JP2012105410A - Electric motor and compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor in which a magnetic flux distribution of a rotor surface is made a sine wave, a torque vibration causing vibration is restricted and mechanical strength against centrifugal force and electromagnetic vibration force is improved compared to conventional punching slits.SOLUTION: The electric motor of the present invention comprises a stator and a permanent magnet buried rotor. The rotor comprises a rotor core having multiple magnet insertion holes formed along its outer peripheral edge and multiple permanent magnets inserted into the magnet insertion holes. The rotor core is formed at an outer peripheral core outside the magnet insertion holes and between electrodes by laminating a predetermined number of electromagnetic steel sheets having a magnetic flux control section configured of thinned sheets formed.

Description

  The present invention relates to an electric motor. Specifically, it relates to the structure of the rotor. Moreover, it is related with the compressor carrying the electric motor.

  Recent permanent magnet embedded motors are strongly required to be small and highly efficient, and in addition, there is a problem of reducing vibration and noise. In addition, due to the recent increase in environmental awareness, it is effective to reduce torque pulsation in order to reduce vibration and noise in motors installed in air conditioner compressors, electric vehicles, hybrid vehicles, and fuel cell vehicles. It is.

  Conventionally, a slit hole is provided in the outer periphery of the magnet housing hole of the rotor to reduce the armature reaction magnetic flux, and improve the magnetic flux distribution of the outer peripheral core, thereby reducing the noise and vibration. An electric motor has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 4248984

  However, in order to effectively use the effect of the slit hole, the one described in Patent Document 1 requires that the punched portion be disposed near the rotor surface, and the magnetic path of the iron core is narrow on the outer periphery of the rotor. There exists a subject that the thin part exists and the strength against centrifugal force during rotation is reduced.

  Further, since the iron core on the magnetic pole surface (the outer peripheral portion of the magnet housing hole) has a small area, the degree of freedom in designing the width, shape, etc. by punching is low. Moreover, it can be said that there are large restrictions on the processing accuracy of the punching press, and there are great restrictions on the improvement of the magnetic flux distribution.

  The present invention has been made to solve the above-described problems. By providing a magnetic flux control unit configured with a thin plate thickness on the magnetic pole surface, the magnetic flux distribution on the rotor surface is converted into a sine wave, and vibration is generated. An electric motor that suppresses the torque pulsation that causes the above-described problem and has improved mechanical strength against centrifugal force and electromagnetic excitation force as compared with a conventional punching slit, and a compressor that uses the electric motor.

An electric motor according to the present invention is an electric motor including a stator and a permanent magnet embedded rotor,
The rotor is
A rotor core in which a plurality of magnet insertion holes are formed along the outer periphery;
A plurality of permanent magnets inserted into the magnet insertion holes,
The rotor core is formed by laminating a predetermined number of magnetic steel sheets each having a magnetic flux control unit formed by reducing the plate thickness at the outer peripheral core part outside the magnet insertion hole and between the poles. It is characterized by.

  In the electric motor according to the present invention, the rotor core has a predetermined number of electromagnetic steel plates in which a magnetic flux control unit configured by thinning the plate thickness is formed on the outer peripheral core part outside the magnet insertion hole and the inter-pole part. By forming the laminated structure, the magnetic flux distribution on the rotor surface is made sinusoidal, and the torque pulsation that causes vibration is suppressed, and mechanical force against centrifugal force and electromagnetic excitation force is compared to conventional punch slits. There is an effect of improving the strength.

It is a figure shown for a comparison and is a cross-sectional view of a general electric motor 600. The figure shown for a comparison and the cross-sectional view of the stator 610 of the general electric motor 600. FIG. It is a figure shown for a comparison and is a cross-sectional view of a stator core 611 of a general electric motor 600. The figure shown for a comparison and the cross-sectional view of the rotor 620 of the common electric motor 600. FIG. It is a figure shown for a comparison and is a cross-sectional view of the rotor core 621 of a general electric motor 600. The figure shown for a comparison and the fragmentary cross-sectional view of the common rotor 720 which has the slit 725. FIG. The enlarged view of FIG. It is a figure shown for a comparison and is a partial cross-sectional view of a general rotor core 721. FIG. 3 shows the first embodiment and is a cross-sectional view of the electric motor 100. FIG. 3 shows the first embodiment, and is a cross-sectional view of the rotor 20 of the electric motor 100. FIG. 3 shows the first embodiment, and is a cross-sectional view of a rotor core 21 of the electric motor 100. FIG. The elements on larger scale of FIG. The elements on larger scale of FIG. AA sectional drawing of FIG. The elements on larger scale of FIG. BB sectional drawing of FIG. FIG. 6 shows the first embodiment, and shows the waveform of the induced voltage induced in the winding of the stator 10 when the rotor 20 has no magnetic flux control unit. FIG. 6 shows the first embodiment, and shows a waveform of an induced voltage induced in the winding of the stator 10 when the rotor 20 has a magnetic flux control unit. FIG. 6 shows the first embodiment, and compares the harmonic content of induced voltage induced in the winding of the stator 10 with and without the magnetic flux control unit. FIG. 5 shows the first embodiment, and shows the analysis result of deformation with respect to centrifugal force when the magnetic flux control unit of the rotor 20 is punched out. FIG. 5 shows the first embodiment, and shows the analysis result of deformation with respect to centrifugal force when the plate thickness of the magnetic flux control unit of the rotor 20 is reduced. FIG. 5 shows the first embodiment, and shows the analysis result of stress when the magnetic flux control unit of the rotor 20 is punched and when the plate thickness of the magnetic flux control unit is reduced. FIG. 5 shows the first embodiment, and is a partial cross-sectional view of a rotor 120 of a first modification. The enlarged view of FIG. FIG. 6 shows the first embodiment, and is a partial cross-sectional view of a rotor 220 of a second modification. The enlarged view of FIG. CC sectional drawing of FIG. The elements on larger scale of FIG. DD sectional drawing of FIG. FIG. 5 shows the first embodiment, and is a partial cross-sectional view of a rotor 320 of a third modification. The enlarged view of FIG. The E section enlarged view of FIG. FF sectional drawing of FIG. FIG. 5 shows the second embodiment and is a transverse cross-sectional view of a rotor 420; FIG. 5 shows the second embodiment and is a cross-sectional view of a rotor core 421. The elements on larger scale of FIG. GG sectional drawing of FIG. FIG. 5 shows the second embodiment, and shows a waveform of an induced voltage induced in a stator winding when the rotor 420 has a magnetic flux control unit. FIG. 6 shows the second embodiment, and compares the harmonic content of induced voltage induced in the winding of the stator with and without the magnetic flux control unit. FIG. 5 shows the third embodiment and is a longitudinal sectional view of a rotary compressor 500.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of a general electric motor 600 shown for comparison. A general electric motor 600 shown in FIG. 1 is, for example, a brushless DC motor. The electric motor 600 includes a stator 610 and a rotor 620 disposed inside the stator 610 via a gap 640.

  FIG. 2 is a view for comparison, and is a cross-sectional view of a stator 610 of a general electric motor 600. The stator 610 includes at least a stator core 611 and a winding 612 (insulated from a stator core 611 by an insulating member not shown). The windings 612 are concentrated windings wound around the teeth 613, but may be distributed windings. The winding 612 is a three-phase winding, and the connection method is Y connection (star connection, star connection). However, the connection method may be a triangular connection.

  FIG. 3 is a view for comparison, and is a cross-sectional view of a stator core 611 of a general electric motor 600. The stator core 611 is substantially ring-shaped, and a ring-shaped core back 615 is formed on the outer peripheral side. Nine teeth 613 are radially formed from the core back 615 to the rotor 620 side. Nine teeth 613 are arranged at substantially equal intervals in the circumferential direction. The circumferential width of the teeth 613 is substantially constant in the radial direction.

  A space between adjacent teeth 613 is called a slot 614. The number of slots 614 is nine, which is the same as the number of teeth 613. Since the circumferential width of the teeth 613 is substantially constant in the radial direction, the circumferential width of the slot 614 is configured to gradually increase from the inside toward the outside (core back 615 side). The slot 614 opens to the rotor 620 side at the slot opening 614a.

  The stator core 611 is formed by laminating a predetermined number of thin electromagnetic steel sheets having a thickness of 0.7 mm or less in a predetermined shape.

  FIG. 4 is a view for comparison, and is a cross-sectional view of a rotor 620 of a general electric motor 600. The rotor 620 is a permanent magnet embedded type, and includes at least a rotor iron core 621 and a plate-shaped permanent magnet 622 inserted into the magnet insertion hole 623 of the rotor iron core 621.

  The six permanent magnets 622 are inserted into magnet insertion holes 623 formed along the outer peripheral edge of the rotor core 621 to constitute a six-pole rotor 620.

  The permanent magnet 622 of the rotor 620 is mounted with a neodymium rare earth magnet mainly composed of Nd—Fe—B (neodymium, iron, boron) and has a flat plate shape with a thickness of about 2 mm.

  FIG. 5 is a view for comparison, and is a cross-sectional view of a rotor core 621 of a general electric motor 600. The rotor iron core 621 has a substantially cylindrical shape, and six magnet insertion holes 623 having a substantially rectangular cross-sectional shape are formed along the outer peripheral edge. In the cross section, the six magnet insertion holes 623 form a substantially hexagonal shape. A shaft hole 624 into which a rotation shaft (not shown) is inserted is provided at a substantially central portion of the rotor core 621.

  Similarly to the stator core 611, the rotor core 621 is formed by forming a thin electromagnetic steel sheet having a thickness of 0.7 mm or less into a predetermined shape and laminating a predetermined number of sheets.

  In the rotor 620 of the general electric motor 600 configured as described above, the magnetic flux density on the surface of the rotor 620 is less likely to have a waveform close to a sine wave due to the influence of the outer peripheral core part outside the magnet insertion hole 623. In addition, there is a problem that a magnetic flux (an armature reaction magnetic flux) generated by a current flowing through the winding 612 of the stator 610 wraps around the outer peripheral core portion outside the magnet insertion hole 623.

  As a countermeasure, it is common to provide a slit in the outer peripheral core part outside the magnet insertion hole. 6 to 8 are views for comparison, FIG. 6 is a partial cross-sectional view of a general rotor 720 having a slit 725, FIG. 7 is an enlarged view of FIG. 6, and FIG. 8 is a general rotor. 3 is a partial cross-sectional view of an iron core 721. FIG. For example, as shown in FIG. 6, a plurality of slits 725 are formed in a rotor core 721 of another general rotor 720 in the outer peripheral core portion outside the magnet insertion hole 723 into which the permanent magnet 722 is inserted. Has been.

  Specifically, as shown in FIG. 7, in one magnetic pole, slits 725 a to 725 d having substantially elongated holes are formed in the outer peripheral core portion outside the magnet insertion hole 723. The slit 725a is positioned on the magnetic pole center line, and slits 725b to 725d are sequentially formed between the left and right poles with the slit 725a as the center. The slits 725 b to 725 d are oriented so that the outward extension line intersects the magnetic pole center line outside the rotor 720. Since the magnetic flux of the permanent magnet 722 is controlled as described above by the slits 725a to 725d, the magnetic flux density on the surface of the rotor 720 has a waveform close to a sine wave.

  However, the oblong hole-shaped slits 725a to 725d provided in the general rotor 720 are formed by punching electromagnetic steel sheets (0.7 mm or less) into a predetermined shape and laminating a predetermined number of rotor cores 721. At the same time, it is formed by punching.

  In order to effectively use the effects of the slits 725a to 725d, it is necessary to arrange the slits 725a to 725d as punched portions near the surface of the rotor 720, and the magnetic path of the iron core is narrow on the outer periphery of the rotor. There exists a part (Ta-Td, T, refer FIG. 8), and the subject with respect to the strength with respect to the centrifugal force at the time of rotation falls. The minimum dimension of the thin part (Ta to Td, T) is about the thickness (0.7 mm or less) of the electromagnetic steel sheet.

  The present embodiment solves the above-described problem (insufficient strength) of a general rotor 720 having slits 725a to 725d formed by punched portions.

  In the present embodiment, unlike a general rotor 720, a portion corresponding to the slits 725a to 725d is not a completely punched slit 725a to 725d, but a magnetic flux control unit configured by reducing the plate thickness. The present invention provides an excellent rotor that has a function of controlling the magnetic flux of a permanent magnet and that does not decrease the strength against centrifugal force during rotation. In the present embodiment, a magnetic flux control unit having a thin plate thickness is also formed on the outer periphery of the magnet insertion hole in the inter-polar part.

  9 to 16 are diagrams showing the first embodiment. FIG. 9 is a transverse sectional view of the electric motor 100, FIG. 10 is a transverse sectional view of the rotor 20 of the electric motor 100, and FIG. 11 is an illustration of the rotor core 21 of the electric motor 100. 12 is a partially enlarged view of FIG. 10, FIG. 13 is a partially enlarged view of FIG. 11, FIG. 14 is a sectional view taken along line AA of FIG. 12, FIG. 15 is a partially enlarged view of FIG. It is BB sectional drawing of 15.

  The configuration of the electric motor 100 will be described with reference to FIGS. 9 to 16. The electric motor 100 shown in FIG. 9 is also a brushless DC motor, for example. The electric motor 100 includes a stator 10 and a rotor 20 disposed inside the stator 10 via a gap 40.

  Since the configuration of the stator 10 is the same as that of the stator 610 of a general electric motor 600, the description thereof is omitted.

  As shown in FIG. 10, the rotor 20 is a permanent magnet embedded type, and includes at least a rotor core 21 and a plate-shaped permanent magnet 22 inserted into a magnet insertion hole 23 of the rotor core 21. This embodiment is characterized by the configuration of the rotor core 21.

  The six permanent magnets 22 are made into magnet insertion holes 23 formed along the outer peripheral edge of the rotor core 21 to constitute a six-pole rotor 20.

  The permanent magnet 22 of the rotor 20 is mounted with a neodymium rare earth magnet mainly composed of Nd—Fe—B (neodymium, iron, boron) and has a flat plate shape with a thickness of about 2 mm.

  As shown in FIG. 11, the rotor core 21 has a substantially columnar shape, and six magnet insertion holes 23 having a substantially rectangular cross section are formed along the outer peripheral edge. In the cross section, the six magnet insertion holes 23 form a substantially hexagonal shape. A shaft hole 24 into which a rotating shaft (not shown) is inserted is provided at a substantially central portion of the rotor core 21.

  The rotor core 21 is formed by laminating a predetermined number of thin electromagnetic steel sheets having a thickness of 0.7 mm or less in a predetermined shape.

  The rotor core 21 controls the magnetic flux of the permanent magnet 22 on the outer peripheral core portion and the interpole portion outside each magnet insertion hole 23 (so that the magnetic flux density on the surface of the rotor 20 is a sine wave). 30 is formed. The magnetic flux control unit 30 is provided for each electromagnetic steel sheet constituting the rotor core 21.

  As shown in FIG. 12, the magnetic flux control unit 30 is formed on the outer peripheral iron core portion of each magnet insertion hole 23, and includes a plurality of magnetic flux control units 30 a to 30 d having a long hole shape in plan view, and the magnet insertion holes 23. It is connected to the end portion, is formed at the inter-pole portion, and is constituted by a polygonal magnetic flux control unit 30e in plan view.

  The magnetic flux control unit 30a is located on the magnetic pole center line, and the magnetic flux control units 30b to 30d are sequentially formed between the left and right poles with the magnetic flux control unit 30a as the center. The magnetic flux control units 30 b to 30 d are oriented in a direction in which the outward extension line intersects the magnetic pole center line outside the rotor 20. Since the magnetic flux of the permanent magnet 22 is controlled as described above by the magnetic flux control units 30a to 30d, the magnetic flux density on the surface of the rotor 20 has a waveform close to a sine wave. In addition, the circumferential direction width | variety of the magnetic flux control parts 30a-30d is about 2 mm, for example.

  The inter-pole magnetic flux control unit 30e suppresses leakage of magnetic flux of the permanent magnet 22 between the poles.

  As shown in FIG. 13, the minimum dimensions Ta1, Tb1, Tc1, Td1, and Te1 of the magnetic flux control units 30a to 30e and the outer peripheral portion of the rotor core 21 are about the thickness (0.7 mm or less) of the electromagnetic steel sheet. It is.

  Further, the minimum dimensions Ta2, Tb2, Tc2, and Td2 between the magnetic flux control units 30a to 30d and the magnet insertion hole 23 are also about the plate thickness (0.7 mm or less) of the electromagnetic steel plate.

  As shown in FIGS. 14 and 16, the thickness W0 of the electromagnetic steel plate 21a constituting the rotor core 21 is, for example, 0.35 mm, and the thickness W1 of the magnetic flux control units 30a to 30e is, for example, 0. .1mm. Each magnetic steel sheet 21a includes magnetic flux control units 30a to 30e, and the rotor core 21 of the present embodiment fixes the phase of the electromagnetic steel sheets 21a by caulking and is laminated in the axial direction.

  In the present embodiment, the magnetic flux control units 30a to 30e are formed by thinning the thickness of the electromagnetic steel plate 21a by etching. In addition, the same effect can be obtained even if the thickness of the electromagnetic steel sheet 21a is reduced by pressing or the like.

  Next, the etching process which is a basic process for forming the magnetic flux control units 30a to 30e will be described.

  A pretreatment is applied to the electrical steel sheet, and a resist is applied. Using this mask, the magnetic flux control units 30a to 30e are exposed to light and developed. The resist is removed based on this shape and processed with an etching solution.

  If the remaining resist is removed after the processing with the etching solution, the electrical steel sheet 21a having the desired magnetic flux control units 30a to 30e can be formed. For such production, for example, photo-etching is effective, and it is also effective to use a method of precisely processing fine holes using a metal mask.

  If etching is used, the magnetic flux controllers 30a to 30e can be formed with extremely high processing accuracy, for example, with an error of ± 10 μm or less, preferably ± 5 μm or less.

  In the present embodiment, seven long hole-shaped magnetic flux control units 30a to 30d (one magnetic flux control unit 30a and two magnetic flux control units 30b) are provided on the outer peripheral iron core portion of the permanent magnet 22 of each magnetic pole. ˜30d), the magnetic flux control unit 30a is arranged at the magnetic pole center, and the magnetic flux control units 30b to 30d are arranged symmetrically in order on the left and right of the magnetic flux control unit 30a. Further, the seven long hole-shaped magnetic flux control units 30a to 30d are formed so as to face the central part of the magnetic pole. With this configuration, the magnetic flux of the permanent magnet 22 is concentrated at the magnetic pole center, and the magnetic flux density distribution is adjusted from the magnetic pole center so as to have a sine wave shape.

  Since the magnetic flux control units 30a to 30d processed to have a thickness W1 of, for example, 0.1 mm have a narrow magnetic path, the magnetic permeability is low and the magnetic flux does not easily flow. By appropriately arranging the magnetic flux control units 30a to 30d, the flow of magnetic flux can be controlled, and the magnetic flux density distribution on the surface of the rotor 20 can be made sinusoidal.

  17 to 19 are diagrams showing the first embodiment, and FIG. 17 is a diagram showing a waveform of an induced voltage induced in the winding of the stator 10 when the rotor 20 does not have a magnetic flux control unit. FIG. 19 is a diagram showing a waveform of an induced voltage induced in the winding of the stator 10 when the magnetic flux control unit of the rotor 20 is provided, and FIG. 19 is a harmonic component of the induced voltage induced in the winding of the stator 10. It is the figure which compared the content rate with a magnetic flux control part and with a magnetic flux control part.

  When the rotor 20 does not have the magnetic flux controllers 30a to 30d, the waveform of the induced voltage induced in the winding of the stator 10 is a waveform as shown in FIG. Further, when the rotor 20 has the magnetic flux control units 30a to 30d, the waveform of the induced voltage induced in the winding of the stator 10 is a waveform as shown in FIG. The frequency analysis of these waveforms was performed, and the harmonic content of the induced voltage (value obtained by dividing the square root of the square sum of the amplitudes of the harmonic components by the amplitude of the fundamental component) was compared, as shown in FIG. The result was halved to 7.6% without the magnetic flux control unit and 3.6% with the magnetic flux control unit.

  The torque for driving the rotor 20 is proportional to the product of the induced voltage of the winding of the stator 10 and the current flowing through the winding. Therefore, by providing the rotor 20 with the magnetic flux control units 30a to 30d, The harmonic component can be reduced, and the motor 100 with low vibration and high efficiency can be obtained.

  Further, the magnetic flux control unit 30e formed by reducing the thickness of the inter-electrode portion of the electromagnetic steel sheet makes the magnetic flux that is short-circuited between adjacent magnetic poles having different polarities difficult to flow by increasing the magnetic resistance. It has the function of controlling to flow to the 10 side. By reducing the short-circuit magnetic flux that is short-circuited between the magnetic poles and interlinking the magnetic flux of the permanent magnet 22 with the stator 10, the magnet torque generated by the stator 10 is improved, and the highly efficient electric motor 100 that can be driven at a low current is obtained. can get.

  The magnetic flux control as described above was possible by punching out the magnetic flux control unit, but in that case, in order to effectively use the effect of the magnetic flux control unit, it is necessary to arrange the punched part near the rotor surface. In addition, there is a thin-walled portion where the magnetic path of the iron core is narrow on the outer periphery of the rotor, and the reduction in strength against centrifugal force during rotation has been a problem.

  20 to 22 are diagrams showing the first embodiment. FIG. 20 is a diagram showing an analysis result of deformation with respect to centrifugal force when the magnetic flux control unit of the rotor 20 is punched. FIG. 21 is a magnetic flux control of the rotor 20. FIG. 22 is a diagram showing the analysis result of deformation with respect to centrifugal force when the plate thickness of the magnetic part is reduced. FIG. 22 shows the analysis result of stress when the magnetic flux control unit of the rotor 20 is punched and when the magnetic flux control unit is made thin. FIG.

  20 and 21 are deformations (enlarged 2000 times) against centrifugal force when the rotor 20 is rotated at 100 rpm (rotation per minute), and FIG. 20 shows the magnetic flux of the rotor 20. FIG. 21 shows a modification when the thickness of the magnetic flux control part of the rotor 20 is reduced.

  20 is compared with FIG. 21, after punching out the magnetic flux control units 30a to 30e, the plate thickness is reduced (for example, the thickness is reduced to 0.1 mm for an electromagnetic steel plate having a thickness of 0.35 mm). ), It can be seen that the strength near the outer periphery of the rotor 20 is greatly improved, and the deformation of each magnetic pole portion due to the centrifugal force acting on the permanent magnet 22 is remarkably reduced.

  Further, as shown in FIG. 22, the Mises stress of the outer peripheral core part outside the magnetic flux controller when the rotational speed is changed (simply speaking, the concept of Mises stress is such that a complex load is applied from multiple directions. In the stress field, the value projected on the uniaxial tensile or compressive stress is obtained by punching out the magnetic flux control units 30a to 30e and then reducing the plate thickness (for example, for a magnetic steel sheet having a thickness of 0.35 mm). By reducing the thickness of the plate to 0.1 mm, it can be reduced to about 1/3 or less.

  In the present embodiment, the highly efficient electric motor 100 with low vibration is obtained, and the highly reliable electric motor 100 with improved mechanical strength against centrifugal force is obtained.

  23 and 24 are diagrams showing the first embodiment. FIG. 23 is a partial cross-sectional view of the rotor 120 of the first modification, and FIG. 24 is an enlarged view of FIG. As shown in FIG. 23, the rotor 120 according to the first modification controls the magnetic flux of the permanent magnet 122 to the outer peripheral core portion and the inter-pole portion outside each magnet insertion hole 123 of the rotor core 121 (rotor 120). The magnetic flux control unit 130 is formed to suppress leakage of the permanent magnet 122 between the poles so that the surface magnetic flux density becomes a sine wave. The magnetic flux control unit 130 is provided for each electromagnetic steel sheet constituting the rotor core 121.

  As shown in FIG. 24, the magnetic flux control unit 130 is formed on the outer peripheral iron core portion outside each magnet insertion hole 123, and includes a plurality of magnetic flux control units 130 a to 130 d having a long hole shape in plan view, and the magnet insertion hole 123. It is connected to the end portion, is formed at the inter-pole portion, and is constituted by a polygonal magnetic flux control unit 130e in plan view.

  The magnetic flux controllers 130a to 130e are different from the magnetic flux controllers 30a to 30e shown in FIG. 12 in that the magnetic flux controllers 130a to 130d are in contact with the outer periphery of the rotor 120 and the magnet insertion hole 123, and the magnetic flux control. That is, the portion 130 e is in contact with the outer periphery of the rotor 120.

  The magnetic flux control unit 130a is located on the magnetic pole center line, and magnetic flux control units 130b to 130d are sequentially formed between the left and right poles with the magnetic flux control unit 130a as the center. The magnetic flux control units 130 b to 130 d are oriented in a direction in which the outward extension line intersects the magnetic pole center line outside the rotor 20. Since the magnetic flux of the permanent magnet 122 is controlled as described above by the magnetic flux control units 130a to 130d, the magnetic flux density on the surface of the rotor 120 has a waveform close to a sine wave. In addition, the circumferential direction width | variety of the magnetic flux control parts 130a-130d is about 2 mm, for example.

  The inter-pole magnetic flux control unit 130e suppresses leakage of magnetic flux of the permanent magnet 122 between the poles.

  Compared with the rotor 20 shown in FIG. 12, the mechanical strength of the rotor 120 of Modification 1 is slightly reduced, but the magnetic flux control units 130 a to 130 d are in contact with the magnet insertion hole 123 and the outer peripheral portion of the rotor 120. Therefore, the controllability of the magnetic flux flow of the permanent magnet 122 is improved, and the magnetic flux density distribution on the surface of the rotor 120 can be optimized in a sine wave shape. Moreover, the magnetic flux control part 130e on the outer periphery of the magnet insertion hole 123 in the inter-polar part is also in contact with the outer peripheral part of the rotor 120, so that a leakage magnetic flux between the poles is reduced and a highly efficient electric motor with improved magnet torque is configured. It becomes possible.

  When the rotor core 121 is punched, it is necessary to arrange an iron core portion on the surface of the rotor 120 due to the configuration, and there is a problem that magnetic flux is easily short-circuited at the iron core portion of the rotor 120 surface. In the rotor 120 of the first modification, the controllability of the magnetic flux of the permanent magnet 122 can be improved.

  In addition, the fact that the thin part of the magnetic flux control unit 130 is in contact with the outer periphery of the rotor 120 has the following effects. In general, an eddy current flows in an iron core in the direction to cancel the fluctuation of magnetic flux with respect to an externally varying magnetic field, and eddy current loss is generated by this eddy current. For this reason, the iron core of an electric motor is comprised by laminating | stacking a thin electromagnetic steel plate with a small cross-sectional area so that a specific resistance may become high. Further, eddy current loss of the rotor core is likely to occur on the rotor surface where the magnetic fluctuation is large. In the configuration of FIG. 23, since the magnetic flux controller 130 locally reduces the plate thickness of the surface of the rotor core 121, the specific resistance of the surface of the rotor core 121 is increased, and the eddy current is less likely to flow. Eddy current loss can be reduced.

  FIGS. 25 to 29 are diagrams showing the first embodiment. FIG. 25 is a partial cross-sectional view of a rotor 220 according to a second modification, FIG. 26 is an enlarged view of FIG. 25, and FIG. 28 is a partially enlarged view of FIG. 26, and FIG. 29 is a sectional view taken along the line DD of FIG.

  The long hole-shaped magnetic flux control unit 230 of the rotor 220 of Modification 2 is characterized in that it is composed of a plurality of magnetic flux control units having different plate thicknesses.

  As illustrated in FIG. 25, the rotor 220 according to the second modification controls the magnetic flux of the permanent magnet 222 to the outer peripheral core portion and the interpole portion outside the magnet insertion holes 223 of the rotor core 221 (rotor 220. A magnetic flux controller 230 is formed to suppress leakage of the permanent magnet 222 between the poles so that the magnetic flux density on the surface becomes a sine wave. The magnetic flux control unit 230 is provided for each electromagnetic steel plate constituting the rotor core 221.

  As shown in FIG. 26, the magnetic flux control unit 230 is formed on the outer peripheral iron core of each magnet insertion hole 223, and has a plurality of long hole-shaped magnetic flux control units 230 a to 230 d and a magnet insertion hole 223 in plan view. It is connected to the end portion, is formed at the inter-pole portion, and is composed of a polygonal magnetic flux control unit 230e in plan view.

  The magnetic flux control units 230a to 230e are different from the magnetic flux control units 30a to 30e shown in FIG. 12 in that the thicknesses of the magnetic flux control units 230a to 230d are different. The point is that it is thinner.

  As shown in FIG. 27, the thickness of the magnetic flux control unit 230a located on the magnetic pole center line is the maximum, and the thickness gradually decreases in the order of the magnetic flux control units 230b to 230d. The magnetic flux control unit 230d has a thickness of zero, that is, a slit.

  The magnetic flux control unit 230a is located on the magnetic pole center line, and the magnetic flux control units 230b to 230d are sequentially formed between the left and right poles with the magnetic flux control unit 230a as the center. The magnetic flux control units 230 b to 230 d are oriented in a direction in which the outward extension line intersects the magnetic pole center line outside the rotor 220. Since the magnetic flux of the permanent magnet 222 is controlled as described above by the magnetic flux control units 230a to 230d, the magnetic flux density on the surface of the rotor 220 has a waveform close to a sine wave. In addition, the circumferential direction width | variety of the magnetic flux control parts 230a-230d is about 2 mm, for example.

  The inter-pole magnetic flux control unit 230e suppresses leakage of magnetic flux of the permanent magnet 222 between the poles. As shown in FIG. 9, here, the thickness of the magnetic flux controller 230e is the same as the thickness of the magnetic flux controller 230a.

  In the rotor 20 and the rotor 120 of the first modification, the optimum shape of the magnetic path was examined using the long hole-shaped magnetic flux control units 30 and 130 for magnetic flux control as parameters of the orientation, width, length, and the like. In the rotor 220 of the modified example 2, the magnetic path design likelihood is improved by adding the magnetic path design based on the thickness of the magnetic flux controller 230, and the magnetic flux density distribution on the surface of the rotor 220 is made sinusoidal. It becomes possible to optimize.

  30 to 33 are diagrams showing the first embodiment. FIG. 30 is a partial cross-sectional view of a rotor 320 according to a third modification, FIG. 31 is an enlarged view of FIG. 30, and FIG. 33 is a cross-sectional view taken along line FF in FIG.

  The long hole-shaped magnetic flux control unit 330 of the rotor 320 of Modification 3 is characterized in that each of the magnetic flux control units 330 is composed of a zero-thickness region and a thin portion.

  As illustrated in FIG. 30, the rotor 320 of the third modification controls the magnetic flux of the permanent magnet 322 at the outer peripheral core portion and the inter-pole portion outside each magnet insertion hole 323 of the rotor core 321 (rotor 320). A magnetic flux control unit 330 is formed to suppress leakage of the permanent magnet 322 between the poles so that the surface magnetic flux density becomes a sine wave. The magnetic flux control unit 330 is provided for each electromagnetic steel sheet constituting the rotor core 321.

  As shown in FIG. 31, the magnetic flux control unit 330 is formed on the outer peripheral iron core of each magnet insertion hole 323, and has a plurality of long hole-shaped magnetic flux control units 330 a to 330 d and a magnet insertion hole 323. It is connected to the end portion, is formed at the inter-pole portion, and is constituted by a polygonal magnetic flux control unit 330e in plan view.

  The magnetic flux control units 330a to 330e are different from the magnetic flux control units 30a to 30e shown in FIG. 12 in that each of the magnetic flux control units 330a to 330e includes a zero-thickness region and a thin portion. Furthermore, a thin part is arrange | positioned at the outer peripheral side of the rotor 320 of the magnetic flux control parts 330a-330e. As for the magnetic flux control parts 330a-330e, the inner side of the thin part is an area | region where plate | board thickness is zero.

  The magnetic flux control unit 330a is located on the magnetic pole center line, and magnetic flux control units 330b to 330d are sequentially formed between the left and right poles with the magnetic flux control unit 330a as a center. The magnetic flux control units 330 b to 330 d are oriented in a direction in which the outward extension line intersects the magnetic pole center line outside the rotor 320. Since the magnetic flux of the permanent magnet 322 is controlled as described above by the magnetic flux control units 330a to 330d, the magnetic flux density on the surface of the rotor 320 has a waveform close to a sine wave. In addition, the circumferential direction width | variety of the magnetic flux control parts 330a-330d is about 2 mm, for example.

  The configuration will be further described by taking the magnetic flux controller 330a as an example. As shown in FIGS. 32 and 33, the magnetic flux controller 330a includes a thin portion 330a-1 and a punched portion 330a-2 (a region having a zero plate thickness).

  The effect of making the magnetic flux difficult to flow is more effective as the plate thickness is thinner. However, since the mechanical strength decreases when punched, the surface portion of the rotor 320 of the weakly punched portion 330a-2 is thinned with a thin plate thickness. By comprising 330a-1, the strength reduction of the rotor 320 can be suppressed.

Embodiment 2. FIG.
34 to 37 show the second embodiment. FIG. 34 is a transverse sectional view of the rotor 420, FIG. 35 is a transverse sectional view of the rotor core 421, FIG. 36 is a partially enlarged view of FIG. FIG. 37 is a sectional view taken along line GG in FIG. 36.

  As shown in FIG. 34, the rotor 420 is a permanent magnet embedded type, and includes at least a rotor core 421 and a plate-shaped permanent magnet 422 inserted into the magnet insertion hole 423 of the rotor core 421.

  The six permanent magnets 422 are inserted into magnet insertion holes 423 formed along the outer peripheral edge of the rotor core 421 to constitute a six-pole rotor 420.

  The permanent magnet 422 of the rotor 420 is mounted with a neodymium rare earth magnet mainly composed of Nd—Fe—B (neodymium, iron, boron) and has a flat plate shape with a thickness of about 2 mm.

  As shown in FIG. 35, the rotor core 421 has a substantially columnar shape, and six magnet insertion holes 423 having a substantially rectangular cross section are formed along the outer peripheral edge. In the cross section, the six magnet insertion holes 423 form a substantially hexagonal shape. A shaft hole 424 into which a rotating shaft (not shown) is inserted is provided at a substantially central portion of the rotor core 421.

  The rotor core 421 is configured by forming a thin electromagnetic steel sheet having a thickness of 0.7 mm or less into a predetermined shape and laminating a predetermined number of sheets.

  The rotor core 421 controls the magnetic flux of the permanent magnet 422 at the outer peripheral core portion and the pole portion outside each magnet insertion hole 423 (so that the magnetic flux density on the surface of the rotor 420 becomes a sine wave). 430 is formed. The magnetic flux control unit 430 having a reduced plate thickness is provided for each electromagnetic steel plate constituting the rotor core 421.

  The magnetic flux controller 430 is configured so that the radial width gradually increases from the magnetic pole center toward the inter-pole. Specifically, the inner periphery of the magnetic flux control unit 430 has a substantially sinusoidal petal shape in which the magnetic pole part is convex outward and the inter-polar part is concave outward (see, for example, the enlarged view of FIG. 36). .

  As shown in FIG. 37, the thickness W0 of the electromagnetic steel plate 421a constituting the rotor core 421 is configured to be 0.35 mm, for example, and the thickness W1 of the magnetic flux controller 430 is configured to be 0.1 mm, for example. ing. The magnetic flux control unit 430 is constituted by each electromagnetic steel plate 421a, and the rotor core 421 of the present embodiment fixes the phase of the electromagnetic steel plates 421a by caulking and is laminated in the axial direction.

  Since the magnetic flux control unit 430 has a small plate thickness (for example, 0.1 mm), it is difficult for the magnetic flux to pass therethrough. For this reason, the magnetic pole portion can be configured to have a high magnetic flux density and the inter-pole portion can have a low magnetic flux density, which has the effect of making the magnetic flux density distribution on the surface of the rotor 420 sinusoidal.

  38 and 39 are diagrams showing the second embodiment. FIG. 38 is a diagram showing a waveform of an induced voltage induced in the stator winding when the magnetic flux control unit of the rotor 420 is provided. FIG. It is the figure which compared the harmonic component content rate of the induced voltage induced by the coil | winding of a stator with and without a magnetic flux control part.

  As shown in FIG. 38, in the case where the magnetic flux control unit 430 of the rotor 420 is provided, the waveform of the induced voltage induced in the stator winding is a waveform very close to a sine wave.

  As shown in FIG. 39, the harmonic content of the induced voltage (the value obtained by dividing the square root of the square sum of the amplitudes of the harmonic components by the amplitude of the fundamental component) is 7.6% without the magnetic flux control unit 430. The magnetic flux control unit 430 is 2.6%, which is reduced to about 1/3.

  By configuring as described above, it is possible to reduce the harmonic component of the generated torque, and it is possible to configure a motor with low vibration and high efficiency. Further, since the harmonic component of the magnetic flux density is reduced, it is possible to reduce the iron loss caused by the magnetic fluctuation of the harmonic component, and it is possible to configure a highly efficient electric motor.

  In addition, since a magnetic attraction force acts between the stator and the rotor in the permanent magnet motor, vibration is likely to occur due to manufacturing variations due to eccentricity or the like, and the air gap is managed. When the above configuration is performed by punching, that is, when the magnetic flux control unit 430 is punched, the air gap between the stator and the rotor 420 becomes non-uniform, so air gap management for examining eccentricity becomes difficult. In this embodiment, since the outer periphery of the rotor 420 is a perfect circle, there is an advantage that the air gap is constant and the gap management is easy.

Embodiment 3 FIG.
FIG. 40 is a longitudinal sectional view of the rotary compressor 500 showing the third embodiment. For example, a brushless DC motor using the rotors 20, 120, 220, and 320 of the first embodiment and the rotor 420 of the second embodiment is mounted on the compressor for refrigeration and air conditioning. Since the brushless DC motor constitutes an electric motor with low vibration and high efficiency and is a highly reliable electric motor with improved mechanical strength against centrifugal force, an excellent compressor can be obtained.

  Hereinafter, a rotary compressor 500 (an example of a compressor) equipped with the electric motor 100 of the first embodiment will be described with reference to FIG. However, an electric motor (brushless DC motor) using the rotors 120, 220, and 320 of the first embodiment and the rotor 420 of the second embodiment may be used.

  An example of the rotary compressor 500 shown in FIG. 40 is a vertical type in which the inside of the sealed container 70 is high pressure. A compression element 501 is housed in the lower part of the sealed container 70. An electric motor 100 (see FIG. 9), which is an electric element that drives the compression element 501, is accommodated above the compression element 501 in the upper part of the sealed container 70.

  Refrigerating machine oil 90 that lubricates the sliding portions of the compression element 501 is stored at the bottom of the sealed container 70.

  First, the configuration of the compression element 501 will be described. The cylinder 1 in which the compression chamber is formed has a cylinder chamber (not shown) that is a space having a substantially circular outer periphery in a plan view and a substantially circular space in a plan view. The cylinder chamber is open at both axial ends. The cylinder 1 has a predetermined axial height in a side view.

  Parallel vane grooves (not shown) that communicate with a cylinder chamber that is a substantially circular space of the cylinder 1 and extend in the radial direction are provided so as to penetrate in the axial direction.

  A back chamber (not shown), which is a substantially circular space in plan view, communicates with the vane groove is provided on the back surface (outside) of the vane groove.

  An intake port (not shown) through which intake gas from the refrigeration cycle passes through the cylinder 1 passes through the cylinder chamber from the outer peripheral surface of the cylinder 1.

  The cylinder 1 is provided with a discharge port (not shown) in which the vicinity of the edge of the circle forming the cylinder chamber which is a substantially circular space (end surface on the side of the electric motor 100) is cut out.

  The material of the cylinder 1 is gray cast iron, sintered, carbon steel or the like.

  The rolling piston 2 rotates eccentrically in the cylinder chamber. The rolling piston 2 has a ring shape, and the inner periphery of the rolling piston 2 is slidably fitted to the eccentric shaft portion 50 a of the rotating shaft 50.

  It is assembled so that there is always a constant gap between the outer periphery of the rolling piston 2 and the inner wall of the cylinder chamber of the cylinder 1.

  The material of the rolling piston 2 is alloy steel containing chromium or the like.

  The vane 3 is accommodated in the vane groove of the cylinder 1, and the vane 3 is always pressed against the rolling piston 2 by the vane spring 8 provided in the back pressure chamber. In the rotary compressor 500, since the inside of the sealed container 70 is at a high pressure, when the operation is started, a force due to a differential pressure between the high pressure in the sealed container 70 and the pressure in the cylinder chamber acts on the back surface (back pressure chamber side) of the vane 3. Therefore, the vane spring 8 is mainly used for the purpose of pressing the vane 3 against the rolling piston 2 when the rotary compressor 500 is started up (in a state where there is no difference in pressure between the inside of the sealed container 70 and the cylinder chamber).

  The shape of the vane 3 is a flat shape (the thickness in the circumferential direction is smaller than the length in the radial direction and the axial direction).

  High-speed tool steel is mainly used as the material of the vane 3.

  The main bearing 4 is slidably fitted into a main shaft portion 50b (a portion above the eccentric shaft portion 50a and a portion fitting with the rotor 20) of the rotating shaft 50, and a cylinder chamber (vane groove) of the cylinder 1. One end surface (including the electric motor 100 side) of the motor is closed.

  The main bearing 4 includes a discharge valve (not shown). However, it may be attached to either one or both of the main bearing 4 and the sub-bearing 5.

  The main bearing 4 has a substantially inverted T shape when viewed from the side.

  The sub-bearing 5 is slidably fitted to the sub-shaft portion 50c (a portion below the eccentric shaft portion 50a) of the rotating shaft 50, and the other end face (freezing) of the cylinder chamber (including the vane groove) of the cylinder 1 is also provided. The machine oil 90 side) is closed.

  The secondary bearing 5 is substantially T-shaped in a side view.

  The material of the main bearing 4 and the sub bearing 5 is the same as that of the cylinder 1, and is made of gray cast iron, sintered, carbon steel, or the like.

  A discharge muffler 7 is attached to the main bearing 4 on the outer side (motor 100 side). The high-temperature and high-pressure discharge gas discharged from the discharge valve of the main bearing 4 enters the discharge muffler 7 at one end and is then discharged from the discharge muffler 7 into the sealed container 70. However, the discharge muffler 7 may be provided on the sub-bearing 5 side.

  A suction muffler 51 is provided beside the hermetic container 70 to suck low-pressure refrigerant gas from the refrigeration cycle and prevent liquid refrigerant from being directly drawn into the cylinder chamber of the cylinder 1 when the liquid refrigerant returns. The suction muffler 51 is connected to the suction port of the cylinder 1 via the suction pipe 52. The main body of the suction muffler 51 is fixed to the side surface of the sealed container 70 by welding or the like.

  A terminal 74 (referred to as a glass terminal) connected to a power source that is a power supply source is fixed to the sealed container 70 by welding. In the example of FIG. 40, a terminal 74 is provided on the upper surface of the sealed container 70. A lead wire 73 from the electric motor 100 that is an electric element is connected to the terminal 74.

  A discharge pipe 75 having both ends opened is inserted into the upper surface of the sealed container 70. The discharge gas discharged from the compression element 501 is discharged from the sealed container 70 through the discharge pipe 75 to the external refrigeration cycle.

  A general operation of the rotary compressor 500 will be described. When electric power is supplied from the terminal 74 and the lead wire 73 to the stator 10 of the electric motor 100 which is an electric element, the rotor 20 rotates. Then, the rotating shaft 50 fixed to the rotor 20 rotates, and accordingly, the rolling piston 2 rotates eccentrically in the cylinder chamber of the cylinder 1. A space between the cylinder chamber of the cylinder 1 and the rolling piston 2 is divided into two by a vane 3. As the rotary shaft 50 rotates, the volume of these two spaces changes, the volume gradually increases on one side and the refrigerant is sucked in from the suction muffler 51, and the volume gradually decreases on the other side. The refrigerant gas is compressed. The compressed discharge gas is discharged once from the discharge muffler 7 into the sealed container 70, further passes through the electric motor 100 as an electric element, and is discharged out of the sealed container 70 through the discharge pipe 75 on the upper surface of the sealed container 70. .

  The discharge gas that passes through the electric motor 100, which is an electric element, is, for example, a void 40 (see FIG. 9) including an air hole (through hole) of the rotor 20 of the electric motor 100 (not shown) and a slot opening (not shown) of the stator 10. ), And passes through a notch (see FIG. 9) disposed on the outer periphery of the stator 10.

  1 Cylinder, 2 Rolling piston, 3 Vane, 4 Main bearing, 5 Sub bearing, 7 Discharge muffler, 8 Vane spring, 10 Stator, 20 Rotor, 21 Rotor core, 21a Electrical steel plate, 22 Permanent magnet, 23 Magnet insertion Hole, 24 shaft hole, 30 magnetic flux control unit, 30a-30e magnetic flux control unit, 40 air gap, 50 rotating shaft, 50a eccentric shaft part, 50b main shaft part, 50c secondary shaft part, 51 suction muffler, 52 suction pipe, 70 airtight container 73 lead wire, 74 terminal, 75 discharge pipe, 90 refrigerating machine oil, 100 electric motor, 120 rotor, 121 rotor core, 122 permanent magnet, 123 magnet insertion hole, 130 magnetic flux control unit, 130a to 130e magnetic flux control unit, 220 Rotor, 221 Rotor core, 222 Permanent magnet, 223 Magnet insertion hole, 230 Magnetic flux controller, 2 0a to 230e Magnetic flux control unit, 320 rotor, 321 rotor core, 322 permanent magnet, 323 magnet insertion hole, 330 magnetic flux control unit, 330a magnetic flux control unit, 330a-1 thin portion, 330a-2 punching unit, 330b to 330e Magnetic flux control unit, 420 Rotor, 421 Rotor core, 422 Permanent magnet, 423 Magnet insertion hole, 424 Shaft hole, 430 Magnetic flux control unit, 500 Rotary compressor, 501 Compression element, 600 Electric motor, 610 Stator, 611 Stator Iron core, 612 winding, 613 teeth, 614 slot, 614a slot opening, 615 core back, 620 rotor, 621 rotor core, 622 permanent magnet, 623 magnet insertion hole, 624 shaft hole, 640 gap, 720 rotor, 721 Rotor core, 722 permanent magnet, 723 magnet Insertion hole, 725 slit, 725a to 725d slit.

Claims (8)

An electric motor comprising a stator and a permanent magnet embedded rotor,
The rotor is
A rotor core in which a plurality of magnet insertion holes are formed along the outer periphery;
A plurality of permanent magnets inserted into the magnet insertion holes,
The rotor core is formed by laminating a predetermined number of electromagnetic steel plates each having a magnetic flux control unit formed by reducing the plate thickness at the outer peripheral core part outside the magnet insertion hole and between the poles. An electric motor characterized by that.   2. The electric motor according to claim 1, wherein the magnetic flux control unit formed in the outer peripheral core part outside the magnet insertion hole is formed in a long hole shape in a plan view.   The electric motor according to claim 1, wherein the magnetic flux control unit is in contact with the magnet insertion hole or the outer periphery of the rotor.   The electric motor according to claim 1, wherein the plurality of magnetic flux control units have different plate thicknesses.   2. The electric motor according to claim 1, wherein each magnetic flux control unit includes a thin-walled portion and a punched portion that is a region having a plate thickness of zero.   2. The electric motor according to claim 1, wherein the magnetic flux control unit is formed to gently spread from the magnetic pole part toward the inter-pole part.   The electric motor according to claim 1, wherein the magnetic flux control unit is formed by etching.   A compressor equipped with the electric motor according to claim 1.

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