JP5337769B2 - Electric motor, hermetic compressor equipped with the same, and refrigerator equipped with the same - Google Patents

Description

  The present invention relates to an electric motor, a hermetic compressor including the electric motor, and a refrigerator including the electric motor.

  In a permanent magnet type electric motor, there is a method for improving the residual magnetic flux density of the permanent magnet and increasing the gap magnetic flux density as one means for improving the efficiency. Conventionally, in order to achieve high efficiency with an inexpensive permanent magnet having a low magnetic flux density such as a ferrite magnet, a structure as disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-44889 (Patent Document 1) has been proposed. . According to FIG. 2, the magnetic field lines from the permanent magnets are generated in the directions of M1, M2, and M3 by using the arc segment-shaped permanent magnets having the triaxial anisotropy indicated by 25a to 25d as the rotor. The amount of effective magnetic flux is increased by focusing on the outer peripheral surface of the rotor and forming one magnetic pole.

JP 2002-44889 A

  However, when the efficiency is increased in this structure, the difference in height of the magnetic flux density in the gap increases, and this increases the difference between the maximum value and the minimum value (pulsation torque) of the noise generated by the motor. Cause.

  Accordingly, an object of the present invention is to provide an electric motor that achieves high efficiency and suppresses noise, a hermetic compressor including the electric motor, and a refrigerator including the electric motor.

In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above problems. For example, a magnet embedded in which a plurality of permanent magnets are embedded at equal intervals in a rotor core formed by stacking disc-shaped electromagnetic steel sheets. In the electric motor including the rotor of the type, the permanent magnet has a triaxial anisotropic shape, and the rotor is divided into a plurality of sections in the axial direction so that the amplitude of the cogging torque becomes a predetermined magnitude, and both ends of the interval of the plurality of sections is a periphery arcuate outer periphery of the central segments of the plurality of sections is characterized in that have a groove width corresponding to the phase difference of the cogging torque .

  ADVANTAGE OF THE INVENTION According to this invention, efficiency improvement can be achieved and the electric motor which suppressed the noise, the hermetic compressor provided with the same, and the refrigerator provided with the same can be provided.

The radial direction sectional view of the permanent magnet type electric motor concerning the embodiment of the present invention. The figure which shows the prior art example of a triaxial anisotropic shape magnet. A radial direction sectional view of a rotor iron core concerning an embodiment of the present invention. The external view of the rotor core which concerns on embodiment of this invention, and the division | segmentation figure of a rotor. Detailed drawing of the rotor electromagnetic steel plate which concerns on embodiment of this invention. Detailed drawing of the rotor electromagnetic steel plate which concerns on embodiment of this invention. Torque generated from the electric motor according to the embodiment of the present invention. 1 is a cross-sectional view of a hermetic compressor according to an embodiment of the present invention. The cross section of the refrigerator which concerns on embodiment of this invention.

  An embodiment of the present invention will be described with reference to FIGS. 1, 3, 4 and 5. FIG. FIG. 1 is a radial sectional view of a permanent magnet electric motor. FIG. 3 is an enlarged view of the rotor. FIG. 4 is a perspective three-dimensional view of the rotor. FIG. 5 is an enlarged view of the outer periphery of the rotor core.

  The 6-pole 9-slot permanent magnet motor 1 shown in FIG. 1 includes a stator 2 and a rotor 3. The stator 2 includes a stator core 6 having a tooth 4 and a slot 5, and an armature winding 7 wound around the tooth 4 by concentrated winding.

  As shown in FIG. 3, the rotor 3 has a three-axis anisotropic magnet 10 inserted into a disc-shaped rotor core 9 having a permanent magnet insertion hole 8 having a three-axis anisotropic shape, and the rotor 3 is centered on the rotor 3. Has a shaft hole 11 for fitting the shaft.

  As shown in FIG. 4, the rotor 3 is divided into three sections in the axial direction (section A, section B, and section C from the top surface of the rotor, respectively).

  In the rotor 3 in the section A, a plurality of disk-like rotor electromagnetic steel plates 13 shown in FIG. The outer periphery of the electromagnetic steel sheet 12 forms an arc.

  In the rotor 3 in the section B, a plurality of rotor electromagnetic steel plates 13 shown in FIG. In addition to the outer peripheral shape of the electromagnetic steel plate 12, the rotor electromagnetic steel plate 13 is provided with two grooves 14a and 14b on the outer peripheral portion in the vicinity of the permanent magnet insertion hole 8 so as to be substantially symmetrical with respect to the magnetic pole center. Yes.

  The rotor 3 in the section C has the same configuration as the rotor 3 in the section A (see FIG. 5).

  Next, FIG. 6 shows the torque generated in the rotor 3. (1) When the rotors are all laminated with the electromagnetic steel plates 12 without the outer peripheral groove, (2) When all the rotors are laminated with the rotor electromagnetic steel plates 13 with grooves, and (3) The electromagnetic steel plates 12 and the rotor electromagnetic This is a case where the axial lengths of the steel plates 13 are laminated so that the amplitude of the cogging torque generated from each of them is the same.

  The groove width is adjusted to about 6 ° so that the cogging torque generated in the rotor 3 in the sections A and C and the cogging torque generated in the section B in FIG.

  Further, by setting the interval between adjacent grooves to about 10 ° from the center of the magnet, the magnetic flux generated from the permanent magnet is concentrated in the direction of the magnetic pole center, and magnetic flux saturation does not occur. As a result, the torque of the motor can be improved and the efficiency can be increased, and the pulsating torque that causes noise can be reduced by about 30%.

  Next, the longitudinal cross-sectional view of the hermetic compressor 50 of this embodiment is shown in FIG.

  The hermetic compressor 50 according to the present embodiment is a reciprocating compressor in which the compression element 30 and the electric element 40 are vertically arranged in the hermetic container 15 and connected by the crankshaft 16. The compression element 30 and the electric element 40 are elastically supported by the sealed container 15.

  The compression element 30 includes a cylinder 17 that forms a cylinder chamber, a piston 18 that reciprocates in the cylinder chamber, a connecting rod 19 that drives the piston 18, and a number of components that are assembled on the cylinder end face. . The cylinder 17 is integrally formed with a bearing portion 17a and a frame 17b. The piston 18 is connected to the crank pin 16a via the connecting rod 19, and is reciprocated in the cylinder 17 by the eccentric rotation of the crank pin 16a.

  The electric element 40 is disposed below the frame 17 b and includes the stator 2 and the rotor 3. The stator 2 is fixed to the frame 17b, and the rotor 3 is fixed to the crankshaft 16. A crankpin 16 a that is eccentric from the center of rotation is provided at the upper end of the crankshaft 16.

  The crankshaft 16 passes through the bearing portion 17a and extends upward from below the frame 17b, and the crankpin 16a is provided so as to be positioned above the frame 17b. The lower part of the crankshaft 16 is directly connected to the rotor 3, and the crankshaft 16 is rotated by the power of the electric element 40. The crank pin 16a and the piston 18 are connected by a connecting rod 19, and the piston 18 is reciprocated through the crank pin 16a and the connecting rod 19.

  The gas refrigerant supplied into the cylinder 17 is compressed by the reciprocating motion of the piston 18. The compressed gas refrigerant is sent to the discharge pipe via the discharge hole provided in the valve plate. The refrigerant sent to the discharge pipe returns to the compressor again through the condenser, the pressure reducing mechanism, and the evaporator. A refrigeration cycle is formed by a compressor, a condenser, a pressure reducing mechanism, and an evaporator. In this refrigeration cycle, a hydrocarbon-based refrigerant (HC refrigerant) such as isobutane (R600a) is used.

  Refrigerating machine oil (lubricating oil) is stored in the sealed container 15, and is pulled up by a pump action by the rotational movement of the crankshaft 16 and sent to the sliding portion of the compression element 30.

  In addition, as shown in FIG. 8, by installing the hermetic compressor 50 in the refrigerator 100, noise can be reduced, cooling efficiency can be improved, and power consumption of the refrigerator 100 can be reduced.

  As described above, according to the present invention, in the electric motor including the rotor with a magnet embedded in which a plurality of permanent magnets are embedded at equal intervals in a rotor core formed by laminating disc-shaped electromagnetic steel plates, the permanent magnet Has a three-axis anisotropic shape, and the rotor is divided into a plurality of sections in the axial direction, and has a groove on the outer periphery having a width corresponding to the phase difference of cogging torque generated in each of the plurality of sections. That is, the axial length of the divided rotor is adjusted so that the amplitude of the cogging torque generated in each section is the same, and the width of the groove is the phase difference of the cogging torque generated from each section. The cogging torque can be attenuated by adjusting so that the angle becomes 180 °.

  Further, the position and depth of the groove are adjusted so that the magnetic flux generated from the permanent magnet is concentrated on the magnetic pole side. That is, the axial length of the groove is provided so that the cogging torque has a predetermined amplitude. Further, an interval is provided so that the field magnetic flux generated from the permanent magnet and directed to the armature winding of the stator is not magnetically saturated. Thereby, a magnetic flux short circuit can be suppressed and it can be set as an electric motor with few losses.

  Therefore, in a permanent magnet electric motor composed of a stator provided with armature windings and a rotor inserted with a permanent magnet having a triaxial anisotropic shape as shown in FIG. Noise can be reduced by increasing the efficiency and canceling the torque pulsation that accompanies it.

DESCRIPTION OF SYMBOLS 1 Permanent magnet type motor 2 Stator 3 Rotor 4 Teeth 5 Slot 6 Stator iron core 7 Armature winding 8 Permanent magnet insertion hole 9 Rotor iron core 10 Triaxial anisotropic magnet 11 Shaft hole 12 Electrical steel plate 13 Rotation Magnetic steel sheet 14a, 14b Groove 50 Sealed compressor 100 Refrigerator

Claims (5)

In an electric motor equipped with a magnet-embedded rotor in which a plurality of permanent magnets are embedded at equal intervals in a rotor core formed by laminating disc-shaped electromagnetic steel plates,
The permanent magnet has a triaxial anisotropic shape, and the rotor is divided into a plurality of sections in the axial direction so that the amplitude of the cogging torque becomes a predetermined magnitude, and sections at both ends of the plurality of sections. motor outer periphery a circular arc shape, the outer circumference of the central segments of the plurality of sections is characterized by have a groove width corresponding to the phase difference of the cogging torque.   The electric motor according to claim 1, wherein the axial length of the groove is provided such that the cogging torque has a predetermined amplitude.   2. The electric motor according to claim 1, wherein a space is provided so that a field magnetic flux generated from the permanent magnet and directed to the armature winding of the stator is not magnetically saturated.   A hermetic compressor comprising the electric motor according to any one of claims 1 to 3.   A refrigerator comprising the hermetic compressor according to claim 4.

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