(1) Field of the Invention
The present invention relates to a self-starting type axial gap synchronous motor having an axial gap type induction and synchronous motor in which rotors and a stator are oppositely arranged in the axial direction, and a compressor and a refrigeration cycle apparatus using the same.
(2) Description of the Related Art
For example, Japanese Patent Application Laid-Open No. 2009-38871 discloses a conventional axial gap motor having an axial gap type induction and synchronous motor. In the conventional technique, a PM (permanent magnet) rotor in which plural permanent magnets are arranged in the circumferential direction at even intervals and an IN rotor as an induction motor are arranged on both sides of a stator in the axial direction, the both rotors are fixed to a common rotational shaft, and air gaps are provided between the rotors and the stator, so that the rotors can be rotated.
Japanese Patent Application Laid-Open No. 2009-38871 describes the invention in which the IM rotor and the PM rotor are simultaneously driven during power running to obtain strong torque.
However, if the induction and synchronous axial gap motor described in Japanese Patent Application Laid-Open No. 2009-38871 is started by a commercial electric power, rotary torque is generated at the IM rotor because the IM rotor is used as an induction motor. However, the PM rotor functions as a brake to increase a load, and thus sufficient starting induction torque cannot be possibly obtained. Specifically, in Japanese Patent Application Laid-Open No. 2009-38871, starting of the induction and synchronous axial gap motor by a commercial electric power is not considered.
Further, in Japanese Patent Application Laid-Open No. 2009-38871, only the PM rotor provided on one side of the stator contributes to synchronous operations by a commercial electric power, and no torque is generated by the IM rotor on the other side. Thus, it is difficult to obtain high rotary torque as a whole, and it is impossible to withstand a large load.
Further, as a general stator core of a motor, electromagnetic metal plates are laminated on each other. However, in the stator core using the electromagnetic metal plates, eddy current proportional to the square of the thickness of the electromagnetic metal plate, is generated at the electromagnetic metal plates of the stator core under the influence of rotating magnetic fields generated at the time of rotation of the motor to cause a large loss. The loss is one of the factors of deteriorating the efficiency of the motor. Accordingly, it is necessary to reduce the loss (iron loss) in order to improve the efficiency of the motor.
It should be noted that in the case where the axial gap type motor is configured in such a manner that permanent magnets with different poles are arranged in rotors arranged on both end sides of a stator, cogging torque thereof is expected to be larger than that of a conventional radial gap type motor.
An object of the present invention is to obtain a self-starting type axial gap synchronous motor that can be started by a commercial electric power without using an inverter, and a compressor and a refrigeration cycle apparatus using the same.
In order to achieve the above-described object, the present invention provides a self-starting type axial gap synchronous motor including: a stator in which plural small stators are arranged on the same circumference; disc-shaped rotors in each of which plural permanent magnets facing the stator are arranged on the same circumference; and a shaft coupled to the rotors, wherein each of the disc-shaped rotors includes a metal frame that is provided so as to surround the plural permanent magnets arranged on the same circumference, and each of the metal frames is configured using a nonmagnetic and conductive material.
Further, according to another aspect of the present invention, there is provided a compressor including a compression mechanical unit and a motor that drives the compression mechanical unit, wherein the motor is configured using the self-starting type axial gap synchronous motor.
Further, according to yet another aspect of the present invention, there is provided a refrigeration cycle apparatus including a condenser and an evaporator, each having a fan driven by a motor, wherein the motor of the fan provided in at least any one of the condenser and the evaporator is configured using the self-starting type axial gap synchronous motor.
According to the present invention, it is possible to obtain a self-starting type axial gap synchronous motor that can be started by a commercial electric power without using an inverter, and a compressor and a refrigeration cycle apparatus using the same.
Hereinafter, embodiments of the present invention will be described on the basis of the drawings.
A self-starting type axial gap synchronous motor according to a first embodiment of the present invention will be described using
As shown in
The rotors 3 are oppositely arranged on both end sides of the stator 2 so as to sandwich the stator 2, and are fixed to the shaft 4. Plural permanent magnets 17 are arranged on the same circumference of each rotor 3 at even intervals, and are provided at positions facing the plural small stators 16. Further, each of the rotors 3 is fixed to the shaft 4 while having a certain gap (smaller than 2 mm) with respect to each of both end surfaces of the stator 2, and can be freely rotated together with the shaft 4.
It should be noted that the small stators 16 are configured using small stator cores 14 and coils 15 wound around the small stator cores 14, and a nonmagnetic member 11 is provided in the middle of each small stator core 14. Further, the rotors 3 include nonmagnetic disks 9 and metal frames 6 fixed to the disks 9, and the respective permanent magnets 17 are surrounded by the metal frames 6. Further, the metal frames 6 and the permanent magnets 17 are fixed to the disks 9 through insulating papers 31.
As shown in
In the embodiment, the diameter of the metal frame 6 is substantially equal to that of the disk 9, the material thereof is aluminum (including aluminum alloy) or copper (including copper alloy), and is produced by a method such as aluminum die-casting or forging.
Plural holes 6a in which the permanent magnets 17 are arranged are provided at the metal frame 6 in the circumferential direction at even intervals. The permanent magnets 17 are arranged in the respective holes 6a provided at even intervals, and are fixed to the disk 9 using an adhesive or the like. The outer circumference of each of the permanent magnets 17 may be brought into contact with the metal frame 6. Alternatively, a space may be provided so as not to allow the outer circumference of each of the permanent magnets 17 to be brought into contact with the metal frame 6.
After assembling the rotor 3, the permanent magnets 17 are magnetized to serve as permanent magnets by supplying pulse current using a magnetization device. Further, as shown in
An axial gap between the stator 2 and each rotor 3 after being assembled as a motor is set at 2 mm or smaller to avoid contact, and may be uniform or non-uniform. It should be noted that each axial gap is preferably as small as possible to avoid contact. In general, each axial gap is preferably set at 0.3 to 1.5 mm, and more preferably 0.4 to 0.8 mm.
A configuration of the metal frame 6 that is provided so as to surround the plural permanent magnets arranged on the same circumference will be described using
A configuration of each of the plural small stators 16 that configure the stator 2 and are arranged in the circumferential direction will be described using
As shown in
The nonmagnetic member 11 has a substantially fan-shaped cross-section with a certain length as shown in
As shown in
Next, a structure of the stator 2 shown in
In the embodiment, the motor is configured using a 12-pole stator and 8-pole rotors. However, a different combination may be employed as the pole ratio between the stator and the rotors.
Further, the rotors 3 and the stator 2 may be inversely arranged so as to arrange the rotors in the middle, and the stators may be arranged on the both end sides of the rotors.
Next, the reason that the rotary torque is generated to drive the self-starting type axial gap synchronous motor as described above will be described using, especially,
When current is applied to the three-phase coils 15 of the stator 2 by a commercial electric power, rotating magnetic fields H are generated by the coils 15 as shown in
According to the above-described embodiment, it is possible to obtain a motor that can be operated at a constant speed by a commercial electric power without inverter control, and circuits for inverter control are not needed, resulting in cost reduction.
Further, the stator 2 is produced in such a manner that each of the small stator cores 14 is produced by winding the amorphous ribbon with low iron loss and high magnetic permeability in a roll shape, the coil 15 is wound around each of the small stator cores 14 to produce the small stator 16, and the small stators 16 are arranged in the circumferential direction. Thus, not only the stator 2 can be produced by simple production steps, but also a high-efficiency self-starting type axial gap synchronous motor with less iron loss can be realized.
Thus, according to the embodiment, it is possible to obtain a high-efficiency and high power-factor self-starting type axial gap synchronous motor that can be operated at a constant speed by a commercial electric power without using an inverter.
Next, a second embodiment of the present invention will be described using
A small stator core 24 shown in
When operating the motor, reflux-like eddy current is generated at the lamination plane of the small stator core 24 under the influence of the rotating magnetic fields to cause a loss. The loss caused by the eddy current is one of the factors of lowering the efficiency of the motor. In order to reduce the loss caused by the eddy current, a slit 25 having a width of 2 mm or smaller is provided at the lamination plane of each small stator core 24 in the axial direction so as to cut the amorphous ribbon 22 in the embodiment. The slit 25 is formed in the middle of a plane portion of the amorphous ribbon 22 in the axial direction as shown in
By providing the slit 25, a loop where the eddy current is formed can be opened, and it is possible to prevent the eddy current from being formed on the lamination plane of each small stator core 24. Thus, it is possible to obtain a self-starting type axial gap synchronous motor that can further improve efficiency by reducing the loss as compared to that in the first embodiment.
It should be noted that the slit 25 is not limited to the slit penetrating the amorphous ribbon 22 in the axial direction as shown in
A small stator 30 is formed in such a manner that as shown in
According to the embodiment, the same effects as those in the first embodiment can be obtained, the loss of the stator configured using the amorphous core material with a low loss can be further reduced, and thus the efficiency of the self-starting type axial gap motor can be further improved.
A third embodiment of the present invention will be described using
The small stator cores 34 and 38 shown in
When the motor shown in
In the first example shown in
Next, the second example shown in
With such a configuration, induction voltage induced by the coil 15 wound around the small stator core 38 is smoothly changed in the circumferential direction of the small stator core 38 when the motor is rotated. Thus, the amplitude of the cogging torque generated between the stator 2 and the adjacent permanent magnets 17 with different poles (S and N poles) is reduced by the induction voltage that is smoothly changed in the circumferential direction. As a result, it is possible to obtain a self-starting type axial gap synchronous motor in which vibration and noise can be suppressed.
According to the embodiment, the same effects as those in the first embodiment can be obtained, and the noise and vibration of the high-efficiency self-starting type axial gap synchronous motor configured using the amorphous core material with a low loss can be advantageously reduced.
In the fourth embodiment, the thickness of each permanent magnet 47 provided in the metal frame 6 of the rotor 3 is changed. For example, the surface of a middle portion of each permanent magnet 47 may be formed in a convex hemisphere shape, or the surface of each permanent magnet 47 may be formed in a curved shape in which the both end portions in the circumferential direction are thinner than the middle portion in the circumferential direction.
With such a configuration, gaps between the small stator cores 14 and the permanent magnets 47 facing the small stator cores 14 are changed in the circumferential direction, and thus the pulsation of the rotary torque applied to the permanent magnets 47 can be reduced. Accordingly, as similar to the third embodiment, it is possible to obtain a self-starting type axial gap synchronous motor in which the amplitude of the cogging torque generated between the permanent magnets 47 and the small stator cores 14 can be reduced, and vibration and noise can be suppressed.
As shown in
The compression mechanical unit 83 is configured by meshing a fixed scroll obtained by erecting a rolled scroll wrap 62 on an end plate 61 with a pivoting scroll obtained by erecting a rolled scroll wrap 65 on an end plate 64. The pivoting scroll 63 is pivoted by a crankshaft 4a, so that compression operations are performed.
Among plural compression chambers 66 formed by the fixed scroll 60 and the pivoting scroll 63, the compression chamber that is positioned at the outermost part in the radial direction is moved toward the centers of the both scrolls 60 and 63 along with the pivoting movement of the pivoting scroll 63 and the volume thereof is gradually decreased. In addition, the compressed refrigerant gas is discharged to a discharging chamber 74 from a discharging port 67 provided near a middle portion of the fixed scroll 60. The discharged compressed-gas flows into the pressure vessel 69 under a frame 68 through gas channels (not shown) provided on the outer circumferential side of the fixed scroll 60 and the frame 68, and oil contained in the compressed gas is separated. As a result, the oil is discharged to the outside of the compressor from a discharging pipe 70 provided at a side wall of the pressure vessel 69. It should be noted that the reference numeral 75 denotes a back pressure chamber whose pressure is maintained at an intermediate pressure between a discharging pressure and a sucking pressure; 76, a secondary bearing; and 80, a balance weight.
As the motor 1, the self-starting type axial gap synchronous motor that is described in each embodiment with reference to
According to the embodiment, since the self-starting type axial gap synchronous motor that is described in each embodiment with reference to
It should be noted that if the self-starting type axial gap motor described in the third embodiment is employed, excessively-high starting torque generated due to power-on phases can be reduced. Thus, it is possible to obtain a highly-reliable scroll compressor in which stress destruction of the bearing 73 and the pivoting scroll 63 can be prevented.
It should be noted that the self-starting type axial gap motor in each of the first to fourth embodiments can be similarly applied to not only the scroll compressor, but also a rotary or reciprocating compressor.
A fan 88 and a motor for driving the fan 88 are provided in each of the condenser 84 and the evaporator 86, and as the motors, the self-starting type axial gap synchronous motors 1 described in each of the first to fourth embodiments are used. When the motors 1 are rotated, the fans 88 are also rotated, so that heat exchange between refrigerant flowing in heat exchangers of the condenser 84 and the evaporator 86 and ambient air is carried out.
In the refrigeration cycle shown in
In the embodiment, the self-starting type axial gap synchronous motors 1 described in each of the first to fourth embodiments are used for the fans 88 of the evaporator and the condenser configuring the refrigeration cycle. Thus, the efficiency of the fans can be improved without using an inverter, and emissions of CO2 leading to global warming can be advantageously reduced by decreasing inputs. Further, the use of the self-starting type axial gap synchronous motors 1 described in the third or fourth embodiment leads to improvement in reliability of the fans.
It should be noted that the fans 88 are preferably propeller fans or turbo fans. Further, there has been described a case in the embodiment that the refrigeration cycle apparatus is used for an air conditioner. However, the refrigeration cycle apparatus can be similarly used for a refrigerator and a freezer.
As described above, according to each embodiment of the present invention, it is possible to obtain a self-starting type axial gap synchronous motor that can be started by a commercial electric power without using an inverter, and a compressor and an air conditioner using the same.
Further, in the self-starting type axial gap synchronous motor, the rotors provided on the both sides of the stator contribute to synchronous operations to generate the rotary torque even in synchronous operations by a commercial electric power. Accordingly, high rotary torque can be obtained as a whole. Thus, it is possible to obtain a self-starting type axial gap synchronous motor that can withstand a large load.
In the structure of the stator core of the motor in which the amorphous ribbon is wound around the nonmagnetic member, the eddy current generated at the stator core can be considerably reduced under the influence of the rotating magnetic fields at the time of rotation of the motor, and thus the efficiency of the motor can be improved while reducing a loss. Further, according to each embodiment, punching work for an amorphous core material is not necessary, and thus a die for the punching work is not needed, resulting in cost reduction and reduction in the number of manufacturing steps.
Further, in the self-starting type axial gap synchronous motor of the embodiment, the rotors are provided on the both end sides of the stator, and the permanent magnets with different poles are arranged. Thus, not only the output can be increased, but also opposing magnetic force is generated in the axial direction. Accordingly, a low-vibration motor can be obtained. Further, it is possible to minimize the cogging torque by employing the configuration described in the third or fourth embodiment.
Number | Date | Country | Kind |
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2010-263432 | Nov 2010 | JP | national |