JP5300727B2 - Rotary compressor - Google Patents

Abstract

A natural refrigerant low-pressure shell-type rotary compressor in which the amount of oil contained on the high-pressure side is reduced with sufficient lubrication and sealing performance at a sliding section secured. The compressor has a rotary refrigerant compression mechanism provided in a low-pressure enclosed container and having vanes, an oil separation element for separating lubricating oil from the refrigerant, and an oil supply passage for supplying the separated lubricating oil to a vane back pressure chamber of the compression mechanism, a crankshaft, a bearing, a cylinder, a piston, and oil supply spaces between the vanes. Vane skip is suppressed, and efficient lubrication and high sealing performance at the sliding section and a reduction in the amount of the oil contained on the high-pressure side are achieved at the same time. The compressor is highly reliable, is of low cost, has high performance, and uses a reduced amount of refrigerant.

Description

  The present invention relates to a rotary compressor, and more particularly to a natural refrigerant low-pressure shell type rotary compressor.

Rotary compressors are widely used in refrigerators, air conditioners, heat pump water heaters, and the like because they can be miniaturized and have a simple structure (see Non-Patent Document 1). In recent years, from the viewpoint of preventing global warming, natural refrigerants with a low ozone depletion coefficient and a small global warming coefficient have attracted attention as new refrigerants that can replace CFCs. Carbon (CO ₂ ) refrigerants and hydrocarbon (HC) refrigerants that are flammable but have excellent refrigerant characteristics are expected. Table 1 shows, as a comparison table, operating conditions of a rotary compressor using chlorofluorocarbon refrigerants (R22, R410A), HC refrigerants (isobutane, propane), and CO ₂ refrigerant, and is based on the Ashrae-T condition standard (condensation temperature (CT)). / Evaporation temperature (ET) = 54.4 / 7.2 [° C.] ° C., subcool / super-heat = 8.3 / 27.8 [K]) to compressor suction temperature (Ts) = 35 ° C., expansion The operating conditions of the compressor under the condition of the temperature before the valve (Texp) = 46.1 ° C. are shown.

As shown in Table 1 of FIG. 1, the operating pressure of the compressor using the CO ₂ refrigerant is higher than that of the compressor using the CFC refrigerant. For example, the suction pressure (Ps) of the heat pump water heater is about 4 MPa and the discharge pressure (Pd) is about 10 MPa. For this reason, the conventional rotary compressor has a problem that a large pressing load is applied to the vane that is in pressure contact with the rotating piston that rotates eccentrically in the cylinder and partitions the cylinder into a suction chamber (low pressure) and a compression chamber (low pressure to high pressure). It was. Further, since the sealed container of the high-pressure shell type compressor needs to have strength capable of withstanding the discharge pressure (Ps), there is a problem that the thickness and the weight and cost increase. As a solution, an invention has been proposed in which oil obtained by separating a high-pressure refrigerant with an oil separator is introduced into a vane back pressure chamber in a low-pressure shell-type two-stage rotary compressor (see, for example, Patent Document 1).

  There are three major issues to make a rotary compressor into a low-pressure shell: (1) to suppress vane jumping, (2) to ensure sliding section lubrication performance, and (3) to ensure leakage seal performance. is there.

  Although the problem (1) has been solved by the invention described in Patent Document 1, the problems (2) and (3) have not been solved because of the structure in which the lubricating oil in the low-pressure sealed container is supplied to the compression mechanism.

  On the other hand, hydrocarbons have refrigerant characteristics equivalent to those of chlorofluorocarbon refrigerants from the viewpoint of sliding portion lubrication performance, leakage seal performance, and theoretical refrigeration cycle COP, and can operate at the same pressure as conventional chlorofluorocarbon refrigerants. Refrigerated refrigerators using isobutane have already been mass-produced, but due to the danger of flammable refrigerants, the allowable refrigerant filling amount is limited by international standards (see Non-Patent Document 2). For example, according to the IEC standard, the amount of hydrocarbon refrigerant that can be charged into a home air conditioner is within about 150 kg.

  As a solution to this problem, the use of a low-pressure shell in the sealed container is effective, and the pressure during operation of the refrigerant in the sealed container and the stored lubricating oil is kept low, so that both the amount of refrigerant dissolved in the lubricating oil and the amount of refrigerant not dissolved Can be reduced.

  Patent Document 2 discloses an oil connected to a refrigerant discharge pipe in a rotary compressor that includes a compression mechanism section in a sealed container and discharges the refrigerant compressed by the compression mechanism section to the outside of the sealed container by a refrigerant discharge pipe. The structure which makes the oil return pipe | tube of a separator and an oil separator communicate in an airtight container is disclosed. In this proposal, since there is no means for adjusting the amount of oil stored on the high pressure oil separator side, the amount of refrigerant dissolved in the lubricating oil increases if the amount of oil on the high pressure side increases too much. Therefore, there is a possibility that the effect of reducing the refrigerant filling amount cannot be obtained. On the other hand, if the amount of high-pressure side oil decreases too much, the high-pressure refrigerant is returned to the low-pressure side, and there is a concern that the performance will deteriorate rapidly. From the above, in order to reduce the amount of HC refrigerant charged in the low-pressure shell compressor, (4) means for adjusting the amount of oil stored on the high-pressure side to an appropriate amount is required.

JP 2006-200504 A JP 2004-239204 A Japan Society of Refrigerating and Air Conditioning Engineers, Advanced Standard Text Refrigerating and Air Conditioning Technology: Refrigeration (2000), page 100 Non-Freon Technology: New Trend of Natural Refrigerant (2004), page 172

Therefore, the objects of the present invention are (3) ensuring lubrication performance of sliding parts (bearings, vanes), (3) ensuring sealing performance of rotating pistons and vanes, and (4) reducing the amount of oil stored on the high pressure side. To obtain a low-pressure shell-type rotary compressor using CO ₂ refrigerant or HC refrigerant.

In order to achieve such an object, a rotary compressor of the present invention is connected to an external refrigerant circuit through a suction pipe and a discharge pipe, and includes a sealed container that encloses a low-pressure refrigerant, and an electric motor provided in the sealed container. A low-stage compression mechanism that is provided in the closed container and sucks and compresses low-pressure refrigerant and discharges it at an intermediate pressure; a high-stage compression mechanism that sucks and compresses intermediate-pressure refrigerant and discharges it at a high pressure; A crankshaft connected to an electric motor, and a bearing that supports the crankshaft so that a bearing gap is formed between the crankshaft, and each of the low-stage compression mechanism and the high-stage compression mechanism A rotary piston that is driven by the crankshaft and rotates eccentrically in the cylinder, and a vane that forms a suction chamber and a compression chamber in the cylinder and forms a vane back pressure chamber in the back, and seals the compression chamber. Naga An oil supply gap is formed for sliding, and the high-pressure refrigerant compressed by the high-stage compression mechanism is separated from the oil separated by the oil separation element before being discharged to the external refrigerant circuit. A high-pressure supply path for supplying the vane back pressure chamber of the mechanism, the oil supply gap and the bearing gap excluding the vane back pressure chamber of the high-stage compression mechanism, and the low-stage compression mechanism in the vane back pressure chamber and further comprising a plurality of paper oil path for refueling, the low-stage pressure of the refrigerant in the vane back pressure chamber of the compression mechanism in the vane back pressure chamber of the high-stage compression mechanism A rotary compressor characterized in that a flow path resistance of the oil supply path for guiding lubricating oil to the vane back pressure chamber of the oil separation element and the low-stage compression mechanism is adjusted so as to be lower than the pressure of the refrigerant. It is.

The natural refrigerant (CO ₂ refrigerant and HC refrigerant) low-pressure shell-type rotary compressor having such a configuration includes (1) suppressing vane jump, (2) ensuring lubrication performance of the sliding portion, and (3) sliding. It is possible to satisfy the requirements of securing the sealing performance of the parts and (4) reducing the amount of oil stored on the high pressure side at the same time, and to achieve high reliability, low cost, high performance, and reduction of the refrigerant amount.

CFC refrigerant is a table showing a comparison of the operating conditions of the rotary compressor using the HC refrigerant, CO ₂ refrigerant. It is an assembly figure showing the whole rotary compressor composition concerning Embodiment 1 of this invention. (Embodiment 1) FIG. 2 is a schematic cross-sectional view showing a configuration of a first compression mechanism of the rotary compressor of FIG. 1. (Embodiment 1) FIG. 3 is a cross-sectional view exaggeratingly showing an oil supply gap in the high-stage compression mechanism shown in FIG. 2. (Embodiment 1) FIG. 3 is a longitudinal sectional view exaggeratingly showing an oil supply gap in the high-stage compression mechanism shown in FIG. 2. (Embodiment 1) It is a table | surface which shows the effect of the rotary compressor of this invention at the time of using a propane refrigerant | coolant compared with a prior art. (Embodiment 1) The effect of the rotary compressor of the present invention is a table showing a comparison of the prior art in the case of using CO ₂ refrigerant. (Embodiment 1) It is an assembly figure which shows the whole structure of the rotary compressor which concerns on Embodiment 2 of this invention. (Embodiment 2) It is an assembly figure which shows the whole structure of the rotary compressor which concerns on Embodiment 3 of this invention. (Embodiment 3) It is an assembly figure which shows the whole structure of the rotary compressor which concerns on Embodiment 4 of this invention. (Embodiment 4)

Hereinafter, a plurality of embodiments will be described as an example in which the present invention is applied to a vane type rotary compressor with reference to the accompanying drawings. In the following description, the terms “low pressure”, “intermediate pressure”, and “high pressure” are used. These represent the relative magnitude of the refrigerant pressure, and are absolute values. It does not indicate. “Low pressure”, “intermediate pressure” and “high pressure” represent the pressure before the first stage compression, the pressure after the first stage compression and before the second stage compression, and the pressure after the second stage compression, respectively. Two-stage compressors are roughly classified into three types according to the pressure level in the sealed container. If the pressure in the sealed container (here, it refers to the pressure of the main part of the sealed container; the pressure may be partially different) is equal to the evaporator pressure or the suction pressure of the first compression mechanism. “Low-pressure shell type”, “intermediate-pressure shell type” when equal to the discharge pressure of the first compression mechanism, or suction pressure of the second compression mechanism, and gas cooler (condensation similar to chlorofluorocarbon refrigerant when used below supercriticality) If the pressure is equal to the discharge pressure of the second compression mechanism, it is a “high pressure shell type”.
In the two-stage compressor, the first compression mechanism means a low-stage compression mechanism, and the second compression mechanism means a high-stage compression mechanism.

Embodiment 1

  FIG. 2 is an assembly diagram showing the overall configuration of the low-pressure shell type two-stage rotary compressor according to the first embodiment of the present invention. The rotary compressor of the present invention includes a hermetic container 8, an electric motor 9 provided in the hermetic container 8, a crankshaft 6 driven by the electric motor 9, and a long shaft side bearing 7a that supports both ends of the crankshaft 6. A short shaft side bearing 7 b and first and second compression mechanisms 10 and 20 are provided, and an oil separation element 40 is provided outside the sealed container 8.

  FIG. 3 is a cross-sectional view showing the configuration of the low-stage compression mechanism (first compression mechanism) shown in FIG. The configuration of the high-stage compression mechanism (second compression mechanism) is the same as that of the low-stage side, and is indicated by reference numerals in parentheses. As the crankshaft 6 rotates about the axis 6d, the crankshaft eccentric portion 6a and the low-stage side rotary piston 12 rotate in the direction indicated by the arrow while being eccentrically in contact with the eccentric direction in the low-stage side cylinder 11. . Rotating in the compression direction with the vane position as a base point, compression starts when the angle in the eccentric direction is the cylinder suction port 15a. When the discharge pressure is reached, the discharge valve 17 is opened and refrigerant gas discharge is started. Note that the holes of the oil supply passage holes 51a and 51b shown in the cross-sectional view of FIG. 3 are used in the fourth embodiment, and are not required in the first embodiment.

  4 and 5 are cross-sectional views exaggeratingly showing a gap to be supplied in the high-stage compression mechanism 20 of the refrigerant compressor of the rotary piston type two-stage rotary compressor of the present invention shown in FIG. The first gap to be lubricated is a bearing gap 70b between the short shaft side bearing 7b and the crankshaft 6, and the surface of the short shaft portion of the crankshaft 6 has a portion with and without a vertical oil groove 56c. . The bearing front end portion without the vertical oil groove 56c also functions as the gap seal portion 73a. The second is an oil supply gap that is a gap to be supplied with oil from the compression mechanism 20. In the illustrated example, the oil supply gap includes seal gaps 72 a and 72 b formed by the upper and lower end surfaces of the rotary piston 22 between the intermediate plate 5 and the lower support member 82, the eccentric circumferential surface of the rotary piston 22, and the cylinder 21. And a sliding clearance 24c between the side surface of the vane 24 and the vane groove of the cylinder 21 that guides the vane 24. 4 and 5, the high-stage compression mechanism 20 has been described. The low-stage compression mechanism 10 has the same configuration and will not be described.

  In FIG. 2, the low-pressure refrigerant once passes from the compressor suction pipe 1 through the inside of the sealed container 8, and then the low-stage side suction pipe 15 b (in this embodiment, the gap between the motor 9 installed in the sealed container 8). Is taken into the suction chamber 15 in the cylinder 11 of the first compression mechanism 10 from the pipe 15b2 outside the sealed container that does not pass through the pipe 15b1 inside the sealed container, which is a path passing through. The refrigerant compressed from the low pressure to the intermediate pressure by the first compression mechanism 10 is discharged from the discharge valve 17 to the discharge muffler 18a. The intermediate-pressure refrigerant is sucked into the suction chamber 25 in the cylinder 21 of the second compression mechanism 20 through the intermediate connecting portion 4, compressed, and then discharged from the discharge valve 27 to the discharge muffler 28 a as a high-pressure refrigerant. . The high-pressure refrigerant enters the high-pressure container 41 of the oil separator 40 outside the sealed container 8 from the high-stage discharge pipe 26b, and the lubricating oil is separated. The high-pressure refrigerant after oil separation is discharged from the compressor discharge pipe 2. It is sent to the refrigerant circuit high-pressure heat exchanger (condenser) side not shown. In the example shown in the figure, an oil separation method in which centrifugal separation by swirling inflow and a demister 47 are combined is used.

  The high-pressure lubricating oil after the oil separation is once stored in the oil storage section 42 in the high-pressure vessel 41, and then passes through the oil supply passage 44 from the oil supply adjustment hole 43 and the low-stage vane back pressure chamber 14 a and the high-stage vane back. It is sent to the pressure chamber 24a. The capillary tube 44a connected to the oil supply path 44 has a flow rate adjusting effect, and the check valve 44b prevents the lubricating oil from accumulating in the cylinder when stopped.

  The lubricating oil sent to the low-stage vane back pressure chamber 14a and the high-stage vane back pressure chamber 24a is pressure-reduced by the throttle 52 in the oil supply passage 53 formed in the intermediate plate 5, and then temporarily crankshaft. 6 and the space 54 formed inside the intermediate plate 5, and from there, the oil is supplied to the in-cylinder seal gaps 71 and 72 of the rotary pistons 12 and 22. As shown in FIGS. 4 and 5, the in-cylinder seal gaps 71 and 72 are short for the rotary piston 22 of the high-stage compression mechanism 20, as shown in FIGS. 4 and 5. It is classified into a seal gap 72b with the shaft side bearing 7b and a seal gap 72c in the direction of eccentricity of the rotary piston. In FIG. 2, the oil supplied to the space 54 is the vertical oil formed on the path of the seal gap 70 a between the end face of the high-stage side rotary piston and the intermediate plate and the surfaces of the crankshaft eccentric parts 6 a and 6 b. Lubricating oil is sent to the groove 56b and the bearing flexible structure groove 57. Therefore, a sufficient amount of oil is sufficiently supplied to the in-cylinder seal gaps 70 and 71 of the rotary pistons 12 and 22, and high sealing performance can be secured. The lubricating oil further flows out into the low-pressure shell-type hermetic container 8 through the bearing gap 70a and the bearing gap 70b between the crankshaft 6 and the long-axis side bearing 7a and the short-axis side bearing 7b. The lubricating oil is stored at 58.

  As described above, the lubricating oil storage section is divided into the oil storage section 58 on the closed container 8 side, which is a low-pressure shell, and the oil storage section 42 on the high-pressure oil separator 40 side. In the present invention, in order to reduce the amount of HC refrigerant stored, a predetermined amount (for example, 2/3) of lubricating oil is stored in the oil storage unit 58 on the low pressure shell side during steady operation, and the oil storage unit 42 on the high pressure oil separator side. In addition, the gap and throttle of the oil supply path are designed so that a predetermined amount (for example, 1/3) or less of the lubricating oil is stored. In order to realize this, the following functions are required.

(1) Reduction of leakage of high-pressure side lubricating oil The path through which the high-pressure side oil circulating in the oil supply path including the oil separator 40 flows out from the circulation path flows out from the compressor discharge pipe 2 to the external circuit, or crankshaft 6 and the bearing gaps 70a and 70b between the bearings 7a and 7b, either flows out into the sealed container 8. In order to stabilize the amount of oil on the high-pressure side, it is necessary that the oil separator 40 has high oil separation efficiency and that there is little leakage from the bearing gaps 70a and 70b. In order to reduce leakage from the bearing gaps 70a and 70b, bearing seal portions 73a and 73b are provided between the crankshaft 6 and the bearings 7a and 7b. In the present embodiment, the bearing gaps 70a and 70b are shown as the bearing seal portions 73a and 73b. However, they can be provided independently. The bearing seal portion 73 includes a gap seal, a labyrinth seal, a commercially available oil seal for rotational motion (JIS, B2402) and a cap seal (for example, manufactured by Mitsubishi Electric Cable).

(2) Oil level adjustment function Since the oil storage balance may be lost, the following oil level adjustment function is provided.
(Example 1) When the oil level of the oil separator oil storage unit 42 rises above the allowable value The oil level adjuster 45 operates to return the lubricating oil to the closed container 8 side through the oil return circuit 48. In the illustrated example, the oil level adjuster 45 is provided with a float 45a having buoyancy in lubricating oil, and the small hole 45b through which the float 5a is pressed downward by a differential pressure and communicates with the oil return circuit 46 during steady operation. However, when the oil level exceeds the permissible oil level, the buoyancy is greater than the differential pressure, the float 45a is lifted, the small hole 45b is opened, and the lubricating oil is returned to the sealed container 8 side through the oil return circuit 48.

  Alternatively, the following oil level adjustment function (Example 1 ') is used. When the oil level of the oil separator oil storage section 42 rises above the allowable value, the finer 37 connected to the small hole opened in the compressor discharge pipe 2 sucks up the lubricating oil and out of compression with the refrigerant. By discharging to the circuit, the oil surface height is adjusted and the oil separator oil storage amount is kept below a predetermined amount.

(Example 2) When the oil level on the closed container 8 side exceeds the allowable value (the lubricating oil on the oil separator 40 side may be depleted) In the low-stage suction pipe 15b, the pipe 15b1 passing through the sealed container 8 Is provided with an oil suction adjusting hole 59, from which lubricating oil is sucked and supplied into the compressor cylinder in a refrigerant mixed state to maintain lubrication performance and sealing performance. Further, when the amount of lubricating oil sucked from the lower stage side increases, the amount of lubricating oil accumulated in the oil separator 40 will be recovered.

(Example 3) When the oil level on the airtight container 8 side is less than the allowable value (there is a risk of stagnation in the refrigerant circuit) The oil pump rotor 61 is attached to the lower end of the hollow portion 60 of the crankshaft 6 to The lubricating oil at the bottom of the oil storage section 58 on the container 8 side is pumped up, and the lubricating oil is diffused from the through hole 62 at the upper end of the hollow section 60 to the lower side of the motor, and formed on the upper surface of the lid 18 b of the low-stage discharge muffler 18. Lubricating oil in the oil sump 63 is sucked from the oil level adjustment drill hole 59 of the pipe 15b1, which is a low-stage suction pipe, and is supplied to the compressor cylinder in a state mixed with the refrigerant to maintain lubrication performance and sealing performance. .

(Example 4) Furthermore, the thin tube 39 connected to the small hole opened in the low-stage side suction pipe 15b2 is led to the bottom of the oil storage section 58 in the sealed container 8 so that the oil level on the side of the sealed container 8 is below the allowable value. Even in the case where there is a risk of stagnation in the refrigerant circuit, a certain amount of lubricating oil is sucked from the oil level adjusting hole 59 of the suction pipe 15b2 and is supplied into the compressor cylinder together with the refrigerant. Keeps performance.

  In the first embodiment, as a path through which the refrigerant is sucked into the low-stage cylinder via the sealed container 8, the pipe 15b1 that is a path passing through the gap of the electric motor installed in the sealed container is temporarily sealed. Two paths 15b2 are provided which go out of the container and do not pass through the gap of the electric motor. The latter path is provided with a valve 32 for adjusting the opening, and the ratio of the flow rate through the two paths is adjusted to adjust the temperature of the refrigerant sucked into the lower stage.

  Table 2 in FIG. 6 shows the effect of the present invention when a propane refrigerant is used. An air conditioning compressor is designed with an input of 1 kW according to the Ashrae-T condition standard. The lubricating oil is paraffinic mineral oil, the pressure in the closed container (low pressure side) oil storage section is 0.59 MPa, the oil temperature is 50 ° C., the refrigerant solubility is 15 wt%, the pressure in the closed container (high pressure side) oil storage section is 1. .88 MPa, temperature is 80 ° C., and refrigerant solubility is 33 wt%. This is a conventional high-pressure shell type two-stage rotary compressor (for example, as shown in Comparative Example 1 of the method of Japanese Patent Application Laid-Open No. 2006-200504). The conventional invention 1 is a low-pressure shell type two-stage rotary compressor designed according to the method of Japanese Patent Application Laid-Open No. 2006-200504. When designed in the first embodiment, it is predicted that the compressor efficiency is 75%, the volume efficiency is 90%, and the refrigerant amount in the compressor is 72g. Compared to the conventional high-pressure shell type rotary compressor, while maintaining the same compressor efficiency and volumetric efficiency, the amount of refrigerant inside the compressor is reduced to about 1/2, and the thickness of the sealed container is about 1/2. Can be reduced. Further, compared with the conventional low pressure shell type rotary compressor of the invention 1, the compressor efficiency and the volume efficiency can be improved by about 10%, and the refrigerant filling amount in the compressor can be kept constant.

Table 3 in FIG. 7 shows the effect of the present invention when a CO ₂ refrigerant is used. In the case of CO ₂ refrigerant, the same effect as in the case of propane refrigerant can be obtained. In particular, in the case of a CO ₂ refrigerant operating at high pressure, the thickness of the sealed container (shell outer diameter 120 mm, cast iron) accounts for a high proportion of processing costs and material costs. Since the thickness can be reduced to about 1/2, the cost can be significantly reduced.

The natural refrigerant (CO ₂ refrigerant and HC refrigerant) low-pressure shell-type rotary compressor having the above-described configuration is (1) vane jump prevention, (2) ensuring lubrication performance of sliding parts (bearings, vanes), ( 3) Ensuring sealing performance of rotating pistons and vanes, (4) Reducing the amount of oil stored on the high-pressure side, satisfying the above simultaneously, enabling higher reliability, lower costs, higher performance, and reduced refrigerant volume .

  In this embodiment, propane refrigerant and paraffinic mineral oil were used for comparison. However, as a weakly compatible refrigerating machine oil having good lubricity to HC refrigerant and CO2 refrigerant, PAG modified oil (PAG (polyalkylene glycol)) EO (Ethylene Oxide) component is blended, and for example, the Barrel Freeze (R) PAG series of Matsumura Oil Co., Ltd.) has been put to practical use. As compared with the above, the refrigerant filling amount in the compressor can be greatly reduced.

  In the first embodiment, the oil supply means for supplying the lubricating oil to the compression mechanism supplies the lubricating oil from the oil storage section 42 through the oil supply preparation hole 43 and the oil supply path 44 to the low-stage vane back pressure chamber 14a and the high pressure side. A first oil supply path (oil supply path supplied to the vane back pressure chamber) for supplying to the stage side vane back pressure chamber 24a is provided. Further, the low-stage side and high-stage vane back pressure chambers 14a and 24a are further supplied to the space 54 between the crankshaft 6 and the intermediate plate 5 through the oil supply path 53, and the compression mechanism 10, A second oil supply path (oil supply path supplied to the oil supply gap of the compression mechanism) for supplying various oil supply gaps including 20 bearing gaps and seal gaps is provided. The second oil supply path includes (1) a path for supplying oil from the space 54 to the seal gaps 70a and 70b between the low-stage side rotary piston and the intermediate plate, and the seal gap 70c between the cylinders 11 and 21; ) A path for supplying oil from the space 54 to the in-cylinder seal gap 70c through the clearance between the crankshaft eccentric portions 6a and 6b and the rotary pistons 12 and 22, the crankshaft oil groove 56b and the bearing flexible structure groove 57; 3) A path for supplying oil to the bearing gaps 70a and 70b between the crankshaft 6, the short shaft side bearing 7b, and the long shaft side bearing 7a through the seal gap 71 between the space 54 and the cylinder of the rotary piston. ing.

Embodiment 2

  FIG. 8 is an assembly diagram showing the overall configuration of the low-pressure shell type two-stage rotary compressor according to the second embodiment. The rotary compressor is different in configuration from the rotary compressor of the first embodiment shown in FIGS. 1 to 7 in that a low-stage discharge muffler 18, a low-stage discharge valve 17 and an intermediate connection are provided. And the oil separator 90 is provided in the internal space 28b of the high-stage discharge muffler container 28 in the sealed container 8 so that it also serves as a high-stage discharge muffler. The oil supply path of the high-pressure lubricating oil separated by the vessel 90 is different. Since the other configuration is the same as that of the first embodiment, the description thereof is omitted.

  That is, the intermediate plate 5 includes two upper and lower laminated plates, that is, a first intermediate plate 5a and a second intermediate plate 5b, and compresses low-pressure refrigerant in the cylinder 11 of the first compression mechanism 10 on the lower stage side. Then, the intermediate pressure refrigerant is discharged from a low-stage discharge valve 17 attached to the first intermediate plate 5a into a low-stage discharge muffler space 18a formed between the first and second intermediate plates 5a and 5b. Is done. Here, it merges with the refrigerant injected from the intermediate injection pipe 31 and flows into the cylinder of the second compression mechanism 20 on the higher stage side from the cylinder suction port 15a.

  In this embodiment, the refrigerant is compressed to a high pressure in the cylinder 21 of the second compression mechanism 20 on the high stage side, and then discharged from the discharge valve 27 to the high stage discharge muffler space 28a that also functions as the oil separator 90. Is done. Lubricating oil is adsorbed when the refrigerant passes through the demister 97, and the adsorbed lubricating oil is collected by gravity in the oil storage section 92 below the high-pressure vessel.

The lubricating oil in the oil storage portion 92 is surrounded by the oil wave breaker plate 92a, and the bearings 7a and 7b are passed through the crankshaft hollow portion 60 from the crankshaft hollow portion through hole 62 by differential pressure from the oil supply thin tube 94c. Bearing gaps 70a and 70b between the shaft 6 and the crankshaft 6, bearing seal portions 73a and 73b, and a bearing 7b sandwiching the rotary pistons 12 and 22 between upper and lower surfaces, seal gaps 71a and 71b between the intermediate plate 5 and the bearing 7a, The oil is supplied to 72a and 72b and further supplied to the rotary piston eccentric direction seal gaps 71c and 72c in the cylinders 11 and 21, and contributes to lubrication and sealing of these movable parts. Further, between these bearing gap 7 0b, bearing seal portion 73a, 73b, and overflow the piston seal gaps 71 and 72, the oil supplied to the inner space of the intermediate plate 5, the oil supply path 53 in the intermediate plate Passed through to the vane back pressure chambers 14a and 24b. As for the vane back pressure, it is appropriate to set the high stage side to a high pressure and the low stage side to an intermediate pressure, and the low stage vane back pressure is reduced from the high pressure by using the throttle channel 52. The lubricating oil supplied to the bearing 7 a is ejected into the closed vessel 8 is a low pressure shell container from the upper end of the gap 70a between the long shaft bearing 7a and the crankshaft 6. Lubricating oil supplied to the other sliding portions (rotary pistons, vanes) enters the cylinder, is mixed with the refrigerant, and is discharged from the high-stage discharge portion 26 to the oil separator 90 and separated. Circulates in the compressor and unseparated oil circulates in the refrigeration cycle circuit.

  In this embodiment, the gap and throttle passage of the oil supply path are designed so that 2/3 of oil is stored in the low pressure shell side oil storage section 58 during steady operation, but the oil storage balance is transiently lost. Since there may be a case, the description closed-case side oil level adjustment function similar to (Example 4) of the first embodiment is provided as follows. Even when the fine officer 39 connected to the small hole of the low-stage side suction pipe 15b1 is led to the bottom of the oil storage section 58 in the sealed container 8 and the oil level on the side of the sealed container 8 becomes less than the allowable value, the pipe 15b1 A predetermined amount of lubricating oil is sucked from the oil level adjusting drill hole 59 and supplied into the compressor cylinder together with the refrigerant to maintain the lubricating performance and the sealing performance.

  The following oil level adjustment function is used. When the oil level of the oil separator oil storage part 92 rises above the allowable value, the finer 37 connected to the small hole opened in the high-pressure side discharge pipe 26b sucks up the lubricating oil, By discharging to the circuit, the oil surface height is adjusted and the oil separator oil storage amount is kept below a predetermined amount.

Table 2 in FIG. 6 shows the effect of the present invention when a propane refrigerant is used. An air conditioning compressor is designed with an input of 1 kW according to the Ashrae-T condition standard. The lubricating oil is paraffinic mineral oil, the pressure in the closed container (low pressure side) oil storage section is 0.59 MPa, the oil temperature is 50 ° C., the refrigerant solubility is 10 wt%, and the pressure in the closed container (high pressure side) oil storage section is 1. .88
MPa, temperature is 80 ° C., refrigerant solubility is 33 wt%. In the conventional general example, for example, a high-pressure shell type two-stage rotary compressor as shown in Comparative Example 1 of the method disclosed in Japanese Patent Application Laid-Open No. 2006-200504 is provided with a suction muffler, and a low-stage compression mechanism is provided with a muffler before suction. The conventional invention 1 is a low-pressure shell type two-stage rotary compressor designed according to the method of Japanese Patent Application Laid-Open No. 2006-200504. When designed in the second embodiment, it is predicted that the compressor efficiency is 75%, the volume efficiency is 90%, and the refrigerant amount in the compressor is 90 g. Compared with the conventional high-pressure shell type rotary compressor, while maintaining the same compressor efficiency and volumetric efficiency, the refrigerant filling amount is reduced to about 2/3, and the closed container thickness is reduced to about 1/2. it can. Moreover, compared with the conventional low pressure shell type rotary compressor of the invention 1, the compressor efficiency and the volume efficiency can be improved by about 10%, and the refrigerant filling amount in the compressor can be kept constant.

In the second embodiment, the oil supply means for supplying the lubricating oil to the compression mechanism includes the first oil supply path for supplying the lubricating oil to the vane back pressure chambers 14a and 24a and the oil supply gap of the compression mechanism. 2 oil supply paths. The second oil supply path consists of (1) bearing gaps 70a, 70b between the bearings 7a, 7b and the crankshaft 6 from the oil storage part 92 through the oil supply thin tube 94c, the crankshaft hollow part 60 and the crankshaft hollow part through hole 62. And (2) a path for supplying from the crankshaft hollow portion through hole 62 to seal gaps 71a and 71b formed between the upper support member 81 and the intermediate plate 5 by the upper and lower end surfaces of the rotary piston 12, Or a path for supplying upper and lower end surfaces of the rotary piston 22 to seal gaps 72a and 72b formed between the intermediate plate 5 and the lower support member 82, respectively, and (3) the cylinder 11, The bearings 7b, the intermediate plate 5, and the bearings 7a sandwiching the rotary pistons 12 and 22 between the upper and lower surfaces are sealed through the seal gaps 70 and 71 between them 21. To) and a path for supplying the rotary piston eccentric direction sealing gap 13, 23 in the cylinder 11, 21. The first oil supply path, the lubricating oil, further from the bearing gap between 7 0b and seal gaps 71 and 72, a fuel supply path for supplying through the oil supply path 53 in the intermediate plate to the vane back pressure chamber 14a and 24a.

The natural refrigerant (CO ₂ refrigerant and HC refrigerant) low-pressure shell-type two-stage rotary compressor having the above-described configuration can achieve the same effects as those of the first embodiment, (1) prevention of vane jumping, (2) Satisfying the lubrication performance of sliding parts (bearings, vanes), (3) ensuring the sealing performance of rotating pistons and vanes, and (4) reducing the amount of oil stored on the high pressure side at the same time. , Increase performance, and reduce the amount of refrigerant.

Embodiment 3

  FIG. 9 is an assembly diagram showing the overall configuration of the low-pressure shell type single-stage rotary compressor according to the second embodiment. The difference in configuration from the rotary compressor of the second embodiment is that it is a single-stage rotary compressor composed of one compression mechanism, and further, the bottom shell structure of the hermetic container 8 is different from the high pressure container 41 for oil separator. This structure also serves as the muffler 18, and a rotating flow generating rotating body 64 acting as oil separating means is provided at the lower end of the crankshaft 6 in the container 41, and an oil pump rotating body 61 is attached as oil supplying means. The other points are the same as in the second embodiment, and a description thereof is omitted. However, the single-stage compression mechanism itself is the same as the compression mechanism of the first embodiment shown in FIGS. 3 to 5, and the symbol of the single-stage compression mechanism is the first (lower stage) of the second embodiment. Represented using reference numerals of the compression mechanism.

  The rotary compressor includes an electric motor 9, a crankshaft 6 driven by the electric motor 9, a short shaft side bearing 7a and a long shaft side bearing 7b that support both ends of the crankshaft 6, and a compression mechanism. 10. The low-pressure refrigerant is sucked into the cylinder 11 of the compression mechanism 10 from the suction pipe 15b1 via the sealed container 8, compressed to a high pressure by the compression mechanism 10, and discharged from the discharge valve 17 with the oil separator 90. It is discharged into the muffler space 18a.

  A swirl flow of the refrigerant is generated at the lower end of the crankshaft 6 by a swirl flow generating rotating body 64 attached thereto, and cyclone oil separation is performed in the high pressure vessel 91 for the oil separator. The lubricating oil blown to the outer periphery by centrifugal force travels along the wall surface and is collected by gravity in the oil storage part 92 below the high-pressure vessel. The oil in the oil storage section 92 is surrounded by an oil wave-dissipating plate 92a, and is attached to the lower end of the crankshaft 6 and lifted and differential pressure of the oil pump rotating together. The oil passes through the hollow portion 60 and is supplied from the crankshaft hollow portion through-hole 62 to the bearing gaps 72 and 73 between the bearings 7a and 7b and the crankshaft 6 and the seal gap 70 between the cylinder of the rotary piston 12 and Contributes to lubrication and sealing. Further, oil is supplied also to the vane back pressure chamber 14a through an oil supply passage 85 formed in the lower support member 82 that also serves as the short shaft side bearing 7b.

  The lubricating oil supplied to the long shaft side bearing 7a is ejected from the upper end of the bearing gap 70a with the crankshaft 6 into the sealed container 8 which is a low pressure shell container. Further, a spiral groove 55b is formed inside the short bearing 7b, and when the crankshaft 6 rotates, the oil is wound down from the top to the bottom, and the lubricating oil supplied to the short shaft side bearing 7b side is: It returns to the oil separator high-pressure vessel 91 from the lower end of the bearing gap 70b with the crankshaft 6. Lubricating oil supplied to the other sliding parts (rotary pistons, vanes) enters the cylinder, is mixed with the refrigerant, and is discharged from the high-stage discharge part 26 to the oil separator 90 and separated. The oil returns to the oil reservoir 92, but the unseparated lubricating oil circulates in the refrigeration cycle circuit.

  Even in this third embodiment, the gap or throttle channel of the oil supply path is designed so that 1/3 of the oil is stored in the low pressure shell side oil storage section 58 during steady operation, but the balance of oil storage is lost. Therefore, oil level adjustment functions (Example 1 ′) and (Example 3 ′) similar to those of the second embodiment are provided.

  In the third embodiment, the oil supply means for supplying the lubricating oil to the compression mechanism supplies the lubricating oil to the vane back pressure chamber 14a through the oil supply passage 85 formed in the lower support member 82 that also serves as the short shaft side bearing 7b. (1) A path for supplying the lubricating oil in the oil storage section 42 from the oil pump rotor 61 to the bearings 7a and 7b through the crankshaft hollow section 60 and the crankshaft hollow section through hole 62 (1) 2) a gap between the crankshafts 6 and (3) a second oil supply path having a path for supplying the gaps between the cylinders of the rotary piston 12.

Since the natural refrigerant (CO ₂ refrigerant and HC refrigerant) low-pressure shell type single-stage rotary compressor having the configuration as described above can achieve the same effects as those of the second embodiment, (1) prevention of vane skipping, (2 ) Ensuring lubrication performance of sliding parts (bearings, vanes), (3) Ensuring sealing performance of rotating pistons and vanes, (4) Reducing oil storage on the high-pressure side, satisfying the above issues at the same time, improving reliability, Enables cost reduction, higher performance, and reduced refrigerant volume.

Embodiment 4

  FIG. 10 is an assembly diagram showing the overall configuration of the low-pressure shell type two-stage rotary compressor according to the fourth embodiment. This rotary compressor is the same as the rotary compressor of the second embodiment in that the oil separation element 90 also serves as the high-stage discharge muffler 28 in the sealed container 8, but in addition to this, the rotary compressor is also installed outside the sealed container. The difference is that an oil separation element 40 is also provided.

  After being sucked into the suction chamber 25 in the cylinder 21 of the second compression mechanism and compressed, it is discharged as a high-pressure refrigerant from the discharge valve 27 to the internal space 28a of the discharge muffler 28, where centrifugal separation by swirling inflow is performed. The oil separated by the oil separation method combined with the demister 101 passes through the punch metal 102 and is temporarily stored in 92 and passes through an oil supply path 86 opened in the oil separator container 91 and the lower support member 82. The high stage vane back pressure chamber 24a is supplied to the upper stage lower end face seal gaps 72a and 72b through the oil supply path 85 opened in the lower support member 82. Oil supply grooves 22a and 22b are cut in a ring shape on the upper and lower end surfaces of the oil 22 and oil is supplied here. When the amount of oil stored in 92 exceeds the reference value, the oil is sucked into the refrigerant flowing in 26b through the narrow pipe 38 connected to the high-stage discharge pipe 26b, and supplied from 26b to the oil separator 40 outside the sealed container. Is done. The oil separated at 40 is supplied from the oil supply path 44 to the low-stage vane back pressure chamber 14a. In order to keep the oil amount of the oil separating element 40 stable in a small state, means for suppressing the return amount is used when the oil amount decreases. For example, a capillary capillary is used in the oil supply path to increase the flow resistance in a gas-mixed state. Alternatively, a means for floating the oil storage unit 42 to float 45a and increasing the flow resistance of the oil supply passage port when the oil level is lowered is used. Further, the clearance seals 73a and 73b of the bearings 7a and 7b are arranged so as to be distinguished from the bearing clearances 70a and 70b. The gap seals 73a and 73b have an effect of making it difficult for oil to leak into the bearing gap from the gap between the upper and lower end surfaces of the rotary piston.

  An oil pump rotator 61 is attached to the lower end of the hollow portion 60 of the crankshaft 6 to pump up the low-pressure lubricating oil at the bottom of the oil storage portion 58 on the closed container 8 side, and to pass through the hollow portion through hole 62a. 60b, oil is supplied to the gaps 70a and 70b between the crankshaft 6 and the main bearings 7a and 7b. A spiral groove 55a is formed on the inner peripheral side of the bearing 7a. When the crankshaft 6 rotates, the oil can be wound up from the bottom to the top, so that the oil can be supplied to the upper end of the bearing gap 7a.

  Further, oil can be supplied to the bearing gap 70b from 62b, and can be supplied to the entire bearing gap 7b through a flow path 55d provided on the inner peripheral side of the bearing 7b. If the bearing oil supply method as in the fourth embodiment is used, the main bearings 7a and 7b can be supplied with oil even if the low-pressure side oil amount in the sealed container is excessively reduced. Can do.

  In the case of designing in the fourth embodiment, the compressor efficiency is 70% and the volume efficiency is 85%, and the refrigerant amount in the compressor is predicted to be 72 g. Compared with the conventional high-pressure shell type rotary compressor, although the compressor efficiency and volumetric efficiency are slightly reduced, the amount of refrigerant filled can be reduced to about 1/2, and the thickness of the sealed container can be reduced to about 1/2. . Further, compared with the conventional low pressure shell type rotary compressor of the invention 1, the compressor efficiency and the volume efficiency can be improved by about 5%, and the refrigerant filling amount in the compressor can be kept constant.

Since the natural refrigerant (CO ₂ refrigerant and HC refrigerant) low-pressure shell type single-stage rotary compressor having the above-described configuration can obtain the same effects as those of the first embodiment, (1) prevention of vane skipping, (2 ) Ensuring lubrication performance of sliding parts (bearings, vanes), (3) Ensuring sealing performance of rotating pistons and vanes, (4) Reducing oil storage on the high-pressure side, satisfying the above issues at the same time, improving reliability, Enables cost reduction, higher performance, and reduced refrigerant volume.

In the above embodiment, the effect of using the HC refrigerant in the low-pressure shell-type rotary compressor of the present invention has been shown. However, various refrigerants such as a CO ₂ refrigerant and a chlorofluorocarbon refrigerant other than the HC refrigerant can be used. , Respectively (1) prevent vane jumping, (2) ensure lubrication performance of sliding parts (bearings, vanes), (3) ensure sealing performance of rotating pistons and vanes, (4) reduce oil storage on the high pressure side The above can be satisfied at the same time, and reliability, cost reduction, high performance, and reduction of the refrigerant amount can be achieved. Reducing the amount of chlorofluorocarbon refrigerant is effective for global warming countermeasures, and is effective from the viewpoint of safety when there is flammability or toxicity.

  As shown in the first, second, and third embodiments, in the low-pressure shell type two-stage rotary compressor, the path for supplying the high-pressure side lubricating oil to the sliding part (bearing, vane) and the seal part is provided in the intermediate plate. As a result, a compact configuration can be realized at low cost.

  In the above embodiment, the case of the rotary piston type has been described as the low pressure shell type rotary compressor. However, the present invention can be applied to various rotary compressors such as a sliding vane type and a swing type. In the case of the sliding vane type, the same effect as that of the rotary piston type is obtained, and in the case of the swing type, the same effect other than (1) prevention of vane jumping is obtained.

Claims (3)

A sealed container that is connected to an external refrigerant circuit by a suction pipe and a discharge pipe and encloses a low-pressure refrigerant, an electric motor provided in the closed container, and a low-pressure refrigerant that is sucked and compressed in the sealed container. A bearing between a low-stage compression mechanism that discharges at an intermediate pressure, a high-stage compression mechanism that sucks and compresses an intermediate-pressure refrigerant and discharges it at a high pressure, a crankshaft connected to the electric motor, and the crankshaft A bearing that supports the crankshaft so that a gap is formed;
Each of the low-stage compression mechanism and the high-stage compression mechanism includes a rotary piston that is driven by the crankshaft and rotates eccentrically in the cylinder, a suction chamber and a compression chamber are formed in the cylinder, and a vane back is formed in the back. An oil supply gap for sliding the vane forming the pressure chamber while sealing the compression chamber is formed,
High pressure that supplies the lubricating oil separated by the oil separation element through which the high-pressure refrigerant compressed by the high-stage compression mechanism is discharged to the external refrigerant circuit to the vane back pressure chamber of the high-stage compression mechanism A plurality of supply passages, and a plurality of oil supplies the lubricating oil to each of the oil supply gap and the bearing gap excluding the vane back pressure chamber of the high stage compression mechanism and the vane back pressure chamber of the low stage compression mechanism anda feed oil path,
The oil separation element and the low-stage compression so that the refrigerant pressure in the vane back-pressure chamber of the low-stage compression mechanism is lower than the refrigerant pressure in the vane back-pressure chamber of the high-stage compression mechanism. A rotary compressor characterized in that the flow resistance of the oil supply path for guiding lubricating oil to the vane back pressure chamber of the mechanism is adjusted. The pressure of the refrigerant in the oil supply gap of the high-stage compression mechanism, so as to be higher than the pressure of the refrigerant in the oil supply gap of the low-pressure compression mechanism, the flow path of the oil separator element and the upper Symbol supply oil passage The rotary compressor according to claim 1, wherein the resistance is adjusted. Main component of the refrigerant is carbon dioxide or a propane, propylene is either a hydrocarbon, such as, and claim 1 or claim 2, wherein the main component of the lubricating oil is a polyalkyl glycol The rotary compressor described in 1.

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