic wedge contains a resin, the resin may soften and its strength may decrease in a high temperature environment. That is, when used at a high temperature such as a rotary electric machine, there is a possibility that a problem arises in bending strength. On the other hand, in the magnetic wedge 100 of the present embodiment, since the particles are bonded to each other by the surface oxide phase instead of the resin, it is possible to suppress the decrease in the binding strength between the particles at a high temperature, and the bonding strength between the particles can be suppressed under a high temperature. However, a magnetic wedge 100 having high bending strength can be provided. For example, the rate of decrease in the three-point bending strength when the temperature is raised from room temperature (25 ° C.) to 150 ° C. can be less than 5%, more preferably less than 3%. Furthermore, the rate of decrease in the three-point bending strength when the temperature is raised from room temperature (25 ° C.) to 200 ° C. can be less than 10%, more preferably less than 5%.

Further, the conventional magnetic wedge containing a resin has a problem that the resin is decomposed and deteriorated when exposed to a high temperature environment for a long time, causing an irreversible decrease in strength and size. On the other hand, in the magnetic wedge 100 of the present embodiment, since the substrate does not contain resin, such a problem does not occur. Also in this respect, the magnetic wedge 100 having excellent heat resistance and long-term reliability can be provided. For example, the mass weight loss rate after 1000 hours at 180 ° C. can be less than 0.05%, more preferably less than 0.03%. Furthermore, the mass weight loss rate after 450 hours at 220 ° C. can also be less than 0.1%, more preferably less than 0.05%.

Further, although the heat resistant temperature of the rotary electric machine varies depending on the application and specifications, there are some that are set to 155 ° C. or 180 ° C. according to the standard. In addition, in some rotary electric machines, the temperature rises to about 200 ° C. Since the magnetic wedge 100 of the present embodiment can maintain excellent bending strength even at a high temperature, a rotating electric machine having a maximum temperature of more than 180 ° C. It can also be suitably used for electric machines.

Further, it is preferable that the magnetic wedge 100 of the present embodiment has an electrically insulating coating formed on its surface. By doing so, the electric resistance of the magnetic wedge 100 can be further increased, and the particles can be suppressed from falling off from the surface of the consolidated body to obtain the highly reliable magnetic wedge 100. The coating is preferably an electrically insulating coating with a resin or oxide in order to suppress eddy current loss. For example, powder coating with an epoxy resin, coating with an inorganic substance by the Zollugel method, or sealing by impregnation with a varnish or silicon resin Pore treatment coating can be adopted. Of these, coating with an inorganic substance by the sol-gel method is particularly preferable from the viewpoint of avoiding high-temperature deterioration of the resin.

(Second Embodiment)
Next, the magnetic wedge 200 of the second embodiment of the present invention will be described. Since the magnetic wedge 200 of the present embodiment and the magnetic wedge 100 of the first embodiment differ only in the shapes of the high magnetic permeability portion and the low magnetic permeability portion, they will be described only with reference to a perspective view. Further, since the same configuration as that of the first embodiment has the same action and effect, the same symbols are added and the description thereof will be omitted.

FIG. 3 shows a perspective view of the magnetic wedge 200. A perspective view of the magnetic wedge 200 turned inside out is shown on the right side of the figure. As shown in the figure, the low magnetic permeability portion 20 does not penetrate in the thickness direction of the magnetic wedge 200, and the front side (convex surface side) surface of the magnetic wedge 200 is covered with the high magnetic permeability portion 11. By installing the magnetic wedge 200 in the rotary electric machine with this surface facing the rotor side, the magnetic flux density distribution in the gap between the rotor and the stator can be made smoother, and the magnetic flux short-circuited between the teeth via the magnetic wedge 200 can be generated. Can be effectively suppressed. As a result, it is possible to achieve both high efficiency and high torque characteristics of the rotary electric machine.

(Third Embodiment)
Next, the magnetic wedge 300 according to the third embodiment of the present invention will be described. Since the magnetic wedge 300 of the present embodiment and the magnetic wedge 100 of the first embodiment differ only in the shapes of the high magnetic permeability portion and the low magnetic permeability portion, they will be described only with reference to a perspective view. Further, since the same configuration as that of the first embodiment has the same action and effect, the same symbols are added and the description thereof will be omitted.

FIG. 4 shows a perspective view of the magnetic wedge 300. A perspective view of the magnetic wedge 300 turned inside out is shown on the right side of the figure. As shown in the figure, the cross-sectional shape of the low magnetic permeability portion 20 is substantially trapezoidal. Further, the low magnetic permeability portion 20 is formed so as to penetrate the magnetic wedge 300, and the short side of the trapezoid is located on the front side of the magnetic wedge 300 and the long side is located on the back side of the magnetic wedge 300. By installing the magnetic wedge 300 in the rotary electric machine with the front side (short side side of the trapezoidal shape) of the magnetic wedge 300 facing the rotor side, the magnetic flux density distribution in the gap between the rotor and the stator can be further smoothed, and the magnetic wedge 300 can be further smoothed. The magnetic flux short-circuited between the teeth via the 300 can be effectively suppressed. As a result, it is possible to achieve both high efficiency and high torque characteristics of the rotary electric machine.

(Fourth Embodiment)
Next, the magnetic wedge 400 according to the fourth embodiment of the present invention will be described. Since the magnetic wedge 400 of the present embodiment and the magnetic wedge 100 of the first embodiment differ only in the shapes of the high magnetic permeability portion and the low magnetic permeability portion, they will be described only with reference to a perspective view. Further, since the same configuration as that of the first embodiment has the same action and effect, the same symbols are added and the description thereof will be omitted.

FIG. 5 shows a perspective view of the magnetic wedge 400. A perspective view of the magnetic wedge 400 turned inside out is shown on the right side of the figure. As shown in the figure, the cross section of the low magnetic permeability portion 20 has a substantially triangular shape, and the base of the triangle is formed so as to be located on the back side (opposite side of the convex surface) of the magnetic wedge 400. Further, the low magnetic permeability portion 20 does not penetrate in the thickness direction of the magnetic wedge 200, and the front surface of the magnetic wedge 400 is covered with the high magnetic permeability portion 11. By installing the magnetic wedge 400 in the rotary electric machine with this surface facing the rotor side, the magnetic flux density distribution in the gap between the rotor and the stator can be made smoother, and the magnetic flux short-circuited between the teeth via the magnetic wedge 400 can be generated. Can be effectively suppressed. As a result, it is possible to achieve both high efficiency and high torque characteristics of the rotary electric machine.

(Fifth Embodiment)
Next, the magnetic wedge 500 according to the fifth embodiment of the present invention will be described. Since the magnetic wedge 500 of the present embodiment and the magnetic wedge 100 of the first embodiment differ only in the shapes of the high magnetic permeability portion and the low magnetic permeability portion, they will be described only with reference to a perspective view. Further, since the same configuration as that of the first embodiment has the same action and effect, the same symbols are added and the description thereof will be omitted.

FIG. 6 shows a perspective view of the magnetic wedge 500. A perspective view of the magnetic wedge 500 turned inside out is shown on the right side of the figure. As shown in the figure, the cross section of the low magnetic permeability portion 20 has a substantially semicircular shape, and the semicircular strings are formed so as to be located on the back side of the magnetic wedge 500. Further, the low magnetic permeability portion 20 does not penetrate in the thickness direction of the magnetic wedge 500, and the front surface of the magnetic wedge 500 is covered with the high magnetic permeability portion 11. By installing the magnetic wedge 500 in the rotary electric machine with this surface facing the rotor side, the magnetic flux density distribution in the gap between the rotor and the stator can be made smoother, and the magnetic flux short-circuited between the teeth via the magnetic wedge 500 can be generated. Can be effectively suppressed. As a result, it is possible to achieve both high efficiency and high torque characteristics of the rotary electric machine.

(Sixth Embodiment)
Next, the magnetic wedge 600 according to the sixth embodiment of the present invention will be described. Since the magnetic wedge 600 of the present embodiment and the magnetic wedge 100 of the first embodiment differ only in the shapes of the high magnetic permeability portion and the low magnetic permeability portion, they will be described only with reference to a perspective view. Further, since the same configuration as that of the first embodiment has the same action and effect, the same symbols are added and the description thereof will be omitted.

FIG. 7 shows a perspective view of the magnetic wedge 600. As shown in the figure, the low magnetic permeability portion 20 penetrates in the thickness direction of the magnetic wedge 600 and is formed obliquely in the longitudinal direction of the magnetic wedge 600. As a result, the magnetic flux density distribution in the gap between the rotor and the stator can be made smoother, and the magnetic flux short-circuited between the teeth via the magnetic wedge 600 can be effectively suppressed. Can be realized.

(7th Embodiment)
The magnetic wedge is fitted and attached to a protrusion or groove formed on the tooth of the stator as described later. Therefore, depending on this fitting form, the cross section of the magnetic wedge can take various shapes. In the above-described embodiment, the shape is described in which steps are provided at both ends of the magnetic wedge, but as shown in FIG. 8, for example, both ends of the magnetic wedge 700 may be tapered. Further, in the magnetic wedge 700 shown in FIG. 8, the cross section of the low magnetic permeability portion 20 is trapezoidal, but the present invention is not limited to this, and various shapes as described above can be applied to the shape of the low magnetic permeability portion. Can be done.

(8th Embodiment)
Next, the magnetic wedge 800 according to the eighth embodiment of the present invention will be described. FIG. 9 shows a perspective view of the magnetic wedge 800. In the magnetic wedge 800, the entire convex portion on the convex surface side is composed of the low magnetic permeability portion 20, and has a two-layer structure of the high magnetic permeability portion 11 and the low magnetic permeability portion 20 in the thickness direction. By installing the magnetic wedge 800 in the rotary electric machine with the surface on the high magnetic permeability portion 11 side facing the rotor side, even in such a configuration, it is effective in improving the efficiency of the rotary electric machine and suppressing the decrease in torque.

(9th Embodiment)
Next, the rotary electric machine 30 which is the ninth embodiment of the present invention will be described.
FIG. 10 is a schematic view of the rotary electric machine 30 and shows a cross-sectional structure perpendicular to the rotation axis of the rotary electric machine 30. The rotary electric machine 30 is a radial gap type rotary electric machine, and the stator 31 and the rotor 32 are arranged coaxially. A plurality of teeth 34 around which the coil 33 is wound are arranged on the stator 31 at equal intervals in the circumferential direction.

In the rotary electric machine 30 of the present embodiment, the above-mentioned magnetic wedge is arranged so as to connect the tips of adjacent teeth 34 to the tip of the teeth 34 on the rotor 32 side. Further, the cross-sectional shape of the magnetic wedge is convex, and the convex portion is arranged so as to be located on the rotor side. A force is applied to the magnetic wedge in the direction of being pushed out toward the rotor by the coil 33, but the flange portion of the magnetic wedge is pressed against the protrusion at the tip of the tooth to fix the magnetic wedge.

Here, the relative permeability and saturation magnetic flux density of the teeth 34 are usually designed to be higher than those of the magnetic wedge. As a result, the magnetic flux from the rotor 32 that has reached the magnetic wedge flows into the teeth 34 via the magnetic wedge, the magnetic flux that reaches the coil is suppressed, and the eddy current loss that occurs in the coil can be reduced. Further, when the rotary electric machine is driven, most of the magnetic flux in the teeth 34 generated by the coil current flows into the rotor 32 with a gap, but a part of the magnetic flux is attracted by the magnetic wedge and spreads in the circumferential direction. Become. As a result, the magnetic flux distribution in the gap between the stator 31 and the rotor 32 becomes gentle. For example, in a rotary electric machine in which a permanent magnet is arranged in the rotor 32, cogging can be suppressed, and an eddy current generated in the rotor 32 can be suppressed. The loss can be reduced. Further, for example, in an induction type rotary electric machine in which a cage-shaped conductor is arranged on the rotor 32, secondary copper loss can be reduced. By arranging the magnetic wedge according to the present invention in the rotary electric machine as described above, the loss can be reduced and the rotary electric machine 30 with high efficiency and high performance can be obtained.

If the thickness of the magnetic wedge 100 or 200 (dimension in the radial direction of the rotary electric machine) is too thin, the strength is lowered and the effect as a magnetic wedge is also weakened. Therefore, the thickness is preferably 1 mm or more. On the other hand, if it is too thick, the space of the coil 33 is compressed, which contributes to an increase in copper loss, and the volume of the magnetic wedge 100 or 200 increases, so that the loss (hysteresis loss) generated in the magnetic wedge itself also increases. Therefore, the thickness is preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 2 mm or less.
The width of the magnetic wedge 100 or 200 (dimension in the circumferential direction of the rotary electric machine) is appropriately set according to the distance between the adjacent teeth 34, but is preferably in the range of 2 mm to 20 mm.
The length of the magnetic wedge 100 or 200 (the axial dimension of the rotary electric machine) is also basically set appropriately according to the thickness (axial length) of the stator 31, but if it is too long, the manufacturing itself becomes difficult. In addition, it is easily broken when attached to a rotary electric machine, resulting in poor workability. Therefore, the length is preferably 300 mm or less, more preferably 200 mm or less, and even more preferably 100 mm or less. On the other hand, if it is too short, the work becomes complicated when it is attached to the rotary electric machine, which is not preferable. From this point of view, the length is preferably 25 mm or more, more preferably 50 mm or more.

(10th Embodiment)
Next, a method for manufacturing the magnetic wedge will be described. The following description is applicable to any of the magnetic wedges 100 to 800 of the above-described embodiment.
FIG. 11 is a process flow for manufacturing the magnetic wedges 100 to 800 of the present invention. In this production method, a step S11 in which an Fe-based soft magnetic powder and a binder are mixed to form a mixture, a step S12 in which the mixture is pressure-molded to form a first molded body, and a low magnetic permeability metal powder is used as a binder. The step S21 of mixing to form a mixture, the step S22 of press-molding the mixture to form a second molded body, and the first molded body and the second molded body are set at predetermined positions in the mold. In the step S3 of pressure molding to form a molded body integrated with the first molded body and the second molded body, and the compacted body obtained by heat-treating the integrated molded body to become a magnetic wedge 100 to 800. It has a step S4 and the like.

First, in step S11, the Fe-based soft magnetic powder and the binder are mixed to form a mixture. The Fe-based soft magnetic powder used in step S11 is a powder that becomes Fe-based soft magnetic alloy particles 1 with magnetic wedges 100 to 800. It is a soft magnetic alloy powder mainly containing Fe, and a soft magnetic powder containing Co and Ni may be used. In the following description, the particles of the Fe-based soft magnetic powder may be referred to as the Fe-based soft magnetic alloy particles 1.

As the Fe-based soft magnetic powder, it is preferable to use a powder having an average particle size (median diameter d50 in the cumulative particle size distribution) of 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 30 μm or less. By using such Fe-based soft magnetic powder, magnetic wedges 100 to 800 having Fe-based soft magnetic alloy particles 1 having a preferable average particle size can be produced.

Further, as the Fe-based soft magnetic powder, a powder containing an element M that is more easily oxidized than Fe is used, and the element M is preferably selected from, for example, Al, Si, Cr, Zr, and Hf. By doing so, in step S4, a good surface oxide phase 3 can be easily formed on the Fe-based soft magnetic alloy particles 1. Specifically, by oxidizing the molded body of the Fe-based soft magnetic powder, the surface oxide phase 3 having a higher element M content than the inside of the Fe-based soft magnetic alloy particles 1 can be easily formed. can.

The amount of the element M contained in the Fe-based soft magnetic powder is preferably 1.0% by mass or more and 20% by mass or less. By doing so, magnetic wedges 100 to 800 having high electrical resistance and bending strength and high magnetic shielding properties can be easily manufactured.

Further, the element M may be selected not only by one type but also by two or more types. For example, two types of Al and Cr may be selected, and the Fe-based soft magnetic powder may be an Fe—Al—Cr-based alloy powder. By doing so, it is possible to easily manufacture magnetic wedges 100 to 800 having high bending strength and adjusted relative magnetic permeability. The Fe—Al—Cr alloy is an alloy in which the elements having the next highest content after Fe are Cr and Al (in no particular order), and other elements are contained in a smaller amount than Fe, Cr, and Al. It may be.

When two or more kinds of elements are selected as the element M, the total content thereof is preferably 1.0% by mass or more and 20% by mass or less, as in the case of selecting one kind.

Further, as the Fe-based soft magnetic powder, a powder to which an element other than the above element M is added may be used. However, it is preferable to add these additive elements in a smaller amount than the element M. Further, a powder containing particles surface-treated by a chemical method or heat treatment may be used.

Further, as the Fe-based soft magnetic powder, a powder prepared by a gas atomizing method or a water atomizing method can be used as a granular powder having good moldability. Further, as a flat powder for the purpose of utilizing shape anisotropy, a powder produced by a pulverization method can be used.

Further, the binder is used in step S12 to temporarily bond the particles to each other to impart a certain degree of strength to the molded product. The binder also has the role of providing an appropriate spacing between the particles. As the binder, for example, an organic binder such as polyvinyl alcohol or acrylic can be used. Further, it is preferable to add the binder in an amount that is sufficiently thermally decomposed in the step S4 while sufficiently spreading the binder throughout the mixture and ensuring sufficient strength of the molded product. For example, it is preferable to add only 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the Fe-based soft magnetic powder.

Further, as the mixing method in step S11, a known mixing method and mixer can be used. A mixture of Fe-based soft magnetic powder and a binder may become agglomerated powder having a wide particle size distribution due to the adhesive action of the binder. In that case, the mixed powder may be passed through a sieve using, for example, a vibrating sieve to obtain granulated powder having a desired secondary particle size, and then used in step S12. In order to obtain granulated powder having a spherical shape and a uniform particle size, it is preferable to apply spray drying. Further, a lubricant such as stearic acid or stearate may be added to the mixture in order to reduce the friction between the powder and the mold in step S12. In that case, the addition amount is preferably 0.1 to 2.0 parts by weight with respect to 100 parts by weight of the mixed powder. The lubricant may not be added to the mixture in step S11, but may be applied to the mold in step S12.

Next, in step S12, the mixture obtained in step S11 is pressure-molded. For pressure molding, for example, a press machine and a molding die can be used. It is preferable to use a multi-axis press to form stepped shapes such as the high magnetic permeability portions 11 and 12. The pressure molding may be room temperature molding or warm molding in which the binder is heated to the extent that it does not disappear.
The molding pressure is preferably not too high from the viewpoint of leaving room for particle movement and plastic deformation in the subsequent main molding step. For example, the molding pressure is preferably 0.9 GPa or less, more preferably 0.7 GPa or less, and even more preferably 0.5 GPa or less. On the other hand, if it is too low, it becomes difficult to form a molded product, so 0.1 GPa or more is preferable, and 0.3 GPa or more is more preferable.

Next, in step S21, the low magnetic permeability metal powder and the binder are mixed to form a mixture. The low magnetic permeability metal powder used in step S21 is a powder that becomes low magnetic permeability metal particles 4 in the magnetic wedges 100 to 800. In the following description, the particles of the low magnetic permeability metal powder may be referred to as the low magnetic permeability metal particles 4.

As the low magnetic permeability metal powder, it is preferable to use a powder having an average particle size (median diameter d50 in the cumulative particle size distribution) of 1 μm or more and 80 μm or less, and more preferably 3 μm or more and 20 μm or less. By using such a low magnetic permeability metal powder, it is possible to manufacture magnetic wedges 100 to 800 having low magnetic permeability metal particles 4 having a preferable average particle size.

Further, as the low magnetic permeability metal powder, an element M contained in the Fe-based soft magnetic powder, that is, a powder containing an element M that is more easily oxidized than Fe is used, and the element M is, for example, Al, Si, Cr, Zr. , Hf is preferable. By doing so, magnetic wedges 100 to 800 having high bending strength and electrical resistance can be easily manufactured.

Further, the low magnetic permeability metal particles 4 may be particles of the element M alone or alloy particles containing the element M. In the case of alloy particles, Fe-based alloy particles are used, and the concentration of element M is increased (that is, the content of Fe is reduced) to lower the magnetic permeability, or the concentration of element M is further increased to increase the concentration of the particles. The Curie temperature may be set to room temperature or lower.
When the low magnetic permeability metal particles 4 are Fe-based alloy particles, for example, they are preferably metal particles containing at least one of Al and Cr, and two types of elements M, Al and Cr, are selected and Fe—Al. -It is more preferable to use Cr-based alloy particles. By doing so, good surface oxide phases 5 and 6 can be formed, and magnetic wedges 100 to 800 having high bending strength and electrical resistance can be obtained.

As the binder provided in the step S21, the same binder as in the above-mentioned step 11 can be used. The same applies to the amount of binder added. Further, as the mixing method in the step S21, the same mixing method as in the above-mentioned step S11 can be used. The same applies to the amount of lubricant added.

Next, in step S22, the mixture obtained in step S21 is pressure-molded. For the pressure molding, the same pressure molding as in the above-mentioned step S12 can be used. The molding pressure is preferably not too high from the viewpoint of leaving room for particle movement and plastic deformation in the subsequent main molding step. For example, the molding pressure is preferably 0.9 GPa or less, more preferably 0.7 GPa or less, and even more preferably 0.5 GPa or less. On the other hand, if it is too low, it becomes difficult to form a molded product, so 0.1 GPa or more is preferable, and 0.3 GPa or more is more preferable.

Next, for the low magnetic permeability metal particles, the molded bodies produced in steps 12 and 22 are set at predetermined positions in the mold, and then pressure molding is performed again to integrate these molded bodies. When the magnetic wedges 100 to 800 are manufactured, pressure molding is performed after setting the molded body of the high magnetic permeability portion at both ends and the molded body of the low magnetic permeability portion between them. Due to the pressure during pressure molding, the movement of particles and plastic deformation occur, the overall densification progresses, and the molded body of the high magnetic permeability portion and the molded body of the low magnetic permeability portion are brought into close contact with each other and integrated. However, the term "adhesion" as used herein means that the Fe-based soft magnetic alloy particles 1 and the low magnetic permeability metal particles 4 are adhered to each other via a binder at the boundary between the high magnetic permeability portion and the low magnetic permeability portion. Point to that.

For the pressure molding in step 3, for example, a press machine and a molding die can be used. The pressure molding may be room temperature molding or warm molding in which the binder is heated to the extent that it does not disappear. A lubricant may be applied to the inner wall of the mold. The molding pressure is preferably higher than the molding pressure in steps S12 and S22 in order to promote the above-mentioned integration. For example, the molding pressure is preferably 0.7 GPa or more, and more preferably 0.9 GPa or more. On the other hand, if it is too high, a large press machine is required and the die is significantly worn. Therefore, 2.5 GPa or less is preferable, and 2.0 GPa or less is more preferable.

Next, in step S4, the molded body obtained in step S3 is heat-treated to be a compacted body having a magnetic wedge of 100 to 800. In step S4, the molded body is heat-treated to thermally decompose the binder existing between the Fe soft magnetic particles 1 and the low magnetic permeability metal particles 4 of the molded body to form voids between the particles. By further continuing the heat treatment, the voids 2 and the surface oxide phase 3 that binds the Fe-based soft magnetic alloy particles 1 to each other and the surface oxidation that binds the low magnetic permeability metal particles 4 to each other are formed between the particles. The physical phase 5 and the surface oxide phase 6 for binding the Fe-based soft magnetic alloy particles 1 and the low magnetic permeability metal particles 4 are formed.

The heat treatment can be performed in an atmosphere in which oxygen is present, such as in the atmosphere or in a mixed gas of oxygen and an inert gas. It can also be performed in an atmosphere in which water vapor is present, such as in a mixed gas of water vapor and an inert gas.

Further, in the heat treatment, the surface oxide phase 3 that binds the Fe-based soft magnetic alloy particles 1 to each other and the surface oxide that binds the low magnetic permeability metal particles 4 to each other are bonded between the particles of the Fe-based soft magnetic alloy particles 1. The phase 5 and the surface oxide phase 6 that binds the Fe-based soft magnetic alloy particles 1 and the low magnetic permeability metal particles 4 are heated to a temperature at which they can be formed. However, if the heat treatment temperature is low, the thermal decomposition of the binder may not be completed and may remain, and the strain applied to the molded body during molding may remain unrelieved. On the other hand, if the heat treatment temperature is high, the Fe-based soft magnetic alloy particles 1 may be sintered, the electric resistance may be lowered, and the magnetic wedges 100 to 800 having a large eddy current loss may be formed. Therefore, the heat treatment temperature is preferably in the range of 600 ° C. to 900 ° C., more preferably in the range of 700 to 800 ° C.

Although not shown in FIG. 11, after the molding steps of steps S12, S22, and S3, a processing step of performing grinding and / or cutting on the molded body may be inserted. As a result, each molded product can be formed into a desired shape, and magnetic wedges 100 to 800 of various embodiments can be easily obtained. Further, it is also possible to insert a processing step after the heat treatment step of step S4. However, in this case, there is a risk of damaging the surface oxidation phase formed by the heat treatment and lowering the electrical resistance. From this point of view, a manufacturing method in which processing is performed at the stage of the molded product (before heat treatment) is more preferable.

As described above, this production method is based on press molding of a powder raw material, and a desired magnetic wedge shape can be obtained relatively easily, so that it is also excellent in mass productivity.

Although the present invention has been described above using the above-described embodiment, the technical scope of the present invention is not limited to the above-described embodiment. The contents can be changed within the technical scope described in the claims.

1: Fe-based soft magnetic alloy particles 2: voids 3: surface oxide phase 4: low magnetic permeability metal particles 5: surface oxide phase 6: surface oxide phase 30: rotary electric machine 31: stator 32: rotor 33: coil 34 : Teeth 100, 200, 300, 400, 500, 600, 700, 800: Magnetic wedge

Claims (8)

A magnetic wedge for rotary electric machines
Consists of multiple parts with different magnetic permeability
Of the plurality of portions, the first portion contains a plurality of Fe-based soft magnetic alloy particles containing an element M that is more easily oxidized than Fe.
Being bound by an oxide phase containing the element M,
A magnetic wedge featuring. Of the plurality of portions, the second portion has a lower magnetic permeability than the Fe-based soft magnetic alloy particles.
It is composed of a plurality of low magnetic permeability metal particles containing an element M that is more easily oxidized than Fe.
The magnetic wedge according to claim 1, wherein the low magnetic permeability metal particles are bound by an oxide phase containing the element M. The low magnetic permeability metal particles are Fe-based alloy particles containing the element M, and the Fe concentration contained in the Fe-based alloy particles is lower than the Fe concentration of the Fe-based soft magnetic alloy particles. The magnetic wedge according to claim 2. The boundary between the first portion and the second portion is bound by an oxide phase containing the element M.
The magnetic wedge according to any one of claims 2 and 3, wherein the magnetic wedge is characterized. Of the plurality of parts
The first portion is located on both ends in the width direction of the magnetic wedge.
The magnetic wedge according to any one of claims 2 to 4, wherein the second portion is located on the central side in the width direction of the magnetic wedge. The magnetic wedge according to any one of claims 1 to 5, wherein the element M is at least one of Al, Si, Cr, Zr, and Hf. A rotary electric machine characterized in that the magnetic wedge according to any one of claims 1 to 6 is used. A step of making a mixture of a plurality of Fe-based soft magnetic alloy particles containing an element M that is more easily oxidized than Fe and a binder, and pressure-molding the mixture to prepare a first molded body.
A second molded body is formed by mixing a plurality of low magnetic permeability metal particles having a magnetic permeability lower than that of the Fe-based soft magnetic alloy particles and containing the element M and a binder, and press-molding the mixture. And the process of making
The first molded body and the second molded body are combined and arranged in a mold to perform pressure molding, and the first molded body and the second molded body are integrated. The process of making a body and
The molded body is heat-treated, and between the Fe-based soft magnetic alloy particles, between the low magnetic permeability metal particles, and between the Fe-based soft magnetic alloy particles and the low magnetic permeability metal particles.
A step of generating an oxide phase containing the element M and binding each particle with the oxide phase.
A method for manufacturing a magnetic wedge, which comprises.

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