Hermetically sealed refrigerant compressor, method for operating same, and freezing and refrigerating device using same

Abstract

The present invention provides a hermetic refrigerant compressor, comprising: a hermetic container; refrigerating machine oil which is stored in the sealed container and has a kinematic viscosity of 1.0 mm2 / s to 2.5 mm2 / s at 40 DEG C; a cylinder accommodated in the sealed container and forming a compression chamber; and a piston inserted inside the compression chamber so as to be capable of reciprocating. When the operating frequency is 16 r / s or more and 35 r / s or less, the average speed of the reciprocating motion of the piston is set to exceed 0.31 m / s.

Description

Technical Field

[0001] The present invention relates to a sealed refrigerant compressor used in a refrigerator, an air conditioner, etc., an operating method of the sealed refrigerant compressor, and a refrigeration device using the sealed refrigerant compressor. Background Art

[0002] In recent years, from the perspective of protecting the global environment, the input power of fossil fuels has been reduced, and the development of high-efficiency sealed refrigerant compressors has been promoted. In order to reduce the input power of sealed refrigerant compressors, reducing the operating frequency is an effective method.

[0003] On the other hand, regarding high efficiency, the coefficient of performance (COP) represented by refrigeration capacity / input power is an indicator of the efficiency of a sealed refrigerant compressor. In order to improve the coefficient of performance (COP), for example, the use of low-viscosity oil (refrigeration oil, lubricating oil) is proposed. For example, Patent Document 1 discloses a refrigerant compressor that achieves high efficiency by making the viscosity of the oil stored in a sealed container greater than VG3 and less than VG8.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application No. 2008-531896 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] Here, in recent years, in order to further improve the coefficient of performance (COP), research is being conducted to further reduce the viscosity of refrigeration oil. For example, in the refrigerant compressor disclosed in Reference 1, the viscosity of the oil (refrigeration oil) is, as mentioned above, in the range of VG3 to VG8, but in recent years, research has been conducted on the use of refrigeration oil below VG3. However, simply using refrigeration oil with a lower viscosity to further reduce sliding losses is not enough to achieve a further improvement in the coefficient of performance (COP).

[0009] The present invention has been made to solve such a problem, and its object is to provide a closed refrigerant compressor and an operating method thereof, and a refrigeration / refrigeration device using the same, which can use a refrigeration oil with a lower viscosity and achieve a better coefficient of performance (COP).

[0010] Technical solutions to solve problems

[0011] In order to solve the above problems, the sealed refrigerant compressor of the present invention is composed of: a sealed container; a refrigeration oil stored in the sealed container, and having a kinematic viscosity of 1.0 mm at 40°C; 2 / s~2.5mm 2 / s range; a cylinder body contained in the closed container and forming a compression chamber; and a piston inserted into the interior of the compression chamber in a reciprocating manner, when the operating frequency is greater than 16r / s and less than 35r / s, the average speed of the reciprocating motion of the piston can be set to exceed 0.31m / s.

[0012] According to the above structure, when the operating frequency of the sealed refrigerant compressor is 16 r / s or more and 35 r / s or less, the lower limit of the average speed of the reciprocating motion of the piston (the average piston speed) is set. Thus, even if the operating speed of the sealed refrigerant compressor is relatively low, the average piston speed can be relatively high. Therefore, as a refrigeration oil, even if a lower viscosity (kinematic viscosity at 40°C is set to 1.0 mm 2 / s~2.5mm 2 / s) can also form a good oil film between the high-speed reciprocating piston and the compression chamber. As a result, it is possible to effectively suppress the leakage of refrigerant gas from the piston and the compression chamber. Therefore, when low-viscosity oil is used as refrigeration oil, the coefficient of performance (COP) of the sealed refrigerant compressor can be further improved.

[0013] In addition, in order to solve the above-mentioned problems, the sealed refrigerant compressor of the present invention can also be constructed as follows: a sealed container; a refrigeration oil stored in the sealed container, and having a kinematic viscosity of 1.0 mm at 40°C; 2 / s~2.5mm 2 / s; a cylinder body housed in the closed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, wherein the ratio S / D of the stroke (S) of the reciprocating motion of the piston to the diameter (D) of the piston is in the range of 0.78 to 1.00.

[0014] According to the above structure, as a refrigeration oil, the kinematic viscosity at 40°C is 1.0 mm 2 / s~2.5mm 2 When using a low viscosity oil in the range of 1 / 20 / s, the above ratio S / D is set within a specified range. As a result, the stroke amount (S) can be relatively increased, and thus the average piston speed can be relatively increased. Therefore, the leakage of refrigerant gas can be well suppressed.

[0015] In addition, when the low-viscosity oil is used as the refrigeration oil, the piston diameter (D) can be relatively reduced by setting the ratio S / D within a predetermined range, thereby reducing the total area of ​​the gap between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder, thereby effectively suppressing the leakage of the refrigerant gas.

[0016] Furthermore, when the piston diameter (D) becomes relatively small, the compression load of the refrigerant gas on the piston can be reduced, thereby reducing the input power for reciprocating the piston.

[0017] Therefore, by setting the ratio S / D within a predetermined range, when low-viscosity oil is used as refrigeration oil, the coefficient of performance (COP) of the hermetic refrigerant compressor can be further improved.

[0018] In addition, in order to solve the above-mentioned problems, the sealed refrigerant compressor of the present invention can also be constructed as follows: a sealed container; a refrigeration oil stored in the sealed container, and having a kinematic viscosity of 1.0 mm at 40°C; 2 / s~2.5mm 2 / s; a cylinder body contained in the closed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, when the ratio L1 / D of the total length of the piston to the diameter of the piston (D) is in the range of 0.8 to 1.0, and the length of the area sealed in the compression chamber by the reciprocating motion of the piston is set as a sealing length (L2), the ratio L2 / L1 of the sealing length (L2) to the total length of the piston (L1) is in the range of 0.9 to 1.0.

[0019] According to the above structure, as a refrigeration oil, the kinematic viscosity at 40°C is 1.0 mm 2 / s~2.5mm 2 When using a low viscosity oil within the range of 1 / 200 rpm to 1 / 400 rpm, the above ratio L1 / D and ratio L2 / L1 are set within the specified range. As a result, the increase in sliding loss can be suppressed, and the sealing length (L2) can be relatively increased without excessively increasing the total length of the piston (L1). Therefore, between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder, the increase in sliding loss can be suppressed and the viscosity of the oil film can be increased.

[0020] In addition, the area sealed by the oil film of the refrigeration oil between the piston and the cylinder can be relatively increased, thereby further suppressing the leakage of the refrigerant gas.

[0021] Furthermore, when the seal length (L2) is increased, the posture of the piston reciprocating in the compression chamber can be stabilized. As a result, the increase in sliding loss can be further suppressed.

[0022] Therefore, by setting the ratio L1 / D and the ratio L2 / L1 within a predetermined range, when low-viscosity oil is used as refrigeration oil, the coefficient of performance (COP) of the sealed refrigerant compressor can be further improved.

[0023] In addition, the operating method of the sealed refrigerant compressor of the present invention is to solve the above-mentioned problem as long as the sealed refrigerant compressor comprises: a sealed container; a refrigeration oil stored in the sealed container, and having a kinematic viscosity of 1.0 mm at 40°C; 2 / s~2.5mm 2 / s range; a cylinder body contained in the closed container and forming a compression chamber; and a piston inserted in the compression chamber in a reciprocating manner, when its operating frequency is greater than 16r / s and less than 35r / s, the average speed of the reciprocating motion of the piston exceeds 0.31m / s.

[0024] In addition, the refrigeration device of the present invention only needs to include a refrigerant circuit, which includes the sealed refrigerant compressor, radiator, pressure reducing device and heat absorber of the above structure, and connects them into a ring structure through piping.

[0025] 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.

[0026] Effects of the Invention

[0027] In the present invention, the above-mentioned structure can provide a sealed refrigerant compressor that uses a refrigeration oil with a lower viscosity to achieve a better coefficient of performance (COP), an operating method thereof, and a refrigeration / refrigeration device using the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic cross-sectional view showing an example of the structure of a sealed refrigerant compressor in an embodiment of the present invention.

[0029] Figure 2 It is schematically enlarged Figure 1 A side view showing the structure of a piston and a cylinder in a compression member of a hermetic refrigerant compressor shown.

[0030] Figure 3A Yes means Figure 1 Schematic side view of an example of the structure of a piston of a sealed refrigerant compressor shown in FIG. Figure 3B This is a schematic side view showing an example of the structure of a conventional piston.

[0031] Figure 4A It means in Figure 1Schematic diagram of an example of a structure in which the sliding surface of a crankshaft of a sealed refrigerant compressor shown in FIG. Figure 4B , Figure 4C It means in Figure 3A The crankshaft shown is a schematic diagram of an example of a structure in which the sliding surface is divided into a plurality of surfaces.

[0032] Figure 5 It is schematically indicated Figure 1 FIG. 1 is a partial cross-sectional view showing an example of the distance P and the distance Q in the hermetic refrigerant compressor and the load (main shaft load) applied to the main shaft sliding portion.

[0033] Figure 6 It is schematically indicated Figure 1 FIG. 1 is a partial cross-sectional view of an example of the main structure of a thrust bearing in a hermetic refrigerant compressor shown in FIG.

[0034] Figure 7 Yes means including Figure 1 Schematic diagram of an example of the structure of a refrigeration and freezing device using a sealed refrigerant compressor shown.

[0035] Figure 8 This is a reference example of the present invention, and is a graph showing the relationship (characteristic) between the leakage amount of refrigerant gas and the kinematic viscosity of refrigeration oil when the operating frequency is 17 r / s in a conventional refrigerant compressor.

[0036] Fig. 9 This is a graph showing the relationship (characteristics) between the coefficient of performance (COP) and the kinematic viscosity of the refrigeration oil when the operating frequency is 27 r / s in the embodiment of the present invention and the conventional example.

[0037] Fig.10 This is a graph showing the relationship (characteristics) between the coefficient of performance (COP) and the kinematic viscosity of the refrigeration oil when the operating frequency is 17 r / s in the embodiment of the present invention and the conventional example. DETAILED DESCRIPTION

[0038] (Insights, etc. that form the basis of this disclosure)

[0039] In a sealed refrigerant compressor, a compression chamber is formed in a cylinder included in a cylinder body, and a piston is inserted into the compression chamber in a reciprocating manner. The refrigeration oil exists as an oil film between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder (the inner peripheral surface of the compression chamber), and lubricates the reciprocating motion (i.e., sliding) of the piston. For the sake of convenience, when the area between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder is referred to as "between the piston and the cylinder", if the kinematic viscosity of the refrigeration oil decreases, the oil film formed between the piston and the cylinder becomes thinner. Since the oil film becomes thinner, the sliding loss accompanying the reciprocating motion (sliding) of the piston can be reduced, but the possibility of refrigerant gas leakage from between the piston and the cylinder is also conceivable.

[0040] As described in the embodiments described below, the inventors experimentally verified and evaluated the amount of refrigerant gas leakage from the piston-cylinder space using refrigeration oils with different kinematic viscosities at 40°C in a sealed refrigerant compressor having a conventional structure under a low-speed operating frequency such as 17 r / s (rps). The results showed that when the kinematic viscosity of the refrigeration oil at 40°C was 2.5 mm / s, the leakage of the refrigerant gas from the piston-cylinder space was 2.5 mm / s. 2 / s or less, the leakage amount of the refrigerant gas increases.

[0041] Based on this verification evaluation, there is a tendency that the smaller the kinematic viscosity of the refrigeration oil used is, the greater the leakage of the refrigerant gas. However, even if the viscosity of the refrigeration oil is reduced, as long as it reaches 2.5 mm 2 / s ago, the sliding loss in the sealed refrigerant compressor can be effectively reduced, and its effect exceeds the influence caused by the increase in the leakage amount of the refrigerant gas, resulting in an improvement in the coefficient of performance (COP).

[0042] However, when the kinematic viscosity of the refrigeration oil at 40°C is 2.5 mm 2 / s or less, the leakage amount of the refrigerant gas becomes too large. Therefore, it is known that the refrigeration capacity of the refrigeration cycle including the sealed refrigerant compressor is reduced, and as a result, the coefficient of performance (COP) cannot be improved.

[0043] If the leakage of refrigerant gas from the piston-cylinder can be well suppressed while reducing the kinematic viscosity of the refrigeration oil, the coefficient of performance (COP) can be expected to be further improved in the sealed refrigerant compressor. However, it is difficult to achieve both low viscosity of the refrigeration oil and suppression of the leakage of the refrigerant gas.

[0044] Therefore, the present inventors have further conducted intensive studies and have found that the coefficient of performance (COP) can be improved by effectively suppressing the leakage of refrigerant gas from between the piston and the cylinder, thereby completing the present invention.

[0045] That is, the sealed refrigerant compressor of the present invention comprises: a sealed container; a refrigeration oil stored in the sealed container, and having a kinematic viscosity of 1.0 mm at 40°C. 2 / s~2.5mm 2 / s range; a cylinder body, which is housed in the closed container to form a compression chamber; and a piston, which is inserted inside the compression chamber in a reciprocating manner, and when the operating frequency is greater than 16r / s and less than 35r / s, the average speed of the reciprocating motion of the piston can be set to exceed 0.31m / s.

[0046] According to the above structure, when the operating frequency of the sealed refrigerant compressor is 16 r / s or more and 35 r / s or less, the lower limit of the average speed of the reciprocating motion of the piston (the average piston speed) is set. Thus, even if the operating speed of the sealed refrigerant compressor is relatively low, the average piston speed can be relatively high. Therefore, as a refrigeration oil, even if a lower viscosity (kinematic viscosity at 40°C is set to 1.0 mm 2 / s~2.5mm 2 / s) can also form a good oil film between the high-speed reciprocating piston and the compression chamber. As a result, it is possible to effectively suppress the leakage of refrigerant gas from the piston and the compression chamber. Therefore, when low-viscosity oil is used as refrigeration oil, the coefficient of performance (COP) of the sealed refrigerant compressor can be further improved.

[0047] In the sealed refrigerant compressor having the above structure, a ratio S / D of a stroke amount (S) of the reciprocating motion of the piston to a diameter (D) of the piston may be within a range of 0.78 to 1.00.

[0048] According to the above structure, in addition to making the piston average speed relatively high, the ratio S / D is set within the above range. By setting the ratio S / D, as described later, the stroke amount (S) can be relatively large or the piston diameter (D) can be relatively small.

[0049] Thus, the leakage of the refrigerant gas can be well suppressed, and the input power for reciprocating the piston can be reduced. Therefore, when low-viscosity oil is used as refrigeration oil, the coefficient of performance (COP) of the sealed refrigerant compressor can be further improved.

[0050] In addition, in the sealed refrigerant compressor of the above structure, it can also be constructed that, with respect to the above-mentioned piston, when the length of the area sealed in the above-mentioned compression chamber by the reciprocating motion of the above-mentioned piston is set as the sealing length (L2), the ratio L1 / D of the above-mentioned piston total length (L1) to the above-mentioned piston diameter (D) is in the range of 0.8 to 1.0, and the ratio L2 / L1 of the above-mentioned sealing length (L2) to the above-mentioned piston total length (L1) is in the range of 0.9 to 1.0.

[0051] According to the above configuration, in addition to increasing the average piston speed relatively, the ratio L1 / D and the ratio L2 / L1 are set within a predetermined range. By setting these ratios, as described later, the sealing length L2 can be relatively increased without excessively increasing the piston total length L1.

[0052] Thus, the increase of sliding loss between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder can be suppressed and the viscosity of the oil film can be increased, and the leakage of the refrigerant gas can be further suppressed. Therefore, the coefficient of performance (COP) of the sealed refrigerant compressor can be further improved.

[0053] Another hermetic refrigerant compressor of the present invention comprises: a hermetic container; a refrigeration oil stored in the hermetic container, the kinematic viscosity of which is between 1.0 mm and 2.0 mm at 40°C; 2 / s~2.5mm 2 / s; a cylinder body housed in the closed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, wherein the ratio S / D of the stroke (S) of the reciprocating motion of the piston to the diameter (D) of the piston is in the range of 0.78 to 1.00.

[0054] According to the above structure, as a refrigeration oil, the kinematic viscosity at 40°C is 1.0 mm 2 / s~2.5mm 2 When using a low viscosity oil in the range of 1 / 20 / s, the above ratio S / D is set within a specified range. As a result, the stroke amount (S) can be relatively increased, and thus the average piston speed can be relatively increased. Therefore, the leakage of refrigerant gas can be well suppressed.

[0055] In addition, when the low-viscosity oil is used as the refrigeration oil, the piston diameter (D) can be relatively reduced by setting the ratio S / D within a predetermined range, thereby reducing the total area of ​​the gap between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder, thereby effectively suppressing the leakage of the refrigerant gas.

[0056] Furthermore, when the piston diameter (D) becomes relatively small, the compression load of the refrigerant gas on the piston can be reduced, thereby reducing the input power for reciprocating the piston.

[0057] Therefore, by setting the ratio S / D within a predetermined range, when low-viscosity oil is used as refrigeration oil, the coefficient of performance (COP) of the hermetic refrigerant compressor can be further improved.

[0058] In the sealed refrigerant compressor of the above structure, it can also be constructed that, with respect to the above-mentioned piston, when the length of the area sealed in the above-mentioned compression chamber by the reciprocating motion of the above-mentioned piston is set as the sealing length (L2), the ratio L2 / L1 of the above-mentioned sealing length (L2) to the above-mentioned piston total length (L1) is in the range of 0.9 to 1.0.

[0059] According to the above structure, in addition to setting the ratio S / D of the piston stroke (S) to the piston diameter (D) within a specified range, the above ratio L1 / D and the ratio L2 / L1 are also set within a specified range. By setting these ratios, as described later, the sealing length L2 can be relatively increased without excessively increasing the total piston length L1.

[0060] Thus, the increase of sliding loss between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder can be suppressed and the viscosity of the oil film can be increased, and the leakage of the refrigerant gas can be further suppressed. Therefore, the coefficient of performance (COP) of the sealed refrigerant compressor can be further improved.

[0061] Another hermetic refrigerant compressor of the present invention comprises: a hermetic container; a refrigeration oil stored in the hermetic container, the kinematic viscosity of which is between 1.0 mm and 2.0 mm at 40°C; 2 / s~2.5mm 2 / s; a cylinder body housed in the closed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, when the ratio L1 / D of the total length of the piston (L1) to the diameter of the piston (D) is in the range of 0.8 to 1.0, and when the length of the area sealed in the compression chamber by the reciprocating motion of the piston is set as a sealing length (L2), the ratio L2 / L1 of the sealing length (L2) to the total length of the piston (L1) is in the range of 0.9 to 1.0.

[0062] According to the above structure, as a refrigeration oil, the kinematic viscosity at 40°C is 1.0 mm 2 / s~2.5mm 2 When using a low viscosity oil within the range of 1 / 200 rpm to 1 / 400 rpm, the above ratio L1 / D and ratio L2 / L1 are set within the specified range. As a result, the increase in sliding loss can be suppressed, and the sealing length (L2) can be relatively increased without excessively increasing the total length of the piston (L1). Therefore, between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder, the increase in sliding loss can be suppressed and the viscosity of the oil film can be increased.

[0063] In addition, the area sealed by the oil film of the refrigeration oil between the piston and the cylinder can be relatively increased, thereby further suppressing the leakage of the refrigerant gas.

[0064] Furthermore, when the seal length (L2) is increased, the posture of the piston reciprocating in the compression chamber can be stabilized. As a result, the increase in sliding loss can be further suppressed.

[0065] Therefore, by setting the ratio L1 / D and the ratio L2 / L1 within a predetermined range, when low-viscosity oil is used as refrigeration oil, the coefficient of performance (COP) of the sealed refrigerant compressor can be further improved.

[0066] In a sealed refrigerant compressor of any of the above-mentioned structures, it can also be constructed that the above-mentioned compression component includes: a crankshaft as a shaft portion, having a main shaft and an eccentric shaft; and an eccentric bearing as a bearing portion for axially supporting the above-mentioned shaft portion, which axially supports the main shaft and the above-mentioned eccentric bearing, wherein the sliding surface of the above-mentioned main shaft and the above-mentioned main bearing is divided into a plurality of surfaces, and when the total axial lengths of the plurality of sliding surfaces are taken as the total sliding length Tt, the ratio Tt / K of the total sliding length Tt to the outer diameter K of the above-mentioned main shaft is less than 1.26.

[0067] According to the above structure, by applying the setting structure of the ratio Tt / K and the structure using a sulfur-based sliding modifier, even when a low-viscosity lubricating oil is used to reduce the sliding area, the main shaft sliding part composed of the main shaft-main bearing can be well lubricated, and the wear of the main shaft sliding part can be well suppressed. As a result, the reliability of the refrigerant compressor can be further improved. In addition, even when the operating frequency is at a low speed of more than 16r / s and less than 35r / s, even if the supply of refrigeration oil is reduced, good wear resistance can be achieved. Therefore, the increase in sliding loss of the main shaft sliding part can be suppressed, so a good performance coefficient (COP) can be achieved.

[0068] In a sealed refrigerant compressor of any of the above structures, it can also be constructed that the above compression component includes: a crankshaft as an axis portion, having a main shaft and an eccentric shaft; and an eccentric bearing as a bearing portion for axially supporting the above axis portion, which axially supports the main shaft and the above eccentric bearing, wherein the sliding surface of the above main shaft with the above main bearing is a single surface or is divided into multiple surfaces, and when the above sliding surface is a single surface, when the axial length of the sliding surface is set to a single sliding length T, or when the above sliding surface is divided into multiple surfaces, when the axial length of the sliding surface with the smallest axial length is set to a single sliding length T, the ratio T / K of the single sliding length T to the outer diameter K of the above main shaft is less than 0.51, and in the above refrigeration oil, sulfur or a compound containing sulfur is contained as a sliding property modifier.

[0069] According to the above structure, by applying the setting structure of the ratio T / K and the structure using a sulfur-based sliding modifier, even when a low-viscosity lubricating oil is used to reduce the sliding area, the main shaft sliding part composed of the main shaft-main bearing can be well lubricated, and the wear of the main shaft sliding part can be well suppressed. As a result, the reliability of the refrigerant compressor can be further improved. In addition, even when the operating frequency is at a low speed of more than 16r / s and less than 35r / s, even if the supply of refrigeration oil is reduced, good wear resistance can be achieved. Therefore, the increase in sliding loss of the main shaft sliding part can be suppressed, so a good performance coefficient (COP) can be achieved.

[0070] In the sealed refrigerant compressor of any of the above-mentioned structures, it can also be constructed that the above-mentioned compression component also includes: a crankshaft having a main shaft and an eccentric shaft; a main bearing for axially supporting the above-mentioned main shaft; and a thrust bearing arranged on the thrust surface of the above-mentioned main bearing, in the sliding surface of the above-mentioned main bearing, the end on the above-mentioned compression chamber side is set as the first end, and the end on the opposite side is set as the second end, the distance between the axis center of the above-mentioned compression chamber and the second end of the sliding surface of the above-mentioned main bearing is set as P, and the distance between the axis center of the above-mentioned compression chamber and the first end of the sliding surface of the above-mentioned main bearing is set as Q, when the above-mentioned distance P is in the range of 38mm to 51mm, the above-mentioned distance Q is less than 16mm.

[0071] According to the above structure, even if only low-viscosity oil is used as refrigeration oil, the main shaft load can be reduced, but by setting the distance Q of the refrigerant compressor to less than 16 mm, the main shaft load can be further reduced. Therefore, high efficiency and good reliability of the refrigerant compressor can be achieved not only in the sliding part between the piston and the cylinder, but also in the main shaft sliding part. As a result, the coefficient of performance (COP) of the refrigerant compressor can be further improved.

[0072] In addition, the present invention also includes a method for operating a sealed refrigerant compressor. That is, the method for operating a sealed refrigerant compressor of the present invention is that the sealed refrigerant compressor comprises: a sealed container; a refrigeration oil stored in the sealed container, and having a kinematic viscosity of 1.0 mm at 40°C. 2 / s~2.5mm 2 / s range; a cylinder body housed in the closed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, in a closed refrigerant compressor, when its operating frequency is greater than 16r / s and less than 35r / s, the average speed of the reciprocating motion of the piston exceeds 0.31m / s.

[0073] In addition, the present invention also includes a refrigeration / refrigeration device using a sealed refrigerant compressor of the above structure, or a sealed refrigerant compressor that performs the operation method of the above structure. That is, the refrigeration / refrigeration device of the present invention only needs to include a sealed refrigerant compressor of the above structure (or a sealed refrigerant compressor that performs the operation method of the above structure), a radiator, a decompression device, and a heat absorber, and include a structure that connects them into a ring refrigerant circuit through piping.

[0074] Hereinafter, representative embodiments of the present invention will be specifically described with reference to the accompanying drawings. However, a detailed description of a part of the following embodiments may be omitted. For example, a detailed description of a known matter or a repeated description of a substantially identical structure may be omitted. This is to avoid the following description being too lengthy and to make it easy for those skilled in the art to understand.

[0075] In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present invention, and are not intended to limit the subject matter described in the patent claims.

[0076] (Implementation Method 1)

[0077] [Structure of a sealed refrigerant compressor]

[0078] First, refer to Figure 1 A typical structural example of the hermetic refrigerant compressor of the present invention will be described in detail. Figure 1 This is a schematic cross-sectional view showing an example of the structure of a sealed refrigerant compressor 100 (hereinafter, sometimes simply referred to as a refrigerant compressor 100 ) according to Embodiment 1 of the present invention.

[0079] like Figure 1As shown, the refrigerant compressor 100 is filled with, for example, R600a as a refrigerant gas 181 in a sealed container 102, and mineral oil is stored at the bottom as refrigeration oil 180. In addition, a compressor body 108 is accommodated in the sealed container 102, and the compressor body 108 is elastically supported by a suspension spring 190. In addition, the compressor body 108 includes an electric component 104 and a compression component 106.

[0080] The electric component 104 is composed of at least a stator 150 and a rotor 152. The compression component 106 is a reciprocating structure driven by the electric component 104, and includes a crankshaft 120, a cylinder 130, a piston 140, a connecting mechanism 142, etc. The crankshaft 120 is composed of at least a main shaft 124 with a rotor 152 heat-pressed and an eccentric shaft 122 formed eccentrically with respect to the main shaft 124. In the present embodiment, the crankshaft 120 is composed of, for example, an iron material.

[0081] In addition, a flange portion 128 is provided between the main shaft 124 and the eccentric shaft 122. Figure 1 As shown by the dashed line, the rotation axis of the crankshaft 120 corresponds to the axis of the main shaft 124. The main shaft 124 and the eccentric shaft 122 are fixed via the flange 128 in a manner that the axes are offset from each other. Therefore, the axis of the eccentric shaft 122 is eccentric with respect to the axis of the main shaft 124 (the rotation axis of the crankshaft 120).

[0082] The eccentric shaft 122 in the crankshaft 120 is located on the upper side of the refrigerant compressor 100, and the main shaft 124 is located on the lower side of the refrigerant compressor 100. Therefore, when describing the position of the crankshaft 120, the upper and lower positional relationship (direction) is also 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 is connected to the main shaft 124.

[0083] The upper end of the main shaft 124 is connected to the eccentric shaft 122, and the lower end of the main shaft 124 faces the inner lower surface of the closed container 102, and the lower end of the main shaft 124 is immersed in the refrigeration oil 180. In addition, the crankshaft 120 is provided with an oil supply mechanism 125, and the oil supply mechanism 125 supplies the refrigeration oil 180 from the lower end of the main shaft 124 immersed in the refrigeration oil 180 to the upper end of the eccentric shaft 122. As described later, the refrigeration oil 180 lubricates the various sliding parts of the refrigerant compressor 100 and plays a sealing role between the compression chamber 133 and the piston 140.

[0084] The outer peripheral surface of the main shaft 124 of the crankshaft 120 includes sliding surfaces 126a, 126b and a non-sliding outer peripheral surface 127. For the sake of convenience, the sliding surface 126a on the upper side of the main shaft 124 is referred to as the first sliding surface 126a, and the sliding surface 126b on the lower side of the main shaft 124 is referred to as the second sliding surface 126b. The non-sliding outer peripheral surface 127 is located between the first sliding surface 126a and the second sliding surface 126b.

[0085] In the present invention, a "sliding surface" refers to an outer peripheral surface or an inner peripheral surface of a plurality of sliding parts constituting a sliding portion, and is a surface that can slidably contact with the inner peripheral surface or outer peripheral surface of the other party. A "non-sliding outer peripheral surface (non-sliding surface)" is different from a sliding surface and is a surface that does not contact with the inner peripheral surface or outer peripheral surface of the other party. In the present embodiment, the non-sliding outer peripheral surface 127 is a structure in which the outer diameter of the main shaft 124 is smaller than the sliding surfaces 126a and 126b (the outer diameter is made thinner, recessed from the sliding surfaces 126a and 126b, or formed hollow).

[0086] The cylinder block 130 includes a cylinder 132 and a main bearing 134. The cylinder 132 forms a compression chamber 133 inside. The main bearing 134 rotatably supports the main shaft 124. In the present embodiment, the cylinder 132 and the main bearing 134 are integrally formed into one cylinder block 130 using, for example, cast iron.

[0087] In this embodiment, if Figure 1 As shown in FIG. 1 , when the extension direction (up-down direction) of the crankshaft 120 is set as the “longitudinal direction”, the cylinder block 130 has a main body extending in the “lateral direction” (direction orthogonal to the longitudinal direction) inside the refrigerant compressor 100. The main bearing 134 is formed in a tubular (cylindrical) shape extending in the “longitudinal direction” (up-down direction) relative to the main body of the cylinder block 130. The inner peripheral surface of the main bearing 134 is in contact with the outer peripheral surface of the main shaft 124, that is, the sliding surfaces 126a and 126b in a slidable manner. Therefore, the inner peripheral surface of the main bearing 134 is a sliding surface.

[0088] In addition, the non-sliding outer peripheral surface 127 of the main shaft 124 is located between the upper end and the lower end of the main bearing 134. Therefore, when the main shaft 124 is axially supported by the main bearing 134, the upper end of the main bearing 134 contacts the first sliding surface 126a of the main shaft 124, and the lower end of the main bearing 134 contacts the second sliding surface 126b. At this time, the non-sliding outer peripheral surface 127 having an outer diameter smaller than the sliding surfaces 126a and 126b does not contact the inner peripheral surface (sliding surface) of the main bearing 134, and does not protrude from the upper end and the lower end of the main bearing 134.

[0089] In this embodiment, main bearing 134 includes thrust surface 136 and tubular extension 137. Thrust surface 136 of main bearing 134 is a plane portion extending in a direction (vertical direction, horizontal direction) orthogonal to the axis, that is, the extending direction (up and down direction) of main shaft 124.

[0090] The tubular extension 137 of the main bearing 134 is a tubular (cylindrical) shape that is further extended upward than the thrust surface 136. In other words, it is a portion that is extended upward from the tubular main body of the main bearing 134. Therefore, the tubular extension 137 and the main body of the main bearing 134 have an inner peripheral surface (sliding surface) that faces the outer peripheral surface (sliding surface) of the main shaft 124. The thrust surface 136 of the main bearing 134 is provided with a thrust ball bearing 210.

[0091] The cylinder 132 is provided in the main body of the cylinder body 130, and the interior of the cylinder 132 becomes a compression chamber 133. The compression chamber 133 is a cylindrical (columnar) hole extending in the "lateral" direction inside the refrigerant compressor 100. The piston 140 is inserted in a manner that allows reciprocation relative to the compression chamber 133. Therefore, the compression chamber 133 is closed by the insertion of the piston 140. In addition, the direction of the reciprocating motion of the piston 140 is the "lateral" direction.

[0092] The connection mechanism 142 is made of, for example, aluminum casting, axially supports the eccentric shaft 122, and is connected to the piston 140. Therefore, the eccentric shaft 122 and the piston 140 are connected via the connection mechanism 142.

[0093] The electric component 104 includes a rotor 152 and a stator 150 coaxially arranged 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 so as to maintain a substantially constant gap with the rotor 152, and is fixed to the leg portion of the cylinder block 130. In addition, the rotor 152 is fixed to the main shaft 124 of the crankshaft 120.

[0094] Therefore, in the refrigerant compressor 100, when the rotor 152 is rotated by the electric component 104, the crankshaft 120 is rotated. In the crankshaft 120, as described above, the axis of the eccentric shaft 122 is offset relative to the axis of the main shaft 124, and the eccentric shaft 122 is connected to the piston 140 through the connection mechanism 142. The piston 140 is inserted into the compression chamber 133 in the cylinder 132 in a reciprocating manner. Therefore, when the crankshaft 120 rotates, the piston 140 reciprocates in the compression chamber 133 by the rotation of the eccentric shaft 122.

[0095] In addition, as the crankshaft 120 rotates, as described above, the refrigeration oil 180 is supplied to each sliding part from the oil supply mechanism 125. Thus, each sliding part is lubricated by the refrigeration oil 180.

[0096] In the present embodiment, the sliding parts include the main shaft 124 and main bearing 134 of the crankshaft 120, the piston 140 and the compression chamber 133 (cylinder 132), the connecting part between the connecting mechanism 142 and the piston 140, and the connecting part between the eccentric shaft 122 of the crankshaft 120 and the connecting mechanism 142. In addition, each component constituting these sliding parts is a sliding component.

[0097] In addition, for the sake of convenience, the sliding part composed of the piston 140 and the compression chamber 133 (cylinder 132) among these sliding parts is referred to as a "cylinder sliding part". In addition, for the sake of convenience, the sliding part composed of the main shaft 124 of the crankshaft 120 and the main bearing 134 is referred to as a "main shaft sliding part".

[0098] In addition, the specific structure of the refrigerant compressor 100 of the present invention is not limited to the above Figure 1 The refrigerant compressor 100 of the present invention includes an electric component 104 and a compression component 106. The compression component 106 may be any structure including a cylinder 130 having a compression chamber 133 and a piston 140 inserted into the compression chamber 133 in a reciprocating manner.

[0099] For example, in Figure 1 In the refrigerant compressor 100 shown, the electric component 104 is located at the lower side and the compression component 106 is located at the upper side in the closed container 102. However, the electric component 104 may be located at the upper side and the compression component 106 may be located at the lower side.

[0100] Or, in Figure 1 In the refrigerant compressor 100 shown, the electric component 104 is an inner rotor type, and the rotor 152 is configured to be rotatable coaxially with the stator 150 on the inner periphery of the stator 150. However, the structure of the electric component 104 is not limited to this, and it may be an outer rotor type, that is, the rotor 152 may be configured to be rotatable coaxially with the stator 150 on the outer periphery of the stator 150.

[0101] Or, in Figure 1 In the refrigerant compressor 100 shown, the main shaft 124 of the crankshaft 120 has a first sliding surface 126a, a non-sliding outer peripheral surface 127, and a second sliding surface 126b. However, the structure of the main shaft 124 is not limited thereto, and as shown in Embodiment 2 described later, the sliding surface 126 of the main shaft 124 may constitute the entire outer peripheral surface of the main shaft 124, or may include more than three sliding surfaces 126.

[0102] The specific composition of the refrigerating machine oil 180 used in the present invention is not particularly limited. In the present invention, as the refrigerating machine oil 180, a refrigerating machine oil having a kinematic viscosity of 1.0 mm at 40° C. is used. 2 / s~2.5mm 2 / s range (1.0mm 2 / s or more and 2.5mm 2 The specific structure of the low-viscosity oil is not particularly limited. In the first embodiment, for example, a low-viscosity mineral oil is used. However, as described in the fourth embodiment described later, other oily substances may be used instead of the mineral oil, or other oily substances may be used together with the mineral oil, or various additives may be added.

[0103] In addition, the refrigeration oil 180 (low viscosity oil) in the present invention has a kinematic viscosity of more than 2.5 mm at 40°C. 2 / s, the viscous resistance becomes too large from the viewpoint of achieving a good coefficient of performance (COP). If the viscous resistance becomes large, the input power to the refrigerant compressor 100 becomes large, so that a better coefficient of performance (COP) cannot be achieved.

[0104] On the other hand, when the kinematic viscosity of the refrigeration oil 180 at 40°C is less than 1.0 mm 2 / s, the oil film formed on each sliding part inside the refrigerant compressor 100 becomes too thin. If the oil film in the sliding part becomes thinner, the possibility of fracture becomes higher, and good lubrication effect cannot be obtained in the sliding part. As a result, the metal contact between the sliding surfaces in the sliding part increases, and the reliability of the sliding part may be reduced.

[0105] Here, the kinematic viscosity of the refrigerating machine oil 180 at 40°C of the present invention may be within the above range, and its upper limit or lower limit may be appropriately changed within the above range according to various conditions. For example, the upper limit of the kinematic viscosity of the refrigerating machine oil 180 at 40°C may be 2.4 mm 2 / s. In addition, the lower limit of the kinematic viscosity of the refrigeration oil at 180°C at 40°C may be 1.5 mm 2 / s.

[0106] In addition, these upper and lower limits may be values ​​that include the value (below or above) or values ​​that do not include the value (less than or more than). For example, the upper limit may be less than 2.5 mm. 2 / s, can also be 2.4mm 2 / s or less, and can also be less than 2.4mm 2 / s. The lower limit value is the same. Although it depends on various conditions, by setting the kinematic viscosity of the refrigerating machine oil 180 at 40°C to 2.4 mm 2 / s or less than 2.4mm 2 / s, or 1.5mm 2 / s or more or greater than 1.5mm 2 / s or more, from the viewpoint of achieving a better coefficient of performance (COP), a more appropriate viscous resistance or a more appropriate oil film thickness can be easily achieved.

[0107] [Operation method and piston structure of refrigerant compressor]

[0108] Next, refer to Figure 1 The refrigerant compressor 100 shown in the figure illustrates the operation method of the hermetic refrigerant compressor of the present invention and the piston structure of the hermetic refrigerant compressor. In addition, the "piston structure" mentioned here includes not only the specific structure of the piston 140 itself, but also the conditions set when the piston 140 reciprocates in the compression chamber 133, etc.

[0109] In the refrigerant compressor 100, first, by supplying power from the industrial frequency power supply to the electric component 104, the rotor 152 of the electric component 104 rotates. By the rotation of the rotor 152, as described above, the crankshaft 120 rotates, so the eccentric motion of the eccentric shaft 122 relative to the main shaft 124 is transmitted to the piston 140 via the connecting mechanism 142. As a result, the eccentric motion of the eccentric shaft 122 is converted into the reciprocating motion of the piston 140, and the piston 140 is driven in a manner of reciprocating motion inside the cylinder 132, that is, in the compression chamber 133. The refrigerant gas 181 introduced into the closed container 102 is sucked into the compression chamber 133 by the reciprocating motion of the piston 140 and compressed.

[0110] Here, in the present invention, it is preferred that the refrigerant compressor 100 is frequency-variable driven at multiple operating frequencies. That is, the refrigerant compressor 100 of the present invention can also be used as a controller for controlling the operation of the refrigerant compressor 100, and at least includes an inverter circuit for controlling the operating frequency. The specific structure of the inverter circuit is not particularly limited, as long as the electric component 104 can be rotationally driven at multiple operating speeds. The inverter circuit can be chip-based, or it can be a microprocessor that operates by executing a program for rotational drive based on multiple operating speeds.

[0111] In the present invention, the operating frequency of the refrigerant compressor 100 is not particularly limited. Generally, if the operating frequency of the refrigerant compressor 100 is reduced, its power consumption can be suppressed. However, in a refrigeration cycle (refrigeration / refrigeration device) including the refrigerant compressor 100, the operating frequency can also be increased according to the peak value of its refrigeration capacity. Therefore, the operating frequency of the refrigerant compressor 100 is not always within a low range.

[0112] Here, in the present invention, as the refrigeration oil 180 stored in the closed container 102 of the refrigerant compressor 100, a refrigeration oil having a kinematic viscosity of 1.0 mm / s at 40° C. is used. 2 / s~2.5mm 2 / s range of low viscosity oil (low viscosity lubricating oil).

[0113] When low-viscosity oil is used as the refrigeration oil 180, the sliding loss can be reduced, but on the other hand, there is a tendency for the lubrication effect of the sliding part to be reduced. Therefore, when the refrigeration oil 180 is low-viscosity oil, as a method to avoid or suppress the reduction of the lubrication effect, for example, surface treatment is usually selected for the sliding surface constituting the sliding part.

[0114] Furthermore, as described above, according to the research of the present inventors, if the kinematic viscosity of the refrigerating machine oil 180 at 40°C is 2.5 mm 2 / s or less, the leakage of the refrigerant gas 181 from the piston 140-cylinder 132 (between the outer peripheral surface of the piston 140 and the inner peripheral surface of the cylinder 132 (the inner peripheral surface of the compression chamber 133)) becomes too large (also refer to the embodiments described later). As a method for suppressing the leakage of the refrigerant gas 181, for example, a corresponding method of reducing the gap between the surface of the piston 140 and the inner surface of the compression chamber 133 is generally selected.

[0115] On the other hand, in the present invention, the refrigerating machine oil 180 stored in the sealed container 102 is used with a kinematic viscosity of 1.0 mm at 40°C. 2 / s~2.5mm 2 When the operating frequency is controlled to be greater than 16 r / s and less than 35 r / s using an inverter circuit (or controller), the refrigerant compressor 100 is operated in such a way that the average speed of the reciprocating motion of the piston 140 (average piston speed) exceeds 0.31 m / s.

[0116] By using such an operation method, even if the refrigerating machine oil 180 having a kinematic viscosity of 2.5 mm at 40° C. is used, 2 / s or less, in the "cylinder sliding part", i.e., the sliding part composed of the piston 140 and the compression chamber 133 in the cylinder 132, the oil film of the refrigeration oil 180 can also exert good viscous force (viscous resistance) between the piston 140 and the cylinder 132. As a result, good sliding performance can be achieved in the cylinder sliding part, and leakage of the refrigerant gas 181 can also be effectively suppressed.

[0117] Therefore, even when the refrigerant compressor 100 is operated within a low operating frequency range, that is, when the operating frequency is controlled within the range of 16r / s to 35r / s, the increase in power consumption of the refrigerant compressor 100 can be suppressed or avoided, and a good coefficient of performance (COP) can be achieved in the refrigerant compressor 100.

[0118] On the other hand, in the cylinder sliding portion, when the oil film of the refrigeration oil 180 cannot exert good viscosity, it is difficult to maintain a good oil film between the piston 140 and the cylinder 132 relative to the pressure of the refrigerant gas 181 in the compression chamber 133. As a result, the oil film is easily broken between the piston 140 and the cylinder 132, resulting in a significant amount of refrigerant gas 181 leakage.

[0119] Reference Figure 2 The viscosity of the oil film of the refrigerating machine oil 180 in the cylinder sliding portion will be described in detail. Figure 2 Yes Figure 1 This is a schematic side view (schematic partial cross-sectional view) showing an enlarged view of a main part of the structure of a cylinder sliding portion included in the refrigerant compressor 100.

[0120] exist Figure 2 , a portion of the cylinder 132 of the cylinder body 130, a portion of the compression chamber 133 formed in the cylinder 132, and a portion of the piston 140 slidably inserted in the compression chamber 133 are schematically illustrated. The compression chamber 133 is filled with refrigerant gas 181, and an oil film formed of refrigeration oil 180 is formed between the outer peripheral surface of the piston 140 and the inner peripheral surface of the cylinder 132 (the inner peripheral surface of the compression chamber 133).

[0121] When the viscous force (F1) of the oil film of the refrigeration oil 180 inserted between the piston 140 and the cylinder 132 is applied, the viscous force (F1) can be expressed by the following formula (1) through the viscosity (η) of the refrigeration oil 180, the sealing length (L2) of the piston 140, the gap (σ) between the piston 140 and the cylinder 132, and the average speed of the piston (V).

[0122] F1=(η×L2×V) / σ···(1)

[0123] In addition, the sealing length (L2) is the length of the area where the piston 140 seals the compression chamber 133 through its reciprocating motion. Figure 2 The hollow arrows in the figure schematically indicate the force from the outside to the inside of the compression chamber 133. In addition, the gap (σ) between the piston 140 and the cylinder 132 is Figure 2 As schematically shown in FIG. 1 , ideally, the gap (σ) is filled with the oil film of the refrigeration oil 180 without any break.

[0124] If the viscosity (F1) of the oil film decreases, it becomes difficult for the refrigeration oil 180 to maintain the state of the oil film between the piston 140 and the cylinder 132 relative to the pressure of the refrigerant gas 181 filling the compression chamber 133. As a result, the oil film between the piston 140 and the cylinder 132 is easily broken, and as a result, a significant amount of the refrigerant gas 181 is easily leaked.

[0125] Therefore, in order to increase the viscosity (F1) of the oil film, the average piston speed (V) may be increased (speeded up), the sealing length (L2) of the piston 140 may be increased, and the gap (σ) between the piston 140 and the cylinder 132 may be reduced.

[0126] In the present invention, when the refrigeration oil 180 is a low-viscosity oil, the average piston speed (V) is set large in order to exert a good viscous force of the oil film between the piston 140 and the cylinder 132. In the cylinder sliding part, since the piston 140 reciprocates, the actual movement speed of the piston 140 in the compression chamber 133 is not constant. Therefore, in the present invention, the average piston speed is used. The average piston speed (V) can be defined by the product of the stroke amount (S) of the piston 140 and the operating frequency (Fr) (V = S × Fr).

[0127] In the present invention, the operating frequency (operating speed) of the refrigerant compressor 100 is not particularly limited. Representatively, 13 r / s (rps) can be cited as the lower limit of the operating frequency, and the lower limit can also be 16 r / s. On the other hand, 80 r / s can be cited as the upper limit of the operating frequency, and the upper limit can be 75 r / s.

[0128] Therefore, as an example of a representative range of operating frequency, the range of 13 to 80 r / s can be cited, or the range of 16 to 75 r / s can be cited. Of course, it can be in the range of 16 to 80 r / s, or in the range of 13 to 75 r / s. In addition, the input power to the refrigerant compressor 100 becomes larger, but the upper limit of the operating frequency can also exceed 80 r / s.

[0129] In addition, from the perspective of reducing the input power to the refrigerant compressor 100, the operating frequency can also be made smaller than 13r / s. However, when the operating frequency is made too small, the coefficient of performance (COP) of the refrigerant compressor 100 and the wear of the cylinder sliding part may not be able to obtain sufficient reliability. Therefore, as a preferred lower limit of the operating frequency, 16r / s can be given as an example.

[0130] In the present invention, such an operating frequency range, particularly a range of 16 r / s to 35 r / s, is defined as a "low-speed operating frequency". In the refrigerant compressor 100 of the present invention, when in the low-speed operating frequency range, the average piston speed is increased to a speed exceeding 0.31 m / s. Therefore, the lower limit of the average piston speed in the present invention only needs to exceed 0.31 m / s.

[0131] When the average piston speed is below 0.31 m / s, the oil film of low-viscosity oil (refrigeration oil 180) cannot exert sufficient viscous force between the piston 140 and the cylinder 132. As a result, when the refrigerant compressor 100 is operated within the range of low speed operation frequency, the refrigerant gas 181 is easy to leak from between the piston 140 and the cylinder 132.

[0132] In addition, as described above, the lower limit of the average piston speed only needs to be more than 0.31 m / s, but it may be more than 0.32 m / s or more than 0.34 m / s depending on various conditions. If the lower limit of the average piston speed is more than 0.32 m / s, then although it also depends on various conditions, the oil film of the refrigeration oil 180 between the piston 140 and the cylinder 132 is likely to exert a better viscous force. As a result, the refrigerant gas 181 can be more effectively suppressed from leaking from between the piston 140 and the cylinder 132.

[0133] In the present invention, a structure can be adopted in which the ratio S / D of the stroke amount (S) of the reciprocating motion of the piston 140 to the piston diameter (D) is set within the range of 0.78 to 1.00 (0.78≤S / D≤1.00) based on the above-mentioned formula (1). The stroke amount (S) of the reciprocating motion of the piston 140 is determined by twice the eccentric radius of the eccentric shaft 122. This ratio S / D is equivalent to the condition set when the piston 140 reciprocates in the compression chamber 133, and therefore can be referred to as the above-mentioned piston structure.

[0134] By setting the ratio S / D of the stroke amount (S) to the piston diameter (D) within the above range, the stroke amount of the piston 140 can be relatively lengthened (increased), and thus the piston average speed (V) can be increased. When the piston average speed (V) changes, as described above, even in this way, the viscosity force (F1) of the oil film can be increased, and the oil film can be easily formed between the piston 140 and the cylinder 132. Thus, the leakage of the refrigerant gas 181 can be suppressed.

[0135] Furthermore, when the ratio S / D is within the above range, the stroke amount (S) becomes larger, which means that the piston diameter (D) becomes relatively smaller. By reducing the piston diameter (D), the total area of ​​the gap (σ) between the piston 140 and the cylinder 132 can be reduced. The reduction in the total area of ​​the gap means that the "opening area" itself, where the refrigerant gas 181 may leak out, becomes narrower. Therefore, it is possible to suppress the refrigerant gas 181 from leaking from the piston 140 and the cylinder 132.

[0136] Furthermore, when the piston diameter (D) becomes smaller, the compression load of the piston 140 on the refrigerant gas 181 can be reduced. That is, when the piston 140 reciprocates in the compression chamber 133, the load applied to the front end surface of the piston 140 from the refrigerant gas 181 in the compression chamber 133 becomes relatively smaller. As a result, the input power for reciprocating the piston 140 can be reduced. Therefore, the coefficient of performance (COP) of the refrigerant compressor 100 can be improved.

[0137] So far, in the field of refrigerant compressor 100, as disclosed in "Sealed Refrigerator" by Mutsuyoshi Kawahira, Japan Refrigeration Association, and published in July 1981, the ratio S / D of the stroke amount (S) to the piston diameter (D) is preferably in the range of 0.4 to 0.8. In contrast, in the present invention, the ratio S / D is set in the range of 0.78 to 1.00. Therefore, the ratio S / D in the present invention is set to be substantially larger than the existing range. In particular, in the present invention, the lower limit of the ratio S / D can be greater than 0.81 (0.81≤S / D), and can also be greater than 0.84 (0.84≤S / D).

[0138] If the ratio S / D is less than 0.78, a low-viscosity oil (kinematic viscosity at 40° C. is 1.0 mm 2 / s~2.5mm 2 When the ratio S / D is within the range of 0.81 / s, the stroke amount (S) of the piston 140 cannot be relatively increased, and the piston diameter (D) may not be relatively decreased. If the lower limit of the ratio S / D is greater than 0.81, the effect of making the stroke amount (S) relatively large and the piston diameter (D) relatively small can be more reliably achieved. If the lower limit of the ratio S / D is greater than 0.84, the above effect can be further reliably achieved.

[0139] On the other hand, when the ratio S / D exceeds 1.00, the stroke amount (S) of the piston 140 becomes relatively too large, and the sliding loss between the piston 140 and the cylinder 132 becomes relatively large. As a result, the effect of achieving a good coefficient of performance (COP) in the refrigerant compressor 100 cannot be obtained.

[0140] In addition, there is no particular limitation on the specific stroke amount (S) of the piston 140. In the present embodiment, for example, the lower limit of the stroke amount (S) can be 19.5 mm or more. The lower limit of the stroke amount (S) can also be 20 mm or more. On the other hand, the upper limit of the stroke amount (S) is not particularly limited either, but when the stroke amount (S) becomes too large, the sliding loss between the piston 140 and the cylinder 132 may become relatively large. From this point of view, the upper limit of the stroke amount (S) can be 30 mm or less.

[0141] In addition, regarding the gap (σ) between the piston 140 and the cylinder 132, the specific gap is not particularly limited, but in the present embodiment, for example, 3 μm can be given as the lower limit of the gap (σ), and 10 μm can be given as the upper limit of the gap (σ). When the gap (σ) exceeds 10 μm, especially when low-viscosity oil is used as the refrigeration oil 180, the viscous force (F1) becomes smaller (refer to the above-mentioned formula (1)).

[0142] On the other hand, if the clearance (σ) is smaller than 3 μm, particularly when low-viscosity oil is used as the refrigeration oil 180 , the reciprocating piston 140 may easily come into contact with the inner peripheral surface of the cylinder 132 (compression chamber 133 ).

[0143] In the present invention, based on the above-mentioned formula (1), a structure is adopted in which the ratio L1 / D of the total length of the piston (L1) to the piston diameter (D) in the piston 140 is in the range of 0.8 to 1.0 (0.8≤L1 / D≤1.0), and the ratio L2 / L1 of the sealing length (L2) to the total length of the piston (L1) is in the range of 0.9 to 1.0 (0.9≤L2 / L1≤1.0).

[0144] Among these ratios, the ratio L1 / D corresponds to the specific structure (condition) of the piston 140, and the ratio L2 / L1 corresponds to the condition set when the piston 140 reciprocates in the compression chamber 133. Therefore, these ratios can be referred to as the above-mentioned piston structure.

[0145] Regarding the case where the relationship between the piston diameter (D), the piston total length (L1) and the seal length (L2) is defined by the ratio L1 / D and the ratio L2 / L1 in the piston 140, refer to Figure 3A and Figure 3B Provide specific instructions. Figure 3A Yes means Figure 1 FIG. 1 is a schematic side view of a representative example of a piston 140 used in the refrigerant compressor 100 shown in FIG. Figure 3B This is a schematic side view showing a typical example of a conventional piston.

[0146] like Figure 3A As shown, regarding the piston 140 used in the refrigerant compressor 100 of the present embodiment, the piston total length (L1), i.e., the length in the direction of the reciprocating motion of the piston 140, is equal to the piston diameter (D), i.e., the diameter of the piston 140. In addition, in the piston 140, the piston total length (L1) is also equal to the sealing length (L2), i.e., the length of the region in the compression chamber 133 sealed by the reciprocating motion of the piston 140 described above.

[0147] In contrast, Figure 3BAs shown, in the conventional piston 240, the overall piston length (L1) is increased relative to the piston diameter (D), and the overall piston length (L1) is increased relative to the sealing length (L2).

[0148] According to the above formula (1), if the sealing length (L2) is increased, the viscosity (F1) of the oil film of the refrigeration oil 180 can be increased. In addition, if the sealing length (L2) is increased, it means that the area sealed by the oil film in the cylinder sliding part becomes larger. Therefore, if the sealing length (L2) is relatively large, the leakage of the refrigerant gas 181 can be well suppressed.

[0149] In order to ensure a sufficient sealing length (L2), the piston total length (L1) must also be sufficient. On the other hand, when the piston total length (L1) is too large, the sliding loss of the cylinder sliding part increases. In particular, when the refrigeration oil 180 is a low-viscosity oil (kinematic viscosity at 40°C is 2.5 mm 2 / s or less), it is difficult to form a good oil film on the cylinder sliding part compared with oil with higher viscosity.

[0150] Therefore, the reference for setting an appropriate piston total length (L1) was studied intensively, and it was found that, particularly when the refrigeration oil 180 is a low-viscosity oil, the piston diameter (D) can be used as a reference.

[0151] like Figure 3A When the ratio L1 / D is within the range of 0.8 to 1.0, the cylinder sliding portion is provided with an appropriate range of the piston total length (L1) corresponding to the low viscosity oil, as shown in the piston 140. Thus, the piston total length (L1) can be achieved that can suppress the increase in sliding loss and ensure a good sealing length (L2).

[0152] If the ratio L1 / D is less than 0.8, the total piston length (L1) becomes relatively short when low-viscosity oil is used as the refrigeration oil 180. As a result, a sufficient sealing length (L2) cannot be ensured, and therefore, not only the size of the area sealed by the oil film itself becomes insufficient, but also the viscosity (F1) of the oil film based on the above formula (1) cannot be increased.

[0153] On the other hand, for example Figure 3B As shown in the conventional piston 240, if the above ratio L1 / D exceeds 1.0, when using low-viscosity oil as the refrigeration oil 180, the piston total length (L1) becomes too large. As a result, there is a possibility of increasing the sliding loss of the cylinder sliding part. If the sliding loss becomes large, it is difficult to achieve a good coefficient of performance (COP).

[0154] Here, in the present invention, since low-viscosity oil is used as the refrigeration oil 180, it is preferred that the sealing length (L2) is as large as possible. Therefore, as described above, it is preferred that the piston total length L1 is also increased. However, as described above, when the piston total length (L1) becomes too large, the sliding loss of the cylinder sliding portion increases.

[0155] Therefore, in the present invention, the ratio L2 / L1 is set within the range of 0.9 to 1.0. Figure 3A As shown in the piston 140, the seal length (L2) can be relatively increased without excessively increasing the piston total length (L1). As a result, according to the above formula (1), it is possible to suppress the increase in sliding loss of the cylinder sliding part and increase the viscosity force (F1) of the oil film.

[0156] Furthermore, the seal length L2 becomes relatively larger relative to the piston total length L1, which means that the area sealed by the oil film of the refrigeration oil 180 also becomes relatively larger. Therefore, it is possible to further suppress the leakage of the refrigerant gas 181. Furthermore, when the seal length (L2) becomes larger, it is also possible to stabilize the posture of the piston 140 reciprocating in the compression chamber 133. As a result, it is also possible to further suppress the increase in sliding loss.

[0157] In contrast, for example Figure 3B As shown in the conventional piston 240, when the above ratio L2 / L1 is less than 0.9, when low-viscosity oil is used as the refrigeration oil 180, the sealing length (L2) cannot be fully ensured. Therefore, not only the viscosity (F1) of the oil film cannot be increased, but also the area sealed by the oil film becomes relatively small. Therefore, it is possible that the leakage of the refrigerant gas 181 cannot be fully suppressed. In addition, the above ratio L2 / L1 does not exceed 1.0 (because the sealing length (L2) is less than the total length (L1) of the piston).

[0158] In addition, in the present invention, the outer peripheral surface of the piston 140 may be a smooth surface without intentional unevenness, but may also be formed with, for example, an annular oil supply groove. By forming the oil supply groove on the outer peripheral surface of the piston 140, a sufficient amount of the refrigeration oil 180 can be supplied to the sealing area of ​​the piston 140, especially when low-viscosity oil is used as the refrigeration oil 180.

[0159] The specific structure of the annular oil supply groove is not particularly limited. For example, the number of oil supply grooves is not particularly limited, and one can be representatively exemplified. Of course, more than two oil supply grooves can also be formed. In addition, the width of the oil supply groove is not particularly limited, and can be exemplified in the range of 0.1 to 0.5 mm.

[0160] If the width of the oil supply groove is less than 0.1 mm, even if the refrigeration oil 180 is low-viscosity oil, it is difficult to supply sufficient refrigeration oil 180 to the sealed area. On the other hand, when the width of the oil supply groove exceeds 0.5 mm, if the refrigeration oil 180 is low-viscosity oil, the width of the oil supply groove is too wide and the refrigeration oil 180 flows out of the sealed area, making it difficult to maintain an appropriate amount of refrigeration oil 180 in the sealed area.

[0161] Here, for the sake of convenience, when the rotation frequency is controlled to be between 16 r / s and 35 r / s, the structure in which the average speed of the reciprocating motion of the piston 140 (the average piston speed) is set to be more than 0.31 m / s is referred to as the "high-speed structure for the average piston speed (V)", and the structure in which the ratio S / D of the reciprocating motion stroke (S) of the piston 140 to the piston diameter (D) is set within the range of 0.78 to 1.00 is referred to as the "setting structure for the ratio S / D", and the ratio S / D of the reciprocating motion stroke (S) of the piston 140 to the piston diameter (D) is referred to as the "setting structure for the ratio S / D". When the ratio L1 / D of the total length of the piston (L1) to the piston diameter (D) is set in the range of 0.8 to 1.0, and the ratio L2 / L1 of the sealing length (L2) to the total length of the piston (L1) is set in the range of 0.9 to 1.0, the structure is referred to as "the setting structure of the ratio L1 / D and the ratio L2 / L1", the high-speed structure of the piston average speed (V), the setting structure of the ratio S / D, and the setting structure of the ratio L1 / D and the ratio L2 / L1 can be independently applied to the refrigerant compressor 100.

[0162] That is, in the refrigerant compressor 100 of the present invention, by applying a high-speed structure for the average piston speed (V), a setting structure for the S / D ratio, and at least any one of the setting structures for the L1 / D ratio and the L2 / L1 ratio, even when low-viscosity oil is used as the refrigeration oil 180, the leakage of the refrigerant gas 181 can be well suppressed, thereby achieving a better coefficient of performance (COP).

[0163] Thus, in the sealed refrigerant compressor of the first embodiment, as the refrigerating machine oil 180, a refrigerating machine oil having a kinematic viscosity of 1.0 mm / s at 40° C. is used. 2 / s~2.5mm 2 / s, when a low viscosity oil is used, for example, if a controller is included to control the operating frequency of the refrigerant compressor 100, when the operating frequency is controlled to be greater than 16r / s and less than 35r / s by the controller, the average reciprocating speed of the piston 140 can be set to a structure exceeding 0.31m / s.

[0164] Alternatively, in the sealed refrigerant compressor of the present embodiment 1, when the above-mentioned low-viscosity oil is used as the refrigeration oil, the structure can be such that the ratio S / D of the stroke amount (S) of the reciprocating motion of the piston 140 to the piston diameter (D) is within the range of 0.78 to 1.00.

[0165] Alternatively, in the sealed refrigerant compressor of the present embodiment 1, it can also be constructed that, when the above-mentioned low-viscosity oil is used as the refrigeration oil 180, when the piston 140 forms the length of the sealed area in the compression chamber 133 as the sealing length (L2) through its reciprocating motion, the ratio L1 / D of the total length of the piston (L1) to the piston diameter (D) is in the range of 0.8 to 1.0, and the ratio L2 / L1 of the sealing length (L2) to the total length of the piston (L1) is in the range of 0.9 to 1.0.

[0166] If the sealed refrigerant compressor has these structures, when low-viscosity oil is used as refrigeration oil 180, leakage of refrigerant gas 181 from between piston 140 and compression chamber 133 can be further suppressed. Therefore, the coefficient of performance (COP) of the sealed refrigerant compressor can be further improved.

[0167] (Implementation Method 2)

[0168] The basic structure of the sealed refrigerant compressor of the second embodiment is the same as that of the sealed refrigerant compressor of the first embodiment, but the main shaft sliding portion (the sliding portion composed of the main shaft 124 of the crankshaft 120 and the main bearing 134) has a further characteristic structure. Figure 1 The structures shown are the same, so their detailed description is omitted.

[0169] [Spindle sliding part]

[0170] Reference Figure 4A to Figure 4C An example of a specific structure of the main shaft sliding portion in the second embodiment will be described in detail. Figure 4A It means in Figure 1 FIG. 1 is a schematic diagram showing an example of a structure in which a crankshaft 120 included in a refrigerant compressor 100 has a single sliding surface. Figure 4B and Figure 4C This is a schematic diagram showing an example of a structure in which the sliding surface of the crankshaft 120 is divided into a plurality of surfaces.

[0171] exist Figure 1 In the hermetic refrigerant compressor shown, the main shaft 124 of the crankshaft 120 as the shaft portion has a first sliding surface 126a and a second sliding surface 126b. Therefore, it can be said that the sliding surface of the main shaft 124 is divided into a plurality of surfaces. Figure 1 The structure of the main shaft 124 shown, that is, the structure in which the sliding surface is divided into two surfaces corresponds to Figure 4B The shaft portion of the present invention is not limited to this, and may also be a single surface. For example, Figure 4AAs shown, the outer peripheral surface of the main shaft 124 may not be divided into a plurality of sliding surfaces, but may have a structure with only a single sliding surface 126 .

[0172] The specific structure of dividing the sliding surface into a plurality of parts is not particularly limited, and typically, a concave portion that is concave toward the central axis side of the sliding surface is formed between the plurality of sliding surfaces. Figure 1 and Figure 4B As shown, the recessed portion constitutes the non-sliding outer peripheral surface 127. The specific shape of the recessed portion is not particularly limited, and for example, the depth thereof can be any depth as long as it does not affect the rigidity and strength of the main shaft 124. Similarly, the width of the recessed portion (i.e., the interval between the plurality of sliding surfaces) is not particularly limited, and can be appropriately set according to the degree to which the width (sliding area) of the sliding surface is narrowed (reduced or reduced).

[0173] When the sliding surface is divided into a plurality of sliding surfaces, the number of the sliding surfaces is not particularly limited. Figure 1 and Figure 4B As shown, it can be divided into a total of two surfaces, namely, the first sliding surface 126a and the second sliding surface 126b, or it can be divided into two surfaces, namely, the first sliding surface 126a and the second sliding surface 126b. Figure 4C As shown, the first sliding surface 126c, the second sliding surface 126d and the third sliding surface 126e are divided into three surfaces in total, and can also be divided into four or more surfaces. Figure 4C In the illustrated structure, the first non-sliding outer peripheral surface 127a, which is a recessed portion similar to the non-sliding outer peripheral surface 127, is located between the first sliding surface 126c and the second sliding surface 126d, and the second non-sliding outer peripheral surface 127b is located between the second sliding surface 126d and the third sliding surface 126e.

[0174] Here, in the second embodiment, in the main shaft sliding portion, by making the ratio of the axial length of the sliding surface relative to the outer diameter (diameter) of the portion forming the sliding surface less than a predetermined value, the sliding area can be reduced without substantially affecting the wear resistance.

[0175] Specifically, when the sliding surface is a single surface (for example, see Figure 4A ), the axial length of the sliding surface is set as a single sliding length T, and the sliding surface is divided into multiple surfaces (for example, Figure 4B or Figure 4C ), the axial length of the sliding surface with the shortest axial length is set as a single sliding length T. And, when the outer diameter (diameter) of the portion of the shaft portion that becomes the sliding surface is set as the outer diameter K, the shaft portion is designed in such a way that the ratio T / K of the single sliding length T to the outer diameter K of the shaft portion is less than 0.51.

[0176] exist Figure 4AIn order to facilitate the description of the outer diameter K and the single sliding length T, the length T of the single sliding surface 126 (single sliding length T) is shown larger than the outer diameter K, as shown in the figure. Figure 4A As shown, the ratio T / K exceeds 0.51. However, in practice, for example, by forming a recess (non-sliding outer peripheral surface) at the upper portion (eccentric shaft 122 side) or the lower portion (refrigerating machine oil 180 side) of the main shaft 124 when viewed from the single sliding surface 126, the ratio T / K can be set to 0.51 or less (T / K≤0.51).

[0177] exist Figure 4B In the embodiment, the sliding surface is divided into a first sliding surface 126a and a second sliding surface 126b. Figure 4B In the example shown, the axial length Ta of the upper first sliding surface 126a is smaller than the axial length Tb of the lower second sliding surface 126b (Ta<Tb). In this case, since the first sliding surface 126a becomes the "sliding surface with the shortest length", its length Ta is equivalent to the single sliding length T (T=Ta). In this example, Ta / K can be less than 0.51 in the first sliding surface 126a.

[0178] In addition, Figure 4B In, also with Figure 4A Similarly, in order to facilitate the description of the outer diameter K and the length Ta of the first sliding surface 126a, the length Ta is shown larger than the outer diameter K. In this case, the ratio T / K can be set to 0.51 or less by increasing the axial length of the non-sliding outer peripheral surface 127 or providing a non-sliding outer peripheral surface (recessed portion) not shown on the upper side of the first sliding surface 126a.

[0179] exist Figure 4C In the embodiment, the sliding surface is divided into a first sliding surface 126c, a second sliding surface 126d and a third sliding surface 126e. Figure 4C In the example shown, the length Td of the second sliding surface 126d in the center is smaller than the axial length Tc of the first sliding surface 126c on the upper side, and the length Tc is smaller than the length Te of the third sliding surface 126e on the lower side (Td<Tc<Te). In this case, the second sliding surface 126d becomes the "sliding surface with the shortest length", so its length Td is equivalent to a single sliding length T (T=Te). In this example, Te / K on the second sliding surface 126d can be less than 0.51.

[0180] In the present invention, the lower limit of the ratio T / K is not particularly limited, and as an example of a preferred lower limit, 0.15 or more can be cited. Therefore, as a preferred range of the ratio T / K in the present invention, it can be 0.15 to 0.51. In addition, as a more preferred lower limit of the ratio T / K, 0.30 can be cited, and a further preferred lower limit can be 0.42.

[0181] When the ratio T / K exceeds 0.51, a low-viscosity oil (kinematic viscosity at 40° C.: 1.0 mm 2 / s~2.5mm 2 / s), even if the later-described sulfur-based sliding modifier is added to the refrigerating machine oil 180, sufficient wear resistance cannot be obtained. On the other hand, if the ratio T / K is less than 0.15, the sliding surface may become too narrow, although it also depends on the various conditions of the shaft portion. Generally, if the ratio T / K is 0.15 or more, the sliding area will not be excessively reduced, so even if a low-viscosity oil is used as the refrigerating machine oil 180, the wear resistance of the main shaft sliding portion can be appropriately achieved by the sulfur-based sliding modifier.

[0182] Alternatively, in the second embodiment, in the main shaft sliding portion, when the sliding surface is divided into a plurality of surfaces, an axial length different from the above-mentioned single sliding length T may be specified, and the ratio of the axial length to the outer diameter (diameter) of the sliding surface may be set to a value below a specified value. Thus, the sliding area can be reduced without substantially affecting the wear resistance.

[0183] Specifically, in the present embodiment 2, when the sliding surface is divided into multiple surfaces, when the total axial length of the multiple sliding surfaces is set to the total sliding length Tt, the shaft portion can also be designed in such a way that the ratio Tt / K of the total sliding length Tt to the outer diameter K is less than or equal to 1.26 (Tt / K≤1.26).

[0184] For example, in Figure 4B In the example shown, the sum of the length Ta of the first sliding surface 126a and the length Tb of the second sliding surface 126b is the total sliding length Tt (Tt = Ta + Tb). Therefore, in this example, Ta + Tb ≤ 1.26 is sufficient. Figure 4C In the example shown, the sum of the length Tc of the first sliding surface 126c, the length Td of the second sliding surface 126d, and the length Tf of the third sliding surface 126e is the total sliding length Tt (Tt=Tc+Td+Te). Therefore, in this example, Tc+Td+Te≤1.26 is sufficient.

[0185] In addition, for convenience, when the structure of T / K≤0.51 based on the above-mentioned ratio of the single sliding length T is set as the "first structure of the main shaft sliding part", and the structure of Tt / K≤1.26 based on the above-mentioned total sliding length Tt is set as the "second structure of the main shaft sliding part", only the first structure can be combined with the characteristic structure in Embodiment 1, or only the second structure can be combined with the characteristic structure in Embodiment 1. Alternatively, both the first structure and the second structure can be combined with the characteristic structure in Embodiment 1.

[0186] Figure 4A This is an example of applying the first structure to the spindle sliding part. Figure 4B and Figure 4C The case where both the first structure and the second structure are applied to the spindle sliding portion is exemplified, but the present invention is of course not limited to Figure 4A to Figure 4C As described above, the spindle sliding portion can only apply the second structure.

[0187] In this way, when the sliding surface is a plurality of surfaces, if the ratio T / K is 0.51 or less and the ratio Tt / K is 1.26 or less, when using a low viscosity oil (kinematic viscosity at 40°C is 1.0 mm 2 / s~2.5mm 2 / s range) as refrigerating machine oil 180 to reduce the sliding area, the wear resistance of the main shaft sliding part can be further improved by the sulfur-based sliding property modifier described later.

[0188] In the present invention, the lower limit of the ratio Tt / K is not particularly limited, and as an example of a preferred lower limit, 0.3 or more can be cited. Therefore, as a preferred range of the ratio Tt / K in the present invention, the range of 0.3 to 1.26 can be cited. In addition, as a more preferred lower limit of the ratio Tt / K, 0.60 can be cited, and a further preferred lower limit can be cited as 0.99. In general, if the ratio Tt / K is greater than 0.3, the sliding area will not be excessively reduced even when the sliding surface is divided into multiple surfaces. Therefore, even if a low-viscosity oil is used as the refrigeration oil 180, the wear resistance of the main shaft sliding portion can be appropriately achieved by a sulfur-based sliding modifier.

[0189] In addition, Figure 4A to Figure 4C In the example shown, the ratio T / K or the ratio Tt / K is described for the main shaft 124 of the crankshaft 120 as the shaft portion, but the present invention is not limited thereto, and the same applies to the eccentric shaft 122. In the second embodiment, as described in the first embodiment, the connection portion between the eccentric shaft 122 and the connection mechanism 142 becomes a sliding portion, in other words, a portion of the connection mechanism 142 that connects the eccentric shaft 122 in a slidable manner corresponds to the "eccentric bearing".

[0190] Therefore, when the sliding surface of the eccentric shaft 122 and the "eccentric bearing" (the connection portion between the eccentric shaft 122 and the connection mechanism 142) is a single surface, when the axial length of the sliding surface is set to a single sliding length T, or when the sliding surface of the eccentric shaft 122 is divided into a plurality of surfaces, when the axial length of the sliding surface with the smallest axial length is set to a single sliding length T, the ratio T / K of the single sliding length T to the outer diameter K of the eccentric shaft 122 may be 0.51 or less. In addition, when the total axial lengths of the plurality of sliding surfaces of the eccentric shaft 122 are set to a total sliding length Tt, the ratio Tt / K of the total sliding length Tt to the outer diameter K of the eccentric shaft 122 may be 1.26 or less.

[0191] Therefore, in the second embodiment, in the refrigerant compressor 100, it is sufficient to satisfy the "first structure" that the ratio T / K is 0.51 or less in at least one of the main shaft 124 and the eccentric shaft 122 as the shaft portion. Alternatively, it is sufficient to satisfy the "second structure" that the ratio Tt / K is 1.26 or less in at least one of the main shaft 124 and the eccentric shaft 122. Furthermore, it is also possible to satisfy both the first structure and the second structure in at least one of the main shaft 124 and the eccentric shaft 122.

[0192] Therefore, when the sliding portion formed by the connection portion of the eccentric shaft 122 and the connection mechanism 142 is set as the "eccentric shaft sliding portion", the "main shaft sliding portion" in the description of the second embodiment can be replaced by the "eccentric shaft sliding portion". In addition, when the first structure or the second structure described above is applied to the eccentric shaft sliding portion, it can also be expressed as the "first structure of the eccentric shaft sliding portion" or the "second structure of the eccentric shaft sliding portion".

[0193] [Sulfur-based slip modifiers]

[0194] As for the refrigerating machine oil 180 used in the second embodiment, as described in the first embodiment, a refrigerating machine oil having a kinematic viscosity of 1.0 mm at 40° C. is used. 2 / s~2.5mm 2 A low viscosity oil in the range of 0.1 / s may be used. A more specific structure of the refrigerating machine oil 180 in the present invention will be described in the embodiments described later.

[0195] Here, in the second embodiment, the low-viscosity oil as the refrigeration oil 180 contains a sulfur-based sliding property modifier. As described in the first embodiment, in the refrigerant compressor 100 of the present invention, the crankshaft 120 is made of an iron-based material. The specific type of the iron-based material is not particularly limited, and examples thereof include metal materials containing iron as a main component, such as various well-known cast irons and steel materials. As the sulfur-based sliding property modifier, any substance that can react with sulfur can be used.

[0196] Therefore, the sliding property modifier in the second embodiment may be sulfur itself or a sulfur compound containing sulfur and capable of reacting with an iron-based material. For example, examples of the sulfur compound that can be used as the sliding property modifier include olefin sulfide, sulfide (e.g., diphenyl (bis) sulfide (DBDS) etc.), xanthate, thiadiazole, thiocarbonate, sulfurized oil, sulfurized ester, dithiocarbamate, sulfurized terpene, etc.

[0197] The content of the sulfur-based sliding modifier in the refrigerating machine oil 180 is not particularly limited. Typically, the sliding modifier is added to the refrigerating machine oil 180 so that the amount is 100 ppm or more when converted to the weight (mass) of the sulfur element. The lower limit of the amount (content) of the sliding modifier added such that the amount is 100 ppm when converted to the weight of the sulfur element is greater than the upper limit of the general amount of addition of the sulfur-based extreme pressure additive described later.

[0198] If the content (addition amount) of the sliding property modifier is less than 100 ppm when converted to the weight of sulfur element, then, although it depends on various conditions, when a low-viscosity refrigeration oil is used as the refrigeration oil 180, the sliding area of ​​the main shaft sliding part is reduced, and sometimes the appropriate wear resistance of the main shaft sliding part cannot be achieved. In addition, as the lower limit of the preferred content of the sulfur-based sliding property modifier, for example, 150 ppm or more when converted to the weight of sulfur element can be exemplified. In addition, as the upper limit of the preferred content of the sulfur-based sliding property modifier, for example, 1000 ppm or less when converted to the weight of sulfur element can be exemplified, and more preferably 500 ppm or less.

[0199] The sulfur-based sliding modifier used in the present invention can use the same compound as the known sulfur-based extreme pressure additive, can use a substance that has a relatively higher reactivity with the shaft material than the known extreme pressure additive, or can be added to the refrigeration oil 180 in an amount greater than the general addition amount (content) of the known extreme pressure additive.

[0200] Typically, extreme pressure additives are compounds containing active elements such as sulfur, halogen elements, and phosphorus, which react chemically with the material surface (sliding surface) constituting the sliding part to form a coating, which is used to suppress wear, sintering, fusion, etc. of the sliding parts. However, it is known that compounds containing sulfur easily react with copper.

[0201] In the refrigerant compressor 100, copper wire is used as the winding of the electric component 104. In addition, in the refrigeration and freezing device using the refrigerant compressor 100, copper pipes are usually used as refrigerant piping. As described above, copper reacts with compounds containing sulfur and is easily corroded. Therefore, when using sulfur-based extreme pressure additives, it is necessary to take measures to avoid or suppress the corrosion of copper parts (or copper-containing parts) of the refrigerant compressor 100 or the refrigeration / freezing device without reducing its reliability.

[0202] Therefore, in the technical common sense in the field of refrigerant compressor 100, it is known that a method of using a specific compound in combination is used to prevent the sulfur-based extreme pressure additive from reacting with the copper parts or copper-containing parts included in the refrigerant compressor 100 or the refrigeration / refrigeration device. Alternatively, it is also known that a sulfur-based compound is not used as an additive in the first place.

[0203] In contrast, the results of in-depth research conducted by the inventors, including experimental verification, have shown that when a low-viscosity refrigeration oil is used as the refrigeration oil 180 and the sliding area of ​​the main shaft sliding portion is reduced in a manner such that the above-mentioned ratio T / K is less than 0.51 (the first structure of the main shaft sliding portion) or the above-mentioned ratio Tt / K is less than 1.26 (the second structure of the main shaft sliding portion), a more reactive sulfur compound is used as a sliding modifier, or the added amount (content) is increased, thereby not only achieving good wear resistance but also substantially avoiding corrosion of copper components (or copper-containing components).

[0204] Furthermore, it is well known in the field of lubricating oils that a sliding property improver and an extreme pressure additive are clearly different components.

[0205] When the oil film breaks in the sliding part and the metal contact between the sliding parts occurs, the surface layer (such as the oxide layer) is removed from the contact part of each sliding surface to generate metal protrusions. These metal protrusions generated on the sliding surface may fuse with each other. The sliding modifier forms a coating (anti-wear film) to replace the removed surface layer. In this way, the fusion of metal protrusions can be prevented before it happens, so the wear of the sliding part can be well suppressed.

[0206] In contrast, the extreme pressure additive quickly forms a coating (extreme pressure film, EP film) instead of the removed surface layer. The EP film is firmly formed on the sliding surface compared to the anti-wear film formed by the sliding property modifier. This is because the extreme pressure additive targets the wear suppression of the sliding part in the lubrication state where the contact pressure between the sliding surfaces is relatively high and the oil film is easily broken, that is, in the "extreme pressure state".

[0207] Generally, as an additive added to the refrigerating machine oil 180 for the purpose of suppressing wear in the sliding part of the refrigerant compressor 100, an extreme pressure additive can be cited. In contrast, it is not common to add a sliding property modifier whose film forming speed is slower than that of the extreme pressure additive. However, in the second embodiment, when a sulfur-based sliding property modifier is added, it is assumed that the film is formed at a steady speed in the main shaft sliding part, so that sulfur is easily localized (non-uniformized) in the main shaft sliding part.

[0208] Therefore, even if a sulfur compound (sulfur extreme pressure additive) is added at a higher concentration than usual, not only good sliding properties can be achieved in the main shaft sliding portion, but also corrosion of copper parts (or copper-containing parts) of the refrigerant compressor 100 or the refrigeration device can be suppressed.

[0209] Thus, in the second embodiment, as the refrigerating machine oil 180, a refrigerating machine oil having a kinematic viscosity of 1.0 mm at 40° C. is used. 2 / s~2.5mm 2 In a refrigerant compressor 100 that uses low-viscosity oil in the range of 200 ℃ to 600 ℃, at least any one of the high-speed structure for increasing the average piston speed (V) described in the above-mentioned embodiment 1, the setting structure of the ratio S / D, and the setting structure of the ratio L1 / D and the ratio L2 / L1 is applied, and at least in the main shaft sliding portion, a first structure in which the ratio T / K of a single sliding length T to the outer diameter K of the shaft portion is 0.51 or less, or a second structure in which the ratio Tt / K of a total sliding length Tt to the outer diameter K of the shaft portion is 1.26 or less (or both the first structure and the second structure), and a structure in which a sulfur-based sliding modifier is used.

[0210] By applying at least one of the structures described in the first embodiment, even when low-viscosity oil is used as the refrigeration oil 180, leakage of the refrigerant gas 181 can be well suppressed, and a better coefficient of performance (COP) can be achieved in the refrigerant compressor 100. In addition, by applying the structure using the first structure or the second structure and the sulfur-based sliding modifier described in the second embodiment, the main shaft sliding part can be well lubricated and the wear of the main shaft sliding part can be well suppressed. As a result, the reliability of the refrigerant compressor 100 can be made better.

[0211] Furthermore, in the present invention, if the refrigerant compressor 100 is a structure in which the frequency conversion drive is performed, the electric component 104 may be operated at a low speed (low speed operation) or at a high speed (high speed operation). In particular, in the present invention, the operation frequency is such that the operation frequency is 16 r / s or more and 35 r / s or less. Usually, during the low speed operation, the oil supply capacity of the oil supply mechanism 125 provided on the crankshaft 120 is reduced, so there is a tendency that the supply amount of the refrigeration oil 180 to each sliding part is reduced.

[0212] In the present invention, as described in the above-mentioned embodiment 1, even in low-speed operation, the average piston speed can be increased or the viscosity of the oil film can be increased. Therefore, the increase in sliding loss in the cylinder sliding part can be suppressed, and the leakage of the refrigerant gas 181 can be suppressed. As a result, a good coefficient of performance (COP) can be achieved.

[0213] On the other hand, in the main shaft sliding part, by applying the first structure or the second structure, the sliding area between the main shaft 124 and the main bearing 134 becomes relatively small, but even if the supply amount of the refrigeration oil 180 is reduced, good wear resistance can be achieved. Therefore, the increase in the sliding loss of the main shaft sliding part can be suppressed, so a good performance coefficient (COP) can be achieved.

[0214] Therefore, by combining the structure described in the first embodiment and the structure described in the second embodiment and applying them to the refrigerant compressor 100, a better coefficient of performance (COP) can be achieved.

[0215] Furthermore, in the main shaft sliding portion, when both the first structure and the second structure are applied to the refrigerant compressor 100, the lubrication state of the main shaft sliding portion can be improved. Therefore, the coefficient of performance (COP) can be improved.

[0216] (Implementation 3)

[0217] The basic structure of the sealed refrigerant compressor of the third embodiment is the same as that of the sealed refrigerant compressor of the first embodiment, but it also has a characteristic structure regarding the thrust bearing. Figure 1 The structures shown are the same, so their detailed description is omitted.

[0218] [Thrust bearing]

[0219] Reference Figure 5 and Figure 6 An example of a specific structure of the thrust bearing in the second embodiment will be described in detail. Figure 5 and Figure 6 Both schematically indicate Figure 1A portion of a cross-sectional view of a refrigerant compressor 100 is shown. Figure 5 An example of distances P and Q set in a thrust bearing provided in the refrigerant compressor 100 and a load (main shaft load) applied to a main shaft sliding portion is schematically shown. Figure 6 An example of the main structure of a thrust bearing is schematically shown.

[0220] like Figure 1 As shown, in the refrigerant compressor 100, the main bearing 134 has a circular tubular or cylindrical shape provided in a manner extending in the up-down direction relative to the main body of the cylinder 130 extending in the "lateral direction" in the closed container 102. The main body of the main bearing 134 extends below the cylinder 130. And, as described in the above-mentioned embodiment 1, the tubular extension 137 extends above the cylinder 130. Therefore, the main body of the main bearing 134 and the tubular extension 137 have a single circular tubular or cylindrical structure.

[0221] The inner peripheral surface of the main bearing 134 is a sliding surface as described above. Figure 5 As shown in the figure, 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 the third embodiment, the main bearing 134 has a tubular extension 137 on the upper side, so 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" that extends the main bearing 134 upward.

[0222] By including such tubular extension 137 , when the upper limit of distance Q described later is defined, the overall length of main bearing 134 can be extended without increasing the overall height of refrigerant compressor 100 , thereby improving the posture of crankshaft 120 inserted into main bearing 134 during operation.

[0223] like Figure 6 As shown in FIG. 1 , the inner surface of the upper end of the tubular extension 137 may be chamfered or otherwise processed. In this case, the inner edge of the chamfered portion of the inner surface of the tubular extension 137 becomes the upper end 138 of the sliding surface of the main bearing 134. In addition, when 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 upper end 138 of the sliding surface of the main bearing 134.

[0224] And, if Figure 5As shown, when the distance between the axis of the compression chamber 133 and the lower end 139 of the sliding surface of the main bearing 134 is set to "distance P", and the distance between the axis of the compression chamber 133 and the upper end 138 of the sliding surface of the main bearing 134 is set to "distance Q", in the refrigerant compressor 100 of the present invention, even if it includes a thrust bearing such as a thrust ball bearing 210, when the distance P is in the range of 38 mm to 51 mm, the distance Q is less than 16 mm.

[0225] In the third embodiment, the refrigerant compressor 100 is provided with a thrust bearing on the thrust surface 136 of the main bearing 134. The specific structure of the thrust bearing is not particularly limited, and any rolling bearing may be used. However, in the third embodiment, as shown in FIG. Figure 1 , Figure 5 or Figure 6 As shown, a thrust ball bearing 210 is used. Figure 6 As shown, the thrust ball bearing 210 includes a lower race 206 located on the thrust surface 136, an upper race 202 located opposite to the lower race 206, and a plurality of balls 204 as rolling elements that can rollably abut therebetween. In addition, a vibration-damping member such as an elastic member may be provided between the thrust surface 136 of the main bearing 134 and the lower race 206.

[0226] The thrust ball bearing 210 is arranged on the outer peripheral side of the tubular extension 137, and a plurality of balls 204 are accommodated in a retainer 205. The upper race 202 and the lower race 206 are, for example, annular metal flat plates, arranged parallel to each other. In addition, arc-shaped grooves may also be provided on the upper race 202 and the lower race 206.

[0227] exist Figure 6 In the illustrated configuration example, the lower race 206, the balls 204, and the upper race 202 are stacked in this order on the thrust surface 136 in a mutually contacting state, and the flange 128 of the crankshaft 120 is seated on the upper surface of the upper race 202. Thus, the thrust ball bearing 210 is formed.

[0228] The thrust ball bearing 210 is a rolling bearing in which the ball 204 rolls in a state of point contact with the upper race 202 and the lower race 206. Therefore, the main shaft 124 can be rotated with less friction while supporting the load in the vertical direction by the thrust ball bearing 210. In addition, the thrust ball bearing 210 is a "ball bearing" using the ball 204 as a rolling element, but it can also be a "roller bearing" using rollers as a rolling element, or other rolling bearings.

[0229] Thus, the bearing function of the sliding bearing is changed to a rolling bearing such as the thrust ball bearing 210, thereby reducing the loss, thereby effectively improving the efficiency of the refrigerant compressor 100. However, generally, by providing a thrust bearing such as the thrust ball bearing 210, the overall height of the refrigerant compressor 100 increases.

[0230] On the other hand, in the refrigerant compressor 100 of the present invention, of the distance P and the distance Q based on the axial center of the compression chamber 133, when the distance P is within the range of 38 mm to 51 mm, the distance Q is set to be less than or equal to 16 mm.

[0231] Generally, in order to reduce the sliding loss of the spindle 124, a structure that reduces the friction coefficient at the spindle sliding portion and / or a structure that reduces the load (spindle load F2) on the spindle 124 can be used. In addition, in order to reduce the spindle load F2, a structure that reduces the distance Q and / or a structure that increases the distance P can be used.

[0232] However, when the distance P is to be increased, the overall height of the refrigerant compressor 100 needs to be increased (raised). When the overall height increases like this, the engine room (machine room) of the refrigeration and freezing device loaded with the refrigerant compressor 100 needs to be expanded, which leads to a reduction in the internal volume of the refrigeration and freezing device. Therefore, in order to reduce the main shaft load F2, it is assumed that the distance Q is reduced without changing the distance P.

[0233] However, if the distance Q is simply reduced, a method of reducing the wall thickness of the support portion of the cylinder 130 or reducing the thickness of the flange portion 128 to less than 4 mm, that is, a method of thinning the wall of (a portion of) a specific component (thin-wall method) can be considered.

[0234] However, when such a thin-wall method is adopted, deformation of other components is caused as a result. Specifically, when the support portion is thinned, the rigidity of the cylinder body 130 is reduced, and the main bearing 134 is easily deformed. When the flange portion 128 is thinned, the inclination of the eccentric shaft 122 becomes larger. In particular, the increase in the inclination of the eccentric shaft 122 caused by the thinning of the flange portion 128 is not envisioned in the prior art.

[0235] As described above, when the distance Q is reduced by a thin-wall method, the efficiency of the refrigerant compressor 100 can be improved, but the reliability of the refrigerant compressor 100 may be reduced due to deformation of specific components.

[0236] In contrast, in the third embodiment, as a result of experimental verification, it was found independently that by setting the upper limit of the distance Q to a predetermined value, i.e., 16 mm or less, both high efficiency and good reliability can be achieved even without adopting a thin-wall method.

[0237] Specifically, it is known that when the distance Q is reduced, the slight inclination (tilting angle) of the eccentric shaft 122 generated when the refrigerant compressor 100 is running contributes not only to the reliability of the refrigerant compressor 100 but also to the high efficiency. In other words, this view means that the change in the distance Q and the inclination of the eccentric shaft 122 are important factors for reducing the main shaft load F2 to achieve high efficiency and good reliability of the refrigerant compressor 100. Therefore, the inventors conducted in-depth research and found that it is important to set the upper limit of the distance Q to 16 mm or less.

[0238] In the third embodiment, when the distance P is set within the range of 38 mm to 51 mm, the distance Q can be set to less than 16 mm, or the distance Q can be set within the range of 12 mm to 16 mm (i.e., 12 mm as an example of the lower limit). Therefore, there is no need to increase (raise) the total height of the refrigerant compressor 100. As a result, not only can high efficiency be achieved while maintaining the good quality (especially reliability) of the refrigerant compressor 100, but there is no need to expand the engine room (machine room) of the refrigeration and freezing device, so the box volume of the refrigeration and freezing device can be fully ensured.

[0239] As described above, in the third embodiment, in the refrigerant compressor 100 including the thrust bearing, when the distance P affecting the overall height thereof is determined within a predetermined range, the upper limit of the distance Q between the axis of the compression chamber 133 and the upper end 138 of the sliding surface of the main bearing 134 is determined to be 16 mm. Thus, the flange portion 128 that contributes to the stability of the eccentric shaft 122 is not excessively thinned, an increase in the overall height can be avoided, and the load on the main shaft 124 can be reduced without performing special treatment on the sliding surface.

[0240] As a result, it is possible to achieve further improved efficiency without increasing the overall height of the refrigerant compressor 100. Furthermore, since the flange portion 128 is not excessively thinned, it is possible to achieve improved efficiency and good reliability.

[0241] Here, in order to reduce the sliding loss of the main shaft sliding part, it is possible to reduce the friction coefficient of the main shaft sliding part in addition to the structure of reducing the distance Q. If the friction coefficient is simply reduced, it is conceivable to reduce the viscosity of the refrigeration oil 180 as much as possible.

[0242] In the refrigerant compressor 100 of the present invention, as described in the first embodiment, a refrigerating machine oil 180 having a kinematic viscosity of 1.0 mm at 40° C. is used. 2 / s~2.5mm 2 / s range. Therefore, even if the low-viscosity oil is used as the refrigeration oil 180, the friction coefficient can be reduced. In addition, as described in the third embodiment, by setting the distance Q of the refrigerant compressor 100 to be less than 16 mm, the main shaft load F2 can be further reduced. Thus, the sliding loss of the main shaft sliding portion can be reduced.

[0243] Therefore, by combining the structure described in Embodiment 3 with the structure described in Embodiment 1, high efficiency and good reliability of the refrigerant compressor 100 can be achieved not only in the cylinder sliding portion but also in the main shaft sliding portion. As a result, the coefficient of performance (COP) of the refrigerant compressor 100 can be further improved.

[0244] Furthermore, in the third embodiment, the diameter of the piston 140, i.e., the piston diameter (D), or the inner diameter of the compression chamber 133 into which the piston 140 is inserted does not need to be particularly limited. If the distance Q is set to 16 mm or less when the distance P is within the range of 38 mm to 51 mm, it is not necessary to make the flange portion 128 excessively thin, nor is it necessary to substantially define the piston diameter (D) or the inner diameter of the compression chamber 133.

[0245] As described in the first embodiment, by setting the ratio S / D of the stroke amount (S) to the piston diameter (D) within the range of 0.78 to 1.00, the viscosity force (F1) of the oil film can be increased in the cylinder sliding portion (refer to the above formula (1)). The setting of the ratio S / D leads to a reduction in the piston diameter (D), but in the third embodiment, the piston diameter (D) may not be substantially specified. Therefore, the structure described in the third embodiment also has the advantage of being easily applicable to the structure described in the first embodiment.

[0246] In addition, according to the third embodiment, the spindle load F2 is reduced by setting the distance Q to 16 mm or less, thereby making it easy to form a good oil film during low-speed operation even if low-viscosity oil is used as the refrigeration oil 180. As described in the first embodiment, in particular, in the present invention, low-speed operation is sometimes performed with an operating frequency of 16 r / s or more and 35 r / s or less.

[0247] Therefore, when the structure described in the third embodiment is applied to the structure described in the first embodiment, it can be fully applied even in low-speed operation, thereby effectively suppressing or avoiding wear or sintering at the main shaft sliding portion. Therefore, even when the refrigerant compressor 100 is running at a low speed, the structure described in the third embodiment can be easily applied to the structure described in the first embodiment.

[0248] In addition, as described in the above-mentioned embodiment 2, by combining the structure described in the above-mentioned embodiment 1 and the structure described in the above-mentioned embodiment 2, a better coefficient of performance (COP) can be achieved in the refrigerant compressor 100. And, the structure described in the present embodiment 3 can also make the coefficient of performance (COP) better by combining it with the structure described in the above-mentioned embodiment 1. Therefore, by combining the structures described in the above-mentioned embodiment 1, the above-mentioned embodiment 2, and the present embodiment 3, an appropriate synergistic effect can be exerted with respect to the effect of achieving a good coefficient of performance (COP).

[0249] In addition, in this embodiment 3, if Figure 1 and Figure 5 As shown, an eccentric shaft 122 is provided at the upper part (upper end) of the main shaft 124, and a piston 140 is connected to the eccentric shaft 122 via a connecting mechanism 142. The piston 140 is inserted into a compression chamber 133 arranged in a horizontal direction so as to be reciprocating. That is, in the present embodiment 3, the piston 140 and the compression chamber 133 are located at the upper part of the refrigerant compressor 100. However, the structure of the refrigerant compressor 100 of the present invention is not limited thereto.

[0250] For example, although not shown, the piston 140 and the compression chamber 133 may be located at the lower part of the refrigerant compressor 100 by providing the eccentric shaft 122 at the lower part (lower end) of the main shaft 124. In this case, the distance P is the distance between the axis of the compression chamber 133 and the upper end of the sliding surface, and the distance Q is the distance between the axis of the compression chamber 133 and the lower end of the sliding surface.

[0251] Alternatively, in this embodiment 3, Figure 1 As shown, the crankshaft 120 extends in the "longitudinal direction" (vertical direction) of the refrigerant compressor 100, so the main shaft 124 and the eccentric shaft 122 also extend in the vertical direction. However, the structure of the refrigerant compressor 100 of the present invention is not limited to this. For example, the crankshaft 120 may also extend in the "lateral direction" (direction orthogonal to the longitudinal direction), and the piston 140 and the compression chamber 133 may not be in the longitudinal direction in the refrigerant compressor 100 but biased in the lateral direction. In this case, the two ends of the sliding surface that serve as the reference of the distance P and the distance Q are not located in the longitudinal direction but in the lateral direction.

[0252] Therefore, in the present invention, in the sliding surface of the main bearing 134, the end on the compression chamber 133 (or eccentric shaft 122) side is defined as the first end, and the end on the opposite side is defined as the second end. Therefore, the distance P can be defined as the distance between the axis of the compression chamber 133 and the second end of the sliding surface of the main bearing 134, and the distance Q can be defined as the distance between the axis of the compression chamber 133 and the first end of the sliding surface of the main bearing 134. Figure 1 or Figure 5 In the example shown), the upper end 138 of the sliding surface becomes the first end, and the lower end 139 of the sliding surface becomes the second end.

[0253] In addition, the refrigeration oil 180 used in the third embodiment can be any low-viscosity oil as described above. As described in the fourth embodiment described later, the low-viscosity oil can be an oil containing a high molecular weight component (a suitable oil described later). If such a suitable oil is used, a better oil film can be formed on the sliding portion. Thus, the effects obtained by the structure described in the third embodiment and the effects obtained by the structure described in the first embodiment can be further improved (when the structure described in the second embodiment is applied, the effects can also be further improved).

[0254] (Implementation 4)

[0255] The basic structure of the sealed refrigerant compressor of the present embodiment 4 is the same as at least any one of the sealed refrigerant compressors of the above-mentioned embodiments 1 to 3, but the low-viscosity oil used as the refrigerating machine oil 180 also has a characteristic structure. In addition, in the present embodiment 4, a specific structural example is described with respect to the refrigerating machine oil 180 that can be applied to the refrigerant compressor 100 described in any one of the above-mentioned embodiments 1 to 3. Therefore, the specific description related to the refrigerant compressor 100 is omitted.

[0256] As the refrigerating machine oil 180 of the present invention, as described above, the kinetic viscosity at 40° C. is 1.0 mm 2 / s~2.5mm 2 As a representative refrigeration oil 180, for example, at least one oily substance selected from mineral oil, alkylbenzene oil and ester oil can be preferably used. As a representative oily substance, as mentioned above, mineral oil can be exemplified.

[0257] These oily substances may be used alone or in combination of two or more thereof. The combination of two or more oily substances mentioned here includes, for example, not only the combination of two or more different oily substances equivalent to mineral oils, but also the combination of one or more oily substances equivalent to mineral oils, one or more oily substances equivalent to alkylbenzene oils (or one or more oily substances equivalent to ester oils).

[0258] The refrigerator oil 180 of the present invention may contain various known additives in addition to the above-mentioned oily substances. As such additives, various additives known in the field of refrigerator oil 180 may be preferably used, representative examples of which include sliding modifiers, extreme pressure additives, oiliness agents, antioxidants, acid scavengers, metal passivators, defoamers, corrosion inhibitors, or dispersants.

[0259] In particular, in the above-mentioned second embodiment, a sulfur-based sliding modifier is added to the low-viscosity oil used as the refrigeration oil 180, but a known extreme pressure additive may be further added. As a specific extreme pressure additive, a known extreme pressure additive may be preferably used, without particular limitation, and examples thereof include phosphorus compounds such as phosphate esters, halogenated compounds such as chlorine hydrocarbons or fluorine hydrocarbons, etc. These extreme pressure additives may be added to the low-viscosity oil (oily substance) by only one kind, or two or more kinds may be added in appropriate combination.

[0260] Among these extreme pressure additives, phosphorus compounds can be preferably used. As representative phosphorus compounds, tricresyl phosphate (TCP), tributyl phosphate (TBP), and triphenyl phosphate (TPP) can be exemplified, among which TCP can be more preferably used. In particular, if the structure described in the above-mentioned embodiment 2 is used, by adding a sulfur-based sliding modifier and a phosphorus-based extreme pressure additive to the refrigeration oil 180, good wear reduction can be achieved on the main shaft sliding portion.

[0261] The amount of the extreme pressure additive added to the low viscosity oil is not particularly limited. For example, when the refrigeration oil 180 (oily substance) is a low polar substance such as mineral oil or alkylbenzene oil, the amount can be, for example, in the range of 0.5 to 8.0% by mass, or in the range of 1 to 3% by mass, when the total mass of the low viscosity oil is set to 100% by mass.

[0262] In addition, a sliding property modifier, an extreme pressure additive, or other additives may be added to the refrigerating machine oil 180 used in the configuration described in the above embodiment 1 or the above embodiment 3. These additives may be added to the refrigerating machine oil 180 of the present invention within a range that does not hinder the effects obtained by the configuration described in the above embodiments 1 to 3 and that can obtain the effects of the additives.

[0263] In other words, the refrigeration oil 180 used in the refrigerant compressor 100 of the present invention has a kinematic viscosity of 1.0 mm / s at 40°C. 2 / s~2.5mm 2 / s. When two or more oily substances are used to form the "oil composition", the kinematic viscosity of the oil composition at 40°C is sufficient. In addition, the refrigeration oil 180 of the present invention may also be an "oil composition" that contains, in addition to one or more oily substances, a sulfur-based sliding modifier (or other sliding modifier), a phosphorus-based extreme pressure additive (or other extreme pressure additive), or other additives.

[0264] Therefore, in the present invention, the oil composition used as the refrigerating machine oil 180 can be said to have a kinematic viscosity of 1.0 mm at 40°C. 2 / s~2.5mm 2 "Low viscosity oil" in the range of 0.1477 W / s.

[0265] Furthermore, the oily substance used in the refrigerating machine oil 180 of the present invention can be used as long as its molecular weight falls within a specified range. Specifically, the number average molecular weight Mn of the oily substance used as the refrigerating machine oil 180 can be 150 to 400. In addition, the weight average molecular weight Mw (or mass average molecular weight) of the oily substance can be 150 to 400, and can be in the range of 200 to 300.

[0266] Furthermore, the polydispersity (PDI) of the oily substance, i.e., Mw / Mn, which is the ratio of the number average molecular weight Mn to the weight average molecular weight Mw, can be in the range of 1.0 to 1.1. In addition, the measuring method of the oily substance and the molecular weight (number average molecular weight Mn and weight average molecular weight Mw) described later is not particularly limited, and in the present invention, the standard polystyrene conversion based on the GPC (Gel Permeation Chromatography) method can be exemplified.

[0267] Generally speaking, when the viscosity of the oily substance used as the refrigeration oil 180 is reduced, the molecules of the oily substance are reduced in molecular weight. When such a low-molecular-weight oily substance comes into contact with the resin material present inside the refrigerant compressor 100, there is a concern that "deterioration of extractability" such as components (extractable components) contained in the resin material are more easily extracted.

[0268] In contrast, if at least the polydispersity Mw / Mn of the oily substance is within the range of 1.0 to 1.1, the deviation of the molecular weight of the oily substance becomes smaller, so that the molecular weight of the oily substance can be suppressed from becoming excessively smaller. Therefore, the "deterioration of the extractability" in the refrigerating machine oil 180, that is, the possibility of the refrigerating machine oil 180 extracting extractable components from the resin material used in the refrigerant compressor 100, can be greatly suppressed.

[0269] The "deterioration of extractability" in the refrigeration oil 180 is that the low-viscosity oil used as the refrigeration oil 180 is mixed with extractable components extracted from the resin material, and as a result, the quality of the refrigeration oil 180 may be reduced. When the quality of the refrigeration oil 180 is reduced, not only may the cylinder sliding part or the main shaft sliding part not be well lubricated, but there is also the possibility that a good oil film may not be formed on the cylinder sliding part. In this case, it may not be possible to effectively suppress the leakage of the refrigerant gas 181 from the piston 140-cylinder 132. Therefore, the molecular weight and polydispersity of the low-viscosity oil (its main component, i.e., the oily substance) used as the refrigeration oil 180 only need to be within the above-mentioned range.

[0270] Furthermore, the refrigerating machine oil 180 of the present invention may contain a component with a relatively large molecular weight, i.e., a high molecular weight component, in addition to the oily substance, as described in the above-mentioned embodiment 3. Therefore, the refrigerating machine oil 180 of the present invention may be, for example, an "oil composition" containing an oily substance having a molecular weight within the above-mentioned specified range as a main component and a high molecular weight component.

[0271] In the present invention, the oil composition (low-viscosity oil) serving as the refrigeration oil 180 is not limited to the one containing high molecular weight components, and therefore, in the following description, the oil composition containing high molecular weight components is referred to as "suitable oil" for the sake of convenience.

[0272] The high molecular weight component contained in the suitable oil may have a weight average molecular weight Mw (mass average molecular weight) of at least 500. When the total mass of the oil composition used as the refrigerating machine oil 180 is 100 mass %, the content of the high molecular weight component may be at least 0.5 mass %.

[0273] In the present embodiment 4, the suitable oil used as the refrigeration oil 180 may contain a high molecular weight component, or may be a composition in which an oily substance equivalent to the high molecular weight component is added in a manner of becoming 0.5 mass % or more. As an example of the former, mineral oil may be cited as an example. When preparing (manufacturing) a suitable oil by refining an unrefined or roughly refined raw mineral oil, it is sufficient to adjust the refining conditions or refining method of the raw oil in a manner in which a high molecular weight component of more than 0.5 mass % remains. As an example of the latter, mineral oil, alkylbenzene oil or polyalkylene glycol oil may be cited as the "main component" of a suitable oil, and an oily substance that becomes a high molecular weight component is added as an "additive component" relative to the main component.

[0274] The molecular weight and polydispersity of the oily substance as the main component of the suitable oil only need to be within the above range. If the molecular weight and polydispersity of the suitable oil are within this range, when the high molecular weight component is contained in an amount of 0.5 mass % or more, particularly in the structure of the thrust bearing described in the above embodiment 3, when the distance Q is set to 16 mm or less, an appropriate oil film can be formed on the main shaft sliding portion.

[0275] In addition, the upper limit of the content of the high molecular weight component is not particularly limited as long as it does not affect the function or effect of the oil as suitable. However, as a representative example of the upper limit of the content of the high molecular weight component, 7.0 mass % or less, 6.0 mass % or less, and 5.0 mass % can be given as an example.

[0276] Although it depends on various conditions such as the specific structure of the refrigerant compressor 100 and the specific composition of the refrigeration oil 180, when the content of the high molecular weight component exceeds 7.0 mass %, it may affect the viscosity of the oil (oil composition) used as the refrigeration oil 180. In this case, the kinematic viscosity of the oil (oil composition) at 40°C may exceed 1.0 mm 2 / s~2.5mm 2 Therefore, there is a possibility that the effect of improving the coefficient of performance (COP) corresponding to the content of the high molecular weight component cannot be obtained.

[0277] In addition, as a reason why the coefficient of performance (COP) of the refrigerant compressor 100 is improved by the inclusion of a high molecular weight component in the suitable oil, it is considered that this is because the suitable oil has a low viscosity (kinematic viscosity at 40° C. is 1.0 mm / s). 2 / s~2.5mm 2 / s), and the high molecular weight component also contributes to forming a good oil film in the sliding part. Therefore, it is considered that when a suitable oil containing a high molecular weight component is used as the refrigeration oil 180, a better oil film is formed not only in the main shaft sliding part but also in the cylinder sliding part. Therefore, not only can good lubrication of these sliding parts be achieved, but also further suppression of leakage of the refrigerant gas 181 in the cylinder sliding part can be expected.

[0278] When the suitable oil is a composition 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 weight average molecular weight Mw of 500 or more. For example, when the main component is mineral oil, mineral oil can be used as the high molecular weight component in the same manner, alkylbenzene oil can be used, polyalkylene glycol oil can be used, and other oily substances can be used.

[0279] In addition, when the oil suitable for is a material (oil composition) in which a high molecular weight component as an additive is added to an oily substance as a main component, for example, one oily substance can be used as the main component, and one oily substance different from the main component can be used as the high molecular weight component. Alternatively, two or more oily substances can be used as the main component, and one oily substance can be used as the high molecular weight component, or one oily substance can be used as the main component, and two or more oily substances can be used as the high molecular weight component. Alternatively, a mixture of two or more oily substances having a high molecular weight component added to the main component can be further mixed.

[0280] As described above, in the refrigeration oil 180 of the present embodiment 4, for one or more oily substances as the main component, a sliding property modifier (e.g., sulfur or sulfur-containing compounds), an extreme pressure additive (e.g., a phosphorus-containing compound), or other known additives may be contained. Here, when a suitable oil containing a high molecular weight component is used as the refrigeration oil 180, an oiliness agent may be particularly added as an additive. By containing an oiliness agent in a suitable oil, it is easier to form an oil film formed by a suitable oil on the sliding surface of the sliding portion. As a result, the low friction of the sliding portion can be more appropriately achieved, and the leakage of the refrigerant gas 181 can also be suppressed in the cylinder sliding portion.

[0281] The specific type of the oiliness agent is not particularly limited, and representative examples include higher fatty acids, higher alcohols, esters (ester compounds), ethers, amines, amides, metal soaps, etc. These oiliness agents may be used alone or in combination of two or more. The amount of the oiliness agent added is not particularly limited, and when the total mass of the suitable oil (oil composition) is set to 100 mass%, for example, it can be in the range of 0.01 to 1 mass%.

[0282] Among the above-mentioned oiliness agents, ester compounds can be cited as particularly representative oiliness agents. The ester compounds can be compounds having an ester structure formed by reacting an alcohol with a carboxylic acid. The alcohol can be monovalent or a polyol with a valency of more than two. Similarly, the carboxylic acid can be a monocarboxylic acid, a dicarboxylic acid, or a tricarboxylic acid (which can also have more than four carboxyl groups). In general, commercially available ester oiliness agents can be preferably used.

[0283] If the suitable oil is an oil composition containing an oiliness agent, the ability to form an oil film can be further improved. That is, since the suitable oil contains a high molecular weight component, it is believed that the high molecular weight component exists on the sliding surface of the sliding part (spindle sliding part or cylinder sliding part, etc.), thereby forming a good oil film. In addition, it is believed that if the suitable oil contains an oiliness agent, the oiliness agent is adsorbed on the sliding surface, thereby making it easier to form an oil film based on the suitable oil (oil composition).

[0284] In particular, if the oiliness agent is an ester compound, the oiliness agent has an ester bond. Therefore, through the polarity from the ester bond, the sliding part can be easily used to make the oil film formed based on the suitable oil (oil composition) close (improve the closeness of the oil film). As a result, the ability to form the oil film of the suitable oil can be further improved, so the friction coefficient can be further reduced, and the low friction of the sliding part can be more appropriately achieved. In addition, in the cylinder sliding part, a good oil film is easily formed between the piston 140 and the cylinder 132, so the leakage of the refrigerant gas 181 can be better suppressed.

[0285] In addition, when the refrigerator oil 180 of the fourth embodiment is the above-mentioned suitable oil, as described above, it may contain a sulfur-based sliding property modifier and a phosphorus-based extreme pressure additive as additives. When the suitable oil contains these additives, not only can the effects obtained by each additive be imparted to the suitable oil, but also a synergistic effect based on each additive can be expected, so that not only the sliding performance of each sliding part can be improved, but also the leakage of the refrigerant gas 181 in the cylinder sliding part can be well suppressed.

[0286] On the other hand, the suitable oil may not contain at least any one or all of the sulfur-based sliding modifier, phosphorus-based extreme pressure additive, and ester oiliness agent, depending on the specific structure or various conditions of the refrigerant compressor 100. In other words, the suitable oil may contain appropriate additives as required, and the specific additives are not limited to the above-mentioned sulfur-based sliding modifier, phosphorus-based extreme pressure additive, ester oiliness agent, etc. In addition, as the refrigeration oil 180, a low-viscosity oil that does not contain a high molecular weight component may also be used.

[0287] (Implementation method 5)

[0288] In this embodiment 5, referring to Figure 7 An example of a refrigeration and freezing apparatus including the refrigerant compressor 100 described in Embodiments 1 to 4 above will be described in detail.

[0289] The refrigerant compressor 100 of the present invention can be widely and appropriately applied to various equipment (refrigeration and freezing devices) having a refrigeration cycle or a structure substantially equivalent thereto. Specifically, for example, cold storage (household cold storage, business cold storage), ice maker, display cabinet, dehumidifier, heat pump water heater, heat pump washing and drying machine, vending machine, air conditioner, air compressor, etc. can be cited, but there is no particular limitation. In this embodiment 2, as an application example of the refrigerant compressor 100 of the present invention, Figure 7 The article storage device shown illustrates the basic structure of a refrigeration and freezing device.

[0290] like Figure 7As shown, the freezing and refrigerating device of the present embodiment 5 includes a main body 301, a partition wall 304, a refrigerant circuit 305, etc. The main body 301 is composed of a heat-insulating box body and a door body, etc. The box body is a structure with an opening on one side, and the door body is a structure for opening and closing the opening of the box body. The interior of the main body 301 is divided into a storage space 302 for articles and a machine room 303 by a partition wall 304. An air blower not shown in the figure is provided in the storage space 302. In addition, the interior of the main body 301 can also be divided into a space other than the storage space 302 and the machine room 303, etc.

[0291] The refrigerant circuit 305 is a structure for cooling the storage space 302, and is composed of the refrigerant compressor 100 described in each of the above embodiments, the radiator 307, the decompression device 308 and the heat absorber 309, which are connected in a ring shape by pipes. That is, the refrigerant circuit 305 is an example of a refrigeration cycle using the refrigerant compressor 100 of the present invention.

[0292] As described above, a refrigerant gas 181 such as R600a is sealed in the refrigerant compressor 100 (in the sealed container 102), and the refrigerant gas 181 is sealed in a relatively low temperature state in such a way as to have the same pressure as the low-pressure side of the freezing / refrigerating device. The specific type of the refrigerant gas 181 is not particularly limited, and a refrigerant gas of a hydrocarbon with a low global warming potential such as R600a can be preferably used.

[0293] The heat absorber 309 of the refrigerant circuit 305 is disposed in the storage space 302. The cooling heat of the heat absorber 309, such as Figure 7 As shown by the dotted arrows, the liquid is stirred by a blower (not shown) so as to circulate in the storage space 302. As a result, the storage space 302 is cooled.

[0294] Thus, the refrigerating and freezing apparatus of the fifth embodiment is equipped with the refrigerant compressor 100 of the first to fourth embodiments. The refrigerant compressor 100 has a kinematic viscosity of 1.0 mm / s at 40° C. when used as the refrigerating machine oil 180. 2 / s~2.5mm 2 When a low-viscosity oil in the range of 100 / s is used, the coefficient of performance (COP) can be further improved. Therefore, a refrigeration and freezing apparatus equipped with such a refrigerant compressor 100 can reduce its power consumption.

[0295] [Example]

[0296] The present invention will be described in more detail based on reference examples, embodiments and conventional examples, but the present invention is not limited thereto. A person skilled in the art can make various changes, modifications and alterations without departing from the scope of the present invention.

[0297] (Reference example)

[0298] In the existing refrigerant compressor, a total of four types of mineral oils (1.8 mm 2 / s, 2.5mm 2 / s, 3.3mm 2 / s and 5.0mm 2 / s) as the refrigeration oil 180 (changing the kinematic viscosity of the refrigeration oil 180), and when the operating frequency was set to 17r / s, the amount of refrigerant gas 181 leaking from the piston 140-cylinder 132 (refrigerant leakage) was evaluated. The results are shown in Figure 8 Graph of the curve.

[0299] In addition, the refrigerant leakage amount in the reference example was measured (evaluated) as follows. Figure 1 ) to block the suction hole ( Figure 1 (not shown) to modify the discharge hole ( Figure 1 A container (refrigerant container) sealed with a certain amount of refrigerant gas 181 is connected to the side (not shown in the figure) to prepare a refrigerant leakage measurement system. In this measurement system, since the suction hole is closed, the refrigerant gas 181 is introduced from the refrigerant container through the piston 140-cylinder 132 into the sealed refrigerant compressor. Therefore, in this measurement system, the pressure reduction of the refrigerant container can be used as the refrigerant leakage. In this measurement system, the refrigerant leakage when using four mineral oils with different kinematic viscosities is evaluated by operating the refrigerant compressor at an arbitrary frequency.

[0300] exist Figure 8 In the curve diagram, the horizontal axis is the kinematic viscosity of the refrigeration oil 180 at 40°C (unit: mm 2 / s), and the vertical axis is the refrigerant leakage (unit: %). Figure 8 The evaluation standard of refrigerant leakage in the refrigerant leakage test is based on the kinematic viscosity of 5.0 mm at 40 ° C. 2 The result when the refrigeration oil at 180 / s is set as 100%.

[0301] from Figure 8 The results show that in the existing refrigerant compressor, especially when running at a low speed (17r / s), as the viscosity decreases, the refrigerant leakage increases significantly.

[0302] (Evaluation method of performance coefficient)

[0303] According to the results of the reference example, in the existing refrigerant compressor, when operating at a low speed, the kinematic viscosity at 40°C is 2.5 mm 2 / s or less, the refrigerant leakage increases significantly. Therefore, in the refrigerant compressor 100 to which the high-speed structure of the piston average speed (V), the setting structure of the ratio S / D, and the setting structure of the ratio L1 / D and the ratio L2 / L1 described in the above embodiment 1 are applied, how the coefficient of performance (COP) changes is evaluated. The above structure applied to the refrigerant compressor 100 is shown in Table 1.

[0304] [Table 1]

[0305]

[0306] In addition, the coefficient of performance (COP) of the refrigerant compressor 100 of the embodiment or the conventional refrigerant compressor is calculated as the ratio of the refrigeration capacity to the consumed energy (input) (refrigeration capacity / input). The evaluation criteria for the coefficient of performance (COP) are as follows: 2 The result when the refrigeration oil at 180 / s is set as 100%.

[0307] (Example)

[0308] The refrigerant compressor 100 of the present invention to which the configuration shown in Table 1 (average piston speed, ratio S / D, ratio L1 / D, ratio L2 / L1) was applied was used, and a total of 7 types of mineral oils (1.8 mm 2 / s, 2.2mm 2 / s, 2.3mm 2 / s, 2.5mm 2 / s, 2.7mm 2 / s, 3.3mm 2 / s and 5.0mm 2 / s) as the refrigerating machine oil 180 (the kinetic viscosity of the refrigerating machine oil 180 was changed), and the coefficient of performance (COP) was evaluated.

[0309] The results when the operating frequency is 27r / s are shown in Fig. 9 The results when the operating frequency is 17r / s are shown in Fig.10 In addition, Fig. 9 and Fig.10 In the graphs, the results of the examples are represented by circular symbols. In any graph, the horizontal axis represents the kinematic viscosity of the refrigeration oil 180 at 40°C (unit: mm 2 / s), and the vertical axis is the coefficient of performance (COP).

[0310] (Existing example)

[0311] A refrigerant compressor having the same configuration as in the example was used except that the conventional refrigerant compressor, i.e., the configuration shown in Table 1, was not used, and a total of five mineral oils (1.8 mm 2 / s, 2.3mm 2 / s, 2.7mm 2 / s, 3.3mm 2 / s, and 5.0mm 2 The results when the operating frequency was 27 r / s are shown in FIG. Fig. 9 The results when the operating frequency is 17r / s are shown in Fig.10 In addition, Fig. 9 and Fig.10 In the graph of , the result of the conventional example is indicated by a cross symbol.

[0312] (Comparison between Example and Conventional Example)

[0313] like Fig. 9 As shown, when the operating frequency is 27 r / s, the coefficient of performance (COP) is improved when the kinematic viscosity of the refrigeration oil 180 is reduced in both the embodiment and the conventional example. This is because the viscous resistance of the refrigeration oil 180 is reduced, so the input power to the refrigerant compressor is reduced.

[0314] In contrast, Fig.10 As shown, when the operating frequency is lowered to 17 r / s (low speed operation), in the conventional example, when the kinematic viscosity (40° C.) of the refrigeration oil 180 is 2.5 mm 2 / s or less, the coefficient of performance (COP) decreases. This is because, as described above, when the kinematic viscosity of the refrigeration oil 180 is 2.5 mm 2 When the speed is less than 100 s, the leakage of the refrigerant gas 181 from the piston 140 to the cylinder 132 increases, and the refrigeration capacity decreases.

[0315] On the other hand, in the embodiment, even if the kinematic viscosity (40° C.) of the refrigerating machine oil 180 is 2.5 mm 2 / s or less, the coefficient of performance (COP) is also improved. Therefore, it can be seen that in the refrigerant compressor 100 (the sealed refrigerant compressor of the present invention) using the structure shown in Table 1, as the refrigeration oil 180, a refrigeration oil with a kinematic viscosity (40°C) of 1.0 mm 2 / s~2.5mm 2 When a low viscosity oil is used in the range of 0.1 / s, a good coefficient of performance (COP) can be achieved even at low speed operation.

[0316] In addition, as shown in Table 1, the average piston speed in the prior art example is 17 r / s and 0.31 m / s, but the average piston speed in the embodiment is 17 r / s and 0.34 m / s. As described above, in the embodiment, even if low-viscosity oil is used as the refrigeration oil 180, a good performance coefficient (COP) can be achieved, but in the prior art example, when low-viscosity oil is used as the refrigeration oil 180, a good performance coefficient (COP) cannot be achieved. Therefore, it can be seen that if the average piston speed exceeds at least 0.31 m / s within the range of 16 r / s to 35 r / s specified as the low-speed operation frequency in the present invention, a good performance coefficient (COP) can be achieved.

[0317] (Note)

[0318] Through the description of each embodiment above, the following technology is disclosed in this specification.

[0319] (Technology 1)

[0320] A sealed refrigerant compressor, comprising: a sealed container; a refrigeration oil stored in the sealed container, the kinematic viscosity of which is 1.0 mm at 40°C; 2 / s~2.5mm 2 / s range; a cylinder body contained in the closed container and forming a compression chamber; and a piston inserted into the interior of the compression chamber in a reciprocating manner, when the operating frequency is greater than 16r / s and less than 35r / s, the average speed of the reciprocating motion of the piston is set to exceed 0.31m / s.

[0321] (Technique 2)

[0322] According to the sealed refrigerant compressor described in technology 1, the ratio S / D of the stroke amount (S) of the reciprocating motion of the above-mentioned piston to the above-mentioned piston diameter (D) is in the range of 0.78 to 1.00.

[0323] (Technique 3)

[0324] A sealed refrigerant compressor as described in Technology 1 or Technology 2, wherein, with respect to the above-mentioned piston, when the length of the area sealed in the above-mentioned compression chamber by the reciprocating motion of the above-mentioned piston is set as a sealing length (L2), the ratio L1 / D of the above-mentioned piston total length (L1) to the above-mentioned piston diameter (D) is in the range of 0.8 to 1.0, and the ratio L2 / L1 of the above-mentioned sealing length (L2) to the above-mentioned piston total length (L1) is in the range of 0.9 to 1.0.

[0325] (Technique 4)

[0326] A sealed refrigerant compressor, comprising: a sealed container; a refrigeration oil stored in the sealed container, the kinematic viscosity of which is between 1.0 mm 2 / s~2.5mm 2 / s; a cylinder body housed in the closed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, wherein the ratio S / D of the stroke (S) of the reciprocating motion of the piston to the diameter (D) of the piston is in the range of 0.78 to 1.00.

[0327] (Technique 5)

[0328] According to the sealed refrigerant compressor described in Technology 4, with respect to the above-mentioned piston, when the length of the area sealed in the above-mentioned compression chamber by the reciprocating motion of the above-mentioned piston is set as the sealing length (L2), the ratio L2 / L1 of the above-mentioned sealing length (L2) to the above-mentioned piston total length (L1) is in the range of 0.9 to 1.0.

[0329] (Technique 6)

[0330] A sealed refrigerant compressor, comprising: a sealed container; a refrigeration oil stored in the sealed container, the kinematic viscosity of which is between 1.0 mm 2 / s~2.5mm 2 / s; a cylinder body contained in the closed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, when the ratio L1 / D of the total length of the piston to the diameter of the piston (D) is in the range of 0.8 to 1.0, and the length of the area sealed in the compression chamber by the reciprocating motion of the piston is set as a sealing length (L2), the ratio L2 / L1 of the sealing length (L2) to the total length of the piston (L1) is in the range of 0.9 to 1.0.

[0331] (Technique 7)

[0332] A sealed refrigerant compressor according to any one of Technology 1 to Technology 6, wherein the compression component includes: a crankshaft as an axis portion, having a main shaft and an eccentric shaft; and an eccentric bearing as a bearing portion for supporting the axis portion, for supporting the main shaft and the eccentric bearing, wherein the sliding surface of the main shaft and the main bearing is divided into a plurality of surfaces, and when the total axial lengths of the plurality of sliding surfaces are taken as a total sliding length Tt, a ratio Tt / K of the total sliding length Tt to an outer diameter K of the main shaft is less than 1.26.

[0333] (Technology 8)

[0334] A sealed refrigerant compressor according to any one of Technology 1 to Technology 7, wherein the compression component includes: a crankshaft as an axis portion, having a main shaft and an eccentric shaft; and an eccentric bearing as a bearing portion for supporting the axis portion, supporting the main shaft and the eccentric bearing, wherein the sliding surface of the main shaft with the main bearing is a single surface or is divided into a plurality of surfaces, and when the sliding surface is a single surface, when the axial length of the sliding surface is set to a single sliding length T, or when the sliding surface is divided into a plurality of surfaces, when the axial length of the sliding surface with the smallest axial length is set to a single sliding length T, a ratio T / K of the single sliding length T to an outer diameter K of the main shaft is less than 0.51, and in the refrigeration oil, sulfur or a compound containing sulfur is contained as a sliding property modifier.

[0335] (Technique 9)

[0336] A sealed refrigerant compressor according to any one of Technology 1 to Technology 6, wherein the compression component further includes: a crankshaft having a main shaft and an eccentric shaft; a main bearing for axially supporting the main shaft; and a thrust bearing arranged on the thrust surface of the main bearing, in the sliding surface of the main bearing, the end on the compression chamber side is set as the first end, the end on the opposite side is set as the second end, the distance between the axis of the compression chamber and the second end of the sliding surface of the main bearing is set as P, and the distance between the axis of the compression chamber and the first end of the sliding surface of the main bearing is set as Q, when the distance P is in the range of 38mm to 51mm, the distance Q is less than 16mm.

[0337] (Technology 10)

[0338] A method for operating a sealed refrigerant compressor, wherein the sealed refrigerant compressor comprises: a sealed container; a refrigeration oil stored in the sealed container, the kinetic viscosity of which is 1.0 mm at 40°C; 2 / s~2.5mm 2 / s range; a cylinder body contained in the closed container and forming a compression chamber; and a piston inserted into the interior of the compression chamber in a reciprocating manner, when its operating frequency is greater than 16r / s and less than 35r / s, the average speed of the reciprocating motion of the piston exceeds 0.31m / s.

[0339] (Technology 11)

[0340] A freezing and refrigeration device, comprising: a sealed refrigerant compressor recorded in any one of Techniques 1 to 9, or a sealed refrigerant compressor that executes the operation method recorded in Technique 9; a radiator; a pressure reducing device and a heat absorber, including a refrigerant circuit that connects them into a ring shape through piping.

[0341] The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining technical means disclosed in different embodiments and a plurality of modifications are also included in the technical scope of the present invention.

[0342] In addition, according to the above description, many improvements and other embodiments of the present invention are obvious to those skilled in the art. Therefore, the above description is only explained as an example, and is provided for the purpose of teaching the best mode for performing the present invention to those skilled in the art. The details of its structure and / or function can be substantially changed without departing from the spirit of the present invention.

[0343] Possibility of industrial application

[0344] As described above, according to the present invention, the sealed refrigerant compressor can use a refrigerator oil with a lower viscosity and achieve a better coefficient of performance (COP). Therefore, the present invention can be widely applied to various equipment using a refrigeration cycle.

[0345] Description of Reference Numerals

[0346] 100: Hermetic refrigerant compressor

[0347] 102: Sealed container

[0348] 104: Electric components

[0349] 106: Compression member

[0350] 108: Compressor body

[0351] 120: Crankshaft

[0352] 122: Eccentric shaft

[0353] 124: Spindle

[0354] 125: Oil supply mechanism

[0355] 126: Sliding surface

[0356] 126a: First sliding surface

[0357] 126b: Second sliding surface

[0358] 126c: First sliding surface

[0359] 126d: Second sliding surface

[0360] 126e: Third sliding surface

[0361] 127: Non-sliding outer surface (non-sliding surface)

[0362] 127a: First non-sliding outer peripheral surface (non-sliding surface)

[0363] 127b: Second non-sliding outer peripheral surface (non-sliding surface)

[0364] 128: Flange

[0365] 130: Cylinder

[0366] 132: Cylinder

[0367] 133: Compression Chamber

[0368] 134: Main bearing

[0369] 136: Thrust surface

[0370] 137: Tubular extension

[0371] 138: Upper end of sliding surface (first end)

[0372] 139: Lower end of sliding surface (second end)

[0373] 140: Piston

[0374] 142: Linking mechanism

[0375] 150: Stator

[0376] 152: Rotor

[0377] 180: Refrigeration oil

[0378] 181: Refrigerant gas

[0379] 190: Suspension Spring

[0380] 202: Upper seat

[0381] 204: Ball (rolling element)

[0382] 205: Retainer

[0383] 206: Lower seat

[0384] 210: Thrust ball bearing (thrust bearing)

[0385] 240: Existing piston

[0386] 301: Main body

[0387] 302: Storage Space

[0388] 303: Mechanical Room

[0389] 304: Partition wall

[0390] 305: Refrigerant circuit

[0391] 307: Radiator

[0392] 308: Pressure relief device

[0393] 309: Heat absorber.

Claims

1. A sealed refrigerant compressor, characterized in that: include: Closed container; The refrigeration oil is stored in the sealed container and has a kinematic viscosity of 1.0 mm at 40°C. 2 / s~2.5mm 2 / s range; A cylinder body contained in the sealed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, When the operating frequency is 16 r / s or more and 35 r / s or less, the average speed of the reciprocating motion of the piston is set to exceed 0.31 m / s.

2. The hermetic refrigerant compressor according to claim 1, characterized in that: The ratio S / D of the stroke amount (S) of the reciprocating motion of the piston to the piston diameter (D) is in the range of 0.78 to 1.

00.

3. The hermetic refrigerant compressor according to claim 1 or 2, characterized in that: Regarding the piston, when the length of the region in which the compression chamber is sealed due to the reciprocating motion of the piston is defined as a sealing length (L2), The ratio L1 / D of the piston total length (L1) to the piston diameter (D) is in the range of 0.8 to 1.0, And the ratio L2 / L1 of the sealing length (L2) to the entire length of the piston (L1) is in the range of 0.9 to 1.

0.

4. A sealed refrigerant compressor, characterized in that: include: Closed container; The refrigeration oil is stored in the sealed container and has a kinematic viscosity of 1.0 mm at 40°C. 2 / s~2.5mm 2 / s range; A cylinder body contained in the sealed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, The ratio S / D of the stroke amount (S) of the reciprocating motion of the piston to the piston diameter (D) is in the range of 0.78 to 1.

00.

5. The hermetic refrigerant compressor according to claim 4, characterized in that: Regarding the piston, when the length of the region in which the compression chamber is sealed due to the reciprocating motion of the piston is defined as a sealing length (L2), The ratio L2 / L1 of the sealing length (L2) to the piston overall length (L1) is in the range of 0.9 to 1.

0.

6. A sealed refrigerant compressor, characterized in that: include: Closed container; The refrigeration oil is stored in the sealed container and has a kinematic viscosity of 1.0 mm at 40°C. 2 / s~2.5mm 2 / s range; A cylinder body contained in the sealed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, When the ratio L1 / D of the piston total length (L1) to the piston diameter (D) is in the range of 0.8 to 1.0, When the length of the area sealed in the compression chamber by the reciprocating motion of the piston is set as the sealing length (L2), The ratio L2 / L1 of the sealing length (L2) to the piston total length (L1) is in the range of 0.9 to 1.

0.

7. The hermetic refrigerant compressor according to claim 1, 4 or 6, characterized in that: The compression member includes: a crankshaft as a shaft portion having a main shaft and an eccentric shaft; and a main bearing as a bearing portion for axially supporting the shaft portion, the main shaft being axially supported, and an eccentric bearing for axially supporting the eccentric bearing. The sliding surface of the main shaft and the main bearing is divided into a plurality of surfaces, and when the total axial length of the plurality of sliding surfaces is taken as a total sliding length Tt, a ratio Tt / K of the total sliding length Tt to an outer diameter K of the main shaft is 1.26 or less.

8. The hermetic refrigerant compressor according to claim 1, 4 or 6, characterized in that: The compression member includes: a crankshaft as a shaft portion having a main shaft and an eccentric shaft; and a main bearing as a bearing portion for axially supporting the shaft portion, the main shaft being axially supported, and an eccentric bearing for axially supporting the eccentric bearing. The sliding surface of the main shaft with the main bearing is a single surface or is divided into a plurality of surfaces. When the sliding surface is a single surface, when the axial length of the sliding surface is set to a single sliding length T, or when the sliding surface is divided into a plurality of surfaces, when the axial length of the sliding surface with the smallest axial length is set to a single sliding length T, a ratio T / K of the single sliding length T to an outer diameter K of the main shaft is 0.51 or less, Furthermore, the refrigerating machine oil contains sulfur or a compound containing sulfur as a sliding property improver.

9. The hermetic refrigerant compressor according to claim 1, 4 or 6, characterized in that: The compression member further includes: a crankshaft having a main shaft and an eccentric shaft; a main bearing for axially supporting the main shaft; and a thrust bearing provided on a thrust surface of the main bearing. In the sliding surface of the main bearing, the end on the compression chamber side is set as the first end, the end on the opposite side is set as the second end, the distance between the axis of the compression chamber and the second end of the sliding surface of the main bearing is set as P, and the distance between the axis of the compression chamber and the first end of the sliding surface of the main bearing is set as Q, When the distance P is within a range of 38 mm to 51 mm, the distance Q is less than or equal to 16 mm.

10. A method for operating a sealed refrigerant compressor, characterized in that: The hermetic refrigerant compressor comprises: Closed container; The refrigeration oil is stored in the sealed container and has a kinematic viscosity of 1.0 mm at 40°C. 2 / s~2.5mm 2 / s range; A cylinder body contained in the sealed container and forming a compression chamber; and a piston inserted into the compression chamber in a reciprocating manner, When the operating frequency is 16 r / s or more and 35 r / s or less, the average speed of the reciprocating motion of the piston exceeds 0.31 m / s.

11. A freezing and refrigerating device, characterized in that: A refrigerant circuit is provided, which includes the sealed refrigerant compressor according to claim 1, 4 or 6; a radiator; a pressure reducing device and a heat absorber, and these are connected in a ring shape by piping.

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