Compressor and refrigeration cycle device

Abstract

Provided is a compressor in which the sliding performance of a sliding part is improved. In order to solve this problem, a compressor (100) is provided with: a high-pressure chamber-type sealed container (1) in which refrigerant oil and a refrigerant containing 50 mass% or more of a hydrofluoroolefin refrigerant are sealed; and a compression mechanism part (8) which is housed in the sealed container (1) and has a sliding part (9) made of an iron-based material, the refrigerator oil comprising a polyvinyl ether and / or a polyol ester, and the kinematic viscosity of the refrigerator oil at 40 DEG C being from 10 mm2 / s to 40 mm2 / s (inclusive).

Description

Technical Field

[0001] The present invention relates to a compressor and a refrigeration cycle device. Background Art

[0002] The global warming potential (GWP) of the R410A refrigerant, which is the mainstream refrigerant in refrigerators, freezers, commercial air conditioners and other refrigeration cycle devices, is as high as 2090. In order to suppress global warming, a change to a refrigerant with a lower GWP value is being made. For example, the R454C refrigerant, which is a next-generation low-GWP candidate refrigerant, 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 contact angle of the refrigerating machine oil with a substrate consisting of at least one selected from the group consisting of engineering plastics, organic films, inorganic films, glass, and metal parts is 0.1°≤θ≤90°."

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-132670 Summary of the invention

[0007] Problems to be solved by the invention

[0008] When a hydrofluoroolefin refrigerant (hereinafter referred to as HFO refrigerant) and a hydrofluorocarbon refrigerant (hereinafter referred to as HFC refrigerant) are used together, depending on the usage ratio of the HFO refrigerant to the HFC refrigerant, performance such as refrigeration capacity may sometimes be lower than when they are not used together. For example, when the R454C refrigerant is used for trial calculation, under the rated temperature H conditions of Table 1 of JIS-B8600 "Rated temperature conditions for compressors for refrigerants", the theoretical refrigeration capacity is reduced by about 35% compared to the R410A refrigerant. In order to ensure the refrigeration capacity, in the case of a compressor driven by an inverter, it can be dealt with by increasing the operating speed (rotation speed). However, the PV value of the bearing increases by the amount of increase in the rotation speed. Therefore, it is preferred to have high sliding properties.

[0009] In the invention described in Patent Document 1, the unevenness of the refrigerant is studied (paragraph 0059, etc.), but no study is made on improving the sliding properties in the sliding parts (bearings, etc.) of the compressor.

[0010] An object of the present invention is to provide a compressor and a refrigeration cycle device having improved sliding properties of a sliding portion.

[0011] Means for solving problems

[0012] The compressor of the present invention comprises: a high-pressure chamber type sealed container, which contains refrigeration oil and a refrigerant containing 50% by mass or more of a hydrofluoroolefin refrigerant; and a compression mechanism, which is contained in the sealed container and has a sliding portion made of an iron-based material, wherein the refrigeration oil contains at least one of polyvinyl ether and polyol ester, and the kinematic viscosity of the refrigeration oil at 40° C. is 10 mm2 / s or more and 40 mm2 / s or less. Other solutions will be described later in the mode for implementing the invention.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to provide a compressor and a refrigeration cycle device in which the sliding properties of a sliding portion are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view showing the compressor of the present invention.

[0016] Figure 2 It is a cross-sectional view showing the vicinity of a sliding portion.

[0017] Figure 3 This is a graph showing the relationship between the type of refrigerant and the kinematic viscosity of refrigeration oil and the PV value.

[0018] Figure 4 It is a system diagram showing the refrigeration cycle device of the present invention. DETAILED DESCRIPTION

[0019] Hereinafter, a method for implementing the present invention (referred to as an embodiment) will be described with reference to the accompanying drawings. In the description of one embodiment below, descriptions of other embodiments that can be applied to one embodiment are also appropriately made. The present invention is not limited to one embodiment below, and different embodiments can be combined with each other, or arbitrarily deformed within the scope that does not significantly damage the effect of the present invention. In addition, the same figure mark is marked on the same components, and repeated descriptions are omitted. In addition, the same name is marked on components with the same function. The contents of the drawings are merely schematic, and for the convenience of illustration, sometimes changes are made from the actual structure within the scope that does not significantly damage the effect of the present invention, or the illustration of a part of the components is omitted or deformed between the drawings. In addition, in the same embodiment, it is not necessarily necessary to have all the structures.

[0020] Figure 1: is a cross-sectional view showing the compressor of the present invention. The compressor 100 is a device that compresses a gaseous refrigerant, for example, a scroll compressor. The compressor 100 includes a closed container 1 and a compression mechanism 8 housed in the closed container 1. The compression mechanism 8 includes a frame 3, a crankshaft 4 (drive shaft), a main bearing 5, and a rotary bearing 6. Among them, a sliding portion 9 is formed at a contact portion between the crankshaft 4 and the main bearing 5. Therefore, the compression mechanism 8 has a sliding portion 9. It should be noted that the sliding portion 9 is not limited to between the crankshaft 4 and the main bearing 5, and can be any portion as long as it is a portion that slides in the compressor 100.

[0021] The sealed container 1 is a high-pressure chamber type sealed container. In addition to the compression mechanism 8, the sealed container 1 also contains an electric motor 7 and the like. Refrigeration oil and a refrigerant containing 50% by mass or more of HFO refrigerant (hydrofluoroolefin refrigerant) are sealed in the sealed container 1. The refrigeration oil also exists as an oil storage portion M in the lower inner portion of the sealed container 1. The sealed container 1 has a suction pipe Pa for sucking in the refrigerant and a discharge pipe Pb for discharging the refrigerant compressed by the compression mechanism 8. The suction pipe Pa is connected to the suction circuit 13 ( Figure 4 ) is connected. The discharge pipe Pb is connected to the discharge circuit 14 ( Figure 4 )connect.

[0022] The compression mechanism 8 is a mechanism for compressing 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 fixed in the closed container 1. The fixed scroll 21 includes a thick-walled base plate 21a in the shape of a circular plate and a spiral volute 21b vertically arranged on the lower side of the base plate 21a. The orbiting scroll 22 is a movable member that forms a compression chamber C between the fixed scroll 21 and the fixed scroll 21 by its orbit. The orbiting scroll 22 includes a base plate 22a in the shape of a circular plate, a spiral volute 22b vertically arranged on the base plate 22a, and a boss portion 22c engaged with the upper end portion of the crankshaft 4. The orbiting scroll 22 is supported by the frame 3.

[0023] The compression chamber C is formed between the scroll 21b and the scroll 22b. The compression chamber C is a space for compressing the gaseous refrigerant, and is formed on the outer line side and the inner line side of the scroll 22b, respectively. A discharge port V is provided near the center of the table 21a to guide the refrigerant compressed in the compression chamber C to the upper space in the closed container 1.

[0024] 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 portion 4b connected to the upper side of the main shaft 4a, and an eccentric portion 4c connected to the upper side of the flange portion 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 the surface 41 of the crankshaft 4. The slewing bearing 6 rotatably supports the eccentric portion 4c.

[0025] 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. In the example of the present invention, the crankshaft 4 and the main bearing 5 having the surface 41 are made of an iron-based material. The iron-based material mentioned here is, for example, carbon steel or chrome-molybdenum steel. These have high hardness, so by using them, a compressor 100 with excellent wear resistance and high reliability can be obtained.

[0026] Figure 2 4 is a cross-sectional view showing the vicinity of the sliding portion 9. A film 42 (physical adsorption film and chemical adsorption film described later) containing fluorine from the HFO refrigerant is formed on the surface 41 of the crankshaft 4 (an example of a member) formed of an iron-based material in the sliding portion 9. The film 42 is usually formed by contacting the compressor 100 ( Figure 1 ) is formed by the rotation of the crankshaft 4 accompanying the use of the compressor 100, but may also be formed before the use of the compressor 100 (for example, when the compressor is shipped from the factory).

[0027] As described above, the sealed container 1 ( Figure 1 ) contains 50% by mass or more of HFO refrigerant. HFO refrigerant is an unsaturated refrigerant containing double bonds (unsaturated bonds) in its molecules. In the sliding state of the crankshaft 4, the double bonds show strong adsorption to the surface 41 formed by the iron-based material. Therefore, the HFO refrigerant forms a physical adsorption film (film 42) composed of the refrigerant on the surface 41. As a result, the physical adsorption film shows high sliding properties, so the sliding properties of the crankshaft 4 are improved.

[0028] In addition, at least a portion of the formed physical adsorption film is decomposed by the friction heat generated by sliding. As a result, the decomposed physical adsorption film is changed into a chemical adsorption film (film 42) composed of a fluorine compound. The chemical adsorption film shows higher sliding properties relative to the sliding of the crankshaft 4 than the above-mentioned physical adsorption film. As a result, the sliding properties of the crankshaft 4 on the sliding portion 9 can be further improved, and the sintering resistance and reliability of the compressor 100 can be improved.

[0029] Figure 3 This is a graph showing the relationship between the type of refrigerant and the kinematic viscosity of refrigeration oil and the PV value. Figure 3The graph is a relative graph with the bearing PV value when the horizontal axis is 0.24 as 100%. The horizontal axis represents the actual inclination angle of the crankshaft 4 relative to the allowable inclination angle of the crankshaft 4. It can be said that the closer the value of the horizontal axis is to 1, the greater the inclination of the crankshaft 4. Therefore, it can be said that the larger the value of the horizontal axis, the stricter the condition of the sliding portion 9 becomes. The vertical axis represents the main bearing 5 ( Figure 2 ) PV value (limit PV value). The PV value is the product of the surface pressure (p) and the surface speed (v), and is related to the friction heat. It can be said that the larger the PV value, the higher the sliding property and the better the 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.

[0030] The solid line graph (Example 1) is the result of using R454C as a refrigerant and polyvinyl ether (kinematic viscosity at 40°C is 32 mm2 / s) as a refrigeration oil. R454C is a refrigerant containing R1234yf (HFO refrigerant) at a ratio of 78.5 mass% and R32 (HFC refrigerant) at a ratio of 21.5 mass%. The dotted line graph (Comparative Example 1) is the result of using R410A as a refrigerant and polyvinyl ether (kinematic viscosity at 40°C is 68 mm2 / s) as a refrigeration oil. R410A is a refrigerant containing R125 (HFO refrigerant) at a ratio of 50 mass% and R32 (HFC refrigerant) at a ratio of 50 mass%.

[0031] The single-point dashed line graph (Comparative Example 2) is the result of using R448A as a refrigerant and polyvinyl ether (kinematic viscosity at 40°C is 32 mm2 / s) as a refrigeration oil. R448A is a refrigerant containing R1234yf (HFO refrigerant) at a ratio of 20 mass%, R1234ze (HFO refrigerant) at a ratio of 7 mass%, R32 (HFO refrigerant) at a ratio of 26 mass%, R125 (HFC refrigerant) at a ratio of 26 mass%, and R134a (HFO refrigerant) at a ratio of 21 mass%. Therefore, in R448A, HFO refrigerant is contained at a ratio of 27 mass%, and HFC refrigerant is contained at a ratio of 73 mass%.

[0032] The above points are summarized in Table 1 below.

[0033] Table 1

[0034]

[0035] Generally, the greater the kinematic viscosity of the refrigeration oil, the higher the sliding property. Therefore, in Comparative Example 1 with a relatively high kinematic viscosity, since it shows a large PV value, it can be said that it has high sliding property (durability). However, the graph of Example 1 exists in approximately the same position as the graph of Comparative Example 1. Therefore, it can be seen that Example 1 with a relatively low kinematic viscosity also has high sliding property (durability). It is considered that this reduction is caused by referring to the above Figure 2 That is, the kinematic viscosity of Example 1 is lower than that of Comparative Example 1, so it is considered that the sliding property is also low if the refrigerant is not taken into account, but it is considered that this is because the refrigerant of Example 1 works to compensate for its low degree. In other words, even if the kinematic viscosity of the refrigeration oil is low, the sliding property can be improved by using an HFO refrigerant with a predetermined ratio or more.

[0036] From another point of view, the kinematic viscosity of the refrigeration oil is the same in Example 1 and Comparative Example 2. Therefore, if only the effect caused by the refrigeration oil is considered, it is believed that the position of the graph related to the PV value is roughly the same. However, the ratio of the HFO refrigerant in the refrigerant used is completely different. Due to the difference in such a ratio, the PV value of Example 1 is increased by about 20% as a whole compared to the PV value of Comparative Example 2. Therefore, it can be seen that the sliding property can be improved not by simply using the HFO refrigerant in an arbitrary amount, but by using the HFO refrigerant within the range of the present invention (including more than 50% by mass of HFO refrigerant).

[0037] In addition, regarding the sealed container 1 ( Figure 1 ) in the refrigeration oil, the kinematic viscosity of the refrigeration oil at 40°C is 10 mm 2 / s or more and 40mm 2 / s or less. Thus, even when using a refrigeration oil having a relatively low kinematic viscosity, high sliding properties can be obtained. In particular, by setting the viscosity to 40 mm 2 / s or less, the viscosity resistance, friction resistance, etc. of the refrigeration oil can be suppressed to a low level, thereby improving the efficiency of the compressor 100.

[0038] The refrigeration oil contains at least one of polyvinyl ether and polyol ester. In particular, polyvinyl ether has high durability against air and water. Therefore, polyvinyl ether can be applied to, for example, a refrigeration cycle device 200 ( Figure 4 On the other hand, polyol esters have lower durability against air and water than polyvinyl ethers. Therefore, polyol esters can be applied to refrigeration cycle devices 200 ( Figure 4 ).

[0039] As described above, the sealed container 1 ( Figure 1) contains 50% by mass or more (at least 50% by mass) of HFO refrigerant. The content of HFO refrigerant is preferably 70% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, relative to the entire sealed refrigerant. It is preferred that HFO refrigerant and HFC refrigerant be used in combination. By using them in combination, the functions of HFO refrigerant and HFC refrigerant (such as sliding property, refrigeration capacity, etc.) can be exerted.

[0040] HFO refrigerants include, for example, at least one of R1234yf and R1234ze. They have high refrigeration capacity and, on the other hand, low global warming potential (GWP). Therefore, by including at least one of them, a high-performance compressor 100 with low load on the global environment can be obtained.

[0041] At this time, the refrigerant preferably contains R32 as at least a part other than the HFO refrigerant. R32 is universal and has high refrigeration performance, and has a low GWP among HFC refrigerants. Therefore, the load on the global environment is small, and a high-performance compressor 100 can be obtained.

[0042] In another embodiment, the HFO refrigerant includes a first refrigerant that is at least one of R1234yf and R1234ze and a second refrigerant that is at least one of R1132(E) and R1123. Moreover, in the entire sealed HFO refrigerant, the first refrigerant is contained at a ratio of 50% by mass or more, and the second refrigerant is contained at a ratio of less than 50% by mass. Thus, in the HFO refrigerant used, the ratio of the first refrigerant that is at least one of R1234yf and R1234ze can also be increased, thereby improving the functions (stability, refrigerant capacity, efficiency, etc.) achieved by them.

[0043] When the second refrigerant includes R1132(E), the first refrigerant is preferably 65% ​​by mass or more and 100% by mass or less, more preferably 70% by mass or more and 85% by mass or less, and particularly preferably 70% by mass or more and 80% by mass or less, relative to the entire HFO refrigerant. In addition, when the second refrigerant includes R1123, the first refrigerant is preferably 50% by mass or more and 100% by mass or less, more preferably 55% by mass or more and 80% by mass or less, and particularly preferably 55% by mass or more and 70% by mass or less, relative to the entire HFO refrigerant.

[0044] Figure 4: is a system diagram showing a refrigeration cycle device 200 of the present invention. The refrigeration cycle device 200 is an air conditioner in the example shown in the figure, but it can also be, for example, a refrigerator, a display cabinet, etc. The refrigeration cycle device 200 includes a compressor 100, an outdoor heat exchanger 26 (an example of a condenser or an evaporator), an electronic expansion valve 27 for heating and an electronic expansion valve 29 for cooling (both are examples of expansion mechanisms), and an indoor heat exchanger 11 (an example of an evaporator or a condenser). The compressor 100, the outdoor heat exchanger 26, the electronic expansion valves 27, 29 and the indoor heat exchanger 11 are connected by pipes (not shown), whereby the refrigerant circulates in the discharge circuit 14 to form 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.

[0045] The refrigeration cycle device 200 further includes: an oil separator 23, which is provided in the discharge circuit 14 of the compressor 100; and a series circuit 12, which returns the refrigeration oil from the oil separator 23 to the compressor 100. The series circuit 12 is a circuit for returning the refrigeration oil to the oil storage portion M ( Figure 1 The refrigeration cycle device 200 further includes a four-way switching valve 24 for switching the circulation direction of the refrigerant, a recovery device 28, an accumulator 15, and a suction circuit 13.

[0046] The refrigeration cycle device 200 can use, for example, R454C, which is the refrigerant used in the above-mentioned embodiment 1. The refrigeration cycle device 200 includes Figure 1 to Figure 3 Therefore, the sliding portion 9 ( Figure 1 ) has high sliding properties, which can improve the reliability of the refrigeration cycle device 200.

[0047] Description of Reference Numerals

[0048] 1 airtight container

[0049] 100 compressors

[0050] 11Indoor heat exchanger

[0051] 200 Refrigeration cycle device

[0052] 21 Fixed scroll

[0053] 22 turns vortex

[0054] 26 Outdoor heat exchanger

[0055] 4 Crankshaft

[0056] 41 Surface

[0057] 42 Film

[0058] 4a Spindle

[0059] 5 Main bearing

[0060] 6Slewing bearing

[0061] 8Compression mechanism

[0062] 9 Sliding part.

Claims

1. A compressor, characterized in that: have: A high-pressure chamber type sealed container enclosing refrigeration oil and a refrigerant containing 50% by mass or more of a hydrofluoroolefin refrigerant; and A compression mechanism part is housed in the sealed container and has a sliding part made of an iron-based material. The refrigeration oil contains at least one of polyvinyl ether and polyol ester. The kinematic viscosity of the refrigeration oil at 40°C is 10 mm 2 / s or more and 40mm 2 / s or less.

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

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

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 In the sliding portion, a film containing fluorine derived from the hydrofluoroolefin refrigerant is formed on a surface of the member formed of the iron-based material.

6. A refrigeration cycle device, characterized in that: It has a compressor, a condenser, an expansion mechanism and an evaporator. The compressor comprises: A high-pressure chamber type sealed container enclosing refrigeration oil and a refrigerant containing 50% by mass or more of a hydrofluoroolefin refrigerant; and A compression mechanism part is housed in the sealed container and has a sliding part made of an iron-based material. The refrigeration oil contains at least one of polyvinyl ether and polyol ester. The kinematic viscosity of the refrigeration oil at 40°C is 10 mm 2 / s or more and 40mm 2 / s or less.

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