JP4905464B2 - Refrigerant compressor - Google Patents

Description

  The present invention relates to a refrigerant compressor.

  In recent years, there has been an example in which the input is reduced by applying refrigeration oil having a low viscosity as means for improving the efficiency of a refrigerant compressor (see, for example, Patent Document 1).

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

  FIG. 2 is a longitudinal sectional view of a conventional refrigerant compressor described in Patent Document 1. In FIG. In FIG. 2, the airtight container 1 is filled with the refrigerant 2, and the refrigerating machine oil 3 is stored at the bottom, and the electric element 6 including the stator 4 and the rotor 5, and the reciprocating compression driven thereby. Contains element 7. As the refrigerant 2, R600a which is a hydrocarbon refrigerant is used.

  Next, details of the compression element 7 will be described below.

  The crankshaft 8 includes a main shaft 9 in which the rotor 5 is press-fitted and fixed, and an eccentric shaft 10 formed eccentrically with respect to the main shaft 9, and an oil supply pump 11 communicating with the refrigerating machine oil 3 is provided at the lower end.

  The cylinder block 12 includes a substantially cylindrical compression chamber 13, and a bearing portion 14 that supports the main shaft 9 is formed.

  The piston 15 fitted in the compression chamber 13 with a space is connected to the eccentric shaft 10 via a piston pin 16 by a connecting rod 17 which is a connecting means. The end surface of the compression chamber 13 is sealed with a valve plate 18.

  The head 19 forms a high pressure chamber (not shown), and is fixed to the valve plate 18 on the side opposite to the compression chamber 13. The muffler 20 is sandwiched between the valve plate 18 and the head 19.

  The suction tube 21 and the discharge tube 22 are fixed to the sealed container 1 and connected to a refrigeration cycle (not shown). The suction tube 21 guides the refrigerant 2 into the sealed container 1, and the discharge tube 22 sends the refrigerant 2 to the refrigeration cycle.

  The operation and action of the refrigerant compressor configured as described above will be described below.

  Electric power supplied from a commercial power source (not shown) is supplied to the electric element 6 to rotate the rotor 5 of the electric element 6 and rotate the crankshaft 8. The eccentric movement of the eccentric shaft 10 drives the piston 15 from the connecting rod 17 of the connecting means via the piston pin 16, and the piston 15 reciprocates in the compression chamber 13. The refrigerant 2 is introduced from the suction tube 21 into the sealed container 1 through a suction lead (not shown) from the refrigeration cycle. The refrigerant 2 is sucked from the muffler 20 and continuously compressed in the compression chamber 13. The compressed refrigerant 2 is discharged from a discharge valve (not shown) and sent out from the discharge tube 22 to the refrigeration cycle.

  At this time, the refrigerating machine oil 3 is pumped up by the oil supply pump 11 of the crankshaft 8 and lubricates each sliding portion such as the main shaft 9 and the piston 15.

In such a refrigerant compressor, oil having a viscosity of less than 8 mm ² / s at 40 ° C. is used for the refrigerating machine oil 3, and between the compression chamber 13 and the piston 15 which are sliding parts of the refrigerant compressor, A friction loss between the shaft 8 and the bearing portion 14 or the like has been reduced to achieve a highly efficient refrigerant compressor.

However, since the conventional refrigerant compressor uses the refrigerating machine oil 3 having a viscosity of less than 8 mm ² / s at 40 ° C., the refrigerating machine oil that can be held between the compression chamber 13 and the piston 15 because the viscosity is low. The amount of 3 was decreasing. Therefore, the refrigerant | coolant 2 leaked from the clearance gap between the compression chamber 13 and piston 15, and had the subject that leakage loss increased.

Further, if the gap between the compression chamber 13 and the piston 15 is made too small in order to reduce the leakage of the refrigerant 2 from the gap between the compression chamber 13 and the piston 15, the ambient temperature rises due to the compressed refrigerant 2. The outer wall of the piston 15 and the inner wall of the compression chamber 13 are in contact with each other, causing a problem of wear.
JP 62-059695 A

The present invention relates to a sealed container for storing refrigerating machine oil, an electric element, a compression element driven by the electric element, a cylinder block having a cylindrical compression chamber in the compression element, and a cylinder that reciprocates in the compression chamber. a refrigerant compressor comprising a shape of a piston, the difference between the diameter of the compression chamber diameter and piston 4μm or more and a range of 15 [mu] m, the refrigerating machine oil has a viscosity at a 40 ° C. is 8 mm ² / s in the first refrigerating machine oil is less, the viscosity at a 40 ° C. mixture of second refrigerating machine oil is 20 mm ² / s or more, is less than ^{8 mm} 2 / s viscosity when in 40 ° C. after mixing .

  With such a refrigerant compressor, the frictional resistance is reduced by reducing the viscosity resistance of the refrigeration oil, the amount of refrigeration oil retained between the compression chamber and the piston is increased, and the leakage loss that the refrigerant leaks is reduced. be able to. Furthermore, since the difference between the diameter of the compression chamber and the diameter of the piston can be optimized, wear due to contact between the compression chamber and the piston can be suppressed, and a highly efficient and highly reliable refrigerant compressor can be obtained.

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

(Embodiment)
FIG. 1 is a longitudinal sectional view of a refrigerant compressor according to an embodiment of the present invention.

  In FIG. 1, the refrigerant compressor 100 is filled with a refrigerant 102 in a sealed container 101, and refrigerating machine oil 103 is stored at the bottom of the sealed container 101. The refrigerant compressor 100 includes an electric element 106 including a stator 104 and a rotor 105 and a reciprocating compression element 107 driven by the electric element 106.

  Next, details of the compression element 107 will be described below.

  The crankshaft 108 made of iron-based metal includes a main shaft 109 in which the rotor 105 is press-fitted and fixed, and an eccentric shaft 110 formed eccentrically with respect to the main shaft 109. An oil supply pump 111 communicating with the refrigerator oil 103 is provided at the lower end of the crankshaft 108. The cylinder block 112 includes a substantially cylindrical compression chamber 113, and a bearing portion 114 that supports the main shaft 109 is formed.

  A piston 115 made of an iron-based metal fitted in the compression chamber 113 with a gap is connected to the eccentric shaft 110 through a piston pin 116 by a connecting rod 117 serving as a connecting means.

  The valve plate 118 is disposed so as to seal the end surface of the compression chamber 113. Further, the valve plate 118 is formed of a thin plate-shaped spring steel material, and forms a valve portion 120 including a suction lead 119 that opens and closes a suction hole (not shown).

  The head 121 is fixed on the opposite side of the compression chamber 113 with respect to the valve plate 118. The muffler 122 is sandwiched between the valve plate 118 and the head 121.

  The muffler 122 is formed from polybutylene terephthalate mixed with glass fibers.

  The suction tube 123 and the discharge tube 124 are fixed to the sealed container 101 and are connected to a refrigeration cycle (not shown). The suction tube 123 guides the refrigerant 102 into the sealed container 101, and the discharge tube 124 sends the refrigerant 102 to the refrigeration cycle.

  The operation and action of the refrigerant compressor configured as described above will be described below.

  Electric power supplied from a commercial power source (not shown) is supplied to the electric element 106 to rotate the rotor 105 of the electric element 106. The rotor 105 rotates the crankshaft 108, and the eccentric motion of the eccentric shaft 110 drives the piston 115 from the connecting rod 117 through the piston pin 116, and the piston 115 reciprocates in the compression chamber 113.

  The refrigerant 102 introduced into the sealed container 101 from the suction tube 123 is sucked into the compression chamber 113 through the muffler 122. The refrigerant 102 sucked into the compression chamber 113 is continuously compressed, and the compressed refrigerant 102 is sent out from the discharge tube 124 to the refrigeration cycle. The refrigerant 102 sent out to the refrigeration cycle is guided again into the sealed container 101 through the suction tube 123.

  At this time, the refrigerating machine oil 103 is pumped up by the oil supply pump 111 of the crankshaft 108, and the sliding parts such as the main shaft 109 and the piston 115 are lubricated.

  Next, the relationship between the difference between the diameter of the compression chamber 113 and the diameter of the piston 115, the type of refrigerating machine oil, and the efficiency of the compressor will be described using (Table 1).

  (Table 1) uses a refrigerant compressor of the same specification with an outer diameter of the piston 115 of 30 mm and changes the difference between the three types of refrigerating machine oil, the diameter of the compression chamber 113 and the diameter of the piston 115. It is the result of measuring efficiency.

The refrigerating machine oil A is the refrigerating machine oil 103 used in the refrigerant compressor according to the embodiment of the present invention. 3% by weight of mineral oil having a viscosity of 20 mm ² / s at 40 ° C. as the second refrigerator oil is mixed with mineral oil having a viscosity of 7.5 mm ² / s at 40 ° C. as the first refrigerator oil, and after mixing The viscosity of is 8 mm ² / s at 40 ° C.

The refrigerating machine oil B is for comparison with the refrigerating machine oil A, and is a mineral oil having a viscosity at 40 ° C. of 8 mm ² / s.

The refrigerating machine oil C is also used for comparison with the refrigerating machine oil A, and is a mineral oil having a viscosity of 10 mm ² / s at 40 ° C.

  The test conditions are condensation temperature = 54.4 ° C. and evaporation temperature = −23.3 ° C. Then, R600a was used as the refrigerant for the three refrigerant compressors, and the difference between the diameter of the compression chamber 113 and the diameter of the piston 115 was changed from 4 μm to 18 μm to compare the efficiency of the compressors.

(Table 1) shows that when the difference between the diameter of the compression chamber 113 and the diameter of the piston 115 is in the range of 4 μm or more and 18 μm or less, the refrigerating machine oil B composed only of mineral oil having a viscosity at 40 ° C. of 8 mm ² / s. Is used, the efficiency of the compressor is equal to or less than that when the refrigerating machine oil C composed only of mineral oil having a viscosity at 40 ° C. of 10 mm ² / s is used, and the efficiency of the compressor is not improved. It was.

  This is because when refrigeration oil B is used, the refrigeration oil B is more than the gap between the compression chamber 113 and the piston 115 because the viscosity of the refrigeration oil B is lower than the reduction in friction loss due to the reduction in the viscous resistance of the refrigeration oil B. Leaks. And it is guessed that the sealing performance of the gap between the compression chamber 113 and the piston 115 was lowered, the refrigerant 102 leaked, and as a result, the efficiency of the compressor was not improved.

  On the other hand, when the difference between the diameter of the compression chamber 113 and the diameter of the piston 115 is 4 μm or more and 15 μm or less, the refrigerating machine oil A which is the refrigerating machine oil 103 of the refrigerant compressor according to the embodiment of the present invention is used when the refrigerating machine oil C is used. More efficient compressor.

This can suppress the amount of the refrigerating machine oil A flowing out from the gap between the compression chamber 113 and the piston 115 by mixing mineral oil having a high viscosity of 20 mm ² / s at 40 ° C., In addition to the effect of reducing friction loss due to the use of low-viscosity oil, it is speculated that the reduction in the sealing performance between the compression chamber 113 and the piston 115 due to the refrigerating machine oil 103 can be suppressed, and the efficiency of the compressor has been improved. Is done.

Although detailed results are not shown, an oil having a viscosity lower than 7.5 mm ² / s at 40 ° C. is used as the first refrigerator oil, and a viscosity at 20 ° C. is 20 mm as the second refrigerator oil. As a result of measuring the efficiency of the compressor using various refrigerating machine oils of 8 mm ² / s or less when the viscosity after mixing was variously combined with various oils higher than ² / s and the viscosity after mixing was 40 ° C. And it has been confirmed that there is a similar effect on the refrigerating machine oil C.

  That is, if the difference between the diameter of the compression chamber 113 and the diameter of the piston 115 is in the range of 4 μm or more and 15 μm or less, the gap between the compression chamber 113 and the piston 115 is made too small to prevent wear and mixing. Friction loss can be reduced by the effect of the low viscosity of the refrigerating machine oil, and the deterioration of the sealing performance between the compression chamber 113 and the piston 115 can be suppressed by the effect of the second refrigerating machine oil. It can be set as a refrigerant compressor.

  In particular, during long-term operation, the compression chamber 113 and the piston 115 may slide and wear, and the gap between them may become large. In this case as well, the oil seal at the sliding portion between the compression chamber 113 and the piston 115 may be generated. Performance can be ensured, and high efficiency can be maintained.

In addition, in order to reduce friction loss of a sliding part etc., when using the refrigerating machine oil with a low viscosity of 8 mm ² / s or less as the first refrigerating machine oil at 40 ° C., the second refrigerating machine oil is 40 ° C. If a higher viscosity oil with a viscosity of 20 mm ² / s or more is selected and mixed, the effect can be obtained as in the case of the refrigerator oil A. Needless to say, the first refrigerating machine oil and the second refrigerating machine oil have numerous combinations of viscosities and mixing ratios.

In the refrigerant compressor according to the embodiment of the present invention, mineral oil is used as the first refrigerating machine oil having a viscosity of less than 8 mm ² / s at 40 ° C. However, ester oil or hard alkylbenzene oil may be used. good.

In the refrigerant compressor according to the embodiment of the present invention, mineral oil is used as the second refrigerating machine oil having a viscosity of 20 mm ² / s or more at 40 ° C., but ester oil, hard alkylbenzene oil, poly- α-olefin oil and polyalkylene glycol oil may be used.

Further, a refrigerant compressor in which the difference between the diameter of the compression chamber 113 and the diameter of the piston 115 was 15 μm was operated for 500 hours at a condensation temperature = 54.4 ° C. and an evaporation temperature = −23.3 ° C. As a result, when the refrigerating machine oil B having a viscosity at 40 ° C. of 8 mm ² / s was used, it was observed that oligomers thought to have been extracted from the muffler 122 were observed on the valve unit 120. However, mineral oil with a viscosity of 7.5 mm ² / s at 40 ° C. as the first refrigerating machine oil and 3% by weight or more of mineral oil with a viscosity of 20 mm ² / s at 40 ° C. as the second refrigerating machine oil When the refrigerating machine oil A constituted as described above was used, deposits such as oligomers and sludge were not observed.

This is because the mineral oil having a viscosity as high as 20 mm ² / s at 40 ° C. is mixed, so that the volatility of the refrigerating machine oil 103 can be suppressed, and oligomers and sludge remain and adhere to the valve portion 120 that becomes high temperature. This is presumed to have been possible to suppress this.

  Further, it is speculated that increasing the weight ratio of the second refrigerating machine oil from 3% by weight makes it more difficult to volatilize, so that the effect of suppressing the adhesion of the oligomer to the valve unit 120 is increased.

Although detailed results are not shown, an oil having a viscosity lower than 7.5 mm ² / s at 40 ° C. is used as the first refrigerator oil, and a viscosity at 20 ° C. is 20 mm as the second refrigerator oil. As a result of tests using various refrigerating machine oils having a viscosity of not more than 8 mm ² / s when the viscosity after mixing is various combinations of oils higher than ² / s, the second refrigerating machine oil has a weight of 3%. If more than% was mixed, deposits such as oligomers and sludge were not observed.

Therefore, the refrigerating machine oil A constituted by mixing 3% by weight or more of an oil having a viscosity of 20 mm ² / s or more at 40 ° C. with mineral oil having a viscosity of less than 8 mm ² / s at 40 ° C. is used. As a result, it is possible to suppress the oligomer adhesion to the valve portion or the like and to obtain a highly reliable compressor.

  Next, the compatibility between the refrigerant and the refrigerating machine oil will be described using (Table 2). The sealed container 101 is filled with R134a, which is an HFC refrigerant, R600a, which is an HC refrigerant, and refrigerating machine oil based on ester oil, mineral oil, and hard alkylbenzene oil, and is aged at 140 ° C. for 14 days. The compatibility with refrigeration oil was investigated.

  From (Table 2), the generation of sludge and the like was not observed in all combinations of refrigerant and refrigeration oil, and the results were satisfactory.

  Therefore, even when using HFC refrigerant, HC refrigerant, and refrigerating machine oil based on ester oil, mineral oil, and hard alkylbenzene oil, deterioration of refrigerating machine oil can be suppressed and a highly reliable refrigerant compressor can be obtained.

  In addition, the same effect is acquired even if it mixes and uses ester oil, mineral oil, and hard alkylbenzene oil.

  In addition, by adding an antioxidant to the refrigerating machine oil 103, deterioration of the refrigerating machine oil 103 can be suppressed even when exposed to a high temperature and high humidity environment during storage. can do.

  In addition, the refrigeration oil 103 is mixed with an extreme pressure additive such as tricresyl phosphate that can react with itself to form a film on the metal surface, thereby suppressing wear of the sliding portion. And a highly reliable refrigerant compressor.

  Further, an oily agent capable of being physically or chemically adsorbed with a metal such as a higher fatty acid, a higher alcohol, or a compound having an ester group may be added to the refrigerating machine oil 103. By adding such an oily agent, even if the oligomer is extracted from the muffler 122, it can be expected to suppress adhesion to the metal surface, and blockage of the flow path of the refrigerant 102 in the refrigeration cycle can be suppressed. Therefore, it can be set as a reliable refrigerant compressor.

The viscosity of the refrigerant compressor of embodiment, the difference between the diameters of the piston 115 in the compression chamber 113 4 [mu] m or more and a 15μm or less, refrigerating machine oil 103, when the 40 ° C. of above, the present invention There is less ^{8 mm} 2 / s, to 40 ° C. first refrigerating machine oil viscosity is less ^{8 mm} 2 / s at a, the viscosity at a 40 ° C. mixing the second refrigerating machine oil is 20 mm ² / s or more Thus, high compressor efficiency and high reliability can be realized.

  As described above, the refrigerant compressor of the present invention has high efficiency and can be widely applied to devices using a refrigeration cycle.

The longitudinal cross-sectional view of the refrigerant compressor in embodiment of this invention Vertical section of a conventional refrigerant compressor

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Refrigerant compressor 101 Airtight container 102 Refrigerant 103 Refrigerating machine oil 106 Electric element 107 Compression element 112 Cylinder block 113 Compression chamber 115 Piston

Claims (5)

A sealed container for storing refrigerating machine oil, an electric element, a compression element driven by the electric element, a cylinder block having a cylindrical compression chamber in the compression element, and a cylindrical shape that reciprocates in the compression chamber a piston and a refrigerant compressor provided with the compression chamber diameter and the difference between the diameter of the piston is 4μm or more and a or less in the range 15 [mu] m, the refrigerating machine oil, the viscosity at a 40 ° C. A ^second refrigerating machine oil having a viscosity at 40 ° C. of 20 mm ² / s or higher is mixed with the first refrigerating machine oil having a viscosity of 8 mm ² / s or lower and a viscosity at 40 ° C. of 8 mm ² / s or lower , Furthermore, the refrigerant compressor which made the weight ratio of said 2nd refrigerator oil 3weight% or more . The refrigerant compressor according to claim 1 , wherein the refrigerant to be compressed in the compression chamber is an HFC refrigerant or an HC refrigerant, and the refrigerating machine oil uses any one of ester oil, mineral oil, and hard alkylbenzene oil as a base oil . The refrigerant compressor according to claim 1 or 2 , wherein an antioxidant is added to the refrigerating machine oil . The refrigerant compressor according to claim 1 or 2 , wherein an extreme pressure additive is added to the refrigerating machine oil. The refrigerant compressor according to claim 1 or 2 , wherein an oily agent is added to the refrigerating machine oil.

Images