WO2020095903A1 - Refrigerant compressor and refrigeration apparatus using same - Google Patents

Abstract

This refrigerant compressor has a sealed container in which refrigerator oil is stored, wherein either a shaft part that is a main shaft and an eccentric shaft, or a bearing part that is a main bearing and an eccentric bearing, is provided with a tapered part that brings the shaft part and the bearing part into line contact in a state in which the axis of the shaft part is inclined relative to the axis of the bearing part, due to the diameter changing from the longitudinally outward side of a crankshaft toward the center in one axial end side and another axial end side of the bearing part. The ratio C/D of the diameter D of the shaft part to the clearance C between the shaft part and the bearing part is set to a value in the range of 4.0×10⁻⁴ to 3.0×10⁻³, inclusive. The taper depth d_B of the tapered part is set to a value of 2.0×10⁻³ mm or greater. The ratio G/D of the diameter D of the shaft part to the maximum gap G, which is the sum of the clearance C and the total value of the taper depth d_B in the corresponding combination of the shaft part and the bearing part, is set to a value of 4.0×10⁻³ or less.

Description

Refrigerant compressor and refrigeration apparatus using the same

The present invention relates to a refrigerant compressor used in a refrigerator, an air conditioner, etc., and a refrigeration system using the same.

As shown in the schematic sectional view of the conventional refrigerant compressor 1 of FIG. 12, the conventional refrigerant compressor 1 has, for example, a crankshaft 7 and a piston 15 connected to an eccentric shaft 9 of the crankshaft 7. A compression element 6 and an electric element 5 having a stator 3 and a rotor 4 for rotating a crankshaft 7 are housed in a closed container 11. The main shaft 8 of the crankshaft 7 is supported by a main bearing 14. Refrigerating machine oil 2 is supplied to the sliding portion in the refrigerant compressor 1.

When the refrigerant compressor 1 is driven, the crankshaft 7 is rotated together with the rotor 4 of the electric element 5 by the electric power supplied from the outside, and the eccentric movement of the eccentric shaft 9 causes the piston 15 through the connecting rod 17 and the piston pin 16. Are reciprocated in the cylinder bore 12. The piston 15 compresses the refrigerant gas supplied from the outside into the closed container 11 via the suction tube 20 in the compression chamber 13. Refrigerating machine oil 2 is supplied to each sliding portion from the oil supply pump 10 as the crankshaft 7 rotates, lubricates each sliding portion, and seals between the piston 15 and the cylinder bore 12.

In recent years, from the viewpoint of protecting the global environment, the efficiency of refrigerant compressors has been improved to reduce the amount of fossil fuel used. For example, as disclosed in Patent Document 1, a refrigerant compressor has been developed in which an insoluble film is formed on the surface of a sliding portion such as a crankshaft to prevent wear of the sliding portion.

Specifically, in the example shown in FIG. 12, the crankshaft 7 is supported by the main bearing 14 in a cantilever state. In the process of sucking and compressing the refrigerant gas into the closed container 11, the load acting on the crankshaft 7 in the radial direction fluctuates 10 times or more with respect to the minimum value. Due to the fluctuation of the load, the crankshaft 7 tends to swing around with the axis line inclined with respect to the axis line of the main bearing 14, so that the lubrication state at both axial ends of the main bearing 14 becomes relatively severe. Therefore, an insoluble coating such as a phosphate coating is formed on the surface of the main shaft 8 of the crankshaft 7 to suppress abnormal wear due to direct metal contact between the main shaft 8 and the main bearing 14.

Japanese Patent Laid-Open No. 7-238885

However, recently, it has been desired to further improve the efficiency of the refrigerant compressor. For example, expansion of the variable speed rotation range in the rotating portion of the refrigerant compressor, adoption of low-viscosity refrigerating machine oil, and reduction of the sliding area Design changes such as the above are being considered. When such a design change is made, even if an insoluble film is formed on the surface of the sliding part, the film will be abraded especially at both axial ends of the main shaft of the crankshaft where maintaining the lubrication condition is severe. Therefore, there is a possibility that the sliding portion may be worn. This reduces the durability and reliability of the refrigerant compressor.

Therefore, the present invention provides a refrigerant compressor and a refrigeration apparatus using the same, which can prevent deterioration of durability and reliability by preventing abrasion of sliding parts, and can achieve high efficiency. It is an object.

In order to solve the above problems, a refrigerant compressor according to an aspect of the present invention includes a closed container in which refrigerating machine oil is stored, an electric element housed in the closed container, and driven by electric power supplied from the outside. A compression element that is housed in the closed container and attached to the refrigerating machine oil, is driven by the electric element, and compresses a refrigerant gas supplied from the outside, and the compression elements are arranged in a longitudinal direction. A crankshaft having a main shaft and an eccentric shaft that are arranged, a main bearing that axially supports the main shaft, and an eccentric bearing that axially supports the eccentric shaft, and the shaft is at least one of the main shaft and the eccentric shaft. Part, and at least one of the main bearing and the eccentric bearing, at least one of the axial direction one end side and the other end side of the bearing part, in the longitudinal direction of the crankshaft. A taper portion is provided which causes the shaft portion and the bearing portion to come into line contact with each other in a state in which the axis of the shaft portion is inclined with respect to the axis of the bearing portion due to the diameter changing from the side to the center side. The ratio C / D of the diameter D of the shaft portion and the clearance C between the shaft portion and the bearing portion is in the range of 4.0 × 10 ⁻⁴ or more and 3.0 × 10 ⁻³ or less. And the taper depth d _B corresponding to the distance in the direction perpendicular to the axis of the bearing between the one end and the other end of the taper in the axial direction of the bearing is 2.0 × 10 ^{−. A} maximum gap G that is set to a value of ³ mm or more and is the sum of the total value of the taper depth d _B of the tapered portion and the clearance C in the corresponding combination of the shaft portion and the bearing portion; the ratio G / D of the diameter D of, 4.0 × ^{10 -3} is set with the following values That.

According to the above configuration, the ratio C / D, the taper depth d _B , and the ratio G / D are set to values in the above range, respectively, so that the shaft portion and the bearing portion are different from the diameter D of the shaft portion. The distance between them can be set appropriately, and the tapered portion having a good inclined surface can be formed. This can prevent local metal contact between the shaft portion and the bearing portion, and promote formation of an oil film between the sliding portions of the shaft portion and the bearing portion. Therefore, it is possible to provide a refrigerant compressor having excellent long-term durability, low input, and high efficiency.

A refrigerating apparatus according to an aspect of the present invention includes a refrigerant circuit in which the refrigerant compressor, a radiator that radiates the refrigerant, a decompressor that decompresses the refrigerant, and a heat absorber that absorbs the refrigerant are annularly connected by a pipe. Prepare

According to the above configuration, by including the refrigerant compressor described above, it is possible to provide a refrigeration system that can reduce power consumption, realize energy saving, and improve long-term reliability.

According to the present invention, it is possible to provide a refrigerant compressor and a refrigerating apparatus using the same, which can achieve high efficiency while preventing deterioration of durability and reliability by preventing abrasion of sliding parts. ..

It is a schematic sectional drawing of the reciprocating type (reciprocating type) refrigerant compressor concerning a 1st embodiment. It is an expanded sectional view of the E section of the refrigerant compressor of FIG. It is sectional drawing of the main components of the refrigerant compressor of FIG. FIG. 1A is a characteristic diagram showing an input ratio between the embodiment of the refrigerant compressor of FIG. 1 and a conventional example. (B) is a characteristic view showing the COP ratio of the embodiment of the refrigerant compressor of FIG. 1 and the conventional example. FIG. 3 is an action diagram of a compression load in the refrigerant compressor of FIG. 1. It is a figure which shows each contact state of a main bearing and a main bearing when the main shaft of FIG. 1 inclines in a main bearing, and the correlation of the relational expression materialized in each contact state. It is a graph which shows the setting range of an Example and a comparative example. It is a schematic sectional drawing of the rotary (rotary type) refrigerant compressor which concerns on 2nd Embodiment. It is an expanded sectional view of the B section of the refrigerant compressor of FIG. FIG. 9 is a sectional view taken along the line AA ′ of the refrigerant compressor of FIG. 8. It is a schematic diagram of the refrigerating device which concerns on 3rd Embodiment. It is a schematic sectional drawing of the conventional refrigerant compressor.

Hereinafter, each embodiment will be described with reference to the drawings.
(First embodiment)
[Refrigerant compressor]
FIG. 1 is a schematic cross-sectional view of a reciprocating (reciprocating) refrigerant compressor 100 according to the first embodiment. As shown in FIG. 1, the refrigerant compressor 100 includes a closed container 101, an electric element 106, a compression element 107, and an oil supply pump 120. The closed container 101 is filled with a refrigerant gas (R600a as an example). Refrigerating machine oil 103 (mineral oil as an example) is stored at the bottom of the closed container 101.

The electric element 106 is housed in the closed container 101 and driven by electric power supplied from the outside. The electric element 106 has a stator 104 and a rotor 105. The compression element 107 is housed in the closed container 101, is attached to the refrigerating machine oil 103, is driven by the electric element 106, and compresses the refrigerant gas supplied from the outside. The compression element 107 has a crankshaft 108, a cylinder block 112, a piston pin 115, a connecting member 117, a piston 132, a valve plate 139, and a cylinder head 140.

The crankshaft 108 is made of cast iron as an example. The crankshaft 108 is arranged so as to extend in the vertical direction. The crankshaft 108 has a main shaft 109 and an eccentric shaft 110 which are arranged side by side in the longitudinal direction. The rotor 105 is press-fitted and fixed to the main shaft 109. As an example, the eccentric shaft 110 is arranged above the main shaft 109. The eccentric shaft 110 is arranged eccentrically with respect to the main shaft 109.

As described later, in the refrigerant compressor 100, the main shaft 109 is pivotally supported by the main bearing 111, and the eccentric shaft 110 is pivotally supported by the eccentric bearing 119. An oil supply pump 120 is provided below the crankshaft 108 so that the refrigerating machine oil 103 is supplied.

The cylinder block 112 is made of cast iron as an example. Inside the cylinder block 112, a substantially cylindrical cylinder bore 113 is formed. The cylinder bore 113 extends in the horizontal direction, and one end of the cylinder bore 113 is sealed by a valve plate 139. The cylinder block 112 has a main bearing 111 that supports the main shaft 109.

The piston 132 is reciprocally inserted in the cylinder bore 113. The internal space between the piston 132 and the valve plate 139 in the cylinder bore 113 is a compression chamber 134. A piston pin hole 116 is formed in the piston 132. The piston pin 115 is non-rotatably locked in the piston pin hole 116. The piston pin 115 is formed in a substantially cylindrical shape and is arranged parallel to the eccentric shaft 110.

The eccentric shaft 110 and the piston 132 are connected by a connecting member 117. The connecting member 117 is an aluminum cast product and has an eccentric bearing 119. The connecting member 117 connects the eccentric shaft 110 and the piston 132 via the piston pin 115.

A cylinder head 140 is arranged on the opposite side of the valve plate 139 from the cylinder bore 113. The cylinder head 140 forms a high pressure chamber (not shown) and is fixed to the valve plate 139.

A suction tube (not shown) is fixed to the closed container 101. The suction tube is connected to the low pressure side (not shown) of the refrigeration cycle of the refrigerant compressor 100 and guides the refrigerant gas into the closed container 101. The suction muffler 142 is sandwiched between the valve plate 139 and the cylinder head 140.

When the refrigerant compressor 100 is driven, electric power such as a commercial power supply supplied from the outside is supplied to the electric element 106 via an external inverter drive circuit (not shown). As a result, the electric element 106 is driven by an inverter at a plurality of operating frequencies.

The crankshaft 108 is rotated by the rotor 105 of the electric element 106, and the eccentric shaft 110 moves eccentrically. The connecting member 117 reciprocates the piston 132 in the cylinder bore 113 via the piston pin 115. As a result, the refrigerant gas introduced into the closed casing 101 through the suction tube is sucked into the compression chamber 134 from the suction muffler 142 and compressed in the compression chamber 134.

The refrigerating machine oil 103 is supplied to each sliding part from the oil supply pump 120 as the crankshaft 108 rotates, and lubricates the sliding part. The refrigerator oil 103 also seals between the piston 132 and the cylinder bore 113. Hereinafter, the details of the shaft portion and the bearing portion of the refrigerant compressor 100 will be illustrated.

[Shaft and bearing]
The refrigerant compressor 100 includes a shaft portion that is at least one of the main shaft 109 and the eccentric shaft 110, and a bearing portion that is at least one of the main bearing 111 and the eccentric bearing 119. In at least one of the one axial end and the other axial end of the bearing portion, the diameter of the shaft portion or the bearing portion changes from the outer side in the longitudinal direction of the crankshaft 108 toward the central side. A taper portion is provided to bring the shaft portion and the bearing portion into line contact with each other in a state where the axis of the portion is inclined with respect to the axis of the bearing portion.

Further, in the refrigerant compressor 100, the ratio C / D between the diameter D of the shaft portion and the clearance C between the shaft portion and the bearing portion is 4.0 × 10 ⁻⁴ or more and 3.0 × 10 ⁻³ or less. The taper depth d _B set to a value in the range and corresponding to the distance in the direction perpendicular to the axis of the bearing between the one end and the other end of the taper in the axial direction of the bearing is 2.0 × 10 ^−. It is set to a value of ³ mm or more.

Also, in the refrigerant compressor 100, a pair of taper portions is provided on both axial sides of the bearing portion in one of the shaft portion and the bearing portion. When the taper portion is provided on the shaft portion, the outer diameter of the taper portion changes from one end to the other end in the axial direction of the shaft portion. When the bearing portion is provided with a taper, the inner diameter of the tapered portion changes from one end to the other end in the axial direction of the bearing portion.

In the refrigerant compressor 100, the taper depth d _BU , which is the taper depth d _B of the taper portion on one end side in the axial direction of the bearing portion, and the axial width of the bearing portion of the taper portion on the one end side in the axial direction of the bearing portion. A certain taper width W _BU , a taper depth d _BL that is the taper depth d _B of the taper portion on the other end side in the axial direction of the bearing portion, and an axial direction of the bearing portion of the taper portion on the other end side in the axial direction of the bearing portion. The taper width W _BL, which is the width, the bearing length B of the bearing portion, and the clearance C satisfy the equations 1 and 2.
[Equation 1]
d _BU / W _BU ≤ (C + d _BU + d _BL ) / B
[Equation 2]
d _BL / W _BL ≤ (C + d _BU + d _BL ) / B

Here, (C + d _BU + d _BL ) corresponds to the maximum gap G that is the sum of the clearance C, the taper depth d _BU, and the taper depth d _BL . In other words, the maximum gap G is the sum of the total value and the clearance C of the taper depth d _B of the tapered portion in combination with the corresponding shaft portion and the bearing portion. Hereinafter, (C + d _BU + d _BL ) is also referred to as the maximum gap G.

Next, the refrigerant compressor 100 having such a configuration will be illustrated in detail. FIG. 2 is an enlarged cross-sectional view of the E portion of the refrigerant compressor 100 of FIG. FIG. 3 is a cross-sectional view of the main parts of the refrigerant compressor 100 of FIG. As shown in FIGS. 1 to 3, the main shaft 109 extends in the vertical direction.

In the refrigerant compressor 100, a first sliding surface is formed on the mating surface of the shaft portion and the bearing portion, which is opposite to the surface of the tapered portion at one axial end of the bearing portion. A second sliding surface is formed on the mating surface of the shaft portion and the bearing portion that faces the surface of the tapered portion on the other axial side of the bearing portion.

Further, in the refrigerant compressor 100, at least one of the shaft portion and the bearing portion is provided with a pair of tapered portions on both sides in the axial direction of the bearing portion, and has a small diameter portion having a diameter smaller than the maximum diameter of the tapered portion.

As an example, in the refrigerant compressor 100 of the present embodiment, the main shaft 109 has a first sliding surface 151, a small diameter portion 152, and a second sliding surface 153. The first sliding surface 151 is arranged above the main shaft 109. The second sliding surface 153 is arranged below the main shaft 109. The small diameter portion 152 is arranged between the first sliding surface 151 and the second sliding surface 153.

The small diameter portion 152 has a smaller diameter than the first sliding surface 151. The diameter D _{LO of} the portion of the main shaft 109 on which the second sliding surface 153 is arranged is equal to the diameter D _{UO of} the portion of the main shaft 109 on which the first sliding surface 151 is arranged (see FIG. 5).

The main bearing 111, which supports the main shaft 109, is arranged so that its axis extends in the vertical direction. 170 U of taper parts are provided in the upper end of the inner peripheral surface of the main bearing 111. 170 L of taper parts are provided in the lower end of the inner peripheral surface of the main bearing 111. That is, in the present embodiment, the pair of tapered portions are provided on the bearing portion. The inner diameter of the portion of the main bearing 111 other than where the tapered portions 170U and 170L are provided is constant.

When viewed from a direction perpendicular to the axis of the tapered portions 170U, 170L, the tapered portions 170U, 170L have a linear or continuous curved surface. Although the tapered portion 170U has a linear surface between the inner end 171 and the outer end 172 in the axial direction of the main bearing 111 in FIG. 2, the tapered portion 170L has the same structure. Have.

The tapered portions 170U and 170L are formed on the inner circumferential surface of the main bearing 111 over the entire circumferential direction. The taper depth d _B (d _BU , d _BL ) corresponding to the distance in the direction perpendicular to the axis of the main bearing 111 between the one end 171 and the other end 172 of the tapered portions 170U, 170L in the axial direction of the main bearing 111 is , Here, it is set to a value on the order of μm.

The method of forming the tapered portions 170U and 170L is not limited. The taper portions 170U and 170L of the present embodiment are based on the main bearing 111 using a trial tool composed of a radial needle bearing having an inner diameter of 12 mm, an outer diameter of 16 mm, and a roller diameter of 2 mm, and a rotary shaft having a slight gradient. It is formed by press-fitting while rotating into a bearing to be deformed and deforming the end portion of the bearing.

Here, the clearance C corresponds to the difference between the inner diameter of the bearing portion when there is no tapered portion and the outer diameter of the portion of the shaft portion facing the inner peripheral surface of the bearing portion. When the outer diameter of the shaft portion facing the inner peripheral surface of the bearing portion is different at a plurality of positions, the clearance C is relative to the inner diameter of the bearing portion without the tapered portion and the inner peripheral surface of the bearing portion. It corresponds to the difference from the maximum outer diameter of the shaft portion.

Specifically, as described above, when the diameters D _LO and _DUO of the shaft portion are the same, the clearance C is the inner diameter of the bearing portion when there is no tapered portion, and the sliding surface 151 of the shaft portion. This corresponds to the difference from the outer diameter of the portion where 153 is provided. In this embodiment in other words, the clearance C is, the tapered portion of the main bearing 111 170 U, the inner diameter _{D I} of the portion excluding the 170L, the diameter of the first and second portion sliding surface 151, 153 is provided in the main shaft 109 It is the difference between D _LO and D _UO .

Further, when the diameters D _LO and D _{UO of} the shaft portion are different, the clearance C is the larger of the inner diameter of the main bearing 111 when there is no taper portion and the diameter D _LO or D _UO of the main shaft 109. It can be the difference from the diameter.

As shown in FIGS. 2 and 3, in the present embodiment, as an example, in the cross section of the end portion of the main bearing 111 in the plane including the axis 111c of the main bearing 111, the taper in the direction parallel to the axis 111c of the main bearing 111 is obtained. The taper width W _BU of the portion 170U (in other words, the taper width W _BU which is the axial width of the main bearing 111 of the taper portion 170U on the one axial end side of the main bearing 111) is set to 10 mm, and the taper depth d _BU is It is set to 4.0 × 10 ⁻³ mm.

Further, in the cross section of the end portion of the main bearing 111 in the plane including the axis 111c of the main bearing 111, the taper width W _BL of the taper portion 170L in the direction parallel to the axis 111c of the main bearing 111 (in other words, of the main bearing 111). The taper width W _BL which is the axial width of the main bearing 111 of the tapered portion 170L on the other end side in the axial direction is set to 10 mm, and the taper depth d _BL is set to 4.0 × 10 ⁻³ mm.

The bearing length B of the main bearing 111 is set to 43.5 mm. The inner diameter D _{I of} the portion of the main bearing 111 excluding the tapered portions 170U and 170L is set to 16.026 mm. Each diameter D _O of the portion of the main shaft 109 where the first sliding surface 151 is formed and the portion of the main shaft 109 where the second sliding surface 153 is formed is set to 16.010 mm. The clearance C between the main shaft 109 and the main bearing 111 is set to 1.6 × 10 ⁻² mm.

As a result, both d _BU / w _BU and d _BL / w _BL are set to 4.0 × 10 ⁻⁴ . Further, (C + d _BU + d _BL ) / B is set to 5.5 × 10 ⁻⁴ . That is, d _BU / w _BU and d _BL / w _BL both satisfy the relationship smaller than (C + d _BU + d _BL ) / B, and the ratio C / of the clearance C and the diameter D _{O of the} main shaft 109. D _O is set to 1.0 × 10 ⁻³ .

Here the refrigerant compressor 100, the corresponding shaft portion and the total value of the taper depth d _B of the tapered portion in combination with the bearing portion (where the two tapered portions 170U in combination with the main bearing 111 and main shaft 109, 170L The maximum gap G (= C + d _BU + d _BL ) which is the sum of the total taper depth d _BU + d _BL ) and the clearance C, and the diameter D of the shaft portion (the diameter D _{O of the} main shaft 109 in the above example). The ratio G / D is set to a value of 4.0 × 10 ⁻³ or less.

As described above, the ratio C / D, the taper depth d _B (d _BU , d _BL ) and the ratio G / D are set to values in the above range, respectively, with respect to the diameter D of the shaft portion. The distance between the shaft portion and the bearing portion can be appropriately set, and the tapered portions 170U and 170L having favorable inclined surfaces can be formed. This can prevent local metal contact between the shaft portion and the bearing portion, and promote formation of an oil film between the sliding portions of the shaft portion and the bearing portion. Therefore, the refrigerant compressor 100 having excellent long-term durability, low input and high efficiency can be provided.

Also, in the refrigerant compressor 100, the bearing length B of the bearing portion and the clearance C satisfy the relational expressions of the equations 1 and 2. As a result, the degree of inclination of the tapered portions 170U, 170L is adjusted to an appropriate degree, so that when the shaft portion swings around when the refrigerant compressor 200 is driven, the surfaces of the tapered portions 170U, 170 and The surfaces of the shafts facing each other can be easily aligned with each other (see FIG. 6). Therefore, it is possible to further facilitate the formation of the oil film between the surfaces of the tapered portions 170U and 170 and the surface of the shaft portion facing the tapered portions 170U and 170.

In the refrigerant compressor 100, as an example, the first sliding surface 151 faces the surface of the tapered portion 170U, and the sliding width L ₁ of the first sliding surface 151 is greater than the tapered width W _BU of the tapered portion 170U. And the second sliding surface 153 faces the surface of the tapered portion 170L, and the sliding width L ₂ of the second sliding surface 153 is smaller than the tapered width W _BL of the tapered portion 170L. ing. Thereby, the viscous resistance between the shaft portion and the bearing portion is effectively reduced.

Further, in the refrigerant compressor 100, the ratio G / D is set to a value of 4.0 × 10 ⁻³ or less. As a result, the ratio between the maximum gap G and the diameter D of the shaft portion can be optimized, so that it is possible to prevent the inclination gradient in the bearing portion of the crankshaft 108 from becoming excessive and the partial contact described later to increase. Therefore, for example, it can be prevented that the tip end of the piston 132 is abraded due to one-sided contact, the amount of refrigerant leak from the abraded portion is increased, and the refrigerating capacity is lowered.

Further, the shaft portion of the refrigerant compressor 100 has a film formed on the surface portion that slides on the bearing portion. This coating has a hardness equal to or higher than the hardness of the opposing surfaces of the bearing portion. In the present embodiment, at least one (both here) of the main shaft 109 and the eccentric shaft 110 has this coating.

The type of coating is not limited, but examples include oxide coatings. Examples of the oxide film include a film of iron oxide. The iron oxide film is chemically very stable and has a high hardness as compared with, for example, a phosphate film. By forming the oxide film, it is possible to effectively prevent generation of wear powder and adhesion of the wear powder to the film. Therefore, an increase in the amount of wear of the oxide film itself can be effectively avoided, and high wear resistance can be imparted to the film.

Like the oxide film, the film may be harder than the mating material. In addition, if the base material of the shaft portion where the coating is formed is an iron-based material, the coating is formed not only by general quenching, but by impregnating the surface of the shaft portion with carbon, nitrogen, etc. May be. Further, the film may be formed by an oxidation treatment with water vapor or an oxidation treatment of immersing the material in an aqueous solution of sodium hydroxide or the like.

Further, the film is not limited to the compound layer formed by the above-mentioned oxidation, carburization, nitriding, oxidation treatment, etc., for example, cold working, work hardening, solid solution strengthening, precipitation strengthening, dispersion strengthening, grain refinement, etc. Any of the above may be a strength enhancing layer in which the base material is strengthened by suppressing the slip motion of dislocations. Further, the coating may be a treated layer formed by any coating method such as plating, thermal spraying, PVD and CVD.

[Confirmation test]
The refrigerant compressor 100 of the first embodiment was manufactured as an example. A refrigerant compressor similar to the refrigerant compressor 100 except that the tapered portions 170U and 170L are not provided was manufactured as a conventional example. The performance of these refrigerant compressors was evaluated when they were operated at a low speed by inverter drive (operating frequency of 17 Hz).

4A is a characteristic diagram showing the input ratio between the embodiment of the refrigerant compressor of FIG. 1 and the conventional example. FIG. 4B is a characteristic diagram showing the coefficient of performance (COP) ratio of the embodiment of the refrigerant compressor of FIG. 1 and the conventional example.

The coefficient of performance is a coefficient used as a guideline (index) of energy consumption efficiency of refrigeration equipment, and is a value obtained by dividing the refrigerating capacity (W) by the applied input (W). FIG. 4A shows the ratio (input ratio) when the applied input value of the conventional example is 100. FIG. 4B shows each ratio (COP ratio) when the COP value of the conventional example is 100.

From the results shown in FIGS. 4 (a) and 4 (b), in the embodiment, the taper portions 170U and 170L are provided as compared with the comparative example, so that the input becomes lower than that in the conventional example and the COP is reduced. It was confirmed to be high.

Here, FIG. 5 is an action diagram of the compression load in the refrigerant compressor 100 of FIG. 1. In FIG. 5, the compression load acting on the refrigerant compressor 100 is schematically shown. The confirmation test results of the example and the conventional example will be considered as follows with reference to FIG.

In a reciprocating refrigerant compressor such as the refrigerant compressor 100, generally, a compression load P generated in the cylinder axis direction of the cylinder bore 113 in a compression chamber 134 formed between the cylinder bore 113 and the piston 132. The pressure inside the closed container 101 is lower than that of The compression load P acts on the eccentric shaft 110, while the main shaft 109 is cantilevered by a single main bearing 111. Therefore, when the refrigerant compressor is driven, the crankshaft 108 is affected by the compression load P, as shown in the document of Ito et al. (Annual Meeting of the Japan Society of Mechanical Engineers Vol.5-1 (2005) P.143). Therefore, the main bearing 111 swings in an inclined state.

Accordingly, the component force P1 of the compressive load P acts on the portion of the main shaft 109 corresponding to the upper end portion of the main bearing 111, and the component force P2 of the compressive load P corresponds to the main shaft 109 corresponding to the lower end portion of the main bearing 111. By acting on the part of, so-called partial contact occurs. In the conventional refrigerant compressor, when the main shaft 109 tilts in the main bearing 111, local contact between the main shaft 109 and the main bearing 111 may occur to increase the surface pressure. When the operation becomes slower, the thickness of the oil film formed between the main shaft 109 and the main bearing 111 becomes thinner or the oil film is cut off. As a result, solid contact between the main shaft 109 and the main bearing 111 occurs and sliding loss increases.

On the other hand, in the present embodiment (example), by providing the main bearing 111 with the tapered portions 170U and 170L, even if the main shaft 109 is tilted in the main bearing 111, the main bearing 111 is inclined from the direction perpendicular to the axis of the main bearing 111. As viewed, the main shaft 109 and the main bearing 111 are arranged such that the facing surfaces thereof are along each other. As a result, local metal contact between the main shaft 109 and the main bearing 111 is prevented.

Further, in the present embodiment (example), the maximum gap G (= C + d _BU + d _BL ) which is the total value of the clearance C, the taper depth d _BU, and the taper depth d _BL is secured relatively large. It is presumed that the viscous resistance of the refrigerating machine oil 103 was thereby reduced, the sliding loss was significantly reduced, and the input of the refrigerant compressor was effectively lowered.

From the above results, by providing the tapered portion on the bearing portion of the refrigerant compressor, it is possible to prevent local metal contact between the bearing portion and the shaft portion to improve the durability and improve the performance of the refrigerant compressor. I found out that

[Evaluation test]
Next, based on the results of the above confirmation test, a performance evaluation test and a reliability evaluation test of the refrigerant compressor were performed to clarify each numerical range capable of improving the performance of the refrigerant compressor. In the performance evaluation test, the clearance C between the main shaft and the main bearing, the bearing length B, the diameter D _{O of} the main shaft, the ratio C / D _O with the clearance C, the taper depths d _BU and d _{BL of} the taper portions 170U and 170L, and The taper widths W _BU and W _BL were used as parameters. In the performance evaluation test, the refrigerant compressor was driven at a low speed by an inverter drive (operating frequency of 17 Hz).

In the reliability evaluation test, after operating the refrigerant compressor for 160 hours in the high temperature and high load intermittent operation mode, disassemble the refrigerant compressor and measure the wear of sliding parts (crankshaft, piston, etc.). Was evaluated by.

Hereinafter, the taper width W _BU and the taper depth d _BU of the taper portion 170U, the taper width W _BL and the taper depth d _{BL of} the taper portion 170L, the bearing length B of the main bearing 111, the main shaft 109 and the main bearing. In the graph plotting the relationship between the clearance C of 111 (see FIG. 7), the range that satisfies the above-described relational expressions of Formula 1 and Formula 2 is referred to as area A1, and the range that satisfies the relational formulas of Formula 3 and Formula 4 below. Is referred to as area A2.

[Equation 3]
d _BU / W _BU > (C + d _BU + d _BL ) / B
[Formula 4]
d _BL / W _BL > (C + d _BU + d _BL ) / B

Further, in each of these tests, the clearance C between the main shaft 109 and the main bearing 111 was set to 1.6 × 10 ⁻² mm, and the bearing length B of the main bearing 111 was set to 43.5 mm. FIG. 6 is a diagram showing a correlation between each contact state between the main shaft 109 and the main bearing 111 when the main shaft 109 in FIG. 1 is inclined in the main bearing 111, and a relational expression established in each contact state. FIG. 7 is a graph showing the setting ranges of Examples 1 and 2 and Comparative Examples 1 and 2. Table 1 shows the evaluations in the performance evaluation test and the reliability evaluation test of Examples 1 and 2 and Comparative Examples 1 and 2.

The lower horizontal axis of the graph in FIG. 7 shows the taper depths d _BU and d _BL , and the upper horizontal axis shows the ratio (C + d _BU + d _BL ) / D of the maximum gap G and the diameter D of the shaft portion. The vertical axis of FIG. 7 shows the taper widths W _BU and W _BL . The solid line shown in FIG. 7 indicates a position that satisfies the relational expressions of the following Expressions 5 and 6.
[Equation 5]
d _BU / w _BU = (C + d _BU + d _BL ) / B
[Equation 6]
_dBL / _wBL = (C + _dBU + _dBL ) / B

In the test shown in FIG. 7, the taper depths d _BU and d _BL are 2.0 × 10 ⁻³ mm or more, and the ratio (C + d _BU + d _BL ) / D of the maximum gap G and the diameter D of the shaft portion is 4. The refrigerant compressor 100 set to satisfy the relational expressions 1 and 2 in the region of 0.0 × 10 ⁻³ or less was set as Example 1. On the other hand, the taper depths d _BU and d _BL are 2.0 × 10 ⁻³ mm or more, and the ratio (C + d _BU + d _BL ) / D of the maximum gap G to the diameter D of the shaft portion is 4.0 × 10 ^{−. The} refrigerant compressor set so as to satisfy the relational expressions of Formulas 3 and 4 in the region of ³ or less was set as Example 2.

Further, Comparative Example 1 is a refrigerant compressor in which the taper depths d _BU and d _BL are set to values less than 2.0 × 10 ⁻³ mm. Further, Comparative Example 2 was a refrigerant compressor in which the ratio (C + d _BU + d _BL ) / D of the maximum gap G and the diameter D of the shaft portion was set to a value exceeding 4.0 × 10 ⁻³ .

Also, the shafts of Examples 1 and 2 and Comparative Examples 1 and 2 were coated with a film on the surface that slides on the bearing. As this coating, a manganese phosphate film having a hardness lower than that of the mating main bearing or an iron oxide film having a hardness higher than that of the mating main bearing was formed.

When performing the evaluation shown in Table 1, the evaluation was performed based on the performance of the conventional refrigerant compressor without the tapered portion and the wear result in the reliability test. “A” in Table 1 shows that the characteristics were significantly improved as compared with the conventional example, that is, the compressor performance was improved and the wear of the shaft portion and the bearing portion was most alleviated. “B” is the second highest evaluation after “A”, and indicates that the characteristics are slightly higher than those of the conventional refrigerant compressor. "C" is the second highest evaluation after "B" and indicates that no improvement in characteristics was observed as compared with the conventional refrigerant compressor.

As shown in FIG. 7 and Table 1, it was found that in Examples 1 and 2, both performance and reliability were improved as compared with Comparative Examples 1 and 2. Example 1 has higher performance and reliability than Example 2. Particularly, when a film having a hardness higher than that of the mating main bearing material is formed as the film of the shaft portion, excellent compressor performance is obtained. It was found that the wear of the shaft portion and the bearing portion was highly mitigated and the reliability was further improved.

On the other hand, in Comparative Example 1 in which the taper depths d _BU and d _BL are set to values less than 2.0 × 10 ⁻³ mm, the performance is not improved as compared with the conventional example regardless of the areas A1 and A2. I understood. As a cause for this, it is considered that in Comparative Example 1, for example, the taper depth of the taper portion was too shallow, so that the effect due to the difference in shape from the taper portions of Examples 1 and 2 could not be obtained.

Further, in Comparative Example 2 in which the ratio (C + d _BU + d _BL ) / D is set to a value exceeding 4.0 × 10 ⁻³ , the performance is not improved as compared with the conventional example regardless of the areas A1 and A2. I understood. As a cause of this, for example, it is considered that the inclination gradient in the bearing portion of the crankshaft 108 becomes excessively large, and one-sided contact becomes apparent. That is, in Comparative Example 2, it was not possible to confirm the improvement in performance because the tip of the piston 132 was abraded due to the manifestation of this one-sided contact, the amount of refrigerant leaked from the abraded portion was increased, and the refrigerating capacity was decreased. Conceivable.

Also, in a compressor reliability test conducted separately, in Comparative Example 2, it was confirmed that the end portion on the tip side of the piston was significantly worn, which is thought to be due to one-sided contact, and this consideration is supported. ing.

In the above test, the clearance C between the main shaft 109 and the main bearing 111 is set to 1.6 × 10 ⁻² mm, and the bearing length B of the main bearing 111 is set to 43.5 mm. It has been found that the same effect can be obtained when the ratio C / D is set to a value in the range of 4.0 × 10 ⁻⁴ or more and 3.0 × 10 ⁻³ or less.

The diameter D _{O of the} main shaft 109 can be set as appropriate, but can be set to a value in the range of 10 mm or more and 28 mm or less, for example. For example, the clearance C, the taper depths d _BU , d _BL , and the taper are adjusted so that the ratios C / D and (C + d _BU + d _BL ) / D are in the appropriate ranges in accordance with the set diameter D of the shaft. It is desirable to set the widths W _BU and W _BL .

In the refrigerant compressor 100 of the present embodiment, the tapered portions 170U and 170L are provided on the inner peripheral surface of the main bearing 111, but the same effect can be obtained even if the outer peripheral surface of the main shaft 109 is provided with the tapered portions. Be done. Further, the eccentric bearing 119 may be provided with a taper portion on the inner peripheral surface thereof, or the eccentric shaft 110 may be provided with a taper portion on the outer peripheral surface thereof. In these cases, in the combination of the eccentric shaft 110 and the eccentric bearing 119, the ratio C / D, the taper depth, and the ratio G / D are set to be the same as the above-described combination of the main shaft 109 and the main bearing 111. Even with such a configuration, similarly to the present embodiment, it is possible to contribute to the performance and reliability improvement of the refrigerant compressor.

Further, in the present embodiment, the effect that the performance is improved when the refrigerant compressor 100 is operated at a low speed (operating frequency of 17 Hz as an example) has been described. However, when operating at a speed of commercial speed or at a higher speed. The same effect can be obtained even during high speed operation due to.

Also, the type of the refrigerant compressor is not limited to the reciprocating type (reciprocating type), and other types such as a rotary type and a scroll type may be used. That is, in a refrigerant compressor of a rotary type or a scroll type, even if a taper portion is applied to a sliding portion (so-called journal bearing sliding portion) composed of the outer peripheral surface of the shaft and the inner peripheral surface of the bearing, the same result is obtained. The effect of improving performance and reliability can be obtained. Hereinafter, other embodiments will be described focusing on differences from the first embodiment.

(Second embodiment)
FIG. 8 is a schematic sectional view of a rotary (rotary) refrigerant compressor 200 according to the second embodiment. FIG. 9 is an enlarged cross-sectional view of part B of the refrigerant compressor 200 of FIG. FIG. 9 corresponds to an enlarged cross-sectional view of a portion B (lower side of the main bearing 209) surrounded by a broken line circular frame in FIG. FIG. 10 is a cross-sectional view of the refrigerant compressor 200 of FIG. 8 taken along the line AA ′.

As shown in FIGS. 8 to 10, the refrigerant compressor 200 includes a closed container 201, an electric element 202, and a compression element 203. Refrigerating machine oil 220 is stored at the bottom of the closed container 101. The electric element 202 and the compression element 203 are housed in the closed container 201. The electric element 202 has a stator 202a and a rotor 202b. The compression element 203 has a crankshaft 208, a main bearing 209, an auxiliary bearing 211, a cylinder 210, and a roller 213.

The crankshaft 208 extends in the vertical direction, and has a main shaft 206 and an eccentric shaft 212 arranged in the middle of the main shaft 206. The main shaft 206 is pivotally supported by the main bearing 209 above the eccentric shaft 212, and is pivotally supported by the sub bearing 211 below the eccentric shaft 212. The rotor 202b of the electric element 202 is fixed to the main shaft 206. The outer circumference of the rotor 202b is surrounded by the stator 202a.

The eccentric shaft 212 is arranged inside the cylinder 210 penetrating in the vertical direction. The roller 213 is formed in a tubular shape and is arranged so that its axis extends vertically. Inside the cylinder 210, the main shaft 206 and the eccentric shaft 212 are inserted into a roller 213. The eccentric shaft 212 is supported on the inner peripheral surface of the cylinder 210 via a roller 213. In the present embodiment, the roller 213 corresponds to the eccentric bearing of the eccentric shaft 212. When the refrigerant compressor 200 is driven, the roller 213 makes a planetary motion around the main shaft 206 of the crankshaft 208.

The cylinder 210 is provided with a through groove 222 extending in the horizontal direction. A shaft-shaped vane 214 is inserted into the through groove 222. One end (tip) in the longitudinal direction of the vane 214 is pressed against the peripheral surface 231 of the roller 213 by the spring 215 and the back pressure (discharge pressure). As a result, the space between the cylinder 210 and the roller 213 is divided into a suction chamber 216 for sucking the refrigerant gas from the outside and a compression chamber 217 for compressing the refrigerant gas.

The cylinder 210 is further provided with a suction hole 205. One end of the suction pipe 204 is inserted into the suction hole 205. The refrigerant compressor 200 is connected to an accumulator (not shown) via a suction pipe 204. A discharge notch 219 is provided on the inner peripheral surface of the cylinder 210.

When the refrigerant compressor 200 is driven, the electric element 202 causes the crankshaft 208 to rotate around the main shaft 206, causing the roller 213 to make a planetary motion (in FIG. 10, rotate left). As a result, the refrigerant gas is sucked into the suction chamber 216 from the outside through the suction pipe 204 and the suction hole 205. The refrigerant gas is compressed by increasing the internal pressure of the compression chamber 217, and is discharged into the closed container 201 through the discharge notch 219 through a discharge hole (not shown).

Here, one end in the longitudinal direction of the vane 214 that partitions the suction chamber 216 and the compression chamber 217 is pressed against the peripheral surface 231 of the roller 213 by the spring 215 and the back pressure. As a result, the vane 214 moves while sliding at the contact point with the peripheral surface 231 of the roller 213. Due to this luck, the crankshaft 208 is subjected to pressure from a direction perpendicular to the axis of the main shaft 206, and thus is bent. As a result, the crankshaft 208 rotates so as to swing between the clearances between the main bearing 209 and the auxiliary bearing 211.

Due to this whirling, the crankshaft 208 causes the upper end of the main bearing 209 (the end on the electric element 202 side in FIG. 8), the lower end of the main bearing 209 (the end on the roller 213 side in FIG. 8), and the auxiliary bearing 211. Of at least one of the upper end (the end on the roller 213 side in FIG. 8) and the lower end of the auxiliary bearing 211 (the end on the oil filler 221 side provided at the lower end of the crankshaft 208 in FIG. 8) of the auxiliary bearing 211. There may be a hit. Due to this one-sided contact, scratches may be generated on the sliding surface, or adhesive wear may occur in which the sliding surface is cut and worn by minute abrasion powder.

Therefore, in the refrigerant compressor 200, the tapered portion 270U is provided at the upper end of the main bearing 209 that pivotally supports the crankshaft 208, and the tapered portion 270L is provided at the lower end of the main bearing 209. Further, a tapered portion 280U is provided on the upper end of the sub bearing 211, and a tapered portion 280L is provided on the lower end of the sub bearing 211. The taper portions 270U and 280U correspond to the taper portion 170U, and the taper portions 270L and 280L correspond to the taper portion 170L. Note that, in FIG. 9, only the tapered portion 270L is shown among the respective tapered portions.

The tapered portions 270U and 270L are formed on the inner peripheral surface of the main bearing 209 over the entire circumferential direction. The taper depth d _B (d _BU , d _BL ) corresponding to the distance in the direction perpendicular to the axis of the main bearing 209 between the one end 271 and the other end 272 of the tapered portions 270U, 270L in the axial direction of the main bearing 209 is , Here, it is set to a value on the order of μm.

Further, as shown in FIGS. 8 and 9, the ratio C / D between the diameter D of the crankshaft 208 (main shaft 206) and the clearance C between the crankshaft 208 (main shaft 206) and the bearing portion (main bearing 209) is 4 It is set to a value in the range of 0.0 × 10 ^{−4 to} 3.0 × 10 ⁻³ . Further, the ratio G / D in the corresponding combination of the shaft portion and the bearing portion (here, the combination of the main shaft 206 and the main bearing 209) is set to a value of 4.0 × 10 ⁻³ or less.

Although not shown, the ratio C / D between the diameter D of the crankshaft 208 (main shaft 206) and the clearance C between the crankshaft 208 (main shaft 206) and the bearing portion (secondary bearing 211) is also 4.0 × 10 ^−4. The value is set in the range of 3.0 × 10 ⁻³ or less.

Further, at least one (both here) of the taper depth d _BU (not shown) of the taper portions 270U and 280U and the taper depth d _BL of the taper portions 270L and 280L is 2.0 × 10 ^−. It is set to a value in the range of ³ mm or more. Further, the crankshaft 208 has a film formed on the surface portion that slides with respect to the main bearing 209 and the auxiliary bearing 211. This film is similar to the film of the first embodiment.

By such setting, even if the crankshaft 208 swings and the above-mentioned one-sided contact occurs, the facing surface between the main shaft 206 and the main bearing 209 is seen from the direction perpendicular to the axis of the crankshaft 208. , And the respective facing surfaces of the main shaft 206 and the sub bearing 211 are arranged so as to be along each other. This prevents local metal contact between the main shaft 206 and the main bearing 209 and between the main shaft 206 and the sub bearing 211. Therefore, the refrigerant compressor 200 has good friction and wear characteristics and high performance and reliability.

The tapered portion 270L shown in FIG. 9 is formed in a curved shape having a continuous curved surface when viewed from a direction perpendicular to the axis thereof, but is formed so as to have a linear surface. May be. Further, when a plurality of tapered portions are provided, tapered portions having different shapes may be provided. Further, the refrigerant compressor 200 has four taper portions 270U, 270L, 280U, 280L, but it suffices to have at least one taper portion among them.

Also, the target on which the above-mentioned film is formed is not limited to the crankshaft 208. The above-described film may be provided on a sliding portion of any of the components of the refrigerant compressor and the refrigerating apparatus using the same (for example, units such as parts and devices, and units such as pumps and motors). Next, a configuration of a refrigeration system using the refrigerant compressors 100 and 200 will be exemplified.

(Third Embodiment)
FIG. 11 is a schematic diagram of the refrigeration apparatus 300 according to the third embodiment. The outline of the basic configuration of the refrigerating apparatus 300 will be described below. As shown in FIG. 11, the refrigeration system 300 includes a main body 301, a partition wall 307, and a refrigerant circuit 309.

The main body 301 has a heat insulating box body having an opening communicating with the inside thereof, and a door for opening and closing the opening of the box body. Further, the main body 301 has a storage space 303 in which articles are stored, and a machine room 305 in which a refrigerant circuit 309 that cools the storage space 303 is arranged. The storage space 303 and the machine room 305 are partitioned by a partition wall 307. A blower (not shown) is arranged in the storage space 303. In FIG. 11, a part of the box body is cut away to show the inside of the main body 301.

The refrigerant circuit 309 includes one of the refrigerant compressors 100 and 200, a radiator 313, a pressure reducing device 315, and a heat absorber 317. Any of the refrigerant compressors 100 and 200, the radiator 313, the pressure reducing device 315, and the heat absorber 317 are connected in an annular shape by piping.

The radiator 313 radiates heat from the refrigerant. The decompression device 315 decompresses the refrigerant. The heat absorber 317 absorbs heat of the refrigerant. The heat absorber 317 is disposed in the storage space 303 to generate cooling heat. As shown by the arrow in FIG. 11, the cooling heat of the heat absorber 317 is circulated in the storage space 303 by the blower. Thereby, the air in the storage space 303 is agitated and the inside of the storage space 303 is cooled.

The refrigerating apparatus 300 having the above-described configuration can obtain high wear resistance between the shaft portion and the bearing portion and promote the formation of an oil film between the shaft portion and the bearing portion in either the refrigerant compressor 100 or 200. As a result, local metal contact between the shaft portion and the bearing portion can be prevented, and high reliability and compressor performance can be obtained. Accordingly, in the refrigeration system 300, by including the refrigerant compressors 100 and 200, power consumption can be reduced, energy saving can be realized, and long-term reliability can be improved.

The present invention is not limited to each embodiment, and its configuration can be changed, added, or deleted without departing from the spirit of the present invention. The respective embodiments may be arbitrarily combined with each other, and for example, a part of the configuration in one embodiment may be applied to another embodiment. The scope of the present invention is defined by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

INDUSTRIAL APPLICABILITY As described above, the present invention provides a refrigerant compressor capable of achieving high efficiency while preventing deterioration of durability and reliability by preventing abrasion of sliding parts, and a refrigeration apparatus using the same. It has an excellent effect that can be provided. Therefore, it is beneficial to widely apply the present invention to a refrigerant compressor and a refrigerating apparatus using the same, which can exert the significance of this effect.

100, 200 Refrigerant compressor 101, 201 Airtight container 103, 220 Refrigerating machine oil 106, 202 Electric element 107, 203 Compression element 108, 208 Crank shaft 109, 206 Main shaft (shaft part)
110,212 Eccentric shaft (shaft part)
111,209 Main bearing (bearing part)
111c Main bearing axis 119 Eccentric bearing (bearing part)
151 First Sliding Surface 152 Small Diameter Section 153 Second Sliding Surface 170U, 170L, 270U, 270L, 280U, 280L Tapered Part 211 Secondary Bearing (Bearing Part)
300 Refrigerator 309 Refrigerant circuit 313 Radiator 315 Pressure reducer 317 Heat absorber B Bearing width C Clearance D Shaft diameter D _O Main shaft diameter D _I Main bearing diameter (inner diameter)
d _B , d _BU , d _BL taper depth L ₁ sliding width of first sliding surface L ₂ sliding width of second sliding surface w _BU , w _BL taper width

Claims (8)

1. A closed container in which refrigerating machine oil is stored,
   An electric element housed in the closed container and driven by electric power supplied from the outside,
   And a compression element that is housed in the closed container and is attached to the refrigerating machine oil, is driven by the electric element, and compresses a refrigerant gas supplied from the outside,
   The compression element is a crankshaft having a main shaft and an eccentric shaft arranged side by side in the longitudinal direction,
   A main bearing for supporting the main shaft,
   An eccentric bearing that supports the eccentric shaft,
   At least one of a shaft portion that is at least one of the main shaft and the eccentric shaft and a bearing portion that is at least one of the main bearing and the eccentric bearing has at least one end side and the other end side in the axial direction of the bearing portion. On the other hand, as the diameter of the crankshaft changes from the outside in the longitudinal direction toward the center, the axis of the shaft part is inclined with respect to the axis of the bearing part, and the shaft part and the bearing part are Is provided with a taper that makes line contact with
   The ratio C / D of the diameter D of the shaft portion and the clearance C between the shaft portion and the bearing portion is set to a value in the range of 4.0 × 10 ⁻⁴ or more and 3.0 × 10 ⁻³ or less. Is set,
   A taper depth d _B corresponding to a distance between one end and the other end of the tapered portion in the axial direction of the bearing portion in a direction perpendicular to the axis of the bearing portion is 2.0 × 10 ⁻³ mm or more. Is set to the value
   The ratio G / D of the maximum gap G is the sum of the total value and the clearance C of the taper depth d _B of the tapered portion and corresponding one of the shaft portion in combination with the bearing portion, the diameter D of the shaft portion Is a refrigerant compressor having a value of 4.0 × 10 ⁻³ or less.
2. A pair of the taper portions are provided on both sides in the axial direction of the bearing portion in one of the shaft portion and the bearing portion,
   A taper depth d _BU that is the taper depth d _B of the tapered portion on one axial side end of the bearing portion and an axial width of the bearing portion of the tapered portion on one axial side end of the bearing portion. Taper width W _BU ,
   A taper depth d _BL that is the taper depth d _B of the tapered portion on the other end side in the axial direction of the bearing portion, and an axial width of the bearing portion of the tapered portion on the other end side in the axial direction of the bearing portion. And the taper width W _BL is
   The refrigerant compressor according to claim 1, wherein the bearing length B of the bearing portion and the clearance C satisfy Formula 1 and Formula 2.
   [Equation 1]
   d _BU / W _BU ≤ (C + d _BU + d _BL ) / B
   [Equation 2]
   d _BL / W _BL ≤ (C + d _BU + d _BL ) / B
3. Of the shaft portion and the bearing portion, a first sliding surface is formed on a mating surface opposite to the surface of the tapered portion on the one axial end side of the bearing portion,
   Of the shaft portion and the bearing portion, a second sliding surface is formed on a mating surface opposite to the surface of the tapered portion on the other axial side of the bearing portion,
   The sliding width L ₁ of the _first sliding surface with respect to the surface of the tapered portion is smaller than the tapered width W _{BU when} viewed from a direction perpendicular to the axis of the mating side, and the second sliding surface The refrigerant compressor according to claim 2, wherein a sliding width L ₂ of the taper with respect to the surface of the tapered portion is smaller than the taper width W _BL .
4. At least one of the shaft portion and the bearing portion is provided with a pair of the tapered portions on both sides in the axial direction of the bearing portion, and has a small diameter portion having a diameter smaller than a maximum diameter of the tapered portion. The refrigerant compressor according to any one of 3 above.
5. The refrigerant compressor according to any one of claims 1 to 4, wherein the tapered portion has a linear or continuous curved surface when viewed in a direction perpendicular to an axis of the tapered portion.
6. The shaft portion has a film formed on a portion of the surface that slides with respect to the bearing portion, and the film has a hardness equal to or higher than the hardness of the opposing surfaces of the bearing portion. The refrigerant compressor according to any one of claims 1 to 5, wherein:
7. The refrigerant compressor according to any one of claims 1 to 6, wherein the electric element is driven by an inverter at a plurality of operating frequencies.
8. A refrigerant circuit in which the refrigerant compressor according to any one of claims 1 to 7, a radiator that dissipates the refrigerant, a decompression device that decompresses the refrigerant, and a heat absorber that absorbs the refrigerant are annularly connected by piping. A refrigeration system comprising:

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