CN112352102B

CN112352102B - Sealed refrigeration compressor and refrigerating and freezing device using same

Info

Publication number: CN112352102B
Application number: CN201980043911.3A
Authority: CN
Inventors: 林宽人; 川端淳太; 井出照正; 明石浩业; 权藤政信; 八木章夫
Original assignee: Panasonic Appliances Refrigeration Devices Singapore Pte Ltd
Current assignee: Panasonic Appliances Refrigeration Devices Singapore Pte Ltd
Priority date: 2018-06-27
Filing date: 2019-06-25
Publication date: 2024-02-23
Anticipated expiration: 2039-06-25
Also published as: JP7064562B2; CN112352102A; EP3816441A1; WO2020004382A1; EP3816441A4; JPWO2020004382A1; JP2021073404A; US20210123426A1

Abstract

The sealed refrigeration compressor (100) is stored in a sealed container (101) and has a kinematic viscosity of 1-9mm at 40 DEG C ² Lubricating oil (103) in the range of/S, said lubricating oil (103) comprising sulfur or a sulfur-containing compound as a sliding modifier. A compression element (107) includes a crankshaft (108) as a shaft portion. In the case where the sliding surface of the main shaft (109) is a single sliding surface, the length of the single sliding surface in the axial direction is a single sliding length L, or in the case where the sliding surface is divided into multiple sliding surfaces, the smallest axial length among the multiple sliding surfaces is regarded as a single sliding length L, and the ratio L/D between the single sliding length L and the outer diameter D of the main shaft (109) is 0.51 or less. Further, when the sum of the lengths of the multiple sliding surfaces in the axial direction is the total sliding length Lt, the ratio Lt/D between the total sliding length Lt and the outer diameter D may be 1.26 or less than 1.26.

Description

Sealed refrigeration compressor and refrigerating and freezing device using same

Technical Field

The present invention relates to a sealed refrigeration compressor used in, for example, a refrigerator or an air conditioner, and also relates to a refrigerating and freezing apparatus using the sealed refrigeration compressor.

Background

In recent years, efficient hermetic refrigeration compressors have been developed that reduce the use of fossil fuels from a global environmental point of view. For example, in order to achieve high efficiency, it has been proposed to form various thin films on the sliding surface of a sliding member (included in a refrigeration compressor) and to use lubricating oil having low viscosity.

The hermetic refrigeration compressor includes a hermetic container having lubricating oil stored therein. The sealed container also houses the electrical components and the compression components. The compression element includes a sliding member (e.g., a crankshaft, a piston, and a connecting rod as a coupler). The main shaft and the main bearing of the crankshaft, the piston and the hole, the piston pin and the connecting rod, the eccentric shaft and the connecting rod of the crankshaft, and the like form sliding parts with each other.

For example, patent document 1 discloses a reciprocating compressor (hermetic refrigeration compressor) using a lubricating oil of low viscosity. The reciprocating compressor is constructed such that in the sliding member, the piston and the connecting rod are both made of an iron sintered material and are vapor-treated, and then a vapor layer is removed from the surface of the piston by cutting, and the connecting rod is subjected to nitriding treatment after being vapor-treated. In patent document 1, the lubricating oil used in the reciprocating compressor thus structured has a thickness of 3mm at 40 ℃ ² S to 10mm ² Kinematic viscosity in the range of/S.

If the lubricating oil has a low viscosity, an oil film is not easily formed. In this regard, in the hermetic refrigeration compressor disclosed in patent document 1, the surface of the sliding member forming the sliding portion is subjected to special treatment so that even if a lubricating oil having a low viscosity is used, wear or seizing (seizing) of the piston and the connecting rod will be prevented.

List of references

Patent literature

Patent document 1: japanese laid-open patent application publication No.: no.2011-021530

Disclosure of Invention

Technical problem

Incidentally, a crankshaft included in the hermetic refrigeration compressor constitutes a shaft portion of a compression element driven by an electric element, and the shaft portion is rotatably pivotally supported by a bearing portion. Further improved efficiency can be obtained by reducing the sliding area of each of the shaft portion and the bearing portion (pivot support portion). However, the reduction of the sliding region results in a reduction of wear resistance.

The above reciprocating compressor (hermetic refrigeration compressor) disclosed in patent document 1 uses a low-viscosity lubricating oil having a kinematic viscosity at 40 ℃ of 3mm ² S to 10mm ² In the range of/S. However, the wear resistance to be improved in patent document 1 is that of a piston and a connecting rod, and unlike a crankshaft, the piston and the connecting rod are not pivotally supported by a bearing portion. Therefore, in the case of improving the wear resistance of the piston and the connecting rod, unlike the case of the crankshaft, the sliding region of the pivot support portion will not be reduced in order to achieve high efficiency.

The present invention has been made to solve the above-described problems. An object of the present invention is to provide a sealed refrigeration compressor capable of realizing high reliability of a shaft portion pivotally supported by a bearing portion even if lubricating oil having low viscosity is used.

Solution to the problem

In order to solve the above problems, a hermetic refrigeration compressor according to the present invention comprises a hermetic container in which a kinematic viscosity at 40 ℃ of 1mm is stored ² S to 9mm ² Lubricating oil in the range of/S, the sealed container containing an electrical component and a compression component driven by the electrical component and configured to compress a refrigerant. The compression element includes: a shaft portion which is a crankshaft including a main shaft and an eccentric shaft; and a bearing portion pivotally supporting the shaft portion, the bearing portion including a main bearing pivotally supporting the main shaft and an eccentric bearing pivotally supporting the eccentric shaft. The main shaft comprises a sliding surface sliding on the main bearing, which sliding surface is a single sliding surface or divided into multiple sliding surfaces. In the case where the sliding surface is the single sliding surface, the length of the single sliding surface in the axial direction is a single slide A moving length L, and in the case where the sliding surface is divided into the multiple sliding surfaces, a length of one of the sliding surfaces (one sliding surface having a minimum length in an axial direction among the multiple sliding surfaces) in the axial direction is a single sliding length L, and a ratio L/D of the single sliding length L to an outer diameter D of the main shaft is less than or equal to 0.51. Lubricating oils contain a slip modifier which is sulfur or a sulfur-containing compound.

According to the above configuration, the lubricating oil is a low-viscosity oil; the ratio L/D of the single sliding length L to the outer diameter D is less than or equal to 0.51 regardless of whether the sliding surface of the main shaft is a single sliding surface or a multiple sliding surface; and the lubricating oil contains a sulfur-based sliding modifier. Because of these features, even if the lubricating oil is a low-viscosity oil and the sliding region is reduced so that the ratio L/D is less than or equal to 0.51, good wear resistance of the sliding portion can be achieved by the sulfur-based sliding modifier. Therefore, a sealed refrigeration compressor can be obtained that can achieve high reliability of the shaft portion pivotally supported by the bearing portion even if lubricating oil having a reduced viscosity is used.

A refrigeration and freezer according to the present invention includes a refrigerant circuit including: the hermetic refrigeration compressor constructed as above; a heat sink; a pressure reducer; a heat absorber. In the refrigerant circuit, a hermetic refrigeration compressor, a radiator, a pressure reducer, and a heat absorber are connected in an annular manner by a pipe.

According to the above configuration, in the hermetic refrigeration compressor, the low-viscosity lubricating oil is used; the sliding area is reduced; and the shaft portion has high reliability. Since the refrigerating and freezing apparatus includes the hermetic refrigerating compressor, which is efficient and highly reliable, power consumption of the refrigerating and freezing apparatus can be reduced, and the refrigerating and freezing apparatus can also be made highly reliable.

The above objects, other objects, features and advantages of the present invention will be more fully apparent from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings.

Advantageous effects of the invention

The present invention is constructed as described above, and has an advantage of being able to provide a sealed refrigeration compressor capable of achieving high reliability of a shaft portion pivotally supported by a bearing portion even if lubricating oil having low viscosity is used.

Drawings

Fig. 1 is a schematic cross-sectional view showing one example of the configuration of a refrigeration compressor according to an embodiment of the present disclosure. Fig. 2 is a schematic side view showing one example of the configuration of a crankshaft included in the refrigeration compressor shown in fig. 1. Fig. 3A is a schematic diagram showing one configuration example in the case where the sliding surface of the crankshaft shown in fig. 2 is a single sliding surface; and fig. 3B and 3C are schematic views each showing one configuration example in the case where the sliding surface of the crankshaft shown in fig. 2 is divided into multiple sliding surfaces.

Fig. 4 is a schematic view showing one example of a configuration of a refrigerating and freezing apparatus including the refrigeration compressor shown in fig. 1.

Detailed Description

The hermetic refrigeration compressor according to the present disclosure includes a hermetic container in which a kinematic viscosity at 40 ℃ of 1mm is stored ² S to 9mm ² Lubricating oil in the range of/S, the sealed container containing an electrical component and a compression component driven by the electrical component and configured to compress a refrigerant. The compression element includes: a shaft portion which is a crankshaft including a main shaft and an eccentric shaft; and a bearing portion pivotally supporting the shaft portion, the bearing portion including a main bearing pivotally supporting the main shaft and an eccentric bearing pivotally supporting the eccentric shaft. The main shaft comprises a sliding surface sliding on the main bearing, which sliding surface is a single sliding surface or divided into multiple sliding surfaces. In the case where the sliding surface is a single sliding surface, the length of the single sliding surface in the axial direction is a single sliding length L, and in the case where the sliding surface is divided into multiple sliding surfaces, the length of one of the multiple sliding surfaces (one sliding surface having a minimum length in the axial direction between the multiple sliding surfaces) in the axial direction is a single sliding length L, and the ratio L/D of the single sliding length L to the outer diameter D of the spindle is less than or equal to 0.51. Lubricating oils contain a slip modifier which is sulfur or a sulfur-containing compound.

According to the above configuration, the lubricating oil is a low-viscosity oil; the ratio L/D of the single sliding length L to the outer diameter D is less than or equal to 0.51 regardless of whether the sliding surface of the main shaft is a single sliding surface or a multiple sliding surface; and the lubricating oil contains a sulfur-based sliding modifier. Because of these features, even if the lubricating oil is a low-viscosity oil and the sliding region is reduced so that the ratio L/D is less than or equal to 0.51, good wear resistance of the sliding portion can be achieved by the sulfur-based sliding modifier. Therefore, even if a lubricating oil having a low viscosity is used, a sealed refrigeration compressor can be obtained that can achieve high reliability of the shaft portion pivotally supported by the bearing portion.

In the hermetic-type refrigeration compressor constructed as above, in the case where the sliding surface is divided into the multiple sliding surfaces, when the sum of lengths of the multiple sliding surfaces in the axial direction is the total sliding length Lt, the ratio Lt/D of the total sliding length Lt to the outer diameter D may be less than or equal to 1.26.

According to the above configuration, in the case where the sliding surface is divided into multiple sliding surfaces, the sliding region is reduced so that not only the ratio L/D is less than or equal to 0.51, but also the ratio Lt/D of the total sliding length Lt to the outer diameter D is less than or equal to 1.26. Therefore, in a state where a low-viscosity lubricating oil is used and the sliding region is reduced, the abrasion resistance of the sliding portion derived from the sulfur-based sliding modifier can be further improved.

In the hermetic refrigeration compressor constructed as above, the ratio L/D may be greater than or equal to 0.15.

According to the above configuration, if the ratio L/D is greater than or equal to 0.15, the sliding region is not excessively reduced. Therefore, in a state where a low-viscosity lubricating oil is used and a sliding region is reduced, appropriate wear resistance of the sliding portion can be achieved by the sulfur-based sliding modifier.

In the hermetic refrigeration compressor constructed as above, the ratio Lt/D may be greater than or equal to 0.3.

According to the above configuration, if the ratio Lt/D is greater than or equal to 0.3, the sliding region is not excessively reduced even in the case where the sliding surface is divided into multiple sliding surfaces. Therefore, in a state where a low-viscosity lubricating oil is used and a sliding region is reduced, appropriate wear resistance of the sliding portion can be achieved by the sulfur-based sliding modifier.

In the hermetic refrigeration compressor configured as above, the content of the sliding modifier in the lubricating oil may be 100ppm or more in terms of the atomic weight of sulfur.

According to the above configuration, the sulfur-based sliding modifier is added to the lubricating oil such that the content of the sliding modifier therein is 100ppm or more in terms of the atomic weight of sulfur. Therefore, in a state where a low-viscosity lubricating oil is used and the sliding region is reduced, suitable wear resistance of the sliding portion derived from the sulfur-based sliding modifier can be achieved.

In the hermetic refrigeration compressor constructed as above, the lubricating oil may further contain a phosphorus base pressure additive.

According to the above configuration, the phosphorus base pressure additive is added to the lubricating oil in addition to the sulfur-based sliding modifier, so that, for example, the abrasion of the sliding portion can be advantageously reduced.

In the hermetic refrigeration compressor configured as above, the electric element may be driven by the inverter at a plurality of operation frequencies.

According to the above configuration, when the electric element is inverter-driven, the abrasion resistance of the sliding portion due to the sulfur-based sliding modifier can be achieved regardless of whether the electric element is operated at a low speed or at a high speed. Therefore, the reliability of the hermetic refrigeration compressor can be improved.

A refrigeration and chiller according to the present disclosure includes a refrigerant circuit comprising: the hermetic refrigeration compressor constructed as above; a heat sink; a pressure reducer; and a heat sink. In the refrigerant circuit, a hermetic refrigeration compressor, a radiator, a pressure reducer, and a heat absorber are connected in an annular manner by a pipe.

Hereinafter, representative embodiments of the present invention are described with reference to the accompanying drawings. In the drawings, the same or corresponding elements are denoted by the same reference numerals, and the repetition of the same description is avoided below.

Example one

[ Structure of refrigeration compressor ]

First, a representative configuration example of a hermetic refrigeration compressor according to embodiment 1 of the present disclosure is specifically described with reference to fig. 1 and 2. Fig. 1 is a schematic cross-sectional view showing one example of the configuration of a hermetic refrigeration compressor 100 according to embodiment 1 of the present disclosure (hereinafter, the hermetic refrigeration compressor 100 may be simply referred to as "refrigeration compressor 100"). Fig. 2 is a schematic side view showing one example of the configuration of the crankshaft 108, the crankshaft 108 being a shaft portion included in the refrigeration compressor 100.

As shown in fig. 1, the refrigeration compressor 100 includes a hermetic container 101 filled with a refrigerant (e.g., R600 a). Mineral oil is stored as lubricating oil 103 in the bottom of sealed container 101. In the present disclosure, the lubricating oil 103 has a viscosity of at least 1mm at 40 DEG C ² S to 9mm ² Kinematic viscosity in the range of/S. It should be noted that, in embodiment 1, although the lubricating oil 103 is a low-viscosity mineral oil, the lubricating oil 103 is not limited to the following. Further, as described below, the lubricating oil 103 contains at least a sulfur-based sliding modifier (or wear inhibitor). The lubricating oil 103 may further comprise extreme pressure additives.

Further, an electric element 106 and a compression element 107 are housed in the sealed container 101. The electric element 106 is constituted by the stator 104 and the rotor 105. Compression element 107 is a reciprocating element driven by electrical element 106. Compression element 107 includes, for example, crankshaft 108, cylinder block 112, and piston 120.

As also shown in fig. 2, the crankshaft 108 is composed of a main shaft 109 and an eccentric shaft 110. The rotor 105 is fixed to the main shaft 109 by press fitting. The eccentric shaft 110 is formed to be eccentric to the main shaft 109. In embodiment 1, the outer peripheral surface of the main shaft 109 of the crankshaft 108 includes a first sliding surface 111a, a second sliding surface 111b, and a non-sliding outer peripheral surface 111c. In addition, an oil feed pump, not shown, is provided at the lower end of the crankshaft 108.

In embodiment 1, for example, the cylinder block 112 is made of cast iron. The cylinder block 112 forms a generally cylindrical bore 113 and includes a main bearing 114, the main bearing 114 pivotally supporting the main shaft 109 of the crankshaft 108. The inner peripheral surface of the main bearing 114 is in sliding contact with the first sliding surface 111a and the second sliding surface 111b of the outer peripheral surface of the main shaft 109, but is not in contact with the non-sliding outer peripheral surface 111c.

As shown in fig. 1, the eccentric shaft 110 of the crankshaft 108 is located at the upper side of the refrigeration compressor 100, and the main shaft 109 of the crankshaft 108 is located at the lower side of the refrigeration compressor 100. Therefore, when the position on the crankshaft 108 is described herein, the upper-lower positional relationship (direction) is utilized. For example, an upper end of the eccentric shaft 110 faces an inner upper surface of the hermetic container 101, and a lower end of the eccentric shaft 110 is connected to the main shaft 109. The upper end of the main shaft 109 is connected to the eccentric shaft 110, and the lower end of the main shaft 109 faces the inner lower surface of the hermetic container 101. The lower end of the main shaft 109 is immersed in the lubricating oil 103.

In the present disclosure, the term "sliding surface" refers to a surface that is a portion of the outer peripheral surface of the shaft portion, which portion is in slidable contact with the inner peripheral surface of the bearing portion. The non-sliding outer peripheral surface 111c constitutes a part of the outer peripheral surface of the main shaft 109. However, unlike the first sliding surface 111a and the second sliding surface 111b, the non-sliding outer peripheral surface 111c is a surface recessed (or recessed) from the sliding surfaces (the first sliding surface 111a and the second sliding surface 111 b) so that the non-sliding outer peripheral surface 111c is not in contact with the inner peripheral surface of the bearing portion. In other words, the diameter or radius of the portion of the main shaft 109 serving as the sliding surface is larger than the diameter or radius of the portion of the main shaft 109 serving as the non-sliding outer peripheral surface 111 c.

The piston 120 is reciprocally inserted into the bore 113, thereby forming a compression chamber 121. A piston pin 115 having, for example, a substantially cylindrical shape is arranged parallel to the eccentric shaft 110. The piston pin 115 is non-rotatably locked to a piston pin bore formed in the piston 120.

The coupler 117 is constituted by, for example, an aluminum casting. The coupler 117 includes an eccentric bearing 119 pivotally supporting the eccentric shaft 110, and the coupler 117 couples the eccentric shaft 110 and the piston 120 via the piston pin 115. The end face of the bore 113 is sealed by a valve plate 122.

It should be noted that in the present disclosure, the main shaft 109 and the eccentric shaft 110 included in the crankshaft 108 are collectively referred to as "shaft portions". Further, the main bearing 114 (pivotally supporting the main shaft 109) of the cylinder block 112 and the eccentric bearing 119 (pivotally supporting the eccentric shaft 110) of the coupling 117 are collectively referred to as "bearing portions".

Cylinder head 123 forms a high pressure chamber (not shown) and is secured to valve plate 122 at the opposite side of bore 113. A suction pipe (not shown) is fixed to the hermetic container 101 and connected to a low pressure side (not shown) of the refrigeration cycle, the suction pipe introducing refrigerant gas into the hermetic container 101. The suction muffler 124 is held in a sandwiched manner between the valve plate 122 and the cylinder head 123.

The main shaft 109 and the main bearing 114 of the crankshaft 108, the piston 120 and the hole 113, the connecting rod of the piston pin 115 and the coupling 117, the eccentric shaft 110 of the crankshaft 108 and the eccentric bearing 119 of the coupling 117, and the like form sliding portions with each other.

In the thus configured refrigeration compressor 100, first, electric power supplied from a commercial power source (not shown) is supplied to the electric element 106 to rotate the rotor 105 of the electric assembly 106. Rotor 105 rotates crankshaft 108 and eccentric motion of eccentric shaft 110 from coupler 117 drives piston 120 via piston pin 115. The piston 120 reciprocates in the hole 113, and the refrigerant gas, which has been introduced into the hermetic container 101 through the suction pipe, is sucked from the suction muffler 124 and compressed in the compression chamber 121.

Here, the specific method for driving the refrigeration compressor 100 is not particularly limited. For example, the refrigeration compressor 100 may be driven by simple on-off control, or may be driven by an inverter at multiple operating frequencies. In the case where the refrigeration compressor 100 is driven by an inverter, in order to optimize the operation control of the refrigeration compressor 100, a low-speed operation or a high-speed operation is performed. When the low-speed operation is performed, the amount of oil supplied to each sliding portion decreases, and when the high-speed operation is performed, the rotational speed of the electric element 106 increases. Here, in the refrigeration compressor 100, the wear resistance of the main shaft 109 can be improved as described below. Therefore, the reliability of the refrigeration compressor 100 can be improved.

In the multiple sliding portions included in the refrigeration compressor 100, the main shaft 109 of the crankshaft 108 is rotatably adapted to the main bearing 114 to constitute the sliding portions. Therefore, for convenience of explanation, the sliding portion composed of the main shaft 109 and the main bearing 114 is referred to as a "main shaft sliding portion". Similarly, the eccentric shaft 110 of the crankshaft 108 is rotatably adapted to an eccentric bearing 119 to constitute a sliding portion. Therefore, for convenience of explanation, the sliding portion formed by the eccentric shaft 110 and the eccentric bearing 119 is referred to as an "eccentric shaft sliding portion". Further, the "main shaft sliding portion" and the "eccentric shaft sliding portion" are collectively referred to as "shaft sliding portion".

The oil feed pump supplies the lubricating oil 103 to each sliding portion as the crankshaft 108 rotates, thereby lubricating each sliding portion. It should be noted that the lubricating oil 103 serves as a seal between the piston 120 and the bore 113.

[ Structure of shaft sliding portion ]

Next, one example of a specific configuration of the shaft sliding portion according to the present disclosure is specifically described with reference to fig. 3A to 3C. Fig. 3A is a schematic diagram showing one configuration example in the case where the sliding surface of the crankshaft 108 shown in fig. 2 is a single sliding surface. Fig. 3B and 3C are schematic diagrams each showing one configuration example in the case where the sliding surface of the crankshaft 108 shown in fig. 2 is divided into multiple sliding surfaces.

In the example shown in fig. 2, the main shaft 109 (which is a shaft portion) of the crankshaft 108 is configured to include a first sliding surface 111a and a second sliding surface 111b. In other words, the sliding surface of the main shaft 109 is divided into multiple sliding surfaces. The configuration of the spindle 109 is shown in fig. 2, i.e., the configuration in which the sliding surface is divided into two sliding surfaces corresponds to the schematic view shown in fig. 3B. However, the shaft portion according to the present disclosure is not limited thereto. The sliding surface of the spindle 109 may be a single sliding surface. For example, as shown in fig. 3A, the outer peripheral surface of the main shaft 109 does not need to be divided into multiple sliding surfaces, but the main shaft 109 may have only one sliding surface 111.

The specific manner of dividing the sliding surface into multiple sliding surfaces is not particularly limited. Typically, between the multiple sliding surfaces, a recess may be formed that is recessed (or depressed) from the sliding surface toward the central axis. The concave portion constitutes a non-sliding outer peripheral surface 111c shown in fig. 2 and 3B. The specific shape of the concave portion is not particularly limited. For example, the depth of the recess may be set to any depth as long as the set depth does not affect, for example, the rigidity and strength of the spindle 109. Similarly, the width of the recess (i.e., the distance between the multiple sliding surfaces) is not particularly limited. The width of the concave portion may be appropriately set according to the degree to which the sliding surface is reduced (i.e., according to the intended reduction or decrease in the sliding region).

In the case of dividing the sliding surface into multiple sliding surfaces, the multiple sliding surfaces are not particularly limited to a specific number of surfaces. As shown in fig. 2 and 3B, the sliding surface may be divided into a first sliding surface 111a and a second sliding surface 111B, i.e., a total of two sliding surfaces. Alternatively, as shown in fig. 3C, the sliding surface may be divided into a first sliding surface 111d, a second sliding surface 111e, and a third sliding surface 111f, that is, three sliding surfaces in total, or may be divided into four or more sliding surfaces. In the configuration shown in fig. 3C, a first non-sliding outer peripheral surface 111g, which is the same recess as the non-sliding outer peripheral surface 111C, is located between the first sliding surface 111d and the second sliding surface 111e, and a second non-sliding outer peripheral surface 111h is located between the second sliding surface 111e and the third sliding surface 111 f.

In the present disclosure, the ratio of the length of the sliding surface of the shaft portion in the axial direction to the outer diameter (diameter) of a portion of the shaft portion (portion serving as the sliding surface) is set to be less than or equal to a predetermined value, so that the sliding region can be reduced without substantially affecting the wear resistance. Specifically, in the case where the sliding surface is a single sliding surface (see, for example, fig. 3A), the length of the single sliding surface in the axial direction is a single sliding length L, and in the case where the sliding surface is divided into multiple sliding surfaces (see, for example, fig. 3B or fig. 3C), the length of one of the multiple sliding surfaces (one sliding surface having the smallest length in the axial direction between the multiple sliding surfaces) in the axial direction is a single sliding length L. Here, when the outer diameter (diameter) of a portion of the shaft portion (portion that is a sliding surface) is the outer diameter D, the shaft portion is designed such that the ratio L/D of the single sliding length L to the outer diameter D of the shaft portion is less than or equal to 0.51.

For ease of description of the outer diameter D and the single sliding length L, fig. 3A shows that the length L of the single sliding surface 111 (i.e., the single sliding length L) is greater than the outer diameter D. If the length L of the single sliding surface 111 is exactly as shown in FIG. 3A with respect to the outer diameter D, the ratio L/D is greater than 0.51. However, in practice, for example, by forming a concave portion (non-sliding outer peripheral surface) on an upper portion (eccentric shaft 110 side) or a lower portion (lubricating oil 103 side) of the main shaft 109 as seen from the single sliding surface 111, the ratio L/D may be set to be less than or equal to 0.51 (L/D. Ltoreq.0.51).

In fig. 3B, the sliding surface is divided into a first sliding surface 111a and a second sliding surface 111B. In the example shown in fig. 3B, the length La of the upper first sliding surface 111a in the axial direction is smaller than the length Lb of the lower second sliding surface 111B in the axial direction (La < Lb). In this case, the first sliding surface 111a is a "sliding surface having a minimum length". Therefore, the length La of the first sliding surface 111a is a single sliding length L (l=la). In this example, la/D needs to be less than or equal to 0.51 on the first sliding surface 111 a.

It should be noted that, similarly to fig. 3A, fig. 3B shows that the length La of the first sliding surface 111a is larger than the outer diameter D for convenience of description of the outer diameter D and the length La. Also in this case, the ratio L/D may be set to be less than or equal to 0.51 by, for example, increasing the length of the non-sliding outer peripheral surface 111c in the axial direction or forming a non-sliding outer peripheral surface (concave portion) not shown on the upper side of the first sliding surface 111 a.

In fig. 3C, the sliding surfaces are divided into a first sliding surface 111d, a second sliding surface 111e, and a third sliding surface 111f. In the example shown in fig. 3C, the length Le in the axial direction of the intermediate second sliding surface 111e is smaller than the length Ld in the axial direction of the upper first sliding surface 111d, and the length Ld is smaller than the length Lf in the axial direction of the lower third sliding surface 111f (Le < Ld < Lf). In this case, the second sliding surface 111e is a "sliding surface having a minimum length". Therefore, the length Le of the second sliding surface 111e is a single sliding length L (l=le). In this example, on the second sliding surface 111e, le/D is required to be less than or equal to 0.51.

In the present disclosure, the lower limit value of the ratio L/D is not particularly limited. One preferable example of the lower limit value is 0.15 or more. Therefore, a preferable range of the ratio L/D in the present disclosure is a range of 0.15 to 0.51. The lower limit of the more preferable ratio L/D is 0.30. A further preferred lower limit of the ratio L/D is 0.42.

In the case where the ratio L/D is greater than 0.51, if a low viscosity oil is used (kinematic viscosity at 40 ℃ C. At 1mm ² S to 9mm ² In the range of/S) as the lubricating oil 103, sufficient wear resistance cannot be obtained even if the above-described sulfur-based sliding modifier (to be described later) is added to the lubricating oil 103. On the other hand, in the case where the ratio L/D is less than 0.15, there is a risk that the sliding surface becomes too narrow, although depending on various conditions of the shaft portion. In general, if the ratio L/D is greater than or equal to 0.15, the sliding region is not excessively reduced. Therefore, even if low-viscosity oil is used as the lubricating oil 103, appropriate wear resistance of the shaft sliding portion can be achieved by the sulfur-based sliding modifier.

In the present disclosure, in the case where the sliding surface is divided into multiple sliding surfaces, it is preferable that the ratio L/D not only satisfies the condition of less than or equal to 0.51, but also satisfies the following condition: when the sum of lengths of the multiple sliding surfaces in the axial direction is a total sliding length Lt, a ratio Lt/D of the total sliding length Lt to the outer diameter D is less than or equal to 1.26 (Lt/D. Ltoreq.1.26).

For example, in the example shown in fig. 3B, the sum of the length La of the first sliding surface 111a and the length Lb of the second sliding surface 111B is set to the total sliding length Lt (lt=la+lb). Therefore, in this example, la+Lb.ltoreq.1.26 is sufficient. In the example shown in fig. 3C, the sum of the length La of the first sliding surface 111d, the length Le of the second sliding surface 111e, and the length Lf of the third sliding surface 111f is set to be the total sliding length Lt (lt=ld+le+lf). Therefore, in this example, ld+Le+Lf.ltoreq.1.26 is sufficient.

As described above, in the case where the sliding surface is divided into multiple sliding surfaces, if the ratio L/D is less than or equal to 0.51 and the ratio Lt/D is less than or equal to 1.26, the abrasion resistance of the shaft sliding member derived from the sulfur-based sliding modifier can be further improved in a state where low viscosity oil is used as the lubricating oil 103 and the sliding region is reduced.

In the present disclosure, the lower limit value of the ratio Lt/D is not particularly limited. One preferable example of the lower limit value is 0.3 or more. Accordingly, the preferred range of the ratio Lt/D in the present disclosure is 0.3 to 1.26. The lower limit of the more preferable ratio Lt/D is 0.60. A further preferred lower limit of the ratio Lt/D is 0.99. In general, if the ratio Lt/D is greater than or equal to 0.3, the sliding region is not excessively reduced even in the case where the sliding surface is divided into multiple sliding surfaces. Therefore, even if low-viscosity oil is used as the lubricating oil 103, appropriate wear resistance of the shaft sliding portion can be achieved by the sulfur-based sliding modifier.

It should be noted that in the example shown in fig. 3A to 3C, the main shaft 109 of the crankshaft 108 is referred to as a shaft portion, and description is made about the main shaft 109 with respect to the ratio L/D and the ratio Lt/D. However, the present disclosure is not so limited. As does the eccentric shaft 110. Specifically, in the case where the sliding surface of the eccentric shaft 110 (which is configured to slide on the eccentric bearing 119) is a single sliding surface, the length of the single sliding surface in the axial direction is a single sliding length L, and in the case where the sliding surface of the eccentric shaft 110 is divided into multiple sliding surfaces, the length in the axial direction of one of the multiple sliding surfaces having the smallest length in the axial direction is a single sliding length L. In these cases, the ratio L/D of the single sliding length L to the outer diameter D of the eccentric shaft 110 needs to be less than or equal to 0.51. Further, when the sum of the lengths of the multiple sliding surfaces of the eccentric shaft 110 in the axial direction is the total sliding length Lt, the ratio Lt/D of the total sliding length Lt to the outer diameter D of the eccentric shaft 110 needs to be less than or equal to 1.26.

Therefore, in the refrigeration compressor 100 according to the present disclosure, at least one of the main shaft 109 and the eccentric shaft 110 constituting the shaft portion needs to have a ratio L/D of less than or equal to 0.51. Similarly, at least one of the main shaft 109 and the eccentric shaft 110 needs to have a ratio Lt/D of less than or equal to 1.26.

[ constitution of lubricating oil ]

Next, a more specific structure of the lubricating oil 103 stored in the sealed container 101 will be specifically described.

The lubricating oil 103 according to the present disclosure is not particularly limited as long as the lubricating oil 103 has a lubricating oil viscosity of 1mm at 40 ℃ ² S to 9mm ² Kinematic viscosity in the range of/S is sufficient. Typically, for example, at least one selected from mineral oil, alkylbenzene oil and ester oil can be suitably usedOily substances are used as the lubricating oil 103. Only one of these oily substances may be used as the lubricating oil 103, or an appropriate combination of two or more oily substances may be used as the lubricating oil 103. The definition of a combination of two or more oily substances herein includes not only a combination of two different oily substances, which are, for example, both mineral oils, but also, for example, at least one oily substance as mineral oil and at least one oily substance as alkylbenzene oil (or at least one oily substance as ester oil).

The lubricating oil 103 of the present disclosure contains not only the above-described oily substance(s) but also the above-described sulfur-based sliding modifier. The sulfur-based slip modifier may be any sulfur-based slip modifier as long as the sulfur-based slip modifier allows the material of the shaft portion (shaft portion material) and sulfur to react with each other. Thus, the slip modifier may be sulfur, or may be a sulfur compound that contains sulfur and reacts with the shaft portion material. For example, if the material of the shaft portion is a ferrous material, examples of sulfur compounds that may be used as slip modifiers include sulfurized olefins, sulfide-based compounds (e.g., dibenzyl disulfide (DBDS), etc.), xanthates, thiadiazoles, thiocarbonates, sulfurized oils or fats, sulfurized esters, dithiocarbamates, sulfurized terpenes, and the like.

The content of the sulfur-based sliding modifier in the lubricating oil 103 is not particularly limited. Preferably, the sliding modifier is added to the lubricating oil 103 such that the content of the sliding modifier therein is 100ppm or more in terms of sulfur atomic weight. The lower limit value of the addition amount of the slip modifier (i.e., the lower limit value of the slip modifier content) which is 100ppm in terms of the atomic weight of sulfur is larger than the upper limit value of the general addition amount of the sulfur base pressure additive which will be described later.

If the content of the sliding modifier (the addition amount of the sliding modifier) is less than 100ppm in terms of the atomic weight of sulfur, although depending on various conditions, there is a risk that proper wear resistance of the shaft sliding portion cannot be achieved in a state where low-viscosity oil is used as the lubricating oil 103 and the sliding region of the shaft sliding portion is reduced. The preferred lower limit of the sulfur-based slip modifier content is, for example, 150ppm or more in terms of the atomic weight of sulfur. Further, the preferable upper limit of the sulfur-based slip modifier content is, for example, 1000ppm or less, more preferably 500ppm or less, based on the atomic weight of sulfur.

The same compounds as known sulfur-based extreme pressure additives may be used as sulfur-based slip modifiers in the present disclosure. Alternatively, however, compounds that react more readily with shaft portion materials than known extreme pressure additives may be used as sulfur-based slip modifiers in the present disclosure. Further alternatively, known extreme pressure additives that are greater than the usual additive amount (i.e., greater than the usual additive content) may be added to the lubricating oil 103.

In general, an extreme pressure additive is a compound containing an active element such as sulfur, halogen, or phosphorus, and chemically reacts with the surface of a material from which the sliding portion is made (i.e., chemically reacts with the sliding surface) to form a film. The presence of the film suppresses, for example, abrasion, seizing or fusion of the sliding member.

Sulfur-containing compounds are known to react readily with copper. For example, reference 1 (japanese laid-open patent application publication No. 2006-117720) discloses that although a sulfur-containing antiwear agent is effective for preventing corrosive wear of a lead-containing sliding member, such sulfur-containing antiwear agent tends to cause sulfidation corrosion of a sliding member containing a non-iron-based metal other than lead, for example, copper (see paragraphs [0006] to [0007] of reference 1).

In the refrigeration compressor 100, copper wires are used as windings of the electrical component 106. In the refrigerating and freezing apparatus using the refrigeration compressor 100, copper pipes are generally used as refrigerant pipes. As previously mentioned, copper tends to corrode by reacting with sulfur-containing compounds. Therefore, in the case of using the sulfur base pressure additive, it is necessary to take measures to prevent or hinder corrosion of the copper-made member (or copper-containing member) of the refrigeration compressor 100 or the refrigeration and freezing apparatus, thereby preventing a decrease in reliability.

The applicant of the present application disclosed in reference 2 (japanese patent No. 5671695) that in the case of using a sulfur base pressure additive in refrigerating machine oil of a refrigerating and freezing apparatus, a sulfur base pressure additive in which the number of sulfur crosslinks is 3 or less is used so that the sulfur base pressure additive does not react with copper in a refrigerant circulation passage. Preferably, a metal deactivator is used with the sulfur base pressure additive.

In this regard, the inventors of the present invention conducted intensive studies including experimental verification. As a result of the study, they found that in the case of using a low-viscosity oil as the lubricating oil 103 and reducing the sliding region of the shaft sliding portion so that the above-mentioned ratio L/D is less than or equal to 0.51, not only good wear resistance was achieved, but also corrosion of a part made of copper (or a copper-containing part) could be substantially avoided by using a sulfur-based compound having higher reactivity as the sliding modifier or by increasing the addition amount of the sliding modifier (i.e., by increasing the content of the sliding modifier).

Further, in the refrigeration compressor 100 according to the present disclosure, a known extreme pressure additive may be added to the lubricating oil 103 in addition to the sulfur-based sliding modifier. The specific extreme pressure additive to be added to the lubricating oil 103 is not particularly limited, and known extreme pressure additives can be suitably used. Examples of known extreme pressure additives that may be suitably used include phosphorus-based compounds (e.g., phosphate esters) and halogenated compounds (e.g., chlorinated hydrocarbons or fluorinated hydrocarbons). Only one of these extreme pressure additives may be added to the lubricating oil composition, or a suitable combination of two or more extreme pressure additives may be added to the lubricating oil composition.

Among these extreme pressure additives, phosphorus-based compounds may be preferably used. Typical examples of the phosphorus-based compound include tricresyl phosphate (TCP), tributyl phosphate (TBP), and triphenyl phosphate (TPP). Among them, TCP is particularly preferable. In addition to the sulfur-based sliding modifier, a phosphorus base pressure additive may be added to the lubricating oil 103, so that, for example, wear of the shaft sliding portion may be advantageously reduced.

The amount of the extreme pressure additive added to the lubricating oil composition is not particularly limited. For example, in the case where the lubricating oil 103 (oily substance) is a low-polarity substance such as mineral oil or alkylbenzene oil, a suitable addition amount of the extreme pressure additive is in the range of 0.5 to 8.0 wt%, more preferably in the range of 1 to 3 wt%.

Further, in the refrigeration compressor 100 according to the present disclosure, various known additives may be added to the lubricating oil 103 in addition to the sliding modifier and the extreme pressure additive. As various additives to be added to the lubricating oil 103, additives known in the field of the lubricating oil 103 can be suitably used. Typical examples of such additives include oiliness agents, antioxidants, acid binding agents, metal deactivators, defoamers, corrosion inhibitors and dispersants. In other words, the lubricating oil 103 used in the refrigeration compressor 100 according to the present disclosure is a lubricating oil composition composed of at least an oily substance and a sliding modifier. The lubricating oil composition may contain extreme pressure additives (especially phosphorus base pressure additives) and may also contain other additives.

As described above, the refrigeration compressor 100 according to the present disclosure satisfies the following conditions: (1) The lubricating oil 103 had a viscosity of 1mm at 40 DEG C ² S to 9mm ² Kinematic viscosity in the range of/S; (2) The ratio L/D of the single sliding length L to the outer diameter D of the shaft portion is less than or equal to 0.51; and (3) use of a sulfur-based slip modifier. Further, in the case where the sliding surface is divided into multiple sliding surfaces, the refrigeration compressor 100 preferably satisfies the following condition (4): the ratio Lt/D of the total sliding length Lt to the outer diameter D is less than or equal to 1.26. By satisfying these conditions, the shaft portion and the bearing portion can be lubricated well, and wear of the shaft sliding portion can be suppressed well. Therefore, the reliability of the refrigeration compressor 100 can be further improved.

It should be noted that the refrigeration compressor 100 according to the present disclosure may be driven with multiple operating frequency inverters as previously described. In the case where the refrigeration compressor 100 is driven by an inverter, there are two operation modes of the electric element 106, in which one mode the electric element 106 operates at a low rotational speed (low-speed operation) and in which the electric element 106 operates at a high rotational speed (high-speed operation). When the electric element 106 is operated at a low rotational speed, the amount of the lubricating oil 103 supplied to the shaft sliding portion is reduced. In the present disclosure, although the sliding region of the shaft sliding portion is reduced, good wear resistance can be achieved even when the amount of the lubricating oil 103 supplied to the shaft sliding portion is reduced.

Further, even when the rotational speed of the electric element 106 is shifted from a low rotational speed to a high rotational speed (i.e., even when the rotational speed of the electric element 106 is increased), good wear resistance can be achieved. Therefore, when the refrigeration compressor 100 is driven by the inverter, the abrasion resistance of the shaft sliding portion due to the sulfur-based sliding modifier can be achieved regardless of whether the low-speed operation or the high-speed operation is being performed. Therefore, the reliability of the refrigeration compressor 100 can be improved, and the operation efficiency can be improved.

As described above, in the refrigeration compressor 100 according to the present disclosure, the lubricating oil 103 is low-viscosity oil, and the ratio L/D of the single sliding length L to the outer diameter D is less than or equal to 0.51, regardless of whether the sliding surface with the shaft portion is a single sliding surface or a multiple sliding surface; and lubricating oil 103 contains a sulfur-based sliding modifier. Because of these features, even if the lubricating oil 103 is a low-viscosity oil and the sliding region is reduced so that the ratio L/D is less than or equal to 0.51, good wear resistance of the sliding portion can be achieved by the sulfur-based sliding modifier. Therefore, a sealed refrigeration compressor can be obtained that can realize high reliability of the shaft portion pivotally supported by the bearing portion even if the lubricating oil 103 having a low viscosity is used.

Example two

In example 2, an example of a refrigerating and freezing apparatus including the refrigeration compressor 100 described in example 1 above will be specifically described with reference to fig. 4. Fig. 4 is a schematic view showing a schematic configuration of a refrigerating and freezing apparatus including the refrigeration compressor 100 of embodiment 1. Therefore, in embodiment 2, the basic configuration of the refrigerating and freezing apparatus is only briefly described.

As shown in fig. 4, the refrigerating and freezing apparatus of embodiment 2 includes, for example, a main body 275, a partition wall 278, and a refrigerant circuit 270. The main body 275 includes an insulating case, a door, etc. The case is configured to have one opening face, and the door is configured to open/close the opening of the case. The interior of the main body 275 is divided into a storage space 276 for the article and a cabinet 277 by a partition wall 278. A blower (not shown) is provided in the storage space 276. It should be noted that the interior of the main body 275 may be divided into, for example, spaces different from the storage space 276 and the machine room 277.

The refrigerant circuit 270 is configured to cool the interior of the storage space 276. For example, the refrigerant circuit 270 includes the refrigeration compressor 100, the radiator 272, the pressure reducer 273, and the heat absorber 274 described in embodiment 1 above, which are connected in an annular manner by pipes. The heat absorber 274 is disposed in the storage space 276. The cooling heat of the heat absorber 274 is agitated by a blower (not shown) to circulate in the storage space 276 as indicated by a dotted arrow in fig. 4. In this way, the interior of the storage space 276 is cooled.

As described above in embodiment 1, the refrigeration compressor 100 included in the refrigerant circuit 270 satisfies the following conditions: (1) The lubricating oil 103 had a viscosity of 1mm at 40 DEG C ² S to 9mm ² Kinematic viscosity in the range of/S; (2) The ratio L/D of the single sliding length L to the outer diameter D of the shaft portion is less than or equal to 0.51; and (3) use of a sulfur-based slip modifier. Further, in the case where the sliding surface is divided into multiple sliding surfaces, the refrigeration compressor 100 preferably satisfies the following condition (4): the ratio Lt/D of the total sliding length Lt to the outer diameter D is less than or equal to 1.26. By satisfying these conditions, the reliability of the refrigeration compressor 100 can be further improved.

As described above, the refrigerating and freezing apparatus of embodiment 2 includes the refrigeration compressor 100 of embodiment 1. In the refrigeration compressor 100, a low-viscosity lubricating oil 103 is used; the sliding area of the shaft sliding part is reduced; and the reliability of the shaft portion improves. Since the refrigerating and freezing apparatus includes the hermetic refrigerating compressor, which is efficient and highly reliable, power consumption of the refrigerating and freezing apparatus can be reduced, and the refrigerating and freezing apparatus can also be made highly reliable.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the claims. Embodiments obtained by appropriately combining technical means disclosed in the different embodiments and modifications also fall within the technical scope of the present invention.

Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions. Therefore, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the invention. Construction and/or functional details may be substantially modified within the scope of the present invention.

Industrial applicability

As described above, the present invention can provide a refrigeration compressor using a low-viscosity lubricating oil and having excellent reliability, and a refrigeration and freezing apparatus using the refrigeration compressor. Therefore, the present invention can be widely applied to various devices using a refrigeration cycle.

List of reference numerals

100 refrigeration compressor

101 sealing container

103 lubricating oil

106 electrical component

107 compression assembly

108 crankshaft

109 spindle (shaft)

110 eccentric shaft (shaft)

111 Single sliding surface

111a first sliding surface

111b second sliding surface

111c non-sliding peripheral surface

111d first sliding surface

111e second sliding surface

111f third sliding surface

111g first non-sliding peripheral surface

111h second non-sliding outer peripheral surface

112 cylinder block

114 main bearing (bearing part)

119 eccentric bearing (bearing part)

270 refrigerant circuit

272 radiator

273 pressure reducer

274 heat absorber

Claims

1. A hermetic refrigeration compressor includes a hermetic container in which a refrigerant is storedWith a kinematic viscosity of 1mm at 40 DEG C ² S to 9mm ² Lubricating oil in the range of/S, the sealed container containing an electrical component and a compression component driven by the electrical component and configured to compress a refrigerant, wherein

The sealed container accommodates a member made of copper or a copper-containing member;

the compression element includes:

a shaft portion which is a crankshaft including a main shaft and an eccentric shaft, the shaft portion being made of a ferrous material, and

a bearing portion pivotally supporting the shaft portion, the bearing portion including a main bearing pivotally supporting the main shaft and an eccentric bearing pivotally supporting the eccentric shaft,

the main shaft includes a sliding surface sliding on the main bearing, the sliding surface being divided into multiple sliding surfaces, wherein an inner peripheral surface of the main bearing is in contact with the multiple sliding surfaces,

the length in the axial direction of one of the multiple sliding surfaces having the smallest length in the axial direction is a single sliding length L, and a ratio L/D of the single sliding length L to an outer diameter D of the main shaft is 0.51 or less and 0.15 or more, and

The lubricating oil contains a sliding modifier which is sulfur or a sulfur-containing compound, wherein the content of sulfur or a sulfur-containing compound as the sliding modifier in the lubricating oil is 100ppm or more in terms of the atomic weight of sulfur.

2. The hermetic refrigeration compressor according to claim 1, wherein

When the sum of the lengths of the multiple sliding surfaces in the axial direction is a total sliding length Lt, a ratio Lt/D of the total sliding length Lt to the outer diameter D is less than or equal to 1.26.

3. The hermetic refrigeration compressor of claim 2, wherein

The ratio Lt/D is greater than or equal to 0.3.

4. A hermetic refrigeration compressor according to any one of claims 1 to 3, wherein

The lubricating oil also includes a phosphorus-based extreme pressure additive.

5. A hermetic refrigeration compressor according to any one of claims 1 to 3, wherein

The electrical components are driven by the inverter at a plurality of operating frequencies.

6. A refrigerated chiller comprising a refrigerant circuit, the refrigerant circuit comprising:

a hermetic refrigeration compressor according to any one of claims 1 to 5;

a heat sink;

a pressure reducer; and

heat absorber in which

In the refrigerant circuit, the hermetic refrigeration compressor, the radiator, the pressure reducer, and the heat absorber are connected in an annular manner by a pipe.