JP5990765B2 - Refrigerant compressor - Google Patents

Description

  The present invention relates to a refrigerant compressor used for a refrigerator, an air conditioner and the like.

  Conventionally, as this kind of refrigerant compressor, development of a high-efficiency refrigerant compressor that reduces the use of fossil fuels from the viewpoint of protecting the global environment has been promoted, and in particular, the viscosity of the lubricant is reduced. Refrigerant compressors that use many polymer materials while reducing sliding loss are known (see, for example, Patent Documents 1, 2, 3, and 4).

  Hereinafter, the conventional refrigerant compressor will be described with reference to the drawings.

  FIG. 4 is a cross-sectional view of a prior art hermetic electric refrigerant compressor. FIG. 5 is an enlarged view of a portion B of FIG. 4 in the compressor.

  In the sealed container 2, an electric element 8 formed by a stator 4 and a rotor 6 made of a winding 5 and insulating paper 7, and a compression element 10 driven to rotate by the electric element 8 are stored, respectively. In addition, lubricating oil 12 having a viscosity of VG3 to VG10 is stored at the bottom.

  The electric element 8 and the compression element 10 are integrally assembled to constitute a compression mechanism 14, and the compression mechanism 14 is elastically supported in the sealed container 2 by a plurality of coil springs 16.

  The compression element 10 includes a shaft 26 having an eccentric shaft portion 24 formed through a main shaft portion 20 and a flange portion 22, a cylinder block 32 forming a compression chamber 30, and a shaft block 32 provided in the cylinder block 32 to support the shaft 26. Main bearing 34. Further, the compression element 10 includes a piston 36 that reciprocates in the compression chamber 30, and a connection mechanism 38 that connects the piston 36 and the eccentric shaft portion 24.

  Further, the compression element 10 is provided at the lower portion 39 of the flange portion 22 of the shaft 26, the upper race seating surface 42 provided substantially at right angles to the axis 40 a of the main shaft portion 20, and the main bearing 34 above the main bearing 34. And a thrust sliding portion 44 that supports the load in the gravity direction of the shaft 26 and the rotor 6, and is provided between the upper race seating surface 42 and the thrust sliding portion 44. A thrust ball bearing 46 is provided to form a reciprocating hermetic compressor.

  The suction tube 21 is fixed to the sealed container 2 and connected to the low pressure side (not shown) of the refrigeration cycle, and guides a refrigerant gas (not shown) into the sealed container 2. The suction muffler 23 is sandwiched between the valve plate 25 and the head 27.

  The shaft 26 supplies an oil supply mechanism 50 having one end communicating with the lubricating oil 12 stored in the sealed container 2, and a part of the lubricating oil 12 pumped up by the oil supply mechanism 50 to the thrust sliding portion 44. An oil supply groove 52 is provided.

  The electric element 8 includes a stator 4 fixed below the cylinder block 32 and a rotor 6 fixed to the main shaft portion 20 by shrink fitting.

The thrust ball bearing 46 includes a plurality of balls 60, a holder portion 62 that holds the balls 60, and an upper race 64 and a lower race 66 that are respectively disposed above and below the ball 60. The upper race 64 is in contact with the upper race seating surface 42 of the collar portion 22, and the lower race 66 is in contact with the thrust sliding portion 44.

  The operation of the hermetic compressor configured as described above will be described below.

  When the electric element 8 is energized from an external power source (not shown), the rotor 6 rotates and the shaft 26 rotates accordingly. Then, the turning motion of the eccentric shaft portion 24 is converted into a reciprocating motion via the connecting mechanism 38 and transmitted to the piston 36. As a result, the piston 36 reciprocates in the compression chamber 30, and the compression element 10 performs a predetermined compression operation.

  By this operation, the refrigerant gas is sucked into the compression chamber 30 from the cooling system (not shown), compressed, and then discharged again to the cooling system.

  At this time, the oil supply mechanism 50 of the shaft 26 draws up the lubricating oil 12 and lubricates each sliding portion (not shown). A part of the lubricating oil 12 is supplied from the oil supply groove 52 to the thrust sliding portion 44 to lubricate the thrust ball bearing 46.

  The weight of the shaft 26 and the rotor 6 is supported by a thrust ball bearing 46, and the ball 60 rolls between the upper race 64 and the lower race 66 when the shaft 26 rotates. As a result, the torque for rotating the shaft 26 is smaller than that of the thrust slide bearing. Therefore, the loss in the thrust bearing can be reduced and the input can be reduced, so that the compression operation can be performed with high efficiency.

  The material of the insulating paper 7 is polyethylene terephthalate (PET), the material of the suction muffler 23 is polybutylene terephthalate (PBT), and the holder portion 62 is polyamide (PA). Furthermore, polybutylene terephthalate (PBT) and polyphenylene sulfide (PPS) are used as insulating members in the inverter motor.

JP 10-339289 A JP 2003-105099 A JP 2007-292018 A JP 2009-221872 A

  However, in the conventional polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyphenylene sulfide (PPS), the content of oligomers contained in each polymer material is regulated. When all the oligomers to be extracted are extracted, there is a problem that the capillaries constituting the cooling system are clogged.

  In particular, in recent years, as the viscosity of lubricating oils has decreased, the speed of oligomer extraction from polymer materials has increased, and in addition, a thrust ball bearing using a polyamide (PA) material as a ball cage for higher efficiency. Since the total amount of oligomers in the compressor is increased, there is a problem that the possibility that the capillary is blocked increases.

  This invention solves the said conventional subject, The viscosity of lubricating oil is made into the total amount of the cyclic oligomer of the dimer-pentamer contained in the polymeric material used for a compressor by 500 mg or less. It is an object of the present invention to provide a highly efficient and highly reliable refrigerant compressor even if the number of parts is reduced or the number of parts of the polymer material is increased.

The refrigerant compressor of the present invention stores in a hermetically sealed container a lubricating oil having a viscosity of VG3 to VG10, one of ester oil, polyvinyl ether, polyalkylene glycol, or a mixture thereof, and an electric element. A compression element that is driven by the electric element and compresses a mixture mainly composed of R134a and R134a, or a refrigerant mainly composed of R1234yf or R1234yf, and constitutes the electric element and the compression element At least one member is a polymer material, and the total amount of dimer to pentamer cyclic oligomers contained in the polymer is 500 mg or less.

  This prevents the capillaries of the system from being clogged even if the viscosity of the lubricating oil is reduced or the number of parts of the polymer material is increased, improving the efficiency of the refrigerant compressor and improving the reliability. Improvements can be made.

The refrigerant compressor of the present invention stores lubricating oil as ester oil, polyvinyl ether, polyalkylene glycol having a viscosity of VG3 to VG10, or a mixture thereof. At least one member constituting the electric element and the compression element is housed by containing a compression element that is driven and compresses a mixture mainly composed of R134a and R134a, or a refrigerant mainly composed of R1234yf or R1234yf. Even if the viscosity of the lubricating oil is lowered by making the total amount of the dimer to pentamer cyclic oligomer contained in the polymer 500 mg or less, the component of the polymer material Even if it is increased, the capillaries of the system are prevented from becoming clogged, and the refrigerant is highly efficient and reliable. It is possible to provide a compressor.

Sectional drawing of the refrigerant compressor in Embodiment 1 of this invention. The enlarged view of the A section of FIG. 1 in the same refrigerant compressor Explanatory diagram showing the relationship between oligomer amount and capillary blockage Sectional view of a refrigerant compressor showing a conventional example Enlarged view of part B of FIG. 4 in the same compressor

According to the first aspect of the present invention, the lubricating oil is stored in an airtight container as ester oil having a viscosity of VG3 to VG10 , polyvinyl ether, polyalkylene glycol, or a mixture thereof. And a compression element that is driven by the electric element and compresses a refrigerant composed mainly of R134a, R134a, or a mixture mainly composed of R1234yf or R1234yf, and constitutes the electric element and the compression element The at least one member is a polymer material, and the total amount of the dimer to pentamer cyclic oligomer contained in the polymer is 500 mg or less.

Such things, the viscosity of the lubricating oil, even as the range of VG3～VG 10, to prevent the capillary system is closed, it is possible to improve the reliability of the system and compressor.

  The invention according to claim 2 is the invention according to claim 1, wherein the polymer material is at least one of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyamide (PA) and polyphenylene sulfide (PPS). It is one thing.

  As a result, even if all oligomers are extracted from individual polymer materials, the capillaries of the system are prevented from being blocked, and the reliability is improved.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the compression element includes a rotor and a thrust bearing portion that supports a weight of a shaft connected to the rotor, and the thrust bearing portion Is configured to include a thrust ball bearing, the bearing function of the thrust ball bearing can be maintained, and the reliability of the compressor can be maintained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
1 is a cross-sectional view of a refrigerant compressor according to Embodiment 1 of the present invention. FIG. 2 is an enlarged view of a portion A in FIG. 1 in the refrigerant compressor. FIG. 3 is an explanatory diagram showing the relationship between the oligomer amount and the capillary blockage.

  1 and 2, the hermetic container 102 accommodates an electric element 108 composed of a stator 104 and a rotor 106, and a compression element 110 that is rotationally driven by the electric element 108. Stores mineral oil having a viscosity of VG3 to VG10 as the lubricating oil 112. The electric element 108 and the compression element 110 are assembled together to form a compression mechanism 114. The compression mechanism 114 is elastically supported in the sealed container 102 by a plurality of coil springs 116.

  The compression element 110 includes a shaft 126 having an eccentric shaft portion 124 formed via a main shaft portion 120 and a flange portion 122, a cylinder block 132 that forms a compression chamber 130, a cylinder block 132, and the shaft 126. And a main bearing 134 to be supported. Further, the compression element 110 includes a piston 136 that reciprocates in the compression chamber 130, and a connection mechanism 138 that connects the piston 136 and the eccentric shaft portion 124. The compression element 110 is provided at a lower portion 139 of the flange portion 122 of the shaft 126, and an upper race seating surface 142 provided substantially perpendicular to the axis 140 a of the main shaft portion 120, and an upper portion of the main bearing 134. A thrust sliding portion 144 that is provided at a substantially right angle to the shaft center 140 b of 134 and supports the load in the gravity direction of the shaft 126 and the rotor 106, and is provided between the upper race seating surface 142 and the thrust sliding portion 144. A thrust ball bearing 146 is provided to form a reciprocating hermetic compressor.

The suction tube 121 is fixed to the sealed container 102 and connected to the low pressure side (not shown) of the cooling system, and guides a refrigerant gas (not shown) into the sealed container 102. The suction muffler 123 is sandwiched between the valve plate 125 and the head 127.

  One end of the shaft 126 is immersed in the lubricating oil 112 stored in the sealed container 102 so that the lubricating oil 112 can be pumped up, and a part of the lubricating oil 112 pumped up by the lubricating mechanism 150 is converted into a main shaft portion. An oil supply groove 152 is provided to supply 120 thrust sliding portions 144.

  The electric element 108 includes a stator 104 fixed below the cylinder block 132 and a rotor 106 fixed to the main shaft portion 120 by shrink fitting.

  The thrust ball bearing 146 includes a plurality of balls 160, a holder portion 162 that holds the balls 160, and an upper race 164 and a lower race 166 that are respectively disposed above and below the ball 160. The upper race 164 is in contact with the upper race seating surface 142 of the collar portion 122, and the lower race 166 is in contact with the thrust sliding portion 144.

  The operation of the hermetic compressor configured as described above will be described below.

  When an external power supply (not shown) is energized to the electric element 108, the rotor 106 rotates and the shaft 126 rotates accordingly. Then, the turning motion of the eccentric shaft portion 124 is converted into a reciprocating motion via the coupling mechanism 138 and transmitted to the piston 136. As a result, the piston 136 reciprocates in the compression chamber 130, and the compression element 110 performs a predetermined compression operation. Thereby, the refrigerant gas and the lubricating oil 112 are sucked into the compression chamber 130 from the cooling system (not shown), compressed, and then discharged again to the cooling system.

  As the shaft 126 rotates, the oil supply mechanism 150 of the shaft 126 pumps up the lubricating oil 112 and lubricates each sliding portion (not shown). A part of the lubricating oil 112 is supplied from the oil supply groove 152 to the thrust sliding portion 144 to lubricate the thrust ball bearing 146.

  At this time, the lubricant extracted from the polymer material is contained in the lubricating oil 112, but the total amount of the dimer to pentamer cyclic oligomer contained in the polymer material to be used is 500 mg or less. Therefore, naturally, the amount of oligomer contained in the lubricating oil 112 is 500 mg or less. Therefore, clogging of the capillary of the system due to the oligomer can be prevented, and the reliability of the system can be improved.

  Here, the relationship between the amount of oligomer and capillary blockage will be described with reference to FIG.

  Fig. 3 shows the capillary blockage rate when VG8 mineral oil containing about 200 mg to 600 mg of PET oligomer is used in advance as the lubricating oil for the compressor installed in the refrigerator system using the R600a refrigerant, and the refrigerator system is operated. FIG. The PET oligomer used was extracted from a PET film by a Soxhlet extraction method using chloroform.

  From the results shown in FIG. 3, when the PET oligomer amount is 300 mg or more, the clogging rate causing clogging of the capillary slightly increases to 2-3%, and when the PET oligomer amount is around 600 mg, the clogging rate is about 50%. It can be seen that the number has increased rapidly. This is because the amount of PET oligomer in the cooling system is increased by using the oil discharged into the cooling system as a medium, and the amount of the PET oligomer in the cooling system exceeds a certain value. It is shown that deposition is impossible without passing through the capillary portion, which is a decompression mechanism.

As a result, it is considered that the blocking rate is increasing. Therefore, PE into the cooling system
In order to limit the discharge amount (discharge amount) of the T oligomer, it is an effective means to limit the amount of oligomer extracted into oil as a medium to 600 mg or less. Furthermore, it is clear from the examination result in this Embodiment that the further effect is acquired by setting it as 300 mg or less.

  In recent years, in the system technology, there is a tendency to lower the viscosity of the lubricating oil in order to increase the efficiency. However, it goes without saying that, as the viscosity of the lubricating oil is lowered, naturally, components having a low molecular weight increase. This low molecular weight component enters between the molecules of the polymer material used in the compressor, and extracts a dimer to pentamer cyclic oligomer.

  Therefore, the increase in the low molecular weight component of the oil may increase the extraction speed of the oligomer, and may cause a large amount of extraction of the oligomer in a short period of time. However, the investigation shown in FIG. 3 conducted by encapsulating the oligomer in oil accelerated the tendency to increase the extraction speed of the oligomer to the maximum. Even if the extraction speed is increased, the capillary can be prevented from being blocked by setting the cyclic oligomer of dimer to pentamer to 500 mg or less.

  In the present embodiment, the refrigerant of R600a and the mineral oil having a viscosity of VG8 are described as the lubricating oil. However, if the viscosity of the oil used is VG3 to VG10, the same effect can be obtained from the viewpoint of the extraction speed. Is obtained. Further, the same effect can be obtained when the refrigerant to be used is a mixture mainly composed of R600a and the oil is any one of ester oil, alkylbenzene oil, polyvinyl ether, polyalkylene glycol, or a mixture of mineral oils.

  The refrigerant to be used is R134a, a mixture based on R134a, R1234yf, or a mixture based on R1234yf, and the oil is any one of ester oil, polyvinyl ether, polyalkylene glycol, or any of these. The same effect can be expected from the mixture as a result of oligomer extraction and capillary blockage.

  In this embodiment, the reciprocating refrigerant compressor has been described as an example. However, the same applies to other compressors having a sliding portion and a discharge valve, such as a rotary type, a scroll type, and a vibration type. Needless to say, an effect can be obtained.

  As described above, the refrigerant compressor according to the present invention can provide a highly reliable compressor using a low-viscosity lubricant, and thus can be widely applied to devices using a refrigeration cycle.

DESCRIPTION OF SYMBOLS 102 Sealed container 106 Rotor 108 Electric element 110 Compression element 112 Lubricating oil 126 Shaft 144 Thrust sliding part 146 Thrust ball bearing

Claims (3)

In an airtight container, lubricating oil made of ester oil having a viscosity of VG3 to VG10 , polyvinyl ether, polyalkylene glycol, or a mixture thereof is stored, and an electric element and driven by the electric element, R134a, a mixture mainly composed of R134a, or a compression element that compresses a refrigerant composed mainly of R1234yf or R1234yf is contained, and at least one member constituting the electric element and the compression element is a polymer material A refrigerant compressor in which the total amount of dimer to pentamer cyclic oligomers contained in the polymer is 500 mg or less. The refrigerant compressor according to claim 1, wherein the polymer material is polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyamide (PA), or polyphenylene sulfide (PPS). Said compression element, and configured to have a thrust bearing portion for supporting the weight of the shaft connected to the rotor and said rotor, wherein said thrust bearing portion, in claim 1 or 2 has a structure having a thrust ball bearing Refrigerant compressor.