JPH10281064A - Hermetic electrically driven compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetic electrically driven compressor capable of preventing a capillary tube from being clogged when alternative refrigerant and refrigerator oil are circulated through a refrigerant circuit provided with the capillary tube as an expansion mechanism. SOLUTION: An electric motor 22 is mounted on the inside of a closed case 21, and synthetic fluid, mineral oil, or refrigerator oil L composed mainly of these both fluid and oil is contained in that closed case. Also the electric motor 22 is operated so as to compress a refrigerant R composed mainly of at least one of HFC(Hydro Fl-uoro Carbon), HC(Hydro Carbon), and natural refrigerant (NH3 , CO2 ), and deliver it together with the refrigerator oil L. In addition, a laminated steel plate 40 which constitutes the stator 23 and rotor 24 of the electric motor 22 is worked using a machining fluid composed mainly of volatile HC oil and annealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hermetic electric compressor. More specifically, the present invention relates to a compressor that has a built-in electric motor and compresses and discharges refrigerant by the operation of the electric motor.

[0002]

2. Description of the Related Art FIG.
As shown in FIG. 1, the refrigerant circuit 1 of the air conditioner includes a hermetic electric compressor 2 that compresses and discharges the refrigerant, a four-way switching valve 9 that switches the direction of the flow of the refrigerant, and an outdoor heat exchanger 3. A capillary tube 4 as an expansion mechanism and an indoor heat exchanger 5
And an accumulator 8 for accumulating the refrigerant in many cases. By switching the four-way switching valve 9, during the cooling operation, the refrigerant flows in the direction of the arrow in the figure to execute the refrigeration cycle. During the heating operation, the refrigerant flows in the opposite direction.

Recently, instead of HCFC (hydrochlorofluorocarbon) which causes environmental problems, alternative refrigerants such as HFC (hydrofluorocarbon), HC (hydrocarbon) and natural refrigerant (NH ₃ , CO ₂ ) have been adopted as the above-mentioned refrigerant. Is being considered. In the refrigerant circuit, in addition to these alternative refrigerants, polyol oil as refrigeration oil,
Synthetic oils such as PAG (polyalkylene glycol) oil, polyvinyl ether oil, alkylbenzene oil, and carbonate oil are circulated.

[0004] However, process auxiliary materials (such as processing oil) used in the manufacturing process of the electric motor in the compressor 2, for example, oils remaining between the laminated steel sheets may flow out to the refrigerant circuit 1. Since such a process auxiliary material is difficult to dissolve in the above-mentioned alternative refrigerant or refrigerating machine oil, the capillary tube 4 may be clogged by the process auxiliary material.

Accordingly, an object of the present invention is to provide a hermetic electric compressor capable of preventing clogging of a capillary tube when circulating an alternative refrigerant and refrigerating machine oil in a refrigerant circuit having a capillary tube as an expansion mechanism. It is in.

[0006]

According to a first aspect of the present invention, there is provided a hermetic motor-driven compressor in which a motor is mounted in a closed case and a refrigerating machine oil mainly composed of synthetic oil is accommodated. A hermetic electric compressor that operates the electric motor to compress a refrigerant containing at least one of hydrofluorocarbon, hydrocarbon, and natural refrigerant as a main component and discharges the refrigerant together with the refrigerating machine oil; Is characterized by being processed using a processing oil containing volatile hydrocarbon oil as a main component and annealed.

[0007] In the hermetic compressor according to the first aspect, the laminated steel sheets constituting the stator and the rotor of the electric motor are processed with a processing oil containing volatile hydrocarbon oil as a main component and annealed. The use of a volatile hydrocarbon oil reduces the molecular weight, and the annealing further reduces the molecular weight. As a result, most of the refrigerant does not remain, but assuming that a small amount remains, when the refrigerant and the refrigerating machine oil are circulated through a refrigerant circuit having a capillary tube as an expansion mechanism, a low molecular weight is obtained even if the residue flows out. It was confirmed that the capillary tube was not clogged.

In the hermetic electric compressor according to the present invention, the electric motor is mounted in a closed case, and a refrigerating machine oil containing synthetic oil as a main component is accommodated. In a hermetic electric compressor that compresses a refrigerant mainly containing at least one of natural refrigerants and discharges the refrigerant together with the refrigerating machine oil, an interlayer insulating material that electrically insulates between coil layers of the electric motor includes an oligomer. It is characterized by comprising a low oligomer type polyethylene terephthalate film whose content is set to 1.0% by weight or less.

In the hermetic electric compressor according to the second aspect, the interlayer insulating material for electrically insulating between the coil layers of the electric motor includes:
Since the oligomer content is made of a low oligomer type polyethylene terephthalate film set to 1.0% by weight or less, when circulating the refrigerant and the refrigerating machine oil in a refrigerant circuit including a capillary tube as an expansion mechanism,
The oligomer is less likely to flow into the refrigerant circuit than when the interlayer insulating material is made of ordinary polyethylene terephthalate. As a result, clogging of the capillary tube is prevented. The oligomer that has flowed out is hydrolyzed by water in the refrigerant circuit, reacts with the metal, and produces a metal soap. This is one of the causes of clogging of the capillary tube. In particular, the oligomer content of the polyethylene terephthalate film constituting the interlayer insulating material is set to 1.0.
It was found that by setting the weight% or less, clogging of the capillary tube did not actually occur for a long period of time. On the other hand, when the oligomer content exceeded 1.0% by weight, clogging of the capillary tube was observed due to long-term use.

The term "low oligomer type polyethylene terephthalate" as used herein means a type in which the oligomer content is reduced as compared with the oligomer content of general polyethylene terephthalate (1.90% by weight).

In general, when the structural unit is represented by M and the polymer (polymer) is represented by (M) _n , a polymer having n not so large is referred to as an “oligomer”. , N = 2 to 5 are called “oligomer”. That is, in this specification,
"Oligomer" refers to diethylene terephthalate, triethylene terephthalate, tetraethylene terephthalate and pentaethylene terephthalate.

[0012]

Embodiments of the present invention will be described below in detail.

FIG. 1A shows a longitudinal section of a hermetic electric compressor 20 according to an embodiment of the present invention. This hermetic electric compressor 20 is adapted to be applied to a refrigerant circuit 1 having a capillary tube 4 as shown in FIG.
As the refrigerant circulated through the refrigerant circuit 1, an alternative refrigerant R mainly containing at least one of HFC (hydrofluorocarbon), HC (hydrocarbon) and natural refrigerant (NH ₃ , CO ₂ ) is employed. Shall be.

As shown in FIG. 1 (a), the hermetic electric compressor 20 includes a substantially cylindrical hermetic case 21.
A discharge pipe 2 is provided on a lid 21a for closing the upper part of the closed case 21.
9. A suction pipe 2 is provided below the cylindrical portion 21c of the closed case 21.
8 are provided through each. Sealed case 21
The bottom 21b is provided with a mounting foot 30 for mounting the closed case 21 to the outside.

An electric motor 22 is provided inside the sealed case 21.
A cylinder 26 is arranged. The electric motor 22 includes a stator 23 annularly mounted along the inner periphery of the upper part of the closed case 21, and a rotor 24 arranged inside the stator 23 with a slight gap. Rotor 2
4 is integrally provided with a crankshaft 25 extending vertically through its center.

As shown in FIG. 2, the stator 23 includes a laminated steel plate 40 having a plurality of slots 49, 49,.
, And a plurality of coils 41, 42, 43,... The laminated steel sheet 40 is annealed after forming in order to remove process auxiliary materials used in the manufacturing process. The coil sides of the adjacent coils 41, 42, 43,.
. 0 are inserted into the slots 49, 49,. Specifically, as illustrated in FIG. 3, a coil 41 formed of a bundle of a polyamideimide / polyesterimide-coated copper wire 48 wrapped in a semi-closed slot 49 by a polyester film 51 as an interlayer insulating material; A coil 42 composed of a bundle of a polyamideimide / polyesterimide-coated copper wire 48 wrapped with a polyester film 52 as an interlayer insulating material is inserted, and further inserted with the entire circumference wrapped with a polyester film 50. ing. In order to prevent the coils 41 and 42 from coming off, a wedge 60 made of polyester is
Is inserted. The polyester films 51, 52 and 50, and the polyester wedge 60 are all of low oligomer type in which the oligomer content is reduced to 1.0% by weight or less (in general polyester, the oligomer is about 1.90% by weight). include). Further, when knitting the polyester fiber for the tying string or the lead wire insulating tube, a surfactant is applied to the polyester fiber for antistatic. After the coating is completed and before assembly, the surfactant is removed from the polyester fiber by washing with hot water.

Although not shown for simplicity, the rotor 24 has a laminated steel plate having a plurality of slots, like the stator 23. The material of the laminated steel plate of the rotor 24 is the same as that of the stator 23, and is treated similarly.

As shown in FIG. 1A, the cylinder 26 is disposed below the electric motor 22, and a roller (rotating piston) 27 is provided inside the cylinder 26. The roller 27 is connected to a crank pin portion 25a formed on the lower end side of the crank shaft 25. FIG.
As can be seen from (b) (showing the cylinder 26 in a plan view), when the electric motor 22 is operated to rotate the crankshaft 25, the movement of the crankpin portion 25a causes the roller 27 to move through the cylinder 26 in the cylinder. And rotates eccentrically from the center O. Thereby, the refrigerant gas R can be sucked from the suction port 33 through the suction pipe 28 and sent out from the discharge port 34 to the discharge pipe 29 while compressing the refrigerant gas R. The vane 31 is urged by a spring 32 and always contacts the roller 27 to partition the suction side and the discharge side in the cylinder 26. This prevents the compressed refrigerant gas R from returning to the suction side. A discharge valve (not shown) is provided at the discharge port, and the discharge valve is opened only when the pressure of the refrigerant gas R in the cylinder 26 becomes higher than the pressure of the already discharged gas. This discharge valve can prevent backflow of the discharge gas.

As shown in FIG. 1A, a refrigerating machine oil L is stored inside a bottom 21b of the closed case 21. The refrigerating machine oil L contains at least one of synthetic oils such as polyol ester oil, PAG (polyalkylene glycol) oil, polyvinyl ether oil, alkylbenzene oil, and carbonate oil. A refrigerant to be compressed and discharged by the compressor 20 to the refrigerating machine oil L;
That is, HFC (hydrofluorocarbon), HC
(Hydrocarbon) and an alternative refrigerant R containing at least one of natural refrigerants (NH ₃ and CO ₂ ) as a main component. The refrigerating machine oil L is supplied to the bearing portion through the pipe line 35, leaks from the upper bearing portion, and is sent out to the discharge port 34 together with the compressed refrigerant gas R. Therefore, the refrigerating machine oil L circulates in the refrigerant circuit 1 together with the refrigerant R.

In the hermetic electric compressor 20, the laminated steel plate 40 constituting the stator 23 and the rotor 24 of the mounted electric motor 22 is processed using a processing oil mainly composed of volatile hydrocarbon oil, and is annealed. So the laminated steel plate 4
Almost no residue between 0. When the refrigerant R and the refrigerating machine oil L are circulated through the refrigerant circuit 1 including the capillary tube 4 as an expansion mechanism, a small amount of processing oil
Even if it flows out from the refrigerant circuit 2 into the refrigerant circuit 1, the processing oil has a low molecular weight because volatile processing oil is used or has been annealed, so that clogging of the capillary tube 4 does not occur. Moreover, the low-oligomer type polyethylene is used as an interlayer insulating material 51, 52 for electrically insulating between the coil layers 41, 42, 43 and an insulating material 50 for insulating between the coil layers 41, 42, 43 and the laminated steel plate 40. Since it is made of a terephthalate film, the oligomer is less likely to flow out to the refrigerant circuit 1 than when the insulating material is made of ordinary polyethylene terephthalate. In particular, it was found that by setting the oligomer content of the polyethylene terephthalate film to 1.0% by weight or less, clogging of the capillary tube did not actually occur for a long period of time. On the other hand, when the oligomer content exceeded 1.0% by weight, clogging of the capillary tube was observed due to long-term use. As a result, clogging of the capillary tube 4 could be effectively prevented.

Further, since the surfactant has already been removed from the polyester fiber of the tying string or the lead wire insulating tube before assembly, the surfactant does not flow out to the refrigerant circuit 1 from this polyester fiber. Thereby, the clogging of the capillary tube 4 could be prevented more effectively.

In this embodiment, the compressor 20 is of a rotary type, but it is needless to say that the present invention is not limited to this. The present invention can be widely applied to other types of compressors such as a scroll type.

[0023]

As is apparent from the above description, in the hermetic electric compressor of the first aspect, the laminated steel sheets constituting the stator and the rotor of the electric motor use a processing oil mainly composed of volatile hydrocarbon oil. Since it is processed and annealed, it hardly remains between the laminated steel sheets. When circulating the substitute refrigerant and the refrigerating machine oil in the refrigerant circuit having a capillary tube as an expansion mechanism, use a volatile processing oil even if a small amount of the remaining processing oil flows out of the electric motor into the refrigerant circuit. Since the processing oil has been annealed, the processing oil has a low molecular weight and does not cause clogging of the capillary tube.

In the hermetic electric compressor according to the second aspect, the interlayer insulating material for electrically insulating between the coil layers of the electric motor is a low oligomer type polyethylene terephthalate having an oligomer content of 1.0% by weight or less. When the alternative refrigerant and the refrigerating machine oil are circulated through the refrigerant circuit having the capillary tube as the expansion mechanism, the oligomer is transferred to the refrigerant circuit as compared with the case where the interlayer insulating material is made of ordinary polyethylene terephthalate. It becomes difficult to flow out. As a result, clogging of the capillary tube can be prevented. In particular, it was found that by setting the oligomer content of the polyethylene terephthalate film constituting the interlayer insulating material to 1.0% by weight or less, clogging of the capillary tube did not actually occur for a long period of time. In contrast, the oligomer content is 1.
When the content exceeds 0% by weight, clogging of the capillary tube was recognized due to long-term use.

[Brief description of the drawings]

FIG. 1 is a view showing a longitudinal section of a hermetic electric compressor according to an embodiment of the present invention.

FIG. 2 is a view showing a stator constituting an electric motor of the hermetic electric compressor.

FIG. 3 is a view showing a cross section of a slot portion of the stator.

FIG. 4 is a diagram illustrating a refrigerant circuit of the air conditioner.

[Explanation of symbols]

Reference Signs List 20 hermetic electric compressor 22 electric motor 23 stator 24 rotor 40 laminated steel plate 49 slot 41, 42, 43 coil 50, 51, 52 low oligomer type polyester film

Claims (2)

[Claims] 1. An electric motor (22) in a closed case (21).
And a refrigerating machine oil (L) containing a synthetic oil as a main component, and operating the electric motor (22) to operate a refrigerant containing at least one of a hydrofluorocarbon, a hydrocarbon, and a natural refrigerant ( R), and in the hermetic electric compressor (20) discharging together with the refrigerating machine oil (L), the laminated steel plate (40) constituting the stator (23) and the rotor (24) of the electric motor (22) is volatilized. A hermetic compressor characterized by being processed and annealed using a processing oil mainly composed of a hydrophobic hydrocarbon oil. 2. An electric motor (22) in a sealed case (21).
And a refrigerating machine oil (L) containing a synthetic oil as a main component, and operating the electric motor (22) to operate a refrigerant containing at least one of a hydrofluorocarbon, a hydrocarbon, and a natural refrigerant ( R), in a hermetic electric compressor (20) for discharging together with the refrigerating machine oil (L), an interlayer insulation for electrically insulating between coil layers (41, 42, 43) of the electric motor (22). A hermetic electric compressor, wherein the material comprises a low oligomer type polyethylene terephthalate film (51, 52) having an oligomer content of 1.0% by weight or less.