JP4504667B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus that constitutes a refrigeration cycle using a two-cylinder rotary compressor.

  In recent years, a two-cylinder type rotary compressor provided with two sets of upper and lower cylinders constituting a compression mechanism is being standardized. In such a two-cylinder rotary compressor, if a cylinder chamber that always performs a compression action and a cylinder chamber that enables switching between a compression operation and a non-compression operation that is stopped according to the magnitude of the load can be provided. The specifications are expanded and advantageous.

For example, in [Patent Document 1], two cylinder chambers are provided, and if necessary, the vanes of either one of the cylinder chambers are forcibly separated from the rollers, and the cylinder chamber is pressurized and compressed. A two-cylinder rotary compressor characterized in that it is provided with high-pressure introduction means for interrupting is disclosed.
JP-A-1-247786

By the way, in the case of a so-called reciprocating compressor in which the piston accommodated in the cylinder is driven to reciprocate to compress the refrigerant gas, the discharge of the compressed refrigerant gas is intermittent and the pulsation occurs. In particular, in a rotary compressor, refrigerant gas is continuously compressed and discharged, so that no pulsation occurs.
However, in actuality, suction is performed as the roller rotates eccentrically in the cylinder, and the compression and discharge are performed so that the discharge valve is opened. Especially, when the discharge process is finished and switched to the suction process, it is instantaneous. There is a space (blank). As a result, although not as remarkable as in a reciprocating compressor, pulsation also exists in a rotary compressor.

In terms of design, in order to reduce supercharging loss due to pulsation in a rotary compressor, the length of the suction pipe that communicates between the accumulator and each cylinder chamber in each compression mechanism is set appropriately. .
In the case of a simple two-cylinder rotary compressor that always performs compression operation in two cylinder chambers, the length of each suction pipe that communicates the accumulator and each cylinder chamber can be set to the same appropriate dimension. However, since it is necessary to provide a switching mechanism in the suction pipe that communicates with the cylinder chamber on the switching side between the compression operation and the non-compression operation, the suction pipe is always longer than the suction pipe that communicates with the cylinder chamber on the compression operation side. turn into.

Therefore, in the compression mechanism portion provided with the cylinder chamber on the side to be switched between the compression operation and the non-compression operation, a so-called supercharging loss occurs at an operation frequency lower than that of the compression mechanism portion to which the suction pipe of an appropriate length is connected. It is easy to generate | occur | produce and the operating efficiency of a compressor falls near the operating frequency.
FIG. 4A is a characteristic diagram of operating efficiency and volumetric efficiency of a two-cylinder rotary compressor with specific supercharging. That is, at the operating frequency F at which supercharging occurs, the amount of refrigerant sucked into the compressor increases, the volume efficiency increases, and a supercharging effect (increase in refrigeration capacity) can be obtained, while a supercharging loss occurs. This reduces the operating efficiency of the compressor.

Therefore, as shown in FIG. 4B, by changing the setting so that the operation frequency F at which supercharging occurs is larger than the maximum operation frequency Fmax, the volume efficiency and the operation are within the range of the maximum operation frequency Fmax. Both efficiencies increase in the same way and no supercharging loss occurs.
Alternatively, as shown in FIG. 4C, by changing the setting so that the operating frequency F at which the supercharging loss occurs and the maximum operating frequency Fmax coincide with each other, the operating efficiency due to the supercharging loss near the upper limit of the operating frequency. However, the maximum supercharging effect due to the increase in volumetric efficiency can be obtained.

  The present invention has been made based on the above circumstances, and an object of the present invention is to provide a switching mechanism including a two-cylinder rotary compressor that switches between a compression operation and a non-compression operation that is a compression stop depending on the magnitude of the load. To provide a refrigeration cycle apparatus that can suppress the supercharging loss of the compressor and improve the operation efficiency in response to the length of the suction passage becoming longer than the appropriate value. It is what.

Refrigeration cycle apparatus of the present invention to satisfy the above object, 2 cylinder type rotary compressor to the electric motor unit and the first compression mechanism and the second compression mechanism accommodated in the closed case, first, The gas compressed by the compression mechanism part 2 is once discharged into the sealed case to obtain a high pressure in the case.
The suction passage communicates with each compression mechanism portion of the two-cylinder rotary compressor, and introduces low-pressure refrigerant into the cylinder chamber of each compression mechanism portion via the accumulator of the refrigeration cycle .
The first and second compression mechanisms include a cylinder chamber having a cylinder chamber that accommodates the eccentric roller so as to be eccentrically rotatable. The first and second compression mechanisms are pressed and urged so that the tip edge of the cylinder comes into contact with the circumferential surface of the eccentric roller. A vane that bisects the cylinder chamber along the rotation direction and a vane chamber that accommodates the rear side end of the vane.
The suction passage communicating with the cylinder chamber of the second compression mechanism section is provided with switching means for introducing suction pressure or discharge pressure to the cylinder chamber. The vane provided in the cylinder of the first compression mechanism is pressed and urged by a spring member provided in the vane chamber.
The vane provided in the cylinder of the second compression mechanism section is guided to the pressure inside the case and the cylinder chamber when the suction pressure is guided to the cylinder chamber of the second compression mechanism section by the switching means. Due to the pressure difference from the suction pressure, the tip edge of the vane is pressed and urged so as to contact the peripheral surface of the eccentric roller.
When the discharge pressure is guided, the pressure inside the case guided to the vane chamber and the discharge pressure guided to the cylinder chamber are balanced, and the pressure is balanced at the front and rear ends of the vane. Separate from the peripheral surface.
Furthermore, a space volume is provided in the middle of the suction passage that connects the accumulator and the cylinder chamber of the second compression mechanism.

  According to the present invention, it is possible to suppress the supercharging loss due to the provision of the switching means for switching between the compression operation and the non-compression operation according to the load with respect to the two-cylinder rotary compressor, and to improve the operation efficiency. There is an effect.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a cross-sectional structure of a two-cylinder rotary compressor R and a configuration of a refrigeration cycle including the rotary compressor R.
First, a description will be given of a two-cylinder rotary compressor R. Reference numeral 1 denotes a hermetic case. A lower part of the hermetic case 1 is provided with a compression mechanism 2 described later, and an upper part is provided with an electric motor unit 3. The electric motor unit 3 and the compression mechanism 2 are connected via a rotating shaft 4. The electric motor unit 3 is connected to an inverter 30 that varies the operating frequency, and is electrically connected to a control unit 40 that controls the inverter 30 via the inverter 30.

The compression mechanism body 2 includes a first compression mechanism portion 5 and a second compression mechanism portion 6 that are disposed below the rotary shaft 4 with an intermediate partition plate 7 interposed therebetween. Each compression mechanism part 5 and 6 is provided with the 1st cylinder 8A and the 2nd cylinder 8B.
A main bearing 9 is superposed on the upper surface portion of the first cylinder 8A, and is fixed to the cylinder 8A via a mounting bolt together with the valve cover a. A secondary bearing 11 is superimposed on the lower surface portion of the second cylinder 8B, and is fixed to the second cylinder 8B together with the valve cover b via a mounting bolt.

The rotary shaft 4 integrally includes two eccentric portions 4a and 4b that penetrate through the cylinders 8A and 8B and have a phase difference of about 180 °. Each eccentric part 4a, 4b has the same diameter as each other, and is assembled so as to be located in each cylinder 8A, 8B inner diameter part. Eccentric rollers 13a and 13b having the same diameter are fitted to the peripheral surfaces of the eccentric parts 4a and 4b.
The first cylinder 8A and the second cylinder 8B have upper and lower surfaces defined by the intermediate partition plate 7, the main bearing 9 and the sub-bearing 11, and cylinder chambers 14a and 14b are formed in the respective interiors. The cylinder chambers 14a and 14b are formed to have the same diameter and height, and the eccentric rollers 13a and 13b are accommodated in the cylinder chambers 14a and 14b so as to be eccentrically rotatable.

The cylinders 8A and 8B are provided with vane chambers 22a and 22b communicating with the cylinder chambers 14a and 14b. In each of the vane chambers 22a and 22b, the vanes 15a and 15b are accommodated so as to protrude and retract with respect to the cylinder chambers 14a and 14b.
FIG. 2 is an exploded perspective view showing the first cylinder 8A in the first compression mechanism section 5 and the second cylinder 8B in the second compression mechanism section 6. As shown in FIG.
The vane chambers 22a and 22b are integrally connected to vane storage grooves 23a and 23b in which both side surfaces of the vanes 15a and 15b are slidably movable and end portions of the vane storage grooves 23a and 23b. It consists of vertical hole parts 24a and 24b in which the rear end part is accommodated. The first cylinder 8A is provided with a lateral hole 25 that communicates the outer peripheral surface with the vane chamber 22a, and the spring member 26 is accommodated therein. This spring member 26 is interposed between the back side end surface of the vane 15a and the inner peripheral surface of the sealing case 1, and applies a resilient force (back pressure) to the vane 15a to bring the tip edge into contact with the eccentric roller 13a. It is.

No member other than the vane 15b is accommodated in the vane chamber 22b on the second cylinder 8B side. However, as will be described later, the setting environment of the vane chamber 22b and the action of the pressure switching mechanism (switching means) K are affected. Accordingly, the tip edge of the vane 15b is brought into contact with the eccentric roller 13b. The tip edges of the vanes 15a and 15b are formed in a semicircular shape in plan view, and can make line contact with the circumferential walls of the circular eccentric rollers 13a and 13b in plan view regardless of the rotation angle of the eccentric roller 13a.
When the eccentric rollers 13a and 13b rotate eccentrically along the inner peripheral walls of the cylinder chambers 14a and 14b, the vanes 15a and 15b reciprocate along the vane housing grooves 23a and 23b, and the rear end of the vane is a vertical hole. The action | operation which can freely advance / retreat from 24a, 24b can be performed. As described above, a part of the outer shape of the second cylinder 8B is exposed in the sealed case 1 due to the relationship between the outer dimension of the second cylinder 8B and the outer diameter of the intermediate partition plate 7 and the auxiliary bearing 11. .

The exposed portion of the second cylinder 8B to the sealed case 1 is designed to correspond to the vane chamber 22b, and the vane chamber 22b and the rear end portion of the vane 15b directly receive the internal pressure of the case. Since the second cylinder 8B and the vane chamber 22b are structures, there is no influence even if the pressure in the case is applied, but the vane 15b is slidably accommodated in the vane chamber 22b and the rear end thereof is the vane chamber 22b. Since it is located in the vertical hole 24b, it receives the pressure in the case directly.
The tip of the vane 15b faces the second cylinder chamber 14b, and the vane tip receives the pressure in the cylinder chamber 14b. Eventually, the vane 15b is configured to move in a direction from a higher pressure to a lower pressure according to the mutual pressure received by the front end and the rear end.

  As shown in FIG. 1 again, a discharge pipe 18 is connected to the upper end of the sealed case 1. The discharge pipe 18 is connected to the accumulator 17 via a condenser 19, an expansion mechanism 20 and an evaporator 21. Suction pipes 16 a and 16 b constituting a suction passage for the compressor R are connected to the bottom of the accumulator 17. One suction pipe 16a penetrates the sealed case 1 and the side of the first cylinder 8A, and communicates directly with the first cylinder chamber 14a. The other suction pipe 16b penetrates the sealed case 1 and the side of the second cylinder 8B, and communicates directly with the second cylinder chamber 14b.

A branch pipe P is provided that branches from a middle portion of the discharge pipe 18 that communicates the compressor R and the condenser 19 and is connected to a middle part of the suction pipe 16b. On-off valve 28 is provided. In the suction pipe 16b, a second on-off valve 29 is provided on the upstream side of the connection part c with the branch pipe P. Each of the first on-off valve 28 and the second on-off valve 29 is an electromagnetic valve, and is controlled to open and close in accordance with an electric signal from the control unit 40.
In this way, the pressure switching mechanism (switching means) K is constituted by the suction pipe 16b, the branch pipe P, the first on-off valve 28 and the second on-off valve 29 connected to the second cylinder chamber 14b. . In accordance with the switching operation of the pressure switching mechanism K, the suction pressure (low pressure) or the discharge pressure (high pressure) is guided to the cylinder chamber 14b of the second cylinder 8B.

In particular, the first suction pipe 16b communicating with the second cylinder chamber 14b has a first pressure switching mechanism K as compared with the entire length of the first suction pipe 16a communicating with the first cylinder chamber 14a. Since the branch pipe P having the open / close valve 28 is connected or the second open / close valve 29 is provided, the entire length of the second suction pipe 16b itself becomes long.
Therefore, a buffer 50 that is a space volume is provided in the second suction pipe 16b on the downstream side of the connection portion c with the branch pipe P and between the second suction pipe 16b and the second cylinder chamber 8B. The buffer 50 is a tank or cylindrical body having an inner diameter larger than at least the diameter of the suction pipe 16b.

Next, the operation of the refrigeration cycle apparatus provided with the above-described two-cylinder rotary compressor R will be described.
(1) When normal operation (full capacity operation) is selected:
The control unit 40 controls to close the first on-off valve 28 of the pressure switching mechanism K and to open the second on-off valve 29. Then, the control unit 40 sends an operation signal to the electric motor unit 3 via the inverter 30. The rotating shaft 4 is driven to rotate, and the eccentric rollers 13a and 13b rotate eccentrically in the cylinder chambers 14a and 14b.

In the first cylinder 8A, the vane 15a is always elastically pressed and urged by the spring member 26, and the tip edge of the vane 15a is in sliding contact with the peripheral wall of the eccentric roller 13a so that the inside of the first cylinder chamber 14a becomes a suction chamber and a compression chamber. Divide into two. The refrigerant gas is sucked from the accumulator 17 through the suction pipe 16a into the first cylinder chamber 14a to be filled.
Along with the eccentric rotation of the eccentric roller 13a, the partitioned volume of the cylinder chamber 14a decreases, and the sucked gas is gradually compressed. When the rotating shaft 4 is continuously rotated and the gas is compressed and rises to a predetermined pressure, a discharge valve (not shown) is opened. The high-pressure gas is discharged into the sealed case 1 through the valve cover a, and finally discharged from the discharge pipe 18 above the sealed case.

  On the other hand, since the first on-off valve 28 constituting the pressure switching mechanism K is closed, the discharge pressure (high pressure) is not guided to the second cylinder chamber 14b. Since the second on-off valve 29 is opened, the low-pressure evaporative refrigerant is guided from the accumulator 17 to the second cylinder chamber 14b. While the second cylinder chamber 14b is in a suction pressure (low pressure) atmosphere, the vane chamber 22b is exposed in the sealed case 1 and is under a discharge pressure (high pressure). The tip of the vane 15b has a low pressure condition, and the rear end has a high pressure condition, and there is a differential pressure at the front and rear ends.

Under the influence of this differential pressure, the tip of the vane 15b is pressed and urged so as to be in sliding contact with the eccentric roller 13b, and the same compression action as that of the first cylinder chamber 14a is also performed in the second cylinder chamber 14b. Eventually, a full capacity operation is performed in which the compression action is performed in both the first cylinder chamber 14a and the second cylinder chamber 14b.
The high-pressure gas discharged from the sealed case 1 through the discharge pipe 18 is led to the condenser 19 to be condensed and liquefied, adiabatically expanded by the expansion mechanism 20, and the evaporator 21 takes away latent heat of evaporation from the heat exchange air and cools it. It works. The evaporated refrigerant is separated into gas and liquid by the accumulator 17, and is again sucked into the first and second cylinder chambers 14a and 14b of the compressor R from the suction pipes 16a and 16b and circulates in the above-described path.

(2) When special operation (half-capacity operation) is selected:
When the special operation (operation that halves the compression capacity) is selected, the control unit 40 performs switching to open the first on-off valve 28 and close the second on-off valve 29. In the first cylinder chamber 14a, the normal compression action described above is performed, and the high-pressure gas discharged into the sealed case 1 is filled. Part of the high-pressure gas discharged from the discharge pipe 18 is diverted to the branch pipe P and introduced into the second cylinder chamber 14b via the first on-off valve 28 and the suction pipe 16b, and the cylinder chamber 14b has a high pressure. Become.

While the second cylinder chamber 14b is in the discharge pressure (high pressure) atmosphere, the vane chamber 22b remains in the same situation as the high pressure in the case. Therefore, the vane 15b is affected by the high pressure at both the front and rear ends, and there is no differential pressure at the front and rear ends. The vane 15b maintains a stopped state at a position separated from the outer peripheral surface of the roller 13b, and no compression action is performed in the second cylinder chamber 14b.
Eventually, only the compression action in the first cylinder chamber 14a is effective, and the operation is performed with half the capacity. Since the inside of the second cylinder chamber 14b is at a high pressure, there is no leakage of compressed gas from the sealed case 1 into the second cylinder chamber 14b, and no loss is caused thereby. Therefore, it is possible to operate with half the capacity without lowering the efficiency.

As described above, compared to the first suction pipe 16a connected to the first compression mechanism section 5, the second suction pipe 16b connected to the second compression mechanism section 6 is provided with a pressure switching mechanism K. Since the member (2nd on-off valve 29 grade | etc.,) To comprise is provided, full length will become long.
As shown in FIG. 4A, a supercharging loss occurs at a low operating frequency F as it is, and the operating efficiency decreases near the operating frequency F. Here, a buffer (space volume) 50 is provided in the middle of the second suction pipe 16b communicating with the accumulator 17 and the second cylinder chamber 14b and downstream of the connection part c with the branch pipe P. Yes.

  That is, the low-pressure refrigerant led from the accumulator 17 is temporarily collected in the buffer 50 and then led to the second cylinder chamber 14b. As for the flow of the refrigerant, the pressure is relaxed by the buffer 50, and it is considered as if a new flow comes out of the buffer 50 as if it is in a divided state. For this reason, the length of the suction pipe between the accumulator 17 and the buffer 50 is excluded from the length of the suction pipe that determines the operating frequency causing the supercharging loss, and the length of the substantial suction pipe is shortened. Therefore, the operating frequency causing supercharging loss can be increased.

FIG. 3 is a diagram illustrating the configuration of the pressure switching mechanism Ka according to the second embodiment of the present invention. The configurations of the two-cylinder rotary compressor R and the refrigeration cycle are exactly the same as those described above, and the same numbers are assigned and a new description is omitted. Note that the inverter circuit 30 and the control unit 40 are omitted.
The pressure switching mechanism Ka includes branch pipes P that communicate with the discharge pipe 18, suction pipes 16c that guide and guide the low-pressure gas evaporated from the accumulator 17, and end portions of the suction pipes 16b that communicate with the second cylinder chamber 14b. Comprises a three-way switching valve 35 having a port to which is connected.

When the full capacity operation is selected, the three-way switching valve 35 communicates the accumulator 17 and the second cylinder chamber 14b via the suction pipes 16c and 16b. Therefore, the second cylinder chamber 14b has a low pressure, and a differential pressure is generated between the second cylinder chamber 14b and the high-pressure vane chamber 22b. The vane 15b receives back pressure, contacts the eccentric roller 13b, and reciprocates to perform a compression action.
When the half-capacity operation is selected, the three-way switching valve 35 communicates with the second cylinder chamber 14b via the branch pipe P and the suction pipe 16b, and the accumulator 17 is bypassed. The high-pressure refrigerant is guided to the second cylinder chamber 14b and becomes high pressure. Under the same conditions as the high-pressure vane chamber 22b, the vane 15b does not move its position. Accordingly, the half capacity operation of only the first cylinder chamber 14a is performed.

During normal operation, the low-pressure refrigerant is temporarily collected in the buffer 50, and the pressure of the refrigerant is relieved by the buffer 50. As a result, the refrigerant 50 is considered to be in a divided state and a new flow comes out of the buffer 50. For this reason, the length of the suction pipe between the accumulator 17 and the buffer 50 is excluded from the length of the suction pipe that determines the operating frequency causing the supercharging loss, and the length of the suction pipe is substantially shortened. The operating frequency that causes supercharging loss can be increased.
As described above with reference to FIG. 4B, the supercharging operation frequency F determined from the length of the suction pipe 16b may be made larger than the maximum operation frequency Fmax as follows. That is, the length Ls of the suction pipe 16b from the buffer 50 to the second cylinder chamber 14b is set so as to satisfy the following expression (1).

Ls <C / 4Fa−V / S (1)
Where C: sound speed, Fa: 1.1 × Fmax, Fmax: maximum operating frequency,
V: volume of the second cylinder chamber 14b, S: area of the suction pipe 16b.
Thus, by setting the operating frequency F at which supercharging occurs to be greater than the maximum operating frequency Fmax range, there is no supercharging loss within the range of the maximum operating frequency Fmax, and there is no performance degradation. A compressor can be provided.

Further, as described above with reference to FIG. 4C, the supercharging operation frequency F determined from the length of the suction pipe 16b may be set in the vicinity of the maximum operation frequency Fmax as follows. That is, the length Ls of the suction pipe 16b from the buffer 50 to the second cylinder chamber 14b is set so as to satisfy the following expression (2).
Ls = C / 4Fb−V / S (2)
Where C: sound velocity, Fb: (0.8 to 1.1) × Fmax, Fmax: maximum frequency,
V: volume of the second cylinder chamber 14b, S: area of the suction pipe 16b.

By setting the operating frequency F at which supercharging occurs in the vicinity of the maximum operating frequency Fmax, the capacity can be increased due to the supercharging effect near the maximum operating frequency Fmax. On the other hand, when the operating frequency is lower than that, it is possible to provide a two-cylinder rotary compressor that suppresses the supercharging loss and does not decrease the operating efficiency.
5A and 5B show the relationship between the operating efficiency of the two-cylinder rotary compressor R and the buffer 50 at the operating frequency F at which supercharging occurs. From the results shown in FIG. 5, the efficiency reduction due to the supercharging loss can be suppressed by setting the buffer 50 so as to satisfy the following expressions (3) and (4).

Db ≧ 2Ds (3)
Lb = (0.2-1) × Ls (4)
Where Db: diameter of the buffer 50, Lb: length of the buffer 50,
Ds: pipe diameter of the suction pipe 16b, Ls: length of the suction pipe 16b from the buffer 50 to the second cylinder chamber 14b.
Further, as shown in FIG. 3, the buffer 50 is fixed to the accumulator 17 by welding or is fixed using a band. As a result, it is possible to reliably prevent damage to the piping system including the buffer 50 due to vibration associated with the operation of the compressor R and vibration or impact during transportation as a product.

Further, as shown in FIG. 3, a filter 60 a as a foreign matter capturing means is provided in the buffer 50. The filter 60 a may be provided in any of the suction passages (suction pipes) from the second cylinder chamber 14 b other than the buffer 50 to the three-way switching valve 35.
Or you may provide the filter 60b in the middle part of the branch pipe P branched from the middle part of the discharge pipe 18 of the compressor R. FIG.
In addition, when the filter 60a is provided in the buffer 50, since the cross-sectional area of the buffer 50 is large, the pressure loss of the refrigerant | coolant by the filter 60a can be reduced.

During the non-compression operation (operation stop) in the second cylinder chamber 14b, the high-pressure refrigerant introduced into the cylinder chamber 14b does not pass through the accumulator 17, so that the foreign matter contained in the high-pressure refrigerant as it is together with the high-pressure refrigerant is added to the second cylinder Although there is a possibility of being introduced into the chamber 14b, the provision of the filters 60a and 60b at the above-described sites can capture foreign substances contained in the high-pressure refrigerant, contributing to an improvement in reliability.
As shown in FIG. 3, a part of the suction pipes 16 b and 16 c and the buffer 50 are covered with a heat insulating material 65. As described above, the suction pipes 16b and 16c connected to the second cylinder chamber 14b switched according to the magnitude of the load are longer than the suction pipe 16a connected to the first cylinder chamber 14a that always performs the compression operation. Therefore, the refrigerant guided through the suction pipes 16b and 16c is easily heated, and the performance is deteriorated. By covering the suction pipes 16b and 16c and the buffer 50 with the heat insulating material 65, it is possible to provide a two-cylinder rotary compressor R that suppresses refrigerant heating and does not deteriorate in performance.

The configuration of the pressure switching mechanisms K and Ka for switching the suction pressure and the discharge pressure with respect to the second cylinder chamber 14b is not limited to the one described above, and instead of the second on-off valve 29. A check valve may be provided.
Or like the 1st compression mechanism part 5, after using the spring member 26 for the vane chamber 22b also in the 2nd compression mechanism part 6, the high pressure and the low pressure with respect to the cylinder chamber 8B of the 2nd mechanism part 6 are used. You may comprise so that a connection may be switched.
In this case, during the full capacity operation, the same action as the cylinder chamber 8A of the first compression mechanism section 5 is performed in the cylinder chamber 8B of the second mechanism section 6, so that the compression efficiency can be improved. However, the vane 15b is pressed and urged by the spring member 26 to reciprocate even during half-capacity operation, causing work and reducing compression efficiency. However, the first compression mechanism 5 and the second compression are reduced. Since the mechanism parts 6 have the same configuration, the mechanism is simple.

Furthermore, the spring member 26 is provided on the vane 15a, 15b side of both the compression mechanism portions 5, 6 and the vane chamber 22b of the second compression mechanism portion 6 is sealed so as to be guided to the cylinder chamber 14b at the time of startup, for example. A lower pressure than the high pressure of the refrigeration cycle to be used may be guided to the sealed vane chamber 22b.
At the time of startup, there is a certain amount of time until the inside of the sealed case 1 reaches a predetermined high pressure state from the low pressure state. In the configuration of the vane chamber 22b exposed to the pressure in the above-described sealed case 1, full capacity operation is selected. However, a pressure difference is unlikely to occur with the cylinder chamber 14b. Therefore, if the vane chamber 22b is sealed and a low pressure is introduced at the time of startup, the vane 15b is pulled away by the pressure difference and the compression efficiency is good at the time of startup as in the case where the spring member 26 is not provided. However, since the vane chamber 22b has a sealed structure, it is mechanically complicated, and means for introducing a low pressure is required.
The rotary hermetic compressor R and the refrigeration cycle apparatus provided with this compressor are not limited to the above-described configuration, and various modifications can be made within the scope of the present invention. Of course.

The longitudinal cross-sectional view and refrigeration cycle block diagram of the 2 cylinder type rotary compressor which concern on 1st Embodiment in this invention. The disassembled perspective view of a part of compression mechanism based on the embodiment. The longitudinal cross-sectional view and refrigeration cycle block diagram of the 2 cylinder type rotary compressor which concern on 2nd Embodiment in this invention. The characteristic figure of volumetric efficiency and driving efficiency with respect to mutually different driving frequencies. FIG. 4 is a characteristic diagram of the diameter and the total length of the suction pipe with respect to the buffer and the operation efficiency for these.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sealing case, 3 ... Electric motor part, 5 ... 1st compression mechanism part, 6 ... 2nd compression mechanism part, R ... 2 cylinder type rotary compressor, 14a ... 1st cylinder chamber, 14b ... 2nd Cylinder chamber, K ... pressure switching mechanism (switching means), 16a ... first suction pipe, 16b ... second suction pipe, 50 ... buffer (space volume), 60a, 60b ... filter (foreign matter capturing means).

Claims (1)

Form part of a refrigeration cycle, an electric motor unit in the sealed case, Ri Na houses the first compression mechanism and the second compression mechanism portion connected with the motor unit, the first compression mechanism A two-cylinder rotary compressor that discharges gas compressed by the second compression mechanism and the second compression mechanism into a sealed case to make the case high pressure ;
A refrigeration cycle comprising a suction passage that communicates with each compression mechanism of the two-cylinder rotary compressor and introduces low-pressure refrigerant into the cylinder chamber of each compression mechanism via an accumulator that forms part of the refrigeration cycle. In the device
The first compression mechanism portion and the second compression mechanism portion of the two-cylinder rotary compressor are as follows:
A cylinder having a cylinder chamber in which each eccentric roller is accommodated in an eccentric rotatable manner;
A vane provided on the cylinder, the tip edge of which is pressed and biased to contact the circumferential surface of the eccentric roller, divides the cylinder chamber into two along the rotational direction of the eccentric roller, and the rear side end of each vane. A vane chamber to house,
Provided in a suction passage communicating with the cylinder chamber of the second compression mechanism section, and switching means for guiding suction pressure or discharge pressure to the cylinder chamber of the cylinder of the second compression mechanism section ,
The vane provided in the cylinder of the first compression mechanism is pressed and urged by a spring member provided in the vane chamber,
The vane provided in the cylinder of the second compression mechanism section is configured such that when suction pressure is guided to the cylinder chamber of the second compression mechanism section by the switching means, the pressure in the case and the cylinder chamber are guided to the vane chamber. The leading edge of the vane is pressed and urged to come into contact with the circumferential surface of the eccentric roller by the pressure difference from the suction pressure introduced to the suction pressure, and the discharge pressure is applied to the cylinder chamber of the second compression mechanism by the switching means. When guided, the pressure in the case guided to the vane chamber and the discharge pressure guided to the cylinder chamber are balanced, and the pressure is balanced at the front and rear end portions of the vane, and the leading edge of the vane is the eccentric roller. To be separated from the circumferential surface of the
The refrigeration cycle apparatus further comprises a space volume provided in a midway portion of the suction passage connecting the accumulator and the cylinder chamber of the second compression mechanism.

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