JP2020039251A - Motor sintered magnet, manufacturing method thereof, and permanent magnet type synchronous motor - Google Patents

Abstract

To provide a manufacturing method of a motor sintered magnet capable of improving the yield of a magnet material and reducing a processing time of grinding without reducing the performance of a motor.SOLUTION: A manufacturing method of a motor sintered magnet according to the present disclosure includes a step a of preparing a sintered magnet having a convex first main surface, a second main surface opposite to the first main surface, and side surfaces, a step b of forming a reference plane on a part of the first main surface by partially grinding the top of the first main surface of the sintered magnet, and a step c of forming a surface defining the length and/or width of the sintered magnet by grinding at least a part of the side surface of the sintered magnet, and the sintered magnet having the first main surface including the reference plane as a motor sintered magnet is manufactured.SELECTED DRAWING: Figure 5

Description

  The present disclosure relates to a method for manufacturing a sintered magnet for a motor, a sintered magnet for a motor, and a permanent magnet synchronous motor including the sintered magnet for a motor.

  Patent Document 1 discloses a method of manufacturing a permanent magnet type synchronous motor (hereinafter, may be simply referred to as “motor”) that rotates a rotor by passing a current through a winding of a stator. Specifically, it is possible to arrange the sintered magnets such that the unprocessed surfaces (black scale) are left at the respective ends of the plurality of sintered magnets embedded in the iron core of the rotor and the unprocessed surfaces are close to each other. It is disclosed in Patent Document 1. The arrangement of the sintered magnets has been devised so as not to affect the performance of the motor due to variations in the magnet properties of the unprocessed surface. The shapes of the sintered magnets are various, and each is used by being embedded in an opening provided in the iron core of the rotor.

JP-A-10-271723

  The motor described in Patent Literature 1 can reduce the processing cost of the sintered magnet, so that the price can be reduced without deteriorating the performance of the permanent magnet type synchronous motor. .

  There is a need for a method for manufacturing a sintered magnet for a motor that can further reduce the manufacturing cost, a sintered magnet for a motor, and the development of a permanent magnet type synchronous motor.

  In one aspect of the method of manufacturing a sintered magnet for a motor according to the present disclosure, a step of preparing a sintered magnet having a convex first main surface, a second main surface opposite to the first main surface, and a side surface. a, a step of forming a reference plane on a part of the first main surface by partially grinding the top of the first main surface of the sintered magnet; Forming a surface defining the length and / or width of the sintered magnet by grinding at least a portion thereof, wherein the first main surface includes the reference plane as the sintered magnet for a motor. Make a magnet.

  In one embodiment, the first main surface includes an unground surface.

  In one embodiment, the unground surface has a curved shape on both sides of the reference plane.

  In one embodiment, the method further includes a step d of forming another reference plane parallel to the reference plane on the second main surface by grinding at least a part of the second main surface of the sintered magnet.

  In one embodiment, step b and step d are performed simultaneously.

  In one embodiment, step c is performed after step a.

  In one embodiment, the method further includes a step e of processing the second main surface into a concave curved surface.

  In one embodiment, the area of the reference plane on the first main surface is 50% or less of the area of the first main surface.

  In one embodiment, the unground surface of the first main surface is maintained in a black scale state formed by a sintering process.

  The sintered magnet for a motor of the present disclosure is, in one aspect, a sintered magnet for a motor having a convex first main surface, a second main surface opposite to the first main surface, and a side surface, The first main surface includes a reference plane, and the side surface has a surface that defines a length and / or a width of the sintered magnet for a motor.

  In one embodiment, the first major surface includes a raw surface.

  In one embodiment, the unprocessed surface has a curved shape on both sides of the reference plane.

  In one embodiment, the second main surface of the sintered magnet includes another reference plane parallel to the reference plane.

  In one embodiment, the second main surface has a concave curved surface.

  In one embodiment, the area of the reference plane on the first main surface is 50% or less of the area of the first main surface.

  In one aspect, a permanent magnet synchronous motor of the present disclosure includes a rotor and a stator, the rotor includes an iron core, and a plurality of permanent magnets fixed to the iron core, and each of the plurality of permanent magnets is A sintered magnet for a motor according to any one of the above.

  According to an embodiment of the present disclosure, there is provided a method for manufacturing a sintered magnet for a motor that can improve the yield of magnet material and shorten the process time of grinding without reducing the performance of the motor. For this reason, it becomes possible to reduce the manufacturing cost of a high-performance sintered magnet for a motor and a permanent magnet type synchronous motor.

It is sectional drawing which shows typically the structural example of the permanent magnet type synchronous motor which has the conventional embedded magnet structure. It is process sectional drawing for demonstrating the conventional method of manufacturing a kamaboko type magnet. It is a perspective view showing an example of a form of a sintered magnet for motors according to the present disclosure in an embodiment (left side) and a comparative example (right side). FIG. 3 is a cross-sectional view illustrating a shape example of an embodiment (left side) and a comparative example (right side) of a sintered magnet for a motor according to the present disclosure. FIG. 4 is a process cross-sectional view for describing an embodiment of a method for manufacturing a sintered magnet for a motor according to the present disclosure. It is a perspective view which shows typically the process of grinding the top part of the 1st main surface of a sintered magnet partially. It is a perspective view which shows typically the process of forming the surface which defines the width | variety of a sintered magnet by grinding the side surface of a sintered magnet. 1 is a cross-sectional view schematically illustrating a configuration example of a rotor core according to an embodiment of the present disclosure. FIG. 9 is a cross-sectional view schematically illustrating a state in which a magnet is embedded in the rotor core of FIG. 8. It is a process sectional view for explaining an embodiment of a manufacturing method of a sintered magnet (bow type) for motors according to the present disclosure. 1 is a cross-sectional view schematically illustrating a configuration example of a permanent magnet synchronous motor according to an embodiment of the present disclosure.

  Permanent magnets (hereinafter simply referred to as “magnets”) are processed into various shapes and used for various purposes. Rare earth magnets have excellent magnetic properties and are widely used. Among them, RTB based sintered magnets (R is a rare earth element and T is a transition metal element which always contains Fe), which are known as neodymium magnets, have excellent magnetic properties and other rare earth magnets (for example, samarium cobalt). Magnets) are widely used due to their relatively low material costs.

  The magnet of the RTB-based sintered magnet is manufactured by the following method.

  First, an RTB-based alloy powder having a desired composition is prepared. A powder compact having a desired shape is produced by pressing the alloy powder. A sintered body is obtained by sintering the powder compact. If necessary, the sintered body is subjected to a heat treatment such as an aging treatment. The sintered body is subjected to machining before or after the heat treatment to obtain a magnet having a desired size and shape. Thereafter, the magnet is washed to remove grinding powder and grinding fluid (cooling fluid) attached to the magnet surface by machining. Various surface treatments may be applied for the purpose of improving corrosion resistance. After the magnetization step, the sintered body functions as a permanent magnet. In this specification, for convenience, a sintered body in a state before being magnetized is also broadly referred to as a “magnet”.

  The RTB-based sintered magnet thus manufactured is widely used for a permanent magnet type synchronous motor. In such a motor, for example, torque is generated by a rotating magnetic field formed by a copper wire (winding) wound around the teeth of the stator. A plurality of RTB-based sintered magnets are attached to a core of a rotor formed of a soft magnetic material. The permanent magnet synchronous motor includes a surface magnet type and an embedded magnet type. For example, in an embedded magnet type motor, a sintered magnet is embedded and used in each of a plurality of openings (holes or recesses) formed inside an iron core of a rotor. When a gap having a low magnetic permeability is formed inside the iron core, the magnetic resistance of the rotor increases, and the characteristics of the motor deteriorate. For this reason, the shape and size of the sintered magnet are accurately matched with the shape and size of the opening provided inside the iron core of the rotor.

  The opening for magnet embedding provided inside the iron core of the rotor has, besides a simple shape surrounded by a plane, a curved surface generally called “kamaboko type” or “bow type (arc type)”. It may have a shape including. This is because it is necessary to precisely control the distribution of the magnetic flux passing through the inside of the rotor during the rotation operation of the motor in order to improve the performance of the motor, and the shape and arrangement of the sintered magnets are important. For this reason, the processing of the sintered magnet is performed precisely over a long period of time, and the ratio of the shaved material to the whole tends to increase. This leads to a reduction in the material utilization rate, that is, the yield. Magnet materials containing expensive rare earth elements can be recycled from grinding powder (sludge) after being cut off, but an increase in manufacturing cost is inevitable.

  FIG. 1 is a cross-sectional view schematically showing a configuration example of a permanent magnet type synchronous motor having a conventional embedded magnet structure.

  In the illustrated example, the motor 1000 is a permanent magnet synchronous motor including a rotor 500 and a stator 600.

  The rotor 500 has an iron core 52 having a plurality of openings (holes or recesses) 50 extending along the rotation axis, and a plurality of permanent magnets (sintered magnets) 200 respectively arranged in the plurality of openings 50. are doing. FIG. 1 illustrates one permanent magnet (hereinafter simply referred to as “magnet”) 200 in a state before being embedded in the opening 50 of the iron core 52. In practice, a magnet is embedded inside each opening 50. The rotor 500 in this example has four poles, and four magnets 200 are embedded. The magnet 200 is magnetized outside or inside in the radial direction of the rotor 500, and the north pole and the south pole are alternately arranged on the circumferential surface of the rotor 500 along the circumferential direction. The number of poles of the rotor 500 is not limited to four, and may be two or six or more.

  Stator 600 has a plurality of teeth 64 each having winding 62 therearound. For example, a three-phase alternating current flows from the inverter circuit (not shown) to the winding 62, and a magnetic flux is generated from the tip of the tooth 64 and passes through the inside of the iron core 52 of the rotor 500. The interaction of the stator flux produced by windings 62 and the rotor flux produced by magnet 200 allows rotor 500 to rotate at the desired torque and speed.

  In the example of FIG. 1, the magnet 200 has a “kamaboko” cross-sectional shape, and extends with the same cross-sectional shape in the rotation axis direction of the rotor 500. The shape of the magnet 200 is not limited to the “kamaboko type”. The shape and size of the magnet 200 match the shape and size of the opening 50 of the iron core 52. In order to manufacture such a magnet 200, for example, processing described below has been performed.

  With reference to FIG. 2, a conventional method for manufacturing the semi-cylindrical magnet 200 will be described.

  First, as shown in step S1 of FIG. 2, a magnet 200 having a cross section larger than the final cross section of the magnet is prepared. More specifically, a sintered magnet 200 is obtained by sintering a powder compact of a magnet material by a powder metallurgy technique. The sintered magnet 200 has a first convex main surface 10, a second main surface 20 opposite to the first main surface 10, and four side surfaces 30. Next, the first main surface 10 of the sintered magnet 200 is processed so that the plane indicated by the line AA in step S2 is exposed as a reference surface. This processing is called “reference plane processing”. Thus, a flat reference plane 10S is formed on the first main surface 10 as shown in step S3. Further, by polishing the side surface 30 of the sintered magnet 200, a reference surface that defines the length and width of the sintered magnet 200 is also formed.

  "Length and / or width of the sintered magnet" means the size of the sintered magnet in a direction parallel to the reference surface. Further, the “plane that defines the length and / or width of the sintered magnet” is typically perpendicular to the reference surface of the first main surface.

  Thereafter, in step S4, the entire first main surface 10 is subjected to shape processing so as to form a curved surface 10R indicated by a broken line. This shape processing is required to form the curved surface 10R with high dimensional accuracy. Hereinafter, processing the sintered magnet 200 into a curved shape may be referred to as “shape processing”. Thus, in step S5, the sintered magnet 200 having the shape and size of the opening 50 of the rotor 500 as shown in FIG. 1 is obtained.

  According to the above-described conventional processing method, in order to perform the shape processing, it is necessary to increase the size of the magnet 200 prepared in step S1 (secure a machining allowance for the shape processing). There is. Therefore, the yield (material utilization rate) decreases in both step S2 and step S4. Further, there is also a problem that the processing time is long because high-precision processing is performed by a processing machine for performing shape processing.

  The inventor of the present invention has diligently studied the solution of such a problem, and has examined the relationship between the processing shape of the sintered magnet and the motor performance. If there is a flat reference surface at the center of the first main surface even if a part of the unprocessed surface is left, a sintered magnet that can be properly embedded in the rotor without substantially deteriorating the motor performance is realized. This led to the completion of the present invention. As a result, it is not necessary to secure a machining allowance for performing the shape processing, so that the yield (material utilization rate) can be significantly improved. Further, the machining allowance at the time of machining the reference surface is reduced, and the shape machining is not required, so that the time of the process can be shortened.

  Hereinafter, an embodiment of a sintered magnet for a motor according to the present disclosure will be described.

  First, reference is made to FIGS. The left side of FIG. 3 is a perspective view showing a shape example of the embodiment of the sintered magnet for a motor according to the present disclosure, and the right side of FIG. 3 is a perspective view showing a shape example of a conventional sintered magnet for a motor. In FIG. 3, arrows indicating the length L and the width W of the sintered magnet for motor 100 are written. FIG. 4 is a cross-sectional view illustrating a shape example of the present embodiment (left side) and a comparative example (right side). In FIG. 4, an arrow indicating the thickness T of the sintered magnet for motor 100 is written.

  As shown in FIGS. 3 and 4, the sintered magnet 100 for a motor according to the present embodiment includes a first main surface 10 having a convex shape, a second main surface 20 opposite to the first main surface 10, and a side surface 30. Having. The first main surface 10 includes a reference plane 10S, and the side surface 30 has surfaces 30W and 30L that define the length and / or width of the sintered magnet 100 for a motor. Thus, the “shape processing” is not performed on the sintered magnet for motor 100.

  In the illustrated embodiment, the first major surface 10 includes an unground surface 10N. The unground surface 10N has a curved shape on both sides of the reference plane 10S. Such a curved surface shape is not a shape formed by the above-described shape processing, but a shape formed by sintering a powder compact whose shape has been adjusted by pressing. The unground surface 10N is typically a "raw surface". Therefore, the surface 10N is maintained in a black scale state formed by the sintering process. In the present disclosure, the term “grinding” refers to physically removing a magnet material from the surface of a sintered magnet using a grindstone or the like to form a “shape”, and broadly includes “polishing”. Shall be considered. Some or all of the unground surface 10N may have undergone some “surface treatment”. The surface treatment includes chemical or physical treatment for improving weather resistance, deposition of a metal layer such as plating, application of a resin, and the like. In addition, the removal of the undesired protrusions or the undesired substances attached to a part of the unground surface 10N may not be included in the “grinding” and may be performed as necessary. Further, when performing a surface treatment such as plating or resin coating, a process for improving adhesion (for example, shot blasting or barrel polishing) is not included in “grinding”, and may be performed as needed.

  In a preferred embodiment, the area of the reference plane 10S on the first main surface 10 is 50% or less of the area of the first main surface 10, and more preferably 40% or less. The width of the reference plane 10S is, for example, not less than about 1 mm and not more than about 5 mm. If the width of the reference plane 10S is smaller than this, the function as the reference plane will not be sufficiently performed, and if it is larger than this, material and grinding time will be wasted.

  3 and 4, a reference surface 30L that defines the length L of the sintered magnet 200 and a reference surface 30W that defines the width W of the sintered magnet 200 are formed. Have been.

  Next, a method for manufacturing a sintered magnet for a motor according to an embodiment of the present disclosure will be described with reference to FIG. FIG. 5 is a process cross-sectional view for describing an embodiment of a method for manufacturing a sintered magnet for a motor according to the present disclosure.

  First, in step a, a sintered magnet 100 having a first convex main surface 10, a second main surface 20 opposite to the first main surface 10, and a side surface 30 is prepared. In this example, the second main surface 20 is a substantially flat surface. According to the present disclosure, there is no need to prepare a cross section larger than the final cross section of the magnet as compared with the above-described conventional method. That is, when the size of the final magnet is the same, the size of the sintered magnet 100 to be prepared can be reduced as compared with the conventional method (magnet 200). Thereby, the yield (material utilization rate) can be improved. For example, in the case of an RTB-based sintered magnet, it is possible to improve the yield (material utilization) by 5% or more, typically 10% or more by eliminating the shape processing.

  In step b, a reference plane 10S is formed on a part of the first main surface 10 by partially grinding the top of the first main surface 10 of the sintered magnet 100. In this example, the grinding is performed until the surface indicated by the dashed line BB in FIG. 5 is exposed. According to the embodiment of the present disclosure, as compared with step S2 in the conventional method, it is not necessary to secure an allowance for the shape processing, so that the allowance for the processing in the process b is also reduced and the time of the process is shortened. can do. Thus, the thickness T of the sintered magnet 100 reaches the design value. When the top of the first main surface 10 is partially ground, the second main surface 20 may be ground at the same time. By grinding the second main surface 20, another reference plane parallel to the reference plane 10S is formed on the second main surface (step d). Thereby, the thickness T of the sintered magnet 100 and the length and / or width in the next step c can be defined with higher accuracy.

  Next, in step c, a surface that defines the length L and / or the width W of the sintered magnet 200 is formed by grinding at least a part of the side surface 30 of the sintered magnet 100. In this example, the grinding is performed until the surface indicated by the dashed line C1-C1 and the surface indicated by the dashed line C2-C2 in FIG. 5 are exposed. Although FIG. 5 shows a surface 30W that defines the width W of the sintered magnet 100, a surface that defines the length L of the sintered magnet 100 may also be formed. As described above, the method for manufacturing a sintered magnet for a motor according to the embodiment of the present disclosure produces a sintered magnet having a first main surface including a reference plane as a sintered magnet for a motor. That is, the step of processing into a curved surface (shape processing) (the step S4) is not performed.

  FIG. 6 schematically shows a configuration example of a processing machine 700 that can be used for the grinding in the step b. This processing machine 700 includes a pair of rotating grinding wheels 70. The grinding wheels 70 face each other in parallel. Each grinding wheel 70 has a flat grinding wheel layer. Such a grinding wheel 70 can be manufactured by electrodepositing diamond abrasive grains (particle diameter: 100 μm to 200 μm). In order to obtain high processing accuracy, the grinding wheel 70 needs to be appropriately replaced with a new part.

  According to such a processing machine 700, the thickness T of the sintered magnet 100 can be adjusted by grinding both surfaces in contact with the sintered magnet 100 by the grinding wheel 70. On the other hand, FIG. 7 schematically shows the state of the grinding in step c. This grinding step can be performed by a processing machine 800 having the same configuration as the processing machine 700 in FIG. The processing machine 800 can adjust the width W of the sintered magnet 100 by the pair of rotating grinding wheels 80 grinding the side surface of the sintered magnet 100. By changing the interval between the grinding wheels 70 of the processing machine 700, the width W of the sintered magnet 100 may be adjusted using the same processing machine 700.

  These grinding processes are not limited to these devices, and may be performed using a grinding device having another configuration. The grinding of the length L of the sintered magnet 100 can also be performed using a known processing machine. Grinding to form these flat processed surfaces is easier than “shape processing” for obtaining a curved surface shape. In the processing machine illustrated in FIGS. 6 and 7, both surfaces of the sintered magnet 100 can be ground at the same time, but the grinding may be performed on each side. During the grinding process, a grinding fluid is supplied to the grinding portion.

  Thus, sintered magnet 100 in which first main surface 10 includes reference plane 10S is obtained. As shown at the bottom of FIG. 5, first main surface 10 includes unground surface 10N. The unground surface 10N has a curved shape on both sides of the reference plane 10S. This curved surface is typically an unprocessed surface and is maintained in a black scale state formed by the sintering process. The reference plane 10S according to the present embodiment is different from the conventional reference plane in the middle of manufacturing in that the reference plane 10S retains the planar shape even when it is finally embedded and used in the motor.

  The magnet thus manufactured is magnetized and then used for manufacturing a permanent magnet synchronous motor. Hereinafter, embedding in the rotor will be described.

  FIG. 8 is a cross-sectional view schematically illustrating a configuration example of the iron core 52 of the rotor 500 in the present embodiment. FIG. 9 is a cross-sectional view schematically showing a state in which the magnet 100 is embedded in the iron core of FIG.

  The iron core 52 in FIG. 8 has a plurality of openings 520. Each opening 520 includes a flat portion 10F facing the reference plane 10S on the first main surface 10 of the sintered magnet 100, a flat portion 20F facing the second main surface 20 of the sintered magnet 100, and a sintered magnet 100. And a flat portion 30F facing the side surface 30W.

  As shown in FIG. 9, a gap G may be formed between the unground surface 10N of the sintered magnet 100 and the iron core 52. This gap G is designed so that even if “variation” occurs in the shape or dimension of the surface 10N for each sintered magnet 100, it is absorbed and there is no physical interference between the surface 10N and the iron core 52. You. Since the non-ground surface 10N of the sintered magnet 100 is typically an unprocessed surface, the surface roughness is high, and “variation” is likely to occur in the shape and dimensions depending on the state of sintering.

  In the example shown in FIG. 9, the position of the unground surface 10N of the sintered magnet 100 is close to another adjacent sintered magnet 100. The surface 10N may be oxidized by a sintering step or a subsequent heat treatment or the like, and the magnet properties in the surface region may be deteriorated compared to the magnet properties inside the sintered magnet 100. For this reason, conventionally, it has been considered necessary to remove the black scale portion having deteriorated magnet properties by grinding. The present inventor has found that, without being bound by such technical common sense, even if a black scale is left in an area of 50% or more of the first main surface 10 of the sintered magnet 100, a decrease in motor performance can be avoided. .

  The shape of the sintered magnet 100 in the embodiment of the present disclosure is not limited to the “kamaboko type”, but may be the “bow type”.

  An embodiment for obtaining a bow-shaped sintered magnet will be briefly described with reference to FIG. FIG. 10 is a process cross-sectional view for describing an embodiment of a method for manufacturing a sintered magnet for a motor according to the present disclosure.

  First, in step a, a sintered magnet 100 having a first convex main surface 10, a second main surface 20 opposite to the first main surface 10, and a side surface 30 is prepared. In the cross section of the sintered magnet 100, the first main surface 10 is convex, and the second main surface 20 is concave.

  In step b, a reference plane 10S is formed on a part of the first main surface 10 by partially grinding the top of the first main surface 10 of the sintered magnet 100. In this example, the grinding is performed until the surface indicated by the dashed line BB in FIG. 5 is exposed. Thus, the thickness T of the sintered magnet 100 reaches the design value. When the top of the first main surface 10 is partially ground, another reference plane parallel to the reference plane 10S is formed on the second main surface by simultaneously or separately grinding the second main surface 20. (Step d).

  In step c, at least a portion of the side surface 30 of the sintered magnet 100 is ground to form a surface that defines the length L and / or the width W of the sintered magnet 200. Grinding is performed until the surface indicated by the dashed line C1-C1 and the surface indicated by the dashed line C2-C2 in FIG. 10 are exposed. As a result, a surface (reference plane) 30W that defines the width W of the sintered magnet 100 is formed. By grinding the other side surface 30, a surface (reference plane) that defines the length L of the sintered magnet 100 can also be formed.

  Next, in step e, the second main surface 20 is subjected to shape processing, the black scale is removed from the second main surface 20, and a curved surface 20R is formed (processed into a concave curved surface).

  Thus, the first main surface 10 includes the unground surface 10N, and the entire second main surface 20 is ground to obtain a sintered magnet for a motor. The unground surface 10N has a curved shape on both sides of the reference plane 10S, and the cross section of the sintered magnet 100 is generally arcuate. The figure processing (step e) on the second main surface 20 may be omitted.

  The present invention is effective when applied to rare earth sintered magnets of various compositions. In particular, in the case of a hard magnet material which is difficult to grind, the effect is remarkable. In addition, the adverse effect of leaving the sintered surface unprocessed without grinding is relatively negligible when the original magnet performance is high. For this reason, the present invention is applied to a high performance rare earth magnet containing Dy or Tb and exhibits excellent effects.

  FIG. 11 is a cross-sectional view schematically illustrating a configuration example of the permanent magnet type synchronous motor according to the embodiment of the present disclosure. The permanent magnet synchronous motor 1100 in this example includes a rotor 500 and a stator 600, and the configuration of the stator 600 has basically the same configuration as the motor 1000 in FIG. However, the motor 1100 in the present embodiment is a surface mount type in which the sintered magnet 200 in the above embodiment is fixed to the surface of the iron core 52 of the rotor 500. The sintered magnet 200 according to the present disclosure can be used for both embedded type and surface mount type motors.

  The sintered magnet for a motor and the method for manufacturing the same, and the permanent magnet type synchronous motor according to the present disclosure can be widely used in, for example, electric vehicles and hybrid vehicles. It can also be used for generators.

DESCRIPTION OF SYMBOLS 10 ... 1st main surface, 10S ... Reference plane, 20 ... 2nd main surface, 30 ... Side surface, 50 ... Opening, 52 ... Iron core, 62 ... Winding , 64 ... teeth, 100 ... sintered magnet, 200 ... sintered magnet, 500 ... rotor, 600 ... stator, 1000 ... permanent magnet type synchronous motor

Claims (16)

A) preparing a sintered magnet having a convex first main surface, a second main surface opposite to the first main surface, and side surfaces;
Forming a reference plane on a part of the first main surface by partially grinding the top of the first main surface of the sintered magnet; b.
Forming a surface defining the length and / or width of the sintered magnet by grinding at least a portion of the side surface of the sintered magnet; c.
Including
A method for producing a sintered magnet for a motor, the method comprising: producing a sintered magnet whose first main surface includes the reference plane as a sintered magnet for a motor.   The method for manufacturing a sintered magnet for a motor according to claim 1, wherein the first main surface includes an unground surface.   The method for manufacturing a sintered magnet for a motor according to claim 2, wherein the unground surface has a curved shape on both sides of the reference plane.   4. The method according to claim 1, further comprising: forming at least a part of the second main surface of the sintered magnet so that another reference plane parallel to the reference plane is formed on the second main surface. 5. The method for producing a sintered magnet for a motor according to any one of the above.   The method for producing a sintered magnet for a motor according to claim 4, wherein the steps (b) and (d) are performed simultaneously.   The method for producing a sintered magnet for a motor according to any one of claims 1 to 5, wherein the step (c) is performed after the step (a).   The method for manufacturing a sintered magnet for a motor according to any one of claims 1 to 5, further comprising a step (e) of processing the second main surface into a concave curved surface.   The method of manufacturing a sintered magnet for a motor according to any one of claims 1 to 7, wherein an area of the reference plane on the first main surface is 50% or less of an area of the first main surface.   The method for manufacturing a sintered magnet for a motor according to any one of claims 1 to 8, wherein the unground surface of the first main surface is maintained in a black skin state formed by a sintering process. . A sintered magnet for a motor having a first convex main surface, a second main surface opposite to the first main surface, and a side surface,
The first main surface includes a reference plane,
The sintered magnet for a motor, wherein the side surface has a surface that defines a length and / or a width of the sintered magnet for a motor.   The sintered magnet for a motor according to claim 10, wherein the first main surface includes a raw surface.   The sintered magnet for a motor according to claim 11, wherein the unprocessed surface has a curved shape on both sides of the reference plane.   The sintered magnet for a motor according to any one of claims 10 to 12, wherein the second main surface of the sintered magnet includes another reference plane parallel to the reference plane.   14. The sintered magnet for a motor according to claim 10, wherein the second main surface has a concave curved surface.   The sintered magnet for a motor according to claim 10, wherein an area of the reference plane on the first main surface is 50% or less of an area of the first main surface. A permanent magnet synchronous motor including a rotor and a stator,
The rotor, an iron core, a plurality of permanent magnets fixed to the iron core,
Has,
A permanent magnet synchronous motor, wherein each of the plurality of permanent magnets is the sintered magnet for a motor according to any one of claims 10 to 15.

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