JP2023033383A - Hermetic refrigerant compressor and refrigerator-freezer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetic refrigerant compressor with a thrust bearing which eliminates a need of special treatment on sliding surfaces to achieve high efficiency and can avoid increase in an overall height without making a flange part excessively thin.

SOLUTION: In a hermetic refrigerant compressor, a thrust bearing (e.g., a thrust ball bearing 210) is provided on a thrust surface 136 of a main bearing 134. A crank shaft 120 has a flange part 128 which connects a spindle 124 with an eccentric shaft 122. A distance between an axis of the compression chamber 133 and a second end of a sliding surface (an end opposite to the compression chamber 133, a sliding surface lower end 139) of the main bearing 134 is a distance L, and a distance between the axis of the compression chamber 133 and a first end of the sliding surface (an end at the compression chamber 133 side, a sliding surface upper end 138) of the main bearing 134 is a distance La. When the distance L is in a range of 38 mm to 51 mm, the distance La is less than or equal to 16 mm.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a hermetic refrigerant compressor used in refrigerators, air conditioners, etc., and a freezer/refrigerator using the same.

2. Description of the Related Art In recent years, from the viewpoint of protecting the global environment, development of highly efficient hermetic refrigerant compressors that reduce the use of fossil fuels has been promoted. For example, in order to improve the efficiency, it has been proposed to form various coatings on the sliding surfaces of the sliding members provided in the hermetic refrigerant compressors and to use lubricating oil with a lower viscosity.

A hermetic refrigerant compressor stores lubricating oil in a hermetically sealed container, and houses an electric element and a compression element. The compression element includes, as sliding members, for example, a crankshaft, a piston, a connecting rod of a connecting means, etc., and includes the main shaft and main bearing of the crankshaft, the piston and bore, the piston pin and connecting rod, the eccentric shaft and connecting rod of the crankshaft. etc. form sliding portions with each other.

An example of a hermetic refrigerant compressor that uses low-viscosity lubricating oil is the reciprocating compressor disclosed in Patent Document 1. The lubricating oil used in this reciprocating compressor has a kinematic viscosity at 40° C. of 3 mm ² /S to 10 mm ² /S.

If the lubricating oil has a low viscosity, it becomes difficult to form an oil film. ) is subjected to a special treatment to facilitate the formation of an oil film. As a result, wear or seizure of the piston and connecting rod is prevented even when the lubricating oil of low viscosity is used and the oil film is thin.

In addition to using low-viscosity lubricating oil, a configuration in which a thrust bearing is provided in the main bearing is also known as an effort to improve efficiency. For example, in the hermetic compressor disclosed in Patent Document 2, a thrust bearing is provided on the thrust surface of the main bearing. , an upper race and a lower race provided above and below the rolling element. Since the rolling elements roll on the upper race and the lower race in a state of point contact, the thrust bearing functions as a rolling bearing. With such a rolling bearing, it is possible to rotate the main shaft with little friction while supporting a load in the vertical direction, so it is possible to effectively improve the efficiency of the hermetic refrigerant compressor.

By the way, the improvement of the efficiency of the hermetic refrigerant compressor can achieve the energy saving of the freezer/refrigerator using it. In addition to improving efficiency, it is known that low-speed operation of hermetic refrigerant compressors is one of the efforts to save energy in freezing and refrigerating equipment. A possible configuration has been proposed.

For example, in the compressor (hermetic refrigerant compressor) disclosed in Patent Document 3, the crankshaft A configuration is described in which the thickness of the radially protruding flange portion between the main shaft and the eccentric shaft is set to 4 mm or less. As a result, the entire cylinder can be lowered without reducing the cross-sectional area of the cylinder, so the lubricating oil can easily reach the upper surface of the piston, and the amount of lubricating oil supplied between the cylinder and the piston can be increased.

Japanese Patent No. 5222244 Japanese Patent No. 6469575 JP 2018-035727 A

In recent years, the efficiency of hermetic refrigerant compressors has reached an even higher level. By providing a thrust bearing to the main bearing as in Patent Document 2, the efficiency can be further improved, but the presence of the thrust bearing increases the overall height of the hermetic refrigerant compressor. When such a hermetic refrigerant compressor is installed in a freezing/refrigerating apparatus, the mechanical chamber of the freezing/refrigerating apparatus needs to be expanded, and the internal volume of the freezing/refrigerating apparatus is reduced.

In Patent Document 2, as a prior art for avoiding an increase in overall height, an example of reducing the thickness of the supporting portion of the cylinder block is given. It points out the problem that the deformation of the main bearing becomes easy due to the decrease in Therefore, Patent Document 2 adopts a configuration that can avoid an increase in overall height without reducing the thickness of the support portion.

On the other hand, in Patent Document 3, as described above, the thickness of the flange portion located between the main shaft and the eccentric shaft of the crankshaft is reduced to 4 mm or less in order to avoid an increase in overall height. However, if the thickness of the flange portion is made too thin, the eccentric shaft will be inclined with respect to the main shaft. Both Patent Literature 2 and Patent Literature 3 describe that if the crankshaft as a whole tilts within the main bearing, it hinders efficiency improvement. However, neither document assumes the inclination of the eccentric shaft with respect to the main shaft.

Furthermore, as in Patent Document 1, the use of a low-viscosity lubricating oil can reduce the coefficient of friction between the sliding members that constitute the sliding portion, thereby achieving high efficiency. May reduce wear resistance. In Patent Literature 1, as described above, the sliding surface is specially treated to avoid deterioration in wear resistance, but the special treatment causes an increase in manufacturing cost.

The present invention has been made to solve such problems, and in order to achieve high efficiency, it does not require special treatment on the sliding surface and does not make the flange excessively thin. It is an object of the present invention to provide a hermetic refrigerant compressor with a thrust bearing that can avoid an increase in overall height.

In order to solve the above-described problems, a hermetic refrigerant compressor according to the present invention compresses a hermetic container that stores lubricating oil, an electric element housed in the hermetic container, and a refrigerant that is driven by the electric element. a compression element comprising a crankshaft having a main shaft and an eccentric shaft; a cylinder block provided with a compression chamber; a piston reciprocally inserted into the compression chamber; A main bearing that supports the main shaft; and a thrust bearing that is provided on a thrust surface of the main bearing. The first end is the first end, the opposite end is the second end, the distance between the axial center of the compression chamber and the second end of the sliding surface of the main bearing is L, the axial center of the compression chamber and the main bearing are When the distance from the first end of the sliding surface of the bearing is La, the distance La is 16 mm or less when the distance L is in the range of 38 mm to 51 mm.

According to the above configuration, in a hermetic refrigerant compressor provided with a thrust bearing, when the distance L affecting the overall height is specified within a predetermined range, the axial center of the compression chamber and the first end of the sliding surface of the main bearing The upper limit of the distance La is specified as 16 mm. As a result, it is possible to avoid an increase in overall height without excessively thinning the flange portion, which contributes to the stability of the eccentric shaft, and reduce the load on the spindle without applying special treatment to the sliding surface. can do. As a result, the efficiency can be further improved without increasing the overall height of the hermetic refrigerant compressor. Moreover, since the flange portion is not excessively thinned, it is possible to achieve high efficiency and good reliability.

Further, a freezing/refrigerating apparatus according to the present invention includes the hermetic refrigerant compressor having the above configuration, a radiator, a pressure reducing device, and a heat absorber. be.

According to the above configuration, in a hermetic refrigerant compressor having a thrust bearing, it is possible to avoid an increase in overall height without thinning the flange portion, and the sliding surface does not require special treatment. can also reduce the load on the spindle. Therefore, the hermetic refrigerant compressor has high efficiency and good reliability. By including such a highly efficient and highly reliable hermetic refrigerant compressor in a freezer/refrigerator, power consumption can be reduced and reliability can be improved.

The above objects, other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.

In the present invention, with the above configuration, in order to achieve high efficiency, it is possible to avoid an increase in the total height without requiring special treatment on the sliding surface and without excessively thinning the flange portion. , it is possible to provide a hermetic refrigerant compressor with a thrust bearing.

FIG. 1 is a schematic cross-sectional view showing an example configuration of a hermetic refrigerant compressor according to an embodiment of the present disclosure. FIG. 2 is a partial cross-sectional view of the hermetic refrigerant compressor shown in FIG. 1, schematically showing an example of the distance L, the distance La, and the load applied to the main shaft sliding portion (main shaft load). is. FIG. 3 is a partial cross-sectional view of the hermetic compressor shown in FIG. 1, schematically showing an example of a configuration of a main part of a thrust bearing in the hermetic refrigerant compressor. FIG. 4 is a schematic diagram showing an example of the configuration of a freezing/refrigerating apparatus including the hermetic refrigerant compressor shown in FIG. FIG. 5 is a graph showing an example of the relationship between the distance La, the main shaft load F, and the inclination angle of the eccentric shaft in the hermetic refrigerant compressor shown in FIG. FIG. 6A is a graph showing an example of the molecular weight distribution of the lubricating oil used in the hermetic refrigerant compressor shown in FIG. 1 is a graph showing an example of the coefficient of performance relationship of the hermetic refrigerant compressor shown in FIG. FIG. 7 is a graph showing an example of the relationship between the rotational speed and compressor efficiency in the hermetic refrigerant compressor shown in FIG.

A hermetic refrigerant compressor according to the present disclosure includes a hermetic container that stores lubricating oil, an electric element that is housed in the hermetic container, and a compression element that is driven by the electric element and compresses a refrigerant. Elements include a crankshaft having a main shaft and an eccentric shaft, a cylinder block provided with a compression chamber, a piston reciprocally inserted into the compression chamber, connecting means connecting the piston and the eccentric shaft, and the A main bearing that supports a main shaft; and a thrust bearing provided on a thrust surface of the main bearing. The end is the second end, the distance between the axial center of the compression chamber and the sliding surface second end of the main bearing is L, and the axial center of the compression chamber and the sliding surface first end of the main bearing are separated. is 16 mm or less when the distance L is in the range of 38 mm to 51 mm.

According to the above configuration, in a hermetic refrigerant compressor provided with a thrust bearing, when the distance L affecting the overall height is specified within a predetermined range, the axial center of the compression chamber and the first end of the sliding surface of the main bearing The upper limit of the distance La is specified as 16 mm. As a result, it is possible to avoid an increase in overall height without excessively thinning the flange portion, which contributes to the stability of the eccentric shaft, and reduce the load on the spindle without applying special treatment to the sliding surface. can do. As a result, the efficiency can be further improved without increasing the overall height of the hermetic refrigerant compressor. Moreover, since the flange portion is not excessively thinned, it is possible to achieve high efficiency and good reliability.

In the hermetic refrigerant compressor configured as described above, the thrust bearing is in rolling contact with a lower race located on the thrust surface and an upper race located opposite the lower race. A plurality of rolling elements may be provided, and the rolling elements may be balls.

According to the above configuration, even if the thrust bearing is a general ball bearing, it is possible to avoid an increase in overall height and reduce the load on the main shaft without applying special treatment to the sliding surface. High efficiency can be achieved.

Further, in the hermetic refrigerant compressor having the above configuration, the lubricating oil may have a kinematic viscosity at 40° C. of 1 mm ² /S to 7 mm ² /S.

According to the above configuration, lubricating oil having a lower viscosity is used. By specifying the distance La to be 16 mm or less when the distance L is specified within a predetermined range, the load on the spindle can be reduced without thinning the flange portion and without applying special treatment to the sliding surface. can be reduced. Therefore, even if a low-viscosity lubricating oil is used, it is possible to effectively suppress or avoid deterioration in the wear resistance of the sliding portion (spindle sliding portion) composed of the main shaft and main bearings. As a result, it is possible to further improve the efficiency without requiring a special treatment for the sliding surface and without increasing the overall height.

Further, in the hermetic refrigerant compressor having the above configuration, the lubricating oil has an average mass molecular weight of 150 to 400 and contains 0.5% by mass or more of a high molecular weight component, and the high molecular weight component may have a mass molecular weight of 500 or more.

According to the above configuration, the low-viscosity lubricating oil has an average molecular weight within a predetermined range, and the lubricating oil contains a high-molecular-weight component having a relatively large molecular weight. This makes it possible to form a suitable oil film even with a low-viscosity lubricating oil. Therefore, it is possible to effectively suppress or avoid deterioration of the wear resistance of the main shaft sliding portion. As a result, it is possible to further improve the efficiency without requiring a special treatment for the sliding surface and without increasing the overall height.

Further, in the hermetic refrigerant compressor having the above configuration, the lubricating oil may contain an oily agent.

According to the above configuration, the low-viscosity lubricating oil containing the high-molecular-weight component further contains the oily agent. Therefore, the oily agent can further facilitate the formation of an oil film of lubricating oil. As a result, it is possible to more preferably achieve low friction in the main shaft sliding portion.

Further, in the hermetic refrigerant compressor having the above configuration, the oily agent may be an ester compound.

According to the above configuration, since the oily agent contained in the lubricating oil is an ester compound, the oily agent has an ester bond. Therefore, the polarity derived from this ester bond can improve the ability of the oily agent to form an oil film. As a result, it is possible to more preferably achieve low friction in the main shaft sliding portion.

Further, in the hermetic refrigerant compressor having the above configuration, the lubricating oil may have a distillation fraction of 0.1% or more at a distillation temperature of 300°C and an end point of 440°C or more.

According to the above configuration, the low-viscosity lubricating oil containing the high-molecular-weight component contains a component having a high distillation temperature. Therefore, even if the temperature of the sliding portion rises by reducing the sliding area, evaporation of the lubricating oil can be effectively avoided or suppressed. can be done. As a result, it is possible to more preferably achieve low friction in the main shaft sliding portion.

Further, in the hermetic refrigerant compressor having the above configuration, the lubricating oil may contain a slidability modifier of 100 ppm or more in terms of sulfur element weight.

According to the above configuration, a suitable amount of a sulfur-based slidability modifier is added to a low-viscosity lubricating oil containing a high-molecular-weight component. Since this slidability modifier can improve the wear resistance of the sliding surface, it is possible to promote the reduction of the friction of the sliding portion of the main shaft. Therefore, even in a state where the sliding area is reduced, it is possible to more preferably achieve low friction in the main shaft sliding portion.

Further, in the hermetic refrigerant compressor having the above configuration, the lubricating oil may contain a phosphorus-based extreme pressure additive.

According to the above configuration, the phosphorus-based extreme pressure additive is added to the low-viscosity lubricating oil containing the high-molecular-weight component. Since the extreme pressure additive can improve the wear resistance of the sliding surface, it is possible to promote the low friction of the sliding portion of the main shaft. Therefore, even in a state where the sliding area is reduced, it is possible to more preferably achieve low friction in the main shaft sliding portion.

Further, in the hermetic refrigerant compressor having the above configuration, the lubricating oil may be at least one selected from the group consisting of mineral oil, alkylbenzene oil, and ester oil.

According to the above configuration, the lubricating oil itself is not particularly limited, but at least one of mineral oil, alkylbenzene oil, and ester oil is used as the lubricating oil. As a result, when the viscosity of the lubricating oil is lowered to contain a high-molecular-weight component, the coefficient of friction of the main shaft sliding portion can be easily reduced even when the sliding area is reduced.

Further, in the hermetic refrigerant compressor having the above configuration, the electric element may be inverter driven at a plurality of operating frequencies.

According to the above configuration, even during low-speed operation or high-speed operation in inverter drive, a suitable oil film is formed on the main shaft sliding portion by the low-viscosity lubricating oil containing the high-molecular-weight component. Even when the sliding area is reduced, the coefficient of friction of the shaft can be favorably reduced. As a result, the sliding portion of the main shaft can have a low coefficient of friction and good wear resistance regardless of the operating speed, so the efficiency and reliability of the hermetic refrigerant compressor can be improved. can.

Further, the hermetic refrigerant compressor configured as described above may be configured to be operated at a rotational speed of 35 rps or less.

According to the above configuration, even during low-speed operation, the sliding portion of the main shaft can have a low coefficient of friction and good wear resistance. can be good.

A freezing/refrigerating apparatus according to the present disclosure includes the hermetic refrigerant compressor, the radiator, the pressure reducing device, and the heat absorber configured as described above, and has a refrigerant circuit in which these are connected in a ring by pipes.

According to the above configuration, in a hermetic refrigerant compressor having a thrust bearing, it is possible to avoid an increase in overall height without thinning the flange portion, and the sliding surface does not require special treatment. can also reduce the load on the spindle. Therefore, the hermetic refrigerant compressor has high efficiency and good reliability. By including such a highly efficient and highly reliable hermetic refrigerant compressor in a freezer/refrigerator, power consumption can be reduced and reliability can be improved.

Hereinafter, typical embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals throughout all the drawings, and duplicate descriptions thereof will be omitted.

(Embodiment 1)
[Configuration of Compressor]
First, a typical configuration example of a hermetic refrigerant compressor according to Embodiment 1 of the present disclosure will be specifically described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a hermetic refrigerant compressor 100 (hereinafter, basically abbreviated as refrigerant compressor 100) according to Embodiment 1 of the present disclosure.

As shown in FIG. 1, the refrigerant compressor 100 fills the closed container 102 with, for example, R600a as the refrigerant gas 181, and reserves mineral oil as the lubricating oil 180 at the bottom. A compressor main body 108 is accommodated in the sealed container 102 , and this compressor main body 108 is elastically supported by a suspension spring 190 . Compressor body 108 also includes electric element 104 and compression element 106 .

Electric element 104 is composed of at least a stator 150 and a rotor 152 . The compression element 106 is a reciprocating arrangement driven by the electric element 104 and includes a crankshaft 120, a cylinder block 130, a piston 140, coupling means 142, and the like. The crankshaft 120 comprises at least a main shaft 124 to which the rotor 152 is shrink-fitted, an eccentric shaft 122 formed eccentrically with respect to the main shaft 124, and a flange portion 128 connecting the main shaft 124 and the eccentric shaft 122. .

As shown in FIG. 1 , the eccentric shaft 122 of the crankshaft 120 is positioned above the refrigerant compressor 100 and the main shaft 124 is positioned below the refrigerant compressor 100 . Therefore, even when describing the position of the crankshaft 120, this vertical positional relationship (direction) is used. For example, the upper end of the eccentric shaft 122 faces the inner upper surface of the closed container 102 , and the lower end of the eccentric shaft 122 connects to the main shaft 124 .

The upper end of the main shaft 124 is connected to the eccentric shaft 122 , the lower end of the main shaft 124 faces the lower inner surface of the sealed container 102 , and the lower end of the main shaft 124 is immersed in lubricating oil 180 . An oil supply mechanism 125 is provided below the crankshaft 120, that is, below the main shaft 124. The oil supply mechanism 125 supplies the lubricating oil 180 from the lower end of the main shaft 124 immersed in the lubricating oil 180 to the upper end of the eccentric shaft 122. supply.

Lubricating oil 180 used in the present disclosure ^is not particularly limited ^. Those having a molecular weight of 150 to 400 and containing 0.5% by mass or more of high molecular weight components are used. This high molecular weight component has a mass molecular weight of 500 or more. In addition, in Embodiment 1, low-viscosity mineral oil is used as a more specific lubricating oil 180, but the lubricating oil 180 is not limited to this. For example, as described later, an oily substance other than mineral oil may be used, and an oily agent or extreme pressure additive may be contained.

A cylinder 132 forming a compression chamber 133 and a main bearing 134 rotatably supporting the main shaft 124 are integrally formed in the cylinder block 130 . The main bearing 134 is formed in a tubular shape extending vertically with respect to the cylinder block 130, and its inner peripheral surface is a sliding surface. Main bearing 134 also includes thrust surface 136 and tubular extension 137 .

The thrust surface 136 is a planar portion that extends in a direction (vertical direction, horizontal direction) perpendicular to the axial center, that is, the extension direction (vertical direction) of the main shaft 124 . The tubular extension part 137 has a tubular shape (cylindrical shape) that extends further upward than the thrust surface 136 , in other words, it is a part that extends upward from the main body of the tubular main bearing 134 . Therefore, the tubular extension 137 has an inner peripheral surface (sliding surface) facing the outer peripheral surface (sliding surface) of the main shaft 124 together with the main bearing 134 body. A thrust ball bearing 210 is provided on the thrust surface 136 of the main bearing 134 . A specific configuration of thrust ball bearing 210 will be described later.

The compression chamber 133 is a cylindrical (columnar) bore formed in the cylinder block 130, and the piston 140 is inserted into the compression chamber 133 so as to be able to reciprocate. Therefore, the compression chamber 133 is closed by inserting the piston 140 . The connecting means 142 is made of cast aluminum, for example, supports the eccentric shaft 122 and is connected to the piston 140 . Therefore, the eccentric shaft 122 and the piston 140 are connected by the connecting means 142 .

In the present disclosure, as shown in FIG. 1 , compression chamber 133 is positioned above main bearing 134 in cylinder block 130 . Therefore, the axial center of the compression chamber 133 (the central axis of the cylindrical or columnar space (bore)) is located above the main bearing 134 . In the present disclosure, the vertical distance between the axial center of the compression chamber 133 and the lower end of the sliding surface of the main bearing 134 is L, and the vertical direction between the axial center of the compression chamber 133 and the upper end of the sliding surface of the main bearing 134 is is 16 mm or less when the distance L is in the range of 38 mm to 51 mm. Both the distance L and the distance La can be said to be the distance (interval) from the axial center of the compression chamber 133 to the end of the sliding surface.

The outer peripheral surface of main shaft 124 of crankshaft 120 includes a sliding surface 126 and a non-sliding surface 127 . In the present disclosure, the “sliding surface” is the outer peripheral surface or inner peripheral surface of a plurality of sliding members that constitute the sliding portion, and is a surface that is slidably in contact with the other inner peripheral surface or outer peripheral surface. means that A "non-sliding surface" is a surface that, unlike a sliding surface, does not come into contact with the other inner peripheral surface or outer peripheral surface. In this embodiment, the non-sliding surface 127 is formed by making the outer diameter of the main shaft 124 smaller than that of the sliding surface 126 (by narrowing the outer diameter, recessing from the sliding surface 126, or forming a hollow portion). Configuration.

In the present embodiment, the cylinder block 130 is made of cast iron, for example, forms a substantially cylindrical compression chamber 133 , and includes a main bearing 134 that supports a main shaft 124 of the crankshaft 120 . The inner peripheral surface of the main bearing 134 is slidably in contact with the outer peripheral surface, that is, the sliding surface of the main shaft 124 . Therefore, the inner peripheral surface of the main bearing 134 also serves as a sliding surface.

When the main shaft 124 is supported by the main bearing 134 , the non-sliding surface 127 of the main shaft 124 is located between the upper end and the lower end of the main bearing 134 . Therefore, the non-sliding surface 127 is not exposed from the upper end and the lower end of the main bearing 134 , and both the upper end and the lower end of the main bearing 134 are in contact with the sliding surface 126 . The sliding surface 126 of the main shaft 124 may constitute a part of the outer peripheral surface in this manner, or may constitute the entire outer peripheral surface of the main shaft 124 .

The electric element 104 is composed of a rotor 152 and a stator 150 arranged coaxially with the rotor 152 so as to surround the rotor 152 . The stator 150 is arranged on the outer diameter side of the rotor 152 and fixed to the leg portion of the cylinder block 130 so as to maintain a substantially constant gap with the rotor 152 . Also, the rotor 152 is fixed to the main shaft 124 .

In the first embodiment, in closed container 102, electric element 104 is positioned on the lower side and compression element 106 is positioned on the upper side. However, the configuration of the refrigerant compressor 100 according to the present disclosure is not limited to this, and the electric element 104 may be positioned on the upper side and the compression element 106 may be positioned on the lower side. Further, in Embodiment 1, the electric element 104 is of an inner rotor type, and the rotor 152 is coaxial with the stator 150 and rotatably arranged on the inner periphery of the stator 150 . However, the configuration of the electric element 104 is not limited to this, and may be an outer rotor type, that is, a configuration in which the rotor 152 is coaxial with the stator 150 and rotatably arranged on the outer periphery of the stator 150. .

In the refrigerant compressor 100 having such a configuration, electric power supplied from a commercial power source (not shown) is first supplied to the electric element 104, so that the rotor 152 of the electric element 104 is rotated. The rotor 152 rotates the crankshaft 120, and the eccentric motion of the eccentric shaft 122 is transmitted to the piston 140 through the connecting means 142, thereby driving the piston 140 to reciprocate. Refrigerant gas 181 guided into closed container 102 by the reciprocating motion of piston 140 is sucked into compression chamber 133 and compressed.

A specific driving method of the refrigerant compressor 100 is not particularly limited. For example, the refrigerant compressor 100 may be driven by simple on/off control, or may be driven by an inverter at multiple operating frequencies. That is, the refrigerant compressor 100 according to Embodiment 1 may include an inverter circuit so that the electric element 104 can be rotationally driven at a plurality of operating rotation speeds.

The operating rotation speed of the electric element 104 is not particularly limited, but is generally in the range of 17 to 75 rps (revolutions per second or rotations per second). The upper limit of the operating speed may be 80 rps, and the lower limit of the operating speed may be 13 rps. In the present disclosure, it is possible to improve the efficiency of the refrigerant compressor 100 both during high-speed operation and during low-speed operation, and particularly during low-speed operation. The number of revolutions during low-speed operation is not particularly limited, but in the present disclosure, for example, 35 rps or less can be mentioned as described later.

Among the plurality of sliding portions provided in the refrigerant compressor 100, the main shaft 124 of the crankshaft 120 is rotatably fitted to the main bearing 134 as described above to form a sliding portion. Therefore, for convenience of explanation, the sliding portion constituted by the main shaft 124 and the main bearing 134 is called "main shaft sliding portion". As the crankshaft 120 rotates, the lubricating oil 180 is supplied to each sliding portion from the oil supply pump. Each sliding part is thereby lubricated. Lubricating oil 180 also provides a seal between piston 140 and compression chamber 133 . In the present disclosure, as will be described later, lubricating oil 180 having a low viscosity and containing a high molecular weight component can be suitably used. Such lubricating oil 180 can satisfactorily lubricate sliding parts. At the same time, good sealing can also be achieved between the piston 140 and the compression chamber 133 .

[Thrust bearing and distance L, La]
Next, a specific configuration example of the thrust bearing provided in the refrigerant compressor 100 according to Embodiment 1, and the distance L that is the distance from the axial center of the compression chamber 133 to the end of the sliding surface and an example of the distance La will be described with reference to FIGS. 2 and 3 in addition to FIG. 2 and 3 schematically show a part of the cross-sectional view of the refrigerant compressor 100 shown in FIG. 1, and FIG. An example of the load applied (main shaft load) is schematically shown, and FIG. 3 schematically shows an example of the main part configuration of the thrust bearing.

As shown in FIG. 1, the main bearing 134 has a tubular or cylindrical shape that extends vertically with respect to the cylinder block 130 that extends horizontally within the closed container 102 . there is The main bearing 134 body extends below the cylinder block 130 . As described above, since the tubular extension 137 extends above the cylinder block 130, the main bearing 134 main body and the tubular extension 137 form a single tubular or cylindrical structure. have.

The inner peripheral surface of the main bearing 134 is a sliding surface as described above. Therefore, as shown in FIG. 2 , the upper edge of the inner peripheral surface of the main bearing 134 is the sliding surface upper end 138 and the lower edge of the main bearing 134 is the sliding surface lower end 139 . In Embodiment 1, since the main bearing 134 has the tubular extension 137 on the upper side, the sliding surface upper end 138 corresponds to the upper edge of the inner peripheral surface of the tubular extension 137 . In other words, the tubular extension 137 can be said to be an "extension" of the main bearing 134 extending upward. By providing such a tubular extension 137, when the upper limit of the distance La is specified, the overall length of the main bearing 134 can be increased without increasing the overall height of the refrigerant compressor 100. It is possible to improve the attitude of the crankshaft 120 during operation.

As shown in FIG. 3, the inner surface of the upper end of the tubular extension 137 may be chamfered. In this case, the inner edge of the chamfered portion of the inner surface of the tubular extension portion 137 becomes the sliding surface upper end 138 of the main bearing 134 . If the inner surface of the upper end of the tubular extension 137 is not chamfered or otherwise processed, the upper edge of the inner surface of the tubular extension 137 becomes the sliding surface upper end 138 of the main bearing 134 .

Then, as shown in FIG. 2, the distance between the axial center of the compression chamber 133 and the lower end 139 of the sliding surface of the main bearing 134 is defined as "distance L" as described above, and the distance between the axial center of the compression chamber 133 and the main bearing 134 is When the distance from the sliding surface upper end 138 is “distance La”, in the refrigerant compressor 100 according to the present disclosure, even if a thrust bearing such as the thrust ball bearing 210 is provided, the distance L is 38 mm to 51 mm. When within the range, the distance La is 16 mm or less.

Refrigerant compressor 100 according to the present disclosure is provided with a thrust bearing on thrust surface 136 of main bearing 134 . The specific configuration of the thrust bearing is not particularly limited, and various types of rolling bearings may be used. In Embodiment 1, a thrust ball bearing 210 is used as shown in FIGS. 1 to 3. FIG. As shown in FIG. 3, the thrust ball bearing 210 rollably abuts a lower race 206 located on the thrust surface 136 and an upper race 202 located opposite the lower race 206 therebetween. It has balls 204 as a plurality of rolling elements.

A thrust ball bearing 210 is arranged on the outer peripheral side of the tubular extension 137 and a plurality of balls 204 are housed in a retainer 205 . The upper race 202 and the lower race 206 are, for example, annular metal flat plates and are arranged parallel to each other. Note that arc-shaped grooves may be provided in the upper race 202 and the lower race 206 .

In the configuration example shown in FIG. 3, a lower race 206, a ball 204, and an upper race 202 are stacked in this order on the thrust surface 136 while being in contact with each other. I am seated. This constitutes the thrust ball bearing 210 .

Thrust ball bearing 210 is a rolling bearing in which balls 204 roll on upper race 202 and lower race 206 in point contact. Therefore, it is possible to rotate the main shaft 124 with little friction while supporting a vertical load by the thrust ball bearing 210 . Although the thrust ball bearing 210 is a "ball bearing" having balls 204 as rolling elements, it may be a "roller bearing" having rollers as rolling elements, or other rolling bearings.

As a result, the bearing function of the slide bearing is changed to the thrust ball bearing 210, which is a rolling bearing, thereby reducing the loss, so that the efficiency of the refrigerant compressor 100 can be effectively improved. However, providing a thrust bearing such as the thrust ball bearing 210 generally increases the overall height of the refrigerant compressor 100 . On the other hand, in the refrigerant compressor 100 according to the present disclosure, regarding the distance L and the distance La relative to the axial center of the compression chamber 133, when the distance L is within the range of 38 mm to 51 mm, the distance La is 16 mm or less. is set to be The effect (function) of setting the upper limit of the distance La will be described more specifically.

When refrigerant compressor 100 employs a cantilever bearing structure as in Embodiment 1, sliding loss W at main shaft 124 during operation of refrigerant compressor 100 can be simply expressed as follows: can be obtained by the following formula (1). Note that F in the following equation (1) is the load on the main shaft 124 , μ is the coefficient of friction between the main shaft 124 and the main bearing 134 , and v is the sliding speed of the main shaft 124 .
W=F×μ×v (1)
Further, the load F applied to the main shaft 124 (main shaft load F) can be obtained by the following formula (2). As shown in FIG. 2, Fa in the following equation (2) is the load from the piston 140 (piston load Fa), and La is the distance between the axial center of the compression chamber 133 and the sliding surface upper end 138 as described above. and L is also the distance between the axial center of the compression chamber 133 and the lower end 139 of the sliding surface as described above.
F=Fa×{1+La/(L−La)} (2)
Based on these formulas (1) and (2), as an effort to improve the efficiency of the refrigerant compressor 100, that is, to reduce the sliding loss W in the main shaft 124, the friction coefficient μ is reduced. Alternatively, the main shaft load F may be reduced, or both may be used. Furthermore, methods for reducing the spindle load F include reducing the distance La, increasing the distance L, or adopting both.

However, if the distance L is to be increased, the overall height of the refrigerant compressor 100 must be increased (higher). When the overall height is increased in this way, it becomes necessary to expand the engine room (mechanical room) of the freezer/refrigerator in which the refrigerant compressor 100 is mounted, which leads to a reduction in the internal volume of the freezer/refrigerator. Therefore, in order to reduce the spindle load F, it is assumed that the distance La is reduced without changing the distance L.

However, if the distance La is simply reduced, the thickness of the supporting portion of the cylinder block 130 is reduced as described in Patent Document 2 as a prior art, or the flange as described in Patent Document 3. A method of reducing the thickness of the portion 128 to 4 mm or less, that is, a method of thinning (part of) a specific member (thinning method) can be considered.

However, if such a thinning method is adopted, it will result in deformation of other members. Specifically, if the thickness of the support portion is reduced, the rigidity of the cylinder block 130 is reduced and the main bearing 134 is likely to be deformed. In particular, an increase in inclination of the eccentric shaft 122 due to the thinning of the flange portion 128 has not been assumed at all in the prior art. As described above, when the distance La is reduced by the thinning method, the efficiency of the refrigerant compressor 100 can be improved, but the reliability of the refrigerant compressor 100 may be lowered due to deformation of specific members.

In Patent Document 2, in order to avoid the thinning method, the total height of the sealed container 102 is set to within 6 times the diameter of the piston 140, and half or more of the total length of the main bearing 134 is accommodated in the hole of the rotor 152. Alternatively, when the electric element 104 is of the outer rotor type, a configuration is adopted in which the lower end of the main bearing 134 extends below the stator 150 .

On the other hand, as a result of intensive studies by the present inventors, as shown in the results of Example 1 described later, by setting the upper limit of the distance La to a predetermined value, ie, 16 mm or less, the thinning method is not adopted. However, we have independently found that it is possible to achieve both high efficiency and good reliability (see FIG. 5).

That is, according to the above formulas (1) and (2), in an effort to reduce the sliding loss W in the main shaft 124, it is possible to reduce the distance La in order to reduce the main shaft load F. Conventionally, no particular consideration has been given to lowering the reliability of the refrigerant compressor 100 by making it smaller.

However, the present inventors have found that when the distance La is reduced, the slight inclination (inclination angle) of the eccentric shaft 122 that occurs during operation of the refrigerant compressor 100 contributes not only to the reliability of the refrigerant compressor 100 but also to high efficiency. also found to be involved. In other words, the inventors of the present invention found that the change in the distance La and the inclination of the eccentric shaft 122 are important factors in reducing the main shaft load F to achieve high efficiency and good reliability of the refrigerant compressor 100. independently discovered that it is important to set the upper limit of the distance La to 16 mm or less.

In the present disclosure, when the distance L is set in the range of 38 mm to 51 mm, the distance La is set to 16 mm or less, and the preferred range is 12 mm to 16 mm (that is, 12 mm as an example of the lower limit). . Therefore, it is not necessary to increase (increase) the overall height of the refrigerant compressor 100 . As a result, it is possible not only to achieve high efficiency while maintaining good quality (especially reliability) of the refrigerant compressor 100, but also to eliminate the need to expand the engine room (mechanical room) of the freezer/refrigerator. , the internal volume of the freezer/refrigerator can be sufficiently secured.

In addition, in Patent Document 2, the total height of the sealed container 102 is defined based on the diameter of the piston 140, but in the present disclosure, the diameter of the piston 140 or the inner diameter of the compression chamber 133 into which the piston 140 is inserted need not be particularly limited. In the refrigerant compressor 100 according to the present disclosure, the inner diameter (bore diameter) of the compression chamber 133 (bore) is not particularly limited, but may be within the range of 22 mm to 28 mm in the present embodiment. If the distance La is set to 16 mm or less when the distance L is within the range of 38 mm to 51 mm, not only is it not necessary to make the flange portion 128 excessively thin, but also the inner diameter of the compression chamber 133 is kept within the above range. can do.

Further, based on the above formulas (1) and (2), in addition to reducing the distance La, as an approach to reduce the sliding loss W, it is possible to reduce the coefficient of friction μ between the main shaft 124 and the main bearing 134. is assumed. However, when simply trying to reduce the coefficient of friction μ, it is conceivable to use a low-viscosity lubricating oil 180 as described in Patent Document 1, but if the lubricating oil 180 has a low viscosity, a sufficient oil film for lubrication becomes difficult to form. If a sufficient oil film is not formed, there is a possibility that the main shaft 124 and the main bearing 134 will be worn or seized.

On the other hand, as a result of intensive studies by the present inventors, it was found that the distance La should be set to 16 mm or less (that is, the spindle load F should be reduced), as shown in the results of Examples 2 to 4 to be described later. In addition, it was independently found that both high efficiency and good reliability can be further improved by using a lubricating oil 180 that has a low viscosity and contains a high molecular weight component (Figs. 6 and 7 reference).

That is, if a method of simply reducing the viscosity of the lubricating oil 180 is adopted, the wear or seizure of the main shaft 124 and the main bearings 134 cannot be effectively prevented or suppressed. It was considered unsuitable for ensuring the quality of the compressor 100 .

However, as described above, the present inventors found that the main shaft load F can be reduced by setting the distance La of the refrigerant compressor 100 to 16 mm or less. , so that it is possible to use lubricating oil 180 of relatively low viscosity. Furthermore, by using lubricating oil 180 that contains a low-viscosity and high-molecular-weight component, it is possible to form a better oil film, so that it is possible to achieve both high efficiency and good reliability. It has also become clear that the effect can be further improved.

In particular, when the refrigerant compressor 100 is operating at a low speed, the sliding environment of the main shaft sliding portion becomes severe, and if the lubricating oil 180 has a low viscosity, it becomes difficult to form a good oil film. On the other hand, according to the present disclosure, by setting the distance La to 16 mm or less to reduce the main shaft load F, even the low-viscosity lubricating oil 180 can easily form a good oil film during low-speed operation. can do. This makes it possible to effectively suppress or avoid wear or seizure of the main shaft 124 and the main bearing 134 .

The upper limit of the operating rotation speed during low-speed operation of the refrigerant compressor 100 is not particularly limited, and can be appropriately set according to the specific operating rotation speed range in the operating performance of the refrigerant compressor 100 . For example, rpms below the middle value of a specific range of operating rpms can be defined as relatively low operating rpms.

In the present disclosure, as described above, an example of a general operating rotation speed is in the range of 17 to 75 rps. , the efficiency (coefficient of performance) of the refrigerant compressor 100 can be significantly improved by setting the distance La to 16 mm or less even at an operating rotation speed of 35 rps or less. Therefore, in the present disclosure, low speed operation can be defined as operation at an operating speed of 35 rps or less.

Furthermore, according to a comparison of the results of Examples 3, 4 and Comparative Example, the coefficient of performance improved when the operating rotation speed decreased to 30 rps, 25 rps, 20 rps, and 17 rps compared to when the operating rotation speed was 35 rps. It is confirmed that the degree is equal or higher. Therefore, in the present disclosure, the upper limit of the operating rotation speed during low speed rotation can be appropriately set based on the results of Examples 3 and 4 (see FIG. 7). Thus, in the present disclosure, even during low-speed operation, the main shaft sliding portion can have a low coefficient of friction and good wear resistance, so the efficiency and reliability of the refrigerant compressor 100 can be improved. can be made better.

Here, in the present embodiment, as shown in FIGS. 1 and 2, an eccentric shaft 122 is provided on the upper portion (upper end) of the main shaft 124, and the piston 140 is attached to the eccentric shaft 122 through a connecting means 142. The piston 140 is inserted reciprocatingly in a horizontally arranged compression chamber 133 . That is, in the present embodiment, piston 140 and compression chamber 133 are positioned at the upper portion within refrigerant compressor 100 . However, the configuration of the refrigerant compressor 100 according to the present disclosure is not limited to this.

For example, although not shown, the eccentric shaft 122 may be provided at the lower portion (lower end) of the main shaft 124 so that the piston 140 and the compression chamber 133 may be positioned at the lower portion within the refrigerant compressor 100 . In this case, the distance L is the distance between the axial center of the compression chamber 133 and the upper end of the sliding surface, and the distance La is the distance between the axial center of the compression chamber 133 and the lower end of the sliding surface.

Alternatively, in the present embodiment, as shown in FIG. 1, crankshaft 120 extends in the vertical direction (longitudinal direction) of refrigerant compressor 100, so main shaft 124 and eccentric shaft 122 also extend in the vertical direction. However, the configuration of the refrigerant compressor 100 according to the present disclosure is not limited to this. Instead, it may be unevenly distributed on one side in the horizontal direction. In this case, both ends of the sliding surface serving as the reference for the distance L and the distance La are not vertically positioned but horizontally positioned.

Therefore, in the present disclosure, the end on the side of the compression chamber 133 (or the eccentric shaft 122) on the sliding surface of the main bearing 134 is defined as a first end, and the end on the opposite side is defined as a second end. Therefore, the distance L can be defined as the distance between the axial center of the compression chamber 133 and the second end of the sliding surface of the main bearing 134 , and the distance La can be defined as the sliding distance between the axial center of the compression chamber 133 and the main bearing 134 . It can be defined as the distance from the first end of the moving surface. In this embodiment (example shown in FIG. 1 or 2), the upper end 138 of the sliding surface is the first end, and the lower end 139 of the sliding surface is the second end.

In addition, in the present disclosure, the crankshaft 120 (the main shaft 124 and the eccentric shaft 122) can be defined as the first direction, for example. In this embodiment (example shown in FIG. 1 or 2), the vertical direction is the first direction and the horizontal direction is the second direction. Therefore, the reciprocating direction of the piston 140 and the arrangement direction of the compression chamber 133 (the axial direction of the compression chamber 133) are the second direction. When the crankshaft 120 extends horizontally, the horizontal direction is the first direction and the vertical direction is the second direction.

[Constitution of lubricating oil]
Next, a low-viscosity lubricating oil containing a high molecular weight component, which is particularly preferably used as the lubricating oil 180 in the refrigerant compressor 100 according to the present disclosure, will be specifically described. In the present disclosure, the lubricating oil 180 is not limited to a low-viscosity lubricating oil containing a high-molecular-weight component. Therefore, in the following description, a low-viscosity lubricating oil containing a high-molecular-weight component is referred to as a “suitable lubricating oil” for convenience of explanation. ”.

In the present embodiment, lubricating oil suitable for use as lubricating oil 180 has a kinematic viscosity at 40° C. of 1 mm ² /S to 7 mm ² /S. It has a molecular weight of 150 to 400 and contains 0.5% by mass or more of a component having a relatively large molecular weight, that is, a high molecular weight component having a mass molecular weight of 500 or more. The specific material of the suitable lubricating oil is not particularly limited, and typically, for example, at least one oily substance selected from the group consisting of mineral oil, alkylbenzene oil, and polyalkylene glycol oil is preferably used. can be done.

The suitable lubricating oil used in the present embodiment may originally contain a high molecular weight component, or may have a structure in which an oily substance corresponding to the high molecular weight component is added so as to be 0.5% by mass or more. There may be. Examples of the former include, for example, mineral oil. When preparing (manufacturing) a suitable lubricating oil by refining unrefined or partially refined raw mineral oil, the refining conditions or refining method of the raw material oil should be adjusted so that 0.5% by mass or more of high molecular weight components remain. Just do it. As an example of the latter, for example, mineral oil, alkylbenzene oil, or polyalkylene glycol oil is used as the "main component" of a suitable lubricating oil, and an oily substance that becomes a high molecular weight component is added as an "additive component" to this main component. things can be mentioned.

The average mass molecular weight of the lubricating oil suitable for use in the present embodiment may be within the range of 150 to 400 as described above. If the average mass molecular weight of the suitable lubricating oil is within this range, the range of kinematic viscosity at 40 ° C. described above can be satisfactorily realized, and when the high molecular weight component is contained at 0.5% by mass or more, the distance La When it is set to 16 mm or less, it becomes possible to form a suitable oil film in the main shaft sliding portion (the sliding portion between the main shaft 124 and the main bearing 134). The average weight molecular weight of suitable lubricating oils may also be in the range of 200-300. If the average mass molecular weight of the suitable lubricating oil is within this range, it becomes easier to form a suitable oil film on the main shaft sliding portion when the distance La is set to 16 mm or less, depending on various conditions.

When the preferred lubricating oil has a structure in which a high-molecular-weight component is added to the main component, the specific material or type of the high-molecular-weight component is not particularly limited, as long as it is an oily substance with a mass molecular weight of 500 or more. good. For example, when the main component is mineral oil, the same mineral oil may be used as the high molecular weight component, alkylbenzene oil, polyalkylene glycol oil, or other oily substance may be used. may

Although the method for measuring the average mass molecular weight of the suitable lubricating oil and the mass molecular weight of the high molecular weight component is not particularly limited, in the present disclosure, standard polystyrene conversion by the GPC (Gel Permeation Chromatography) method used in Example 2 described later. be able to. That is, the average mass molecular weight (weight average molecular weight) of a suitable lubricating oil may be measured as a polystyrene-equivalent weight (mass) average molecular weight by the GPC method. In addition, whether the mass molecular weight of the high molecular weight component is 500 or more is determined by measuring a molecular weight distribution graph showing the relationship between the differential molar mass distribution and the mass molecular weight by the GPC method, and whether or not there is a peak with a mass molecular weight of 500 or more. You can judge by

The content of the high-molecular-weight component in the preferred lubricating oil used in the present embodiment may have a lower limit of 0.5% by mass, and the upper limit thereof does not affect at least the functions or effects of the preferred lubricating oil. It is not particularly limited as long as it does not affect. According to Example 2 below (see FIG. 6B), the preferred lubricating oil contains at least 0.5 wt. This alone improves the coefficient of performance (COP) of the refrigerant compressor 100 .

Further, according to Example 2 (see FIG. 6B) described later, a preferable upper limit of the content of the high molecular weight component is 7.0% by mass or less, and more preferably 6.0% by mass or less. and more preferably 5.0% by mass. The coefficient of performance is improved even when the high molecular weight component exceeds 7.0% by mass, compared with the case where the suitable lubricating oil does not contain the high molecular weight component (0% by mass), but it exceeds 7.0% by mass Since there is a possibility that the effect of improving the coefficient of performance commensurate with the content of the high molecular weight component cannot be obtained, in the present embodiment, the upper limit of the content of the high molecular weight component is 7.0% by mass or less. can.

In addition, according to the examples described later, when the coefficient of performance in the range where the content of the high molecular weight component exceeds 6.0% by mass is compared with the coefficient of performance in the range of 6.0% by mass or less, the coefficient of performance is 6. A range of 0.0% by mass or less shows a better coefficient of performance. Therefore, in the present embodiment, the preferred upper limit of the content of the high molecular weight component is 6.0% by mass or less. Furthermore, according to the examples described later, the content of the high molecular weight component is The coefficient of performance shows a maximum value around 2.0 to 2.5% by mass, and even around 5.0% by mass, the coefficient of performance is about the same as the lower limit of 0.5% by mass. Therefore, in the present embodiment, the more preferable upper limit of the content of the high molecular weight component can be 5.0% by mass or less.

Therefore, in the present embodiment, the preferable range of the content of the high molecular weight component in the suitable lubricating oil is 0.5% by mass to 7.0% by mass, and a more preferable range is The range of 0.5% by mass to 6.0% by mass can be cited, and a more preferable range is 0.5% by mass to 5.0% by mass. Note that depending on the conditions of the refrigerant compressor 100 or the shaft portion to be lubricated, the maximum value of the coefficient of performance may shift to the side where the content of the high-molecular-weight component decreases or increases. In this case, the upper limit of the content of the high molecular weight component can be set to a value exceeding 7.0% by mass or a value less than 0.5% by mass.

If the content of the high-molecular-weight components in the suitable lubricating oil is within the above range, it is basically determined that the average mass molecular weight of the suitable lubricating oil falls within the range of 150-400. That is, if the ratio of the high molecular weight component contained in the suitable lubricating oil is within the above range, the high molecular weight component has almost no effect on the increase in the average mass molecular weight when viewed in the entire suitable lubricating oil (preferred the average mass molecular weight of the lubricating oil does not exceed 400). Therefore, the upper limit of the content of the high-molecular-weight component in the preferred lubricating oil can be set within a range that does not affect the functions of the preferred lubricating oil and does not excessively increase the average mass molecular weight.

In the present embodiment, the reason why the coefficient of performance of the refrigerant compressor 100 improves when the suitable lubricating oil contains a high-molecular-weight component is the result of Examples 2 and 4 described later (see FIGS. 6B and 7). ), even if the suitable lubricating oil has a low viscosity (kinematic viscosity at 40°C is within the range of 1 mm ² /S to 7 mm ² /S), the high molecular weight component contributes to the formation of a good oil film on the sliding part. This is thought to be because That is, when the main shaft 124 slides while being supported by the main bearings 134, the lubricating oil on the outer peripheral surface (sliding surface) of the main shaft 124, which constitutes the main shaft sliding portion, does not flow along with the entire flow of the suitable lubricating oil generated in the main shaft sliding portion. It is believed that a high molecular weight component can be present on the inner peripheral surface (sliding surface) of the main bearing 134 and on the sliding surface of the main bearing 134, thereby forming a good oil film with a suitable lubricating oil.

In the present embodiment, only one type of oily substance may be used as the suitable lubricating oil, or two or more types may be used in combination. The combination of two or more types of oily substances here means, for example, not only the combination of two or more different oily substances corresponding to mineral oil, but also, for example, one or more oily substances corresponding to mineral oil and alkylbenzene oil. (Or one or more oily substances corresponding to polyalkylene glycol oil) may be combined.

Further, when the suitable lubricating oil is one in which a high molecular weight component is added as an additive component to the main component, for example, one type of oily substance is used as the main component, and an oily substance different from the main component is used as the high molecular weight component. One type of substance may be used. Alternatively, two or more oily substances may be used as the main component and one oily substance may be used as the high molecular weight component, or one oily substance may be used as the main component and two or more oily substances may be used as the high molecular weight component. Substances may be used. Alternatively, two or more types of mixtures of oily substances in which a high molecular weight component is added to the main component may be further mixed.

In the present embodiment, the oily substance itself is not particularly limited, but at least one of mineral oil, alkylbenzene oil, and ester oil may be used as the main component or the high molecular weight component (or both) as the oily substance. The suitable lubricating oil thus obtained can satisfactorily achieve the effect of reducing the friction coefficient of the shaft portion even when the sliding area is reduced.

The physical properties of the suitable lubricating oil (oily substance or lubricating oil composition) used in the present embodiment are not particularly limited except for the kinematic viscosity at 40° C. described above. Distillation characteristics of 0.1% or more at a distillation temperature of 300° C. and an end point of 440° C. or more can be mentioned. The method for measuring the distillation characteristics is not particularly limited, but in the present embodiment, a method for measurement according to JIS K2254:1998 Petroleum products-Distillation test method or JIS K2601:1998 Crude oil test method is used.

In the sliding part consisting of the shaft part and the bearing part, heat is generated due to friction between the sliding surfaces during sliding, but in the early stage of the friction, a momentary high temperature called flash temperature may occur. Are known. The outer peripheral surface of the shaft portion and the inner peripheral surface of the bearing portion are configured as smooth sliding surfaces in order to achieve good slidability. However, even if the sliding surface is macroscopically smooth, microscopically there are minute protrusions. During sliding, fine protrusions on one sliding surface repeatedly adhere to and break off from the other sliding surface. A momentary high temperature is generated when the heat energy released when the fine protrusion is broken is concentrated, and this momentary high temperature is called a flash temperature.

For example, Reference 1: Japanese Unexamined Patent Publication No. 2006-097096 discloses a carburized or carbonitrided bearing steel part. It is described that seizure occurs when it exceeds . It is also known that the flash temperature at the sliding portion reaches several hundred degrees. It was determined that the following conditions were important.

Therefore, in the preferred lubricating oil (oil substance or lubricating oil composition) used in the present embodiment, the distillation characteristic is such that the distillation fraction (volume fraction) at a distillation temperature of 300 ° C. is 0.1% It is preferable that the end point is 440° C. or higher. When the distillation property of the preferred lubricating oil satisfies this condition, even if a flash temperature of 300° C. or higher occurs in the sliding portion, evaporation of the oil film or the like by the preferred lubricating oil can be effectively suppressed or prevented. Therefore, even if the preferred lubricating oil contains a high molecular weight component and has a low viscosity, and the temperature of the sliding portion increases due to the reduction of the sliding area, the oil film of the preferred lubricating oil can be more stably formed. can be formed.

The lubricating oil suitable for use in the present embodiment may be a low-viscosity oily substance containing a high-molecular-weight component, and various additives may be added to this oily substance. In other words, the suitable lubricating oil used in this embodiment may be a lubricating oil composition containing components other than oily substances. In addition, as described above, the oily substance used as a suitable lubricating oil may be one type or two or more types, but even when two or more types of oily substances are used, the "lubricating oil composition" may be defined as Alternatively, when two or more types of oily substances are used, it may be defined as "mixed oil", and when it contains components other than oily substances, it may be defined as "lubricating oil composition".

When the suitable lubricating oil used in the present embodiment is a lubricating oil composition containing components (other components) other than oily substances, specific other components are not particularly limited, but typically Additives known in the field of general lubricating oils can be mentioned. In particular, in the present embodiment, the suitable lubricating oil preferably contains an oiliness agent. By adding an oily agent to the suitable lubricating oil, an oil film of the suitable lubricating oil is likely to be formed on the sliding surface of the sliding portion. As a result, it is possible to more preferably achieve low friction in the sliding portion.

Specific types of oily agents are not particularly limited, but representative examples include higher fatty acids, higher alcohols, esters (ester compounds), ethers, amines, amides, and metallic soaps. These oily agents may be used alone or in combination of two or more. The amount of the oiliness agent to be added is not particularly limited, but may be, for example, within the range of 0.01 to 1% by weight.

In the present embodiment, an ester-based compound can be mentioned as a more preferable oiliness agent. The ester-based compound may be a compound having an ester structure obtained by reacting an alcohol and a carboxylic acid. The alcohol may be a monohydric alcohol or a dihydric or higher polyhydric alcohol. Similarly, the carboxylic acid may be a monocarboxylic acid, a dicarboxylic acid, or a tricarboxylic acid (which may have 4 or more carboxy groups). In general, commercially available ester-based oiliness agents can be suitably used.

The preferred lubricating oil used in the present embodiment is a low-viscosity lubricating oil containing a high-molecular-weight component as described above. The ability to form can be further improved. As described above, the preferred lubricating oil used in the present embodiment contains a high molecular weight component, so the high molecular weight component is present on the sliding surfaces of the main shaft 124 and the main bearing 134 that form the sliding portions. It is considered that a better oil film can be formed by Furthermore, since the suitable lubricating oil contains an oily agent, the oily agent is adsorbed on the sliding surfaces of the main shaft 124 and the main bearing 134, thereby further facilitating the formation of an oil film by the suitable lubricating oil (lubricating oil composition). It is considered that

In particular, if the oiliness agent is an ester compound, the oiliness agent will have an ester bond. Therefore, the polarity derived from this ester bond makes it easier for the oil film of the suitable lubricating oil (lubricating oil composition) to adhere to the sliding portion (improves the adhesion of the oil film). As a result, the ability of the suitable lubricating oil to form an oil film can be further improved, so that the coefficient of friction can be further reduced, and the low friction of the sliding portion can be more suitably achieved.

The suitable lubricating oil used in the present embodiment may contain, as an additive, a sulfur-based slidability improver in addition to the oily agent described above. Examples of the sulfur-based slidability modifier include those that can react with the material used for the shaft portion such as the main shaft 124 (shaft portion material) and sulfur. Therefore, the slidability modifier may be sulfur itself or a sulfur compound that contains sulfur and is capable of reacting with the shaft portion material.

In the present embodiment, since an iron-based material is used as the material of the shaft portion, the sulfur compounds that can be used as the slidability modifier include sulfurized olefins and sulfide-based compounds (e.g., dibenzyl (di)sulfide (DBDS) ), etc.), xantate, thiadiazole, thiocarbonate, sulfurized fat, sulfurized ester, dithiocarbamate, sulfurized terpene, and the like.

The content of the sulfur-based slidability modifier in the suitable lubricating oil is not particularly limited, but the slidability modifier is preferably added to the suitable lubricating oil so that the sulfur element weight is 100 ppm or more. should be added to The upper limit of the amount of the slidability modifier to be added is not particularly limited as long as it does not affect the physical properties of the suitable lubricating oil (lubricating oil composition) (for example, 1000 ppm or less).

The preferred lubricating oil used in the present embodiment is a low-viscosity lubricating oil containing a high-molecular-weight component as described above. If the lubricating oil composition is such that the slidability modifier can improve the wear resistance of the sliding surface. Therefore, even in a state where the sliding area is reduced, it is possible to more preferably achieve low friction of the sliding portion.

The lubricating oil suitable for use in the present embodiment may contain known extreme pressure additives as additives in addition to the above-described oiliness agent and sliding property modifier. As a specific extreme pressure additive, a known one can be suitably used, and it is not particularly limited. compound etc. can be mentioned. These extreme pressure additives may be added to the lubricating oil composition (preferred lubricating oil) singly or in combination of two or more.

Among these extreme pressure additives, phosphorus compounds can be preferably used. Typical phosphorus-based compounds include tricresyl phosphate (TCP), tributyl phosphate (TBP), and triphenyl phosphate (TPP), among which TCP can be used more preferably. By adding a phosphorus-based extreme pressure additive to a suitable lubricating oil in addition to a sulfur-based slidability modifier, it is possible to achieve good wear reduction and the like in the main shaft sliding portion.

The amount of the extreme pressure additive to be added to the lubricating oil composition is not particularly limited. 0.5 to 8.0% by weight, preferably 1 to 3% by weight.

The preferred lubricating oil used in the present embodiment is a low-viscosity lubricating oil containing a high-molecular-weight component as described above. If it is an oil composition, the wear resistance of the sliding surface can be improved by the extreme pressure additive. In particular, if both the slidability modifier and the extreme pressure additive are contained, the synergistic effect thereof can further effectively reduce wear on the sliding surface. Therefore, even in a state where the sliding area is reduced, it is possible to more preferably achieve low friction of the sliding portion.

In addition, in the present embodiment, various known additives may be added to the suitable lubricating oil in addition to the oiliness agent, slidability modifier and extreme pressure additive. Various additives known in the field of general lubricating oils can be suitably used as such additives. agents, corrosion inhibitors, or dispersants.

In other words, in the present embodiment, the lubricating oil suitable for use in the refrigerant compressor 100 is a low-viscosity oily substance containing a high-molecular-weight component (either one type or a mixed oil of two or more types). It may be a lubricating oil composition in which an oily agent is added to an oily substance (consisting of an oily substance and an oily agent). Another preferred example is a lubricating oil composition The article may contain additives such as slidability modifiers, extreme pressure additives, or both.

Thus, in the refrigerant compressor 100 according to the present disclosure, the compression element 106 extends vertically and includes a crankshaft 120 having a main shaft 124 and an eccentric shaft 122 , the main shaft 124 being supported by the main bearing 134 . , a thrust bearing (for example, a thrust ball bearing 210) is provided on the thrust surface 136 of the main bearing 134, the distance between the axial center of the compression chamber 133 and the lower end 139 of the sliding surface of the main bearing 134 is L, and the compression chamber 133 and the upper end 138 of the sliding surface of the main bearing 134, the distance La is 16 mm or less when the distance L is in the range of 38 mm to 51 mm.

With such a configuration, in a closed refrigerant compressor having a thrust bearing, when the distance L that affects the overall height is specified within a predetermined range, the axial center of the compression chamber 133 and the sliding surface of the main bearing 134 The upper limit of the distance La to the upper end 138 is specified as 16 mm. As a result, the flange portion 128, which contributes to the stability of the eccentric shaft 122, can be prevented from being excessively thin, and an increase in overall height can be avoided. load can be reduced. As a result, the efficiency can be further improved without increasing the overall height of the hermetic refrigerant compressor. Moreover, since the flange portion 128 is not excessively thinned, it is possible to achieve high efficiency and good reliability.

(Embodiment 2)
In Embodiment 2, an example of a freezing/refrigerating apparatus including refrigerant compressor 100 described in Embodiment 1 will be specifically described with reference to FIG.

The refrigerant compressor 100 according to the present disclosure can be widely and suitably used in various devices (freezer/refrigerator) having a refrigeration cycle or substantially equivalent configuration. Specifically, for example, refrigerators (household refrigerators, commercial refrigerators), ice machines, showcases, dehumidifiers, heat pump water heaters, heat pump washer/dryers, vending machines, air conditioners, air compressors, etc. Examples include, but are not particularly limited to. In Embodiment 2, as an example of application of the refrigerant compressor 100 according to the present disclosure, an article storage device shown in FIG. 4 will be cited to describe the basic configuration of a freezing/refrigerating device.

As shown in FIG. 4, the freezing/refrigerating apparatus according to Embodiment 4 includes a main body 301, a partition wall 304, a refrigerant circuit 305, and the like. The main body 301 is composed of a heat-insulating box body, a door body, and the like. The box body has a configuration in which one surface is open, and the door body is configured to open and close the opening of the box body. The interior of the main body 301 is partitioned into an article storage space 302 and a machine room 303 by a partition wall 304 . A fan (not shown) is provided in the storage space 302 . Note that the interior of the main body 301 may be partitioned into spaces other than the storage space 302 and the machine room 303 .

The refrigerant circuit 305 has a configuration for cooling the storage space 302, and includes the refrigerant compressor 100 described in the first embodiment, a radiator 307, a pressure reducing device 308, and a heat absorber 309. It is configured to be connected by piping to That is, the refrigerant circuit 305 is an example of a refrigeration cycle using the refrigerant compressor 100 according to the present disclosure.

As described above, the refrigerant gas 181 such as R600a is sealed in the refrigerant compressor 100 (inside the sealed container 102). It is enclosed at a relatively low temperature so that Although the specific type of refrigerant gas 181 is not particularly limited, a hydrocarbon-based refrigerant with a low global warming potential such as R600a can be preferably used.

A heat absorber 309 of the refrigerant circuit 305 is arranged within the storage space 302 . The cooling heat of the heat absorber 309 is agitated so as to circulate within the storage space 302 by an air blower (not shown), as indicated by dashed arrows in FIG. The inside of the storage space 302 is thereby cooled.

Thus, the freezing/refrigerating apparatus according to the second embodiment is equipped with the refrigerant compressor 100 according to the first embodiment. In the refrigerant compressor 100 according to the present disclosure, the thrust bearing is provided on the thrust surface 136 of the main bearing 134 as described above. When the distance L between the axial center of the compression chamber 133 and the sliding surface upper end 138 of the main bearing 134 (the side close to the compression chamber 133 The distance La from the (first end of the) is 16 mm or less.

Since the refrigerant compressor 100 according to the present disclosure has such a configuration, an increase in the overall height of the refrigerant compressor 100 is avoided without thinning the flange portion 128 that contributes to the stability of the eccentric shaft 122. In addition, the load on the main shaft 124 can be reduced without applying special treatment to the sliding surface. As a result, the efficiency can be further improved without increasing the overall height of the refrigerant compressor 100 . Therefore, a freezer/refrigerator equipped with such a refrigerant compressor 100 can reduce power consumption and have high reliability.

The present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to these. Various changes, modifications and alterations can be made by those skilled in the art without departing from the scope of the invention.

(Example 1)
As described above, in the present disclosure, the main shaft load F of the refrigerant compressor 100 can be obtained based on the following formula (2). However, as described above, Fa in equation (2) is the load from the piston 140 (piston load Fa), La is the distance between the axial center of the compression chamber 133 and the sliding surface upper end 138, and L is the compression It is the distance between the axis of the chamber 133 and the lower end 139 of the sliding surface.
F=Fa×{1+La/(L−La)} (2)
Therefore, assuming a reciprocating compressor: TKD91E (product name, manufactured by Panasonic Corporation) as the refrigerant compressor 100 of the present embodiment, the distance La is changed within the range of 10 mm to 20 mm based on the above equation (2). The change in the main shaft load F when the piston load Fa is applied is compared with the simulation result of the inclination angle of the eccentric shaft 122 when the piston load Fa is applied. The results are shown in the graph of FIG.

In the graph of FIG. 5, the solid line indicates changes in the main shaft load F, and the dotted line indicates changes in the inclination angle of the eccentric shaft 122. As shown in FIG. In the graph of FIG. 5, the horizontal axis represents the change in the distance La (unit: mm), and the vertical axis represents the change (relative value) in the main shaft load F or the change (relative value) in the inclination angle of the eccentric shaft 122. be. For the simulation of the inclination angle of the eccentric shaft 122, CAE (computer aided engineering) software NX series (manufactured by Siemens PLM Software), which is commercially available structural analysis software, was used.

As is clear from the correlation graph in FIG. 5, the spindle load F is expressed by the above equation (2), so the spindle load F increases as the distance La increases. However, if the distance La is reduced without changing the distance L, the thickness of the flange portion 128 will inevitably be reduced (thinned). When the flange portion 128 becomes thin, the eccentric shaft 122 is inclined with respect to the main shaft 124 . Therefore, as shown in FIG. 5, the inclination angle of the eccentric shaft 122 that receives the piston load Fa increases as the distance La decreases.

In refrigerant compressor 100 , piston 140 is connected to eccentric shaft 122 via connecting means 142 , and piston 140 is inserted into compression chamber 133 . When the inclination angle of the eccentric shaft 122 becomes excessively large, the posture of the piston 140 connected to the eccentric shaft 122 deteriorates. If the posture of the piston 140 deteriorates during the operation of the refrigerant compressor 100, abrasion or the like occurs between the cylinder 132 and the piston 140, so there is a risk that the reliability of the refrigerant compressor 100 cannot be sufficiently ensured.

On the other hand, it can be seen that when the distance La increases, the inclination angle of the eccentric shaft 122 asymptotically approaches a predetermined value and does not change significantly even when the piston load Fa is applied. In this way, when it can be assumed that the inclination angle is substantially constant at a predetermined value, it can be said that the posture of piston 140 connected to eccentric shaft 122 is favorable during operation of refrigerant compressor 100 . Therefore, it is judged that good reliability can be ensured in the refrigerant compressor 100 .

From the results shown in FIG. 5, the correlation between the change in the main shaft load F and the change in the inclination angle of the eccentric shaft 122 can be divided into region I, region II, and region III in FIG.

In region I, since the inclination angle of the eccentric shaft 122 is small, the reliability of the refrigerant compressor 100 can be sufficiently ensured. be.

In region II, the inclination angle of eccentric shaft 122 is relatively large compared to region I, but the reliability of refrigerant compressor 100 can be sufficiently ensured. Moreover, in region II, the main shaft load F can be made relatively smaller than in region I, so efficiency of the refrigerant compressor 100 can be improved.

In region III, since the main shaft load F is smaller than in region II, the efficiency of the refrigerant compressor 100 can be improved. Depending on the situation, the reliability of the refrigerant compressor 100 may not be sufficiently ensured.

As described above, based on the results shown in FIG. 5, in the refrigerant compressor 100 according to the present disclosure, in order to achieve both reliability and high efficiency, changes in the main shaft load F and the eccentric shaft 122 Region I, in which high efficiency cannot be achieved, is omitted from the correlation with the change in tilt angle. Therefore, the upper limit of the distance La can be set to 16 mm.

Also, in region III, there is a possibility that sufficient reliability cannot be ensured depending on various conditions, so region II is determined to be a suitable range. Therefore, the preferred range of the distance La can be set to 12 mm to 16 mm (12 mm≦La≦16 mm).

(Example 2)
As the refrigerant compressor 100 (see Example 1) of the present embodiment, the distance La is set to 15.8 mm, and as the lubricating oil 180, a low viscosity containing a high molecular weight component having a mass molecular weight of 500 or more mineral oil (lubricating oil 180 of this example, the preferred lubricating oil described above) was used. Specifically, the kinematic viscosity at 40° C. of the lubricating oil 180 of this embodiment is 2.7 mm ² /S, and both the main component and the high molecular weight component are mineral oils.

The molecular weight distribution of Lubricating Oil 180 having a high molecular weight component content of 2.0% by mass was measured by the GPC method. The results are shown in FIG. 6A. In the molecular weight distribution graph of FIG. 6A, the vertical axis is differential molar mass distribution (dW/dlogM) and the horizontal axis is mass molecular weight. In addition, the conditions of the GPC method are as follows: a differential refractive index detector RI as a detector, a column having a diameter of 6.0 mm and a length of 15 cm, tetrahydrofuran (THF) as a solvent, and monodisperse polystyrene as a standard sample, The flow rate was 0.45 mL/min and the column temperature was 40°C.

As shown in FIG. 6A, in the lubricating oil 180 used in this example, peaks of the high-molecular-weight components indicated by block arrows are observed along with peaks of the main component having relatively low-molecular-weight. Although not shown, no peak of the high molecular weight component is observed in the conventional lubricating oil containing no high molecular weight component.

In addition, the coefficient of performance of the refrigerant compressor 100 was evaluated by changing the content of the high molecular weight component in the lubricating oil 180 of this example within the range of 0% by mass to about 8% by mass. The results are shown in FIG. In the graph of FIG. 6B, the vertical axis is the coefficient of performance, and the horizontal axis is the content of the high molecular weight component. The coefficient of performance (COP) is the ratio of refrigerating capacity (refrigerating capacity/input) to energy consumption (input).

As is clear from the results shown in FIG. 6B, in the refrigerant compressor 100 using the lubricating oil 180 of the present embodiment, the coefficient of performance is reduced by containing at least 0.5% by mass of the high molecular weight component in the lubricating oil 180. It turns out that it can reduce satisfactorily.

(Example 3)
As the refrigerant compressor 100 (see Example 1) of this embodiment, the distance La is set to 15.8 mm as in Example 2, and the conventional lubricating oil 180 (manufactured by JXTG Nippon Oil & Energy Corporation, The product name FREOL S3) was used. The coefficient of performance was evaluated in the same manner as in Example 2 while changing the operating speed of the refrigerant compressor 100 to 37 rps, 27 rps, and 17 rps. The results are shown graphically in FIG. 7 with square symbols. In the graph of FIG. 7, the vertical axis is the coefficient of performance (relative value) and the horizontal axis is the operating speed (unit: rps) of the refrigerant compressor.

(Example 4)
As the refrigerant compressor 100 (see Example 1) of this embodiment, the distance La is set to 15.8 mm as in the second embodiment. A preferred lubricating oil (see Example 2 and Figure 6A) with a viscosity of 7 ^mm2 /S and a high molecular weight content of 2.0% by weight was used. The coefficient of performance was evaluated in the same manner as in Example 3 except for these. The results are shown graphically with triangular symbols in FIG.

(Comparative example)
As the refrigerant compressor of the comparative example, a conventional one having a distance La exceeding 16 mm was used, and a conventional lubricating oil was used as in the third embodiment. The coefficient of performance was evaluated in the same manner as in Example 3 except for these. The results are shown graphically with circular symbols in FIG.

(Comparison of Examples 3 and 4 and Comparative Example)
As shown in FIG. 7, in the refrigerant compressors 100 of Examples 3 and 4, the coefficient of performance (compressor efficiency) is significant at an operating speed of at least 35 rps or less compared to the conventional refrigerant compressor of the comparative example. is found to rise to A comparison between the comparative example and Example 3 reveals that the difference in the coefficient of performance tends to widen as the operating speed decreases from 27 rps.

Furthermore, as is clear from the comparison of Examples 3 and 4, the lubricating oil 180 is not the conventional one (Example 3), but has a low viscosity and contains a high molecular weight component (Example 4). It can be seen that the coefficient of performance is further increased by using In particular, in the comparison of Examples 3 and 4, it can be seen that the difference in the coefficient of performance widens as the operating rotation speed decreases from 27 rps.

It should be noted that the present invention is not limited to the description of the above embodiments, and various modifications are possible within the scope of the claims, and different embodiments and multiple modifications are disclosed respectively. Embodiments obtained by appropriately combining the above technical means are also included in the technical scope of the present invention.

Also, many modifications and other embodiments of the invention will be apparent to those skilled in the art from the above description. Accordingly, the above description is to be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. Substantial details of construction and/or function may be changed without departing from the spirit of the invention.

As described above, according to the present invention, it is possible to further improve the efficiency while maintaining the high reliability of the hermetic refrigerant compressor. Therefore, the present invention can be widely applied to various equipment using a refrigeration cycle.

100: Hermetic refrigerant compressor 102: Hermetic container 104: Electric element 106: Compression element 108: Compressor body 120: Crankshaft 122: Eccentric shaft 124: Main shaft 125: Oil supply mechanism 126: Sliding surface 127: Non-sliding surface 128: Flange 130: Cylinder block 132: Cylinder 133: Compression chamber 134: Main bearing 136: Thrust surface 137: Tubular extension 138: Upper end (first end) of sliding surface
139: Slide surface lower end (second end)
140: Piston 142: Connecting means 150: Stator 152: Rotor 180: Lubricating oil 181: Refrigerant gas 190: Suspension spring 202: Upper race 204: Ball (rolling element)
205: retainer 206: lower race 210: thrust ball bearing (thrust bearing)
301: Main body 302: Storage space 303: Machine room 304: Partition wall 305: Refrigerant circuit 307: Radiator 308: Pressure reducing device 309: Heat absorber

Claims (14)

A closed container that stores lubricating oil, an electric element housed in the closed container, and a compression element that is driven by the electric element and compresses a refrigerant,
The compression element is
a crankshaft having a main shaft and an eccentric shaft;
a cylinder block provided with a compression chamber;
a piston reciprocally inserted into the compression chamber;
connecting means for connecting the piston and the eccentric shaft;
a main bearing that supports the main shaft;
a thrust bearing provided on the thrust surface of the main bearing;
with
The crankshaft has a flange portion connecting the main shaft and the eccentric shaft,
The end of the sliding surface of the main bearing on the side of the compression chamber is defined as a first end, the end on the opposite side is defined as a second end, and the axial center of the compression chamber and the second end of the sliding surface of the main bearing. When L is the distance between and La is the distance between the axial center of the compression chamber and the first end of the sliding surface of the main bearing,
The distance La is 16 mm or less when the distance L is in the range of 38 mm to 51 mm,
Hermetic refrigerant compressor. The thrust bearing comprises a lower race positioned on the thrust surface, an upper race positioned opposite the lower race, and a plurality of rolling elements rollingly contacting therebetween,
characterized in that the rolling element is a ball,
The hermetic refrigerant compressor according to claim 1. characterized in that the thickness of the flange portion exceeds 4 mm,
The hermetic refrigerant compressor according to claim 1 or 2. The lubricating oil has a kinematic viscosity of 1 mm ² /S to 7 mm ² /S at 40 ° C.
The hermetic refrigerant compressor according to any one of claims 1 to 3. The lubricating oil has an average mass molecular weight of 150 to 400 and contains 0.5% by mass or more of a high molecular weight component,
The high molecular weight component is characterized in that its mass molecular weight is 500 or more,
The hermetic refrigerant compressor according to claim 4. The hermetic refrigerant compressor according to any one of claims 1 to 5, wherein the lubricating oil contains an oily agent. characterized in that the oily agent is an ester compound,
A hermetic refrigerant compressor according to claim 6 . The lubricating oil has a distillation fraction of 0.1% or more at a distillation temperature of 300 ° C. and an end point of 440 ° C. or more,
The hermetic refrigerant compressor according to claim 1 or 7. The lubricating oil contains a slidability modifier of 100 ppm or more when converted to sulfur element weight,
The hermetic refrigerant compressor according to any one of claims 1 to 8. The lubricating oil is characterized by containing a phosphorus-based extreme pressure additive,
The hermetic refrigerant compressor according to any one of claims 1 to 9. The lubricating oil is at least one selected from the group consisting of mineral oil, alkylbenzene oil, and ester oil,
The hermetic refrigerant compressor according to any one of claims 1 to 10. The electric element is inverter-driven at a plurality of operating frequencies,
The hermetic refrigerant compressor according to any one of claims 1 to 11. It is characterized by being operated at a rotation speed of 35 rps or less,
13. The hermetic refrigerant compressor of claim 12. A refrigerant circuit comprising: the hermetic refrigerant compressor according to any one of claims 1 to 13; do,
Refrigeration equipment.

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