JP2011061902A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor whose efficiency is improved by increasing demagnetization resistance. <P>SOLUTION: The electric motor 3 includes a stator 8, a rotor 9, a coil 38 fixed to the stator 8, and magnets 35, 36 fixed to the rotor 9. The magnets 35, 36 are manufactured by diffusing a heavy rare earth element from the surface of a base material. The heavy rare earth element is located mostly in a position I facing a portion where the distribution of a magnetic field generated from the coil 38 is strong. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric motor in which a magnet is installed on a rotor.

  Conventionally, various electric motors have been developed in which a coil for generating a magnetic field is disposed on the stator side and a plurality of permanent magnets are disposed on the rotor side so as to face the coil. One permanent magnet is inserted into each slit formed in the motor rotor at regular intervals in the circumferential direction.

  Here, in developing a high-efficiency DC motor, a high-performance magnet is used as one of the means for improving the efficiency. One of the techniques for producing high-performance magnets recently is to increase the coercive force by the grain boundary diffusion technology of dysprosium (Dy) and terbium (Tb), but the grain boundary diffusion technology applies heavy rare earth to the magnet surface. In order to diffuse from the surface, however, the deeper the depth, the smaller the amount of heavy rare earth diffused and the lower the coercive force.

  Therefore, when used for a motor, there is a problem in that the coercive force cannot be sufficiently increased because it is not easily diffused in the central portion of the magnet that requires the most coercive force.

  Conventionally, a magnet is manufactured by applying heavy rare earth to the magnet surface and diffusing from the surface by diffusing the grain boundary, and the motor is constituted by one magnet per slot of the motor rotor. .

  In addition, in the electric motors described in Patent Document 1 (Japanese Patent Laid-Open No. 2003-70214) and Patent Document 2 (Japanese Patent Laid-Open No. 2002-262490), a normal permanent magnet in which heavy rare earth is not grain boundary diffused is used. Although there was a structure in which it was divided and inserted into the slit of the rotor core to reduce eddy current loss, a magnet in which heavy rare earth was diffused was not adopted, and naturally the distribution of the diffusion amount was not taken into consideration.

  At the time of magnet grain boundary diffusion, heavy rare earth is diffused from the surface of the base material, so the heavy rare earth is sufficiently diffused in the portion near the side surface of the base material, but the diffusion amount as it enters the inside from the side surface of the base material Accordingly, the coercive force of the magnet decreases accordingly.

  As a portion that is easily demagnetized in an electric motor, both side surfaces of the magnet are easily demagnetized in the width direction, and a central portion in the axial direction is easily demagnetized. For this reason, there is a problem in that it cannot be sufficiently diffused in the central portion where it is easy to demagnetize in the axial direction.

  As a countermeasure for this, it is necessary to use a magnet having a high coercive force of the material. However, if the coercive force of the material of the magnet is increased, the magnetic flux density (Br) of the material is decreased, and the efficiency of the motor is decreased. .

  An object of the present invention is to provide an electric motor in which the efficiency of the electric motor is improved by increasing the resistance to demagnetization.

  The electric motor of the first invention includes a stator, a rotor, a coil, and a magnet. The stator is fixed to an attachment target. The rotor is rotatably arranged with respect to the stator. The coil is fixed to the stator and generates a magnetic field. The magnet is fixed to the rotor and arranged to face the magnetic field generated from the coil. Magnets are manufactured by diffusing heavy rare earth elements from the surface of a substrate. The heavy rare earth elements are concentrated at opposing positions that face portions where the distribution of the magnetic field generated from the coil is strong.

  Here, the magnet is manufactured by diffusing heavy rare earth elements from the surface of the base material, and the heavy rare earth elements are concentrated at the opposed positions facing the portion where the magnetic field distribution generated from the coil is strong. It is possible to improve the coercivity of the portion that is easy to do. As a result, the efficiency of the electric motor is improved by increasing the resistance to demagnetization.

  Regarding the influence on the change in the stator thickness, the thinner the thickness, the smaller the range of the portion where the magnetic field distribution is strong. For this reason, the ratio of the opposing positions facing the portion where the magnetic field distribution is strong increases, so that the effect of concentrating heavy rare earth elements at the opposing positions is increased.

  The electric motor of the second invention is the electric motor of the first invention, and a plurality of magnets are arranged so as to face the magnetic field generated from the coil. At least two of the plurality of magnets are arranged so that a part of their peripheral end faces is located at the opposing position.

  Here, paying attention to the region where the diffusion amount of heavy rare earth elements is large on the peripheral end surface of the magnet, at least two of the plurality of magnets have a part of their peripheral end surfaces in the facing position. It is arranged to be located. Thereby, the coercive force of the part which is easy to demagnetize can be improved by arrangement | positioning of a some magnet.

  The electric motor according to a third aspect is the electric motor according to the second aspect, wherein at least two magnets are arranged side by side in the rotation axis direction of the rotor.

  Here, since at least two magnets are arranged side by side in the direction of the rotation axis of the rotor, the coercive force of the portion most easily demagnetized in the direction of the rotation axis of the rotor can be improved.

  The electric motor according to a fourth aspect is the electric motor according to the second aspect or the third aspect, wherein at least two magnets are arranged side by side in the radial direction of the rotor.

  Here, since at least two magnets are arranged side by side in the radial direction of the rotor, it is possible to arrange more circumferential end surfaces of magnets with a large amount of diffusion of heavy rare earth elements in opposed positions, thereby It is possible to further improve the coercivity of the portion that is easily demagnetized.

  The electric motor of the fifth invention is the electric motor of the first invention or the second invention, and the magnet has a concave portion and / or a convex portion on a surface facing the coil. The concave portion and / or the convex portion are arranged so as to be located at the opposing positions.

  Here, since the concave portion and / or the convex portion formed on the surface of the magnet facing the coil are located at the facing position, the surface area of the magnet is partially enlarged to increase the heavy rare earth element around the concave and convex portions. Can be increased, and the coercive force of the portion that is easily demagnetized can be improved.

  A compressor according to a sixth aspect of the invention includes a sealed cylindrical casing and the electric motor according to any one of the first to fifth aspects of the invention. The electric motor is stored in the casing in a state where the stator is fixed to the inner wall of the casing.

  Here, the magnet of the electric motor stored in the compressor is manufactured by diffusing heavy rare earth elements from the surface of the base material, and the heavy rare earth elements are opposed to the portion where the distribution of the magnetic field generated from the coil is strong. Since it concentrates on the coercive force, the coercive force of the portion that is easily demagnetized can be improved. In addition, the efficiency of the compressor can be improved.

  According to the first invention, it is possible to improve the coercivity of a portion that is easily demagnetized. As a result, the efficiency of the electric motor is improved by increasing the resistance to demagnetization.

  According to the second aspect of the present invention, the coercivity of the portion that is easily demagnetized can be improved by the arrangement of the plurality of magnets.

  According to the third invention, it is possible to improve the coercive force of the portion that is most likely to be demagnetized in the rotation axis direction of the rotor.

  According to the fourth aspect of the present invention, the coercive force of the portion at the opposite position where the demagnetization is likely can be further improved by arranging a large number of magnets in the axial direction and the radial direction of the rotor.

  According to the fifth aspect, the coercivity of the portion that is likely to be demagnetized by the unevenness formed in the magnet can be improved.

  According to the sixth aspect of the invention, the coercive force of the portion of the electric motor that is likely to be demagnetized can be improved, and as a result, the efficiency of the compressor can also be improved.

1 is a longitudinal sectional view of a hermetic compressor including an electric motor according to an embodiment of the present invention. II-II sectional view taken on the line of the hermetic compressor of FIG. FIG. 2 is an enlarged longitudinal sectional view showing the arrangement of two divided magnets on the rotor side of the electric motor of FIG. 1. 1A is a front view, FIG. 1B is a side view, FIG. 1C is a sectional view in the width direction, and FIG. 1D is a sectional view in the thickness direction. The horizontal sectional view which shows the inside of the compression mechanism of FIG. The expanded sectional view which shows arrangement | positioning of the magnet which is not divided | segmented by the side of the rotor of an electric motor as a comparative example. (A) is a front view, (b) is a side view, (c) is a cross-sectional view in the width direction, and (d) is a thickness of a magnet that is obliquely divided as another modification of the electric motor of the present invention. FIG. (A) is a front view, (b) is a side view, (c) is a cross-sectional view in the width direction, and (d). Is a sectional view in the thickness direction. (A) is a front view, (b) is a side view, (c) is a cross-sectional view in the width direction, and (d) is a thickness of a quadrant magnet that is still another modification of the electric motor of the present invention. Sectional drawing of a direction. FIG. 4 is a front view, FIG. 5B is a side view, and FIG. It is sectional drawing, (d) is sectional drawing of thickness direction. (A) is a front view, (b) is a side view, and (c) is a cross-sectional view in the width direction, with respect to a magnet having a groove near the axial center, which is still another modification of the electric motor of the present invention. d) is a sectional view in the thickness direction. (A) is a front view, (b) is a side view, and (c) is a cross-sectional view in the width direction, with respect to a magnet having a recess near the axial center, which is still another modification of the electric motor of the present invention. d) is a sectional view in the thickness direction. (A) is a front view, (b) is a side view, and (b) is a side view of a sectional view of a magnet in which the diffusion amount of heavy rare earths is partially increased near the axial center, which is still another modification of the electric motor of the present invention. c) is a cross-sectional view in the width direction, and (d) is a cross-sectional view in the thickness direction.

Next, an embodiment of an electric motor of the present invention will be described with reference to the drawings.
Embodiment
The hermetic compressor 1 shown in FIGS. 1 and 2 is used for compressing a refrigerant of an air conditioner, and includes a casing 2, an electric motor 3, a compression mechanism 4, an accumulator 5, and a shaft 6. I have. The electric motor 3, the compression mechanism 4 and the shaft 6 are accommodated in the casing 2.

  The sealed cylindrical casing 2 includes a cylindrical portion 10 and a pair of end plates 11 and 12 that close upper and lower opening ends of the cylindrical portion 10. The cylindrical portion 10 of the casing 2 houses a stator 8 and a rotor 9 of the electric motor 3 described later.

<Configuration of electric motor 3>
The electric motor 3 includes an annular stator 8 (stator), a rotor 9 (rotor) rotatably arranged in the internal space 8a of the stator 8, a plurality of coils 38, and a plurality of magnets 35 and 36. ing. The electric motor 3 is stored in the casing 2 in a state where the stator 8 is fixed to the inner wall of the casing 2.
The rotor 9 is connected to the shaft 6, can rotate with the shaft 6, and is disposed so as to be rotatable with respect to the stator 8.

  The stator 8 is fixed by welding a plurality of locations to the cylindrical portion 10 of the casing 2. The plurality of welded portions 7 are formed at equal intervals on the outer peripheral portion of the cylindrical portion 10.

  The plurality of coils 38 are wound and fixed around a plurality of (for example, nine) teeth 37 extending inwardly from the annular yoke portion 40 of the stator 8. When a plurality of coils 38 are energized, a magnetic field is generated.

  As shown in FIGS. 1 to 3, the magnets 35, 36 are respectively inserted and fixed in a plurality of (for example, six) slots 9 a extending in the axial direction of the rotor 9 along the direction of the shaft 6. It arrange | positions so that the magnetic field which generate | occur | produces from may be opposed.

  Also, as shown in FIGS. 4A to 4D, the magnets 35 and 36 are manufactured by diffusing heavy rare earth elements from the surface of the base material and entering the heavy rare earth elements between the grain boundaries of the base material. Has been.

  The base material of the magnets 35 and 36 is, for example, an iron-based material.

  The heavy rare earth element diffused inside the substrate is, for example, a material selected from at least one of dysprosium (Dy), terbium (Tb), and holmium (Ho).

  As shown in FIG. 3, heavy rare earth elements are opposed to the central portion CT where the distribution of the magnetic field generated from the coil 38 is strong, and are concentrated at the facing position I where the reverse magnetic field is most likely to be applied. That is, in the sectional views in the width direction and the thickness direction of the magnets 35 and 36 in FIGS. 3 and 4C to 4D, heavy rare earth elements are diffused from the surface of the base material of the magnets 35 and 36 to the inside. In the drawing, the amount of diffusion is large in the dark portion of the surface, and the amount of diffusion decreases as the color becomes thinner toward the center (the degree of diffusion in FIGS. (See the high diffusion region H, middle diffusion region M, and low diffusion region M shown in stages). Thereby, the high diffusion region H with a large diffusion amount can be arranged in the portion of the facing position I where the reverse magnetic field is most easily applied and is most likely to be demagnetized, and the coercive force can be improved.

  As shown in FIGS. 3 to 4, the magnets 35, 36 of the present embodiment are arranged in two vertically arranged in the axial direction of the shaft 6 so as to face the magnetic field generated from the coil 38. Thereby, the magnets 35 and 36 are arrange | positioned so that the high diffusion area | region H vicinity of the mutually opposing surface may be located in the opposing position I among those peripheral end surfaces. Thereby, the coercive force of the part of the opposing position I which is easy to demagnetize can be improved by arrangement | positioning of the some magnets 35 and 36. FIG.

  The stator 8 is spot welded at a plurality of welded portions 7 with a gap 13 secured between the stator 8 and the cylindrical portion 10 of the casing 2. Thereby, the vibration of the stator 8 is not easily transmitted to the casing 2.

<Configuration of compression mechanism 4>
As shown in FIGS. 1 and 5, the compression mechanism 4 includes a swinging piston 21 having a blade 22, a bush 23 that supports the blade 22 so as to swing, and a cylinder 27. The cylinder 27 has a cylinder chamber 24 that houses the oscillating piston 21, a bush hole 25 into which the bush 23 is rotatably inserted, and an oil supply communication hole 26 that communicates with the bush hole 25.

  The oscillating piston 21 receives the rotational driving force of the electric motor 3, and the eccentric portion 6 a of the shaft 6 rotates eccentrically, thereby oscillating inside the cylinder chamber 24, and thereby the refrigerant sucked from the suction pipe 28. Is compressed inside the cylinder chamber 24. The compressed refrigerant rises through the inside of the casing 2 and is discharged from the discharge pipe 29.

  The cylinder 27 has a lower block 27a and an upper block 27b. The cylinder 27 is screwed to the mounting plate 30. The mounting plate 30 is fixed to the cylindrical portion 10 of the casing 2 by a mounting plate joining portion 31. The mounting plate joint 31 is formed by spot welding.

<Features>
(1)
In the electric motor 3 of the embodiment, as shown in FIG. 3, the heavy rare earth elements are concentrated at the facing position I facing the central portion CT where the distribution of the magnetic field generated from the coil 38 is strong. Thereby, the high diffusion region H having a large amount of diffusion of the heavy rare earth element can be disposed in the portion of the facing position I where the reverse magnetic field is most easily applied and is most likely to be demagnetized. As a result, the coercive force of the magnets 35 and 36 can be improved.

(2)
Further, in the electric motor 3 of the embodiment, as shown in FIGS. 3 to 4, the magnets 35 and 36 of the present embodiment are two in the vertical direction in the axial direction of the shaft 6 so as to face the magnetic field generated from the coil 38. They are arranged side by side. Thereby, the magnets 35 and 36 are arrange | positioned so that the high diffusion area | region H with much diffusion amount of the heavy rare earth elements of the vicinity of the mutually opposing surface of those peripheral end surfaces may be located in the opposing position I. Thereby, the coercive force of the part of the opposing position I which is easy to demagnetize can be improved by arrangement | positioning of the some magnets 35 and 36. FIG.

  In addition, by dividing the magnets 35 and 36 into two, the dimensional accuracy is improved, and loss due to eddy current can be reduced.

(3)
Here, when a motor in which one magnet 135 in which a heavy rare earth element is diffused is inserted in the slot 9a of the rotor 9 shown in FIG. 6 as a comparative example, the heavy rare earth element is generated from the coil 38. At the facing position I facing the central portion CT where the magnetic field distribution is strong, the diffusion amount is low (that is, the high diffusion region H is small and the low diffusion region L is large). It is difficult to improve.

  On the other hand, in the electric motor 3 of the present embodiment, instead of using one grain boundary diffusion magnet, the high diffusion region H can be arranged at the opposed position I by dividing the grain boundary diffusion magnet into two sheets. An improvement in magnet holding force can be achieved.

  Note that “divided” as used in this specification is an expression used for convenience to facilitate understanding that two or more small magnets are arranged side by side. As described above, the two magnets 35 and 36 are individually subjected to grain boundary diffusion treatment of heavy rare earth elements, and a single magnet like the conventional product is subjected to grain boundary diffusion treatment. Needless to say, it was not manufactured after being processed.

  Thereby, by arranging the boundary surface in the axial direction of the electric motor 3 of the two magnets 35 and 36, a large number of grain boundary diffusion surfaces (that is, the high diffusion region H) are arranged at the opposed position I which is the central portion in the axial direction. It is possible to do.

  As a result, the grain boundary diffusion surface can be disposed in the axially central portion, so that the magnet coercive force at the axially central portion increases and the demagnetization resistance increases. Therefore, since the coercive force of the base material can be lowered, a material having a high magnetic flux density (Br) of the base material can be used, and the motor efficiency is improved. Further, since the magnet is divided, the loss due to the eddy current of the magnet is reduced.

(4)
Furthermore, in the electric motor 3 according to the embodiment, the at least two magnets 35 and 36 are arranged side by side in the rotation axis direction of the rotor 9, so that the rotation of the rotor 9 by the magnets 35 and 36 arranged in the rotor 9 is performed. It is possible to improve the coercivity of the portion at the facing position I that is most likely to be demagnetized in the axial direction.

(5)
In the hermetic compressor 1 of the embodiment, the electric motor 3 is housed in the casing 2 in a state where the stator 8 is fixed to the inner wall of the cylindrical casing 2 in which the stator 8 is sealed. Since the coercive force of the portion of the facing position I that is easily magnetized can be improved and the motor efficiency of the electric motor 3 can be improved, the efficiency of the compressor can be improved as a result.

<Modification>
(A)
As shown in FIG. 4, the magnets 35 and 36 of the above embodiment have the same rectangular parallelepiped shape, and their opposing surfaces 37 extend in parallel to the width direction of the magnet, but the present invention is not limited to this. It is not something.

  As a modification of the present invention, as shown in FIGS. 7 to 8, as the opposing surfaces of the magnets 35 and 36, an opposing surface 38 (see FIG. 7) that extends obliquely with respect to the width direction of the magnet, You may make it become the opposing surface 39 (refer FIG. 8) extended in step shape with respect to the width direction.

  In these cases, the length of the facing surfaces 38 and 39 is longer than that of the facing surface 37 (see FIG. 4) extending in parallel with the width direction of the magnet as in the above-described embodiment. Many can be placed. As a result, more high diffusion regions H can be disposed in the portion of the facing position I where the reverse magnetic field is most easily applied and is most likely to be demagnetized, and the coercive force can be further improved.

(B)
In the above embodiment, only two magnets 35 and 36 are arranged so as to face the magnetic field generated from the coil 38, but the present invention is not limited to this, and three or more magnets are arranged in the upper and lower directions. May be arranged side by side.

  That is, as shown in FIG. 9, as a modification of the present invention, four magnets 41, 42, 43, 44 each subjected to grain boundary diffusion treatment of heavy rare earth elements are arranged side by side, of which The two magnets 42 and 43 should just be arrange | positioned so that some high diffusion area | regions H may be located in the opposing position I among those peripheral end surfaces. Also in this case, the coercive force of the portion at the facing position I where demagnetization is likely can be improved by the arrangement of the plurality of magnets 41, 42, 43, 44.

  Further, since the four-divided magnets 41 to 44 are smaller in size than the two-divided magnets 35 and 36 of the above-described embodiment, it is possible to diffuse more heavy rare earth elements up to the vicinity of the central portion.

  In addition, the dimensional accuracy is further improved by the division of the magnets 41 to 44, and the loss due to the eddy current can be further reduced.

(C)
The magnets 35 and 36 of the above embodiment are arranged vertically so as to face the magnetic field generated from the coil 38, but the present invention is not limited to this, and the radial direction of the rotor 9 (that is, , May be arranged side by side in the magnet thickness direction).

  That is, as shown in FIG. 10, as a modification of the present invention, six magnets 51, 52, 53, 54, 55, and 56 that have been subjected to grain boundary diffusion treatment of heavy rare earth elements are arranged in the vertical direction. Near the center in the axial direction, two are arranged side by side in the thickness direction of the magnet. With such an arrangement, the four magnets 52, 53, 54, 55 near the center in the axial direction are arranged such that a part of the high diffusion region H of the peripheral end faces is located at the facing position I. Is possible. In this case, by arranging a large number of magnets 51 to 56 in the axial direction and the radial direction of the rotor 9, the peripheral end surfaces of the magnets 52, 53, 54, 55 having the high diffusion region H where the diffusion amount of heavy rare earth elements is large are formed. It is possible to dispose more at the facing position I, thereby further improving the coercivity of the portion at the facing position I where demagnetization is likely to occur.

  Moreover, since the magnets 51 to 56 divided into six are smaller in size than the two-divided magnets 35 and 36 of the above-described embodiment, it is possible to diffuse more heavy rare earth elements closer to the center. is there. In particular, the four magnets 52, 53, 54, 55 near the axial center are half the thickness of the other magnets 51, 56. It is possible to diffuse deeply (see the high diffusion region H in FIG. 10).

  Moreover, the dimensional accuracy is further improved by dividing the magnets 51 to 56 into six, and the loss due to the eddy current can be further reduced.

(D)
Furthermore, although the magnets 35 and 36 of the above embodiment are divided into two upper and lower parts so as to face the magnetic field generated from the coil 38, the present invention is not limited to this and is a single magnet. However, the heavy rare earth elements need only be concentrated at the facing position I facing the central portion CT where the distribution of the magnetic field generated from the coil 38 is strong.

  That is, as still another modification of the present invention, as shown in FIG. 11, one magnet 61 has a groove 62 extending in parallel with the width direction of the magnet as a recess on the surface facing the coil 38. The groove 62 is arranged in the vicinity of the center of the magnet 61 in the axial direction so as to be located at the facing position I.

  The uneven surface of the groove 62 near the axial center of the magnet 61 allows the surface area of the magnet 61 to be partially enlarged, thereby increasing the amount of heavy rare earth element diffusion around the groove 62 ( (See the high diffusion region H in the vicinity of the facing position I in FIGS. 11C and 11D). As a result, the coercive force of the portion at the facing position I that is likely to be demagnetized can be improved.

(E)
Further, as another modification of the present invention using a form in which the surface of one magnet is uneven, as shown in FIG. 12, one magnet 71 has a concave portion on the surface facing the coil 38. Two circular recesses 72 are arranged in parallel with the width direction, and the circular recesses 72 are arranged in the vicinity of the center of the magnet 61 in the axial direction so as to be located at the facing position I.

  Also in this case, the surface area of the magnet 61 can be partially enlarged by the uneven surface of the circular recess 72 near the axial center of the magnet 61, and the amount of heavy rare earth element diffusion around the groove 62 can be increased. (See the high diffusion region H near the facing position I in FIGS. 12C and 12D). As a result, the coercive force of the portion at the facing position I that is likely to be demagnetized can be improved.

  11 to 12 is only an example of a configuration in which the surface of one magnet is provided with irregularities, and the concave portion and / or the convex portion are positioned at the facing position I even in other configurations. (For example, a form in which small irregularities are continuously applied), the surface area of the magnet can be partially enlarged, and the diffusion amount of heavy rare earth elements can be partially increased around the opposing position I. It becomes possible to increase.

(F)
Furthermore, as yet another modification of the present invention, one magnet 81 is provided in the step of grain boundary diffusion treatment of heavy rare earth elements as shown in FIG. 13 without providing irregularities on the surface of one magnet. Heavy rare earth elements may be concentrated and diffused in the region 82 in the vicinity of the opposing position I in the axial direction.

  Also in this case, it is possible to increase the diffusion amount of heavy rare earth elements around the region 82 (see the high diffusion region H near the facing position I in FIGS. 13C and 13D). As a result, it is possible to improve the coercive force of the portion at the facing position I that is likely to be demagnetized.

  As a method of concentrating and diffusing the heavy rare earth element in the region 82, various methods such as diffusing the heavy rare earth element with the masking around the region 82 can be employed.

  The present invention can be variously applied to an electric motor in which a magnet is installed on a rotor and a hermetic compressor including the electric motor.

DESCRIPTION OF SYMBOLS 1 Hermetic compressor 2 Casing 3 Electric motor 6 Shaft 8 Stator 9 Rotor 35, 36 Magnet 38 Coil 41-44 Magnet 51-56 Magnet 61, 71, 81 Magnet 62 Groove 72 Circular recessed part

JP 2003-70214 A JP 2002-262490 A

Claims (6)

A stator (8) fixed to an attachment target;
A rotor (9) arranged rotatably with respect to the stator (8);
A coil (38) fixed to the stator (8) and generating a magnetic field;
Magnets (35, 36, 41-44, 51-56, 61, 71, 81) fixed to the rotor (9) and arranged to face the magnetic field generated from the coil (38);
In an electric motor with
The magnet is manufactured by diffusing heavy rare earth elements from the surface of the substrate,
The heavy rare earth element is concentrated at a facing position facing a portion where the distribution of the magnetic field generated from the coil (38) is strong.
Electric motor (3). A plurality of the magnets (35, 36, 41-44, 51-56) are arranged to face the magnetic field generated from the coil (38),
At least two of the plurality of magnets are arranged such that a part of their peripheral end faces is located at the facing position.
The electric motor (3) according to claim 1. At least two of the magnets (35, 36, 41 to 44, 51 to 56) are arranged side by side in the rotation axis direction of the rotor (9).
The electric motor (3) according to claim 2. At least two of the magnets (51 to 56) are arranged side by side in the radial direction of the rotor (9),
The electric motor (3) according to claim 2 or 3. The magnet (61, 71) has a concave portion and / or a convex portion (62, 72) on a surface facing the coil (38),
The concave portion and / or the convex portion (62, 72) is disposed so as to be located at the facing position.
The electric motor (3) according to claim 1 or 2. A sealed cylindrical casing (2);
An electric motor (3) according to any one of claims 1 to 5,
The electric motor (3) is stored in the casing (2) in a state where the stator (8) is fixed to the inner wall of the casing (2).
Compressor (1).

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