WO2022157967A1

WO2022157967A1 - Scroll compressor and refrigeration cycle device with scroll compressor

Info

Publication number: WO2022157967A1
Application number: PCT/JP2021/002413
Authority: WO
Inventors: 俊貴今西; 浩平達脇
Original assignee: 三菱電機株式会社
Priority date: 2021-01-25
Filing date: 2021-01-25
Publication date: 2022-07-28
Also published as: DE112021006906T5; JPWO2022157967A1

Abstract

The scroll compressor comprises a fixed scroll in which a fixed spiral body is formed on a fixed base plate, and a swing scroll in which a swing spiral body is formed on a rocking base plate, and the compressor compresses a refrigerant in a plurality of compression chambers of a compression mechanism unit in which the fixed spiral body and the swing spiral body are combined. The fixed base plate is provided with an intermediate chamber injection port that is opened in a compression chamber with an intermediate pressure between a suction pressure and a discharge pressure, from among the plurality of compression chambers, and supplies a two-phase refrigerant or a supercritical refrigerant that is in a pressure state equal to or higher than a critical pressure, and a suction chamber injection port that opens into a suction chamber provided on the outer peripheral side of the plurality of compression chambers in the compression mechanism unit and supplies a two-phase refrigerant or a liquid refrigerant to the suction chamber.

Description

Scroll compressor and refrigeration cycle device with scroll compressor

The present disclosure relates to a scroll compressor formed with an injection port and a refrigeration cycle device provided with the scroll compressor.

Conventionally, there is known a scroll compressor in which a fixed scroll and an orbiting scroll each having a spiral body are combined to form a compression chamber (for example, see Patent Document 1). A refrigeration cycle apparatus equipped with a scroll compressor disclosed in Patent Document 1 includes an injection circuit branched from between a condenser and an expansion valve of a refrigerant circuit and connected to the scroll compressor, and an injection expansion valve provided in the injection circuit. and In the refrigeration cycle apparatus of Patent Document 1, the refrigerant in the injection circuit is decompressed by the injection expansion valve, and the decompressed liquid refrigerant is introduced into the intermediate pressure compression chamber from the intermediate chamber injection port provided in the fixed scroll. By allowing the liquid refrigerant to flow into the intermediate-pressure compression chamber in this way, the temperature of the refrigerant gas in the compression chamber is lowered, the temperature of the refrigerant discharged from the compression chamber (hereinafter referred to as the discharge temperature) is lowered, and the efficiency is increased. I'm trying

JP 2012-127222 A

In recent years, from the perspective of preventing global warming, there has been a shift from conventional HFC refrigerants to refrigerants with low GWP. Carbon dioxide and the like are candidate refrigerants that have a lower GWP than HFC refrigerants. Due to its physical properties, carbon dioxide is a refrigerant that tends to have a high operating pressure and a high discharge temperature.

In the refrigeration cycle device of Patent Document 1, the injection expansion valve supplies the liquid refrigerant after decompression into the intermediate-pressure compression chamber to lower the discharge temperature. However, when the refrigerant is a refrigerant with a high operating pressure, such as carbon dioxide, the pressure in the compression chamber generally increases, and the pressure in the compression chamber communicating with the intermediate chamber injection port also increases. When the pressure in the compression chamber communicating with the intermediate chamber injection port increases, it becomes difficult to supply the liquid refrigerant from the injection circuit to the intermediate chamber injection port. Therefore, there is a problem that the flow rate of the liquid refrigerant for lowering the discharge temperature to the specified temperature or less cannot be ensured in the injection circuit, and the discharge temperature cannot be lowered to the specified temperature or less.

The present disclosure has been made in view of such points, and a scroll compressor and a scroll that can reduce the discharge temperature by injecting refrigerant even when using carbon dioxide alone or a mixed refrigerant containing carbon dioxide as a refrigerant An object of the present invention is to provide a refrigerating cycle device equipped with a compressor.

A scroll compressor according to the present disclosure includes a fixed scroll in which a fixed scroll body is formed on a fixed base plate, and an oscillating scroll in which an oscillating scroll body is formed on an oscillating base plate. A scroll compressor for compressing a refrigerant in a plurality of compression chambers of a compression mechanism unit combined with a spiral body, wherein a fixed base plate has an intermediate pressure between the suction pressure and the discharge pressure of the plurality of compression chambers. An intermediate chamber injection port that opens to the high-pressure compression chamber and supplies two-phase refrigerant or supercritical refrigerant in a pressure state above the critical pressure to the intermediate-pressure compression chamber; a suction chamber injection port that opens into the provided suction chamber and supplies two-phase refrigerant or liquid refrigerant to the suction chamber.

A refrigeration cycle device according to the present disclosure includes a scroll compressor, a radiator, a high-pressure side pipe of a subcooling heat exchanger, a pressure reducing device, and an evaporator, which are connected to circulate the refrigerant. a configured main circuit, and an injection circuit branched from between the radiator and the pressure reducing device and connected to the scroll compressor via the injection expansion valve and the low-pressure side piping of the subcooling heat exchanger, The circuit is branched into an intermediate chamber injection circuit communicating with the intermediate chamber injection port and a suction chamber injection circuit communicating with the suction chamber injection port downstream of the low-pressure side piping of the subcooling heat exchanger. be.

According to the present disclosure, since the intermediate chamber injection port and the suction chamber injection port are provided on the fixed base plate, injection can be performed by appropriately switching the injection ports. Therefore, even if carbon dioxide alone or a mixed refrigerant containing carbon dioxide is used as the refrigerant, the discharge temperature can be lowered by injecting the refrigerant.

1 is a schematic cross-sectional view of a scroll compressor according to Embodiment 1; FIG. 2 is a schematic cross-sectional view showing a fixed scroll of the scroll compressor according to Embodiment 1; FIG. 2 is a schematic plan view of a fixed scroll of the scroll compressor according to Embodiment 1; FIG. 4 is an explanatory diagram of opening positions of an intermediate chamber injection port and a suction chamber injection port in the fixed scroll of the scroll compressor according to Embodiment 1. FIG. 1 is a refrigerant circuit diagram showing a schematic configuration of a refrigeration cycle apparatus according to Embodiment 1; FIG. 4 is a flow chart showing switching control of the injection circuit of the refrigeration cycle apparatus according to Embodiment 1. FIG. FIG. 8 is a schematic cross-sectional view of a fixed scroll of a scroll compressor according to Embodiment 2; FIG. 8 is a schematic plan view of a fixed scroll of a scroll compressor according to Embodiment 2; FIG. 9 is an explanatory diagram of opening positions of an intermediate chamber injection port and a suction chamber injection port in a fixed scroll of a scroll compressor according to Embodiment 2; FIG. 11 is an explanatory diagram of a positional relationship between a suction chamber injection port and a suction chamber in a scroll compressor according to Embodiment 3; FIG. 11 is an explanatory diagram of a positional relationship between a suction chamber injection port and a compression chamber in a scroll compressor according to Embodiment 3;

<Embodiment 1>
Embodiment 1 will be described below with reference to the drawings. Here, in the following drawings, the same reference numerals are assigned to the same or equivalent parts, and are common to the entire text of the embodiments described below. The forms of the constituent elements shown in the entire specification are merely examples, and are not limited to the forms described in the specification. Moreover, the levels of temperature, pressure, etc. are not determined in relation to absolute values, but are relatively determined by the states and operations of systems and devices.

FIG. 1 is a schematic cross-sectional view of a scroll compressor according to Embodiment 1. FIG. FIG. 1 shows an example of a so-called high pressure shell hermetic scroll compressor. 2 is a schematic cross-sectional view showing a fixed scroll of the scroll compressor according to Embodiment 1. FIG. 3 is a schematic plan view of a fixed scroll of the scroll compressor according to Embodiment 1. FIG. FIG. 4 is an explanatory diagram of opening positions of an intermediate chamber injection port and a suction chamber injection port in the fixed scroll of the scroll compressor according to Embodiment 1. FIG.

The scroll compressor 100 has a function of sucking refrigerant, compressing it, and discharging it in a state of high temperature and high pressure. As the refrigerant, carbon dioxide (CO ₂ ) alone or a mixed refrigerant containing carbon dioxide is used. The scroll compressor 100 has a configuration in which a compression mechanism portion 35 having a fixed scroll 1 and an orbiting scroll 2, a drive mechanism portion 36, and other components are housed inside a shell 8, which is a closed container forming an outer shell. have. As shown in FIG. 1, in the shell 8, the compression mechanism section 35 is arranged on the upper side, and the drive mechanism section 36 is arranged on the lower side. An oil reservoir 12 is provided below the shell 8 .

The shell 8 includes an upper shell 8a, a middle shell 8b and a lower shell 8c. The upper shell 8a and the middle shell 8b are joined by a welded portion 80. As shown in FIG. The middle shell 8b and the lower shell 8c are joined by any joining method such as welding.

A suction pipe 5 for sucking refrigerant is connected to the middle shell 8b of the shell 8. An upper shell 8a of the shell 8 is connected with a discharge pipe 13 for discharging refrigerant, an intermediate chamber injection pipe 15-1, and a suction chamber injection pipe 15-2.

Inside the shell 8, the frame 3 and the sub-frame 19 are arranged so as to face each other with the drive mechanism portion 36 interposed therebetween. The frame 3 is arranged above the drive mechanism section 36 and positioned between the drive mechanism section 36 and the compression mechanism section 35 . The subframe 19 is positioned below the drive mechanism section 36 . The frame 3 and subframe 19 are fixed to the inner peripheral surface of the shell 8 by shrink fitting, welding, or the like. A bearing portion 3b is provided in the central portion of the frame 3, and a sub-bearing 19a is provided in the central portion of the sub-frame 19. As shown in FIG. The crankshaft 4 is rotatably supported by the bearing portion 3b and the auxiliary bearing 19a.

The drive mechanism portion 36 includes the stator 7, the rotor 6 fixed to the crankshaft 4, which is rotatably disposed on the inner peripheral surface side of the stator 7, and the drive mechanism portion 36 which is vertically accommodated in the shell 8 and serves as a rotation shaft. and a crankshaft 4. The stator 7 has a function of rotationally driving the rotor 6 when energized. The outer peripheral surface of the stator 7 is fixedly supported by the shell 8 by shrink fitting or the like. The rotor 6 has a function of rotating the crankshaft 4 by being rotationally driven when the stator 7 is energized. The rotor 6 is fixed to the outer periphery of the crankshaft 4, has a permanent magnet inside, and is held with a small gap between it and the stator 7. As shown in FIG.

The crankshaft 4 has an eccentric pin portion 4a at its upper end. The eccentric pin portion 4 a is eccentric with respect to the central axis of the crankshaft 4 . The eccentric pin portion 4a is inserted into a concave bearing 2d of the orbiting scroll 2, which will be described later. The crankshaft 4 rotates as the rotor 6 rotates, causing the orbiting scroll 2 to make an eccentric orbiting motion.

An oil circuit 22 is provided inside the crankshaft 4 . An oil pump 21 is fixed to the lower side of the crankshaft 4 . The oil pump 21 is a positive displacement pump. The oil pump 21 functions to supply the refrigerating machine oil held in the oil reservoir 12 to the concave bearing 2d and the bearing portion 3b through the oil circuit 22 inside the crankshaft 4 as the crankshaft 4 rotates. there is

In addition, an Oldham ring 20 is arranged in the shell 8 to prevent the orbiting scroll 2 from rotating during the eccentric orbiting motion. The Oldham's ring 20 is disposed between the orbiting scroll 2 and the frame 3, and functions to prevent the orbiting scroll 2 from rotating on its axis and to enable the orbital movement.

The compression mechanism section 35 has a function of compressing the refrigerant sucked from the suction pipe 5 and discharging it into the high-pressure space 14 formed above in the shell 8 . The high-pressure refrigerant discharged to the high-pressure space 14 is discharged from the discharge pipe 13 to the outside of the scroll compressor 100 . The drive mechanism 36 functions to drive the orbiting scroll 2 of the compression mechanism 35 so that the compression mechanism 35 compresses the refrigerant. That is, the drive mechanism 36 drives the orbiting scroll 2 via the crankshaft 4 , thereby compressing the refrigerant in the compression mechanism 35 .

The compression mechanism section 35 has a fixed scroll 1 and an orbiting scroll 2 . As shown in FIG. 1, the orbiting scroll 2 is arranged on the lower side and the fixed scroll 1 is arranged on the upper side. The fixed scroll 1 is fixed inside the middle shell 8b of the shell 8 via the frame 3. As shown in FIG. The fixed scroll 1 has a fixed base plate 1c and a fixed spiral body 1b, which is a spiral projection formed on one surface of the fixed base plate 1c. The orbiting scroll 2 has an orbiting bed plate 2c and an orbiting spiral body 2b, which is a spiral projection formed on one surface of the orbiting bed plate 2c.

The fixed scroll 1 and the orbiting scroll 2 are mounted inside the shell 8 in a state in which the fixed spiral body 1b and the orbiting scroll body 2b are combined with each other. The fixed spiral body 1b and the oscillating spiral body 2b are formed following an involute curve. By combining the fixed spiral body 1b and the oscillating spiral body 2b, a plurality of compression chambers 9 are formed between the fixed spiral body 1b and the oscillating spiral body 2b. The plurality of compression chambers 9 are configured to have a plurality of pairs of compression chambers symmetrical with respect to the center of the compression mechanism portion 35 . In the compression mechanism portion 35, a suction chamber 3c into which the refrigerant before being taken into the plurality of compression chambers 9 flows is formed on the outer peripheral side of the plurality of compression chambers 9. As shown in FIG.

The orbiting scroll 2 is designed to perform an eccentric orbiting motion with respect to the fixed scroll 1 without rotating on its own axis. A hollow cylindrical concave bearing 2d for receiving a driving force is formed in the substantially central portion of the surface of the orbiting scroll 2 opposite to the surface on which the orbiting spiral body 2b is formed (hereinafter referred to as the thrust surface). ing. An eccentric pin portion 4a provided at the upper end of the crankshaft 4 is inserted into the concave bearing 2d.

Further, at the distal ends of the fixed spiral body 1b of the fixed scroll 1 and the oscillating spiral body 2b of the oscillating scroll 2, respectively, a tip seal member 17a and a tip seal member 17a and a tip seal member 17a are provided along the spiral direction as indicated by the black-painted portions in FIG. A seal member 17b is inserted. The tip seal member 17a and the tip seal member 17b can move back and forth in the axial direction (vertical direction in FIG. 1) within the groove portion accommodating them. As the orbiting scroll 2 performs an eccentric orbiting motion with respect to the fixed scroll 1, the tip seal member 17a comes into sliding contact with the surface (tooth bottom surface) of the orbiting base plate 2c of the orbiting scroll 2. As shown in FIG. Also, the tip seal member 17b is in sliding contact with the fixed base plate 1c surface (tooth bottom surface) of the fixed scroll 1 . As a result, radial gaps between adjacent compression chambers 9 are sealed.

A discharge port 1a is formed in the central portion of the fixed scroll 1 to discharge compressed and high-pressure refrigerant. At the outlet opening of the discharge port 1a, a plate spring valve 11 is arranged to cover the outlet opening and prevent the refrigerant from flowing backward. A valve guard 10 is provided on one end side of the valve 11 to limit the amount of lift of the valve 11 . The refrigerant compressed to a predetermined pressure in the compression chamber 9 lifts the valve 11 against its elastic force, is discharged from the discharge port 1a into the high-pressure space 14, passes through the discharge pipe 13, and exits the scroll compressor 100. It is designed to be discharged.

The fixed base plate 1c of the fixed scroll 1 is formed with an intermediate chamber injection pipe inlet hole 1E1 and a suction chamber injection pipe inlet hole 1E2 as shown in FIGS. An intermediate chamber injection pipe inlet hole 1E1 is connected to the end of an intermediate chamber injection pipe 15-1 that penetrates through the upper shell 8a of the shell 8 and is located inside the upper shell 8a. A suction chamber injection pipe 15-2 passing through the upper shell 8a of the shell 8 and positioned inside the upper shell 8a is connected to the suction chamber injection pipe inlet hole 1E2.

An intermediate chamber injection channel 40 is further formed on the fixed base plate 1c of the fixed scroll 1. As shown in FIG. 3, the intermediate chamber injection flow path 40 includes communication holes 41 and 42 communicating with the intermediate chamber injection pipe inlet hole 1E1, intermediate chamber injection ports 16-1-1 and 16-1-2, have The intermediate chamber injection ports 16-1-1 and 16-1-2 communicate with the communicating

holes

41 and 42 and open to the pair of compression chambers 9 as shown in FIG. A pair of compression chambers 9 opened by the intermediate chamber injection ports 16-1-1 and 16-1-2 are compression chambers having an intermediate pressure between the suction pressure and the discharge pressure. As a result, the refrigerant supplied from the intermediate chamber injection pipe inlet hole 1E1 flows through the communication holes 41 and 42 from the intermediate chamber injection ports 16-1-1 and 16-1-2 to the pair of intermediate pressure compression chambers 9. Supplied as injection coolant.

The intermediate chamber injection ports 16-1-1 and 16-1-2 are provided so as to open to the pair of compression chambers 9 respectively. Therefore, when the injection refrigerant is supplied, the pressures in the pair of compression chambers 9 can be made equal to each other. The number of intermediate chamber injection ports is not limited to one for each of the pair of compression chambers 9, and may be two or more. It suffices that the number of intermediate chamber injection ports opening to each of the pair of compression chambers 9 is the same. In other words, it is sufficient that the intermediate chamber injection ports are provided at least one and in the same number so as to open to each of the pair of compression chambers 9 .

In addition, although FIG. 1 shows an example in which the intermediate chamber injection passage 40 is formed by a hole formed in the fixed scroll 1, it may be formed by a pipe independent of the fixed scroll 1. Specifically, the outflow side of the pipe penetrating the shell 8 may be branched in two directions, and each branched end may communicate with the intermediate chamber injection ports 16-1-1 and 16-1-2.

In addition, the fixed base plate 1c of the fixed scroll 1 is further formed with a suction chamber injection channel 50. As shown in FIG. The suction chamber injection channel 50 is formed independently without communicating with the intermediate chamber injection channel 40 . The suction chamber injection channel 50 has, as shown in FIG. 3, a communication hole 51 communicating with the suction chamber injection pipe inlet hole 1E2, and a suction chamber injection port 16-2. The suction chamber injection port 16-2 opens into the suction chamber 3c as shown in FIG. The suction chamber injection port 16-2 is provided at a position that opens to the suction chamber 3c but does not open to the compression chamber 9 during one rotation of the orbiting scroll 2. As shown in FIG. As a result, the refrigerant supplied from the suction chamber injection pipe inlet hole 1E2 is supplied from the suction chamber injection port 16-2 to the suction chamber 3c as injection refrigerant.

Here, the diameter of the suction chamber injection port 16-2 is configured to be larger than the diameters of the intermediate chamber injection ports 16-1-1 and 16-1-2. Since the intermediate chamber injection ports 16-1-1 and 16-1-2 are formed inside the spiral body, the diameters of the intermediate chamber injection ports 16-1-1 and 16-1-2 are adjusted to the size of the diameter to prevent communication between radially adjacent compression chambers. There are restrictions. On the other hand, since the suction chamber injection port 16-2 is formed outside the spiral body, there is no such limitation, the diameter can be increased, and the injected refrigerant can efficiently flow into the suction chamber 3c. .

<Assembly of Scroll Compressor 100>
The scroll compressor 100 of Embodiment 1 is configured such that two pipes, an intermediate chamber injection pipe 15-1 and a suction chamber injection pipe 15-2, pass through the upper shell 8a and are connected to the fixed base plate 1c. In the scroll compressor 100 adopting this configuration, if a fixing structure is adopted in which the upper shell 8a and the middle shell 8b are fixed by fitting, high accuracy is required for alignment during assembly. Specifically, when the upper shell 8a and the middle shell 8b are fitted together, it is necessary to establish a positional relationship in which the two pipes passing through the upper shell 8a can be connected to exactly the two injection pipe inlet holes. It is difficult in terms of manufacturing to manufacture each member with such accuracy as to form such a positional relationship. For this reason, in the first embodiment, the upper shell 8a and the middle shell 8b are not fitted but are set to have a dimensional relationship with a gap in the radial direction at the mutual joint portion, and the welded portion 80 (see FIG. 1). It is configured to be joined by

When assembling, first, the intermediate chamber injection pipe 15-1 and the suction chamber injection pipe 15-2 are passed through the upper shell 8a. Next, the radial positions of the upper shell 8a and the fixed base plate 1c fixed to the middle shell 8b are adjusted. Specifically, the radial position of the fixed base plate 1c fixed to the upper shell 8a and the middle shell 8b is such that the end of the intermediate chamber injection pipe 15-1 is inserted into the intermediate chamber injection pipe inlet hole 1E1. to adjust. Also, the radial positions of the fixed base plate 1c fixed to the upper shell 8a and the middle shell 8b are adjusted so that the end of the suction chamber injection pipe 15-2 is inserted into the suction chamber injection pipe inlet hole 1E2. . Then, welding is performed so as to fill the gap between the upper shell 8a and the middle shell 8b. In this manner, a radial gap is provided between the upper shell 8a and the middle shell 8b, and a structure in which the position can be adjusted within the range of the gap facilitates manufacturing.

<Operation of Scroll Compressor 100>
Next, the operation of scroll compressor 100 will be briefly described.
When a power supply terminal (not shown) provided on the shell 8 is energized, torque is generated in the stator 7 and the rotor 6, causing the crankshaft 4 to rotate. As the crankshaft 4 rotates, the orbiting scroll 2 is eccentrically orbiting while its rotation is restricted by the Oldham's ring 20 . As the crankshaft 4 rotates, the compression mechanism 35 repeats a cycle of intake, compression and discharge steps.

In the suction process, the refrigerant sucked into the shell 8 from the suction pipe 5 flows into the suction chamber 3c of the compression mechanism section 35. In the compression process, the refrigerant that has flowed into the suction chamber 3 c is taken into the pair of compression chambers 9 on the outer circumference of the plurality of compression chambers 9 . The pair of compression chambers 9, which have taken in the refrigerant, move from the outer periphery toward the center as the orbiting scroll 2 moves eccentrically, thereby compressing the refrigerant. In the discharge process, the compressed refrigerant is discharged from the discharge port 1a provided in the fixed scroll 1 against the valve guard 10, and is discharged outside the shell 8 through the discharge pipe 13. As shown in FIG.

<Description of the refrigeration cycle device 200>
5 is a refrigerant circuit diagram showing a schematic configuration of a refrigeration cycle apparatus according to Embodiment 1. FIG. Arrows in FIG. 5 indicate the flow of the coolant.
The refrigeration cycle device 200 is a refrigerant circuit in which a scroll compressor 100, a radiator 101, a high-pressure side pipe 104a of a supercooling heat exchanger 104, a pressure reducing device 102, an evaporator 103, and an accumulator 100a are connected. Prepare.

The radiator 101 is, for example, a fin-tube heat exchanger that includes a pipe through which a refrigerant flows and fins through which the pipe is inserted. The radiator 101 may be a corrugated fin heat exchanger that includes a pipe through which a refrigerant flows and corrugated fins that join the pipes together. The radiator 101 has a refrigerant outflow portion through which the refrigerant flows out below the refrigerant inflow portion through which the refrigerant flows in, and heat exchange is performed between the refrigerant and the air passing through the radiator 101 while allowing the refrigerant to pass through efficiently. be able to.

The decompression device 102 expands the refrigerant. The decompression device 102 is formed of, for example, an electronic expansion valve whose degree of opening can be adjusted, or a thermal expansion valve or the like, but may be formed of a capillary tube whose degree of opening cannot be adjusted. The evaporator 103 evaporates the refrigerant expanded by the decompression device 102 . The evaporator 103 is, for example, a fin-tube heat exchanger including a pipe through which a refrigerant flows and fins inserted through the pipe.

The supercooling heat exchanger 104 includes a high-pressure side pipe 104a through which the high-pressure side refrigerant passes between the radiator 101 and the decompression device 102, and a low-pressure side refrigerant obtained by decompressing a part of the high-pressure side refrigerant by the injection expansion valve 105. and a low-pressure side pipe 104b. The supercooling heat exchanger 104 performs heat exchange between the high-pressure side refrigerant and the low-pressure side refrigerant to supercool the high-pressure side refrigerant. The injection expansion valve 105 expands the refrigerant and is composed of an electronic expansion valve whose opening degree can be adjusted.

Below, a main circuit 113 is a circuit having the scroll compressor 100, the radiator 101, the high-pressure side pipe 104a of the subcooling heat exchanger 104, the decompression device 102, the evaporator 103, and the accumulator 100a. The refrigerant that circulates through the circuit 113 is described as the main refrigerant. Although the configuration in which the main circuit 113 is provided with the accumulator 100a is shown here, the accumulator 100a can be omitted.

The refrigeration cycle device 200 further includes an injection circuit branched from between the radiator 101 and the decompression device 102 and connected to the scroll compressor 100 via the injection expansion valve 105 and the low-pressure side pipe 104b of the subcooling heat exchanger 104. 110 is provided.

The injection circuit 110 branches off into an intermediate chamber injection circuit 111 and a suction chamber injection circuit 112 downstream of the low-pressure side pipe 104b of the subcooling heat exchanger 104 . The intermediate chamber injection circuit 111 is a circuit that supplies the refrigerant after passing through the low-pressure side pipe 104b of the supercooling heat exchanger 104 to the intermediate chamber injection pipe 15-1 of the scroll compressor 100. FIG. The intermediate chamber injection circuit 111 is provided with an intermediate chamber injection on/off valve 106 for opening and closing the intermediate chamber injection circuit 111 . The suction chamber injection circuit 112 is a circuit that supplies the refrigerant after passing through the low-pressure side pipe 14b of the supercooling heat exchanger 104 to the suction chamber injection pipe 15-2 of the scroll compressor 100. FIG. The suction chamber injection circuit 112 is provided with a suction chamber injection opening/closing valve 107 that opens and closes the suction chamber injection circuit 112 .

Refrigeration cycle device 200 is filled with carbon dioxide (CO ₂ ) as a refrigerant. A mixed refrigerant containing carbon dioxide may be used as the refrigerant.

The refrigeration cycle device 200 also includes a discharge temperature sensor 120 , a pressure sensor 121 and a control device 123 . Discharge temperature sensor 120 measures the discharge temperature of the refrigerant discharged from scroll compressor 100 . The pressure sensor 121 measures the pressure of the refrigerant between the injection expansion valve 105 in the injection circuit 110 and the low pressure side pipe 104b of the subcooling heat exchanger 104 . The control device 123 controls the entire refrigeration cycle device 200 based on the measurement results of these sensors. Specifically, the control device 123 controls the opening degree of the injection expansion valve 105 based on the measurement result of the discharge temperature sensor 120 . Control device 123 also controls intermediate chamber injection opening/closing valve 106 and suction chamber injection opening/closing valve 107 based on the measurement result of pressure sensor 121 . These controls will be explained again.

The control device 123 is composed of a microprocessor unit and is equipped with a CPU, RAM, ROM, etc. Control programs and the like are stored in the ROM. The control device 123 controls the entire refrigeration cycle device 200 according to a control program. Controller 123 is not limited to a microprocessor unit. For example, the control device 123 may be configured with something that can be updated, such as firmware. Also, the control device 123 may be a program module that is executed by a command from a CPU (not shown) or the like.

Next, the refrigerant flow in the refrigeration cycle device 200 will be described.

<Flow of main refrigerant>
In the main circuit 113, the main refrigerant discharged from the scroll compressor 100 passes through the radiator 101, the high-pressure side pipe 104a of the subcooling heat exchanger 104, the pressure reducing device 102, the evaporator 103, and the accumulator 100a. Return to 100.

<Flow of injection refrigerant>
A part of the main refrigerant discharged from the scroll compressor 100 and passed through the radiator 101 and the high-pressure side pipe 104 a of the supercooling heat exchanger 104 flows into the injection circuit 110 . The refrigerant that has flowed into the injection circuit 110 passes through the injection expansion valve 105 and flows into the low-pressure side pipe 104 b of the subcooling heat exchanger 104 . After passing through the low-pressure side pipe 104b of the subcooling heat exchanger 104, the refrigerant flows into the intermediate chamber injection circuit 111 or the suction chamber injection circuit 112. Refrigerant that has flowed into intermediate chamber injection circuit 111 is supplied from intermediate chamber injection ports 16-1-1 and 16-1-2 of scroll compressor 100 to a pair of intermediate pressure compression chambers 9 . The refrigerant that has flowed into the suction chamber injection circuit 112 is supplied from the suction chamber injection port 16-2 of the scroll compressor 100 to the suction chamber 3c.

<Injection operation>
In operation with a large differential pressure between high pressure and low pressure (hereinafter referred to as high compression ratio operation), the temperature of the refrigerant discharged from the discharge pipe 13 becomes high. The refrigeration cycle device 200 performs an injection operation using the injection circuit 110 in order to lower the discharge temperature. The injection operation includes intermediate chamber injection using the intermediate chamber injection circuit 111 and suction chamber injection using the suction chamber injection circuit 112 .

<Intermediate Chamber Injection>
In the intermediate chamber injection, a two-phase refrigerant of liquid and gas or a supercritical refrigerant is supplied from the intermediate chamber injection circuit 111 to the intermediate pressure compression chamber 9 . A supercritical refrigerant is a refrigerant in a pressure state equal to or higher than the critical pressure. By supplying the two-phase refrigerant or supercritical refrigerant from the intermediate chamber injection circuit 111 to the intermediate pressure compression chamber 9, the refrigerant in the process of being compressed in the compression chamber 9 can be cooled, and the discharge temperature can be lowered.

<Inhalation chamber injection>
In the suction chamber injection, a two-phase refrigerant of liquid and gas or liquid refrigerant is supplied from the suction chamber injection circuit 112 to the suction chamber 3c. By supplying the two-phase refrigerant or liquid refrigerant from the suction chamber injection circuit 112 to the suction chamber 3c, the refrigerant in the suction chamber 3c can be cooled, and as a result, the discharge temperature can be lowered. Note that when suction chamber injection is performed, intermediate chamber injection is not performed. Intermediate chamber injection and suction chamber injection are performed alternatively.

<Difference between intermediate chamber injection and suction chamber injection>
In the intermediate chamber injection, when the rotational speed of the crankshaft 4 is constant, the flow rate of refrigerant flowing into the evaporator 103 in the main circuit 113 is constant and the refrigerating capacity is maintained. On the other hand, in the suction chamber injection, even if the rotational speed of the crankshaft 4 is constant, the flow rate of refrigerant flowing into the evaporator 103 decreases for the following reasons, resulting in a decrease in refrigerating capacity. Therefore, in the refrigerating cycle apparatus 200, priority is first given to lowering the discharge temperature using the intermediate chamber injection.

Here, the reason why the flow rate of refrigerant flowing into the evaporator 103 decreases during suction chamber injection will be described. For comparison, first, the reason why the flow rate of refrigerant flowing into the evaporator 103 does not decrease during intermediate chamber injection will be described. Since refrigerant is supplied to the compression chamber 9 in the intermediate chamber injection, the amount of refrigerant in the compression chamber 9 increases by the amount supplied, and the amount of refrigerant discharged from the scroll compressor 100 also increases. As a result, the amount of refrigerant circulating in the main circuit 113 increases. The coolant flow into 103 does not decrease.

On the other hand, the volume of the pair of compression chambers 9 at the completion of taking in the refrigerant determined by the geometric shape of the spiral of the spiral body (out of the plurality of pairs of compression chambers 9 in FIG. The volume of chamber 9) is constant whether or not suction chamber injection is performed. Therefore, in the suction chamber injection, the amount of refrigerant drawn into the compression chamber 9 does not increase. Therefore, since the amount of refrigerant circulating in the main circuit 113 does not change, part of the refrigerant flowing through the main circuit 113 is allowed to flow into the suction chamber injection circuit 112, that is, by performing suction chamber injection, the refrigerant flows into the evaporator 103. The refrigerant flow rate to be applied is reduced.

<Switching between intermediate chamber injection and suction chamber injection>
For the above reasons, the refrigeration cycle apparatus 200 first prioritizes lowering the discharge temperature using intermediate chamber injection when the discharge temperature exceeds a predetermined temperature. However, when carbon dioxide alone or a mixed refrigerant containing carbon dioxide is used as the refrigerant, there are cases where the discharge temperature cannot be lowered to the specified temperature or less even if intermediate chamber injection is performed. This is the case where the injection circuit pressure measured by the pressure sensor 121 exceeds a predetermined pressure. Therefore, the refrigeration cycle device 200 switches the injection from the intermediate chamber injection to the suction chamber injection when the injection circuit pressure exceeds the specified pressure.

When the injection circuit pressure exceeds the specified pressure, the pressure in the intermediate pressure compression chamber 9 is also high. Therefore, the refrigerant in the intermediate chamber injection circuit 111 does not enter the intermediate pressure compression chamber 9, and therefore the discharge temperature cannot be lowered. Therefore, the refrigeration cycle device 200 switches the injection from the intermediate chamber injection to the suction chamber injection. By switching the injection from the intermediate chamber injection to the suction chamber injection, the pressure of the injection refrigerant supply destination is lowered to the pressure of the suction chamber 3c, that is, the suction pressure. Thereby, the refrigeration cycle device 200 can supply the refrigerant of the suction chamber injection circuit 112 to the suction chamber 3c, and can lower the discharge temperature.

Further, when the injection circuit pressure exceeds the specified pressure, the temperature of the refrigerant passing through the low-pressure side pipe 104b of the supercooling heat exchanger 104 increases. The degree of subcooling of the main refrigerant cannot be increased. Therefore, in the first embodiment, when the injection circuit pressure exceeds the specified pressure, the injection is switched from the intermediate chamber injection to the suction chamber injection, and the opening degree of the injection expansion valve 105 is reduced. By narrowing the opening of the injection expansion valve 105, the temperature of the refrigerant passing through the low-pressure side pipe 104b of the supercooling heat exchanger 104 can be lowered. Cooling can be increased.

A specific control flow of switching control of the injection circuit 110 will be described below.

6 is a flowchart showing switching control of the injection circuit of the refrigeration cycle apparatus according to Embodiment 1. FIG.
The control device 123 determines whether or not the discharge temperature measured by the discharge temperature sensor 120 exceeds a specified temperature (step S1). When the discharge temperature exceeds the specified temperature (YES in step S1), the control device 123 first opens the intermediate chamber injection opening/closing valve 106 fully and the suction chamber injection opening/closing valve 107 in order to reduce the discharge temperature by the intermediate chamber injection. is fully closed (step S2). That is, the control device 123 switches the downstream circuit of the injection circuit 110 to the intermediate chamber injection circuit 111 . Then, the control device 123 opens the injection expansion valve 105 so that the discharge temperature becomes equal to or lower than the specified temperature (step S3), and starts intermediate chamber injection. Subsequently, the control device 123 determines whether or not the injection circuit pressure measured by the pressure sensor 121 is equal to or lower than the predetermined pressure (step S4).

When the injection circuit pressure is equal to or lower than the specified pressure (YES in step S4), the control device 123 determines whether the discharge temperature has dropped below the specified temperature due to the start of intermediate chamber injection (step S5). In step S5, if the discharge temperature is lower than the prescribed temperature (YES in step S5), the controller 123 returns to step S1. On the other hand, if the discharge temperature has not dropped below the specified temperature (NO in step S5), the control device 123 returns to step S3 and repeats the processing of steps S3 to S5. That is, in steps S3 to S5, while the injection circuit pressure is below a specified pressure, the injection expansion valve 105 is opened, for example, by a specified degree of opening, and the intermediate chamber injection is performed until the discharge temperature becomes below the specified temperature.

When the injection circuit pressure exceeds the specified pressure (NO in step S4) while the discharge temperature does not drop below the specified temperature while the processing of steps S3 to S5 is being repeatedly performed, the control device 123 causes the injection to be interrupted. Switch from chamber injection to inhalation injection. Specifically, the control device 123 fully closes the intermediate chamber injection on/off valve 106 and fully opens the suction chamber injection on/off valve 107 (step S6). That is, the control device 123 switches the downstream circuit of the injection circuit 110 to the suction chamber injection circuit 112 . Then, the control device 123 throttles the injection expansion valve 105 by, for example, a specified degree of opening (step S7).

The control device 123 determines whether the discharge temperature has dropped below the specified temperature by throttling the injection expansion valve 105 (step S8). If the discharge temperature has not dropped below the specified temperature (NO in step S8), step S4 back to That is, in steps S4 and steps S6 to S8, while the injection circuit pressure exceeds the specified pressure, the injection expansion valve 105 is throttled, for example, by a specified opening, and the suction chamber injection is continued until the discharge temperature becomes equal to or lower than the specified temperature. conduct. Then, when the ejection temperature drops to the specified temperature or less (YES in step S8), the process returns to step S1 and the above processing is repeated.

The refrigeration cycle device 200 performs the above processing and appropriately switches between the intermediate injection and the suction injection, so that the discharge temperature is lowered to a specified temperature or less even when a single carbon dioxide refrigerant or a mixed refrigerant containing carbon dioxide is used as the refrigerant. can be made

<Effect of Embodiment 1>
The scroll compressor 100 of Embodiment 1 is open to the intermediate pressure compression chamber 9 between the suction pressure and the discharge pressure among the plurality of compression chambers 9, and is in a two-phase refrigerant or a pressure state equal to or higher than the critical pressure. Intermediate chamber injection ports 16-1-1 and 16-1-2 that supply supercritical refrigerant to intermediate-pressure compression chambers; A suction chamber injection port 16-2 that opens to the suction chamber and supplies two-phase refrigerant or liquid refrigerant to the suction chamber is provided on the fixed base plate 1c.

As a result, the scroll compressor 100 of Embodiment 1 can perform injection by appropriately switching the injection port. Therefore, the scroll compressor 100 of the first embodiment can reduce the discharge temperature by injecting the refrigerant even when using carbon dioxide alone or a mixed refrigerant containing carbon dioxide as the refrigerant.

By the way, conventionally, there is a scroll compressor in which the injection pipe is connected to the suction pipe and the injection refrigerant is supplied from the suction pipe into the shell. In this conventional scroll compressor, the liquid refrigerant of the two-phase refrigerant used as the injection refrigerant may drop into the oil reservoir due to its own weight without being taken into the compression mechanism, diluting the refrigerating machine oil in the oil reservoir. When the refrigerating machine oil is diluted with the liquid refrigerant, the viscosity of the refrigerating machine oil supplied to the bearing portion is lowered, and the reliability of the bearing portion is lowered.

In order to improve this, if an injection pipe is connected to the intake side of the accumulator, the refrigeration capacity will be greatly reduced for the following reasons. The injection refrigerant from the injection pipe is first sucked into the accumulator. Therefore, the liquid refrigerant of the two-phase refrigerant used as the injection refrigerant accumulates in the accumulator, and only the gas refrigerant is supplied to the scroll compressor as the injection refrigerant. In this case, it is necessary to lower the temperature of the refrigerant taken into the scroll compressor only by the sensible heat of the gas refrigerant, which requires a large amount of refrigerant flow. descend.

In contrast, in the scroll compressor 100 of Embodiment 1, the gas refrigerant in the suction chamber 3c can be cooled by the latent heat and sensible heat of the liquid refrigerant by directly supplying the injection refrigerant to the suction chamber 3c. . Therefore, the scroll compressor 100 of Embodiment 1 can lower the discharge temperature with a smaller injection flow rate than the conventional scroll compressor. Therefore, the scroll compressor 100 of Embodiment 1 can prevent a decrease in refrigerating capacity due to suction chamber injection more effectively than the conventional scroll compressor. Therefore, the scroll compressor 100 of Embodiment 1 does not need to increase the compressor frequency in order to secure the required refrigerating capacity, and can also suppress an increase in power consumption.

In addition, since the scroll compressor 100 of Embodiment 1 supplies the injection refrigerant directly to the suction chamber 3c, there is little possibility that the liquid refrigerant will drop into the oil reservoir 12 and dilute the oil. Therefore, the scroll compressor 100 of Embodiment 1 can suppress deterioration of the reliability of the compressor.

<Embodiment 2>
In Embodiment 1, there is one suction chamber injection port, but in Embodiment 2, there are two suction chamber injection ports. Hereinafter, the second embodiment will be described with a focus on the configuration different from the first embodiment, and the configurations not described in the second embodiment are the same as those in the first embodiment.

FIG. 7 is a schematic cross-sectional view of a fixed scroll of a scroll compressor according to Embodiment 2. FIG. 8 is a schematic plan view of a fixed scroll of a scroll compressor according to Embodiment 2. FIG. FIG. 9 is an explanatory diagram of the opening positions of the intermediate chamber injection port and the suction chamber injection port in the fixed scroll of the scroll compressor according to Embodiment 2. FIG.

The scroll compressor 100 of the second embodiment replaces the single suction chamber injection port in the scroll compressor 100 of the first embodiment with two suction chamber injection ports 16-2-1 and 16-2-2. and The diameter of the suction chamber injection port 16-2-2 and the diameter of the suction chamber injection port 16-2-1 are the same, and are larger than the diameters of the intermediate chamber injection ports 16-1-1 and 16-1-2. It is

The suction chamber injection port 16-2-1 is located at the same position as the suction chamber injection port 16-2 of the first embodiment. The suction chamber injection port 16-2-2 is positioned symmetrically with the suction chamber injection port 16-2-1 across the center of the fixed spiral body 1b, as shown in FIG. In other words, the scroll compressor 100 of the second embodiment has a pair of suction chamber injection ports 16-2-1 and 16-2-2 across the center of the fixed spiral body 1b. The number of suction chamber injection ports is not limited to one pair, and two or more pairs may be provided.

As shown in FIG. 8, suction chamber injection flow path 50A of the second embodiment includes suction chamber injection port 16-2-2 and suction chamber injection port 16-2-2 in addition to suction chamber injection flow path 50 of the first embodiment (see FIG. 3). , and a communication hole 52 . The suction chamber injection channel 50A is formed independently without communicating with the intermediate chamber injection channel 40 .

Thus, the scroll compressor 100 of Embodiment 2 has a pair of suction chamber injection ports 16-2-1 and 16-2-2. Thereby, the scroll compressor 100 of the second embodiment can supply injection refrigerant to both of the pair of suction chambers 3c during suction chamber injection. As a result, the interiors of both of the pair of compression chambers 9 downstream of the pair of suction chambers 3c in the flow of refrigerant can be cooled evenly.

<Effect of Embodiment 2>
The scroll compressor 100 of the second embodiment can obtain the same effect as that of the first embodiment, and has more than one pair of suction chamber injection ports arranged symmetrically with respect to the center of the fixed spiral body 1b. effect can be obtained. That is, in the scroll compressor 100 of the second embodiment, by performing injection into both of the pair of suction chambers 3c, the inside of both of the pair of compression chambers 9 downstream of the pair of suction chambers 3c in the refrigerant flow is It can be cooled evenly. Therefore, the scroll compressor 100 of the second embodiment can suppress uneven thermal expansion of the compression mechanism portion 35 when only one of the pair of compression chambers 9 is cooled. If only one of the pair of compression chambers 9 is cooled and uneven thermal expansion occurs in the compression mechanism 35, only one of the compression chambers 9 contacts the tip of the spiral body and the bottom of the spiral body of the other side. may be damaged. However, in the scroll compressor 100 of Embodiment 2, since both of the pair of compression chambers 9 can be cooled, uneven thermal expansion of the compression mechanism portion 35 can be suppressed, and the inconvenience of damage as described above can be suppressed.

Further, in the scroll compressor 100 of Embodiment 2, since the liquid refrigerant can be supplied to both of the pair of suction chambers 3c, liquid refrigerant is supplied to one of the pair of compression chambers 9 downstream of the pair of suction chambers 3c in the refrigerant flow. Concerns about uneven distribution of the refrigerant can be reduced, and spiral damage due to liquid compression can be suppressed.

<Embodiment 3>
Embodiment 3 differs from Embodiment 2 in the opening position of the suction chamber injection port. The following description will focus on the configuration of the third embodiment that differs from that of the second embodiment, and the configurations not described in the third embodiment are the same as those of the second embodiment.

FIG. 10 is an explanatory diagram of the positional relationship between the suction chamber injection port and the suction chamber in the scroll compressor according to Embodiment 3. FIG. 11 is an explanatory diagram of the positional relationship between the suction chamber injection port and the compression chamber in the scroll compressor according to Embodiment 3. FIG. FIG. 11 shows a state in which the swinging spiral body 2b rotates further from the state of FIG.

In

Embodiments

1 and 2, the suction chamber injection port is provided at a position where the suction chamber injection port opens only to the suction chamber 3c during one rotation of the orbiting scroll 2 and does not open to the compression chamber 9. rice field. On the other hand, in the third embodiment, the suction chamber injection port is positioned so that it opens to the suction chamber 3c during one rotation of the orbiting scroll 2 and continues to open even after the suction chamber 3c becomes the compression chamber 9. A suction chamber injection port is provided. Specifically, the suction chamber injection ports 16-2-1a and 16-2-2a are opened to the suction chamber 3c during a part of the suction process during one rotation of the orbiting scroll 2, and the suction process is completed. However, it is provided at a position where it opens to the compression chamber 9 for a part of the period after the compression process is started. FIG. 10 shows how the suction chamber injection ports 16-2-1a and 16-2-2a open into the suction chamber 3c. FIG. 11 shows how the suction chamber injection ports 16-2-1a and 16-2-2a open into the compression chamber 9. FIG.

By providing the suction chamber injection ports 16-2-1a and 16-2-2a at the above positions, injection is performed not only during the suction stroke but also during a part of the compression stroke. can be cooled directly. Therefore, in the suction chamber injection of the third embodiment, compared with the suction chamber injection of the first and second embodiments in which injection is performed only into the suction chamber 3c, the discharge temperature can be efficiently adjusted to the prescribed temperature with a smaller injection flow rate. can be lowered to

<Effect of Embodiment 3>
The scroll compressor 100 of Embodiment 3 can obtain the same effects as those of

Embodiments

1 and 2, as well as the following effects. In the scroll compressor 100 of the third embodiment, the suction chamber injection ports 16-2-1a and 16-2-2a are opened to the suction chamber 3c during a part of the suction stroke during one rotation of the orbiting scroll 2 and , is provided at a position open to the compression chamber 9 even for a part of the period after the suction stroke is completed and the compression stroke is started. Therefore, in the scroll compressor 100 of Embodiment 3, injection is performed not only during the suction stroke but also during a part of the period after the start of the compression stroke. The temperature can be lowered to below the specified temperature.

Further, in the scroll compressor 100 of Embodiment 3, injection refrigerant is supplied to the compression chambers 9, so the flow rate of refrigerant discharged from the scroll compressor 100 increases. As the flow rate of refrigerant discharged from the scroll compressor 100 increases, the amount of refrigerant flowing into the evaporator 103 increases. Therefore, in the scroll compressor 100 of the third embodiment, even when the injection is switched from the intermediate chamber injection to the suction chamber injection of the third embodiment, it is possible to prevent the refrigerating capacity from decreasing. Further, in the suction chamber injection of Embodiment 3, the refrigerant in the compression process can be directly cooled. Therefore, the suction chamber injection of the third embodiment lowers the discharge temperature to the specified temperature with a smaller injection flow rate than the suction chamber injection of the first and second embodiments, in which injection is performed only into the suction chamber 3c. be able to.

By the way, the intermediate chamber injection ports 16-1-1 and 16-1-2 open to the compression chamber 9 which is in the middle of the compression process and has an intermediate pressure inside. On the other hand, the suction chamber injection ports 16-2-1a and 16-2-2a open to the compression chamber 9 in the first half of the compression stroke. Therefore, the pressure in the suction chamber injection ports 16-2-1a and 16-2-2a is lower than the pressure in the intermediate chamber injection ports 16-1-1 and 16-1-2, suppressing the pressure rise. .

In addition, in the third embodiment, an example of a configuration with two suction chamber injection ports was shown, but a configuration with one suction chamber injection port may also be used. In other words, in a structure having one suction chamber injection port, the position of the suction chamber injection port may be provided at a position that opens not only to the suction chamber 3c but also to the compression chamber 9 for a part of the period from the start of the compression stroke. good.

1 Fixed scroll 1E1 Intermediate chamber injection pipe inlet hole 1E2 Suction chamber injection pipe inlet hole 1a Discharge port 1b Fixed spiral body 1c Fixed base plate 2 Oscillating scroll 2b Oscillating spiral body 2c Oscillating bedplate , 2d concave bearing, 3 frame, 3b bearing part, 3c suction chamber, 4 crankshaft, 4a eccentric pin part, 5 suction pipe, 6 rotor, 7 stator, 8 shell, 8a upper shell, 8b middle shell, 8c lower shell, 9 Compression chamber, 10 Valve retainer, 11 Valve, 12 Oil reservoir, 13 Discharge pipe, 14 High pressure space, 15-1 Intermediate chamber injection pipe, 15-2 Suction chamber injection pipe, 16-1-1 Intermediate chamber injection port, 16- 1-2 intermediate chamber injection port, 16-2 suction chamber injection port, 16-2-1 suction chamber injection port, 16-2-2 suction chamber injection port, 16-2-1a suction chamber injection port, 16-2- 2a suction chamber injection port, 17a tip seal member, 17b tip seal member, 19 subframe, 19a auxiliary bearing, 20 Oldham ring, 21 oil pump, 22 oil circuit, 35 compression mechanism, 36 drive mechanism, 40 intermediate chamber injection Flow path, 41 communication hole, 42 communication hole, 50 suction chamber injection flow path, 50A suction chamber injection flow path, 51 communication hole, 52 communication hole, 80 welding part, 100 scroll compressor, 100a accumulator, 101 radiator, 102 Pressure reducing device, 103 evaporator, 104 supercooling heat exchanger, 104a high pressure side pipe, 104b low pressure side pipe, 105 injection expansion valve, 106 intermediate chamber injection on/off valve, 107 suction chamber injection on/off valve, 110 injection circuit, 111 intermediate chamber Injection circuit, 112 suction chamber injection circuit, 113 main circuit, 120 discharge temperature sensor, 121 pressure sensor, 123 control device, 200 refrigeration cycle device.

Claims

A fixed scroll having a fixed spiral body formed on a fixed bed plate and an oscillating scroll having an oscillating spiral body formed on an oscillating bed plate are provided, and the fixed spiral body and the oscillating spiral body are combined. A scroll compressor that compresses refrigerant in a plurality of compression chambers of a compression mechanism,
The fixed base plate includes:
Among the plurality of compression chambers, an intermediate pressure compression chamber between a suction pressure and a discharge pressure is opened, and a two-phase refrigerant or a supercritical refrigerant in a pressure state equal to or higher than a critical pressure is supplied to the intermediate pressure compression chamber. an intermediate chamber injection port to
a suction chamber injection port that opens to a suction chamber provided on the outer peripheral side of the plurality of compression chambers in the compression mechanism and supplies two-phase refrigerant or liquid refrigerant to the suction chamber;
scroll compressor.
The scroll compressor according to claim 1, wherein one or more pairs of said suction chamber injection ports are provided on said fixed base plate symmetrically with respect to the center of said fixed spiral body.
The suction chamber injection port opens into the suction chamber during a partial period of the suction process during one rotation of the orbiting scroll, and during a partial period after the completion of the suction process and the start of the compression process. 3. The scroll compressor according to claim 1, wherein the scroll compressor is provided at a position opening to the compression chamber.
The plurality of compression chambers have a pair of compression chambers symmetrical about the center of the stationary spiral body, and the intermediate chamber injection port is at least one so as to open to each of the pair of compression chambers. 4. The scroll compressor according to any one of claims 1 to 3, wherein the same number of the scroll compressors are provided on the fixed base plate.
The scroll compressor according to any one of claims 1 to 4, wherein the refrigerant is carbon dioxide alone or a mixed refrigerant containing carbon dioxide.
a shell that accommodates the fixed scroll and the orbiting scroll, the shell having an upper shell; and a middle shell that is joined to the upper shell and to which the fixed scroll is fixed;
an intermediate chamber injection pipe passing through the upper shell;
a suction chamber injection pipe that penetrates the upper shell,
an end portion of the intermediate chamber injection pipe inside the upper shell is connected to an intermediate chamber injection pipe inlet hole formed in the fixed base plate in communication with the intermediate chamber injection port;
an end portion of the suction chamber injection pipe inside the upper shell is connected to an inlet hole of the suction chamber injection pipe formed in the fixed base plate in communication with the suction chamber injection port;
The scroll compressor according to any one of claims 1 to 5, wherein the upper shell and the middle shell are joined by a welded portion formed in a gap between joint portions.
A scroll compressor according to any one of claims 1 to 6, a radiator, a high-pressure side pipe of a supercooling heat exchanger, a pressure reducing device, and an evaporator, which are connected a main circuit configured to circulate the refrigerant;
an injection circuit branched from between the radiator and the decompression device and connected to the scroll compressor via an injection expansion valve and a low-pressure side pipe of the subcooling heat exchanger;
The injection circuit branches into an intermediate chamber injection circuit communicating with the intermediate chamber injection port and a suction chamber injection circuit communicating with the suction chamber injection port downstream of the low-pressure side pipe of the subcooling heat exchanger. refrigeration cycle equipment.
a pressure sensor for measuring the injection circuit pressure between the injection expansion valve and the low-pressure side pipe of the subcooling heat exchanger in the injection circuit;
a control device that switches a circuit downstream of the injection circuit to the intermediate chamber injection circuit or the suction chamber injection circuit based on the injection circuit pressure measured by the pressure sensor;
The control device switches the circuit downstream of the injection circuit to the intermediate chamber injection circuit when the injection circuit pressure is less than or equal to a predetermined pressure, and when the injection circuit pressure exceeds the specified pressure, the 8. The refrigeration cycle apparatus according to claim 7, wherein a circuit on the downstream side of the injection circuit is switched to the suction chamber injection circuit.