Compressor and refrigeration cycle device

Abstract

To provide a compressor that can realize both weight reduction and reliability, and a refrigeration cycle device that comprises the compressor.SOLUTION: A compressor according to an embodiment comprises a compression mechanism part for compressing a refrigerant, and an electric motor part for driving the compression mechanism part. The compression mechanism part comprises a first member comprising a first sliding surface, and a second member comprising a second sliding surface for sliding on the first sliding surface when it is driven by the electric motor part. At least one of the first member and the second member is formed of a resin material. At least one of the first sliding surface and the second sliding surface is subjected to surface treatment for increasing hardness. In addition, compressive strength of the resin material is equal to or higher than contact surface pressure between the first sliding surface and the second sliding surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a compressor and a refrigeration cycle device. [Background technology]

[0002] In recent years, there has been an increasing demand for refrigerants with low GWP (global warming potential) used in refrigeration cycles. Many refrigerants with low GWP have low capacity per volumetric flow rate, so when using such refrigerants, it becomes necessary to increase the displacement volume of the compressor or to increase the rotation speed of the compressor.

[0003] In rotary compressors used in many small air conditioners and some large air conditioners, a roller fitted to a rotating shaft rotates eccentrically in a cylinder chamber. Therefore, when increasing the displacement volume, various problems may occur, such as insufficient rigidity of the rotating shaft due to the increased eccentricity, worsening vibration, and even increased manufacturing costs due to the larger balancer installed on the rotor. One solution to these problems is to reduce the weight of the components that make up the compression mechanism.

[0004] Conventionally, the sliding members in a compressor during operation are made of metal. For example, in a rotary compressor, the rollers and the vanes that slide against the outer circumferential surfaces of the rollers are made of iron-based materials such as cast iron, such as molybdenum-chromium cast iron (cast iron containing molybdenum, nickel, and chromium), and high-speed tool steel.

[0005] In recent years, for example, Patent Document 1 has proposed molding components such as rollers and vanes with Al-Si (aluminum-silicon) alloy castings in order to reduce their weight. However, the specific gravity of Al-Si alloy castings is generally about 2.6 to 3.0, and although it can be made lighter than conventional iron-based materials, it is difficult to make them lighter. That is, in order to reduce the weight, it is necessary to increase the amount of Si added, which has a specific gravity of 1.0 or less, for example. However, adding a large amount of Si increases the size of the primary Si crystals, which increases the amount of dispersion, resulting in a decrease in high-temperature strength due to stress concentration (see Patent Document 2, for example). In practice, the amount of Si added is limited to 19 wt%. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6028832 [Patent Document 2] Japanese Patent Application Publication No. 8-134578 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a compressor that is both lightweight and reliable, and a refrigeration cycle apparatus including the compressor. [Means for solving the problem]

[0008] A compressor according to one embodiment includes a compression mechanism that compresses a refrigerant, and an electric motor that drives the compression mechanism. a cylinder forming a cylinder chamber; a rotating shaft having an eccentric portion disposed within the cylinder chamber; a cylindrical roller fitted to the eccentric portion and rotating eccentrically about a rotation center of the rotating shaft within the cylinder chamber; and a vane having a tip surface that slides against an outer circumferential surface of the roller and dividing the cylinder chamber into a suction chamber and a compression chamber. It is equipped with: The roller teeth, Phenolic resin with carbon fiber It is formed by: The vane is made of a metal material. The resin material has a surface treatment for increasing hardness. Furthermore, the compressive strength of the resin material is equal to or greater than the contact pressure between the first sliding surface and the second sliding surface.

[0009] The refrigeration cycle device of one embodiment includes the compressor, a condenser connected to the compressor, an expansion device connected to the condenser, and an evaporator connected to the expansion device. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a compressor and a refrigeration cycle device according to one embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a compression mechanism included in the compressor according to one embodiment. [Diagram 3] FIG. 3 is a diagram showing an outline of the block-on-ring evaluation test. [Figure 4] FIG. 4 is a table showing the temperature conditions of the refrigeration cycle assumed in the block-on-ring evaluation test. [Diagram 5] FIG. 5 is a table showing the combinations of block materials, ring materials, and refrigerants used in the block-on-ring evaluation test. [Figure 6] FIG. 6 is a graph showing the results of measuring the amount of wear of the block material and the ring material in each sample shown in FIG. [Figure 7] FIG. 7 is a diagram for explaining parameters used in calculating the contact pressure. [Figure 8] FIG. 8 is a table showing the discharge pressure, suction pressure, discharge saturation temperature, suction saturation temperature, block face pressure differential, block face pressure increase rate, and contact face pressure increase rate for a number of refrigerants. [Figure 9] FIG. 9 is a graph showing the results of predicting the amount of wear for each combination of refrigerants based on the rate of increase in contact surface pressure shown in FIG. [Figure 10] FIG. 10 is a graph showing other results of predicting the amount of wear for each combination of refrigerants based on the increase rate of the contact surface pressure shown in FIG. [Figure 11] FIG. 11 is a diagram illustrating an example of a compression mechanism according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment will be described with reference to the drawings. In this embodiment, a rotary compressor, which is an example of a compressor, and a refrigeration cycle device including the compressor are disclosed. However, the configuration according to the present invention can be applied to other types of compressors. The refrigeration cycle device is, for example, an air conditioner, but may be other types of devices.

[0012] 1 is a diagram showing a schematic configuration of a compressor 1 and a refrigeration cycle device 100 according to this embodiment. The compressor 1 includes a compressor body 2, an accumulator 3, and a pair of suction pipes 4 connecting the compressor body 2 and the accumulator 3.

[0013] The refrigeration cycle apparatus 100 includes, in addition to the compressor 1, a first heat exchanger 101 (heat radiator), a second heat exchanger 102 (heat absorber), and an expansion device 103. The first heat exchanger 101 is connected to the discharge port of the compressor body 2 via piping. The second heat exchanger 102 is connected to the accumulator 3 via piping. The expansion device 103 is connected to the first heat exchanger 101 and the second heat exchanger 102 via piping.

[0014] A refrigerant circulates in the refrigeration cycle of the refrigeration cycle device 100 configured as described above. The refrigerant is, for example, R1234yf alone or a refrigerant containing R1234yf as the main component. An example of a refrigerant containing R1234yf as the main component is a mixed refrigerant of R1234yf and R32. The "main component" of a refrigerant refers to the component contained in the refrigerant in the largest amount by mass ratio.

[0015] The refrigerant supplied to the compressor 1 is separated into gas and liquid in the accumulator 3, and the gas refrigerant is guided to the compressor body 2 via each suction pipe 4. The compressor body 2 compresses the gas refrigerant. The compressed high-pressure gas refrigerant is condensed in the first heat exchanger 101. The refrigerant is then decompressed in the expansion device 103, evaporated in the second heat exchanger 102, and supplied to the accumulator 3 again.

[0016] The configuration of the refrigeration cycle apparatus 100 is not limited to that shown in the figure. For example, the refrigeration cycle apparatus 100 may further include a four-way valve that switches the supply destination of the refrigerant discharged from the compressor 1 between the first heat exchanger 101 and the second heat exchanger 102, and switches the supply source of the refrigerant to the accumulator 3 between the first heat exchanger 101 and the second heat exchanger 102.

[0017] The compressor body 2 has a cylindrical sealed container 5. Refrigeration oil is stored in the lower part of the sealed container 5. Furthermore, the sealed container 5 contains an electric motor unit 6 located on the upper side and a compression mechanism unit 7 located on the lower side. The electric motor unit 6 and the compression mechanism unit 7 are connected via a rotating shaft 8.

[0018] The electric motor unit 6 includes a rotor 60 fixed to a rotating shaft 8, and a stator 61 surrounding the rotor 60. A permanent magnet is provided in the rotor 60, and a coil is wound around the stator 61. The stator 61 is fixed to the sealed container 5. As the rotor 60 rotates, the rotating shaft 8 rotates about a center line AX. Hereinafter, the direction parallel to the center line AX will be referred to as the axial direction DX.

[0019] The compression mechanism 7 includes a first cylinder 11 and a second cylinder 12 aligned along the rotary shaft 8, and a partition plate 13 disposed between these cylinders 11, 12. The first cylinder 11 is located between the second cylinder 12 and the electric motor unit 6 in the axial direction DX. In the example of FIG. 1, the partition plate 13 is composed of a first partition plate 131 and a second partition plate 132 aligned in the axial direction DX. However, the partition plate 13 may be composed of a single continuous member.

[0020] A first bearing 14 (main bearing) that rotatably holds the rotating shaft 8 is fixed to an upper end surface of the first cylinder 11. A second bearing 15 (sub-bearing) that rotatably holds the rotating shaft 8 is fixed to a lower end surface of the second cylinder 12.

[0021] The rotating shaft 8 penetrates the first cylinder 11, the second cylinder 12, and the partition plate 13. The rotating shaft 8 has a first eccentric portion 81 and a second eccentric portion 82 that are provided with a phase difference of 180°. The first eccentric portion 81 is fitted into a cylindrical first roller 16. The second eccentric portion 82 is fitted into a cylindrical second roller 17.

[0022] A first cylinder chamber R1 is formed inside the first cylinder 11. The first cylinder chamber R1 corresponds to a space surrounded by the inner circumferential surface of the first cylinder 11, the lower surface of the first bearing 14, and the upper surface of the first partition plate 131. The first eccentric portion 81 and the first roller 16 are located in the first cylinder chamber R1.

[0023] A second cylinder chamber R2 is formed inside the second cylinder 12. The second cylinder chamber R2 corresponds to a space surrounded by the inner circumferential surface of the second cylinder 12, the upper surface of the second bearing 15, and the lower surface of the second partition plate 132. The second eccentric portion 82 and the second roller 17 are located in the second cylinder chamber R2.

[0024] When the rotating shaft 8 rotates, in the first cylinder chamber R1, the first roller 16 rotates eccentrically about the center line AX with the outer circumferential surface of the first roller 16 in line contact with the inner circumferential surface of the first cylinder 11. Similarly, when the rotating shaft 8 rotates, in the second cylinder chamber R2, the second roller 17 rotates eccentrically about the center line AX with the outer circumferential surface of the second roller 17 in line contact with the inner circumferential surface of the second cylinder 12.

[0025] The first bearing 14 is provided with a first discharge valve mechanism 18. For example, the first discharge valve mechanism 18 has a discharge port formed in the first bearing 14, a reed valve for opening and closing the discharge port, and a stopper for regulating the maximum opening degree of the reed valve. The first discharge valve mechanism 18 is covered by a first muffler 19 attached to the first bearing 14. The first muffler 19 has an opening through which the inside and outside of the first muffler 19 communicate with each other.

[0026] The second bearing 15 is provided with a second discharge valve mechanism 20. For example, the second discharge valve mechanism 20 has a discharge port formed in the second bearing 15, a reed valve for opening and closing the discharge port, and a stopper for regulating the maximum opening degree of the reed valve. The second discharge valve mechanism 20 is covered by a second muffler 21 attached to the second bearing 15. Although not shown in the cross section of FIG. 1, the space in the second muffler 21 and the space in the first muffler 19 are in communication with each other through a refrigerant passage that passes through the second bearing 15, the second cylinder 12, the partition plate 13, the first cylinder 11, and the first bearing 14 in this order.

[0027] The first cylinder 11 and the second cylinder 12 are fixed to the sealed container 5. The first cylinder 11, the second cylinder 12, the partition plate 13, the first bearing 14, the second bearing 15, the first muffler 19, and the second muffler 21 are connected together, for example, by a plurality of long bolts BT (only one is shown in FIG. 1) in the axial direction DX.

[0028] The accumulator 3 has a case 30. The gas refrigerant vaporized in the second heat exchanger 102 flows into the case 30 through piping together with the liquid refrigerant. One end of each suction pipe 4 is located at the upper part of the case 30, and the gas refrigerant in the case 30 flows into the suction pipe 4 through these ends. The other end of each suction pipe 4 extends from the lower end side of the case 30 and is connected to the first cylinder 11 and the second cylinder 12, respectively.

[0029] 2 is a schematic cross-sectional view of the compression mechanism 7 at the position of the first cylinder 11. In the example of this figure, a vane slot 110 communicating with the first cylinder chamber R1 is formed in the first cylinder 11. The vane slot 110 extends in the radial direction of the first cylinder chamber R1.

[0030] A vane 22 is inserted into the vane slot 110 so as to be movable radially in the first cylinder chamber R1. The vane 22 is constantly biased toward the first cylinder chamber R1 by a biasing member 23, which is, for example, a coil spring. The vane 22 extends in the axial direction DX with a cross-sectional shape shown in FIG. 2. A tip surface SFa of the vane 22 is in slidable contact with an outer peripheral surface SFb of the first roller 16.

[0031] The first cylinder chamber R1 is divided into a suction chamber Ra and a compression chamber Rb by the vane 22. A suction passage 111 that communicates with the suction chamber Ra is formed in the first cylinder 11. Gas refrigerant is supplied from the suction passage 111 through the suction pipe 4 described above. When the rotating shaft 8 rotates, the volumes of the suction chamber Ra and the compression chamber Rb change in accordance with the eccentric rotation of the first eccentric portion 81 and the first roller 16. This causes the gas refrigerant to be compressed. The compressed gas refrigerant is discharged from the compression chamber Rb through the first discharge valve mechanism 18 described above into the space surrounded by the first muffler 19.

[0032] 2, a plurality of bolt holes H for passing the above-mentioned bolts BT therethrough are provided in the first cylinder 11. Although omitted in FIG. 2, the first cylinder 11 may also have communication holes that constitute the above-mentioned refrigerant passages that communicate between the space in the second muffler 21 and the space in the first muffler 19.

[0033] The cross-sectional structure of the compression mechanism 7 at the position of the second cylinder 12 is similar to that shown in Fig. 2. That is, the second cylinder 12 is also provided with a vane slot 110 and a suction passage 111, and the vane 22 and the biasing member 23 are housed in the vane slot 110. Then, gas refrigerant sucked from the suction pipe 4 is supplied to the suction chamber Ra through the suction passage 111, and is compressed in association with the eccentric rotation of the second eccentric portion 82 and the second roller 17. The compressed gas refrigerant is discharged from the compression chamber Rb via the above-mentioned second discharge valve mechanism 20 into the space surrounded by the second muffler 21.

[0034] In a typical rotary compressor, the rollers and vanes are formed from metal materials such as SUS440C, a martensitic stainless steel, SKH51, a high-speed tool steel, or Ni-Cr-Mo (nickel, chromium, molybdenum)-based flaky graphite cast iron, called Monichrome cast iron.

[0035] In contrast, in the compressor 1 according to this embodiment, at least one of the first roller 16, the second roller 17, and each of the vanes 22 that slide with these rollers 16, 17 is made of a resin material. Specifically, the first roller 16 and the second roller 17 are made of a resin material, and each of the vanes 22 is made of a metal material.

[0036] The resin material forming the first roller 16 and the second roller 17 has a compressive strength equal to or greater than the contact surface pressure between the outer circumferential surfaces SFb of these rollers 16, 17 and the tip surfaces SFa of the vanes 22. Furthermore, at least the tip surfaces SFa of each vane 22 are subjected to a surface treatment to increase the hardness.

[0037] In one example, the above-mentioned contact pressure is a Hertzian contact pressure calculated based on Hertz's contact theory, with the maximum value being the difference between the design pressure of the refrigerant in compressor 1 or a refrigeration cycle including compressor 1 (e.g., the pressure at a reference condensing temperature of 65°C) and atmospheric pressure. Here, the design pressure is in accordance with, for example, the exemplary standards related to the refrigeration safety regulations.

[0038] It is preferable to use a thermosetting resin material, and among them, phenolic resin is suitable, as the resin material forming the first roller 16 and the second roller 17. Thermosetting resin materials such as phenolic resin have a higher glass transition temperature than thermoplastic resin materials such as PEEK and PBT, and exhibit good mechanical properties even when the inside of the sealed container 5 becomes hot.

[0039] For example, SUS440C or SKH51 can be used as the metal material forming each vane 22. For surface treatment applied to these metal materials, for example, DLC (diamond-like carbon) treatment, which forms a hard carbon film on the metal surface, or nitriding treatment can be used.

[0040] The resin material forming the first roller 16 and the second roller 17 preferably contains reinforcing fibers such as glass fiber and carbon fiber. This increases the compressive strength of the resin material. Furthermore, the linear expansion coefficient of the resin material can be reduced, so that deformation of the first roller 16 and the second roller 17 can be suppressed even when the temperature inside the sealed container 5 becomes high.

[0041] The following describes an evaluation test of the compressor 1 using a resin material, the compressive strength of the resin material, and the applicable range of refrigerants.

[0042] [Evaluation test] The amount of wear was evaluated by performing a block-on-ring evaluation test on a number of combinations of the materials of the first roller 16 and the second roller 17 and the material of the vane 22 .

[0043] Fig. 3 is a diagram showing an outline of the block-on-ring evaluation test. In this block-on-ring evaluation test, a block material BL simulating the vane 22 and a ring material RN simulating the first roller 16 and the second roller 17 were used. The ring material RN rotates around an axis AX0. Fig. 3(a) is a plan view of the block material BL and the ring material RN seen in a direction parallel to the axis AX0, and Fig. 3(b) is a side view of the block material BL and the ring material RN.

[0044] In the evaluation test, a load W was applied from the back surface of the block material BL, and the sliding surface SF1 of the block material BL was pressed against the sliding surface SF2 (outer peripheral surface) of the ring material RN. This state was maintained for a predetermined time, and the amount of wear of the block material BL and the ring material RN was measured.

[0045] During the test, the evaluation test machine in which the block material BL and the ring material RN were placed was filled with refrigeration oil and refrigerant, and heated to an appropriate test temperature. Ester oil was used as the refrigeration oil. R410A and R1234yf were used as the refrigerants.

[0046] Figure 4 is a table showing the temperature conditions of the refrigeration cycle assumed in the evaluation test. In both cases where R410A and R1234yf are used as refrigerants, the condensation temperature is 50°C, the evaporation temperature is 0°C, the degree of heating (SH) is 5K, the amount of subcooling (SC) is 8K, and the adiabatic compression efficiency is 70%.

[0047] The discharge temperature of the compressor 1 is 89° C. in the case of R410A, and 60° C. in the case of R1234yf. The test temperatures were set by adding about 10 K to these discharge temperatures, that is, 100° C. for R410A and 70° C. for R1234yf.

[0048] In the rotary compressor 1, the back pressure of the vane 22 is high (discharge pressure), and the inside of the compression chamber Rb is low (suction pressure). Due to the pressure difference between the discharge pressure and the suction pressure, the vane 22 is pressed against the first roller 16 and the second roller 17, respectively, and the rollers 16, 17 and the vane 22 are in close contact with each other.

[0049] In such a structure, the contact surface pressure at the contact portion between the rollers 16, 17 and each vane 22 depends on the pressure of the refrigerant. Therefore, the load W [N] (block surface pressure) in the block-on-ring evaluation test was set to 650 N when R410A was used as the refrigerant, and 280 N when R1234yf was used as the refrigerant.

[0050] 5 is a table showing the combinations of block materials BL, ring materials RN, and refrigerants used in the block-on-ring evaluation test. The evaluation test was carried out for nine samples SP1 to SP9.

[0051] Samples SP1 and SP2 are comparative examples of this embodiment, and both are assumed to use R410A as a refrigerant. In sample SP1, the block material BL is made of SUS440C that has been subjected to nitriding treatment as a surface treatment, and the ring material RN is made of mono-chrome cast iron. In sample SP2, the block material BL is made of SKH51 that has been subjected to DLC treatment as a surface treatment, and the ring material RN is made of mono-chrome cast iron.

[0052] In samples SP3 to SP9, assuming the use of R1234yf as the refrigerant, one of the block material BL and the ring material RN was made of a non-metallic material. In sample SP3, the block material BL was made of resin A, and the ring material RN was made of monochromatic cast iron. Resin A was a phenolic resin containing glass fiber as a reinforcing fiber.

[0053] In sample SP4, the block material BL is made of SUS440C that has been subjected to nitriding treatment, and the ring material RN is made of resin A. In sample SP5, the block material BL is made of SKH51 that has been subjected to DLC treatment, and the ring material RN is made of resin A.

[0054] In sample SP6, the block material BL is made of SUS440C that has been subjected to nitriding treatment, and the ring material RN is made of resin B. In sample SP7, the block material BL is made of SKH51 that has been subjected to DLC treatment, and the ring material RN is made of resin B. Resin B is a phenolic resin containing carbon fiber as a reinforcing fiber.

[0055] In sample SP8, the block material BL is made of SUS440C that has been subjected to nitriding treatment, and the ring material RN is made of carbon. In sample SP9, the block material BL is made of SKH51 that has been subjected to DLC treatment, and the ring material RN is made of carbon. These carbons are formed by processing carbon graphite materials.

[0056] Fig. 6 is a graph showing the results of measuring the amount of wear [μm] of the block material BL and the ring material RN in samples SP1 to SP9. Samples SP1 and SP2 are combinations of roller and vane materials and refrigerant (R410A) that have been conventionally used. In other words, samples SP1 and SP2 serve as the standard amount of wear. The standard amount of wear in the measurement results is approximately 0.7 to 0.9 μm for the block material BL and approximately 0.4 to 0.6 μm for the ring material RN.

[0057] In sample SP3, the amount of wear of the block material BL is significantly increased by more than five times compared to samples SP1 and SP2. Therefore, it is found that when the first roller 16 and the second roller 17 are made of monochromatic cast iron, the vane 22 should not be made of resin A.

[0058] In samples SP4 and SP5, in which the ring material RN is formed from resin A, the amount of wear of the block material BL is suppressed compared to sample SP3. However, in sample SP4, the amount of wear of the block material BL is about three times higher than in samples SP1 and SP2, although not as much as in sample SP3. In sample SP4, the amount of wear of the ring material RN is smaller than the amount of wear of the block material BL. In sample SP5, the amount of wear of the block material BL is smaller than in samples SP1 and SP2, and the amount of wear of the ring material RN is equivalent to that of samples SP1 and SP2.

[0059] The reason why the amount of wear of sample SP4 was larger than that of sample SP5 is thought to be that the sliding between the block material BL and the ring material RN exposed glass fibers on the sliding surface SF2 of the ring material RN, and these glass fibers damaged the sliding surface SF1 of the block material BL. In addition, the hardness of the nitrided SUS440C was about 1000HV0.1, while the hardness of the DLC-treated SKH51 was about 2000HV0.1, and it is thought that the results of sample SP5 were superior due to the difference in hardness.

[0060] In samples SP6 and 7 in which the ring material RN was made of resin B, good results were obtained in both the wear amount of the block material BL and the wear amount of the ring material RN, regardless of the material of the block material BL. However, over time, carbon fiber may be exposed on the sliding surface SF2 of the ring material RN and damage the sliding surface SF1 of the block material BL. From this point of view, it is preferable to form the block material BL from high-strength SKH51 treated with DLC.

[0061] In both samples SP8 and SP9, the amount of wear of the ring material RN was significantly increased compared to samples SP1 and SP2. Since the strength of the ring material RN may be insufficient if carbon is used alone, it is understood that the first roller 16 and the second roller 17 should not be formed of carbon alone.

[0062] From the above results of the block-on-ring evaluation test, it is found that if one of the block material BL and the ring material RN, i.e., one of the vane 22 and the rollers 16, 17, is made of resin and a surface treatment that increases hardness is applied to the tip surface SFa of the vane 22 or the outer peripheral surface SFb of the rollers 16, 17, it is possible to suppress the amount of wear and ensure the reliability of the compressor 1. In particular, based on the results of samples SP5 and SP7, it is preferable that DLC treatment is applied as the surface treatment.

[0063] Resin A containing glass fiber has high isotropy, whereas Resin B containing carbon fiber has higher anisotropy than Resin A. Considering the mechanical properties of Resins A and B, it is preferable to use Resin A rather than Resin B.

[0064] [Compressive strength of resin material] As described above, the resin material forming the first roller 16 and the second roller 17 has a compressive strength equal to or greater than the contact surface pressure between the tip surface SFa of the vane 22 and the outer circumferential surfaces SFb of these rollers 16, 17. This can further improve the reliability of the compressor 1. Both of the above-mentioned resins A and B have a compressive strength of 300 MPa or more.

[0065] In the rotary compressor 1, the tip surface SFa of the vane 22 comes into contact with the outer circumferential surfaces SFb of the rollers 16 and 17, which are cylindrical surfaces, and therefore the contact surface pressure therebetween can be calculated based on the Hertz contact theory.

[0066] Fig. 7 is a diagram for explaining the parameters used in calculating the contact pressure. Here, the parameters are illustrated by taking the block material BL and the ring material RN used in the block-on-ring evaluation test as models of the vane 22 and the rollers 16, 17, respectively. (a) in Fig. 7 shows a part of the cross section of the block material BL and the ring material RN as viewed parallel to the axis of rotation of the ring material RN (AX0 mentioned above), and (b) shows the cross section of the block material BL and the ring material RN parallel to that axis.

[0067] "D" in (a) of Fig. 7 is the width of the block material BL, "2b" is the contact width [m] of the sliding surfaces SF1 and SF2, and "W" is the load [N] acting on the back surface of the block material BL. "L" in (b) of Fig. 7 is the contact length [m] of the sliding surfaces SF1 and SF2 in the direction parallel to the axis of the ring material RN.

[0068] The half-value b [m] of the contact width can be expressed by the following formula using the equivalent radius of curvature R and the equivalent Young's modulus E'.

number

[0069] The equivalent radius of curvature R is the radius of curvature R of the sliding surface SF1. 1 and the radius of curvature R of the sliding surface SF2 2 is given by the following formula:

number

[0070] The reciprocal of the equivalent Young's modulus E' is given by the following equation:

number

[0071] Maximum contact pressure P of sliding surfaces SF1 and SF2 max [N / m 2 = Pa] and the average contact pressure P mean [N / m 2 =Pa] is given by the following formula:

number

[0072] By rearranging the above equation, the following equation is obtained.

number

[0073] The Hertzian contact pressure (P max ), the resin material for the ring material RN, i.e., the resin material used for the first roller 16 and the second roller 17, is selected. The resin material may be selected so as to have a compressive strength greater than a value obtained by multiplying the contact pressure by a predetermined coefficient (e.g., 2). Since the strength of a resin material is temperature dependent, the resin material may be selected so that the compressive strength according to the temperature (e.g., compressive strength at 140°C) is greater than the contact pressure.

[0074] Each parameter used in the calculation of the Hertzian contact pressure can be applied as a parameter of the component of the compressor 1. That is, "D" corresponds to the width of the vane 22, "2b" corresponds to the contact width between the tip surface SFa and the outer peripheral surface SFb, "W" corresponds to the load acting on the back surface of the vane 22, "L" corresponds to the contact length between the tip surface SFa and the outer peripheral surface SFb in the axial direction DX, and "R 1 " corresponds to the radius of curvature of the tip surface SFa, and "R 2 " corresponds to the radius of curvature of the outer peripheral surface SFb, and "E 1 " corresponds to the Young's modulus of the vane 22, and "E 2 " corresponds to the Young's modulus of the rollers 16 and 17, and "ν 1 " corresponds to the Poisson's ratio of the vane 22, and "ν 2 " corresponds to the Poisson's ratio of rollers 16 and 17, and "P max " corresponds to the maximum value of the contact pressure between the tip surface SFa and the outer peripheral surface SFb, and "P mean " corresponds to the average contact pressure between the tip surface SFa and the outer peripheral surface SFb.

[0075] [Applicable range of refrigerant] In the above-mentioned block-on-ring evaluation test, it was assumed that R410A or R1234yf was used alone as a refrigerant. R1234yf is generally mixed with R32 and is mainly used as a refrigerant for air conditioners, chilling units, or freezers. R1234yf is low pressure and R32 is high pressure, so the pressure of these mixed refrigerants is in the range between R1234yf and R32. Depending on the mixing ratio, the amount of wear of the rollers 16, 17 and the vane 22 does not increase much, so they can be used as the refrigerant for the compressor 1 according to this embodiment.

[0076] A method for predicting the amount of wear when the refrigerant is changed will be described below. Generally, the amount of wear can be calculated using the specific wear rate. The unit of the amount of wear is [mm], and the unit of the specific wear rate is [mm 3 / (N m)]. Therefore, as shown in the following formula, the contact pressure P [N / mm 2], sliding speed V [m / S], and sliding time T [S] are multiplied by the specific wear amount K to calculate the wear amount X [mm].

number

[0077] In the block-on-ring evaluation test, the specific wear rate K, contact pressure P, sliding speed V, and sliding time T are known values. The specific wear rate K can be calculated from the results of the above evaluation test assuming R1234yf as the refrigerant, and the value can be treated as a fixed value. In addition, the sliding speed V and sliding time T are test parameters in the block-on-ring evaluation test and are fixed values.

[0078] That is, the amount of wear when the refrigerant is changed can be predicted by calculating the rate of change in the contact pressure P that accompanies the change in refrigerant. Specifically, the amount of wear X when the composition ratio of a mixed refrigerant of R1234yf and R32 is changed can be predicted simply by calculating the rate of increase in the contact pressure P of the block material BL and the ring material RN in a block-on-ring evaluation test.

[0079] As mentioned above, the maximum contact pressure P max and the average contact pressure P mean is given by the following equation:

number

[0080] Equivalent radius of curvature R, Young's modulus E 1 ,E 2 , Poisson's ratio ν 1 ,ν 2 and contact length L are test parameters or material-specific parameters in block-on-ring evaluation tests, and are fixed values. In other words, when calculating the contact pressure P between the block material BL and the ring material RN, all the values ​​except for the load W can be treated as fixed values ​​regardless of the type of refrigerant.

[0081] The load W is the surface load applied to the back surface of the block material BL and is given by the following formula:

number

[0082] Figure 8 is a table showing the discharge pressure, suction pressure, discharge saturation temperature, suction saturation temperature, block face pressure differential, block face pressure increase rate, and contact face pressure increase rate for multiple refrigerants. Here, R1234yf, R454C, R454A, R454B, and R32 are shown as examples of refrigerants. The block face pressure increase rates for R454C, R454A, R454B, and R32 are based on R1234yf.

[0083] The discharge pressure and suction pressure of R454C, R454A, R454B, and R32 are set so that the discharge saturation temperature and suction saturation temperature of these refrigerants are equivalent to those of R1234yf. Specifically, since a temperature glide occurs when mixing refrigerants, the discharge pressure and suction pressure of each refrigerant are set so that the average value of the saturation temperature at quality fraction 1 and quality fraction 0 for each discharge saturation temperature and suction saturation temperature is equivalent to that of R1234yf.

[0084] The discharge pressure (design pressure) of R1234yf, 1.73MPa_G, is the pressure at which a saturation temperature equal to 64.9°C is obtained, which is the saturation temperature corresponding to the design pressure of 4.17MPa_G that is generally used in compressors for R410A.

[0085] R434C, R454A, and R454B are all mixed refrigerants of R1234yf and R32. However, because the composition ratios of these mixed refrigerants are different, their GWPs and pressures are also different.

[0086] Fig. 9 is a graph showing the results of predicting the amount of wear for the combination of the above-mentioned sample SP5 and each refrigerant, based on the increase rate of contact pressure etc. shown in Fig. 8. Fig. 10 is a graph showing the results of predicting the amount of wear for the combination of the above-mentioned sample SP7 and each refrigerant, based on the increase rate of contact pressure etc. shown in Fig. 8.

[0087] 9 and 10, the standard 1 is the amount of wear when R410A is used as the refrigerant like sample SP1, the block material BL is nitrided, and the ring material RN is made of monochromatic cast iron. Also, the standard 2 is the amount of wear when R410A is used as the refrigerant like sample SP2, the block material BL is DLC-treated, and the ring material RN is made of monochromatic cast iron. As a result of predicting the amount of wear, the amount of wear of the block material BL of standards 1 and 2 is about 0.7 to 0.9 μm, and the amount of wear of the ring material RN is about 0.5 μm.

[0088] 9 and 10, it can be seen that the amount of wear does not increase significantly compared to R1234yf for any of the mixed refrigerants (R454C, R454A, R454B). For this reason, the configuration in which the first roller 16 and the second roller 17 are made of a resin material as in the compressor 1 according to this embodiment can be applied not only to a single refrigerant R1234yf, but also to a mixed refrigerant of R1234yf and R32.

[0089] In the compressor 1 according to the present embodiment described above, some of the members constituting the compression mechanism 7 are made of a resin material, which reduces the weight of the compression mechanism 7. As a result, even if the eccentricity of the first roller 16 and the second roller 17 is increased, the rigidity of the rotating shaft 8 is unlikely to be insufficient and vibration is unlikely to be aggravated.

[0090] Even if the first roller 16 and the second roller 17 are made of Al-Si alloy casting, which is a lightweight metal material, the specific gravity is about 2.6 to 3.0. In contrast, if the first roller 16 and the second roller 17 are made of a resin material, the specific gravity can be suppressed to 2.0 or less.

[0091] Furthermore, in this embodiment, the resin material from which the rollers 16, 17 are made has a compressive strength equal to or greater than the contact surface pressure with the vane 22, and the tip surface SFa of the vane 22 is subjected to a surface treatment such as DLC treatment or nitriding treatment. This makes it possible to suppress the amount of wear of the rollers 16, 17 and the vane 22, and to improve the reliability of the compressor 1. In addition to the above, various other advantageous effects can be obtained from this embodiment.

[0092] In this embodiment, the vane 22 is an example of a first member, and the first roller 16 and the second roller 17 are an example of a second member. The tip surface SFa of the vane 22 is an example of a first sliding surface, and the outer circumferential surfaces SFb of the first roller 16 and the second roller 17 are an example of a second sliding surface.

[0093] In the present embodiment, the rollers 16, 17 are formed of a resin material, and the vane 22 is formed of a metal material. As another example, the rollers 16, 17 may be formed of a surface-treated metal material, and the vane 22 may be formed of a resin material. In this case, the first roller 16 and the second roller 17 are an example of the first member, and the vane 22 is an example of the second member. In addition, both the rollers 16, 17 and the vane 22 may be formed of a resin material. In this case, if the surface of at least one of the rollers 16, 17 and the vane 22 is subjected to a surface treatment such as DLC treatment, welding of the rollers 16, 17 and the vane 22 due to heat during sliding can be suppressed.

[0094] In the present embodiment, the rotary compressor 1 is illustrated as having two cylinders 11 and 12. As another example, the compressor 1 may have only one cylinder, or three or more cylinders.

[0095] The sliding mechanism including the first member and the second member can be applied not only to the rollers 16, 17 and the vane 22 of the rotary compressor 1 but also to the sliding mechanism of other types of compressors, such as a swing rotary compressor.

[0096] 11 is a diagram showing an example of a compression mechanism 200 (slide mechanism) provided in a swing rotary compressor. The compression mechanism 200 includes a cylinder 210 and a piston 220.

[0097] The cylinder 210 has a cylinder chamber Rm, a slot 211, and a refrigerant suction passage 212. An eccentric portion 230 of a rotating shaft driven by an electric motor unit is disposed in the cylinder chamber Rm.

[0098] The piston 220 has a cylindrical roller 221 in which the eccentric portion 230 is fitted, and a blade 222 that protrudes in the radial direction from the roller 221. The roller 221 and the blade 222 are integrally formed.

[0099] A pair of bushings 240 are disposed in the slot 211. The blade 222 is passed between these bushings 240 in the slot 211. The blade 222 divides the cylinder chamber Rm into a suction chamber Ra and a compression chamber Rb.

[0100] In the compression mechanism 200 configured as above, the blade 222 advances and retreats from the slot 211 in accordance with the eccentric rotation of the eccentric portion 230 and the roller 221, and the volumes of the suction chamber Ra and the compression chamber Rb change. This causes the gas refrigerant to be compressed. During this compression operation, the blade 222 and the bush 240 slide against each other.

[0101] In compression mechanism 200, for example, piston 220 may be made of the same resin material as rollers 16 and 17 in the above-described embodiment, and bush 240 may be made of the same metal material as vane 22 in the above-described embodiment. In this case, bush 240 is an example of a first member, piston 220 is an example of a second member, the surface of bush 240 is an example of a first sliding surface, and the surface of blade 222 is an example of a second sliding surface.

[0102] Also, for example, bush 240 may be made of the same resin material as rollers 16, 17 in the above-described embodiment, and piston 220 may be made of the same metal material as vane 22 in the above-described embodiment. In this case, piston 220 is an example of a first member, bush 240 is an example of a second member, the surface of blade 222 is an example of a first sliding surface, and the surface of bush 240 is an example of a second sliding surface.

[0103] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0104] Reference Signs List 1...compressor, 5...sealed container, 6...motor section, 7...compression mechanism section, 8...rotating shaft, 11, 12...cylinder, 13...partition plate, 14...first bearing, 15...second bearing, 16, 17...roller, 22...vane, 81, 82...eccentric section, 100...refrigeration cycle device, 101...first heat exchanger, 102...second heat exchanger, 103...expansion device.

Claims

1. A compressor including a compression mechanism that compresses a refrigerant and an electric motor that drives the compression mechanism, The compression mechanism includes: A cylinder forming a cylinder chamber; a rotating shaft having an eccentric portion disposed within the cylinder chamber; a cylindrical roller that is fitted to the eccentric portion and rotates eccentrically with respect to the center of rotation of the rotary shaft within the cylinder chamber; a vane having a tip surface that slides against an outer circumferential surface of the roller and that divides the cylinder chamber into a suction chamber and a compression chamber; Equipped with The roller is made of a phenolic resin containing carbon fiber, The vane is formed of a metal material, The tip surface of the vane is subjected to a surface treatment to increase hardness, The compressive strength of the phenolic resin is equal to or greater than the contact surface pressure between the outer circumferential surface of the roller and the tip surface of the vane. Compressor.

2. A compressor comprising a compression mechanism for compressing a refrigerant and an electric motor for driving the compression mechanism, The compression mechanism includes: a cylinder having a cylinder chamber and a slot communicating with the cylinder chamber; a bushing disposed in the slot; a rotating shaft having an eccentric portion disposed within the cylinder chamber; a piston having a cylindrical roller fitted to the eccentric portion and a blade that slides against the bush in the slot in response to the eccentric rotation of the eccentric portion; Equipped with At least one of the bush and the piston is made of a resin material, At least one of the surface of the bush and the surface of the blade is subjected to a surface treatment to increase hardness; a compressive strength of the resin material is equal to or greater than a contact pressure between a surface of the bush and a surface of the blade; Compressor.

3. The contact pressure is a Hertzian contact pressure calculated based on the Hertzian contact theory with a maximum value being a difference between a design pressure of the refrigerant in the compressor or a refrigeration cycle including the compressor and atmospheric pressure. The compressor according to claim 1.

4. The refrigerant is R1234yf alone or a refrigerant containing R1234yf as a main component and at least R32. A compressor according to any one of claims 1 to 3.

5. A compressor according to any one of claims 1 to 4; a condenser connected to the compressor; an expansion device connected to the condenser; an evaporator connected to the expansion device; A refrigeration cycle device comprising:

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