JPH0279753A - Magnet type rotor - Google Patents

Abstract

PURPOSE:To lower vibrations and noises, and to improve energy efficiency by heating pressing-injecting a crystalline thermoplastic resin having a glass transition temperature of 40 deg.C or more into the clearances of a permanent magnet, an adjacent permanent magnet, a yoke, an end-section protective member and an outer-circumference protective member and cooling and solidifying the thermoplastic resin. CONSTITUTION:Yokes 1, to which hole sections into which cylindrical members 8 can be penetrated are formed previously, are constituted cylindrically by a magnetic substance such as iron, and a plurality of magnets 2 are arranged cylindrically on the outer circumferential sections of the yokes 1. Cylindrical external protective members 3 are fitted, end-section protective members 4a are installed at both ends in the axial direction, and the cylindrical members 8 are engaged into the end-section protective members 4a and the hole sections of the yokes 3. A crystalline thermoplastic resin such as polyphenylene sulfide having a glass transition temperature of 40 deg.C or more is heated and pressure- injected from the detente holes 10 combining filler holes of the end-section protective members 4a, and a rotor constitutional member is fixed mechanically and cooled, thus completing a rotor.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rotor, and in particular to a rotor that is driven by power supplied through a control device such as an inverter, and whose rotation range ranges from low speed to high speed, e.g. The present invention relates to a permanent magnet rotor for a brushless motor suitable for hermetic electric compressors and the like.

[Conventional technology]

A conventional permanent magnet rotor (hereinafter referred to as a single rotor) has a cylindrical structure made of a magnetic material such as iron, as shown in Figures 5 and 6. A plurality of C-shaped permanent magnets (hereinafter simply referred to as magnets) 2 are fixed with adhesive or the like and arranged in a cylindrical shape so that predetermined magnetic poles are formed on the outer periphery of a yoke 1. Ferrite magnets are commonly used as the material for the magnet 2, but this ferrite magnet has the disadvantage of being weak in mechanical strength, so it is difficult to prevent damage and scattering due to centrifugal force during high-speed rotation. For this purpose, an outer circumferential protection member 3 made of glass fiber-reinforced thermosetting resin, stainless steel pipe, or the like is provided on the outer circumference of the magnet 2.

On the other hand, in closed-type 'Ili dynamic compressors, contamination of foreign matter will impair the reliability of the sliding parts, so small cracks that occur inside the magnets during the manufacture of the magnets or rotor may cause centrifugal force during rotation. Alternatively, end protection members 4 are provided at both ends of the rotor in the axial direction in order to prevent the magnets from being damaged by vibration or the like and minute pieces of the damaged magnets being scattered within the compression i1. This end protection member 4 is die-cast from a low melting point metal such as aluminum or zinc, and is held at both ends of the rotor in the axial direction by a plurality of connecting portions 6 passing through the inside of the yoke 1.

Intelligence [P that invention tries to solve! u Problem] In the rotor constructed by the above-mentioned conventional technology, the magnet 2 and the outer circumferential protection member 3
is set in the mold of a die-casting machine to form the end protection member 4. When die-casting a low melting point metal (e.g. zinc), heat shock of about 400°C and high injection pressure (e.g. 700-/CfI) are produced. ), the magnet 2 undergoes rapid thermal strain, causing cracks 13 in the magnet 2 as shown in FIG. 7, leading to breakage and creating a void.

Casting defects such as unfilled areas and cavities cause mass imbalance, which causes vibrations during high-speed rotation.

If the density of the filling metal is high, the amount of unbalance will further increase and the performance as a rotating body will deteriorate. Further, finishing work was required to prevent deformation 3a of the outer circumferential protection member and protrusion of zinc.

When the rotor is completely filled with zinc, an induced current is generated in the conductive zinc filled between the magnets, which acts as a stray loss and reduces motor efficiency by 2 to 5%.

On the other hand, in the method of mechanically fastening the magnet 2 to the separate end protection member 4 using a connecting rod, the rotor dimensions are designed taking into account variations in the axial length of the ferrite magnets. In some cases, a fairly large gap is created between the uaKm material 4 and the magnet 2.

For this reason, a gap filler is provided in this portion to reinforce the protection of the end of the magnet 2. If this gap filler is constructed by filling and curing a thermosetting resin,
Increased rotor assembly man-hours, reaction by-products and unreacted materials from thermosetting resins may cause refrigerant, refrigeration oil,
There were problems such as increased influence on insulating materials.

[Means to solve the problem]

The above purpose is to utilize the protrusion provided on the yoke to guide the placement of the magnet, the magnet, the yoke, the end protection member, and the outer periphery protection member, and to use the above-mentioned components as a rod passing through the yoke and the end protection member and its tip. After setting in the specified position using the mechanical fastening method of crimping, the melt viscosity is arbitrarily adjusted through the resin injection port provided in the end protection member, and the melt viscosity is adjusted at a low temperature (for example, 2
00~350℃), low pressure (e.g. 300Kfr/cn
l) can be charged with jjjj and has the feature of low density non-conductivity,
In addition, it has excellent glass transition temperature 4 and is resistant to fluorocarbon refrigerator oil.
This can be achieved by creating a structure in which the crystalline thermoplastic resin having a temperature of 0° C. or higher can be injected all at once and fixed together.

The filler in the injection port also serves as a mechanical fastener to prevent displacement due to the rotational movement of the rotor.

[Effect]

The crystalline thermoplastic resin filled with a glass transition temperature of 40°C or higher has attack resistance, such as a decrease in strength, and
It is resistant to swelling, dissolution, stress cracking, and extraction of low-molecular substances, and it is possible to mix inorganic fillers arbitrarily, select an appropriate melt viscosity, and fill at low temperature and pressure.
The unbalance of the rotating body can be greatly improved by preventing damage to the magnet due to heat shock and by making it easier to deform and fill the outer periphery protection member. In addition, since the density is lower than that of aluminum or zinc filled metals, even if there are minute filling defects, dynamic balance characteristics can be suppressed to a minimum, reducing vibration and improving rotational response due to weight reduction. .

The crystalline thermoplastic resin is injected through the injection port provided in the edge protection member with the yoke, magnet, outer circumference protection member, and edge protection member set in the mold in advance, and then simply cooled and solidified. , each part can be filled and fixed together at the same time.

Unlike thermosetting resins, this embodiment has excellent productivity because it does not require complicated assembly operations such as a heat curing process, removal of protruding filler material, and fastening process to the outer periphery protection member. In addition, since thermosetting resins involve a heat curing reaction, reaction by-products and unreacted residues are eluted into the refrigerant refrigeration oil and precipitate in the compressor and refrigerant piping system, causing flow path blockage and refrigerant damage. Although there is a concern that the resin may accelerate the deterioration of properties of refrigeration oil and electrical insulators, the resin of the present invention does not suffer from such elution problems.

When it was incorporated into the inverter-controlled motor manufactured in this way and its performance was observed, it was confirmed that the effect of filling with non-conductive resin reduced stray loss and significantly improved motor efficiency.

The crystalline thermoplastic resin that can be used here has a glass transition temperature of 40°C or higher, and since the compressor is operating normally, it works to suppress the intrusion of fluorocarbons and refrigeration oil into the molecules, so it does not melt or melt. Deterioration phenomena such as swelling and decrease in mechanical strength do not occur.

A crystalline thermoplastic resin with a glass transition temperature of 40°C or higher is
Targets resins such as polyamide (nylon 6, nylon 66, etc.), polyphenylene 4 #7 ide, polybutylene terephthalate, polyethylene terephthalate, polyether ether ketone, aromatic polyester, polyethylene naphthalate, polyamideimide, etc.
Glass fibers and inorganic fillers can be blended in any range to adjust the necessary melt viscosity and fluidity of the resin. t(i) It is possible to aim for stronger strength.

As mentioned above, when the permanent magnet rotor of the present invention is incorporated into a brushless motor of a high-speed, especially inverter-controlled hermetic electric compressor, it has the advantage of reducing vibration and improving motor efficiency by 2 to 596 points.

Therefore, when a refrigeration system is constructed using the above-mentioned hermetic electric compressor, vibration and noise can be reduced, and energy efficiency can be improved by 2 to 596 points. The refrigeration equipment here refers to room conditioners, refrigerators, dehumidifiers, showcases,
This applies to large air conditioners, etc.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in Fig. 1, Fig. 2, and Fig. 2. It is connected to the stopper hole 10 and has a predetermined width in the radial direction so that the axial end of the magnet 2 serves as an insertable portion and a resin flow path. Reference numeral 8 denotes a plurality of rod-like members that penetrate the end protection member 4m and the inside of the yoke 1 in the axial direction, and the ends 9 that protrude toward both ends in the axial direction are fastened by screws, crimping, etc. The outer circumferential protection member 4a is held at both ends of the rotor in the axial direction with the outer circumferential protection member 3 sandwiched therebetween.

Next, the method of constructing the rotor shown in FIG. 2 will be explained. A yoke 1 is made of a magnetic material such as iron and has a cylindrical shape, in which a hole through which a rod-shaped member 8 can pass is provided in advance, and the outer circumference of this yoke 1 is A plurality of magnets 2 are formed on the yoke 1 so as to form a predetermined magnetic pole. Using the protrusion 1a shown in the detailed view of FIG. 3 as a guide, the magnets 2 are arranged in a cylindrical shape with an appropriate gap. After that, the cylindrical external protection member 3 is inserted and the rod-shaped member 8 is inserted in advance.
At this time, if the end of the magnet 2 protrudes from the axial end of the yoke 1, the protruding part is inserted into the recess 7. Insert. Then, the rod-shaped member 8 is attached to the end protection member 4a and the yoke 1.
At the same time, the protruding end 9 is fitted with an appropriate fastening process such as screwing or caulking, and the end protection member 4a, yoke 1, and outer periphery protection member 3 are fixed in a sandwiched state. A crystalline thermoplastic resin having a glass transition temperature of 40°C or higher, such as polyphenylene sulfide, is heated to 250 to 350°C through the injection port and rotation stopper hole 10 of the protection member 4a.
Approximately 300Ke/cn! The magnets 2, the lattice-like channels 12 of the adjacent magnets 2, and the stepped annular channels 7a provided in the recesses 7 of the end protection member are integrally filled, and the rotor components are machined. After fixing, the rotor is completed by cooling. At this time, if the temperature of the rotor components is preheated to 150°C or higher, the fluidity and filling of the resin will be improved and crystallization will be promoted, resulting in significant improvements in fluorocarbon resistance, resistance to refrigerator oil, and mechanical strength. did it.

The rotor manufactured by the above method of the present invention has extremely good dynamic balance characteristics, little vibration, and a motor efficiency of 2 to 2.
It was confirmed through actual measurement that the improvement was achieved by 596 points.

Next, regarding the type of resin to be filled, we immersed various resins in a coexisting liquid of Freon 22 and naphthenic refrigeration oil in which a hermetic compressor was operated at 150°C for 7 days, and measured the changes in resin properties. The relationships between (Examples 1 to 9) and the properties of the test resins (Comparative Examples 1 to 6) are shown in Tables 1 and 2.

According to the results, as shown in Examples 1 to 5 and Examples 7 to 8, crystalline resins such as polyamide (nylon 6, nylon 66), polyphenylene sulfide, polybutylene terephthalate, polyethylene terephthalate, polyether ether ketone, polyethylene naphthalate, etc. It has been found that a material with a glass transition temperature of 40° C. or higher is most suitable as a filler because it has very little strength reduction, swelling and dissolution, cracking, and dissolved extractables. On the other hand, the polyacetal with a low glass transition temperature of Example 6 and the non-quality polyphenylene oxide, polycarbonate, polysulfone, polyether sulfone, polyetherimide, and polyarylate shown in Comparative Examples 1 to 6 were swollen and dissolved. It was confirmed that the rotor was impractical due to a significant decrease in the phenomenon and strength properties.Therefore, the rotor filled with and fixed with the crystalline thermosetting resin with a glass transition temperature of 40°C or higher cannot be used in a hermetic compressor. It was found that it has sufficient practical performance in the usage environment of Freon 22.Also, the attack on the esterimide enamel wire and polynyster film that coexisted in this test was small and did not pose a problem.Similarly, Freon 22 No deterioration and muddying phenomena such as decomposition of naphthenic oil or promotion of carbonization of naphthenic refrigeration oil were observed.

〔Effect of the invention〕

According to the present invention, the fixing assembly of the yoke, end protection member, magnet, and outer periphery protection member can be easily performed by injection molding of molten resin, so that the productivity of the rotor is improved and economical effects can be expected. Since the low-density resin is completely filled, the performance of the rotating body is improved, such as vibrations caused by the unbalanced characteristics of the rotating body's mass, and rotational response due to weight reduction, and the filling is made of a non-conductive material. Therefore, it has the effect of reducing stray loss due to induced current generated in the rotor when used as a motor assembly, and has the effect of improving motor efficiency by 2 to 596 points compared to aluminum die-cast filling. In addition, the filled resin has sufficient strength and resistance to fluorocarbons and refrigerating machine oil even in the operating environment of the compressor, so it can be used as a ferrite magnet rotor for the motor of a hermetic electric compressor that uses fluorocarbons. It has high reliability and has a significant effect on improving rotor performance, especially in applications where the rotation speed is high due to inverter control. Therefore, low vibration, low noise, and improvement in energy efficiency of 2 to 596 can be expected in hermetic electric compressors and refrigeration systems using the same.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional plan view of an embodiment of the present invention, Fig. 2 is a partial cross-sectional front view, Fig. 3 is a detailed view of section A in Fig. 1, and Fig. 4 is a detailed view of section B in Fig. 1. It is. FIG. 5 is a partial cross-sectional plan view of a conventional general ferrite magnet type rotor, FIG. 6 is a cross-sectional view of the front part, and FIG. 7 is a detailed view of section C in FIG. 6.

Claims (1)

[Claims] 1. In a rotor in which divided permanent magnets are arranged on the outer circumference of a cylindrical yoke, a cylindrical outer circumference protection member is further fitted and the protection members are provided at both ends in the axial direction, A crystalline thermoplastic resin having a glass transition temperature of 40° C. or higher is injected under heat and pressure into the gap between the permanent magnet and the adjacent permanent magnet, yoke, end protection member, and outer circumference protection member, and then cooled and solidified to form the component member. A magnetic rotor with a structure that fixes and mechanically fastens the rotor. 2. Claims characterized in that polyamide, polyphenylene sulfide, polybutylene terephthalate, polyethylene terephthalate, polyether ether ketone, aromatic polyester, polyethylene naphthalate, polyamideimide, etc. are used as the crystalline thermoplastic resin. The rotor according to item 1. 3. A hermetic electric compressor using the rotor according to claim 1. 4. A refrigeration system using the hermetic electric compressor according to claim 3.