Compressor and refrigeration cycle device

Abstract

The present invention addresses the problem of providing a compressor with improved sliding performance in a sliding part. To solve this problem, a compressor 100 comprises: a high-pressure chamber-type sealed vessel 1 in which are sealed a refrigerant containing 50 mass% or more of a hydrofluoroolefin refrigerant, and a refrigeration oil; and a compression mechanism part 8 which is housed in the sealed vessel 1 and which has a sliding part 9 formed from an iron-based material. The refrigeration oil contains at least one of a polyvinyl ether or a polyolester refrigeration oil, and the kinematic viscosity of the refrigeration oil at 40°C is between 10 mm2 / s and 40 mm2 / s inclusive.

Description

Compressor and refrigeration cycle device

[0001] The present disclosure relates to a compressor and a refrigeration cycle device.

[0002] The R410A refrigerant, which is the mainstream refrigeration cycle device used in refrigerators, freezers, commercial air conditioners, and other such devices, has a high global warming potential (GWP) of 2090, and is therefore being replaced with refrigerants with lower GWP values ​​in order to curb global warming. For example, the R454C refrigerant, a candidate for the next generation of low GWP refrigerants, is a mixed refrigerant containing 78.5% by mass of R1234yf and 21.5% by mass of R32.

[0003] The abstract of Patent Document 1 states, "A composition comprising a refrigerant and a refrigerating machine oil, wherein the refrigerant comprises at least one refrigerant selected from the group consisting of HFO-1141, HFO-1132(E / Z), HFO-1132a, HFO-1123, and HFO-1114, and the refrigerating machine oil has a contact angle of 0.1°≦Θ≦90° with a substrate composed of at least one selected from the group consisting of engineering plastics, organic films, inorganic films, glass, and metal parts."

[0004] Japanese Patent Application Laid-Open No. 2022-132670

[0005] When a hydrofluoroolefin refrigerant (hereinafter referred to as an HFO refrigerant) and a hydrofluorocarbon refrigerant (hereinafter referred to as an HFC refrigerant) are used together, performance such as refrigeration capacity may be reduced compared to when the two refrigerants are not used together, depending on the ratio of the HFO and HFC refrigerants used. For example, when calculating with R454C refrigerant, under rated temperature H in Table 1 of JIS-B8600 "Rated Temperature Conditions for Refrigerant Compressors," the theoretical refrigeration capacity is approximately 35% lower than that of R410A refrigerant. In the case of inverter-driven compressors, increasing the operating speed (rotational speed) can ensure sufficient refrigeration capacity. However, the PV value of the bearing increases with the increase in rotational speed. For this reason, high sliding properties are desirable.

[0006] The invention described in Patent Document 1 considers disproportionation of the refrigerant (paragraph 0059, etc.). However, it does not consider improving the sliding properties of the sliding parts (bearings, etc.) of the compressor. The problem to be solved by the present disclosure is to provide a compressor and a refrigeration cycle device with improved sliding properties of the sliding parts.

[0007] The compressor of the present disclosure comprises a high-pressure chamber-type sealed container in which a refrigerant containing 50% by mass or more of a hydrofluoroolefin refrigerant and a refrigerating machine oil are sealed, and a compression mechanism unit housed in the sealed container and having sliding parts made of an iron-based material, wherein the refrigerating machine oil contains at least one of polyvinyl ether and polyol ester, and the kinetic viscosity of the refrigerating machine oil at 40°C is 10 mm ２ / s or more 40mm ２ / s or less. Other solutions will be described later in the description of the preferred embodiment of the present invention.

[0008] According to the present disclosure, it is possible to provide a compressor and a refrigeration cycle device in which the sliding properties of the sliding parts are improved.

[0009] It is a cross-sectional view showing the compressor of the present disclosure. It is a cross-sectional view showing the vicinity of a sliding part. It is a graph showing the relationship between the type of refrigerant and the kinematic viscosity of refrigerating machine oil, and the PV value. It is a system diagram showing the refrigeration cycle device of the present disclosure.

[0010] Hereinafter, modes for carrying out the present disclosure (hereinafter referred to as "embodiments") will be described with reference to the drawings. In the following description of one embodiment, other embodiments applicable to the one embodiment will also be described as appropriate. The present disclosure is not limited to the one embodiment described below, and different embodiments can be combined with each other or modified as desired without significantly impairing the effects of the present disclosure. Furthermore, the same components will be given the same reference numerals, and duplicate descriptions will be omitted. Furthermore, components having the same functions will be given the same names. The contents shown are merely schematic, and for convenience of illustration, changes may be made from the actual configuration within the scope of not significantly impairing the effects of the present disclosure, and some components may be omitted or modified between drawings. Furthermore, the same embodiment does not necessarily have to include all of the configurations.

[0011] FIG. 1 is a cross-sectional view showing a compressor of the present disclosure. The compressor 100 is a device that compresses a gaseous refrigerant, such as a scroll compressor. The compressor 100 includes a sealed container 1 and a compression mechanism 8 housed in the sealed container 1. The compression mechanism 8 includes a frame 3, a crankshaft 4 (drive shaft), a main bearing 5, and an orbiting bearing 6. A sliding portion 9 is formed at the contact portion between the crankshaft 4 and the main bearing 5. Therefore, the compression mechanism 8 has the sliding portion 9. Note that the sliding portion 9 is not limited to the portion between the crankshaft 4 and the main bearing 5, and may be any sliding portion in the compressor 100.

[0012] The sealed container 1 is a high-pressure chamber type. In addition to the compression mechanism 8, the sealed container 1 also houses an electric motor 7 and the like. The sealed container 1 is filled with a refrigerant containing 50 mass% or more of an HFO refrigerant (hydrofluoroolefin refrigerant) and refrigeration oil. The refrigeration oil also exists as an oil reservoir M at the bottom inside the sealed container 1. The sealed container 1 is equipped with a suction pipe Pa that draws in the refrigerant and a discharge pipe Pb that discharges the refrigerant compressed by the compression mechanism 8. The suction pipe Pa is connected to a suction circuit 13 (FIG. 4) described below. The discharge pipe Pb is connected to a discharge circuit 14 (FIG. 4) described below.

[0013] The compression mechanism 8 is a mechanism that compresses the refrigerant as the crankshaft 4 rotates. The compression mechanism 8 includes a fixed scroll 21 and an orbiting scroll 22. The fixed scroll 21 is a fixed member that is fixed within the sealed container 1. The fixed scroll 21 includes a thick, disk-shaped base plate 21a and a spiral wrap 21b that stands upright on the underside of the base plate 21a. The orbiting scroll 22 is a moving member that forms a compression chamber C between itself and the fixed scroll 21 as it orbits. The orbiting scroll 22 includes a disk-shaped base plate 22a, a spiral wrap 22b that stands upright on the base plate 22a, and a boss portion 22c that fits onto the upper end of the crankshaft 4. The orbiting scroll 22 is supported by the frame 3.

[0014] The compression chambers C are formed between the wraps 21b and 22b. The compression chambers C are spaces for compressing the gaseous refrigerant, and are formed on the outer line side and the inner line side of the wraps 22b. A discharge port V is provided near the center of the base plate 21a to guide the refrigerant compressed in the compression chambers C to the upper space within the sealed container 1.

[0015] The crankshaft 4 extends in the vertical direction and is made of, for example, an iron-based material (carbon steel, chrome-molybdenum steel, etc.). The crankshaft 4 includes a main shaft 4a, a flange 4b ​​connected to the upper side of the main shaft 4a, and an eccentric portion 4c connected to the upper side of the flange 4b. The main bearing 5 rotatably supports the upper part of the crankshaft 4. The main bearing 5 is fixed to the frame 3. The main bearing 5 is, for example, a thrust bearing, and is in rotatable contact with a surface 41 of the crankshaft 4. The slewing bearing 6 rotatably supports the eccentric portion 4c.

[0016] As described above, the sliding portion 9 is formed between the main bearing 5 and the crankshaft 4. The sliding portion 9 is made of an iron-based material, and in the example of the present disclosure, the crankshaft 4 having the surface 41 and the main bearing 5 are made of an iron-based material. The iron-based material here is, for example, carbon steel or chromium-molybdenum steel. These have high hardness, so by using these, it is possible to obtain a compressor 100 that has excellent wear resistance and high reliability.

[0017] 2 is a cross-sectional view showing the vicinity of the sliding portion 9. A film 42 (a physisorption film and a chemisorption film, described later) containing fluorine derived from the HFO refrigerant is formed on a surface 41 of the crankshaft 4 (an example of a member) of the sliding portion 9, which is made of an iron-based material. The film 42 is usually formed by the rotation of the crankshaft 4 during use of the compressor 100 (FIG. 1), but may also be formed before use of the compressor 100 (for example, before shipping from a factory).

[0018] As described above, the refrigerant sealed in sealed container 1 ( FIG. 1 ) contains 50% by mass or more of an HFO refrigerant. The HFO refrigerant is an unsaturated refrigerant that contains double bonds (unsaturated bonds) in its molecules. The double bonds exhibit strong adsorption to surface 41, which is made of an iron-based material, when crankshaft 4 slides against it. As a result, the HFO refrigerant forms a physically adsorbed film (film 42) made of the refrigerant on surface 41. This physically adsorbed film exhibits high sliding properties, improving the sliding properties of crankshaft 4.

[0019] Furthermore, at least a portion of the formed physically adsorbed film is decomposed by frictional heat generated by sliding. As a result, the decomposed physically adsorbed film is transformed into a chemically adsorbed film (film 42) made of a fluorine compound. The chemically adsorbed film exhibits even higher sliding properties with respect to the sliding of the crankshaft 4 than the physically adsorbed film. This further improves the sliding properties of the crankshaft 4 at the sliding portion 9, thereby improving the seizure resistance and reliability of the compressor 100.

[0020] FIG. 3 is a graph showing the relationship between the PV value and the type of refrigerant and the kinematic viscosity of the refrigeration oil. The graph in FIG. 3 is a relative graph, with the bearing PV value at 0.24 on the horizontal axis being 100%. The horizontal axis shows the actual inclination angle of the crankshaft 4 relative to the allowable inclination angle of the crankshaft 4. The closer the value on the horizontal axis is to 1, the greater the inclination of the crankshaft 4. Therefore, the larger the value on the horizontal axis, the more severe the condition of the sliding portion 9. The vertical axis shows the PV value (limit PV value) of the main bearing 5 ( FIG. 2 ). The PV value is the product of the surface pressure (p) and the surface velocity (v) and correlates with frictional heat. The larger the PV value, the higher the sliding properties and durability. Therefore, the smaller the actual inclination angle of the crankshaft 4 relative to the allowable inclination angle of the crankshaft 4, the higher the PV value.

[0021] The solid line graph (Example 1) shows a case where the refrigerant was R454C and the refrigerating machine oil was polyvinyl ether (kinematic viscosity at 40°C: 32 mm ２The dashed line graph (Comparative Example 1) shows the results when R410A was used as the refrigerant and polyvinyl ether (kinematic viscosity at 40°C: 68 mmHg) was used as the refrigerant. R454C is a refrigerant containing 78.5 mass% R1234yf (HFO refrigerant) and 21.5 mass% R32 (HFC refrigerant). ２ R410A is a refrigerant containing 50% by mass of R125 (HFO refrigerant) and 50% by mass of R32 (HFC refrigerant).

[0022] The dashed line graph (Comparative Example 2) shows a case where the refrigerant was R448A and the refrigerant oil was polyvinyl ether (kinematic viscosity at 40°C: 32 mm ２ This is the result of using a refrigerant mixture containing 20% ​​by mass of R1234yf (HFO refrigerant), 7% by mass of R1234ze (HFO refrigerant), 26% by mass of R32 (HFO refrigerant), 26% by mass of R125 (HFC refrigerant), and 21% by mass of R134a (HFO refrigerant). Therefore, R448A contains 27% by mass of HFO refrigerant and 73% by mass of HFC refrigerant.

[0023] The above points are summarized in Table 1 below.

[0024]

[0025] Typically, the higher the kinematic viscosity of the refrigerating machine oil, the higher the sliding properties. Therefore, Comparative Example 1, which has a relatively high kinematic viscosity, exhibits a large PV value, which indicates high sliding properties (durability). However, the graph for Example 1 is located at roughly the same position as the graph for Comparative Example 1. Therefore, it was found that Example 1, which has a relatively low kinematic viscosity, also exhibits high sliding properties (durability). This decrease is thought to be due to the mechanism described above with reference to FIG. 2. That is, since the kinematic viscosity of Example 1 is lower than that of Comparative Example 1, it is thought that the sliding properties would also be low if the refrigerant were not taken into consideration. However, it is thought that the refrigerant of Example 1 acts to compensate for this low sliding properties. In other words, even if the kinematic viscosity of the refrigerating machine oil is low, sliding properties can be improved by using an HFO refrigerant in a predetermined ratio or more.

[0026] From another perspective, the kinematic viscosity of the refrigerating machine oil is the same in Example 1 and Comparative Example 2. Therefore, if only the effects attributable to the refrigerating machine oil are considered, the positions on the graphs for PV values ​​would be approximately the same. However, the ratio of HFO refrigerant in the refrigerant used is completely different. Due to this difference in ratio, the PV value of Example 1 was approximately 20% higher overall than the PV value of Comparative Example 2. Therefore, it was found that, rather than simply using an arbitrary amount of HFO refrigerant, using an HFO refrigerant within the range disclosed herein (containing 50% by mass or more of HFO refrigerant) can improve sliding properties.

[0027] In addition, the refrigerating machine oil sealed in the sealed container 1 (FIG. 1) has a kinematic viscosity of 10 mm at 40°C. ２ / s or more 40mm ２ This allows for high sliding properties to be obtained even when using a refrigerating machine oil with a relatively low kinematic viscosity. ２ By setting the refrigeration oil temperature to 100 / s or less, the viscous resistance, friction resistance, etc. of the refrigeration oil can be kept low, and the efficiency of the compressor 100 can be improved.

[0028] The refrigeration oil contains at least one of polyvinyl ether and polyol ester. Polyvinyl ether, in particular, has high durability against air and water. Therefore, polyvinyl ether can be suitably used in, for example, a refrigeration cycle apparatus 200 (FIG. 4) having a long piping length. On the other hand, polyol ester has lower durability against air and water than polyvinyl ether. Therefore, polyol ester can be suitably used in a refrigeration cycle apparatus 200 (FIG. 4) having a relatively short piping length.

[0029] As described above, the refrigerant sealed in the sealed container 1 ( FIG. 1 ) contains 50% by mass or more (at least 50% by mass) of an HFO refrigerant. The HFO refrigerant content is preferably 70% by mass or more and 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less, of the total amount of the sealed refrigerant. It is preferable to use a combination of an HFO refrigerant and an HFC refrigerant. This combination allows the functions of both the HFO refrigerant and the HFC refrigerant (e.g., sliding properties, refrigeration capacity, etc.) to be fully utilized.

[0030] The HFO refrigerant includes, for example, at least one of R1234yf and R1234ze. These refrigerants have high refrigeration capacity while also having low global warming potential (GWP). Therefore, by including at least one of these refrigerants, it is possible to obtain a high-performance compressor 100 with a low impact on the global environment.

[0031] In this case, the refrigerant preferably contains R32 as at least a portion other than the HFO refrigerant. R32 is widely used and has high refrigeration performance, and among HFC refrigerants, it has a low GWP. Therefore, a high-performance compressor 100 with a low impact on the global environment can be obtained.

[0032] In another embodiment, the HFO refrigerant includes a first refrigerant that is at least one of R1234yf or R1234ze, and a second refrigerant that is at least one of R1132(E) or R1123. The first refrigerant accounts for 50 mass% or more of the entire HFO refrigerant to be charged, and the second refrigerant accounts for less than 50 mass%. This increases the proportion of the first refrigerant, which is at least one of R1234yf or R1234ze, among the HFO refrigerants used, thereby improving their functionality (stability, refrigeration capacity, efficiency, etc.).

[0033] When the second refrigerant contains R1132(E), the first refrigerant is preferably 65 to 100% by mass, more preferably 70 to 85% by mass, and particularly preferably 70 to 80% by mass of the total HFO refrigerant. When the second refrigerant contains R1123, the first refrigerant is preferably 50 to 100% by mass, more preferably 55 to 80% by mass, and particularly preferably 55 to 70% by mass of the total HFO refrigerant.

[0034] FIG. 4 is a system diagram showing a refrigeration cycle apparatus 200 according to the present disclosure. In the illustrated example, the refrigeration cycle apparatus 200 is an air conditioner, but it may also be, for example, a refrigerator, a display case, or the like. The refrigeration cycle apparatus 200 includes a compressor 100, an outdoor heat exchanger 26 (an example of a condenser or evaporator), an electronic expansion valve 27 for heating and an electronic expansion valve 29 for cooling (both examples of expansion mechanisms), and an indoor heat exchanger 11 (an example of an evaporator or condenser). The compressor 100, the outdoor heat exchanger 26, the electronic expansion valves 27 and 29, and the indoor heat exchanger 11 are connected by piping (not shown), thereby circulating refrigerant through a discharge circuit 14, forming a refrigeration cycle. The refrigeration cycle is a closed circuit. A blower 25 is attached to the outdoor heat exchanger 26. A blower 10 is attached to the indoor heat exchanger 11.

[0035] The refrigeration cycle apparatus 200 further includes an oil separator 23 provided in the discharge circuit 14 of the compressor 100, and a series circuit 12 that returns refrigeration oil from the oil separator 23 to the compressor 100. The series circuit 12 is a circuit that returns refrigeration oil to an oil sump M (FIG. 1) formed in the lower inside part of the compressor 100. The refrigeration cycle apparatus 200 further includes a four-way switching valve 24 that switches the circulation direction of the refrigerant, a receiver 28, an accumulator 15, and a suction circuit 13.

[0036] For example, the refrigerant R454C used in the first embodiment can be used in the refrigeration cycle apparatus 200. The refrigeration cycle apparatus 200 includes the compressor 100 described with reference to Figures 1 to 3. This improves the slidability of the sliding parts 9 (Figure 1) of the compressor 100, thereby improving the reliability of the refrigeration cycle apparatus 200.

[0037] REFRIGERATION METHOD AND OPERATION SYSTEM 1: Closed vessel 100: Compressor 11: Indoor heat exchanger 200: Refrigeration cycle device 21: Fixed scroll 22: Orbiting scroll 26: Outdoor heat exchanger 4: Crankshaft 41: Surface 42: Membrane 4a: Main shaft 5: Main bearing 6: Orbiting bearing 8: Compression mechanism 9: Sliding part

Claims

1. A high-pressure chamber type sealed container in which a refrigerant containing 50% or more by mass of a hydrofluoroolefin refrigerant and a refrigerating machine oil are sealed, and a compression mechanism part housed in the sealed container and having a sliding part made of an iron-based material, the refrigerating machine oil containing at least one of polyvinyl ether and polyol ester, and the kinetic viscosity of the refrigerating machine oil at 40°C is 10 mm ２ / s or more 40mm ２ / s or less.

2. The compressor according to claim 1, characterized in that the hydrofluoroolefin refrigerant contains at least one of R1234yf and R1234ze, and the refrigerant contains R32 as at least a portion other than the hydrofluoroolefin refrigerant.

3. The compressor according to claim 1, characterized in that the hydrofluoroolefin refrigerant comprises a first refrigerant which is at least one of R1234yf or R1234ze, and a second refrigerant which is at least one of R1132(E) or R1123, and the first refrigerant is contained in an amount of 50 mass% or more and the second refrigerant is contained in an amount of less than 50 mass% in the entire hydrofluoroolefin refrigerant.

4. The compressor according to claim 1, characterized in that the iron-based material is carbon steel or chrome-molybdenum steel.

5. The compressor according to claim 1, characterized in that a film containing fluorine derived from the hydrofluoroolefin refrigerant is formed on the surface of the member made of the iron-based material among the sliding parts.

6. A compressor, a condenser, an expansion mechanism, and an evaporator, the compressor comprising: a high-pressure chamber type sealed container in which a refrigerant containing 50 mass% or more of a hydrofluoroolefin refrigerant and a refrigerating machine oil are sealed; and a compression mechanism part housed in the sealed container and having a sliding part made of an iron-based material, the refrigerating machine oil containing at least one of polyvinyl ether and polyol ester, and the kinetic viscosity of the refrigerating machine oil at 40°C is 10 mm ２ / s or more 40mm ２ / s or less.

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