JP4523902B2 - Two-cylinder rotary compressor and refrigeration cycle apparatus - Google Patents

Description

  The present invention relates to a two-cylinder rotary compressor and a refrigeration cycle apparatus, for example, an air conditioner, including the two-cylinder rotary compressor.

[Patent Document 1] discloses a two-cylinder rotary compressor. In the compressor section, the main bearing is attached to the upper end surface of the upper cylinder, and the auxiliary bearing is attached to the lower end surface of the lower cylinder. The high-pressure gas compressed in the compression chamber in the upper cylinder is discharged from the discharge port provided in the main bearing into the sealed container via the discharge valve. The high-pressure gas compressed in the compression chamber in the lower cylinder is discharged from a discharge port provided in the auxiliary bearing into the sealed container via a discharge valve.
By the way, in this type of two-cylinder rotary compressor, a problem arises due to the setting of the distance from the axis of the rotating shaft to the center of the discharge port provided in the main bearing and the sub-bearing due to the configuration of the compressor section with respect to the electric motor section. There is a case. However, [Patent Document 1] does not describe the above distance, and in the drawing, the distance from the axis of the rotating shaft to the center of the discharge port is shown identically on the main bearing side and the sub bearing side. .
JP 11-210626 A

That is, in this type of compressor, the suction stroke and the compression stroke are continuously performed as the roller moves in the compression chamber of each cylinder. Since the discharge valve opens the discharge port at the end of the compression stroke, the high-pressure gas is discharged from the compression chamber. However, not all the high-pressure gas is discharged from the compression chamber, and it is inevitable that a part remains in the discharge port.
The high-pressure gas remaining in the discharge port expands during the next suction stroke, so that the amount of suction gas newly introduced into the compression chamber is reduced and the capacity is lowered. Since the volume (passage volume) of the discharge port becomes a so-called top clearance and leads to a decrease in volume efficiency, it is necessary to make the volume of the discharge port as small as possible.
However, the said compressor part is connected with the electric motor part via the rotating shaft, and the main bearing attached to an upper cylinder exists in the position adjacent to an electric motor part. And since the main bearing must pivot about the rotating shaft, the volume setting of the discharge port should not adversely affect the shaft reliability. On the other hand, the auxiliary bearing attached to the lower cylinder is located farthest from the motor portion, and supports the rotating shaft while being less affected by the motor portion.

  The present invention has been made paying attention to the above circumstances, and the object of the present invention is to set the discharge port provided in the sub-bearing and the position of the discharge port provided in the main bearing to be the best condition, volume A two-cylinder rotary compressor capable of preventing reduction in efficiency and improving compression efficiency and improving shaft reliability with respect to the rotating shaft, and a refrigeration cycle circuit using the two-cylinder rotary compressor The present invention intends to provide a refrigeration cycle apparatus capable of improving the refrigeration efficiency.

In order to achieve the above object, a two-cylinder rotary compressor according to the present invention accommodates a compressor part composed of two sets of compression mechanisms connected to an electric motor part and a rotating shaft in a sealed container, and the compressor part is an electric motor. The main bearing, the first compression mechanism, the intermediate partition plate, the second compression mechanism, and the sub-bearing are combined in this order from the part side. The first compression mechanism and the second compression mechanism rotate the cylinder and roller eccentrically, respectively. A cylinder chamber that is freely accommodated, and a blade that divides the cylinder chamber in half along the rotation direction of the roller by abutting the tip edge with the circumferential surface of the roller,
The main bearing includes a flange portion attached to the cylinder of the first compression mechanism, and a boss portion integrally formed with the flange portion and pivotally supporting a part of the rotary shaft. The first discharge port is provided with a concave portion to which the central portion is attached, and the thin portion formed between the concave portion and the other surface of the flange portion is provided with the concave portion and the central axis aligned with each other and is opened and closed by the first discharge valve With
The auxiliary bearing is composed of a flange portion attached to the cylinder of the second compression mechanism, and a boss portion that is integrally formed with the flange portion and pivotally supports a part of the rotary shaft. A recessed portion to be attached is provided, and a second discharge port which is provided on the thin wall portion formed between the recessed portion and the other surface of the flange portion so as to coincide with the central axis and is opened and closed by the second discharge valve is provided. Prepared,
Recess of the main bearing is provided without cutting into the boss portion of the main bearing, the recess of the auxiliary bearing that is provided so as bite into the boss portion of the auxiliary bearing, the second discharge port from the center axis of the rotary shaft Is set to be smaller than the distance (R1) from the axis of the rotation axis to the center of the first discharge port (R2 <R1) ,
With the setting of the distance (R2), the second discharge port opens with an area of 70% or more with respect to the second cylinder .
In order to achieve the above object, a refrigeration cycle apparatus according to the present invention forms a refrigeration cycle circuit by connecting the above-described two-cylinder rotary compressor, a condenser, an expansion device, and an evaporator via a refrigerant pipe.

According to the two-cylinder rotary compressor of the present invention, it is possible to prevent the volumetric efficiency from being lowered and to obtain an improvement in the compression efficiency.
And according to the refrigeration cycle apparatus which comprises a refrigeration cycle circuit using the 2-cylinder type rotary compressor of this invention, there exists an effect which can obtain the improvement of refrigeration efficiency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a cross-sectional structure of a two-cylinder rotary compressor C and a configuration of a refrigeration cycle circuit S including the two-cylinder rotary compressor C. (In order to avoid complications in the drawings, some components are not described with reference numerals only for explanation.)
First, a description will be given of the two-cylinder rotary compressor C. Reference numeral 1 denotes a hermetic container, and the compressor part 2 is accommodated in the lower part of the hermetic container 1 and the motor part 3 is accommodated in the upper part. The compressor unit 2 and the motor unit 3 are connected via a rotating shaft 4.
The electric motor unit 3 includes a stator 5 that is fixed to the inner surface of the hermetic container 1 and a rotor 6 that is disposed inside the stator 5 with a predetermined gap and into which the rotating shaft 4 is inserted. Yes. The electric motor unit 3 is provided outside the sealed container 1 and is electrically connected to the control unit 40. The control unit 40 includes an inverter circuit, for example, and can control the operation frequency.

The compressor unit 2 includes a first compression mechanism 2A on the upper side (motor unit 2 side) and a second compression mechanism 2B on the lower side (reverse motor unit 2 side). The first compression mechanism 2A and the second compression mechanism 2B are respectively provided with a first cylinder 8A and a second cylinder 8B that are disposed below the rotary shaft 4 with an intermediate partition plate 7 interposed therebetween. I have.
The main bearing 9 is overlaid on the upper surface of the first cylinder 8A, and is fixed to the first cylinder 8A via a mounting bolt together with the valve cover a. The main bearing 9 is integrally formed with a flange portion 9a directly attached to the first cylinder 8A and a boss portion 9b provided at the center position of the flange portion 9a and pivotally supporting the intermediate portion of the rotary shaft 4.

A concave portion 10a is provided in a predetermined portion of the main bearing 9 covered with the valve cover a of the flange portion 9a, and the first discharge valve 11a is attached to the concave portion 10a. A first discharge port 12a is provided between the bottom surface of the recess 10a and the bottom surface (lower surface) of the flange portion 9a. The discharge port 12a is opened and closed by the first discharge valve 11a. . The central axis of the recess 10b and the central axis of the second discharge port 12b coincide with each other.
On the other hand, the auxiliary bearing 13 is attached to the lower surface of the second cylinder 8B, and is attached and fixed to the first cylinder 8A through the attachment bolt together with the valve cover b. The auxiliary bearing 13 is integrally formed with a flange portion 13a that is directly attached to the second cylinder 8B and a boss portion 13b that is provided at the center of the flange portion and pivotally supports the lower portion of the rotary shaft 4.

A concave portion 10b is provided at a predetermined portion of the flange portion 13a of the auxiliary bearing 13 covered with the valve cover b, and the second discharge valve 11b is attached to the concave portion 10b. A second discharge port 12b is provided between the bottom surface of the recess 10b and the bottom surface (upper surface) of the flange portion 13a, and the discharge port 12b is opened and closed by the second discharge valve 11b. ing. The central axis of the recess 10b and the central axis of the second discharge port 12b coincide with each other.
The configuration and setting positions of the recess 10a and the first discharge port 12a in the first cylinder 8A and the configuration and setting positions of the recess 10b and the second discharge port 12b in the second cylinder 8B will be described later. .
On the other hand, the rotating shaft 4 penetrates through the insides of the first and second cylinders 8A and 8B, and integrally includes two eccentric portions 4a and 4b formed with a phase difference of about 180 °. The eccentric portions 4a and 4b have the same diameter as each other, and are assembled so as to be located in the inner diameter portions of the cylinders 8A and 8B. Eccentric rollers 14a and 14b having the same diameter are fitted on 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 auxiliary bearing 13, and have a first cylinder chamber 15a and a second cylinder chamber 15b inside. Is formed. The first and second cylinder chambers 15a and 15b are formed to have the same diameter and height, and the eccentric rollers 14a and 14b are accommodated in the cylinder chambers 15a and 15b so as to be eccentrically rotatable.
The height of each eccentric roller 14a, 14b is formed substantially the same as the height of each cylinder chamber 15a, 15b. Accordingly, the eccentric rollers 14a and 14b have a phase difference of 180 ° from each other, but are set to the same excluded volume in the cylinder chamber by rotating eccentrically in the cylinder chambers 15a and 15b.

Further, each of the cylinders 8A and 8B is provided with blade chambers 16a and 16b communicating with the first and second cylinder chambers 15a and 15b. In each of the blade chambers 16a and 16b, blades 17a and 17b are accommodated so as to protrude and retract with respect to the first cylinder chamber 15a and the second cylinder chamber 15b, respectively.
FIG. 2 is an exploded perspective view showing a part of each of the first compression mechanism 2A and the second compression mechanism 2B constituting the compressor unit 2. As shown in FIG.
The blade chambers 16a and 16b are integrally connected to the blade housing grooves 18a and 18b in which both side surfaces of the blades 17a and 17b are slidably movable and the ends of the blade housing grooves 18a and 18b. It consists of vertical hole portions 19a and 19b in which rear end portions are accommodated.

In particular, the second cylinder 8B is provided with a lateral hole 20 that communicates the outer peripheral surface with the blade chamber 16b, and a spring member 21 is inserted therein. The lateral hole 20 after the spring member 21 is inserted is closed by a plug 22. Accordingly, the spring member 21 is interposed between the rear end face of the blade 17b and the plug body 22, and applies a resilient force (back pressure) to the blade 17b so that the tip portion contacts the eccentric roller 14a. It is.
The blade chamber 16a on the first cylinder 8A side does not contain any members other than the blade 17a. However, as will be described later, the setting environment of the blade chamber 16a and a capacity variable mechanism (capacity switching control means) to be described later. According to the action of K, the tip of the blade 17a is brought into contact with the eccentric roller 14a.
The tips of the blades 17a and 17b are formed in a semicircular shape in plan view, and can make line contact with the circumferential walls of the circular eccentric rollers 14a and 14b in plan view. When the eccentric rollers 14a and 14b rotate eccentrically along the inner peripheral walls of the first and second cylinder chambers 15a and 15b, the blades 17a and 17b reciprocate along the blade housing grooves 18a and 18b, and each cylinder chamber 15a. 15b are divided into a suction chamber and a compression chamber. In this state, the rear end portions of the blades 17a and 17b can advance and retract from the vertical hole portions 19a and 19b.

As described above, the blade chamber 16a provided in the first cylinder 8A is provided in the hermetic container 1 from the relationship between the outer shape of the first cylinder 8A and the outer dimensions of the intermediate partition plate 7 and the main bearing 9. Exposed to. Accordingly, the blade chamber 16a and the rear end portion of the blade 17a directly receive the pressure in the container.
In particular, since the first cylinder 8A and the blade chamber 16a are structures, there is no influence even if they are subjected to pressure inside the case, but the blade 17a is slidably accommodated in the blade chamber 16a and the rear end portion is Since it is located in the vertical hole portion 19a of the blade chamber 16a, it receives the internal pressure of the container directly.

Further, the tip of the blade 17a faces the first cylinder chamber 15a, and the blade tip receives the pressure in the cylinder chamber 15a. Eventually, the blade 17a is configured to move from the higher pressure to the lower pressure according to the mutual pressure received by the front end and the rear end.
A holding mechanism 23 is provided on the outer peripheral surface side of the vertical hole portion 19a in the blade chamber 16a of the first cylinder 8A. The holding mechanism 23 moves the blade 17a from the eccentric roller 14a with a force smaller than the differential pressure between the suction pressure guided to the first cylinder chamber 15a and the pressure in the sealed container 1 guided to the blade chamber 16a during normal operation. Energize in the pulling direction. As the holding mechanism 23, a permanent magnet, an electromagnet, or a tension spring that is an elastic body is employed.

  In this way, the compressor unit 2 is configured. Generally, the compressor unit 2 includes, from the motor unit 3 side, the main bearing 9, the first compression mechanism 2A, the intermediate partition plate 7, and the like. The second compression mechanism 2B and the auxiliary bearing 13 are combined in order. Therefore, the main bearing 9 is provided closest to the electric motor unit 3, and the auxiliary bearing 13 is provided farthest.

The two-cylinder rotary compressor C is incorporated in a refrigeration cycle circuit S constituting a refrigeration cycle apparatus. That is, a refrigerant pipe P is connected to the upper end portion of the sealed container 1, and this refrigerant pipe P is connected to an accumulator 28 via a condenser 25, an expansion mechanism (expansion device) 26 and an evaporator 27. .
A first suction refrigerant pipe Pa and a second suction refrigerant pipe Pb are connected to the bottom of the accumulator 28. A check valve 29 and a three-way switching valve 30, which will be described later, are provided in the middle of the first suction refrigerant pipe Pa, and the tip is connected to a suction hole that penetrates the sealed container 1 and is provided in the first cylinder 8A. The Therefore, the first suction refrigerant pipe Pa communicates directly with the first cylinder chamber 15a. The second suction refrigerant pipe Pb penetrates the sealed container 1 and is connected to a suction hole provided in the second cylinder 8B, and communicates directly with the second cylinder chamber 15b.

Further, the high-pressure introduction pipe 31 is branched from the middle part of the refrigerant pipe P connected to the upper part of the two-cylinder rotary compressor C. The high pressure introduction pipe 31 is provided with an electromagnetic opening / closing valve 32 so that the high pressure introduction pipe 31 can be freely opened and closed. The other end of the high pressure introduction pipe 31 is connected to the three-way switching valve 30 provided in the first suction refrigerant pipe Pa.
A first suction in which the check valve 29 and the three-way switching valve 30 are provided, the high-pressure introduction pipe 31 provided with the electromagnetic opening / closing valve 32 and connected to the three-way switching valve 30, the accumulator 28 and the first cylinder chamber 15a. The capacity variable mechanism K is configured by the configuration of the blade 17a and the blade chamber 16a in the refrigerant pipe Pa and the first compression mechanism 2A.

That is, according to the opening / closing operation of the electromagnetic opening / closing valve 32 provided in the variable capacity mechanism K and the switching direction of the three-way switching valve 30, the high-pressure gas discharged into the hermetic container 1 into the first cylinder chamber 15a as will be described later. The low pressure gas that has been guided or passed through the accumulator 28 is guided, and the blade 17a acts according to these conditions.
The high-pressure introduction pipe 31 is connected to the sealed container 1 as shown by a two-dot chain line in the figure, instead of branching from the middle part of the refrigerant pipe P, so that the open end faces the sealed container 1. Also good.
Next, on the basis of a partial cross-sectional view of the compressor section 2 in FIG. 3 and a top view of the auxiliary bearing 13 in FIG. 4, the configuration and position of the recess 10a and the discharge port 12a provided in the first cylinder 8A, and The form and position of the recess 10b and the discharge port 12b provided in the second cylinder 8B will be described in detail.

  Specifically, the distance R2 from the axis of the rotating shaft 4 to the center of the second discharge port 12b provided in the auxiliary bearing 13 is the first discharge port 12a provided in the main bearing 9 from the axis of the rotating shaft 4. It is set smaller than the distance R1 to the center (R2 <R1). The diameter φDb of the second discharge port 12b is set smaller than the diameter φDa of the first discharge port 12a (φDb <φDa).

That is, the concave portion 10a provided from the upper surface of the main bearing flange portion 9a is positioned at a distance R1 from the axis of the rotating shaft 4 to the center of the first discharge port 12a. Therefore, a part of the peripheral edge of the recess 10a is provided in parallel with a part of the peripheral surface of the boss part 9b without biting into the boss part 9b. Between the bottom surface of the recess 10a and the lower surface of the flange portion 9a, a thin portion d having a thickness capable of maintaining a minimum necessary rigidity is formed.
The concave portion 10a is provided with the first discharge port 12a whose central axes coincide with each other and penetrates the thin portion d. With the setting of the distance R1, a part of the first discharge port 12a faces the peripheral portion of the inner diameter of the first cylinder 8A. A discharge notch 33 is provided in the first cylinder 8A, and the first discharge port 12a is completely opened . The discharge notch 33 is cut obliquely from the upper surface of the first cylinder 8A to the inner peripheral surface of the cylinder 8A.

On the other hand, the concave portion 10b provided from the lower surface of the auxiliary bearing flange portion 13a has a concave portion for positioning the distance from the center of the rotating shaft 4 to the center as R2 together with the second discharge port 12b having the center axis aligned. 10b is provided to bite into not only the flange portion 13a but also a part of the peripheral surface of the boss portion 13b.
Between the bottom surface of the recess 10b and the top surface of the flange portion 13a, a thin-walled portion e having a minimum necessary thickness for maintaining rigidity is formed. The concave portion 10b is provided with the second discharge port 12b through the thin portion e. With the setting of the distance R2, the second discharge port 12b is completely opened without being engaged with the second cylinder 8B, and the second cylinder 8B has a discharge notch 33 in the first cylinder 8A. No processing is necessary.

Next, the operation of the two-cylinder rotary compressor C configured as described above and the operation of the refrigeration cycle circuit S including this compressor will be described.
When the air-conditioning load is heavy, such as when starting up, perform high capacity operation.
The control unit 40 closes the electromagnetic on-off valve 32 constituting the capacity variable mechanism K to cut off the flow of refrigerant in the high-pressure introduction pipe 31, and the three-way switching valve 30 is connected to the accumulator 28 and the first cylinder chamber 15a. The first suction refrigerant pipe Pa is opened so as to communicate with each other. Then, an operation start signal is sent to the motor unit 3. The rotary shaft 4 is rotationally driven, and the first compression mechanism 2A and the second compression mechanism 2B constituting the compressor unit 2 act simultaneously.
That is, the eccentric rollers 14a and 14b rotate eccentrically in the first cylinder chamber 15a and the second cylinder chamber 15b, respectively. In the second compression mechanism 2B, since the blade 17b is always elastically pressed and biased by the spring member 21, the tip edge of the blade 17b is slidably contacted with the peripheral wall of the eccentric roller 14b to move inside the second cylinder chamber 15b. Divide into suction chamber and compression chamber.
When the rolling contact position of the inner circumferential surface of the cylinder chamber 15b of the eccentric roller 14b is the blade housing groove 18b, the blade 17b is most retracted, and the space capacity of the second cylinder chamber 15b is maximized. The refrigerant gas is sucked into the second cylinder chamber 15b from the accumulator 28 through the second suction refrigerant pipe Pb .
As the eccentric roller 14b rotates eccentrically, the rolling contact position with respect to the inner peripheral surface of the second cylinder chamber 15b moves, and the volume of the compression chamber defined by the blade 17b decreases. Therefore, the gas previously introduced into the cylinder chamber 15b is gradually compressed. The rotating shaft 4 is continuously rotated, the capacity of the compression chamber in the second cylinder chamber 15b is further reduced, the gas is compressed, and the second discharge valve 11b is opened when the pressure rises to a predetermined pressure. The high-pressure gas is discharged into the sealed container 1 through the valve cover b, and is further guided to the refrigerant pipe P connected to the upper part of the sealed container 1.

Even if the high-pressure introduction pipe 31 is connected to the sealed container 1, since the electromagnetic on-off valve 32 is closed, the high-pressure gas that fills the sealed container 1 is introduced first from the electromagnetic on-off valve 32. There is no.
The high-pressure gas led to the refrigerant pipe P is condensed in the condenser 25, adiabatically expanded by the expansion mechanism 26, evaporated by the evaporator 27, takes away latent heat of evaporation from the surroundings, and performs a refrigeration (cooling) action. The refrigerant evaporated and reduced in pressure by the evaporator 27 is guided to an accumulator 28 and separated into gas and liquid, and the first compression mechanism 2A and the second compression mechanism 2A are connected to each other via the first suction refrigerant pipe Pa and the second suction refrigerant pipe Pb. Guided to the first cylinder chamber 15a and the second cylinder chamber 15b formed in the compression mechanism 2B.

In the second cylinder chamber 15b, the compression action as described above is performed. The low-pressure refrigerant is guided to the first cylinder chamber 15a, so that the cylinder chamber 15a is in a suction pressure (low pressure) atmosphere. On the other hand, since the blade chamber 16a provided in the cylinder 8A is exposed in the sealed container 1, it is under a discharge pressure (high pressure). The blade 17a has a low pressure condition at the front end and a high pressure condition at the rear end, and a differential pressure exists at both ends.
Under the influence of this differential pressure, the tip of the blade 17a is pressed and urged so as to be in sliding contact with the eccentric roller 14a. That is, the same compression action is performed in the first cylinder chamber 15a as the blade 17b on the second cylinder chamber 15b side is pressed and urged by the spring member 21 to perform the compression action. Eventually, in the compressor section 2, a large capacity operation is performed in which the compression action is performed by both the first compression mechanism 2A and the second compression mechanism 2B.

Next, low-capacity operation when the air conditioning load is small will be described.
The control unit 40 opens the electromagnetic on-off valve 32 provided in the high-pressure introduction pipe 31 and switches and controls the three-way switching valve 30 in a direction communicating with the first cylinder chamber 15a from the high-pressure introduction pipe 31. Then, an operation start signal is sent to the motor unit 3. In the second compression mechanism 2B, the normal compression action is performed as described above, and the high-pressure gas discharged into the sealed container 1 is filled, and the inside of the sealed container 1 becomes high pressure.
The high-pressure gas that fills the sealed container 1 is guided to the refrigerant pipe P and to the high-pressure introduction pipe 31 through the electromagnetic on-off valve 32. The high-pressure gas is guided along the switching direction of the three-way switching valve 30 and is introduced into the first cylinder chamber 15a from the middle of the first suction refrigerant pipe Pa. While the first cylinder chamber 15a is in a discharge pressure (high pressure) atmosphere, the blade chamber 16a remains under the same high pressure condition as that in the sealed container 1. The blade 17a is affected by high pressure at both the front end and the rear end, and there is no differential pressure at both ends.

Therefore, the blade 17a maintains a stopped state without moving at a position separated from the outer peripheral surface of the roller 14a, which is a position kicked by the first rotation of the eccentric roller 14a. Therefore, even if the eccentric roller 14a moves, the compression action is not performed in the first cylinder chamber 15a, and the first compression mechanism 2A is stopped (non-compression operation). Eventually, only the compression action in the second compression mechanism 2B is effective, and the low-capacity operation that halves the large-capacity operation described above is performed.
Note that a part of the high-pressure gas filled in the first cylinder chamber 15a flows back into the accumulator 28 through the first suction refrigerant pipe Pa. However, since the check valve 29 is provided in the suction refrigerant pipe Pa, backflow to the accumulator 28 is prevented. Since the first cylinder chamber 15a is at a high pressure, no leakage of compressed gas from the sealed container 1 to the first cylinder chamber 15a occurs, and no loss is caused thereby. Therefore, low-capacity operation is possible without a decrease in compression efficiency.
The two-cylinder rotary compressor C acting in this way, particularly in the first compression mechanism 2A and the second compression mechanism 2B constituting the compressor section 2, the first discharge port 12a and the second discharge The port 12b is provided in the thin portions d and e formed in the main bearing 9 and the sub-bearing 13. Along with the compression action, it is inevitable that high pressure gas remains in the discharge ports 12a and 12b. In the next suction stroke, the high pressure gas is mixed into the low pressure gas introduced into the cylinder chambers 15a and 15b and is recompressed.

However, in the compressor C, since the discharge ports 12a and 12b are provided in the thin portions d and e, their volumes (passage volumes) can be made as small as possible. The amount of so-called top clearance is reduced, and the volumetric efficiency can be improved by reducing the re-expansion loss. The compression performance is improved, which leads to the improvement of the refrigeration cycle efficiency.
In the first compression mechanism 2A, a distance R1 from the axis of the rotation shaft 4 to the center of the first discharge port 12a is set. Therefore, the recess 10a that accommodates the discharge valve 11a does not bite into the boss portion 9b of the main bearing 9, and only the flange portion 9a is processed.

  That is, the boss portion 9b of the main bearing 9 has no missing portion, and the rotation shaft 4 can be pivotally supported by the entire boss portion. A rotor 6 constituting the electric motor unit 3 is fitted on the rotary shaft 4 immediately above the main bearing 9 and is located adjacent to the main bearing boss portion 9b. However, since there is no fragile portion with respect to the rotational centrifugal force of the rotor 6 in the boss portion 9b, the shaft reliability can be improved.

  In contrast, in the second compression mechanism 2B, a distance R2 from the axis of the rotating shaft 4 to the center of the second discharge port 12b is set. The distance R2 is set smaller than the distance R1.

Therefore, the concave portion 10 b that accommodates the discharge valve 11 b bites into the boss portion 13 b of the auxiliary bearing 13. However, the sub-bearing 13 is located at the position farthest from the motor unit 3 in the compressor unit 2 and pivotally supports the rotary shaft 4, but can receive almost no centrifugal force due to the rotation of the rotor 6 of the motor unit 3. There is no impact on reliability.
By setting the distance R2 to be small, the entire area of the second discharge port 12b opens to the second cylinder chamber 15b, and processing such as the discharge notch 33 in the first cylinder 8A is unnecessary. Become. Since there is no discharge notch, the top clearance is reduced, the re-expansion loss is reduced, the compression performance of the compressor C is further improved, and the refrigeration cycle efficiency is further improved. The second discharge port 12b is not limited to opening the entire area, and the above-described effect can be obtained if approximately 70% or more is open.

FIG. 6A shows the characteristics of the occurrence rate with respect to the annual air conditioning load in the air conditioner. That is, the horizontal axis represents the air conditioning load (operating load), and the vertical axis represents the occurrence rate corresponding to the air conditioning load, which is formed into a bar graph.
As can be seen from the figure, the rate of occurrence increases as the air conditioning load decreases, and the rate of occurrence decreases as the air conditioning load gradually increases. The rate of occurrence is very low at rated capacity or conditions before and after the air conditioning load increases. Specifically, with the increase in housing and buildings that have become highly insulated and airtight in recent years, the load is large at the start of operation (start-up), so a large capacity is required, but the load is stable operation. Long-time operation is accumulated in a small region.
As described above, when the load is large, large capacity operation is performed in which both the first compression mechanism 2A and the second compression mechanism 2B are operated, and when the load is small, the first compression mechanism 2A is not compressed. The low-capacity operation is performed in which only the second compression mechanism 2B is operated. The ratio of performing the large-capacity operation is very small, and there are few opportunities to operate the first compression mechanism 2A. On the other hand, the ratio of performing the low capacity operation is extremely large, and only the second compression mechanism 2B is operated for a long time.

From the above conditions, the first discharge port 12a in the first compression mechanism 2A in which the non-compression operation takes a long time does not need to consider the low capacity condition, and only considers the large capacity operation with a large amount of refrigerant circulation. Good. Further, in the second compression mechanism 2B in which the compression operation is always continued, the second discharge port 12b can be operated with high efficiency by making a design with an emphasis on a low flow rate (low capacity / low frequency). .
As described above, the diameter φDb of the second discharge port 12b provided in the second compression mechanism 2B is smaller than the diameter φDa of the first discharge port 12a in the first compression mechanism 2A (φDb <φDa ) By setting, the above condition can be satisfied.
Although the control unit 40 includes an inverter circuit and controls the rotation speed of the motor unit 3, the control unit 40 is not limited to this and is applied to a two-cylinder rotary compressor operated with a commercial power source. However, similar effects can be obtained. In addition, although the first compression mechanism 2A that can be switched between the non-compression operation and the compression operation is provided, even in the compressor that includes the compression mechanism that cannot be switched, the re-expansion loss is reduced, and the low operation with a high operation rate is achieved. It is also an effective means for improving efficiency at frequency.

FIG. 5 is a partial cross-sectional view of the compressor unit 2 showing a modification of the present embodiment. The same components as those described above are denoted by the same reference numerals and description thereof is omitted.
In the first compression mechanism 2A, the concave portion 10a is provided in the main bearing flange portion 9a, and the first discharge port 12a that is opened and closed by the first discharge valve 11a is provided in the concave portion. In the second compression mechanism 2B, the recess 10b in the sub-bearing flange portion 13a is provided, the second discharge port 12b is opened and closed by the second discharge valve 11b does not change even be provided, wherein the sub Instead of machining the biting part in the bearing boss part 13b , the discharge notch part f is provided in the second thin cylinder 8B.
Further, in the first compression mechanism 2A, a concave refrigerant reservoir 50 is provided from the lower surface of the first cylinder 8A, and a refrigerant guide hole extends between the bottom surface of the refrigerant reservoir 50 and the main bearing flange 9a. 51 is provided. An auxiliary discharge port 52 is provided on the peripheral surface of the refrigerant reservoir 50 and communicates with the first cylinder chamber 15a. The auxiliary discharge port 52 is opened and closed by an auxiliary discharge valve 53.

In the first compression mechanism 2A, when the compression action is performed in the first cylinder chamber 15a, the auxiliary discharge valve 53 opens and closes together with the first discharge valve 11a, and the gas compressed and pressurized in the cylinder chamber 15a is supplied to the first compression mechanism 2A. 1 is discharged directly from the discharge port 12 a to the sealed container 1, and is discharged from the auxiliary discharge port 52 into the sealed container 1 through the refrigerant reservoir 50 and the refrigerant guide hole 51.
In this way, the first compression mechanism 2A includes the first discharge port 12a and the auxiliary discharge port 52, and the total discharge port cross-sectional area is equal to the cross-sectional area of the second discharge port 12b in the second compression mechanism 2B. It was set large in comparison. As described above, the first compression mechanism 2A switches between the compression operation and the non-compression operation according to the load, but the second compression mechanism 2B continuously performs the compression operation.

That is, the continuous operation side (second compression mechanism 2B) is a small discharge passage having an optimal cross-sectional area for use in a low frequency range where the operation rate is high, and the operation switching side (first compression mechanism 2A) is high circulation. Since it is used only in the volume range, it is a large discharge passage that has an optimal cross-sectional area to obtain maximum efficiency at a high operating frequency.
FIG. 6B is a diagram showing the characteristics of the compressor integrated efficiency (= annual electricity cost) with respect to the discharge port cross-sectional area ratio of the first compression mechanism 2A and the second compression mechanism 2B. The discharge port sectional area ratio is the ratio of the sectional area of the second discharge port 12b in the second compression mechanism 2B to the total sectional area of the first discharge port 12a and the auxiliary discharge port 52 in the first compression mechanism 2A. It becomes. As is apparent from the figure, the range of the discharge port cross-sectional area ratio of 1.2 to 2.0 is the peak of the compressor integration efficiency.

Therefore, the discharge port cross-sectional area in the first compression mechanism 2A that can be switched between the compression operation and the non-compression operation is 1.2 to the discharge port cross-sectional area in the second compression mechanism 2B on the side that always continues the compression operation. By setting it to 2.0 times, the two-cylinder rotary compressor equipped with an inverter circuit in the control unit 40 minimizes the performance degradation at the time of high capacity and improves the energy efficiency of low performance operation with high operation efficiency. In this way, the compressor integration efficiency can be maximized.
In the above-described modification, the first compression mechanism 2A includes the two discharge ports of the first discharge port 12a and the auxiliary discharge port 52. However, the present invention is not limited to this, and the first compression mechanism 2A is not limited thereto. The mechanism 2A may include only one discharge port, and the cross-sectional area ratio with the discharge port of the second compression mechanism 2B may be set to be in a range of 1.2 to 2.0.
In addition, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage, and is disclosed in the above-described embodiment. Various inventions can be formed by appropriately combining a plurality of components.

The longitudinal cross-sectional view and refrigeration cycle block diagram of the 2 cylinder type rotary compressor which concern on one embodiment in this invention. The perspective view which decomposed | disassembled some compressor parts based on the embodiment. Sectional drawing which abbreviate | omitted a part of compressor part based on the embodiment. The top view of the subbearing based on the embodiment. The figure which abbreviate | omitted a part of compressor part which shows the modification concerning the embodiment. The characteristic figure of the incidence rate with respect to the air-conditioning load based on the embodiment, and the characteristic figure of the compressor integration efficiency with respect to the discharge port cross-sectional area ratio.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sealed container, 3 ... Electric motor part, 4 ... Rotary shaft, 2 ... Compressor part, 9 ... Main bearing, 2A ... 1st compression mechanism, 7 ... Intermediate partition plate, 2B ... 2nd compression mechanism, 13 ... Sub bearing, 8A ... 1st cylinder, 8B ... 2nd cylinder, 14a, 14b ... Eccentric roller, 15a ... 1st cylinder chamber, 15b ... 2nd cylinder chamber, 17a, 17b ... Blade, 12 ... 1st Discharge port, 12b ... second discharge port, K ... capacity variable mechanism (capacity switching control means), 25 ... condenser, 26 ... expansion mechanism (expansion device), 27 ... evaporator, P ... refrigerant pipe.

Claims (4)

In a two-cylinder rotary compressor that houses a motor unit and a compressor unit composed of two sets of compression mechanisms connected to the motor unit via a rotating shaft in a sealed container,
The compressor part is a combination of a main bearing, a first compression mechanism, an intermediate partition plate, a second compression mechanism, and a sub-bearing in order from the motor part side,
Each of the first compression mechanism and the second compression mechanism includes a cylinder, a cylinder chamber provided in the cylinder and accommodating a roller so as to be eccentrically rotatable, and a tip edge provided in the cylinder contacting a peripheral surface of the roller. A blade that bisects the cylinder chamber along the rotational direction of
The main bearing includes a flange portion attached to the cylinder of the first compression mechanism, and a boss portion that is integrally formed with the flange portion and pivotally supports a part of the rotary shaft. A recessed portion to which the discharge valve is attached is provided, and the thin portion formed between the recessed portion and the other surface of the flange portion is provided with the recessed portion and the central axis aligned with each other and is opened and closed by the first discharge valve. A first discharge port;
The sub-bearing includes a flange portion attached to the cylinder of the second compression mechanism, and a boss portion that is integrally formed with the flange portion and pivotally supports a part of the rotary shaft. A recess to which the discharge valve is attached is provided. A thin portion formed between the recess and the other surface of the flange portion is provided with the center axis aligned with the recess and opened and closed by the second discharge valve. A second discharge port,
The concave portion of the main bearing is provided without biting into the boss portion of the main bearing, and the concave portion of the auxiliary bearing is provided to bite into the boss portion of the auxiliary bearing,
The distance (R2) from the axis of the rotary shaft to the center of the second discharge port provided in the auxiliary bearing is the distance (R1) from the axis of the rotary shaft to the center of the first discharge port provided in the main bearing. Smaller than (R2 <R1) ,
With the setting of the distance (R2), the second discharge port 2 cylinder type rotary compressor 70% or more of the area with respect to the second cylinder, characterized in Rukoto is opened. The first compression mechanism is configured to be capable of switching between a compression operation and a non-compression operation in which the blade is separated from the roller and the compression operation is not performed.
Depending on the magnitude of the load, both the first compression mechanism and the second compression mechanism perform a large capacity operation, and the first compression mechanism is switched to a non-compression operation, and the compression operation is performed only by the second compression operation. 2. A two-cylinder rotary compressor according to claim 1, further comprising a capability switching control means for switching to a low-capacity operation for performing the operation.   The diameter (φDb) of the second discharge port provided in the second compression mechanism is set to be smaller than the diameter (φDa) of the first discharge port in the first compression mechanism (φDb <φDa). The two-cylinder rotary compressor according to any one of claims 1 and 2.   A two-cylinder rotary compressor according to any one of claims 1 to 3, a condenser, an expansion device, and an evaporator are connected via a refrigerant pipe to constitute a refrigeration cycle circuit. Refrigeration cycle equipment.

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