CN103620224B - Rotary compressor - Google Patents

Abstract

The rotary compressor (100) of the present invention includes a compression mechanism (3), an engine (2), a suction path (14), a communication path (16) and an on-off valve (32) as a control mechanism (30), and is set There is an internal space (28) separated from the interior of the airtight container (1) and the working chamber (25), a first check valve (35a) preventing refrigerant from flowing from the internal space (28) to the working chamber (25), and preventing The refrigerant flows from the inside of the airtight container (1) to the second check valve (35b) of the inner space (28). When the on-off valve (32) is opened, the volume of the working chamber (25) decreases, and the first The check valve (35a) is opened, and the pressure of the working chamber (25) does not rise. At this time, the rotary compressor (100) operates at substantially zero suction volume. When the on-off valve (32) is closed, the rotary compressor (100) The machine (100) operates at a normal suction volume.

Description

rotary compressor

technical field

This invention relates to rotary compressors.

Background technique

The motor of the compressor is usually controlled by an inverter and a microcomputer. If the rotation speed of the engine is reduced, a refrigeration cycle device (refrigeration cycle device) using a compressor can be operated at a capacity sufficiently lower than the rated capacity. Patent Document 1 and Patent Document 2 provide a technique for operating a refrigeration cycle apparatus at a low capacity by a method different from inverter control.

FIG. 8 is a partial cross-sectional configuration diagram of the compressor disclosed in Patent Document 1. As shown in FIG. The compressor 601 has a partition vane (vane) 615 , a partition vane spring 616 , a discharge port 617 , a discharge pipe 618 , and an opening 619 . The partition blade 615 partitions the inside of the cylinder 608 into a low-pressure chamber and a high-pressure chamber. The opening 619 is opened in the middle of the cylinder 608 and communicates with the opening and closing mechanism 620 provided in the opening 619 . The opening and closing mechanism 620 includes a plunger 621 and a spring 622 for the plunger. In a state where high-pressure gas is not introduced into the plunger 621 from the high-pressure introduction pipe 623 , the opening 619 and the suction port 612 are connected by the bypass passage 624 .

The compressor 601 is connected to a four-way valve 625 through a discharge pipe 618 , and further connected to a use side heat exchanger 626 , a pressure reducer 627 , a heat source side heat exchanger 628 , an accumulator 611 , and a suction pipe 629 . In addition, the discharge pipe 618 is connected to the middle of the four-way valve 625 and the high-pressure introduction pipe 623 via the solenoid valve 630 . Piston 607 rotates in the direction of arrow A.

When the solenoid valve 630 is opened, the high-pressure introduction pipe 623 is introduced with high-pressure gas, so the plunger 621 overcomes the plunger spring 622 and closes the opening 610 of the cylinder 608 . At this time, most of the refrigerant sucked into the cylinder 608 through the suction port 617 is discharged to the discharge pipe 618 through the discharge port 617 .

On the other hand, when the solenoid valve 630 is closed, the differential pressure in the compressor 601 decreases, and the plunger 621 returns to the position shown in FIG. 6 by the restoring force of the plunger spring 622 . Then, when the compressor 1 is operated again, high-pressure gas is not introduced into the high-pressure introduction pipe 623 . An opening 619 provided in the middle of the cylinder 608 communicates with the suction port 612 via a bypass passage 624 . As a result, part of the refrigerant in the cylinder 608 returns to the suction port 612 through the bypass passage 624 during compression, and the refrigerant discharged from the discharge pipe 618 is greatly reduced. This enables operation at a lower capacity.

FIG. 9 is a longitudinal sectional view of the compressor described in Patent Document 2. As shown in FIG. A first discharge port 714 is formed in the cylinder body 710, and a second discharge port 723 is formed in the main bearing 720 in communication with the first discharge port 714, so that the compressed gas is discharged to the outer cover 701. The main bearing 720 is formed with a A bypass hole 722 of a bypass valve (bypass valve) 780 is provided between the outlet 714 and the second discharge port 723 , so that the compressed refrigerant returns to the suction port 712 .

When the bypass hole 722 is closed, most of the refrigerant sucked into the cylinder 710 from the suction port 712 is discharged to the housing 701 through the first discharge port 714 and the second discharge port 723 .

On the other hand, when high pressure is introduced into the bypass valve 780 to open the bypass hole 722, the refrigerant sucked into the cylinder body 710 from the suction port 712 passes through the first discharge port 714 and the bypass hole 722, and returns to the suction port. port 712, so the refrigerant will not be discharged to the housing 701. Accordingly, operation at a lower capacity can be realized.

prior art literature

patent documents

Patent Document 1: Japanese Patent Application Laid-Open No. 61-93285

Patent Document 2: Japanese PCT Publication No. 2008-509325

Contents of the invention

The technical problem to be solved by the invention

However, one method for increasing the efficiency of a refrigeration cycle plant is to increase the efficiency of the compressor. The efficiency of the compressor is largely dependent on the efficiency of the engine used. Most engines are most efficient at a speed near the rated speed (eg 60Hz). Therefore, an improvement in compressor efficiency cannot be expected by driving the engine at a low rotational speed (for example, 30 Hz) using an inverter or the like. In addition, when the refrigeration cycle device is operated at a capacity lower than the rated capacity (for example, less than 30% of the rated capacity), the vibration caused by the torque fluctuation will increase as the rotational speed of the rotary compressor decreases, and it will not be possible to operate at a low rotational speed. Lower (for example, below 20Hz) to make the rotary compressor run. As a result, the rotary compressor performs intermittent operation in which operation and stop are repeated, and the efficiency of the refrigeration cycle apparatus is greatly reduced.

In Patent Document 1, when the solenoid valve 630 is opened, high-pressure gas is introduced into the high-pressure introduction pipe 623 , so the plunger 621 overcomes the plunger spring 622 and closes the opening 619 of the cylinder 608 . However, the volume of the opening 619 becomes a dead volume (dead volume), and the efficiency of the compressor 601 decreases.

In Patent Document 2, the first discharge port 714 is formed in the cylinder 710, so when it is intended to reduce the dead volume of the discharge port, the strength of the cylinder 710 decreases, and deformation due to pressure or temperature during operation The wear or abnormal wear of the parts on each other becomes a problem. In addition, if the strength of the cylinder 710 is increased, the dead volume of the discharge port will increase, and the efficiency of the compressor will decrease. In addition, in order to form the first discharge valve that prevents the refrigerant from flowing back from the first discharge port 714 to the compression chamber, it is necessary to ensure the height of the cylinder 710 to a certain extent, especially when the refrigerant used as the working fluid is high-density refrigerant, For example, in the case of R410A or carbon dioxide, the efficiency of the compressor decreases due to an increase in mechanical loss due to an increase in the load on the shaft or blades or an increase in leakage loss during compression.

In view of the above circumstances, an object of the present invention is to provide a rotary compressor capable of exhibiting high efficiency in all performance ranges from high performance to low performance in a refrigeration cycle.

Technical solutions for problem solving

That is, the present invention provides a rotary compressor in which an engine operates a piston via a shaft, wherein the compression mechanism includes: a cylinder; the piston disposed inside the cylinder; and a housing that allows the shaft to rotate freely. The above-mentioned shaft is held by the above-mentioned method, covering the upper and lower sides of the above-mentioned cylinder, and a working chamber is formed between the inner peripheral surface of the above-mentioned cylinder; and the blade that divides the above-mentioned working chamber into a suction chamber and a compression discharge chamber, the rotary compressor It is characterized in that it includes: a closed container for storing the above-mentioned compression mechanism and the above-mentioned engine; a suction path for introducing the working fluid to be compressed into the above-mentioned suction chamber; An outlet; an internal space separated from the interior of the above-mentioned airtight container and the above-mentioned working chamber; a communication passage between the above-mentioned internal space and the above-mentioned suction path; a first passage between the above-mentioned discharge port and the above-mentioned internal space; The working fluid in the passage returns to the first check valve of the discharge port from the internal space; the second passage between the internal space and the inside of the above-mentioned closed container; the working fluid passing through the second passage is prohibited from flowing from the inside of the above-mentioned closed container. a second check valve returning to the internal space; and a control mechanism provided in the communication passage and controlling the pressure of the internal space.

Invention effect

According to the present invention, the working fluid is returned from the working chamber to the suction path using the communication passage, thereby making it possible to operate the rotary compressor with a relatively small suction volume. On the other hand, if the return of the working fluid from the working chamber to the suction path is prohibited, the rotary compressor can be operated with a relatively large suction volume, that is, a normal suction volume. In addition, when the control mechanism and the inverter are controlled to compensate for the decrease in the suction volume with an increase in the rotational speed of the engine, the suction volume is reduced instead of driving the engine at a low rotational speed. Therefore, it is possible to provide a rotary compressor capable of exhibiting high efficiency in all performance ranges from high performance to low performance of the refrigeration cycle.

In addition, according to the present invention, since there is no opening to the cylinder, it is possible to prevent a reduction in the efficiency of the compressor due to the dead volume. In addition, it is possible to ensure the strength of the cylinder and prevent wear or abnormal wear of parts due to deformation due to pressure or temperature during operation. In addition, the height of the cylinder can be reduced, so especially when a high-density refrigerant such as R410A carbon dioxide, R32, R407C, HFO-1234yf, or R134a is used as the refrigerant of the working fluid, it is possible to prevent the load on the shaft or blade from increasing. Therefore, it is possible to provide a rotary compressor capable of exhibiting high efficiency due to a large increase in mechanical loss or an increase in leakage loss during compression.

Description of drawings

Fig. 1 is a longitudinal sectional view of a rotary compressor according to a first embodiment.

Fig. 2 is a longitudinal sectional view of a rotary compressor according to a second embodiment.

3A is a control flowchart of a control unit (on-off valve) and an inverter.

3B is another control flowchart of the control unit (on-off valve) and the inverter.

4 is a graph showing the relationship between the capacity of the rotary compressor, the suction volume of the compression mechanism, the state of the on-off valve, and the rotational speed of the engine.

Fig. 5 is a graph showing the relationship between the capacity of the rotary compressor and the efficiency of the rotary compressor.

Fig. 6 is a longitudinal sectional view of a rotary compressor according to a third embodiment.

Fig. 7 is a configuration diagram of a refrigeration cycle apparatus using the rotary compressor of the present embodiment.

Fig. 8 is a partial sectional structural view of a rotary compressor used in a conventional compressor control device.

Fig. 9 is a longitudinal sectional view of the conventional variable capacity rotary compressor and the rotary compressor used in its operation method.

reference sign

1 airtight container

2 engines

3 compression mechanism

4 axis

5 cylinders

6 upper case

7 lower case

8 pistons

9 blades

12 accumulator (accumulator, accumulator)

14 suction path

16 communication channels

22 oil storage department

25 studio

28 internal space

29 outlet

30 control mechanism

32 open and close valve

34a first access

34b Second access

35a first check valve

35b second check valve

40 compressor body

42 inverter

44 Control Department

90 three-way valve

92 high voltage path

100, 200, 300 rotary compressors

detailed description

(first embodiment)

As shown in FIG. 1 , a rotary compressor 100 according to this embodiment includes a compressor main body 40 , an accumulator (accumulator, accumulator) 12 , a discharge path 11 , a suction path 14 , a communication path 16 , a control mechanism 30 , and an inverter. device 42 and control unit 44.

The compressor main body 40 includes an airtight container 1 , an engine (motor) 2 , a compression mechanism 3 and a shaft 4 . Compression mechanism 3 is disposed below airtight container 1 . The engine 2 is arranged above the compression mechanism 3 in the airtight container 1 . The compression mechanism 3 and the engine 2 are connected via a shaft 4 . A terminal 21 for supplying electric power to the engine 2 is provided on the upper portion of the airtight container 1 . At the bottom of the airtight container 1, an oil reservoir 22 for holding lubricating oil is formed. The compressor body 40 has a structure of a so-called hermetic compressor.

The discharge path 11, the suction path 14, and the communication path 16 are each constituted by a refrigerant tube.

The discharge path 11 penetrates through the upper portion of the airtight container 1 and opens inside the airtight container 1 . The discharge path 11 guides compressed working fluid (typically, refrigerant, for example) out of the compressor main body 40 . The suction path 14 has one end connected to the compression mechanism 3 and the other end connected to the accumulator 12 , and passes through the trunk of the airtight container 1 .

The suction path 14 guides refrigerant to be compressed (refrigerant to be compressed) from the accumulator 12 to the working chamber 25 of the compression mechanism 3 . The communication path 16 has one end connected to the compression mechanism 3 and the other end connected to the accumulator 12 at a position different from the suction path 14 , and passes through the trunk portion of the airtight container 1 .

The communication passage 16 returns the refrigerant once sucked into the working chamber 25 of the compression mechanism 3 to the suction passage 14 before being compressed.

The compression mechanism 3 is a positive displacement fluid mechanism, and is driven by the engine 2 to compress the refrigerant. As shown in FIG. 1 , the compression mechanism 3 includes a cylinder 5 , a piston 8 , a vane 9 , a spring 10 , an upper case (frame) 6 , and a lower case 7 . Inside the cylinder 5, a piston 8 fitted to the eccentric portion 4a of the shaft 4 is arranged. A working chamber 25 is formed between the outer peripheral surface of the piston 8 and the inner peripheral surface of the cylinder 5 . Vane grooves (not shown) are formed in the cylinder 5 . A vane 9 having a tip that contacts the outer peripheral surface of the piston 8 is housed in the vane groove. The spring 10 is arranged in the vane groove. And the blade 9 is pressed against the piston 8 .

The upper casing 6 and the lower casing 7 are respectively provided on the upper side and the lower side of the cylinder block 5 so as to sandwich the cylinder block 5 and cover it. The working chamber 25 between the cylinder 5 and the piston 8 is partitioned by the vane 9, thereby forming a working chamber 25 (suction chamber) and a working chamber 25 (compression discharge chamber). The refrigerant to be compressed is introduced into the working chamber 25 (suction chamber) through the suction path 14 . The compressed refrigerant flows out from the working chamber 25 (compression discharge chamber) through the discharge port 29 formed in the upper casing 6 . In addition, on the side opposite to the working chamber 25 of the upper casing 6, an internal space 28 separated from the inside of the airtight container 1 and the working chamber 25 is provided, and a first passage 34a is formed between the discharge port 29 and the internal space 28. , the internal space 28 communicates with the discharge port 29 . In addition, a first check valve 35 a is provided in the first passage 34 a to prevent the refrigerant from flowing from the internal space 28 to the working chamber 25 . Moreover, the 2nd passage 34b is formed between the internal space 28 and the inside of the airtight container 1, and the internal space 28 and the inside of the airtight container 1 communicate. In addition, a second check valve 35 b is provided in the second passage 34 b to prevent the refrigerant from flowing from the inside of the airtight container 1 to the internal space 28 .

Wherein, the vane 9 can also be integrated with the piston 8 . That is, the piston 8 and the vane 9 may be formed of a swing type piston (SWING PISTON TYPE), or the vane 9 and the piston 8 may be joined.

The engine 2 includes a stator 17 and a rotor 18 . The stator 17 is fixed to the inner peripheral surface of the airtight container 1 . The rotor 18 is fixed to the shaft 4 and rotates together with the shaft 4 . Driven by the engine 2 , the piston 8 moves inside the cylinder 5 . As the engine 2 , an engine capable of changing the rotational speed, such as IPMSM (Interior Permanent Magnet Synchronous Motor: Interior Permanent Magnet Synchronous Motor) and SPMSM (Surface Permanent Magnet Synchronous Motor: Surface Permanent Magnet Synchronous Motor), can be used.

The control unit 44 controls the inverter 42 to adjust the rotation speed of the engine 2 , that is, the rotation speed of the rotary compressor 100 . As the control unit 44 , a DSP (Digital Signal Processor) including an A/D conversion circuit, an input/output circuit, an arithmetic circuit, a storage device, and the like can be used.

The accumulator 12 includes an accumulator container 12a and an introduction pipe 12b. The storage container 12a has an internal space capable of holding liquid refrigerant and gas refrigerant. The introduction pipe 12b penetrates the upper part of the storage container 12a, and opens toward the inner space of the storage container 12a. The other end of the suction path 14 and the other end of the communication passage 16 are respectively connected to the accumulator 12 . The other end of the suction path 14 and the other end of the communication passage 16 pass through the bottom of the storage container 12a, extend upward from the bottom of the storage container 12a, and open in the internal space of the storage container 12a at a fixed height. That is, the communication path 16 is connected to the suction path 14 via the internal space of the accumulator 12 . In addition, in order to reliably prevent the liquid refrigerant from directly flowing from the introduction pipe 12b to the suction path 14, other components such as a buffer may be provided inside the accumulator container 12a. In addition, the communication path 16 may be directly connected to the suction path 14 or the introduction pipe 12b.

The control mechanism 30 is provided in the communication passage 16 outside the compressor main body 40 . In the present embodiment, the control mechanism 30 includes an on-off valve 32 . In addition, one end of the communication passage 16 connected to the compression mechanism 3 communicates with the internal space 28 . The control mechanism 30 changes the suction volume of the rotary compressor 100 .

When the on-off valve 32 is opened, the first check valve 35 a is opened as the volume of the working chamber 25 decreases, and the refrigerant is discharged to the outside of the working chamber 25 . The discharged refrigerant returns to the suction path 14 through the communication passage 16 . Therefore, the pressure of the working chamber 25 does not rise. At this time, since the refrigerant is not discharged from the internal space 28 into the airtight container 1 , the rotary compressor 100 operates with substantially zero suction volume.

When the on-off valve 32 is closed, the refrigerant cannot return from the working chamber 25 to the suction passage 14 through the communication passage 16 . Therefore, the compression stroke starts immediately after the suction stroke ends. At this time, the first check valve 35 a prevents the refrigerant from flowing back from the internal space 28 to the working chamber 25 , so that the pressure of the internal space 28 increases. Furthermore, when the pressure of the internal space 28 rises to a pressure higher than the pressure inside the airtight container 1 , the second check valve 35 b opens, and the refrigerant is discharged into the airtight container 1 . At this time, the rotary compressor 100 operates with a normal suction volume.

The rotary compressor 100 of this embodiment controls the inverter 42 to adjust the rotation speed of the engine 2 , that is, the rotation speed of the rotary compressor 100 . However, when the refrigeration cycle apparatus is operated with a capacity lower than the rated capacity (for example, 30% or less of the rated capacity), the vibration caused by the torque fluctuation increases with the reduction of the rotation speed of the rotary compressor 100, and furthermore, it cannot The rotary compressor 100 is operated at a low rotational speed (for example, 20 Hz or less). As a result, the rotary compressor 100 performs intermittent operation in which operation and stop are repeated, and the efficiency of the refrigeration cycle apparatus is greatly reduced.

Here, a so-called "capacity variable technology utilizing suction volume switching" (hereinafter referred to as suction volume switching technology) that bypasses a part of the refrigerant compressed by the cylinder 5 to the cylinder 5 is widely known. A technique for changing the suction volume of the working chamber 25 externally. The rotary compressor 100 of the present embodiment can realize so-called digital compressor technology as such a suction volume switching technology in which operation is performed at substantially zero suction volume by opening the on-off valve 32 and The capacity is controlled by combining the operation with the normal suction volume by closing the on-off valve 32 .

In the rotary compressor 100 of this embodiment, the on-off valve 32 is opened and closed. For example, by opening the on-off valve 32 for 5 seconds and closing it for 5 seconds, the capacity by operation for a total of 10 seconds can be set to 50%. As a result, even when the refrigeration cycle apparatus is operated with a capacity lower than the rated capacity, the rotary compressor 100 can be continuously operated, so that the refrigeration cycle apparatus can be operated with high efficiency.

In addition, in the rotary compressor 100 of the present embodiment, when the on-off valve 32 is closed to operate at a normal suction volume, since there is no opening to the cylinder 5, it is possible to prevent damage caused by the dead volume. Compressor efficiency drops. That is, in a general rotary compressor 100, the working chamber 25 between the cylinder 5 and the piston 8 is divided by the vane 9, whereby the working chamber 25 (suction chamber) and the working chamber 25 (compression discharge chamber) are formed. . The refrigerant to be compressed is introduced into the working chamber 25 (suction chamber) through the suction path 14 . Here, when there is an opening in the cylinder 5, the opening communicates with the working chamber 25 (compression discharge chamber), and the refrigerant in the working chamber 25 will be held in the opening. chamber) connected, since the pressure of the refrigerant in the opening is higher than the pressure of the refrigerant in the working chamber 25 (suction chamber), the refrigerant in the opening will flow back (counterflow) to the working chamber 25 (suction chamber). At this time, the refrigerant in the working chamber 25 (suction chamber) decreases, and the volumetric efficiency decreases. In addition, since the refrigerant in the opening is not discharged into the airtight container 1, the compression capacity is lost correspondingly, and the input of the compressor increases. This series of losses is referred to as the decrease in efficiency of the compressor due to the dead volume.

In addition, in the rotary compressor 100 of the present embodiment, when the on-off valve 32 is closed and the operation is performed at a normal suction volume, the upper casing 6 is formed with a channel for allowing the compressed working fluid to flow out from the working chamber 25 . discharge port 29 . According to this structure, since the strength of the cylinder block 5 can be ensured, it is possible to prevent wear or abnormal wear of parts due to deformation due to pressure or temperature during operation. In addition, the height of the cylinder 5 is not restricted by the structure of the check valve. As a result, when a high-density refrigerant such as R410A or carbon dioxide is used as the refrigerant of the working fluid, the height of the cylinder 5 can be kept low, so that the increase in the load on the shaft 4 or the blade 9 can be reduced. The increase of mechanical loss and the gap formed between the inner circumference of the cylinder 5 and the outer circumference of the piston 8 can prevent an increase in leakage loss during compression. As a result, it is possible to provide the rotary compressor 100 capable of exhibiting high efficiency.

In addition, in the rotary compressor 100 of this embodiment, the first check valve 35a and the second check valve 35b are formed in the end face direction when the on-off valve 32 is closed to operate at a normal suction volume. According to this structure, the refrigerant flowing out from the discharge port 29 can smoothly flow into the internal space 29 and the inside of the airtight container 1, therefore, the loss in the process of discharging the refrigerant from the working chamber 25 can be suppressed, and a high-efficiency refrigerant can be provided. Rotary compressor 100.

In addition, in the rotary compressor 100 of the present embodiment, when the on-off valve 32 is closed to operate at a normal suction volume, the cross-sectional area of the second passage 34b is configured to be larger than the cross-sectional area of the first passage 34a. According to this structure, since the 1st passage 34a opens to the cylinder 5, if the cross-sectional area of the 1st passage 34a is enlarged, the efficiency of a compressor by a dead volume will fall. On the other hand, when the cross-sectional area of the first passage 34a is reduced, due to the resistance of the refrigerant flowing from the working chamber 25 through the discharge port 29, the pressure inside the working chamber 25 rises to a pressure higher than the discharge pressure, resulting in compression power increase. Therefore, the cross-sectional area of the first passage 34a needs to be determined to maximize the efficiency of the rotary compressor 100 . However, since the second passage 34b is provided between the internal space 29 and the inside of the airtight container 1, the efficiency reduction of the compressor due to the dead volume does not occur. That is, the pressure increase in the internal space 29 is suppressed by the resistance of the refrigerant flowing out through the second passage 34 b, thereby improving the performance of the rotary compressor 100 . As a result, by setting the cross-sectional area of the second passage 34b larger than the cross-sectional area of the first passage 34a, it is possible to provide the rotary compressor 100 capable of exhibiting high efficiency.

In addition, the first check valve 35a and the second check valve 35b can be constituted by a reed valve (reed valve) including reed parts 36a, 36b and a valve stopper (valve stopper) 37a, 37b. As another type of check valve, there is a free-valve (not shown), and the free-valve includes a valve body, a guide portion, and a spring. As another type of check valve, it is also possible to include a plunger and a spring for the plunger (not shown). When the plunger and the spring for the plunger are used, they can always be opened (open), so the pressure loss that occurs in the check valve can be reduced. Here, the free valve has a characteristic of being able to reduce the pressure loss when the working fluid passes, compared with the reed valve. However, in the rotary compressor 100 of this embodiment, there is a problem that when the on-off valve 32 is closed from the open state, the valve body collides with the guide portion to generate noise, and the pressure of the internal space 29 increases until the pressure of the internal space 29 increases. High, until the valve body closes the passage. Therefore, in the rotary compressor 100 of this embodiment, it is preferable to use a reed valve.

Next, the relationship between the capacity variable technology utilizing suction volume switching and the inverter 42 that drives the engine 2 at an arbitrary rotational speed will be described.

First, a case where the refrigeration cycle apparatus is operated at 70% capacity will be described as an example.

Using "capacity variable technology using suction volume switching" (hereinafter referred to as suction volume switching technology), that is, part of the refrigerant compressed by the cylinder 5 is bypassed to the outside of the cylinder 5 to make the suction of the working chamber 25 Volume change technology. At this time, in the rotary compressor 100 of this embodiment, the on-off valve 32 is opened and closed. For example, by opening the on-off valve 32 for 3 seconds and closing it for 7 seconds, the capacity by operation for a total of 10 seconds can be set to 70%.

In this way, the opening and closing operation of the on-off valve 32 is repeated, and the capacity of the refrigeration cycle apparatus can be changed by changing the opening time and closing time during the opening and closing operation. That is, by increasing the ratio of the opening time during the repetition of the opening and closing operation of the on-off valve 32, the performance of the refrigeration cycle apparatus can be reduced.

As described above, when the capacity is controlled by the capacity variable technology based on the switching of the suction volume, it is necessary to set the time during which the rotary compressor 100 operates at substantially zero suction volume by opening the on-off valve 32 to 30%. At this time, since the rotary compressor 100 continues to operate, mechanical loss for driving the compression mechanism 3 occurs even if the power to compress the refrigerant is zero.

On the other hand, when the engine 2 is driven at an arbitrary rotational speed by the inverter 42, the capacity can be set to 70% by operating the engine 2 at a rotational speed of 70% (for example, 42 Hz) relative to the rated rotational speed (for example, 60 Hz). %. Most engines 2 are designed to exhibit the highest efficiency at a rotation speed near the rated rotation speed (for example, 60 Hz), but high efficiency can be maintained as long as it is operated at a rotation speed of about 70% (for example, 42 Hz). As a result, the refrigeration cycle apparatus can be operated with high efficiency by using the inverter 42 that drives the engine 2 at an arbitrary rotation speed.

Next, a case where the refrigeration cycle apparatus is operated at 50% capacity will be described as an example.

In the case of utilizing the so-called "capacity variable technology utilizing suction volume switching", in the rotary compressor 100 of this embodiment, the on-off valve 32 is opened and closed. For example, by opening the on-off valve 32 for 5 seconds and closing it for 5 seconds, it is possible to set the capacity by operation for a total of 10 seconds to 50%.

On the other hand, when the engine 2 is driven at an arbitrary rotational speed by the inverter 42, the capacity can be set to 50% by operating the engine 2 at a rotational speed of 50% (eg, 30 Hz) of the rated rotational speed (eg, 60 Hz). %. However, most engines 2 are designed to exhibit the highest efficiency at a rotation speed near the rated rotation speed (for example, 60 Hz), but when the engine 2 is operated at a rotation speed of about 50% (for example, 30 Hz), the efficiency drops significantly. As a result, the refrigeration cycle apparatus can be operated more efficiently by using the variable capacity technology utilizing suction volume switching.

Therefore, regarding the relationship between the capacity variable technology utilizing suction volume switching and the inverter 42 that drives the engine 2 at an arbitrary rotational speed, by selecting the one that can operate the refrigeration cycle apparatus with high efficiency, the refrigeration cycle apparatus can be operated at a high efficiency. Operate with high efficiency.

However, in the present embodiment, a distinction is made between the capacity variable technology using suction volume switching and the inverter 42 that drives the engine 2 at an arbitrary rotational speed. When operating the refrigerating cycle device at 70% capacity, the capacity variable technology using suction volume switching is selected, and when operating the refrigerating cycle device at 50% capacity, an inverter that drives the engine 2 at an arbitrary speed is selected device 42, but this embodiment is not limited thereto. Regarding the ability to control the refrigeration cycle by any of the above methods, it is preferable to select the one that can operate the refrigeration cycle apparatus with high efficiency.

(Second Embodiment)

As shown in FIG. 2 , the rotary compressor 200 of this embodiment includes a second compression mechanism 33 in addition to the compression mechanism 3 described in the first embodiment. Hereinafter, "first" is attached to the components of the compression mechanism 3 described in the first embodiment. For example, the cylinder 5 is marked as the first cylinder 5, the piston 8 is marked as the first piston 8, the vane 9 is marked as the first vane 9, the working chamber 25 is marked as the first working chamber 25, and the compression mechanism 3 Labeled as first compression mechanism 3 .

The second compression mechanism 33 includes a second cylinder 55 , a second piston 58 , a second vane 59 and a second spring 60 . The second cylinder 55 is concentrically arranged with respect to the first cylinder 5 . Inside the second cylinder 55, a second piston 58 fitted to the second eccentric portion 4b of the shaft 4 is arranged. A second working chamber 75 is formed between the outer peripheral surface of the second piston 58 and the inner peripheral surface of the second cylinder 55 . A second vane groove (not shown) is formed in the second cylinder 55 . A second vane groove 59 having a tip that contacts the second piston 58 is housed in the second vane groove. The second spring 60 is arranged in the second vane groove. Also, the second spring 60 presses the second vane 59 toward the second piston 58 . The second working chamber 75 between the second cylinder 55 and the second piston 58 is separated by the second vane 59, thereby forming a second working chamber 75 (second suction chamber) and a second working chamber 75 (second compression chamber). exhaust chamber). The refrigerant to be compressed is introduced into the second working chamber 75 (second suction chamber) through the second suction path 15 . A second discharge port 79 is formed in the upper cabinet 6 . Thus, the compressed refrigerant is introduced into the second discharge port 79 inside the airtight container 1 from the second working chamber 75 (second compression discharge chamber), and the discharge valve 35 c is provided. Accordingly, the refrigerant does not flow back into the second working chamber 75 from the inside of the sealed volume 1 .

In the first compression mechanism 3 , the refrigerant to be compressed is introduced into the first working chamber 25 (suction chamber) through the first suction path 14 . The compressed refrigerant flows out from the first working chamber 25 (compression discharge chamber) through the first discharge port 29 formed in the lower casing 7 . In addition, on the side opposite to the first working chamber 25 of the lower casing 7, an internal space 28 separated from the inside of the airtight container 1, the first working chamber 25, and the second working chamber 75 is provided. A first passage 34 a is formed between the spaces 28 , and the internal space 28 communicates with the first discharge port 29 . In addition, a first check valve 35 a is provided in the first passage 34 a to prevent the refrigerant from flowing from the internal space 28 to the first working chamber 25 . Moreover, the 2nd passage 34b is formed between the internal space 28 and the inside of the airtight container 1, and the internal space 28 and the inside of the airtight container 1 communicate. In addition, a second check valve 35 b is provided in the second passage 34 b to prevent the refrigerant from flowing from the inside of the airtight container 1 to the internal space 28 .

Here, it is preferable to place the first working chamber 25 vertically (vertically) below the second working chamber 75 . This is because only the suction refrigerant passes through the first working chamber 25 in the case of low-capacity operation, so that the temperature of the cylinder decreases. In addition, the reason is that, from the viewpoint of temperature stratification, the lower temperature of the cylinder can suppress the heat from the discharged refrigerant to the sucked refrigerant more.

In addition, the lower casing 7 is covered by a muffler (muffler) 23 having a space capable of receiving the refrigerant compressed by the first compression mechanism 3 . The flow path 26 runs through the lower casing 7 , the first cylinder 5 , the middle plate 53 , the second cylinder 55 and the upper casing 6 . As a result, the refrigerant moves from the space of the muffler 23 to the inside of the airtight container 1 .

The protruding direction of the first eccentric portion 4 a is shifted by 180 degrees from the protruding direction of the second eccentric portion 4 b. That is, the phase of the first piston 8 and the phase of the second piston 58 are shifted by 180 degrees according to the rotation angle of the shaft 4 .

The refrigerant is supplied to the first compression mechanism 3 through the first suction path 14 . The refrigerant is supplied to the second compression mechanism 33 through the second suction path 15 . The refrigerant is compressed by the first compression mechanism 3 or the second compression mechanism 33 and discharged into the airtight container 1 . The first suction path 14 and the second suction path 15 are respectively connected to the accumulator 12 . However, one of the suction paths 14 and 15 may branch (branch) from the other inside or outside the accumulator 12 .

As shown in FIG. 2 , the second compression mechanism 33 is not connected to the communication passage 16 , so the suction volume of the second compression mechanism 33 is always constant. The communication passage 16 is connected only to the first compression mechanism 3 so that only the suction volume of the first compression mechanism 3 can be changed. Thereby, the production cost of the rotary compressor 200 can be suppressed. Of course, the communication passage 16 may also be connected to the first compression mechanism 3 and the second compression mechanism 33 respectively, so that the respective suction volumes of the first compression mechanism 3 and the second compression mechanism 33 can be changed.

In this embodiment, the first compression mechanism 3 is arranged on a side away from the engine 2 , and the second compression mechanism 33 is arranged on a side close to the engine 2 . That is, the engine 2 , the second compression mechanism 33 , and the first compression mechanism 3 are arranged in sequence along the axial direction of the shaft 4 . The second compression mechanism 33 has a fixed suction volume, and therefore needs to have a higher torque than the first compression mechanism 3 that can operate with substantially zero suction volume. Therefore, when the second compression mechanism 33 is arranged on the side close to the engine 2, the load applied to the shaft 4 when the first compressor 3 is operated at substantially zero suction volume is reduced, thereby reducing the size of the upper casing. 6 and the mechanical loss of the lower casing 7, etc. In addition, when the first compression mechanism 3 capable of operating at substantially zero suction volume is arranged on the lower side, the pressure loss caused by the compressed refrigerant flowing into the inner space 28 of the airtight container 1 through the muffler 23 can be reduced. However, the positional relationship between the first compression mechanism 3 and the second compression mechanism 33 is not limited to the above relationship.

In addition, in the present embodiment, the normal suction volume of the first compression mechanism 3 is equal to the suction volume of the second compression mechanism 33 . Here, the case where the first compressor 3 is operated with substantially zero suction volume is the low volume mode, and the case where the first compression mechanism 3 is operated with the normal suction volume is the high volume mode. At this time, when the suction volume in the high volume mode of the rotary compressor 200 is V, the suction volume in the low volume mode is V/2.

Next, referring to FIG. 3A , the inverter 42 that drives the engine 2 at an arbitrary rotational speed, the control mechanism 30 (on-off valve 32 ) by the control unit 44 that controls the inverter 42 , and the control procedure of the inverter 42 will be described.

In step 1, the rotational speed of the engine 2 is adjusted according to the required capacity. Specifically, the rotation speed of the engine 2 is adjusted so that the required refrigerant flow rate can be obtained. Next, in step 2 and step 6, it is judged whether the rotation speed of the engine 2 is reduced or the rotation speed of the engine 2 is increased. When it is judged in step 2 that the process of reducing the rotational speed has been performed, the process proceeds to step 3, where it is judged whether the current rotational speed is 30 Hz or less. If the current rotational speed is below 30 Hz, then in step 4, it is judged whether the on-off valve 32 is in the closed state. When the on-off valve 32 is in the closed state, in step 5 , a process of opening the on-off valve 32 and a process of raising the rotational speed of the engine 2 to twice the current rotational speed are executed. The order of the processes in Step 5 is not particularly limited, but the rotation speed of the engine 2 can be raised substantially simultaneously with the opening of the on-off valve 32 .

On the other hand, when it is determined in step 2 that the process of increasing the rotational speed is to be performed, the process proceeds to step 7, where it is determined whether the current rotational speed is 70 Hz or higher. If the current rotational speed is above 70 Hz, then in step 8, it is judged whether the on-off valve 32 is in an open state. When the on-off valve 32 is in the open state, in step 9, a process of closing the on-off valve 32 and a process of reducing the rotational speed of the engine 2 to 1/2 times the current rotational speed are executed. The order of the processes in step 9 is not particularly limited, but the rotation speed of the engine 2 can be reduced substantially simultaneously with the closing of the on-off valve 32 .

Control is performed in accordance with the flowchart of FIG. 3A , whereby the relationship between the state of the on-off valve 32 and the rotational speed of the engine 2 has a hysteresis phenomenon as shown in FIG. 4 . According to such control, hunting of the compression mechanism 3 can be prevented.

In the rotary compressor 200 of the present embodiment, the suction volume of the compression mechanism 3 in the high volume mode in which the on-off valve 32 is closed, that is, the return of the refrigerant from the working chamber 25 to the suction passage 14 through the communication passage 16 is prohibited. for "V". During operation in the high volume mode, when the rotation speed of the engine 2 decreases from the high rotation side to below the first rotation speed (for example, 30 Hz), the control unit 44 executes processing related to the on-off valve 32 for reducing the suction volume and for Processing related to the inverter 42 to increase the rotational speed of the engine 2 . The process related to the on-off valve 32 for reducing the suction volume refers to the process of opening the on-off valve 32 . The process related to the inverter 42 for increasing the rotation speed of the engine 2 is to set the target rotation speed of the engine 2 to twice the latest rotation speed.

In addition, the control unit 44 controls the on-off valve 32 and the inverter 42 to compensate for the increase in the suction volume with the decrease in the number of revolutions of the engine 2 . The suction volume of the compression mechanism 3 in the state where the on-off valve 32 is opened, that is, in the low volume mode allowing the refrigerant to return from the working chamber 25 to the suction passage 14 through the communication passage 16, is "V/2". When the rotation speed of the engine 2 rises above the second rotation speed (for example, 70 Hz) during operation in the low volume mode, the control unit 44 executes processing related to the opening and closing valve 32 for increasing the suction volume and reducing the speed of the engine 2 . Processing related to the inverter 42 of the rotational speed. The process related to the on-off valve 32 for increasing the suction volume refers to the process of closing the on-off valve 32 . The processing related to the inverter 42 for reducing the rotation speed of the engine 2 means setting the target rotation speed of the engine 2 to 1/2 times the latest rotation speed.

As shown in FIG. 4 , when the on-off valve 32 is closed and the rotational speed of the engine 2 drops below 30 Hz, the on-off valve 32 is opened to increase the rotational speed of the engine 2 to 60 Hz. When the rotation speed of the engine 2 rises above 70 Hz with the on-off valve 32 opened, the on-off valve 32 is closed to reduce the rotation speed of the engine 2 to 35 Hz. When the rotation speed of the engine 2 is increased by opening the on-off valve 32, the rotation speed is the third rotation speed, and the rotation speed is the fourth rotation speed when the rotation speed of the engine 2 is lowered by closing the on-off valve 32, (the first rotation speed)<(the first rotation speed) Four rotational speeds), (third rotational speed)<(second rotational speed) relationship is established. For example, by setting the first rotational speed to a rotational speed of 30 Hz or less, it is possible to operate the rotary compressor 200 with a wider range of capabilities. The lower limit of the first rotational speed is not particularly limited, and is, for example, 20 Hz.

When the control mechanism 30 is controlled so that the first compression mechanism 3 operates at substantially zero suction volume, the inverter 42 is controlled to compensate for the decrease in suction volume by increasing the rotational speed of the engine 2 . Accordingly, when the refrigeration cycle apparatus is operated with a capacity lower than the rated capacity, it is not necessary to reduce the rotational speed of the engine 2 to an extremely low level. That is, the engine 2 can be driven at a rotational speed capable of exhibiting high efficiency even when the engine is operated at a low capacity. Therefore, the efficiency of the rotary compressor 200 is also improved.

Specifically, the rotary compressor 200 according to the present embodiment can exhibit high efficiency even when it is operated at a low capacity, as indicated by a solid line in FIG. 5 . In FIG. 5 , the rated capacity of the rotary compressor 200 is set to "100%". When the efficiency of the rotary compressor 200 is based on the rated capacity, the capacity to be exhibited decreases, that is, the rotational speed of the engine 2 decreases. As indicated by the dotted line, when the engine 2 is driven at a rotation speed below 50% of the rated rotation speed, the efficiency drops significantly. In the present embodiment, when a relatively low capacity is required, the operation is performed in the low volume mode of the suction volume V/2. Accordingly, the engine 2 can be driven at a rotation speed as close as possible to the rated rotation speed. Therefore, it is possible to provide the rotary compressor 200 capable of exhibiting high efficiency even in a region where the required capacity is 50% or less of the rated capacity.

In addition, it is not necessary to compensate 100% (one hundred percent) reduction in capacity of the rotary compressor 200 due to decrease in suction volume by utilizing an increase in capacity of the rotary compressor 200 due to an increase in the rotational speed of the engine 2 . For example, when the on-off valve 32 is opened to reduce the suction volume to 1/2, the capacity of the rotary compressor 200 will not change due to mode switching as long as the rotation speed of the engine 2 is doubled. However, even if the capacity of the rotary compressor 200 increases or decreases due to mode switching, there is no major problem.

In addition, it is also possible to make the heights of the first cylinder 5 and the second cylinder 55 different according to the ratio of the suction volume to be changed (should be changed), so that the normal suction volume of the first compression mechanism 3 and the second compression mechanism 33 suction volume changes. Specifically, when the suction volume of the first compression mechanism 3 is V1, and the suction volume of the second compression mechanism is V2, the suction volume VH in the high volume mode is V1+V2, and the suction volume VL in the low volume mode is V1. for V2. Generally, it is preferable that the ratio (VL/VH) of the suction volume VL in the low volume mode to the suction volume VH in the high volume mode is in the range of 0.2 to 0.8.

Consider the case where the normal suction volume of the first compression mechanism 3 and the suction volume of the second compression mechanism 33 are changed by making the heights of the first cylinder 5 and the second cylinder 55 different according to the ratio of the suction volume to be changed. Specifically, consider that when the suction volume of the first compression mechanism 3 is V1 and the suction volume of the second compression mechanism is V2, the suction volume VH in the high volume mode is V1+V2, and the suction volume in the low volume mode is The case where the volume VL is V2. At this time, when switching between the high volume mode and the low volume mode, the rotational speed of the engine 2 can be adjusted according to the ratio (VL/VH) of the suction volume VL in the low volume mode to the suction volume VH in the high volume mode. When switching from the high volume mode to the low volume mode, the rotational speed (target rotational speed) of the engine 2 is set to the rotational speed obtained by dividing the rotational speed of the engine 2 immediately before the mode switching by the ratio (VL/VH). Likewise, when switching from the low-volume mode to the high-volume mode, the rotational speed of the engine 2 is set to the rotational speed obtained by multiplying the rotational speed of the engine 2 immediately before the mode switching by the ratio (VL/VH). In this way, switching of the operation mode between the high-volume mode and the low-volume mode can be performed smoothly.

In addition, in the present embodiment, the control mechanism 30 does not have the ability to depressurize the refrigerant. The sucked refrigerant is not substantially compressed in the compression discharge chamber, but returns to the first suction path 14 through the communication passage 16 . Therefore, the drop in efficiency due to pressure loss is extremely small. However, as long as the efficiency of the rotary compressor 200 is not greatly affected, the control mechanism 30 may have the ability to depressurize the refrigerant.

Next, other control procedures of the on-off valve 32 and the inverter 42 will be described.

In the high-capacity mode, even if the rotational speed of the engine 2 is reduced to the first rotational speed (for example, 30 Hz), the flow rate of the refrigerant is still excessive, and the control unit 44 may execute the processing related to the on-off valve 32 for reducing the suction volume and Processing related to the inverter 42 for increasing the rotational speed of the engine 2 . That is, the control unit 44 determines whether or not mode switching is necessary before actually reducing the rotation speed of the engine 2 to the first rotation speed. Similarly, in the low-volume mode, even if the rotational speed of the engine 2 is raised to the second rotational speed (for example, 70 Hz), when the flow rate of the refrigerant is insufficient, the control unit 44 can also perform the operation related to the on-off valve 32 for reducing the suction volume. processing and processing related to the inverter 42 for increasing the rotational speed of the engine 2 . That is, the control unit 44 determines whether or not mode switching is necessary before actually raising the rotation speed of the engine 2 to the second rotation speed. An example of such control will be described with reference to FIG. 3B .

As shown in FIG. 3B , first, at step 11 , the required rotational speed of the engine 2 is calculated. The "required rotation speed" refers to, for example, the rotation speed for obtaining a required refrigerant flow rate. Next, in step 12, it is judged whether the required rotational speed is lower than the first rotational speed (for example, 30 Hz). When the required rotation speed is lower than the first rotation speed, in step 13, it is judged whether the on-off valve 32 is in the closed state. When the on-off valve 32 is in the closed state, in step 15, the on-off valve 32 is opened, and the rotational speed of the engine 2 is adjusted to a rotational speed capable of obtaining the required refrigerant flow. When the on-off valve 32 is in the open state, only the rotational speed of the engine 2 is adjusted in step 14 .

On the other hand, when the required rotational speed is greater than the first rotational speed, it is judged in step 16 whether the required rotational speed is above the second rotational speed (for example, 70 Hz). When the required rotation speed is higher than the second rotation speed, in step 17, it is judged whether the on-off valve 32 is in an open state. When the on-off valve 32 is in the open state, in step 18, the on-off valve 32 is closed, and the rotational speed of the engine 2 is adjusted to a rotational speed capable of obtaining the required refrigerant flow. When the on-off valve 32 is in the closed state, only the rotational speed of the engine 2 is adjusted in step 19 .

By performing the control described with reference to FIGS. 3A and 3B , the rotary compressor 100 can exhibit high efficiency even when a low capacity is required (small load) as indicated by a solid line in FIG. 5 . In FIG. 5 , the rated capacity of the rotary compressor 100 is set to "100%". When the efficiency of the rotary compressor 100 is based on the rated capacity, the efficiency of the rotary compressor 100 decreases as the capacity to be exhibited decreases, that is, the rotational speed of the engine 2 decreases. As indicated by the dotted line, when the engine 2 is driven at a rotation speed below 50% of the rated rotation speed, the efficiency drops significantly. In the present embodiment, when a relatively low capacity is required, the operation is performed in the low volume mode of the suction volume V/2. Accordingly, the engine 2 can be driven at a rotation speed as close as possible to the rated rotation speed. Therefore, it is possible to provide the rotary compressor 100 capable of exhibiting high efficiency even in a region where the required capacity is 50% or less of the rated capacity.

(third embodiment)

As shown in FIG. 6, the rotary compressor 300 of this embodiment has the control mechanism 30 of a structure different from the rotary compressor 100 of 1st Embodiment. Other structures are the same as those described in the first embodiment.

The rotary compressor 300 has a communication passage 16 , a three-way valve 90 , and a high-pressure passage 92 as the control means 30 . The communication passage 16 includes an upstream portion 16 h that communicates the three-way valve 90 with the internal space 28 and a downstream portion that communicates the three-way valve 90 with the suction path 14 . High-pressure path 92 has one end connected to three-way valve 90 and the other end connected to oil reservoir 22 . The high-pressure path 92 is a path for supplying a pressure equal to that of the compressed refrigerant to the internal space 28 . The rotary compressor 300 of the present embodiment is a so-called high-pressure shell compressor in which the compressed refrigerant fills the inside of the hermetic container 1 . Oil having a pressure substantially equal to the pressure of the compressed refrigerant is held in the oil storage portion 22 . The three-way valve 90 connects either the suction path 14 or the high-pressure path 92 to the upstream portion 16h of the communication path 16 . By controlling the three-way valve 90, the rotary compressor 300 can be operated in any one of the high-volume mode and the low-volume mode.

In the low volume mode, the three-way valve 90 is controlled so that the suction path 14 communicates with the upstream portion 16h of the communication passage 16 . At this time, as the volume of the working chamber 25 decreases, the first check valve 35 a opens, and the refrigerant is discharged to the outside of the working chamber 25 . The discharged refrigerant returns to the suction path 14 through the communication passage 16 . Therefore, the pressure of the working chamber 25 does not rise. At this time, since the refrigerant is not discharged from the internal space 28 into the airtight container 1 , the rotary compressor 300 operates with substantially zero suction volume.

In the high volume mode, the three-way valve 90 is controlled so that the high-pressure path 92 communicates with the upstream portion of the communication passage 16 . Thus, since the refrigerant cannot return from the working chamber 25 to the suction path 14 through the communication passage 16 , the pressure of the oil in the oil reservoir 22 is introduced into the internal space 28 . Therefore, the refrigerant starts the compression stroke immediately after the suction stroke is completed. At this time, the compressed refrigerant is discharged into the internal space 28 through the first passage 34a. Furthermore, when the pressure of the internal space 28 rises to a pressure higher than the pressure inside the airtight container 1 , the second check valve 35 b opens, and the refrigerant is discharged into the airtight container 1 . At this time, the rotary compressor 300 operates with a normal suction volume.

In the present embodiment, it is preferable to configure a space between the three-way valve 90 and the high-pressure path 92 with a capillary tube or the like having a relatively smaller cross-sectional area than the communication path 16 (not shown). The compressed refrigerant is discharged into the internal space 28 through the first passage 34a, but if the passage resistance of the refrigerant in the high-pressure path 92 is large, the second check valve 35b will be smoothly opened, and the refrigerant in the internal space 28 will be discharged. Discharge into the inside of the airtight container 1.

In the present embodiment, the high-pressure path 92 has one end connected (opened) to the oil reservoir 22 . For the purpose of supplying high pressure to the internal space 28 , one end of the high pressure path 92 may be connected to a certain part inside the airtight container 1 . In addition, when the rotary compressor 300 is used in the refrigeration cycle device, the high-pressure path 92 may also be connected to a high-pressure part of the refrigerant circuit (for example, a part between the rotary compressor 300 and the radiator). However, according to the present embodiment, when the internal space is closed, a sealing effect by oil can be obtained. This is preferable in view of preventing a decrease in efficiency due to refrigerant leakage.

In addition, according to the present embodiment, the three-way valve 90 is used as the control means 30, but a four-way valve may also be used. Specifically, the three ends of the four-way valve are connected to the high-pressure path 92, the upstream portion 16h of the communication passage 16 connected to the internal space 28, and the communication passage 16 connected to the suction path 14, and the remaining one end is always closed. , the same effect as that of the present embodiment can also be obtained in this way.

(application implementation)

As shown in FIG. 7 , a refrigeration cycle apparatus 500 can be constructed using the rotary compressor 100 . The refrigeration cycle device 500 includes a rotary compressor 100 , a radiator 502 , an expansion mechanism 504 and an evaporator 506 . These devices are connected by refrigerant pipes in the above order to form a refrigerant circuit. The radiator 502 includes, for example, an air-refrigerant heat exchanger for cooling the refrigerant compressed by the rotary compressor 100 . The expansion mechanism 504 includes, for example, an expansion valve for expanding the refrigerant cooled by the radiator 502 . The evaporator 506 includes, for example, an air-refrigerant heat exchanger for heating the refrigerant expanded by the expansion mechanism 504 . Instead of the rotary compressor 100 of the first embodiment, the rotary compressors 200 and 300 of the second and third embodiments may be used.

Several embodiments described in this specification can be combined with each other within the scope not departing from the gist of the present invention. For example, the effects described in the second embodiment can be obtained by combining the on-off valve 30 described in the second embodiment and the three-way valve 90 described in the third embodiment.

Industrial availability

The present invention is suitably applied to a compressor that can be used for a refrigeration cycle device such as a water heater, a hot water heater, and an air conditioner. The present invention is particularly suitable for use in compressors for air conditioning installations requiring a wide range of capabilities.

Claims (11)

1. A rotary compressor whose motor operates a piston via a shaft, wherein, The compression mechanism includes: cylinder; the piston disposed inside the cylinder; a housing for holding the shaft in a rotatable manner, covering both upper and lower sides of the cylinder, and forming a working chamber with the inner peripheral surface of the cylinder; and vanes that divide the working chamber into a suction chamber and a compression discharge chamber, The rotary compressor is characterized by including: a closed container for accommodating the compression mechanism and the engine; leading the working fluid to be compressed into the suction path in the suction chamber; a discharge port arranged in the casing and allowing the compressed working fluid to flow out from the working chamber; an interior space separated from the interior of the airtight container and the working chamber; a communication passage between the internal space and the suction path; a first passage between the discharge port and the interior space; a first check valve that prevents the working fluid passing through the first passage from returning from the internal space to the discharge port; a second passage between the interior space and the interior of the closed container; a second check valve that prohibits the working fluid passing through the second passage from returning to the inner space from the inside of the airtight container; and A control mechanism that is provided in the communication passage and controls the pressure of the internal space. 2. The rotary compressor according to claim 1, characterized in that: An on-off valve is used as the control mechanism. 3. The rotary compressor according to claim 1, characterized in that: The control means includes a three-way valve that connects any one of the suction path and the high-pressure path to the internal Spatial connection. 4. The rotary compressor according to any one of claims 1 to 3, characterized in that: The first check valve and the second check valve are formed in an end face direction of the piston. 5. The rotary compressor according to any one of claims 1 to 3, characterized in that: The cross-sectional area of the second passage is larger than the cross-sectional area of the first passage. 6. The rotary compressor according to any one of claims 1 to 3, characterized in that: The first check valve and the second check valve are constituted by reed valves. 7. The rotary compressor according to any one of claims 1 to 3, characterized in that: The second check valve is composed of a plunger and a spring for the plunger. 8. The rotary compressor according to any one of claims 1 to 3, characterized in that: When the cylinder is defined as the first cylinder, the piston is defined as the first piston, the vane is defined as the first vane, the working chamber is defined as the first working chamber, and the compression mechanism When defined as the first compression mechanism, The rotary compressor also has a second cylinder, a second piston, a second vane, and a second working chamber, and further includes a second piston driven by the motor shared with the first compression mechanism. compression mechanism, The inner space separates the inside of the airtight container from the first working chamber, and the inner space is not in communication with the second working chamber. 9. The rotary compressor of claim 8, wherein: The first working chamber is located vertically below the second working chamber. 10. The rotary compressor according to any one of claims 1 to 3, characterized in that it comprises: drive an inverter of said engine at any rotational speed; and A control unit that controls the inverter. 11. The rotary compressor according to any one of claims 1 to 3, characterized in that: The refrigerant used as the working fluid is a high-density refrigerant, such as R410A, carbon dioxide, R32, R407C, HFO-1234yf or R134a.