JP2005147562A - Two-stage compression type rotary compressor, and car air conditioner and heat pump type hot water supply apparatus using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide two-stage compression type rotary compressor avoiding reduction of durability and reliability of the compressor caused by an excessive high and low pressure difference of a high stage side compressor, by a simple control means. <P>SOLUTION: This rotary compressor has: a rotary compression mechanism part 10 making a high stage side compression element 20 suck discharge gas from a low stage side compression element 40; an electric motor 3 driving the rotary compression mechanism part 10; an intermediate pressure type sealed vessel 2 storing the electric motor 3 and the rotary compression mechanism part 10; and a pressure control valve 70 stored in a housing constituting the rotary compression mechanism part 10. The pressure control valve 70 introduces a gas refrigerant inside the sealed vessel 2 into a cylinder 21 of the high stage side compression element 20 when a discharge pressure of the low stage side compression element 40 decreases to a prescribed value or below, and shuts off the introduction of the gas refrigerant inside the sealed vessel 2 into the cylinder 21 when the discharge pressure of the low stage side compression element 40 is increased over the prescribed value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a two-stage compression rotary compressor having a rotary compression mechanism that sucks and compresses a gas refrigerant discharged from a low-stage compression element into a high-stage compression element, and a car air conditioner using the same The present invention relates to a heat pump type hot water supply apparatus.

  Conventionally, this type of two-stage compression rotary compressor, in particular, an intermediate pressure dome type two-stage compression rotary compressor configured to fill a discharge container for compression on the lower stage side into a sealed container containing a compression element or the like. The machine was configured as follows. That is, in the low-stage compression element, gas refrigerant is sucked into the cylinder from the suction port, compression is performed to the intermediate pressure by the operation of the roller and the vane, and the discharge gas refrigerant of this intermediate pressure is discharged to the discharge port and It discharged into the airtight container through the discharge silencer chamber. In the high-stage compression element, the intermediate-pressure gas refrigerant in the hermetic container is sucked into the cylinder from the suction port, and is compressed to the high-pressure side pressure by the operation of the roller and the vane. Gas refrigerant was discharged from the discharge pipe into the external refrigerant circuit through the discharge port and the discharge silencer chamber.

In addition, the discharge silencer chambers of the low-stage compression element and the high-stage compression element are provided with discharge valves for preventing the reverse flow of the refrigerant compressed in the cylinder and discharged into the discharge silencer chamber. The discharge port was closed by the discharge valve so that it could be opened and closed.
JP 2003-74997 A Japanese Patent Laid-Open No. 10-141270

Here, in the case of a heat pump refrigeration apparatus (for example, a heat pump hot water supply apparatus) using a two-stage compression rotary compressor using a refrigerant having a large high-low pressure difference, such as carbon dioxide (CO ₂ ), the first stage (low stage 9) and the second stage (higher stage) intake volume are constant and the ratio is approximately 2: 1, the compression ratio of the first stage is approximately 2, and in general, It shows such characteristics. In such an apparatus, the discharge pressure (that is, the high pressure side pressure) HP of the high stage side compression element is approximately 12 MPaG or more in the region where the outside air temperature is + 10 ° C. or higher, and the suction pressure of the high stage side compression element, that is, the low stage side compression The discharge pressure of the element was an intermediate pressure MP, which was 8 MPaG or more, and the suction pressure (ie, the low pressure side pressure) LP of the low-stage compression element was 4 MPaG or more. Therefore, the high-low pressure difference (the discharge pressure HP of the high-stage compression element and the suction pressure MP of the high-stage compression element) of the high-stage compression element in the two-stage compression rotary compressor using carbon dioxide (CO ₂ ) as the refrigerant. Difference) is 4 MPaG, and the pressure difference is the same on both the low and high stages. However, in this type of two-stage compression rotary compressor, since the compression ratio is substantially constant, the lower the outside air temperature, the lower the discharge pressure MP of the low-stage compression element. The pressure difference was even greater.

  Also, if the high-low pressure difference of the high-stage compression element increases, the pressure difference between the inside and outside of the discharge valve that opens and closes the discharge port of the high-stage compression element becomes excessive, and the discharge valve is damaged. There was a problem that the durability and reliability of the component parts in the element were lowered.

  In order to solve such a problem, a heat pump type hot water supply apparatus using carbon dioxide as a refrigerant and applying a two-stage compression rotary compressor has been used in order to enable hot water supply at a higher temperature than before. In the conventional heat pump hot water supply apparatus using the two-stage compression rotary compressor, for example, a bypass that bypasses the high-pressure gas refrigerant cooled by the high-pressure side heat exchanger to the discharge side of the low-stage compression element during hot water supply operation. A circuit was provided, and an electromagnetic opening / closing valve, a capillary tube, a three-way valve, and the like were provided in the bypass circuit. When the pressure detecting means detects that the pressure difference between the high pressure side pressure HP and the intermediate pressure MP has increased, the electromagnetic on-off valve is opened and the high pressure gas is bypassed to the discharge side of the low stage compression element. Thus, the intermediate pressure is increased by changing the ratio between the intake volume on the low stage side and the intake volume on the high stage side.

  However, in the above prior art, the pressure detection means, bypass circuit, electromagnetic on-off valve, etc. are required for the refrigerant circuit, so the refrigerant circuit becomes complicated, the hot water supply device, which is a product applied to the refrigeration apparatus, becomes larger, and the cost increases. It was the cause.

  The present invention has been made in order to solve the above-described problems of the prior art, and the durability and reliability of the compressor due to an excessively high and low pressure difference between the high-stage compressor and the simple control means. It aims at providing the two-stage compression type rotary compressor which avoided the fall of property.

  The present invention solves the above-described problem, and includes a low-stage side compression element and a high-stage side compression element, and a rotation in which discharge gas from the low-stage side compression element is sucked into the high-stage side compression element. Type compression mechanism unit, electric motor that drives the rotary type compression mechanism unit, a sealed container that houses the electric motor and the rotary type compression mechanism unit, and is filled with the discharge gas refrigerant of the low-stage compression element, and the rotary type compression mechanism And a pressure control valve housed in a housing constituting the portion, and this pressure control valve causes the gas refrigerant in the hermetic container to flow into a high stage when the discharge pressure of the low stage side compression element drops below a predetermined value. Introduced into the cylinder of the side compression element, and configured to block the introduction of the gas refrigerant in the sealed container into the cylinder when the discharge pressure of the low stage side compression element rises above a predetermined value. It is characterized by that.

  The pressure control valve includes a piston and a cylinder that slidably accommodates the piston, and the piston is opposed to the resultant pressure of the low pressure side pressure and the elastic force of the spring and the gas refrigerant pressure in the sealed container. When the discharge pressure of the low-stage side compression element drops below a predetermined value, the piston is moved in one direction in the cylinder by the resultant force, and the gas refrigerant in the sealed container is moved to the high-stage side compression element. When the discharge pressure of the low-stage compression element rises above a predetermined value, the piston is moved in the other direction by the gas refrigerant pressure in the sealed container against the resultant force when the discharge pressure of the low-stage compression element rises above a predetermined value. It is good also as what is comprised so that introduction | transduction to the cylinder of the gas refrigerant in an airtight container may be interrupted | blocked.

  In addition, a car air conditioner according to the present invention includes the above-described two-stage compression rotary compressor and uses carbon dioxide as a refrigerant.

  Moreover, the heat pump type hot water supply apparatus according to the present invention is characterized by using the above-mentioned two-stage compression rotary compressor and using carbon dioxide gas as a refrigerant.

  The two-stage compression rotary compressor according to the present invention has a gas refrigerant in the hermetic container when the discharge pressure of the low-stage compression element is reduced to a predetermined value or less by setting the pressure in the hermetic container to an intermediate pressure. Is introduced into the cylinder of the high-stage compression element, and when the discharge pressure of the low-stage compression element rises above a predetermined value, the pressure control valve that shuts off the introduction of the gas refrigerant in the sealed container into the cylinder Is housed in the housing constituting the rotary compression mechanism, so that in the refrigeration apparatus using the two-stage compression rotary compressor, a bypass circuit, an electromagnetic on-off valve, a pressure detection device, and the like are used. Therefore, the refrigeration apparatus using the two-stage compression rotary compressor can be simplified and miniaturized. In the above configuration, if the electric motor can be controlled to rotate, it is possible to adjust the capacity.

  The pressure control valve includes a piston and a cylinder that slidably accommodates the piston, and the piston includes a low pressure side pressure and a resultant force of a spring and a gas refrigerant pressure in a sealed container. When the discharge pressure of the low-stage compression element drops below a predetermined value, the piston is moved in one direction in the cylinder by the resultant force to compress the gas refrigerant in the hermetic container on the high-stage side. When the discharge pressure of the low-stage compression element rises above a predetermined value, the piston is moved in the other direction by the gas refrigerant pressure in the sealed container against the resultant force. If the pressure control valve is configured to block the introduction of the gas refrigerant in the sealed container into the cylinder, only a spring is used as the drive mechanism of the pressure control valve. It is possible to simplify the.

  In addition, the car air conditioner according to the present invention uses carbon dioxide as the refrigerant gas and uses the above-described two-stage compression rotary compressor, so that it can withstand a wide range of outside air temperature and perform heating operation.

  In addition, the hot water supply air-on according to the present invention uses carbon dioxide gas as the refrigerant gas and uses the above-described two-stage compression rotary compressor, so that hot water supply can be performed and a wide range of outside air temperature can be changed. Withstand the heat supply operation.

  Next, an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a longitudinal sectional view of a two-stage compression rotary compressor embodying the present invention, that is, an intermediate pressure dome type two-stage compression rotary compressor having a high-stage compression element and a low-stage compression element. Show.

  As shown in FIG. 1, a two-stage compression rotary compressor 1 according to the present embodiment includes a cylindrical sealed container 2 made of a steel plate, an electric motor 3 disposed above the internal space of the sealed container 2, and an electric motor 3. The rotary compression mechanism unit 10 is arranged below the rotary compression mechanism unit 10 and the pressure control valve 70 housed in the housing constituting the rotary compression mechanism unit 10.

  The hermetic container 2 includes a container body 2a that houses the rotary compression mechanism 10 of the electric motor 3, and a substantially bowl-shaped end cap (lid body) 2b that closes the upper opening of the container body 2a. Oil reservoir. A circular attachment hole 2d is formed at the center of the upper surface of the end cap 2b, and a terminal (wiring is omitted) 5 for supplying electric power to the motor 3 is attached to the attachment hole 2d.

  The electric motor 3 includes a stator 6 that is annularly attached along the inner peripheral surface of the upper space of the hermetic container 2, and a rotor 7 that is inserted inside the stator 6 with a slight space therebetween. The rotation speed can be controlled.

  The stator 6 includes a laminated body 6a in which donut-shaped electromagnetic steel plates are laminated, and a stator coil 6b wound around the teeth of the laminated body 6a by a direct winding (concentrated winding) method. Similarly to the stator 6, the rotor 7 is also formed by a laminated body 7a of electromagnetic steel plates, and a permanent magnet MG is inserted into the laminated body 7a. The rotor 7 is fixed to a rotating shaft 4 that extends in the vertical direction through the center of the electric motor 3.

The rotary compression mechanism 10 includes a high-stage compression element 20 and a low-stage compression element 40 that are driven by the rotation shaft 4 of the electric motor 3. The high-stage compression element 20 and the low-stage compression element 40 include an intermediate partition plate 60, upper and lower cylinders 21 and 41 disposed above and below the intermediate partition plate 60, and a phase difference of 180 degrees in the upper and lower cylinders 21 and 41. The upper and lower eccentric parts 22, 42 provided on the rotary shaft 4, the upper and lower rollers 23, 43 (see FIGS. 4 and 5) that are fitted to the upper and lower eccentric parts 22, 42 and rotate eccentrically, and the upper and lower rollers 23 , 43 and upper and lower vanes 24, 44 (see FIGS. 4 and 5) for dividing the upper and lower cylinders 21, 41 into a low pressure chamber side and a high pressure chamber side, respectively, an upper opening surface of the upper cylinder 21 and a lower cylinder 41 It comprises upper and lower support members 25 and 45 as a support member that closes the lower opening surface and also serves as a bearing for the rotating shaft 4.
The intermediate partition plate 60, the cylinder 21, the cylinder 41, the upper support member 25, and the lower support member 45 constitute a housing of the rotary compression mechanism unit 10 referred to in the present invention.

  The upper and lower support members 25 and 45 include suction passages 26a and 46a that communicate the suction ports 26 and 46 (see FIGS. 4 and 5) with the inside of the upper and lower cylinders 21 and 41, and recessed discharge silencer chambers 27 and 47, respectively. And are formed. The discharge silencer chambers 27 and 47 communicate with the discharge ports 29 and 49. Further, the openings of both the discharge silencing chambers 27 and 47 are respectively closed by covers. That is, the discharge silencing chamber 27 is closed by the upper cover 28, and the discharge silencing chamber 47 is closed by the lower cover 48.

  Further, an upper bearing 24 a is formed upright at the center of the upper support member 25, and a lower bearing 44 a is formed through the center of the lower support member 45. The rotating shaft 4 described above is supported by the upper bearing 24 a of the upper support member 25 and the lower bearing 44 a of the lower support member 45.

  Further, the upper cover 28 closes the upper opening of the discharge silencer chamber 27 to partition the inside of the sealed container 2 into the discharge silencer chamber 27 side and the motor 3 side. As shown in FIG. 3, the upper cover 28 is formed of a substantially donut-shaped circular steel plate in which a hole through which the upper bearing 24 a of the upper support member 25 is formed, and a peripheral portion is formed by a main bolt 67. To the upper support member 25. The front end of the main bolt 67 is screwed into the lower support member 45. As shown in FIG. 3, the upper support member 25 is provided with a discharge valve 30 of the high-stage compression element 20 that opens and closes the discharge port 29 while being positioned in the discharge silencer chamber 27. .

The lower cover 48 is made of a donut-shaped circular steel plate, and is fixed to the lower support member 45 from below by main bolts 65 at the periphery. Note that the tip of the main bolt 65 is screwed into the upper support member 25.
As shown in FIG. 2, the lower support member 45 is provided with a discharge valve 50 of the low-stage compression element 40 that opens and closes the discharge port 49 while being positioned in the discharge silencer chamber 47.

  The discharge valves 30 and 50 are made of an elastic member such as a vertically long metal plate. Further, the discharge valves 30 and 50 are fixed to the upper support member 25 or the lower support member 45 so as to be closed by elastically contacting the discharge ports 29 and 49 on the other end side with screws not shown on one end side. It is screwed.

  Further, the discharge silencer chamber 47 and the upper cover 28 in the sealed container 2 are communicated with each other through a communication passage (not shown) that is a hole penetrating the upper and lower cylinders 21 and 41 and the intermediate partition plate 60. An intermediate discharge pipe 66 is erected at the upper end of the communication passage (not shown), and is configured such that intermediate pressure refrigerant is discharged from the intermediate discharge pipe 66 into the sealed container 2.

  As shown in FIG. 1, the suction pipe 51 of the low-stage compression element 40 is attached in communication with the suction passage 46 a of the lower support member 45. Further, although not shown, the suction pipe 31 of the high-stage compression element 20 communicates with the closed container 2 above the upper cover 28 at one end and communicates with the suction passage 26a of the high-stage compression element 20 at the other end. . Further, the discharge pipe 32 of the high stage side compression element is attached so as to be taken out from the discharge silencer chamber 27 of the high stage side compression element 20.

The pressure control valve 70 is provided in the housing of the rotary compression mechanism unit 10 including the above-described intermediate partition plate 60, cylinder 21, cylinder 41, upper support member 25, lower support member 45, and the like. The pressure control valve 70 includes a cylinder 71, two upper and lower pistons 72, 73, a rod 74, communication passages 76, 77, 78, and the like.
As can be understood from FIGS. 1, 6, and 7, the cylinder 71 penetrates from the lower cylinder 41 of the rotary compression mechanism 10 to the upper surface of the upper support member 25, and the upper surface is opened into the sealed container 2. . The pistons 72 and 73 are slidably accommodated in the cylinder 71, and an intermediate pressure by the gas refrigerant in the sealed container introduced from the opening (see FIG. 3) on the upper surface of the cylinder acts on the upper surface of the upper piston. It is configured. The spring 75 is disposed below the lower piston 73 and is set to be pushed up from below the piston 73 with a predetermined force. The communication passage 76 communicates the arrangement portion of the spring 75 in the cylinder 71 with the suction passage 46 a of the low-stage compression element 40.

  With this configuration, the pistons 72 and 73 are subjected to the elastic force of the spring 75 and the low pressure pressure resulting from the suction refrigerant on the low-stage compression element side 40 from below, and from above the sealed container It is comprised so that the intermediate pressure by the gas refrigerant in 2 may act. The spring 75 pushes up the pistons 72 and 73 to a predetermined upper position when the intermediate pressure drops to a predetermined pressure, and pushes the pistons 72 and 73 downward to a predetermined position when the intermediate pressure rises beyond the predetermined pressure. The elastic force is set.

  As shown in FIGS. 6 and 7, the communication passage 77 communicates the inside of the sealed container 2 and the portion between both pistons 73 and 74 in the cylinder 71 when the pistons 73 and 74 move to a predetermined upper position. When 73 and 74 move to a predetermined lower position, they are formed so as to open to the upper surface position of the upper piston 72 in the cylinder 71.

  6 and 7, when the pistons 73 and 74 are moved to a predetermined upper position, the communication passage 78 has a compression chamber 21a in the cylinder of the high-stage compression element 20 and both pistons 73 in the cylinder 71. The portion between 74 is communicated, and the opening into the cylinder 71 is closed by the side surface of the upper piston 72 when the pistons 73, 74 move downward to a predetermined position.

  For example, it is assumed that the two-stage compression rotary compressor 1 is used in a heat pump type hot water supply apparatus, and the two-stage compression rotary compressor 1 shows a pressure characteristic diagram shown in FIG. In this case, when the outside air temperature is −10 ° C., in the two-stage compression rotary compressor 1, the intermediate pressure is about 5 MPaG, the discharge pressure is about 12 MPaG, and the low pressure is 2 MPaG, and the pistons 72 and 73 are in the upper predetermined positions. The elastic force of the spring 75 is set so as to move and perform a power saving operation.

  Further, the opening position of the communication passage 78 to the compression chamber 21a is set to an appropriate position from the suction port 26 to the discharge port 29 in the compression chamber 21a of the low-stage compression element 40, as shown in FIG. . Note that the position sets the amount of compressed refrigerant in the higher stage compression element at the time of power saving operation described later.

  In the two-stage compression rotary compressor 1, the carbon dioxide (CO 2), which is a natural refrigerant, is used as the refrigerant in consideration of the earth environment and flammability and toxicity. Further, as the lubricating oil, existing ones such as mineral oil (mineral oil), alkylbenzene oil, ether oil, ester oil and the like are used.

The operation of the two-stage compression rotary compressor 1 according to this embodiment configured as described above will be described. First, the basic operation mode will be described.
The stator coil 6b of the electric motor 3 is energized through the terminal 5 and a wiring (not shown). When the stator coil 6b is energized, the electric motor 3 is activated and the rotor 7 is rotated. The upper and lower eccentric parts 22 and 42 of the high stage compression element 20 and the low stage compression element 40 provided integrally with the rotary shaft 4 are rotated by the rotation of the rotor 7 and are fitted to the upper and lower eccentric parts 22 and 42. The upper and lower rollers 23 and 43 eccentrically rotate in the upper and lower cylinders 21 and 41.

Thereby, in the low-stage compression element 40, the refrigerant in the refrigerant circuit connected to the outside passes through the suction pipe 51 and the suction passage 46a formed in the lower support member 45, and further, the lower cylinder in FIG. The air is sucked into the low pressure chamber side of the compression chamber 41a of the lower cylinder 41 via the suction port 46 shown in the bottom view of 41. The low-pressure (LP) refrigerant sucked into the compression chamber 41a is compressed by the operation of the lower roller 43 and the lower vane 44 to become an intermediate pressure (MP), from the high-pressure chamber side of the lower cylinder 41 to the discharge port 49 and the lower support member 45. It is discharged into the formed discharge silencer chamber 47.
The intermediate-pressure gas refrigerant discharged to the discharge silencer chamber 47 is discharged from the intermediate discharge pipe 66 into the sealed container 2 through a communication path (not shown). Thereby, the inside of the sealed container 2 becomes an intermediate pressure.

  The intermediate-pressure gas refrigerant in the hermetic container 2 is sucked into the high-stage compression element 20 through the suction pipe 31, and the second-stage compression action is performed. That is, the intermediate-pressure gas refrigerant passes through the suction passage 26a formed in the upper support member 25 and passes through the suction port 26 shown in the top view of the upper cylinder 21 in FIG. 5 to the low pressure chamber side in the compression chamber 21a of the upper cylinder 21. Inhaled. The suctioned intermediate-pressure gas refrigerant is compressed in the second stage by the operation of the upper roller 23 and the upper vane 24 to become a high-temperature high-pressure (HP) gas refrigerant, and is discharged from the high-pressure chamber side through the discharge port 29. Is done. The refrigerant discharged from the high-stage compression element 20 passes through a refrigerant circuit (not shown) provided outside the two-stage compression rotary compressor 1 through a discharge pipe 32 from a discharge silencer chamber 27 formed in the upper support member 25. It circulates and is again sucked into the lower stage compression element 40 side.

The two-stage compression rotary compressor 1 according to the present embodiment is used in a heat pump type hot water supply device, and has the operating characteristics illustrated in FIG. 8 during hot water supply operation, the outside air temperature exceeds −10 ° C. If it is, the operation is performed in the above basic operation mode. 8, when the outside air temperature is −10 ° C. or higher, the high pressure side pressure HP is 12 MPaG or higher, the intermediate pressure MP is 5 MPaG or higher, and the low pressure side pressure LP is 4 MPaG or higher. The difference is 7 MPaG or less. Therefore, in the two-stage compression rotary compressor 1, when the intermediate pressure is equal to or higher than a predetermined value (in this case, 5 MPaG), the intermediate pressure (MP) in the sealed container 2 acting on the pistons 72 and 73 downward from above is reduced. It is set to be larger than the resultant force of the elastic force of the spring 75 acting on the pistons 72 and 73 from the lower side to the upper side and the low pressure side pressure guided from the communication path 76.
By setting in this way, the two-stage compression rotary compressor 1 has the pistons 72 and 73 positioned at predetermined positions when the outside air temperature is −10 ° C. or higher (that is, the intermediate pressure is 5 MPaG or higher). As a result, the communication passage 78 is closed. Therefore, in this state, the inside of the sealed container 2 and the inside of the compression chamber 21a of the high-stage compression element 20 are not directly communicated with each other via the communication passage 77 and the communication passage 78, and the operation of the above basic mode is performed. Is called.

  However, when the outside air temperature is −10 ° C. or lower (that is, the intermediate pressure is 5 MPaG or lower), the resultant force acting on the lower surface of the piston 73 becomes larger than the intermediate pressure of the sealed container 2 acting on the upper surface of the piston 72, 72 and 73 move upward to a predetermined position. As a result, the inside of the sealed container 2 and the compression chamber 21a of the high-stage compression element 20 are directly communicated with each other via the communication path 77, the cylinder 71, and the communication path 78.

  Therefore, in the high-stage compression element 20, the contact point rotates until the contact point between the upper roller 23 and the cylinder 21 exceeds the opening 78 a (see FIG. 5) of the communication path 78 even if it exceeds the suction port 26. The compression action is not performed on the front side. This means that the cylinder volume is substantially reduced. Therefore, the intake air amount in the high stage side compression element 20 decreases, and the intermediate pressure moves to the solid line above the conventional dotted line in FIG. Thereby, the high-low pressure difference in the high stage side compression element 20 can be reduced from the conventional characteristic. This is called power saving operation.

  In the two-stage compression rotary compressor according to the present embodiment, as described above, the pressure control valve 70 for performing the power saving operation is housed in the housing constituting the rotary compression mechanism section 10, so In the refrigeration apparatus using the compression rotary compressor 1, a bypass circuit, an electromagnetic on-off valve, and a pressure detection device are not required for the refrigerant circuit Note as in the conventional case, and the device is simplified.

The pressure control valve 70 opposes the resultant force of the spring 75 and the low pressure side pressure to the gas refrigerant pressure in the sealed container 2 with respect to the pistons 72 and 73 slidably housed in the cylinder 71. When the discharge pressure of the low-stage compression element 40 drops below a predetermined value, the pistons 72 and 73 are moved in one direction within the cylinder 71 (in this case, the upper predetermined position in this case) against the intermediate pressure. ), The gas refrigerant in the hermetic container 2 can be introduced into the cylinder 21 of the high-stage compression element 20, and the resultant force is increased when the discharge pressure of the low-stage compression element 40 rises above a predetermined value. Against this, the piston 72, 73 is moved to the other direction side (in this case, a predetermined position downward) by the gas refrigerant in the sealed container 2 to block the introduction of the gas refrigerant in the sealed container 2 into the cylinder 21. Configured as Because there, as the drive mechanism is only the spring 75 is used, it is possible to simplify the structure of the pressure regulating means.
In the present embodiment, since the electric motor 3 is configured to be capable of controlling the rotational speed, the ability of the two-stage compression rotary compressor 1 can be controlled by controlling the rotational speed of the electric motor 3. Further, when the compression capacity is controlled by controlling the number of revolutions of the electric motor 3 in this way, the intermediate pressure also changes. In such a case, the above-described pressure control valve 70 is operated and the intermediate pressure can be adjusted. .

  Therefore, when the two-stage compression type rotary compressor 1 of the present embodiment is used for a car cooler or a heat pump type hot water supply device, it is possible to operate safely under a wide range of outside air temperatures.

1 is a longitudinal sectional view of a two-stage compression rotary compressor according to an embodiment of the present invention. It is a bottom view of the lower support member of the same two-stage compression rotary compressor. It is a top view of the upper support member and upper cover of the same two-stage compression rotary compressor. It is a bottom view of the lower cylinder of the same two-stage compression rotary compressor. It is a top view of the upper cylinder of the same two-stage compression rotary compressor. It is a schematic structure diagram of a pressure control valve in the same two-stage compression rotary compressor, and shows a state when the intermediate pressure is lower than a predetermined value. It is a schematic structure diagram of a pressure control valve in the same two-stage compression rotary compressor, and shows a state when the intermediate pressure exceeds a predetermined value. It is explanatory drawing of the intermediate pressure control by the pressure control valve of the 2 stage | paragraph compression type rotary compressor. It is a general characteristic diagram which shows the relationship between external temperature and high pressure, low pressure, and intermediate pressure at the time of applying a two-stage compression type rotary compressor to a heat pump type hot water supply apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Two-stage compression type rotary compressor 2 Sealed container 3 Electric motor 10 Rotary compression mechanism part 20 High stage side compression element 21 Upper cylinder 21a Compression chamber 40 Low stage side compression element 46 Suction port 46a Suction passage 70 Pressure control valve 71 Cylinder 73 Upper piston 73 Lower piston 74 Rod 75 Spring 76 Communication path 77 Communication path 78 Communication path 78a Opening

Claims (4)

A rotary compression mechanism unit that includes a low-stage compression element and a high-stage compression element, and that discharges gas discharged from the low-stage compression element to the high-stage compression element, and drives the rotary compression mechanism unit An electric motor, a hermetic container that houses the electric motor and the rotary compression mechanism, and is filled with a discharge gas refrigerant of a low-stage compression element, and a pressure control valve that is housed in a housing constituting the rotary compression mechanism This pressure control valve introduces the gas refrigerant in the hermetic container into the cylinder of the high-stage compression element when the discharge pressure of the low-stage compression element drops below a predetermined value, and compresses the low-stage compression A two-stage compression rotary compressor characterized by being configured to block introduction of gas refrigerant in the sealed container into the cylinder when the discharge pressure of the element rises above a predetermined value. The pressure control valve includes a piston and a cylinder that slidably accommodates the piston, and the piston is configured to oppose a low pressure side pressure and a resultant force of the elastic force of the spring and a gas refrigerant pressure in the sealed container. When the discharge pressure of the low-stage compression element is reduced to a predetermined value or less, the piston is moved in one direction in the cylinder by the resultant force, and the gas refrigerant in the sealed container is moved into the cylinder of the high-stage compression element. When the discharge pressure of the low-stage compression element rises above a predetermined value, the piston is moved in the other direction by the gas refrigerant pressure in the sealed container against the resultant force, and the sealed container 2. The two-stage compression rotary compressor according to claim 1, wherein the two-stage compression rotary compressor is configured to block introduction of the gas refrigerant into the cylinder. A car air conditioner comprising the two-stage compression rotary compressor according to claim 1 or 2 and using carbon dioxide as a refrigerant. A heat pump type hot water supply apparatus using the two-stage compression type rotary compressor according to claim 1 or 2 and using carbon dioxide as a refrigerant.

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