JP2015006107A - Motor and compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the problem that, in a conventional motor, a diffusion magnet cannot be used for a motor such as e.g., a large-sized motor employing a thick magnet, and sufficient demagnetization resistance cannot be obtained in the large-sized motor as a result.SOLUTION: The motor comprises a magnet 70 which is disposed in a rotor 14 so as to oppose a magnetic field generated from a coil fixed to a stator, and in which concentration distribution of a heavy rare-earth element at a center side is lower than at a surface side. The magnet 70 is formed by laminating two permanent magnets 71 and 72 each having thickness (t) equal to or less than 3 mm in a direction across the magnetic field.

Description

  The present invention relates to a motor including a stator to which a coil is fixed and a rotor in which a magnet is disposed, and a compressor including the motor.

  When a magnetic field (reverse magnetic field) generated by a coil is applied to the magnet during motor operation, the magnet is demagnetized and the magnetic force is reduced. Therefore, the magnet can contain a heavy rare earth element to increase the coercive force. ing. Particularly in recent years, in order to minimize the amount of heavy rare earth elements used, magnets in which heavy rare earth elements are diffused from the magnet surface (hereinafter also referred to as diffusion magnets) are used in motors. In this magnet, since the heavy rare earth element is diffused from the magnet surface, the concentration of the heavy rare earth element is high and the coercive force is high on the surface side of the magnet. On the other hand, the concentration of heavy rare earth elements is lower and the coercive force is lower on the center side of the magnet than on the surface side. Therefore, for example, in Patent Document 1, in order to improve the coercive force of the portion that is easily demagnetized, the diffusion magnet is disposed in the axial direction of the rotor so that the concentration of heavy rare earth element in the portion where the magnetic field (reverse magnetic field) is strong is increased. Laminated in the radial direction.

JP 2011-61902 A

  By the way, in a large motor used for a screw compressor, for example, high output torque and high demagnetization resistance are required, so that it is necessary to increase the thickness of the magnet (for example, 5 mm or more). However, in the diffusion magnet, if the magnet thickness is large, the heavy rare earth element does not sufficiently penetrate into the center side of the magnet, and the coercive force of the magnet is lowered. Therefore, there is a problem that a diffusion magnet cannot be used in a motor that uses a magnet having a large thickness. As a result, sufficient demagnetization resistance cannot be obtained with a large motor.

  Accordingly, an object of the present invention is to provide a motor that can improve the demagnetization resistance in a motor using a magnet having a large thickness, and a compressor including the motor.

  In order to solve the above-mentioned problems, the present inventors investigated the relationship between the thickness of the magnet in the diffusion magnet and the decrease in coercive force. As a result, when the thickness of the magnet is 3 mm or less, the coercive force of the magnet is hardly reduced, but when the thickness of the magnet exceeds 3 mm, the coercive force of the magnet is reduced and the present invention has been completed. .

  A motor according to a first aspect of the present invention is configured to face a stator, a rotor arranged rotatably with respect to the stator, a coil fixed to the stator and generating a magnetic field, and a magnetic field generated from the coil. In the motor provided with the magnet disposed on the rotor and having a heavy rare earth element concentration distribution lower on the center side than on the surface side, the magnet has a plurality of magnets each having a thickness of 3 mm or less intersecting the magnetic field. It is characterized by being laminated.

  A motor according to a second invention is the motor according to the first invention, wherein the magnet is manufactured by diffusing a heavy rare earth element from the surface.

  In this motor, the thickness of the heavy rare earth element concentration distribution is lower on the center side than on the surface side, that is, the magnet (diffusion magnet) manufactured by diffusing the heavy rare earth element from the surface is 3 mm or less. A plurality of magnets having a thickness of 3 mm or less are stacked. As a result, the entire thickness of the magnet can be increased without reducing the coercive force of the magnet. Therefore, for example, a diffusion magnet can be used for a motor that uses a magnet having a large thickness, such as a large motor, and the demagnetization resistance of the large motor can be improved.

  A motor according to a third invention is the motor according to the first or second invention, wherein the average concentration of heavy rare earth elements in the predetermined first magnet among the plurality of laminated magnets is higher than that of the first magnet. It is characterized by being higher than the average concentration of heavy rare earth elements in the second magnet disposed on the side opposite to the stator.

  In this motor, since a magnet having a high coercive force is arranged on the stator side where the magnetic field (reverse magnetic field) generated by the coil is strong, the demagnetization resistance of the entire magnet can be improved.

  A motor according to a fourth invention is the motor according to any one of the first to third inventions, wherein the heavy rare earth element includes at least one of dysprosium and terbium.

  In this motor, since the heavy rare earth element contains at least one of dysprosium and terbium, the coercive force of the magnet can be further improved.

  A motor according to a fifth aspect of the present invention is the motor according to any one of the first to fourth aspects, wherein the plurality of laminated magnets are fixed with an adhesive.

  In this motor, a plurality of laminated magnets are fixed with an adhesive, so that the magnets are not easily displaced.

  A compressor according to a sixth aspect of the invention includes the motor according to any one of the first to fifth aspects of the invention.

  In this compressor, the demagnetization resistance can be improved in a motor using a magnet having a large thickness, such as a large motor.

  A compressor according to a seventh aspect is the compressor according to the sixth aspect, wherein the compressor is a screw compressor or a scroll compressor.

  In this compressor, the demagnetization resistance can be improved in a screw compressor or a scroll compressor in which a motor using a magnet having a large thickness is used.

  As described above, according to the present invention, the following effects can be obtained.

  In the first and second inventions, the thickness of the magnet (diffusion magnet) having a heavy rare earth element concentration distribution lower on the center side than the surface side, that is, a magnet manufactured by diffusing the heavy rare earth element from the surface is 3 mm or less. In addition, a plurality of magnets having a thickness of 3 mm or less are stacked. As a result, the entire thickness of the magnet can be increased without reducing the coercive force of the magnet. Therefore, for example, a diffusion magnet can be used for a motor that uses a magnet having a large thickness, such as a large motor, and the demagnetization resistance of the large motor can be improved.

  In the third invention, since the magnet having a high coercive force is arranged on the stator side where the magnetic field (reverse magnetic field) generated by the coil is strong, the demagnetization resistance of the entire magnet can be improved.

  In the fourth invention, since the heavy rare earth element contains at least one of dysprosium and terbium, the coercive force of the magnet can be further improved.

  In the fifth invention, the magnets stacked in a plurality are fixed with an adhesive, so that the magnets are not easily displaced.

  In the sixth invention, the demagnetization resistance can be improved in a motor using a magnet having a large thickness, such as a large motor.

  In the seventh invention, the demagnetization resistance can be improved in a screw compressor or a scroll compressor in which a motor using a magnet having a large thickness is used.

It is sectional drawing of the compressor which concerns on embodiment of this invention. It is a top view which shows operation | movement of the compression mechanism shown in FIG. 1, Comprising: (a) shows a suction process, (b) shows a compression process, (c) shows a discharge process. It is the III-III sectional view taken on the line of the motor shown in FIG. FIG. 4 is an enlarged view of the rotor shown in FIG. 3. It is a graph which shows the relationship between the coercive force of a magnet, and a residual magnetic flux density. It is a graph which shows the relationship between the thickness of a magnet, and the fall of a coercive force. It is explanatory drawing explaining the preparation method of the sample for measuring the coercive force ratio of a magnet. It is a graph which shows the relationship between a demagnetizing current and a demagnetizing factor.

  Hereinafter, embodiments of a compressor according to the present invention will be described with reference to the drawings.

[Overall configuration of compressor]
The compressor 10 according to the present embodiment is a screw compressor. The compressor 10 is configured as a sealed type. As shown in FIG. 1, in the compressor 10, a compression mechanism 20 and a motor 12 that drives the compression mechanism 20 are accommodated in a metal casing 11. The compression mechanism 20 is connected to the motor 12 via the drive shaft 21. A low-pressure space S1 that introduces low-pressure gas refrigerant into the casing 11 from a heat source side heat exchanger or utilization side heat exchanger of a refrigerant circuit (not shown) and guides the low-pressure gas to the compression mechanism 20, and a compression mechanism A high-pressure space S2 into which the high-pressure gas refrigerant discharged from 20 flows is partitioned.

  The compression mechanism 20 includes a cylindrical wall 16 formed in the casing 11, one screw rotor 40 disposed in the cylindrical wall 16, and two gate rotors 50 (see FIG. 2) meshing with the screw rotor 40. I have.

  The screw rotor 40 is a metal member formed in a substantially cylindrical shape. The outer diameter of the screw rotor 40 is set slightly smaller than the inner diameter of the cylindrical wall 16, and the outer peripheral surface of the screw rotor 40 is configured to be in sliding contact with the inner peripheral surface of the cylindrical wall 16. A plurality (six in this embodiment) of spiral grooves 41 (see FIG. 2) extending spirally from one axial end to the other end of the screw rotor 40 are formed on the outer periphery of the screw rotor 40.

  The drive shaft 21 is inserted through the screw rotor 40. The rotor 14 of the motor 12 is connected to one end of the drive shaft 21, and the other end of the drive shaft 21 is inserted into the insertion hole 47 of the screw rotor 40. The screw rotor 40 and the drive shaft 21 are connected by a key 22. The drive shaft 21 is arranged coaxially with the screw rotor 40.

  In the compression mechanism 20, a space surrounded by the inner peripheral surface of the cylindrical wall 16, the spiral groove 41 of the screw rotor 40, and the gate 51 of the gate rotor 50 becomes the compression chamber 23. The spiral groove 41 of the screw rotor 40 is open to the low pressure space S1 at the suction side end, and this open part is the suction port 24 of the compression mechanism 20.

  The compressor 10 is provided with a slide valve (not shown). This slide valve is provided in a slide valve housing portion (not shown) in which the cylindrical wall 16 bulges radially outward at two locations in the circumferential direction. The slide valve is configured such that the inner surface forms part of the inner peripheral surface of the cylindrical wall 16 and is slidable in the axial direction of the cylindrical wall 16.

  The slide valve is formed with a discharge port (not shown) for communicating the compression chamber 23 and the high-pressure space S2. That is, the refrigerant compressed in the compression chamber 23 is discharged from the discharge port of the slide valve to the high pressure space S2. Further, the cylindrical wall 16 has an upstream end of a bypass passage for returning the refrigerant from the compression chamber 23 to the low pressure space S1, and the slide valve opens and closes the upstream end of the bypass passage to compress the compression mechanism 20. Adjust the capacity.

[Compressor operation]
As shown in FIG. 1, when the motor 12 is started in the compressor 10, the screw rotor 40 rotates as the drive shaft 21 rotates. As the screw rotor 40 rotates, the gate rotor 50 also rotates, and the compression mechanism 20 repeats the suction process, the compression process, and the discharge process. Here, the description will be given focusing on the compression chamber 23 shaded in FIG.

  In FIG. 2A, the compression chamber 23 shaded is in communication with the low pressure space S1. Further, the spiral groove 41 in which the compression chamber 23 is formed meshes with the gate 51 of the gate rotor 50 located on the lower side of FIG. When the screw rotor 40 rotates, the gate 51 relatively moves toward the end of the spiral groove 41, and the volume of the compression chamber 23 increases accordingly. As a result, the low-pressure gas refrigerant in the low-pressure space S1 is sucked into the compression chamber 23 through the suction port 24.

  When the screw rotor 40 further rotates, the state shown in FIG. In FIG.2 (b), the compression chamber 23 which attached the mesh is in the closed state. That is, the spiral groove 41 in which the compression chamber 23 is formed meshes with the gate 51 of the gate rotor 50 located on the upper side in FIG. 2B and is partitioned from the low pressure space S1 by the gate 51. When the gate 51 moves toward the end of the spiral groove 41 as the screw rotor 40 rotates, the volume of the compression chamber 23 gradually decreases. As a result, the gas refrigerant in the compression chamber 23 is compressed.

  When the screw rotor 40 further rotates, the state shown in FIG. In FIG. 2 (c), the shaded compression chamber 23 is in communication with the high-pressure space S2 through a discharge port (not shown). When the gate 51 moves toward the end of the spiral groove 41 as the screw rotor 40 rotates, the compressed refrigerant gas is pushed out from the compression chamber 23 to the high-pressure space S2.

[motor]
Next, the motor 12 of the compressor 10 will be described in detail. As shown in FIGS. 1 and 3, the motor 12 includes a stator 13 and a rotor 14 disposed so as to be rotatable with respect to the stator 13.

  The stator 13 is substantially cylindrical, and is fixed to the inner peripheral surface of the casing 11 in the low-pressure space S1. The stator 13 is made of, for example, a plurality of laminated electromagnetic steel plates. As shown in FIG. 3, the stator 13 includes an annular back yoke portion 17 and a plurality of tooth portions 18 protruding radially inward from the inner peripheral surface of the back yoke portion 17. A plurality of coils 15 for generating a magnetic field are fixed to the stator 13. This coil 15 is a so-called distributed winding coil, and is fixed between adjacent tooth portions 18. Further, a core cut portion 13 a is formed on the outer peripheral surface of the stator 13, with a part thereof being cut out. The core cut part 13a constitutes a flow passage through which a low-pressure gas refrigerant is circulated.

  The rotor 14 is substantially cylindrical and is disposed inside the stator 13. As shown in FIG. 4, one end of the drive shaft 21 is connected to the inside of the rotor 14, and the drive shaft 21 is configured to rotate around the rotation axis X (see FIG. 1) together with the rotor 14. . The rotor 14 is made of, for example, a plurality of laminated electromagnetic steel plates.

  The rotor 14 is formed with four substantially rectangular slots 61 penetrating in the vertical direction. Each slot 61 includes a magnet insertion portion 62 and a short-circuit prevention portion 63 that extends from both circumferential ends of the magnet insertion portion 62 to the outer peripheral surface side of the rotor 14. The openings on the upper and lower sides of the slot 61 are closed by end plates (not shown). The four magnet insertion portions 62 are formed so that the straight lines connecting the respective center positions in the longitudinal direction and the rotation center are radial directions, and the extension lines of the magnet insertion portions 62 adjacent in the circumferential direction are orthogonal to each other. ing.

  Magnets 70 are inserted (arranged) in the magnet insertion portions 62 of the slots 61. The magnet 70 includes two permanent magnets 71 and 72. The two permanent magnets 71 and 72 each have a thickness t of 3 mm or less. Further, as shown in FIG. 4, the two permanent magnets 71 and 72 are arranged in a state of being stacked in the radial direction in each of the slots 61. Therefore, the two permanent magnets 71 and 72 are both arranged so that the end faces in the thickness direction face (intersect) the magnetic field generated from the coil 15. The permanent magnets 71 and 72 inserted through the slots 61 are fixed with an adhesive (for example, varnish).

  The two permanent magnets 71 and 72 arranged in each slot 61 are magnets (diffusion magnets) manufactured by diffusing heavy rare earth elements from the magnet surface. Therefore, in the permanent magnets 71 and 72, the concentration distribution of heavy rare earth elements is lower on the center side than on the surface side. As the heavy rare earth element, at least one of dysprosium (Dy) and terbium (Tb) is used. As shown in FIG. 5, in the magnet in which dysprosium (Dy) is diffused, the coercive force is improved as compared with the conventional permanent magnet. Further, in the magnet in which terbium (Tb) is diffused, the coercive force is further improved as compared with the magnet in which dysprosium (Dy) is diffused. On the other hand, as the content of dysprosium (Dy) and terbium (Tb) increases, the residual magnetic flux density decreases and the cost of the magnet increases.

  Since the permanent magnets 71 and 72 have a thickness t of 3 mm or less per piece, when the heavy rare earth element is diffused from the magnet surface of the permanent magnets 71 and 72, the heavy rare earth element is formed on the permanent magnets 71 and 72. It penetrates to the center side. Therefore, in these permanent magnets 71 and 72, the concentration distribution of heavy rare earth elements has almost no difference between the surface side and the center side (the concentration on the center side is slightly low). Therefore, the difference in coercivity between the surface side and the center side of the permanent magnets 71 and 72 is small, and the magnet as a whole has a high coercivity.

  In each slot 61, the average concentration of the heavy rare earth element in the first magnet 71 arranged on the radially outer side (stator side) of the permanent magnets 71 and 72 is radially inner than the first magnet 71 ( The average concentration of heavy rare earth elements in the second magnet 72 disposed on the side opposite to the stator is set higher. Therefore, since a magnet having a high coercive force is disposed on the stator side where the magnetic field (reverse magnetic field) generated by the coil 15 is strong, the demagnetization resistance of the entire magnet 70 is improved.

[Example]
[Example 1]
Next, the relationship between the magnet thickness t and the decrease in coercive force in the permanent magnets 71 and 72 used in the motor 12 will be described with reference to FIG.

  Using a plurality of samples having different magnet thicknesses t, the relationship between the magnet thickness t and the reduction in coercivity (coercivity ratio) was investigated. Here, the coercive force ratio refers to the ratio of the coercive force on the magnet center side to the average coercive force of the magnet, and means that the coercive force of the magnet decreases as this ratio decreases.

  Each sample is a diffusion magnet manufactured by diffusing heavy rare earth elements from the magnet surface, and each sample is the same except that the thickness t of the magnet is different. Therefore, the diffusion amount and diffusion method of heavy rare earth elements are the same.

  Here, as shown in FIG. 7A, the average coercive force is measured by cutting a sample in which a heavy rare earth element is diffused into Lmm squares and measuring magnetic characteristics. Further, the coercive force on the magnet center side is such that the sample in which the heavy rare earth element is diffused is cut into Lmm squares, and both end surfaces of the magnet are set so that the thickness of the magnet becomes a predetermined inspection thickness Xmm leaving the center side of the magnet. Polish from the side. And it measures by measuring the magnetic characteristic of the magnet which cut to Lmm square and was ground. For example, as shown in FIG. 7B, when a sample having a magnet thickness t of Ymm is used, the sample is polished from both end surfaces in the thickness direction (the hatched portion in FIG. 7B is polished). The magnet thickness is set to a predetermined inspection thickness X mm, and the magnetic properties are measured.

  As shown in FIG. 6, when the magnet thickness t is 3 mm or less, there is almost no difference in the coercive force ratio (the ratio of the coercive force on the magnet center side to the average coercive force). Therefore, in a permanent magnet having a magnet thickness t of 3 mm or less, the concentration distribution of heavy rare earth elements is hardly different between the surface side and the center side, and the magnet as a whole has a high coercive force. On the other hand, when the magnet thickness t exceeds 3 mm, a difference occurs in the coercive force ratio. For example, when the magnet thickness t is 5 mm, the coercive force ratio is reduced, and when the magnet thickness t is 7.5 mm, the coercive force ratio is extremely reduced. Therefore, in a permanent magnet having a magnet thickness t exceeding 3 mm, a large difference occurs in the concentration distribution of heavy rare earth elements on the surface side and the center side, and the coercive force of the entire magnet is lowered.

[Example 2]
Next, the relationship between the demagnetizing current and the demagnetizing factor will be described with reference to FIG. Here, the demagnetizing current means a current that acts in the direction of decreasing the magnetic force of the permanent magnet. Here, it is preferable that the motor can maintain a state in which the demagnetization rate is high (the magnetic force of the permanent magnet is difficult to decrease) even when the demagnetization current is large.

  The motor used in the example has the same configuration as the motor 12 described in the present embodiment, and each slot 61 has a diffusion magnet having a magnet thickness t (for example, t = 3 mm). Two sheets are laminated in the radial direction. On the other hand, in the motor used in the comparative example, each slot 61 has a single magnet having a thickness of 2t (for example, 2t = 6 mm). The comparative example is different from the example in the above points, and is the same as the example in other points.

  In the motor of the embodiment, since the thickness t of the magnet used is 3 mm or less, the coercive force is high as shown in FIG. Therefore, even when a target demagnetizing current (target value A shown in FIG. 8) is passed, the demagnetization rate hardly decreased as shown in FIG. That is, the motor of the example is less likely to demagnetize the permanent magnet even when used in a compressor in which a large demagnetizing current flows, such as the compressor 10 (screw compressor) of the present embodiment. On the other hand, in the motor of the comparative example, since the thickness t of the magnet used is larger than 3 mm, the coercive force is low as shown in FIG. For this reason, as shown in FIG. 8, the demagnetization factor is greatly reduced at a demagnetizing current equal to or less than the target demagnetizing current (target value A shown in FIG. 8). That is, when the motor of the comparative example is used for a compressor in which a large demagnetizing current flows, the permanent magnet is greatly demagnetized.

[Features of motor and compressor of this embodiment]
The motor 12 and the compressor 10 of this embodiment have the following characteristics.

  In the motor 12 of this embodiment, the thickness t of a magnet (diffusion magnet) having a heavy rare earth element concentration distribution lower on the center side than the surface side, that is, a magnet (diffusion magnet) manufactured by diffusing the heavy rare earth element from the surface is 3 mm or less. A plurality of magnets 70 having a thickness t of 3 mm or less are stacked. As a result, the entire thickness of the magnet 70 can be increased without reducing the coercive force of the magnet 70. Therefore, for example, a diffusion magnet can be used for a motor that uses a magnet having a large thickness, such as a large motor, and the demagnetization resistance of the large motor can be improved.

  Further, in the motor 12 of this embodiment, the coercive force is higher on the stator 13 side where the magnetic field (reverse magnetic field) generated by the coil 15 is stronger than the second magnet 72 disposed on the opposite side of the stator 13. Since one magnet 71 is arranged, the demagnetization resistance of the entire magnet 70 can be improved.

  Moreover, in the motor 12 of this embodiment, since the heavy rare earth element contains at least one of dysprosium and terbium, the coercive force of the magnet 70 can be further improved.

  Moreover, in the motor 12 of this embodiment, since the permanent magnets 71 and 72 (multiple laminated magnets) are being fixed with the adhesive agent, magnets are hard to shift | deviate.

  Further, in the motor 12 of the present embodiment, the demagnetization resistance can be improved in a motor using a magnet having a large thickness, such as a large motor.

  Further, in the motor 12 of the present embodiment, the demagnetization resistance can be improved in a screw compressor in which a motor using a magnet having a large thickness is used.

  Although the embodiments of the present invention have been described above, it should be considered that the specific configuration of the present invention is not limited to the first and second embodiments. The scope of the present invention is shown not only by the description of the above-described embodiment but also by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope. Note that the following modifications can be implemented in combination as appropriate.

[Modification]
In the above embodiment, the magnet 70 is a laminate of two permanent magnets 71 and 72 in each slot 61, but may be a laminate of three or more permanent magnets.

  Moreover, in the said embodiment, although the magnet 70 and the magnet insertion part 62 of the slot 61 are rectangular in planar view, it is not restricted to it. For example, the magnet insertion portion of the magnet and the slot in a plan view may have a curved shape along the outer peripheral surface of the rotor 14.

  Moreover, in the said embodiment, although the magnet 70 is penetrated by the magnet insertion part 62 of the slot 61, it is not restricted to it. For example, a magnet may be disposed (fixed) on the outer peripheral surface of the rotor 14.

  In the embodiment described above, the four slots 61 are formed in the rotor 14, but the number of slots is not limited thereto, and may be two or six, for example.

  Further, in the above embodiment, the average concentration of heavy rare earth elements in the first magnet 71 arranged on the radially outer side (stator side) of the permanent magnets 71 and 72 is radially inner (stator) than the first magnet 71. Higher than the average concentration of heavy rare earth elements in the second magnet 72 disposed on the opposite side. However, the average concentration of the heavy rare earth element in the predetermined first magnet among the plurality of laminated magnets is higher than the average concentration of the heavy rare earth element in the second magnet arranged on the opposite side of the stator from the first magnet. Should be included. Therefore, for example, when three permanent magnets are stacked in each slot 61, the average concentration of heavy rare earth elements in the permanent magnet arranged in the middle of the three permanent magnets is on the opposite side of the stator. It may be higher than the average concentration of heavy rare earth elements in the permanent magnet.

  Moreover, in the said embodiment, the average concentration of the heavy rare earth element in the 1st magnet 71 arrange | positioned at the stator side among the permanent magnets 71 and 72 is 2nd arrange | positioned on the opposite side to a stator rather than the 1st magnet 71. Although higher than the average concentration of heavy rare earth elements in the magnet 72, it may be the same.

  In the above embodiment, the heavy rare earth element diffused into the magnet 70 includes at least one of dysprosium and terbium, but is not limited thereto. For example, the heavy rare earth element diffused into the magnet 70 may be holmium (Ho).

  Moreover, in the said embodiment, although permanent magnets 71 and 72 are fixed with an adhesive agent, the fixing method is not restricted to an adhesive agent.

  Moreover, in the said embodiment, although the winding system of the coil 15 fixed to the stator 13 is what is called distributed winding, even if the winding system of a coil is what is called concentrated winding which winds a coil to the tooth | gear part of a stator. Good.

  Moreover, in the said embodiment, although this invention was applied to the motor 12 by which the rotor 14 is arrange | positioned inside the stator 13, you may apply this invention to the motor by which a rotor is arrange | positioned outside the stator.

  Moreover, in the said embodiment, although the compressor 10 is a screw compressor, although the thickness of a magnet is small compared with a screw compressor, it is a compressor which needs to enlarge the thickness of a magnet (for example, 5 mm or more). The present invention may be applied to a scroll compressor. Thereby, in the scroll compressor which is a compressor which needs to enlarge the thickness of a magnet, a demagnetization proof stress can be improved. The present invention can also be applied to a rotary compressor.

  By using the present invention, the demagnetization resistance can be improved in a motor using a magnet having a large thickness.

10 Compressor 12 Motor 13 Stator 14 Rotor 15 Coil 70 Magnet 71 First Magnet 72 Second Magnet

Claims (7)

A stator,
A rotor arranged rotatably with respect to the stator;
A coil fixed to the stator and generating a magnetic field;
In a motor provided with a magnet disposed on the rotor so as to face a magnetic field generated from the coil and having a concentration distribution of heavy rare earth elements lower on the center side than on the surface side,
The magnet
A motor comprising a plurality of magnets each having a thickness of 3 mm or less stacked in a direction intersecting with a magnetic field. The magnet
The motor according to claim 1, wherein the motor is manufactured by diffusing heavy rare earth elements from the surface.   The average concentration of heavy rare earth elements in a predetermined first magnet among the plurality of stacked magnets is higher than the average concentration of heavy rare earth elements in a second magnet disposed on the opposite side of the stator from the first magnet. The motor according to claim 1 or 2, characterized by the above-mentioned.   The motor according to claim 1, wherein the heavy rare earth element includes at least one of dysprosium and terbium.   The motor according to any one of claims 1 to 4, wherein the plurality of laminated magnets are fixed with an adhesive.   A compressor comprising the motor according to claim 1.   The compressor according to claim 6, wherein the compressor is a screw compressor or a scroll compressor.

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