Rotary compressor

Abstract

To reduce a dead volume while facilitating manufacturing.SOLUTION: A rotary compressor according to an embodiment includes: a compression part for compressing a coolant; a motor for driving the compression part; and a compressor body container for storing the compression part and the motor therein. The compression part has: a cylinder forming a cylinder chamber therein; a piston revolving on an inner peripheral side of the cylinder; and an end plate for closing an end part of the cylinder. An injection hole that communicates with the cylinder chamber and through which an injection pipe for guiding the coolant can be inserted is formed on the end plate. The injection pipe is fixed to the injection hole via a holding pipe for holding an outer periphery of the injection pipe.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a rotary compressor.

Background Art

[0002] As a rotary compressor, a rotary compressor is known in which a compression part for compressing a refrigerant and a motor for driving the compression part are arranged inside a compressor main body container. This rotary compressor is mounted on, for example, a refrigeration cycle device.

[0003] In a compressor mounted on a refrigeration cycle device, a prior art of a liquid injection method is known in which a part of the condensed liquid refrigerant is branched and the branched liquid refrigerant is injected (injected) into the cylinder chamber of the compressor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a compressor of the liquid injection method, by providing an on-off valve in the middle of the injection passage branched from the condenser outlet, it becomes possible to switch whether to perform injection (perform injection operation) or not. However, in this compressor, when the injection operation is not performed, the space from the on-off valve provided in the injection passage to the cylinder chamber becomes a dead volume (dead volume). For this reason, there is a problem that the compression efficiency is reduced because the compressed refrigerant expands again.

[0006] In the rotary compressor described in Patent Document 1, a slide valve is provided in an injection passage extending in the radial direction of a partition plate, and when opening an injection port communicating with a cylinder chamber, the slide valve is not positioned within the injection passage. On the other hand, when closing the injection port, the slide valve is arranged at the position of the injection port so that refrigerant does not flow backward into the injection passage, thereby reducing the dead volume when injection operation is not performed. Such a slide structure has problems that the structure of a spring and the slide valve becomes complicated and manufacturing is difficult. Also, there is a possibility that the reliability of the compressor may decrease due to the injection not being performed normally due to a failure or the like of the slide structure.

[0007] Also, in the rotary compressor described in Patent Document 2, it is conceivable to form the injection pipe itself thinner. However, when simply thinning the injection pipe, it is difficult to fix the injection pipe to an injection hole (lateral hole), and there is also a problem that manufacturing is difficult in this case.

[0008] The disclosed technology has been made in view of the above, and an object thereof is to provide a rotary compressor provided with an injection mechanism capable of reducing the dead volume while facilitating manufacturing.

Means for Solving the Problems

[0009] The rotary compressor according to an embodiment of the present disclosure includes a compression unit that compresses refrigerant, a motor that drives the compression unit, and a compressor main body container that houses the compression unit and the motor therein. The compression unit has a cylinder that forms a cylinder chamber inside, a piston that revolves on the inner peripheral side of the cylinder, and an end plate that closes an end of the cylinder. An injection hole communicating with the cylinder chamber and through which an injection pipe for conducting refrigerant can be inserted is formed in the end plate. The injection pipe is fixed to the injection hole via a holding pipe that holds the outer periphery of the injection pipe.

Effects of the Invention

[0010] According to the disclosed technology, it is possible to reduce the dead volume while facilitating manufacturing.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

MODE FOR CARRYING OUT THE INVENTION

[0012] Hereinafter, a rotary compressor according to an embodiment will be described with reference to the drawings. Components having the same function in the embodiments are denoted by the same reference numerals, and overlapping descriptions are omitted. Note that the rotary compressor described in the following embodiments is merely an example and does not limit the embodiments. Also, the following embodiments may be appropriately combined within a non - conflicting range.

[0013] FIG. 1 is a longitudinal sectional view showing an example of a rotary compressor according to an embodiment. FIG. 2 is a cross - sectional view taken from above of a first compression section and a second compression section.

[0014] As shown in FIG. 1, the rotary compressor 1 includes a compression section 12 disposed at the lower part of a sealed vertically - arranged cylindrical compressor housing 10, and a motor 11 disposed at the upper part of the compressor housing 10 and driving the compression section 12 via a rotating shaft 15.

[0015] The stator 111 of the motor 11 is formed in a cylindrical shape and is fixed by shrink - fitting to the inner peripheral surface of the compressor housing 10. The rotor 112 of the motor 11 is disposed inside the cylindrical stator 111 and is fixed by shrink - fitting to a rotating shaft 15 that mechanically connects the motor 11 and the compression section 12.

[0016] The compression unit 12 includes a first compression unit 12S and a second compression unit 12T which is arranged in parallel with the first compression unit 12S and laminated on the upper side of the first compression unit 12S. As shown in Fig. 2, the first compression unit 12S includes an annular first cylinder 121S provided with a first suction hole 135S and a first vane groove 128S radially in the first side overhanging portion 122S. Similarly, the second compression unit 12T includes an annular second cylinder 121T provided with a second suction hole 135T and a second vane groove 128T radially in the second side overhanging portion 122T.

[0017] As shown in Fig. 2, circular first cylinder inner walls 123S and second cylinder inner walls 123T are formed concentrically with the rotating shaft 15 of the motor 11 in the first cylinder 121S and the second cylinder 121T. In the first cylinder inner wall 123S and the second cylinder inner wall 123T, first annular pistons 125S and second annular pistons 125T with outer diameters smaller than the cylinder inner diameter are respectively arranged. A first cylinder chamber 130S for sucking, compressing and discharging the refrigerant gas is formed between the first cylinder inner wall 123S and the first annular piston 125S. Similarly, a second cylinder chamber 130T for sucking, compressing and discharging the refrigerant gas is formed between the second cylinder inner wall 123T and the second annular piston 125T.

[0018] In the first cylinder 121S, a first vane groove 128S extending in the radial direction from the first cylinder inner wall 123S over the entire cylinder height is formed. Similarly, in the second cylinder 121T, a second vane groove 128T extending in the radial direction from the second cylinder inner wall 123T over the entire cylinder height is formed. Flat first vanes 127S and second vanes 127T are respectively and slidably fitted in the first vane groove 128S and the second vane groove 128T.

[0019] As shown in Fig. 2, a first spring hole 124S is formed at the inner end of the first vane groove 128S so as to communicate with the first vane groove 128S from the outer peripheral portion of the first cylinder 121S. Similarly, a second spring hole 124T is formed at the inner end of the second vane groove 128T so as to communicate with the second vane groove 128T from the outer peripheral portion of the second cylinder 121T. A first vane spring 260S (see Fig. 3) that presses the back surface of the first vane 127S is inserted into the first spring hole 124S. Similarly, a second vane spring 260T (see Fig. 3) that presses the back surface of the second vane 127T is inserted into the second spring hole 124T.

[0020] When the rotary compressor 1 is started, due to the repulsive force of the first vane spring 260S, the first vane 127S projects from the first vane groove 128S into the first cylinder chamber 130S. Similarly, when the rotary compressor 1 is started, due to the repulsive force of the second vane spring 260T, the second vane 127T projects from the second vane groove 128T into the second cylinder chamber 130T. Then, the tip of the first vane 127S abuts against the outer peripheral surface of the first annular piston 125S. Similarly, the tip of the second vane 127T abuts against the outer peripheral surface of the second annular piston 125T. The first cylinder chamber 130S is partitioned into a first suction chamber 131S and a first compression chamber 133S by the first vane 127S that abuts in this way. Also, the second cylinder chamber 130T is partitioned into a second suction chamber 131T and a second compression chamber 133T by the second vane 127T.

[0021] In addition, the first and second cylinders 121S and 121T communicate the inner ends of the first and second vane grooves 128S and 128T with the inside of the compressor housing 10 through the opening R shown in Fig. 1. First and second pressure introduction paths 129S and 129T are formed to introduce the refrigerant gas compressed in the compressor housing 10 through this opening R and apply back pressure to the first and second vanes 127S and 127T by the pressure of the refrigerant gas.

[0022] The first and second cylinders 121S and 121T are provided with first and second suction holes 135S and 135T for communicating the first and second suction chambers 131S and 131T with the outside in order to suck refrigerant from the outside into the first and second suction chambers 131S and 131T.

[0023] Also, as shown in FIG. 1, an intermediate partition plate 140 is disposed between the first cylinder 121S and the second cylinder 121T, partitioning and closing the first cylinder chamber 130S (see FIG. 2) of the first cylinder 121S and the second cylinder chamber 130T (see FIG. 2) of the second cylinder 121T. The intermediate partition plate 140 closes the upper end portion of the first cylinder 121S and the lower end portion of the second cylinder 121T. That is, the intermediate partition plate 140 is an example of an end plate that closes the end portion of the cylinder.

[0024] A lower end plate 160S is disposed at the lower end portion of the first cylinder 121S, closing the first cylinder chamber 130S of the first cylinder 121S. Also, an upper end plate 160T is disposed at the upper end portion of the second cylinder 121T, closing the second cylinder chamber 130T of the second cylinder 121T. The lower end plate 160S closes the lower end portion of the first cylinder 121S, and the upper end plate 160T closes the upper end portion of the second cylinder 121T.

[0025] A sub-bearing portion 161S is formed on the lower end plate 160S, and a sub-shaft portion 151 of the rotating shaft 15 is rotatably supported by the sub-bearing portion 161S. A main-bearing portion 161T is formed on the upper end plate 160T, and a main-shaft portion 153 of the rotating shaft 15 is rotatably supported by the main-bearing portion 161T.

[0026] The rotating shaft 15 includes a first eccentric portion 152S and a second eccentric portion 152T that are eccentric with a 180° phase shift from each other. The first eccentric portion 152S is rotatably fitted to the first annular piston 125S of the first compression portion 12S. The second eccentric portion 152T is rotatably fitted to the second annular piston 125T of the second compression portion 12T.

[0027] When the rotating shaft 15 rotates, the first and second annular pistons 125S and 125T revolve clockwise in the first and second cylinders 121S and 121T along the first and second cylinder inner walls 123S and 123T as shown in FIG. 2. Following this revolution, the first and second vanes 127S and 127T reciprocate. Due to the movement of the first and second annular pistons 125S and 125T and the first and second vanes 127S and 127T, the volumes of the first and second suction chambers 131S and 131T and the first and second compression chambers 133S and 133T continuously change. Also, in the compression section 12, the refrigerant gas is continuously sucked, compressed, and discharged.

[0028] As shown in FIG. 1, a lower muffler cover 170S is disposed below the lower end plate 160S, and a lower muffler chamber 180S is formed between the lower end plate 160S. And the first compression section 12S opens into the lower muffler chamber 180S. That is, near the first vane 127S of the lower end plate 160S, a first discharge hole 190S (see FIG. 2) that communicates the first compression chamber 133S of the first cylinder 121S with the lower muffler chamber 180S is provided. A reed valve type first discharge valve 200S for preventing the backflow of the compressed refrigerant gas is disposed in the first discharge hole 190S.

[0029] The lower muffler chamber 180S is a single annularly formed chamber and is part of a communication passage that communicates the discharge side of the first compression section 12S into the upper muffler chamber 180T through a refrigerant passage 136 (see FIG. 2) that penetrates the lower end plate 160S, the first cylinder 121S, the intermediate partition plate 140, the second cylinder 121T, and the upper end plate 160T. The lower muffler chamber 180S reduces the pressure pulsation of the discharged refrigerant gas. Also, a first discharge valve retainer 201S for restricting the deflection opening amount of the first discharge valve 200S is fixed to the first discharge valve 200S by a rivet on top of the first discharge valve 200S. The first discharge hole 190S, the first discharge valve 200S, and the first discharge valve retainer 201S constitute the first discharge valve portion of the lower end plate 160S.

[0030] As shown in FIG. 1, an upper muffler cover 170T is disposed above the upper end plate 160T, and an upper muffler chamber 180T is formed between the upper end plate 160T. Near the second vane 127T of the upper end plate 160T, a second discharge hole 190T (see FIG. 2) that communicates the second compression chamber 133T of the second cylinder 121T with the upper muffler chamber 180T is provided. A reed valve type second discharge valve 200T for preventing the backflow of the compressed refrigerant gas is disposed in the second discharge hole 190T. Further, a second discharge valve presser 201T for limiting the deflection opening amount of the second discharge valve 200T is fixed to the second discharge valve 200T by a rivet together with the second discharge valve 200T. The upper muffler chamber 180T reduces the pressure pulsation of the discharged refrigerant. The second discharge hole 190T, the second discharge valve 200T, and the second discharge valve presser 201T constitute the second discharge valve portion of the upper end plate 160T.

[0031] The first cylinder 121S, the lower end plate 160S, the lower muffler cover 170S, the second cylinder 121T, the upper end plate 160T, the upper muffler cover 170T, and the intermediate partition plate 140 are integrally fastened by a plurality of through bolts 175 or the like. Among the compression portions 12 integrally fastened by the through bolts 175 or the like, the outer peripheral portion of the upper end plate 160T is fixed to the compressor housing 10 by spot welding, and the compression portion 12 is fixed to the compressor housing 10.

[0032] On the outer peripheral wall of the cylindrical compressor housing 10, a first through hole 101 and a second through hole 102 are provided in order from the bottom at intervals in the axial direction for passing the first suction pipe 104 and the second suction pipe 105. Further, outside the compressor housing 10, an accumulator 25 composed of an independent cylindrical sealed container is held by an accumulator holder 252 and an accumulator band 253.

[0033] At the center of the top portion of the accumulator 25, a system connection pipe 255 connected to the evaporator of the refrigerant circuit is connected. To the bottom through-hole 257 provided at the bottom of the accumulator 25, a first low-pressure connection pipe 31S and a second low-pressure connection pipe 31T are fixed, one end of which extends upward inside the accumulator 25 and the other end of which is connected to the other ends of the first suction pipe 104 and the second suction pipe 105.

[0034] The first low-pressure connection pipe 31S that guides the low-pressure refrigerant of the refrigerant circuit to the first compression part 12S via the accumulator 25 is connected to the first suction hole 135S (see FIG. 2) of the first cylinder 121S via the first suction pipe 104 as a suction part. Also, the second low-pressure connection pipe 31T that guides the low-pressure refrigerant of the refrigerant circuit to the second compression part 12T via the accumulator 25 is connected to the second suction hole 135T (see FIG. 2) of the second cylinder 121T via the second suction pipe 105 as a suction part. That is, the first suction hole 135S and the second suction hole 135T are connected in parallel to the evaporator of the refrigerant circuit.

[0035] At the top of the compressor housing 10, a discharge pipe 107 as a discharge part that connects to the refrigerant circuit and discharges high-pressure refrigerant gas to the condenser side of the refrigerant circuit is connected. That is, the first discharge hole 190S and the second discharge hole 190T are connected to the condenser of the refrigerant circuit.

[0036] Inside the compressor housing 10, lubricating oil is enclosed up to approximately the height of the second cylinder 121T. Also, the lubricating oil is sucked up from an oil supply pipe 16 attached to the lower end of the rotating shaft 15 by pump blades (not shown) inserted into the lower part of the rotating shaft 15 and circulates through the compression part 12. Thereby, the lubricating oil lubricates the sliding parts and seals the minute gaps of the compression part 12.

[0037] FIG. 3 is a partial longitudinal sectional view showing a compression section 12 of a rotary compressor 1 according to an embodiment. As shown in FIG. 3, an injection hole 300 is formed in an intermediate partition plate 140, which communicates with a first cylinder chamber 130S through a communication hole 302S and with a second cylinder chamber 130T through a communication hole 302T, and through which an injection pipe 141 for supplying refrigerant can be inserted. An injection pipe 141 is fixed to the injection hole 300 via a holding pipe 142 that holds the outer periphery of the injection pipe 141.

[0038] In recent years, refrigeration cycle devices using heat pumps have become increasingly popular even in cold regions with low outside air temperatures. When an evaporator is used in an environment with a low outside air temperature, the density of the refrigerant sucked into the compression section 12 decreases, making it difficult to obtain sufficient heating capacity. For this reason, a part of the liquid refrigerant on the outlet side of the condenser or after passing through the pressure reducing means is branched, and the branched liquid refrigerant is injected into the first cylinder chamber 130S and the second cylinder chamber 130T of the compression section 12 through the injection pipe 141, that is, liquid injection (gas injection for injecting gaseous refrigerant may also be performed) is carried out.

[0039] By performing this liquid injection, the circulation amount of the refrigerant can be increased and the heating capacity can be improved. Further, when the outside air temperature is low during heating, the operation is performed under conditions with a large compression ratio, so the refrigerant temperature in the first cylinder chamber 130S and the second cylinder chamber 130T becomes high. However, by performing liquid injection, the refrigerant temperature can be lowered by cooling the inside of the cylinder chamber with the latent heat of vaporization of the liquid refrigerant.

[0040] Figures 4 to 7 are partial cross-sectional views showing the injection holes 300 of the intermediate partition plate 140. Specifically, Figure 4 is a partial cross-sectional view before inserting the injection pipe 141 and the holding pipe 142 into the injection hole 300. Figure 5 is a partial cross-sectional view after inserting the holding pipe 142 into the injection hole 300. Figure 6 is a partial cross-sectional view after inserting the injection pipe 141 and the holding pipe 142 into the injection hole 300. Figure 7 is a partial cross-sectional view illustrating a configuration in which the tip 141a of the injection pipe is sealed with a sealing member 143.

[0041] As shown in Figure 4, the injection hole 300 has a structure in which the inner diameter gradually decreases from the outer opening 301 of the intermediate partition plate 140 toward the inner communication holes 302S and 302T. Specifically, the injection hole 300 has a gradually decreasing inner diameter in the order of the opening 301, the large-diameter portion 303, the first step portion (first tapered portion) 304, the first small-diameter portion 305, the second step portion (second tapered portion) 306, and the second small-diameter portion 307. And in the second small-diameter portion 307, a communication hole 302S communicating with the first cylinder chamber 130S and a communication hole 302T communicating with the second cylinder chamber 130T are provided.

[0042] The large-diameter portion 303 is continuously formed from the opening 301 toward the inner first step portion (first tapered portion) 304. As shown in Figure 5, the large-diameter portion 303 has an inner diameter slightly larger than the outer diameter of the holding pipe 142 from the opening 301 and is configured to allow the holding pipe 142 to pass through.

[0043] As shown in Figure 4, the large-diameter portion 303 has, for example, a gentle tapered shape in which the inner diameter gradually decreases toward the inner side. Note that the large-diameter portion 303 may have a cylindrical shape in which the inner diameter does not change from the opening 301 side to the inner first step portion (first tapered portion) 304. Also, the large-diameter portion 303 may have a shape in which the inner diameter gradually decreases toward the inner side and, for example, has the same inner diameter as the first small-diameter portion 305 at the position of the first tapered portion 304, that is, a shape in which the entire large-diameter portion 303 has a tapered shape and does not have the first step portion.

[0044] The first step portion (first tapered portion) 304 extending from the large-diameter portion 303 to the first small-diameter portion 305 has a tapered shape such that the diameter continuously decreases toward the back. That is, the first small-diameter portion 305 is continuously formed from the large-diameter portion 303 via the first step portion (first tapered portion) 304, has a smaller diameter than the large-diameter portion 303, and is located closer to the communication holes 302S and 302T than the large-diameter portion 303. Note that the first step portion 304 located between the large-diameter portion 303 and the first small-diameter portion 305 is not limited to a tapered shape and may be formed by a step perpendicular to the direction in which the injection pipe 141 extends, for example.

[0045] The first small-diameter portion 305 is continuously formed from the front first step portion (first tapered portion) 304 toward the back second step portion (second tapered portion) 306. For example, the first small-diameter portion 305 has a cylindrical shape with an inner diameter that does not change from the first step portion (first tapered portion) 304 side to the back second step portion (second tapered portion) 306. The inner diameter of the first small-diameter portion 305 is slightly larger than the outer diameter of the injection pipe 141, and is configured to allow the injection pipe 141 to be inserted therethrough.

[0046] The second step portion (second tapered portion) 306 extending from the first small-diameter portion 305 to the second small-diameter portion 307 has a tapered shape such that the diameter gradually decreases toward the back. That is, the second small-diameter portion 307 has a smaller diameter than the first small-diameter portion 305 and is continuously formed from the first small-diameter portion 305 via the second step portion (second tapered portion) 306. Note that the second step portion 306 located between the first small-diameter portion 305 and the second small-diameter portion 307 is not limited to a tapered shape and may be formed by a step perpendicular to the direction in which the injection pipe 141 extends, for example.

[0047] As shown in FIG. 6, the holding tube 142 is inserted from the opening 301 of the injection hole 300 and fixed, for example, by a hole-side tapered portion formed in the injection hole 300. The hole-side tapered portion where the holding tube 142 is fixed may be formed by the inner peripheral surface itself of the large-diameter portion 303 being formed in a gentle tapered shape. In this case, as shown in FIGS. 5 and 6, a hole-side tapered portion 303a is formed in the large-diameter portion 303, and the tip 142a of the holding tube is fixed in the middle of the large-diameter portion 303 having a gentle tapered shape. Alternatively, the hole-side tapered portion where the holding tube 142 is fixed may be the first step portion (first tapered portion) 304. In this case, although not shown, the tip 142a of the holding tube is fixed when it abuts against the first step portion (first tapered portion) 304. Thus, when the holding tube 142 is fixed to the injection hole 300, the tip 142a of the holding tube is positioned in the large-diameter portion 303, and the positioning of the tip 142a of the holding tube at the time of insertion is performed by the hole-side tapered portions (303a, 304). The inner diameter R1 of this holding tube 142 is equal to or greater than the outer diameter R2 of the injection tube 141, and for example, a copper tube or the like can be applied.

[0048] The injection tube 141 is formed thinner (R1 > R2) than the holding tube 142 over the entire portion held by the inner wall surface of the holding tube 142 by being inserted into the holding tube 142. For this reason, the injection tube 141 is inserted into the first small-diameter portion 305 through the holding tube 142 fixed to the injection hole 300, and for example, the injection tube tip 141a is fixed when it abuts against the second step portion (second tapered portion) 306.

[0049] In this way, when the injection pipe 141 is fixed to the injection hole 300 via the holding pipe 142, the tip 141a of the injection pipe is positioned at the first small-diameter portion 305, and the second stepped portion (second tapered portion) 306 positions the tip 141a of the injection pipe when it is inserted. By such positioning, the outlet portion (the tip 141a of the injection pipe) from which the refrigerant discharges from the injection pipe 141 is positioned at the inlet portion of the second small-diameter portion 307. That is, the second small-diameter portion 307 is configured to be continuous from the outlet of the injection pipe 141 when the injection pipe 141 is fixed to the injection hole 300.

[0050] Also, let the inner diameter R3 of the injection pipe 141 be smaller than the inner diameter R4 of the second small-diameter portion 307 (R4 > R3). Thereby, in the rotary compressor 1, the refrigerant can be discharged into the second small-diameter portion 307 from the outlet of the injection pipe 141 without stagnation.

[0051] Further, as shown in FIG. 7, a sealing member 143 may be provided at the tip 141a of the injection pipe 141 so as to close the gap between the inner peripheral surface of the first small-diameter portion 305 in the injection hole 300 and the outer peripheral surface of the injection pipe 141. For example, an O-ring made of an elastic rubber material, a gasket made of non-elastic Teflon (registered trademark), etc. can be applied as the sealing member 143. In this way, by closing the gap between the inner peripheral surface of the first small-diameter portion 305 in the injection hole 300 and the outer peripheral surface of the injection pipe 141 with the sealing member 143, it is possible to prevent the refrigerant discharged to the second small-diameter portion 307 side from leaking out from the intermediate partition plate 140.

[0052] Here, regardless of the presence or absence of the sealing member 143, the dimension of the gap formed between the inner peripheral surface of the first small-diameter portion 305 of the injection hole 300 and the outer peripheral surface of the tip 141a of the injection pipe is preferably 50 μm or less. In this way, the rotary compressor 1 can prevent the refrigerant injected from the tip 141a of the injection pipe from leaking out through the above gap by setting the dimension of the gap between the inner peripheral surface of the first small-diameter portion 305 and the outer peripheral surface of the tip 141a of the injection pipe to 50 μm or less.

[0053] As this injection pipe 141, for example, a copper pipe having an outer diameter R2 of 4 mm or less and an inner diameter R3 of about 3 mm can be applied. Thereby, in the rotary compressor 1 of the embodiment, the injection pipe 141 functions as a capillary tube having a smaller inner diameter than the pipe connected to its upstream side, and the pressure of the refrigerant passing through the inside of the injection pipe 141 can be reduced.

[0054] FIG. 8 is an explanatory diagram for explaining a comparison with a conventional example of the dead volume in the injection mechanism of the rotary compressor 1. Specifically, FIG. 8(a) illustrates the dead volume DV1 in the injection mechanism of the rotary compressor 1 of the embodiment, and FIG. 8(b) illustrates the dead volume DV2 of the injection mechanism in the intermediate partition plate 500 of the conventional rotary compressor.

[0055] As shown in FIG. 8(a), an injection hole 300 through which an injection pipe 141 for supplying refrigerant and communicating with the first cylinder chamber 130S and the second cylinder chamber 130T through communication holes 302S and 302T is formed in the intermediate partition plate 140 of the rotary compressor 1. The injection pipe 141 is fixed to the injection hole 300 through a holding pipe 142 that holds the outer periphery of the injection pipe 141.

[0056] As a result, in the rotary compressor 1, the injection pipe 141, which is formed to be thin (for example, the outer diameter R2 is 4 mm or less) so as to reduce the volume that becomes the dead volume when the injection operation is not performed, can be easily installed near the communication holes 302S and 302T in the injection hole 300 via the holding pipe 142. For this reason, as is clear from a comparison between the dead volume DV1 of the rotary compressor 1 of the embodiment shown in FIG. 8(a) and the dead volume DV2 of the conventional rotary compressor 1 in which the injection pipe 141 shown in FIG. 8(b) is not inserted into the injection hole 300, in the rotary compressor 1 of the embodiment, the dead volume when the injection operation is not performed can be reduced.

[0057] FIGS. 9(a) to 9(c) are radial cross-sectional views and cross-sectional views in a direction orthogonal to the rotary shaft 15 showing the rotation cycle of the annular piston 125 in a rotary compressor provided with a conventional injection mechanism. As shown in FIG. 9, communication holes 302S and 302T communicating with the injection hole 300 are formed in the intermediate partition plate 500. When the injection operation is performed, the liquid refrigerant discharged from the injection pipe 141 is introduced into the first cylinder chamber 130S through the communication hole 302S and into the second cylinder chamber 130T through the communication hole 302T. FIG. 9 shows the rotation cycle of the first annular piston 125S inside the first cylinder chamber 130S when the injection operation is not performed. Note that FIG. 9(a) illustrates the state of the annular piston 125S at the timing (point A) when the rotation angle of the first annular piston 125S is about 40 degrees. FIG. 9(b) illustrates the state of the annular piston 125S at the timing (point B1) when the rotation angle of the first annular piston 125S is about 130 degrees. FIG. 9(c) illustrates the state of the annular piston 125S at the timing (point C) when the rotation angle of the first annular piston 125S is about 200 degrees.

[0058] FIG. 10 is a graph showing a comparison between the change in the pressure inside the first cylinder chamber 130S (graph G11) when injection operation is not performed (in other words, when the on-off valve connected to the injection pipe is closed) in a rotary compressor equipped with the injection mechanism of the conventional example shown in FIG. 8(b), and the change in the pressure inside the first cylinder chamber in a rotary compressor assumed not to have the injection mechanism itself (graph G12). The horizontal axis represents the rotation angle (0 to 360 degrees) of the first annular piston 125S when, in FIG. 9, the position of the vane is set to 0 degrees and it is assumed that the first annular piston 125S revolves clockwise on the inner peripheral side of the first cylinder 121S. The vertical axis represents the pressure Pd [MPaG] inside the first cylinder chamber 130S. Graph G11 shows the change in the pressure inside the first cylinder chamber 130S in the rotary compressor 1 equipped with the injection mechanism of the conventional example shown in FIG. 8(b). Graph G12 shows the change in the pressure inside the first cylinder chamber when it is assumed that the conventional rotary compressor does not have the injection mechanism itself. Graph G13 shows the change in the pressure inside the injection pipe 141.

[0059] As shown in FIGS. 9(a) to 9(c), in the rotary compressor equipped with the injection mechanism of the conventional example, at the timing when the rotation angle of the first annular piston 125S is 0 degrees (between FIGS. 9(a) and 9(c)), the communication hole 302S is blocked by the first annular piston 125S, and the inflow of the gaseous refrigerant from the dead volume DV2 into the first cylinder chamber 130S does not occur.

[0060] Next, as shown in FIG. 9(a), in the rotary compressor equipped with the injection mechanism of the conventional example, at the timing (point A) when the rotation angle of the first annular piston 125S is about 40 degrees, the communication hole 302S blocked by the first annular piston 125S is opened, and the dead volume DV2 shown in FIG. 8(b) communicates with the first cylinder chamber 130S. At this time, the high-pressure gaseous refrigerant trapped in the dead volume DV2 flows into the first cylinder chamber 130S through the communication hole 302S. As a result, as shown in FIG. 10, after point A, the pressure (graph G11) inside the first cylinder chamber 130S in the rotary compressor equipped with the injection mechanism of the conventional example rises compared to the pressure (graph G12) inside the first cylinder chamber in the comparative example rotary compressor assuming no injection mechanism. As a result, in the rotary compressor equipped with the injection mechanism of the conventional example, due to the high pressure inside the first cylinder chamber 130S, the power required to rotate the first annular piston 125S increases compared to the comparative example, and the energy efficiency of the operation of the rotary compressor 1 decreases.

[0061] As shown in FIG. 9(b), in the rotary compressor equipped with the injection mechanism of the conventional example, at the timing (point B1) when the rotation angle of the first annular piston 125S is about 130 degrees, conversely, a part of the gaseous refrigerant compressed inside the first cylinder chamber 130S begins to flow backward toward the dead volume DV2 side. Note that the gaseous refrigerant that has flowed backward from the first cylinder chamber 130S to the dead volume DV2 in a certain rotation cycle becomes the gaseous refrigerant that flows from the dead volume DV2 into the inside of the first cylinder chamber 130S in the next rotation cycle.

[0062] As shown in FIG. 9(c), in the rotary compressor equipped with the injection mechanism of the conventional example, at the timing (point C) when the rotation angle of the first annular piston 125S is about 200 degrees, the communication hole 302S that communicates the first cylinder chamber 130S and the injection pipe 141 is blocked again by the first annular piston 125S. At this point, the mutual inflow of the gaseous refrigerant between the dead volume DV2 and the first cylinder chamber 130S ends.

[0063] As described above, in the rotary compressor equipped with the injection mechanism of the conventional example shown in FIG. 8(b), as shown in FIGS. 9 and 10, between the rotation angles of the first annular piston 125S of about 40 degrees to 130 degrees, the inflow of the gaseous refrigerant from the dead volume DV2 to the first cylinder chamber 130S occurs, and between the rotation angles of the first annular piston 125S of about 130 degrees to 200 degrees, the outflow of the gaseous refrigerant from the first cylinder chamber 130S to the dead volume DV2 occurs this time. As a result, in the rotary compressor equipped with the injection mechanism of the conventional example, the power required to rotate the first annular piston 125S once increases by the area S1 shown in FIG. 10 compared to the comparative example assuming that the injection mechanism is not provided. As a result, the energy efficiency of the operation of the rotary compressor equipped with the injection mechanism of the conventional example decreases.

[0064] Next, the case of the rotary compressor 1 provided with the injection mechanism of the embodiment will be described. FIGS. 11(a) to 11(c) are a radial cross-sectional view and a cross-sectional view in a direction orthogonal to the rotary shaft 15 showing the rotation cycle of the annular piston 125 in the rotary compressor 1 provided with the injection mechanism of the embodiment. As shown in FIG. 11, communication holes 302S and 302T communicating with the injection hole 300 are formed in the intermediate partition plate 140. When performing the injection operation, the liquid refrigerant discharged from the injection pipe 141 is introduced into the first cylinder chamber 130S through the communication hole 302S and into the second cylinder chamber 130T through the communication hole 302T. FIG. 11 shows the rotation cycle of the first annular piston 125S inside the first cylinder chamber 130S when the injection operation is not performed. Note that FIG. 11(a) illustrates the state of the annular piston 125S at the timing (point A) when the rotation angle of the first annular piston 125S is about 40 degrees. FIG. 11(b) illustrates the state of the annular piston 125S at the timing (point B2) when the rotation angle of the first annular piston 125S is about 70 degrees. FIG. 11(c) illustrates the state of the annular piston 125S at the timing (point C) when the rotation angle of the first annular piston 125S is about 200 degrees.

[0065] FIG. 12 is a graph showing a comparison between the change in the pressure inside the first cylinder chamber 130S (graph G14) when injection operation is not performed (in other words, when the on-off valve connected to the injection pipe is closed) in the rotary compressor 1 equipped with the injection mechanism of the embodiment shown in FIG. 8(a), and the change in the pressure inside the first cylinder chamber in a rotary compressor assumed not to have the injection mechanism itself (graph G15). The horizontal axis represents the rotational angle (0 to 360 degrees) of the first annular piston 125S when, in FIG. 11, the position of the vane is set to 0 degrees and it is assumed that the first annular piston 125S revolves clockwise on the inner peripheral side of the first cylinder 121S. The vertical axis represents the pressure Pd [MPaG] inside the first cylinder chamber 130S. Graph G14 shows the change in the pressure inside the first cylinder chamber 130S in the rotary compressor 1 equipped with the injection mechanism of the embodiment shown in FIG. 8(a). Graph G15 shows the change in the pressure inside the first cylinder chamber when it is assumed that the rotary compressor of the embodiment does not have the injection mechanism itself. Graph G16 shows the change in the pressure inside the injection pipe 141.

[0066] As shown in FIGS. 11(a) to 11(c), in the rotary compressor 1 equipped with the injection mechanism of the embodiment, at the timing when the rotational angle of the first annular piston 125S is 0 degrees (between FIGS. 11(a) and 11(c)), the communication hole 302S is blocked by the first annular piston 125S, and the inflow of the gaseous refrigerant from the dead volume DV1 into the first cylinder chamber 130S does not occur.

[0067] Next, as shown in Fig. 11(a), in the rotary compressor 1 equipped with the injection mechanism of the embodiment, at the timing (point A) when the rotation angle of the first annular piston 125S is about 40 degrees, the communication hole 302S blocked by the first annular piston 125S is opened, and the dead volume DV1 shown in Fig. 8(a) communicates with the first cylinder chamber 130S. At this time, the high-pressure gaseous refrigerant confined in the dead volume DV1 flows into the first cylinder chamber 130S through the communication hole 302S. However, as shown in Figs. 8(a) and 12, since the volume of the dead volume DV1 is small in the injection mechanism of the embodiment, even after point A where the dead volume DV1 and the first cylinder chamber 130S communicate, the pressure (graph G14) inside the first cylinder chamber 130S in the rotary compressor 1 equipped with the injection mechanism of the embodiment is almost the same as that in the case where it is assumed that the rotary compressor 1 of the embodiment does not have an injection mechanism. The pressure (graph G15) inside the first cylinder chamber does not increase much. Therefore, the rotary compressor 1 equipped with the injection mechanism of the embodiment can suppress the increase in the pressure inside the first cylinder chamber 130S. As a result, the rotary compressor 1 equipped with the injection mechanism of the embodiment can suppress the increase in the power required to rotate the first annular piston 125S, and can suppress the decrease in the energy efficiency of the operation of the rotary compressor 1.

[0068] As shown in FIG. 11(b), in the rotary compressor 1 equipped with the injection mechanism of the embodiment, at the timing (point B2) when the rotation angle of the first annular piston 125S is about 70 degrees, a part of the gaseous refrigerant compressed inside the first cylinder chamber 130S starts to flow back toward the dead volume DV1 side. However, since the volume of the dead volume DV1 is small in the injection mechanism of the embodiment, the influence of the backflow from the first cylinder chamber 130S to the dead volume DV1 is small. Therefore, as shown in FIG. 12, even after point B2, the pressure (graph G14) inside the first cylinder chamber 130S in the rotary compressor 1 equipped with the injection mechanism of the embodiment hardly increases compared to the pressure (graph G15) inside the first cylinder chamber in the case where it is assumed that the rotary compressor 1 of the embodiment does not have an injection mechanism.

[0069] As shown in FIG. 11(c), in the rotary compressor 1 equipped with the injection mechanism of the embodiment, at the timing (point C) when the rotation angle of the first annular piston 125S is about 200 degrees, the communication hole 302S that connects the first cylinder chamber 130S and the injection pipe 141 is blocked again by the first annular piston 125S. At this point, the mutual inflow of the gaseous refrigerant between the dead volume DV1 and the first cylinder chamber 130S ends.

[0070] As described above, in the rotary compressor 1 equipped with the injection mechanism of the embodiment shown in Fig. 8(a), as shown in Figs. 11 and 12, between the rotation angle of the first annular piston 125S being about 40 degrees to 70 degrees, the inflow of the gaseous refrigerant from the dead volume DV1 to the first cylinder chamber 130S occurs, and between the rotation angle of the first annular piston 125S being about 70 degrees to 200 degrees, the outflow of the gaseous refrigerant from the first cylinder chamber 130S to the dead volume DV1 occurs this time. As a result, in the rotary compressor 1 equipped with the injection mechanism of the embodiment, the power required to rotate the first annular piston 125S once increases by the area S2 shown in Fig. 12 compared to the case where it is assumed that the rotary compressor of the embodiment does not have an injection mechanism. However, since the dead volume DV1 of the injection mechanism of the embodiment is small, the rotary compressor 1 equipped with the injection mechanism of the embodiment hardly has a decrease in the energy efficiency of the operation as a compressor.

[0071] Fig. 13 is a partial longitudinal sectional view showing the compression part of the rotary compressor 1 according to Modification 1. As shown in Fig. 13, the holding pipe 142 may be provided with a holding pipe tip 142a corresponding to the first stepped portion (first tapered portion) 304 provided in the injection hole 300. Thereby, in the rotary compressor 1 according to Modification 1, when the holding pipe 142 is inserted into the injection hole 300 and fixed, the gap between the holding pipe tip 142a and the first stepped portion (first tapered portion) 304 can be eliminated, and refrigerant leakage can be prevented.

[0072] FIG. 14 is a partial longitudinal sectional view showing a compression section of the rotary compressor 1 according to Modification 2. As shown in FIG. 14, the holding pipe 142 may be configured to hold the outer periphery of the injection introduction pipe 144 into which the injection pipe 141 is inserted in a state where the injection introduction pipe 144 for introducing the liquid refrigerant branched after passing through the outlet side of the condenser or the decompression means to the injection hole 300 and the injection pipe 141 are concerned. As in the rotary compressor 1 according to Modification 2, the liquid refrigerant may be carried to the injection hole 300 using the injection introduction pipe 144, and the injection pipe 141 formed to be thinner (for example, the outer diameter R2 is 4 mm or less) at the injection hole 300 may be used.

[0073] FIG. 15 is an exploded perspective view of the intermediate partition plate 140. As shown in FIG. 15, the intermediate partition plate 140 may be configured to be divided into two parts, a lower intermediate partition plate 140S and an upper intermediate partition plate 140T, with the injection hole 300 as a boundary in the axial direction (the vertical direction in the figure).

[0074] Thereby, in the lower intermediate partition plate 140S, the lower part of the structure (the opening 301, the large-diameter part 303, the first step part (the first tapered part) 304, the first small-diameter part 305, the second step part (the second tapered part) 306, and the second small-diameter part 307) related to the injection hole 300 can be formed by a machine tool such as an NC milling machine with high machining accuracy. Similarly, in the upper intermediate partition plate 140T, the upper part of the structure related to the injection hole 300 can be formed by an NC milling machine or the like with high machining accuracy.

[0075] When forming the intermediate partition plate 140, an injection pipe 141 connected to the holding pipe 142 is arranged on one of the intermediate partition plates (for example, the lower intermediate partition plate 140S) that forms the configuration related to the injection hole 300. Thereby, the arrangement state of the injection pipe 141 in the injection hole 300 and the like can be visually confirmed. Next, the other intermediate partition plate (for example, the upper intermediate partition plate 140T) is joined to the intermediate partition plate on which the injection pipe 141 is arranged. In this way, the intermediate partition plate 140 having an injection mechanism can be accurately formed.

[0076] FIG. 16 is an explanatory diagram for explaining the dead volume from the connection valve. FIG. 17 is an enlarged view of the dotted line portion in FIG. 16.

[0077] In FIG. 16, the connection valve position P1 is the position of the connection valve that connects the liquid refrigerant branched after passing through the outlet side of the condenser or the pressure reducing means to the injection mechanism. Therefore, as shown in FIG. 16, the volume of the injection pipe 141 (capillary) from the connection valve position P1 to the communication holes 302S and 302T corresponds to the dead volume DV10.

[0078] Here, assuming that the inner diameter of the capillary according to this embodiment is about 1 mm and the length of the capillary from the connection valve position P1 to the communication holes 302S and 302T is 160 mm, the volume (dead volume DV10) inside the capillary is 0.18 cc. When assuming that the volume inside the capillary in the conventional configuration (refer to the dead volume DV2 in FIG. 8(b)) is 5.8 cc, the dead volume in the conventional case is 32.2 times that of this embodiment.

[0079] In addition, when the gap formed between the inner peripheral surface of the first small-diameter portion 305 of the injection hole 300 and the outer peripheral surface of the injection pipe tip 141a becomes large, as shown in FIG. 12, a dead volume DV11 is generated in the portion where the refrigerant leaks to the outside of the injection pipe 141. For example, if the above gap is 50 μm or less, it is not necessary to consider the dead volume DV11 due to refrigerant leakage. However, when the gap exceeds 50 μm, it is better to consider the dead volume DV11.

[0080] Regarding this dead volume DV11, for example, it can be estimated to be about 0.42 cc. Therefore, when the above gap is larger than 50 μm, due to the dead volume DV11, the size of the overall dead volume becomes 0.42 / 0.18 = 2.33 times that of the present embodiment where the dead volume DV11 does not occur.

[0081] Since the design of the rotary compressor 1 is similar, the shape does not change significantly whether the size is increased or decreased. Therefore, when the above gap is larger than 50 μm, regardless of the size (increase or decrease) of the rotary compressor 1, the size of the overall dead volume is 2 to 2.5 times that of the present embodiment.

[0082] As described above, the embodiments have been described, but the embodiments are not limited by the foregoing content. In addition, the foregoing components include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those within the so-called equivalent range. Furthermore, the foregoing components can be combined as appropriate. Furthermore, at least one of various omissions, substitutions, and changes of the components can be made without departing from the gist of the embodiments.

[0083] In the above-described embodiment, in the two-cylinder rotary compressor, the case where the injection hole 300 is formed in the intermediate partition plate 140 has been illustrated. However, the injection hole 300 may be provided in at least one of the lower end plate 160S and the upper end plate 160T.

[0084] In the above-described embodiment, the two-cylinder rotary compressor has been described, but it may also be applied to a single-cylinder rotary compressor, a two-stage compression rotary compressor, or the like. For example, in the case of a single-cylinder rotary compressor, the injection hole 300 to which the injection pipe 141 is fixed is provided in the lower end plate 160S or the upper end plate 160T.

Description of Reference Numerals

[0085] In the above-described embodiment, the cylinder chamber 130 (first cylinder chamber 130S) of the rotary compressor 1 is formed between the cylinder 121 (first cylinder 121S) and the annular piston 125 (first annular piston 125S), and the cylinder chamber 130 is partitioned into the suction chamber 131 (first suction chamber 131S) and the compression chamber 133 (first compression chamber 133S) by the vane 127 (first vane 127S) as an example. However, the present invention is not limited thereto. For example, although not shown, it may be applied to a swing-type rotary compressor in which a piston and a vane (blade) are integrally formed.

[0086] 1... Rotary compressor 10... Compressor housing 11... Motor 12... Compression section 12S... First compression section 12T... Second compression section 15... Rotating shaft 16... Oil supply pipe 25... Accumulator 31S... First low-pressure connecting pipe 31T... Second low-pressure connecting pipe 101... First through hole 102... Second through hole 104... First suction pipe 105... Second suction pipe 107... Discharge pipe 111... Stator 112... Rotor 121S... First cylinder 121T... Second cylinder 122S... First laterally projecting portion 122T... Second laterally projecting portion 123S…Inner wall of the first cylinder 123T…Inner wall of the second cylinder 124S…First spring hole 124T…Second spring hole 125S…First annular piston 125T…Second annular piston 127S…First vane 127T…Second vane 128S…First vane groove 128T…Second vane groove 129S…First pressure introduction passage 129T…Second pressure introduction passage 130S…First cylinder chamber 130T…Second cylinder chamber 131S…First suction chamber 131T…Second suction chamber 131S…First compression chamber 131T…Second compression chamber 133S…First compression chamber 133T…Second compression chamber 135S…First suction hole 135T…Second suction hole 136…Refrigerant passage 140…Intermediate partition plate (end plate) 140a…Outer peripheral surface 140S…Lower intermediate partition plate 140T…Upper intermediate partition plate 141…Injection pipe 141a…Tip of the injection pipe 142…Holding pipe 142a…Tip of the holding pipe 142b…Tapered portion 143…Sealing member 144…Injection introduction pipe 151…Auxiliary shaft portion 152S…First eccentric portion 152T…Second eccentric portion 153…Main shaft portion 160S…Lower end plate (end plate) 160T…Upper end plate (end plate) 161S…Auxiliary bearing portion 161T…Main bearing portion 170S…Lower muffler cover 170T…Upper muffler cover 175…Through bolt 180S…Lower muffler chamber 180T…Upper muffler chamber 190S…First discharge hole 190T…Second discharge hole 200S…First discharge valve 200T…Second discharge valve 201S…First discharge valve retainer 201T…Second discharge valve retainer 252…Accumulator holder 253…Accumulator band 255…System connecting pipe 257…Bottom through hole 260S…First vane spring 260T…Second vane spring 300…Injection hole 301…Opening 302S, 302T…Communication hole 303…Large diameter part (hole side taper part) 304…First step part (first taper part, hole side taper part) 305…First small diameter part 306…Second step part (second taper part) 307…Second small diameter part 500…Intermediate partition plate DV1, DV2, DV10, DV11…Dead volume P1…Connection valve position R…Opening R1, R3, R4…Inner diameter R2…Outer diameter

Claims

1. A compressor comprising a compression unit that compresses a refrigerant, a motor that drives the compression unit, and a compressor main body container that houses the compression unit and the motor therein, wherein the compression unit is a rotary compressor having a cylinder that forms a cylinder chamber therein, a piston that revolves on the inner peripheral side of the cylinder, and an end plate that closes an end of the cylinder, wherein the end plate is formed with a communication hole that communicates with the cylinder chamber and an injection hole through which an injection pipe for conducting the refrigerant through the communication hole can be inserted, wherein the injection pipe is fixed to the injection hole via a holding pipe that holds the outer periphery of the injection pipe, and a hole-side tapered portion for positioning the holding pipe is provided on the inner peripheral surface of the injection hole, wherein a pipe-side tapered portion corresponding to the hole-side tapered portion is provided on the outer peripheral surface of the holding pipe, wherein no taper is formed on the outer peripheral surface of the injection pipe, characterizing the rotary compressor.

2. The injection hole includes a large-diameter portion through which the holding pipe can be inserted, and a small-diameter portion that is continuously formed from the large-diameter portion and is located closer to the communication hole side than the large-diameter portion and through which the injection pipe can be inserted, wherein no taper is formed on the inner peripheral surface of the small-diameter portion, characterizing the rotary compressor according to Claim 1.

3. The compression unit includes two of the cylinders, wherein the end plate is an intermediate partition plate disposed between the two cylinders, characterizing the rotary compressor according to Claim 1.

4. The intermediate partition plate is divided into two in the axial direction with the injection hole as a boundary, and after the injection pipe is disposed on one of the divided intermediate partition plates, the other divided intermediate partition plate is joined, characterizing the rotary compressor according to Claim 3.

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