JP4850439B2 - Permanent magnet member for embedded magnet type rotating electrical machine and rotating electrical machine - Google Patents

Description

  The present invention relates to a permanent magnet member and a rotating electrical machine used in a rotating electrical machine using an embedded permanent magnet.

  Conventionally, for example, a permanent magnet electric machine is used as a drive source for a railway vehicle or an electric vehicle. As an example of a permanent magnet electric machine, for example, a plurality of coils are attached to a stator (stator) side fixed so as not to rotate, and a plurality of permanent magnets are connected to a drive shaft to give torque thereto. There is a permanent magnet synchronous electric machine with a magnet attached.

  In this case, the coils and the permanent magnets are arranged to face each other. Thereby, when a three-phase alternating current etc. are supplied to a coil, the alternating magnetic field which arises in this and the static magnetic field of a permanent magnet interact, and a rotor rotates synchronizing with an alternating magnetic field. At that time, a torque ripple, which is a cogging torque, is generated in the rotor due to the discontinuity of the coils of the stator. Further, in the embedded permanent magnet type rotating electrical machine, the gap magnetic flux density between the stator and the rotor becomes trapezoidal, and thus a large torque ripple is generated.

  Conventionally, in order to reduce torque ripple, the coils and teeth on the stator side are skewed obliquely. However, skewing the stator side greatly increases costs. Furthermore, in a large electric machine for driving a railway vehicle, the output torque also increases, and the cogging torque increases accordingly. In addition, in the railway vehicle driving electric machine, when the electric machine attached to the carriage at the time of maintenance is carried into the warehouse, the carriage may be carried manually. At this time, since the cogging torque is large, the work may be hindered. In order to solve these problems, the actual situation is that a method for greatly reducing the cogging torque at low cost is desired.

  Further, in a permanent magnet embedded type rotating machine, since a permanent magnet member is normally embedded in a rotor, an integral rectangular parallelepiped magnet is inserted, and a stator (armature: coil) is used to reduce cogging torque. ) The side was skewed. However, there was difficulty in construction due to the increased cost, and the cogging torque could not be reduced sufficiently. In addition, Patent Documents 1 and 2 disclose techniques for reducing the cogging torque of a permanent magnet type rotating electrical machine.

JP 2000-350393 A JP 2003-18775 A

  An object of the present invention is to provide a permanent magnet member capable of reducing cogging torque without increasing cost in an embedded magnet type rotating electrical machine.

According to one aspect of the present invention, a permanent magnet member for an embedded magnet type rotating electrical machine includes a magnet portion, and the magnet portion is perpendicular to a rotating shaft of the rotating electrical machine when the magnet portion is incorporated in the rotating electrical machine. A shape of a cross section of the magnet portion in a flat plane and / or a shape in which a positional relationship of the cross section with respect to the rotation axis is continuously changed, and the magnet portion is a shape obtained by cutting off a corner from a substantially rectangular parallelepiped. And further includes an auxiliary portion having a magnetic characteristic different from that of the magnet portion and having the same shape as the cut corner portion , wherein the auxiliary portion is magnetized from the magnet portion. A permanent magnet member made of magnets having different directions is provided. According to another aspect of the present invention, a magnet-embedded rotating electrical machine including the permanent magnet member is provided.

  In a conventional embedded permanent magnet type rotating electrical machine, the permanent magnet member has the same cross-sectional shape in the direction of the rotation axis of the rotor. Therefore, the change of the gap magnetic flux density between the permanent magnet and the iron core portion becomes large, and the cogging torque is increased.

On the other hand, according to the present invention, the rotation axis direction of the shape of the magnet cross-sectional or the like was continuously changed, by further using a different auxiliary unit having magnetic properties, be relaxed steep part of the gap magnetic flux density it can. Furthermore, by combining an auxiliary part made of a magnetization direction different magnets, it is possible to greatly reduce the cogging torque without significantly changing the output.

  As described in detail below, according to the present invention, cogging torque can be reduced in an embedded magnet type rotating electrical machine. In addition, according to the present invention, it is possible to perform construction in a short period of time at a lower cost than in the case of skewing the stator side, which has been causing an increase in cost, at a lower cost. Moreover, the magnetic flux can be concentrated by using an auxiliary portion made of magnets having different magnetization directions, and the maximum magnetic flux density can be improved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the embodiments described below do not limit the present invention.

  As described above, according to one aspect of the present invention, there is provided a permanent magnet member for an embedded magnet type rotating electrical machine, including a magnet portion, and the rotating electrical machine when the magnet portion is incorporated in the rotating electrical machine. There is provided a permanent magnet member having a shape of a cross section of the magnet portion in a plane perpendicular to the rotation axis and / or a shape in which the positional relationship of the cross section with respect to the rotation axis is continuously changed. The magnet portion is mainly used to form a static magnetic field for interacting with an alternating magnetic field generated in the stator side coil when the permanent magnet member is incorporated in the rotor of the rotating electrical machine. According to the present invention, the change in the static magnetic balance between the rotor and the stator without skewing the coils provided in the stator by changing the cross-sectional shape of the magnet portion in a plane perpendicular to the rotation axis of the rotating electrical machine. To reduce the cogging torque.

  In particular, it is preferable that the cross-sectional shape of the magnet part and / or the positional relationship of the cross-section with respect to the rotation axis change continuously from the viewpoint of magnet processing and cogging torque reduction. By changing continuously, the change of steep gap magnetic flux can be relieved, and the cogging torque can be reduced by moderately generating the force due to the sudden magnetic fluctuation. Here, continuously changing means that there is no region in which the cross-sectional shape or the like of the magnet portion does not change from one end to the other end in the rotation axis direction of the rotating electrical machine. Further, the positional relationship of the magnet cross section with respect to the rotation axis is changing, the position of the cross section with respect to the rotation axis may be changed in the radial direction, may be changed in the rotation direction of the rotating electrical machine, A combination thereof may also be used.

  In addition, the magnet part used for this invention is not specifically limited, Magnets, such as a rare earth, a ferrite, and alnico, can be used. In particular, a rare earth (Nd, Sm-based) sintered magnet is preferably used because of the energy product. Moreover, it is preferable that the magnet part used for this invention has the magnetization direction of a direction substantially parallel to the radial direction of a rotary electric machine, when it integrates in a rotary electric machine similarly to the conventional permanent magnet piece.

  Moreover, it is preferable that the shapes of the permanent magnet member and the magnet portion are rotationally symmetric with respect to the radial axis of the rotating electrical machine passing through the center of the permanent magnet member. In the case of rotational symmetry, the change in the magnetic flux generated by the magnet is the same with respect to the gap portion, so the change in cogging torque is gentle, whereas in the case of non-rotation symmetry, there is a difference in the amount of change in magnetic flux. There is a case. However, it is not necessarily required to be rotationally symmetric. For example, as will be described in detail below, when the magnet portion is in a shape having a slope or a shape to be skewed, only one side of the permanent magnet member is used. These shapes can also be used, and shapes that are not rotationally symmetric (for example, a slope and a skew can be combined) are also possible. That is, as will be described in detail below, the shape of the magnet part is from a substantially rectangular parallelepiped to a substantially triangular pyramid including at least one vertex of the substantially rectangular parallelepiped and / or a substantially triangular prism including at least one side of the substantially rectangular parallelepiped. It is preferable that at least one of the shapes is cut off.

[First reference form (no slope, no auxiliary part)]
Specifically, in the first reference form of the present invention, at least one substantially triangular pyramid including at least one vertex of the substantially rectangular parallelepiped is cut off from the substantially rectangular parallelepiped. The shape is preferred. In other words, it is preferable that the shape of the magnet portion is a shape obtained by cutting out a substantially triangular pyramid including at least a part of one of the sides parallel to the rotation axis of the rotating electrical machine from a substantially rectangular parallelepiped. In FIG. 1, the typical perspective view of the permanent magnet member concerning the form used as the 1st reference of this invention is shown. (A) shows the shape before cutting off, (b) shows the shape after cutting off. That is, as shown in FIG. 1, the permanent magnet member 10 according to the reference embodiment includes a magnet portion 1 having a shape obtained by cutting off two triangular pyramids 11 so as to be rotationally symmetric from a rectangular parallelepiped permanent magnet member. Have. Here, one of the triangular pyramids has two vertices A1 and B1 on a side parallel to the rotation axis of the rotating electrical machine and a vertex A1 substantially parallel to the magnetization direction of the magnet portion when incorporated in the rotating electrical machine. This is a triangular pyramid having four vertices, which are a vertex C1 other than the vertex A1 on the side to include and a point D1 on the side including the vertex A1 substantially parallel to the rotation direction of the rotating electrical machine. In the reference form, a point on the side including the vertex A1 parallel to the rotation axis of the rotating electrical machine can be selected instead of the vertex B1. Similarly, instead of the vertex C1, a point on the side including the vertex A1 that is substantially parallel to the magnetization direction of the magnet portion can be selected.

In this manner, the triangular pyramid including at least one apex of the substantially rectangular parallelepiped is cut off so that the corner of the magnet part has a slope, and the magnet cross-sectional shape in the rotation axis direction is continuously changing. By doing so, it is possible to relieve the steep location of the gap magnetic flux density distribution between the rotor and the stator, and thereby it is possible to significantly reduce the cogging torque of the rotor. That is, as described above, in the conventional permanent magnet type rotating electrical machine, the gap magnetic flux density between the stator and the rotor becomes trapezoid, and thus a large torque ripple is generated. However, according to the reference form, the magnetic flux distribution generated on the rotor surface can be brought close to a sine wave, and the cogging torque can be reduced. In addition, by forming the shape with the triangular pyramid cut off, the cogging torque can be reduced by shifting the static magnetic balance between the rotor and the stator, similarly to the shape to be skewed, which will be described later.

[Second reference form (skew, no auxiliary part)]
Further, in the second reference form of the present invention, the shape of the magnet portion is a shape obtained by cutting off at least one approximately triangular prism including at least one side of the approximately cuboid from the approximately cuboid. Is preferred. In other words, it is preferable that the shape of the magnet portion is a shape obtained by cutting out a substantially triangular prism including at least a part of one of surfaces substantially perpendicular to the rotation direction of the rotating electrical machine from a substantially rectangular parallelepiped. In FIG. 2, the typical perspective view of the permanent magnet member concerning the form used as the 2nd reference of this invention is shown. (A) shows the shape before cutting off, (b) shows the shape after cutting off. That is, as shown in FIG. 2, the permanent magnet member 10 according to the reference embodiment includes a magnet portion 1 having a shape obtained by cutting off two triangular prisms 12 so as to be rotationally symmetric from a rectangular parallelepiped permanent magnet member. . Here, one of the triangular prisms passes through the four vertices A2, B2, C2, and D2 and the vertex A2 or D2 on a surface substantially perpendicular to the rotation direction of the rotating electrical machine when incorporated in the rotating electrical machine. It is a triangular prism having points E2 and F2 on each of the other sides as six vertices. In the reference form, instead of the vertex B2, a point on the side including the vertex A2 parallel to the rotation axis of the rotating electrical machine can be selected. Similarly, instead of the vertex C2, a point on the side including the vertex D2 parallel to the rotation axis of the rotating electrical machine can be selected. In the reference form, the cross-sectional shape of the magnet is the same, but the position of the cross-section of the magnet is changed.

  In this way, the triangular shape including at least one side of the substantially rectangular parallelepiped is cut off so as to skew the corners of the magnet, and the positional relationship of the magnet cross section in the rotation axis direction with respect to the rotation axis continuously changes. By adopting such a shape, the static magnetic balance between the rotor and the stator can be shifted, thereby making it possible to significantly reduce the cogging torque of the rotor.

  In addition, according to the present invention, the output torque can be further improved while the cogging torque is reduced. That is, in the present invention, the cogging torque can be reduced by cutting off the triangular pyramid and the triangular prism, and the cogging torque is reduced by supplementing auxiliary materials such as auxiliary magnets while maintaining the skew effect. Further, the output torque can be improved.

  Here, the substantially rectangular parallelepiped is to be interpreted in the broadest sense and refers to a shape in which three sets of faces facing each other in parallel can be considered. Specifically, the substantially rectangular parallelepiped includes not only a rectangular column such as a rectangular parallelepiped or a cube but also a column having a D-shaped or C-shaped cross section. In addition, regarding the side or surface of the substantially rectangular parallelepiped, when it is (substantially) parallel or (substantially) perpendicular to the rotation axis, radial direction or rotational direction of the rotating electrical machine, or the magnetization direction of the magnet part, It should be noted that the surface is specified and may not be strictly parallel or perpendicular. In addition, regarding the shape of the magnet portion or the like, when “cut off” is used, this is not intended to limit the manufacturing method of the shape, but is used only for specifying the final shape of the object. Should. For example, a shape obtained by cutting out a substantially triangular pyramid from a substantially rectangular parallelepiped need not necessarily be formed by the step of cutting out a substantially triangular pyramid from a substantially rectangular parallelepiped, and the final shape conceptually cuts out a substantially triangular pyramid from a substantially rectangular parallelepiped. Any shape can be used.

  When the magnet portion is skewed, the skew angle θ (hereinafter also referred to as skew angle θ) is preferably determined as follows. That is, it is preferable that the magnet is angled so that the skew angle θ is ½ of the angle between the slots (slot pitch). As the skew angle increases, the cogging torque decreases in proportion to the angle. On the other hand, the output as a rotating electrical machine decreases as the angle increases, and the output generally takes a minimum value in 1/2 slot. Therefore, for example, if the number of slots is 30, the skew angle θ is 360 degrees / 30 slots / 2, and the optimum skew angle θ is 6 degrees.

Here, the skew angle θ refers to an angle representing the largest difference in the position of the rotor in the rotation direction of the surface to be cut off when the permanent magnet member is incorporated in the rotor. In the case of a permanent magnet member provided with a skew so as to be rotationally symmetric, a line connecting the center of the magnet cross section between the upper surface and the lower surface of the rotor means an angle in the rotation direction of the rotor. Specifically, in the reference form shown in FIG. 2, the skew angle θ is an angle representing the largest difference in rotational position of the cut surface (B2C2F2E2). (The size of B2E2 in the rotational direction expressed as an angle).

  More specifically, in a permanent magnet member provided with a skew so as to be rotationally symmetric, the skew angle can be determined as follows. In FIG. 3, the typical top view of the rotor incorporating the permanent magnet member concerning this invention is shown. FIG. 4 is a schematic perspective view of a rotor incorporating the permanent magnet member according to the present invention. 3 and 4, for convenience of explanation, only one of the slot 21 of the rotor 20 and the permanent magnet member 10 inserted into the slot 21 is shown. As shown in FIGS. 3 and 4, when the rotor is viewed from a direction parallel to the rotation axis, each of the center A3 of the upper surface 10a and the center B3 of the lower surface 10b of the magnet portion and the rotation of the rotor are shown. The angle of the line connecting the axis O can be set.

In this case, as shown in FIGS. 3 and 4, if the distance between the rotation axis O of the rotor and the center A3 of the upper surface of the permanent magnet member is r, the center A3 of the upper surface of the permanent magnet member and the center B3 of the lower surface of The distance in the rotation direction of the rotor is 2rsin (θ / 2). The angle φ of the magnet at that time is given by the following equation, where L is the length of the rotor in the rotation axis direction.
φ = tan ⁻¹ (2r / L × sin (θ / 2))
Thus, the shape of the triangular prism to be cut off can be obtained, and the magnet portion is processed so as to be skewed accordingly. In the above, the skew angle has been described by taking the second reference form as an example. Similarly, the shape of the magnet portion of the permanent magnet member according to the first reference form (that is, the triangular pyramid to be cut off) The size of the rotation direction) can be determined.

According to another reference embodiment of the present invention, there is provided a permanent magnet member for an embedded magnet type rotating electrical machine, including a magnet portion and an auxiliary portion having a magnetic characteristic different from that of the magnet portion. Is done. Here, the shape of the auxiliary portion is preferably the cut-off shape. Moreover, it is preferable to provide an auxiliary | assistant part in the said position cut off of the said magnet part. That is, it is preferable that the auxiliary portion is attached to the magnet portion so that the shape of the entire permanent magnet member becomes the original magnet shape (that is, a substantially rectangular parallelepiped shape). A permanent magnet member including such a magnet part and an auxiliary part can be incorporated in the rotating electrical machine according to the present invention. Thereby, as will be described in detail below, the cogging torque can be reduced without skewing the stator side, and the shape of the slot for incorporating the permanent magnet member can be changed to the shape of the permanent magnet member. Therefore, it is easy to manufacture the rotor and to incorporate the permanent magnet member into the rotor. Further, by providing an auxiliary portion and making the entire shape a substantially rectangular parallelepiped, it is possible to ensure ease of assembly and further improve output torque. In addition, when a magnetic material is used for the auxiliary portion, since the magnetic permeability is high, it is possible to configure a magnetic path on the magnetic circuit.

  The auxiliary portion having a magnetic characteristic different from that of the magnet portion may be either a magnetic material or a non-magnetic material. When a magnetic material is used, a magnet that is not magnetized may be used. When using an auxiliary part made of non-magnetic material (hereinafter also referred to as spacer), the material of the non-magnetic material is selected from the group consisting of resin (epoxy, polyimide silicone, vinyl chloride, etc.), bakelite, etc., or aluminum, SUS, etc. can do. When using an auxiliary part made of a magnetic material, the material of the magnetic material can be the same as that of the magnet part, and a material having a high magnetic permeability and a small iron loss (for example, a laminated silicon steel plate) is selected. Good. In the present specification, the magnetic characteristics include, in addition to the magnetic flux density, coercive force, and the like, the magnetization direction, whether or not it is magnetic, and whether or not it is magnetized. That is, an auxiliary part made of a magnet having a different magnetization direction, an auxiliary part made of a non-magnetic material, and an auxiliary part made of a non-magnetized magnetic material are also included in the auxiliary parts having magnetic properties different from those of the magnet part.

[Third reference form (skew, auxiliary part made of non-magnetic material)]
FIG. 5 shows a schematic perspective view of a permanent magnet member according to a third reference embodiment of the present invention. (A) shows the magnet part before attaching the auxiliary | assistant part which consists of nonmagnetic bodies, (b) shows the permanent magnet member after attaching the auxiliary | assistant part which consists of nonmagnetic bodies to a magnet part. As shown in FIG. 5, the permanent magnet member 10 according to the embodiment becomes the reference has a magnet unit 1 of the same shape and form as the second reference. Further, the permanent magnet member 10 according to the embodiment becomes the reference, so as to be rotationally symmetrical, the spacer 2 of the second identical shape triangular prism and which cut off in the form that can be used as a guide, the second reference embodiment In the same position as the position cut off. In addition, when using the auxiliary | assistant part which consists of nonmagnetic materials, it is especially preferable at the following points. That is, when the nonmagnetic material is used, the force attracted to the rotor by the magnetic force of the magnet is reduced, so that workability is improved when the magnet is inserted into the rotor. In addition, the resin auxiliary part is easy to process and there is no iron loss.

[ First Embodiment (Auxiliary Part Consisting of Skew and Magnetized Magnet)]
FIG. 6 shows a schematic perspective view of the permanent magnet member according to the first embodiment of the present invention. As shown in FIG. 6, the permanent magnet member 10 according to this embodiment has a magnet portion 1 having the same shape as that of the second reference embodiment. Further, the permanent magnet member 10 according to the embodiment is made of a magnet having the same shape as the triangular prism cut off in the second reference form so as to be rotationally symmetric and having a different magnetization direction from the magnet part. The auxiliary part 2 has the same position as the position cut off in the second reference form. Here, as shown by the arrows in the figure, the magnetization direction of the magnet portion is a direction substantially parallel to the radial direction of the rotating electrical machine when incorporated in the rotating electrical machine, and the magnetization direction of the auxiliary portion is a magnet. It is a direction perpendicular to the magnetization direction of the part and the rotation axis of the rotating electrical machine, and is directed from each auxiliary part to the magnet part.

As shown in FIG. 6, the cogging torque can also be reduced by joining magnets having different magnetization directions. Thereby, the magnetic flux of the radial direction of the rotary electric machine in the edge part of a permanent magnet member can be reduced, and the change of magnetic flux can be relieve | moderated. Further, as described above, by using the auxiliary portion made of magnets having different magnetization directions, the magnetic flux can be concentrated and the maximum magnetic flux density can be improved, thereby greatly reducing the cogging torque without greatly changing the output. It becomes possible. The magnetization direction of the auxiliary portion is not particularly limited as long as it is different from the magnetization direction of the magnet portion. However, the magnetization having a direction in which a Hullback type magnetic flux is concentrated is a junction having both vertical and lateral directions. The method is preferred. That is, when the magnetization direction of the magnet part is incorporated in the rotating electrical machine, it is a direction substantially parallel to the radial direction of the rotating electrical machine and directed toward the gap side, and the magnetization direction of the auxiliary part is It can be a direction perpendicular to the magnetization direction and the rotation axis of the rotating electrical machine and directed from each auxiliary portion to the magnet portion. Conversely, when the magnetization direction of the magnet part is incorporated in the rotating electrical machine, it is a direction substantially parallel to the radial direction of the rotating electrical machine and away from the gap side, and the magnetization direction of the auxiliary part is The direction of magnetization of the magnet part and the direction perpendicular to the rotation axis of the rotating electrical machine can be away from the magnet part from each auxiliary part. As shown in the first embodiment, even in the case of using magnets having different magnetization directions or magnetic characteristics, the direction of the rotation axis is the same as in the first reference embodiment of the present invention. A magnet piece that continuously changes the cross-sectional shape and the like of the magnet portion can be used.

[ Fourth Reference Form (Scue, Auxiliary Part Consisting of Non-Magnetized Magnet)]
As described above, when a magnetic material is used for the auxiliary portion, a magnet that is not magnetized may be used. That is, in the third reference form shown in FIG. 5, the auxiliary part made of a non-magnetic material is used. An auxiliary portion made of a magnet can also be used ( fourth reference form, not shown). In such a permanent magnet member, an auxiliary portion made of an unmagnetized magnet is joined to a magnet portion cut into a predetermined shape that is not magnetized, and a yoke is attached only to an area (magnet portion) that is desired to be magnetized. It can be manufactured by partially magnetizing with. Further, a permanent magnet member having a magnetized portion and an unmagnetized portion can be manufactured by joining an auxiliary portion made of an unmagnetized magnet to a magnet portion cut into a predetermined magnetized shape. it can. In this way, the magnet part and the auxiliary part are integrated, and the auxiliary part is not magnetized, in other words, without magnetizing the area of the permanent magnet member as the auxiliary part. In the embodiment in which the magnet part is provided by magnetizing only the region to be the magnet part, the same material can be used for the magnet part and the auxiliary part, resulting in a decrease in workability and an increase in temperature. It is possible to prevent the adhesive layer from being damaged due to a difference in expansion coefficient among members due to disturbances such as heat.

  In the manufacture of the magnet part and the auxiliary part, any method used for processing the permanent magnet can be used, and specifically, by a processing method such as inner and outer periphery polishing and wire cutting or water jet. Can be processed into a desired shape. In addition, as described above, when the auxiliary portion is joined to the magnet portion, a heat-resistant adhesive such as epoxy or silicone can be applied and adhered to the adhesive surface, and in addition, mechanical fastening or resin and resin It can also be hardened with a tape or the like.

  As described above, according to another aspect of the present invention, a magnet-embedded rotating electrical machine including the permanent magnet member is provided. FIG. 7 is a conceptual perspective view of a magnet-embedded rotating electrical machine according to the present invention. That is, the magnet-embedded rotating electrical machine according to the present invention includes a rotor 20 and a stator (not shown). The stator is provided with a plurality of coils 30 for forming a rotating magnetic field. As described above, according to the present invention, the coil or the like need not be skewed, but may be skewed. Since the stator can be the same as the conventional one, detailed description is omitted. The rotor 20 has a plurality of slots for inserting the permanent magnet members. In the drawing, the direction in which the permanent magnet member is inserted is indicated by an arrow. As will be described later, the permanent magnet member may have a shape in which a plurality of the permanent magnet members are arranged in the rotation axis direction. The shape of the slot can correspond to the permanent magnet member, that is, can be a substantially rectangular parallelepiped. The slot position, number, and other rotors can be the same as those in the prior art, and a detailed description thereof will be omitted.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the embodiments described below do not limit the present invention.

  An electric motor for driving a railway vehicle having a rated output of 140 kW, a rated current of 108 A, and a rated rotational speed of 2550 rpm, using a permanent magnet member according to the present invention (Example), and using a rectangular permanent magnet member ( The variation of the cogging torque in Comparative Example) was measured. In the experiment, a permanent magnet embedded type inner rotor motor having two magnets and two magnets was used. In the experiment, a Nd-Fe-B magnet N36UH (Br1.18T, coercive force iHc25000 Oe) manufactured by Shin-Etsu Chemical Co., Ltd., having a rectangular parallelepiped permanent length of about 200 × width of about 70 × thickness of about 20 mm. A magnet piece was used.

[ Reference Example 1 (skew, no auxiliary part)]
In FIG. 8, the schematic diagram of the permanent magnet member concerning the reference example 1 is shown. FIG. 8 shows the direction of magnetization of the magnet portion from the direction perpendicular to the paper surface. In Reference Example 1, as shown in FIG. 8, the permanent magnet member has a skewed shape in accordance with the second reference form. Specific sizes are shown in the figure.

[ Reference Example 2 (no slope, no auxiliary part)]
FIG. 9 ((a) plan view, (b) side view, (c) front view) shows a schematic diagram of a permanent magnet member according to Reference Example 2. FIG. FIG. 9A shows the direction of magnetization of the magnet portion from the direction perpendicular to the paper surface. In Reference Example 2, as shown in FIG. 9, the permanent magnet member has a shape having a slope according to the first embodiment. Specific sizes are shown in the figure.

[ Reference Example 3 (skew, no auxiliary part)]
In FIG. 10, the schematic diagram of the permanent magnet member concerning the reference example 3 is shown. FIG. 10 shows the direction of magnetization of the magnet section from the direction perpendicular to the paper surface. In Reference Example 3, as shown in FIG. 10, the permanent magnet member has a skewed shape in accordance with the second reference form. However, the length in the rotation axis direction of the rotor having the cut shape (triangular prism) was set to half the length in the rotation axis direction of the rotor of the permanent magnet member. Thereby, in the reference example 3, the magnet volume which decreases by providing the skew is reduced compared to the reference example 1. The specific size is shown in the figure.

[ Reference Example 4 (skew, auxiliary part made of non-magnetic material)]
In FIG. 11, the schematic diagram of the permanent magnet member concerning the reference example 4 is shown. FIG. 11 shows the direction of magnetization of the magnet portion from the direction perpendicular to the paper surface. In Reference Example 4, as shown in FIG. 11, the permanent magnet member is composed of a magnet part 1 and an auxiliary part 2. The magnet unit 1 is formed by cutting two triangular prisms from a rectangular parallelepiped permanent magnet piece so as to be rotationally symmetrical and arranging them in the direction of the rotation axis of the rotary motor. The size of the triangular prism to be cut off is shown in the figure. The auxiliary portion 2 has a shape corresponding to the cut-off shape and is made of a non-magnetic material (polyimide resin).

  The torque was measured by hanging a weight with a thread, connecting it to a rotor, and measuring the force with a load cell. Specifically, a string was attached to the rotating shaft, and a weight was attached to the string via a pulley. The cogging torque was measured by measuring the force applied to the load cell installed in the middle of the string while pulling the string with its own weight. The weight of the weight was 20 kg.

In FIG. 12, the result of the measurement of the cogging torque waveform in the reference examples 1 to 4 and the comparative example is shown. As can be seen from FIG. 12, according to the present invention, the cogging torque could be reduced.

Moreover, the motor torque characteristics at the time of rating in Reference Examples 1 and 4 and the Comparative Example were measured as follows. That is, the motor was connected to a dynamometer and adjusted so as to obtain a rated torque, and the torque pulsation of the dynamometer at this time was measured. The current value was 324A. In FIG. 13, the output torque waveform at the time of rating of the comparative example and the reference examples 1 and 4 is shown. This result shows that according to the present invention, the cogging torque can be reduced and the output torque can be further improved.

[Embodiment 5 (skew, auxiliary part made of magnetized magnet)]
Moreover, in Example 5, the permanent magnet member was made into the shape according to 1st embodiment (refer FIG. 6). That is, a permanent magnet member having a skewed magnet portion 1 according to the second reference form and an auxiliary portion 2 corresponding to the cut-off shape was used. As each auxiliary portion 2, a magnet magnetized in the lateral direction, that is, a magnet perpendicular to the magnetizing direction of the magnet portion 1 and perpendicular to the rotation axis direction of the rotor (the left-right direction in FIG. 11), A magnet magnetized in the direction toward part 1 (characteristics are the same as those of the magnet part) was used.

[ Reference Example 6 (skew, auxiliary part made of magnetic material)]
In FIG. 14, the typical perspective view of the permanent magnet member concerning the reference example 6 is shown. In Reference Example 6, a permanent magnet member similar to that in Example 5 was used except that silicon steel plate 50A470 was used as auxiliary part 2. Specific sizes are shown in the figure.

For Example 5 and Reference Example 6 , the cogging torque waveform was measured as in Reference Examples 1 to 4 above. FIG. 15 shows the results of measurement of cogging torque waveforms in Example 5, Reference Example 6 and Comparative Example. For Example 5 and Reference Example 6 , the motor torque characteristics at the time of rating were measured as in Reference Examples 1 and 2 except that the current value was 108A. FIG. 16 shows output torque waveforms at the time of rating in Example 5, Reference Example 6 and Comparative Example. As shown in FIG. 15, it can be seen that the cogging torque is further reduced in Example 5 and Reference Example 6 compared to the comparative example. Also, as shown in FIG. 16, compared to Example 5, in Reference Example 6 , the volume of the magnetized magnet is reduced, so that the output torque of the motor is also reduced. On the other hand, in the comparative example, the cogging torque is increased, but the output is also maximized. On the other hand, in the fifth embodiment, the effect of reducing the cogging torque can be obtained, and at the same time, the decrease in the output torque can be minimized. That is, as in the fifth embodiment, by using a magnet magnetized in the auxiliary portion, the cogging torque can be reduced without reducing the output torque, and a balanced motor can be obtained. . As described above, in Example 5 and Reference Example 6 , the cogging torque can be reduced, and particularly in Example 5, the decrease in the output torque can be further suppressed to be small, which is particularly practical. As described above, it is conceivable that the auxiliary portion is made of a nonmagnetic material or a soft magnetic material.

The typical perspective view of the permanent magnet member concerning the form used as the 1st reference of the present invention is shown. (A) shows the shape before cutting off, (b) shows the shape after cutting off. The typical perspective view of the permanent magnet member concerning the form used as the 2nd reference of the present invention is shown. (A) shows the shape before cutting off, (b) shows the shape after cutting off. The typical top view of the rotor incorporating the permanent magnet member concerning the present invention is shown. The typical perspective view of the rotor incorporating the permanent magnet member concerning the present invention is shown. The typical perspective view of the permanent magnet member concerning the form used as the 3rd reference of the present invention is shown. (A) shows the magnet part before attaching the auxiliary | assistant part which consists of nonmagnetic bodies, (b) shows the permanent magnet member after attaching the auxiliary | assistant part which consists of nonmagnetic bodies to a magnet part. The typical perspective view of the permanent magnet member concerning a first embodiment of the present invention is shown. 1 shows a conceptual perspective view of a magnet-embedded rotating electrical machine according to the present invention. The schematic diagram of the permanent magnet member concerning the reference example 1 is shown. The schematic diagram of the permanent magnet member concerning the reference example 2 is shown. The schematic diagram of the permanent magnet member concerning the reference example 3 is shown. The schematic diagram of the permanent magnet member concerning the reference example 4 is shown. The result of the measurement of the cogging torque waveform in the reference examples 1 to 4 and the comparative example is shown. The output torque waveform at the time of rating in Reference Examples 1 and 2 and the Comparative Example is shown. The typical perspective view of the permanent magnet member concerning the reference example 6 is shown. The measurement result of the cogging torque waveform in Example 5, Reference Example 6 and Comparative Example is shown. The output torque waveform at the time of rating in Example 5, Reference Example 6 and Comparative Example is shown.

Explanation of symbols

1: Magnet part 2: Auxiliary part 10: Permanent magnet member 10a: Upper surface of permanent magnet member 10b: Lower surface of permanent magnet member 11: Triangular pyramid 12 cut off: Triangular prism 20 cut off: Rotor 21: Slot 30: Coil

Claims (4)

A permanent magnet member for an embedded magnet type rotating electrical machine, including a magnet part, and when the magnet part is incorporated in the rotating electrical machine, a cross-section of the magnet part in a plane perpendicular to the rotation axis of the rotating electrical machine The shape and / or the position of the cross section relative to the rotational axis has a continuously changing shape, and the magnet portion has a shape in which a corner portion is cut off from a substantially rectangular parallelepiped, and is in the cut-off position. The permanent magnet member further includes an auxiliary portion having a magnetic characteristic different from that of the magnet portion and having the same shape as the cut-off corner portion, and the auxiliary portion is made of a magnet having a different magnetization direction from the magnet portion. . Wherein the shape of the magnet portion, the substantially rectangular parallelepiped permanent magnet member according to claim 1 substantially triangular prism comprising at least one side of said substantially rectangular at least one cut off shape. 2. The permanent magnet member according to claim 1 , wherein the shape of the magnet portion is a shape obtained by cutting off at least one substantially triangular pyramid including at least one vertex of the substantially rectangular parallelepiped from a substantially rectangular parallelepiped.   A magnet-embedded rotary electric machine comprising the permanent magnet member according to claim 1.

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