JP3636019B2 - Method for demagnetizing and crushing permanent magnet motor and method for disassembling a product having a permanent magnet motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a permanent magnet demagnetization method and a crushing method when recycling a permanent magnet motor.
[0002]
[Prior art]
Conventionally, without demagnetizing the permanent magnet used in the permanent magnet type motor, the motor is crushed using a crusher while maintaining the magnetic force of the permanent magnet, and then the material is separated.
[0003]
Further, as a demagnetization method for a permanent magnet motor, it has been known to demagnetize the permanent magnet by raising the temperature of the motor to a temperature equal to or higher than the Curie temperature of the permanent magnet (a temperature at which the permanent magnet loses its magnetic force).
[0004]
[Problems to be solved by the invention]
In the method of crushing, selecting and recycling electrical products using permanent magnet motors, the permanent magnet is placed in each place of equipment composed of magnetic material. Adhered and had an adverse effect. In particular, the iron scraps and the blades of the crusher adhere to the crusher during crushing, causing problems such as iron scraps and magnets not coming out of the crusher, causing a reduction in crushing capacity of the crusher and blade deterioration. In addition, even when the material comes out of the crusher and sorts the material, the magnet pieces adhering to the iron scrap are collected in the same place as the iron scrap, which causes a problem that the quality of the iron is lowered.
In the method of demagnetizing the permanent magnet by raising the motor temperature to about 400 ° C. or more of the permanent magnet Curie temperature before crushing the motor, a large furnace or the like is used to raise the motor temperature. The need for equipment and a lot of energy required an increase in recycling costs.
Also, in the case where a permanent magnet type motor such as a compressor is incorporated and commercialized, there may be a temperature constraint condition on parts other than the motor, and it is not always necessary to raise the Curie temperature for each product during recycling. There was a problem that it was not always acceptable.
[0005]
The present invention has been made to solve the above-mentioned problems. The permanent magnet used in the permanent magnet motor is demagnetized only with simple equipment, and a magnet piece is placed on the blade or magnetic part of the crusher during recycling. The purpose is to prevent adhesion.
[0006]
[Means for Solving the Problems]
A demagnetizing method for a permanent magnet motor according to the present invention includes a step of placing the motor under a predetermined temperature condition, and a step of applying an alternating current that decays with time between predetermined terminals of the stator armature winding. The predetermined temperature was set to be equal to or lower than the melting temperature of the winding film.
[0007]
The method for crushing a permanent magnet motor according to the present invention includes a step of demagnetizing a permanent magnet provided in the permanent magnet motor using the demagnetization method of the permanent magnet motor, and the demagnetized motor. And crushing with a crusher.
[0008]
Further, a disassembly processing method for a product including a permanent magnet type motor according to the present invention is the above-described disassembly processing method for a product including a component on which a permanent magnet type motor is mounted and which is affected by a magnetic field by the permanent magnet. The demagnetizing method of the permanent magnet motor or the crushing method of the permanent magnet motor described above was applied.
[0009]
Further, in a method for disassembling a product having a permanent magnet motor mounted thereon and including a component that is affected by a magnetic field by the permanent magnet, the motor is set to a predetermined temperature condition equal to or lower than an allowable temperature when the product is used. And a step of applying an alternating current that decays with time between predetermined terminals of the stator armature winding, wherein the product is a compressor, and the predetermined temperature condition is equal to or lower than an allowable refrigerant temperature of the compressor. .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a sectional view showing a structure of a general three-phase four-pole permanent magnet motor. In the figure, reference numeral 1 denotes a cylindrical stator core provided with a plurality of slots 2a, 2b,... 2f extending in the axial direction on the inner peripheral surface, and between the adjacent slots 2a, 2b,. 3b... 3f are formed. Reference numeral 4 denotes a coil directly wound around the teeth 3a, 3b,... 3f. FIG. 2 is a connection diagram of the coil as viewed from the inner diameter side of the motor. As shown in this figure, the coil is composed of three phases of the U phase, the V phase, and the W phase. Concentrated windings are applied so that Reference numeral 5 denotes a stator having a stator core 1 and a coil 4.
[0011]
6 is a rotor shaft which is arranged on the axis of the stator 5 and is rotatable with respect to the stator 5, 7 is a rotor core fixed to the rotor shaft 6, and 8 is a plurality of permanent magnets fixed to the outer peripheral surface of the rotor core 7. These permanent magnets 8 are mainly composed of ferrite or neodymium, and are magnetized so that N poles and S poles are alternated. Reference numeral 9 denotes a rotor having a rotor shaft 6, a rotor core 7, and a permanent magnet 8, and a gap 10 is provided between the rotor 9 and the stator 5.
[0012]
Next, a method for demagnetizing a permanent magnet using a stator of a permanent magnet motor will be described with reference to FIGS. 3, 4, and 5. For example, as shown in FIG. 3, the stator 5 is fixed to the casing 13 of the compressor 12 used in a room air conditioner, a refrigerator, or the like by shrink fitting. The terminal of the stator coil is connected to a glass terminal 14 attached to the upper part of the compressor, enabling energization of the stator coil. Further, the rotor 9 and the rotor shaft 6 are integrated by being fixed by shrink fitting, and the rotor shaft is held by the bearing portion 15.
[0013]
When used as a refrigeration cycle, refrigerant such as HFC or HCFC flows through the compressor 12, and an allowable temperature (eg, 130 ° C.) due to the refrigerant temperature or refrigerant discharge temperature, refrigeration oil such as mineral oil, HAB oil, or ester oil. There exists an allowable temperature (for example, 100 ° C.) for preventing the deterioration of the material. Further, the coating covering the motor coil may have an allowable temperature of about 130 ° C. depending on the allowable temperature of the compressor. Furthermore, the resin portion of the motor has a relatively low allowable temperature. These allowable temperatures are considerably lower than the Curie temperature of a permanent magnet of a permanent magnet type motor usually used for driving a compressor. FIG. 4 is a connection diagram when a current is applied to a three-phase Y-connected motor to demagnetize, and FIG. 5 shows a current waveform at that time.
[0014]
In order to demagnetize the permanent magnet of the permanent magnet motor provided in the compressor, first, a U-phase terminal is connected to one end of a single-phase power source 11 provided outside, and a V-phase terminal and a W-phase terminal are connected. Connect the terminal to the other terminal of the AC power supply 11. Next, an alternating current having an initial value of about 1 kA and decaying with time is applied to each terminal of the motor using the power source 11 as shown in FIG. As a result, an alternating magnetic field with a gradually decreasing amplitude is applied to the permanent magnet, so that the direction of the magnetic moment in the permanent magnet is averaged, the residual magnetism due to the hysteresis phenomenon is gradually reduced, and the strength of the alternating magnetic field is increased. The permanent magnet 8 can be demagnetized in a state in which has reached zero. After demagnetizing the permanent magnet in this way, the motor is crushed in a state where it is incorporated in the compressor.
[0015]
As described above, by applying a decaying alternating current between predetermined terminals of the stator coil, the demagnetization of the permanent magnet can be achieved with only a simple power supply without removing the motor from the compressor housing. Can be easily performed. Further, since a large amount of energy such as raising the temperature of the permanent magnet to the Curie point or higher is not required, energy saving and cost reduction of recycling can be achieved. Moreover, deterioration of the crusher due to the magnet pieces adhering to the blade or magnetic part of the crusher can be prevented.
[0016]
In this embodiment, a 6-slot and 4-pole concentrated winding motor has been described as an example. However, the combination of the number of slots and the number of poles can be applied to all motors as long as the motor can rotate. is there. Further, in the present embodiment, the concentrated winding in which the winding is wound directly on the teeth has been described as an example, but the same effect can be obtained even if a distributed winding is used instead of the concentrated winding.
[0017]
Further, in the present embodiment, the compressor motor used in the room air conditioner and the refrigerator has been described as an example. However, for example, the compressor driving motor, the washing machine driving motor, the fan motor, and the cleaner of the dehumidifier Needless to say, the present invention is applicable to all products on which a permanent magnet type motor is mounted, such as a motor for driving an FDD or an electric vehicle.
[0018]
Embodiment 2. FIG.
FIG. 6 is a flowchart showing a demagnetizing method for the permanent magnet motor according to the second embodiment of the present invention. In the first embodiment of the invention, the temperature condition is not defined for performing the demagnetization work of the permanent magnet, whereas in the second embodiment, the temperature condition at the time of the demagnetization work is defined. This is different from the first embodiment. That is, the process includes a process of setting the motor under a predetermined temperature condition (step S11) and a process of applying an attenuation current to the motor under the predetermined temperature condition (step S12).
[0019]
FIG. 7 shows a demagnetization curve of the ferrite magnet. FIG. 8 shows a demagnetization curve of a rare earth magnet composed mainly of neodymium, iron, boron or the like. The horizontal axis indicates the holding force, and the smaller the holding force, the more demagnetizing the permanent magnet can be performed with a small demagnetizing field (small current). The vertical axis represents the residual magnetic flux density, and the larger the residual magnetic flux density, the greater the magnetic force of the magnet. From this figure, it can be seen that the ferrite magnet has a characteristic that the holding force becomes smaller as the temperature becomes lower. In contrast, the rare earth magnet has a characteristic that the holding force decreases as the temperature increases. Therefore, the demagnetization characteristics of the permanent magnet vary depending on the material constituting the permanent magnet. When the material of the permanent magnet is composed mainly of ferrite, the motor temperature is set to a temperature lower than room temperature. If the material is composed mainly of neodymium, iron, boron, etc., the motor temperature is set to a temperature higher than room temperature, and then the damping current is applied so that the Curie point is exceeded. Without increasing the temperature of the permanent magnet, highly reliable demagnetization can be performed with less power than at normal temperature.
[0020]
As an example, a temperature condition in the case of a motor using a ferrite magnet is about −20 ° C. As a temperature condition in the case where neodymium, iron, boron, or the like is used as a main component, about 100 ° C. can be mentioned. The condition of 100 ° C. is within the allowable temperature of the compressor described above, and other parts are not deformed, and subsequent disassembly and crushing processing can be performed smoothly.
[0021]
Embodiment 3 FIG.
By making the allowable temperature of each component constituting the compressor 12 in FIG. 3 higher than the Curie temperature of the permanent magnet, the compressor is placed under the Curie temperature to demagnetize, and then the same as in the first and second embodiments. The compressor may be crushed. In particular, when using a refrigerant having a high compressor discharge temperature such as R21 when the Curie temperature of the permanent magnet is low and the compressor is used as a refrigeration cycle, the allowable temperature of the compressor should be designed high. Therefore, there may be a case where the compressor can withstand the Curie temperature without incurring much cost to withstand the Curie temperature. In such a case, the permanent magnet can be demagnetized by making the compressor a product having an allowable temperature equal to or higher than the Curie temperature.
[0022]
In each of the above embodiments, the case of demagnetization has been described as an example.
[0023]
【The invention's effect】
As described above, according to the present invention, since it includes a step of applying an alternating current that decays with time between predetermined terminals of the stator armature winding, without increasing the temperature of the permanent magnet to the Curie point or higher, An effect is obtained that the demagnetization of the permanent magnet can be easily performed with simple equipment.
[0024]
In addition, since the method includes a step of putting the motor under a predetermined temperature condition and a step of applying an alternating current that decays with time between predetermined terminals of the stator armature winding, an effect of easily demagnetizing with a small current Is obtained.
[0025]
Further, since the predetermined temperature is set to be equal to or lower than the melting temperature of the winding film of the motor, an effect of preventing the motor from being deteriorated can be obtained.
[0026]
In addition, since it includes a step of demagnetizing the permanent magnet provided in the permanent magnet type motor using any one of the demagnetization methods described above, and a step of crushing the demagnetized motor using a crusher, The effect which can prevent that the crushed magnet piece adheres to iron scrap and the magnetic part of a crusher is acquired.
[0027]
Further, in a dismantling method of a product equipped with a permanent magnet motor and having a part affected by a magnetic field by the permanent magnet, the demagnetizing method for the permanent magnet motor or the crushing method for the permanent magnet motor described above. As a result, it is possible to easily recycle the permanent magnet motor.
[0028]
Further, in a method for disassembling a product having a permanent magnet motor mounted thereon and including a component that is affected by a magnetic field by the permanent magnet, the motor is set to a predetermined temperature condition equal to or lower than an allowable temperature when the product is used. And a step of applying an alternating current that decays with time between predetermined terminals of the stator armature winding, so that demagnetization can be performed while preventing deformation and deterioration of the product, and subsequent disassembly processing Can be obtained smoothly.
[0029]
In addition, since the product is a compressor and the predetermined temperature condition is equal to or lower than the allowable refrigerant temperature of the compressor, it is possible to easily demagnetize with a small current while preventing an increase in the cost of the compressor.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the structure of a three-phase four-pole permanent magnet motor according to the present invention.
FIG. 2 is a connection diagram of coils of the permanent magnet type motor of FIG.
FIG. 3 is a cross-sectional view of a compressor including the permanent magnet type motor of FIG.
FIG. 4 is a connection diagram when a motor is demagnetized.
FIG. 5 is a waveform diagram showing a current waveform at the time of demagnetization.
FIG. 6 is a flowchart showing a demagnetizing method for a permanent magnet type motor according to Embodiment 2 of the present invention;
FIG. 7 is a demagnetization curve showing the characteristics of a ferrite magnet.
FIG. 8 is a demagnetization curve showing characteristics of a rare earth magnet.
[Explanation of symbols]
1 Stator core, 2a, 2b... 2f slot, 3a, 3b. Case, 14 glass terminal, 15 bearing, 16 U-phase terminal, 17 V-phase terminal, 18 W-phase terminal.

Claims (4)

Including a step of placing the motor under a predetermined temperature condition and a step of applying an alternating current that decays with time between predetermined terminals of the stator armature winding, the predetermined temperature being equal to or lower than a melting temperature of the winding film of the motor and then magnetizing method reduced the permanent magnet motor, characterized in that the. The method of demagnetizing the permanent magnet provided in the permanent magnet type motor using the demagnetizing method according to claim 1 and the step of crushing the demagnetized motor with a crusher. Crushing method for permanent magnet motor. Is a permanent magnet motor is mounted, wherein the disassembly processing method of a product having a component affected by the magnetic field by the permanent magnets, reducing magnetizing method of the permanent magnet type motor according to claim 1 or claim 2 permanent magnet type motor according A method for disassembling a product provided with a permanent magnet motor, characterized by applying the crushing method. In a method for disassembling a product equipped with a permanent magnet type motor and including a part affected by a magnetic field by the permanent magnet, the step of setting the motor to a predetermined temperature condition that is equal to or lower than an allowable temperature during use of the product; Applying an alternating current that decays with time between predetermined terminals of the stator armature winding , wherein the product is a compressor, and the predetermined temperature condition is equal to or lower than an allowable refrigerant temperature of the compressor. A dismantling method for a product provided with the featured permanent magnet motor.

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