JP5863326B2 - 2-stage compressor - Google Patents

Description

  The present invention relates to a two-stage compressor in which a first compression mechanism and a second compression mechanism are provided in a sealed housing.

  Two compression mechanisms, that is, a low-stage compression mechanism (rotary compressor) and a high-stage compression mechanism (scroll compression mechanism) are provided in the hermetic housing to seal the intermediate pressure gas compressed by the low-stage rotary compression mechanism. A two-stage compressor that discharges into the housing and compresses the intermediate pressure gas to a high pressure by a high-stage scroll compression mechanism is disclosed in, for example, Patent Document 1. In such a two-stage compressor, in order to cope with a wider range of operating conditions, it is required to employ a capacity control mechanism.

  Various compressor capacity control mechanisms have been proposed. Among them, as a capability control mechanism of a rotary compressor, for example, as shown in Patent Document 2-4, a vane partitioning a compression chamber can be moved between a full load position and an unload position via a switching mechanism. A capability control mechanism that enables control of the compression capability by making it possible is known.

JP 2008-175340 A JP 2004-44571 A Japanese Patent No. 4220514 Japanese Patent No. 4504668

  By applying the capability control mechanism shown in Patent Literature 2-4 to the low-stage rotary compression mechanism of the two-stage compressor shown in Patent Literature 1, a two-stage with a capability control mechanism is provided. A compressor can be comprised and it becomes possible to respond to a wide range of operating conditions. However, in the ones disclosed in Patent Documents 2 and 3, in order to move the vane to the unloading position reliably during unloading control, the vane and the unloading piston are connected together, and at the tip end side of the vane. A mechanism (Patent Document 2) for applying pressure in the hermetic housing or a spring for removing vanes (Patent Document 3) is provided.

  As a result, the configuration of the vane is complicated, and the weight is increased by integration with the piston, and the inertial force during the reciprocating motion is increased, which causes problems such as vane jumping and collision noise easily occurring. was there. On the other hand, what is shown in Patent Document 4 is to move the vane to the unload position by using the magnetic force of the magnet. In such a configuration, naturally, the vane must be made of a magnetic material. Therefore, there is a problem that freedom of material selection is lost and it becomes difficult to employ vanes made of carbon or resin.

  The present invention has been made in view of such circumstances. The vane can be reliably detached from the rotor surface without being connected to the unloading piston, and the configuration of the vane itself can be simplified. An object of the present invention is to provide a two-stage compressor capable of ensuring the degree of freedom of material selection.

In order to solve the above problems, the two-stage compressor of the present invention employs the following means.
That is, in the two-stage compressor according to the present invention, the first compression mechanism and the second compression mechanism are provided in the sealed housing, and the intermediate pressure gas compressed by the first compression mechanism is discharged into the sealed housing. In the two-stage compressor that compresses the intermediate pressure gas to a high pressure by the second compression mechanism, the first compression mechanism is a rotary compression mechanism, and the rotary compression mechanism fills the vane that partitions the compression chamber. A capacity control mechanism that controls the compression capacity by moving to a load position and an unload position is provided. During unload control by the capacity control mechanism, the inside of the hermetic housing is switched to a low pressure and is loaded on the rear end face of the vane. It is characterized in that pressure switching means for switching the pressure being applied to low pressure is provided.

According to the present invention, the first compression mechanism of the two-stage compressor is a rotary compression mechanism, and the rotary compression mechanism moves the vane that partitions the compression chamber to the full load position and the unload position to compress the compression capacity. The pressure control means is provided for switching the pressure inside the sealed housing to a low pressure and switching the pressure applied to the rear end face of the vane to a low pressure during unload control by the capability control mechanism. When the capacity control mechanism is activated to control the unloading of the compression capacity, the pressure in the sealed housing is switched to low pressure via the pressure switching means, and the pressure in the sealed housing loaded on the rear end face of the vane is set to the intermediate pressure. By switching from low to low pressure, when the vane is moved from the full load position to the unload position by the capacity control mechanism, the vane is surely detached from the rotor surface. They can be moved in the unload position. Therefore, while ensuring the responsiveness of the capacity control mechanism and improving its reliability, in adopting the capacity control mechanism, without changing the configuration of the vane itself, while ensuring the freedom of design, Simplification of the configuration, optimization of materials, and the like can be achieved.

  Furthermore, the two-stage compressor according to the present invention is characterized in that, in the above-described two-stage compressor, the pressure switching means can be switched before the capacity control mechanism is activated during unload control. To do.

  According to the present invention, since the pressure switching means can be switched before the capacity control mechanism is activated during the unload control, the pressure in the sealed housing is switched from the intermediate pressure to the low pressure during the unload control. After that, the capacity control mechanism can be activated. Therefore, when the capacity control mechanism is activated, the pressure already applied to the rear end face of the vane is switched from the intermediate pressure to the low pressure, so that the vane is surely detached from the rotor surface and unloaded smoothly and reliably. It can be switched to the state.

  Furthermore, in the two-stage compressor according to the present invention, in any one of the above-described two-stage compressors, the capacity control mechanism includes a cylinder in which the pressure applied to one end side can be switched to either high pressure or low pressure. , Slidably accommodated in the cylinder, coupled to a fixed end side of a vane pressing spring that presses the vane toward the rotor, and is movable between a full load position and an unload position by switching between the high pressure and the low pressure. And a vane detachment means that moves the piston to an unload position during unload control so that the vane can be detached from the rotor surface.

  According to the present invention, the capacity control mechanism includes a cylinder in which the pressure applied to the one end side can be switched to either high pressure or low pressure, and is slidably accommodated in the cylinder, and the vane is disposed in the rotor. The piston is connected to the fixed end side of the vane pressing spring that presses to the side, and can be moved to the full load position and the unload position by switching between high pressure and low pressure, and during unload control, the piston is moved to the unload position. Since the vane detachment means that enables the vane to be detached from the rotor surface is provided, the pressure in the hermetic housing is switched from the intermediate pressure to the low pressure by the pressure switching means during unload control, and the rear end face of the vane is loaded. Is switched to low pressure, and is introduced to one end of the cylinder. The high pressure applied to the piston is switched to low pressure, and the piston is vaned. By moving to the unloading position via the vane detachment means with pressure spring, to release the pressing force is loaded on the rear end surface of the vane can be disengaged vane from the rotor surface. Therefore, even if the vane and the piston are not connected, the vane can be reliably detached from the rotor surface and switched to the unloaded state.

  Furthermore, the two-stage compressor according to the present invention is characterized in that, in the above-described two-stage compressor, the vane disengaging means is configured by a spring that urges the piston toward the unload position.

  According to the present invention, since the vane detachment means is constituted by the spring that urges the piston toward the unload position, the piston is switched by switching the pressure applied to one end side of the cylinder from high pressure to low pressure. The piston is quickly moved to the unload position via the force of the spring urging the unload position side, releasing the pressing force applied to the rear end surface of the vane and removing the vane from the rotor surface. Can be withdrawn. Therefore, the vane can be reliably detached from the rotor surface by using a simple spring force, and can be switched smoothly and reliably to the unload state.

  Furthermore, in the two-stage compressor according to the present invention, in any one of the above-described two-stage compressors, the spring for the vane releasing means is disposed in the cylinder and is concentrically arranged around the piston with the vane pressing spring. It is provided.

  According to the present invention, since the spring for the vane detaching means is disposed in the cylinder and concentrically with the vane pressing spring around the piston, the spring for the vane detaching means accommodates the piston. It can be accommodated and installed compactly in the cylinder. Therefore, the capacity control mechanism can be reduced in size and size regardless of the addition of the vane detaching means, and the downsizing and downsizing of the two-stage compressor can be maintained, and the mountability can be ensured.

  Further, in the two-stage compressor according to the present invention, in any one of the two-stage compressors described above, the vane side end portion of the vane pressing spring is in contact with the rear end portion of the vane. It is characterized by.

  According to the present invention, since the vane side end portion of the vane pressing spring is in contact with the rear end portion of the vane, the vane itself is separated from the piston, the vane pressing spring, and the like. Can do. Therefore, the vane jump, the generation of a collision sound, and the like can be suppressed by performing an optimal design for the vane while avoiding problems such as an increase in weight and material restrictions.

  Furthermore, the two-stage compressor according to the present invention is characterized in that in any one of the two-stage compressors described above, the piston is made of a fluorine-based resin material.

  According to the present invention, since the piston is made of a fluorine-based resin material, the piston can be reduced in weight, and slidability and wear resistance when moving between the full load position and the unload position can be achieved. Etc. can be secured. Therefore, it is possible to improve the quality and reliability of the capacity control mechanism and reduce the collision noise.

  Furthermore, the two-stage compressor of the present invention is the above-described two-stage compressor, wherein the pressure switching means is a bypass pipe with an electromagnetic valve that connects between the hermetic housing and a gas suction pipe to the compressor. It is characterized by comprising.

  According to the present invention, since the pressure switching means is constituted by the bypass pipe with a solenoid valve that connects between the hermetic housing and the gas suction pipe to the compressor, the pressure in the hermetic housing is intermediate during unload control. When switching from pressure to low pressure, it is only necessary to open the solenoid valve of the bypass pipe, and the pressure in the sealed housing can be easily switched. Therefore, a simple and highly reliable capability control mechanism can be configured.

  Furthermore, in the two-stage compressor according to the present invention, in any one of the above-described two-stage compressors, the rotary compression mechanism is a two-cylinder rotary compression mechanism, and at least one of the cylinders is provided with the capacity control mechanism. It is characterized by.

  According to the present invention, since the rotary compression mechanism is a two-cylinder rotary compression mechanism, and at least one of the cylinders is equipped with a capacity control mechanism, the rotary compression mechanism is a two-cylinder rotary compression mechanism. The capacity of the two-stage compressor can be easily increased, and at the same time, by providing at least one of the cylinders with a capacity control mechanism, the operable range can be further expanded. Therefore, it is possible to provide a two-stage compressor that can cope with a wider range of operating conditions.

According to the present invention, when the capacity control mechanism is operated to control the unloading of the compression capacity, the pressure in the sealed housing is switched to the low pressure via the pressure switching means, and the pressure in the sealed housing loaded on the rear end face of the vane is changed. By switching the pressure from the intermediate pressure to the low pressure, when the vane is moved from the full load position to the unload position by the capacity control mechanism, the vane can be surely detached from the rotor surface and moved to the unload position. In addition to ensuring the responsiveness of the capacity control mechanism and increasing its reliability, in adopting the capacity control mechanism, without changing the configuration of the vane itself, while ensuring the freedom of design, Simplification of the configuration, optimization of materials, and the like can be achieved.

It is the external view which fractured | ruptured a part of 2 stage compressor which concerns on 1st Embodiment of this invention. It is an AA cross-section equivalent view which shows the state at the time of the full load of the rotary compression mechanism of the two-stage compressor of FIG. FIG. 3 is a cross-sectional view corresponding to BB in FIG. 2. It is an AA cross-section equivalent view which shows the state at the time of unloading of the rotary compression mechanism of the two-stage compressor of FIG. FIG. 5 is a cross-sectional view corresponding to CC line in FIG. 4.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 shows an external view in which a part of the two-stage compressor according to the first embodiment of the present invention is broken, FIG. 2 shows an AA cross-sectional view, and FIG. FIG. 2 is a cross-sectional view corresponding to the line BB in FIG. In the present embodiment, for convenience, the first compression mechanism 2 and the second compression mechanism 3 are provided in the hermetic housing, and the first compression mechanism 2 is a rotary compression mechanism and the second compression mechanism 3. Although the two-stage compressor is described as a scroll compression mechanism, the second compression mechanism 3 is not limited to the scroll compression mechanism, and other types of compression mechanisms may be used.

  The two-stage compressor 1 of this embodiment includes a hermetically sealed housing 10. An electric motor 4 is fixedly installed at a substantially central portion in the hermetic housing 10, and a crankshaft 5 is integrally coupled to the rotor. A rotary compression mechanism 2 as a first compression mechanism is provided at a position below the electric motor 4 on one end side of the crankshaft 5. The rotary compression mechanism 2 functions as a low-stage compression mechanism.

  The low-stage rotary compression mechanism 2 includes a compression chamber 20. The cylinder body 21 is fixedly installed in a sealed housing 10 at a plurality of locations by plug welding or the like, and is fixedly installed above and below the cylinder body 21. An upper bearing 22 and a lower bearing 23 that seal the upper and lower portions, a rotor 24 that is fitted to the crank portion 5A of the crankshaft 5 and rotates around the inner periphery of the compression chamber 20, and a radius provided in the cylinder body 21 A vane 26 that is slidably fitted in a vane groove 25 in a direction and divides the compression chamber 20 into a suction side and a discharge side, and a vane pressing spring 27 that presses the vane 26 toward the rotor 24. ing.

  The rotary compression mechanism 2 itself may be a known one, and sucks low-pressure refrigerant gas (working gas) into the compression chamber 20 through the suction pipe 28, and the refrigerant gas reaches the intermediate pressure by the rotation of the rotor 24. After the compression, the liquid is discharged into the discharge chamber 29 and discharged from the discharge chamber 29 into the sealed housing 10. The intermediate-pressure refrigerant gas flows through or around the electric motor 4 and flows into the space above the electric motor 4, and is sucked into the scroll compression mechanism, which is the second compression mechanism 3, and is compressed in two stages. It has become.

  The scroll compression mechanism, which is the second compression mechanism 3, is provided on the other end side of the crankshaft 5 and at a position above the electric motor 4, and is incorporated on a support member (not shown) that supports the crankshaft 7. It is like that. The scroll compression mechanism 3 functions as a high-stage side compression mechanism. After the intermediate pressure refrigerant gas is sucked into the compression chamber 32 formed by the pair of fixed scrolls 30 and the orbiting scroll 31 and compressed to a high pressure state, The discharge port 33 provided in the fixed scroll 30 is discharged into the discharge chamber 34 and discharged to the outside, that is, to the refrigeration cycle side through the discharge pipe 35. The scroll compression mechanism 3 itself may be a known one.

In the above-described two-stage compressor, a capacity control mechanism 40 configured as follows is incorporated in the low-stage rotary compression mechanism 2.
As shown in FIGS. 2 and 3, the capacity control mechanism 40 is coupled to the outer peripheral end side of the vane groove 25 in which the vane 26 and the vane pressing spring 27 provided in the cylinder body 21 are incorporated. A cylindrical cylinder 41 projecting from the hermetic housing 10 to the outside, and a fixed end side of a vane pressing spring 27 that is slidably accommodated in the cylinder 41 and presses the vane 26 toward the rotor 24 And a piston 42 movable between a full load position and an unload position by switching between high and low pressure, and during unload control, the piston 42 is moved to the unload position, and the vane 26 is moved from the surface of the rotor 24. A spring (coil spring) 43 is provided as vane detachment means that can be detached.

  The cylinder 41 is formed by integrating a cylinder (A) 41A and a cylinder (B) 41B, each of which is open on one end side, by fastening each other with a screw 44, and a piston 42 is slidably accommodated therein. It is. The piston 42 is made of a fluorine-based resin material such as tetrafluoroethylene (PTFE) in order to ensure weight reduction, slidability, and wear resistance. On the inner end side of the piston 42, the fixed end side of the vane pressing spring 27 is locked and integrally coupled. Further, the spring (vane detaching means) 43 partially reduces the diameter of the outer peripheral portion on the inner end side of the piston 42, and presses the vane around the piston 42 between the reduced diameter portion and the inner end side of the cylinder 41. It is disposed concentrically with the spring 27 and biases the piston 42 toward the outer end side of the cylinder 41, that is, toward the unload position.

  In addition, a pressure introduction pipe 45 for switching and introducing the control pressure applied to the outer end side of the piston 42 to either a high pressure or a low pressure is provided at an outer end portion of the cylinder 41 protruding outside the sealed housing 10. It is connected. The pressure introduction pipe 45 is provided with a three-way valve 46 as a control pressure switching means, and is sucked into the high-pressure pipe 47 and the two-stage compressor 1 connected in the middle of the discharge pipe 35 from the two-stage compressor 1. A low-pressure pipe 48 connected in the middle of the pipe 28 is connected. A suction accumulator 11 having a relatively small capacity is provided in the suction pipe 28 to the two-stage compressor 1 (in FIG. 1, the connecting portion to the second-stage compressor 1 is omitted). The bracket 12 is integrally assembled with the hermetic housing 10 of the two-stage compressor 1. The low pressure pipe 48 is connected to the upstream side of the suction accumulator 11.

  Further, during normal operation (full load operation), the capacity control mechanism 40 unloads between the inside of the sealed housing 10 of the two-stage compressor 1, which is set to an intermediate pressure, and the suction pipe 28 upstream of the suction accumulator 11. During load control, a pressure switching means for switching the pressure in the sealed housing 10 from an intermediate pressure to a low pressure, that is, a bypass pipe (pressure switching means) 50 with an electromagnetic valve 49 is connected. The electromagnetic valve 49 (pressure switching means) in the bypass pipe 50 is opened prior to switching of the control pressure from high pressure to low pressure by the three-way valve 46 during unload control, and the inside of the sealed housing 10 is changed from intermediate pressure to low pressure. It is configured to be switched.

With the configuration described above, according to the present embodiment, the following operational effects can be obtained.
The low-pressure refrigerant gas sucked into the compression chamber 20 of the rotary compression mechanism 2 on the lower stage side than the suction accumulator 11 through the suction pipe 28 is compressed to the intermediate pressure by the rotation of the rotor 24 and then is discharged to the discharge chamber 28. Exhaled. The intermediate-pressure refrigerant gas is discharged from the discharge chamber 28 into the lower space of the electric motor 4 in the sealed housing 10, and then flows through and around the electric motor 4 to flow into the upper space of the electric motor 4. .

  The intermediate pressure refrigerant gas that has flowed into the upper space of the electric motor 4 is sucked into the compression chamber 32 of the scroll compression mechanism 3 on the higher stage side, and is compressed into two stages at a high pressure by the revolving orbiting motion of the orbiting scroll 31 around the fixed scroll 31. Then, the liquid is discharged into the discharge chamber 34 through the discharge port 33. The high-pressure refrigerant gas is sent out to the outside of the two-stage compressor 1, that is, to the refrigeration cycle side through the discharge pipe 35.

  As described above, during the full load operation in which the refrigerant gas is compressed in two stages by the rotary compression mechanism 2 and the scroll compression mechanism 3, the inside of the sealed housing 10 is set to an intermediate pressure, and the capacity control mechanism 40 is shown in FIGS. Thus, the full load state is set. That is, the electromagnetic valve (pressure switching means) 48 in the bypass pipe 50 is closed, and the three-way valve (control pressure switching means) 46 connects the high pressure pipe 47 and the pressure introduction pipe 45, and the outer end of the cylinder 41 By introducing the high pressure from the discharge pipe 35 to the side, the piston 42 is moved and pressed to the full load position, that is, the inner end side of the cylinder 41. As a result, the tip of the vane 26 is pressed against the surface (outer peripheral surface) of the rotor 24 via the vane pressing spring 27 to partition the inside of the compression chamber 20 into the suction side and the discharge side, and the rotary compression mechanism 2 is loaded. To maintain.

  On the other hand, when the operation is low, unload control is entered to reduce the capacity of the two-stage compressor 1. At this time, first, the solenoid valve (pressure switching means) 49 in the bypass pipe 50 is opened and the inside of the sealed housing 10 is communicated with the suction pipe 28, so that the pressure in the sealed housing 10 is switched from the intermediate pressure to the low pressure. . Thereby, the inside of the vane groove 25 communicating with the inside of the hermetic housing 10 is also set to a low pressure, and the intermediate pressure applied to the rear end face side of the vane 26 is also switched to a low pressure. Thereafter, the three-way valve (control pressure switching means) 46 is switched, and the pressure introduction pipe 45 is connected to the low pressure pipe 48 connected to the suction pipe 28.

  For this reason, the high pressure loaded on the rear end side of the cylinder 41 is switched to the low pressure, and the pressing force due to the high pressure of the piston 42 is released. Therefore, as shown in FIGS. The vane pressing spring 27 is moved to the rear end side of the cylinder 41, that is, to the unload position. As a result, the pressure applied by the vane pressing spring 27 applied to the rear end surface of the vane 26 and the pressure (intermediate pressure) in the hermetic housing 10 are released, so that the vane 26 has a pressure difference from the compression chamber 20. Therefore, the gap G is moved radially outward in the vane groove 25, and a gap G is formed between the rotor 24 and the surface of the rotor 24 as shown in FIGS.

  As a result, the low-stage rotary compression mechanism 2 is in an unloaded state and is idled without performing a compression action. The refrigerant discharged into the sealed housing 10 without being compressed by the rotary compression mechanism 2 is directly sucked into the scroll compression mechanism 3 and compressed to a pressure corresponding to the compression ratio on the scroll compression mechanism 3 side, whereby a refrigeration cycle. Discharged to the side. Therefore, the capacity of the two-stage compressor 1 is reduced according to the load.

However, according to the present embodiment, when the capacity control mechanism 40 is operated to control the unloading of the compression capacity, the pressure in the sealed housing 10 is switched to a low pressure by the electromagnetic valve (pressure switching means) 49, and Since the pressure in the sealed housing 10 loaded on the end face is switched from the intermediate pressure to the low pressure, when the vane 26 is moved from the full load position to the unload position by the capacity control mechanism 40, the vane 26 Can be reliably detached from the surface of the rotor 24 and moved to the unload position.

  Therefore, the responsiveness of the capacity control mechanism 40 can be ensured and the reliability thereof can be improved, and the degree of freedom of design can be increased without changing the configuration of the vane 26 itself when the capacity control mechanism 40 is adopted. It is possible to simplify the structure or optimize the material while securing the above.

  The electromagnetic valve 49, which is a pressure switching means, is switched before the capacity control mechanism 40 is activated during unload control. For this reason, at the time of unload control, the capacity control mechanism 40 can be operated after the pressure in the sealed housing 10 is switched from the intermediate pressure to the low pressure. Therefore, when the capacity control mechanism 40 is operated, the pressure already applied to the rear end face of the vane 26 is switched from the intermediate pressure to the low pressure. Therefore, the vane 26 is surely detached from the surface of the rotor 24 and smooth. And it can switch to an unload state reliably.

  Further, the capacity control mechanism 40 includes a cylinder 41 in which the pressure applied to one end can be switched to either high pressure or low pressure, and is slidably accommodated in the cylinder 41, and the vane 26 is disposed in the rotor 24. A piston 42 that is coupled to a fixed end side of a vane pressing spring 27 that presses to the side and is movable between a full load position and an unload position by switching between high pressure and low pressure, and during unload control, the piston 42 is brought to an unload position. It is configured to include a spring (vane detaching means) 43 that is moved so that the vane 26 can be detached from the surface of the rotor 24.

  For this reason, at the time of unload control, the pressure in the sealed housing 10 is switched from the intermediate pressure to the low pressure by the electromagnetic valve (pressure switching means) 49, the pressure loaded on the rear end face of the vane 26 is switched to the low pressure, and the cylinder 41 The piston 42 is loaded on the rear end face of the vane 26 by switching the high pressure applied to the piston 42 to the low pressure and moving the piston 42 to the unloading position together with the vane pressing spring 27 via the spring 43. The pressing force applied can be released, and the vane 26 can be separated from the surface of the rotor 24. Therefore, even if the vane 26 and the piston 42 are not connected, the vane 26 can be reliably detached from the surface of the rotor 24 and switched to the unloaded state.

  Further, according to the present embodiment, the means for detaching the vane 26 from the surface of the rotor 24 includes the spring 43 that biases the piston 42 toward the unload position. For this reason, when the pressure applied to one end side of the cylinder 41 is switched from high pressure to low pressure, the piston 42 is quickly unloaded through the force of the spring 43 that biases the piston 42 toward the unload position. The vane 26 can be released from the surface of the rotor 24 by moving to the load position and releasing the pressing force applied to the rear end face of the vane 26. Therefore, the vane 26 can be reliably detached from the rotor surface by using a simple spring force, and can be smoothly and reliably switched to the unloaded state.

  Furthermore, the vane side end portion of the vane pressing spring 27 is in contact with the rear end portion of the vane 26. For this reason, it can be set as the single-piece | unit structure which cut | disconnected vane 26 itself from piston 42, the vane press spring 27, etc. FIG. Therefore, by performing an optimal design for the vane 26 while avoiding problems such as an increase in weight and material constraints, it is possible to suppress the occurrence of vane jumps and collision noise.

  The piston 42 is made of a fluorine resin material such as tetrafluoroethylene (PTFE). As a result, the weight of the piston 42 can be reduced, and slidability and wear resistance when moving between the full load position and the unload position can be ensured. It is possible to improve quality and reliability and reduce collision noise.

  In addition, the means for switching the pressure in the hermetic housing 10 is constituted by a bypass pipe 50 with an electromagnetic valve 49 that connects between the hermetic housing 10 and the gas suction pipe 28 to the two-stage compressor 1. When the pressure in the sealed housing 10 is switched from the intermediate pressure to the low pressure during the unload control, it is only necessary to open the electromagnetic valve 49 in the bypass pipe 50, and the pressure in the sealed housing 10 can be easily switched. A simple and highly reliable capability control mechanism 40 can be configured.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
The present embodiment differs from the first embodiment described above in that the low-stage rotary compression mechanism 2 is a two-cylinder rotary compression mechanism. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, the two-cylinder rotary compression mechanism can be configured by arranging the rotary compression mechanism 2 described in the first embodiment in two upper and lower stages.

  In other words, the crank portion 5A provided at the lower end portion of the crankshaft 5 is disposed opposite to the upper and lower portions at, for example, a 180 ° phase shift, and the same as the rotary compression mechanism 2 described above with respect to each crank portion 5A. What is necessary is just to install the rotary compression mechanism of a structure with a partition plate etc. interposed between them. In this case, of course, the cylinder body 21, the upper bearing 22, the lower bearing 23, etc. may be shared. Then, the same capacity control mechanism 40 as that of the first embodiment may be incorporated into one or both cylinders of the two-cylinder rotary compression mechanism.

  As described above, the low-stage rotary compression mechanism 2 is a two-cylinder rotary compression mechanism, and at least one of the cylinders is provided with the capacity control mechanism 40, thereby simplifying the capacity of the two-stage compressor 1. The capacity can be increased. At the same time, by providing one or both of the cylinders with the capacity control mechanism 40, multistage capacity control is possible, so that the operable range can be further expanded. Therefore, the two-stage compressor 1 that can cope with a wider range of operating conditions can be provided.

In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, in the above-described embodiment, the embodiment in which the capacity control mechanism 40 is provided to protrude outside the sealed housing 10 has been described. However, the capacity control mechanism 40 may be provided inside the sealed housing 10. .
Further, although the control pressure switching means for switching the pressure applied to one end of the cylinder 41 of the capacity control mechanism 40 to either high pressure or low pressure is the three-way valve 46, it may be replaced by two electromagnetic valves.

  Furthermore, although the said embodiment demonstrated the example which made the front-end | tip of the vane press spring 27 which presses the vane 26 contact | abutted with respect to the rear-end part of the vane 26, this invention is not limited to these. The vane pressing spring 27 can be applied to the rear end portion of the vane 26. In this case, the vane 26 can be removed from the surface of the rotor 24 with the same effect. Can be obtained.

1 Two-stage compressor 2 Rotary compression mechanism (first compression mechanism)
3 Scroll compression mechanism (second compression mechanism)
10 Sealed housing 20 Compression chamber 24 Rotor 26 Vane 27 Vane pressing spring 40 Capacity control mechanism 41 Cylinder 42 Piston 43 Spring (vane release means)
49 Solenoid valve (pressure switching means)
50 Bypass piping (pressure switching means)

Claims (9)

A first compression mechanism and a second compression mechanism are provided in the hermetic housing, the intermediate pressure gas compressed by the first compression mechanism is discharged into the hermetic housing, and the intermediate pressure gas is increased in pressure by the second compression mechanism. In a two-stage compressor that compresses into two stages,
The first compression mechanism is a rotary compression mechanism;
The rotary compression mechanism includes a capacity control mechanism that controls a compression capacity by moving a vane that defines a compression chamber to a full load position and an unload position,
Two-stage compression, characterized in that, during unload control by the capacity control mechanism , a pressure switching means is provided for switching the inside of the sealed housing to a low pressure and switching the pressure applied to the rear end face of the vane to a low pressure. Machine.   2. The two-stage compressor according to claim 1, wherein the pressure switching means can be switched before the capacity control mechanism is activated during unload control.   The capacity control mechanism includes a cylinder that is switchable between a high pressure and a low pressure applied to one end thereof, and is slidably accommodated in the cylinder and presses the vane toward the rotor. A piston that is coupled to a fixed end side of the vane pressing spring and is movable to a full load position and an unload position by switching between the high pressure and the low pressure, and during unload control, the piston is moved to the unload position, The two-stage compressor according to claim 1, further comprising vane detachment means that makes it possible to detach the vane from the rotor surface.   4. The two-stage compressor according to claim 3, wherein the vane detaching means is configured by a spring that urges the piston toward the unload position.   5. The two-stage compressor according to claim 3, wherein the spring for the vane detaching means is disposed in the cylinder and concentrically with the vane pressing spring around the piston.   The two-stage compressor according to any one of claims 3 to 5, wherein a vane side end portion of the vane pressing spring is in contact with a rear end portion of the vane.   The two-stage compressor according to any one of claims 3 to 6, wherein the piston is made of a fluorine resin material.   8. The pressure switching device according to claim 1, wherein the pressure switching means is constituted by a bypass pipe with a solenoid valve that connects between the hermetic housing and a gas suction pipe to the compressor. Stage compressor. The two-stage compressor according to any one of claims 1 to 8, wherein the rotary compression mechanism is a two-cylinder rotary compression mechanism, and at least one of the cylinders is provided with the capacity control mechanism. .

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