JP3871873B2 - Permanent magnet type rotor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a permanent magnet type rotor of a permanent magnet type rotating electrical machine configured by attaching a permanent magnet to a shaft.
[0002]
[Prior art]
As shown in FIG. 6, the permanent magnet type rotating electric machine has a permanent magnet type rotor 4 in which a plurality of permanent magnets 6 are arranged along the circumferential direction to form magnetic poles, and the armature coil on the armature 1 side is formed. 3 is a synchronous motor that generates a moving magnetic pole by energizing 3 and draws power by the attractive force of the permanent magnet type rotor 4 and the moving magnetic pole, and can maintain high operating efficiency by its operating principle. In FIG. 6, 2 is an iron core of the armature 1, 2 a is a slit for housing the armature coil 3, and 5 is a shaft of the permanent magnet type rotor 4.
[0003]
Recently, variable speed operation has been widely used in permanent magnet type motors, and its application has been promoted in the region of high speed and ultra high speed rotation. In such a permanent magnet type electric motor, there are two types of arrangement of the permanent magnet on the rotor, that is, a peripherally attached magnet type and an embedded magnet type. The peripherally attached magnet type has a simple manufacturing process, and can be applied to a magnet that is difficult to incorporate and magnetize, such as a large model, by attaching a magnetized magnet. However, when performing high-speed rotation, it is unsuitable for applications in which excessive centrifugal force works, and in this case, an embedded magnet type is used. The embedded magnet type is easy to perform field-weakening control that achieves constant output variable speed operation, which is also highly demanded in other applications such as electric vehicles, and the magnet operating point after magnetization is higher than that of the outer-pasted magnet type. There is an advantage that the output characteristics can be improved. For this reason, the use of an embedded magnet type is the mainstream, and attempts have been made to apply it to large models.
[0004]
By the way, as a magnet used in a permanent magnet type rotating electrical machine, a cast / sintered magnet having a high energy density contributes to an increase in motor output, but it is difficult to form a complicated shape from a sintering process or a hard and brittle property. Therefore, it can be molded only to the extent that the shape can be adjusted by grinding and polishing. Therefore, in view of cost, it is preferable to use a simple shape such as a rectangular parallelepiped.
[0005]
In general, embedded magnet type rotors cannot be made very small in order to embed magnets, and the rotor needs to be relatively large. In particular, when the above-mentioned rectangular parallelepiped magnet is adopted, the rotor outer shape required for that purpose is required. Is much larger and often struggles with the armature dimensions.
[0006]
In particular, recently, attempts have been made to reduce the cost by utilizing the salient pole structure of the embedded magnet type rotor, actively using the reluctance torque, and increasing the torque or reducing the amount of magnet used. It is also true that the trend is toward increasing the amount of iron core.
[0007]
[Problems to be solved by the invention]
Downsizing is an ever-changing theme for rotating electrical machines, and there is an increasing need to balance the conflicting demands with improved characteristics as much as possible.
[0008]
Here, in the above-described embedded magnet type, a magnet insertion groove is formed in the rotor in accordance with the number of poles and the magnet shape. The magnet insertion groove is usually formed by punching from a hoop of a thin magnetic steel sheet at the same time as the rotor shape by a punching press, and then forming a laminated body. Therefore, for applications with different numbers of poles, it is common to make new rotors punched and stacked in different shapes. Also, when the rotor is rotated up to high-speed rotation, such as in EV applications, induction induced in the armature coil by the magnetic flux from the viewpoint of limiting the breakdown voltage of the inverter element (switching element, smoothing capacitor, etc.) When it is necessary to reduce the voltage, a method is adopted in which the magnet shape is reduced, and therefore a rotor with a small magnet insertion groove is newly manufactured or a magnet with a low energy density is used. However, it is preferable that the same rotor and the same magnet can be used instead of arranging rotors suitable for each application, because this leads to cost reduction.
[0009]
That is, in an embedded magnet type rotor, there is a demand for an embedded magnet type rotor that can adopt means for achieving the contradictory requirements of improving characteristics and miniaturization as much as possible, and means for diverting the same magnet to the same rotor.
[0010]
The present invention has been made in view of the above, and can achieve the conflicting performance of improvement in characteristics and downsizing, and also has the same punching die and manufacturing process in response to the request for changing the number of poles and changing the magnetic flux. It is an object of the present invention to provide a permanent magnet type rotor that can share the same magnet and can use the same magnet and is advantageous in terms of cost.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is the same in which electromagnetic steel plate punches are laminated in the shaft direction, and a plurality of punched electromagnetic steel plates are punched at equal intervals along the circumferential direction. In a permanent magnet type rotor in which a magnet is inserted and held in all of the magnet insertion grooves and the magnetization directions of the magnets are all aligned in a substantially radial direction, the number of the magnet insertion grooves is at least 2 with respect to the number of poles. The gist is that only the magnets inserted and held in the magnet insertion grooves corresponding to the positions between the poles are reversed by dividing the magnetization direction into two parts . With this configuration, for example, when the number of poles is 2, the number of magnet insertion grooves is 6, and three magnet insertion grooves are assigned to each pole. By reducing the width of each magnet and increasing the number of magnets, the total amount of magnets can be increased, the magnet torque can be increased, and the magnet insertion groove is arranged on the outer peripheral side of the rotor. In addition, the magnet can be fully occupied, and the outer dimensions of the rotor can be reduced to reduce the size. Further, by alternately reversing the magnetization directions of adjacent magnets, for example, a 6-pole rotor can be formed.
[0012]
Further, all the magnetic flux of the magnet flows in the radial direction, and can effectively work on the magnet torque. Also, when it is necessary to adjust the magnetic flux downward, or when the magnet thickness and the height of the magnet insertion groove are half-sized, the magnet and magnetic block are overlapped to form the magnet insertion groove. By inserting the magnetic flux, it is possible to prevent an increase in the magnetic flux, prevent an increase in magnetic loss and an excessive induced voltage, and avoid the magnetic flux from being lowered more than necessary.
[0013]
On the other hand, a part of the magnetic flux generated from one magnetic pole part of the magnet whose magnetization direction is reversed in two parts flows into the other magnetic pole part of the same magnet, flows only in the rotor, and flows through the flowing magnetic circuit with a high magnetic flux. Will be placed under density. For this reason, the magnetic flux acting as torque is prevented from leaking to the adjacent magnetic pole, which indirectly contributes to torque generation.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
1 and 2 are diagrams showing a first embodiment of the present invention. In FIGS. 1 and 2 and the drawings showing the embodiments shown in FIG. 3 and subsequent figures, the same or equivalent members as in FIG. 6 are denoted by the same reference numerals as those in FIG. Omitted. In FIG. 1, the permanent magnet type rotor 4 </ b> A is formed by inserting magnets 6 into the magnet insertion grooves 8 after laminating electromagnetic steel plate blanks in the direction of the shaft 5. Reference numeral 7 denotes a block made of a magnet material (hereinafter referred to as a magnetic block), which will be described later. A plurality of magnet insertion grooves 8 are formed along the circumferential direction of the rotor, and the number of the magnet insertion grooves 8 is a minimum of twice the number of poles. 2A is provided with four magnet insertion grooves 8 for the two-pole rotor, and FIG. 2B is also a two-pole rotor, but has six magnet insertion grooves 8. The cross sections of the permanent magnet type rotors 4A and 4B provided and magnets 6 inserted in the respective magnet insertion grooves 8 are shown. Two magnet insertion grooves 8 are assigned to each pole of the permanent magnet type rotor 4A of FIG. 2A, and the magnetization directions of the magnets 6 are aligned as shown in FIG. Each magnetic pole is formed. Also, three magnet insertion grooves 8 are assigned to each pole of the permanent magnet type rotor 4B of FIG. 2B, and the magnetization directions of the magnets 6 are aligned as shown in FIG. Each magnetic pole is formed.
[0022]
Here, for example, FIG. 2 (a) and FIG. 2 (b) will be described in comparison. The magnet having the four magnet insertion grooves 8 arranged in the same outer dimensions is the same two-pole rotator. It can be seen that the occupation state of the magnet 6 is at the limit, and it is no longer allowed to increase the width w or the thickness t of the magnet 6 in order to increase the magnet amount. On the other hand, in the case where six magnet insertion grooves 8 are arranged, the magnet width is narrowed, but since the number is increased, the total amount of magnets can be increased and the magnet torque is increased. Since the magnet insertion groove 8 can be disposed on the outer peripheral side of the rotor, there is still room in the occupied state of the magnet 6, and the rotor outer diameter can be reduced to reduce the size. In other words, the contradictory performance of reducing the size and improving the characteristics of the rotating electrical machine can be achieved.
[0023]
Further, in the case of FIG. 2 (a), a permanent magnet type rotor having four poles can be formed by alternately reversing the magnetization directions of the magnets 6 existing in the adjacent magnet insertion grooves 8, and also in FIG. 2 (b). Similarly, a 6-pole permanent magnet rotor can be formed by alternately reversing the direction of magnetization. That is, it is possible to provide a rotating electric machine having the same rotor shape and different polarity. According to this, it can be seen that the rotor punching mold and the rotor manufacturing process can be shared, and the rotor shape is advantageous in terms of cost.
[0024]
A second embodiment of the present invention will be described. In the present embodiment, in the permanent magnet type rotor of the first embodiment, all the magnets are inserted into the magnet insertion grooves assigned to the poles, and the magnetization directions of the magnets are all aligned in the substantially radial direction. Yes. All the magnetic flux generated by the magnet flows in the radial direction, passes through the magnetic circuit that flows to the teeth of the stator through the gap formed by the permanent magnet type rotor and stator, and makes this magnetic flux work effectively on the magnet torque to the maximum. Can do.
[0025]
In addition, when the magnetic flux generated by the magnet (hereinafter referred to as magnet magnetic flux) increases the loss of the stator teeth or the core back, causing a temperature rise, or the magnetic flux is interlinked with the stator windings. Therefore, when the voltage induced between the coil terminals is maximized and the inverter element may be damaged, it is necessary to adjust the magnetic flux downward.
[0026]
Generally, in order to increase the magnet torque in order to increase the output of the rotating electrical machine, a magnet with a material having a high energy density (a high generated magnetic flux density) is used, or the magnetic flux tolerance of the stator core is increased by increasing the width of the magnet. This can be dealt with by increasing the magnetic flux as much as allowed, but in proportion to the output, the so-called armature reaction due to the current passed through the stator winding increases, and it is added to the magnet arranged in the permanent magnet type rotor. Demagnetization increases. For this reason, the thickness of the magnet of the permanent magnet type rotor is often increased in order to face the demagnetizing force while also increasing the magnetic flux. Therefore, in the permanent magnet type rotor adopting such a magnet size, in order to share the magnet, the magnet width is made the same, and accordingly, the magnet insertion groove allocated to one pole is increased, corresponding to the increase in output. The thickness can be shared by stacking a plurality of magnets.
[0027]
In FIG. 1, when the operating temperature of the rotating electrical machine is low and the magnet itself has a sufficient demagnetizing force resistance, or is originally applicable to a use with a small demagnetizing force, the magnet magnetic flux is adjusted downward for the above reasons, or The case where the magnet thickness and the height of the magnet insertion groove are half-dimensionally illustrated is particularly illustrated, and the magnetic block 7 is superimposed on the magnet in the thickness direction and inserted into the magnet insertion groove 8. . The effect is that in the former case, the magnet thickness is reduced to prevent an increase in magnetic flux and to prevent an increase in magnetic loss or an excessive induced voltage. In the latter case, the magnet and the iron core are mainly used. On the other hand, there is an air gap as a magnetic circuit between them to prevent the magnetic flux from decreasing more than necessary.
[0028]
Further, when it is necessary to further reduce the magnetic flux of the magnet, or when the magnetic demagnetization is strong and the magnet thickness of the dimension of the magnet insertion groove is required, this magnetic block can be dealt with by using a non-magnetic material. When the magnetic block is made of a magnetic material, the demagnetizing force is all applied to the magnet, but if it is non-magnetic, it is equally applied to this block, so the demagnetizing force applied to the magnet relaxes only the thickness ratio. Can do.
[0029]
FIG. 3 shows a third embodiment of the present invention. In the present embodiment, in the permanent magnet type rotor of the second embodiment, as shown in FIG. 3, only the magnet 9 existing in the magnet insertion groove located between the poles is divided into two magnetization directions. Is reversed. The permanent magnet type rotor 4C of the present embodiment is provided with a means for adjusting the magnetic flux downward for the reason described in the second embodiment. That is, a part Φ of the magnetic flux emitted from one magnetic pole part of the divided magnet 9 flows into the other magnetic pole part of the same magnet and does not flow into the stator side, but only flows through the stator. It does not contribute directly to the magnet torque. Further, a part of the magnetic flux passes through the magnetic circuit flowing to the stator side through the air gap, and works as magnet torque. However, since the former magnetic flux places its flowing magnetic circuit under a high magnetic flux density, there is an effect of preventing magnetic flux acting as torque from leaking to the adjacent magnetic pole. That is, it indirectly contributes to torque generation.
[0030]
In the method of forming the magnet divided into two, two magnets magnetized in a single direction can be inserted into the magnet insertion groove with their magnetization directions reversed, for example, FIG. 3 and FIG. As is clear from comparison of 2 (b), when magnetizing with the magnetizing device, the rotor magnetic pole facing the magnetizing yoke is shifted, that is, the magnet inserted in the magnet insertion groove corresponding to the gap between the yokes. By using the same magnetizing device, the permanent magnet type rotor of this configuration can be provided simply by making the centers of the two face each other. In this case, a buffer portion in a non-magnetized state exists between the two divided magnetic poles, which is lower than the amount of magnetic flux obtained when two magnets are used.
[0031]
FIG. 4 shows a fourth embodiment of the present invention. In the present embodiment, in the permanent magnet type rotor of the first embodiment, as shown in FIG. 4, all the magnets 6 are inserted into the magnet insertion grooves assigned to the poles, and Only the magnet 10 present in the magnet insertion groove located is arranged with its magnetization direction oriented in the circumferential direction. This effect is substantially the same as that of the third embodiment, but the magnetic flux Φ generated by the magnet 10 of the permanent magnet type rotor 4D of the present embodiment is applied to the magnetization circuit flowing only in the rotor under a high magnetic flux density. The magnetic flux acting as torque prevents the leakage of the magnetic flux acting as torque to the adjacent magnetic pole. That is, it indirectly contributes to torque generation. Such a method of applying magnet magnetization in the circumferential direction is not possible with rotor magnetization, and a magnet magnetized in the width direction in advance is inserted into a magnet insertion groove existing between the poles.
[0032]
Although not shown, the magnetic flux amount can be finely adjusted by dividing the magnet into a plurality of parts in the width direction and replacing a part thereof with a magnetic block. That is, the replaced magnetic block does not generate magnet magnetic flux, but merely forms a magnetic circuit so as not to interrupt the flow of the magnetic magnetic flux, so that the effect of apparently reducing the width of the magnet is added. Become. Further, by using a material with a low Curie temperature or a material with a large saturation magnetization temperature change, the magnetic flux amount can be adjusted by the rotor temperature. That is, since the magnetic loss of the stator core or the harmonic loss of the rotor is proportional to the magnetic flux, the Curie temperature is close to the temperature so that the temperature does not exceed the allowable limit so that the demagnetization resistance of the magnet is reduced. By using a magnetic block made of a magnetic material having a magnetic property, the magnetization of the magnetic block disappears at this temperature, and the magnetic flux generated by this magnet is greatly reduced, so that the magnetic flux contributing to the torque is transferred to the adjacent magnetic pole. The magnetic flux resulting from the loss can be reduced.
[0033]
A fifth embodiment of the present invention will be described. In the present embodiment, in the permanent magnet type rotor of the first embodiment, a part of the magnet insertion groove assigned to each pole is replaced with a magnet having different characteristics. The different characteristics generally refer to the energy density (saturation magnetic flux density) of the magnet, and the permanent magnet type rotor of the present embodiment adjusts the magnet magnetic flux amount downward as described in the second embodiment. It also comes with an effect that can be used. That is, the voltage induced between the coil terminals when the stator teeth or core back loss increases due to the magnetic flux generated by the magnet and temperature rise becomes a problem, or when the magnetic flux is interlinked with the stator windings. In order to prevent this, the total amount of magnet magnetic flux is adjusted. On the other hand, by using a magnet having a large energy density and in combination with the seventh embodiment described later, the total amount of magnet magnetic flux is adjusted, and the effects described in the seventh embodiment are also provided. It can also be made. The present embodiment is not different from the stator structure of the first embodiment, and only a part of the magnet is replaced. Therefore, it is not shown again here.
[0034]
A sixth embodiment of the present invention will be described. In this embodiment, in the permanent magnet type rotor of the fifth embodiment, magnets having different characteristics are used, in particular, magnets having different Curie temperatures. A magnet having a different Curie temperature is, for example, a combination in which the former has a Curie temperature near 300 degrees, while the latter exists near 700 degrees, such as an Sm-Co magnet for a Ne-Fc-B magnet. Means. A magnet having a high Curie temperature generally has a high coercive force, and the coercive force is hardly lowered by the temperature. However, the energy density tends to be low regardless of the magnet materials mentioned above.
[0035]
Permanent magnet type rotating electrical machines are designed and manufactured so that they can sufficiently withstand demagnetization during steady operation. For example, when a large current flows temporarily due to step-out or rotor lock, or suddenly exceeds the allowable limit. If the temperature rises excessively, the possibility of demagnetization exceeding the demagnetization resistance of the magnet increases. However, due to protection coordination with inverter control, the occurrence of such a phenomenon is extremely low. For this reason, increasing the magnet thickness will unnecessarily increase the amount of magnets, leading to downsizing of the rotating electrical machine. It will be contrary. Therefore, by using the necessary magnet dimensions during steady operation and replacing some of the magnets with magnets with a high Curie temperature, this magnet alone will not become inoperable at all even if it falls into the abnormal state described above. The magnet is not demagnetized at the minimum, the magnet magnetic flux is maintained and the magnet torque is generated without change. Thereby, also from a viewpoint of demagnetization protection, it is possible to provide a permanent magnet type rotor having both high torque and high output rotating electrical machine and operation protection. The present embodiment is not different from the rotor structure of the fifth embodiment, and only a part of the magnet is replaced. Therefore, it is not shown again here.
[0036]
A seventh embodiment of the present invention will be described. In this embodiment, in the permanent magnet type rotor of the first embodiment, a magnet is not inserted into a part of a magnet insertion groove assigned to each pole, and a hole is left as it is. The present embodiment constitutes a means for adjusting the magnetic flux downward for the reason described in the second embodiment. That is, the magnet magnetic flux amount is adjusted by not inserting the magnet into a part of the magnet insertion groove but leaving the magnet in a hole state. This hole is present as a barrier for preventing the magnetic flux from flowing only in the rotor as a leakage flux. However, if the material is a non-magnetic material, the holes may be filled. For example, a block made of a conductive material such as copper or aluminum can be inserted and used as a damper bar for suppressing torque fluctuations, or for adjusting the balance of the rotor. Further, by using together with the fifth embodiment, it is possible to obtain a damper bar effect or balance adjustment without greatly reducing the magnet torque. Note that this embodiment is not different from the rotor structure of the fifth embodiment, and the magnet insertion groove is simply left as a hole, so that it is not shown here again.
[0037]
FIG. 5 shows an eighth embodiment of the present invention. In this embodiment, in the permanent magnet type rotor of the first embodiment, as shown in FIG. 5, a magnetic block 7 is inserted into a magnet insertion groove located near the gap. As the torque of a rotating electrical machine, there are a magnet torque and a reluctance torque, and it has recently been realized to realize the torque characteristics of the rotating electrical machine by a combination thereof. For example, for applications that require torque characteristics with a wide variable speed range, such as HEV / EV, reluctance torque must be used, and magnet torque and reluctance torque can be realized at an arbitrary ratio. Is required to. The reluctance torque is a torque obtained by exciting a rotor core and generating a magnetic flux with a part of a current supplied to the stator winding, and generating the magnetic flux. The magnetic flux forms a magnetic circuit that flows in the vicinity of the rotor core. However, in the rotor of this configuration, the magnet insertion grooves are arranged in close contact with each other for the purpose of minimizing the leakage of magnet magnetic flux, so that the magnetic flux that generates reluctance torque cannot flow as it is.
[0038]
In the permanent magnet type rotor 4E of the present embodiment, a magnetic flux (hereinafter referred to as an excitation magnetic flux) Φr that causes reluctance torque flows by crushing the magnet insertion groove located near the gap by inserting the magnetic block 7. A magnetic circuit is held. That is, the exciting magnetic flux Φr is not interrupted by the magnet insertion groove in the vicinity of the gap, but passes through the magnetic block 7 having a high magnetic permeability and flows to the stator through the gap, so that a large reluctance torque can be expressed. .
[0039]
A ninth embodiment of the present invention will be described. This embodiment is a permanent magnet type rotor according to the eighth embodiment, in which the magnet insertion groove located in the vicinity of the gap is made of a magnetic material having a high saturation magnetic flux density, for example, an Fe—Co based metal material. The magnetic block is a magnetic block made of a laminated body such as a directional silicon steel strip having a high magnetic flux density and a high magnetic permeability. The exciting magnetic flux is secured by crushing the magnet insertion groove in the vicinity of the pole with a magnetic block, but the adjacent magnet insertion groove is close to that part in the magnetic circuit. The space is small compared to the circuit, and therefore the magnetic flux density is increased, and the amount of generation is limited. In order to increase the amount of magnetic flux, it is only necessary to increase the number of magnet insertion grooves filled with the magnetic block and widen the space for limiting the amount of magnetic flux. However, it leads to a decrease in the magnetic flux of the magnet and is not suitable for applications that also require magnet torque. In such a case, it is necessary to alleviate the magnetic saturation of the magnetic block filled in the magnetic block without increasing the magnet insertion groove filled with the magnetic block. The permanent magnet type rotor of the present embodiment is achieved by adopting a magnetic material having a high saturation magnetic flux density or a magnetic material having a high magnetic flux density and a high magnetic permeability as the magnetic block material. That is, it is possible to increase the reluctance torque without increasing the allowable magnetic flux amount of the magnetic block made of this magnetic material and lowering the magnet torque. The amount of increase in the excitation magnetic flux does not increase as much as the method of increasing the magnet insertion groove filled with the magnetic block described above, but it can still be expected to increase by several tens of percent. Note that this embodiment is not different from the rotor structure of the eighth embodiment, and merely specifies the material of the magnetic block, and is not shown here again.
[0040]
【The invention's effect】
As described above, according to the present invention , the number of magnet insertion grooves is at least twice the number of poles , and each magnet is reduced in width and increased in number so that the total magnet amount is reduced. In addition, the magnet torque is increased, and the magnet insertion groove is arranged on the outer periphery side of the rotor, so that the magnet can be occupied and the rotor outer dimension can be reduced. Therefore, it is possible to achieve both contradictory performances of improvement in characteristics and downsizing. Further, by alternately reversing the magnetization directions of adjacent magnets, the number of poles can be changed in a rotor shape in which the same magnet insertion groove is formed by punching. Therefore, the same punching die and manufacturing process can be shared for changing the number of poles, which is advantageous in terms of cost.
[0041]
In addition, all insert the magnets into the magnet insertion groove assigned to each pole, and in Rukoto align the magnetization direction of the magnet in all approximately radially, magnetic flux all flows radially, effectively to the magnet torque Can work and improve the properties.
[0042]
Further, the magnetic flux of only magnet is inserted and held in the magnet insertion groove corresponding to between the poles, in Rukoto to reverse the direction of magnetization in 2 divided, a magnet whose magnetization direction is inverted by two divided Flows only in the rotor and forms a magnetic circuit with a high magnetic flux density, which prevents the magnetic flux acting as torque from leaking to the adjacent magnetic pole and indirectly contributes to torque generation, thereby improving the characteristics. be able to.
[Brief description of the drawings]
FIG. 1 is a perspective view of a permanent magnet type rotor according to a first embodiment of the present invention.
FIG. 2 is a transverse sectional view of the permanent magnet type rotor according to the first embodiment.
FIG. 3 is a cross-sectional view of a permanent magnet type rotor according to a third embodiment of the present invention.
FIG. 4 is a cross-sectional view of a permanent magnet rotor according to a fourth embodiment of the present invention.
FIG. 5 is a cross-sectional view of a permanent magnet type rotor according to an eighth embodiment of the present invention.
FIG. 6 is a cross-sectional view of a conventional permanent magnet type rotating electric machine.
[Explanation of symbols]
4A to 4E Permanent magnet type rotor 5 Shaft 6 Magnet 7 Magnetic block 8 Magnet insertion groove 9 Magnet 10 in which the magnetization direction is reversed in two divisions Magnet with the magnetization direction arranged in the circumferential direction

Claims (1)

Laminating electromagnetic steel sheets punched in the shaft direction, a magnet was inserted and held in all the same magnet insertion groove in which a plurality of punched at regular intervals along the laminated electromagnetic steel sheets punched in the circumferential direction, and the magnet In the permanent magnet type rotor in which all the magnetization directions of the magnets are aligned substantially in the radial direction, the number of the magnet insertion grooves is at least twice the number of poles, and the magnet insertion grooves corresponding to the gaps between the poles A permanent magnet type rotor , wherein only the inserted and held magnets are reversed in magnetization direction by two divisions .

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