JPH11252874A - Method and member for magnetization in permanent magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce stator defect due to magnetization, by performing magnetization with a magnet fitted into a rotor assembled into a casing, and utilizing a member for magnetization placed outside the casing. SOLUTION: A stator 3 and a rotor 6 are assembled into a compressor casing 1. The stator 3 has 24 slots 3a formed on its inner circumference. Stator winding 4 is installed in the slots 3a. Four magnets 7 are fitted into the rotor 6. The magnets 7 are rare-earth magnets, for example. An annular yoke 2 for magnetization (member for magnetization) is placed outside the compressor casing 1. The external yoke 2 for magnetization is made of magnetic material, for example, and has four slots 2a. External yoke winding 5 is installed in the slots 2a. Teeth 2b are formed on both sides of the slots 2a, and the external yoke winding 5 is wound around the teeth 2b on the external yoke 2 for magnetization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetizing method and a magnetizing member for a permanent magnet type electric motor.

[0002]

2. Description of the Related Art Conventionally, a permanent magnet motor having a stator (stator) and a rotor (rotor) rotatably disposed in the stator and having a permanent magnet is widely known. This permanent magnet type electric motor is used, for example, as an electric motor of a compressor for an air conditioner.

[0003] When the rotor in the above-described permanent magnet type electric motor is mounted in the stator, if the permanent magnet of the rotor is magnetized, the rotor is attracted to the inner peripheral surface of the stator, and the rotor may be mounted in the stator. It will be difficult.

[0004] For this reason, the rotor is mounted in the stator with the unmagnetized magnet fitted to the rotor, and then a magnetizing voltage is applied to the stator winding to magnetize the magnet.

[0005]

However, in order to energize and magnetize the stator winding, a large current of several hundreds to several thousand A needs to flow through the stator winding. for that reason,
The stator winding is deformed by receiving a very large electromagnetic force according to Fleming's left-hand rule. As a result, there is a problem that insulation failure, deviation of winding end dimensions, and the like occur, resulting in stator failure.

[0006] The present invention has been made to solve the above problems. An object of the present invention is to reduce stator defects due to magnetization.

[0007]

According to a first aspect of the present invention, there is provided a magnetizing method for a permanent magnet type electric motor in which a magnet fitted to a rotor is incorporated in a casing and the magnet is disposed outside the casing. It is characterized in that it is magnetized using a member for use.

[0008] By magnetizing the magnet fitted to the rotor using the magnetizing member arranged outside the casing as described above, the magnetized member is magnetized as compared with the conventional example not using the magnetizing member. In this case, the value of the current flowing through the stator winding can be reduced. Thereby, the electromagnetic force applied to the stator winding can be reduced, and deformation and the like of the stator winding can be suppressed.

In the magnetizing method according to the second aspect, a winding is attached to at least one of the stator and the magnetizing member of the permanent magnet type electric motor, and the magnet is magnetized by energizing the winding.

In the above configuration, for example, when current is applied only to the stator winding, the yoke width of the stator can be substantially increased because the magnetizing member is disposed outside the casing. That is, it is possible to increase the ratio of the back yoke dimensions shown in FIG. As a result, the value of the current flowing through the stator winding during magnetization can be reduced as compared with the conventional case. Further, when the magnetizing is performed by energizing only the winding of the magnetizing member, it is not necessary to energize the stator winding. Further, in the case where magnetization is performed by energizing both the stator winding and the winding of the magnetizing member, the magnetizing is performed using a composite magnetic field of the magnetic field of the magnetizing member and the magnetic field of the stator. Therefore, the value of the current flowing through the stator winding can be reduced as compared with the conventional case. Thus, in any case, the value of the current flowing through the stator winding during magnetization can be reduced as compared with the conventional case. Thereby, as described above, deformation of the stator winding and the like can be suppressed.

In the magnetizing method according to the third aspect, current is supplied only to the winding of the magnetizing member. As a result, it is not necessary to energize the stator winding as described above, and deformation and the like of the stator winding can be suppressed.

In the magnetizing method according to the fourth aspect, a plurality of magnets are fitted to the rotor and each magnet is individually magnetized.

[0013] As described above, by magnetizing the magnets individually to perform the magnetization one pole at a time, the magnetization per magnet pole can be made smaller than when a plurality of magnets are magnetized simultaneously using the same magnetizing power supply. Energy can be increased. As a result, the magnetizing power supply capacity can be reduced.

According to the magnetizing method of the present invention, the notch is provided on the outer periphery of the stator, and the slot for receiving the winding is provided on the inner periphery of the magnetizing member. Then, the coil is energized with the notch and the slot aligned.

A cutout (core cut) for passing lubricating oil or gas may be provided on the outer periphery of the stator.
The flow of the magnetic flux is hindered at the portion where the notch is provided. Therefore, by aligning the slot of the magnetizing member with the notch of the stator, magnetic flux is transferred from the teeth located between the slots of the magnetizing member to the yoke of the stator other than the portion where the notch is provided. Can be shed. Thus, it is possible to prevent the flow of the magnetic flux from being hindered by the cutout.

In the magnetizing method according to the sixth aspect, the windings are attached to both the stator and the magnetizing member, and each winding is energized.

Thus, since the magnetic field generated by both the magnetizing member and the stator can be combined and magnetized, the value of the current flowing through the stator winding can be reduced as described above.

According to the magnetizing method of the present invention, the waveform of the current flowing through the winding of the stator and the waveform of the current flowing through the winding of the magnetizing member are synchronized.

By synchronizing the waveform of the current flowing through the stator winding with the waveform of the current flowing through the winding of the magnetizing member as described above, as shown in FIG. A maximum combined magnetic field can be generated by combining the magnetic field with the magnetic field.

In the magnetizing method according to the present invention, an element for synchronizing the current waveform is connected in series with the winding of the stator.

By connecting the elements in series with the stator winding as described above, the phase of the current flowing through the stator winding can be shifted. Thereby, the waveform of the current flowing through the stator winding and the waveform of the current flowing through the winding of the magnetizing member can be synchronized. As a result, the maximum combined magnetic field as described above can be generated.

According to the ninth aspect, the winding of the stator and the winding of the magnetizing member are connected in parallel to the magnetizing power supply.

By connecting the stator winding and the magnetizing member winding in parallel to the magnetizing power supply as described above, the same voltage is applied to the stator winding and the magnetizing member winding. can do. Thereby, a desired magnetic field can be generated in both, and a larger combined magnetic field can be obtained.

According to a tenth aspect of the present invention, the magnetizing member is formed of a ring-shaped magnetic material, and only energizes the stator winding.

As described above, even when only the stator winding is energized, the yoke width of the stator can be substantially increased by the presence of the magnetizing member outside the casing. As a result, as described above, the value of the current flowing through the stator winding during magnetization can be reduced as compared with the related art.

The magnetizing member according to the eleventh aspect is arranged outside the casing to magnetize a magnet fitted to the rotor in the permanent magnet type electric motor incorporated in the casing. .

By arranging the magnetizing member outside the casing and performing magnetizing, the value of the current flowing through the stator winding can be reduced as described above.

In the twelfth aspect of the present invention, the axial thickness (thickness) of the magnetizing member is equal to or greater than the axial thickness (thickness) of the yoke of the stator of the permanent magnet motor. .

Since the magnetizing member is disposed outside the casing, a magnetic flux flows from the magnetizing member to the stator during magnetization. At this time, if the thickness of the magnetizing member is smaller than the thickness of the yoke of the stator, the magnetic flux is saturated in the magnetizing member and the loss is increased, and the effective magnetic flux is reduced. On the other hand, the loss can be reduced by setting the thickness of the magnetizing member to be equal to or greater than the thickness of the yoke of the stator, and as a result, the effective magnetic flux can be increased. This can also contribute to reducing the value of the current flowing through the stator winding.

According to a thirteenth aspect, the above-mentioned stator is provided with a first
, And first teeth provided on both sides of the first slot, and the magnetizing member has a second slot and second teeth provided on both sides of the second slot. With teeth. The sum of the tooth widths of the second teeth is equal to or greater than the sum of the tooth widths of the first teeth.

As described above, the sum of the tooth widths of the second teeth is equal to the first width.
Is greater than or equal to the sum of the tooth widths of the teeth, it is possible to increase the magnetic flux effective for magnetization, as in the case of the twelfth aspect.

In the magnetizing member according to the present invention, the magnetizing member has a slot and teeth provided on both sides of the slot. The sum of the tooth widths is equal to or greater than the outer peripheral length of the rotor.

In this case, as in the case of the twelfth and thirteenth aspects, the magnetic flux effective for magnetization can be increased, and as a result, the value of the current flowing through the stator winding can be reduced.

In the magnetizing member according to the present invention, the magnetizing member has a slot and teeth provided on both sides of the slot. The radial width (back yoke dimension) of the magnetizing member in the portion where the slot is provided is at least １ ／ of the tooth width of the teeth.

For example, as shown in FIG. 1, the magnetic flux 8 near the adjacent slot in the magnetizing member
Flow into b. Therefore, the back yoke dimension is at least １ ／ of the tooth width of the magnetizing member.
As in the case of No. 14, it is possible to increase the magnetic flux effective for magnetization. As a result, the value of the current flowing through the stator winding can be reduced.

The magnetizing member according to a sixteenth aspect is an annular magnetic body mounted on the outer periphery of the casing. The permanent magnet type electric motor has a stator, and the total width of the radial width (Lsy) of the yoke of the stator and the radial width of the magnetizing member is Lsy1, and the magnetic flux density required for magnetizing the magnet. Is Bm, the saturation magnetic flux density of the yoke of the stator and the magnetizing member is By, and the radius of the rotor is r.
The total width Lsy1 is equal to or greater than １ ／ × π × r × Bm / By.

As described above, the total width Lsy1 is 1/4 × π
When it is not less than × r × Bm / By, a magnetic flux less than the maximum magnetic flux that can be passed through the stator or the magnetizing member can be passed through the rotor to magnetize the magnet. For this reason, the magnetic material such as the stator and the magnetizing member can be used efficiently at a saturation magnetic flux density or less, and as a result, the value of the current flowing through the stator winding can be reduced as compared with the related art.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) First, Embodiment 1 of the present invention will be described with reference to FIGS. FIG.
FIG. 3 is a cross-sectional view showing a magnetizing method according to Embodiment 1 of the present invention.

Referring to FIG. 1, a stator 3 and a rotor 6 are assembled in a compressor casing 1. Twenty-four slots 3 a are provided on the inner periphery of the stator 3. The stator winding 4 is installed in the slot 3a. Four magnets 7 are fitted in the rotor 6. The magnet 7 is
For example, a rare earth magnet.

Outside the compressor casing 1, an annular outer yoke (magnetizing member) 2 is arranged. The magnetizing outer yoke 2 is made of, for example, a magnetic material and has four slots 2a. The external yoke winding 5 is installed in the slot 2a. Teeth 2b are provided on both sides of the slot 2a, and the external yoke winding 5 is wound around the teeth 2b of the magnetizing external yoke 2.

Next, the magnetizing outer yoke 2 shown in FIG.
The magnetizing method using the method will be described. As shown in FIG. 1, a current having a predetermined value is supplied to the external yoke winding 5. Thereby, the magnetic flux 8 is generated. The magnetic flux 8 passes through the magnetizing outer yoke 2 and the stator 3 and reaches the magnet 7 fitted in the rotor 6. Thereby, the magnet 7 is magnetized. At this time, the magnetic flux Φm effective for magnetizing is expressed as follows using the magnetic flux Φa leaking to the yoke of the stator 3, the magnetic flux Φb leaking in the core of the rotor 6, and the magnetic flux Φo generated by the magnetizing external yoke 2. It is.

Φm = Φo−2 × Φa−2 × Φb Next, the features of the magnetizing outer yoke 2 usable in the present invention will be described in detail with reference to FIGS. FIG. 2 shows an external yoke 2 for magnetizing outside a compressor casing 1.
FIG. 3 is a side cross-sectional view showing a state in which is installed. FIG. 3 shows FIG.
FIG. 3 is an enlarged cross-sectional view taken along the line III-III in FIG. 3, showing a cross section corresponding to the cross section shown in FIG. 1.

First, referring to FIG. 2, external magnetizing yoke 2
Is the thickness hs of the stator 3 in the axial direction.
The setting is made as described above. As shown in FIG.
Since the magnetic flux 8 flows from the magnetizing external yoke 2 to the stator 3, by setting the thickness hy of the magnetizing external yoke 2 to be equal to or greater than the thickness hs of the stator 3, a magnetic flux effective for magnetizing is obtained. Can be increased.

FIG. 4 shows the relationship between the above-mentioned thicknesses hy and hs and the magnetic flux density of the magnet. By setting the thickness to hs or more, the magnetic flux density of the magnet can be increased as a result.

Next, referring to FIGS. 3 and 5, the tooth width Lyt of the magnetizing outer yoke 2 and the tooth width Lst of the stator 3 will be described.
And the relationship with the magnetic flux density of the magnet will be described.

As shown in FIG. 5, it can be seen that the magnetic flux density of the magnet can be improved when the tooth width Lyt of the magnetizing outer yoke 2 is at least six times the tooth width Lst of the stator 3. That is, the sum of the tooth widths Lyt of the magnetizing outer yoke 2 shown in FIG.
When the sum is equal to or larger than the sum of t, the magnetic flux density of the magnet can be improved on the same principle as that for the stack thicknesses hy and hs.

Next, referring to FIGS. 3 and 6, the tooth width Lyt of the magnetizing outer yoke 2 and the outer peripheral length Lro of the rotor 6 will be described.
The relationship with the magnetic flux density of the magnet will be described.

As shown in FIG. 6, the value obtained by quadrupling the tooth width Lyt of the magnetizing outer yoke 2 is the outer peripheral length Lr of the rotor 6.
By being equal to or more than o, the magnetic flux density of the magnet can be improved. That is, when the total of the tooth widths Lyt of the magnetizing outer yoke 2 shown in FIG. 3 is equal to or longer than the outer peripheral length Lro of the rotor 6, the magnetic flux density of the magnet can be improved.

Next, referring to FIG. 3 and FIG.
The relationship between the radial length (back yoke dimension) Lyy of the magnetizing outer yoke 2 in the portion where a is provided, the tooth width Lyt of the magnetizing outer yoke 2, and the magnetic flux density of the magnet will be described.

As shown in FIG. 7, when the back yoke dimension Lyy is equal to or more than の of the tooth width Lyt, the magnetic flux density of the magnet can be improved. It is shown in Figure 1
Since the magnetic flux passing outside the adjacent slots 2a merges at the teeth 2b as shown in FIG.
This is because by setting yy to be equal to or more than １ ／ of the tooth width Lyt, it is possible to increase the magnetic flux that is effective for magnetization, as in the above-described cases.

The magnetizing is performed using the magnetizing external yoke 2 having the above-described characteristics, so that the stator windings 4 are formed.
There is no need to energize the battery. As a result, it is possible to prevent the occurrence of stress when the stator winding 4 is magnetized, and it is possible to significantly reduce stator defects. In addition, a fixing agent to be applied to the stator winding 4 is not required, so that the cost can be reduced. Furthermore, since there is no need to energize the stator windings 4, there is no restriction on the magnetizing force, and an electromagnetic design specializing in demagnetization resistance and motor efficiency becomes possible.

(Embodiment 2) Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 8 is a sectional view showing a magnetizing method according to the second embodiment of the present invention.

In the first embodiment shown in FIG. 1, the external yoke winding 5 is wound around the teeth 2b of the external yoke 2 for magnetization. On the other hand, in the second embodiment, as shown in FIG. 8, the external yoke winding 5 is wound around the yoke of the external yoke 2 for magnetization. As a result, the space factor is doubled, and the winding resistance of the magnetizing external yoke 2 can be reduced. Thereby, a stronger magnetic field can be generated at the same voltage as compared with the case of the first embodiment.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 9 is a sectional view showing a magnetizing method according to Embodiment 3 of the present invention.

Referring to FIG. 9, in the third embodiment, 1
The external yoke winding 5 is wound around only one slot 2a. Thereby, the magnet can be magnetized one pole at a time. By magnetizing one pole at a time in this way, compared to the case of simultaneously magnetizing a plurality of poles using the same magnetizing power supply,
Magnetization energy per pole can be increased.
For example, compared to the case of four-pole magnetization as in the first embodiment, it is possible to generate four times the magnetizing energy per magnet. As a result, the magnetizing power supply capacity can be reduced, and the capital investment amount can be reduced.

(Embodiment 4) Next, referring to FIG.
Embodiment 4 of the present invention will be described. FIG.
FIG. 13 is a cross-sectional view illustrating a magnetizing method according to Embodiment 4 of the present invention.

Referring to FIG. 10, in the fourth embodiment,
The magnetizing outer yoke 2 is a quarter of the case shown in FIG. In this manner, the shape of the magnetizing outer yoke 2 may be modified to magnetize one pole at a time. Also in this case, the same effect as that of the above-described third embodiment can be obtained.

(Embodiment 5) Next, referring to FIG.
Embodiment 5 of the present invention will be described. FIG.
FIG. 14 is a cross-sectional view showing a magnetizing method according to Embodiment 5 of the present invention.

Referring to FIG. 11, the outer periphery of stator 3 may be provided with a core cut 3c for passing a refrigerant gas or oil. In the portion where the core cut 3c is provided, the flow of the magnetic flux 8 is obstructed. Therefore, as shown in FIG. 11, the core cut 3c and the magnetizing external yoke 2
Slot 2a. Thereby,
The flow of the magnetic flux 8 can be prevented from being hindered by the core cut 3c, and the magnetization can be performed efficiently.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described with reference to FIGS.
Magnetization using the above-described magnetizing external yoke 2 causes a large leakage of magnetic flux, so that a larger current is required as compared with a case where magnetizing is performed by energizing only the stator winding 4. Therefore, it is necessary to increase the capacity of the magnetized power supply. Also,
Large magnetizing stress also occurs in the external yoke winding 5, and a large-scale winding fixing method is required. Therefore, the amount of capital investment can be large. Furthermore, since the stress at the time of magnetizing the outer yoke winding 5 becomes extremely large, there is a concern that the durability of the magnetizing outer yoke 2 itself may be reduced.

Therefore, in the sixth embodiment, the magnetization is performed by energizing both the external yoke winding 5 and the stator winding 4. Thus, the value of the current flowing through the external yoke winding 5 can be reduced, and the capacity of the magnetized power supply can be reduced. In addition, the stress generated in the outer yoke winding 5 can be reduced, and the capital investment for fixing the winding can be reduced. Further, since the magnetizing stress generated in the outer yoke winding 5 can be reduced, the durability of the magnetizing outer yoke 2 itself can be improved. This can also contribute to a reduction in capital investment.

Table 1 below shows the allowable current value of the stator winding 4 when the magnetizing outer yoke 2 and the stator 3 are used together.

[0064]

[Table 1]

As shown in Table 1 above, at a current value (I × I / Io) lower than the allowable current I for winding deformation, a magnetic flux equivalent to that in the case of 100% magnetization using a stator is generated. be able to. At this time, the force applied to the stator winding 4 is kept within an allowable range.

FIG. 12 shows a magnetizing circuit (a) in the case of magnetizing using only the magnetizing external yoke 2 and a magnetizing circuit (in which the magnetizing external yoke 2 and the stator 3 are used in combination. b) are shown. By using the stator 3 and the magnetizing external yoke 2 together, the magnetizing can be performed using the magnetic field generated in both, so that the current value is lower than the current value Ia required when only the magnetizing external yoke 2 is used. Magnetization can be performed with the current value Ib.

As shown in FIG. 12B, the stator 3 and the magnetizing outer yoke 2 are connected in parallel to a magnetizing power supply. As a result, the same voltage can be applied to the stator winding 4 and the external yoke winding 5, and a desired magnetic field can be generated for each. Then, the magnets are magnetized by a synthesized magnetic field obtained by synthesizing them so that the external yoke winding 5
The value of the current flowing through the stator winding 4 can be reduced as compared with the above-described embodiments, and the current flowing through the stator winding 4 can be reduced as compared with the related art.

FIG. 13 shows a combined magnetic field when the magnetizing outer yoke 2 and the stator 3 are used together. FIG.
3, the maximum combined magnetic field can be generated by synchronizing the waveform of the current flowing through external yoke winding 5 with the waveform of the current flowing through stator winding 4. By magnetizing using the maximum combined magnetic field, the value of the current flowing through the external yoke winding 5 and the stator winding 4 can be effectively reduced.

To synchronize the waveform of the current flowing through the external yoke winding 5 with the waveform of the current flowing through the stator winding 4,
As shown in FIG. 12B, the synchronization coil (L),
A synchronization element such as a resistor (R) is connected in series with the stator winding 4. Thereby, the phase of the current flowing through the stator winding 4 can be shifted, and the waveform of the current flowing through the stator winding 4 and the waveform of the current flowing through the external yoke winding 5 can be synchronized.

(Seventh Embodiment) Next, a seventh embodiment of the present invention will be described with reference to FIGS.
FIG. 4 is a sectional view showing a magnetizing method according to Embodiment 7 of the present invention.

As shown in FIG. 14, in the seventh embodiment, the magnetic ring 9 having no slot is arranged outside the compressor casing 1. In this manner, the magnet ring can be magnetized simply by disposing the magnetic ring 9 outside the compressor casing 1 by supplying a lower current to the stator winding 4 than in the related art. The reason will be described below.

FIG. 15 shows the relationship between the ratio of the back yoke dimension (Lsy) to the predetermined tooth width (Lst) and the magnetizing current reduction rate. From the results shown in FIG. 15, it can be seen that the current value required for magnetization decreases as the back yoke dimension (Lsy) increases. By installing the magnetic ring 9 as shown in FIG.
The size of the back yoke is Lsy1, and the size of the back yoke can be increased as compared with the case where magnetization is performed using only the stator 3. In other words, by providing the magnetic ring 9, the value of the current flowing through the stator winding 4 can be reduced.

As described above, it is only necessary to attach the annular magnetic ring 9 to the outside of the compressor casing 1, so that the value of the current flowing through the stator winding 4 can be reduced simply and reliably. Further, since it is only necessary to newly prepare the magnetic ring 9, the cost required for it can be kept low.

Next, the back yoke dimension Lsy will be described in more detail. FIG. 16 shows the flow of the magnetic flux 8 in the case where only the stator winding 4 is energized and magnetized.

As shown in FIG. 16, the magnetic flux 8 flows in a circle from the stator 3, the rotor 6, the magnet 7, the rotor 6, and the stator 3. Therefore, the magnetic flux flowing through the stator 3 and the magnetic flux flowing through the magnet 7 are the same.

Here, for example, the magnet 7 which is a rare earth magnet
Assuming that the magnetic flux required for magnetizing the stator 3 is Bm [T], the saturation magnetic flux density of the stator 3 is By [T], the radius of the rotor 6 is r, and the thickness of the stator 3 is hs, The magnetic flux flowing through the yoke to the rotor 6 is Bm × 2 ×
π × r / 8 × hs, and the maximum magnetic flux that can flow through the stator 3 can be represented by By × Lsy × hs.

In order to use the magnetic material efficiently, it is preferable to use the magnetic material at a saturation magnetic flux density or less. Therefore, when the magnetic flux flowing into the rotor 6 is set to be equal to or less than the maximum magnetic flux that can flow through the stator 3, the following relational expression is obtained.

Bm × 2 × π × r / 8 × hs ≦ By × Lsy × hs When the back yoke dimension Lsy is obtained from the above relational expression,
It looks like this:

Lsy ≧ １ ／ × π × r × Bm / By Thus, the back yoke dimension Lsy is set to １ ／ × π × r ×
By setting Bm / By or more, a magnetic flux less than or equal to the maximum magnetic flux that can flow through the stator 3 can flow through the rotor 6 to magnetize the magnet 7. For this reason, the magnetic material such as the stator 3 can be used efficiently at a saturation magnetic flux density or less, and as a result, the value of the current flowing through the stator winding 4 can be reduced as compared with the conventional case.

As a result, when the back yoke dimension Lsy cannot be ensured only by the stator 3, the above-described magnetic ring 9 may be mounted on the outer periphery of the compressor casing 1. By attaching the magnetic ring 9, the radial width of the magnetic ring 9 is added to the back yoke dimension Lsy, and the back yoke dimension Lsy is set to L as described above.
sy1. In this case, Ls
The above effect can be obtained by setting y1 to １ ／ × π × r × Bm / By or more.

Although the embodiments of the present invention have been described above, it should be understood that the embodiments disclosed herein are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0082]

As described above, according to the method for magnetizing a permanent magnet type electric motor according to any one of the first to tenth aspects, the value of the current flowing through the stator winding can be reduced as compared with the related art. Thereby, the stator failure can be effectively reduced. Further, by setting the value of the current supplied to the stator winding to be equal to or less than the allowable current for the deformation of the winding, a fixing agent for the stator winding is not required, and the cost can be reduced.

Further, in the magnetizing method according to the third aspect, since it is not necessary to energize the stator winding, a fixing agent for the stator winding is not required, and the cost can be reduced. In addition, if the design to increase the demagnetization resistance and the motor efficiency is performed in the motor electromagnetic design, the magnetizing force required for magnetization increases, but as described above, there is no need to supply current to the stator windings, so the magnetizing force is limited. Therefore, an electromagnetic design specialized in demagnetization resistance and motor efficiency becomes possible.

In the magnetizing method according to the fourth aspect, since the capacity of the magnetizing power supply can be reduced, the capital investment can be reduced.

In the magnetizing method according to the sixth to ninth aspects, the magnetic field by the magnetizing member and the magnetic field by the stator can be combined and magnetized, so that the magnetizing is performed using only the magnetizing member. As compared with the case, the value of the current flowing through the winding of the magnetizing member can be reduced. As a result, it is possible to reduce the capital investment for the magnetizing power supply and the winding fixing.
In addition, the durability of the magnetizing member can be improved.

According to the magnetizing method of the tenth aspect, it is not necessary to attach a winding to the annular magnetic body functioning as a magnetizing member, so that the cost required for the magnetizing member can be reduced. Further, the capacity of the magnetized power supply can be reduced, and a significant cost reduction can be expected.

According to the magnetizing member of the present invention, since the value of the current flowing through the stator winding can be reduced, the defective stator can be effectively reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magnetizing method according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view showing a state in which an external yoke for magnetization according to the present invention is installed outside a compressor casing.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 2;

FIG. 4 shows the magnetic flux density of the magnet and the thickness h of the external yoke for magnetization.
It is a figure which shows the relationship between y and the thickness hs of a stator.

FIG. 5 shows the magnetic flux density of the magnet and the tooth width L of the external yoke for magnetization.
It is a figure which shows the relationship between yt and the tooth width Lst of a stator.

FIG. 6 shows the magnetic flux density of the magnet and the tooth width L of the external yoke for magnetization.
It is a figure which shows the relationship between yt and the outer peripheral length Lro of a rotor.

FIG. 7 is a diagram showing the relationship between the magnetic flux density of the magnet, the yoke width Lyy of the magnetizing external yoke, and the tooth width Lyt of the magnetizing external yoke.

FIG. 8 is a sectional view showing a magnetizing method according to a second embodiment of the present invention.

FIG. 9 is a sectional view showing a magnetizing method according to a third embodiment of the present invention.

FIG. 10 is a sectional view showing a magnetizing method according to a fourth embodiment of the present invention.

FIG. 11 is a sectional view showing a magnetizing method according to a fifth embodiment of the present invention.

12A is a diagram showing a magnetized circuit when only a magnetizing external yoke is used, and FIG. 12B is a diagram showing a magnetized circuit when both a stator and a magnetizing external yoke are used. is there.

FIG. 13 is a diagram showing a magnetic field generated by a magnetizing external yoke, a magnetic field generated by a stator, and a combined magnetic field obtained by combining them.

FIG. 14 is a sectional view showing a magnetizing method according to a seventh embodiment of the present invention.

FIG. 15 is a diagram illustrating a relationship between a ratio of a back yoke dimension Lsy to a predetermined tooth width Lst and a magnetizing current reduction rate.

FIG. 16 is a diagram showing a flow of a magnetic flux when current is applied only to a stator winding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor casing 2 External yoke for magnetization 2a, 3a Slot 2b, 3b Teeth 3 Stator 3c Core cut 4 Stator winding 5 External yoke winding 6 Rotor 7 Magnet 8 Magnetic flux 9 Magnetic ring

Continued on the front page. (72) Katsutaka Hara, 2-1, Oya, Okamoto-cho, Kusatsu-shi, Shiga Prefecture. Daiga Industries Co., Ltd., Shiga Works. (72) Hiroaki Kojima, 1000-2 Oya, Okamoto-cho, Kusatsu-shi, Shiga. Daikin Industries, Ltd. Shiga Works (72) Inventor Masatoshi Hirano 1000, Oya, Okamoto-cho, Kusatsu-shi, Shiga 2 Daikin Industries, Ltd. Shiga Works (72) Inventor Yasukazu Nabetaya Oya-1000, Okamoto-cho, Kusatsu-shi, Shiga Address 2 Daikin Industries, Ltd. Shiga Works

Claims (16)

[Claims] 1. A method of magnetizing a permanent magnet type electric motor that magnetizes a magnet fitted in a rotor (6) in a state of being assembled in a casing (1), wherein the magnet is disposed outside the casing (1). And magnetizing the magnet using a magnetizing member (2). 2. A stator (3) for the permanent magnet type electric motor.
And windings (4, 4) on at least one of the magnetizing members (2).
The method according to claim 1, wherein the magnet is magnetized by energizing the windings (4, 5). 3. The method for magnetizing a permanent magnet type electric motor according to claim 2, wherein current is applied only to the windings (5) of the magnetizing member (2). 4. The method according to claim 3, wherein a plurality of the magnets are fitted to the rotor, and each of the magnets is individually magnetized. 5. A notch (3c) is provided on an outer periphery of the stator (3), and a slot (2a) for receiving the winding (5) is formed on an inner periphery of the magnetizing member (2). The method according to claim 2, wherein the windings (4, 5) are energized while the notch (3c) and the slot (2a) are aligned. 6. A winding (4, 5) is attached to both the stator (3) and the magnetizing member (2), and each of the windings (4, 5) is energized. 3. The method for magnetizing a permanent magnet type electric motor according to item 1. 7. The waveform of a current flowing through a winding (4) of the stator (3) and a waveform of a current flowing through a winding (5) of the magnetizing member (2) are synchronized. A magnetizing method for the permanent magnet type electric motor according to the above. 8. An element for synchronizing the current waveform is connected in series with the winding (4) of the stator (3).
A method for magnetizing a permanent magnet type electric motor according to claim 7. 9. The permanent magnet type according to claim 6, wherein the winding (4) of the stator (3) and the winding (5) of the magnetizing member (2) are connected in parallel to a magnetizing power supply. How to magnetize the motor. 10. The permanent magnet type according to claim 2, wherein the magnetizing member (2) is formed of an annular magnetic body (9), and energizes only the winding (4) of the stator (3). How to magnetize the motor. 11. A magnetized magnet, which is disposed outside the casing (1) for magnetizing a magnet fitted to a rotor (6) in a permanent magnet type electric motor incorporated in the casing (1). Parts. 12. An axial thickness (hy) of the magnetizing member (2) in an axial direction (hs) of a yoke of a stator (3) of the permanent magnet type electric motor.
3. The magnetizing member according to claim 1. 13. The stator (3) of the permanent magnet electric motor has a first slot (3a) and first teeth (3b) provided on both sides of the first slot (3a). The magnetizing member (2) includes a second slot (2a);
Second teeth provided on both sides of the second slot (2a), and the sum of the tooth widths (Lyt) of the second teeth (2b) is equal to that of the first teeth (3b). Is greater than or equal to the sum of the tooth widths (Lst),
The member for magnetization according to claim 11. 14. The magnetizing member (2) has a slot (2a) and teeth (2b) provided on both sides of the slot (2a), and has a tooth width (2) of the teeth (2b). The magnetizing member according to claim 11, wherein a total sum of Lyt) is equal to or longer than an outer peripheral length (Lro) of the rotor (6). 15. The magnetizing member (2) has a slot (2a) and teeth (2b) provided on both sides of the slot (2a), and the slot (2a) is provided. The magnetizing member according to claim 11, wherein the radial width (Lyy) of the portion of the magnetizing member (2) is equal to or more than 以上 of the tooth width (Lyt) of the teeth (2b). 16. The magnetizing member (9) is an annular magnetic body mounted on an outer periphery of the casing, the permanent magnet type electric motor has a stator (3), and the stator (3) ) Is the total width of the radial width (Lsy) of the yoke and the radial width of the magnetizing member (9).
1, the magnetic flux density required for magnetizing the magnet is Bm,
Assuming that the saturation magnetic flux density of the yoke of the stator (3) and the magnetizing member (9) is By and the radius of the rotor (6) is r, the total width Lsy1 is １ ／ × π × r The member for magnetization according to claim 11, which is at least × Bm / By.