JP2001186701A - Permanent magnet rotor of motor and enclosed compressor using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid crackings in a permanent magnet, which is caused by the press-fit or shrinkage fit of a crank shaft, to provide a permanent magnet rotor having excellent reliability and to provide a small size, low cost, low noise and low vibration enclosed compressor. SOLUTION: This permanent magnet rotor of a motor comprises a layer-built iron plate core 9, which has a through hole 15 at a center thereof, and a crank shaft, which is fitted to the through hole 15 by pressure or shrinkage. A plurality of relief holes 20, with circular arc cross-sections, are formed in the neighborhood of the through hole 15 so as to surround the through hole 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet rotor for an electric motor and a hermetic compressor using the same.

[0002]

2. Description of the Related Art Conventionally, permanent magnet rotors of electric motors used for hermetic compressors and the like are disclosed in Japanese Patent Application Laid-Open Nos. 2-184231 and 5-304751, as disclosed in Japanese Patent Application Laid-Open Nos. Hei 5-3044751. The inside of the rotor and the outer periphery of the rotor are arranged so that magnets are not scattered by centrifugal force during rotation and that magnet powder etc. leak as much as possible to the outside of the rotor. A plurality of permanent magnets incorporated in the inside of a laminated iron plate core as described in Japanese Patent Application Laid-Open No. 9-84285, etc. The structure is such that powder and the like do not leak outside the rotor as much as possible. These permanent magnet rotors are usually used by fixing them to a crankshaft, and the fixing method includes press-fitting and a method of heating a shaft insertion hole as described in JP-A-7-194071. .

When a conventional permanent magnet rotor is used in a hermetic compressor, a thin plate or the like is provided at one or both ends in the axial direction of the permanent magnet rotor in order to correct imbalance caused by a compression mechanism. Had been added. Further, in such a hermetic compressor, the stator of the electric motor is usually fixed in close contact with the circumferential housing (body shell), so that a through-groove is formed in the outer periphery of the stator as a refrigerant passage communicating from suction to discharge. Was provided.

FIG. 12 shows a horizontal scroll compressor as an example of a hermetic compressor incorporating a conventional permanent magnet rotor, which will be described below with reference to the drawings. In the scroll compressor shown in FIG. 12, the refrigerant taken in from a suction port 2 at one end of a horizontal housing (body shell) 1 is compressed and discharged by a compression mechanism section composed of a movable scroll 3 and a fixed scroll 4. As described above, through the through hole 5 provided in the vicinity of the outer periphery of the compression mechanism portion, through the through groove 7 provided in the outer periphery of the stator 6 of the electric motor which is the driving portion, and from the compressor discharge port 8 on the other end side of the housing 1. It is to be exhaled.

More specifically, in the compression mechanism, a crescent-shaped air chamber composed of a movable scroll 3 and a fixed scroll 4 passes through a stator 6 and a laminated iron core 9 constituting a permanent magnet rotor. Iron core 9 is fixed and bearing member 1
The rotation force from the electric motor transmitted through the crankshaft 12 supported by the rotation shafts 0 and 11 reduces the volume from the outer periphery toward the center by the turning motion converted by the rotation prevention mechanism 13. . At this time, the crankshaft 12 undergoes a whirling motion under the load from the compression mechanism, so that the crankshaft 12 is in an unbalanced state. To avoid this, a balance weight such as a thin plate 14 is usually added to the rotor end face. Was adjusting the balance.

[0006]

However, when the crankshaft 12 is press-fitted or shrink-fitted into the laminated iron core 9 constituting the conventional permanent magnet rotor, the crankshaft insertion through-hole provided at the center of the laminated iron core 9 is provided. Due to the deformation of the hole, there is a problem that the permanent magnet installed on the outer periphery or inside of the laminated iron core 9 is easily broken and lacks insertability and reliability.

Further, when a conventional permanent magnet rotor is used in the hermetic compressor and a balance weight such as a thin plate member 14 is added to correct imbalance, the hermetic compressor has a long overall length. , Miniaturization, reduction in the number of parts, and cost reduction are hindered. Further, the stator 6 of the electric motor in such a hermetic compressor includes:
As a refrigerant passage communicating from suction to discharge, a through groove 7 is formed on the outer periphery.
Is provided, the fixing of the stator 6 becomes unstable, which hinders noise and vibration reduction.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and provides a permanent magnet rotor which prevents permanent magnets from being cracked by press-fitting or shrink-fitting of a crankshaft and which is excellent in reliability. An object of the present invention is to provide a small-sized, low-cost, low-noise, low-vibration hermetic compressor using this.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a through hole at the center of a laminated iron plate iron core of a permanent magnet rotor, and a relief portion at an outer periphery near the through hole. Utilizing this relief part, it corrects the rotational imbalance of the hermetic compressor using the permanent magnet rotor,
Alternatively, an escape portion is used in the refrigerant passage.

By providing a relief portion around the center of the laminated iron core of the permanent magnet rotor near the through hole, cracks of the permanent magnet installed on the outer periphery or inside of the laminated iron core are prevented, and insertability and reliability are improved. An excellent permanent magnet rotor can be obtained, and by using the permanent magnet rotor having the relief portion, a small-sized, low-cost, low-noise, low-vibration hermetic compressor can be obtained.

[0011]

The invention according to claim 1 is a permanent magnet rotor for an electric motor in which a through-hole is provided at the center of a laminated iron core and a crankshaft is press-fitted or shrink-fitted into the through-hole. An escape portion is provided near the through hole. According to this configuration, when the crankshaft is press-fitted or shrink-fitted into the permanent magnet rotor, deformation of the crankshaft insertion through hole provided at the center of the laminated iron core is avoided inside the laminated iron core, and A permanent magnet rotor having excellent insertability and reliability can be obtained by preventing cracks of the permanent magnet installed on the outer periphery or inside of the iron core.

According to a second aspect of the present invention, there is provided the permanent magnet rotor according to the first aspect, wherein the escape portion includes a plurality of escape holes having an arc-shaped cross section surrounding the through hole. The escape portion can be efficiently arranged in the iron plate iron core, and the entire permanent magnet can be prevented from cracking, so that a permanent magnet rotor excellent in insertability and reliability can be obtained.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the permanent magnet rotor described, a plurality of arcuate permanent magnets are arranged on the outer periphery of a laminated iron core, and the outer periphery is fixed by a non-magnetic metal tube. At the time of fitting and fixing, it is possible to prevent a plurality of bow-shaped magnets arranged on the outer periphery from hitting the non-magnetic metal tube due to deformation of the laminated iron plate core, and to obtain a permanent magnet rotor excellent in insertability and reliability.

The invention described in claim 4 is the first or second invention.
The permanent magnet rotor described in which a plurality of arcuate permanent magnets are disposed inside the laminated iron core. According to this configuration, when the crankshaft is press-fitted or shrink-fitted, it is disposed inside the laminated iron core. The plurality of arcuate permanent magnets can be prevented from being cracked due to deformation of the laminated iron core, and a permanent magnet rotor having excellent insertability and reliability can be obtained.

According to a fifth aspect of the present invention, there is provided the permanent magnet rotor according to the third aspect, wherein a plurality of relief holes are formed when viewed from a circumferential direction.
According to this configuration, when the crankshaft is press-fitted or shrink-fitted and fixed, the plurality of arcuate permanent magnets disposed on the outer periphery are viewed from the circumferential direction. Both ends can be reliably prevented from being pressed by the deformation of the laminated iron core and hitting the non-magnetic metal tube near the center of the permanent magnet as viewed from the circumferential direction, and a permanent magnet rotor with excellent insertability and reliability. can get.

According to a sixth aspect of the present invention, there is provided the permanent magnet rotor according to the fourth aspect, wherein a plurality of relief holes are formed when viewed from a circumferential direction.
Which are arranged in the same direction as the plurality of arcuate permanent magnets,
According to this configuration, at the time of press-fitting or shrink-fitting of the crankshaft, the vicinity of the center of the plurality of arcuate permanent magnets arranged inside the laminated iron core viewed from the circumferential direction is pressed by the deformation of the laminated iron core. Further, the vicinity of the center of the permanent magnet viewed from the circumferential direction can be reliably prevented from being cracked inside the laminated iron core, and a permanent magnet rotor having excellent insertability and reliability can be obtained.

According to a seventh aspect of the present invention, there is provided the permanent magnet rotor according to any one of the first to sixth aspects, wherein a plurality of through holes are provided in the iron plate by press forming, and the iron plates are laminated. It is an iron plate iron core. According to this configuration, the penetrated escape hole can be easily formed in the laminated iron core, and can be manufactured at low cost.

According to an eighth aspect of the present invention, an electric motor handling the permanent magnet rotor according to any one of the first to seventh aspects is housed in a closed container, and the rotating force of the motor is bearing in the closed container. This is a hermetic compressor provided with a compression mechanism portion that is driven by being transmitted by a crankshaft supported by a member. According to this configuration, the motor section of the compressor can be easily assembled, and a hermetic compressor excellent in productivity can be obtained.

According to a ninth aspect of the present invention, in the hermetic compressor according to the eighth aspect, in order to correct the rotational imbalance of the compression mechanism, the size of the plurality of through holes is made different to adjust the balance. It is configured as follows. According to this configuration, a thin plate material for correcting imbalance can be eliminated, and a hermetic compressor excellent in miniaturization, reduction in the number of parts, cost reduction, and the like can be obtained.

According to a tenth aspect of the present invention, in the hermetic compressor according to the eighth or ninth aspect, a refrigerant gas path for flowing the refrigerant compressed by the compression mechanism from one end face to the other end face of the permanent magnet rotor is provided. In this case, the pierced escape hole is a part of the gas path. And according to this configuration,
There is no need to provide a through-groove, which is a refrigerant passage communicating from the suction port to the discharge port, on the outer periphery of the stator of the electric motor in the hermetic compressor, and the stator is securely attached to the circumferential housing (body shell). Because it can be fixed, a hermetic compressor with low noise and low vibration can be obtained.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same members as those of the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted. (Embodiment 1) In FIGS. 1 to 4, a laminated iron core 9 has a through hole 15 at its center for press-fitting or shrink-fitting a crankshaft, and a plurality of arc-shaped permanent magnets 16 are arranged on the outer periphery. In order to prevent the magnet from scattering due to the centrifugal force at the time of rotation, and to prevent magnet powder and the like from leaking outside the rotor as much as possible, the outer periphery of the rotor is made of a non-magnetic metal tube 17 and both end surfaces in the axial direction are made of plates 18. , And integrated with caulking pins 19 to form a permanent magnet rotor.

Here, in the permanent magnet rotor shown in FIG. 3 as Comparative Example 1, the through hole 15 for inserting the crankshaft provided in the center of the laminated iron core 9 is formed by press-fitting or shrink fitting. Spreading in the radial direction by heating from above causes deformation of the laminated iron core 9 as shown by the arrow, compresses the permanent magnet 16 arranged on the outer periphery, hits the non-magnetic metal tube 17, and causes cracks as shown in the figure. Cheap. In addition, such cracks are caused by the arc-shaped permanent magnets 16 arranged on the outer peripheral portion.
Many are due to compression at both ends as viewed from the circumferential direction.

Therefore, in the first embodiment, a plurality of escape holes 20 having a circular arc cross section are provided so as to surround the through hole 15 near the through hole 15 provided at the center of the laminated iron core 9. From this, as shown in FIG.
The radial expansion due to heating from the inner surface of the through-hole 15 by press-fitting or shrink-fitting of the through-hole 15 for inserting a crankshaft provided at the center of the crankshaft is absorbed inside the laminated iron plate iron core 9 as shown by the arrow. , Permanent magnet 16 arranged on the outer periphery
Pressure can be avoided. In particular, the permanent magnet 16
In the case where is shaped like an arc, the above-described avoiding effect can be ensured by arranging the penetrated escape hole 20 between a plurality of permanent magnets when viewed from the circumferential direction. The plate 18 also has a hole 18a connected to the escape hole 20 and a hole 18b connected to the through hole 15.

(Embodiment 2) In FIGS. 5 to 8, the laminated iron core 9 has a through hole 15 at the center for press-fitting or shrink-fitting the crankshaft. A plurality of permanent magnets 16 are arranged, both end surfaces in the axial direction are covered with a plate 18, and integrated with caulking pins 19 to constitute a permanent magnet rotor.

Here, in the permanent magnet rotor shown in FIG. 7 as Comparative Example 2, the through hole 15 for inserting the crankshaft provided at the center of the laminated iron plate iron core 9 is formed by press-fitting or shrink fitting. The steel sheet spreads in the radial direction due to heating from above, causing deformation of the laminated iron core 9 as shown by the arrow, pressing the permanent magnet 16 disposed inside, and easily causing cracks as shown in the figure. Such cracks are often caused by pressure near the center of the arcuate permanent magnet 16 disposed inside when viewed from the circumferential direction.

Therefore, in the second embodiment, a plurality of escape holes 20 having a circular arc cross section are provided so as to surround the through hole 15 near the through hole 15 provided at the center of the laminated iron core 9. From this, as shown in FIG.
The radial expansion due to heating from the inner surface of the through-hole 15 by press-fitting or shrink-fitting of the through-hole 15 for inserting a crankshaft provided at the center of the crankshaft is absorbed inside the laminated iron plate iron core 9 as shown by the arrow. , The permanent magnet 16 arranged inside
Pressure can be avoided. In particular, the permanent magnet 16
In the case where is shaped like an arc, the above-described avoiding effect can be ensured by arranging the penetrated escape holes 20 in the same direction as the plurality of permanent magnets when viewed from the circumferential direction. In addition,
The plate 18 also has a hole 18 connected to the escape hole 20.
a and a hole 18b connected to the through hole 15 are formed.

(Embodiment 3) In FIGS. 9 to 11, the laminated iron core 9 has a through hole 15 for press-fitting or shrink-fitting the crankshaft 12 at the center, and an arc-shaped permanent magnet 16 on the outer periphery. The outer periphery of the rotor is provided with a non-magnetic metal tube 17 so that magnets are not scattered by centrifugal force during rotation and magnet powder and the like do not leak outside the rotor as much as possible.
Further, both ends in the axial direction are covered with a plate 18 and integrated with caulking pins 19 to constitute a permanent magnet rotor.

Here, in the hermetic compressor shown in FIG. 12 described in the above conventional example, the crankshaft undergoes a whirling motion under the load from the compression mechanism, so that the crankshaft is in an unbalanced state. To avoid this, a balance weight such as a thin plate was added to the rotor end face to adjust the balance. On the other hand, in the third embodiment, a plurality of escape holes 20 having an arcuate cross section penetrated so as to surround the through hole 15 near the through hole 15 provided at the center of the laminated iron core 9.
And the size of the escape holes 20 is made different from each other, or the size of at least one of the escape holes 20 is made different from the size of the other escape holes 20 to adjust the balance. According to this configuration, a thin plate material for correcting imbalance can be eliminated, and a hermetic compressor excellent in miniaturization, reduction in the number of parts, cost reduction, and the like can be obtained. The plate 18 also has a hole 18a connected to the escape hole 20 and a hole 18b connected to the through hole 15.

(Embodiment 4) In FIG. 11, the laminated iron core 9 has a through hole 15 for press-fitting or shrink-fitting the crankshaft 12 at the center, and a bow-shaped permanent magnet (not shown) on the outer periphery. The outer periphery of the rotor is made of a non-magnetic metal tube 1 so that magnets are not scattered due to centrifugal force at the time of rotation and magnet powder and the like do not leak outside the rotor as much as possible.
7 and both end surfaces in the axial direction are covered with a plate 18 and integrated with caulking pins to form a permanent magnet rotor similar to that of the third embodiment.

Here, in the hermetic compressor shown in FIG. 12 described in the above conventional example, the refrigerant taken in from the suction port 2 of the compressor is compressed and discharged by the compression mechanism, and as shown by the arrow, the compression mechanism Through a through hole 5 provided in the vicinity of the outer periphery, it passes through a through groove 7 provided in the outer periphery of the stator 6 of the electric motor which is a driving portion, and is discharged from a compressor discharge port 8 on the other end side of the housing 1. ing.

Therefore, in the fourth embodiment, the refrigerant compressed by the above-mentioned compression mechanism is formed so as to surround the through hole 15 near the through hole 15 so as to flow from one end face to the other end face of the permanent magnet rotor. The plurality of escape holes 20 penetrated form a part of the refrigerant gas path. The plate 1
8 also has a hole 18a connected to the relief hole 20 and a hole 18b connected to the through hole 15. According to this configuration, it is not necessary to provide a through groove 7 which is a refrigerant passage communicating from the suction port 2 to the discharge port 8 on the outer periphery of the stator 6 of the electric motor in the hermetic type compressor, and the stator 6 has a circumferential shape. Since it can be securely fixed in close contact with the housing (body shell) 1 in one direction, a hermetic compressor with low noise and low vibration can be obtained.

[0032]

As is apparent from the above embodiment, according to the first aspect of the present invention, a through-hole is provided at the center of the laminated iron sheet core,
In a rotor of a permanent magnet motor in which a crankshaft is press-fitted or shrink-fitted into this through-hole, a relief portion is provided on the outer periphery near the through-hole. According to this configuration, the crankshaft is press-fitted into the permanent magnet rotor. Or, when shrink-fitting and fixing, avoid deformation of the through hole for crankshaft insertion provided in the center of the laminated iron core inside the laminated iron core, prevent cracking of the permanent magnet installed on the outer periphery or inside the laminated iron core, and insert sex,
A highly reliable permanent magnet rotor can be obtained.

According to a second aspect of the present invention, there is provided the permanent magnet rotor according to the first aspect, wherein the shape of the relief portion is a plurality of arc-shaped through holes (release holes) surrounding the through hole. According to this, the escape portion can be efficiently arranged in the laminated iron plate iron core, cracks can be prevented for the entire permanent magnet, and a permanent magnet rotor excellent in insertability and reliability can be obtained. According to a third aspect of the present invention, there is provided the permanent magnet rotor according to the first or second aspect, wherein a plurality of bow-shaped magnets are arranged on the outer periphery of the laminated iron core, and the outer periphery is fixed by a non-magnetic metal tube. According to this configuration, at the time of press-fitting or shrink-fitting the crankshaft,
It is possible to prevent a plurality of bow-shaped magnets arranged on the outer circumference from hitting the non-magnetic metal tube by the deformation of the laminated iron core and cracking,
A permanent magnet rotor excellent in insertability and reliability can be obtained.

The invention according to claim 4 is the invention according to claim 1 or 2
The permanent magnet rotor described in which a plurality of arcuate permanent magnets are disposed inside the laminated iron core. According to this configuration, when the crankshaft is press-fitted or shrink-fitted, it is disposed inside the laminated iron core. The plurality of arcuate permanent magnets can be prevented from being cracked due to deformation of the laminated iron core, and a permanent magnet rotor having excellent insertability and reliability can be obtained.

According to a fifth aspect of the present invention, there is provided the permanent magnet rotor according to the third aspect, wherein the plurality of through holes are disposed between the plurality of arcuate magnets when viewed from a circumferential direction. According to this configuration, at the time of press-fitting or shrink-fitting of the crankshaft, both ends of the plurality of arcuate magnets arranged on the outer periphery viewed from the circumferential direction are pressed by deformation of the laminated iron plate core,
The non-magnetic metal tube can be reliably prevented from breaking near the center of the permanent magnet viewed from the circumferential direction, and a permanent magnet rotor excellent in insertability and reliability can be obtained.

According to a sixth aspect of the present invention, in the permanent magnet rotor according to the fourth aspect, when viewed from the circumferential direction, the plurality of pierced relief holes are arranged in the same direction as the plurality of arcuate magnets. According to this configuration, at the time of press-fitting or shrink fitting of the crankshaft, the vicinity of the center as viewed from the circumferential direction of the plurality of bow-shaped magnets disposed inside the laminated iron core is pressed by deformation of the laminated iron core. Therefore, the vicinity of the center of the permanent magnet viewed from the circumferential direction can be reliably prevented from being cracked inside the laminated iron core, and a permanent magnet rotor having excellent insertability and reliability can be obtained.

According to a seventh aspect of the present invention, there is provided the permanent magnet rotor according to any one of the first to sixth aspects, wherein the plurality of through holes are provided by press forming to form a laminated iron core. According to the configuration, the pierced relief hole can be easily formed in the laminated iron core, and can be manufactured at low cost.

According to an eighth aspect of the present invention, an electric motor handling the permanent magnet rotor according to any one of the first to seventh aspects is housed in a closed container, and the rotational force of the motor is bearing in the closed container. This is a hermetic compressor provided with a compression mechanism that is driven by a crankshaft supported by a member. According to this configuration, the motor section of the compressor can be easily assembled,
A hermetic compressor with excellent productivity can be obtained.

According to a ninth aspect of the present invention, in the hermetic compressor according to the eighth aspect, the sizes of the plurality of through holes are varied so as to correct the rotational imbalance of the compression mechanism. With the balance adjusted, according to this configuration,
We can abolish thin plates to correct imbalance,
A hermetic compressor excellent in miniaturization, reduction in the number of parts, cost reduction, and the like can be obtained.

According to a tenth aspect of the present invention, in the hermetic compressor according to the eighth or ninth aspect, the refrigerant gas for allowing the refrigerant compressed by the compression mechanism to flow from one end face to the other end face of the permanent magnet rotor. A gas path is formed, and the escape hole penetrated is made a part of the gas path. According to this structure,
There is no need to provide a through groove, which is a refrigerant passage communicating from suction to discharge, on the outer periphery of the stator of the electric motor in the hermetic compressor, and the stator can be securely fixed to the circumferential housing (body shell) in close contact. Therefore, a hermetic compressor with low noise and low vibration can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a permanent magnet rotor according to a first embodiment of the present invention.

2 is a sectional view taken along line XX of FIG. 1

FIG. 3 is a cross-sectional view showing a state in which a permanent magnet is cracked due to deformation of a laminated iron core according to Comparative Example 1.

FIG. 4 is an enlarged cross-sectional view of the permanent magnet rotor according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of the permanent magnet rotor according to the second embodiment of the present invention.

6 is a sectional view taken along line YY of FIG.

FIG. 7 is a cross-sectional view showing a state of cracking of a permanent magnet due to deformation of a laminated iron core according to Comparative Example 2.

FIG. 8 is an enlarged cross-sectional view of a permanent magnet rotor according to a second embodiment of the present invention.

FIG. 9 is an enlarged cross-sectional view of a permanent magnet rotor according to a third embodiment of the present invention.

10 is a sectional view taken along the line ZZ in FIG. 9.

FIG. 11 is a sectional view of a hermetic compressor using a permanent magnet rotor according to a third embodiment of the present invention.

FIG. 12 is a sectional view of a conventional hermetic compressor.

[Explanation of symbols]

 Reference Signs List 1 housing 2 suction port 6 stator 8 discharge port 9 laminated iron core 12 crankshaft 15 through hole 16 permanent magnet 17 nonmagnetic metal tube 18 plate 18a, 18b hole 19 caulking pin 20 escape hole

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H02K 21/14 H02K 21/14 MF term (Reference) 5H002 AA08 AB05 AB07 AC06 AE08 5H615 AA01 BB01 PP02 PP06 SS05 SS19 SS53 TT05 5H621 GA01 GA04 HH01 JK02 JK05 JK15 JK17 5H622 CA02 CA07 CA13 CB04 CB05 CB06 PP03 PP10 PP11 PP14 PP16

Claims (10)

[Claims] A through hole is provided at the center of a laminated iron core, and a relief portion is provided near the through hole in a permanent magnet rotor of an electric motor in which a crankshaft is press-fitted or shrink-fitted into the through hole. A permanent magnet rotor for a motor. 2. The permanent magnet rotor for an electric motor according to claim 1, wherein the relief portion includes a plurality of relief holes having an arc-shaped cross section surrounding the through hole. 3. The permanent magnet rotation of an electric motor according to claim 1, wherein a plurality of arc-shaped permanent magnets are arranged on the outer periphery of the laminated iron core, and the outer periphery is fixed by a non-magnetic metal tube. Child. 4. The permanent magnet rotor for an electric motor according to claim 1, wherein a plurality of arc-shaped permanent magnets are provided inside the laminated iron core. 5. The permanent magnet rotor for an electric motor according to claim 3, wherein a plurality of relief holes are arranged between the plurality of arcuate permanent magnets when viewed from a circumferential direction. 6. The permanent magnet rotor for an electric motor according to claim 4, wherein a plurality of relief holes are arranged in the same direction as the plurality of arcuate permanent magnets when viewed from a circumferential direction. 7. The iron plate according to claim 1, wherein a plurality of piercing holes are formed in the iron plate by press forming, and the iron plates are laminated to form a laminated iron core.
Or the permanent magnet rotor of the electric motor of 4 or 5 or 6. 8. A crank, wherein the motor handling the permanent magnet rotor according to claim 1 is housed in a closed container, and the rotating force of the motor is supported by a bearing member in the closed container. A hermetic compressor characterized by having a compression mechanism portion driven by being transmitted by a shaft. 9. The hermetic compressor according to claim 8, wherein the plurality of pierced relief holes are made different in size and the balance is adjusted in order to correct the rotational imbalance of the compression mechanism. 10. A refrigerant gas path for allowing the refrigerant compressed by the compression mechanism to flow from one end face to the other end face of the permanent magnet rotor, and an escape hole penetrated as a part of the gas path. Or a hermetic compressor according to 9.