JP4096254B2 - Permanent magnet type motor and compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor used in a compressor such as a refrigerator, a dehumidifier, and an air conditioner, and a compressor using the motor.
[0002]
[Prior art]
In recent years, motors for driving compressors for air conditioners and refrigerators have used permanent magnet motors that can easily control the number of rotations and have high motor efficiency.
For example, the permanent magnet type motor has been implemented as follows in order to prevent vibration and noise during operation of the compressor.
In order to correct the unbalance of the output shaft end of the shaft, balance weights are provided on both sides of the rotor, the axial length of the rotor core is made larger than the axial length of the stator core, and the axial center of the rotor core is Shift to the non-output side from the axial center. (For example, refer to Patent Document 1).
[0003]
[Patent Document 1]
JP 2000-134882 (5th page, 6th page, FIG. 3)
[0004]
[Problems to be solved by the invention]
As described above, the conventional permanent magnet type motor for driving the compressor is configured such that the axial length of the rotor core portion is larger than the axial length of the stator core portion. When the embedded magnet rotor is used, the magnetic flux produced by the permanent magnet is passed through the thin connecting portion of the outer periphery between the magnet poles at the end of the rotor core in the axial direction. The short-circuit magnetic flux (Φ1) on the path to the permanent magnet is generated, the effective magnetic flux contributing to the torque is reduced, the current for obtaining the desired torque is increased, and the copper loss is increased (Problem A).
[0005]
In addition, the magnetic flux generated by the current flowing through the stator windings generates a leakage magnetic path that passes through the outer peripheral end in the axial direction of the rotor core, so that more current is required to obtain the desired torque. The copper loss was increased (Problem B).
[0006]
Furthermore, since the coil end portion of the stator winding and the rotor core portion are arranged to face each other, the magnetic flux (Φ2) generated by the current flowing in the stator winding changes perpendicularly to the end portion of the rotor core portion. An eddy current loss occurs at the end of the rotor core that faces the coil end of the stator winding, increasing the iron loss (Problem C).
[0007]
Further, even if the material of the end portion of the rotor core portion facing the coil end portion of the stator winding is made of a nonmagnetic metal material, the eddy current is generated in the nonmagnetic metal material. Generated and increased iron loss.
[0008]
Also, if the material of the end of the rotor core facing the coil end of the stator winding is made of non-magnetic resin, the balance weight will be high to obtain a sufficient moment, and the compressor will It was getting bigger.
[0009]
As described above, even if the conventional permanent magnet type motor can suppress the vibration and noise, it was made to solve the problem that the copper loss and the iron loss caused the decrease in efficiency at the same time. An object of the present invention is to suppress a decrease in efficiency of a permanent magnet motor and to suppress vibration and noise. Another object of the present invention is to obtain a compressor with high efficiency and low vibration and noise by using this permanent magnet type motor.
[0010]
[Means for Solving the Problems]
The present invention provides a high-density member made of magnetic metal at the axial end of the rotor core, and the outer shape corresponding to the axial direction of the high-density member and the magnet insertion hole of the rotor core in the cross-section perpendicular to each axis. When the dimensions are D3 and D4, it is a permanent magnet type motor in which D3 ≦ D4 and a compressor using this permanent magnet type motor.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view of a compressor incorporating a permanent magnet type motor for driving a compressor according to Embodiment 1 of the present invention. FIG. 2 is a transverse sectional view of a rotor of the permanent magnet type motor. FIG. 3 is a view showing the compression mechanism of the compressor.
In these drawings, the compressor has a permanent magnet type motor composed of a stator 5 and a rotor 6 arranged in the upper part of the hermetic container 7, a compression mechanism part 15 arranged in the lower part, and both are connected by a drive shaft 13, The drive shaft 13 is rotated by a permanent magnet type motor, the compression mechanism unit 15 is operated, and the sucked refrigerant is compressed.
[0012]
The stator 5 of the permanent magnet type motor includes a stator core portion 5a which is a hollow laminated body in which a plurality of disk-shaped electromagnetic steel plates having a thickness of about 0.3 to 0.5 mm with an opening at the center are laminated in the axial direction, and the stator core portion 5a. Consists of upper and lower coil end portions 5b, and the stator core portion 5a is disposed so as to surround the rotor 6 disposed in the center with the gap 12 therebetween, and the outer peripheral side is sealed by means such as shrink fitting or welding. Attached directly to the container 7 and held. The stator core portion 5 of the stator 5 is provided with a plurality of slots (not shown), in which coils are wound, and windings 11 such as distributed windings or concentrated windings are applied.
[0013]
The rotor 6 is attached to the rotor core 6a fixed to the drive shaft 13 passing through the center in the axial direction and the upper and lower ends of the rotor core 6a, and similarly fixed to the drive shaft 13 passing through the center in the axial direction. The high-density member portion 6b made of a high-density member.
The rotor core portion 6a is formed by laminating a plurality of disc-shaped electromagnetic steel plates having a thickness of about 0.3 to 0.5 mm with an opening at the center in the axial direction. In the rotor core portion 6a, a plurality of magnet insertion holes 9 are provided in the axial direction about the drive shaft 13 on the plane orthogonal to the drive shaft 13, and the permanent magnet 10 is inserted over the entire axial direction of the rotor core portion 6a. Is done. As the permanent magnet 10, a sintered rare earth magnet mainly composed of neodymium, iron, boron or the like is used.
The stator core portion 5a and the rotor core portion 6a are formed concentrically in the direction of the drive shaft 13 by providing a predetermined gap portion 12 with the rotor core portion 6a in the middle.
[0014]
The high-density member portion 6b attached to the upper end and the lower end of the rotor core portion 6a is a hollow cylindrical body having an outer diameter smaller than the outer diameter of the rotor core portion 6a by a predetermined amount. The high density member 6b is made of a nonmagnetic metal. That is, brass (alloy of copper and zinc), which is a nonmagnetic metal material, is used. In addition, copper, palladium, tungsten, nickel chloride, stainless steel, or the like may be used as long as it is a high-density nonmagnetic material.
The compression mechanism 15 side of the drive shaft 13 that passes through and is fixed to the center of the rotor core 6a and the high-density member 6b is rotatably held by bearings 14 and 14 below the hermetic container 7.
[0015]
Next, as shown in FIG. 1, the dimensional relationship between the stator 5 and the rotor 6 will be described.
The axial length L1 of the rotor core portion 6a of the rotor 6 is substantially the same as the axial length L2 of the stator core portion 5a of the stator 5, and the outer diameter D1 of the rotor core portion 6a is formed at both ends of the rotor core portion 6a. A high-density member portion 6b having an outer diameter D2 that is smaller by a predetermined amount is attached, and the axial length L3 of the rotor 6 including the high-density member portion 6b is larger by a predetermined amount than the axial length L2 of the stator core portion 5a. It comprised so that it might become.
For example, the outer diameter D2 of the high-density member 6b is configured to be approximately 0.95 times or less than the outer diameter D1 of the rotor core 6a. That is, the outer diameter D2 of the high-density member 6b is high enough to prevent leakage magnetic flux Φ2 generated from the coil end 5b when the permanent magnet type motor is driven, from interlinking with the high-density member 6b. The outer diameter D2 of the density member portion 6b is configured to be small.
[0016]
If the axial length L3 of the rotor 6 including the high-density member portion 6b is increased by a predetermined amount with respect to the axial length L2 of the stator core portion 5a, the high-density member portion 6b becomes the rotor core portion. It does not need to be attached to both the upper end and the lower end of 6a, and may be attached to either one end.
Further, the axial length L1 of the rotor core portion 6a of the rotor 6 is not substantially the same as the axial length L2 of the stator core portion 5a of the stator 5, and the axial length L1 of the rotor core portion 6a is set to the stator core. You may make it longer than the length L2 of the axial direction of the part 5a.
The axial length L1 of the rotor core portion 6a is made longer than the axial length L2 of the stator core portion 5a, and the permanent magnet 10 having substantially the same length as the axial length L1 of the rotor core portion 6a is provided. Thus, the magnetic flux passing through the outer periphery of the rotor core portion 6a and interlinking with the stator core portion 5a can be increased, the current for obtaining the same torque can be reduced, and the copper loss can be reduced. The longer the axial length L1 of the rotor core portion 6a, the larger the magnetic force does not increase, and the magnetic flux does not increase beyond a certain length. That is, it is desirable that the length L1 is 1.4 times or less of the length L2.
[0017]
Further, the axial length L3 of the rotor 6 including the high density member portion 6b is about 2 to 3 times the axial length L2 of the stator core portion 5a when a rare earth magnet is used as the permanent magnet 10 of the rotor 6. It is comprised so that it may become. The axial length L3 of the rotor 6 is configured to be approximately equal to the rotor core width required to obtain the same efficiency when the rotor 6 is configured using a ferrite magnet. That is, the axial length is designed to be smaller by using rare earth magnets than when using ferrite magnets.
[0018]
Further, the outer peripheral portion of the compression mechanism portion 15 is directly attached to the sealed container 7 and fixed. As shown in FIG. 3, the compression mechanism portion 15 is rotatably fitted in a cylinder 18 having a cylinder chamber in which a suction port 16 and a discharge port 17 are opened, and an eccentric shaft portion of the drive shaft 13, and is disposed in the cylinder 18. And a vane 22 that is provided integrally with the piston 19 and is divided into a low pressure chamber 20 of a compression chamber that communicates the cylinder chamber with the suction port 16 and a high pressure chamber 21 of the compression chamber that communicates with the discharge port 17. Has been.
[0019]
When the drive shaft 13 of the permanent magnet type motor is driven to rotate by the inverter, the piston 19 rotates in conjunction with this, and the refrigerant gas is sucked into the cylinder chamber from the suction port 16 and compressed and discharged from the discharge port 17. At this time, the drive shaft 13 of the permanent magnet type motor is accompanied by a large pressure fluctuation (drive torque fluctuation) during one rotation as shown in FIG.
[0020]
FIG. 5 shows a current waveform when this motor is driven by a 120-degree rectangular wave drive using an inverter. FIG. 5A shows a case where the high-density member portion 6b is not attached, and FIG. 5B shows a motor current waveform when the high-density member portion 6b is attached.
As shown in the comparison between the two figures, a large current pulsation was generated during one rotation when the high-density member portion 6b was not attached, whereas by attaching the high-density member portion 6b as described above, 1 Current pulsation during rotation can be reduced and current can be made uniform.
That is, the axial length L1 of the rotor core portion 6a is substantially the same as the axial length L2 of the stator core portion 5a, and high-density member portions 6b made of a metal nonmagnetic material are provided at both ends of the rotor core portion 6a. By providing, the inertia force of the rotor 6 can be increased and the vibration and noise of the motor can be suppressed.
The axial length L1 of the rotor core 6a is made longer than the axial length L2 of the stator core 5a, and the permanent magnet 10 having substantially the same length as the axial length L1 of the rotor core 6a is provided. Even if it is provided, the same effect can be obtained.
Further, the high-density member portion 6b is not limited to a non-magnetic metal, and if it is made of a high-density member, the inertia force of the rotor 6 can be increased similarly.
Further, the driving method is not limited to the 120 ° rectangular wave driving, and the same effect can be obtained by any other driving method such as a rectangular wave driving of 120 ° or more and a sine wave driving.
[0021]
Further, the axial lengths of the rotor core portion 6a and the stator core portion 5a are made substantially the same in the axial direction, or the axial length of the rotor core portion 6a provided with the permanent magnet 10 having the substantially same length is set as the stator core. Since the material of the high-density member portion 6b which is longer than the axial length of the portion 5a and is provided at the end of the rotor core portion 6a is made of nonmagnetic metal, the permanent portion provided inside the rotor core portion 6a. The leakage flux Φ1 of the path through which the magnetic flux generated by the magnet 10 passes through the adjacent magnet pole 10a through the high-density member portion 6b does not occur, that is, the short-circuit flux Φ1 does not occur, and the copper loss can be reduced (that is, the problem) A can be eliminated).
[0022]
Further, the axial lengths of the rotor core portion 6a and the stator core portion 5a are made substantially the same in the axial direction, or the axial length of the rotor core portion 6a provided with the permanent magnet 10 having the substantially same length is set as the stator core. It is longer than the axial length of the portion 5a, and the outer diameter dimensional relationship between the non-magnetic metal high-density member portion 6b and the rotor core portion 6a is D2 <D1, that is, the outer diameter of the high-density member portion 6b. By making the dimension D2 smaller by a predetermined amount than the outer diameter dimension D1 of the rotor core 6a, the leakage magnetic flux Φ2 generated from the coil end 5b when the permanent magnet motor is driven is linked to the high-density member 6b and an eddy current is generated. Since it does not flow, the eddy current loss of the rotor core 6a due to the stator winding 11 can be reduced, and a compressor motor capable of reducing the iron loss can be realized (that is, the problem C can be solved).
At this time, the high density member portion 6b may be made of a magnetic metal instead of a nonmagnetic metal.
Even if the outer diameter dimension relationship between the high-density member portion 6b and the rotor core portion 6a is not particularly D2 <D1, the high-density member portion 6b is made of a thin magnetic metal plate (for example, a thin brass plate) or magnetic. Even if a metal plate (for example, a thin electromagnetic steel plate) is laminated through an insulating film, the problem C can be solved.
[0023]
Further, the axial lengths of the rotor core portion 6a and the stator core portion 5a are made substantially the same in the axial direction, or the axial length of the rotor core portion 6a provided with the permanent magnet 10 having the substantially same length is set as the stator core. Since the length in the axial direction of the portion 5a is longer and the non-magnetic metal high-density member portion 6b having a diameter D2 smaller than the outer diameter D1 of the rotor core portion 6a is attached to both ends of the rotor core portion 6a, The magnetic flux generated by the current flowing through the winding 11 of the stator 5 does not generate or reduces the leakage magnetic path of the path passing through the outer peripheral end in the axial direction of the rotor core 6a (that is, the copper loss can be reduced). Problem B can be solved).
At this time, the high density member portion 6b may be made of a magnetic metal instead of a nonmagnetic metal.
[0024]
Further, by forming the high-density member portion 6b in the same manner as the rotor core portion 6a, that is, by forming a thin magnetic metal plate in the same progressive die as the rotor core portion 6a. The manufacturing process can be simplified, and the manufacturing becomes easy.
[0025]
As described above, according to the permanent magnet type motor of the present embodiment, the high-density member portion 6b made of a high-density member is provided at the axial end of the rotor core portion 6a, and the outer diameter of the high-density member portion 6b. Since the dimensions are smaller than the outer diameter of the rotor core 6a, the inertial force of the rotor 6 can be increased, the eddy current loss of the rotor core 6a can be reduced, the iron loss can be reduced, and the motor efficiency Improvement and suppression of vibration and noise.
[0026]
In addition, since the nonmagnetic metal high-density member 6b is provided at the axial end of the rotor core 6a, the inertial force of the rotor 6 can be increased, and the rotor core 6a flows inside the rotor core 6a. Leakage flux Φ1 is not generated, copper loss can be reduced, motor efficiency can be improved, and vibration and noise can be suppressed.
[0027]
Further, since the high-density member portion 6b made of the high-density member or the high-density member portion 6b made of magnetic metal is formed by laminating thin magnetic metal plates, the manufacturing process of the rotor 6 can be simplified. Manufacturing becomes easy.
[0028]
Further, since the high-density member portion 6b is formed by laminating thin metal plates via an insulating film, the inertial force of the rotor 6 can be increased, and eddy current loss of the rotor core portion 6a can be achieved. Can be reduced, iron loss can be reduced, motor efficiency can be improved, and vibration and noise can be suppressed.
[0029]
Further, by using this permanent magnet type motor for the compressor, noise generated through the hermetic container 7, the discharge pipe 25, and the suction pipe 26 can be suppressed, and the noise as a unit such as an air conditioner or a refrigerator can be reduced. It is possible. That is, it becomes a highly efficient compressor which can suppress vibration and noise. Furthermore, by forming the high-density member portion 6b of the rotor 6 of the permanent magnet motor as a laminated body, the permanent magnet motor can be easily manufactured and the cost of the compressor can be reduced.
[0030]
Embodiment 2. FIG.
FIG. 6 is a longitudinal sectional view of a compressor incorporating a permanent magnet type motor for driving a compressor according to Embodiment 2 of the present invention. FIGS. 7 and 8 are respectively a rotor of a permanent magnet type motor. FIG. 9 and FIG. 10 are respectively a cross-sectional view of another rotor core portion and a cross-sectional view of the high-density member portion of the permanent magnet motor, respectively. FIG.
In the present embodiment, the material of the high density member 6b provided at the end of the rotor core 6a of the rotor 6 is made of a metal magnetic material, and the outer dimension D3 of the high density member 6b is set to the rotor core. The outer diameter D4 of the magnet insertion hole 9 provided in 6a is set to be equal to or smaller than D4. Furthermore, the high density member portion 6b provided at the end of the rotor core portion 6a is formed by laminating thin magnetic steel sheets of about 0.3 to 0.5 mm each having an insulating film on at least one surface.
[0031]
The high density member portion 6b may be attached to either one of the upper end and the lower end of the rotor core portion 6a, or may be attached to either end, and the axial lengths of the rotor core portion 6a and the stator core portion 5a. Other configurations including the point that the axial length of the rotor core portion 6a in which the permanent magnets 10 having substantially the same length or substantially the same length are provided is longer than the axial length of the stator core portion 5a. Since this is the same as that of the first embodiment, the difference will be mainly described below.
[0032]
In the example of the rotor core portion 6a and the high-density member portion 6b of the rotor 6 shown in FIGS. 7 and 8, permanent magnet insertion arranged in a hexagonal shape on the cross section of the rotor core portion 6a orthogonal to the axial direction of the drive shaft 13 A rare earth magnet 10, which is a flat permanent magnet 10, is inserted into the hole 9. Further, on the cross section of the rotor core portion 6a orthogonal to the axial direction of the drive shaft 13 (axis orthogonal surface of the rotor core portion 6a), the outer dimension of the opposing permanent magnet insertion hole 9 is D4, and the axial direction of the drive shaft 13 When the outer dimension of the high-density member portion 6b corresponding to the axial direction in the cross section of the high-density member portion 6b orthogonal to the axis (the axis orthogonal surface of the high-density member portion 6b) is D3, the relationship between D3 and D4 corresponding in the axial direction Is D3 ≦ D4. That is, the outer dimension D3 of the high-density member portion 6b in the axis-orthogonal cross section is set to be equal to or smaller than the outer dimension D4 corresponding to the axial direction of the axis-orthogonal section of the permanent magnet insertion hole 9.
[0033]
As another example, as shown in FIG. 9, when 12 permanent magnets 10 are arranged in a V shape in the axial orthogonal cross section of the rotor core portion 6 a, the axial orthogonal cross section of the high density member portion 6 b is Similarly, the relationship between D3 and D4 is set as D3 ≦ D4, and the external dimension D3 of the high-density member portion 6b is perpendicular to the axial direction of the permanent magnet insertion hole 9. D4 or less.
[0034]
As described above, according to the permanent magnet type motor of the present embodiment, the high-density member 6b made of magnetic metal is provided at the axial end of the rotor core 6, and the high-density member 6b and the rotor core When the outer dimensions corresponding to the axial direction of the magnet insertion hole 9 of 6a and the respective axial cross sections are D3 and D4, D3 ≦ D4. A compressor motor with vibration and low noise can be realized, and from the relationship of D3 ≦ D4, a decrease in effective magnetic flux due to magnetic path formation of the permanent magnet 10 can be prevented, and copper loss can be reduced (resolving problem A).
[0035]
Further, the high-density member portion 6b realizes low vibration and low noise, and the high-density member portion 6b is formed by laminating a thin magnetic metal plate with an insulating film interposed therebetween. The eddy current loss of the iron core portion 6a can be reduced, and a compressor motor that can reduce the iron loss can be realized (solvent C).
In addition, even if a magnetic metal plate is a non-magnetic metal plate, it is effective in solving the problem C.
[0036]
Further, the configuration of the high-density member portion 6b is configured to be slightly smaller than the outer diameter dimension D4 of the magnet insertion hole 9 and larger than the inner diameter dimension of the magnet insertion hole 9, thereby holding the permanent magnet 10 in the axial direction. Can be made easier.
[0037]
Further, since the high-density member portion 6b is also composed of a laminated core (laminate of thin magnetic metal plates) in the same manner as the rotor core portion 6a, the high-density member in the same progressive die as the rotor core portion 6a. The part 6b can be manufactured, and a low-cost permanent magnet type motor with a reduced manufacturing process can be provided.
[0038]
Further, by using this permanent magnet type motor, a low noise and high efficiency compressor can be realized. Furthermore, by forming the high-density member portion 6b of the rotor 6 of the permanent magnet motor as a laminated body, the permanent magnet motor can be easily manufactured and the cost of the compressor can be reduced.
[0039]
In the first and second embodiments, the permanent magnet type motor increases the inertial force of the rotor 6 by providing the high-density member portion 6b made of a high-density material at the end of the rotor core portion 6a. The efficiency can be improved by providing a characteristic configuration that reduces noise and solves the problems A, B, and C at the same time, but the configuration that eliminates these problems A, B, and C is efficient by providing at least one configuration. Further improvement of efficiency can be achieved by providing more than one.
Moreover, by using such a permanent magnet type motor for the compressor, it is possible to obtain a highly efficient compressor that reduces vibration and noise and at the same time eliminates at least one of the problems A, B, and C. .
[0040]
【The invention's effect】
As described above, in the present invention, the permanent magnet type motor is provided with a high-density member made of magnetic metal at the axial end of the rotor core portion, and the high-density member and the magnet insertion hole of the rotor core portion, When the external dimensions corresponding to the axial direction in the orthogonal cross section are D3 and D4, since D3 ≦ D4, a low-vibration and low-noise compressor motor can be realized, and the effective magnetic flux generated by the magnetic path formation of the permanent magnet can be realized. Reduction can be prevented and copper loss can be reduced.
In addition, by using this permanent magnet type motor, the speed fluctuation of the rotor due to the pressure fluctuation generated during the suction, compression, and discharge processes of the compression mechanism can be mitigated, and vibration can be reduced. Noise generated through the discharge pipe and suction pipe can be suppressed, and a highly efficient compressor with reduced vibration and noise can be obtained.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a longitudinal sectional view of a compressor incorporating a permanent magnet motor for driving a compressor according to Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view of the rotor of FIG.
FIG. 3 is a simplified diagram showing a compressor mechanism of the compressor of FIG. 1;
FIG. 4 is a conceptual diagram showing pressure fluctuations in the compressor.
FIG. 5 is a diagram showing a current waveform waveform of a permanent magnet type motor.
6 is a longitudinal sectional view of a compressor incorporating a permanent magnet motor for driving a compressor according to Embodiment 2 of the present invention. FIG.
7 is a cross-sectional view of a rotor core portion of the permanent magnet type motor of FIG.
8 is a cross-sectional view of a high-density member portion of the permanent magnet type motor of FIG.
9 is a cross-sectional view of another rotor core portion of the permanent magnet type motor of FIG. 6. FIG.
10 is a cross-sectional view of another high density member portion of the permanent magnet type motor of FIG. 6;
[Explanation of symbols]
5 Stator, 5a Stator core, 6 Rotor, 6a Rotor core, 6b High density member, 9 Magnet insertion hole, 10 Permanent magnet, 11 Winding, 13 Drive shaft.

Claims (4)

A rotor having a drive shaft, a rotor core portion into which a permanent magnet is inserted, fixed to the drive shaft passing through the center and rotating integrally, and a predetermined gap from an outer peripheral portion of the rotor core portion. In a permanent magnet type motor having a stator iron core part formed so as to surround the part, and a stator provided with a winding,
A high-density member made of magnetic metal is provided at the axial end of the rotor core, and the outer dimensions corresponding to the axial direction of the high-density member and the magnet insertion hole of the rotor core are orthogonal to each other. A permanent magnet type motor characterized by D3 ≦ D4 when D3 and D4. Claim 1 Symbol placement of a permanent magnet motor, characterized in that the dense member portion, is formed by lamination of thin metal plate thicknesses. Before SL provided a high density member unit Do that a dense member in the end portion in the axial direction of the rotor core portion, that the high-density member unit, the thin metal plate having a thickness of was formed by stacking via an insulating film The permanent magnet type motor according to claim 1 . A compressor using the permanent magnet type motor according to any one of claims 1 to 3 as a motor of the compressor.

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